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Sample records for enhancement mri distinguishes

  1. Spatio-temporal texture (SpTeT) for distinguishing vulnerable from stable atherosclerotic plaque on dynamic contrast enhancement (DCE) MRI in a rabbit model

    PubMed Central

    Wan, Tao; Madabhushi, Anant; Phinikaridou, Alkystis; Hamilton, James A.; Hua, Ning; Pham, Tuan; Danagoulian, Jovanna; Kleiman, Ross; Buckler, Andrew J.

    2014-01-01

    Purpose: To develop a new spatio-temporal texture (SpTeT) based method for distinguishing vulnerable versus stable atherosclerotic plaques on DCE-MRI using a rabbit model of atherothrombosis. Methods: Aortic atherosclerosis was induced in 20 New Zealand White rabbits by cholesterol diet and endothelial denudation. MRI was performed before (pretrigger) and after (posttrigger) inducing plaque disruption with Russell's-viper-venom and histamine. Of the 30 vascular targets (segments) under histology analysis, 16 contained thrombus (vulnerable) and 14 did not (stable). A total of 352 voxel-wise computerized SpTeT features, including 192 Gabor, 36 Kirsch, 12 Sobel, 52 Haralick, and 60 first-order textural features, were extracted on DCE-MRI to capture subtle texture changes in the plaques over the course of contrast uptake. Different combinations of SpTeT feature sets, in which the features were ranked by a minimum-redundancy-maximum-relevance feature selection technique, were evaluated via a random forest classifier. A 500 iterative 2-fold cross validation was performed for discriminating the vulnerable atherosclerotic plaque and stable atherosclerotic plaque on per voxel basis. Four quantitative metrics were utilized to measure the classification results in separating between vulnerable and stable plaques. Results: The quantitative results show that the combination of five classes of SpTeT features can distinguish between vulnerable (disrupted plaques with an overlying thrombus) and stable plaques with the best AUC values of 0.9631 0.0088, accuracy of 89.98% 0.57%, sensitivity of 83.71% 1.71%, and specificity of 94.55% 0.48%. Conclusions: Vulnerable and stable plaque can be distinguished by SpTeT based features. The SpTeT features, following validation on larger datasets, could be established as effective and reliable imaging biomarkers for noninvasively assessing atherosclerotic risk. PMID:24694153

  2. Distinguishing grammatical constructions with fMRI pattern analysis.

    PubMed

    Allen, Kachina; Pereira, Francisco; Botvinick, Matthew; Goldberg, Adele E

    2012-12-01

    All linguistic and psycholinguistic theories aim to provide psychologically valid analyses of particular grammatical patterns and the relationships that hold among them. Until recently, no tools were available to distinguish neural correlates of particular grammatical constructions that shared the same content words, propositional meaning, and degree of surface complexity, such as the dative (e.g., Sally gave the book to Joe) and the ditransitive (e.g., Sally gave Joe a book). We report the first fMRI data that distinguish such closely related, abstract grammatical patterns. Multi-voxel pattern analysis (MVPA) proved capable of discriminating at above-chance levels between activity patterns arising during reading of dative and ditransitive sentences. Region-of-interest analyses reveal that the union of certain language-relevant areas, anterior and posterior BA22, BA44/45 and BA47, yield classification accuracy above chance and above that of control conditions in the left hemisphere but not in the right. Looking more closely at the LH ROIs, we find that the combination of areas aBA22 and BA47 is sufficient to distinguish the two constructions better than the controls and better than chance. The fact that both of these areas-particularly BA47-have been implicated in semantics, lends support to claims that the two constructions are distinguishable semantically. More generally, the ability to distinguish closely related grammatical constructions using MVPA offers the promise of addressing traditional theoretical questions on a neuroscientifically grounded basis. PMID:23010489

  3. On the distinguishability of HRF models in fMRI

    PubMed Central

    Rosa, Paulo N.; Figueiredo, Patricia; Silvestre, Carlos J.

    2015-01-01

    Modeling the Hemodynamic Response Function (HRF) is a critical step in fMRI studies of brain activity, and it is often desirable to estimate HRF parameters with physiological interpretability. A biophysically informed model of the HRF can be described by a non-linear time-invariant dynamic system. However, the identification of this dynamic system may leave much uncertainty on the exact values of the parameters. Moreover, the high noise levels in the data may hinder the model estimation task. In this context, the estimation of the HRF may be seen as a problem of model falsification or invalidation, where we are interested in distinguishing among a set of eligible models of dynamic systems. Here, we propose a systematic tool to determine the distinguishability among a set of physiologically plausible HRF models. The concept of absolutely input-distinguishable systems is introduced and applied to a biophysically informed HRF model, by exploiting the structure of the underlying non-linear dynamic system. A strategy to model uncertainty in the input time-delay and magnitude is developed and its impact on the distinguishability of two physiologically plausible HRF models is assessed, in terms of the maximum noise amplitude above which it is not possible to guarantee the falsification of one model in relation to another. Finally, a methodology is proposed for the choice of the input sequence, or experimental paradigm, that maximizes the distinguishability of the HRF models under investigation. The proposed approach may be used to evaluate the performance of HRF model estimation techniques from fMRI data. PMID:26106322

  4. Distinguishing prostate cancer from benign confounders via a cascaded classifier on multi-parametric MRI

    NASA Astrophysics Data System (ADS)

    Litjens, G. J. S.; Elliott, R.; Shih, N.; Feldman, M.; Barentsz, J. O.; Hulsbergen-van de Kaa, C. A.; Kovacs, I.; Huisman, H. J.; Madabhushi, A.

    2014-03-01

    Learning how to separate benign confounders from prostate cancer is important because the imaging characteristics of these confounders are poorly understood. Furthermore, the typical representations of the MRI parameters might not be enough to allow discrimination. The diagnostic uncertainty this causes leads to a lower diagnostic accuracy. In this paper a new cascaded classifier is introduced to separate prostate cancer and benign confounders on MRI in conjunction with specific computer-extracted features to distinguish each of the benign classes (benign prostatic hyperplasia (BPH), inflammation, atrophy or prostatic intra-epithelial neoplasia (PIN). In this study we tried to (1) calculate different mathematical representations of the MRI parameters which more clearly express subtle differences between different classes, (2) learn which of the MRI image features will allow to distinguish specific benign confounders from prostate cancer, and (2) find the combination of computer-extracted MRI features to best discriminate cancer from the confounding classes using a cascaded classifier. One of the most important requirements for identifying MRI signatures for adenocarcinoma, BPH, atrophy, inflammation, and PIN is accurate mapping of the location and spatial extent of the confounder and cancer categories from ex vivo histopathology to MRI. Towards this end we employed an annotated prostatectomy data set of 31 patients, all of whom underwent a multi-parametric 3 Tesla MRI prior to radical prostatectomy. The prostatectomy slides were carefully co-registered to the corresponding MRI slices using an elastic registration technique. We extracted texture features from the T2-weighted imaging, pharmacokinetic features from the dynamic contrast enhanced imaging and diffusion features from the diffusion-weighted imaging for each of the confounder classes and prostate cancer. These features were selected because they form the mainstay of clinical diagnosis. Relevant features for each of the classes were selected using maximum relevance minimum redundancy feature selection, allowing us to perform classifier independent feature selection. The selected features were then incorporated in a cascading classifier, which can focus on easier sub-tasks at each stage, leaving the more difficult classification tasks for later stages. Results show that distinct features are relevant for each of the benign classes, for example the fraction of extra-vascular, extra-cellular space in a voxel is a clear discriminator for inflammation. Furthermore, the cascaded classifier outperforms both multi-class and one-shot classifiers in overall accuracy for discriminating confounders from cancer: 0.76 versus 0.71 and 0.62.

  5. Distinguishing Grammatical Constructions with fMRI Pattern Analysis

    ERIC Educational Resources Information Center

    Allen, Kachina; Pereira, Francisco; Botvinick, Matthew; Goldberg, Adele E.

    2012-01-01

    All linguistic and psycholinguistic theories aim to provide psychologically valid analyses of particular grammatical patterns and the relationships that hold among them. Until recently, no tools were available to distinguish neural correlates of particular grammatical constructions that shared the same content words, propositional meaning, and

  6. Texture Descriptors to distinguish Radiation Necrosis from Recurrent Brain Tumors on multi-parametric MRI.

    PubMed

    Pallavi, Tiwari; Prateek, Prasanna; Lisa, Rogers; Leo, Wolansky; Chaitra, Badve; Andrew, Sloan; Mark, Cohen; Anant, Madabhushi

    2014-01-01

    Differentiating radiation necrosis (a radiation induced treatment effect) from recurrent brain tumors (rBT) is currently one of the most clinically challenging problems in care and management of brain tumor (BT) patients. Both radiation necrosis (RN), and rBT exhibit similar morphological appearance on standard MRI making non-invasive diagnosis extremely challenging for clinicians, with surgical intervention being the only course for obtaining definitive "ground truth". Recent studies have reported that the underlying biological pathways defining RN and rBT are fundamentally different. This strongly suggests that there might be phenotypic differences and hence cues on multi-parametric MRI, that can distinguish between the two pathologies. One challenge is that these differences, if they exist, might be too subtle to distinguish by the human observer. In this work, we explore the utility of computer extracted texture descriptors on multi-parametric MRI (MP-MRI) to provide alternate representations of MRI that may be capable of accentuating subtle micro-architectural differences between RN and rBT for primary and metastatic (MET) BT patients. We further explore the utility of texture descriptors in identifying the MRI protocol (from amongst T1-w, T2-w and FLAIR) that best distinguishes RN and rBT across two independent cohorts of primary and MET patients. A set of 119 texture descriptors (co-occurrence matrix homogeneity, neighboring gray-level dependence matrix, multi-scale Gaussian derivatives, Law features, and histogram of gradient orientations (HoG)) for modeling different macro and micro-scale morphologic changes within the treated lesion area for each MRI protocol were extracted. Principal component analysis based variable importance projection (PCA-VIP), a feature selection method previously developed in our group, was employed to identify the importance of every texture descriptor in distinguishing RN and rBT on MP-MRI. PCA-VIP employs regression analysis to provide an importance score to each feature based on their ability to distinguish the two classes (RN/rBT). The top performing features identified via PCA-VIP were employed within a random-forest classifier to differentiate RN from rBT across two cohorts of 20 primary and 22 MET patients. Our results revealed that, (a) HoG features at different orientations were the most important image features for both cohorts, suggesting inherent orientation differences between RN, and rBT, (b) inverse difference moment (capturing local intensity homogeneity), and Laws features (capturing local edges and gradients) were identified as important for both cohorts, and (c) Gd-C T1-w MRI was identified, across the two cohorts, as the best MRI protocol in distinguishing RN/rBT. PMID:24910722

  7. Texture descriptors to distinguish radiation necrosis from recurrent brain tumors on multi-parametric MRI

    NASA Astrophysics Data System (ADS)

    Tiwari, Pallavi; Prasanna, Prateek; Rogers, Lisa; Wolansky, Leo; Badve, Chaitra; Sloan, Andrew; Cohen, Mark; Madabhushi, Anant

    2014-03-01

    Di erentiating radiation necrosis (a radiation induced treatment e ect) from recurrent brain tumors (rBT) is currently one of the most clinically challenging problems in care and management of brain tumor (BT) patients. Both radiation necrosis (RN), and rBT exhibit similar morphological appearance on standard MRI making non-invasive diagnosis extremely challenging for clinicians, with surgical intervention being the only course for obtaining de nitive ground truth". Recent studies have reported that the underlying biological pathways de n- ing RN and rBT are fundamentally di erent. This strongly suggests that there might be phenotypic di erences and hence cues on multi-parametric MRI, that can distinguish between the two pathologies. One challenge is that these di erences, if they exist, might be too subtle to distinguish by the human observer. In this work, we explore the utility of computer extracted texture descriptors on multi-parametric MRI (MP-MRI) to provide alternate representations of MRI that may be capable of accentuating subtle micro-architectural di erences between RN and rBT for primary and metastatic (MET) BT patients. We further explore the utility of texture descriptors in identifying the MRI protocol (from amongst T1-w, T2-w and FLAIR) that best distinguishes RN and rBT across two independent cohorts of primary and MET patients. A set of 119 texture descriptors (co-occurrence matrix homogeneity, neighboring gray-level dependence matrix, multi-scale Gaussian derivatives, Law features, and histogram of gradient orientations (HoG)) for modeling di erent macro and micro-scale morphologic changes within the treated lesion area for each MRI protocol were extracted. Principal component analysis based variable importance projection (PCA-VIP), a feature selection method previously developed in our group, was employed to identify the importance of every texture descriptor in distinguishing RN and rBT on MP-MRI. PCA-VIP employs regression analysis to provide an importance score to each feature based on their ability to distinguish the two classes (RN/rBT). The top performing features identi ed via PCA-VIP were employed within a random- forest classi er to di erentiate RN from rBT across two cohorts of 20 primary and 22 MET patients. Our results revealed that, (a) HoG features at di erent orientations were the most important image features for both cohorts, suggesting inherent orientation di erences between RN, and rBT, (b) inverse di erence moment (capturing local intensity homogeneity), and Laws features (capturing local edges and gradients) were identi ed as important for both cohorts, and (c) Gd-C T1-w MRI was identi ed, across the two cohorts, as the best MRI protocol in distinguishing RN/rBT.

  8. Distinguishing benign confounding treatment changes from residual prostate cancer on MRI following laser ablation

    NASA Astrophysics Data System (ADS)

    Litjens, G.; Huisman, H.; Elliott, R.; Shih, N.; Feldman, M.; Viswanath, S.; Fütterer, J.; Bomers, J.; Madabhushi, A.

    2014-03-01

    Laser interstitial thermotherapy (LITT) is a relatively new focal therapy technique for the ablation of localized prostate cancer. However, very little is known about the specific effects of LITT within the ablation zone and the surrounding normal tissue regions. For instance, it is important to be able to assess the extent of residual cancer within the prostate following LITT, which may be masked by thermally induced benign necrotic changes. Fortunately LITT is MRI compatible and hence this allows for quantitatively assessing LITT induced changes via multi-parametric MRI. Of course definite validation of any LITT induced changes on MRI requires confirmation via histopathology. The aim of this study was to quantitatively assess and distinguish the imaging characteristics of prostate cancer and benign confounding treatment changes following LITTon 3 Tesla multi-parametric MRI by carefully mapping the treatment related changes from the ex vivo surgically resected histopathologic specimens onto the pre-operative in vivo imaging. A better understanding of the imaging characteristics of residual disease and successfully ablated tissue might lead to improved treatment monitoring and as such patient prognosis. A unique clinical trial at the Radboud University Medical Center, in which 3 patients underwent a prostatectomy after LITT treatment, yielded ex-vivo histopathologic specimens along with pre- and post-LITT MRI. Using this data we (1) identified the computer extracted MRI signatures associated with treatment effects including benign necrotic changes and residual disease and (2) subsequently evaluated the computer extracted MRI features previously identified in distinguishing LITT induced changes in the ablated area relative to the residual disease. Towards this end first a pathologist annotated the ablated area and the residual disease on the ex-vivo histology and then we transferred the annotations to the post-LITT MRI using semi-automatic elastic registration. The pre- and post-LITT MRI were subsequently registered and computer-derived multi-parametric MRI features extracted to determine differences in feature values between residual disease and successfully ablated tissue to assess treatment response. A scoring metric allowed us to identify those specific computer-extracted MRI features that maximally and differentially expressed between the ablated regions and the residual cancer, on a voxel- by­ voxel basis. Finally, we used a Fuzzy C-Means algorithm to assess the discriminatory power of these selected features. Our results show that specific computer-extracted features from multi-parametric MRI differentially express within the ablated and residual cancer regions, as evidenced by our ability to, on a voxel-by-voxel basis, classify tissue as residual disease. Additionally, we show that change of feature values between pre- and post­-LITT MRI may be useful as a quantitative marker for treatment response (T2-weighted texture and DCE MRI features showed largest differences between residual disease and successfully ablated tissue). Finally, a clustering approach to separate treatment effects and residual disease incorporating both (1) and (2) yielded a maximum area under the ROC curve of 0.97 on a voxel basis across 3 studies.

  9. Distinguishing Cancerous Liver Cells Using Surface-Enhanced Raman Spectroscopy.

    PubMed

    Huang, Jing; Liu, Shupeng; Chen, Zhenyi; Chen, Na; Pang, Fufei; Wang, Tingyun

    2016-02-01

    Raman spectroscopy has been widely used in biomedical research and clinical diagnostics. It possesses great potential for the analysis of biochemical processes in cell studies. In this article, the surface-enhanced Raman spectroscopy (SERS) of normal and cancerous liver cells incubated with SERS active substrates (gold nanoparticle) was measured using confocal Raman microspectroscopy technology. The chemical components of the cells were analyzed through statistical methods for the SERS spectrum. Both the relative intensity ratio and principal component analysis (PCA) were used for distinguishing the normal liver cells (QSG-7701) from the hepatoma cells (SMMC-7721). The relative intensity ratio of the Raman spectra peaks such as I937/I1209, I1276/I1308, I1342/I1375, and I1402/I1435 was set as the judge boundary, and the sensitivity and the specificity using PCA method were calculated. The results indicated that the surface-enhanced Raman spectrum could provide the chemical information for distinguishing the normal cells from the cancerous liver cells and demonstrated that SERS technology possessed the possible applied potential for the diagnosis of liver cancer. PMID:25432931

  10. Central nervous system infectious diseases mimicking multiple sclerosis: recognizing distinguishable features using MRI.

    PubMed

    Rocha, Antônio José da; Littig, Ingrid Aguiar; Nunes, Renato Hoffmann; Tilbery, Charles Peter

    2013-09-01

    The current diagnostic criteria for multiple sclerosis (MS) confirm the relevant role of magnetic resonance imaging (MRI), supporting the possibility of characterizing the dissemination in space (DIS) and the dissemination in time (DIT) in a single scan. To maintain the specificity of these criteria, it is necessary to determine whether T2/FLAIR visible lesions and the gadolinium enhancement can be attributed to diseases that mimic MS. Several diseases are included in the MS differential diagnosis list, including diseases with exacerbation, remitting periods and numerous treatable infectious diseases, which can mimic the MRI features of MS. We discuss the most relevant imaging features in several infectious diseases that resemble MS and examine the primary spatial distributions of lesions and the gadolinium enhancement patterns related to MS. Recognizing imaging "red flags" can be useful for the proper diagnostic evaluation of suspected cases of MS, facilitating the correct differential diagnosis by assessing the combined clinical, laboratory and MR imaging information. PMID:24141516

  11. MRI contrast enhancement using Magnetic Carbon Nanoparticles

    NASA Astrophysics Data System (ADS)

    Chaudhary, Rakesh P.; Kangasniemi, Kim; Takahashi, Masaya; Mohanty, Samarendra K.; Koymen, Ali R.; Department of Physics, University of Texas at Arlington Team; University of Texas Southwestern Medical Center Team

    2014-03-01

    In recent years, nanotechnology has become one of the most exciting forefront fields in cancer diagnosis and therapeutics such as drug delivery, thermal therapy and detection of cancer. Here, we report development of core (Fe)-shell (carbon) nanoparticles with enhanced magnetic properties for contrast enhancement in MRI imaging. These new classes of magnetic carbon nanoparticles (MCNPs) are synthesized using a bottom-up approach in various organic solvents, using the electric plasma discharge generated in the cavitation field of an ultrasonic horn. Gradient echo MRI images of well-dispersed MCNP-solutions (in tube) were acquired. For T2 measurements, a multi echo spin echo sequence was performed. From the slope of the 1/T2 versus concentration plot, the R2 value for different CMCNP-samples was measured. Since MCNPs were found to be extremely non-reactive, and highly absorbing in NIR regime, development of carbon-based MRI contrast enhancement will allow its simultaneous use in biomedical applications. We aim to localize the MCNPs in targeted tissue regions by external DC magnetic field, followed by MRI imaging and subsequent photothermal therapy.

  12. A robust classifier to distinguish noise from fMRI independent components.

    PubMed

    Sochat, Vanessa; Supekar, Kaustubh; Bustillo, Juan; Calhoun, Vince; Turner, Jessica A; Rubin, Daniel L

    2014-01-01

    Analyzing Functional Magnetic Resonance Imaging (fMRI) of resting brains to determine the spatial location and activity of intrinsic brain networks--a novel and burgeoning research field--is limited by the lack of ground truth and the tendency of analyses to overfit the data. Independent Component Analysis (ICA) is commonly used to separate the data into signal and Gaussian noise components, and then map these components on to spatial networks. Identifying noise from this data, however, is a tedious process that has proven hard to automate, particularly when data from different institutions, subjects, and scanners is used. Here we present an automated method to delineate noisy independent components in ICA using a data-driven infrastructure that queries a database of 246 spatial and temporal features to discover a computational signature of different types of noise. We evaluated the performance of our method to detect noisy components from healthy control fMRI (sensitivity?=?0.91, specificity?=?0.82, cross validation accuracy (CVA)?=?0.87, area under the curve (AUC)?=?0.93), and demonstrate its generalizability by showing equivalent performance on (1) an age- and scanner-matched cohort of schizophrenia patients from the same institution (sensitivity?=?0.89, specificity?=?0.83, CVA?=?0.86), (2) an age-matched cohort on an equivalent scanner from a different institution (sensitivity?=?0.88, specificity?=?0.88, CVA?=?0.88), and (3) an age-matched cohort on a different scanner from a different institution (sensitivity?=?0.72, specificity?=?0.92, CVA?=?0.79). We additionally compare our approach with a recently published method. Our results suggest that our method is robust to noise variations due to population as well as scanner differences, thereby making it well suited to the goal of automatically distinguishing noise from functional networks to enable investigation of human brain function. PMID:24748378

  13. Distinguishing the Processing of Gestures from Signs in Deaf Individuals: An fMRI Study

    PubMed Central

    Husain, Fatima T.; Patkin, Debra J.; Thai-Van, Hung; Braun, Allen R.; Horwitz, Barry

    2009-01-01

    Manual gestures occur on a continuum from co-speech gesticulations to conventionalized emblems to language signs. Our goal in the present study was to understand the neural bases of the processing of gestures along such a continuum. We studied four types of gestures, varying along linguistic and semantic dimensions: linguistic and meaningful American Sign Language (ASL), non-meaningful pseudo-ASL, meaningful emblematic, and nonlinguistic, non-meaningful made-up gestures. Pre-lingually deaf, native signers of ASL participated in the fMRI study and performed two tasks while viewing videos of the gestures: a visuo-spatial (identity) discrimination task and a category discrimination task. We found that the categorization task activated left ventral middle and inferior frontal gyrus, among other regions, to a greater extent compared to the visual discrimination task, supporting the idea of semantic-level processing of the gestures. The reverse contrast resulted in enhanced activity of bilateral intraparietal sulcus, supporting the idea of featural-level processing (analogous to phonological-level processing of speech sounds) of the gestures. Regardless of the task, we found that brain activation patterns for the nonlinguistic, non-meaningful gestures were the most different compared to the ASL gestures. The activation patterns for the emblems were most similar to those of the ASL gestures and those of the pseudo-ASL were most similar to the nonlinguistic, non-meaningful gestures. The fMRI results provide partial support for the conceptualization of different gestures as belonging to a continuum and the variance in the fMRI results was best explained by differences in the processing of gestures along the semantic dimension. PMID:19397900

  14. A Robust Classifier to Distinguish Noise from fMRI Independent Components

    PubMed Central

    Sochat, Vanessa; Supekar, Kaustubh; Bustillo, Juan; Calhoun, Vince; Turner, Jessica A.; Rubin, Daniel L.

    2014-01-01

    Analyzing Functional Magnetic Resonance Imaging (fMRI) of resting brains to determine the spatial location and activity of intrinsic brain networks–a novel and burgeoning research field–is limited by the lack of ground truth and the tendency of analyses to overfit the data. Independent Component Analysis (ICA) is commonly used to separate the data into signal and Gaussian noise components, and then map these components on to spatial networks. Identifying noise from this data, however, is a tedious process that has proven hard to automate, particularly when data from different institutions, subjects, and scanners is used. Here we present an automated method to delineate noisy independent components in ICA using a data-driven infrastructure that queries a database of 246 spatial and temporal features to discover a computational signature of different types of noise. We evaluated the performance of our method to detect noisy components from healthy control fMRI (sensitivity = 0.91, specificity = 0.82, cross validation accuracy (CVA) = 0.87, area under the curve (AUC) = 0.93), and demonstrate its generalizability by showing equivalent performance on (1) an age- and scanner-matched cohort of schizophrenia patients from the same institution (sensitivity = 0.89, specificity = 0.83, CVA = 0.86), (2) an age-matched cohort on an equivalent scanner from a different institution (sensitivity = 0.88, specificity = 0.88, CVA = 0.88), and (3) an age-matched cohort on a different scanner from a different institution (sensitivity = 0.72, specificity = 0.92, CVA = 0.79). We additionally compare our approach with a recently published method [1]. Our results suggest that our method is robust to noise variations due to population as well as scanner differences, thereby making it well suited to the goal of automatically distinguishing noise from functional networks to enable investigation of human brain function. PMID:24748378

  15. Can Asperger syndrome be distinguished from autism? An anatomic likelihood meta-analysis of MRI studies

    PubMed Central

    Yu, Kevin K.; Cheung, Charlton; Chua, Siew E.; McAlonan, Grinne M.

    2011-01-01

    Background The question of whether Asperger syndrome can be distinguished from autism has attracted much debate and may even incur delay in diagnosis and intervention. Accordingly, there has been a proposal for Asperger syndrome to be subsumed under autism in the forthcoming Diagnostic and Statistical Manual of Mental Disorders, fifth edition, in 2013. One approach to resolve this question has been to adopt the criterion of absence of clinically significant language or cognitive delay essentially, the absence of language delay. To our knowledge, this is the first meta-analysis of magnetic resonance imaging (MRI) studies of people with autism to compare absence with presence of language delay. It capitalizes on the voxel-based morphometry (VBM) approach to systematically explore the whole brain for anatomic correlates of delay and no delay in language acquisition in people with autism spectrum disorders. Methods We conducted a systematic search for VBM MRI studies of grey matter volume in people with autism. Studies with a majority (at least 70%) of participants with autism diagnoses and a history of language delay were assigned to the autism group (n = 151, control n = 190). Those with a majority (at least 70%) of individuals with autism diagnoses and no language delay were assigned to the Asperger syndrome group (n = 149, control n = 214). We entered study coordinates into anatomic likelihood estimation meta-analysis software with sampling size weighting to compare grey matter summary maps driven by Asperger syndrome or autism. Results The summary autism grey matter map showed lower volumes in the cerebellum, right uncus, dorsal hippocampus and middle temporal gyrus compared with controls; grey matter volumes were greater in the bilateral caudate, prefrontal lobe and ventral temporal lobe. The summary Asperger syndrome map indicated lower grey matter volumes in the bilateral amygdala/hippocampal gyrus and prefrontal lobe, left occipital gyrus, right cerebellum, putamen and precuneus compared with controls; grey matter volumes were greater in more limited regions, including the bilateral inferior parietal lobule and the left fusiform gyrus. Both Asperger syndrome and autism studies reported volume increase in clusters in the ventral temporal lobe of the left hemisphere. Limitations We assigned studies to autism and Asperger syndrome groups for separate analyses of the data and did not carry out a direct statistical group comparison. In addition, studies available for analysis did not capture the entire spectrum, therefore we cannot be certain that our findings apply to a wider population than that sampled. Conclusion Whereas grey matter differences in people with Asperger syndrome compared with controls are sparser than those reported in studies of people with autism, the distribution and direction of differences in each category are distinctive. PMID:21406158

  16. MRI RESOLUTION ENHANCEMENT USING TOTAL VARIATION REGULARIZATION

    PubMed Central

    Joshi, Shantanu H.; Marquina, Antonio; Osher, Stanley J.; Dinov, Ivo; Van Horn, John D.; Toga, Arthur W.

    2010-01-01

    We propose a novel method for resolution enhancement for volumetric images based on a variational-based reconstruction approach. The reconstruction problem is posed using a deconvolution model that seeks to minimize the total variation norm of the image. Additionally, we propose a new edge-preserving operator that emphasizes and even enhances edges during the up-sampling and decimation of the image. The edge enhanced reconstruction is shown to yield significant improvement in resolution, especially preserving important edges containing anatomical information. This method is demonstrated as an enhancement tool for low-resolution, anisotropic, 3D brain MRI images, as well as a pre-processing step to improve skull-stripping segmentation of brain images. PMID:21113426

  17. USPIO-Enhanced MRI Neuroimaging: A Review.

    PubMed

    Gkagkanasiou, Maria; Ploussi, Agapi; Gazouli, Maria; Efstathopoulos, Efstathios P

    2016-03-01

    MRI is a powerful tool for the diagnosis and management for a variety of central nervous system (CNS) diseases. Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are a novel category of MRI contrast agents that seem to play a crucial role in the imaging of CNS. Due to their physical properties, USPIOs act as blood pool agents. USPIOs improve visualization of tumor vasculature and relative cerebral blood volume measurements, tumor-associated inflammation, inflammatory-immune mediated disorders, stroke and vascular malformations. Ferumoxytol, a new type of USPIO agent, appears to have ideal characteristics for the imaging of CNS. The last few years, ferumoxytol has been successfully used to image CNS neoplasms, CNS inflammations and cerebral malformations offering useful information on cellular and molecular level. In addition, ferumoxytol studies focused on the pathophysiology of other CNS disorders like multiple sclerosis and epilepsy are already in progress. Aim of this review article is to provide the potential role of USPIO-enhanced MRI and the latest clinical applications of ferumoxytol agent in CNS imaging. PMID:26932522

  18. Fundamentals of tracer kinetics for dynamic contrast-enhanced MRI.

    PubMed

    Koh, Tong San; Bisdas, Sotirios; Koh, Dow Mu; Thng, Choon Hua

    2011-12-01

    Tracer kinetic methods employed for quantitative analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) share common roots with earlier tracer studies involving arterial-venous sampling and other dynamic imaging modalities. This article reviews the essential foundation concepts and principles in tracer kinetics that are relevant to DCE MRI, including the notions of impulse response and convolution, which are central to the analysis of DCE MRI data. We further examine the formulation and solutions of various compartmental models frequently used in the literature. Topics of recent interest in the processing of DCE MRI data, such as the account of water exchange and the use of reference tissue methods to obviate the measurement of an arterial input, are also discussed. Although the primary focus of this review is on the tracer models and methods for T(1) -weighted DCE MRI, some of these concepts and methods are also applicable for analysis of dynamic susceptibility contrast-enhanced MRI data. PMID:21972053

  19. Gadolinium enhanced MRI predicts clinical and MRI disease activity in relapsing-remitting multiple sclerosis.

    PubMed

    Koudriavtseva, T; Thompson, A J; Fiorelli, M; Gasperini, C; Bastianello, S; Bozzao, A; Paolillo, A; Pisani, A; Galgani, S; Pozzilli, C

    1997-03-01

    The aim of the study was to evaluate the predictive power of baseline gadolinium (Gd) enhanced MRI in relation to subsequent clinical and MRI activity. Sixty eight patients with clinically definite relapsing-remitting multiple sclerosis had a baseline Gd enhanced MRI and were followed up clinically and by monthly Gd enhanced MRI for six months. The occurrence of relapses during the follow up period was predicted by the presence of at least one enhancing lesion on the baseline MRI (P < 0.05). The number and volume of enhancing lesions at baseline were significantly associated with both enhancing lesions observed during the follow up period (P < 0.0001) and the accumulation of abnormality on T2 weighted images (P < 0.0001). Moreover, the presence of three or more enhancing lesions at baseline scan was consistently associated with the development of permanent abnormalities on T2 weighted images six months later. The study suggests that the number and volume of Gd enhancing lesions at a single examination are strong short term predictors of subsequent clinical and MRI activity. PMID:9069488

  20. Dynamic Contrast-Enhanced MRI--Meeting Report

    Cancer.gov

    A. Rationale for the Workshop In the last several years contrast-enhanced MR angiography (CE-MRA) has become a commonly used, commercially available method. In parallel with this, dynamic contrast-enhanced MR imaging (DCE-MRI) has emerged as a promising method for diagnosis and prognosis of cancer. However, widespread use of DCE-MRI is limited by the need for further technical improvements.

  1. Assessment of ameloblastomas using MRI and dynamic contrast-enhanced MRI.

    PubMed

    Asaumi, Jun-ichi; Hisatomi, Miki; Yanagi, Yoshinobu; Matsuzaki, Hidenobu; Choi, Yong Suk; Kawai, Noriko; Konouchi, Hironobu; Kishi, Kanji

    2005-10-01

    We retrospectively evaluated magnetic resonance images (MRI) and dynamic contrast-enhanced MRI (DCE-MRI) of ameloblastomas. MRI and DCE-MRI were performed for 10 ameloblastomas. We obtained the following results from the MRI and DCE-MRI. (a) Ameloblastomas can be divided into solid and cystic portions on the basis of MR signal intensities. (b) Ameloblastomas show a predilection for intermediate signal intensity on T1WI, high signal intensity on T2WI, and well enhancement in the solid portion; they also show a homogeneous intermediate signal intensity on T1WI and homogeneous high signal intensity on T2WI, and no enhancement in the cystic portion. (c) The mural nodule or thick wall can be detected in ameloblastomas lesions. (d) CI curves of ameloblastomas show two patterns: the first pattern increases, reaches a plateau at 100-300 s, then sustains the plateau or decreases gradually to 600-900 s, while the other increases relatively rapidly, reaches a plateau at 90-120 s, then decreases relatively rapidly to 300 s, and decreases gradually thereafter. There was no difference in the CI curve patterns among primary and recurrent cases, a case with glandular odontogenic tumor in ameloblastoma or among histopathological types such as plexiform, follicular, mixed, desmoplastic, and unicystic type. PMID:16168260

  2. Comparison between Breast MRI and Contrast-Enhanced Spectral Mammography

    PubMed Central

    ?uczy?ska, El?bieta; Heinze-Paluchowska, Sylwia; Hendrick, Edward; Dyczek, Sonia; Ry?, Janusz; Herman, Krzysztof; Blecharz, Pawe?; Jakubowicz, Jerzy

    2015-01-01

    Background The main goal of this study was to compare contrast-enhanced spectral mammography (CESM) and breast magnetic resonance imaging (MRI) with histopathological results and to compare the sensitivity, accuracy, and positive and negative predictive values for both imaging modalities. Material/Methods After ethics approval, CESM and MRI examinations were performed in 102 patients who had suspicious lesions described in conventional mammography. All visible lesions were evaluated independently by 2 experienced radiologists using BI-RADS classifications (scale 15). Dimensions of lesions measured with each modality were compared to postoperative histopathology results. Results There were 102 patients entered into CESM/MRI studies and 118 lesions were identified by the combination of CESM and breast MRI. Histopathology confirmed that 81 of 118 lesions were malignant and 37 were benign. Of the 81 malignant lesions, 72 were invasive cancers and 9 were in situ cancers. Sensitivity was 100% with CESM and 93% with breast MRI. Accuracy was 79% with CESM and 73% with breast MRI. ROC curve areas based on BI-RADS were 0.83 for CESM and 0.84 for breast MRI. Lesion size estimates on CESM and breast MRI were similar, both slightly larger than those from histopathology. Conclusions Our results indicate that CESM has the potential to be a valuable diagnostic method that enables accurate detection of malignant breast lesions, has high negative predictive value, and a false-positive rate similar to that of breast MRI. PMID:25963880

  3. Brain Parenchymal Fraction: A Relatively Simple MRI Measure to Clinically Distinguish ALS Phenotypes

    PubMed Central

    Rajagopalan, Venkateswaran; Pioro, Erik P.

    2015-01-01

    Even though neuroimaging and clinical studies indicate that amyotrophic lateral sclerosis (ALS) manifests with distinct clinical phenotypes, no objective test exists to assess upper motor degeneration in ALS. There is great interest in identifying biomarkers of ALS to allow earlier diagnosis and to recognize disease subtypes. Current quantitative neuroimaging techniques such as T2 relaxometry and diffusion tensor imaging are time-consuming to use in clinical settings due to extensive postprocessing requirements. Therefore, we aimed to study the potential role of brain parenchymal fraction (BPF) as a relatively simple quantitative measure for distinguishing ALS phenotypes. T1-weighted MR images of brain were obtained in 15 neurological controls and 88 ALS patients categorized into 4 distinct clinical phenotypes, upper motor neuron- (UMN-) predominant ALS patients with/without corticospinal tract (CST) hyperintensity on T2/PD-weighted images, classic ALS, and ALS with frontotemporal dementia (ALS-FTD). BPF was calculated using intracranial grey matter, white matter, and cerebrospinal fluid volumes obtained in control and ALS subgroups using SPM8 software. Only ALS-FTD patients had significant reduction in BPF when compared to controls and nondemented ALS patients. Correlation of clinical measures such as disease duration with BPF further supports the view that the BPF could be a potential biomarker for clinical diagnosis of ALS-FTD patients. PMID:26783524

  4. Contrast Enhanced MRI in the Diagnosis of HCC

    PubMed Central

    Niendorf, Eric; Spilseth, Benjamin; Wang, Xiao; Taylor, Andrew

    2015-01-01

    Hepatocellular carcinoma (HCC) is the 6th most common cancer worldwide. Imaging plays a critical role in HCC screening and diagnosis. Initial screening of patients at risk for HCC is performed with ultrasound. Confirmation of HCC can then be obtained by Computed Tomography (CT) or Magnetic Resonance Imaging (MRI), due to the relatively high specificity of both techniques. This article will focus on reviewing MRI techniques for imaging HCC, felt by many to be the exam of choice for HCC diagnosis. MRI relies heavily upon the use of gadolinium-based contrast agents and while primarily extracellular gadolinium-based contrast agents are used, there is an emerging role of hepatobiliary contrast agents in HCC imaging. The use of other non-contrast enhanced MRI techniques for assessing HCC will also be discussed and these MRI strategies will be reviewed in the context of the pathophysiology of HCC to help understand the MR imaging appearance of HCC.

  5. Differentiation of Reactive and Tumor Metastatic Lymph Nodes with Diffusion-weighted and SPIO Enhanced MRI

    PubMed Central

    Zhang, Fan; Zhu, Lei; Huang, Xinglu; Niu, Gang; Chen, Siouan

    2012-01-01

    Objectives Determination of lymphatic metastasis is of great importance for both treatment planning and patient prognosis. We aim to distinguish tumor metastatic lymph nodes (TLNs) and reactive lymph nodes (RLNs) with diffusion-weighted and superparamagnetic iron oxide (SPIO) enhanced magnetic resonance imaging (MRI). Materials and methods Ipsilateral popliteal lymph node metastasis or lymphadenitis model was established by hock injection of either luciferase-expressing 4T1 murine breast cancer cells or Complete Freund Adjuvant (CFA) in male Balb/C mice. At different time points after inoculation, bioluminescence imaging, T2-weighted, diffusion-weighted and SPIO enhanced MRI were performed. Imaging findings were confirmed by histopathological staining. Results Size enlargement was observed in both TLNs and RLNs. At day 28, TLNs showed strong bioluminescence signal and bigger size than RLNs (p < 0.01). At early stages up to day 21, both TLNs and RLNs appeared homogeneous on diffusion-weighted imaging (DWI). At day 28, TLNs showed heterogeneous apparent diffusion coefficient (ADC) map with significantly higher average ADC value of 0.41 ± 0.03 × 10−3 mm2/s than that of RLNs (0.34 ± 0.02 10−3 mm2/s, p < 0.05). On SPIO enhanced MRI, both TLNs and RLNs showed distinct T2 signal reduction at day 21 after inoculation. At day 28, TLNs demonstrated partial uptake of the iron oxide particles, which was confirmed by Prussian blue staining. Conclusions Both diffusion-weighted and SPIO enhanced MRI can distinguish tumor metastatic lymph nodes from reactive lymph nodes. However, neither method is able to detect tumor metastasis to the draining lymph nodes at early stages. PMID:22588595

  6. Clustered breast microcalcifications: Evaluation by dynamic contrast-enhanced subtraction MRI

    SciTech Connect

    Gilles, R.; Tardivon, A.A.; Vanel, D.; Guinebretiere, J.M.; Arriagada, R.

    1996-01-01

    Our goal was to evaluate dynamic contrast-enhanced subtraction MRI in the diagnosis of isolated clustered calcifications of the breast. One hundred seventy-two patients underwent surgical biopsy for isolated clustered breast calcifications. Their mammograms showed round (n = 88) or linear/irregular (n = 84) microcalcifications. All patients had a preoperative Gd-DOTA-enhanced subtraction dynamic study. Any early contrast enhancement in the breast parenchyma concomitant with early enhancement of normal vessels was considered positive. Fifty-eight in situ carcinomas, 22 invasive carcinomas, and 92 benign lesions were found at histological analysis. Dynamic MR sequences showed early contrast enhancement in 76 of 80 malignant lesions (sensitivity 95%) and in 45 of 92 benign lesions (specificity 51%). Two invasive and two intraductal carcinomas did not show early contrast enhancement. Three independent observers agreed in rating early contrast enhancement in 143 of 172 lesions. Poor specificity limits the diagnostic accuracy of dynamic contrast-enhanced subtraction MRI in distinguishing benign from malignant microcalcifications on mammography. 8 refs., 2 figs., 2 tabs.

  7. Manganese-Enhanced MRI: Biological Applications in Neuroscience.

    PubMed

    Malheiros, Jackeline Moraes; Paiva, Fernando Fernandes; Longo, Beatriz Monteiro; Hamani, Clement; Covolan, Luciene

    2015-01-01

    Magnetic resonance imaging (MRI) is an excellent non-invasive tool to investigate biological systems. The administration of the paramagnetic divalent ion manganese (Mn(2+)) enhances MRI contrast in vivo. Due to similarities between Mn(2+) and calcium (Ca(2+)), the premise of manganese-enhanced MRI (MEMRI) is that the former may enter neurons and other excitable cells through voltage-gated Ca(2+) channels. As such, MEMRI has been used to trace neuronal pathways, define morphological boundaries, and study connectivity in morphological and functional imaging studies. In this article, we provide a brief overview of MEMRI and discuss recently published data to illustrate the usefulness of this method, particularly in animal models. PMID:26217304

  8. Manganese-Enhanced MRI: Biological Applications in Neuroscience

    PubMed Central

    Malheiros, Jackeline Moraes; Paiva, Fernando Fernandes; Longo, Beatriz Monteiro; Hamani, Clement; Covolan, Luciene

    2015-01-01

    Magnetic resonance imaging (MRI) is an excellent non-invasive tool to investigate biological systems. The administration of the paramagnetic divalent ion manganese (Mn2+) enhances MRI contrast in vivo. Due to similarities between Mn2+ and calcium (Ca2+), the premise of manganese-enhanced MRI (MEMRI) is that the former may enter neurons and other excitable cells through voltage-gated Ca2+ channels. As such, MEMRI has been used to trace neuronal pathways, define morphological boundaries, and study connectivity in morphological and functional imaging studies. In this article, we provide a brief overview of MEMRI and discuss recently published data to illustrate the usefulness of this method, particularly in animal models. PMID:26217304

  9. Engineering Gd-loaded nanoparticles to enhance MRI sensitivity via T1 shortening

    PubMed Central

    Bruckman, Michael A.; Yu, Xin; Steinmetz, Nicole F.

    2013-01-01

    Magnetic resonance imaging (MRI) is a noninvasive imaging technique capable of obtaining high-resolution anatomical images of the body. Major drawbacks of MRI are the low contrast agent sensitivity and inability to distinguish healthy tissue from diseased tissue, making early detection challenging. To address this technological hurdle, paramagnetic contrast agents have been developed to increase the longitudinal relaxivity (R1), leading to an increased signal-to-noise ratio. This review focuses on methods and principles that enabled the design and engineering of nanoparticles to deliver contrast agents with enhanced ionic relaxivities. Different engineering strategies and nanoparticle platforms will be compared in terms of their manufacturability, biocompatibility properties, and their overall potential to make an impact in clinical MR imaging. PMID:24158750

  10. Contrast-enhanced MRI of murine myocardial infarction - part II.

    PubMed

    Coolen, Bram F; Paulis, Leonie E M; Geelen, Tessa; Nicolay, Klaas; Strijkers, Gustav J

    2012-08-01

    Mouse models are increasingly used to study the pathophysiology of myocardial infarction in vivo. In this area, MRI has become the gold standard imaging modality, because it combines high spatial and temporal resolution functional imaging with a large variety of methods to generate soft tissue contrast. In addition, (target-specific) MRI contrast agents can be employed to visualize different processes in the cascade of events following myocardial infarction. Here, the MRI sequence has a decisive role in the detection sensitivity of a contrast agent. However, a straightforward translation of clinically available protocols for human cardiac imaging to mice is not feasible, because of the small size of the mouse heart and its extremely high heart rate. This has stimulated intense research in the development of cardiac MRI protocols specifically tuned to the mouse with regard to timing parameters, acquisition strategies, and ECG- and respiratory-triggering methods to find an optimal trade-off between sensitivity, scan time, and image quality. In this review, a detailed analysis is given of the pros and cons of different mouse cardiac MR imaging methodologies and their application in contrast-enhanced MRI of myocardial infarction. PMID:22311260

  11. The cerebral intravascular enhancement sign is not specific: a contrast-enhanced MRI study.

    PubMed

    Bakshi, R; Kinkel, W R; Bates, V E; Mechtler, L L; Kinkel, P R

    1999-02-01

    The intravascular enhancement (IVE) sign, also known as the "arterial enhancement sign", is an abnormal finding in the brain on contrast-enhanced MRI studies. IVE has been described in arterial cerebrovascular disorders, most commonly in acute or subacute arterial ischemic infarcts. However, the specificity of this sign has not been established. We describe four patients with disorders other than arterial strokes in whom gadolinium-enhanced high-field (1.5 T) MRI suggested IVE. The conditions were herpes simplex viral encephalitis, idiopathic cerebellitis, pneumococcal meningitis, and superior sagittal sinus thrombosis with venous infarction. IVE in these cases may be due to multiple factors, including arterial, venous, perivascular, and leptomeningeal or sulcal contrast medium accumulation. Our observations suggest that arterial ischemia, previously described as the cardinal cause of IVE, probably does not explain all instances, and urge caution in interpreting this sign as a specific MRI manifestation of acute arterial infarction or ischemia. PMID:10090599

  12. A Rim-Enhanced Mass with Central Cystic Changes on MR Imaging: How to Distinguish Breast Cancer from Inflammatory Breast Diseases?

    PubMed Central

    Wang, Lijun; Wang, Dengbin; Fei, Xiaochun; Ruan, Mei; Chai, Weimin; Xu, Lin; Li, Xiaoxiao

    2014-01-01

    Objective To evaluate the capacity of magnetic resonance imaging (MRI) to distinguish breast cancer from inflammatory breast diseases manifesting as a rim-enhanced mass with central cystic changes. Materials and Methods Forty cases of breast cancer and 52 of inflammatory breast diseases showing a rim-enhanced mass with central cystic changes were retrospectively reviewed. All cases underwent dynamic contrast-enhanced MRI and 31 of them underwent diffusion-weighted imaging (DWI). Morphological features, dynamic parameters and apparent diffusion coefficient (ADC) values were comparatively analyzed using univariate analysis and binary logistic regression analysis. Results Breast cancer had a significantly thicker wall than the inflammatory breast diseases (P<0.001) while internal enhancing septa were more common in inflammatory breast diseases (P?=?0.003). On DWI, 86.7% of breast cancers demonstrate a peripheral hyperintensity whereas 93.8% of inflammatory breast diseases had a central hyperintensity (P<0.001). Compared to the inflammatory breast diseases, breast cancers had a lower ADC value for the wall (1.0910?3 mm2/s vs 1.4210?3 mm2/s, P<0.001) and a higher ADC value for the central part (1.9410?3 mm2/s vs 1.0510?3 mm2/s, P<0.001). Conclusions Both breast cancer and inflammatory breast diseases could present as a rim-enhanced mass with central cystic changes on MRI. Integrated analysis of the MR findings can allow for an accurate differential diagnosis. PMID:24598845

  13. Radiologic-Pathologic Correlations of Fibrosarcomatous Dermatofibrosarcoma Protuberans With Various Histological Features on Enhanced MRI and PET/MRI.

    PubMed

    Hakozaki, Michiyuki; Yamada, Hitoshi; Hasegawa, Osamu; Watanabe, Kazuo; Konno, Shinichi

    2016-03-01

    Dermatofibrosarcoma protuberans (DFSP) is a cutaneous tumor of intermediate-grade malignant potential, and it rarely shows dedifferentiation to high-grade fibrosarcoma, which is called "fibrosarcomatous DFSP." We present the enhanced MRI and PET/MRI findings and our comparison with pathological findings in a case of fibrosarcomatous DFSP with various histological features. PMID:26704730

  14. 78 FR 12329 - Distinguishing Medical Device Recalls From Product Enhancements; Reporting Requirements; Draft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-22

    ... HUMAN SERVICES Food and Drug Administration Distinguishing Medical Device Recalls From Product... clarify for industry when a potential change to a device is a medical device recall, distinguish those... single copies of the draft guidance document entitled ``Distinguishing Medical Device Recalls...

  15. Dynamic Contrast-Enhanced MRI Evaluation of Cerebral Cavernous Malformations

    PubMed Central

    Hart, B. L.; Taheri, S.; Rosenberg, G. A.; Morrison, L. A.

    2013-01-01

    The aim of this study is to quantitatively evaluate the behavior of CNS cavernous malformations (CCMs) using a dynamic contrast-enhanced MRI (DCEMRI) technique sensitive for slow transfer rates of gadolinium. The prospective study was approved by the institutional review board and was HIPPA compliant. Written informed consent was obtained from 14 subjects with familial CCMs (4 men and 10 women, ages 2276 years, mean 48.1 years). Following routine anatomic MRI of the brain, DCEMRI was performed for six slices, using T1 mapping with partial inversion recovery (TAPIR) to calculate T1 values, following administration of 0.025 mmol/kg gadolinium DTPA. The transfer rate (Ki) was calculated using the Patlak model, and Ki within CCMs was compared to normal-appearing white matter as well as to 17 normal control subjects previously studied. All subjects had typical MRI appearance of CCMs. Thirty-nine CCMs were studied using DCEMRI. Ki was low or normal in 12 lesions and elevated from 1.4 to 12 times higher than background in the remaining 27 lesions. Ki ranged from 2.1E6 to 9.63E4 min?1, mean 3.55E4. Normal-appearing white matter in the CCM patients had a mean Ki of 1.57E4, not statistically different from mean WM Ki of 1.47E4 in controls. TAPIR-based DCEMRI technique permits quantifiable assessment of CCMs in vivo and reveals considerable differences not seen with conventional MRI. Potential applications include correlation with biologic behavior such as lesion growth or hemorrage, and measurement of drug effects. PMID:24323376

  16. Dynamic contrast-enhanced MRI evaluation of cerebral cavernous malformations.

    PubMed

    Hart, Blaine L; Taheri, Saeid; Rosenberg, Gary A; Morrison, Leslie A

    2013-10-01

    The aim of this study is to quantitatively evaluate the behavior of CNS cavernous malformations (CCMs) using a dynamic contrast-enhanced MRI (DCEMRI) technique sensitive for slow transfer rates of gadolinium. The prospective study was approved by the institutional review board and was HIPPA compliant. Written informed consent was obtained from 14 subjects with familial CCMs (4 men and 10 women, ages 22-76 years, mean 48.1 years). Following routine anatomic MRI of the brain, DCEMRI was performed for six slices, using T1 mapping with partial inversion recovery (TAPIR) to calculate T1 values, following administration of 0.025 mmol/kg gadolinium DTPA. The transfer rate (Ki) was calculated using the Patlak model, and Ki within CCMs was compared to normal-appearing white matter as well as to 17 normal control subjects previously studied. All subjects had typical MRI appearance of CCMs. Thirty-nine CCMs were studied using DCEMRI. Ki was low or normal in 12 lesions and elevated from 1.4 to 12 times higher than background in the remaining 27 lesions. Ki ranged from 2.1E-6 to 9.63E-4 min(-1), mean 3.55E-4. Normal-appearing white matter in the CCM patients had a mean Ki of 1.57E-4, not statistically different from mean WM Ki of 1.47E-4 in controls. TAPIR-based DCEMRI technique permits quantifiable assessment of CCMs in vivo and reveals considerable differences not seen with conventional MRI. Potential applications include correlation with biologic behavior such as lesion growth or hemorrage, and measurement of drug effects. PMID:24323376

  17. The intravertebral cleft in benign vertebral compression fracture: the diagnostic performance of non-enhanced MRI and fat-suppressed contrast-enhanced MRI.

    PubMed

    Ryu, C-W; Han, H; Lee, Y-M; Lim, M-K

    2009-12-01

    We compared the diagnostic performance of non-enhanced MRI and fat-suppressed contrast-enhanced MRI (CEMRI) in diagnosing intravertebral clefts in benign vertebral compression fractures (VCFs). We retrospectively reviewed 99 consecutive patients who had undergone percutaneous vertebroplasty for VCFs. A cleft was defined as a signal void or hyperintense area on non-enhanced MRI (T(1) and T(2) weighted imaging) or as a hypointense area within a diffusely enhanced vertebra on CEMRI. A cleft was confirmed as a solid opacification on post-procedural radiographs. The interobserver reliability and MRI diagnostic performance were evaluated. The interobserver reliability of non-enhanced MRI was substantial (k _ 0.698) and the interobserver reliability of CEMRI was almost perfect (k _ 0.836). Post-procedural radiographs showed solid cleft opacification in 32 out of the 99 cases. The sensitivity and specificity of non-enhanced MRI were 0.72 and 0.82 (observer 1) and 0.63 and 0.87 (observer 2), respectively. The sensitivity and specificity of CEMRI were 0.94 and 0.63 (observer 1) and 0.85 and 0.60 (observer 2), respectively. The sensitivity of CEMRI was significantly higher than that of non-enhanced MRI, and the specificity of non-enhanced MRI was higher than that of CEMRI. CEMRI was highly reliable and sensitive, and non-enhanced MRI was specific for intravertebral clefts. Therefore, spine MRIs, including CEMRI, could provide useful information about intravertebral clefts before percutaneous vertebroplasty. PMID:19581311

  18. Distinguishing adjacent molecules on a surface using plasmon-enhanced Raman scattering

    NASA Astrophysics Data System (ADS)

    Jiang, Song; Zhang, Yao; Zhang, Rui; Hu, Chunrui; Liao, Menghan; Luo, Yi; Yang, Jinlong; Dong, Zhenchao; Hou, J. G.

    2015-10-01

    Unambiguous chemical identification of individual molecules closely packed on a surface can offer the possibility to address single chemical species and monitor their behaviour at the individual level. Such a degree of spatial resolution can in principle be achieved by detecting their vibrational fingerprints using tip-enhanced Raman scattering (TERS). The chemical specificity of TERS can be combined with the high spatial resolution of scanning probe microscopy techniques, an approach that has stimulated extensive research in the field. Recently, the development of nonlinear TERS in a scanning tunnelling microscope has pushed the spatial resolution down to ∼0.5 nm, allowing the identification of the vibrational fingerprints of isolated molecules on Raman-silent metal surfaces. Although the nonlinear TERS component is likely to help sharpen the optical contrast of the acquired image, the TERS signal still contains a considerable contribution from the linear term, which is spatially less confined. Therefore, in the presence of different adjacent molecules, a mixing of Raman signals may result. Here, we show that using a nonlinear scanning tunnelling microscope-controlled TERS set-up, two different adjacent molecules that are within van der Waals contact and of very similar chemical structure (a metal-centred porphyrin and a free-base porphyrin) on a silver surface can be distinguished in real space. In addition, with the help of density functional theory simulations, we are also able to determine their adsorption configurations and orientations on step edges and terraces.

  19. Differentiation of solid pancreatic tumors by using dynamic contrast-enhanced MRI

    NASA Astrophysics Data System (ADS)

    Choi, Seung Joon; Kim, Hyung Sik; Park, Hyunjin

    2014-01-01

    Distinguishing among different solid pancreatic tumor types, pancreatic ductal adenocarcinomas, neuroendocrine tumors (NETs), and solid pseudopapillary tumors (SPTs) is important, as the treatment options are vastly different. This study compared characteristics of solid pancreatic tumors by using dynamic contrast enhanced magnetic resonance imaging (MRI). Fifty patients underwent MR imaging of pancreatic masses with a histopathology that was later confirmed as an adenocarcinoma (n = 27), a NET (n = 16), and a SPT (n = 7). For qualitative analysis, two reviewers evaluated the morphologic features of the tumors: locations, margins, shapes, contained products, pancreatic ductal dilatation, and grade of signal intensity (SI). For the quantitative analysis, all phases of the MR images were co-registered using proprietary image registration software; thus, a region of interest (ROI) defined on one phase could be re-applied in other phases. The following four ratios were considered: tumor-to-uninvolved pancreas SI ratio, percent SI change, tumor-touninvolved pancreas enhancement index, and arterial-to-delayed washout rate. The areas under the receiver operating characteristic (ROC) curves were assessed for the four ratios. Adenocarcinomas had ill-defined margins, irregular shapes, and ductal dilatation compared with NETs and SPTs (P < 0.001). The tumor-to-uninvolved pancreas ratio on all dynamic phases was significantly higher for NETs than for both adenocarcinomas and SPTs (P < 0.05). Percentage SI changes of pancreatic tumors on the pancreatic and the portal venous phases were significantly higher for NETs than for both adenocarcinomas and SPTs (P < 0.05). A significant difference between NETs and adenocarcinomas was also found with respect to the tumor-to-uninvolved pancreas enhancement index and arterial-to-delayed washout rate. The percentage SI changes in the pancreatic phase and the arterial-to-delayed washout rate best distinguished between adenocarcinomas and NETs with the area under the ROC curve being 0.87. The percentage SI changes in the pancreatic and the portal venous phases best distinguished between NETs and SPTs with area under the ROC curve 0.87. In summary, contrast-enhanced MRI can be useful in differentiating solid pancreatic tumors in qualitative and quantitative analyses.

  20. Diffusion-weighted imaging and dynamic contrast-enhanced MRI in assessing response and recurrent disease in gynaecological malignancies.

    PubMed

    Hameeduddin, Ayshea; Sahdev, Anju

    2015-01-01

    Magnetic resonance imaging (MRI) has an established role in imaging pelvic gynaecological malignancies. It is routinely used in staging endometrial and cervical cancer, characterizing adnexal masses, selecting optimal treatment, monitoring treatment and detecting recurrent disease. MRI has also been shown to have an excellent performance and an evolving role in surveillance of patients after chemoradiotherapy in cervical cancer, post-trachelectomy, detecting early recurrence and planning exenterative surgery in isolated central recurrences in both cervical and endometrial cancer and in young patients on surveillance for medically managed endometrial cancer. However, conventional MRI still has limitations when the morphological appearance of early recurrent or residual disease overlaps with normal pelvic anatomy or treatment effects in the pelvis. In particular, after chemoradiotherapy for cervical cancer, distinguishing between radiotherapy changes and residual or early recurrent disease within the cervix or the vaginal vault can be challenging on conventional MRI alone. Therefore, there is an emerging need for functional imaging to overcome these limitations. The purpose of this paper is to discuss the emerging functional MRI techniques and their applications in predicting treatment response, detecting residual disease and early recurrent disease to optimize the treatment options available using diffusion-weighted imaging and dynamic contrast enhancement particularly in cervical and endometrial cancer. PMID:25889065

  1. MRI in cardiac electrophysiology: the emerging role of delayed-enhancement MRI in atrial fibrillation ablation.

    PubMed

    Badger, Troy J; Adjei-Poku, Yaw A; Marrouche, Nassir F

    2009-01-01

    Catheter ablation of atrial fibrillation has emerged as a viable therapeutic option for those patients who have failed conventional medical therapy. This treatment strategy has been introduced in the past decade following the discovery of ectopic foci in the pulmonary veins capable of initiating this arrhythmia. The basis of current ablation techniques relies on inducing myocardial necrosis at distinct anatomical landmarks in order to electrically isolate these ectopic foci and to disrupt pulmonary vein and left atrial conduction pathways. The recent introduction of a delayed-enhancement cardiac MRI sequence now allows for the noninvasive assessment of the location and extent of left atrial scarring following the ablation procedure. In this review, we describe this novel scan sequence and its current and potential role in catheter ablation of atrial fibrillation. PMID:19371204

  2. Use of iron colloid-enhanced MRI for study of acute radiation-induced hepatic injury

    SciTech Connect

    Suto, Yuji; Ametani, Masaki; Kato, Takashi; Hashimoto, Masayuki; Kamba, Masayuki; Sugihara, Syuji; Ohta, Yoshio

    1996-03-01

    We present a case with acute radiation-induced hepatic injury using chondroitin sulfate iron colloid (CSIC)-enhanced MRI. Uptake of CSIC was decreased in the irradiated portion of the liver. CSIC-enhanced MRI is useful for obtaining information on the function of the reticuloendothelial system and demarcates between irradiated and nonirradiated zones. 18 refs., 3 figs

  3. Identifying Triple-Negative Breast Cancer Using Background Parenchymal Enhancement Heterogeneity on Dynamic Contrast-Enhanced MRI: A Pilot Radiomics Study

    PubMed Central

    Wang, Jeff; Kato, Fumi; Oyama-Manabe, Noriko; Li, Ruijiang; Cui, Yi; Tha, Khin Khin; Yamashita, Hiroko; Kudo, Kohsuke; Shirato, Hiroki

    2015-01-01

    Objectives To determine the added discriminative value of detailed quantitative characterization of background parenchymal enhancement in addition to the tumor itself on dynamic contrast-enhanced (DCE) MRI at 3.0 Tesla in identifying “triple-negative" breast cancers. Materials and Methods In this Institutional Review Board-approved retrospective study, DCE-MRI of 84 women presenting 88 invasive carcinomas were evaluated by a radiologist and analyzed using quantitative computer-aided techniques. Each tumor and its surrounding parenchyma were segmented semi-automatically in 3-D. A total of 85 imaging features were extracted from the two regions, including morphologic, densitometric, and statistical texture measures of enhancement. A small subset of optimal features was selected using an efficient sequential forward floating search algorithm. To distinguish triple-negative cancers from other subtypes, we built predictive models based on support vector machines. Their classification performance was assessed with the area under receiver operating characteristic curve (AUC) using cross-validation. Results Imaging features based on the tumor region achieved an AUC of 0.782 in differentiating triple-negative cancers from others, in line with the current state of the art. When background parenchymal enhancement features were included, the AUC increased significantly to 0.878 (p<0.01). Similar improvements were seen in nearly all subtype classification tasks undertaken. Notably, amongst the most discriminating features for predicting triple-negative cancers were textures of background parenchymal enhancement. Conclusions Considering the tumor as well as its surrounding parenchyma on DCE-MRI for radiomic image phenotyping provides useful information for identifying triple-negative breast cancers. Heterogeneity of background parenchymal enhancement, characterized by quantitative texture features on DCE-MRI, adds value to such differentiation models as they are strongly associated with the triple-negative subtype. Prospective validation studies are warranted to confirm these findings and determine potential implications. PMID:26600392

  4. Distinguishing specific sexual and general emotional effects in fMRI-subcortical and cortical arousal during erotic picture viewing.

    PubMed

    Walter, Martin; Bermpohl, Felix; Mouras, Harold; Schiltz, Kolja; Tempelmann, Claus; Rotte, Michael; Heinze, Hans Jochen; Bogerts, Bernhard; Northoff, Georg

    2008-05-01

    Sexual activity involves excitement with high arousal and pleasure as typical features of emotions. Brain activations specifically related to erotic feelings and those related to general emotional processing are therefore hard to disentangle. Using fMRI in 21 healthy subjects (11 males and 10 females), we investigated regions that show activations specifically related to the viewing of sexually intense pictures while controlling for general emotional arousal (GEA) or pleasure. Activations in the ventral striatum and hypothalamus were found to be modulated by the stimulus' specific sexual intensity (SSI) while activations in the anterior cingulate cortex were associated with an interaction between sexual intensity and emotional valence. In contrast, activation in other regions like the dorsomedial prefrontal cortex, the mediodorsal thalamus and the amygdala was associated only with a general emotional component during sexual arousal. No differences were found in these effects when comparing females and males. Our findings demonstrate for the first time neural differentiation between emotional and sexual components in the neural network underlying sexual arousal. PMID:18329905

  5. Curvelet processing of MRI for local image enhancement.

    PubMed

    Tsai, Kunyu; Ma, Jianwei; Ye, Datian; Wu, Jian

    2012-01-01

    Magnetic resonance imaging provides very good contrast between different soft tissues; however, in some cases, this technique is not so suitable to image calcified structures like bones. The quality of images is often degraded by blur edges or noises, which makes it difficult to accurately identify bone structures. In this paper, we proposed a new curvelet preprocessing method for local image enhancement to especially improve the quality of spinal MRI. Our objective is to both sharpen boundaries and smoothen the intensity variation of the vertebra. In the first phase, we extract features through curvelet coefficients and the gradient of the original image, then we utilize fuzzy cluster method to classify the whole image scope into the 'edge' region and the 'nonedge' region. In the second phase, we locally sharpen or smoothen the image by adaptive adjustment of curvelet coefficients and Gaussian smoothing method in different subregions. To evaluate the effect of the preprocessing method, we examine the gradient of the image and its segmentation results as the assessments. The experiment results show that the feature extraction method is effective for classification and the vertebra performs higher contrast on boundaries and less noises after the enhancement, which indeed helps increase the accuracy of further segmentation. PMID:25364844

  6. Benefits of dynamic susceptibility-weighted contrast-enhanced perfusion MRI for glioma diagnosis and therapy

    PubMed Central

    Barajas, Ramon Francisco; Cha, Soonmee

    2014-01-01

    SUMMARY Glioma are the most common supra-tentorial brain tumor in the USA with an estimated annual incidence of 17,000 new cases per year. Dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion MRI noninvasively characterizes tumor biology allowing for the diagnosis and therapeutic monitoring of glioma. This MRI technique utilizes the rapid changes in signal intensity caused by a rapid intravascular bolus of paramagnetic contrast agent to calculate physiologic perfusion metrics. DSC perfusion MRI has increasingly become an integrated part of glioma imaging. The specific aim of this article is to review the benefits of DSC perfusion MRI in the therapy of glioma. PMID:25438812

  7. Ultrafast 3D spin-echo acquisition improves Gadolinium-enhanced MRI signal contrast enhancement

    PubMed Central

    Han, S. H.; Cho, F. H.; Song, Y. K.; Paulsen, J.; Song, Y. Q.; Kim, Y. R.; Kim, J. K.; Cho, G.; Cho, H.

    2014-01-01

    Long scan times of 3D volumetric MR acquisitions usually necessitate ultrafast in vivo gradient-echo acquisitions, which are intrinsically susceptible to magnetic field inhomogeneities. This is especially problematic for contrast-enhanced (CE)-MRI applications, where non-negligible T2* effect of contrast agent deteriorates the positive signal contrast and limits the available range of MR acquisition parameters and injection doses. To overcome these shortcomings without degrading temporal resolution, ultrafast spin-echo acquisitions were implemented. Specifically, a multiplicative acceleration factor from multiple spin echoes (32) and compressed sensing (CS) sampling (8) allowed highly-accelerated 3D Multiple-Modulation-Multiple-Echo (MMME) acquisition. At the same time, the CE-MRI of kidney with Gd-DOTA showed significantly improved signal enhancement for CS-MMME acquisitions (7) over that of corresponding FLASH acquisitions (2). Increased positive contrast enhancement and highly accelerated acquisition of extended volume with reduced RF irradiations will be beneficial for oncological and nephrological applications, in which the accurate in vivo 3D quantification of contrast agent concentration is necessary with high temporal resolution. PMID:24863102

  8. Emerging role of contrast-enhanced MRI in diagnosing vascular malformations.

    PubMed

    Turley, Ryan S; Lidsky, Michael E; Markovic, Jovan N; Shortell, Cynthia K

    2014-07-01

    Vascular malformations comprise a diverse and rare group of lesions which generally pose a formidable treatment challenge. Requisite for optimal surgical planning are imaging modalities capable of delineating involved anatomy and malformation flow characteristics. In this regard, we and others have purported the advantages of contrast-enhanced MRI. Here, we review the current body of literature regarding the emerging of role of contrast enhanced MRI for the management of vascular malformations. PMID:25301311

  9. Enhanced basal and disorderly growth hormone secretion distinguish acromegalic from normal pulsatile growth hormone release.

    PubMed Central

    Hartman, M L; Pincus, S M; Johnson, M L; Matthews, D H; Faunt, L M; Vance, M L; Thorner, M O; Veldhuis, J D

    1994-01-01

    Pulses of growth hormone (GH) release in acromegaly may arise from hypothalamic regulation or from random events intrinsic to adenomatous tissue. To distinguish between these possibilities, serum GH concentrations were measured at 5-min intervals for 24 h in acromegalic men and women with active (n = 19) and inactive (n = 9) disease and in normal young adults in the fed (n = 20) and fasted (n = 16) states. Daily GH secretion rates, calculated by deconvolution analysis, were greater in patients with active acromegaly than in fed (P < 0.05) but not fasted normal subjects. Significant basal (nonpulsatile) GH secretion was present in virtually all active acromegalics but not those in remission or in fed and fasted normal subjects. A recently introduced scale- and model-independent statistic, approximate entropy (ApEn), was used to test for regularity (orderliness) in the GH data. All but one acromegalic had ApEn values greater than the absolute range in normal subjects, indicating reduced orderliness of GH release; ApEn distinguished acromegalic from normal GH secretion (fed, P < 10(-12); fasted, P < 10(-7)) with high sensitivity (95%) and specificity (100%). Acromegalics in remission had ApEn scores larger than those of normal subjects (P < 0.0001) but smaller than those of active acromegalics (P < 0.001). The coefficient of variation of successive incremental changes in GH concentrations was significantly lower in acromegalics than in normal subjects (P < 0.001). Fourier analysis in acromegalics revealed reduced fractional amplitudes compared to normal subjects (P < 0.05). We conclude that GH secretion in acromegaly is highly irregular with disorderly release accompanying significant basal secretion. Images PMID:8083369

  10. Human Tumor Cell Proliferation Evaluated Using Manganese-Enhanced MRI

    PubMed Central

    Braun, Rod D.; Bissig, David; North, Robert; Vistisen, Kerry S.; Berkowitz, Bruce A.

    2012-01-01

    Background Tumor cell proliferation can depend on calcium entry across the cell membrane. As a first step toward the development of a non-invasive test of the extent of tumor cell proliferation in vivo, we tested the hypothesis that tumor cell uptake of a calcium surrogate, Mn2+ [measured with manganese-enhanced MRI (MEMRI)], is linked to proliferation rate in vitro. Methodology/Principal Findings Proliferation rates were determined in vitro in three different human tumor cell lines: C918 and OCM-1 human uveal melanomas and PC-3 prostate carcinoma. Cells growing at different average proliferation rates were exposed to 1 mM MnCl2 for one hour and then thoroughly washed. MEMRI R1 values (longitudinal relaxation rates), which have a positive linear relationship with Mn2+ concentration, were then determined from cell pellets. Cell cycle distributions were determined using propidium iodide staining and flow cytometry. All three lines showed Mn2+-induced increases in R1 compared to cells not exposed to Mn2+. C918 and PC-3 cells each showed a significant, positive correlation between MEMRI R1 values and proliferation rate (p?0.005), while OCM-1 cells showed no significant correlation. Preliminary, general modeling of these positive relationships suggested that pellet R1 for the PC-3 cells, but not for the C918 cells, could be adequately described by simply accounting for changes in the distribution of the cell cycle-dependent subpopulations in the pellet. Conclusions/Significance These data clearly demonstrate the tumor-cell dependent nature of the relationship between proliferation and calcium influx, and underscore the usefulness of MEMRI as a non-invasive method for investigating this link. MEMRI is applicable to study tumors in vivo, and the present results raise the possibility of evaluating proliferation parameters of some tumor types in vivo using MEMRI. PMID:22363447

  11. Diffuse dural gadolinium MRI enhancement associated with bilateral chronic subdural hematomas.

    PubMed

    Blitshteyn, Svetlana; Mechtler, Laszlo L; Bakshi, Rohit

    2004-01-01

    Chronic subdural hematomas (CSDHs) typically present with cognitive dysfunction and a history of trauma. Localized dural enhancement on postcontrast MRI scans associated with the surrounding membrane has been described in CSDH. We present an 83-year-old man with rapidly progressing cognitive dysfunction 4 weeks after head trauma related to a fall. MRI showed CSDHs, which in addition to localized dural gadolinium enhancement, showed a marked diffuse, symmetric, contiguous pachymeningeal enhancement of the supratentorial and infratentorial intracranial dural mater. Meningeal biopsy failed to disclose an infectious or neoplastic cause of the enhancement and instead showed fibrocollagenous change. We conclude that diffuse dural enhancement on MRI scans associated with CSDH cause does not necessarily indicate a superimposed process such as infection or malignancy. CSDH should be considered in the differential diagnosis of diffuse dural enhancement, especially when supported by appropriate clinical findings. PMID:15050219

  12. Use of an internal reference in semi-quantitative dynamic contrast-enhanced MRI (DCE MRI) of indeterminate adnexal masses

    PubMed Central

    Benardin, L; Booth, T C; Miquel, M E; Dilks, P; Sahdev, A; Rockall, A G

    2014-01-01

    Objective: Semi-quantitative dynamic contrast-enhanced MRI (DCE MRI) has proven useful in discriminating benign from borderline/malignant adnexal lesions. Our aim was to assess if the use of a lesion-to-internal-reference ratio improved the performance in characterizing adnexal masses and which internal reference was suitable. Methods: Semi-quantitative DCE MRI images of 71 indeterminate adnexal lesions were retrospectively reviewed. A region of interest was manually drawn onto the enhancing solid component, psoas muscle and normal outer myometrium. The DCE parameters were evaluated, and the lesion-to-internal-reference ratios were calculated. Results: When the wash in rate of the lesion was higher than that of the myometrium, 97% specificity and 12% sensitivity for borderline/malignancy was reached. When the maximum relative enhancement and maximum absolute enhancement (SImax) of the lesion was less than those of the psoas, 100% specificity for benignity was achieved. The highest area under the curve (AUC) (0.807) was achieved using a SImax lesionmyometrium ratio. A slightly lower AUC (0.799) was achieved using a SImax lesionpsoas ratio, but the psoas muscle was more frequently measurable in the same slice as the lesion ROI. Although the AUC was higher, when using ratios instead of individual DCE values, this was not significantly different. Conclusion: DCE MRI has added diagnostic value in the assessment of adnexal lesions, and the use of internal references enables high specificity for malignancy and benignity. Lesioninternal-reference ratios have no added diagnostic value over DCE values alone. Advances in knowledge: Both psoas muscle and myometrium are suitable internal references in the DCE assessment of adnexal lesions enabling high specificity for malignancy and benignity. PMID:25237836

  13. In vivo visuotopic brain mapping with manganese-enhanced MRI and resting-state functional connectivity MRI.

    PubMed

    Chan, Kevin C; Fan, Shu-Juan; Chan, Russell W; Cheng, Joe S; Zhou, Iris Y; Wu, Ed X

    2014-04-15

    The rodents are an increasingly important model for understanding the mechanisms of development, plasticity, functional specialization and disease in the visual system. However, limited tools have been available for assessing the structural and functional connectivity of the visual brain network globally, in vivo and longitudinally. There are also ongoing debates on whether functional brain connectivity directly reflects structural brain connectivity. In this study, we explored the feasibility of manganese-enhanced MRI (MEMRI) via 3 different routes of Mn(2+) administration for visuotopic brain mapping and understanding of physiological transport in normal and visually deprived adult rats. In addition, resting-state functional connectivity MRI (RSfcMRI) was performed to evaluate the intrinsic functional network and structural-functional relationships in the corresponding anatomical visual brain connections traced by MEMRI. Upon intravitreal, subcortical, and intracortical Mn(2+) injection, different topographic and layer-specific Mn enhancement patterns could be revealed in the visual cortex and subcortical visual nuclei along retinal, callosal, cortico-subcortical, transsynaptic and intracortical horizontal connections. Loss of visual input upon monocular enucleation to adult rats appeared to reduce interhemispheric polysynaptic Mn(2+) transfer but not intra- or inter-hemispheric monosynaptic Mn(2+) transport after Mn(2+) injection into visual cortex. In normal adults, both structural and functional connectivity by MEMRI and RSfcMRI was stronger interhemispherically between bilateral primary/secondary visual cortex (V1/V2) transition zones (TZ) than between V1/V2 TZ and other cortical nuclei. Intrahemispherically, structural and functional connectivity was stronger between visual cortex and subcortical visual nuclei than between visual cortex and other subcortical nuclei. The current results demonstrated the sensitivity of MEMRI and RSfcMRI for assessing the neuroarchitecture, neurophysiology and structural-functional relationships of the visual brains in vivo. These may possess great potentials for effective monitoring and understanding of the basic anatomical and functional connections in the visual system during development, plasticity, disease, pharmacological interventions and genetic modifications in future studies. PMID:24394694

  14. Major mouse placental compartments revealed by diffusion-weighted MRI, contrast-enhanced MRI, and fluorescence imaging

    PubMed Central

    Solomon, Eddy; Avni, Reut; Hadas, Ron; Raz, Tal; Garbow, Joel Richard; Bendel, Peter; Frydman, Lucio; Neeman, Michal

    2014-01-01

    Mammalian models, and mouse studies in particular, play a central role in our understanding of placental development. Magnetic resonance imaging (MRI) could be a valuable tool to further these studies, providing both structural and functional information. As fluid dynamics throughout the placenta are driven by a variety of flow and diffusion processes, diffusion-weighted MRI could enhance our understanding of the exchange properties of maternal and fetal blood poolsand thereby of placental function. These studies, however, have so far been hindered by the small sizes, the unavoidable motions, and the challenging air/water/fat heterogeneities, associated with mouse placental environments. The present study demonstrates that emerging methods based on the spatiotemporal encoding (SPEN) of the MRI information can robustly overcome these obstacles. Using SPEN MRI in combination with albumin-based contrast agents, we analyzed the diffusion behavior of developing placentas in a cohort of mice. These studies successfully discriminated the maternal from the fetal blood flows; the two orders of magnitude differences measured in these fluids apparent diffusion coefficients suggest a nearly free diffusion behavior for the former and a strong flow-based component for the latter. An intermediate behavior was observed by these methods for a third compartment that, based on maternal albumin endocytosis, was associated with trophoblastic cells in the interphase labyrinth. Structural features associated with these dynamic measurements were consistent with independent intravital and ex vivo fluorescence microscopy studies and are discussed within the context of the anatomy of developing mouse placentas. PMID:24969421

  15. Recent Advances in the Imaging Diagnosis of Hepatocellular Carcinoma: Value of Gadoxetic Acid-Enhanced MRI

    PubMed Central

    Joo, Ijin; Lee, Jeong Min

    2016-01-01

    Magnetic resonance imaging (MRI) using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DPTA), or gadoxetic acid for short, is a hepatocyte-specific contrast agent which is now increasingly used for the detection and characterization of focal hepatic lesions, particularly in patients at high-risk of developing hepatocellular carcinomas (HCC). In fact, several recent guidelines now recognize gadoxetic acid-enhanced MRI (Gd-EOB-MRI) as the primary diagnostic imaging modality for the noninvasive diagnosis of HCC, although it must be noted that several major guidelines still include only extracellular contrast media-enhanced computed tomography and MRI. The primary merits of Gd-EOB-MRI lie in the fact that it can provide not only dynamic imaging, but also hepatobiliary phase (HBP) imaging which can lead to high lesion-to-liver contrast and give additional information regarding hepatocyte uptake via organic anion transporting polypeptides. This, in turn, allows higher sensitivity in detecting small HCCs and helps provide additional information regarding the multistep process of hepatocarcinogenesis. Indeed, many recent studies have investigated the diagnostic value of Gd-EOB-MRI for early HCCs as well as its role as a potential imaging biomarker in predicting outcome. We herein review the recent advances in the imaging diagnosis of HCCs focusing on the applications of Gd-EOB-MRI and the challenging issues that remain. PMID:26989660

  16. An Aid to Decision-Making in Therapy of Retroperitoneal Fibrosis: Dynamic Enhancement Analysis of Gadolinium MRI

    PubMed Central

    Brandt, Alexander Sascha; Kamper, Lars; Kukuk, Sonja; Piroth, Werner; Haage, Patrick; Roth, Stephan

    2013-01-01

    Background Idiopathic retroperitoneal fibrosis (IRF) as an uncommon cause of obstructive uropathy is often primarily treated medically by the attending urologist. We evaluated dynamic enhancement analysis (DEA) as a possible predictor of response to medical treatment and for treatment monitoring. Methods From 2007, 24 patients with fibrosis were assessed by magnetic resonance imaging (MRI) with DEA. The dynamic enhancement quotient (DEQ) was measured before therapy with prednisone (n = 12) or tamoxifen (n = 12) and in follow-up investigations after 3 and 6 months. Response to medical treatment was recorded by changes in the retroperitoneal mass on MRI and possible relief of ureteral obstruction, which was monitored by intravenous pyelogram and/or MAG3 scan after removal of DJ stents. Results Treatment groups did not differ significantly as to age, gender, or laboratory values, and response to medical treatment showed no significant difference between agents. Overall there were no cases of progression, 2 cases of stable disease, 11 cases of mild fibrotic regression, and 11 of significant or complete regression. DJ stents could successfully be removed in 21 of 35 renal units (60.0%). In a total of 61 DEAs the DEQ was significantly higher (P < 0.001) in patients with a good response (DEQ = 4.02) than in those with an average response (3.11) or none (2.14). Conclusions DEA was able to distinguish between patients with different response rates to medical treatment of IRF and may be useful to individualize therapeutic decision-making. PMID:23390476

  17. MRI.

    PubMed

    Silvestri, Dianne

    2016-03-01

    This poem describes the experience of having an MRI performed. The writer describes the jolting magnets against her banging heart. She closes her eyes and remembers reclining against her husband in a gondola in Venice. (PsycINFO Database Record PMID:26963782

  18. Glucose Administration Enhances fMRI Brain Activation and Connectivity Related to Episodic Memory Encoding for Neutral and Emotional Stimuli

    ERIC Educational Resources Information Center

    Parent, Marise B.; Krebs-Kraft, Desiree L.; Ryan, John P.; Wilson, Jennifer S.; Harenski, Carla; Hamann, Stephan

    2011-01-01

    Glucose enhances memory in a variety of species. In humans, glucose administration enhances episodic memory encoding, although little is known regarding the neural mechanisms underlying these effects. Here we examined whether elevating blood glucose would enhance functional MRI (fMRI) activation and connectivity in brain regions associated with

  19. Glucose Administration Enhances fMRI Brain Activation and Connectivity Related to Episodic Memory Encoding for Neutral and Emotional Stimuli

    ERIC Educational Resources Information Center

    Parent, Marise B.; Krebs-Kraft, Desiree L.; Ryan, John P.; Wilson, Jennifer S.; Harenski, Carla; Hamann, Stephan

    2011-01-01

    Glucose enhances memory in a variety of species. In humans, glucose administration enhances episodic memory encoding, although little is known regarding the neural mechanisms underlying these effects. Here we examined whether elevating blood glucose would enhance functional MRI (fMRI) activation and connectivity in brain regions associated with…

  20. Signal enhancement ratio (SER) quantified from breast DCE-MRI and breast cancer risk

    NASA Astrophysics Data System (ADS)

    Wu, Shandong; Kurland, Brenda F.; Berg, Wendie A.; Zuley, Margarita L.; Jankowitz, Rachel C.; Sumkin, Jules; Gur, David

    2015-03-01

    Breast magnetic resonance imaging (MRI) is recommended as an adjunct to mammography for women who are considered at elevated risk of developing breast cancer. As a key component of breast MRI, dynamic contrast-enhanced MRI (DCE-MRI) uses a contrast agent to provide high intensity contrast between breast tissues, making it sensitive to tissue composition and vascularity. Breast DCE-MRI characterizes certain physiologic properties of breast tissue that are potentially related to breast cancer risk. Studies have shown that increased background parenchymal enhancement (BPE), which is the contrast enhancement occurring in normal cancer-unaffected breast tissues in post-contrast sequences, predicts increased breast cancer risk. Signal enhancement ratio (SER) computed from pre-contrast and post-contrast sequences in DCE-MRI measures change in signal intensity due to contrast uptake over time and is a measure of contrast enhancement kinetics. SER quantified in breast tumor has been shown potential as a biomarker for characterizing tumor response to treatments. In this work we investigated the relationship between quantitative measures of SER and breast cancer risk. A pilot retrospective case-control study was performed using a cohort of 102 women, consisting of 51 women who had diagnosed with unilateral breast cancer and 51 matched controls (by age and MRI date) with a unilateral biopsy-proven benign lesion. SER was quantified using fully-automated computerized algorithms and three SER-derived quantitative volume measures were compared between the cancer cases and controls using logistic regression analysis. Our preliminary results showed that SER is associated with breast cancer risk, after adjustment for the Breast Imaging Reporting and Data System (BI-RADS)-based mammographic breast density measures. This pilot study indicated that SER has potential for use as a risk factor for breast cancer risk assessment in women at elevated risk of developing breast cancer.

  1. Neural Correlates of Feigned Memory Impairment are Distinguishable from Answering Randomly and Answering Incorrectly: An fMRI and Behavioral Study

    ERIC Educational Resources Information Center

    Liang, Chun-Yu; Xu, Zhi-Yuan; Mei, Wei; Wang, Li-Li; Xue, Li; Lu, De Jian; Zhao, Hu

    2012-01-01

    Previous functional magnetic resonance imaging (fMRI) studies have identified activation in the prefrontal-parietal-sub-cortical circuit during feigned memory impairment when comparing with truthful telling. Here, we used fMRI to determine whether neural activity can differentiate between answering correctly, answering randomly, answering

  2. Neural Correlates of Feigned Memory Impairment are Distinguishable from Answering Randomly and Answering Incorrectly: An fMRI and Behavioral Study

    ERIC Educational Resources Information Center

    Liang, Chun-Yu; Xu, Zhi-Yuan; Mei, Wei; Wang, Li-Li; Xue, Li; Lu, De Jian; Zhao, Hu

    2012-01-01

    Previous functional magnetic resonance imaging (fMRI) studies have identified activation in the prefrontal-parietal-sub-cortical circuit during feigned memory impairment when comparing with truthful telling. Here, we used fMRI to determine whether neural activity can differentiate between answering correctly, answering randomly, answering…

  3. Serial study of gadolinium-DTPA MRI enhancement in multiple sclerosis.

    PubMed

    Bastianello, S; Pozzilli, C; Bernardi, S; Bozzao, L; Fantozzi, L M; Buttinelli, C; Fieschi, C

    1990-04-01

    We performed serial baseline and gadolinium (Gd)-DTPA-enhanced MRI in 4 patients with definite multiple sclerosis. Studies were performed every month for a total of 4 scans. We obtained short TR/short TE sequences at 10 and 60 minutes after Gd-DTPA injection. All patients had multiple hyperintense lesions seen on baseline MRI with long TR/short and long TE. There was Gd-DTPA enhancement in new, enlarging, and preexisting lesions that were unchanged in size. The enhancing lesions were always seen on T2-weighted images. There was no difference in enhancement between the 10- and 60-minute studies. Six of 85 preexisting lesions enhanced whereas all new or enlarging lesions enhanced. Enhancement persisted in only 1/3 of the new or enlarging lesions, suggesting that MR enhancement is a transient phenomenon due to local temporary blood-brain barrier breakdown. Our data indicate that Gd-DTPA enhancement monitoring is more sensitive than unenhanced MRI for detecting disease activity in MS. PMID:2320230

  4. The Potential for an Enhanced Role for MRI in Radiation-therapy Treatment Planning

    PubMed Central

    Metcalfe, P.; Liney, G. P.; Holloway, L.; Walker, A.; Barton, M.; Delaney, G. P.; Vinod, S.; Tom, W.

    2013-01-01

    The exquisite soft-tissue contrast of magnetic resonance imaging (MRI) has meant that the technique is having an increasing role in contouring the gross tumor volume (GTV) and organs at risk (OAR) in radiation therapy treatment planning systems (TPS). MRI-planning scans from diagnostic MRI scanners are currently incorporated into the planning process by being registered to CT data. The soft-tissue data from the MRI provides target outline guidance and the CT provides a solid geometric and electron density map for accurate dose calculation on the TPS computer. There is increasing interest in MRI machine placement in radiotherapy clinics as an adjunct to CT simulators. Most vendors now offer 70 cm bores with flat couch inserts and specialised RF coil designs. We would refer to these devices as MR-simulators. There is also research into the future application of MR-simulators independent of CT and as in-room image-guidance devices. It is within the background of this increased interest in the utility of MRI in radiotherapy treatment planning that this paper is couched. The paper outlines publications that deal with standard MRI sequences used in current clinical practice. It then discusses the potential for using processed functional diffusion maps (fDM) derived from diffusion weighted image sequences in tracking tumor activity and tumor recurrence. Next, this paper reviews publications that describe the use of MRI in patient-management applications that may, in turn, be relevant to radiotherapy treatment planning. The review briefly discusses the concepts behind functional techniques such as dynamic contrast enhanced (DCE), diffusion-weighted (DW) MRI sequences and magnetic resonance spectroscopic imaging (MRSI). Significant applications of MR are discussed in terms of the following treatment sites: brain, head and neck, breast, lung, prostate and cervix. While not yet routine, the use of apparent diffusion coefficient (ADC) map analysis indicates an exciting future application for functional MRI. Although DW-MRI has not yet been routinely used in boost adaptive techniques, it is being assessed in cohort studies for sub-volume boosting in prostate tumors. PMID:23617289

  5. Dynamic Glucose-Enhanced (DGE) MRI: Translation to Human Scanning and First Results in Glioma Patients

    PubMed Central

    Xu, Xiang; Yadav, Nirbhay N.; Knutsson, Linda; Hua, Jun; Kalyani, Rita; Hall, Erica; Laterra, John; Blakeley, Jaishri; Strowd, Roy; Pomper, Martin; Barker, Peter; Chan, Kannie; Liu, Guanshu; McMahon, Michael T.; Stevens, Robert D.; van Zijl, Peter C.M.

    2015-01-01

    Recent animal studies have shown that D-glucose is a potential biodegradable MRI contrast agent for imaging glucose uptake in tumors. Here, we show the first translation of that use of D-glucose to human studies. Chemical exchange saturation transfer (CEST) MRI at a single frequency offset optimized for detection of hydroxyl protons in D-glucose (glucoCEST) was used to image dynamic signal changes in the human brain at 7T during and after infusion of D-glucose. Dynamic glucose-enhanced (DGE) image data from four normal volunteers and three glioma patients showed strong signal enhancement in blood vessels, while the enhancement varied spatially over the tumor. Areas of enhancement differed spatially between DGE and conventional Gd-enhanced imaging, suggesting complementary image information content for these two types of agents. In addition, different tumor areas enhanced with D-glucose at different times post-infusion, suggesting a sensitivity to perfusion-related properties such as substrate delivery and blood-brain barrier (BBB) permeability. These preliminary results suggest that DGE MRI is feasible to study glucose uptake in humans, providing a time-dependent set of data that contains information regarding arterial input function (AIF), tissue perfusion, glucose transport across the BBB and cell membrane, and glucose metabolism. PMID:26779568

  6. Synergistic enhancement of iron oxide nanoparticle and gadolinium for dual-contrast MRI

    SciTech Connect

    Zhang, Fan; Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 ; Huang, Xinglu; Qian, Chunqi; Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 ; Zhu, Lei; Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 ; Hida, Naoki; Niu, Gang; Chen, Xiaoyuan

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer MR contrast agents exert influence on T{sub 1} or T{sub 2} relaxation time of the surrounding tissue. Black-Right-Pointing-Pointer Combined use of iron oxide and Gd-DTPA can improve the sensitivity/specificity of lesion detection. Black-Right-Pointing-Pointer Dual contrast MRI enhances the delineation of tumor borders and small lesions. Black-Right-Pointing-Pointer The effect of DC-MRI can come from the high paramagnetic susceptibility of Gd{sup 3+}. Black-Right-Pointing-Pointer The effect of DC-MRI can also come from the distinct pharmacokinetic distribution of SPIO and Gd-DTPA. -- Abstract: Purpose: The use of MR contrast agents allows accurate diagnosis by exerting an influence on the longitudinal (T{sub 1}) or transverse (T{sub 2}) relaxation time of the surrounding tissue. In this study, we combined the use of iron oxide (IO) particles and nonspecific extracellular gadolinium chelate (Gd) in order to further improve the sensitivity and specificity of lesion detection. Procedures: With a 7-Tesla scanner, pre-contrasted, IO-enhanced and dual contrast agent enhanced MRIs were performed in phantom, normal animals, and animal models of lymph node tumor metastases and orthotopic brain tumor. For the dual-contrast (DC) MRI, we focused on the evaluation of T{sub 2} weighted DC MRI with IO administered first, then followed by the injection of a bolus of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). Results: Based on the C/N ratios and MRI relaxometry, the synergistic effect of coordinated administration of Gd-DTPA and IO was observed and confirmed in phantom, normal liver and tumor models. At 30 min after administration of Feridex, Gd-DTPA further decreased T{sub 2} relaxation in liver immediately after the injection. Additional administration of Gd-DTPA also immediately increased the signal contrast between tumor and brain parenchyma and maximized the C/N ratio to -4.12 {+-} 0.71. Dual contrast MRI also enhanced the delineation of tumor borders and small lesions. Conclusions: DC-MRI will be helpful to improve diagnostic accuracy and decrease the threshold size for lesion detection.

  7. Usefulness of contrast enhanced-MRI in the diagnosis of unicystic ameloblastoma.

    PubMed

    Konouchi, Hironobu; Asaumi, Jun-ichi; Yanagi, Yoshinobu; Hisatomi, Miki; Kawai, Noriko; Matsuzaki, Hidenobu; Kishi, Kanji

    2006-05-01

    The radiographic features of unicystic ameloblastoma (UA) are typically unilocular and round area of radiolucency. Therefore, this type of lesion is often misdiagnosed as an odontogenic keratocyst or a dentigerous cyst. UA should be differentiated from odontogenic cysts because the former have a higher rate of recurrence than the latter. In the present study, we performed contrast enhanced-MRI (CE-MRI) to diagnose 13 cases of unilocular, round radiolucent lesions visualized on panoramic radiograph and/or CT. In the cases of UA, low signal intensity was observed on T1-weighted images (WIs), and a markedly high signal intensity was observed on T2-WIs; moreover, relatively thick rim-enhancement with/without small intraluminal nodules was observed upon CE-T1WIs. CE-MRI was considered useful in the diagnosis of UA, as characteristic features of this type of lesion i.e., thick enhancement of the tumor wall and small intraluminal nodules were detected only by CE-MRI in the present study. PMID:16488178

  8. Diagnostic value of dynamic contrast-enhanced MRI for unilocular cystic-type ameloblastomas with homogeneously bright high signal intensity on T2-weighted or STIR MR images.

    PubMed

    Hisatomi, Miki; Yanagi, Yoshinobu; Konouchi, Hironobu; Matsuzaki, Hidenobu; Takenobu, Toshihiko; Unetsubo, Teruhisa; Asaumi, Jun-ichi

    2011-02-01

    Typical MR images of ameloblastomas on T2-weighted image (WI) or short inversion time inversion-recovery (STIR) show multiple bright high-signal-intensity loci on a high-signal-intensity background. Unilocular cystic-type ameloblastomas show homogeneously bright high signal intensity on T2WI or STIR as a water-like signal intensity. Therefore, it is difficult to distinguish unilocular cystic-type ameloblastoma from other cystic lesions such as keratocystic odontogenic tumors, radicular cysts (residual cysts) and dentigerous cysts only on the basis of MRI signal intensity. In the present study, we evaluated whether contrast-enhanced (CE)-T1WI and dynamic CE-MRI (DCE-MRI) could provide additional information for differential diagnosis in unilocular cystic-type ameloblastoma. Images from 12 cases of suspected unilocular cystic-type ameloblastoma were evaluated in the present study. Of them, 5 had areas suspected of indicating a solid component on T1WI and T2WI (or STIR). Ten had undergone additional CE-T1WI and DCE-MRI. On 5 of 10 cases of CE-T1WI, a tiny enhancement area was detected. On 6 of 10 DCE-images, a time-course enhanced area which was suspected to be a solid component was detected. CE-T1WI was helpful in the diagnosis of ameloblastoma because the tiny enhanced areas were taken to indicate possible solid components. Moreover, the rim-enhancement area on CE-T1WI could be divided into small regions of interest, and some of these showed slightly increased enhancement on DCE-MRI, which was taken to indicate a solid component and/or intramural nodule with focal invasion of ameloblastoma tissue. DCE-MRIs of the four remaining cases, which provided no clues to the diagnosis of ameloblastoma in the manner of the above descriptions, showed thicker rim enhancement than odontogenic cysts. Thus, CE-T1WI and DCE-MRI were helpful in the differential diagnosis of unilocular cystic-type ameloblastomas with homogeneously bright high signal intensity on T2WI or STIR. PMID:21168358

  9. Differentiation of tuberculosis and metastatic cancer in the spine using dynamic contrast-enhanced MRI

    PubMed Central

    Lang, Ning; Su, Min-Ying; Yu, Hon J.; Yuan, Huishu

    2016-01-01

    Purpose To investigate the differences between imaging features of spinal tuberculosis (TB) and metastatic cancer measured by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The presentation of TB on convention MRI may not show the typical TB signs, and they may be mis-diagnosed as malignant diseases. DCE-MRI may provide additional information to help making differential diagnosis. Materials and methods DCE-MRI was performed in 24 TB and 22 metastatic cancer patients. The DCE kinetic pattern was determined as wash-out, plateau or persistent enhancement. The characteristic DCE parameters were calculated from the signal intensity time course. The two-compartmental pharmacokinetic model was used to obtain Ktrans, which is the parameter associated with the delivery of MR contrast agents into the lesion, and kep, which is the parameter associated with the distribution and clearance of contrast agents from the lesion. Results Of the 24 TB, one case showed the wash-out kinetic pattern, 12 cases showed the plateau pattern, and 11 cases showed the persistent enhancement pattern. Of the 22 metastatic cancers, 12 cases showed wash-out, 7 cases showed plateau, and 3 cases showed persistent enhancement patterns. Compared to the metastatic cancer group, the TB group had a lower kep (0.270.15 vs. 0.490.23 min?1, P<0.001). The ROC analysis showed that the area under the curve was 0.780 for kep. Conclusions DCE-MRI may provide additional information for differentiation between spinal TB and metastasis, when their manifestations on conventional imaging were similar. PMID:25749725

  10. Atherosclerotic plaque inflammation quantification using dynamic contrast-enhanced (DCE) MRI

    PubMed Central

    Wu, Tingting; Kerwin, William S.; Yuan, Chun

    2013-01-01

    Inflammation plays an important role in atherosclerosis. Given the increasing interest in using in-vivo imaging methods to study the physiology and treatment effects in atherosclerosis, noninvasive intraplaque inflammation quantitative method is needed. Dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) has been proposed and validated to quantitatively characterize atherosclerotic plaque inflammation. Recent studies have optimized the imaging protocol, pharmacokinetic modeling techniques. All of these technical advances further promoted DCE-MRI to clinical investigations in plaque risk assessment and therapeutic response monitor. Although larger clinical studies are still needed, DCE-MRI has been proven to be a promising tool to reveal more about intraplaque inflammation by in vivo quantitative inflammation imaging. PMID:24404443

  11. Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) in Preclinical Studies of Antivascular Treatments

    PubMed Central

    Nielsen, Thomas; Wittenborn, Thomas; Horsman, Michael R.

    2012-01-01

    Antivascular treatments can either be antiangiogenic or targeting established tumour vasculature. These treatments affect the tumour microvasculature and microenvironment but may not change clinical measures like tumour volume and growth. In research on antivascular treatments, information on the tumour vasculature is therefore essential. Preclinical research is often used for optimization of antivascular drugs alone or in combined treatments. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is an in vivo imaging method providing vascular information, which has become an important tool in both preclinical and clinical research. This review discusses common DCE-MRI imaging protocols and analysis methods and provides an overview of preclinical research on antivascular treatments utilizing DCE-MRI. PMID:24300371

  12. Oxygen-Enhanced MRI Accurately Identifies, Quantifies, and Maps Tumor Hypoxia in Preclinical Cancer Models.

    PubMed

    O'Connor, James P B; Boult, Jessica K R; Jamin, Yann; Babur, Muhammad; Finegan, Katherine G; Williams, Kaye J; Little, Ross A; Jackson, Alan; Parker, Geoff J M; Reynolds, Andrew R; Waterton, John C; Robinson, Simon P

    2016-02-15

    There is a clinical need for noninvasive biomarkers of tumor hypoxia for prognostic and predictive studies, radiotherapy planning, and therapy monitoring. Oxygen-enhanced MRI (OE-MRI) is an emerging imaging technique for quantifying the spatial distribution and extent of tumor oxygen delivery in vivo. In OE-MRI, the longitudinal relaxation rate of protons (?R1) changes in proportion to the concentration of molecular oxygen dissolved in plasma or interstitial tissue fluid. Therefore, well-oxygenated tissues show positive ?R1. We hypothesized that the fraction of tumor tissue refractory to oxygen challenge (lack of positive ?R1, termed "Oxy-R fraction") would be a robust biomarker of hypoxia in models with varying vascular and hypoxic features. Here, we demonstrate that OE-MRI signals are accurate, precise, and sensitive to changes in tumor pO2 in highly vascular 786-0 renal cancer xenografts. Furthermore, we show that Oxy-R fraction can quantify the hypoxic fraction in multiple models with differing hypoxic and vascular phenotypes, when used in combination with measurements of tumor perfusion. Finally, Oxy-R fraction can detect dynamic changes in hypoxia induced by the vasomodulator agent hydralazine. In contrast, more conventional biomarkers of hypoxia (derived from blood oxygenation-level dependent MRI and dynamic contrast-enhanced MRI) did not relate to tumor hypoxia consistently. Our results show that the Oxy-R fraction accurately quantifies tumor hypoxia noninvasively and is immediately translatable to the clinic. Cancer Res; 76(4); 787-95. 2015 AACR. PMID:26659574

  13. Novel kinetic texture features for breast lesion classification on dynamic contrast enhanced (DCE) MRI

    NASA Astrophysics Data System (ADS)

    Agner, Shannon C.; Soman, Salil; Libfeld, Edward; McDonald, Margie; Rosen, Mark A.; Schnall, Mitchell D.; Chin, Deanna; Nosher, John; Madabhushi, Anant

    2008-03-01

    Dynamic contrast enhanced (DCE) MRI has emerged as a promising new imaging modality for breast cancer screening. Currently, radiologists evaluate breast lesions based on qualitative description of lesion morphology and contrast uptake profiles. However, the subjectivity associated with qualitative description of breast lesions on DCE-MRI introduces a high degree of inter-observer variability. In addition, the high sensitivity of MRI results in poor specificity and thus a high rate of biopsies on benign lesions. Computer aided diagnosis (CAD) methods have been previously proposed for breast MRI, but research in the field is far from comprehensive. Most previous work has focused on either quantifying morphological attributes used by radiologists, characterizing lesion intensity profiles which reflect uptake of contrast dye, or characterizing lesion texture. While there has been much debate on the relative importance of the different classes of features (e.g., morphological, textural, and kinetic), comprehensive quantitative comparisons between the different lesion attributes have been rare. In addition, although kinetic signal enhancement curves may give insight into the underlying physiology of the lesion, signal intensity is susceptible to MRI acquisition artifacts such as bias field and intensity non-standardness. In this paper, we introduce a novel lesion feature that we call the kinetic texture feature, which we demonstrate to be superior compared to the lesion intensity profile dynamics. Our hypothesis is that since lesion intensity is susceptible to artifacts, lesion texture changes better reflect lesion class (benign or malignant). In this paper, we quantitatively demonstrate the superiority of kinetic texture features for lesion classification on 18 breast DCE-MRI studies compared to over 500 different morphological, kinetic intensity, and lesion texture features. In conjunction with linear and non-linear dimensionality reduction methods, a support vector machine (SVM) classifier yielded classification accuracy and positive predictive values of 78% and 86% with kinetic texture features compared to 78% and 73% with morphological features and 72% and 83% with textural features, respectively.

  14. Contrast-enhanced synthetic MRI for the detection of brain metastases

    PubMed Central

    Hori, Masaaki; Suzuki, Michimasa; Andica, Christina; Nakazawa, Misaki; Tsuruta, Kouhei; Takano, Nao; Sato, Shuji; Hamasaki, Nozomi; Yoshida, Mariko; Kumamaru, Kanako Kunishima; Ohtomo, Kuni; Aoki, Shigeki

    2016-01-01

    Background Synthetic magnetic resonance imaging (MRI), a technique that enables creation of various contrast-weighted images from a single MRI quantification scan, is a useful clinical tool. However, there are currently no reports examining the use of contrast-enhanced synthetic MRI for detecting brain metastases. Purpose To assess whether contrast-enhanced synthetic MRI is suitable for detecting brain metastases. Material and Methods Ten patients with a combined total of 167 brain metastases who underwent quantitative MRI and conventional T1-weighted inversion recovery fast spin-echo (conventional T1IR) MRI before and after administration of a contrast agent were included in the study. Synthetic T1IR and T1-weighted (synthetic T1W) images were produced after parameter quantification. Lesion-to-white matter contrast and contrast-to-noise ratio were calculated for each image. The number of visible lesions in each image was determined by two neuroradiologists. Results The mean lesion-to-white matter contrast and mean contrast-to-noise ratio of the synthetic T1IR images were significantly higher than those of the synthetic T1W (P < 0.001 and P < 0.001, respectively) and conventional T1IR (P = 0.04 and P = 0.002, respectively) images. Totals of 130 and 124 metastases were detected in the synthetic T1IR images by the first and second radiologists, respectively. The corresponding numbers were 91 and 85 in the synthetic T1W images and 119 and 119 in the conventional T1IR images. Statistical significance was not found among detected numbers of lesions. Conclusion Synthetic T1IR imaging created better contrast compared with synthetic T1W or conventional T1IR imaging. The ability to detect brain metastases was comparable among these imaging. PMID:26962461

  15. Efficient compressed sensing SENSE parallel MRI reconstruction with joint sparsity promotion and mutual incoherence enhancement.

    PubMed

    Il Yong Chun; Adcock, Ben; Talavage, Thomas M

    2014-01-01

    Magnetic resonance imaging (MRI) is considered a key modality for the future as it offers several advantages, including the use of non-ionizing radiation and having no known side effects on the human body, and has recently begun to serve as a key component of multi-modal neuroimaging. However, two major intrinsic problems exist: slow acquisition and intrusive acoustic noise. Parallel MRI (pMRI) techniques accelerate acquisition by reducing the duration and coverage of conventional gradient encoding. The under-sampled k-space data is detected with several receiver coils surrounding the object, using distinct spatial encoding information for each coil element to reconstruct the image. However, this scanning remains slow compared to typical clinical imaging (e.g. X-ray CT). Compressed Sensing (CS), a sampling theory based on random sub-sampling, has potential to further reduce the sampling used in pMRI, accelerating acquisition further. In this work, we propose a new CS SENSE pMRI reconstruction model promoting joint sparsity across channels and enhancing mutual incoherence to improve reconstruction accuracy from limited k-space data. For fast image reconstruction and fair comparisons, all reconstructions are computed with split-Bregman and variable splitting techniques. Numerical results show that, with the introduced methods, reconstruction performance can be crucially improved with limited amount of k-space data. PMID:25570479

  16. Perceptual enhancement of arteriovenous malformation in MRI angiography displays

    NASA Astrophysics Data System (ADS)

    Abhari, Kamyar; Baxter, John S. H.; Eagleson, Roy; Peters, Terry; de Ribaupierre, Sandrine

    2012-02-01

    The importance of presenting medical images in an intuitive and usable manner during a procedure is essential. However, most medical visualization interfaces, particularly those designed for minimally-invasive surgery, suffer from a number of issues as a consequence of disregarding the human perceptual, cognitive, and motor system's limitations. This matter is even more prominent when human visual system is overlooked during the design cycle. One example is the visualization of the neuro-vascular structures in MR angiography (MRA) images. This study investigates perceptual performance in the usability of a display to visualize blood vessels in MRA volumes using a contour enhancement technique. Our results show that when contours are enhanced, our participants, in general, can perform faster with higher level of accuracy when judging the connectivity of different vessels. One clinical outcome of such perceptual enhancement is improvement of spatial reasoning needed for planning complex neuro-vascular operations such as treating Arteriovenous Malformations (AVMs). The success of an AVM intervention greatly depends on fully understanding the anatomy of vascular structures. However, poor visualization of pre-operative MRA images makes the planning of such a treatment quite challenging.

  17. Dynamic Contrast-Enhanced MRI of Cervical Cancers: Temporal Percentile Screening of Contrast Enhancement Identifies Parameters for Prediction of Chemoradioresistance

    SciTech Connect

    Andersen, Erlend K.F.; Hole, Knut Hakon; Lund, Kjersti V.; Sundfor, Kolbein; Kristensen, Gunnar B.; Lyng, Heidi; Malinen, Eirik

    2012-03-01

    Purpose: To systematically screen the tumor contrast enhancement of locally advanced cervical cancers to assess the prognostic value of two descriptive parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Methods and Materials: This study included a prospectively collected cohort of 81 patients who underwent DCE-MRI with gadopentetate dimeglumine before chemoradiotherapy. The following descriptive DCE-MRI parameters were extracted voxel by voxel and presented as histograms for each time point in the dynamic series: normalized relative signal increase (nRSI) and normalized area under the curve (nAUC). The first to 100th percentiles of the histograms were included in a log-rank survival test, resulting in p value and relative risk maps of all percentile-time intervals for each DCE-MRI parameter. The maps were used to evaluate the robustness of the individual percentile-time pairs and to construct prognostic parameters. Clinical endpoints were locoregional control and progression-free survival. The study was approved by the institutional ethics committee. Results: The p value maps of nRSI and nAUC showed a large continuous region of percentile-time pairs that were significantly associated with locoregional control (p < 0.05). These parameters had prognostic impact independent of tumor stage, volume, and lymph node status on multivariate analysis. Only a small percentile-time interval of nRSI was associated with progression-free survival. Conclusions: The percentile-time screening identified DCE-MRI parameters that predict long-term locoregional control after chemoradiotherapy of cervical cancer.

  18. Motion compensated generalized reconstruction for free-breathing dynamic contrast-enhanced MRI.

    PubMed

    Filipovic, M; Vuissoz, P-A; Codreanu, A; Claudon, M; Felblinger, J

    2011-03-01

    The analysis of abdominal and thoracic dynamic contrast-enhanced MRI is often impaired by artifacts and misregistration caused by physiological motion. Breath-hold is too short to cover long acquisitions. A novel multipurpose reconstruction technique, entitled dynamic contrast-enhanced generalized reconstruction by inversion of coupled systems, is presented. It performs respiratory motion compensation in terms of both motion artefact correction and registration. It comprises motion modeling and contrast-change modeling. The method feeds on physiological signals and x-f space properties of dynamic series to invert a coupled system of linear equations. The unknowns solved for represent the parameters for a linear nonrigid motion model and the parameters for a linear contrast-change model based on B-splines. Performance is demonstrated on myocardial perfusion imaging, on six simulated data sets and six clinical exams. The main purpose consists in removing motion-induced errors from time-intensity curves, thus improving curve analysis and postprocessing in general. This method alleviates postprocessing difficulties in dynamic contrast-enhanced MRI and opens new possibilities for dynamic contrast-enhanced MRI analysis. PMID:20882640

  19. Immobilized Contrast Enhanced (ICE) MRI: Gadolinium-based long-term MR Contrast Enhancement of the Vein Graft Vessel Wall*

    PubMed Central

    Mitsouras, Dimitris; Vemula, Praveen Kumar; Yu, Peng; Tao, Ming; Nguyen, Binh T.; Campagna, Christina M.; Karp, Jeffrey M.; Mulkern, Robert V.; Ozaki, C. Keith; Rybicki, Frank J.

    2010-01-01

    An implantable MR contrast agent that can be covalently immobilized on tissue during surgery has been developed. The rationale is that a durable increase in tissue contrast using an implantable contrast agent can enhance post-surgical tissue differentiation using MRI. For small vessel (e.g., vein graft) MRI, the direct benefit of such permanent labeling of the vessel wall by modification of its relaxation properties is to achieve more efficient imaging. This efficiency can be realized as either increased contrast leading to more accurate delineation of vessel wall and lesion tissue boundaries, or, faster imaging without penalizing contrast-to-noise ratio, or a combination thereof. We demonstrate, for the first time, stable long-term MRI enhancement using such an exogenous contrast mechanism based on immobilizing a modified Gd-DTPA complex on a human vein using a covalent amide bond. Signal enhancement due to the covalently immobilized contrast agent is demonstrated for excised human vein specimens imaged at 3T, and its long-term stability is demonstrated during a 4-month incubation period. PMID:20859994

  20. Intraoperative detection of glioma invasion beyond MRI enhancement with Raman spectroscopy in humans

    NASA Astrophysics Data System (ADS)

    Jermyn, Michael; Mok, Kelvin; Mercier, Jeanne; Desroches, Joannie; Pichette, Julien; Saint-Arnaud, Karl; Guiot, Marie-Christine; Petrecca, Kevin; Leblond, Frédéric

    2015-03-01

    Cancer tissue is frequently impossible to distinguish from normal brain during surgery. Gliomas are a class of brain cancer which invade into the normal brain. If left unresected, these invasive cancer cells are the source of glioma recurrence. Moreover, these invasion areas do not show up on standard-of-care pre-operative Magnetic Resonance Imaging (MRI). This inability to fully visualize invasive brain cancers results in subtotal surgical resections, negatively impacting patient survival. To address this issue, we have demonstrated the efficacy of single-point in vivo Raman spectroscopy using a contact hand-held fiber optic probe for rapid detection of cancer invasion in 8 patients with low and high grade gliomas. Using a supervised machine learning algorithm to analyze the Raman spectra obtained in vivo, we were able to distinguish normal brain from the presence of cancer cells with sensitivity and specificity greater than 90%. Moreover, by correlating these results with pre-operative MRI we demonstrate the ability to detect low density cancer invasion up to 1.5cm beyond the cancer extent visible using MRI. This represents the potential for significant improvements in progression-free and overall patient survival, by identifying previously undetectable residual cancer cell populations and preventing the resection of normal brain tissue. While the importance of maximizing the volume of tumor resection is important for all grades of gliomas, the impact for low grade gliomas can be dramatic because surgery can even be curative. This convenient technology can rapidly classify cancer invasion in real-time, making it ideal for intraoperative use in brain tumor resection.

  1. Assessment of blood–brain barrier disruption using dynamic contrast-enhanced MRI. A systematic review

    PubMed Central

    Heye, Anna K.; Culling, Ross D.; Valdés Hernández, Maria del C.; Thrippleton, Michael J.; Wardlaw, Joanna M.

    2014-01-01

    There is increasing recognition of the importance of blood–brain barrier (BBB) disruption in aging, dementia, stroke and multiple sclerosis in addition to more commonly-studied pathologies such as tumors. Dynamic contrast-enhanced MRI (DCE-MRI) is a method for studying BBB disruption in vivo. We review pathologies studied, scanning protocols and data analysis procedures to determine the range of available methods and their suitability to different pathologies. We systematically review the existing literature up to February 2014, seeking studies that assessed BBB integrity using T1-weighted DCE-MRI techniques in animals and humans in normal or abnormal brain tissues. The literature search provided 70 studies that were eligible for inclusion, involving 417 animals and 1564 human subjects in total. The pathologies most studied are intracranial neoplasms and acute ischemic strokes. There are large variations in the type of DCE-MRI sequence, the imaging protocols and the contrast agents used. Moreover, studies use a variety of different methods for data analysis, mainly based on model-free measurements and on the Patlak and Tofts models. Consequently, estimated KTrans values varied widely. In conclusion, DCE-MRI is shown to provide valuable information in a large variety of applications, ranging from common applications, such as grading of primary brain tumors, to more recent applications, such as assessment of subtle BBB dysfunction in Alzheimer's disease. Further research is required in order to establish consensus-based recommendations for data acquisition and analysis and, hence, improve inter-study comparability and promote wider use of DCE-MRI. PMID:25379439

  2. Multifunctional nanoparticle platforms for in vivo MRI enhancement and photodynamic therapy of a rat brain cancer

    NASA Astrophysics Data System (ADS)

    Kopelman, Raoul; Lee Koo, Yong-Eun; Philbert, Martin; Moffat, Bradford A.; Ramachandra Reddy, G.; McConville, Patrick; Hall, Daniel E.; Chenevert, Thomas L.; Bhojani, Mahaveer Swaroop; Buck, Sarah M.; Rehemtulla, Alnawaz; Ross, Brian D.

    2005-05-01

    A paradigm for brain cancer detection, treatment, and monitoring is established. Multifunctional biomedical nanoparticles (30-60 nm) containing photosensitizer externally deliver reactive oxygen species (ROS) to cancer cells while simultaneously enhancing magnetic resonance imaging (MRI) contrast providing real-time tumor kill measurement. Plasma residence time control and specific cell targeting are achieved. A 5 min treatment in rats halted and even reversed in vivo tumor growth after 3-4 days post-treatment.

  3. Distinguishing species.

    PubMed

    Mller, Tobias; Philippi, Nicole; Dandekar, Thomas; Schultz, Jrg; Wolf, Matthias

    2007-09-01

    Given two organisms, how can one distinguish whether they belong to the same species or not? This might be straightforward for two divergent organisms, but can be extremely difficult and laborious for closely related ones. A molecular marker giving a clear distinction would therefore be of immense benefit. The internal transcribed spacer 2 (ITS2) has been widely used for low-level phylogenetic analyses. Case studies revealed that a compensatory base change (CBC) in the helix II or helix III ITS2 secondary structure between two organisms correlated with sexual incompatibility. We analyzed more than 1300 closely related species to test whether this correlation is generally applicable. In 93%, where a CBC was found between organisms classified within the same genus, they belong to different species. Thus, a CBC in an ITS2 sequence-structure alignment is a sufficient condition to distinguish even closely related species. PMID:17652131

  4. Tryptophan PET predicts spatial and temporal patterns of post-treatment glioblastoma progression detected by contrast-enhanced MRI.

    PubMed

    Bosnyk, Edit; Kamson, David O; Robinette, Natasha L; Barger, Geoffrey R; Mittal, Sandeep; Juhsz, Csaba

    2016-01-01

    Amino acid PET is increasingly utilized for the detection of recurrent gliomas. Increased amino acid uptake is often observed outside the contrast-enhancing brain tumor mass. In this study, we evaluated if non-enhancing PET+ regions could predict spatial and temporal patterns of subsequent MRI progression in previously treated glioblastomas. Twelve patients with a contrast-enhancing area suspicious for glioblastoma recurrence on MRI underwent PET scanning with the amino acid radiotracer alpha-[(11)C]-methyl-L-tryptophan (AMT). Brain regions showing increased AMT uptake in and outside the contrast-enhancing volume were objectively delineated to include high uptake consistent with glioma (as defined by previous studies). Volume and tracer uptake of such non-enhancing PET+ regions were compared to spatial patterns and timing of subsequent progression of the contrast-enhancing lesion, as defined by serial surveillance MRI. Non-enhancing PET+ volumes varied widely across patients and extended up to 24mm from the edge of MRI contrast enhancement. In ten patients with clear progression of the contrast-enhancing lesion, the non-enhancing PET+ volumes predicted the location of new enhancement, which extended beyond the PET+ brain tissue in six. In two patients, with no PET+ area beyond the initial contrast enhancement, MRI remained stable. There was a negative correlation between AMT uptake in non-enhancing brain and time to subsequent progression (r=-0.77, p=0.003). Amino acid PET imaging could complement MRI not only for detecting glioma recurrence but also predicting the location and timing of subsequent tumor progression. This could support decisions for surgical intervention or other targeted therapies for recurrent gliomas. PMID:26514361

  5. A corrole nanobiologic elicits tissue-activated MRI contrast enhancement and tumor-targeted toxicity.

    PubMed

    Sims, Jessica D; Hwang, Jae Youn; Wagner, Shawn; Alonso-Valenteen, Felix; Hanson, Chris; Taguiam, Jan Michael; Polo, Richard; Harutyunyan, Ira; Karapetyan, Gevorg; Sorasaenee, Karn; Ibrahim, Ahmed; Marban, Eduardo; Moats, Rex; Gray, Harry B; Gross, Zeev; Medina-Kauwe, Lali K

    2015-11-10

    Water-soluble corroles with inherent fluorescence can form stable self-assemblies with tumor-targeted cell penetration proteins, and have been explored as agents for optical imaging and photosensitization of tumors in pre-clinical studies. However, the limited tissue-depth of excitation wavelengths limits their clinical applicability. To examine their utility in more clinically-relevant imaging and therapeutic modalities, here we have explored the use of corroles as contrast enhancing agents for magnetic resonance imaging (MRI), and evaluated their potential for tumor-selective delivery when encapsulated by a tumor-targeted polypeptide. We have found that a manganese-metallated corrole exhibits significant T1 relaxation shortening and MRI contrast enhancement that is blocked by particle formation in solution but yields considerable MRI contrast after tissue uptake. Cell entry but not low pH enables this. Additionally, the corrole elicited tumor-toxicity through the loss of mitochondrial membrane potential and cytoskeletal breakdown when delivered by the targeted polypeptide. The protein-corrole particle (which we call HerMn) exhibited improved therapeutic efficacy compared to current targeted therapies used in the clinic. Taken together with its tumor-preferential biodistribution, our findings indicate that HerMn can facilitate tumor-targeted toxicity after systemic delivery and tumor-selective MR imaging activatable by internalization. PMID:26334483

  6. Added value of diffusion-weighted MRI in detection of cervical cancer recurrence: comparison with morphologic and dynamic contrast-enhanced MRI sequences

    PubMed Central

    Lucas, Rita; Dias, João Lopes; Cunha, Teresa Margarida

    2015-01-01

    PURPOSE We aimed to evaluate the added value of diffusion-weighted imaging (DWI) to standard magnetic resonance imaging (MRI) for detecting post-treatment cervical cancer recurrence. The detection accuracy of T2-weighted (T2W) images was compared with that of T2W MRI combined with either dynamic contrast-enhanced (DCE) MRI or DWI. METHODS Thirty-eight women with clinically suspected uterine cervical cancer recurrence more than six months after treatment completion were examined with 1.5 Tesla MRI including T2W, DCE, and DWI sequences. Disease was confirmed histologically and correlated with MRI findings. The diagnostic performance of T2W imaging and its combination with either DCE or DWI were analyzed. Sensitivity, positive predictive value, and accuracy were calculated. RESULTS Thirty-six women had histologically proven recurrence. The accuracy for recurrence detection was 80% with T2W/DCE MRI and 92.1% with T2W/DWI. The addition of DCE sequences did not significantly improve the diagnostic ability of T2W imaging, and this sequence combination misclassified two patients as falsely positive and seven as falsely negative. The T2W/DWI combination revealed a positive predictive value of 100% and only three false negatives. CONCLUSION The addition of DWI to T2W sequences considerably improved the diagnostic ability of MRI. Our results support the inclusion of DWI in the initial MRI protocol for the detection of cervical cancer recurrence, leaving DCE sequences as an option for uncertain cases. PMID:26200480

  7. Enhanced brain connectivity in math-gifted adolescents: An fMRI study using mental rotation.

    PubMed

    Prescott, James; Gavrilescu, Maria; Cunnington, Ross; O'Boyle, Michael W; Egan, Gary F

    2010-12-01

    Mathematical giftedness is a form of intelligence related to enhanced mathematical reasoning that can be tested using a variety of numerical and spatial tasks. A number of neurobiological mechanisms related to exceptional mathematical reasoning ability have been postulated, including enhanced brain connectivity. We aimed to further investigate this possibility by comparing a group of mathematically gifted adolescents with an average math ability control group performing mental rotation of complex three-dimensional block figures. Functional magnetic resonance imaging (fMRI) data were collected and differences in intrahemispheric and interhemispheric connectivity between the groups were assessed using structural equation modeling (SEM). The math-gifted showed heightened intrahemispheric frontoparietal connectivity, as well as enhanced interhemispheric frontal connectivity between the dorsolateral prefrontal and premotor cortex. These enhanced connectivity patterns are consistent with previous studies linking increased activation of the frontal and parietal regions with high fluid intelligence, and may be a unique neural characteristic of the mathematically gifted brain. PMID:24168381

  8. Description of focal liver lesions with Gd-EOB-DTPA enhanced MRI

    PubMed Central

    CARAIANI, COSMIN-NICOLAE; DAN, MARIAN; FENESAN, DIANA-IOANA; BADEA, RADU

    2015-01-01

    Imaging procedures play a fundamental role in the therapeutic management of focal liver lesions. The goals of imaging are to detect and correctly characterize focal liver lesions. This review highlights the performances of newer, liver-specific, contrast media in the diagnosis of focal liver lesions, particularly Gd-EOB-DTPA (Primovist), the most frequently used liver specific contrast media. It has been shown, in different papers, that Gd-EOB-DTPA has better performances compared to either triphasic contrast enhanced computed tomography or dynamic MRI in both detection and characterization of hepatocellular carcinoma on the cirrhotic liver. Therefore liver MRI with Primovist is considered, in many centers, the state-of-the-art imaging examination of the liver before surgery or liver transplantation. Gd-EOB-DTPA is also useful in the differential diagnosis of benign hypervascular focal liver lesions such as adenomas or focal nodular hyperplasias. PMID:26733231

  9. Use of dynamic contrast-enhanced MRI to measure subtle blood-brain barrier abnormalities.

    PubMed

    Armitage, Paul A; Farrall, Andrew J; Carpenter, Trevor K; Doubal, Fergus N; Wardlaw, Joanna M

    2011-04-01

    There is growing interest in investigating the role of subtle changes in blood-brain barrier (BBB) function in common neurological disorders and the possible use of imaging techniques to assess these abnormalities. Some studies have used dynamic contrast-enhanced MR imaging (DCE-MRI) and these have demonstrated much smaller signal changes than obtained from more traditional applications of the technique, such as in intracranial tumors and multiple sclerosis. In this work, preliminary results are presented from a DCE-MRI study of patients with mild stroke classified according to the extent of visible underlying white matter abnormalities. These data are used to estimate typical signal enhancement profiles in different tissue types and by degrees of white matter abnormality. The effect of scanner noise, drift and different intrinsic tissue properties on signal enhancement data is also investigated and the likely implications for interpreting the enhancement profiles are discussed. No significant differences in average signal enhancement or contrast agent concentration were observed between patients with different degrees of white matter abnormality, although there was a trend towards greater signal enhancement with more abnormal white matter. Furthermore, the results suggest that many of the factors considered introduce uncertainty of a similar magnitude to expected effect sizes, making it unclear whether differences in signal enhancement are truly reflective of an underlying BBB abnormality or due to an unrelated effect. As the ultimate aim is to achieve a reliable quantification of BBB function in subtle disorders, this study highlights the factors which may influence signal enhancement and suggests that further work is required to address the challenging problems of quantifying contrast agent concentration in healthy and diseased living human tissue and of establishing a suitable model to enable quantification of relevant physiological parameters. Meanwhile, it is essential that future studies use an appropriate control group to minimize these influences. PMID:21030178

  10. The dynamic of FUS-induced BBB Opening in Mouse Brain assessed by contrast enhanced MRI

    NASA Astrophysics Data System (ADS)

    Jenne, Jürgen W.; Krafft, Axel J.; Maier, Florian; Krause, Marie N.; Kleber, Susanne; Huber, Peter E.; Martin-Villalba, Ana; Bock, Michael

    2010-03-01

    Focused ultrasound (FUS) in combination with the administration of gas-filled microbubbles, can induce a localized and reversible opening of the blood brain barrier (BBB). Contrast enhanced magnetic resonance imaging (MRI) has been demonstrated as a precise tool to monitor such a local BBB disruption. However, the opening/closing mechanisms of the BBB with FUS are still largely unknown. In this ongoing project, we study the BBB opening dynamics in mouse brain comparing an interstitial and an intravascular MR contrast agent (CA). FUS in mouse brain was performed with an MRI compatible treatment setup (1.7 MHz fix-focus US transducer, f' = 68 mm, NA = 0.44; focus: 8.1 mm length; O/ = 1.1 mm) in a 1.5 T whole body MRI system. For BBB opening, forty 10 ms-long FUS-pulses were applied at a repetition rate of 1 Hz at 1 MPa. The i.v. administration of the micro bubbles (50 μl SonoVue®) was started simultaneously with FUS exposure. To analyze the BBB opening process, short-term and long-term MRI signal dynamics of the interstitial MR contrast agent Magnevist® and the intravascular CA Vasovist® (Bayer-Schering) were studied. To assess short-term signal dynamics, T1-weighted inversion recovery turbo FLASH images (1s) were repeatedly acquired. Repeated 3D FLASH acquisitions (90 s) were used to assess long-term MRI signal dynamics. The short-term MRI signal enhancements showed comparable time constants for both types of MR contrast agents: 1.1 s (interstitial) vs. 0.8 s (intravascular). This time constant may serve as a time constant of the BBB opening process with the given FUS exposure parameters. For the long-term signal dynamics the intravascular CA (62±10 min) showed a fife times greater time constant as the interstitial contrast agent (12±10 min). This might be explained by the high molecular weight (˜60 kDa) of the intravascular Vasovist due to its reversible binding to blood serum albumin resulting in a prolonged half-life in the blood stream compared to the interstitial CA. As the intravascular CA offers a much longer time window for therapy assessment, FUS-BBB therapy control with an intravascular CA might be favorable.

  11. Quantification of fibrosis in infarcted swine hearts by ex vivo late gadolinium-enhancement and diffusion-weighted MRI methods

    NASA Astrophysics Data System (ADS)

    Pop, Mihaela; Ghugre, Nilesh R.; Ramanan, Venkat; Morikawa, Lily; Stanisz, Greg; Dick, Alexander J.; Wright, Graham A.

    2013-08-01

    Many have speculated that MRI signal characteristics can be used to identify regions of heterogeneous infarct associated with an arrhythmogenic substrate; however, direct evidence of this relationship is limited. The aim of this study was to demonstrate the remodelling characteristics of fibrosis by means of histology and high-resolution MR imaging. For this purpose, we performed whole-mount histology in heart samples (n = 9) collected from five swine at six weeks post-infarction and compared the extent of fibrosis in the infarcted areas delineated in these histological images with that obtained ex vivo by MRI using late gadolinium-enhancement (LGE) and diffusion-weighted imaging (DWI) methods. All MR images were obtained at a submillimetre resolution (i.e., voxel size of 0.6×0.6×1.2 mm3). Specifically, in the histology images, we differentiated moderate fibrosis (consisting of a mixture of viable and non-viable myocytes, known as border zone, BZ) from severe fibrosis (i.e., the dense scar). Correspondingly, tissue heterogeneities in the MR images were categorized by a Gaussian mixture model into healthy, BZ and scar. Our results showed that (a) both MRI methods were capable of qualitatively distinguishing sharp edges between dense scar and healthy tissue from regions of heterogeneous BZ; (b) the BZ and dense scar areas had intermediate-to-high increased values of signal intensity in the LGE images and of apparent diffusion coefficient in the DWI, respectively. In addition, as demonstrated by the Picrosirius Red and immunohistochemistry stains, the viable bundles in the BZ were clearly separated by thin collagen strands and had reduced expression of Cx43, whereas the core scar was composed of dense fibrosis. A quantitative analysis demonstrated that the comparison between BZ/scar extent in LGE and DWI to the corresponding areas identified in histology yielded very good correlations (i.e., for the scar identified by LGE, R2 was 0.96 compared to R2 = 0.93 for the scar identified in ADC maps, whereas the BZ had R2 = 0.95 for the correlation between LGE and histology compared to R2 = 0.91 obtained for ADC). This novel study represents an intermediate step in translating such research to the in vivo stages, as well as in establishing the best and most accurate MR method to help identify arrhythmia substrate in patients with structural heart disease.

  12. Dynamic contrast enhanced T1 MRI perfusion differentiates pseudoprogression from recurrent glioblastoma

    PubMed Central

    Thomas, Alissa A.; Arevalo-Perez, Julio; Kaley, Thomas; Lyo, John; Peck, Kyung K.; Shi, Weiji; Zhang, Zhigang

    2016-01-01

    Pseudoprogression may present as transient new or increasing enhancing lesions that mimic recurrent tumors in treated glioblastoma. The purpose of this study was to examine the utility of dynamic contrast enhanced T1 magnetic resonance imaging (DCE MRI) in differentiating between pseudoprogression and tumor progression and devise a cut-off value sensitive for pseudoprogression. We retrospectively examined 37 patients with glioblastoma treated with radiation and temozolomide after surgical resection that then developed new or increasing enhancing lesion(s) indeterminate for pseudoprogression versus progression. Volumetric plasma volume (Vp) and time-dependent leakage constant (Ktrans) maps were measured for the enhancing lesion and the mean and ninetieth percentile histogram values recorded. Lesion outcome was determined by clinical follow up with pseudoprogression defined as stable disease not requiring new treatment. Statistical analysis was performed with Wilcoxon rank-sum tests. Patients with pseudoprogression (n = 13) had Vp (mean) = 2.4 and Vp (90 %tile) = 3.2; and Ktrans (mean) = 3.5 and Ktrans (90 %tile) = 4.2. Patients with tumor progression (n = 24) had Vp (mean) = 5.3 and Vp (90 %tile) = 6.6; and Ktrans (mean) = 7.4 and Ktrans (90 %tile) = 9.1. Compared with tumor progression, pseudoprogression demonstrated lower Vp perfusion values (p = 0.0002) with a Vp (mean) cutoff <3.7 yielding 85 % sensitivity and 79 % specificity for pseudoprogression. Ktrans (mean) of >3.6 had a 69 % sensitivity and 79 % specificity for disease progression. DCE MRI shows lower plasma volume and time dependent leakage constant values in pseudoprogression than in tumor progression. A cut-off value with high sensitivity for pseudoprogression can be applied to aid in interpretation of DCE MRI. PMID:26275367

  13. Simultaneous tDCS-fMRI Identifies Resting State Networks Correlated with Visual Search Enhancement

    PubMed Central

    Callan, Daniel E.; Falcone, Brian; Wada, Atsushi; Parasuraman, Raja

    2016-01-01

    This study uses simultaneous transcranial direct current stimulation (tDCS) and functional MRI (fMRI) to investigate tDCS modulation of resting state activity and connectivity that underlies enhancement in behavioral performance. The experiment consisted of three sessions within the fMRI scanner in which participants conducted a visual search task: Session 1: Pre-training (no performance feedback), Session 2: Training (performance feedback given), Session 3: Post-training (no performance feedback). Resting state activity was recorded during the last 5 min of each session. During the 2nd session one group of participants underwent 1 mA tDCS stimulation and another underwent sham stimulation over the right posterior parietal cortex. Resting state spontaneous activity, as measured by fractional amplitude of low frequency fluctuations (fALFF), for session 2 showed significant differences between the tDCS stim and sham groups in the precuneus. Resting state functional connectivity from the precuneus to the substantia nigra, a subcortical dopaminergic region, was found to correlate with future improvement in visual search task performance for the stim over the sham group during active stimulation in session 2. The after-effect of stimulation on resting state functional connectivity was measured following a post-training experimental session (session 3). The left cerebellum Lobule VIIa Crus I showed performance related enhancement in resting state functional connectivity for the tDCS stim over the sham group. The ability to determine the relationship that the relative strength of resting state functional connectivity for an individual undergoing tDCS has on future enhancement in behavioral performance has wide ranging implications for neuroergonomic as well as therapeutic, and rehabilitative applications. PMID:27014014

  14. Brain-wide pathway for waste clearance captured by contrast-enhanced MRI

    PubMed Central

    Iliff, Jeffrey J.; Lee, Hedok; Yu, Mei; Feng, Tian; Logan, Jean; Nedergaard, Maiken; Benveniste, Helene

    2013-01-01

    The glymphatic system is a recently defined brain-wide paravascular pathway for cerebrospinal fluid (CSF) and interstitial fluid (ISF) exchange that facilitates efficient clearance of solutes and waste from the brain. CSF enters the brain along para-arterial channels to exchange with ISF, which is in turn cleared from the brain along para-venous pathways. Because soluble amyloid ? clearance depends on glymphatic pathway function, we proposed that failure of this clearance system contributes to amyloid plaque deposition and Alzheimers disease progression. Here we provide proof of concept that glymphatic pathway function can be measured using a clinically relevant imaging technique. Dynamic contrast-enhanced MRI was used to visualize CSF-ISF exchange across the rat brain following intrathecal paramagnetic contrast agent administration. Key features of glymphatic pathway function were confirmed, including visualization of para-arterial CSF influx and molecular size-dependent CSF-ISF exchange. Whole-brain imaging allowed the identification of two key influx nodes at the pituitary and pineal gland recesses, while dynamic MRI permitted the definition of simple kinetic parameters to characterize glymphatic CSF-ISF exchange and solute clearance from the brain. We propose that this MRI approach may provide the basis for a wholly new strategy to evaluate Alzheimers disease susceptibility and progression in the live human brain. PMID:23434588

  15. DCE@urLAB: a dynamic contrast-enhanced MRI pharmacokinetic analysis tool for preclinical data

    PubMed Central

    2013-01-01

    Background DCE@urLAB is a software application for analysis of dynamic contrast-enhanced magnetic resonance imaging data (DCE-MRI). The tool incorporates a friendly graphical user interface (GUI) to interactively select and analyze a region of interest (ROI) within the image set, taking into account the tissue concentration of the contrast agent (CA) and its effect on pixel intensity. Results Pixel-wise model-based quantitative parameters are estimated by fitting DCE-MRI data to several pharmacokinetic models using the Levenberg-Marquardt algorithm (LMA). DCE@urLAB also includes the semi-quantitative parametric and heuristic analysis approaches commonly used in practice. This software application has been programmed in the Interactive Data Language (IDL) and tested both with publicly available simulated data and preclinical studies from tumor-bearing mouse brains. Conclusions A user-friendly solution for applying pharmacokinetic and non-quantitative analysis DCE-MRI in preclinical studies has been implemented and tested. The proposed tool has been specially designed for easy selection of multi-pixel ROIs. A public release of DCE@urLAB, together with the open source code and sample datasets, is available at http://www.die.upm.es/im/archives/DCEurLAB/. PMID:24180558

  16. Dynamic-contrast-enhanced-MRI with extravasating contrast reagent: rat cerebral glioma blood volume determination.

    PubMed

    Li, Xin; Rooney, William D; Vrallyay, Csand G; Gahramanov, Seymur; Muldoon, Leslie L; Goodman, James A; Tagge, Ian J; Selzer, Audrey H; Pike, Martin M; Neuwelt, Edward A; Springer, Charles S

    2010-10-01

    The accurate mapping of the tumor blood volume (TBV) fraction (vb) is a highly desired imaging biometric goal. It is commonly thought that achieving this is difficult, if not impossible, when small molecule contrast reagents (CRs) are used for the T1-weighted (Dynamic-Contrast-Enhanced) DCE-MRI technique. This is because angiogenic malignant tumor vessels allow facile CR extravasation. Here, a three-site equilibrium water exchange model is applied to DCE-MRI data from the cerebrally-implanted rat brain U87 glioma, a tumor exhibiting rapid CR extravasation. Analyses of segments of the (and the entire) DCE data time-course with this "shutter-speed" pharmacokinetic model, which admits finite water exchange kinetics, allow TBV estimation from the first-pass segment. Pairwise parameter determinances were tested with grid searches of 2D parametric error surfaces. Tumor blood volume (vb), as well as ve (the extracellular, extravascular space volume fraction), and Ktrans (a CR extravasation rate measure) parametric maps are presented. The role of the Patlak Plot in DCE-MRI is also considered. PMID:20674422

  17. Dynamic-contrast-enhanced-MRI with extravasating contrast reagent: Rat cerebral glioma blood volume determination

    NASA Astrophysics Data System (ADS)

    Li, Xin; Rooney, William D.; Vrallyay, Csand G.; Gahramanov, Seymur; Muldoon, Leslie L.; Goodman, James A.; Tagge, Ian J.; Selzer, Audrey H.; Pike, Martin M.; Neuwelt, Edward A.; Springer, Charles S.

    2010-10-01

    The accurate mapping of the tumor blood volume (TBV) fraction ( vb) is a highly desired imaging biometric goal. It is commonly thought that achieving this is difficult, if not impossible, when small molecule contrast reagents (CRs) are used for the T1-weighted (Dynamic-Contrast-Enhanced) DCE-MRI technique. This is because angiogenic malignant tumor vessels allow facile CR extravasation. Here, a three-site equilibrium water exchange model is applied to DCE-MRI data from the cerebrally-implanted rat brain U87 glioma, a tumor exhibiting rapid CR extravasation. Analyses of segments of the (and the entire) DCE data time-course with this "shutter-speed" pharmacokinetic model, which admits finite water exchange kinetics, allow TBV estimation from the first-pass segment. Pairwise parameter determinances were tested with grid searches of 2D parametric error surfaces. Tumor blood volume ( vb), as well as ve (the extracellular, extravascular space volume fraction), and Ktrans (a CR extravasation rate measure) parametric maps are presented. The role of the Patlak Plot in DCE-MRI is also considered.

  18. Super-resolved enhancing and edge deghosting (SEED) for spatiotemporally encoded single-shot MRI.

    PubMed

    Chen, Lin; Li, Jing; Zhang, Miao; Cai, Shuhui; Zhang, Ting; Cai, Congbo; Chen, Zhong

    2015-07-01

    Spatiotemporally encoded (SPEN) single-shot MRI is an ultrafast MRI technique proposed recently, which utilizes quadratic rather than linear phase profile to extract the spatial information. Compared to the echo planar imaging (EPI), this technique has great advantages in resisting field inhomogeneity and chemical shift effects. Super-resolved (SR) reconstruction is adopted to compensate the inherent low resolution of SPEN images. Due to insufficient sampling rate, the SR image is challenged by aliasing artifacts and edge ghosts. The existing SR algorithms always compromise in spatial resolution to suppress these undesirable artifacts. In this paper, we proposed a novel SR algorithm termed super-resolved enhancing and edge deghosting (SEED). Different from artifacts suppression methods, our algorithm aims at exploiting the relationship between aliasing artifacts and real signal. Based on this relationship, the aliasing artifacts can be eliminated without spatial resolution loss. According to the trait of edge ghosts, finite differences and high-pass filter are employed to extract the prior knowledge of edge ghosts. By combining the prior knowledge with compressed sensing, our algorithm can efficiently reduce the edge ghosts. The robustness of SEED is demonstrated by experiments under various situations. The results indicate that the SEED can provide better spatial resolution compared to state-of-the-art SR reconstruction algorithms in SPEN MRI. Theoretical analysis and experimental results also show that the SR images reconstructed by SEED have better spatial resolution than the images obtained with conventional k-space encoding methods under similar experimental condition. PMID:25910683

  19. Combined Dynamic Contrast Enhanced Liver MRI and MRA Using Interleaved Variable Density Sampling

    PubMed Central

    Rahimi, Mahdi Salmani; Korosec, Frank R.; Wang, Kang; Holmes, James H.; Motosugi, Utaroh; Bannas, Peter; Reeder, Scott B.

    2014-01-01

    Purpose To develop and evaluate a method for volumetric contrast-enhanced MR imaging of the liver, with high spatial and temporal resolutions, for combined dynamic imaging and MR angiography using a single injection of contrast. Methods An interleaved variable density (IVD) undersampling pattern was implemented in combination with a real-time-triggered, time-resolved, dual-echo 3D spoiled gradient echo sequence. Parallel imaging autocalibration lines were acquired only once during the first time-frame. Imaging was performed in ten subjects with focal nodular hyperplasia (FNH) and compared with their clinical MRI. The angiographic phase of the proposed method was compared to a dedicated MR angiogram acquired during a second injection of contrast. Results A total of 21 FNH, 3 cavernous hemangiomas, and 109 arterial segments were visualized in 10 subjects. The temporally-resolved images depicted the characteristic arterial enhancement pattern of the lesions with a 4 s update rate. Images were graded as having significantly higher quality compared to the clinical MRI. Angiograms produced from the IVD method provided non-inferior diagnostic assessment compared to the dedicated MRA. Conclusion Using an undersampled IVD imaging method, we have demonstrated the feasibility of obtaining high spatial and temporal resolution dynamic contrast-enhanced imaging and simultaneous MRA of the liver. PMID:24639130

  20. Quantifying heterogeneity of lesion uptake in dynamic contrast enhanced MRI for breast cancer diagnosis

    NASA Astrophysics Data System (ADS)

    Karahaliou, A.; Vassiou, K.; Skiadopoulos, S.; Kanavou, T.; Yiakoumelos, A.; Costaridou, L.

    2009-07-01

    The current study investigates whether texture features extracted from lesion kinetics feature maps can be used for breast cancer diagnosis. Fifty five women with 57 breast lesions (27 benign, 30 malignant) were subjected to dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) on 1.5T system. A linear-slope model was fitted pixel-wise to a representative lesion slice time series and fitted parameters were used to create three kinetic maps (wash out, time to peak enhancement and peak enhancement). 28 grey level co-occurrence matrices features were extracted from each lesion kinetic map. The ability of texture features per map in discriminating malignant from benign lesions was investigated using a Probabilistic Neural Network classifier. Additional classification was performed by combining classification outputs of most discriminating feature subsets from the three maps, via majority voting. The combined scheme outperformed classification based on individual maps achieving area under Receiver Operating Characteristics curve 0.9600.029. Results suggest that heterogeneity of breast lesion kinetics, as quantified by texture analysis, may contribute to computer assisted tissue characterization in DCE-MRI.

  1. MRI contrast enhancement by Gd-DTPA-monoclonal antibody in 9L glioma rats.

    PubMed

    Matsumura, A; Shibata, Y; Nakagawa, K; Nose, T

    1994-01-01

    To achieve a tissue-specific enhancement in diagnosis of brain tumor, a magnetic resonance imaging (MRI) study was performed using conjugate of Gd-DTPA and monoclonal antibody (MoAb) against 9L glioma cells. Fisher 344 strain rats were used for this study. MoAb against 9L glioma cells was conjugated with Gd-DTPA according to the method of Hnatowich et al. (1983) and used for the MRI study. The gadolinium (Gd) concentration in the Gd-MoAb injected to the rats was 0.01-0.03 mmol/kg. The enhancement effect increased gradually and persisted for 24 hours after the injection. This was longer than Gd-DTPA, which showed a peak of enhancement effect within 30 minutes after injection and was washed out within 120 min. This result was compatible with scintigraphy studies using 125I labeled anti 9L monoclonal antibody, in which the accumulation of the 125I antibody increased at 24, 48 and 72 hours after the injection. By using tumor-specific contrast agents such as Gd-MoAb, it may be possible to differentiate among tumor, perifocal edema and radiation injury. PMID:7976589

  2. Quantitative MRI of colonic mural enhancement: segmental differences exist in endoscopically proven normal colon

    PubMed Central

    Punwani, S; Hafeez, R; Bainbridge, A; Boulos, P; Halligan, S; Bloom, S; Taylor, S A

    2012-01-01

    Objectives Abnormal contrast enhancement on MRI is advocated as a biomarker for inflammation in colitis, although the enhancement kinetics of normal colon are poorly described. Our purpose was to quantitatively assess mural enhancement in normal colon and test for intersegmental differences. Methods Eight patients without prior history of inflammatory bowel disease underwent standard MRI colonography followed by normal same-day colonoscopy. Acquired sequences included a volumetric interpolated breath-hold examination (VIBE) to encompass the whole colonic volume, performed at 5°, 10° and 35° flip angles for T1 quantitation and then at a fixed 35° flip angle three times prior to and every 30 s following intravenous gadoterate meglumine for 220 s. Ascending colon, descending colon and rectal R1 (1/T1) was plotted against time. Mean pre-contrast R1, initial change of R1 (ΔR1), early and late “plateau phase” enhancement and the area under the R1–time (AUC–R1) curve were compared between segments using the Student's paired t-test. Results There was no significant difference of pre-contrast R1 between segments (p=0.49 to 0.62). ΔR1 was higher for ascending colon compared with descending colon (0.0023±0.0012 ms−1 vs 0.0010±0.0011 ms−1, p=0.03). There was no significant difference for early or late plateau phase R1 between colonic segments (p=0.08 to 1.00). AUC–R1 was greater for ascending than descending colon (0.54±0.19 vs 0.30±0.14, p=0.03). Conclusions Intersegmental differences in colonic enhancement are present and should be considered when interpreting differential segmental enhancement. PMID:22919009

  3. Water-dispersible ascorbic-acid-coated magnetite nanoparticles for contrast enhancement in MRI

    NASA Astrophysics Data System (ADS)

    Sreeja, V.; Jayaprabha, K. N.; Joy, P. A.

    2015-04-01

    Superparamagnetic iron oxide nanoparticles of size ~5 nm surface functionalized with ascorbic acid (vitamin C) form a stable dispersion in water with a hydrodynamic size of ~30 nm. The anti-oxidant property of ascorbic acid is retained after capping, as evidenced from the capability of converting methylene blue to its reduced leuco form. NMR relaxivity studies show that the ascorbic-acid-coated superparamagnetic iron oxide aqueous nanofluid is suitable as a contrast enhancement agent for MRI applications, coupled with the excellent biocompatibility and medicinal values of ascorbic acid.

  4. Enhancement of NMR and MRI in the presence of hyperpolarized noble gases

    DOEpatents

    Pines, Alexander; Budinger, Thomas; Navon, Gil; Song, Yi-Qiao; Appelt, Stephan; Bifone, Angelo; Taylor, Rebecca; Goodson, Boyd; Seydoux, Roberto; Room, Toomas; Pietrass, Tanja

    2004-11-16

    The present invention relates generally to nuclear magnetic resonance (NMR) techniques for both spectroscopy and imaging. More particularly, the present invention relates to methods in which hyperpolarized noble gases (e.g., Xe and He) are used to enhance and improve NMR and MRI. Additionally, the hyperpolarized gas solutions of the invention are useful both in vitro and in vivo to study the dynamics or structure of a system. When used with biological systems, either in vivo or in vitro, it is within the scope of the invention to target the hyperpolarized gas and deliver it to specific regions within the system.

  5. Complete biodegradable nature of calcium hydroxylapatite after injection for malar enhancement: an MRI study

    PubMed Central

    Pavicic, Tatjana

    2015-01-01

    Background Radiesse (Calcium hydroxylapatite [CaHA]) is a biocompatible, injectable gel for facial soft tissue augmentation. It is a completely biodegradable filler and this is well documented, but objective imaging methods to confirm this property are scarce. Methods We present a case report in which CaHA was injected into the midface of a 50-year-old woman for volume restoration and shaping of the cheek region. On the right side of the face, 1.6 mL CaHA was injected as several (5?7) small depots (0.1?0.2 mL) using a 28G 3/4 inch needle and the vertical supraperiosteal depot technique. On the contralateral side of the face, the subject received 1.6 mL CaHA over three entry points using a 27G 1 1/2 inch blunt cannula and the fanning technique. CaHA location and degradation were assessed using magnetic resonance imaging (MRI). Results CaHA appears as low-to-intermediate signal intensity on MRI images taken immediately after injection for malar enhancement with a symmetrical distribution. On MRI images taken 2.5 years after injection, no CaHA was visible but tissue volume remained increased, indicating a collagen-stimulating effect. The treatment was well tolerated. Conclusion In addition to producing long-lasting aesthetic and collagen-stimulating effects, MRI images confirm that CaHA is completely biodegradable with no product remaining 2.5 years after injection. PMID:25709485

  6. Quantitative effects of using compressed sensing in dynamic contrast enhanced MRI

    NASA Astrophysics Data System (ADS)

    Smith, David S.; Welch, E. Brian; Li, Xia; Arlinghaus, Lori R.; Loveless, Mary E.; Koyama, Tatsuki; Gore, John C.; Yankeelov, Thomas E.

    2011-08-01

    Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) involves the acquisition of images before, during and after the injection of a contrast agent. In order to perform quantitative modeling on the resulting signal intensity time course, data must be acquired rapidly, which compromises spatial resolution, signal to noise and/or field of view. One approach that may allow for gains in temporal or spatial resolution or signal to noise of an individual image is to use compressed sensing (CS) MRI. In this study, we demonstrate the accuracy of extracted pharmacokinetic parameters from DCE-MRI data obtained as part of pre-clinical and clinical studies in which fully sampled acquisitions have been retrospectively undersampled by factors of 2, 3 and 4 in Fourier space and then reconstructed with CS. The mean voxel-level concordance correlation coefficient for Ktrans (i.e. the volume transfer constant) obtained from the 2 accelerated and the fully sampled data is 0.92 and 0.90 for mouse and human data, respectively; for 3, the results are 0.79 and 0.79, respectively; for 4, the results are 0.64 and 0.70, respectively. The mean error in the tumor mean Ktrans for the mouse and human data at 2 acceleration is 1.8% and -4.2%, respectively; at 3, 3.6% and -10%, respectively; at 4, 7.8% and -12%, respectively. These results suggest that CS combined with appropriate reduced acquisitions may be an effective approach to improving image quality in DCE-MRI.

  7. Nanodelivery of MRI Contrast Agent Enhances Sensitivity of Detection of Lung Cancer Metastases

    PubMed Central

    Freedman, Matthew; Chang, Esther H.; Zhou, Qi; Pirollo, Kathleen F.

    2009-01-01

    Rationale and Objectives Early detection of lung cancer can be problematic. While current imaging methods can identify lung cancers, they are limited in the size of nodules detectable.. There is also lack of evidence that these methods can correctly classify nodules <7 mm as malignant since lung cancer can be mimicked in appearance by benign lesions that lower specificity. Therefore, there is a need for enhanced sensitivity/specificity of detection for small lung cancers. Materials and Methods We have developed a nanosized (~100nm) immunolipsome complex for delivery of molecular medicines to tumors. In this complex an anti-transferrin receptor single-chain antibody fragment (TfRscFv) decorates the surface of a cationic liposome encapsulating the payload. We have previously shown that this systemically administered complex (scL) selectively targets, and efficiently delivers its payload into, tumor cells. We have also encapsulated MRI contrast agent gadopentetate dimegulamine (gad-d) within this complex resulting in increased resolution and image intensity in a mouse model of primary cancer. Here we examine the ability of the scL-gad-d complex to increase the sensitivity of detection of lung metastases. Results These MRI studies show that the scL-gad-d nanocomplex is able to improve detection, and increase enhancement of, small lung cancers (400 microns and as small as 100 microns), when compared to that of uncomplexed gad-d. Conclusions Because of its tumor targeting specificity, deliver of an MRI contrast agent via this nanocomplex has potential for use as an agent that can identify small lung cancers, thus improving early detection and possibly increasing survival. PMID:19345904

  8. Imaging Modalities for Assessment of Treatment Response to Nonsurgical Hepatocellular Carcinoma Therapy: Contrast-Enhanced US, CT, and MRI

    PubMed Central

    Minami, Yasunori; Kudo, Masatoshi

    2015-01-01

    Tumor response and time to progression have been considered pivotal for surrogate assessment of treatment efficacy for patients with hepatocellular carcinoma (HCC). Recent advancements in imaging modalities such as contrast-enhanced ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) are playing an important role in assessing the therapeutic effects of HCC treatments. According to some HCC clinical guidelines, post-therapeutic evaluation of HCC patients is based exclusively on contrast-enhanced dynamic imaging criteria. The recommended techniques are contrast-enhanced CT or contrast-enhanced MRI. Contrast-enhanced US is employed more in the positive diagnosis of HCC than in post-therapeutic monitoring. Although contrast enhancement is an important finding on imaging, enhancement does not necessarily depict the same phenomenon across modalities. We need to become well acquainted with the characteristics of each modality, including not only contrast-enhanced CT and MRI but also contrast-enhanced US. Many nonsurgical treatment options are now available for unresectable HCC, and accurate assessment of tumor response is essential to achieve favorable outcomes. For the assessment of successful radiofrequency ablation (RFA), the achievement of a sufficient ablation margin as well the absence of tumor vascular enhancement is essential. To evaluate the response to transcatheter arterial chemoembolization (TACE), enhanced tumor shrinkage is relied on as a measure of antitumor activity. Here, we give an overview of the current status of imaging assessment of HCC response to nonsurgical treatments including RFA and TACE. PMID:26697413

  9. Sensitivity encoding as a means of enhancing the SNR efficiency in steady-state MRI.

    PubMed

    Weiger, Markus; Boesiger, Peter; Hilfiker, Paul R; Weishaupt, Dominik; Pruessmann, Klaas P

    2005-01-01

    Sensitivity encoding (SENSE) with a receiver coil array is typically used as a means of reducing the scan time in MRI. The speed benefit usually comes at some expense in terms of the signal-to-noise ratio (SNR) efficiency, which has been notorious as the main downside of SENSE and parallel MRI in general. In this work it is shown that in steady-state gradient-echo imaging the parallel approach may as well be used to increase the SNR efficiency. The basic idea is to balance reduced phase encoding by increasing the repetition time. In this fashion both the acquisition duty cycle and the steady-state magnetization can be enhanced, resulting in considerable net gains in SNR yield. It is argued that the reduction factor in parallel imaging is essentially an additional degree of freedom in optimizing the SNR. The optimal SENSE factor depends on scan, tissue, and hardware parameters, assuming values up to 3.0 and higher. The achievable SNR benefit also depends on the spoiling regime and is most pronounced for RF-spoiled techniques. The proposed mechanism is demonstrated by simulations and phantom experiments, as well as by contrast-enhanced angiography in vivo, achieving an approximate doubling of the SNR efficiency. PMID:15690517

  10. Clinical Performance of Contrast Enhanced Abdominal Pediatric MRI with Fast Combined Parallel Imaging Compressed Sensing Reconstruction

    PubMed Central

    Zhang, Tao; Chowdhury, Shilpy; Lustig, Michael; Barth, Richard A.; Alley, Marcus T.; Grafendorfer, Thomas; Calderon, Paul D.; Robb, Fraser J.L.; Pauly, John M.; Vasanawala, Shreyas S.

    2013-01-01

    Purpose To deploy clinically, a combined parallel imaging compressed sensing method with coil compression that achieves a rapid image reconstruction, and assess its clinical performance in contrast-enhanced abdominal pediatric MRI. Materials and Methods With IRB approval and informed patient consent/assent, 29 consecutive pediatric patients were recruited. Dynamic contrast-enhanced MRI was acquired on a 3T scanner using a dedicated 32-channel pediatric coil and a 3D SPGR sequence, with pseudo-random undersampling at a high acceleration (R=7.2). Undersampled data were reconstructed with three methods: a traditional parallel imaging method and a combined parallel imaging compressed sensing method with and without coil compression. The three sets of images were evaluated independently and blindly by two radiologists at one siting, for overall image quality and delineation of anatomical structures. Wilcoxon tests were performed to test the hypothesis that there was no significant difference in the evaluations, and inter-observer agreement was analyzed. Results Fast reconstruction with coil compression did not deteriorate image quality. The mean score of structural delineation of the fast reconstruction was 4.1 on a 5-point scale, significantly better (P<0.05) than traditional parallel imaging (mean score 3.1). Fair to substantial inter-observer agreement was reached in structural delineation assessment. Conclusion A fast combined parallel imaging compressed sensing method is feasible in a pediatric clinical setting. Preliminary results suggest it may improve structural delineation over parallel imaging. PMID:24127123

  11. Mn Enhancement and Respiratory Gating for In Utero MRI of the Embryonic Mouse Central Nervous System

    PubMed Central

    Deans, Abby E.; Wadghiri, Youssef Zaim; Berrios-Otero, Csar A.; Turnbull, Daniel H.

    2009-01-01

    The mouse is the preferred model organism for genetic studies of mammalian brain development. MRI has potential for in utero studies of mouse brain development, but has been limited previously by challenges of maximizing image resolution and contrast while minimizing artifacts due to physiological motion. Manganese (Mn)-enhanced MRI (MEMRI) studies have demonstrated central nervous system (CNS) contrast enhancement in mice from the earliest postnatal stages. The purpose of this study was to expand MEMRI to in utero studies of the embryonic CNS in combination with respiratory gating to decrease motion artifacts. We investigated MEMRI-facilitated CNS segmentation and three-dimensional (3D) analysis in wild-type mouse embryos from midgestation, and explored effects of Mn on embryonic survival and image contrast. Motivated by observations that MEMRI provided an effective method for visualization and volumetric analysis of embryonic CNS structures, especially in ventral regions, we used MEMRI to examine Nkx2.1 mutant mice that were previously reported to have ventral forebrain defects. Quantitative MEMRI analysis of Nkx2.1 knockout mice demonstrated volumetric changes in septum (SE) and basal ganglia (BG), as well as alterations in hypothalamic structures. This method may provide an effective means for in utero analysis of CNS phenotypes in a variety of mouse mutants. PMID:18506798

  12. Characterization of tumor vasculature in mouse brain by USPIO contrast-enhanced MRI.

    PubMed

    Gambarota, Giulio; Leenders, William

    2011-01-01

    Detailed characterization of the tumor vasculature provides a better understanding of the complex mechanisms associated with tumor development and is especially important to evaluate responses to current therapies which target the tumor vasculature. Magnetic resonance imaging (MRI) studies of tumors have been mostly performed using gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) contrast-enhanced imaging, which relies on Gd-DTPA leakage from hyperpermeable tumor vessels and subsequent accumulation in the tumor interstitium. In certain tumor types, especially diffuse glioma in the brain, incorporated tumor vessels are not necessarily leaky, complicating effective diagnosis via Gd-DTPA contrast-enhanced MRI. Another class of contrast agents, based on superparamagnetic ultrasmall iron oxide particles (USPIO), allows for non-invasive assessment of vascular volume within the tumor. Vascular volume can be obtained by calculating the change in water proton transverse relaxation rate (R (2) or R (2)) following USPIO administration. This allows for an objective comparison between vascular volumes of different tumors and also allows to perform longitudinal studies in order to assess, for example, treatment efficacy. Moreover, since the USPIO T (2) relaxivity is up to 20 times that of Gd-DTPA, USPIO provides a highly sensitive marker for alterations in vascular volume among tissues; this characteristic might be exploited for tumor detection. Thus, USPIO imaging may be a very attractive alternative to the most commonly used Gd-DTPA imaging and will at least have added value, especially for detection and delineation of diffuse infiltrative brain tumors. PMID:21874494

  13. Relationship between diffusion parameters derived from intravoxel incoherent motion MRI and perfusion measured by dynamic contrast-enhanced MRI of soft tissue tumors.

    PubMed

    Marzi, Simona; Stefanetti, Linda; Sperati, Francesca; Anelli, Vincenzo

    2016-01-01

    Our aim was to evaluate the link between diffusion parameters measured by intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) and the perfusion metrics obtained with dynamic contrast-enhanced (DCE) MRI in soft tissue tumors (STTs). Twenty-eight patients affected by histopathologically confirmed STT were included in a prospective study. All patients underwent both DCE MRI and IVIM DWI. The perfusion fraction f, diffusion coefficient D and perfusion-related diffusion coefficient D* were estimated using a bi-exponential function to fit the DWI data. DCE MRI was acquired with a temporal resolution of 3-5?s. Maps of the initial area under the gadolinium concentration curve (IAUGC), time to peak (TTP) and maximum slope of increase (MSI) were derived using commercial software. The relationships between the DCE MRI and IVIM DWI measurements were assessed by Spearman's test. To exclude false positive results under multiple testing, the false discovery rate (FDR) procedure was applied. The Mann-Whitney test was used to evaluate the differences between all variables in patients with non-myxoid and myxoid STT. No significant relationship was found between IVIM parameters and any DCE MRI parameters. Higher f and D*f values were found in non-myxoid tumors compared with myxoid tumors (p?=?0.004 and p?=?0.003, respectively). MSI was significantly higher in non-myxoid tumors than in myxoid tumors (p?=?0.029). From the visual assessments of single clinical cases, both f and D*f maps were in satisfactory agreement with DCE maps in the extreme cases of an avascular mass and a highly vascularized mass, whereas, for tumors with slight vascularity or with a highly heterogeneous perfusion pattern, this association was not straightforward. Although IVIM DWI was demonstrated to be feasible in STT, our data did not support evident relationships between perfusion-related IVIM parameters and perfusion measured by DCE MRI. Copyright 2015 John Wiley & Sons, Ltd. PMID:26602061

  14. The distribution of Mn2+ in rabbit eyes after topical administration for manganese-enhanced MRI

    PubMed Central

    Liang, Shenzhi; Liang, Miao; Zhu, Yu; Cheng, Jingliang; Yang, Zitao

    2015-01-01

    Purpose: To analyze the distribution of Mn2+ in rabbit eyes after topical administration of Mncl2 for manganese-enhanced MRI. Methods: Forty-eight Chinese white rabbits were divided into three groups. In group 1 (n = 4), the baseline concentration of Mn2+ in aqueous, vitreous and serum samples were analyzed. In group 2 and 3, the rabbits received one topical instillation (20 ?L) of Mncl2 (1 molL-1). In group 2 (n = 40), aqueous, vitreous and serum samples were collected and analyzed at predetermined time points (0.5, 1, 2, 4, 6, 12, 24, 48, 72 and 168 hours postdose). Assays were performed using inductively coupled plasma-mass spectrometer (ICP-MS). In group 3 (n = 4), after topical administration of Mncl2, dynamic manganese-enhanced MRI (MEMRI) was performed at predetermined time points. The signal-to-noise ratio (SNR) was calculated to evaluate the enhancements of eyes. Results: After topical administration, the maximum concentrations of Mn2+ in the aqueous and vitreous samples were 11.1641 0.7202 (2 hours) and 1.5622 0.1567 (12 hours). In group 3, the maximum enhancement of aqueous humor (SNR = 108.81 10.65) appeared at 2 hours postdose, whereas, no significant changes were detected in vitreous. Conclusion: Mn2+ could distribute into aqueous humor rapidly after topical administration of Mncl2, whereas, the concentration of Mn2+ in vitreous body fluctuated in a narrow range over the course. The uptake of Mn2+ in retina may involve several different pathways. PMID:25755783

  15. Interpretation and applicability of empirical tissue enhancement metrics in dynamic contrast-enhanced MRI based on a multiple pathway model

    NASA Astrophysics Data System (ADS)

    Koh, T. S.; Shi, W.; Thng, C. H.; Kwek, J. W.; Bisdas, S.; Khoo, J. B. K.

    2012-08-01

    Computer simulations based on a physiologically realistic tracer kinetic model with multiple pathways was used to provide insights on the applicability and interpretation of tissue enhancement metrics such as the maximum slope, peak enhancement and area under curve, commonly used in dynamic contrast-enhanced (DCE) MRI. Results show that physiological conditions of the tissue that could affect the accuracy of the maximal slope method include a high blood flow, increased variability of flow within the vasculature or a low vascular volume. Interestingly, changes in permeability and interstitial volume might not affect the accuracy of the maximal slope method. Time-to-peak and peak value of the tissue enhancement curve are not strictly properties of the tissue alone, and they cannot be linearly related to intrinsic tissue parameters such as blood flow, blood volume, capillary permeability, interstitial volume and mean transit time. Similar to the normalized initial area under tissue concentration curve, an alternative estimate of the total tracer distribution volume can be simply given by the ratio of tracer concentration in the tissue and artery sampled at the final DCE scan.

  16. The correlation of contrast-enhanced ultrasound and MRI perfusion quantitative analysis in rabbit VX2 liver cancer.

    PubMed

    Xiang, Zhiming; Liang, Qianwen; Liang, Changhong; Zhong, Guimian

    2014-12-01

    Our objective is to explore the value of liver cancer contrast-enhanced ultrasound (CEUS) and MRI perfusion quantitative analysis in liver cancer and the correlation between these two analysis methods. Rabbit VX2 liver cancer model was established in this study. CEUS was applied. Sono Vue was applied in rabbits by ear vein to dynamically observe and record the blood perfusion and changes in the process of VX2 liver cancer and surrounding tissue. MRI perfusion quantitative analysis was used to analyze the mean enhancement time and change law of maximal slope increasing, which were further compared with the pathological examination results. Quantitative indicators of liver cancer CEUS and MRI perfusion quantitative analysis were compared, and the correlation between them was analyzed by correlation analysis. Rabbit VX2 liver cancer model was successfully established. CEUS showed that time-intensity curve of rabbit VX2 liver cancer showed "fast in, fast out" model while MRI perfusion quantitative analysis showed that quantitative parameter MTE of tumor tissue increased and MSI decreased: the difference was statistically significant (P < 0.01). The diagnostic results of CEUS and MRI perfusion quantitative analysis were not significantly different (P > 0.05). However, the quantitative parameter of them were significantly positively correlated (P < 0.05). CEUS and MRI perfusion quantitative analysis can both dynamically monitor the liver cancer lesion and surrounding liver parenchyma, and the quantitative parameters of them are correlated. The combined application of both is of importance in early diagnosis of liver cancer. PMID:25123838

  17. Dynamic contrast-enhanced quantitative susceptibility mapping with ultrashort echo time MRI for evaluating renal function.

    PubMed

    Xie, Luke; Layton, Anita T; Wang, Nian; Larson, Peder E Z; Zhang, Jeff L; Lee, Vivian S; Liu, Chunlei; Johnson, G Allan

    2016-01-15

    Dynamic contrast-enhanced (DCE) MRI can provide key insight into renal function. DCE MRI is typically achieved through an injection of a gadolinium (Gd)-based contrast agent, which has desirable T1 quenching and tracer kinetics. However, significant T2* blooming effects and signal voids can arise when Gd becomes very concentrated, especially in the renal medulla and pelvis. One MRI sequence designed to alleviate T2* effects is the ultrashort echo time (UTE) sequence. In the present study, we observed T2* blooming in the inner medulla of the mouse kidney, despite using UTE at an echo time of 20 microseconds and a low dose of 0.03 mmol/kg Gd. We applied quantitative susceptibility mapping (QSM) and resolved the signal void into a positive susceptibility signal. The susceptibility values [in parts per million (ppm)] were converted into molar concentrations of Gd using a calibration curve. We determined the concentrating mechanism (referred to as the concentrating index) as a ratio of maximum Gd concentration in the inner medulla to the renal artery. The concentrating index was assessed longitudinally over a 17-wk course (3, 5, 7, 9, 13, 17 wk of age). We conclude that the UTE-based DCE method is limited in resolving extreme T2* content caused by the kidney's strong concentrating mechanism. QSM was able to resolve and confirm the source of the blooming effect to be the large positive susceptibility of concentrated Gd. UTE with QSM can complement traditional magnitude UTE and offer a powerful tool to study renal pathophysiology. PMID:26447222

  18. Layer-Specific Manganese-Enhanced MRI of the Retina in Light and Dark Adaptation

    PubMed Central

    De?La?Garza, Bryan H.; Li, Guang; Shih, Yen-Yu I.; Duong, Timothy Q.

    2012-01-01

    Purpose. To employ functional manganese-enhanced MRI (MEMRI) to image layer-specific changes in calcium-dependent activities in the rat retina during light versus dark adaptation. Methods. Functional MEMRI at 20 20 700 ?m was used to study light and dark adaptation in the same animals (N = 10) in which one eye was covered and the fellow eye was not. The activity encoding of the light and dark adaptation was achieved in awake conditions and imaged under anesthesia. T1-weighted MRI at 11.7 tesla (T) was performed using two identical radiofrequency transceiver coils to allow interleaved MRI acquisitions of the two eyes. An intravascular contrast agent was also used to verify layer assignments. Results. MEMRI detected contrasts among the inner retina, outer retina, and choroid. Independent confirmation of the vascular layers and boundaries between layers was documented with an intravascular contrast agent. The retinal layer thicknesses agreed with published data. The outer retina had lower MEMRI activity in light compared with dark adaption (P < 0.001), consistent with the increased metabolic demand associated with the dark current. The inner retina had higher MEMRI activity in light compared with dark adaption (P < 0.05). The choroid MEMRI activity was not statistically different between light and dark adaptation (P > 0.05). Conclusions. This study demonstrated a high-resolution MEMRI protocol to image functional activities among different layers of the retinas in awake animals during light and dark adaptation. This approach could have potential applications in animal models of retinal dysfunction. PMID:22669725

  19. Diffuse Infantile Hepatic Hemangioendothelioma With Early Central Enhancement in an Adult: A Case Report of CT and MRI Findings.

    PubMed

    Dong, Aisheng; Dong, Hui; Zuo, Changjing; He, Tianlin

    2015-12-01

    Infantile hepatic hemangioendothelioma (IHH) is the most common vascular tumor of the liver in infancy. Adult with IHH is extremely rare. We presented a diffuse IHH in an adult patient with computed tomography (CT) and magnetic resonance image (MRI) findings.A 39-year-old man was admitted to our hospital because of a 2-year history of abnormal liver function tests and a 7-day history of jaundice. Physical examination revealed enlarged liver. Unenhanced abdominal CT showed enlargement of the liver with diffuse hypodensity. Enhanced CT on the arterial phase revealed multiple centrally enhanced lesions diffusely involved the enlarged liver. The enhanced areas of the lesions became larger on the portal phase and all the lesions became homogeneous enhanced on the delayed phase. These lesions showed heterogeneously hyperintense on T2-weighted image, hypointense on T1-weighted image, and early centrally enhanced on dynamic gadolinium-enhanced MRI, with complete tumor enhancement after 180?s. The patient underwent orthotopic liver transplantation. IHH type 2 was confirmed by pathology. The patient died of tumor recurrence in the liver 4 months after transplantation.Unlike the previously described imaging appearances of IHH, this case showed diffuse nodules with early central enhancement on CT and MRI. Considering the importance of the ability to differentiate IHH from other hepatic tumors, radiologists should be aware of these imaging appearances to establish knowledge of the entire spectrum of IHH. PMID:26705232

  20. In vivo auditory brain mapping in mice with Mn-enhanced MRI

    PubMed Central

    Yu, Xin; Wadghiri, Youssef Zaim; Sanes, Dan H; Turnbull, Daniel H

    2007-01-01

    There are currently no noninvasive imaging methods available for auditory brain mapping in mice, despite the increasing use of genetically engineered mice to study auditory brain development and hearing loss. We developed a manganese-enhanced MRI (MEMRI) method to map regions of accumulated sound-evoked activity in awake, normally behaving mice. To demonstrate its utility for high-resolution (100-?m) brain mapping, we used MEMRI to show the tonotopic organization of the mouse inferior colliculus. To test its efficacy in an experimental setting, we acquired data from mice experiencing unilateral conductive hearing loss at different ages. Larger and persistent changes in auditory brainstem activity resulted when hearing loss occurred before the onset of hearing, showing that early hearing loss biases the response toward the functional ear. Thus, MEMRI provides a sensitive and effective method for mapping the mouse auditory brainstem and has great potential for a range of functional neuroimaging studies in normal and mutant mice. PMID:15924136

  1. Deconvolution of dynamic contrast-enhanced MRI data by linear inversion: choice of the regularization parameter.

    PubMed

    Sourbron, Steven; Luypaert, Rob; Van Schuerbeek, Peter; Dujardin, Martine; Stadnik, Tadeusz; Osteaux, Michel

    2004-07-01

    Truncated singular value decomposition (TSVD) is an effective method for the deconvolution of dynamic contrast-enhanced MRI. Two robust methods for the selection of the truncation threshold on a pixel-by-pixel basis--generalized cross validation (GCV) and the L-curve criterion (LCC)--were optimized and compared to paradigms in the literature. The methods lead to improvements in the estimate of the residue function and of its maximum and converge properly with SNR. The oscillations typically observed in the solution vanish entirely and perfusion is more accurately estimated at small mean transit times. This results in improved image contrast and increased sensitivity to perfusion abnormalities, at the cost of 1-2 min in calculation time and isolated instabilities in the image. It is argued that the latter problem may be resolved by optimization. Simulated results for GCV and LCC are equivalent in terms of performance, but GCV is faster. PMID:15236389

  2. Enhanced emotional reactivity after selective REM sleep deprivation in humans: an fMRI study

    PubMed Central

    Rosales-Lagarde, Alejandra; Armony, Jorge L.; del Ro-Portilla, Yolanda; Trejo-Martnez, David; Conde, Ruben; Corsi-Cabrera, Maria

    2012-01-01

    Converging evidence from animal and human studies suggest that rapid eye movement (REM) sleep modulates emotional processing. The aim of the present study was to explore the effects of selective REM sleep deprivation (REM-D) on emotional responses to threatening visual stimuli and their brain correlates using functional magnetic resonance imaging (fMRI). Twenty healthy subjects were randomly assigned to two groups: selective REM-D, by awakening them at each REM sleep onset, or non-rapid eye movement sleep interruptions (NREM-I) as control for potential non-specific effects of awakenings and lack of sleep. In a within-subject design, a visual emotional reactivity task was performed in the scanner before and 24 h after sleep manipulation. Behaviorally, emotional reactivity was enhanced relative to baseline (BL) in the REM deprived group only. In terms of fMRI signal, there was, as expected, an overall decrease in activity in the NREM-I group when subjects performed the task the second time, particularly in regions involved in emotional processing, such as occipital and temporal areas, as well as in the ventrolateral prefrontal cortex, involved in top-down emotion regulation. In contrast, activity in these areas remained the same level or even increased in the REM-D group, compared to their BL level. Taken together, these results suggest that lack of REM sleep in humans is associated with enhanced emotional reactivity, both at behavioral and neural levels, and thus highlight the specific role of REM sleep in regulating the neural substrates for emotional responsiveness. PMID:22719723

  3. Nanoparticle-Enhanced MRI to Evaluate Radiation Delivery to the Regional Lymphatics for Patients With Breast Cancer

    SciTech Connect

    MacDonald, Shannon M.; Harisinghani, Mukesh G.; Katkar, Amol; Napolitano, Brian; Wolfgang, John; Taghian, Alphonse G.

    2010-07-15

    Purpose: At present, radiation (RT) fields are based largely, and often solely, on bony anatomy. Recent efforts have been taken to better define lymphatic regions for RT planning. Lymphotrophic nanoparticle-enhanced MRI (LN-MRI) allows for accurate identification of malignant and benign lymph nodes. We sought to evaluate RT delivery to lymphatics for breast cancer using LN-MRI. Methods and Materials: Twenty-three patients with breast cancer underwent LN-MRI. MRIs were anatomically registered to a reference CT; benign and malignant lymph nodes were contoured. Standard RT fields were planned and dose calculated to prescribe 45-50 Gy. Lymphatic regions were contoured on CT. Coverage of LN-MRI lymph nodes by RT fields and contoured lymphatics were assessed. Results: Eighty-one percent of all lymph nodes defined by LN-MRI were covered by the 45-Gy isodose line; 82% of malignant and 79% of benign. The 50-Gy isodose line only encompassed 60% of LN-MRI defined lymph nodes-64% of malignant and 59% of benign. For nodal volumes contoured in the absence of a margin, 86% of actual lymph nodes were within contoured volumes. When a 5-mm expansion was added, 99% were included. Conclusions: LN-MRI is a useful tool to delineate the location of breast regional lymphatics. These results suggest less than desired coverage of lymph nodes using standard RT fields and that a margin may be advisable when defining nodal volumes by CT. The use of IMRT and RT in lieu of surgery makes accurate definition of the location of breast regional lymphatics of paramount importance.

  4. Gadolinium-enhanced MRI features of acute gouty arthritis on top of chronic gouty involvement in different joints.

    PubMed

    Emad, Yasser; Ragab, Yasser; El-Naggar, Ahmed; El-Shaarawy, Nashwa; Abd-Allah, Mayada A; Gamal, Rania M; Fathy, Ahmed; Hawass, Mona; Rasker, Johannes J

    2015-11-01

    The aims of the current study are to describe gadolinium-enhanced MRI features of an acute flare of established gouty arthritis in different joints and to examine a possible association between serum uric acid and MRI signs indicative of ongoing inflammation and/or structural joint damage as well as association with disease characteristics and laboratory findings. Twenty-seven male patients with established chronic gout agreed to participate, mean age 47.6 years, and mean disease duration in months 43.2 (31.8). For all patients, detailed demographic, disease characteristics, and laboratory findings were obtained and correlated with MRI findings. In 27 patients with established gout, a total of 50 MRI studies were performed of the following joints: feet joints (n?=?23), ankles (n?=?18), knees (n?=?5), and hand and wrist joints (n?=?4). MRI revealed capsular thickening in 19 patients, bone marrow edema (BME) in 15, soft tissue edema (STE) in 20, joint effusion in 21, bone erosions in 17, cartilaginous erosions in 4, and tenosynovitis in 9 cases. In 17 cases, tophaceous lesions were found. Post contrast MRI showed synovial thickening in seven cases. Positive correlations were observed between serum uric acid levels and the following MRI findings: capsular thickening (r?=?0.552, p?=?0.003), BME (r?=?0.668, p???0.0001), STE (r?=?0.559, p?=?0.002), and tenosynovitis (r?=?0.513, p?=?0.006). Using MRI in chronic gout, important features can be detected like BME, minute cartilaginous erosions, and hypertrophic synovial inflammation in post contrast MR images. Serum uric acid (SUA) was positively correlated with capsular thickening, BME, STE, and tenosynovitis. PMID:25681072

  5. Efficiency of Non-Contrast-Enhanced Liver Imaging Sequences Added to Initial Rectal MRI in Rectal Cancer Patients

    PubMed Central

    Kwon, Gene-hyuk; Kim, Kyung Ah; Hwang, Seong Su; Park, Soo Youn; Kim, Hyun A.; Choi, Sun Young; Kim, Ji Woong

    2015-01-01

    Purpose The purpose of this study was to estimate the value of addition of liver imaging to initial rectal magnetic resonance imaging (MRI) for detection of liver metastasis and evaluate imaging predictors of a high risk of liver metastasis on rectal MRI. Methods We enrolled 144 patients who from October 2010 to May 2013 underwent rectal MRI with T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) (b values = 50, 500, and 900 s/mm2) of the liver and abdominopelvic computed tomography (APCT) for the initial staging of rectal cancer. Two reviewers scored the possibility of liver metastasis on different sets of liver images (T2WI, DWI, and combined T2WI and DWI) and APCT and reached a conclusion by consensus for different analytic results. Imaging features from rectal MRI were also analyzed. The diagnostic performances of CT and an additional liver scan to detect liver metastasis were compared. Multivariate logistic regression to determine independent predictors of liver metastasis among rectal MRI features and tumor markers was performed. This retrospective study was approved by the Institutional Review Board, and the requirement for informed consent was waived. Results All sets of liver images were more effective than APCT for detecting liver metastasis, and DWI was the most effective. Perivascular stranding and anal sphincter invasion were statistically significant for liver metastasis (p = 0.0077 and p = 0.0471), while extramural vascular invasion based on MRI (mrEMVI) was marginally significant (p = 0.0534). Conclusion The addition of non-contrast-enhanced liver imaging, particularly DWI, to initial rectal MRI in rectal cancer patients could facilitate detection of liver metastasis without APCT. Perivascular stranding, anal sphincter invasion, and mrEMVI detected on rectal MRI were important imaging predictors of liver metastasis. PMID:26348217

  6. Enhancement and suppression in a lexical interference fMRI-paradigm

    PubMed Central

    Abel, Stefanie; Dressel, Katharina; Weiller, Cornelius; Huber, Walter

    2012-01-01

    Previous picture-word interference (PWI) fMRI-paradigms revealed ambiguous mechanisms underlying facilitation and inhibition in healthy subjects. Lexical distractors revealed increased (enhancement) or decreased (suppression) activation in language and monitoring/control areas. Performing a secondary examination and data analysis, we aimed to illuminate the relation between behavioral and neural interference effects comparing target-related distractors (REL) with unrelated distractors (UNREL). We hypothesized that interference involves both (A) suppression due to priming and (B) enhancement due to simultaneous distractor and target processing. Comparisons to UNREL should remain distractor unspecific even at a low threshold. (C) Distractor types with common characteristics should reveal overlapping brain areas. In a 3T MRI scanner, participants were asked to name pictures while auditory words were presented (stimulus onset asynchrony [SOA] = 200 msec). Associatively and phonologically related distractors speeded responses (facilitation), while categorically related distractors slowed them down (inhibition) compared to UNREL. As a result, (A) reduced brain activations indeed resembled previously reported patterns of neural priming. Each target-related distractor yielded suppressions at least in areas associated with vision and conflict/competition monitoring (anterior cingulate cortex [ACC]), revealing least priming for inhibitors. (B) Enhancements concerned language-related but distractor-unspecific regions. (C) Some wider brain regions were commonly suppressed for combinations of distractor types. Overlapping areas associated with conceptual priming were found for facilitatory distractors (inferior frontal gyri), and areas related to phonetic/articulatory processing (precentral gyri and left parietal operculum/insula) for distractors sharing feature overlap. Each distractor with semantic relatedness revealed nonoverlapping suppressions in lexical-phonological areas (superior temporal regions). To conclude, interference combines suppression of areas well known from neural priming and enhancement of language-related areas caused by dual activation from target and distractor. Differences between interference and priming need to be taken into account. The present interference paradigm has the potential to reveal the functioning of word-processing stages, cognitive control, and responsiveness to priming at the same time. PMID:22574280

  7. 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

    OBJECT 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. METHODS 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. RESULTS 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). CONCLUSIONS 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. PMID:26361281

  8. Quantitative activation-induced manganese-enhanced MRI reveals severity of Parkinsons disease in mice

    PubMed Central

    Kikuta, Satomi; Nakamura, Yukiyo; Yamamura, Yukio; Tamura, Atsushi; Homma, Noriyasu; Yanagawa, Yuchio; Tamura, Hajime; Kasahara, Jiro; Osanai, Makoto

    2015-01-01

    We demonstrate that activation-induced manganese-enhanced magnetic resonance imaging with quantitative determination of the longitudinal relaxation time (qAIM-MRI) reveals the severity of Parkinsons disease (PD) in mice. We first show that manganese ion-accumulation depends on neuronal activity. A highly active region was then observed by qAIM-MRI in the caudate-putamen in PD-model mice that was significantly correlated to the severity of PD, suggesting its involvement in the expression of PD symptoms. PMID:26255701

  9. Reproducibility of Dynamic Contrast-Enhanced MRI in Renal Cell Carcinoma

    PubMed Central

    Wang, Haiyi; Su, Zihua; Ye, Huiyi; Xu, Xiao; Sun, Zhipeng; Li, Lu; Duan, Feixue; Song, Yuanyuan; Lambrou, Tryphon; Ma, Lin

    2015-01-01

    Abstract The objective of this study was to investigate the intra- and interobserver as well as scanrescan reproducibility of quantitative parameters of renal cell carcinomas (RCCs) with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). A total of 21 patients with clear cell RCCs (17 men, 4 woman; age 3769 years, mean age 54.6 years, mean size, 5.0??2.2?cm) were prospectively recruited from September 2012 to November 2012. Patients underwent paired DCE-MRI studies on a 3.0 T MR system with an interval of 48 to 72 hours. The extended-Tofts model and population-based arterial input function were used to calculate kinetic parameters. Three observers defined the 2-dimensional whole-tumor region of interest at the slice with the maximum diameter of the RCC. Intraobserver and scanrescan differences were assessed using paired t tests, whereas interobserver differences using two-way analysis of variance. Intra- and interobserver reproducibility and scanrescan reproducibility were evaluated using within-subject coefficient of variation (wCoV) and intraclass correlation coefficient (ICC). There were no significant intra-, interobserver, or scanrescan differences in parameters (all P?>?0.05). All ICCs for intra- and interobserver agreements were >0.75 (P?30%). DCE-MRI demonstrated good intra- and interobserver reproducibility and moderate to good scanrescan performance in the assessment of RCC using Ktrans, Kep, and Ve as parameters under noncontinuous scanning mode. Vp showed poor reproducibility, and thus may not be suitable for this scanning protocol. PMID:26376399

  10. 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 LongEvans 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

  11. Whole-body kinetic image of a redox probe in mice using Overhauser-enhanced MRI.

    PubMed

    Kosem, Nuttavut; Naganuma, Tatsuya; Ichikawa, Kazuhiro; Phumala Morales, Noppawan; Yasukawa, Keiji; Hyodo, Fuminori; Yamada, Ken-Ichi; Utsumi, Hideo

    2012-07-15

    Overhauser-enhanced MRI (OMRI) enables visualization of free radicals in animals based on dynamic nuclear polarization. Real-time data of tissue redox status gathered from kinetic images of redox-sensitive nitroxyl radical probes using OMRI provided both anatomic and physiological information. Phantom experiments demonstrated the linear correlation between the enhancement factor and the concentration of a membrane-impermeable probe, carboxy-PROXYL (3-carboxy-2,2,5,5-tetramethyl- pyrrolidine-1-oxyl). Whole-body OMRI images illustrated the in vivo kinetics of carboxy-PROXYL for 25 min. Initial distribution was observed in lung, heart, liver, and kidney, but not brain, corresponding to its minimal lipophilicity. Based on these images (pixel size, 1.33 × 1.33 mm; slice thickness, 50mm), a time-concentration curve with low coefficient of variance (<0.21) was created to assess pharmacokinetic behaviors. A biexponential curve showed a distribution phase from 1 to 10 min and an elimination phase from 15 to 25 min. The α rate constant was greater than the β rate constant in ROIs, confirming that its pharmacokinetics obeyed a two-compartment model. As a noninvasive technique, combining OMRI imaging with redox probes to monitor tissue redox status may be useful in acquiring valuable information regarding organ function for preclinical and clinical studies of oxidative diseases. PMID:22579576

  12. Synergistic enhancement of MRI with Gd-DTPA and magnetization transfer.

    PubMed

    Tanttu, J I; Sepponen, R E; Lipton, M J; Kuusela, T

    1992-01-01

    Magnetization transfer (MT) between protons of macromolecules and protons of water molecules is a recently introduced mechanism for tissue contrast in MR imaging. The MT effect is strong in tissues where there is an efficient cross relaxation between macromolecular protons and water protons and where this interaction is the dominant source of relaxation. Paramagnetic ions shorten relaxation times and decrease the MT effect. These two facts led to the assumption that, in the case of contrast enhanced MRI, the combination of the T1-weighted imaging method and the MT technique may yield increased contrast, compared with standard methods. The synergistic effect is demonstrated in this work with studies of egg white samples and by imaging three patients with different brain pathologies. The lesion-to-white matter contrasts, with standard T1-weighted sequences with and without the MT effect, were compared before and after the introduction of Gd-DTPA. In each case the synergistic effect of T1 weighting and MT improved the contrast enhancement provided with Gd-diethylenetriamine pentaacetic acid. PMID:1729300

  13. Parametric mapping of the hepatic perfusion index with gadolinium-enhanced volumetric MRI.

    PubMed

    White, M J; O'Gorman, R L; Charles-Edwards, E M; Kane, P A; Karani, J B; Leach, M O; Totman, J J

    2007-02-01

    The purpose of this study was to adapt the hepatic perfusion index (HPI) methodology previously developed for MRI to derive 3D parametric maps of HPI, and to investigate apparent differences in HPI maps between a group of colorectal cancer patients and controls. To achieve this, a new and simpler approach to HPI calculation which does not require measurements from the aorta or portal vein is introduced, and assessed with large liver regions of interest (ROIs) in patients and controls. Several example HPI maps showing localized variation are then presented. The subject group consisted of 12 patients with known colorectal metastases, and 13 control subjects referred for routine contrast-enhanced spine imaging with no history of neoplastic disease. HPI was evaluated from serial T1 volume acquisitions acquired over the course of a Gd-DTPA bolus injection. Regions of abnormal perfusion were visible on the HPI maps derived for the patient group, manifested as areas of locally increased HPI extending around the visible margins of known metastases evident on the conventional contrast-enhanced images. This method for MR voxel-based parametric mapping of HPI has the potential to demonstrate regional variations in perfusion at the segmental and subsegmental level. PMID:16854961

  14. Dynamic Contrast-Enhanced MRI Kinetics of Invasive Breast Cancer: A Potential Prognostic Marker for Radiation Therapy

    SciTech Connect

    Loiselle, Christopher R.; Eby, Peter R.; DeMartini, Wendy B.; Peacock, Sue M.S.; Bittner, Nathan; Lehman, Constance D.; Kim, Janice N.

    2010-04-15

    Purpose: Our goal was to determine the correlations between dynamic contrast-enhanced MRI (DCE-MRI) kinetics of breast cancers and axillary nodal status (ANS) which may have prognostic value in designing radiation therapy recommendations. Methods and Materials: A retrospective review identified 167 consecutive patients treated with external beam radiotherapy for invasive breast cancer from Jan 1, 2006 to Nov 1, 2007. Patients with DCE-MRI kinetic data from our institution who underwent axillary surgical staging prior to chemotherapy were included. ANS was assessed as positive or negative by pathology record review. For each primary cancer, maximum tumor diameter and kinetic values for initial peak enhancement (PE), percent initial rapid enhancement (RE), and percent delayed washout enhancement (WE) were measured with a computer-aided evaluation program. Univariate, multivariate, and receiver operating characteristic curve analyses were performed according to the ANS. Results: Forty-six patients met study criteria, with 32 (70%) node-negative and 14 (30%) node-positive patients. Median PE was significantly greater in node-positive patients (209%) than in node-negative patients (138%, p = 0.0027). Similarly, median RE was significantly greater in node-positive patients (57%) than in node-negative patients (27%, p = 0.0436). WE was not different between groups (p = 0.9524). Median maximum tumor diameter was greater in node-positive patients (26 mm) than in node-negative patients (15 mm, p = 0.015). Multivariate analysis showed that only PE trended toward significance (p = 0.18). Conclusions: DCE-MRI kinetics of primary breast cancers correlate with ANS. Multivariate analysis demonstrates the correlation is not due simply to underlying lesion size. If validated prospectively, DCE-MRI kinetics may aid as a tool in selecting patients or designing fields for radiation therapy.

  15. Myelin mapping in the central nervous system of living mice using contrast-enhanced magnetization transfer MRI.

    PubMed

    Watanabe, Takashi; Frahm, Jens; Michaelis, Thomas

    2012-11-01

    This work compares magnetization transfer (MT) MRI of living mice with contrast-enhanced MT MRI using intraventricular administration of gadopentetate dimeglumine (Gd-DTPA), systemic administration of MnCl2, and both. In MT MRI at 9.4 T, the contrast-to-noise ratio (CNR) between white matter (WM) and gray matter (GM) increased by 85% after Gd-DTPA injection into the lateral ventricle. When applied in conjunction with manganese-enhanced MT MRI (117 ?m isotropic resolution, 6 min measuring time), Gd-DTPA boosted the CNR increase from +56% to +117%. Additional T1 measurements at 2.35 T revealed that intraventricular Gd-DTPA shortens the T1 of GM much more than that of WM, which corresponds to estimated extracellular spaces of 26% in GM and only 15% in WM. These results explain the additional MT contrast enhancement by Gd-DTPA and demonstrate that the T1 shortening by intracellular Mn2+ is well complemented by extracellular Gd-DTPA. The data suggest a high myelin and low water content to hinder access of hydrophilic paramagnetic agents, so that the resulting differential accumulation effectively reduces the MT saturation in water-rich tissues and thereby facilitates the mapping of myelin-rich tissues. Finally, a 156% CNR increase between GM and WM for contrast-enhanced MT MRI at 9.4T using both Gd-DTPA and manganese allowed for 60?m isotropic resolution (102 min measuring time), which delineated myelinated fibers and layers even within GM areas such as the thalamus and cerebellar cortex. Improved MT contrasts were also seen in the cervical spinal cord. PMID:22796983

  16. Practical Dynamic Contrast Enhanced MRI in Small Animal Models of Cancer: Data Acquisition, Data Analysis, and Interpretation

    PubMed Central

    Barnes, Stephanie L.; Whisenant, Jennifer G.; Loveless, Mary E.; Yankeelov, Thomas E.

    2012-01-01

    Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) consists of the continuous acquisition of images before, during, and after the injection of a contrast agent. DCE-MRI allows for noninvasive evaluation of tumor parameters related to vascular perfusion and permeability and tissue volume fractions, and is frequently employed in both preclinical and clinical investigations. However, the experimental and analytical subtleties of the technique are not frequently discussed in the literature, nor are its relationships to other commonly used quantitative imaging techniques. This review aims to provide practical information on the development, implementation, and validation of a DCE-MRI study in the context of a preclinical study (though we do frequently refer to clinical studies that are related to these topics). PMID:23105959

  17. Corticospinal Tract Tracing in the Marmoset with a Clinical Whole-Body 3T Scanner Using Manganese-Enhanced MRI

    PubMed Central

    Plas, Benjamin; Bolan, Faye; Boulanouar, Kader; Renaud, Luc; Darmana, Robert; Vaysse, Laurence; Vieu, Christophe; Loubinoux, Isabelle

    2015-01-01

    Manganese-enhanced MRI (MEMRI) has been described as a powerful tool to depict the architecture of neuronal circuits. In this study we investigated the potential use of in vivo MRI detection of manganese for tracing neuronal projections from the primary motor cortex (M1) in healthy marmosets (Callithrix Jacchus). We determined the optimal dose of manganese chloride (MnCl2) among 800, 400, 40 and 8nmol that led to manganese-induced hyperintensity furthest from the injection site, as specific to the corticospinal tract as possible, and that would not induce motor deficit. A commonly available 3T human clinical MRI scanner and human knee coil were used to follow hyperintensity in the corticospinal tract 24h after injection. A statistical parametric map of seven marmosets injected with the chosen dose, 8 nmol, showed the corticospinal tract and M1 connectivity with the basal ganglia, substantia nigra and thalamus. Safety was determined for the lowest dose that did not induce dexterity and grip strength deficit, and no behavioral effects could be seen in marmosets who received multiple injections of manganese one month apart. In conclusion, our study shows for the first time in marmosets, a reliable and reproducible way to perform longitudinal ME-MRI experiments to observe the integrity of the marmoset corticospinal tract on a clinical 3T MRI scanner. PMID:26398500

  18. In vivo detection of developing vessel occlusion in photothrombotic ischemic brain lesions in the rat by iron particle enhanced MRI.

    PubMed

    Kleinschnitz, Christoph; Schtz, Ansgar; Nlte, Ingo; Horn, Tanja; Frank, Marco; Solymosi, Laszlo; Stoll, Guido; Bendszus, Martin

    2005-11-01

    The aim of our study was to visualize developing vessel occlusion in focal cerebral ischemia in vivo. Cortical photothrombosis (PT) was induced in rats, which in addition received superparamagnetic iron oxide (SPIO) particles intravenously. When SPIO particles were applied simultaneously during illumination of the brain for induction of PT, animals showed a markedly hypointense cortical lesion on T2-weighted (T2-w) magnetic-resonance images (MRI). At 3 h after PT, this hypointense area was surrounded by a small hyperintense rim. At 48 h after PT the hyperintense rim had further extended, whereas the hypointense lesion core did not change in size or signal. On histological sections areas of signal loss on T2-w MRI corresponded to local accumulation of iron particles, which were trapped within vessel thrombi. When SPIO particles were applied at 2 h after PT, the lesion appeared hyperintense on T2-w MRI, but was surrounded by a small hypointense rim indicating ongoing vessel occlusion at its outer margins. In contrast, delayed SPIO application at 24 h after completion of PT produced a merely hyperintense cortical lesion on T2-w MRI. Correspondingly, no iron deposits were seen on tissue sections. In conclusion, early SPIO-enhanced MRI provides a reliable in vivo tool to delineate areas of developing vessel occlusion in experimental cerebral ischemia and identifies vessel thrombosis as one mechanism of secondary infarct growth in the PT paradigm. This new imaging technique may aid to evaluate antithrombotic treatment strategies in the future. PMID:15917747

  19. Magic Angle–Enhanced MRI of Fibrous Microstructures in Sclera and Cornea With and Without Intraocular Pressure Loading

    PubMed Central

    Ho, Leon C.; Sigal, Ian A.; Jan, Ning-Jiun; Squires, Alexander; Tse, Zion; Wu, Ed X.; Kim, Seong-Gi; Schuman, Joel S.; Chan, Kevin C.

    2014-01-01

    Purpose. The structure and biomechanics of the sclera and cornea are central to several eye diseases such as glaucoma and myopia. However, their roles remain unclear, partly because of limited noninvasive techniques to assess their fibrous microstructures globally, longitudinally, and quantitatively. We hypothesized that magic angle–enhanced magnetic resonance imaging (MRI) can reveal the structural details of the corneoscleral shell and their changes upon intraocular pressure (IOP) elevation. Methods. Seven ovine eyes were extracted and fixed at IOP = 50 mm Hg to mimic ocular hypertension, and another 11 eyes were unpressurized. The sclera and cornea were scanned at different angular orientations relative to the main magnetic field inside a 9.4-Tesla MRI scanner. Relative MRI signal intensities and intrinsic transverse relaxation times (T2 and T2*) were determined to quantify the magic angle effect on the corneoscleral shells. Three loaded and eight unloaded tendon samples were scanned as controls. Results. At magic angle, high-resolution MRI revealed distinct scleral and corneal lamellar fibers, and light/dark bands indicative of collagen fiber crimps in the sclera and tendon. Magic angle enhancement effect was the strongest in tendon and the least strong in cornea. Loaded sclera, cornea, and tendon possessed significantly higher T2 and T2* than unloaded tissues at magic angle. Conclusions. Magic angle–enhanced MRI can detect ocular fibrous microstructures without contrast agents or coatings and can reveal their MR tissue property changes with IOP loading. This technique may open up new avenues for assessment of the biomechanical and biochemical properties of ocular tissues in aging and in diseases involving the corneoscleral shell. PMID:25103267

  20. Three-dimensional dynamic contrast-enhanced MRI for the accurate, extensive quantification of microvascular permeability in atherosclerotic plaques.

    PubMed

    Calcagno, Claudia; Lobatto, Mark E; Dyvorne, Hadrien; Robson, Philip M; Millon, Antoine; Senders, Max L; Lairez, Olivier; Ramachandran, Sarayu; Coolen, Bram F; Black, Alexandra; Mulder, Willem J M; Fayad, Zahi A

    2015-10-01

    Atherosclerotic plaques that cause stroke and myocardial infarction are characterized by increased microvascular permeability and inflammation. Dynamic contrast-enhanced MRI (DCE-MRI) has been proposed as a method to quantify vessel wall microvascular permeability in?vivo. Until now, most DCE-MRI studies of atherosclerosis have been limited to two-dimensional (2D) multi-slice imaging. Although providing the high spatial resolution required to image the arterial vessel wall, these approaches do not allow the quantification of plaque permeability with extensive anatomical coverage, an essential feature when imaging heterogeneous diseases, such as atherosclerosis. To our knowledge, we present the first systematic evaluation of three-dimensional (3D), high-resolution, DCE-MRI for the extensive quantification of plaque permeability along an entire vascular bed, with validation in atherosclerotic rabbits. We compare two acquisitions: 3D turbo field echo (TFE) with motion-sensitized-driven equilibrium (MSDE) preparation and 3D turbo spin echo (TSE). We find 3D TFE DCE-MRI to be superior to 3D TSE DCE-MRI in terms of temporal stability metrics. Both sequences show good intra- and inter-observer reliability, and significant correlation with ex?vivo permeability measurements by Evans Blue near-infrared fluorescence (NIRF). In addition, we explore the feasibility of using compressed sensing to accelerate 3D DCE-MRI of atherosclerosis, to improve its temporal resolution and therefore the accuracy of permeability quantification. Using retrospective under-sampling and reconstructions, we show that compressed sensing alone may allow the acceleration of 3D DCE-MRI by up to four-fold. We anticipate that the development of high-spatial-resolution 3D DCE-MRI with prospective compressed sensing acceleration may allow for the more accurate and extensive quantification of atherosclerotic plaque permeability along an entire vascular bed. We foresee that this approach may allow for the comprehensive and accurate evaluation of plaque permeability in patients, and may be a useful tool to assess the therapeutic response to approved and novel drugs for cardiovascular disease. PMID:26332103

  1. Enhanced cardio vascular image analysis by combined representation of results from dynamic MRI and anatomic CTA

    NASA Astrophysics Data System (ADS)

    Kuehnel, C.; Hennemuth, A.; Oeltze, S.; Boskamp, T.; Peitgen, H.-O.

    2008-03-01

    The diagnosis support in the field of coronary artery disease (CAD) is very complex due to the numerous symptoms and performed studies leading to the final diagnosis. CTA and MRI are on their way to replace invasive catheter angiography. Thus, there is a need for sophisticated software tools that present the different analysis results, and correlate the anatomical and dynamic image information. We introduce a new software assistant for the combined result visualization of CTA and MR images, in which a dedicated concept for the structured presentation of original data, segmentation results, and individual findings is realized. Therefore, we define a comprehensive class hierarchy and assign suitable interaction functions. User guidance is coupled as closely as possible with available data, supporting a straightforward workflow design. The analysis results are extracted from two previously developed software assistants, providing coronary artery analysis and measurements, function analysis as well as late enhancement data investigation. As an extension we introduce a finding concept directly relating suspicious positions to the underlying data. An affine registration of CT and MR data in combination with the AHA 17-segment model enables the coupling of local findings to positions in all data sets. Furthermore, sophisticated visualization in 2D and 3D and interactive bull's eye plots facilitate a correlation of coronary stenoses and physiology. The software has been evaluated on 20 patient data sets.

  2. Modified Wideband Three-Dimensional Late Gadolinium Enhancement MRI for Patients with Implantable Cardiac Devices

    PubMed Central

    Rashid, Shams; Rapacchi, Stanislas; Shivkumar, Kalyanam; Plotnik, Adam; Finn, J. Paul; Hu, Peng

    2015-01-01

    Purpose To study the effects of cardiac devices on three-dimensional (3D) late gadolinium enhancement (LGE) MRI and to develop a 3D LGE protocol for implantable cardioverter defibrillator (ICD) patients with reduced image artifacts. Theory and Methods The 3D LGE sequence was modified by implementing a wideband inversion pulse, which reduces hyperintensity artifacts, and by increasing bandwidth of the excitation pulse. The modified wideband 3D LGE sequence was tested in phantoms and evaluated in six volunteers and five patients with ICDs. Results Phantom and in vivo studies results demonstrated extended signal void and ripple artifacts in 3D LGE that were associated with ICDs. The reason for these artifacts was slab profile distortion and the subsequent aliasing in the slice-encoding direction. The modified wideband 3D LGE provided significantly reduced ripple artifacts than 3D LGE with wideband inversion only. Comparison of 3D and 2D LGE images demonstrated improved spatial resolution of the heart using 3D LGE. Conclusion Increased bandwidth of the inversion and excitation pulses can significantly reduce image artifacts associated with ICDs. Our modified wideband 3D LGE protocol can be readily used for imaging patients with ICDs given appropriate safety guidelines are followed. PMID:25772155

  3. DCEMRI.jl: a fast, validated, open source toolkit for dynamic contrast enhanced MRI analysis

    PubMed Central

    Li, Xia; Arlinghaus, Lori R.; Yankeelov, Thomas E.; Welch, E. Brian

    2015-01-01

    We present a fast, validated, open-source toolkit for processing dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) data. We validate it against the Quantitative Imaging Biomarkers Alliance (QIBA) Standard and Extended Tofts-Kety phantoms and find near perfect recovery in the absence of noise, with an estimated 1020 speedup in run time compared to existing tools. To explain the observed trends in the fitting errors, we present an argument about the conditioning of the Jacobian in the limit of small and large parameter values. We also demonstrate its use on an in vivo data set to measure performance on a realistic application. For a 192 192 breast image, we achieved run times of <1 s. Finally, we analyze run times scaling with problem size and find that the run time per voxel scales as O(N1.9), where N is the number of time points in the tissue concentration curve. DCEMRI.jl was much faster than any other analysis package tested and produced comparable accuracy, even in the presence of noise. PMID:25922795

  4. Manganese-impregnated mesoporous silica nanoparticles for signal enhancement in MRI cell labelling studies.

    PubMed

    Guillet-Nicolas, Rmy; Laprise-Pelletier, Myriam; Nair, Mahesh M; Chevallier, Pascale; Lagueux, Jean; Gossuin, Yves; Laurent, Sophie; Kleitz, Freddy; Fortin, Marc-Andr

    2013-12-01

    Mesoporous silica nanoparticles (MSNs) are used in drug delivery and cell tracking applications. As Mn(2+) is already implemented as a "positive" cell contrast agent in preclinical imaging procedures (in the form of MnCl2 for neurological studies), the introduction of Mn in the porous network of MSNs would allow labelling cells and tracking them using MRI. These particles are in general internalized in endosomes, an acidic environment with high saline concentration. In addition, the available MSN porosity could also serve as a carrier to deliver medical/therapeutic substances through the labelled cells. In the present study, manganese oxide was introduced in the porous network of MCM-48 silica nanoparticles (Mn-M48SNs). The particles exhibit a narrow size distribution (~140 nm diam.) and high porosity (~60% vol.), which was validated after insertion of Mn. The resulting Mn-M48SNs were characterized by TEM, N2 physisorption, and XRD. Evidence was found with H2-TPR, and XPS characterization, that Mn(II) is the main oxidation state of the paramagnetic species after suspension in water, most probably in the form of Mn-OOH. The colloidal stability as a function of time was confirmed by DLS in water, acetate buffer and cell culture medium. In NMR data, no significant evidence of Mn(2+) leaching was found in Mn-M48SNs in acidic water (pH 6), up to 96 hours after suspension. High longitudinal relaxivity values of r1 = 8.4 mM(-1) s(-1) were measured at 60 MHz and 37 C, with the lowest relaxometric ratios (r2/r1 = 2) reported to date for a Mn-MSN system. Leukaemia cells (P388) were labelled with Mn-M48SNs and nanoparticle cell internalization was confirmed by TEM. Finally, MRI contrast enhancement provided by cell labelling with escalated incubation concentrations of Mn-M48SNs was quantified at 1 T. This study confirmed the possibility of efficiently confining Mn into M48SNs using incipient wetness, while maintaining an open porosity and relatively high pore volume. Because these Mn-labelled M48SNs express strong "positive" contrast media properties at low concentrations, they are potentially applicable for cell tracking and drug delivery methodologies. PMID:24178890

  5. Does the Gadoxetic Acid-Enhanced Liver MRI Impact on the Treatment of Patients with Colorectal Cancer? Comparison Study with 18F-FDG PET/CT

    PubMed Central

    Oh, Ji-Won; Oh, Soon Nam; Choi, Joon Il; Choi, Moon Hyung; Yoo, Ie Ryung; Lee, Myung Ah; Yoo, Young-Kyung; Oh, Seong Taek

    2016-01-01

    Objectives. We evaluated the value of Gadoxetic acid-enhanced liver MRI in the preoperative staging of colorectal cancer and estimated the clinical impact of liver MRI in the management plan of liver metastasis. Methods. We identified 108 patients who underwent PET/CT and liver MRI as preoperative evaluation of colorectal cancer, between January 2011 and December 2013. We evaluated the per nodule sensitivity of PET/CT and liver MRI for liver metastasis. Management plan changes were estimated for patients with metastatic nodules newly detected on liver MRI, to assess the clinical impact. Results. We enrolled 131 metastatic nodules (mean size 1.6 cm) in 41 patients (mean age 65 years). The per nodule sensitivities of PET/CT and liver MRI were both 100% for nodules measuring 2 cm or larger but were significantly different for nodules measuring less than 2 cm (59.8% and 95.1%, resp., P = 0.0001). At least one more metastatic nodule was detected on MRI in 16 patients. Among these, 7 patients indicated changes of management plan after performing MRI. Conclusions. Gadoxetic acid-enhanced liver MRI detected more metastatic nodules compared with PET/CT, especially for small (<2 cm) nodules. The newly detected nodules induced management plan change in 43.8% (7/16) of patients.

  6. 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 ?L 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 ?L dose, 1.339 (0.013 SE) at the 150 ?L dose, and 1.287 (0.014 SE) at the 200 ?L dose. DCE-MRI peak tumor enhancement at the 150 ?L dose was significantly greater than both the 100 ?L dose (p < 3.323E-08) and 200 ?L dose (p < 0.0007396). Discussion: In this preliminary study, the 150 ?L 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.

  7. Non-invasive visualization of in vivo drug delivery of poly(L-glutamic acid) using contrast enhanced MRI

    PubMed Central

    Ye, Furong; Ke, Tianyi; Jeong, Eun-Kee; Wang, Xuli; Sun, Yongen; Johnson, Melody; Lu, Zheng-Rong

    2008-01-01

    Biomedical imaging is valuable for non-invasive investigation of in vivo drug delivery with polymer conjugates. It can provide real-time information on pharmacokinetics, biodistribution and drug delivery efficiency of the conjugates. Non-invasive visualization of in vivo drug delivery of polymer conjugates with contrast enhanced magnetic resonance imaging (MRI) was studied with paramagnetically labeled poly(L-glutamic acid) in an animal tumor model. Poly(L-glutamic acid) is a biocompatible and biodegradable drug carrier for diagnostics and therapeutics. Poly(L-glutamic acid)-1,6-hexanediamine-(Gd-DO3A) conjugates with molecular weights of 87, 50 and 28 KDa and narrow molecular weight distributions were prepared and studied in mice bearing MDA-MB-231 human breast cancer xenografts. Contrast enhanced MRI resulted in real-time and three-dimensional visualization of blood circulation, pharmacokinetics, biodistribution and tumor accumulation of the conjugates, and the size effect on these pharmaceutics properties. The conjugate of 28 KDa rapidly cleared from the circulation and had a relatively lower tumor accumulation. The conjugates with higher molecular weights exhibited a more prolonged blood circulation and higher tumor accumulation. The difference between the conjugates of 87 and 50 KDa was not significant. Contrast enhanced MRI is effective for non-invasive real-time visualization of in vivo drug delivery of paramagnetically labeled polymer conjugates. PMID:17009849

  8. Differentiation of Malignant and Benign Breast Lesions Using Magnetization Transfer Imaging and Dynamic Contrast-enhanced MRI

    PubMed Central

    Heller, Samantha L.; Moy, Linda; Lavianlivi, Sherlin; Moccaldi, Melanie; Kim, Sungheon

    2013-01-01

    Purpose To evaluate feasibility of using magnetization transfer ratio (MTR) in conjunction with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for differentiation of benign and malignant breast lesions at 3 Tesla. Materials and Methods This prospective study was IRB and HIPAA compliant. DCE-MRI scans followed by MT imaging were performed on 41 patients. Region of interests (ROI’s) were drawn on co-registered MTR and DCE post-contrast images for breast structures, including benign lesions (BL) and malignant lesions (ML). Initial enhancement ratio (IER) and delayed enhancement ratio (DER) were calculated, as were normalized MTR, DER and IER (NMTR, NDER, NIER) values. Diagnostic accuracy analysis was performed. Results Mean MTR in ML was lower than in BL (p <0.05); mean DER and mean IER in ML were significantly higher than in BL (p<0.01, p<0.001). NMTR, NDER, and NIER were significantly lower in ML versus BL (p<0.007, p<0.001, p<0.001). IER had highest diagnostic accuracy (77.6%), sensitivity (86.2%), and area under the ROC curve (.879). MTR specificity was 100%. Logistic regression modeling with NMTR and NIER yielded best results for BL versus ML (sensitivity 93.1%, specificity 80%, AUC 0.884, accuracy 83.7%). Conclusion Isolated quantitative DCE analysis may increase specificity of breast MR for differentiating BL and ML. DCE-MRI with NMTR may produce a robust means of evaluating breast lesions. PMID:23097239

  9. Development and characterization of a dynamic lesion phantom for the quantitative evaluation of dynamic contrast-enhanced MRI

    PubMed Central

    Freed, Melanie; de Zwart, Jacco A.; Hariharan, Prasanna; R. Myers, Matthew; Badano, Aldo

    2011-01-01

    Purpose: To develop a dynamic lesion phantom that is capable of producing physiological kinetic curves representative of those seen in human dynamic contrast-enhanced MRI (DCE-MRI) data. The objective of this phantom is to provide a platform for the quantitative comparison of DCE-MRI protocols to aid in the standardization and optimization of breast DCE-MRI. Methods: The dynamic lesion consists of a hollow, plastic mold with inlet and outlet tubes to allow flow of a contrast agent solution through the lesion over time. Border shape of the lesion can be controlled using the lesion mold production method. The configuration of the inlet and outlet tubes was determined using fluid transfer simulations. The total fluid flow rate was determined using x-ray images of the lesion for four different flow rates (0.25, 0.5, 1.0, and 1.5 ml?s) to evaluate the resultant kinetic curve shape and homogeneity of the contrast agent distribution in the dynamic lesion. High spatial and temporal resolution x-ray measurements were used to estimate the true kinetic curve behavior in the dynamic lesion for benign and malignant example curves. DCE-MRI example data were acquired of the dynamic phantom using a clinical protocol. Results: The optimal inlet and outlet tube configuration for the lesion molds was two inlet molds separated by 30 and a single outlet tube directly between the two inlet tubes. X-ray measurements indicated that 1.0 ml?s was an appropriate total fluid flow rate and provided truth for comparison with MRI data of kinetic curves representative of benign and malignant lesions. DCE-MRI data demonstrated the ability of the phantom to produce realistic kinetic curves. Conclusions: The authors have constructed a dynamic lesion phantom, demonstrated its ability to produce physiological kinetic curves, and provided estimations of its true kinetic curve behavior. This lesion phantom provides a tool for the quantitative evaluation of DCE-MRI protocols, which may lead to improved discrimination of breast cancer lesions. PMID:21992378

  10. Automated segmentation of reference tissue for prostate cancer localization in dynamic contrast enhanced MRI

    NASA Astrophysics Data System (ADS)

    Vos, Pieter C.; Hambrock, Thomas; Barentsz, Jelle O.; Huisman, Henkjan J.

    2010-03-01

    For pharmacokinetic (PK) analysis of Dynamic Contrast Enhanced (DCE) MRI the arterial input function needs to be estimated. Previously, we demonstrated that PK parameters have a significant better discriminative performance when per patient reference tissue was used, but required manual annotation of reference tissue. In this study we propose a fully automated reference tissue segmentation method that tackles this limitation. The method was tested with our Computer Aided Diagnosis (CADx) system to study the effect on the discriminating performance for differentiating prostate cancer from benign areas in the peripheral zone (PZ). The proposed method automatically segments normal PZ tissue from DCE derived data. First, the bladder is segmented in the start-to-enhance map using the Otsu histogram threshold selection method. Second, the prostate is detected by applying a multi-scale Hessian filter to the relative enhancement map. Third, normal PZ tissue was segmented by threshold and morphological operators. The resulting segmentation was used as reference tissue to estimate the PK parameters. In 39 consecutive patients carcinoma, benign and normal tissue were annotated on MR images by a radiologist and a researcher using whole mount step-section histopathology as reference. PK parameters were computed for each ROI. Features were extracted from the set of ROIs using percentiles to train a support vector machine that was used as classifier. Prospective performance was estimated by means of leave-one-patient-out cross validation. A bootstrap resampling approach with 10,000 iterations was used for estimating the bootstrap mean AUCs and 95% confidence intervals. In total 42 malignant, 29 benign and 37 normal regions were annotated. For all patients, normal PZ was successfully segmented. The diagnostic accuracy obtained for differentiating malignant from benign lesions using a conventional general patient plasma profile showed an accuracy of 0.64 (0.53-0.74). Using the automated per-patient calibration method the diagnostic performance improved significantly to 0.76 (0.67-0.86, p=0.017) , whereas the manual per-patient calibration showed a diagnostic performance of 0.79 (0.70-0.89, p=0.01). In conclusion, the results show that an automated per-patient reference tissue PK model is feasible. A significantly better discriminating performance compared to the conventional general calibration was obtained and the diagnostic accuracy is similar to using manual per-patient calibration.

  11. Manganese-impregnated mesoporous silica nanoparticles for signal enhancement in MRI cell labelling studies

    NASA Astrophysics Data System (ADS)

    Guillet-Nicolas, Rmy; Laprise-Pelletier, Myriam; Nair, Mahesh M.; Chevallier, Pascale; Lagueux, Jean; Gossuin, Yves; Laurent, Sophie; Kleitz, Freddy; Fortin, Marc-Andr

    2013-11-01

    Mesoporous silica nanoparticles (MSNs) are used in drug delivery and cell tracking applications. As Mn2+ is already implemented as a ``positive'' cell contrast agent in preclinical imaging procedures (in the form of MnCl2 for neurological studies), the introduction of Mn in the porous network of MSNs would allow labelling cells and tracking them using MRI. These particles are in general internalized in endosomes, an acidic environment with high saline concentration. In addition, the available MSN porosity could also serve as a carrier to deliver medical/therapeutic substances through the labelled cells. In the present study, manganese oxide was introduced in the porous network of MCM-48 silica nanoparticles (Mn-M48SNs). The particles exhibit a narrow size distribution (~140 nm diam.) and high porosity (~60% vol.), which was validated after insertion of Mn. The resulting Mn-M48SNs were characterized by TEM, N2 physisorption, and XRD. Evidence was found with H2-TPR, and XPS characterization, that Mn(ii) is the main oxidation state of the paramagnetic species after suspension in water, most probably in the form of Mn-OOH. The colloidal stability as a function of time was confirmed by DLS in water, acetate buffer and cell culture medium. In NMR data, no significant evidence of Mn2+ leaching was found in Mn-M48SNs in acidic water (pH 6), up to 96 hours after suspension. High longitudinal relaxivity values of r1 = 8.4 mM-1 s-1 were measured at 60 MHz and 37 C, with the lowest relaxometric ratios (r2/r1 = 2) reported to date for a Mn-MSN system. Leukaemia cells (P388) were labelled with Mn-M48SNs and nanoparticle cell internalization was confirmed by TEM. Finally, MRI contrast enhancement provided by cell labelling with escalated incubation concentrations of Mn-M48SNs was quantified at 1 T. This study confirmed the possibility of efficiently confining Mn into M48SNs using incipient wetness, while maintaining an open porosity and relatively high pore volume. Because these Mn-labelled M48SNs express strong ``positive'' contrast media properties at low concentrations, they are potentially applicable for cell tracking and drug delivery methodologies.Mesoporous silica nanoparticles (MSNs) are used in drug delivery and cell tracking applications. As Mn2+ is already implemented as a ``positive'' cell contrast agent in preclinical imaging procedures (in the form of MnCl2 for neurological studies), the introduction of Mn in the porous network of MSNs would allow labelling cells and tracking them using MRI. These particles are in general internalized in endosomes, an acidic environment with high saline concentration. In addition, the available MSN porosity could also serve as a carrier to deliver medical/therapeutic substances through the labelled cells. In the present study, manganese oxide was introduced in the porous network of MCM-48 silica nanoparticles (Mn-M48SNs). The particles exhibit a narrow size distribution (~140 nm diam.) and high porosity (~60% vol.), which was validated after insertion of Mn. The resulting Mn-M48SNs were characterized by TEM, N2 physisorption, and XRD. Evidence was found with H2-TPR, and XPS characterization, that Mn(ii) is the main oxidation state of the paramagnetic species after suspension in water, most probably in the form of Mn-OOH. The colloidal stability as a function of time was confirmed by DLS in water, acetate buffer and cell culture medium. In NMR data, no significant evidence of Mn2+ leaching was found in Mn-M48SNs in acidic water (pH 6), up to 96 hours after suspension. High longitudinal relaxivity values of r1 = 8.4 mM-1 s-1 were measured at 60 MHz and 37 C, with the lowest relaxometric ratios (r2/r1 = 2) reported to date for a Mn-MSN system. Leukaemia cells (P388) were labelled with Mn-M48SNs and nanoparticle cell internalization was confirmed by TEM. Finally, MRI contrast enhancement provided by cell labelling with escalated incubation concentrations of Mn-M48SNs was quantified at 1 T. This study confirmed the possibility of efficiently confining Mn into M48SNs using incipient wetness

  12. Diagnostic efficacy of gadoxetic acid (Primovist)-enhanced MRI and spiral CT for a therapeutic strategy: comparison with intraoperative and histopathologic findings in focal liver lesions.

    PubMed

    Hammerstingl, Renate; Huppertz, Alexander; Breuer, Josy; Balzer, Thomas; Blakeborough, Anthony; Carter, Rick; Fust, Lluis Castells; Heinz-Peer, Gertraud; Judmaier, Werner; Laniado, Michael; Manfredi, Riccardo M; Mathieu, Didier G; Mller, Dieter; Mortel, Koenraad; Reimer, Peter; Reiser, Maximilian F; Robinson, Philip J; Shamsi, Kohkan; Strotzer, Michael; Taupitz, Matthias; Tombach, Bernd; Valeri, Gianluca; van Beers, Bernhard E; Vogl, Thomas J

    2008-03-01

    A multicenter study has been employed to evaluate the diagnostic efficacy of magnetic resonance imaging (MRI) using the new liver-specific contrast agent gadoxetic acid (Gd-EOB-DTPA, Primovist), as opposed to contrast-enhanced biphasic spiral computed tomography (CT), in the diagnosis of focal liver lesions, compared with a standard of reference (SOR). One hundred and sixty-nine patients with hepatic lesions eligible for surgery underwent Gd-EOB-DTPA-enhanced MRI as well as CT within 6 weeks. Pathologic evaluation of the liver specimen combined with intraoperative ultrasound established the SOR. Data sets were evaluated on-site (14 investigators) and off-site (three independent blinded readers). Gd-EOB-DTPA was well tolerated. Three hundred and two lesions were detected in 131 patients valid for analysis by SOR. The frequency of correctly detected lesions was significantly higher on Gd-EOB-DTPA-enhanced MRI compared with CT in the clinical evaluation [10.44%; 95% confidence interval (CI): 4.88, 16.0]. In the blinded reading there was a trend towards Gd-EOB-DTPA-enhanced MRI, not reaching statistical significance (2.14%; 95% CI: -4.32, 8.6). However, the highest rate of correctly detected lesions with a diameter below 1 cm was achieved by Gd-EOB-DTPA-enhanced MRI. Differential diagnosis was superior for Gd-EOB-DTPA-enhanced MRI (82.1%) versus CT (71.0%). A change in surgical therapy was documented in 19 of 131 patients (14.5%) post Gd-EOB-DTPA-enhanced MRI. Gd-EOB-DTPA-enhanced MRI was superior in the diagnosis and therapeutic management of focal liver lesions compared with CT. PMID:18058107

  13. Delayed gadolinium-enhanced MRI of the fibrocartilage disc of the temporomandibular joint a feasibility study

    PubMed Central

    Pittschieler, Elisabeth; Szomolanyi, Pavol; Schmid-Schwap, Martina; Weber, Michael; Egerbacher, Monika; Traxler, Hannes; Trattnig, Siegfried

    2014-01-01

    Objective To 1) test the feasibility of delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) at 3 T in the temporomandibular joint (TMJ) and 2) to determine the optimal delay for measurements of the TMJ disc after i.v. contrast agent (CA) administration. Design MRI of the right and left TMJ of six asymptomatic volunteers was performed at 3 T using a dedicated coil. 2D inversion recovery (2D-IR) sequences were performed at 4 time points covering 120minutes and 3D gradient-echo (3D GRE) dual flip-angle sequences were performed at 14 time points covering 130minutes after the administration of 0.2mmol/kg of Gd-diethylenetriamine pentaacetic acid ion (Gd-DTPA)2-, i.e., 0.4mL of Magnevist per kg body weight. Pair-wise tests were used to assess differences between pre-and post-contrast T1 values. Results 2D-IR sequences showed a statistically significant drop (p<0.001) in T1 values after i.v. CA administration. The T1 drop of 50% was reached 60minutes after bolus injection in the TMJ disc. The 3D GRE dual flip-angle sequences confirmed these results and show plateau of T1 after 60minutes. Conclusions T1(Gd) maps calculated from dGEMRIC data allow in vivo assessment of the fibrocartilage disc of the TMJ. The recommended measurement time for dGEMRIC in the TMJ after i.v. CA administration is from 60 to 120minutes. PMID:25131629

  14. Estimating kinetic parameter maps from dynamic contrast-enhanced MRI using spatial prior knowledge.

    PubMed

    Kelm, Bernd Michael; Menze, Bjoern H; Nix, Oliver; Zechmann, Christian M; Hamprecht, Fred A

    2009-10-01

    Dynamic contrast-enhanced magnetic resonance (DCE-MR) imaging can be used to study microvascular structure in vivo by monitoring the abundance of an injected diffusible contrast agent over time. The resulting spatially resolved intensity-time curves are usually interpreted in terms of kinetic parameters obtained by fitting a pharmacokinetic model to the observed data. Least squares estimates of the highly nonlinear model parameters, however, can exhibit high variance and can be severely biased. As a remedy, we bring to bear spatial prior knowledge by means of a generalized Gaussian Markov random field (GGMRF). By using information from neighboring voxels and computing the maximum a posteriori solution for entire parameter maps at once, both bias and variance of the parameter estimates can be reduced thus leading to smaller root mean square error (RMSE). Since the number of variables gets very big for common image resolutions, sparse solvers have to be employed. To this end, we propose a generalized iterated conditional modes (ICM) algorithm operating on blocks instead of sites which is shown to converge considerably faster than the conventional ICM algorithm. Results on simulated DCE-MR images show a clear reduction of RMSE and variance as well as, in some cases, reduced estimation bias. The mean residual bias (MRB) is reduced on the simulated data as well as for all 37 patients of a prostate DCE-MRI dataset. Using the proposed algorithm, average computation times only increase by a factor of 1.18 (871 ms per voxel) for a Gaussian prior and 1.51 (1.12 s per voxel) for an edge-preserving prior compared to the single voxel approach (740 ms per voxel). PMID:19369150

  15. Improved parameter extraction and classification for dynamic contrast enhanced MRI of prostate

    NASA Astrophysics Data System (ADS)

    Haq, Nandinee Fariah; Kozlowski, Piotr; Jones, Edward C.; Chang, Silvia D.; Goldenberg, S. Larry; Moradi, Mehdi

    2014-03-01

    Magnetic resonance imaging (MRI), particularly dynamic contrast enhanced (DCE) imaging, has shown great potential in prostate cancer diagnosis and prognosis. The time course of the DCE images provides measures of the contrast agent uptake kinetics. Also, using pharmacokinetic modelling, one can extract parameters from the DCE-MR images that characterize the tumor vascularization and can be used to detect cancer. A requirement for calculating the pharmacokinetic DCE parameters is estimating the Arterial Input Function (AIF). One needs an accurate segmentation of the cross section of the external femoral artery to obtain the AIF. In this work we report a semi-automatic method for segmentation of the cross section of the femoral artery, using circular Hough transform, in the sequence of DCE images. We also report a machine-learning framework to combine pharmacokinetic parameters with the model-free contrast agent uptake kinetic parameters extracted from the DCE time course into a nine-dimensional feature vector. This combination of features is used with random forest and with support vector machine classi cation for cancer detection. The MR data is obtained from patients prior to radical prostatectomy. After the surgery, wholemount histopathology analysis is performed and registered to the DCE-MR images as the diagnostic reference. We show that the use of a combination of pharmacokinetic parameters and the model-free empirical parameters extracted from the time course of DCE results in improved cancer detection compared to the use of each group of features separately. We also validate the proposed method for calculation of AIF based on comparison with the manual method.

  16. Mn-alginate gels as a novel system for controlled release of Mn2+ in manganese-enhanced MRI.

    PubMed

    Mrch, Yrr A; Sandvig, Ioanna; Olsen, Oystein; Donati, Ivan; Thuen, Marte; Skjk-Braek, Gudmund; Haraldseth, Olav; Brekken, Christian

    2012-01-01

    The aim of the present study was to test alginate gels of different compositions as a system for controlled release of manganese ions (Mn(2+)) for application in manganese-enhanced MRI (MEMRI), in order to circumvent the challenge of achieving optimal MRI resolution without resorting to high, potentially cytotoxic doses of Mn(2+). Elemental analysis and stability studies of Mn-alginate revealed marked differences in ion binding capacity, rendering Mn/Ba-alginate gels with high guluronic acid content most stable. The findings were corroborated by corresponding differences in the release rate of Mn(2+) from alginate beads in vitro using T(1)-weighted MRI. Furthermore, intravitreal (ivit) injection of Mn-alginate beads yielded significant enhancement of the rat retina and retinal ganglion cell (RGC) axons 24?h post-injection. Subsequent compartmental modelling and simulation of ivit Mn(2+) transport and concentration revealed that application of slow release contrast agents can achieve a significant reduction of ivit Mn(2+) concentration compared with bolus injection. This is followed by a concomitant increase in the availability of ivit Mn(2+) for uptake by RGC, corresponding to significantly increased time constants. Our results provide proof-of-concept for the applicability of Mn-alginate gels as a system for controlled release of Mn(2+) for optimized MEMRI application. PMID:22434640

  17. Detection of renal ischemic lesions using Gd-DTPA enhanced turbo FLASH MRI: Experimental and clinical results

    SciTech Connect

    Vosshenrich, R.; Fischer, U.; Funke, M.; Kopka, L.; Grabbe, E.

    1996-03-01

    Our goal was to investigate the role of Gd-DTPA-enhanced dynamic MRI in the evaluation of renal ischemic lesions. With a turbo FLASH sequence before and after injection of Gd-DTPA, nine foxhound dogs after 60-120 min of renal ischemia underwent MR examination. In addition, five patients with a tumor in a solitary kidney were examined before and after nephron-sparing renal surgery to evaluate renal perfusion and function. The experimental and clinical findings were correlated with conventional measurements of kidney function and with histological findings. Complete renal ischemia leads to a poor corticomedullary differentiation in Gd-DTPA-enhanced turbo FLASH MRI. The signal-intensity-versus-time plots of kidneys with significant postischemic changes show a less steep increase of signal intensity in the cortex and a steeper increase of signal intensity in the medulla than those of normal kidneys. Dynamic MRI demonstrate renal morphology and reflect the functional status of the renal vasculature. 21 refs., 8 figs., 1 tab.

  18. Suitability of Pharmacokinetic Models for Dynamic Contrast-Enhanced MRI of Abdominal Aortic Aneurysm Vessel Wall: A Comparison

    PubMed Central

    Nguyen, V. Lai; Kooi, M. Eline; Backes, Walter H.; van Hoof, Raf H. M.; Saris, Anne E. C. M.; Wishaupt, Mirthe C. J.; Hellenthal, Femke A. M. V. I.; van der Geest, Rob J.; Kessels, Alfons G. H.; Schurink, Geert Willem H.; Leiner, Tim

    2013-01-01

    Purpose Increased microvascularization of the abdominal aortic aneurysm (AAA) vessel wall has been related to AAA progression and rupture. The aim of this study was to compare the suitability of three pharmacokinetic models to describe AAA vessel wall enhancement using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Materials and Methods Patients with AAA underwent DCE-MRI at 1.5 Tesla. The volume transfer constant (Ktrans), which reflects microvascular flow, permeability and surface area, was calculated by fitting the blood and aneurysm vessel wall gadolinium concentration curves. The relative fit errors, parameter uncertainties and parameter reproducibilities for the Patlak, Tofts and Extended Tofts model were compared to find the most suitable model. Scan-rescan reproducibility was assessed using the interclass correlation coefficient and coefficient of variation (CV). Further, the relationship between Ktrans and AAA size was investigated. Results DCE-MRI examinations from thirty-nine patients (mean ageSD: 726 years; M/F: 35/4) with an mean AAA maximal diameter of 496 mm could be included for pharmacokinetic analysis. Relative fit uncertainties for Ktrans based on the Patlak model (17%) were significantly lower compared to the Tofts (37%) and Extended Tofts model (42%) (p<0.001). Ktrans scan-rescan reproducibility for the Patlak model (ICC?=?0.61 and CV?=?22%) was comparable with the Tofts (ICC?=?0.61, CV?=?23%) and Extended Tofts model (ICC?=?0.76, CV?=?22%). Ktrans was positively correlated with maximal AAA diameter (Spearmans ??=?0.38, p?=?0.02) using the Patlak model. Conclusion Using the presented imaging protocol, the Patlak model is most suited to describe DCE-MRI data of the AAA vessel wall with good Ktrans scan-rescan reproducibility. PMID:24098370

  19. Respiratory Motion-Compensated Radial Dynamic Contrast-Enhanced (DCE)-MRI of Chest and Abdominal Lesions

    PubMed Central

    Lin, Wei; Guo, Junyu; Rosen, Mark A.; Song, Hee Kwon

    2016-01-01

    Dynamic contrast-enhanced (DCE)-MRI is becoming an increasingly important tool for evaluating tumor vascularity and assessing the effectiveness of emerging antiangiogenic and antivascular agents. In chest and abdominal regions, however, respiratory motion can seriously degrade the achievable image quality in DCE-MRI studies. The purpose of this work is to develop a respiratory motion-compensated DCE-MRI technique that combines the self-gating properties of radial imaging with the reconstruction flexibility afforded by the golden-angle view-order strategy. Following radial data acquisition, the signal at k-space center is first used to determine the respiratory cycle, and consecutive views during the expiratory phase of each respiratory period (34–55 views, depending on the breathing rate) are grouped into individual segments. Residual intra-segment translation of lesion is subsequently compensated for by an autofocusing technique that optimizes image entropy, while intersegment translation (among different respiratory cycles) is corrected using 3D image correlation. The resulting motion-compensated, undersampled dynamic image series is then processed to reduce image streaking and to enhance the signal-to-noise ratio (SNR) prior to perfusion analysis, using either the k-space-weighted image contrast (KWIC) radial filtering technique or principal component analysis (PCA). The proposed data acquisition scheme also allows for high framerate arterial input function (AIF) sampling and free-breathing baseline T1 mapping. The performance of the proposed radial DCE-MRI technique is evaluated in subjects with lung and liver lesions, and results demonstrate that excellent pixelwise perfusion maps can be obtained with the proposed methodology. PMID:18956465

  20. Adaptive voxel, texture and temporal conditional random fields for detection of Gad-enhancing multiple sclerosis lesions in brain MRI.

    PubMed

    Karimaghaloo, Zahra; Rivaz, Hassan; Arnold, Douglas L; Collins, D Louis; Arbel, Tal

    2013-01-01

    The detection of Gad-enhancing lesions in brain MRI of Multiple Sclerosis (MS) patients is of great clinical interest since they are important markers of disease activity. However, many of the enhancing voxels are associated with normal structures (i.e. blood vessels) or noise in the MRI, making the detection of Gad-enhancing lesions a challenging task. Furthermore, these lesions are typically small and in close proximity to vessels. In this paper, we present a probabilistic Adaptive Multi-level Conditional Random Field (AMCRF) framework, capable of leveraging spatial and temporal information, for detection of MS Gad-enhancing lesions. In the first level, a voxel based CRF with cliques of up to size three, is used to identify candidate lesions. In the second level, higher order potentials are incorporated leveraging robust textural features which are invariant to rotation and local intensity distortions. Furthermore, we show how to exploit temporal and longitudinal images, should they be available, into the AMCRF model. The proposed algorithm is tested on 120 multimodal clinical datasets acquired from Relapsing-Remitting MS patients during multi-center clinical trials. Results show a sensitivity of 93%, a positive predictive value of 70% and average False Positive (FP) counts of 0.77. Moreover, the temporal AMCRF results show the same sensitivity as the AMCRF model while decreasing the FP counts by 22%. PMID:24505804

  1. An Unusual Case of Mammary Paget's Disease Diagnosed Using Dynamic Contrast-Enhanced MRI.

    PubMed

    Gaspari, Eleonora; Ricci, Aurora; Liberto, Valeria; Scarano, Angela Lia; Fornari, Maria; Simonetti, Giovanni

    2013-01-01

    Mammary Paget's disease is a rare presentation of breast cancer. At clinical examination, it is characterized by skin lesions of the nipple-areola complex, almost always a sign of malignancy. In fact, it is often associated with an underlying mammary ductal carcinoma in situ (DCIS) or invasive carcinoma. An underlying carcinoma is also common in women with negative mammography and ultrasound (US); in these cases, magnetic resonance imaging (MRI) is a diagnostic tool useful in the detection of occult cancer. We described an unusual case of mammary Paget's disease with underlying DCIS, in a patient without nipple-areola complex alterations and/or palpable lump. On suspicion of Paget's disease, the patient underwent MRI examination that proved useful for an accurate diagnosis. Biopsy confirmed dynamic MRI findings. PMID:23607031

  2. fMRI neurofeedback of amygdala response to aversive stimuli enhances prefrontal-limbic brain connectivity.

    PubMed

    Paret, Christian; Ruf, Matthias; Gerchen, Martin Fungisai; Kluetsch, Rosemarie; Demirakca, Traute; Jungkunz, Martin; Bertsch, Katja; Schmahl, Christian; Ende, Gabriele

    2016-01-15

    Down-regulation of the amygdala with real-time fMRI neurofeedback (rtfMRI NF) potentially allows targeting brain circuits of emotion processing and may involve prefrontal-limbic networks underlying effective emotion regulation. Little research has been dedicated to the effect of rtfMRI NF on the functional connectivity of the amygdala and connectivity patterns in amygdala down-regulation with neurofeedback have not been addressed yet. Using psychophysiological interaction analysis of fMRI data, we present evidence that voluntary amygdala down-regulation by rtfMRI NF while viewing aversive pictures was associated with increased connectivity of the right amygdala with the ventromedial prefrontal cortex (vmPFC) in healthy subjects (N=16). In contrast, a control group (N=16) receiving sham feedback did not alter amygdala connectivity (GroupCondition t-contrast: p<.05 at cluster-level). Task-dependent increases in amygdala-vmPFC connectivity were predicted by picture arousal (?=.59, p<.05). A dynamic causal modeling analysis with Bayesian model selection aimed at further characterizing the underlying causal structure and favored a bottom-up model assuming predominant information flow from the amygdala to the vmPFC (xp=.90). The results were complemented by the observation of task-dependent alterations in functional connectivity of the vmPFC with the visual cortex and the ventrolateral PFC in the experimental group (Condition t-contrast: p<.05 at cluster-level). Taken together, the results underscore the potential of amygdala fMRI neurofeedback to influence functional connectivity in key networks of emotion processing and regulation. This may be beneficial for patients suffering from severe emotion dysregulation by improving neural self-regulation. PMID:26481674

  3. The role of MRI in the diagnosis of multiple sclerosis.

    PubMed

    Traboulsee, Anthony L; Li, David K B

    2006-01-01

    There is no single test that is diagnostic of MS, including MRI. The lesions detected with MRI are pathologically nonspecific. The principles of MS diagnosis are based on showing dissemination of white matter lesions in space and time. MRI is the most sensitive method for revealing asymptomatic dissemination of lesions in space and time. The pattern and evolution of MRI lesions, in the appropriate clinical setting, has made MRI abnormalities invaluable criteria for the early diagnosis of MS. The first important role for MRI in the diagnosis of MS allows for an early diagnosis of MS for CIS patients using the IP diagnostic criteria, including MRI for dissemination in space (DIS) and time (DIT). The sensitivity of diagnosing MS within the first year after a single attack is 94%, with a specificity of 83%. The MRI evidence required to support the diagnosis varies, depending on the strength of the clinical findings. Allowing a new MRI lesion to substitute for a clinical attack doubles the number of CIS patients who can be diagnosed as having MS within 1 year of symptom onset. Increasing the sensitivity of the test with more lenient criteria, as recommended by the AAN subcommittee, can result in decreased specificity. The second important role for MRI in the diagnostic work-up of suspected MS patients is to rule out alternative diagnoses obvious on MRI, such as spinal stenosis and most brain tumors. Characteristic lesions that favor MS include Dawson Fingers, ovoid lesions, corpus callosum lesions, and asymptomatic spinal cord lesions. However, other white matter diseases can have similar appearances on MRI. Persistent gadolinium enhancement greater than three months, lesions with mass effect, and meningeal enhancement suggest other disorders. A standardized MRI protocol for brain and spinal cord is crucial for comparing across studies or between centers. T2W MRI cannot distinguish between acute and chronic lesions. Gadolinium provides useful information about new lesion activity and is helpful in ruling out alternative diagnoses such as neoplasm, vascular malformations, and leptomeningeal disease. A single gadolinium-enhanced MRI can potentially provide evidence for dissemination in space and time. Spinal cord imaging is equally valuable to rule out spinal stenosis or tumor, and for detecting asymptomatic lesions when brain imaging is nondiagnostic in patients suspected of having MS. Precise criteria may be too suggestive that MS can be diagnosed by MRI and a negative MRI at the time of CIS does not rule out MS. MRI evidence plays a supportive role in what is ultimately a clinical diagnosis of MS, in the appropriate clinical situation, and always at the exclusion of alternative diagnoses. PMID:16400831

  4. Enhanced control of dorsolateral prefrontal cortex neurophysiology with real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback training and working memory practice.

    PubMed

    Sherwood, Matthew S; Kane, Jessica H; Weisend, Michael P; Parker, Jason G

    2016-01-01

    Real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback can be used to train localized, conscious regulation of blood oxygen level-dependent (BOLD) signals. As a therapeutic technique, rt-fMRI neurofeedback reduces the symptoms of a variety of neurologic disorders. To date, few studies have investigated the use of self-regulation training using rt-fMRI neurofeedback to enhance cognitive performance. This work investigates the utility of rt-fMRI neurofeedback as a tool to enhance human cognition by training healthy individuals to consciously control activity in the left dorsolateral prefrontal cortex (DLPFC). A cohort of 18 healthy participants in the experimental group underwent rt-fMRI neurofeedback from the left DLPFC in five training sessions across two weeks while 7 participants in the control group underwent similar training outside the MRI and without rt-fMRI neurofeedback. Working memory (WM) performance was evaluated on two testing days separated by the five rt-fMRI neurofeedback sessions using two computerized tests. We investigated the ability to control the BOLD signal across training sessions and WM performance across the two testing days. The group with rt-fMRI neurofeedback demonstrated a significant increase in the ability to self-regulate the BOLD signal in the left DLPFC across sessions. WM performance showed differential improvement between testing days one and two across the groups with the highest increases observed in the rt-fMRI neurofeedback group. These results provide evidence that individuals can quickly gain the ability to consciously control the left DLPFC, and this training results in improvements of WM performance beyond that of training alone. PMID:26348555

  5. Preliminary Study of Oxygen-Enhanced Longitudinal Relaxation in MRI: A Potential Novel Biomarker of Oxygenation Changes in Solid Tumors

    SciTech Connect

    O'Connor, James P.B.; Naish, Josephine H.; Parker, Geoff J.M.; Waterton, John C.; Watson, Yvonne; Jayson, Gordon C.; Buonaccorsi, Giovanni A.; Cheung, Sue; Buckley, David L.; McGrath, Deirdre M.; West, Catharine M.L.; Davidson, Susan E.; Roberts, Caleb; Mills, Samantha J.; Mitchell, Claire L.; Hope, Lynn; Ton, N. Chan; Jackson, Alan

    2009-11-15

    Purpose: There is considerable interest in developing non-invasive methods of mapping tumor hypoxia. Changes in tissue oxygen concentration produce proportional changes in the magnetic resonance imaging (MRI) longitudinal relaxation rate (R{sub 1}). This technique has been used previously to evaluate oxygen delivery to healthy tissues and is distinct from blood oxygenation level-dependent (BOLD) imaging. Here we report application of this method to detect alteration in tumor oxygenation status. Methods and materials: Ten patients with advanced cancer of the abdomen and pelvis underwent serial measurement of tumor R{sub 1} while breathing medical air (21% oxygen) followed by 100% oxygen (oxygen-enhanced MRI). Gadolinium-based dynamic contrast-enhanced MRI was then performed to compare the spatial distribution of perfusion with that of oxygen-induced DELTAR{sub 1}. Results: DELTAR{sub 1} showed significant increases of 0.021 to 0.058 s{sup -1} in eight patients with either locally recurrent tumor from cervical and hepatocellular carcinomas or metastases from ovarian and colorectal carcinomas. In general, there was congruency between perfusion and oxygen concentration. However, regional mismatch was observed in some tumor cores. Here, moderate gadolinium uptake (consistent with moderate perfusion) was associated with low area under the DELTAR{sub 1} curve (consistent with minimal increase in oxygen concentration). Conclusions: These results provide evidence that oxygen-enhanced longitudinal relaxation can monitor changes in tumor oxygen concentration. The technique shows promise in identifying hypoxic regions within tumors and may enable spatial mapping of change in tumor oxygen concentration.

  6. Retrieval of brain tumors with region-specific bag-of-visual-words representations in contrast-enhanced MRI images.

    PubMed

    Huang, Meiyan; Yang, Wei; Yu, Mei; Lu, Zhentai; Feng, Qianjin; Chen, Wufan

    2012-01-01

    A content-based image retrieval (CBIR) system is proposed for the retrieval of T1-weighted contrast-enhanced MRI (CE-MRI) images of brain tumors. In this CBIR system, spatial information in the bag-of-visual-words model and domain knowledge on the brain tumor images are considered for the representation of brain tumor images. A similarity metric is learned through a distance metric learning algorithm to reduce the gap between the visual features and the semantic concepts in an image. The learned similarity metric is then used to measure the similarity between two images and then retrieve the most similar images in the dataset when a query image is submitted to the CBIR system. The retrieval performance of the proposed method is evaluated on a brain CE-MRI dataset with three types of brain tumors (i.e., meningioma, glioma, and pituitary tumor). The experimental results demonstrate that the mean average precision values of the proposed method range from 90.4% to 91.5% for different views (transverse, coronal, and sagittal) with an average value of 91.0%. PMID:23243462

  7. Retrieval of Brain Tumors with Region-Specific Bag-of-Visual-Words Representations in Contrast-Enhanced MRI Images

    PubMed Central

    Huang, Meiyan; Yang, Wei; Yu, Mei; Lu, Zhentai; Feng, Qianjin; Chen, Wufan

    2012-01-01

    A content-based image retrieval (CBIR) system is proposed for the retrieval of T1-weighted contrast-enhanced MRI (CE-MRI) images of brain tumors. In this CBIR system, spatial information in the bag-of-visual-words model and domain knowledge on the brain tumor images are considered for the representation of brain tumor images. A similarity metric is learned through a distance metric learning algorithm to reduce the gap between the visual features and the semantic concepts in an image. The learned similarity metric is then used to measure the similarity between two images and then retrieve the most similar images in the dataset when a query image is submitted to the CBIR system. The retrieval performance of the proposed method is evaluated on a brain CE-MRI dataset with three types of brain tumors (i.e., meningioma, glioma, and pituitary tumor). The experimental results demonstrate that the mean average precision values of the proposed method range from 90.4% to 91.5% for different views (transverse, coronal, and sagittal) with an average value of 91.0%. PMID:23243462

  8. Permeability assessment of the focused ultrasound-induced blood-brain barrier opening using dynamic contrast-enhanced MRI

    NASA Astrophysics Data System (ADS)

    Vlachos, F.; Tung, Y.-S.; Konofagou, E. E.

    2010-09-01

    Focused ultrasound (FUS) in conjunction with microbubbles has been shown to successfully open the blood-brain barrier (BBB) in the mouse brain. In this study, we compute the BBB permeability after opening in vivo. The spatial permeability of the BBB-opened region was assessed using dynamic contrast-enhanced MRI (DCE-MRI). The DCE-MR images were post-processed using the general kinetic model (GKM) and the reference region model (RRM). Permeability maps were generated and the Ktrans values were calculated for a predefined volume of interest in the sonicated and the control area for each mouse. The results demonstrated that Ktrans in the BBB-opened region (0.02 ± 0.0123 for GKM and 0.03 ± 0.0167 min-1 for RRM) was at least two orders of magnitude higher when compared to the contra-lateral (control) side (0 and 8.5 × 10-4 ± 12 × 10-4 min-1, respectively). The permeability values obtained with the two models showed statistically significant agreement and excellent correlation (R2 = 0.97). At histological examination, it was concluded that no macroscopic damage was induced. This study thus constitutes the first permeability assessment of FUS-induced BBB opening using DCE-MRI, supporting the fact that the aforementioned technique may constitute a safe, non-invasive and efficacious drug delivery method.

  9. Permeability assessment of the focused ultrasound-induced blood-brain barrier opening using dynamic contrast-enhanced MRI.

    PubMed

    Vlachos, F; Tung, Y-S; Konofagou, E E

    2010-09-21

    Focused ultrasound (FUS) in conjunction with microbubbles has been shown to successfully open the blood-brain barrier (BBB) in the mouse brain. In this study, we compute the BBB permeability after opening in vivo. The spatial permeability of the BBB-opened region was assessed using dynamic contrast-enhanced MRI (DCE-MRI). The DCE-MR images were post-processed using the general kinetic model (GKM) and the reference region model (RRM). Permeability maps were generated and the K(trans) values were calculated for a predefined volume of interest in the sonicated and the control area for each mouse. The results demonstrated that K(trans) in the BBB-opened region (0.02 +/- 0.0123 for GKM and 0.03 +/- 0.0167 min(-1) for RRM) was at least two orders of magnitude higher when compared to the contra-lateral (control) side (0 and 8.5 x 10(-4) +/- 12 x 10(-4) min(-1), respectively). The permeability values obtained with the two models showed statistically significant agreement and excellent correlation (R(2) = 0.97). At histological examination, it was concluded that no macroscopic damage was induced. This study thus constitutes the first permeability assessment of FUS-induced BBB opening using DCE-MRI, supporting the fact that the aforementioned technique may constitute a safe, non-invasive and efficacious drug delivery method. PMID:20736501

  10. Quantitative Estimation of Renal Function with Dynamic Contrast-Enhanced MRI Using a Modified Two-Compartment Model

    PubMed Central

    Chen, Bin; Zhang, Yudong; Song, Xiaojian; Wang, Xiaoying; Zhang, Jue; Fang, Jing

    2014-01-01

    Objective To establish a simple two-compartment model for glomerular filtration rate (GFR) and renal plasma flow (RPF) estimations by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Materials and Methods A total of eight New Zealand white rabbits were included in DCE-MRI. The two-compartment model was modified with the impulse residue function in this study. First, the reliability of GFR measurement of the proposed model was compared with other published models in Monte Carlo simulation at different noise levels. Then, functional parameters were estimated in six healthy rabbits to test the feasibility of the new model. Moreover, in order to investigate its validity of GFR estimation, two rabbits underwent acute ischemia surgical procedure in unilateral kidney before DCE-MRI, and pixel-wise measurements were implemented to detect the cortical GFR alterations between normal and abnormal kidneys. Results The lowest variability of GFR and RPF measurements were found in the proposed model in the comparison. Mean GFR was 3.031.1 ml/min and mean RPF was 2.640.5 ml/g/min in normal animals, which were in good agreement with the published values. Moreover, large GFR decline was found in dysfunction kidneys comparing to the contralateral control group. Conclusion Results in our study demonstrate that measurement of renal kinetic parameters based on the proposed model is feasible and it has the ability to discriminate GFR changes in healthy and diseased kidneys. PMID:25141138

  11. A dimensionless dynamic contrast enhanced MRI parameter for intra-prostatic tumour target volume delineation: initial comparison with histology

    NASA Astrophysics Data System (ADS)

    Hrinivich, W. Thomas; Gibson, Eli; Gaed, Mena; Gomez, Jose A.; Moussa, Madeleine; McKenzie, Charles A.; Bauman, Glenn S.; Ward, Aaron D.; Fenster, Aaron; Wong, Eugene

    2014-03-01

    Purpose: T2 weighted and diffusion weighted magnetic resonance imaging (MRI) show promise in isolating prostate tumours. Dynamic contrast enhanced (DCE)-MRI has also been employed as a component in multi-parametric tumour detection schemes. Model-based parameters such as Ktrans are conventionally used to characterize DCE images and require arterial contrast agent (CR) concentration. A robust parameter map that does not depend on arterial input may be more useful for target volume delineation. We present a dimensionless parameter (Wio) that characterizes CR wash-in and washout rates without requiring arterial CR concentration. Wio is compared to Ktrans in terms of ability to discriminate cancer in the prostate, as demonstrated via comparison with histology. Methods: Three subjects underwent DCE-MRI using gadolinium contrast and 7 s imaging temporal resolution. A pathologist identified cancer on whole-mount histology specimens, and slides were deformably registered to MR images. The ability of Wio maps to discriminate cancer was determined through receiver operating characteristic curve (ROC) analysis. Results: There is a trend that Wio shows greater area under the ROC curve (AUC) than Ktrans with median AUC values of 0.74 and 0.69 respectively, but the difference was not statistically significant based on a Wilcoxon signed-rank test (p = 0.13). Conclusions: Preliminary results indicate that Wio shows potential as a tool for Ktrans QA, showing similar ability to discriminate cancer in the prostate as Ktrans without requiring arterial CR concentration.

  12. Quantification of Massive Allograft Healing with Dynamic Contrast Enhanced-MRI and Cone Beam-CT: A Pilot Study

    PubMed Central

    Ehrhart, Nicole; Kraft, Susan; Conover, David; Rosier, Randy N.

    2008-01-01

    Although massive allografts are widely used for reconstruction of critical defects in long bones caused by tumor or trauma, many will have inadequate long-term outcomes. Toward a tissue engineering solution to this problem, we developed experimental stem cell and gene therapy adjuvants that induce angiogenesis, osteogenesis, and remodeling of the structural allografts. We present data from pilot studies to show the utility of dynamic contrast enhanced MRI (DCE-MRI) to quantify vascularity after femoral osteotomy in a canine femur model and cone beam CT (CB-CT) to quantify bone volume in a patient after composite prosthetic-allograft reconstructive surgery. The results demonstrate our ability to suppress the artifacts generated by the metal implants required to secure massive allografts such that precise quantification of cortical bone revascularization (>10-fold increase at 3weeks postoperatively) and new bone formation (accurate to about 193?m3) around the graft can be performed longitudinally via DCE-MRI and CB-CT, respectively. PMID:18543052

  13. Application of dynamic MRI to differentiating odontogenic myxomas from ameloblastomas.

    PubMed

    Asaumi, Jun-ichi; Matsuzaki, Hidenobu; Hisatomi, Miki; Konouchi, Hironobu; Shigehara, Hiroshi; Kishi, Kanji

    2002-07-01

    It is often difficult to radiographically distinguish odontogenic myxomas from ameloblastomas. In the present study, we tried to differentiate odontogenic myxomas from ameloblastomas using dynamic magnetic resonance imaging (dynamic MRI). Two cases of ameloblastoma with cystic components and two cases of odontogenic myxoma were compared by dynamic MRI. The dynamic MRI features of solid areas of ameloblastomas showed a rapid enhancement, reaching maximum contrast at 45-60 s, and maintained these enhancement levels or showed a gradual wash-out to 600 s thereafter; in contrast, those of the cystic areas of ameloblastomas showed no enhancement. The dynamic MRI features of the whole area of odontogenic myxomas (we considered the whole area to be the tumor substance in the odontogenic myxomas, as based on histopathological examinations) showed a gradual increase in enhancement at 500-600 s. The central portions of the odontogenic myxomas, which did not appear to be enhanced on Gd-T1 weighted images also showed a gradual increase in enhancement at 500-600 s, though the increase was minimal. These results indicate that the dynamic MRI features of odontogenic myxomas are different from those of ameloblastomas. Therefore, dynamic MRI may be a useful tool for diagnosis of myxoma. PMID:12065119

  14. Dynamic contrast-enhanced MRI serves as a predictor of HIFU treatment outcome for uterine fibroids with hyperintensity in T2-weighted images

    PubMed Central

    ZHAO, WEN-PENG; CHEN, JIN-YUN; CHEN, WEN-ZHI

    2016-01-01

    The aim of the present study was to investigate the efficacy of dynamic contrast-enhanced magnetic resonance imaging (MRI) in predicting the outcome of using ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation for the treatment of uterine fibroids with T2 hyperintensity under MRI. A total of 131 uterine fibroids from 131 patients that appeared hyperintense under T2-weighted MRI were analyzed. The uterine fibroids were subjectively categorized into slight, irregular or regular enhancement groups, according to pretreatment dynamic contrast-enhanced MRI in the arterial phase within 60 sec after the injection of gadolinium. The non-perfused volume (NPV), which is indicative of successful ablation, was represented as the non-perfused area inside the uterine fibroids on enhanced MRI scans following treatment. Additionally, the treatment duration, treatment efficiency, sonication duration, energy efficiency ratio and any adverse events were recorded. The results indicated that the average NPV ratio for all the treated fibroids was 68.5%, while the average NPV ratios for fibroids with slight, irregular or regular enhancement were 84.7, 70.6 and 57.1%, respectively. Fibroids with regular enhancement were associated with the lowest NPV ratio and the lowest treatment efficiency, but exhibited the highest energy effect ratio and an elevated risk of severe adverse effects. The results of the present study indicate that hyperintense uterine fibroids with slight and irregular enhancement in the arterial phase of dynamic contrast-enhanced MRI are suitable for USgHIFU treatment. By contrast, uterine fibroids with regular enhancement were associated with the lowest treatment efficacy and safety. PMID:26889263

  15. Multimodal visualization of 3D enhanced MRI and CT of acoustic schwannoma and related structures

    NASA Astrophysics Data System (ADS)

    Kucharski, Tomasz; Kujawinska, Malgorzata; Niemczyk, Kazimierz; Marchel, Andrzej

    2005-09-01

    According to the necessity of supporting vestibular schwannoma surgery, there is a demand to develop a convenient method of medical data visualization. The process of making choice of optimal operating access way has been uncomfortable for a surgeon so far, because there has been a necessity of analyzing two independent 3D images series (CT -bone tissues visible, MRI - soft tissues visible) in the region of ponto-cerebellar angle tumors. The authors propose a solution that will improve this process. The system used is equipped with stereoscopic helmet mounted display. It allows merged CT and MRI data representing tissues in the region of of ponto-cerebellar angle to be visualized in stereoscopic way. The process of data preparation for visualization includes: -automated segmentation algorithms, -different types of 3D images (CT, MRI) fusion. The authors focused on the development of novel algorithms for segmentation of vestibular schwannoma. It is important and difficult task due to different types of tumors and their inhomogeneous character dependent on growth models. The authors propose algorithms based on histogram spectrum and multimodal character of MRI imaging (T1 and T2 modes). However due to a variety of objects the library of algorithms with specific modifications matching to selected types of images is proposed. The applicability and functionality of the algorithms and library was proved on the series of data delivered by Warsaw Central Medical University Hospital.

  16. Enhancing 4D PC-MRI in an aortic phantom considering numerical simulations

    NASA Astrophysics Data System (ADS)

    Kratzke, Jonas; Schoch, Nicolai; Weis, Christian; Mller-Eschner, Matthias; Speidel, Stefanie; Farag, Mina; Beller, Carsten J.; Heuveline, Vincent

    2015-03-01

    To date, cardiovascular surgery enables the treatment of a wide range of aortic pathologies. One of the current challenges in this field is given by the detection of high-risk patients for adverse aortic events, who should be treated electively. Reliable diagnostic parameters, which indicate the urge of treatment, have to be determined. Functional imaging by means of 4D phase contrast-magnetic resonance imaging (PC-MRI) enables the time-resolved measurement of blood flow velocity in 3D. Applied to aortic phantoms, three dimensional blood flow properties and their relation to adverse dynamics can be investigated in vitro. Emerging "in silico" methods of numerical simulation can supplement these measurements in computing additional information on crucial parameters. We propose a framework that complements 4D PC-MRI imaging by means of numerical simulation based on the Finite Element Method (FEM). The framework is developed on the basis of a prototypic aortic phantom and validated by 4D PC-MRI measurements of the phantom. Based on physical principles of biomechanics, the derived simulation depicts aortic blood flow properties and characteristics. The framework might help identifying factors that induce aortic pathologies such as aortic dilatation or aortic dissection. Alarming thresholds of parameters such as wall shear stress distribution can be evaluated. The combined techniques of 4D PC-MRI and numerical simulation can be used as complementary tools for risk-stratification of aortic pathology.

  17. Pharmacokinetic Changes Induced by Focused Ultrasound in Glioma-Bearing Rats as Measured by Dynamic Contrast-Enhanced MRI

    PubMed Central

    Yang, Feng-Yi; Ko, Chia-En; Huang, Sheng-Yao; Chung, I-Fang; Chen, Gin-Shin

    2014-01-01

    Focused ultrasound (FUS) combined with microbubbles has been shown to be a noninvasive and targeted drug delivery technique for brain tumor treatment. The purpose of this study was to measure the kinetics of Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) in glioma-bearing rats in the presence of FUS-induced blood-brain barrier disruption (BBB-D) by magnetic resonance imaging (MRI). A total of ten glioma-bearing rats (9–12 weeks, 290–340 g) were used in this study. Using dynamic contrast-enhanced (DCE)-MRI, the spatial permeability of FUS-induced BBB-D was evaluated and the kinetic parameters were calculated by a general kinetic model (GKM). The results demonstrate that the mean Ktrans of the sonicated tumor (0.128±0.019 at 20 min and 0.103±0.023 at 24 h after sonication, respectively) was significantly higher than (2.46-fold at 20 min and 1.78-fold at 24 h) that of the contralateral (non-sonicated) tumor (0.052±0.019 at 20 min and 0.058±0.012 at 24 h after sonication, respectively). In addition, the transfer constant Ktrans in the sonicated tumor correlated strongly with tissue EB extravasation (R = 0.95), which suggests that DCE-MRI may reflect drug accumulation in the brain. Histological observations showed no macroscopic damage except for a few small erythrocyte extravasations. The current study demonstrates that DCE-MRI can monitor the dynamics of the FUS-induced BBB-D process and constitutes a useful tool for quantifying BBB permeability in tumors. PMID:24670992

  18. Pharmacokinetic changes induced by focused ultrasound in glioma-bearing rats as measured by dynamic contrast-enhanced MRI.

    PubMed

    Yang, Feng-Yi; Ko, Chia-En; Huang, Sheng-Yao; Chung, I-Fang; Chen, Gin-Shin

    2014-01-01

    Focused ultrasound (FUS) combined with microbubbles has been shown to be a noninvasive and targeted drug delivery technique for brain tumor treatment. The purpose of this study was to measure the kinetics of Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) in glioma-bearing rats in the presence of FUS-induced blood-brain barrier disruption (BBB-D) by magnetic resonance imaging (MRI). A total of ten glioma-bearing rats (9-12 weeks, 290-340 g) were used in this study. Using dynamic contrast-enhanced (DCE)-MRI, the spatial permeability of FUS-induced BBB-D was evaluated and the kinetic parameters were calculated by a general kinetic model (GKM). The results demonstrate that the mean Ktrans of the sonicated tumor (0.1280.019 at 20 min and 0.1030.023 at 24 h after sonication, respectively) was significantly higher than (2.46-fold at 20 min and 1.78-fold at 24 h) that of the contralateral (non-sonicated) tumor (0.0520.019 at 20 min and 0.0580.012 at 24 h after sonication, respectively). In addition, the transfer constant Ktrans in the sonicated tumor correlated strongly with tissue EB extravasation (R?=?0.95), which suggests that DCE-MRI may reflect drug accumulation in the brain. Histological observations showed no macroscopic damage except for a few small erythrocyte extravasations. The current study demonstrates that DCE-MRI can monitor the dynamics of the FUS-induced BBB-D process and constitutes a useful tool for quantifying BBB permeability in tumors. PMID:24670992

  19. Enhancing Motor Network Activity Using Real-Time Functional MRI Neurofeedback of Left Premotor Cortex.

    PubMed

    Marins, Theo F; Rodrigues, Erika C; Engel, Annerose; Hoefle, Sebastian; Baslio, Rodrigo; Lent, Roberto; Moll, Jorge; Tovar-Moll, Fernanda

    2015-01-01

    Neurofeedback by functional magnetic resonance imaging (fMRI) is a technique of potential therapeutic relevance that allows individuals to be aware of their own neurophysiological responses and to voluntarily modulate the activity of specific brain regions, such as the premotor cortex (PMC), important for motor recovery after brain injury. We investigated (i) whether healthy human volunteers are able to up-regulate the activity of the left PMC during a right hand finger tapping motor imagery (MI) task while receiving continuous fMRI-neurofeedback, and (ii) whether successful modulation of brain activity influenced non-targeted motor control regions. During the MI task, participants of the neurofeedback group (NFB) received ongoing visual feedback representing the level of fMRI responses within their left PMC. Control (CTL) group participants were shown similar visual stimuli, but these were non-contingent on brain activity. Both groups showed equivalent levels of behavioral ratings on arousal and MI, before and during the fMRI protocol. In the NFB, but not in CLT group, brain activation during the last run compared to the first run revealed increased activation in the left PMC. In addition, the NFB group showed increased activation in motor control regions extending beyond the left PMC target area, including the supplementary motor area, basal ganglia and cerebellum. Moreover, in the last run, the NFB group showed stronger activation in the left PMC/inferior frontal gyrus when compared to the CTL group. Our results indicate that modulation of PMC and associated motor control areas can be achieved during a single neurofeedback-fMRI session. These results contribute to a better understanding of the underlying mechanisms of MI-based neurofeedback training, with direct implications for rehabilitation strategies in severe brain disorders, such as stroke. PMID:26733832

  20. Enhancing Motor Network Activity Using Real-Time Functional MRI Neurofeedback of Left Premotor Cortex

    PubMed Central

    Marins, Theo F.; Rodrigues, Erika C.; Engel, Annerose; Hoefle, Sebastian; Basílio, Rodrigo; Lent, Roberto; Moll, Jorge; Tovar-Moll, Fernanda

    2015-01-01

    Neurofeedback by functional magnetic resonance imaging (fMRI) is a technique of potential therapeutic relevance that allows individuals to be aware of their own neurophysiological responses and to voluntarily modulate the activity of specific brain regions, such as the premotor cortex (PMC), important for motor recovery after brain injury. We investigated (i) whether healthy human volunteers are able to up-regulate the activity of the left PMC during a right hand finger tapping motor imagery (MI) task while receiving continuous fMRI-neurofeedback, and (ii) whether successful modulation of brain activity influenced non-targeted motor control regions. During the MI task, participants of the neurofeedback group (NFB) received ongoing visual feedback representing the level of fMRI responses within their left PMC. Control (CTL) group participants were shown similar visual stimuli, but these were non-contingent on brain activity. Both groups showed equivalent levels of behavioral ratings on arousal and MI, before and during the fMRI protocol. In the NFB, but not in CLT group, brain activation during the last run compared to the first run revealed increased activation in the left PMC. In addition, the NFB group showed increased activation in motor control regions extending beyond the left PMC target area, including the supplementary motor area, basal ganglia and cerebellum. Moreover, in the last run, the NFB group showed stronger activation in the left PMC/inferior frontal gyrus when compared to the CTL group. Our results indicate that modulation of PMC and associated motor control areas can be achieved during a single neurofeedback-fMRI session. These results contribute to a better understanding of the underlying mechanisms of MI-based neurofeedback training, with direct implications for rehabilitation strategies in severe brain disorders, such as stroke. PMID:26733832

  1. Pretreatment Dynamic Contrast-Enhanced MRI Improves Prediction of Early Distant Metastases in Patients With Nasopharyngeal Carcinoma

    PubMed Central

    Chin, Shy-Chyi; Lin, Chien-Yu; Huang, Bing-Shen; Tsang, Ngan-Ming; Fan, Kang-Hsing; Ku, Yi-Kang; Hsu, Cheng-Lung; Chan, Sheng-Chieh; Huang, Shiang-Fu; Li, Cheng-He; Tseng, Hsiao-Jung; Liao, Chun-Ta; Liu, Ho-Ling; Sung, Kyunghyun

    2016-01-01

    Abstract The identification of early distant metastases (DM) in patients with newly diagnosed, previously untreated nasopharyngeal carcinoma (NPC) plays an important role in selecting the most appropriate treatment approach. Here, we sought to investigate the predictive value of distinct MRI parameters for the detection of early DM. Between November 2010 and June 2011, a total of 51 newly diagnosed NPC patients were included. All of the study participants were followed until December 2014 at a single institution after completion of therapy. DM was defined as early when they were detected on pretreatment FDG-PET scans or within 6 months after initial diagnosis. The following parameters were tested for their ability to predict early DM: pretreatment FDG-PET standardized uptake value (SUV), MRI-derived AJCC tumor staging, tumor volume, and dynamic contrast-enhanced (DCE) values. The DCE-derived ve was defined as the volume fraction of the extravascular, extracellular space. Compared with patients without early DM, patients with early DM had higher SUV, tumor volume, DCE mean (median) ve, ve skewness, ve kurtosis, and the largest mean ve selected among sequential slices (P < 0.05). No differences were identified when early DM were defined only according to the results of pretreatment FDG-PET. Among different quantitative DCE parameters, the mean ve had the highest area under curve (AUC, 0.765). However, the AUCs of SUV, tumor volume, mean ve, ve skewness, ve kurtosis, or the largest mean ve selected among the sequential slices did not differ significantly from one another (P = 0.82). Taken together, our results suggest that DCE-derived ve may be a useful parameter in combination with SUV and tumor volume for predicting early DM. Dynamic contrast-enhanced MRI may be complementary to FDG-PET for selecting the most appropriate treatment approach in NPC patients. PMID:26871776

  2. Pretreatment Dynamic Contrast-Enhanced MRI Improves Prediction of Early Distant Metastases in Patients With Nasopharyngeal Carcinoma.

    PubMed

    Chin, Shy-Chyi; Lin, Chien-Yu; Huang, Bing-Shen; Tsang, Ngan-Ming; Fan, Kang-Hsing; Ku, Yi-Kang; Hsu, Cheng-Lung; Chan, Sheng-Chieh; Huang, Shiang-Fu; Li, Cheng-He; Tseng, Hsiao-Jung; Liao, Chun-Ta; Liu, Ho-Ling; Sung, Kyunghyun

    2016-02-01

    The identification of early distant metastases (DM) in patients with newly diagnosed, previously untreated nasopharyngeal carcinoma (NPC) plays an important role in selecting the most appropriate treatment approach. Here, we sought to investigate the predictive value of distinct MRI parameters for the detection of early DM.Between November 2010 and June 2011, a total of 51 newly diagnosed NPC patients were included. All of the study participants were followed until December 2014 at a single institution after completion of therapy. DM was defined as early when they were detected on pretreatment FDG-PET scans or within 6 months after initial diagnosis. The following parameters were tested for their ability to predict early DM: pretreatment FDG-PET standardized uptake value (SUV), MRI-derived AJCC tumor staging, tumor volume, and dynamic contrast-enhanced (DCE) values. The DCE-derived ve was defined as the volume fraction of the extravascular, extracellular space.Compared with patients without early DM, patients with early DM had higher SUV, tumor volume, DCE mean (median) ve, ve skewness, ve kurtosis, and the largest mean ve selected among sequential slices (P < 0.05). No differences were identified when early DM were defined only according to the results of pretreatment FDG-PET. Among different quantitative DCE parameters, the mean ve had the highest area under curve (AUC, 0.765). However, the AUCs of SUV, tumor volume, mean ve, ve skewness, ve kurtosis, or the largest mean ve selected among the sequential slices did not differ significantly from one another (P = 0.82).Taken together, our results suggest that DCE-derived ve may be a useful parameter in combination with SUV and tumor volume for predicting early DM. Dynamic contrast-enhanced MRI may be complementary to FDG-PET for selecting the most appropriate treatment approach in NPC patients. PMID:26871776

  3. SPIO-conjugated, doxorubicin-loaded microbubbles for concurrent MRI and focused-ultrasound enhanced brain-tumor drug delivery.

    PubMed

    Fan, Ching-Hsiang; Ting, Chien-Yu; Lin, Han-Jung; Wang, Chung-Hsin; Liu, Hao-Li; Yen, Tzu-Chen; Yeh, Chih-Kuang

    2013-05-01

    The blood-brain barrier (BBB) can be temporarily and locally opened by focused ultrasound (FUS) in the presence of circulating microbubbles (MBs). Currently, contrast-enhanced magnetic resonance imaging (CE-MRI) is used to monitor contrast agent leakage to verify BBB-opening and infer drug deposition. However, despite being administered concurrently, MBs, therapeutic agent, and contrast agent have distinct pharmacodynamic behaviors, thus complicating the quantification and optimization of BBB-opening and drug delivery. Here we propose multifunctional MBs loaded with therapeutic agent (doxorubicin; DOX) and conjugated with superparamagnetic iron oxide (SPIO) nanoparticles. These DOX-SPIO-MBs were designed to concurrently open the BBB and perform drug delivery upon FUS exposure, act as dual MRI and ultrasound contrast agent, and allow magnetic targeting (MT) to achieve enhanced drug delivery. We performed burst-tone FUS after injection of DOX-SPIO-MBs, followed by MT with an external magnet attached to the scalp in a rat glioma model. Animals were monitored by T2-weighted MRI and susceptibility weighted imaging and the concentration of SPIO particles was determined by spin-spin relaxivity. We found that DOX-SPIO-MBs were stable and provided significant superparamagnetic/acoustic properties for imaging. BBB-opening and drug delivery were achieved concurrently during the FUS exposure. In addition, MT increased local SPIO deposition in tumor regions by 22.4%. Our findings suggest that DOX-SPIO-MBs with FUS could be an excellent theranostic tool for future image-guided drug delivery to brain tumors. PMID:23433776

  4. Gradient-enhanced volume rendering: an image processing strategy to facilitate whole small bowel imaging with MRI.

    PubMed

    Wyss, Michael; Froehlich, Johannes M; Patak, Michael A; Juli, Christoph F; Scheidegger, Markus B; Zollikofer, Christoph L; Wentz, Klaus U

    2007-04-01

    MRI of the small bowel with positive contrast from orally administered contrast agent is a promising non-invasive imaging method. The aim of our study was to introduce small bowel MRI in a display format that clinicians are accustomed to and that maximizes the amount of information visualized on a single image. Twelve healthy volunteers, median age 32 years (range 18-49 years) participated in the study. A mixture of 20 ml Gd-DOTA (Dotarem), 0.8 g/kg body weight psyllium fibre (Metamucil) and 1.2 l water were sequentially administered over a period of 4 h. Imaging was performed on a 1.5 T unit (Philips Gyroscan, Intera). Fat-saturated, 3D, gradient echo imaging was performed while the patient was in apnea (30 s). Bowel motion was reduced with 40 mg intravenously administered scopolamine (Buscopan). A 3D, gradient-enhanced, volume rendering technique was applied to the 3D data sets. Standard projections [left anterior oblique (LAO), right anterior oblique (RAO), supine and prone] resembling conventional enteroclysis were successfully generated within fewer than 10 min processing time. Reconstructions were reproducible and provided an entire overview of the small bowel. In addition thin-slab volume rendering allowed an overlap-free display of individual structures. Positive contrast from orally administered contrast agent, combined with a gradient enhanced volume rendering method, allows the reconstruction of the small bowel in a pattern resembling conventional double-contrast enteroclysis. Segmental display without overlay is possible. PMID:17021699

  5. A New Approach Using Manganese-Enhanced MRI to Diagnose Acute Mesenteric Ischemia in a Rabbit Model: Initial Experience

    PubMed Central

    Cheng, Cheng; Kuang, Lian-qin; Zhang, Yu-long; Cheng, Hai-yun; Min, Jia-yan; Wang, Yi

    2015-01-01

    Purpose. Manganese-enhanced MRI (MEMRI) has been applied to a wide range of biological and disease research. The purpose of the study was to use MEMRI to diagnose the acute mesenteric ischemia (AMI). Methods. The institutional experimental animal ethics committee approved this study. To optimize the dose of Mn2+ infusion, a dose-dependent curve was obtained using Mn2+-enhanced T1 map MRI by an intravenous infusion 2.5–20 nmol/g body weight (BW) of 50 nmol/L MnCl2. The eighteen animals were divided into control, sham-operated, and AMI groups. AMI models were performed by ligating the superior mesenteric artery (SMA). T1 values were measured on T1 maps in regions of the small intestinal wall and relaxation rate (ΔR1) was calculated. Results. A nonlinear relationship between infused MnCl2 solution dose and increase in small intestinal wall ΔR1 was observed. Control animal exhibited significant Mn2+ clearance over time at the dose of 15 nmol/g BW. In the AMI model, ΔR1 values (0.95 ± 0.13) in the small intestinal wall were significantly lower than in control group (2.05 ± 0.19) after Mn2+ infusion (P < 0.01). Conclusion. The data suggest that MEMRI shows potential as a diagnostic technique that is directly sensitive to the poor or absent perfusion in AMI. PMID:26693487

  6. Added value of hepatobiliary phase gadoxetic acid-enhanced MRI for diagnosing hepatocellular carcinoma in high-risk patients

    PubMed Central

    Phongkitkarun, Sith; Limsamutpetch, Kuruwin; Tannaphai, Penampai; Jatchavala, Janjira

    2013-01-01

    AIM: To determine the added value of hepatobiliary phase (HBP) gadoxetic acid-enhanced magnetic resonance imaging (MRI) in evaluating hepatic nodules in high-risk patients. METHODS: The institutional review board approved this retrospective study and waived the requirement for informed consent. This study included 100 patients at high risk for hepatocellular carcinoma (HCC) and 105 hepatic nodules that were larger than 1 cm. A blind review of two MR image sets was performed in a random order: set 1, unenhanced (T1- and T2-weighted) and dynamic images; and set 2, unenhanced, dynamic 20-min and HBP images. The diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were compared for the two image sets. Univariate and multivariate analyses were performed on the MR characteristics utilized to diagnose HCC. RESULTS: A total of 105 hepatic nodules were identified in 100 patients. Fifty-nine nodules were confirmed to be HCC. The diameter of the 59 HCCs ranged from 1 to 12 cm (mean: 1.9 cm). The remaining 46 nodules were benign (28 were of hepatocyte origin, nine were hepatic cysts, seven were hemangiomas, one was chronic inflammation, and one was focal fat infiltration). The diagnostic accuracy significantly increased with the addition of HBP images, from 88.7% in set 1 to 95.5% in set 2 (P = 0.002). In set 1 vs set 2, the sensitivity and NPV increased from 79.7% to 93.2% and from 78.9% to 91.8%, respectively, whereas the specificity and PPV were not significantly different. The hypointensity on the HBP images was the most sensitive (93.2%), and typical arterial enhancement followed by washout was the most specific (97.8%). The multivariate analysis revealed that typical arterial enhancement followed by washout, hyperintensity on T2-weighted images, and hypointensity on HBP images were statistically significant MRI findings that could diagnose HCC (P < 0.05). CONCLUSION: The addition of HBP gadoxetic acid-enhanced MRI statistically improved the diagnostic accuracy in HCCs larger than 1 cm. Typical arterial enhancement followed by washout and hypointensity on HBP images are useful for diagnosing HCC. PMID:24363528

  7. Incremental Value of Diffusion Weighted and Dynamic Contrast Enhanced MRI in the Detection of Locally Recurrent Prostate Cancer after Radiation Treatment: Preliminary Results

    PubMed Central

    Akin, Oguz; Gultekin, David; Vargas, Hebert Alberto; Zheng, Junting; Moskowitz, Chaya; Pei, Xin; Sperling, Dahlia; Schwartz, Lawrence; Hricak, Hedvig; Zelefsky, Michael

    2013-01-01

    Objectives To assess the incremental value of diffusion-weighted and dynamic contrast-enhanced MRI to T2-weighted MRI in detecting locally recurrent prostate cancer after radiotherapy. Methods Twenty-four patients (median age, 70 years) with a history of radiotherapy-treated prostate cancer underwent multi-parametric MRI (MP-MRI) and transrectal prostate biopsy. Two readers independently scored the likelihood of cancer on a 1-5 scale, using T2WI alone and then adding DWI and DCE-MRI. Areas under receiver operating characteristic curves (AUCs) were estimated at the patient and prostate-side levels. The ADC from DW-MRI and the Ktrans, kep, ve, AUGC90 and AUGC180 from DCE-MRI were recorded. Results Biopsy was positive in 16/24 (67%) and negative in 8/24 (33%) patients. AUCs for readers 1 and 2 increased from 0.64 and 0.53 to 0.95 and 0.86 with MP-MRI, at the patient level, and from 0.73 and 0.66 to 0.90 and 0.79 with MP-MRI, at the prostate-side level (p values <0.05). Biopsy-positive and biopsy-negative prostate sides differed significantly in median ADC [1.44 vs. 1.68 ( 10-3 mm2/s)], median Ktrans [1.07 vs. 0.34 (1/min)], and kep [2.06 vs 1.0 ( 1/min)] (p values <0.05). Conclusions MP-MRI was significantly more accurate than T2WI alone in detecting locally recurrent prostate cancer after radiotherapy PMID:21533634

  8. Sol and Gel States in Peptide Hydrogels Visualized by Gd(III)-enhanced MRI

    PubMed Central

    Weerasekare, Mahika; Taraban, Marc B.; Shi, Xianfeng; Jeong, Eun-Kee; Trewhella, Jill; Yu, Yihua Bruce

    2013-01-01

    The hydrogels assembled from a pair of self-repulsive but mutually-attractive decapeptides are visualized by magnetic resonance imaging. It is found that in the absence of Gd(III)-chelate, gelation has little effect on MRI signal intensity. In the presence of Gd(III)-chelate, gelation leads to significant changes in water relaxation and MR signal intensity. The sol to gel transition is best visualized by T2-weighted imaging using large echo time with the sol producing a bright spot and the gel producing a dark spot. MRI studies indicate high local Gd(III)-chelate concentration. Small-angle X-ray scattering study indicates that this local enrichment of Gd(III)-chelate has two contributing processes: first, the aggregation of peptides into fibers; second, within peptide fibers, Gd(III)-chelate further aggregate into clusters. This work demonstrates that the status of peptide-based hydrogels can be visualized by MRI with the aid of covalently linked Gd(III)-chelates. This result has implications for monitoring peptide scaffolds in vivo. PMID:22252424

  9. Head MRI

    MedlinePLUS

    ... the head; MRI - cranial; NMR - cranial; Cranial MRI; Brain MRI; MRI - brain; MRI - head ... tell your health care provider if you have: Brain aneurysm clips Certain types of artificial heart valves ...

  10. In-Vivo Imaging of Cell Migration Using Contrast Enhanced MRI and SVM Based Post-Processing

    PubMed Central

    Budinsky, Lubos; Fabry, Ben

    2015-01-01

    The migration of cells within a living organism can be observed with magnetic resonance imaging (MRI) in combination with iron oxide nanoparticles as an intracellular contrast agent. This method, however, suffers from low sensitivity and specificty. Here, we developed a quantitative non-invasive in-vivo cell localization method using contrast enhanced multiparametric MRI and support vector machines (SVM) based post-processing. Imaging phantoms consisting of agarose with compartments containing different concentrations of cancer cells labeled with iron oxide nanoparticles were used to train and evaluate the SVM for cell localization. From the magnitude and phase data acquired with a series of T2*-weighted gradient-echo scans at different echo-times, we extracted features that are characteristic for the presence of superparamagnetic nanoparticles, in particular hyper- and hypointensities, relaxation rates, short-range phase perturbations, and perturbation dynamics. High detection quality was achieved by SVM analysis of the multiparametric feature-space. The in-vivo applicability was validated in animal studies. The SVM detected the presence of iron oxide nanoparticles in the imaging phantoms with high specificity and sensitivity with a detection limit of 30 labeled cells per mm3, corresponding to 19 μM of iron oxide. As proof-of-concept, we applied the method to follow the migration of labeled cancer cells injected in rats. The combination of iron oxide labeled cells, multiparametric MRI and a SVM based post processing provides high spatial resolution, specificity, and sensitivity, and is therefore suitable for non-invasive in-vivo cell detection and cell migration studies over prolonged time periods. PMID:26656497

  11. The use of error-category mapping in pharmacokinetic model analysis of dynamic contrast-enhanced MRI data

    PubMed Central

    Gill, Andrew B.; Anandappa, Gayathri; Patterson, Andrew J.; Priest, Andrew N.; Graves, Martin J.; Janowitz, Tobias; Jodrell, Duncan I.; Eisen, Tim; Lomas, David J.

    2015-01-01

    This study introduces the use of error-category mapping in the interpretation of pharmacokinetic (PK) model parameter results derived from dynamic contrast-enhanced (DCE-) MRI data. Eleven patients with metastatic renal cell carcinoma were enrolled in a multiparametric study of the treatment effects of bevacizumab. For the purposes of the present analysis, DCE-MRI data from two identical pre-treatment examinations were analysed by application of the extended Tofts model (eTM), using in turn a model arterial input function (AIF), an individually-measured AIF and a sample-average AIF. PK model parameter maps were calculated. Errors in the signal-to-gadolinium concentration ([Gd]) conversion process and the model-fitting process itself were assigned to category codes on a voxel-by-voxel basis, thereby forming a colour-coded error-category map for each imaged slice. These maps were found to be repeatable between patient visits and showed that the eTM converged adequately in the majority of voxels in all the tumours studied. However, the maps also clearly indicated sub-regions of low Gd uptake and of non-convergence of the model in nearly all tumours. The non-physical condition ve ?1 was the most frequently indicated error category and appeared sensitive to the form of AIF used. This simple method for visualisation of errors in DCE-MRI could be used as a routine quality-control technique and also has the potential to reveal otherwise hidden patterns of failure in PK model applications. PMID:25460333

  12. Brain Processing of Biologically Relevant Odors in the Awake Rat, as Revealed by Manganese-Enhanced MRI

    PubMed Central

    Lehallier, Benoist; Rampin, Olivier; Saint-Albin, Audrey; Jrme, Nathalie; Ouali, Christian; Maurin, Yves; Bonny, Jean-Marie

    2012-01-01

    Background So far, an overall view of olfactory structures activated by natural biologically relevant odors in the awake rat is not available. Manganese-enhanced MRI (MEMRI) is appropriate for this purpose. While MEMRI has been used for anatomical labeling of olfactory pathways, functional imaging analyses have not yet been performed beyond the olfactory bulb. Here, we have used MEMRI for functional imaging of rat central olfactory structures and for comparing activation maps obtained with odors conveying different biological messages. Methodology/Principal Findings Odors of male fox feces and of chocolate flavored cereals were used to stimulate conscious rats previously treated by intranasal instillation of manganese (Mn). MEMRI activation maps showed Mn enhancement all along the primary olfactory cortex. Mn enhancement elicited by male fox feces odor and to a lesser extent that elicited by chocolate odor, differed from that elicited by deodorized air. This result was partly confirmed by c-Fos immunohistochemistry in the piriform cortex. Conclusion/Significance By providing an overall image of brain structures activated in awake rats by odorous stimulation, and by showing that Mn enhancement is differently sensitive to different stimulating odors, the present results demonstrate the interest of MEMRI for functional studies of olfaction in the primary olfactory cortex of laboratory small animals, under conditions close to natural perception. Finally, the factors that may cause the variability of the MEMRI signal in response to different odor are discussed. PMID:23119035

  13. Layer-Specific Manganese-Enhanced MRI of the Diabetic Rat Retina in Light and Dark Adaptation at 11.7 Tesla

    PubMed Central

    Muir, Eric R.; Chandra, Saurav B.; De La Garza, Bryan H.; Velagapudi, Chakradhar; Abboud, Hanna E.; Duong, Timothy Q.

    2015-01-01

    Purpose. To employ high-resolution manganese-enhanced MRI (MEMRI) to study abnormal calcium activity in different cell layers in streptozotocin-induced diabetic rat retinas, and to determine whether MEMRI detects changes at earlier time points than previously reported. Methods. Sprague-Dawley rats were studied 14 days (n = 8) and 30 days (n = 5) after streptozotocin (STZ) or vehicle (n = 7) injection. Manganese-enhanced MRI at 20 × 20 × 700 μm, in which contrast is based on manganese as a calcium analogue and an MRI contrast agent, was obtained in light and dark adaptation of the retina in the same animals in which one eye was covered and the fellow eye was not. The MEMRI activity encoding of the light and dark adaptation was achieved in awake conditions and imaged under anesthesia. Results. Manganese-enhanced MRI showed three layers, corresponding to the inner retina, outer retina, and the choroid. In normal animals, the outer retina showed higher MEMRI activity in dark compared to light; the inner retina displayed lower activity in dark compared to light; and the choroid showed no difference in activity. Manganese-enhanced MRI activity changed as early as 14 days after hyperglycemia and decreased with duration of hyperglycemia in the outer retina in dark relative to light adaptation. The choroid also had altered MEMRI activity at 14 days, which returned to normal by 30 days. No differences in MEMRI activity were detected in the inner retina. Conclusions. Manganese-enhanced MRI detects progressive reduction in calcium activity with duration of hyperglycemia in the outer retina as early as 14 days after hyperglycemia, earlier than any other time point reported in the literature. PMID:26098468

  14. Automated scoring of regional lung perfusion in children from contrast enhanced 3D MRI

    NASA Astrophysics Data System (ADS)

    Heimann, Tobias; Eichinger, Monika; Bauman, Grzegorz; Bischoff, Arved; Puderbach, Michael; Meinzer, Hans-Peter

    2012-03-01

    MRI perfusion images give information about regional lung function and can be used to detect pulmonary pathologies in cystic fibrosis (CF) children. However, manual assessment of the percentage of pathologic tissue in defined lung subvolumes features large inter- and intra-observer variation, making it difficult to determine disease progression consistently. We present an automated method to calculate a regional score for this purpose. First, lungs are located based on thresholding and morphological operations. Second, statistical shape models of left and right children's lungs are initialized at the determined locations and used to precisely segment morphological images. Segmentation results are transferred to perfusion maps and employed as masks to calculate perfusion statistics. An automated threshold to determine pathologic tissue is calculated and used to determine accurate regional scores. We evaluated the method on 10 MRI images and achieved an average surface distance of less than 1.5 mm compared to manual reference segmentations. Pathologic tissue was detected correctly in 9 cases. The approach seems suitable for detecting early signs of CF and monitoring response to therapy.

  15. Functional Lung MRI in Chronic Obstructive Pulmonary Disease: Comparison of T1 Mapping, Oxygen-Enhanced T1 Mapping and Dynamic Contrast Enhanced Perfusion

    PubMed Central

    Jobst, Bertram J.; Triphan, Simon M. F.; Sedlaczek, Oliver; Anjorin, Angela; Kauczor, Hans Ulrich; Biederer, Jrgen; Ley-Zaporozhan, Julia; Ley, Sebastian; Wielptz, Mark O.

    2015-01-01

    Purpose Monitoring of regional lung function in interventional COPD trials requires alternative endpoints beyond global parameters such as FEV1. T1 relaxation times of the lung might allow to draw conclusions on tissue composition, blood volume and oxygen fraction. The aim of this study was to evaluate the potential value of lung Magnetic resonance imaging (MRI) with native and oxygen-enhanced T1 mapping for the assessment of COPD patients in comparison with contrast enhanced perfusion MRI. Materials and Methods 20 COPD patients (GOLD I-IV) underwent a coronal 2-dimensional inversion recovery snapshot flash sequence (8 slices/lung) at room air and during inhalation of pure oxygen, as well as dynamic contrast-enhanced first-pass perfusion imaging. Regional distribution of T1 at room air (T1), oxygen-induced T1 shortening (?T1) and peak enhancement were rated by 2 chest radiologists in consensus using a semi-quantitative 3-point scale in a zone-based approach. Results Abnormal T1 and ?T1 were highly prevalent in the patient cohort. T1 and ?T1 correlated positively with perfusion abnormalities (r = 0.81 and r = 0.80; p&0.001), and with each other (r = 0.80; p<0.001). In GOLD stages I and II ?T1 was normal in 16/29 lung zones with mildly abnormal perfusion (15/16 with abnormal T1). The extent of T1 (r = 0.45; p<0.05), ?T1 (r = 0.52; p<0.05) and perfusion abnormalities (r = 0.52; p<0.05) showed a moderate correlation with GOLD stage. Conclusion Native and oxygen-enhanced T1 mapping correlated with lung perfusion deficits and severity of COPD. Under the assumption that T1 at room air correlates with the regional pulmonary blood pool and that oxygen-enhanced T1 reflects lung ventilation, both techniques in combination are principally suitable to characterize ventilation-perfusion imbalance. This appears valuable for the assessment of regional lung characteristics in COPD trials without administration of i.v. contrast. PMID:25822195

  16. Enhancing the quantification of tissue sodium content by MRI: time-efficient sodium B1 mapping at clinical field strengths.

    PubMed

    Lommen, Jonathan; Konstandin, Simon; Krämer, Philipp; Schad, Lothar R

    2016-02-01

    Tissue sodium content (TSC) is a sensitive measure of pathological changes and can be detected non-invasively by MRI. For the absolute quantification of TSC, B1 inhomogeneities must be corrected, which is not well established beyond research applications. An in-depth analysis of B1 mapping methods which are suitable for application in TSC quantification is presented. On the basis of these results, a method for simultaneous B1 mapping and imaging is proposed in order to enhance accuracy and to reduce measurement time at clinical field strengths. The B1 mapping techniques used were phase-sensitive (PS), Bloch-Siegert shift (BSS), double-angle (DAM) and actual flip-angle imaging (AFI) methods. Experimental and theoretical comparisons demonstrated that the PS technique yields the most accurate field profiles and exhibits the highest signal-to-noise ratio (SNR). Simultaneous B1 mapping and imaging was performed for the PS method, employing both degrees of freedom of the MR signal: the B1 field is encoded into signal phase and the amplitude provides the concentration information. In comparison with the more established DAM, a 13% higher SNR was obtained and field effects could be corrected more accurately without the need for additional measurement time. The protocol developed was applied to measure TSC in the healthy human head at an isotropic resolution of 4 mm. TSC was determined to be 35 ± 1 mM in white matter and 134 ± 3 mM in vitreous humor. By employing the proposed simultaneous characterization of the B1 field and acquisition of the spin density-weighted sodium signal, the accuracy of the non-invasive measurement of TSC is enhanced and the measurement time is reduced. This should allow (23) Na MRI to be better incorporated into clinical studies and routine. Copyright © 2015 John Wiley & Sons, Ltd. PMID:25904161

  17. Rationally Separating the Corona and Membrane Functions of Polymer Vesicles for Enhanced T₂ MRI and Drug Delivery.

    PubMed

    Qin, Jingya; Liu, Qiuming; Zhang, Junxue; Chen, Jing; Chen, Shuai; Zhao, Yao; Du, Jianzhong

    2015-07-01

    It is an important challenge to in situ grow ultrafine super-paramagnetic iron oxide nanoparticles (SPIONs) in drug carriers such as polymer vesicles (also called polymersomes) while keeping their biodegradability for enhanced T2-weighted magnetic resonance imaging (MRI) and drug delivery. Herein, we present a new strategy by rationally separating the corona and membrane functions of polymer vesicles to solve the above problem. We designed a poly(ethylene oxide)-block-poly(ε-caprolactone)-block-poly(acrylic acid) (PEO43-b-PCL98-b-PAA25) triblock copolymer and self-assembled it into polymer vesicle. The PAA chains in the vesicle coronas are responsible for the in situ nanoprecipitation of ultrafine SPIONs, while the vesicle membrane composed of PCL is biodegradable. The SPIONs-decorated vesicle is water-dispersible, biocompatible, and slightly cytotoxic to normal human cells. Dynamic light scattering, transmission electron microscopy, energy disperse spectroscopy, and vibrating sample magnetometer revealed the formation of ultrafine super-paramagnetic Fe3O4 nanoparticles (1.9 ± 0.3 nm) in the coronas of polymer vesicles. Furthermore, the CCK-8 assay revealed low cytotoxicity of vesicles against normal L02 liver cells without and with Fe3O4 nanoparticles. The in vitro and in vivo MRI experiments confirmed the enhanced T2-weighted MRI sensitivity and excellent metastasis in mice. The loading and release experiments of an anticancer drug, doxorubicin hydrochloride (DOX·HCl), indicated that the Fe3O4-decorated magnetic vesicles have potential applications as a nanocarrier for anticancer drug delivery. Moreover, the polymer vesicle is degradable in the presence of enzyme such as Pseudomonas lipases, and the ultrafine Fe3O4 nanoparticles in the vesicle coronas are confirmed to be degradable under weakly acidic conditions. Overall, this decoration-in-vesicle-coronas strategy provides us with a new insight for preparing water-dispersible ultrafine super-paramagnetic Fe3O4 nanoparticles with promising theranostic applications in biomedicine. PMID:26046951

  18. Gd-EOB-DTPA-enhanced 3.0-Tesla MRI findings for the preoperative detection of focal liver lesions: Comparison with iodine-enhanced multi-detector computed tomography

    NASA Astrophysics Data System (ADS)

    Park, Hyong-Hu; Goo, Eun-Hoe; Im, In-Chul; Lee, Jae-Seung; Kim, Moon-Jib; Kwak, Byung-Joon; Chung, Woon-Kwan; Dong, Kyung-Rae

    2012-12-01

    The safety of gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic-acid (Gd-EOB-DTPA) has been confirmed, but more study is needed to assess the diagnostic accuracy of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) in patients with a hepatocellular carcinoma (HCC) for whom surgical treatment is considered or with a metastatic hepatoma. Research is also needed to examine the rate of detection of hepatic lesions compared to multi-detector computed tomography (MDCT), which is used most frequently to localize and characterize a HCC. Gd-EOB-DTPA-enhanced MRI and iodine-enhanced MDCT imaging were compared for the preoperative detection of focal liver lesions. The clinical usefulness of each method was examined. The current study enrolled 79 patients with focal liver lesions who preoperatively underwent MRI and MDCT. In these patients, there was less than one month between the two diagnostic modalities. Imaging data were taken before and after contrast enhancement in both methods. To evaluate the images, we analyzed the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) in the lesions and the liver parenchyma. To compare the sensitivity of the two methods, we performed a quantitative analysis of the percentage signal intensity of the liver (PSIL) on a high resolution picture archiving and communication system (PACS) monitor (paired-samples t-test, p < 0.05). The enhancement was evaluated based on a consensus of four observers. The enhancement pattern and the morphological features during the arterial and the delayed phases were correlated between the Gd-EOB-DTPA-enhanced MRI findings and the iodine-enhanced MDCT by using an adjusted x2 test. The SNRs, CNRs, and PSIL all had a greater detection rate in Gd-EOB-DTPA enhanced MRI than in iodine-enhanced MDCT. Hepatocyte-selective uptake was observed 20 minutes after the injection in the focal nodular hyperplasia (FNH, 9/9), adenoma (9/10), and highly-differentiated HCC (grade G1, 27/30). Rim enhancement was detected in all metastases (30/30). During the arterial and the delayed phases, good overall agreement between the gadoxetic-acid-enhanced MR and CT was observed (x2 test, p < 0.05). For the preoperative detection of focal liver lesions, Gd-EOB-DTPA-enhanced MRI had a higher diagnostic value and higher detection rate than iodine-enhanced MDCT. The arterial and the delayed dynamic enhancement patterns, and the gadoxetic-acid-enhanced MR imaging can provide information on the possible degree of cellular differentiation of a HCC, adenoma or metastatic tumor.

  19. Hydrothermally synthesized PEGylated calcium phosphate nanoparticles incorporating Gd-DTPA for contrast enhanced MRI diagnosis of solid tumors.

    PubMed

    Mi, Peng; Kokuryo, Daisuke; Cabral, Horacio; Kumagai, Michiaki; Nomoto, Takahiro; Aoki, Ichio; Terada, Yasuko; Kishimura, Akihiro; Nishiyama, Nobuhiro; Kataoka, Kazunori

    2014-01-28

    Organic-inorganic hybrid nanoparticles with calcium phosphate (CaP) core and PEGylated shell were developed to incorporate magnetic resonance imaging (MRI) contrast agent diethylenetriaminepentaacetic acid gadolinium (III) (Gd-DTPA) for noninvasive diagnosis of solid tumors. A two-step preparation method was applied to elaborate hybrid nanoparticles with a z-average hydrodynamic diameter about 80nm, neutral surface ?-potential and high colloidal stability in physiological environments by self-assembly of poly(ethylene glycol)-b-poly(aspartic acid) block copolymer, Gd-DTPA, and CaP in aqueous solution, followed with hydrothermal treatment. Incorporation into the hybrid nanoparticles allowed Gd-DTPA to show significant enhanced retention ratio in blood circulation, leading to high accumulation in tumor positions due to enhanced permeability and retention (EPR) effect. Moreover, Gd-DTPA revealed above 6 times increase of relaxivity in the nanoparticle system compared to free form, and eventually, selective and elevated contrast enhancements in the tumor positions were observed. These results indicate the high potential of Gd-DTPA-loaded PEGylated CaP nanoparticles as a novel contrast agent for noninvasive cancer diagnosis. PMID:24211705

  20. Hepatocellular Adenoma: Evaluation with Contrast-Enhanced Ultrasound and MRI and Correlation with Pathologic and Phenotypic Classification in 26 Lesions

    PubMed Central

    Manichon, Anne-Frdrique; Bancel, Brigitte; Durieux-Millon, Marion; Ducerf, Christian; Mabrut, Jean-Yves; Lepogam, Marie-Annick; Rode, Agns

    2012-01-01

    Purpose. To review the contrast-enhanced ultrasonographic (CEUS) and magnetic resonance (MR) imaging findings in 25 patients with 26 hepatocellular adenomas (HCAs) and to compare imaging features with histopathologic results from resected specimen considering the new immunophenotypical classification. Material and Methods. Two abdominal radiologists reviewed retrospectively CEUS cineloops and MR images in 26 HCA. All pathological specimens were reviewed and classified into four subgroups (steatotic or HNF 1? mutated, inflammatory, atypical or ?-catenin mutated, and unspecified). Inflammatory infiltrates were scored, steatosis, and telangiectasia semiquantitatively evaluated. Results. CEUS and MRI features are well correlated: among the 16 inflammatory HCA, 7/16 presented typical imaging features: hypersignal T2, strong arterial enhancement with a centripetal filling, persistent on delayed phase. 6 HCA were classified as steatotic with typical imaging features: a drop out signal, slight arterial enhancement, vanishing on late phase. Four HCA were classified as atypical with an HCC developed in one. Five lesions displayed important steatosis (>50%) without belonging to the HNF1? group. Conclusion. In half cases, inflammatory HCA have specific imaging features well correlated with the amount of telangiectasia and inflammatory infiltrates. An HCA with important amount of steatosis noticed on chemical shift images does not always belong to the HNF1? group. PMID:22811588

  1. Quantification techniques to minimize the effects of native T1 variation and B1 inhomogeneity in dynamic contrast-enhanced MRI of the breast at 3 T.

    PubMed

    Azlan, Che A; Ahearn, Trevor S; Di Giovanni, Pierluigi; Semple, Scott I K; Gilbert, Fiona J; Redpath, Thomas W

    2012-02-01

    The variation of the native T(1) (T(10)) of different tissues and B(1) transmission-field inhomogeneity at 3 T are major contributors of errors in the quantification of breast dynamic contrast-enhanced MRI. To address these issues, we have introduced new enhancement indices derived from saturation-recovery snapshot-FLASH (SRSF) images. The stability of the new indices, i.e., the SRSF enhancement factor (EF(SRSF)) and its simplified version (EF'(SRSF)) with respect to differences in T(10) and B(1) inhomogeneity was compared against a typical index used in breast dynamic contrast-enhanced MRI, i.e., the enhancement ratio (ER), by using computer simulations. Imaging experiments with Gd-DTPA-doped gel phantoms and a female volunteer were also performed. A lower error was observed in the new indices compared to enhancement ratio in the presence of typical T(10) variation and B(1) inhomogeneity. At changes of relaxation rate (?R(1)) of 8 s(-1), the differences between a T(10) of 1266 and 566 ms are <1, 12, and 58%, respectively, for EF(SRSF), EF'(SRSF), and ER, whereas differences of 20, 8, and 51%, respectively, result from a 50% B(1) field reduction at the same ?R(1). These quantification techniques may be a solution to minimize the effect of T(10) variation and B(1) inhomogeneity on dynamic contrast-enhanced MRI of the breast at 3 T. PMID:21656561

  2. Multimodality Functional Imaging in Radiation Therapy Planning: Relationships between Dynamic Contrast-Enhanced MRI, Diffusion-Weighted MRI, and 18F-FDG PET

    PubMed Central

    Mera Iglesias, Moiss; Aramburu Nez, David; del Olmo Claudio, Jos Luis; Salvador Gmez, Francisco; Driscoll, Brandon; Coolens, Catherine; Alba Castro, Jos L.; Muoz, Victor

    2015-01-01

    Objectives. Biologically guided radiotherapy needs an understanding of how different functional imaging techniques interact and link together. We analyse three functional imaging techniques that can be useful tools for achieving this objective. Materials and Methods. The three different imaging modalities from one selected patient are ADC maps, DCE-MRI, and 18F-FDG PET/CT, because they are widely used and give a great amount of complementary information. We show the relationship between these three datasets and evaluate them as markers for tumour response or hypoxia marker. Thus, vascularization measured using DCE-MRI parameters can determine tumour hypoxia, and ADC maps can be used for evaluating tumour response. Results. ADC and DCE-MRI include information from 18F-FDG, as glucose metabolism is associated with hypoxia and tumour cell density, although 18F-FDG includes more information about the malignancy of the tumour. The main disadvantage of ADC maps is the distortion, and we used only low distorted regions, and extracellular volume calculated from DCE-MRI can be considered equivalent to ADC in well-vascularized areas. Conclusion. A dataset for achieving the biologically guided radiotherapy must include a tumour density study and a hypoxia marker. This information can be achieved using only MRI data or only PET/CT studies or mixing both datasets. PMID:25788972

  3. Monitoring Pc 4-mediated photodynamic therapy of U87 tumors with dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) in the athymic nude rat

    NASA Astrophysics Data System (ADS)

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

    2008-02-01

    Post-operative verification of the specificity and sensitivity of photodynamic therapy (PDT) is most pressing for deeply placed lesions such as brain tumors. We wish to determine whether Dynamic Contrast Enhanced-Magnetic Resonance Imaging (DCE-MRI) can provide a non-invasive and unambiguous quantitative measure of the specificity and sensitivity of brain tumor PDT. Methods: 2.5 x 10 5 U87 cells were injected into the brains of six athymic nude rats. After 5-6 days, the animals received 0.5 mg/kg b.w. of the phthalocyanine photosensitizer Pc 4 via tail-vein injection. On day 7 peri-tumor DCE-MRI images were acquired on a 7T microMRI scanner before and after tail-vein administration of 100 ?L gadolinium and 400 ?L saline. After this scan the animals received a 30 J/cm2 dose of 672-nm light from a diode laser (i.e., PDT). The DCE-MRI scan protocol was repeated on day 13. Next, the animals were euthanized and their brains were explanted for Hematoxylin and Eosin (H&E) histology. Results: No tumor was found in one animal. The DCE-MRI images of the other five animals demonstrated significant tumor enhancement increase (p < 0.053 two-sided t-test and p < 0.026 one-sided t-test) following PDT. H&E histology presented moderate to severe tumor necrosis. Discussion: The change in signal detected by DCE-MRI appears to be due to PDT-induced tumor necrosis. This DCE-MRI signal appears to provide a quantitative, non-invasive measure of the outcome of PDT in this animal model and may be useful for determining the safety and effectiveness of PDT in deeply placed tumors (e.g., glioma).

  4. Pulmonary Embolism Originating from a Hepatic Hydatid Cyst Ruptured into the Inferior Vena Cava: CT and MRI Findings

    PubMed Central

    Poyraz, Necdet; Demirbaş, Soner; Korkmaz, Celalettin; Uzun, Kürşat

    2016-01-01

    Pulmonary embolism due to hydatid cysts is a very rare clinical entity. Hydatid pulmonary embolism can be distinguished from other causes of pulmonary embolism with contrast-enhanced computed tomography (CECT) and magnetic resonance imaging (MRI). MRI especially displays the cystic nature of lesions better than CECT. Here we report a 45-year-old male patient with the pulmonary embolism due to ruptured hydatid liver cyst into the inferior vena cava. PMID:26904344

  5. Highly accelerated dynamic contrast-enhanced MRI with temporal constrained reconstruction.

    PubMed

    Huajun She; Rong-Rong Chen; DiBella, Edward V R; Schabel, Matthias; Ying, Leslie

    2014-01-01

    For DCE MRI applications, the images of adjacent time frames are often similar, especially when motion is minimal, in which case temporal TV is a reasonable regularization term. Temporal constraint reconstruction (TCR) has been developed to reconstruct dynamic images from undersampled k-t space data based on such prior information. However, the convergence speed of the algorithm highly depends on the initialization method. In this study, we study initialization using a composite high resolution image based on a jigsaw sampling pattern during pre-contrast frames. The proposed initialization method converges much faster than a conventional initialization method using low resolution images, especially at high reduction factors. In vivo breast imaging experiments were carried out to evaluate the performance of the proposed method. Experiments show the new initialization method allows TCR to achieve a high reduction factor up to 40 without compromising much of the spatial or temporal resolution. The reconstruction errors are much lower than those using the low resolution initialization when the same number of measurements is used. PMID:25570475

  6. In vivo Mn-enhanced MRI for early tumor detection and growth rate analysis in a mouse medulloblastoma model.

    PubMed

    Suero-Abreu, Giselle A; Praveen Raju, G; Aristizbal, Orlando; Volkova, Eugenia; Wojcinski, Alexandre; Houston, Edward J; Pham, Diane; Szulc, Kamila U; Colon, Daniel; Joyner, Alexandra L; Turnbull, Daniel H

    2014-12-01

    Mouse models have increased our understanding of the pathogenesis of medulloblastoma (MB), the most common malignant pediatric brain tumor that often forms in the cerebellum. A major goal of ongoing research is to better understand the early stages of tumorigenesis and to establish the genetic and environmental changes that underlie MB initiation and growth. However, studies of MB progression in mouse models are difficult due to the heterogeneity of tumor onset times and growth patterns and the lack of clinical symptoms at early stages. Magnetic resonance imaging (MRI) is critical for noninvasive, longitudinal, three-dimensional (3D) brain tumor imaging in the clinic but is limited in resolution and sensitivity for imaging early MBs in mice. In this study, high-resolution (100 ?m in 2 hours) and high-throughput (150 ?m in 15 minutes) manganese-enhanced MRI (MEMRI) protocols were optimized for early detection and monitoring of MBs in a Patched-1 (Ptch1) conditional knockout (CKO) model. The high tissue contrast obtained with MEMRI revealed detailed cerebellar morphology and enabled detection of MBs over a wide range of stages including pretumoral lesions as early as 2 to 3 weeks postnatal with volumes close to 0.1 mm(3). Furthermore, longitudinal MEMRI allowed noninvasive monitoring of tumors and demonstrated that lesions within and between individuals have different tumorigenic potentials. 3D volumetric studies allowed quantitative analysis of MB tumor morphology and growth rates in individual Ptch1-CKO mice. These results show that MEMRI provides a powerful method for early in vivo detection and longitudinal imaging of MB progression in the mouse brain. PMID:25499213

  7. Analysis of parametric histogram from dynamic contrast-enhanced MRI: application in evaluating brain tumor response to radiotherapy.

    PubMed

    Peng, Shin-Lei; Chen, Chih-Feng; Liu, Ho-Ling; Lui, Chun-Chung; Huang, Yu-Jie; Lee, Tsung-Han; Chang, Chiung-Chih; Wang, Fu-Nien

    2013-04-01

    Dynamic contrast-enhanced MRI (DCE MRI) has been used to study tumor response to treatment for many years. In this study, the modified full width at half-maximum (mFWHM), calculated from the wash-in slope histogram, is proposed as a parameter for the evaluation of changes in tumor heterogeneity which respond to radiotherapy. Twenty-five patients with brain tumors were evaluated and divided into the nonresponder group (n = 11) and the responder group (n = 14) according to the Response Evaluation Criteria in Solid Tumors (RECIST). All selected tumors were evaluated by mFWHM ratios of post- to pre-therapy (the ratio was defined as the therapeutic mFWHM ratio, TMR). The changes in kurtosis of the histograms and the averaged K(trans) within a tumor were also calculated for comparison. The receiver operating characteristic analysis and Kaplan-Meier curves were used to examine the diagnosis ability. The TMR values were significantly higher in nonresponders than in responders (p < 0.001). When compared with the other two parameters, the proposed method also demonstrated better sensitivity and specificity. When adopting the TMR for the estimation of prognosis after therapy, there was a significant difference between the population survival curves. In conclusion, the derived mFWHM reflects tumor heterogeneity, and the ability to depict patient survival probability from TMR corresponds well with that from RECIST. The results reveal that, in brain tumors, progression may be exhibited not only by tumor size, but also by tumor heterogeneity. PMID:23073840

  8. Quality assurance in MRI breast screening: comparing signal-to-noise ratio in dynamic contrast-enhanced imaging protocols

    NASA Astrophysics Data System (ADS)

    Kousi, Evanthia; Borri, Marco; Dean, Jamie; Panek, Rafal; Scurr, Erica; Leach, Martin O.; Schmidt, Maria A.

    2016-01-01

    MRI has been extensively used in breast cancer staging, management and high risk screening. Detection sensitivity is paramount in breast screening, but variations of signal-to-noise ratio (SNR) as a function of position are often overlooked. We propose and demonstrate practical methods to assess spatial SNR variations in dynamic contrast-enhanced (DCE) breast examinations and apply those methods to different protocols and systems. Four different protocols in three different MRI systems (1.5 and 3.0 T) with receiver coils of different design were employed on oil-filled test objects with and without uniformity filters. Twenty 3D datasets were acquired with each protocol; each dataset was acquired in under 60 s, thus complying with current breast DCE guidelines. In addition to the standard SNR calculated on a pixel-by-pixel basis, we propose other regional indices considering the mean and standard deviation of the signal over a small sub-region centred on each pixel. These regional indices include effects of the spatial variation of coil sensitivity and other structured artefacts. The proposed regional SNR indices demonstrate spatial variations in SNR as well as the presence of artefacts and sensitivity variations, which are otherwise difficult to quantify and might be overlooked in a clinical setting. Spatial variations in SNR depend on protocol choice and hardware characteristics. The use of uniformity filters was shown to lead to a rise of SNR values, altering the noise distribution. Correlation between noise in adjacent pixels was associated with data truncation along the phase encoding direction. Methods to characterise spatial SNR variations using regional information were demonstrated, with implications for quality assurance in breast screening and multi-centre trials.

  9. Quality assurance in MRI breast screening: comparing signal-to-noise ratio in dynamic contrast-enhanced imaging protocols.

    PubMed

    Kousi, Evanthia; Borri, Marco; Dean, Jamie; Panek, Rafal; Scurr, Erica; Leach, Martin O; Schmidt, Maria A

    2016-01-01

    MRI has been extensively used in breast cancer staging, management and high risk screening. Detection sensitivity is paramount in breast screening, but variations of signal-to-noise ratio (SNR) as a function of position are often overlooked. We propose and demonstrate practical methods to assess spatial SNR variations in dynamic contrast-enhanced (DCE) breast examinations and apply those methods to different protocols and systems. Four different protocols in three different MRI systems (1.5 and 3.0 T) with receiver coils of different design were employed on oil-filled test objects with and without uniformity filters. Twenty 3D datasets were acquired with each protocol; each dataset was acquired in under 60?s, thus complying with current breast DCE guidelines. In addition to the standard SNR calculated on a pixel-by-pixel basis, we propose other regional indices considering the mean and standard deviation of the signal over a small sub-region centred on each pixel. These regional indices include effects of the spatial variation of coil sensitivity and other structured artefacts. The proposed regional SNR indices demonstrate spatial variations in SNR as well as the presence of artefacts and sensitivity variations, which are otherwise difficult to quantify and might be overlooked in a clinical setting. Spatial variations in SNR depend on protocol choice and hardware characteristics. The use of uniformity filters was shown to lead to a rise of SNR values, altering the noise distribution. Correlation between noise in adjacent pixels was associated with data truncation along the phase encoding direction. Methods to characterise spatial SNR variations using regional information were demonstrated, with implications for quality assurance in breast screening and multi-centre trials. PMID:26605957

  10. Automatic detection of gadolinium-enhancing multiple sclerosis lesions in brain MRI using conditional random fields.

    PubMed

    Karimaghaloo, Zahra; Shah, Mohak; Francis, Simon J; Arnold, Douglas L; Collins, D Louis; Arbel, Tal

    2012-06-01

    Gadolinium-enhancing lesions in brain magnetic resonance imaging of multiple sclerosis (MS) patients are of great interest since they are markers of disease activity. Identification of gadolinium-enhancing lesions is particularly challenging because the vast majority of enhancing voxels are associated with normal structures, particularly blood vessels. Furthermore, these lesions are typically small and in close proximity to vessels. In this paper, we present an automatic, probabilistic framework for segmentation of gadolinium-enhancing lesions in MS using conditional random fields. Our approach, through the integration of different components, encodes different information such as correspondence between the intensities and tissue labels, patterns in the labels, or patterns in the intensities. The proposed algorithm is evaluated on 80 multimodal clinical datasets acquired from relapsing-remitting MS patients in the context of multicenter clinical trials. The experimental results exhibit a sensitivity of 98% with a low false positive lesion count. The performance of the proposed algorithm is also compared to a logistic regression classifier, a support vector machine and a Markov random field approach. The results demonstrate superior performance of the proposed algorithm at successfully detecting all of the gadolinium-enhancing lesions while maintaining a low false positive lesion count. PMID:22318484

  11. Noninvasive Topical Loading for Manganese-Enhanced MRI of the Mouse Visual System

    PubMed Central

    Campbell, Bruce; Lunderville, Chantal; Won, Eric; Liang, Hsiao-Fang

    2011-01-01

    Purpose. To evaluate topical loading as an alternative to intravitreal injection for Mn2+-enhanced magnetic resonance imaging (MEMRI) of the visual system. Methods. Topical administration of 0.5 to 1.5 M MnCl2 and intravitreal injections with 0.5 ?L 100 mM and 2 ?L 1 M MnCl2 for mouse MEMRI were conducted, followed by immunohistochemistry. In another mouse group, two topical administrations of 1 M Mn2+ were applied to the same animals 7 days apart, to evaluate the use of MEMRI in a time course study. Dynamic imaging was also conducted to reveal how Mn2+ travels to the retina. MEMRI with topically loaded MnCl2 was also conducted in eyes with retinal ischemia, to evaluate whether the enhancements required healthy neurons. Results. After 1 day, topical administration of 1 M and 1.5 M MnCl2 rendered significant signal enhancement (up to 20%) in the superior colliculus (P < 0.05) that was equivalent to that of the 2-?L 1 M injection. Repeated exposure to Mn2+ showed reproduced enhancement. Dynamic imaging showed significant enhancement in the iris, retina, and lens boundary, but not in the vitreous space. In retinal ischemic eyes, no enhancement of MEMRI was detected in the optic nerves. The immunohistochemistry of the optic nerve (1.5 mm anterior to the chiasm) and retina showed no injury 1 week after Mn2+ topical administrations to each mouse. Conclusions. The results demonstrated the feasibility of using topical administration of Mn2+ for MEMRI. Topically loaded Mn2+ did not diffuse into the vitreous space, but was it may have been absorbed into the iris to diffuse or travel via the capillary circulation to reach the retina. PMID:21421878

  12. Enhanced disease characterization through multi network functional normalization in fMRI.

    PubMed

    etin, Mustafa S; Khullar, Siddharth; Damaraju, Eswar; Michael, Andrew M; Baum, Stefi A; Calhoun, Vince D

    2015-01-01

    Conventionally, structural topology is used for spatial normalization during the pre-processing of fMRI. The co-existence of multiple intrinsic networks which can be detected in the resting brain are well-studied. Also, these networks exhibit temporal and spatial modulation during cognitive task vs. rest which shows the existence of common spatial excitation patterns between these identified networks. Previous work (Khullar et al., 2011) has shown that structural and functional data may not have direct one-to-one correspondence and functional activation patterns in a well-defined structural region can vary across subjects even for a well-defined functional task. The results of this study and the existence of the neural activity patterns in multiple networks motivates us to investigate multiple resting-state networks as a single fusion template for functional normalization for multi groups of subjects. We extend the previous approach (Khullar et al., 2011) by co-registering multi group of subjects (healthy control and schizophrenia patients) and by utilizing multiple resting-state networks (instead of just one) as a single fusion template for functional normalization. In this paper we describe the initial steps toward using multiple resting-state networks as a single fusion template for functional normalization. A simple wavelet-based image fusion approach is presented in order to evaluate the feasibility of combining multiple functional networks. Our results showed improvements in both the significance of group statistics (healthy control and schizophrenia patients) and the spatial extent of activation when a multiple resting-state network applied as a single fusion template for functional normalization after the conventional structural normalization. Also, our results provided evidence that the improvement in significance of group statistics lead to better accuracy results for classification of healthy controls and schizophrenia patients. PMID:25873853

  13. Enhanced disease characterization through multi network functional normalization in fMRI

    PubMed Central

    Çetin, Mustafa S.; Khullar, Siddharth; Damaraju, Eswar; Michael, Andrew M.; Baum, Stefi A.; Calhoun, Vince D.

    2015-01-01

    Conventionally, structural topology is used for spatial normalization during the pre-processing of fMRI. The co-existence of multiple intrinsic networks which can be detected in the resting brain are well-studied. Also, these networks exhibit temporal and spatial modulation during cognitive task vs. rest which shows the existence of common spatial excitation patterns between these identified networks. Previous work (Khullar et al., 2011) has shown that structural and functional data may not have direct one-to-one correspondence and functional activation patterns in a well-defined structural region can vary across subjects even for a well-defined functional task. The results of this study and the existence of the neural activity patterns in multiple networks motivates us to investigate multiple resting-state networks as a single fusion template for functional normalization for multi groups of subjects. We extend the previous approach (Khullar et al., 2011) by co-registering multi group of subjects (healthy control and schizophrenia patients) and by utilizing multiple resting-state networks (instead of just one) as a single fusion template for functional normalization. In this paper we describe the initial steps toward using multiple resting-state networks as a single fusion template for functional normalization. A simple wavelet-based image fusion approach is presented in order to evaluate the feasibility of combining multiple functional networks. Our results showed improvements in both the significance of group statistics (healthy control and schizophrenia patients) and the spatial extent of activation when a multiple resting-state network applied as a single fusion template for functional normalization after the conventional structural normalization. Also, our results provided evidence that the improvement in significance of group statistics lead to better accuracy results for classification of healthy controls and schizophrenia patients. PMID:25873853

  14. Optimized time-resolved imaging of contrast kinetics (TRICKS) in dynamic contrast-enhanced MRI after peptide receptor radionuclide therapy in small animal tumor models.

    PubMed

    Haeck, Joost; Bol, Karin; Bison, Sander; van Tiel, Sandra; Koelewijn, Stuart; de Jong, Marion; Veenland, Jifke; Bernsen, Monique

    2015-11-01

    Anti-tumor efficacy of targeted peptide-receptor radionuclide therapy (PRRT) relies on several factors, including functional tumor vasculature. Little is known about the effect of PRRT on tumor vasculature. With dynamic contrast-enhanced (DCE-) MRI, functional vasculature is imaged and quantified using contrast agents. In small animals DCE-MRI is a challenging application. We optimized a clinical sequence for fast hemodynamic acquisitions, time-resolved imaging of contrast kinetics (TRICKS), to obtain DCE-MRI images at both high spatial and high temporal resolution in mice and rats. Using TRICKS, functional vasculature was measured prior to PRRT and longitudinally to investigate the effect of treatment on tumor vascular characteristics. Nude mice bearing H69 tumor xenografts and rats bearing syngeneic CA20948 tumors were used to study perfusion following PRRT administration with (177) lutetium octreotate. Both semi-quantitative and quantitative parameters were calculated. Treatment efficacy was measured by tumor-size reduction. Optimized TRICKS enabled MRI at 0.032 mm(3) voxel size with a temporal resolution of less than 5 s and large volume coverage, a substantial improvement over routine pre-clinical DCE-MRI studies. Tumor response to therapy was reflected in changes in tumor perfusion/permeability parameters. The H69 tumor model showed pronounced changes in DCE-derived parameters following PRRT. The rat CA20948 tumor model showed more heterogeneity in both treatment outcome and perfusion parameters. TRICKS enabled the acquisition of DCE-MRI at both high temporal resolution (Tres ) and spatial resolutions relevant for small animal tumor models. With the high Tres enabled by TRICKS, accurate pharmacokinetic data modeling was feasible. DCE-MRI parameters revealed changes over time and showed a clear relationship between tumor size and Ktrans . Copyright 2015 John Wiley & Sons, Ltd. PMID:25995102

  15. Distinguished Cooperating Teacher Program.

    ERIC Educational Resources Information Center

    Chicago State Univ., IL.

    The Distinguished Cooperating Teacher Program at Chicago State University was developed to train cooperating teachers to supervise student teachers. The program departs from traditional practice by changing the roles of the classroom teacher and the university field supervisor. The supervisor's role becomes that of coordinator while the teacher

  16. Molecular imaging of tumors and metastases using chemical exchange saturation transfer (CEST) MRI

    NASA Astrophysics Data System (ADS)

    Rivlin, Michal; Horev, Judith; Tsarfaty, Ilan; Navon, Gil

    2013-10-01

    The two glucose analogs 2-deoxy-D-glucose (2-DG) and 2-fluoro-2-deoxy-D-glucose (FDG) are preferentially taken up by cancer cells, undergo phosphorylation and accumulate in the cells. Owing to their exchangeable protons on their hydroxyl residues they exhibit significant chemical exchange saturation transfer (CEST) effect in MRI. Here we report CEST-MRI on mice bearing orthotopic mammary tumors injected with 2-DG or FDG. The tumor exhibited an enhanced CEST effect of up to 30% that persisted for over one hour. Thus 2-DG/FDG CEST MRI can replace PET/CT or PET/MRI for cancer research in laboratory animals, but also has the potential to be used in the clinic for the detection of tumors and metastases, distinguishing between malignant and benign tumors and monitoring tumor response to therapy as well as tumors metabolism noninvasively by using MRI, without the need for radio-labeled isotopes.

  17. Differentiation between multiple liver hemangiomas and liver metastases of gastrinomas: Value of enhanced MRI

    SciTech Connect

    Berger, J.F.; Laissy, J.P.; Limot, O.; Cadiot, G.

    1996-05-01

    Hepatic metastases of neuroendocrine tumors are known to mimic hemangiomas on nonenhanced SE MR sequences. The usefulness of MR examination with gadolinium injection to identify lesions was prospectively evaluated. Nine patients with multiple liver metastases of gastrinomas were compared with six patients showing multiple liver hemangiomas. Patients underwent unenhanced T2-weighted SE, T1-weighted SE, and FLASH sequences, followed by enhanced sequential FLASH sequences and a 5 min delayed T1-weighted SE sequence. On T2-weighted SE sequence, all hemangiomas displayed the same typical morphology as a sharply defined, homogeneous, high signal intensity lesion, but this pattern was also observed for some or all of the lesions in seven of nine patients with gastrinoma metastases. Dynamic FLASH sequences were accurate for lesions larger than 2 cm, hemangiomas displaying a nodular peripheral enhancement with centripetal filling in, and metastases displaying either an initial homogeneous or a regular peripheral enhancement. Precise assessment of lesions smaller than 2 cm remained equivocal. Delayed T1-weighted SE sequence (performed at least 5 min after Gd-chelate injection) was the most accurate technique to identify metastases by showing hypo-or isointensity signal, whereas all hemangiomas were hyperintense. Postcontrast delayed T1-weighted sequence is the primary technique to differentiate equivocal cases of hemangiomas from metastases of gastrinoma. 25 refs., 3 figs., 2 tabs.

  18. Dynamic Contrast-Enhanced MRI Parameters as Biomarkers in Assessing Head and Neck Lesions After Chemoradiotherapy Using a Wide-Bore 3 Tesla Scanner.

    PubMed

    Lerant, Gergely; Sarkozy, Peter; Takacsi-Nagy, Zoltan; Polony, Gabor; Tamas, Laszlo; Toth, Erika; Boer, Andras; Javor, Laszlo; Godeny, Maria

    2015-09-01

    Pilot studies have shown promising results in characterizing head and neck tumors (HNT) using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), differentiating between malignant and benign lesions and evaluating changes in response to chemoradiotherapy (CRT). Our aim was to find DCE-MRI parameters, biomarkers in evaluating the post-CRT status. Two hundred and five patients with head and neck lesions were examined with DCE-MRI sequences. The time intensity curves (TIC) were extracted and processed to acquire time-to-peak (TTP), relative maximum enhancement (RME), relative wash-out (RWO), and two new parameters attack and decay. These parameters were analyzed using univariate tests in SPSS (Statistical Package for the Social Sciences, version 17, SPSS Inc. Chicago, USA) to identify parameters that could be used to infer tumor malignancy and post-CRT changes. Multiple parameters of curve characteristics were significantly different between malignant tumors after CRT (MACRT) and changes caused by CRT. The best-performing biomarkers were the attack and the decay. We also found multiple significant (p < 0.05) parameters for both the benign and malignant status as well as pre- and post-CRT status. Our large cohort of data supports the increasing role of DCE-MRI in HNT differentiation, particularly for the assessment of post-CRT status along with accurate morphological imaging. PMID:25920367

  19. Therapeutic response assessment of RFA for HCC: Contrast-enhanced US, CT and MRI

    PubMed Central

    Minami, Yasunori; Nishida, Naoshi; Kudo, Masatoshi

    2014-01-01

    Radiofrequency ablation (RFA) is commonly applied for the treatment of hepatocellular carcinoma (HCC) because of the facile procedure, and the safety and effectiveness for the treatment of this type of tumor. On the other hand, it is believed that HCC cells should spread predominantly through the blood flow of the portal vein, which could lead to the formation of intrahepatic micrometastases. Therefore, monitoring tumor response after the treatment is quite important and accurate assessment of treatment response is critical to obtain the most favorable outcome after the RFA. Indeed, several reports suggested that even small HCCs of ≤ 3 cm in diameter might carry intrahepatic micrometastases and/or microvascular invasion. From this point of view, for preventing local recurrences, RFA should be performed ablating a main tumor as well as its surrounding non-tumorous liver tissue where micrometastases and microvascular invasion might exist. Recent advancement of imaging modalities such as contrast-enhanced ultrasonic, computed tomography, and magnetic resonance imaging are playing an important role on assessing the therapeutic effects of RFA. The local recurrence rate tends to be low in HCC patients who were proven to have adequate ablation margin after RFA; namely, not only disappearance of vascular enhancement of main tumor, but also an adequate ablation margin. Therefore, contrast enhancement gives important findings for the diagnosis of recurrent HCCs on each imaging. However, hyperemia of non-tumorous liver surrounding the ablated lesion, which could be attributed to an inflammation after RFA, may well obscure the findings of local recurrence of HCCs after RFA. Therefore, we need to carefully address to these imaging findings given the fact that diagnostic difficulties of local recurrence of HCC. Here, we give an overview of the current status of the imaging assessment of HCC response to RFA. PMID:24764654

  20. Intracranial Hypertension as an Acute Complication of Aseptic Meningoencephalitis with Leptomeningeal Contrast Enhancement on FLAIR MRI

    PubMed Central

    Wolf, Marc E.; Eisele, Philipp; Schweizer, Yvonne; Alonso, Angelika; Gass, Achim; Hennerici, Michael G.; Szabo, Kristina

    2016-01-01

    We report a case of a 19-year-old woman who developed intracranial hypertension as an unusual clinical complication of severe aseptic meningoencephalitis probably due to a diminished cerebrospinal fluid reabsorption capacity or leptomeningeal transudation as a consequence of blood-brain barrier dysfunction. These severe inflammatory changes were accompanied by prominent leptomeningeal contrast enhancement best visualized on fluid-attenuated inversion recovery magnetic resonance imaging. In such a prolonged course, a continuous lumbar drainage might be a temporary option to provide rapid symptom relief to the patient. PMID:26889150

  1. Intracranial Hypertension as an Acute Complication of Aseptic Meningoencephalitis with Leptomeningeal Contrast Enhancement on FLAIR MRI.

    PubMed

    Wolf, Marc E; Eisele, Philipp; Schweizer, Yvonne; Alonso, Angelika; Gass, Achim; Hennerici, Michael G; Szabo, Kristina

    2016-01-01

    We report a case of a 19-year-old woman who developed intracranial hypertension as an unusual clinical complication of severe aseptic meningoencephalitis probably due to a diminished cerebrospinal fluid reabsorption capacity or leptomeningeal transudation as a consequence of blood-brain barrier dysfunction. These severe inflammatory changes were accompanied by prominent leptomeningeal contrast enhancement best visualized on fluid-attenuated inversion recovery magnetic resonance imaging. In such a prolonged course, a continuous lumbar drainage might be a temporary option to provide rapid symptom relief to the patient. PMID:26889150

  2. Simultaneous Measurement of Kidney Function by Dynamic Contrast Enhanced MRI and FITC-Sinistrin Clearance in Rats at 3 Tesla: Initial Results

    PubMed Central

    Bcker, Sandra; Neudecker, Sabine; Gretz, Norbert; Schad, Lothar R.

    2013-01-01

    Glomerular filtration rate (GFR) is an essential parameter of kidney function which can be measured by dynamic contrast enhanced magnetic resonance imaging (MRI-GFR) and transcutaneous approaches based on fluorescent tracer molecules (optical-GFR). In an initial study comparing both techniques in separate measurements on the same animal, the correlation of the obtained GFR was poor. The goal of this study was to investigate if a simultaneous measurement was feasible and if thereby, the discrepancies in MRI-GFR and optical-GFR could be reduced. For the experiments healthy and unilateral nephrectomised (UNX) Sprague Dawley (SD) rats were used. The miniaturized fluorescent sensor was fixed on the depilated back of an anesthetized rat. A bolus of 5 mg/100 g b.w. of FITC-sinistrin was intravenously injected. For dynamic contrast enhanced perfusion imaging (DCE-MRI) a 3D time-resolved angiography with stochastic trajectories (TWIST) sequence was used. By means of a one compartment model the excretion half-life (t1/2) of FITC-sinistrin was calculated and converted into GFR. GFR from DCE-MRI was calculated by fitting pixel-wise a two compartment renal filtration model. Mean cortical GFR and GFR by FITC-sinistrin were compared by Bland-Altman plots and pair-wise t-test. Results show that a simultaneous GFR measurement using both techniques is feasible. Mean optical-GFR was 4.342.22 ml/min (healthy SD rats) and 2.340.90 ml/min (UNX rats) whereas MRI-GFR was 2.100.64 ml/min (SD rats) and 1.170.38 ml/min (UNX rats). Differences between healthy and UNX rats were significant (p<0.05) and almost equal percentage difference (46.1% and 44.3%) in mean GFR were assessed with both techniques. Overall mean optical-GFR values were approximately twice as high compared to MRI-GFR values. However, compared to a previous study, our results showed a higher agreement. In conclusion, the possibility to use the transcutaneous method in MRI may have a huge impact in improving and validating MRI methods for GFR assessment in animal models. PMID:24260332

  3. Reduced hippocampal manganese-enhanced MRI (MEMRI) signal during pilocarpine-induced status epilepticus: edema or apoptosis?

    PubMed

    Malheiros, Jackeline Moraes; Persike, Daniele Suzete; Castro, Leticia Urbano Cardoso de; Sanches, Talita Rojas Cunha; Andrade, Lúcia da Conceição; Tannús, Alberto; Covolan, Luciene

    2014-05-01

    Manganese-enhanced MRI (MEMRI) has been considered a surrogate marker of Ca(+2) influx into activated cells and tracer of neuronal active circuits. However, the induction of status epilepticus (SE) by kainic acid does not result in hippocampal MEMRI hypersignal, in spite of its high cell activity. Similarly, short durations of status (5 or 15min) induced by pilocarpine did not alter the hippocampal MEMRI, while 30 min of SE even reduced MEMRI signal Thus, this study was designed to investigate possible explanations for the absence or decrease of MEMRI signal after short periods of SE. We analyzed hippocampal caspase-3 activation (to evaluate apoptosis), T2 relaxometry (tissue water content) and aquaporin 4 expression (water-channel protein) of rats subjected to short periods of pilocarpine-induced SE. For the time periods studied here, apoptotic cell death did not contribute to the decrease of the hippocampal MEMRI signal. However, T2 relaxation was higher in the group of animals subjected to 30min of SE than in the other SE or control groups. This result is consistent with higher AQP-4 expression during the same time period. Based on apoptosis and tissue water content analysis, the low hippocampal MEMRI signal 30min after SE can potentially be attributed to local edema rather than to cell death. PMID:24630048

  4. [Amyloid beta-related angiitis: brain lesions showing leptomeningeal gadolinium enhancement on MRI and characteristic surgical pathologic features].

    PubMed

    Koike, Yuka; Ouchi, Haruka; Sato, Tomoe; Shimbo, Junsuke; Sato, Aki; Sasaki, Osamu; Shibuya, Hiroyuki; Okamoto, Kouichirou; Kakita, Akiyoshi; Igarashi, Shuichi

    2013-06-01

    Amyloid-?-related angiitis (ABRA) of the CNS occurs in association with vasculitis of small-and medium-sized leptomeningeal arteries. Here, we describe the clinicopathological features of a 76-year-old man with ABRA. The patient suffered progressive truncal oscillation, aphasia, and recent memory disturbance with a subacute disease onset. His cerebrospinal fluid showed a mild increase in protein levels (101 mg/dL) and pleocytosis (8/mm(3)). High-intensity brain lesion were detected on T(2)-weighted and FLAIR MRI scans, and prominent spread of gadolinium enhancement spreading was observed through the sulci of the left occipital and temporal lobes and left cerebellar hemisphere. A biopsy of the left temporal lesion showed a granulomatous and angiodestructive inflammation with infiltration of many CD4(+) T-lymphocytes and multinucleated giant cells and with fibrinoid necrosis of the arterial walls in the subarachnoid space. Immunolabeling for A?(1-40) revealed the abundant deposition of this protein in the affected arteries. On the basic of the diagnosis of ABRA, immunosuppressive therapy was conducted, and it ameliorated the clinical course. PMID:23735532

  5. Connectivity-based fixel enhancement: Whole-brain statistical analysis of diffusion MRI measures in the presence of crossing fibres.

    PubMed

    Raffelt, David A; Smith, Robert E; Ridgway, Gerard R; Tournier, J-Donald; Vaughan, David N; Rose, Stephen; Henderson, Robert; Connelly, Alan

    2015-08-15

    In brain regions containing crossing fibre bundles, voxel-average diffusion MRI measures such as fractional anisotropy (FA) are difficult to interpret, and lack within-voxel single fibre population specificity. Recent work has focused on the development of more interpretable quantitative measures that can be associated with a specific fibre population within a voxel containing crossing fibres (herein we use fixel to refer to a specific fibre population within a single voxel). Unfortunately, traditional 3D methods for smoothing and cluster-based statistical inference cannot be used for voxel-based analysis of these measures, since the local neighbourhood for smoothing and cluster formation can be ambiguous when adjacent voxels may have different numbers of fixels, or ill-defined when they belong to different tracts. Here we introduce a novel statistical method to perform whole-brain fixel-based analysis called connectivity-based fixel enhancement (CFE). CFE uses probabilistic tractography to identify structurally connected fixels that are likely to share underlying anatomy and pathology. Probabilistic connectivity information is then used for tract-specific smoothing (prior to the statistical analysis) and enhancement of the statistical map (using a threshold-free cluster enhancement-like approach). To investigate the characteristics of the CFE method, we assessed sensitivity and specificity using a large number of combinations of CFE enhancement parameters and smoothing extents, using simulated pathology generated with a range of test-statistic signal-to-noise ratios in five different white matter regions (chosen to cover a broad range of fibre bundle features). The results suggest that CFE input parameters are relatively insensitive to the characteristics of the simulated pathology. We therefore recommend a single set of CFE parameters that should give near optimal results in future studies where the group effect is unknown. We then demonstrate the proposed method by comparing apparent fibre density between motor neurone disease (MND) patients with control subjects. The MND results illustrate the benefit of fixel-specific statistical inference in white matter regions that contain crossing fibres. PMID:26004503

  6. Connectivity-based fixel enhancement: Whole-brain statistical analysis of diffusion MRI measures in the presence of crossing fibres

    PubMed Central

    Raffelt, David A.; Smith, Robert E.; Ridgway, Gerard R.; Tournier, J-Donald; Vaughan, David N.; Rose, Stephen; Henderson, Robert; Connelly, Alan

    2015-01-01

    In brain regions containing crossing fibre bundles, voxel-average diffusion MRI measures such as fractional anisotropy (FA) are difficult to interpret, and lack within-voxel single fibre population specificity. Recent work has focused on the development of more interpretable quantitative measures that can be associated with a specific fibre population within a voxel containing crossing fibres (herein we use fixel to refer to a specific fibre population within a single voxel). Unfortunately, traditional 3D methods for smoothing and cluster-based statistical inference cannot be used for voxel-based analysis of these measures, since the local neighbourhood for smoothing and cluster formation can be ambiguous when adjacent voxels may have different numbers of fixels, or ill-defined when they belong to different tracts. Here we introduce a novel statistical method to perform whole-brain fixel-based analysis called connectivity-based fixel enhancement (CFE). CFE uses probabilistic tractography to identify structurally connected fixels that are likely to share underlying anatomy and pathology. Probabilistic connectivity information is then used for tract-specific smoothing (prior to the statistical analysis) and enhancement of the statistical map (using a threshold-free cluster enhancement-like approach). To investigate the characteristics of the CFE method, we assessed sensitivity and specificity using a large number of combinations of CFE enhancement parameters and smoothing extents, using simulated pathology generated with a range of test-statistic signal-to-noise ratios in five different white matter regions (chosen to cover a broad range of fibre bundle features). The results suggest that CFE input parameters are relatively insensitive to the characteristics of the simulated pathology. We therefore recommend a single set of CFE parameters that should give near optimal results in future studies where the group effect is unknown. We then demonstrate the proposed method by comparing apparent fibre density between motor neurone disease (MND) patients with control subjects. The MND results illustrate the benefit of fixel-specific statistical inference in white matter regions that contain crossing fibres. PMID:26004503

  7. Breast MRI fibroglandular volume and parenchymal enhancement in BRCA1 and BRCA2 mutation carriers before and immediately after risk-reducing salpingo-oophorectomy.

    PubMed

    DeLeo, Michael J; Domchek, Susan M; Kontos, Despina; Conant, Emily; Chen, Jinbo; Weinstein, Susan

    2015-03-01

    OBJECTIVE. The purpose of this article is to assess the difference in fibroglandular volume and background parenchymal enhancement in BRCA1 and BRCA2 mutation carriers on contrast-enhanced breast MRI (CE-MRI) performed before and immediately after risk-reducing salpingo-oophorectomy (RRSO). MATERIALS AND METHODS. We retrospectively compared fibroglandular volume and background parenchymal enhancement in 55 female BRCA1 and BRCA2 mutation carriers before and after RRSO using standard BI-RADS categories and a paired Wilcoxon and Mann-Whitney U test. A two-sample Wilcoxon test was performed to compare fibroglandular volume and background parenchymal enhancement in women with and without subsequent breast cancer diagnosis on follow-up. RESULTS. The median time to post-RRSO CE-MRI was 8 months (range, 1-40 months). There was no difference in fibroglandular volume before and after RRSO (p = 0.65). The mean background parenchymal enhancement was 2.5 (range, 1-4) before and 1.5 (range, 1-4) after RRSO (overall range, -2.5 to 1.5; p = 0.0001). Breast cancer was detected in nine women at a median time of 4.8 years (range, 1.8-13.3 years) after RRSO. For women who received a diagnosis of breast cancer after RRSO compared with those who did not, mean background parenchymal enhancement before RRSO was 3 (range, 2-4) versus 2.5 (range, 1-4; p = 0.001), and mean background parenchymal enhancement after RRSO was 2.5 (range, 1.5-4) versus 1.5 (range 2-4; p = 0.0018). There was no difference in fibroglandular volume before and after RRSO. CONCLUSION. In BRCA1 and BRCA2 mutation carriers, we observed a significant reduction in background parenchymal enhancement on the first CE-MRI after RRSO and no significant change in fibroglandular volume. Higher background parenchymal enhancement before and after RRSO was observed in women who subsequently received a diagnosis of breast cancer. This suggests that background parenchymal enhancement, rather than fibro-glandular volume, may be a more sensitive imaging biomarker of breast cancer risk. PMID:25714301

  8. Manganese-enhanced MRI of rat brain based on slow cerebral delivery of manganese(II) with silica-encapsulated Mn x Fe(1-x) O nanoparticles.

    PubMed

    Chen, Wei; Lu, Fang; Chen, Chiao-Chi V; Mo, Kuan-Chi; Hung, Yann; Guo, Zhi-Xuan; Lin, Chia-Hui; Lin, Ming-Huang; Lin, Yu-Hsuan; Chang, Chen; Mou, Chung-Yuan

    2013-09-01

    In this work, we report a monodisperse bifunctional nanoparticle system, MIO@SiO2 -RITC, as an MRI contrast agent [core, manganese iron oxide (MIO); shell, amorphous silica conjugated with rhodamine B isothiocyanate (RITC)]. It was prepared by thermal decomposition and modified microemulsion methods. The nanoparticles with varying iron to manganese ratios displayed different saturated magnetizations and relaxivities. In vivo MRI of rats injected intravenously with MIO@SiO2-RITC nanoparticles exhibited enhancement of the T1 contrast in brain tissue, in particular a time-delayed enhancement in the hippocampus, pituitary gland, striatum and cerebellum. This is attributable to the gradual degradation of MIO@SiO2-RITC nanoparticles in the liver, resulting in the slow release of manganese(II) [Mn(II)] into the blood pool and, subsequently, accumulation in the brain tissue. Thus, T1-weighted contrast enhancement was clearly detected in the anatomic structure of the brain as time progressed. In addition, T2*-weighted images of the liver showed a gradual darkening effect. Here, we demonstrate the concept of the slow release of Mn(II) for neuroimaging. This new nanoparticle-based manganese contrast agent allows one simple intravenous injection (rather than multiple infusions) of Mn(II) precursor, and results in delineation of the detailed anatomic neuroarchitecture in MRI; hence, this provides the advantage of the long-term study of neural function. PMID:23526743

  9. Sensitivity-enhanced chemical exchange saturation transfer (CEST) MRI with least squares optimization of Carr Purcell Meiboom Gill multi-echo echo planar imaging

    PubMed Central

    Sun, Phillip Zhe; Wang, Yu; Lu, Jie

    2014-01-01

    Chemical exchange saturation transfer (CEST) imaging is a novel MRI technique that is sensitive to biomolecules, local pH and temperature, and offers considerable advantages for in vivo applications. However, the magnitude of CEST effect for dilute CEST agents undergoing slow or intermediate chemical exchange is typically small, requiring the use of signal averaging to enhance its sensitivity. Given that T2-induced signal loss can be normalized by asymmetry analysis, the magnitude of CEST effect is independent of echo time. Therefore, CEST imaging with multi-echo echo planar imaging (EPI) readout should yield the same CEST effect as conventional single echo acquisition. Importantly, CEST multi-echo (CESTme) EPI images can be averaged to enhance CEST MRI sensitivity. The goal of this study was to validate CESTme EPI using a creatine-agarose gel CEST phantom with similar T2 as biological tissue. Using least-squares optimization, we found that the sensitivity of CESTme sequence is significantly higher than that obtained by conventional single echo CEST-EPI acquisition. Specifically, signal to noise ratio (SNR) and contrast to noise ratio (CNR) from the proposed CESTme EPI were approximately equivalent to that obtained by doubling the number of signal averages of the standard single echo CEST MRI sequence. In summary, our results demonstrate CESTme EPI for sensitivity-enhanced CEST imaging. PMID:24523063

  10. Dynamic Contrast-Enhanced MRI of Gd-albumin Delivery to the Rat Hippocampus In Vivo by Convection-Enhanced Delivery

    PubMed Central

    Kim, Jung Hwan; Astary, Garrett W.; Nobrega, Tatiana L.; Kantorovich, Svetlana; Carney, Paul R.; Mareci, Thomas H.; Sarntinoranont, Malisa

    2013-01-01

    Convection enhanced delivery (CED) shows promise in treating neurological diseases due to its ability to circumvent the blood-brain barrier (BBB) and deliver therapeutics directly to the parenchyma of the central nervous system (CNS). Such a drug delivery method may be useful in treating CNS disorders involving the hippocampus such temporal lobe epilepsy and gliomas; however, the influence of anatomical structures on infusate distribution is not fully understood. As a surrogate for therapeutic agents, we used gadolinium-labeled-albumin (Gd-albumin) tagged with Evans blue dye to observe the time dependence of CED infusate distributions into the rat dorsal and ventral hippocampus in vivo with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). For finer anatomical detail, final distribution volumes (Vd) of the infusate were observed with high-resolution T1-weighted MR imaging and light microscopy of fixed brain sections. Dynamic images demonstrated that Gd-albumin preferentially distributed within the hippocampus along neuroanatomical structures with less fluid resistance and less penetration was observed in dense cell layers. Furthermore, significant leakage into adjacent cerebrospinal fluid (CSF) spaces such as the hippocampal fissure, velum interpositum and midbrain cistern occurred toward the end of infusion. Vd increased linearly with infusion volume (Vi) at a mean Vd/Vi ratio of 5.51 0.55 for the dorsal hippocampus infusion and 5.30 0.83 for the ventral hippocampus infusion. This study demonstrated the significant effects of tissue structure and CSF space boundaries on infusate distribution during CED. PMID:22687936

  11. Live nephron imaging by MRI.

    PubMed

    Qian, Chunqi; Yu, Xin; Pothayee, Nikorn; Dodd, Stephen; Bouraoud, Nadia; Star, Robert; Bennett, Kevin; Koretsky, Alan

    2014-11-15

    The local sensitivity of MRI can be improved with small MR detectors placed close to regions of interest. However, to maintain such sensitivity advantage, local detectors normally need to communicate with the external amplifier through cable connections, which prevent the use of local detectors as implantable devices. Recently, an integrated wireless amplifier was developed that can efficiently amplify and broadcast locally detected signals, so that the local sensitivity was enhanced without the need for cable connections. This integrated detector enabled the live imaging of individual glomeruli using negative contrast introduced by cationized ferritin, and the live imaging of renal tubules using positive contrast introduced by gadopentetate dimeglumine. Here, we utilized the high blood flow to image individual glomeruli as hyperintense regions without any contrast agent. These hyperintense regions were identified for pixels with signal intensities higher than the local average. Addition of Mn(2+) allowed the simultaneous detection of both glomeruli and renal tubules: Mn(2+) was primarily reabsorbed by renal tubules, which would be distinguished from glomeruli due to higher enhancement in T1-weighted MRI. Dynamic studies of Mn(2+) absorption confirmed the differential absorption affinity of glomeruli and renal tubules, potentially enabling the in vivo observation of nephron function. PMID:25186296

  12. Chance and limit of imaging of articular cartilage in vitro in healthy and arthritic joints: DEI (diffraction enhanced imaging) in comparison with MRI, CT, and ultrasound

    NASA Astrophysics Data System (ADS)

    Wagner, Andreas F.; Aurich, Matthias; Stoessel, Marco; Sieber, Norbert; Wetzel, Wolf-Dieter; Mollenhauer, Jurgen; Schmuck, Klaus; Muehleman, Carol; Lohmann, Michael; Reime, Bernd; Metge, Joachim; Coan, Paola; Bravin, Alberto; Arfelli, Fulvia; Rigon, Luigi; Menk, Ralf-Henrik

    2005-04-01

    Description of purpose: Treatment of osteoarthritis in stages of reversible disease requires high resolution visualization of early cartilage damage and of subchondral bone. Here, DEI (Diffraction Enhanced Imaging) is compared to MRI, computed X-ray tomography (CT) and ultrasound (UI) in its ability to detect early degeneration of articular cartilage. In contrast to conventional absorptive X-ray examination where cartilage is poorly visible DEI captures cartilage by detection of selected refraction. Methods: Human femoral heads were investigated by macroscopic inspection, conventional X-ray examination, DEI, MRI, CT, UI and histology. DEI is an imaging technique applying a monochromatic parallel synchrotron X-ray beam. Image features were verified by histology. Results: DEI, MRI and ultrasound lead to interpretable images of cartilage. Of all techniques, DEI provided highest image resolution revealing the structural tissue architecture. MRI needs a very long exposure time (more than 5 hours) to achieve comparable quality. Application of ultrasound is limited because of joint geometry and, at high sound frequency, the necessity of close contact between cartilage and transducer. DEI is an experimental technique which needs synchrotron radiation. Conclusion: DEI is a very promising imaging technique for visualization of cartilage and bone. It may serve as an excellent analytical tool for experimental studies. Our pictures show a part of future of optimised techniques for imaging. Synchrotron based DEI may lead the way towards optimisation of improved techniques for imaging. Upon development of adequate small scale X-ray sources, DEI will also be an important supplementation for medical imaging.

  13. Chest MRI

    MedlinePLUS

    ... from the NHLBI on Twitter. What Is Chest MRI? Chest MRI (magnetic resonance imaging) is a safe, noninvasive test. "Noninvasive" means that ... your chest wall, heart, and blood vessels. Chest MRI uses radio waves, magnets, and a computer to ...

  14. Cocaine-induced locomotor sensitization in rats correlates with nucleus accumbens activity on manganese-enhanced MRI.

    PubMed

    Perrine, Shane A; Ghoddoussi, Farhad; Desai, Kirtan; Kohler, Robert J; Eapen, Ajay T; Lisieski, Michael J; Angoa-Perez, Mariana; Kuhn, Donald M; Bosse, Kelly E; Conti, Alana C; Bissig, David; Berkowitz, Bruce A

    2015-11-01

    A long-standing goal of substance abuse research has been to link drug-induced behavioral outcomes with the activity of specific brain regions to understand the neurobiology of addiction behaviors and to search for drug-able targets. Here, we tested the hypothesis that cocaine produces locomotor (behavioral) sensitization that correlates with increased calcium channel-mediated neuroactivity in brain regions linked with drug addiction, such as the nucleus accumbens (NAC), anterior striatum (AST) and hippocampus, as measured using manganese-enhanced MRI (MEMRI). Rats were treated with cocaine for 5 days, followed by a 2-day drug-free period. The following day, locomotor sensitization was quantified as a metric of cocaine-induced neuroplasticity in the presence of manganese. Immediately following behavioral testing, rats were examined for changes in calcium channel-mediated neuronal activity in the NAC, AST, hippocampus and temporalis muscle, which was associated with behavioral sensitization using MEMRI. Cocaine significantly increased locomotor activity and produced behavioral sensitization compared with saline treatment of control rats. A significant increase in MEMRI signal intensity was determined in the NAC, but not AST or hippocampus, of cocaine-treated rats compared with saline-treated control rats. Cocaine did not increase signal intensity in the temporalis muscle. Notably, in support of our hypothesis, behavior was significantly and positively correlated with MEMRI signal intensity in the NAC. As neuronal uptake of manganese is regulated by calcium channels, these results indicate that MEMRI is a powerful research tool to study neuronal activity in freely behaving animals and to guide new calcium channel-based therapies for the treatment of cocaine abuse and dependence. PMID:26411897

  15. Quantitative assessment of regional cerebral blood flow by dynamic susceptibility contrast-enhanced MRI, without the need for arterial blood signals

    NASA Astrophysics Data System (ADS)

    Enmi, Jun-ichiro; Kudomi, Nobuyuki; Hayashi, Takuya; Yamamoto, Akihide; Iguchi, Satoshi; Moriguchi, Tetsuaki; Hori, Yuki; Koshino, Kazuhiro; Zeniya, Tsutomu; Shah, Nadim Jon; Yamada, Naoaki; Iida, Hidehiro

    2012-12-01

    In dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI), an arterial input function (AIF) is usually obtained from a time-concentration curve (TCC) of the cerebral artery. This study was aimed at developing an alternative technique for reconstructing AIF from TCCs of multiple brain regions. AIF was formulated by a multi-exponential function using four parameters, and the parameters were determined so that the AIF curves convolved with a model of tissue response reproduced the measured TCCs for 20 regions. Systematic simulations were performed to evaluate the effects of possible error sources. DSC-MRI and positron emission tomography (PET) studies were performed on 14 patients with major cerebral artery occlusion. Cerebral blood flow (CBF) images were calculated from DSC-MRI data, using our novel method alongside conventional AIF estimations, and compared with those from 15O-PET. Simulations showed that the calculated CBF values were sensitive to variations in the assumptions regarding cerebral blood volume. Nevertheless, AIFs were reasonably reconstructed for all patients. The difference in CBF values between DSC-MRI and PET was -2.2 7.4 ml/100 g/min (r = 0.55, p < 0.01) for our method, versus -0.2 8.2 ml/100 g/min (r = 0.47, p = 0.01) for the conventional method. The difference in the ratio of affected to unaffected hemispheres between DSC-MRI and PET was 0.07 0.09 (r = 0.82, p < 0.01) for our method, versus 0.07 0.09 (r = 0.83, p < 0.01) for the conventional method. The contrasts in CBF images from our method were the same as those from the conventional method. These findings suggest the feasibility of assessing CBF without arterial blood signals.

  16. Multi-Parametric MRI and Texture Analysis to Visualize Spatial Histologic Heterogeneity and Tumor Extent in Glioblastoma

    PubMed Central

    Hu, Leland S.; Ning, Shuluo; Eschbacher, Jennifer M.; Gaw, Nathan; Dueck, Amylou C.; Smith, Kris A.; Nakaji, Peter; Plasencia, Jonathan; Ranjbar, Sara; Price, Stephen J.; Tran, Nhan; Loftus, Joseph; Jenkins, Robert; O’Neill, Brian P.; Elmquist, William; Baxter, Leslie C.; Gao, Fei; Frakes, David; Karis, John P.; Zwart, Christine; Swanson, Kristin R.; Sarkaria, Jann; Wu, Teresa

    2015-01-01

    Background Genetic profiling represents the future of neuro-oncology but suffers from inadequate biopsies in heterogeneous tumors like Glioblastoma (GBM). Contrast-enhanced MRI (CE-MRI) targets enhancing core (ENH) but yields adequate tumor in only ~60% of cases. Further, CE-MRI poorly localizes infiltrative tumor within surrounding non-enhancing parenchyma, or brain-around-tumor (BAT), despite the importance of characterizing this tumor segment, which universally recurs. In this study, we use multiple texture analysis and machine learning (ML) algorithms to analyze multi-parametric MRI, and produce new images indicating tumor-rich targets in GBM. Methods We recruited primary GBM patients undergoing image-guided biopsies and acquired pre-operative MRI: CE-MRI, Dynamic-Susceptibility-weighted-Contrast-enhanced-MRI, and Diffusion Tensor Imaging. Following image coregistration and region of interest placement at biopsy locations, we compared MRI metrics and regional texture with histologic diagnoses of high- vs low-tumor content (≥80% vs <80% tumor nuclei) for corresponding samples. In a training set, we used three texture analysis algorithms and three ML methods to identify MRI-texture features that optimized model accuracy to distinguish tumor content. We confirmed model accuracy in a separate validation set. Results We collected 82 biopsies from 18 GBMs throughout ENH and BAT. The MRI-based model achieved 85% cross-validated accuracy to diagnose high- vs low-tumor in the training set (60 biopsies, 11 patients). The model achieved 81.8% accuracy in the validation set (22 biopsies, 7 patients). Conclusion Multi-parametric MRI and texture analysis can help characterize and visualize GBM’s spatial histologic heterogeneity to identify regional tumor-rich biopsy targets. PMID:26599106

  17. Automated analysis of non-mass-enhancing lesions in breast MRI based on morphological, kinetic, and spatio-temporal moments and joint segmentation-motion compensation technique

    NASA Astrophysics Data System (ADS)

    Hoffmann, Sebastian; Shutler, Jamie D.; Lobbes, Marc; Burgeth, Bernhard; Meyer-Bse, Anke

    2013-12-01

    Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) represents an established method for the detection and diagnosis of breast lesions. While mass-like enhancing lesions can be easily categorized according to the Breast Imaging Reporting and Data System (BI-RADS) MRI lexicon, a majority of diagnostically challenging lesions, the so called non-mass-like enhancing lesions, remain both qualitatively as well as quantitatively difficult to analyze. Thus, the evaluation of kinetic and/or morphological characteristics of non-masses represents a challenging task for an automated analysis and is of crucial importance for advancing current computer-aided diagnosis (CAD) systems. Compared to the well-characterized mass-enhancing lesions, non-masses have no well-defined and blurred tumor borders and a kinetic behavior that is not easily generalizable and thus discriminative for malignant and benign non-masses. To overcome these difficulties and pave the way for novel CAD systems for non-masses, we will evaluate several kinetic and morphological descriptors separately and a novel technique, the Zernike velocity moments, to capture the joint spatio-temporal behavior of these lesions, and additionally consider the impact of non-rigid motion compensation on a correct diagnosis.

  18. Can silicene distinguish nucleobases?

    NASA Astrophysics Data System (ADS)

    Scheicher, Ralph Hendrik; Amorim, Rodrigo G.

    2014-03-01

    The third generation of DNA sequencing devices are on the drawing board of industry and solid-state devices appear to be most promising for this task. In view of the silicon-based semiconductor industry it is noteworthy that a 2D allotrope of silicon was recently discovered, silicene, which resembles graphene in certain aspects. Given the prevalence of proposals to utilize graphene for DNA sequencing, we therefore chose to investigate the hypothesis whether a solid-state device based on silicene (which might be more straightforward to integrate with existing semiconductor technology) could electrically distinguish the four nucleobases in DNA. For this purpose, we used ab initio calculations based on density functional theory combined with the non-equilibrium Green's function method to study the electronic transport properties of a silicene sheet interacting with the constituents of DNA. We will present a detailed study of the physisorption process of the nucleobases on top of silicene, as well as how the adsorbed nucleobases would appear in a scanning tunneling microscope (STM) image. The key result that we will discuss is how the zero-bias transmittance of pristine silicene is altered when a specific nucleobase is adsorbed on its surface.

  19. Noninvasive monitoring of radiotherapy-induced microvascular changes using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) in a colorectal tumor model

    SciTech Connect

    Ceelen, Wim . E-mail: Wim.ceelen@ugent.be; Smeets, Peter; Backes, Walter; Van Damme, Nancy; Boterberg, Tom; Demetter, Pieter; Bouckenooghe, Isabel; De Visschere, Marieke; Peeters, Marc; Pattyn, Piet

    2006-03-15

    Purpose: To examine dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with a macromolecular contrast agent (P792) to visualize effects of radiotherapy (RT) on microvascular leakage in a colorectal cancer model. Methods and Materials: CC531 tumors were induced in WAG/Rij rats. DCE-MRI was performed before and 5 days after 5 x 5 Gy of RT and parametric maps generated of the endothelial transfer constant (K{sup trans} ) and the fractional interstitial space (V{sub e} ) according to the Tofts model. Tissue pO{sub 2} mapping was performed in each tumor core and rim before and after RT. Microvessel density (MVD), vascular endothelial growth factor (VEGF) expression, and pimonidazole hypoxia staining were compared with a control group of tumor-bearing rats. Results: Mean K{sup trans} and v{sub e} were significantly reduced after RT in all tumor regions. Mean pO{sub 2} was 6.8 mm Hg before RT vs. 7.7 mm Hg after RT (p < 0.001) in the tumor rim and 3.5 mm Hg before RT vs. 4.4 mm Hg after RT (p < 0.001) in the tumor core. Mean MVD in the tumor rim was 10.4 in the RT treated group vs. 16.9 in the control group (p = 0.061). VEGF expression was significantly higher in RT-treated rats. After RT, no correlation was found between DCE-MRI parameters and histologic parameters. A correlation was seen after RT between pO{sub 2} and K{sup trans} (r -0.57, p = 0.08) and between pO{sub 2} and v{sub e} (r = -0.65, p = 0.04). Conclusions: Dynamic contrast-enhanced-MRI with P792 allows quantification of microvascular changes in this colorectal model. RT significantly reduces neovascular leakage and enhances tissue oxygenation and VEGF expression. After RT, DCE-MRI parameters are related to tumor pO{sub 2}, but not to MVD or VEGF expression.

  20. Gadoxetic Acid-Enhanced MRI and Sonoelastography: Non-Invasive Assessments of Chemoprevention of Liver Fibrosis in Thioacetamide-Induced Rats with Sho-Saiko-To

    PubMed Central

    Chen, Ya-Wen; Tsai, Meng-Yuan; Pan, Huay-Ben; Tseng, Hui-Hwa; Hung, Yu-Ting; Chou, Chen-Pin

    2014-01-01

    Background This study aimed to compare the performance of gadoxetic acid -enhanced magnetic resonance imaging (MRI) and sonoelastography in evaluating chemopreventive effects of Sho-Saiko-To (SST) in thioacetamide (TAA)-induced early liver fibrosis in rats. Materials and Methods Ten of Sprague-Dawley rats receiving TAA (200 mg/kg of body weight) intraperitoneal injection were divided into three groups: Group 1 (TAA only, n?=?3), Group 2 (TAA +0.25 g/kg SST, n?=?4) and Group 3 (TAA+1 g/kg SST, n?=?3). Core needle liver biopsy at week 2 and liver specimens after sacrifice at week 6 confirmed liver fibrosis using histological examinations, including Sirius red staining, Ishak and Metavir scoring systems. Gadoxetic acid-enhanced MRI and shear-wave sonoelastography were employed to evaluate liver fibrosis. The expression of hepatic transporter organic anion transporter 1 (Oatp1), multidrug-resistant protein 2 (Mrp2) and alpha-smooth muscle actin (?-Sma) were also analyzed in each group by immunohistochemistry (IHC) and Western blot. Results According to histological grading by Sirius red staining, Ishak scores of liver fibrosis in Groups 1, 2 and 3 were 3, 2 and 1, respectively. As shown in gadoxetic acid-enhanced MRI, the ratio of relative enhancement was significantly lower in Group 1 (1.870.21) than in Group 2 of low-dose (2.820.25) and Group 3 of high-dose (2.720.12) SST treatment at 10 minutes after gadoxetic acid intravenous injection (p<0.05). Sonoelastography showed that the mean difference before and after experiments in Groups 1, 2 and 3 were 4.660.1, 4.40.57 and 30.4 KPa (p<0.1), respectively. Chemopreventive effects of SST reduced the Mrp2 protein level (p<0.01) but not Oatp1 and ?-Sma levels. Conclusion Sonoelastography and gadoxetic acid-enhanced MRI could monitor the treatment effect of SST in an animal model of early hepatic fibrosis. PMID:25490034

  1. 7T MRI in natalizumab-associated PML and ongoing MS disease activity

    PubMed Central

    Sinnecker, Tim; Othman, Jalal; Kühl, Marc; Mekle, Ralf; Selbig, Inga; Niendorf, Thoralf; Kunkel, Annett; Wienecke, Peter; Kern, Peter; Faiss, Juergen; Wuerfel, Jens

    2015-01-01

    Objective: To assess the ability of ultra-high-field MRI to distinguish early progressive multifocal leukoencephalopathy (PML) from multiple sclerosis (MS) lesions in a rare case of simultaneous presentation of natalizumab–associated PML and ongoing MS activity. Methods: Advanced neuroimaging including 1.5T, 3T, and 7T MRI with a spatial resolution of up to 0.08 mm3 was performed. Results: 7T MRI differentiated between PML-related and MS-related brain damage in vivo. Ring-enhancing MS plaques displayed a central vein, whereas confluent PML lesions were preceded by punctate or milky way–like T2 lesions. Conclusions: Given the importance of early diagnosis of treatment-associated PML, future systematic studies are warranted to assess the value of highly resolving MRI in differentiating between early PML- and MS-induced brain parenchymal lesions. PMID:26568970

  2. 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 ?L 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 ?L 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 ?L 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.

  3. Automatic classification of scar tissue in late gadolinium enhancement cardiac MRI for the assessment of left-atrial wall injury after radiofrequency ablation

    NASA Astrophysics Data System (ADS)

    Perry, Daniel; Morris, Alan; Burgon, Nathan; McGann, Christopher; MacLeod, Robert; Cates, Joshua

    2012-03-01

    Radiofrequency ablation is a promising procedure for treating atrial fibrillation (AF) that relies on accurate lesion delivery in the left atrial (LA) wall for success. Late Gadolinium Enhancement MRI (LGE MRI) at three months post-ablation has proven effective for noninvasive assessment of the location and extent of scar formation, which are important factors for predicting patient outcome and planning of redo ablation procedures. We have developed an algorithm for automatic classification in LGE MRI of scar tissue in the LA wall and have evaluated accuracy and consistency compared to manual scar classifications by expert observers. Our approach clusters voxels based on normalized intensity and was chosen through a systematic comparison of the performance of multivariate clustering on many combinations of image texture. Algorithm performance was determined by overlap with ground truth, using multiple overlap measures, and the accuracy of the estimation of the total amount of scar in the LA. Ground truth was determined using the STAPLE algorithm, which produces a probabilistic estimate of the true scar classification from multiple expert manual segmentations. Evaluation of the ground truth data set was based on both inter- and intra-observer agreement, with variation among expert classifiers indicating the difficulty of scar classification for a given a dataset. Our proposed automatic scar classification algorithm performs well for both scar localization and estimation of scar volume: for ground truth datasets considered easy, variability from the ground truth was low; for those considered difficult, variability from ground truth was on par with the variability across experts.

  4. Cerebral blood volume estimation by ferumoxytol-enhanced steady-state MRI at 9.4?T reveals microvascular impact of ?1 -adrenergic receptor antibodies.

    PubMed

    Pohlmann, Andreas; Karczewski, Peter; Ku, Min-Chi; Dieringer, Babette; Waiczies, Helmar; Wisbrun, Natali; Kox, Stefanie; Palatnik, Irina; Reimann, Henning Matthias; Eichhorn, Christina; Waiczies, Sonia; Hempel, Petra; Lemke, Bernd; Niendorf, Thoralf; Bimmler, Marion

    2014-09-01

    Cerebrovascular abnormality is frequently accompanied by cognitive dysfunctions, such as dementia. Antibodies against the ?1 -adrenoceptor (?1 -AR) can be found in patients with Alzheimer's disease with cerebrovascular disease, and have been shown to affect the larger vessels of the brain in rodents. However, the impact of ?1 -AR antibodies on the cerebral vasculature remains unclear. In the present study, we established a neuroimaging method to measure the relative cerebral blood volume (rCBV) in small rodents with the ultimate goal to detect changes in blood vessel density and/or vessel size induced by ?1 -AR antibodies. For this purpose, mapping of R2 * and R2 was performed using MRI at 9.4?T, before and after the injection of intravascular iron oxide particles (ferumoxytol). The change in the transverse relaxation rates (?R2 *, ?R2 ) showed a significant rCBV decrease in the cerebrum, cortex and hippocampus of rats (except hippocampal ?R2 ), which was more pronounced for ?R2 * than for ?R2 . Immunohistological analyses confirmed that the ?1 -AR antibody induced blood vessel deficiencies. Our findings support the hypothesis that ?1 -AR antibodies lead to cerebral vessel damage throughout the brain, which can be monitored by MRI-derived rCBV, a non-invasive neuroimaging method. This demonstrates the value of rCBV estimation by ferumoxytol-enhanced MRI at 9.4?T, and further underlines the significance of this antibody in brain diseases involving vasculature impairments, such as dementia. PMID:25060359

  5. Motion-compensated compressed sensing for dynamic contrast-enhanced MRI using regional spatiotemporal sparsity and region tracking: Block LOw-rank Sparsity with Motion-guidance (BLOSM)

    PubMed Central

    Chen, Xiao; Salerno, Michael; Yang, Yang; Epstein, Frederick H.

    2014-01-01

    Purpose Dynamic contrast-enhanced MRI of the heart is well-suited for acceleration with compressed sensing (CS) due to its spatiotemporal sparsity; however, respiratory motion can degrade sparsity and lead to image artifacts. We sought to develop a motion-compensated CS method for this application. Methods A new method, Block LOw-rank Sparsity with Motion-guidance (BLOSM), was developed to accelerate first-pass cardiac MRI, even in the presence of respiratory motion. This method divides the images into regions, tracks the regions through time, and applies matrix low-rank sparsity to the tracked regions. BLOSM was evaluated using computer simulations and first-pass cardiac datasets from human subjects. Using rate-4 acceleration, BLOSM was compared to other CS methods such as k-t SLR that employs matrix low-rank sparsity applied to the whole image dataset, with and without motion tracking, and to k-t FOCUSS with motion estimation and compensation that employs spatial and temporal-frequency sparsity. Results BLOSM was qualitatively shown to reduce respiratory artifact compared to other methods. Quantitatively, using root mean squared error and the structural similarity index, BLOSM was superior to other methods. Conclusion BLOSM, which exploits regional low rank structure and uses region tracking for motion compensation, provides improved image quality for CS-accelerated first-pass cardiac MRI. PMID:24243528

  6. Intra-Tumor Distribution and Test-Retest Comparisons of Physiological Parameters quantified by Dynamic Contrast-Enhanced MRI in Rat U251 Glioma

    PubMed Central

    Aryal, Madhava P.; Nagaraja, Tavarekere N.; Brown, Stephen L.; Lu, Mei; Bagher-Ebadian, Hassan; Ding, Guangliang; Panda, Swayamprava; Keenan, Kelly; Cabral, Glauber; Mikkelsen, Tom; Ewing, James R.

    2014-01-01

    The distribution of dynamic contrast enhanced MRI (DCE-MRI) parametric estimates in a rat U251 glioma model was analyzed. Using Magnevist as contrast agent (CA), 17 nude rats implanted with U251 cerebral glioma were studied by DCE-MRI twice in a 24 h interval. A data-driven analysis selected one of three models to estimate either: 1) CA plasma volume (vp), 2) vp and forward volume transfer constant (Ktrans; or 3) vp, Ktrans, and interstitial volume fraction (ve), constituting Models 1, 2 and 3, respectively. CA interstitial distribution volume (VD) was estimated in Model 3 regions by Logan plots. Regions of interest (ROIs) were selected by model. In the Model 3 ROI, descriptors of parameter distributions mean, median, variance and skewness were calculated and compared between the two time points for repeatability. All distributions of parametric estimates in Model 3 ROIs were positively skewed. Test-retest differences between population summaries for any parameter were not significant (p?0.10; Wilcoxon signed-rank and paired t tests). This and similar measures of parametric distribution and test-retest variance from other tumor models can be used to inform the choice of biomarkers that best summarize tumor status and treatment effects. PMID:25125367

  7. An investigation into the effects of temporal resolution on hepatic dynamic contrast-enhanced MRI in volunteers and in patients with hepatocellular carcinoma.

    PubMed

    Gill, Andrew B; Black, Richard T; Bowden, David J; Priest, Andrew N; Graves, Martin J; Lomas, David J

    2014-06-21

    This study investigated the effect of temporal resolution on the dual-input pharmacokinetic (PK) modelling of dynamic contrast-enhanced MRI (DCE-MRI) data from normal volunteer livers and from patients with hepatocellular carcinoma. Eleven volunteers and five patients were examined at 3 T. Two sections, one optimized for the vascular input functions (VIF) and one for the tissue, were imaged within a single heart-beat (HB) using a saturation-recovery fast gradient echo sequence. The data was analysed using a dual-input single-compartment PK model. The VIFs and/or uptake curves were then temporally sub-sampled (at interval ?t = [2-20] s) before being subject to the same PK analysis. Statistical comparisons of tumour and normal tissue PK parameter values using a 5% significance level gave rise to the same study results when temporally sub-sampling the VIFs to HB < ?t <4s. However, sub-sampling to ?t > 4s did adversely affect the statistical comparisons. Temporal sub-sampling of just the liver/tumour tissue uptake curves at ?t ? 20s, whilst using high temporal resolution VIFs, did not substantially affect PK parameter statistical comparisons. In conclusion, there is no practical advantage to be gained from acquiring very high temporal resolution hepatic DCE-MRI data. Instead the high temporal resolution could be usefully traded for increased spatial resolution or SNR. PMID:24862216

  8. Reconstructed anterior cruciate ligaments using patellar tendon ligament grafts: diagnostic value of contrast-enhanced MRI in a 2-year follow-up regimen.

    PubMed

    Vogl, T J; Schmitt, J; Lubrich, J; Hochmuth, K; Diebold, T; Del Tredici, K; Sdkamp, N

    2001-01-01

    We analyzed prospectively the diagnostic efficacy of contrast-enhanced MRI following anterior cruciate neoligament (ACL) reconstruction. One hundred fifty-six MR examinations were performed 2, 12, 52, 76, and 104 weeks post-operatively on 68 patients with ACL transplants. Sagittal, parasagittal, and coronal images using unenhanced T1- and T2-weighted spinecho sequences, and post-contrast images utilizing T1-weighted spinecho and fat-saturated sequences, were acquired. Results were correlated with those of the pivot shift, Lachman, and a mechanical test. The MR examination criteria included morphological analysis, signal intensity, transplant contrast enhancement, secondary signs (e.g., elongation of normal ligaments), and comparison with clinically standardized test results. Two weeks post-operatively all neoligaments showed homogeneous low signal intensity on T1- and T2-weighted spinecho sequences indistinguishable from that of normal cruciate or patellar ligaments [contrast-to-noise ratio (C/N) on T1: 1.6], with a 9% percentile enhancement. At 12-52 weeks, signal intensity increased (C/N: 6.7), with a mean 50% percentile enhancement. The 1-year follow-up allowed no definite assessment of the neoligament's course. At 76 and 104 weeks, significant decrements in signal intensity (C/N: 3.0) and ligamentous percentile enhancement (25%) occurred. All patients tested displayed stable transplants 2 years post-operatively. Contrast-enhanced MRI allows accurate evaluation of morphology and function up to 3 months postoperatively and 1-2 years following ACL reconstructive surgery. PMID:11519557

  9. MRI of optic neuritis in a rat model.

    PubMed

    Boretius, Susann; Gadjanski, Ivana; Demmer, Iris; Bhr, Mathias; Diem, Ricarda; Michaelis, Thomas; Frahm, Jens

    2008-06-01

    Neuritis of the optic nerve is one of the most frequent early symptoms of multiple sclerosis. There are only scarce data correlating magnetic resonance imaging (MRI) contrast alterations with the underlying pathology, that is inflammation, demyelination, and axonal damage. Here we studied optic neuritis in a rat model of experimental autoimmune encephalomyelitis by comparing in vivo MRI findings from multiple techniques (T1, T2, proton density, magnetization transfer) to histopathology. We further assessed a breakdown of the blood-brain barrier by using Gd-DTPA and indirectly estimated the intracellular accumulation of calcium as a consequence of axonal damage by using manganese-enhanced MRI. Hyperintensity on T2-weighted images and signal enhancement after Gd-DTPA were highly sensitive to lesions of the optic nerve but did not differentiate between mild, moderate, and severe damage. Signal reduction on T1-weighted images was less sensitive but correlated well with the severity of tissue damage. No significant changes in magnetization transfer ratio were observed. Manganese ions tended to accumulate in the central parts of the inflamed optic nerve. The resulting signal enhancement at 24 h after administration positively correlated with the severity of axonal loss. Thus, manganese might be an indicator of intracellular calcium accumulation that is known to be associated with axon damage. Although none of the methods alone distinguished between inflammation, demyelination, and reduced axon density, their specific capabilities should prove useful for future in vivo MRI studies of optic neuritis in both animal models and humans. PMID:18394926

  10. Alertness in Young Healthy Subjects: An fMRI Study of Brain Region Interactivity Enhanced by a Warning Signal

    ERIC Educational Resources Information Center

    Perin, B.; Godefroy, O.; Fall, S.; de Marco, G.

    2010-01-01

    An effective connectivity study was carried out on 16 young, healthy subjects performing an alertness task. The objective of this study was to develop and to evaluate a putative network model of alertness by adapting structural equation modeling to fMRI data. This study was designed to evaluate the directed interactivity of an attentional network

  11. Integrating diffusion kurtosis imaging, dynamic susceptibility-weighted contrast-enhanced MRI, and short echo time chemical shift imaging for grading gliomas

    PubMed Central

    Van Cauter, Sofie; De Keyzer, Frederik; Sima, Diana M.; Croitor Sava, Anca; D'Arco, Felice; Veraart, Jelle; Peeters, Ronald R.; Leemans, Alexander; Van Gool, Stefaan; Wilms, Guido; Demaerel, Philippe; Van Huffel, Sabine; Sunaert, Stefan; Himmelreich, Uwe

    2014-01-01

    Background We assessed the diagnostic accuracy of diffusion kurtosis imaging (DKI), dynamic susceptibility-weighted contrast-enhanced (DSC) MRI, and short echo time chemical shift imaging (CSI) for grading gliomas. Methods In this prospective study, 35 patients with cerebral gliomas underwent DKI, DSC, and CSI on a 3 T MR scanner. Diffusion parameters were mean diffusivity (MD), fractional anisotropy, and mean kurtosis (MK). Perfusion parameters were mean relative regional cerebral blood volume (rrCBV), mean relative regional cerebral blood flow (rrCBF), mean transit time, and relative decrease ratio (rDR). The diffusion and perfusion parameters along with 12 CSI metabolite ratios were compared among 22 high-grade gliomas and 14 low-grade gliomas (MannWhitney U-test, P < .05). Classification accuracy was determined with a linear discriminant analysis for each MR modality independently. Furthermore, the performance of a multimodal analysis is reported, using a decision-tree rule combining the statistically significant DKI, DSC-MRI, and CSI parameters with the lowest P-value. The proposed classifiers were validated on a set of subsequently acquired data from 19 clinical patients. Results Statistically significant differences among tumor grades were shown for MK, MD, mean rrCBV, mean rrCBF, rDR, lipids over total choline, lipids over creatine, sum of myo-inositol, and sum of creatine. DSC-MRI proved to be the modality with the best performance when comparing modalities individually, while the multimodal decision tree proved to be most accurate in predicting tumor grade, with a performance of 86%. Conclusions Combining information from DKI, DSC-MRI, and CSI increases diagnostic accuracy to differentiate low- from high-grade gliomas, possibly providing diagnosis for the individual patient. PMID:24470551

  12. Water-Exchange-Modified Kinetic Parameters from Dynamic Contrast-Enhanced MRI as Prognostic Biomarkers of Survival in Advanced Hepatocellular Carcinoma Treated with Antiangiogenic Monotherapy

    PubMed Central

    Lee, Sang Ho; Hayano, Koichi; Zhu, Andrew X.; Sahani, Dushyant V.; Yoshida, Hiroyuki

    2015-01-01

    Background To find prognostic biomarkers in pretreatment dynamic contrast-enhanced MRI (DCE-MRI) water-exchange-modified (WX) kinetic parameters for advanced hepatocellular carcinoma (HCC) treated with antiangiogenic monotherapy. Methods Twenty patients with advanced HCC underwent DCE-MRI and were subsequently treated with sunitinib. Pretreatment DCE-MRI data on advanced HCC were analyzed using five different WX kinetic models: the Tofts-Kety (WX-TK), extended TK (WX-ETK), two compartment exchange, adiabatic approximation to tissue homogeneity (WX-AATH), and distributed parameter (WX-DP) models. The total hepatic blood flow, arterial flow fraction (?), arterial blood flow (BFA), portal blood flow, blood volume, mean transit time, permeability-surface area product, fractional interstitial volume (vI), extraction fraction, mean intracellular water molecule lifetime (?C), and fractional intracellular volume (vC) were calculated. After receiver operating characteristic analysis with leave-one-out cross-validation, individual parameters for each model were assessed in terms of 1-year-survival (1YS) discrimination using Kaplan-Meier analysis, and association with overall survival (OS) using univariate Cox regression analysis with permutation testing. Results The WX-TK-model-derived ? (P = 0.022) and vI (P = 0.010), and WX-ETK-model-derived ?C (P = 0.023) and vC (P = 0.042) were statistically significant prognostic biomarkers for 1YS. Increase in the WX-DP-model-derived BFA (P = 0.025) and decrease in the WX-TK, WX-ETK, WX-AATH, and WX-DP-model-derived vC (P = 0.034, P = 0.038, P = 0.028, P = 0.041, respectively) were significantly associated with an increase in OS. Conclusions The WX-ETK-model-derived vC was an effective prognostic biomarker for advanced HCC treated with sunitinib. PMID:26366997

  13. Preoperative dynamic contrast-enhanced MRI correlates with molecular markers of hypoxia and vascularity in specific areas of intratumoral microenvironment and is predictive of patient outcome

    PubMed Central

    Jensen, Randy L.; Mumert, Michael L.; Gillespie, David L.; Kinney, Anita Y.; Schabel, Matthias C.; Salzman, Karen L.

    2014-01-01

    Background Measures of tumor vascularity and hypoxia have been correlated with glioma grade and outcome. Dynamic contrast-enhanced (DCE) MRI can noninvasively map tumor blood flow, vascularity, and permeability. In this prospective observational cohort pilot study, preoperative imaging was correlated with molecular markers of hypoxia, vascularity, proliferation, and progression-free and overall patient survival. Methods Pharmacokinetic modeling methods were used to generate maps of tumor blood flow, extraction fraction, permeability-surface area product, transfer constant, washout rate, interstitial volume, blood volume, capillary transit time, and capillary heterogeneity from preoperative DCE-MRI data in human glioma patients. Tissue was obtained from areas of peritumoral edema, active tumor, hypoxic penumbra, and necrotic core and evaluated for vascularity, proliferation, and expression of hypoxia-regulated molecules. DCE-MRI parameter values were correlated with hypoxia-regulated protein expression at tissue sample sites. Results Patient survival correlated with DCE parameters in 2 cases: capillary heterogeneity in active tumor and interstitial volume in areas of peritumoral edema. Statistically significant correlations were observed between several DCE parameters and tissue markers. In addition, MIB-1 index was predictive of overall survival (P = .044) and correlated with vascular endothelial growth factor expression in hypoxic penumbra (r = 0.7933, P = .0071) and peritumoral edema (r = 0.4546). Increased microvessel density correlated with worse patient outcome (P = .026). Conclusions Our findings suggest that DCE-MRI may facilitate noninvasive preoperative predictions of areas of tumor with increased hypoxia and proliferation. Both imaging and hypoxia biomarkers are predictive of patient outcome. This has the potential to allow unprecedented prognostic decisions and to guide therapies to specific tumor areas. PMID:24305704

  14. Comparison of triple dose versus standard dose gadolinium-DTPA for detection of MRI enhancing lesions in patients with primary progressive multiple sclerosis.

    PubMed Central

    Filippi, M; Campi, A; Martinelli, V; Colombo, B; Yousry, T; Canal, N; Scotti, G; Comi, G

    1995-01-01

    This study was performed to evaluate whether a triple dose of gadolinium-DTPA (Gd-DTPA) increases the sensitivity of brain MRI for detecting enhancing lesions in patients with primary progressive multiple sclerosis (PPMS). T1 weighted brain MRI was obtained for 10 patients with PPMS in two sessions. In the first session, one scan was obtained five to seven minutes after the injection of 0.1 mmol/kg Gd-DTPA (standard dose). In the second session, six to 24 hours later, one scan before and two scans five to seven minutes and one hour after the injection of 0.3 mmol/kg Gd-DTPA (triple dose) were obtained. Four enhancing lesions were detected in two patients when the standard dose of Gd-DTPA was used. The numbers of enhancing lesions increased to 13 and the numbers of patients with such lesions to five when the triple dose of Gd-DTPA was used and to 14 and six in the one hour delayed scans. The mean contrast ratio for enhancing lesions detected with the triple dose of Gd-DTPA was higher than those for lesions present in both the standard dose (P < 0.0009) and the one hour delayed scans (P = 0.04). These data indicate that with a triple dose of Gd-DTPA many more enhancing lesions can be detected in patients with PPMS. This is important both for planning clinical trials and for detecting the presence of inflammation in vivo in the lesions of such patients. Images PMID:8530944

  15. Dynamic Contrast-Enhanced MRI in Head-and-Neck Cancer: The Impact of Region of Interest Selection on the Intra- and Interpatient Variability of Pharmacokinetic Parameters

    SciTech Connect

    Craciunescu, Oana I.; Yoo, David S.; Cleland, Esi; Muradyan, Naira; Carroll, Madeline D.; MacFall, James R.; Barboriak, Daniel P.; Brizel, David M.

    2012-03-01

    Purpose: Dynamic contrast-enhanced (DCE) MRI-extracted parameters measure tumor microvascular physiology and are usually calculated from an intratumor region of interest (ROI). Optimal ROI delineation is not established. The valid clinical use of DCE-MRI requires that the variation for any given parameter measured within a tumor be less than that observed between tumors in different patients. This work evaluates the impact of tumor ROI selection on the assessment of intra- and interpatient variability. Method and Materials: Head and neck cancer patients received initial targeted therapy (TT) treatment with erlotinib and/or bevacizumab, followed by radiotherapy and concurrent cisplatin with synchronous TT. DCE-MRI data from Baseline and the end of the TT regimen (Lead-In) were analyzed to generate the vascular transfer function (K{sup trans}), the extracellular volume fraction (v{sub e}), and the initial area under the concentration time curve (iAUC{sub 1min}). Four ROI sampling strategies were used: whole tumor or lymph node (Whole), the slice containing the most enhancing voxels (SliceMax), three slices centered in SliceMax (Partial), and the 5% most enhancing contiguous voxels within SliceMax (95Max). The average coefficient of variation (aCV) was calculated to establish intrapatient variability among ROI sets and interpatient variability for each ROI type. The average ratio between each intrapatient CV and the interpatient CV was calculated (aRCV). Results: Baseline primary/nodes aRCVs for different ROIs not including 95Max were, for all three MR parameters, in the range of 0.14-0.24, with Lead-In values between 0.09 and 0.2, meaning a low intrapatient vs. interpatient variation. For 95Max, intrapatient CVs approximated interpatient CVs, meaning similar data dispersion and higher aRCVs (0.6-1.27 for baseline) and 0.54-0.95 for Lead-In. Conclusion: Distinction between different patient's primary tumors and/or nodes cannot be made using 95Max ROIs. The other three strategies are viable and equivalent for using DCE-MRI to measure head and neck cancer physiology.

  16. Enhanced cellular uptake and long-term retention of chitosan-modified iron-oxide nanoparticles for MRI-based cell tracking

    PubMed Central

    Bakhru, Sasha H; Altiok, Eda; Highley, Christopher; Delubac, Daniel; Suhan, Joseph; Hitchens, T Kevin; Ho, Chien; Zappe, Stefan

    2012-01-01

    Tracking cells after therapeutic transplantation is imperative for evaluation of implanted cell fate and function. In this study, ultrasmall superparamagnetic iron oxide nanoparticles (USPIO NPs) were surface functionalized with water-soluble chitosan, a cationic polysaccharide that mediates enhanced endocytic uptake, endosomal escape into the cytosol, and subsequent long-term retention of nanoparticles. NP surface and chitosan were independently fluorescently labeled. Our NPs enable NP trafficking studies and determination of fate beyond uptake by fluorescence microscopy as well as tracking of labeled cells as localized regions of hypointensity in T2*-weighted magnetic resonance imaging (MRI) images. Adult rat neural stem cells (NSCs) were labeled with NPs, and assessment of NSC proliferation rates and differentiation potential revealed no significant differences between labeled and unlabeled NSCs. Significantly enhanced uptake of chitosan NPs in comparison to native NPs was confirmed by transmission electron microscopy, nuclear magnetic resonance (NMR) spectroscopy and in vitro cellular MRI at 11.7 Tesla. While only negligible fractions of native NPs enter cells, chitosan NPs appear within membranous vesicles within 2 hours of exposure. Additionally, chitosan-functionalized NPs escaped from membrane-bound vesicles within days, circumventing NP endo-lysosomal trafficking and exocytosis and hence enabling long-term tracking of labeled cells. Finally, our labeling strategy does not contain any NSC-specific reagents. To demonstrate general applicability across a variety of primary and immortalized cell types, embryonic mouse NSCs, mouse embryonic stem cells, HEK 293 kidney cells, and HeLa cervical cancer cells were additionally exposed to chitosan-USPIO NPs and exhibited similarly efficient loading as verified by NMR relaxometry. Our efficient and versatile labeling technology can support cell tracking with close to single cell resolution by MRI in vitro, for example, in complex tissue models not optically accessible by confocal or multi-photon fluorescence microscopy, and potentially in vivo, for example, in animal models of human disease or injury. PMID:22942643

  17. Distinguishing modified gravity models

    NASA Astrophysics Data System (ADS)

    Brax, Philippe; Davis, Anne-Christine

    2015-10-01

    Modified gravity models with screening in local environments appear in three different guises: chameleon, K-mouflage and Vainshtein mechanisms. We propose to look for differences between these classes of models by considering cosmological observations at low redshift. In particular, we analyse the redshift dependence of the fine structure constant and the proton to electron mass ratio in each of these scenarios. When the absorption lines belong to unscreened regions of space such as dwarf galaxies, a time variation would be present for chameleons. For both K-mouflage and Vainshtein mechanisms, the cosmological time variation of the scalar field is not suppressed in both unscreened and screened environments, therefore enhancing the variation of constants and their detection prospect. We also consider the time variation of the redshift of distant objects using their spectrocopic velocities. We find that models of the K-mouflage and Vainshtein types have very different spectroscopic velocities as a function of redshift and that their differences with the ?-CDM template should be within reach of the future ELT-HIRES observations.

  18. Decision tree analysis as a supplementary tool to enhance histomorphological differentiation when distinguishing human from non-human cranial bone in both burnt and unburnt states: A feasibility study.

    PubMed

    Simmons, T; Goodburn, B; Singhrao, S K

    2016-01-01

    This feasibility study was undertaken to describe and record the histological characteristics of burnt and unburnt cranial bone fragments from human and non-human bones. Reference series of fully mineralized, transverse sections of cranial bone, from all variables and specimen states, were prepared by manual cutting and semi-automated grinding and polishing methods. A photomicrograph catalogue reflecting differences in burnt and unburnt bone from human and non-humans was recorded and qualitative analysis was performed using an established classification system based on primary bone characteristics. The histomorphology associated with human and non-human samples was, for the main part, preserved following burning at high temperature. Clearly, fibro-lamellar complex tissue subtypes, such as plexiform or laminar primary bone, were only present in non-human bones. A decision tree analysis based on histological features provided a definitive identification key for distinguishing human from non-human bone, with an accuracy of 100%. The decision tree for samples where burning was unknown was 96% accurate, and multi-step classification to taxon was possible with 100% accuracy. The results of this feasibility study strongly suggest that histology remains a viable alternative technique if fragments of cranial bone require forensic examination in both burnt and unburnt states. The decision tree analysis may provide an additional but vital tool to enhance data interpretation. Further studies are needed to assess variation in histomorphology taking into account other cranial bones, ontogeny, species and burning conditions. PMID:26130749

  19. A facile synthesis of versatile Cu2-xS nanoprobe for enhanced MRI and infrared thermal/photoacoustic multimodal imaging.

    PubMed

    Mou, Juan; Liu, Chengbo; Li, Pei; Chen, Yu; Xu, Huixiong; Wei, Chenyang; Song, Liang; Shi, Jianlin; Chen, Hangrong

    2015-07-01

    A novel type of intelligent nanoprobe by using single component of Cu2-xS for multimodal imaging has been facilely and rapidly synthesized in scale via thermal decomposition followed by biomimetic phospholipid modification, which endows them with uniform and small nanoparticle size (ca.15 nm), well phosphate buffer saline (PBS) dispersity, high stability, and excellent biocompatibility. The as-synthesized Cu2-xS nanoprobes (Cu2-xS NPs) are capable of providing contrast enhancement for T1-weighted magnetic resonance imaging (MRI), as demonstrated by the both in vitro and in vivo imaging investigations for the first time. In addition, due to their strong near infrared (NIR) optical absorption, they can also serve as a candidate contrast agent for enhanced infrared thermal/photoacoustic imaging, to meet the shortfalls of MRI. Hence, complementary and potentially more comprehensive information can be acquired for the early detection and accurate diagnosis of cancer. Furthermore, negligible systematic side effects to the blood and tissue were observed in a relatively long period of 3 months. The distinctive multimodal imaging capability with excellent hemo/histocompatibility of the Cu2-xS NPs could open up a new molecular imaging possibility for detecting and diagnosing cancer or other diseases in the future. PMID:25956193

  20. Accurate High-Resolution Measurements of 3-D Tissue Dynamics With Registration-Enhanced Displacement Encoded MRI

    PubMed Central

    Merchant, Samer S.; Hsu, Edward W.

    2014-01-01

    Displacement fields are important to analyze deformation, which is associated with functional and material tissue properties often used as indicators of health. Magnetic resonance imaging (MRI) techniques like DENSE and image registration methods like Hyperelastic Warping have been used to produce pixel-level deformation fields that are desirable in high-resolution analysis. However, DENSE can be complicated by challenges associated with image phase unwrapping, in particular offset determination. On the other hand, Hyperelastic Warping can be hampered by low local image contrast. The current work proposes a novel approach for measuring tissue displacement with both DENSE and Hyperelastic Warping, incorporating physically accurate displacements obtained by the latter to improve phase characterization in DENSE. The validity of the proposed technique is demonstrated using numerical and physical phantoms, and in vivo small animal cardiac MRI. PMID:24771572

  1. MRI Scans

    MedlinePLUS

    Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. Health care professionals use MRI scans to diagnose a variety of conditions, from torn ...

  2. MO-G-BRF-02: Enhancement of Texture-Based Metastasis Prediction Models Via the Optimization of PET/MRI Acquisition Protocols

    SciTech Connect

    Vallieres, M; Laberge, S; Levesque I, R; El Naqa, I

    2014-06-15

    Purpose: We have previously identified a prediction model of lung metastases at diagnosis of soft-tissue sarcomas (STS) that is composed of two textural features extracted from FDG-PET and T1-weighted (T1w) MRI scans. The goal of this study is to evaluate whether the optimization in FDGPET and MRI acquisition parameters would enhance the prediction performance of texture-based models. Methods: Ten FDG-PET and T1w- MRI digitized tumor models were generated from imaging data of STS patients who underwent pre-treatment clinical scans between 2005 and 2011. Five of ten patients eventually developed lung metastases. Numerically simulated MR images were produced using echo times (TE) of 2 and 4 times the nominal clinical parameter (TEc), and repetition times (TR) of 0.5, 0.67, 1.5 and 2 times the nominal clinical parameter (TRc) found in the DICOM headers (TEc range: 9–13 ms, TRc range: 410-667 ms). PET 2D images were simulated using Monte-Carlo and were reconstructed using an ordered-subsets expectation maximization (OSEM) algorithm with 1 to 32 iterations and a post-reconstruction Gaussian filter of 0, 2, 4 or 6 mm width. For all possible combinations of PET and MRI acquisition parameters, the prediction model was constructed using logistic regression with new coefficients, and its associated prediction performance for lung metastases was evaluated using the area under the ROC curve (AUC). Results: The prediction performance over all simulations yielded AUCs ranging from 0.7 to 1. Notably, TR values below or equal to TRc and higher PET post-reconstruction filter widths yielded higher prediction performance. The best results were obtained with a combination of 4*TEc, TRc, 30 OSEM iterations and 2mm filter width. Conclusion: This work indicates that texture-based metastasis prediction models could be improved using optimized choices of FDG-PET and MRI acquisition protocols. This principle could be generalized to other texture-based models.

  3. Distinguishing drought and water scarcity

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2013-04-01

    Water resources can become strained by both natural factors such as drought and human factors such as unsustainable use. Water resource managers can develop practices to reduce overuse of water resources, but they cannot prevent droughts, so distinguishing the causes of water stress can be useful. However, because the two factors often occur at the same time, distinguishing between them can be difficult.

  4. Enhanced Multi-Protocol Analysis via Intelligent Supervised Embedding (EMPrAvISE): Detecting Prostate Cancer on Multi-Parametric MRI

    PubMed Central

    Viswanath, Satish; Bloch, B. Nicolas; Chappelow, Jonathan; Patel, Pratik; Rofsky, Neil; Lenkinski, Robert; Genega, Elisabeth; Madabhushi, Anant

    2014-01-01

    Currently, there is significant interest in developing methods for quantitative integration of multi-parametric (structural, functional) imaging data with the objective of building automated meta-classifiers to improve disease detection, diagnosis, and prognosis. Such techniques are required to address the differences in dimensionalities and scales of individual protocols, while deriving an integrated multi-parametric data representation which best captures all disease-pertinent information available. In this paper, we present a scheme called Enhanced Multi-Protocol Analysis via Intelligent Supervised Embedding (EMPrAvISE); a powerful, generalizable framework applicable to a variety of domains for multi-parametric data representation and fusion. Our scheme utilizes an ensemble of embeddings (via dimensionality reduction, DR); thereby exploiting the variance amongst multiple uncorrelated embeddings in a manner similar to ensemble classifier schemes (e.g. Bagging, Boosting). We apply this framework to the problem of prostate cancer (CaP) detection on 12 3 Tesla pre-operative in vivo multi-parametric (T2-weighted, Dynamic Contrast Enhanced, and Diffusion-weighted) magnetic resonance imaging (MRI) studies, in turn comprising a total of 39 2D planar MR images. We first align the different imaging protocols via automated image registration, followed by quantification of image attributes from individual protocols. Multiple embeddings are generated from the resultant high-dimensional feature space which are then combined intelligently to yield a single stable solution. Our scheme is employed in conjunction with graph embedding (for DR) and probabilistic boosting trees (PBTs) to detect CaP on multi-parametric MRI. Finally, a probabilistic pairwise Markov Random Field algorithm is used to apply spatial constraints to the result of the PBT classifier, yielding a per-voxel classification of CaP presence. Per-voxel evaluation of detection results against ground truth for CaP extent on MRI (obtained by spatially registering pre-operative MRI with available whole-mount histological specimens) reveals that EMPrAvISE yields a statistically significant improvement (AUC=0.77) over classifiers constructed from individual protocols (AUC=0.62, 0.62, 0.65, for T2w, DCE, DWI respectively) as well as one trained using multi-parametric feature concatenation (AUC=0.67). PMID:25301991

  5. Enhanced multi-protocol analysis via intelligent supervised embedding (EMPrAvISE): detecting prostate cancer on multi-parametric MRI

    NASA Astrophysics Data System (ADS)

    Viswanath, Satish; Bloch, B. Nicholas; Chappelow, Jonathan; Patel, Pratik; Rofsky, Neil; Lenkinski, Robert; Genega, Elizabeth; Madabhushi, Anant

    2011-03-01

    Currently, there is significant interest in developing methods for quantitative integration of multi-parametric (structural, functional) imaging data with the objective of building automated meta-classifiers to improve disease detection, diagnosis, and prognosis. Such techniques are required to address the differences in dimensionalities and scales of individual protocols, while deriving an integrated multi-parametric data representation which best captures all disease-pertinent information available. In this paper, we present a scheme called Enhanced Multi-Protocol Analysis via Intelligent Supervised Embedding (EMPrAvISE); a powerful, generalizable framework applicable to a variety of domains for multi-parametric data representation and fusion. Our scheme utilizes an ensemble of embeddings (via dimensionality reduction, DR); thereby exploiting the variance amongst multiple uncorrelated embeddings in a manner similar to ensemble classifier schemes (e.g. Bagging, Boosting). We apply this framework to the problem of prostate cancer (CaP) detection on 12 3 Tesla pre-operative in vivo multi-parametric (T2-weighted, Dynamic Contrast Enhanced, and Diffusion-weighted) magnetic resonance imaging (MRI) studies, in turn comprising a total of 39 2D planar MR images. We first align the different imaging protocols via automated image registration, followed by quantification of image attributes from individual protocols. Multiple embeddings are generated from the resultant high-dimensional feature space which are then combined intelligently to yield a single stable solution. Our scheme is employed in conjunction with graph embedding (for DR) and probabilistic boosting trees (PBTs) to detect CaP on multi-parametric MRI. Finally, a probabilistic pairwise Markov Random Field algorithm is used to apply spatial constraints to the result of the PBT classifier, yielding a per-voxel classification of CaP presence. Per-voxel evaluation of detection results against ground truth for CaP extent on MRI (obtained by spatially registering pre-operative MRI with available whole-mount histological specimens) reveals that EMPrAvISE yields a statistically significant improvement (AUC=0.77) over classifiers constructed from individual protocols (AUC=0.62, 0.62, 0.65, for T2w, DCE, DWI respectively) as well as one trained using multi-parametric feature concatenation (AUC=0.67).

  6. Enhanced Multi-Protocol Analysis via Intelligent Supervised Embedding (EMPrAvISE): Detecting Prostate Cancer on Multi-Parametric MRI.

    PubMed

    Viswanath, Satish; Bloch, B Nicolas; Chappelow, Jonathan; Patel, Pratik; Rofsky, Neil; Lenkinski, Robert; Genega, Elisabeth; Madabhushi, Anant

    2011-03-01

    Currently, there is significant interest in developing methods for quantitative integration of multi-parametric (structural, functional) imaging data with the objective of building automated meta-classifiers to improve disease detection, diagnosis, and prognosis. Such techniques are required to address the differences in dimensionalities and scales of individual protocols, while deriving an integrated multi-parametric data representation which best captures all disease-pertinent information available. In this paper, we present a scheme called Enhanced Multi-Protocol Analysis via Intelligent Supervised Embedding (EMPrAvISE); a powerful, generalizable framework applicable to a variety of domains for multi-parametric data representation and fusion. Our scheme utilizes an ensemble of embeddings (via dimensionality reduction, DR); thereby exploiting the variance amongst multiple uncorrelated embeddings in a manner similar to ensemble classifier schemes (e.g. Bagging, Boosting). We apply this framework to the problem of prostate cancer (CaP) detection on 12 3 Tesla pre-operative in vivo multi-parametric (T2-weighted, Dynamic Contrast Enhanced, and Diffusion-weighted) magnetic resonance imaging (MRI) studies, in turn comprising a total of 39 2D planar MR images. We first align the different imaging protocols via automated image registration, followed by quantification of image attributes from individual protocols. Multiple embeddings are generated from the resultant high-dimensional feature space which are then combined intelligently to yield a single stable solution. Our scheme is employed in conjunction with graph embedding (for DR) and probabilistic boosting trees (PBTs) to detect CaP on multi-parametric MRI. Finally, a probabilistic pairwise Markov Random Field algorithm is used to apply spatial constraints to the result of the PBT classifier, yielding a per-voxel classification of CaP presence. Per-voxel evaluation of detection results against ground truth for CaP extent on MRI (obtained by spatially registering pre-operative MRI with available whole-mount histological specimens) reveals that EMPrAvISE yields a statistically significant improvement (AUC=0.77) over classifiers constructed from individual protocols (AUC=0.62, 0.62, 0.65, for T2w, DCE, DWI respectively) as well as one trained using multi-parametric feature concatenation (AUC=0.67). PMID:25301991

  7. Enhancement of Temporal Resolution and BOLD Sensitivity in Real-Time fMRI using Multi-Slab Echo-Volumar Imaging

    PubMed Central

    Posse, Stefan; Ackley, Elena; Mutihac, Radu; Rick, Jochen; Shane, Matthew; Murray-Krezan, Cristina; Zaitsev, Maxim; Speck, Oliver

    2012-01-01

    In this study, a new approach to high-speed fMRI using multi-slab echo-volumar imaging (EVI) is developed that minimizes geometrical image distortion and spatial blurring, and enables nonaliased sampling of physiological signal fluctuation to increase BOLD sensitivity compared to conventional echo-planar imaging (EPI). Real-time fMRI using whole brain 4-slab EVI with 286 ms temporal resolution (4 mm isotropic voxel size) and partial brain 2-slab EVI with 136 ms temporal resolution (446 mm3 voxel size) was performed on a clinical 3 Tesla MRI scanner equipped with 12-channel head coil. Four-slab EVI of visual and motor tasks significantly increased mean (visual: 96%, motor: 66%) and maximum t-score (visual: 263%, motor: 124%) and mean (visual: 59%, motor: 131%) and maximum (visual: 29%, motor: 67%) BOLD signal amplitude compared with EPI. Time domain moving average filtering (2 s width) to suppress physiological noise from cardiac and respiratory fluctuations further improved mean (visual: 196%, motor: 140%) and maximum (visual: 384%, motor: 200%) t-scores and increased extents of activation (visual: 73%, motor: 70%) compared to EPI. Similar sensitivity enhancement, which is attributed to high sampling rate at only moderately reduced temporal signal-to-noise ratio (mean: ? 52%) and longer sampling of the BOLD effect in the echo-time domain compared to EPI, was measured in auditory cortex. Two-slab EVI further improved temporal resolution for measuring task-related activation and enabled mapping of five major resting state networks (RSNs) in individual subjects in 5 min scans. The bilateral sensorimotor, the default mode and the occipital RSNs were detectable in time frames as short as 75 s. In conclusion, the high sampling rate of real-time multi-slab EVI significantly improves sensitivity for studying the temporal dynamics of hemodynamic responses and for characterizing functional networks at high field strength in short measurement times. PMID:22398395

  8. Vascular biomarkers derived from dynamic contrast-enhanced MRI predict response of vestibular schwannoma to antiangiogenic therapy in type 2 neurofibromatosis

    PubMed Central

    Li, Ka-Loh; Djoukhadar, Ibrahim; Zhu, Xiaoping; Zhao, Sha; Lloyd, Simon; McCabe, Martin; McBain, Catherine; Evans, D. Gareth; Jackson, Alan

    2016-01-01

    Background Antiangiogenic therapy of vestibular schwannoma (VS) in type 2 neurofibromatosis can produce tumor shrinkage with response rates of 40%60%. This study examines the predictive value of parameter-derived MRI in this setting. Methods Twelve patients with 20 VSs were recruited. Each had at least one rapidly growing tumor. Patients were treated with bevacizumab, 5 mg/kg every 2 weeks. Patients with stable or reduced VS volume were maintained at 2.55 mg every 4 weeks after 6 months. Those who failed treatment had their bevacizumab discontinued. Dynamic contrast-enhanced (DCE) MRI performed prior to treatment using a high temporal resolution technique, and data were analyzed to allow measurement of contrast transfer coefficient (Ktrans), vascular fraction (vp), extravascular-extracellular fraction (ve). Relaxation rate (R1N) was measured using a variable flip angle technique. Apparent diffusional coefficient (ADC) was calculated from diffusion-weighted imaging. The predictive power of microvascular parameters and ADC were examined using logistic regression modeling. Results Responding tumors were larger (P < .001), had lower R1N (P < .001), and higher Ktrans (P < .05) and ADC (P < .01). They showed increases in R1N (P < .01) and reduction of Ktrans (P < .01) and ADC (P < .01). Modeling to predict response demonstrated significant independent predictive power for R1N (? = ? 0.327, P < .001), and Ktrans (? = 0.156, P < .05). Modeling to predict percentage change in tumor volume at 90 days identified baseline tumor volume (? = 5.503, P < .05), R1N (? = ? 5.844, P < .05), and Ktrans (? = 5.622, P < .05) as independent significant predictors. Conclusions In patients with type 2 neurofibromatosis, biomarkers from DCE-MRI are predictive of VS volume response to inhibition of vascular endothelial growth factor inhibition. PMID:26311690

  9. Dynamic contrast-enhanced MRI texture analysis for pretreatment prediction of clinical and pathological response to neoadjuvant chemotherapy in patients with locally advanced breast cancer.

    PubMed

    Teruel, Jose R; Heldahl, Mariann G; Goa, Pl E; Pickles, Martin; Lundgren, Steinar; Bathen, Tone F; Gibbs, Peter

    2014-08-01

    The aim of this study was to investigate the potential of texture analysis, applied to dynamic contrast-enhanced MRI (DCE-MRI), to predict the clinical and pathological response to neoadjuvant chemotherapy (NAC) in patients with locally advanced breast cancer (LABC) before NAC is started. Fifty-eight patients with LABC were classified on the basis of their clinical response according to the Response Evaluation Criteria in Solid Tumors (RECIST) guidelines after four cycles of NAC, and according to their pathological response after surgery. T1 -weighted DCE-MRI with a temporal resolution of 1?min was acquired on a 3-T Siemens Trio scanner using a dedicated four-channel breast coil before the onset of treatment. Each lesion was segmented semi-automatically using the 2-min post-contrast subtracted image. Sixteen texture features were obtained at each non-subtracted post-contrast time point using a gray level co-occurrence matrix. Appropriate statistical analyses were performed and false discovery rate-based q values were reported to correct for multiple comparisons. Statistically significant results were found at 1-3?min post-contrast for various texture features for the prediction of both the clinical and pathological response. In particular, eight texture features were found to be statistically significant at 2?min post-contrast, the most significant feature yielding an area under the curve (AUC) of 0.77 for response prediction for stable disease versus complete responders after four cycles of NAC. In addition, four texture features were found to be significant at the same time point, with an AUC of 0.69 for response prediction using the most significant feature for classification based on the pathological response. Our results suggest that texture analysis could provide clinicians with additional information to increase the accuracy of prediction of an individual response before NAC is started. PMID:24840393

  10. Enhancement of Odor-Induced Activity in the Canine Brain by Zinc Nanoparticles: A Functional MRI Study in Fully Unrestrained Conscious Dogs.

    PubMed

    Jia, Hao; Pustovyy, Oleg M; Wang, Yun; Waggoner, Paul; Beyers, Ronald J; Schumacher, John; Wildey, Chester; Morrison, Edward; Salibi, Nouha; Denney, Thomas S; Vodyanoy, Vitaly J; Deshpande, Gopikrishna

    2016-01-01

    Using noninvasive in vivo functional magnetic resonance imaging (fMRI), we demonstrate that the enhancement of odorant response of olfactory receptor neurons by zinc nanoparticles leads to increase in activity in olfaction-related and higher order areas of the dog brain. To study conscious dogs, we employed behavioral training and optical motion tracking for reducing head motion artifacts. We obtained brain activation maps from dogs in both anesthetized state and fully conscious and unrestrained state. The enhancement effect of zinc nanoparticles was higher in conscious dogs with more activation in higher order areas as compared with anesthetized dogs. In conscious dogs, voxels in the olfactory bulb and hippocampus showed higher activity to odorants mixed with zinc nanoparticles as compared with pure odorants, odorants mixed with gold nanoparticles as well as zinc nanoparticles alone. These regions have been implicated in odor intensity processing in other species including humans. If the enhancement effect of zinc nanoparticles observed in vivo are confirmed by future behavioral studies, zinc nanoparticles may provide a way for enhancing the olfactory sensitivity of canines for detection of target substances such as explosives and contraband substances at very low concentrations, which would otherwise go undetected. PMID:26464498

  11. Resting-state fMRI reveals enhanced functional connectivity in spatial navigation networks after transcranial direct current stimulation.

    PubMed

    Krishnamurthy, Venkatagiri; Gopinath, Kaundinya; Brown, Gregory S; Hampstead, Benjamin M

    2015-09-14

    A number of studies have established that transcranial direct current stimulation (tDCS) modulates cortical excitability. We previously demonstrated polarity dependent changes in parietal lobe blood oxygen level dependent (BOLD) fMRI in a group of young adults during a spatial navigation task [15]. Here we used resting state functional connectivity (rsFC) to examine whether analogous changes were also evident during the resting state. Participants were randomized to either a parietal-anodal, frontal-cathodal (P+F-) or the opposite montage (P-F+) and received 20min of tDCS (2mA) before undergoing resting-state fMRI. rsFC was evaluated between the groups by placing a seed in the medial superior parietal lobule (mSPL), which was under the target electrode. rsFC between the mSPL and a number of other areas involved in spatial navigation, scene processing, and sensorimotor processing was significantly higher in the P+F- than the P-F+ group. Thus, the modulatory effects of tDCS were evident during rest and suggest that stimulation primes not just the underlying neocortex but an extended network that can be recruited as necessary during active task performance. PMID:26240994

  12. Evidence of key tinnitus-related brain regions documented by a unique combination of manganese-enhanced MRI and acoustic startle reflex testing.

    PubMed

    Holt, Avril Genene; Bissig, David; Mirza, Najab; Rajah, Gary; Berkowitz, Bruce

    2010-01-01

    Animal models continue to improve our understanding of tinnitus pathogenesis and aid in development of new treatments. However, there are no diagnostic biomarkers for tinnitus-related pathophysiology for use in awake, freely moving animals. To address this disparity, two complementary methods were combined to examine reliable tinnitus models (rats repeatedly administered salicylate or exposed to a single noise event): inhibition of acoustic startle and manganese-enhanced MRI. Salicylate-induced tinnitus resulted in wide spread supernormal manganese uptake compared to noise-induced tinnitus. Neither model demonstrated significant differences in the auditory cortex. Only in the dorsal cortex of the inferior colliculus (DCIC) did both models exhibit supernormal uptake. Therefore, abnormal membrane depolarization in the DCIC appears to be important in tinnitus-mediated activity. Our results provide the foundation for future studies correlating the severity and longevity of tinnitus with hearing loss and neuronal activity in specific brain regions and tools for evaluating treatment efficacy across paradigms. PMID:21179508

  13. Quantitative in vivo measurement of early axonal transport deficits in a triple transgenic mouse model of Alzheimers disease using manganese-enhanced MRI

    PubMed Central

    Kim, Jieun; Choi, In-Young; Michaelis, Mary L.; Lee, Phil

    2011-01-01

    Impaired axonal transport has been linked to the pathogenic processes of Alzheimers disease (AD) in which axonal swelling and degeneration are prevalent. The development of non-invasive neuroimaging methods to quantitatively assess in vivo axonal transport deficits would be enormously valuable to visualize early, yet subtle, changes in the AD brain, to monitor the disease progression and to quantify the effect of drug intervention. A triple transgenic mouse model of AD closely resembles human AD neuropathology. In this study, we investigated age-dependent alterations in the axonal transport rate in a longitudinal assessment of the triple transgenic mouse olfactory system, using fast multi-sliced T1 mapping with manganese-enhanced MRI. The data show that impairment in axonal transport is a very early event in AD pathology in these mice, preceding both deposition of A? plaques and formation of Tau fibrils. PMID:21338698

  14. Validation of 10-Minute Delayed Hepatocyte Phase Imaging with 30 Flip Angle in Gadoxetic Acid-Enhanced MRI for the Detection of Liver Metastasis

    PubMed Central

    Lee, Dahye; Cho, Eun-Suk; Kim, Dae Jung; Kim, Joo Hee; Yu, Jeong-Sik; Chung, Jae-Joon

    2015-01-01

    Objectives To compare 10-minute delayed hepatocyte phase imaging using a 30 flip angle (10min-FA30) and 20-minute hepatocyte phase imaging using a 10 FA (20min-FA10) in gadoxetic acid-enhanced MRI of patients with possible liver metastases, regarding lesion-to-liver contrast-to-noise ratio (CNR) and focal hepatic lesion (FHL) detection to evaluate whether 10min-FA30 would be superior to 20min-FA10. Materials and Methods Eighty-three patients with 248 liver metastases and 78 benign FHLs who underwent gadoxetic acid-enhanced MRI with 10min-FA30 and 20min-FA10 were enrolled. Lesion-to-liver CNRs were compared between the two image groups. Two radiologists independently assessed the presence of FHLs using a four-point scale and detection sensitivity was calculated. Results The mean CNR for liver metastases on the 10min-FA30 (248.5 101.6) were significantly higher than that of the 20min-FA10 (187.4 77.4) (p < 0.001). The mean CNR difference between the two image groups was 61.2 56.8. There was no significant difference in detection sensitivity of FHLs for two readers between 10min-FA30 (mean 97.7%) and 20min-FA10 (mean 97.9%), irrespective of the lesion size or malignancy. Conclusion 10min-FA30 yielded higher CNR with similar sensitivity compared to 20min-FA10. This finding indicates that 10min-FA30 can potentially replace 20min-FA10 with higher diagnostic performance and save 10 minutes of time. PMID:26444677

  15. Dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) of photodynamic therapy (PDT) outcome and associated changes in the blood-brain barrier following Pc 4-PDT of glioma in an athymic nude rat model

    NASA Astrophysics Data System (ADS)

    Belle, Vaijayantee; Anka, Ali; Cross, Nathan; Thompson, Paul; Mott, Eric; Sharma, Rahul; Gray, Kayla; Zhang, Ruozhen; Xu, Yueshuo; Sun, Jiayang; Flask, Chris A.; Oleinick, Nancy L.; Dean, David

    2012-02-01

    Introduction: Dynamic Contrast-Enhanced-Magnetic Resonance Imaging (DCE-MRI) appears to provide an unambiguous means of tracking the outcome of photodynamic therapy (PDT) of brain tumors with the photosensitizer Pc 4. The increase in Gd enhancement observed after Pc 4-PDT may be due to a temporary opening of the blood-brain-barrier which, as noted by others, may offer a therapeutic window. Methods: We injected 2.5 x 105 U87 cells into the brains of 9 athymic nude rats. After 8-9 days peri-tumor DCE-MRI images were acquired on a 7.0 T microMRI scanner before and after the administration of 150 ?L Gd. DCE-MRI scans were repeated three times following Pc 4-PDT. Results: The average, normalized peak enhancement in the tumor region, approximately 30-90 seconds after Gd administration, was 1.31 times greater than baseline (0.03 Standard Error [SE]) prior to PDT and was 1.44 (0.02 SE) times baseline in the first Post-PDT scans (Day 11), a statistically significant (p ~ 0.014, N=8) increase over the Pre- PDT scans, and was 1.38 (0.02 SE) times baseline in the second scans (Day 12), also a statistically significant (p ~ 0.008, N=7) increase. Observations were mixed in the third Post-PDT scans (Day 13), averaging 1.29 (0.03 SE) times baseline (p ~ 0.66, N=7). Overall a downward trend in enhancement was observed from the first to the third Post-PDT scans. Discussion: DCE-MRI may provide an unambiguous indication of brain tumor PDT outcome. The initial increase in DCE-MRI signal may correlate with a temporary, PDT-induced opening of the blood-brain-barrier, creating a potential therapeutic window.

  16. Laser-induced thermotherapy (LITT) for the treatment of liver metastases: the correlation of Gd-DTPA-enhanced magnetic resonance imaging (MRI) and histomorphological findings in the chronic model

    NASA Astrophysics Data System (ADS)

    Isbert, Christoph M.; Germer, Christoph-Thomas; Albrecht, Dirk; Schilling, Andreas; Heiniche, Antje; Roggan, Andre; Wolf, Karl J.; Mueller, Gerhard J.; Buhr, Heinz-Johannes

    1997-05-01

    The purpose of the study was to evaluate Gd-DTPA-enhanced MRI for the follow-up of laser-induced thermotherapy (LITT) in the treatment of liver metastases. Interstitial laser-induced thermotherapy (LITT) was performed in 55 chinchilla bastard rabbits with a Nd:YAG laser and a specially developed diffuser tip applicator. The animals were examined at different times using MRI and histological methods. T1-weighted spin-echo sequences were made with gadolinium-DTPA and submitted to correlation analysis. The analysis yielded a good correlation (r equals 0.96) between the largest lesion diameters. Lesions showed discontinuous regeneration kinetics with a 41% volume reduction 1 month after LITT. MRI of the lesion directly after LITT showed a hyperintense transition zone. Following the application of intravenous contrast medium, transition zone enhancement was first seen 72 - 96 hours after LITT. Even after 6 months, the laser-induced lesion is visualized as a non-enhanced area. Lesion regeneration followed the principles of wound healing. It is concluded that gadolinium-DTPA- enhanced MRI yielded definitive criteria for the follow-up assessment of LITT.

  17. Dynamic nuclear polarization properties of nitroxyl radicals used in Overhauser-enhanced MRI for simultaneous molecular imaging

    NASA Astrophysics Data System (ADS)

    Benial, A. Milton Franklin; Ichikawa, Kazuhiro; Murugesan, Ramachandran; Yamada, Ken-ichi; Utsumi, Hideo

    2006-10-01

    DNP parameters relevant to Overhauser-enhanced magnetic resonance imaging (OMRI) are reported for a few nitroxyl radicals and their corresponding 15N and 2H enriched analogues, used in simultaneous imaging by OMRI. DNP enhancement was measured at 14.529 mT, using a custom-built scanner operating in a field-cycled mode, for different concentrations, ESR irradiation times and RF power levels. DNP enhancements increased with agent concentration up to 2.5 mM and decreased above 3 mM, in tune with ESR line broadening measured at X-band as a function of the agent concentration. The proton spin-lattice relaxation times ( T1) measured at very low Zeeman field (14.529 mT) and the longitudinal relaxivity parameters were estimated. The relaxivity parameters were in good agreement with those independently computed from the linear region of the concentration dependent enhancement. The leakage factor showed an asymptotic increase with increasing agent concentration. The coupling parameters of 14N- and 15N-labeled carbamoyl-PROXYL showed the interaction between the electron and nuclear spins to be mainly dipolar in origin. Upon 2H labeling, about 70% and 40% increases in enhancement for 15N- and 14N-labeled nitroxyl agents were observed, respectively. It is envisaged that the results reported here may enable better understanding of the factors determining DNP enhancement to design suitable 'beacons' for simultaneous molecular imaging by OMRI.

  18. A model-constrained Monte Carlo method for blind arterial input function estimation in dynamic contrast-enhanced MRI: I. Simulations

    NASA Astrophysics Data System (ADS)

    Schabel, Matthias C.; Fluckiger, Jacob U.; DiBella, Edward V. R.

    2010-08-01

    Widespread adoption of quantitative pharmacokinetic modeling methods in conjunction with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has led to increased recognition of the importance of obtaining accurate patient-specific arterial input function (AIF) measurements. Ideally, DCE-MRI studies use an AIF directly measured in an artery local to the tissue of interest, along with measured tissue concentration curves, to quantitatively determine pharmacokinetic parameters. However, the numerous technical and practical difficulties associated with AIF measurement have made the use of population-averaged AIF data a popular, if sub-optimal, alternative to AIF measurement. In this work, we present and characterize a new algorithm for determining the AIF solely from the measured tissue concentration curves. This Monte Carlo blind estimation (MCBE) algorithm estimates the AIF from the subsets of D concentration-time curves drawn from a larger pool of M candidate curves via nonlinear optimization, doing so for multiple (Q) subsets and statistically averaging these repeated estimates. The MCBE algorithm can be viewed as a generalization of previously published methods that employ clustering of concentration-time curves and only estimate the AIF once. Extensive computer simulations were performed over physiologically and experimentally realistic ranges of imaging and tissue parameters, and the impact of choosing different values of D and Q was investigated. We found the algorithm to be robust, computationally efficient and capable of accurately estimating the AIF even for relatively high noise levels, long sampling intervals and low diversity of tissue curves. With the incorporation of bootstrapping initialization, we further demonstrated the ability to blindly estimate AIFs that deviate substantially in shape from the population-averaged initial guess. Pharmacokinetic parameter estimates for Ktrans, kep, vp and ve all showed relative biases and uncertainties of less than 10% for measurements having a temporal sampling rate of 4 s and a concentration measurement noise level of ? = 0.04 mM. A companion paper discusses the application of the MCBE algorithm to DCE-MRI data acquired in eight patients with malignant brain tumors.

  19. Dynamic Contrast-Enhanced MRI of the Prostate With High Spatiotemporal Resolution Using Compressed Sensing, Parallel Imaging, and Continuous Golden-Angle Radial Sampling: Preliminary Experience

    PubMed Central

    Rosenkrantz, Andrew B.; Geppert, Christian; Grimm, Robert; Block, Tobias K.; Glielmi, Christian; Feng, Li; Otazo, Ricardo; Ream, Justin M.; Romolo, Melanie Moccaldi; Taneja, Samir S.; Sodickson, Daniel K.; Chandarana, Hersh

    2014-01-01

    Purpose To demonstrate dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) of the prostate with both high spatial and temporal resolution via a combination of golden-angle radial k-space sampling, compressed sensing, and parallel-imaging reconstruction (GRASP), and to compare image quality and lesion depiction between GRASP and conventional DCE in prostate cancer patients. Materials and Methods Twenty prostate cancer patients underwent two 3T prostate MRI examinations on separate dates, one using standard DCE (spatial resolution 3.0 1.9 1.9 mm, temporal resolution 5.5 sec) and the other using GRASP (spatial resolution 3.0 1.1 1.1 mm, temporal resolution 2.3 sec). Two radiologists assessed measures of image quality and dominant lesion size. The experienced reader recorded differences in contrast arrival times between the dominant lesion and benign prostate. Results Compared with standard DCE, GRASP demonstrated significantly better clarity of the capsule, peripheral/ transition zone boundary, urethra, and periprostatic vessels; image sharpness; and lesion conspicuity for both readers (P<0.0010.020). GRASP showed improved interreader correlation for lesion size (GRASP: r=0.6910.824, standard: r=0.4950.542). In 8/20 cases, only GRASP showed earlier contrast arrival in tumor than benign; in no case did only standard DCE show earlier contrast arrival in tumor. Conclusion High spatiotemporal resolution prostate DCE is possible with GRASP, which has the potential to improve image quality and lesion depiction as compared with standard DCE. PMID:24833417

  20. Gadofullerene MRI contrast agents.

    PubMed

    Bolskar, Robert D

    2008-04-01

    A promising new class of MRI contrast-enhancing agents with high relaxivities is based on gadolinium-containing metallofullerenes, which are also termed gadofullerenes. Detailed study of the water-proton relaxivity properties and intermolecular nanoclustering behavior of gadofullerene derivatives has revealed valuable information about their relaxivity mechanisms and given a deeper understanding of this new class of paramagnetic contrast agent. Here, the latest findings on water-solubilized gadofullerene materials and how these findings relate to their future applications in MRI are reviewed and discussed. PMID:18373426

  1. Targeted signal-amplifying enzymes enhance MRI of EGFR expression in an orthotopic model of human glioma.

    PubMed

    Shazeeb, Mohammed S; Sotak, Christopher H; DeLeo, Michael; Bogdanov, Alexei

    2011-03-15

    Epidermal growth factor receptor (EGFR) imaging in brain tumors is essential to visualize overexpression of EGFRvIII variants as a signature of highly aggressive gliomas and to identify patients that would benefit from anti-EGFR therapy. Seeking imaging improvements, we tested a novel pretargeting approach that relies on initial administration of enzyme-linked anti-EGFR monoclonal antibodies (mAb; EMD72000) followed by administration of a low-molecular-weight paramagnetic molecule (diTyr-GdDTPA) retained at the site of EGFR mAb accumulation. We hypothesized that diTyr-GdDTPA would become enzyme activated and retained on cells due to binding to tissue proteins. In support of this hypothesis, mAb-enzyme conjugates reacted with both membrane-isolated wild-type (wt) EGFR and EGFRvIII, but they bound primarily to EGFRvIII-expressing cells and not to EGFRwt-expressing cells. In vivo analysis of magnetic resonance (MR) tumor signal revealed differences in MR signal decay following diTyr-GdDTPA substrate administration. These differences were significant in that they suggested differences in substrate elimination from the tissue which relied on the specificity of the initial mAb binding: a biexponential signal decay was observed in tumors only upon preinjection with EGFR-targeted conjugates. Endpoint MRI in this setting revealed detailed images of tumors which correlated with immunohistochemical detection of EGFR expression. Together, our findings suggest an improved method to identify EGFRvIII-expressing gliomas in vivo that are best suited for treatment with therapeutic EGFR antibodies. PMID:21245103

  2. IMRT boost dose planning on dominant intraprostatic lesions: Gold marker-based three-dimensional fusion of CT with dynamic contrast-enhanced and {sup 1}H-spectroscopic MRI

    SciTech Connect

    Lin, Emile N.J.T. van . E-mail: E.vanLin@rther.umcn.nl; Fuetterer, Jurgen J.; Heijmink, Stijn W.T.P.J.; Vight, Lisette P. van der; Hoffmann, Aswin L.; Kollenburg, Peter van; Huisman, Henk Jan J.; Scheenen, Tom W.J.; Witjes, J. Alfred; Leer, Jan Willem; Barentsz, Jelle O.; Visser, Andries G.

    2006-05-01

    Purpose: To demonstrate the theoretical feasibility of integrating two functional prostate magnetic resonance imaging (MRI) techniques (dynamic contrast-enhanced MRI [DCE-MRI] and {sup 1}H-spectroscopic MRI [MRSI]) into inverse treatment planning for definition and potential irradiation of a dominant intraprostatic lesion (DIL) as a biologic target volume for high-dose intraprostatic boosting with intensity-modulated radiotherapy (IMRT). Methods and Materials: In 5 patients, four gold markers were implanted. An endorectal balloon was inserted for both CT and MRI. A DIL volume was defined by DCE-MRI and MRSI using different prostate cancer-specific physiologic (DCE-MRI) and metabolic (MRSI) parameters. CT-MRI registration was performed automatically by matching three-dimensional gold marker surface models with the iterative closest point method. DIL-IMRT plans, consisting of whole prostate irradiation to 70 Gy and a DIL boost to 90 Gy, and standard IMRT plans, in which the whole prostate was irradiated to 78 Gy were generated. The tumor control probability and rectal wall normal tissue complication probability were calculated and compared between the two IMRT approaches. Results: Combined DCE-MRI and MRSI yielded a clearly defined single DIL volume (range, 1.1-6.5 cm{sup 3}) in all patients. In this small, selected patient population, no differences in tumor control probability were found. A decrease in the rectal wall normal tissue complication probability was observed in favor of the DIL-IMRT plan versus the plan with IMRT to 78 Gy. Conclusion: Combined DCE-MRI and MRSI functional image-guided high-dose intraprostatic DIL-IMRT planned as a boost to 90 Gy is theoretically feasible. The preliminary results have indicated that DIL-IMRT may improve the therapeutic ratio by decreasing the normal tissue complication probability with an unchanged tumor control probability. A larger patient population, with more variations in the number, size, and localization of the DIL, and a feasible mechanism for treatment implementation has to be studied to extend these preliminary tumor control and toxicity estimates.

  3. MRI Primer

    SciTech Connect

    Oldendorf, W.; Oldendorf, W. Jr.

    1991-01-01

    Designed for studies, radiologists, and clinicians at all levels of training, this book provides a basic introduction to the principles, physics, and instrumentation of magnetic resonance imaging. The fundamental concepts that are essential for the optimal clinical use of MRI are thoroughly explained in easily accessible terms. To facilitate the reader's comprehension, the material is presented nonmathematically, using no equations and a minimum of symbols and abbreviations. MRI Primer presents a clear account of the phenomenon of nuclear magnetic resonance and the use of gradient magnetic fields to create clinically useful images of cross-sectional slices. Close attention is given to the magnetization vector as a means of expressing nuclear behavior, the role of T{sub 1} and T{sub 2} weighing in imaging, the use of contrast agents, and the pulse sequences most often used in clinical practice, as well as to the relative capabilities and limitations of MRI and CT. The basic hardware components of an MRI scanner are described in detail. Sample MRI scans illustrate how MRI characterizes tissue. An appendix provides a brief introduction to quantum processes in MRI.

  4. Repeat Targeted Prostate Biopsy under Guidance of Multiparametric MRI-Correlated Real-Time Contrast-Enhanced Ultrasound for Patients with Previous Negative Biopsy and Elevated Prostate-Specific Antigen: A Prospective Study

    PubMed Central

    Jang, Dong Ryul; Jung, Dae Chul; Oh, Young Taik; Noh, Songmi; Han, Kyunghwa; Kim, Kiwook; Rha, Koon-Ho; Choi, Young Deuk; Hong, Sung Joon

    2015-01-01

    Objectives To prospectively determine whether multi-parametric MRI (mpMRI) - contrast-enhanced ultrasound (CEUS) correlated, imaging-guided target biopsy (TB) method could improve the detection of prostate cancer in re-biopsy setting of patients with prior negative biopsy. Methods From 2012 to 2014, a total of 42 Korean men with a negative result from previous systematic biopsy (SB) and elevated prostate-specific antigen underwent 3T mpMRI and real-time CEUS guided TB. Target lesions were determined by fusion of mpMRI and CEUS. Subsequently, 12-core SB was performed by a different radiologist. We compared core-based cancer detection rates (CaDR) using the generalized linear mixed model (GLIMMIX) for each biopsy method. Results Core-based CaDR was higher in TB (17.92%, 38 of 212 cores) than in SB (6.15%, 31 of 504 cores) (p < 0.0001; GLIMMIX). In the cancer-positive TB cores, CaDR with suspicious lesions by mpMRI was higher than that by CEUS (86.8% vs. 60.5%, p= 0.02; paired t-test) and concordant rate between mpMRI and CEUS was significantly different with discordant rate (48% vs. 52%, p=0.04; McNemars test). Conclusion The mpMRI-CEUS correlated TB technique for the repeat prostate biopsy of patients with prior negative biopsy can improve CaDR based on the number of cores taken. PMID:26083348

  5. Response of HT29 Colorectal Xenograft Model to Cediranib Assessed with 18F-FMISO PET, Dynamic Contrast-Enhanced and Diffusion-Weighted MRI

    PubMed Central

    Bokacheva, Louisa; Kotedia, Khushali; Reese, Megan; Ricketts, Sally-Ann; Halliday, Jane; Le, Carl H.; Koutcher, Jason A.; Carlin, Sean

    2012-01-01

    Cediranib (AZD2171, AstraZeneca, UK) is a small-molecule pan-VEGFR inhibitor. The tumor response to short-term cediranib treatment was studied using dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) MRI at 7 T as well as 18F-fluoromisonidazle (18F-FMISO) PET and histological markers. Rats bearing subcutaneous HT29 human colorectal tumors were imaged at baseline, then received three doses of cediranib (3 mg/kg per dose daily) or vehicle (dosed daily), with follow up imaging performed 2 hours after the final cediranib or vehicle dose. Tumors were excised and evaluated for the perfusion marker Hoechst 33342, endothelial cell marker CD31, smooth muscle actin (SMA), intercapillary distance (ICD) and tumor necrosis. DCE-MRI-derived parameters decreased significantly in cediranib-treated tumors relative to pre-treatment values: the muscle-normalized initial area under the gadolinium concentration curve (nIAUC90) by 48% (p = 0.002), the enhancing fraction (EnF) by 43% (p = 0.003) and Ktrans by 57% (p = 0.003), but remained unchanged in controls. No change between pre- and post-treatment tumor apparent diffusion coefficient (ADC) in either cediranib- or vehicle-treated group was observed over the course of this study. 18F-FMISO SUVmean decreased by 33% (p = 0.008) in the cediranib group, but showed no significant change in the control group. Histological analysis showed that the number of CD31-positive vessels (59 per mm2), the fraction of SMA-positive vessels (80 to 87%) and ICD (0.17 mm) were similar in cediranib- and vehicle-treated groups. The fraction of perfused blood vessels in cediranib-treated tumors (817%) was lower than in vehicle controls (913%, p = 0.02). The necrotic fraction was slightly higher in cediranib-treated rats (3412%) than in controls (2610%, p = 0.23). These findings suggest that short-term treatment with cediranib causes a decrease of tumor perfusion/permeability across the tumor cross-section, but changes in vascular morphology, vessel density or tumor cellularity do not manifest at this early time point. PMID:22777834

  6. MRI-detectable polymeric micelles incorporating platinum anticancer drugs enhance survival in an advanced hepatocellular carcinoma model

    PubMed Central

    Vinh, Nguyen Quoc; Naka, Shigeyuki; Cabral, Horacio; Murayama, Hiroyuki; Kaida, Sachiko; Kataoka, Kazunori; Morikawa, Shigehiro; Tani, Tohru

    2015-01-01

    Hepatocellular carcinoma (HCC) is one of the most intractable and lethal cancers; most cases are diagnosed at advanced stages with underlying liver dysfunction and are frequently resistant to conventional chemotherapy and radiotherapy. The development of tumor-targeting systems may improve treatment outcomes. Nanomedicine platforms are of particular interest for enhancing chemotherapeutic efficiency, and they include polymeric micelles, which enable targeting of multiple drugs to solid tumors, including imaging and therapeutic agents. This allows concurrent diagnosis, targeting strategy validation, and efficacy assessment. We used polymeric micelles containing the T1-weighted magnetic resonance imaging contrast agent gadolinium-diethylenetriaminpentaacetic acid (Gd-DTPA) and the parent complex of the anticancer drug oxaliplatin [(1,2-diaminocyclohexane)platinum(II) (DACHPt)] for simultaneous imaging and therapy in an orthotopic rat model of HCC. The Gd-DTPA/DACHPt-loaded micelles were injected into the hepatic artery, and magnetic resonance imaging performance and antitumor activity against HCC, as well as adverse drug reactions were assessed. After a single administration, the micelles achieved strong and specific tumor contrast enhancement, induced high levels of tumor apoptosis, and significantly suppressed tumor size and growth. Moreover, the micelles did not induce severe adverse reactions and significantly improved survival outcomes in comparison to oxaliplatin or saline controls. Our results suggest that Gd-DTPA/DACHPt-loaded micelles are a promising approach for effective diagnosis and treatment of advanced HCC. PMID:26203241

  7. MRI-detectable polymeric micelles incorporating platinum anticancer drugs enhance survival in an advanced hepatocellular carcinoma model.

    PubMed

    Vinh, Nguyen Quoc; Naka, Shigeyuki; Cabral, Horacio; Murayama, Hiroyuki; Kaida, Sachiko; Kataoka, Kazunori; Morikawa, Shigehiro; Tani, Tohru

    2015-01-01

    Hepatocellular carcinoma (HCC) is one of the most intractable and lethal cancers; most cases are diagnosed at advanced stages with underlying liver dysfunction and are frequently resistant to conventional chemotherapy and radiotherapy. The development of tumor-targeting systems may improve treatment outcomes. Nanomedicine platforms are of particular interest for enhancing chemotherapeutic efficiency, and they include polymeric micelles, which enable targeting of multiple drugs to solid tumors, including imaging and therapeutic agents. This allows concurrent diagnosis, targeting strategy validation, and efficacy assessment. We used polymeric micelles containing the T1-weighted magnetic resonance imaging contrast agent gadolinium-diethylenetriaminpentaacetic acid (Gd-DTPA) and the parent complex of the anticancer drug oxaliplatin [(1,2-diaminocyclohexane)platinum(II) (DACHPt)] for simultaneous imaging and therapy in an orthotopic rat model of HCC. The Gd-DTPA/DACHPt-loaded micelles were injected into the hepatic artery, and magnetic resonance imaging performance and antitumor activity against HCC, as well as adverse drug reactions were assessed. After a single administration, the micelles achieved strong and specific tumor contrast enhancement, induced high levels of tumor apoptosis, and significantly suppressed tumor size and growth. Moreover, the micelles did not induce severe adverse reactions and significantly improved survival outcomes in comparison to oxaliplatin or saline controls. Our results suggest that Gd-DTPA/DACHPt-loaded micelles are a promising approach for effective diagnosis and treatment of advanced HCC. PMID:26203241

  8. Augmenting atypical antipsychotics with a cognitive enhancer (donepezil) improves regional brain activity in schizophrenia patients: a pilot double-blind placebo controlled BOLD fMRI study.

    PubMed

    Nahas, Ziad; George, Mark S; Horner, Michael D; Markowitz, John S; Li, Xingbao; Lorberbaum, Jeffrey P; Owens, Susan D; McGurk, Susan; DeVane, Lindsay; Risch, S Craig

    2003-06-01

    Cognitive impairments are cardinal features of schizophrenia and predictors of poor vocational and social outcome. Imaging studies with verbal fluency tasks (VFT) lead some to suggest that in schizophrenia, the combination of a failure to deactivate the left temporal lobe and a hypoactive frontal lobe reflects a functional disconnectivity between the left prefrontal cortex and temporal lobe. Others have theorized that an abnormal cingulate gyrus modulates such fronto-temporal connectivity. Thus addition of a cognitive enhancing medication to current antipsychotic therapy might improve functionality of networks necessary in working memory and internal concept generation. To test this hypothesis, we serially measured brain activity in 6 subjects on stable atypical antipsychotics performing a VFT, using BOLD fMRI. Measurements were made at baseline and again after groups were randomized to receive 12 weeks of donepezil (an acetylcholinesterase inhibitor) and placebo in a blind cross-over design. Donepezil addition provided a functional normalization with an increase in left frontal lobe and cingulate activity when compared to placebo and from baseline scans. This pilot study supports the cingulate's role in modulating cognition and neuronal connectivity in schizophrenia. PMID:12925933

  9. Combined Application of Gadoxetic Acid Disodium-Enhanced Magnetic Resonance Imaging (MRI) and Diffusion-Weighted Imaging (DWI) in the Diagnosis of Chronic Liver Disease-Induced Hepatocellular Carcinoma: A Meta-Analysis

    PubMed Central

    Li, Xiang; Li, Chenxia; Wang, Rong; Ren, Juan

    2015-01-01

    Objective Gadoxetic acid disodium (Gd-EOB-DTPA) is a magnetic resonance imaging (MRI) contrast agent to target the liver cells with normal function. In clinical practice, the Gd-EOB-DTPA produces high quality hepatocyte specific image 20 minutes after intravenous injection, so DWI sequence is often performed after the conventional dynamic scanning. However, there are still some disputes about whether DWI sequence will provide more effective diagnostic information in clinical practice. This study aimed to explore the diagnostic value of combining Gd-EOB-DTPA-enhanced MRI and DWI in the detection of hepatocellular carcinoma (HCC) in patients with chronic liver disease. Methods A systematic literature search was performed in the PubMed and Cochrane library database up to March 2015. The quality assessment of diagnostic accuracy studies (QUADAS) was used to evaluate the quality of studies. Heterogeneous test on the included literature was performed by using the software Review Manager 5.3. The MetaDiSc 1.4 software was used to calculate the pooled sensitivity, specificity, positive likelihood ratio and negative likelihood ratio; meanwhile the summary receiver operating characteristics (SROC) curve was drawn to compare the diagnostic performance. Results A total of 13 literatures were included in this study. In 8 literatures regarding HCC diagnosis based on Gd-EOB-DTPA-enhanced MRI, the pooled sensitivity: 0.90 (95% confidence interval (CI): 0.880.93); specificity: 0.89 (95% CI: 0.850.92); positive likelihood ratio: 8.60 (95% CI: 6.2011.92); negative likelihood ratio: 0.10 (95% CI: 0.080.14) were obtained. The area under curve (AUC) and Q values were 0.96 and 0.90, respectively. In 5 literatures relating to HCC diagnosis by combination of Gd-EOB-DTPA-enhanced MRI and DWI sequence, the pooled sensitivity: 0.88 (95% CI: 0.850.91), specificity: 0.96 (0.940.97), positive likelihood ratio: 19.63 (12.7730.16), negative likelihood ratio: 0.10 (0.070.14) were obtained. The AUC value was 0.9833 and Q value was 0.9436. The AUC value of comprehensive evaluation method was significantly higher than that of Gd-EOB-DTPA-enhanced MRI alone(P<0.05). Conclusion Combination of Gd-EOB-DTPA-enhanced MRI and DWI sequence significantly improves in both the diagnostic accuracy and specificity of chronic liver disease-associated HCC. PMID:26629904

  10. Magnetic Resonance Imaging (MRI) with retrograde intralumen contrast enhancement of the rectum in diagnostics of rectovaginal fistulas after combination therapy of rectal cancer. Experience of application

    NASA Astrophysics Data System (ADS)

    Usova, A.; Frolova, I.; Afanasev, S.; Tarasova, A.; Molchanov, S.

    2016-02-01

    Experiment of use of MRI in diagnostics of rectovaginal fistulas after combination therapy of rectal cancer is shown on clinical examples. We used retrograde contrasting of a rectum with 150ml ultrasonic gel to make MRI more informative in case of low diagnostic efficiency of ultrasound, colonoscopy and gynecological examination.

  11. Manganese-Enhanced MRI Reflects Both Activity-Independent and Activity-Dependent Uptake within the Rat Habenulomesencephalic Pathway

    PubMed Central

    Brown, P. Leon; Rea, William; Vaupel, Bruce; Yang, Yihong; Stein, Elliot; Shepard, Paul D.

    2015-01-01

    Manganese-enhanced magnetic resonance imaging (MEMRI) is a powerful technique for assessing the functional connectivity of neurons within the central nervous system. Despite the widely held proposition that MEMRI signal is dependent on neuronal activity, few studies have directly tested this implicit hypothesis. In the present series of experiments, MnCl2 was injected into the habenula of urethane-anesthetized rats alone or in combination with drugs known to alter neuronal activity by modulating specific voltage- and/or ligand-gated ion channels. Continuous quantitative T1 mapping was used to measure Mn2+ accumulation in the interpeduncular nucleus, a midline structure in which efferents from the medial habenula terminate. Microinjection of MnCl2 into the habenular complex using a protocol that maintained spontaneous neuronal activity resulted in a time-dependent increase in MEMRI signal intensity in the interpeduncular nucleus consistent with fast axonal transport of Mn2+ between these structures. Co-injection of the excitatory amino-acid agonist AMPA, increased the Mn2+-enhanced signal intensity within the interpeduncular nucleus. AMPA-induced increases in MEMRI signal were attenuated by co-injection of either the sodium channel blocker, TTX, or broad-spectrum Ca2+ channel blocker, Ni2+, and were occluded in the presence of both channel blockers. However, neither Ni2+ nor TTX, alone or in combination, attenuated the increase in signal intensity following injection of Mn2+ into the habenula. These results support the premise that changes in neuronal excitability are reflected by corresponding changes in MEMRI signal intensity. However, they also suggest that basal rates of Mn2+ uptake by neurons in the medial habenula may also occur via activity-independent mechanisms. PMID:26009889

  12. Dynamic Contrast Enhanced MRI Detects Early Response to Adoptive NK Cellular Immunotherapy Targeting the NG2 Proteoglycan in a Rat Model of Glioblastoma

    PubMed Central

    Thuen, Marte; Gras Navarro, Andrea; Huuse, Else Marie; Thorsen, Frits; Poli, Aurelie; Zimmer, Jacques; Haraldseth, Olav; Lie, Stein Atle; Enger, Per yvind; Chekenya, Martha

    2014-01-01

    There are currently no established radiological parameters that predict response to immunotherapy. We hypothesised that multiparametric, longitudinal magnetic resonance imaging (MRI) of physiological parameters and pharmacokinetic models might detect early biological responses to immunotherapy for glioblastoma targeting NG2/CSPG4 with mAb9.2.27 combined with natural killer (NK) cells. Contrast enhanced conventional T1-weighted MRI at 71 and 172 days post-treatment failed to detect differences in tumour size between the treatment groups, whereas, follow-up scans at 3 months demonstrated diminished signal intensity and tumour volume in the surviving NK+mAb9.2.27 treated animals. Notably, interstitial volume fraction (ve), was significantly increased in the NK+mAb9.2.27 combination therapy group compared mAb9.2.27 and NK cell monotherapy groups (p?=?0.002 and p?=?0.017 respectively) in cohort 1 animals treated with 1 million NK cells. ve was reproducibly increased in the combination NK+mAb9.2.27 compared to NK cell monotherapy in cohort 2 treated with increased dose of 2 million NK cells (p<0.0001), indicating greater cell death induced by NK+mAb9.2.27 treatment. The interstitial volume fraction in the NK monotherapy group was significantly reduced compared to mAb9.2.27 monotherapy (p<0.0001) and untreated controls (p?=?0.014) in the cohort 2 animals. NK cells in monotherapy were unable to kill the U87MG cells that highly expressed class I human leucocyte antigens, and diminished stress ligands for activating receptors. A significant association between apparent diffusion coefficient (ADC) of water and ve in combination NK+mAb9.2.27 and NK monotherapy treated tumours was evident, where increased ADC corresponded to reduced ve in both cases. Collectively, these data support histological measures at end-stage demonstrating diminished tumour cell proliferation and pronounced apoptosis in the NK+mAb9.2.27 treated tumours compared to the other groups. In conclusion, ve was the most reliable radiological parameter for detecting response to intralesional NK cellular therapy. PMID:25268630

  13. Reproducibility of Dynamic Contrast-Enhanced MRI in Renal Cell Carcinoma: A Prospective Analysis on Intra- and Interobserver and Scan-Rescan Performance of Pharmacokinetic Parameters.

    PubMed

    Wang, Haiyi; Su, Zihua; Ye, Huiyi; Xu, Xiao; Sun, Zhipeng; Li, Lu; Duan, Feixue; Song, Yuanyuan; Lambrou, Tryphon; Ma, Lin

    2015-09-01

    The objective of this study was to investigate the intra- and interobserver as well as scan-rescan reproducibility of quantitative parameters of renal cell carcinomas (RCCs) with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). A total of 21 patients with clear cell RCCs (17 men, 4 woman; age 37-69 years, mean age 54.6 years, mean size, 5.0??2.2?cm) were prospectively recruited from September 2012 to November 2012. Patients underwent paired DCE-MRI studies on a 3.0 T MR system with an interval of 48 to 72 hours. The extended-Tofts model and population-based arterial input function were used to calculate kinetic parameters. Three observers defined the 2-dimensional whole-tumor region of interest at the slice with the maximum diameter of the RCC. Intraobserver and scan-rescan differences were assessed using paired t tests, whereas interobserver differences using two-way analysis of variance. Intra- and interobserver reproducibility and scan-rescan reproducibility were evaluated using within-subject coefficient of variation (wCoV) and intraclass correlation coefficient (ICC). There were no significant intra-, interobserver, or scan-rescan differences in parameters (all P?>?0.05). All ICCs for intra- and interobserver agreements were >0.75 (P?30%). DCE-MRI demonstrated good intra- and interobserver reproducibility and moderate to good scan-rescan performance in the assessment of RCC using K(trans), K(ep), and V(e) as parameters under noncontinuous scanning mode. V(p) showed poor reproducibility, and thus may not be suitable for this scanning protocol. PMID:26376399

  14. A model-constrained Monte Carlo method for blind arterial input function estimation in dynamic contrast-enhanced MRI: II. In vivo results

    NASA Astrophysics Data System (ADS)

    Schabel, Matthias C.; DiBella, Edward V. R.; Jensen, Randy L.; Salzman, Karen L.

    2010-08-01

    Accurate quantification of pharmacokinetic model parameters in tracer kinetic imaging experiments requires correspondingly accurate determination of the arterial input function (AIF). Despite significant effort expended on methods of directly measuring patient-specific AIFs in modalities as diverse as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), dynamic positron emission tomography (PET), and perfusion computed tomography (CT), fundamental and technical difficulties have made consistent and reliable achievement of that goal elusive. Here, we validate a new algorithm for AIF determination, the Monte Carlo blind estimation (MCBE) method (which is described in detail and characterized by extensive simulations in a companion paper), by comparing AIFs measured in DCE-MRI studies of eight brain tumor patients with results of blind estimation. Blind AIFs calculated with the MCBE method using a pool of concentration-time curves from a region of normal brain tissue were found to be quite similar to the measured AIFs, with statistically significant decreases in fit residuals observed in six of eight patients. Biases between the blind and measured pharmacokinetic parameters were the dominant source of error. Averaged over all eight patients, the mean biases were +7% in K trans, 0% in kep, -11% in vp and +10% in ve. Corresponding uncertainties (median absolute deviation from the best fit line) were 0.0043?min-1 in K trans, 0.0491 min-1 in kep, 0.29% in vp and 0.45% in ve. The use of a published population-averaged AIF resulted in larger mean biases in three of the four parameters (-23% in K trans, -22% in kep, -63% in vp), with the bias in ve unchanged, and led to larger uncertainties in all four parameters (0.0083 min-1 in K trans, 0.1038 min-1 in kep, 0.31% in vp and 0.95% in ve). When blind AIFs were calculated from a region of tumor tissue, statistically significant decreases in fit residuals were observed in all eight patients despite larger deviations of these blind AIFs from the measured AIFs. The observed decrease in root-mean-square fit residuals between the normal brain and tumor tissue blind AIFs suggests that the local blood supply in tumors is measurably different from that in normal brain tissue and that the proposed method is able to discriminate between the two. We have shown the feasibility of applying the MCBE algorithm to DCE-MRI data acquired in brain, finding generally good agreement with measured AIFs and decreased biases and uncertainties relative to the use of a population-averaged AIF. These results demonstrate that the MCBE algorithm is a useful alternative to direct AIF measurement in cases where acquisition of high-quality arterial input function data is difficult or impossible.

  15. Portable MRI

    SciTech Connect

    Espy, Michelle A.

    2012-06-29

    This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

  16. Comparison of Dynamic Contrast-Enhanced MRI and PET/CT in the Evaluation of Laryngeal Cancer After Inadequate CT Results

    PubMed Central

    Citil, Serdal; Dogan, Serap; Atilgan, Hasan Ikbal; Menzilcioglu, Mehmet Sait; Sahin, Tuna; Abdulrezzak, Ummuhan; Duymus, Mahmut; Ozturk, Mustafa

    2015-01-01

    Summary Background To investigate the diagnostic value of dynamic magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) for laryngeal cancers after inadequate CT results. Material/Methods The study comprised 45 patients investigated for primary laryngeal cancer or recurrence-residue in which CT was considered inadequate. A mass was found in 20 patients. Dynamic MRI and PET/CT were compared for diagnosis of mass, lymph node involvement, recurrence and residue. The dynamic curves formed in dynamic MRI were investigated for diagnostic contributions. Results The sensitivity and specificity of the dynamic MRI, for supraglottic, glottic and subglottic location, was 100%, 80%, and 92%; 100%, 85%, and 100%, respectively. In PET/CT the sensitivity and specificity were 100% for all of those localizations. For lymph node involvement, the sensitivity of dynamic MRI and PET/CT was 100%, the specificity was 100% and 93%, respectively. For recurrence-residue, the sensitivity and specificity of dynamic MRI were 86% and 67%, respectively, with 100% sensitivity and specificity in PET/CT. The sensitivity of type A curve for detection of malignancy was 40%, and specificity was 100%. When type A and B curves were included, the sensitivity was 100%. Conclusions For patients investigated for laryngeal cancer in which CT is considered inadequate, dynamic MRI or PET/CT is useful. PMID:26445625

  17. Optimization of rs-fMRI Pre-processing for Enhanced Signal-Noise Separation, Test-Retest Reliability, and Group Discrimination.

    PubMed

    Shirer, William R; Jiang, Heidi; Price, Collin M; Ng, Bernard; Greicius, Michael D

    2015-08-15

    Resting-state functional magnetic resonance imaging (rs-fMRI) has become an increasingly important tool in mapping the functional networks of the brain. This tool has been used to examine network changes induced by cognitive and emotional states, neurological traits, and neuropsychiatric disorders. However, noise that remains in the rs-fMRI data after preprocessing has limited the reliability of individual-subject results, wherein scanner artifacts, subject movements, and other noise sources induce non-neural temporal correlations in the blood oxygen level-dependent (BOLD) timeseries. Numerous preprocessing methods have been proposed to isolate and remove these confounds; however, the field has not coalesced around a standard preprocessing pipeline. In comparisons, these preprocessing methods are often assessed with only a single metric of rs-fMRI data quality, such as reliability, without considering other aspects in tandem, such as signal-to-noise ratio and group discriminability. The present study seeks to identify the data preprocessing pipeline that optimizes rs-fMRI data across multiple outcome measures. Specifically, we aim to minimize the noise in the data and maximize result reliability, while retaining the unique features that characterize distinct groups. We examine how these metrics are influenced by bandpass filter selection and noise regression in four datasets, totaling 181 rs-fMRI scans and 38 subject-driven memory scans. Additionally, we perform two different rs-fMRI analysis methods - dual regression and region-of-interest based functional connectivity - and highlight the preprocessing parameters that optimize both approaches. Our results expand upon previous reports of individual-scan reliability, and demonstrate that preprocessing parameter selection can significantly change the noisiness, reliability, and heterogeneity of rs-fMRI data. The application of our findings to rs-fMRI data analysis should improve the validity and reliability of rs-fMRI results, both at the individual-subject level and the group level. PMID:25987368

  18. Efficient Hilbert transform-based alternative to Tofts physiological models for representing MRI dynamic contrast-enhanced images in computer-aided diagnosis of prostate cancer

    NASA Astrophysics Data System (ADS)

    Boehm, Kevin M.; Wang, Shijun; Burtt, Karen E.; Turkbey, Baris; Weisenthal, Samuel; Pinto, Peter; Choyke, Peter; Wood, Bradford J.; Petrick, Nicholas; Sahiner, Berkman; Summers, Ronald M.

    2015-03-01

    In computer-aided diagnosis (CAD) systems for prostate cancer, dynamic contrast enhanced (DCE) magnetic resonance imaging is useful for distinguishing cancerous and benign tissue. The Tofts physiological model is a commonly used representation of the DCE image data, but the parameters require extensive computation. Hence, we developed an alternative representation based on the Hilbert transform of the DCE images. The time maximum of the Hilbert transform, a binary metric of early enhancement, and a pre-DCE value was assigned to each voxel and appended to a standard feature set derived from T2-weighted images and apparent diffusion coefficient maps. A cohort of 40 patients was used for training the classifier, and 20 patients were used for testing. The AUC was calculated by pooling the voxel-wise prediction values and comparing with the ground truth. The resulting AUC of 0.92 (95% CI [0.87 0.97]) is not significantly different from an AUC calculated using Tofts physiological models of 0.92 (95% CI [0.87 0.97]), as validated by a Wilcoxon signed rank test on each patient's AUC (p = 0.19). The time required for calculation and feature extraction is 11.39 seconds (95% CI [10.95 11.82]) per patient using the Hilbert-based feature set, two orders of magnitude faster than the 1319 seconds (95% CI [1233 1404]) required for the Tofts parameter-based feature set (p<0.001). Hence, the features proposed herein appear useful for CAD systems integrated into clinical workflows where efficiency is important.

  19. Prelinguistic vocalizations distinguish pointing acts.

    PubMed

    Grünloh, Thomas; Liszkowski, Ulf

    2015-11-01

    The current study investigated whether point-accompanying characteristics, like vocalizations and hand shape, differentiate infants' underlying motives of prelinguistic pointing. We elicited imperative (requestive) and declarative (expressive and informative) pointing acts in experimentally controlled situations, and analyzed accompanying characteristics. Experiment 1 revealed that prosodic characteristics of point-accompanying vocalizations distinguished requestive from both expressive and informative pointing acts, with little differences between the latter two. In addition, requestive points were more often realized with the whole hand than the index finger, while this was the opposite for expressive and informative acts. Experiment 2 replicated Experiment 1, revealing distinct prosodic characteristics for requestive pointing also when the referent was distal and when it had an index-finger shape. Findings reveal that beyond the social context, point-accompanying vocalizations give clues to infants' underlying intentions when pointing. PMID:26435081

  20. HO-1 gene overexpression enhances the beneficial effects of superparamagnetic iron oxide labeled bone marrow stromal cells transplantation in swine hearts underwent ischemia/reperfusion: an MRI study.

    PubMed

    Jiang, Yibo; Chen, Lijuan; Tang, Yaoliang; Ma, Genshan; Shen, Chengxing; Qi, Chunmei; Zhu, Qi; Yao, Yuyu; Liu, Naifeng

    2010-05-01

    To determine the effect of intracoronary transfer of superparamagnetic iron oxide (SPIO) labeled heme oxygenase-1 (HO-1) overexpressed bone marrow stromal cells (BMSCs) in a porcine myocardial ischemia/reperfusion model. Cell apoptosis was assayed and supernatant cytokine concentrations were measured in BMSCs that underwent hypoxia/reoxygen in vitro. Female mini-swines that underwent 1 h LAD occlusion followed by 1 h reperfusion were randomly allocated to receive intracoronary saline (control), 1 x 10(7) SPIO-labeled BMSCs transfected with pcDNA3.1-Lacz plasmid (Lacz-BMSCs), pcDNA3.1-human HO-1 (HO-1-BMSCs), pcDNA3.1-hHO-1 pretreated with a HO inhibitor, tin protoporphyrin (SnPP, n = 10 each). MRI and postmortem histological analysis were made at 1 week or 3 months thereafter. Post hypoxia/reoxygen in vitro, apoptosis was significantly reduced, supernatant VEGF significantly increased while TNF-alpha and IL-6 significantly reduced in HO-1-BMSCs group compared with Lacz-BMSCs group (all p < 0.05). Myocardial expression of VEGF was significantly higher in HO-1-BMSCs than in Lacz-BMSCs group at 1 week post transplantation (all p < 0.05). Signal voids induced by the SPIO were detected in the peri-infarction region in all BMSC groups at 1 week but not at 3 months post transplantation and the extent of the hypointense signal was the highest in HO-1-BMSCs group, and histological analysis showed that signal voids represented cardiac macrophages that engulfed the SPIO-labeled BMSCs. Pretreatment with SnPP significantly attenuated the beneficial effects of HO-1-BMSCs. Transplantation of HO-1-overexpressed BMSCs significantly enhanced the beneficial effects of BMSCs on improving cardiac function in this model. PMID:20033189

  1. Classification of small lesions in dynamic breast MRI: Eliminating the need for precise lesion segmentation through spatio-temporal analysis of contrast enhancement over time.

    PubMed

    Nagarajan, Mahesh B; Huber, Markus B; Schlossbauer, Thomas; Leinsinger, Gerda; Krol, Andrzej; Wismller, Axel

    2013-10-01

    Characterizing the dignity of breast lesions as benign or malignant is specifically difficult for small lesions; they don't exhibit typical characteristics of malignancy and are harder to segment since margins are harder to visualize. Previous attempts at using dynamic or morphologic criteria to classify small lesions (mean lesion diameter of about 1 cm) have not yielded satisfactory results. The goal of this work was to improve the classification performance in such small diagnostically challenging lesions while concurrently eliminating the need for precise lesion segmentation. To this end, we introduce a method for topological characterization of lesion enhancement patterns over time. Three Minkowski Functionals were extracted from all five post-contrast images of sixty annotated lesions on dynamic breast MRI exams. For each Minkowski Functional, topological features extracted from each post-contrast image of the lesions were combined into a high-dimensional texture feature vector. These feature vectors were classified in a machine learning task with support vector regression. For comparison, conventional Haralick texture features derived from gray-level co-occurrence matrices (GLCM) were also used. A new method for extracting thresholded GLCM features was also introduced and investigated here. The best classification performance was observed with Minkowski Functionals area and perimeter, thresholded GLCM features f8 and f9, and conventional GLCM features f4 and f6. However, both Minkowski Functionals and thresholded GLCM achieved such results without lesion segmentation while the performance of GLCM features significantly deteriorated when lesions were not segmented (p < 0.05). This suggests that such advanced spatio-temporal characterization can improve the classification performance achieved in such small lesions, while simultaneously eliminating the need for precise segmentation. PMID:24244074

  2. MR-Guided Near-Infrared Spectral Tomography Increases Diagnostic Performance of Breast MRI

    PubMed Central

    Mastanduno, Michael A.; Xu, Junqing; El-Ghussein, Fadi; Jiang, Shudong; Yin, Hong; Zhao, Yan; Wang, Ke; Ren, Fang; Gui, Jiang; Pogue, Brian W.; Paulsen, Keith D.

    2016-01-01

    Purpose The purpose of this study was to determine the diagnostically most important molecular biomarkers quantified by magnetic resonance-guided (MR) near-infrared spectral tomography (NIRST) that distinguish malignant breast lesions from benign abnormalities when combined with outcomes from clinical breast MRI. Experimental Design The study was HIPAA compliant and approved by the Dartmouth Institutional Review Board, the NIH, the United States State Department, and Xijing Hospital. MR-guided NIRST evaluated hemoglobin, water, and lipid content in regions of interest defined by concurrent dynamic contrast-enhanced MRI (DCE-MRI) in the breast. MRI plus NIRST was performed in 44 subjects (median age, 46, age range, 2081 years), 28 of whom had subsequent malignant pathologic diagnoses, and 16 had benign conditions. A subset of 30 subject examinations yielded optical data that met minimum sensitivity requirements to the suspicious lesion and were included in the analyses of diagnostic performance. Results In the subset of 30 subject examinations meeting minimum optical data sensitivity criterion, the MR-guided NIRST separated malignant from benign lesions using total hemoglobin (HbT; P < 0.01) and tissue optical index (TOI; P < 0.001). Combined MRI plus TOI data caused one false positive and 1 false negative, and produced the best diagnostic performance, yielding an AUC of 0.95, sensitivity of 95%, specificity of 89%, positive predictive value of 95%, and negative predictive value of 89%, respectively. Conclusions MRI plus NIRST results correlated well with histopathologic diagnoses and could provide additional information to reduce the number of MRI-directed biopsies. PMID:26019171

  3. Multimodality Computer-Aided Breast Cancer Diagnosis with FFDM and DCE-MRI

    PubMed Central

    Yuan, Yading; Giger, Maryellen L.; Li, Hui; Bhooshan, Neha; Sennett, Charlene A.

    2015-01-01

    Rationale and Objectives To investigate a multimodality computer-aided diagnosis (CAD) scheme that combines image information from full-field digital mammography (FFDM) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for computerized breast cancer classification. Materials and Methods From a retrospective FFDM database with 432 lesions (255 malignant, 177 benign) and a retrospective DCE-MRI database including 476 lesions (347 malignant, 129 benign), we constructed a multimodality dataset of 213 lesions (168 malignant, 45 benign). Each lesion was present on both FFDM and DCE-MRI images and deemed to be a difficult case given the necessity of having both clinical imaging exams. Using a manually indicated lesion location (ie, a seed point on FFDM images or a region of interest on DCE-MRI images, the computer automatically segmented the mass lesions and extracted lesion features). A subset of features was selected using linear stepwise feature selection and merged by a Bayesian artificial neural network to yield an estimate of the probability of malignancy. Receiver operating characteristic (ROC) analysis was used to evaluate the performance of the selected features in distinguishing between malignant and benign lesions. Results With leave-one-lesion-out cross-validation on the multimodality dataset, the mammography-only features yielded an area under the ROC curve (AUC) of 0.74 0.04, and the DCE-MRI-only features yielded an AUC of 0.78 0.04. The combination of these two modalities, which included a spiculation feature from mammography and two kinetic features from DCE-MRI, yielded an AUC of 0.87 0.03. The improvement of combining multimodality information was statistically significant as compared to the use of single modality information alone. Conclusions A CAD scheme that combines features extracted from FFDM and DCE-MRI images may be advantageous to single-modality CAD in the task of differentiating between malignant and benign lesions. PMID:20692620

  4. A comparison of radial keyhole strategies for high spatial and temporal resolution 4D contrast-enhanced MRI in small animal tumor models

    PubMed Central

    Subashi, Ergys; Moding, Everett J.; Cofer, Gary P.; MacFall, James R.; Kirsch, David G.; Qi, Yi; Allan Johnson, G.

    2013-01-01

    Purpose: Dynamic contrast-enhanced (DCE) MRI has been widely used as a quantitative imaging method for monitoring tumor response to therapy. The simultaneous challenges of increasing temporal and spatial resolution in a setting where the signal from the much smaller voxel is weaker have made this MR technique difficult to implement in small-animal imaging. Existing protocols employed in preclinical DCE-MRI acquire a limited number of slices resulting in potentially lost information in the third dimension. This study describes and compares a family of four-dimensional (3D spatial + time), projection acquisition, radial keyhole-sampling strategies that support high spatial and temporal resolution. Methods: The 4D method is based on a RF-spoiled, steady-state, gradient-recalled sequence with minimal echo time. An interleaved 3D radial trajectory with a quasi-uniform distribution of points in k-space was used for sampling temporally resolved datasets. These volumes were reconstructed with three different k-space filters encompassing a range of possible radial keyhole strategies. The effect of k-space filtering on spatial and temporal resolution was studied in a 5 mM CuSO4 phantom consisting of a meshgrid with 350-μm spacing and in 12 tumors from three cell lines (HT-29, LoVo, MX-1) and a primary mouse sarcoma model (three tumors/group). The time-to-peak signal intensity was used to assess the effect of the reconstruction filters on temporal resolution. As a measure of heterogeneity in the third dimension, the authors analyzed the spatial distribution of the rate of transport (Ktrans) of the contrast agent across the endothelium barrier for several different types of tumors. Results: Four-dimensional radial keyhole imaging does not degrade the system spatial resolution. Phantom studies indicate there is a maximum 40% decrease in signal-to-noise ratio as compared to a fully sampled dataset. T1 measurements obtained with the interleaved radial technique do not differ significantly from those made with a conventional Cartesian spin-echo sequence. A bin-by-bin comparison of the distribution of the time-to-peak parameter shows that 4D radial keyhole reconstruction does not cause significant temporal blurring when a temporal resolution of 9.9 s is used for the subsamples of the keyhole data. In vivo studies reveal substantial tumor heterogeneity in the third spatial dimension that may be missed with lower resolution imaging protocols. Conclusions: Volumetric keyhole imaging with projection acquisition provides a means to increase spatiotemporal resolution and coverage over that provided by existing 2D Cartesian protocols. Furthermore, there is no difference in temporal resolution between the higher spatial resolution keyhole reconstruction and the undersampled projection data. The technique allows one to measure complex heterogeneity of kinetic parameters with isotropic, microscopic spatial resolution. PMID:23387766

  5. In vivo transport of Gd-DTPA2- into human meniscus and cartilage assessed with delayed gadolinium-enhanced MRI of cartilage (dGEMRIC)

    PubMed Central

    2014-01-01

    Background Impaired stability is a risk factor in knee osteoarthritis (OA), where the whole joint and not only the joint cartilage is affected. The meniscus provides joint stability and is involved in the early pathological progress of OA. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) has been used to identify pre-radiographic changes in the cartilage in OA, but has been used less commonly to examine the meniscus, and then using only a double dose of the contrast agent. The purpose of this study was to enable improved early OA diagnosis by investigate the temporal contrast agent distribution in the meniscus and femoral cartilage simultaneously, in healthy volunteers, using 3D dGEMRIC at two different doses of the contrast agent Gd-DTPA2-. Methods The right knee in 12 asymptomatic volunteers was examined using a 3D Look-Locker sequence on two occasions after an intravenous injection of a double or triple dose of Gd-DTPA2- (0.2 or 0.3mmol/kg body weight). The relaxation time (T1) and relaxation rate (R1?=?1/T1) were measured in the meniscus and femoral cartilage before, and 60, 90, 120 and 180minutes after injection, and the change in relaxation rate (?R1) was calculated. Paired t-test and Analysis of Variance (ANOVA) were used for statistical evaluation. Results The triple dose yielded higher concentrations of Gd-DTPA2- in the meniscus and cartilage than the double dose, but provided no additional information. The observed patterns of ?R1 were similar for double and triple doses of the contrast agent. ?R1 was higher in the meniscus than in femoral cartilage in the corresponding compartments at all time points after injection. ?R1 increased until 90-180 minutes in both the cartilage and the meniscus (p?

  6. Delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) Shows No Change in Cartilage Structural Composition after Viscosupplementation in Patients with Early-Stage Knee Osteoarthritis

    PubMed Central

    van Tiel, Jasper; Reijman, Max; Bos, Pieter K.; Hermans, Job; van Buul, Gerben M.; Bron, Esther E.; Klein, Stefan; Verhaar, Jan A. N.; Krestin, Gabriel P.; Bierma-Zeinstra, Sita M. A.; Weinans, Harrie; Kotek, Gyula; Oei, Edwin H. G.

    2013-01-01

    Introduction Viscosupplementation with hyaluronic acid (HA) of osteoarthritic (OA) knee joints has a well-established positive effect on clinical symptoms. This effect, however, is only temporary and the working mechanism of HA injections is not clear. It was suggested that HA might have disease modifying properties because of its beneficial effect on cartilage sulphated glycosaminoglycan (sGAG) content. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is a highly reproducible, non-invasive surrogate measure for sGAG content and hence composition of cartilage. The aim of this study was to assess whether improvement in cartilage structural composition is detected using dGEMRIC 14 weeks after 3 weekly injections with HA in patients with early-stage knee OA. Methods In 20 early-stage knee OA patients (KLG I-II), 3D dGEMRIC at 3T was acquired before and 14 weeks after 3 weekly injections with HA. To evaluate patient symptoms, the knee injury and osteoarthritis outcome score (KOOS) and a numeric rating scale (NRS) for pain were recorded. To evaluate cartilage composition, six cartilage regions in the knee were analyzed on dGEMRIC. Outcomes of dGEMRIC, KOOS and NRS before and after HA were compared using paired t-testing. Since we performed multiple t-tests, we applied a Bonferroni-Holm correction to determine statistical significance for these analyses. Results All KOOS subscales (pain, symptoms, daily activities, sports and quality of life) and the NRS pain improved significantly 14 weeks after Viscosupplementation with HA. Outcomes of dGEMRIC did not change significantly after HA compared to baseline in any of the cartilage regions analyzed in the knee. Conclusions Our results confirm previous findings reported in the literature, showing persisting improvement in symptomatic outcome measures in early-stage knee OA patients 14 weeks after Viscosupplementation. Outcomes of dGEMRIC, however, did not change after Viscosupplementation, indicating no change in cartilage structural composition as an explanation for the improvement of clinical symptoms. PMID:24223194

  7. Assessment of Lumbar Intervertebral Disc Glycosaminoglycan Content by Gadolinium-Enhanced MRI before and after 21-Days of Head-Down-Tilt Bedrest

    PubMed Central

    Koy, Timmo; Zange, Jochen; Rittweger, Jrn; Pohle-Frhlich, Regina; Hackenbroch, Matthias; Eysel, Peer; Ganse, Bergita

    2014-01-01

    During spaceflight, it has been shown that intervertebral discs (IVDs) increase in height, causing elongation of the spine up to several centimeters. Astronauts frequently report dull lower back pain that is most likely of discogenic origin and may result from IVD expansion. It is unknown whether disc volume solely increases by water influx, or if the content of glycosaminoglycans also changes in microgravity. Aim of this pilot study was to investigate effects of the spaceflight analog of bedrest on the glycosaminoglycan content of human lumbar IVDs. Five healthy, non-smoking, male human subjects of European descent were immobilized in 6 head-down-tilt bedrest for 21 days. Subjects remained in bed 24 h a day with at least one shoulder on the mattress. Magnetic Resonance Imaging (MRI) scans were taken according to the delayed gadolinium-enhanced magnetic resonance imaging (dGEMRIC) protocol before and after bedrest. The outcome measures were T1 and ?T1. Scans were performed before and after administration of the contrast agent Gd-DOTA, and differences between T1-values of both scans (?T1) were computed. ?T1 is the longitudinal relaxation time in the tissue and inversely related to the glycosaminoglycan-content. For data analysis, IVDs L1/2 to L4/5 were semi-automatically segmented. Zones were defined and analyzed separately. Results show a highly significant decrease in ?T1 (p<0.001) after bedrest in all IVDs, and in all areas of the IVDs. The ?T1-decrease was most prominent in the nucleus pulposus and in L4/5, and was expressed slightly more in the posterior than anterior IVD. Unexpected negative ?T1-values were found in Pfirrmann-grade 2-discs after bedrest. Significantly lower T1 before contrast agent application was found after bedrest compared to before bedrest. According to the dGEMRIC-literature, the decrease in ?T1 may be interpreted as an increase in glycosaminoglycans in healthy IVDs during bedrest. This interpretation seems contradictory to previous findings in IVD unloading. PMID:25380233

  8. Tumor Metabolism and Perfusion in Head and Neck Squamous Cell Carcinoma: Pretreatment Multimodality Imaging With {sup 1}H Magnetic Resonance Spectroscopy, Dynamic Contrast-Enhanced MRI, and [{sup 18}F]FDG-PET

    SciTech Connect

    Jansen, Jacobus F.A.; Schoeder, Heiko; Lee, Nancy Y.; Stambuk, Hilda E.; Wang Ya; Fury, Matthew G.; Patel, Senehal G.; Pfister, David G.; Shah, Jatin P.; Koutcher, Jason A.; Shukla-Dave, Amita

    2012-01-01

    Purpose: To correlate proton magnetic resonance spectroscopy ({sup 1}H-MRS), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and {sup 18}F-labeled fluorodeoxyglucose positron emission tomography ([{sup 18}F]FDG PET) of nodal metastases in patients with head and neck squamous cell carcinoma (HNSCC) for assessment of tumor biology. Additionally, pretreatment multimodality imaging was evaluated for its efficacy in predicting short-term response to treatment. Methods and Materials: Metastatic neck nodes were imaged with {sup 1}H-MRS, DCE-MRI, and [{sup 18}F]FDG PET in 16 patients with newly diagnosed HNSCC, before treatment. Short-term patient radiological response was evaluated at 3 to 4 months. Correlations among {sup 1}H-MRS (choline concentration relative to water [Cho/W]), DCE-MRI (volume transfer constant [K{sup trans}]; volume fraction of the extravascular extracellular space [v{sub e}]; and redistribution rate constant [k{sub ep}]), and [{sup 18}F]FDG PET (standard uptake value [SUV] and total lesion glycolysis [TLG]) were calculated using nonparametric Spearman rank correlation. To predict short-term responses, logistic regression analysis was performed. Results: A significant positive correlation was found between Cho/W and TLG ({rho} = 0.599; p = 0.031). Cho/W correlated negatively with heterogeneity measures of standard deviation std(v{sub e}) ({rho} = -0.691; p = 0.004) and std(k{sub ep}) ({rho} = -0.704; p = 0.003). Maximum SUV (SUVmax) values correlated strongly with MRI tumor volume ({rho} = 0.643; p = 0.007). Logistic regression indicated that std(K{sup trans}) and SUVmean were significant predictors of short-term response (p < 0.07). Conclusion: Pretreatment multimodality imaging using {sup 1}H-MRS, DCE-MRI, and [{sup 18}F]FDG PET is feasible in HNSCC patients with nodal metastases. Additionally, combined DCE-MRI and [{sup 18}F]FDG PET parameters were predictive of short-term response to treatment.

  9. Play the MRI Game

    MedlinePLUS

    ... Teachers' Questionnaire MRI Play MRI the Magnetic Miracle Game About the game In the MRI imaging technique, strong magnets and ... last will in Paris. Play the Blood Typing Game Try to save some patients and learn about ...

  10. Leg MRI scan

    MedlinePLUS

    ... imaging - leg; Magnetic resonance imaging - lower extremity; MRI - ankle; Magnetic resonance imaging - ankle; MRI - femur; MRI - leg ... or bone scan Birth defects of the leg, ankle, or foot Bone pain and fever Broken bone ...

  11. Multivoxel 1H MR spectroscopy is superior to contrast-enhanced MRI for response assessment after anti-angiogenic treatment of orthotopic human glioma xenografts and provides handles for metabolic targeting

    PubMed Central

    Hamans, Bob; Navis, Anna Catharina; Wright, Alan; Wesseling, Pieter; Heerschap, Arend; Leenders, William

    2013-01-01

    Background Anti-angiogenic treatment of glioblastoma characteristically results in therapy resistance and tumor progression via diffuse infiltration. Monitoring tumor progression in these patients is thwarted because therapy results in tumor invisibility in contrast-enhanced (CE) MRI. To address this problem, we examined whether tumor progression could be monitored by metabolic mapping using 1H MR spectroscopic imaging (MRSI). Methods We treated groups of BALB/c nu/nu mice carrying different orthotopic diffuse-infiltrative glioblastoma xenografts with bevacizumab (antivascular endothelial growth factor [VEGF] antibody, n = 13), cabozantinib (combined VEGF receptor 2/c-Met tyrosine kinase inhibitor, n = 11), or placebo (n = 15) and compared CE-MRI with MRS-derived metabolic maps before, during, and after treatment. Metabolic maps and CE-MRIs were subsequently correlated to histology and immunohistochemistry. Results In vivo imaging of choline/n-acetyl aspartate ratios via multivoxel MRS is better able to evaluate response to therapy than CE-MRI. Lactate imaging revealed that diffuse infiltrative areas in glioblastoma xenografts did not present with excessive glycolysis. In contrast, glycolysis was observed in hypoxic areas in angiogenesis-dependent compact regions of glioma only, especially after anti-angiogenic treatment. Conclusion Our data present MRSI as a powerful and feasible approach that is superior to CE-MRI and may provide handles for optimizing treatment of glioma. Furthermore, we show that glycolysis is more prominent in hypoxic areas than in areas of diffuse infiltrative growth. The Warburg hypothesis of persisting glycolysis in tumors under normoxic conditions may thus not be valid for diffuse glioma. PMID:24158109

  12. Early post-bevacizumab progression on contrast-enhanced MRI as a prognostic marker for overall survival in recurrent glioblastoma: results from the ACRIN 6677/RTOG 0625 Central Reader Study

    PubMed Central

    Boxerman, Jerrold L.; Zhang, Zheng; Safriel, Yair; Larvie, Mykol; Snyder, Bradley S.; Jain, Rajan; Chi, T. Linda; Sorensen, A. Gregory; Gilbert, Mark R.; Barboriak, Daniel P.

    2013-01-01

    Background RTOG 0625/ACRIN 6677 is a multicenter, randomized, phase II trial of bevacizumab with irinotecan or temozolomide in recurrent glioblastoma (GBM). This study investigated whether early posttreatment progression on FLAIR or postcontrast MRI assessed by central reading predicts overall survival (OS). Methods Of 123 enrolled patients, 107 had baseline and at least 1 posttreatment MRI. Two central neuroradiologists serially measured bidimensional (2D) and volumetric (3D) enhancement on postcontrast T1-weighted images and volume of FLAIR hyperintensity. Progression status on all posttreatment MRIs was determined using Macdonald and RANO imaging threshold criteria, with a third neuroradiologist adjudicating discrepancies of both progression occurrence and timing. For each MRI pulse sequence, Kaplan-Meier survival estimates and log-rank test were used to compare OS between cases with or without radiologic progression. Results Radiologic progression occurred after 2 chemotherapy cycles (8 weeks) in 9 of 97 (9%), 9 of 73 (12%), and 11 of 98 (11%) 2D-T1, 3D-T1, and FLAIR cases, respectively, and 34 of 80 (43%), 21 of 58 (36%), and 37 of 79 (47%) corresponding cases after 4 cycles (16 weeks). Median OS among patients progressing at 8 or 16 weeks was significantly less than that among nonprogressors, as determined on 2D-T1 (114 vs 278 days and 214 vs 426 days, respectively; P < .0001 for both) and 3D-T1 (117 vs 306 days [P < .0001] and 223 vs 448 days [P = .0003], respectively) but not on FLAIR (201 vs 276 days [P = .38] and 303 vs 321 days [P = .13], respectively). Conclusion Early progression on 2D-T1 and 3D-T1, but not FLAIR MRI, after 8 and 16 weeks of antivascular endothelial growth factor therapy has highly significant prognostic value for OS in recurrent GBM. PMID:23788270

  13. Theoretical considerations in measurement of time discrepancies between input and myocardial time-signal intensity curves in estimates of regional myocardial perfusion with first-pass contrast-enhanced MRI.

    PubMed

    Natsume, Takahiro; Ishida, Masaki; Kitagawa, Kakuya; Nagata, Motonori; Sakuma, Hajime; Ichihara, Takashi

    2015-11-01

    The purpose of this study was to develop a method to determine time discrepancies between input and myocardial time-signal intensity (TSI) curves for accurate estimation of myocardial perfusion with first-pass contrast-enhanced MRI. Estimation of myocardial perfusion with contrast-enhanced MRI using kinetic models requires faithful recording of contrast content in the blood and myocardium. Typically, the arterial input function (AIF) is obtained by setting a region of interest in the left ventricular cavity. However, there is a small delay between the AIF and the myocardial curves, and such time discrepancies can lead to errors in flow estimation using Patlak plot analysis. In this study, the time discrepancies between the arterial TSI curve and the myocardial tissue TSI curve were estimated based on the compartment model. In the early phase after the arrival of the contrast agent in the myocardium, the relationship between rate constant K1 and the concentrations of Gd-DTPA contrast agent in the myocardium and arterial blood (LV blood) can be described by the equation K1={dCmyo(tpeak)/dt}/Ca(tpeak), where Cmyo(t) and Ca(t) are the relative concentrations of Gd-DTPA contrast agent in the myocardium and in the LV blood, respectively, and tpeak is the time corresponding to the peak of Ca(t). In the ideal case, the time corresponding to the maximum upslope of Cmyo(t), tmax, is equal to tpeak. In practice, however, there is a small difference in the arrival times of the contrast agent into the LV and into the myocardium. This difference was estimated to correspond to the difference between tpeak and tmax. The magnitudes of such time discrepancies and the effectiveness of the correction for these time discrepancies were measured in 18 subjects who underwent myocardial perfusion MRI under rest and stress conditions. The effects of the time discrepancies could be corrected effectively in the myocardial perfusion estimates. PMID:26117690

  14. A case report of pseudoprogression followed by complete remission after proton-beam irradiation for a low-grade glioma in a teenager: the value of dynamic contrast-enhanced MRI.

    PubMed

    Meyzer, Candice; Dhermain, Frdric; Ducreux, Denis; Habrand, Jean-Louis; Varlet, Pascale; Sainte-Rose, Christian; Dufour, Christelle; Grill, Jacques

    2010-01-01

    A fourteen years-old boy was treated post-operatively with proton therapy for a recurrent low-grade oligodendroglioma located in the tectal region. Six months after the end of irradiation (RT), a new enhancing lesion appeared within the radiation fields. To differentiate disease progression from radiation-induced changes, dynamic susceptibility contrast-enhanced (DSCE) MRI was used with a T2* sequence to study perfusion and permeability characteristics simultaneously. Typically, the lesion showed hypoperfusion and hyperpermeability compared to the controlateral normal brain. Without additional treatment but a short course of steroids, the image disappeared over a six months period allowing us to conclude for a pseudo-progression. The patient is alive in complete remission more than 2 years post-RT. PMID:20132555

  15. Feasibility of simultaneous whole-brain imaging on an integrated PET-MRI system using an enhanced 2-point Dixon attenuation correction method

    PubMed Central

    Anazodo, Udunna C.; Thiessen, Jonathan D.; Ssali, Tracy; Mandel, Jonathan; Gnther, Matthias; Butler, John; Pavlosky, William; Prato, Frank S.; Thompson, R. Terry; St. Lawrence, Keith S.

    2015-01-01

    Purpose: To evaluate a potential approach for improved attenuation correction (AC) of PET in simultaneous PET and MRI brain imaging, a straightforward approach that adds bone information missing on Dixon AC was explored. Methods: Bone information derived from individual T1-weighted MRI data using segmentation tools in SPM8, were added to the standard Dixon AC map. Percent relative difference between PET reconstructed with Dixon+bone and with Dixon AC maps were compared across brain regions of 13 oncology patients. The clinical potential of the improved Dixon AC was investigated by comparing relative perfusion (rCBF) measured with arterial spin labeling to relative glucose uptake (rPETdxbone) measured simultaneously with 18F-flurodexoyglucose in several regions across the brain. Results: A gradual increase in PET signal from center to the edge of the brain was observed in PET reconstructed with Dixon+bone. A 520% reduction in regional PET signals were observed in data corrected with standard Dixon AC maps. These regional underestimations of PET were either reduced or removed when Dixon+bone AC was applied. The mean relative correlation coefficient between rCBF and rPETdxbone was r = 0.53 (p < 0.001). Marked regional variations in rCBF-to-rPET correlation were observed, with the highest associations in the caudate and cingulate and the lowest in limbic structures. All findings were well matched to observations from previous studies conducted with PET data reconstructed with computed tomography derived AC maps. Conclusion: Adding bone information derived from T1-weighted MRI to Dixon AC maps can improve underestimation of PET activity in hybrid PET-MRI neuroimaging. PMID:25601825

  16. Comparison of the hepatic perfusion index measured with gadolinium-enhanced volumetric MRI in controls and in patients with colorectal cancer.

    PubMed

    Totman, J J; O'gorman, R L; Kane, P A; Karani, J B

    2005-02-01

    The aim of the study was to adapt the methodology established for dynamic CT measurements of the hepatic perfusion index (HPI) to MRI, and to assess the potential role of MRI measurements of the HPI in detecting regional alterations in liver perfusion between patients with colorectal liver metastases and normal controls. The HPI was evaluated from serial T(1) volume acquisitions acquired over the course of a Gd-DTPA bolus injection. Time-course data from regions of interest in the liver, spleen and aorta were used to calculate the HPI; and HPI data from control subjects were compared with data from patients with known colorectal metastases. Significant differences were found between the relative portal perfusion and hepatic perfusion indices calculated for the patient and control groups (p<0.005). These results suggest that hepatic perfusion indices can be derived using MRI-based methods, and that these perfusion indices are sensitive to differences in liver perfusion associated with established metastatic liver disease on imaging. This technique may contribute to the early detection of liver metastases, allowing early surgical intervention and improved patient survival. PMID:15681320

  17. Neurosarcoidosis: evaluation with MRI.

    PubMed

    Pickuth, D; Heywang-Köbrunner, S H

    2000-09-01

    Clinical studies report a rate of 5% and autopsy results a rate of 25% of brain involvement in sarcoidosis. The aim of this study was to evaluate the role of magnetic resonance imaging (MRI) in the diagnosis of patients with neurosarcoidosis. The MRI brain scans of 22 patients with sarcoidosis were retrospectively reviewed, along with the clinical information that was provided in the request form. All patients had signs and symptoms referable to the head and were examined with gadolinium enhancement. Cranial (facial) nerve paralysis was the most common clinical manifestation identified in 10 patients. A wide spectrum of MR findings was noted: Periventricular and white matter lesions on T2W spin echo images, mimicking multiple sclerosis (46%); multiple supratentorial and infratentorial brain lesions, mimicking metastases (36%); solitary intraaxial mass, mimicking high grade astrocytoma (9%); solitary extraaxial mass, mimicking meningioma (5%); leptomeningeal enhancement (36%). These findings are not specific for sarcoidosis and one must consider appropriate clinical circumstances in arriving at the correct diagnosis. In selected cases with isolated brain involvement, meningeal or cerebral biopsy may be required. PMID:11104966

  18. Competitive advantage of PET/MRI.

    PubMed

    Jadvar, Hossein; Colletti, Patrick M

    2014-01-01

    Multimodality imaging has made great strides in the imaging evaluation of patients with a variety of diseases. Positron emission tomography/computed tomography (PET/CT) is now established as the imaging modality of choice in many clinical conditions, particularly in oncology. While the initial development of combined PET/magnetic resonance imaging (PET/MRI) was in the preclinical arena, hybrid PET/MR scanners are now available for clinical use. PET/MRI combines the unique features of MRI including excellent soft tissue contrast, diffusion-weighted imaging, dynamic contrast-enhanced imaging, fMRI and other specialized sequences as well as MR spectroscopy with the quantitative physiologic information that is provided by PET. Most evidence for the potential clinical utility of PET/MRI is based on studies performed with side-by-side comparison or software-fused MRI and PET images. Data on distinctive utility of hybrid PET/MRI are rapidly emerging. There are potential competitive advantages of PET/MRI over PET/CT. In general, PET/MRI may be preferred over PET/CT where the unique features of MRI provide more robust imaging evaluation in certain clinical settings. The exact role and potential utility of simultaneous data acquisition in specific research and clinical settings will need to be defined. It may be that simultaneous PET/MRI will be best suited for clinical situations that are disease-specific, organ-specific, related to diseases of the children or in those patients undergoing repeated imaging for whom cumulative radiation dose must be kept as low as reasonably achievable. PET/MRI also offers interesting opportunities for use of dual modality probes. Upon clear definition of clinical utility, other important and practical issues related to business operational model, clinical workflow and reimbursement will also be resolved. PMID:23791129

  19. Computer-aided detection of brain tumor invasion using multiparametric MRI

    PubMed Central

    Jensen, Todd R.; Schmainda, Kathleen M.

    2010-01-01

    Purpose To determine the potential of using a computer-aided detection method to intelligently distinguish peritumoral edema alone from peritumor edema consisting of tumor using a combination of high-resolution morphological and physiological magnetic resonance imaging (MRI) techniques available on most clinical MRI scanners. Materials and Methods This retrospective study consisted of patients with two types of primary brain tumors: meningiomas (n=7) and glioblastomas (n=11). Meningiomas are typically benign and have a clear delineation of tumor and edema. Glioblastomas are known to invade outside the contrast-enhancing area. Four classifiers of differing designs were trained using morphological, diffusion-weighted, and perfusion-weighted features derived from MRI to discriminate tumor and edema, tested on edematous regions surrounding tumors, and assessed for their ability to detect nonenhancing tumor invasion. Results The four classifiers provided similar measures of accuracy when applied to the training and testing data. Each classifier was able to identify areas of non-enhancing tumor invasion supported with adjunct images or follow-up studies. Conclusion The combination of features derived from morphological and physiological imaging techniques contains the information necessary for computer-aided detection of tumor invasion and allows for the identification of tumor invasion not previously visualized on morphological, diffusion-weighted, and perfusion-weighted images and maps. Further validation of this approach requires obtaining spatially co-registered tissue samples in a study with a larger sample size. PMID:19711398

  20. High-temporospatial-resolution dynamic contrast-enhanced (DCE) wrist MRI with variable-density pseudo-random circular Cartesian undersampling (CIRCUS) acquisition: evaluation of perfusion in rheumatoid arthritis patients.

    PubMed

    Liu, Jing; Pedoia, Valentina; Heilmeier, Ursula; Ku, Eric; Su, Favian; Khanna, Sameer; Imboden, John; Graf, Jonathan; Link, Thomas; Li, Xiaojuan

    2016-01-01

    This study is to evaluate highly accelerated three-dimensional (3D) dynamic contrast-enhanced (DCE) wrist MRI for assessment of perfusion in rheumatoid arthritis (RA) patients. A pseudo-random variable-density undersampling strategy, circular Cartesian undersampling (CIRCUS), was combined with k-t SPARSE-SENSE reconstruction to achieve a highly accelerated 3D DCE wrist MRI. Two healthy volunteers and 10 RA patients were studied. Two patients were on methotrexate (MTX) only (Group I) and the other eight were treated with a combination therapy of MTX and anti-tumor necrosis factor (TNF) therapy (Group II). Patients were scanned at baseline and 3?month follow-up. DCE MR images were used to evaluate perfusion in synovitis and bone marrow edema pattern in the RA wrist joints. A series of perfusion parameters was derived and compared with clinical disease activity scores of 28 joints (DAS28). 3D DCE wrist MR images were obtained with a spatial resolution of 0.3??0.3??1.5?mm(3) and temporal resolution of 5?s (with an acceleration factor of 20). The derived perfusion parameters, most notably transition time (dT) of synovitis, showed significant negative correlations with DAS28-ESR (r?=?-0.80, p?MRI with improved temporospatial resolution has been achieved in RA patients and provides accurate assessment of neovascularization and perfusion in RA joints, showing promise as a potential tool for evaluating treatment responses. Copyright 2015 John Wiley & Sons, Ltd. PMID:26608949

  1. RESTRICTION FRAGMENT LENGTH POLYMORPHISMS DISTINGUISH ECTOMYCORRHIZAL FUNGI

    EPA Science Inventory

    Basidiomycetous fungi, two saprophytes and three mycorrhizal, were used to assess the specificity of DNA hybridization for distinguishing genera from one another. nterspecific comparisons were done with several isolates of mycorrhizal fungi, Laccaria bicolor and L. laccata, colle...

  2. Accurate determination of bloodbrain barrier permeability using dynamic contrast-enhanced T1-weighted MRI: a simulation and in vivo study on healthy subjects and multiple sclerosis patients

    PubMed Central

    Cramer, Stig P; Larsson, Henrik B W

    2014-01-01

    Dynamic contrast-enhanced magnetic resonance imaging (DCEMRI) is increasingly used to estimate permeability in situations with subtle bloodbrain barrier (BBB) leakage. However, the method's ability to differentiate such low values from zero is unknown, and no consensus exists on optimal selection of total measurement duration, temporal resolution, and modeling approach under varying physiologic circumstances. To estimate accuracy and precision of the DCEMRI method we generated simulated data using a two-compartment model and progressively down-sampled and truncated the data to mimic low temporal resolution and short total measurement duration. Model fit was performed with the Patlak, the extended Tofts, and the Tikhonov two-compartment (Tik-2CM) models. Overall, 17 healthy controls were scanned to obtain in vivo data. Long total measurement duration (15 minutes) and high temporal resolution (1.25 seconds) greatly improved accuracy and precision for all three models, enabling us to differentiate values of permeability as low as 0.1?ml/100?g/min from zero. The Patlak model yielded highest accuracy and precision for permeability values <0.3?ml/100?g/min, but for higher values the Tik-2CM performed best. Our results emphasize the importance of optimal parameter setup and model selection when characterizing low BBB permeability. PMID:25074746

  3. Post-treatment with cocaine- and amphetamine-regulated transcript enhances infarct resolution, reinnervation, and angiogenesis in stroke rats - an MRI study.

    PubMed

    Liu, H-S; Shen, H; Luo, Y; Hoffer, B J; Wang, Y; Yang, Y

    2016-03-01

    Recent studies have shown that post-treatment with cocaine- and amphetamine-regulated transcript (CART) has neuroregenerative effects in animal models of stroke. The purpose of this study was to characterize CART-mediated neuronal and vascular repairments using non-invasive MRI techniques. Adult male rats were subjected to a 90 min middle cerebral artery occlusion (MCAo). Animals were separated into two groups with similar infarction sizes, measured by T2 -weighted MRI on Day 2 after MCAo, and were treated with CART or vehicle intranasally from Day 3 to Day 12. Diffusion tensor imaging was used to examine changes in plasticity of white matter elements. Susceptibility-weighted imaging (SWI) was used to measure angiogenesis. Post-treatment with CART significantly increased fractional anisotropy (FA) in lesioned cortex on Days 10 and 25 post stroke. A significant correlation between the behavioral recovery in body asymmetry and the change in FA was shown, suggesting that behavioral recovery was associated with reinnervation to the lesioned hemisphere. CART also increased the intensity of SWI and the immunoreactivity of the vascular marker alpha-smooth muscle actin in lesioned cortex. Together, our data support a non-invasive treatment strategy for stroke through angiogenesis and reinnervation by CART. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26915794

  4. Association between bilateral asymmetry of kinetic features computed from the DCE-MRI images and breast cancer

    NASA Astrophysics Data System (ADS)

    Yang, Qian; Li, Lihua; Zhang, Juan; Zhang, Chengjie; Zheng, Bin

    2013-03-01

    Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) of breast yields high sensitivity but relatively lower specificity. To improve diagnostic accuracy of DCE-MRI, we investigated the association between bilateral asymmetry of kinetic features computed from the left and right breasts and breast cancer detection with the hypothesis that due to the growth of angiogenesis associated with malignant lesions, the average dynamic contrast enhancement computed from the breasts depicting malignant lesions should be higher than negative or benign breasts. To test this hypothesis, we assembled a database involving 130 DCE-MRI examinations including 81 malignant and 49 benign cases. We developed a computerized scheme that automatically segments breast areas depicted on MR images and computes kinetic features related to the bilateral asymmetry of contrast enhancement ratio between two breasts. An artificial neural network (ANN) was then used to classify between malignant and benign cases. To identify the optimal approach to compute the bilateral kinetic feature asymmetry, we tested 4 different thresholds to select the enhanced pixels (voxels) from DCE-MRI images and compute the kinetic features. Using the optimal threshold, the ANN had a classification performance measured by the area under the ROC curve of AUC=0.79+/-0.04. The positive and negative predictive values were 0.75 and 0.67, respectively. The study suggested that the bilateral asymmetry of kinetic features or contrast enhancement of breast background tissue could provide valuable supplementary information to distinguish between the malignant and benign cases, which can be fused into existing computer-aided detection schemes to improve classification performance.

  5. Intra voxel analysis in MRI

    NASA Astrophysics Data System (ADS)

    Ambrosanio, Michele; Baselice, Fabio; Ferraioli, Giampaolo; Pascazio, Vito

    2014-03-01

    A new application of Compressive Sensing (CS) in Magnetic Resonance Imaging (MRI) field is presented. In particular, first results of the Intra Voxel Analysis (IVA) technique are reported. The idea is to exploit CS peculiarities in order to distinguish different contributions inside the same resolution cell, instead of reconstructing images from not fully sampled k-space acquisition. Applied to MRI field, this means the possibility of estimating the presence of different tissues inside the same voxel, i.e. in one pixel of the obtained image. In other words, the method is the first attempt, as far as we know, of achieving Spectroscopy-like results starting from each pixel of MR images. In particular, tissues are distinguished each others by evaluating their spin-spin relaxation times. Within this manuscript, first results on clinical dataset, in particular a phantom made by aqueous solution and oil and an occipital brain lesion corresponding to a metastatic breast cancer nodule, are reported. Considering the phantom dataset, in particular focusing on the slice where the separation between water and oil occurs, the methodology is able to distinguish the two components with different spin-spin relaxation times. With respect to clinical dataset,focusing on a voxel of the lesion area, the approach is able to detect the presence of two tissues, namely the healthy and the cancer related ones, while in other location outside the lesion only the healthy tissue is detected. Of course, these are the first results of the proposed methodology, further studies on different types of clinical datasets are required in order to widely validate the approach. Although few datasets have been considered, results seem both interesting and promising.

  6. Engineering novel detectors and sensors for MRI.

    PubMed

    Qian, Chunqi; Zabow, Gary; Koretsky, Alan

    2013-04-01

    Increasing detection sensitivity and image contrast have always been major topics of research in MRI. In this perspective, we summarize two engineering approaches to make detectors and sensors that have potential to extend the capability of MRI. The first approach is to integrate miniaturized detectors with a wireless powered parametric amplifier to enhance the detection sensitivity of remotely coupled detectors. The second approach is to microfabricate contrast agents with encoded multispectral frequency shifts, whose properties can be specified and fine-tuned by geometry. These two complementary approaches will benefit from the rapid development in nanotechnology and microfabrication which should enable new opportunities for MRI. PMID:23245489

  7. Polycatechol Nanoparticle MRI Contrast Agents.

    PubMed

    Li, Yiwen; Huang, Yuran; Wang, Zhao; Carniato, Fabio; Xie, Yijun; Patterson, Joseph P; Thompson, Matthew P; Andolina, Christopher M; Ditri, Treffly B; Millstone, Jill E; Figueroa, Joshua S; Rinehart, Jeffrey D; Scadeng, Miriam; Botta, Mauro; Gianneschi, Nathan C

    2016-02-01

    Amphiphilic triblock copolymers containing Fe(III) -catecholate complexes formulated as spherical- or cylindrical-shaped micellar nanoparticles (SMN and CMN, respectively) are described as new T 1 -weighted agents with high relaxivity, low cytotoxicity, and long-term stability in biological fluids. Relaxivities of both SMN and CMN exceed those of established gadolinium chelates across a wide range of magnetic field strengths. Interestingly, shape-dependent behavior is observed in terms of the particles' interactions with HeLa cells, with CMN exhibiting enhanced uptake and contrast via magnetic resonance imaging (MRI) compared with SMN. These results suggest that control over soft nanoparticle shape will provide an avenue for optimization of particle-based contrast agents as biodiagnostics. The polycatechol nanoparticles are proposed as suitable for preclinical investigations into their viability as gadolinium-free, safe, and effective imaging agents for MRI contrast enhancement. PMID:26681255

  8. Magnetic Resonance Imaging (MRI)

    MedlinePLUS

    ... radiology centers use what are called "open" MRI machines. They have larger openings and are helpful for ... specially trained technician (or "tech") operates the MRI machine. He or she may ask if you have ...

  9. MRI (Magnetic Resonance Imaging)

    MedlinePLUS

    ... IV in the arm. MRI Research Programs at FDA Magnetic Resonance Imaging (MRI) Safety Electromagnetic Modeling Related ... Resonance Imaging Equipment in Clinical Use (March 2015) FDA/CDER: Information on Gadolinium-Based Contrast Agents More ...

  10. MRI (Magnetic Resonance Imaging)

    MedlinePLUS

    ... a patients body. (In open-MRI devices, permanent magnets are used.) Radio waves are sent from and ... before performing or undergoing an MRI scan: The magnet may cause pacemakers, artificial limbs, and other implanted ...

  11. High-Speed Real-Time Resting-State fMRI Using Multi-Slab Echo-Volumar Imaging

    PubMed Central

    Posse, Stefan; Ackley, Elena; Mutihac, Radu; Zhang, Tongsheng; Hummatov, Ruslan; Akhtari, Massoud; Chohan, Muhammad; Fisch, Bruce; Yonas, Howard

    2013-01-01

    We recently demonstrated that ultra-high-speed real-time fMRI using multi-slab echo-volumar imaging (MEVI) significantly increases sensitivity for mapping task-related activation and resting-state networks (RSNs) compared to echo-planar imaging (Posse et al., 2012). In the present study we characterize the sensitivity of MEVI for mapping RSN connectivity dynamics, comparing independent component analysis (ICA) and a novel seed-based connectivity analysis (SBCA) that combines sliding-window correlation analysis with meta-statistics. This SBCA approach is shown to minimize the effects of confounds, such as movement, and CSF and white matter signal changes, and enables real-time monitoring of RSN dynamics at time scales of tens of seconds. We demonstrate highly sensitive mapping of eloquent cortex in the vicinity of brain tumors and arterio-venous malformations, and detection of abnormal resting-state connectivity in epilepsy. In patients with motor impairment, resting-state fMRI provided focal localization of sensorimotor cortex compared with more diffuse activation in task-based fMRI. The fast acquisition speed of MEVI enabled segregation of cardiac-related signal pulsation using ICA, which revealed distinct regional differences in pulsation amplitude and waveform, elevated signal pulsation in patients with arterio-venous malformations and a trend toward reduced pulsatility in gray matter of patients compared with healthy controls. Mapping cardiac pulsation in cortical gray matter may carry important functional information that distinguishes healthy from diseased tissue vasculature. This novel fMRI methodology is particularly promising for mapping eloquent cortex in patients with neurological disease, having variable degree of cooperation in task-based fMRI. In conclusion, ultra-high-real-time speed fMRI enhances the sensitivity of mapping the dynamics of resting-state connectivity and cerebro-vascular pulsatility for clinical and neuroscience research applications. PMID:23986677

  12. Distinguishing grade I meningioma from higher grade meningiomas without biopsy

    PubMed Central

    Varlotto, John; Flickinger, John; Pavelic, Martin T.; Specht, Charles S.; Sheehan, Jonas M.; Timek, Dana T.; Glantz, Michael J.; Sogge, Steven; Dimaio, Christopher; Moser, Richard; Yunus, Shakeeb; Fitzgerald, Thomas J.; Upadhyay, Urvashi; Rava, Paul; Tangel, Matthew; Yao, Aaron; Kanekar, Sangam

    2015-01-01

    Background Many meningiomas are identified by imaging and followed, with an assumption that they are WHO Grade I tumors. The purpose of our investigation is to find clinical or imaging predictors of WHO Grade II/III tumors to distinguish them from Grade I meningiomas. Methods Patients with a pathologic diagnosis of meningioma from 2002–2009 were included if they had pre-operative MRI studies and pathology for review. A Neuro-Pathologist reviewed and classified all tumors by WHO 2007. All Brain MRI imaging was reviewed by a Neuro-radiologist. Pathology and Radiology reviews were blinded from each other and clinical course. Recursive partitioning was used to create predictive models for identifying meningioma grades. Results Factors significantly correlating with a diagnosis of WHO Grade II-III tumors in univariate analysis: prior CVA (p = 0.005), CABG (p = 0.010), paresis (p = 0.008), vascularity index = 4/4: (p = 0.009), convexity vs other (p = 0.014), metabolic syndrome (p = 0.025), non-skull base (p = 0.041) and non-postmenopausal female (p = 0.045). Recursive partitioning analysis identified four categories: 1. prior CVA, 2. vascular index (vi) = 4 (no CVA), 3. premenopausal or male, vi < 4, no CVA. 4. Postmenopausal, vi < 4, no CVA with corresponding rates of 73, 54, 35 and 10% of being Grade II-III meningiomas. Conclusions Meningioma patients with prior CVA and those grade 4/4 vascularity are the most likely to have WHO Grade II-III tumors while post-menopausal women without these features are the most likely to have Grade I meningiomas. Further study of the associations of clinical and imaging factors with grade and clinical behavior are needed to better predict behavior of these tumors without biopsy. PMID:26472106

  13. Outcome Classification of Preschool Children with Autism Spectrum Disorders Using Mri Brain Measures.

    ERIC Educational Resources Information Center

    Akshoomoff, Natacha; Lord, Catherine; Lincoln, Alan J.; Courchesne, Rachel Y.; Carper, Ruth A.; Townsend, Jeanne; Courchesne, Eric

    2004-01-01

    Objective: To test the hypothesis that a combination of magnetic resonance imaging (MRI) brain measures obtained during early childhood distinguish children with autism spectrum disorders (ASD) from typically developing children and is associated with functional outcome. Method: Quantitative MRI technology was used to measure gray and white matter…

  14. [Leiomyoma of the prostate. Appearance on the MRI. Apropos of 2 cases].

    PubMed

    Gevenois, P A; Gysels, M; Corbusier, A; Van Regemorter, G; Depierreux, M; Struyven, J

    1987-10-01

    Two cases of leiomyoma of the prostate are reported. They are the first studies by M.R.I. Based on the results of M.R.I. of these lesions, differential diagnosis with malignant processes of the prostate is discussed. Associated with a benign prostatic hypertrophy, the leiomyoma must be distinguished from additional neoplasm. PMID:2448453

  15. Outcome Classification of Preschool Children with Autism Spectrum Disorders Using Mri Brain Measures.

    ERIC Educational Resources Information Center

    Akshoomoff, Natacha; Lord, Catherine; Lincoln, Alan J.; Courchesne, Rachel Y.; Carper, Ruth A.; Townsend, Jeanne; Courchesne, Eric

    2004-01-01

    Objective: To test the hypothesis that a combination of magnetic resonance imaging (MRI) brain measures obtained during early childhood distinguish children with autism spectrum disorders (ASD) from typically developing children and is associated with functional outcome. Method: Quantitative MRI technology was used to measure gray and white matter

  16. Beyond Benford's Law: Distinguishing Noise from Chaos

    PubMed Central

    Li, Qinglei; Fu, Zuntao; Yuan, Naiming

    2015-01-01

    Determinism and randomness are two inherent aspects of all physical processes. Time series from chaotic systems share several features identical with those generated from stochastic processes, which makes them almost undistinguishable. In this paper, a new method based on Benford's law is designed in order to distinguish noise from chaos by only information from the first digit of considered series. By applying this method to discrete data, we confirm that chaotic data indeed can be distinguished from noise data, quantitatively and clearly. PMID:26030809

  17. Stanislas Dehaene: Award for Distinguished Scientific Contributions.

    PubMed

    2015-11-01

    The APA Awards for Distinguished Scientific Contributions are presented to persons who, in the opinion of the Committee on Scientific Awards, have made distinguished theoretical or empirical contributions to basic research in psychology. One of the 2015 award winners is Stanislas Dehaene, who received this award for "outstanding empirical and theoretical contributions to not just one but three fields that are central to the enterprises of psychology and cognitive neuroscience." Dehaene's award citation, biography, and a selected bibliography are presented here. (PsycINFO Database Record PMID:26618941

  18. Michael Tomasello: Award for Distinguished Scientific Contributions.

    PubMed

    2015-11-01

    The APA Awards for Distinguished Scientific Contributions are presented to persons who, in the opinion of the Committee on Scientific Awards, have made distinguished theoretical or empirical contributions to basic research in psychology. One of the 2015 award winners is Michael Tomasello, who received this award for "outstanding empirical and theoretical contributions to understanding what makes the human mind unique. Michael Tomasello's pioneering research on the origins of social cognition has led to revolutionary insights in both developmental psychology and primate cognition." Tomasello's award citation, biography, and a selected bibliography are presented here. (PsycINFO Database Record PMID:26618943

  19. The Attentional Field Revealed by Single-Voxel Modeling of fMRI Time Courses

    PubMed Central

    DeYoe, Edgar A.

    2015-01-01

    The spatial topography of visual attention is a distinguishing and critical feature of many theoretical models of visuospatial attention. Previous fMRI-based measurements of the topography of attention have typically been too crude to adequately test the predictions of different competing models. This study demonstrates a new technique to make detailed measurements of the topography of visuospatial attention from single-voxel, fMRI time courses. Briefly, this technique involves first estimating a voxel's population receptive field (pRF) and then drifting attention through the pRF such that the modulation of the voxel's fMRI time course reflects the spatial topography of attention. The topography of the attentional field (AF) is then estimated using a time-course modeling procedure. Notably, we are able to make these measurements in many visual areas including smaller, higher order areas, thus enabling a more comprehensive comparison of attentional mechanisms throughout the full hierarchy of human visual cortex. Using this technique, we show that the AF scales with eccentricity and varies across visual areas. We also show that voxels in multiple visual areas exhibit suppressive attentional effects that are well modeled by an AF having an enhancing Gaussian center with a suppressive surround. These findings provide extensive, quantitative neurophysiological data for use in modeling the psychological effects of visuospatial attention. PMID:25810532

  20. MRI mimics of multiple sclerosis.

    PubMed

    Aliaga, Esther Sánchez; Barkhof, Frederik

    2014-01-01

    Diagnosis of multiple sclerosis (MS) is based on the demonstration of dissemination of lesions in space (DIS) and in time (DIT), as well as on the exclusion of an alternative neurologic disorder. As a paraclinical tool brain and/or spinal cord magnetic resonance imaging (MRI), showing typical lesion morphology, characteristic distribution of lesions, or involvement or specific anatomic structures, can support the diagnosis of MS. But from an imaging perspective a considerable amount of inherited and acquired disorders may manifest with radiologic evidence of DIT, DIS, or both. Hypoxic-ischemic vasculopathy, specially small-vessel disease, inflammatory disorders, vasculitis, and non-MS idiopathic inflammatory disorders, as well as some toxic, metabolic, and infectious disorders, may present mimicking MS on MR examinations and should be included in the differential diagnosis of MS-like lesions. Careful evaluation of associated findings on MRI, the so-called MRI red flags, such as the presence of infarcts, microbleeds, meningeal enhancement, and calcifications among others, are very helpful in suggesting a diagnosis other than MS. Complement MRI findings to patient's history, demographics, and serologic findings are crucial to achieve the correct diagnosis. We will review the most frequent radiologic appearance and differential features from the most frequent MS mimickers. PMID:24507523

  1. Identification of High-Risk Plaques by MRI and Fluorescence Imaging in a Rabbit Model of Atherothrombosis

    PubMed Central

    Hua, Ning; Baik, Fred; Pham, Tuan; Phinikaridou, Alkystis; Giordano, Nick; Friedman, Beth; Whitney, Michael; Nguyen, Quyen T.; Tsien, Roger Y.; Hamilton, James A.

    2015-01-01

    Introduction The detection of atherosclerotic plaques at risk for disruption will be greatly enhanced by molecular probes that target vessel wall biomarkers. Here, we test if fluorescently-labeled Activatable Cell Penetrating Peptides (ACPPs) could differentiate stable plaques from vulnerable plaques that disrupt, forming a luminal thrombus. Additionally, we test the efficacy of a combined ACPP and MRI technique for identifying plaques at high risk of rupture. Methods and Results In an atherothrombotic rabbit model, disrupted plaques were identified with in vivo MRI and co-registered in the same rabbit aorta with the in vivo uptake of ACPPs, cleaved by matrix metalloproteinases (MMPs) or thrombin. ACPP uptake, mapped ex vivo in whole aortas, was higher in disrupted compared to non-disrupted plaques. Specifically, disrupted plaques demonstrated a 4.5~5.0 fold increase in fluorescence enhancement, while non-disrupted plaques showed only a 2.2~2.5 fold signal increase. Receiver operating characteristic (ROC) analysis indicates that both ACPPs (MMP and thrombin) show high specificity (84.2% and 83.2%) and sensitivity (80.0% and 85.7%) in detecting disrupted plaques. The detection power of ACPPs was improved when combined with the MRI derived measure, outward remodeling ratio. Conclusions Our targeted fluorescence ACPP probes distinguished disrupted plaques from stable plaques with high sensitivity and specificity. The combination of anatomic, MRI-derived predictors for disruption and ACPP uptake can further improve the power for identification of high-risk plaques and suggests future development of ACPPs with molecular MRI as a readout. PMID:26448434

  2. Distinguishing Disability: Parents, Privilege, and Special Education

    ERIC Educational Resources Information Center

    Ong-Dean, Colin

    2009-01-01

    Students in special education programs can have widely divergent experiences. For some, special education amounts to a dumping ground where schools unload their problem students, while for others, it provides access to services and accommodations that drastically improve chances of succeeding in school and beyond. "Distinguishing Disability"

  3. Characteristics of Distinguished Programs of Agricultural Education

    ERIC Educational Resources Information Center

    Birkenholz, Robert J.; Simonsen, Jon C.

    2011-01-01

    Academic program rankings are highly anticipated by many university administrators, faculty, and alumni. This study analyzed the perceptions of agricultural education departmental contact persons to identify esteemed post-secondary agricultural education programs and the distinguishing characteristics of each program. The ten most distinguished…

  4. Children Distinguish between Positive Pride and Hubris

    ERIC Educational Resources Information Center

    Nelson, Nicole L.; Russell, James A.

    2015-01-01

    Adults distinguish expressions of hubris from those of positive pride. To determine whether children (N = 183; 78-198 months old) make a similar distinction, we asked them to attribute emotion labels and a variety of social characteristics to dynamic expressions intended to convey hubris and positive pride. Like adults, children attributed

  5. Local distinguishability of generic unentangled orthonormal bases

    NASA Astrophysics Data System (ADS)

    Lebl, Jiří; Shakeel, Asif; Wallach, Nolan

    2016-01-01

    An orthonormal basis consisting of unentangled (pure tensor) elements in a tensor product of Hilbert spaces is an unentangled orthonormal basis (UOB). In general, for n qubits, we prove that in its natural structure as a real variety, the space of UOB is a bouquet of products of Riemann spheres parametrized by a class of edge colorings of hypercubes. Its irreducible components of maximum dimension are products of 2n-1 two spheres. Using a theorem of Walgate and Hardy, we observe that the UOB whose elements are distinguishable by local operations and classical communication (called locally distinguishable or LOCC distinguishable UOB) are exactly those in the maximum dimensional components. Bennett et al. [Phys. Rev. A 59, 1070 (1999)., 10.1103/PhysRevA.59.1070], in their in-depth study of quantum nonlocality without entanglement, include a specific three-qubit example UOB which is not LOCC distinguishable; we construct certain generalized counterparts of this UOB in n qubits.

  6. Entropy of Mixing of Distinguishable Particles

    ERIC Educational Resources Information Center

    Kozliak, Evguenii I.

    2014-01-01

    The molar entropy of mixing yields values that depend only on the number of mixing components rather than on their chemical nature. To explain this phenomenon using the logic of chemistry, this article considers mixing of distinguishable particles, thus complementing the well-known approach developed for nondistinguishable particles, for example,…

  7. The Humanity of English. 1972 Distinguished Lectures.

    ERIC Educational Resources Information Center

    National Council of Teachers of English, Urbana, IL.

    This is a collection of lectures by distinguished members of the English profession who were invited to lecture to schools located far from large urban and cultural centers. Included are papers by: John H. Fisher, "Truth Versus Beauty: An Inquiry into the Function of Language and Literature in an Articulate Society"; Walter Loban, "The Green

  8. Entropy of Mixing of Distinguishable Particles

    ERIC Educational Resources Information Center

    Kozliak, Evguenii I.

    2014-01-01

    The molar entropy of mixing yields values that depend only on the number of mixing components rather than on their chemical nature. To explain this phenomenon using the logic of chemistry, this article considers mixing of distinguishable particles, thus complementing the well-known approach developed for nondistinguishable particles, for example,

  9. 10 CFR 1002.22 - Use of distinguishing flag.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Use of distinguishing flag. 1002.22 Section 1002.22 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) OFFICIAL SEAL AND DISTINGUISHING FLAG Distinguishing Flag § 1002.22 Use of distinguishing flag. (a) DOE distinguishing flags may be used only: (1) In the offices of...

  10. MRI in breast cancer therapy monitoring

    PubMed Central

    McLaughlin, Rebekah; Hylton, Nola

    2015-01-01

    Breast MRI has several roles in the clinical management of breast cancer, including as a screening method for high-risk women, as a diagnostic tool used as an adjunct to mammography and ultrasound, and for the staging of disease extent prior to treatment. In addition to these uses, MRI is also employed to track small changes in tumor size and microenvironment. MRI has produced several early indicators of treatment response in clinical trials over the last 10 years, including initial lesion pattern, changes in lesion size, kinetic parameters, apparent diffusion coefficient and T2 value; the related technique of 1H MRS has also shown that choline concentration, T2 value and water-to-fat ratio are response indicators. In addition to measuring anatomical changes in the lesion size, as performed in traditional radiology, MRI has the ability to track vascular and cellular changes using dynamic contrast-enhanced MRI and diffusion-weighted MRI, respectively. By adding 1H MRS to MRI examinations, metabolic changes can also be determined. These functional imaging techniques allow studies to focus on early time points relative to neoadjuvant treatment. Early treatment response predictors may allow therapy to be tailored to individual patients and thus aid in the realization of the goal of personalized medicine. PMID:21692116

  11. Clinical Utility of Multimodality Imaging with Dynamic Contrast-Enhanced MRI, Diffusion-Weighted MRI, and 18F-FDG PET/CT for the Prediction of Neck Control in Oropharyngeal or Hypopharyngeal Squamous Cell Carcinoma Treated with Chemoradiation

    PubMed Central

    Chan, Sheng-Chieh; Lin, Yu-Chun; Yen, Tzu-Chen; Liao, Chun-Ta; Chang, Joseph Tung-Chieh; Ko, Sheung-Fat; Wang, Hung- Ming; Chang, Chee-Jen; Wang, Jiun-Jie

    2014-01-01

    The clinical usefulness of pretreatment imaging techniques for predicting neck control in patients with oropharyngeal or hypopharyngeal squamous cell carcinoma (OHSCC) treated with chemoradiation remains unclear. In this prospective study, we investigated the role of pretreatment dynamic contrast-enhanced perfusion MR imaging (DCE-PWI), diffusion-weighted MR imaging (DWI), and [18F]fluorodeoxyglucose-positron emission tomography (18F-FDG PET)/CT derived imaging markers for the prediction of neck control in OHSCC patients treated with chemoradiation. Patients with untreated OHSCC scheduled for chemoradiation between August, 2010 and July, 2012 were eligible for the study. Clinical variables and the following imaging parameters of metastatic neck lymph nodes were examined in relation to neck control: transfer constant, volume of blood plasma, and volume of extracellular extravascular space (Ve) on DCE-PWI; apparent diffusion coefficient (ADC) on DWI; maximum standardized uptake value, metabolic tumor volume, and total lesion glycolysis on 18F-FDG PET/CT. There were 69 patients (37 with oropharynx SCC and 32 with hypopharynx SCC) with successful pretreatment DCE-PWI and DWI available for analysis. After a median follow-up of 31 months, 25 (36.2%) participants had neck failure. Multivariate analysis identified hemoglobin level <14.3 g/dL (P?=?0.019), Ve <0.23 (P?=?0.040), and ADC >1.1410?3 mm2/s (P?=?0.003) as independent prognostic factors for 3-year neck control. A prognostic scoring system was formulated by summing up the three significant predictors of neck control. Patients with scores of 23 had significantly poorer neck control and overall survival rates than patients with scores of 01. We conclude that hemoglobin levels, Ve, and ADC are independent pretreatment prognostic factors for neck control in OHSCC treated with chemoradiation. Their combination may identify a subgroup of patients at high risk of developing neck failure. PMID:25531391

  12. Predictive Value of Imaging Markers at Multiple Sclerosis Disease Onset Based on Gadolinium- and USPIO-Enhanced MRI and Machine Learning

    PubMed Central

    Crimi, Alessandro; Commowick, Olivier; Maarouf, Adil; Ferré, Jean-Christophe; Bannier, Elise; Tourbah, Ayman; Berry, Isabelle; Ranjeva, Jean-Philippe; Edan, Gilles; Barillot, Christian

    2014-01-01

    Objectives A novel characterization of Clinically Isolated Syndrome (CIS) patients according to lesion patterns is proposed. More specifically, patients are classified according to the nature of inflammatory lesions patterns. It is expected that this characterization can infer new prospective figures from the earliest imaging signs of Multiple Sclerosis (MS), since it can provide a classification of different types of lesions across patients. Methods The method is based on a two-tiered classification. Initially, the spatio-temporal lesion patterns are classified. The discovered lesion patterns are then used to characterize groups of patients. The patient groups are validated using statistical measures and by correlations at 24-month follow-up with hypointense lesion loads. Results The methodology identified 3 statistically significantly different clusters of lesion patterns showing p-values smaller than 0.01. Moreover, these patterns defined at baseline correlated with chronic hypointense lesion volumes by follow-up with an score of . Conclusions The proposed methodology is capable of identifying three major different lesion patterns that are heterogeneously present in patients, allowing a patient classification using only two MRI scans. This finding may lead to more accurate prognosis and thus to more suitable treatments at early stage of MS. PMID:24691080

  13. Development of MRI Microscope

    NASA Astrophysics Data System (ADS)

    Hachiya, Mahiro; Arimura, Kyohei; Ueno, Tomohiro; Matsubara, Akira

    2010-02-01

    We have been developing an ultra high spatial resolution MRI, “MRI Microscope”, especially for 3He physics at ultra low temperature. The ultimate goal of our MRI Microscope is to achieve 1 μm×1 μm two dimensional spatial resolution comparable to optical microscopes. We constructed the MRI Microscope using a magnetic field of 7.2 T, with tri-axial magnetic field gradients of 2.0 T/m. We visualized the pure liquid 3He in a 230 μm diameter tube to study the effect of nonlinearity on the MRI Microscope at low temperature and in high magnetic fields. An MRI image was obtained at 0.22 MPa, 1 K with 1.8 μm×1.8 μm pixel size. At 65 mK, the MRI image became more blurred. We speculate that it was caused by large spin diffusion and nonlinearity.

  14. Activity-induced manganese-dependent MRI (AIM-MRI) and functional MRI in awake rabbits during somatosensory stimulation.

    PubMed

    Schroeder, Matthew P; Weiss, Craig; Procissi, Daniel; Wang, Lei; Disterhoft, John F

    2016-02-01

    Activity-induced manganese-dependent MRI (AIM-MRI) is a powerful tool to track system-wide neural activity using high resolution, quantitative T1-weighted MRI in animal models and has significant advantages for investigating neural activity over other modalities including BOLD fMRI. With AIM-MRI, Mn(2+) ions enter neurons via voltage-gated calcium channels preferentially active during the time of experimental exposure. A broad range of AIM-MRI studies using different species studying different phenomena have been performed, but few of these studies provide a systematic evaluation of the factors influencing the detection of Mn(2+) such as dosage and the temporal characteristics of Mn(2+) uptake. We identified an optimal dose of Mn(2+) (25mg/kg, s.c.) in order to characterize the time-course of Mn(2+) accumulation in active neural regions in the rabbit. T1-weighted MRI and functional MRI were collected 0-3, 6-9, and 24-27h post-Mn(2+) injection while the vibrissae on the right side were vibrated. Significant BOLD activation in the left somatosensory (SS) cortex and left ventral posteromedial (VPM) thalamic nucleus was detected during whisker vibration. T1-weighted signal intensities were extracted from these regions, their corresponding contralateral regions and the visual cortex (to serve as controls). A significant elevation in T1-weighted signal intensity in the left SS cortex (relative to right) was evident 6-9 and 24-27h post-Mn(2+) injection while the left VPM thalamus showed a significant enhancement (relative to the right) only during the 24-27h session. Visual cortex showed no hemispheric difference at any timepoint. Our results suggest that studies employing AIM-MRI would benefit by conducting experimental manipulations 6-24h after subcutaneous MnCl2 injections to optimize the concentration of contrast agent in the regions active during the exposure. PMID:26589332

  15. MRI-Guided Vascular Access with an Active Visualization Needle

    PubMed Central

    Saikus, Christina E.; Ratnayaka, Kanishka; Barbash, Israel M.; Colyer, Jessica H.; Kocaturk, Ozgur; Faranesh, Anthony Z.; Lederman, Robert J.

    2011-01-01

    Purpose To develop an approach to vascular access under MRI, as a component of comprehensive MRI-guided cardiovascular catheterization and intervention. Materials and Methods We attempted jugular vein access in healthy pigs as a model of difficult vascular access. Procedures were performed under real-time MRI guidance using reduced field of view imaging. We developed an active MRI antenna-needle having an open-lumen, distinct tip appearance and indicators of depth and trajectory, in order to enhance MRI visibility during the procedure. We compared performance of the active needle against an unmodified commercial passively-visualized needle, measured by procedure success among operators with different levels of experience. Results MRI-guided central vein access was feasible using both the active needle and the unmodified passive needle. The active needle required less time (88 vs. 244 sec, p=0.022) and fewer needle passes (4.5 vs. 9.1, p=0.028), irrespective of operator experience. Conclusion MRI-guided access to central veins is feasible in our animal model. When image guidance is necessary for vascular access, performing this component under MRI will allow wholly MRI-guided catheterization procedures that do not require adjunctive imaging facilities such as X-ray or ultrasound. The active needle design showed enhanced visibility, as expected. These capabilities may permit more complex catheter-based cardiovascular interventional procedures enabled by enhanced image guidance. PMID:22006552

  16. MRI Scans - Multiple Languages: MedlinePlus

    MedlinePLUS

    ... Arabic (???????) MRI (Magnetic Resonance Imaging) (Arabic) ??????? Bilingual PDF Health Information Translations Chinese - Simplified (????) MRI (Magnetic Resonance Imaging) ??????(MRI) - ???? (Chinese - Simplified) Bilingual PDF Health Information Translations Chinese - Traditional (????) MRI ( ...

  17. A single dose of the serotonin neurotransmission agonist paroxetine enhances motor output: double-blind, placebo-controlled, fMRI study in healthy subjects.

    PubMed

    Loubinoux, Isabelle; Pariente, Jrmie; Boulanouar, Kader; Carel, Christophe; Manelfe, Claude; Rascol, Olivier; Celsis, Pierre; Chollet, Franois

    2002-01-01

    Since serotonin (5-HT) stimulates motor function, pharmacological potentiation of 5-HT neurotransmission may improve motor function in healthy subjects and, possibly, recovery in post-stroke patients. Indeed, fluoxetine, a selective serotonin reuptake inhibitor (SSRI), increased activation in executive motor areas of healthy subjects as fenozolone, a releaser of monoamines (including noradrenaline, dopamine, and serotonin) from intracellular stores. This study is intended to test the hypothesis that paroxetine can likewise modulate brain motor activity in a dose-dependent manner in healthy subjects. In a double-blind counterbalanced study, six subjects underwent functional MRI examinations on three sessions 1 week apart (E1, E2, and E3) at the time of peak plasma concentrations (5 h after drug intake, i.e., either 20 or 60 mg of paroxetine or placebo) with a complex sequential opposition task. Rest and activation alternated in a block design. During activation, subjects performed, with the right hand, a 1-Hz-paced task that alternated two fist closings with a sequential opposition task. Paroxetine elicited effects similar to those reported for fluoxetine; notable changes were hyperactivation in the contralateral S1/M1, and posterior SMA and widespread hypoactivation of basal ganglia and cerebellum. There was an inverse correlation between dose and effect: significantly greater effects were observed with the 20-mg dose compared with 60 mg. Paroxetine dose-dependently modulates activation of the entire motor pathway in a way that favors motor output. Thus, a single dose of the SSRI paroxetine reorganized motor processing. PMID:11771971

  18. Duality of quantum coherence and path distinguishability

    NASA Astrophysics Data System (ADS)

    Bera, Manabendra Nath; Qureshi, Tabish; Siddiqui, Mohd Asad; Pati, Arun Kumar

    2015-07-01

    We derive a generalized wave-particle duality relation for arbitrary multipath quantum interference phenomena. Beyond the conventional notion of the wave nature of a quantum system, i.e., the interference fringe visibility, we introduce a quantifier as the normalized quantum coherence, recently defined in the framework of quantum information theory. To witness the particle nature, we quantify the path distinguishability or the which-path information based on unambiguous quantum state discrimination. Then, the Bohr complementarity principle for multipath quantum interference can be stated as a duality relation between the quantum coherence and the path distinguishability. For two-path interference, the quantum coherence is identical to the interference fringe visibility, and the relation reduces to the well-known complementarity relation. The duality relation continues to hold in the case where mixedness is introduced due to possible decoherence effects.

  19. The ambiguity of "distinguishability" in statistical mechanics

    NASA Astrophysics Data System (ADS)

    Swendsen, Robert H.

    2015-06-01

    Differences of opinion concerning fundamental issues in statistical mechanics directly related to the thermodynamic entropy have persisted through more than a century of debate. One reason is the lack of consensus on the definitions of key terms, especially the terms "distinguishable," "indistinguishable," and "identical." Several definitions occur in the literature, but are not always made explicit. The multiplicity of definitions has created confusion about the basic conditions under which entropy is to be defined. In this paper, I present an overview of definitions in current use for terms associated with distinguishability and relate them to various definitions that have been suggested for entropy. My hope is that consensus will be achievable if the definitions are clarified and agreed upon.

  20. Distinguishing Provenance Equivalence of Earth Science Data

    NASA Technical Reports Server (NTRS)

    Tilmes, Curt; Yesha, Ye; Halem, M.

    2010-01-01

    Reproducibility of scientific research relies on accurate and precise citation of data and the provenance of that data. Earth science data are often the result of applying complex data transformation and analysis workflows to vast quantities of data. Provenance information of data processing is used for a variety of purposes, including understanding the process and auditing as well as reproducibility. Certain provenance information is essential for producing scientifically equivalent data. Capturing and representing that provenance information and assigning identifiers suitable for precisely distinguishing data granules and datasets is needed for accurate comparisons. This paper discusses scientific equivalence and essential provenance for scientific reproducibility. We use the example of an operational earth science data processing system to illustrate the application of the technique of cascading digital signatures or hash chains to precisely identify sets of granules and as provenance equivalence identifiers to distinguish data made in an an equivalent manner.

  1. T1-Weighted Dynamic Contrast-Enhanced MRI as a Noninvasive Biomarker of Epidermal Growth Factor Receptor vIII Status

    PubMed Central

    Arevalo-Perez, J.; Thomas, A.A.; Kaley, T.; Lyo, J.; Peck, K.K.; Holodny, A.I.; Mellinghoff, I.K.; Shi, W.; Zhang, Z.; Young, R.J.

    2016-01-01

    BACKGROUND AND PURPOSE Epidermal growth factor receptor variant III is a common mutation in glioblastoma, found in approximately 25% of tumors. Epidermal growth factor receptor variant III may accelerate angiogenesis in malignant gliomas. We correlated T1-weighted dynamic contrast-enhanced MR imaging perfusion parameters with epidermal growth factor receptor variant III status. MATERIALS AND METHODS Eighty-two consecutive patients with glioblastoma and known epidermal growth factor receptor variant III status who had dynamic contrast-enhanced MR imaging before surgery were evaluated. Volumes of interest were drawn around the entire enhancing tumor on contrast T1-weighted images and then were transferred onto coregistered dynamic contrast-enhanced MR imaging perfusion maps. Histogram analysis with normalization was performed to determine the relative mean, 75th percentile, and 90th percentile values for plasma volume and contrast transfer coefficient. A Wilcoxon rank sum test was applied to assess the relationship between baseline perfusion parameters and positive epidermal growth factor receptor variant III status. The receiver operating characteristic method was used to select the cutoffs of the dynamic contrast-enhanced MR imaging perfusion parameters. RESULTS Increased relative plasma volume and increased relative contrast transfer coefficient parameters were both significantly associated with positive epidermal growth factor receptor variant III status. For epidermal growth factor receptor variant III–positive tumors, relative plasma volume mean was 9.3 and relative contrast transfer coefficient mean was 6.5; for epidermal growth factor receptor variant III–negative tumors, relative plasma volume mean was 3.6 and relative contrast transfer coefficient mean was 3.7 (relative plasma volume mean, P < .001, and relative contrast transfer coefficient mean, P = .008). The predictive powers of relative plasma volume histogram metrics outperformed those of the relative contrast transfer coefficient histogram metrics (P < = .004). CONCLUSIONS Dynamic contrast-enhanced MR imaging shows greater perfusion and leakiness in epidermal growth factor receptor variant III–positive glioblastomas than in epidermal growth factor receptor variant III–negative glioblastomas, consistent with the known effect of epidermal growth factor receptor variant III on angiogenesis. Quantitative evaluation of dynamic contrast-enhanced MR imaging may be useful as a noninvasive tool for correlating epidermal growth factor receptor variant III expression and related tumor neoangiogenesis. This potential may have implications for monitoring response to epidermal growth factor receptor variant III–targeted therapies. PMID:26338913

  2. Familial Identification: Population Structure and Relationship Distinguishability

    PubMed Central

    Rohlfs, Rori V.; Fullerton, Stephanie Malia; Weir, Bruce S.

    2012-01-01

    With the expansion of offender/arrestee DNA profile databases, genetic forensic identification has become commonplace in the United States criminal justice system. Implementation of familial searching has been proposed to extend forensic identification to family members of individuals with profiles in offender/arrestee DNA databases. In familial searching, a partial genetic profile match between a database entrant and a crime scene sample is used to implicate genetic relatives of the database entrant as potential sources of the crime scene sample. In addition to concerns regarding civil liberties, familial searching poses unanswered statistical questions. In this study, we define confidence intervals on estimated likelihood ratios for familial identification. Using these confidence intervals, we consider familial searching in a structured population. We show that relatives and unrelated individuals from population samples with lower gene diversity over the loci considered are less distinguishable. We also consider cases where the most appropriate population sample for individuals considered is unknown. We find that as a less appropriate population sample, and thus allele frequency distribution, is assumed, relatives and unrelated individuals become more difficult to distinguish. In addition, we show that relationship distinguishability increases with the number of markers considered, but decreases for more distant genetic familial relationships. All of these results indicate that caution is warranted in the application of familial searching in structured populations, such as in the United States. PMID:22346758

  3. Mobile instrumentation platform to distinguish airway disorders

    PubMed Central

    Schivo, Michael; Seichter, Felicia; Aksenov, Alexander A.; Pasamontes, Alberto; Peirano, Daniel J.; Mizaikoff, Boris; Kenyon, Nicholas J.; Davis, Cristina E.

    2013-01-01

    Asthma and chronic obstructive pulmonary disease (COPD) are distinct but clinically overlapping airway disorders which often create diagnostic and therapeutic dilemmas. Current strategies to discriminate these diseases are limited by insensitivity and poor performance due to biologic variability. We tested the hypothesis that a gas chromatograph / differential mobility spectrometer (GC/DMS) sensor could distinguish between clinically well-defined groups with airway disorders based on the volatile organic compounds (VOCs) obtained from exhaled breath. After comparing VOC profiles obtained from 13 asthma, 5 COPD, and 13 healthy control subjects, we found that VOC profiles distinguished asthma from healthy controls and also a subgroup of asthmatics taking the drug omalizumab from healthy controls. The VOC profiles could not distinguish between COPD and any of the other groups. Our results show a potential application of the GC/DMS for non-invasive and bedside diagnostics of asthma and asthma therapy monitoring. Future studies will focus on larger sample sizes and patient cohorts. PMID:23446184

  4. MRI Features of Hepatocellular Carcinoma Related to Biologic Behavior

    PubMed Central

    Cho, Eun-Suk

    2015-01-01

    Imaging studies including magnetic resonance imaging (MRI) play a crucial role in the diagnosis and staging of hepatocellular carcinoma (HCC). Several recent studies reveal a large number of MRI features related to the prognosis of HCC. In this review, we discuss various MRI features of HCC and their implications for the diagnosis and prognosis as imaging biomarkers. As a whole, the favorable MRI findings of HCC are small size, encapsulation, intralesional fat, high apparent diffusion coefficient (ADC) value, and smooth margins or hyperintensity on the hepatobiliary phase of gadoxetic acid-enhanced MRI. Unfavorable findings include large size, multifocality, low ADC value, non-smooth margins or hypointensity on hepatobiliary phase images. MRI findings are potential imaging biomarkers in patients with HCC. PMID:25995679

  5. MRI as a tool for the study of waterflooding processes in heterogeneous cores.

    PubMed

    Maddinelli, G; Brancolini, A

    1996-01-01

    NMR imaging has shown itself to be an important tool for improving analysis of flow behaviour during waterflooding in heterogeneous cores. Waterflooding is a widely employed technique in enhancing oil and gas recovery. However the success of such a process could be considerably reduced by instability of the displacing front with negative effects on production efficiency. MRI can be easily applied in evaluating the flow advancement because of its ability to distinguish different phases during dynamic experiments. In our study we have evaluated the shape of the displacing front during water injection in highly heterogeneous reservoir carbonates. The effect of petrographical heterogeneities which strongly characterize the rocks, revealed a marked influence on flow behaviour. Viscosity increase by polymer addition, in spite of a more favourable mobility ratio, resulted in a poorer performance because of higher channelling effects. The results of selected simulation experiments are discussed. PMID:8970109

  6. 10 CFR 1002.21 - Description of distinguishing flag.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Description of distinguishing flag. 1002.21 Section 1002.21 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) OFFICIAL SEAL AND DISTINGUISHING FLAG Distinguishing Flag § 1002.21 Description of distinguishing flag. (a) The base or field of the flag shall...

  7. PET versus SPECT in distinguishing radiation necrosis from tumor recurrence in the brain

    SciTech Connect

    Buchpiguel, C.A.; Alavi, J.B.; Alavi, A.

    1995-01-01

    Two cases of postsurgical brain tumor evaluation in which MRI was inconclusive are discussed. Functional imaging techniques, such as FDG-PET and {sup 201}TI SPECT, were used in both cases for distinguishing radiation necrosis from tumor recurrence. These methods proved to be complimentary. For Patient 1, FDG-PET showed more limitations compared to {sup 201}Tl SPECT. FDG-PET results, on the other hand, were consistent with the final diagnosis and the SPECT image was false positive for tumor recurrence in Patient 2. 26 refs., 9 figs.

  8. Quantum correlations and distinguishability of quantum states

    NASA Astrophysics Data System (ADS)

    Spehner, Dominique

    2014-07-01

    A survey of various concepts in quantum information is given, with a main emphasis on the distinguishability of quantum states and quantum correlations. Covered topics include generalized and least square measurements, state discrimination, quantum relative entropies, the Bures distance on the set of quantum states, the quantum Fisher information, the quantum Chernoff bound, bipartite entanglement, the quantum discord, and geometrical measures of quantum correlations. The article is intended both for physicists interested not only by collections of results but also by the mathematical methods justifying them, and for mathematicians looking for an up-to-date introductory course on these subjects, which are mainly developed in the physics literature.

  9. Can cosmic parallax distinguish between anisotropic cosmologies?

    SciTech Connect

    Fontanini, Michele; West, Eric J.; Trodden, Mark

    2009-12-15

    In an anisotropic universe, observers not positioned at a point of special symmetry should observe cosmic parallax--the relative angular motion of test galaxies over cosmic time. It was recently argued that the nonobservance of this effect in upcoming precision astrometry missions such as GAIA may be used to place strong bounds on the position of off-center observers in a void-model universe described by the Lemaitre-Tolman-Bondi metric. We consider the analogous effect in anisotropic cosmological models described by an axisymmetric homogeneous Bianchi type I metric and discuss whether any observation of cosmic parallax would distinguish between different anisotropic evolutions.

  10. Quantum correlations and distinguishability of quantum states

    SciTech Connect

    Spehner, Dominique

    2014-07-15

    A survey of various concepts in quantum information is given, with a main emphasis on the distinguishability of quantum states and quantum correlations. Covered topics include generalized and least square measurements, state discrimination, quantum relative entropies, the Bures distance on the set of quantum states, the quantum Fisher information, the quantum Chernoff bound, bipartite entanglement, the quantum discord, and geometrical measures of quantum correlations. The article is intended both for physicists interested not only by collections of results but also by the mathematical methods justifying them, and for mathematicians looking for an up-to-date introductory course on these subjects, which are mainly developed in the physics literature.

  11. Characteristics that distinguish types of epithermal deposits

    USGS Publications Warehouse

    Hayba, D.O.; Foley, N.K.; Heald-Wetlaufer, P.

    1984-01-01

    Three distinctive groupings of epithermal deposits were recognized from a literature study of fifteen well-described precious- and base-metal epithermal districts, supplemented by L. J. Buchanan's 1981 compilation of data from 47 less completely documented deposits. The three groups are distinguished primarily by the type of alteration and the sulfur fugacity indicated by the vein mineral assemblage. Additional discriminating criteria include composition of the host rock, timing of ore deposition relative to emplacement of the host, and relative abundances of gold, silver, and base metals.

  12. Detectability of MRI Turbulence in Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Teague, Richard; Semenov, Dmitry; Flock, Mario; Henning, Thomas

    2015-08-01

    Protoplanetary disks are the nurseries of planet formation. Within them, turbulence acts as a stirring mechanism, combining the large population of small grains successively into pebbles, planetesimals and eventually planetary cores. There are many tuburbulent mechanisms proposed to fulfil this role, however, current observations are not sufficient to distinguish one mechanism from the other.This poster looks at the hallmarks of magneto-rotational instabilities (MRI), which relies on the coupling of the gas to the magnetic fields of the disk. Previous attempts to determine the electron fraction necessary for MRI to be present are hampered by the lack of atomic ions observed in disks and a large uncertainty when scaling abundance molecualr ions which are readily observed.It has been shown with global-MHD models, however, that MRI turbulence can incite distinct azimuthal dependent strucutres in the gas of the disk. We explore the possibility of identifying this non-Keplerian nature of a disk's kinematical structure and discuss whether, through a mode analysis of the kinematic structure, one can isolate MRI tuburlence from other forms with full ALMA capabilities.

  13. Hybrid-SPRITE MRI

    NASA Astrophysics Data System (ADS)

    Xiao, Dan; Balcom, Bruce J.

    2013-10-01

    In a FID based frequency encoding MRI experiment the central part of k-space is not generally accessible due to the probe dead time. This portion of k-space is however crucial for image reconstruction. SPRITE (Single Point Ramped Imaging with T1 Enhancement), SPI with a linearly ramped phase encode gradient, has been employed to image short relaxation time systems for many years with great success. It is a robust imaging method in significant measure because it provides acquisition of high quality k-space origin data. We propose a new sampling scheme, termed hybrid-SPRITE, combining phase and frequency encoding to ensure high quality images with reduced acquisition times, reduced gradient duty cycle and increased sensitivity. In hybrid-SPRITE, numerous time domain points are collected to assist image reconstruction. An Inverse Non-uniform Discrete Fourier Transform (INDFT) is employed in 1D applications. A pseudo-polar grid is exploited in 2D hybrid-SPRITE for rapid and accurate image reconstruction.

  14. Hybrid-SPRITE MRI.

    PubMed

    Xiao, Dan; Balcom, Bruce J

    2013-10-01

    In a FID based frequency encoding MRI experiment the central part of k-space is not generally accessible due to the probe dead time. This portion of k-space is however crucial for image reconstruction. SPRITE (Single Point Ramped Imaging with T1 Enhancement), SPI with a linearly ramped phase encode gradient, has been employed to image short relaxation time systems for many years with great success. It is a robust imaging method in significant measure because it provides acquisition of high quality k-space origin data. We propose a new sampling scheme, termed hybrid-SPRITE, combining phase and frequency encoding to ensure high quality images with reduced acquisition times, reduced gradient duty cycle and increased sensitivity. In hybrid-SPRITE, numerous time domain points are collected to assist image reconstruction. An Inverse Non-uniform Discrete Fourier Transform (INDFT) is employed in 1D applications. A pseudo-polar grid is exploited in 2D hybrid-SPRITE for rapid and accurate image reconstruction. PMID:23916990

  15. Pharmacological enhancement of disc diffusion and differentiation of healthy, ageing and degenerated discs : Results from in-vivo serial post-contrast MRI studies in 365 human lumbar discs.

    PubMed

    Rajasekaran, S; Venkatadass, K; Naresh Babu, J; Ganesh, K; Shetty, Ajoy P

    2008-05-01

    Degenerative disc disease (DDD) is still a poorly understood phenomenon because of the lack of availability of precise definition of healthy, ageing and degenerated discs. Decreased nutrition is the final common pathway for DDD and the status of the endplate (EP) plays a crucial role in controlling the extent of diffusion, which is the only source of nutrition. The vascular channels in the subchondral plate have muscarinic receptors but the possibility of enhancing diffusion pharmacologically by dilation of these vessels has not been probed. Although it is well accepted that EP damage will affect diffusion and thereby nutrition, there is no described method to quantify the extent of EP damage. Precise definitions with an objective method of differentiating healthy, ageing and degenerated discs on the basis of anatomical integrity of the disc and physiological basis of altered nutrition will be useful. This information is an urgent necessity for better understanding of DDD and also strategizing prevention and treatment. Seven hundred and thirty endplates of 365 lumbar discs from 73 individuals (26 healthy volunteers and 47 patients) with age ranging from 10-64 years were evaluated by pre-contrast and 10 min, 2, 4, 6 and 12 h post contrast MRI after IV injection of 0.3 mmol/kg of Gadodiamide. End plates were classified according to the extent of damage into six grades and an incremental score was given for each category. A total endplate score (TEPS) was derived by adding the EP score of the two endplates for each concerned disc. The base line value (SI(base)) and the signal intensity at particular time periods were used to derive the enhancement percentage for each time period (Enhancement (%) = SI(tp) - SI(base)/SI(base) x 100). The enhancement percentage for each time period, the time for peak enhancement (T-max) and the time intensity curve (TIC) over 12 h were used to study and compare the diffusion characteristics. The differences in pattern of diffusion were obvious visually at 4 h which was categorized into five patterns-Pattern A representing normal diffusion to Pattern E representing a total abnormality in diffusion. Degeneration was classified according to Pfirrmann's grading and this was correlated to the TEPS and the alterations in diffusion patterns. The relationship of TEPS on the increase in DDD was evaluated by a logistic curve and the cut point for severe DDD was found by ROC curve. The influence of the variables of age, level, Modic changes, instability, annulus fibrosis defect (DEBIT), TEPS and diffusion patterns on DDD was analyzed by multiple and stepwise regression analysis. Oral nimodipine study: Additional forty lumbar end-plates from four young healthy volunteers were studied to document the effect of oral nimodipine. Pre-drug diffusion levels were studied by pre and post contrast MRI (0.3 mmol/kg of gadodiamide) at 10 min, 2, 4, 6, 12 and 24 h. Oral nimodipine was administered (30 mg QID) for 5 days and post-contrast MRI studies were performed similarly. Enhancement was calculated at vertebral body-VB; subchondral bone-SCB; Endplate Zone-EPZ and at superior and inferior peripheral nucleus pulposus-PNP and central nucleus pulposus-CNP, using appropriate cursors by a blinded investigator. Paired sample t test and area under curve (AUC) measurements were done.The incidence of disc degeneration had a significant correlation with increasing TEPS (Trend Chi-square, P < 0.01). Only one out of 83 (1.2%) disc had either Pfirrmann Grade IV or V when the score was 4 or below when compared to 34/190 (17.9%) for scores 5-7; 41 of 72 (56.9%) for scores 8-10 and 18 of 20 (90%) for scores 11 and 12 (P < 0.001 for all groups). Pearson's correlation between TEPS and DDD was statistically significant, irrespective of the level of disc or different age groups (r value was above 0.6 and P < 0.01 for all age groups). Logistic curve fit analysis and ROC curve analysis showed that the incidence of DDD increased abruptly when the TEPS crossed six. With a progressive increase of end plate damage, five different p

  16. Direct MRI detection of impending plaque development in multiple sclerosis

    PubMed Central

    Absinta, Martina; Nair, Govind; Sati, Pascal; Cortese, Irene C.M.; Filippi, Massimo

    2015-01-01

    Objectives: To detect and localize MRI signal changes prior to the parenchymal contrast enhancement that classically defines the radiologic onset of the developing white matter lesion in multiple sclerosis (MS). Methods: We reviewed 308 high-resolution (≤1 mm3 voxels) MRI scans at 3T and 7T in 29 patients with active MS. The presence of pre-parenchymal enhancement abnormalities before the appearance of parenchymal enhancement was evaluated in all available scans. Results: Pre-enhancement signal changes were noted in 26 of 162 enhancing lesions (16%) as linear enhancement of the central vein and/or perivenular hyperintense signal on T2 fluid-attenuated inversion recovery or T2* images. They occur up to 2 months before focal enhancement within the parenchyma in 10% of cases. Conclusions: In some lesions, the abrupt opening of the blood-brain barrier, detected by contrast enhancement on MRI, can have directly visible antecedent MRI changes centered on the central vein. We propose that these findings might be the basis for prior reports of subtle pre-parenchymal enhancement changes in quantitative MRI indices. In line with the venulocentric model of lesion development, our findings are consistent with the centrality of early perivenular events in lesion formation in vivo. PMID:26401516

  17. Getting an MRI

    MedlinePLUS Videos and Cool Tools

    ... Q&A Movies & More Quizzes Kids' Dictionary of Medical Words En Español What Other Kids Are Reading Movie: Digestive System Winter Sports: Sledding, Skiing, Snowboarding, Skating Crushes What's a Booger? Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) Print ...

  18. In Situ Non-Invasive T2*-Weighted MRI Derived Parameters Determine Ex Vivo Structural Properties of an ACL Reconstruction or Bio-enhanced Primary Repair in a Porcine Model

    PubMed Central

    Biercevicz, Alison M.; Miranda, Danny L.; Machan, Jason T.; Murray, Martha M.; Fleming, Braden C.

    2012-01-01

    Background Magnetic resonance imaging (MRI) is a noninvasive technology that can quantitatively access ACL graft size and signal intensity. However, how those properties relate to reconstructed or repaired ligament strength during the healing process is yet unknown. Purpose We hypothesized that MR derived measures of graft volume and signal intensity are significant predictors of the structural properties of a healing ACL or ACL graft after 15 weeks and 52 weeks of healing. Study Design Controlled Laboratory Experiment Methods The current data were gathered from two experiments evaluating ACL reconstruction and repair techniques. In the first experiment, pigs underwent unilateral ACL transection and received: 1) ACL reconstruction, 2) ACL reconstruction with collagen platelet composite (CPC), or 3) no treatment. The surgical legs were harvested following 15 weeks of healing. In the second experiment, pigs underwent ACL transection and received: 1) ACL reconstruction, 2) ACL reconstruction with CPC, 3) bio-enhanced ACL primary repair with CPC, or 4) no treatment. The surgical legs were harvested after 52 weeks. The harvested knees were imaged using a T2* weighted 3D-CISS sequence. Each ligament was segmented from the scans, and the intra-articular volume and the median grayscale values were determined. Mechanical testing was performed to establish the ligament structural properties. Results Volume significantly predicted the structural properties (maximum load, yield load, linear stiffness) of the ligaments and grafts (R2 = 0.56, 0.56, 0.49; p?0.001). Likewise, the median grayscale values significantly predicted the structural properties of the ligaments and grafts (R2 = 0.42, 0.37, 0.40; p<0.001). The combination of these two parameters in a multiple regression model improved the predictions (R2 = 0.73, 0.72, 0.68; p?0.001). Conclusion Volume and grayscale values from high resolution T2* weighted MRI images are predictive of structural properties of the healing ligament or graft in a porcine model. Clinical Relevance This study provides a critical step in the development of a non-invasive method to predict the structural properties of the healing ACL graft or repair. This technique may prove beneficial as a surrogate outcome measure in pre-clinical animal and clinical studies. PMID:23348076

  19. Comparison of PET-FDG and SPECT TL-201 in distinguishing radiation necrosis from tumor recurrence in the brain

    SciTech Connect

    Buchpiguel, C.A.; Alavi, J.B.; Alavi, A.

    1994-05-01

    CT and MRI scans are quite sensitive in detecting brain tumors. However, with both imaging techniques limitations have been reported in distinguishing tumor recurrence from radiation necrosis. Metabolic imaging methods such as PET-FDG and SPECT T1-201 have been utilized for differentiating radiation necrosis from tumor recurrence. However, no study was to compare PET-FDG and SPECT T1-201 in primary brain tumors.

  20. Spatial memory training induces morphological changes detected by manganese-enhanced MRI in the hippocampal CA3 mossy fiber terminal zone.

    PubMed

    Zhang, Binbin; Chuang, Kai-Hsiang; Tjio, Ci'en; Chen, Way Cherng; Sheu, Fwu-Shan; Routtenberg, Aryeh

    2016-03-01

    Hippocampal mossy fibers (MFs) can show plasticity of their axon terminal arbor consequent to learning a spatial memory task. Such plasticity is seen as translaminar sprouting from the stratum lucidum (SL) of CA3 into the stratum pyramidale (SP) and the stratum oriens (SO). However, the functional role of this presynaptic remodeling is still obscure. In vivo imaging that allows longitudinal observation of such remodeling could provide a deeper understanding of this presynaptic growth phenomenon as it occurs over time. Here we used manganese-enhanced magnetic resonance imaging (MEMRI), which shows a high-contrast area that co-localizes with the MFs. This technique was applied in the detection of learning-induced MF plasticity in two strains of rats. Quantitative analysis of a series of sections in the rostral dorsal hippocampus showed increases in the CA3a' area in MEMRI of trained Wistar rats consistent with the increased SO+SP area seen in the Timm's staining. MF plasticity was not seen in the trained Lister-Hooded rats in either MEMRI or in Timm's staining. This indicates the potential of MEMRI for revealing neuro-architectures and plasticity of the hippocampal MF system in vivo in longitudinal studies. PMID:26254115

  1. Preparation and in vitro evaluation of folate-receptor-targeted SPION-polymer micelle hybrids for MRI contrast enhancement in cancer imaging

    NASA Astrophysics Data System (ADS)

    Mahajan, Shveta; Koul, Veena; Choudhary, Veena; Shishodia, Gauri; Bharti, Alok C.

    2013-01-01

    Polymer-SPION hybrids were investigated for receptor-mediated localization in tumour tissue. Superparamagnetic iron oxide nanoparticles (SPIONs) prepared by high-temperature decomposition of iron acetylacetonate were monodisperse (9.27 3.37 nm), with high saturation magnetization of 76.8 emu g-1. Amphiphilic copolymers prepared from methyl methacrylate and PEG methacrylate by atom transfer radical polymerization were conjugated with folic acid (for folate-receptor specificity). The folate-conjugated polymer had a low critical micellar concentration (0.4 mg l-1), indicating stability of the micellar formulation. SPION-polymeric micelle clusters were prepared by desolvation of the SPION dispersion/polymer solution in water. Magnetic resonance imaging of the formulation revealed very good contrast enhancement, with transverse (T2) relaxivity of 260.4 mM-1 s-1. The biological evaluation of the SPION micelles included cellular viability assay (MTT) and uptake in HeLa cells. These studies demonstrated the potential use of these nanoplatforms for imaging and targeting.

  2. Distinguishing Asthma Phenotypes Using Machine Learning Approaches.

    PubMed

    Howard, Rebecca; Rattray, Magnus; Prosperi, Mattia; Custovic, Adnan

    2015-07-01

    Asthma is not a single disease, but an umbrella term for a number of distinct diseases, each of which are caused by a distinct underlying pathophysiological mechanism. These discrete disease entities are often labelled as 'asthma endotypes'. The discovery of different asthma subtypes has moved from subjective approaches in which putative phenotypes are assigned by experts to data-driven ones which incorporate machine learning. This review focuses on the methodological developments of one such machine learning technique-latent class analysis-and how it has contributed to distinguishing asthma and wheezing subtypes in childhood. It also gives a clinical perspective, presenting the findings of studies from the past 5 years that used this approach. The identification of true asthma endotypes may be a crucial step towards understanding their distinct pathophysiological mechanisms, which could ultimately lead to more precise prevention strategies, identification of novel therapeutic targets and the development of effective personalized therapies. PMID:26143394

  3. Novel approaches to imaging epilepsy by MRI

    PubMed Central

    Hetherington, Hoby

    2009-01-01

    As the concept of a network of injury has emerged in the treatment of epilepsy, the importance of evaluating that network noninvasively has also grown. Recently, studies utilizing magnetic resonance spectroscopic imaging, manganese-enhanced MRI and functional (f)MRI measures of resting state connectivity have demonstrated their ability to detect injury and dysfunction in cerebral networks involved in the propagation of seizures. The ability to noninvasively detect neuronal injury and dysfunction throughout cerebral networks should improve surgical planning, provide guidance for placement of devices that target network propagation and provide insights into the mechanisms of recurrence following resective surgery. PMID:20161076

  4. Hyperpolarized xenon in NMR and MRI.

    PubMed

    Oros, Ana-Maria; Shah, N Jon

    2004-10-21

    Hyperpolarized gases have found a steadily increasing range of applications in nuclear magnetic resonance (NMR) and NMR imaging (MRI). They can be regarded as a new class of MR contrast agent or as a way of greatly enhancing the temporal resolution of the measurement of processes relevant to areas as diverse as materials science and biomedicine. We concentrate on the properties and applications of hyperpolarized xenon. This review discusses the physics of producing hyperpolarization, the NMR-relevant properties of 129Xe, specific MRI methods for hyperpolarized gases, applications of xenon to biology and medicine, polarization transfer to other nuclear species and low-field imaging. PMID:15566166

  5. The initial Trinidad experience with Cine MRI in clinical cardiology.

    PubMed

    Thomas, C N; Maharaj, P; Bodapati, S; John, R; Rahaman, R; Henry, R; Brann, S

    2002-03-01

    We describe the initial Trinidad experience with Magnetic Resonance Imaging (MRI) and Cine MRI as a diagnostic tool in clinical cardiology. Six patients from the following categories were referred for Cine MRI evaluation: congenital heart disease, valvular heart disease, aortic diseases, cardiomyopathy and intracardiac mass. All patients underwent echocardiography. MRI and Cine MRI were performed on all patients using a Siemens Magnetom 1.0 Tesla MR system at MRI Trinidad and Tobago Ltd. Selected patients underwent Angiography and/or computed tomography (CT) scanning. Clinical data and images of the six patients evaluated are described. MRI and Cine MRI provided excellent anatomical and functional details of the heart and aorta in five patients with dissection of the aorta, aneurysm of the ascending aorta, suspected left ventricular apical thrombus, infiltrative cardiomyopathy and arrhythmogenic right ventricular dysplasia. Technical difficulty was experienced with one patient who had a congenital defect (common atrium). In this study, Cine MRI provided excellent images in all but one patient. This new noninvasive technique enhanced diagnostic capabilities and facilitated management in patients with certain cardiovascular diseases. PMID:12089881

  6. Functional MRI today.

    PubMed

    Bandettini, Peter

    2007-02-01

    Most brain imaging researchers would agree with the assertion that functional MRI (fMRI) is progressing. Since fMRI began in 1991, the number of people, papers, and abstracts related to fMRI has been increasing; the technology and methodology has shown advances in robustness and sophistication; the physiology of the signal is better understood; and, even though it hasn't yet made significant headway into the clinical setting, applications are widening. Questions that stem from this optimistic and perhaps overly general set of observations include those that ask what the ultimate theoretical and practical limits of fMRI are and how close are we to approaching these limits. In this commentary, I attempt to provide a snapshot of fMRI as it exists at the end of 2005, and to give a clear impression that not only are we progressing by "dotting the i's and crossing the t's" but that fundamental changes in fMRI methodology and processing are being put forth as the field matures. PMID:16842871

  7. Non-invasive breast biopsy method using GD-DTPA contrast enhanced MRI series and F-18-FDG PET/CT dynamic image series

    NASA Astrophysics Data System (ADS)

    Magri, Alphonso William

    This study was undertaken to develop a nonsurgical breast biopsy from Gd-DTPA Contrast Enhanced Magnetic Resonance (CE-MR) images and F-18-FDG PET/CT dynamic image series. A five-step process was developed to accomplish this. (1) Dynamic PET series were nonrigidly registered to the initial frame using a finite element method (FEM) based registration that requires fiducial skin markers to sample the displacement field between image frames. A commercial FEM package (ANSYS) was used for meshing and FEM calculations. Dynamic PET image series registrations were evaluated using similarity measurements SAVD and NCC. (2) Dynamic CE-MR series were nonrigidly registered to the initial frame using two registration methods: a multi-resolution free-form deformation (FFD) registration driven by normalized mutual information, and a FEM-based registration method. Dynamic CE-MR image series registrations were evaluated using similarity measurements, localization measurements, and qualitative comparison of motion artifacts. FFD registration was found to be superior to FEM-based registration. (3) Nonlinear curve fitting was performed for each voxel of the PET/CT volume of activity versus time, based on a realistic two-compartmental Patlak model. Three parameters for this model were fitted; two of them describe the activity levels in the blood and in the cellular compartment, while the third characterizes the washout rate of F-18-FDG from the cellular compartment. (4) Nonlinear curve fitting was performed for each voxel of the MR volume of signal intensity versus time, based on a realistic two-compartment Brix model. Three parameters for this model were fitted: rate of Gd exiting the compartment, representing the extracellular space of a lesion; rate of Gd exiting a blood compartment; and a parameter that characterizes the strength of signal intensities. Curve fitting used for PET/CT and MR series was accomplished by application of the Levenburg-Marquardt nonlinear regression algorithm. The best-fit parameters were used to create 3D parametric images. Compartmental modeling evaluation was based on the ability of parameter values to differentiate between tissue types. This evaluation was used on registered and unregistered image series and found that registration improved results. (5) PET and MR parametric images were registered through FEM- and FFD-based registration. Parametric image registration was evaluated using similarity measurements, target registration error, and qualitative comparison. Comparing FFD and FEM-based registration results showed that the FEM method is superior. This five-step process constitutes a novel multifaceted approach to a nonsurgical breast biopsy that successfully executes each step. Comparison of this method to biopsy still needs to be done with a larger set of subject data.

  8. Misleading FLAIR imaging pattern after glioma surgery with intraoperative MRI.

    PubMed

    Lescher, Stephanie; Jurcoane, Alina; Schniewindt, Sonja; Senft, Christian; Hattingen, Elke

    2016-01-01

    Intraoperative MRI (iMRI) allows a more detailed appreciation of the extent of resection than does conventional neurosurgery and results in longer overall survival in patients with malignant glioma. However, it is unknown whether the intraoperative application of contrast agent influences the early postsurgical MRI. The preceding iMRI could alter the signals of MR sequences in the early postsurgical MRI, especially in sequences influenced by T1 contrast. Hereby, we investigate such iMRI-induced influences on the fluid-attenuated inversion recovery (FLAIR) sequence. We retrospectively analyzed postsurgical T2w, T1w, and FLAIR images by visual inspection and by signal measurements in 46 patients with malignant gliomas after tumor resection. Of these, n?=?25 patients were operated with conventional microsurgery, and n?=?21 patients were operated with contrast-enhanced iMRI-guided microsurgery. We measured signal intensity in the resection cavity, in the cerebrospinal fluid (CSF) of the ventricles, and in the normal brain tissue contralateral to the tumor-bearing hemisphere on axial FLAIR images and T1-weighted and T2-weighted images. In 18 patients, the FLAIR sequence revealed hyperintense signal changes of the CSF in the subarachnoid or ventricular spaces. Seventeen of these 18 patients had received intraoperative MRI. In both FLAIR and T1-weighted images, the signal of the CSF in the ventricles was significantly higher in patients with iMRI than in patients without iMRI. The intraoperative application of contrast agent that is used for iMRI significantly influences postsurgical MRI within the first 72h. We found hyperintense signal changes of the CSF in the FLAIR sequence in the subarachnoid and intraventricular spaces mimicking subarachnoid hemorrhage. The findings may result in a misdiagnosis of subarachnoid hemorrhage (SAH) in these patients. PMID:26201972

  9. MRI in perianal fistulae

    PubMed Central

    Khera, Pushpinder S; Badawi, Hesham A; Afifi, Ahmed H

    2010-01-01

    MRI has become the method of choice for evaluating perianal fistulae due to its ability to display the anatomy of the sphincter muscles orthogonally, with good contrast resolution. In this article we give an outline of the classification of perianal fistulae and present a pictorial assay of sphincter anatomy and the MRI findings in perianal fistulae. This study is based on a retrospective analysis of 43 patients with a clinical diagnosis of perianal fistula. MRI revealed a total of 44 fistulae in 35 patients; eight patients had only perianal sinuses. PMID:20351996

  10. Clinical application of MRI in ophthalmology

    PubMed Central

    Townsend, Kelly A.; Wollstein, Gadi; Schuman, Joel S.

    2010-01-01

    MRI has long been applied to clinical medical and neurological cases for the structural assessment of tissues as well as their physiological and functional needs and processes. These uses are at a variety of developmental stages in ophthalmology, from common use of clinical structural assessment for neuro-ophthalmology and evaluation of space-occupying lesions to the beginning stages of experimentally measuring functional activation of specific layers within the retina and measurement of physiological oxygen responses. New MRI methodologies, such as the use of orbital coils and Gd-DTPA image enhancement, have been researched, developed, and validated in the eye, opening new possibilities for this technology to enter the clinic. This review aims to summarize the clinical ophthalmological uses of MRI, focusing on the current use of the technology and future applications. PMID:18384176

  11. Diagnostic value of MRI for odontogenic tumours

    PubMed Central

    Fujita, M; Matsuzaki, H; Yanagi, Y; Hara, M; Katase, N; Hisatomi, M; Unetsubo, T; Konouchi, H; Nagatsuka, H; Asaumi, J-I

    2013-01-01

    Objectives: To evaluate the diagnostic value of MRI for odontogenic tumours. Materials and methods: 51 patients with odontogenic tumours were subjected to pre-operative MRI examinations. For tumours with liquid components, i.e. ameloblastomas and keratocystic odontogenic tumours (KCOTs), the signal intensity (SI) uniformity of their cystic components (U?) was calculated and then their U? values were compared. For tumours with solid components that had been examined using dynamic contrast-enhanced MRI (DCE-MRI), their CImax (maximum contrast index), Tmax (the time when CImax occurred), CIpeak (CImax??0.90), Tpeak (the time when CIpeak occurred) and CI300 (i.e. the CI observed at 300?s after contrast medium injection) values were determined from CI curves. We then classified the odontogenic tumours according to their DCE-MRI parameters. Results: Significant differences between the U? values of the ameloblastomas and KCOT were observed on T1 weighted images, T2 weighted images and short TI inversion recovery images. Depending on their DCE-MRI parameters, we classified the odontogenic tumours into the following five types: Type A, CIpeak?>?2.0 and Tpeak??2.0 and Tmax??2.0 and Tmax?>?600?s; Type E, CI300??600?s. Conclusion: Cystic component SI uniformity was found to be useful for differentiating between ameloblastomas and KCOT. However, the DCE-MRI parameters of odontogenic tumours, except for odontogenic fibromas and odontogenic myxomas, contributed little to their differential diagnosis. PMID:23468124

  12. Implantable medical devices MRI safe.

    PubMed

    Dal Molin, Renzo; Hecker, Bertrand

    2013-01-01

    Pacemakers, ICDs, neurostimulators like deep brain stimulator electrodes, spiral cord stimulators, insulin pumps, cochlear implants, retinal implants, hearing aids, electro cardio gram (ECG) leads, or devices in interventional MRI such as vascular guide wires or catheters are affected by MRI magnetic and electromagnetic fields. Design of MRI Safe medical devices requires computer modeling, bench testing, phantom testing, and animal studies. Implanted medical devices can be MRI unsafe, MRI conditional or MRI safe (see glossary). In the following paragraphs we will investigate how to design implanted medical devices MRI safe. PMID:23739365

  13. Benchmarking the ERG valve tip and MRI Interventions Smart Flow neurocatheter convection-enhanced delivery system's performance in a gel model of the brain: employing infusion protocols proposed for gene therapy for Parkinson's disease

    NASA Astrophysics Data System (ADS)

    Sillay, Karl; Schomberg, Dominic; Hinchman, Angelica; Kumbier, Lauren; Ross, Chris; Kubota, Ken; Brodsky, Ethan; Miranpuri, Gurwattan

    2012-04-01

    Convection-enhanced delivery (CED) is an advanced infusion technique used to deliver therapeutic agents into the brain. CED has shown promise in recent clinical trials. Independent verification of published parameters is warranted with benchmark testing of published parameters in applicable models such as gel phantoms, ex vivo tissue and in vivo non-human animal models to effectively inform planned and future clinical therapies. In the current study, specific performance characteristics of two CED infusion catheter systems, such as backflow, infusion cloud morphology, volume of distribution (mm3) versus the infused volume (mm3) (Vd/Vi) ratios, rate of infusion (l min-1) and pressure (mmHg), were examined to ensure published performance standards for the ERG valve-tip (VT) catheter. We tested the hypothesis that the ERG VT catheter with an infusion protocol of a steady 1 l min-1 functionality is comparable to the newly FDA approved MRI Interventions Smart Flow (SF) catheter with the UCSF infusion protocol in an agarose gel model. In the gel phantom models, no significant difference was found in performance parameters between the VT and SF catheter. We report, for the first time, such benchmark characteristics in CED between these two otherwise similar single-end port VT with stylet and end-port non-stylet infusion systems. Results of the current study in agarose gel models suggest that the performance of the VT catheter is comparable to the SF catheter and warrants further investigation as a tool in the armamentarium of CED techniques for eventual clinical use and application.

  14. MRI 3D tissue temperature distribution measurement

    NASA Astrophysics Data System (ADS)

    Chen, Yichao; Gnyawali, Surya C.; Liu, Hong; Tesiram, Yasvir A.; Abbott, Andrew; Towner, Rheal A.; Chen, Wei R.

    2007-02-01

    A highly accurate, fast three-dimensional in vivo temperature mapping method is developed using MRI water photon chemical shift. It is important to have the precise temperature distribution information during laser-tissue thermal treatment. Several methods can be used for temperature measurement including thermal couple, optical fiber sensor, and MRI (magnetic resonance imaging) methods. MRI is the only feasible method for 3D in vivo, non-invasive temperature distribution measurement for laser-tissue interaction. The water proton chemical shift method is used in 3D MRI mapping. Varies MRI parameters, such as flip angle, TE, TR, spatial resolution, and temporal repetition, were optimized for the temperature mapping. The laser radiation of 805nm wavelength and a light-absorbing dye, indocyanine green (ICG) was used for temperature elevation. The measurement was conducted using gel phantom, chicken tissue and rats. The phantom system was constructed with a dye-enhanced spherical gel embedded in uniform gel phantom, simulating a tumor within normal tissue. The normal temperature elevation within ex vivo tissue such as chicken breast can reach up to 45-50 degree C with a power density of 1.3W/cm2 (with laser power of 3W and 1.7cm beam size). The temperature resolution is 0.37 degree C with a 0.2-mm spatial resolution and repetition rate of around 40 seconds. The external magnetic field drift effect is also evaluated.

  15. Award for Distinguished Scientific Early Career Contributions to Psychology: Robert E. Ployhart

    ERIC Educational Resources Information Center

    American Psychologist, 2009

    2009-01-01

    Robert E. Ployhart, recipient of the Award for Distinguished Scientific Early Career Contributions to Psychology, is cited for innovative work in examining reactions to staffing practices and efforts to enhance the acceptability of recruitment and staffing practices; for exemplary use of applied statistical models in examining multilevel effects…

  16. Ultraviolet plumage reflectance distinguishes sibling bird species.

    PubMed

    Bleiweiss, Robert

    2004-11-23

    Realistic studies of plumage color need to consider that many birds can see near-UV light, which normal humans cannot perceive. Although previous investigations have revealed that UV-based plumage reflectance is an important component of various intraspecific social signals, the contribution of UV signals to inter-specific divergence and speciation in birds remains largely unexplored. I describe an avian example of an interspecific phenomenon in which related sympatric species that appear similar to humans (sibling species) differ dramatically in the UV. Both UV video images and physical reflectance spectra indicate that the dorsal plumage of the tanager Anisognathus notabilis has a strong UV-limited reflectance band that readily distinguishes this species from its sibling congener Anisognathus flavinuchus. The main human-visible distinction between A. notabilis (olive back) and coexisting A. flavinuchus (black back) also occurs among different geographic populations of A. flavinuchus. Notably, however, olive- and black-backed taxa interbreed (differentiated populations of A. flavinuchus) unless the additional UV distinction is present (A. notabilis vs. A. flavinuchus). Thus, UV-based reflectance can be an essential component of plumage divergence that relates to reproductive isolation, a key attribute of biological species. PMID:15546987

  17. Magnetic Resonance Imaging (MRI)

    MedlinePLUS

    ... the body's organs and structures. MRI uses a magnetic field and radio waves to create detailed pictures of ... things might cause a problem near the strong magnetic field. You won't be able to take your ...

  18. Separating subjective emotion from the perception of emotion-inducing stimuli: an fMRI study.

    PubMed

    Garrett, Amy S; Maddock, Richard J

    2006-10-15

    fMRI was used to dissociate neural responses temporally associated with the subjective experience of emotion from those associated with the perception of emotion-inducing stimuli in order to better define the emotion-related functions of the amygdala, lateral orbital frontal cortex (OFC), and hippocampus. Subjects viewed aversive pictures followed by an extended post-stimulus period of sustained subjective emotion. Brain regions showing activation paralleling the period of sustained subjective emotion were distinguished from those showing activation limited to the period of aversive picture presentation. Behavioral results showed that subjective ratings of emotion remained elevated for 20 s after offset of the aversive pictures. fMRI results showed that viewing aversive pictures activated the amygdala, lateral OFC, and hippocampus. Subjective emotion (present both during and after aversive pictures) was temporally associated with activation in the right lateral OFC and left hippocampus but not the amygdala. Ratings of subjective emotion were correlated with activation in the right lateral OFC and left hippocampus. The results support direct amygdala involvement in emotion perception but suggest that amygdala activation is not temporally associated with subjective emotion that occurs after the offset of emotion-related stimuli. The results are consistent with a general role for the lateral OFC in monitoring or reflecting on internal experience and show that hippocampal activation is sustained during a period of subjective emotion, possibly related to enhanced memory encoding for the aversive pictures. PMID:16908199

  19. Diffusion-Weighted and Gd-EOB-DTPA–Contrast-Enhanced Magnetic Resonance Imaging for Characterization of Tumor Necrosis in an Animal Model

    PubMed Central

    Vossen, Josephina A.; Buijs, Manon; Geschwind, Jean-Francois H.; Liap, Eleni; Ventura, Veronica Prieto; Lee, Kwang Hun; Bluemke, David A; Kamel, Ihab R

    2009-01-01

    Purpose To evaluate the role of diffusion-weighted magnetic resonance imaging (MRI) in determining tumor necrosis and contrast-enhanced MRI using gadoxetic acid disodium (Gd-EOB-DTPA) in determining maximum tumor size measurement and tumor delineation compared with criterion-standard histologic measurements in the rabbit VX2 liver tumor model. Materials and Methods VX2 tumors were implanted in the livers of 13 rabbits. Magnetic resonance imaging was performed using a 1.5-T MRI scanner and an extremity coil. The imaging protocol included T2-weighted fast spin-echo images, 3-dimensional T1-weighted spoiled gradient-echo with and without fat suppression after administration of Gd-EOB-DTPA, and diffusion-weighted echo planar images. Rabbits were killed, and the tumor was harvested and sliced at 4-mm intervals in the axial plane. The MRI parameters evaluated were tumor size, tumor delineation, and tumor apparent diffusion coefficient (ADC) values. Histologic sections were evaluated to quantify tumor necrosis. Results On contrast-enhanced MRI (obtained from 11 rabbits), the mean tumor sizes were 20, 19, and 20 mm in the arterial, portal venous, and delayed phases, respectively. Tumor delineation was most distinguishable in the delayed phase. On diffusion-weighted MRI (acquired in 13 rabbits), the mean tumor ADC value was 1.84 × 10−3 mm2/s. The mean tumor size at pathology was 16 mm. The mean percent necrosis at the tumor’s pathologic condition was 36%. The correlation between ADC value and percent necrosis showed an R value of 0.68. Conclusions Contrast-enhanced MRI using Gd-EOB-DTPA may provide additional information about tumor outline in the liver. More-over, we showed a remarkable correlation between ADC values and tumor necrosis. Thus, diffusion-weighted imaging may be useful to assess tumor necrosis; nevertheless, the search for new modalities remains important. PMID:19638862

  20. MRI in local staging of rectal cancer: an update

    PubMed Central

    Tapan, mit; zbayrak, Mustafa; Tatl?, Servet

    2014-01-01

    Preoperative imaging for staging of rectal cancer has become an important aspect of current approach to rectal cancer management, because it helps to select suitable patients for neoadjuvant chemoradiotherapy and determine the appropriate surgical technique. Imaging modalities such as endoscopic ultrasonography, computed tomography, and magnetic resonance imaging (MRI) play an important role in assessing the depth of tumor penetration, lymph node involvement, mesorectal fascia and anal sphincter invasion, and presence of distant metastatic diseases. Currently, there is no consensus on a preferred imaging technique for preoperative staging of rectal cancer. However, high-resolution phased-array MRI is recommended as a standard imaging modality for preoperative local staging of rectal cancer, with excellent soft tissue contrast, multiplanar capability, and absence of ionizing radiation. This review will mainly focus on the role of MRI in preoperative local staging of rectal cancer and discuss recent advancements in MRI technique such as diffusion-weighted imaging and dynamic contrast-enhanced MRI. PMID:25010367

  1. LDRD 149045 final report distinguishing documents.

    SciTech Connect

    Mitchell, Scott A.

    2010-09-01

    This LDRD 149045 final report describes work that Sandians Scott A. Mitchell, Randall Laviolette, Shawn Martin, Warren Davis, Cindy Philips and Danny Dunlavy performed in 2010. Prof. Afra Zomorodian provided insight. This was a small late-start LDRD. Several other ongoing efforts were leveraged, including the Networks Grand Challenge LDRD, and the Computational Topology CSRF project, and the some of the leveraged work is described here. We proposed a sentence mining technique that exploited both the distribution and the order of parts-of-speech (POS) in sentences in English language documents. The ultimate goal was to be able to discover 'call-to-action' framing documents hidden within a corpus of mostly expository documents, even if the documents were all on the same topic and used the same vocabulary. Using POS was novel. We also took a novel approach to analyzing POS. We used the hypothesis that English follows a dynamical system and the POS are trajectories from one state to another. We analyzed the sequences of POS using support vector machines and the cycles of POS using computational homology. We discovered that the POS were a very weak signal and did not support our hypothesis well. Our original goal appeared to be unobtainable with our original approach. We turned our attention to study an aspect of a more traditional approach to distinguishing documents. Latent Dirichlet Allocation (LDA) turns documents into bags-of-words then into mixture-model points. A distance function is used to cluster groups of points to discover relatedness between documents. We performed a geometric and algebraic analysis of the most popular distance functions and made some significant and surprising discoveries, described in a separate technical report.

  2. How do recovery definitions distinguish recovering individuals?

    PubMed Central

    Witbrodt, Jane; Kaskutas, Lee Ann; Grella, Christine E.

    2015-01-01

    Background Six percent of American adults say they are in recovery from an alcohol or drug problem yet only a scant emergent literature has begun to ask how they define recovery or explored whether there is heterogeneity among their definitions. Methods Secondary analysis of the What Is Recovery? online survey employed Latent Class Analysis (LCA) to identify typologies of study participants based on their actual endorsement of 39 recovery elements and to compare the composition of these typologies in terms of distinguishing personal characteristics. Results A 5-class solution provided the best fit and conceptual representation for the recovery definitions. Classes were labeled 12-Step Traditionalist (n=4912); 12-Step Enthusiast (n=2014); Secular (n=980); Self-Reliant (n=1040); and Atypical (n=382) based on patterns of endorsement of the recovery elements. Abstinence, spiritual, and social interaction elements differentiated the classes most (as did age and recovery duration but to a lesser extent). Although levels and patterns of endorsement to the elements varied by class, a rank-ordering of the top 10 elements indicated that four elements were endorsed by all five classes: being honest with myself, handling negative feelings without using, being able to enjoy life, and process of growth and development. Conclusions The results of the LCA demonstrate the diversity of meanings, and varying degrees of identification with, specific elements of recovery. As others have found, multiple constituents are invested in how recovery is defined and this has ramifications for professional, personal, and cultural processes related to how strategies to promote recovery are implemented. PMID:25630961

  3. Distinguishing dynamical dark matter at the LHC

    NASA Astrophysics Data System (ADS)

    Dienes, Keith R.; Su, Shufang; Thomas, Brooks

    2012-09-01

    Dynamical dark matter (DDM) is a new framework for dark-matter physics in which the dark sector comprises an ensemble of individual component fields which collectively conspire to act in ways that transcend those normally associated with dark matter. Because of its nontrivial structure, this DDM ensemble—unlike most traditional dark-matter candidates—cannot be characterized in terms of a single mass, decay width, or set of scattering cross sections, but must instead be described by parameters which describe the collective behavior of its constituents. Likewise, the components of such an ensemble need not be stable so long as lifetimes are balanced against cosmological abundances across the ensemble as a whole. In this paper, we investigate the prospects for identifying a DDM ensemble at the LHC and for distinguishing such a dark-matter candidate from the candidates characteristic of traditional dark-matter models. In particular, we focus on DDM scenarios in which the component fields of the ensemble are produced at colliders alongside some number of standard-model particles via the decays of additional heavy fields. The invariant-mass distributions of these standard-model particles turn out to possess several unique features that cannot be replicated in most traditional dark-matter models. We demonstrate that in many situations it is possible to differentiate between a DDM ensemble and a traditional dark-matter candidate on the basis of such distributions. Moreover, many of our results also apply more generally to a variety of other extensions of the standard model which involve multiple stable or metastable neutral particles.

  4. Distinguishing between active and passive euthanasia.

    PubMed

    Gert, B; Culver, C M

    1986-02-01

    The standard ways of distinguishing between active and passive euthanasia, act versus omission, and removal of ordinary versus removal of extraordinary care, do not have any clear moral significance. We have used particular aspects of the physician-patient relationship to make a morally significant distinction between active and passive euthanasia. Passive euthanasia is defined as the physician's abiding by the rational valid refusal of life-sustaining treatment of a patient or his surrogate decision-maker. Understanding passive euthanasia in this way makes it clear why, everything else being equal, there is no morally significant difference between discontinuing a treatment and not starting it, for example, taking a patient off a respirator versus not putting him on in the first place. It also makes clear why stopping the feeding and hydration of some patients is not merely morally permissible but is morally required. Patients may make a rational valid refusal of food and fluids just as they may of other kinds of life support, and what patients rationally refuse when competent holds its force when they become incompetent. By basing the distinction between active and passive euthanasia on the universally recognized moral force of a rational valid refusal, we have provided a clear foundation for the moral significance of this distinction. Our way of making the distinction preserves for patients the control over their lives that has sometimes been unjustifiably taken from them. It also eases the burden on doctors who no longer are forced to make use of ad hoc and confused distinctions in which they justifiably have little faith.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3082503

  5. Hopx distinguishes hippocampal from lateral ventricle neural stem cells.

    PubMed

    Li, Deqiang; Takeda, Norifumi; Jain, Rajan; Manderfield, Lauren J; Liu, Feiyan; Li, Li; Anderson, Stewart A; Epstein, Jonathan A

    2015-11-01

    In the adult dentate gyrus (DG) and in the proliferative zone lining the lateral ventricle (LV-PZ), radial glia-like (RGL) cells are neural stem cells (NSCs) that generate granule neurons. A number of molecular markers including glial fibrillary acidic protein (GFAP), Sox2 and nestin, can identify quiescent NSCs in these two niches. However, to date, there is no marker that distinguishes NSC origin of DG versus LV-PZ. Hopx, an atypical homeodomain only protein, is expressed by adult stem cell populations including those in the intestine and hair follicle. Here, we show that Hopx is specifically expressed in RGL cells in the adult DG, and these cells give rise to granule neurons. Assessed by non-stereological quantitation, Hopx-null NSCs exhibit enhanced neurogenesis evident by an increased number of BrdU-positive cells and doublecortin (DCX)-positive neuroblasts. In contrast, Sox2-positive, quiescent NSCs are reduced in the DG of Hopx-null animals and Notch signaling is reduced, as evidenced by reduced expression of Notch targets Hes1 and Hey2, and a reduction of the number of cells expressing the cleaved, activated form of the Notch1 receptor, the Notch intracellular domain (NICD) in Hopx-null DG. Surprisingly, Hopx is not expressed in RGL cells of the adult LV-PZ, and Hopx-expressing cells do not give rise to interneurons of the olfactory bulb (OB). These findings establish that Hopx expression distinguishes NSCs of the DG from those of the LV-PZ, and suggest that Hopx potentially regulates hippocampal neurogenesis by modulating Notch signaling. PMID:26451648

  6. The Topography of Comet Tempel 1 as Distinguished From Images of the Deep Impact Mission

    NASA Astrophysics Data System (ADS)

    Gaeman, Jodi; Farnham, T. L.; A'Hearn, M. F.

    2007-10-01

    In this poster, we present the first elevation measurements of surface features on comet Tempel 1. We report on a project that involves determining the topography of comet Tempel 1, which was impacted during the Deep Impact mission, to provide more detail regarding the comet's surface structure for further analysis of the evolutionary processes cometary bodies undergo. We estimate the topography using data returned from the Deep Impact spacecraft, including Impactor Targeting Sensor (ITS) and Medium Resolution Instrument (MRI) images. Stereo pair images are used as the main method of identifying the relief of the topographical features. There are two sources from which the elevation is derived. The first is the parallax resulting from the different trajectories of the ITS and MRI data; the second is the parallax attributed to the time difference between MRI images. The best resolution, limited by the combination of MRI and ITS data, is about 8 meters per pixel, which limits the range of elevations we can determine. As determining elevation relies on the position of the sun with respect to the comet, the study of the comet's topography also yields some understanding of the material of the comet, as it is necessary to sort those features with natural brightness variations due to composition from those casting shadows. Because data taken during the Deep Impact mission only distinguishably cover a portion of the comet's surface, not all surface features can be analyzed. In this work we determine, map, and then analyze those areas that have sufficient stereo coverage. The determination of the comet's morphology will lead to a better understanding of the stability of its varying structures and thus perhaps the material of which it is composed. This work is funded by NASA's Planetary Data System (PDS) College Student Investigator (CSI) program.

  7. Double Meniscal Ossicle, the First Description: CT and MRI Findings—Different Etiologies

    PubMed Central

    Kumar, Puneeth; Dey, Amit Kumar; Mittal, Kartik; Sharma, Rajaram; Hira, Priya

    2015-01-01

    We present a case of 2 ossicles in the medial meniscus with emphasis on MRI and CT findings. Meniscal ossicle is a rare entity and is quite uncommon on the medial side. By showing the typical signal characteristics and intrameniscal location, MRI can be helpful in distinguishing this from other more clinically significant abnormalities. It should be kept as differential from synovial chondromatosis or sesamoid bones like fabella as management is different for all of these entities. PMID:26788396

  8. MRI of common and uncommon pathologies involving the periportal space: a pictorial essay.

    PubMed

    Lee, Christine U; Glockner, James F

    2016-01-01

    Imaging detection and differential diagnoses of pathology involving the periportal space can be challenging. MRI is a useful technique for assessment of the periportal space since it readily distinguishes normal and abnormal vascular and biliary anatomy, and the excellent soft tissue discrimination allows for detection of subtle lesions. This pictorial essay describes the anatomy of the periportal space and illustrates the MRI appearance of a variety of pathologies that can affect this region. PMID:26830621

  9. Sparse Representation of Brain Aging: Extracting Covariance Patterns from Structural MRI

    PubMed Central

    Su, Longfei; Wang, Lubin; Chen, Fanglin; Shen, Hui; Li, Baojuan; Hu, Dewen

    2012-01-01

    An enhanced understanding of how normal aging alters brain structure is urgently needed for the early diagnosis and treatment of age-related mental diseases. Structural magnetic resonance imaging (MRI) is a reliable technique used to detect age-related changes in the human brain. Currently, multivariate pattern analysis (MVPA) enables the exploration of subtle and distributed changes of data obtained from structural MRI images. In this study, a new MVPA approach based on sparse representation has been employed to investigate the anatomical covariance patterns of normal aging. Two groups of participants (group 1∶290 participants; group 2∶56 participants) were evaluated in this study. These two groups were scanned with two 1.5 T MRI machines. In the first group, we obtained the discriminative patterns using a t-test filter and sparse representation step. We were able to distinguish the young from old cohort with a very high accuracy using only a few voxels of the discriminative patterns (group 1∶98.4%; group 2∶96.4%). The experimental results showed that the selected voxels may be categorized into two components according to the two steps in the proposed method. The first component focuses on the precentral and postcentral gyri, and the caudate nucleus, which play an important role in sensorimotor tasks. The strongest volume reduction with age was observed in these clusters. The second component is mainly distributed over the cerebellum, thalamus, and right inferior frontal gyrus. These regions are not only critical nodes of the sensorimotor circuitry but also the cognitive circuitry although their volume shows a relative resilience against aging. Considering the voxels selection procedure, we suggest that the aging of the sensorimotor and cognitive brain regions identified in this study has a covarying relationship with each other. PMID:22590522

  10. Studies of MRI relaxivities of gadolinium-labeled dendrons

    NASA Astrophysics Data System (ADS)

    Pan, Hongmu; Daniel, Marie-Christine

    2011-05-01

    In cancer detection, imaging techniques have a great importance in early diagnosis. The more sensitive the imaging technique and the earlier the tumor can be detected. Contrast agents have the capability to increase the sensitivity in imaging techniques such as magnetic resonance imaging (MRI). Until now, gadolinium-based contrast agents are mainly used for MRI, and show good enhancement. But improvement is needed for detection of smaller tumors at the earliest stage possible. The dendrons complexed with Gd(DOTA) were synthesized and evaluated as a new MRI contrast agent. The longitudinal and transverse relaxation effects were tested and compared with commercial drug Magnevist, Gd(DTPA).

  11. Tryptophan PET-defined gross tumor volume offers better coverage of initial progression than standard MRI-based planning in glioblastoma patients

    PubMed Central

    Kamson, David Olayinka; Snyder, Michael; Kim, Harold; Robinette, Natasha L.; Mittal, Sandeep; Juhsz, Csaba

    2014-01-01

    Objective Glioblastoma is an infiltrative malignancy that tends to extend beyond the MRI-defined tumor volume. We utilized positron emission tomography (PET) imaging with the radiotracer alpha-[11C]methyl-L -tryptophan (AMT) to develop a reliable high-risk gross tumor volume (HR-GTV) method for delineation of glioblastoma. AMT can detect solid tumor mass and tumoral brain infiltration by increased tumoral tryptophan transport and metabolism via the immunosuppressive kynurenine pathway. Methods We reviewed all patients in our database with histologically proven glioblastoma who underwent preoperative AMT-PET scan prior to surgery and chemoradiation. Treated radiotherapy volumes were derived from the simulation CT with MRI fusion. High-GTV with contrast enhanced T1-weighted MRI alone (GTVMRI) was defined as the postoperative cavity plus any residual area of enhancement on postcontrast T1-weighted images. AMT-PET images were retrospectively fused to the simulation CT, and a high-risk GTVs generated by both AMT-PET alone (GTVAMT) was defined using a threshold previously established to distinguish tumor tissue from peritumoral edema. A composite volume of MRI and AMT tumor volume was also created (combination of MRI fused with AMT-PET data; GTVMRI+AMT). In patients with definitive radiographic progression, follow-up MRI demonstrating initial tumor progression was fused with the pretreatment images and a progression volume was contoured. The coverage of the progression volume by GTVMRI, GTVAMT, and GTVMRI+AMT was determined and compared using the Wilcoxons signed-rank test. Results Eleven patients completed presurgical AMT-PET scan, seven of whom had progressive disease after initial therapy. GTVMRI (mean, 50.2 cm3) and GTVAMT (mean, 48.9 cm3) were not significantly different. Mean concordance index of the volumes was 3915 %. Coverage of the initial recurrence volume by HR-GTVMRI (mean, 52 %) was inferior to both GTVAMT (mean, 68 %; p =0.028) and GTVMRI+AMT (mean 73 %; p =0.018). The AMT-PET-exclusive coverage was up to 41 % of the recurrent volume. There was a tendency towards better recurrence coverage with GTVMRI+AMT than with GTVAMT alone (p =0.068). Addition of 5 mm concentric margin around GTVMRI, GTVAMT, and GTVMRI+AMT would have completely covered the initial progression volume in 14, 57, and 71 % of the patients, respectively. Conclusion We found that a GTV defined by AMT-PET produced similar volume, but superior recurrence coverage than the treated standard MRI-determined volume. A prospective study is necessary to fully determine the usefulness of AMT-PET for volume definition in glioblastoma radiotherapy planning. PMID:25414765

  12. Role Of Cardiac Mri In The Assessment Of Nonischemic Cardiomyopathies

    PubMed Central

    Nabi, Faisal

    2013-01-01

    In this review, we will highlight the role of late gadolinium enhancement, along with other strengths available by cardiac MRI, in determining the underlying etiology of various nonischemic cardiomyopathies. Furthermore, we will also emphasize how late gadolinium enhancement may serve as a novel risk stratification tool to further impact patient care. PMID:24066198

  13. Microtesla MRI with dynamic nuclear polarization

    PubMed Central

    Zotev, Vadim S.; Owens, Tuba; Matlashov, Andrei N.; Savukov, Igor M.; Gomez, John J.; Espy, Michelle A.

    2010-01-01

    Magnetic resonance imaging at microtesla fields is a promising imaging method that combines the pre-polarization technique and broadband signal reception by superconducting quantum interference device (SQUID) sensors to enable in vivo MRI at microtesla-range magnetic fields similar in strength to the Earth magnetic field. Despite significant advances in recent years, the potential of microtesla MRI for biomedical imaging is limited by its insufficient signal-to-noise ratio due to a relatively low sample polarization. Dynamic nuclear polarization (DNP) is a widely used approach that allows polarization enhancement by two-four orders of magnitude without an increase in the polarizing field strength. In this work, the first implementation of microtesla MRI with Overhauser DNP and SQUID signal detection is described. The first measurements of carbon-13 NMR spectra at microtesla fields are also reported. The experiments were performed at the measurement field of 96 microtesla, corresponding to Larmor frequency of 4 kHz for protons and 1 kHz for carbon-13. The Overhauser DNP was carried out at 3.5 5.7 mT field using rf irradiation at 120 MHz. Objects for imaging included water phantoms and a cactus plant. Aqueous solutions of metabolically relevant sodium bicarbonate, pyruvate, alanine, and lactate, labeled with carbon-13, were used for NMR studies. All the samples were doped with TEMPO free radicals. The Overhauser DNP enabled nuclear polarization enhancement by factor as high as ?95 for protons and as high as ?200 for carbon-13, corresponding to thermal polarizations at 0.33 T and 1.1 T fields, respectively. These results demonstrate that SQUID-based microtesla MRI can be naturally combined with Overhauser DNP in one system, and that its signal-to-noise performance is greatly improved in this case. They also suggest that microtesla MRI can become an efficient tool for in vivo imaging of hyperpolarized carbon-13, produced by the low-temperature dissolution DNP. PMID:20843715

  14. Microtesla MRI with dynamic nuclear polarization

    NASA Astrophysics Data System (ADS)

    Zotev, Vadim S.; Owens, Tuba; Matlashov, Andrei N.; Savukov, Igor M.; Gomez, John J.; Espy, Michelle A.

    2010-11-01

    Magnetic resonance imaging at microtesla fields is a promising imaging method that combines the pre-polarization technique and broadband signal reception by superconducting quantum interference device (SQUID) sensors to enable in vivo MRI at microtesla-range magnetic fields similar in strength to the Earth magnetic field. Despite significant advances in recent years, the potential of microtesla MRI for biomedical imaging is limited by its insufficient signal-to-noise ratio due to a relatively low sample polarization. Dynamic nuclear polarization (DNP) is a widely used approach that allows polarization enhancement by 2-4 orders of magnitude without an increase in the polarizing field strength. In this work, the first implementation of microtesla MRI with Overhauser DNP and SQUID signal detection is described. The first measurements of carbon-13 NMR spectra at microtesla fields are also reported. The experiments were performed at the measurement field of 96 ?T, corresponding to Larmor frequency of 4 kHz for protons and 1 kHz for carbon-13. The Overhauser DNP was carried out at 3.5-5.7 mT fields using rf irradiation at 120 MHz. Objects for imaging included water phantoms and a cactus plant. Aqueous solutions of metabolically relevant sodium bicarbonate, pyruvate, alanine, and lactate, labeled with carbon-13, were used for NMR studies. All the samples were doped with TEMPO free radicals. The Overhauser DNP enabled nuclear polarization enhancement by factor as large as -95 for protons and as large as -200 for carbon-13, corresponding to thermal polarizations at 0.33 T and 1.1 T fields, respectively. These results demonstrate that SQUID-based microtesla MRI can be naturally combined with Overhauser DNP in one system, and that its signal-to-noise performance is greatly improved in this case. They also suggest that microtesla MRI can become an efficient tool for in vivo imaging of hyperpolarized carbon-13, produced by low-temperature dissolution DNP.

  15. Techniques for fast stereoscopic MRI.

    PubMed

    Guttman, M A; McVeigh, E R

    2001-08-01

    Stereoscopic MRI can impart 3D perception with only two image acquisitions. This economy over standard multiplanar 3D volume renderings allows faster frame rates, which are needed for real-time imaging applications. Real-time 3D perception may enhance the appreciation of complex anatomical structures, and may improve hand-eye coordination while manipulating a medical device during an image-guided interventional procedure. To this goal, a system is being developed to acquire and display stereoscopic MR images in real-time. A clinically used, fast gradient-recalled echo-train sequence has been modified to produce stereo image pairs. Features have been added for depth cueing, view sharing, and bulk signal suppression. A workstation was attached to a clinical MR scanner for fast data extraction, image reconstruction and stereoscopic image display. PMID:11477636

  16. Radiotherapy planning using MRI

    NASA Astrophysics Data System (ADS)

    Schmidt, Maria A.; Payne, Geoffrey S.

    2015-11-01

    The use of magnetic resonance imaging (MRI) in radiotherapy (RT) planning is rapidly expanding. We review the wide range of image contrast mechanisms available to MRI and the way they are exploited for RT planning. However a number of challenges are also considered: the requirements that MR images are acquired in the RT treatment position, that they are geometrically accurate, that effects of patient motion during the scan are minimized, that tissue markers are clearly demonstrated, that an estimate of electron density can be obtained. These issues are discussed in detail, prior to the consideration of a number of specific clinical applications. This is followed by a brief discussion on the development of real-time MRI-guided RT.

  17. Magnetic Resonance Imaging (MRI): Brain

    MedlinePLUS

    ... All About Food Allergies Magnetic Resonance Imaging (MRI): Brain KidsHealth > For Parents > Magnetic Resonance Imaging (MRI): Brain ... child may be given headphones to listen to music or earplugs to block the noise, and will ...

  18. MRI in thorotrastosis.

    PubMed

    Ono, N; Hirai, K; Ijyuin, H; Itano, S; Noguchi, H; Sakata, K; Aoki, Y; Aritaka, T; Abe, H; Tanikawa, K

    1995-01-01

    Magnetic resonance imaging (MRI) and computed tomography (CT) were performed in four patients with thorotrastosis. On CT scan, Thorotrast (thorium oxide) deposition was shown as high-density areas in the liver and spleen and the abdominal lymph nodes. These deposits were not found on MRIs. Splenic volume was significantly small due to atrophy. The contrast-noise ratio in the spleen on T1-weighted images was significantly lower. Thorotrast deposition does not affect MRI appearance; therefore it may be useful for the early detection of malignant tumors as a complication of thorotrastosis. PMID:8564863

  19. Echocardiographic criteria to distinguish reversible from irreversible myocardial ischaemia.

    PubMed

    Corday, E; Hajduczki, I; O'Byrne, G T; Kar, S; Areeda, J; Corday, S R

    1988-04-01

    This treatise reviews two-dimensional echocardiographic criteria which have been developed to describe and distinguish reversible vs irreversible myocardial ischaemia. It also discusses the new pathophysiologic concepts such as 'hibernating' and 'decapitated' myocardium, and also 'reperfusion injury' and 'stunned' myocardium, complications which may supervene following reperfusion of jeopardized ischaemic myocardium. Computerized regional and global wall-motion analysis is now usually measured from enhanced endocardial edges. Provocative interventions can contribute information regarding viability of jeopardized ischaemic regions by testing contractile response of the myocardium to afterload reducing agents such as nitroglycerine or nitroprusside. They can also validate viability by demonstrating that post-extrasystolic beats can still cause potentiation. Ultrasonic contrast washout half-life of the myocardium which is compromised by stenotic coronary arteries provides a promising method for supplying information about the coronary perfusion defects and flow reserve. The decrease in global or regional ejection fraction following exercise echocardiography may show if jeopardized ischaemic myocardium is irreversibly damaged. A new hypercontractility phenomenon is described following brief coronary occlusions such as during percutaneous transluminal angioplasty, or after sudden release of angiospasm, and this should be considered a sign of viability. Increase in end-diastolic wall thickness and echo amplitudes immediately after reperfusion of ischaemic segments is often associated with reversibly damaged myocardium. PMID:3134240

  20. Acoustic variability and distinguishability among mouse ultrasound vocalizations

    NASA Astrophysics Data System (ADS)

    Liu, Robert C.; Miller, Kenneth D.; Merzenich, Michael M.; Schreiner, Christoph E.

    2003-12-01

    Auditory neurobiology has benefited significantly from ethological approaches using acoustic communication signals. Developing an ethological model in a genetically manipulable system such as the mouse would enhance the ability to investigate the processing, learning, and recognition of sounds. Characterizing the basic acoustic structure of mouse vocalizations would help lay a foundation for such a future study. Towards this goal, ultrasound vocalizations emitted by isolated mouse pups and pairs of adult males and females have been digitally recorded and examined. Previous work suggests that these calls may have communicative significance. An analysis of the natural variability in their spectral content, median frequency, duration, and repetition period reveals acoustic structure that could be used for recognizing the calls. Other parameters, like the rate of frequency modulation, may also be informative, but have not been examined. Pup isolation calls develop systematically between postnatal day 5 and 12 towards a more stereotyped vocalization-contracting from a wide range of values into narrower clusters of frequency and duration, and shifting from longer to shorter repetition periods. Most significantly, pup isolation and adult encounter calls fall into two distinct spectral and temporal categories, making it possible for a receiver to acoustically distinguish between them, and to potentially categorically perceive them along those dimensions.

  1. Fluorinated Aromatic Amino Acids Distinguish Cation-? Interactions from Membrane Insertion.

    PubMed

    He, Tao; Gershenson, Anne; Eyles, Stephen J; Lee, Yan-Jiun; Liu, Wenshe R; Wang, Jiangyun; Gao, Jianmin; Roberts, Mary F

    2015-07-31

    Cation-? interactions, where protein aromatic residues supply ? systems while a positive-charged portion of phospholipid head groups are the cations, have been suggested as important binding modes for peripheral membrane proteins. However, aromatic amino acids can also insert into membranes and hydrophobically interact with lipid tails. Heretofore there has been no facile way to differentiate these two types of interactions. We show that specific incorporation of fluorinated amino acids into proteins can experimentally distinguish cation-? interactions from membrane insertion of the aromatic side chains. Fluorinated aromatic amino acids destabilize the cation-? interactions by altering electrostatics of the aromatic ring, whereas their increased hydrophobicity enhances membrane insertion. Incorporation of pentafluorophenylalanine or difluorotyrosine into a Staphylococcus aureus phosphatidylinositol-specific phospholipase C variant engineered to contain a specific PC-binding site demonstrates the effectiveness of this methodology. Applying this methodology to the plethora of tyrosine residues in Bacillus thuringiensis phosphatidylinositol-specific phospholipase C definitively identifies those involved in cation-? interactions with phosphatidylcholine. This powerful method can easily be used to determine the roles of aromatic residues in other peripheral membrane proteins and in integral membrane proteins. PMID:26092728

  2. Development of hyperpolarized noble gas MRI

    NASA Astrophysics Data System (ADS)

    Albert, M. S.; Balamore, D.

    1998-02-01

    Magnetic resonance imaging using the MR signal from hyperpolarized noble gases 129Xe and 3He may become an important new diagnostic technique. Alex Pines (adapting the hyperpolarization technique pioneered by William Happer) presented MR spectroscopy studies using hyperpolarized 129Xe. The current authors recognized that the enormous enhancement in the detectability of 129Xe, promised by hyperpolarization, would solve the daunting SNR problems impeding their attempts to use 129Xe as an in vivo MR probe, especially in order to study the action of general anesthetics. It was hoped that hyperpolarized 129Xe MRI would yield resolutions equivalent to that achievable with conventional 1H 2O MRI, and that xenon's solubility in lipids would facilitate investigations of lipid-rich tissues that had as yet been hard to image. The publication of hyperpolarized 129Xe images of excised mouse lungs heralded the emergence of hyperpolarized noble-gas MRI. Using hyperpolarized 3He, researchers have obtained images of the lung gas space of guinea pigs and of humans. Lung gas images from patients with pulmonary disease have recently been reported. 3He is easier to hyperpolarize than 129Xe, and it yields a stronger MR signal, but its extremely low solubility in blood precludes its use for the imaging of tissue. Xenon, however, readily dissolves in blood, and the T1 of dissolved 129Xe is long enough for sufficient polarization to be carried by the circulation to distal tissues. Hyperpolarized 129Xe dissolved-phase tissue spectra from the thorax and head of rodents and humans have been obtained, as have chemical shift 129Xe images from the head of rats. Lung gas 129Xe images of rodents, and more recently of humans, have been reported. Hyperpolarized 129Xe MRI (HypX-MRI) may elucidate the link between the structure of the lung and its function. The technique may also be useful in identifying ventilation-perfusion mismatch in patients with pulmonary embolism, in staging and tracking the success of therapeutic approaches in patients with chronic obstructive airway diseases, and in identifying candidates for lung transplantation or reduction surgery. The high lipophilicity of xenon may allow MR investigations of the integrity and function of excitable lipid membranes. Eventually, HypX-MRI may permit better imaging of the lipid-rich structures of the brain. Cortical brain function is one perfusion-dependent phenomena that may be explored with hyperpolarized 129Xe MR. This leads to the exciting possibility of conducting hyperpolarized 129Xe functional MRI (HypX-fMRI) studies.

  3. Polynomial transformation for MRI feature extraction

    NASA Astrophysics Data System (ADS)

    Soltanian-Zadeh, Hamid; Kharrat, Mahmood; Peck, Donald J.

    2001-07-01

    We present a non-linear (polynomial) transformation to minimize scattering of data points around normal tissue clusters in a normalized MRI feature space, in which normal tissues are clustered around pre-specified target positions. This transformation is motivated by non-linear relationship between MRI pixel intensities and intrinsic tissue parameters (e.g., T1, T2, PD). To determine scattering amount, we use ratio of summation of within-class distances fro clusters to summation of their between-class distances. We find the transformation by minimizing the scattering amount. Next, we generate a 3D visualization of the MRI feature space and define regions of interest (ROI's) on clusters seen for normal and abnormal tissues. We use these ROI's to estimate signature vectors (cluster centers). Finally, we use the signature vectors for segmenting and characterizing tissues. We used simulation, phantom, and brain MRI to evaluate the polynomial transformation and compare it to the linear transformation. In all studies, we were able to identify clusters for normal and abnormal tissues and segment the images. Compared to the linear method, the non-linear approach yields enhanced clustering properties and better separation of normal and abnormal tissues. ON the other hand, the linear transformation is more appropriate than the non-linear method for capturing partial volume information.

  4. MRI driven magnetic microswimmers

    PubMed Central

    Jakab, Pter; Szkely, Gbor; Hata, Nobuhiko

    2013-01-01

    Capsule endoscopy is a promising technique for diagnosing diseases in the digestive system. Here we design and characterize a miniature swimming mechanism that uses the magnetic fields of the MRI for both propulsion and wireless powering of the capsule. Our method uses both the static and the radio frequency (RF) magnetic fields inherently available in MRI to generate a propulsive force. Our study focuses on the evaluation of the propulsive force for different swimming tails and experimental estimation of the parameters that influence its magnitude. We have found that an approximately 20 mm long, 5 mm wide swimming tail is capable of producing 0.21 mN propulsive force in water when driven by a 20 Hz signal providing 0.85 mW power and the tail located within the homogeneous field of a 3 T MRI scanner. We also analyze the parallel operation of the swimming mechanism and the scanner imaging. We characterize the size of artifacts caused by the propulsion system. We show that while the magnetic micro swimmer is propelling the capsule endoscope, the operator can locate the capsule on the image of an interventional scene without being obscured by significant artifacts. Although this swimming method does not scale down favorably, the high magnetic field of the MRI allows self propulsion speed on the order of several millimeter per second and can propel an endoscopic capsule in the stomach. PMID:22037673

  5. Phantom for Diffusion MRI

    Cancer.gov

    Combining a Diffusion MRI phantom with a resolution phantom would allow the same device to be used to calibrate an MR scanner''s image quality and the accuracy and precision of its diffusion measurements. This would be useful particularly for Radiological QA and for use in assuring data quality in longitudinal and multi-subject studies.

  6. MRI of intact plants.

    PubMed

    Van As, Henk; Scheenen, Tom; Vergeldt, Frank J

    2009-01-01

    Nuclear magnetic resonance imaging (MRI) is a non-destructive and non-invasive technique that can be used to acquire two- or even three-dimensional images of intact plants. The information within the images can be manipulated and used to study the dynamics of plant water relations and water transport in the stem, e.g., as a function of environmental (stress) conditions. Non-spatially resolved portable NMR is becoming available to study leaf water content and distribution of water in different (sub-cellular) compartments. These parameters directly relate to stomatal water conductance, CO(2) uptake, and photosynthesis. MRI applied on plants is not a straight forward extension of the methods discussed for (bio)medical MRI. This educational review explains the basic physical principles of plant MRI, with a focus on the spatial resolution, factors that determine the spatial resolution, and its unique information for applications in plant water relations that directly relate to plant photosynthetic activity. PMID:19711192

  7. FDG and (82)Rb PET/MRI features of brain metastasis of breast cancer.

    PubMed

    Lu, Yang

    2015-06-01

    A 64-year-old woman with stage IV breast cancer underwent an FDG and Rb PET brain studies. The PET brain images were fused with MRI brain T1 post-contrast images. The known enhancing left superoposterior frontal brain metastasis is positive on both FDG Rb PET/MRI images. The Rb PET/MRI showed better target-to-noise ratio, but showed nonspecific uptake in the superior sagittal sinus. PMID:25674864

  8. Charles L. Brewer Award for Distinguished Teaching of Psychology

    ERIC Educational Resources Information Center

    American Psychologist, 2009

    2009-01-01

    The American Psychological Foundation (APF) Charles L. Brewer Distinguished Teaching of Psychology Award recognizes an outstanding career contribution to the teaching of psychology. The 2009 recipient of the Distinguished Teaching Award is William Buskist. Dorothy W. Cantor, president of the APF, will present the APF Teaching Award at the 117th

  9. Distinguishability of Biological Material Using Ultraviolet Multi-Spectral Fluorescence

    SciTech Connect

    Gray, P.C.; Heinen, R.J.; Rigdon, L.D.; Rosenthal, S.E.; Shokair, I.R.; Siragusa, G.R.; Tisone, G.C.; Wagner, J.S.

    1998-10-14

    Recent interest in the detection and analysis of biological samples by spectroscopic methods has led to questions concerning the degree of distinguishability and biological variability of the ultraviolet (W) fluorescent spectra from such complex samples. We show that the degree of distinguishability of such spectra is readily determined numerically.

  10. 29 CFR 779.328 - Retail and wholesale distinguished.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Retail and wholesale distinguished. 779.328 Section 779.328... AS APPLIED TO RETAILERS OF GOODS OR SERVICES Exemptions for Certain Retail or Service Establishments recognized As Retail in the Particular Industry 779.328 Retail and wholesale distinguished. (a)...

  11. Excellence in Teacher Education. 1973 Distinguished Achievement Awards Program.

    ERIC Educational Resources Information Center

    American Association of Colleges for Teacher Education, Washington, DC.

    The State University of New York College of Cortland received the 1973 Distinguished Achievement Award for its Project Change, a performance-based early childhood teacher education program. Also cited for distinguished achievement were a) Teachers College of Ball State University, Indiana for an experimental program designed to include

  12. Liberating the Publications of a Distinguished Scholar: A Pilot Project

    ERIC Educational Resources Information Center

    Kelly, Julie

    2014-01-01

    Many distinguished scholars published the primary corpus of their work before the advent of online journals, which makes it more challenging to access. Upon being approached by a distinguished Emeritus Professor seeking advice about getting his work posted online, librarians at the University of Minnesota worked to gain copyright permissions to

  13. 32 CFR 22.215 - Distinguishing grants and cooperative agreements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Distinguishing grants and cooperative agreements... Appropriate Instrument 22.215 Distinguishing grants and cooperative agreements. (a) Once a grants officer judges, in accordance with 22.205 and 22.210, that either a grant or cooperative agreement is...

  14. Distinguishing between Knowledge and Beliefs: Students' Epistemic Criteria for Differentiating

    ERIC Educational Resources Information Center

    Boldrin, Angela; Mason, Lucia

    2009-01-01

    "I believe that he/she is telling the truth", "I know about the solar system": what epistemic criteria do students use to distinguish between knowledge and beliefs? If knowing and believing are conceptually distinguishable, do students of different grade levels use the same criteria to differentiate the two constructs? How do students understand…

  15. 28 CFR 301.318 - Civilian compensation laws distinguished.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Civilian compensation laws distinguished... Civilian compensation laws distinguished. The Inmate Accident Compensation system is not obligated to... under civilian workmen's compensation laws in that hospitalization is usually completed prior to...

  16. MRI features of breast lymphoma: preliminary experience in seven cases

    PubMed Central

    Wang, Lijun; Wang, Dengbin; Chai, Weimin; Fei, Xiaochun; Luo, Ran; Li, Xiaoxiao

    2015-01-01

    PURPOSE We aimed to evaluate the imaging features of breast lymphoma using magnetic resonance imaging (MRI). METHODS This retrospective study consisted of seven patients with pathologically confirmed breast lymphoma. The breast lymphomas were primary in six patients and secondary in one patient. All patients underwent preoperative dynamic contrast-enhanced MRI and one underwent additional diffusion-weighted imaging (DWI) with a b value of 600 s/mm2. Morphologic characteristics, enhancement features, and apparent diffusion coefficient (ADC) values were reviewed. RESULTS On MRI, three patients presented with a single mass, one with two masses, two with multiple masses, and one with a single mass and a contralateral focal enhancement. The MRI features of the eight biopsied masses in seven patients were analyzed. On MRI, the margins were irregular in six masses (75%) and spiculated in two (25%). Seven masses (87.5%) displayed homogeneous internal enhancement, while one (12.5%) showed rim enhancement. Seven masses (87.5%) showed a washout pattern and one (12.5%) showed a plateau pattern. The penetrating vessel sign was found in two masses (25%). One patient with two masses underwent DWI. Both masses showed hyperintense signal on DWI with ADC values of 0.86710?3 mm2/s and 0.73210?3 mm2/s, respectively. CONCLUSION Breast lymphoma commonly presents as a homogeneously enhancing mass with irregular margins and displays a washout curve pattern on dynamic MRI. A low ADC value may also indicate a possible diagnosis of breast lymphoma. PMID:26380896

  17. Evolving role of MRI in Crohn's disease.

    PubMed

    Yacoub, Joseph H; Obara, Piotr; Oto, Aytekin

    2013-06-01

    MR enterography is playing an evolving role in the evaluation of small bowel Crohn's disease (CD). Standard MR enterography includes a combination of rapidly acquired T2 sequence, balanced steady-state acquisition, and contrast enhanced T1-weighted gradient echo sequence. The diagnostic performance of these sequences has been shown to be comparable, and in some respects superior, to other small bowel imaging modalities. The findings of CD on MR enterography have been well described in the literature. New and emerging techniques such as diffusion-weighted imaging (DWI), dynamic contrast enhanced MRI (DCE-MRI), cinematography, and magnetization transfer, may lead to improved accuracy in characterizing the disease. These advanced techniques can provide quantitative parameters that may prove to be useful in assessing disease activity, severity, and response to treatment. In the future, MR enterography may play an increasing role in management decisions for patients with small bowel CD; however, larger studies are needed to validate these emerging MRI parameters as imaging biomarkers. PMID:23712842

  18. A unique MRI presentation of fungal infection in the brain.

    PubMed

    Khan, Muhammad Bilal Salman; Shafqat, Saad; Enam, Syed Ather

    2014-11-01

    Fungal infections of CNS are common in certain geographic locations. MRI with or without contrast is a useful prediagnostic tool. However, the findings may sometimes be misleading. In this case report, the authors present unusual imaging findings in the MRI of fungal infection in an immunocompetent host, whereby hyper-intense signals were seen on T2-weighted images and patchy post-contrast enhancement was observed with surrounding edema. These findings were suggestive of a neoplastic lesion but it was identified as aspergillosis on subsequent histopathology. This unusual MRI finding of CNS highlights the need to consider fungal infection as a differential diagnosis of all mass lesions on MRI, irrespective of their signal characteristics. PMID:25518777

  19. Distinguishing Between Site Waste, Natural, and Other Sources of Contamination at Uranium and Thorium Contaminated Sites - 12274

    SciTech Connect

    Hays, David C.

    2012-07-01

    Uranium and thorium processing and milling sites generate wastes (source, byproduct, or technically enhanced naturally occurring material), that contain contaminants that are similar to naturally occurring radioactive material deposits and other industry wastes. This can lead to mis-identification of other materials as Site wastes. A review of methods used by the US Army Corps of Engineers and the Environmental Protection Agency to distinguish Site wastes from potential other sources, enhanced materials, and natural deposits, at three different thorium mills was conducted. Real case examples demonstrate the importance of understanding the methods of distinguishing wastes. Distinguishing between Site wastes and enhanced Background material can be facilitated by establishing and applying a formal process. Significant project cost avoidance may be realized by distinguishing Site wastes from enhanced NORM. Collection of information on other potential sources of radioactive material and physical information related to the potential for other radioactive material sources should be gathered and reported in the Historical Site Assessment. At a minimum, locations of other such information should be recorded. Site decision makers should approach each Site area with the expectation that non site related radioactive material may be present and have a process in place to distinguish from Site and non Site related materials. (authors)

  20. Item Memory, Context Memory and the Hippocampus: fMRI Evidence

    ERIC Educational Resources Information Center

    Rugg, Michael D.; Vilberg, Kaia L.; Mattson, Julia T.; Yu, Sarah S.; Johnson, Jeffrey D.; Suzuki, Maki

    2012-01-01

    Dual-process models of recognition memory distinguish between the retrieval of qualitative information about a prior event (recollection), and judgments of prior occurrence based on an acontextual sense of familiarity. fMRI studies investigating the neural correlates of memory encoding and retrieval conducted within the dual-process framework have

  1. Item Memory, Context Memory and the Hippocampus: fMRI Evidence

    ERIC Educational Resources Information Center

    Rugg, Michael D.; Vilberg, Kaia L.; Mattson, Julia T.; Yu, Sarah S.; Johnson, Jeffrey D.; Suzuki, Maki

    2012-01-01

    Dual-process models of recognition memory distinguish between the retrieval of qualitative information about a prior event (recollection), and judgments of prior occurrence based on an acontextual sense of familiarity. fMRI studies investigating the neural correlates of memory encoding and retrieval conducted within the dual-process framework have…

  2. Automated localization of breast cancer in DCE-MRI.

    PubMed

    Gubern-Mérida, Albert; Martí, Robert; Melendez, Jaime; Hauth, Jakob L; Mann, Ritse M; Karssemeijer, Nico; Platel, Bram

    2015-02-01

    Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is increasingly being used for the detection and diagnosis of breast cancer. Compared to mammography, DCE-MRI provides higher sensitivity, however its specificity is variable. Moreover, DCE-MRI data analysis is time consuming and depends on reader expertise. The aim of this work is to propose a novel automated breast cancer localization system for DCE-MRI. Such a system can be used to support radiologists in DCE-MRI analysis by marking suspicious areas. The proposed method initially corrects for motion artifacts and segments the breast. Subsequently, blob and relative enhancement voxel features are used to locate lesion candidates. Finally, a malignancy score for each lesion candidate is obtained using region-based morphological and kinetic features computed on the segmented lesion candidate. We performed experiments to compare the use of different classifiers in the region classification stage and to study the effect of motion correction in the presented system. The performance of the algorithm was assessed using free-response operating characteristic (FROC) analysis. For this purpose, a dataset of 209 DCE-MRI studies was collected. It is composed of 95 DCE-MRI studies with 105 breast cancers (55 mass-like and 50 non-mass-like malignant lesions) and 114 DCE-MRI studies from women participating in a screening program which were diagnosed to be normal. At 4 false positives per normal case, 89% of the breast cancers (91% and 86% for mass-like and non-mass-like malignant lesions, respectively) were correctly detected. PMID:25532510

  3. Brain MRI findings in Wernicke encephalopathy.

    PubMed

    Wicklund, Meredith R; Knopman, David S

    2013-08-01

    A 71-year-old woman with myelofibrosis on chemotherapy experienced an acute illness with nausea, vomiting, and diarrhea. Two weeks later, she developed an acute confusional state characterized by disorientation and fluctuating alertness with normal speech and language. Her neurologic examination demonstrated an upper motor neuron pattern of right hemiparesis. She reported double vision though ophthalmoparesis was not appreciated. Her gait was normal. While hospitalized, she developed generalized tonic-clonic seizures. Brain MRI revealed a small area of restricted diffusion of the left precentral gyrus (figure). She was diagnosed with a stroke with secondary seizures; however, as the confusional state resolved, she developed profound retrograde and anterograde amnesia. Review of the brain MRI showed high T2 signal in the medial thalamus and contrast enhancement of the mamillary bodies; a diagnosis of Wernicke-Korsakoff syndrome was entertained and she was started on thiamine replacement. The encephalopathy and hemiparesis resolved though she remains severely amnestic. PMID:24195023

  4. MRI of the penis

    PubMed Central

    Kirkham, A

    2012-01-01

    MRI of the penis is an expensive test that is not always superior to clinical examination or ultrasound. However, it shows many of the important structures, and in particular the combination of tumescence from intracavernosal alprostadil, and high-resolution T2 sequences show the glans, corpora and the tunica albuginea well. In this paper we summarise the radiological anatomy and discuss the indications for MRI. For penile cancer, it may be useful in cases where the local stage is not apparent clinically. In priapism, it is an emerging technique for assessing corporal viability, and in fracture it can in most cases make the diagnosis and locate the injury. In some cases of penile fibrosis and Peyronie's disease, it may aid surgical planning, and in complex pelvic fracture may replace or augment conventional urethrography. It is an excellent investigation for the malfunctioning penile prosthesis. PMID:23118102

  5. Distinguishing bias from sensitivity effects in multialternative detection tasks

    PubMed Central

    Sridharan, Devarajan; Steinmetz, Nicholas A.; Moore, Tirin; Knudsen, Eric I.

    2014-01-01

    Studies investigating the neural bases of cognitive phenomena increasingly employ multialternative detection tasks that seek to measure the ability to detect a target stimulus or changes in some target feature (e.g., orientation or direction of motion) that could occur at one of many locations. In such tasks, it is essential to distinguish the behavioral and neural correlates of enhanced perceptual sensitivity from those of increased bias for a particular location or choice (choice bias). However, making such a distinction is not possible with established approaches. We present a new signal detection model that decouples the behavioral effects of choice bias from those of perceptual sensitivity in multialternative (change) detection tasks. By formulating the perceptual decision in a multidimensional decision space, our model quantifies the respective contributions of bias and sensitivity to multialternative behavioral choices. With a combination of analytical and numerical approaches, we demonstrate an optimal, one-to-one mapping between model parameters and choice probabilities even for tasks involving arbitrarily large numbers of alternatives. We validated the model with published data from two ternary choice experiments: a target-detection experiment and a length-discrimination experiment. The results of this validation provided novel insights into perceptual processes (sensory noise and competitive interactions) that can accurately and parsimoniously account for observers' behavior in each task. The model will find important application in identifying and interpreting the effects of behavioral manipulations (e.g., cueing attention) or neural perturbations (e.g., stimulation or inactivation) in a variety of multialternative tasks of perception, attention, and decision-making. PMID:25146574

  6. Markers of Cochlear Inflammation Using MRI

    PubMed Central

    Floc’h, Johann Le; Tan, Winston; Telang, Ravindra S.; Vlajkovic, Srdjan M.; Nuttall, Alfred; Rooney, William D.; Pontré, Beau; Thorne, Peter R.

    2014-01-01

    Purpose: To quantify spatial and temporal inflammation-induced changes in vascular permeability and macrophage infiltration in guinea-pig (GP) cochlea using MRI. Materials and Methods: GPs were injected with lipopolysaccharide (LPS) to induce cochlear inflammation. One group was injected with a gadolinium based contrast agent (GBCA) and dynamic contrast enhanced (DCE)-MRI was performed at 4, 7, and 10 days after LPS treatment. A two-compartment pharmacokinetic model was used to determine the apparent rate constant of GBCA extravasation (Ktrans). A second group was injected with ultrasmall superparamagnetic iron oxide particles (USPIOs) and studied at 2, 3, and 7 days after LPS treatment to detect tissue USPIO uptake and correlate with histology. For both groups, control GPs were scanned similarly. Results: The signal enhancement increased substantially and more rapidly at day 4 in LPS-treated than in control cochlea shortly following GBCA injection. Ktrans of LPS-treated cochlea was maximum on day 4 at 0.0218±0.0032 min−1 and then decreased to control level at 0.0036±0.0004 min−1 by day 10. In the second group, the relative signal intensity and T2 in cochlear perilymphatic spaces on day 2 decreased, on average, by 54% and 45%, respectively, compared with baseline and then remained under control levels by day 7. This suggests the infiltration of inflammatory cells, although unconfirmed by histology. Conclusion: This provides the first measurement of cochlear vascular permeability using MRI and a quantitative evaluation of the development of cochlear inflammation. MRI holds considerable potential for the assessment of disease processes such as clinical diagnosis of conditions such as labyrinthitis. PMID:23589173

  7. Wilson's disease: MRI features.

    PubMed

    Singh, Paramdeep; Ahluwalia, Archana; Saggar, Kavita; Grewal, Charanpreet Singh

    2011-01-01

    A 15-year-old boy presented with coarse tremors of right hand and dysarthric speech. Neurologic examination demonstrated Kayser-Fleischer rings and dystonic tremor of the right hand. Serum ceruloplasmin and urine copper studies established the diagnosis of Wilson's disease. Brain MRI showed bilateral T2 hyperintensity involving putamen, thalami, and brainstem. Involvement of brainstem revealed the characteristic "double panda sign." PMID:21977083

  8. Wilson's disease: MRI features

    PubMed Central

    Singh, Paramdeep; Ahluwalia, Archana; Saggar, Kavita; Grewal, Charanpreet Singh

    2011-01-01

    A 15-year-old boy presented with coarse tremors of right hand and dysarthric speech. Neurologic examination demonstrated Kayser-Fleischer rings and dystonic tremor of the right hand. Serum ceruloplasmin and urine copper studies established the diagnosis of Wilson's disease. Brain MRI showed bilateral T2 hyperintensity involving putamen, thalami, and brainstem. Involvement of brainstem revealed the characteristic double panda sign. PMID:21977083

  9. MRI Anatomy of Schizophrenia

    PubMed Central

    McCarley, Robert W.; Wible, Cynthia G.; Frumin, Melissa; Hirayasu, Yoshio; Levitt, James J.; Fischer, Iris A.; Shenton, Martha E.

    2010-01-01

    Structural magnetic resonance imaging (MRI) data have provided much evidence in support of our current view that schizophrenia is a brain disorder with altered brain structure, and consequently involving more than a simple disturbance in neurotransmission. This review surveys 118 peerreviewed studies with control group from 1987 to May 1998. Most studies (81%) do not find abnormalities of whole brain/intracranial contents, while lateral ventricle enlargement is reported in 77%, and third ventricle enlargement in 67%. The temporal lobe was the brain parenchymal region with the most consistently documented abnormalities. Volume decreases were found in 62% of 37 studies of whole temporal lobe, and in 81% of 16 studies of the superior temporal gyrus (and in 100% with gray matter separately evaluated). Fully 77% of the 30 studies of the medial temporal lobe reported volume reduction in one or more of its constituent structures (hippocampus, amygdala, parahippocampal gyrus). Despite evidence for frontal lobe functional abnormalities, structural MRI investigations less consistently found abnormalities, with 55% describing volume reduction. It may be that frontal lobe volume changes are small, and near the threshold for MRI detection. The parietal and occipital lobes were much less studied; about half of the studies showed positive findings. Most studies of cortical gray matter (86%) found volume reductions were not diffuse, but more pronounced in certain areas. About two thirds of the studies of subcortical structures of thalamus, corpus callosum and basal ganglia (which tend to increase volume with typical neuroleptics), show positive findings, as do almost all (91%) studies of cavum septi pellucidi (CSP). Most data were consistent with a developmental model, but growing evidence was compatible also with progressive, neurodegenerative features, suggesting a two hit model of schizophrenia, for which a cellular hypothesis is discussed. The relationship of clinical symptoms to MRI findings is reviewed, as is the growing evidence suggesting structural abnormalities differ in affective (bipolar) psychosis and schizophrenia. PMID:10331102

  10. Periodic changes in fMRI connectivity

    PubMed Central

    Handwerker, Daniel A.; Roopchansingh, Vinai; Gonzalez-Castillo, Javier; Bandettini, Peter A.

    2014-01-01

    The first two decades of brain research using fMRI have been dominated by studies that measure signal changes in response to a presented task. A rapidly increasing number of studies are showing that consistent activation maps appear by assessment of signal correlations during time periods in which the subjects were not directed to perform any specific task (i.e. resting state correlations). Even though neural interactions can happen on much shorter time scales, most resting state studies assess these temporal correlations over a period of about 5 to 10 minutes. Here we investigate how these temporal correlations change on a shorter time scale. We examine changes in brain correlations to the posterior cingulate cortex (PCC) across a 10 minutes scan. We show: (1) fMRI correlations fluctuate over time, (2) these fluctuations can be periodic, and (3) correlations between the PCC and other brain regions fluctuate at distinct frequencies. While the precise frequencies of correlation fluctuations vary across subjects and runs, it is still possible to parse brain regions and combinations of brain regions based on fluctuation frequency differences. To evaluate the potential biological significance of these empirical observations, we then use synthetic time series data with identical amplitude spectra, but randomized phase to show that similar effects can still appear even if the timing relationships between voxels are randomized. This implies that observed correlation fluctuations could occur between regions with distinct amplitude spectra, whether or not there are dynamic changes in neural connectivity between such regions. As more studies of brain connectivity dynamics appear, particularly studies using correlation as a key metric, it is vital to better distinguish true neural connectivity dynamics from connectivity fluctuations that are inherently part of this method. Our results also highlight the rich information in the power spectra of fMRI data that can be used to parse brain regions. PMID:22796990

  11. Functional MRI of migraine.

    PubMed

    Schwedt, Todd J; Chiang, Chia-Chun; Chong, Catherine D; Dodick, David W

    2015-01-01

    Migraine is a disabling neurological condition manifesting with attacks of headache, hypersensitivities to visual, auditory, olfactory and somatosensory stimuli, nausea, and vomiting. Exposure to sensory stimuli, such as odours, visual stimuli, and sounds, commonly triggers migraine attacks, and hypersensitivities to sensory stimuli are prominent during migraine attacks, but can persist with less magnitude between attacks. Functional MRI (fMRI) has been used to investigate the mechanisms that lead to migraine sensory hypersensitivities by measuring brain responses to visual, olfactory, and painful cutaneous stimulation, and functional connectivity analyses have investigated the functional organisation of specific brain regions and networks responsible for sensory processing. These studies have consistently shown atypical brain responses to sensory stimuli, absence of the normal habituating response between attacks, and atypical functional connectivity of sensory processing regions. Identification of the mechanisms that lead to migraine sensory hypersensitivities and that trigger migraine attacks in response to sensory stimuli might help to better understand neural dysfunction in migraine and provide new targets for migraine prevention, and could provide fMRI biomarkers that indicate early responses to preventive therapy. PMID:25496899

  12. EEG-assisted retrospective motion correction for fMRI: E-REMCOR.

    PubMed

    Zotev, Vadim; Yuan, Han; Phillips, Raquel; Bodurka, Jerzy

    2012-11-01

    We propose a method for retrospective motion correction of fMRI data in simultaneous EEG-fMRI that employs the EEG array as a sensitive motion detector. EEG motion artifacts are used to generate motion regressors describing rotational head movements with millisecond temporal resolution. These regressors are utilized for slice-specific motion correction of unprocessed fMRI data. Performance of the method is demonstrated by correction of fMRI data from five patients with major depressive disorder, who exhibited head movements by 1-3mm during a resting EEG-fMRI run. The fMRI datasets, corrected using eight to ten EEG-based motion regressors, show significant improvements in temporal SNR (TSNR) of fMRI time series, particularly in the frontal brain regions and near the surface of the brain. The TSNR improvements are as high as 50% for large brain areas in single-subject analysis and as high as 25% when the results are averaged across the subjects. Simultaneous application of the EEG-based motion correction and physiological noise correction by means of RETROICOR leads to average TSNR enhancements as high as 35% for extended brain regions. These TSNR improvements are largely preserved after the subsequent fMRI volume registration and regression of fMRI motion parameters. The proposed EEG-assisted method of retrospective fMRI motion correction (referred to as E-REMCOR) can be applied to improve quality of fMRI data with severe motion artifacts and to reduce spurious correlations between the EEG and fMRI data caused by head movements. It does not require any specialized equipment beyond the standard EEG-fMRI instrumentation and can be applied retrospectively to any existing EEG-fMRI data set. PMID:22836172

  13. Ultrahigh field MRI in clinical neuroimmunology: a potential contribution to improved diagnostics and personalised disease management.

    PubMed

    Sinnecker, Tim; Kuchling, Joseph; Dusek, Petr; Drr, Jan; Niendorf, Thoralf; Paul, Friedemann; Wuerfel, Jens

    2015-01-01

    Conventional magnetic resonance imaging (MRI) at 1.5 Tesla (T) is limited by modest spatial resolution and signal-to-noise ratio (SNR), impeding the identification and classification of inflammatory central nervous system changes in current clinical practice. Gaining from enhanced susceptibility effects and improved SNR, ultrahigh field MRI at 7T depicts inflammatory brain lesions in great detail. This review summarises recent reports on 7T MRI in neuroinflammatory diseases and addresses the question as to whether ultrahigh field MRI may eventually improve clinical decision-making and personalised disease management. PMID:26312125

  14. A brief report on MRI investigation of experimental traumatic brain injury

    PubMed Central

    Duong, Timothy Q.; Watts, Lora T.

    2016-01-01

    Traumatic brain injury is a major cause of death and disability. This is a brief report based on a symposium presentation to the 2014 Chinese Neurotrauma Association Meeting in San Francisco, USA. It covers the work from our laboratory in applying multimodal MRI to study experimental traumatic brain injury in rats with comparisons made to behavioral tests and histology. MRI protocols include structural, perfusion, manganese-enhanced, diffusion-tensor MRI, and MRI of blood-brain barrier integrity and cerebrovascular reactivity. PMID:26981069

  15. Charles L. Brewer Award for Distinguished Teaching of Psychology

    ERIC Educational Resources Information Center

    American Psychologist, 2007

    2007-01-01

    This article announces the 2007 recipient of the Charles L. Brewer Award for Distinguished Teaching of Psychology: Baron Perlman. A brief biography, highlighting areas of special focus in Perlman's work, is provided.

  16. Distinguishability in EIT using a hypothesis-testing model

    NASA Astrophysics Data System (ADS)

    Adler, Andy; Gaggero, Pascal; Maimaitijiang, Yasheng

    2010-04-01

    In this paper we propose a novel formulation for the distinguishability of conductivity targets in electrical impedance tomography (EIT). It is formulated in terms of a classic hypothesis test to make it directly applicable to experimental configurations. We test to distinguish conductivity distributions σ2 from σ1, from which EIT measurements are obtained with added white Gaussian noise with covariance Σn. In order to distinguish the distributions, we must reject the null hypothesis , which has a probability based on the z-score: . This result shows that distinguishability is a product of the impedance change amplitude, the measurement strategy and the inverse of the noise amplitude. This approach is used to explore different current stimulation strategies.

  17. Edna B. Foa: Award for Distinguished Scientific Contributions.

    PubMed

    2015-11-01

    The APA Awards for Distinguished Scientific Contributions are presented to persons who, in the opinion of the Committee on Scientific Awards, have made distinguished theoretical or empirical contributions to basic research in psychology. One of the 2015 award winners is Edna B. Foa, who received this award for "her outstanding and innovative research on the nature, measurement, and treatment of anxiety." Foa's award citation, biography, and a selected bibliography are presented here. (PsycINFO Database Record PMID:26618942

  18. Sodium MRI: Methods and applications

    PubMed Central

    Madelin, Guillaume; Lee, Jae-Seung; Regatte, Ravinder R.; Jerschow, Alexej

    2014-01-01

    Sodium NMR spectroscopy and MRI have become popular in recent years through the increased availability of high-field MRI scanners, advanced scanner hardware and improved methodology. Sodium MRI is being evaluated for stroke and tumor detection, for breast cancer studies, and for the assessment of osteoarthritis and muscle and kidney functions, to name just a few. In this article, we aim to present an up-to-date review of the theoretical background, the methodology, the challenges and limitations, and current and potential new applications of sodium MRI. PMID:24815363

  19. Usefulness of cardiac MRI in the prognosis and follow-up of ischemic heart disease.

    PubMed

    Hidalgo, A; Pons-Llad, G

    2015-01-01

    Cardiac magnetic resonance imaging (MRI) is an important tool that makes it possible to evaluate patients with cardiovascular disease; in addition to infarction and alterations in myocardial perfusion, cardiac MRI is useful for evaluating other phenomena such as microvascular obstruction and ischemia. The main prognostic factors in cardiac MRI are ventricular dysfunction, necrosis in late enhancement sequences, and ischemia in stress sequences. In acute myocardial infarction, cardiac MRI can evaluate the peri-infarct zone and quantify the size of the infarct. Furthermore, cardiac MRI's ability to detect and evaluate microvascular obstruction makes it a fundamental tool for establishing the prognosis of ischemic heart disease. In patients with chronic ischemic heart disease, cardiac MRI can detect ischemia induced by pharmacological stress and can diagnose infarcts that can be missed on other techniques. PMID:25648795

  20. First soluble M@C60 derivatives provide enhanced access to metallofullerenes and permit in vivo evaluation of Gd@C60[C(COOH)2]10 as a MRI contrast agent.

    PubMed

    Bolskar, Robert D; Benedetto, Angelo F; Husebo, Lars O; Price, Roger E; Jackson, Edward F; Wallace, Sidney; Wilson, Lon J; Alford, J Michael

    2003-05-01

    M@C(60) and related endohedral metallofullerenes comprise a significant portion of the metallofullerene yield in the traditional arc synthesis, but their chemistry and potential applications have been largely overlooked because of their sparse solubility. In this work, procedures are described to solublize Gd@C(60) species for the first time by forming the derivative, Gd@C(60)[C(COOCH(2)CH(3))(2)](10), and its hydrolyzed water-soluble form, Gd@C(60)[C(COOH)(2)](10). Imparting water solubility to Gd@C(60) permits its evaluation as a magnetic resonance imaging (MRI) contrast agent. Relaxometry measurements for Gd@C(60)[C(COOH)(2)](10) reveal it to possess a relaxivity (4.6 mM(-1) s(-1) at 20 MHz and 40 degrees C) comparable to that of commercially available Gd(III) chelate-based MRI agents. An in vivo MRI biodistribution study in a rodent model reveals Gd@C(60)[C(COOH)(2)](10) to possess the first non-reticuloendothelial system (RES) localizing