There's more than one way to scan a cat: imaging cat auditory cortex with high-field fMRI using continuous or sparse sampling.

PubMed

Hall, Amee J; Brown, Trecia A; Grahn, Jessica A; Gati, Joseph S; Nixon, Pam L; Hughes, Sarah M; Menon, Ravi S; Lomber, Stephen G

2014-03-15

When conducting auditory investigations using functional magnetic resonance imaging (fMRI), there are inherent potential confounds that need to be considered. Traditional continuous fMRI acquisition methods produce sounds >90 dB which compete with stimuli or produce neural activation masking evoked activity. Sparse scanning methods insert a period of reduced MRI-related noise, between image acquisitions, in which a stimulus can be presented without competition. In this study, we compared sparse and continuous scanning methods to identify the optimal approach to investigate acoustically evoked cortical, thalamic and midbrain activity in the cat. Using a 7 T magnet, we presented broadband noise, 10 kHz tones, or 0.5 kHz tones in a block design, interleaved with blocks in which no stimulus was presented. Continuous scanning resulted in larger clusters of activation and more peak voxels within the auditory cortex. However, no significant activation was observed within the thalamus. Also, there was no significant difference found, between continuous or sparse scanning, in activations of midbrain structures. Higher magnitude activations were identified in auditory cortex compared to the midbrain using both continuous and sparse scanning. These results indicate that continuous scanning is the preferred method for investigations of auditory cortex in the cat using fMRI. Also, choice of method for future investigations of midbrain activity should be driven by other experimental factors, such as stimulus intensity and task performance during scanning. Copyright © 2014 Elsevier B.V. All rights reserved.

Examining a New Method to Studying Velopharyngeal Structures in a Child With 22q11.2 Deletion Syndrome.

PubMed

Kollara, Lakshmi; Schenck, Graham; Jaskolka, Michael; Perry, Jamie L

2017-04-14

To date, no studies have imaged the velopharynx in children with 22q11.2 deletion syndrome (22q11.2 DS) without the use of sedation. Dysmorphology in velopharyngeal structures has been shown to have significant negative implications on speech among these individuals. This single case study was designed to assess the feasibility of a child-friendly magnetic resonance imaging (MRI) scanning protocol in this clinically challenging population and to determine the utility of this MRI protocol for future work in this area. One 6-year-old White girl diagnosed with 22q11.2 DS was imaged using a child-friendly, nonsedated MRI protocol. Quantitative and qualitative measures of the velopharyngeal area and associated structures were evaluated, and comparisons were made to age-matched control subjects with normal velopharyngeal anatomy. MRI data were successfully obtained using the child-friendly scanning protocol in the subject in the present study. Quantitative and qualitative differences of the levator muscle and associated velopharyngeal structures were noted. Using these MRI and structural analyses methods, insights related to muscle morphology can be obtained and considered as part of the research and clinical examination of children with 22q11.2 DS. The imaging protocol described in this study presents an effective means to counteract difficulties in imaging young children.

Standardization of Analysis Sets for Reporting Results from ADNI MRI Data

PubMed Central

Wyman, Bradley T.; Harvey, Danielle J.; Crawford, Karen; Bernstein, Matt A.; Carmichael, Owen; Cole, Patricia E.; Crane, Paul; DeCarli, Charles; Fox, Nick C.; Gunter, Jeffrey L.; Hill, Derek; Killiany, Ronald J.; Pachai, Chahin; Schwarz, Adam J.; Schuff, Norbert; Senjem, Matthew L.; Suhy, Joyce; Thompson, Paul M.; Weiner, Michael; Jack, Clifford R.

2013-01-01

The ADNI 3D T1-weighted MRI acquisitions provide a rich dataset for developing and testing analysis techniques for extracting structural endpoints. To promote greater rigor in analysis and meaningful comparison of different algorithms, the ADNI MRI Core has created standardized analysis sets of data comprising scans that met minimum quality control requirements. We encourage researchers to test and report their techniques against these data. Standard analysis sets of volumetric scans from ADNI-1 have been created, comprising: screening visits, 1 year completers (subjects who all have screening, 6 and 12 month scans), two year annual completers (screening, 1, and 2 year scans), two year completers (screening, 6 months, 1 year, 18 months (MCI only) and 2 years) and complete visits (screening, 6 months, 1 year, 18 months (MCI only), 2, and 3 year (normal and MCI only) scans). As the ADNI-GO/ADNI-2 data becomes available, updated standard analysis sets will be posted regularly. PMID:23110865

Magnetic Resonance Imaging (MRI)

MedlinePlus

... MoreBMI Calculator Complete Blood Count (CBC)Blood Test: Lipid PanelRapid Strep TestPelvic UltrasoundAbdominal UltrasoundCT Head ScanPap Smear ( ... because it can provide images of internal body structures. It is more like a CT scan than ...

Automatic segmentation of left ventricle in cardiac cine MRI images based on deep learning

NASA Astrophysics Data System (ADS)

Zhou, Tian; Icke, Ilknur; Dogdas, Belma; Parimal, Sarayu; Sampath, Smita; Forbes, Joseph; Bagchi, Ansuman; Chin, Chih-Liang; Chen, Antong

2017-02-01

In developing treatment of cardiovascular diseases, short axis cine MRI has been used as a standard technique for understanding the global structural and functional characteristics of the heart, e.g. ventricle dimensions, stroke volume and ejection fraction. To conduct an accurate assessment, heart structures need to be segmented from the cine MRI images with high precision, which could be a laborious task when performed manually. Herein a fully automatic framework is proposed for the segmentation of the left ventricle from the slices of short axis cine MRI scans of porcine subjects using a deep learning approach. For training the deep learning models, which generally requires a large set of data, a public database of human cine MRI scans is used. Experiments on the 3150 cine slices of 7 porcine subjects have shown that when comparing the automatic and manual segmentations the mean slice-wise Dice coefficient is about 0.930, the point-to-curve error is 1.07 mm, and the mean slice-wise Hausdorff distance is around 3.70 mm, which demonstrates the accuracy and robustness of the proposed inter-species translational approach.

Animated educational video to prepare children for MRI without sedation: evaluation of the appeal and value.

PubMed

Szeszak, Szofia; Man, Rachel; Love, Andrew; Langmack, Gill; Wharrad, Heather; Dineen, Robert A

2016-11-01

MRI scans can be distressing for children and often require sedation. Educating children about what to expect reduces anxiety and increases likelihood of successful non-sedated MRI scans. Multimedia tools are a popular means of education. Animated video could provide a free, accessible method of preparing children for MRI scans. To evaluate a new animation video for preparing children for MRI, specifically for decreasing in-scanner motion and examination failure. We recruited 24 healthy children ages 5-11 years. Participants underwent pre- and post-viewing questionnaires and structured interviews. We then compared median Likert scale score changes between pre- and post-animation questions and analyzed the interview framework. Participants were filmed viewing the animation to calculate time spent looking at the screen to assess how well the video retained children's attention. There were significant improvements in median scores regarding what to expect, checking for metal and keeping still. There were no significant changes in other knowledge-based topics. There were significant improvements in median scores for anxiety-based topics. On average, children watched the screen for 98.9% of the 174-s animation. The animation improved knowledge, reduced anxiety, retained attention and was enjoyed by participants. It can be accessed freely via the Internet to help prepare children ages 5-11 for having an MRI scan.

Changes in Gray Matter Density, Regional Homogeneity, and Functional Connectivity in Methamphetamine-Associated Psychosis: A Resting-State Functional Magnetic Resonance Imaging (fMRI) Study.

PubMed

Zhang, Shengyu; Hu, Qiang; Tang, Tao; Liu, Chao; Li, Chengchong; Zang, Yin-Yin; Cai, Wei-Xiong

2018-06-13

BACKGROUND Using regional homogeneity (ReHo) blood oxygen level-dependent functional MR (BOLD-fMRI), we investigated the structural and functional alterations of brain regions among patients with methamphetamine-associated psychosis (MAP). MATERIAL AND METHODS This retrospective study included 17 MAP patients, 16 schizophrenia (SCZ) patients, and 18 healthy controls. Informed consent was obtained from all patients before the clinical assessment, the severity of clinical symptoms was evaluated prior to the fMRI scanning, and then images were acquired and preprocessed after each participant received 6-min fRMI scanning. The participants all underwent BOLD-fMRI scanning. Voxel-based morphometry was used to measure gray matter density (GMD). Resting-state fMRI (rs-fMRI) was conducted to analyze functional MR, ReHo, and functional connectivity (FC). RESULTS GMD analysis results suggest that MAP patients, SCZ patients, and healthy volunteers show different GMDs within different brain regions. Similarly, the ReHo analysis results suggest that MAP patients, SCZ patients, and healthy volunteers have different GMDs within different brain regions. Negative correlations were found between ReHo- and the PANSS-positive scores within the left orbital interior frontal gyrus (L-orb-IFG) of MAP patients. ReHo- and PANSS-negative scores of R-SFG were negatively correlated among SCZ patients. The abnormal FC of R-MFG showed a negative correlation with the PANSS score among MAP patients. CONCLUSIONS The abnormalities in brain structure and FC were associated with the development of MAP.

Real time 3D visualization of intraoperative organ deformations using structured dictionary.

PubMed

Wang, Dan; Tewfik, Ahmed H

2012-04-01

Restricted visualization of the surgical field is one of the most critical challenges for minimally invasive surgery (MIS). Current intraoperative visualization systems are promising. However, they can hardly meet the requirements of high resolution and real time 3D visualization of the surgical scene to support the recognition of anatomic structures for safe MIS procedures. In this paper, we present a new approach for real time 3D visualization of organ deformations based on optical imaging patches with limited field-of-view and a single preoperative scan of magnetic resonance imaging (MRI) or computed tomography (CT). The idea for reconstruction is motivated by our empirical observation that the spherical harmonic coefficients corresponding to distorted surfaces of a given organ lie in lower dimensional subspaces in a structured dictionary that can be learned from a set of representative training surfaces. We provide both theoretical and practical designs for achieving these goals. Specifically, we discuss details about the selection of limited optical views and the registration of partial optical images with a single preoperative MRI/CT scan. The design proposed in this paper is evaluated with both finite element modeling data and ex vivo experiments. The ex vivo test is conducted on fresh porcine kidneys using 3D MRI scans with 1.2 mm resolution and a portable laser scanner with an accuracy of 0.13 mm. Results show that the proposed method achieves a sub-3 mm spatial resolution in terms of Hausdorff distance when using only one preoperative MRI scan and the optical patch from the single-sided view of the kidney. The reconstruction frame rate is between 10 frames/s and 39 frames/s depending on the complexity of the test model.

Recent neuroimaging techniques in mild traumatic brain injury.

PubMed

Belanger, Heather G; Vanderploeg, Rodney D; Curtiss, Glenn; Warden, Deborah L

2007-01-01

Mild traumatic brain injury (TBI) is characterized by acute physiological changes that result in at least some acute cognitive difficulties and typically resolve by 3 months postinjury. Because the majority of mild TBI patients have normal structural magnetic resonance imaging (MRI)/computed tomography (CT) scans, there is increasing attention directed at finding objective physiological correlates of persistent cognitive and neuropsychiatric symptoms through experimental neuroimaging techniques. The authors review studies utilizing these techniques in patients with mild TBI; these techniques may provide more sensitive assessment of structural and functional abnormalities following mild TBI. Particular promise is evident with fMRI, PET, and SPECT scanning, as demonstrated by associations between brain activation and clinical outcomes.

Brief Report: Methods for Acquiring Structural MRI Data in Very Young Children with Autism Without the Use of Sedation

PubMed Central

Simon, Tony J.; Zierhut, Cynthia; Solomon, Marjorie; Rogers, Sally J.; Amaral, David G.

2016-01-01

We describe a protocol with which we achieved a 93% success rate in acquiring high quality MRI scans without the use of sedation in 2.5–4.5 year old children with autism, developmental delays, and typical development. Our main strategy was to conduct MRIs during natural nocturnal sleep in the evenings after the child's normal bedtime. Alternatively, with some older and higher functioning children, the MRI was conducted while the child was awake and watching a video. Both strategies relied heavily on the creation of a child and family friendly MRI environment and the involvement of parents as collaborators in the project. Scanning very young children with autism, typical development, and developmental delays without the use of sedation or anesthesia was possible in the majority of cases. PMID:18157624

Simultaneous CT-MRI Reconstruction for Constrained Imaging Geometries using Structural Coupling and Compressive Sensing

PubMed Central

Xi, Yan; Zhao, Jun; Bennett, James R.; Stacy, Mitchel R.; Sinusas, Albert J.; Wang, Ge

2016-01-01

Objective A unified reconstruction framework is presented for simultaneous CT-MRI reconstruction. Significance Combined CT-MRI imaging has the potential for improved results in existing preclinical and clinical applications, as well as opening novel research directions for future applications. Methods In an ideal CT-MRI scanner, CT and MRI acquisitions would occur simultaneously, and hence would be inherently registered in space and time. Alternatively, separately acquired CT and MRI scans can be fused to simulate an instantaneous acquisition. In this study, structural coupling and compressive sensing techniques are combined to unify CT and MRI reconstructions. A bidirectional image estimation method was proposed to connect images from different modalities. Hence, CT and MRI data serve as prior knowledge to each other for better CT and MRI image reconstruction than what could be achieved with separate reconstruction. Results Our integrated reconstruction methodology is demonstrated with numerical phantom and real-dataset based experiments, and has yielded promising results. PMID:26672028

Dental magnetic resonance imaging: making the invisible visible.

PubMed

Idiyatullin, Djaudat; Corum, Curt; Moeller, Steen; Prasad, Hari S; Garwood, Michael; Nixdorf, Donald R

2011-06-01

Clinical dentistry is in need of noninvasive and accurate diagnostic methods to better evaluate dental pathosis. The purpose of this work was to assess the feasibility of a recently developed magnetic resonance imaging (MRI) technique, called SWeep Imaging with Fourier Transform (SWIFT), to visualize dental tissues. Three in vitro teeth, representing a limited range of clinical conditions of interest, imaged using a 9.4T system with scanning times ranging from 100 seconds to 25 minutes. In vivo imaging of a subject was performed using a 4T system with a 10-minute scanning time. SWIFT images were compared with traditional two-dimensional radiographs, three-dimensional cone-beam computed tomography (CBCT) scanning, gradient-echo MRI technique, and histological sections. A resolution of 100 μm was obtained from in vitro teeth. SWIFT also identified the presence and extent of dental caries and fine structures of the teeth, including cracks and accessory canals, which are not visible with existing clinical radiography techniques. Intraoral positioning of the radiofrequency coil produced initial images of multiple adjacent teeth at a resolution of 400 μm. SWIFT MRI offers simultaneous three-dimensional hard- and soft-tissue imaging of teeth without the use of ionizing radiation. Furthermore, it has the potential to image minute dental structures within clinically relevant scanning times. This technology has implications for endodontists because it offers a potential method to longitudinally evaluate teeth where pulp and root structures have been regenerated. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

The Age-ility Project (Phase 1): Structural and functional imaging and electrophysiological data repository.

PubMed

Karayanidis, Frini; Keuken, Max C; Wong, Aaron; Rennie, Jaime L; de Hollander, Gilles; Cooper, Patrick S; Ross Fulham, W; Lenroot, Rhoshel; Parsons, Mark; Phillips, Natalie; Michie, Patricia T; Forstmann, Birte U

2016-01-01

Our understanding of the complex interplay between structural and functional organisation of brain networks is being advanced by the development of novel multi-modal analyses approaches. The Age-ility Project (Phase 1) data repository offers open access to structural MRI, diffusion MRI, and resting-state fMRI scans, as well as resting-state EEG recorded from the same community participants (n=131, 15-35 y, 66 male). Raw imaging and electrophysiological data as well as essential demographics are made available via the NITRC website. All data have been reviewed for artifacts using a rigorous quality control protocol and detailed case notes are provided. Copyright © 2015. Published by Elsevier Inc.

A simple anaesthetic and monitoring system for magnetic resonance imaging.

PubMed

Rejger, V S; Cohn, B F; Vielvoye, G J; de Raadt, F B

1989-09-01

Clinical magnetic resonance imaging (MRI) is a digital tomographic technique which utilizes radio waves emitted by hydrogen protons in a powerful magnetic field to form an image of soft-tissue structures and abnormalities within the body. Unfortunately, because of the relatively long scanning time required and the narrow deep confines of the MRI tunnel and Faraday cage, some patients cannot be examined without the use of heavy sedation or general anaesthesia. Due to poor access to the patient and the strong magnetic field, several problems arise in monitoring and administering anaesthesia during this procedure. In this presentation these problems and their solutions, as resolved by our institution, are discussed. Of particular interest is the anaesthesia circuit specifically adapted for use during MRI scanning.

Quantitative oxygen extraction fraction from 7-Tesla MRI phase: reproducibility and application in multiple sclerosis.

PubMed

Fan, Audrey P; Govindarajan, Sindhuja T; Kinkel, R Philip; Madigan, Nancy K; Nielsen, A Scott; Benner, Thomas; Tinelli, Emanuele; Rosen, Bruce R; Adalsteinsson, Elfar; Mainero, Caterina

2015-01-01

Quantitative oxygen extraction fraction (OEF) in cortical veins was studied in patients with multiple sclerosis (MS) and healthy subjects via magnetic resonance imaging (MRI) phase images at 7 Tesla (7 T). Flow-compensated, three-dimensional gradient-echo scans were acquired for absolute OEF quantification in 23 patients with MS and 14 age-matched controls. In patients, we collected T2*-weighted images for characterization of white matter, deep gray matter, and cortical lesions, and also assessed cognitive function. Variability of OEF across readers and scan sessions was evaluated in a subset of volunteers. OEF was averaged from 2 to 3 pial veins in the sensorimotor, parietal, and prefrontal cortical regions for each subject (total of ~10 vessels). We observed good reproducibility of mean OEF, with intraobserver coefficient of variation (COV)=2.1%, interobserver COV=5.2%, and scan-rescan COV=5.9%. Patients exhibited a 3.4% reduction in cortical OEF relative to controls (P=0.0025), which was not different across brain regions. Although oxygenation did not relate with measures of structural tissue damage, mean OEF correlated with a global measure of information processing speed. These findings suggest that cortical OEF from 7-T MRI phase is a reproducible metabolic biomarker that may be sensitive to different pathologic processes than structural MRI in patients with MS.

Cortical Thickness Change in Autism during Early Childhood

PubMed Central

Smith, Elizabeth; Thurm, Audrey; Greenstein, Deanna; Farmer, Cristan; Swedo, Susan; Giedd, Jay; Raznahan, Armin

2016-01-01

Structural magnetic resonance imaging (MRI) scans at high spatial resolution can detect potential foci of early brain dysmaturation in children with autism spectrum disorders (ASD). In addition, comparison between MRI and behavior measures over time can identify patterns of brain change accompanying specific outcomes. We report structural MRI data from two time points for a total of 84 scans in children with ASD and 30 scans in typical controls (mean age time one=4.1 years, mean age at time two=6.6 years). Surface-based cortical morphometry and linear mixed effects models were used to link changes in cortical anatomy to both diagnostic status and individual differences in changes in language and autism severity. Compared to controls, children with ASD showed accelerated gray matter volume gain with age, which was driven by a lack of typical age-related cortical thickness (CT) decrease within ten cortical regions involved in language, social cognition and behavioral control. Greater expressive communication gains with age in children with ASD were associated with greater CT gains in a set of right hemisphere homologues to dominant language cortices, potentially identifying a compensatory system for closer translational study. PMID:27061356

The first week after concussion: Blood flow, brain function and white matter microstructure.

PubMed

Churchill, Nathan W; Hutchison, Michael G; Richards, Doug; Leung, General; Graham, Simon J; Schweizer, Tom A

2017-01-01

Concussion is a major health concern, associated with short-term deficits in physical function, emotion and cognition, along with negative long-term health outcomes. However, we remain in the early stages of characterizing MRI markers of concussion, particularly during the first week post-injury when symptoms are most severe. In this study, 52 varsity athletes were scanned using Magnetic Resonance Imaging (MRI), including 26 athletes with acute concussion (scanned 1-7 days post-injury) and 26 matched control athletes. A comprehensive set of functional and structural MRI measures were analyzed, including cerebral blood flow (CBF) and global functional connectivity (Gconn) of grey matter, along with fractional anisotropy (FA) and mean diffusivity (MD) of white matter. An analysis comparing acutely concussed athletes and controls showed limited evidence for reliable mean effects of acute concussion, with only MD showing spatially extensive differences between groups. We subsequently demonstrated that the number of days post-injury explained a significant proportion of inter-subject variability in MRI markers of acutely concussed athletes. Athletes scanned at early acute injury (1-3 days) had elevated CBF and Gconn and reduced FA, but those scanned at late acute injury (5-7 days) had the opposite response. In contrast, MD showed a more complex, spatially-dependent relationship with days post-injury. These novel findings highlight the variability of MRI markers during the acute phase of concussion and the critical importance of considering the acute injury time interval, which has significant implications for studies relating acute MRI data to concussion outcomes.

[Nuclear magnetic resonance of anorectal malformations and persistent postoperative fecal incontinence].

PubMed

de Agustín, J C; Alami, H; Lassaletta, L; Gámez, M; Fernández, A; Fraile, E; Alenda, J G; Rollán, V; Utrilla, J G

1992-07-01

We review our experience with Magnetic Resonance Imaging (MRI) in the evaluation of 6 patients showing anorectal malformation, and 4 more with persistent postoperative fecal incontinence. Preoperative sagittal, axial and coronal planes were studied with special consideration to the pelvic and vertebral structures. The excellent resolution of MRI allowed accurate identification of the pelvic musculature in all patients, including those with bizarre sacral abnormalities. MRI revealed structural anomalies not detected previously, such as teathering cord, intraspinal lipoma, presacral mass and renal malformation. In our institution, MRI has replaced the CT scan in the study of patients suffering of persistent fecal incontinence. In non operated on cases of anorectal malformations, MRI determines with extraordinary accuracy the location of the rectal atretic pouch, the actual pelvic muscular quality, and the detection of previously unsuspected associated anomalies.

EARLY VERSUS LATE MRI IN ASPHYXIATED NEWBORNS TREATED WITH HYPOTHERMIA

PubMed Central

Wintermark, Pia; Hansen, Anne; Soul, Janet; Labrecque, Michelle; Robertson, Richard L.; Warfield, Simon K.

2012-01-01

Objective The purposes of this feasibility study are to assess: (1) the potential utility of early brain magnetic resonance imaging (MRI) in asphyxiated newborns treated with hypothermia; (2) whether early MRI predicts later brain injury observed in these newborns after hypothermia is completed; and (3) whether early MRI indicators of brain injury in these newborns represent reversible changes. Patients and Methods All consecutive asphyxiated term newborns meeting the criteria for therapeutic hypothermia were enrolled prospectively. Each of them underwent 1–2 “early” MRI scans while receiving hypothermia, on day of life (DOL) 1 and DOL 2–3, and also 1–2 “late” MRI scans on DOL 8–13 and at 1 month of age. Results Thirty-seven MRI scans were obtained in twelve asphyxiated neonates treated with induced hypothermia. Four newborns did develop MRI evidence of brain injury, already visible on early MRI scans. The remaining eight newborns did not develop significant MRI evidence of brain injury on any of the MRI scans. In addition, two patients displayed unexpected findings on early MRIs, leading to early termination of hypothermia treatment. Conclusions MRI scans obtained on DOL 2–3 during hypothermia seem to predict later brain injuries in asphyxiated newborns in this feasibility study. Brain injuries identified during this early time appear to represent irreversible changes. Early MRI scans might also be useful to demonstrate unexpected findings not related to hypoxic-ischemic encephalopathy, which could potentially be exacerbated by induced hypothermia. Additional studies with larger numbers of patients will be useful to more definitively confirm these results. PMID:20688865

Three-dimensional liver motion tracking using real-time two-dimensional MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brix, Lau, E-mail: lau.brix@stab.rm.dk; Ringgaard, Steffen; Sørensen, Thomas Sangild

2014-04-15

Purpose: Combined magnetic resonance imaging (MRI) systems and linear accelerators for radiotherapy (MR-Linacs) are currently under development. MRI is noninvasive and nonionizing and can produce images with high soft tissue contrast. However, new tracking methods are required to obtain fast real-time spatial target localization. This study develops and evaluates a method for tracking three-dimensional (3D) respiratory liver motion in two-dimensional (2D) real-time MRI image series with high temporal and spatial resolution. Methods: The proposed method for 3D tracking in 2D real-time MRI series has three steps: (1) Recording of a 3D MRI scan and selection of a blood vessel (ormore » tumor) structure to be tracked in subsequent 2D MRI series. (2) Generation of a library of 2D image templates oriented parallel to the 2D MRI image series by reslicing and resampling the 3D MRI scan. (3) 3D tracking of the selected structure in each real-time 2D image by finding the template and template position that yield the highest normalized cross correlation coefficient with the image. Since the tracked structure has a known 3D position relative to each template, the selection and 2D localization of a specific template translates into quantification of both the through-plane and in-plane position of the structure. As a proof of principle, 3D tracking of liver blood vessel structures was performed in five healthy volunteers in two 5.4 Hz axial, sagittal, and coronal real-time 2D MRI series of 30 s duration. In each 2D MRI series, the 3D localization was carried out twice, using nonoverlapping template libraries, which resulted in a total of 12 estimated 3D trajectories per volunteer. Validation tests carried out to support the tracking algorithm included quantification of the breathing induced 3D liver motion and liver motion directionality for the volunteers, and comparison of 2D MRI estimated positions of a structure in a watermelon with the actual positions. Results: Axial, sagittal, and coronal 2D MRI series yielded 3D respiratory motion curves for all volunteers. The motion directionality and amplitude were very similar when measured directly as in-plane motion or estimated indirectly as through-plane motion. The mean peak-to-peak breathing amplitude was 1.6 mm (left-right), 11.0 mm (craniocaudal), and 2.5 mm (anterior-posterior). The position of the watermelon structure was estimated in 2D MRI images with a root-mean-square error of 0.52 mm (in-plane) and 0.87 mm (through-plane). Conclusions: A method for 3D tracking in 2D MRI series was developed and demonstrated for liver tracking in volunteers. The method would allow real-time 3D localization with integrated MR-Linac systems.« less

Identification and characterisation of midbrain nuclei using optimised functional magnetic resonance imaging

PubMed Central

Limbrick-Oldfield, Eve H.; Brooks, Jonathan C.W.; Wise, Richard J.S.; Padormo, Francesco; Hajnal, Jo V.; Beckmann, Christian F.; Ungless, Mark A.

2012-01-01

Localising activity in the human midbrain with conventional functional MRI (fMRI) is challenging because the midbrain nuclei are small and located in an area that is prone to physiological artefacts. Here we present a replicable and automated method to improve the detection and localisation of midbrain fMRI signals. We designed a visual fMRI task that was predicted would activate the superior colliculi (SC) bilaterally. A limited number of coronal slices were scanned, orientated along the long axis of the brainstem, whilst simultaneously recording cardiac and respiratory traces. A novel anatomical registration pathway was used to optimise the localisation of the small midbrain nuclei in stereotactic space. Two additional structural scans were used to improve registration between functional and structural T1-weighted images: an echo-planar image (EPI) that matched the functional data but had whole-brain coverage, and a whole-brain T2-weighted image. This pathway was compared to conventional registration pathways, and was shown to significantly improve midbrain registration. To reduce the physiological artefacts in the functional data, we estimated and removed structured noise using a modified version of a previously described physiological noise model (PNM). Whereas a conventional analysis revealed only unilateral SC activity, the PNM analysis revealed the predicted bilateral activity. We demonstrate that these methods improve the measurement of a biologically plausible fMRI signal. Moreover they could be used to investigate the function of other midbrain nuclei. PMID:21867762

Is There a Role for MRI in Plantar Heel Pain.

PubMed

Fazal, Muhammad Ali; Tsekes, Demetris; Baloch, Irshad

2018-06-01

There is an increasing trend to investigate plantar heel pain with magnetic resonance imaging (MRI) scan though plantar fasciitis is the most common cause. The purpose of our study was to evaluate the role of MRI in patients presenting with plantar heel pain. Case notes and MRI scans of 141 patients with a clinical diagnosis of plantar fasciitis were reviewed retrospectively. There were 98 females and 43 males patients. Fourteen patients had bilateral symptoms. Average age for male patients was 51 years (range = 26-78 years), and for female patients the average age was 52 years (range = 29-76 years). A total of 121 feet had MRI features suggestive of plantar fasciitis. MRI was normal in 32 feet. There was one case of stress fracture of calcaneus and another of a heel fibroma diagnosed on MRI scan. In our study, MRI scan was normal in 20.7% of the cases; 1.3% had a diagnosis other than plantar fasciitis but no sinister pathology. We therefore conclude that MRI scan is not routinely indicated and key is careful clinical assessment. Therapeutic, Level IV: Retrospective, Case series.

Neural reactivity to visual food stimuli is reduced in some areas of the brain during evening hours compared to morning hours: an fMRI study in women.

PubMed

Masterson, Travis D; Kirwan, C Brock; Davidson, Lance E; LeCheminant, James D

2016-03-01

The extent that neural responsiveness to visual food stimuli is influenced by time of day is not well examined. Using a crossover design, 15 healthy women were scanned using fMRI while presented with low- and high-energy pictures of food, once in the morning (6:30-8:30 am) and once in the evening (5:00-7:00 pm). Diets were identical on both days of the fMRI scans and were verified using weighed food records. Visual analog scales were used to record subjective perception of hunger and preoccupation with food prior to each fMRI scan. Six areas of the brain showed lower activation in the evening to both high- and low-energy foods, including structures in reward pathways (P < 0.05). Nine brain regions showed significantly higher activation for high-energy foods compared to low-energy foods (P < 0.05). High-energy food stimuli tended to produce greater fMRI responses than low-energy food stimuli in specific areas of the brain, regardless of time of day. However, evening scans showed a lower response to both low- and high-energy food pictures in some areas of the brain. Subjectively, participants reported no difference in hunger by time of day (F = 1.84, P = 0.19), but reported they could eat more (F = 4.83, P = 0.04) and were more preoccupied with thoughts of food (F = 5.51, P = 0.03) in the evening compared to the morning. These data underscore the role that time of day may have on neural responses to food stimuli. These results may also have clinical implications for fMRI measurement in order to prevent a time of day bias.

Functional anatomy of the prostate: implications for treatment planning.

PubMed

McLaughlin, Patrick W; Troyer, Sara; Berri, Sally; Narayana, Vrinda; Meirowitz, Amichay; Roberson, Peter L; Montie, James

2005-10-01

To summarize the functional anatomy relevant to prostate cancer treatment planning. Coronal, axial, and sagittal T2 magnetic resonance imaging (MRI) and MRI angiography were fused by mutual information and registered with computed tomography (CT) scan data sets to improve definition of zonal anatomy of the prostate and critical adjacent structures. The three major prostate zones (inner, outer, and anterior fibromuscular) are visible by T2 MRI imaging. The bladder, bladder neck, and internal (preprostatic) sphincter are a continuous muscular structure and clear definition of the preprostatic sphincter is difficult by MRI. Transition zone hypertrophy may efface the bladder neck and internal sphincter. The external "lower" sphincter is clearly visible by T2 MRI with wide variations in length. The critical erectile structures are the internal pudendal artery (defined by MRI angiogram or T2 MRI), corpus cavernosum, and neurovascular bundle. The neurovascular bundle is visible along the posterior lateral surface of the prostate on CT and MRI, but its terminal branches (cavernosal nerves) are not visible and must be defined by their relationship to the urethra within the genitourinary diaphragm. Visualization of the ejaculatory ducts within the prostate is possible on sagittal MRI. The anatomy of the prostate-rectum interface is clarified by MRI, as is the potentially important distinction of rectal muscle and rectal mucosa. Improved understanding of functional anatomy and imaging of the prostate and critical adjacent structures will improve prostate radiation therapy by improvement of dose and toxicity correlation, limitation of dose to critical structures, and potential improvement in post therapy quality of life.

MR to CT registration of brains using image synthesis

NASA Astrophysics Data System (ADS)

Roy, Snehashis; Carass, Aaron; Jog, Amod; Prince, Jerry L.; Lee, Junghoon

2014-03-01

Computed tomography (CT) is the preferred imaging modality for patient dose calculation for radiation therapy. Magnetic resonance (MR) imaging (MRI) is used along with CT to identify brain structures due to its superior soft tissue contrast. Registration of MR and CT is necessary for accurate delineation of the tumor and other structures, and is critical in radiotherapy planning. Mutual information (MI) or its variants are typically used as a similarity metric to register MRI to CT. However, unlike CT, MRI intensity does not have an accepted calibrated intensity scale. Therefore, MI-based MR-CT registration may vary from scan to scan as MI depends on the joint histogram of the images. In this paper, we propose a fully automatic framework for MR-CT registration by synthesizing a synthetic CT image from MRI using a co-registered pair of MR and CT images as an atlas. Patches of the subject MRI are matched to the atlas and the synthetic CT patches are estimated in a probabilistic framework. The synthetic CT is registered to the original CT using a deformable registration and the computed deformation is applied to the MRI. In contrast to most existing methods, we do not need any manual intervention such as picking landmarks or regions of interests. The proposed method was validated on ten brain cancer patient cases, showing 25% improvement in MI and correlation between MR and CT images after registration compared to state-of-the-art registration methods.

Diagnosis of dementia--automatic quantification of brain structures.

PubMed

Engedal, Knut; Brækhus, Anne; Andreassen, Ole A; Nakstad, Per Hj

2012-08-21

The aim of the present study was to examine the usefulness of a fully automatic quantification of brain structures by means of magnetic resonance imaging (MRI) for diagnosing dementia of the Alzheimer's type (DAT). MRI scans of the brains of 122 patients, referred to a memory clinic, were analysed using Neuroquant® software, which quantifies the volume of various brain structures. Clinical diagnoses were made by two doctors without knowledge of the MRI results. We performed Receiver Operating Characteristic analyses and calculated the area under the curve (AUC). A value of 1 means that all ill patients have been diagnosed as diseased and no patient has been falsely diagnosed as diseased. The mean age of the patients was 67.2 years (SD 10.5 years), 60 % were men, 63 had DAT, 24 had another type of dementia, 25 had mild cognitive impairment (MCI) and ten had subjective cognitive impairment (SCI). In the comparison between DAT patients and patients with SCI or MCI, seven of eleven volumes were significantly larger than AUC 0.5. Positive and negative likelihood ratios were less than 5 and more than 0.2, respectively, for the best limit values of the volumes. Apart from the cerebellum (AUC 0.67), none of the brain structures was significantly different from AUC 0.5 in patients with dementia conditions other than dementia Alzheimer's type. MRI scans with Neuroquant analyses cannot be used alone to distinguish between persons with dementia of Alzheimer's type and persons without dementia.

Magnetic Resonance Imaging in Psoriatic Arthritis: A Descriptive Study of Indications, Features and Effect on Treatment Change.

PubMed

Maldonado-Ficco, Hernán; Sheane, Barry J; Thavaneswaran, Arane; Chandran, Vinod; Gladman, Dafna D

2017-08-01

The aims of this study were to describe the indications for, and features of, axial/peripheral joint magnetic resonance imaging (MRI) in psoriatic arthritis (PsA) and to examine the influence of MRI findings on clinical practice. All axial and peripheral (hand and/or foot) MRI scans on patients attending the Toronto PsA clinic l between 2003 and 2014 were included. Scan details were garnered from the radiologist's official report. A chart review was performed to determine if MRI findings contributed to a change of treatment. One hundred sixty-eight scans were performed on 125 patients (135 axial and 33 peripheral). The mean age was 50.5 (SD, 11.5) years, with 51.2% being female. Mean duration of PsA was 11.2 (SD, 10.9) years. Of the axial scans, the majority were performed on the whole spine (excluding the sacrum) (27.4%) or the sacroiliac joints and spine together (45.2%). The predominant indications were for suspected inflammatory (51.1%) or degenerative (24.4%) disease. Magnetic resonance imaging revealed inflammatory and/or structural change in 34.1% versus 54.8% with degenerative changes. In MRI axial inflammation (n = 25), the majority (48%) had sacroiliac joint involvement, whereas 28% had inflammation at 2 or more sites.Of the periphery, 60.6% of scans were on hands and 21.2% were on feet alone. The main indications were for suspected subclinical synovitis (78.8%). Inflammatory arthritis was the MRI diagnosis in 72.7%. Magnetic resonance imaging findings influenced treatment change (n = 32) in 56.3%, but were insufficient to effect treatment change without clinical findings (100%). Magnetic resonance imaging is useful in evaluating patients with active PsA, particularly when suspecting inflammation and radiographic findings are unhelpful. In some cases, it can be used as an adjunct to clinical examination in determining treatment change.

A computational atlas of the hippocampal formation using ex vivo, ultra-high resolution MRI: Application to adaptive segmentation of in vivo MRI.

PubMed

Iglesias, Juan Eugenio; Augustinack, Jean C; Nguyen, Khoa; Player, Christopher M; Player, Allison; Wright, Michelle; Roy, Nicole; Frosch, Matthew P; McKee, Ann C; Wald, Lawrence L; Fischl, Bruce; Van Leemput, Koen

2015-07-15

Automated analysis of MRI data of the subregions of the hippocampus requires computational atlases built at a higher resolution than those that are typically used in current neuroimaging studies. Here we describe the construction of a statistical atlas of the hippocampal formation at the subregion level using ultra-high resolution, ex vivo MRI. Fifteen autopsy samples were scanned at 0.13 mm isotropic resolution (on average) using customized hardware. The images were manually segmented into 13 different hippocampal substructures using a protocol specifically designed for this study; precise delineations were made possible by the extraordinary resolution of the scans. In addition to the subregions, manual annotations for neighboring structures (e.g., amygdala, cortex) were obtained from a separate dataset of in vivo, T1-weighted MRI scans of the whole brain (1mm resolution). The manual labels from the in vivo and ex vivo data were combined into a single computational atlas of the hippocampal formation with a novel atlas building algorithm based on Bayesian inference. The resulting atlas can be used to automatically segment the hippocampal subregions in structural MRI images, using an algorithm that can analyze multimodal data and adapt to variations in MRI contrast due to differences in acquisition hardware or pulse sequences. The applicability of the atlas, which we are releasing as part of FreeSurfer (version 6.0), is demonstrated with experiments on three different publicly available datasets with different types of MRI contrast. The results show that the atlas and companion segmentation method: 1) can segment T1 and T2 images, as well as their combination, 2) replicate findings on mild cognitive impairment based on high-resolution T2 data, and 3) can discriminate between Alzheimer's disease subjects and elderly controls with 88% accuracy in standard resolution (1mm) T1 data, significantly outperforming the atlas in FreeSurfer version 5.3 (86% accuracy) and classification based on whole hippocampal volume (82% accuracy). Copyright © 2015. Published by Elsevier Inc.

Different methods for anatomical targeting.

PubMed

Iacopino, D G; Conti, A; Angileri, F F; Tomasello, F

2003-03-01

Several procedures are used in the different neurosurgical centers in order to perform stereotactic surgery for movement disorders. At the moment no procedure can really be considered superior to the other. We contribute with our experience of targeting method. Ten patients were selected, in accordance to the guidelines for the treatment of Parkinson disease, and operated by several methods including pallidotomy, bilateral insertion of chronic deep brain electrodes within the internal pallidum and in the subthalamic nucleus (18 procedures). in each patient an MR scan was performed the day before surgery. Scans were performed axially parallel to the intercommissural line. The operating day a contrast CT scan was performed under stereotactic conditions. after digitalization of the MRI images, it was possible to visualize the surgical target and to relate it to parenchimal and vascular anatomic structures readable at the CT examination. The CT scan obtained was confronted with the MR previously performed, the geometrical relation between the different parenchimal and vascular structures and the selected targets were obtained. Stereotactic coordinates were obtained on the CT examination. It was possible to calculate the position of the subthalamic nucleus and of the internal pallidum on the CT scan, not only relating to the intercommissural line, but considering also the neurovascular structures displayed both on the MRI and the CT scans. The technique that our group presents consist in an integration between information derived from the CT and the MR techniques, so that we can benefit from the advantages of both methods and overcome the disadvantages.

Magnetic resonance imaging and computerized tomography in malignant external otitis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gherini, S.G.; Brackmann, D.E.; Bradley, W.G.

1986-05-01

In malignant external otitis (MEO), determining the anatomic extent of disease and evaluating the physiologic response to therapy remain a problem. Magnetic resonance imaging (MRI) has recently become available in limited clinical settings. Four patients with MEO were evaluated using MRI, computerized tomography (CT), technetium-99 (Tc-99) bone scanning, and gallium-67 citrate (Ga-67 citrate) scanning. MRI is superior to CT, Tc-99 bone scanning, and Ga-67 citrate scanning in evaluating the anatomic extent of soft tissue changes in MEO. MRI alone cannot be relied upon to determine the physiologic response to therapy. MRI can, however, serve as a valuable guide to themore » interpretation of Tc-99 bone and Ga-67 citrate scans, and in this respect, MRI is extremely useful in the treatment of MEO.« less

Magnetic resonance imaging in stress fractures and shin splints.

PubMed

Aoki, Yoshimitsu; Yasuda, Kazunori; Tohyama, Harukazu; Ito, Hirokazu; Minami, Akio

2004-04-01

The purpose of the current study was to determine whether stress fractures and shin splints could be discriminated with MRI in the early phase. Twenty-two athletes, who had pain in the middle or distal part of their leg during or after sports activity, were evaluated with radiographs and MRI scans. Stress fractures were diagnosed when consecutive radiographs showed local periosteal reaction or a fracture line, and shin splints were diagnosed in all the other cases. In all eight patients with stress fractures, an abnormally wide high signal in the localized bone marrow was the most detectable in the coronal fat-suppressed MRI scan. In 11 patients with shin splints, the coronal fat-suppressed MRI scans showed a linear abnormally high signal along the medial posterior surface of the tibia, and in seven patients with shin splints, the MRI scans showed a linear abnormally high signal along the medial bone marrow. No MRI scans of shin splints showed an abnormally wide high signal in the bone marrow as observed on MRI scans of stress fractures. This study showed that fat-suppressed MRI is useful for discrimination between stress fracture and shin splints before radiographs show a detectable periosteal reaction in the tibia.

Brain and Language.

ERIC Educational Resources Information Center

Damasio, Antonio R., Damasio, Hanna

1992-01-01

Discusses the advances made in understanding the brain structures responsible for language. Presents findings made using magnetic resonance imaging (MRI) and positron emission tomographic (PET) scans to study brain activity. These findings map the structures in the brain that manipulate concepts and those that turn concepts into words. (MCO)

Methods for Acquiring Structural MRI Data in Very Young Children with Autism without the Use of Sedation

ERIC Educational Resources Information Center

Nordahl, Christine Wu; Simon, Tony J.; Zierhut, Cynthia; Solomon, Marjorie; Rogers, Sally J.; Amaral, David G.

2008-01-01

We describe a protocol with which we achieved a 93% success rate in acquiring high quality MRI scans without the use of sedation in 2.5-4.5 year old children with autism, developmental delays, and typical development. Our main strategy was to conduct MRIs during natural nocturnal sleep in the evenings after the child's normal bedtime.…

Corpus Callosum Area and Brain Volume in Autism Spectrum Disorder: Quantitative Analysis of Structural MRI from the ABIDE Database

ERIC Educational Resources Information Center

Kucharsky Hiess, R.; Alter, R.; Sojoudi, S.; Ardekani, B. A.; Kuzniecky, R.; Pardoe, H. R.

2015-01-01

Reduced corpus callosum area and increased brain volume are two commonly reported findings in autism spectrum disorder (ASD). We investigated these two correlates in ASD and healthy controls using T1-weighted MRI scans from the Autism Brain Imaging Data Exchange (ABIDE). Automated methods were used to segment the corpus callosum and intracranial…

Positive parenting predicts the development of adolescent brain structure: a longitudinal study.

PubMed

Whittle, Sarah; Simmons, Julian G; Dennison, Meg; Vijayakumar, Nandita; Schwartz, Orli; Yap, Marie B H; Sheeber, Lisa; Allen, Nicholas B

2014-04-01

Little work has been conducted that examines the effects of positive environmental experiences on brain development to date. The aim of this study was to prospectively investigate the effects of positive (warm and supportive) maternal behavior on structural brain development during adolescence, using longitudinal structural MRI. Participants were 188 (92 female) adolescents, who were part of a longitudinal adolescent development study that involved mother-adolescent interactions and MRI scans at approximately 12 years old, and follow-up MRI scans approximately 4 years later. FreeSurfer software was used to estimate the volume of limbic-striatal regions (amygdala, hippocampus, caudate, putamen, pallidum, and nucleus accumbens) and the thickness of prefrontal regions (anterior cingulate and orbitofrontal cortices) across both time points. Higher frequency of positive maternal behavior during the interactions predicted attenuated volumetric growth in the right amygdala, and accelerated cortical thinning in the right anterior cingulate (males only) and left and right orbitofrontal cortices, between baseline and follow up. These results have implications for understanding the biological mediators of risk and protective factors for mental disorders that have onset during adolescence. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

The functional magnetic resonance imaging (fMRI) procedure as experienced by healthy participants and stroke patients--a pilot study.

PubMed

Szameitat, André J; Shen, Shan; Sterr, Annette

2009-07-31

An important aspect in functional imaging research employing magnetic resonance imaging (MRI) is how participants perceive the MRI scanning itself. For instance, the knowledge of how (un)comfortable MRI scanning is perceived may help institutional review boards (IRBs) or ethics committees to decide on the approval of a study, or researchers to design their experiments. We provide empirical data from our lab gained from 70 neurologically healthy mainly student subjects and from 22 mainly elderly patients suffering from motor deficits after brain damage. All participants took part in various basic research fMRI studies using a 3T MRI scanner. Directly after the scanning, all participants completed a questionnaire assessing their experience with the fMRI procedure. 87.2% of the healthy subjects and 77.3% of the patients rated the MRI procedure as acceptable to comfortable. In healthy subjects, males found the procedure more comfortable, while the opposite was true for patients. 12.1% of healthy subjects considered scanning durations between 30 and 60 min as too long, while no patient considered their 30 min scanning interval as too long. 93.4% of the healthy subjects would like to participate in an fMRI study again, with a significantly lower rate for the subjects who considered the scanning as too long. Further factors, such as inclusion of a diffusion tensor imaging (DTI) scan, age, and study duration had no effect on the questionnaire responses. Of the few negative comments, the main issues were noise, the restriction to keep still for the whole time, and occasional feelings of dizziness. MRI scanning in the basic research setting is an acceptable procedure for elderly and patient participants as well as young healthy subjects.

The functional magnetic resonance imaging (fMRI) procedure as experienced by healthy participants and stroke patients – A pilot study

PubMed Central

2009-01-01

Background An important aspect in functional imaging research employing magnetic resonance imaging (MRI) is how participants perceive the MRI scanning itself. For instance, the knowledge of how (un)comfortable MRI scanning is perceived may help institutional review boards (IRBs) or ethics committees to decide on the approval of a study, or researchers to design their experiments. Methods We provide empirical data from our lab gained from 70 neurologically healthy mainly student subjects and from 22 mainly elderly patients suffering from motor deficits after brain damage. All participants took part in various basic research fMRI studies using a 3T MRI scanner. Directly after the scanning, all participants completed a questionnaire assessing their experience with the fMRI procedure. Results 87.2% of the healthy subjects and 77.3% of the patients rated the MRI procedure as acceptable to comfortable. In healthy subjects, males found the procedure more comfortable, while the opposite was true for patients. 12.1% of healthy subjects considered scanning durations between 30 and 60 min as too long, while no patient considered their 30 min scanning interval as too long. 93.4% of the healthy subjects would like to participate in an fMRI study again, with a significantly lower rate for the subjects who considered the scanning as too long. Further factors, such as inclusion of a diffusion tensor imaging (DTI) scan, age, and study duration had no effect on the questionnaire responses. Of the few negative comments, the main issues were noise, the restriction to keep still for the whole time, and occasional feelings of dizziness. Conclusion MRI scanning in the basic research setting is an acceptable procedure for elderly and patient participants as well as young healthy subjects. PMID:19646238

Clinical utility of MRI and SPECT in the diagnosis of cognitive impairment referred to memory clinic.

PubMed

Guinane, John; Ng, Boon Lung

2018-05-01

ABSTRACTBackground:Despite of their limited availability and potential for significant variation between and within each modality, this is the first study to prospectively measure the clinical utility of MRI and/or SPECT brain scanning in addition to the routine diagnostic workup of patients presenting to memory clinic. A single center study was conducted over a convenience of 12-month sampling period. For each patient referred for MRI and/or SPECT scanning, the primary geriatrician or psychogeriatrician was asked to assign an initial diagnosis. The initial diagnosis was then compared with the final consensus diagnosis after any scans or neuropsychology testing had been completed. During the 12-month study period, 66 patients (26%) were referred for scans out of a total of 253 patients included in the study. There were 16/44 (36%) positive MRI outcomes and 13/35 (37%) positive SPECT outcomes. The diagnosis changed consistent with the MRI scan findings in 11/44 (25%) and changed consistent with the SPECT scan findings in 9/35 (26%). Potentially reversible pathology was identified in a single patient, 1/50 (2%), via an MRI scan that suggested normal pressure hydrocephalus. The number needed to test for one positive outcome was 3.8 (95% CI 2.0-23.3), 6.0 (95% CI NA), and 1.7 (95% CI 1.3-2.5) for MRI only, SPECT only, and MRI and SPECT together, respectively. The clinical utility of MRI and/or SPECT scanning in this study may be broadly superior to the available international evidence, and further research is needed to identify predictors of positive scan outcomes.

Multi-atlas segmentation of subcortical brain structures via the AutoSeg software pipeline

PubMed Central

Wang, Jiahui; Vachet, Clement; Rumple, Ashley; Gouttard, Sylvain; Ouziel, Clémentine; Perrot, Emilie; Du, Guangwei; Huang, Xuemei; Gerig, Guido; Styner, Martin

2014-01-01

Automated segmenting and labeling of individual brain anatomical regions, in MRI are challenging, due to the issue of individual structural variability. Although atlas-based segmentation has shown its potential for both tissue and structure segmentation, due to the inherent natural variability as well as disease-related changes in MR appearance, a single atlas image is often inappropriate to represent the full population of datasets processed in a given neuroimaging study. As an alternative for the case of single atlas segmentation, the use of multiple atlases alongside label fusion techniques has been introduced using a set of individual “atlases” that encompasses the expected variability in the studied population. In our study, we proposed a multi-atlas segmentation scheme with a novel graph-based atlas selection technique. We first paired and co-registered all atlases and the subject MR scans. A directed graph with edge weights based on intensity and shape similarity between all MR scans is then computed. The set of neighboring templates is selected via clustering of the graph. Finally, weighted majority voting is employed to create the final segmentation over the selected atlases. This multi-atlas segmentation scheme is used to extend a single-atlas-based segmentation toolkit entitled AutoSeg, which is an open-source, extensible C++ based software pipeline employing BatchMake for its pipeline scripting, developed at the Neuro Image Research and Analysis Laboratories of the University of North Carolina at Chapel Hill. AutoSeg performs N4 intensity inhomogeneity correction, rigid registration to a common template space, automated brain tissue classification based skull-stripping, and the multi-atlas segmentation. The multi-atlas-based AutoSeg has been evaluated on subcortical structure segmentation with a testing dataset of 20 adult brain MRI scans and 15 atlas MRI scans. The AutoSeg achieved mean Dice coefficients of 81.73% for the subcortical structures. PMID:24567717

Magnetic Resonance Imaging in Nondependent Pacemaker Patients with Pacemakers and Defibrillators with a Nearly Depleted Battery.

PubMed

Okamura, Hideo; Padmanabhan, Deepak; Watson, Robert E; Dalzell, Connie; Acker, Nancy; Jondal, Mary; Romme, Abby L; Cha, Yong-Mei; Asirvatham, Samuel J; Felmlee, Joel P; Friedman, Paul A

2017-05-01

Magnetic resonance imaging (MRI) in patients with non-MRI-conditional cardiac implantable electronic devices (CIEDs) has been shown to be safe when performed under closely monitored protocols. However, the safety of MRI in patients with devices with a nearly depleted battery has not been reported. Prospective data were collected between January 2008 and May 2015 in patients with non-MRI-conditional CIEDs undergoing clinically indicated MRI under institutional protocol. Patients who were pacemaker dependent were excluded. Patients whose devices were at elective replacement indicator (ERI) at the time of MRI or close to ERI (ERI or replacement for battery depletion within 3 months of scan) were identified through database review and analyzed for clinical events. MRI scans (n = 569) were performed in 442 patients. Of these, we identified 13 scans performed with a nearly depleted battery in nine patients. All scans with implantable cardioverter defibrillators (ICDs, n = 9) were uneventful. However, two scans with pacemakers close to ERI resulted in a power-on-reset (PoR) event. One scan with a pacemaker close to ERI that was programmed to DOO mode reached ERI during MRI and automatically changed to VVI mode. Additionally, one scan with a pacemaker at ERI did not allow programming. All pacemakers with events were implanted before 2005. Patients with pacemakers and ICDs with a nearly depleted battery can safely undergo MRI when patients are not pacemaker dependent. Attention should be paid because old devices can result in PoR or ERI during MRI, which may lead to oversensing and inhibition of pacing. © 2017 Wiley Periodicals, Inc.

Rotator cuff disorders: How to write a surgically relevant magnetic resonance imaging report?

PubMed Central

Tawfik, Ahmed M; El-Morsy, Ahmad; Badran, Mohamed Aboelnour

2014-01-01

Evaluation of rotator cuff is a common indication for magnetic resonance imaging (MRI) scanning of the shoulder. Conventional MRI is the most commonly used technique, while magnetic resonance (MR) arthrography is reserved for certain cases. Rotator cuff disorders are thought to be caused by a combination of internal and external mechanisms. A well-structured MRI report should comment on the relevant anatomic structures including the acromial type and orientation, the presence of os acromiale, acromio-clavicular degenerative spurs and fluid in the subacromial subdeltoid bursa. In addition, specific injuries of the rotator cuff tendons and the condition of the long head of biceps should be accurately reported. The size and extent of tendon tears, tendon retraction and fatty degeneration or atrophy of the muscles are all essential components of a surgically relevant MRI report. PMID:24976930

SU-E-J-264: Using Magnetic Resonance Imaging-Derived Features to Quantify Radiotherapy-Induced Normal Tissue Morbidity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thor, M; Tyagi, N; Deasy, J

2015-06-15

Purpose: The aim of this study was to explore the use of Magnetic Resonance Imaging (MRI)-derived features as indicators of Radiotherapy (RT)-induced normal tissue morbidity. We also investigate the relationship between these features and RT dose in four critical structures. Methods: We demonstrate our approach for four patients treated with RT for base of tongue cancer in 2005–2007. For each patient, two MRI scans (T1-weighted pre (T1pre) and post (T1post) gadolinium contrast-enhancement) were acquired within the first six months after RT. The assessed morbidity endpoint observed in 2/4 patients was Grade 2+ CTCAEv.3 trismus. Four ipsilateral masticatory-related structures (masseter, lateralmore » and medial pterygoid, and the temporal muscles) were delineated on both T1pre and T1post and these scans were co-registered to the treatment planning CT using a deformable demons algorithm. For each structure, the maximum and mean RT dose, and six MRI-derived features (the second order texture features entropy and homogeneity, and the first order mean, median, kurtosis, and skewness) were extracted and compared structure-wise between patients with and without trismus. All MRI-derived features were calculated as the difference between T1pre and T1post, ΔS. Results: For 5/6 features and all structures, ΔS diverged between trismus and non-trismus patients particularly for the masseter, lateral pterygoid, and temporal muscles using the kurtosis feature (−0.2 vs. 6.4 for lateral pterygoid). Both the maximum and mean RT dose in all four muscles were higher amongst the trismus patients (with the maximum dose being up to 25 Gy higher). Conclusion: Using MRI-derived features to quantify RT-induced normal tissue complications is feasible. We showed that several features are different between patients with and without morbidity and that the RT dose in all investigated structures are higher amongst patients with morbidity. MRI-derived features, therefore, has the potential to improve predictions of normal tissue morbidity.« less

Advanced magnetic resonance imaging of neurodegenerative diseases.

PubMed

Agosta, Federica; Galantucci, Sebastiano; Filippi, Massimo

2017-01-01

Magnetic resonance imaging (MRI) is playing an increasingly important role in the study of neurodegenerative diseases, delineating the structural and functional alterations determined by these conditions. Advanced MRI techniques are of special interest for their potential to characterize the signature of each neurodegenerative condition and aid both the diagnostic process and the monitoring of disease progression. This aspect will become crucial when disease-modifying (personalized) therapies will be established. MRI techniques are very diverse and go from the visual inspection of MRI scans to more complex approaches, such as manual and automatic volume measurements, diffusion tensor MRI, and functional MRI. All these techniques allow us to investigate the different features of neurodegeneration. In this review, we summarize the most recent advances concerning the use of MRI in some of the most important neurodegenerative conditions, putting an emphasis on the advanced techniques.

High success rates of sedation-free brain MRI scanning in young children using simple subject preparation protocols with and without a commercial mock scanner–the Diabetes Research in Children Network (DirecNet) experience

PubMed Central

Barnea-Goraly, Naama; Weinzimer, Stuart A.; Mauras, Nelly; Beck, Roy W.; Marzelli, Matt J.; Mazaika, Paul K.; Aye, Tandy; White, Neil H.; Tsalikian, Eva; Fox, Larry; Kollman, Craig; Cheng, Peiyao; Reiss, Allan L.

2013-01-01

Background The ability to lie still in an MRI scanner is essential for obtaining usable image data. To reduce motion, young children are often sedated, adding significant cost and risk. Objective We assessed the feasibility of using a simple and affordable behavioral desensitization program to yield high-quality brain MRI scans in sedation-free children. Materials and methods 222 children (4–9.9 years), 147 with type 1 diabetes and 75 age-matched non-diabetic controls, participated in a multi-site study focused on effects of type 1 diabetes on the developing brain. T1-weighted and diffusion-weighted imaging (DWI) MRI scans were performed. All children underwent behavioral training and practice MRI sessions using either a commercial MRI simulator or an inexpensive mock scanner consisting of a toy tunnel, vibrating mat, and video player to simulate the sounds and feel of the MRI scanner. Results 205 children (92.3%), mean age 7±1.7 years had high-quality T1-W scans and 174 (78.4%) had high-quality diffusion-weighted scans after the first scan session. With a second scan session, success rates were 100% and 92.5% for T1-and diffusion-weighted scans, respectively. Success rates did not differ between children with type 1 diabetes and children without diabetes, or between centers using a commercial MRI scan simulator and those using the inexpensive mock scanner. Conclusion Behavioral training can lead to a high success rate for obtaining high-quality T1-and diffusion-weighted brain images from a young population without sedation. PMID:24096802

Effect of pulse sequence parameter selection on signal strength in positive-contrast MRI markers for MRI-based prostate postimplant assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, Tze Yee

Purpose: For postimplant dosimetric assessment, computed tomography (CT) is commonly used to identify prostate brachytherapy seeds, at the expense of accurate anatomical contouring. Magnetic resonance imaging (MRI) is superior to CT for anatomical delineation, but identification of the negative-contrast seeds is challenging. Positive-contrast MRI markers were proposed to replace spacers to assist seed localization on MRI images. Visualization of these markers under varying scan parameters was investigated. Methods: To simulate a clinical scenario, a prostate phantom was implanted with 66 markers and 86 seeds, and imaged on a 3.0T MRI scanner using a 3D fast radiofrequency-spoiled gradient recalled echo acquisitionmore » with various combinations of scan parameters. Scan parameters, including flip angle, number of excitations, bandwidth, field-of-view, slice thickness, and encoding steps were systematically varied to study their effects on signal, noise, scan time, image resolution, and artifacts. Results: The effects of pulse sequence parameter selection on the marker signal strength and image noise were characterized. The authors also examined the tradeoff between signal-to-noise ratio, scan time, and image artifacts, such as the wraparound artifact, susceptibility artifact, chemical shift artifact, and partial volume averaging artifact. Given reasonable scan time and managable artifacts, the authors recommended scan parameter combinations that can provide robust visualization of the MRI markers. Conclusions: The recommended MRI pulse sequence protocol allows for consistent visualization of the markers to assist seed localization, potentially enabling MRI-only prostate postimplant dosimetry.« less

Hypothermic Cooling Measured by Thermal Magnetic Resonance Imaging; Feasibility and Implications for Virtual Imaging in the Urogenital Pelvis.

PubMed

Skarecky, Douglas; Yu, Hon; Linehan, Jennifer; Morales, Blanca; Su, Min-Ying; Fwu, Peter; Ahlering, Thomas

2017-10-01

To study the combination of thermal magnetic resonance imaging (MRI) and novel hypothermic cooling, via an endorectal cooling balloon (ECB), to assess the effective dispersion and temperature drop in pelvic tissue to potentially reduce inflammatory cascade in surgical applications. Three male subjects, before undergoing robot-assisted radical prostatectomy, were cooled via an ECB, rendered MRI compatible for patient safety before ECB hypothermia. MRI studies were performed using a 3T scanner and included T2-weighted anatomic scan for the pelvic structures, followed by a temperature mapping scan. The sequence was performed repeatedly during the cooling experiment, whereas the phase data were collected using an integrated MR-high-intensity focused ultrasound workstation in real time. Pelvic cooling was instituted with a cooling console located outside the MRI magnet room. The feasibility of pelvic cooling measured a temperature drop of the ECB of 20-25 degrees in real time was achieved after an initial time delay of 10-15 seconds for the ECB to cool. The thermal MRI anatomic images of the prostate and neurovascular bundle demonstrate cooling at this interface to be 10-15 degrees, and also that cooling extends into the prostate itself ~5 degrees, and disperses into the pelvic region as well. An MRI-compatible ECB coupled with thermal MRI is a feasible method to assess effective hypothermic diffusion and saturation to pelvic structures. By inference, hypothermia-induced rectal cooling could potentially reduce inflammation, scarring, and fistula in radical prostatectomy, as well as other urologic tissue procedures of high-intensity focused ultrasound, external beam radiation therapy, radioactive seed implants, transurethral microwave therapy, and transurethral resection of the prostate. Copyright © 2017 Elsevier Inc. All rights reserved.

No effects of MRI scan on male reproduction hormones.

PubMed

Møllerløkken, Ole J; Moen, Bente E; Baste, Valborg; Magerøy, Nils; Oftedal, Gunnhild; Neto, Emanuel; Ersland, Lars; Bjørge, Line; Torjesen, Peter A; Mild, Kjell Hansson

2012-08-01

Magnetic resonance imaging (MRI) is increasing around the world and the possible adverse effects on reproductive health of electromagnetic fields (EMFs) in MRI are not previously studied. A prospective randomized balanced cross-over study using a head scan in real MRI with whole-body transmitting coil and sham MRI among 24 healthy male volunteers was conducted. Serum-blood samples of inhibin B, testosterone, prolactine, thyreotropine, luteinizing hormone, follicle stimulating hormone, sex-hormone binding globuline and estradiol were taken before and after the different scans. Neither immediately after, nor after 11 days were there seen any differences in the hormone levels comparing real and sham MRI. The lack of effects of EMF on male reproductive hormones should be reassuring to the public and especially for men examined in MRI. Adverse effects on other endpoints than male reproduction or possible chronic effect of multiple MRI scans have not been investigated in this study. Copyright © 2012 Elsevier Inc. All rights reserved.

Multi organ assessment of Compensated Cirrhosis Patients using quantitative Magnetic Resonance Imaging.

PubMed

Bradley, Christopher R; Cox, Eleanor F; Scott, Robert A; James, Martin W; Kaye, Phillip; Aithal, Guruprasad P; Francis, Susan T; Guha, Indra Neil

2018-06-07

Advancing liver disease results in deleterious changes in a number of critical organs. The ability to measure structure, blood flow and tissue perfusion within multiple organs in a single scan has implications for determining the balance of benefit versus harm for therapies. Our aim was to establish the feasibility of Magnetic Resonance Imaging to assess changes in compensated cirrhosis (CC), and relate this to disease severity and future liver related outcomes (LROs). 60 CC patients, 40 healthy volunteers and 7 decompensated cirrhotics were recruited. In a single scan session, MRI measures comprised phase-contrast MRI vessel blood flow, arterial spin labelling tissue perfusion, T 1 longitudinal relaxation time and volume assessment of liver, spleen and kidneys, heart rate and cardiac index. We explore MRI parameters with disease severity and differences in baseline MRI parameters in those 11 (18%) of CC patients who had future LROs. In the liver compositional changes were reflected by increased T 1 in progressive disease (p<0.001) and an increase in liver volume in CC (p=0.006), with associated progressive reduction in liver (p < 0.001) and splenic (p<0.001) perfusion. A significant reduction in renal cortex T 1 and increase in cardiac index and superior mesenteric arterial (SMA) blood flow was seen with increasing disease severity. Baseline liver T 1 (p=0.01) and perfusion (p< 0.01), and renal cortex T 1 (p<0.01) were significantly different in CC patients who subsequently developed negative LROs. MRI allows the contemporaneous assessment of organs in liver cirrhosis in a single scan without the requirement of contrast agent. MRI parameters of liver T 1, renal T 1, hepatic and splenic perfusion, and SMA blood flow were related to risk of LROs. This study assesses the changes to structure, blood flow and perfusion that occur in the key organs (liver, spleen and kidney) associated with severe liver disease (compensated cirrhosis). Those MRI measures which change with disease severity and are related to negative liver related clinical outcomes are described. Copyright © 2018 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

[Comparison of the Arthroscopic Finding in the Knee Joint and the MRI - Retrospective Study].

PubMed

Šimeček, K; Látal, P; Duda, J; Šimeček, M

2017-01-01

PURPOSE OF THE STUDY Our retrospective study presents the comparison of the preoperative magnetic resonance imaging of the knee joint - MRI - and the arthroscopic finding - ASC. Its aim is to find out how a positive or a negative finding of MRI corresponds with the operative finding and how much the experience of radiologist contributes to the conformity. MATERIAL AND METHODS The MRI findings of knee joints treated surgically at two departments in 2013 and 2014 were assessed. The MRI was performed in a total of 470 patients who subsequently underwent an arthroscopic surgery. A conformity or a non-conformity in anterior, posterior horn and complete rupture of both menisci and in partial or complete tear of anterior cruciate ligament - LCA was searched for. The sensitivity, specificity and accuracy of MRI were established. The difference between experienced and less experienced radiologists was evaluated. The analysis of the radiology report, surgical protocol of ASC and medical history in the documentation was performed. The cartilage was not subject to evaluation. The finding of Grade 1 meniscus tear on MRI was evaluated as negative. Grade 2 and Grade 3 were evaluated as positive. RESULTS Comparison of the preoperative MRI and the arthroscopic finding 1. The group with MRI reported 3 % of diagnostic arthroscopies. The control group without MRI (551 ASC) reported 15 % diagnostic arthroscopies. 2. Low sensitivity of MRI (0.67) in negative findings of ASC. It concerned 7 cases in which a pathological finding was identified on a MRI scan, but not by ASC. In two cases the repeated arthroscopy confirmed that a pathology inside the knee joint was overlooked by the arthroscopist. In the remaining five cases, the clinical finding improved without a repeated surgery. 3. High sensitivity of MRI is shown in the most frequent finding - posterior horn of medial meniscus (0.94). 4. Lower sensitivity (0.76) in partial and (0.83) in complete ACL tear. It increases to 0.93 if partial and complete tear are put together. Both MRI and ASC detect the pathology of ligament, but do not agree in terms of terminology. 5. Lower sensitivity (0.78) was seen in posterior horn of lateral meniscus, most likely due to its complicated anatomy. 6. Specificity of complete tear of medial meniscus tear is 0.99. Lower specificity in the posterior horn of medial meniscus (0.81) shows a higher number of positive MRI findings in negative ASC findings. Some posterior horn tear can be overlooked by an inexperienced surgeon. The MRD findings need to be studied. 7. High specificity (0.99) was described in negative findings. In three cases only, the surgeon discovered a pathological finding, not revealed by MRI scan. It always concerned a tear within the posterior horn of the medial meniscus. 8. Specificity (0.88, 0.93 or 0.86, respectively) in partial, complete and all ACL damages in total. 9. We concluded that contributing to the degree of agreement between MRI and ASC is also the experience of a radiologist. The most experienced radiologist evaluated 190 of 470 MRI scans, the remaining twelve radiologists assessed 280 scans. The posterior horn of the medial meniscus - sensitivity or specificity evaluated by an experienced radiologist (0.98 and 0.88, respectively) and inexperienced radiologist (0.91 and 0.79). The specificity and sensitivity in complete ACL tears - by experienced radiologist (0.91 and 0.94, respectively) and inexperienced radiologist (0.81 and 0.90, respectively). The test accuracy of the experienced radiologist in evaluating the most frequent injuries of soft knee structures was by 9-10 % higher than of the inexperienced radiologist. DISCUSSION The results obtained by the other authors show that the sensitivity and specificity range from 0.6 to 0.9. They agree that the MRI is unsuitable for assessing the cartilage. We confirm that the results are worse when evaluating the posterior horn of the lateral meniscus. We have also proven that the radiologist s experience does play an important role. It can be the reason for a high degree of difference between the results of various authors. Some of them give preference to a clinical examination or a diagnostic arthroscopy instead of the MRI. At our department, MRI is indicated if we are convinced it can help with the indication or where it will suggest what to focus on during the surgery. CONCLUSIONS A preoperative MRI scan can prevent an unnecessary arthroscopy. It displays structures to the surgeon which shall be reviewed in detail during the surgery. We recommend paying attention to Grade 2 MRI findings, positive MRI findings on the posterior horn of medial meniscus and to MRI findings on partial ACL tears. Such menisci and ligaments shall be carefully reviewed. Clinical preoperative examination and cooperation between the surgeon, the "arthroscopist", and the radiologist is essential. The experience of the radiologist also plays a role when evaluating the MRI scan. We have introduced MRI ward rounds. Key words: MRI, knee joint, knee arthroscopy, sensitivity, specificity, accuracy.

Neonatal physiological correlates of near-term brain development on MRI and DTI in very-low-birth-weight preterm infants.

PubMed

Rose, Jessica; Vassar, Rachel; Cahill-Rowley, Katelyn; Stecher Guzman, Ximena; Hintz, Susan R; Stevenson, David K; Barnea-Goraly, Naama

2014-01-01

Structural brain abnormalities identified at near-term age have been recognized as potential predictors of neurodevelopment in children born preterm. The aim of this study was to examine the relationship between neonatal physiological risk factors and early brain structure in very-low-birth-weight (VLBW) preterm infants using structural MRI and diffusion tensor imaging (DTI) at near-term age. Structural brain MRI, diffusion-weighted scans, and neonatal physiological risk factors were analyzed in a cross-sectional sample of 102 VLBW preterm infants (BW ≤ 1500 g, gestational age (GA) ≤ 32 weeks), who were admitted to the Lucile Packard Children's Hospital, Stanford NICU and recruited to participate prior to routine near-term brain MRI conducted at 36.6 ± 1.8 weeks postmenstrual age (PMA) from 2010 to 2011; 66/102 also underwent a diffusion-weighted scan. Brain abnormalities were assessed qualitatively on structural MRI, and white matter (WM) microstructure was analyzed quantitatively on DTI in six subcortical regions defined by DiffeoMap neonatal brain atlas. Specific regions of interest included the genu and splenium of the corpus callosum, anterior and posterior limbs of the internal capsule, the thalamus, and the globus pallidus. Regional fractional anisotropy (FA) and mean diffusivity (MD) were calculated using DTI data and examined in relation to neonatal physiological risk factors including gestational age (GA), bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), retinopathy of prematurity (ROP), and sepsis, as well as serum levels of C-reactive protein (CRP), glucose, albumin, and total bilirubin. Brain abnormalities were observed on structural MRI in 38/102 infants including 35% of females and 40% of males. Infants with brain abnormalities observed on MRI had higher incidence of BPD (42% vs. 25%) and sepsis (21% vs. 6%) and higher mean and peak serum CRP levels, respectively, (0.64 vs. 0.34 mg/dL, p = .008; 1.57 vs. 0.67 mg/dL, p= .006) compared to those without. The number of signal abnormalities observed on structural MRI correlated to mean and peak CRP (rho = .316, p = .002; rho = .318, p= .002). The number of signal abnormalities observed on MRI correlated with thalamus MD (left: r= .382, p= .002; right: r= .400, p= .001), controlling for PMA-at-scan. Thalamus WM microstructure demonstrated the strongest associations with neonatal risk factors. Higher thalamus MD on the left and right, respectively, was associated with lower GA (r = -.322, p = .009; r= -.381, p= .002), lower mean albumin (r = -.276, p= .029; r= -.385, p= .002), and lower mean bilirubin (r = -.293, p= .020; r= -.337 p= .007). Results suggest that at near-term age, thalamus WM microstructure may be particularly vulnerable to certain neonatal risk factors. Interactions between albumin, bilirubin, phototherapy, and brain development warrant further investigation. Identification of physiological risk factors associated with selective vulnerability of certain brain regions at near-term age may clarify the etiology of neurodevelopmental impairment and inform neuroprotective treatment for VLBW preterm infants.

Development of Magnetic Resonance Imaging Biomarkers for Traumatic Brain Injury

DTIC Science & Technology

2012-07-01

months) stages after injury, the patients will be brought back to repeat both the MRI scans and neurocognitive evaluations. Age/gender/ education ...J.H., 2010. On the contribution of deoxy- hemoglobin to MRI gray-white matter phase contrast at high field. Neuro- image 49, 193–198. Li, C., Langham...provides physical and structural support of neuronal and glial cells. From a physiological point of view, the blood flow provides nutritional sup- port

Magnetic Resonance Safety

PubMed Central

Sammet, Steffen

2016-01-01

Magnetic Resonance Imaging (MRI) has a superior soft-tissue contrast compared to other radiological imaging modalities and its physiological and functional applications have led to a significant increase in MRI scans worldwide. A comprehensive MRI safety training to protect patients and other healthcare workers from potential bio-effects and risks of the magnetic fields in an MRI suite is therefore essential. The knowledge of the purpose of safety zones in an MRI suite as well as MRI appropriateness criteria is important for all healthcare professionals who will work in the MRI environment or refer patients for MRI scans. The purpose of this article is to give an overview of current magnetic resonance safety guidelines and discuss the safety risks of magnetic fields in an MRI suite including forces and torque of ferromagnetic objects, tissue heating, peripheral nerve stimulation and hearing damages. MRI safety and compatibility of implanted devices, MRI scans during pregnancy and the potential risks of MRI contrast agents will also be discussed and a comprehensive MRI safety training to avoid fatal accidents in an MRI suite will be presented. PMID:26940331

Incidental findings on MRI scans of patients presenting with audiovestibular symptoms.

PubMed

Papanikolaou, Vasileios; Khan, Mohammad H; Keogh, Ivan J

2010-06-07

The evaluation of patients presenting with audiovestibular symptoms usually includes MRI of the internal auditory meatus, the cerebellopontine angle and the brain. A significant percentage of these scans will present unexpected, incidental findings, which could have important clinical significance. To determine the frequency and clinical significance of incidental findings on MRI scans of patients with audiovestibular symptoms. A retrospective analysis of 200 serial MRI scans. Gender distribution: equal. Age range: 17-82 years. One-hundred and four scans (52%) were normal and 1 scan (0.5%) demonstrated a unilateral vestibular schwannoma. Ninety-five scans (47.5%) demonstrated incidental findings. Sixty-six of these (33%) were considered of ishaemic origin and did not require further action. Five (2.5%) scans demonstrated significant findings which warranted appropriate referral; Two Gliomas (1%), 2 cases of extensive White Matter Lesions (1%), 1 lipoma (0.5%). The remaining scans demonstrated various other findings. Investigation of patients with audiovestibular symptoms with MRI scans revealed incidental findings in a significant percentage (47.5%). The majority of these findings were benign warranting no further action and only 2.5% required further referral. It is the responsibility of the referring Otolaryngologist to be aware of these findings, to be able to assess their significance, to inform the patient and if needed to refer for further evaluation.

Amyloid positron emission tomography with (18)F-flutemetamol and structural magnetic resonance imaging in the classification of mild cognitive impairment and Alzheimer's disease.

PubMed

Duara, Ranjan; Loewenstein, David A; Shen, Qian; Barker, Warren; Potter, Elizabeth; Varon, Daniel; Heurlin, Kristen; Vandenberghe, Rik; Buckley, Christopher

2013-05-01

To evaluate the contributions of amyloid-positive (Am+) and medial temporal atrophy-positive (MTA+) scans to the diagnostic classification of prodromal and probable Alzheimer's disease (AD). (18)F-flutemetamol-labeled amyloid positron emission tomography (PET) and magnetic resonance imaging (MRI) were used to classify 10 young normal, 15 elderly normal, 20 amnestic mild cognitive impairment (aMCI), and 27 AD subjects. MTA+ status was determined using a cut point derived from a previous study, and Am+ status was determined using a conservative and liberal cut point. The rates of MRI scans with positive results among young normal, elderly normal, aMCI, and AD subjects were 0%, 20%, 75%, and 82%, respectively. Using conservative cut points, the rates of Am+ scans for these same groups of subjects were 0%, 7%, 50%, and 93%, respectively, with the aMCI group showing the largest discrepancy between Am+ and MTA+ scans. Among aMCI cases, 80% of Am+ subjects were also MTA+, and 70% of amyloid-negative (Am-) subjects were MTA+. The combination of amyloid PET and MTA data was additive, with an overall correct classification rate for aMCI of 86%, when a liberal cut point (standard uptake value ratio = 1.4) was used for amyloid positivity. (18)F-flutemetamol PET and structural MRI provided additive information in the diagnostic classification of aMCI subjects, suggesting an amyloid-independent neurodegenerative component among aMCI subjects in this sample. Copyright © 2013 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

Thermo-Acoustic Ultrasound for Detection of RF-Induced Device Lead Heating in MRI.

PubMed

Dixit, Neerav; Stang, Pascal P; Pauly, John M; Scott, Greig C

2018-02-01

Patients who have implanted medical devices with long conductive leads are often restricted from receiving MRI scans due to the danger of RF-induced heating near the lead tips. Phantom studies have shown that this heating varies significantly on a case-by-case basis, indicating that many patients with implanted devices can receive clinically useful MRI scans without harm. However, the difficulty of predicting RF-induced lead tip heating prior to scanning prevents numerous implant recipients from being scanned. Here, we demonstrate that thermo-acoustic ultrasound (TAUS) has the potential to be utilized for a pre-scan procedure assessing the risk of RF-induced lead tip heating in MRI. A system was developed to detect TAUS signals by four different TAUS acquisition methods. We then integrated this system with an MRI scanner and detected a peak in RF power absorption near the tip of a model lead when transmitting from the scanner's body coil. We also developed and experimentally validated simulations to characterize the thermo-acoustic signal generated near lead tips. These results indicate that TAUS is a promising method for assessing RF implant safety, and with further development, a TAUS pre-scan could allow many more patients to have access to MRI scans of significant clinical value.

Ventricular Geometry From Non-contrast Non-ECG-gated CT Scans: An Imaging Marker of Cardiopulmonary Disease in Smokers.

PubMed

Rahaghi, Farbod N; Vegas-Sanchez-Ferrero, Gonzalo; Minhas, Jasleen K; Come, Carolyn E; De La Bruere, Isaac; Wells, James M; González, Germán; Bhatt, Surya P; Fenster, Brett E; Diaz, Alejandro A; Kohli, Puja; Ross, James C; Lynch, David A; Dransfield, Mark T; Bowler, Russel P; Ledesma-Carbayo, Maria J; San José Estépar, Raúl; Washko, George R

2017-05-01

Imaging-based assessment of cardiovascular structure and function provides clinically relevant information in smokers. Non-cardiac-gated thoracic computed tomographic (CT) scanning is increasingly leveraged for clinical care and lung cancer screening. We sought to determine if more comprehensive measures of ventricular geometry could be obtained from CT using an atlas-based surface model of the heart. Subcohorts of 24 subjects with cardiac magnetic resonance imaging (MRI) and 262 subjects with echocardiography were identified from COPDGene, a longitudinal observational study of smokers. A surface model of the heart was manually initialized, and then automatically optimized to fit the epicardium for each CT. Estimates of right and left ventricular (RV and LV) volume and free-wall curvature were then calculated and compared to structural and functional metrics obtained from MRI and echocardiograms. CT measures of RV dimension and curvature correlated with similar measures obtained using MRI. RV and LV volume obtained from CT inversely correlated with echocardiogram-based estimates of RV systolic pressure using tricuspid regurgitation jet velocity and LV ejection fraction respectively. Patients with evidence of RV or LV dysfunction on echocardiogram had larger RV and LV dimensions on CT. Logistic regression models based on demographics and ventricular measures from CT had an area under the curve of >0.7 for the prediction of elevated right ventricular systolic pressure and ventricular failure. These data suggest that non-cardiac-gated, non-contrast-enhanced thoracic CT scanning may provide insight into cardiac structure and function in smokers. Copyright © 2017. Published by Elsevier Inc.

Utility of Magnetic Resonance Imaging for the Diagnosis of Appendicitis During Pregnancy: A Canadian Experience.

PubMed

Burns, Michael; Hague, Cameron J; Vos, Patrick; Tiwari, Pari; Wiseman, Sam M

2017-11-01

The objective of the study was to evaluate the performance of magnetic resonance imaging (MRI) for the diagnosis of appendicitis during pregnancy. We conducted a retrospective review of all MRI scans performed at our institution, between 2006 and 2012, for the evaluation of suspected appendicitis in pregnant women. Details of the MRI scans performed were obtained from the radiology information system as well as details of any ultrasounds carried out for the same indication. Clinical and pathological data were obtained by retrospective chart review. The study population comprised 63 patients, and 8 patients underwent a second MRI scan during the same pregnancy. A total of 71 MRI scans were reviewed. The appendix was identified on 40 scans (56.3%). Sensitivity of MRI was 75% and specificity was 100% for the diagnosis of appendicitis in pregnant women. When cases with right lower quadrant inflammatory fat stranding or focal fluid, without appendix visualization, were classified as positive for appendicitis, MRI sensitivity increased to 81.3% but specificity decreased to 96.4%. MRI is sensitive and highly specific for the diagnosis of appendicitis during pregnancy and should be considered as a first line imaging study for this clinical presentation. Copyright © 2017 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

Evaluation of an internet-based animated preparatory video for children undergoing non-sedated MRI.

PubMed

McGlashan, Hannah L; Dineen, Rob A; Szeszak, Sofia; Whitehouse, William P; Chow, Gabriel; Love, Andrew; Langmack, Gill; Wharrad, Heather

2018-05-10

We evaluate the value of an internet-based educational animated video designed to prepare children for MRI scans, and whether this video reduces scan-related anxiety in children with a neurological disorder, and healthy controls. Participants completed a pre- and post-scan questionnaire evaluating participant online viewing behaviour, understanding of the MRI procedure, anxiety regarding the MRI, impact of animation in preparing the child and whether the child's expectation of the MRI scan matched their experience. 21 children were recruited (12 healthy controls) ranging in age from 6.5 to 11.5 years. The animation was successfully accessed by participants on a range of digital devices and had high levels of approval. Children who viewed the animation had a good understanding of the MRI procedure and low anxiety levels prior to the scan, and reported that their expectations broadly matched the real-life MRI experience. Children reported that the animation positively impacted on their preparation with similar ratings before and after the scan, and the impact on preparation was rated greater by younger children. There were no group differences between healthy children and those with the neurological disorder for ratings of anxiety, impact on preparation and expectation of the experience. This evaluation demonstrates accessibility, acceptability and relevance of internet-based educational animation for typically developing children, and children with a neurodisability aged 6 to 11 years, with positive impact on preparation for MRI. Advances in knowledge: The internet-based educational animation provides a widely accessible tool to support preparation of children for non-sedated MRI.

SU-D-207A-04: Use of Gradient Echo Plural Contrast Imaging (GEPCI) in MR-Guided Radiation Therapy: A Feasibility Study Targeting Brain Treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, B; Rao, Y; Tsien, C

Purpose: To implement the Gradient Echo Plural Contrast Imaging(GEPCI) technique in MRI-simulation for radiation therapy and assess the feasibility of using GEPCI images with advanced inhomogeneity correction in MRI-guided radiotherapy for brain treatment. Methods: An optimized multigradient-echo GRE sequence (TR=50ms;TE1=4ms;delta-TE=4ms;flip angle=300,11 Echoes) was developed to generate both structural (T1w and T2*w) and functional MRIs (field and susceptibility maps) from a single acquisition. One healthy subject (Subject1) and one post-surgical brain cancer patient (Subject2) were scanned on a Philips Ingenia 1.5T MRI used for radiation therapy simulation. Another healthy subject (Subject3) was scanned on a 0.35T MRI-guided radiotherapy (MR-IGRT) system (ViewRay).more » A voxel spread function (VSF) was used to correct the B0 inhomogeneities caused by surgical cavities and edema for Subject2. GEPCI images and standard radiotherapy planning MRIs for this patient were compared focusing the delineation of radiotherapy target region. Results: GEPCI brain images were successfully derived from all three subjects with scan times of <7 minutes. The images derived for Subjects1&2 demonstrated that GEPCI can be applied and combined into radiotherapy MRI simulation. Despite low field, T1-weighted and R2* images were successfully reconstructed for Subject3 and were satisfactory for contour and target delineation. The R2* distribution of grey matter (center=12,FWHM=4.5) and white matter (center=14.6, FWHM=2) demonstrated the feasibility for tissue segmentation and quantification. The voxel spread function(VSF) corrected surgical site related inhomogeneities for Subject2. R2* and quantitative susceptibility map(QSM) images for Subject2 can be used to quantitatively assess the brain structure response to radiation over the treatment course. Conclusion: We implemented the GEPCI technique in MRI-simulation and in MR-IGRT system for radiation therapy. The images demonstrated that it is feasible to adopt this technique in radiotherapy for structural delineation. The preliminary data also enable the opportunity for quantitative assessment of radiation response of the target region and normal tissue.« less

Performing magnetic resonance imaging in patients with implantable pacemakers and defibrillators: results of a European Heart Rhythm Association survey.

PubMed

Marinskis, Germanas; Bongiorni, Maria Grazia; Dagres, Nikolaos; Dobreanu, Dan; Lewalter, Thorsten; Blomström-Lundqvist, Carina

2012-12-01

The purpose of our survey was to evaluate the experience, current practice and attitudes of performing magnetic resonance imaging (MRI) studies in patients with cardiac implantable electronic devices. Fifty-one centre-members of European Heart Rhythm Association Research network have responded to the survey. According to the obtained data, 55.2% of responding centres do not perform MRI scans in patients with non-MRI-certified pacemakers and 65.8% in patients with such implantable cardioverter defibrillators (ICDs). Reported complication rate in patients with non-MRI-certified devices is low and conforms to the literature data. Experience with newer MRI-compatible pacemakers and ICDs is limited to single cases in most centres. This survey shows limited experience with performing MRI studies in patients with implanted pacemakers and ICDs. In concordance with available guidelines, most centres limit MRI scans in patients with non-MRI-certified devices. The implant numbers for MRI-certified devices and experience with performing MRI scans in these patients are still low.

Cognitive disorders after sporadic ecstasy use? A case report.

PubMed

Ruis, Carla; Postma, Albert; Bouvy, Willem; van der Ham, Ineke

2015-01-01

Memory problems and changes in hippocampal structures after chronic ecstasy use are well described in the literature. Cognitive problems after incidental ecstasy use are rare, and the few patients described in case reports returned to their normal cognitive level after a relative short period. FV is a 39-year-old man who used an ecstasy tablet in 2005. This resulted in severe confusion for a few days. The confusion was followed by persistent memory complaints and difficulties orientating in new surroundings. An extensive neuropsychological examination 7 years after the ecstasy use revealed a severe memory disorder. Furthermore, his performance on a virtual reality test of navigation showed serious problems navigating in new surroundings. In comparison with matched control subjects (Bayesian approach for single case studies) his scores were significantly impaired on several subtasks of the navigation test. On a magnetic resonance imaging (MRI) scan of the brain bilateral hippocampal atrophy and sclerosis were visible, comparable to previous MRI studies describing hippocampal damage following ecstasy ingestion. This case report describes persistent memory and navigation disorders after sporadic ecstasy use, supported by structural brain abnormalities seen on the MRI scan. These findings revive the debate on whether sporadic ecstasy use can cause persistent cognitive deficits.

Provision of magnetic resonance imaging for patients with 'MR-conditional' cardiac implantable electronic devices: an unmet clinical need.

PubMed

Sabzevari, Kian; Oldman, James; Herrey, Anna S; Moon, James C; Kydd, Anna C; Manisty, Charlotte

2017-03-01

Increasing need for magnetic resonance imaging (MRI) has driven the development of MR-conditional cardiac implantable electronic devices (CIEDs; pacemakers and defibrillators); however, patients still report difficulties obtaining scans. We sought to establish current provision for MRI scanning of patients with CIEDs in England. A survey was distributed to all hospitals in England with MRI, to assess current practice. Information requested included whether hospitals currently offer MRI to this patient group, the number and type of scans acquired, local safety considerations, complications experienced and perceived obstacles to service provision in those departments not currently offering it. Responses were received from 195 of 227 (86%) of hospitals surveyed. Although 98% of departments were aware of MR-conditional devices, only 46% (n = 89) currently offer MRI scans to patients with CIED's; of these, 85% of departments perform ≤10 scans per year. No major complications were reported from MRI scanning in patients with MR-conditional devices. Current barriers to service expansion include perceived concerns regarding potential risk, lack of training, logistical difficulties, and lack of cardiology support. Provision of MRI for patients with CIEDs is currently poor, despite increasing numbers of patients with MR-conditional devices and extremely low reported complication rates. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

Final Technical Report for DOE Grant DE-FG02-08CH11515

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernstein, Dr. Ira Mark

2012-12-31

The year 2008 resulted in 99 scans that were funded through NIH agencies. An additional 43 MRI scans were funded by industry. Over 250 scans were acquired by various investigators as pilot data to be used for future grant applications. While these numbers are modest in comparison to most busy research MRI Centers, they are in line with that of a newly established MRI research facility. The initial 12-18 months of operation were primarily dedicated to establishing new IRB approved research studies, and acquiring pilot data for future grant applications. During the year 2009 the MRI Center continued to showmore » positive growth with respect to funded studies and the number of scan sessions. The number of NIH sponsored scans increased to 242 and the number of industry funded studies climbed to 81. This more than doubled our numbers of funded scans over the previous year. In addition, 398 scans were acquired as pilot data; most of which were fMRI's. The MRI Center continued to expand with additional researchers who were interested in probing the brain's response to chronic pain. Other studies looked at regions of brain activation in patients with impulsivity disorders; including smokers. A large majority of the imaging studies were focused on the brain; however, the MRI Center continued to accommodate the needs of various types of investigators, who studied various types of human pathology. Studies of porcine cardiac function and myocardial perfusion were performed. Another study of ultra-fast acute abdominal MRI in children was underway; eventually leading to publication in AJR. These non-neuro type research projects allowed the MRI Center to expand upon the depth and breadth of service that has now become available to researchers at UVM. The UVM MRI Center became the first clinical/research site in North America to install dual radio frequency (RF) amplifiers on a 3T MRI system. The use of dual RF amplifiers helps to eliminate standing wave artifacts that are prevalent at 3T. Standing wave artifacts often rendered spine or abdominal 3T MR images to be poor quality or unreadable prior to the availability of multi-transmit. A research collaboration agreement with Philips Healthcare, Best, Netherlands allowed our site to have first use of the technology; while at the same time giving us the opportunity to provide critical feedback to Philips Healthcare about our experiences with multi-transmit. This dramatically improved image quality for 3T MRI sites across the US and the world. Philips has stationed an onsite MRI physicist at UVM to work collaboratively with researchers at the University of Vermont on various MRI related projects. He has worked collaboratively with UVM investigators toward the design and publication of several journal articles and abstracts during his time at UVM. As the MRI Center advanced through the year 2010, an additional MRI technologist and a MRI physicist were hired to accommodate the increased demand for MRI scanning and data processing expertise. This enabled us to not only expand our hours of operation; it also helped to augment our MRI pulse programming and data processing capabilities. Studies that used state-of-the-art MRI techniques like pseudo continuous arterial spin labeling (pCASL) allowed researchers from the Department of Obstetrics and Reproductive Services to obtain non-contrast brain perfusion values of women to help them to better understand the effects of preeclampsia. At year-end 2010 the MRI Center completed 303 NIH funded and 198 industry funded scans. The number of no charge pilot scans decreased to 189.« less

[Microinjection Monitoring System Design Applied to MRI Scanning].

PubMed

Xu, Yongfeng

2017-09-30

A microinjection monitoring system applied to the MRI scanning was introduced. The micro camera probe was used to stretch into the main magnet for real-time video injection monitoring of injection tube terminal. The programming based on LabVIEW was created to analysis and process the real-time video information. The feedback signal was used for intelligent controlling of the modified injection pump. The real-time monitoring system can make the best use of injection under the condition that the injection device was away from the sample which inside the magnetic room and unvisible. 9.4 T MRI scanning experiment showed that the system in ultra-high field can work stability and doesn't affect the MRI scans.

[MRI and CT-scan in presumed benign ovarian tumors].

PubMed

Thomassin-Naggara, I; Bazot, M

2013-12-01

Radiological examinations are required for the assessment of complex or indeterminate ovarian masses, mainly using MRI and CT-scan. MRI provides better tissue characterization than Doppler ultrasound or CT-scan (LE2). Pelvic MRI is recommended in case of an indeterminate or complex ovarian ultrasonographic mass (grade B). The protocol of a pelvic MRI should include morphological T1 and T2 sequences (grade B). In case of solid portion, perfusion and diffusion sequences are recommended (grade C). In case of doubt about the diagnosis of ovarian origin, pelvic MRI is preferred over the CT-scan (grade C). MRI is the technique of choice for the difference between functional and organic ovarian lesion diagnosis (grade C). It can be useful in case of clinical diagnostic uncertainty between polycystic ovary syndrome and ovarian hyperstimulation and multilocular ovarian tumor syndrome (grade C). No MRI classification for ovarian masses is currently validated. The establishment of a presumption of risk of malignancy is required in a MRI report of adnexal mass with if possible a guidance on the histological diagnosis. In the absence of clinical or sonographic diagnosis, pelvic CT-scan is recommended in the context of acute painful pelvic mass in non-pregnant patients (grade C). It specifies the anomalies and allows the differential diagnosis with digestive and urinary diseases (LE4). Given the lack of data in the literature, the precautionary principle must be applied to the realization of a pelvic MRI in a pregnant patient. A risk-benefit balance should be evaluated case by case by the clinician and the radiologist and information should be given to the patient. In an emergency situation during pregnancy, pelvic MRI is an alternative to CT-scan for the exploration of acute pelvic pain in case of uncertain sonographic diagnosis (grade C). Copyright © 2013. Published by Elsevier Masson SAS.

The cerebellar development in chinese children-a study by voxel-based volume measurement of reconstructed 3D MRI scan.

PubMed

Wu, Kuan-Hsun; Chen, Chia-Yuan; Shen, Ein-Yiao

2011-01-01

Cerebellar disorder was frequently reported to have relation with structural brain volume alteration and/or morphology change. In dealing with such clinical situations, we need a convenient and noninvasive imaging tool to provide clinicians with a means of tracing developmental changes in the cerebellum. Herein, we present a new daily practice method for cerebellum imaging that uses a work station and a software program to process reconstructed 3D neuroimages after MRI scanning. In a 3-y period, 3D neuroimages reconstructed from MRI scans of 50 children aged 0.2-12.7 y were taken. The resulting images were then statistically analyzed against a growth curve. We observed a remarkable increase in the size of the cerebellum in the first 2 y of life. Furthermore, the unmyelinated cerebellum grew mainly between birth and 2 y of age in the postnatal stage. In contrast, the postnatal development of the brain mainly depended on the growth of myelinated cerebellum from birth through adolescence. This study presents basic data from a study of ethnic Chinese children's cerebellums using reconstructed 3D brain images. Based on the technique we introduce here, clinicians can evaluate the growth of the brain.

Diagnostic Value of MRI in Patients With Implanted Pacemakers and Implantable Cardioverter-Defibrillators Across a Cross Population: Does the Benefit Justify the Risk? A Proof of Concept Study.

PubMed

Samar, Huma; Yamrozik, June A; Williams, Ronald B; Doyle, Mark; Shah, Moneal; Bonnet, Christopher A; Biederman, Robert W W

2017-09-01

The objective of this study was to assess the diagnostic usefulness of thoracic and nonthoracic magnetic resonance imaging (MRI) imaging in patients with implantable cardiac devices (permanent pacemaker or implantable cardioverter-defibrillators [ICDs]) to determine if there was a substantial benefit to patients with regard to diagnosis and/or management. MRI is infrequently performed on patients with conventional pacemakers or ICDs. Multiple studies have documented the safety of MRI scans in patients with implanted devices, yet the diagnostic value of this approach has not been established. Evaluation data were acquired in 136 patients with implanted cardiac devices who underwent MRIs during a 10-year period at a single institution. Specific criteria were followed for all patients to objectively define if the diagnosis by MRI enhanced patient care; 4 questions were answered after scan interpretation by both MRI technologists and MRI physicians who performed the scan. 1) Did the primary diagnosis change? 2) Did the MRI provide additional information to the existing diagnosis? 3) Was the pre-MRI (tentative) diagnosis confirmed? 4) Did patient management change? If "Yes" was answered to any of the preceding questions, the MRI scan was considered to be of value to patient diagnosis and/or therapy. In 97% (n = 132) of patients, MR added value to patient diagnosis and management. In 49% (n = 67) of patients, MRI added additional valuable information to the primary diagnosis, and in 30% (n = 41) of patients, MRI changed the principle diagnosis and subsequent management of the patient. No safety issues were encountered, and no adverse effects of undergoing the MRI scan were noted in any patient. MRI in patients with implanted pacemakers and defibrillators added value to patient diagnosis and management, which justified the risk of the procedure. Published by Elsevier Inc.

SU-E-J-240: Development of a Novel 4D MRI Sequence for Real-Time Liver Tumor Tracking During Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhuang, L; Burmeister, J; Ye, Y

2015-06-15

Purpose: To develop a Novel 4D MRI Technique that is feasible for realtime liver tumor tracking during radiotherapy. Methods: A volunteer underwent an abdominal 2D fast EPI coronal scan on a 3.0T MRI scanner (Siemens Inc., Germany). An optimal set of parameters was determined based on image quality and scan time. A total of 23 slices were scanned to cover the whole liver in the test scan. For each scan position, the 2D images were retrospectively sorted into multiple phases based on breathing signal extracted from the images. Consequently the 2D slices with same phase numbers were stacked to formmore » one 3D image. Multiple phases of 3D images formed the 4D MRI sequence representing one breathing cycle. Results: The optimal set of scan parameters were: TR= 57ms, TE= 19ms, FOV read= 320mm and flip angle= 30°, which resulted in a total scan time of 14s for 200 frames (FMs) per slice and image resolution of (2.5mm,2.5mm,5.0mm) in three directions. Ten phases of 3D images were generated, each of which had 23 slices. Based on our test scan, only 100FMs were necessary for the phase sorting process which may lower the scan time to 7s/100FMs/slice. For example, only 5 slices/35s are necessary for a 4D MRI scan to cover liver tumor size ≤ 2cm leading to the possibility of tumor trajectory tracking every 35s during treatment. Conclusion: The novel 4D MRI technique we developed can reconstruct a 4D liver MRI sequence representing one breathing cycle (7s/ slice) without an external monitor. This technique can potentially be used for real-time liver tumor tracking during radiotherapy.« less

Characterization of tumor microvascular structure and permeability: comparison between magnetic resonance imaging and intravital confocal imaging

NASA Astrophysics Data System (ADS)

Reitan, Nina Kristine; Thuen, Marte; Goa, Pa˚L. Erik; de Lange Davies, Catharina

2010-05-01

Solid tumors are characterized by abnormal blood vessel organization, structure, and function. These abnormalities give rise to enhanced vascular permeability and may predict therapeutic responses. The permeability and architecture of the microvasculature in human osteosarcoma tumors growing in dorsal window chambers in athymic mice were measured by confocal laser scanning microscopy (CLSM) and dynamic contrast enhanced magnetic resonance imaging (DCE-MRI). Dextran (40 kDa) and Gadomer were used as molecular tracers for CLSM and DCE-MRI, respectively. A significant correlation was found between permeability indicators. The extravasation rate Ki as measured by CLSM correlated positively with DCE-MRI parameters, such as the volume transfer constant Ktrans and the initial slope of the contrast agent concentration-time curve. This demonstrates that these two techniques give complementary information. Extravasation was further related to microvascular structure and was found to correlate with the fractal dimension and vascular density. The structural parameter values that were obtained from CLSM images were higher for abnormal tumor vasculature than for normal vessels.

Mastocytosis: magnetic resonance imaging patterns of marrow disease.

PubMed

Avila, N A; Ling, A; Metcalfe, D D; Worobec, A S

1998-03-01

To report the bone marrow MRI findings of patients with mastocytosis and correlate them with clinical, pathologic, and radiographic features. Eighteen patients with mastocytosis had T1-weighted spin echo and short tau inversion recovery MRI of the pelvis at 0.5 T. In each patient the MR pattern of marrow disease was classified according to intensity and uniformity and was correlated with the clinical category of mastocytosis, bone marrow biopsy results, and radiographic findings. Two patients had normal MRI scans and normal bone marrow biopsies. One patient had a normal MRI scan and a marrow biopsy consistent with mastocytosis. Fifteen patients had abnormal MRI scans and abnormal marrow biopsies. There were several different MR patterns of marrow involvement; none was specifically associated with any given clinical category of mastocytosis. Fifteen of the 18 patients had radiographs of the pelvis; of those, 13 with abnormal MRI scans and abnormal marrow biopsies had the following radiographic findings: normal (nine); sclerosis (three); diffuse osteopenia (one). While radiographs are very insensitive for the detection of marrow abnormalities in mastocytosis, MRI is very sensitive and may display several different patterns of marrow involvement.

Prenatal magnetic resonance imaging: towards optimized patient information.

PubMed

Leithner, K; Pörnbacher, S; Assem-Hilger, E; Krampl-Bettelheim, E; Prayer, D

2009-08-01

To investigate the perception of fetal magnetic resonance imaging (MRI) by women confronted with the necessity of a targeted prenatal examination because of suspicion of an abnormality, in order to develop a pre-scan information leaflet tailored to the information requirements of these women. Sixty-two women were assessed by qualitative interview immediately before and after scanning. Data were analyzed by means of a qualitative content analysis. The transcribed interviews were coded within established categories, including knowledge of the purpose of the exam, understanding of the procedure, expectation of the baby's reaction, satisfaction with pre-information, experience of fetal MRI, distressing conditions during scanning, anxiety and suggestions for improvement of the scanning procedure. Pre-scan interviews indicated 66% of our sample to be well-informed about the purpose of fetal MRI. A realistic, detailed description of the examination was given by 37%. Only 32% expected the scanning to be safe for their baby. Despite the overall good tolerance of fetal MRI (63%), post-scan interviews revealed that 58% of women had experienced anxiety during MRI, which was partly due to the fearful perception of intensified fetal body movements during scanning. The quality of the pre-information leaflet was rated as sufficiently informative by 68% of the women. Suggestions for improvement were centered on physical conditions, the presence of the partner during scanning, and the availability of pre-scan briefings. Based on women's needs, detailed information about the fetal MRI procedure should be provided, containing clear-cut explanations about the purpose, course, method and possible distressing conditions. A leaflet describing these details should be given to women by the referring physician well in advance of the examination, and the woman given the opportunity to discuss unclear points.

Assessment of Safety and Interference Issues of Radio Frequency Identification Devices in 0.3 Tesla Magnetic Resonance Imaging and Computed Tomography

PubMed Central

Periyasamy, M.; Dhanasekaran, R.

2014-01-01

The objective of this study was to evaluate two issues regarding magnetic resonance imaging (MRI) including device functionality and image artifacts for the presence of radio frequency identification devices (RFID) in association with 0.3 Tesla at 12.7 MHz MRI and computed tomography (CT) scanning. Fifteen samples of RFID tags with two different sizes (wristband and ID card types) were tested. The tags were exposed to several MR-imaging conditions during MRI examination and X-rays of CT scan. Throughout the test, the tags were oriented in three different directions (axial, coronal, and sagittal) relative to MRI system in order to cover all possible situations with respect to the patient undergoing MRI and CT scanning, wearing a RFID tag on wrist. We observed that the tags did not sustain physical damage with their functionality remaining unaffected even after MRI and CT scanning, and there was no alternation in previously stored data as well. In addition, no evidence of either signal loss or artifact was seen in the acquired MR and CT images. Therefore, we can conclude that the use of this passive RFID tag is safe for a patient undergoing MRI at 0.3 T/12.7 MHz and CT Scanning. PMID:24701187

Combining anatomical, diffusion, and resting state functional magnetic resonance imaging for individual classification of mild and moderate Alzheimer's disease.

PubMed

Schouten, Tijn M; Koini, Marisa; de Vos, Frank; Seiler, Stephan; van der Grond, Jeroen; Lechner, Anita; Hafkemeijer, Anne; Möller, Christiane; Schmidt, Reinhold; de Rooij, Mark; Rombouts, Serge A R B

2016-01-01

Magnetic resonance imaging (MRI) is sensitive to structural and functional changes in the brain caused by Alzheimer's disease (AD), and can therefore be used to help in diagnosing the disease. Improving classification of AD patients based on MRI scans might help to identify AD earlier in the disease's progress, which may be key in developing treatments for AD. In this study we used an elastic net classifier based on several measures derived from the MRI scans of mild to moderate AD patients (N = 77) from the prospective registry on dementia study and controls (N = 173) from the Austrian Stroke Prevention Family Study. We based our classification on measures from anatomical MRI, diffusion weighted MRI and resting state functional MRI. Our unimodal classification performance ranged from an area under the curve (AUC) of 0.760 (full correlations between functional networks) to 0.909 (grey matter density). When combining measures from multiple modalities in a stepwise manner, the classification performance improved to an AUC of 0.952. This optimal combination consisted of grey matter density, white matter density, fractional anisotropy, mean diffusivity, and sparse partial correlations between functional networks. Classification performance for mild AD as well as moderate AD also improved when using this multimodal combination. We conclude that different MRI modalities provide complementary information for classifying AD. Moreover, combining multiple modalities can substantially improve classification performance over unimodal classification.

A Fully-Automated Subcortical and Ventricular Shape Generation Pipeline Preserving Smoothness and Anatomical Topology

PubMed Central

Tang, Xiaoying; Luo, Yuan; Chen, Zhibin; Huang, Nianwei; Johnson, Hans J.; Paulsen, Jane S.; Miller, Michael I.

2018-01-01

In this paper, we present a fully-automated subcortical and ventricular shape generation pipeline that acts on structural magnetic resonance images (MRIs) of the human brain. Principally, the proposed pipeline consists of three steps: (1) automated structure segmentation using the diffeomorphic multi-atlas likelihood-fusion algorithm; (2) study-specific shape template creation based on the Delaunay triangulation; (3) deformation-based shape filtering using the large deformation diffeomorphic metric mapping for surfaces. The proposed pipeline is shown to provide high accuracy, sufficient smoothness, and accurate anatomical topology. Two datasets focused upon Huntington's disease (HD) were used for evaluating the performance of the proposed pipeline. The first of these contains a total of 16 MRI scans, each with a gold standard available, on which the proposed pipeline's outputs were observed to be highly accurate and smooth when compared with the gold standard. Visual examinations and outlier analyses on the second dataset, which contains a total of 1,445 MRI scans, revealed 100% success rates for the putamen, the thalamus, the globus pallidus, the amygdala, and the lateral ventricle in both hemispheres and rates no smaller than 97% for the bilateral hippocampus and caudate. Another independent dataset, consisting of 15 atlas images and 20 testing images, was also used to quantitatively evaluate the proposed pipeline, with high accuracy having been obtained. In short, the proposed pipeline is herein demonstrated to be effective, both quantitatively and qualitatively, using a large collection of MRI scans. PMID:29867332

A Fully-Automated Subcortical and Ventricular Shape Generation Pipeline Preserving Smoothness and Anatomical Topology.

PubMed

Tang, Xiaoying; Luo, Yuan; Chen, Zhibin; Huang, Nianwei; Johnson, Hans J; Paulsen, Jane S; Miller, Michael I

2018-01-01

In this paper, we present a fully-automated subcortical and ventricular shape generation pipeline that acts on structural magnetic resonance images (MRIs) of the human brain. Principally, the proposed pipeline consists of three steps: (1) automated structure segmentation using the diffeomorphic multi-atlas likelihood-fusion algorithm; (2) study-specific shape template creation based on the Delaunay triangulation; (3) deformation-based shape filtering using the large deformation diffeomorphic metric mapping for surfaces. The proposed pipeline is shown to provide high accuracy, sufficient smoothness, and accurate anatomical topology. Two datasets focused upon Huntington's disease (HD) were used for evaluating the performance of the proposed pipeline. The first of these contains a total of 16 MRI scans, each with a gold standard available, on which the proposed pipeline's outputs were observed to be highly accurate and smooth when compared with the gold standard. Visual examinations and outlier analyses on the second dataset, which contains a total of 1,445 MRI scans, revealed 100% success rates for the putamen, the thalamus, the globus pallidus, the amygdala, and the lateral ventricle in both hemispheres and rates no smaller than 97% for the bilateral hippocampus and caudate. Another independent dataset, consisting of 15 atlas images and 20 testing images, was also used to quantitatively evaluate the proposed pipeline, with high accuracy having been obtained. In short, the proposed pipeline is herein demonstrated to be effective, both quantitatively and qualitatively, using a large collection of MRI scans.

Effect of live music therapy for patients undergoing magnetic resonance imaging.

PubMed

Walworth, Darcy D

2010-01-01

The purpose of the current study was to identify the effects of live music therapy interventions compared with preferred recorded music for patients undergoing MRI scans. To date, there has not been a published study involving the use of live music therapy during MRI scans. The current study investigated the differences between teenage through adult patients receiving live music therapy intervention during outpatient MRI scans versus the standard protocol of care listening to recorded music (N = 88). Subjects ranged in age from 15 to 93 years old. Results indicated subjects who received the live music therapy protocol reported significantly better perception of the MRI procedure (p < 0.05). Additionally, subjects receiving the live music therapy protocol had fewer scans repeated due to movement. Of the repeated images, 26% occurred in the live music group and 73% occurred in the recorded music group. Subjects receiving live music therapy also requested less breaks from the scan. Two percent of the live music subjects requested a break and 17.6% of the control patients requested breaks. When comparing the same type of scan between groups, subjects receiving the live music protocol required less time to complete the scans. For lumbar scans without contrast (N = 14, n = 7, n = 7), live music subjects spent an average of 4.63 less min per scan for a total of 32 less min for 7 subjects. For brain scans (N = 8, n = 4, n = 4), live music subjects spent an average of 5.8 less min per scan for a total of 23 less min for 4 subjects. Results of the current study supports the use of live music therapy intervention for teenage and adult patients undergoing MRI scans to reduce patient anxiety and improve patient perception of the scan experience. Additionally, live music therapy has the potential to shorten the length of time required for patients to complete MRI scans due to decreased patient movements and fewer breaks requested during the scans. The cost savings impact of reduced procedure time can positively impact the facility productivity by allowing more scans to be scheduled daily.

Assessment of Biomarkers Associated with Joint Injury and Subsequent Post-Traumatic Arthritis

DTIC Science & Technology

2015-10-01

osteoarthritis, articular fracture, joint injury, trauma, biomarker, inflammation, MRI , knee, mouse model, translational research. 3. OVERALL PROJECT...intervention. MRI imaging of the injured knee will be obtained to assess the articular cartilage. Degenerative changes in the cartilage and joint space...successfully enrolled patients, collected and stored biosamples, obtained all post-operative MRI scans and are continuing to obtain 18- month MRI scans for

Reproducibility and Temporal Structure in Weekly Resting-State fMRI over a Period of 3.5 Years

PubMed Central

Choe, Ann S.; Jones, Craig K.; Joel, Suresh E.; Muschelli, John; Belegu, Visar; Caffo, Brian S.; Lindquist, Martin A.; van Zijl, Peter C. M.; Pekar, James J.

2015-01-01

Resting-state functional MRI (rs-fMRI) permits study of the brain’s functional networks without requiring participants to perform tasks. Robust changes in such resting state networks (RSNs) have been observed in neurologic disorders, and rs-fMRI outcome measures are candidate biomarkers for monitoring clinical trials, including trials of extended therapeutic interventions for rehabilitation of patients with chronic conditions. In this study, we aim to present a unique longitudinal dataset reporting on a healthy adult subject scanned weekly over 3.5 years and identify rs-fMRI outcome measures appropriate for clinical trials. Accordingly, we assessed the reproducibility, and characterized the temporal structure of, rs-fMRI outcome measures derived using independent component analysis (ICA). Data was compared to a 21-person dataset acquired on the same scanner in order to confirm that the values of the single-subject RSN measures were within the expected range as assessed from the multi-participant dataset. Fourteen RSNs were identified, and the inter-session reproducibility of outcome measures—network spatial map, temporal signal fluctuation magnitude, and between-network connectivity (BNC)–was high, with executive RSNs showing the highest reproducibility. Analysis of the weekly outcome measures also showed that many rs-fMRI outcome measures had a significant linear trend, annual periodicity, and persistence. Such temporal structure was most prominent in spatial map similarity, and least prominent in BNC. High reproducibility supports the candidacy of rs-fMRI outcome measures as biomarkers, but the presence of significant temporal structure needs to be taken into account when such outcome measures are considered as biomarkers for rehabilitation-style therapeutic interventions in chronic conditions. PMID:26517540

Hearing loss associated with repeated MRI acquisition procedure-related acoustic noise exposure: an occupational cohort study.

PubMed

Bongers, Suzan; Slottje, Pauline; Kromhout, Hans

2017-11-01

To study the effects of repeated exposure to MRI-related acoustic noise during image acquisition procedures (scans) on hearing. A retrospective occupational cohort study was performed among workers of an MRI manufacturing facility (n=474). Longitudinal audiometry data from the facility's medical surveillance scheme collected from 1973 to 2010 were analysed by studying the association of cumulative exposure to MRI-related acoustic noise from voluntary (multiple) MRI scans and the hearing threshold of the volunteer. Repeated acoustic noise exposure during volunteer MRI scans was found to be associated with a small exposure-dependent increased rate change of hearing threshold level (dB/year), but the association was only found related to the number of voluntary MRI scans and not to modelled cumulative noise exposure (dB*hour) based on MRI-system type. The increased rate change of hearing threshold level was found to be statistically significant for the frequencies 500, 1000, 2000, 3000 and 4000 Hz in the right ear. From our longitudinal cohort study, it appeared that exposure to noise from voluntarily MRI scans may have resulted in a slight amount of hearing loss. Mandatory use of hearing protection might have prevented more severe hearing loss. Lack of consistency in findings between the left and right ears and between the two exposure measures prohibits definitive conclusions. Further research that addresses the study's methodological limitations is warranted to corroborate our findings. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

A new approach to define surface/sub-surface transition in gravel beds

NASA Astrophysics Data System (ADS)

Haynes, Heather; Ockelford, Anne-Marie; Vignaga, Elisa; Holmes, William

2012-12-01

The vertical structure of river beds varies temporally and spatially in response to hydraulic regime, sediment mobility, grain size distribution and faunal interaction. Implicit are changes to the active layer depth and bed porosity, both critical in describing processes such as armour layer development, surface-subsurface exchange processes and siltation/ sealing. Whilst measurements of the bed surface are increasingly informed by quantitative and spatial measurement techniques (e.g., laser displacement scanning), material opacity has precluded the full 3D bed structure analysis required to accurately define the surface-subsurface transition. To overcome this problem, this paper provides magnetic resonance imaging (MRI) data of vertical bed porosity profiles. Uniform and bimodal (σ g = 2.1) sand-gravel beds are considered following restructuring under sub-threshold flow durations of 60 and 960 minutes. MRI data are compared to traditional 2.5D laser displacement scans and six robust definitions of the surface-subsurface transition are provided; these form the focus of discussion.

Neural networks involved in learning lexical-semantic and syntactic information in a second language.

PubMed

Mueller, Jutta L; Rueschemeyer, Shirley-Ann; Ono, Kentaro; Sugiura, Motoaki; Sadato, Norihiro; Nakamura, Akinori

2014-01-01

The present study used functional magnetic resonance imaging (fMRI) to investigate the neural correlates of language acquisition in a realistic learning environment. Japanese native speakers were trained in a miniature version of German prior to fMRI scanning. During scanning they listened to (1) familiar sentences, (2) sentences including a novel sentence structure, and (3) sentences containing a novel word while visual context provided referential information. Learning-related decreases of brain activation over time were found in a mainly left-hemispheric network comprising classical frontal and temporal language areas as well as parietal and subcortical regions and were largely overlapping for novel words and the novel sentence structure in initial stages of learning. Differences occurred at later stages of learning during which content-specific activation patterns in prefrontal, parietal and temporal cortices emerged. The results are taken as evidence for a domain-general network supporting the initial stages of language learning which dynamically adapts as learners become proficient.

Hippocampal Structure and Human Cognition: Key Role of Spatial Processing and Evidence Supporting the Efficiency Hypothesis in Females

ERIC Educational Resources Information Center

Colom, Roberto; Stein, Jason L.; Rajagopalan, Priya; Martinez, Kenia; Hermel, David; Wang, Yalin; Alvarez-Linera, Juan; Burgaleta, Miguel; Quiroga, Ma. Angeles; Shih, Pei Chun; Thompson, Paul M.

2013-01-01

Here we apply a method for automated segmentation of the hippocampus in 3D high-resolution structural brain MRI scans. One hundred and four healthy young adults completed twenty one tasks measuring abstract, verbal, and spatial intelligence, along with working memory, executive control, attention, and processing speed. After permutation tests…

An exploration of GPs' use of MRI: a critical incident study.

PubMed

Robling, M; Kinnersley, P; Houston, H; Hourihan, M; Cohen, D; Hale, J

1998-06-01

Direct access to Magnetic Resonance Imaging (MRI) is becoming available to GPs in the UK, offering major benefits for the improved diagnosis and management of certain clinical conditions. Variations in usage of this service may be large, and effective locally produced guidelines are not currently available. The Department of General Practice is conducting a research programme to develop and evaluate methods to optimize MRI use by GPs. We aimed to describe the current use of MRI by GPs in South Glamorgan; to summarize their reasons for requesting MRI; and to produce criteria to assess the appropriateness of magnetic resonance (MR) scan requests. Using the critical incident technique, 25 GPs were interviewed about recent scans requested for patients with knee and lumbar spine complaints. A local panel of primary and secondary care doctors was convened to develop criteria for assessing MR scan requests. Sixty-two scan requests were discussed. Doctors' reasons for requesting MR scans were identified and classified. Reasons for requests included personal, contextual and biomedical variables. Fifteen patients (24%) were managed in primary care following MRI when otherwise they would have been referred. When referrals were made, GPs felt able to reinforce the request and occasionally to direct the patient somewhere more appropriate. The panel reviewed the interview data to produce objective criteria to assess scan requests. The criteria reflect the relative importance of non-biomedical variables in the decision to request MRI. The study identified those reasons which are important to GPs when requesting MR scans and the impact of this new technology upon patient management. Interview data have been used to inform locally developed consensus criteria, which will be made available as practice guidelines as the research programme progresses.

Automatic Substitute Computed Tomography Generation and Contouring for Magnetic Resonance Imaging (MRI)-Alone External Beam Radiation Therapy From Standard MRI Sequences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dowling, Jason A., E-mail: jason.dowling@csiro.au; University of Newcastle, Callaghan, New South Wales; Sun, Jidi

Purpose: To validate automatic substitute computed tomography CT (sCT) scans generated from standard T2-weighted (T2w) magnetic resonance (MR) pelvic scans for MR-Sim prostate treatment planning. Patients and Methods: A Siemens Skyra 3T MR imaging (MRI) scanner with laser bridge, flat couch, and pelvic coil mounts was used to scan 39 patients scheduled for external beam radiation therapy for localized prostate cancer. For sCT generation a whole-pelvis MRI scan (1.6 mm 3-dimensional isotropic T2w SPACE [Sampling Perfection with Application optimized Contrasts using different flip angle Evolution] sequence) was acquired. Three additional small field of view scans were acquired: T2w, T2*w, and T1wmore » flip angle 80° for gold fiducials. Patients received a routine planning CT scan. Manual contouring of the prostate, rectum, bladder, and bones was performed independently on the CT and MR scans. Three experienced observers contoured each organ on MRI, allowing interobserver quantification. To generate a training database, each patient CT scan was coregistered to their whole-pelvis T2w using symmetric rigid registration and structure-guided deformable registration. A new multi-atlas local weighted voting method was used to generate automatic contours and sCT results. Results: The mean error in Hounsfield units between the sCT and corresponding patient CT (within the body contour) was 0.6 ± 14.7 (mean ± 1 SD), with a mean absolute error of 40.5 ± 8.2 Hounsfield units. Automatic contouring results were very close to the expert interobserver level (Dice similarity coefficient): prostate 0.80 ± 0.08, bladder 0.86 ± 0.12, rectum 0.84 ± 0.06, bones 0.91 ± 0.03, and body 1.00 ± 0.003. The change in monitor units between the sCT-based plans relative to the gold standard CT plan for the same dose prescription was found to be 0.3% ± 0.8%. The 3-dimensional γ pass rate was 1.00 ± 0.00 (2 mm/2%). Conclusions: The MR-Sim setup and automatic sCT generation methods using standard MR sequences generates realistic contours and electron densities for prostate cancer radiation therapy dose planning and digitally reconstructed radiograph generation.« less

Magnetic Transfer Contrast Accurately Localizes Substantia Nigra Confirmed by Histology

PubMed Central

Bolding, Mark S.; Reid, Meredith A.; Avsar, Kathy B.; Roberts, Rosalinda C.; Gamlin, Paul D.; Gawne, Timothy J.; White, David M.; den Hollander, Jan A.; Lahti, Adrienne C.

2012-01-01

Background Magnetic Resonance Imaging (MRI) has multiple contrast mechanisms. Like various staining techniques in histology, each contrast type reveals different information about the structure of the brain. However, it is not always clear how structures visible in MRI correspond to structures previously identified by histology. The purpose of this study was to determine if magnetic transfer contrast (MTC) or T2 contrast MRI was better at delineating the substantia nigra. Methods MRI scans were acquired in-vivo from two non-human primates (NHPs). The NHPs were subsequently euthanized, perfused, and their brains sectioned for histological analyses. Each slice was photographed prior to sectioning. Each brain was sectioned into approximately 500, 40-micron sections, encompassing most of the cortex, midbrain, and dorsal parts of the hindbrain. Levels corresponding to anatomical MRI images were selected. From these, adjacent sections were stained using Kluver Barrera (myelin and cell bodies) or tyrosine hydroxylase (TH) (dopaminergic neurons) immunohistochemistry. The resulting images were coregistered to the block-face images using a moving least squares algorithm with similarity transformations. MR images were similarly coregistered to the block-face images, allowing the structures in the MRI to be identified with structures in the histological images. Results We found that hyperintense (light) areas in MTC images were coextensive with the SN as delineated histologically. The hypointense (dark) areas in T2-weighted images were not coextensive with the SN, but extended partially into the SN and partially into the cerebral peduncles. Conclusions MTC is a more accurate contrast mechanism than T2-weighting for localizing the SN in vivo. PMID:22981657

Does MRI scan acceleration affect power to track brain change?

PubMed

Ching, Christopher R K; Hua, Xue; Hibar, Derrek P; Ward, Chadwick P; Gunter, Jeffrey L; Bernstein, Matt A; Jack, Clifford R; Weiner, Michael W; Thompson, Paul M

2015-01-01

The Alzheimer's Disease Neuroimaging Initiative recently implemented accelerated T1-weighted structural imaging to reduce scan times. Faster scans may reduce study costs and patient attrition by accommodating people who cannot tolerate long scan sessions. However, little is known about how scan acceleration affects the power to detect longitudinal brain change. Using tensor-based morphometry, no significant difference was detected in numerical summaries of atrophy rates from accelerated and nonaccelerated scans in subgroups of patients with Alzheimer's disease, early or late mild cognitive impairment, or healthy controls over a 6- and 12-month scan interval. Whole-brain voxelwise mapping analyses revealed some apparent regional differences in 6-month atrophy rates when comparing all subjects irrespective of diagnosis (n = 345). No such whole-brain difference was detected for the 12-month scan interval (n = 156). Effect sizes for structural brain changes were not detectably different in accelerated versus nonaccelerated data. Scan acceleration may influence brain measures but has minimal effects on tensor-based morphometry-derived atrophy measures, at least over the 6- and 12-month intervals examined here. Copyright © 2015 Elsevier Inc. All rights reserved.

Open access to MRI for general practitioners: 12 years' experience at one institution -- a retrospective analysis.

PubMed

Gough-Palmer, A L; Burnett, C; Gedroyc, W M

2009-08-01

The aim of this study was to evaluate 12 years of general practitioner (GP) use of open access MRI services at a single London teaching hospital. A retrospective analysis of reports from all GP requests for MRI scans between 1994 and 2005 was performed. The date, scanned body part, and requester details from 1798 scans requested by 209 individual GPs over a continuous 12-year period were recorded. All scans were then graded into four categories based on the severity of reported findings from normal to gross abnormality. Over the study period, GP requests as a percentage of the total (MRI) department workload remained low at approximately 2.6%. Spine, knee and brain requests constituted 86% (n = 1546) of requested scans. 48% (n = 868) of scans were reported as normal or minor degenerative changes only. 26% (n = 466) of scans demonstrated serious pathology that was likely to warrant hospital consultant referral. There was a wide range of scans requested per requester, from 1 to 240 over the period, with an average of 8.5 scans per GP. In conclusion, any department wishing to set up open access to MRI services for GPs could cover the majority of requests by offering spine, knee and brain imaging. The percentage of normal report rates for GP requests is comparable with previous studies of outpatient referrals. A large variation in requesting patterns between GPs suggests the need for increased communication between GPs and imaging departments to optimise use of the service.

7T Magnetization Transfer and Chemical Exchange Saturation Transfer MRI of Cortical Gray Matter: Can We Detect Neurochemical and Macromolecular Abnormalities

DTIC Science & Technology

2015-10-01

with fMRI , and CEST acquisitions. Analysis hurdles were noted in the qMT, which we discuss here. Recruitment continues in the MS cohort (all healthy...Saturation Transfer (CEST) • Magnetization Transfer (MT) • Brain • Cortical Gray Matter (cGM) • Multiple Sclerosis (MS) • Functional MRI ( fMRI ) • Pool Size...MPRAGE Anatomical – 2:12 • fMRI Resting State – 8:34 • fMRI N-Back task – 8:30 • fMRI Trailmaking task – 4:14 The current scan time for all scans is

Functional brain MRI in patients complaining of electrohypersensitivity after long term exposure to electromagnetic fields.

PubMed

Heuser, Gunnar; Heuser, Sylvia A

2017-09-26

Ten adult patients with electromagnetic hypersensitivity underwent functional magnetic resonance imaging (fMRI) brain scans. All scans were abnormal with abnormalities which were consistent and similar. It is proposed that fMRI brain scans be used as a diagnostic aid for determining whether or not a patient has electromagnetic hypersensitivity. Over the years we have seen an increasing number of patients who had developed multi system complaints after long term repeated exposure to electromagnetic fields (EMFs). These complaints included headaches, intermittent cognitive and memory problems, intermittent disorientation, and also sensitivity to EMF exposure. Regular laboratory tests were within normal limits in these patients. The patients refused to be exposed to radioactivity. This of course ruled out positron emission tomography (PET) and single-photon emission computed tomography (SPECT) brain scanning. This is why we ordered fMRI brain scans on these patients. We hoped that we could document objective abnormalities in these patients who had often been labeled as psychiatric cases. Ten patients first underwent a regular magnetic resonance imaging (MRI) brain scan, using a 3 Tesla Siemens Verio MRI open system. A functional MRI study was then performed in the resting state using the following sequences: A three-dimensional, T1-weighted, gradient-echo (MPRAGE) Resting state network. The echo-planar imaging (EPI) sequences for this resting state blood oxygenation level dependent (BOLD) scan were then post processed on a 3D workstation and the independent component analysis was performed separating out the various networks. Arterial spin labeling. Tractography and fractional anisotropy. All ten patients had abnormal functional MRI brain scans. The abnormality was often described as hyper connectivity of the anterior component of the default mode in the medial orbitofrontal area. Other abnormalities were usually found. Regular MRI studies of the brain were mostly unremarkable in these patients. We propose that functional MRI studies should become a diagnostic aid when evaluating a patient who claims electrohypersensitivity (EHS) and has otherwise normal studies. Interestingly, the differential diagnosis for the abnormalities seen on the fMRI includes head injury. It turns out that many of our patients indeed had a history of head injury which was then followed sometime later by the development of EHS. Many of our patients also had a history of exposure to potentially neurotoxic chemicals, especially mold. Head injury and neurotoxic chemical exposure may make a patient more vulnerable to develop EHS.

Segmentation of knee MRI using structure enhanced local phase filtering

NASA Astrophysics Data System (ADS)

Lim, Mikhiel; Hacihaliloglu, Ilker

2016-03-01

The segmentation of bone surfaces from magnetic resonance imaging (MRI) data has applications in the quanti- tative measurement of knee osteoarthritis, surgery planning for patient specific total knee arthroplasty and its subsequent fabrication of artificial implants. However, due to the problems associated with MRI imaging such as low contrast between bone and surrounding tissues, noise, bias fields, and the partial volume effect, segmentation of bone surfaces continues to be a challenging operation. In this paper, a new framework is presented for the enhancement of knee MRI scans prior to segmentation in order to obtain high contrast bone images. During the first stage, a new contrast enhanced relative total variation (RTV) regularization method is used in order to remove textural noise from the bone structures and surrounding soft tissue interface. This salient bone edge information is further enhanced using a sparse gradient counting method based on L0 gradient minimization, which globally controls how many non-zero gradients are resulted in order to approximate prominent bone structures in a structure-sparsity-management manner. The last stage of the framework involves incorporation of local phase bone boundary information in order to provide an intensity invariant enhancement of contrast between the bone and surrounding soft tissue. The enhanced images are segmented using a fast random walker algorithm. Validation against expert segmentation was performed on 10 clinical knee MRI images, and achieved a mean dice similarity coefficient (DSC) of 0.975.

Improving magnetic resonance imaging (MRI) examinations: Development and evaluation of an intervention to reduce movement in scanners and facilitate scan completion.

PubMed

Powell, Rachael; Ahmad, Mahadir; Gilbert, Fiona J; Brian, David; Johnston, Marie

2015-09-01

The movement of patients in magnetic resonance imaging (MRI) scanners results in motion artefacts which impair image quality. Non-completion of scans leads to delay in diagnosis and increased costs. This study aimed to develop and evaluate an intervention to enable patients to stay still in MRI scanners (reducing motion artefacts) and to enhance scan completion. Successful scan outcome was deemed to be completing the scan with no motion artefacts. Previous research indicated self-efficacy to predict successful scan outcome, and interviews with patients identified a need for procedural and sensory information to facilitate successful scan behaviour. A DVD intervention was developed which targeted self-efficacy and included procedural and sensory information. It was successfully piloted with 10 patients and then evaluated in a randomized controlled trial compared with the standard hospital information leaflet (intervention group N = 41; control group N = 42). The clinic radiographer, who was blind to group allocation, rated MRI scans for motion artefact and recorded whether the participant completed the scan; participants completed MRI self-efficacy and anxiety measures. Only one participant reported not finding the DVD useful. Thirty-five participants in the intervention group and 23 in the control group completed scans and had no motion artefacts, χ(2) (1, 83) = 7.84, p < .001 (relative risk of an unsatisfactory outcome in the control group/intervention group = 3.09). The intervention effect was mediated by self-efficacy. The DVD intervention was efficacious and warrants further research to examine generalizability. © 2015 The British Psychological Society.

MRI and PET Compatible Bed for Direct Co-Registration in Small Animals

NASA Astrophysics Data System (ADS)

Bartoli, Antonietta; Esposito, Giovanna; D'Angeli, Luca; Chaabane, Linda; Terreno, Enzo

2013-06-01

To obtain an accurate co-registration with stand-alone PET and MRI scanners, we developed a compatible bed system for mice and rats that enables both images to be acquired without repositioning the animals. MRI acquisitions were performed on a preclinical 7T scanner (Pharmascan, Bruker), whereas PET scans were acquired on a YAP-(S)PET (ISE s.r.l.). The bed performance was tested both on a phantom (NEMA Image Quality phantom) and in vivo (healthy rats and mice brain). Fiducial markers filled up with a drop of 18 F were visible in both modalities. Co-registration process was performed using the point-based registration technique. The reproducibility and accuracy of the co-registration were assessed using the phantom. The reproducibility of the translation distances was 0.2 mm along the z axis. On the other hand, the accuracy depended on the physical size of the phantom structures under investigation but was always lower than 4%. Regions of Interest (ROIs) drawn on the fused images were used for quantification purposes. PET and MRI intensity profiles on small structures of the phantom showed that the underestimation in activity concentration reached 90% in regions that were smaller than the PET spatial resolution, while the MRI allowed a good visualization of the 1 mm 0 rod. PET/MRI images of healthy mice and rats highlighted the expected superior capability of MRI to define brain structures. The simplicity of our developed MRI/PET compatible bed and the quality of the fused images obtained offers a promising opportunity for a future preclinical translation, particularly for neuroimaging studies.

Arm MRI scan

MedlinePlus

... MRI and often available in the emergency room. Alternative Names MRI - arm; Wrist MRI; MRI - wrist; Elbow ... any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should ...

Training verb argument structure production in agrammatic aphasia: Behavioral and neural recovery patterns

PubMed Central

Thompson, Cynthia K.; Riley, Ellyn A.; den Ouden, Dirk-Bart; Meltzer-Asscher, Aya; Lukic, Sladjana

2013-01-01

Introduction Neuroimaging and lesion studies indicate a left hemisphere network for verb and verb argument structure processing, involving both frontal and temporoparietal brain regions. Although their verb comprehension is generally unimpaired, it is well known that individuals with agrammatic aphasia often present with verb production deficits, characterized by an argument structure complexity hierarchy, indicating faulty access to argument structure representations for production and integration into syntactic contexts. Recovery of verb processing in agrammatism, however, has received little attention and no studies have examined the neural mechanisms associated with improved verb and argument structure processing. In the present study we trained agrammatic individuals on verbs with complex argument structure in sentence contexts and examined generalization to verbs with less complex argument structure. The neural substrates of improved verb production were examined using functional magnetic resonance imaging (fMRI). Methods Eight individuals with chronic agrammatic aphasia participated in the study (four experimental and four control participants). Production of three-argument verbs in active sentences was trained using a sentence generation task emphasizing the verb’s argument structure and the thematic roles of sentential noun phrases. Before and after training, production of trained and untrained verbs was tested in naming and sentence production and fMRI scans were obtained, using an action naming task. Results Significant pre- to post-training improvement in trained and untrained (one- and two-argument) verbs was found for treated, but not control, participants, with between-group differences found for verb naming, production of verbs in sentences, and production of argument structure. fMRI activation derived from post-treatment compared to pre-treatment scans revealed upregulation in cortical regions implicated for verb and argument structure processing in healthy controls. Conclusions Training verb deficits emphasizing argument structure and thematic role mapping is effective for improving verb and sentence production and results in recruitment of neural networks engaged for verb and argument structure processing in healthy individuals. PMID:23514929

Knee MRI scan

MedlinePlus

... CT scan of the knee Knee x-ray Alternative Names MRI - knee; Magnetic resonance imaging - knee Patient ... any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should ...

Progressive neurostructural changes in adolescent and adult patients with bipolar disorder.

PubMed

Lisy, Megan E; Jarvis, Kelly B; DelBello, Melissa P; Mills, Neil P; Weber, Wade A; Fleck, David; Strakowski, Stephen M; Adler, Caleb M

2011-06-01

Several lines of evidence suggest that bipolar disorder is associated with progressive changes in gray matter volume (GMV), particularly in brain structures involved in emotional regulation and expression. The majority of these studies however, have been cross-sectional in nature. In this study we compared baseline and follow-up scans in groups of bipolar disorder and healthy subjects. We hypothesized bipolar disorder subjects would demonstrate significant GMV changes over time. A total of 58 bipolar disorder and 48 healthy subjects participated in structural magnetic resonance imaging (MRI). Subjects were rescanned 3-34 months after their baseline MRI. MRI images were segmented, normalized to standard stereotactic space, and compared voxel-by-voxel using statistical parametrical mapping software (SPM2). A model was developed to investigate differences in GMV at baseline, and associated with time and episodes, as well as in comparison to healthy subjects. We observed increases in GMV in bipolar disorder subjects across several brain regions at baseline and over time, including portions of the prefrontal cortex as well as limbic and subcortical structures. Time-related changes differed to some degree between adolescent and adult bipolar disorder subjects. The interval between scans positively correlated with GMV increases in bipolar disorder subjects in portions of the prefrontal cortex, and both illness duration and number of depressive episodes were associated with increased GMV in subcortical and limbic structures. Our findings support suggestions that widely observed progressive neurofunctional changes in bipolar disorder patients may be related to structural brain abnormalities in anterior limbic structures. Abnormalities largely involve regions previously noted to be integral to emotional expression and regulation, and appear to vary by age. © 2011 John Wiley and Sons A/S.

Three-dimensional MRI-linac intra-fraction guidance using multiple orthogonal cine-MRI planes

NASA Astrophysics Data System (ADS)

Bjerre, Troels; Crijns, Sjoerd; Rosenschöld, Per Munck af; Aznar, Marianne; Specht, Lena; Larsen, Rasmus; Keall, Paul

2013-07-01

The introduction of integrated MRI-radiation therapy systems will offer live intra-fraction imaging. We propose a feasible low-latency multi-plane MRI-linac guidance strategy. In this work we demonstrate how interleaved acquired, orthogonal cine-MRI planes can be used for low-latency tracking of the 3D trajectory of a soft-tissue target structure. The proposed strategy relies on acquiring a pre-treatment 3D breath-hold scan, extracting a 3D target template and performing template matching between this 3D template and pairs of orthogonal 2D cine-MRI planes intersecting the target motion path. For a 60 s free-breathing series of orthogonal cine-MRI planes, we demonstrate that the method was capable of accurately tracking the respiration related 3D motion of the left kidney. Quantitative evaluation of the method using a dataset designed for this purpose revealed a translational error of 1.15 mm for a translation of 39.9 mm. We have demonstrated how interleaved acquired, orthogonal cine-MRI planes can be used for online tracking of soft-tissue target volumes.

Three-dimensional MRI-linac intra-fraction guidance using multiple orthogonal cine-MRI planes.

PubMed

Bjerre, Troels; Crijns, Sjoerd; af Rosenschöld, Per Munck; Aznar, Marianne; Specht, Lena; Larsen, Rasmus; Keall, Paul

2013-07-21

The introduction of integrated MRI-radiation therapy systems will offer live intra-fraction imaging. We propose a feasible low-latency multi-plane MRI-linac guidance strategy. In this work we demonstrate how interleaved acquired, orthogonal cine-MRI planes can be used for low-latency tracking of the 3D trajectory of a soft-tissue target structure. The proposed strategy relies on acquiring a pre-treatment 3D breath-hold scan, extracting a 3D target template and performing template matching between this 3D template and pairs of orthogonal 2D cine-MRI planes intersecting the target motion path. For a 60 s free-breathing series of orthogonal cine-MRI planes, we demonstrate that the method was capable of accurately tracking the respiration related 3D motion of the left kidney. Quantitative evaluation of the method using a dataset designed for this purpose revealed a translational error of 1.15 mm for a translation of 39.9 mm. We have demonstrated how interleaved acquired, orthogonal cine-MRI planes can be used for online tracking of soft-tissue target volumes.

An assessment of the intra- and inter-reliability of the lumbar paraspinal muscle parameters using CT scan and magnetic resonance imaging.

PubMed

Hu, Zhi-Jun; He, Jian; Zhao, Feng-Dong; Fang, Xiang-Qian; Zhou, Li-Na; Fan, Shun-Wu

2011-06-01

A reliability study was conducted. To estimate the intra- and intermeasurement errors in the measurements of functional cross-sectional area (FCSA), density, and T2 signal intensity of paraspinal muscles using computed tomography (CT) scan and magnetic resonance imaging (MRI). CT scan and MRI had been used widely to measure the cross-sectional area and degeneration of the back muscles in spine and muscle research. But there is still no systemic study to analyze the reliability of these measurements. This study measured the FCSA and fatty infiltration (density on CT scan and T2 signal intensity on MRI) of the paraspinal muscles at L3-L4, L4-L5, and L5-S1 in 29 patients with chronic low back pain. Two experienced musculoskeletal radiologists and one superior spine surgeon traced the region of interest twice within 3 weeks for measurement of the intra- and interobserver reliability. The intraclass correlation coefficients (ICCs) of the intra-reliability ranged from fair to excellent for FCSA, and good to excellent for fatty infiltration. The ICCs of the inter-reliability ranged from fair to excellent for FCSA, and good to excellent for fatty infiltration. There were no significant differences between CT scan and MRI in reliability results, except in the relative standard error of fatty infiltration measurement. The ICCs of the FCSA measurement between CT scan and MRI ranged from poor to good. The reliabilities of the CT scan and MRI for measuring the FCSA and fatty infiltration of the atrophied lumbar paraspinal muscles were acceptable. It was reliable for using uniform one image method for a single paraspinal muscle evaluation study. And the authors preferred to advise the MRI other than CT scan for paraspinal muscles measurements of FCSA and fatty infiltration.

A Tool for Interactive Data Visualization: Application to Over 10,000 Brain Imaging and Phantom MRI Data Sets.

PubMed

Panta, Sandeep R; Wang, Runtang; Fries, Jill; Kalyanam, Ravi; Speer, Nicole; Banich, Marie; Kiehl, Kent; King, Margaret; Milham, Michael; Wager, Tor D; Turner, Jessica A; Plis, Sergey M; Calhoun, Vince D

2016-01-01

In this paper we propose a web-based approach for quick visualization of big data from brain magnetic resonance imaging (MRI) scans using a combination of an automated image capture and processing system, nonlinear embedding, and interactive data visualization tools. We draw upon thousands of MRI scans captured via the COllaborative Imaging and Neuroinformatics Suite (COINS). We then interface the output of several analysis pipelines based on structural and functional data to a t-distributed stochastic neighbor embedding (t-SNE) algorithm which reduces the number of dimensions for each scan in the input data set to two dimensions while preserving the local structure of data sets. Finally, we interactively display the output of this approach via a web-page, based on data driven documents (D3) JavaScript library. Two distinct approaches were used to visualize the data. In the first approach, we computed multiple quality control (QC) values from pre-processed data, which were used as inputs to the t-SNE algorithm. This approach helps in assessing the quality of each data set relative to others. In the second case, computed variables of interest (e.g., brain volume or voxel values from segmented gray matter images) were used as inputs to the t-SNE algorithm. This approach helps in identifying interesting patterns in the data sets. We demonstrate these approaches using multiple examples from over 10,000 data sets including (1) quality control measures calculated from phantom data over time, (2) quality control data from human functional MRI data across various studies, scanners, sites, (3) volumetric and density measures from human structural MRI data across various studies, scanners and sites. Results from (1) and (2) show the potential of our approach to combine t-SNE data reduction with interactive color coding of variables of interest to quickly identify visually unique clusters of data (i.e., data sets with poor QC, clustering of data by site) quickly. Results from (3) demonstrate interesting patterns of gray matter and volume, and evaluate how they map onto variables including scanners, age, and gender. In sum, the proposed approach allows researchers to rapidly identify and extract meaningful information from big data sets. Such tools are becoming increasingly important as datasets grow larger.

Computer-based radiological longitudinal evaluation of meningiomas following stereotactic radiosurgery.

PubMed

Shimol, Eli Ben; Joskowicz, Leo; Eliahou, Ruth; Shoshan, Yigal

2018-02-01

Stereotactic radiosurgery (SRS) is a common treatment for intracranial meningiomas. SRS is planned on a pre-therapy gadolinium-enhanced T1-weighted MRI scan (Gd-T1w MRI) in which the meningioma contours have been delineated. Post-SRS therapy serial Gd-T1w MRI scans are then acquired for longitudinal treatment evaluation. Accurate tumor volume change quantification is required for treatment efficacy evaluation and for treatment continuation. We present a new algorithm for the automatic segmentation and volumetric assessment of meningioma in post-therapy Gd-T1w MRI scans. The inputs are the pre- and post-therapy Gd-T1w MRI scans and the meningioma delineation in the pre-therapy scan. The output is the meningioma delineations and volumes in the post-therapy scan. The algorithm uses the pre-therapy scan and its meningioma delineation to initialize an extended Chan-Vese active contour method and as a strong patient-specific intensity and shape prior for the post-therapy scan meningioma segmentation. The algorithm is automatic, obviates the need for independent tumor localization and segmentation initialization, and incorporates the same tumor delineation criteria in both the pre- and post-therapy scans. Our experimental results on retrospective pre- and post-therapy scans with a total of 32 meningiomas with volume ranges 0.4-26.5 cm[Formula: see text] yield a Dice coefficient of [Formula: see text]% with respect to ground-truth delineations in post-therapy scans created by two clinicians. These results indicate a high correspondence to the ground-truth delineations. Our algorithm yields more reliable and accurate tumor volume change measurements than other stand-alone segmentation methods. It may be a useful tool for quantitative meningioma prognosis evaluation after SRS.

Optimized 14 + 1 receive coil array and position system for 3D high-resolution MRI of dental and maxillomandibular structures.

PubMed

Sedlacik, Jan; Kutzner, Daniel; Khokale, Arun; Schulze, Dirk; Fiehler, Jens; Celik, Turgay; Gareis, Daniel; Smeets, Ralf; Friedrich, Reinhard E; Heiland, Max; Assaf, Alexandre T

2016-01-01

The purpose of this study was to design, build and test a multielement receive coil array and position system, which is optimized for three-dimensional (3D) high-resolution dental and maxillomandibular MRI with high patient comfort. A 14 + 1 coil array and positioning system, allowing easy handling by the technologists, reproducible positioning of the patients and high patient comfort, was tested with three healthy volunteers using a 3.0-T MRI machine (Siemens Skyra; Siemens Medical Solutions, Erlangen, Germany). High-resolution 3D T1 weighted, water excitation T1 weighted and fat-saturated T2 weighted imaging sequences were scanned, and 3D image data were reformatted in different orientations and curvatures to aid diagnosis. The high number of receiving coils and the comfortable positioning of the coil array close to the patient's face provided a high signal-to-noise ratio and allowed high quality, high resolution, 3D image data to be acquired within reasonable scan times owing to the possibility of parallel image acquisition acceleration. Reformatting the isotropic 3D image data in different views is helpful for diagnosis, e.g. panoramic reconstruction. The visibility of soft tissues such as the mandibular canal, nutritive canals and periodontal ligaments was exquisite. The optimized MRI receive coil array and positioning system for dental and oral-maxillofacial imaging provides a valuable tool for detecting and diagnosing pathologies in dental and oral-maxillofacial structures while avoiding radiation dose. The high patient comfort, as achieved by our design, is very crucial, since image artefacts due to movement or failing to complete the examination jeopardize the diagnostic value of MRI examinations.

Quantification of intra-fraction motion in breast radiotherapy using supine magnetic resonance imaging

NASA Astrophysics Data System (ADS)

van Heijst, Tristan C. F.; Philippens, Mariëlle E. P.; Charaghvandi, Ramona K.; den Hartogh, Mariska D.; Lagendijk, Jan J. W.; Desirée van den Bongard, H. J. G.; van Asselen, Bram

2016-02-01

In early-stage breast-cancer patients, accelerated partial-breast irradiation techniques (APBI) and hypofractionation are increasingly implemented after breast-conserving surgery (BCS). For a safe and effective radiation therapy (RT), the influence of intra-fraction motion during dose delivery becomes more important as associated fraction durations increase and targets become smaller. Current image-guidance techniques are insufficient to characterize local target movement in high temporal and spatial resolution for extended durations. Magnetic resonance imaging (MRI) can provide high soft-tissue contrast, allow fast imaging, and acquire images during longer periods. The goal of this study was to quantify intra-fraction motion using MRI scans from 21 breast-cancer patients, before and after BCS, in supine RT position, on two time scales. High-temporal 2-dimensional (2D) MRI scans (cine-MRI), acquired every 0.3 s during 2 min, and three 3D MRI scans, acquired over 20 min, were performed. The tumor (bed) and whole breast were delineated on 3D scans and delineations were transferred to the cine-MRI series. Consecutive scans were rigidly registered and delineations were transformed accordingly. Motion in sub-second time-scale (derived from cine-MRI) was generally regular and limited to a median of 2 mm. Infrequently, large deviations were observed, induced by deep inspiration, but these were temporary. Movement on multi-minute scale (derived from 3D MRI) varied more, although medians were restricted to 2.2 mm or lower. Large whole-body displacements (up to 14 mm over 19 min) were sparsely observed. The impact of motion on standard RT techniques is likely small. However, in novel hypofractionated APBI techniques, whole-body shifts may affect adequate RT delivery, given the increasing fraction durations and smaller targets. Motion management may thus be required. For this, on-line MRI guidance could be provided by a hybrid MRI/RT modality, such as the University Medical Center Utrecht MRI linear accelerator.

Anatomo-clinical overlapping maps (AnaCOM): a new method to create anatomo-functional maps from neuropsychological tests and structural MRI scan of subjects with brain lesions

NASA Astrophysics Data System (ADS)

Kinkingnehun, Serge R. J.; du Boisgueheneuc, Foucaud; Golmard, Jean-Louis; Zhang, Sandy X.; Levy, Richard; Dubois, Bruno

2004-04-01

We have developed a new technique to analyze correlations between brain anatomy and its neurological functions. The technique is based on the anatomic MRI of patients with brain lesions who are administered neuropsychological tests. Brain lesions of the MRI scans are first manually segmented. The MRI volumes are then normalized to a reference map, using the segmented area as a mask. After normalization, the brain lesions of the MRI are segmented again in order to redefine the border of the lesions in the context of the normalized brain. Once the MRI is segmented, the patient's score on the neuropsychological test is assigned to each voxel in the lesioned area, while the rest of the voxels of the image are set to 0. Subsequently, the individual patient's MRI images are superimposed, and each voxel is reassigned the average score of the patients who have a lesion at that voxel. A threshold is applied to remove regions having less than three overlaps. This process leads to an anatomo-functional map that links brain areas to functional loss. Other maps can be created to aid in analyzing the functional maps, such as one that indicates the 95% confidence interval of the averaged scores for each area. This anatomo-clinical overlapping map (AnaCOM) method was used to obtain functional maps from patients with lesions in the superior frontal gyrus. By finding particular subregions more responsible for a particular deficit, this method can generate new hypotheses to be tested by conventional group methods.

Fabrication of custom-shaped grafts for cartilage regeneration.

PubMed

Koo, Seungbum; Hargreaves, Brian A; Gold, Garry E; Dragoo, Jason L

2010-10-01

to create a custom-shaped graft through 3D tissue shape reconstruction and rapid-prototype molding methods using MRI data, and to test the accuracy of the custom-shaped graft against the original anatomical defect. An iatrogenic defect on the distal femur was identified with a 1.5 Tesla MRI and its shape was reconstructed into a three-dimensional (3D) computer model by processing the 3D MRI data. First, the accuracy of the MRI-derived 3D model was tested against a laser-scan based 3D model of the defect. A custom-shaped polyurethane graft was fabricated from the laser-scan based 3D model by creating custom molds through computer aided design and rapid-prototyping methods. The polyurethane tissue was laser-scanned again to calculate the accuracy of this process compared to the original defect. The volumes of the defect models from MRI and laser-scan were 537 mm3 and 405 mm3, respectively, implying that the MRI model was 33% larger than the laser-scan model. The average (±SD) distance deviation of the exterior surface of the MRI model from the laser-scan model was 0.4 ± 0.4 mm. The custom-shaped tissue created from the molds was qualitatively very similar to the original shape of the defect. The volume of the custom-shaped cartilage tissue was 463 mm3 which was 15% larger than the laser-scan model. The average (±SD) distance deviation between the two models was 0.04 ± 0.19 mm. This investigation proves the concept that custom-shaped engineered grafts can be fabricated from standard sequence 3-D MRI data with the use of CAD and rapid-prototyping technology. The accuracy of this technology may help solve the interfacial problem between native cartilage and graft, if the grafts are custom made for the specific defect. The major source of error in fabricating a 3D custom-shaped cartilage graft appears to be the accuracy of a MRI data itself; however, the precision of the model is expected to increase by the utilization of advanced MR sequences with higher magnet strengths.

Overview of Imaging Tests

MedlinePlus

... Overview of Imaging Tests Angiography Computed Tomography (CT) Magnetic Resonance Imaging (MRI) Plain X-Rays Radionuclide Scanning ... and radionuclide scanning Sound waves, as in ultrasonography Magnetic fields, as in magnetic resonance imaging (MRI) Substances ...

Advanced approach for intraoperative MRI guidance and potential benefit for neurosurgical applications.

PubMed

Busse, Harald; Schmitgen, Arno; Trantakis, Christos; Schober, Ralf; Kahn, Thomas; Moche, Michael

2006-07-01

To present an advanced approach for intraoperative image guidance in an open 0.5 T MRI and to evaluate its effectiveness for neurosurgical interventions by comparison with a dynamic scan-guided localization technique. The built-in scan guidance mode relied on successive interactive MRI scans. The additional advanced mode provided real-time navigation based on reformatted high-quality, intraoperatively acquired MR reference data, allowed multimodal image fusion, and used the successive scans of the built-in mode for quick verification of the position only. Analysis involved tumor resections and biopsies in either scan guidance (N = 36) or advanced mode (N = 59) by the same three neurosurgeons. Technical, surgical, and workflow aspects were compared. The image quality and hand-eye coordination of the advanced approach were improved. While the average extent of resection, neurologic outcome after functional MRI (fMRI) integration, and diagnostic yield appeared to be slightly better under advanced guidance, particularly for the main surgeon, statistical analysis revealed no significant differences. Resection times were comparable, while biopsies took around 30 minutes longer. The presented approach is safe and provides more detailed images and higher navigation speed at the expense of actuality. The surgical outcome achieved with advanced guidance is (at least) as good as that obtained with dynamic scan guidance. (c) 2006 Wiley-Liss, Inc.

Visualization of nigrosome 1 and its loss in PD

PubMed Central

Schwarz, Stefan T.; Pitiot, Alain; Stephenson, Mary C.; Lowe, James; Bajaj, Nin; Bowtell, Richard W.; Auer, Dorothee P.; Gowland, Penny A.

2013-01-01

Objective: This study assessed whether high-resolution 7 T MRI allowed direct in vivo visualization of nigrosomes, substructures of the substantia nigra pars compacta (SNpc) undergoing the greatest and earliest dopaminergic cell loss in Parkinson disease (PD), and whether any disease-specific changes could be detected in patients with PD. Methods: Postmortem (PM) midbrains, 2 from healthy controls (HCs) and 1 from a patient with PD, were scanned with high-resolution T2*-weighted MRI scans, sectioned, and stained for iron and neuromelanin (Perl), TH, and calbindin. To confirm the identification of nigrosomes in vivo on 7 T T2*-weighted scans, we assessed colocalization with neuromelanin-sensitive T1-weighted scans. We then assessed the ability to depict PD pathology on in vivo T2*-weighted scans by comparing data from 10 patients with PD and 8 age- and sex-matched HCs. Results: A hyperintense, ovoid area within the dorsolateral border of the otherwise hypointense SNpc was identified in the HC brains on in vivo and PM T2*-weighted MRI. Location, size, shape, and staining characteristics conform to nigrosome 1. Blinded assessment by 2 neuroradiologists showed consistent bilateral absence of this nigrosome feature in all 10 patients with PD, and bilateral presence in 7/8 HC. Conclusions: In vivo and PM MRI with histologic correlation demonstrates that high-resolution 7 T MRI can directly visualize nigrosome 1. The absence of nigrosome 1 in the SNpc on MRI scans might prove useful in developing a neuroimaging diagnostic test for PD. PMID:23843466

Automatic Atlas Based Electron Density and Structure Contouring for MRI-based Prostate Radiation Therapy on the Cloud

NASA Astrophysics Data System (ADS)

Dowling, J. A.; Burdett, N.; Greer, P. B.; Sun, J.; Parker, J.; Pichler, P.; Stanwell, P.; Chandra, S.; Rivest-Hénault, D.; Ghose, S.; Salvado, O.; Fripp, J.

2014-03-01

Our group have been developing methods for MRI-alone prostate cancer radiation therapy treatment planning. To assist with clinical validation of the workflow we are investigating a cloud platform solution for research purposes. Benefits of cloud computing can include increased scalability, performance and extensibility while reducing total cost of ownership. In this paper we demonstrate the generation of DICOM-RT directories containing an automatic average atlas based electron density image and fast pelvic organ contouring from whole pelvis MR scans.

TH-A-BRF-04: Intra-Fraction Motion Characterization for Early Stage Rectal Cancer Using Cine-MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kleijnen, J; Asselen, B; Burbach, M

2014-06-15

Purpose: To investigate the intra-fraction motion in patients with early stage rectal cancer using cine-MRI. Methods: Sixteen patient diagnosed with early stage rectal cancer underwent 1.5 T MR imaging prior to each treatment fraction of their short course radiotherapy (n=76). During each scan session, three 2D sagittal cine-MRIs were performed: at the beginning (Start), after 9:30 minutes (Mid), and after 18 minutes (End). Each cine-MRI has a duration of one minute at 2Hz temporal resolution, resulting in a total of 3:48 hours of cine-MRI. Additionally, standard T2-weighted (T2w) imaging was performed. Clinical target volume (CTV) an tumor (GTV) were delineatedmore » on the T2w scan and transferred to the first time-point of each cine-MRI scan. Within each cine-MRI, the first frame was registered to the remaining frames of the scan, using a non-rigid B-spline registration. To investigate potential drifts, a similar registration was performed between the first frame of the Start and End scans.To evaluate the motion, the distances by which the edge pixels of the delineations move in anterior-posterior (AP) and cranial-caudal (CC) direction, were determined using the deformation field of the registrations. The distance which incorporated 95% of these edge pixels (dist95%) was determined within each cine-MRI, and between Start- End scans, respectively. Results: Within a cine-MRI, we observed an average dist95% for the CTV of 1.3mm/1.5mm (SD=0.7mm/0.6mm) and for the GTV of 1.2mm/1.5mm (SD=0.8mm/0.9mm), in respectively AP/CC. For the CTV motion between the Start and End scan, an average dist95% of 5.5mm/5.3mm (SD=3.1mm/2.5mm) was found, in respectively AP/CC. For the GTV motion, an average dist95% of 3.6mm/3.9mm (SD=2.2mm/2.5mm) was found in AP/CC, respectively. Conclusion: Although intra-fraction motion within a one minute cine-MRI is limited, substantial intra-fraction motion was observed within the 18 minute time period between the Start and End cine-MRI.« less

MRI brain imaging.

PubMed

Skinner, Sarah

2013-11-01

General practitioners (GPs) are expected to be allowed to request MRI scans for adults for selected clinically appropriate indications from November 2013 as part of the expansion of Medicare-funded MRI services announced by the Federal Government in 2011. This article aims to give a brief overview of MRI brain imaging relevant to GPs, which will facilitate explanation of scan findings and management planning with their patients. Basic imaging techniques, common findings and terminology are presented using some illustrative case examples.

High prevalence of brain pathology in violent prisoners: a qualitative CT and MRI scan study.

PubMed

Schiltz, Kolja; Witzel, Joachim G; Bausch-Hölterhoff, Josef; Bogerts, Bernhard

2013-10-01

The aim of this study was to determine the frequency and extent of brain anomalies in a large sample of incarcerated violent offenders not previously considered neuropsychiatrically ill, in comparison with non-violent offenders and non-offending controls. MRI and CT brain scans from 287 male prison inmates (162 violent and 125 non-violent) not diagnosed as mentally ill before that were obtained due to headache, vertigo or psychological complaints during imprisonment were assessed and compared to 52 non-criminal controls. Brain scans were rated qualitatively with respect to evidence of structural brain damage. Each case received a semiquantitative rating of "normal" (=0), "questionably abnormal" (=1) or "definitely abnormal" (=2) for the lateral ventricles, frontal/parietal cortex and medial temporal structures bilaterally as well as third ventricle. Overall, offenders displayed a significantly higher rate of morphological abnormality, with the violent offenders scoring significantly higher than non-violent offenders and controls. This difference was statistically detectable for frontal/parietal cortex, medial temporal structures, third ventricle and the left but not the right lateral ventricle. The remarkable prevalence of brain pathology in convicted violent prisoners detectable by neuroradiological routine assessment not only highlights the importance of frontal and temporal structures in the control of social, and specifically of violent behaviour, but also raises questions on the legal culpability of violent offenders with brain abnormalities. The high proportion of undetected presence of structural brain damage emphasizes the need that in violent criminals, the comprehensive routine neuropsychiatric assessment usually performed in routine forensic psychiatric expertises should be complemented with brain imaging.

The accuracy of ultrashort echo time MRI sequences for medical additive manufacturing.

PubMed

van Eijnatten, Maureen; Rijkhorst, Erik-Jan; Hofman, Mark; Forouzanfar, Tymour; Wolff, Jan

2016-01-01

Additively manufactured bone models, implants and drill guides are becoming increasingly popular amongst maxillofacial surgeons and dentists. To date, such constructs are commonly manufactured using CT technology that induces ionizing radiation. Recently, ultrashort echo time (UTE) MRI sequences have been developed that allow radiation-free imaging of facial bones. The aim of the present study was to assess the feasibility of UTE MRI sequences for medical additive manufacturing (AM). Three morphologically different dry human mandibles were scanned using a CT and MRI scanner. Additionally, optical scans of all three mandibles were made to acquire a "gold standard". All CT and MRI scans were converted into Standard Tessellation Language (STL) models and geometrically compared with the gold standard. To quantify the accuracy of the AM process, the CT, MRI and gold-standard STL models of one of the mandibles were additively manufactured, optically scanned and compared with the original gold-standard STL model. Geometric differences between all three CT-derived STL models and the gold standard were <1.0 mm. All three MRI-derived STL models generally presented deviations <1.5 mm in the symphyseal and mandibular area. The AM process introduced minor deviations of <0.5 mm. This study demonstrates that MRI using UTE sequences is a feasible alternative to CT in generating STL models of the mandible and would therefore be suitable for surgical planning and AM. Further in vivo studies are necessary to assess the usability of UTE MRI sequences in clinical settings.

Journal Club: Shoulder MRI utilization: relationship of physician MRI equipment ownership to negative study frequency.

PubMed

Amrhein, Timothy J; Lungren, Matthew P; Paxton, Ben E; Srinivasan, Ramesh; Jung, Sin-Ho; Yu, Miao; Eastwood, James D; Kilani, Ramsey K

2013-09-01

The purpose of this article is to determine whether ownership of MRI equipment by ordering physicians influences the frequency of negative shoulder MRI scans. A retrospective review was performed of 1140 consecutive shoulder MRI scans ordered by two separate referring physician groups serving the same geographic community. The first group (financially incentivized) owned the scanners used and received technical fees for their use. The second group (non-financially incentivized) did not own the scanners used and had no direct financial interest. All examinations were performed with identical protocols and were interpreted by a single radiologist group without financial interest in the imaging equipment used. The frequency of negative examinations and the number of abnormalities in each positive study was tabulated for each group. A total of 1140 shoulder MRI scans met inclusion criteria; 255 were negative (142 for the financially incentivized group and 113 for the non-financially incentivized group). There were 25.6% more negative scans in the financially incentivized group (p=0.047). There was no statistically significant difference in the average number of lesions per positive scan (1.67 for the financially incentivized group and 1.71 for the non-financially incentivized group; p=0.34). No statistically significant difference was found in the frequency of 19 of 20 examined lesions. Shoulder MRI examinations referred by physicians with a financial interest in the imaging equipment used were significantly more likely to be negative. Positive examinations exhibited no statistically significant difference in the number of lesions per scan or in the frequency of 19 of 20 lesion subtypes. This finding suggests a highly similar distribution and severity of disease among the two patient groups.

Comparison of human septal nuclei MRI measurements using automated segmentation and a new manual protocol based on histology

PubMed Central

Butler, Tracy; Zaborszky, Laszlo; Pirraglia, Elizabeth; Li, Jinyu; Wang, Xiuyuan Hugh; Li, Yi; Tsui, Wai; Talos, Delia; Devinsky, Orrin; Kuchna, Izabela; Nowicki, Krzysztof; French, Jacqueline; Kuzniecky, Rubin; Wegiel, Jerzy; Glodzik, Lidia; Rusinek, Henry; DeLeon, Mony J.; Thesen, Thomas

2014-01-01

Septal nuclei, located in basal forebrain, are strongly connected with hippocampi and important in learning and memory, but have received limited research attention in human MRI studies. While probabilistic maps for estimating septal volume on MRI are now available, they have not been independently validated against manual tracing of MRI, typically considered the gold standard for delineating brain structures. We developed a protocol for manual tracing of the human septal region on MRI based on examination of neuroanatomical specimens. We applied this tracing protocol to T1 MRI scans (n=86) from subjects with temporal epilepsy and healthy controls to measure septal volume. To assess the inter-rater reliability of the protocol, a second tracer used the same protocol on 20 scans that were randomly selected from the 72 healthy controls. In addition to measuring septal volume, maximum septal thickness between the ventricles was measured and recorded. The same scans (n=86) were also analysed using septal probabilistic maps and Dartel toolbox in SPM. Results show that our manual tracing algorithm is reliable, and that septal volume measurements obtained via manual and automated methods correlate significantly with each other (p<001). Both manual and automated methods detected significantly enlarged septal nuclei in patients with temporal lobe epilepsy in accord with a proposed compensatory neuroplastic process related to the strong connections between septal nuclei and hippocampi. Septal thickness, which was simple to measure with excellent inter-rater reliability, correlated well with both manual and automated septal volume, suggesting it could serve as an easy-to-measure surrogate for septal volume in future studies. Our results call attention to the important though understudied human septal region, confirm its enlargement in temporal lobe epilepsy, and provide a reliable new manual delineation protocol that will facilitate continued study of this critical region. PMID:24736183

Comparison of human septal nuclei MRI measurements using automated segmentation and a new manual protocol based on histology.

PubMed

Butler, Tracy; Zaborszky, Laszlo; Pirraglia, Elizabeth; Li, Jinyu; Wang, Xiuyuan Hugh; Li, Yi; Tsui, Wai; Talos, Delia; Devinsky, Orrin; Kuchna, Izabela; Nowicki, Krzysztof; French, Jacqueline; Kuzniecky, Rubin; Wegiel, Jerzy; Glodzik, Lidia; Rusinek, Henry; deLeon, Mony J; Thesen, Thomas

2014-08-15

Septal nuclei, located in basal forebrain, are strongly connected with hippocampi and important in learning and memory, but have received limited research attention in human MRI studies. While probabilistic maps for estimating septal volume on MRI are now available, they have not been independently validated against manual tracing of MRI, typically considered the gold standard for delineating brain structures. We developed a protocol for manual tracing of the human septal region on MRI based on examination of neuroanatomical specimens. We applied this tracing protocol to T1 MRI scans (n=86) from subjects with temporal epilepsy and healthy controls to measure septal volume. To assess the inter-rater reliability of the protocol, a second tracer used the same protocol on 20 scans that were randomly selected from the 72 healthy controls. In addition to measuring septal volume, maximum septal thickness between the ventricles was measured and recorded. The same scans (n=86) were also analyzed using septal probabilistic maps and DARTEL toolbox in SPM. Results show that our manual tracing algorithm is reliable, and that septal volume measurements obtained via manual and automated methods correlate significantly with each other (p<.001). Both manual and automated methods detected significantly enlarged septal nuclei in patients with temporal lobe epilepsy in accord with a proposed compensatory neuroplastic process related to the strong connections between septal nuclei and hippocampi. Septal thickness, which was simple to measure with excellent inter-rater reliability, correlated well with both manual and automated septal volume, suggesting it could serve as an easy-to-measure surrogate for septal volume in future studies. Our results call attention to the important though understudied human septal region, confirm its enlargement in temporal lobe epilepsy, and provide a reliable new manual delineation protocol that will facilitate continued study of this critical region. Copyright © 2014 Elsevier Inc. All rights reserved.

Epileptic Networks in Focal Cortical Dysplasia Revealed Using Electroencephalography–Functional Magnetic Resonance Imaging

PubMed Central

Thornton, Rachel; Vulliemoz, Serge; Rodionov, Roman; Carmichael, David W; Chaudhary, Umair J; Diehl, Beate; Laufs, Helmut; Vollmar, Christian; McEvoy, Andrew W; Walker, Matthew C; Bartolomei, Fabrice; Guye, Maxime; Chauvel, Patrick; Duncan, John S; Lemieux, Louis

2011-01-01

Objective Surgical treatment of focal epilepsy in patients with focal cortical dysplasia (FCD) is most successful if all epileptogenic tissue is resected. This may not be evident on structural magnetic resonance imaging (MRI), so intracranial electroencephalography (icEEG) is needed to delineate the seizure onset zone (SOZ). EEG-functional MRI (fMRI) can reveal interictal discharge (IED)-related hemodynamic changes in the irritative zone (IZ). We assessed the value of EEG-fMRI in patients with FCD-associated focal epilepsy by examining the relationship between IED-related hemodynamic changes, icEEG findings, and postoperative outcome. Methods Twenty-three patients with FCD-associated focal epilepsy undergoing presurgical evaluation including icEEG underwent simultaneous EEG-fMRI at 3T. IED-related hemodynamic changes were modeled, and results were overlaid on coregistered T1-weighted MRI scans fused with computed tomography scans showing the intracranial electrodes. IED-related hemodynamic changes were compared with the SOZ on icEEG and postoperative outcome at 1 year. Results Twelve of 23 patients had IEDs during recording, and 11 of 12 had significant IED-related hemodynamic changes. The fMRI results were concordant with the SOZ in 5 of 11 patients, all of whom had a solitary SOZ on icEEG. Four of 5 had >50% reduction in seizure frequency following resective surgery. The remaining 6 of 11 patients had widespread or discordant regions of IED-related fMRI signal change. Five of 6 had either a poor surgical outcome (<50% reduction in seizure frequency) or widespread SOZ precluding surgery. Interpretation Comparison of EEG-fMRI with icEEG suggests that EEG-fMRI may provide useful additional information about the SOZ in FCD. Widely distributed discordant regions of IED-related hemodynamic change appear to be associated with a widespread SOZ and poor postsurgical outcome. ANN NEUROL 2011 PMID:22162063

MRI simulation: end-to-end testing for prostate radiation therapy using geometric pelvic MRI phantoms

NASA Astrophysics Data System (ADS)

Sun, Jidi; Dowling, Jason; Pichler, Peter; Menk, Fred; Rivest-Henault, David; Lambert, Jonathan; Parker, Joel; Arm, Jameen; Best, Leah; Martin, Jarad; Denham, James W.; Greer, Peter B.

2015-04-01

To clinically implement MRI simulation or MRI-alone treatment planning requires comprehensive end-to-end testing to ensure an accurate process. The purpose of this study was to design and build a geometric phantom simulating a human male pelvis that is suitable for both CT and MRI scanning and use it to test geometric and dosimetric aspects of MRI simulation including treatment planning and digitally reconstructed radiograph (DRR) generation. A liquid filled pelvic shaped phantom with simulated pelvic organs was scanned in a 3T MRI simulator with dedicated radiotherapy couch-top, laser bridge and pelvic coil mounts. A second phantom with the same external shape but with an internal distortion grid was used to quantify the distortion of the MR image. Both phantoms were also CT scanned as the gold-standard for both geometry and dosimetry. Deformable image registration was used to quantify the MR distortion. Dose comparison was made using a seven-field IMRT plan developed on the CT scan with the fluences copied to the MR image and recalculated using bulk electron densities. Without correction the maximum distortion of the MR compared with the CT scan was 7.5 mm across the pelvis, while this was reduced to 2.6 and 1.7 mm by the vendor’s 2D and 3D correction algorithms, respectively. Within the locations of the internal organs of interest, the distortion was <1.5 and <1 mm with 2D and 3D correction algorithms, respectively. The dose at the prostate isocentre calculated on CT and MRI images differed by 0.01% (1.1 cGy). Positioning shifts were within 1 mm when setup was performed using MRI generated DRRs compared to setup using CT DRRs. The MRI pelvic phantom allows end-to-end testing of the MRI simulation workflow with comparison to the gold-standard CT based process. MRI simulation was found to be geometrically accurate with organ dimensions, dose distributions and DRR based setup within acceptable limits compared to CT.

Anatomy of the psoas muscle and lumbar plexus with respect to the surgical approach for lateral transpsoas interbody fusion.

PubMed

Kepler, Christopher K; Bogner, Eric A; Herzog, Richard J; Huang, Russel C

2011-04-01

Lateral transpsoas interbody fusion (LTIF) is a minimally invasive technique that permits interbody fusion utilizing cages placed via a direct lateral retroperitoneal approach. We sought to describe the locations of relevant neurovascular structures based on MRI with respect to this novel surgical approach. We retrospectively reviewed consecutive lumbosacral spine MRI scans in 43 skeletally mature adults. MRI scans were independently reviewed by two readers to identify the location of the psoas muscle, lumbar plexus, femoral nerve, inferior vena cava and right iliac vein. Structures potentially at risk for injury were identified by: a distance from the anterior aspect of the adjacent vertebral bodies of <20 mm, representing the minimum retraction necessary for cage placement, and extension of vascular structures posterior to the anterior vertebral body, requiring anterior retraction. The percentage of patients with neurovascular structures at risk for left-sided approaches was 2.3% at L1-2, 7.0% at L2-3, 4.7% at L3-4 and 20.9% at L4-5. For right-sided approaches, this rose to 7.0% at L1-2, 7.0% at L2-3, 9.3% at L3-4 and 44.2% at L4-5, largely because of the relatively posterior right-sided vasculature. A relationship between the position of psoas muscle and lumbar plexus is described which allows use of the psoas position as a proxy for lumbar plexus position to identify patients who may be at risk, particularly at the L4-5 level. Further study will establish the clinical relevance of these measurements and the ability of neurovascular structures to be retracted without significant injury.

Rapid-sequence MRI for long-term surveillance for paraganglioma and phaeochromocytoma in patients with succinate dehydrogenase mutations.

PubMed

Daniel, Eleni; Jones, Robert; Bull, Matthew; Newell-Price, John

2016-12-01

Patients with SDHx mutations need long-term radiological surveillance for the development of paragangliomas and phaeochromocytomas, but no longitudinal data exist. The aim of the study was to assess the performance of rapid-sequence non-contrast magnetic resonance imaging (MRI) in the long-term monitoring of patients with SDHx mutations. Retrospective study between 2005 and 2015 at a University Hospital and regional endocrine genetics referral centre. Clinical and imaging data of 47 patients with SDHx mutations (SDHB (36), SDHC (6) and SDHD (5)) who had surveillance for detection of paragangliomas by rapid-sequence non-contrast MRI (base of skull to pubic symphysis) were collected. Twelve index cases (nine SDHB, one SDHC and two SDHD) and 35 mutation-positive relatives were monitored for a mean of 6.4 years (range 3.1-10.0 years). Mean age at the end of the study: SDHB 46.9 ± 17.6 years; SDHC 42.3 ± 24.4 years; SDHD 54.9 ± 10.6 years. On excluding imaging at initial diagnosis of index cases, 42 patients underwent 116 rapid-sequence MRI scans: 83 scans were negative and 31 scans were positive for sPGL/HNPGL in 13 patients. Most patients had multiple scans (n = number of patients (number of rapid-sequence MRI scans during screening)): n = 9 (2), n = 20 (3), n = 6 (4), n = 1 (6). Nine patients (three index) were diagnosed with new paragangliomas during surveillance and non-operated tumour size was monitored in nine patients. There were two false-positive scans (1.6%). Scans were repeated every 27 ± 9 months. Biannual rapid-sequence non-contrast MRI is effective to monitor patients with SDHx mutations for detection of new tumours and monitoring of known tumours. © 2016 European Society of Endocrinology.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, B; Yin, F; Cai, J

Purpose: To determine the variation in tumor contrast between different MRI sequences and between patients for the purpose of MRI-based treatment planning. Methods: Multiple MRI scans of 11 patients with cancer(s) in the liver were included in this IRB-approved study. Imaging sequences consisted of T1W MRI, Contrast-Enhanced T1W MRI, T2W MRI, and T2*/T1W MRI. MRI images were acquired on a 1.5T GE Signa scanner with a four-channel torso coil. We calculated the tumor-to-tissue contrast to noise ratio (CNR) for each MR sequence by contouring the tumor and a region of interest (ROI) in a homogeneous region of the liver usingmore » the Eclipse treatment planning software. CNR was calculated (I-Tum-I-ROI)/SD-ROI, where I-Tum and I-ROI are the mean values of the tumor and the ROI respectively, and SD-ROI is the standard deviation of the ROI. The same tumor and ROI structures were used in all measurements for different MR sequences. Inter-patient Coefficient of variation (CV), and inter-sequence CV was determined. In addition, mean and standard deviation of CNR were calculated and compared between different MR sequences. Results: Our preliminary results showed large inter-patient CV (range: 37.7% to 88%) and inter-sequence CV (range 5.3% to 104.9%) of liver tumor CNR, indicating great variations in tumor CNR between MR sequences and between patients. Tumor CNR was found to be largest in CE-T1W (8.5±7.5), followed by T2W (4.2±2.4), T1W (3.4±2.2), and T2*/T1W (1.7±0.6) MR scans. The inter-patient CV of tumor CNR was also the largest in CE-T1W (88%), followed by T1W (64.3%), T1W (56.2%), and T2*/T1W (37.7) MR scans. Conclusion: Large inter-sequence and inter-patient variations were observed in liver tumor CNR. CE-T1W MR images on average provided the best tumor CNR. Efforts are needed to optimize tumor contrast and its consistency for MRI-based treatment planning of cancer in the liver. This project is supported by NIH grant: 1R21CA165384.« less

Pelvis MRI scan

MedlinePlus

... and most often available in the emergency room. Alternative Names MRI - pelvis; MRI - hips; Pelvic MRI with ... any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should ...

The Use of Magnetic Resonance Imaging in Axial Spondyloarthritis: Time to Bridge the Gap Between Radiologists and Rheumatologists.

PubMed

Bennett, Alexander N; Marzo-Ortega, Helena; Kaur-Papadakis, Daljit; Rehman, Amer

2017-06-01

Magnetic resonance imaging (MRI) is involved in the assessment of axial spondyloarthritis (axSpA); however, anecdotal evidence suggests diverse practice among radiologists. The objective of this study was to describe current practice in the use of MRI for assessment of axSpA by UK radiologists. Six hundred ninety-nine UK radiologists were invited to complete an online survey. Availability of MR scanners, familiarity with axSpA disease-specific lesions, and MRI protocols and definitions of positive sacroiliac joint (SIJ) or spinal MRI were assessed. Two-hundred sixty-nine radiologists (38%) from 131/180 (73%) acute UK National Health Service trusts/health boards responded. MRI waiting times < 2 months were reported by 90% of radiologists. Twenty-nine radiologists (11%) used contrast as standard, 256 (91%) used T1 and short-tau inversion recovery, and 172 (64%) also used T2 sequences. Five percent scanned only SIJ, 33% scanned SIJ and lumbar spine, 29% scanned SIJ and thoracolumbar spine, and 30% scanned SIJ and the whole spine. Mean scan time was 34 min. Eighteen percent did not use the subchondral bone marrow edema of the SIJ to help diagnose axSpA and 18% did not use the inflammatory vertebral corner lesions to assist diagnosis. Awareness of axSpA was reported by 75% of radiologists, and awareness of definitions for positive MRI of SIJ and spine by 31% and 25%, respectively. These data highlight the need for better rheumatology-radiology collaboration on the identification of diagnostic axSpA MRI lesions and support the need for a consensus on the most appropriate MRI protocols for the assessment of axSpA.

Role of serial multiparametric magnetic resonance imaging in prostate cancer active surveillance

PubMed Central

Vos, Larissa J; Janoski, Michele; Wachowicz, Keith; Yahya, Atiyah; Boychak, Oleksandr; Amanie, John; Pervez, Nadeem; Parliament, Matthew B; Pituskin, Edith; Fallone, B Gino; Usmani, Nawaid

2016-01-01

AIM: To examine whether addition of 3T multiparametric magnetic resonance imaging (mpMRI) to an active surveillance protocol could detect aggressive or progressive prostate cancer. METHODS: Twenty-three patients with low risk disease were enrolled on this active surveillance study, all of which had Gleason score 6 or less disease. All patients had clinical assessments, including digital rectal examination and prostate specific antigen (PSA) testing, every 6 mo with annual 3T mpMRI scans with gadolinium contrast and minimum sextant prostate biopsies. The MRI images were anonymized of patient identifiers and clinical information and each scan underwent radiological review without the other results known. Descriptive statistics for demographics and follow-up as well as the sensitivity and specificity of mpMRI to identify prostate cancer and progressive disease were calculated. RESULTS: During follow-up (median 24.8 mo) 11 of 23 patients with low-risk prostate cancer had disease progression and were taken off study to receive definitive treatment. Disease progression was identified through upstaging of Gleason score on subsequent biopsies for all 11 patients with only 2 patients also having a PSA doubling time of less than 2 years. All 23 patients had biopsy confirmed prostate cancer but only 10 had a positive index of suspicion on mpMRI scans at baseline (43.5% sensitivity). Aggressive disease prediction from baseline mpMRI scans had satisfactory specificity (81.8%) but low sensitivity (58.3%). Twenty-two patients had serial mpMRI scans and evidence of disease progression was seen for 3 patients all of whom had upstaging of Gleason score on biopsy (30% specificity and 100% sensitivity). CONCLUSION: Addition of mpMRI imaging in active surveillance decision making may help in identifying aggressive disease amongst men with indolent prostate cancer earlier than traditional methods. PMID:27158428

40 CFR 1620.5 - Administrative claim; evidence and information to be submitted.

Code of Federal Regulations, 2013 CFR

2013-07-01

... relevant medical treatment records, laboratory and other tests, including X-Rays, MRI, CT scans and other... tests including X-Rays, MRI, CT scans and other objective evidence of medical evaluation and diagnosis...

40 CFR 1620.5 - Administrative claim; evidence and information to be submitted.

Code of Federal Regulations, 2012 CFR

2012-07-01

... relevant medical treatment records, laboratory and other tests, including X-Rays, MRI, CT scans and other... tests including X-Rays, MRI, CT scans and other objective evidence of medical evaluation and diagnosis...

40 CFR 1620.5 - Administrative claim; evidence and information to be submitted.

Code of Federal Regulations, 2014 CFR

2014-07-01

... relevant medical treatment records, laboratory and other tests, including X-Rays, MRI, CT scans and other... tests including X-Rays, MRI, CT scans and other objective evidence of medical evaluation and diagnosis...

40 CFR 1620.5 - Administrative claim; evidence and information to be submitted.

Code of Federal Regulations, 2011 CFR

2011-07-01

... relevant medical treatment records, laboratory and other tests, including X-Rays, MRI, CT scans and other... tests including X-Rays, MRI, CT scans and other objective evidence of medical evaluation and diagnosis...

40 CFR 1620.5 - Administrative claim; evidence and information to be submitted.

Code of Federal Regulations, 2010 CFR

2010-07-01

... relevant medical treatment records, laboratory and other tests, including X-Rays, MRI, CT scans and other... tests including X-Rays, MRI, CT scans and other objective evidence of medical evaluation and diagnosis...

Multiple-mouse MRI with multiple arrays of receive coils.

PubMed

Ramirez, Marc S; Esparza-Coss, Emilio; Bankson, James A

2010-03-01

Compared to traditional single-animal imaging methods, multiple-mouse MRI has been shown to dramatically improve imaging throughput and reduce the potentially prohibitive cost for instrument access. To date, up to a single radiofrequency coil has been dedicated to each animal being simultaneously scanned, thus limiting the sensitivity, flexibility, and ultimate throughput. The purpose of this study was to investigate the feasibility of multiple-mouse MRI with a phased-array coil dedicated to each animal. A dual-mouse imaging system, consisting of a pair of two-element phased-array coils, was developed and used to achieve acceleration factors greater than the number of animals scanned at once. By simultaneously scanning two mice with a retrospectively gated cardiac cine MRI sequence, a 3-fold acceleration was achieved with signal-to-noise ratio in the heart that is equivalent to that achieved with an unaccelerated scan using a commercial mouse birdcage coil. (c) 2010 Wiley-Liss, Inc.

Structural and Perfusion Abnormalities of Brain on MRI and Technetium-99m-ECD SPECT in Children With Cerebral Palsy: A Comparative Study.

PubMed

Rana, Kamer Singh; Narwal, Varun; Chauhan, Lokesh; Singh, Giriraj; Sharma, Monica; Chauhan, Suneel

2016-04-01

Cerebral palsy has traditionally been associated with hypoxic ischemic brain damage. This study was undertaken to demonstrate structural and perfusion brain abnormalities. Fifty-six children diagnosed clinically as having cerebral palsy were studied between 1 to 14 years of age and were subjected to 3 Tesla magnetic resonance imaging (MRI). Brain and Technetium-99m-ECD brain single-photon emission computed tomography (SPECT) scan. Male to female ratio was 1.8:1 with a mean age of 4.16 ± 2.274 years. Spastic cerebral palsy was the most common type, observed in 91%. Birth asphyxia was the most common etiology (69.6%). White matter changes (73.2%) such as periventricular leukomalacia and corpus callosal thinning were the most common findings on MRI. On SPECT all cases except one revealed perfusion impairments in different regions of brain. MRI is more sensitive in detecting white matter changes, whereas SPECT is better in detecting cortical and subcortical gray matter abnormalities of perfusion. © The Author(s) 2015.

The experience of patients participating in a small randomised control trial that explored two different interventions to reduce anxiety prior to an MRI scan.

PubMed

Tugwell-Allsup, J; Pritchard, A W

2018-05-01

This paper reports qualitative findings from within a larger randomised control trial where a video clip or telephone conversation with a radiographer was compared to routine appointment letter and information sheet to help alleviate anxiety prior to their MRI scan. Questionnaires consisting of three free-text response questions were administered to all of the 74 patients recruited to the MRI anxiety clinical trial. The questionnaire was designed to establish patients' experiences of the intervention they had received. These questionnaires were administered post-scan. Two participants from each trial arm were also interviewed. A thematic approach was utilised for identifying recurrent categories emerging from the qualitative data which are supported by direct quotations. Participants in the interventional groups commented positively about the provision of pre-MRI scan information they received and this was contrastable with the relatively indifferent responses observed among those who received the standard information letter. Many important themes were identified including the patients needs for clear and simplified information, the experience of anticipation when waiting for the scan, and also the informally acquired information about having an MRI scan i.e. the shared experiences of friends and family. All themes highlighted the need for an inclusive and individually tailored approach to pre-scan information provision. Qualitative data collected throughout the trial is supportive of the statistical findings, where it is asserted that the use of a short video clip or a radiographer having a short conversation with patients before their scan reduces pre-scan anxiety. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Development of representative magnetic resonance imaging-based atlases of the canine brain and evaluation of three methods for atlas-based segmentation.

PubMed

Milne, Marjorie E; Steward, Christopher; Firestone, Simon M; Long, Sam N; O'Brien, Terrence J; Moffat, Bradford A

2016-04-01

To develop representative MRI atlases of the canine brain and to evaluate 3 methods of atlas-based segmentation (ABS). 62 dogs without clinical signs of epilepsy and without MRI evidence of structural brain disease. The MRI scans from 44 dogs were used to develop 4 templates on the basis of brain shape (brachycephalic, mesaticephalic, dolichocephalic, and combined mesaticephalic and dolichocephalic). Atlas labels were generated by segmenting the brain, ventricular system, hippocampal formation, and caudate nuclei. The MRI scans from the remaining 18 dogs were used to evaluate 3 methods of ABS (manual brain extraction and application of a brain shape-specific template [A], automatic brain extraction and application of a brain shape-specific template [B], and manual brain extraction and application of a combined template [C]). The performance of each ABS method was compared by calculation of the Dice and Jaccard coefficients, with manual segmentation used as the gold standard. Method A had the highest mean Jaccard coefficient and was the most accurate ABS method assessed. Measures of overlap for ABS methods that used manual brain extraction (A and C) ranged from 0.75 to 0.95 and compared favorably with repeated measures of overlap for manual extraction, which ranged from 0.88 to 0.97. Atlas-based segmentation was an accurate and repeatable method for segmentation of canine brain structures. It could be performed more rapidly than manual segmentation, which should allow the application of computer-assisted volumetry to large data sets and clinical cases and facilitate neuroimaging research and disease diagnosis.

The interobserver-validated relevance of intervertebral spacer materials in MRI artifacting

PubMed Central

Heidrich, G.; Bruening, T.; Krefft, S.; Buchhorn, G.; Klinger, H.M.

2006-01-01

Intervertebral spacers for anterior spine fusion are made of different materials, such as titanium, carbon or cobalt-chrome, which can affect the post-fusion MRI scans. Implant-related susceptibility artifacts can decrease the quality of MRI scans, thwarting proper evaluation. This cadaver study aimed to demonstrate the extent that implant-related MRI artifacting affects the post-fusion evaluation of intervertebral spacers. In a cadaveric porcine spine, we evaluated the post-implantation MRI scans of three intervertebral spacers that differed in shape, material, surface qualities and implantation technique. A spacer made of human cortical bone was used as a control. The median sagittal MRI slice was divided into 12 regions of interest (ROI). No significant differences were found on 15 different MRI sequences read independently by an interobserver-validated team of specialists (P>0.05). Artifact-affected image quality was rated on a score of 0-1-2. A maximum score of 24 points (100%) was possible. Turbo spin echo sequences produced the best scores for all spacers and the control. Only the control achieved a score of 100%. The carbon, titanium and cobalt-chrome spacers scored 83.3, 62.5 and 50%, respectively. Our scoring system allowed us to create an implant-related ranking of MRI scan quality in reference to the control that was independent of artifact dimensions. The carbon spacer had the lowest percentage of susceptibility artifacts. Even with turbo spin echo sequences, the susceptibility artifacts produced by the metallic spacers showed a high degree of variability. Despite optimum sequencing, implant design and material are relevant factors in MRI artifacting. PMID:16463200

The accuracy of ultrashort echo time MRI sequences for medical additive manufacturing

PubMed Central

Rijkhorst, Erik-Jan; Hofman, Mark; Forouzanfar, Tymour; Wolff, Jan

2016-01-01

Objectives: Additively manufactured bone models, implants and drill guides are becoming increasingly popular amongst maxillofacial surgeons and dentists. To date, such constructs are commonly manufactured using CT technology that induces ionizing radiation. Recently, ultrashort echo time (UTE) MRI sequences have been developed that allow radiation-free imaging of facial bones. The aim of the present study was to assess the feasibility of UTE MRI sequences for medical additive manufacturing (AM). Methods: Three morphologically different dry human mandibles were scanned using a CT and MRI scanner. Additionally, optical scans of all three mandibles were made to acquire a “gold standard”. All CT and MRI scans were converted into Standard Tessellation Language (STL) models and geometrically compared with the gold standard. To quantify the accuracy of the AM process, the CT, MRI and gold-standard STL models of one of the mandibles were additively manufactured, optically scanned and compared with the original gold-standard STL model. Results: Geometric differences between all three CT-derived STL models and the gold standard were <1.0 mm. All three MRI-derived STL models generally presented deviations <1.5 mm in the symphyseal and mandibular area. The AM process introduced minor deviations of <0.5 mm. Conclusions: This study demonstrates that MRI using UTE sequences is a feasible alternative to CT in generating STL models of the mandible and would therefore be suitable for surgical planning and AM. Further in vivo studies are necessary to assess the usability of UTE MRI sequences in clinical settings. PMID:26943179

Clinical safety of 3-T brain magnetic resonance imaging in newborns.

PubMed

Fumagalli, Monica; Cinnante, Claudia Maria; Calloni, Sonia Francesca; Sorrentino, Gabriele; Gorla, Ilaria; Plevani, Laura; Pesenti, Nicola; Sirgiovanni, Ida; Mosca, Fabio; Triulzi, Fabio

2018-03-29

The effects and potential hazards of brain magnetic resonance imaging (MRI) at 3 T in newborns are debated. Assess the impact of 3-T MRI in newborns on body temperature and physiological parameters. Forty-nine newborns, born preterm and at term, underwent 3-T brain MRI at term-corrected age. Rectal and skin temperature, oxygen saturation and heart rate were recorded before, during and after the scan. A statistically significant increase in skin temperature of 0.6 °C was observed at the end of the MRI scan (P<0.01). There was no significant changes in rectal temperature, heart rate or oxygen saturation. Core temperature, heart rate and oxygen saturation in newborns were not affected by 3-T brain MR scanning.

Extraction of Overt Verbal Response from the Acoustic Noise in a Functional Magnetic Resonance Imaging Scan by Use of Segmented Active Noise Cancellation

PubMed Central

Jung, Kwan-Jin; Prasad, Parikshit; Qin, Yulin; Anderson, John R.

2013-01-01

A method to extract the subject's overt verbal response from the obscuring acoustic noise in an fMRI scan is developed by applying active noise cancellation with a conventional MRI microphone. Since the EPI scanning and its accompanying acoustic noise in fMRI are repetitive, the acoustic noise in one time segment was used as a reference noise in suppressing the acoustic noise in subsequent segments. However, the acoustic noise from the scanner was affected by the subject's movements, so the reference noise was adaptively adjusted as the scanner's acoustic properties varied in time. This method was successfully applied to a cognitive fMRI experiment with overt verbal responses. PMID:15723385

Fabrication of Custom-Shaped Grafts for Cartilage Regeneration

PubMed Central

Koo, Seungbum; Hargreaves, Brian A.; Gold, Garry E.; Dragoo, Jason L.

2011-01-01

Transplantation of engineered cartilage grafts is a promising method to treat diseased articular cartilage. The interfacial areas between the graft and the native tissues play an important role in the successful integration of the graft to adjacent native tissues. The purposes of the study were to create a custom shaped graft through 3D tissue shape reconstruction and rapid-prototype molding methods using MRI data, and to test the accuracy of the custom shaped graft against the original anatomical defect. An iatrogenic defect on the distal femur was identified with a 1.5 Tesla MRI and its shape was reconstructed into a three-dimensional (3D) computer model by processing the 3D MRI data. First, the accuracy of the MRI-derived 3D model was tested against a laser-scan based 3D model of the defect. A custom-shaped polyurethane graft was fabricated from the laser-scan based 3D model by creating custom molds through computer aided design and rapid-prototyping methods. The polyurethane tissue was laser-scanned again to calculate the accuracy of this process compared to the original defect. The volumes of the defect models from MRI and laser-scan were 537 mm3 and 405 mm3, respectively, implying that the MRI model was 33% larger than the laser-scan model. The average (±SD) distance deviation of the exterior surface of the MRI model from the laser-scan model was 0.4±0.4 mm. The custom-shaped tissue created from the molds was qualitatively very similar to the original shape of the defect. The volume of the custom-shaped cartilage tissue was 463 mm3 which was 15% larger than the laser-scan model. The average (±SD) distance deviation between the two models was 0.04±0.19 mm. Custom-shaped engineered grafts can be fabricated from standard sequence 3-D MRI data with the use of CAD and rapid-prototyping technology, which may help solve the interfacial problem between native cartilage and graft, if the grafts are custom made for the specific defect. The major source of error in fabricating a 3D custom shaped cartilage graft appears to be the accuracy of a MRI data itself; however, the precision of the model is expected to increase by the utilization of advanced MR sequences with higher magnet strengths. PMID:21058268

Non-invasive imaging of transplanted human neural stem cells and ECM scaffold remodeling in the stroke-damaged rat brain by 19F- and diffusion-MRI

PubMed Central

Bible, Ellen; Dell’Acqua, Flavio; Solanky, Bhavana; Balducci, Anthony; Crapo, Peter; Badylak, Stephen F.; Ahrens, Eric T.; Modo, Michel

2012-01-01

Transplantation of human neural stem cells (hNSCs) is emerging as a viable treatment for stroke related brain injury. However, intraparenchymal grafts do not regenerate lost tissue, but rather integrate into the host parenchyma without significantly affecting the lesion cavity. Providing a structural support for the delivered cells appears important for cell based therapeutic approaches. The non-invasive monitoring of therapeutic methods would provide valuable information regarding therapeutic strategies but remains a challenge. Labeling transplanted cells with metal-based 1H-magnetic resonance imaging (MRI) contrast agents affects the visualization of the lesion cavity. Herein, we demonstrate that a 19F-MRI contrast agent can adequately monitor the distribution of transplanted cells, whilst allowing an evaluation of the lesion cavity and the formation of new tissue on 1H-MRI scans. Twenty percent of cells labeled with the 19F-agent were of host origin, potentially reflecting the re-uptake of label from dead transplanted cells. Both T2- and diffusion-weighted MRI scans indicated that transplantation of hNSCs suspended in a gel form of a xenogeneic extracellular matrix (ECM) bioscaffold resulted in uniformly distributed cells throughout the lesion cavity. However, diffusion MRI indicated that the injected materials did not yet establish diffusion barriers (i.e. cellular network, fiber tracts) normally found within striatal tissue. The ECM bioscaffold therefore provides an important support to hNSCs for the creation of de novo tissue and multi-nuclei MRI represents an adept method for the visualization of some aspects of this process. However, significant developments of both the transplantation paradigm, as well as regenerative imaging, are required to successfully create new tissue in the lesion cavity and to monitor this process non-invasively. PMID:22244696

Is magnetic resonance imaging in addition to a computed tomographic scan necessary to identify clinically significant cervical spine injuries in obtunded blunt trauma patients?

PubMed

Fisher, Brian M; Cowles, Steven; Matulich, Jennifer R; Evanson, Bradley G; Vega, Diana; Dissanaike, Sharmila

2013-12-01

Guidelines are in place directing the clearance of the cervical spine in patients who are awake, alert, and oriented, but a gold standard has not been recognized for patients who are obtunded. Our study is designed to determine if magnetic resonance imaging (MRI) detects clinically significant injuries not seen on computed tomographic (CT) scans. The trauma registry was used to identify and retrospectively review medical records of blunt trauma patients from January 1, 2005, to March 30, 2012. Only obtunded patients with a CT scan and MRI of the cervical spine were included. The study cohort consisted of 277 patients. In 13 (5%) patients, MRI detected clinically significant cervical spine injuries that were missed by CT scans, and in 7 (3%) these injuries required intervention. The number needed to screen with MRI to prevent 1 missed injury was 21. The findings suggest that the routine use of MRI in clearing the cervical spine in the obtunded blunt trauma patient. Copyright © 2013 Elsevier Inc. All rights reserved.

3 Tesla MRI of patients with a vagus nerve stimulator: initial experience using a T/R head coil under controlled conditions.

PubMed

Gorny, Krzysztof R; Bernstein, Matt A; Watson, Robert E

2010-02-01

To assess safety of clinical MRI of the head in patients with implanted model 100, 102, and 103 vagus nerve stimulation (VNS) Therapy Systems (Cyberonics, Inc., Houston, TX) in 3.0 Tesla MRI (GE Healthcare, Milwaukee, WI). The distributions of the radiofrequency B(1) (+)-field produced by the clinically used transmit/receive (T/R) head coil (Advanced Imaging Research Incorporated, Cleveland, OH) and body coil were measured in a head and shoulders phantom. These measurements were supplemented by temperature measurements on the lead tips and the implantable pulse generator (IPG) of the VNS devices in a head and torso phantom with the same two coils. Clinical 3T MRI head scans were then acquired under highly controlled conditions in a series of 17 patients implanted with VNS. Phantom studies showed only weak B(1) (+) fields at the location of the VNS IPG and leads for MRI scans using the T/R head coil. The MRI-related heating on a VNS scanned in vitro at 3T was also found to be minimal (0.4-0.8 degrees C at the leads, negligible at the IPG). The patient MRI examinations were completed successfully without any adverse incidents. No patient reported any heating, discomfort, or any other unusual sensation. Safe clinical MRI head scanning of patients with implanted VNS is shown to be feasible on a GE Signa Excite 3T MRI system using one specific T/R head coil. These results apply to this particular MRI system configuration. Extrapolation or generalization of these results to more general or less controlled imaging situations without supporting data of safety is highly discouraged.

Functional magnetic resonance imaging in a low-field intraoperative scanner.

PubMed

Schulder, Michael; Azmi, Hooman; Biswal, Bharat

2003-01-01

Functional magnetic resonance imaging (fMRI) has been used for preoperative planning and intraoperative surgical navigation. However, most experience to date has been with preoperative images acquired on high-field echoplanar MRI units. We explored the feasibility of acquiring fMRI of the motor cortex with a dedicated low-field intraoperative MRI (iMRI). Five healthy volunteers were scanned with the 0.12-tesla PoleStar N-10 iMRI (Odin Medical Technologies, Israel). A finger-tapping motor paradigm was performed with sequential scans, acquired alternately at rest and during activity. In addition, scans were obtained during breath holding alternating with normal breathing. The same paradigms were repeated using a 3-tesla MRI (Siemens Corp., Allandale, N.J., USA). Statistical analysis was performed offline using cross-correlation and cluster techniques. Data were resampled using the 'jackknife' process. The location, number of activated voxels and degrees of statistical significance between the two scanners were compared. With both the 0.12- and 3-tesla imagers, motor cortex activation was seen in all subjects to a significance of p < 0.02 or greater. No clustered pixels were seen outside the sensorimotor cortex. The resampled correlation coefficients were normally distributed, with a mean of 0.56 for both the 0.12- and 3-tesla scanners (standard deviations 0.11 and 0.08, respectively). The breath holding paradigm confirmed that the expected diffuse activation was seen on 0.12- and 3-tesla scans. Accurate fMRI with a low-field iMRI is feasible. Such data could be acquired immediately before or even during surgery. This would increase the utility of iMRI and allow for updated intraoperative functional imaging, free of the limitations of brain shift. Copyright 2003 S. Karger AG, Basel

Patch-based generation of a pseudo CT from conventional MRI sequences for MRI-only radiotherapy of the brain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreasen, Daniel, E-mail: dana@dtu.dk; Van Leemput, Koen; Hansen, Rasmus H.

Purpose: In radiotherapy (RT) based on magnetic resonance imaging (MRI) as the only modality, the information on electron density must be derived from the MRI scan by creating a so-called pseudo computed tomography (pCT). This is a nontrivial task, since the voxel-intensities in an MRI scan are not uniquely related to electron density. To solve the task, voxel-based or atlas-based models have typically been used. The voxel-based models require a specialized dual ultrashort echo time MRI sequence for bone visualization and the atlas-based models require deformable registrations of conventional MRI scans. In this study, we investigate the potential of amore » patch-based method for creating a pCT based on conventional T{sub 1}-weighted MRI scans without using deformable registrations. We compare this method against two state-of-the-art methods within the voxel-based and atlas-based categories. Methods: The data consisted of CT and MRI scans of five cranial RT patients. To compare the performance of the different methods, a nested cross validation was done to find optimal model parameters for all the methods. Voxel-wise and geometric evaluations of the pCTs were done. Furthermore, a radiologic evaluation based on water equivalent path lengths was carried out, comparing the upper hemisphere of the head in the pCT and the real CT. Finally, the dosimetric accuracy was tested and compared for a photon treatment plan. Results: The pCTs produced with the patch-based method had the best voxel-wise, geometric, and radiologic agreement with the real CT, closely followed by the atlas-based method. In terms of the dosimetric accuracy, the patch-based method had average deviations of less than 0.5% in measures related to target coverage. Conclusions: We showed that a patch-based method could generate an accurate pCT based on conventional T{sub 1}-weighted MRI sequences and without deformable registrations. In our evaluations, the method performed better than existing voxel-based and atlas-based methods and showed a promising potential for RT of the brain based only on MRI.« less

Tensor Based Representation and Analysis of Diffusion-Weighted Magnetic Resonance Images

ERIC Educational Resources Information Center

Barmpoutis, Angelos

2009-01-01

Cartesian tensor bases have been widely used to model spherical functions. In medical imaging, tensors of various orders can approximate the diffusivity function at each voxel of a diffusion-weighted MRI data set. This approximation produces tensor-valued datasets that contain information about the underlying local structure of the scanned tissue.…

A Double Blind Trial of Divalproex Sodium for Affective Liability and Alcohol Use Following Traumatic Brain Injury

DTIC Science & Technology

2016-01-01

Pennsylvania, we completed computerized volumetric analysis of the structural MRI scans of the brain collected from the study subjects, using the... pharmacological management. Brain Injury 2001;15(2):139-48. 07. Wroblewski BA, Joseph AB, Kupfer J, Kalliel K. Effectiveness of valproic acid on

Reliability measures of functional magnetic resonance imaging in a longitudinal evaluation of mild cognitive impairment.

PubMed

Zanto, Theodore P; Pa, Judy; Gazzaley, Adam

2014-01-01

As the aging population grows, it has become increasingly important to carefully characterize amnestic mild cognitive impairment (aMCI), a preclinical stage of Alzheimer's disease (AD). Functional magnetic resonance imaging (fMRI) is a valuable tool for monitoring disease progression in selectively vulnerable brain regions associated with AD neuropathology. However, the reliability of fMRI data in longitudinal studies of older adults with aMCI is largely unexplored. To address this, aMCI participants completed two visual working tasks, a Delayed-Recognition task and a One-Back task, on three separate scanning sessions over a three-month period. Test-retest reliability of the fMRI blood oxygen level dependent (BOLD) activity was assessed using an intraclass correlation (ICC) analysis approach. Results indicated that brain regions engaged during the task displayed greater reliability across sessions compared to regions that were not utilized by the task. During task-engagement, differential reliability scores were observed across the brain such that the frontal lobe, medial temporal lobe, and subcortical structures exhibited fair to moderate reliability (ICC=0.3-0.6), while temporal, parietal, and occipital regions exhibited moderate to good reliability (ICC=0.4-0.7). Additionally, reliability across brain regions was more stable when three fMRI sessions were used in the ICC calculation relative to two fMRI sessions. In conclusion, the fMRI BOLD signal is reliable across scanning sessions in this population and thus a useful tool for tracking longitudinal change in observational and interventional studies in aMCI. © 2013.

A Preliminary Experience with Use of Intraoperative Magnetic Resonance Imaging in Thalamic Glioma Surgery: A Case Series of 38 Patients.

PubMed

Zheng, Xuan; Xu, Xinghua; Zhang, Hui; Wang, Qun; Ma, Xiaodong; Chen, Xiaolei; Sun, Guochen; Zhang, Jiashu; Jiang, Jinli; Xu, Bainan; Zhang, Jun

2016-05-01

Thalamic gliomas are rare tumors that constitute 1%-5% of all central nervous system tumors. Despite advanced techniques and equipment, surgical resection remains challenging because of the vital structures adjacent to the tumor. Intraoperative magnetic resonance imaging (MRI) might play an active role during brain tumor surgery because it compensates for brain shift or operation-induced hemorrhage, which are challenging issues for neurosurgeons. We reviewed 38 patients treated surgically under intraoperative MRI guidance between January 2008 and July 2015 at our center. Preoperative, intraoperative, and postoperative MRI scans were reviewed. Preoperative and postoperative motor power, morbidity and mortality, resection rate, surgical approach, pathologic results, and patient demographics were also reviewed. Mean patient age was 37 years ± 18; 12 patients were included in the low-grade group, and 26 patients were included in the high-grade group. Under intraoperative MRI guidance, the gross total resection rate was increased from 16 (42.1%) to 26 (68.4%), and the near-total or subtotal resection rate was increased from 5 (13.2%) to 9 (23.7%). Hematoma formation was discovered in 3 patients on intraoperative MRI scan; each patient underwent a hemostatic operation immediately. With improvements in neurosurgical techniques and equipment, surgical resection is considered feasible in patients with thalamic gliomas. Intraoperative MRI may be helpful in achieving the maximal resection rate with minimal surgical-related morbidity. However, because of severe disease progression, the overall prognosis is unfavorable. Copyright © 2016 Elsevier Inc. All rights reserved.

Spirometer-controlled cine magnetic resonance imaging used to diagnose tracheobronchomalacia in paediatric patients.

PubMed

Ciet, Pierluigi; Wielopolski, Piotr; Manniesing, Rashindra; Lever, Sandra; de Bruijne, Marleen; Morana, Giovanni; Muzzio, Pier Carlo; Lequin, Maarten H; Tiddens, Harm A W M

2014-01-01

Tracheobronchomalacia (TBM) is defined as an excessive collapse of the intrathoracic trachea. Bronchoscopy is the gold standard for diagnosing TBM; however it has major disadvantages, such as general anaesthesia. Cine computed tomography (CT) is a noninvasive alternative used to diagnose TBM, but its use in children is restricted by ionising radiation. Our aim was to evaluate the feasibility of spirometer-controlled cine magnetic resonance imaging (MRI) as an alternative to cine-CT in a retrospective study. 12 children with a mean age (range) of 12 years (7-17 years), suspected of having TBM, underwent cine-MRI. Static scans were acquired at end-inspiration and expiration covering the thorax using a three-dimensional spoiled gradient echo sequence. Three-dimensional dynamic scans were performed covering only the central airways. TBM was defined as a decrease of the trachea or bronchi diameter >50% at end-expiration in the static and dynamic scans. The success rate of the cine-MRI protocol was 92%. Cine-MRI was compared with bronchoscopy or chest CT in seven subjects. TBM was diagnosed by cine-MRI in seven (58%) out of 12 children and was confirmed by bronchoscopy or CT. In four patients, cine-MRI demonstrated tracheal narrowing that was not present in the static scans. Spirometer controlled cine-MRI is a promising technique to assess TBM in children and has the potential to replace bronchoscopy.

High-resolution whole-brain DCE-MRI using constrained reconstruction: Prospective clinical evaluation in brain tumor patients.

PubMed

Guo, Yi; Lebel, R Marc; Zhu, Yinghua; Lingala, Sajan Goud; Shiroishi, Mark S; Law, Meng; Nayak, Krishna

2016-05-01

To clinically evaluate a highly accelerated T1-weighted dynamic contrast-enhanced (DCE) MRI technique that provides high spatial resolution and whole-brain coverage via undersampling and constrained reconstruction with multiple sparsity constraints. Conventional (rate-2 SENSE) and experimental DCE-MRI (rate-30) scans were performed 20 minutes apart in 15 brain tumor patients. The conventional clinical DCE-MRI had voxel dimensions 0.9 × 1.3 × 7.0 mm(3), FOV 22 × 22 × 4.2 cm(3), and the experimental DCE-MRI had voxel dimensions 0.9 × 0.9 × 1.9 mm(3), and broader coverage 22 × 22 × 19 cm(3). Temporal resolution was 5 s for both protocols. Time-resolved images and blood-brain barrier permeability maps were qualitatively evaluated by two radiologists. The experimental DCE-MRI scans showed no loss of qualitative information in any of the cases, while achieving substantially higher spatial resolution and whole-brain spatial coverage. Average qualitative scores (from 0 to 3) were 2.1 for the experimental scans and 1.1 for the conventional clinical scans. The proposed DCE-MRI approach provides clinically superior image quality with higher spatial resolution and coverage than currently available approaches. These advantages may allow comprehensive permeability mapping in the brain, which is especially valuable in the setting of large lesions or multiple lesions spread throughout the brain.

Ameliorating slice gaps in multislice magnetic resonance images: an interpolation scheme.

PubMed

Kashou, Nasser H; Smith, Mark A; Roberts, Cynthia J

2015-01-01

Standard two-dimension (2D) magnetic resonance imaging (MRI) clinical acquisition protocols utilize orthogonal plane images which contain slice gaps (SG). The purpose of this work is to introduce a novel interpolation method for these orthogonal plane MRI 2D datasets. Three goals can be achieved: (1) increasing the resolution based on a priori knowledge of scanning protocol, (2) ameliorating the loss of data as a result of SG and (3) reconstructing a three-dimension (3D) dataset from 2D images. MRI data was collected using a 3T GE scanner and simulated using Matlab. The procedure for validating the MRI data combination algorithm was performed using a Shepp-Logan and a Gaussian phantom in both 2D and 3D of varying matrix sizes (64-512), as well as on one MRI dataset of a human brain and on an American College of Radiology magnetic resonance accreditation phantom. The squared error and mean squared error were computed in comparing this scheme to common interpolating functions employed in MR consoles and workstations. The mean structure similarity matrix was computed in 2D as a means of qualitative image assessment. Additionally, MRI scans were used for qualitative assessment of the method. This new scheme was consistently more accurate than upsampling each orientation separately and averaging the upsampled data. An efficient new interpolation approach to resolve SG was developed. This scheme effectively fills in the missing data points by using orthogonal plane images. To date, there have been few attempts to combine the information of three MRI plane orientations using brain images. This has specific applications for clinical MRI, functional MRI, diffusion-weighted imaging/diffusion tensor imaging and MR angiography where 2D slice acquisition are used. In these cases, the 2D data can be combined using our method in order to obtain 3D volume.

The Marburg-Münster Affective Disorders Cohort Study (MACS): A quality assurance protocol for MR neuroimaging data.

PubMed

Vogelbacher, Christoph; Möbius, Thomas W D; Sommer, Jens; Schuster, Verena; Dannlowski, Udo; Kircher, Tilo; Dempfle, Astrid; Jansen, Andreas; Bopp, Miriam H A

2018-05-15

Large, longitudinal, multi-center MR neuroimaging studies require comprehensive quality assurance (QA) protocols for assessing the general quality of the compiled data, indicating potential malfunctions in the scanning equipment, and evaluating inter-site differences that need to be accounted for in subsequent analyses. We describe the implementation of a QA protocol for functional magnet resonance imaging (fMRI) data based on the regular measurement of an MRI phantom and an extensive variety of currently published QA statistics. The protocol is implemented in the MACS (Marburg-Münster Affective Disorders Cohort Study, http://for2107.de/), a two-center research consortium studying the neurobiological foundations of affective disorders. Between February 2015 and October 2016, 1214 phantom measurements have been acquired using a standard fMRI protocol. Using 444 healthy control subjects which have been measured between 2014 and 2016 in the cohort, we investigate the extent of between-site differences in contrast to the dependence on subject-specific covariates (age and sex) for structural MRI, fMRI, and diffusion tensor imaging (DTI) data. We show that most of the presented QA statistics differ severely not only between the two scanners used for the cohort but also between experimental settings (e.g. hardware and software changes), demonstrate that some of these statistics depend on external variables (e.g. time of day, temperature), highlight their strong dependence on proper handling of the MRI phantom, and show how the use of a phantom holder may balance this dependence. Site effects, however, do not only exist for the phantom data, but also for human MRI data. Using T1-weighted structural images, we show that total intracranial (TIV), grey matter (GMV), and white matter (WMV) volumes significantly differ between the MR scanners, showing large effect sizes. Voxel-based morphometry (VBM) analyses show that these structural differences observed between scanners are most pronounced in the bilateral basal ganglia, thalamus, and posterior regions. Using DTI data, we also show that fractional anisotropy (FA) differs between sites in almost all regions assessed. When pooling data from multiple centers, our data show that it is a necessity to account not only for inter-site differences but also for hardware and software changes of the scanning equipment. Also, the strong dependence of the QA statistics on the reliable placement of the MRI phantom shows that the use of a phantom holder is recommended to reduce the variance of the QA statistics and thus to increase the probability of detecting potential scanner malfunctions. Copyright © 2018 Elsevier Inc. All rights reserved.

[Magnetic resonance imaging in patients with implantable devices for treatment of disturbed heart rhythm: review of the current situation].

PubMed

Sviridova, A A

The question of the possibility of MRI scanning in patients with cardiac implantable electronic devices (CIED) appeared simultaneously with the introduction of MRI in clinical practice. A lot of in-vitro, in-vivo and clinical researches were performed to estimate wat going on with CIED in strong magnetic field and is it possible to perform some unified protocol of safe MRI-scanning for these patients. Recommendations were provided, but not for the wide practice. MRI remained strongly contraindicated for CIED patient. To meet the clinical need CIEM manufacturers changed the design of devices to made them MRI-compatible, including reducing of ferromagnetic components, additional filters, new software. Lead coil design was changed as well to minimize lead heating and electrical current induction. Now all leaders of CIED industry have in their portfolio all types of MRI-conditional implanted cardiac rhythm management devices (pacemakers, ICDs, CRTs). "Conditional" means MRI scanning can be done only under specific condition. For MRI device and lead in one system have to be from the same manufacturer. Now, if you need to implant the device, you must proceed from the fact that the patient is more likely to need an MRI in the future and choose the appropriate model, not forgetting that the electrodes should also be MRI-compatible.

Advances in diffusion MRI acquisition and processing in the Human Connectome Project

PubMed Central

Sotiropoulos, Stamatios N; Jbabdi, Saad; Xu, Junqian; Andersson, Jesper L; Moeller, Steen; Auerbach, Edward J; Glasser, Matthew F; Hernandez, Moises; Sapiro, Guillermo; Jenkinson, Mark; Feinberg, David A; Yacoub, Essa; Lenglet, Christophe; Ven Essen, David C; Ugurbil, Kamil; Behrens, Timothy EJ

2013-01-01

The Human Connectome Project (HCP) is a collaborative 5-year effort to map human brain connections and their variability in healthy adults. A consortium of HCP investigators will study a population of 1200 healthy adults using multiple imaging modalities, along with extensive behavioral and genetic data. In this overview, we focus on diffusion MRI (dMRI) and the structural connectivity aspect of the project. We present recent advances in acquisition and processing that allow us to obtain very high-quality in-vivo MRI data, while enabling scanning of a very large number of subjects. These advances result from 2 years of intensive efforts in optimising many aspects of data acquisition and processing during the piloting phase of the project. The data quality and methods described here are representative of the datasets and processing pipelines that will be made freely available to the community at quarterly intervals, beginning in 2013. PMID:23702418

Morphometricity as a measure of the neuroanatomical signature of a trait.

PubMed

Sabuncu, Mert R; Ge, Tian; Holmes, Avram J; Smoller, Jordan W; Buckner, Randy L; Fischl, Bruce

2016-09-27

Complex physiological and behavioral traits, including neurological and psychiatric disorders, often associate with distributed anatomical variation. This paper introduces a global metric, called morphometricity, as a measure of the anatomical signature of different traits. Morphometricity is defined as the proportion of phenotypic variation that can be explained by macroscopic brain morphology. We estimate morphometricity via a linear mixed-effects model that uses an anatomical similarity matrix computed based on measurements derived from structural brain MRI scans. We examined over 3,800 unique MRI scans from nine large-scale studies to estimate the morphometricity of a range of phenotypes, including clinical diagnoses such as Alzheimer's disease, and nonclinical traits such as measures of cognition. Our results demonstrate that morphometricity can provide novel insights about the neuroanatomical correlates of a diverse set of traits, revealing associations that might not be detectable through traditional statistical techniques.

Morphometricity as a measure of the neuroanatomical signature of a trait

PubMed Central

Sabuncu, Mert R.; Ge, Tian; Holmes, Avram J.; Smoller, Jordan W.; Buckner, Randy L.; Fischl, Bruce

2016-01-01

Complex physiological and behavioral traits, including neurological and psychiatric disorders, often associate with distributed anatomical variation. This paper introduces a global metric, called morphometricity, as a measure of the anatomical signature of different traits. Morphometricity is defined as the proportion of phenotypic variation that can be explained by macroscopic brain morphology. We estimate morphometricity via a linear mixed-effects model that uses an anatomical similarity matrix computed based on measurements derived from structural brain MRI scans. We examined over 3,800 unique MRI scans from nine large-scale studies to estimate the morphometricity of a range of phenotypes, including clinical diagnoses such as Alzheimer’s disease, and nonclinical traits such as measures of cognition. Our results demonstrate that morphometricity can provide novel insights about the neuroanatomical correlates of a diverse set of traits, revealing associations that might not be detectable through traditional statistical techniques. PMID:27613854

HEAVY PRENATAL ALCOHOL EXPOSURE IS RELATED TO SMALLER CORPUS CALLOSUM IN NEWBORN MRI SCANS

PubMed Central

Jacobson, Sandra W.; Jacobson, Joseph L.; Molteno, Christopher D.; Warton, Christopher M. R.; Wintermark, Pia; Hoyme, H Eugene; De Jong, Greetje; Taylor, Paul; Warton, Fleur; Lindinger, Nadine M.; Carter, R. Colin; Dodge, Neil C.; Grant, Ellen; Warfield, Simon K.; Zöllei, Lilla; van der Kouwe, André J. W.; Meintjes, Ernesta M.

2017-01-01

Background MRI studies have consistently demonstrated disproportionately smaller corpus callosa in individuals with a history of prenatal alcohol exposure but have not previously examined the feasibility of detecting this effect in infants. Tissue segmentation of the newborn brain is challenging because analysis techniques developed for the adult brain are not directly transferable, and segmentation for cerebral morphometry is difficult in neonates, due to the latter’s incomplete myelination. This study is the first to use volumetric structural MRI to investigate prenatal alcohol exposure effects in newborns using manual tracing and to examine the cross-sectional area of the corpus callosum (CC). Methods 43 nonsedated infants born to 32 Cape Coloured heavy drinkers and 11 controls recruited prospectively during pregnancy were scanned using a custom-designed birdcage coil for infants, which increases signal-to-noise ratio almost two-fold compared to the standard head coil. Alcohol use was ascertained prospectively during pregnancy, and FASD diagnosis was conducted by expert dysmorphologists. Data were acquired using a multi-echo FLASH protocol adapted for newborns, and a knowledge-based procedure was used to hand-segment the neonatal brains. Results CC was disproportionately smaller in alcohol-exposed neonates than controls after controlling for intracranial volume. By contrast, CC area was unrelated to infant sex, gestational age, age at scan, or maternal smoking, marijuana, or methamphetamine use during pregnancy. Conclusions Given that midline craniofacial anomalies have been recognized as a hallmark of FAS in humans and animal models since this syndrome was first identified, the CC deficit identified here in newborns may support early identification of a range of midline structural impairments. Smaller CC during the newborn period may provide an early indicator of fetal alcohol-related cognitive deficits that have been linked to this critically important brain structure in childhood and adolescence. PMID:28247416

Intraoperative Magnetic Resonance Imaging in Skull Base Surgery: A Review of 71 Consecutive Cases.

PubMed

Ashour, Ramsey; Reintjes, Stephen; Park, Michael S; Sivakanthan, Sananthan; van Loveren, Harry; Agazzi, Siviero

2016-09-01

Although intraoperative magnetic resonance imaging (iMRI) increasingly is used during glioma resection, its role in skull base surgery has not been well documented. In this study, we evaluate our experience with iMRI for skull base surgery. Medical records were reviewed retrospectively on all neurosurgical cases performed at our institution in the IMRIS iMRI suite between April 2014 and July 2015. During the study period, the iMRI suite was used for 71 skull base tumors. iMRI was performed in 23 of 71 cases. Additional tumor resection was pursued after scanning in 7 of 23 patients. There was a significant difference in procedure length between the scanned versus nonscanned groups, and this was likely attributable to a greater proportion of petroclival meningiomas in the scanned group. Further analyses revealed significant increases in procedure length for the following scanned subgroups: anterolateral approach, anterolateral and petroclival lesion locations, and meningiomas. The rate of non-neurologic complications was significantly greater in the scanned group, particularly for patients with tumors >3 cm. Despite the unique challenges associated with skull base tumor surgery, iMRI can be safely obtained while adding a modest although not prohibitive amount of time to the procedure. The immediate evidence of residual tumor with a patient still in position to have additional resection may influence the surgeon to alter the surgical plan and attempt further resection in a critical area. Copyright © 2016 Elsevier Inc. All rights reserved.

A multi-layer MRI description of Parkinson's disease

NASA Astrophysics Data System (ADS)

La Rocca, M.; Amoroso, N.; Lella, E.; Bellotti, R.; Tangaro, S.

2017-09-01

Magnetic resonance imaging (MRI) along with complex network is currently one of the most widely adopted techniques for detection of structural changes in neurological diseases, such as Parkinson's Disease (PD). In this paper, we present a digital image processing study, within the multi-layer network framework, combining more classifiers to evaluate the informative power of the MRI features, for the discrimination of normal controls (NC) and PD subjects. We define a network for each MRI scan; the nodes are the sub-volumes (patches) the images are divided into and the links are defined using the Pearson's pairwise correlation between patches. We obtain a multi-layer network whose important network features, obtained with different feature selection methods, are used to feed a supervised multi-level random forest classifier which exploits this base of knowledge for accurate classification. Method evaluation has been carried out using T1 MRI scans of 354 individuals, including 177 PD subjects and 177 NC from the Parkinson's Progression Markers Initiative (PPMI) database. The experimental results demonstrate that the features obtained from multiplex networks are able to accurately describe PD patterns. Besides, also if a privileged scale for studying PD disease exists, exploring the informative content of more scales leads to a significant improvement of the performances in the discrimination between disease and healthy subjects. In particular, this method gives a comprehensive overview of brain regions statistically affected by the disease, an additional value to the presented study.

MRI micturating urethrography for improved urethral delineation in prostate radiotherapy planning: a case study

NASA Astrophysics Data System (ADS)

Rai, Robba; Sidhom, Mark; Lim, Karen; Ohanessian, Lucy; Liney, Gary P.

2017-04-01

Stereotactic ablative body radiotherapy is used in prostate cancer to deliver a high dose of radiation to the tumour over a small number of treatments. This involves the simulation of the patient using both CT and MRI. Current practice is to insert an indwelling catheter (IDC) during CT to assist with visualisation of the urethra and subsequently minimise dose to this highly critical structure. However, this procedure is invasive and has an associated risk of infection. This is a case study, which demonstrates our initial experience of using a real-time non-invasive MRI technique to replace the use of IDC for prostate cancer patients. The patient was scanned on a dedicated 3T MRI and was instructed to micturate in their own time whereupon a sagittal T2 weighted HASTE sequence was acquired every 5 s. This was subsequently followed by T2 weighted axial imaging at the level of mid prostate to provide improved urethral definition. Acquired images showed bladder voidance in real-time and an increase in signal intensity in the proximal urethra post voiding allowing for delineation of the urethra. The dimension and shape of the proximal urethra was well visualised and accumulation time of urine in the urethra was sufficient to enable optimum timing of the scanning technique. We have presented for the first time a micturating urethography technique using MRI, which has allowed us to visualise the urethra without contrast and with minimal invasiveness to the patient.

Magnetic resonance imaging-conditional devices: Luxury or real clinical need?

PubMed

Mavrogeni, Sophie I; Poulos, George; Kolovou, Genovefa; Theodorakis, George

Although the risk of MRI scanning on patients with conventional devices is lower than initially thought, the patient's safety can only be guaranteed when using MRI-conditional devices. The most important modifications in MRI-conditional devices include a) Reduction in ferromagnetic components to reduce magnetic attraction and susceptibility artifacts; b) Replacement of the reed switch by a Hall sensor in order to avoid unpredictable reed switch behavior; c) Lead coil design to minimize lead heating and electrical current induction; d) Filter circuitry to prevent damage to the internal power supply; and e) Dedicated pacemaker programming to prevent inappropriate pacemaker inhibition and competing rhythms. Although many companies claim to have MRI-conditional devices, adoption in clinical practice is limited because a) Not all companies have MRI-conditional devices approved for both 1.5 and 3T; b) Not all companies offer the option of unlimited MRI scanning (without an exclusion zone in the thorax); c) Certain companies allow only a 30-min MRI scanning and only in afebrile patients; and d) Despite having MRI-conditional pacemakers, certain companies do not have MRI-conditional defibrillators and CRT systems. It is clear that this new technology opens the door for MRI to a growing number of patients; however, the widespread adoption of MRI-conditional devices will depend on real-life issues, such as cost, clinical indications for such a device and the permanent education of health care professionals. Copyright © 2017 Hellenic Society of Cardiology. Published by Elsevier B.V. All rights reserved.

Haptic fMRI: Reliability and performance of electromagnetic haptic interfaces for motion and force neuroimaging experiments.

PubMed

Menon, Samir; Zhu, Jack; Goyal, Deeksha; Khatib, Oussama

2017-07-01

Haptic interfaces compatible with functional magnetic resonance imaging (Haptic fMRI) promise to enable rich motor neuroscience experiments that study how humans perform complex manipulation tasks. Here, we present a large-scale study (176 scans runs, 33 scan sessions) that characterizes the reliability and performance of one such electromagnetically actuated device, Haptic fMRI Interface 3 (HFI-3). We outline engineering advances that ensured HFI-3 did not interfere with fMRI measurements. Observed fMRI temporal noise levels with HFI-3 operating were at the fMRI baseline (0.8% noise to signal). We also present results from HFI-3 experiments demonstrating that high resolution fMRI can be used to study spatio-temporal patterns of fMRI blood oxygenation dependent (BOLD) activation. These experiments include motor planning, goal-directed reaching, and visually-guided force control. Observed fMRI responses are consistent with existing literature, which supports Haptic fMRI's effectiveness at studying the brain's motor regions.

Optimising EEG-fMRI for Localisation of Focal Epilepsy in Children.

PubMed

Centeno, Maria; Tierney, Tim M; Perani, Suejen; Shamshiri, Elhum A; StPier, Kelly; Wilkinson, Charlotte; Konn, Daniel; Banks, Tina; Vulliemoz, Serge; Lemieux, Louis; Pressler, Ronit M; Clark, Christopher A; Cross, J Helen; Carmichael, David W

2016-01-01

Early surgical intervention in children with drug resistant epilepsy has benefits but requires using tolerable and minimally invasive tests. EEG-fMRI studies have demonstrated good sensitivity for the localization of epileptic focus but a poor yield although the reasons for this have not been systematically addressed. While adults EEG-fMRI studies are performed in the "resting state"; children are commonly sedated however, this has associated risks and potential confounds. In this study, we assessed the impact of the following factors on the tolerability and results of EEG-fMRI in children: viewing a movie inside the scanner; movement; occurrence of interictal epileptiform discharges (IED); scan duration and design efficiency. This work's motivation is to optimize EEG-fMRI parameters to make this test widely available to paediatric population. Forty-six children with focal epilepsy and 20 controls (6-18) underwent EEG-fMRI. For two 10 minutes sessions subjects were told to lie still with eyes closed, as it is classically performed in adult studies ("rest sessions"), for another two sessions, subjects watched a child friendly stimulation i.e. movie ("movie sessions"). IED were mapped with EEG-fMRI for each session and across sessions. The resulting maps were classified as concordant/discordant with the presumed epileptogenic focus for each subject. Movement increased with scan duration, but the movie reduced movement by ~40% when played within the first 20 minutes. There was no effect of movie on the occurrence of IED, nor in the concordance of the test. Ability of EEG-fMRI to map the epileptogenic region was similar for the 20 and 40 minute scan durations. Design efficiency was predictive of concordance. A child friendly natural stimulus improves the tolerability of EEG-fMRI and reduces in-scanner movement without having an effect on IED occurrence and quality of EEG-fMRI maps. This allowed us to scan children as young as 6 and obtain localising information without sedation. Our data suggest that ~20 minutes is the optimal length of scanning for EEG-fMRI studies in children with frequent IED. The efficiency of the fMRI design derived from spontaneous IED generation is an important factor for producing concordant results.

Prediction of individual clinical scores in patients with Parkinson's disease using resting-state functional magnetic resonance imaging.

PubMed

Hou, YanBing; Luo, ChunYan; Yang, Jing; Ou, RuWei; Song, Wei; Wei, QianQian; Cao, Bei; Zhao, Bi; Wu, Ying; Shang, Hui-Fang; Gong, QiYong

2016-07-15

Neuroimaging holds the promise that it may one day aid the clinical assessment. However, the vast majority of studies using resting-state functional magnetic resonance imaging (fMRI) have reported average differences between Parkinson's disease (PD) patients and healthy controls, which do not permit inferences at the level of individuals. This study was to develop a model for the prediction of PD illness severity ratings from individual fMRI brain scan. The resting-state fMRI scans were obtained from 84 patients with PD and the Unified Parkinson's Disease Rating Scale-III (UPDRS-III) scores were obtained before scanning. The RVR method was used to predict clinical scores (UPDRS-III) from fMRI scans. The application of RVR to whole-brain resting-state fMRI data allowed prediction of UPDRS-III scores with statistically significant accuracy (correlation=0.35, P-value=0.001; mean sum of squares=222.17, P-value=0.002). This prediction was informed strongly by negative weight areas including prefrontal lobe and medial occipital lobe, and positive weight areas including medial parietal lobe. It was suggested that fMRI scans contained sufficient information about neurobiological change in patients with PD to permit accurate prediction about illness severity, on an individual subject basis. Our results provided preliminary evidence, as proof-of-concept, to support that fMRI might be possible to be a clinically useful quantitative assessment aid in PD at individual level. This may enable clinicians to target those uncooperative patients and machines to replace human for a more efficient use of health care resources. Copyright © 2016 Elsevier B.V. All rights reserved.

Implant detectibility of intervertebral disc spacers in post fusion MRI: evaluation of the MRI scan quality by using a scoring system--an in vitro study.

PubMed

Ernstberger, Thorsten; Heidrich, Gabert; Schultz, Wolfgang; Grabbe, Eckhardt

2007-02-01

Intervertebral spacers for anterior spine fusion are made of different materials, such as titanium and cobalt chromium alloys and carbon fiber-reinforced polymers. Implant-related susceptibility artifacts can decrease the quality of MRI scans. The aim of this cadaveric study was to demonstrate the extent that implant-related MRI artifacting affects the postfusion differentiation of determined regions of interest (ROIs). In six cadaveric porcine spines, we evaluated the postimplantation MRI scans of a titanium, cobalt-chromium and carbon spacer that differed in shape and surface qualities. A spacer made of human cortical bone was used as a control. A defined evaluation unit was divided into ROIs to characterize the spinal canal as well as the intervertebral disc space. Considering 15 different MRI sequences read independently by an interobserver-validated team of specialists the artifact-affected image quality of the median MRI slice was rated on a score of 0-3. A maximum score of 18 points (100%) for the determined ROIs was possible. Turbo spin echo sequences produced the best scores for all spacers and the control. Only the control achieved a score of 100%. For the determined ROI maximum scores for the cobalt-chromium, titanium and carbon spacers were 24%, 32% and 84%, respectively. By using favored T1 TSE sequences the carbon spacer showed a clear advantage in postfusion spinal imaging. Independent of artifact dimensions, the scoring system used allowed us to create an implant-related ranking of MRI scan quality in reference to the bone control.

DOE Office of Scientific and Technical Information (OSTI.GOV)

James, J; Place, V; Panda, A

Purpose: Several institutions have developed MRI guidelines for patients with MR-unsafe or MR-conditional pacemakers. Here we highlight the role of a medical physicist in implementing these guidelines for non-pacemaker dependent patients. Guidelines: Implementing these guidelines requires involvement from several medical specialties and a strong collaboration with the site MRI supervisor to develop a structured workflow. A medical physicist is required to be present during the scan to supervise the MR scanning and to maintain a safety checklist that ensures: 1) uninterrupted patient communication with the technologist, 2) continuous patient physiologic monitoring (e.g. blood pressure and electrocardiography) by a trained nurse,more » 3) redundant patient vitals monitoring (e.g. pulse oximetry) due to the possibility of in vivo electrocardiography reading fluctuations during image acquisition. A radiologist is strongly recommended to be available to review the images before patients are discharged from the scanner. Pacemaker MRI should be restricted to 1.5T field strength. The MRI sequences should be optimized by the physicist with regards to: a) SAR: limited to <1.5 W/Kg for MR-unsafe pacemakers in normal operating mode, b) RF exposure time: <30 min, c) Coils: use T/R coils but not restricted to such, d) Artifacts: further optimization of sequences whenever image quality is compromised due to the pacemaker. In particular, cardiac, breast and left-shoulder MRIs are most susceptible to these artifacts. Possible strategies to lower the SAR include: a) BW reduction, 2) echo-train-length reduction, 3) increase TR, 4) decrease number of averages, 5) decrease flip angle, 6) reduce slices and/or a combination of all the options. Conclusion: A medical physicist in collaboration with the MR supervisor plays an important role in the supervision/implementation of safe MR scanning of pacemaker patients. Developing and establishing a workflow has enabled our institution to scan over 30 patients with pacemakers without complications, including 3 cardiac MR exams.« less

Magnetic resonance imaging evaluation of intervertebral test spacers: an experimental comparison of magnesium versus titanium and carbon fiber reinforced polymers as biomaterials.

PubMed

Ernstberger, T; Buchhorn, G; Heidrich, G

2010-03-01

Intervertebral spacers are made of different materials, which can affect the postfusion magnetic resonance imaging (MRI) scans. Susceptibility artifacts, especially for metallic implants, can decrease the image quality. This study aimed to determine whether magnesium as a lightweight and biocompatible metal is suitable as a biomaterial for spinal implants based on its MRI artifacting behavior. To compare artifacting behaviors, we implanted into one porcine cadaveric spine different test spacers made of magnesium, titanium, and CFRP. All test spacers were scanned using two T1-TSE MRI sequences. The artifact dimensions were traced on all scans and statistically analyzed. The total artifact volume and median artifact area of the titanium spacers were statistically significantly larger than magnesium spacers (P < 0.001), while magnesium and CFRP spacers produced almost identical artifacting behaviors (P > 0.05). Our results suggest that spinal implants made with magnesium alloys will behave more like CFRP devices in MRI scans.

Correlation of the CT Compatible Stereotaxic Craniotomy with MRI Scans of the Patients for Removing Cranial Lesions Located Eloquent Areas and Deep Sites of Brain.

PubMed

Gulsen, Salih

2015-03-15

The first goal in neurosurgery is to protect neural function as long as it is possible. Moreover, while protecting the neural function, a neurosurgeon should extract the maximum amount of tumoral tissue from the tumour region of the brain. So neurosurgery and technological advancement go hand in hand to realize this goal. Using of CT compatible stereotaxy for removing a cranial tumour is to be commended as a cornerstone of these technological advancements. Following CT compatible stereotaxic system applications in neurosurgery, different techniques have taken place in neurosurgical practice. These techniques are magnetic resonance imaging (MRI), MRI compatible stereotaxis, frameless stereotaxy, volumetric stereotaxy, functional MRI, diffusion tensor (DT) imaging techniques (tractography of the white matter), intraoperative MRI and neuronavigation systems. However, to use all of this equipment having these technologies would be impossible because of economic reasons. However, when we correlated this technique with MRI scans of the patients with CT compatible stereotaxy scans, it is possible to provide gross total resection and protect and improve patients' neural functions.

Super-resolution reconstruction in frequency, image, and wavelet domains to reduce through-plane partial voluming in MRI.

PubMed

Gholipour, Ali; Afacan, Onur; Aganj, Iman; Scherrer, Benoit; Prabhu, Sanjay P; Sahin, Mustafa; Warfield, Simon K

2015-12-01

To compare and evaluate the use of super-resolution reconstruction (SRR), in frequency, image, and wavelet domains, to reduce through-plane partial voluming effects in magnetic resonance imaging. The reconstruction of an isotropic high-resolution image from multiple thick-slice scans has been investigated through techniques in frequency, image, and wavelet domains. Experiments were carried out with thick-slice T2-weighted fast spin echo sequence on the Academic College of Radiology MRI phantom, where the reconstructed images were compared to a reference high-resolution scan using peak signal-to-noise ratio (PSNR), structural similarity image metric (SSIM), mutual information (MI), and the mean absolute error (MAE) of image intensity profiles. The application of super-resolution reconstruction was then examined in retrospective processing of clinical neuroimages of ten pediatric patients with tuberous sclerosis complex (TSC) to reduce through-plane partial voluming for improved 3D delineation and visualization of thin radial bands of white matter abnormalities. Quantitative evaluation results show improvements in all evaluation metrics through super-resolution reconstruction in the frequency, image, and wavelet domains, with the highest values obtained from SRR in the image domain. The metric values for image-domain SRR versus the original axial, coronal, and sagittal images were PSNR = 32.26 vs 32.22, 32.16, 30.65; SSIM = 0.931 vs 0.922, 0.924, 0.918; MI = 0.871 vs 0.842, 0.844, 0.831; and MAE = 5.38 vs 7.34, 7.06, 6.19. All similarity metrics showed high correlations with expert ranking of image resolution with MI showing the highest correlation at 0.943. Qualitative assessment of the neuroimages of ten TSC patients through in-plane and out-of-plane visualization of structures showed the extent of partial voluming effect in a real clinical scenario and its reduction using SRR. Blinded expert evaluation of image resolution in resampled out-of-plane views consistently showed the superiority of SRR compared to original axial and coronal image acquisitions. Thick-slice 2D T2-weighted MRI scans are part of many routine clinical protocols due to their high signal-to-noise ratio, but are often severely affected by through-plane partial voluming effects. This study shows that while radiologic assessment is performed in 2D on thick-slice scans, super-resolution MRI reconstruction techniques can be used to fuse those scans to generate a high-resolution image with reduced partial voluming for improved postacquisition processing. Qualitative and quantitative evaluation showed the efficacy of all SRR techniques with the best results obtained from SRR in the image domain. The limitations of SRR techniques are uncertainties in modeling the slice profile, density compensation, quantization in resampling, and uncompensated motion between scans.

Prospective multi-centre Voxel Based Morphometry study employing scanner specific segmentations: Procedure development using CaliBrain structural MRI data

PubMed Central

2009-01-01

Background Structural Magnetic Resonance Imaging (sMRI) of the brain is employed in the assessment of a wide range of neuropsychiatric disorders. In order to improve statistical power in such studies it is desirable to pool scanning resources from multiple centres. The CaliBrain project was designed to provide for an assessment of scanner differences at three centres in Scotland, and to assess the practicality of pooling scans from multiple-centres. Methods We scanned healthy subjects twice on each of the 3 scanners in the CaliBrain project with T1-weighted sequences. The tissue classifier supplied within the Statistical Parametric Mapping (SPM5) application was used to map the grey and white tissue for each scan. We were thus able to assess within scanner variability and between scanner differences. We have sought to correct for between scanner differences by adjusting the probability mappings of tissue occupancy (tissue priors) used in SPM5 for tissue classification. The adjustment procedure resulted in separate sets of tissue priors being developed for each scanner and we refer to these as scanner specific priors. Results Voxel Based Morphometry (VBM) analyses and metric tests indicated that the use of scanner specific priors reduced tissue classification differences between scanners. However, the metric results also demonstrated that the between scanner differences were not reduced to the level of within scanner variability, the ideal for scanner harmonisation. Conclusion Our results indicate the development of scanner specific priors for SPM can assist in pooling of scan resources from different research centres. This can facilitate improvements in the statistical power of quantitative brain imaging studies. PMID:19445668

High-resolution whole-brain DCE-MRI using constrained reconstruction: Prospective clinical evaluation in brain tumor patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Yi, E-mail: yiguo@usc.edu; Zhu, Yinghua; Lingala, Sajan Goud

Purpose: To clinically evaluate a highly accelerated T1-weighted dynamic contrast-enhanced (DCE) MRI technique that provides high spatial resolution and whole-brain coverage via undersampling and constrained reconstruction with multiple sparsity constraints. Methods: Conventional (rate-2 SENSE) and experimental DCE-MRI (rate-30) scans were performed 20 minutes apart in 15 brain tumor patients. The conventional clinical DCE-MRI had voxel dimensions 0.9 × 1.3 × 7.0 mm{sup 3}, FOV 22 × 22 × 4.2 cm{sup 3}, and the experimental DCE-MRI had voxel dimensions 0.9 × 0.9 × 1.9 mm{sup 3}, and broader coverage 22 × 22 × 19 cm{sup 3}. Temporal resolution was 5 smore » for both protocols. Time-resolved images and blood–brain barrier permeability maps were qualitatively evaluated by two radiologists. Results: The experimental DCE-MRI scans showed no loss of qualitative information in any of the cases, while achieving substantially higher spatial resolution and whole-brain spatial coverage. Average qualitative scores (from 0 to 3) were 2.1 for the experimental scans and 1.1 for the conventional clinical scans. Conclusions: The proposed DCE-MRI approach provides clinically superior image quality with higher spatial resolution and coverage than currently available approaches. These advantages may allow comprehensive permeability mapping in the brain, which is especially valuable in the setting of large lesions or multiple lesions spread throughout the brain.« less

Gray Matter and Intelligence Factors: Is There a Neuro-g?

ERIC Educational Resources Information Center

Haier, Richard J.; Colom, Roberto; Schroeder, David H.; Condon, Christopher A.; Tang, Cheuk; Eaves, Emily; Head, Kevin

2009-01-01

Heterogeneous results among neuro-imaging studies using psychometric intelligence measures may result from the variety of tests used. The g-factor may provide a common metric across studies. Here we derived a g-factor from a battery of eight cognitive tests completed by 6929 young adults, 40 of whom also completed structural MRI scans. Regional…

Improvement in cerebral function with treatment of posttraumatic stress disorder.

PubMed

Roy, Michael J; Francis, Jennifer; Friedlander, Joshua; Banks-Williams, Lisa; Lande, Raymond G; Taylor, Patricia; Blair, James; McLellan, Jennifer; Law, Wendy; Tarpley, Vanita; Patt, Ivy; Yu, Henry; Mallinger, Alan; Difede, Joann; Rizzo, Albert; Rothbaum, Barbara

2010-10-01

Posttraumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) are signature illnesses of the Iraq and Afghanistan wars, but current diagnostic and therapeutic measures for these conditions are suboptimal. In our study, functional magnetic resonance imaging (fMRI) is used to try to differentiate military service members with: PTSD and mTBI, PTSD alone, mTBI alone, and neither PTSD nor mTBI. Those with PTSD are then randomized to virtual reality exposure therapy or imaginal exposure. fMRI is repeated after treatment and along with the Clinician-Administered PTSD Scale (CAPS) and Clinical Global Impression (CGI) scores to compare with baseline. Twenty subjects have completed baseline fMRI scans, including four controls and one mTBI only; of 15 treated for PTSD, eight completed posttreatment scans. Most subjects have been male (93%) and Caucasian (83%), with a mean age of 34. Significant improvements are evident on fMRI scans, and corroborated by CGI scores, but CAPS scores improvements are modest. In conclusion, CGI scores and fMRI scans indicate significant improvement in PTSD in both treatment arms, though CAPS score improvements are less robust. © 2010 Association for Research in Nervous and Mental Disease.

Clinical Application of Standardized Cognitive Assessment Using fMRI. I. Matrix Reasoning

PubMed Central

Allen, Mark D.; Fong, Alina K.

2008-01-01

Functional MRI is increasingly recognized for its potential as a powerful new tool in clinical neuropsychology. This is likely due to the fact that, with some degree of innovation, it is possible to convert practically any familiar cognitive test into one that can be performed in the MRI scanning environment. However, like any assessment approach, meaningful interpretation of fMRI data for the purpose of patient evaluation crucially requires normative data derived from a sample of unimpaired persons, against which individual patients may be compared. Currently, no such normative data are available for any fMRI-based cognitive testing protocol. In this paper, we report the first of a series of fMRI-compatible cognitive assessment protocols, a matrix reasoning test (f-MRT), for which normative samples of functional activation have been collected from unimpaired control subjects and structured in a manner that makes individual patient evaluation possible in terms of familiar z-score distributions. Practical application of the f-MRT is demonstrated via a contrastive case-study of two individuals with cognitive impairment in which fMRI data identifies subtleties in patient deficits otherwise missed by conventional measures of performance. PMID:19641250

Association between MRI structural features and cognitive measures in pediatric multiple sclerosis

NASA Astrophysics Data System (ADS)

Amoroso, N.; Bellotti, R.; Fanizzi, A.; Lombardi, A.; Monaco, A.; Liguori, M.; Margari, L.; Simone, M.; Viterbo, R. G.; Tangaro, S.

2017-09-01

Multiple sclerosis (MS) is an inflammatory and demyelinating disease associated with neurodegenerative processes that lead to brain structural changes. The disease affects mostly young adults, but 3-5% of cases has a pediatric onset (POMS). Magnetic Resonance Imaging (MRI) is generally used for diagnosis and follow-up in MS patients, however the most common MRI measures (e.g. new or enlarging T2-weighted lesions, T1-weighted gadolinium- enhancing lesions) have often failed as surrogate markers of MS disability and progression. MS is clinically heterogenous with symptoms that can include both physical changes (such as visual loss or walking difficulties) and cognitive impairment. 30-50% of POMS experience prominent cognitive dysfunction. In order to investigate the association between cognitive measures and brain morphometry, in this work we present a fully automated pipeline for processing and analyzing MRI brain scans. Relevant anatomical structures are segmented with FreeSurfer; besides, statistical features are computed. Thus, we describe the data referred to 12 patients with early POMS (mean age at MRI: 15.5 +/- 2.7 years) with a set of 181 structural features. The major cognitive abilities measured are verbal and visuo-spatial learning, expressive language and complex attention. Data was collected at the Department of Basic Sciences, Neurosciences and Sense Organs, University of Bari, and exploring different abilities like the verbal and visuo-spatial learning, expressive language and complex attention. Different regression models and parameter configurations are explored to assess the robustness of the results, in particular Generalized Linear Models, Bayes Regression, Random Forests, Support Vector Regression and Artificial Neural Networks are discussed.

The insula is not specifically involved in disgust processing: an fMRI study.

PubMed

Schienle, A; Stark, R; Walter, B; Blecker, C; Ott, U; Kirsch, P; Sammer, G; Vaitl, D

2002-11-15

fMRI studies have shown that the perception of facial disgust expressions specifically activates the insula. The present fMRI study investigated whether this structure is also involved in the processing of visual stimuli depicting non-mimic disgust elicitors compared to fear-inducing and neutral scenes. Twelve female subjects were scanned while viewing alternating blocks of 40 disgust-inducing, 40 fear-inducing and 40 affectively neutral pictures, shown for 1.5 s each. Afterwards, affective ratings were assessed. The disgust pictures, rated as highly repulsive, induced activation in the insula, the amygdala, the orbitofrontal and occipito-temporal cortex. Since during the fear condition the insula was also involved, our findings do not fit the idea of the insula as a specific disgust processor.

Recent progress and outstanding issues in motion correction in resting state fMRI

PubMed Central

Power, Jonathan D; Schlaggar, Bradley L; Petersen, Steven E

2014-01-01

The purpose of this review is to communicate and synthesize recent findings related to motion artifact in resting state fMRI. In 2011, three groups reported that small head movements produced spurious but structured noise in brain scans, causing distance-dependent changes in signal correlations. This finding has prompted both methods development and the re-examination of prior findings with more stringent motion correction. Since 2011, over a dozen papers have been published specifically on motion artifact in resting state fMRI. We will attempt to distill these papers to their most essential content. We will point out some aspects of motion artifact that are easily or often overlooked. Throughout the review, we will highlight gaps in current knowledge and avenues for future research. PMID:25462692

[Joint correction for motion artifacts and off-resonance artifacts in multi-shot diffusion magnetic resonance imaging].

PubMed

Wu, Wenchuan; Fang, Sheng; Guo, Hua

2014-06-01

Aiming at motion artifacts and off-resonance artifacts in multi-shot diffusion magnetic resonance imaging (MRI), we proposed a joint correction method in this paper to correct the two kinds of artifacts simultaneously without additional acquisition of navigation data and field map. We utilized the proposed method using multi-shot variable density spiral sequence to acquire MRI data and used auto-focusing technique for image deblurring. We also used direct method or iterative method to correct motion induced phase errors in the process of deblurring. In vivo MRI experiments demonstrated that the proposed method could effectively suppress motion artifacts and off-resonance artifacts and achieve images with fine structures. In addition, the scan time was not increased in applying the proposed method.

Functional connectivity density mapping: comparing multiband and conventional EPI protocols.

PubMed

Cohen, Alexander D; Tomasi, Dardo; Shokri-Kojori, Ehsan; Nencka, Andrew S; Wang, Yang

2018-06-01

Functional connectivity density mapping (FCDM) is a newly developed data-driven technique that quantifies the number of local and global functional connections for each voxel in the brain. In this study, we evaluated reproducibility, sensitivity, and specificity of both local functional connectivity density (lFCD) and global functional connectivity density (gFCD). We compared these metrics using the human connectome project (HCP) compatible high-resolution (2 mm isotropic, TR = 0.8 s) multiband (MB), and more typical, lower resolution (3.5 mm isotropic, TR = 2.0 s) single-band (SB) resting state functional MRI (rs-fMRI) acquisitions. Furthermore, in order to be more clinically feasible, only rs-fMRI scans that lasted seven minutes were tested. Subjects were scanned twice within a two-week span. We found sensitivity and specificity increased and reproducibility either increased or did not change for the MB compared to the SB acquisitions. The MB scans also showed improved gray matter/white matter contrast compared to the SB scans. The lFCD and gFCD patterns were similar across MB and SB scans and confined predominantly to gray matter. We also observed a strong spatial correlation of FCD between MB and SB scans indicating the two acquisitions provide similar information. These findings indicate high-resolution MB acquisitions improve the quality of FCD data, and seven minute rs-fMRI scan can provide robust FCD measurements.

Safety evaluation of a leadless transcatheter pacemaker for magnetic resonance imaging use.

PubMed

Soejima, Kyoko; Edmonson, Jonathan; Ellingson, Michael L; Herberg, Ben; Wiklund, Craig; Zhao, Jing

2016-10-01

Increased magnetic resonance imaging (MRI) adoption and demand are driving the need for device patients to have safe access to MRI. The aim of this study was to address the interactions of MRI with the Micra transcatheter pacemaker system. A strategy was developed to evaluate potential MRI risks including device heating, unintended cardiac stimulation, force, torque, vibration, and device malfunction. Assessment of MRI-induced device heating was conducted using a phantom containing gelled saline, and Monte Carlo simulations incorporating these results were conducted to simulate numerous combinations of human body models, position locations in the MRI scanner bore, and a variety of coil designs. Lastly, a patient with a Micra pacemaker who underwent a clinically indicated MRI scan is presented. Compared to traditional MRI conditional pacemakers, the overall risk with Micra was greatly reduced because of the small size of the device and the absence of a lead. The modeling results predicted that the nonperfused temperature rise of the device would be less than 0.4°C at 1.5 T and 0.5°C at 3 T and that the risk of device heating with multiple device implants was not increased as compared with a single device. The clinical case study revealed no MRI-related complications. The MRI safety assessment tests conducted for the Micra pacemaker demonstrate that patients with a single device or multiple devices can safely undergo MRI scans in both 1.5- and 3-T MRI scanners. No MRI-related complications were observed in a patient implanted with a Micra pacemaker undergoing a clinically indicated scan. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Phase 0 Trial of Itraconazole for Early-Stage Non-Small Cell Lung Cancer

DTIC Science & Technology

2016-10-01

tissue and blood sampling in addition to magnetic resonance imaging ( MRI ) scans for biomarker analysis. At the time of surgery, resected tissue will...original proposal, these subjects underwent study-related MRI scans, skin biopsies, blood tests, treatment with itraconazole, and surgical resection...not complete serial MRIs scans. Task 2: Determine anti-angiogenic effects of itraconazole Subtask 2a: Blood-based PD studies As described in the

Fetal brain volumetry through MRI volumetric reconstruction and segmentation

PubMed Central

Estroff, Judy A.; Barnewolt, Carol E.; Connolly, Susan A.; Warfield, Simon K.

2013-01-01

Purpose Fetal MRI volumetry is a useful technique but it is limited by a dependency upon motion-free scans, tedious manual segmentation, and spatial inaccuracy due to thick-slice scans. An image processing pipeline that addresses these limitations was developed and tested. Materials and methods The principal sequences acquired in fetal MRI clinical practice are multiple orthogonal single-shot fast spin echo scans. State-of-the-art image processing techniques were used for inter-slice motion correction and super-resolution reconstruction of high-resolution volumetric images from these scans. The reconstructed volume images were processed with intensity non-uniformity correction and the fetal brain extracted by using supervised automated segmentation. Results Reconstruction, segmentation and volumetry of the fetal brains for a cohort of twenty-five clinically acquired fetal MRI scans was done. Performance metrics for volume reconstruction, segmentation and volumetry were determined by comparing to manual tracings in five randomly chosen cases. Finally, analysis of the fetal brain and parenchymal volumes was performed based on the gestational age of the fetuses. Conclusion The image processing pipeline developed in this study enables volume rendering and accurate fetal brain volumetry by addressing the limitations of current volumetry techniques, which include dependency on motion-free scans, manual segmentation, and inaccurate thick-slice interpolation. PMID:20625848

Comparison of qualitative and quantitative analysis of T2-weighted MRI scans in chronic-progressive multiple sclerosis

NASA Astrophysics Data System (ADS)

Adams, Hans-Peter; Wagner, Simone; Koziol, James A.

1998-06-01

Magnetic resonance imaging (MRI) is routinely used for the diagnosis of multiple sclerosis (MS), and for objective assessment of the extent of disease as a marker of treatment efficacy in MS clinical trials. The purpose of this study is to compare the evaluation of T2-weighted MRI scans in MS patients using a semi-automated quantitative technique with an independent assessment by a neurologist. Baseline, 6- month, and 12-month T2-weighted MRI scans from 41 chronic progressive MS patients were examined. The lesion volume ranged from 0.50 to 51.56 cm2 (mean: 8.08 cm2). Reproducibility of the quantitative technique was assessed by the re-evaluation of a random subset of 20 scans, the coefficient of variation of the replicate determinations was 8.2%. The reproducibility of the neurologist evaluations was assessed by the re-evaluation of a random subset of 10 patients. The rank correlation between the results of the two methods was 0.097, which did not significantly differ from zero. Disease-related activity in T2-weighted MRI scans is a multi-dimensional construct, and is not adequately summarized solely by determination of lesion volume. In this setting, image analysis software should not only support storage and retrieval as sets of pixels, but should also support links to an anatomical dictionary.

Establishing the resting state default mode network derived from functional magnetic resonance imaging tasks as an endophenotype: A twins study.

PubMed

Korgaonkar, Mayuresh S; Ram, Kaushik; Williams, Leanne M; Gatt, Justine M; Grieve, Stuart M

2014-08-01

The resting state default mode network (DMN) has been shown to characterize a number of neurological and psychiatric disorders. Evidence suggests an underlying genetic basis for this network and hence could serve as potential endophenotype for these disorders. Heritability is a defining criterion for endophenotypes. The DMN is measured either using a resting-state functional magnetic resonance imaging (fMRI) scan or by extracting resting state activity from task-based fMRI. The current study is the first to evaluate heritability of this task-derived resting activity. 250 healthy adult twins (79 monozygotic and 46 dizygotic same sex twin pairs) completed five cognitive and emotion processing fMRI tasks. Resting state DMN functional connectivity was derived from these five fMRI tasks. We validated this approach by comparing connectivity estimates from task-derived resting activity for all five fMRI tasks, with those obtained using a dedicated task-free resting state scan in an independent cohort of 27 healthy individuals. Structural equation modeling using the classic twin design was used to estimate the genetic and environmental contributions to variance for the resting-state DMN functional connectivity. About 9-41% of the variance in functional connectivity between the DMN nodes was attributed to genetic contribution with the greatest heritability found for functional connectivity between the posterior cingulate and right inferior parietal nodes (P<0.001). Our data provide new evidence that functional connectivity measures from the intrinsic DMN derived from task-based fMRI datasets are under genetic control and have the potential to serve as endophenotypes for genetically predisposed psychiatric and neurological disorders. Copyright © 2014 Wiley Periodicals, Inc.

Leg MRI scan

MedlinePlus

... anything that contains metal into the scanner room. Considerations Tests that may be done instead of an ... Magnetic resonance imaging - ankle; MRI - femur; MRI - leg Patient Instructions Femur fracture repair - discharge Hip fracture - discharge ...

Are there differences in brain morphometry between twins and unrelated singletons? A pediatric MRI study.

PubMed

Ordaz, S J; Lenroot, R K; Wallace, G L; Clasen, L S; Blumenthal, J D; Schmitt, J E; Giedd, J N

2010-04-01

Twins provide a unique capacity to explore relative genetic and environmental contributions to brain development, but results are applicable to non-twin populations only to the extent that twin and singleton brains are alike. A reason to suspect differences is that as a group twins are more likely than singletons to experience adverse prenatal and perinatal events that may affect brain development. We sought to assess whether this increased risk leads to differences in child or adolescent brain anatomy in twins who do not experience behavioral or neurological sequelae during the perinatal period. Brain MRI scans of 185 healthy pediatric twins (mean age = 11.0, SD = 3.6) were compared to scans of 167 age- and sex-matched unrelated singletons on brain structures measured, which included gray and white matter lobar volumes, ventricular volume, and area of the corpus callosum. There were no significant differences between groups for any structure, despite sufficient power for low type II (i.e. false negative) error. The implications of these results are twofold: (1) within this age range and for these measures, it is appropriate to include healthy twins in studies of typical brain development, and (2) findings regarding heritability of brain structures obtained from twin studies can be generalized to non-twin populations.

Putaminal volume and diffusion in early familial Creutzfeldt-Jakob disease.

PubMed

Seror, Ilana; Lee, Hedok; Cohen, Oren S; Hoffmann, Chen; Prohovnik, Isak

2010-01-15

The putamen is centrally implicated in the pathophysiology of Creutzfeldt-Jakob Disease (CJD). To our knowledge, its volume has never been measured in this disease. We investigated whether gross putaminal atrophy can be detected by MRI in early stages, when the diffusion is already reduced. Twelve familial CJD patients with the E200K mutation and 22 healthy controls underwent structural and diffusion MRI scans. The putamen was identified in anatomical scans by two methods: manual tracing by a blinded investigator, and automatic parcellation by a computerized segmentation procedure (FSL FIRST). For each method, volume and mean Apparent Diffusion Coefficient (ADC) were calculated. ADC was significantly lower in CJD patients (697+/-64 microm(2)/s vs. 750+/-31 microm(2)/s, p<0.005), as expected, but the volume was not reduced. The computerized FIRST delineation yielded comparable ADC values to the manual method, but computerized volumes were smaller than manual tracing values. We conclude that significant diffusion reduction in the putamen can be detected by delineating the structure manually or with a computerized algorithm. Our findings confirm and extend previous voxel-based and observational studies. Putaminal volume was not reduced in our early-stage patients, thus confirming that diffusion abnormalities precede detectible atrophy in this structure.

Saethre-Chotzen syndrome, Pro136His TWIST mutation, hearing loss, and external and middle ear structural anomalies: report on a Brazilian family.

PubMed

Lamônica, Dionísia A C; Maximino, Luciana P; Feniman, Mariza Ribeiro; Silva, Greyce K; Zanchetta, Sthella; Abramides, Dagma V M; Passos-Bueno, Maria Rita; Rocha, Kátia; Richieri-Costa, Antonio

2010-09-01

To describe the clinical, speech, hearing, and imaging findings in three members of a Brazilian family with Saethre-Chotzen syndrome (SCS) who presented some unusual characteristics within the spectrum of the syndrome. Clinical evaluation was performed by a multidisciplinary team. Direct sequencing of the polymerase chain reaction-amplified coding region of the TWIST1 gene, routine and electrophysiological hearing evaluation, speech evaluation, and imaging studies through computed tomography (CT) scan and magnetic resonance imaging (MRI) were performed. TWIST1 gene analysis revealed a Pro136His mutation in all patients. Hearing evaluation showed peripherial and mixed hearing loss in two of the patients, one of them with severe unilateral microtia. Computed tomography scan showed structural middle ear anomalies, and MRI showed distortion of the skull contour as well as some of the brain structures. We report a previously undescribed TWIST1 gene mutation in patients with SCS. There is evidence that indicates hearing loss (conductive and mixed) can be related both with middle ear (microtia, high jugular bulb, and enlarged vestibules) as well as with brain stem anomalies. Here we discuss the relationship between the gene mutation and the clinical, imaging, speech, and hearing findings.

Metal artefacts severely hamper magnetic resonance imaging of the rotator cuff tendons after rotator cuff repair with titanium suture anchors.

PubMed

Schröder, Femke F; Huis In't Veld, Rianne; den Otter, Lydia A; van Raak, Sjoerd M; Ten Haken, Bennie; Vochteloo, Anne J H

2018-04-01

The rate of retear after rotator cuff surgery is 17%. Magnetic resonance imaging (MRI) scans are used for confirmative diagnosis of retear. However, because of the presence of titanium suture anchors, metal artefacts on the MRI are common. The present study evaluated the diagnostic value of MRI after rotator cuff tendon surgery with respect to assessing the integrity as well as the degeneration and atrophy of the rotator cuff tendons when titanium anchors are in place. Twenty patients who underwent revision surgery of the rotator cuff as a result of a clinically suspected retear between 2013 and 2015 were included. The MRI scans of these patients were retrospectively analyzed by four specialized shoulder surgeons and compared with intra-operative findings (gold standard). Sensitivity and interobserver agreement among the surgeons in assessing retears as well as the Goutallier and Warner classification were examined. In 36% (range 15% to 50%) of the pre-operative MRI scans, the observers could not review the rotator cuff tendons. When the rotator cuff tendons were assessable, a diagnostic accuracy with a mean sensitivity of 0.84 (0.70 to 1.0) across the surgeons was found, with poor interobserver agreement (kappa = 0.12). Metal artefacts prevented accurate diagnosis from MRI scans of rotator cuff retear in 36% of the patients studied.

SU-C-17A-02: Sirius MRI Markers for Prostate Post-Implant Assessment: MR Protocol Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, T; Wang, J; Kudchadker, R

Purpose: Currently, CT is used to visualize prostate brachytherapy sources, at the expense of accurate structure contouring. MRI is superior to CT for anatomical delineation, but the sources appear as voids on MRI images. Previously we have developed Sirius MRI markers (C4 Imaging) to replace spacers to assist source localization on MRI images. Here we develop an MRI pulse sequence protocol that enhances the signal of these markers to enable MRI-only post-implant prostate dosimetric analysis. Methods: To simulate a clinical scenario, a CIRS multi-modality prostate phantom was implanted with 66 markers and 86 sources. The implanted phantom was imaged onmore » both 1.5T and 3.0T GE scanners under various conditions, different pulse sequences (2D fast spin echo [FSE], 3D balanced steadystate free precession [bSSFP] and 3D fast spoiled gradient echo [FSPGR]), as well as varying amount of padding to simulate various patient sizes and associated signal fall-off from the surface coil elements. Standard FSE sequences from the current clinical protocols were also evaluated. Marker visibility, marker size, intra-marker distance, total scan time and artifacts were evaluated for various combinations of echo time, repetition time, flip angle, number of excitations, bandwidth, slice thickness and spacing, fieldof- view, frequency/phase encoding steps and frequency direction. Results: We have developed a 3D FSPGR pulse sequence that enhances marker signal and ensures the integrity of the marker shape while maintaining reasonable scan time. For patients contraindicated for 3.0T, we have also developed a similar sequence for 1.5T scanners. Signal fall-off with distance from prostate to coil can be compensated mainly by decreasing bandwidth. The markers are not visible using standard FSE sequences. FSPGR sequences are more robust for consistent marker visualization as compared to bSSFP sequences. Conclusion: The developed MRI pulse sequence protocol for Sirius MRI markers assists source localization to enable MRIonly post-implant prostate dosimetric analysis. S.J. Frank is a co-founder of C4 Imaging (manufactures the MRI markers)« less

An Observational Study to Assess Brain MRI Change and Disease Progression in Multiple Sclerosis Clinical Practice-The MS-MRIUS Study.

PubMed

Zivadinov, Robert; Khan, Nasreen; Medin, Jennie; Christoffersen, Pia; Price, Jennifer; Korn, Jonathan R; Bonzani, Ian; Dwyer, Michael G; Bergsland, Niels; Carl, Ellen; Silva, Diego; Weinstock-Guttman, Bianca

2017-05-01

To describe methodology, interim baseline, and longitudinal magnetic resonance imaging (MRI) acquisition parameter characteristics of the multiple sclerosis clinical outcome and MRI in the United States (MS-MRIUS). The MS-MRIUS is an ongoing longitudinal and retrospective study of MS patients on fingolimod. Clinical and brain MRI image scan data were collected from 600 patients across 33 MS centers in the United States. MRI brain outcomes included change in whole-brain volume, lateral ventricle volume, T2- and T1-lesion volumes, and new/enlarging T2 and gadolinium-enhancing lesions. Interim baseline and longitudinal MRI acquisition parameters results are presented for 252 patients. Mean age was 44 years and 81% were female. Forty percent of scans had 3-dimensional (3D) T1 sequence in the preindex period, increasing to 50% in the postindex period. Use of 2-dimensional (2D) T1 sequence decreased over time from 85% in the preindex period to 65% in the postindex. About 95% of the scans with FLAIR and 2D T1-WI were considered acceptable or good quality compared to 99-100% with 3D T1-WI. There were notable changes in MRI hardware, software, and coil (39.5% in preindex to index and 50% in index to postindex). MRI sequence parameters (orientation, thickness, or protocol) differed for 36%, 29%, and 20% of index/postindex scans for FLAIR, 2D T1-WI, and 3D T1-WI, respectively. The MS-MRIUS study linked the clinical and brain MRI outcomes into an integrated database to create a cohort of fingolimod patients in real-world practice. Variability was observed in MRI acquisition protocols overtime. © 2016 The Authors. Journal of Neuroimaging published by Wiley Periodicals, Inc. on behalf of American Society of Neuroimaging.

Metamaterial Combining Electric- and Magnetic-Dipole-Based Configurations for Unique Dual-Band Signal Enhancement in Ultrahigh-Field Magnetic Resonance Imaging

PubMed Central

2017-01-01

Magnetic resonance imaging and spectroscopy (MRI and MRS) are both widely used techniques in medical diagnostics and research. One of the major thrusts in recent years has been the introduction of ultrahigh-field magnets in order to boost the sensitivity. Several MRI studies have examined further potential improvements in sensitivity using metamaterials, focusing on single frequency applications. However, metamaterials have yet to reach a level that is practical for routine MRI use. In this work, we explore a new metamaterial implementation for MRI, a dual-nuclei resonant structure, which can be used for both proton and heteronuclear magnetic resonance. Our approach combines two configurations, one based on a set of electric dipoles for the low frequency band, and the second based on a set of magnetic dipoles for the high frequency band. We focus on the implementation of a dual-nuclei metamaterial for phosphorus and proton imaging and spectroscopy at an ultrahigh-field strength of 7 T. In vivo scans using this flexible and compact structure show that it locally enhances both the phosphorus and proton transmit and receive sensitivities. PMID:28901137

Metamaterial Combining Electric- and Magnetic-Dipole-Based Configurations for Unique Dual-Band Signal Enhancement in Ultrahigh-Field Magnetic Resonance Imaging.

PubMed

Schmidt, Rita; Webb, Andrew

2017-10-11

Magnetic resonance imaging and spectroscopy (MRI and MRS) are both widely used techniques in medical diagnostics and research. One of the major thrusts in recent years has been the introduction of ultrahigh-field magnets in order to boost the sensitivity. Several MRI studies have examined further potential improvements in sensitivity using metamaterials, focusing on single frequency applications. However, metamaterials have yet to reach a level that is practical for routine MRI use. In this work, we explore a new metamaterial implementation for MRI, a dual-nuclei resonant structure, which can be used for both proton and heteronuclear magnetic resonance. Our approach combines two configurations, one based on a set of electric dipoles for the low frequency band, and the second based on a set of magnetic dipoles for the high frequency band. We focus on the implementation of a dual-nuclei metamaterial for phosphorus and proton imaging and spectroscopy at an ultrahigh-field strength of 7 T. In vivo scans using this flexible and compact structure show that it locally enhances both the phosphorus and proton transmit and receive sensitivities.

Assessment of gunshot bullet injuries with the use of magnetic resonance imaging.

PubMed

Hess, U; Harms, J; Schneider, A; Schleef, M; Ganter, C; Hannig, C

2000-10-01

Magnetic resonance imaging (MRI) is rarely used for preoperative assessment of shotgun injuries because of concerns of displacing the possibly ferromagnetic foreign body within the surrounding tissue. A total of 56 different projectiles underwent MRI testing for ferromagnetism and imaging quality in vitro and in pig carcasses with a commercially available 1.5-MRI scan. Image quality was compared with that of computed tomographic scans. Projectiles with ferromagnetic properties can be distinguished easily from nonferromagnetic ones by pretesting the motion of an identical projectile within the MRI coil. When ferromagnetic projectiles were excluded, MRI yielded the more precise images compared with other imaging techniques. Projectile localization and associated soft tissue injuries were visualized without artifacts in all cases. When ferromagnetic foreign bodies are excluded by pretesting their properties within the MRI with a comparative projectile, MRI portends an excellent imaging procedure for assessing the extent of injury and planning the removal by surgery.

[Dobutamine stress magnetic resonance imaging (DS-MRI), a valuable tool for the diagnosis of ischemic heart disease].

PubMed

van Dijkman, P R M; Kuijpers, Th J A; Blom, B M; van Herpen, G

2002-07-13

Assessment of the clinical applicability of DS-MRI for the detection of myocardial ischemia and myocardial viability. Prospective. In the period from 1 November 1999 to 31 October 2000, patients with suspected coronary artery disease who could not be studied by means of conventional bicycle ergometry underwent breath-hold DS-MRI (1 Tesla) 4 days after cessation of anti-ischemic medication. Three left ventricular short-axis planes were examined for the occurrence of disorders in wall movement during infusion of increasing doses of dobutamine (10, 20, 30 and 40 micrograms/kg/min). Temporary recovery of wall thickening in a previously diminished or non-contracting segment under 5 micrograms/kg/min of dobutamine was considered proof of viability. Development of hypo-, a- or dyskinesia at higher doses of dobutamine was taken to indicate ischemia. If the DS-MRI test was positive for ischemia, coronary angiography was performed. If indicated, this was followed by revascularisation. If DS-MRI did not reveal ischemia, the patient was seen at the outpatient department. Of the 100 patients (62 men and 38 women with an average age of 62 years, SD = 12) subjected to DS-MRI, 95 yielded results that were suitable for diagnosis. Of the 42 patients with DS-MRI scans that were considered positive for ischemia and in whom coronary angiography was subsequently performed, 41 had such coronary abnormalities that revascularisation was indicated. One patient was false-positive. All 53 patients with non-ischemic DS-MRI scans were followed-up for 11-23 months (mean 17 months). One patient died suddenly 2 weeks after the MRI-test. The other 52 patients did not experience any coronary events nor sudden cardiac death. The predictive value of a positive DS-MRI scan for ischemia was 98% and the predictive value of a negative DS-MRI scan was also 98%. DS-MRI is a safe diagnostic method for the detection or exclusion of myocardial ischemia and viability in patients with suspected coronary artery disease.

Neurological Imaging in Acquired Cranial Nerve Palsy: Ophthalmologists vs. Neurologists.

PubMed

Klein Hesselink, Tessa; Gutter, Mari; Polling, Jan Roelof

2017-09-01

Cranial nerve palsies often require neurological imaging by MRI. Guidelines on whether or not to utilize MRI have been absent or lack clarity. In daily practice, both neurologists and ophthalmologists treat patients with cranial nerve palsy and determine whether neuro-imaging is required. There appear to be differences in policy with respect to neuro-imaging. The question, which will be answered in this study, is the following: to what extent do differences in policy exist between ophthalmologists and neurologists regarding imaging by MRI of patients with acquired ocular cranial nerve palsy? PubMed database was searched for literature on acquired cranial nerve palsy and MRI scanning performed by ophthalmologists and neurologists. Case series published between 2000 and 2015 were included. The first author screened the literature on eligibility, profession of the authors, and conducted data abstraction. Ten case series were found eligible for analysis. A total of 889 cranial nerve palsies were described, 770 by ophthalmologists and 119 by neurologists. The age range of patients in all case series was 2 to 96 years of age. The oculomotor nerve was investigated in 162 patients, the trochlear nerve in 131 patients, and the abducens nerve in 486 patients. All neurologists (n=3) and 2 out of 7 investigated ophthalmologists recommended performing MRI scanning in every patient who presented with an ocular cranial nerve palsy, while 5 ophthalmologists (5/7) opted to triage patients for risk factors associated with cranial nerve palsies prior to ordering MRI imaging. When different groups of patients were viewed separately, it became apparent that almost all specialists agreed that every patient with a third nerve palsy and patients under 50 years of age should undergo MRI scanning. In patients with fourth nerve palsy, MRI scanning was not indicated. The neurologists in this study were more likely to perform MRI scanning in every patient presenting with ocular cranial nerve palsy. Ophthalmologists were more likely to determine risk factors associated with cranial nerve palsy, which they took into account when deciding whether or not to perform neurological imaging in patients aged more than 50 years or presenting with abducens nerve palsy.

A patch-based pseudo-CT approach for MRI-only radiotherapy in the pelvis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreasen, Daniel, E-mail: dana@dtu.dk

Purpose: In radiotherapy based only on magnetic resonance imaging (MRI), knowledge about tissue electron densities must be derived from the MRI. This can be achieved by converting the MRI scan to the so-called pseudo-computed tomography (pCT). An obstacle is that the voxel intensities in conventional MRI scans are not uniquely related to electron density. The authors previously demonstrated that a patch-based method could produce accurate pCTs of the brain using conventional T{sub 1}-weighted MRI scans. The method was driven mainly by local patch similarities and relied on simple affine registrations between an atlas database of the co-registered MRI/CT scan pairsmore » and the MRI scan to be converted. In this study, the authors investigate the applicability of the patch-based approach in the pelvis. This region is challenging for a method based on local similarities due to the greater inter-patient variation. The authors benchmark the method against a baseline pCT strategy where all voxels inside the body contour are assigned a water-equivalent bulk density. Furthermore, the authors implement a parallelized approximate patch search strategy to speed up the pCT generation time to a more clinically relevant level. Methods: The data consisted of CT and T{sub 1}-weighted MRI scans of 10 prostate patients. pCTs were generated using an approximate patch search algorithm in a leave-one-out fashion and compared with the CT using frequently described metrics such as the voxel-wise mean absolute error (MAE{sub vox}) and the deviation in water-equivalent path lengths. Furthermore, the dosimetric accuracy was tested for a volumetric modulated arc therapy plan using dose–volume histogram (DVH) point deviations and γ-index analysis. Results: The patch-based approach had an average MAE{sub vox} of 54 HU; median deviations of less than 0.4% in relevant DVH points and a γ-index pass rate of 0.97 using a 1%/1 mm criterion. The patch-based approach showed a significantly better performance than the baseline water pCT in almost all metrics. The approximate patch search strategy was 70x faster than a brute-force search, with an average prediction time of 20.8 min. Conclusions: The authors showed that a patch-based method based on affine registrations and T{sub 1}-weighted MRI could generate accurate pCTs of the pelvis. The main source of differences between pCT and CT was positional changes of air pockets and body outline.« less

MRI vs. CT for orthodontic applications: comparison of two MRI protocols and three CT (multislice, cone-beam, industrial) technologies.

PubMed

Detterbeck, Andreas; Hofmeister, Michael; Hofmann, Elisabeth; Haddad, Daniel; Weber, Daniel; Hölzing, Astrid; Zabler, Simon; Schmid, Matthias; Hiller, Karl-Heinz; Jakob, Peter; Engel, Jens; Hiller, Jochen; Hirschfelder, Ursula

2016-07-01

To examine the relative usefulness and suitability of magnetic resonance imaging (MRI) in daily clinical practice as compared to various technologies of computed tomography (CT) in addressing questions of orthodontic interest. Three blinded raters evaluated 2D slices and 3D reconstructions created from scans of two pig heads. Five imaging modalities were used, including three CT technologies-multislice (MSCT), cone-beam CT (CBCT), and industrial (µCT)-and two MRI protocols with different scan durations. Defined orthodontic parameters were rated one by one on the 2D slices and the 3D reconstructions, followed by final overall ratings for each modality. A mixed linear model was used for statistical analysis. Based on the 2D slices, the parameter of visualizing tooth-germ topography did not yield any significantly different ratings for MRI versus any of the CT scans. While some ratings for the other parameters did involve significant differences, how these should be interpreted depends greatly on the relevance of each parameter. Based on the 3D reconstructions, the only significant difference between technologies was noted for the parameter of visualizing root-surface morphology. Based on the final overall ratings, the imaging performance of the standard MRI protocol was noninferior to the performance of the three CT technologies. On comparing the imaging performance of MRI and CT scans, it becomes clear that MRI has a huge potential for applications in daily clinical practice. Given its additional benefits of a good contrast ratio and complete absence of ionizing radiation, further studies are needed to explore this clinical potential in greater detail.

Cost-Effectiveness of Diagnostic Strategies for Suspected Scaphoid Fractures.

PubMed

Yin, Zhong-Gang; Zhang, Jian-Bing; Gong, Ke-Tong

2015-08-01

The aim of this study was to assess the cost effectiveness of multiple competing diagnostic strategies for suspected scaphoid fractures. With published data, the authors created a decision-tree model simulating the diagnosis of suspected scaphoid fractures. Clinical outcomes, costs, and cost effectiveness of immediate computed tomography (CT), day 3 magnetic resonance imaging (MRI), day 3 bone scan, week 2 radiographs alone, week 2 radiographs-CT, week 2 radiographs-MRI, week 2 radiographs-bone scan, and immediate MRI were evaluated. The primary clinical outcome was the detection of scaphoid fractures. The authors adopted societal perspective, including both the costs of healthcare and the cost of lost productivity. The incremental cost-effectiveness ratio (ICER), which expresses the incremental cost per incremental scaphoid fracture detected using a strategy, was calculated to compare these diagnostic strategies. Base case analysis, 1-way sensitivity analyses, and "worst case scenario" and "best case scenario" sensitivity analyses were performed. In the base case, the average cost per scaphoid fracture detected with immediate CT was $2553. The ICER of immediate MRI and day 3 MRI compared with immediate CT was $7483 and $32,000 per scaphoid fracture detected, respectively. The ICER of week 2 radiographs-MRI was around $170,000. Day 3 bone scan, week 2 radiographs alone, week 2 radiographs-CT, and week 2 radiographs-bone scan strategy were dominated or extendedly dominated by MRI strategies. The results were generally robust in multiple sensitivity analyses. Immediate CT and MRI were the most cost-effective strategies for diagnosing suspected scaphoid fractures. Economic and Decision Analyses Level II. See Instructions for Authors for a complete description of levels of evidence.

Location of core diagnostic information across various sequences in brain MRI and implications for efficiency of MRI scanner utilization.

PubMed

Sharma, Aseem; Chatterjee, Arindam; Goyal, Manu; Parsons, Matthew S; Bartel, Seth

2015-04-01

Targeting redundancy within MRI can improve its cost-effective utilization. We sought to quantify potential redundancy in our brain MRI protocols. In this retrospective review, we aggregated 207 consecutive adults who underwent brain MRI and reviewed their medical records to document clinical indication, core diagnostic information provided by MRI, and its clinical impact. Contributory imaging abnormalities constituted positive core diagnostic information whereas absence of imaging abnormalities constituted negative core diagnostic information. The senior author selected core sequences deemed sufficient for extraction of core diagnostic information. For validating core sequences selection, four readers assessed the relative ease of extracting core diagnostic information from the core sequences. Potential redundancy was calculated by comparing the average number of core sequences to the average number of sequences obtained. Scanning had been performed using 9.4±2.8 sequences over 37.3±12.3 minutes. Core diagnostic information was deemed extractable from 2.1±1.1 core sequences, with an assumed scanning time of 8.6±4.8 minutes, reflecting a potential redundancy of 74.5%±19.1%. Potential redundancy was least in scans obtained for treatment planning (14.9%±25.7%) and highest in scans obtained for follow-up of benign diseases (81.4%±12.6%). In 97.4% of cases, all four readers considered core diagnostic information to be either easily extractable from core sequences or the ease to be equivalent to that from the entire study. With only one MRI lacking clinical impact (0.48%), overutilization did not seem to contribute to potential redundancy. High potential redundancy that can be targeted for more efficient scanner utilization exists in brain MRI protocols.

Presurgical functional magnetic resonance imaging in patients with brain tumors.

PubMed

Ravn, Søren; Holmberg, Mats; Sørensen, Preben; Frokjaer, Jens B; Carl, Jesper

2016-01-01

Clinical functional magnetic resonance imaging (fMRI) is still an upcoming diagnostic tool because it is time-consuming to perform the post-scan calculations and interpretations. A standardized and easily used method for the clinical assessment of fMRI scans could decrease the workload and make fMRI more attractive for clinical use. To evaluate a standardized clinical approach for distance measurement between benign brain tumors and eloquent cortex in terms of the ability to predict pre- and postoperative neurological deficits after intraoperative neuronavigation-assisted surgery. A retrospective study of 34 patients. The fMRI data were reanalyzed using a standardized distance measurement procedure combining data from both fMRI and three-dimensional T1 MRI scans. The pre- and postoperative neurological status of each patient was obtained from hospital records. Data analysis was performed using logistic regression analysis to determine whether the distance measured between the tumor margin and fMRI activity could serve as a predictor for neurological deficits. An odds ratio of 0.89 mm(-1) (P = 0.03) was found between the risk of preoperative neurological motor deficits and the tumor-fMRI distance. An odds ratio of 0.82 mm(-1) (P = 0.04) was found between the risk of additional postoperative neurological motor deficits and the tumor-fMRI distance. The tumor was radically removed in 10 cases; five patients experienced additional postoperative motor deficits (tumor-fMRI distance <18 mm) and five did not (tumor-fMRI distance >18 mm) (P = 0.008). This study indicates that the distance measured between the tumor margin and fMRI activation could serve as a valuable predictor of neurological motor deficits. © The Foundation Acta Radiologica 2014.

Positron emission tomography/magnetic resonance imaging (PET/MRI): An update and initial experience at HC-FMUSP.

PubMed

Queiroz, Marcelo A; Barbosa, Felipe de Galiza; Buchpiguel, Carlos Alberto; Cerri, Giovanni Guido

2018-01-01

The new technology of PET/MRI is a prototype of hybrid imaging, allowing for the combination of molecular data from PET scanning and morphofunctional information derived from MRI scanning. Recent advances regarding the technical aspects of this device, especially after the development of MRI-compatible silicon photomultipliers of PET, permitted an increase in the diagnostic performance of PET/MRI translated into dose reduction and higher imaging quality. Among several clinical applications, PET/MRI gains ground initially in oncology, where MRI per se plays an essential role in the assessment of primary tumors (which is limited in the case of PET/CT), including prostate, rectal and gynecological tumors. On the other hand, the evaluation of the lungs remains an enigma although new MRI sequences are being designed to overcome this. More clinical indications of PET/MRI are seen in the fields of neurology, cardiology and inflammatory processes, and the use of PET/MRI also opens perspectives for pediatric populations as it involves very low radiation exposure. Our review aimed to highlight the current indications of PET/MRI and discuss the challenges and perspectives of PET/MRI at HC-FMUSP.

[3 Tesla MRI: successful results with higher field strengths].

PubMed

Schmitt, F; Grosu, D; Mohr, C; Purdy, D; Salem, K; Scott, K T; Stoeckel, B

2004-01-01

The recent development of 3 Tesla MRI (3T MRI) has been fueled by promise of increased signal-to-noise ratio(SNR). Many are excited about the opportunity to not only use the increased SNR for clearer images, but also the chance to exchange it for better resolution or faster scans. These possibilities have caused a rapid increase in the market for 3T MRI, where the faster scanning tips an already advantageous economic outlook in favor of the user. As a result, the global market for 3T has grown from a research only market just a few years ago to an ever-increasing clinically oriented customer base. There are, however, significant obstacles to 3T MRI presented by the physics at higher field strengths. For example, the T1 relaxation times are prolonged with increasing magnet field strength. Further, the increased RF-energy deposition (SAR), the larger the chemical shift and the stronger susceptibility effect have to be considered as challenges. It is critical that one looks at both the advantages and disadvantages of using 3T. While there are many issues to address aand a number of different methods for doing so, to properly tackle each of these concerns will take time and effort on the part od researchers and clinicians. The optimization of 3T MRI scanning will have to be a combined effort, though much of the work to date has been in neuroimaging. Multiple applications have been explored in addition to clinical anatomical imaging, where resolution is improved showing structure in the brain never seen before in human MRI. Body and cardiac imaging provide a great challenge but are also achievable at 3T. As an example, the full range of clinical applications currently achieved on today's state-of-the-art 1.5T cardiac MR scanners has also been demonstrated at 3T. In the body, the full range of contrast is available over large fields of view allowing whole liver studies in the clinic or, as needed, one may choose a smaller field of view for high-resolution imaging of the pancreas. The ability to increase resolution for musculoskeletal imaging has provided previously unseen detail. Bone structure, cartilage, and tendons and ligaments can be clearly visualized and pathology more easily detected due to an increased image quality. As the increase in field strength continues, a push to look at 7T has begun. The design philosophy is to keep the system as similar as possible, while changing only the frequency-dependent components. To date, both animal and human imaging have been performed on a whole body 7T scanner. Results show promise for both detailed imaging and functional MRI, but the road ahead is too long to be able to predict where it will end. The move toward higher field strengths is an exciting adventure in which 3T plays the role of trailblazer.

Stereoscopic virtual reality models for planning tumor resection in the sellar region.

PubMed

Wang, Shou-sen; Zhang, Shang-ming; Jing, Jun-jie

2012-11-28

It is difficult for neurosurgeons to perceive the complex three-dimensional anatomical relationships in the sellar region. To investigate the value of using a virtual reality system for planning resection of sellar region tumors. The study included 60 patients with sellar tumors. All patients underwent computed tomography angiography, MRI-T1W1, and contrast enhanced MRI-T1W1 image sequence scanning. The CT and MRI scanning data were collected and then imported into a Dextroscope imaging workstation, a virtual reality system that allows structures to be viewed stereoscopically. During preoperative assessment, typical images for each patient were chosen and printed out for use by the surgeons as references during surgery. All sellar tumor models clearly displayed bone, the internal carotid artery, circle of Willis and its branches, the optic nerve and chiasm, ventricular system, tumor, brain, soft tissue and adjacent structures. Depending on the location of the tumors, we simulated the transmononasal sphenoid sinus approach, transpterional approach, and other approaches. Eleven surgeons who used virtual reality models completed a survey questionnaire. Nine of the participants said that the virtual reality images were superior to other images but that other images needed to be used in combination with the virtual reality images. The three-dimensional virtual reality models were helpful for individualized planning of surgery in the sellar region. Virtual reality appears to be promising as a valuable tool for sellar region surgery in the future.

[18F]-Fluoro-Deoxy-Glucose Positron Emission Tomography Scan Should Be Obtained Early in Cases of Autoimmune Encephalitis

PubMed Central

Sarwal, A.; Hantus, S.

2016-01-01

Introduction. Autoimmune encephalitis (AE) is a clinically challenging diagnosis with nonspecific neurological symptoms. Prompt diagnosis is important and often relies on neuroimaging. We present a case series of AE highlighting the importance of an early [18F]-fluoro-deoxy-glucose positron emission tomography (FDG-PET) scan. Methods. Retrospective review of seven consecutive cases of autoimmune encephalitis. Results. All patients had both magnetic resonance imaging (MRI) and FDG-PET scans. Initial clinical presentations included altered mental status and/or new onset seizures. Six cases had serum voltage-gated potassium channel (VGKC) antibody and one had serum N-methyl-D-aspartate (NMDA) antibody. MRI of brain showed mesial temporal lobe hyperintensity in five cases of VGKC. The other two patients with VGKC or NMDA AE had restiform body hyperintensity on MRI brain or a normal MRI, respectively. Mesial temporal lobe hypermetabolism was noted in three cases on FDG-PET, despite initial unremarkable MRI. Malignancy workup was negative in all patients. Conclusion. A high index of suspicion for AE should be maintained in patients presenting with cognitive symptoms, seizures, and limbic changes on neuroimaging. In cases with normal initial brain MRI, FDG-PET can be positive. Additionally, extralimbic hyperintensity on MRI may also be observed. PMID:27559482

Vessel wall characterization using quantitative MRI: what's in a number?

PubMed

Coolen, Bram F; Calcagno, Claudia; van Ooij, Pim; Fayad, Zahi A; Strijkers, Gustav J; Nederveen, Aart J

2018-02-01

The past decade has witnessed the rapid development of new MRI technology for vessel wall imaging. Today, with advances in MRI hardware and pulse sequences, quantitative MRI of the vessel wall represents a real alternative to conventional qualitative imaging, which is hindered by significant intra- and inter-observer variability. Quantitative MRI can measure several important morphological and functional characteristics of the vessel wall. This review provides a detailed introduction to novel quantitative MRI methods for measuring vessel wall dimensions, plaque composition and permeability, endothelial shear stress and wall stiffness. Together, these methods show the versatility of non-invasive quantitative MRI for probing vascular disease at several stages. These quantitative MRI biomarkers can play an important role in the context of both treatment response monitoring and risk prediction. Given the rapid developments in scan acceleration techniques and novel image reconstruction, we foresee the possibility of integrating the acquisition of multiple quantitative vessel wall parameters within a single scan session.

Optical textile tests MRI patients from afar

NASA Astrophysics Data System (ADS)

Gould, Paula

2008-11-01

Researchers in Europe have developed a wearable textile fitted with optical sensors that could be used to remotely monitor a patient's breathing patterns while they undergo magnetic resonance imaging (MRI) scans. The new textile will allow medical staff to keep an eye on children and other vulnerable patients who often have to be calmed with sedatives or anaesthetic drugs to keep them still during a scan. The technique will be particularly useful if proposed European Union (EU) legislation that is designed to protect medical staff from being exposed to the high magnetic fields of MRI systems comes into force in 2012. The new rules would prevent nurses from being in the room where the scan is taking place.

Coil compression in simultaneous multislice functional MRI with concentric ring slice-GRAPPA and SENSE.

PubMed

Chu, Alan; Noll, Douglas C

2016-10-01

Simultaneous multislice (SMS) imaging is a useful way to accelerate functional magnetic resonance imaging (fMRI). As acceleration becomes more aggressive, an increasingly larger number of receive coils are required to separate the slices, which significantly increases the computational burden. We propose a coil compression method that works with concentric ring non-Cartesian SMS imaging and should work with Cartesian SMS as well. We evaluate the method on fMRI scans of several subjects and compare it to standard coil compression methods. The proposed method uses a slice-separation k-space kernel to simultaneously compress coil data into a set of virtual coils. Five subjects were scanned using both non-SMS fMRI and SMS fMRI with three simultaneous slices. The SMS fMRI scans were processed using the proposed method, along with other conventional methods. Code is available at https://github.com/alcu/sms. The proposed method maintained functional activation with a fewer number of virtual coils than standard SMS coil compression methods. Compression of non-SMS fMRI maintained activation with a slightly lower number of virtual coils than the proposed method, but does not have the acceleration advantages of SMS fMRI. The proposed method is a practical way to compress and reconstruct concentric ring SMS data and improves the preservation of functional activation over standard coil compression methods in fMRI. Magn Reson Med 76:1196-1209, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Seven tesla MRI improves detection of focal cortical dysplasia in patients with refractory focal epilepsy.

PubMed

Veersema, Tim J; Ferrier, Cyrille H; van Eijsden, Pieter; Gosselaar, Peter H; Aronica, Eleonora; Visser, Fredy; Zwanenburg, Jaco M; de Kort, Gerard A P; Hendrikse, Jeroen; Luijten, Peter R; Braun, Kees P J

2017-06-01

The aim of this study is to determine whether the use of 7 tesla (T) MRI in clinical practice leads to higher detection rates of focal cortical dysplasias in possible candidates for epilepsy surgery. In our center patients are referred for 7 T MRI if lesional focal epilepsy is suspected, but no abnormalities are detected at one or more previous, sufficient-quality lower-field MRI scans, acquired with a dedicated epilepsy protocol, or when concealed pathology is suspected in combination with MR-visible mesiotemporal sclerosis-dual pathology. We assessed 40 epilepsy patients who underwent 7 T MRI for presurgical evaluation and whose scans (both 7 T and lower field) were discussed during multidisciplinary epilepsy surgery meetings that included a dedicated epilepsy neuroradiologist. We compared the conclusions of the multidisciplinary visual assessments of 7 T and lower-field MRI scans. In our series of 40 patients, multidisciplinary evaluation of 7 T MRI identified additional lesions not seen on lower-field MRI in 9 patients (23%). These findings were guiding in surgical planning. So far, 6 patients underwent surgery, with histological confirmation of focal cortical dysplasia or mild malformation of cortical development. Seven T MRI improves detection of subtle focal cortical dysplasia and mild malformations of cortical development in patients with intractable epilepsy and may therefore contribute to identification of surgical candidates and complete resection of the epileptogenic lesion, and thus to postoperative seizure freedom.

High-resolution whole-brain diffusion MRI at 7T using radiofrequency parallel transmission.

PubMed

Wu, Xiaoping; Auerbach, Edward J; Vu, An T; Moeller, Steen; Lenglet, Christophe; Schmitter, Sebastian; Van de Moortele, Pierre-François; Yacoub, Essa; Uğurbil, Kâmil

2018-03-30

Investigating the utility of RF parallel transmission (pTx) for Human Connectome Project (HCP)-style whole-brain diffusion MRI (dMRI) data at 7 Tesla (7T). Healthy subjects were scanned in pTx and single-transmit (1Tx) modes. Multiband (MB), single-spoke pTx pulses were designed to image sagittal slices. HCP-style dMRI data (i.e., 1.05-mm resolutions, MB2, b-values = 1000/2000 s/mm 2 , 286 images and 40-min scan) and data with higher accelerations (MB3 and MB4) were acquired with pTx. pTx significantly improved flip-angle detected signal uniformity across the brain, yielding ∼19% increase in temporal SNR (tSNR) averaged over the brain relative to 1Tx. This allowed significantly enhanced estimation of multiple fiber orientations (with ∼21% decrease in dispersion) in HCP-style 7T dMRI datasets. Additionally, pTx pulses achieved substantially lower power deposition, permitting higher accelerations, enabling collection of the same data in 2/3 and 1/2 the scan time or of more data in the same scan time. pTx provides a solution to two major limitations for slice-accelerated high-resolution whole-brain dMRI at 7T; it improves flip-angle uniformity, and enables higher slice acceleration relative to current state-of-the-art. As such, pTx provides significant advantages for rapid acquisition of high-quality, high-resolution truly whole-brain dMRI data. © 2018 International Society for Magnetic Resonance in Medicine.

2D and 3D MALDI-imaging: conceptual strategies for visualization and data mining.

PubMed

Thiele, Herbert; Heldmann, Stefan; Trede, Dennis; Strehlow, Jan; Wirtz, Stefan; Dreher, Wolfgang; Berger, Judith; Oetjen, Janina; Kobarg, Jan Hendrik; Fischer, Bernd; Maass, Peter

2014-01-01

3D imaging has a significant impact on many challenges in life sciences, because biology is a 3-dimensional phenomenon. Current 3D imaging-technologies (various types MRI, PET, SPECT) are labeled, i.e. they trace the localization of a specific compound in the body. In contrast, 3D MALDI mass spectrometry-imaging (MALDI-MSI) is a label-free method imaging the spatial distribution of molecular compounds. It complements 3D imaging labeled methods, immunohistochemistry, and genetics-based methods. However, 3D MALDI-MSI cannot tap its full potential due to the lack of statistical methods for analysis and interpretation of large and complex 3D datasets. To overcome this, we established a complete and robust 3D MALDI-MSI pipeline combined with efficient computational data analysis methods for 3D edge preserving image denoising, 3D spatial segmentation as well as finding colocalized m/z values, which will be reviewed here in detail. Furthermore, we explain, why the integration and correlation of the MALDI imaging data with other imaging modalities allows to enhance the interpretation of the molecular data and provides visualization of molecular patterns that may otherwise not be apparent. Therefore, a 3D data acquisition workflow is described generating a set of 3 different dimensional images representing the same anatomies. First, an in-vitro MRI measurement is performed which results in a three-dimensional image modality representing the 3D structure of the measured object. After sectioning the 3D object into N consecutive slices, all N slices are scanned using an optical digital scanner, enabling for performing the MS measurements. Scanning the individual sections results into low-resolution images, which define the base coordinate system for the whole pipeline. The scanned images conclude the information from the spatial (MRI) and the mass spectrometric (MALDI-MSI) dimension and are used for the spatial three-dimensional reconstruction of the object performed by image registration techniques. Different strategies for automatic serial image registration applied to MS datasets are outlined in detail. The third image modality is histology driven, i.e. a digital scan of the histological stained slices in high-resolution. After fusion of reconstructed scan images and MRI the slice-related coordinates of the mass spectra can be propagated into 3D-space. After image registration of scan images and histological stained images, the anatomical information from histology is fused with the mass spectra from MALDI-MSI. As a result of the described pipeline we have a set of 3 dimensional images representing the same anatomies, i.e. the reconstructed slice scans, the spectral images as well as corresponding clustering results, and the acquired MRI. Great emphasis is put on the fact that the co-registered MRI providing anatomical details improves the interpretation of 3D MALDI images. The ability to relate mass spectrometry derived molecular information with in vivo and in vitro imaging has potentially important implications. This article is part of a Special Issue entitled: Computational Proteomics in the Post-Identification Era. Guest Editors: Martin Eisenacher and Christian Stephan. Copyright © 2013. Published by Elsevier B.V.

Intranasal oxytocin, but not vasopressin, augments neural responses to toddlers in human fathers.

PubMed

Li, Ting; Chen, Xu; Mascaro, Jennifer; Haroon, Ebrahim; Rilling, James K

2017-07-01

This study investigates paternal brain function with the hope of better understanding the neural basis for variation in caregiving involvement among men. The neuropeptides oxytocin (OT) and vasopressin (AVP) are implicated in paternal caregiving in humans and other species. In a double-blind, placebo-controlled, within-subject pharmaco-functional MRI experiment, we randomized 30 fathers of 1-2year old children to receive either 24IU intranasal OT before one scan and placebo before the other scan (n=15) or 20IU intranasal AVP before one scan and placebo before the other scan (n=15). Brain function was measured with fMRI as the fathers viewed pictures of their children, unknown children and unknown adults, and as they listened to unknown infant cry stimuli. Intranasal OT, but not AVP, significantly increased the BOLD fMRI response to viewing pictures of own children within the caudate nucleus, a target of midbrain dopamine projections, as well as the dorsal anterior cingulate (dACC) and visual cortex, suggesting that intranasal oxytocin augments activation in brain regions involved in reward, empathy and attention in human fathers. OT effects also varied as a function of order of administration such that when OT was given before placebo, it increased activation within several reward-related structures (substantia nigra, ventral tegmental area, putamen) more than when it was given after placebo. Neither OT nor AVP had significant main effects on the neural response to cries. Our findings suggest that the hormonal changes associated with the transition to fatherhood are likely to facilitate increased approach motivation and empathy for children, and call for future research that evaluates the potential of OT to normalize deficits in paternal motivation, as might be found among men suffering from post-partum depression. Copyright © 2017 Elsevier Inc. All rights reserved.

WE-FG-202-07: An MRI-Based Approach to Quantify Radiation-Induced Normal Tissue Injury Applied to Trismus After Head and Neck Cancer Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thor, M; Tyagi, N; Saleh, Z

Purpose: The aim of this study was to investigate if quantitative MRI-derived metrics from four masticatory muscles could explain mouth-opening limitation/trismus following intensity-modulated radiotherapy (IMRT) for head and neck cancer (HNC). Methods: Fifteen intensity-based MRI metrics were derived from the masseter, lateral and medial pterygoid, and temporalis in T1-weighted scans acquired pre- and post gadolinium injection (T1Pre, T1Post) of 16, of in total 20, patients (8 symptomatic; 8 asymptomatic age/sex/tumor location-matched) treated with IMRT to 70 Gy (median) for HNC in 2005–2009. Trismus was defined as “≥decreased range of motion without impaired eating” (CTCAE.v.3: ≥Grade 1). Trismus status was monitoredmore » and MRI scans acquired within 1y post-RT. All MRI-derived metrics were assessed as ΔS=S(T1Pre)-S(T1Post)/S(T1Pre), and were normalized to the corresponding metric of a non-irradiated volume defined in each scan. The T1Pre structures were propagated onto the RT dose distribution, and the max and mean dose (Dmax, Dmean) were extracted. The MRI-derived metrics, Dmax, and Dmean were compared between trismus and non-trismus patients. A two-sided Wilcoxon Signed rank test-based p-value≤0.05 denoted significance. Results: For all four muscles the population mean of Dmax and Dmean was higher for patients with trismus compared to patients without trismus (ΔDmax=2.3–4.9 Gy; ΔDmean=and 2.0–3.8 Gy). The standard deviation (SD), the variance, and the minimum value (min) of ΔS were significantly (p=0.04–0.05) different between patients with and without trismus with trismus patients having significantly lower SD (population median: −0.53 vs. −0.31) and variance (−2.09 vs. −0.73) of the masseter, and significantly lower min of the medial pterygoid (−0.36 vs. −0.19). Conclusion: Quantitative MRI-derived metrics of two masticatory muscles were significantly different between patients with and without trismus following RT for HNC. These metrics could serve as image-based biomarkers to better understand the RT-induced etiology behind trismus, but should be further investigated in the complete cohort.« less

[Optimization of diagnosis indicator selection and inspection plan by 3.0T MRI in breast cancer].

PubMed

Jiang, Zhongbiao; Wang, Yunhua; He, Zhong; Zhang, Lejun; Zheng, Kai

2013-08-01

To optimize 3.0T MRI diagnosis indicator in breast cancer and to select the best MRI scan program. Totally 45 patients with breast cancers were collected, and another 35 patients with benign breast tumor served as the control group. All patients underwent 3.0T MRI, including T1- weighted imaging (T1WI), fat suppression of the T2-weighted imaging (T2WI), diffusion weighted imaging (DWI), 1H magnetic resonance spectroscopy (1H-MRS) and dynamic contrast enhanced (DCE) sequence. With operation pathology results as the gold standard in the diagnosis of breast diseases, the pathological results of benign and malignant served as dependent variables, and the diagnostic indicators of MRI were taken as independent variables. We put all the indicators of MRI examination under Logistic regression analysis, established the Logistic model, and optimized the diagnosis indicators of MRI examination to further improve MRI scan of breast cancer. By Logistic regression analysis, some indicators were selected in the equation, including the edge feature of the tumor, the time-signal intensity curve (TIC) type and the apparent diffusion coefficient (ADC) value when b=500 s/mm2. The regression equation was Logit (P)=-21.936+20.478X6+3.267X7+ 21.488X3. Valuable indicators in the diagnosis of breast cancer are the edge feature of the tumor, the TIC type and the ADC value when b=500 s/mm2. Combining conventional MRI scan, DWI and dynamic enhanced MRI is a better examination program, while MRS is the complementary program when diagnosis is difficult.

Reliability of Early Magnetic Resonance Imaging (MRI) and Necessity of Repeating MRI in Noncooled and Cooled Infants With Neonatal Encephalopathy.

PubMed

Chakkarapani, Elavazhagan; Poskitt, Kenneth J; Miller, Steven P; Zwicker, Jill G; Xu, Qi; Wong, Darren S T; Roland, Elke H; Hill, Alan; Chau, Vann

2016-04-01

In cooled newborns with encephalopathy, although late magnetic resonance imaging (MRI) scan (10-14 days of age) is reliable in predicting long-term outcome, it is unknown whether early scan (3-6 days of life) is. We compared the predominant pattern and extent of lesion between early and late MRI in 89 term neonates with neonatal encephalopathy. Forty-three neonates (48%) were cooled. The predominant pattern of lesions and the extent of lesion in the watershed region agreed near perfectly in noncooled (kappa = 0.94; k = 0.88) and cooled (k = 0.89; k = 0.87) infants respectively. There was perfect agreement in the extent of lesion in the basal nuclei in noncooled infants (k = 0.83) and excellent agreement in cooled infants (k = 0.67). Changes in extent of lesions on late MRI occurred in 19 of 89 infants, with higher risk in infants with hypoglycemia and moderate-severe lesions in basal nuclei. In most term neonates with neonatal encephalopathy, early MRI (relative to late scan) robustly predicts the predominant pattern and extent of injury. © The Author(s) 2015.

Atlas-Guided Segmentation of Vervet Monkey Brain MRI

PubMed Central

Fedorov, Andriy; Li, Xiaoxing; Pohl, Kilian M; Bouix, Sylvain; Styner, Martin; Addicott, Merideth; Wyatt, Chris; Daunais, James B; Wells, William M; Kikinis, Ron

2011-01-01

The vervet monkey is an important nonhuman primate model that allows the study of isolated environmental factors in a controlled environment. Analysis of monkey MRI often suffers from lower quality images compared with human MRI because clinical equipment is typically used to image the smaller monkey brain and higher spatial resolution is required. This, together with the anatomical differences of the monkey brains, complicates the use of neuroimage analysis pipelines tuned for human MRI analysis. In this paper we developed an open source image analysis framework based on the tools available within the 3D Slicer software to support a biological study that investigates the effect of chronic ethanol exposure on brain morphometry in a longitudinally followed population of male vervets. We first developed a computerized atlas of vervet monkey brain MRI, which was used to encode the typical appearance of the individual brain structures in MRI and their spatial distribution. The atlas was then used as a spatial prior during automatic segmentation to process two longitudinal scans per subject. Our evaluation confirms the consistency and reliability of the automatic segmentation. The comparison of atlas construction strategies reveals that the use of a population-specific atlas leads to improved accuracy of the segmentation for subcortical brain structures. The contribution of this work is twofold. First, we describe an image processing workflow specifically tuned towards the analysis of vervet MRI that consists solely of the open source software tools. Second, we develop a digital atlas of vervet monkey brain MRIs to enable similar studies that rely on the vervet model. PMID:22253661

Reliability of the echoMRI infant system for water and fat measurements in newborns

USDA-ARS?s Scientific Manuscript database

The precision and accuracy of a quantitative magnetic resonance (EchoMRI Infants) system in newborns were determined. Canola oil and drinking water phantoms (increments of 10 g to 1.9 kg) were scanned four times. Instrument reproducibility was assessed from three scans (within 10 minutes) in 42 heal...

Design and simulation of a 800 Mbit/s data link for magnetic resonance imaging wearables.

PubMed

Vogt, Christian; Buthe, Lars; Petti, Luisa; Cantarella, Giuseppe; Munzenrieder, Niko; Daus, Alwin; Troster, Gerhard

2015-08-01

This paper presents the optimization of electronic circuitry for operation in the harsh electro magnetic (EM) environment during a magnetic resonance imaging (MRI) scan. As demonstrator, a device small enough to be worn during the scan is optimized. Based on finite element method (FEM) simulations, the induced current densities due to magnetic field changes of 200 T s(-1) were reduced from 1 × 10(10) A m(-2) by one order of magnitude, predicting error-free operation of the 1.8V logic employed. The simulations were validated using a bit error rate test, which showed no bit errors during a MRI scan sequence. Therefore, neither the logic, nor the utilized 800 Mbit s(-1) low voltage differential swing (LVDS) data link of the optimized wearable device were significantly influenced by the EM interference. Next, the influence of ferro-magnetic components on the static magnetic field and consequently the image quality was simulated showing a MRI image loss with approximately 2 cm radius around a commercial integrated circuit of 1×1 cm(2). This was successively validated by a conventional MRI scan.

Deformable templates guided discriminative models for robust 3D brain MRI segmentation.

PubMed

Liu, Cheng-Yi; Iglesias, Juan Eugenio; Tu, Zhuowen

2013-10-01

Automatically segmenting anatomical structures from 3D brain MRI images is an important task in neuroimaging. One major challenge is to design and learn effective image models accounting for the large variability in anatomy and data acquisition protocols. A deformable template is a type of generative model that attempts to explicitly match an input image with a template (atlas), and thus, they are robust against global intensity changes. On the other hand, discriminative models combine local image features to capture complex image patterns. In this paper, we propose a robust brain image segmentation algorithm that fuses together deformable templates and informative features. It takes advantage of the adaptation capability of the generative model and the classification power of the discriminative models. The proposed algorithm achieves both robustness and efficiency, and can be used to segment brain MRI images with large anatomical variations. We perform an extensive experimental study on four datasets of T1-weighted brain MRI data from different sources (1,082 MRI scans in total) and observe consistent improvement over the state-of-the-art systems.

Longitudinal decline in structural networks predicts dementia in cerebral small vessel disease

PubMed Central

Lawrence, Andrew J.; Zeestraten, Eva A.; Benjamin, Philip; Lambert, Christian P.; Morris, Robin G.; Barrick, Thomas R.

2018-01-01

Objective To determine whether longitudinal change in white matter structural network integrity predicts dementia and future cognitive decline in cerebral small vessel disease (SVD). To investigate whether network disruption has a causal role in cognitive decline and mediates the association between conventional MRI markers of SVD with both cognitive decline and dementia. Methods In the prospective longitudinal SCANS (St George's Cognition and Neuroimaging in Stroke) Study, 97 dementia-free individuals with symptomatic lacunar stroke were followed with annual MRI for 3 years and annual cognitive assessment for 5 years. Conversion to dementia was recorded. Structural networks were constructed from diffusion tractography using a longitudinal registration pipeline, and network global efficiency was calculated. Linear mixed-effects regression was used to assess change over time. Results Seventeen individuals (17.5%) converted to dementia, and significant decline in global cognition occurred (p = 0.0016). Structural network measures declined over the 3-year MRI follow-up, but the degree of change varied markedly between individuals. The degree of reductions in network global efficiency was associated with conversion to dementia (B = −2.35, odds ratio = 0.095, p = 0.00056). Change in network global efficiency mediated much of the association of conventional MRI markers of SVD with cognitive decline and progression to dementia. Conclusions Network disruption has a central role in the pathogenesis of cognitive decline and dementia in SVD. It may be a useful disease marker to identify that subgroup of patients with SVD who progress to dementia. PMID:29695593

Accelerated Age-Dependent Hippocampal Volume Loss in Parkinson Disease With Mild Cognitive Impairment.

PubMed

Schneider, Christine B; Donix, Markus; Linse, Katharina; Werner, Annett; Fauser, Mareike; Klingelhoefer, Lisa; Löhle, Matthias; von Kummer, Rüdiger; Reichmann, Heinz; Storch, Alexander

2017-09-01

Patients with Parkinson disease are at high risk of developing dementia. During the course of the disease, a substantial number of patients will experience a cognitive decline, indicating the dynamics of the underlying neuropathology. Magnetic resonance imaging (MRI) has become increasingly useful for identifying structural characteristics in radiological brain anatomy existing prior to clinical symptoms. Whether these changes reflect pathology, whether they are aging related, or both often remains unclear. We hypothesized that aging-associated brain structural changes would be more pronounced in the hippocampal region among patients with Parkinson disease having mild cognitive deficits relative to cognitively unimpaired patients. Using MRI, we investigated 30 cognitively healthy patients with Parkinson disease and 33 patients with nondemented Parkinson disease having mild cognitive impairment. All participants underwent structural MRI scanning and extensive clinical and neuropsychological assessments. Irrespective of the study participants' cognitive status, older age was associated with reduced cortical thickness in various neocortical regions. Having mild cognitive impairment was not associated with an increased rate of cortical thinning or volume loss in these regions, except in the hippocampus bilaterally. Patients with Parkinson disease having mild cognitive impairment show an accelerated age-dependent hippocampal volume loss when compared with cognitively healthy patients with Parkinson disease. This may indicate pathological processes in a key region for memory functioning in patients with Parkinson disease at risk of developing dementia. Structural MRI of the hippocampal region could potentially contribute to identifying patients who should receive early treatment aimed at delaying the clinical onset of dementia.

Voxel-based Gaussian naïve Bayes classification of ischemic stroke lesions in individual T1-weighted MRI scans.

PubMed

Griffis, Joseph C; Allendorfer, Jane B; Szaflarski, Jerzy P

2016-01-15

Manual lesion delineation by an expert is the standard for lesion identification in MRI scans, but it is time-consuming and can introduce subjective bias. Alternative methods often require multi-modal MRI data, user interaction, scans from a control population, and/or arbitrary statistical thresholding. We present an approach for automatically identifying stroke lesions in individual T1-weighted MRI scans using naïve Bayes classification. Probabilistic tissue segmentation and image algebra were used to create feature maps encoding information about missing and abnormal tissue. Leave-one-case-out training and cross-validation was used to obtain out-of-sample predictions for each of 30 cases with left hemisphere stroke lesions. Our method correctly predicted lesion locations for 30/30 un-trained cases. Post-processing with smoothing (8mm FWHM) and cluster-extent thresholding (100 voxels) was found to improve performance. Quantitative evaluations of post-processed out-of-sample predictions on 30 cases revealed high spatial overlap (mean Dice similarity coefficient=0.66) and volume agreement (mean percent volume difference=28.91; Pearson's r=0.97) with manual lesion delineations. Our automated approach agrees with manual tracing. It provides an alternative to automated methods that require multi-modal MRI data, additional control scans, or user interaction to achieve optimal performance. Our fully trained classifier has applications in neuroimaging and clinical contexts. Copyright © 2015 Elsevier B.V. All rights reserved.

Recent progress and outstanding issues in motion correction in resting state fMRI.

PubMed

Power, Jonathan D; Schlaggar, Bradley L; Petersen, Steven E

2015-01-15

The purpose of this review is to communicate and synthesize recent findings related to motion artifact in resting state fMRI. In 2011, three groups reported that small head movements produced spurious but structured noise in brain scans, causing distance-dependent changes in signal correlations. This finding has prompted both methods development and the re-examination of prior findings with more stringent motion correction. Since 2011, over a dozen papers have been published specifically on motion artifact in resting state fMRI. We will attempt to distill these papers to their most essential content. We will point out some aspects of motion artifact that are easily or often overlooked. Throughout the review, we will highlight gaps in current knowledge and avenues for future research. Copyright © 2014 Elsevier Inc. All rights reserved.

Machine learning for the automatic localisation of foetal body parts in cine-MRI scans

NASA Astrophysics Data System (ADS)

Bowles, Christopher; Nowlan, Niamh C.; Hayat, Tayyib T. A.; Malamateniou, Christina; Rutherford, Mary; Hajnal, Joseph V.; Rueckert, Daniel; Kainz, Bernhard

2015-03-01

Being able to automate the location of individual foetal body parts has the potential to dramatically reduce the work required to analyse time resolved foetal Magnetic Resonance Imaging (cine-MRI) scans, for example, for use in the automatic evaluation of the foetal development. Currently, manual preprocessing of every scan is required to locate body parts before analysis can be performed, leading to a significant time overhead. With the volume of scans becoming available set to increase as cine-MRI scans become more prevalent in clinical practice, this stage of manual preprocessing is a bottleneck, limiting the data available for further analysis. Any tools which can automate this process will therefore save many hours of research time and increase the rate of new discoveries in what is a key area in understanding early human development. Here we present a series of techniques which can be applied to foetal cine-MRI scans in order to first locate and then differentiate between individual body parts. A novel approach to maternal movement suppression and segmentation using Fourier transforms is put forward as a preprocessing step, allowing for easy extraction of short movements of individual foetal body parts via the clustering of optical flow vector fields. These body part movements are compared to a labelled database and probabilistically classified before being spatially and temporally combined to give a final estimate for the location of each body part.

Assessing the Risks Associated with MRI in Patients with a Pacemaker or Defibrillator.

PubMed

Russo, Robert J; Costa, Heather S; Silva, Patricia D; Anderson, Jeffrey L; Arshad, Aysha; Biederman, Robert W W; Boyle, Noel G; Frabizzio, Jennifer V; Birgersdotter-Green, Ulrika; Higgins, Steven L; Lampert, Rachel; Machado, Christian E; Martin, Edward T; Rivard, Andrew L; Rubenstein, Jason C; Schaerf, Raymond H M; Schwartz, Jennifer D; Shah, Dipan J; Tomassoni, Gery F; Tominaga, Gail T; Tonkin, Allison E; Uretsky, Seth; Wolff, Steven D

2017-02-23

The presence of a cardiovascular implantable electronic device has long been a contraindication for the performance of magnetic resonance imaging (MRI). We established a prospective registry to determine the risks associated with MRI at a magnetic field strength of 1.5 tesla for patients who had a pacemaker or implantable cardioverter-defibrillator (ICD) that was "non-MRI-conditional" (i.e., not approved by the Food and Drug Administration for MRI scanning). Patients in the registry were referred for clinically indicated nonthoracic MRI at a field strength of 1.5 tesla. Devices were interrogated before and after MRI with the use of a standardized protocol and were appropriately reprogrammed before the scanning. The primary end points were death, generator or lead failure, induced arrhythmia, loss of capture, or electrical reset during the scanning. The secondary end points were changes in device settings. MRI was performed in 1000 cases in which patients had a pacemaker and in 500 cases in which patients had an ICD. No deaths, lead failures, losses of capture, or ventricular arrhythmias occurred during MRI. One ICD generator could not be interrogated after MRI and required immediate replacement; the device had not been appropriately programmed per protocol before the MRI. We observed six cases of self-terminating atrial fibrillation or flutter and six cases of partial electrical reset. Changes in lead impedance, pacing threshold, battery voltage, and P-wave and R-wave amplitude exceeded prespecified thresholds in a small number of cases. Repeat MRI was not associated with an increase in adverse events. In this study, device or lead failure did not occur in any patient with a non-MRI-conditional pacemaker or ICD who underwent clinically indicated nonthoracic MRI at 1.5 tesla, was appropriately screened, and had the device reprogrammed in accordance with the prespecified protocol. (Funded by St. Jude Medical and others; MagnaSafe ClinicalTrials.gov number, NCT00907361 .).

Optimizing MRI Logistics: Focused Process Improvements Can Increase Throughput in an Academic Radiology Department.

PubMed

O'Brien, Jeremy J; Stormann, Jeremy; Roche, Kelli; Cabral-Goncalves, Ines; Monks, Annamarie; Hallett, Donna; Mortele, Koenraad J

2017-02-01

The purpose of this study was to describe and evaluate the effect of focused process improvements on protocol selection and scheduling in the MRI division of a busy academic medical center, as measured by examination and room times, magnet fill rate, and potential revenue increases and cost savings to the department. Focused process improvements, led by a multidisciplinary team at a large academic medical center, were directed at streamlining MRI protocols and optimizing matching protocol ordering to scheduling while maintaining or improving image quality. Data were collected before (June 2013) and after (March 2015) implementation of focused process improvements and divided by subspecialty on type of examination, allotted examination time, actual examination time, and MRI parameters. Direct and indirect costs were compiled and analyzed in consultation with the business department. Data were compared with evaluated effects on selected outcome and efficiency measures, as well as revenue and cost considerations. Statistical analysis was performed using a t test. During the month of June 2013, 2145 MRI examinations were performed at our center; 2702 were performed in March 2015. Neuroradiology examinations were the most common (59% in June 2013, 56% in March 2015), followed by body examinations (25% and 27%). All protocols and parameters were analyzed and streamlined for each examination, with slice thickness, TR, and echo train length among the most adjusted parameters. Mean time per examination decreased from 43.4 minutes to 36.7 minutes, and mean room time per patient decreased from 46.3 to 43.6 minutes (p = 0.009). Potential revenue from increased throughput may yield up to $3 million yearly (at $800 net revenue per scan) or produce cost savings if the facility can reduce staffed scanner hours or the number of scanners in its fleet. Actual revenue and expense impacts depend on the facility's fixed and variable cost structure, payer contracts, MRI fleet composition, and unmet MRI demand. Focused process improvements in selecting MRI protocols and scheduling examinations significantly increased throughput in the MRI division, thereby increasing capacity and revenue. Shorter scan and department times may also improve patient experience.

Structural correlates of active-staining following magnetic resonance microscopy in the mouse brain

PubMed Central

Cleary, Jon O.; Wiseman, Frances K.; Norris, Francesca C.; Price, Anthony N.; Choy, ManKin; Tybulewicz, Victor L.J.; Ordidge, Roger J.; Brandner, Sebastian; Fisher, Elizabeth M.C.; Lythgoe, Mark F.

2011-01-01

Extensive worldwide efforts are underway to produce knockout mice for each of the ~ 25,000 mouse genes, which may give new insights into the underlying pathophysiology of neurological disease. Microscopic magnetic resonance imaging (μMRI) is a key method for non-invasive morphological phenotyping, capable of producing high-resolution 3D images of ex-vivo brains, after fixation with an MR contrast agent. These agents have been suggested to act as active-stains, enhancing structures not normally visible on MRI. In this study, we investigated the structural correlates of the MRI agent Gd-DTPA, together with the optimal preparation and scan parameters for contrast-enhanced gradient-echo imaging of the mouse brain. We observed that in-situ preparation was preferential to ex-situ due to the degree of extraction damage. In-situ brains scanned with optimised parameters, enabled images with a high signal-to-noise-ratio (SNR ~ 30) and comprehensive anatomical delineation. Direct correlation of the MR brain structures to histology, detailed fine histoarchitecture in the cortex, cerebellum, olfactory bulb and hippocampus. Neurofilament staining demonstrated that regions of negative MR contrast strongly correlated to myelinated white-matter structures, whilst structures of more positive MR contrast corresponded to areas with high grey matter content. We were able to identify many sub-regions, particularly within the hippocampus, such as the unmyelinated mossy fibres (stratum lucidum) and their region of synapse in the stratum pyramidale, together with the granular layer of the dentate gyrus, an area of densely packed cell bodies, which was clearly visible as a region of hyperintensity. This suggests that cellular structure influences the site-specific distribution of the MR contrast agent, resulting in local variations in T2*, which leads to enhanced tissue discrimination. Our findings provide insights not only into the cellular distribution and mechanism of MR active-staining, but also allow for three dimensional analysis, which enables interpretation of magnetic resonance microscopy brain data and highlights cellular structure for investigation of disease processes in development and disease. PMID:21310249

Serial brain MRI and ultrasound findings: relation to gestational age, bilirubin level, neonatal neurologic status and neurodevelopmental outcome in infants at risk of kernicterus.

PubMed

Gkoltsiou, Konstantina; Tzoufi, Meropi; Counsell, Serena; Rutherford, Mary; Cowan, Frances

2008-12-01

To describe cranial ultrasound (cUS) and magnetic resonance imaging (MRI) findings in neonates at risk of kernicterus, in relation to gestational age (GA), total serum bilirubin (TSB), age at imaging and neurodevelopmental outcome. Neonates with peak TSB > 400 micromol/L and/or signs of bilirubin encephalopathy. Review of neonatal data, cUS, preterm, term and later MRI scans and neurodevelopmental outcome. 11 infants were studied, two < 31, four 34-36 and five 37-40 weeks GA. TSB levels: 235-583 micromol/L (preterms); 423-720 micromol/L (terms). Neonatal neurological examination was abnormal in 8/10. cUS showed increased basal ganglia (BG) in 4/9 infants and white matter (WM) echogenicity, lenticulostriate vasculopathy (LSV) and caudothalamic hyperechogencity/cysts (GLCs) in 5/9 infants. MRI showed abnormal signal intensity (SI) in the globus pallidum (GP) in 1/2 preterm, 8/9 term and 9/11 later scans. Abnormal WM SI occurred in 2 preterm, 7 term and 10/11 later scans. Seven infants developed athetoid/dystonic cerebral palsy (CP) and 6 hearing loss (HL). Adverse outcome was associated with abnormal BG on cUS (3/4 CP, 4/4 HL), with high SI in GP (7/9 CP, 6/9 HL) on late T2-weighted MRI (all GA) and on T1/T2-weighted term MRI, mainly in term-born infants. WM abnormalities, GLCs and LSV did not correlate with outcome. Severe CP occurred with relatively low TSB levels in preterms but only at high levels in full-terms; HL was difficult to predict. Early scans did not reliably predict motor deficits whilst all children with CP had abnormal central grey matter on later scans. Abnormal WM was seen early suggesting primary involvement rather than change secondary to grey matter damage. Why characteristic central grey matter MRI features of kernicterus are not seen early remains unexplained.

Safety and utility of magnetic resonance imaging in patients with cardiac implantable electronic devices.

PubMed

Strom, Jordan B; Whelan, Jill B; Shen, Changyu; Zheng, Shuang Qi; Mortele, Koenraad J; Kramer, Daniel B

2017-08-01

Off-label magnetic resonance imaging (MRI) for patients with cardiac implantable electrical devices has been limited owing to concerns about safety and unclear diagnostic and prognostic utility. The purpose of this study was to define major and minor adverse events with off-label MRI scans. We prospectively evaluated patients with non-MRI-conditional cardiac implantable electrical devices referred for MRI scans under a strict clinical protocol. The primary safety outcome was incidence of major adverse events (loss of pacing, inappropriate shock or antitachycardia pacing, need for system revision, or death) or minor adverse events (inappropriate pacing, arrhythmias, power-on-reset events, heating at the generator site, or changes in device parameters at baseline or at 6 months). A total of 189 MRI scans were performed in 123 patients (63.1% [78] men; median age 70 ± 18.5 years; 56.9% [70] patients with implantable cardioverter-defibrillators; 33.3% [41] pacemaker-dependent patients) predominantly for brain or spinal conditions. A minority of scans (22.7% [43]) were performed for urgent or emergent indications. Major adverse events were rare: 1 patient with loss of pacing, no deaths, or system revisions (overall rate 0.5%; 95% confidence interval 0.01-2.91). Minor adverse events were similarly rare (overall rate 1.6%; 95% confidence interval 0.3-4.6). Nearly all studies (98.4% [186]) were interpretable, while 75.1% [142] were determined to change management according to the prespecified criteria. No clinically significant changes were observed in device parameters acutely after MRI or at 6 months as compared with baseline across all patient and device categories. Off-label MRI scans performed under a strict protocol demonstrated excellent short- and medium-term safety while providing interpretable imaging that frequently influenced clinical care. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Safety and utility of magnetic resonance imaging in patients with cardiac implantable electronic devices

PubMed Central

Strom, Jordan B.; Whelan, Jill B.; Shen, Changyu; Zheng, Shuang Qi; Mortele, Koenraad J.; Kramer, Daniel B.

2017-01-01

BACKGROUND Off-label magnetic resonance imaging (MRI) for patients with cardiac implantable electrical devices has been limited owing to concerns about safety and unclear diagnostic and prognostic utility. OBJECTIVE The purpose of this study was to define major and minor adverse events with off-label MRI scans. METHODS We prospectively evaluated patients with non–MRI-conditional cardiac implantable electrical devices referred for MRI scans under a strict clinical protocol. The primary safety outcome was incidence of major adverse events (loss of pacing, inappropriate shock or antitachycardia pacing, need for system revision, or death) or minor adverse events (inappropriate pacing, arrhythmias, power-on-reset events, heating at the generator site, or changes in device parameters at baseline or at 6 months). RESULTS A total of 189 MRI scans were performed in 123 patients (63.1% [78] men; median age 70 ± 18.5 years; 37.0% [70] patients with implantable cardioverter-defibrillators; 21.8% [41] pacemaker-dependent patients) predominantly for brain or spinal conditions. A minority of scans (22.7% [43]) were performed for urgent or emergent indications. Major adverse events were rare: 1 patient with loss of pacing, no deaths, or system revisions (overall rate 0.5%; 95% confidence interval 0.01–2.91). Minor adverse events were similarly rare (overall rate 1.6%; 95% confidence interval 0.3–4.6). Nearly all studies (98.4% [186]) were interpretable, while 74.9% [142] were determined to change management according to the prespecified criteria. No clinically significant changes were observed in device parameters acutely after MRI or at 6 months as compared with baseline across all patient and device categories. CONCLUSION Off-label MRI scans performed under a strict protocol demonstrated excellent short- and medium-term safety while providing interpretable imaging that frequently influenced clinical care. PMID:28385671

Sparse magnetic resonance imaging reconstruction using the bregman iteration

NASA Astrophysics Data System (ADS)

Lee, Dong-Hoon; Hong, Cheol-Pyo; Lee, Man-Woo

2013-01-01

Magnetic resonance imaging (MRI) reconstruction needs many samples that are sequentially sampled by using phase encoding gradients in a MRI system. It is directly connected to the scan time for the MRI system and takes a long time. Therefore, many researchers have studied ways to reduce the scan time, especially, compressed sensing (CS), which is used for sparse images and reconstruction for fewer sampling datasets when the k-space is not fully sampled. Recently, an iterative technique based on the bregman method was developed for denoising. The bregman iteration method improves on total variation (TV) regularization by gradually recovering the fine-scale structures that are usually lost in TV regularization. In this study, we studied sparse sampling image reconstruction using the bregman iteration for a low-field MRI system to improve its temporal resolution and to validate its usefulness. The image was obtained with a 0.32 T MRI scanner (Magfinder II, SCIMEDIX, Korea) with a phantom and an in-vivo human brain in a head coil. We applied random k-space sampling, and we determined the sampling ratios by using half the fully sampled k-space. The bregman iteration was used to generate the final images based on the reduced data. We also calculated the root-mean-square-error (RMSE) values from error images that were obtained using various numbers of bregman iterations. Our reconstructed images using the bregman iteration for sparse sampling images showed good results compared with the original images. Moreover, the RMSE values showed that the sparse reconstructed phantom and the human images converged to the original images. We confirmed the feasibility of sparse sampling image reconstruction methods using the bregman iteration with a low-field MRI system and obtained good results. Although our results used half the sampling ratio, this method will be helpful in increasing the temporal resolution at low-field MRI systems.

Non-invasive imaging of transplanted human neural stem cells and ECM scaffold remodeling in the stroke-damaged rat brain by (19)F- and diffusion-MRI.

PubMed

Bible, Ellen; Dell'Acqua, Flavio; Solanky, Bhavana; Balducci, Anthony; Crapo, Peter M; Badylak, Stephen F; Ahrens, Eric T; Modo, Michel

2012-04-01

Transplantation of human neural stem cells (hNSCs) is emerging as a viable treatment for stroke related brain injury. However, intraparenchymal grafts do not regenerate lost tissue, but rather integrate into the host parenchyma without significantly affecting the lesion cavity. Providing a structural support for the delivered cells appears important for cell based therapeutic approaches. The non-invasive monitoring of therapeutic methods would provide valuable information regarding therapeutic strategies but remains a challenge. Labeling transplanted cells with metal-based (1)H-magnetic resonance imaging (MRI) contrast agents affects the visualization of the lesion cavity. Herein, we demonstrate that a (19)F-MRI contrast agent can adequately monitor the distribution of transplanted cells, whilst allowing an evaluation of the lesion cavity and the formation of new tissue on (1)H-MRI scans. Twenty percent of cells labeled with the (19)F agent were of host origin, potentially reflecting the re-uptake of label from dead transplanted cells. Both T(2)- and diffusion-weighted MRI scans indicated that transplantation of hNSCs suspended in a gel form of a xenogeneic extracellular matrix (ECM) bioscaffold resulted in uniformly distributed cells throughout the lesion cavity. However, diffusion MRI indicated that the injected materials did not yet establish diffusion barriers (i.e. cellular network, fiber tracts) normally found within striatal tissue. The ECM bioscaffold therefore provides an important support to hNSCs for the creation of de novo tissue and multi-nuclei MRI represents an adept method for the visualization of some aspects of this process. However, significant developments of both the transplantation paradigm, as well as regenerative imaging, are required to successfully create new tissue in the lesion cavity and to monitor this process non-invasively. Copyright © 2011 Elsevier Ltd. All rights reserved.

The costs and utility of imaging in evaluating dizzy patients in the emergency room.

PubMed

Ahsan, Syed F; Syamal, Mausumi N; Yaremchuk, Kathleen; Peterson, Edward; Seidman, Michael

2013-09-01

To determine the usefulness and the costs of computed tomography (CT) and magnetic resonance imaging (MRI) in the evaluation of patients with dizziness in the emergency department (ED). Retrospective chart review. Charts of patients with a specific health maintenance insurance plan presenting with dizziness and vertigo to a large health system's ED between January 2008 and January 2011 were reviewed. Patient demographics, signs/symptoms, and CT and MRI results were assessed. CT and MRI charges were determined based on positive versus unremarkable findings. Data analysis included stepwise logistic regressions. Of 1681 patients identified, 810 (48%) received CT brain/head scan totaling $988,200 in charges. Of these, only 0.74% yielded clinically significant pathology requiring intervention. However, 12.2% of MRI studies yielded discovery of significant abnormalities. Logistic regression analysis revealed that older patients (P = .001) were more likely to receive a CT scan. In the 3-year period studied, CT scans for ED patients with dizziness and vertigo yielded a low predictive value for significant pathology. These data reveal a great opportunity for cost savings by developing stricter guidelines for ordering CT scans for this set of ED patients. The use of MRI in all cases of dizziness was found to be neither practical nor useful. However, appropriately directed MRI of the brain is recommended in patients with dizziness and other neurological signs or symptoms. Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

The use of parallel imaging for MRI assessment of knees in children and adolescents.

PubMed

Doria, Andrea S; Chaudry, Gulraiz A; Nasui, Cristina; Rayner, Tammy; Wang, Chenghua; Moineddin, Rahim; Babyn, Paul S; White, Larry M; Sussman, Marshall S

2010-03-01

Parallel imaging provides faster scanning at the cost of reduced signal-to-noise ratio (SNR) and increased artifacts. To compare the diagnostic performance of two parallel MRI protocols (PPs) for assessment of pathologic knees using an 8-channel knee coil (reference standard, conventional protocol [CP]) and to characterize the SNR losses associated with parallel imaging. Two radiologists blindly interpreted 1.5 Tesla knee MRI images in 21 children (mean 13 years, range 9-18 years) with clinical indications for an MRI scan. Sagittal proton density, T2-W fat-saturated FSE, axial T2-W fat-saturated FSE, and coronal T1-W (NEX of 1,1,1) images were obtained with both CP and PP. Images were read for soft tissue and osteochondral findings. There was a 75% decrease in acquisition time using PP in comparison to CP. The CP and PP protocols fell within excellent or upper limits of substantial agreement: CP, kappa coefficient, 0.81 (95% CIs, 0.73-0.89); PP, 0.80-0.81 (0.73-0.89). The sensitivity of the two PPs was similar for assessment of soft (0.98-1.00) and osteochondral (0.89-0.94) tissues. Phantom data indicated an SNR of 1.67, 1.6, and 1.51 (axial, sagittal and coronal planes) between CP and PP scans. Parallel MRI provides a reliable assessment for pediatric knees in a significantly reduced scan time without affecting the diagnostic performance of MRI.

Radiological features for the approach in trans-sphenoidal pituitary surgery.

PubMed

Twigg, Victoria; Carr, Simon D; Balakumar, Ramkishan; Sinha, Saurabh; Mirza, Showkat

2017-08-01

In order to perform trans-sphenoidal endoscopic pituitary surgery safely and efficiently it is important to identify anatomical and pituitary disease features on the pre-operative CT and MRI scans; thereby minimising the risk to surrounding structures and optimising outcomes. We aim to create a checklist to streamline pre-operative planning. We retrospectively reviewed pre-operative CT and MRI scans of 100 adults undergoing trans-sphenoidal endoscopic pituitary surgery. Radiological findings and their incidence included deviated nasal septum (62%), concha bullosa (32%), bony dehiscence of the carotid arteries (18%), sphenoid septation overlying the internal carotid artery (24% at the sella) and low lying CSF (32%). The mean distance of the sphenoid ostium to the skull base was 10 mm (range 2.7-17.6 mm). We also describe the 'teddy bear' sign which when present on an axial CT indicates the carotid arteries will be identifiable intra-operatively. There are significant variations in the anatomical and pituitary disease features between patients. We describe a number of features on pre-operative scans and have devised a checklist including a new 'teddy bear' sign to aid the surgeon in the anatomical assessment of patients undergoing trans-sphenoidal pituitary surgery.

Whole-body MRI assessment of disease activity and structural damage in rheumatoid arthritis: first step towards an MRI joint count.

PubMed

Axelsen, Mette Bjørndal; Eshed, Iris; Duer-Jensen, Anne; Møller, Jakob M; Pedersen, Susanne Juhl; Østergaard, Mikkel

2014-05-01

The aim of this study was to investigate the ability of whole-body MRI (WBMRI) to visualize inflammation [synovitis, bone marrow oedema (BME) and enthesitis] and structural damage in patients with RA. The 3T WBMR images were acquired in a head-to-toe scan in 20 patients with RA and at least one swollen or tender joint. Short Tau Inversion Recovery and pre- and post-contrast T1-weighted images were evaluated for readability and the presence/absence of inflammation (synovitis, BME and enthesitis) and structural damage (erosions and fat infiltrations) in 76 peripheral joints, 30 entheseal sites and in the spine. The readability was >70% for all individual joints, except for the most peripheral joints of the hands and feet. Synovitis was most frequent in the wrist, first tarsometatarsal, first CMC joints and glenohumeral joints (67-61%); BME in the wrist, CMC, acromioclavicular and glenohumeral joints (45-35%) and erosions in the wrist, MTP and CMC joints (19-16%). Enthesitis at ≥ 1 site was registered in 16 patients. BME was frequently seen in the cervical (20%) but not the thoracic and lumbar spine, while fat infiltrations and erosions were rare. The intrareader agreement was high (85-100%) for all pathologies. The agreement between WBMRI and clinical findings was low. Peripheral and axial inflammation and structural damage at joints and entheses was frequently identified by WBMRI, and more frequently than by clinical examination. WBMRI is a promising tool for evaluation of the total inflammatory load of inflammation (an MRI joint count) and structural damage in RA patients.

The sequential structure of brain activation predicts skill.

PubMed

Anderson, John R; Bothell, Daniel; Fincham, Jon M; Moon, Jungaa

2016-01-29

In an fMRI study, participants were trained to play a complex video game. They were scanned early and then again after substantial practice. While better players showed greater activation in one region (right dorsal striatum) their relative skill was better diagnosed by considering the sequential structure of whole brain activation. Using a cognitive model that played this game, we extracted a characterization of the mental states that are involved in playing a game and the statistical structure of the transitions among these states. There was a strong correspondence between this measure of sequential structure and the skill of different players. Using multi-voxel pattern analysis, it was possible to recognize, with relatively high accuracy, the cognitive states participants were in during particular scans. We used the sequential structure of these activation-recognized states to predict the skill of individual players. These findings indicate that important features about information-processing strategies can be identified from a model-based analysis of the sequential structure of brain activation. Copyright © 2015 Elsevier Ltd. All rights reserved.

3D ECG- and respiratory-gated non-contrast-enhanced (CE) perfusion MRI for postoperative lung function prediction in non-small-cell lung cancer patients: A comparison with thin-section quantitative computed tomography, dynamic CE-perfusion MRI, and perfusion scan.

PubMed

Ohno, Yoshiharu; Seki, Shinichiro; Koyama, Hisanobu; Yoshikawa, Takeshi; Matsumoto, Sumiaki; Takenaka, Daisuke; Kassai, Yoshimori; Yui, Masao; Sugimura, Kazuro

2015-08-01

To compare predictive capabilities of non-contrast-enhanced (CE)- and dynamic CE-perfusion MRIs, thin-section multidetector computed tomography (CT) (MDCT), and perfusion scan for postoperative lung function in non-small cell lung cancer (NSCLC) patients. Sixty consecutive pathologically diagnosed NSCLC patients were included and prospectively underwent thin-section MDCT, non-CE-, and dynamic CE-perfusion MRIs and perfusion scan, and had their pre- and postoperative forced expiratory volume in one second (FEV1 ) measured. Postoperative percent FEV1 (po%FEV1 ) was then predicted from the fractional lung volume determined on semiquantitatively assessed non-CE- and dynamic CE-perfusion MRIs, from the functional lung volumes determined on quantitative CT, from the number of segments observed on qualitative CT, and from uptakes detected on perfusion scans within total and resected lungs. Predicted po%FEV1 s were then correlated with actual po%FEV1 s, which were %FEV1 s measured postoperatively. The limits of agreement were also determined. All predicted po%FEV1 s showed significant correlation (0.73 ≤ r ≤ 0.93, P < 0.0001) and limits of agreement with actual po%FEV1 (non-CE-perfusion MRI: 0.3 ± 10.0%, dynamic CE-perfusion MRI: 1.0 ± 10.8%, perfusion scan: 2.2 ± 14.1%, quantitative CT: 1.2 ± 9.0%, qualitative CT: 1.5 ± 10.2%). Non-CE-perfusion MRI may be able to predict postoperative lung function more accurately than qualitatively assessed MDCT and perfusion scan. © 2014 Wiley Periodicals, Inc.

Renal damages after extracorporeal shock wave lithotripsy evaluated by Gd-DTPA-enhanced dynamic magnetic resonance imaging.

PubMed

Umekawa, T; Kohri, K; Yamate, T; Amasaki, N; Ishikawa, Y; Takada, M; Iguchi, M; Kurita, T

1992-01-01

Renal damages after extracorporeal shock wave lithotripsy (ESWL) were evaluated by magnetic resonance imaging (MRI) including Gd-DTPA-enhanced dynamic MRI in 37 patients with renal stone by spin echo methods (T1 and T2-weighted scan) and small tip angle gradient echo method (T2-weighted scan). Sixty-eight percent of the patients had changes in the MRI findings after ESWL. The frequently observed findings were perirenal fluid collection (38%), loss of corticomedullary junction (35%), and increased signal intensity of muscle and other adjacent tissue (34%). Preoperative Gd-DTPA-enhanced dynamic MRI showed low intensity band which suggests Gd-DTPA secretion from the glomerulus into the renal tubulus. In all cases the low intensity band became unclear after ESWL because of renal contusion due to ESWL. MRI, including Gd-DTPA-enhanced dynamic MRI, is considered to be a good procedure for evaluation of renal damages due to ESWL.

CAVIAR: CLASSIFICATION VIA AGGREGATED REGRESSION AND ITS APPLICATION IN CLASSIFYING OASIS BRAIN DATABASE

PubMed Central

Chen, Ting; Rangarajan, Anand; Vemuri, Baba C.

2010-01-01

This paper presents a novel classification via aggregated regression algorithm – dubbed CAVIAR – and its application to the OASIS MRI brain image database. The CAVIAR algorithm simultaneously combines a set of weak learners based on the assumption that the weight combination for the final strong hypothesis in CAVIAR depends on both the weak learners and the training data. A regularization scheme using the nearest neighbor method is imposed in the testing stage to avoid overfitting. A closed form solution to the cost function is derived for this algorithm. We use a novel feature – the histogram of the deformation field between the MRI brain scan and the atlas which captures the structural changes in the scan with respect to the atlas brain – and this allows us to automatically discriminate between various classes within OASIS [1] using CAVIAR. We empirically show that CAVIAR significantly increases the performance of the weak classifiers by showcasing the performance of our technique on OASIS. PMID:21151847

CAVIAR: CLASSIFICATION VIA AGGREGATED REGRESSION AND ITS APPLICATION IN CLASSIFYING OASIS BRAIN DATABASE.

PubMed

Chen, Ting; Rangarajan, Anand; Vemuri, Baba C

2010-04-14

This paper presents a novel classification via aggregated regression algorithm - dubbed CAVIAR - and its application to the OASIS MRI brain image database. The CAVIAR algorithm simultaneously combines a set of weak learners based on the assumption that the weight combination for the final strong hypothesis in CAVIAR depends on both the weak learners and the training data. A regularization scheme using the nearest neighbor method is imposed in the testing stage to avoid overfitting. A closed form solution to the cost function is derived for this algorithm. We use a novel feature - the histogram of the deformation field between the MRI brain scan and the atlas which captures the structural changes in the scan with respect to the atlas brain - and this allows us to automatically discriminate between various classes within OASIS [1] using CAVIAR. We empirically show that CAVIAR significantly increases the performance of the weak classifiers by showcasing the performance of our technique on OASIS.

SU-E-J-220: Assessment of MRI Geometric Distortion in Head and Neck Cancer Patients Scanned in Immobilized Radiation Treatment Position

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, C; Mohamed, A; Weygand, J

2015-06-15

Purpose: Uncertainties about geometric distortion have somewhat hindered MRI simulation in radiation therapy. Most of the geometric distortion studies were performed with phantom measurements but another major aspect of MR distortion is patient related. We studied the geometric distortion in patient images by comparing their MRI scans with the corresponding CT, using CT as the non-distorted gold standard. Methods: Ten H&N cancer patients were imaged with MRI as part of a prospective IRB approved study. All patients had their treatment planning CT done on the same day or within one week of the MRI. MR Images were acquired with amore » T2 SE sequence (1×1×2.5mm voxel size) in the same immobilization position as in the CT scans. MRI to CT rigid registration was then done and geometric distortion comparison was done by measuring the corresponding anatomical landmarks on both the MRI and the CT images by two observers. Several skin to skin (9 landmarks), bone to bone (8 landmarks), and soft tissue (3 landmarks) were measured at specific levels in horizontal and vertical planes of both scans. Results: The mean distortion for all landmark measurements in all scans was 1.8±1.9mm. For each patient 11 measurements were done in the horizontal plane while 9 were done in the vertical plane. The measured geometric distortion were significantly lower in the horizontal axis compared to the vertical axis (1.3±0.16 mm vs 2.2±0.19 mm, respectively, P=0.003*). The magnitude of distortion was lower in the bone to bone landmarks compared to the combined soft tissue and skin to skin landmarks (1.2±0.19 mm vs 2.3±0.17 mm, P=0.0006*). The mean distortion measured by observer one was not significantly different compared toobserver 2 (2.3 vs 2.4 mm, P=0.4). Conclusion: MRI geometric distortions were quantified in H&N patients with mean error of less than 2 mm. JW received a corporate sponsored research grant from Elekta.« less

Validation of automated white matter hyperintensity segmentation.

PubMed

Smart, Sean D; Firbank, Michael J; O'Brien, John T

2011-01-01

Introduction. White matter hyperintensities (WMHs) are a common finding on MRI scans of older people and are associated with vascular disease. We compared 3 methods for automatically segmenting WMHs from MRI scans. Method. An operator manually segmented WMHs on MRI images from a 3T scanner. The scans were also segmented in a fully automated fashion by three different programmes. The voxel overlap between manual and automated segmentation was compared. Results. Between observer overlap ratio was 63%. Using our previously described in-house software, we had overlap of 62.2%. We investigated the use of a modified version of SPM segmentation; however, this was not successful, with only 14% overlap. Discussion. Using our previously reported software, we demonstrated good segmentation of WMHs in a fully automated fashion.

Time-delayed contrast-enhanced MRI improves detection of brain metastases and apparent treatment volumes.

PubMed

Kushnirsky, Marina; Nguyen, Vinh; Katz, Joel S; Steinklein, Jared; Rosen, Lisa; Warshall, Craig; Schulder, Michael; Knisely, Jonathan P S

2016-02-01

Contrast-enhanced MRI is the preeminent diagnostic test for brain metastasis (BM). Detection of BMs for stereotactic radiosurgery (SRS) planning may improve with a time delay following administration of a high-relaxivity agent for 1.5-T and 3-T imaging systems. Metastasis detection with time-delayed MRI was evaluated in this study. Fifty-three volumetric MRI studies from 38 patients undergoing SRS for BMs were evaluated. All studies used 0.1-mmol/kg gadobenate dimeglumine (MultiHance; Bracco Diagnostics) immediately after injection, followed by 2 more axial T1-weighted sequences after 5-minute intervals (final image acquisition commenced 15 minutes after contrast injection). Two studies were motion limited and excluded. Two hundred eighty-seven BMs were identified. The studies were randomized and examined separately by 3 radiologists, who were blinded to the temporal sequence. Each radiologist recorded the number of BMs detected per scan. A Wilcoxon signed-rank test compared BM numbers between scans. One radiologist determined the scan on which BMs were best defined. All confirmed, visible tumors were contoured using iPlan RT treatment planning software on each of the 3 MRI data sets. A linear mixed model was used to analyze volume changes. The interclass correlations for Scans 1, 2, and 3 were 0.7392, 0.7951, and 0.7290, respectively, demonstrating excellent interrater reliability. At least 1 new lesion was detected in the second scan as compared with the first in 35.3% of subjects (95% CI 22.4%-49.9%). The increase in BM numbers between Scans 1 and 2 ranged from 1 to 10. At least 1 new lesion was detected in the third scan as compared with the second in 21.6% of subjects (95% CI 11.3%-35.3%). The increase in BM numbers between Scans 2 and 3 ranged from 1 to 9. Between Scans 1 and 3, additional tumors were seen on 43.1% of scans (increase ranged from 1 to 14). The median increase in tumor number for all comparisons was 1. There was a significant increase in number of BMs detected from Scan 1 to Scan 2 (p < 0.0367) and from Scan 1 to Scan 3 (p < 0.0264). In 34 of the 51 subjects (66.7%), the radiologist selected the third scan as the one providing the clearest tumor definition. There was an average 25.4% increase in BM volume between Scans 1 and 2 (p < 0.0001) and a 9% increase in BM volume between Scans 2 and 3 (p = 0.0001). In patients who are being prepared for SRS of BMs, delayed MRI after contrast injection revealed more targets that needed treatment. In addition, apparent treatment volumes increased with a time delay. To avoid missing tumors that could be treated at the time of planned SRS and resultant "treatment failures," the authors recommend that postcontrast MR images be acquired between 10 and 15 minutes after injection in patients undergoing SRS for treatment of BMs.

Anticipatory stress associated with functional magnetic resonance imaging: Implications for psychosocial stress research.

PubMed

Gossett, Ethan W; Wheelock, Muriah D; Goodman, Adam M; Orem, Tyler R; Harnett, Nathaniel G; Wood, Kimberly H; Mrug, Sylvie; Granger, Douglas A; Knight, David C

2018-03-01

Stress tasks performed during functional magnetic resonance imaging (fMRI) elicit a relatively small cortisol response compared to stress tasks completed in a traditional behavioral laboratory, which may be due to apprehension of fMRI that elicits an anticipatory stress response. The present study investigated whether anticipatory stress is greater prior to research completed in an MRI environment than in a traditional behavioral laboratory. Anticipatory stress (indexed by cortisol) was greater prior to testing in the MRI environment than traditional behavioral laboratory. Furthermore, anticipation of fMRI elicited a cortisol response commensurate with the response to the stress task in the behavioral laboratory. However, in the MRI environment, post-stress cortisol was significantly lower than baseline cortisol. Taken together, these findings suggest the stress elicited by anticipation of fMRI may lead to acute elevations in cortisol prior to scanning, which may in turn disrupt the cortisol response to stress tasks performed during scanning. Copyright © 2018 Elsevier B.V. All rights reserved.

A wearable bluetooth LE sensor for patient monitoring during MRI scans.

PubMed

Vogt, Christian; Reber, Jonas; Waltisberg, Daniel; Buthe, Lars; Marjanovic, Josip; Munzenrieder, Niko; Pruessmann, Klaas P; Troster, Gerhard

2016-08-01

This paper presents a working prototype of a wearable patient monitoring device capable of recording the heart rate, blood oxygen saturation, surface temperature and humidity during an magnetic resonance imaging (MRI) experiment. The measured values are transmitted via Bluetooth low energy (LE) and displayed in real time on a smartphone on the outside of the MRI room. During 7 MRI image acquisitions of at least 1 min and a total duration of 25 min no Bluetooth data packets were lost. The raw measurements of the light intensity for the photoplethysmogram based heart rate measurement shows an increased noise floor by 50LSB (least significant bit) during the MRI operation, whereas the temperature and humidity readings are unaffected. The device itself creates a magnetic resonance (MR) signal loss with a radius of 14 mm around the device surface and shows no significant increase in image noise of an acquired MRI image due to its radio frequency activity. This enables continuous and unobtrusive patient monitoring during MRI scans.

Optimal gadolinium dose level for magnetic resonance imaging (MRI) contrast enhancement of U87-derived tumors in athymic nude rats for the assessment of photodynamic therapy

NASA Astrophysics Data System (ADS)

Cross, Nathan; Varghai, Davood; Flask, Chris A.; Feyes, Denise K.; Oleinick, Nancy L.; Dean, David

2009-02-01

This study aims to determine the effect of varying gadopentetate dimeglumine (Gd-DTPA) dose on Dynamic Contrast Enhanced-Magnetic Resonance Imaging (DCE-MRI) tracking of brain tumor photodynamic therapy (PDT) outcome. Methods: We injected 2.5 x 105 U87 cells (derived from human malignant glioma) into the brains of six athymic nude rats. After 9, 12, and 13 days DCE-MRI images were acquired on a 9.4 T micro-MRI scanner before and after administration of 100, 150, or 200 μL of Gd-DTPA. Results: Tumor region normalized DCE-MRI scan enhancement at peak was: 1.217 over baseline (0.018 Standard Error [SE]) at the 100 μL dose, 1.339 (0.013 SE) at the 150 μL dose, and 1.287 (0.014 SE) at the 200 μL dose. DCE-MRI peak tumor enhancement at the 150 μL dose was significantly greater than both the 100 μL dose (p < 3.323E-08) and 200 μL dose (p < 0.0007396). Discussion: In this preliminary study, the 150 μL Gd-DTPA dose provided the greatest T1 weighted contrast enhancement, while minimizing negative T2* effects, in DCE-MRI scans of U87-derived tumors. Maximizing Gd-DTPA enhancement in DCE-MRI scans may assist development of a clinically robust (i.e., unambiguous) technique for PDT outcome assessment.

Functional Magnetic Resonance Imaging for Preoperative Planning in Brain Tumour Surgery.

PubMed

Lau, Jonathan C; Kosteniuk, Suzanne E; Bihari, Frank; Megyesi, Joseph F

2017-01-01

Functional magnetic resonance imaging (fMRI) is being increasingly used for the preoperative evaluation of patients with brain tumours. The study is a retrospective chart review investigating the use of clinical fMRI from 2002 through 2013 in the preoperative evaluation of brain tumour patients. Baseline demographic and clinical data were collected. The specific fMRI protocols used for each patient were recorded. Sixty patients were identified over the 12-year period. The tumour types most commonly investigated were high-grade glioma (World Health Organization grade III or IV), low-grade glioma (World Health Organization grade II), and meningioma. Most common presenting symptoms were seizures (69.6%), language deficits (23.2%), and headache (19.6%). There was a predominance of left hemispheric lesions investigated with fMRI (76.8% vs 23.2% for right). The most commonly involved lobes were frontal (64.3%), temporal (33.9%), parietal (21.4%), and insular (7.1%). The most common fMRI paradigms were language (83.9%), motor (75.0%), sensory (16.1%), and memory (10.7%). The majority of patients ultimately underwent a craniotomy (75.0%), whereas smaller groups underwent stereotactic biopsy (8.9%) and nonsurgical management (16.1%). Time from request for fMRI to actual fMRI acquisition was 3.1±2.3 weeks. Time from fMRI acquisition to intervention was 4.9±5.5 weeks. We have characterized patient demographics in a retrospective single-surgeon cohort undergoing preoperative clinical fMRI at a Canadian centre. Our experience suggests an acceptable wait time from scan request to scan completion/analysis and from scan to intervention.

Planning magnetic resonance imaging for prostate cancer intensity-modulated radiation therapy: Impact on target volumes, radiotherapy dose and androgen deprivation administration.

PubMed

Horsley, Patrick J; Aherne, Noel J; Edwards, Grace V; Benjamin, Linus C; Wilcox, Shea W; McLachlan, Craig S; Assareh, Hassan; Welshman, Richard; McKay, Michael J; Shakespeare, Thomas P

2015-03-01

Magnetic resonance imaging (MRI) scans are increasingly utilized for radiotherapy planning to contour the primary tumors of patients undergoing intensity-modulated radiation therapy (IMRT). These scans may also demonstrate cancer extent and may affect the treatment plan. We assessed the impact of planning MRI detection of extracapsular extension, seminal vesicle invasion, or adjacent organ invasion on the staging, target volume delineation, doses, and hormonal therapy of patients with prostate cancer undergoing IMRT. The records of 509 consecutive patients with planning MRI scans being treated with IMRT for prostate cancer between January 2010 and July 2012 were retrospectively reviewed. Tumor staging and treatment plans before and after MRI were compared. Of the 509 patients, 103 (20%) were upstaged and 44 (9%) were migrated to a higher risk category as a result of findings at MRI. In 94 of 509 patients (18%), the MRI findings altered management. Ninety-four of 509 patients (18%) had a change to their clinical target volume (CTV) or treatment technique, and in 41 of 509 patients (8%) the duration of hormone therapy was changed because of MRI findings. The use of radiotherapy planning MRI altered CTV design, dose and/or duration of androgen deprivation in 18% of patients in this large, single institution series of men planned for dose-escalated prostate IMRT. This has substantial implications for radiotherapy target volumes and doses, as well as duration of androgen deprivation. Further research is required to investigate whether newer MRI techniques can simultaneously fulfill staging and radiotherapy contouring roles. © 2014 Wiley Publishing Asia Pty Ltd.

The Value of Restaging With Chest and Abdominal CT/MRI Scan After Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer.

PubMed

Liu, Guo-Chen; Zhang, Xu; Xie, E; An, Xin; Cai, Pei-Qiang; Zhu, Ying; Tang, Jing-Hua; Kong, Ling-Heng; Lin, Jun-Zhong; Pan, Zhi-Zhong; Ding, Pei-Rong

2015-11-01

Little was known with regard to the value of preoperative systemic restaging for patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (CRT). This study was designed to evaluate the role of chest and abdominal computed tomography (CT) scan or magnetic resonance imaging (MRI) on preoperative restaging in LARC after neoadjuvant CRT and to assess the impact on treatment strategy.Between January 2007 and April 2013, 386 newly diagnosed consecutive patients with LARC who underwent neoadjuvant CRT and received restaging with chest and abdominal CT/MRI scan were included. Imaging results before and after CRT were analyzed.Twelve patients (3.1%) (6 liver lesions, 2 peritoneal lesions, 2 distant lymph node lesions, 1 lung lesions, 1 liver and lung lesions) were diagnosed as suspicious metastases on the restaging scan after radiotherapy. Seven patients (1.8%) were confirmed as metastases by pathology or long-term follow-up. The treatment strategy was changed in 5 of the 12 patients as a result of restaging CT/MRI findings. Another 10 patients (2.6%) who present with normal restaging imaging findings were diagnosed as metastases intra-operatively. The sensitivity, specificity accuracy, negative predictive value, and positive predictive values of restaging CT/MRI was 41.4%, 98.6%, 58.3%, and 97.3%, respectively.The low incidence of metastases and minimal consequences for the treatment plan question the clinical value of routine restaging of chest and abdomen after neoadjuvant CRT. Based on this study, a routine restaging CT/MRI of chest and abdomen in patients with rectal cancer after neoadjuvant CRT is not advocated, carcino-embryonic antigen (CEA) -guided CT/MRI restaging might be an alternative.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brezovich, I; Wu, X; Popple, R

Purpose: To test spatial and dosimetric accuracy of small cranial target irradiation based on 1.5 T MRI scans using static arcs with MLC-defined fields Methods: A plastic (PMMA) phantom simulating a small brain lesion was mounted on a GammaKnife headframe equipped with MRI localizer. The lesion was a 3 mm long, 3.175 mm diameter cylindrical cavity filled with MRI contrast. Radiochromic film passing through the cavity was marked with pin pricks at the cavity center. The cavity was contoured on an MRI image and fused with CT to simulate treatment of a lesion not visible on CT. The transfer ofmore » the target to CT involved registering the MRI contrast cannels of the localizer that were visible on both modalities. Treatments were planned to deliver 800 cGy to the cavity center using multiple static arcs with 5.0×2.4 mm MLC-defined fields. The phantom was aligned on a STx accelerator by registering the conebeam CT with the planning CT. Films from coronal and sagittal planes were scanned and evaluated using ImageJ software Results: Geographic errors in treatment based on 1.5 T scans agreed within 0.33, −0.27 and 1.21 mm in the vertical, lateral and longitudinal dimensions, respectively. The doses delivered to the cavity center were 7.2% higher than planned. The dose distributions were similar to those of a GammaKnife. Conclusion: Radiation can be delivered with an accelerator at mm accuracy to small cranial targets based on 1.5 MRI scans fused to CTs using a standard GammaKnife headframe and MRI localizer. MLC-defined static arcs produce isodose lines very similar to the GammaKnife.« less

PET attenuation correction for flexible MRI surface coils in hybrid PET/MRI using a 3D depth camera

NASA Astrophysics Data System (ADS)

Frohwein, Lynn J.; Heß, Mirco; Schlicher, Dominik; Bolwin, Konstantin; Büther, Florian; Jiang, Xiaoyi; Schäfers, Klaus P.

2018-01-01

PET attenuation correction for flexible MRI radio frequency surface coils in hybrid PET/MRI is still a challenging task, as position and shape of these coils conform to large inter-patient variabilities. The purpose of this feasibility study is to develop a novel method for the incorporation of attenuation information about flexible surface coils in PET reconstruction using the Microsoft Kinect V2 depth camera. The depth information is used to determine a dense point cloud of the coil’s surface representing the shape of the coil. From a CT template—acquired once in advance—surface information of the coil is extracted likewise and converted into a point cloud. The two point clouds are then registered using a combination of an iterative-closest-point (ICP) method and a partially rigid registration step. Using the transformation derived through the point clouds, the CT template is warped and thereby adapted to the PET/MRI scan setup. The transformed CT template is converted into an attenuation map from Hounsfield units into linear attenuation coefficients. The resulting fitted attenuation map is then integrated into the MRI-based patient-specific DIXON-based attenuation map of the actual PET/MRI scan. A reconstruction of phantom PET data acquired with the coil present in the field-of-view (FoV), but without the corresponding coil attenuation map, shows large artifacts in regions close to the coil. The overall count loss is determined to be around 13% compared to a PET scan without the coil present in the FoV. A reconstruction using the new μ-map resulted in strongly reduced artifacts as well as increased overall PET intensities with a remaining relative difference of about 1% to a PET scan without the coil in the FoV.

Dislocation of cochlear implant magnet as a complication following MRI.

PubMed

Murtojärvi, Sarita; Salonen, Jaakko

According to current best knowledge, an MRI scan can be performed for patients with cochlear implants. The warnings and recommendations of the implant manufacturers must be followed strictly to prevent complications, such as overheating, migration or demagnetization of the magnet in the implant. We report on a case of cochlear implant magnet dislocation as a complication for an MRI scan. The patient had a tight bandage around the head to hold the magnet in place as recommended by the manufacturer, but apparently the bandage was not in the correct place.

Super-resolution reconstruction in frequency, image, and wavelet domains to reduce through-plane partial voluming in MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gholipour, Ali, E-mail: ali.gholipour@childrens.harvard.edu; Afacan, Onur; Scherrer, Benoit

Purpose: To compare and evaluate the use of super-resolution reconstruction (SRR), in frequency, image, and wavelet domains, to reduce through-plane partial voluming effects in magnetic resonance imaging. Methods: The reconstruction of an isotropic high-resolution image from multiple thick-slice scans has been investigated through techniques in frequency, image, and wavelet domains. Experiments were carried out with thick-slice T2-weighted fast spin echo sequence on the Academic College of Radiology MRI phantom, where the reconstructed images were compared to a reference high-resolution scan using peak signal-to-noise ratio (PSNR), structural similarity image metric (SSIM), mutual information (MI), and the mean absolute error (MAE) ofmore » image intensity profiles. The application of super-resolution reconstruction was then examined in retrospective processing of clinical neuroimages of ten pediatric patients with tuberous sclerosis complex (TSC) to reduce through-plane partial voluming for improved 3D delineation and visualization of thin radial bands of white matter abnormalities. Results: Quantitative evaluation results show improvements in all evaluation metrics through super-resolution reconstruction in the frequency, image, and wavelet domains, with the highest values obtained from SRR in the image domain. The metric values for image-domain SRR versus the original axial, coronal, and sagittal images were PSNR = 32.26 vs 32.22, 32.16, 30.65; SSIM = 0.931 vs 0.922, 0.924, 0.918; MI = 0.871 vs 0.842, 0.844, 0.831; and MAE = 5.38 vs 7.34, 7.06, 6.19. All similarity metrics showed high correlations with expert ranking of image resolution with MI showing the highest correlation at 0.943. Qualitative assessment of the neuroimages of ten TSC patients through in-plane and out-of-plane visualization of structures showed the extent of partial voluming effect in a real clinical scenario and its reduction using SRR. Blinded expert evaluation of image resolution in resampled out-of-plane views consistently showed the superiority of SRR compared to original axial and coronal image acquisitions. Conclusions: Thick-slice 2D T2-weighted MRI scans are part of many routine clinical protocols due to their high signal-to-noise ratio, but are often severely affected by through-plane partial voluming effects. This study shows that while radiologic assessment is performed in 2D on thick-slice scans, super-resolution MRI reconstruction techniques can be used to fuse those scans to generate a high-resolution image with reduced partial voluming for improved postacquisition processing. Qualitative and quantitative evaluation showed the efficacy of all SRR techniques with the best results obtained from SRR in the image domain. The limitations of SRR techniques are uncertainties in modeling the slice profile, density compensation, quantization in resampling, and uncompensated motion between scans.« less

Super-resolution reconstruction in frequency, image, and wavelet domains to reduce through-plane partial voluming in MRI

PubMed Central

Gholipour, Ali; Afacan, Onur; Aganj, Iman; Scherrer, Benoit; Prabhu, Sanjay P.; Sahin, Mustafa; Warfield, Simon K.

2015-01-01

Purpose: To compare and evaluate the use of super-resolution reconstruction (SRR), in frequency, image, and wavelet domains, to reduce through-plane partial voluming effects in magnetic resonance imaging. Methods: The reconstruction of an isotropic high-resolution image from multiple thick-slice scans has been investigated through techniques in frequency, image, and wavelet domains. Experiments were carried out with thick-slice T2-weighted fast spin echo sequence on the Academic College of Radiology MRI phantom, where the reconstructed images were compared to a reference high-resolution scan using peak signal-to-noise ratio (PSNR), structural similarity image metric (SSIM), mutual information (MI), and the mean absolute error (MAE) of image intensity profiles. The application of super-resolution reconstruction was then examined in retrospective processing of clinical neuroimages of ten pediatric patients with tuberous sclerosis complex (TSC) to reduce through-plane partial voluming for improved 3D delineation and visualization of thin radial bands of white matter abnormalities. Results: Quantitative evaluation results show improvements in all evaluation metrics through super-resolution reconstruction in the frequency, image, and wavelet domains, with the highest values obtained from SRR in the image domain. The metric values for image-domain SRR versus the original axial, coronal, and sagittal images were PSNR = 32.26 vs 32.22, 32.16, 30.65; SSIM = 0.931 vs 0.922, 0.924, 0.918; MI = 0.871 vs 0.842, 0.844, 0.831; and MAE = 5.38 vs 7.34, 7.06, 6.19. All similarity metrics showed high correlations with expert ranking of image resolution with MI showing the highest correlation at 0.943. Qualitative assessment of the neuroimages of ten TSC patients through in-plane and out-of-plane visualization of structures showed the extent of partial voluming effect in a real clinical scenario and its reduction using SRR. Blinded expert evaluation of image resolution in resampled out-of-plane views consistently showed the superiority of SRR compared to original axial and coronal image acquisitions. Conclusions: Thick-slice 2D T2-weighted MRI scans are part of many routine clinical protocols due to their high signal-to-noise ratio, but are often severely affected by through-plane partial voluming effects. This study shows that while radiologic assessment is performed in 2D on thick-slice scans, super-resolution MRI reconstruction techniques can be used to fuse those scans to generate a high-resolution image with reduced partial voluming for improved postacquisition processing. Qualitative and quantitative evaluation showed the efficacy of all SRR techniques with the best results obtained from SRR in the image domain. The limitations of SRR techniques are uncertainties in modeling the slice profile, density compensation, quantization in resampling, and uncompensated motion between scans. PMID:26632048

Magnetic resonance imaging for precise radiotherapy of small laboratory animals.

PubMed

Frenzel, Thorsten; Kaul, Michael Gerhard; Ernst, Thomas Michael; Salamon, Johannes; Jäckel, Maria; Schumacher, Udo; Krüll, Andreas

2017-03-01

Radiotherapy of small laboratory animals (SLA) is often not as precisely applied as in humans. Here we describe the use of a dedicated SLA magnetic resonance imaging (MRI) scanner for precise tumor volumetry, radiotherapy treatment planning, and diagnostic imaging in order to make the experiments more accurate. Different human cancer cells were injected at the lower trunk of pfp/rag2 and SCID mice to allow for local tumor growth. Data from cross sectional MRI scans were transferred to a clinical treatment planning system (TPS) for humans. Manual palpation of the tumor size was compared with calculated tumor size of the TPS and with tumor weight at necropsy. As a feasibility study MRI based treatment plans were calculated for a clinical 6MV linear accelerator using a micro multileaf collimator (μMLC). In addition, diagnostic MRI scans were used to investigate animals which did clinical poorly during the study. MRI is superior in precise tumor volume definition whereas manual palpation underestimates their size. Cross sectional MRI allow for treatment planning so that conformal irradiation of mice with a clinical linear accelerator using a μMLC is in principle feasible. Several internal pathologies were detected during the experiment using the dedicated scanner. MRI is a key technology for precise radiotherapy of SLA. The scanning protocols provided are suited for tumor volumetry, treatment planning, and diagnostic imaging. Copyright © 2016. Published by Elsevier GmbH.

Advanced morphological and biochemical magnetic resonance imaging of cartilage repair procedures in the knee joint at 3 Tesla.

PubMed

Welsch, Goetz H; Mamisch, Tallal C; Hughes, Timothy; Domayer, Stephan; Marlovits, Stefan; Trattnig, Siegfried

2008-09-01

Morphological and biochemical magnetic resonance imaging (MRI) is due to high field MR systems, advanced coil technology, and sophisticated sequence protocols capable of visualizing articular cartilage in vivo with high resolution in clinical applicable scan time. Several conventional two-dimensional (2D) and three-dimensional (3D) approaches show changes in cartilage structure. Furthermore newer isotropic 3D sequences show great promise in improving cartilage imaging and additionally in diagnosing surrounding pathologies within the knee joint. Functional MR approaches are additionally able to provide a specific measure of the composition of cartilage. Cartilage physiology and ultra-structure can be determined, changes in cartilage macromolecules can be detected, and cartilage repair tissue can thus be assessed and potentially differentiated. In cartilage defects and following nonsurgical and surgical cartilage repair, morphological MRI provides the basis for diagnosis and follow-up evaluation, whereas biochemical MRI provides a deeper insight into the composition of cartilage and cartilage repair tissue. A combination of both, together with clinical evaluation, may represent a desirable multimodal approach in the future, also available in routine clinical use.

The heritability of the functional connectome is robust to common nonlinear registration methods

NASA Astrophysics Data System (ADS)

Hafzalla, George W.; Prasad, Gautam; Baboyan, Vatche G.; Faskowitz, Joshua; Jahanshad, Neda; McMahon, Katie L.; de Zubicaray, Greig I.; Wright, Margaret J.; Braskie, Meredith N.; Thompson, Paul M.

2016-03-01

Nonlinear registration algorithms are routinely used in brain imaging, to align data for inter-subject and group comparisons, and for voxelwise statistical analyses. To understand how the choice of registration method affects maps of functional brain connectivity in a sample of 611 twins, we evaluated three popular nonlinear registration methods: Advanced Normalization Tools (ANTs), Automatic Registration Toolbox (ART), and FMRIB's Nonlinear Image Registration Tool (FNIRT). Using both structural and functional MRI, we used each of the three methods to align the MNI152 brain template, and 80 regions of interest (ROIs), to each subject's T1-weighted (T1w) anatomical image. We then transformed each subject's ROIs onto the associated resting state functional MRI (rs-fMRI) scans and computed a connectivity network or functional connectome for each subject. Given the different degrees of genetic similarity between pairs of monozygotic (MZ) and same-sex dizygotic (DZ) twins, we used structural equation modeling to estimate the additive genetic influences on the elements of the function networks, or their heritability. The functional connectome and derived statistics were relatively robust to nonlinear registration effects.

Living With Anxiety Disorders, Worried Sick | NIH MedlinePlus the Magazine

MedlinePlus

... behaviors. Using an imaging technique called functional MRI (fMRI), scientists are scanning the brain in action as ... Bishop of the University of California, Berkeley, uses fMRI to study people at high risk for anxiety ...

3D variational brain tumor segmentation on a clustered feature set

NASA Astrophysics Data System (ADS)

Popuri, Karteek; Cobzas, Dana; Jagersand, Martin; Shah, Sirish L.; Murtha, Albert

2009-02-01

Tumor segmentation from MRI data is a particularly challenging and time consuming task. Tumors have a large diversity in shape and appearance with intensities overlapping the normal brain tissues. In addition, an expanding tumor can also deflect and deform nearby tissue. Our work addresses these last two difficult problems. We use the available MRI modalities (T1, T1c, T2) and their texture characteristics to construct a multi-dimensional feature set. Further, we extract clusters which provide a compact representation of the essential information in these features. The main idea in this paper is to incorporate these clustered features into the 3D variational segmentation framework. In contrast to the previous variational approaches, we propose a segmentation method that evolves the contour in a supervised fashion. The segmentation boundary is driven by the learned inside and outside region voxel probabilities in the cluster space. We incorporate prior knowledge about the normal brain tissue appearance, during the estimation of these region statistics. In particular, we use a Dirichlet prior that discourages the clusters in the ventricles to be in the tumor and hence better disambiguate the tumor from brain tissue. We show the performance of our method on real MRI scans. The experimental dataset includes MRI scans, from patients with difficult instances, with tumors that are inhomogeneous in appearance, small in size and in proximity to the major structures in the brain. Our method shows good results on these test cases.

Image fusion pitfalls for cranial radiosurgery.

PubMed

Jonker, Benjamin P

2013-01-01

Stereotactic radiosurgery requires imaging to define both the stereotactic space in which the treatment is delivered and the target itself. Image fusion is the process of using rotation and translation to bring a second image set into alignment with the first image set. This allows the potential concurrent use of multiple image sets to define the target and stereotactic space. While a single magnetic resonance imaging (MRI) sequence alone can be used for delineation of the target and fiducials, there may be significant advantages to using additional imaging sets including other MRI sequences, computed tomography (CT) scans, and advanced imaging sets such as catheter-based angiography, diffusor tension imaging-based fiber tracking and positon emission tomography in order to more accurately define the target and surrounding critical structures. Stereotactic space is usually defined by detection of fiducials on the stereotactic head frame or mask system. Unfortunately MRI sequences are susceptible to geometric distortion, whereas CT scans do not face this problem (although they have poorer resolution of the target in most cases). Thus image fusion can allow the definition of stereotactic space to proceed from the geometrically accurate CT images at the same time as using MRI to define the target. The use of image fusion is associated with risk of error introduced by inaccuracies of the fusion process, as well as workflow changes that if not properly accounted for can mislead the treating clinician. The purpose of this review is to describe the uses of image fusion in stereotactic radiosurgery as well as its potential pitfalls.

Cervical Spine MRI in Abused Infants.

ERIC Educational Resources Information Center

Feldman, Kenneth W.; And Others

1997-01-01

This study attempted to use cervical spine magnetic resonance imaging (MRI) to detect cord injury in 12 dead children with head injury from child abuse. Eighty percent of children autopsied had small cervical spine hemorrhages; MRI did not identify them and did not identify cord injury in any child studied, indicating that MRI scans are probably…

Clinical safety of an MRI conditional implantable cardioverter defibrillator system: A prospective Monocenter ICD-Magnetic resonance Imaging feasibility study (MIMI).

PubMed

Kypta, Alexander; Blessberger, Hermann; Hoenig, Simon; Saleh, Karim; Lambert, Thomas; Kammler, Juergen; Fellner, Franz; Lichtenauer, Michael; Steinwender, Clemens

2016-03-01

The aim of this study was to evaluate the safety and efficacy of the Lumax 740(®) Implantable Cardioverter Defibrillator (ICD) system in patients undergoing a defined 1.5 Tesla (T) MRI. Between November 2013 and April 2014, eighteen patients (age range, 41-78 years; mean age, 64 years) implanted with a Lumax 740(®) ICD system for at least 6 weeks before an MRI were enrolled into this single-center feasibility study. The local ethics committee approved the study before patients gave written informed consent. Patients underwent defined MRI 1.5T of the brain and lower lumbar spine with three safety follow-up evaluations obtained during the 3-month study period. Data were analyzed descriptively. Study endpoints were the absence of either MRI and pacing system related serious adverse device effects (SADE), or of a ventricular pacing threshold increase >0.5V, or of an R-wave amplitude attenuation < 50%, or of an R-wave amplitude < 5.0 mV at 1-month follow-up. The assessment of safety and efficacy was supported by recording of all adverse events, changes in pacing threshold, R-wave sensing, pacing impedances and in battery status. Sixteen patients completed the MRI and the follow-up period. As no SADE occurred, the SADE free rate was 100%. Freedom from ventricular pacing threshold increase was 100% (16/16; 95%CI: 82.9%; 100.0%). There were no significant differences between baseline and follow-up measurements of sensing amplitudes (-0.58 ± 2.07 mV, P = 0.239, -0.41 ± 1.04 mV, P = 0.133, and -0.25 ± 1.36 mV, P = 0.724, for immediately after, 1 month and 3 months after MRI scan, respectively) and pacing thresholds (-0.047 ± 0.18 V, P = 0.317, -0.019 ± 0.11 V, P = 0.490, and 0.075 ± 0.19 V, P = 0.070, for immediately after, 1 month and 3 months after MRI scan, respectively). Lead impedances after the MRI scan were significantly lower as compared with baseline values (-22.8 ± 21.69 Ω, P = 0.001, -21.62 ± 39.71 Ω, P = 0.040, and -33.68 ± 57.73 Ω, P = 0.018, for immediately after, 1 month and 3 months after MRI scan, respectively). MRI scans in patients with MRI conditional ICD system (Lumax 740(®) ) are feasible and can be performed safely under defined conditions in a hospital setting. © 2015 Wiley Periodicals, Inc.

Common MRI acquisition non-idealities significantly impact the output of the boundary shift integral method of measuring brain atrophy on serial MRI.

PubMed

Preboske, Gregory M; Gunter, Jeff L; Ward, Chadwick P; Jack, Clifford R

2006-05-01

Measuring rates of brain atrophy from serial magnetic resonance imaging (MRI) studies is an attractive way to assess disease progression in neurodegenerative disorders, particularly Alzheimer's disease (AD). A widely recognized approach is the boundary shift integral (BSI). The objective of this study was to evaluate how several common scan non-idealities affect the output of the BSI algorithm. We created three types of image non-idealities between the image volumes in a serial pair used to measure between-scan change: inconsistent image contrast between serial scans, head motion, and poor signal-to-noise (SNR). In theory the BSI volume difference measured between each pair of images should be zero and any deviation from zero should represent corruption of the BSI measurement by some non-ideality intentionally introduced into the second scan in the pair. Two different BSI measures were evaluated, whole brain and ventricle. As the severity of motion, noise, and non-congruent image contrast increased in the second scan, the calculated BSI values deviated progressively more from the expected value of zero. This study illustrates the magnitude of the error in measures of change in brain and ventricle volume across serial MRI scans that can result from commonly encountered deviations from ideal image quality. The magnitudes of some of the measurement errors seen in this study exceed the disease effect in AD shown in various publications, which range from 1% to 2.78% per year for whole brain atrophy and 5.4% to 13.8% per year for ventricle expansion (Table 1). For example, measurement error may exceed 100% if image contrast properties dramatically differ between the two scans in a measurement pair. Methods to maximize consistency of image quality over time are an essential component of any quantitative serial MRI study.

Does hydration status affect MRI measures of brain volume or water content?

PubMed

Meyers, Sandra M; Tam, Roger; Lee, Jimmy S; Kolind, Shannon H; Vavasour, Irene M; Mackie, Emilie; Zhao, Yinshan; Laule, Cornelia; Mädler, Burkhard; Li, David K B; MacKay, Alex L; Traboulsee, Anthony L

2016-08-01

To determine whether differences in hydration state, which could arise from routine clinical procedures such as overnight fasting, affect brain total water content (TWC) and brain volume measured with magnetic resonance imaging (MRI). Twenty healthy volunteers were scanned with a 3T MR scanner four times: day 1, baseline scan; day 2, hydrated scan after consuming 3L of water over 12 hours; day 3, dehydrated scan after overnight fasting of 9 hours, followed by another scan 1 hour later for reproducibility. The following MRI data were collected: T2 relaxation (for TWC measurement), inversion recovery (for T1 measurement), and 3D T1 -weighted (for brain volumes). Body weight and urine specific gravity were also measured. TWC was calculated by fitting the T2 relaxation data with a nonnegative least-squares algorithm, with corrections for T1 relaxation and image signal inhomogeneity and normalization to ventricular cerebrospinal fluid. Brain volume changes were measured using SIENA. TWC means were calculated within 14 tissue regions. Despite indications of dehydration as demonstrated by increases in urine specific gravity (P = 0.03) and decreases in body weight (P = 0.001) between hydrated and dehydrated scans, there was no measurable change in TWC (within any brain region) or brain volume between hydration states. We demonstrate that within a range of physiologic conditions commonly encountered in routine clinical scans (no pretreatment with hydration, well hydrated before MRI, and overnight fasting), brain TWC and brain volumes are not substantially affected in a healthy control cohort. J. Magn. Reson. Imaging 2016;44:296-304. © 2016 Wiley Periodicals, Inc.

Reliability of fMRI for Studies of Language in Post-Stroke Aphasia Subjects

PubMed Central

Eaton, Kenneth P.; Szaflarski, Jerzy P.; Altaye, Mekibib; Ball, Angel L.; Kissela, Brett M.; Banks, Christi; Holland, Scott K.

2008-01-01

Quantifying change in brain activation patterns associated with post-stroke recovery and reorganization of language function over time requires accurate understanding of inter-scan and inter-subject variability. Here we report inter-scan variability measures for fMRI activation patterns associated with verb generation (VG) and semantic decision/tone decision (SDTD) tasks in 4 healthy controls and 4 aphasic left middle cerebral artery (LMCA) stroke subjects. A series of 10 fMRI scans was completed on a 4T Varian scanner for each task for each subject, except for one stroke subject who completed 5 and 6 scans for SDTD and VG, thus yielding 35 and 36 total stroke subject scans for SDTD and VG, respectively. Group composite and intraclass correlation coefficient (ICC) maps were computed across all subjects and trials for each task. The patterns of reliable activation for the VG and SDTD tasks correspond well to those regions typically activated by these tasks in healthy and aphasic subjects. ICCs for activation were consistently high (R0.05 ≈ 0.8) for individual tasks among both control and aphasic subjects. These voxel-wise measures of reliability highlight regions of low inter-scan variability within language circuitry for control and post-recovery stroke subjects. ICCs computed from the combination of the SDTD/VG data were markedly reduced for both control and aphasic subjects as compared with the ICCs for the individual tasks. These quantitative measures of inter-scan variability support the proposed use of these fMRI paradigms for longitudinal mapping of neural reorganization of language processing following left hemispheric insult. PMID:18411061

MRI assessment of suppression of structural damage in patients with rheumatoid arthritis receiving rituximab: results from the randomised, placebo-controlled, double-blind RA-SCORE study.

PubMed

Peterfy, Charles; Emery, Paul; Tak, Paul P; Østergaard, Mikkel; DiCarlo, Julie; Otsa, Kati; Navarro Sarabia, Federico; Pavelka, Karel; Bagnard, Marie-Agnes; Gylvin, Lykke Hinsch; Bernasconi, Corrado; Gabriele, Annarita

2016-01-01

To evaluate changes in structural damage and joint inflammation assessed by MRI following rituximab treatment in a Phase 3 study of patients with active rheumatoid arthritis (RA) despite methotrexate (MTX) who were naive to biological therapy. Patients were randomised to receive two infusions of placebo (n=63), rituximab 500 mg (n=62), or rituximab 1000 mg (n=60) intravenously on days 1 and 15. MRI scans and radiographs of the most inflamed hand and wrist were acquired at baseline, weeks 12 (MRI only), 24 and 52. The primary end point was the change in MRI erosion score from baseline at week 24. Patients treated with rituximab demonstrated significantly less progression in the mean MRI erosion score compared with those treated with placebo at weeks 24 (0.47, 0.18 and 1.60, respectively, p=0.003 and p=0.001 for the two rituximab doses vs placebo) and 52 (-0.30, 0.11 and 3.02, respectively; p<0.001 and p<0.001). Cartilage loss at 52 weeks was significantly reduced in the rituximab group compared with the placebo group. Other secondary end points of synovitis and osteitis improved significantly with rituximab compared with placebo as early as 12 weeks and improved further at weeks 24 and 52. This study demonstrated that rituximab significantly reduced erosion and cartilage loss at week 24 and week 52 in MTX-inadequate responder patients with active RA, suggesting that MRI is a valuable tool for assessing inflammatory and structural damage in patients with established RA receiving rituximab. NCT00578305. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Advanced MRI in Blast-related TBI

DTIC Science & Technology

2012-07-01

test two advanced MRI methods, DTI and resting-state fMRI, in active-duty military blast-related TBI patients acutely after injury and correlate...Introduction: The purpose of the research effort was to test two advanced MRI methods, DTI and resting-state fMRI, in active-duty military blast-related TBI...clinical follow-up assessments and repeat scans on 78 subjects with TBI and 18 controls. 9) We extensively analyzed DTI , resting-state fMRI, and

Post-stenotic plug-like jet with a vortex ring demonstrated by 4D flow MRI.

PubMed

Kim, Guk Bae; Ha, Hojin; Kweon, Jihoon; Lee, Sang Joon; Kim, Young-Hak; Yang, Dong Hyun; Kim, Namkug

2016-05-01

To investigate the details of the flow structure of a plug-like jet that had a vortex ring in pulsatile stenotic phantoms using 4D flow MRI. Pulsatile Newtonian flows in two stenotic phantoms with 50% and 75% reductions in area were scanned by 4D flow MRI. Blood analog working fluid was circulated via the stenotic phantom using a pulsatile pump at a constant pulsating frequency of 1Hz. The velocity and vorticity fields of the plug-like jet with a vortex ring were quantitatively analyzed in the spatial and temporal domains. Pulsatile stenotic flow showed a plug-like jet at the specific stenotic degree of 50% in our pulsatile waveform design. This plug-like jet was found at the decelerating period in the post-stenotic region of 26.4mm (1.2 D). It revealed a vortex ring structure with vorticity strength in the range of ±100s(-1). We observed a plug-like jet with a vortex ring in pulsatile stenotic flow by in vitro visualization using 4D flow MRI. In this plug-like jet, the local fastest flow region occurred at the post-systole phase in the post-stenotic region, which was distinguishable from a typical stenotic jet flow at systole phase. Copyright © 2015 Elsevier Inc. All rights reserved.

Novel use of gamma correction for precise (99m)Tc-HDP pinhole bone scan diagnosis and classification of knee occult fractures.

PubMed

Bahk, Yong-Whee; Jeon, Ho-Seung; Kim, Jang Min; Park, Jung Mee; Chung, Yong-An; Kim, E Edmund; Kim, Sung-Hoon; Chung, Soo-Kyo

2010-08-01

The aim of this study was to introduce gamma correction pinhole bone scan (GCPBS) to depict specific signs of knee occult fractures (OF) on (99m)Tc-hydroxydiphosphonate (HDP) scan. Thirty-six cases of six different types of knee OF in 27 consecutive patients (male = 20, female = 7, and age = 18-86 years) were enrolled. The diagnosis was made on the basis of a history of acute or subacute knee trauma, local pain, tenderness, cutaneous injury, negative conventional radiography, and positive magnetic resonance imaging (MRI). Because of the impracticability of histological verification of individual OF, MRI was utilized as a gold standard of diagnosis and classification. All patients had (99m)Tc-HDP bone scanning and supplementary GCPBS. GCPBS signs were correlated and compared with those of MRI. The efficacy of gamma correction of ordinary parallel collimator and pinhole collimator scans were collated. Gamma correction pinhole bone scan depicted the signs characteristic of six different types of OF. They were well defined stuffed globular tracer uptake in geographic I fractures (n = 9), block-like uptake in geographic II fractures (n = 7), simple or branching linear uptake in linear cancellous fractures (n = 4), compression in impacted fractures (n = 2), stippled-serpentine uptake in reticular fractures (n = 11), and irregular subcortical uptake in osteochondral fractures (n = 3). All fractures were equally well or more distinctly depicted on GCPBS than on MRI except geographic II fracture, the details of which were not appreciated on GCPBS. Parallel collimator scan also yielded to gamma correction, but the results were inferior to those of the pinhole scan. Gamma correction pinhole bone scan can depict the specific diagnostic signs in six different types of knee occult fractures. The specific diagnostic capability along with the lower cost and wider global availability of bone scanning would make GCPBS an effective alternative.

Scan-rescan reproducibility of diastolic left ventricular kinetic energy, viscous energy loss and vorticity assessment using 4D flow MRI: analysis in healthy subjects.

PubMed

Kamphuis, Vivian P; Westenberg, Jos J M; van der Palen, Roel L F; van den Boogaard, Pieter J; van der Geest, Rob J; de Roos, Albert; Blom, Nico A; Roest, Arno A W; Elbaz, Mohammed S M

2018-01-05

The aim of the current study was to assess the scan-rescan reproducibility of left ventricular (LV) kinetic energy (KE), viscous energy loss (EL) and vorticity during diastole from four-dimensional flow magnetic resonance imaging (4D flow MRI) in healthy subjects. Twelve volunteers (age 27 ± 3 years) underwent whole-heart 4D flow MRI twice in one session. In-scan consistency was evaluated by correlation between KE and EL. EL index was computed to measure the amount of EL relative to KE over diastole. Scan-rescan analysis was performed to test reproducibility of volumetric measurements of KE, EL, EL index and vorticity in the LV over early (E) and late (A) diastolic filling. In-scan consistency between KE and EL was strong-excellent (E-filling scan1: r = 0.92, P < 0.001; scan2: ρ = 0.96, P < 0.001 and A-filling scan1: ρ = 0.87, P < 0.001; scan2: r = 0.99, P < 0.001). For the majority of subjects (10 out of 12), KE and EL measures showed good to strong reproducibility. However, with a wide range of agreement [intraclass correlation (ICC): 0.64-0.95] and coefficients of variation (CV) ≤ 25%. EL index showed strong reproducibility for all 12 subjects with a strong ICC (0.94, P < 0.001) and a CV of 9%. Scan-rescan reproducibility of volumetric vorticity showed good-excellent ICCs (0.83-0.95) with CVs ≤ 11%. In conclusion, the current study shows strong-excellent in-scan consistency and overall good agreement between scans for 4D flow MRI assessment of left ventricular kinetic energy, energy loss and vorticity over diastole. However, substantial differences between the scans were also found in some parameters in two out of twelve subjects. Strong reproducibility was found in the dimensionless EL index , which measures the amount of viscous energy loss relative to the average kinetic energy over diastole.

Reliability Correction for Functional Connectivity: Theory and Implementation

PubMed Central

Mueller, Sophia; Wang, Danhong; Fox, Michael D.; Pan, Ruiqi; Lu, Jie; Li, Kuncheng; Sun, Wei; Buckner, Randy L.; Liu, Hesheng

2016-01-01

Network properties can be estimated using functional connectivity MRI (fcMRI). However, regional variation of the fMRI signal causes systematic biases in network estimates including correlation attenuation in regions of low measurement reliability. Here we computed the spatial distribution of fcMRI reliability using longitudinal fcMRI datasets and demonstrated how pre-estimated reliability maps can correct for correlation attenuation. As a test case of reliability-based attenuation correction we estimated properties of the default network, where reliability was significantly lower than average in the medial temporal lobe and higher in the posterior medial cortex, heterogeneity that impacts estimation of the network. Accounting for this bias using attenuation correction revealed that the medial temporal lobe’s contribution to the default network is typically underestimated. To render this approach useful to a greater number of datasets, we demonstrate that test-retest reliability maps derived from repeated runs within a single scanning session can be used as a surrogate for multi-session reliability mapping. Using data segments with different scan lengths between 1 and 30 min, we found that test-retest reliability of connectivity estimates increases with scan length while the spatial distribution of reliability is relatively stable even at short scan lengths. Finally, analyses of tertiary data revealed that reliability distribution is influenced by age, neuropsychiatric status and scanner type, suggesting that reliability correction may be especially important when studying between-group differences. Collectively, these results illustrate that reliability-based attenuation correction is an easily implemented strategy that mitigates certain features of fMRI signal nonuniformity. PMID:26493163

Same-session functional assessment of rat retina and brain with manganese-enhanced MRI

PubMed Central

Bissig, David; Berkowitz, Bruce A.

2013-01-01

Manganese-enhanced MRI (MEMRI) is a powerful non-invasive approach for objectively measuring either retina or binocular visual brain activity in vivo. In this study, we investigated the sensitivity of MEMRI to monocular stimulation using a new protocol for providing within-subject functional comparisons in the retina and brain in the same scanning session. Adult Sprague Dawley or Long–Evans rats had one eye covered with an opaque patch. After intraperitoneal Mn2+ administration on the following day, rats underwent visual stimulation for 8 h. Animals were then anesthetized, and the brain and each eye examined by MEMRI. Function was assessed through pairwise comparisons of the patched (dark-adapted) versus unpatched (light-exposed) eyes, and of differentially-stimulated brain structures – the dorsal lateral geniculate nucleus, superior colliculus, and visual cortical regions – contralateral to the patched versus unpatched eye. As expected, Mn2+ uptake was greater in the outer retina of dark-adapted, relative to light-exposed, eyes (P<0.05). Contralateral to the unpatched eye, significantly more Mn2+ uptake was found throughout the visual brain regions than in the corresponding structures contralateral to the patched eye (P<0.05). Notably, this regional pattern of activity corresponded well to previous work with monocular stimulation. No stimulation-dependent differences in Mn2+ uptake were observed in negative control brain regions (P>0.05). Post-hoc assessment of functional data by animal age and strain revealed no significant effects. These results demonstrate, for the first time, the acquisition of functional MRI data from the eye and visual brain regions in a single scanning session. PMID:21749922

Marked brain asymmetry with intact cognitive functioning in idiopathic Parkinson's disease: a longitudinal analysis.

PubMed

Tanner, Jared J; Levy, Shellie-Anne; Schwab, Nadine A; Hizel, Loren P; Nguyen, Peter T; Okun, Michael S; Price, Catherine C

2017-04-01

A 71-year-old (MN) with an 11-year history of left onset tremor diagnosed as Parkinson's disease (PD) completed longitudinal brain magnetic resonance imaging (MRI) and neuropsychological testing. MRI scans showed an asymmetric caudate nucleus (right < left volume). We describe this asymmetry at baseline and the progression over time relative to other subcortical gray, frontal white matter, and cortical gray matter regions of interest. Isolated structural changes are compared to MN's cognitive profiles. MN completed yearly MRIs and neuropsychological assessments. For comparison, left onset PD (n = 15) and non-PD (n = 43) peers completed the same baseline protocol. All MRI scans were processed with FreeSurfer and the FMRIB Software Library to analyze gray matter structures and frontal fractional anisotropy (FA) metrics. Processing speed, working memory, language, verbal memory, abstract reasoning, visuospatial, and motor functions were examined using reliable change methods. At baseline, MN had striatal volume and frontal lobe thickness asymmetry relative to peers with mild prefrontal white matter FA asymmetry. Over time only MN's right caudate nucleus showed accelerated atrophy. Cognitively, MN had slowed psychomotor speed and visuospatial-linked deficits with mild visuospatial working memory declines longitudinally. This is a unique report using normative neuroimaging and neuropsychology to describe an individual diagnosed with PD who had striking striatal asymmetry followed secondarily by cortical thickness asymmetry and possible frontal white matter asymmetry. His decline and variability in visual working memory could be linked to ongoing atrophy of his right caudate nucleus.

Marked brain asymmetry with intact cognitive functioning in idiopathic Parkinson’s disease: A longitudinal analysis

PubMed Central

Tanner, Jared J.; Levy, Shellie-Anne; Schwab, Nadine A.; Hizel, Loren P.; Nguyen, Peter T.; Okun, Michael S.; Price, Catherine C.

2016-01-01

Objective A 71-year old (MN) with an 11-year history of left onset tremor diagnosed as Parkinson’s disease (PD) completed longitudinal brain magnetic resonance imaging (MRI) and neuropsychological testing. MRI scans showed an asymmetric caudate nucleus (right< left volume). We describe this asymmetry at baseline and the progression over time relative to other subcortical gray, frontal white matter, and cortical gray matter regions of interest. Isolated structural changes are compared to MN’s cognitive profiles. Method MN completed yearly MRIs and neuropsychological assessments. For comparison, left onset PD (n=15) and non-PD (n=43) peers completed the same baseline protocol. All MRI scans were processed with FreeSurfer and the FMRIB Software Library (FSL) to analyze gray matter structures and frontal fractional anisotropy (FA) metrics. Processing speed, working memory, language, verbal memory, abstract reasoning, visuospatial, and motor functions were examined using reliable change methods. Results At baseline MN had striatal volume and frontal lobe thickness asymmetry relative to peers with mild prefrontal white matter FA asymmetry. Over time only MN’s right caudate nucleus showed accelerated atrophy. Cognitively, MN had slowed psychomotor speed and visuospatial-linked deficits with mild visuospatial working memory declines longitudinally. Conclusions This is a unique report using normative neuroimaging and neuropsychology to describe an individual diagnosed with PD who had striking striatal asymmetry followed secondarily by cortical thickness asymmetry and possible frontal white matter asymmetry. His decline and variability in visual working memory could be linked to ongoing atrophy of his right caudate nucleus. PMID:27813459

Validation of Automated White Matter Hyperintensity Segmentation

PubMed Central

Smart, Sean D.; Firbank, Michael J.; O'Brien, John T.

2011-01-01

Introduction. White matter hyperintensities (WMHs) are a common finding on MRI scans of older people and are associated with vascular disease. We compared 3 methods for automatically segmenting WMHs from MRI scans. Method. An operator manually segmented WMHs on MRI images from a 3T scanner. The scans were also segmented in a fully automated fashion by three different programmes. The voxel overlap between manual and automated segmentation was compared. Results. Between observer overlap ratio was 63%. Using our previously described in-house software, we had overlap of 62.2%. We investigated the use of a modified version of SPM segmentation; however, this was not successful, with only 14% overlap. Discussion. Using our previously reported software, we demonstrated good segmentation of WMHs in a fully automated fashion. PMID:21904678

CAIPIRINHA accelerated SPACE enables 10-min isotropic 3D TSE MRI of the ankle for optimized visualization of curved and oblique ligaments and tendons.

PubMed

Kalia, Vivek; Fritz, Benjamin; Johnson, Rory; Gilson, Wesley D; Raithel, Esther; Fritz, Jan

2017-09-01

To test the hypothesis that a fourfold CAIPIRINHA accelerated, 10-min, high-resolution, isotropic 3D TSE MRI prototype protocol of the ankle derives equal or better quality than a 20-min 2D TSE standard protocol. Following internal review board approval and informed consent, 3-Tesla MRI of the ankle was obtained in 24 asymptomatic subjects including 10-min 3D CAIPIRINHA SPACE TSE prototype and 20-min 2D TSE standard protocols. Outcome variables included image quality and visibility of anatomical structures using 5-point Likert scales. Non-parametric statistical testing was used. P values ≤0.001 were considered significant. Edge sharpness, contrast resolution, uniformity, noise, fat suppression and magic angle effects were without statistical difference on 2D and 3D TSE images (p > 0.035). Fluid was mildly brighter on intermediate-weighted 2D images (p < 0.001), whereas 3D images had substantially less partial volume, chemical shift and no pulsatile-flow artifacts (p < 0.001). Oblique and curved planar 3D images resulted in mildly-to-substantially improved visualization of joints, spring, bifurcate, syndesmotic, collateral and sinus tarsi ligaments, and tendons (p < 0.001, respectively). 3D TSE MRI with CAIPIRINHA acceleration enables high-spatial resolution oblique and curved planar MRI of the ankle and visualization of ligaments, tendons and joints equally well or better than a more time-consuming anisotropic 2D TSE MRI. • High-resolution 3D TSE MRI improves visualization of ankle structures. • Limitations of current 3D TSE MRI include long scan times. • 3D CAIPIRINHA SPACE allows now a fourfold-accelerated data acquisition. • 3D CAIPIRINHA SPACE enables high-spatial-resolution ankle MRI within 10 min. • 10-min 3D CAIPIRINHA SPACE produces equal-or-better quality than 20-min 2D TSE.

Serial magnetic resonance imaging of metal-on-metal total hip replacements. Follow-up of a cohort of 28 mm Ultima TPS THRs.

PubMed

Ebreo, D; Bell, P J; Arshad, H; Donell, S T; Toms, A; Nolan, J F

2013-08-01

Metal artefact reduction (MAR) MRI is now widely considered to be the standard for imaging metal-on-metal (MoM) hip implants. The Medicines and Healthcare Products Regulatory Agency (MHRA) has recommended cross-sectional imaging for all patients with symptomatic MoM bearings. This paper describes the natural history of MoM disease in a 28 mm MoM total hip replacement (THR) using MAR MRI. Inclusion criteria were patients with MoM THRs who had not been revised and had at least two serial MAR MRI scans. All examinations were reported by an experienced observer and classified as A (normal), B (infection) or C1-C3 (mild, moderate, severe MoM-related abnormalities). Between 2002 and 2011 a total of 239 MRIs were performed on 80 patients (two to four scans per THR); 63 initial MRIs (61%) were normal. On subsequent MRIs, six initially normal scans (9.5%) showed progression to a disease state; 15 (15%) of 103 THRs with sequential scans demonstrated worsening disease on subsequent imaging. Most patients with a MoM THR who do not undergo early revision have normal MRI scans. Late progression (from normal to abnormal, or from mild to more severe MoM disease) is not common and takes place over several years.

Oedema of the abductor digiti quinti muscle due to subacute denervation: report of two cases.

PubMed

Chimutengwende-Gordon, Mukai; O'Donnell, Paul; Cullen, Nicholas; Singh, Dishan

2014-03-01

The clinical presentation of abductor digiti quinti (ADQ) denervation is often non-specific. The diagnosis is generally clinical and may be easily missed. This case report of two patients describes the magnetic resonance imaging (MRI) finding of unilateral oedema and fatty infiltration isolated to the ADQ. A 36-year old woman who presented with laterally located left foot pain was initially diagnosed as having plantar fasciitis. An MRI scan arranged due to the unusual site of the pain showed increased signal intensity within the ADQ muscle on T1 and T2 images indicating fatty infiltration. Short tau inversion recovery (STIR) images showed hyperintensity of the ADQ indicating oedema. The MRI scan of a 45-year old man who presented with a three month history of left heel pain revealed similar findings. These MRI appearances indicate subacute denervation, which, when involving solely the ADQ muscle suggests entrapment of the first branch of the lateral plantar nerve. Consideration of this imaging finding when examining MRI scans of patients with non-specific heel pain has the potential to facilitate diagnosis. Copyright © 2013 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Ionising radiation-free whole-body MRI versus (18)F-fluorodeoxyglucose PET/CT scans for children and young adults with cancer: a prospective, non-randomised, single-centre study.

PubMed

Klenk, Christopher; Gawande, Rakhee; Uslu, Lebriz; Khurana, Aman; Qiu, Deqiang; Quon, Andrew; Donig, Jessica; Rosenberg, Jarrett; Luna-Fineman, Sandra; Moseley, Michael; Daldrup-Link, Heike E

2014-03-01

Imaging tests are essential for staging of children with cancer. However, CT and radiotracer-based imaging procedures are associated with substantial exposure to ionising radiation and risk of secondary cancer development later in life. Our aim was to create a highly effective, clinically feasible, ionising radiation-free staging method based on whole-body diffusion-weighted MRI and the iron supplement ferumoxytol, used off-label as a contrast agent. We compared whole-body diffusion-weighted MRI with standard clinical (18)F-fluorodeoxyglucose ((18)F-FDG) PET/CT scans in children and young adults with malignant lymphomas and sarcomas. Whole-body diffusion-weighted magnetic resonance images were generated by coregistration of colour-encoded ferumoxytol-enhanced whole-body diffusion-weighted MRI scans for tumour detection with ferumoxytol-enhanced T1-weighted MRI scans for anatomical orientation, similar to the concept of integrated (18)F-FDG PET/CT scans. Tumour staging results were compared using Cohen's κ statistics. Histopathology and follow-up imaging served as the standard of reference. Data was assessed in the per-protocol population. This study is registered with ClinicalTrials.gov, number NCT01542879. 22 of 23 recruited patients were analysed because one patient discontinued before completion of the whole-body scan. Mean exposure to ionising radiation was 12·5 mSv (SD 4·1) for (18)F-FDG PET/CT compared with zero for whole-body diffusion-weighted MRI. (18)F-FDG PET/CT detected 163 of 174 malignant lesions at 1325 anatomical regions and whole-body diffusion-weighted MRI detected 158. Comparing (18)F-FDG PET/CT to whole-body diffusion-weighted MRI, sensitivities were 93·7% (95% CI 89·0-96·8) versus 90·8% (85·5-94·7); specificities 97·7% (95% CI 96·7-98·5) versus 99·5% (98·9-99·8); and diagnostic accuracies 97·2% (93·6-99·4) versus 98·3% (97·4-99·2). Tumour staging results showed very good agreement between both imaging modalities with a κ of 0·93 (0·81-1·00). No adverse events after administration of ferumoxytol were recorded. Ferumoxytol-enhanced whole-body diffusion-weighted MRI could be an alternative to (18)F-FDG PET/CT for staging of children and young adults with cancer that is free of ionising radiation. This new imaging test might help to prevent long-term side-effects from radiographic staging procedures. Thrasher Research Fund and Clinical Health Research Institute at Stanford University. Copyright © 2014 Elsevier Ltd. All rights reserved.

Regression and statistical shape model based substitute CT generation for MRI alone external beam radiation therapy from standard clinical MRI sequences.

PubMed

Ghose, Soumya; Greer, Peter B; Sun, Jidi; Pichler, Peter; Rivest-Henault, David; Mitra, Jhimli; Richardson, Haylea; Wratten, Chris; Martin, Jarad; Arm, Jameen; Best, Leah; Dowling, Jason A

2017-10-27

In MR only radiation therapy planning, generation of the tissue specific HU map directly from the MRI would eliminate the need of CT image acquisition and may improve radiation therapy planning. The aim of this work is to generate and validate substitute CT (sCT) scans generated from standard T2 weighted MR pelvic scans in prostate radiation therapy dose planning. A Siemens Skyra 3T MRI scanner with laser bridge, flat couch and pelvic coil mounts was used to scan 39 patients scheduled for external beam radiation therapy for localized prostate cancer. For sCT generation a whole pelvis MRI (1.6 mm 3D isotropic T2w SPACE sequence) was acquired. Patients received a routine planning CT scan. Co-registered whole pelvis CT and T2w MRI pairs were used as training images. Advanced tissue specific non-linear regression models to predict HU for the fat, muscle, bladder and air were created from co-registered CT-MRI image pairs. On a test case T2w MRI, the bones and bladder were automatically segmented using a novel statistical shape and appearance model, while other soft tissues were separated using an Expectation-Maximization based clustering model. The CT bone in the training database that was most 'similar' to the segmented bone was then transformed with deformable registration to create the sCT component of the test case T2w MRI bone tissue. Predictions for the bone, air and soft tissue from the separate regression models were successively combined to generate a whole pelvis sCT. The change in monitor units between the sCT-based plans relative to the gold standard CT plan for the same IMRT dose plan was found to be [Formula: see text] (mean  ±  standard deviation) for 39 patients. The 3D Gamma pass rate was [Formula: see text] (2 mm/2%). The novel hybrid model is computationally efficient, generating an sCT in 20 min from standard T2w images for prostate cancer radiation therapy dose planning and DRR generation.

Regression and statistical shape model based substitute CT generation for MRI alone external beam radiation therapy from standard clinical MRI sequences

NASA Astrophysics Data System (ADS)

Ghose, Soumya; Greer, Peter B.; Sun, Jidi; Pichler, Peter; Rivest-Henault, David; Mitra, Jhimli; Richardson, Haylea; Wratten, Chris; Martin, Jarad; Arm, Jameen; Best, Leah; Dowling, Jason A.

2017-11-01

In MR only radiation therapy planning, generation of the tissue specific HU map directly from the MRI would eliminate the need of CT image acquisition and may improve radiation therapy planning. The aim of this work is to generate and validate substitute CT (sCT) scans generated from standard T2 weighted MR pelvic scans in prostate radiation therapy dose planning. A Siemens Skyra 3T MRI scanner with laser bridge, flat couch and pelvic coil mounts was used to scan 39 patients scheduled for external beam radiation therapy for localized prostate cancer. For sCT generation a whole pelvis MRI (1.6 mm 3D isotropic T2w SPACE sequence) was acquired. Patients received a routine planning CT scan. Co-registered whole pelvis CT and T2w MRI pairs were used as training images. Advanced tissue specific non-linear regression models to predict HU for the fat, muscle, bladder and air were created from co-registered CT-MRI image pairs. On a test case T2w MRI, the bones and bladder were automatically segmented using a novel statistical shape and appearance model, while other soft tissues were separated using an Expectation-Maximization based clustering model. The CT bone in the training database that was most ‘similar’ to the segmented bone was then transformed with deformable registration to create the sCT component of the test case T2w MRI bone tissue. Predictions for the bone, air and soft tissue from the separate regression models were successively combined to generate a whole pelvis sCT. The change in monitor units between the sCT-based plans relative to the gold standard CT plan for the same IMRT dose plan was found to be 0.3%+/-0.9% (mean  ±  standard deviation) for 39 patients. The 3D Gamma pass rate was 99.8+/-0.00 (2 mm/2%). The novel hybrid model is computationally efficient, generating an sCT in 20 min from standard T2w images for prostate cancer radiation therapy dose planning and DRR generation.

MO-FG-CAMPUS-IeP3-01: Evaluation of Specific Absorption Rate and Temperature Increase Induced by Artificial Medical Implants During MRI Scan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seo, Y

Purpose: Heating of patients or burning of biological tissues around medical implants by RF power during MRI scan is a significant patient safety concern. The purpose of this study is to not only measure SAR values, but also RF-induced temperature elevation due to artificial hip joints during MRI scans. Methods: SAR measurement experiment was performed on three discrete manufacturers at 1.5 and 3T. Three MRI RF sequences (T1w TSE, T2w inversion recovery, and T2w TSE) with imaging parameters were selected. A gelled saline phantom mimicking human body tissue was made (Fig.1). FDTD method was utilized to calculate the SAR distributionmore » using Sim4Life software. Based on the results of the simulation, 4 electrical field (E-field) sensors were located around two artificial hip joints inside the phantom. 56 Fiber Bragg Grating (FBG) temperature sensors (28 sensors on each artificial hip joint) were located on both left and right artificial hip joints to measure temperature change during MRI scan (Fig.1). Both E-field and FBG temperature sensors were calibrated with traceability at Korea Research Institute of Standards and Science (KRISS). Results: Simulation shows that high SAR values occur in the head and tail of the implanted artificial hip joints (Fig.1 lower right). 3T MRI scanner shows that the local averaged-SAR values measured by probe 1, 2, and 3 are 2.30, 2.77, and 1.68 W/kg, compared to MRI scanner-reported whole body SAR value (≤1.5 W/kg) for T1w TSE and T2w-IR (Table 1). The maximum temperature elevation measured by FBG sensors is 1.49°C at 1.5 T, 2.0°C at 3 T, and 2.56°C at 3 T for T1w TSE, respectively (Table 2). Conclusion: It is essential to assess the safety of MRI system for patient with medical implant by measuring not only accurate SAR deposited in the body, but also temperature elevation due to the deposited SAR during clinical MRI.« less

Preliminary findings on the safety of 1.5 and 3 Tesla magnetic resonance imaging in cardiac pacemaker patients.

PubMed

van Dijk, Vincent F; Delnoy, Peter Paul H M; Smit, Jaap Jan J; Ramdat Misier, R Anand; Elvan, Arif; van Es, H Wouter; Rensing, Benno J W M; Raciti, Giovanni; Boersma, Lucas V A

2017-07-01

Modern pacemakers are designed to allow patients to undergo magnetic resonance imaging (MRI) under a set of specific conditions. Aim of this study is to provide confirmatory evidence of safety and performance of a new pacing system (ImageReady™, Boston Scientific) in patients undergoing 1.5 and 3T MRI. Two prospective, nonrandomized, single-arm studies were designed to provide confirmatory data of no impact of MRI on device function, lead parameters, and patient conditions in subjects implanted with the system undergoing a clinically non-indicated 1.5T and 3T MRI, respectively. Device measurements were done within 1 hour before and after the scan and at 1 month follow-up. Thirty-two subjects underwent MRI visit (17 subjects with 1.5T MRI and 15 subjects with 3T MRI). There were no unanticipated adverse effects related to the pacemaker. Device measurements taken pre- and post-MRI scan did not show any clinical relevant change that could indicate an effect of the MRI on the device or at the lead-tissue interface (RV threshold change: 0.01 ± 0.13 V, P = 0.60; RA threshold change: 0.01 ± 0.11 V, P = 0.53; R wave change: -0.44 ± 1.73 mV, P = 0.36; R wave change: 0.12 ± 1.67 mV, P = 0.73), with data confirmed at 1-month follow-up visit. The study documented safety of the pacing system in the 1.5T and 3T MRI environment by showing no adverse events related to device or MRI scan. Additional data are required to cover the more complex scenarios involving different diagnostic needs, conditions of use, clinical conditions, and new emerging technologies. © 2017 Wiley Periodicals, Inc.

Discrete pre-processing step effects in registration-based pipelines, a preliminary volumetric study on T1-weighted images.

PubMed

Muncy, Nathan M; Hedges-Muncy, Ariana M; Kirwan, C Brock

2017-01-01

Pre-processing MRI scans prior to performing volumetric analyses is common practice in MRI studies. As pre-processing steps adjust the voxel intensities, the space in which the scan exists, and the amount of data in the scan, it is possible that the steps have an effect on the volumetric output. To date, studies have compared between and not within pipelines, and so the impact of each step is unknown. This study aims to quantify the effects of pre-processing steps on volumetric measures in T1-weighted scans within a single pipeline. It was our hypothesis that pre-processing steps would significantly impact ROI volume estimations. One hundred fifteen participants from the OASIS dataset were used, where each participant contributed three scans. All scans were then pre-processed using a step-wise pipeline. Bilateral hippocampus, putamen, and middle temporal gyrus volume estimations were assessed following each successive step, and all data were processed by the same pipeline 5 times. Repeated-measures analyses tested for a main effects of pipeline step, scan-rescan (for MRI scanner consistency) and repeated pipeline runs (for algorithmic consistency). A main effect of pipeline step was detected, and interestingly an interaction between pipeline step and ROI exists. No effect for either scan-rescan or repeated pipeline run was detected. We then supply a correction for noise in the data resulting from pre-processing.

The promise of dynamic contrast-enhanced imaging in radiation therapy.

PubMed

Cao, Yue

2011-04-01

Dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and computed tomography (CT) scanning are emerging as valuable tools to quantitatively map the spatial distribution of vascular parameters, such as perfusion, vascular permeability, blood volume, and mean transit time in tumors and normal organs. DCE MRI/CT have shown prognostic and predictive value for response of certain cancers to chemotherapy and radiation therapy. DCE MRI/CT offer the promise of early assessment of tumor response to radiation therapy, opening a window for adaptively optimizing radiation therapy based upon functional alterations that occur earlier than morphologic changes. DCE MRI/CT has also shown the potential of mapping dose responses in normal organs and tissue for evaluation of individual sensitivity to radiation, providing additional opportunities to minimize risks of radiation injury. The evidence for potentially applying DCE MRI and CT for selection and delineation of radiation boost targets is growing. The clinical use of DCE MRI and CT scanning as a biomarker or even a surrogate endpoint for radiation therapy assessment of tumor and normal organs must consider technical validation issues, including standardization, reproducibility, accuracy and robustness, and clinical validation of the sensitivity and specificity for each specific problem of interest. Although holding great promise, to date, DCE MRI and CT scanning have not been qualified as a surrogate endpoint for radiation therapy assessment or for treatment modification in any prospective phase III clinical trial for any tumor site. Copyright © 2011 Elsevier Inc. All rights reserved.

Using radioactive drugs could lead to better imaging of prostate cancer | Center for Cancer Research

Cancer.gov

Medical imaging (x-ray, ultrasound, MRI, CT, PET scan) is a noninvasive way to view the internal structures of the body. However, these tools are not ideal for detecting cancer that has spread, or metastasized, because the precise location of these cancer cells is unknown. Researchers are now testing an experimental radiotracer called 18F-DCFPyL to help find sites of cancer in

Navigation-supported diagnosis of the substantia nigra by matching midbrain sonography and MRI

NASA Astrophysics Data System (ADS)

Salah, Zein; Weise, David; Preim, Bernhard; Classen, Joseph; Rose, Georg

2012-03-01

Transcranial sonography (TCS) is a well-established neuroimaging technique that allows for visualizing several brainstem structures, including the substantia nigra, and helps for the diagnosis and differential diagnosis of various movement disorders, especially in Parkinsonian syndromes. However, proximate brainstem anatomy can hardly be recognized due to the limited image quality of B-scans. In this paper, a visualization system for the diagnosis of the substantia nigra is presented, which utilizes neuronavigated TCS to reconstruct tomographical slices from registered MRI datasets and visualizes them simultaneously with corresponding TCS planes in realtime. To generate MRI tomographical slices, the tracking data of the calibrated ultrasound probe are passed to an optimized slicing algorithm, which computes cross sections at arbitrary positions and orientations from the registered MRI dataset. The extracted MRI cross sections are finally fused with the region of interest from the ultrasound image. The system allows for the computation and visualization of slices at a near real-time rate. Primary tests of the system show an added value to the pure sonographic imaging. The system also allows for reconstructing volumetric (3D) ultrasonic data of the region of interest, and thus contributes to enhancing the diagnostic yield of midbrain sonography.

[Partial nucleotomy of the ovine disc as an in vivo model for disc degeneration].

PubMed

Guder, E; Hill, S; Kandziora, F; Schnake, K J

2009-01-01

The aim of this study was to develop a suitable animal model for the clinical situation of progressive disc degeneration after microsurgical nucleotomy. Twenty sheep underwent standardised partial anterolateral nucleotomy at lumbar segment 3/4. After randomisation, 10 animals were sacrificed after 12 weeks (group 1). The remainder was sacrificed after 48 weeks (group 2). For radiological examination X-rays, MRI and post-mortem CT scans were performed. Lumbar discs L 3/4 with adjacent subchondral trabecular bone were harvested and analysed macroscopically and histologically. An image-analysing computer program was used to measure histomorphometric indices of bone structure. 17 segments could be evaluated. After 12 weeks (group 1) histological and radiological degenerative disc changes were noted. After 48 weeks (group 2), radiological signs in MRI reached statistical significance. Furthermore, group 2 showed significantly more osteophyte formations in CT scans. Histomorphometric changes of the disc and the adjacent vertebral bone structure suggest a significant progressive degenerative remodelling. The facet joints did not show any osteoarthrosis after 48 weeks. Partial nucleotomy of the ovine lumbar disc leads to radiological and histological signs of disc degeneration similar to those seen in humans after microsurgical nucleotomy. The presented in vivo model may be useful to evaluate new orthopaedic treatment strategies.

The value of specific MRI features in the evaluation of suspected placental invasion.

PubMed

Lax, Allison; Prince, Martin R; Mennitt, Kevin W; Schwebach, J Reid; Budorick, Nancy E

2007-01-01

The objective of this study was to determine imaging features that may help predict the presence of placenta accreta, placenta increta or placenta percreta on prenatal MRI scanning. A retrospective review of the prenatal MR scans of 10 patients with a diagnosis of placenta accreta, placenta increta or placenta percreta made by pathologic and clinical reports and of 10 patients without placental invasion was performed. Two expert MRI readers were blinded to the patients' true diagnosis and were asked to score a total of 17 MRI features of the placenta and adjacent structures. The interrater reliability was assessed using kappa statistics. The features with a moderate kappa statistic or better (kappa > .40) were then compared with the true diagnosis for each observer. Seven of the scored features had an interobserver reliability of kappa > .40: placenta previa (kappa = .83); abnormal uterine bulging (kappa = .48); intraplacental hemorrhage (kappa = .51); heterogeneity of signal intensity on T2-weighted (T2W) imaging (kappa = .61); the presence of dark intraplacental bands on T2W imaging (kappa = .53); increased placental thickness (kappa = .69); and visualization of the myometrium beneath the placenta on T2W imaging (kappa = .44). Using Fisher's two-sided exact test, there was a statistically significant difference between the proportion of patients with placental invasion and those without placental invasion for three of the features: abnormal uterine bulging (Rater 1, P = .005; Rater 2, P = .011); heterogeneity of T2W imaging signal intensity (Rater 1, P = .006; Rater 2, P = .010); and presence of dark intraplacental bands on T2W imaging (Rater 1, P = .003; Rater 2, P = .033). MRI can be a useful adjunct to ultrasound in diagnosing placenta accreta prenatally. Three features that are seen on MRI in patients with placental invasion appear to be useful for diagnosis: uterine bulging; heterogeneous signal intensity within the placenta; and the presence of dark intraplacental bands on T2W imaging.

Cost-effectiveness of EOB-MRI for Hepatocellular Carcinoma in Japan.

PubMed

Nishie, Akihiro; Goshima, Satoshi; Haradome, Hiroki; Hatano, Etsuro; Imai, Yasuharu; Kudo, Masatoshi; Matsuda, Masanori; Motosugi, Utaroh; Saitoh, Satoshi; Yoshimitsu, Kengo; Crawford, Bruce; Kruger, Eliza; Ball, Graeme; Honda, Hiroshi

2017-04-01

The objective of the study was to evaluate the cost-effectiveness of gadoxetic acid-enhanced magnetic resonance imaging (EOB-MRI) in the diagnosis and treatment of hepatocellular carcinoma (HCC) in Japan compared with extracellular contrast media-enhanced MRI (ECCM-MRI) and contrast media-enhanced computed tomography (CE-CT) scanning. A 6-stage Markov model was developed to estimate lifetime direct costs and clinical outcomes associated with EOB-MRI. Diagnostic sensitivity and specificity, along with clinical data on HCC survival, recurrence, treatment patterns, costs, and health state utility values, were derived from predominantly Japanese publications. Parameters unavailable from publications were estimated in a Delphi panel of Japanese clinical experts who also confirmed the structure and overall approach of the model. Sensitivity analyses, including one-way, probabilistic, and scenario analyses, were conducted to account for uncertainty in the results. Over a lifetime horizon, EOB-MRI was associated with lower direct costs (¥2,174,869) and generated a greater number of quality-adjusted life years (QALYs) (9.502) than either ECCM-MRI (¥2,365,421, 9.303 QALYs) or CE-CT (¥2,482,608, 9.215 QALYs). EOB-MRI was superior to the other diagnostic strategies considered, and this finding was robust over sensitivity and scenario analyses. A majority of the direct costs associated with HCC in Japan were found to be costs of treatment. The model results revealed the superior cost-effectiveness of the EOB-MRI diagnostic strategy compared with ECCM-MRI and CE-CT. EOB-MRI could be the first-choice imaging modality for medical care of HCC among patients with hepatitis or liver cirrhosis in Japan. Widespread implementation of EOB-MRI could reduce health care expenditures, particularly downstream treatment costs, associated with HCC. Copyright © 2017 Elsevier HS Journals, Inc. All rights reserved.

Triple dose of gadolinium-DTPA and delayed MRI in patients with benign multiple sclerosis.

PubMed Central

Filippi, M; Capra, R; Campi, A; Colombo, B; Prandini, F; Marcianò, N; Gasparotti, R; Comi, G

1996-01-01

OBJECTIVES--To evaluate whether a triple dose of gadolinium-DTPA (Gd-DTPA) or delayed MRI increase the number, size, and conspicuousness of enhancing lesions in patients with benign multiple sclerosis. METHODS--T1 weighted brain MRI was carried out on 20 patients with benign multiple sclerosis (expanded disability status scale < 3 with a disease duration > 10 years) in two sessions. In the first session, one scan was obtained before and two scans five to seven minutes and 20-30 minutes after the injection of 0.1 mmol/kg Gd-DTPA (standard dose). In the second session, six to 24 hours later, the same procedure was repeated with 0.3 mmol/kg Gd-DTPA (triple dose). RESULTS--Nine enhancing lesions were found in seven patients (35%) using the standard dose of Gd-DTPA. The numbers of enhancing lesions increased to 13 (P = 0.03) and the number of patients with such lesions to eight (40%) on the delayed standard dose scans. On the early triple dose scans, we found 19 enhancing lesions in 10 patients (50%). The number of enhancing lesions was significantly higher (P = 0.01) than that obtained with the early standard dose. The number of enhancing lesions was 18 and the number of "active" patients 11 (55%) on the delayed triple dose scans. The enhancing areas increased progressively from the early standard dose scans to the delayed triple dose scans. The contrast ratios of the lesions detected in early standard dose scans was lower than those of lesions present in the early (P = 0.01) and delayed (P = 0.04) triple dose scans. CONCLUSIONS--More enhancing lesions were detected in patients with benign multiple sclerosis with both delay of MRI and the use of triple dose of Gd-DTPA suggesting that the amount of inflammation in the lesions of such patients is mild and heterogeneous. Images PMID:8778257

Influence of amplitude-related perfusion parameters in the parotid glands by non-fat-saturated dynamic contrast-enhanced magnetic resonance imaging.

PubMed

Chiu, Su-Chin; Cheng, Cheng-Chieh; Chang, Hing-Chiu; Chung, Hsiao-Wen; Chiu, Hui-Chu; Liu, Yi-Jui; Hsu, Hsian-He; Juan, Chun-Jung

2016-04-01

To verify whether quantification of parotid perfusion is affected by fat signals on non-fat-saturated (NFS) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and whether the influence of fat is reduced with fat saturation (FS). This study consisted of three parts. First, a retrospective study analyzed DCE-MRI data previously acquired on different patients using NFS (n = 18) or FS (n = 18) scans. Second, a phantom study simulated the signal enhancements in the presence of gadolinium contrast agent at six concentrations and three fat contents. Finally, a prospective study recruited nine healthy volunteers to investigate the influence of fat suppression on perfusion quantification on the same subjects. Parotid perfusion parameters were derived from NFS and FS DCE-MRI data using both pharmacokinetic model analysis and semiquantitative parametric analysis. T tests and linear regression analysis were used for statistical analysis with correction for multiple comparisons. NFS scans showed lower amplitude-related parameters, including parameter A, peak enhancement (PE), and slope than FS scans in the patients (all with P < 0.0167). The relative signal enhancement in the phantoms was proportional to the dose of contrast agent and was lower in NFS scans than in FS scans. The volunteer study showed lower parameter A (6.75 ± 2.38 a.u.), PE (42.12% ± 14.87%), and slope (1.43% ± 0.54% s(-1)) in NFS scans as compared to 17.63 ± 8.56 a.u., 104.22% ± 25.15%, and 9.68% ± 1.67% s(-1), respectively, in FS scans (all with P < 0.005). These amplitude-related parameters were negatively associated with the fat content in NFS scans only (all with P < 0.05). On NFS DCE-MRI, quantification of parotid perfusion is adversely affected by the presence of fat signals for all amplitude-related parameters. The influence could be reduced on FS scans.

Low back pain: an assessment using positional MRI and MDT.

PubMed

Hedberg, Karen; Alexander, Lyndsay A; Cooper, Kay; Hancock, Elizabeth; Ross, Jenny; Smith, Francis W

2013-04-01

Current guidelines advise against the use of routine imaging for low back pain. Positional MRI can provide enhanced assessment of the lumbar spine in functionally loaded positions which are often relevant to the presenting clinical symptoms. The purpose of this case report is to highlight the use of positional MRI in the assessment and classification of a subject with low back pain. A low back pain subject underwent a Mechanical Diagnosis and Therapy (MDT) assessment and positional MRI scan of the lumbar spine. The MDT assessment classified the subject as "other" since the subjective history indicated a possible posterior derangement whilst the objective assessment indicated a possible anterior derangement. Positional MRI scanning in flexed, upright and extended sitting postures confirmed the MDT assessment findings to reveal a dynamic spinal stenosis which reduced in flexion and increased in extension. Copyright © 2012 Elsevier Ltd. All rights reserved.

Assessment of pulmonary structure-function relationships in young children and adolescents with cystic fibrosis by multivolume proton-MRI and CT.

PubMed

Pennati, Francesca; Roach, David J; Clancy, John P; Brody, Alan S; Fleck, Robert J; Aliverti, Andrea; Woods, Jason C

2018-02-19

Lung disease is the most frequent cause of morbidity and mortality in patients with cystic fibrosis (CF), and there is a shortage of sensitive biomarkers able to regionally monitor disease progression and to assess early responses to therapy. To determine the feasibility of noncontrast-enhanced multivolume MRI, which assesses intensity changes between expiratory and inspiratory breath-hold images, to detect and quantify regional ventilation abnormalities in CF lung disease, with a focus on the structure-function relationship. Retrospective. Twenty-nine subjects, including healthy young children (n = 9, 7-37 months), healthy adolescents (n = 4, 14-22 years), young children with CF lung disease (n = 10, 7-47 months), and adolescents with CF lung disease (n = 6, 8-18 years) were studied. 3D spoiled gradient-recalled sequence at 1.5T. Subjects were scanned during breath-hold at functional residual capacity (FRC) and total lung capacity (TLC) through noncontrast-enhanced MRI and CT. Expiratory-inspiratory differences in MR signal-intensity (Δ 1 H-MRI) and CT-density (ΔHU) were computed to estimate regional ventilation. MR and CT images were also evaluated using a CF-specific scoring system. Quadratic regression, Spearman's correlation, one-way analysis of variance (ANOVA). Δ 1 H-MRI maps were sensitive to ventilation heterogeneity related to gravity dependence in healthy lung and to ventilation impairment in CF lung disease. A high correlation was found between MRI and CT ventilation maps (R 2  = 0.79, P < 0.001). Globally, Δ 1 H-MRI and ΔHU decrease with increasing morphological score (respectively, R 2  = 0.56, P < 0.001 and R 2  = 0.31, P < 0.001). Locally, Δ 1 H-MRI was higher in healthy regions (median 15%) compared to regions with bronchiectasis, air trapping, consolidation, and to segments fed by airways with bronchial wall thickening (P < 0.001). Multivolume noncontrast-enhanced MRI, as a nonionizing imaging modality that can be used on nearly any MRI scanner without specialized equipment or gaseous tracers, may be particularly valuable in CF care, providing a new imaging biomarker to detect early alterations in regional lung structure-function. 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018. © 2018 International Society for Magnetic Resonance in Medicine.

Ultrashort Echo-Time Magnetic Resonance Imaging Is a Sensitive Method for the Evaluation of Early Cystic Fibrosis Lung Disease

PubMed Central

Roach, David J.; Crémillieux, Yannick; Fleck, Robert J.; Brody, Alan S.; Serai, Suraj D.; Szczesniak, Rhonda D.; Kerlakian, Stephanie; Clancy, John P.

2016-01-01

Rationale: Recent advancements that have been made in magnetic resonance imaging (MRI) improve our ability to assess pulmonary structure and function in patients with cystic fibrosis (CF). A nonionizing imaging modality that can be used as a serial monitoring tool throughout life can positively affect patient care and outcomes. Objectives: To compare an ultrashort echo-time MRI method with computed tomography (CT) as a biomarker of lung structure abnormalities in young children with early CF lung disease. Methods: Eleven patients with CF (mean age, 31.8 ± 5.7 mo; median age, 33 mo; 7 male and 4 female) were imaged via CT and ultrashort echo-time MRI. Eleven healthy age-matched patients (mean age, 22.5 ± 10.2 mo; median age, 23 mo; 5 male and 6 female) were imaged via ultrashort echo-time MRI. CT scans of 13 additional patients obtained for clinical indications not affecting the heart or lungs and interpreted as normal provided a CT control group (mean age, 24.1 ± 11.7 mo; median age, 24 mo; 6 male and 7 female). Studies were scored by two experienced radiologists using a well-validated CF-specific scoring system for CF lung disease. Measurements and Main Results: Correlations between CT and ultrashort echo-time MRI scores of patients with CF were very strong, with P values ≤0.001 for bronchiectasis (r = 0.96) and overall score (r = 0.90), and moderately strong for bronchial wall thickening (r = 0.62, P = 0.043). MRI easily differentiated CF and control groups via a reader CF-specific scoring system. Conclusions: Ultrashort echo-time MRI detected structural lung disease in very young patients with CF and provided imaging data that correlated well with CT. By quantifying early CF lung disease without using ionizing radiation, ultrashort echo-time MRI appears well suited for pediatric patients requiring longitudinal imaging for clinical care or research studies. Clinical Trial registered with www.clinicaltrials.gov (NCT01832519). PMID:27551814

Heritability estimates on resting state fMRI data using ENIGMA analysis pipeline.

PubMed

Adhikari, Bhim M; Jahanshad, Neda; Shukla, Dinesh; Glahn, David C; Blangero, John; Reynolds, Richard C; Cox, Robert W; Fieremans, Els; Veraart, Jelle; Novikov, Dmitry S; Nichols, Thomas E; Hong, L Elliot; Thompson, Paul M; Kochunov, Peter

2018-01-01

Big data initiatives such as the Enhancing NeuroImaging Genetics through Meta-Analysis consortium (ENIGMA), combine data collected by independent studies worldwide to achieve more generalizable estimates of effect sizes and more reliable and reproducible outcomes. Such efforts require harmonized image analyses protocols to extract phenotypes consistently. This harmonization is particularly challenging for resting state fMRI due to the wide variability of acquisition protocols and scanner platforms; this leads to site-to-site variance in quality, resolution and temporal signal-to-noise ratio (tSNR). An effective harmonization should provide optimal measures for data of different qualities. We developed a multi-site rsfMRI analysis pipeline to allow research groups around the world to process rsfMRI scans in a harmonized way, to extract consistent and quantitative measurements of connectivity and to perform coordinated statistical tests. We used the single-modality ENIGMA rsfMRI preprocessing pipeline based on modelfree Marchenko-Pastur PCA based denoising to verify and replicate resting state network heritability estimates. We analyzed two independent cohorts, GOBS (Genetics of Brain Structure) and HCP (the Human Connectome Project), which collected data using conventional and connectomics oriented fMRI protocols, respectively. We used seed-based connectivity and dual-regression approaches to show that the rsfMRI signal is consistently heritable across twenty major functional network measures. Heritability values of 20-40% were observed across both cohorts.

Quantitative Comparison of 21 Protocols for Labeling Hippocampal Subfields and Parahippocampal Subregions in In Vivo MRI: Towards a Harmonized Segmentation Protocol

PubMed Central

Yushkevich, Paul A.; Amaral, Robert S. C.; Augustinack, Jean C.; Bender, Andrew R.; Bernstein, Jeffrey D.; Boccardi, Marina; Bocchetta, Martina; Burggren, Alison C.; Carr, Valerie A.; Chakravarty, M. Mallar; Chetelat, Gael; Daugherty, Ana M.; Davachi, Lila; Ding, Song-Lin; Ekstrom, Arne; Geerlings, Mirjam I.; Hassan, Abdul; Huang, Yushan; Iglesias, Eugenio; La Joie, Renaud; Kerchner, Geoffrey A.; LaRocque, Karen F.; Libby, Laura A.; Malykhin, Nikolai; Mueller, Susanne G.; Olsen, Rosanna K.; Palombo, Daniela J.; Parekh, Mansi B; Pluta, John B.; Preston, Alison R.; Pruessner, Jens C.; Ranganath, Charan; Raz, Naftali; Schlichting, Margaret L.; Schoemaker, Dorothee; Singh, Sachi; Stark, Craig E. L.; Suthana, Nanthia; Tompary, Alexa; Turowski, Marta M.; Van Leemput, Koen; Wagner, Anthony D.; Wang, Lei; Winterburn, Julie L.; Wisse, Laura E.M.; Yassa, Michael A.; Zeineh, Michael M.

2015-01-01

OBJECTIVE An increasing number of human in vivo magnetic resonance imaging (MRI) studies have focused on examining the structure and function of the subfields of the hippocampal formation (the dentate gyrus, CA fields 1–3, and the subiculum) and subregions of the parahippocampal gyrus (entorhinal, perirhinal, and parahippocampal cortices). The ability to interpret the results of such studies and to relate them to each other would be improved if a common standard existed for labeling hippocampal subfields and parahippocampal subregions. Currently, research groups label different subsets of structures and use different rules, landmarks, and cues to define their anatomical extents. This paper characterizes, both qualitatively and quantitatively, the variability in the existing manual segmentation protocols for labeling hippocampal and parahippocampal substructures in MRI, with the goal of guiding subsequent work on developing a harmonized substructure segmentation protocol. METHOD MRI scans of a single healthy adult human subject were acquired both at 3 Tesla and 7 Tesla. Representatives from 21 research groups applied their respective manual segmentation protocols to the MRI modalities of their choice. The resulting set of 21 segmentations was analyzed in a common anatomical space to quantify similarity and identify areas of agreement. RESULTS The differences between the 21 protocols include the region within which segmentation is performed, the set of anatomical labels used, and the extents of specific anatomical labels. The greatest overall disagreement among the protocols is at the CA1/subiculum boundary, and disagreement across all structures is greatest in the anterior portion of the hippocampal formation relative to the body and tail. CONCLUSIONS The combined examination of the 21 protocols in the same dataset suggests possible strategies towards developing a harmonized subfield segmentation protocol and facilitates comparison between published studies. PMID:25596463

Functional neuroimaging correlates of thinking flexibility and knowledge structure in memory: Exploring the relationships between clinical reasoning and diagnostic thinking.

PubMed

Durning, Steven J; Costanzo, Michelle E; Beckman, Thomas J; Artino, Anthony R; Roy, Michael J; van der Vleuten, Cees; Holmboe, Eric S; Lipner, Rebecca S; Schuwirth, Lambert

2016-06-01

Diagnostic reasoning involves the thinking steps up to and including arrival at a diagnosis. Dual process theory posits that a physician's thinking is based on both non-analytic or fast, subconscious thinking and analytic thinking that is slower, more conscious, effortful and characterized by comparing and contrasting alternatives. Expertise in clinical reasoning may relate to the two dimensions measured by the diagnostic thinking inventory (DTI): memory structure and flexibility in thinking. Explored the functional magnetic resonance imaging (fMRI) correlates of these two aspects of the DTI: memory structure and flexibility of thinking. Participants answered and reflected upon multiple-choice questions (MCQs) during fMRI. A DTI was completed shortly after the scan. The brain processes associated with the two dimensions of the DTI were correlated with fMRI phases - assessing flexibility in thinking during analytical clinical reasoning, memory structure during non-analytical clinical reasoning and the total DTI during both non-analytical and analytical reasoning in experienced physicians. Each DTI component was associated with distinct functional neuroanatomic activation patterns, particularly in the prefrontal cortex. Our findings support diagnostic thinking conceptual models and indicate mechanisms through which cognitive demands may induce functional adaptation within the prefrontal cortex. This provides additional objective validity evidence for the use of the DTI in medical education and practice settings.

Investigation of undersampling and reconstruction algorithm dependence on respiratory correlated 4D-MRI for online MR-guided radiation therapy

NASA Astrophysics Data System (ADS)

Mickevicius, Nikolai J.; Paulson, Eric S.

2017-04-01

The purpose of this work is to investigate the effects of undersampling and reconstruction algorithm on the total processing time and image quality of respiratory phase-resolved 4D MRI data. Specifically, the goal is to obtain quality 4D-MRI data with a combined acquisition and reconstruction time of five minutes or less, which we reasoned would be satisfactory for pre-treatment 4D-MRI in online MRI-gRT. A 3D stack-of-stars, self-navigated, 4D-MRI acquisition was used to scan three healthy volunteers at three image resolutions and two scan durations. The NUFFT, CG-SENSE, SPIRiT, and XD-GRASP reconstruction algorithms were used to reconstruct each dataset on a high performance reconstruction computer. The overall image quality, reconstruction time, artifact prevalence, and motion estimates were compared. The CG-SENSE and XD-GRASP reconstructions provided superior image quality over the other algorithms. The combination of a 3D SoS sequence and parallelized reconstruction algorithms using computing hardware more advanced than those typically seen on product MRI scanners, can result in acquisition and reconstruction of high quality respiratory correlated 4D-MRI images in less than five minutes.

MRI assessment of whole-brain structural changes in aging.

PubMed

Guo, Hui; Siu, William; D'Arcy, Ryan Cn; Black, Sandra E; Grajauskas, Lukas A; Singh, Sonia; Zhang, Yunting; Rockwood, Kenneth; Song, Xiaowei

2017-01-01

One of the central features of brain aging is the accumulation of multiple age-related structural changes, which occur heterogeneously in individuals and can have immediate or potential clinical consequences. Each of these deficits can coexist and interact, producing both independent and additive impacts on brain health. Many of the changes can be visualized using MRI. To collectively assess whole-brain structural changes, the MRI-based Brain Atrophy and Lesion Index (BALI) has been developed. In this study, we validate this whole-brain health assessment approach using several clinical MRI examinations. Data came from three independent studies: the Alzheimer's Disease Neuroimaging Initiative Phase II (n=950; women =47.9%; age =72.7±7.4 years); the National Alzheimer's Coordinating Center (n=722; women =55.1%; age =72.7±9.9 years); and the Tianjin Medical University General Hospital Research database on older adults (n=170; women =60.0%; age =62.9±9.3 years). The 3.0-Tesla MRI scans were evaluated using the BALI rating scheme on the basis of T1-weighted (T1WI), T2-weighted (T2WI), T2-weighted fluid-attenuated inversion recovery (T2-FLAIR), and T2*-weighted gradient-recalled echo (T2*GRE) images. Atrophy and lesion changes were commonly seen in each MRI test. The BALI scores based on different sequences were highly correlated (Spearman r 2 >0.69; P <0.00001). They were associated with age ( r 2 >0.29; P <0.00001) and differed by cognitive status ( χ 2 >26.48, P <0.00001). T2-FLAIR revealed a greater level of periventricular ( χ 2 =29.09) and deep white matter ( χ 2 =26.65, P <0.001) lesions than others, but missed revealing certain dilated perivascular spaces that were seen in T2WI ( P <0.001). Microhemorrhages occurred in 15.3% of the sample examined and were detected using only T2*GRE. The T1WI- and T2WI-based BALI evaluations consistently identified the burden of aging and dementia-related decline of structural brain health. Inclusion of additional MRI tests increased lesion differentiation. Further research is to integrate MRI tests for a clinical tool to aid the diagnosis and intervention of brain aging.

EU Directive 2004/40: field measurements of a 1.5 T clinical MR scanner.

PubMed

Riches, S F; Collins, D J; Scuffham, J W; Leach, M O

2007-06-01

The European Union (EU) Physical Agents (EMF) Directive [1] must be incorporated into UK law in 2008. The directive, which applies to employees working in MRI, sets legal exposure limits for two of the three types of EMF exposure employed in MRI; time-varying gradient fields and radiofrequency (RF) fields. Limits on the static field are currently not included but may be added at a later date. Conservative action values have been set for all three types of exposure including the static field. The absolute exposure limits will exclude staff from the scanner bore and adjacent areas during scanning, impacting on many clinical activities such as anaesthetic monitoring during sedated scans, paediatric scanning and interventional MRI. When the legislation comes into force, NHS Trusts, scanner companies and academic institutions will be required to show compliance with the law. We present results of initial measurements performed on a 1.5 T clinical MRI scanner. For the static field, the proposed action value is exceeded at 40 cm from the scanner bore and would be exceeded when positioning a patient for scanning. For the RF field, the action values were only exceeded within the bore at distances of 40 cm from the scanner ends during a very RF intensive sequence; MRI employees are unlikely to be in the bore during an acquisition. For the time-varying gradient fields the action values were exceeded 52 cm out from the mouth of the bore during two clinical sequences, and estimated current densities show the exposure limit to be exceeded at 40 cm for frequencies above 333 Hz. Limiting employees to distances greater than these from the scanner during acquisition will have a severe impact on the future use and development of MRI.

MRI of human hair.

PubMed

Mattle, Eveline; Weiger, Markus; Schmidig, Daniel; Boesiger, Peter; Fey, Michael

2009-06-01

Hair care for humans is a major world industry with specialised tools, chemicals and techniques. Studying the effect of hair care products has become a considerable field of research, and besides mechanical and optical testing numerous advanced analytical techniques have been employed in this area. In the present work, another means of studying the properties of hair is added by demonstrating the feasibility of magnetic resonance imaging (MRI) of the human hair. Established dedicated nuclear magnetic resonance microscopy hardware (solenoidal radiofrequency microcoils and planar field gradients) and methods (constant time imaging) were adapted to the specific needs of hair MRI. Images were produced at a spatial resolution high enough to resolve the inner structure of the hair, showing contrast between cortex and medulla. Quantitative evaluation of a scan series with different echo times provided a T*(2) value of 2.6 ms for the cortex and a water content of about 90% for hairs saturated with water. The demonstration of the feasibility of hair MRI potentially adds a new tool to the large variety of analytical methods used nowadays in the development of hair care products.

Development of Ferrite-Based Temperature Sensors for Magnetic Resonance Imaging: A Study of Cu1 -xZnxFe2O4

NASA Astrophysics Data System (ADS)

Alghamdi, N. A.; Hankiewicz, J. H.; Anderson, N. R.; Stupic, K. F.; Camley, R. E.; Przybylski, M.; Żukrowski, J.; Celinski, Z.

2018-05-01

We investigate the use of Cu1 -xZnxFe2O4 ferrites (0.60

Three-Dimensional Magnetic Resonance Imaging Quantification of Glenoid Bone Loss Is Equivalent to 3-Dimensional Computed Tomography Quantification: Cadaveric Study.

PubMed

Yanke, Adam B; Shin, Jason J; Pearson, Ian; Bach, Bernard R; Romeo, Anthony A; Cole, Brian J; Verma, Nikhil N

2017-04-01

To assess the ability of 3-dimensional (3D) magnetic resonance imaging (MRI, 1.5 and 3 tesla [T]) to quantify glenoid bone loss in a cadaveric model compared with the current gold standard, 3D computed tomography (CT). Six cadaveric shoulders were used to create a bone loss model, leaving the surrounding soft tissues intact. The anteroposterior (AP) dimension of the glenoid was measured at the glenoid equator and after soft tissue layer closure the specimen underwent scanning (CT, 1.5-T MRI, and 3-T MRI) with the following methods (0%, 10%, and 25% defect by area). Raw axial data from the scans were segmented using manual mask manipulation for bone and reconstructed using Mimics software to obtain a 3D en face glenoid view. Using calibrated Digital Imaging and Communications in Medicine images, the diameter of the glenoid at the equator and the area of the glenoid defect was measured on all imaging modalities. In specimens with 10% or 25% defects, no difference was detected between imaging modalities when comparing the measured defect size (10% defect P = .27, 25% defect P = .73). All 3 modalities demonstrated a strong correlation with the actual defect size (CT, ρ = .97; 1.5-T MRI, ρ = .93; 3-T MRI, ρ = .92, P < .0001). When looking at the absolute difference between the actual and measured defect area, no significance was noted between imaging modalities (10% defect P = .34, 25% defect P = .47). The error of 3-T 3D MRI increased with increasing defect size (P = .02). Both 1.5- and 3-T-based 3D MRI reconstructions of glenoid bone loss correlate with measurements from 3D CT scan data and actual defect size in a cadaveric model. Regardless of imaging modality, the error in bone loss measurement tends to increase with increased defect size. Use of 3D MRI in the setting of shoulder instability could obviate the need for CT scans. The goal of our work was to develop a reproducible method of determining glenoid bone loss from 3D MRI data and hence eliminate the need for CT scans in this setting. This will lead to decreased cost of care as well as decreased radiation exposure to patients. The long-term goal is a fully automated system that is as approachable for clinicians as current 3D CT technology. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Spiral MRI on a 9.4T Vertical-bore Superconducting Magnet Using Unshielded and Self-shielded Gradient Coils

PubMed Central

Kodama, Nao; Setoi, Ayana; Kose, Katsumi

2018-01-01

Spiral MRI sequences were developed for a 9.4T vertical standard bore (54 mm) superconducting magnet using unshielded and self-shielded gradient coils. Clear spiral images with 64-shot scan were obtained with the self-shielded gradient coil, but severe shading artifacts were observed for the spiral-scan images acquired with the unshielded gradient coil. This shading artifact was successfully corrected with a phase-correction technique using reference scans that we developed based on eddy current field measurements. We therefore concluded that spiral imaging sequences can be installed even for unshielded gradient coils if phase corrections are performed using the reference scans. PMID:28367906

Spiral MRI on a 9.4T Vertical-bore Superconducting Magnet Using Unshielded and Self-shielded Gradient Coils.

PubMed

Kodama, Nao; Setoi, Ayana; Kose, Katsumi

2018-04-10

Spiral MRI sequences were developed for a 9.4T vertical standard bore (54 mm) superconducting magnet using unshielded and self-shielded gradient coils. Clear spiral images with 64-shot scan were obtained with the self-shielded gradient coil, but severe shading artifacts were observed for the spiral-scan images acquired with the unshielded gradient coil. This shading artifact was successfully corrected with a phase-correction technique using reference scans that we developed based on eddy current field measurements. We therefore concluded that spiral imaging sequences can be installed even for unshielded gradient coils if phase corrections are performed using the reference scans.

Clinical Muscle Testing Compared with Whole-Body Magnetic Resonance Imaging in Facio-scapulo-humeral Muscular Dystrophy.

PubMed

Regula, J U; Jestaedt, L; Jende, F; Bartsch, A; Meinck, H-M; Weber, M-A

2016-12-01

The objective of this study was to evaluate the clinical usefulness of whole-body magnetic resonance imaging (MRI) in facio-scapulo-humeral muscular dystrophy (FSHD). In 20 patients with genetically proven FSHD1, we prospectively assessed muscular involvement and correlated the results of semi-quantitative manual muscle testing and other parameters such as disease duration, creatine kinase (CK) levels and repeat length of the D4Z4 locus with whole-body MRI. Clinical muscle testing revealed the trapezius, pectoralis and infraspinatus as the most severely affected muscles in the shoulder, and the knee flexors and gluteus medius in the hip girdle. MRI revealed the trapezius and serratus anterior muscles in the shoulder, and the hamstrings and adductor muscles in the hip girdle, as the most severely affected muscle groups. Overall, degrees of fatty degeneration on MRI scans correlated significantly with clinical weakness. Moreover, we could detect clear affection of the trunk muscles. Corresponding to earlier reports, asymmetric involvement was frequent in both clinical examination and MRI scoring. Moreover, MRI revealed inhomogeneous muscle degeneration in a considerable proportion of both, muscles and patients. Both clinical and MRI scores significantly correlated to disease duration, but not to fragment size or CK levels. Fatty degeneration in whole-body MRI correlates well to clinical muscle testing of the extremities but gives more information on deeper or trunk muscles. It shows structural changes in muscular disorders and may become an excellent tool for assessment of muscle involvement and follow-up studies.

A fast multiparameter MRI approach for acute stroke assessment on a 3T clinical scanner: preliminary results in a non-human primate model with transient ischemic occlusion.

PubMed

Zhang, Xiaodong; Tong, Frank; Li, Chun-Xia; Yan, Yumei; Nair, Govind; Nagaoka, Tsukasa; Tanaka, Yoji; Zola, Stuart; Howell, Leonard

2014-04-01

Many MRI parameters have been explored and demonstrated the capability or potential to evaluate acute stroke injury, providing anatomical, microstructural, functional, or neurochemical information for diagnostic purposes and therapeutic development. However, the application of multiparameter MRI approach is hindered in clinic due to the very limited time window after stroke insult. Parallel imaging technique can accelerate MRI data acquisition dramatically and has been incorporated in modern clinical scanners and increasingly applied for various diagnostic purposes. In the present study, a fast multiparameter MRI approach including structural T1-weighted imaging (T1W), T2-weighted imaging (T2W), diffusion tensor imaging (DTI), T2-mapping, proton magnetic resonance spectroscopy, cerebral blood flow (CBF), and magnetization transfer (MT) imaging, was implemented and optimized for assessing acute stroke injury on a 3T clinical scanner. A macaque model of transient ischemic stroke induced by a minimal interventional approach was utilized for evaluating the multiparameter MRI approach. The preliminary results indicate the surgical procedure successfully induced ischemic occlusion in the cortex and/or subcortex in adult macaque monkeys (n=4). Application of parallel imaging technique substantially reduced the scanning duration of most MRI data acquisitions, allowing for fast and repeated evaluation of acute stroke injury. Hence, the use of the multiparameter MRI approach with up to five quantitative measures can provide significant advantages in preclinical or clinical studies of stroke disease.

Image fusion pitfalls for cranial radiosurgery

PubMed Central

Jonker, Benjamin P.

2013-01-01

Stereotactic radiosurgery requires imaging to define both the stereotactic space in which the treatment is delivered and the target itself. Image fusion is the process of using rotation and translation to bring a second image set into alignment with the first image set. This allows the potential concurrent use of multiple image sets to define the target and stereotactic space. While a single magnetic resonance imaging (MRI) sequence alone can be used for delineation of the target and fiducials, there may be significant advantages to using additional imaging sets including other MRI sequences, computed tomography (CT) scans, and advanced imaging sets such as catheter-based angiography, diffusor tension imaging-based fiber tracking and positon emission tomography in order to more accurately define the target and surrounding critical structures. Stereotactic space is usually defined by detection of fiducials on the stereotactic head frame or mask system. Unfortunately MRI sequences are susceptible to geometric distortion, whereas CT scans do not face this problem (although they have poorer resolution of the target in most cases). Thus image fusion can allow the definition of stereotactic space to proceed from the geometrically accurate CT images at the same time as using MRI to define the target. The use of image fusion is associated with risk of error introduced by inaccuracies of the fusion process, as well as workflow changes that if not properly accounted for can mislead the treating clinician. The purpose of this review is to describe the uses of image fusion in stereotactic radiosurgery as well as its potential pitfalls. PMID:23682338

The role of the left inferior parietal lobule in second language learning: An intensive language training fMRI study.

PubMed

Barbeau, Elise B; Chai, Xiaoqian J; Chen, Jen-Kai; Soles, Jennika; Berken, Jonathan; Baum, Shari; Watkins, Kate E; Klein, Denise

2017-04-01

Research to date suggests that second language acquisition results in functional and structural changes in the bilingual brain, however, in what way and how quickly these changes occur remains unclear. To address these questions, we studied fourteen English-speaking monolingual adults enrolled in a 12-week intensive French language-training program in Montreal. Using functional MRI, we investigated the neural changes associated with new language acquisition. The participants were scanned before the start of the immersion program and at the end of the 12 weeks. The fMRI scan aimed to investigate the brain regions recruited in a sentence reading task both in English, their first language (L1), and in French, their second language (L2). For the L1, fMRI patterns did not change from Time 1 to Time 2, while for the L2, the brain response changed between Time 1 and Time 2 in language-related areas. Of note, for the L2, there was higher activation at Time 2 compared to Time 1 in the left inferior parietal lobule (IPL) including the supramarginal gyrus. At Time 2 this higher activation in the IPL correlated with faster L2 reading speed. Moreover, higher activation in the left IPL at Time 1 predicted improvement in L2 reading speed from Time 1 to Time 2. Our results suggest that learning-induced plasticity occurred as early as 12 weeks into immersive second-language training, and that the IPL appears to play a special role in language learning. Copyright © 2016 Elsevier Ltd. All rights reserved.

MRI-conditional pacemakers: current perspectives.

PubMed

Ferreira, António M; Costa, Francisco; Tralhão, António; Marques, Hugo; Cardim, Nuno; Adragão, Pedro

2014-01-01

Use of both magnetic resonance imaging (MRI) and pacing devices has undergone remarkable growth in recent years, and it is estimated that the majority of patients with pacemakers will need an MRI during their lifetime. These investigations will generally be denied due to the potentially dangerous interactions between cardiac devices and the magnetic fields and radio frequency energy used in MRI. Despite the increasing reports of uneventful scanning in selected patients with conventional pacemakers under close surveillance, MRI is still contraindicated in those circumstances and cannot be considered a routine procedure. These limitations prompted a series of modifications in generator and lead engineering, designed to minimize interactions that could compromise device function and patient safety. The resulting MRI-conditional pacemakers were first introduced in 2008 and the clinical experience gathered so far supports their safety in the MRI environment if certain conditions are fulfilled. With this technology, new questions and controversies arise regarding patient selection, clinical impact, and cost-effectiveness. In this review, we discuss the potential risks of MRI in patients with electronic cardiac devices and present updated information regarding the features of MRI-conditional pacemakers and the clinical experience with currently available models. Finally, we provide some guidance on how to scan patients who have these devices and discuss future directions in the field.

Clinical and anatomical guidelines in pelvic cancer contouring for radiotherapy treatment planning.

PubMed

Portaluri, Maurizio; Bambace, Santa; Perez, Celeste; Giuliano, Giuseppe; Angone, Grazia; Scialpi, Michele; Pili, Giorgio; Didonna, Vittorio; Alloro, Emira

2004-08-01

Many observations on potential inadequate coverage of tumour volume at risk in advanced cervical cancer (CC) when conventional radiation fields are used, have further substantiated by investigators using MRI, CT or lymphangiographic imaging. This work tries to obtain three dimensional margins by observing enlarged nodes in CT scans in order to improve pelvic nodal chains clinical target volumes (CTVs) drawing, and by looking for corroborative evidence in the literature for a better delineation of tumour CTV. Eleven consecutive patients (seven males, four females, mean age 62 years, range 43-78) with CT diagnosis of nodal involvement caused by pathologically proved carcinoma of the cervix (n = 2), carcinoma of the rectum (n = 2), carcinoma of the prostate (n = 2), non-Hodgkin lymphoma (n = 2), Hodgkin lymphoma (n = 1), carcinoma of the penis (n = 1) and carcinoma of the corpus uteri (n = 1) were retrospectively reviewed. Sixty CT scans with 67 enlarged pelvic nodes were reviewed in order to record the more proximal structures (muscle, bone, vessels, cutis or subcutis and other organs) to each enlarged node or group of nodes according to the four surfaces (anterior, lateral, posterior and medial) in a clockwise direction. A summary of the observations of each nodal chain and the number of occurrences of every marginal structure on axial CT slices is presented. Finally, simple guidelines are proposed. Tumour CTV should be based on individual tumour anatomy-mainly for lateral beams as it results from sagittal T2 weighted MRI images. Boundaries of pelvic nodes CTVs can be derived from observations of enlarged lymph nodes in CT scans.

Assessment of the cervical spine denticulate ligament using MRI volumetric sequence: Comparison between 1.5 Tesla and 3.0 Tesla.

PubMed

Seragioli, Rafael; Simao, Marcelo Novelino; Simao, Gustavo Novelino; Herrero, Carlos Fernando P S; Nogueira-Barbosa, Marcello H

2018-03-01

Denticulate ligaments (DLs) are pial extensions on each side of the spinal cord, comprising about 20 to 21 pairs of fibrous structures connecting the dura mater to the spinal cord. These ligaments are significant anatomical landmarks in the surgical approach to intradural structures. To our knowledge, there is no previous study on the detection of DLs using MRI. After IRB approval, we retrospectively evaluated 116 consecutive MRI scans of the cervical spine, using the volumetric sequence 3D COSMIC, 65 and 51 studies with 1.5T and 3.0T respectively. We did not include trauma and tumor cases. Two independent radiologists assessed the detection of cervical spine DLs independently and blinded for each cervical vertebral level. We compared the frequency of detection of these ligaments in 1.5 Tesla and 3.0 Tesla MRI using Fisher exact test considering P<0.05 as significant. We evaluated interobserver agreement with Kappa coefficient. We observed high detection frequency of the cervical spine DLs using both 1.5T (70 to 91%) and 3.0T (68 to 98%). We found no statistically significant difference in the detection frequency of ligaments between the 1.5T and 3.0T MRI in all vertebral levels. Using 3.0T, radiologists identified ligaments better in higher vertebral levels than for lower cervical levels (P=0.0003). Interobserver agreement on the identification of DL was poor both for 1.5T (k=0.3744; CI 95% 0.28-0.46) and 3.0T (k=0.3044; CI 95% 0.18-0.42) MRI. Radiologists identified most of the cervical DLs using volumetric MRI acquisition. Our results suggest 1.5T and 3.0T MRI performed similarly in the detection of DLs. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Functional and Structural Correlates of Motor Speed in the Cerebellar Anterior Lobe

PubMed Central

Wenzel, Uwe; Taubert, Marco; Ragert, Patrick; Krug, Jürgen; Villringer, Arno

2014-01-01

In athletics, motor performance is determined by different abilities such as technique, endurance, strength and speed. Based on animal studies, motor speed is thought to be encoded in the basal ganglia, sensorimotor cortex and the cerebellum. The question arises whether there is a unique structural feature in the human brain, which allows “power athletes” to perform a simple foot movement significantly faster than “endurance athletes”. We acquired structural and functional brain imaging data from 32 track-and-field athletes. The study comprised of 16 “power athletes” requiring high speed foot movements (sprinters, jumpers, throwers) and 16 endurance athletes (distance runners) which in contrast do not require as high speed foot movements. Functional magnetic resonance imaging (fMRI) was used to identify speed specific regions of interest in the brain during fast and slow foot movements. Anatomical MRI scans were performed to assess structural grey matter volume differences between athletes groups (voxel based morphometry). We tested maximum movement velocity of plantarflexion (PF-Vmax) and acquired electromyographical activity of the lateral and medial gastrocnemius muscle. Behaviourally, a significant difference between the two groups of athletes was noted in PF-Vmax and fMRI indicates that fast plantarflexions are accompanied by increased activity in the cerebellar anterior lobe. The same region indicates increased grey matter volume for the power athletes compared to the endurance counterparts. Our results suggest that speed-specific neuro-functional and -structural differences exist between power and endurance athletes in the peripheral and central nervous system. PMID:24800742

Language comprehension in nonspeaking children with severe cerebral palsy: Neuroanatomical substrate?

PubMed

Geytenbeek, Joke J; Oostrom, Kim J; Harlaar, Laurike; Becher, Jules G; Knol, Dirk L; Barkhof, Frederik; Pinto, Pedro S; Vermeulen, R Jeroen

2015-09-01

To identify relations between brain abnormalities and spoken language comprehension, MRI characteristics of 80 nonspeaking children with severe CP were examined. MRI scans were analysed for patterns of brain abnormalities and scored for specific MRI measures: white matter (WM) areas; size of lateral ventricles, WM abnormality/reduction, cysts, subarachnoid space, corpus callosum thinning and grey matter (GM) areas; cortical GM abnormalities, thalamus, putamen, globus pallidus and nucleus caudatus and cerebellar abnormalities. Language comprehension was assessed with a new validated instrument (C-BiLLT). MRI scans of 35 children were classified as a basal ganglia necrosis (BGN) pattern, with damage to central GM areas; in 60% of these children damage to WM areas was also found. MRI scans of 13 children were classified as periventricular leukomalacia (PVL) with little concomitant damage to central GM areas, 13 as malformations and 19 as miscellaneous. Language comprehension was best in children with BGN, followed by malformations and miscellaneous, and was poorest in PVL. Linear regression modelling per pattern group (malformations excluded), with MRI measures as independent variables, revealed that corpus callosum thinning in BGN and parieto-occipital WM reduction in PVL were the most important explanatory factors for poor language comprehension. No MRI measures explained outcomes in language comprehension in the miscellaneous group. Comprehension of spoken language differs between MRI patterns of severe CP. In children with BGN and PVL differences in language comprehension performance is attributed to damage in the WM areas. Language comprehension was most affected in children with WM lesions in the subcortical and then periventricular areas, most characteristic for children with PVL. Copyright © 2015 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

Automatic delineation of brain regions on MRI and PET images from the pig.

PubMed

Villadsen, Jonas; Hansen, Hanne D; Jørgensen, Louise M; Keller, Sune H; Andersen, Flemming L; Petersen, Ida N; Knudsen, Gitte M; Svarer, Claus

2018-01-15

The increasing use of the pig as a research model in neuroimaging requires standardized processing tools. For example, extraction of regional dynamic time series from brain PET images requires parcellation procedures that benefit from being automated. Manual inter-modality spatial normalization to a MRI atlas is operator-dependent, time-consuming, and can be inaccurate with lack of cortical radiotracer binding or skull uptake. A parcellated PET template that allows for automatic spatial normalization to PET images of any radiotracer. MRI and [ 11 C]Cimbi-36 PET scans obtained in sixteen pigs made the basis for the atlas. The high resolution MRI scans allowed for creation of an accurately averaged MRI template. By aligning the within-subject PET scans to their MRI counterparts, an averaged PET template was created in the same space. We developed an automatic procedure for spatial normalization of the averaged PET template to new PET images and hereby facilitated transfer of the atlas regional parcellation. Evaluation of the automatic spatial normalization procedure found the median voxel displacement to be 0.22±0.08mm using the MRI template with individual MRI images and 0.92±0.26mm using the PET template with individual [ 11 C]Cimbi-36 PET images. We tested the automatic procedure by assessing eleven PET radiotracers with different kinetics and spatial distributions by using perfusion-weighted images of early PET time frames. We here present an automatic procedure for accurate and reproducible spatial normalization and parcellation of pig PET images of any radiotracer with reasonable blood-brain barrier penetration. Copyright © 2017 Elsevier B.V. All rights reserved.

Less head motion during MRI under task than resting-state conditions.

PubMed

Huijbers, Willem; Van Dijk, Koene R A; Boenniger, Meta M; Stirnberg, Rüdiger; Breteler, Monique M B

2017-02-15

Head motion reduces data quality of neuroimaging data. In three functional magnetic resonance imaging (MRI) experiments we demonstrate that people make less head movements under task than resting-state conditions. In Experiment 1, we observed less head motion during a memory encoding task than during the resting-state condition. In Experiment 2, using publicly shared data from the UCLA Consortium for Neuropsychiatric Phenomics LA5c Study, we again found less head motion during several active task conditions than during a resting-state condition, although some task conditions also showed comparable motion. In the healthy controls, we found more head motion in men than in women and more motion with increasing age. When comparing clinical groups, we found that patients with a clinical diagnosis of bipolar disorder, or schizophrenia, move more compared to healthy controls or patients with ADHD. Both these experiments had a fixed acquisition order across participants, and we could not rule out that a first or last scan during a session might be particularly prone to more head motion. Therefore, we conducted Experiment 3, in which we collected several task and resting-state fMRI runs with an acquisition order counter-balanced. The results of Experiment 3 show again less head motion during several task conditions than during rest. Together these experiments demonstrate that small head motions occur during MRI even with careful instruction to remain still and fixation with foam pillows, but that head motion is lower when participants are engaged in a cognitive task. These finding may inform the choice of functional runs when studying difficult-to-scan populations, such as children or certain patient populations. Our findings also indicate that differences in head motion complicate direct comparisons of measures of functional neuronal networks between task and resting-state fMRI because of potential differences in data quality. In practice, a task to reduce head motion might be especially useful when acquiring structural MRI data such as T1/T2-weighted and diffusion MRI in research and clinical settings. Copyright © 2016 Elsevier Inc. All rights reserved.

H.M.'s contributions to neuroscience: a review and autopsy studies.

PubMed

Augustinack, Jean C; van der Kouwe, André J W; Salat, David H; Benner, Thomas; Stevens, Allison A; Annese, Jacopo; Fischl, Bruce; Frosch, Matthew P; Corkin, Suzanne

2014-11-01

H.M., Henry Molaison, was one of the world's most famous amnesic patients. His amnesia was caused by an experimental brain operation, bilateral medial temporal lobe resection, carried out in 1953 to relieve intractable epilepsy. He died on December 2, 2008, and that night we conducted a wide variety of in situ MRI scans in a 3 T scanner at the Massachusetts General Hospital (Mass General) Athinoula A. Martinos Center for Biomedical Imaging. For the in situ experiments, we acquired a full set of standard clinical scans, 1 mm isotropic anatomical scans, and multiple averages of 440 μm isotropic anatomical scans. The next morning, H.M.'s body was transported to the Mass General Morgue for autopsy. The photographs taken at that time provided the first documentation of H.M.'s lesions in his physical brain. After tissue fixation, we obtained ex vivo structural data at ultra-high resolution using 3 T and 7 T magnets. For the ex vivo acquisitions, the highest resolution images were 210 μm isotropic. Based on the MRI data, the anatomical areas removed during H.M.'s experimental operation were the medial temporopolar cortex, piriform cortex, virtually all of the entorhinal cortex, most of the perirhinal cortex and subiculum, the amygdala (except parts of the dorsal-most nuclei-central and medial), anterior half of the hippocampus, and the dentate gyrus (posterior head and body). The posterior parahippocampal gyrus and medial temporal stem were partially damaged. Spared medial temporal lobe tissue included the dorsal-most amygdala, the hippocampal-amygdalo-transition-area, ∼2 cm of the tail of the hippocampus, a small part of perirhinal cortex, a small portion of medial hippocampal tissue, and ∼2 cm of posterior parahippocampal gyrus. H.M.'s impact on the field of memory has been remarkable, and his contributions to neuroscience continue with a unique dataset that includes in vivo, in situ, and ex vivo high-resolution MRI. Copyright © 2014 Wiley Periodicals, Inc.

[Modern Management of Pancoast Tumour].

PubMed

Marra, Alessandro

2018-06-01

Pancoast or superior pulmonary sulcus tumour is a subset of lung carcinoma that invades the structures of the thoracic inlet - first ribs, distal roots of the brachial plexus, stellate ganglion, vertebrae, and subclavian vessels. The first symptom is usually shoulder pain; consequently, most patients are initially treated for osteoarthritis. Late diagnosis is common. Success of therapy depends on an accurate staging: standard imaging with CT scan of the chest, PET-CT scan, brain MRI are needed to rule out distant metastases, endobronchial ultrasound-guided needle biopsy (EBUS-TBNA) or mediastinoscopy are mandatory for reliable nodal staging. An MRI of the thoracic inlet allows to clearly define the boundaries of local invasion. Modern management of Pancoast tumour includes induction concurrent chemoradiotherapy followed by surgical resection. As compared with historical series treated by preoperative radiation, a trimodally approach did enhance complete resection rates and perhaps long-term survival - from about 30% 5-year survival rate to 60% in R0-resected patients. In patients who have unresectable but non-metastatic Pancoast tumours and appropriate performance status, definitive concurrent chemoradiotherapy and radiotherapy are recommended options. Georg Thieme Verlag KG Stuttgart · New York.

Clinical safety of the ProMRI pacemaker system in patients subjected to head and lower lumbar 1.5-T magnetic resonance imaging scanning conditions.

PubMed

Bailey, William M; Rosenthal, Lawrence; Fananapazir, Lameh; Gleva, Marye; Mazur, Alexander; Rinaldi, C A; Kypta, Alexander; Merkely, Béla; Woodard, Pamela K

2015-06-01

Permanent cardiac pacemakers have historically been considered a contraindication to magnetic resonance imaging (MRI). The purpose of the ProMRI/ProMRI AFFIRM Study, which was a multicenter, prospective, single-arm, nonrandomized study, was to evaluate the clinical safety of the Biotronik ProMRI Pacemaker System under specific MRI conditions. The ProMRI Study (in the United States) and the ProMRI AFFIRM study (outside the United States) with identical design enrolled 272 patients with stable baseline pacing indices implanted with an Entovis or Evia pacemaker (DR-T or SR-T) and Setrox or Safio 53-cm or 60-cm lead. Device interrogation was performed at enrollment, pre-MRI and post-MRI scan, and 1 and 3 months post-MRI. End-points were (1) freedom from MRI- and pacing system-related serious adverse device effects (SADEs) through 1 month post-MRI, (2) freedom from atrial and ventricular MRI-induced pacing threshold increase (>0.5 V), and (3) freedom from P- and R-wave amplitude attenuation (<50%), or P wave <1.5 mV, or R wave <5.0 mV at 1 month post-MRI. Two hundred twenty-six patients completed the MRI and 1-month post-MRI follow-up. No adverse events related to the implanted system and the MRI procedure occurred, resulting in an SADE-free rate of 100.0% (229/229, P <.001). Freedom from atrial and ventricular pacing threshold increase was 99.0% (189/191, P = .003) and 100% (217/217, P <.001), respectively. Freedom from P- and R- wave amplitude attenuation was 99.4% (167/168, P <.001) and 99.5% (193/194, P <.001), respectively. The results of the ProMRI/ProMRI AFFIRM studies demonstrate the clinical safety and efficacy of the ProMRI pacemaker system in patients subjected to head and lower lumbar MRI conditions. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

The NAIMS cooperative pilot project: Design, implementation and future directions.

PubMed

Oh, Jiwon; Bakshi, Rohit; Calabresi, Peter A; Crainiceanu, Ciprian; Henry, Roland G; Nair, Govind; Papinutto, Nico; Constable, R Todd; Reich, Daniel S; Pelletier, Daniel; Rooney, William; Schwartz, Daniel; Tagge, Ian; Shinohara, Russell T; Simon, Jack H; Sicotte, Nancy L

2017-10-01

The North American Imaging in Multiple Sclerosis (NAIMS) Cooperative represents a network of 27 academic centers focused on accelerating the pace of magnetic resonance imaging (MRI) research in multiple sclerosis (MS) through idea exchange and collaboration. Recently, NAIMS completed its first project evaluating the feasibility of implementation and reproducibility of quantitative MRI measures derived from scanning a single MS patient using a high-resolution 3T protocol at seven sites. The results showed the feasibility of utilizing advanced quantitative MRI measures in multicenter studies and demonstrated the importance of careful standardization of scanning protocols, central image processing, and strategies to account for inter-site variability.

Altered spontaneous brain activity in MRI-negative refractory temporal lobe epilepsy patients with major depressive disorder: A resting-state fMRI study.

PubMed

Zhu, Xi; He, Zhongqiong; Luo, Cheng; Qiu, Xiangmiao; He, Shixu; Peng, Anjiao; Zhang, Lin; Chen, Lei

2018-03-15

To investigate alterations in spontaneous brain activity in MRI-negative refractory temporal lobe epilepsy patients with major depressive disorder using resting-state functional magnetic resonance imaging (RS-fMRI). Eighteen MRI-negative refractory temporal lobe epilepsy patients with major depressive disorder (PDD), 17 MRI-negative refractory temporal lobe epilepsy patients without major depressive disorder (nPDD), and 21 matched healthy controls (HC) were recruited from West China Hospital of SiChuan University from April 2016 to June 2017. The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) and 17-item Hamilton Depression Rating Scale were employed to confirm the diagnosis of major depressive disorder and assess the severity of depression. All participants underwent RS-fMRI scans using a 3.0T MRI system. MRI data were compared and analyzed using the amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) to measure spontaneous brain activity. These two methods were both used to evaluate spontaneous cerebral activity. The PDD group showed significantly altered spontaneous brain activity in the bilateral mesial prefrontal cortex, precuneus, angular gyrus, right parahippocampal gyrus, and right temporal pole. Meanwhile, compared with HC, the nPDD group demonstrated altered spontaneous brain activity in the temporal neocortex but no changes in mesial temporal structures. The PDD group showed regional brain activity alterations in the prefrontal-limbic system and dysfunction of the default mode network. The underlying pathophysiology of PDD may be provided for further studies. Copyright © 2018 Elsevier B.V. All rights reserved.

Study of the development of fetal baboon brain using magnetic resonance imaging at 3 Tesla

PubMed Central

Liu, Feng; Garland, Marianne; Duan, Yunsuo; Stark, Raymond I.; Xu, Dongrong; Dong, Zhengchao; Bansal, Ravi; Peterson, Bradley S.; Kangarlu, Alayar

2008-01-01

Direct observational data on the development of the brains of human and nonhuman primates is on remarkably scant, and most of our understanding of primate brain development is extrapolated from findings in rodent models. Magnetic resonance imaging (MRI) is a promising tool for the noninvasive, longitudinal study of the developing primate brain. We devised a protocol to scan pregnant baboons serially at 3 T for up to 3 h per session. Seven baboons were scanned 1–6 times, beginning as early as 56 days post-conceptional age, and as late as 185 days (term ~185 days). Successful scanning of the fetal baboon required careful animal preparation and anesthesia, in addition to optimization of the scanning protocol. We successfully acquired maps of relaxation times (T1 and T2) and high-resolution anatomical images of the brains of fetal baboons at multiple time points during the course of gestation. These images demonstrated the convergence of gray and white matter contrast near term, and furthermore demonstrated that the loss of contrast at that age is a consequence of the continuous change in relaxation times during fetal brain development. These data furthermore demonstrate that maps of relaxation times have clear advantages over the relaxation time weighted images for the tracking of the changes in brain structure during fetal development. This protocol for in utero MRI of fetal baboon brains will help to advance the use of nonhuman primate models to study fetal brain development longitudinally. PMID:18155925

Cost-effectiveness Analysis for Technology Acquisition.

PubMed

Chakravarty, A; Naware, S S

2008-01-01

In a developing country with limited resources, it is important to utilize the total cost visibility approach over the entire life-cycle of the technology and then analyse alternative options for acquiring technology. The present study analysed cost-effectiveness of an "In-house" magnetic resonance imaging (MRI) scan facility of a large service hospital against outsourcing possibilities. Cost per unit scan was calculated by operating costing method and break-even volume was calculated. Then life-cycle cost analysis was performed to enable total cost visibility of the MRI scan in both "In-house" and "outsourcing of facility" configuration. Finally, cost-effectiveness analysis was performed to identify the more acceptable decision option. Total cost for performing unit MRI scan was found to be Rs 3,875 for scans without contrast and Rs 4,129 with contrast. On life-cycle cost analysis, net present value (NPV) of the "In-house" configuration was found to be Rs-(4,09,06,265) while that of "outsourcing of facility" configuration was Rs-(5,70,23,315). Subsequently, cost-effectiveness analysis across eight Figures of Merit showed the "In-house" facility to be the more acceptable option for the system. Every decision for acquiring high-end technology must be subjected to life-cycle cost analysis.

Reconstruction of 7T-Like Images From 3T MRI

PubMed Central

Bahrami, Khosro; Shi, Feng; Zong, Xiaopeng; Shin, Hae Won; An, Hongyu

2016-01-01

In the recent MRI scanning, ultra-high-field (7T) MR imaging provides higher resolution and better tissue contrast compared to routine 3T MRI, which may help in more accurate and early brain diseases diagnosis. However, currently, 7T MRI scanners are more expensive and less available at clinical and research centers. These motivate us to propose a method for the reconstruction of images close to the quality of 7T MRI, called 7T-like images, from 3T MRI, to improve the quality in terms of resolution and contrast. By doing so, the post-processing tasks, such as tissue segmentation, can be done more accurately and brain tissues details can be seen with higher resolution and contrast. To do this, we have acquired a unique dataset which includes paired 3T and 7T images scanned from same subjects, and then propose a hierarchical reconstruction based on group sparsity in a novel multi-level Canonical Correlation Analysis (CCA) space, to improve the quality of 3T MR image to be 7T-like MRI. First, overlapping patches are extracted from the input 3T MR image. Then, by extracting the most similar patches from all the aligned 3T and 7T images in the training set, the paired 3T and 7T dictionaries are constructed for each patch. It is worth noting that, for the training, we use pairs of 3T and 7T MR images from each training subject. Then, we propose multi-level CCA to map the paired 3T and 7T patch sets to a common space to increase their correlations. In such space, each input 3T MRI patch is sparsely represented by the 3T dictionary and then the obtained sparse coefficients are used together with the corresponding 7T dictionary to reconstruct the 7T-like patch. Also, to have the structural consistency between adjacent patches, the group sparsity is employed. This reconstruction is performed with changing patch sizes in a hierarchical framework. Experiments have been done using 13 subjects with both 3T and 7T MR images. The results show that our method outperforms previous methods and is able to recover better structural details. Also, to place our proposed method in a medical application context, we evaluated the influence of post-processing methods such as brain tissue segmentation on the reconstructed 7T-like MR images. Results show that our 7T-like images lead to higher accuracy in segmentation of white matter (WM), gray matter (GM), cerebrospinal fluid (CSF), and skull, compared to segmentation of 3T MR images. PMID:27046894

Statistical model of laminar structure for atlas-based segmentation of the fetal brain from in utero MR images

NASA Astrophysics Data System (ADS)

Habas, Piotr A.; Kim, Kio; Chandramohan, Dharshan; Rousseau, Francois; Glenn, Orit A.; Studholme, Colin

2009-02-01

Recent advances in MR and image analysis allow for reconstruction of high-resolution 3D images from clinical in utero scans of the human fetal brain. Automated segmentation of tissue types from MR images (MRI) is a key step in the quantitative analysis of brain development. Conventional atlas-based methods for adult brain segmentation are limited in their ability to accurately delineate complex structures of developing tissues from fetal MRI. In this paper, we formulate a novel geometric representation of the fetal brain aimed at capturing the laminar structure of developing anatomy. The proposed model uses a depth-based encoding of tissue occurrence within the fetal brain and provides an additional anatomical constraint in a form of a laminar prior that can be incorporated into conventional atlas-based EM segmentation. Validation experiments are performed using clinical in utero scans of 5 fetal subjects at gestational ages ranging from 20.5 to 22.5 weeks. Experimental results are evaluated against reference manual segmentations and quantified in terms of Dice similarity coefficient (DSC). The study demonstrates that the use of laminar depth-encoded tissue priors improves both the overall accuracy and precision of fetal brain segmentation. Particular refinement is observed in regions of the parietal and occipital lobes where the DSC index is improved from 0.81 to 0.82 for cortical grey matter, from 0.71 to 0.73 for the germinal matrix, and from 0.81 to 0.87 for white matter.

Dynamic changes in network activations characterize early learning of a natural language.

PubMed

Plante, Elena; Patterson, Dianne; Dailey, Natalie S; Kyle, R Almyrde; Fridriksson, Julius

2014-09-01

Those who are initially exposed to an unfamiliar language have difficulty separating running speech into individual words, but over time will recognize both words and the grammatical structure of the language. Behavioral studies have used artificial languages to demonstrate that humans are sensitive to distributional information in language input, and can use this information to discover the structure of that language. This is done without direct instruction and learning occurs over the course of minutes rather than days or months. Moreover, learners may attend to different aspects of the language input as their own learning progresses. Here, we examine processing associated with the early stages of exposure to a natural language, using fMRI. Listeners were exposed to an unfamiliar language (Icelandic) while undergoing four consecutive fMRI scans. The Icelandic stimuli were constrained in ways known to produce rapid learning of aspects of language structure. After approximately 4 min of exposure to the Icelandic stimuli, participants began to differentiate between correct and incorrect sentences at above chance levels, with significant improvement between the first and last scan. An independent component analysis of the imaging data revealed four task-related components, two of which were associated with behavioral performance early in the experiment, and two with performance later in the experiment. This outcome suggests dynamic changes occur in the recruitment of neural resources even within the initial period of exposure to an unfamiliar natural language. Copyright © 2014 Elsevier Ltd. All rights reserved.

Resting state functional MRI reveals abnormal network connectivity in Neurofibromatosis 1

PubMed Central

Tomson, S.N.; Schreiner, M.; Narayan, M.; Rosser, Tena; Enrique, Nicole; Silva, Alcino J.; Allen, G.I.; Bookheimer, S.Y.; Bearden, C.E.

2015-01-01

Neurofibromatosis type I (NF1) is a genetic disorder caused by mutations in the neurofibromin 1 gene at locus 17q11.2. Individuals with NF1 have an increased incidence of learning disabilities, attention deficits and autism spectrum disorders. As a single gene disorder, NF1 represents a valuable model for understanding gene-brain-behavior relationships. While mouse models have elucidated molecular and cellular mechanisms underlying learning deficits associated with this mutation, little is known about functional brain architecture in human subjects with NF1. To address this question, we used resting state functional connectivity MRI (rs-fcMRI) to elucidate the intrinsic network structure of 30 NF1 participants compared with 30 healthy demographically matched controls during an eyes-open rs-fcMRI scan. Novel statistical methods were employed to quantify differences in local connectivity (edge strength) and modularity structure, in combination with traditional global graph theory applications. Our findings suggest that individuals with NF1 have reduced anterior-posterior connectivity, weaker bilateral edges, and altered modularity clustering relative to healthy controls. Further, edge strength and modular clustering indices were correlated with IQ and internalizing symptoms. These findings suggest that Ras signaling disruption may lead to abnormal functional brain connectivity; further investigation into the functional consequences of these alterations in both humans and in animal models is warranted. PMID:26304096

Discrete pre-processing step effects in registration-based pipelines, a preliminary volumetric study on T1-weighted images

PubMed Central

2017-01-01

Pre-processing MRI scans prior to performing volumetric analyses is common practice in MRI studies. As pre-processing steps adjust the voxel intensities, the space in which the scan exists, and the amount of data in the scan, it is possible that the steps have an effect on the volumetric output. To date, studies have compared between and not within pipelines, and so the impact of each step is unknown. This study aims to quantify the effects of pre-processing steps on volumetric measures in T1-weighted scans within a single pipeline. It was our hypothesis that pre-processing steps would significantly impact ROI volume estimations. One hundred fifteen participants from the OASIS dataset were used, where each participant contributed three scans. All scans were then pre-processed using a step-wise pipeline. Bilateral hippocampus, putamen, and middle temporal gyrus volume estimations were assessed following each successive step, and all data were processed by the same pipeline 5 times. Repeated-measures analyses tested for a main effects of pipeline step, scan-rescan (for MRI scanner consistency) and repeated pipeline runs (for algorithmic consistency). A main effect of pipeline step was detected, and interestingly an interaction between pipeline step and ROI exists. No effect for either scan-rescan or repeated pipeline run was detected. We then supply a correction for noise in the data resulting from pre-processing. PMID:29023597

Diagnostic yield of a routine magnetic resonance imaging in tinnitus and clinical relevance of the anterior inferior cerebellar artery loops.

PubMed

Hoekstra, Carlijn E L; Prijs, Vera F; van Zanten, Gijsbert A

2015-02-01

To assess the diagnostic yield of a routine magnetic resonance imaging (MRI) scan in patients with (unilateral) chronic tinnitus, to define the frequency of incidental findings, and to assess the clinical relevance of potentially found anterior inferior cerebellar artery (AICA) loops. Retrospective cohort study. Tertiary Tinnitus Care Group at the University Medical Center Utrecht. Three hundred twenty-one patients with chronic tinnitus. Routine diagnostic magnetic resonance imaging (MRI) and diagnostic auditory brainstem responses (ABR) when an AICA loop was found. Relationship between abnormalities on MRI and tinnitus. In 138 patients (45%), an abnormality on the MRI scan was described. In only 7 patients (2.2%), the abnormality probably related to the patient's tinnitus. Results were not significantly better in patients with unilateral tinnitus (abnormalities in 3.2%). Incidental findings, not related to the tinnitus, were found in 41% of the patients. In 70 patients (23%), an AICA loop was found in the internal auditory canal. No significant relationships were found between the presence of an AICA loop and the side of the tinnitus, abnormalities on the ABR or complaints specific to nerve compression syndrome. A routine MRI is of little or no value in patients with tinnitus with persistent complaints. Anterior inferior cerebellar artery loops are often encountered on an MRI scan but rarely relate to the tinnitus and should thus be considered incidental findings. It is advised to only perform an MRI when on clinical grounds a specific etiology with tinnitus as the symptom seems probable.

Sticking our neck out: is magnetic resonance imaging needed to clear an obtunded patient's cervical spine?

PubMed

Satahoo, Shevonne S; Davis, James S; Garcia, George D; Alsafran, Salman; Pandya, Reeni K; Richie, Cheryl D; Habib, Fahim; Rivas, Luis; Namias, Nicholas; Schulman, Carl I

2014-03-01

Evaluating the cervical spine in the obtunded trauma patient is a subject fraught with controversy. Some authors assert that a negative computed tomography (CT) scan is sufficient. Others argue that CT alone misses occult unstable injuries, and magnetic resonance imaging (MRI) will alter treatment. This study examines the data in an urban, county trauma center to determine if a negative cervical spine CT scan is sufficient to clear the obtunded trauma patient. Records of all consecutive patients admitted to a level 1 trauma center from January 2000 to December 2011 were retrospectively analyzed. Patients directly admitted to the intensive care unit with a Glasgow Coma Scale score ≤13, contemporaneous CT and MRI, and a negative CT reading were included. The results of the cervical spine MRI were analyzed. A total of 309 patients had both CT and MRI, 107 (35%) of whom had negative CTs. Mean time between CT and MRI was 16 d. Of those patients, seven (7%) had positive acute traumatic findings on MRI. Findings included ligamentous injury, subluxation, and fracture. However, only two of these patients required surgical intervention. None had unstable injuries. In the obtunded trauma patient with a negative cervical spine CT, obtaining an MRI does not appear to significantly alter management, and no unstable injuries were missed on CT scan. This should be taken into consideration given the current efforts at cost-containment in the health care system. It is one of the larger studies published to date. Copyright © 2014 Elsevier Inc. All rights reserved.

Incidental magnetic resonance imaging signal changes in the extensor carpi radialis brevis origin are more common with age.

PubMed

van Leeuwen, Wouter F; Janssen, Stein J; Ring, David; Chen, Neal

2016-07-01

Patients with enthesopathy of the extensor carpi radialis brevis (ECRB) demonstrate signal changes on magnetic resonance imaging (MRI). It is likely that these MRI changes persist for many years or may be permanent, regardless of symptoms, and represent an estimation of disease prevalence. We tested the hypothesis that the prevalence of incidental signal changes in the ECRB origin increases with age. We searched MRI reports of 3374 patients who underwent an MRI scan, including the elbow, for signal changes in the ECRB origin. Medical records were reviewed for symptoms consistent with ECRB enthesopathy. Prevalences of incidental and symptomatic signal changes were calculated and stratified by age. We used multivariate logistic regression analysis to test whether age, sex, and race were independently associated with ECRB enthesopathy and calculated odds ratios. Signal changes in ECRB origin were identified on MRI scans of 369 of 3374 patients (11%) without a clinical suspicion of tennis elbow. The prevalence increased from 5.7% in patients aged between 18 and 30 years up to 16% in patients aged 71 years and older. Older age (odds ratio, 1.04; P <.001) was independently associated with the incidental finding of ECRB enthesopathy on elbow MRI scans. Increased MRI signal in the ECRB origin is common in symptomatic and in asymptomatic elbows. Our findings support the concept that ECRB enthesopathy is a highly prevalent, self-limited process that seems to affect a minimum of 1 in approximately every 7 people. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

SU-E-J-120: Comparing 4D CT Computed Ventilation to Lung Function Measured with Hyperpolarized Xenon-129 MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neal, B; Chen, Q

2015-06-15

Purpose: To correlate ventilation parameters computed from 4D CT to ventilation, profusion, and gas exchange measured with hyperpolarized Xenon-129 MRI for a set of lung cancer patients. Methods: Hyperpolarized Xe-129 MRI lung scans were acquired for lung cancer patients, before and after radiation therapy, measuring ventilation, perfusion, and gas exchange. In the standard clinical workflow, these patients also received 4D CT scans before treatment. Ventilation was computed from 4D CT using deformable image registration (DIR). All phases of the 4D CT scan were registered using a B-spline deformable registration. Ventilation at the voxel level was then computed for each phasemore » based on a Jacobian volume expansion metric, yielding phase sorted ventilation images. Ventilation based upon 4D CT and Xe-129 MRI were co-registered, allowing qualitative visual comparison and qualitative comparison via the Pearson correlation coefficient. Results: Analysis shows a weak correlation between hyperpolarized Xe-129 MRI and 4D CT DIR ventilation, with a Pearson correlation coefficient of 0.17 to 0.22. Further work will refine the DIR parameters to optimize the correlation. The weak correlation could be due to the limitations of 4D CT, registration algorithms, or the Xe-129 MRI imaging. Continued development will refine parameters to optimize correlation. Conclusion: Current analysis yields a minimal correlation between 4D CT DIR and Xe-129 MRI ventilation. Funding provided by the 2014 George Amorino Pilot Grant in Radiation Oncology at the University of Virginia.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang Jenghwa; Kowalski, Alex; Hou, Bob

The purpose of this work was to study the feasibility of incorporating functional magnetic resonance imaging (fMRI) information for intensity modulated radiotherapy (IMRT) treatment planning of brain tumors. Three glioma patients were retrospectively replanned for radiotherapy (RT) with additional fMRI information. The fMRI of each patient was acquired using a bilateral finger-tapping paradigm with a gradient echo EPI (Echo Planer Imaging) sequence. The fMRI data were processed using the Analysis of Functional Neuroimaging (AFNI) software package for determining activation volumes, and the volumes were fused with the simulation computed tomography (CT) scan. The actived pixels in left and right primarymore » motor cortexes (PMCs) were contoured as critical structures for IMRT planning. The goal of replanning was to minimize the RT dose to the activation volumes in the PMC regions, while maintaining a similar coverage to the planning target volume (PTV) and keeping critical structures within accepted dose tolerance. Dose-volume histograms of the treatment plans with and without considering the fMRI information were compared. Beam angles adjustment or additional beams were needed for 2 cases to meet the planning criteria. Mean dose to the contralateral and ipsilateral PMC was significantly reduced by 66% and 55%, respectively, for 1 patient. For the other 2 patients, mean dose to contralateral PMC region was lowered by 73% and 69%. In general, IMRT optimization can reduce the RT dose to the PMC regions without compromising the PTV coverage or sparing of other critical organs. In conclusion, it is feasible to incorporate the fMRI information into the RT treatment planning. IMRT planning allows a significant reduction in RT dose to the PMC regions, especially if the region does not lie within the PTV.« less

Assessing the kidney function parameters glomerular filtration rate and effective renal plasma flow with dynamic FDG-PET/MRI in healthy subjects.

PubMed

Geist, Barbara K; Baltzer, Pascal; Fueger, Barbara; Hamboeck, Martina; Nakuz, Thomas; Papp, Laszlo; Rasul, Sazan; Sundar, Lalith Kumar Shiyam; Hacker, Marcus; Staudenherz, Anton

2018-05-09

A method was developed to assess the kidney parameters glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) from 2-deoxy-2-[ 18 F]fluoro-D-glucose (FDG) concentration behavior in kidneys, measured with positron emission tomography (PET) scans. Twenty-four healthy adult subjects prospectively underwent dynamic simultaneous PET/magnetic resonance imaging (MRI) examination. Time activity curves (TACs) were obtained from the dynamic PET series, with the guidance of MR information. Patlak analysis was performed to determine the GFR, and based on integrals, ERPF was calculated. Results were compared to intra-individually obtained reference values determined from venous blood samples. Total kidney GFR and ERPF as estimated by dynamic PET/MRI were highly correlated to their reference values (r = 0.88/p < 0.0001 and r = 0.82/p < 0.0001, respectively) with no significant difference between their means. The study is a proof of concept that GFR and ERPF can be assessed with dynamic FDG PET/MRI scans in healthy kidneys. This has advantages for patients getting a routine scan, where additional examinations for kidney function estimation could be avoided. Further studies are required for transferring this PET/MRI method to PET/CT applications.

Open database of epileptic EEG with MRI and postoperational assessment of foci--a real world verification for the EEG inverse solutions.

PubMed

Zwoliński, Piotr; Roszkowski, Marcin; Zygierewicz, Jaroslaw; Haufe, Stefan; Nolte, Guido; Durka, Piotr J

2010-12-01

This paper introduces a freely accessible database http://eeg.pl/epi , containing 23 datasets from patients diagnosed with and operated on for drug-resistant epilepsy. This was collected as part of the clinical routine at the Warsaw Memorial Child Hospital. Each record contains (1) pre-surgical electroencephalography (EEG) recording (10-20 system) with inter-ictal discharges marked separately by an expert, (2) a full set of magnetic resonance imaging (MRI) scans for calculations of the realistic forward models, (3) structural placement of the epileptogenic zone, recognized by electrocorticography (ECoG) and post-surgical results, plotted on pre-surgical MRI scans in transverse, sagittal and coronal projections, (4) brief clinical description of each case. The main goal of this project is evaluation of possible improvements of localization of epileptic foci from the surface EEG recordings. These datasets offer a unique possibility for evaluating different EEG inverse solutions. We present preliminary results from a subset of these cases, including comparison of different schemes for the EEG inverse solution and preprocessing. We report also a finding which relates to the selective parametrization of single waveforms by multivariate matching pursuit, which is used in the preprocessing for the inverse solutions. It seems to offer a possibility of tracing the spatial evolution of seizures in time.

SU-G-JeP2-12: Quantification of 3D Geometric Distortion for 1.5T and 3T MRI Scanners Used for Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stowe, M; Gupta, N; Raterman, B

Purpose: To quantify the magnitude of geometric distortion for MRI scanners and provide recommendations for MRI imaging for radiation therapy Methods: A novel phantom, QUASAR MRID3D [Modus Medical Devices Inc.], was scanned to evaluate the level of 3D geometric distortion present in five MRI scanners used for radiation therapy in our department. The phantom was scanned using the body coil with 1mm image slice thickness to acquire 3D images of the phantom body. The phantom was aligned to its geometric center for each scan, and the field of view was set to visualize the entire phantom. The dependence of distortionmore » magnitude with distance from imaging isocenter and with magnetic field strength (1.5T and 3T) was investigated. Additionally, the characteristics of distortion for Siemens and GE machines were compared. The image distortion for each scanner was quantified in terms of mean, standard deviation (STD), maximum distortion, and skewness. Results: The 3T and 1.5T scans show a similar absolute distortion with a mean of 1.38mm (0.33mm STD) for 3T and 1.39mm (0.34mm STD) for 1.5T for a 100mm radius distance from isocenter. Some machines can have a distortion larger than 10mm at a distance of 200mm from the isocenter. The distortions are presented with plots of the x, y, and z directional components. Conclusion: The results indicate that quantification of MRI image distortion is crucial in radiation oncology for target and organ delineation and treatment planning. The magnitude of geometric distortion determines the margin needed for target contouring which is usually neglected in treatment planning process, especially for SRS/SBRT treatments. Understanding the 3D distribution of the MRI image distortion will improve the accuracy of target delineation and, hence, treatment efficacy. MRI imaging with proper patient alignment to the isocenter is vital to reducing the effects of MRI distortion in treatment planning.« less

Early postnatal myelin content estimate of white matter via T1w/T2w ratio

NASA Astrophysics Data System (ADS)

Lee, Kevin; Cherel, Marie; Budin, Francois; Gilmore, John; Zaldarriaga Consing, Kirsten; Rasmussen, Jerod; Wadhwa, Pathik D.; Entringer, Sonja; Glasser, Matthew F.; Van Essen, David C.; Buss, Claudia; Styner, Martin

2015-03-01

To develop and evaluate a novel processing framework for the relative quantification of myelin content in cerebral white matter (WM) regions from brain MRI data via a computed ratio of T1 to T2 weighted intensity values. We employed high resolution (1mm3 isotropic) T1 and T2 weighted MRI from 46 (28 male, 18 female) neonate subjects (typically developing controls) scanned on a Siemens Tim Trio 3T at UC Irvine. We developed a novel, yet relatively straightforward image processing framework for WM myelin content estimation based on earlier work by Glasser, et al. We first co-register the structural MRI data to correct for motion. Then, background areas are masked out via a joint T1w and T2 foreground mask computed. Raw T1w/T2w-ratios images are computed next. For purpose of calibration across subjects, we first coarsely segment the fat-rich facial regions via an atlas co-registration. Linear intensity rescaling based on median T1w/T2w-ratio values in those facial regions yields calibrated T1w/T2wratio images. Mean values in lobar regions are evaluated using standard statistical analysis to investigate their interaction with age at scan. Several lobes have strongly positive significant interactions of age at scan with the computed T1w/T2w-ratio. Most regions do not show sex effects. A few regions show no measurable effects of change in myelin content change within the first few weeks of postnatal development, such as cingulate and CC areas, which we attribute to sample size and measurement variability. We developed and evaluated a novel way to estimate white matter myelin content for use in studies of brain white matter development.

Functional activity of the sensorimotor cortex and cerebellum relates to cervical dystonia symptoms.

PubMed

Burciu, Roxana G; Hess, Christopher W; Coombes, Stephen A; Ofori, Edward; Shukla, Priyank; Chung, Jae Woo; McFarland, Nikolaus R; Wagle Shukla, Aparna; Okun, Michael S; Vaillancourt, David E

2017-09-01

Cervical dystonia (CD) is the most common type of focal dystonia, causing abnormal movements of the neck and head. In this study, we used noninvasive imaging to investigate the motor system of patients with CD and uncover the neural correlates of dystonic symptoms. Furthermore, we examined whether a commonly prescribed anticholinergic medication in CD has an effect on the dystonia-related brain abnormalities. Participants included 16 patients with CD and 16 healthy age-matched controls. We collected functional MRI scans during a force task previously shown to extensively engage the motor system, and diffusion and T1-weighted MRI scans from which we calculated free-water and brain tissue densities. The dystonia group was also scanned ca. 2 h after a 2-mg dose of trihexyphenidyl. Severity of dystonia was assessed pre- and post-drug using the Burke-Fahn-Marsden Dystonia Rating Scale. Motor-related activity in CD was altered relative to controls in the primary somatosensory cortex, cerebellum, dorsal premotor and posterior parietal cortices, and occipital cortex. Most importantly, a regression model showed that increased severity of symptoms was associated with decreased functional activity of the somatosensory cortex and increased activity of the cerebellum. Structural imaging measures did not differ between CD and controls. The single dose of trihexyphenidyl altered the fMRI signal in the somatosensory cortex but not in the cerebellum. Symptom severity was not significantly reduced post-treatment. Findings show widespread changes in functional brain activity in CD and most importantly that dystonic symptoms relate to disrupted activity in the somatosensory cortex and cerebellum. Hum Brain Mapp 38:4563-4573, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Psychological impact and acceptability of magnetic resonance imaging and X-ray mammography: the MARIBS Study

PubMed Central

Hutton, J; Walker, L G; Gilbert, F J; Evans, D G; Eeles, R; Kwan-Lim, G E; Thompson, D; Pointon, L J; Sharp, D M; Leach, M O

2011-01-01

Background: As part of the Magnetic Resonance Imaging for Breast Screening (MARIBS), Study women with a family history of breast cancer were assessed psychologically to determine the relative psychological impact and acceptability of annual screening using magnetic resonance imaging (MRI) and conventional X-ray mammography (XRM). Methods: Women were assessed psychologically at baseline (4 weeks before MRI and XRM), immediately before, and immediately after, both MRI and XRM, and at follow-up (6 weeks after the scans). Results: Overall, both procedures were found to be acceptable with high levels of satisfaction (MRI, 96.3% and XRM, 97.7% NS) and low levels of psychological morbidity throughout, particularly at 6-week follow-up. Low levels of self-reported distress were reported for both procedures (MRI, 13.5% and XRM, 7.8%), although MRI was more distressing (P=0.005). Similarly, higher anticipatory anxiety was reported before MRI than before XRM (P=0.003). Relative to XRM, MRI-related distress was more likely to persist at 6 weeks after the scans in the form of intrusive MRI-related thoughts (P=0.006) and total MRI-related distress (P=0.014). More women stated that they intended to return for XRM (96.3%) than for MRI (88% P<0.0005). These effects were most marked for the first year of screening, although they were also statistically significant in subsequent years. Conclusion: Given the proven benefits of MRI in screening for breast cancer in this population, these data point to the urgent need to provide timely information and support to women undergoing MRI. PMID:21326245

Psychological impact and acceptability of magnetic resonance imaging and X-ray mammography: the MARIBS Study.

PubMed

Hutton, J; Walker, L G; Gilbert, F J; Evans, D G; Eeles, R; Kwan-Lim, G E; Thompson, D; Pointon, L J; Sharp, D M; Leach, M O

2011-02-15

As part of the Magnetic Resonance Imaging for Breast Screening (MARIBS), Study women with a family history of breast cancer were assessed psychologically to determine the relative psychological impact and acceptability of annual screening using magnetic resonance imaging (MRI) and conventional X-ray mammography (XRM). Women were assessed psychologically at baseline (4 weeks before MRI and XRM), immediately before, and immediately after, both MRI and XRM, and at follow-up (6 weeks after the scans). Overall, both procedures were found to be acceptable with high levels of satisfaction (MRI, 96.3% and XRM, 97.7%; NS) and low levels of psychological morbidity throughout, particularly at 6-week follow-up. Low levels of self-reported distress were reported for both procedures (MRI, 13.5% and XRM, 7.8%), although MRI was more distressing (P=0.005). Similarly, higher anticipatory anxiety was reported before MRI than before XRM (P=0.003). Relative to XRM, MRI-related distress was more likely to persist at 6 weeks after the scans in the form of intrusive MRI-related thoughts (P=0.006) and total MRI-related distress (P=0.014). More women stated that they intended to return for XRM (96.3%) than for MRI (88%; P<0.0005). These effects were most marked for the first year of screening, although they were also statistically significant in subsequent years. Given the proven benefits of MRI in screening for breast cancer in this population, these data point to the urgent need to provide timely information and support to women undergoing MRI.

Characterization of task-free and task-performance brain states via functional connectome patterns.

PubMed

Zhang, Xin; Guo, Lei; Li, Xiang; Zhang, Tuo; Zhu, Dajiang; Li, Kaiming; Chen, Hanbo; Lv, Jinglei; Jin, Changfeng; Zhao, Qun; Li, Lingjiang; Liu, Tianming

2013-12-01

Both resting state fMRI (R-fMRI) and task-based fMRI (T-fMRI) have been widely used to study the functional activities of the human brain during task-free and task-performance periods, respectively. However, due to the difficulty in strictly controlling the participating subject's mental status and their cognitive behaviors during R-fMRI/T-fMRI scans, it has been challenging to ascertain whether or not an R-fMRI/T-fMRI scan truly reflects the participant's functional brain states during task-free/task-performance periods. This paper presents a novel computational approach to characterizing and differentiating the brain's functional status into task-free or task-performance states, by which the functional brain activities can be effectively understood and differentiated. Briefly, the brain's functional state is represented by a whole-brain quasi-stable connectome pattern (WQCP) of R-fMRI or T-fMRI data based on 358 consistent cortical landmarks across individuals, and then an effective sparse representation method was applied to learn the atomic connectome patterns (ACPs) of both task-free and task-performance states. Experimental results demonstrated that the learned ACPs for R-fMRI and T-fMRI datasets are substantially different, as expected. A certain portion of ACPs from R-fMRI and T-fMRI data were overlapped, suggesting some subjects with overlapping ACPs were not in the expected task-free/task-performance brain states. Besides, potential outliers in the T-fMRI dataset were further investigated via functional activation detections in different groups, and our results revealed unexpected task-performances of some subjects. This work offers novel insights into the functional architectures of the brain. Copyright © 2013 Elsevier B.V. All rights reserved.

Characterization of Task-free and Task-performance Brain States via Functional Connectome Patterns

PubMed Central

Zhang, Xin; Guo, Lei; Li, Xiang; Zhang, Tuo; Zhu, Dajiang; Li, Kaiming; Chen, Hanbo; Lv, Jinglei; Jin, Changfeng; Zhao, Qun; Li, Lingjiang; Liu, Tianming

2014-01-01

Both resting state fMRI (R-fMRI) and task-based fMRI (T-fMRI) have been widely used to study the functional activities of the human brain during task-free and task-performance periods, respectively. However, due to the difficulty in strictly controlling the participating subject's mental status and their cognitive behaviors during R-fMRI/T-fMRI scans, it has been challenging to ascertain whether or not an R-fMRI/T-fMRI scan truly reflects the participant's functional brain states during task-free/task-performance periods. This paper presents a novel computational approach to characterizing and differentiating the brain's functional status into task-free or task-performance states, by which the functional brain activities can be effectively understood and differentiated. Briefly, the brain's functional state is represented by a whole-brain quasi-stable connectome pattern (WQCP) of R-fMRI or T-fMRI data based on 358 consistent cortical landmarks across individuals, and then an effective sparse representation method was applied to learn the atomic connectome patterns (ACP) of both task-free and task-performance states. Experimental results demonstrated that the learned ACPs for R-fMRI and T-fMRI datasets are substantially different, as expected. A certain portion of ACPs from R-fMRI and T-fMRI data were overlapped, suggesting some subjects with overlapping ACPs were not in the expected task-free/task-performance brain states. Besides, potential outliers in the T-fMRI dataset were further investigated via functional activation detections in different groups, and our results revealed unexpected task-performances of some subjects. This work offers novel insights into the functional architectures of the brain. PMID:23938590

Surveillance imaging in children with malignant CNS tumors: low yield of spine MRI.

PubMed

Perreault, Sébastien; Lober, Robert M; Carret, Anne-Sophie; Zhang, Guohua; Hershon, Linda; Décarie, Jean-Claude; Vogel, Hannes; Yeom, Kristen W; Fisher, Paul G; Partap, Sonia

2014-02-01

Magnetic resonance imaging (MRI) is routinely obtained in patients with central nervous system (CNS) tumors, but few studies have been conducted to evaluate this practice. We assessed the benefits of surveillance MRI and more specifically spine MRI in a contemporary cohort. We evaluated MRI results of children diagnosed with CNS tumors from January 2000 to December 2011. Children with at least one surveillance MRI following the diagnosis of medulloblastoma (MB), atypical teratoid rhabdoid tumor (ATRT), pineoblastoma (PB), supratentorial primitive neuroectodermal tumor, supratentorial high-grade glioma (World Health Organization grade III-IV), CNS germ cell tumors or ependymoma were included. A total of 2,707 brain and 1,280 spine MRI scans were obtained in 258 patients. 97% of all relapses occurred in the brain and 3% were isolated to the spine. Relapse was identified in 226 (8%) brain and 48 (4%) spine MRI scans. The overall rate of detecting isolated spinal relapse was 9/1,000 and 7/1,000 for MB patients. MRI performed for PB showed the highest rate for detecting isolated spinal recurrence with 49/1,000. No initial isolated spinal relapse was identified in patients with glioma, supratentorial primitive neuroectodermal tumor and ATRT. Isolated spinal recurrences are infrequent in children with malignant CNS tumors and the yield of spine MRI is very low. Tailoring surveillance spine MRI to patients with higher spinal relapse risk such as PB, MB with metastatic disease and within 3 years of diagnosis could improve allocation of resources without compromising patient care.

A 1-minute full brain MR exam using a multicontrast EPI sequence.

PubMed

Skare, Stefan; Sprenger, Tim; Norbeck, Ola; Rydén, Henric; Blomberg, Lars; Avventi, Enrico; Engström, Mathias

2018-06-01

A new multicontrast echo-planar imaging (EPI)-based sequence is proposed for brain MRI, which can directly generate six MR contrasts (T 1 -FLAIR, T 2 -w, diffusion-weighted (DWI), apparent diffusion coefficient (ADC), T2*-w, T 2 -FLAIR) in 1 min with full brain coverage. This could enable clinical MR clinical screening in similar time as a conventional CT exam but with more soft-tissue information. Eleven sequence modules were created as dynamic building blocks for the sequence. Two EPI readout modules were reused throughout the sequence and were prepended by other modules to form the desired MR contrasts. Two scan protocols were optimized with scan times of 55-75 s. Motion experiments were carried out on two volunteers to investigate the robustness against head motion. Scans on patients were carried out and compared to conventional clinical images. The pulse sequence is found to be robust against motion given its single-shot nature of each contrast. For excessive out-of-plane head motion, the T 1 -FLAIR and T 2 -FLAIR contrasts suffer from incomplete inversion. Despite lower signal-to-noise ratio (SNR) and resolution, the 1-min multicontrast EPI data show promising correspondence with conventional diagnostic scans on patients. A 1 min multicontrast brain MRI scan based on EPI readouts has been presented in this feasibility study. Preliminary data show potential for clinical brain MRI use with minimal bore time for the patient. Such short examination time could be useful (e.g., for screening and acute stroke). The sequence may also help planning conventional brain MRI scans if run at the beginning of an examination. Magn Reson Med 79:3045-3054, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Modern Pacemaker and Implantable Cardioverter/Defibrillator Systems Can Be Magnetic Resonance Imaging Safe

PubMed Central

Roguin, Ariel; Zviman, Menekhem M.; Meininger, Glenn R.; Rodrigues, E. Rene; Dickfeld, Timm M.; Bluemke, David A.; Lardo, Albert; Berger, Ronald D.; Calkins, Hugh; Halperin, Henry R.

2011-01-01

Background MRI has unparalleled soft-tissue imaging capabilities. The presence of devices such as pacemakers and implantable cardioverter/defibrillators (ICDs), however, is historically considered a contraindication to MRI. These devices are now smaller, with less magnetic material and improved electromagnetic interference protection. Our aim was to determine whether these modern systems can be used in an MR environment. Methods and Results We tested in vitro and in vivo lead heating, device function, force acting on the device, and image distortion at 1.5 T. Clinical MR protocols and in vivo measurements yielded temperature changes <0.5°C. Older (manufactured before 2000) ICDs were damaged by the MR scans. Newer ICD systems and most pacemakers, however, were not. The maximal force acting on newer devices was <100 g. Modern (manufactured after 2000) ICD systems were implanted in dogs (n=18), and after 4 weeks, 3- to 4-hour MR scans were performed (n=15). No device dysfunction occurred. The images were of high quality with distortion dependent on the scan sequence and plane. Pacing threshold and intracardiac electrogram amplitude were unchanged over the 8 weeks, except in 1 animal that, after MRI, had a transient (<12 hours) capture failure. Pathological data of the scanned animals revealed very limited necrosis or fibrosis at the tip of the lead area, which was not different from controls (n=3) not subjected to MRI. Conclusions These data suggest that certain modern pacemaker and ICD systems may indeed be MRI safe. This may have major clinical implications for current imaging practices. PMID:15277324

Learning Computational Models of Video Memorability from fMRI Brain Imaging.

PubMed

Han, Junwei; Chen, Changyuan; Shao, Ling; Hu, Xintao; Han, Jungong; Liu, Tianming

2015-08-01

Generally, various visual media are unequally memorable by the human brain. This paper looks into a new direction of modeling the memorability of video clips and automatically predicting how memorable they are by learning from brain functional magnetic resonance imaging (fMRI). We propose a novel computational framework by integrating the power of low-level audiovisual features and brain activity decoding via fMRI. Initially, a user study experiment is performed to create a ground truth database for measuring video memorability and a set of effective low-level audiovisual features is examined in this database. Then, human subjects' brain fMRI data are obtained when they are watching the video clips. The fMRI-derived features that convey the brain activity of memorizing videos are extracted using a universal brain reference system. Finally, due to the fact that fMRI scanning is expensive and time-consuming, a computational model is learned on our benchmark dataset with the objective of maximizing the correlation between the low-level audiovisual features and the fMRI-derived features using joint subspace learning. The learned model can then automatically predict the memorability of videos without fMRI scans. Evaluations on publically available image and video databases demonstrate the effectiveness of the proposed framework.

Implementation of time-efficient adaptive sampling function design for improved undersampled MRI reconstruction

NASA Astrophysics Data System (ADS)

Choi, Jinhyeok; Kim, Hyeonjin

2016-12-01

To improve the efficacy of undersampled MRI, a method of designing adaptive sampling functions is proposed that is simple to implement on an MR scanner and yet effectively improves the performance of the sampling functions. An approximation of the energy distribution of an image (E-map) is estimated from highly undersampled k-space data acquired in a prescan and efficiently recycled in the main scan. An adaptive probability density function (PDF) is generated by combining the E-map with a modeled PDF. A set of candidate sampling functions are then prepared from the adaptive PDF, among which the one with maximum energy is selected as the final sampling function. To validate its computational efficiency, the proposed method was implemented on an MR scanner, and its robust performance in Fourier-transform (FT) MRI and compressed sensing (CS) MRI was tested by simulations and in a cherry tomato. The proposed method consistently outperforms the conventional modeled PDF approach for undersampling ratios of 0.2 or higher in both FT-MRI and CS-MRI. To fully benefit from undersampled MRI, it is preferable that the design of adaptive sampling functions be performed online immediately before the main scan. In this way, the proposed method may further improve the efficacy of the undersampled MRI.

Function Biomedical Informatics Research Network Recommendations for Prospective Multi-Center Functional Magnetic Resonance Imaging Studies

PubMed Central

Glover, Gary H.; Mueller, Bryon A.; Turner, Jessica A.; van Erp, Theo G.M.; Liu, Thomas T.; Greve, Douglas N.; Voyvodic, James T.; Rasmussen, Jerod; Brown, Gregory G.; Keator, David B.; Calhoun, Vince D.; Lee, Hyo Jong; Ford, Judith M.; Mathalon, Daniel H.; Diaz, Michele; O’Leary, Daniel S.; Gadde, Syam; Preda, Adrian; Lim, Kelvin O.; Wible, Cynthia G.; Stern, Hal S.; Belger, Aysenil; McCarthy, Gregory; Ozyurt, Burak; Potkin, Steven G.

2011-01-01

This report provides practical recommendations for the design and execution of Multi-Center functional Magnetic Resonance Imaging (MC-fMRI) studies based on the collective experience of the Function Biomedical Informatics Research Network (FBIRN). The paper was inspired by many requests from the fMRI community to FBIRN group members for advice on how to conduct MC-fMRI studies. The introduction briefly discusses the advantages and complexities of MC-fMRI studies. Prerequisites for MC-fMRI studies are addressed before delving into the practical aspects of carefully and efficiently setting up a MC-fMRI study. Practical multi-site aspects include: (1) establishing and verifying scan parameters including scanner types and magnetic fields, (2) establishing and monitoring of a scanner quality program, (3) developing task paradigms and scan session documentation, (4) establishing clinical and scanner training to ensure consistency over time, (5) developing means for uploading, storing, and monitoring of imaging and other data, (6) the use of a traveling fMRI expert and (7) collectively analyzing imaging data and disseminating results. We conclude that when MC-fMRI studies are organized well with careful attention to unification of hardware, software and procedural aspects, the process can be a highly effective means for accessing a desired participant demographics while accelerating scientific discovery. PMID:22314879

Vibration and Noise in Magnetic Resonance Imaging of the Vocal Tract: Differences between Whole-Body and Open-Air Devices.

PubMed

Přibil, Jiří; Přibilová, Anna; Frollo, Ivan

2018-04-05

This article compares open-air and whole-body magnetic resonance imaging (MRI) equipment working with a weak magnetic field as regards the methods of its generation, spectral properties of mechanical vibration and acoustic noise produced by gradient coils during the scanning process, and the measured noise intensity. These devices are used for non-invasive MRI reconstruction of the human vocal tract during phonation with simultaneous speech recording. In this case, the vibration and noise have negative influence on quality of speech signal. Two basic measurement experiments were performed within the paper: mapping sound pressure levels in the MRI device vicinity and picking up vibration and noise signals in the MRI scanning area. Spectral characteristics of these signals are then analyzed statistically and compared visually and numerically.

An implemented MRI program to eliminate radiation from the evaluation of pediatric appendicitis.

PubMed

Kulaylat, Afif N; Moore, Michael M; Engbrecht, Brett W; Brian, James M; Khaku, Aliasgher; Hollenbeak, Christopher S; Rocourt, Dorothy V; Hulse, Michael A; Olympia, Robert P; Santos, Mary C; Methratta, Sosamma T; Dillon, Peter W; Cilley, Robert E

2015-08-01

Recent efforts have been directed at reducing ionizing radiation delivered by CT scans to children in the evaluation of appendicitis. MRI has emerged as an alternative diagnostic modality. The clinical outcomes associated with MRI in this setting are not well-described. Review of a 30-month institutional experience with MRI as the primary diagnostic evaluation for suspected appendicitis (n=510). No intravenous contrast, oral contrast, or sedation was administered. Radiologic and clinical outcomes were abstracted. MRI diagnostic characteristics were: sensitivity 96.8% (95% CI: 92.1%-99.1%), specificity 97.4% (95% CI: 95.3-98.7), positive predictive value 92.4% (95% CI: 86.5-96.3), and negative predictive value 98.9% (95% CI: 97.3%-99.7%). Radiologic time parameters included: median time from request to scan, 71 minutes (IQR: 51-102), imaging duration, 11 minutes (IQR: 8-17), and request to interpretation, 2.0 hours (IQR: 1.6-2.6). Clinical time parameters included: median time from initial assessment to admit order, 4.1 hours (IQR: 3.1-5.1), assessment to antibiotic administration 4.7 hours (IQR: 3.9-6.7), and assessment to operating room 9.1 hours (IQR: 5.8-12.7). Median length of stay was 1.2 days (range: 0.2-19.5). Given the diagnostic accuracy and favorable clinical outcomes, without the potential risks of ionizing radiation, MRI may supplant the role of CT scans in pediatric appendicitis imaging. Copyright © 2015 Elsevier Inc. All rights reserved.

A two-year longitudinal pilot MRI study of the brainstem in autism.

PubMed

Jou, Roger J; Frazier, Thomas W; Keshavan, Matcheri S; Minshew, Nancy J; Hardan, Antonio Y

2013-08-15

Research has demonstrated the potential role of the brainstem in the pathobiology of autism. Previous studies have suggested reductions in brainstem volume and a relationship between this structure and sensory abnormalities. However, little is known regarding the developmental aspects of the brainstem across childhood and adolescence. The goal of this pilot study was to examine brainstem development via MRI volumetry using a longitudinal research design. Participants included 23 boys with autism and 23 matched controls (age range=8-17 years), all without intellectual disability. Participants underwent structural MRI scans once at baseline and again at two-year follow-up. Brainstem volumetric measurements were performed using the BRAINS2 software package. There were no significant group differences in age, gender, handedness, and total brain volume; however, full-scale IQ was higher in controls. Autism and control groups showed different patterns of growth in brainstem volume. While whole brainstem volume remained stable in controls over the two-year period, the autism group showed increases with age reaching volumes comparable to controls by age 15 years. This increase of whole brainstem volume was primarily driven by bilateral increases in gray matter volume. Findings from this preliminary study are suggestive of developmental brainstem abnormalities in autism primarily involving gray matter structures. These findings are consistent with autism being conceptualized as a neurodevelopmental disorder with alterations in brain-growth trajectories. More longitudinal MRI studies are needed integrating longitudinal cognitive/behavioral data to confirm and elucidate the clinical significance of these atypical growth patterns. Copyright © 2013 Elsevier B.V. All rights reserved.

Selective laser melting of titanium alloy enables osseointegration of porous multi-rooted implants in a rabbit model.

PubMed

Peng, Wei; Xu, Liangwei; You, Jia; Fang, Lihua; Zhang, Qing

2016-07-21

Osseointegration refers to the direct connection between living bone and the surface of a load-bearing artificial implant. Porous implants with well-controlled porosity and pore size can enhance osseointegration. However, until recently implants were produced by machining solid core titanium rods. The aim of this study was to develop a multi-rooted dental implant (MRI) with a connected porous surface structure to facilitate osseointegration. MRIs manufactured by selective laser melting (SLM) and commercial implants with resorbable blasting media (RBM)-treated surfaces were inserted into the hind limbs of New Zealand white rabbits. Osseointegration was evaluated periodically over 12 weeks by micro-computerized tomography (CT) scanning, histological analysis, mechanical push-out tests, and torque tests. Bone volume densities were consistently higher in the MRI group than in the RBM group throughout the study period, ultimately resulting in a peak value of 48.41 % for the MRI group. Histological analysis revealed denser surrounding bone growth in the MRIs; after 4 and 8 weeks, bone tissue had grown into the pore structures and root bifurcation areas, respectively. Biomechanics tests indicated binding of the porous MRIs to the neobone tissues, as push-out forces strengthened from 294.7 to 446.5 N and maximum mean torque forces improved from 81.15 to 289.57 N (MRI), versus 34.79 to 87.8 N in the RBM group. MRIs manufactured by SLM possess a connected porous surface structure that improves the osteogenic characteristics of the implant surface.

Towards motion insensitive EEG-fMRI: Correcting motion-induced voltages and gradient artefact instability in EEG using an fMRI prospective motion correction (PMC) system.

PubMed

Maziero, Danilo; Velasco, Tonicarlo R; Hunt, Nigel; Payne, Edwin; Lemieux, Louis; Salmon, Carlos E G; Carmichael, David W

2016-09-01

The simultaneous acquisition of electroencephalography and functional magnetic resonance imaging (EEG-fMRI) is a multimodal technique extensively applied for mapping the human brain. However, the quality of EEG data obtained within the MRI environment is strongly affected by subject motion due to the induction of voltages in addition to artefacts caused by the scanning gradients and the heartbeat. This has limited its application in populations such as paediatric patients or to study epileptic seizure onset. Recent work has used a Moiré-phase grating and a MR-compatible camera to prospectively update image acquisition and improve fMRI quality (prospective motion correction: PMC). In this study, we use this technology to retrospectively reduce the spurious voltages induced by motion in the EEG data acquired inside the MRI scanner, with and without fMRI acquisitions. This was achieved by modelling induced voltages from the tracking system motion parameters; position and angles, their first derivative (velocities) and the velocity squared. This model was used to remove the voltages related to the detected motion via a linear regression. Since EEG quality during fMRI relies on a temporally stable gradient artefact (GA) template (calculated from averaging EEG epochs matched to scan volume or slice acquisition), this was evaluated in sessions both with and without motion contamination, and with and without PMC. We demonstrate that our approach is capable of significantly reducing motion-related artefact with a magnitude of up to 10mm of translation, 6° of rotation and velocities of 50mm/s, while preserving physiological information. We also demonstrate that the EEG-GA variance is not increased by the gradient direction changes associated with PMC. Provided a scan slice-based GA template is used (rather than a scan volume GA template) we demonstrate that EEG variance during motion can be supressed towards levels found when subjects are still. In summary, we show that PMC can be used to dramatically improve EEG quality during large amplitude movements, while benefiting from previously reported improvements in fMRI quality, and does not affect EEG data quality in the absence of large amplitude movements. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

68Ga-DOTATATE uptake in pineal gland, a rare physiological variant: case series.

PubMed

Riaz, Saima; Syed, Rizwan; Skoura, Evangelia; Alshammari, Alshaima; Gaze, Mark; Sajjan, Rakesh; Halsey, Richard; Bomanji, Jamshed

2015-11-01

(68)Ga-DOTATATE PET-CT is widely used for the evaluation of neuroendocrine tumours. Knowledge of the physiological distribution of the radiotracer is of critical importance in characterizing focal areas of uptake. In this case series, we report three paediatric cases (average age 4.7 years ± 0.6 SD) with diagnosed advanced stage IV Neuroblastoma. Two had (68)Ga-DOTATATE PET-CT scans and one underwent (68)Ga-DOTATATE PET-MRI scan to assess for suitability of molecular therapy. Focal increased tracer uptake in the pineal gland was noted in all cases with no morphological abnormality on the corresponding CT and MRI scans. The uptake within the gland was thought to be a physiological variant rather than metastases owing to the heterogeneity of somatostatin receptors expression. The pineal gland has been reported to express somatostatin receptors. The physiological distribution of (68)Ga-DOTATATE uptake in the pineal gland is not routinely seen. Furthermore, the possibility of pineal meningioma is very unlikely as pineal meningiomas are very rare and there was no convincing morphological evidence of meningiomas on CT/MRI scan.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swanick, Cameron W.; Castle, Katherine O.; Vedam, Sastry

Purpose: We prospectively compared computed tomography (CT)– and magnetic resonance imaging (MRI)–based high-risk clinical target volume (HR-CTV) contours at the time of brachytherapy for cervical cancer in an effort to identify patients who might benefit most from MRI-based planning. Methods and Materials: Thirty-seven patients who had undergone a pretreatment diagnostic MRI scan were included in the analysis. We delineated the HR-CTV on the brachytherapy CT and brachytherapy MRI scans independently for each patient. We then calculated the absolute volumes for each HR-CTV and the Dice coefficient of similarity (DC, a measure of spatial agreement) for the HR-CTV contours. We identifiedmore » the clinical and tumor factors associated with (1) a discrepancy in volume between the CT HR-CTV and MRI HR-CTV contours; and (2) DC. The mean values were compared using 1-way analysis of variance or paired or unpaired t tests, as appropriate. Simple and multivariable linear regression analyses were used to model the effects of covariates on the outcomes. Results: Patients with International Federation of Gynecology and Obstetrics stage IB to IVA cervical cancer were treated with intracavitary brachytherapy using tandem and ovoid (n=33) or tandem and cylinder (n=4) applicators. The mean CT HR-CTV volume (44.1 cm{sup 3}) was larger than the mean MRI HR-CTV volume (35.1 cm{sup 3}; P<.0001, paired t test). On multivariable analysis, a higher body mass index (BMI) and tumor size ≥5 cm with parametrial invasion on the MRI scan at diagnosis were associated with an increased discrepancy in volume between the HR-CTV contours (P<.02 for both). In addition, the spatial agreement (as measured by DC) between the HR-CTV contours decreased with an increasing BMI (P=.013). Conclusions: We recommend MRI-based brachytherapy planning for patients with tumors >5 cm and parametrial invasion on MRI at diagnosis and for those with a high BMI.« less

Clinical values of (18) F-FDG PET/CT in oral cavity cancer with dental artifacts on CT or MRI.

PubMed

Hong, Hye Ran; Jin, Soyoung; Koo, Hyun Jung; Roh, Jong-Lyel; Kim, Jae Seung; Cho, Kyung-Ja; Choi, Seung-Ho; Nam, Soon Yuhl; Kim, Sang Yoon

2014-11-01

2a To investigate the role of (18) F-FDG PET/CT in tumor staging, extent, and volume measurements in oral cavity squamous cell carcinoma (OSCC) patients with/without dental artifacts on CT or MRI. This study was conducted in 63 consecutive patients with OSCC who received initial workups including (18) F-FDG PET/CT and MRI. The results of the imaging modalities were compared to those of pathology, using McNemar's test and the paired t-test. Thirty-seven patients (59%) had dental or metallic artifacts obscuring primary tumors. (18) F-FDG PET/CT scanning was superior to MRI in tumor staging (weighted κ = 0.870 vs. 0.518, P = 0.004) in patients with dental artifacts. In addition, (18) F-FDG PET/CT scans were more specific than MRI in detecting sublingual gland (P = 0.014) and mouth floor (P = 0.011) involvement. In patients with dental artifacts, there was a significant discrepancy between primary tumor volume (PTV) measured by pathology and MRI (P = 0.018), but not between PTV measured from pathology and (18) F-FDG PET/CT at SUV2.5 (P = 0.245), which showed the highest intraclass correlation coefficient value (0.860). (18) F-FDG PET/CT scans provide accurate tumor staging and volume measurements in OSCC patients with CR/MRI dental artifacts, leading to improved preoperative planning. 2b CONDENSED ABSTRACT This study evaluated the clinical value of (18) F-FDG PET/CT in 63 patients with oral cavity cancers. In 37 (59%) patients with dental artifacts on CT/MRI, (18) F-FDG PET/CT showed superior results compared to MRI in tumor staging and represented the highest intraclass correlation coefficient value to tumor volume determined by pathology. © 2014 Wiley Periodicals, Inc.

Quantifying the ultrastructure of carotid arteries using high-resolution micro-diffusion tensor imaging—comparison of intact versus open cut tissue

NASA Astrophysics Data System (ADS)

Salman Shahid, Syed; Gaul, Robert T.; Kerskens, Christian; Flamini, Vittoria; Lally, Caitríona

2017-12-01

Diffusion magnetic resonance imaging (dMRI) can provide insights into the microstructure of intact arterial tissue. The current study employed high magnetic field MRI to obtain ultra-high resolution dMRI at an isotropic voxel resolution of 117 µm3 in less than 2 h of scan time. A parameter selective single shell (128 directions) diffusion-encoding scheme based on Stejskel-Tanner sequence with echo-planar imaging (EPI) readout was used. EPI segmentation was used to reduce the echo time (TE) and to minimise the susceptibility-induced artefacts. The study utilised the dMRI analysis with diffusion tensor imaging (DTI) framework to investigate structural heterogeneity in intact arterial tissue and to quantify variations in tissue composition when the tissue is cut open and flattened. For intact arterial samples, the region of interest base comparison showed significant differences in fractional anisotropy and mean diffusivity across the media layer (p  <  0.05). For open cut flat samples, DTI based directionally invariant indices did not show significant differences across the media layer. For intact samples, fibre tractography based indices such as calculated helical angle and fibre dispersion showed near circumferential alignment and a high degree of fibre dispersion, respectively. This study demonstrates the feasibility of fast dMRI acquisition with ultra-high spatial and angular resolution at 7 T. Using the optimised sequence parameters, this study shows that DTI based markers are sensitive to local structural changes in intact arterial tissue samples and these markers may have clinical relevance in the diagnosis of atherosclerosis and aneurysm.

Magnet dislocation: an increasing and serious complication following MRI in patients with cochlear implants.

PubMed

Hassepass, F; Stabenau, V; Arndt, S; Beck, R; Bulla, S; Grauvogel, T; Aschendorff, A

2014-07-01

Cochlear implantation (CI) represents the gold standard in the treatment of children born deaf and postlingually deafened adults. Initial magnetic resonance imaging (MRI) was contraindicated in CI users. Meanwhile, there are specific recommendations concerning MRI compatibility depending on the type of CI system and the device manufacturer. Some CI systems are even approved for MRI with the internal magnet left in place. The aim of this study was to analyze all magnet revision surgeries in CI patients at one CI center and the relationship to MRI scans over time. Between 2000 and 2013, a total of 2027 CIs were implanted. The number of magnet dislocation (MD) surgeries and their causes was assessed retrospectively. In total 12 cases of MD resulting from an MRI scan (0.59 %) were observed, accounting for 52.2 % of all magnetic revision surgeries. As per the labeling, it was considered safe to leave the internal magnet in place during MRI while following specific manufacturer recommendations: MRI intensity of 1.5 Tesla (T) and compression head bandage during examination. A compression head bandage in a 1.5 T MRI unit does not safely prevent MD and the related serious complications in CI recipients. We recommend a Stenvers view radiograph after MRI with the internal magnet in place for early identification of MD, at least in the case of pain during or after MRI examination. MRI in CI patients should be indicated with restraint and patients should be explicitly informed about the possible risks. Recommendations regarding MRI compatibility and the handling of CI patients issued with MRI for the most common CI systems are summarized. © Georg Thieme Verlag KG Stuttgart · New York.

Compact Intraoperative MRI: Stereotactic Accuracy and Future Directions.

PubMed

Markowitz, Daniel; Lin, Dishen; Salas, Sussan; Kohn, Nina; Schulder, Michael

2017-01-01

Intraoperative imaging must supply data that can be used for accurate stereotactic navigation. This information should be at least as accurate as that acquired from diagnostic imagers. The aim of this study was to compare the stereotactic accuracy of an updated compact intraoperative MRI (iMRI) device based on a 0.15-T magnet to standard surgical navigation on a 1.5-T diagnostic scan MRI and to navigation with an earlier model of the same system. The accuracy of each system was assessed using a water-filled phantom model of the brain. Data collected with the new system were compared to those obtained in a previous study assessing the older system. The accuracy of the new iMRI was measured against standard surgical navigation on a 1.5-T MRI using T1-weighted (W) images. The mean error with the iMRI using T1W images was lower than that based on images from the 1.5-T scan (1.24 vs. 2.43 mm). T2W images from the newer iMRI yielded a lower navigation error than those acquired with the prior model (1.28 vs. 3.15 mm). Improvements in magnet design can yield progressive increases in accuracy, validating the concept of compact, low-field iMRI. Avoiding the need for registration between image and surgical space increases navigation accuracy. © 2017 S. Karger AG, Basel.

Measurement of brain perfusion in newborns: Pulsed arterial spin labeling (PASL) versus pseudo-continuous arterial spin labeling (pCASL)

PubMed Central

Boudes, Elodie; Gilbert, Guillaume; Leppert, Ilana Ruth; Tan, Xianming; Pike, G. Bruce; Saint-Martin, Christine; Wintermark, Pia

2014-01-01

Background Arterial spin labeling (ASL) perfusion-weighted imaging (PWI) by magnetic resonance imaging (MRI) has been shown to be useful for identifying asphyxiated newborns at risk of developing brain injury, whether or not therapeutic hypothermia was administered. However, this technique has been only rarely used in newborns until now, because of the challenges to obtain sufficient signal-to-noise ratio (SNR) and spatial resolution in newborns. Objective To compare two methods of ASL-PWI (i.e., single inversion-time pulsed arterial spin labeling [single TI PASL], and pseudo-continuous arterial spin labeling [pCASL]) to assess brain perfusion in asphyxiated newborns treated with therapeutic hypothermia and in healthy newborns. Design/methods We conducted a prospective cohort study of term asphyxiated newborns meeting the criteria for therapeutic hypothermia; four additional healthy term newborns were also included as controls. Each of the enrolled newborns was scanned at least once during the first month of life. Each MRI scan included conventional anatomical imaging, as well as PASL and pCASL PWI-MRI. Control and labeled images were registered separately to reduce the effect of motion artifacts. For each scan, the axial slice at the level of the basal ganglia was used for comparisons. Each scan was scored for its image quality. Quantification of whole-slice cerebral blood flow (CBF) was done afterwards using previously described formulas. Results A total number of 61 concomitant PASL and pCASL scans were obtained in nineteen asphyxiated newborns treated with therapeutic hypothermia and four healthy newborns. After discarding the scans with very poor image quality, 75% (46/61) remained for comparison between the two ASL methods. pCASL images presented a significantly superior image quality score compared to PASL images (p < 0.0001). Strong correlation was found between the CBF measured by PASL and pCASL (r = 0.61, p < 0.0001). Conclusion This study demonstrates that both ASL methods are feasible to assess brain perfusion in healthy and sick newborns. However, pCASL might be a better choice over PASL in newborns, as pCASL perfusion maps had a superior image quality that allowed a more detailed identification of the different brain structures. PMID:25379424

Follow-up of cortical activity and structure after lesion with laser speckle imaging and magnetic resonance imaging in nonhuman primates

NASA Astrophysics Data System (ADS)

Peuser, Jörn; Belhaj-Saif, Abderraouf; Hamadjida, Adjia; Schmidlin, Eric; Gindrat, Anne-Dominique; Völker, Andreas Charles; Zakharov, Pavel; Hoogewoud, Henri-Marcel; Rouiller, Eric M.; Scheffold, Frank

2011-09-01

The nonhuman primate model is suitable to study mechanisms of functional recovery following lesion of the cerebral cortex (motor cortex), on which therapeutic strategies can be tested. To interpret behavioral data (time course and extent of functional recovery), it is crucial to monitor the properties of the experimental cortical lesion, induced by infusion of the excitotoxin ibotenic acid. In two adult macaque monkeys, ibotenic acid infusions produced a restricted, permanent lesion of the motor cortex. In one monkey, the lesion was monitored over 3.5 weeks, combining laser speckle imaging (LSI) as metabolic readout (cerebral blood flow) and anatomical assessment with magnetic resonance imaging (T2-weighted MRI). The cerebral blood flow, measured online during subsequent injections of the ibotenic acid in the motor cortex, exhibited a dramatic increase, still present after one week, in parallel to a MRI hypersignal. After 3.5 weeks, the cerebral blood flow was strongly reduced (below reference level) and the hypersignal disappeared from the MRI scan, although the lesion was permanent as histologically assessed post-mortem. The MRI data were similar in the second monkey. Our experiments suggest that LSI and MRI, although they reflect different features, vary in parallel during a few weeks following an excitotoxic cortical lesion.

Free-breathing 3D Cardiac MRI Using Iterative Image-Based Respiratory Motion Correction

PubMed Central

Moghari, Mehdi H.; Roujol, Sébastien; Chan, Raymond H.; Hong, Susie N.; Bello, Natalie; Henningsson, Markus; Ngo, Long H.; Goddu, Beth; Goepfert, Lois; Kissinger, Kraig V.; Manning, Warren J.; Nezafat, Reza

2012-01-01

Respiratory motion compensation using diaphragmatic navigator (NAV) gating with a 5 mm gating window is conventionally used for free-breathing cardiac MRI. Due to the narrow gating window, scan efficiency is low resulting in long scan times, especially for patients with irregular breathing patterns. In this work, a new retrospective motion compensation algorithm is presented to reduce the scan time for free-breathing cardiac MRI that increasing the gating window to 15 mm without compromising image quality. The proposed algorithm iteratively corrects for respiratory-induced cardiac motion by optimizing the sharpness of the heart. To evaluate this technique, two coronary MRI datasets with 1.3 mm3 resolution were acquired from 11 healthy subjects (7 females, 25±9 years); one using a NAV with a 5 mm gating window acquired in 12.0±2.0 minutes and one with a 15 mm gating window acquired in 7.1±1.0 minutes. The images acquired with a 15 mm gating window were corrected using the proposed algorithm and compared to the uncorrected images acquired with the 5 mm and 15 mm gating windows. The image quality score, sharpness, and length of the three major coronary arteries were equivalent between the corrected images and the images acquired with a 5 mm gating window (p-value>0.05), while the scan time was reduced by a factor of 1.7. PMID:23132549

Influence of amplitude-related perfusion parameters in the parotid glands by non-fat-saturated dynamic contrast-enhanced magnetic resonance imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiu, Su-Chin; Cheng, Cheng-Chieh; Chang, Hing-Chiu

Purpose: To verify whether quantification of parotid perfusion is affected by fat signals on non-fat-saturated (NFS) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and whether the influence of fat is reduced with fat saturation (FS). Methods: This study consisted of three parts. First, a retrospective study analyzed DCE-MRI data previously acquired on different patients using NFS (n = 18) or FS (n = 18) scans. Second, a phantom study simulated the signal enhancements in the presence of gadolinium contrast agent at six concentrations and three fat contents. Finally, a prospective study recruited nine healthy volunteers to investigate the influence of fatmore » suppression on perfusion quantification on the same subjects. Parotid perfusion parameters were derived from NFS and FS DCE-MRI data using both pharmacokinetic model analysis and semiquantitative parametric analysis. T tests and linear regression analysis were used for statistical analysis with correction for multiple comparisons. Results: NFS scans showed lower amplitude-related parameters, including parameter A, peak enhancement (PE), and slope than FS scans in the patients (all with P < 0.0167). The relative signal enhancement in the phantoms was proportional to the dose of contrast agent and was lower in NFS scans than in FS scans. The volunteer study showed lower parameter A (6.75 ± 2.38 a.u.), PE (42.12% ± 14.87%), and slope (1.43% ± 0.54% s{sup −1}) in NFS scans as compared to 17.63 ± 8.56 a.u., 104.22% ± 25.15%, and 9.68% ± 1.67% s{sup −1}, respectively, in FS scans (all with P < 0.005). These amplitude-related parameters were negatively associated with the fat content in NFS scans only (all with P < 0.05). Conclusions: On NFS DCE-MRI, quantification of parotid perfusion is adversely affected by the presence of fat signals for all amplitude-related parameters. The influence could be reduced on FS scans.« less

Selective magnetic resonance imaging (MRI) in invasive lobular breast cancer based on mammographic density: does it lead to an appropriate change in surgical treatment?

PubMed

Bansal, Gaurav J; Santosh, Divya; Davies, Eleri L

2016-01-01

The purpose of this study was to evaluate whether high mammographic density can be used as one of the selection criteria for MRI in invasive lobular breast cancer (ILC). In our institute, high breast density has been used as one of the indications for performing MRI scan in patients with ILC. We divided the patients in two groups, one with MRI performed pre-operatively and other without MRI. We compared their surgical procedures and analyzed whether surgical plan was altered after MRI. In case of alteration of plan, we analyzed whether the change was adequate by comparing post-operative histological findings. Between 2011 and 2015, there were a total of 1601 breast cancers with 97 lobular cancers, out of which 36 had pre-operative MRI and 61 had no MRI scan. 12 (33.3%) had mastectomy following MRI, out of which 9 (25%) had change in surgical plan from conservation to mastectomy following MRI. There were no unnecessary mastectomies in the MRI group. However, utilization of MRI in this cohort of patients did not reduce reoperation rate (19.3%). Lobular carcinoma in situ (LCIS) was identified in 60% of reoperations on post-surgical histology. Patients in the "No MRI" group had higher mastectomy rate 26 (42.6%), which was again appropriate. High mammographic density is a useful risk stratification criterion for selective MRI in ILC within a multidisciplinary team meeting setting. Provided additional lesions identified on MRI are confirmed with biopsy, pre-operative MRI does not cause unnecessary mastectomies. Used in this selective manner, reoperation rates were not eliminated, albeit reduced when compared to literature. High mammographic breast density can be used as one of the selection criteria for pre-operative MRI in ILC without an increase in inappropriate mastectomies with potential time and cost savings. In this cohort, re-excisions were not reduced markedly with pre-operative MRI.

Clinical safety of the ProMRI pacemaker system in patients subjected to thoracic spine and cardiac 1.5-T magnetic resonance imaging scanning conditions.

PubMed

Bailey, William M; Mazur, Alexander; McCotter, Craig; Woodard, Pamela K; Rosenthal, Lawrence; Johnson, Whitney; Mela, Theofanie

2016-02-01

Permanent cardiac pacemakers have historically been considered a contraindication to magnetic resonance imaging (MRI). The purpose of the ProMRI Phase B Study, a multicenter, prospective, single-arm, nonrandomized study, was to evaluate the clinical safety of the Biotronik ProMRI pacemaker system in patients undergoing thoracic spine and cardiac MRI. The ProMRI Phase B study enrolled 245 patients with stable baseline pacing indices implanted with an Entovis pacemaker (DR-T or SR-T) and Setrox 53-cm and/or 60-cm lead(s). Device interrogation was performed at enrollment, pre- and post-MRI scan, and 1 and 3 months post-MRI. End-points were (1) freedom from MRI- and pacing system-related serious adverse device effects through 1 month post-MRI; (2) freedom from atrial and ventricular MRI-induced pacing threshold increase (>0.5 V); and (3) freedom from P- and R-wave amplitude attenuation (<50%), or P wave <1.5 mV, or R wave <5.0 mV at 1 month post-MRI. In total, 216 patients completed the MRI and 1-month post-MRI follow-up. One adverse event possibly related to the implanted system and the MRI procedure occurred, resulting in a serious adverse device effect-free rate of 99.6% (220/221; P < .0001. Freedom from atrial and ventricular pacing threshold increase was 100% (194/194, P < .001) and 100% (206/206, P < .001) respectively. Freedom from P- and R-wave amplitude attenuation was 98.2% (167/170, P < .001) and 100% (188/188, P < .001) respectively. The results of the ProMRI Phase B study demonstrate the clinical safety and efficacy of the ProMRI pacemaker system in patients subjected to thoracic spine and cardiac MRI conditions. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

MRI: Is Gadolinium Safe for People with Kidney Problems?

MedlinePlus

... M.D. It depends on the type of magnetic resonance imaging (MRI) scan you're scheduled to ... org," "Mayo Clinic Healthy Living," and the triple-shield Mayo Clinic logo are trademarks of Mayo Foundation ...

Gradient Echo MRI Characterization of Development of Atherosclerosis in the Abdominal Aorta in Watanabe Heritable Hyperlipidemic Rabbits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yi-Xiang J., E-mail: yi-xiang.wang@astrazeneca.com; Kuribayashi, Hideto; Wagberg, Maria

Purpose. The Watanabe Heritable Hyperlipidemic (WHHL) rabbit provides an important model of spontaneous atherosclerosis. With a strain of WHHL rabbits which do not develop abdominal aorta lumen stenosis even with advanced atherosclerosis, we studied the MRI-histology correlation, and the natural progression of atherosclerosis in the abdominal aorta. In addition, intra-reader segmentation repeatability and scan-rescan reproducibility were assessed. Methods. Two batches of female WHHL rabbits were used. The first batch of 6 rabbits was scanned at 20 weeks old. A second batch of 17 rabbits was scanned at 50 weeks old and then randomly divided into two subgroups: 8 were killedmore » for histologic investigation; 9 were kept alive for follow-up, with repeat scanning a week later to assess scan-rescan reproducibility, and again at 73 weeks old to assess disease progression. MR images were acquired at 4.7 T using a chemical shift selective fat suppression gradient echo with a saturation band suppressing blood signal within the aortic lumen. Five slices per animal were acquired, centered around the renal artery region of the abdominal aorta, with in-plane resolution of 0.195 mm and slice thickness of 3 mm. Results. The coefficient of variation for intra-reader reproducibility for aortic wall thickness measurements was 2.5% for repeat segmentations of the same scans on the same day, but segmentations of these same scans made 8 months later showed a systematic change, suggesting that intra-reader bias as well as increased variability could compromise assessments made over time. Comparative analyses were therefore performed in one postprocessing session. The coefficient of variation for scan-rescan reproducibility for aortic wall thickness was 5.5% for nine pairs of scans acquired a week apart and segmented on the same day. Good MRI-histology correlation was obtained. The MRI-measured mean aortic wall thickness of animals at 20 weeks of age was 76% that of animals at 50 weeks of age (p < 0.001). There was a small increase in aortic wall thickness between 50 and 73 weeks of age, but this was not significant (p > 0.05). The corresponding differences in lumen cross-sectional areas at 20, 50, and 73 weeks of age were not significant. These results were consistent with in-house historical histology data on this strain of rabbits. Conclusions. High-resolution gradient echo MRI can follow disease progression in the WHHL rabbit spontaneous atherosclerosis disease model.« less

Correlative studies of structural and functional imaging in primary progressive aphasia.

PubMed

Panegyres, P K; McCarthy, M; Campbell, A; Lenzo, N; Fallon, M; Thompson, J

2008-01-01

To compare and contrast structural and functional imaging in primary progressive aphasia (PPA). A cohort of 8 patients diagnosed with PPA presenting with nonfluency were prospectively evaluated. All patients had structural imaging in the form of MRI and in 1 patient CAT scanning on account of a cardiac pacemaker. All patients had single-photon emission computed tomography (SPECT) and positron emission tomography (PET) imaging. SPECT and PET imaging had 100% correlation. Anatomical imaging was abnormal in only 6 of the 8 patients. Wernicke's area showed greater peak Z score reduction and extent of area affected than Broca's area (McNemar paired test: P = .008 for Z score reduction; P = .0003 for extent). PET scanning revealed significant involvement of the anterior cingulum. Functional imaging in PPA: (a) identified more patients correctly than anatomic imaging highlighting the importance of SPECT and PET in the diagnosis; and (b) demonstrated the heterogeneous involvement of disordered linguistic networks in PPA suggesting its syndromic nature.

Using radioactive drugs could lead to better imaging of prostate cancer | Center for Cancer Research

Cancer.gov

Medical imaging (x-ray, ultrasound, MRI, CT, PET scan) is a noninvasive way to view the internal structures of the body. However, these tools are not ideal for detecting cancer that has spread, or metastasized, because the precise location of these cancer cells is unknown. Researchers are now testing an experimental radiotracer called 18F-DCFPyL to help find sites of cancer in the body.  Learn more...

The pros and cons of intraoperative CT scan in evaluation of deep brain stimulation lead implantation: A retrospective study

PubMed Central

Servello, Domenico; Zekaj, Edvin; Saleh, Christian; Pacchetti, Claudio; Porta, Mauro

2016-01-01

Background: Deep brain stimulation (DBS) is an established therapy for movement disorders, such as Parkinson's disease (PD), dystonia, and tremor. The efficacy of DBS depends on the correct lead positioning. The commonly adopted postoperative radiological evaluation is performed with computed tomography (CT) scan and/or magnetic resonance imaging (MRI). Methods: We conducted a retrospective study on 202 patients who underwent DBS from January 2009 to October 2013. DBS indications were PD, progressive supranuclear palsy, tremor, dystonia, Tourette syndrome, obsessive compulsive disorder, depression, and Huntington's disease. Preoperatively, all patients underwent brain MRI and brain CT scan with the stereotactic frame positioned. The lead location was confirmed intraoperatively with CT. The CT images were subsequently transferred to the Stealth Station Medtronic and merged with the preoperative planning. On the first or second day after, implantation we performed a brain MRI to confirm the correct position of the lead. Results: In 14 patients, leads were in suboptimal position after intraoperative CT scan positioning. The cases with alteration in the Z-axis were corrected immediately under fluoroscopic guidance. In all the 14 patients, an immediate repositioning was done. Conclusions: Based on our data, intraoperative CT scan is fast, safe, and a useful tool in the evaluation of the position of the implanted lead. It also reduces the patient's discomfort derived from the transfer of the patient from the operating room to the radiological department. However, intraoperative CT should not be considered as a substitute for postoperative MRI. PMID:27583182

Development of a patient-specific anatomical foot model from structured light scan data.

PubMed

Lochner, Samuel J; Huissoon, Jan P; Bedi, Sanjeev S

2014-01-01

The use of anatomically accurate finite element (FE) models of the human foot in research studies has increased rapidly in recent years. Uses for FE foot models include advancing knowledge of orthotic design, shoe design, ankle-foot orthoses, pathomechanics, locomotion, plantar pressure, tissue mechanics, plantar fasciitis, joint stress and surgical interventions. Similar applications but for clinical use on a per-patient basis would also be on the rise if it were not for the high costs associated with developing patient-specific anatomical foot models. High costs arise primarily from the expense and challenges of acquiring anatomical data via magnetic resonance imaging (MRI) or computed tomography (CT) and reconstructing the three-dimensional models. The proposed solution morphs detailed anatomy from skin surface geometry and anatomical landmarks of a generic foot model (developed from CT or MRI) to surface geometry and anatomical landmarks acquired from an inexpensive structured light scan of a foot. The method yields a patient-specific anatomical foot model at a fraction of the cost of standard methods. Average error for bone surfaces was 2.53 mm for the six experiments completed. Highest accuracy occurred in the mid-foot and lowest in the forefoot due to the small, irregular bones of the toes. The method must be validated in the intended application to determine if the resulting errors are acceptable.

Safety and EEG data quality of concurrent high-density EEG and high-speed fMRI at 3 Tesla.

PubMed

Foged, Mette Thrane; Lindberg, Ulrich; Vakamudi, Kishore; Larsson, Henrik B W; Pinborg, Lars H; Kjær, Troels W; Fabricius, Martin; Svarer, Claus; Ozenne, Brice; Thomsen, Carsten; Beniczky, Sándor; Paulson, Olaf B; Posse, Stefan

2017-01-01

Concurrent EEG and fMRI is increasingly used to characterize the spatial-temporal dynamics of brain activity. However, most studies to date have been limited to conventional echo-planar imaging (EPI). There is considerable interest in integrating recently developed high-speed fMRI methods with high-density EEG to increase temporal resolution and sensitivity for task-based and resting state fMRI, and for detecting interictal spikes in epilepsy. In the present study using concurrent high-density EEG and recently developed high-speed fMRI methods, we investigate safety of radiofrequency (RF) related heating, the effect of EEG on cortical signal-to-noise ratio (SNR) in fMRI, and assess EEG data quality. The study compared EPI, multi-echo EPI, multi-band EPI and multi-slab echo-volumar imaging pulse sequences, using clinical 3 Tesla MR scanners from two different vendors that were equipped with 64- and 256-channel MR-compatible EEG systems, respectively, and receive only array head coils. Data were collected in 11 healthy controls (3 males, age range 18-70 years) and 13 patients with epilepsy (8 males, age range 21-67 years). Three of the healthy controls were scanned with the 256-channel EEG system, the other subjects were scanned with the 64-channel EEG system. Scalp surface temperature, SNR in occipital cortex and head movement were measured with and without the EEG cap. The degree of artifacts and the ability to identify background activity was assessed by visual analysis by a trained expert in the 64 channel EEG data (7 healthy controls, 13 patients). RF induced heating at the surface of the EEG electrodes during a 30-minute scan period with stable temperature prior to scanning did not exceed 1.0° C with either EEG system and any of the pulse sequences used in this study. There was no significant decrease in cortical SNR due to the presence of the EEG cap (p > 0.05). No significant differences in the visually analyzed EEG data quality were found between EEG recorded during high-speed fMRI and during conventional EPI (p = 0.78). Residual ballistocardiographic artifacts resulted in 58% of EEG data being rated as poor quality. This study demonstrates that high-density EEG can be safely implemented in conjunction with high-speed fMRI and that high-speed fMRI does not adversely affect EEG data quality. However, the deterioration of the EEG quality due to residual ballistocardiographic artifacts remains a significant constraint for routine clinical applications of concurrent EEG-fMRI.

Inferring pathobiology from structural MRI in schizophrenia and bipolar disorder: Modeling head motion and neuroanatomical specificity.

PubMed

Yao, Nailin; Winkler, Anderson M; Barrett, Jennifer; Book, Gregory A; Beetham, Tamara; Horseman, Rachel; Leach, Olivia; Hodgson, Karen; Knowles, Emma E; Mathias, Samuel; Stevens, Michael C; Assaf, Michal; van Erp, Theo G M; Pearlson, Godfrey D; Glahn, David C

2017-08-01

Despite over 400 peer-reviewed structural MRI publications documenting neuroanatomic abnormalities in bipolar disorder and schizophrenia, the confounding effects of head motion and the regional specificity of these defects are unclear. Using a large cohort of individuals scanned on the same research dedicated MRI with broadly similar protocols, we observe reduced cortical thickness indices in both illnesses, though less pronounced in bipolar disorder. While schizophrenia (n = 226) was associated with wide-spread surface area reductions, bipolar disorder (n = 227) and healthy comparison subjects (n = 370) did not differ. We replicate earlier reports that head motion (estimated from time-series data) influences surface area and cortical thickness measurements and demonstrate that motion influences a portion, but not all, of the observed between-group structural differences. Although the effect sizes for these differences were small to medium, when global indices were covaried during vertex-level analyses, between-group effects became nonsignificant. This analysis raises doubts about the regional specificity of structural brain changes, possible in contrast to functional changes, in affective and psychotic illnesses as measured with current imaging technology. Given that both schizophrenia and bipolar disorder showed cortical thickness reductions, but only schizophrenia showed surface area changes, and assuming these measures are influenced by at least partially unique sets of biological factors, then our results could indicate some degree of specificity between bipolar disorder and schizophrenia. Hum Brain Mapp 38:3757-3770, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Evidence for Model-based Computations in the Human Amygdala during Pavlovian Conditioning

PubMed Central

Prévost, Charlotte; McNamee, Daniel; Jessup, Ryan K.; Bossaerts, Peter; O'Doherty, John P.

2013-01-01

Contemporary computational accounts of instrumental conditioning have emphasized a role for a model-based system in which values are computed with reference to a rich model of the structure of the world, and a model-free system in which values are updated without encoding such structure. Much less studied is the possibility of a similar distinction operating at the level of Pavlovian conditioning. In the present study, we scanned human participants while they participated in a Pavlovian conditioning task with a simple structure while measuring activity in the human amygdala using a high-resolution fMRI protocol. After fitting a model-based algorithm and a variety of model-free algorithms to the fMRI data, we found evidence for the superiority of a model-based algorithm in accounting for activity in the amygdala compared to the model-free counterparts. These findings support an important role for model-based algorithms in describing the processes underpinning Pavlovian conditioning, as well as providing evidence of a role for the human amygdala in model-based inference. PMID:23436990

The Involvement of Speed-of-Processing in Story Listening in Preschool Children: A Functional and Structural Connectivity Study.

PubMed

Horowitz-Kraus, Tzipi; Farah, Rola; DiFrancesco, Mark; Vannest, Jennifer

2017-02-01

Story listening in children relies on brain regions supporting speech perception, auditory word recognition, syntax, semantics, and discourse abilities, along with the ability to attend and process information (part of executive functions). Speed-of-processing is an early-developed executive function. We used functional and structural magnetic resonance imaging (MRI) to demonstrate the relationship between story listening and speed-of-processing in preschool-age children. Eighteen participants performed story-listening tasks during MRI scans. Functional and structural connectivity analysis was performed using the speed-of-processing scores as regressors. Activation in the superior frontal gyrus during story listening positively correlated with speed-of-processing scores. This region was functionally connected with the superior temporal gyrus, insula, and hippocampus. Fractional anisotropy in the inferior frontooccipital fasciculus, which connects the superior frontal and temporal gyri, was positively correlated with speed-of-processing scores. Our results suggest that speed-of-processing skills in preschool-age children are reflected in functional activation and connectivity during story listening and may act as a biomarker for future academic abilities. Georg Thieme Verlag KG Stuttgart · New York.

Detailed T1-Weighted Profiles from the Human Cortex Measured in Vivo at 3 Tesla MRI.

PubMed

Ferguson, Bart; Petridou, Natalia; Fracasso, Alessio; van den Heuvel, Martijn P; Brouwer, Rachel M; Hulshoff Pol, Hilleke E; Kahn, René S; Mandl, René C W

2018-04-01

Studies into cortical thickness in psychiatric diseases based on T1-weighted MRI frequently report on aberrations in the cerebral cortex. Due to limitations in image resolution for studies conducted at conventional MRI field strengths (e.g. 3 Tesla (T)) this information cannot be used to establish which of the cortical layers may be implicated. Here we propose a new analysis method that computes one high-resolution average cortical profile per brain region extracting myeloarchitectural information from T1-weighted MRI scans that are routinely acquired at a conventional field strength. To assess this new method, we acquired standard T1-weighted scans at 3 T and compared them with state-of-the-art ultra-high resolution T1-weighted scans optimised for intracortical myelin contrast acquired at 7 T. Average cortical profiles were computed for seven different brain regions. Besides a qualitative comparison between the 3 T scans, 7 T scans, and results from literature, we tested if the results from dynamic time warping-based clustering are similar for the cortical profiles computed from 7 T and 3 T data. In addition, we quantitatively compared cortical profiles computed for V1, V2 and V7 for both 7 T and 3 T data using a priori information on their relative myelin concentration. Although qualitative comparisons show that at an individual level average profiles computed for 7 T have more pronounced features than 3 T profiles the results from the quantitative analyses suggest that average cortical profiles computed from T1-weighted scans acquired at 3 T indeed contain myeloarchitectural information similar to profiles computed from the scans acquired at 7 T. The proposed method therefore provides a step forward to study cortical myeloarchitecture in vivo at conventional magnetic field strength both in health and disease.

Poor Brain Growth in Extremely Preterm Neonates Long Before the Onset of Autism Spectrum Disorder Symptoms.

PubMed

Padilla, Nelly; Eklöf, Eva; Mårtensson, Gustaf E; Bölte, Sven; Lagercrantz, Hugo; Ådén, Ulrika

2017-02-01

Preterm infants face an increased risk of autism spectrum disorder (ASD). The relationship between autism during childhood and early brain development remains unexplored. We studied 84 preterm children born at <27 weeks of gestation, who underwent neonatal magnetic resonance imaging (MRI) at term and were screened for ASD at 6.5 years. Full-scale intelligence quotient was measured and neonatal morbidities were recorded. Structural brain morphometric studies were performed in 33 infants with high-quality MRI and no evidence of focal brain lesions. Twenty-three (27.4%) of the children tested ASD positive and 61 (72.6%) tested ASD negative. The ASD-positive group had a significantly higher frequency of neonatal complications than the ASD-negative group. In the subgroup of 33 children, the ASD infants had reduced volumes in the temporal, occipital, insular, and limbic regions and in the brain areas involved in social/behavior and salience integration. This study shows that the neonatal MRI scans of extremely preterm children, subsequently diagnosed with ASD at 6.5 years, showed brain structural alterations, localized in the regions that play a key role in the core features of autism. Early detection of these structural alterations may allow the early identification and intervention of children at risk of ASD. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

[Indications for magnetic resonance imaging for low back pain in adults].

PubMed

Millán Ortuondo, E; Cabrera Zubizarreta, A; Muñiz Saitua, J; Sola Sarabia, C; Zubia Arratibel, J

2014-01-01

Low back pain is a common disorder that generates many medical consultations. Magnetic Resonance Imaging (MRI) is commonly used in the clinical management of some of these patients. However, the cost of inappropriate MRI use is high, so there is a need to develop guidelines to help physicians make correct decisions and optimize available resources. To determine the main clinical indications for MRI scanning in adults with low back pain. The RAND/UCLA appropriateness method was used: After a systematic review (May 2012), a list of the clinical indications for MRI scanning in patients with low back pain was prepared. A multidisciplinary expert panel scored each indication from 1, «totally inappropriate» to 9, «totally appropriate». A first on-line round, an in-person panel meeting, where results of the first round were discussed, and a final second on-line round were arranged. A clinical indication was considered appropriate if the median score was 6.5 or higher, and there was agreement between experts (IPRAS index was used). An MRI test is considered appropriate if cancer, spinal infection or a fracture, even with a negative X-ray test is suspected.; if there is inflammatory back pain; severe/progressive neurological deficit; severe and progressive low back pain; subacute or chronic low back pain with radicular involvement unresponsive to conservative therapy. Clinical indications for a MRI scanning are based on the suspicion of a secondary serious pathology. This methodology helps to set clinical indications for MRI, and may be of great value for both clinicians and health managers. Copyright © 2013 SECA. Published by Elsevier Espana. All rights reserved.

Neuroimaging basis in the conversion of aMCI patients with APOE-ε4 to AD: study protocol of a prospective diagnostic trial.

PubMed

Chen, Guan-Qun; Sheng, Can; Li, Yu-Xia; Yu, Yang; Wang, Xiao-Ni; Sun, Yu; Li, Hong-Yan; Li, Xuan-Yu; Xie, Yun-Yan; Han, Ying

2016-05-12

The ε4 allele of the Apolipoprotein E gene (APOE-ε4) is a potent genetic risk factor for sporadic Alzheimer's disease (AD). Amnestic mild cognitive impairment (aMCI) is an intermediate state between normal cognitive aging and dementia, which is easy to convert to AD dementia. It is an urgent problem in the field of cognitive neuroscience to reveal the conversion of aMCI-ε4 to AD. Based on our preliminary work, we will study the neuroimaging features in the special group of aMCI-ε4 with multi-modality magnetic resonance imaging (structural MRI, resting state-fMRI and diffusion tensor imaging) longitudinally. In this study, 200 right-handed subjects who are diagnosed as aMCI with APOE-ε4 will be recruited at the memory clinic of the Neurology Department, XuanWu Hospital, Capital Medical University, Beijing, China. All subjects will undergo the neuroimaging and neuropsychological evaluation at a 1 year-interval for 3 years. The primary outcome measures are 1) Microstructural alterations revealed with multimodal MRI scans including structure MRI (sMRI), resting state functional MRI (rs-fMRI), diffusion tensor imaging (DTI); 2) neuropsychological evaluation, including the World Health Organization-University of California-LosAngeles Auditory Verbal Learning Test (WHO-UCLA AVLT), Addenbrook's cognitive examination-revised (ACE-R), mini-mental state examination (MMSE), Montreal Cognitive Assessment (MoCA), Clinical Dementia Rating scale (CDR). This study is to find out the neuroimaging biomarker and the changing laws of the marker during the progress of aMCI-ε4 to AD, and the final purpose is to provide scientific evidence for new prevention, diagnosis and treatment of AD. This study has been registered to ClinicalTrials.gov (NCT02225964, https://www.clinicaltrials.gov/ ) in August 24, 2014.

The Genetics of Endophenotypes of Neurofunction to Understand Schizophrenia (GENUS) consortium: A collaborative cognitive and neuroimaging genetics project.

PubMed

Blokland, Gabriëlla A M; Del Re, Elisabetta C; Mesholam-Gately, Raquelle I; Jovicich, Jorge; Trampush, Joey W; Keshavan, Matcheri S; DeLisi, Lynn E; Walters, James T R; Turner, Jessica A; Malhotra, Anil K; Lencz, Todd; Shenton, Martha E; Voineskos, Aristotle N; Rujescu, Dan; Giegling, Ina; Kahn, René S; Roffman, Joshua L; Holt, Daphne J; Ehrlich, Stefan; Kikinis, Zora; Dazzan, Paola; Murray, Robin M; Di Forti, Marta; Lee, Jimmy; Sim, Kang; Lam, Max; Wolthusen, Rick P F; de Zwarte, Sonja M C; Walton, Esther; Cosgrove, Donna; Kelly, Sinead; Maleki, Nasim; Osiecki, Lisa; Picchioni, Marco M; Bramon, Elvira; Russo, Manuela; David, Anthony S; Mondelli, Valeria; Reinders, Antje A T S; Falcone, M Aurora; Hartmann, Annette M; Konte, Bettina; Morris, Derek W; Gill, Michael; Corvin, Aiden P; Cahn, Wiepke; Ho, New Fei; Liu, Jian Jun; Keefe, Richard S E; Gollub, Randy L; Manoach, Dara S; Calhoun, Vince D; Schulz, S Charles; Sponheim, Scott R; Goff, Donald C; Buka, Stephen L; Cherkerzian, Sara; Thermenos, Heidi W; Kubicki, Marek; Nestor, Paul G; Dickie, Erin W; Vassos, Evangelos; Ciufolini, Simone; Reis Marques, Tiago; Crossley, Nicolas A; Purcell, Shaun M; Smoller, Jordan W; van Haren, Neeltje E M; Toulopoulou, Timothea; Donohoe, Gary; Goldstein, Jill M; Seidman, Larry J; McCarley, Robert W; Petryshen, Tracey L

2018-05-01

Schizophrenia has a large genetic component, and the pathways from genes to illness manifestation are beginning to be identified. The Genetics of Endophenotypes of Neurofunction to Understand Schizophrenia (GENUS) Consortium aims to clarify the role of genetic variation in brain abnormalities underlying schizophrenia. This article describes the GENUS Consortium sample collection. We identified existing samples collected for schizophrenia studies consisting of patients, controls, and/or individuals at familial high-risk (FHR) for schizophrenia. Samples had single nucleotide polymorphism (SNP) array data or genomic DNA, clinical and demographic data, and neuropsychological and/or brain magnetic resonance imaging (MRI) data. Data were subjected to quality control procedures at a central site. Sixteen research groups contributed data from 5199 psychosis patients, 4877 controls, and 725 FHR individuals. All participants have relevant demographic data and all patients have relevant clinical data. The sex ratio is 56.5% male and 43.5% female. Significant differences exist between diagnostic groups for premorbid and current IQ (both p<1×10 -10 ). Data from a diversity of neuropsychological tests are available for 92% of participants, and 30% have structural MRI scans (half also have diffusion-weighted MRI scans). SNP data are available for 76% of participants. The ancestry composition is 70% European, 20% East Asian, 7% African, and 3% other. The Consortium is investigating the genetic contribution to brain phenotypes in a schizophrenia sample collection of >10,000 participants. The breadth of data across clinical, genetic, neuropsychological, and MRI modalities provides an important opportunity for elucidating the genetic basis of neural processes underlying schizophrenia. Copyright © 2017 Elsevier B.V. All rights reserved.

Efficacy of navigation may be influenced by retrosplenial cortex-mediated learning of landmark stability.

PubMed

Auger, Stephen D; Zeidman, Peter; Maguire, Eleanor A

2017-09-01

Human beings differ considerably in their ability to orient and navigate within the environment, but it has been difficult to determine specific causes of these individual differences. Permanent, stable landmarks are thought to be crucial for building a mental representation of an environment. Poor, compared to good, navigators have been shown to have difficulty identifying permanent landmarks, with a concomitant reduction in functional MRI (fMRI) activity in the retrosplenial cortex. However, a clear association between navigation ability and the learning of permanent landmarks has not been established. Here we tested for such a link. We had participants learn a virtual reality environment by repeatedly moving through it during fMRI scanning. The environment contained landmarks of which participants had no prior experience, some of which remained fixed in their locations while others changed position each time they were seen. After the fMRI learning phase, we divided participants into good and poor navigators based on their ability to find their way in the environment. The groups were closely matched on a range of cognitive and structural brain measures. Examination of the learning phase during scanning revealed that, while good and poor navigators learned to recognise the environment's landmarks at a similar rate, poor navigators were impaired at registering whether landmarks were stable or transient, and this was associated with reduced engagement of the retrosplenial cortex. Moreover, a mediation analysis showed that there was a significant effect of landmark permanence learning on navigation performance mediated through retrosplenial cortex activity. We conclude that a diminished ability to process landmark permanence may be a contributory factor to sub-optimal navigation, and could be related to the level of retrosplenial cortex engagement. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

SU-F-J-166: Volumetric Spatial Distortions Comparison for 1.5 Tesla Versus 3 Tesla MRI for Gamma Knife Radiosurgery Scans Using Frame Marker Fusion and Co-Registration Modes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neyman, G

Purpose: To compare typical volumetric spatial distortions for 1.5 Tesla versus 3 Tesla MRI Gamma Knife radiosurgery scans in the frame marker fusion and co-registration frame-less modes. Methods: Quasar phantom by Modus Medical Devices Inc. with GRID image distortion software was used for measurements of volumetric distortions. 3D volumetric T1 weighted scans of the phantom were produced on 1.5 T Avanto and 3 T Skyra MRI Siemens scanners. The analysis was done two ways: for scans with localizer markers from the Leksell frame and relatively to the phantom only (simulated co-registration technique). The phantom grid contained a total of 2002more » vertices or control points that were used in the assessment of volumetric geometric distortion for all scans. Results: Volumetric mean absolute spatial deviations relatively to the frame localizer markers for 1.5 and 3 Tesla machine were: 1.39 ± 0.15 and 1.63 ± 0.28 mm with max errors of 1.86 and 2.65 mm correspondingly. Mean 2D errors from the Gamma Plan were 0.3 and 1.0 mm. For simulated co-registration technique the volumetric mean absolute spatial deviations relatively to the phantom for 1.5 and 3 Tesla machine were: 0.36 ± 0.08 and 0.62 ± 0.13 mm with max errors of 0.57 and 1.22 mm correspondingly. Conclusion: Volumetric spatial distortions are lower for 1.5 Tesla versus 3 Tesla MRI machines localized with markers on frames and significantly lower for co-registration techniques with no frame localization. The results show the advantage of using co-registration technique for minimizing MRI volumetric spatial distortions which can be especially important for steep dose gradient fields typically used in Gamma Knife radiosurgery. Consultant for Elekta AB.« less

Cerebral gray matter volume in patients with chronic migraine: correlations with clinical features.

PubMed

Coppola, Gianluca; Petolicchio, Barbara; Di Renzo, Antonio; Tinelli, Emanuele; Di Lorenzo, Cherubino; Parisi, Vincenzo; Serrao, Mariano; Calistri, Valentina; Tardioli, Stefano; Cartocci, Gaia; Ambrosini, Anna; Caramia, Francesca; Di Piero, Vittorio; Pierelli, Francesco

2017-12-08

To date, few MRI studies have been performed in patients affected by chronic migraine (CM), especially in those without medication overuse. Here, we performed magnetic resonance imaging (MRI) voxel-based morphometry (VBM) analyses to investigate the gray matter (GM) volume of the whole brain in patients affected by CM. Our aim was to investigate whether fluctuations in the GM volumes were related to the clinical features of CM. Twenty untreated patients with CM without a past medical history of medication overuse underwent 3-Tesla MRI scans and were compared to a group of 20 healthy controls (HCs). We used SPM12 and the CAT12 toolbox to process the MRI data and to perform VBM analyses of the structural T1-weighted MRI scans. The GM volume of patients was compared to that of HCs with various corrected and uncorrected thresholds. To check for possible correlations, patients' clinical features and GM maps were regressed. Initially, we did not find significant differences in the GM volume between patients with CM and HCs (p < 0.05 corrected for multiple comparisons). However, using more-liberal uncorrected statistical thresholds, we noted that compared to HCs, patients with CM exhibited clusters of regions with lower GM volumes including the cerebellum, left middle temporal gyrus, left temporal pole/amygdala/hippocampus/pallidum/orbitofrontal cortex, and left occipital areas (Brodmann areas 17/18). The GM volume of the cerebellar hemispheres was negatively correlated with the disease duration and positively correlated with the number of tablets taken per month. No gross morphometric changes were observed in patients with CM when compared with HCs. However, using more-liberal uncorrected statistical thresholds, we observed that CM is associated with subtle GM volume changes in several brain areas known to be involved in nociception/antinociception, multisensory integration, and analgesic dependence. We speculate that these slight morphometric impairments could lead, at least in a subgroup of patients, to the development and continuation of maladaptive acute medication usage.

Whole body sodium MRI at 3T using an asymmetric birdcage resonator and short echo time sequence: first images of a male volunteer

NASA Astrophysics Data System (ADS)

Wetterling, Friedrich; Corteville, Dominique M.; Kalayciyan, Raffi; Rennings, Andreas; Konstandin, Simon; Nagel, Armin M.; Stark, Helmut; Schad, Lothar R.

2012-07-01

Sodium magnetic resonance imaging (23Na MRI) is a non-invasive technique which allows spatial resolution of the tissue sodium concentration (TSC) in the human body. TSC measurements could potentially serve to monitor early treatment success of chemotherapy on patients who suffer from whole body metastases. Yet, the acquisition of whole body sodium (23Na) images has been hampered so far by the lack of large resonators and the extremely low signal-to-noise ratio (SNR) achieved with existing resonator systems. In this study, a 23Na resonator was constructed for whole body 23Na MRI at 3T comprising of a 16-leg, asymmetrical birdcage structure with 34 cm height, 47.5 cm width and 50 cm length. The resonator was driven in quadrature mode and could be used either as a transceiver resonator or, since active decoupling was included, as a transmit-only resonator in conjunction with a receive-only (RO) surface resonator. The relative B1-field profile was simulated and measured on phantoms, and 3D whole body 23Na MRI data of a healthy male volunteer were acquired in five segments with a nominal isotropic resolution of (6 × 6 × 6) mm3 and a 10 min acquisition time per scan. The measured SNR values in the 23Na-MR images varied from 9 ± 2 in calf muscle, 15 ± 2 in brain tissue, 23 ± 2 in the prostate and up to 42 ± 5 in the vertebral discs. Arms, legs, knees and hands could also be resolved with applied resonator and short time-to-echo (TE) (0.5 ms) radial sequence. Up to fivefold SNR improvement was achieved through combining the birdcage with local RO surface coil. In conclusion, 23Na MRI of the entire human body provides sub-cm spatial resolution, which allows resolution of all major human body parts with a scan time of less than 60 min.

High resolution MRI imaging at 9.4 Tesla of the osteochondral unit in a translational model of articular cartilage repair.

PubMed

Goebel, Lars; Müller, Andreas; Bücker, Arno; Madry, Henning

2015-04-16

Non-destructive structural evaluation of the osteochondral unit is challenging. Here, the capability of high-field magnetic resonance imaging (μMRI) at 9.4 Tesla (T) was explored to examine osteochondral repair ex vivo in a preclinical large animal model. A specific aim of this study was to detect recently described alterations of the subchondral bone associated with cartilage repair. Osteochondral samples of medial femoral condyles from adult ewes containing full-thickness articular cartilage defects treated with marrow stimulation were obtained after 6 month in vivo and scanned in a 9.4 T μMRI. Ex vivo imaging of small osteochondral samples (typical volume: 1-2 cm(3)) at μMRI was optimised by variation of repetition time (TR), time echo (TE), flip angle (FA), spatial resolution and number of excitations (NEX) from standard MultiSliceMultiEcho (MSME) and three-dimensional (3D) spoiled GradientEcho (SGE) sequences. A 3D SGE sequence with the parameters: TR = 10 ms, TE = 3 ms, FA = 10°, voxel size = 120 × 120 × 120 μm(3) and NEX = 10 resulted in the best fitting for sample size, image quality, scanning time and artifacts. An isovolumetric voxel shape allowed for multiplanar reconstructions. Within the osteochondral unit articular cartilage, cartilaginous repair tissue and bone marrow could clearly be distinguished from the subchondral bone plate and subarticular spongiosa. Specific alterations of the osteochondral unit associated with cartilage repair such as persistent drill holes, subchondral bone cysts, sclerosis of the subchondral bone plate and of the subarticular spongiosa and intralesional osteophytes were precisely detected. High resolution, non-destructive ex vivo analysis of the entire osteochondral unit in a preclinical large animal model that is sufficient for further analyses is possible using μMRI at 9.4 T. In particular, 9.4 T is capable of accurately depicting alterations of the subchondral bone that are associated with osteochondral repair.

[Comparison of magnetic resonance imaging artifacts of five common dental materials].

PubMed

Xu, Yisheng; Yu, Risheng

2015-06-01

To compare five materials commonly used in dentistry, including three types of metals and two types of ceramics, by using different sequences of three magnetic resonance imaging (MRI) field strengths (0.35, 1.5, and 3.0 T). Three types of metals and two types of ceramics that were fabricated into the same size and thickness as an incisor crown were placed in a plastic tank filled with saline. The crowns were scanned using an magnetic resonance (MR) machine at 0.35, 1.5, and 3.0 T field strengths. The TlWI and T2WI images were obtained. The differences of various materials in different artifacts of field MR scans were determined. The zirconia crown presented no significant artifacts when scanned under the three types of MRI field strengths. The artifacts of casting ceramic were minimal. All dental precious metal alloys, nickel-chromium alloy dental porcelain, and cobalt-chromium ceramic alloy showed varying degrees of artifacts under the three MRI field strengths. Zirconia and casting ceramics present almost no or faint artifacts. By contrast, precious metal alloys, nickel-chromium alloy dental porcelain and cobalt-chromium ceramic alloy display MRI artifacts. The artifact area increase with increasing magnetic field.

SU-G-IeP4-11: Monitoring Tumor Growth in Subcutaneous Murine Tumor Model in Vivo: A Comparison Between MRI and Small Animal CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, B; He, W; Cvetkovic, D

Purpose: The purpose of the study is to compare the volume measurement of subcutaneous tumors in mice with different imaging platforms, namely a GE MRI and a Sofie-Biosciences small animal CT scanner. Methods: A549 human lung carcinoma cells and FaDu human head and neck squamous cell carcinoma cells were implanted subcutaneously into flanks of nude mice. Three FaDu tumors and three A549 tumors were included in this study. The MRI scans were done with a GE Signa 1.5 Tesla MR scanner using a fast T2-weighted sequence (70mm FOV and 1.2mm slice thickness), while the CT scans were done with themore » CT scanner on a Sofie-Biosciences G8 PET/CT platform dedicated for small animal studies (48mm FOV and 0.2mm slice thickness). Imaging contrast agent was not used in this study. Based on the DICOM images from MRI and CT scans, the tumors were contoured with Philips DICOM Viewer and the tumor volumes were obtained by summing up the contoured area and multiplied by the slice thickness. Results: The volume measurements based on the CT scans agree reasonably with that obtained with MR images for the subcutaneous tumors. The mean difference in the absolute tumor volumes between MRI- and CT-based measurements was found to be −6.2% ± 1.0%, with the difference defined as (VMR – VCT)*100%/VMR. Furthermore, we evaluated the normalized tumor volumes, which were defined for each tumor as V/V{sub 0} where V{sub 0} stands for the volume from the first MR or CT scan. The mean difference in the normalized tumor volumes was found to be 0.10% ± 0.96%. Conclusion: Despite the fact that the difference between normal and abnormal tissues is often less clear on small animal CT images than on MR images, one can still obtain reasonable tumor volume information with the small animal CT scans for subcutaneous murine xenograft models.« less

Dobutamine stress magnetic resonance imaging: a valuable method in the noninvasive diagnosis of ischemic heart disease.

PubMed

van Dijkman, Paul R M; Kuijpers, Dirkjan A; Blom, Bernadette M; van Herpen, Gerard

2002-01-01

We assessed the clinical applicability of dobutamine stress magnetic resonance imaging (DS-MRI) for the detection of myocardial ischemia and myocardial viability. One hundred patients with suspected coronary artery disease and inconclusive exercise electrocardiography or significant repolarization abnormalities on the resting ECG underwent breath hold DS-MRI (1 Tesla), 4 days after cessation of anti-ischemic medication. Three left ventricular short axis planes were imaged at increasing doses of dobutamine. Recovery of wall thickening in a previously diminished or non contracting segment at low dose dobutamine was considered proof of viability. Development of hypo-, a- or dyskinesia at higher doses of dobutamine was taken to indicate ischemia. If the DS-MRI test was positive for ischemia, coronary angiography was performed. If indicated, this was followed by revascularization. If DS-MRI did not demonstrate ischemia, neither angiography nor revascularization were carried out. Ninety five DS-MRI investigations were available for diagnosis. Forty two patients had DS-MRI scans positive for ischemia and subsequently coronary angiography assessment of the clinical applicability of DS-MRI for the detection of myocardial ischemia was performed. One patient was false-positive. All 53 patients with non-ischemic DS-MRI scans had follow-up for 11-23 months (mean 17 months). One patient died suddenly 2 weeks after the MRI-test. The other 52 patients did not experience any coronary event nor sudden cardiac death. The predictive value of a positive (for ischemia) DS-MRI test is 98% and the predictive value of a negative DS-MRI test is also 98%.

Music-based magnetic resonance fingerprinting to improve patient comfort during MRI examinations.

PubMed

Ma, Dan; Pierre, Eric Y; Jiang, Yun; Schluchter, Mark D; Setsompop, Kawin; Gulani, Vikas; Griswold, Mark A

2016-06-01

Unpleasant acoustic noise is a drawback of almost every MRI scan. Instead of reducing acoustic noise to improve patient comfort, we propose a technique for mitigating the noise problem by producing musical sounds directly from the switching magnetic fields while simultaneously quantifying multiple important tissue properties. MP3 music files were converted to arbitrary encoding gradients, which were then used with varying flip angles and repetition times in a two- and three-dimensional magnetic resonance fingerprinting (MRF) examination. This new acquisition method, named MRF-Music, was used to quantify T1 , T2 , and proton density maps simultaneously while providing pleasing sounds to the patients. MRF-Music scans improved patient comfort significantly during MRI examinations. The T1 and T2 values measured from phantom are in good agreement with those from the standard spin echo measurements. T1 and T2 values from the brain scan are also close to previously reported values. MRF-Music sequence provides significant improvement in patient comfort compared with the MRF scan and other fast imaging techniques such as echo planar imaging and turbo spin echo scans. It is also a fast and accurate quantitative method that quantifies multiple relaxation parameters simultaneously. Magn Reson Med 75:2303-2314, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Repeated diffusion MRI reveals earliest time point for stratification of radiotherapy response in brain metastases

NASA Astrophysics Data System (ADS)

Mahmood, Faisal; Johannesen, Helle H.; Geertsen, Poul; Hansen, Rasmus H.

2017-04-01

An imaging biomarker for early prediction of treatment response potentially provides a non-invasive tool for better prognostics and individualized management of the disease. Radiotherapy (RT) response is generally related to changes in gross tumor volume manifesting months later. In this prospective study we investigated the apparent diffusion coefficient (ADC), perfusion fraction and pseudo diffusion coefficient derived from diffusion weighted MRI as potential early biomarkers for radiotherapy response of brain metastases. It was a particular aim to assess the optimal time point for acquiring the DW-MRI scan during the course of treatment, since to our knowledge this important question has not been addressed directly in previous studies. Twenty-nine metastases (N  =  29) from twenty-one patients, treated with whole-brain fractionated external beam RT were analyzed. Patients were scanned with a 1 T MRI system to acquire DW-, T2*W-, T2W- and T1W scans, before start of RT, at each fraction and at follow up two to three months after RT. The DW-MRI parameters were derived using regions of interest based on high b-value images (b  =  800 s mm-2). Both volumetric and RECIST criteria were applied for response evaluation. It was found that in non-responding metastases the mean ADC decreased and in responding metastases it increased. The volume based response proved to be far more consistently predictable by the ADC change found at fraction number 7 and later, compared to the linear response (RECIST). The perfusion fraction and pseudo diffusion coefficient did not show sufficient prognostic value with either response assessment criteria. In conclusion this study shows that the ADC derived using high b-values may be a reliable biomarker for early assessment of radiotherapy response for brain metastases patients. The earliest response stratification can be achieved using two DW-MRI scans, one pre-treatment and one at treatment day 7-9 (equivalent to 21 Gy).

Nanotechnology and cancer: improving real-time monitoring and staging of bladder cancer with multimodal mesoporous silica nanoparticles.

PubMed

Sweeney, Sean K; Luo, Yi; O'Donnell, Michael A; Assouline, Jose

Despite being one of the most common cancers, bladder cancer is largely inefficiently and inaccurately staged and monitored. Current imaging methods detect cancer only when it has reached "visible" size and has significantly disrupted the structure of the organ. By that time, thousands of cells will have proliferated and perhaps metastasized. Repeated biopsies and scans are necessary to determine the effect of therapy on cancer growth. In this report, we describe a novel approach based on multimodal nanoparticle contrast agent technology and its application to a preclinical animal model of bladder cancer. The innovation relies on the engineering core of mesoporous silica with specific scanning contrast properties and surface modification that include fluorescence and magnetic resonance imaging (MRI) contrast. The overall dimensions of the nano-device are preset at 80-180 nm, depending on composition with a pore size of 2 nm. To facilitate and expedite discoveries, we combined a well-known model of bladder cancer and our novel technology. We exposed nanoparticles to MB49 murine bladder cancer cells in vitro and found that 70 % of the cells were labeled by nanoparticles as measured by flow cytometry. The in vivo mouse model for bladder cancer is particularly well suited for T1- and T2-weighted MRI. Under our experimental conditions, we demonstrate that the nanoparticles considerably improve tumor definition in terms of volumetric, intensity and structural characteristics. Important bladder tumor parameters can be ascertained, non-invasively, repetitively, and with great accuracy. Furthermore, since the particles are not biodegradable, repetitive injection is not required. This feature allows follow-up diagnostic evaluations during cancer treatment. Changes in MRI signals show that in situ uptake of free particles has predilection to tumor cells relative to normal bladder epithelium. The particle distribution within the tumors was corroborated by fluorescent microscopy of sections of excised bladders. In addition, MRI imaging revealed fibrous finger-like projections into the tumors where particles insinuated themselves deeply. This morphological characteristic was confirmed by fluorescence microscopy. These findings may present new options for therapeutic intervention. Ultimately, the combination of real-time and repeated MRI evaluation of the tumors enhanced by nanoparticle contrast may have the potential for translation into human clinical studies for tumor staging, therapeutic monitoring, and drug delivery.

SU-E-J-153: MRI Based, Daily Adaptive Radiotherapy for Rectal Cancer: Contour Adaptation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kleijnen, J; Burbach, M; Verbraeken, T

2014-06-01

Purpose: A major hurdle in adaptive radiotherapy is the adaptation of the planning MRI's delineations to the daily anatomy. We therefore investigate the accuracy and time needed for online clinical target volume (CTV) adaptation by radiation therapists (RTT), to be used in MRI-guided adaptive treatments on a MRI-Linac (MRL). Methods: Sixteen patients, diagnosed with early stage rectal cancer, underwent a T2-weighted MRI prior to each fraction of short-course radiotherapy, resulting in 4–5 scans per patient. On these scans, the CTV was delineated according to guidelines by an experienced radiation oncologist (RO) and considered to be the gold standard. For eachmore » patient, the first MRI was considered as the planning MRI and matched on bony anatomy to the 3–4 daily MRIs. The planning MRI's CTV delineation was rigidly propagated to the daily MRI scans as a proposal for adaptation. Three RTTs in training started the adaptation of the CTV conform guidelines, after a two hour training lecture and a two patient (n=7) training set. To assess the inter-therapist variation, all three RTTs altered delineations of 3 patients (n=12). One RTT altered the CTV delineations (n=53) of the remaining 11 patients. Time needed for adaptation of the CTV to guidelines was registered.As a measure of agreement, the conformity index (CI) was determined between the RTTs' delineations as a group. Dice similarity coefficients were determined between delineations of the RTT and the RO. Results: We found good agreement between RTTs' and RO's delineations (average Dice=0.91, SD=0.03). Furthermore, the inter-observer agreement between the RTTs was high (average CI=0.94, SD=0.02). Adaptation time reduced from 10:33 min (SD= 3:46) to 2:56 min (SD=1:06) between the first and last ten delineations, respectively. Conclusion: Daily CTV adaptation by RTTs, seems a feasible and safe way to introduce daily, online MRI-based plan adaptation for a MRL.« less

Gray matter volume is associated with rate of subsequent skill learning after a long term training intervention

PubMed Central

Sampaio-Baptista, Cassandra; Scholz, Jan; Jenkinson, Mark; Thomas, Adam G.; Filippini, Nicola; Smit, Gabrielle; Douaud, Gwenaëlle; Johansen-Berg, Heidi

2014-01-01

The ability to predict learning performance from brain imaging data has implications for selecting individuals for training or rehabilitation interventions. Here, we used structural MRI to test whether baseline variations in gray matter (GM) volume correlated with subsequent performance after a long-term training of a complex whole-body task. 44 naïve participants were scanned before undertaking daily juggling practice for 6 weeks, following either a high intensity or a low intensity training regime. To assess performance across the training period participants' practice sessions were filmed. Greater GM volume in medial occipito-parietal areas at baseline correlated with steeper learning slopes. We also tested whether practice time or performance outcomes modulated the degree of structural brain change detected between the baseline scan and additional scans performed immediately after training and following a further 4 weeks without training. Participants with better performance had higher increases in GM volume during the period following training (i.e., between scans 2 and 3) in dorsal parietal cortex and M1. When contrasting brain changes between the practice intensity groups, we did not find any straightforward effects of practice time though practice modulated the relationship between performance and GM volume change in dorsolateral prefrontal cortex. These results suggest that practice time and performance modulate the degree of structural brain change evoked by long-term training regimes. PMID:24680712

Vestibular Balance Deficits Following Head Injury: Recommendations Concerning Evaluation and Rehabilitation in the Military Setting

DTIC Science & Technology

2012-02-27

audiogram, magnetic resonance imaging ( MRI ) scan, and a battery of neuro-vestibular tests, etc. (see appendix B). Many of the findings are detailed...bills108/s1217.html 19 E.g., driven by a laptop, tablet PC, or PDA.   42 The authors also considered testing needs immediately after referral (by the... MRI scan   72 Neuro-vestibular testing o Dynamic Computerized Postu rography o Rotat ional chair t est ing of gain, phase, and symmet ry o Step

Organophosphate-Related Alterations in Myelin and Axonal Transport in the Living Mammalian Brain

DTIC Science & Technology

2013-10-01

chlorpyrifos (CPF), and a representative, nerve agent, diisopropylfluorophosphate (DFP) in rats. The first year of this proposal has been dedicated...to date (N=4-6): 1) baseline MRI scans; 2) daily injections of vehicle or chlorpyrifos (3.0-18.0 mg/kg) x 14 days; 2) a second MRI scan on the day...affected individuals. We are studying two OPs, a representative insecticide that was used in the first gulf war, chlorpyrifos (CPF), and a

A Unified Framework for Brain Segmentation in MR Images

PubMed Central

Yazdani, S.; Yusof, R.; Karimian, A.; Riazi, A. H.; Bennamoun, M.

2015-01-01

Brain MRI segmentation is an important issue for discovering the brain structure and diagnosis of subtle anatomical changes in different brain diseases. However, due to several artifacts brain tissue segmentation remains a challenging task. The aim of this paper is to improve the automatic segmentation of brain into gray matter, white matter, and cerebrospinal fluid in magnetic resonance images (MRI). We proposed an automatic hybrid image segmentation method that integrates the modified statistical expectation-maximization (EM) method and the spatial information combined with support vector machine (SVM). The combined method has more accurate results than what can be achieved with its individual techniques that is demonstrated through experiments on both real data and simulated images. Experiments are carried out on both synthetic and real MRI. The results of proposed technique are evaluated against manual segmentation results and other methods based on real T1-weighted scans from Internet Brain Segmentation Repository (IBSR) and simulated images from BrainWeb. The Kappa index is calculated to assess the performance of the proposed framework relative to the ground truth and expert segmentations. The results demonstrate that the proposed combined method has satisfactory results on both simulated MRI and real brain datasets. PMID:26089978

Comparison of CT and MRI in diagnosis of cerebrospinal leak induced by multiple fractures of skull base

PubMed Central

Wang, Xuhui; Xu, Minhui; Liang, Hong; Xu, Lunshan

2011-01-01

Background Multiple basilar skull fracture and cerebrospinal leak are common complications of traumatic brain injury, which required a surgical repair. But due to the complexity of basilar skull fracture after severe trauma, preoperatively an exact radiological location is always difficult. Multi-row spiral CT and MRI are currently widely applied in the clinical diagnosis. The present study was performed to compare the accuracy of cisternography by multi-row spiral CT and MRI in the diagnosis of cerebrospinal leak. Methods A total of 23 patients with multiple basilar skull fracture after traumatic brain injury were included. The radiological and surgical data were retrospectively analyzed. 64-row CT (mm/row) scan and three-dimensional reconstruction were performed in 12 patients, while MR plain scan and cisternography were performed in another 11 patients. The location of cerebrospinal leak was diagnosed by 2 experienced physicians majoring neurological radiology. Surgery was performed in all patients. The cerebrospinal leak location was confirmed and repaired during surgery. The result was considered as accurate when cerebrospinal leak was absent after surgery. Results According to the surgical exploration, the preoperative diagnosis of the active cerebrospinal leak location was accurate in 9 out of 12 patients with CT scan. The location could not be confirmed by CT because of multiple fractures in 2 patients and the missed diagnosis occurred in 1 patient. The preoperative diagnosis was accurate in 10 out of 11 patients with MRI examination. Conclusions MRI cisternography is more advanced than multi-row CT scan in multiple basilar skull fracture. The combination of the two examinations may increase the diagnostic ratio of active cerebrospinal leak. PMID:22933941

Utility of Early Post-operative High Resolution Volumetric MR Imaging after Transsphenoidal Pituitary Tumor Surgery

PubMed Central

Patel, Kunal S.; Kazam, Jacob; Tsiouris, Apostolos J.; Anand, Vijay K.; Schwartz, Theodore H.

2014-01-01

Objective Controversy exists over the utility of early post-operative magnetic resonance imaging (MRI) after transsphenoidal pituitary surgery for macroadenomas. We investigate whether valuable information can be derived from current higher resolution scans. Methods Volumetric MRI scans were obtained in the early (<10 days) and late (>30 days) post-operative periods in a series of patients undergoing transsphenoidal pituitary surgery. The volume of the residual tumor, resection cavity, and corresponding visual field tests were recorded at each time point. Statistical analyses of changes in tumor volume and cavity size were calculated using the late MRI as the gold standard. Results 40 patients met the inclusion criteria. Pre-operative tumor volume averaged 8.8 cm3. Early postoperative assessment of average residual tumor volume (1.18 cm3) was quite accurate and did not differ statistically from late post-operative volume (1.23 cm3, p=.64), indicating the utility of early scans to measure residual tumor. Early scans were 100% sensitive and 91% specific for predicting ≥ 98% resection (p<.001, Fisher’s exact test). The average percent decrease in cavity volume from pre-operative MRI (tumor volume) to early post-operative imaging was 45% with decreases in all but 3 patients. There was no correlation between the size of the early cavity and the visual outcome. Conclusions Early high resolution volumetric MRI is valuable in determining the presence or absence of residual tumor. Cavity volume almost always decreases after surgery and a lack of decrease should alert the surgeon to possible persistent compression of the optic apparatus that may warrant re-operation. PMID:25045791

Interobserver variability in the radiological assessment of magnetic resonance imaging (MRI) including perfusion MRI in glioblastoma multiforme.

PubMed

Kerkhof, M; Hagenbeek, R E; van der Kallen, B F W; Lycklama À Nijeholt, G J; Dirven, L; Taphoorn, M J B; Vos, M J

2016-10-01

Conventional magnetic resonance imaging (MRI) has limited value for differentiation of true tumor progression and pseudoprogression in treated glioblastoma multiforme (GBM). Perfusion weighted imaging (PWI) may be helpful in the differentiation of these two phenomena. Here interobserver variability in routine radiological evaluation of GBM patients is assessed using MRI, including PWI. Three experienced neuroradiologists evaluated MR scans of 28 GBM patients during temozolomide chemoradiotherapy at three time points: preoperative (MR1) and postoperative (MR2) MR scan and the follow-up MR scan after three cycles of adjuvant temozolomide (MR3). Tumor size was measured both on T1 post-contrast and T2 weighted images according to the Response Assessment in Neuro-Oncology criteria. PW images of MR3 were evaluated by visual inspection of relative cerebral blood volume (rCBV) color maps and by quantitative rCBV measurements of enhancing areas with highest rCBV. Image interpretability of PW images was also scored. Finally, the neuroradiologists gave a conclusion on tumor status, based on the interpretation of both T1 and T2 weighted images (MR1, MR2 and MR3) in combination with PWI (MR3). Interobserver agreement on visual interpretation of rCBV maps was good (κ = 0.63) but poor on quantitative rCBV measurements and on interpretability of perfusion images (intraclass correlation coefficient 0.37 and κ = 0.23, respectively). Interobserver agreement on the overall conclusion of tumor status was moderate (κ = 0.48). Interobserver agreement on the visual interpretation of PWI color maps was good. However, overall interpretation of MR scans (using both conventional and PW images) showed considerable interobserver variability. Therefore, caution should be applied when interpreting MRI results during chemoradiation therapy. © 2016 EAN.

Increased frequency of brain pathology in inmates of a high-security forensic institution: a qualitative CT and MRI scan study.

PubMed

Witzel, Joachim G; Bogerts, Bernhard; Schiltz, Kolja

2016-09-01

This study aimed to assess whether brain pathology might be more abundant in forensic inpatients in a high-security setting than in non-criminal individuals. By using a previously used reliable approach, we explored the frequency and extent of brain pathology in a large group of institutionalized offenders who had not previously been considered to be suffering from structural brain damage and compare it to healthy, non-offending subjects. MRI and CT brain scans from 148 male inpatients of a high-security mental health institution (offense type: 51 sex, 80 violent, 9 arson, and 8 nonviolent) that were obtained due to headache, vertigo, or psychological complaints during imprisonment were assessed and compared to 52 non-criminal healthy controls. Brain scans were assessed qualitatively with respect to evidence of structural brain damage. Each case received a semiquantitative rating of "normal" (=0), "questionably abnormal" (=1), or "definitely abnormal" (=2) for the lateral ventricles, frontal/parietal cortex, and medial temporal structures bilaterally as well as third ventricle. Forensic inpatients displayed signs of brain damage to a significantly higher degree than healthy controls (p < 0.001). Even after adjustment for age, in the patients, being younger than the controls (p < 0.05), every offender type group displayed a higher proportion of subjects with brain regions categorized as definitely abnormal than the non-criminal controls. Within the forensic inpatients, offense type groups did not significantly differ in brain pathology. The astonishingly high prevalence of brain pathology in institutionalized inmates of a high-security mental health institution who previously had not been considered to be suffering from an organic brain syndrome raises questions on whether such neuroradiological assessment might be considered as a routine procedure in newly admitted patients. Furthermore, it highlights that organic changes, detectable under clinical routine conditions, may play a role in the development of legally relevant behavioral disturbances which might be underestimated.

A case study of magnetic resonance imaging of cerebrovascular reactivity: a powerful imaging marker for mild traumatic brain injury.

PubMed

Chan, Suk-tak; Evans, Karleyton C; Rosen, Bruce R; Song, Tian-yue; Kwong, Kenneth K

2015-01-01

To use breath-hold functional magnetic resonance imaging (fMRI) to localize the brain regions with impaired cerebrovascular reactivity (CVR) in a female patient diagnosed with mild traumatic brain injury (mTBI). The extent of impaired CVR was evaluated 2 months after concussion. Follow-up scan was performed 1 year post-mTBI using the same breath-hold fMRI technique. Case report. fMRI blood oxygenation dependent level (BOLD) signals were measured under breath-hold challenge in a female mTBI patient 2 months after concussion followed by a second fMRI with breath-hold challenge 1 year later. CVR was expressed as the percentage change of BOLD signals per unit time of breath-hold. In comparison with CVR measurement of normal control subjects, statistical maps of CVR revealed substantial neurovascular deficits and hemispheric asymmetry within grey and white matter in the initial breath-hold fMRI scan. Follow-up breath-hold fMRI performed 1 year post-mTBI demonstrated normalization of CVR accompanied with symptomatic recovery. CVR may serve as an imaging biomarker to detect subtle deficits in both grey and white matter for individual diagnosis of mTBI. The findings encourage further investigation of hypercapnic fMRI as a diagnostic tool for mTBI.

Predictive values of BI-RADS(®) magnetic resonance imaging (MRI) in the detection of breast ductal carcinoma in situ (DCIS).

PubMed

Badan, Gustavo Machado; Piato, Sebastião; Roveda, Décio; de Faria Castro Fleury, Eduardo

2016-10-01

The purpose of this study was to evaluate BI-RADS indicators in the detection of DCIS by MRI. Prospective observational study that started in 2014 and lasted 24 months. A total of 110 consecutive patients were evaluated, who presented with suspicious or highly suspicious microcalcifications on screening mammography (BI-RADS categories 4 and 5) and underwent stereotactic-guided breast biopsy, having had an MRI scan performed prior to biopsy. Altogether, 38 cases were characterized as positive for malignancy, of which 25 were DCIS and 13 were invasive ductal carcinoma cases. MRI had a sensitivity of 96%; specificity of 75.67%; positive predictive value (PPV) for DCIS detection of 57.14%; negative predictive value (NPV) in the detection of DCIS of 98.24%; and an accuracy of 80.80%. BI-RADS as a tool for the detection of DCIS by MRI is a powerful instrument whose sensitivity was higher when compared to that observed for mammography in the literature. Likewise, the PPV obtained by MRI was higher than that observed in the present study for mammography, and the high NPV obtained on MRI scans can provide early evidence to discourage breast biopsy in selected cases. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Postoperative enhancement on breast MRI: Time course and pattern of changes.

PubMed

Mahoney, Mary C; Sharda, Radhika G

2018-04-23

Expected postoperative enhancement on breast MRI can appear similar to enhancement seen in recurrent or residual malignancy. Our aim was to assess the time course and patterns of enhancement at the surgical site, thereby helping to distinguish between benign and malignant postoperative enhancement. In 200 MRI scans performed in 153 patients after breast conservation treatment, 43 after surgical excision of atypia, and 4 patients after benign excisional biopsy were categorized by postoperative time interval. We defined 4 patterns of morphologic enhancement on MRI: cavity wall/seroma (Pattern I); thin linear (Pattern II); mass (Pattern III); and fat necrosis (Pattern IV). Of 200 MRI scans, 66 (33%) demonstrated enhancement at the surgical site. Enhancement typically decreased through the postoperative follow-up period. Enhancement was observed in 41% (28/68) of cases beyond the 18-month interval but was uncommon after 5 years. Pattern III enhancement was the morphologic pattern seen most commonly with malignancy (5/19 cases, 26%). When associated with delayed washout kinetics, it was even more strongly predictive of malignancy (4/5 cases, 80%). In patients with a history of excisional biopsy and no prior radiation treatment, the percentage of MRI scans showing enhancement was significantly lower than (21% vs 49% with P-value .0027) in patients who had undergone radiation. Enhancement at the surgical site occurred in one-third of cases up to 5 years after surgery, particularly in patients who underwent both radiation and surgery. Mass enhancement, particularly in conjunction with delayed washout kinetics, is most predictive of malignancy and should prompt biopsy or re-excision. © 2018 Wiley Periodicals, Inc.

Diagnostic accuracy of susceptibility-weighted magnetic resonance imaging for the evaluation of pineal gland calcification

PubMed Central

Böker, Sarah M.; Bender, Yvonne Y.; Diederichs, Gerd; Fallenberg, Eva M.; Wagner, Moritz; Hamm, Bernd; Makowski, Marcus R.

2017-01-01

Objectives To determine the diagnostic performance of susceptibility-weighted magnetic resonance imaging (SWMR) for the detection of pineal gland calcifications (PGC) compared to conventional magnetic resonance imaging (MRI) sequences, using computed tomography (CT) as a reference standard. Methods 384 patients who received a 1.5 Tesla MRI scan including SWMR sequences and a CT scan of the brain between January 2014 and October 2016 were retrospectively evaluated. 346 patients were included in the analysis, of which 214 showed PGC on CT scans. To assess correlation between imaging modalities, the maximum calcification diameter was used. Sensitivity and specificity and intra- and interobserver reliability were calculated for SWMR and conventional MRI sequences. Results SWMR reached a sensitivity of 95% (95% CI: 91%-97%) and a specificity of 96% (95% CI: 91%-99%) for the detection of PGC, whereas conventional MRI achieved a sensitivity of 43% (95% CI: 36%-50%) and a specificity of 96% (95% CI: 91%-99%). Detection rates for calcifications in SWMR and conventional MRI differed significantly (95% versus 43%, p<0.001). Diameter measurements between SWMR and CT showed a close correlation (R2 = 0.85, p<0.001) with a slight but not significant overestimation of size (SWMR: 6.5 mm ± 2.5; CT: 5.9 mm ± 2.4, p = 0.02). Interobserver-agreement for diameter measurements was excellent on SWMR (ICC = 0.984, p < 0.0001). Conclusions Combining SWMR magnitude and phase information enables the accurate detection of PGC and offers a better diagnostic performance than conventional MRI with CT as a reference standard. PMID:28278291

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voroney, Jon-Paul; Brock, Kristy K.; Eccles, Cynthia

Purpose: The aim of this study was to compare magnetic resonance imaging (MRI) with computed tomography (CT) for liver cancer tumor definition for high-precision radiotherapy planning. Methods and Materials: Diagnostic quality MRI scans and triphasic CT scans, with the liver immobilized in exhale, were obtained at the time of radiation planning for 26 patients with unresectable liver metastases (n = 8), hepatocellular carcinoma (n = 10), and cholangiocarcinoma (n = 8). On the CT and MRI series best demonstrating the tumor, the liver and gross tumor volumes (GTVs) were contoured, and intrahepatic anatomic reference points were identified. Deformable registration wasmore » used to register the liver from the CT with that from the MRI. Results: A difference in the number of tumor foci was seen on CT vs. MRI in 5 patients with hepatocellular carcinoma: MRI showed more foci in 3 patients, CT in 2. After deformable registration of the livers, the population median of the average distance between the CT tumor surface and MRI tumor surface was 3.7 mm (2.2-21.3 mm). The median percentage of tumor surface area that differed by {>=}5 mm was 26% (1-86%). Median percentage concordance volumes were 81% (77-86%) in metastases, 77% (60-88%) in hepatocellular carcinoma and 64% (25-85%) in cholangiocarcinoma. Conclusion: Differences between MRI-defined liver cancer GTVs and CT-defined GTVs can be substantial and are more common in primary liver cancer.« less

Graph theory analysis of cortical thickness networks in adolescents with d-transposition of the great arteries.

PubMed

Watson, Christopher G; Stopp, Christian; Newburger, Jane W; Rivkin, Michael J

2018-02-01

Adolescents with d-transposition of the great arteries (d-TGA) who had the arterial switch operation in infancy have been found to have structural brain differences compared to healthy controls. We used cortical thickness measurements obtained from structural brain MRI to determine group differences in global brain organization using a graph theoretical approach. Ninety-two d-TGA subjects and 49 controls were scanned using one of two identical 1.5-Tesla MRI systems. Mean cortical thickness was obtained from 34 regions per hemisphere using Freesurfer. A linear model was used for each brain region to adjust for subject age, sex, and scanning location. Structural connectivity for each group was inferred based on the presence of high inter-regional correlations of the linear model residuals, and binary connectivity matrices were created by thresholding over a range of correlation values for each group. Graph theory analysis was performed using packages in R. Permutation tests were performed to determine significance of between-group differences in global network measures. Within-group connectivity patterns were qualitatively different between groups. At lower network densities, controls had significantly more long-range connections. The location and number of hub regions differed between groups: controls had a greater number of hubs at most network densities. The control network had a significant rightward asymmetry compared to the d-TGA group at all network densities. Using graph theory analysis of cortical thickness correlations, we found differences in brain structural network organization among d-TGA adolescents compared to controls. These may be related to the white matter and gray matter differences previously found in this cohort, and in turn may be related to the cognitive deficits this cohort presents.

75 FR 7282 - Circulatory System Devices Panel of the Medical Devices Advisory Committee; Notice of Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-18

... March 19, 2010, the committee will discuss, make recommendations and vote on a PMA for the REVO MRI Pacemaker System sponsored by Medtronic. The REVO MRI Pacing System is a pacemaker (with a standard pacing indication) that has been specifically designed to be safe for the MRI environment under certain MR scanning...

Dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) for the assessment of Pc 4-sensitized photodynamic therapy of a U87-derived glioma model in the athymic nude rat

NASA Astrophysics Data System (ADS)

Anka, Ali; Thompson, Paul; Mott, Eric; Sharma, Rahul; Zhang, Ruozhen; Cross, Nathan; Sun, Jiayang; Flask, Chris A.; Oleinick, Nancy L.; Dean, David

2010-02-01

Introduction: Dynamic Contrast-Enhanced-Magnetic Resonance Imaging (DCE-MRI) may provide a means of tracking the outcome of Pc 4-sensitized photodynamic therapy (PDT) in deeply placed lesions (e.g., brain tumors). We previously determined that 150 μL of gadolinium (Gd-DTPA) produces optimal enhancement of U87-derived intracerebral tumors in an athymic nude rat glioma model. We wish to determine how consistently DCE-MRI enhancement will detect an increase in Gd-enhancement of these tumors following Pc 4-PDT. Methods: We injected 2.5 x 105 U87 cells into the brains of 6 athymic nude rats. After 7-8 days pre-Pc 4 PDT peri-tumor DCE-MRI images were acquired on a 7.0T microMRI scanner before and after administration of 150 μL Gd. DCE-MRI scans were repeated on Days 11, 12, and 13 following Pc 4-PDT (Day 8 or 9). Results: Useful DCE-MRI data were obtained for these animals before and after Pc 4- PDT. In the pre-Pc 4-PDT DCE-MRI scans an average normalized peak Gd enhancement was observed in tumor tissue that was 1.297 times greater than baseline (0.035 Standard Error [SE]). The average normalized peak Gd enhancement in the tumor tissue in the scan following PDT (Day 11) was 1.537 times greater than baseline (0.036 SE), a statistically significant increase in enhancement (p = 0.00584) over the pre-PDT level. Discussion: A 150 μL Gd dose appears to provide an unambiguous increase in signal indicating Pc 4-PDT-induced necrosis of the U87-derived tumor. Our DCEMRI protocol may allow the development of a clinically robust, unambiguous, non-invasive technique for the assessment of PDT outcome.

Significance of clinical examination, CT and MRI scan in the diagnosis of posterior pelvic ring fractures.

PubMed

Nüchtern, J V; Hartel, M J; Henes, F O; Groth, M; Jauch, S Y; Haegele, J; Briem, D; Hoffmann, M; Lehmann, W; Rueger, J M; Großterlinden, L G

2015-02-01

Patients with a fracture in the anterior pelvic ring often simultaneously demonstrate pain in the posterior pelvic ring. The aim of the present prospective study was to assess the sensitivity of CT, MRI and clinical examination in the detection of fractures in the posterior pelvic ring in patients with fractures of the anterior pelvic ring diagnosed in conventional radiographs. Sixty patients with radiographic signs of an anterior pelvic ring injury were included in this prospective analysis. Following a focused clinical examination of the posterior pelvis, all patients underwent both a CT and then a MRI scan of their pelvis. Two board certified radiologists evaluated the CT and MRI scans independently. To estimate the presence of osteoporosis the Hounsfield units of the vertebral body of L5 were measured in each case. Fifty-three women and seven men, with a mean age of 74.7+/-15.6 years were included into the study. A fracture of the posterior pelvic ring was found in fourty-eight patients (80%) patients using MRI. Fractures of the posterior pelvic ring would have been missed in eight cases (17%), if only CT had been used. Eighty-five percent of the patients with a posterior fracture had an osteoporosis. The majority of the cases suffered from a low energy trauma. Thirty-eight patients (83%) with positive clinical signs at the posterior pelvic ring actually had a fracture of the posterior pelvic ring in the MRI. The clinical examination proved to be equally effective to CT in detecting posterior pelvic ring fractures. The significance of both, clinical examination and CT was confirmed in the detection of fractures in the posterior pelvic ring. MRI examination of the pelvis however, was found to be superior in detecting undislocated fractures in a cohort of patients with a high incidence of osteoporosis. Using MRI may be beneficial in select cases, especially when reduced bone density is suspected. Copyright © 2014 Elsevier Ltd. All rights reserved.

Magnetic resonance imaging investigation of the bone conduction implant – a pilot study at 1.5 Tesla

PubMed Central

Jansson, Karl-Johan Fredén; Håkansson, Bo; Reinfeldt, Sabine; Rigato, Cristina; Eeg-Olofsson, Måns

2015-01-01

Purpose The objective of this pilot study was to investigate if an active bone conduction implant (BCI) used in an ongoing clinical study withstands magnetic resonance imaging (MRI) of 1.5 Tesla. In particular, the MRI effects on maximum power output (MPO), total harmonic distortion (THD), and demagnetization were investigated. Implant activation and image artifacts were also evaluated. Methods and materials One implant was placed on the head of a test person at the position corresponding to the normal position of an implanted BCI and applied with a static pressure using a bandage and scanned in a 1.5 Tesla MRI camera. Scanning was performed both with and without the implant, in three orthogonal planes, and for one spin-echo and one gradient-echo pulse sequence. Implant functionality was verified in-between the scans using an audio processor programmed to generate a sequence of tones when attached to the implant. Objective verification was also carried out by measuring MPO and THD on a skull simulator as well as retention force, before and after MRI. Results It was found that the exposure of 1.5 Tesla MRI only had a minor effect on the MPO, ie, it decreased over all frequencies with an average of 1.1±2.1 dB. The THD remained unchanged above 300 Hz and was increased only at lower frequencies. The retention magnet was demagnetized by 5%. The maximum image artifacts reached a distance of 9 and 10 cm from the implant in the coronal plane for the spin-echo and the gradient-echo sequence, respectively. The test person reported no MRI induced sound from the implant. Conclusion This pilot study indicates that the present BCI may withstand 1.5 Tesla MRI with only minor effects on its performance. No MRI induced sound was reported, but the head image was highly distorted near the implant. PMID:26604836

Magnetic resonance imaging investigation of the bone conduction implant - a pilot study at 1.5 Tesla.

PubMed

Jansson, Karl-Johan Fredén; Håkansson, Bo; Reinfeldt, Sabine; Rigato, Cristina; Eeg-Olofsson, Måns

2015-01-01

The objective of this pilot study was to investigate if an active bone conduction implant (BCI) used in an ongoing clinical study withstands magnetic resonance imaging (MRI) of 1.5 Tesla. In particular, the MRI effects on maximum power output (MPO), total harmonic distortion (THD), and demagnetization were investigated. Implant activation and image artifacts were also evaluated. One implant was placed on the head of a test person at the position corresponding to the normal position of an implanted BCI and applied with a static pressure using a bandage and scanned in a 1.5 Tesla MRI camera. Scanning was performed both with and without the implant, in three orthogonal planes, and for one spin-echo and one gradient-echo pulse sequence. Implant functionality was verified in-between the scans using an audio processor programmed to generate a sequence of tones when attached to the implant. Objective verification was also carried out by measuring MPO and THD on a skull simulator as well as retention force, before and after MRI. It was found that the exposure of 1.5 Tesla MRI only had a minor effect on the MPO, ie, it decreased over all frequencies with an average of 1.1±2.1 dB. The THD remained unchanged above 300 Hz and was increased only at lower frequencies. The retention magnet was demagnetized by 5%. The maximum image artifacts reached a distance of 9 and 10 cm from the implant in the coronal plane for the spin-echo and the gradient-echo sequence, respectively. The test person reported no MRI induced sound from the implant. This pilot study indicates that the present BCI may withstand 1.5 Tesla MRI with only minor effects on its performance. No MRI induced sound was reported, but the head image was highly distorted near the implant.

METastasis Reporting and Data System for Prostate Cancer: Practical Guidelines for Acquisition, Interpretation, and Reporting of Whole-body Magnetic Resonance Imaging-based Evaluations of Multiorgan Involvement in Advanced Prostate Cancer.

PubMed

Padhani, Anwar R; Lecouvet, Frederic E; Tunariu, Nina; Koh, Dow-Mu; De Keyzer, Frederik; Collins, David J; Sala, Evis; Schlemmer, Heinz Peter; Petralia, Giuseppe; Vargas, H Alberto; Fanti, Stefano; Tombal, H Bertrand; de Bono, Johann

2017-01-01

Comparative reviews of whole-body magnetic resonance imaging (WB-MRI) and positron emission tomography/computed tomography (CT; with different radiotracers) have shown that metastasis detection in advanced cancers is more accurate than with currently used CT and bone scans. However, the ability of WB-MRI and positron emission tomography/CT to assess therapeutic benefits has not been comprehensively evaluated. There is also considerable variability in the availability and quality of WB-MRI, which is an impediment to clinical development. Expert recommendations for standardising WB-MRI scans are needed, in order to assess its performance in advanced prostate cancer (APC) clinical trials. To design recommendations that promote standardisation and diminish variations in the acquisition, interpretation, and reporting of WB-MRI scans for use in APC. An international expert panel of oncologic imagers and oncologists with clinical and research interests in APC management assessed biomarker requirements for clinical care and clinical trials. Key requirements for a workable WB-MRI protocol, achievable quality standards, and interpretation criteria were identified and synthesised in a white paper. The METastasis Reporting and Data System for Prostate Cancer guidelines were formulated for use in all oncologic manifestations of APC. Uniformity in imaging data acquisition, quality, and interpretation of WB-MRI are essential for assessing the test performance of WB-MRI. The METastasis Reporting and Data System for Prostate Cancer standard requires validation in clinical trials of treatment approaches in APC. METastasis Reporting and Data System for Prostate Cancer represents the consensus recommendations on the performance, quality standards, and reporting of whole-body magnetic resonance imaging, for use in all oncologic manifestations of advanced prostate cancer. These new criteria require validation in clinical trials of established and new treatment approaches in advanced prostate cancer. Copyright © 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Multisite Reliability of MR-Based Functional Connectivity

PubMed Central

Noble, Stephanie; Scheinost, Dustin; Finn, Emily S.; Shen, Xilin; Papademetris, Xenophon; McEwen, Sarah C.; Bearden, Carrie E.; Addington, Jean; Goodyear, Bradley; Cadenhead, Kristin S.; Mirzakhanian, Heline; Cornblatt, Barbara A.; Olvet, Doreen M.; Mathalon, Daniel H.; McGlashan, Thomas H.; Perkins, Diana O.; Belger, Aysenil; Seidman, Larry J.; Thermenos, Heidi; Tsuang, Ming T.; van Erp, Theo G.M.; Walker, Elaine F.; Hamann, Stephan; Woods, Scott W.; Cannon, Tyrone D.; Constable, R. Todd

2016-01-01

Recent years have witnessed an increasing number of multisite MRI functional connectivity (fcMRI) studies. While multisite studies are an efficient way to speed up data collection and increase sample sizes, especially for rare clinical populations, any effects of site or MRI scanner could ultimately limit power and weaken results. Little data exists on the stability of functional connectivity measurements across sites and sessions. In this study, we assess the influence of site and session on resting state functional connectivity measurements in a healthy cohort of traveling subjects (8 subjects scanned twice at each of 8 sites) scanned as part of the North American Prodrome Longitudinal Study (NAPLS). Reliability was investigated in three types of connectivity analyses: (1) seed-based connectivity with posterior cingulate cortex (PCC), right motor cortex (RMC), and left thalamus (LT) as seeds; (2) the intrinsic connectivity distribution (ICD), a voxel-wise connectivity measure; and (3) matrix connectivity, a whole-brain, atlas-based approach assessing connectivity between nodes. Contributions to variability in connectivity due to subject, site, and day-of-scan were quantified and used to assess between-session (test-retest) reliability in accordance with Generalizability Theory. Overall, no major site, scanner manufacturer, or day-of-scan effects were found for the univariate connectivity analyses; instead, subject effects dominated relative to the other measured factors. However, summaries of voxel-wise connectivity were found to be sensitive to site and scanner manufacturer effects. For all connectivity measures, although subject variance was three times the site variance, the residual represented 60–80% of the variance, indicating that connectivity differed greatly from scan to scan independent of any of the measured factors (i.e., subject, site, and day-of-scan). Thus, for a single 5 min scan, reliability across connectivity measures was poor (ICC=0.07–0.17), but increases with increasing scan duration (ICC=0.21–0.36 at 25 min). The limited effects of site and scanner manufacturer support the use of multisite studies, such as NAPLS, as a viable means of collecting data on rare populations and increasing power in univariate functional connectivity studies. However, the results indicate that aggregation of fcMRI data across longer scan durations is necessary to increase the reliability of connectivity estimates at the single-subject level. PMID:27746386

Spatial Distortion in MRI-Guided Stereotactic Procedures: Evaluation in 1.5-, 3- and 7-Tesla MRI Scanners.

PubMed

Neumann, Jan-Oliver; Giese, Henrik; Biller, Armin; Nagel, Armin M; Kiening, Karl

2015-01-01

Magnetic resonance imaging (MRI) is replacing computed tomography (CT) as the main imaging modality for stereotactic transformations. MRI is prone to spatial distortion artifacts, which can lead to inaccuracy in stereotactic procedures. Modern MRI systems provide distortion correction algorithms that may ameliorate this problem. This study investigates the different options of distortion correction using standard 1.5-, 3- and 7-tesla MRI scanners. A phantom was mounted on a stereotactic frame. One CT scan and three MRI scans were performed. At all three field strengths, two 3-dimensional sequences, volumetric interpolated breath-hold examination (VIBE) and magnetization-prepared rapid acquisition with gradient echo, were acquired, and automatic distortion correction was performed. Global stereotactic transformation of all 13 datasets was performed and two stereotactic planning workflows (MRI only vs. CT/MR image fusion) were subsequently analysed. Distortion correction on the 1.5- and 3-tesla scanners caused a considerable reduction in positional error. The effect was more pronounced when using the VIBE sequences. By using co-registration (CT/MR image fusion), even a lower positional error could be obtained. In ultra-high-field (7 T) MR imaging, distortion correction introduced even higher errors. However, the accuracy of non-corrected 7-tesla sequences was comparable to CT/MR image fusion 3-tesla imaging. MRI distortion correction algorithms can reduce positional errors by up to 60%. For stereotactic applications of utmost precision, we recommend a co-registration to an additional CT dataset. © 2015 S. Karger AG, Basel.

3D documentation and visualization of external injury findings by integration of simple photography in CT/MRI data sets (IprojeCT).

PubMed

Campana, Lorenzo; Breitbeck, Robert; Bauer-Kreuz, Regula; Buck, Ursula

2016-05-01

This study evaluated the feasibility of documenting patterned injury using three dimensions and true colour photography without complex 3D surface documentation methods. This method is based on a generated 3D surface model using radiologic slice images (CT) while the colour information is derived from photographs taken with commercially available cameras. The external patterned injuries were documented in 16 cases using digital photography as well as highly precise photogrammetry-supported 3D structured light scanning. The internal findings of these deceased were recorded using CT and MRI. For registration of the internal with the external data, two different types of radiographic markers were used and compared. The 3D surface model generated from CT slice images was linked with the photographs, and thereby digital true-colour 3D models of the patterned injuries could be created (Image projection onto CT/IprojeCT). In addition, these external models were merged with the models of the somatic interior. We demonstrated that 3D documentation and visualization of external injury findings by integration of digital photography in CT/MRI data sets is suitable for the 3D documentation of individual patterned injuries to a body. Nevertheless, this documentation method is not a substitution for photogrammetry and surface scanning, especially when the entire bodily surface is to be recorded in three dimensions including all external findings, and when precise data is required for comparing highly detailed injury features with the injury-inflicting tool.

"Hidden" bone metastasis from thyroid carcinoma: a clinical note.

PubMed

Sioka, C; Skarulis, M C; Tulloch-Reid, M K; Heiss, J D; Reynolds, J C

2014-01-01

The (131)I-iodide ((131)I) whole-body scan, for thyroid carcinoma is at times difficult to interpret. In a diagnostic whole body (131)I scan of a patient with follicular carcinoma, a posterior skull lesion was partially hidden by overlapping facial structures. On lateral head view, the abnormality was clearly evident. SPECT/CT and MRI showed the lesion originated in the occipital bone and had enlarged into the posterior fossa. The mass was surgically removed and the patient received (131)I therapy for residual tissue. The study demonstrates a pitfall in the reading of two dimensional radioiodine images which can be overcome by SPECT or lateral imaging. Copyright © 2013 Elsevier España, S.L. and SEMNIM. All rights reserved.

83. Ventricular Enlargement and Progressive Reduction in Cortical Gray Matter Are Linked in Prodromal Youth Who Develop Psychosis

PubMed Central

Chung, Yoonho; Haut, Kristen; He, George; Van Erp, Theo; McEwen, Sarah; Addington, Jean; Bearden, Carrie; Cadenhead, Kristin; Cornblatt, Barbara; Mathalon, Daniel; McGlashan, Thomas; Perkins, Diana; Seidman, Larry; Tsuang, Ming; Walker, Elaine; Woods, Scott; Cannon, Tyrone

2017-01-01

Abstract Background: In a recent prospective longitudinal neuroimaging study, clinical high-risk (CHR) individuals who later developed full-blown psychosis showed an accelerated rate of gray matter thinning in superior and medial prefrontal cortex (PFC) and expansion of the ventricular system after applying a stringent correction for multiple comparisons. Although cortical and subcortical volume loss and enlarged ventricles are well characterized structural brain abnormalities among patients with schizophrenia, no prior study has evaluated whether these progressive changes of neuroanatomical indicators are linked in time prior to onset of psychosis. Therefore, we investigated the relationship between the changes in cortical gray matter thickness and ventricular volume using the longitudinal neuroimaging data from the North American Prodrome Longitudinal Study (NAPLS) at the whole-brain level. Methods: MRI structural data were acquired at baseline and 12-month follow-up, and follow-up scans for those who developed fully psychotic symptoms were assessed at the point of conversion. In total, 37 CHR cases who converted to psychosis, 230 CHR cases who did not convert (nonconverters), and 132 healthy comparison subjects had usable baseline and second time point scans. Imaging measures were first transformed to annualized rates of percent change (ARCH) in each cortical vertex. Interval is the time between BL and FU scans in years. Relationships between ARCH of total ventricle volume and ARCH of cortical gray matter values were tested vertex-wise using the general linear model. Among the subjects with BL and 12-FU data available, 125 CHR cases and 66 controls were followed to an additional third time point for a 24-month MRI assessment. For the purpose of testing the replicability of our main hypotheses, neuroanatomical ARCH measures between the 12 and 24 month follow-ups were also computed with a parallel set of statistical tests as described earlier. Results: The results showed that ventricular expansion is linked in time to progressive reduction of gray matter, rather than to structural changes in proximal subcortical regions, in a broadly distributed set of cortical regions among CHR youth, including superior, medial, lateral, and inferior PFC, superior temporal gyrus, and parietal cortices. In contrast, the healthy controls did not show the same pattern of associations. The main findings were further replicated using a third assessment wave of MRI scans in a subset of study participants who were followed for an additional year. Conclusion: In summary, expansion of the ventricular spaces is linked in time with an accelerated rate of widespread cortical thinning prior to psychosis onset. The cortical regions experiencing altered maturation during the psychosis prodrome may be more widespread than the regionally specific clusters that have been identified in previous case–control studies

Abdominal ultrasound (image)

MedlinePlus

Abdominal ultrasound is a scanning technique used to image the interior of the abdomen. Like the X-ray, MRI, ... it has its place as a diagnostic tool. Ultrasound scans use high frequency sound waves to produce ...

Bayesian automated cortical segmentation for neonatal MRI

NASA Astrophysics Data System (ADS)

Chou, Zane; Paquette, Natacha; Ganesh, Bhavana; Wang, Yalin; Ceschin, Rafael; Nelson, Marvin D.; Macyszyn, Luke; Gaonkar, Bilwaj; Panigrahy, Ashok; Lepore, Natasha

2017-11-01

Several attempts have been made in the past few years to develop and implement an automated segmentation of neonatal brain structural MRI. However, accurate automated MRI segmentation remains challenging in this population because of the low signal-to-noise ratio, large partial volume effects and inter-individual anatomical variability of the neonatal brain. In this paper, we propose a learning method for segmenting the whole brain cortical grey matter on neonatal T2-weighted images. We trained our algorithm using a neonatal dataset composed of 3 fullterm and 4 preterm infants scanned at term equivalent age. Our segmentation pipeline combines the FAST algorithm from the FSL library software and a Bayesian segmentation approach to create a threshold matrix that minimizes the error of mislabeling brain tissue types. Our method shows promising results with our pilot training set. In both preterm and full-term neonates, automated Bayesian segmentation generates a smoother and more consistent parcellation compared to FAST, while successfully removing the subcortical structure and cleaning the edges of the cortical grey matter. This method show promising refinement of the FAST segmentation by considerably reducing manual input and editing required from the user, and further improving reliability and processing time of neonatal MR images. Further improvement will include a larger dataset of training images acquired from different manufacturers.

Striatal changes in Parkinson disease: An investigation of morphology, functional connectivity and their relationship to clinical symptoms.

PubMed

Owens-Walton, Conor; Jakabek, David; Li, Xiaozhen; Wilkes, Fiona A; Walterfang, Mark; Velakoulis, Dennis; van Westen, Danielle; Looi, Jeffrey C L; Hansson, Oskar

2018-05-30

We sought to investigate morphological and resting state functional connectivity changes to the striatal nuclei in Parkinson disease (PD) and examine whether changes were associated with measures of clinical function. Striatal nuclei were manually segmented on 3T-T1 weighted MRI scans of 74 PD participants and 27 control subjects, quantitatively analysed for volume, shape and also functional connectivity using functional MRI data. Bilateral caudate nuclei and putamen volumes were significantly reduced in the PD cohort compared to controls. When looking at left and right hemispheres, the PD cohort had significantly smaller left caudate nucleus and right putamen volumes compared to controls. A significant correlation was found between greater atrophy of the caudate nucleus and poorer cognitive function, and between greater atrophy of the putamen and more severe motor symptoms. Resting-state functional MRI analysis revealed altered functional connectivity of the striatal structures in the PD group. This research demonstrates that PD involves atrophic changes to the caudate nucleus and putamen that are linked to clinical dysfunction. Our work reveals important information about a key structure-function relationship in the brain and provides support for caudate nucleus and putamen atrophy as neuroimaging biomeasures in PD. Copyright © 2018 Elsevier B.V. All rights reserved.

A systematic review of the need for MRI for the clearance of cervical spine injury in obtunded blunt trauma patients after normal cervical spine CT.

PubMed

James, Iyore Ao; Moukalled, Ahmad; Yu, Elizabeth; Tulman, David B; Bergese, Sergio D; Jones, Christian D; Stawicki, Stanislaw Pa; Evans, David C

2014-10-01

Clearance of cervical spine injury (CSI) in the obtunded or comatose blunt trauma patient remains controversial. In patients with unreliable physical examination and no evidence of CSI on computed tomography (CT), magnetic resonance imaging of the cervical spine (CS-MRI) is the typical follow-up study. There is a growing body of evidence suggesting that CS-MRI is unnecessary with negative findings on a multi-detector CT (MDCT) scan. This review article systematically analyzes current literature to address the controversies surrounding clearance of CSI in obtunded blunt trauma patients. A literature search through MEDLINE database was conducted using all databases on the National Center for Biotechnology Information (NCBI) website (www.ncbi.nlm.nih.gov) for keywords: "cervical spine injury," "obtunded," and "MRI." The search was limited to studies published within the last 10 years and with populations of patients older than 18 years old. Eleven studies were included in the analysis yielding data on 1535 patients. CS-MRI detected abnormalities in 256 patients (16.6%). The abnormalities reported on CS-MRI resulted in prolonged rigid c-collar immobilization in 74 patients (4.9%). Eleven patients (0.7%) had unstable injury detected on CS-MRI alone that required surgical intervention. In the obtunded blunt trauma patient with unreliable clinical examination and a normal CT scan, there is still a role for CS-MRI in detecting clinically significant injuries when MRI resources are available. However, when a reliable clinical exam reveals intact gross motor function, CS-MRI may be unnecessary.

An anthropomorphic phantom for quantitative evaluation of breast MRI.

PubMed

Freed, Melanie; de Zwart, Jacco A; Loud, Jennifer T; El Khouli, Riham H; Myers, Kyle J; Greene, Mark H; Duyn, Jeff H; Badano, Aldo

2011-02-01

In this study, the authors aim to develop a physical, tissue-mimicking phantom for quantitative evaluation of breast MRI protocols. The objective of this phantom is to address the need for improved standardization in breast MRI and provide a platform for evaluating the influence of image protocol parameters on lesion detection and discrimination. Quantitative comparisons between patient and phantom image properties are presented. The phantom is constructed using a mixture of lard and egg whites, resulting in a random structure with separate adipose- and glandular-mimicking components. T1 and T2 relaxation times of the lard and egg components of the phantom were estimated at 1.5 T from inversion recovery and spin-echo scans, respectively, using maximum-likelihood methods. The image structure was examined quantitatively by calculating and comparing spatial covariance matrices of phantom and patient images. A static, enhancing lesion was introduced by creating a hollow mold with stereolithography and filling it with a gadolinium-doped water solution. Measured phantom relaxation values fall within 2 standard errors of human values from the literature and are reasonably stable over 9 months of testing. Comparison of the covariance matrices of phantom and patient data demonstrates that the phantom and patient data have similar image structure. Their covariance matrices are the same to within error bars in the anterior-posterior direction and to within about two error bars in the right-left direction. The signal from the phantom's adipose-mimicking material can be suppressed using active fat-suppression protocols. A static, enhancing lesion can also be included with the ability to change morphology and contrast agent concentration. The authors have constructed a phantom and demonstrated its ability to mimic human breast images in terms of key physical properties that are relevant to breast MRI. This phantom provides a platform for the optimization and standardization of breast MRI imaging protocols for lesion detection and characterization.

Improved operator agreement and efficiency using the minimum area contour change method for delineation of hyperintense multiple sclerosis lesions on FLAIR MRI

PubMed Central

2013-01-01

Background Activity of disease in patients with multiple sclerosis (MS) is monitored by detecting and delineating hyper-intense lesions on MRI scans. The Minimum Area Contour Change (MACC) algorithm has been created with two main goals: a) to improve inter-operator agreement on outlining regions of interest (ROIs) and b) to automatically propagate longitudinal ROIs from the baseline scan to a follow-up scan. Methods The MACC algorithm first identifies an outer bound for the solution path, forms a high number of iso-contour curves based on equally spaced contour values, and then selects the best contour value to outline the lesion. The MACC software was tested on a set of 17 FLAIR MRI images evaluated by a pair of human experts and a longitudinal dataset of 12 pairs of T2-weighted Fluid Attenuated Inversion Recovery (FLAIR) images that had lesion analysis ROIs drawn by a single expert operator. Results In the tests where two human experts evaluated the same MRI images, the MACC program demonstrated that it could markedly reduce inter-operator outline error. In the longitudinal part of the study, the MACC program created ROIs on follow-up scans that were in close agreement to the original expert’s ROIs. Finally, in a post-hoc analysis of 424 follow-up scans 91% of propagated MACC were accepted by an expert and only 9% of the final accepted ROIS had to be created or edited by the expert. Conclusion When used with an expert operator's verification of automatically created ROIs, MACC can be used to improve inter- operator agreement and decrease analysis time, which should improve data collected and analyzed in multicenter clinical trials. PMID:24004511

The value of multimodality imaging in the investigation of a PSA recurrence after radical prostatectomy in the Irish hospital setting.

PubMed

McLoughlin, L C; Inder, S; Moran, D; O'Rourke, C; Manecksha, R P; Lynch, T H

2018-02-01

The diagnostic evaluation of a PSA recurrence after RP in the Irish hospital setting involves multimodality imaging with MRI, CT, and bone scanning, despite the low diagnostic yield from imaging at low PSA levels. We aim to investigate the value of multimodality imaging in PC patients after RP with a PSA recurrence. Forty-eight patients with a PSA recurrence after RP who underwent multimodality imaging were evaluated. Demographic data, postoperative PSA levels, and imaging studies performed at those levels were evaluated. Eight (21%) MRIs, 6 (33%) CTs, and 4 (9%) bone scans had PCa-specific findings. Three (12%) patients had a positive MRI with a PSA <1.0 ng/ml, while 5 (56%) were positive at PSA ≥1.1 ng/ml (p = 0.05). Zero patient had a positive CT TAP at a PSA level <1.0 ng/ml, while 5 (56%) were positive at levels ≥1.1 ng/ml (p = 0.03). Zero patient had a positive bone at PSA levels <1.0 ng/ml, while 4 (27%) were positive at levels ≥1.1 ng/ml (p = 0.01). The diagnostic yield from multimodality imaging, and isotope bone scanning in particular, in PSA levels <1.0 ng/ml, is low. There is a statistically significant increase in the frequency of positive findings on CT and bone scanning at PSA levels ≥1.1 ng/ml. MRI alone is of investigative value at PSA <1.0 ng/ml. The indication for CT, MRI, or isotope bone scanning should be carefully correlated with the clinical question and how it will affect further management.

Onset of multiple sclerosis before adulthood leads to failure of age-expected brain growth

PubMed Central

Aubert-Broche, Bérengère; Fonov, Vladimir; Narayanan, Sridar; Arnold, Douglas L.; Araujo, David; Fetco, Dumitru; Till, Christine; Sled, John G.; Collins, D. Louis

2014-01-01

Objective: To determine the impact of pediatric-onset multiple sclerosis (MS) on age-expected brain growth. Methods: Whole brain and regional volumes of 36 patients with relapsing-remitting MS onset prior to 18 years of age were segmented in 185 longitudinal MRI scans (2–11 scans per participant, 3-month to 2-year scan intervals). MRI scans of 25 age- and sex-matched healthy normal controls (NC) were also acquired at baseline and 2 years later on the same scanner as the MS group. A total of 874 scans from 339 participants from the NIH-funded MRI study of normal brain development acquired at 2-year intervals were used as an age-expected healthy growth reference. All data were analyzed with an automatic image processing pipeline to estimate the volume of brain and brain substructures. Mixed-effect models were built using age, sex, and group as fixed effects. Results: Significant group and age interactions were found with the adjusted models fitting brain volumes and normalized thalamus volumes (p < 10−4). These findings indicate a failure of age-normative brain growth for the MS group, and an even greater failure of thalamic growth. In patients with MS, T2 lesion volume correlated with a greater reduction in age-expected thalamic volume. To exclude any scanner-related influence on our data, we confirmed no significant interaction of group in the adjusted models between the NC and NIH MRI Study of Normal Brain Development groups. Conclusions: Our results provide evidence that the onset of MS during childhood and adolescence limits age-expected primary brain growth and leads to subsequent brain atrophy, implicating an early onset of the neurodegenerative aspect of MS. PMID:25378667

Primate Brain Anatomy: New Volumetric MRI Measurements for Neuroanatomical Studies.

PubMed

Navarrete, Ana F; Blezer, Erwin L A; Pagnotta, Murillo; de Viet, Elizabeth S M; Todorov, Orlin S; Lindenfors, Patrik; Laland, Kevin N; Reader, Simon M

2018-06-12

Since the publication of the primate brain volumetric dataset of Stephan and colleagues in the early 1980s, no major new comparative datasets covering multiple brain regions and a large number of primate species have become available. However, technological and other advances in the last two decades, particularly magnetic resonance imaging (MRI) and the creation of institutions devoted to the collection and preservation of rare brain specimens, provide opportunities to rectify this situation. Here, we present a new dataset including brain region volumetric measurements of 39 species, including 20 species not previously available in the literature, with measurements of 16 brain areas. These volumes were extracted from MRI of 46 brains of 38 species from the Netherlands Institute of Neuroscience Primate Brain Bank, scanned at high resolution with a 9.4-T scanner, plus a further 7 donated MRI of 4 primate species. Partial measurements were made on an additional 8 brains of 5 species. We make the dataset and MRI scans available online in the hope that they will be of value to researchers conducting comparative studies of primate evolution. © 2018 S. Karger AG, Basel.

Focused tight dressing does not prevent cochlear implant magnet migration under 1.5 Tesla MRI.

PubMed

Cuda, D; Murri, A; Succo, G

2013-04-01

We report a retrospective case of inner magnet migration, which occurred after 1.5 Tesla MRI scanning in an adult recipient of a bilateral cochlear implant (CI) despite a focused head dressing. The patient, bilaterally implanted with Nucleus 5 CIs (Cochlear LTD, Sydney, Australia), underwent a 1.5 Tesla cholangio-MRI scan for biliary duct pathology. In subsequent days, a focal skin alteration appeared over the left inner coil. Plain skull radiographs showed partial magnet migration on the left side. Surgical exploration confirmed magnet twisting; the magnet was effectively repositioned. Left CI performance was restored to pre-migration level. The wound healed without complications. Thus, focused dressing does not prevent magnet migration in CI recipients undergoing 1.5 Tesla MRI. All patients should be counselled on this potential complication. A minor surgical procedure is required to reposition the magnet. Nevertheless, timely diagnosis is necessary to prevent skin breakdown and subsequent device contamination. Plain skull radiograph is very effective in identifying magnet twisting; it should be performed systematically after MRI or minimally on all suspected cases.

Canine hippocampal formation composited into three-dimensional structure using MPRAGE.

PubMed

Jung, Mi-Ae; Nahm, Sang-Soep; Lee, Min-Su; Lee, In-Hye; Lee, Ah-Ra; Jang, Dong-Pyo; Kim, Young-Bo; Cho, Zang-Hee; Eom, Ki-Dong

2010-07-01

This study was performed to anatomically illustrate the living canine hippocampal formation in three-dimensions (3D), and to evaluate its relationship to surrounding brain structures. Three normal beagle dogs were scanned on a MR scanner with inversion recovery segmented 3D gradient echo sequence (known as MP-RAGE: Magnetization Prepared Rapid Gradient Echo). The MRI data was manually segmented and reconstructed into a 3D model using the 3D slicer software tool. From the 3D model, the spatial relationships between hippocampal formation and surrounding structures were evaluated. With the increased spatial resolution and contrast of the MPRAGE, the canine hippocampal formation was easily depicted. The reconstructed 3D image allows easy understanding of the hippocampal contour and demonstrates the structural relationship of the hippocampal formation to surrounding structures in vivo.

Non-Hodgkin Lymphoma (For Parents)

MedlinePlus

... chest X-ray a computerized tomography (CT or CAT) scan , which rotates around the patient and creates an ... ray (Video) Getting an MRI (Video) Getting a CAT Scan (Video) Chemotherapy Hodgkin Lymphoma Stem Cell Transplants Can ...

75 FR 50767 - Government-Owned Inventions; Availability for Licensing

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-17

... MRI and CT scans; however, these scans cannot detect tumor type, i.e. glioblastoma vs. medulloblastoma...: Global cancer market is worth more than eight percent of total global pharmaceutical sales. Cancer...

Structure Measurements of Leaf and Woody Components of Forests with Dual-Wavelength Lidar Scanning Data

NASA Astrophysics Data System (ADS)

Strahler, A. H.; Li, Z.; Schaaf, C.; Howe, G.; Martel, J.; Hewawasam, K.; Douglas, E. S.; Chakrabarti, S.; Cook, T.; Paynter, I.; Saenz, E. J.; Wang, Z.; Woodcock, C. E.; Jupp, D. L. B.; Schaefer, M.; Newnham, G.

2014-12-01

Forest structure plays a critical role in the exchange of energy, carbon and water between land and atmosphere and nutrient cycle. We can provide detailed forest structure measurements of leaf and woody components with the Dual Wavelength Echidna® Lidar (DWEL), which acquires full-waveform scans at both near-infrared (NIR, 1064 nm) and shortwave infrared (SWIR, 1548 nm) wavelengths from simultaneous laser pulses. We collected DWEL scans at a broadleaf forest stand and a conifer forest stand at Harvard Forest in June 2014. Power returned from leaves is much lower than from woody materials such as trunks and branches at the SWIR wavelength due to the liquid water absorption by leaves, whereas returned power at the NIR wavelength is similar from both leaves and woody materials. We threshold a normalized difference index (NDI), defined as the difference between returned power at the two wavelengths divided by their sum, to classify each return pulse as a leaf or trunk/branch hit. We obtain leaf area index (LAI), woody area index (WAI) and vertical profiles of leaf and woody components directly from classified lidar hits without empirical wood-to-total ratios as are commonly used in optical methods of LAI estimation. Tree heights, diameter at breast height (DBH), and stem count density are the other forest structure parameters estimated from our DWEL scans. The separation of leaf and woody components in tandem with fine-scale forest structure measurements will benefit studies on carbon allocation of forest ecosystems and improve our understanding of the effects of forest structure on ecosystem functions. This research is supported by NSF grant, MRI-0923389

Retrospective imaging study on the diagnosis of pathological false positive iodine-131 scans in patients with thyroid cancer.

PubMed

Jia, Qiang; Meng, Zhaowei; Tan, Jian; Zhang, Guizhi; He, Yajing; Sun, Haoran; Yu, Chunshui; Li, Dong; Zheng, Wei; Wang, Renfei; Wang, Shen; Li, Xue; Zhang, Jianping; Hu, Tianpeng; Liu, N A; Upadhyaya, Arun

2015-11-01

Iodine-131 (I-131) therapy and post-therapy I-131 scanning are essential in the management of differentiated thyroid cancer (DTC). However, pathological false positive I-131 scans can lead to misdiagnosis and inappropriate I-131 treatment. This retrospective study aimed to investigate the best imaging modality for the diagnosis of pathological false positive I-131 scans in a DTC patient cohort, and to determine its incidence. DTC patient data archived from January 2008 to January 2010 was retrieved. Post-therapeutic I-131 scans were conducted and interpreted. The imaging modalities of magnetic resonance imaging (MRI), computed tomography and ultrasonography were applied and compared to check all suspected lesions. Biopsy or needle aspiration was conducted for patients who consented to the acquisition of histopathological confirmation. Data for 156 DTC patients were retrieved. Only 6 cases of pathological false-positives were found among these (incidence, 3.85%), which included 3 cases of thymic hyperplasia in the mediastinum, 1 case of pleomorphic adenoma in the parapharyngeal space and 1 case of thyroglossal duct cyst in the neck. MRI was demonstrated as the best imaging modality for diagnosis due to its superior soft tissue resolution. However, no imaging modality was able to identify the abdominal false positive-lesions observed in 2 cases, one of whom also had thymic hyperplasia. In conclusion, pathological false positive I-131 scans occurred with an incidence of 3.85%. MRI was the best imaging modality for diagnosing these pathological false-positives.

Reliable identification of deep sulcal pits: the effects of scan session, scanner, and surface extraction tool.

PubMed

Im, Kiho; Lee, Jong-Min; Jeon, Seun; Kim, Jong-Heon; Seo, Sang Won; Na, Duk L; Grant, P Ellen

2013-01-01

Sulcal pit analysis has been providing novel insights into brain function and development. The purpose of this study was to evaluate the reliability of sulcal pit extraction with respect to the effects of scan session, scanner, and surface extraction tool. Five subjects were scanned 4 times at 3 MRI centers and other 5 subjects were scanned 3 times at 2 MRI centers, including 1 test-retest session. Sulcal pits were extracted on the white matter surfaces reconstructed with both Montreal Neurological Institute and Freesurfer pipelines. We estimated similarity of the presence of sulcal pits having a maximum value of 1 and their spatial difference within the same subject. The tests showed high similarity of the sulcal pit presence and low spatial difference. The similarity was more than 0.90 and the spatial difference was less than 1.7 mm in most cases according to different scan sessions or scanners, and more than 0.85 and about 2.0 mm across surface extraction tools. The reliability of sulcal pit extraction was more affected by the image processing-related factors than the scan session or scanner factors. Moreover, the similarity of sulcal pit distribution appeared to be largely influenced by the presence or absence of the sulcal pits on the shallow and small folds. We suggest that our sulcal pit extraction from MRI is highly reliable and could be useful for clinical applications as an imaging biomarker.

Application of the McDonald MRI criteria in multiple sclerosis.

PubMed

Chan, Ling Ling; Sitoh, Yih Yian; Chong, June; See, Siew Ju; Umapathi, Thirugnanam N; Lim, Shih Hui; Ong, Benjamin

2007-08-01

The aim of this study was to assess the sensitivity of McDonald's magnetic resonance imaging (MRI) criteria for the diagnosis of multiple sclerosis (MS) in a group of Asian patients diagnosed with clinically definite MS, based on lesion characterisation on MRI scans. Forty-nine patients from 3 major neurological institutions were classified as having Asian- or Western-type MS based on clinical assessment. Each MRI scan was reviewed by 2 neuroradiologists for the presence and characteristics of brain and spinal lesions. The McDonald's MRI criteria were then applied and its sensitivity evaluated. Nine patients were excluded, leaving 34 females and 6 males who were dominantly Chinese (90%), with a mean age of 36.2 years. The MRI brain and spinal findings were detailed and tabulated. Statistically significant differences (P <0.01) in MRI brain findings and sensitivity of McDonald's MRI criteria were found between our Asian- and Western-type MS patients. The diagnostic yield of McDonald's MRI criteria increased by 20% when we substituted a cord for a brain lesion, and applied the substitution for enhancing cord lesions as well. The diagnosis is more likely to be made when using McDonald MRI criteria based on brain findings, in a patient who presents clinically with Western-type MS. The provision for substitution of "one brain for a spinal lesion" is helpful in Asian-type MS, where there is preponderance of spinal lesion load. Our findings suggest that minor modifications in the interpretation of McDonald's MRI criteria have significant impact on the diagnosis in patients clinically presenting as Asian-type MS, with potential bearing on their subsequent management.

Accuracy of magnetic resonance imaging to detect cartilage loss in severe osteoarthritis of the first carpometacarpal joint: comparison with histological evaluation.

PubMed

Saltzherr, Michael S; Coert, J Henk; Selles, Ruud W; van Neck, Johan W; Jaquet, Jean-Bart; van Osch, Gerjo J V M; Oei, Edwin H G; Luime, Jolanda J; Muradin, Galied S R

2017-03-14

Magnetic resonance imaging (MRI) is increasingly used for research in hand osteoarthritis, but imaging the thin cartilage layers in the hand joints remains challenging. We therefore assessed the accuracy of MRI in detecting cartilage loss in patients with symptomatic osteoarthritis of the first carpometacarpal (CMC1) joint. Twelve patients scheduled for trapeziectomy to treat severe symptomatic osteoarthritis of the CMC1 joint underwent a preoperative high resolution 3D spoiled gradient (SPGR) MRI scan. Subsequently, the resected trapezium was evaluated histologically. The sections were scored for cartilage damage severity (Osteoarthritis Research Society International (OARSI) score), and extent of damage (percentage surface area). Each MRI scan was scored for the area of normal cartilage, partial cartilage loss and full cartilage loss. The percentages of the total surface area with any cartilage loss and full-thickness cartilage loss were calculated using MRI and histological evaluation. MRI and histological evaluation both identified large areas of overall cartilage loss. The median (IQR) surface area of any cartilage loss on MRI was 98% (82-100%), and on histological assessment 96% (87-98%). However, MRI underestimated the extent of full-thickness cartilage loss. The median (IQR) surface area of full-thickness cartilage loss on MRI was 43% (22-70%), and on histological evaluation 79% (67-85%). The difference was caused by a thin layer of high signal on the articulating surface, which was interpreted as damaged cartilage on MRI but which was not identified on histological evaluation. Three-dimensional SPGR MRI of the CMC1 joint demonstrates overall cartilage damage, but underestimates full-thickness cartilage loss in patients with advanced osteoarthritis.

Applicability of McDonald 2010 and Magnetic Resonance Imaging in Multiple Sclerosis (MAGNIMS) 2016 Magnetic Resonance Imaging Criteria for the Diagnosis of Multiple Sclerosis in Sri Lanka.

PubMed

Gamage, Sujani Madhurika Kodagoda; Wijeweera, Indunil; Wijesinghe, Priyangi; Adikari, Sanjaya Bandara; Fink, Katharina; Sominanda, Herath Mudiyanselage Ajith

2018-05-31

The magnetic resonance imaging in multiple sclerosis (MAGNIMS) group recently proposed guidelines to replace the existing dissemination-in-space criteria in McDonald 2010 magnetic resonance imaging (MRI) criteria for diagnosing multiple sclerosis. There has been insufficient research regarding their applicability in Asians. Objective of this study was to determine the sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of McDonald 2010 and MAGNIMS 2016 MRI criteria with the aim of verifying their applicability in Sri Lankan patients. Patients with clinically isolated syndrome diagnosed by consultant neurologists were recruited from five major neurology centers. Baseline and follow-up MRI scans were performed within 3 months from the initial presentation and at one year after baseline MRI, respectively. McDonald 2010 and MAGNIMS 2016 MRI criteria were applied to all MRI scans. Patients were followed-up for 2 years to assess the conversion to clinically definite multiple sclerosis (CDMS). The sensitivity, specificity, accuracy, PPV, and NPV for predicting the conversion to CDMS were calculated. Forty-two of 66 patients converted to CDMS. Thirty-seven fulfilled the McDonald 2010 MRI criteria, and 33 converted to CDMS. MAGNIMS 2016 MRI criteria were fulfilled by 29, with 28 converting to CDMS. The sensitivity, specificity, accuracy, PPV, and NPV were 78%, 83%, 64%, 89%, and 69%, respectively, for the McDonald 2010 criteria, and 67%, 96%, 77%, 96%, and 62% for the MAGNIMS 2016 MRI criteria. MAGNIMS 2016 MRI criteria were superior to McDonald 2010 MRI criteria in specificity, accuracy, and PPV, but inferior in sensitivity and NPV. Copyright © 2018 Korean Neurological Association.

Investigation of subdural electrode displacement in invasive epilepsy surgery workup using neuronavigation and intraoperative MRI.

PubMed

Sommer, Bjoern; Rampp, Stefan; Doerfler, Arnd; Stefan, Hermann; Hamer, Hajo M; Buchfelder, Michael; Roessler, Karl

2018-06-19

One of the main obstacles of electrode implantation in epilepsy surgery is the electrode shift between implantation and the day of explantation. We evaluated this possible electrode displacement using intraoperative MRI (iopMRI) data and CT/MRI reconstruction. Thirteen patients (nine female, four male, median age 26 ± 9.4 years) suffering from drug-resistant epilepsy were examined. After implantation, the position of subdural electrodes was evaluated by 3.0 T-MRI and thin-slice CCT for 3D reconstruction. Localization of electrodes was performed with the volume-rendering technique. Post-implantation and pre-explantation 1.5 T-iopMRI scans were coregistered with the 3D reconstructions to determine the extent of electrode dislocation. Intraoperative MRI at the time of explantation revealed a relevant electrode shift in one patient (8%) of 10 mm. Median electrode displacement was 1.7 ± 2.6 mm with a coregistration error of 1.9 ± 0.7 mm. The median accuracy of the neuronavigation system was 2.2 ± 0.9 mm. Six of twelve patients undergoing resective surgery were seizure free (Engel class 1A, median follow-up 37.5 ± 11.8 months). Comparison of pre-explantation and post-implantation iopMRI scans with CT/MRI data using the volume-rendering technique resulted in an accurate placement of electrodes. In one patient with a considerable electrode dislocation, the surgical approach and extent was changed due to the detected electrode shift. ECoG: electrocorticography; EZ: epileptogenic zone; iEEG: invasive EEG; iopMRI: intraoperative MRI; MEG: magnetoencephalography; PET: positron emission tomography; SPECT: single photon emission computed tomography; 3D: three-dimensional.

Individual differences in personality traits reflect structural variance in specific brain regions.

PubMed

Gardini, Simona; Cloninger, C Robert; Venneri, Annalena

2009-06-30

Personality dimensions such as novelty seeking (NS), harm avoidance (HA), reward dependence (RD) and persistence (PER) are said to be heritable, stable across time and dependent on genetic and neurobiological factors. Recently a better understanding of the relationship between personality traits and brain structures/systems has become possible due to advances in neuroimaging techniques. This Magnetic Resonance Imaging (MRI) study investigated if individual differences in these personality traits reflected structural variance in specific brain regions. A large sample of eighty five young adult participants completed the Three-dimensional Personality Questionnaire (TPQ) and had their brain imaged with MRI. A voxel-based correlation analysis was carried out between individuals' personality trait scores and grey matter volume values extracted from 3D brain scans. NS correlated positively with grey matter volume in frontal and posterior cingulate regions. HA showed a negative correlation with grey matter volume in orbito-frontal, occipital and parietal structures. RD was negatively correlated with grey matter volume in the caudate nucleus and in the rectal frontal gyrus. PER showed a positive correlation with grey matter volume in the precuneus, paracentral lobule and parahippocampal gyrus. These results indicate that individual differences in the main personality dimensions of NS, HA, RD and PER, may reflect structural variance in specific brain areas.

Disrupted modular organization of resting-state cortical functional connectivity in U.S. military personnel following concussive ‘mild’ blast-related traumatic brain injury†

PubMed Central

Han, Kihwan; Mac Donald, Christine L.; Johnson, Ann M.; Barnes, Yolanda; Wierzechowski, Linda; Zonies, David; Oh, John; Flaherty, Stephen; Fang, Raymond; Raichle, Marcus E.; Brody, David L.

2013-01-01

Blast-related traumatic brain injury (TBI) has been one of the “signature injuries” of the wars in Iraq and Afghanistan. However, neuroimaging studies in concussive ‘mild’ blast-related TBI have been challenging due to the absence of abnormalities in computed tomography or conventional magnetic resonance imaging (MRI) and the heterogeneity of the blast-related injury mechanisms. The goal of this study was to address these challenges utilizing single-subject, module-based graph theoretic analysis of resting-state functional MRI (fMRI) data. We acquired 20 minutes of resting-state fMRI in 63 U.S. military personnel clinically diagnosed with concussive blast-related TBI and 21 U.S. military controls who had blast exposures but no diagnosis of TBI. All subjects underwent an initial scan within 90 days post-injury and 65 subjects underwent a follow-up scan 6 to 12 months later. A second independent cohort of 40 U.S. military personnel with concussive blast-related TBI patients served as a validation dataset. The second independent cohort underwent an initial scan within 30 days post-injury. 75% of scans were of good quality, with exclusions primarily due to excessive subject motion. Network analysis of the subset of these subjects in the first cohort with good quality scans revealed spatially localized reductions in participation coefficient, a measure of between-module connectivity, in the TBI patients relative to the controls at the time of the initial scan. These group differences were less prominent on the follow-up scans. The 15 brain areas with the most prominent reductions in participation coefficient were next used as regions of interest (ROIs) for single-subject analyses. In the first TBI cohort, more subjects than would be expected by chance (27/47 versus 2/47 expected, p < 0.0001) had 3 or more brain regions with abnormally low between-module connectivity relative to the controls on the initial scans. On the follow-up scans, more subjects than expected by chance (5/37, p = 0.044) but fewer subjects than on the initial scans had 3 or more brain regions with abnormally low between-module connectivity. Analysis of the second TBI cohort validation dataset with no free parameters provided a partial replication; again more subjects than expected by chance (8/31, p = 0.006) had 3 or more brain regions with abnormally low between-module connectivity on the initial scans, but the numbers were not significant (2/27, p = 0.276) on the follow-up scans. A single-subject, multivariate analysis by probabilistic principal component analysis of the between-module connectivity in the 15 identified ROIs, showed that 31/47 subjects in the first TBI cohort were found to be abnormal relative to the controls on the initial scans. In the second TBI cohort, 9/31 patients were found to be abnormal in identical multivariate analysis with no free parameters. Again, there were not substantial differences on the follow-up scans. Taken together, these results indicate that single-subject, module-based graph theoretic analysis of resting-state fMRI provides potentially useful information for concussive blast-related TBI if high quality scans can be obtained. The underlying biological mechanisms and consequences of disrupted between-module connectivity are unknown, thus further studies are required. PMID:23968735

Assessment of Biomarkers Associated with Joint Injury and Subsequent Post-Traumatic Arthritis

DTIC Science & Technology

2015-10-01

Post-traumatic arthritis, post-traumatic osteoarthritis, articular fracture, joint injury, trauma, biomarker, inflammation, MRI , knee, mouse model...will be collected prior to or at surgical intervention. MRI imaging of the injured knee will be obtained to assess the articular cartilage...and the development of PTA. We have successfully enrolled patients, collected and stored biosamples, obtained all post-operative MRI scans and are

Assessment of Biomarkers Associated with Joint Injury and Subsequent Post Traumatic Arthritis

DTIC Science & Technology

2015-10-01

arthritis, post-traumatic osteoarthritis, articular fracture, joint injury, trauma, biomarker, inflammation, MRI , knee, mouse model, translational...prior to or at surgical intervention. MRI imaging of the injured knee will be obtained to assess the articular cartilage. Degenerative changes in...development of PTA. We have successfully enrolled patients, collected and stored biosamples, obtained all post-operative MRI scans and are continuing to

SU-E-QI-19: Evaluation of a Clinical 1.5T MRI for Prostate Cancer MRS Imaging Using a In Vivo Tumor Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, X; Chen, L; Hensley, H

2014-06-15

Purpose: Magnetic resonance spectroscopic (MRS) imaging may provide important bio-markers to distinguish normal/cancerous prostate tissue. While MRS imaging requires a high uniform magnetic field, the ability of a clinical 1.5T MRI to achieve a comparable MRS signal is of interest for radiation treatment planning/assessment. This study is to evaluate the MRS imaging of a 1.5T clinical MRI for prostate cancers by comparing with a small animal 7T MRS scanner. Methods: A tumor model was developed by implanting LNCaP tumor cells in nude mice prostates. Tumor was monitored 3 weeks after implantation using MRI, and MRS imaging was performed on themore » tumor area when the tumor reached around 1cm in diameter. The 1.5T GE clinical MR scanner and the 7T Bruker small animal MR scanner were used for each mouse. MR spectrums acquired with these scanners were analyzed and compared. The signals of Choline and Citrate were considered. Results: The prostate tumor MR spectrum under the 1.5T clinical MRI showed a similar spectrum pattern to that acquired using the 7T animal MRI. The Choline signal (3.2ppm) is clear and there is no clear peak for Citrate (2.6ppm). However, the signal magnitude for Choline is not dominant compared to the background signal under 1.5T MRI. Typical cancerous prostate tissue MR spectrum with an increased Choline signal and a reduced Citrate signal was observed. In addition, signal variation is noticeable between repeated spectrum scans. The average of these scans showed a comparable and consistent spectrum to those under 7T MRI. Conclusion: The clinical 1.5T MRI is able to acquire a MR spectrum for prostate cancer comparable to those acquired using a dedicated 7T MRS scanner. However, to achieve a consistent and reliable spectrum, multiple repeated scans were necessary to get a statistical result and reduce the noise-induced artifact. This work was supported in part by the National Cancer Institute Grant R21 CA131979 and R01CA172638.« less

Safety of externally stimulated intracranial electrodes during functional MRI at 1.5T.

PubMed

Bhattacharyya, Pallab K; Mullin, Jeffery; Lee, Bryan S; Gonzalez-Martinez, Jorge A; Jones, Stephen E

2017-05-01

Surgical resection of the epileptogenic zone (EZ) is a potential cure for medically refractory focal epilepsy. Proper identification of the EZ is essential for such resection. Synergistic application of functional magnetic resonance imaging (fMRI) simultaneously with stimulation of a single externalized intracranial stereotactic EEG (SEEG) electrode has the potential to improve identification of the EZ. While most EEG-fMRI studies use the electrodes passively to record electrical activity, it is possible to stimulate the brain using the electrodes by connecting them with conducting cables to the stimulation hardware. In this study, we investigated the effect of MRI-induced heating on a single SEEG electrode and its sensitivity to geometry, configuration, and associated connections required for the stimulation. The temperature increase of a single electrode embedded within a gel phantom and connected to an external stimulation system was measured during 1.5T MRI scans using adjacent fluoroptic temperature sensors. A receive-only split-array head coil and a transmit-receive head coil were used for testing. Sequences included a standard localizer, T1-weighted axial fast low-angle shot (FLASH), gradient echo-planar imaging (GE-EPI) axial fMRI, and a high specific absorption rate T2-weighted turbo spin-echo (TSE) axial scan. Variations of the electrode location and connecting cable configuration were tested. No unacceptable heating was observed with the standard sequences used for evaluation of the EZ. Considerable heating (up to 14°C) was observed with the TSE sequence, which is not used clinically. The temperature increase was insignificant (<0.05°C) for electrode contacts closest to the isocenter and connecting cables lying along the isocenter, and varied with configurations of the connecting cable assembly. Simultaneous intracranial electrode stimulation during fMRI using an externalized stimulation system may be safe with strict adherence to settings tested prior to the fMRI. Localizer, FLASH, and GE-EPI fMRI may be safely performed in patients with a single SEEG electrode following the configurations tested in this study, but high SAR TSE scans should not be performed in these patients. Copyright © 2017 Elsevier Inc. All rights reserved.

TU-F-CAMPUS-J-02: Evaluation of Textural Feature Extraction for Radiotherapy Response Assessment of Early Stage Breast Cancer Patients Using Diffusion Weighted MRI and Dynamic Contrast Enhanced MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Y; Wang, C; Horton, J

Purpose: To investigate the feasibility of using classic textural feature extraction in radiotherapy response assessment, we studied a unique cohort of early stage breast cancer patients with paired pre - and post-radiation Diffusion Weighted MRI (DWI-MRI) and Dynamic Contrast Enhanced MRI (DCE-MRI). Methods: 15 female patients from our prospective phase I trial evaluating preoperative radiotherapy were included in this retrospective study. Each patient received a single-fraction radiation treatment, and DWI and DCE scans were conducted before and after the radiotherapy. DWI scans were acquired using a spin-echo EPI sequence with diffusion weighting factors of b = 0 and b =more » 500 mm{sup 2} /s, and the apparent diffusion coefficient (ADC) maps were calculated. DCE-MRI scans were acquired using a T{sub 1}-weighted 3D SPGR sequence with a temporal resolution of about 1 minute. The contrast agent (CA) was intravenously injected with a 0.1 mmol/kg bodyweight dose at 2 ml/s. Two parameters, volume transfer constant (K{sup trans} ) and k{sub ep} were analyzed using the two-compartment Tofts kinetic model. For DCE parametric maps and ADC maps, 33 textural features were generated from the clinical target volume (CTV) in a 3D fashion using the classic gray level co-occurrence matrix (GLCOM) and gray level run length matrix (GLRLM). Wilcoxon signed-rank test was used to determine the significance of each texture feature’s change after the radiotherapy. The significance was set to 0.05 with Bonferroni correction. Results: For ADC maps calculated from DWI-MRI, 24 out of 33 CTV features changed significantly after the radiotherapy. For DCE-MRI pharmacokinetic parameters, all 33 CTV features of K{sup trans} and 33 features of k{sub ep} changed significantly. Conclusion: Initial results indicate that those significantly changed classic texture features are sensitive to radiation-induced changes and can be used for assessment of radiotherapy response in breast cancer.« less

Safety and EEG data quality of concurrent high-density EEG and high-speed fMRI at 3 Tesla

PubMed Central

Foged, Mette Thrane; Lindberg, Ulrich; Vakamudi, Kishore; Larsson, Henrik B. W.; Pinborg, Lars H.; Kjær, Troels W.; Fabricius, Martin; Svarer, Claus; Ozenne, Brice; Thomsen, Carsten; Beniczky, Sándor; Posse, Stefan

2017-01-01

Purpose Concurrent EEG and fMRI is increasingly used to characterize the spatial-temporal dynamics of brain activity. However, most studies to date have been limited to conventional echo-planar imaging (EPI). There is considerable interest in integrating recently developed high-speed fMRI methods with high-density EEG to increase temporal resolution and sensitivity for task-based and resting state fMRI, and for detecting interictal spikes in epilepsy. In the present study using concurrent high-density EEG and recently developed high-speed fMRI methods, we investigate safety of radiofrequency (RF) related heating, the effect of EEG on cortical signal-to-noise ratio (SNR) in fMRI, and assess EEG data quality. Materials and methods The study compared EPI, multi-echo EPI, multi-band EPI and multi-slab echo-volumar imaging pulse sequences, using clinical 3 Tesla MR scanners from two different vendors that were equipped with 64- and 256-channel MR-compatible EEG systems, respectively, and receive only array head coils. Data were collected in 11 healthy controls (3 males, age range 18–70 years) and 13 patients with epilepsy (8 males, age range 21–67 years). Three of the healthy controls were scanned with the 256-channel EEG system, the other subjects were scanned with the 64-channel EEG system. Scalp surface temperature, SNR in occipital cortex and head movement were measured with and without the EEG cap. The degree of artifacts and the ability to identify background activity was assessed by visual analysis by a trained expert in the 64 channel EEG data (7 healthy controls, 13 patients). Results RF induced heating at the surface of the EEG electrodes during a 30-minute scan period with stable temperature prior to scanning did not exceed 1.0° C with either EEG system and any of the pulse sequences used in this study. There was no significant decrease in cortical SNR due to the presence of the EEG cap (p > 0.05). No significant differences in the visually analyzed EEG data quality were found between EEG recorded during high-speed fMRI and during conventional EPI (p = 0.78). Residual ballistocardiographic artifacts resulted in 58% of EEG data being rated as poor quality. Conclusion This study demonstrates that high-density EEG can be safely implemented in conjunction with high-speed fMRI and that high-speed fMRI does not adversely affect EEG data quality. However, the deterioration of the EEG quality due to residual ballistocardiographic artifacts remains a significant constraint for routine clinical applications of concurrent EEG-fMRI. PMID:28552957

Evaluation of Blalock-Taussig shunts in newborns: value of oblique MRI planes.

PubMed

Kastler, B; Livolsi, A; Germain, P; Zöllner, G; Dietemann, J L

1991-01-01

Eight infants with systemic-pulmonary Blalock-Taussig shunts were evaluated by spin-echo ECG-gated MRI. Contrary to Echocardiography, MRI using coronal oblique projections successfully visualized all palliative shunts entirely in one single plane (including one carried out on a right aberrant subclavian artery). MRI allowed assessment of size, course and patency of the shunt, including pulmonary and subclavian insertion. The proximal portion of the pulmonary and subclavian arteries were also visualized. We conclude that MRI with axial scans completed by coronal oblique planes is a promising, non invasive method for imaging the anatomical features of Blalock-Taussig shunts.

Long-term reproducibility of phantom signal intensities in nonuniformity corrected STIR-MRI examinations of skeletal muscle.

PubMed

Viddeleer, Alain R; Sijens, Paul E; van Ooijen, Peter M A; Kuypers, Paul D L; Hovius, Steven E R; Oudkerk, Matthijs

2009-08-01

Nerve regeneration could be monitored by comparing MRI image intensities in time, as denervated muscles display increased signal intensity in STIR sequences. In this study long-term reproducibility of STIR image intensity was assessed under clinical conditions and the required image intensity nonuniformity correction was improved by using phantom scans obtained at multiple positions. Three-dimensional image intensity nonuniformity was investigated in phantom scans. Next, over a three-year period, 190 clinical STIR hand scans were obtained using a standardized acquisition protocol, and corrected for intensity nonuniformity by using the results of phantom scanning. The results of correction with 1, 3, and 11 phantom scans were compared. The image intensities in calibration tubes close to the hands were measured every time to determine the reproducibility of our method. With calibration, the reproducibility of STIR image intensity improved from 7.8 to 6.4%. Image intensity nonuniformity correction with 11 phantom scans gave significantly better results than correction with 1 or 3 scans. The image intensities in clinical STIR images acquired at different times can be compared directly, provided that the acquisition protocol is standardized and that nonuniformity correction is applied. Nonuniformity correction is preferably based on multiple phantom scans.

Registering and Analyzing Rat fMRI Data in the Stereotaxic Framework by Exploiting Intrinsic Anatomical Features

PubMed Central

Lu, Hanbing; Scholl, Clara A.; Zuo, Yantao; Demny, Steven; Rea, William; Stein, Elliot A.; Yang, Yihong

2009-01-01

The value of analyzing neuroimaging data on a group level has been well established in human studies. However, there is no standard procedure for registering and analyzing fMRI data into common space in rodent functional magnetic resonance imaging (fMRI) studies. An approach for performing rat imaging data analysis in the stereotaxic framework is presented. This method is rooted in the biological observation that the skull shape and size of rat brain are essentially the same as long as their weights are within certain range. Registration is performed using rigid-body transformations without scaling or shearing, preserving the unique properties of the stable shape and size inherent in rat brain structure. Also, it does not require brain tissue masking, and is not biased towards surface coil sensitivity profile. A standard rat brain atlas is used to facilitate the identification of activated areas in common space, allowing accurate region-of-interest (ROI) analysis. This technique is evaluated from a group of rats (n = 11) undergoing routine MRI scans; the registration accuracy is estimated to be within 400 μm. The analysis of fMRI data acquired with an electrical forepaw stimulation model demonstrates the utility of this technique. The method is implemented within the AFNI framework and can be readily extended to other studies. PMID:19608368

The evidential value of developmental age imaging for assessing age of majority

PubMed Central

Cole, T. J.

2015-01-01

Abstract Aim: To consider the evidential value of developmental age images for identifying age of majority. Methods: The published literature on hand–wrist X-rays, MRI scans of the distal radius and orthopantomograms of the lower left third molar is considered in terms of the mean age of attainment of the adult appearance and the diagnostic test performance of the adult appearance to predict adult status, either administratively (under-17 football) or forensically. Results: The mean age of attainment of a mature hand-wrist X-ray is under 18 years and most individuals are mature before age 18. For the MRI wrist scan and the third molar the age of attainment is over 19 years and the adult appearance is an indicator of adulthood, while the immature appearance is uninformative about likely age. So MRI and third molars have high specificity, but low sensitivity. Conclusions: Bone age assessed by hand–wrist X-ray is uninformative and should not be used. The adult appearance of MRI wrist scans and third molars provide evidence of being over-age, although there remains a small risk of minors being misclassified as adult. The immature appearance is uninformative about likely age and, overall, more than one third of assessments are wrong. PMID:26133364

Concussion

MedlinePlus

... symptoms. They may test your senses, balance, reflexes, memory, and thinking. In some cases, the doctor will order tests to scan your brain. These include a computed tomography (CT) or magnetic resonance imaging (MRI) scan. They take a picture of your ...

Brain PET scan

MedlinePlus

... tissues are working. Other imaging tests, such as magnetic resonance imaging ( MRI ) and computed tomography ( CT ) scans only reveal ... M, Hellwig S, Kloppel S, Weiller C. Functional neuroimaging: functional magnetic resonance imaging, positron emission tomography, and single-photon emission computed ...

Use of various diagnostic methods in a patient with Gaucher disease type I.

PubMed

Farahati, J; Trenn, G; John-Mikolajewski, V; Zander, C; Pastores, G M; Sciuk, J; Reiners, C

1996-08-01

A series of plain radiographs, bone scans, bone marrow scans, and MRIs is reported in a patient with Gaucher disease type I, in whom two episodes of acute bone crisis developed during a 6-year period of follow-up. Acute bone crisis and global indolent bone marrow displacement could both be assessed by bone marrow scintigraphy, whereas MRI could better clarify the corti-comedullary alteration after bone infarction. Thus, MRI and bone marrow scintigraphy could be used as complementary imaging methods in the management of patients with Gaucher disease.

The convergence of maturational change and structural covariance in human cortical networks.

PubMed

Alexander-Bloch, Aaron; Raznahan, Armin; Bullmore, Ed; Giedd, Jay

2013-02-13

Large-scale covariance of cortical thickness or volume in distributed brain regions has been consistently reported by human neuroimaging studies. The mechanism of this population covariance of regional cortical anatomy has been hypothetically related to synchronized maturational changes in anatomically connected neuronal populations. Brain regions that grow together, i.e., increase or decrease in volume at the same rate over the course of years in the same individual, are thus expected to demonstrate strong structural covariance or anatomical connectivity across individuals. To test this prediction, we used a structural MRI dataset on healthy young people (N = 108; aged 9-22 years at enrollment), comprising 3-6 longitudinal scans on each participant over 6-12 years of follow-up. At each of 360 regional nodes, and for each participant, we estimated the following: (1) the cortical thickness in the median scan and (2) the linear rate of change in cortical thickness over years of serial scanning. We constructed structural and maturational association matrices and networks from these measurements. Both structural and maturational networks shared similar global and nodal topological properties, as well as mesoscopic features including a modular community structure, a relatively small number of highly connected hub regions, and a bias toward short distance connections. Using resting-state functional magnetic resonance imaging data on a subset of the sample (N = 32), we also demonstrated that functional connectivity and network organization was somewhat predictable by structural/maturational networks but demonstrated a stronger bias toward short distance connections and greater topological segregation. Brain structural covariance networks are likely to reflect synchronized developmental change in distributed cortical regions.

Reliability of a novel, semi-quantitative scale for classification of structural brain magnetic resonance imaging in children with cerebral palsy.

PubMed

Fiori, Simona; Cioni, Giovanni; Klingels, Katrjin; Ortibus, Els; Van Gestel, Leen; Rose, Stephen; Boyd, Roslyn N; Feys, Hilde; Guzzetta, Andrea

2014-09-01

To describe the development of a novel rating scale for classification of brain structural magnetic resonance imaging (MRI) in children with cerebral palsy (CP) and to assess its interrater and intrarater reliability. The scale consists of three sections. Section 1 contains descriptive information about the patient and MRI. Section 2 contains the graphical template of brain hemispheres onto which the lesion is transposed. Section 3 contains the scoring system for the quantitative analysis of the lesion characteristics, grouped into different global scores and subscores that assess separately side, regions, and depth. A larger interrater and intrarater reliability study was performed in 34 children with CP (22 males, 12 females; mean age at scan of 9 y 5 mo [SD 3 y 3 mo], range 4 y-16 y 11 mo; Gross Motor Function Classification System level I, [n=22], II [n=10], and level III [n=2]). Very high interrater and intrarater reliability of the total score was found with indices above 0.87. Reliability coefficients of the lobar and hemispheric subscores ranged between 0.53 and 0.95. Global scores for hemispheres, basal ganglia, brain stem, and corpus callosum showed reliability coefficients above 0.65. This study presents the first visual, semi-quantitative scale for classification of brain structural MRI in children with CP. The high degree of reliability of the scale supports its potential application for investigating the relationship between brain structure and function and examining treatment response according to brain lesion severity in children with CP. © 2014 Mac Keith Press.

Individualized Gaussian process-based prediction and detection of local and global gray matter abnormalities in elderly subjects.

PubMed

Ziegler, G; Ridgway, G R; Dahnke, R; Gaser, C

2014-08-15

Structural imaging based on MRI is an integral component of the clinical assessment of patients with potential dementia. We here propose an individualized Gaussian process-based inference scheme for clinical decision support in healthy and pathological aging elderly subjects using MRI. The approach aims at quantitative and transparent support for clinicians who aim to detect structural abnormalities in patients at risk of Alzheimer's disease or other types of dementia. Firstly, we introduce a generative model incorporating our knowledge about normative decline of local and global gray matter volume across the brain in elderly. By supposing smooth structural trajectories the models account for the general course of age-related structural decline as well as late-life accelerated loss. Considering healthy subjects' demography and global brain parameters as informative about normal brain aging variability affords individualized predictions in single cases. Using Gaussian process models as a normative reference, we predict new subjects' brain scans and quantify the local gray matter abnormalities in terms of Normative Probability Maps (NPM) and global z-scores. By integrating the observed expectation error and the predictive uncertainty, the local maps and global scores exploit the advantages of Bayesian inference for clinical decisions and provide a valuable extension of diagnostic information about pathological aging. We validate the approach in simulated data and real MRI data. We train the GP framework using 1238 healthy subjects with ages 18-94 years, and predict in 415 independent test subjects diagnosed as healthy controls, Mild Cognitive Impairment and Alzheimer's disease. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Individualized Gaussian process-based prediction and detection of local and global gray matter abnormalities in elderly subjects

PubMed Central

Ziegler, G.; Ridgway, G.R.; Dahnke, R.; Gaser, C.

2014-01-01

Structural imaging based on MRI is an integral component of the clinical assessment of patients with potential dementia. We here propose an individualized Gaussian process-based inference scheme for clinical decision support in healthy and pathological aging elderly subjects using MRI. The approach aims at quantitative and transparent support for clinicians who aim to detect structural abnormalities in patients at risk of Alzheimer's disease or other types of dementia. Firstly, we introduce a generative model incorporating our knowledge about normative decline of local and global gray matter volume across the brain in elderly. By supposing smooth structural trajectories the models account for the general course of age-related structural decline as well as late-life accelerated loss. Considering healthy subjects' demography and global brain parameters as informative about normal brain aging variability affords individualized predictions in single cases. Using Gaussian process models as a normative reference, we predict new subjects' brain scans and quantify the local gray matter abnormalities in terms of Normative Probability Maps (NPM) and global z-scores. By integrating the observed expectation error and the predictive uncertainty, the local maps and global scores exploit the advantages of Bayesian inference for clinical decisions and provide a valuable extension of diagnostic information about pathological aging. We validate the approach in simulated data and real MRI data. We train the GP framework using 1238 healthy subjects with ages 18–94 years, and predict in 415 independent test subjects diagnosed as healthy controls, Mild Cognitive Impairment and Alzheimer's disease. PMID:24742919

Bone erosions in patients with chronic gouty arthropathy are associated with tophi but not bone oedema or synovitis: new insights from a 3 T MRI study.

PubMed

McQueen, Fiona M; Doyle, Anthony; Reeves, Quentin; Gao, Angela; Tsai, Amy; Gamble, Greg D; Curteis, Barbara; Williams, Megan; Dalbeth, Nicola

2014-01-01

Bone erosion has been linked with tophus deposition in gout but the roles of osteitis (MRI bone oedema) and synovitis remain uncertain. Our aims in this prospective 3 T MRI study were to investigate the frequency of these features in gout and determine their relation to one another. 3 T MRI scans of the wrist were obtained in 40 gout patients. Scans were scored independently by two radiologists for bone oedema, erosions, tophi and synovitis. Dual-energy CT (DECT) scans were scored for tophi in a subgroup of 10 patients. Interreader reliability was high for erosions and tophi [intraclass correlation coefficients (ICCs) 0.77 (95% CI 0.71, 0.87) and 0.71 (95% CI 0.52, 0.83)] and moderate for bone oedema [ICC = 0.60 (95% CI 0.36, 0.77)]. Compared with DECT, MRI had a specificity of 0.98 (95% CI 0.93, 0.99) and sensitivity of 0.63 (95% CI 0.48, 0.76) for tophi. Erosions were detected in 63% of patients and were strongly associated with tophi [odds ratio (OR) = 13.0 (95% CI 1.5, 113)]. In contrast, no association was found between erosions and bone oedema. Using concordant data, bone oedema was scored at 6/548 (1%) sites in 5/40 patients (12.5%) and was very mild (median carpal score = 1, maximum = 45). In logistic regression analysis across all joints nested within individuals, tophus, but not synovitis, was independently associated with erosion [OR = 156.5 (21.2, >999.9), P < 0.0001]. Erosions were strongly associated with tophi but not bone oedema or synovitis. MRI bone oedema was relatively uncommon and low grade. These findings highlight the unique nature of the osteopathology of gout.

[Relevance of MRI After Closed Reduction of Traumatic Hip Dislocation in Children].

PubMed

Strüwind, Christoph Mauritz; von Rüden, Christian; Thannheimer, Andreas; Bühren, Volker; Schneidmueller, Dorien

2018-05-14

Traumatic hip dislocation in children and adolescents is a rare entity that typically results from high-energy trauma. After closed joint reduction, further treatment depends on the specific pattern of the lesion as identified using cross sectional imaging. The aim of this retrospective analysis was to evaluate relevant side effects after traumatic hip dislocation in children and adolescents in order to examine the need for focused diagnostics. This retrospective analysis covered 8 adolescents under 18 years suffering isolated traumatic hip joint dislocation between 2001 and 2017. In all patients, closed joint reduction was performed immediately after admission to the emergency room. In order to evaluate the complete extent of the injury, 5 patients received an MRI and 3 patients a CT scan following closed joint reduction. Two female and 6 male patients with a median age of 11 (range 5 - 16) years were included. In 2 cases, a free joint body was detected in the posterior joint gap in the posttraumatic CT scan after closed joint reduction. Interposition of the labrum into the joint gap was detected intraoperatively in both cases. In one patient who received posttraumatic MRI, labral interposition into the joint gap was observed after closed reduction. These findings were confirmed intraoperatively. In 4 other patients, no posttraumatic labral lesion was detected in the MRI after closed reduction. The reported side effects included ruptured anterior inferior iliac spine and ruptured femoral head ligament. MRI is gaining increasing importance following traumatic hip dislocation in children and adolescents. A missing chondral or osteochondral fragment in the CT scan does not exclude a labral lesion or interposition. Therefore, MRI following closed reduction is mandatory in any case. Georg Thieme Verlag KG Stuttgart · New York.

Multiparametric prostate MRI: technical conduct, standardized report and clinical use.

PubMed

Manfredi, Matteo; Mele, Fabrizio; Garrou, Diletta; Walz, Jochen; Fütterer, Jurgen J; Russo, Filippo; Vassallo, Lorenzo; Villers, Arnauld; Emberton, Mark; Valerio, Massimo

2018-02-01

Multiparametric prostate MRI (mp-MRI) is an emerging imaging modality for diagnosis, characterization, staging, and treatment planning of prostate cancer (PCa). The technique, results reporting, and its role in clinical practice have been the subject of significant development over the last decade. Although mp-MRI is not yet routinely used in the diagnostic pathway, almost all urological guidelines have emphasized the potential role of mp-MRI in several aspects of PCa management. Moreover, new MRI sequences and scanning techniques are currently under evaluation to improve the diagnostic accuracy of mp-MRI. This review presents an overview of mp-MRI, summarizing the technical applications, the standardized reporting systems used, and their current roles in various stages of PCa management. Finally, this critical review also reports the main limitations and future perspectives of the technique.

Towards a Teleoperated Needle Driver Robot with Haptic Feedback for RFA of Breast Tumors under Continuous MRI1

PubMed Central

Kokes, Rebecca; Lister, Kevin; Gullapalli, Rao; Zhang, Bao; MacMillan, Alan; Richard, Howard; Desai, Jaydev P.

2009-01-01

Objective The purpose of this paper is to explore the feasibility of developing a MRI-compatible needle driver system for radiofrequency ablation (RFA) of breast tumors under continuous MRI imaging while being teleoperated by a haptic feedback device from outside the scanning room. The developed needle driver prototype was designed and tested for both tumor targeting capability as well as RFA. Methods The single degree-of-freedom (DOF) prototype was interfaced with a PHANToM haptic device controlled from outside the scanning room. Experiments were performed to demonstrate MRI-compatibility and position control accuracy with hydraulic actuation, along with an experiment to determine the PHANToM’s ability to guide the RFA tool to a tumor nodule within a phantom breast tissue model while continuously imaging within the MRI and receiving force feedback from the RFA tool. Results Hydraulic actuation is shown to be a feasible actuation technique for operation in an MRI environment. The design is MRI-compatible in all aspects except for force sensing in the directions perpendicular to the direction of motion. Experiments confirm that the user is able to detect healthy vs. cancerous tissue in a phantom model when provided with both visual (imaging) feedback and haptic feedback. Conclusion The teleoperated 1-DOF needle driver system presented in this paper demonstrates the feasibility of implementing a MRI-compatible robot for RFA of breast tumors with haptic feedback capability. PMID:19303805

Acute vertigo in an anesthesia provider during exposure to a 3T MRI scanner

PubMed Central

Gorlin, Andrew; Hoxworth, Joseph M; Pavlicek, William; Thunberg, Christopher A; Seamans, David

2015-01-01

Vertigo induced by exposure to the magnetic field of a magnetic resonance imaging (MRI) scanner is a well-known phenomenon within the radiology community but is not widely appreciated by other clinical specialists. Here, we describe a case of an anesthetist experiencing acute vertigo while providing sedation to a patient undergoing a 3 Tesla MRI scan. After discussing previous reports, and the evidence surrounding MRI-induced vertigo, we review potential etiologies that include the effects of both static and time-varying magnetic fields on the vestibular apparatus. We conclude our review by discussing the occupational standards that exist for MRI exposure and methods to minimize the risks of MRI-induced vertigo for clinicians working in the MRI environment. PMID:25792858

Brain changes following four weeks of unimanual motor training: Evidence from fMRI-guided diffusion MRI tractography.

PubMed

Reid, Lee B; Sale, Martin V; Cunnington, Ross; Mattingley, Jason B; Rose, Stephen E

2017-09-01

We have reported reliable changes in behavior, brain structure, and function in 24 healthy right-handed adults who practiced a finger-thumb opposition sequence task with their left hand for 10 min daily, over 4 weeks. Here, we extend these findings by using diffusion MRI to investigate white-matter changes in the corticospinal tract, basal-ganglia, and connections of the dorsolateral prefrontal cortex. Twenty-three participant datasets were available with pre-training and post-training scans. Task performance improved in all participants (mean: 52.8%, SD: 20.0%; group P < 0.01 FWE) and widespread microstructural changes were detected across the motor system of the "trained" hemisphere. Specifically, region-of-interest-based analyses of diffusion MRI (n = 22) revealed significantly increased fractional anisotropy (FA) in the right caudate nucleus (4.9%; P < 0.05 FWE), and decreased mean diffusivity in the left nucleus accumbens (-1.3%; P < 0.05 FWE). Diffusion MRI tractography (n = 22), seeded by sensorimotor cortex fMRI activation, also revealed increased FA in the right corticospinal tract (mean 3.28%; P < 0.05 FWE) predominantly reflecting decreased radial diffusivity. These changes were consistent throughout the entire length of the tract. The left corticospinal tract did not show any changes. FA also increased in white matter connections between the right middle frontal gyrus and both right caudate nucleus (17/22 participants; P < 0.05 FWE) and right supplementary motor area (18/22 participants; P < 0.05 FWE). Equivalent changes in FA were not seen in the left (non-trained) hemisphere. In combination with our functional and structural findings, this study provides detailed, multifocal evidence for widespread neuroplastic changes in the human brain resulting from motor training. Hum Brain Mapp 38:4302-4312, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Assessing the clinical effect of residual cortical disconnection after ischemic strokes.

PubMed

Bonilha, Leonardo; Rorden, Chris; Fridriksson, Julius

2014-04-01

Studies assessing the relationship between chronic poststroke language impairment (aphasia) and ischemic brain damage usually rely on measuring the extent of brain necrosis observed on MRI. Nonetheless, clinical observation suggests that patients can exhibit deficits that are more severe than what would be expected based on lesion location and size. This phenomenon is commonly explained as being the result of cortical disconnection. To understand whether disconnection contributes to clinical symptoms, we assessed the relationship between language impairments and structural brain connectivity (the connectome) in patients with chronic aphasia after a stroke. Thirty-nine patients with chronic aphasia underwent language assessment and MRI scanning. Relying on MRI data, we reconstructed the individual connectome from T1-weighted and diffusion tensor imaging. Deterministic fiber tractography was used to assess connectivity between each possible pair of cortical Brodmann areas. Multiple linear regression analyses were performed to evaluate the relationship between language performance and cortical necrosis and cortical disconnection. We observed that structural disconnection of Brodmann area 45 (spared by the necrotic tissue) was independently associated with naming performance, controlling for the extent of Brodmann area 45 necrosis (F=4.62; P<0.01; necrosis: β=0.43; P=0.03; disconnection β=1.21; P<0.001). We suggest that cortical disconnection, as measured by the structural connectome, is an independent predictor of naming impairment in patients with chronic aphasia. The full extent of clinically relevant brain damage after an ischemic stroke may be underappreciated by visual inspection of cortical necrosis alone.

"Power-on resets" in cardiac implantable electronic devices during magnetic resonance imaging.

PubMed

Higgins, John V; Sheldon, Seth H; Watson, Robert E; Dalzell, Connie; Acker, Nancy; Cha, Yong-Mei; Asirvatham, Samuel J; Kapa, Suraj; Felmlee, Joel P; Friedman, Paul A

2015-03-01

Magnetic resonance imaging (MRI) has been safely performed in some patients with cardiac implantable electronic devices (CIEDs) under careful monitoring and prespecified conditions. Pacemaker-dependent patients are often excluded, partly because of the potential for "power-on reset" (PoR), which can lead to a change from asynchronous to inhibited pacing with consequent inhibition of pacing due to electromagnetic interference during MRI. The purpose of this study was to review risk factors for PoR during MRI. A prospective study was performed between January 2008 and May 2013 in patients with CIEDs undergoing clinically indicated MRI. Eligible patients were not pacemaker dependent. Devices were interrogated before and after MRI, programmed to an asynchronous mode or an inhibition mode with tachyarrhythmia therapies turned off, and reprogrammed to their original settings after MRI. MRI scans (n = 256) were performed in 198 patients with non-MRI-conditional CIEDs between 2008 and 2013 (median age 66 years; interquartile range 57-77 years; 59% men). PoR occurred during 9 MRI scans (3.5%) in 8 patients. PoR was more frequent with Medtronic devices than with other generator brands (n = 9/139 vs 0/117 [6% vs 0%]; P = .005). Devices with PoR were all released before 2002 and were implanted from 1999 to 2004. Effects of PoR included a decrease in heart rate during MRI (n = 4) and transient anomalous battery life indication (n = 1). All devices functioned normally after MRI. PoR occurs infrequently but can cause deleterious changes in pacing mode and heart rate. MRI should not be performed in pacemaker-dependent patients with older at-risk generators. Continuous monitoring during MRI is essential because unrecognized PoR may inhibit pacing or accelerate battery depletion due to high pacing output. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

MRI scout images can detect the acute intracerebral hemorrhage on CT.

PubMed

Hayashi, Toshiyuki; Aoki, Junya; Suzuki, Kentaro; Sakamoto, Yuki; Suda, Satoshi; Okubo, Seiji; Mishina, Masahiro; Kimura, Kazumi

2018-04-15

Magnetic resonance imaging (MRI) has recently emerged as a first-line tool for investigating acute stroke. However, MRI requires long scan times, which could be detrimental for severe stroke patients with a large intracerebral hemorrhage (ICH). MRI scout images, which are taken prior to a study to determine the range of subsequent images, can be used to rapidly screen the whole brain. We examined whether MRI scout imaging can detect ICHs observed by computed tomography (CT). Between September 2014 and March 2016, consecutive acute ICH patients who underwent both MRI scout and CT imaging in the acute setting were studied. ICHs on MRI scout images were defined as space-occupying lesions. Two neurologists independently assessed the scout images. We investigated whether ICHs on CT scans can be detected on MRI scout images and the characteristics of ICHs not detected by MRI scout images. One hundred and forty-eight ICH patients (median age, 68 [interquartile range, 59-77] years; 99 [67%] males; median National Institutes of Health Stroke Scale score, 11 [4-17]) were enrolled. Among these, 138 (93%) patients were diagnosed as having ICH by MRI scout imaging (positive group), and 10 (7%) patients were not (negative group). The bleeding volume was 9.3 [4.5-22.4] ml in the positive group and 1.0 [0.4-2.0] ml in the negative group (p < .001). The cut-off value of bleeding volume calculated from the receiver operating characteristic curve was 2.0 ml. Regarding ICH lesions, 4 (44%) of the 9 pontine hemorrhages were detected on MRI scout images, whereas 134 (96%) of the 139 other hemorrhages were diagnosed (p < .001). We diagnosed >90% of ICHs using MRI scout images. Low levels of ICH and pontine hemorrhaging might be difficult to detect using MRI scout imaging. Copyright © 2018 Elsevier B.V. All rights reserved.

Subcortical shape and volume abnormalities in an elderly HIV+ cohort

NASA Astrophysics Data System (ADS)

Wade, Benjamin S. C.; Valcour, Victor; Busovaca, Edgar; Esmaeili-Firidouni, Pardis; Joshi, Shantanu H.; Wang, Yalin; Thompson, Paul M.

2015-03-01

Over 50% of HIV+ individuals show significant impairment in psychomotor functioning, processing speed, working memory and attention [1, 2]. Patients receiving combination antiretroviral therapy may still have subcortical atrophy, but the profile of HIV-associated brain changes is poorly understood. With parametric surface-based shape analyses, we mapped the 3D profile of subcortical morphometry in 63 elderly HIV+ subjects (4 female; age=65.35 ± 2.21) and 31 uninfected elderly controls (2 female; age=64.68 ± 4.57) scanned with MRI as part of a San Francisco Bay Area study of elderly people with HIV. We also investigated whether morphometry was associated with nadir CD4+ (T-cell) counts, viral load and illness duration among HIV+ participants. FreeSurfer was used to segment the thalamus, caudate, putamen, pallidum, hippocampus, amygdala, accumbens, brainstem, callosum and ventricles from brain MRI scans. To study subcortical shape, we analyzed: (1) the Jacobian determinant (JD) indexed over structures' surface coordinates and (2) radial distances (RD) of structure surfaces from a medial curve. A JD less than 1 reflects regional tissue atrophy and greater than 1 reflects expansion. The volumes of several subcortical regions were found to be associated with HIV status. No regional volumes showed detectable associations with CD4 counts, viral load or illness duration. The shapes of numerous subcortical regions were significantly linked to HIV status, detectability of viral RNA and illness duration. Our results show subcortical brain differences in HIV+ subjects in both shape and volumetric domains.

WE-G-BRD-01: Diffusion Weighted MRI for Response Assessment of Inoperable Lung Tumors for Patients Undergoing SBRT Treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tyagi, N; Wengler, K; Yorke, E

2014-06-15

Purpose: To investigate early changes in tumor Apparent Diffusion Coefficients derived from diffusion weighted (DW)-MRI of lung cancer patients undergoing SBRT, as a possible early predictor of treatment response. Methods: DW-MRI scans were performed in this prospective phase I IRB-approved study of inoperable lung tumors at various time-points during the course of SBRT treatments. Axial DW scan using multi b-values ranging from 0–1000 s/mm{sup 2} were acquired in treatment position on a 3T Philips MR scanner during simulation, one hour after the first fraction (8 Gy), after a total of 5 fractions (40 Gy) and 4 weeks after SBRT delivery.more » A monoexponential model based on a least square fit from all b values was performed on a pixel-by-pixel basis and ADC was calculated. GTVs drawn on 4DCT for planning were mapped on the T2w MRI (acquired at exhale) after deformable registration. These volumes were then mapped on DWI scan for ADC calculation after rigid registration between the anatomical scan and diffusion scan. T2w scan on followup time points were deformably registered to the pretreatment T2 scan. Results: The first two patients in this study were analyzed. Median ADC values were 1.48, 1.48, 1.62 and 1.83 (10{sup −3}×) mm{sup 2}/s at pretreatment, after 8 Gy, after 40 Gy and 4 weeks posttreatment for the first patient and 1.57, 1.53, 1.66 and 1.72 (10{sup −3}×) mm{sup 2}/s for the second patient. ADC increased more significantly after 4 weeks of treatment rather than immediately post treatment, implying that late ADC value may be a better predictor of tumor response for SBRT treatment. The fraction of tumor pixels at high ADC values increased at 4 weeks post treatment. Conclusion: The observed increase in ADC values before the end of radiotherapy may be a surrogate for tumor response, but further patient accrual will be necessary to determine its value.« less

The Brainomics/Localizer database.

PubMed

Papadopoulos Orfanos, Dimitri; Michel, Vincent; Schwartz, Yannick; Pinel, Philippe; Moreno, Antonio; Le Bihan, Denis; Frouin, Vincent

2017-01-01

The Brainomics/Localizer database exposes part of the data collected by the in-house Localizer project, which planned to acquire four types of data from volunteer research subjects: anatomical MRI scans, functional MRI data, behavioral and demographic data, and DNA sampling. Over the years, this local project has been collecting such data from hundreds of subjects. We had selected 94 of these subjects for their complete datasets, including all four types of data, as the basis for a prior publication; the Brainomics/Localizer database publishes the data associated with these 94 subjects. Since regulatory rules prevent us from making genetic data available for download, the database serves only anatomical MRI scans, functional MRI data, behavioral and demographic data. To publish this set of heterogeneous data, we use dedicated software based on the open-source CubicWeb semantic web framework. Through genericity in the data model and flexibility in the display of data (web pages, CSV, JSON, XML), CubicWeb helps us expose these complex datasets in original and efficient ways. Copyright © 2015 Elsevier Inc. All rights reserved.

Diagnosis and surgical outcomes of intraparotid facial nerve schwannoma showing normal facial nerve function.

PubMed

Lee, D W; Byeon, H K; Chung, H P; Choi, E C; Kim, S-H; Park, Y M

2013-07-01

The findings of intraparotid facial nerve schwannoma (FNS) using preoperative diagnostic tools, including ultrasonography (US)-guided fine needle aspiration biopsy, computed tomography (CT) scan, and magnetic resonance imaging (MRI), were analyzed to determine if there are any useful findings that might suggest the presence of a lesion. Treatment guidelines are suggested. The medical records of 15 patients who were diagnosed with an intraparotid FNS were retrospectively analyzed. US and CT scans provide clinicians with only limited information; gadolinium enhanced T1-weighted images from MRI provide more specific findings. Tumors could be removed successfully with surgical exploration, preserving facial nerve function at the same time. Gadolinium-enhanced T1-weighted MRI showed more characteristic findings for the diagnosis of intraparotid FNS. Intraparotid FNS without facial palsy can be diagnosed with MRI preoperatively, and surgical exploration is a suitable treatment modality which can remove the tumor and preserve facial nerve function. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Echo planar imaging at 4 Tesla with minimum acoustic noise.

PubMed

Tomasi, Dardo G; Ernst, Thomas

2003-07-01

To minimize the acoustic sound pressure levels of single-shot echo planar imaging (EPI) acquisitions on high magnetic field MRI scanners. The resonance frequencies of gradient coil vibrations, which depend on the coil length and the elastic properties of the materials in the coil assembly, were measured using piezoelectric transducers. The frequency of the EPI-readout train was adjusted to avoid the frequency ranges of mechanical resonances. Our MRI system exhibited two sharp mechanical resonances (at 720 and 1220 Hz) that can increase vibrational amplitudes up to six-fold. A small adjustment of the EPI-readout frequency made it possible to reduce the sound pressure level of EPI-based perfusion and functional MRI scans by 12 dB. Normal vibrational modes of MRI gradient coils can dramatically increase the sound pressure levels during echo planar imaging (EPI) scans. To minimize acoustic noise, the frequency of EPI-readout trains and the resonance frequencies of gradient coil vibrations need to be different. Copyright 2003 Wiley-Liss, Inc.

SU-E-J-192: Verification of 4D-MRI Internal Target Volume Using Cine MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lafata, K; Czito, B; Palta, M

Purpose: To investigate the accuracy of 4D-MRI in determining the Internal Target Volume (ITV) used in radiation oncology treatment planning of liver cancers. Cine MRI is used as the standard baseline in establishing the feasibility and accuracy of 4D-MRI tumor motion within the liver. Methods: IRB approval was obtained for this retrospective study. Analysis was performed on MR images from four patients receiving external beam radiation therapy for liver cancer at our institution. Eligible patients received both Cine and 4D-MRI scans before treatment. Cine images were acquired sagittally in real time at a slice bisecting the tumor, while 4D imagesmore » were acquired volumetrically. Cine MR DICOM headers were manipulated such that each respiratory frame was assigned a unique slice location. This approach permitted the treatment planning system (Eclipse, Varian Medical Systems) to recognize a complete respiratory cycle as a “volume”, where the gross tumor was contoured temporally. Software was developed to calculate the union of all frame contours in the structure set, resulting in the corresponding plane of the ITV projecting through the middle of the tumor, defined as the Internal Target Area (ITA). This was repeated for 4D-MRI, at the corresponding slice location, allowing a direct comparison of ITAs obtained from each modality. Results: Four patients have been analyzed. ITAs contoured from 4D-MRI correlate with contours from Cine MRI. The mean error of 4D values relative to Cine values is 7.67 +/− 2.55 %. No single ITA contoured from 4D-MRI demonstrated more than 10.5 % error compared to its Cine MRI counterpart. Conclusion: Motion management is a significant aspect of treatment planning within dynamic environments such as the liver, where diaphragmatic and cardiac activity influence plan accuracy. This small pilot study suggests that 4D-MRI based ITA measurements agree with Cine MRI based measurements, an important step towards clinical implementation. NIH 1R21CA165384-01A1.« less

Is hunger important to model in fMRI visual food-cue reactivity paradigms in adults with obesity and how should this be done?

PubMed

Chin, Shao-Hua; Kahathuduwa, Chanaka N; Stearns, Macy B; Davis, Tyler; Binks, Martin

2018-01-01

We considered 1) influence of self-reported hunger in behavioral and fMRI food-cue reactivity (fMRI-FCR) 2) optimal methods to model this. Adults (N = 32; 19-60 years; F = 21; BMI 30-39.9 kg/m 2 ) participated in an fMRI-FCR task that required rating 240 images of food and matched objects for 'appeal'. Hunger, satiety, thirst, fullness and emptiness were measured pre- and post-scan (visual analogue scales). Hunger, satiety, fullness and emptiness were combined to form a latent factor (appetite). Post-vs. pre-scores were compared using paired t-tests. In mixed-effects models, appeal/fMRI-FCR responses were regressed on image (i.e. food/objects), with random intercepts and slopes of image for functional runs nested within subjects. Each of hunger, satiety, thirst, fullness, emptiness and appetite were added as covariates in 4 forms (separate models): 1) change; 2) post- and pre-mean; 3) pre-; 4) change and pre-. Satiety decreased (Δ = -13.39, p = 0.001) and thirst increased (Δ = 11.78, p = 0.006) during the scan. Changes in other constructs were not significant (p's > 0.05). Including covariates did not influence food vs. object contrast of appeal ratings/fMRI-FCR. Significant image X covariate interactions were observed in some fMRI models. However, including these constructs did not improve the overall model fit. While some subjective, self-reported hunger, satiety and related constructs may be moderating fMRI-FCR, these constructs do not appear to be salient influences on appeal/fMRI-FCR in people with obesity undergoing fMRI. Copyright © 2017 Elsevier Ltd. All rights reserved.

Magnetic resonance imaging in evaluating workers' compensation patients.

PubMed

Babbel, Daniel; Rayan, Ghazi

2012-04-01

We studied the utility of magnetic resonance imaging (MRI) studies for workers' compensation patients with hand conditions in which the referring doctor obtained the images. We compared the MRI findings with the eventual clinical findings. We also investigated the approximate cost of these MRI studies. We retrospectively reviewed the charts of all workers' compensation patients seen in a hand and upper extremity practice over the course of 3 years. We selected patients who had MRI studies of the affected upper extremities before referral to the senior author (G.R.). We reviewed the charts for information regarding demographics, referral diagnoses, MRI diagnoses made by the radiologist, the area of the upper extremity studied, and eventual clinical diagnoses by the senior author. We made a determination as to whether a hand surgeon could have adequately diagnosed and treated the patients' conditions without the imaging studies. We also investigated the cost associated with these MRIs. We included 62 patients with a total of 67 MRI scans in this study. The MRI studies did not contribute to clinically diagnosing the patients' conditions in any of the cases we reviewed. The hand surgeon's clinical diagnosis disagreed with the radiologist's MRI diagnosis in 63% of patients. The MRI was unnecessary to arrive at the clinical diagnosis and did not influence the treatment offered for any of the 62 patients. The total cost for the 67 non-contrast MRI studies was approximately $53,000. Costly imaging studies are frequently done to determine the validity of a patient's reported problems; unfortunately, these tests are frequently unnecessary and waste resources. Magnetic resonance imaging scans may not be the standard for accurate diagnosis and can misdirect care. Therapeutic III. Copyright © 2012 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

National implementation of multi-parametric magnetic resonance imaging for prostate cancer detection - recommendations from a UK consensus meeting.

PubMed

Brizmohun Appayya, Mrishta; Adshead, Jim; Ahmed, Hashim U; Allen, Clare; Bainbridge, Alan; Barrett, Tristan; Giganti, Francesco; Graham, John; Haslam, Phil; Johnston, Edward W; Kastner, Christof; Kirkham, Alexander P S; Lipton, Alexandra; McNeill, Alan; Moniz, Larissa; Moore, Caroline M; Nabi, Ghulam; Padhani, Anwar R; Parker, Chris; Patel, Amit; Pursey, Jacqueline; Richenberg, Jonathan; Staffurth, John; van der Meulen, Jan; Walls, Darren; Punwani, Shonit

2018-07-01

To identify areas of agreement and disagreement in the implementation of multi-parametric magnetic resonance imaging (mpMRI) of the prostate in the diagnostic pathway. Fifteen UK experts in prostate mpMRI and/or prostate cancer management across the UK (involving nine NHS centres to provide for geographical spread) participated in a consensus meeting following the Research and Development Corporation and University of California-Los Angeles (UCLA-RAND) Appropriateness Method, and were moderated by an independent chair. The experts considered 354 items pertaining to who can request an mpMRI, prostate mpMRI protocol, reporting guidelines, training, quality assurance (QA) and patient management based on mpMRI levels of suspicion for cancer. Each item was rated for agreement on a 9-point scale. A panel median score of ≥7 constituted 'agreement' for an item; for an item to reach 'consensus', a panel majority scoring was required. Consensus was reached on 59% of items (208/354); these were used to provide recommendations for the implementation of prostate mpMRI in the UK. Key findings include prostate mpMRI requests should be made in consultation with the urological team; mpMRI scanners should undergo QA checks to guarantee consistently high diagnostic quality scans; scans should only be reported by trained and experienced radiologists to ensure that men with unsuspicious prostate mpMRI might consider avoiding an immediate biopsy. Our consensus statements demonstrate a set of criteria that are required for the practical dissemination of consistently high-quality prostate mpMRI as a diagnostic test before biopsy in men at risk. © 2018 The Authors BJU International published by John Wiley & Sons Ltd on behalf of BJU International.

Virtual Humans for Implantable Device Safety Assessment in MRI: Mitigating Magnetic Resonance Imaging Hazards for Implanted Medical Devices.

PubMed

Brown, James E; Qiang, Rui; Stadnik, Paul J; Stotts, Larry J; Von Arx, Jeffrey A

2017-01-01

Magnetic resonance imaging (MRI) is the preferred modality for soft tissue imaging because of its nonionizing radiation and lack of contrast agent. Due to interactions between the MR system and active implantable medical devices (AIMDs), patients with implants such as pacemakers are generally denied access to MRI, which presents a detriment to that population. It has been estimated that 50-75% of patients with a cardiac device were denied access to MRI scanning and, moreover, that 17% of pacemaker patients need an MRI within 12 months of implantation [1]. In recent years, AIMD manufacturers, such as Biotronik, have assessed the conditional safety of devices in MRI.

Interactive 3D visualization tools for stereotactic atlas-based functional neurosurgery

NASA Astrophysics Data System (ADS)

St. Jean, Philippe; Kasrai, Reza; Clonda, Diego; Sadikot, Abbas F.; Evans, Alan C.; Peters, Terence M.

1998-06-01

Many of the critical basal ganglia structures are not distinguishable on anatomical magnetic resonance imaging (MRI) scans, even though they differ in functionality. In order to provide the neurosurgeon with this missing information, a deformable volumetric atlas of the basal ganglia has been created from the Shaltenbrand and Wahren atlas of cryogenic slices. The volumetric atlas can be non-linearly deformed to an individual patient's MRI. To facilitate the clinical use of the atlas, a visualization platform has been developed for pre- and intra-operative use which permits manipulation of the merged atlas and MRI data sets in two- and three-dimensional views. The platform includes graphical tools which allow the visualization of projections of the leukotome and other surgical tools with respect to the atlas data, as well as pre- registered images from any other imaging modality. In addition, a graphical interface has been designed to create custom virtual lesions using computer models of neurosurgical tools for intra-operative planning. To date 17 clinical cases have been successfully performed using the described system.

Sex differences in brain activation elicited by humor.

PubMed

Azim, Eiman; Mobbs, Dean; Jo, Booil; Menon, Vinod; Reiss, Allan L

2005-11-08

With recent investigation beginning to reveal the cortical and subcortical neuroanatomical correlates of humor appreciation, the present event-related functional MRI (fMRI) study was designed to elucidate sex-specific recruitment of these humor related networks. Twenty healthy subjects (10 females) underwent fMRI scanning while subjectively rating 70 verbal and nonverbal achromatic cartoons as funny or unfunny. Data were analyzed by comparing blood oxygenation-level-dependent signal activation during funny and unfunny stimuli. Males and females share an extensive humor-response strategy as indicated by recruitment of similar brain regions: both activate the temporal-occipital junction and temporal pole, structures implicated in semantic knowledge and juxtaposition, and the inferior frontal gyrus, likely to be involved in language processing. Females, however, activate the left prefrontal cortex more than males, suggesting a greater degree of executive processing and language-based decoding. Females also exhibit greater activation of mesolimbic regions, including the nucleus accumbens, implying greater reward network response and possibly less reward expectation. These results indicate sex-specific differences in neural response to humor with implications for sex-based disparities in the integration of cognition and emotion.

Multiparametric imaging of brain hemodynamics and function using gas-inhalation MRI.

PubMed

Liu, Peiying; Welch, Babu G; Li, Yang; Gu, Hong; King, Darlene; Yang, Yihong; Pinho, Marco; Lu, Hanzhang

2017-02-01

Diagnosis and treatment monitoring of cerebrovascular diseases routinely require hemodynamic imaging of the brain. Current methods either only provide part of the desired information or require the injection of multiple exogenous agents. In this study, we developed a multiparametric imaging scheme for the imaging of brain hemodynamics and function using gas-inhalation MRI. The proposed technique uses a single MRI scan to provide simultaneous measurements of baseline venous cerebral blood volume (vCBV), cerebrovascular reactivity (CVR), bolus arrival time (BAT), and resting-state functional connectivity (fcMRI). This was achieved with a novel, concomitant O 2 and CO 2 gas inhalation paradigm, rapid MRI image acquisition with a 9.3min BOLD sequence, and an advanced algorithm to extract multiple hemodynamic information from the same dataset. In healthy subjects, CVR and vCBV values were 0.23±0.03%/mmHg and 0.0056±0.0006%/mmHg, respectively, with a strong correlation (r=0.96 for CVR and r=0.91 for vCBV) with more conventional, separate acquisitions that take twice the scan time. In patients with Moyamoya syndrome, CVR in the stenosis-affected flow territories (typically anterior-cerebral-artery, ACA, and middle-cerebral-artery, MCA, territories) was significantly lower than that in posterior-cerebral-artery (PCA), which typically has minimal stenosis, flow territories (0.12±0.06%/mmHg vs. 0.21±0.05%/mmHg, p<0.001). BAT of the gas bolus was significantly longer (p=0.008) in ACA/MCA territories, compared to PCA, and the maps were consistent with the conventional contrast-enhanced CT perfusion method. FcMRI networks were robustly identified from the gas-inhalation MRI data after factoring out the influence of CO 2 and O 2 on the signal time course. The spatial correspondence between the gas-data-derived fcMRI maps and those using a separate, conventional fcMRI scan was excellent, showing a spatial correlation of 0.58±0.17 and 0.64±0.20 for default mode network and primary visual network, respectively. These findings suggest that advanced gas-inhalation MRI provides reliable measurements of multiple hemodynamic parameters within a clinically acceptable imaging time and is suitable for patient examinations. Copyright © 2016 Elsevier Inc. All rights reserved.

Multiparametric imaging of brain hemodynamics and function using gas-inhalation MRI

PubMed Central

Liu, Peiying; Welch, Babu G.; Li, Yang; Gu, Hong; King, Darlene; Yang, Yihong; Pinho, Marco; Lu, Hanzhang

2016-01-01

Diagnosis and treatment monitoring of cerebrovascular diseases routinely require hemodynamic imaging of the brain. Current methods either only provide part of the desired information or require the injection of multiple exogenous agents. In this study, we developed a multiparametric imaging scheme for the imaging of brain hemodynamics and function using gas-inhalation MRI. The proposed technique uses a single MRI scan to provide simultaneous measurements of baseline venous cerebral blood volume (vCBV), cerebrovascular reactivity (CVR), bolus arrival time (BAT), and resting-state functional connectivity (fcMRI). This was achieved with a novel, concomitant O2 and CO2 gas inhalation paradigm, rapid MRI image acquisition with a 9.3 min BOLD sequence, and an advanced algorithm to extract multiple hemodynamic information from the same dataset. In healthy subjects, CVR and vCBV values were 0.23±0.03 %/mmHg and 0.0056±0.0006 %/mmHg, respectively, with a strong correlation (r=0.96 for CVR and r=0.91 for vCBV) with more conventional, separate acquisitions that take twice the scan time. In patients with Moyamoya syndrome, CVR in the stenosis-affected flow territories (typically anterior-cerebral-artery, ACA, and middle-cerebral-artery, MCA, territories) was significantly lower than that in posterior-cerebral-artery (PCA), which typically has minimal stenosis, flow territories (0.12±0.06 %/mmHg vs. 0.21±0.05 %/mmHg, p<0.001). BAT of the gas bolus was significantly longer (p=0.008) in ACA/MCA territories, compared to PCA, and the maps were consistent with the conventional contrast-enhanced CT perfusion method. FcMRI networks were robustly identified from the gas-inhalation MRI data after factoring out the influence of CO2 and O2 on the signal time course. The spatial correspondence between the gas-data-derived fcMRI maps and those using a separate, conventional fcMRI scan was excellent, showing a spatial correlation of 0.58±0.17 and 0.64±0.20 for default mode network and primary visual network, respectively. These findings suggest that advanced gas-inhalation MRI provides reliable measurements of multiple hemodynamic parameters within a clinically acceptable imaging time and is suitable for patient examinations. PMID:27693197