Sample records for enhancement mri distinguishes

  1. Distinguishing intrahepatic cholangiocarcinoma from poorly differentiated hepatocellular carcinoma using precontrast and gadoxetic acid-enhanced MRI

    PubMed Central

    Asayama, Yoshiki; Nishie, Akihiro; Ishigami, Kousei; Ushijima, Yasuhiro; Takayama, Yukihisa; Fujita, Nobuhiro; Kubo, Yuichiro; Aishima, Shinichi; Shirabe, Ken; Yoshiura, Takashi; Honda, Hiroshi

    2015-01-01

    PURPOSE We aimed to gain further insight in magnetic resonance imaging characteristics of mass-forming intrahepatic cholangiocarcinoma (mICC), its enhancement pattern with gadoxetic acid contrast agent, and distinction from poorly differentiated hepatocellular carcinoma (pHCC). METHODS Fourteen mICC and 22 pHCC nodules were included in this study. Two observers recorded the tumor shape, intratumoral hemorrhage, fat on chemical shift imaging, signal intensity at the center of the tumor on T2-weighted image, fibrous capsule, enhancement pattern on arterial phase of dynamic study, late enhancement three minutes after contrast injection (dynamic late phase), contrast uptake on hepatobiliary phase, apparent diffusion coefficient, vascular invasion, and intrahepatic metastasis. RESULTS Late enhancement was more common in mICC (n=10, 71%) than in pHCC (n=3, 14%) (P < 0.001). A fat component was observed in 11 pHCC cases (50%) versus none of mICC cases (P = 0.002). Fibrous capsule was observed in 13 pHCC cases (59%) versus none of mICC cases (P < 0.001). On T2-weighted images a hypointense area was seen at the center of the tumor in 43% of mICC (6/14) and 9% of pHCC (2/22) cases (P = 0.018). Other parameters were not significantly different between the two types of nodules. CONCLUSION The absence of fat and fibrous capsule, and presence of enhancement at three minutes appear to be most characteristic for mICC and may help its differentiation from pHCC. PMID:25698097

  2. 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

  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 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

  5. Can MS lesion stages be distinguished with MRI? A postmortem MRI and histopathology study.

    PubMed

    Jonkman, Laura E; Soriano, Alexandra Lopez; Amor, Sandra; Barkhof, Frederik; van der Valk, Paul; Vrenken, Hugo; Geurts, Jeroen J G

    2015-04-01

    In multiple sclerosis (MS), a histopathological distinction is made between different stages of white matter (WM) lesions. These lesions are characterized as preactive, active, chronic active or chronic inactive, depending on the degree of microglia activation and degree of demyelination. The different lesions are not distinguishable on conventional magnetic resonance imaging (MRI) scans at standard clinical field strengths, but might be distinguished using more advanced, quantitative MRI methods, such as T1 relaxation time (T1-RT) mapping. To investigate this, postmortem brain material from 20 MS patients was investigated, using both T1-RT MRI at 1.5 T and histopathology. The brain material contained a total of 9 preactive, 18 active, 30 chronic active and 14 chronic inactive lesions, as well as 38 areas of normal appearing WM (NAWM). Our results show that, at 1.5 T, T1-RT qMRI can only distinguish between categories NAWM/preactive, active and chronic WM lesions. Advanced imaging at standard field strengths, such as conventional imaging measures, is therefore insufficient to differentiate the WM lesions in MS, and higher field strengths may be required to achieve better pathological differentiation of these lesions. PMID:25761376

  6. 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.

  7. Distinguishing Natural Language Processes on the Basis of fMRI-Measured Brain Activation

    E-print Network

    in sentence processing, the Left Inferior Frontal Gyrus (LIFG), also known as Broca's area, and the LeftDistinguishing Natural Language Processes on the Basis of fMRI-Measured Brain Activation Francisco of the underlying brain activation measured with fMRI. The method uses a classifier to learn to distinguish between

  8. Distinguishing grammatical constructions with fMRI pattern analysis Kachina Allen

    E-print Network

    Botvinick, Matthew

    grammatical patterns. Multi-voxel pattern analysis (MVPA) proved capable of discriminating at aboveDistinguishing grammatical constructions with fMRI pattern analysis Kachina Allen , Francisco and psycholinguistic theories aim to provide psychologically valid analyses of particular grammatical patterns

  9. 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

  10. Body temperature sensitive micelles for MRI enhancement.

    PubMed

    Zhu, Xiaolei; Chen, Shizhen; Luo, Qing; Ye, Chaohui; Liu, Maili; Zhou, Xin

    2015-05-19

    A novel thermo-sensitive micelle contrast agent and its enhancement of MRI contrast with temperature are reported. The morphology changes sharply near 37 °C, resulting in a significant amplification of the CEST signal. This enables detection of small changes in body temperature. PMID:25857517

  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. Manganese enhanced MRI (MEMRI): neurophysiological applications

    PubMed Central

    Inoue, Taeko; Majid, Tabassum; Pautler, Robia G.

    2012-01-01

    Manganese ion (Mn2+) is a calcium (Ca2+) analog that can enter neurons and other excitable cells through voltage gated Ca2+ channels. Mn2+ is also a paramagnetic that shortens the spin-lattice relaxation time constant (T1) of tissues where it has accumulated, resulting in positive contrast enhancement. Mn2+ was first investigated as a magnetic resonance imaging (MRI) contrast agent approximately 20 years ago to assess the toxicity of the metal in rats. In the late 1990s, Alan Koretsky and colleagues pioneered the use of manganese enhanced MRI (MEMRI) towards studying brain activity, tract tracing and enhancing anatomical detail. This review will describe the methodologies and applications of MEMRI in the following areas: monitoring brain activity in animal models, in vivo neuronal tract tracing and using MEMRI to assess in vivo axonal transport rates. PMID:22098448

  13. Distinguishing conjoint and independent neural tuning for stimulus features with fMRI adaptation.

    PubMed

    Drucker, Daniel M; Kerr, Wesley Thomas; Aguirre, Geoffrey Karl

    2009-06-01

    A central focus of cognitive neuroscience is identification of the neural codes that represent stimulus dimensions. One common theme is the study of whether dimensions, such as color and shape, are encoded independently by separate pools of neurons or are represented by neurons conjointly tuned for both properties. We describe an application of functional magnetic resonance imaging (fMRI) adaptation to distinguish between independent and conjoint neural representations of dimensions by examining the neural signal evoked by changes in one versus two stimulus dimensions and considering the metric of two-dimension additivity. We describe how a continuous carry-over paradigm may be used to efficiently estimate this metric. The assumptions of the method are examined as are optimizations. Finally, we demonstrate that the method produces the expected result for fMRI data collected from ventral occipitotemporal cortex while subjects viewed sets of shapes predicted to be represented by conjoint or independent neural tuning. PMID:19357342

  14. POCS-Enhanced Correction of Motion Artifacts in Parallel MRI

    E-print Network

    Utah, University of

    POCS-Enhanced Correction of Motion Artifacts in Parallel MRI Alexey A. Samsonov,1 * Julia Velikina for correction of MRI motion artifacts induced by corrupted k-space data, acquired by multiple receiver coils for recon- struction of sensitivity encoded MRI data (POCSENSE) is employed to identify corrupted k

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

    PubMed

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

    2014-11-28

    Raman spectroscopy has been widely used in biomedical research and clinical diagnostics. It possesses great potentials 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

  16. 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

  17. 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, Gráinne 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

  18. 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 1–5). 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

  19. 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

  20. Focal nodular hyperplasia: characterisation at gadoxetic acid-enhanced MRI and diffusion-weighted MRI

    PubMed Central

    An, H S; Kim, Y J; Jung, S I; Jeon, H J

    2013-01-01

    Purpose: The aim of this study was to assess the enhancement patterns of hepatic focal nodular hyperplasia (FNH) on gadoxetic acid-enhanced MRI and diffusion-weighted (DW) MRI. Methods: This retrospective study had institutional review board approval. Gadoxetic acid-enhanced and DW MR images were evaluated in 23 patients with 30 FNHs (26 histologically proven and 4 radiologically diagnosed). The lesion enhancement patterns of the hepatobiliary phase images were classified as heterogeneous or homogeneous signal intensity (SI), and as dominantly high/iso or low SI compared with those of adjacent liver parenchyma. Heterogeneous (any) SI lesions and homogeneous low SI lesions were categorised into the fibrosis group, whereas homogeneous high/iso SI lesions were categorised into the non-fibrosis group. Additionally, lesion SI on T2 weighted images, DW images and apparent diffusion coefficient (ADC) values were compared between the two groups. Results: The lesions showed heterogeneous high/iso SI (n=16), heterogeneous low SI (n=5), homogeneous high/iso SI (n=7) or homogeneous low SI (n=2) at the hepatobiliary phase MR images. The fibrosis group lesions were more likely to show high SI on DW images and T2 weighted images compared with those in the non-fibrosis group (p<0.05). ADC values tended to be lower in the fibrosis group than those in the non-fibrosis group without significance. Conclusion: FNH showed variable enhancement patterns on hepatobiliary phase images during gadoxetic acid-enhanced MRI. SI on DW and T2 weighted images differed according to the fibrosis component contained in the lesion. Advances in knowledge: FNH shows a wide spectrum of imaging findings on gadoxetic acid-enhanced MRI and DW MRI. PMID:23873903

  1. Angiographic display method for flow-enhanced MRI

    Microsoft Academic Search

    Nola M. Hylton

    1992-01-01

    Magnetic resonance angiography (MRA) is a classification of MRI techniques that produce images of vascular structures. By design, MRA methods enhance contrast between flowing blood and stationary tissue. In bright blood techniques, vascular contrast is maximized using gradient echo sequences with flow compensated magnetic field gradients and short TE values, reduced TR and an imaging slice or slab oriented to

  2. Co-occurrence of local anisotropic gradient orientations (CoLIAGe): distinguishing tumor confounders and molecular subtypes on MRI.

    PubMed

    Prasanna, Prateek; Tiwari, Pallavi; Madabhushi, Anant

    2014-01-01

    We introduce a novel biologically inspired feature descriptor, Co-occurrence of Local Anisotropic Gradient Orientations (CoLlAGe), that captures higher order co-occurrence patterns of local gradient tensors at a pixel level to distinguish disease phenotypes that have similar morphologic appearances. A number of pathologies (e.g. subtypes of breast cancer) have different histologic phenotypes but similar radiographic appearances. While texture features have been previously employed for distinguishing subtly different pathologies, they attempt to capture differences in global intensity patterns. In this paper we attempt to model CoLlAGe to identify higher order co-occurrence patterns of gradient tensors at a pixel level. The assumption behind this new feature is that different pathologies, even though they may have very similar overall texture and appearance on imaging, at a local scale, will have different co-occurring patterns with respect to gradient orientations. We demonstrate the utility of CoLIAGe in distinguishing two subtly different types of pathologies on MRI in the context of brain tumors and breast cancer. In the first problem, we look at CoLlAGe for distinguishing radiation effects from recurrent brain tumors over a cohort of 40 studies, and in the second, discriminating different molecular subtypes of breast cancer over a cohort of 73 studies. For both these challenging cohorts, CoLlAGe was found to have significantly improved classification performance, as compared to the traditional texture features such as Haralick, Gabor, local binary patterns, and histogram of gradients. PMID:25320784

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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, 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.

  4. 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

  5. Gadolinium-enhanced MRI in central nervous system Behçet's disease.

    PubMed

    Erdem, E; Carlier, R; Idir, A B; Masnou, P O; Moulonguet, A; Adams, D; Doyon, D

    1993-01-01

    Two cases of central nervous system Behçet's disease, studied by gadolinium-enhanced MRI, are presented. In one patient, whose clinical picture was dominated by a brain syndrome, the gadolinium enhancement resolved with clinical improvement, although the hyperintense areas in the mesencephalon on T2-weighted images persisted. In the second, who had a pseudobulbar palsy and a mild right hemiparesis, there were many abnormal areas, but an enhancing focus in the posterior limb of the left internal capsule was probably the lesion responsible for the hemiparesis. PMID:8433790

  6. Dynamic oxygen-enhanced MRI of cerebrospinal fluid.

    PubMed

    Mehemed, Taha M; Fushimi, Yasutaka; Okada, Tomohisa; Yamamoto, Akira; Kanagaki, Mitsunori; Kido, Aki; Fujimoto, Koji; Sakashita, Naotaka; Togashi, Kaori

    2014-01-01

    Oxygen causes an increase in the longitudinal relaxation rate of tissues through its T1-shortening effect owing to its paramagnetic properties. Due to such effects, MRI has been used to study oxygen-related signal intensity changes in various body parts including cerebrospinal fluid (CSF) space. Oxygen enhancement of CSF has been mainly studied using MRI sequences with relatively longer time resolution such as FLAIR, and T1 value calculation. In this study, fifteen healthy volunteers were scanned using fast advanced spin echo MRI sequence with and without inversion recovery pulse in order to dynamically track oxygen enhancement of CSF. We also focused on the differences of oxygen enhancement at sulcal and ventricular CSF. Our results revealed that CSF signal after administration of oxygen shows rapid signal increase in both sulcal CSF and ventricular CSF on both sequences, with statistically significant predominant increase in sulcal CSF compared with ventricular CSF. CSF is traditionally thought to mainly form from the choroid plexus in the ventricles and is absorbed at the arachnoid villi, however, it is also believed that cerebral arterioles contribute to the production and absorption of CSF, and controversy remains in terms of the precise mechanism. Our results demonstrated rapid oxygen enhancement in sulcal CSF, which may suggest inhaled oxygen may diffuse into sulcal CSF space rapidly probably due to the abundance of pial arterioles on the brain sulci. PMID:24956198

  7. Sturge-Weber syndrome with no leptomeningeal enhancement on MRI

    Microsoft Academic Search

    N. J. Fischbein; A. J. Barkovich; Y. Wu; B. O. Berg

    1998-01-01

    Sturge-Weber syndrome (SWS) is a neurocutaneous syndrome characterized by a facial nevus flammeus associated with seizures,\\u000a developmental delay, and, often, with hemiparesis and hemianopia. On MRI, the most characteristic finding has been reported\\u000a to be leptomeningeal enhancement, believed to represent leakage of contrast medium through the anomalous pial vessels that\\u000a characterize the disease. We present a case of SWS with

  8. In vivo Overhauser-enhanced MRI of proteolytic activity.

    PubMed

    Koonjoo, Neha; Parzy, Elodie; Massot, Philippe; Lepetit-Coiffé, Matthieu; Marque, Sylvain R A; Franconi, Jean-Michel; Thiaudiere, Eric; Mellet, Philippe

    2014-01-01

    There is an increasing interest in developing novel imaging strategies for sensing proteolytic activities in intact organisms in vivo. Overhauser-enhanced MRI (OMRI) offers the possibility to reveal the proteolysis of nitroxide-labeled macromolecules thanks to a sharp decrease of the rotational correlation time of the nitroxide moiety upon cleavage. In this paper, this concept is illustrated in vivo at 0.2 T using nitroxide-labeled elastin orally administered in mice. In vitro, this elastin derivative was OMRI-visible and gave rise to high Overhauser enhancements (19-fold at 18 mm nitroxide) upon proteolysis by pancreatic porcine elastase. In vivo three-dimensional OMRI detection of proteolysis was carried out. A keyhole fully balanced steady-state free precession sequence was used, which allowed 3D OMRI acquisition within 20 s at 0.125 mm(3) resolution. About 30 min after mouse gavage, proteolysis was detected in the duodenum, where Overhauser enhancements were 7.2 ± 2.4 (n = 7) and was not observed in the stomach. Conversely, orally administered free nitroxides or pre-digested nitroxide-labeled elastin were detected in the mouse's stomach by OMRI. Combined with specific molecular probes, this Overhauser-enhanced MRI technique can be used to evaluate unregulated proteolytic activities in various models of experimental diseases and for drug testing. PMID:24729587

  9. Gadolinium-DOTA enhanced MRI of painful osseous crises in children with sickle cell anemia

    Microsoft Academic Search

    V. Bonnerot; G. Sebag; M. de Montalembert; M. Wioland; C. Glorion; R. Girot; D. Lallemand

    1994-01-01

    In order to evaluate the role of gadolinium-DOTA enhanced MRI in the management of painful osseous crises in children with sickle cell anemia (SCA), nine children with SCA underwent MRI, bone scans and ultrasonographic studies during 11 osseous crises. Imaging findings were compared with the final diagnosis: three acute osteomyelitis (AO) and 16 acute infarcts (AI). MRI could not differentiate

  10. Subdural enhancement on postoperative spinal MRI after resection of posterior cranial fossa tumours

    Microsoft Academic Search

    M. Warmuth-Metz; J. Krauss; L. Solymosi

    2004-01-01

    In malignant brain tumours which may disseminate staging, usually by cranial and spinal MRI is necessary. If MRI is performed in the postoperative period pitfalls should be considered. Nonspecific subdural contrast enhancement on spinal staging MRI is rarely reported after resection of posterior fossa tumours, which may be mistaken for dissemination of malignancy. We investigated the frequency of spinal subdural

  11. IMPATIENT MRI: ILLINOIS MASSIVELY PARALLEL ACCELERATION TOOLKIT FOR IMAGE RECONSTRUCTION WITH ENHANCED

    E-print Network

    Hwu, Wen-mei W.

    IMPATIENT MRI: ILLINOIS MASSIVELY PARALLEL ACCELERATION TOOLKIT FOR IMAGE RECONSTRUCTION WITH ENHANCED THROUGHPUT IN MRI Xiao-Long Wu1 , Jiading Gai2 , Fan Lam1,2 , Maojing Fu1,2 , Justin P. Haldar1 and temporal resolution in magnetic resonance imaging (MRI). Additionally, significant developments in image

  12. A Simulation Tool for Dynamic Contrast Enhanced MRI

    PubMed Central

    Mauconduit, Franck; Christen, Thomas; Barbier, Emmanuel Luc

    2013-01-01

    The quantification of bolus-tracking MRI techniques remains challenging. The acquisition usually relies on one contrast and the analysis on a simplified model of the various phenomena that arise within a voxel, leading to inaccurate perfusion estimates. To evaluate how simplifications in the interstitial model impact perfusion estimates, we propose a numerical tool to simulate the MR signal provided by a dynamic contrast enhanced (DCE) MRI experiment. Our model encompasses the intrinsic and relaxations, the magnetic field perturbations induced by susceptibility interfaces (vessels and cells), the diffusion of the water protons, the blood flow, the permeability of the vessel wall to the the contrast agent (CA) and the constrained diffusion of the CA within the voxel. The blood compartment is modeled as a uniform compartment. The different blocks of the simulation are validated and compared to classical models. The impact of the CA diffusivity on the permeability and blood volume estimates is evaluated. Simulations demonstrate that the CA diffusivity slightly impacts the permeability estimates ( for classical blood flow and CA diffusion). The effect of long echo times is investigated. Simulations show that DCE-MRI performed with an echo time may already lead to significant underestimation of the blood volume (up to 30% lower for brain tumor permeability values). The potential and the versatility of the proposed implementation are evaluated by running the simulation with realistic vascular geometry obtained from two photons microscopy and with impermeable cells in the extravascular environment. In conclusion, the proposed simulation tool describes DCE-MRI experiments and may be used to evaluate and optimize acquisition and processing strategies. PMID:23516414

  13. 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

  14. 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 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

  15. Diagnosis of suspicious breast lesions using an empirical mathematical model for dynamic contrast-enhanced MRI

    PubMed Central

    Fan, Xiaobing; Medved, Milica; Karczmar, Gregory S.; Yang, Cheng; Foxley, Sean; Arkani, Sanaz; Recant, Wendy; Zamora, Marta A.; Abe, Hiroyuki; Newstead, Gillian M.

    2010-01-01

    The purpose of this study was to test whether an empirical mathematical model (EMM) of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can distinguish between benign and malignant breast lesions. A modified clinical protocol was used to improve the sampling of contrast medium uptake and washout. T1-weighted DCE magnetic resonance images were acquired at 1.5 T for 22 patients before and after injection of Gd-DTPA. Contrast medium concentration as a function of time was calculated over a small region of interest containing the most rapidly enhancing pixels. Then the curves were fitted with the EMM, which accurately described contrast agent uptake and washout. Results demonstrate that benign lesions had uptake (P < 2.0 × 10?5) and washout (P <.01) rates of contrast agent significantly slower than those of malignant lesions. In addition, secondary diagnostic parameters, such as time to peak of enhancement, enhancement slope at the peak and curvature at the peak of enhancement, were derived mathematically from the EMM and expressed in terms of primary parameters. These diagnostic parameters also effectively differentiated benign from malignant lesions (P <.03). Conventional analysis of contrast medium dynamics, using a subjective classification of contrast medium kinetics in lesions as ‘washout,’ ‘plateau’ or ‘persistent’ (sensitivity=83%, specificity=50% and diagnostic accuracy=72%), was less effective than the EMM (sensitivity=100%, specificity=83% and diagnostic accuracy=94%) for the separation of benign and malignant lesions. In summary, the present research suggests that the EMM is a promising alternative method for evaluating DCE-MRI data with improved diagnostic accuracy. PMID:17540270

  16. 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

  17. 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 [Tottori Univ. School of Medicine, Yonago (Japan)] [Tottori Univ. School of Medicine, Yonago (Japan)

    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

  18. A new denoising method for dynamic contrast-enhanced MRI.

    PubMed

    Gal, Yaniv; Mehnert, Andrew; Bradley, Andrew; McMahon, Kerry; Kennedy, Dominic; Crozier, Stuart

    2008-01-01

    This paper presents a new algorithm for denoising dynamic contrast-enhanced (DCE) MR images. The algorithm is called Dynamic Non-Local Means and is a novel variation on the Non-Local Means (NL-Means) algorithm. It exploits the redundancy of information in the DCE-MRI sequence of images. An evaluation of the performance of the algorithm relative to six other denoising algorithms-Gaussian filtering, the original NL-Means algorithm, bilateral filtering, anisotropic diffusion filtering, the wavelets adaptive multiscale products threshold method, and the traditional wavelet thresholding method-is also presented. The evaluation was performed by two groups of expert observers-18 signal/image processing experts, and 9 clinicians (8 radiographers and 1 radiologist)-using real DCE-MRI data. The results of the evaluation provide evidence, at the alpha=0.05 level of significance, that both groups of observers deem the DNLM algorithm to perform visually better than all of the other algorithms. PMID:19162789

  19. Contrast-enhanced MRI-guided photodynamic cancer therapy with a pegylated bifunctional polymer conjugate

    PubMed Central

    Vaidya, Anagha; Sun, Yongen; Feng, Yi; Emerson, Lyska; Jeong, Eun-Kee; Lu, Zheng-Rong

    2008-01-01

    Purpose To study contrast-enhanced MRI guided photodynamic therapy with a pegylated bifunctional polymer conjugate containing an MRI contrast agent and a photosensitizer for minimally invasive image-guided cancer treatment. Methods Pegylated and non-pegylated poly-(L-glutamic acid) conjugates containing mesochlorin e6, a photosensitizer, and Gd(III)-DO3A, an MRI contrast agent, were synthesized. The effect of pegylation on the biodistribution and tumor targeting was non-invasively visualized in mice bearing MDA-MB-231 tumor xenografts with MRI. MRI-guided photodynamic therapy was carried out in the tumor bearing mice. Tumor response to photodynamic therapy was evaluated by dynamic contrast enhanced MRI and histological analysis. Results The pegylated conjugate had longer blood circulation, lower liver uptake and higher tumor accumulation than the non-pegylated conjugate as shown by MRI. Site-directed laser irradiation of tumors resulted in higher therapeutic efficacy for the pegylated conjugate than the non-pegylated conjugate. Moreover, animals treated with photodynamic therapy showed reduced vascular permeability on DCE-MRI and decreased microvessel density in histological analysis. Conclusions Pegylation of the polymer bifunctional conjugates reduced non-specific liver uptake and increased tumor uptake, resulting in significant tumor contrast enhancement and high therapeutic efficacy. The pegylated poly(L-glutamic acid) bifunctional conjugate is promising for contrast enhanced MRI guided photodynamic therapy in cancer treatment. PMID:18584312

  20. Multiparametric imaging of tumor oxygenation, redox status, and anatomical structure using Overhauser-enhanced MRI-prepolarized MRI system.

    PubMed

    Ahn, Kang-Hyun; Scott, Greig; Stang, Pascal; Conolly, Steve; Hristov, Dimitre

    2011-05-01

    An integrated Overhauser-enhanced MRI-Prepolarized MRI system was developed to obtain radiobiological information that could be accurately coregistered with diagnostic quality anatomic images. EPR and NMR images were acquired through the double resonance technique and field cycling of the main magnetic field from 5 mT to 0.5 T. Dedicated EPR and NMR coils were devised to minimize radiofrequency power deposition with high signal-to-noise ratio. Trityl and nitroxide radicals were used to characterize oxygen and redox sensitivities of multispin echo Overhauser-enhanced MRI. Oxygen resolution of 3 mmHg was obtained from 2 mM deoxygenated trityl phantoms. Trityl radicals were stable in reducing environments and did not alter the redox-sensitive decaying rate of the nitroxide signals. Nitroxide radicals had a compounding effect for the trityl oximetry. Tumor oxygenation and redox status were acquired with anatomical images by injecting trityl and nitroxide probes subsequently in murine tumors. The Overhauser-enhanced MRI-Prepolarized MRI system is ready for quantitative longitudinal imaging studies of tumor hypoxia and redox status as radiotherapy prognostic factors. PMID:21500268

  1. Immunological Time-Course of Gadolinium-Enhancing MRI Lesions in Patients with Multiple Sclerosis

    Microsoft Academic Search

    G. Giovannoni; N. C. Silver; C. D. Good; D. H. Miller; E. J. Thompson

    2000-01-01

    In multiple sclerosis (MS) gadolinium (Gd)-enhanced MRI activity correlates weakly with immunological markers of disease activity. We, therefore, tested the hypothesis that the poor correlation could be partly explained by the temporal profile of Gd enhancement. We measured urinary neopterin:creatinine ratios (neopt.:creat.urine) in 5 patients with active MS undergoing weekly Gd-enhanced MRI studies of the brain. The neopt.:creat.urine associated with

  2. 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

  3. Diagnosis of cirrhosis with intravoxel incoherent motion diffusion MRI and dynamic contrast-enhanced MRI alone and in combination: preliminary experience

    Microsoft Academic Search

    Jignesh Patel; Eric E. Sigmund; Henry Rusinek; Marcel Oei; James S. Babb; Bachir Taouli

    2010-01-01

    PURPOSE: To report our preliminary experience with the use of intravoxel incoherent motion (IVIM) diffusion-weighted magnetic resonance imaging (DW-MRI) and dynamic contrast-enhanced (DCE)-MRI alone and in combination for the diagnosis of liver cirrhosis. MATERIALS AND METHODS: Thirty subjects (16 with noncirrhotic liver, 14 with cirrhosis) were prospectively assessed with IVIM DW-MRI (n = 27) and DCE-MRI (n = 20). IVIM

  4. Segmentation of Pathologic Hearts in Long-Axis Late-Enhancement MRI

    E-print Network

    Paris-Sud XI, Université de

    Segmentation of Pathologic Hearts in Long-Axis Late-Enhancement MRI Cyb`ele Ciofolo and Maxim. We propose a new method to segment long-axis cardiac MR images acquired with a late-enhancement appears dark while the intensity of enhanced areas ranges from gray to white, depending on the myocardial

  5. Improving Bladder Cancer Imaging Using 3T Functional Dynamic Contrast-Enhanced MRI

    PubMed Central

    Nguyen, Huyen T.; Pohar, Kamal S.; Jia, Guang; Shah, Zarine K.; Mortazavi, Amir; Zynger, Debra L.; Wei, Lai; Clark, Daniel; Yang, Xiangyu; Knopp, Michael V.

    2015-01-01

    Objectives To assess the capability of T2-weighted MRI (T2W-MRI) and the additional diagnostic value of Dynamic Contrast-Enhanced MRI (DCE-MRI) using multi-transmit 3T in the localization of bladder cancer. Materials and Methods This prospective study was approved by the local Institutional Review Board. Thirty–six patients were included in the study and provided informed consent. MRI scans were performed with T2W-MRI and DCE-MRI on a 3T multi-transmit system. Two observers (with 12 and 25 years of experience) independently interpreted T2W-MRI prior to DCE-MRI data (maps of pharmacokinetic parameters) to localize bladder tumors. The pathological examination of cystectomy bladder specimens was used as a reference gold standard. The McNemar test was performed to evaluate the differences in sensitivity, specificity, and accuracy. Kappa scores were calculated to assess interobserver agreement. Results The sensitivity, specificity, and accuracy of the localization with T2W-MRI alone were 81% (29/36), 63% (5/8) and 77% (34/44) for observer 1, and 72% (26/36), 63% (5/8), and 70% (31/44) for observer 2. With additional DCE-MRI available, these values were 92% (33/36), 75% (6/8), and 89% (39/44) for observer 1, and 92% (33/36), 63% (5/8), and 86% (38/44) for observer 2. DCE-MRI significantly (P < 0.01) improved the sensitivity and accuracy for observer 2. For the twenty-three patients treated with chemotherapy, DCE-MRI also significantly (P < 0.02) improved the sensitivity and accuracy of bladder cancer localization with T2W-MRI alone for observer 2. Kappa scores were 0.63 for T2W-MRI alone, and 0.78 for additional DCE-MRI. Out of seven sub-centimeter malignant tumors, four (57%) were identified on T2W images and six (86%) on DCE maps. Out of eleven malignant tumors within the bladder wall thickening, six (55%) were found on T2W images and ten (91%) on DCE maps. Conclusions Compared to conventional T2W-MRI alone, the addition of DCE-MRI improved interobserver agreement as well as the localization of small malignant tumors and those within bladder wall thickening. PMID:24637583

  6. VEGFR2-Targeted Contrast-Enhanced Ultrasound to Distinguish between Two Anti-Angiogenic Treatments.

    PubMed

    Payen, Thomas; Dizeux, Alexandre; Baldini, Capucine; Le Guillou-Buffello, Delphine; Lamuraglia, Michele; Comperat, Eva; Lucidarme, Olivier; Bridal, S Lori

    2015-08-01

    The aim of this study was to evaluate the capacity of BR55, an ultrasound contrast agent specifically targeting vascular endothelial growth factor receptor 2 (VEGFR2), to distinguish the specific anti-VEGFR2 therapy effect of sunitinib from other anti-angiogenic effects of a therapy (imatinib) that does not directly inhibit VEGFR2. Sunitinib, imatinib and placebo were administered daily for 11 d (264 h) to 45 BalbC mice bearing ectopic CT26 murine colorectal carcinomas. During the course of therapy, B-mode ultrasound, contrast-enhanced ultrasound and VEGFR2-targeted contrast-enhanced ultrasound were performed to assess tumor morphology, vascularization and VEGFR2 expression, respectively. The angiogenic effects on these three aspects were characterized using tumor volume, contrast-enhanced area and differential targeted enhancement. Necrosis, microvasculature and expression of VEGFR2 were also determined by histology and immunostaining. B-Mode imaging revealed that tumor growth was significantly decreased in sunitinib-treated mice at day 11 (p < 0.05), whereas imatinib did not affect growth. Functional evaluation revealed that the contrast-enhanced area decreased significantly (p < 0.02) and by similar amounts under both anti-angiogenic treatments by day 8 (192 h): -23% for imatinib and -21% for sunitinib. No significant decrease was observed in the placebo group. Targeted contrast-enhanced imaging revealed lower differential targeted enhancement, that is, lower levels of VEGFR2 expression, in sunitinib-treated mice relative to placebo-treated mice from 24 h (p < 0.05) and relative to both placebo- and imatinib-treated mice from 48 h (p < 0.05). Histologic assessment of tumors after the final imaging indicated that necrotic area was significantly higher for the sunitinib group (21%) than for the placebo (8%, p < 0.001) and imatinib (11%, p < 0.05) groups. VEGFR2-targeted ultrasound was able to sensitively differentiate the anti-VEGFR2 effect from the reduced area of tumor with functional flow produced by both anti-angiogenic agents. BR55 molecular imaging was, thus, able both to detect early therapeutic response to sunitinib in CT26 tumors as soon as 24 h after the beginning of the treatment and to provide early discrimination (48 h) between tumor response during anti-angiogenic therapy targeting VEGFR2 expression and response during anti-angiogenic therapy not directly acting on this receptor. PMID:25980323

  7. 2008 Fall : Distinguished Honors Distinguished

    E-print Network

    Kasman, Alex

    Baust Amanda L Distinguished Beard John Elliot Distinguished Beckwith Brantley Wallace Distinguished Distinguished Boggs Kyle Todd Distinguished Bonanno Alicia Marie Distinguished Bongalis Alixandra Rebaka

  8. In vivo Visuotopic Brain Mapping with Manganese-Enhanced MRI and Resting-State Functional Connectivity MRI

    PubMed Central

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

    2014-01-01

    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 Mn2+ 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 Mn2+ 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 Mn2+ transfer but not intra- or inter-hemispheric monosynaptic Mn2+ transport after Mn2+ 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

  9. The emerging role of ferumoxytol-enhanced MRI in the management of cerebrovascular lesions.

    PubMed

    Chalouhi, Nohra; Jabbour, Pascal; Magnotta, Vincent; Hasan, David

    2013-01-01

    Inflammation is increasingly being understood to be a key component to the pathophysiology of cerebrovascular lesions. Ferumoxytol, an iron oxide nanoparticle coated by a carbohydrate shell, has been used in MRI studies as an inflammatory marker because it is cleared by macrophages. Ferumoxytol-enhanced MRI has emerged as an important tool for noninvasive assessment of the inflammatory status of cerebrovascular lesions, namely aneurysms and arteriovenous malformations. Moreover, preliminary evidence suggests that ferumoxytol-enhanced MRI could be applied as a non-invasive tool to differentiate "unstable" lesions that require early intervention from "stable" lesions in which observation may be safe. Assessment of the effects of anti-inflammatory pharmacological interventions on cerebrovascular lesions is also a potentially crucial application of the technique. Future improvements in technique and MRI signal quantification will certainly pave the way for widespread and efficient use of ferumoxytol-enhanced MRI in clinical practice. In this paper, we review current data regarding ferumoxytol-enhanced MRI and discuss its current/potential applications and future perspectives. PMID:23945642

  10. The clinical significance of gadolinium enhancement of lumbar disc herniations and nerve roots on preoperative MRI

    Microsoft Academic Search

    P. C. A. J. Vroomen; S. J. M. Van Hapert; R. E. H. Van Acker; E. A. M. Beuls; A. G. H. Kessels; J. T. Wilmink

    1998-01-01

    The clinical significance of preoperative gadolinium DPTA enhancement around disc herniations and in the epidural space on\\u000a MRI is not clear. The relation of nerve root enhancement to dysfunction also remains controversial. To investigate the clinical\\u000a significance of contrast enhancement we looked at the symptoms and signs and gadolinium DPTA-enhanced images of 71 consecutive\\u000a surgical candidates in a standardised fashion.

  11. 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…

  12. Contrast-Enhanced MRI-Guided Photodynamic Cancer Therapy with a Pegylated Bifunctional Polymer Conjugate

    Microsoft Academic Search

    Anagha Vaidya; Yongen Sun; Yi Feng; Lyska Emerson; Eun-Kee Jeong; Zheng-Rong Lu

    2008-01-01

    Purpose  To study contrast-enhanced MRI guided photodynamic therapy with a pegylated bifunctional polymer conjugate containing an MRI\\u000a contrast agent and a photosensitizer for minimally invasive image-guided cancer treatment.\\u000a \\u000a \\u000a \\u000a Methods  Pegylated and non-pegylated poly-(l-glutamic acid) conjugates containing mesochlorin e6, a photosensitizer, and Gd(III)-DO3A, an MRI contrast agent, were synthesized. The effect of pegylation on the biodistribution\\u000a and tumor targeting was non-invasively visualized in

  13. Dynamic contrast enhanced MRI in patients with diabetic macular edema: initial results

    Microsoft Academic Search

    Gary L. Trick; Jessica Liggett; Jamie Levy; Ingrid Adamsons; Paul Edwards; Uday Desai; Paul S. Tofts; Bruce A. Berkowitz

    2005-01-01

    To assess the ability of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) to detect blood retinal barrier (BRB) damage in patients with diabetic macular edema (DME).DCE-MRI with 0.1mmol Gd-DTPA was used to measure BRB permeability in 10 healthy and visually normal subjects and eight patients with DME, including five patients with non-clinically significant (NCS) DME and three patients with clinically

  14. Asymptomatic renal abscess: Evaluation with gadolinium DTPA-enhanced MRI

    Microsoft Academic Search

    K. M. Cyran; P. J. Kenney

    1994-01-01

    Incidental detection of renal mass in a transplant patient is a diagnostic challenge. These patients are at risk for the development of neoplasms and, more commonly, infection with atypical organisms. Symptomatology may be lacking in either, and both conditions may present with similar symptoms. Magnetic resonance imaging (MRI) evaluation with gadolinium DTPA is helpful in the evaluation of asymptomatic renal

  15. Late adverse events after enhanced and unenhanced MRI and CT: a prospective study.

    PubMed

    Azzouz, Manal; Rømsing, Janne; Thomsen, Henrik S

    2014-05-01

    Prospective evaluation of frequency of late and very late adverse events in patients undergoing enhanced or unenhanced magnetic resonance imaging (MRI) or computed tomography (CT). The imaging procedure was performed according to the protocols of the department. All patients were contacted 3 days after their imaging procedure for the occurrence of late adverse events (LAEs) and a month later for the occurrence of very late adverse events (VLAEs) using a structured questionnaire. A total of 1042 (71%) among 1473 patients completed both the 3-day and 1-month questionnaire. The incidence of LAEs was significantly higher in the enhanced MRI (38%) and CT (27%) groups than unenhanced MRI (20%) and CT (16%) groups. The frequency of nausea, dizziness, abdominal pain and diarrhoea was significantly higher in the enhanced MRI group than in the MRI control group, while taste sensation was reported more frequent in the enhanced CT group than in the CT control group. The incidence of VLAEs was significantly higher in the enhanced CT (21%) than unenhanced CT group (13%). The same LAEs and VLAEs were reported in all four groups. LAEs and VLAEs were reported more often in patients with allergy in both the enhanced and unenhanced groups. The incidence of LAEs and VLAEs was higher in the enhanced groups than in the unenhanced groups. The most reported adverse events in the enhanced groups were also reported in the unenhanced groups. Patients with allergy reported LAE and VLAE more often. This suggests that adverse events may not always be caused by the contrast media. PMID:24238213

  16. 78 FR 12329 - Distinguishing Medical Device Recalls From Product Enhancements; Reporting Requirements; Draft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-22

    ...Distinguishing Medical Device Recalls From...Center for Devices and Radiological...of Dockets Management (HFA-305...Center for Devices and Radiological...of marketed medical devices can...an effective quality system, often...

  17. Preparation of Magnetite Nanoemulsion Stabilized by Tween 81 for MRI Contrast Enhancement

    NASA Astrophysics Data System (ADS)

    Nikolaev, Boris P.; Eliseev, Oleg V.; Marchenko, Yaroslav Yu.; Yakovleva, Liudmila Yu.; Zimina, Tatiana M.; Soloviev, Alexei V.; Luchinin, Victor V.

    2010-12-01

    Magnetite nanoemulsions (NE) were synthesized via procedure of heterophase synthesis in a ternary system: Tween 81/pentadecane/water. Prepared NEs were studied by dynamic light scattering and NMR spectroscopy. Their size was of the order of 10 nm and they revealed superparamagnetic properties. MRI efficiency of the NEs was demonstrated by measuring magnetic spin-spin relaxation rates, which complied with the properties of negative contrast agents. MRI of agar phantom demonstrates high grade of contrast enhancement in vitro. Toxicity of the preparations was studied on murine model. Studies revealed no signs of acute or short-term (within 30 days) toxicity in mice. Synthesized magnetite NEs have potential for in vivo MRI contrast enhancement applications.

  18. USPIO-Enhanced Dynamic MRI: Evaluation of Normal and Transplanted Rat Kidneys

    E-print Network

    Moura, José

    USPIO-Enhanced Dynamic MRI: Evaluation of Normal and Transplanted Rat Kidneys Dewen Yang,1 Qing Ye, 40 normal rats (20 Dark Agouti (DA) rats and 20 Brown Norway (BN) rats) and 16 transplanted rats (12) coronal dynamic studies in 43 s. In the normal rats, a larger maximum signal decrease (MSD) in the cortex

  19. Delayed Contrast Enhancement and Perfusable Tissue Index in Hypertrophic Cardiomyopathy: Comparison Between Cardiac MRI and PET

    Microsoft Academic Search

    Paul Knaapen; Willem G. van Dockum; Olga Bondarenko; Wouter E. M. Kok; Marco J. W. Gotte; Ronald Boellaard; Aernout M. Beek; Cees A. Visser; Albert C. van Rossum; Adriaan A. Lammertsma; Frans C. Visser

    Delayed contrast enhancement (DCE) visualized by cardiac MRI (CMR) is a common feature in patients with hypertrophic car- diomyopathy (HCM), presumed to be related to myocardial fibrosis. The pathophysiologic basis of hyperenhancement in this patient group, however, remains unclear as limited histo- logic comparisons are available. The present study compares the perfusable tissue index (PTI), an alternative marker of myo-

  20. An Integrated Method of Adaptive Enhancement for Unsupervised Segmentation of MRI Brain Images

    E-print Network

    Pizurica, Aleksandra

    ) and an unsupervised local classification algorithm (Fuzzy C-Means clus- tering) are used for segmentation. In orderAn Integrated Method of Adaptive Enhancement for Unsupervised Segmentation of MRI Brain Images versatile wavelet-based filter, and segment the images with minimum error global thresholding. Subsequently

  1. High Speed 3D Overhauser-Enhanced MRI Using Combined b-SSFP and Compressed Sensing

    E-print Network

    Rosen, Matthew S

    radicals in living organisms, and for the study of dynamic processes such as metabolism and flow. Magn: Overhauser-enhanced MRI is a promising technique for imaging the distribution and dynamics of free radicals to saturate the electron resonance. Methods: The approach presented here embeds EPR pulses within a balanced

  2. Randomized multicentre trial of gadoxetic acid-enhanced MRI versus conventional MRI or CT in the staging of colorectal cancer liver metastases

    PubMed Central

    Zech, C J; Korpraphong, P; Huppertz, A; Denecke, T; Kim, M-J; Tanomkiat, W; Jonas, E; Ba-Ssalamah, A

    2014-01-01

    Background This multicentre international randomized trial compared the impact of gadoxetic acid-enhanced magnetic resonance imaging (MRI), MRI with extracellular contrast medium (ECCM-MRI) and contrast-enhanced computed tomography (CE-CT) as a first-line imaging method in patients with suspected colorectal cancer liver metastases (CRCLM). Methods Between October 2008 and September 2010, patients with suspected CRCLM were randomized to one of the three imaging modalities. The primary endpoint was the proportion of patients for whom further imaging after initial imaging was required for a confident diagnosis. Secondary variables included confidence in the therapeutic decision, intraoperative deviations from the initial imaging-based surgical plan as a result of additional operative findings, and diagnostic efficacy of the imaging modalities versus intraoperative and pathological extent of the disease. Results A total of 360 patients were enrolled. Efficacy was analysed in 342 patients (118, 112 and 112 with gadoxetic acid-enhanced MRI, ECCM-MRI and CE-CT respectively as the initial imaging procedure). Further imaging was required in 0 of 118, 19 (17·0 per cent) of 112 and 44 (39·3 per cent) of 112 patients respectively (P < 0·001). Diagnostic confidence was high or very high in 98·3 per cent of patients for gadoxetic acid-enhanced MRI, 85·7 per cent for ECCM-MRI and 65·2 per cent for CE-CT. Surgical plans were changed during surgery in 28, 32 and 47 per cent of patients in the respective groups. Conclusion The diagnostic performance of gadoxetic acid-enhanced MRI was better than that of CE-CT and ECCM-MRI as the initial imaging modality. No further imaging was needed in the gadoxetic acid-enhanced MRI group and comparison of diagnostic efficacy parameters demonstrated the diagnostic superiority of gadoxetic acid-enhanced MRI. Registration number: NCT00764621( http://clinicaltrials.gov ); EudraCT number: 2008-000583-16 ( https://eudract.ema.europa.eu/ ). PMID:24652690

  3. MRI

    NSDL National Science Digital Library

    Patient Education Institute

    This patient education program explains Magnetic Resonance Imaging (MRI), the role of this imaging in diagnosis, the procedure itself, and associated benefits and risks. This is a MedlinePlus Interactive Health Tutorial from the National Library of Medicine, designed and developed by the Patient Education Institute. NOTE: The tutorial requires a special Flash plug-in, version 4 or above. If you do not have Flash, you will be prompted to obtain a free download of the software before you start the tutorial. You will also need an Acrobat Reader, available as a free download, in order to view the Reference Summary.

  4. Model Selection in Measures of Vascular Parameters using Dynamic Contrast Enhanced MRI: Experimental and Clinical Applications

    PubMed Central

    Ewing, James R.; Bagher-Ebadian, Hassan

    2013-01-01

    A review of the selection of models in dynamic contrast enhanced MRI (DCE-MRI) is conducted, with emphasis on the balance between bias and variance required to produce stable and accurate estimates of vascular parameters. The vascular parameters considered as a first-order model are the forward volume transfer constant, Ktrans, plasma volume fraction, vp, and the interstitial volume fraction, ve. To illustrate the critical issues in model selection, a data-driven selection of models in an animal model of cerebral glioma is followed. Systematic errors and extended models are considered. Studies with nested and non-nested pharmacokinetic models are reviewed; models considering water exchange are considered. PMID:23881857

  5. USPIO-enhanced MRI for preoperative staging of gynecological pelvic tumors: preliminary results.

    PubMed

    Keller, Thomas M; Michel, Sven C A; Fröhlich, Johannes; Fink, Daniel; Caduff, Rosmarie; Marincek, Borut; Kubik-Huch, Rahel A

    2004-06-01

    The aim of this study was to assess nodal enhancement with ultrasmall superparamagnetic iron oxide (USPIO)-enhanced magnetic resonance imaging (MRI) during preoperative staging of gynecological pelvic tumors within the same imaging session for the primary tumor. Pelvic MRI was performed 18-28 h after intravenous infusion of USPIO (Combidex/Sinerem, 2.6 mg Fe/kg body weight) in 13 women (mean age 51 years) scheduled for surgery for biopsy proven ( n=11) or clinically suspected ( n=2) uterine carcinoma. Axial T1-weighted spin-echo (SE), T2-weighted fast SE (FSE; with fat saturation), fast spoiled gradient-recalled (FSPGR) echo, sagittal and oblique T2-weighted FSE sequences were acquired on a 1.5-T system. Lymph nodes were prospectively staged using standard criteria, i.e., size and shape, as well as USPIO enhancement. Results were correlated with histology findings. MRI correctly staged all primary uterine tumors. In one case, the preoperative diagnosis of stage IV switched the therapeutic approach to radiochemotherapy. Ninety-one (86 benign, 5 malignant) of the histologically characterized nodes could be correlated with their MRI counterparts. One node was false positive; three micrometastases greater than 5 mm and one 5-mm metastasis were missed. On a nodal basis, the sensitivity score was 0.33 and the specificity score, 0.99. On a patient basis, the sensitivity score was 0.25 and the specificity score, 0.80. Our preliminary results indicate that USPIO-enhanced pelvic MRI for preoperative nodal assessment is feasible within one imaging session for primary tumors and that it has a high specificity. However, the low sensitivity in the present study is a limitation for the clinical application of this technique. PMID:14991323

  6. Rapidly enhancing hepatic hemangiomas at MRI: distinction from malignancies with T2-weighted images.

    PubMed

    Outwater, E K; Ito, K; Siegelman, E; Martin, C E; Bhatia, M; Mitchell, D G

    1997-01-01

    The purpose of this study is to describe a subset of atypical hepatic hemangiomas that enhance rapidly and diffusely and to determine whether heavily T2-weighted images could distinguish between atypically enhancing liver hemangiomas and hypervascular malignancies. A retrospective search of MR records identified seven patients with liver hemangiomas that demonstrated diffuse early enhancement and 23 patients with biopsy-proven malignant liver lesions that were hypervascular on dynamic gadolinium-enhanced MR images. Quantitative analysis of signal intensity measurements was performed on the T2-weighted images, heavily T2-weighted (TE > 140), and dynamic gadolinium-enhanced images. Blinded reader comparison of the T2-weighted images and gadolinium-enhanced images was performed. Hypervascular hemangiomas enhanced to a greater degree than hypervascular malignant liver lesions on the early phase gadolinium-enhanced images. Perilesional parenchymal enhancement was demonstrated in five cases of rapidly enhancing hemangiomas. Signal intensity and contrast-to-noise ratios on the heavily T2-weighted images of the hemangiomas were significantly greater than that of the hypervascular malignant lesions (P < .05). Hemangiomas were differentiated from the hypervascular malignant liver lesions with high accuracy (97-100%) by three blinded readers based on the T2-weighted images. A subset of hemangiomas have atypical rapid diffuse enhancement on dynamic gadolinium-enhanced images. These atypical hemangiomas can be distinguished from hypervascular malignant liver lesions on T2-weighted MR images. PMID:9400846

  7. Multiphasic contrast-enhanced CT and MRI findings of adult mesoblastic nephroma: A report of two cases

    PubMed Central

    Ding, Yuqin; He, Deming; Zhou, Jianjun; Zeng, Mengsu

    2013-01-01

    Mesoblastic nephroma (MN) presenting in an adult is extremely rare. The computed tomography (CT) and magnetic resonance imaging (MRI) features of this tumor in adulthood have not been widely reported. We present two additional cases of adult MN and describe the multiphasic contrast-enhanced CT and MRI findings. PMID:23986620

  8. Quantitative Evaluation of Enhancement Patterns in Focal Solid Liver Lesions with Gd-EOB-DTPA-Enhanced MRI

    PubMed Central

    Haimerl, Michael; Wächtler, Max; Zeman, Florian; Verloh, Niklas; Platzek, Ivan; Schreyer, Andreas Georg; Stroszczynski, Christian; Wiggermann, Philipp

    2014-01-01

    Purpose The objective was to investigate the dynamic enhancement patterns in focal solid liver lesions after the administration of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) by means of dynamic magnetic resonance imaging (MRI) including hepatobiliary phase (HP) images 20 min after Gd-EOB-DTPA administration. Materials and Methods Non-enhanced T1/T2-weighted as well as dynamic magnetic resonance (MR) images during the arterial phase (AP), the portal venous phase (PVP), the late phase (LP), and the HP (20 min) were obtained from 83 patients (54 male, 29 female, mean age 62.01 years) with focal solid liver lesions. MRI was conducted by means of a 1.5-T system for 63 patients with malignant liver lesions (HCCs: n?=?34, metastases: n?=?29) and for 20 patients with benign liver lesions (FNH lesions: n?=?14, hemangiomas: n?=?3, adenomas: n?=?3). For quantitative analysis, signal-to-noise ratios (SNR), contrast enhancement ratios (CER), lesion-to-liver contrast ratios (LLC), and signal intensity (SI) ratios were measured. Results The SNR of liver parenchyma significantly increased in each dynamic phase after Gd-EOB-DTPA administration compared to the SNR of non-enhanced images (p<0.001). The CER of HCCs and metastases significantly decreased between LP and HP images (p?=?0.0011, p<0.0001). However, FNH lesions did not show any significant difference, whereas an increased CER was found in hemangiomas. The mean LLCs of FNH lesions were significantly higher than those of HCCs and metastases. The LLC values of hemangiomas remained negative during the entire time course, whereas the LLC of adenomas indicated hyperintensity from the AP to the LP. Furthermore, adenomas showed hypointensity in HP images. Conclusion Gd-EOB-DTPA-enhanced MRI may help diagnose focal solid liver lesions by evaluating their enhancement patterns. PMID:24950259

  9. MRI-guided gas bubble enhanced ultrasound heating in in vivo rabbit thigh.

    PubMed

    Sokka, S D; King, R; Hynynen, K

    2003-01-21

    In this study, we propose a focused ultrasound surgery protocol that induces and then uses gas bubbles at the focus to enhance the ultrasound absorption and ultimately create larger lesions in vivo. MRI and ultrasound visualization and monitoring methods for this heating method are also investigated. Larger lesions created with a carefully monitored single ultrasound exposure could greatly improve the speed of tumour coagulation with focused ultrasound. All experiments were performed under MRI (clinical, 1.5 T) guidance with one of two eight-sector, spherically curved piezoelectric transducers. The transducer, either a 1.1 or 1.7 MHz array, was driven by a multi-channel RF driving system. The transducer was mounted in an MRI-compatible manual positioning system and the rabbit was situated on top of the system. An ultrasound detector ring was fixed with the therapy transducer to monitor gas bubble activity during treatment. Focused ultrasound surgery exposures were delivered to the thighs of seven New Zealand while rabbits. The experimental, gas-bubble-enhanced heating exposures consisted of a high amplitude 300 acoustic watt, half second pulse followed by a 7 W, 14 W or 21 W continuous wave exposure for 19.5 s. The respective control sonications were 20 s exposures of 14 W, 21 W and 28 W. During the exposures, MR thermometry was obtained from the temperature dependency of the proton resonance frequency shift. MRT2-enhanced imaging was used to evaluate the resulting lesions. Specific metrics were used to evaluate the differences between the gas-bubble-enhanced exposures and their respective control sonications: temperatures with respect to time and space, lesion size and shape, and their agreement with thermal dose predictions. The bubble-enhanced exposures showed a faster temperature rise within the first 4 s and higher overall temperatures than the sonications without bubble formation. The spatial temperature maps and the thermal dose maps derived from the MRI thermometry closely correlated with the resulting lesion as examined by T2-weighted imaging. The lesions created with the gas-bubble-enhanced heating exposures were 2-3 times larger by volume, consistently more spherical in shape and closer to the transducer than the control exposures. The study demonstrates that gas bubbles can reliably be used to create significantly larger lesions in vivo. MRI thermometry techniques were successfully used to monitor the thermal effects mediated by the bubble-enhanced exposures. PMID:12587906

  10. The Use of MRI Modeling to Enhance Osteochondral Transfer in Segmental Kienböck’s Disease

    PubMed Central

    Barber, Lauren; Virtue, Patrick; Lipman, Joseph P.; Hotchkiss, Robert J.; Potter, Hollis G.

    2012-01-01

    Kienböck’s disease, defined as avascular necrosis of the lunate, is a relatively rare condition with a poorly understood etiology. Conservative and invasive treatments for Kienböck’s disease exist, including wrist immobilization, surgical joint-leveling procedures, vascularized bone grafting, proximal row carpectomy, and total wrist arthrodesis. Staging Kienböck’s disease using radiography assumes near complete avascularity of the lunate. The staging distinguishes only the “state of collapse” in an ordinal classification scheme and does not allow localization or indicate partial involvement of the lunate, which the image contrast from MRI may provide. In this short communication, we report the treatment of a patient’s Kienböck’s disease by combining MRI with mathematical modeling to optimize the congruency between the curvature of donor and recipient sites of an autologous osteoarticular plug transfer. Follow-up MRI and radiographs at 1 year postoperatively demonstrated gradual graft incorporation and bone healing. The purpose of this study was to describe the feasibility of a novel surgical technique. The results indicate that donor site selection for autologous osteoarticular transfer using a quantitative evaluation of articular surface curvature may be beneficial for optimizing the likelihood for restoring the radius of curvature and thus joint articulation following cartilage repair.

  11. Follow-up design of unexpected enhancing lesions on preoperative MRI of breast cancer patients

    PubMed Central

    Cheung, Joo-Yeon; Moon, Jin Hee

    2015-01-01

    PURPOSE We aimed to analyze the characteristics and long-term follow-up results of unexpected enhancing lesions on preoperative magnetic resonance imaging (MRI) of breast cancer patients. METHODS From August 2007 through February 2010, second-look ultrasound (SLUS) was recommended for 84 of 312 breast cancer patients having unexpected enhancing lesions on MRI. SLUS was performed for 85 unexpected enhancing lesions in 72 patients. We performed a retrospective review to determine the size, lesion type, enhancement kinetic curve, and location in relation to the index cancer. We obtained the pathologic outcome of the detected lesions and in case of a negative finding on SLUS, we performed follow-up examinations for at least two years. RESULTS Of 85 unexpected lesions, 72 (85%) were detected on SLUS. In total, 41 lesions (56.9%) were confirmed as malignant and 31 lesions (43.6%) as benign. Cancer rate was statistically higher in lesions having type III enhancement pattern, located at the same quadrant as the index cancer. However, no significant association was observed between the cancer rate and the lesion size and type. None of the 13 negative cases on SLUS developed cancer on follow-up. CONCLUSION In case of unexpected enhancing lesions on preoperative MRI of breast cancer patients, SLUS can be useful to find out the matched lesion. Lesions with type III enhancement pattern or those located at the same quadrant as the index cancer should be considered as a separate cancer. In the absence of any suspicious findings on SLUS, patient may be followed up with confidence. PMID:25430525

  12. Interpreting therapeutic effect in multiple sclerosis via MRI contrast enhancing lesions: now you see them, now you don't.

    PubMed

    Leppert, Ilana R; Narayanan, S; Araújo, D; Giacomini, P S; Lapierre, Y; Arnold, D L; Pike, G B

    2014-04-01

    Gadolinium (Gd) enhancement of multiple sclerosis (MS) lesions on MRI scans is a commonly used outcome measure in therapeutic trials. However, enhancement depends on MRI acquisition parameters that might significantly alter detectability. We investigated how the difference in blood-brain barrier (BBB) permeability threshold between MRI protocols affects lesion detection and apparent enhancement time using dynamic-contrast-enhanced (DCE) MRI. We examined fourty-four relapsing-remitting MS patients with two MRI protocols: 'standard sensitivity' (SS) (1.5 T, single-dose Gd) and 'high sensitivity' (HS) (3 T, triple-dose Gd, delayed acquisition). Eleven patients had at least one enhancing lesion and completed the 1-month follow-up. We acquired DCE-MRI during the HS protocol and calculated BBB permeability. Sixty-five lesions were enhanced with the SS vs. 135 with the HS protocol. The detection threshold of the HS was significantly lower than that of the SS protocol (K trans = 2.64 vs. 4.00E-3 min(-1), p < 0.01). Most lesions (74 %) were in the recovery phase; none were in the onset phase and 26 % were at the peak of enhancement. The estimated duration of detectability with the HS protocol was significantly longer than for the SS protocol (6-12 weeks vs. 3 weeks). Our observations on the protocol-dependent threshold for detection and time-course help explain discrepancies in the observed effects of anti-inflammatory therapies on MS lesions. PMID:24570281

  13. 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.

  14. Precision analysis of kinetic modelling estimates in dynamic contrast enhanced MRI

    Microsoft Academic Search

    Dieter De Naeyer; Yves De Deene; Wim P. Ceelen; Patrick Segers; Pascal Verdonck

    2011-01-01

    Object  Dynamic contrast enhanced MRI and pharmacokinetic modelling provide a powerful tool for tumour diagnosis and treatment evaluation.\\u000a However, several studies show low reproducibility of the technique and poor precision of the transendothelial transfer constant\\u000a K\\u000a trans. This work proposes a theoretical framework describing how finite signal-noise-ratio (SNR) in the MR images is propagated\\u000a throughout the measurement protocol to uncertainty on

  15. 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

  16. Octreotide Exerts Only Acute, but No Sustained, Effects on MRI Enhancement of Liver Metastases in Carcinoid Syndrome

    Microsoft Academic Search

    Menno T. Zomerhuis; Shahid M. Hussain; Richard A. Feelders; Aart-Jan van der Lely; Wouter W. de Herder

    2005-01-01

    We have investigated the acute and sustained hemodynamic effects of octreotide on hepatic metastases of midgut carcinoids using contrast-enhanced dynamic magnetic resonance imaging (MRI). Seven patients with the carcinoid syndrome and metastasized midgut carcinoid tumors underwent functional dynamic multi-phase gadolinium-enhanced MRI of selected liver metastases at baseline and 60 min after the subcutaneous (s.c.) administration of 100 ?g octreotide, and

  17. Ketamine and fMRI BOLD signal: distinguishing between effects mediated by change in blood flow versus change in cognitive state.

    PubMed

    Abel, Kathryn M; Allin, Matthew P G; Kucharska-Pietura, Katarzyna; Andrew, Chris; Williams, Steve; David, Anthony S; Phillips, Mary L

    2003-02-01

    No human fMRI studies have examined ketamine effects on the BOLD signal change associated with cognitive task performance. We wished to distinguish between effects on 1) cerebral blood flow, with resultant change in BOLD signal; and 2) cognition and neural mechanisms underlying BOLD signal change associated with task performance. Eight right-handed men (mean age 28.75 years) received ketamine or saline i.v. in a randomized, double-blind manner (bolus 0.23 mg/kg; 0.5 mg/kg over 45 min to a maximum 1 hr). Subjects viewed 10 alternating 30-sec blocks of faces with neutral expressions and a fixation cross and discriminated gender of faces. Gradient echo echoplanar images were acquired on a GE Signa 1.5 T Neurovascular system. One hundred T2-weighted images depicting BOLD contrast were acquired over 5 min (for each task) at each of 14 near-axial noncontiguous 7-mm thick planes. Ketamine significantly increased dissociative phenomena and negative symptoms, but did not affect performance of the gender discrimination task. Significant BOLD signal change was demonstrated predominantly in occipitotemporal cortex with both ketamine and placebo. Only two clusters in middle occipital gyrus (BA 18) and precentral gyrus (BA 4) showed significantly decreased BOLD signal change during ketamine compared to placebo. BOLD signal change was not significantly greater in any region during ketamine. Our findings demonstrate subtle rather than major differences between the effects of ketamine and placebo upon the BOLD signal change during perception of face-non face contrast. We suggest that they represent task-dependent effects of the drug/placebo, rather than task-independent effects of the drug per se, and indicate that the effects of ketamine on cerebral blood flow are predominantly focal and task-dependent, rather than global and task-independent. PMID:12518293

  18. Manganese-enhanced MRI visualizes V1 in the non-human primate visual cortex.

    PubMed

    Bock, Nicholas A; Kocharyan, Ara; Silva, Afonso C

    2009-08-01

    MRI at 7 Tesla has been used to investigate the accumulation of manganese in the occipital cortex of common marmoset monkeys (Callithrix jacchus) after administering four fractionated injections of 30 mg/kg MnCl(2) . 4H(2)O in the tail vein. We found a statistically significant decrease in T(1) in the primary (V1) and secondary (V2) areas of the visual cortex caused by an accumulation of manganese. The larger T(1) shortening in V1 (DeltaT(1) = 640 ms) relative to V2 (DeltaT(1) = 490 ms) allowed us to robustly detect the V1/V2 border in vivo using heavily T(1)-weighted MRI. Furthermore, the dorso-medial (DM) and middle-temporal (MT) areas of the visual pathway could be identified by their T(1)-weighted enhancement. We showed by comparison to histological sections stained for cytochrome oxidase (CO) activity that the extent of V1 is accurately identified throughout the visual cortex by manganese-enhanced MRI (MEMRI). This provides a means of visualizing functional cortical regions in vivo and could be used in longitudinal studies of phenomena such as cortical plasticity, and for non-destructive localization of cortical regions to guide in the implementation of functional techniques. PMID:19322808

  19. NOTE: Characterizing early contrast uptake of ductal carcinoma in situ with high temporal resolution dynamic contrast-enhanced MRI of the breast: a pilot study

    NASA Astrophysics Data System (ADS)

    Jansen, S. A.; Fan, X.; Medved, M.; Abe, H.; Shimauchi, A.; Yang, C.; Zamora, M.; Foxley, S.; Olopade, O. I.; Karczmar, G. S.; Newstead, G. M.

    2010-10-01

    Improvements in the reliable diagnosis of preinvasive ductal carcinoma in situ (DCIS) by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) are needed. In this study, we present a new characterization of early contrast kinetics of DCIS using high temporal resolution (HiT) DCE-MRI and compare it with other breast lesions and normal parenchyma. Forty patients with mammographic calcifications suspicious for DCIS were selected for HiT imaging using T1-weighted DCE-MRI with ~7 s temporal resolution for 90 s post-contrast injection. Pixel-based and whole-lesion kinetic curves were fit to an empirical mathematical model (EMM) and several secondary kinetic parameters derived. Using the EMM parameterized and fitted concentration time curve for subsequent analysis allowed for calculation of kinetic parameters that were less susceptible to fluctuations due to noise. The parameters' initial area under the curve (iAUC) and contrast concentration at 1 min (C1 min) provided the highest diagnostic accuracy in the task of distinguishing pathologically proven DCIS from normal tissue. There was a trend for DCIS lesions with solid architectural pattern to exhibit a negative slope at 1 min (i.e. increased washout rate) compared to those with a cribriform pattern (p < 0.04). This pilot study demonstrates the feasibility of quantitative analysis of early contrast kinetics at high temporal resolution and points to the potential for such an analysis to improve the characterization of DCIS.

  20. The Added Diagnostic Value of Dynamic Contrast-Enhanced MRI at 3.0 T in Nonpalpable Breast Lesions

    PubMed Central

    Merckel, Laura G.; Verkooijen, Helena M.; Peters, Nicky H. G. M.; Mann, Ritse M.; Veldhuis, Wouter B.; Storm, Remmert K.; Weits, Teun; Duvivier, Katya M.; van Dalen, Thijs; Mali, Willem P. Th. M.; Peeters, Petra H. M.; van den Bosch, Maurice A. A. J.

    2014-01-01

    Objective To investigate the added diagnostic value of 3.0 Tesla breast MRI over conventional breast imaging in the diagnosis of in situ and invasive breast cancer and to explore the role of routine versus expert reading. Materials and Methods We evaluated MRI scans of patients with nonpalpable BI-RADS 3–5 lesions who underwent dynamic contrast-enhanced 3.0 Tesla breast MRI. Initially, MRI scans were read by radiologists in a routine clinical setting. All histologically confirmed index lesions were re-evaluated by two dedicated breast radiologists. Sensitivity and specificity for the three MRI readings were determined, and the diagnostic value of breast MRI in addition to conventional imaging was assessed. Interobserver reliability between the three readings was evaluated. Results MRI examinations of 207 patients were analyzed. Seventy-eight of 207 (37.7%) patients had a malignant lesion, of which 33 (42.3%) patients had pure DCIS and 45 (57.7%) invasive breast cancer. Sensitivity of breast MRI was 66.7% during routine, and 89.3% and 94.7% during expert reading. Specificity was 77.5% in the routine setting, and 61.0% and 33.3% during expert reading. In the routine setting, MRI provided additional diagnostic information over clinical information and conventional imaging, as the Area Under the ROC Curve increased from 0.76 to 0.81. Expert MRI reading was associated with a stronger improvement of the AUC to 0.87. Interobserver reliability between the three MRI readings was fair and moderate. Conclusions 3.0 T breast MRI of nonpalpable breast lesions is of added diagnostic value for the diagnosis of in situ and invasive breast cancer. PMID:24713637

  1. fMRI feedback enhances emotion regulation as evidenced by a reduced amygdala response.

    PubMed

    Sarkheil, Pegah; Zilverstand, Anna; Kilian-Hütten, Niclas; Schneider, Frank; Goebel, Rainer; Mathiak, Klaus

    2015-03-15

    Deficits in emotion regulation are a prominent feature of psychiatric conditions and a promising target for treatment. For instance, cognitive reappraisal is regarded as an effective strategy for emotion regulation. Neurophysiological models have established the lateral prefrontal cortex (LPFC) as a key structure in the regulation of emotion processing through modulations of emotion-eliciting structures such as the amygdala. Feedback of the LPFC activity by real-time functional magnetic resonance (fMRI) may thus enhance the efficacy of cognitive reappraisal. During cognitive reappraisal of aversive visual stimuli, LPFC activity was fed back to the experimental group, whereas control participants received no such information. As a result, during reappraisal, amygdala activity was lower in the experimental group than in the controls. Furthermore, an increase of inter-hemispheric functional connectivity emerged in the feedback group. The current study extends the neurofeedback literature by suggesting that fMRI feedback can modify brain activity during a given task. PMID:25461265

  2. 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 ?l 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.

  3. Simultaneous imaging of tumor oxygenation and microvascular permeability using Overhauser enhanced MRI

    PubMed Central

    Matsumoto, Shingo; Yasui, Hironobu; Batra, Sonny; Kinoshita, Yuichi; Bernardo, Marcelino; Munasinghe, Jeeva P.; Utsumi, Hideo; Choudhuri, Rajani; Devasahayam, Nallathamby; Subramanian, Sankaran; Mitchell, James B.; Krishna, Murali C.

    2009-01-01

    Architectural and functional abnormalities of blood vessels are a common feature in tumors. A consequence of increased vascular permeability and concomitant aberrant blood flow is poor delivery of oxygen and drugs, which is associated with treatment resistance. In the present study, we describe a strategy to simultaneously visualize tissue oxygen concentration and microvascular permeability by using a hyperpolarized 1H-MRI, known as Overhauser enhanced MRI (OMRI), and an oxygen-sensitive contrast agent OX63. Substantial MRI signal enhancement was induced by dynamic nuclear polarization (DNP). The DNP achieved up to a 7,000% increase in MRI signal at an OX63 concentration of 1.5 mM compared with that under thermal equilibrium state. The extent of hyperpolarization is influenced mainly by the local concentration of OX63 and inversely by the tissue oxygen level. By collecting dynamic OMRI images at different hyperpolarization levels, local oxygen concentration and microvascular permeability of OX63 can be simultaneously determined. Application of this modality to murine tumors revealed that tumor regions with high vascular permeability were spatio-temporally coincident with hypoxia. Quantitative analysis of image data from individual animals showed an inverse correlation between tumor vascular leakage and median oxygen concentration. Immunohistochemical analyses of tumor tissues obtained from the same animals after OMRI experiments demonstrated that lack of integrity in tumor blood vessels was associated with increased tumor microvascular permeability. This dual imaging technique may be useful for the longitudinal assessment of changes in tumor vascular function and oxygenation in response to chemotherapy, radiotherapy, or antiangiogenic treatment. PMID:19815528

  4. Simultaneous imaging of tumor oxygenation and microvascular permeability using Overhauser enhanced MRI.

    PubMed

    Matsumoto, Shingo; Yasui, Hironobu; Batra, Sonny; Kinoshita, Yuichi; Bernardo, Marcelino; Munasinghe, Jeeva P; Utsumi, Hideo; Choudhuri, Rajani; Devasahayam, Nallathamby; Subramanian, Sankaran; Mitchell, James B; Krishna, Murali C

    2009-10-20

    Architectural and functional abnormalities of blood vessels are a common feature in tumors. A consequence of increased vascular permeability and concomitant aberrant blood flow is poor delivery of oxygen and drugs, which is associated with treatment resistance. In the present study, we describe a strategy to simultaneously visualize tissue oxygen concentration and microvascular permeability by using a hyperpolarized (1)H-MRI, known as Overhauser enhanced MRI (OMRI), and an oxygen-sensitive contrast agent OX63. Substantial MRI signal enhancement was induced by dynamic nuclear polarization (DNP). The DNP achieved up to a 7,000% increase in MRI signal at an OX63 concentration of 1.5 mM compared with that under thermal equilibrium state. The extent of hyperpolarization is influenced mainly by the local concentration of OX63 and inversely by the tissue oxygen level. By collecting dynamic OMRI images at different hyperpolarization levels, local oxygen concentration and microvascular permeability of OX63 can be simultaneously determined. Application of this modality to murine tumors revealed that tumor regions with high vascular permeability were spatio-temporally coincident with hypoxia. Quantitative analysis of image data from individual animals showed an inverse correlation between tumor vascular leakage and median oxygen concentration. Immunohistochemical analyses of tumor tissues obtained from the same animals after OMRI experiments demonstrated that lack of integrity in tumor blood vessels was associated with increased tumor microvascular permeability. This dual imaging technique may be useful for the longitudinal assessment of changes in tumor vascular function and oxygenation in response to chemotherapy, radiotherapy, or antiangiogenic treatment. PMID:19815528

  5. 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…

  6. Mapping Tumor Hypoxia In Vivo Using Pattern Recognition of Dynamic Contrast-enhanced MRI Data12

    PubMed Central

    Stoyanova, Radka; Huang, Kris; Sandler, Kiri; Cho, HyungJoon; Carlin, Sean; Zanzonico, Pat B; Koutcher, Jason A; Ackerstaff, Ellen

    2012-01-01

    In solid tumors, hypoxia contributes significantly to radiation and chemotherapy resistance and to poor outcomes. The “gold standard” pO2 electrode measurements of hypoxia in vivo are unsatisfactory because they are invasive and have limited spatial coverage. Here, we present an approach to identify areas of tumor hypoxia using the signal versus time curves of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data as a surrogate marker of hypoxia. We apply an unsupervised pattern recognition (PR) technique to determine the differential signal versus time curves associated with different tumor microenvironmental characteristics in DCE-MRI data of a preclinical cancer model. Well-perfused tumor areas are identified by rapid contrast uptake followed by rapid washout; hypoxic areas, which are regions of reduced vascularization, are identified by delayed contrast signal buildup and washout; and necrotic areas exhibit slow or no contrast uptake and no discernible washout over the experimental observation. The strength of the PR concept is that it captures the pixel-enhancing behavior in its entirety—during both contrast agent uptake and washout—and thus, subtleties in the temporal behavior of contrast enhancement related to features of the tumor microenvironment (driven by vascular changes) may be detected. The assignment of the tumor compartments/microenvironment to well vascularized, hypoxic, and necrotic is validated by comparison to data previously obtained using complementary imaging modalities. The proposed novel analysis approach has the advantage that it can be readily translated to the clinic, as DCE-MRI is used routinely for the identification of tumors in patients, is widely available, and easily implemented on any clinical magnet. PMID:23326621

  7. Combined prostate diffusion tensor imaging and dynamic contrast enhanced MRI at 3T--quantitative correlation with biopsy.

    PubMed

    Kozlowski, Piotr; Chang, Silvia D; Meng, Ran; Mädler, Burkhard; Bell, Robert; Jones, Edward C; Goldenberg, S Larry

    2010-06-01

    The purpose of this work was to compare diagnostic accuracy of Diffusion Tensor Imaging (DTI), dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) and their combination in diagnosing prostate cancer. Twenty-five patients with clinical suspicion of prostate cancer underwent MRI, prior to transrectal ultrasound-guided biopsies. MRI data were correlated to biopsy results. Logistic regression models were constructed for the DTI parameters, DCE MRI parameters, and their combination. The areas under the receiver operator characteristic curves (AUC) were compared between the models. The nonparametric Wilcoxon signed rank test was used for statistical analysis. The sensitivity and specificity values were respectively 81% (74-87%) and 85% (79-90%) for DTI and 63% (55-70%) and 90% (85-94%) for DCE. The combination "DTI or DCE MRI" had 100% (97-100%) sensitivity and 77% (69-83%) specificity, while "DTI and DCE MRI" had 44% (37-52%) sensitivity and 98% (94-100%) specificity. The AUC for DTI+DCE parameters was significantly higher than that for either DTI (0.96 vs. 0.92, P=.0143) or DCE MRI parameters (0.96 vs. 0.87, P=.00187) alone. In conclusion, the combination of DTI and DCE MRI has significantly better accuracy in prostate cancer diagnosis than either technique alone. PMID:20392586

  8. Dynamic Contrast Enhanced-MRI with Extravasating Contrast Reagent: Rat Cerebral Glioma Blood Volume Determination

    PubMed Central

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

    2010-01-01

    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

  9. Evaluation of an AIF correction algorithm for dynamic susceptibility contrast-enhanced perfusion MRI.

    PubMed

    Brunecker, Peter; Endres, Matthias; Nolte, Christian H; Schultze, Jörg; Wegener, Susanne; Jungehülsing, Gerhard Jan; Müller, Bianca; Kerskens, Christian M; Fiebach, Jochen B; Villringer, Arno; Steinbrink, Jens

    2008-07-01

    For longitudinal studies in patients suffering from cerebrovascular diseases the poor reproducibility of perfusion measurements via dynamic susceptibility-weighted contrast-enhanced MRI (DSC-MRI) is a relevant concern. We evaluate a novel algorithm capable of overcoming limitations in DSC-MRI caused by partial volume and saturation issues in the arterial input function (AIF) by a blood flow stimulation-study. In 21 subjects, perfusion parameters before and after administration of blood flow stimulating L-arginine were calculated utilizing a block-circulant singular value decomposition (cSVD). A total of two different raters and three different rater conditions were employed to select AIFs: Besides 1) an AIF selection by an experienced rater, a beginner rater applied a steady state-oriented strategy, returning; 2) raw; and 3) corrected AIFs. Highly significant changes in regional cerebral blood flow (rCBF) by 9.0% (P < 0.01) could only be found when the AIF correction was performed. To further test for improved reproducibility, in a subgroup of seven subjects the baseline measurement was repeated 6 weeks after the first examination. In this group as well, using the correction algorithm decreased the SD of the difference between the two baseline measurements by 42%. PMID:18581417

  10. Novel Stochastic Framework for Accurate Segmentation of Prostate in Dynamic Contrast Enhanced MRI

    NASA Astrophysics Data System (ADS)

    Firjany, Ahmad; Elnakib, Ahmed; El-Baz, Ayman; Gimel'Farb, Georgy; El-Ghar, Mohamed Abo; Elmagharby, Adel

    Prostate segmentation is an essential step in developing any non-invasive Computer-Assisted Diagnostic (CAD) system for the early diagnosis of prostate cancer using Dynamic Contrast Enhancement Magnetic Resonance Images (DCE-MRI). In this paper we propose a novel approach for segmenting the prostate region from DCE-MRI based on using a graph cut framework to optimize a new energy function consists of three descriptors: (i) 1 st -order visual appearance descriptors of the DCE-MRI; (ii) a spatially invariant 2 nd -order homogeneity descriptor, and (iii) a prostate shape descriptor. The shape prior is learned from a subset of co-aligned training images. The visual appearances are described with marginal gray level distributions obtained by separating their mixture over the image. The spatial interactions between the prostate pixels are modeled by a 2 nd -order translation and rotation invariant Markov-Gibbs random field of object / background labels with analytically estimated potentials. Experiments with prostate DCE-MR images confirm robustness and accuracy of the proposed approach.

  11. 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

  12. Magnetic resonance imaging contrast-enhanced relaxometry of breast tumors: an MRI multicenter investigation concerning 100 patients

    Microsoft Academic Search

    Pierre-Antoine Eliat; Véronique Dedieu; Catherine Bertino; Véronique Bouté; Joëlle Lacroix; Jean-Marc Constans; Brigitte de Korvin; Catherine Vincent; Corinne Bailly; Francis Joffre; Jacques de Certaines; Dominique Vincensini

    2004-01-01

    Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using extracellular contrast agents has proved to be useful for the characterization of breast tumors. DCE-MRI has demonstrated a high sensitivity (around 95%) but a rather poor and controversial specificity, varying, according to the different studies, from 45% to 90%. In order to increase (a) the specificity and (b) the robustness of this quantitative

  13. 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.

  14. Vascular changes caused by deep brain stimulation using double-dose gadolinium-enhanced brain MRI

    PubMed Central

    Choi, Byeong Sam; Kim, Yong Hwan; Jeon, Sang Ryong

    2014-01-01

    We retrospectively analyzed the clinical data of 32 patients with medically intractable idiopathic Parkinson's disease who had undergone staged bilateral deep brain stimulation of the subthalamic nuclei from January 2007 to May 2011. The vascularture of the patients who received two deep brain stimulations was detected using double-dose gadolinium-enhanced brain MRI. The dimensions of straight sinus, superior sagittal sinus, ipsilateral internal cerebral vein in the thalamic branch and ipsilateral anterior caudate vein were reduced. These findings demonstrate that bilateral deep brain stimulation of the subthalamic nuclei affects cerebral venous blood flow. PMID:25206812

  15. 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.

  16. A data-driven approach to prostate cancer detection from dynamic contrast enhanced MRI.

    PubMed

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

    2015-04-01

    Magnetic resonance imaging (MRI), particularly dynamic contrast enhanced (DCE) imaging, has shown great potential in prostate cancer diagnosis and staging. In the current practice of DCE-MRI, diagnosis is based on quantitative parameters extracted from the series of T1-weighted images acquired after the injection of a contrast agent. To calculate these parameters, a pharmacokinetic model is fitted to the T1-weighted intensities. Most models make simplistic assumptions about the perfusion process. Moreover, these models require accurate estimation of the arterial input function, which is challenging. In this work we propose a data-driven approach to characterization of the prostate tissue that uses the time series of DCE T1-weighted images without pharmacokinetic modeling. This approach uses a number of model-free empirical parameters and also the principal component analysis (PCA) of the normalized T1-weighted intensities, as features for cancer detection from DCE MRI. The optimal set of principal components is extracted with sparse regularized regression through least absolute shrinkage and selection operator (LASSO). A support vector machine classifier was used with leave-one-patient-out cross validation to determine the ability of this set of features in cancer detection. Our data is obtained from patients prior to radical prostatectomy and the results are validated based on histological evaluation of the extracted specimens. Our results, obtained on 449 tissue regions from 16 patients, show that the proposed data-driven features outperform the traditional pharmacokinetic parameters with an area under ROC of 0.86 for LASSO-isolated PCA parameters, compared to 0.78 for pharmacokinetic parameters. This shows that our novel approach to the analysis of DCE data has the potential to improve the multiparametric MRI protocol for prostate cancer detection. PMID:25060941

  17. A Dedicated Automated Injection System for Dynamic Contrast-Enhanced MRI Experiments in Mice

    PubMed Central

    Sedlacik, Jan; Myers, Adrianne; Loeffler, Ralf B.; Williams, Regan F.; Davidoff, Andrew M.; Hillenbrand, Claudia M.

    2012-01-01

    Purpose To develop a reproducible small-animal dynamic contrast-enhanced (DCE) MRI set-up for mice through which volumes <100?L can be accurately and safely injected and to test this set-up via DCE measurements in resting muscle and tumor tissue. Materials and Methods The contrast agent (CA) injection system comprised 2 MR-compatible syringe pumps placed 50cm from the 7T magnet bore where the fringe field is about 40mT. Microbore tubing and T-connector, close to the injection site, minimized dead volume (<10?L). For DCE-MRI measurements in 8 CB-17 SCID mice with 1500–2500mm3 large orthotopic neuroblastoma, a bolus of 10-fold-diluted Gd-DTPA CA solution (0.1mmol/kg) was delivered (5?L/s), followed by a 50?L saline flush. Retro-orbital injections were given instead of tail vein injections, since the peripheral vasculature was reduced because of large tumor burden. Results The CA injection was successful in 19 of 24 experiments. Optical assessment showed minimal dispersion of ink-colored CA bolus. Mean (±SD) pharmacokinetic parameters retrieved from DCE-MRI examinations in resting muscle (Ktrans=0.038±0.025min?1, kep=0.66±0.48min?1, ve=0.060±0.014, vp=0.033±0.021) and tumor (Ktrans=0.082±0.071min?1, kep=0.82±0.80min?1, ve=0.121±0.075, vp=0.093±0.051) agreed with those reported previously. Conclusion We successfully designed and implemented a DCE-MRI set-up system with short injection lines and low dead volume. The system can be used at any field strength with the syringe pumps placed at a sufficiently low fringe field (<40mT). PMID:23001593

  18. Convection-enhanced delivery of maghemite nanoparticles: Increased efficacy and MRI monitoring

    PubMed Central

    Perlstein, Benny; Ram, Zvi; Daniels, Dianne; Ocherashvilli, Aharon; Roth, Yiftach; Margel, Shlomo; Mardor, Yael

    2008-01-01

    Convection-enhanced drug delivery (CED) is a novel approach to delivering drugs into brain tissue. Drugs are delivered continuously via a catheter, enabling large volume distributions of high drug concentrations with minimum systemic toxicity. Previously we demonstrated that CED formation/extent of small molecules may be significantly improved by increasing infusate viscosities. In this study we show that the same methodology can be applied to monodispersed maghemite nanoparticles (MNPs). For this purpose we used a normal rat brain model and performed CED of MNPs over short infusion times. By adding 3% sucrose or 3%–6% polyethylene glycol (PEG; molecular weight 400) to saline containing pristine MNPs, we increased infusate viscosity and obtained increased CED efficacy. Further, we show that CED of dextran-coated MNPs (dextran-MNPs) resulted in increased efficacy over pristine MNPs (p < 0.007). To establish the use of MRI for reliable depiction of MNP distribution, CED of fluorescent dextran-MNPs was performed, demonstrating a significant correlation between the distributions as depicted by MRI and spectroscopic images (r2 = 0.74, p < 0.0002). MRI follow-up showed that approximately 80%–90% of the dextran-MNPs were cleared from the rat brain within 40 days of CED; the rest remained in the brain for more than 4 months. MNPs have been tested for applications such as targeted drug delivery and controlled drug release and are clinically used as a contrast agent for MRI. Thus, combining the CED method with the advantages of MNPs may provide a powerful tool to treat and monitor brain tumors. PMID:18316474

  19. Targeted Multifunctional Nanoparticles cure and image Brain Tumors: Selective MRI Contrast Enhancement and Photodynamic Therapy

    NASA Astrophysics Data System (ADS)

    Kopelman, Raoul

    2008-03-01

    Aimed at targeted therapy and imaging of brain tumors, our approach uses targeted, multi-functional nano-particles (NP). A typical nano-particle contains a biologically inert, non-toxic matrix, biodegradable and bio-eliminable over a long time period. It also contains active components, such as fluorescent chemical indicators, photo-sensitizers, MRI contrast enhancement agents and optical imaging dyes. In addition, its surface contains molecular targeting units, e.g. peptides or antibodies, as well as a cloaking agent, to prevent uptake by the immune system, i.e. enabling control of the plasma residence time. These dynamic nano-platforms (DNP) contain contrast enhancement agents for the imaging (MRI, optical, photo-acoustic) of targeted locations, i.e. tumors. Added to this are targeted therapy agents, such as photosensitizers for photodynamic therapy (PDT). A simple protocol, for rats implanted with human brain cancer, consists of tail injection with DNPs, followed by 5 min red light illumination of the tumor region. It resulted in excellent cure statistics for 9L glioblastoma.

  20. Advantageous application of a surface coil to EPR irradiation in overhauser-enhanced MRI.

    PubMed

    Matsumoto, Shingo; Yamada, Kenichi; Hirata, Hiroshi; Yasukawa, Keiji; Hyodo, Fuminori; Ichikawa, Kazuhiro; Utsumi, Hideo

    2007-04-01

    The present study describes the advantageous application of a surface coil to electron paramagnetic resonance (EPR) irradiation in Overhauser-enhanced MRI (OMRI). OMRI is a double-resonance method for imaging free radicals based on the Overhauser effect. Proton NMR images are recorded without and with EPR irradiation of the free radical resonance, which results in a difference proton image that shows signal enhancement in spatial regions that contain the free radical. To obtain good signal enhancement in OMRI, very high RF power and a long EPR irradiation time are required. To improve sensitivity and shorten the image acquisition time, especially for localized (and topical) applications, we developed and tested a surface-coil-type EPR irradiation coil. Theoretical calculations and experimental data showed that EPR irradiation through the surface coil could ameliorate the localized Overhauser enhancement, which was related to the ratio of B(1) surface coil/B(1) volume coil in the region of interest (ROI), as expected. The increased sensitivity could also be converted into a shortened EPR irradiation time, resulting in fast data acquisition. For biomedical applications, the use of a surface coil (as opposed to a conventional volume coil) could decrease the total RF power deposition in the sample required to obtain the same Overhauser enhancement in the ROI. PMID:17390363

  1. Volumetry of [ 11 C]-methionine PET uptake and MRI contrast enhancement in patients with recurrent glioblastoma multiforme

    Microsoft Academic Search

    Norbert Galldiks; Roland Ullrich; Michael Schroeter; Gereon R. Fink; Lutz W. Kracht

    2010-01-01

    Purpose  We investigated the relationship between three-dimensional volumetric data of the metabolically active tumour volume assessed\\u000a using [11C]-methionine positron emission tomography (MET-PET) and the area of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA)\\u000a enhancement assessed using magnetic resonance imaging (MRI) in patients with recurrent glioblastoma (GBM).\\u000a \\u000a \\u000a \\u000a \\u000a Material and methods  MET-PET and contrast-enhanced MRI with Gd-DTPA were performed in 12 uniformly pretreated patients with recurrent GBM. To

  2. Ferumoxytol Enhanced resting state fMRI and Relative Cerebral Blood Volume mapping in Normal Human Brain

    PubMed Central

    D’Arceuil, Helen; Coimbra, Alexandre; Triano, Pamela; Dougherty, Margaret; Melo, Julie; Moseley, Michael; Glover, Gary; Lansberg, Maarten; Blankenberg, Francis

    2013-01-01

    The brain demonstrates spontaneous low-frequency (< 0.1 Hz) cerebral blood flow (CBF) fluctuations, measurable by resting-state functional MRI (rs-fMRI). Ultra small superparamagnetic iron oxide particles have been shown to enhance task-based fMRI signals (cerebral blood volume fMRI or CBV-fMRI), compared to the BOLD effect, by a factor of ? 2.5 at 3T in primates and humans. We evaluated the use of ferumoxytol for steady state,resting state FMRI (CBV-rs-fMRI) and relative cerebral blood volume (rCBV) mapping, at 3 Tesla, in healthy volunteers. All standard resting state networks (RSNs) were identified in all subjects.On average the RSN Z-statistics(Melodic independent components)and volumes of the Visual and default mode (DMN)networks were comparable rCBV values were averaged forthe visual (Vis) and DMN networks and correlated with the corresponding DMN and Visual network Z statistics. There was a negative correlation between the rCBV and the Z-statisticsforthe DMN, for both BOLD and CBVrs-fMRI contrast (R2= 0.63, 0.76).A similar correlation was not found for the visual network. Short repetition time rs-fMRI data were Fourier transformed to evaluate the effect of ferumoxytol on cardiac and respiratory fluctuations in the brain rs-BOLD, CBV signals. Cardiac and respiratory fluctuations decreased to baseline within large vessels post ferumoxytol.Robust rs-fMRI and CBV mapping is possible in normal human brain. PMID:23831413

  3. Simultaneous molecular imaging of redox reactions monitored by Overhauser-enhanced MRI with 14N- and 15N-labeled nitroxyl radicals

    Microsoft Academic Search

    Hideo Utsumi; Ken-Ichi Yamada; Kazuhiro Ichikawa; Kiyoshi Sakai; Yuichi Kinoshita; Shingo Matsumoto; Mika Nagai

    2006-01-01

    MRI has provided significant clinical utility in the diagnosis of diseases and will become a powerful tool to assess phenotypic changes in genetically engineered animals. Overhauser enhanced MRI (OMRI), which is a double resonance technique, creates images of free radical distributions in small animals by enhancing the water proton signal intensity by means of the Overhauser effect. Several studies have

  4. Assessment of vessel permeability by combining dynamic contrast-enhanced and arterial spin labeling MRI.

    PubMed

    Liu, Ho-Ling; Chang, Ting-Ting; Yan, Feng-Xian; Li, Cheng-He; Lin, Yu-Shi; Wong, Alex M

    2015-06-01

    The forward volumetric transfer constant (K(trans)), a physiological parameter extracted from dynamic contrast-enhanced (DCE) MRI, is weighted by vessel permeability and tissue blood flow. The permeability?×?surface area product per unit mass of tissue (PS) in brain tumors was estimated in this study by combining the blood flow obtained through pseudo-continuous arterial spin labeling (PCASL) and K(trans) obtained through DCE MRI. An analytical analysis and a numerical simulation were conducted to understand how errors in the flow and K(trans) estimates would propagate to the resulting PS. Fourteen pediatric patients with brain tumors were scanned on a clinical 3-T MRI scanner. PCASL perfusion imaging was performed using a three-dimensional (3D) fast-spin-echo readout module to determine blood flow. DCE imaging was performed using a 3D spoiled gradient-echo sequence, and the K(trans) map was obtained with the extended Tofts model. The numerical analysis demonstrated that the uncertainty of PS was predominantly dependent on that of K(trans) and was relatively insensitive to the flow. The average PS values of the whole tumors ranged from 0.006 to 0.217?min(-1), with a mean of 0.050?min(-1) among the patients. The mean K(trans) value was 18% lower than the PS value, with a maximum discrepancy of 25%. When the parametric maps were compared on a voxel-by-voxel basis, the discrepancies between PS and K(trans) appeared to be heterogeneous within the tumors. The PS values could be more than two-fold higher than the K(trans) values for voxels with high K(trans) levels. This study proposes a method that is easy to implement in clinical practice and has the potential to improve the quantification of the microvascular properties of brain tumors. PMID:25880892

  5. Computerized breast lesions detection using kinetic and morphologic analysis for dynamic contrast-enhanced MRI.

    PubMed

    Chang, Yeun-Chung; Huang, Yan-Hao; Huang, Chiun-Sheng; Chen, Jeon-Hor; Chang, Ruey-Feng

    2014-06-01

    To facilitate rapid and accurate assessment, this study proposed a novel fully automatic method to detect and identify focal tumor breast lesions using both kinetic and morphologic features from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). After motion registration of all phases of the DCE-MRI study, three automatically generated lines were used to segment the whole breast region of each slice. The kinetic features extracted from the pixel-based time-signal intensity curve (TIC) by a two-stage detection algorithm was first used, and then three-dimensional (3-D) morphologic characteristics of the detected regions were applied to differentiate between tumor and non-tumor regions. In this study, 95 biopsy-confirmed lesions (28 benign and 67 malignant lesions) in 54 women were used to evaluate the detection efficacy of the proposed system. The detection performance was analyzed using the free-response operating characteristics (FROC) curve and detection rate. The proposed computer-aided detection (CADe) system had a detection rate of 92.63% (88/95) of all tumor lesions, with 6.15 false positives per case. Based on the results, kinetic features extracted by TIC can be used to detect tumor lesions and 3-D morphology can effectively reduce the false positives. PMID:24582545

  6. 2014 Spring : Highly Distinguished Honors Highly Distinguished

    E-print Network

    Kasman, Alex

    Distinguished Allen Meagan Lynn Highly Distinguished Allen Nicholas Parker Highly Distinguished Allen Sarah Ena Christina Marie Highly Distinguished Barrett Nolan Hunter Highly Distinguished Barroso Parks Jose Highly

  7. 2009 Spring : Highly Distinguished Honors Highly Distinguished

    E-print Network

    Kasman, Alex

    Christina Highly Distinguished Bailey Christian Robert Highly Distinguished Baldwin Chelsey Kayla Highly Highly Distinguished Bridges Jason Edward Highly Distinguished Briner Chandler Marie Highly Distinguished

  8. Infarction of Uterine Fibroids After Embolization: Relationship Between Postprocedural Enhanced MRI Findings and Long-Term Clinical Outcomes

    SciTech Connect

    Katsumori, Tetsuya, E-mail: katsumo@eurus.dti.ne.jp; Kasahara, Toshiyuki; Kin, Yoko; Nozaki, Taiki [Saiseikai Shiga Hospital, Department of Radiology (Japan)

    2008-01-15

    Purpose. To retrospectively evaluate the relationship between the degree of infarction of uterine fibroids on enhanced MRI after embolization and long-term clinical outcomes. Methods. During 92 months, 290 consecutive patients with symptomatic uterine fibroids were treated with embolization; 221 who underwent enhanced MRI before embolization and 1 week after embolization were included in this study. The infarction rates of all fibroid tissue were assessed using enhanced MRI after embolization. Patients were divided into three groups according to the infarction rates: group A (100% infarction, n 142), group B (90-99% infarction, n = 74), group C (<90% infarction, n = 5). The cumulative rates of clinical outcomes were compared among groups using the Kaplan-Meier limited method. Results. Group A had a significantly higher rate of symptom control than groups B and C. The cumulative rates of symptom control at 5 years were 93%, 71%, and 60% in groups A, B, and C, respectively. Group A had a significantly lower rate of gynecologic intervention after embolization than groups B and C. The cumulative rates of additional gynecologic intervention at 5 years were 3%, 15%, and 20% in groups A, B, and C, respectively. Conclusions. The degree of infarction of uterine fibroids after embolization on enhanced MRI was related to long-term clinical outcomes. Complete infarction of all fibroid tissue can induce a higher rate of symptom control, with a lower rate of additional gynecologic intervention in the long term compared with incomplete infarction of fibroid tissue.

  9. Mathematical models of visual category learning enhance fMRI data analysis Emi M Nomura (e-nomura@northwestern.edu)

    E-print Network

    Maddox, W. Todd

    Mathematical models of visual category learning enhance fMRI data analysis Emi M Nomura (e category structure. The application of mathematical models of category learning to this behavioral data groups so as to encourage one type of strategy over another. Mathematical models of learning were fit

  10. 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

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

    PubMed

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

    2012-03-01

    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

  12. 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 ? rate constant was greater than the ? 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

  13. Renal and systemic pH imaging by contrast-enhanced MRI.

    PubMed

    Raghunand, Natarajan; Howison, Christine; Sherry, A Dean; Zhang, Shanrong; Gillies, Robert J

    2003-02-01

    Perturbations of renal and systemic pH accompany diseases of the kidney, such as renal tubular acidosis, and the ability to image tissue pH would be helpful to assess the extent and severity of such conditions. A dual-contrast-agent strategy using two gadolinium agents, the pH-insensitive GdDOTP(5-) and the pH-sensitive GdDOTA-4AmP(5-), has been developed to generate pH maps by MRI. The renal pharmacokinetics of the structurally dissimilar pH-insensitive contrast agents GdDTPA(2-) and GdDOTP(5-) were found to be similar. On that basis, and on the basis of similarity of structure and charge, the renal pharmacokinetics of GdDOTP(5-) and GdDOTA-4AmP(5-) were assumed to be identical. Dynamic T(1)-weighted images of mice were acquired for 1 hr each following boluses of GdDOTP(5-) and GdDOTA-4AmP(5-). The time-varying apparent concentration of GdDOTP(5-) and the time-varying enhancement in longitudinal relaxation rate following GdDOTA-4AmP(5-) were calculated for each pixel and used to compute pH images of the kidneys and surrounding tissues. MRI pH maps of control mice show acidic regions corresponding to the renal papilla, calyx, and ureter. Pretreatment of mice with the carbonic anhydrase inhibitor acetazolamide resulted in systemic metabolic acidosis and accompanying urine alkalinization that was readily detected by this dual-contrast-agent approach. PMID:12541244

  14. Intravascular contrast agent-enhanced MRI measuring contrast clearance and tumor blood volume and the effects of vascular modifiers in an experimental tumor

    SciTech Connect

    Bentzen, Lise [Experimental Clinical Oncology, Arhus University Hospital, Arhus (Denmark)]. E-mail: lise@oncology.dk; Vestergaard-Poulsen, Peter [Neuroradiology Research Unit, Arhus University Hospital, Arhus (Denmark); Nielsen, Thomas [Experimental Clinical Oncology, Arhus University Hospital, Arhus (Denmark); Neuroradiology Research Unit, Arhus University Hospital, Arhus (Denmark); Overgaard, Jens [Experimental Clinical Oncology, Arhus University Hospital, Arhus (Denmark); Bjornerud, Atle [Department of Radiology, Rikshospitalet, Oslo (Norway); Briley-Saebo, Karen [Amersham Health, Oslo (Norway); Horsman, Michael R. [Experimental Clinical Oncology, Arhus University Hospital, Arhus (Denmark); Ostergaard, Leif [Neuroradiology Research Unit, Arhus University Hospital, Arhus (Denmark)

    2005-03-15

    Purpose: To examine the feasibility of using the MRI blood pool agent NC100150 for evaluation of tumor blood volume (TBV) estimates by both dynamic contrast-enhanced MRI (DCE-MRI) and susceptibility contrast MRI assays in an experimental tumor. Contrast agent clearance (K{sup trans}; depends on perfusion and permeability) from the DCE-MRI time curves was estimated, and changes in TBV and K{sup trans} were measured after administration of two drugs that reduce perfusion by different mechanisms. Methods and materials: The DCE-MRI experiments were simulated with expected physiologic values for the C3H mouse mammary carcinoma. The C3H tumor was examined by DCE-MRI and susceptibility contrast MRI with NC100150 (NC100150 Injection, Clariscan; Amersham Health, Oslo, Norway) after treatment with either hydralazine or combretastatin (Oxigene, Boston, MA). Results: Simulations showed that reliable estimates of changes in TBV and K{sup trans} could be performed with DCE-MRI. Hydralazine was shown to reduce TBV as measured by both assays and to reduce K{sup trans}. Dynamic contrast-enhanced MRI also suggested that TBV and K{sup trans} were reduced in combretastatin-treated tumors, and the TBV reduction was confirmed by susceptibility contrast MRI. Data suggested the drug to affect mainly the total TBV, whereas microvessels as such seemed less altered. Conclusion: The study supports the use of the combined DCE-MRI and susceptibility contrast MRI assay with a blood pool agent in characterizing tumors and their response to treatment.

  15. Novel Platform for MRI-Guided Convection-Enhanced Delivery of Therapeutics: Preclinical Validation in Nonhuman Primate Brain

    Microsoft Academic Search

    R. Mark Richardson; Adrian P. Kells; Alastair J. Martin; Paul S. Larson; Philip A. Starr; Peter G. Piferi; Geoffrey Bates; Lisa Tansey; Kathryn H. Rosenbluth; John R. Bringas; Mitchel S. Berger; Krystof S. Bankiewicz

    2011-01-01

    Background\\/Aims: A skull-mounted aiming device and integrated software platform has been developed for MRI-guided neurological interventions. In anticipation of upcoming gene therapy clinical trials, we adapted this device for real-time convection-enhanced delivery of therapeutics via a custom-designed infusion cannula. The targeting accuracy of this delivery system and the performance of the infusion cannula were validated in nonhuman primates. Methods: Infusions

  16. Diagnostic per-patient accuracy of an abbreviated hepatobiliary phase gadoxetic acid-enhanced MRI for hepatocellular carcinoma surveillance.

    PubMed

    Marks, Robert M; Ryan, Andrew; Heba, Elhamy R; Tang, An; Wolfson, Tanya J; Gamst, Anthony C; Sirlin, Claude B; Bashir, Mustafa R

    2015-03-01

    OBJECTIVE. The purpose of this study is to evaluate the per-patient diagnostic performance of an abbreviated gadoxetic acid-enhanced MRI protocol for hepatocellular carcinoma (HCC) surveillance. MATERIALS AND METHODS. A retrospective review identified 298 consecutive patients at risk for HCC enrolled in a gadoxetic acid-enhanced MRI-based HCC surveillance program. For each patient, the first gadoxetic acid-enhanced MRI was analyzed. To simulate an abbreviated protocol, two readers independently read two image sets per patient: set 1 consisted of T1-weighted 20-minute hepatobiliary phase and T2-weighted single-shot fast spin-echo (SSFSE) images; set 2 included diffusion-weighted imaging (DWI) and images from set 1. Image sets were scored as positive or negative according to the presence of at least one nodule 10 mm or larger that met the predetermined criteria. Agreement was assessed using Cohen kappa statistics. A composite reference standard was used to determine the diagnostic performance of each image set for each reader. RESULTS. Interreader agreement was substantial for both image sets (? = 0.72 for both) and intrareader agreement was excellent (? = 0.97-0.99). Reader performance for image set 1 was sensitivity of 85.7% for reader A and 79.6% for reader B, specificity of 91.2% for reader A and 95.2% for reader B, and negative predictive value of 97.0% for reader A and 96.0% for reader B. Reader performance for image set 2 was nearly identical, with only one of 298 examinations scored differently on image set 2 compared with set 1. CONCLUSION. An abbreviated MRI protocol consisting of T2-weighted SSFSE and gadoxetic acid-enhanced hepatobiliary phase has high negative predictive value and may be an acceptable method for HCC surveillance. The inclusion of a DWI sequence did not significantly alter the diagnostic performance of the abbreviated protocol. PMID:25714281

  17. System identification theory in pharmacokinetic modeling of dynamic contrast-enhanced MRI: influence of contrast injection.

    PubMed

    Aerts, H J W L; van Riel, N A W; Backes, W H

    2008-05-01

    Optimization of experimental settings of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), like the contrast administration protocol, is of great importance for reliable quantification of the microcirculatory properties, such as the volume transfer-constant K(trans). Using system identification theory and computer simulations, the confounding effects of volume, rate and multiplicity of a contrast injection on the reliability of K(trans) estimation was assessed. A new tracer-distribution model (TDM), based on in vivo data from rectal cancer patients, served to describe the relationship between the contrast agent injection and the blood time-course. A pharmacokinetic model (PKM) was used to describe the relation between the blood and tumor tissue time-courses. By means of TDM and PKM in series, the tissue-transfer function of the PKM was analyzed. As both the TDM and PKM represented low-frequency-pass filters, the energy-density at low frequencies of the blood and tissue time-courses was larger than at high frequencies. The simulations, based on measurements in humans, predict that the K(trans) is most reliable with a high injection volume administered in a single injection, where high rates only modestly improve K(trans). PMID:18429040

  18. In Vivo Detection of Excitotoxicity by Manganese-Enhanced MRI: Comparison with Physiological Stimulation

    PubMed Central

    Gobbo, Oliviero L.; Petit, Fanny; Gurden, Hirac; Dhenain, Marc

    2013-01-01

    Manganese-enhanced MRI (MEMRI) is a powerful technique for the in vivo monitoring of brain function in animals. Manganese enters into cells through calcium channels, i.e., voltage-gated calcium channels and activated glutamate receptors (e.g., N-methyl-D-aspartate receptors). N-methyl-D-aspartate receptors are activated both in normal physiological and pathophysiological conditions. Consistent with these mechanisms, we showed that in the olfactory bulb, the MEMRI signal strongly increases when excitotoxic mechanisms are induced by an administration of a N-methyl-D-aspartate receptor agonist, quinolinate. We found that the intensity of the MEMRI signal in excitotoxic conditions is similar to the odor-evoked signal in normal physiological conditions. Finally, we showed that the dynamics of the MEMRI signal are determined by the early phase of manganese in the olfactory bulb. Overall, these data show that, in addition to physiological studies, MEMRI can be used as an in vivo method to follow-up the dynamics of excitotoxic events. Magn Reson Med 68:234–240, 2012. PMID:22127903

  19. Dynamic contrast-enhanced MRI using macromolecular contrast media for monitoring the response to isolated limb perfusion in experimental soft-tissue sarcomas

    Microsoft Academic Search

    A. Preda; P. A. Wielopolski; T. L. M. ten Hagen; M. van Vliet; J. F. Veenland; G. Ambagtsheer; S. T. van Tiel; M. W. Vogel; A. M. M. Eggermont; G. P. Krestin; C. F. van Dijke

    2004-01-01

    The objective of this study was to evaluate the potential of dynamic contrast-enhanced MRI for quantitative characterization of tumor microvessels and to assess the microvascular changes in response to isolated limb perfusion with TNF- and melphalan. Dynamic contrast-enhanced MRI was performed in an experimental cancer model, using a macromolecular contrast medium, albumin-(Gd-DTPA)45. Small fragments of BN 175, a soft-tissue sarcoma,

  20. The Incremental Value of Contrast-Enhanced MRI in the Detection of Biopsy-Proven Local Recurrence of Prostate Cancer After Radical Prostatectomy: Effect of Reader Experience

    PubMed Central

    Wassberg, Cecilia; Akin, Oguz; Vargas, Hebert Alberto; Shukla-Dave, Amita; Zhang, Jingbo; Hricak, Hedvig

    2012-01-01

    OBJECTIVE The purpose of this study is to retrospectively assess the incremental value of contrast-enhanced MRI (CE-MRI) to T2-weighted MRI in the detection of postsurgical local recurrence of prostate cancer by readers of different experience levels, using biopsy as the reference standard. MATERIALS AND METHODS Fifty-two men with biochemical recurrence after prostatectomy underwent 1.5-T endorectal MRI with multiphase contrast-enhanced imaging and had biopsy within 3 months of MRI. Two radiologists (reader 1 had 1 year and reader 2 had 6 years of experience) independently reviewed each MRI study and classified the likelihood of recurrent cancer on a 5-point scale. Areas under receiver operating characteristic curves (Az) were calculated to assess readers’ diagnostic performance with T2-weighted MRI alone and combined with CE-MRI. Interobserver agreement was assessed using Cohen kappa statistics. RESULTS Thirty-three patients (63%) had biopsy-proven local recurrence of prostate cancer. With the addition of CE-MRI to T2-weighted imaging, the Az for cancer detection increased significantly for reader 1 (0.77 vs 0.85; p = 0.0435) but not for reader 2 (0.86 vs 0.88; p = 0.7294). The use of CE-MRI improved interobserver agreement from fair (? = 0.39) to moderate (? = 0.58). CONCLUSION CE-MRI increased interobserver agreement and offered incremental value to T2-weighted MRI in the detection of locally recurrent prostate cancer for the relatively inexperienced reader. PMID:22826397

  1. Multiple hepatorenal angiomyolipomas: Diagnosis with fat suppression, gadolinium-enhanced MRI

    Microsoft Academic Search

    L. D. Hooper; P. J. Mergo; P. R. Ros

    1994-01-01

    Hepatic angiomyolipoma is a rare tumor which may occur as a solitary mass or as an associated finding with tuberous sclerosis. While computed tomography allows identification of the fat component of the lesion, magnetic resonance imaging (MRI) can provide similar information, as well as multiplanar visualization and further characterization of the vascular component of the lesion. MRI utilizing fat suppression

  2. Spinal epidural abscess with gadolinium-enhanced MRI: serial follow-up studies and clinical correlations

    Microsoft Academic Search

    N. Sadato; Y. Numaguchi; D. Rigamonti; T. Kodama; E. Nussbaum; S. Sato; M. Rothman

    1994-01-01

    We reviewed serial MRI with and without gadolinium-DTPA in eight patients with spinal epidural abscess and correlated the findings and the clinical manifestations. In four patients, diffuse abscesses spanned four vertebral bodies or more; the others had focal abscesses associated with osteomyelitis and\\/or diskitis. In three of the four patients with diffuse abscesses, MRI (NCMRI) showed diffuse encasement of the

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

    PubMed

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

    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

  4. 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

  5. Prediction of Prostate Cancer Extracapsular Extension with High Spatial Resolution Dynamic Contrast-Enhanced 3 Tesla MRI

    PubMed Central

    Bloch, B. Nicolas; Genega, Elizabeth M.; Costa, Daniel N.; Pedrosa, Ivan; Smith, Martin P.; Kressel, Herbert Y.; Ngo, Long; Sanda, Martin G.; DeWolf, William C.; Rofsky, Neil M.

    2013-01-01

    Objectives To assess the value of dynamic contrast-enhanced (DCE) combined with T2-weighted (T2W) endorectal coil (ERC) magnetic resonance imaging (MRI) at 3 T (3T) for determining extracapsular extension (ECE) of prostate cancer. Methods In this IRB-approved study, ERC 3T MRI of the prostate was performed in 108 patients prior to radical prostatectomy. T2W fast spin-echo and DCE 3D gradient echo images were acquired. The interpretations of readers with varied experience were analyzed. MRI-based staging results were compared with radical prostatectomy histology. Descriptive statistics were generated for prediction of ECE and staging accuracies were determined by the area under the receiver-operating-characteristic curve. Results The overall sensitivity, specificity, positive predictive value, and negative predictive value for ECE were 75%, 92%, 79% and 91%, respectively. Diagnostic accuracy for staging was 86%, 80% and 91% for all readers, experienced and less experienced readers, respectively. Conclusions ERC 3T MRI of the prostate combining DCE and T2W imaging is an accurate pretheurapeutic staging tool for assessment of ECE in clinical practice across varying levels of reader experience. PMID:22661019

  6. 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.

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

    NASA Astrophysics Data System (ADS)

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

    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

  8. Assessment of Clinical Signs of Liver Cirrhosis Using T1 Mapping on Gd-EOB-DTPA-Enhanced 3T MRI

    PubMed Central

    Haimerl, Michael; Verloh, Niklas; Zeman, Florian; Fellner, Claudia; Müller-Wille, René; Schreyer, Andreas G.; Stroszczynski, Christian; Wiggermann, Philipp

    2013-01-01

    Objectives To assess the differences between normal and cirrhotic livers by means of T1 mapping of liver parenchyma on gadoxetic acid (Gd-EOB-DTPA)-enhanced 3 Tesla (3T) MR imaging (MRI). Methods 162 patients with normal (n = 96) and cirrhotic livers (n = 66; Child-Pugh class A, n = 30; B, n = 28; C, n = 8) underwent Gd-EOB-DTPA-enhanced 3T MRI. To obtain T1 maps, two TurboFLASH sequences (TI = 400 ms and 1000 ms) before and 20 min after Gd-EOB-DTPA administration were acquired. T1 relaxation times of the liver and the reduction rate between pre- and post-contrast enhancement images were measured. Results The T1 relaxation times for Gd-EOB-DTPA-enhanced MRI showed significant differences between patients with normal liver function and patients with Child-Pugh class A, B, and C (p < 0.001). The T1 relaxation times showed a constant significant increase from Child-Pugh class A up to class C (Child-Pugh class A, 335 ms ± 80 ms; B, 431 ms ± 75 ms; C, 557 ms ± 99 ms; Child-Pugh A to B, p < 0.001; Child-Pugh A to C, p < 0.001; Child-Pugh B to C, p < 0.001) and a constant decrease of the reduction rate of T1 relaxation times (Child-Pugh class A, 57.1% ± 8.8%; B, 44.3% ± 10.2%, C, 29.9% ± 6.9%; Child-Pugh A to B, p < 0.001; Child-Pugh A to C,p < 0.001; Child-Pugh B to C, p < 0.001). Conclusion Gd-EOB-DTPA-enhanced T1 mapping of the liver parenchyma may present a useful method for determining severity of liver cirrhosis. PMID:24392025

  9. Contrast-enhanced MRI with new biodegradable macromolecular Gd(III) complexes in tumor-bearing mice.

    PubMed

    Zong, Yuda; Wang, Xinghe; Goodrich, K Craig; Mohs, Aaron M; Parker, Dennis L; Lu, Zheng-Rong

    2005-04-01

    The structures of polydisulfide-based biodegradable macromolecular Gd(III) complexes were modified to improve their in vivo retention time and MRI contrast enhancement. Steric hindrance was introduced around the disulfide bonds to control their access to free thiols in order to alter the degradation rate of the copolymers. Two new macromolecular agents, (Gd-DTPA)-cystine copolymers (GDCP) and (Gd-DTPA)-cystine diethyl ester copolymers (GDCEP), were prepared. Both agents were readily degraded in vitro and in vivo by the disulfide-thiol exchange reaction, but at a slow rate. The introduction of COOH and COOEt groups slowed down the degradation of the copolymers in the incubation with 15 microM cysteine. Metabolic degradation products were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry in the urine samples from rats injected with the agents. The T(1) relaxivity (r(1)) was 5.43 mM(-1)s(-1) for GDCP, and 5.86 mM(-1)s(-1) for GDCEP, respectively, at 3T. MRI contrast enhancement of both agents was studied in nude mice bearing MDA-BM-231 human breast carcinoma xenografts, on a Siemens Trio 3T scanner. The modified agents resulted in more significant contrast enhancement in the blood pool and tumor periphery than (Gd-DTPA)-cystamine copolymers (GDCC) and a low-molecular-weight control agent, Gd-(DTPA-BMA), at a dose of 0.1 mmol-Gd/kg. The results demonstrate that the structural modification of the biodegradable macromolecular Gd(III) complexes resulted in a relatively slow degradation of the macromolecules and significantly improved in vivo contrast enhancement. The modified agents show promise for use in investigations of blood pool and cancer by contrast-enhanced (CE) MRI. PMID:15799038

  10. 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 120 minutes and 3D gradient-echo (3D GRE) dual flip-angle sequences were performed at 14 time points covering 130 minutes after the administration of 0.2 mmol/kg of Gd-diethylenetriamine pentaacetic acid ion (Gd-DTPA)2-, i.e., 0.4 mL 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 60 minutes after bolus injection in the TMJ disc. The 3D GRE dual flip-angle sequences confirmed these results and show plateau of T1 after 60 minutes. 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 120 minutes. PMID:25131629

  11. Noninvasive assessment of tumor microenvironment using dynamic contrast enhanced MRI and 18F- fluoromisonidazole PET imaging in neck nodal metastases

    PubMed Central

    Jansen, Jacobus F. A.; Schöder, Heiko; Lee, Nancy Y.; Wang, Ya; Pfister, David. G.; Fury, Matthew G.; Stambuk, Hilda. E.; Humm, John L.; Koutcher, Jason A.; Shukla-Dave, Amita

    2009-01-01

    Purpose Pretreatment multimodality imaging can provide useful anatomical and functional data about tumors, including perfusion and possibly hypoxia status. The purpose of our study was to assess non-invasively the tumor microenvironment of neck nodal metastases in patients with head and neck (HN) cancer by investigating the relationship between tumor perfusion measured using Dynamic Contrast Enhanced MRI (DCE-MRI) and hypoxia measured by 18F-fluoromisonidazole (18F-FMISO) PET. Methods and Materials Thirteen newly diagnosed HN cancer patients with metastatic neck nodes underwent DCE-MRI and 18F-FMISO PET imaging prior to chemotherapy and radiation therapy. The matched regions of interests from both modalities were analyzed. To examine the correlations between DCE-MRI parameters and standard uptake value (SUV) measurements from 18F-FMISO PET, the non-parametric Spearman correlation coefficient was calculated. Furthermore, DCE-MRI parameters were compared between nodes with 18F-FMISO uptake and nodes with no 18F-FMISO uptake using Mann-Whitney U tests. Results For the 13 patients, a total of 18 nodes were analyzed. The nodal size strongly correlated with the 18F-FMISO SUV (?=0.74, p<0.001). There was a strong negative correlation between the median kep (?=?0.58, p=0.042) and the 18F-FMISO SUV. Hypoxic nodes (moderate to severe 18F-FMISO uptake) had significantly lower median Ktrans (p=0.049) and median kep (p=0.027) values than did non-hypoxic nodes (no 18F-FMISO uptake). Conclusion This initial evaluation of the preliminary results support the hypothesis that in metastatic neck lymph nodes, hypoxic nodes are poorly perfused (i.e., have significantly lower kep and Ktrans values) compared to non-hypoxic nodes. PMID:19906496

  12. Parameters of Dynamic Contrast-Enhanced MRI as Imaging Markers for Angiogenesis and Proliferation in Human Breast Cancer

    PubMed Central

    Li, Lin; Wang, Kai; Sun, Xilin; Wang, Kezheng; Sun, Yingying; Zhang, Guangfeng; Shen, Baozhong

    2015-01-01

    Background Breast cancer is the most common malignancy and the leading cause of cancer death in women worldwide; however, early diagnosis has been difficult due to its complex pathological structure. This study evaluated the value of morphological examination in conjunction with dynamic contrast-enhanced MRI (DCE-MRI) for more precise diagnosis of breast cancer, as well as their correlation with angiogenesis and proliferation biomarkers. Material/Methods DCE-MRI parameters (including Ktrans: volume transfer coefficient reflecting vascular permeability, Kep: flux rate constant, Ve: extracellular volume ratio reflecting vascular permeability, and ADC: apparent diffusion coefficient) were obtained from 124 patients with breast cancer (124 lesions). Microvessel density (MVD) was evaluated by the immunohistochemical analysis of tumor vessels for CD31 and CD105 expression. The proliferation was assessed by analyzing Ki67. Results Ktrans values were in the order of: malignant lesions > benign lesions > normal glands. Similar results were observed for Kep. The opposite changes were seen with Ve. Ktrans and Kep values were significantly higher in invasive ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS) than in mammary ductal dysplasia (MDD; ANOVA followed by Dunnett’s test). In sharp contrast, ADC values were lower in IDC and DCIS than in MDD, and Ve was not significantly different among the three groups. The data from MIP (maximum intensity projection) showed that benign breast lesions had no or only one blood vessel, whereas malignant lesions had two or more blood vessels. In addition, expression of CD105 and Ki67, the commonly recognized markers for angiogenesis and proliferation, respectively, were closely correlated with MRI parameters as revealed by Pearson analysis. Conclusions Determination of Ktrans, Kep and ADC values permits estimation of tumor angiogenesis and proliferation in breast cancer and DCE-MRI parameters can be used as imaging biomarkers to predict patient prognosis and the biologic aggressiveness of the tumor. PMID:25640082

  13. Original Research Manganese-Enhanced MRI in a Rat Model of

    E-print Network

    Friedman, Nir

    of manganese chlo- ride into the entopeduncular (EP), substantia nigra (SN), and the Habenula nuclei-hydroxydopamine, BG basal ganglia, SN substantia nigra, SNc substantia nigra pars compacta, MRI magnetic resonance

  14. Metal-substituted protein MRI contrast agents engineered for enhanced relaxivity and ligand sensitivity

    E-print Network

    Lelyveld, Victor S.

    Engineered metalloproteins constitute a flexible new class of analyte-sensitive molecular imaging agents detectable by magnetic resonance imaging (MRI), but their contrast effects are generally weaker than synthetic agents. ...

  15. Evaluating regional blood spinal cord barrier dysfunction following spinal cord injury using longitudinal dynamic contrast-enhanced MRI

    PubMed Central

    2009-01-01

    Background In vivo preclinical imaging of spinal cord injury (SCI) in rodent models provides clinically relevant information in translational research. This paper uses multimodal magnetic resonance imaging (MRI) to investigate neurovascular pathology and changes in blood spinal cord barrier (BSCB) permeability following SCI in a mouse model of SCI. Methods C57BL/6 female mice (n = 5) were subjected to contusive injury at the thoracic T11 level and scanned on post injury days 1 and 3 using anatomical, dynamic contrast-enhanced (DCE-MRI) and diffusion tensor imaging (DTI). The injured cords were evaluated postmortem with histopathological stains specific to neurovascular changes. A computational model was implemented to map local changes in barrier function from the contrast enhancement. The area and volume of spinal cord tissue with dysfunctional barrier were determined using semi-automatic segmentation. Results Quantitative maps derived from the acquired DCE-MRI data depicted the degree of BSCB permeability variations in injured spinal cords. At the injury sites, the damaged barriers occupied about 70% of the total cross section and 48% of the total volume on day 1, but the corresponding measurements were reduced to 55% and 25%, respectively on day 3. These changes implied spatio-temporal remodeling of microvasculature and its architecture in injured SC. Diffusion computations included longitudinal and transverse diffusivities and fractional anisotropy index. Comparison of permeability and diffusion measurements indicated regions of injured cords with dysfunctional barriers had structural changes in the form of greater axonal loss and demyelination, as supported by histopathologic assessments. Conclusion The results from this study collectively demonstrated the feasibility of quantitatively mapping regional BSCB dysfunction in injured cord in mouse and obtaining complementary information about its structural integrity using in vivo DCE-MRI and DTI protocols. This capability is expected to play an important role in characterizing the neurovascular changes and reorganization following SCI in longitudinal preclinical experiments, but with potential clinical implications. PMID:19519898

  16. Detection of local recurrent prostate cancer after radical prostatectomy in terms of salvage radiotherapy using dynamic contrast enhanced-MRI without endorectal coil

    PubMed Central

    2012-01-01

    Purpose To evaluate the value of dynamic contrast enhanced Magnetic Resonance Imaging (DCE-MRI) without endorectal coil (EC) in the detection of local recurrent prostate cancer (PC) after radical prostatectomy (RP). Material and methods Thirty-three patients with recurrent PC underwent DCE-MRI without EC before salvage radiotherapy (RT). At median 15 (mean 16±4.9, range 12–27) months after completion of RT all patients showed complete biochemical response. Additional follow up post RT DCE-MRI scans were available. Prostate specific antigen (PSA) levels at the time of imaging were correlated to the imaging findings. Results In 22/33 patients (67%) early contrast enhancing nodules were detected in the post-prostatectomy fossa on pre-RT DCE-MRI images. The average pre-RT PSA level of the 22 patients with positive pre-RT DCE-MRI findings was significantly higher (mean, 0.74±0.64 ng/mL) compared to the pre-RT PSA level of the 11 patients with negative pre-RT DCE-MRI (mean, 0.24±0.13 ng/mL) (p<0.001). All post-RT DCE-MRI images showed complete resolution of initial suspicious lesions. A pre-RT PSA cut-off value of ?0.54 ng/ml readily predicted a positive DCE-MRI finding. Conclusions This is the first study that shows that DCE-MRI without EC can detect local recurrent PC with an estimated accuracy of 83% at low PSA levels. All false negative DCE-MRI scans were detected using a PSA cut-off of ?0.54 ng/mL. PMID:23114282

  17. Validation of Contrast-Enhanced MRI to Monitor Regenerative Efficacy after Cell Therapy in a Porcine Model of Convalescent Myocardial Infarction

    PubMed Central

    Malliaras, Konstantinos; Smith, Rachel R.; Kanazawa, Hideaki; Yee, Kristine; Seinfeld, Jeffrey; Tseliou, Eleni; Dawkins, James F.; Kreke, Michelle; Cheng, Ke; Luthringer, Daniel; Ho, Chak-Sum; Blusztajn, Agnieszka; Valle, Ileana; Chowdhury, Supurna; Makkar, Raj R.; Dharmakumar, Rohan; Li, Debiao; Marbán, Linda; Marbán, Eduardo

    2014-01-01

    Background Magnetic Resonance Imaging (MRI) in the CADUCEUS trial revealed that cardiosphere-derived cells (CDCs) decrease scar size and increase viable myocardium post-myocardial infarction (MI), but MRI has not been validated as an index of regeneration after cell therapy. We tested the validity of contrast-enhanced MRI in quantifying scarred and viable myocardium after cell therapy in a porcine model of convalescent MI. Methods and Results Yucatan minipigs underwent induction of MI and 2-3 weeks later were randomized to receive intracoronary infusion of 12.5×106 mismatched allogeneic CDCs or vehicle. Allogeneic CDCs induced mild local mononuclear infiltration but no systemic immunogenicity. MRI revealed that allogeneic CDCs attenuated remodeling, improved global and regional function, decreased scar size and increased viable myocardium compared to placebo 2 months post-treatment. Extensive histological analysis validated quantitatively the MRI measurements of scar size, scar mass and viable mass. CDCs neither altered gadolinium contrast myocardial kinetics, nor induced changes in vascular density or architecture in viable and scarred myocardium. Histology demonstrated that CDCs lead to cardiomyocyte hyperplasia in the border zone, consistent with the observed stimulation of endogenous regenerative mechanisms (cardiomyocyte cycling, upregulation of endogenous progenitors, angiogenesis). Conclusions Contrast-enhanced MRI accurately measures scarred and viable myocardium after cell therapy in a porcine model of convalescent MI. MRI represents a useful tool for assessing dynamic changes in the infarct and monitoring regenerative efficacy. PMID:24061088

  18. 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. [Imaging Science and Biomedical Engineering, University of Manchester, Manchester (United Kingdom) and Cancer Research UK Department of Medical Oncology, Christie Hospital, Manchester (United Kingdom); Naish, Josephine H.; Parker, Geoff J.M. [Imaging Science and Biomedical Engineering, University of Manchester, Manchester (United Kingdom); Waterton, John C. [Imaging Science and Biomedical Engineering, University of Manchester, Manchester (United Kingdom); AstraZeneca, Cheshire (United Kingdom); Watson, Yvonne [Imaging Science and Biomedical Engineering, University of Manchester, Manchester (United Kingdom); Jayson, Gordon C. [Cancer Research UK Department of Medical Oncology, Christie Hospital, Manchester (United Kingdom); Buonaccorsi, Giovanni A.; Cheung, Sue; Buckley, David L.; McGrath, Deirdre M. [Imaging Science and Biomedical Engineering, University of Manchester, Manchester (United Kingdom); West, Catharine M.L. [Academic Department of Radiation Oncology, University of Manchester, Manchester (United Kingdom); Davidson, Susan E. [Department of Clinical Oncology, Christie Hospital, Manchester (United Kingdom); Roberts, Caleb; Mills, Samantha J. [Imaging Science and Biomedical Engineering, University of Manchester, Manchester (United Kingdom); Mitchell, Claire L.; Hope, Lynn; Ton, N. Chan [Cancer Research UK Department of Medical Oncology, Christie Hospital, Manchester (United Kingdom); Jackson, Alan [Imaging Science and Biomedical Engineering, University of Manchester, Manchester (United Kingdom)

    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.

  19. 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

  20. pH-Responsive Theranostic Polymer-Caged Nanobins (PCNs): Enhanced Cytotoxicity and T1 MRI Contrast by Her2-Targeting

    PubMed Central

    Hong, Bong Jin; Swindell, Elden P.; MacRenaris, Keith W.; Hankins, Patrick L.; Chipre, Anthony J.; Mastarone, Daniel J.; Ahn, Richard W.; Meade, Thomas J.; O’Halloran, Thomas V.

    2014-01-01

    A PCN theranostic platform comprises a doxorubicin (DXR)-loaded liposomal core and an acid-sensitive polymer shell that is functionalized with Herceptin and GdIII-based MRI contrast agents. In vitro testing reveals a 14-fold increase in DXR-based cytotoxicity versus a non-targeted analogue and an 120-fold improvement in cellular GdIII–uptake in comparison with clinically approved DOTA-GdIII, leading to significant T1 MRI contrast enhancement. PMID:24516291

  1. Chemotherapy response monitoring of colorectal liver metastases by dynamic Gd-DTPA-enhanced MRI perfusion parameters and 18F-FDG PET metabolic rate

    Microsoft Academic Search

    D. Vriens; H. W. M. van Laarhoven; J. J. A. van Asten; P.F.M. Krabbe; E. P. Visser; A. Heerschap; C. J. A. Punt; L.-F. de Geus-Oei; W. J. G. Oyen

    2009-01-01

    In this study, we examined the in vivo relationship between functional tumor vasculature, determined by dynamic contrast-enhanced (DCE-) MRI, and tumor metabolism, determined by dynamic (18)F-FDG PET, during cytotoxic treatment of patients with colorectal liver metastases. METHODS: Twenty-three patients underwent DCE-MRI (using gadolinium dimeglumine) and dynamic (18)F-FDG PET at baseline and after 3 treatment cycles, unless treatment was terminated because

  2. Perfusion characteristics of late radiation injury of parotid glands: quantitative evaluation with dynamic contrast-enhanced MRI

    Microsoft Academic Search

    Chun-Jung Juan; Cheng-Yu Chen; Yee-Min Jen; Hua-Shan Liu; Yi-Jui Liu; Chun-Jen Hsueh; Chao-Ying Wang; Yu-Ching Chou; Yao-Te Chai; Guo-Shu Huang; Hsiao-Wen Chung

    2009-01-01

    We aimed to quantitatively investigate the alteration of parotid perfusion after irradiation using dynamic contrast-enhanced\\u000a magnetic resonance imaging (DCE-MRI) based on a two-compartment tracer kinetic model. This study enrolled 19 patients (53.2?±?14.9 years)\\u000a treated by head and neck radiotherapy and 19 age-relevant and sex-matched subjects as a control group. Perfusion parameters\\u000a (K\\u000a \\u000a el\\u000a , k\\u000a 21 and A) of parotid glands

  3. 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

  4. Atrial Fibrosis Quantified Using Late Gadolinium Enhancement MRI is Associated With Sinus Node Dysfunction Requiring Pacemaker Implant

    PubMed Central

    Akoum, Nazem; Mcgann, Christopher; Vergara, Gaston; Badger, Troy; Ranjan, Ravi; Mahnkopf, Christian; Kholmovski, Eugene; Macleod, Rob; Marrouche, Nassir

    2015-01-01

    Introduction Sinus node dysfunction (SND) commonly manifests with atrial arrhythmias alternating with sinus pauses and sinus bradycardia. The underlying process is thought to be because of atrial fibrosis. We assessed the value of atrial fibrosis, quantified using Late Gadolinium Enhanced-MRI (LGE-MRI), in predicting significant SND requiring pacemaker implant. Methods Three hundred forty-four patients with atrial fibrillation (AF) presenting for catheter ablation underwent LGE-MRI. Left atrial (LA) fibrosis was quantified in all patients and right atrial (RA) fibrosis in 134 patients. All patients underwent catheter ablation with pulmonary vein isolation with posterior wall and septal debulking. Patients were followed prospectively for 329 ± 245 days. Ambulatory monitoring was instituted every 3 months. Symptomatic pauses and bradycardia were treated with pacemaker implantation per published guidelines. Results The average patient age was 65 ± 12 years. The average wall fibrosis was 16.7 ± 11.1% in the LA, and 5.3 ± 6.4% in the RA. RA fibrosis was correlated with LA fibrosis (R2 = 0.26; P < 0.01). Patients were divided into 4 stages of LA fibrosis (Utah I: <5%, Utah II: 5–20%, Utah III: 20–35%, Utah IV: >35%). Twenty-two patients (mean atrial fibrosis, 23.9%) required pacemaker implantation during follow-up. Univariate and multivariate analysis identified LA fibrosis stage (OR, 2.2) as a significant predictor for pacemaker implantation with an area under the curve of 0.704. Conclusions In patients with AF presenting for catheter ablation, LGE-MRI quantification of atrial fibrosis demonstrates preferential LA involvement. Significant atrial fibrosis is associated with clinically significant SND requiring pacemaker implantation. PMID:21806700

  5. University Senate Diversity Committee 2007-08 Report I. Distinguished Diversity Enhancement Awards: There were 10 applicants and 5

    E-print Network

    Jones, Michelle

    those protected by law (e.g., learning styles, economic status)? We plan to begin these activities Council Co-Chaired by Dr. Valerie Lee and Dr. Georgina Dodge reviewed the annual College Diversity Reports and completed an integrated report on College and Unit movement towards enhancing diversity across

  6. Enhanced false discovery rate using Gaussian mixture models for thresholding fMRI statistical maps.

    PubMed

    Pendse, Gautam; Borsook, David; Becerra, Lino

    2009-08-01

    A typical fMRI data analysis proceeds via the generalized linear model (GLM) with Gaussian noise using a model based on the experimental paradigm. This analysis ultimately results in the production of z-statistic images corresponding to the contrasts of interest. Thresholding such z-statistic images at uncorrected thresholds suitable for testing activation at a single voxel results in the problem of multiple comparisons. A number of methods which account for the problem of multiple comparisons have been proposed including Gaussian random field theory, mixture modeling and false discovery rate (FDR). The focus of this paper is on the development of a generalized version of FDR (GFDR) in an empirical Bayesian framework, specially adapted for fMRI thresholding, that is more robust to modeling violations as compared to traditional FDR. We show theoretically as well as by simulation that for real fMRI data various factors lead to a mixture of Gaussians (MOG) density for the "null" distribution. Artificial data was used to systematically study the bias of FDR and GFDR under varying intensity of modeling violations, signal to noise ratios and activation fractions for a range of q values. GFDR was able to handle modeling violations and produce good results when FDR failed. Real fMRI data was also used to confirm GFDR capabilities. Our results indicate that it is very important to account for the form and fraction of the "null" hypothesis adaptively from the data in order to obtain valid inference. PMID:19269334

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

    NASA Astrophysics Data System (ADS)

    Kratzke, Jonas; Schoch, Nicolai; Weis, Christian; Müller-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.

  8. 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(?-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

  9. 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

  10. In vivo high-resolution 3D overhauser-enhanced MRI in mice at 0.2?T.

    PubMed

    Massot, Philippe; Parzy, Elodie; Pourtau, Line; Mellet, Philippe; Madelin, Guillaume; Marque, Sylvain; Franconi, Jean-Michel; Thiaudiere, Eric

    2012-01-01

    Overhauser-enhanced MRI (OMRI) offers the potentiality of detecting low-concentrated species generated by specific biological processes. However molecular imaging applications of OMRI need significant improvement in spatial localization. Here it is shown that 3D-OMRI of a free radical injected in tumor-bearing mice can be performed at high anatomical resolution at a constant field. A 30 mm cavity operating at 5.43?GHz was inserted in a C-shaped magnet for proton MRI at 0.194 T. Nude mice with or without brain-implanted C6 rat glioma were positioned in the cavity and injected with TOPCA (1-oxyl-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrole-3-carboxylic acid). OMRI was performed in 3D within several minutes in the brain region without high overheating of the animals. Voxel size was 0.5?×?0.5?×?1?mm³ , providing good delineation of brain regions. Signal amplifications ranged from 2 in tumors to 10 in vessels several minutes after TOPCA injection. Time-course of signal enhancement could be measured by 2D OMRI at 15?s time intervals in a localized thin slice. The method opens the way for molecular imaging of biological activities able to generate OMRI-visible free radicals. PMID:22344879

  11. Enhanced MRI relaxivity of aquated Gd3+ ions by carboxyphenylated water-dispersed graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Gizzatov, Ayrat; Keshishian, Vazrik; Guven, Adem; Dimiev, Ayrat M.; Qu, Feifei; Muthupillai, Raja; Decuzzi, Paolo; Bryant, Robert G.; Tour, James M.; Wilson, Lon J.

    2014-02-01

    The present study demonstrates that highly water-dispersed graphene nanoribbons dispersed by carboxyphenylated substituents and conjugated to aquated Gd3+ ions can serve as a high-performance contrast agent (CA) for applications in T1- and T2-weighted magnetic resonance imaging (MRI) with relaxivity (r1,2) values outperforming currently-available clinical CAs by up to 16 times for r1 and 21 times for r2.The present study demonstrates that highly water-dispersed graphene nanoribbons dispersed by carboxyphenylated substituents and conjugated to aquated Gd3+ ions can serve as a high-performance contrast agent (CA) for applications in T1- and T2-weighted magnetic resonance imaging (MRI) with relaxivity (r1,2) values outperforming currently-available clinical CAs by up to 16 times for r1 and 21 times for r2. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr06026h

  12. Double contrast-enhanced MRI of viral hepatitis-induced cirrhosis: correlation of gross morphological signs with hepatic fibrosis.

    PubMed

    Yu, J S; Shim, J H; Chung, J J; Kim, J H; Kim, K W

    2010-03-01

    The purpose of this study was to evaluate the diagnostic ability of the expanded gallbladder fossa and right posterior hepatic notch signs for hepatic fibrosis determined by double contrast-enhanced MRI. For patients with chronic viral hepatitis B (n = 96) or hepatitis C (n = 13) who underwent gadopentate dimeglumine-enhanced dynamic MRI followed by ferucarbotran-enhanced gradient-echo imaging, the degree of parenchymal fibrosis was categorised into three groups based on the extent of reticulation and nodularity: (1) pre-cirrhotic or minimal fibrosis; (2) mild to moderate fibrosis; (3) advanced cirrhosis. Each group was evaluated for the presence of a sharp notch in the posterior-medial surface of the right lobe of the liver and expanded gallbladder fossa. The expanded gallbladder fossa sign gradually increased with an increasing degree of fibrosis (Group 1, 50%; Group 2, 61%; Group 3, 78%), and there was no significant difference (p>0.5) between hepatitis B (67%) and C (73%). In the case of the right posterior hepatic notch sign, only 6% of Group 1 and Group 2 patients were positive; 27% of hepatitis B patients and 90% of hepatitis C patients in Group 3 exhibited the sign (p<0.05). Owing to its low prevalence, even in advanced cirrhosis, the right posterior hepatic notch sign is of little value in the diagnosis of cirrhosis due to chronic hepatitis B virus infection, whereas an expanded gallbladder fossa could be used as a non-specific indicator of early fibrosis before the gross appearance of advanced hepatic fibrosis. PMID:19505965

  13. Interstitial fluid pressure and associated lymph node metastasis revealed in tumors by dynamic contrast-enhanced MRI.

    PubMed

    Hompland, Tord; Ellingsen, Christine; Øvrebø, Kirsti Marie; Rofstad, Einar K

    2012-10-01

    Elevated interstitial fluid pressure (IFP) in tumors can cause metastatic dissemination and treatment resistance, but its study poses a challenge because of a paucity of noninvasive imaging strategies. In this study, we address this issue by reporting the development of a noninvasive tool to assess tumor IFP and interstitial hypertension-induced lymph node metastasis. Using mouse xenograft models of several types of human cancer, we used gadolinium diethylene-triamine penta-acetic acid (Gd-DTPA) as a contrast agent for dynamic contrast-enhanced MRI (DCE-MRI). Immediately after Gd-DTPA administration, a high-signal-intensity rim was observed in the tumor periphery, which moved outward with time. Assuming the velocity of Gd-DTPA to be equal to the fluid flow velocity, we used a simple model of peritumoral interstitial fluid flow to calculate the fluid flow velocity at the tumor surface (v(0)) based on the rim movement. Significant positive correlations were found between v(0) and IFP in all tumor xenografts. Moreover, the primary tumors of metastasis-positive mice displayed higher IFP and v(0) than the primary tumors of metastasis-negative mice. Findings were confirmed in cervical cancer patients with pelvic lymph node metastases, where we found v(0) to be higher compared with patients without lymph node involvement (P < 0.00001). Together, these findings establish that Gd-DTPA-based DCE-MRI can noninvasively visualize tumor IFP, and they reveal the potential for v(0) determined by this method to serve as a novel general biomarker of tumor aggressiveness. PMID:23027087

  14. 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; Jérôme, 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

  15. 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.

  16. Comparison of Dynamic and Liver-Specific Gadoxetic Acid Contrast-Enhanced MRI versus Apparent Diffusion Coefficients

    PubMed Central

    Morelli, John N.; Michaely, Henrik J.; Meyer, Mathias M.; Rustemeyer, Thassilo; Schoenberg, Stefan O.; Attenberger, Ulrike I.

    2013-01-01

    Background Hepatic lesions often present diagnostic connundrums with conventional MR techniques. Hepatobiliary phase contrast-enhanced imaging with gadoxetic acid can aid in the characterization of such lesions. However, quantitative measures describing late-phase enhancement must be assessed relative to their accuracy of hepatic lesion classification. Purpose: To compare quantitative parameters in gadoxetic acid contrast-enhanced dynamic and hepatobiliary phase imaging versus apparent diffusion coefficients in hepatic lesion characterization. Material and Methods 57 patients with focal hepatic lesions on gadoxetic acid MR were included. Lesion enhancement at standard post-contrast time points and in the hepatobiliary phase (HB; 15 and 25 minutes post-contrast) was assessed via calculation of contrast (CR) and enhancement ratios (ER). Apparent diffusion coefficient (ADC) values were also obtained. Values for these parameters were compared among lesions and ROC analyses performed. Results: HB enhancement was greatest with FNH and adenomas. HB ER parameters but not HB CR could distinguish HCC from benign entities (0.9 ER ROC AUC versus 0.5 CR ROC AUC). There was no statistically significant difference found between the 15 and 25 minutes HB time points in detection of any lesion (p>0.4). ADC values were statistically significantly higher with hemangiomas (p<0.05) without greater accuracy in lesion detection relative to HB phase parameters. Conclusion Hepatobiliary phase gadoxetic acid contrast-enhanced MR characterizes focal hepatic lesions more accurately than ADC and conventional dynamic post-contrast time point enhancement parameters. ER values are generally superior to CR. No discernible benefit of 25 minute versus 15 minute delayed imaging is demonstrated. PMID:23805174

  17. Dual Manganese-Enhanced and Delayed Gadolinium-Enhanced MRI Detects Myocardial Border Zone Injury in a Pig Ischemia-Reperfusion Model

    PubMed Central

    Dash, Rajesh; Chung, Jaehoon; Ikeno, Fumiaki; Hahn-Windgassen, Annett; Matsuura, Yuka; Bennett, Mihoko V.; Lyons, Jennifer K.; Teramoto, Tomohiko; Robbins, Robert C.; McConnell, Michael V.; Yeung, Alan C.; Brinton, Todd J.; Harnish, Phillip P.; Yang, Phillip C.

    2011-01-01

    Background Delayed gadolinium (Gd) enhancement MRI (DEMRI) identifies non-viable myocardium, but is non-specific and may overestimate nonviable territory. Manganese (Mn2+)-enhanced MRI (MEMRI) denotes specific Mn2+ uptake into viable cardiomyocytes. We performed a dual-contrast myocardial assessment in a porcine ischemia-reperfusion (IR) model to test the hypothesis that combined DEMRI and MEMRI will identify viable infarct border zone (BZ) myocardium in vivo. Methods and Results Sixty-minute LAD ischemia-reperfusion injury (IR) was induced in 13 adult swine. Twenty-one days post-IR, 3T cardiac MRI was performed. MEMRI was obtained after injection (0.7 cc/kg) of Mn2+ contrast agent (EVP1001-1, Eagle Vision Pharmaceutical Corp.). DEMRI was then acquired after 0.2mmol/kg Gd injection. Left ventricular (LV) mass, infarct, and function were analyzed. Subtraction of MEMRI defect from DEMRI signal identified injured border zone myocardium. Explanted hearts were analyzed by 2,3,5-triphenyltetrazolium chloride (TTC) stain and tissue electron microscopy (TEM) to compare infarct, BZ, and remote myocardium. Average LV ejection fraction was reduced (30±7%). MEMRI and DEMRI infarct volumes correlated with TTC (MEMRI: r=0.78; DEMRI: r=0.75; p<0.004). MEMRI infarct volume percentage was significantly lower than DEMRI (14±4%* vs. 23±4%; *p<0.05). BZ MEMRI SNR was intermediate to remote and core infarct SNR (7.5±2.8* vs. 13.2±3.4 and 2.9±1.6; *p<0.0001), and DEMRI BZ SNR tended to be intermediate to remote and core infarct (8.4±5.4 vs. 3.3±0.6 and 14.3±6.6; p>0.05). TEM analysis exhibited preserved cell structure in BZ cardiomyocytes despite transmural DEMRI enhancement. Conclusions Dual-contrast MEMRI-DEMRI detects BZ viability within DEMRI infarct zones. This approach may identify injured, at-risk myocardium in ischemic cardiomyopathy. PMID:21719779

  18. Permeability Parameters Measured with Dynamic Contrast-Enhanced MRI: Correlation with the Extravasation of Evans Blue in a Rat Model of Transient Cerebral Ischemia

    PubMed Central

    Choi, Hyun Seok; Ahn, Sung Soo; Shin, Na-Young; Kim, Jinna; Kim, Jae Hyung; Lee, Jong Eun; Lee, Hye Yeon; Heo, Ji Hoe

    2015-01-01

    Objective The purpose of this study was to correlate permeability parameters measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using a clinical 3-tesla scanner with extravasation of Evans blue in a rat model with transient cerebral ischemia. Materials and Methods Sprague-Dawley rats (n = 13) with transient middle cerebral artery occlusion were imaged using a 3-tesla MRI with an 8-channel wrist coil. DCE-MRI was performed 12 hours, 18 hours, and 36 hours after reperfusion. Permeability parameters (Ktrans, ve, and vp) from DCE-MRI were calculated. Evans blue was injected after DCE-MRI and extravasation of Evans blue was correlated as a reference with the integrity of the blood-brain barrier. Correlation analysis was performed between permeability parameters and the extravasation of Evans blue. Results All permeability parameters (Ktrans, ve, and vp) showed a linear correlation with extravasation of Evans blue. Among them, Ktrans showed highest values of both the correlation coefficient and the coefficient of determination (0.687 and 0.473 respectively, p < 0.001). Conclusion Permeability parameters obtained by DCE-MRI at 3-T are well-correlated with Evans blue extravasation, and Ktrans shows the strongest correlation among the tested parameters. PMID:26175578

  19. Gd-EOB-DTPA-Enhanced MRI for Detection of Liver Metastases from Colorectal Cancer: A Surgeon's Perspective!

    PubMed Central

    Lafaro, Kelly J.; Roumanis, Panayota; Demirjian, Aram N.; Lall, Chandana; Imagawa, David K.

    2013-01-01

    Colorectal cancer affects over one million people worldwide annually, with the liver being the most common site of metastatic spread. Adequate resection of hepatic metastases is the only chance for a cure in a subset of patients, and five-year survival increases to 35% with complete resection. Traditionally, computed tomographic imaging (CT) was utilized for staging and to evaluate metastases in the liver. Recently, the introduction of hepatobiliary contrast-enhanced magnetic resonance imaging (MRI) agents including gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Eovist in the United States, Primovist in Europe, or Gd-EOB-DTPA) has proved to be a sensitive method for detection of hepatic metastases. Accurate detection of liver metastases is critical for staging of colorectal cancer as well as preoperative planning. PMID:23653860

  20. Comparison of gadoxetic acid and gadopentetate dimeglumine-enhanced MRI for HCC detection: prospective crossover study at 3?T

    PubMed Central

    Besa, Cecilia; Kakite, Suguru; Cooper, Nancy; Facciuto, Marcelo

    2015-01-01

    Background Gadoxetic acid and gadopentetate dimeglumine are gadolinium-based contrast agents (GBCAs) with an established role in HCC detection and characterization. Purpose To compare gadopentetate dimeglumine and gadoxetic acid-enhanced magnetic resonance imaging (MRI) for image quality and hepatocellular carcinoma (HCC) detection/conspicuity. Material and Methods In this IRB approved cross-over pilot prospective study, 12 patients (all men; mean age, 56 years) with chronic liver disease at risk of HCC underwent two repeat MRI examinations using gadopentetate dimeglumine and gadoxetic acid (mean interval between studies, 5 days). Two independent observers analyzed images for image quality and HCC detection/conspicuity. Per-lesion sensitivity, positive predictive value, quantitative enhancement, and lesion-to-liver contrast ratio were calculated for both contrast agents. Results There was no significant difference in image quality scores between both GBCAs (P?=?0.3). A total of 20 HCCs were identified with reference standard in 12 patients (mean size 2.6?cm, range, 1.0–5.0?cm). Higher sensitivity was seen for observer 1 for gadoxetic acid-set in comparison with gadopentetate dimeglumine-set (sensitivity increased from 85.7% to 92.8%), while no difference was noted for observer 2 (sensitivity of 78.5%). Lesion conspicuity was significantly higher on hepatobiliary phase (HBP) images compared to arterial phase images with both GBCAs for both observers (P?

  1. 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.

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

    PubMed Central

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

    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

  3. Improved fuzzy clustering algorithms in segmentation of DC-enhanced breast MRI.

    PubMed

    Kannan, S R; Ramathilagam, S; Devi, Pandiyarajan; Sathya, A

    2012-02-01

    Segmentation of medical images is a difficult and challenging problem due to poor image contrast and artifacts that result in missing or diffuse organ/tissue boundaries. Many researchers have applied various techniques however fuzzy c-means (FCM) based algorithms is more effective compared to other methods. The objective of this work is to develop some robust fuzzy clustering segmentation systems for effective segmentation of DCE - breast MRI. This paper obtains the robust fuzzy clustering algorithms by incorporating kernel methods, penalty terms, tolerance of the neighborhood attraction, additional entropy term and fuzzy parameters. The initial centers are obtained using initialization algorithm to reduce the computation complexity and running time of proposed algorithms. Experimental works on breast images show that the proposed algorithms are effective to improve the similarity measurement, to handle large amount of noise, to have better results in dealing the data corrupted by noise, and other artifacts. The clustering results of proposed methods are validated using Silhouette Method. PMID:20703716

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

    PubMed Central

    Mera Iglesias, Moisés; Aramburu Núñez, David; del Olmo Claudio, José Luis; Salvador Gómez, Francisco; Driscoll, Brandon; Coolens, Catherine; Alba Castro, José L.; Muñoz, 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

  5. 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.

  6. Structural effect on degradability and in vivo contrast enhancement of polydisulfide Gd(III) complexes as biodegradable macromolecular MRI contrast agents

    PubMed Central

    Zong, Yuda; Wang, Xuli; Jeong, Eun-Kee; Parker, Dennis L.; Lu, Zheng-Rong

    2009-01-01

    Structural effect of polydisulfide Gd(III) chelates on their in vitro degradability, and cardiovascular and tumor imaging in mice were evaluated as biodegradable macromolecular MRI contrast agents. Polydisulfide Gd(III) chelates, Gd-DTPA cystamine copolymers (GDCC), Gd-DTPA L-cystine copolymers (GDCP), Gd-DTPA D-cystine copolymers (dGDCP) and Gd-DTPA glutathione (oxidized) copolymers (GDGP), with different sizes and narrow molecular weight distribution were prepared and evaluated both in vitro and in vivo in mice bearing MDA-MB-231 tumor xenografts. Large steric hindrance around the disulfide bonds in GDGP resulted in greater T1 and T2 relaxivities than GDCC, GDCP and dGDCP. The degradability of the polydisulfide by the endogenous thiols decreased with an increase in steric effects around the disulfide bonds in the order of GDCC > GDCP, dGDCP > GDGP. The size and degradability of the contrast agents had significant impact on vascular contrast enhancement kinetics. The agents with large size and low degradability resulted in more prolonged vascular enhancement than the agents with small size and high degradability. It seems that the size and degradability of the agents did not significantly affect tumor enhancement. All agents resulted in significant contrast enhancement in tumor tissue. This study has demonstrated that the vascular enhancement kinetics of the polydisulfide MRI contrast agents can be controlled by their sizes and structures. The polydisulfide Gd(III) chelates are promising biodegradable macromolecular MRI contrast agents for MR angiography and cancer imaging. PMID:18814987

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

    E-print Network

    Menze, Bjoern Holger

    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 ...

  8. Variable Delay Multi-Pulse Train for Fast Chemical Exchange Saturation Transfer and Relayed-Nuclear Overhauser Enhancement MRI

    PubMed Central

    Xu, Jiadi; Yadav, Nirbhay N.; Bar-Shir, Amnon; Jones, Craig K.; Chan, Kannie W. Y.; Zhang, Jiangyang; Walczak, P.; McMahon, Michael T.; van Zijl, Peter C. M.

    2013-01-01

    Purpose Chemical exchange saturation transfer (CEST) imaging is a new MRI technology allowing the detection of low concentration endogenous cellular proteins and metabolites indirectly through their exchangeable protons. A new technique, variable delay multi-pulse CEST (VDMP-CEST), is proposed to eliminate the need for recording full Z-spectra and performing asymmetry analysis to obtain CEST contrast. Methods The VDMP-CEST scheme involves acquiring images with two (or more) delays between radiofrequency saturation pulses in pulsed CEST, producing a series of CEST images sensitive to the speed of saturation transfer. Subtracting two images or fitting a time series produces CEST and relayed-nuclear Overhauser enhancement CEST maps without effects of direct water saturation and, when using low radiofrequency power, minimal magnetization transfer contrast interference. Results When applied to several model systems (bovine serum albumin, crosslinked bovine serum albumin, l-glutamic acid) and in vivo on healthy rat brain, VDMP-CEST showed sensitivity to slow to intermediate range magnetization transfer processes (rate < 100–150 Hz), such as amide proton transfer and relayed nuclear Overhauser enhancement-CEST. Images for these contrasts could be acquired in short scan times by using a single radiofrequency frequency. Conclusions VDMP-CEST provides an approach to detect CEST effect by sensitizing saturation experiments to slower exchange processes without interference of direct water saturation and without need to acquire Z-spectra and perform asymmetry analysis. PMID:23813483

  9. 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; Aristizábal, 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

  10. In Vivo Mn-Enhanced MRI for Early Tumor Detection and Growth Rate Analysis in a Mouse Medulloblastoma Model12

    PubMed Central

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

    2014-01-01

    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 mm3. 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

  11. Pretreatment Diffusion-Weighted and Dynamic Contrast-Enhanced MRI for Prediction of Local Treatment Response in Squamous Cell Carcinomas of the Head and Neck

    PubMed Central

    Chawla, Sanjeev; Kim, Sungheon; Dougherty, Lawrence; Wang, Sumei; Loevner, Laurie A.; Quon, Harry; Poptani, Harish

    2013-01-01

    OBJECTIVE The objective of our study was to predict response to chemoradiation therapy in patients with head and neck squamous cell carcinoma (HNSCC) by combined use of diffusion-weighted imaging (DWI) and high-spatial-resolution, high-temporal-resolution dynamic contrast-enhanced MRI (DCE-MRI) parameters from primary tumors and metastatic nodes. SUBJECTS AND METHODS Thirty-two patients underwent pretreatment DWI and DCE-MRI using a modified radial imaging sequence. Postprocessing of data included motion-correction algorithms to reduce motion artifacts. The median apparent diffusion coefficient (ADC), volume transfer constant (Ktrans), extracellular extravascular volume fraction (ve), and plasma volume fraction (vp) were computed from primary tumors and nodal masses. The quality of the DCE-MRI maps was estimated using a threshold median chi-square value of 0.10 or less. Multivariate logistic regression and receiver operating characteristic curve analyses were used to determine the best model to discriminate responders from nonresponders. RESULTS Acceptable ?2 values were observed from 84% of primary tumors and 100% of nodal masses. Five patients with unsatisfactory DCE-MRI data were excluded and DCEMRI data for three patients who died of unrelated causes were censored from analysis. The median follow-up for the remaining patients (n = 24) was 23.72 months. When ADC and DCE-MRI parameters (Ktrans, ve, vp) from both primary tumors and nodal masses were incorporated into multivariate logistic regression analyses, a considerably higher discriminative accuracy (area under the curve [AUC] = 0.85) with a sensitivity of 81.3% and specificity of 75% was observed in differentiating responders (n = 16) from nonresponders (n = 8). CONCLUSION The combined use of DWI and DCE-MRI parameters from both primary tumors and nodal masses may aid in prediction of response to chemoradiation therapy in patients with HNSCC. PMID:23255739

  12. 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

  13. A case of occult contralateral breast cancer incidentally detected by contrast-enhanced MRI; report of a case with review of literature.

    PubMed

    Komatsu, Shuhei; Lee, Chol Joo; Hosokawa, Yohei; Hamashima, Takashi; Shirono, Koichi; Ichikawa, Daisuke; Okabe, Harumi; Kurioka, Hideaki; Yamagishi, Hisakazu; Oka, Takahiro

    2005-01-01

    We encountered a case of occult contralateral breast cancer, previously undetected by conventional imaging such as mammography (MMG) and ultrasonography (US), but incidentally detected by contrast-enhanced magnetic resonance imaging (CE-MRI). We present it here with a review of the literature. A 67-year-old Japanese woman was referred to our hospital in October 2000 because of a 1.5 cm right breast lump detected in a medical checkup. MMG, US and fine needle aspiration cytology revealed a cancerous lesion during the right breast. No mass lesion was palpable nor was any detected by MMG or US in the left breast. Bilateral breast CE-MRI was performed for more detailed evaluation. Consequently, an occult contralateral breast cancerous lesion was detected incidentally by CE-MRI, with the images showing rapid initial enhancement of time to signal intensity curves. Before surgery, bilateral breast lesions were diagnosed as invasive ductal carcinoma by open biopsy. She underwent bilateral breast conserving surgery with bilateral axillary lymph node dissection. The postoperative course was uneventful and no recurrence has been noted as of January 18th, 2004. CE-MRI of the contralateral breast should be of value as a routine screen in those patients with a known or suspected malignancy in one breast considering the limits of breast cancer detection by such conventional modalities as MMG and US. PMID:16286918

  14. A visual joke fMRI investigation into Theory of Mind and enhanced risk of schizophrenia.

    PubMed

    Marjoram, Dominic; Job, Dominic E; Whalley, Heather C; Gountouna, Viktoria-Eleni; McIntosh, Andrew M; Simonotto, Enrico; Cunningham-Owens, David; Johnstone, Eve C; Lawrie, Stephen

    2006-07-15

    Theory of Mind (ToM) or mentalizing is the ability of individuals to determine the intentions and behavior of others. This ability is known to be compromised in schizophrenia and has been shown to fluctuate with symptom severity. Neuropsychological investigations into relatives of individuals with schizophrenia have shown that some relatives also show a deficit in this area of social cognition. In order to address this state and trait issue, we investigated the performance of high-risk relatives of individuals with schizophrenia to those of a matched control group (n = 13) on a blocked design visual joke fMRI paradigm. The task involved looking at two sets of cartoon jokes, one set which required mentalizing abilities to understand the jokes and another set that did not require such abilities. Relatives were divided into two groups based on the presence (HR+, n = 12) or absence (HR-, n = 12) of positive symptoms. The task provided robust activations across the groups in areas previously associated with mentalizing abilities, such as the PFC, precuneus, and temporal lobes. Significant between-group activations were observed in the PFC (primarily BA6, 8, and 9) with the HR- activating significantly greater than the HR+ in these regions. Both a secondary state-specific analysis and a third post hoc analysis further investigating state effects showed significant PFC between-group differences. This study is the first time relatives of individuals with schizophrenia have been imaged using a ToM paradigm, and the results provide evidence of both a state and state-mediated trait effect. PMID:16624578

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

    PubMed Central

    Bäcker, 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 4.34±2.22 ml/min (healthy SD rats) and 2.34±0.90 ml/min (UNX rats) whereas MRI-GFR was 2.10±0.64 ml/min (SD rats) and 1.17±0.38 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

  16. Simultaneous measurement of kidney function by dynamic contrast enhanced MRI and FITC-sinistrin clearance in rats at 3 tesla: initial results.

    PubMed

    Zöllner, Frank G; Schock-Kusch, Daniel; Bäcker, 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 4.34 ± 2.22 ml/min (healthy SD rats) and 2.34 ± 0.90 ml/min (UNX rats) whereas MRI-GFR was 2.10 ± 0.64 ml/min (SD rats) and 1.17 ± 0.38 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

  17. Comparison of diffusion-weighted imaging and contrast-enhanced T1-weighted imaging on a single baseline MRI for demonstrating dissemination in time in multiple sclerosis

    PubMed Central

    2014-01-01

    Background The 2010 Revisions to the McDonald Criteria have established that dissemination in time (DIT) of multiple sclerosis (MS) can be demonstrated by simultaneous presence of asymptomatic gadolinium-enhancing and nonenhancing lesions on a single magnetic resonance imaging (MRI). However, gadolinium-based contrast agents (GBCAs) have contraindications. Diffusion-weighted imaging (DWI) can detect diffusion alterations in active inflammatory lesions. The purpose of this study was to investigate if DWI can be an alternative to contrast-enhanced T1-weighted imaging (CE T1WI) for demonstrating DIT in MS. Methods We selected patients with clinically definite MS and evaluated their baseline brain MRI. Asymptomatic lesions were identified as either hyperintense or nonhyperintense on DWI and enhancing or nonenhancing on CE T1WI. Fisher’s exact test was performed to determine whether the hyperintensity on DWI was related to the enhancement on CE T1WI (P?enhancement were calculated. Results Twenty-two patients with 384 demyelinating lesions that were hyperintense on T2-weighted imaging and more than 3 mm in size were recruited. The diffusion hyperintensity and lesion enhancement were significantly correlated (P <0.001). The sensitivity, specificity, PPV, NPV and accuracy were 100%, 67.9%, 32.3%, 100% and 72.1%, respectively. Conclusions A hyperintense DWI finding does not necessarily overlap with contrast enhancement. There are many false positives, possibly representing other stages of lesion development. Although DWI may not replace CE T1WI imaging to demonstrate DIT due to the low PPV, it may serve as a screening MRI sequence where the use of GBCAs is a concern. PMID:24885357

  18. Ferucarbotran (Resovist): a new clinically approved RES-specific contrast agent for contrast-enhanced MRI of the liver: properties, clinical development, and applications

    Microsoft Academic Search

    Peter Reimer; Thomas Balzer

    2003-01-01

    .   Ferucarbotran (Resovist) is the second clinically approved superparamagnetic iron oxide developed for contrast-enhanced MRI\\u000a of the liver. The purpose of this review is to provide an overview on the properties, clinical development, and application\\u000a of ferucarbotran. Safety data obtained during clinical phases I–III revealed a total of 162 adverse events within 1053 patients,\\u000a of which 75 were classified as

  19. 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

  20. 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

  1. 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

  2. Hepatic schwannoma: imaging findings on CT, MRI and contrast-enhanced ultrasonography.

    PubMed

    Ota, Yu; Aso, Kazunobu; Watanabe, Kenji; Einama, Takahiro; Imai, Koji; Karasaki, Hidenori; Sudo, Ryuji; Tamaki, Yosui; Okada, Mituyoshi; Tokusashi, Yosihiko; Kono, Toru; Miyokawa, Naoyuki; Haneda, Masakazu; Taniguchi, Masahiko; Furukawa, Hiroyuki

    2012-09-21

    A primary benign schwannoma of the liver is extremely rare and is difficult to preoperatively discriminate from a malignant tumor. We compared the imaging and pathological findings, and examined the possibility of preoperatively diagnosing a benign liver schwannoma. A 72-year-old woman was admitted to our hospital because of a 4.6-cm mass in the liver. A malignant tumor was suspected, and a right hepatectomy was performed. After this, the diagnosis of a primary benign schwannoma of the liver was made through pathological examination. Contrast-enhanced ultrasonography (CEUS) with Sonazoid showed minute blood flows into the septum and solid areas of the tumor in the vascular phase; most likely due to increased arterial flow associated with infiltration of chronic inflammatory cells. In the postvascular phase, CEUS showed contrast defect of cystic areas and delayed enhancement of solid areas; most likely due to aggregation of siderophores. Because discriminating between a benign and malignant schwannoma of the liver is difficult, surgery is generally recommended. However, the two key findings from CEUS may be useful in discriminating ancient schwannoma by recognizing the hemorrhage involved in the secondary degeneration and aggregation of siderophores. PMID:23002371

  3. Evaluation of image registration in subtracted 3D dynamic contrast-enhanced MRI of treated hepatocellular carcinoma.

    PubMed

    Sundarakumar, Dinesh K; Wilson, Gregory J; Osman, Sherif F; Zaidi, Sadaf F; Maki, Jeffrey H

    2015-02-01

    OBJECTIVE. The objective of our study was to quantify hepatic displacement between breath-holds in multiphasic contrast-enhanced MRI and assess the value of a 3D registration algorithm for displacement correction on subtracted images. MATERIALS AND METHODS. For this retrospective analysis, we evaluated MR images of 25 cirrhotic patients with treated hepatocellular carcinoma (HCC) and at least one coexisting small hepatic cyst that was hypointense on T1-weighted imaging. With the use of an automated 3D deformable registration algorithm, registered base and subtraction images were created using portal venous phase images as the baseline images. The relative displacement of the cysts over the dynamic phases was used to estimate hepatic displacement before and after registration. The width of the subtraction band artifact, HCC lesion conspicuity, and overall subtraction artifact level (i.e., image quality of the entire volume) of the subtraction images were evaluated before and after registration on a 5-point scale (1 = nondiagnostic, 5 = excellent image quality) by two blinded radiologists. Hepatic displacement and subtraction band artifact results were analyzed using the paired Student t test, and the results for HCC lesion conspicuity and image quality of the volume results were analyzed using the Wilcoxon signed rank test. Interobserver agreement was assessed using kappa statistics. RESULTS. The average total cyst displacement on unenhanced, arterial, and delayed phase images was significantly reduced by registration from 4.0, 3.2, and 4.6 mm, respectively, on pre-registered images to 2.4, 1.6, and 1.3 mm on postregistered images (p < 0.01). The mean HCC lesion conspicuity grade improved from 3.4 before registration to 4.4 after registration (p < 0.01), and the mean grade for image quality of the volume improved from 3.3 before registration to 4.6 after registration (p < 0.01). The average width of the subtraction band artifact decreased from 5.3 mm before registration to 2.4 mm after registration, from 6.1 mm before registration to 2.6 mm after registration, and from 5.2 mm before registration to 2.8 mm after registration for the arterial, portal venous, and delayed phase subtractions, respectively (p < 0.01). CONCLUSION. Automated registration of the liver in multiphasic MRI examinations reduced interphasic hepatic displacement, improved the conspicuity of the treated HCC lesion, and improved the overall subtraction image quality. PMID:25615750

  4. Methanol poisoning: characteristic MRI findings.

    PubMed

    Jain, Nirdesh; Himanshu, Dandu; Verma, Shailendra Prasad; Parihar, Anit

    2013-01-01

    Acute methanol intoxication is not an unusual poisoning. It can have serious neurological sequelae. We emphasize how neuroimaging can help in distinguishing methanol poisoning from other causes of acute unconsciousness in alcoholic patients such as hypoglycemic brain damage and carbon monoxide poisoning or head injury, which are frequently observed in alcoholic patients and are also responsible for altered sensorium. The most important findings in MR brain imaging in methanol poisoning have been bilateral putaminal hemorrhagic necrosis. Other less common findings are subcortical and deep white matter lesions, cerebral and cerebellar cortical lesions, and midbrain lesions, cerebral and intraventricular hemorrhage, and even enhancement of necrotic lesions, we found almost the entire spectrum of MRI findings in this patient with methanol poisoning. Neurological sequelae can entail the course and prognosis in methanol poisoning. The patient died because of ventilator-associated pneumonia that developed in the course of prolonged hospitalization. PMID:22634487

  5. 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.

  6. University of Utah Distinguished Professors Distinguished Professor Maurice Abravanel

    E-print Network

    van den Berg, Jur

    Distinguished Professor Henry Eyring Department of Chemistry (Deceased) Distinguished Professor J. Calvin Distinguished Professor Christopher Hacon Department of Mathematics Distinguished Professor Henry Harpending

  7. Comparing post-operative human breast specimen radiograph and MRI in lesion margin and volume assessment.

    PubMed

    Abe, Hiroyuki; Shimauchi, Akiko; Fan, Xiaobing; River, Jonathan N; Sattar, Husain; Mueller, Jeffrey; Karczmar, Gregory S; Newstead, Gillian M

    2012-01-01

    The purpose of this research is to evaluate the potential for identifying malignant breast lesions and their margins on large specimen MRI, in comparison to specimen radiography and clinical dynamic contrast enhanced MRI (DCE-MRI). Breast specimens were imaged with an MR scanner immediately after surgery, with an IRB-approved protocol and with the patients' informed consent. Specimen sizes were at least 5 cm in diameter and approximately 1 to 4 cm thick. Coronal and axial gradient echo MR images without fat suppression were acquired over the whole specimens using a 9.4T animal scanner. Findings on specimen MRI were compared with findings on specimen radiograph, and their volumes were compared with measurements obtained from clinical DCE-MRI. The results showed that invasive ductal carcinoma (IDC) lesions were easily identified using MRI and the margins were clearly distinguishable from nearby tissue. However, ductal carcinoma in situ (DCIS) lesions were not clearly discernible and were diffused with poorly defined margins on MRI. Calcifications associated with DCIS were visualized in all specimens on specimen radiograph. There is a strong correlation between the maximum diameter of lesions as measured by radiograph and MRI (r = 0.93), as well as the maximum diameter measured by pathology and radiograph/MRI (r>0.75). The volumes of IDC measured on specimen MRI were slightly smaller than those measured on DCE-MRI. Imaging of excised human breast lumpectomy specimens with high magnetic field MRI provides promising results for improvements in lesion identification and margin localization for IDC. However, there are technical challenges in visualization of DCIS lesions. Improvements in specimen imaging are important, as they will provide additional information to standard radiographic analysis. PMID:23149773

  8. Prospective evaluation of contrast-enhanced MRI in the depiction of peritoneal spread in primary or recurrent ovarian cancer

    Microsoft Academic Search

    Jens Ricke; Jalid Sehouli; Constanze Hach; Enrique Hänninen; Werner Lichtenegger; Roland Felix

    2003-01-01

    .   The purpose of this study was to assess the accuracy of MRI in the staging of intra-abdominal tumor seeding of ovarian carcinoma.\\u000a Fifty-seven patients with suspected primary or recurrent ovarian carcinoma were included in this study. All patients received\\u000a laparotomy within 8 weeks after MRI. The MRI protocol included fat-saturated T1-weighted spin-echo (SE) sequences pre- and\\u000a post i.v. application of

  9. Fractionated manganese injections: effects on MRI contrast enhancement and physiological measures in C57BL/6 mice.

    PubMed

    Grünecker, Barbara; Kaltwasser, Sebastian F; Peterse, Yorick; Sämann, Philipp G; Schmidt, Mathias V; Wotjak, Carsten T; Czisch, Michael

    2010-10-01

    Manganese-enhanced MRI (MEMRI) is an increasingly used imaging method in animal research, which enables improved T(1)-weighted tissue contrast. Furthermore accumulation of manganese in activated neurons allows visualization of neuronal activity. However, at higher concentrations manganese (Mn2+) exhibits toxic side effects that interfere with the animals' behaviour and well-being. Therefore, when optimizing MEMRI protocols, a compromise has to be found between minimizing side effects and intensifying image contrast. Recently, a low concentrated fractionated Mn2+ application scheme has been proposed as a promising alternative. In this study, we investigated effects of different fractionated Mn2+ dosing schemes on vegetative, behavioural and endocrine markers, and MEMRI signal contrast in C57BL/6N mice. Measurements of the animals' well-being included telemetric monitoring of body temperature and locomotion, control of weight and observation of behavioural parameters during the time course of the injection protocols. Corticosterone levels after Mn2+ application served as endocrine marker of the stress response. We compared three MnCl2? x 4H2O application protocols: 3 times 60?mg/kg with an inter-injection interval of 48?h, six times 30?mg/kg with an inter-injection interval of 48?h, and 8 times 30?mg/kg with an inter-injection interval of 24?h (referred to as 3?x?60/48, 6?x?30/48 and 8?x?30/24, respectively). Both the 6?x?30/48 and the 8?x?30/24 protocols showed attenuated effects on animals' well-being as compared to the 3?x?60/48 scheme. Best MEMRI signal contrast was observed for the 8?x?30/24 protocol. Together, these results argue for a fractionated application scheme such as 30?mg/kg every 24?h for 8 days to provide sufficient MEMRI signal contrast while minimizing toxic side effects and distress. PMID:20878969

  10. rf enhancement and shielding in MRI caused by conductive implants: dependence on electrical parameters for a tube model.

    PubMed

    Graf, Hansjörg; Steidle, Günter; Lauer, Ulrike A; Schick, Fritz

    2005-02-01

    Radio frequency (rf) eddy-currents induced in implants made of conductive material might cause significant image artifacts in magnetic resonance imaging (MRI) such as shielding of the lumen of vascular stents. rf alteration near metal parts was assessed theoretically in the approximation of alternating current electrodynamics: The implant was modeled as tube with diameter d(o), resistance R, and reactance Y, constituting the secondary winding of a transformer. The transmitter coil of the scanner acted as primary winding and generated the linearly polarized rf field B1,app. Tube axis was assumed parallel to B1,app. The results of the calculations were as follows: Ninety percent of the applied rf-field amplitude is reached in the lumen at a ratio chi=R/Y approximately 2. A rapid drop occurs with the reduction of chi, whereas a further increase of chi causes only a small effect. With chi approximately 1/d(o)(Y approximately d2o,R approximately d(o)), conditions for rf alteration clearly depend on the diameter of the tube. Inside tubes with smaller diameter, rf shielding is less pronounced. rf alteration increases in good approximation with the square root of the strength of the static field B0. The following experiments were carried out: Tubes of similar diameter (d(o) approximately 8 mm) made of material of different conductivity (Cu, Nitinol, carbon fiber reinforced plastic with three different fiber structures) were examined at B0=0.2 and 1.5 T in water phantoms. Tube axis was aligned perpendicular to B0 and spin-echo technique was applied. Local rf enhancement near the outer surface of the metal tubes was detected applying manual reduction of the transmitter amplitude. Shielding inside a carbon fiber tube with d(o) approximately 8 mm and inside a smaller tube with d(o)=3.3 mm was compared. Both tubes showed the same wall structure and thickness (d(w)=0.4 mm). All measurements confirmed the theoretical results. Consequences for the construction of vascular stents are discussed, as well as problems with image artifacts due to rf enhancement near solid conductive implants. PMID:15789577

  11. Pharmacokinetic parameters as a potential predictor of response to pharmacotherapy in benign prostatic hyperplasia: a preclinical trial using dynamic contrast-enhanced MRI.

    PubMed

    Jia, Guang; Heverhagen, Johannes T; Henry, Hannes; Polzer, Hans; Baudendistel, Klaus T; von Tengg-Kobligk, Hendrik; Levine, Andrea L; Rosol, Thomas J; Knopp, Michael V

    2006-07-01

    We sought to assess the possibility of using pharmacokinetic parameters as a predictor of response to benign prostatic hyperplasia (BPH) pharmacotherapy via a randomized, placebo-controlled, animal preclinical trial using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Twelve male beagles with BPH were enrolled in a preclinical experimental drug trial and divided into two randomized groups with six beagles each: one drug (finasteride) group and one placebo (control) group. Two baseline MRI examinations and three follow-ups during treatment were performed on a clinical 1.5-T MRI system using axial T1- and T2-weighted magnetic resonance images for prostate volume measurement and DCE-MRI for the assessment of prostate microcirculation. A total of 0.2 mmol/kg body weight of the Gd-based contrast agent was administered with an injection rate of 0.2 ml/s. The pharmacokinetic parameters, maximum enhancement ratio (MER), transfer constant and rate constant, were assessed to characterize the microcirculation in the parenchymal zone. The time-signal intensity curve from the external iliac artery was used as the arterial input function. The correlation between baseline evaluations (prostate volume and pharmacokinetic parameters) and therapy-induced prostate volume changes under finasteride treatment were assessed. The changes in prostate volume at the end of the trial exhibited a significant linear correlation to the initial parenchymal MER (P < .02) in the finasteride group. Larger prostate volume reductions coincided with smaller initial parenchymal MER. These findings show considerable promise of using parenchymal MER as a predictor of response to BPH pharmacotherapy with finasteride. PMID:16824967

  12. 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 [Department of Surgery, Ghent University Hospital, Ghent (Belgium)]. E-mail: Wim.ceelen@ugent.be; Smeets, Peter [Department of Radiology, Ghent University Hospital, Ghent (Belgium); Backes, Walter [Department of Radiology, Maastricht University Hospital, Maastricht (Netherlands); Van Damme, Nancy [Department of Gastroenterology, Ghent University Hospital, Ghent (Belgium); Boterberg, Tom [Department of Radiotherapy, Ghent University Hospital, Ghent (Belgium); Demetter, Pieter [Department of Pathology, Erasmus University Hospital, Brussels (Belgium); Bouckenooghe, Isabel [Department of Surgery, Ghent University Hospital, Ghent (Belgium); De Visschere, Marieke [Department of Surgery, Ghent University Hospital, Ghent (Belgium); Peeters, Marc [Department of Gastroenterology, Ghent University Hospital, Ghent (Belgium); Pattyn, Piet [Department of Surgery, Ghent University Hospital, Ghent (Belgium)

    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.

  13. Visualization and quantification of whole rat heart laminar structure using high-spatial resolution contrast-enhanced MRI

    PubMed Central

    Benoist, David; Benson, Alan P.; White, Ed; Tanner, Steven F.; Holden, Arun V.; Dobrzynski, Halina; Bernus, Olivier; Radjenovic, Aleksandra

    2012-01-01

    It has been shown by histology that cardiac myocytes are organized into laminae and this structure is important in function, both influencing the spread of electrical activation and enabling myocardial thickening in systole by laminar sliding. We have carried out high-spatial resolution three-dimensional MRI of the ventricular myolaminae of the entire volume of the isolated rat heart after contrast perfusion [dimeglumine gadopentate (Gd-DTPA)]. Four ex vivo rat hearts were perfused with Gd-DTPA and fixative and high-spatial resolution MRI was performed on a 9.4T MRI system. After MRI, cryosectioning followed by histology was performed. Images from MRI and histology were aligned, described, and quantitatively compared. In the three-dimensional MR images we directly show the presence of laminae and demonstrate that these are highly branching and are absent from much of the subepicardium. We visualized these MRI volumes to demonstrate laminar architecture and quantitatively demonstrated that the structural features observed are similar to those imaged in histology. We showed qualitatively and quantitatively that laminar architecture is similar in the four hearts. MRI can be used to image the laminar architecture of ex vivo hearts in three dimensions, and the images produced are qualitatively and quantitatively comparable with histology. We have demonstrated in the rat that: 1) laminar architecture is consistent between hearts; 2) myolaminae are absent from much of the subepicardium; and 3) although localized orthotropy is present throughout the myocardium, tracked myolaminae are branching structures and do not have a discrete identity. PMID:22021329

  14. Segmentation and Classification of Triple Negative Breast Cancers Using DCE-MRI

    Microsoft Academic Search

    Shannon C. Agner; Jun Xu; Hussain Fatakdawala; Shridar Ganesan; Anant Madabhushi; Sarah Englander; Mark Rosen; Kathleen Thomas; Mitchell D. Schnall; Michael D. Feldman; John Tomaszewski

    2009-01-01

    Triple-negative (TN) breast cancer has gained much interest recently due to its lack of response to receptor-targeted therapies and its ag- gressive clinical nature. In this study, we evaluate the ability of a computer-aided diagnosis (CAD) system to not only distinguish benign from malignant lesions on dynamic contrast-enhanced mag- netic resonance imaging (DCE-MRI), but also to quantitatively dis- tinguish triple

  15. In vivo monitoring of sorafenib therapy effects on experimental prostate carcinomas using dynamic contrast-enhanced MRI and macromolecular contrast media

    PubMed Central

    Schwarz, Bettina; Paprottka, Philipp M.; Sourbron, Steven; von Einem, Jobst C.; Dietrich, Olaf; Hinkel, Rabea; Clevert, Dirk A.; Bruns, Christiane J.; Reiser, Maximilian F.; Nikolaou, Konstantin; Wintersperger, Bernd J.

    2013-01-01

    Abstract Purpose: To investigate dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with macromolecular contrast media (MMCM) to monitor the effects of the multikinase inhibitor sorafenib on subcutaneous prostate carcinomas in rats with immunohistochemical validation. Materials and methods: Copenhagen rats, implanted with prostate carcinoma allografts, were randomized to the treatment group (n?=?8) or the control group (n?=?8). DCE-MRI with albumin-(Gd-DTPA)35 was performed at baseline and after 1 week using a clinical 3-Tesla system. The treatment group received sorafenib, 10?mg/kg body weight daily. Kinetic analysis yielded quantitative parameters of tumor endothelial permeability–surface area product (PS; ml/100?ml/min) and fractional blood volume (Vb, %). Tumors were harvested on day 7 for immunohistochemical analysis. Results: In sorafenib-treated tumors, PS (0.62?±?0.20 vs 0.08?±?0.09?ml/100?ml/min; P?MRI-assayed fractional blood volume Vb showed a highly significant correlation with tumor vascularity (RECA-1; r?=?0.87, P?MRI with MMCM demonstrated good, significant correlations with the immunohistochemically assessed antiangiogenic, antiproliferative, and proapoptotic effects of a 1-week, daily treatment course of sorafenib on experimental prostate carcinoma allografts. PMID:24380871

  16. Phase I Trial of Preoperative Chemoradiation Plus Sorafenib for High Risk Extremity Soft Tissue Sarcomas with Dynamic Contrast-Enhanced MRI Correlates

    PubMed Central

    Meyer, Janelle M.; Perlewitz, Kelly S.; Hayden, James B.; Doung, Yee-Cheen; Hung, Arthur Y.; Vetto, John T.; Pommier, Rodney F.; Mansoor, Atiya; Beckett, Brooke R.; Tudorica, Alina; Mori, Motomi; Holtorf, Megan L.; Afzal, Aneela; Woodward, William J.; Rodler, Eve T.; Jones, Robin L.; Huang, Wei; Ryan, Christopher W.

    2013-01-01

    Purpose We performed a phase I trial of the addition of sorafenib to a chemoradiotherapy regimen in patients with high-risk (intermediate/high grade, >5 cm) extremity soft tissue sarcoma (STS) undergoing limb salvage surgery. We conducted a correlative study of quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to assess response to treatment. Experimental Design Patients were treated at increasing dose levels of sorafenib (200 mg daily, 400 mg daily, 400 mg BID) initiated 14 days prior to 3 preoperative and 3 postoperative cycles of epirubicin/ifosfamide. 28 Gy of radiation was administered during cycle 2 with epirubicin omitted. The primary objective was to determine the maximum tolerated dose (MTD) of sorafenib. DCE-MRI was performed at baseline, after 2 weeks of sorafenib, and prior to surgery. The imaging data were subjected to quantitative pharmacokinetic analyses. Results 18 subjects were enrolled, of which 16 were evaluable. The MTD of sorafenib was 400 mg daily. Common grade 3–4 adverse events included neutropenia (94%), hypophosphatemia (75%), anemia (69%), thrombocytopenia (50%), and neutropenic fever/infection (50%). 38% developed wound complications requiring surgical intervention. The rate of ?95% histopathologic tumor necrosis was 44%. Changes in DCE-MRI biomarker ?Ktrans after 2 weeks sorafenib correlated with histologic response (R2=0.67, p = 0.012) at surgery. Conclusion The addition of sorafenib to preoperative chemoradiotherapy is feasible and warrants further investigation in a larger trial. DCE-MRI detected changes in tumor perfusion after 2 weeks of sorafenib and may be a minimally-invasive tool for rapid assessment of drug effect in STS. PMID:24132922

  17. Breast MRI in Patients with Unilateral Bloody and Serous-Bloody Nipple Discharge: A Comparison with Galactography

    PubMed Central

    Manganaro, Lucia; D'Ambrosio, Ilaria; Gigli, Silvia; Di Pastena, Francesca; Tardioli, Stefano; Framarino, Marialuisa; Ballesio, Laura

    2015-01-01

    Purpose. Assessing the role of breast MRI compared to galactography in patients with unilateral bloody or serous-bloody nipple discharge. Materials and Methods. Retrospective study including 53 unilateral discharge patients who performed galactography and MRI. We evaluated the capability of both techniques in identifying pathology and distinguishing between nonmalignant and malignant lesions. Lesions BIRADS 1/2 underwent follow-up, while the histological examination after surgery has been the gold standard to assess pathology in lesions BIRADS 3/4/5. The ROC analysis was used to test diagnostic MRI and galactography ability. Results. After surgery and follow-up, 8 patients had no disease (15%), 23 papilloma (43%), 11 papillomatosis (21%), 5 ductal cancer in situ (10%), and 6 papillary carcinoma (11%) diagnoses. Both techniques presented 100% specificity; MRI sensitivity was 98% versus 49% of galactography. Considering MRI, we found a statistical association between mass enhancement and papilloma (P < 0.001; AUC 0.957; CI 0.888–1.025), ductal enhancement and papillomatosis (P < 0.001; AUC 0.790; CI 0.623–0.958), segmental enhancement and ductal cancer in situ (P = 0.007; AUC 0.750; CI 0.429–1.071), and linear enhancement and papillary cancer (P = 0.011). Conclusions. MRI is a valid tool to detect ductal pathologies in patients with suspicious bloody or serous-bloody discharge showing higher sensitivity and specificity compared to galactography. PMID:25685810

  18. Abstract 45432 Automatic evaluation of the peri-infarct area of myocardial infarction from delayed enhancement MRI

    E-print Network

    Boyer, Edmond

    ) and spatial-weighted fuzzy clustering. Subjects and Methods DE-MRI images were acquired with PSIR sequence 10 was segmented as normal and pathologic areas via a GMM. By considering all images, the false positive pixels / Processing and quantification: imaging Authors: A. Lalande 1, 2 , V. Valindria 2 , M. Angue 1 , N. Vignon 1

  19. Whole Body MRI at 3T with Quantitative Diffusion Weighted Imaging and Contrast-Enhanced Sequences for the Characterization of Peripheral Lesions in Patients with Neurofibromatosis Type 2 and Schwannomatosis

    PubMed Central

    Fayad, Laura M.; Blakeley, Jaishri; Plotkin, Scott; Widemann, Brigitte; Jacobs, Michael A.

    2013-01-01

    Purpose. WB-MRI is mainly used for tumor detection and surveillance. The purpose of this study is to establish the feasibility of WB-MRI at 3T for lesion characterization, with DWI/ADC-mapping and contrast-enhanced sequences, in patients with neurofibromatosis type 2 (NF-2) and schwannomatosis. Materials and Methods. At 3T, WB-MRI was performed in 11 subjects (10 NF-2 and 1 schwannomatosis) with STIR, T1, contrast-enhanced T1, and DWI/ADC mapping (b = 50, 400, 800?s/mm2). Two readers reviewed imaging for the presence and character of peripheral lesions. Lesion size and features (signal intensity, heterogeneity, enhancement characteristics, and ADC values) were recorded. Descriptive statistics were reported. Results. Twenty-three lesions were identified, with average size of 4.6 ± 2.8?cm. Lesions were characterized as tumors (21/23) or cysts (2/23) by contrast-enhancement properties (enhancement in tumors, no enhancement in cysts). On T1, tumors were homogeneously isointense (5/21) or hypointense (16/21); on STIR, tumors were hyperintense and homogeneous (10/21) or heterogeneous (11/21); on postcontrast T1, tumors enhanced homogeneously (14/21) or heterogeneously (7/21); on DWI, tumor ADC values were variable (range 0.8–2.7), suggesting variability in intrinsic tumor properties. Conclusion. WB-MRI with quantitative DWI and contrast-enhanced sequences at 3T is feasible and advances the utility of WB-MRI not only to include detection, but also to provide additional metrics for lesion characterization. PMID:24967287

  20. Evaluation of a Novel Macromolecular Cascade-Polymer Contrast Medium for Dynamic Contrast-Enhanced MRI Monitoring of Antiangiogenic Bevacizumab Therapy in a Human Melanoma Model

    PubMed Central

    Cyran, Clemens C.; Fu, Yanjun; Rogut, Victor; Chaopathomkul, Bundit; Wendland, Michael F.; Shames, David M.; Brasch, Robert C.

    2013-01-01

    Rationale and Objectives To assess the applicability of a novel macromolecular polyethylene glycol (PEG)-core gadolinium contrast agent for monitoring early antiangiogenic effects of bevacizumab using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). Materials and Methods Athymic rats (n = 26) implanted with subcutaneous human melanoma xenografts underwent DCE-MRI at 2.0 T using two different macromolecular contrast agents. The PEG core cascade polymer PEG12,000-Gen4-(Gd-DOTA)16, designed for clinical development, was compared to the prototype, animal-only, macromolecular contrast medium (MMCM) albumin-(Gd-DTPA)35. The treatment (n = 13) and control (n = 13) group was imaged at baseline and 24 hours after a single dose of bevacizumab (1 mg) or saline to quantitatively assess the endothelial-surface permeability constant (KPS, ?L·min·100 cm3) and the fractional plasma volume (fPV,%), using a two-compartment kinetic model. Results Mean KPS values, assessed with PEG12,000-Gen4-(Gd-DOTA)16, declined significantly (P< .05) from 29.5 ± 10 ?L·min·100cm3 to 10.4±7.8 ?L·min·100 cm3 by 24 hours after a single dose of bevacizumab. In parallel, KPS values quantified using the prototype MMCM albumin-(Gd-DTPA)35 showed an analogous, significant decline (P < .05) in the therapy group. No significant effects were detected on tumor vascularity or on microcirculatory parameters in the control group between the baseline and the follow-up scan at 24 hours. Conclusion DCE-MRI enhanced with the novel MMCM PEG12,000-Gen4-(Gd-DOTA)16 was able to monitor the effects of bevacizumab on melanoma xenografts within 24 hours of a single application, validated by the prototype, animal-only albumin-(Gd-DTPA)35. PEG12,000-Gen4-(Gd-DOTA)16 may be a promising candidate for further clinical development as a macromolecular blood pool contrast MRI agent. PMID:24029057

  1. 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

  2. Accurate high-resolution measurements of 3-D tissue dynamics with registration-enhanced displacement encoded MRI.

    PubMed

    Gomez, Arnold D; Merchant, Samer S; Hsu, Edward W

    2014-06-01

    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

  3. University and Distinguished Professors

    E-print Network

    Suzuki, Masatsugu

    492 Faculty University and Distinguished Professors Listed below are persons who were members of the faculty of the State University of New York at Binghamton at the time of publication. Adjunct faculty, Bartle Distinguished Professor of Management Clifford D. Clark, University Professor Emeritus

  4. MRI findings including gadolinium-enhanced dynamic studies of malignant, mixed mesodermal tumors of the uterus: differentiation from endometrial carcinomas

    Microsoft Academic Search

    Takayuki Ohguri; Takatoshi Aoki; Hideyuki Watanabe; Katsumi Nakamura; Hajime Nakata; Yusuke Matsuura; Masamichi Kashimura

    2002-01-01

    .   Our objective was to evaluate the usefulness of MRI including dynamic study in differentiating malignant, mixed mesodermal\\u000a tumor (MMMT) from endometrial carcinoma (EC). The MR images were reviewed in 4 patients with histologically confirmed MMMT\\u000a and 11 patients with EC. Flow voids inside and\\/or around the tumors were seen in 2 patients with MMMT but not in any EC

  5. Enhanced Sympathetic Arousal in Response to fMRI Scanning Correlates with Task Induced Activations and Deactivations

    PubMed Central

    Muehlhan, Markus; Lueken, Ulrike; Siegert, Jens; Wittchen, Hans-Ulrich; Smolka, Michael N.; Kirschbaum, Clemens

    2013-01-01

    It has been repeatedly shown that functional magnetic resonance imaging (fMRI) triggers distress and neuroendocrine response systems. Prior studies have revealed that sympathetic arousal increases, particularly at the beginning of the examination. Against this background it appears likely that those stress reactions during the scanning procedure may influence task performance and neural correlates. However, the question how sympathetic arousal elicited by the scanning procedure itself may act as a potential confounder of fMRI data remains unresolved today. Thirty-seven scanner naive healthy subjects performed a simple cued target detection task. Levels of salivary alpha amylase (sAA), as a biomarker for sympathetic activity, were assessed in samples obtained at several time points during the lab visit. SAA increased two times, immediately prior to scanning and at the end of the scanning procedure. Neural activation related to motor preparation and timing as well as task performance was positively correlated with the first increase. Furthermore, the first sAA increase was associated with task induced deactivation (TID) in frontal and parietal regions. However, these effects were restricted to the first part of the experiment. Consequently, this bias of scanner related sympathetic activation should be considered in future fMRI investigations. It is of particular importance for pharmacological investigations studying adrenergic agents and the comparison of groups with different stress vulnerabilities like patients and controls or adolescents and adults. PMID:23967320

  6. Simultaneous molecular imaging of redox reactions monitored by Overhauser-enhanced MRI with 14N- and 15N-labeled nitroxyl radicals

    PubMed Central

    Utsumi, Hideo; Yamada, Ken-ichi; Ichikawa, Kazuhiro; Sakai, Kiyoshi; Kinoshita, Yuichi; Matsumoto, Shingo; Nagai, Mika

    2006-01-01

    MRI has provided significant clinical utility in the diagnosis of diseases and will become a powerful tool to assess phenotypic changes in genetically engineered animals. Overhauser enhanced MRI (OMRI), which is a double resonance technique, creates images of free radical distributions in small animals by enhancing the water proton signal intensity by means of the Overhauser effect. Several studies have demonstrated noninvasive assessment of reactive oxygen species generation in small animals by using low frequency electron spin resonance (ESR) spectroscopy/imaging and nitroxyl radicals. In vivo ESR signal intensities of nitroxyl radicals decrease with time after injection; and the decreases are enhanced by reactive oxygen species, generated in oxidative disease models in a site-specific manner. In this study, we show images of nitroxyl radicals with different isotopes by changing the external magnetic field for ESR irradiation between 14N and 15N nuclei in field-cycled OMRI. OMRI simultaneously obtained dual images of two individual chemical processes. Oxidation and reduction were monitored in a rate-dependent manner at nanometer scale by labeling membrane-permeable and -impermeable nitroxyl radicals with 14N and 15N nuclei. Phantom objects containing ascorbic acid-encapsulated liposomes with membrane-permeable radicals but not membrane-impermeable ones show a time-dependent decrease of the OMRI image intensity. The pharmacokinetics in mice was assessed with OMRI after radical administration. This OMRI technique with dual probes should offer significant applicability to nanometer scale molecular imaging and simultaneous assessment of independent processes in gene-modified animals. Thus, it may become a powerful tool to clarify mechanisms of disease and to monitor pharmaceutical therapy. PMID:16432234

  7. Simultaneous molecular imaging of redox reactions monitored by Overhauser-enhanced MRI with 14N- and 15N-labeled nitroxyl radicals.

    PubMed

    Utsumi, Hideo; Yamada, Ken-ichi; Ichikawa, Kazuhiro; Sakai, Kiyoshi; Kinoshita, Yuichi; Matsumoto, Shingo; Nagai, Mika

    2006-01-31

    MRI has provided significant clinical utility in the diagnosis of diseases and will become a powerful tool to assess phenotypic changes in genetically engineered animals. Overhauser enhanced MRI (OMRI), which is a double resonance technique, creates images of free radical distributions in small animals by enhancing the water proton signal intensity by means of the Overhauser effect. Several studies have demonstrated noninvasive assessment of reactive oxygen species generation in small animals by using low frequency electron spin resonance (ESR) spectroscopy/imaging and nitroxyl radicals. In vivo ESR signal intensities of nitroxyl radicals decrease with time after injection; and the decreases are enhanced by reactive oxygen species, generated in oxidative disease models in a site-specific manner. In this study, we show images of nitroxyl radicals with different isotopes by changing the external magnetic field for ESR irradiation between (14)N and (15)N nuclei in field-cycled OMRI. OMRI simultaneously obtained dual images of two individual chemical processes. Oxidation and reduction were monitored in a rate-dependent manner at nanometer scale by labeling membrane-permeable and -impermeable nitroxyl radicals with (14)N and (15)N nuclei. Phantom objects containing ascorbic acid-encapsulated liposomes with membrane-permeable radicals but not membrane-impermeable ones show a time-dependent decrease of the OMRI image intensity. The pharmacokinetics in mice was assessed with OMRI after radical administration. This OMRI technique with dual probes should offer significant applicability to nanometer scale molecular imaging and simultaneous assessment of independent processes in gene-modified animals. Thus, it may become a powerful tool to clarify mechanisms of disease and to monitor pharmaceutical therapy. PMID:16432234

  8. Parallel MRI Reconstruction Using Variance Partitioning Regularization

    E-print Network

    Parallel MRI Reconstruction Using Variance Partitioning Regularization Fa-Hsuan Lin,1,2* Fu be utilized to enhance the spatiotempo- ral resolution of MRI by employing the parallel imaging tech- nique set in parallel MRI data. The proposed Variance Partition- ing Regularization (VPR) method can improve

  9. Dynamic Contrast-Enhanced and Diffusion MRI Show Rapid and Dramatic Changes in Tumor Microenvironment in Response to Inhibition of HIF-1? Using PX-4781

    PubMed Central

    Jordan, Bénédicte F; Runquist, Matthew; Raghunand, Natarajan; Baker, Amanda; Williams, Ryan; Kirkpatrick, Lynn; Powis, Garth; Gillies, Robert J

    2005-01-01

    Abstract PX-478 is a new agent known to inhibit the hypoxia-responsive transcription factor, HIF-1?, in experimental tumors. The current study was undertaken in preparation for clinical trials to determine which noninvasive imaging endpoint(s) is sensitive to this drug's actions. Dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) magnetic resonance imaging (MRI) were used to monitor acute effects on tumor hemodynamics and cellularity, respectively. Mice bearing human xenografts were treated either with PX-478 or vehicle, and imaged over time. DW imaging was performed at three b values to generate apparent diffusion coefficient of water (ADCw) maps. For DCE-MRI, a macromolecular contrast reagent, BSA-Gd-DTPA, was used to determine vascular permeability and vascular volume fractions. PX-478 induced a dramatic reduction in tumor blood vessel permeability within 2 hours after treatment, which returned to baseline by 48 hours. The anti-VEGF antibody, Avastin, reduced both the permeability and vascular volume. PX-478 had no effect on the perfusion behavior of a drug-resistant tumor system, A-549. Tumor cellularity, estimated from ADCw, was significantly decreased 24 and 36 hours after treatment. This is the earliest significant response of ADC to therapy yet reported. Based on these preclinical findings, both of these imaging endpoints will be included in the clinical trial of PX-478. PMID:15967100

  10. Phase Differential Enhancement of FLIM to Distinguish FRET Components of a Biosensor for Monitoring Molecular Activity of Membrane Type 1 Matrix Metalloproteinase in Live Cells

    PubMed Central

    Eichorst, John Paul; Huang, He

    2012-01-01

    Fluorescence lifetime-resolved imaging microscopy (FLIM) has been used to monitor the enzymatic activity of a proteolytic enzyme, Membrane Type 1 Matrix Metalloproteinase (MT1-MMP), with a recently developed FRET-based biosensor in vitro and in live HeLa and HT1080 cells. MT1-MMP is a collagenaise that is involved in the destruction of extra-cellular matrix (ECM) proteins, as well as in various cellular functions including migration. The increased expression of MT1-MMP has been positively correlated with the invasive potential of tumor cells. However, the precise spatiotemporal activation patterns of MT1-MMP in live cells are still not well-established. The activity of MT1-MMP was examined with our biosensor in live cells. Imaging of live cells was performed with full-field frequency-domain FLIM. Image analysis was carried out both with polar plots and phase differential enhancement. Phase differential enhancement, which is similar to phase suppression, is shown to facilitate the differentiation between different conformations of the MT1-MMP biosensor in live cells when the lifetime differences are small. FLIM carried out in differential enhancement or phase suppression modes, requires only two acquired phase images, and permits rapid imaging of the activity of MT1-MMP in live cells. PMID:21519891

  11. Effect of B1+ field correction on Quantitative Dynamic contrast enhanced MRI of the breast at 3.0T

    E-print Network

    Bedair, Reem; Gilbert, Fiona

    2015-07-23

    of 10 seconds. The dynamic data was collected in 8 minutes 7 seconds. Post-acquisition processing and image analysis: MR images were reviewed on the diagnostic workstation by two radiologists (R.B, F.J.G) with 3 and 20 years experience in MR breast... 15];94(3):427–35. Available from: http://www.nature.com/doifinder/10.1038/sj.bjc.6602948 15. Rahbar H, Partridge SC, DeMartini WB, Thursten B, Lehman CD. Clinical and technical considerations for high quality breast MRI at 3 Tesla. J Magn Reson...

  12. Quantitative in vivo measurement of early axonal transport deficits in a triple transgenic mouse model of Alzheimer’s 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 Alzheimer’s 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

  13. In vivo tumor characterization using both MR and optical contrast agents with a hybrid MRI-DOT system

    NASA Astrophysics Data System (ADS)

    Lin, Yuting; Ghijsen, Michael; Thayer, David; Nalcioglu, Orhan; Gulsen, Gultekin

    2011-03-01

    Dynamic contrast enhanced MRI (DCE-MRI) has been proven to be the most sensitive modality in detecting breast lesions. Currently available MR contrast agent, Gd-DTPA, is a low molecular weight extracellular agent and can diffuse freely from the vascular space into interstitial space. Due to this reason, DCE-MRI has low sensitivity in differentiating benign and malignant tumors. Meanwhile, diffuse optical tomography (DOT) can be used to provide enhancement kinetics of an FDA approved optical contrast agent, ICG, which behaves like a large molecular weight optical agent due to its binding to albumin. The enhancement kinetics of ICG may have a potential to distinguish between the malignant and benign tumors and hence improve the specificity. Our group has developed a high speed hybrid MRI-DOT system. The DOT is a fully automated, MR-compatible, multi-frequency and multi-spectral imaging system. Fischer-344 rats bearing subcutaneous R3230 tumor are injected simultaneously with Gd-DTPA (0.1nmol/kg) and IC-Green (2.5mg/kg). The enhancement kinetics of both contrast agents are recorded simultaneously with this hybrid MRI-DOT system and evaluated for different tumors.

  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

    Microsoft Academic Search

    Candice Meyzer; Frédéric Dhermain; Denis Ducreux; Jean-Louis Habrand; Pascale Varlet; Christian Sainte-Rose; Christelle Dufour; Jacques Grill

    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

  15. Prognostic significance of parameters derived from co-registered 18F-fluorodeoxyglucose PET and contrast-enhanced MRI in patients with high-grade glioma

    PubMed Central

    Paldino, M J; Wong, T Z; Reardon, D A; Friedman, H S; Barboriak, D P

    2011-01-01

    Objective The aim of this study was to determine the prognostic significance of the volume and intensity of abnormal 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) accumulation within areas of contrast enhancement on post-therapeutic volumetric MRI. Methods A total of 10 patients with Grade III or IV glioma were treated with resection followed by intracavitary radiation therapy with 131I-labelled antitenascin monoclonal antibody. Patients underwent serial FDG-PET and 1.5 T MR imaging. For each patient, MR and FDG-PET image volumes at each time point were aligned using a rigid-body normalised mutual information algorithm. Contrast-enhancing regions of interest (ROIs) were defined using a semi-automated k-means clustering technique. Activity within the ROI on the co-registered PET scan was calculated as a ratio (mean activity ratio; MAR) to activity in contralateral normal-appearing white matter (NAWM). The PET lesion was defined as the portion of the ROI associated with activity greater than two standard deviations above the mean in NAWM. Survival was assessed using the logrank test. Results Larger contrast-enhancing ROIs were strongly associated with an increased MAR (r = 0.51; p<0.002). Enhancing lesions with an MAR >1.2 were associated with decreased survival (p<0.016). In nine patients who died, the MAR on PET correlated inversely with survival duration (r = ?0.43; p<0.01), whereas PET lesion volume did not. Conclusion Following intracavitary radiation therapy, the development of contrast-enhancing lesions that are associated with high mean FDG-PET accumulation suggests poor prognosis. PMID:20959370

  16. DCE-MRI Data Analysis for Cancer Area Classification

    E-print Network

    Castellani, Umberto

    DCE-MRI Data Analysis for Cancer Area Classification U. Castellani, M. Cristani, A. Daducci, P and functional parameters ob- tained by Dynamic Contrast-Enhanced MRI (DCE-MRI) techniques are analyzed, which in proposing a machine learning methodology to segment auto- matically these MRI data, by isolating tumor areas

  17. University of Utah Distinguished Professors Distinguished Professor Robert Adler

    E-print Network

    Tipple, Brett

    of Mathematics *Distinguished Professor Emeritus Richard H. Boyd Departments of Chemical & Fuels Engineering & Materials Science & Engineering Distinguished Professor Ellen Bromberg Department of Modern Dance of Bioengineering & Materials Science and Engineering Distinguished Professor Peter B. Armentrout Department

  18. Functional MRI Research Facility The Functional MRI Laboratory is dedicated to supporting research on the structures and functions of

    E-print Network

    Kamat, Vineet R.

    Functional MRI Research Facility The Functional MRI Laboratory is dedicated to supporting research on functional MRI and associated research tools. The Laboratory's mission is to maintain an environment that will enhance the excellence of research using fMRI and associated technologies by providing a well

  19. 2.3.' , MRI .

    E-print Network

    1 34.2.2014 2009. ".. )MRI(. - - -ELSC "- -, "- , ,' ,- - ,ELSC.8.,. ­"" ) , , "( . , , , . . , . , . . . . - - ),(. 0F 1 MRI . . MRI . 100. . . ·. ·-. · . · , . 1. #12;3 I.IV)(/ . . / . / /­ , . 1. ,., MRI,,. )-(. ):,'4.( 2. ·18,18. ·. ·. ·. · . 3. :,. :: ·-MRI

  20. Intracystic gadolinium-enhanced MRI in the evaluation of residual giant-cystic craniopharyngiomas in children: report of four cases.

    PubMed

    Muñoz, Alberto; Martínez-León, María; Vázquez, Élida; Pérez da Rosa, Sandra; Crespo, José

    2014-01-01

    Residual giant-cystic craniopharyngiomas are amenable to intracavitary bleomycin treatment. Radiologic identification of potential cyst leaks is of paramount for treatment decisions. This report describes our experience in the use of intracystic Gadolinium (Gd)-enhanced MR imaging to determine potential communications between the tumoral cysts and other intra-axial spaces in 4 pediatric patients with residual giant-cystic craniopharyngiomas in whom intracavitary bleomycin treatment was planned after the injection of .1-.2 mL of gadopentetate dimeglumine (Gd-DTPA). In three cases no leaks were found. In one case, whose previous water-soluble iodinated contrast-enhanced CT cystography was negative for leaks, intracystic Gd-enhanced MR showed intraventricular Gd enhancement. We conclude that MR imaging after intracystic administration of Gd-based contrast paramagnetic agents is useful in the detection of potential leaks in cases of giant residual craniopharyngiomas. PMID:23157657

  1. High-resolution fMRI Reveals Match Enhancement and Attentional Modulation in the Human Medial Temporal Lobe

    Microsoft Academic Search

    Nicole M. Dudukovic; Alison R. Preston; Jermaine J. Archie; Gary H. Glover; Anthony D. Wagner

    2011-01-01

    A primary function of the medial temporal lobe (MTL) is to signal prior encounter with behaviorally relevant stimuli. MTL match enhancement—increased activation when viewing previously encountered stimuli—has been observed for goal-relevant stimuli in nonhuman primates during delayed-match-to-sample tasks and in humans during more complex relational memory tasks. Match enhancement may alternatively reflect (a) an attentional response to familiar relative to

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

    PubMed

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

    2010-08-21

    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 K(trans), k(ep), v(p) and v(e) 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 sigma = 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. PMID:20679691

  3. 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.

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

    PubMed

    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 (15)N and (2)H 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 (T(1)) 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 (14)N- and (15)N-labeled carbamoyl-PROXYL showed the interaction between the electron and nuclear spins to be mainly dipolar in origin. Upon (2)H labeling, about 70% and 40% increases in enhancement for (15)N- and (14)N-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. PMID:16875854

  5. Deficits in axonal transport in hippocampal-based circuitry and the visual pathway in APP knock-out animals witnessed by manganese enhanced MRI

    PubMed Central

    Gallagher, Joseph J.; Zhang, Xiaowei; Ziomek, Greg; Jacobs, Russell E.; Bearer, Elaine L.

    2012-01-01

    Mounting evidence implicates axonal transport defects, typified by the presence of axonal varicosities with aberrant accumulations of cargo, as an early event in Alzheimer’s disease (AD) pathogenesis. Work identifying amyloid precursor protein (APP) as a vesicular motor receptor for anterograde axonal transport further implicates axonal transport in AD. Manganese-enhanced MRI (MEMRI) detects axonal transport dynamics in preclinical studies. Here we pursue an understanding of the role of APP in axonal transport in the central nervous system by applying MEMRI to hippocampal circuitry and to the visual pathway in living mice homozygous for either wild type or a deletion in the APP gene (n = 12 for each genotype). Following intra-ocular or stereotaxic hippocampal injection, we performed time-lapse MRI to detect Mn2+ transport. Three dimensional whole brain datasets were compared on a voxel-wise basis using within-group pair-wise analysis. Quantification of transport to structures connected to injection sites via axonal fiber tracts was also performed. Histology confirmed consistent placement of hippocampal injections and no observable difference in glial-response to the injections. APP ?/? mice had significantly reduced transport from the hippocampus to the septal nuclei and amygdala after 7 hours and reduced transport to the contralateral hippocampus after 25 hours; axonal transport deficits in the APP ?/? animals were also identified in the visual pathway. These data support a system-wide role for APP in axonal transport within the central nervous system and demonstrate the power of MEMRI for assessing neuronal circuitry involved in memory and learning. PMID:22500926

  6. Tumor Metabolism and Perfusion in Head and Neck Squamous Cell Carcinoma: Pretreatment Multimodality Imaging with 1H-Magnetic Resonance Spectroscopy, Dynamic Contrast-Enhanced MRI and 18F-FDG PET

    PubMed Central

    Jansen, Jacobus F.A.; Schöder, Heiko; Lee, Nancy Y.; Stambuk, Hilda. E.; Wang, Ya; Fury, Matthew G.; Patel, Snehal G.; Pfister, David G.; Shah, Jatin P.; Koutcher, Jason A.; Shukla-Dave, Amita

    2010-01-01

    Purpose To correlate proton magnetic resonance spectroscopy (1H-MRS), dynamic contrast-enhanced MRI (DCE-MRI) and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) in nodal metastases of patients with head and neck squamous cell carcinoma (HNSCC) for assessment of tumor biology. Additionally, pretreatment multimodality imaging (MMI) was evaluated for its efficacy in predicting short-term response to treatment. Methods and Materials Metastatic neck nodes were imaged with 1H-MRS, DCE-MRI and 18F-FDG PET in 16 patients with newly diagnosed HNSCC before treatment. Short-term radiological response was evaluated at 3–4 months. The correlations between 1H-MRS (choline concentration, Cho/W), DCE-MRI (volume transfer constant, Ktrans; volume fraction of the extravascular extracellular space, ve; and redistribution rate constant, kep) and 18F-FDG PET (standard uptake value, SUV; and total lesion glycolysis, TLG) were calculated using non-parametric Spearman rank correlation. To predict the short-term response, logistic regression analysis was performed. Results A significant positive correlation was found between Cho/W and TLG (? = 0.599, p = 0.031). Cho/W correlated negatively with heterogeneity measures std(ve) (? = ?0.691, p = 0.004) and std(kep) (? = ?0.704, p = 0.003). SUVmax values correlated strongly with MRI tumor volume (? = 0.643, p = 0.007). Logistic regression indicated that std(Ktrans) and SUVmean were significant predictors of short-term response (p < 0.07). Conclusion Pretreatment multi-modality imaging using 1H-MRS, DCE-MRI and 18F-FDG PET is feasible in HNSCC patients with nodal metastases. Additionally, combined DCE-MRI and 18F-FDG PET parameters were predictive of short-term response to treatment. PMID:21236594

  7. 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; McNemar’s 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

  8. Pathology-MRI Correlation of Hepatocarcinogenesis: Recent Update

    PubMed Central

    Huh, Jimi; Kim, Kyung Won; Kim, Jihun; Yu, Eunsil

    2015-01-01

    Understanding the important alterations during hepatocarcinogenesis as well as the characteristic magnetic resonance imaging (MRI) and histopathological features will be helpful for managing patients with chronic liver disease and hepatocellular carcinoma. Recent advances in MRI techniques, such as fat/iron quantification, diffusion-weighted images, and gadoxetic acid-enhanced MRI, have greatly enhanced our understanding of hepatocarcinogenesis. PMID:26018513

  9. Manganese-Enhanced MRI (MEMRI) via Topical Loading of Mn2+ Significantly Impairs Mouse Visual Acuity: A Comparison with Intravitreal Injection

    PubMed Central

    Lin, Tsen-Hsuan; Chiang, Chia-Wen; Trinkaus, Kathryn; Spees, William M.; Sun, Peng; Song, Sheng-Kwei

    2014-01-01

    Manganese enhanced MRI (MEMRI) with topical loading of MnCl2 provides comparable optic nerve enhancement as seen by intravitreal injection. However, the impact of this novel and noninvasive Mn2+ loading method on visual function requires further assessments. The objective of this study is to determine the optimal topical Mn2+ loading dosage for MEMRI and to assess visual function after MnCl2 loading. Intravitreal administration was performed to compare the two approaches of MnCl2 loading. Twenty-four hours after topical loading of 0, 0.5, 0.75, and 1M MnCl2, T1-weighted (T1W), T2-weighted (T2W), diffusion tensor image (DTI) and visual acuity were performed to determine the best topical loading dosage for MEMRI measurements and to assess the integrity of retina and optic nerves. Mice were perfusion fixed immediately after in vivo experiments for H&E and immunohistochemistry staining. Topical loading of 1 M MnCl2 damaged the retinal photoreceptor layer with no detectable damage to retina ganglion cell layers or prechiasmatic optic nerves. For the topical loading, 0.75-M MnCl2 was required to see sufficient enhancement of optic nerve. At this concentration the visual function was significantly affected, followed by a slow recovery. Intravitreal injection (0.25 ?L of 0.2 M MnCl2) slightly affected visual acuity with full recovery a day later. To conclude, intravitreal MnCl2 injection provides more reproducible results with less adverse side effects than topical loading. PMID:24436112

  10. Three-dimensional inversion recovery manganese-enhanced MRI of mouse brain using super-resolution reconstruction to visualize nuclei involved in higher brain function.

    PubMed

    Poole, Dana S; Plenge, Esben; Poot, Dirk H J; Lakke, Egbert A J F; Niessen, Wiro J; Meijering, Erik; van der Weerd, Louise

    2014-07-01

    The visualization of activity in mouse brain using inversion recovery spin echo (IR-SE) manganese-enhanced MRI (MEMRI) provides unique contrast, but suffers from poor resolution in the slice-encoding direction. Super-resolution reconstruction (SRR) is a resolution-enhancing post-processing technique in which multiple low-resolution slice stacks are combined into a single volume of high isotropic resolution using computational methods. In this study, we investigated, first, whether SRR can improve the three-dimensional resolution of IR-SE MEMRI in the slice selection direction, whilst maintaining or improving the contrast-to-noise ratio of the two-dimensional slice stacks. Second, the contrast-to-noise ratio of SRR IR-SE MEMRI was compared with a conventional three-dimensional gradient echo (GE) acquisition. Quantitative experiments were performed on a phantom containing compartments of various manganese concentrations. The results showed that, with comparable scan times, the signal-to-noise ratio of three-dimensional GE acquisition is higher than that of SRR IR-SE MEMRI. However, the contrast-to-noise ratio between different compartments can be superior with SRR IR-SE MEMRI, depending on the chosen inversion time. In vivo experiments were performed in mice receiving manganese using an implanted osmotic pump. The results showed that SRR works well as a resolution-enhancing technique in IR-SE MEMRI experiments. In addition, the SRR image also shows a number of brain structures that are more clearly discernible from the surrounding tissues than in three-dimensional GE acquisition, including a number of nuclei with specific higher brain functions, such as memory, stress, anxiety and reward behavior. PMID:24817644

  11. Facing contrast-enhancing gliomas: perfusion MRI in grade III and grade IV gliomas according to tumor area.

    PubMed

    Di Stefano, Anna Luisa; Bergsland, Niels; Berzero, Giulia; Farina, Lisa; Rognone, Elisa; Gastaldi, Matteo; Aquino, Domenico; Frati, Alessandro; Tomasello, Francesco; Ceroni, Mauro; Marchioni, Enrico; Bastianello, Stefano

    2014-01-01

    Tumoral neoangiogenesis characterizes high grade gliomas. Relative Cerebral Blood Volume (rCBV), calculated with Dynamic Susceptibility Contrast (DSC) Perfusion-Weighted Imaging (PWI), allows for the estimation of vascular density over the tumor bed. The aim of the study was to characterize putative tumoral neoangiogenesis via the study of maximal rCBV with a Region of Interest (ROI) approach in three tumor areas-the contrast-enhancing area, the nonenhancing tumor, and the high perfusion area on CBV map-in patients affected by contrast-enhancing glioma (grades III and IV). Twenty-one patients were included: 15 were affected by grade IV and 6 by grade III glioma. Maximal rCBV values for each patient were averaged according to glioma grade. Although rCBV from contrast-enhancement and from nonenhancing tumor areas was higher in grade IV glioma than in grade III (5.58 and 2.68; 3.01 and 2.2, resp.), the differences were not significant. Instead, rCBV recorded in the high perfusion area on CBV map, independently of tumor compartment, was significantly higher in grade IV glioma than in grade III (7.51 versus 3.78, P = 0.036). In conclusion, neoangiogenesis encompasses different tumor compartments and CBV maps appear capable of best characterizing the degree of neovascularization. Facing contrast-enhancing brain tumors, areas of high perfusion on CBV maps should be considered as the reference areas to be targeted for glioma grading. PMID:24800207

  12. Absolute reproducible quantification of Net Cerebral Blood Flow using Dynamic Susceptibility Contrast Enhanced MRI, and its application in disease

    Microsoft Academic Search

    M. L. J. Scott; N. A. Thacker; P. A. Bromiley; A. Jackson

    1 Abstract A novel analysis technique for the quantification of net cerebral blood flow using dynamic susceptibility contrast- enhanced magnetic resonance imaging is presented. The method is based on the spatial differentiation of the first pass time of arrival of the imaged contrast in each voxel to obtain the net mean transit time of contrast across a voxel and as

  13. Percentage of signal intensity loss for characterisation of focal liver lesions in patients with chronic liver disease using ferucarbotran-enhanced MRI.

    PubMed

    Chou, C-T; Chen, R-C; Chen, W-T; Lii, J-M

    2010-12-01

    The purpose of this study was to determine the percentage of signal intensity loss (PSIL) threshold for the characterisation of focal liver lesions among patients with chronic liver disease. 55 nodules in 49 patients with chronic liver disease who underwent ferucarbotran-enhanced MR studies were included. Among the 49 patients, 40 had liver cirrhosis and 9 had chronic hepatitis. 8 haemangiomas, 3 focal nodular hyperplasia, 9 dysplastic nodules and 12 well, 19 moderately and 4 poorly differentiated hepatocellular carcinomas (HCCs) were revealed. The PSIL, signal-to-noise ratio and contrast-to-noise ratio of each lesion type were calculated. The diagnostic performance of PSIL on ferucarbotran-enhanced T(2) weighted images (PSIL(T2WI)) and T(2) weighted fat-suppression images (PSIL(FS-T2WI)) that characterised hepatic tumours was compared with receiver operating characteristic (ROC) analysis. Using ROC analysis, the diagnostic performance of PSIL(FS-T2WI) was superior to that of PSIL(T2WI) (p = 0.01). The mean PSIL(FS-T2WI) of the benign lesions was significantly higher than that of HCC (p<0.001), and the mean PSIL(FS-T2WI) of well-differentiated HCC was significantly higher than that of moderately/poorly differentiated HCCs (p = 0.001). With a PSIL(FS-T2WI) threshold of 40% in lesions characterising ferucarbotran-enhanced FS-T2WI, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value were 88.6%, 95%, 90.9%, 96.9% and 82.6%, respectively. In conclusion, with ferucarbotran-enhanced FS-T2WI, a PSIL(FS-T2WI) threshold of 40% for characterising focal liver nodules among patients with chronic liver disease is recommended. It is useful for distinguishing HCC from benign nodules. PMID:20413445

  14. Nitroxyl radicals-modified dendritic poly(l-lysine) as a contrast agent for Overhauser-enhanced MRI.

    PubMed

    Niidome, Takuro; Gokuden, Risa; Watanabe, Kazuto; Mori, Takeshi; Naganuma, Tatsuya; Utsumi, Hideo; Ichikawa, Kazuhiro; Katayama, Yoshiki

    2014-01-01

    Overhauser-enhanced magnetic resonance imaging (OMRI), which is a double resonance technique, creates images of free radical distribution in animals by enhancing the water proton signal intensity by the overhauser effect. In this study, we constructed a contrast agent by combining PROXYL groups that have nitroxyl radicals with PEG-modified dendritic poly(l-lysine) that accumulates in the tumor by enhanced permeability and retention (EPR) effect. Addition of the PROXYL groups at the PEG chains' termini on KG6 was advantageous in OMRI, because the ESR signal of the nitroxyl radical was maintained without decay caused by mobility restriction, even if the PROXYL groups were attached at 25?mol% on one molecule. After intramuscular injection of the molecule modified at 25?mol%, that is, PR25-PEG-KG6, a significant OMRI signal was observed at the injected site. However, no signal was detected in the tumor after intravenous injection of PR25-PEG-KG6 to a tumor-bearing mouse, although PR25-PEG-KG6 itself accumulated in the tumor. The reason was that the nitroxyl radicals were immediately reduced in the blood after the injection, suggesting that use of stable nitroxyl radicals will enable detection of tumors by OMRI after intravenous injection. PMID:25088777

  15. Combined DCE- and DW-MRI in diagnosis of benign and malignant tumors of the tongue.

    PubMed

    Ai, Songtao; Zhu, Wenjing; Liu, Yu; Wang, Pingzhong; Yu, Qiang; Dai, Kerong

    2013-01-01

    The combination of dynamic contrast-enhanced (DCE) and diffusion-weighted (DW)-MRI adds important information to the findings obtained through conventional spin echo MRI. We aimed to determine the value of combined DW- and DCE-MRI in distinguishing benign from malignant tumors of the tongue and mouth floor. The apparent diffusion coefficient (ADC) maps were constructed, and the ADC values of the lesions were calculated from DW-MRI. The slopes were derived from time-intensity curves (TICs) from DCE-MRI. The ADC map for malignant tumors was lower compared with the benign lesions. The slope in the malignant tumors was significantly greater compared with the benign lesions. In malignant tumors, the ADC(b=500) threshold of <1.43 10(-3) mm2/s yielded a sensitivity, specificity, and accuracy of 74.6%, 83.3%, and 79.7%, respectively. For benign lesions, a slope threshold of <38.6 yielded a sensitivity, specificity, and accuracy of 80.3%, 74.5%, and 77.9%, respectively. Combined DCE- and DW-MR imaging may provide valuable information that allows for the differentiation between benign lesions and malignant tumors of the tongue and mouth floor. PMID:23747870

  16. An Active Two Channel 0.035” Guidewire for Interventional Cardiovascular MRI

    PubMed Central

    Kocaturk, Ozgur; Kim, Ann H.; Saikus, Christina E.; Guttman, Michael A.; Faranesh, Anthony Z.; Ozturk, Cengizhan; Lederman, Robert J.

    2009-01-01

    Purpose To develop an “active” (receiver-coil) clinical grade guidewire with enhanced visibility for MRI and favorable mechanical characteristics for interventional magnetic resonance imaging (MRI) procedures that require conspicuous intravascular instruments distinguishable from surrounding tissues. Materials and Methods We designed a 0.035-inch guidewire combining two antenna designs on separate channels. A loop antenna visualizes the tip, and a dipole antenna visualizes the whole shaft. We compared mechanical characteristics of this guidewire with X-ray alternatives, and tested MRI performance at 1.5T in vitro and in vivo in swine. Results Images reflected tip position within 0.97 ± 0.42 mm and afforded whole-shaft visibility under expected conditions without sacrificing device size or handling. We report tip stiffness, torquability and pushability comparable to commercial interventional guidewires. Conclusion Our clinical grade 0.035-inch active guidewire is conspicuous under MRI and has mechanical performance comparable to X-ray interventional guidewires. This may enable a range of interventional procedures using real-time MRI. PMID:19629968

  17. Chest MRI

    MedlinePLUS

    ... or standard x ray, MRI doesn't use radiation or pose any risk of cancer. Rarely, the contrast dye used for some chest MRIs may cause an allergic reaction or worsen kidney function in people who have ...

  18. Comparison of the hepatic perfusion index measured with gadolinium-enhanced volumetric MRI in controls and in patients with colorectal cancer

    Microsoft Academic Search

    J J Totman; R L O'GORMAN; P A KANE; J B KARANI

    2005-01-01

    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 T1 volume acquisitions

  19. 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.

  20. Role of quantitative pharmacokinetic parameter (transfer constant: Ktrans) in the characterization of breast lesions on MRI

    PubMed Central

    Amarnath, Jena; Sangeeta, Taneja; Mehta, Shashi Bhushan

    2013-01-01

    Background: The semi-quantitative analysis of the time–intensity curves in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has a limited specificity due to overlapping enhancement patterns after gadolinium administration. With the advances in technology and faster sequences, imaging of the entire breast can be done in a few seconds, which allows measuring the transit of contrast (transfer constant: Ktrans) through the vascular bed at capillary level that reflects quantitative measure of porosity/permeability of tumor vessels. Aim: Our study aims to evaluate the pharmacokinetic parameter Ktrans for enhancing breast lesions and correlate it with histopathology, and assess accuracy, sensitivity, and specificity of this parameter in discriminating benign and malignant breast lesions. Materials and Methods: One hundred and fifty-one women with 216 histologically proved enhancing breast lesions underwent high temporal resolution DCE-MRI for the early dynamic analysis for calculation of pharmacokinetic parameters (Ktrans) using standard two compartment model. The calculated values of Ktrans were correlated with histopathology to calculate the sensitivity, specificity, and accuracy. Results: Receiver operating characteristic (ROC) curve analysis revealed a mean Ktrans value of 0.56, which reliably distinguished benign and malignant breast lesions with a sensitivity of 91.1% and specificity of 90.3% with an overall accuracy of 89.3%. The area under curve (AUC) was 0.907. Conclusion: Ktrans is a reliable quantitative parameter for characterizing benign and malignant lesions in routine DCE-MRI of breasts. PMID:23986614

  1. Magnetic Resonance Imaging (MRI)

    MedlinePLUS

    ... the MRI table. A specially trained technician (or "tech") operates the MRI machine. He or she may ... can't stay still during MRI. Sometimes MRI techs sedate teens who have trouble relaxing inside the ...

  2. 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

  3. AUR memorial award--1988. MRI enhancement of perfused tissues using chromium labeled red blood cells as an intravascular contrast agent

    SciTech Connect

    Eisenberg, A.D.; Conturo, T.E.; Price, R.R.; Holburn, G.E.; Partain, C.L.; James, A.E. Jr. (Vanderbilt Univ. Medical Center, Nashville, TN (USA))

    1989-10-01

    It has been demonstrated that chromium (Cr) labeling significantly decreases the relaxation times of packed red blood cells (RBCs). In this study, the spin-lattice relaxation time (T1) of human red cells was shortened from 836 ms to 29 ms and the spin-spin relaxation time (T2) shortened from 134 ms to 18 ms, when the cells were labeled at a Cr incubation concentration of 50 mM. Labeling of canine cells at 50 mM resulted in a T1 of 36 ms and a T2 of 26 ms. A labeling concentration of 10 mM produced similar relaxation enhancement, with uptake of 47% of the available Cr, and was determined to be optimal. The enhancement of longitudinal and transverse relaxation rates (1/T1,-1/T2) per amount of hemoglobin-bound Cr are 6.9 s-1 mM-1 and 9.8 s-1 mM-1 respectively, different from those of a pure Cr+3 solution. Labeling cells at 10 mM decreased the survival half-time in vivo from 16.6 days to 4.7 days in dogs. No difference in red cell survival was found with the use of hetero-transfusion versus auto-transfusion of labeled RBCs. Significant shortening of the T1 (912 ms to 266 ms, P = .03) and T2 (90 ms to 70 ms, P = .006) of spleen and the T1 (764 ms to 282 ms, P = .005) and the T2 (128 ms to 86 ms, P = .005) of liver occurred when 10% of the RBC mass of dogs was exchanged with Cr labeled cells. Liver and spleen spin density changes (P greater than 0.23) and muscle spin density and relaxation changes (P greater than 0.4) were insignificant. The in vivo T1 of a canine spleen which had been infarcted did not change following transfusion with labeled cells, where the T1 of liver did shorten. We believe this preliminary study suggests that Cr labeled red cells may have the potential to become an intravascular magnetic resonance imaging contrast agent.

  4. 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

  5. Portable MRI

    SciTech Connect

    Espy, Michelle A. [Los Alamos National Laboratory

    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.

  6. Morphological and functional midbrain phenotypes in Fibroblast Growth Factor 17 mutant mice detected by Mn-enhanced MRI.

    PubMed

    Yu, Xin; Nieman, Brian J; Sudarov, Anamaria; Szulc, Kamila U; Abdollahian, Davood J; Bhatia, Nitin; Lalwani, Anil K; Joyner, Alexandra L; Turnbull, Daniel H

    2011-06-01

    With increasing efforts to develop and utilize mouse models of a variety of neuro-developmental diseases, there is an urgent need for sensitive neuroimaging methods that enable in vivo analysis of subtle alterations in brain anatomy and function in mice. Previous studies have shown that the brains of Fibroblast Growth Factor 17 null mutants (Fgf17(-/-)) have anatomical abnormalities in the inferior colliculus (IC)-the auditory midbrain-and minor foliation defects in the cerebellum. In addition, changes in the expression domains of several cortical patterning genes were detected, without overt changes in forebrain morphology. Recently, it has also been reported that Fgf17(-/-) mutants have abnormal vocalization and social behaviors, phenotypes that could reflect molecular changes in the cortex and/or altered auditory processing / perception in these mice. We used manganese (Mn)-enhanced magnetic resonance imaging (MEMRI) to analyze the anatomical phenotype of Fgf17(-/-) mutants in more detail than achieved previously, detecting changes in IC, cerebellum, olfactory bulb, hypothalamus and frontal cortex. We also used MEMRI to characterize sound-evoked activity patterns, demonstrating a significant reduction of the active IC volume in Fgf17(-/-) mice. Furthermore, tone-specific (16- and 40-kHz) activity patterns in the IC of Fgf17(-/-) mice were observed to be largely overlapping, in contrast to the normal pattern, separated along the dorsal-ventral axis. These results demonstrate that Fgf17 plays important roles in both the anatomical and functional development of the auditory midbrain, and show the utility of MEMRI for in vivo analyses of mutant mice with subtle brain defects. PMID:21356319

  7. Morphological and functional midbrain phenotypes in Fibroblast Growth Factor 17 mutant mice detected by Mn-enhanced MRI

    PubMed Central

    Yu, Xin; Nieman, Brian J.; Sudarov, Anamaria; Szulc, Kamila U.; Abdollahian, Davood J.; Bhatia, Nitin; Lalwani, Anil K.; Joyner, Alexandra L.; Turnbull, Daniel H.

    2011-01-01

    With increasing efforts to develop and utilize mouse models of a variety of neuro-developmental diseases, there is an urgent need for sensitive neuroimaging methods that enable in vivo analysis of subtle alterations in brain anatomy and function in mice. Previous studies have shown that the brains of Fibroblast Growth Factor 17 null mutants (Fgf17?/?) have anatomical abnormalities in the inferior colliculus (IC)–the auditory midbrain–and minor foliation defects in the cerebellum. In addition, changes in the expression domains of several cortical patterning genes were detected, without overt changes in forebrain morphology. Recently, it has also been reported that Fgf17?/? mutants have abnormal vocalization and social behaviors, phenotypes that could reflect molecular changes in the cortex and/or altered auditory processing / perception in these mice. We used manganese (Mn)-enhanced magnetic resonance imaging (MEMRI) to analyze the anatomical phenotype of Fgf17?/? mutants in more detail than achieved previously, detecting changes in IC, cerebellum, olfactory bulb, hypothalamus and frontal cortex. We also used MEMRI to characterize sound-evoked activity patterns, demonstrating a significant reduction of the active IC volume in Fgf17?/? mice. Furthermore, tone-specific (16- and 40-kHz) activity patterns in the IC of Fgf17?/? mice were observed to be largely overlapping, in contrast to the normal pattern, separated along the dorsal-ventral axis. These results demonstrate that Fgf17 plays important roles in both the anatomical and functional development of the auditory midbrain, and show the utility of MEMRI for in vivo analyses of mutant mice with subtle brain defects. PMID:21356319

  8. Multi-delay multi-parametric arterial spin-labeled perfusion MRI in acute ischemic stroke — Comparison with dynamic susceptibility contrast enhanced perfusion imaging?

    PubMed Central

    Wang, Danny J.J.; Alger, Jeffry R.; Qiao, Joe X.; Gunther, Matthias; Pope, Whitney B.; Saver, Jeffrey L.; Salamon, Noriko; Liebeskind, David S.

    2013-01-01

    The purpose of the present study was to present a multi-delay multi-parametric pseudo-continuous arterial spin labeling (pCASL) protocol with background suppressed 3D GRASE (gradient and spin echo) readout for perfusion imaging in acute ischemic stroke. PCASL data at 4 post-labeling delay times (PLD = 1.5, 2, 2.5, 3 s) were acquired within 4.5 min in 24 patients (mean age 79.7 ± 11.4 years; 11 men) with acute middle cerebral artery (MCA) stroke who also underwent dynamic susceptibility contrast (DSC) enhanced perfusion imaging. Arterial transit times (ATT) were estimated through the calculation of weighted delays across the 4 PLDs, which were included in the calculation of cerebral blood flow (CBF) and arterial cerebral blood volume (CBV). Mean perfusion parameters derived using pCASL and DSC were measured within MCA territories and infarct regions identified on diffusion weighted MRI. The results showed highly significant correlations between pCASL and DSC CBF measurements (r > = 0.70, p < = 0.0001) and moderately significant correlations between pCASL and DSC CBV measurements (r > = 0.45, p < = 0.027) in both MCA territories and infarct regions. ASL ATT showed correlations with DSC time to the maximum of tissue residual function (Tmax)(r = 0.66, p = 0.0005) and mean transit time (MTT)(r = 0.59, p = 0.0023) in leptomeningeal MCA territories. The present study demonstrated the feasibility for noninvasive multi-parametric perfusion imaging using ASL for acute stroke imaging. PMID:24159561

  9. 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 Central

    Nagarajan, Mahesh B.; Huber, Markus B.; Schlossbauer, Thomas; Leinsinger, Gerda; Krol, Andrzej; Wismüller, Axel

    2013-01-01

    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

  10. Hybrid DOT and MRI system

    NASA Astrophysics Data System (ADS)

    Gulsen, Gultekin; Birgul, Ozlem; Nalcioglu, Orhan

    2003-07-01

    Recently, there has been a great deal of interest in further improving the in-vivo characterization of tumors by interrogating tissues with multiple simultaneous image based measurement techniques that provide complementary information about the functional state of the tissue under investigation. Besides offering the possibility of complementary information, multi-modality techniques could also be used to improve the measurements done by either modality as well as providing cross validation measurements. Magnetic resonance imaging (MRI) and near-infrared diffuse optical tomography (DOT) are two techniques that, when combined, provide complementary structural and functional information. MRI can be used to obtain detailed structural and metabolic information regarding tumors. On the other hand, DOT can be used to determine local quantitative information regarding tumor composition and metabolism. Thus, a combined system consisting of MRI and DOT has the potential to enhance understanding of the complex biological processes in tumors. In this work, we describe the design of the hybrid DOT-MRI system.

  11. MRI-based preplanning using CT and MRI data fusion in patients with cervical cancer treated with 3D-based brachytherapy: feasibility and accuracy study

    Microsoft Academic Search

    Martin Dolezel; Karel Odrazka; Jan Zizka; Jaroslav Vanasek; Tereza Kohlova; Tomas Kroulik; Dusan Spitzer; Pavel Ryska; Michal Tichy; Milan Kostal; Lubica Jalcova

    PurposeMRI assisted radiation treatment planning enables enhanced target contouring. The purpose of this study is to analyze the feasibility and accuracy of CT and MRI data fusion for MRI-based treatment planning in an institution where an MRI scanner is not available in the radiotherapy department.

  12. Nanomaterials in Medicine Special Feature Sackler Colloquium: Preparation and initial characterization of biodegradable particles containing gadolinium-DTPA contrast agent for enhanced MRI

    Microsoft Academic Search

    Amber L. Doiron; Kevin Chu; Adeel Ali; Lisa Brannon-Peppas

    2008-01-01

    Accurate imaging of atherosclerosis is a growing necessity for timely treatment of the disease. Magnetic resonance imaging (MRI) is a promising technique for plaque imaging. The goal of this study was to create polymeric particles of a small size with high loading of diethylenetriaminepentaacetic acid gadolinium (III) (Gd-DTPA) and demonstrate their usefulness for MRI. A water-in-oil-in-oil double emulsion solvent evaporation

  13. FDG-PET SUV can distinguish between spinal sarcoidosis and myelopathy with canal stenosis.

    PubMed

    Sakushima, Ken; Yabe, Ichiro; Shiga, Tohru; Yashima-Yamada, Moemi; Tsuji-Akimoto, Sachiko; Terae, Satoshi; Sasaki, Hidenao

    2011-02-01

    Spinal cord sarcoidosis is a rare manifestation of sarcoidosis. Magnetic resonance imaging (MRI) of spinal cord sarcoidosis sometimes resembles that of the non-inflammatory spinal cord lesion. (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) is an effective method to detect both systemic and central nervous system lesions in sarcoidosis. This study compared the standard uptake value (SUV) of FDG-PET between spinal cord sarcoidosis and non-inflammatory spinal cord lesions. We retrospectively reviewed the records of patients who underwent both spinal MRI and FDG-PET scans. We used SUV to evaluate the FDG-PET uptake of the lesion. The region of interest was the center of high-intensity areas on T2-weighted MR images. We included three patients with spinal cord sarcoidosis, five with myelomalacia caused by cervical spondylosis or ossification of the posterior longitudinal ligament, one with spinal cord edema associated with cervical spondylosis, and one with spinal cord edema associated with dural arteriovenous fistula. The spinal cord sarcoidosis group had a significantly higher SUV (mean 4.38, range 3.30-4.93) than patients with the other diseases (mean 1.87, range 1.42-2.74). The SUV of FDG-PET thus may be able to distinguish spinal cord sarcoidosis from other non-inflammatory lesions. FDG-PET can play an important role in the diagnosis of spinal cord sarcoidosis because the gadolinium enhancement in MRI is sometimes seen in spondylotic myelopathy or vascular malformation. FDG-PET is informative for the accurate diagnosis of spinal cord sarcoidosis and may enable clinicians to start treatment at an earlier stage. PMID:20820799

  14. 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. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Radiology, Maastricht University Medical Center, Maastricht (Netherlands); Schoeder, Heiko [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Lee, Nancy Y. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Stambuk, Hilda E. [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Wang Ya [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Fury, Matthew G. [Department of Medical Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Patel, Senehal G. [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Pfister, David G. [Department of Medical Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Shah, Jatin P. [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Koutcher, Jason A. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Medical Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Shukla-Dave, Amita, E-mail: davea@mskcc.org [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    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.

  15. 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 0.3 mmol/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 180 minutes 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?

  16. 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, Jörn; Pohle-Fröhlich, 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

  17. Distinguishing modified gravity models

    E-print Network

    Brax, Philippe

    2015-01-01

    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 r...

  18. 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 ...

  19. MRI of Focal Liver Lesions.

    PubMed

    Albiin, Nils

    2012-05-01

    Magnetic resonance imaging, MRI has more advantages than ultrasound, computed tomography, CT, positron emission tomography, PET, or any other imaging modality in diagnosing focal hepatic masses. With a combination of basic T1 and T2 weighted sequences, diffusion weighted imaging, DWI, and hepatobiliary gadolinium contrast agents, that is gadobenate dimeglumine (Gd-BOPTA) and gadoxetic acid (Gd-EOB), most liver lesions can be adequately diagnosed. Benign lesions, as cyst, hemangioma, focal nodular hyperplasia, FNH or adenoma, can be distinguished from malignant lesions. In a non-cirrhotic liver, the most common malignant lesions are metastases which may be hypovascular or hypervascular. In the cirrhotic liver hepatocellular carcinoma, HCC, is of considerable importance. Besides, intrahepatic cholangiocarcinoma and other less common malignancies has to be assessed. In this review, the techniques and typical MRI features are presented as well as the new algorithm issued by American Association for the Study of the Liver Diseases (AASLD). PMID:23049491

  20. MRI of Focal Liver Lesions

    PubMed Central

    Albiin, Nils

    2012-01-01

    Magnetic resonance imaging, MRI has more advantages than ultrasound, computed tomography, CT, positron emission tomography, PET, or any other imaging modality in diagnosing focal hepatic masses. With a combination of basic T1 and T2 weighted sequences, diffusion weighted imaging, DWI, and hepatobiliary gadolinium contrast agents, that is gadobenate dimeglumine (Gd-BOPTA) and gadoxetic acid (Gd-EOB), most liver lesions can be adequately diagnosed. Benign lesions, as cyst, hemangioma, focal nodular hyperplasia, FNH or adenoma, can be distinguished from malignant lesions. In a non-cirrhotic liver, the most common malignant lesions are metastases which may be hypovascular or hypervascular. In the cirrhotic liver hepatocellular carcinoma, HCC, is of considerable importance. Besides, intrahepatic cholangiocarcinoma and other less common malignancies has to be assessed. In this review, the techniques and typical MRI features are presented as well as the new algorithm issued by American Association for the Study of the Liver Diseases (AASLD). PMID:23049491

  1. Environmentally responsive MRI contrast agents

    PubMed Central

    Davies, Gemma-Louise; Kramberger, Iris; Davis, Jason J.

    2015-01-01

    Biomedical imaging techniques can provide a vast amount of anatomical information, enabling diagnosis and the monitoring of disease and treatment profile. MRI uniquely offers convenient, non-invasive, high resolution tomographic imaging. A considerable amount of effort has been invested, across several decades, in the design of non toxic paramagnetic contrast agents capable of enhancing positive MRI signal contrast. Recently, focus has shifted towards the development of agents capable of specifically reporting on their local biochemical environment, where a switch in image contrast is triggered by a specific stimulus/biochemical variable. Such an ability would not only strengthen diagnosis but also provide unique disease-specific biochemical insight. This feature article focuses on recent progress in the development of MRI contrast switching with molecular, macromolecular and nanoparticle-based agents. PMID:24040650

  2. [Intramedullary glioma. Postoperative MRI aspects].

    PubMed

    Borocco, A; Idir, A; Joubert, E; Lacroix, C; Hurth, M; Doyon, D

    1995-06-01

    MRI is the standard exploration of intramedullary tumours. Following up the patients is of prime importance to detect and treat possible recurrences at an early stage. The purpose of this paper is to specify the postoperative MRI semiology of intraspinal gliomas. During the 1986-1992 period, 47 patients operated upon in the Bicêtre hospital for primary intraspinal tumours were followed up with high-field MR (1.5 Tesla, Signa, G.E.). The retrospective visual study was carried out by two neuro-radiologists. The patients' group consisted of 24 women and 23 men aged from 15 to 67 years (mean 38 years). The tumours treated were 29 ependymomas and 18 astrocytomas. Eighty-five MRI examinations were analysed. Most of them comprised at least two planes in T1 and T2-weighted spin echo sequences with gadolinium injection, then only T1-weighted spin echo sequences after gadolinium injection (0.1 mmol/kg). The mean postoperative follow up period in the 47 patients was 32 months (range 7 to 84 months). Contrast enhancement of the spinal cord was observed in 20 cases. In the 6 patients with recurrence (5 astrocytomas, 1 malignant ependymoma) there was a segmental increase of spinal cord volume with contrast enhancement after gadolinium injection. In 3 out of these 6 patients clinical deterioration appeared later than MRI semiology. In clinically stable patients neither enhancement nor increase in spinal cord size was found in 27 cases, and enhancement alone was noted in 12 cases. There was no reliable criterion in the analysis of post gadolinium signal enhancement that could be used to differentiate recurrence from cicatricial contrast enhancement.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7629570

  3. A case of occult contralateral breast cancer incidentally detected by contrast-enhanced mri; report of a case with review of literature

    Microsoft Academic Search

    Shuhei Komatsu; Chol Joo Lee; Yohei Hosokawa; Takashi Hamashima; Koichi Shirono; Daisuke Ichikawa; Harumi Okabe; Hideaki Kurioka; Hisakazu Yamagishi; Takahiro Oka

    2005-01-01

    We encountered a case of occult contralateral breast cancer, previously undetected by conventional imaging such as mammography\\u000a (MMG) and ultrasonography (US), but incidentally detected by contrastenhanced magnetic resonance imaging (CE-MRI). We present\\u000a it here with a review of the literature. A 67-year-old Japanese woman was referred to our hospital in October 2000 because\\u000a of a 1.5 cm right breast lump

  4. Enhancing the discrimination accuracy between metastases, gliomas and meningiomas on brain MRI by volumetric textural features and ensemble pattern recognition methods

    Microsoft Academic Search

    Pantelis Georgiadis; Dionisis Cavouras; Ioannis Kalatzis; Dimitris Glotsos; Emmanouil Athanasiadis; Spiros Kostopoulos; Koralia Sifaki; Menelaos Malamas; George Nikiforidis; Ekaterini Solomou

    Three-dimensional (3D) texture analysis of volumetric brain magnetic resonance (MR) images has been identified as an important indicator for discriminating among different brain pathologies. The purpose of this study was to evaluate the efficiency of 3D textural features using a pattern recognition system in the task of discriminating benign, malignant and metastatic brain tissues on T1 postcontrast MR imaging (MRI)

  5. Vitamin E ( d-alpha-tocopheryl-co-poly(ethylene glycol) 1000 succinate) micelles-superparamagnetic iron oxide nanoparticles for enhanced thermotherapy and MRI

    Microsoft Academic Search

    Prashant Chandrasekharan; Dipak Maity; Cai Xian Yong; Kai-Hsiang Chuang; Jun Ding; Si-Shen Feng

    2011-01-01

    We synthesized vitamin E TPGS (d-?-Tocopheryl-co-poly(ethylene glycol) 1000 succinate) micelles for superparamagnetic iron oxides formulation for nanothermotherapy and magnetic resonance imaging (MRI), which showed better thermal and magnetic properties, and in vitro cellular uptake and lower cytotoxicity as well as better in vivo therapeutic and imaging effects in comparison with the commercial Resovist® and the Pluronic®F127 micelles reported in the recent literature.

  6. Disruptive chemical doping in a ferritin-based iron oxide nanoparticle to decrease r2 and enhance detection with T1-weighted MRI.

    PubMed

    Clavijo Jordan, M Veronica; Beeman, Scott C; Baldelomar, Edwin J; Bennett, Kevin M

    2014-01-01

    Inorganic doping was used to create flexible, paramagnetic nanoparticle contrast agents for in vivo molecular magnetic resonance imaging (MRI) with low transverse relaxivity (r2). Most nanoparticle contrast agents formed from superparamagnetic metal oxides are developed with high r2. While sensitive, they can have limited in vivo detection due to a number of constraints with T2 or T2*-weighted imaging. T1-weighted imaging is often preferred for molecular MRI, but most T1-shortening agents are small chelates with low metal payload or are nanoparticles that also shorten T2 and limit the range of concentrations detectable with T1-weighting. Here we used tungsten and iron deposition to form doped iron oxide crystals inside the apoferritin cavity to form a WFe nanoparticle with a disordered crystal and un-coupled atomic magnetic moments. The atomic magnetic moments were thus localized, resulting in a principally paramagnetic nanoparticle. The WFe nanoparticles had no coercivity or saturation magnetization at 5 K and sweeping up to ± 20,000 Oe, while native ferritin had a coercivity of 3000 Oe and saturation at ± 20,000 Oe. This tungsten-iron crystal paramagnetism resulted in an increased WFe particle longitudinal relaxivity (r1) of 4870 mm(-1) s(-1) and a reduced transverse relaxivity (r2) of 9076 mm(-1) s(-1) compared with native ferritin. The accumulation of the particles was detected with T1-weighted MRI in concentrations from 20 to 400 nm in vivo, both injected in the rat brain and targeted to the rat kidney glomerulus. The WFe apoferritin nanoparticles were not cytotoxic up to 700 nm particle concentrations, making them potentially important for targeted molecular MRI. PMID:24764110

  7. Accurate determination of blood-brain barrier permeability using dynamic contrast-enhanced T1-weighted MRI: a simulation and in vivo study on healthy subjects and multiple sclerosis patients.

    PubMed

    Cramer, Stig P; Larsson, Henrik B W

    2014-10-01

    Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is increasingly used to estimate permeability in situations with subtle blood-brain 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 DCE-MRI 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

  8. Outcome Classification of Preschool Children With Autism Spectrum Disorders Using MRI Brain Measures

    Microsoft Academic Search

    Natacha Akshoomoff; Catherine Lord; Alan J. Lincoln; Rachel Y. Courchesne; Ruth A. Carper; Jeanne Townsend; Eric Courchesne

    2004-01-01

    ObjectiveTo 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.

  9. Research Report Gamma Oscillations Distinguish

    E-print Network

    Sederberg, Per B.

    of successful memory formation and self-cued recall, we tested 52 patients with drug-resistant epilepsy who hadResearch Report Gamma Oscillations Distinguish True From False Memories Per B. Sederberg,1 Andreas true from false memories, we analyzed intracranial elec- troencephalographic recordings while 52

  10. Cross-visit tumor sub-segmentation and registration with outlier rejection for dynamic contrast-enhanced MRI time series data.

    PubMed

    Buonaccorsi, G A; Rose, C J; O'Connor, J P B; Roberts, C; Watson, Y; Jackson, A; Jayson, G C; Parker, G J M

    2010-01-01

    Clinical trials of anti-angiogenic and vascular-disrupting agents often use biomarkers derived from DCE-MRI, typically reporting whole-tumor summary statistics and so overlooking spatial parameter variations caused by tissue heterogeneity. We present a data-driven segmentation method comprising tracer-kinetic model-driven registration for motion correction, conversion from MR signal intensity to contrast agent concentration for cross-visit normalization, iterative principal components analysis for imputation of missing data and dimensionality reduction, and statistical outlier detection using the minimum covariance determinant to obtain a robust Mahalanobis distance. After applying these techniques we cluster in the principal components space using k-means. We present results from a clinical trial of a VEGF inhibitor, using time-series data selected because of problems due to motion and outlier time series. We obtained spatially-contiguous clusters that map to regions with distinct microvascular characteristics. This methodology has the potential to uncover localized effects in trials using DCE-MRI-based biomarkers. PMID:20879391

  11. 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.

  12. 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

  13. 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

  14. Distinguishing Distributions Using Chernoff Information

    Microsoft Academic Search

    Thomas Baignères; Pouyan Sepehrdad; Serge Vaudenay

    2010-01-01

    \\u000a In this paper, we study the soundness amplification by repetition of cryptographic protocols. As a tool, we use the Chernoff\\u000a Information. We specify the number of attempts or samples required to distinguish two distributions efficiently in various\\u000a protocols. This includes weakly verifiable puzzles such as CAPTCHA-like challenge-response protocols, interactive arguments\\u000a in sequential composition scenario and cryptanalysis of block ciphers. As

  15. PRECISIONPNEUMATICROBOTFOR MRI-GUIDEDNEUROSURGERY

    E-print Network

    Webster III, Robert James

    PRECISIONPNEUMATICROBOTFOR MRI-GUIDEDNEUROSURGERY DavidB.Comber,DianaCardona,Robert of Energetic Systems Objective To provide a minimally invasive treatment for epilepsy in a closedbore MRI design objectives: ·Fully MRI compatible ­nonmagnetic and mostly plastic ·Safe operation ­Rod locks

  16. 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 >1.14×10?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 2–3 had significantly poorer neck control and overall survival rates than patients with scores of 0–1. 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

  17. 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

  18. Multi-parametric MRI-pathologic correlation of prostate cancer using tracked biopsies

    NASA Astrophysics Data System (ADS)

    Xu, Sheng; Turkbey, Baris; Kruecker, Jochen; Yan, Pingkun; Locklin, Julia; Pinto, Peter; Choyke, Peter; Wood, Bradford

    2010-02-01

    MRI is currently the most promising imaging modality for prostate cancer diagnosis due to its high resolution and multiparametric nature. However, currently there is no standard for integration of diagnostic information from different MRI sequences. We propose a method to increase the diagnostic accuracy of MRI by correlating biopsy specimens with four MRI sequences including T2 weighted MRI, Diffusion Weight Imaging, Dynamic Contrast Enhanced MRI and MRI spectroscopy. This method uses device tracking and image fusion to determine the specimen's position on MRI images. The proposed method is unbiased and cost effective. It does not substantially interfere with the standard biopsy workflow, allowing it to be easily accepted by physicians. A study of 41 patients was carried out to validate the approach. The performance of all four MRI sequences in various combinations is reported. Guidelines are given for multi-parametric imaging and tracked biopsy of prostate cancer.

  19. Divalent Metal Transporter, DMT1: A Novel MRI Reporter Protein

    PubMed Central

    Bartelle, Benjamin B.; Szulc, Kamila U.; Suero-Abreu, Giselle A.; Rodriguez, Joe J.; Turnbull, Daniel H.

    2012-01-01

    Manganese (Mn)-enhanced MRI (MEMRI) has found a growing number of applications in anatomical and functional imaging in small animals, based on the cellular uptake of Mn ions in the brain, heart and other organs. Previous studies have relied on endogenous mechanisms of paramagnetic Mn ion uptake and enhancement. To genetically control MEMRI signals, we reverse engineered a major component of the molecular machinery involved in Mn uptake, the divalent metal transporter, DMT1. DMT1 provides positive cellular enhancement in a manner that is highly sensitive and dynamic, allowing greater spatial and temporal resolution for MRI compared to previously proposed MRI reporters such as ferritin. We characterized the MEMRI signal enhancement properties of DMT1-expressing cells, both in vitro and in vivo in mouse models of cancer and brain development. Our results show that DMT1 provides an effective genetic MRI reporter for a wide range of biological and pre-clinical imaging applications. PMID:23065715

  20. Can breast MRI help in the management of women with breast cancer treated by neoadjuvant chemotherapy?

    Microsoft Academic Search

    R M L Warren; L G Bobrow; H M Earl; P D Britton; D Gopalan; A D Purushotham; G C Wishart; J R Benson; W Hollingworth; RML Warren

    2004-01-01

    Contrast-enhanced (CE) MRI was used to monitor breast cancer response to neoadjuvant chemotherapy. Patients underwent CE MRI before and after therapy, together with conventional assessment methods (CAM). CE MRI was carried out at 1.5 T in the coronal plain with 3D sequences before and after bolus injection. An expert panel determined chemotherapy response using both CE MRI and CAM. Histopathological

  1. Prostate MRI: Access to and Current Practice of Prostate MRI in the United States

    PubMed Central

    Leake, James L; Hardman, Rulon L; Ojili, Vijayanadh; Thompson, Ian; Shanbhogue, Alampady; Hernandez, Javier; Barentsz, Jelle

    2014-01-01

    Purpose Magnetic resonance imaging (MRI) of the prostate has increasingly become more important in clinical medicine due to the risk of over-detection of low-grade, low-volume prostate cancer as well as due to the poor sampling of transrectal ultrasound-guided prostate biopsy in high-risk patients. We sought to determine the access, imaging protocols, and indications for MRI imaging of the prostate in the United States. Materials and Methods A brief survey was sent through mailing lists to members of the Society of Abdominal Radiology and Texas Radiological Society. Results Thirty-six academic centers responded to the survey, 88.9% of which routinely perform prostate MRI. Nine centers routinely performed imaging at 1.5T with an endorectal coil (25%), 11 performed at 3.0T without an endorectal coil (31%), and 10 performed at 3.0T with an endorectal coil (28%). All institutions used T1-weighted axial and orthogonal T2-weighted sequences. Most groups used diffusion weighted imaging (94.7%) and dynamic contrast enhancement (81.6%). Only 21.1% of groups performing prostate MRI routinely performed magnetic resonance spectroscopy as part of their protocol. Conclusions Prostate MRI is becoming a commonly performed examination at academic institutions, with most locations performing prostate MRI at minimum standards. There is a need to educate non-academic practices regarding the addition of functional MRI techniques to anatomic techniques, increase the number of institutions that regularly perform prostate MRI, and increase access to direct MRI-guided biopsy in institutions that perform prostate MRI on a regular basis. PMID:24389134

  2. Functional MRI today Peter Bandettini

    E-print Network

    Baker, Chris I.

    Functional MRI today Peter Bandettini Section on Functional Imaging Methods, National Institute Abstract 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

  3. Final Report Distinguished Speaker Program (DSP) and

    E-print Network

    Zhou, Chongwu

    Final Report Distinguished Speaker Program (DSP) and Annual Technology Workshop (ATW) VSoE Research. To leverage USC ongoing technical work, we developed a monthly Distinguished Speaker Program (DSP). CGS DSP. A large number of monthly lectures under the Distinguished Speaker Program (DSP) were conducted

  4. Distinguishability of maximally entangled states

    SciTech Connect

    Ghosh, Sibasish; Kar, Guruprasad; Roy, Anirban [Institute of Mathematical Sciences, CIT Campus, Taramani, Chennai 600113 (India); Sarkar, Debasis [Department of Applied Mathematics, University of Calcutta, 92 APC Road, Kolkata 700009 (India)

    2004-08-01

    In 2x2, more than two orthogonal Bell states with a single copy can never be discriminated with certainty if only local operations and classical communication (LOCC) are allowed. We show here that more than d numbers of pairwise orthogonal maximally entangled states in dxd, which are in canonical form, used by Bennett et al. [Phys. Rev. Lett. 70, 1895 (1993)], can never be discriminated with certainty by LOCC, when single copies of the states are provided. Interestingly we show here that all orthogonal maximally entangled states, which are in canonical form, can be discriminated with certainty by LOCC if and only if two copies of each of the states are provided. We provide here a conjecture regarding the highly nontrivial problem of local distinguishability of any d or fewer numbers of pairwise orthogonal maximally entangled states in dxd (in the single copy case)

  5. Distinguishing Ichthyoses by Protein Profiling

    PubMed Central

    Rice, Robert H.; Bradshaw, Katie M.; Durbin-Johnson, Blythe P.; Rocke, David M.; Eigenheer, Richard A.; Phinney, Brett S.; Schmuth, Matthias; Gruber, Robert

    2013-01-01

    To explore the usefulness of protein profiling for characterization of ichthyoses, we here determined the profile of human epidermal stratum corneum by shotgun proteomics. Samples were analyzed after collection on tape circles from six anatomic sites (forearm, palm, lower leg, forehead, abdomen, upper back), demonstrating site-specific differences in profiles. Additional samples were collected from the forearms of subjects with ichthyosis vulgaris (filaggrin (FLG) deficiency), recessive X-linked ichthyosis (steroid sulfatase (STS) deficiency) and autosomal recessive congenital ichthyosis type lamellar ichthyosis (transglutaminase 1 (TGM1) deficiency). The ichthyosis protein expression patterns were readily distinguishable from each other and from phenotypically normal epidermis. In general, the degree of departure from normal was lower from ichthyosis vulgaris than from lamellar ichthyosis, parallel to the severity of the phenotype. Analysis of samples from families with ichthyosis vulgaris and concomitant modifying gene mutations (STS deficiency, GJB2 deficiency) permitted correlation of alterations in protein profile with more complex genetic constellations. PMID:24130705

  6. Automatic identification and classification of characteristic kinetic curves of breast lesions on DCE-MRI.

    PubMed

    Chen, Weijie; Giger, Maryellen L; Bick, Ulrich; Newstead, Gillian M

    2006-08-01

    Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) of the breast is being used increasingly in the detection and diagnosis of breast cancer as a complementary modality to mammography and sonography. Although the potential diagnostic value of kinetic curves in DCE-MRI is established, the method for generating kinetic curves is not standardized. The inherent reason that curve identification is needed is that the uptake of contrast agent in a breast lesion is often heterogeneous, especially in malignant lesions. It is accepted that manual region of interest selection in 4D breast magnetic resonance (MR) images to generate the kinetic curve is a time-consuming process and suffers from significant inter- and intraobserver variability. We investigated and developed a fuzzy c-means (FCM) clustering-based technique for automatically identifying characteristic kinetic curves from breast lesions in DCE-MRI of the breast. Dynamic contrast-enhanced MR images were obtained using a T1-weighted 3D spoiled gradient echo sequence with Gd-DTPA dose of 0.2 mmol/kg and temporal resolution of 69 s. FCM clustering was applied to automatically partition the signal-time curves in a segmented 3D breast lesion into a number of classes (i.e., prototypic curves). The prototypic curve with the highest initial enhancement was selected as the representative characteristic kinetic curve (CKC) of the lesion. Four features were then extracted from each characteristic kinetic curve to depict the maximum contrast enhancement, time to peak, uptake rate, and washout rate of the lesion kinetics. The performance of the kinetic features in the task of distinguishing between benign and malignant lesions was assessed by receiver operating characteristic analysis. With a database of 121 breast lesions (77 malignant and 44 benign cases), the classification performance of the FCM-identified CKCs was found to be better than that from the curves obtained by averaging over the entire lesion and similar to kinetic curves generated from regions drawn within the lesion by a radiologist experienced in breast MRI. PMID:16964864

  7. Superficial Siderosis of the Central Nervous System Induced by a Single-Episode of Traumatic Subarachnoid Hemorrhage: A Study Using MRI-Enhanced Gradient Echo T2 Star-Weighted Angiography

    PubMed Central

    Zhao, Hongwei; Wang, Jin; Lu, Zhonglie; Wu, Qingjie; Lv, Haijuan; Liu, Hu; Gong, Xiangyang

    2015-01-01

    The purpose of this study was to examine whether a single episode of traumatic subarachnoid hemorrhage (tSAH) could cause superficial siderosis of the central nervous system (SS-CNS).This study was approved by the local ethics committee. Thirty-two patients with a history of a single episode of tSAH were enrolled in the study. An episode of tSAH was confirmed in patients based on a CT scan or a lumbar puncture, and a follow-up examination was conducted at least six weeks after the brain trauma. A follow-up MRI examination was performed, using enhanced gradient echo T2 star-weighted angiography (ESWAN) to detect hemosiderin deposition on the cortical surface. The extent to which hemosiderin deposition was associated with several clinical factors was investigated. Various degrees of hemosiderin deposition were detected in 31 of 32 (96.9%) single-episode tSAH patients. Analysis of contingency tables revealed an association between the regions of subarachnoid bleeding based on CT images and the regions of hemosiderin deposition based on ESWAN images (?2 = 17.73, P<0.05). SS-CNS was determined to be a common consequence after a single episode of tSAH. The extent of hemosiderin deposition is closely correlated with the initial bleeding sites and bleeding volume. PMID:25647424

  8. MRI of stroke recovery.

    PubMed

    Jiang, Quan; Zhang, Zheng Gang; Chopp, Michael

    2010-02-01

    MRI is a vital tool for the measurement of acute stroke and has been used to visualize changes in activation patterns during stroke recovery. There is emerging interest on using MRI to monitor the structural substrates of spontaneous recovery and neurorestorative treatment of stroke. In this review, we describe the use of MRI and its associated challenges to measure vascular and neuronal remodeling in response to spontaneous and therapy-induced stroke recovery. We demonstrate that MRI methodologies may be used in real-time monitoring of recovery from stroke. PMID:20035069

  9. Distinguished Lecture Series EECS COLLOQUIUM

    E-print Network

    California at Irvine, University of

    Abstract The digital revolution is over. The bits won and have invaded every aspect of our life, changing technologies that will seamlessly merge the digital and physical worlds. I focus on creating technologies that can enhance and augment everything around us with interactive and digital data: humans, animals

  10. Contrast-enhanced magnetic resonance imaging of myocardium at risk

    Microsoft Academic Search

    David S Fieno; Raymond J Kim; Enn-Ling Chen; Jon W Lomasney; Francis J Klocke; Robert M Judd

    2000-01-01

    OBJECTIVESWe sought to determine the relationship of delayed hyperenhancement by contrast magnetic resonance imaging (MRI) to viable and nonviable myocardium within the region at risk throughout infarct healing.BACKGROUNDThe relationship of delayed MRI contrast enhancement patterns to injured but viable myocardium within the ischemic bed at risk has not been established.METHODSWe compared in vivo and ex vivo MRI contrast enhancement to

  11. 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.

  12. Local and Global Distinguishability in Quantum Interferometry

    SciTech Connect

    Durkin, Gabriel A. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States); Dowling, Jonathan P. [Hearne Institute for Theoretical Physics, Louisiana State University, Baton Rouge, Louisiana 70803 (United States)

    2007-08-17

    A statistical distinguishability based on relative entropy characterizes the fitness of quantum states for phase estimation. This criterion is employed in the context of a Mach-Zehnder interferometer and used to interpolate between two regimes of local and global phase distinguishability. The scaling of distinguishability in these regimes with photon number is explored for various quantum states. It emerges that local distinguishability is dependent on a discrepancy between quantum and classical rotational energy. Our analysis demonstrates that the Heisenberg limit is the true upper limit for local phase sensitivity. Only the ''NOON'' states share this bound, but other states exhibit a better trade-off when comparing local and global phase regimes.

  13. Abell Endowment Distinguished Lecture in Computer Engineering,

    E-print Network

    Abell Endowment Distinguished Lecture in Computer Engineering, in conjunction with the Electrical and Computer Engineering Seminar Series and the Computer Science Department Seminar Series "Real-time, High

  14. Nanoparticle-based multimodal PET/MRI probes.

    PubMed

    Garcia, Joel; Tang, Tang; Louie, Angelique Y

    2015-04-01

    The integration of PET and MRI modalities into a single hybrid imaging system has been demonstrated to synergistically compensate for the limitations of each modality, with the potential to enhance diagnostic accuracy and improve development of therapeutics. To take advantage of the progress of the hybrid PET/MRI hardware, nanoparticle-based probes are being developed for multimodal applications. In this paper, recent advances in the development of nanoparticle-based, multimodal PET/MRI probes are reviewed. Common MRI contrast agents, PET tracers and chelators and surface functionality that comprised PET/MRI nanoprobes reported in the last 10 years are summarized, followed by a description of the physical properties of these probes and their imaging applications. PMID:25955127

  15. Multiparametric-MRI in diagnosis of prostate cancer

    PubMed Central

    Ghai, Sangeet; Haider, Masoom A.

    2015-01-01

    Multiparametric-magnetic resonance imaging (mp-MRI) has shown promising results in diagnosis, localization, risk stratification and staging of clinically significant prostate cancer. It has also opened up opportunities for focal treatment of prostate cancer. Combinations of T2-weighted imaging, diffusion imaging, perfusion (dynamic contrast-enhanced imaging) and spectroscopic imaging have been used in mp-MRI assessment of prostate cancer, but T2 morphologic assessment and functional assessment by diffusion imaging remains the mainstay for prostate cancer diagnosis on mp-MRI. Because assessment on mp-MRI can be subjective, use of the newly developed standardized reporting Prostate Imaging and Reporting Archiving Data System scoring system and education of specialist radiologists are essential for accurate interpretation. This review focuses on the present status of mp-MRI in prostate cancer and its evolving role in the management of prostate cancer. PMID:26166962

  16. MRI in local staging of rectal cancer: an update

    PubMed Central

    Tapan, Ümit; Özbayrak, 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

  17. Computer-assisted analysis of peripheral zone prostate lesions using T2-weighted and dynamic contrast enhanced T1-weighted MRI

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

    In this study, computer-assisted analysis of prostate lesions was researched by combining information from two different magnetic resonance (MR) modalities: T2-weighted (T2-w) and dynamic contrast-enhanced (DCE) T1-w images. Two issues arise when incorporating T2-w images in a computer-aided diagnosis (CADx) system: T2-w values are position as well as sequence dependent and images can be misaligned due to patient movement during the acquisition. A method was developed that computes T2 estimates from a T2-w and proton density value and a known sequence model. A mutual information registration strategy was implemented to correct for patient movement. Global motion is modelled by an affine transformation, while local motion is described by a volume preserving non-rigid deformation based on B-splines. The additional value to the discriminating performance of a DCE T1-w-based CADx system was evaluated using bootstrapped ROC analysis. T2 estimates were successfully computed in 29 patients. T2 values were extracted and added to the CADx system from 39 malignant, 19 benign and 29 normal annotated regions. T2 values alone achieved a diagnostic accuracy of 0.85 (0.77-0.92) and showed a significantly improved discriminating performance of 0.89 (0.81-0.95), when combined with DCE T1-w features. In conclusion, the study demonstrated a simple T2 estimation method that has a diagnostic performance such that it complements a DCE T1-w-based CADx system in discriminating malignant lesions from normal and benign regions. Additionally, the T2 estimate is beneficial to visual inspection due to the removed coil profile and fixed window and level settings.

  18. 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 (µl 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 µl 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.

  19. 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.

  20. MRI Appearance of Prostatic Stromal Sarcoma in a Young Adult

    PubMed Central

    Sone, Teruki; Miyaji, Yoshiyuki; Kozuka, Yuji; Ito, Katsuyoshi

    2011-01-01

    Prostatic stromal sarcoma (PSS) is quite rare. Herein, we describe magnetic resonance imaging (MRI) features of a PSS identified in a 26-year-old man with dysuria and hematuria. MRI clearly depicted the extent and multinodular appearance of the tumor, which was mainly located in the central zone of the prostate. The tumor appeared as a heterogeneously signal-hyperintense mass with a pseudocapsule on T2-weighted imaging. Contrast-enhanced T1-weighted MRI showed necrotic portions in the gradually enhanced solid mass, and diffusion-weighted imaging permitted the accurate assessment of the local extent of the tumor. Thus, the appearance on MRI was quite different from that of adenocarcinoma of the prostate. PMID:21852915

  1. 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

  2. MRI Techniques for Prediction of Local Tumor Progression After High-Intensity Focused Ultrasonic Ablation of Prostate Cancer

    Microsoft Academic Search

    Chan Kyo Kim; Byung Kwan Park; Hyun Moo Lee; Sam Soo Kim; EunJu Kim; Kim CK; Lee HM; Kim SS

    OBJECTIVE. The purpose of this study was to evaluate the diagnostic performance of dynamic contrast-enhanced MRI (DCE-MRI) and of T2-weighted MRI with diffusion- weighted imaging (DWI) for predicting local tumor progression after high-intensity focused ultrasonic ablation of localized prostate cancer. MATERIALS AND METHODS. Twenty-seven patients who had increased levels of pros- tate-specific antigen after high-intensity focused ultrasonic ablation underwent MRI

  3. 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

  4. 10 CFR 1002.22 - Use of distinguishing flag.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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  5. 10 CFR 1002.22 - Use of distinguishing flag.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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  6. 10 CFR 1002.22 - Use of distinguishing flag.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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  7. 10 CFR 1002.22 - Use of distinguishing flag.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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  8. 10 CFR 1002.21 - Description of distinguishing flag.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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  9. 10 CFR 1002.21 - Description of distinguishing flag.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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  10. 10 CFR 1002.21 - Description of distinguishing flag.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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  11. 10 CFR 1002.21 - Description of distinguishing flag.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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  12. 10 CFR 1002.22 - Use of distinguishing flag.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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  13. 10 CFR 1002.21 - Description of distinguishing flag.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Description of distinguishing flag. 1002.21 Section 1002.21 Energy DEPARTMENT...GENERAL PROVISIONS) OFFICIAL SEAL AND DISTINGUISHING FLAG Distinguishing Flag § 1002.21 Description of distinguishing...

  14. MRI Scans - Multiple Languages: MedlinePlus

    MedlinePLUS

    ... 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 (Magnetic Resonance Imaging) ??????( ...

  15. Shoulder MRI scan

    MedlinePLUS

    ... contains no radiation. No side effects from the magnetic fields and radio waves have been reported. The most ... health care provider before the test. The strong magnetic fields created during an MRI can cause heart pacemakers ...

  16. Lumbar MRI scan

    MedlinePLUS

    ... have been no reported side effects from the magnetic fields and radio waves. The most common type of ... health care provider before the test The strong magnetic fields created during an MRI can cause heart pacemakers ...

  17. Cervical MRI scan

    MedlinePLUS

    ... have been no reported side effects from the magnetic fields and radio waves. The most common type of ... health care provider before the test The strong magnetic fields created during an MRI can cause heart pacemakers ...

  18. Knee MRI scan

    MedlinePLUS

    ... have been no reported side effects from the magnetic fields and radio waves. The most common type of ... health care provider before the test. The strong magnetic fields created during an MRI can cause heart pacemakers ...

  19. Arm MRI scan

    MedlinePLUS

    ... have been no reported side effects from the magnetic fields and radio waves. The most common type of ... health care provider before the test The strong magnetic fields created during an MRI can cause heart pacemakers ...

  20. Sinus MRI scan

    MedlinePLUS

    ... radio waves instead of radiation. Signals from the magnetic field bounce off your body and are sent to ... not as close to the body. The strong magnetic fields created during an MRI can interfere with pacemakers ...

  1. Breast MRI scan

    MedlinePLUS

    ... contains no radiation. No side effects from the magnetic fields and radio waves have been reported. The most ... health care provider before the test. The strong magnetic fields created during an MRI can make heart pacemakers ...

  2. Abdominal MRI scan

    MedlinePLUS

    Nuclear magnetic resonance - abdomen; NMR - abdomen; Magnetic resonance imaging - abdomen; MRI of the abdomen ... used to look at: Blood flow in the abdomen Blood vessels in the abdomen The cause of ...

  3. Pituitary macroadenoma and diaphragma sellae meningioma: differential diagnosis on MRI

    Microsoft Academic Search

    P. Cappabianca; S. Cirillo; A. Alfieri; A. D'Amico; F. Maiuri; G. Mariniello; F. Caranci; E. de Divitiis

    1999-01-01

    Diaphragma sellae meningiomas are unusual tumours often not distinguished from pituitary macroadenomas. Preoperative differentiation\\u000a is essential, because the trans-sphenoidal approach is used for surgical removal of adenomas, while meningiomas are approached\\u000a via a craniotomy. We reviewed five patients in whom a diaphragma sellae meningioma was initially diagnosed as a nonsecreting\\u000a pituitary macroadenoma. MRI criteria for differential diagnosis are discussed. The

  4. Microtesla MRI with dynamic nuclear polarization.

    PubMed

    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. PMID:20843715

  5. 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

  6. EEG-informed fMRI analysis during a hand grip task: estimating the relationship between EEG rhythms and the BOLD signal

    PubMed Central

    Sclocco, Roberta; Tana, Maria G.; Visani, Elisa; Gilioli, Isabella; Panzica, Ferruccio; Franceschetti, Silvana; Cerutti, Sergio; Bianchi, Anna M.

    2014-01-01

    In the last decade, an increasing interest has arisen in investigating the relationship between the electrophysiological and hemodynamic measurements of brain activity, such as EEG and (BOLD) fMRI. In particular, changes in BOLD have been shown to be associated with changes in the spectral profile of neural activity, rather than with absolute power. Concurrently, recent findings showed that different EEG rhythms are independently related to changes in the BOLD signal: therefore, it would be also important to distinguish between the contributions of the different EEG rhythms to BOLD fluctuations when modeling the relationship between the two signals. Here we propose a method to perform EEG-informed fMRI analysis where the changes in the spectral profile are modeled, and, at the same time, the distinction between rhythms is preserved. We compared our model with two other frequency-dependent regressors modeling using simultaneous EEG-fMRI data from healthy subjects performing a motor task. Our results showed that the proposed method better captures the correlations between BOLD signal and EEG rhythms modulations, identifying task-related, well localized activated volumes. Furthermore, we showed that including among the regressors also EEG rhythms not primarily involved in the task enhances the performance of the analysis, even when only correlations with BOLD signal and specific EEG rhythms are explored. PMID:24744720

  7. F-18 FDG PET/MRI findings of primary breast lymphoma in two cases: FDG PET/MRI findings of primary breast lymphoma.

    PubMed

    Kong, Eun Jung; Cho, Ihn Ho

    2015-01-01

    We present the integrated positron emission tomography (PET)/magnetic resonance imaging (MRI) findings of diffuse large B-cell lymphoma involving the breast in two women. They were admitted with palpable breast masses. PET/MRI revealed high (18)F-fluorodeoxyglucose (FDG) uptake in multinodular enhancing masses without other FDG-avid foci. Diffusion-weighted imaging showed restricted water diffusion and dynamic contrast MRI showed rapid increase and washout kinetics. High FDG accumulation in tumor is related to washout kinetics. We present the usefulness of integrated PET/MRI for lesion characterization and total body staging in breast lymphoma. PMID:25748090

  8. `Access' report......................... 2 Distinguished lecture............. 3

    E-print Network

    Minnesota, University of

    Distinguished Service Award: Donna Allan is a "wonderful men- tor" to many women in transportation involved edu- cation, outreach, and evaluation efforts, including surveys of area residents. The work has

  9. 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...

  10. Optimized design and analysis ofOptimized design and analysis of sparse-sampling fMRI experimentssparse-sampling fMRI experiments

    E-print Network

    Gabrieli, John

    ­ Saturates activation of auditory cortices · Head motion during vocal responses adds noise, impedes timeseries ­ Ignores dynamic properties of hemodynamic response ­ Cannot distinguish the contributionB SNR ­ From actual resting fMRI · Compare Models: ­ 10,000 simulations in R #12;Tyler Perrachione

  11. Generation of macroscopically distinguishable quantum states and detection by the squeezed-vacuum technique

    NASA Astrophysics Data System (ADS)

    Tombesi, Paolo; Mecozzi, Antonio

    1987-10-01

    Here it is shown that, for a wide class of nonlinear Hamiltonians, an essentially classical initial state will evolve into the coherent superposition of distinguishable quantum states. The detection of the interference fringes can be performed by beating the light leaving the nonlinear optical medium with light from a local oscillator. A model for the loss in the detection apparatus is introduced. The squeezed-vacuum technique is introduced finally as a means of enhancing the interference fringes displaying the distinguishable quantum state.

  12. 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.

  13. Longitudinal MRI contrast enhanced monitoring of early tumour development with manganese chloride (MnCl2) and superparamagnetic iron oxide nanoparticles (SPIOs) in a CT1258 based in vivo model of prostate cancer

    PubMed Central

    2012-01-01

    Background Cell lines represent a key tool in cancer research allowing the generation of neoplasias which resemble initial tumours in in-vivo animal models. The characterisation of early tumour development is of major interest in order to evaluate the efficacy of therapeutic agents. Magnetic resonance imaging (MRI) based in-vivo characterisation allows visualisation and characterisation of tumour development in early stages prior to manual palpation. Contrast agents for MRI such as superparamagnetic iron oxide nanoparticles (SPIOs) and manganese chloride (MnCl2) represent powerful tools for the in-vivo characterisation of early stage tumours. In this experimental study, we labelled prostate cancer cells with MnCl2 or SPIOs in vitro and used 1?T MRI for tracing labelled cells in-vitro and 7?T MRI for tracking in an in-vivo animal model. Methods Labelling of prostate cancer cells CT1258 was established in-vitro with MnCl2 and SPIOs. In-vitro detection of labelled cells in an agar phantom was carried out through 1?T MRI while in-vivo detection was performed using 7?T MRI after subcutaneous (s.c.) injection of labelled cells into NOD-Scid mice (n?=?20). The animals were scanned in regular intervals until euthanization. The respective tumour volumes were analysed and corresponding tumour masses were subjected to histologic examination. Results MnCl2in-vitro labelling resulted in no significant metabolic effects on proliferation and cell vitality. In-vitro detection-limit accounted 105 cells for MnCl2 as well as for SPIOs labelling. In-vivo 7?T MRI scans allowed detection of 103 and 104 cells. In-vivo MnCl2 labelled cells were detectable from days 4–16 while SPIO labelling allowed detection until 4?days after s.c. injection. MnCl2 labelled cells were highly tumourigenic in NOD-Scid mice and the tumour volume development was characterised in a time dependent manner. The amount of injected cells correlated with tumour size development and disease progression. Histological analysis of the induced tumour masses demonstrated characteristic morphologies of prostate adenocarcinoma. Conclusions To the best of our knowledge, this is the first study reporting direct in-vitro MnCl2 labelling and 7?T based in-vivo MRI tracing of cancer cells in a model of prostate cancer. MnCl2 labelling was found to be suitable for in-vivo tracing allowing long detection periods. The labelled cells kept their highly tumourigenic potential in-vivo. Tumour volume development was visualised prior to manual palpation allowing tumour characterisation in early stages of the disease. PMID:22784304

  14. Challenges for Molecular Neuroimaging with MRI

    PubMed Central

    Lelyveld, Victor S.; Atanasijevic, Tatjana; Jasanoff, Alan

    2010-01-01

    Magnetic resonance (MRI)-based molecular imaging methods are beginning to have impact in neuroscience. A growing number of molecular imaging agents have been synthesized and tested in vitro, but so far relatively few have been validated in the brains of live animals. Here, we discuss key challenges associated with expanding the repertoire of successful molecular neuroimaging approaches. The difficulty of delivering agents past the blood-brain barrier (BBB) is a particular obstacle to molecular imaging in the central nervous system. We review established and emerging techniques for trans-BBB delivery, including intracranial infusion, BBB disruption, and transporter-related methods. Improving the sensitivity with which MRI-based molecular agents can be detected is a second major challenge. Better sensitivity would in turn reduce the requirements for delivery and alleviate potential side effects. We discuss recent efforts to enhance relaxivity of conventional longitudinal relaxation time (T1) and transverse relaxation time (T2) MRI contrast agents, as well as strategies that involve amplifying molecular signals or reducing endogenous background influences. With ongoing refinement of imaging approaches and brain delivery methods, MRI-based techniques for molecular-level neuroscientific investigation will fall increasingly within reach. PMID:20808721

  15. MRI - Nobel Prize Educational Game

    NSDL National Science Digital Library

    2009-01-01

    The MRI educational game is based on the 2003 Nobel Prize in Physiology or Medicine, which was awarded for discoveries concerning MRI - magnetic resonance imaging. A technique making it possible to get images of soft tissue inside the body.

  16. Pitfalls in fMRI

    Microsoft Academic Search

    Sven Haller; Andreas J. Bartsch

    2009-01-01

    Several different techniques allow a functional assessment of neuronal activations by magnetic resonance imaging (fMRI). The\\u000a by far most influential fMRI technique is based on a local T2*-sensitive hemodynamic response to neuronal activation, also\\u000a known as the blood oxygenation level dependent or BOLD effect. Consequently, the term ‘fMRI’ is often used synonymously with\\u000a BOLD imaging. Because interpretations of fMRI brain

  17. Advances in pediatric body MRI.

    PubMed

    Vasanawala, Shreyas S; Lustig, Michael

    2011-09-01

    MRI offers an alternative to CT, and thus is central to an ALARA strategy. However, long exam times, limited magnet availability, and motion artifacts are barriers to expanded use of MRI. This article reviews developments in pediatric body MRI that might reduce these barriers: high field systems, acceleration, navigation and newer contrast agents. PMID:21847737

  18. Functional MRI-based lie detection: scientific and societal challenges.

    PubMed

    Farah, Martha J; Hutchinson, J Benjamin; Phelps, Elizabeth A; Wagner, Anthony D

    2014-02-01

    Functional MRI (fMRI)-based lie detection has been marketed as a tool for enhancing personnel selection, strengthening national security and protecting personal reputations, and at least three US courts have been asked to admit the results of lie detection scans as evidence during trials. How well does fMRI-based lie detection perform, and how should the courts, and society more generally, respond? Here, we address various questions — some of which are based on a meta-analysis of published studies — concerning the scientific state of the art in fMRI-based lie detection and its legal status, and discuss broader ethical and societal implications. We close with three general policy recommendations. PMID:24588019

  19. Frontoparietal Activation Distinguishes Face and Space from Artifact Concepts

    PubMed Central

    Chen, Chi-Hua; Zeki, Semir

    2012-01-01

    Empirical and theoretical studies suggest that human knowledge is partly based on innate concepts that are experience-independent. We can, therefore, consider concepts underlying our knowledge as being broadly divided into inherited and acquired ones. Using fMRI, we studied the brain reaction in 20 subjects to violation of face, space (inherited), and artifact (acquired) concepts by presenting them with deformed faces, impossible figures (i.e., impossible chairs), and deformed planes, respectively, as well as their normal counterparts. Violation of the inherited concepts of face and space led to significant activation in frontoparietal cortex, whereas artifacts did not, thus distinguishing neurologically between the two categories. Participants were further exposed to these deformities daily for 1 month to test the supposition that inherited concepts are not modifiable, hence that prolonged exposure would not change the brain circuits that are engaged when viewing them. Consistent with this supposition, our results showed no significant change in activation for both categories, suggesting that such concepts are stable at the neural level at least within a time frame of 1 month. Finally, we investigated the regions of the brain that are critical for object representation. Our results show distinct and overlapping areas in the ventral visual cortex for all three categories, with faces activating the ventral visual cortex inferiorly, especially centered on right fusiform gyrus, and chairs and planes activating more diffuse regions, overlapping with the superior part of face region and mainly located in middle occipital cortex and parietal areas. PMID:21254806

  20. MRI characterization of inflammatory myofibroblastic tumors in the maxillofacial region

    PubMed Central

    Li, Hui; Wang, De-Ling; Liu, Xue-Wen; Geng, Zhi-Jun; Xie, Chuan-Miao

    2014-01-01

    PURPOSE We aimed to investigate the magnetic resonance imaging (MRI) appearance of inflammatory myofibroblastic tumors (IMTs) in the maxillofacial region in order to improve diagnostic quality and resection efficacy. MATERIALS AND METHODS Ten cases of pathologically identified IMTs were analyzed by MRI. The MRI features were examined, including tumor location, tumor shape, tumor margins, and involvement of the surrounding tissues. RESULTS Of ten masses investigated in this study, eight masses were irregular neoplasms with unclear margins and two masses, in the parotid gland, were regular neoplasms with clear margins. Precontrast T1-weighted images of all ten masses exhibited isointense signals compared to the adjacent tissue, while contrast-enhanced T1-weighted images showed strong enhancement. Six masses were hypointense and four masses were slightly hyperintense in T2-weighted images. Involvement of the adjacent structures was observed in eight of ten cases. Meanwhile, two patients experienced intracranial involvement. CONCLUSION IMTs are rare tumors in the maxillofacial region, displaying a number of distinct MRI characteristics. Most importantly, they display low T2 signal intensity and strong enhancement, and they frequently invade surrounding structures. Thus, MRI can improve the accuracy of IMT diagnoses and provide critical information for surgical planning. PMID:24808436

  1. LOCC distinguishability of unilaterally transformable quantum states

    E-print Network

    Bandyopadhyay, Somshubhro; Kar, Guruprasad

    2011-01-01

    We consider the question of perfect local distinguishability of mutually orthogonal bipartite quantum states with the property that every state can be specified by a unitary operator acting on the local Hilbert space of Bob. We show that if the states can be exactly discriminated by one-way LOCC where Alice goes first, then the unitary operators can also be perfectly distinguished by an orthogonal measurement on Bob's Hilbert space. This necessary condition also holds for two-way LOCC protocols if Alice goes first provided Alice's system has dimension two. We then give examples of sets of $N\\leq d$ maximally entangled states in $d\\otimes d$ for $d=4,5,6$ that are not perfectly distinguishable by one-way LOCC. We conjecture that these states cannot be perfectly discriminated by two-way LOCC.

  2. LOCC distinguishability of unilaterally transformable quantum states

    E-print Network

    Somshubhro Bandyopadhyay; Sibasish Ghosh; Guruprasad Kar

    2011-11-04

    We consider the question of perfect local distinguishability of mutually orthogonal bipartite quantum states, with the property that every state can be specified by a unitary operator acting on the local Hilbert space of Bob. We show that if the states can be exactly discriminated by one-way LOCC where Alice goes first, then the unitary operators can also be perfectly distinguished by an orthogonal measurement on Bob's Hilbert space. We give examples of sets of N<=d maximally entangled states in $d \\otimes d $ for d=4,5,6 that are not perfectly distinguishable by one-way LOCC. Interestingly for d=5,6 our examples consist of four and five states respectively. We conjecture that these states cannot be perfectly discriminated by two-way LOCC.

  3. Expanding the principle of local distinguishability

    E-print Network

    Claudio Carmeli; Teiko Heinosaari; Jussi Schultz; Alessandro Toigo

    2015-04-07

    The principle of local distinguishability states that an arbitrary physical state of a bipartite system can be determined by the combined statistics of local measurements performed on the subsystems. A necessary and sufficient requirement for the local measurements is that each one must be able to distinguish between all pairs of states of the respective subsystems. We show that if the task is changed into the determination of an arbitrary bipartite pure state, then at least in certain cases it is possible to restrict to local measurements which can distintinguish all pure states but not all states. This surprising fact gives evidence that the principle of local distinguishability may be expanded beyond its usual applicability.

  4. Hornbills can distinguish between primate alarm calls.

    PubMed Central

    Rainey, Hugo J.; Zuberbühler, Klaus; Slater, Peter J. B.

    2004-01-01

    Some mammals distinguish between and respond appropriately to the alarm calls of other mammal and bird species. However, the ability of birds to distinguish between mammal alarm calls has not been investigated. Diana monkeys (Cercopithecus diana) produce different alarm calls to two predators: crowned eagles (Stephanoaetus coronatus) and leopards (Panthera pardus). Yellow-casqued hornbills (Ceratogymna elata) are vulnerable to predation by crowned eagles but are not preyed on by leopards and might therefore be expected to respond to the Diana monkey eagle alarm call but not to the leopard alarm call. We compared responses of hornbills to playback of eagle shrieks, leopard growls, Diana monkey eagle alarm calls and Diana monkey leopard alarm calls and found that they distinguished appropriately between the two predator vocalizations as well as between the two Diana monkey alarm calls. We discuss possible mechanisms leading to these responses. PMID:15209110

  5. MRI in cerebellar hypoplasia

    Microsoft Academic Search

    N. deSouza; R. Chaudhuri; J. Bingham; T. Cox

    1994-01-01

    Cerebellar hypoplasia may present with a wide variety of neurological and systemic features, ranging from aplasia causing neonatal death to mild hypoplasia in an asymptomatic adult. MRI clearly documents the size of the cerebellum and any associated abnormalities. We describe 7 cases of cerebellar hypoplasia of varying aetiology-3 inherited, 2 associated with spinal dysraphism, 1 with Joubert's syndrome and 1

  6. MRI driven magnetic microswimmers

    PubMed Central

    Jakab, Péter; Székely, Gábor; 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

  7. DISTINGUISHED INNOVATION AND IMPACT AWARD 2014 Basic Information

    E-print Network

    Tipple, Brett

    DISTINGUISHED INNOVATION AND IMPACT AWARD 2014 Basic Information The Distinguished Innovation and Impact Award (DIIA) recognizes outstanding innovators whose accomplishments as faculty members distinguished themselves and the University through entrepreneurial activities that have resulted in innovations

  8. DISTINGUISHED INNOVATION AND IMPACT AWARD 2015 Basic Information

    E-print Network

    Tipple, Brett

    DISTINGUISHED INNOVATION AND IMPACT AWARD 2015 Basic Information The Distinguished Innovation and Impact Award (DIIA) recognizes outstanding innovators whose accomplishments as faculty members distinguished themselves and the University through entrepreneurial activities that have resulted in innovations

  9. 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

  10. Beyond Benford's Law: Distinguishing Noise from Chaos.

    PubMed

    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

  11. 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…

  12. Can medial temporal lobe regions distinguish true from false? An event-related functional MRI study

    E-print Network

    Wagner, Anthony

    , there is evidence that MTL is sensitive to the sensory (percep- tual) properties of recovered episodic information. For example, a positron emission tomography (PET) study found that MTL activity during object recognition, there is evidence that MTL recovers semantic (conceptual) but not sensory properties of episodic information

  13. MRI findings of a middle ear cholesteatoma in a dog.

    PubMed

    Harran, Nathaniel X; Bradley, Kate J; Hetzel, Natasha; Bowlt, Kelly L; Day, Michael J; Barr, Frances

    2012-01-01

    This article describes the MRI features of a middle ear cholesteatoma in an 8 yr old flat-coated retriever. Physical examination revealed pain on opening the jaw, and otoscopic examination showed tympanic membrane rupture associated with hyperplastic tissue at the entrance of the middle ear. Standard MRI sequences allowed for the identification of a severely expanded bulla containing material that was isointense to brain tissue on T1-weighted images and of mixed intensity on T2-weighted and fluid-attenuated inversion recovery sequences. No postcontrast enhancement of the content was present, but the lining of the bulla was partially enhanced. The images allowed evaluation of the surgical margins and the secondary changes due to the expansion of the mass. Surgery was performed and histopathology confirmed the presumptive diagnosis of cholesteatoma. In the present case, MRI appeared to serve as a good alternative to computed tomography for the diagnosis of cholesteatoma. PMID:22843826

  14. Autonomic Nervous System Activity Distinguishes among Emotions

    Microsoft Academic Search

    Paul Ekman; Robert W. Levenson; Wallace V. Friesen

    1983-01-01

    Emotion-specific activity in the autonomic nervous system was generated by constructing facial prototypes of emotion muscle by muscle and by reliving past emotional experiences. The autonomic activity produced distinguished not only between positive and negative emotions, but also among negative emotions. This finding challenges emotion theories that have proposed autonomic activity to be undifferentiated or that have failed to address

  15. Fall 2011 -Distinguished Lecture Program Semantic Web

    E-print Network

    Mayfield, John

    Fall 2011 - Distinguished Lecture Program Semantic Web: State of the Art Semantic Web: State record lists over 160 publications in such diverse areas as semantic web, neural-symbolic integration-in-chief of the IOS Press journal "Semantic Web" and the IOS Press book series "Studies on the Semantic Web". He

  16. Awards for Distinguished Professional Contributions: 1980

    Microsoft Academic Search

    CARL R. ROGERS; DAVID WECHSLER; NOBLE H. KELLEY; GEORGE W. ALBEE; JOHN C. FLANAGAN; DAVID SHAKOW; GEORGE KATONA; ARTHUR L; DOUGLAS W. BRAY; ZYGMUNT A. PIOTROWSKI; LEONARD D. ERON; NICHOLAS HOBBS; HERBERT DORKEN; SOL Li; WILLIAM A. HUNT

    Recognizing the diversity of roles and activities in which many professional psychologists are engaged, beginning in 1979 Professional Awards have been presented to three individual members of the Association whose distinguished contributions have served to advance psychology as a profession in the area of knowledge, in public service, and in professional practice. The 1980 recipients, honored at the annual convention

  17. Awards for Distinguished Professional Contributions: 1982

    Microsoft Academic Search

    Carl B. Rogers; David Wechsler; Noble H. Kelley; George W. Albee; John C. Ranagan; David Shakow; Arthur L. Benton; Sol L. Garfield; William A. Hunt; Douglas W. Bray; Leonard D. Eron; Zygmunt A. Piotrowski; Jack I. Bardon; Carl Eisdorfer; Jane W. Kessler; Asher R. Pacht; Carolyn R. Payton; Roy Schafer; Milton Theaman

    Recognizing the diversity of roles and activities in which many professional psychologists are engaged, beginning in 1979 Professional Awards have been presented to three individual members of the Association whose distinguished contributions have served to advance psychology as a profession in the area of knowledge, public service, and professional practice. The 1982 recipients, honored at the annual convention in Washington,

  18. Distinguishing between excessive daytime sleepiness and fatigue

    Microsoft Academic Search

    Wilfred R Pigeon; Michael J Sateia; Robert J Ferguson

    2003-01-01

    Introduction: Excessive daytime sleepiness (EDS) and fatigue occur in high percentages in the general population. They are common complaints in primary care and in specialty medicine. Although they may represent distinct or overlapping phenomena, the general medical literature does not normally distinguish between EDS and fatigue. Despite their prevalence, both EDS and fatigue are identified and treated in a relatively

  19. When Plans Distinguish Bayes Nets Alex Dekhtyar

    E-print Network

    Dekhtyar, Alexander

    When Plans Distinguish Bayes Nets Alex Dekhtyar dekhtyar@cs.uky.edu Department of Computer Science distributions result in different plans or significantly different plan success for Bayes nets. Subarea: belief networks. Keywords: Bayes nets, information integration, complexity, stochastic planning. 1 Introduction

  20. 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"…

  1. Repetitive sequence environment distinguishes housekeeping genes

    PubMed Central

    Eller, C. Daniel; Regelson, Moira; Merriman, Barry; Nelson, Stan; Horvath, Steve; Marahrens, York

    2007-01-01

    Housekeeping genes are expressed across a wide variety of tissues. Since repetitive sequences have been reported to influence the expression of individual genes, we employed a novel approach to determine whether housekeeping genes can be distinguished from tissue-specific genes their repetitive sequence context. We show that Alu elements are more highly concentrated around housekeeping genes while various longer (>400-bp) repetitive sequences ("repeats"), including Long Interspersed Nuclear Element 1 (LINE-1) elements, are excluded from these regions. We further show that isochore membership does not distinguish housekeeping genes from tissue-specific genes and that repetitive sequence environment distinguishes housekeeping genes from tissue-specific genes in every isochore. The distinct repetitive sequence environment, in combination with other previously published sequence properties of housekeeping genes, were used to develop a method of predicting housekeeping genes on the basis of DNA sequence alone. Using expression across tissue types as a measure of success, we demonstrate that repetitive sequence environment is by far the most important sequence feature identified to date for distinguishing housekeeping genes. PMID:17141428

  2. Distinguishing Answers in Conceptual Graph Knowledge Bases

    E-print Network

    Paris-Sud XI, Université de

    Distinguishing Answers in Conceptual Graph Knowledge Bases Nicolas Moreau, Michel Lecl to be computed. For this case, there are two kinds of answer graphs: answers as subgraphs of the knowledge base a specific pattern of knowledge. The suppression of redundant answers only by comparing answer graphs

  3. Soil Properties That Distinguish Ecological Sites

    E-print Network

    that determines soil water amounts. Soil properties are features of a soil: · e.g. soil texture, depth #12Soil Properties That Distinguish Ecological Sites Mike Duniway USGS-Southwest Biological Science Properties · Within a climatic zone (e.g. MLRA), differentiation of ecological sites based on soil

  4. Distinguishing Causal Interactions in Neural Populations

    Microsoft Academic Search

    Anil K. Seth; Gerald M. Edelman

    2007-01-01

    We describe a theoretical network analysis that can distinguish statistically causal interactions in population neural activity leading to a specific output. We introduce the concept of a causal core to refer to the set of neuronal interactions that are causally significant for the output, as assessed by Granger causality. Because our approach requires extensive knowledge of neuronal connectivity and dynamics,

  5. Distinguishing Attributes for the Operationally Responsive Space

    E-print Network

    de Weck, Olivier L.

    in this presentation are those of the author and do not reflect the official policy or position of the United States analytic due diligence." (Mr. Gil Klinger, Former Director of Space Policy, U.S. National Security CouncilDistinguishing Attributes for the Operationally Responsive Space Paradigm Matthew G. Richards

  6. 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…

  7. BERKELEY CATALYSIS CENTER Distinguished Lecture Series

    E-print Network

    Iglesia, Enrique

    BERKELEY CATALYSIS CENTER Distinguished Lecture Series Nov 13, 2003 The McCollum Room 775-A Tan vehicles on the road today utilize closed-loop, stoichiometric air-fuel control and a three-way catalyst NOx emissions under fuel-lean condit ions, where the best fuel economy is realized. Serious research

  8. Exophytic benign tumors of the liver: appearance on MRI

    Microsoft Academic Search

    Till R. Bader; Larissa Braga; Richard C. Semelka

    2001-01-01

    The purpose of our study was to determine the MR imaging appearance of exophytic benign liver tumors on precontrast and postgadolinium images. We reviewed our 9.5 year experience with MRI of the liver with dynamic gadolinium enhanced imaging to identify four patients with five histologically proven exophytic benign liver tumors. The histological diagnoses were cavernous hemangioma (2), focal nodular hyperplasia

  9. Prostate cancer magnetic resonance imaging (MRI): multidisciplinary standpoint

    PubMed Central

    Li, Liang; Feng, Zhaoyan; Hu, Zhiquan; Wang, Guoping; Yuan, Xianglin; Wang, He; Hu, Daoyu

    2013-01-01

    Prostate cancer is the most common cancer diagnosed in men and a leading cause of death. Accurate assessment is a prerequisite for optimal clinical management and therapy selection of prostate cancer. There are several parameters and nomograms to differentiate between patients with clinically insignificant disease and patients in need of treatment. Magnetic resonance imaging (MRI) is a technique which provides more detailed anatomical images due to high spatial resolution, superior contrast resolution, and multiplanar capability. State-of-the-art MRI techniques, such as diffusion weighted imaging (DWI), MR spectroscopic imaging (MRSI), dynamic contrast enhanced MRI (DCE-MRI), improve interpretation of prostate cancer imaging. In this article, we review the major role of MRI in the advanced management of prostate cancer to noninvasively improve tumor staging, biologic potential, treatment planning, therapy response, local recurrence, and to guide target biopsy for clinical suspected cancer with previous negative biopsy. Finally, future challenges and opportunities in prostate cancer management in the area of functional MRI are discussed as well. PMID:23630657

  10. Cerebral blood volume MRI with intravascular superparamagnetic iron oxide nanoparticles.

    PubMed

    Kim, Seong-Gi; Harel, Noam; Jin, Tao; Kim, Tae; Lee, Phil; Zhao, Fuqiang

    2013-08-01

    The cerebral blood volume (CBV) is a crucial physiological indicator of tissue viability and vascular reactivity. Thus, noninvasive CBV mapping has been of great interest. For this, ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles, including monocrystalline iron oxide nanoparticles, can be used as long-half-life, intravascular susceptibility agents of CBV MRI measurements. Moreover, CBV-weighted functional MRI (fMRI) with USPIO nanoparticles provides enhanced sensitivity, reduced large vessel contribution and improved spatial specificity relative to conventional blood oxygenation level-dependent fMRI, and measures a single physiological parameter that is easily interpretable. We review the physiochemical and magnetic properties, and pharmacokinetics, of USPIO nanoparticles in brief. We then extensively discuss quantifications of baseline CBV, vessel size index and functional CBV change. We also provide reviews of dose-dependent sensitivity, vascular filter function, specificity, characteristics and impulse response function of CBV fMRI. Examples of CBV fMRI specificity at the laminar and columnar resolution are provided. Finally, we briefly review the application of CBV measurements to functional and pharmacological studies in animals. Overall, the use of USPIO nanoparticles can determine baseline CBV and its changes induced by functional activity and pharmacological interventions. PMID:23208650

  11. Occupational exposure in MRI

    PubMed Central

    Mcrobbie, D W

    2012-01-01

    This article reviews occupational exposure in clinical MRI; it specifically considers units of exposure, basic physical interactions, health effects, guideline limits, dosimetry, results of exposure surveys, calculation of induced fields and the status of the European Physical Agents Directive. Electromagnetic field exposure in MRI from the static field B0, imaging gradients and radiofrequency transmission fields induces electric fields and currents in tissue, which are responsible for various acute sensory effects. The underlying theory and its application to the formulation of incident and induced field limits are presented. The recent International Commission on Non-Ionizing Radiation Protection (ICNIRP) Bundesministerium für Arbeit und Soziales and Institute of Electrical and Electronics Engineers limits for incident field exposure are interpreted in a manner applicable to MRI. Field measurements show that exposure from movement within the B0 fringe field can exceed ICNIRP reference levels within 0.5 m of the bore entrance. Rate of change of field dB/dt from the imaging gradients is unlikely to exceed the new limits, although incident field limits can be exceeded for radiofrequency (RF) exposure within 0.2–0.5 m of the bore entrance. Dosimetric surveys of routine clinical practice show that staff are exposed to peak values of 42±24% of B0, with time-averaged exposures of 5.2±2.8 mT for magnets in the range 0.6–4 T. Exposure to time-varying fields arising from movement within the B0 fringe resulted in peak dB/dt of approximately 2 T s?1. Modelling of induced electric fields from the imaging gradients shows that ICNIRP-induced field limits are unlikely to be exceeded in most situations; however, movement through the static field may still present a problem. The likely application of the limits is discussed with respect to the reformulation of the European Union (EU) directive and its possible implications for MRI. PMID:22457400

  12. Molecular MRI enables early and sensitive detection of brain metastases.

    PubMed

    Serres, Sébastien; Soto, Manuel Sarmiento; Hamilton, Alastair; McAteer, Martina A; Carbonell, W Shawn; Robson, Matthew D; Ansorge, Olaf; Khrapitchev, Alexandre; Bristow, Claire; Balathasan, Lukxmi; Weissensteiner, Thomas; Anthony, Daniel C; Choudhury, Robin P; Muschel, Ruth J; Sibson, Nicola R

    2012-04-24

    Metastasis to the brain is a leading cause of cancer mortality. The current diagnostic method of gadolinium-enhanced MRI is sensitive only to larger tumors, when therapeutic options are limited. Earlier detection of brain metastases is critical for improved treatment. We have developed a targeted MRI contrast agent based on microparticles of iron oxide that enables imaging of endothelial vascular cell adhesion molecule-1 (VCAM-1). Our objectives here were to determine whether VCAM-1 is up-regulated on vessels associated with brain metastases, and if so, whether VCAM-1-targeted MRI enables early detection of these tumors. Early up-regulation of cerebrovascular VCAM-1 expression was evident on tumor-associated vessels in two separate murine models of brain metastasis. Metastases were detectable in vivo using VCAM-1-targeted MRI 5 d after induction (<1,000 cells). At clinical imaging resolutions, this finding is likely to translate to detection at tumor volumes two to three orders of magnitude smaller (0.3-3 × 10(5) cells) than those volumes detectable clinically (10(7)-10(8) cells). VCAM-1 expression detected by MRI increased significantly (P < 0.0001) with tumor progression, and tumors showed no gadolinium enhancement. Importantly, expression of VCAM-1 was shown in human brain tissue containing both established metastases and micrometastases. Translation of this approach to the clinic could increase therapeutic options and change clinical management in a substantial number of cancer patients. PMID:22451897

  13. MRI of Cartilage: Standard Techniques

    Microsoft Academic Search

    Thomas M. Link

    \\u000a Magnetic resonance imaging (MRI) is the only imaging technique that allows direct visualization of cartilage with sufficient\\u000a contrast. However, cartilage imaging is challenging and MRI needs to be tailored to best visualize cartilage morphology, which\\u000a includes using scanners with adequate field strength, coils which allow high spatial resolution imaging, and optimized imaging\\u000a sequences. Also MRI should not only allow to

  14. MRI in recurrent nasopharyngeal carcinoma

    Microsoft Academic Search

    S. H. Ng; J. T. C. Chang; S. F. Ko; Y. L. Wan; L. M. Tang; W. C. Chen

    1999-01-01

    In this study, we retrospectively reviewed the MRI features of recurrent nasopharyngeal carcinoma (NPC) in 72 patients who\\u000a underwent MRI before and after gadolinium injection. Recurrent NPC exhibited a high degree of regional spread and a variety\\u000a of signal intensities and contours. MRI showed a nasopharyngeal mass in 50 patients (69.4 %); other sites of involvement included\\u000a the parapharyngeal space

  15. Uterine sarcomas: clinical presentation and MRI features

    PubMed Central

    Santos, Pedro; Cunha, Teresa Margarida

    2015-01-01

    Uterine sarcomas are a rare heterogeneous group of tumors of mesenchymal origin, accounting for approximately 8% of uterine malignancies. They comprise leiomyosarcoma, endometrial stromal sarcoma, undifferentiated endometrial sarcoma, and adenosarcoma. Compared with the more common endometrial carcinomas, uterine sarcomas behave more aggressively and are associated with a poorer prognosis. Due to their distinct clinical and biological behavior, the International Federation of Gynecology and Obstetrics introduced a new staging system for uterine sarcomas in 2009, categorizing uterine carcinosarcoma as a variant of endometrial carcinoma, rather than a pure sarcoma. Magnetic resonance imaging (MRI) has a developing role in the assessment of these malignancies. Features such as tumor localization, irregular or nodular margins, necrosis, rapid growth, intense contrast enhancement, and restriction at diffusion-weighted imaging can suggest the diagnosis and help differentiate from more common leiomyomas and endometrial carcinoma. MRI is therefore extremely useful in preoperative detection and staging and, consequently, in determination of appropriate management. This pictorial review aims to discuss the clinical features of uterine sarcomas, as well as their most common appearances and distinct characteristics in MRI. PMID:25347940

  16. 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.

  17. Duality of Quantum Coherence and Path Distinguishability

    E-print Network

    Manabendra Nath Bera; Tabish Qureshi; Mohd Asad Siddiqui; Arun Kumar Pati

    2015-03-10

    We derive a generalized wave-particle duality relation for arbitrary dimensional multi-path quantum interference phenomena. Beyond the traditional signature of the wave nature of a quantum system, i.e., the fringe visibility, we introduce a novel quantifier as the normalized quantum coherence, recently defined in the frame-work 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 multi-path 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-know complementarity relation. The new duality relation continues to hold in the case where mixedness is introduced due to possible decoherence effects.

  18. Distinguishing juvenile homicide from violent juvenile offending.

    PubMed

    DiCataldo, Frank; Everett, Meghan

    2008-04-01

    Juvenile homicide is a social problem that has remained a central focus within juvenile justice research in recent years. The term juvenile murderer describes a legal category, but it is purported to have significant scientific meaning. Research has attempted to conceptualize adolescent murderers as a clinical category that can be reliably distinguished from their nonhomicidal counterparts. This study examined 33 adolescents adjudicated delinquent or awaiting trial for murder and 38 adolescents who committed violent, nonhomicidal offenses to determine whether the two groups differed significantly on family history, early development, delinquency history, mental health, and weapon possession variables. The nonhomicide group proved more problematic on many of these measures. Two key factors did distinguish the homicide group: These adolescents endorsed the greater availability of guns and substance abuse at the time of their commitment offenses. The significance of this finding is discussed, and the implications for risk management and policy are reviewed. PMID:17671097

  19. Distinguishing quantum channels via magic squares game

    E-print Network

    M. Ramzan; M. K. Khan

    2010-01-02

    We study the effect of quantum memory in magic squares game when played in quantum domain. We consider different noisy quantum channels and analyze their influence on the magic squares quantum pseudo-telepathy game. We show that the probability of success can be used to distinguish the quantum channels. It is seen that the mean success probability decreases with increase of quantum noise. Where as the mean success probability increases with increase of quantum memory. It is also seen that the behaviour of amplitude damping and phase damping channels is similar. On the other hand, the behaviour of depolarizing channel is similar to the flipping channels. Therefore, the probability of success of the game can be used to distinguish the quantum channels.

  20. Distinguishing quantum channels via magic squares game

    E-print Network

    Ramzan, M

    2010-01-01

    We study the effect of quantum memory in magic squares game when played in quantum domain. We consider different noisy quantum channels and analyze their influence on the magic squares quantum pseudo-telepathy game. We show that the probability of success can be used to distinguish the quantum channels. It is seen that the mean success probability decreases with increase of quantum noise. Where as the mean success probability increases with increase of quantum memory. It is also seen that the behaviour of amplitude damping and phase damping channels is similar. On the other hand, the behaviour of depolarizing channel is similar to the flipping channels. Therefore, the probability of success of the game can be used to distinguish the quantum channels.

  1. 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.

  2. MRI in neuro-Behçet's disease

    Microsoft Academic Search

    E. T. Tal?; S. Atilla; T. Keskin; T. Simonson; S. I?ik; W. T. C. Yuh

    1997-01-01

    Our purpose was to characterise specific MRI findings and to determine their value in neuro-Behet's disease. We examined\\u000a 17 patients (14 men, 3 women) with neuro-Behet's disease using T1- and T2-weighted spin-echo images and contrast-enhanced\\u000a images at 0.5 T. There were 13 patients (76.5 %) who had single or multiple lesions. Most of these were in the basal ganglia,\\u000a brain

  3. Distinguishing Regulatory DNA From Neutral Sites

    Microsoft Academic Search

    Laura Elnitski; Ross C. Hardison; Jia Li; Shan Yang; Diana Kolbe; Pallavi Eswara; Michael J. O'Connor; Scott Schwartz; Webb Miller; Francesca Chiaromonte

    2003-01-01

    We explore several computational approaches to analyzing interspecies genomic sequence alignments, aiming to distinguish regulatory regions from neutrally evolving DNA. Human-mouse genomic alignments were collected for three sets of human regions: (1) experimentally defined gene regulatory regions, (2) well-characterized exons (coding sequences, as a positive control), and (3) interspersed repeats thought to have inserted before the human-mouse split (a good

  4. Efficacy and safety of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. Multicenter phase III clinical trials. Efficacy of early imaging.

    PubMed

    Federle, M; Chezmar, J; Rubin, D L; Weinreb, J; Freeny, P; Schmiedl, U P; Brown, J J; Borrello, J A; Lee, J K; Semelka, R C; Mattrey, R; Dachman, A H; Saini, S; Harms, S E; Mitchell, D G; Anderson, M W; Halford, H H; Bennett, W F; Young, S W; Rifkin, M; Gay, S B; Ballerini, R; Sherwin, P F; Robison, R O

    2000-11-01

    The efficacy of contrast-enhanced magnetic resonance imaging (MRI) for detecting and characterizing, or excluding, hepatic masses was assessed in 404 patients, following the intravenous administration of mangafodipir trisodium (MnDPDP) injection, a hepatic MRI contrast agent. An initial contrast-enhanced computed tomography (CT) examination was followed by unenhanced MRI, injection of MnDPDP (5 micromol/kg IV), and enhanced MRI at 15 minutes post injection. Agreement of the radiologic diagnoses with the patients' final diagnoses was higher for enhanced MRI and for the combined unenhanced and enhanced MRI evaluations than for unenhanced MRI alone or enhanced CT using the clinical diagnosis as the gold standard. Mangafodipir-enhanced MRI uniquely provided additional diagnostic information in 48% of the patients, and patient management was consequently altered in 6% of the patients. MnDPDP-enhanced MRI was comparable or superior to unenhanced MRI and enhanced CT for the detection, classification, and diagnosis of focal liver lesions in patients with known or suspected focal liver disease. PMID:11050638

  5. 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

  6. 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

  7. Evaluation of primary adnexal masses by 3T MRI: categorization with conventional MR imaging and diffusion-weighted imaging

    PubMed Central

    2012-01-01

    Background To investigate the 3.0-Tesla (3 T) magnetic resonance imaging (MRI) characteristics of primary adnexal lesions for discriminating benign from malignant lesions. Methods One hundred thirty-nine patients with pathologically proven primary adnexal masses referred for 3 T MRI assessment preoperatively were included. Baseline characteristics, components, and conventional MRI and diffusion-weighted imaging (DWI-MRI) signals were recorded and compared. Results There were 22 ovarian cysts, 33 endometriomas, 43 benign tumors and 42 malignant tumors. When ovarian cyst and endometrioma were excluded, there were no significant differences in patients’ age between benign and malignant tumor (P = 0.235). There were no significant differences (P = 0.606) in the conventional MRI signals and significant difference (P = 0.008) in DWI-MRI signal between the non-malignant and malignant lesions. There was a significant difference (P = 0.000) in the apparent diffusion coefficient values (ADCs) between the non-malignant and malignant lesions. Conclusions 3 T MRI categorized the characteristics of primary adnexal lesions. Conventional MRI signals were not useful for characterizing between benign and malignant lesions. DWI-MRI and ADCs were helpful for distinguishing malignant from benign ovarian lesions. PMID:23148860

  8. Hyperpolarized Xenon for NMR and MRI Applications

    PubMed Central

    Witte, Christopher; Kunth, Martin; Döpfert, Jörg; Rossella, Federica; Schröder, Leif

    2012-01-01

    Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) suffer from intrinsic low sensitivity because even strong external magnetic fields of ~10 T generate only a small detectable net-magnetization of the sample at room temperature 1. Hence, most NMR and MRI applications rely on the detection of molecules at relative high concentration (e.g., water for imaging of biological tissue) or require excessive acquisition times. This limits our ability to exploit the very useful molecular specificity of NMR signals for many biochemical and medical applications. However, novel approaches have emerged in the past few years: Manipulation of the detected spin species prior to detection inside the NMR/MRI magnet can dramatically increase the magnetization and therefore allows detection of molecules at much lower concentration 2. Here, we present a method for polarization of a xenon gas mixture (2-5% Xe, 10% N2, He balance) in a compact setup with a ca. 16000-fold signal enhancement. Modern line-narrowed diode lasers allow efficient polarization 7 and immediate use of gas mixture even if the noble gas is not separated from the other components. The SEOP apparatus is explained and determination of the achieved spin polarization is demonstrated for performance control of the method. The hyperpolarized gas can be used for void space imaging, including gas flow imaging or diffusion studies at the interfaces with other materials 8,9. Moreover, the Xe NMR signal is extremely sensitive to its molecular environment 6. This enables the option to use it as an NMR/MRI contrast agent when dissolved in aqueous solution with functionalized molecular hosts that temporarily trap the gas 10,11. Direct detection and high-sensitivity indirect detection of such constructs is demonstrated in both spectroscopic and imaging mode. PMID:22986346

  9. Hyperpolarized xenon for NMR and MRI applications.

    PubMed

    Witte, Christopher; Kunth, Martin; Döpfert, Jörg; Rossella, Federica; Schröder, Leif

    2012-01-01

    Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) suffer from intrinsic low sensitivity because even strong external magnetic fields of ~10 T generate only a small detectable net-magnetization of the sample at room temperature (1). Hence, most NMR and MRI applications rely on the detection of molecules at relative high concentration (e.g., water for imaging of biological tissue) or require excessive acquisition times. This limits our ability to exploit the very useful molecular specificity of NMR signals for many biochemical and medical applications. However, novel approaches have emerged in the past few years: Manipulation of the detected spin species prior to detection inside the NMR/MRI magnet can dramatically increase the magnetization and therefore allows detection of molecules at much lower concentration (2). Here, we present a method for polarization of a xenon gas mixture (2-5% Xe, 10% N2, He balance) in a compact setup with a ca. 16000-fold signal enhancement. Modern line-narrowed diode lasers allow efficient polarization (7) and immediate use of gas mixture even if the noble gas is not separated from the other components. The SEOP apparatus is explained and determination of the achieved spin polarization is demonstrated for performance control of the method. The hyperpolarized gas can be used for void space imaging, including gas flow imaging or diffusion studies at the interfaces with other materials (8,9). Moreover, the Xe NMR signal is extremely sensitive to its molecular environment (6). This enables the option to use it as an NMR/MRI contrast agent when dissolved in aqueous solution with functionalized molecular hosts that temporarily trap the gas (10,11). Direct detection and high-sensitivity indirect detection of such constructs is demonstrated in both spectroscopic and imaging mode. PMID:22986346

  10. Multiple nodular lesions in spleen associated with visceral leishmaniasis: a case report of MRI-findings.

    PubMed

    Mao, Guoqun; Yang, Guangzhao; Cheng, Yougen; Zee, Chi S; Huang, Wenmin; Ni, Weiyang; Meng, Guanmin; Chen, Zhilu

    2014-12-01

    The spleen is one of the most commonly involved organs of visceral leishmaniasis (VL). However, there were few reports about imaging findings of splenic leishmaniasis, especially regarding MRI findings. This case report describes a 45 years old male patient from Zhejiang province of southeastern China, who was admitted for persistent fever of unknown origin, with splenomegaly and multiple hypodense/low echo nodules on CT/ultrasonography (USG) studies. MRI showed multiple nodules with concentric rings in the spleen on T2-weighted imaging (T2WI), with no obvious diffusion restriction on diffusion weighted imaging (DWI), and gradual ring-like enhancement after intravenous administration of contrast medium. So MRI suggested necrotic granulomatous lesion. By reviewing the clinical history and following positive serological leishmania antibody test, the patient was finally confirmed a recent infection with VL. The patient received antimony gluconate therapy intravenously. At 4 months follow-up, the contrast-enhanced abdominal MRI showed that the size of the spleen was returned to normal and the splenic lesions were completely resolved except for reduced infarction compared with the previous MRI. This is the first case which was performed MRI examination completely. Meanwhile, it is the second case which MRI findings were reported. As for the characteristics of MRI in this case, there are several features, which are helpful for giving the diagnosis and differential diagnosis of VL. PMID:25546669

  11. RF HEATING OF MRI-ASSISTED CATHETER STEERING COILS FOR INTERVENTIONAL MRI

    PubMed Central

    Settecase, Fabio; Hetts, Steven W.; Martin, Alastair J.; Roberts, Timothy P. L.; Bernhardt, Anthony F.; Evans, Lee; Malba, Vincent; Saeed, Maythem; Arenson, Ronald L.; Kucharzyk, Walter; Wilson, Mark W.

    2010-01-01

    RATIONALE AND OBJECTIVES To assess magnetic resonance imaging (MRI) radiofrequency (RF) related heating of conductive wire coils used in magnetically steerable endovascular catheters. MATERIALS AND METHODS A 3-axis microcoil was fabricated onto a 1.8 Fr catheter tip. In vitro testing was performed in a 1.5 T MRI system using an agarose gel filled vessel phantom, a transmit/receive body RF coil and a steady state free precession (SSFP) pulse sequence, and a fluoroptic thermometry system. Temperature was measured without simulated blood flow at varying distances from magnet isocenter and varying flip angles. Additional experiments were performed with laser-lithographed single-axis microcoil-tipped microcatheters in air and in a saline bath with varied grounding of the microcoil wires. Preliminary in vivo evaluation of RF heating was performed in pigs at 1.5 T with coil-tipped catheters in various positions in the common carotid arteries with SSFP pulse sequence on and off, and under physiologic flow and zero flow conditions. RESULTS In tissue-mimicking agarose gel, RF heating resulted in a maximal temperature increase of 0.35°C after 15 minutes of imaging, 15 cm from magnet isocenter. For a single axis microcoil, maximal temperature increases were 0.73-1.91°C in air and 0.45-0.55°C in saline. In vivo, delayed contrast enhanced MRI revealed no evidence of vascular injury and histopathological sections from the common carotid arteries confirmed the lack of vascular damage. CONCLUSIONS Microcatheter tip microcoils for endovascular catheter steering in MRI experience minimal RF heating under the conditions tested. These data provide the basis for further in vivo testing of this promising technology for endovascular interventional MRI. PMID:21075019

  12. 3-5 BI-RADs Microcalcifications: Correlation between MRI and Histological Findings.

    PubMed

    Fiaschetti, Valeria; Pistolese, Chiara Adriana; Perretta, Tommaso; Cossu, Elsa; Arganini, Chiara; Salimbeni, Claudia; Scarano, Angela Lia; Arduini, Silvia; Simonetti, Giovanni

    2011-01-01

    Purpose. To evaluate the correlation between MRI and histopathological findings in patients with mammographically detected 3-5 BI-RAD (Breast Imaging Reporting And Data Systems) microcalcifications and to allow a better surgical planning. Materials and Method. 62 female Patients (age 50 ± 12) with screening detected 3-5 BI-RAD microcalcifications underwent dynamic 3 T contrast-enhanced breast MRI. After 30-day (range 24-36 days) period, 55 Patients underwent biopsy using stereotactic vacuum-assisted biopsy (VAB), 5 Patients underwent stereotactic mammographically guided biopsy, and 2 Patients underwent MRI-guided VAB. Results. Microhistology examination demonstrated 36 malignant lesions and 26 benign lesions. The analysis of MRI findings identified 8 cases of MRI BI-RADS 5, 23 cases of MRI BI-RADS 4, 11 cases of MRI BI-RADS 3, 4 cases type A and 7 cases type B, and 20 cases of MRI BI-RADS 1-2. MRI sensitivity, specificity, positive predictive value, and negative predictive value were 88.8%, 76.9%, 84.2%, and 83.3%, respectively. PMID:22084735

  13. MRI in Prostate Cancer

    PubMed Central

    Ghafoori, Mahyar; Alavi, Manijeh; Aliyari Ghasabeh, Mounes

    2013-01-01

    Imaging studies play an important role in detection and management of prostate cancer and MRI especially with the use of endorectal coil because of high contrast resolution is recognized as the best imaging modality in evaluation of prostate cancer. Multiparametric MR study including T1 and T2 weighted images, diffusion weighted images, dynamic contrast study and MR spectroscopy is useful for detection and local staging of prostate cancer as well as posts treatment evaluation of patients either after surgery or radiation therapy for detection of local recurrence. PMID:24693403

  14. MRI breast screening in high-risk women: cancer detection and survival analysis.

    PubMed

    Evans, D Gareth; Gareth, Evans D; Kesavan, Nisha; Nisha, Kesavan; Lim, Yit; Yit, Lim; Gadde, Soujanye; Soujanye, Gadde; Hurley, Emma; Emma, Hurley; Massat, Nathalie J; Maxwell, Anthony J; Ingham, Sarah; Sarah, Ingham; Eeles, Rosalind; Rosalind, Eeles; Leach, Martin O; Howell, Anthony; Anthony, Howell; Duffy, Stephen W; Stephen, Duffy

    2014-06-01

    Women with a genetic predisposition to breast cancer tend to develop the disease at a younger age with denser breasts making mammography screening less effective. The introduction of magnetic resonance imaging (MRI) for familial breast cancer screening programs in recent years was intended to improve outcomes in these women. We aimed to assess whether introduction of MRI surveillance improves 5- and 10-year survival of high-risk women and determine the accuracy of MRI breast cancer detection compared with mammography-only or no enhanced surveillance and compare size and pathology of cancers detected in women screened with MRI + mammography and mammography only. We used data from two prospective studies where asymptomatic women with a very high breast cancer risk were screened by either mammography alone or with MRI also compared with BRCA1/2 carriers with no intensive surveillance. 63 cancers were detected in women receiving MRI + mammography and 76 in women receiving mammography only. Sensitivity of MRI + mammography was 93 % with 63 % specificity. Fewer cancers detected on MRI were lymph node positive compared to mammography/no additional screening. There were no differences in 10-year survival between the MRI + mammography and mammography-only groups, but survival was significantly higher in the MRI-screened group (95.3 %) compared to no intensive screening (73.7 %; p = 0.002). There were no deaths among the 21 BRCA2 carriers receiving MRI. There appears to be benefit from screening with MRI, particularly in BRCA2 carriers. Extended follow-up of larger numbers of high-risk women is required to assess long-term survival. PMID:24687378

  15. Morgagni hernia diagnosed by MRI

    Microsoft Academic Search

    Noriki Kamiya; Kohei Yokoi; Naoto Miyazawa; Shoichi Hishinuma; Yoshiro Ogata; Nobuhito Katayama

    1996-01-01

    We herein present a patient with Morgagni hernia which was diagnosed by magnetic resonance imaging (MRI). The patient had a progressively enlarging mass in the right cardiophrenic angle on chest roentgenogram. On computed tomography (CT) scans, the mass was revealed to have fat density and therefore was suspected to be either a lipoma or liposarcoma. MRI clearly demonstrated that the

  16. MRI segmentation: Methods and applications

    Microsoft Academic Search

    L. P. Clarke; R. P. Velthuizen; M. A. Camacho; J. J. Heine; M. Vaidyanathan; L. O. Hall; R. W. Thatcher; M. L. Silbiger

    1995-01-01

    The current literature on MRI segmentation methods is reviewed. Particular emphasis is placed on the relative merits of single image versus multispectral segmentation, and supervised versus unsupervised segmentation methods. Image pre-processing and registration are discussed, as well as methods of validation. The application of MRI segmentation for tumor volume measurements during the course of therapy is presented here as an

  17. [MRI symptomatology of primary intraspinal cord gliomas].

    PubMed

    Joubert, E; Idir, A B; Carlier, R; Belal, N; Hurth, M; Lacroix-Ciaudo, C; Ducot, B; Doyon, D

    1995-03-01

    MRI has now been recognized as the best technique for exploration of spinal tumours and, in particular, tumours within the spinal cord. Based on a retrospective study of 74 operated glial tumours, we are trying to define a specific semiology for intramedullary astrocytomas and ependymomas. Thirty-four cases were selected including 17 astrocytomas (7 low-grade, 10 high-grade) and 17 ependymomas (1 of which was grade III) for whom the pre-operative MRI examination was complete, with T1-weighted sequences without, then with gadolinium, and T2-weighted sequences. The examination was performed using a high-field and in most cases 1.5 Tesla machine. Analysis, correlated with operative data and pathology results, comprised on the one hand patients' distribution by age, sex and location of the tumour on the spinal cord, and on the other hand the MRI semiology concerning the sagittal and axial localization of the fleshy portion after gadolinium injection, the limits of the tumour, the homo- or heterogeneous character of its enhancement, the possible existence of stigmas of intra- or peritumoral chronic bleeding, and finally the presence or absence of associated cysts in the 34 exploitable cases. Some semiological differences were elicited between astrocytomas and ependymomas: the patient's age at the time of diagnosis was predominantly 0 to 20 for astrocytomas (astrocytomas 39%, ependymomas 4%), and the well-limited character of the fleshy portion of the tumour after gadolinium injection was found in 70% of ependymomas, 40% of high-grade astrocytomas and 14% of low-grade astrocytomas. The homogeneity of contrast enhancement in ependymomas has been classically defined, but it did not show in our series. Finally, it seems that high-grade astrocytomas are characterized by the rare presence of hemosiderin deposits (high-grade 20%, low-grade 57%, ependymomas 58%) and by the absence or reduced extension of overlying and underlying cysts. PMID:7707132

  18. MRI virtual biopsy and treatment of brain metastatic tumors with targeted nanobioconjugates: nanoclinic in the brain.

    PubMed

    Patil, Rameshwar; Ljubimov, Alexander V; Gangalum, Pallavi R; Ding, Hui; Portilla-Arias, Jose; Wagner, Shawn; Inoue, Satoshi; Konda, Bindu; Rekechenetskiy, Arthur; Chesnokova, Alexandra; Markman, Janet L; Ljubimov, Vladimir A; Li, Debiao; Prasad, Ravi S; Black, Keith L; Holler, Eggehard; Ljubimova, Julia Y

    2015-05-26

    Differential diagnosis of brain magnetic resonance imaging (MRI) enhancement(s) remains a significant problem, which may be difficult to resolve without biopsy, which can be often dangerous or even impossible. Such MRI enhancement(s) can result from metastasis of primary tumors such as lung or breast, radiation necrosis, infections, or a new primary brain tumor (glioma, meningioma). Neurological symptoms are often the same on initial presentation. To develop a more precise noninvasive MRI diagnostic method, we have engineered a new class of poly(?-l-malic acid) polymeric nanoimaging agents (NIAs). The NIAs carrying attached MRI tracer are able to pass through the blood-brain barrier (BBB) and specifically target cancer cells for efficient imaging. A qualitative/quantitative "MRI virtual biopsy" method is based on a nanoconjugate carrying MRI contrast agent gadolinium-DOTA and antibodies recognizing tumor-specific markers and extravasating through the BBB. In newly developed double tumor xenogeneic mouse models of brain metastasis this noninvasive method allowed differential diagnosis of HER2- and EGFR-expressing brain tumors. After MRI diagnosis, breast and lung cancer brain metastases were successfully treated with similar tumor-targeted nanoconjugates carrying molecular inhibitors of EGFR or HER2 instead of imaging contrast agent. The treatment resulted in a significant increase in animal survival and markedly reduced immunostaining for several cancer stem cell markers. Novel NIAs could be useful for brain diagnostic MRI in the clinic without currently performed brain biopsies. This technology shows promise for differential MRI diagnosis and treatment of brain metastases and other pathologies when biopsies are difficult to perform. PMID:25906400

  19. Quantum correlations and distinguishability of quantum states

    E-print Network

    Dominique Spehner

    2014-07-14

    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.

  20. Quantum correlations and distinguishability of quantum states

    SciTech Connect

    Spehner, Dominique [Université Grenoble Alpes and CNRS, Institut Fourier, F-38000 Grenoble, France and Laboratoire de Physique et Modélisation des Milieux Condensés, F-38000 Grenoble (France)

    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.

  1. Can cosmic parallax distinguish between anisotropic cosmologies?

    SciTech Connect

    Fontanini, Michele; West, Eric J. [Center for Particle Cosmology, Department of Physics and Astronomy, University of Pennsylvania, Philadelphia Pennsylvania 19104 (United States); Department of Physics, Syracuse University, Syracuse New York 13244 (United States); Trodden, Mark [Center for Particle Cosmology, Department of Physics and Astronomy, University of Pennsylvania, Philadelphia Pennsylvania 19104 (United States)

    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.

  2. Displaying perfusion MRI images as color intensity projections

    E-print Network

    Friso Hoefnagels; Keith S Cover; Ester Sanchez; Frank J. Lagerwaard

    2007-11-19

    Dynamic susceptibility-weighted contrast-enhanced (DSC) MRI or perfusion-MRI plays an important role in the non-invasive assessment of tumor vascularity. However, the large number of images provided by the method makes display and interpretation of the results challenging. Current practice is to display the perfusion information as relative cerebral blood volume maps (rCBV). Color intensity projections (CIPs) provides a simple, intuitive display of the perfusion-MRI data so that regional perfusion characteristics are intrinsically integrated into the anatomy structure the T2 images. The ease of use and quick calculation time of CIPs should allow it to be easily integrated into current analysis and interpretation pipelines.

  3. [Cardiac MRI: technology, clinical applications, and future directions].

    PubMed

    Pesenti-Rossi, D; Peyrou, J; Baron, N; Allouch, P; Aubert, S; Boueri, Z; Livarek, B

    2013-11-01

    The field of cardiovascular MRI has evolved rapidly over the past decade, feeding new applications across a broad spectrum of clinical and research areas. Advances in magnet hardware technology, and key developments such as segmented k-space acquisitions, advanced motion encoding techniques, ultra-rapid perfusion imaging and delayed myocardial enhancement imaging have all contributed to a revolution in how patients with ischemic and non-ischemic heart disease are diagnosed and treated. Actually, cardiac MRI is a widely accepted method as the "gold standard" for detection and characterization of many forms of cardiac diseases. The aim of this review is to present an overview of cardiac MRI technology, advances in clinical applications, and future directions. PMID:24035258

  4. Functional MRI and CT biomarkers in oncology.

    PubMed

    Winfield, J M; Payne, G S; deSouza, N M

    2015-04-01

    Imaging biomarkers derived from MRI or CT describe functional properties of tumours and normal tissues. They are finding increasing numbers of applications in diagnosis, monitoring of response to treatment and assessment of progression or recurrence. Imaging biomarkers also provide scope for assessment of heterogeneity within and between lesions. A wide variety of functional parameters have been investigated for use as biomarkers in oncology. Some imaging techniques are used routinely in clinical applications while others are currently restricted to clinical trials or preclinical studies. Apparent diffusion coefficient, magnetization transfer ratio and native T1 relaxation time provide information about structure and organization of tissues. Vascular properties may be described using parameters derived from dynamic contrast-enhanced MRI, dynamic contrast-enhanced CT, transverse relaxation rate (R2*), vessel size index and relative blood volume, while magnetic resonance spectroscopy may be used to probe the metabolic profile of tumours. This review describes the mechanisms of contrast underpinning each technique and the technical requirements for robust and reproducible imaging. The current status of each biomarker is described in terms of its validation, qualification and clinical applications, followed by a discussion of the current limitations and future perspectives. PMID:25578953

  5. Cyclic generalized projection MRI.

    PubMed

    Sarty, Gordon E

    2015-04-01

    Progress in the development of portable MRI hinges on the ability to use lightweight magnets that have non-uniform magnetic fields. An image encoding method and mathematical procedure for recovering the image from the NMR signal from non-uniform magnets with closed isomagnetic contours is given. Individual frequencies in an NMR signal from an object in a non-uniform magnetic field give rise to integrals of the object along contours of constant magnetic field: generalized projections. With closed isomagnetic field contours a simple, cyclic, direct reconstruction of the image from the generalized projections is possible when the magnet and RF transmit coil are held fixed relative to the imaged object while the RF receive coil moves. Numerical simulations, using the Shepp and Logan mathematical phantom, were completed to show that the mathematical method works and to illustrate numerical limitations. The method is numerically verified and exact reconstruction demonstrated for discrete mathematical image phantoms. Correct knowledge of the RF receive field is necessary or severe image distortions will result. The cyclic mathematical reconstruction method presented here will be useful for portable MRI schemes that use non-uniform magnets with closed isomagnetic contours along with mechanically or electronically moving the RF receive coils. PMID:25532468

  6. MRI Images Compression Using Curvelets Transforms

    NASA Astrophysics Data System (ADS)

    Beladgham, M.; Hacene, I. Boucli; Taleb-Ahmed, A.; Khélif, M.

    2008-06-01

    In the field of medical diagnostics, interested parties have resorted increasingly to medical imaging, it is well established that the accuracy and completeness of diagnosis are initially connected with the image quality, but the quality of the image is itself dependent on a number of factors including primarily the processing that an image must undergo to enhance its quality. We are interested in MRI medical image compression by Curvelets, of which we have proposed in this paper the compression algorithm FDCT using the wrapping method. In order to enhance the compression algorithm by FDCT, we have compared the results obtained with wavelet and Ridgelet transforms. The results are very satisfactory regarding compression ratio, and the computation time and quality of the compressed image compared to those of traditional methods.

  7. Quantitative Serial MRI of the Treated Fibroid Uterus

    PubMed Central

    Williams, Alistair R. W.; McKillop, Graham; Walker, Jane; Horne, Andrew W.; Newby, David E.; Anderson, Richard A.; Semple, Scott I.; Marshall, Ian; Lewis, Steff C.; Millar, Robert P.; Bastin, Mark E.; Critchley, Hilary O. D.

    2014-01-01

    Objective There are no long-term medical treatments for uterine fibroids, and non-invasive biomarkers are needed to evaluate novel therapeutic interventions. The aim of this study was to determine whether serial dynamic contrast-enhanced MRI (DCE-MRI) and magnetization transfer MRI (MT-MRI) are able to detect changes that accompany volume reduction in patients administered GnRH analogue drugs, a treatment which is known to reduce fibroid volume and perfusion. Our secondary aim was to determine whether rapid suppression of ovarian activity by combining GnRH agonist and antagonist therapies results in faster volume reduction. Methods Forty women were assessed for eligibility at gynaecology clinics in the region, of whom thirty premenopausal women scheduled for hysterectomy due to symptomatic fibroids were randomized to three groups, receiving (1) GnRH agonist (Goserelin), (2) GnRH agonist+GnRH antagonist (Goserelin and Cetrorelix) or (3) no treatment. Patients were monitored by serial structural, DCE-MRI and MT-MRI, as well as by ultrasound and serum oestradiol concentration measurements from enrolment to hysterectomy (approximately 3 months). Results A volumetric treatment effect assessed by structural MRI occurred by day 14 of treatment (9% median reduction versus 9% increase in untreated women; P?=?0.022) and persisted throughout. Reduced fibroid perfusion and permeability assessed by DCE-MRI occurred later and was demonstrable by 2–3 months (43% median reduction versus 20% increase respectively; P?=?0.0093). There was no apparent treatment effect by MT-MRI. Effective suppression of oestradiol was associated with early volume reduction at days 14 (P?=?0.041) and 28 (P?=?0.0061). Conclusion DCE-MRI is sensitive to the vascular changes thought to accompany successful GnRH analogue treatment of uterine fibroids and should be considered for use in future mechanism/efficacy studies of proposed fibroid drug therapies. GnRH antagonist administration does not appear to accelerate volume reduction, though our data do support the role of oestradiol suppression in GnRH analogue treatment of fibroids. Trial Registration ClinicalTrials.gov NCT00746031 PMID:24608161

  8. Detection and Clinical Significance of Sternal Lesions on Breast MRI.

    PubMed

    Schaefer, Amanda R; Yang, Limin; Park, Jeong Mi; Xiong, Jinhu; Fajardo, Laurie L

    2015-07-01

    The purpose of this study is to characterize sternal lesions detected on breast magnetic resonance imaging (MRI), compare MRI detection of sternal lesions with other imaging modalities (bone scan, positron emission tomography/computed tomography (PET/CT) and chest CT), and ascertain how often patient management is altered by discovery of sternal lesions. Retrospective review of 1143 breast MRIs between 2007 and 2012 identified 17 patients with sternal lesions including 15 patients with newly diagnosed breast cancer and two patients with remote history of breast cancer. Tumor size, histopathology, receptor status, nodal and distant metastasis, and images of breast MRI, and other modalities were reviewed. Sternal lesions in 9 of the 17 patients were determined to be malignant (metastasis) either by biopsy or presence of widespread metastases. Sternal lesions in 8 of the 17 were benign, confirmed by biopsy or presumed benign as not detected by other modalities. The malignant group had statistically significant larger breast cancer size (malignant: 6.4 cm; benign: 2.3 cm), a higher percentage of diffuse sternal lesions (malignant: 56%; benign: 0%), and more frequently showed rapid initial enhancing (malignant: 100%; benign: 63%) and delayed washout curves (malignant: 67%; benign: 13%). Although not statistically significant, the malignant group had a higher frequency of invasive lobular carcinoma (malignant: 44%; benign: 13%) and more lymph node involvement (malignant: 78%; benign: 50%). Breast MRI detected more sternal lesions than did bone scan, PET/CT and chest CT. Four of the 17 (24%) patients were upgraded to stage 4 due to unsuspected metastatic sternal lesions on breast MRI. In conclusion, breast MRI is more sensitive than other modalities in detecting sternal lesions. Sternal metastases occur more frequently in aggressive breast cancer and exhibit malignant-type dynamics on breast MRI. Detection of unsuspected sternal metastasis alters staging and improves patient management with more appropriate treatment. PMID:25864435

  9. Real-Time MRI-Guided Endovascular Recanalization of Chronic Total Arterial Occlusion in a Swine Model

    PubMed Central

    Raval, Amish N.; Karmarkar, Parag V.; Guttman, Michael A.; Ozturk, Cengizhan; Sampath, Smita; DeSilva, Ranil; Aviles, Ronnier J.; Xu, Minnan; Wright, Victor J.; Schenke, William H.; Kocaturk, Ozgur; Dick, Alexander J.; Raman, Venkatesh K.; Atalar, Ergin; McVeigh, Elliot R.; Lederman, Robert J.

    2006-01-01

    Background Endovascular recanalization (guidewire traversal) of peripheral artery chronic total occlusion (CTO) can be challenging. X-Ray angiography resolves CTO poorly. Virtually “blind” device advancement during X-ray-guided interventions can lead to procedure failure, perforation and hemorrhage. Alternatively, magnetic resonance imaging (MRI) may delineate the artery within the occluded segment to enhance procedural safety and success. We hypothesized that real-time MRI (rtMRI) guided CTO recanalization can be accomplished in an animal model. Methods and Results Carotid artery CTO was created by balloon injury in 19 lipid overfed swine. After 6–8 weeks, two underwent direct necropsy analysis for histology, three underwent primary X-ray-guided CTO recanalization attempts, and the remaining 14 underwent rtMRI-guided recanalization attempts in a 1.5T interventional MRI system. rtMRI intervention used custom CTO catheters and guidewires that incorporated MRI receiver antennae to enhance device visibility. The mean length of the occluded segments was 13.3 ± 1.6cm. rtMRI-guided CTO recanalization was successful in 11/14 swine and only 1/3 swine using X-ray alone. After unsuccessful rtMRI (n = 3), X-ray-guided attempts also were all unsuccessful. Conclusions Recanalization of long CTO is feasible entirely using rtMRI guidance. Low profile clinical-grade devices will be required to translate this experience to humans. Endovascular recanalization of chronic total arterial occlusion (CTO) is challenging under conventional X-ray guidance because devices are advanced almost blindly. MRI can image CTO borders and luminal contents, and could potentially guide these procedures. We test the feasibility of real-time MRI guided wire traversal in a swine model of peripheral artery CTO using custom active MRI catheters. PMID:16490819

  10. Selection of diagnostic features on breast MRI to differentiate between malignant and benign lesions using computer-aided diagnosis: differences in lesions presenting as mass and non-mass-like enhancement

    E-print Network

    2010-01-01

    fuzzy c-means (FCM)-based approach for computerized segmentation of breast lesions in dynamic contrast- enhanced MR images.images lesion segmentation for the analysis of enhancement kinetic features [32]. The remaining three studies used fuzzy c-means (

  11. Adrenal pseudomasses due to varices: angiographic-CT-MRI-pathologic correlations

    SciTech Connect

    Brady, T.M.; Gross, B.H.; Glazer, G.M. Williams, D.M.

    1985-08-01

    Periadrenal and adrenal portosystemic collaterals are a recently reported cause of adrenal pseudotumor on computed tomography (CT). Nine patients with this left adrenal pseudotumor illustrate its typical position and appearance on CT, angiography, CT-angiography, and magnetic resonance imaging (MRI). The anatomic basis for variceal adrenal pseudotumors is the left inferior phrenic vein, which passes immediately anterior to the left adrenal gland and which serves as a collateral pathway from splenic to left renal vein in portal hypertension. Thus, unlike previously described adrenal pseudotumors, these venous collaterals are not anatomically distinguishable from the adrenal gland on CT. Bolus dynamic CT is usually diagnostic, but in equivocal cases, MRI may prove useful.

  12. The role of whole-body MRI in pediatric oncology.

    PubMed

    Atkin, Karen L; Ditchfield, Michael R

    2014-07-01

    Pediatric whole-body (WB) magnetic resonance imaging (MRI) is an established technique that, with improved accessibility and advances in technology, is being used with increasing frequency for a wide variety of applications. The advantages of WB MRI (over other imaging modalities), particularly its lack of ionizing radiation (of particular concern in pediatric imaging due to children's increased sensitivity to ionizing radiation) and the ability of MRI to image the bone marrow, solid organs, and soft tissues with superior soft-tissue contrast resolution to other techniques, promise that WB MRI has great potential in conditions that are diffuse or multifocal. There is particular interest in its role in the field of pediatric oncology (eg, lymphoma, neuroblastoma, sarcoma, and Langerhans cell histiocytosis). The main disadvantages of WB MRI are its relatively long scanning times, artifacts from motion (requiring patient cooperation or general anesthesia), and limited specificity. However, advances in hardware and imaging techniques, including additional sequences (out-of-phase imaging, diffusion-weighted imaging, and contrast enhancement) are reducing the impact of some of these challenges. PMID:24072253

  13. Molecular MRI of Collagen to Diagnose and Stage Liver Fibrosis

    PubMed Central

    Fuchs, Bryan C.; Wang, Huifang; Yang, Yan; Wei, Lan; Polasek, Miloslav; Schühle, Daniel T.; Lauwers, Gregory Y.; Parkar, Ashfaq; Sinskey, Anthony J.; Tanabe, Kenneth K.; Caravan, Peter

    2013-01-01

    Background & Aims The gold standard in assessing liver fibrosis is biopsy despite limitations like invasiveness and sampling error and complications including morbidity and mortality. Therefore, there is a major unmet medical need to quantify fibrosis noninvasively to facilitate early diagnosis of chronic liver disease and provide a means to monitor disease progression. The goal of this study was to evaluate the ability of several magnetic resonance imaging (MRI) techniques to stage liver fibrosis. Methods A gadolinium (Gd)-based MRI probe targeted to type I collagen (termed EP-3533) was utilized to noninvasively stage liver fibrosis in a carbon tetrachloride (CCl4) mouse model and the results were compared to other MRI techniques including relaxation times, diffusion and magnetization transfer measurements. Results The most sensitive MR biomarker was the change in liver:muscle contrast to noise ratio (?CNR) after EP-3533 injection. We observed a strong positive linear correlation between ?CNR and liver hydroxyproline (i.e. collagen) levels (r=0.89) as well as ?CNR and conventional Ishak fibrosis scoring. In addition, the area under the receiver operating curve (AUR0C) for distinguishing early (Ishak ?3) from late (Ishak ? 4) fibrosis was 0.942±0.052 (p<0.001). By comparison, other MRI techniques were not as sensitive to changes in fibrosis in this model. Conclusions We have developed a MRI technique using a collagen-specific probe for diagnosing and staging liver fibrosis, and validated it in the CCl4 mouse model. This approach should provide a better means to monitor disease progression in patients. PMID:23838178

  14. [Is MRI monitoring useful in clinical practice in patients with multiple sclerosis? No].

    PubMed

    Edan, G

    2013-11-01

    Is regular MRI monitoring useful in clinical practice in multiple sclerosis patients treated with disease modifying therapy (DMT) drugs? My answer is no. Tacking a DMT drug is not by itself a pertinent criterion for requiring a systematic MRI monitoring in MS patients. Five clinical criteria should be taken into consideration before prescribing regular MRI examinations. The clinical form of the disease: MRI monitoring in DMT treated patients, has been demonstrated as useful only in pure relapsing-remitting MS patients. Up to now, there is no convincing demonstration of therapeutic efficacy with any DMT drug, neither first-line nor second-line drugs in patients with primary or secondary progressive MS disease. The duration of the disease, epidemiological data leading to the concept of a two-stage disability progression in MS, emphasizes the importance of treating as early as possible RRMS patients in order to stop accumulation of new focal MRI CNS lesions. In this regard, an annual monitoring for the 5 first years of the disease looks reasonable in order to better personalize the treatment choice among the few approved DMT drugs. The duration of the treatment: a first MRI assessment at month 6 after initiating a new DMT drug is adequate in order to better distinguish responder versus no responder. The persistence of Gado+lesions at 6 months is a strong indication for considering alternative treatment. The disease activity: both criteria, clinical and MRI, are needed to recognized very active or aggressive relapsing MS patients, leading to decide a rapid use of second-line treatment therapy. The treatment choice: in JC positive MS patients treated with natalizumab, the risk of PML is as high as more than 1 % in those JC+MS patients that are treated continuously more than 24 months. A regular MRI monitoring (3 or 6months) is recommended in order to detect as early as possible MRI abnormalities suggesting PML. PMID:24125462

  15. Creating a Pseudo-CT from MRI for MRI-only based Radiation

    E-print Network

    MRI images. Creating a pseudo-CT from MRI would eliminate the need for a real CT scan and thus. CT head scans were also acquired using a standard protocol. A registration of the CT and MRI imageCreating a Pseudo-CT from MRI for MRI-only based Radiation Therapy Planning Daniel Andreasen

  16. MRI of plants and foods

    NASA Astrophysics Data System (ADS)

    Van As, Henk; van Duynhoven, John

    2013-04-01

    The importance and prospects for MRI as applied to intact plants and to foods are presented in view of one of humanity's most pressing concerns, the sustainable and healthy feeding of a worldwide increasing population. Intact plants and foods have in common that their functionality is determined by complex multiple length scale architectures. Intact plants have an additional level of complexity since they are living systems which critically depend on transport and signalling processes between and within tissues and organs. The combination of recent cutting-edge technical advances and integration of MRI accessible parameters has the perspective to contribute to breakthroughs in understanding complex regulatory plant performance mechanisms. In food science and technology MRI allows for quantitative multi-length scale structural assessment of food systems, non-invasive monitoring of heat and mass transport during shelf-life and processing, and for a unique view on food properties under shear. These MRI applications are powerful enablers of rationally (re)designed food formulations and processes. Limitations and bottlenecks of the present plant and food MRI methods are mainly related to short T2 values and susceptibility artefacts originating from small air spaces in tissues/materials. We envisage cross-fertilisation of solutions to overcome these hurdles in MRI applications in plants and foods. For both application areas we witness a development where MRI is moving from highly specialised equipment to mobile and downscaled versions to be used by a broad user base in the field, greenhouse, food laboratory or factory.

  17. Documenting the location of systematic transrectal ultrasound-guided prostate biopsies: correlation with multi-parametric MRI.

    PubMed

    Turkbey, Baris; Xu, Sheng; Kruecker, Jochen; Locklin, Julia; Pang, Yuxi; Shah, Vijay; Bernardo, Marcelino; Baccala, Angelo; Rastinehad, Ardeshir; Benjamin, Compton; Merino, Maria J; Wood, Bradford J; Choyke, Peter L; Pinto, Peter A

    2011-01-01

    During transrectal ultrasound (TRUS)-guided prostate biopsies, the actual location of the biopsy site is rarely documented. Here, we demonstrate the capability of TRUS-magnetic resonance imaging (MRI) image fusion to document the biopsy site and correlate biopsy results with multi-parametric MRI findings. Fifty consecutive patients (median age 61 years) with a median prostate-specific antigen (PSA) level of 5.8 ng/ml underwent 12-core TRUS-guided biopsy of the prostate. Pre-procedural T2-weighted magnetic resonance images were fused to TRUS. A disposable needle guide with miniature tracking sensors was attached to the TRUS probe to enable fusion with MRI. Real-time TRUS images during biopsy and the corresponding tracking information were recorded. Each biopsy site was superimposed onto the MRI. Each biopsy site was classified as positive or negative for cancer based on the results of each MRI sequence. Sensitivity, specificity, and receiver operating curve (ROC) area under the curve (AUC) values were calculated for multi-parametric MRI. Gleason scores for each multi-parametric MRI pattern were also evaluated. Six hundred and 5 systemic biopsy cores were analyzed in 50 patients, of whom 20 patients had 56 positive cores. MRI identified 34 of 56 positive cores. Overall, sensitivity, specificity, and ROC area values for multi-parametric MRI were 0.607, 0.727, 0.667, respectively. TRUS-MRI fusion after biopsy can be used to document the location of each biopsy site, which can then be correlated with MRI findings. Based on correlation with tracked biopsies, T2-weighted MRI and apparent diffusion coefficient maps derived from diffusion-weighted MRI are the most sensitive sequences, whereas the addition of delayed contrast enhancement MRI and three-dimensional magnetic resonance spectroscopy demonstrated higher specificity consistent with results obtained using radical prostatectomy specimens. PMID:21450548

  18. Documenting the location of systematic transrectal ultrasound-guided prostate biopsies: correlation with multi-parametric MRI

    PubMed Central

    Xu, Sheng; Kruecker, Jochen; Locklin, Julia; Pang, Yuxi; Shah, Vijay; Bernardo, Marcelino; Baccala, Angelo; Rastinehad, Ardeshir; Benjamin, Compton; Merino, Maria J.; Wood, Bradford J.; Choyke, Peter L.; Pinto, Peter A.

    2011-01-01

    Abstract During transrectal ultrasound (TRUS)-guided prostate biopsies, the actual location of the biopsy site is rarely documented. Here, we demonstrate the capability of TRUS-magnetic resonance imaging (MRI) image fusion to document the biopsy site and correlate biopsy results with multi-parametric MRI findings. Fifty consecutive patients (median age 61 years) with a median prostate-specific antigen (PSA) level of 5.8?ng/ml underwent 12-core TRUS-guided biopsy of the prostate. Pre-procedural T2-weighted magnetic resonance images were fused to TRUS. A disposable needle guide with miniature tracking sensors was attached to the TRUS probe to enable fusion with MRI. Real-time TRUS images during biopsy and the corresponding tracking information were recorded. Each biopsy site was superimposed onto the MRI. Each biopsy site was classified as positive or negative for cancer based on the results of each MRI sequence. Sensitivity, specificity, and receiver operating curve (ROC) area under the curve (AUC) values were calculated for multi-parametric MRI. Gleason scores for each multi-parametric MRI pattern were also evaluated. Six hundred and 5 systemic biopsy cores were analyzed in 50 patients, of whom 20 patients had 56 positive cores. MRI identified 34 of 56 positive cores. Overall, sensitivity, specificity, and ROC area values for multi-parametric MRI were 0.607, 0.727, 0.667, respectively. TRUS-MRI fusion after biopsy can be used to document the location of each biopsy site, which can then be correlated with MRI findings. Based on correlation with tracked biopsies, T2-weighted MRI and apparent diffusion coefficient maps derived from diffusion-weighted MRI are the most sensitive sequences, whereas the addition of delayed contrast enhancement MRI and three-dimensional magnetic resonance spectroscopy demonstrated higher specificity consistent with results obtained using radical prostatectomy specimens. PMID:21450548

  19. Absolute Quantification of Adipose Tissue Fat Mass by MRI Using a Signal Intensity Based Model , and K. S. Nayak1

    E-print Network

    Southern California, University of

    Absolute Quantification of Adipose Tissue Fat Mass by MRI Using a Signal Intensity Based Model H. HD capability is useful in identifying abdominal adipose tissue (AT) depots, as well as fatty, water, and proteins) is distinguished from lean tissue due to their high signal intensity [1]. Another

  20. California Policy Should Distinguish Biofuels by Differential Global Warming Effects

    E-print Network

    Kammen, Daniel M.

    California Policy Should Distinguish Biofuels by Differential Global Warming Effects by Richard J: _______________________________________ Date #12;California Policy Should Distinguish Biofuels by Differential Global Warming Effects Richard J, 2006 #12;#12;ABSTRACT California Policy Should Distinguish Biofuels by Differential Global Warming

  1. MRI of hepatocellular carcinoma: an update of current practices

    PubMed Central

    Arif-Tiwari, Hina; Kalb, Bobby; Chundru, Surya; Sharma, Puneet; Costello, James; Guessner, Rainner W.; Martin, Diego R.

    2014-01-01

    Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and liver transplantation is the optimal treatment for selected patients with HCC and chronic liver disease (CLD). Accurate selection of patients for transplantation is essential to maximize patient outcomes and ensure optimized allocation of donor organs. Magnetic resonance imaging (MRI) is a powerful tool for the detection, characterization, and staging of HCC. In patients with CLD, the MRI findings of an arterial-enhancing mass with subsequent washout and enhancing capsule on delayed interstitial phase images are diagnostic for HCC. Major organizations with oversight for organ donor distribution, such as The Organ Procurement and Transplantation Network (OPTN), accept an imaging diagnosis of HCC, no longer requiring tissue biopsy. In patients that are awaiting transplantation, or are not candidates for liver transplantation, localized therapies such as transarterial chemoembolization and radiofrequency ablation may be offered. MRI can be used to monitor treatment response. The purpose of this review article is to describe the role of imaging methods in the diagnosis, staging, and follow-up of HCC, with particular emphasis on established and evolving MRI techniques employing nonspecific gadolinium chelates, hepatobiliary contrast agents, and diffusion weighted imaging. We also briefly review the recently developed Liver Imaging Reporting and Data System (LI-RADS) formulating a standardized terminology and reporting structure for evaluation of lesions detected in patients with CLD. PMID:24808419

  2. Renal-related perinephric fluid collections: MRI findings.

    PubMed

    Balci, N Cem; Akun, Elif; Erturk, Mehmet; Saglam, Sezer; Inan, Nagihan; Balci, Yesim

    2005-06-01

    We retrospectively reviewed MR studies on 10 patients with renal-related perinephric fluid collections who underwent MRI in three institutions between January 2001 and August 2004. All patients underwent MRI of the abdomen and T1-weighted, T2-weighted and serial contrast-enhanced images, including delayed-phase contrast-enhanced images 10-12 min after contrast injection, were obtained. Perinephric fluid collections in 5 patients revealed MRI findings of simple fluid content (i.e., hypointense on T1-weighted images and hyperintense on T2-weighted images). In another 5 patients, a complex perinephric fluid content (i.e., mixed hyper/hypointense on T1-weighted images and mixed hypo/hyperintense on T2-weighted images compatible with blood breakdown products and pus) was observed. In 5 patients, contrast extravasation on late-phase images that was compatible with urine leak was demonstrated. Our results suggest that MRI may determine the content of perinephric fluid collections on noncontrast T1-weighted and T2-weighted images and that contrast extravasation on late-phase images is associated with urine extravasation from renal collecting systems. PMID:16051043

  3. The Emanuel Saxe Distinguished Lectures in Accounting

    NSDL National Science Digital Library

    From the Stan Ross Department of Accountancy at Baruch College of the City University of New York, the Emanuel Saxe Distinguished Lectures in Accounting, a series of public lectures, are in the process of being digitized. The lectures date back to 1973 and include the 1997 speech by Michael H. Sutton, Chief Accountant, Securities and Exchange Commission, entitled "Financial Reporting and Investor Protection"; "FASB in my Rear View Mirror," a speech given in 1996 by Robert J. Swieringa, Dean of the Johnson School of Management, Cornell University; and a 1973 lecture from David M. Hawkins, Professor of Business Administration, Graduate School of Business Administration, Harvard University, on "Financial Accounting, The Standards Board, and Economic Development." Lecture transcripts, in HTML format, also include introductory notes and footnotes.

  4. Multiparametric MRI of solid renal masses: pearls and pitfalls.

    PubMed

    Ramamurthy, N K; Moosavi, B; McInnes, M D F; Flood, T A; Schieda, N

    2015-03-01

    Functional imaging [diffusion-weighted imaging (DWI) and dynamic contrast enhancement (DCE)] techniques combined with T2-weighted (T2W) and chemical-shift imaging (CSI), with or without urography, constitutes a comprehensive multiparametric (MP) MRI protocol of the kidneys. MP-MRI of the kidneys can be performed in a time-efficient manner. Breath-hold sequences and parallel imaging should be used to reduce examination time and improve image quality. Increased T2 signal intensity (SI) in a solid renal nodule is specific for renal cell carcinoma (RCC); whereas, low T2 SI can be seen in RCC, angiomyolipoma (AML), and haemorrhagic cysts. Low b-value DWI can replace conventional fat-suppressed T2W. DWI can be performed free-breathing (FB) with two b-values to reduce acquisition time without compromising imaging quality. RCC demonstrates restricted diffusion; however, restricted diffusion is commonly seen in AML and in chronic haemorrhage. CSI must be performed using the correct echo combination at 3 T or T2* effects can mimic intra-lesional fat. Two-dimensional (2D)-CSI has better image quality compared to three-dimensional (3D)-CSI, but volume averaging in small lesions can simulate intra-lesional fat using 2D techniques. SI decrease on CSI is present in both AML and clear cell RCC. Verification of internal enhancement with MRI can be challenging and is improved with image subtraction. Subtraction imaging is prone to errors related to spatial misregistration, which is ameliorated with expiratory phase imaging. SI ratios can be used to confirm subtle internal enhancement and enhancement curves are predictive of RCC subtype. MR urography using conventional extracellular gadolinium must account for T2* effects; however, gadoxetic acid enhanced urography is an alternative. The purpose of this review it to highlight important technical and interpretive pearls and pitfalls encountered with MP-MRI of solid renal masses. PMID:25472466

  5. Potential Clinical Applications for Spinal Functional MRI

    PubMed Central

    Kornelsen, Jennifer; Mackey, Sean

    2010-01-01

    Functional MRI (fMRI) of the spinal cord is a noninvasive technique for obtaining information regarding spinal cord neuronal function. This article provides a brief overview of recent developments in spinal cord fMRI and outlines potential applications, as well as the limitations that must be overcome, for using spinal fMRI in the clinic. This technique is currently used for research purposes, but significant potential exists for spinal fMRI to become an important clinical tool. PMID:17504642

  6. Automated colorectal tumour segmentation in DCE-MRI using supervoxel neighbourhood contrast characteristics.

    PubMed

    Irving, Benjamin; Cifor, Amalia; Papiez, Bart?omiej W; Franklin, Jamie; Anderson, Ewan M; Brady, Sir Michael; Schnabel, Julia A

    2014-01-01

    Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a powerful protocol for assessing tumour progression from changes in tissue contrast enhancement. Manual colorectal tumour delineation is a challenging and time consuming task due to the complex enhancement patterns in the 4D sequence. There is a need for a consistent approach to colorectal tumour segmentation in DCE-MRI and we propose a novel method based on detection of the tumour from signal enhancement characteristics of homogeneous tumour subregions and their neighbourhoods. Our method successfully detected 20 of 23 cases with a mean Dice score of 0.68 +/- 0.15 compared to expert annotations, which is not significantly different from expert inter-rater variability of 0.73 +/- 0.13 and 0.77 +/- 0.10. In comparison, a standard DCE-MRI tumour segmentation technique, fuzzy c-means, obtained a Dice score of 0.28 +/- 0.17. PMID:25333169

  7. The utility of cardiac MRI in diagnosis of infective endocarditis: preliminary results

    PubMed Central

    Dursun, Memduh; Y?lmaz, Sabri; Y?lmaz, Erdem; Y?lmaz, Ravza; Onur, ?mran; Oflaz, Hüseyin; Dindar, Aygün

    2015-01-01

    PURPOSE We aimed to evaluate the utility of cardiac magnetic resonance imaging (MRI) for the diagnosis of infective endocarditis (IE). METHODS Sixteen patients with a preliminary diagnosis of IE (10 women and six men; age range, 4–66 years) were referred for cardiac MRI. MRI sequences were as follows: echo-planar cine true fast imaging with steady-state precession (true-FISP), dark-blood fast spin echo T1-weighted imaging, T2-weighted imaging, dark-blood half-Fourier single shot turbo spin echo (HASTE), and early contrast-enhanced first-pass fast low-angle shot (FLASH). Delayed contrast-enhanced images were obtained using three-dimensional inversion recovery FLASH after 15±5 min. The MRI features were evaluated, including valvular pathologies on cine MRI and contrast enhancement on the walls of the cardiac chambers, major thoracic vasculature, and paravalvular tissue, attributable to endothelial extension of inflammation on contrast-enhanced images. RESULTS Fourteen valvular vegetations were detected in eleven patients on cardiac MRI. It was not possible to depict valvular vegetations in five patients. Vegetations were detected on the aortic valve (n=7), mitral valve (n=3), tricuspid and pulmonary valves (n=1). Delayed contrast enhancement attributable to extension of inflammation was observed on the aortic wall and aortic root (n=11), paravalvular tissue (n=4), mitral valve (n=2), walls of the cardiac chambers (n=6), interventricular septum (n=3), and wall of the pulmonary artery and superior mesenteric artery (n=1). CONCLUSION Valvular vegetation features of IE can be detected by MRI. Moreover, in the absence of vegetations, detection of delayed enhancement representing endothelial inflammation of the cardiovascular structures can contribute to the diagnosis and treatment planning of IE. PMID:25430531

  8. MRI follow-up in a case of clinically diagnosed Creutzfeld-Jakob disease.

    PubMed

    Hutzelmann, A; Biederer, J

    1998-01-01

    We report the case of a 75-year-old woman suffering from Creutzfeld-Jakob disease (CJD). As brain biopsy was refused, diagnosis had to be based on clinical examination, EEC and findings on cranial MRI. Over a 4-month period MRI examinations demonstrated progressive cortical atrophy and bilateral enhanced signal intensity on T2-weighted images of caudate nuclei and putamina indicating development of spongioform degeneration. As clinical course and the characteristic pattern of brain lesions corresponded to cases of neuropathologically confirmed CJD, we suggest that MRI should be considered a valuable diagnostic tool in clinical diagnosis of the disease. PMID:9510575

  9. The value of MRI in a case of Tolosa-Hunt syndrome

    Microsoft Academic Search

    Zeki Odaba?i; Zeki Gökçil; Serhan Atilla; Yüksel Pabu?çu; Okay Vural; Muzaffer Yardim

    1997-01-01

    We report a case of Tolosa-Hunt syndrome (THS) in which the lesion has been demonstrated by magnetic resonance imaging (MRI), computed tomography (CT), and angiography. A healthy 23-year-old man developed an acute painful ophthalmoplegia on the right side. CT and MRI scans revealed asymmetric enlargement of the right cavernous sinus with contrast enhancement extending down to the region of trigeminal

  10. Quintuple-modality (SERS-MRI-CT-TPL-PTT) plasmonic nanoprobe for theranostics.

    PubMed

    Liu, Yang; Chang, Zheng; Yuan, Hsiangkuo; Fales, Andrew M; Vo-Dinh, Tuan

    2013-12-21

    A unique quintuple-modality theranostic nanoprobe (QMT) is developed with gold nanostars for surface-enhanced Raman scattering (SERS), magnetic resonance imaging (MRI), computed tomography (CT), two-photon luminescence (TPL) imaging and photothermal therapy (PTT). The synthesized gold nanostars were tagged with a SERS reporter and linked with an MRI contrast agent Gd(3+). In vitro experiments demonstrated the developed QMT nanoprobe to be a potential theranostic agent for future biomedical applications. PMID:24162005

  11. DCE-MRI biomarkers in the clinical evaluation of antiangiogenic and vascular disrupting agents

    Microsoft Academic Search

    J P B O'Connor; A Jackson; G J M Parker; G C Jayson; JPB O'Connor

    2007-01-01

    Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is now frequently used in early clinical trial assessment of antiangiogenic and vascular disrupting compounds. Evidence of drug efficacy and dose-dependent response has been demonstrated with some angiogenesis inhibitors. This review highlights the critical issues that influence T1-weighted DCE-MRI data acquisition and analysis, identifies important areas for future development and reviews the clinical trial

  12. In Vivo Molecular MRI Imaging of Prostate Cancer by Targeting PSMA with Polypeptide-Labeled Superparamagnetic Iron Oxide Nanoparticles

    PubMed Central

    Zhu, Yunkai; Sun, Ying; Chen, Yaqing; Liu, Weiyong; Jiang, Jun; Guan, Wenbin; Zhang, Zhongyang; Duan, Yourong

    2015-01-01

    The prostate specific membrane antigen (PSMA) is broadly overexpressed on prostate cancer (PCa) cell surfaces. In this study, we report the synthesis, characterization, in vitro binding assay, and in vivo magnetic resonance imaging (MRI) evaluation of PSMA targeting superparamagnetic iron oxide nanoparticles (SPIONs). PSMA-targeting polypeptide CQKHHNYLC was conjugated to SPIONs to form PSMA-targeting molecular MRI contrast agents. In vitro studies demonstrated specific uptake of polypeptide-SPIONs by PSMA expressing cells. In vivo MRI studies found that MRI signals in PSMA-expressing tumors could be specifically enhanced with polypeptide-SPION, and further Prussian blue staining showed heterogeneous deposition of SPIONs in the tumor tissues. Taken altogether, we have developed PSMA-targeting polypeptide-SPIONs that could specifically enhance MRI signal in tumor-bearing mice, which might provide a new strategy for the molecular imaging of PCa. PMID:25927579

  13. Parallel MRI at microtesla fields

    Microsoft Academic Search

    Vadim S. Zotev; Petr L. Volegov; Andrei N. Matlashov; Michelle A. Espy; John C. Mosher; Robert H. Kraus

    2008-01-01

    Parallel imaging techniques have been widely used in high-field magnetic resonance imaging (MRI). Multiple receiver coils have been shown to improve image quality and allow accelerated image acquisition. Magnetic resonance imaging at ultra-low fields (ULF MRI) is a new imaging approach that uses SQUID (superconducting quantum interference device) sensors to measure the spatially encoded precession of pre-polarized nuclear spin populations

  14. Cardiovascular Applications of Hyperpolarized MRI

    Microsoft Academic Search

    Damian J. Tyler

    2011-01-01

    Many applications of MRI are limited by an inherently low sensitivity. Previous attempts to overcome this insensitivity have\\u000a focused on the use of MRI systems with stronger magnetic fields. However, the gains that can be achieved in this way are relatively\\u000a small and increasing the magnetic field invariably leads to greater technical challenges. More recently, the development of\\u000a a range

  15. Compressed sensing MRI: a review.

    PubMed

    Geethanath, Sairam; Reddy, Rashmi; Konar, Amaresha Shridhar; Imam, Shaikh; Sundaresan, Rajagopalan; D R, Ramesh Babu; Venkatesan, Ramesh

    2013-01-01

    Compressed sensing (CS) is a mathematical framework that reconstructs data from highly undersampled measurements. To gain acceleration in acquisition time, CS has been applied to MRI and has been demonstrated on diverse MRI methods. This review discusses the important requirements to qualify MRI to become an optimal application of CS, namely, sparsity, pseudo-random undersampling, and nonlinear reconstruction. By utilizing concepts of transform sparsity and compression, CS allows acquisition of only the important coefficients of the signal during the acquisition. A priori knowledge of MR images specifically related to transform sparsity is required for the application of CS. In this paper, Section I introduces the fundamentals of CS and the idea of CS as applied to MRI. The requirements for application of CS to MRI is discussed in Section II, while the various acquisition techniques, reconstruction techniques, the advantages of combining CS and parallel imaging, and sampling mask design problems are discussed in Section III. Numerous applications of CS in MRI due to its ability to improve imaging speed are reviewed in section IV. Clinical evaluations of some of the CS applications recently published are discussed in Section V. Section VI provides information on available open source software that could be used for CS implementations. PMID:24579643

  16. [Recent advances in newborn MRI].

    PubMed

    Morel, B; Hornoy, P; Husson, B; Bloch, I; Adamsbaum, C

    2014-07-01

    The accurate morphological exploration of the brain is a major challenge in neonatology that advances in magnetic resonance imaging (MRI) can now provide. MRI is the gold standard if an hypoxic ischemic pathology is suspected in a full term neonate. In prematures, the specific role of MRI remains to be defined, secondary to US in any case. We present a state of the art of hardware and software technical developments in MRI. The increase in magnetic field strength (3 tesla) and the emergence of new MRI sequences provide access to new information. They both have positive and negative consequences on the daily clinical data acquisition use. The semiology of brain imaging in full term newborns and prematures is more extensive and complex and thereby more difficult to interpret. The segmentation of different brain structures in the newborn, even very premature, is now available. It is now possible to dissociate the cortex and basal ganglia from the cerebral white matter, to calculate the volume of anatomical structures, which improves the morphometric quantification and the understanding of the normal and abnormal brain development. MRI is a powerful tool to analyze the neonatal brain. The relevance of the diagnostic contribution requires an adaptation of the parameters of the sequences to acquire and of the image processing methods. PMID:24837857

  17. MRI-Guided Electrophysiology Intervention

    PubMed Central

    Halperin, Henry R.; Kolandaivelu, Aravindan

    2010-01-01

    Catheter ablation is a first-line treatment for many cardiac arrhythmias and is generally performed under X-ray fluoroscopy guidance. However, current techniques for ablating complex arrhythmias such as atrial fibrillation and ventricular tachycardia are associated with sub-optimal success rates and prolonged radiation exposure. Pre-procedure 3-D magnetic resonance imaging (MRI) has improved understanding of the anatomic basis of complex arrhythmias and is being used for planning and guidance of ablation procedures. A particular strength of MRI compared to other imaging modalities is the ability to visualize ablation lesions. Post-procedure MRI is now being applied to assess ablation lesion location and permanence with the goal of identifying factors leading to procedure success and failure. In the future, intra-procedure real-time MRI, together with the ability to image complex 3-D arrhythmogenic anatomy and target additional ablation to regions of incomplete lesion formation, may allow for more successful treatment of even complex arrhythmias without exposure to ionizing radiation. Development of clinical grade MRI-compatible electrophysiology devices is required to transition intra-procedure MRI from preclinical studies to more routine use in patients. PMID:23908787

  18. Iron-Based Superparamagnetic Nanoparticle Contrast Agents for MRI of Infection and Inflammation

    PubMed Central

    Neuwelt, Alexander; Sidhu, Navneet; Hu, Chien-An A.; Mlady, Gary; Eberhardt, Steven C.; Sillerud, Laurel O.

    2015-01-01

    OBJECTIVE In this article, we summarize the progress to date on the use of superparamagnetic iron oxide nanoparticles (SPIONs) as contrast agents for MRI of inflammatory processes. CONCLUSION Phagocytosis by macrophages of injected SPIONs results in a prolonged shortening of both T2 and T2* leading to hypointensity of macrophage-infiltrated tissues in contrast-enhanced MR images. SPIONs as contrast agents are therefore useful for the in vivo MRI detection of macrophage infiltration, and there is substantial research and clinical interest in the use of SPION-based contrast agents for MRI of infection and inflammation. This technique has been used to identify active infection in patients with septic arthritis and osteomyelitis; importantly, the MRI signal intensity of the tissue has been found to return to its un-enhanced value on successful treatment of the infection. In SPION contrast-enhanced MRI of vascular inflammation, animal studies have shown decreased macrophage uptake in atherosclerotic plaques after treatment with statin drugs. Human studies have shown that both coronary and carotid plaques that take up SPIONs are more prone to rupture and that abdominal aneurysms with increased SPION uptake are more likely to grow. Studies of patients with multiple sclerosis suggest that MRI using SPIONs may have increased sensitivity over gadolinium for plaque detection. Finally, SPIONs have enabled the tracking and imaging of transplanted stem cells in a recipient host. PMID:25714316

  19. The Inclusion of Functional Connectivity Information into fMRI-based Neurofeedback Improves Its Efficacy in the Reduction of Cigarette Cravings.

    PubMed

    Kim, Dong-Youl; Yoo, Seung-Schik; Tegethoff, Marion; Meinlschmidt, Gunther; Lee, Jong-Hwan

    2015-08-01

    Real-time fMRI (rtfMRI) neurofeedback (NF) facilitates volitional control over brain activity and the modulation of associated mental functions. The NF signals of traditional rtfMRI-NF studies predominantly reflect neuronal activity within ROIs. In this study, we describe a novel rtfMRI-NF approach that includes a functional connectivity (FC) component in the NF signal (FC-added rtfMRI-NF). We estimated the efficacy of the FC-added rtfMRI-NF method by applying it to nicotine-dependent heavy smokers in an effort to reduce cigarette craving. ACC and medial pFC as well as the posterior cingulate cortex and precuneus are associated with cigarette craving and were chosen as ROIs. Fourteen heavy smokers were randomly assigned to receive one of two types of NF: traditional activity-based rtfMRI-NF or FC-added rtfMRI-NF. Participants received rtfMRI-NF training during two separate visits after overnight smoking cessation, and cigarette craving score was assessed. The FC-added rtfMRI-NF resulted in greater neuronal activity and increased FC between the targeted ROIs than the traditional activity-based rtfMRI-NF and resulted in lower craving score. In the FC-added rtfMRI-NF condition, the average of neuronal activity and FC was tightly associated with craving score (Bonferroni-corrected p = .028). However, in the activity-based rtfMRI-NF condition, no association was detected (uncorrected p > .081). Non-rtfMRI data analysis also showed enhanced neuronal activity and FC with FC-added NF than with activity-based NF. These results demonstrate that FC-added rtfMRI-NF facilitates greater volitional control over brain activity and connectivity and greater modulation of mental function than activity-based rtfMRI-NF. PMID:25761006

  20. Advanced Imaging of Adult Brain Tumors with MRI and PET

    Microsoft Academic Search

    Geoffrey S. Young; Jan Stauss; Srinivasan Mukundan

    2010-01-01

    We briefly review the major advanced MRI techniques used in clinical brain tumor imaging: diffusion-weighted imaging (DWI), perfusion-weighted imaging (DSC PWI), dynamic contrast-enhanced T1 permeability imaging (DCE T1P), diffusion-tensor imaging (DTI), and MR spectroscopy and spectroscopic imaging (MRS and MRSI, respectively). These techniques provide information about tumor cellularity (DWI), white matter invasion (DTI), metabolic derangement including hypoxia and necrosis (MRS),

  1. MRI of unusual lesions in the internal auditory canal

    Microsoft Academic Search

    A. Krainik; F. Cyna-Gorse; D. Bouccara; D. Cazals-Hatem; V. Vilgrain; A. Denys; A. Rey; O. Sterkers; Y. Menu

    2001-01-01

    We report the MRI findings of six unusual lesions of the internal auditory canal: three haemangiomas, one lipoma, one metastasis\\u000a and one traumatic neuroma. We compare the findings to those of 20 intracanalicular schwannomas. We noted the site and size\\u000a of the tumour, its signal intensity, borders and the homogeneity of enhancement were studied on T1-weighted images before\\u000a and after

  2. Benign prostate hyperplasia: evaluation of treatment response with DCE MRI

    Microsoft Academic Search

    J. T. Heverhagen; H. von Tengg-Kobligk; K. T. Baudendistel; G. Jia; H. Polzer; H. Henry; A. L. Levine; T. J. Rosol; M. V. Knopp

    2004-01-01

    Benign prostate hyperplasia (BPH) is a major disease and its non-surgical therapy a major area of interest. The purpose of this study was to establish perfusion parameters in beagles with BPH using dynamic contrast-enhanced (DCE) MRI and to investigate changes due to the effects of finasteride treatment. Twelve male beagles (mean age 4.4±0.9,years) were divided into a control and treatment

  3. The neural substrates of mindfulness: An fMRI investigation

    Microsoft Academic Search

    Victoria L. Ives-Deliperi; Mark Solms; Ernesta M. Meintjes

    2011-01-01

    “Mindfulness” is a capacity for heightened present-moment awareness that we all possess to a greater or lesser extent. Enhancing this capacity through training has been shown to alleviate stress and promote physical and mental well-being. As a consequence, interest in mindfulness is growing and so is the need to better understand it. This study employed functional magnetic resonance imaging (fMRI)

  4. Effectiveness of regional DTI measures in distinguishing Alzheimer's disease, MCI, and normal aging?

    PubMed Central

    Nir, Talia M.; Jahanshad, Neda; Villalon-Reina, Julio E.; Toga, Arthur W.; Jack, Clifford R.; Weiner, Michael W.; Thompson, Paul M.

    2013-01-01

    The Alzheimer's Disease Neuroimaging Initiative (ADNI) recently added diffusion tensor imaging (DTI), among several other new imaging modalities, in an effort to identify sensitive biomarkers of Alzheimer's disease (AD). While anatomical MRI is the main structural neuroimaging method used in most AD studies and clinical trials, DTI is sensitive to microscopic white matter (WM) changes not detectable with standard MRI, offering additional markers of neurodegeneration. Prior DTI studies of AD report lower fractional anisotropy (FA), and increased mean, axial, and radial diffusivity (MD, AxD, RD) throughout WM. Here we assessed which DTI measures may best identify differences among AD, mild cognitive impairment (MCI), and cognitively healthy elderly control (NC) groups, in region of interest (ROI) and voxel-based analyses of 155 ADNI participants (mean age: 73.5 ± 7.4; 90 M/65 F; 44 NC, 88 MCI, 23 AD). Both VBA and ROI analyses revealed widespread group differences in FA and all diffusivity measures. DTI maps were strongly correlated with widely-used clinical ratings (MMSE, CDR-sob, and ADAS-cog). When effect sizes were ranked, FA analyses were least sensitive for picking up group differences. Diffusivity measures could detect more subtle MCI differences, where FA could not. ROIs showing strongest group differentiation (lowest p-values) included tracts that pass through the temporal lobe, and posterior brain regions. The left hippocampal component of the cingulum showed consistently high effect sizes for distinguishing groups, across all diffusivity and anisotropy measures, and in correlations with cognitive scores. PMID:24179862

  5. Preclinical molecular imaging using PET and MRI.

    PubMed

    Wolf, Gunter; Abolmaali, Nasreddin

    2013-01-01

    Molecular imaging fundamentally changes the way we look at cancer. Imaging paradigms are now shifting away from classical morphological measures towards the assessment of functional, metabolic, cellular, and molecular information in vivo. Interdisciplinary driven developments of imaging methodology and probe molecules utilizing animal models of human cancers have enhanced our ability to non-invasively characterize neoplastic tissue and follow anti-cancer treatments. Preclinical molecular imaging offers a whole palette of excellent methodology to choose from. We will focus on positron emission tomography (PET) and magnetic resonance imaging (MRI) techniques, since they provide excellent and complementary molecular imaging capabilities and bear high potential for clinical translation. Prerequisites and consequences of using animal models as surrogates of human cancers in preclinical molecular imaging are outlined. We present physical principles, values and limitations of PET and MRI as molecular imaging modalities and comment on their high potential to non-invasively assess information on hypoxia, angiogenesis, apoptosis, gene expression, metabolism, and cell trafficking in preclinical cancer research. PMID:23179885

  6. MRI-based Preplanning Using CT and MRI Data Fusion in Patients With Cervical Cancer Treated With 3D-based Brachytherapy: Feasibility and Accuracy Study

    SciTech Connect

    Dolezel, Martin, E-mail: dolezelm@email.cz [Oncology Centre, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic) [Oncology Centre, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic); First Faculty of Medicine, Charles University, Prague (Czech Republic); Odrazka, Karel [Oncology Centre, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic) [Oncology Centre, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic); First Faculty of Medicine, Charles University, Prague (Czech Republic); Zizka, Jan [Department of Radiology, Charles University Teaching Hospital, Hradec Kralove (Czech Republic)] [Department of Radiology, Charles University Teaching Hospital, Hradec Kralove (Czech Republic); Vanasek, Jaroslav; Kohlova, Tereza; Kroulik, Tomas [Oncology Centre, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic)] [Oncology Centre, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic); Spitzer, Dusan; Ryska, Pavel [Department of Radiology, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic)] [Department of Radiology, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic); Tichy, Michal; Kostal, Milan [Department of Gynaecology, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic)] [Department of Gynaecology, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic); Jalcova, Lubica [Oncology Centre, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic)] [Oncology Centre, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic)

    2012-09-01

    Purpose: Magnetic resonance imaging (MRI)-assisted radiation treatment planning enables enhanced target contouring. The purpose of this study is to analyze the feasibility and accuracy of computed tomography (CT) and MRI data fusion for MRI-based treatment planning in an institution where an MRI scanner is not available in the radiotherapy department. Methods and Materials: The registration inaccuracy of applicators and soft tissue was assessed in 42 applications with CT/MRI data fusion. The absolute positional difference of the center of the applicators was measured in four different planes from the top of the tandem to the cervix. Any inaccuracy of registration of soft tissue in relation to the position of applicators was determined and dose-volume parameters for MRI preplans and for CT/MRI fusion plans with or without target and organs at risk (OAR) adaptation were evaluated. Results: We performed 6,132 measurements in 42 CT/MRI image fusions. Median absolute difference of the center of tandem on CT and MRI was 1.1 mm. Median distance between the center of the right ovoid on CT and MRI was 1.7 and 1.9 mm in the laterolateral and anteroposterior direction, respectively. Corresponding values for the left ovoid were 1.6 and 1.8 mm. Rotation of applicators was 3.1 Degree-Sign . Median absolute difference in position of applicators in relation to soft tissue was 1.93, 1.50, 1.05, and 0.84 mm in the respective transverse planes, and 1.17, 1.28, 1.27, and 1.17 mm in selected angular directions. The dosimetric parameters for organs at risk on CT/MRI fusion plans without OAR adaptation were significantly impaired whereas the target coverage was not influenced. Planning without target adaptation led to overdosing of the target volume, especially high-risk clinical target volume - D{sub 90} 88.2 vs. 83.1 (p < 0.05). Conclusions: MRI-based preplanning with consecutive CT/MRI data fusion can be safe and feasible, with an acceptable inaccuracy of soft tissue registration.

  7. Levels of emotional awareness and autism: An fMRI study

    Microsoft Academic Search

    Giorgia Silani; Geoffrey Bird; Rachel Brindley; Tania Singer; Chris Frith; Uta Frith

    2008-01-01

    Autism is associated with an inability to identify and distinguish one's own feelings. We assessed this inability using alexithymia and empathy questionnaires, and used fMRI to investigate brain activity while introspecting on emotion. Individuals with high functioning autism\\/Asperger syndrome (HFA\\/AS) were compared with matched controls. Participants rated stimuli from the International Affective Picture System twice, once according to the degree

  8. MRI characterization of cobalt dichloride-N-acetyl cysteine (C4) contrast agent marker for prostate brachytherapy

    NASA Astrophysics Data System (ADS)

    Lim, Tze Yee; Stafford, R. Jason; Kudchadker, Rajat J.; Sankaranarayanapillai, Madhuri; Ibbott, Geoffrey; Rao, Arvind; Martirosyan, Karen S.; Frank, Steven J.

    2014-05-01

    Brachytherapy, a radiotherapy technique for treating prostate cancer, involves the implantation of numerous radioactive seeds into the prostate. While the implanted seeds can be easily identified on a computed tomography image, distinguishing the prostate and surrounding soft tissues is not as straightforward. Magnetic resonance imaging (MRI) offers superior anatomical delineation, but the seeds appear as dark voids and are difficult to identify, thus creating a conundrum. Cobalt dichloride-N-acetyl-cysteine (C4) has previously been shown to be promising as an encapsulated contrast agent marker. We performed spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) measurements of C4 solutions with varying cobalt dichloride concentrations to determine the corresponding relaxivities, r1 and r2. These relaxation parameters were investigated at different field strengths, temperatures and orientations. T1 measurements obtained at 1.5 and 3.0 T, as well as at room and body temperature, showed that r1 is field-independent and temperature-independent. Conversely, the T2 values at 3.0 T were shorter than at 1.5 T, while the T2 values at body temperature were slightly higher than at room temperature. By examining the relaxivities with the C4 vials aligned in three different planes, we found no orientation-dependence. With these relaxation characteristics, we aim to develop pulse sequences that will enhance the C4 signal against prostatic stroma. Ultimately, the use of C4 as a positive contrast agent marker will encourage the use of MRI to obtain an accurate representation of the radiation dose delivered to the prostate and surrounding normal anatomical structures.

  9. MRI characterization of cobalt dichloride-N-acetyl cysteine (C4) contrast agent marker for prostate brachytherapy

    PubMed Central

    Lim, Tze Yee; Stafford, R Jason; Kudchadker, Rajat J; Sankaranarayanapillai, Madhuri; Ibbott, Geoffrey; Rao, Arvind; Martirosyan, Karen S; Frank, Steven J

    2014-01-01

    Brachytherapy, a radiotherapy technique for treating prostate cancer, involves the implantation of numerous radioactive seeds into the prostate. While the implanted seeds can be easily identified on a CT image, distinguishing the prostate and surrounding soft tissues is not as straightforward. Magnetic Resonance Imaging (MRI) offers superior anatomical delineation, but the seeds appear as dark voids and are difficult to identify, thus creating a conundrum. Cobalt dichloride-N-acetyl-cysteine (C4) has previously been shown to be promising as an encapsulated contrast agent marker. We performed spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) measurements of C4 solutions with varying cobalt dichloride concentrations to determine the corresponding relaxivities, r1 and r2. These relaxation parameters were investigated at different field strengths, temperatures and orientations. T1 measurements obtained at 1.5 T and 3.0 T, as well as at room and body temperature, showed that r1 is field-independent and temperature-independent. Conversely, the T2 values at 3.0 T were shorter than at 1.5 T, while the T2 values at body temperature were slightly higher than at room temperature. By examining the relaxivities with the C4 vials aligned in three different planes, we found no orientation-dependence. With these relaxation characteristics, we aim to develop pulse sequences that will enhance the C4 signal against prostatic stroma. Ultimately, the use of C4 as a positive contrast agent marker will encourage the use of MRI to obtain an accurate representation of the radiation dose delivered to the prostate and surrounding normal anatomical structures. PMID:24778352

  10. MRI monitoring of function, perfusion and viability in microembolized moderately ischemic myocardium.

    PubMed

    Do, Loi; Wilson, Mark W; Krug, Roland; Hetts, Steven W; Saeed, Maythem

    2015-08-01

    Assessment of microembolization after coronary interventions is clinically challenging, thus we longitudinally investigated microemboli effects on moderately ischemic myocardium using MRI and histopathology. Twenty-four pigs (8/group) were divided into: group I (no intervention), group II (45 min LAD occlusion) and group III (45 min LAD occlusion with microembolization). Cine, perfusion and delayed contrast enhanced MRI (DE-MRI), using 1.5T MRI, were used for assessment at 3 days and 5 weeks. Triphenyltetrazolium-chloride (TTC) and Masson-trichrome were used as gold standard references for macro and microscopic quantification of myocardial infarction (MI). Cine MRI showed differential increase in end systolic volume (1.3 ± 0.08 ml/kg group II and 1.6 ± 0.1 ml/kg group III) and decrease in ejection fraction (45 ± 2 and 36 ± 2 %, respectively) compared with controls at 3 days (2.1 ± 0.1 ml ESV and 50 ± 1 % EF, P < 0.05). At 5 weeks group III, but not II, showed persistent perfusion deficits, wall thinning in the LAD territory and compensatory hypertrophy in remote myocardium. DE-MRI MI at 3 days was significantly smaller in group II (3.3 ± 2.2 g) than III (9.8 ± 0.6 g), at 5 weeks, MI were smaller by 60 % (1.3 ± 0.9 g) and 22 % (7.7 ± 0.5 g), respectively. TTC MI was similar to DE-MRI in group II (1.6 ± 1.0 g) and III (9.2 ± 1.6 g), but not microscopy (2.8 ± 0.4 and 10.5 ± 1.5 g, respectively). The effects of moderate ischemia with and without microembolization on myocardium could be differentiated using multiple MRI sequences. MRI demonstrated that microemboli in moderately ischemic myocardium, but not solely ischemia, prolonged ventricular dysfunction, created perfusion deficits, poor infarct resorption and enhanced compensatory hypertrophy, while moderate ischemia alone caused minor LV changes. PMID:25951916

  11. 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.

  12. Gamma oscillations distinguish mere exposure from other likability effects.

    PubMed

    Kongthong, Nutchakan; Minami, Tetsuto; Nakauchi, Shigeki

    2014-02-01

    Repeated exposure to neutral stimuli enhances liking for those, which is called mere exposure effect (MEE) (Zajonc, 1968). Its behavioral effects have been extensively investigated. However, the mechanism by which it is generated remains unclear. To elucidate the neural mechanism of the MEE, we recorded electroencephalograms while subjects indicated their preferences for face stimuli with and without MEE induction. According to behavioral data, participants were divided into two groups, one with, and one without MEE tendency. In participants with an MEE tendency, gamma activity (40-60 [Hz]) in the parieto-occipital area was significantly weaker for exposed faces than unexposed ones, indicating a repetition-suppression effect. Gamma activity from sites exhibiting peak repetition-suppression effects was significantly weaker in theoretically genuine MEE trials than non-MEE trials, indicating that emotion processing might influence the MEE. These results suggest that existing theories regarding mechanisms underlying the MEE, namely, fluency misattribution and apprehensiveness reduction might not be mutually exclusive. Moreover, gamma activity might be a potential indicator to distinguish the MEE from other likability effects, at least in the case of human face stimuli. PMID:24389505

  13. Words matter: distinguishing "personalized medicine" and "biologically personalized therapeutics".

    PubMed

    Cherny, Nathan I; de Vries, Elisabeth G E; Emanuel, Linda; Fallowfield, Lesley; Francis, Prudence A; Gabizon, Alberto; Piccart, Martine J; Sidransky, David; Soussan-Gutman, Lior; Tziraki, Chariklia

    2014-12-01

    "Personalized medicine" has become a generic term referring to techniques that evaluate either the host or the disease to enhance the likelihood of beneficial patient outcomes from treatment interventions. There is, however, much more to personalization of care than just identifying the biotherapeutic strategy with the highest likelihood of benefit. In its new meaning, "personalized medicine" could overshadow the individually tailored, whole-person care that is at the bedrock of what people need and want when they are ill. Since names and definitional terms set the scope of the discourse, they have the power to define what personalized medicine includes or does not include, thus influencing the scope of the professional purview regarding the delivery of personalized care. Taxonomic accuracy is important in understanding the differences between therapeutic interventions that are distinguishable in their aims, indications, scope, benefits, and risks. In order to restore the due emphasis to the patient and his or her needs, we assert that it is necessary, albeit belated, to deconflate the contemporary term "personalized medicine" by taxonomizing this therapeutic strategy more accurately as "biologically personalized therapeutics" (BPT). The scope of truly personalized medicine and its relationship to biologically personalized therapeutics is described, emphasizing that the best of care must give due recognition and emphasis to both BPT and truly personalized medicine. PMID:25293984

  14. 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

  15. 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.

  16. Brute-Force Hyperpolarization for NMR and MRI.

    PubMed

    Hirsch, Matthew L; Kalechofsky, Neal; Belzer, Avrum; Rosay, Melanie; Kempf, James G

    2015-07-01

    Hyperpolarization (HP) of nuclear spins is critical for ultrasensitive nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). We demonstrate an approach for >1500-fold enhancement of key small-molecule metabolites: 1-(13)C-pyruvic acid, 1-(13)C-sodium lactate, and 1-(13)C-acetic acid. The (13)C solution NMR signal of pyruvic acid was enhanced 1600-fold at B = 1 T and 40 °C by pre-polarizing at 14 T and ?2.3 K. This "brute-force" approach uses only field and temperature to generate HP. The noted 1 T observation field is appropriate for benchtop NMR and near the typical 1.5 T of MRI, whereas high-field observation scales enhancement as 1/B. Our brute-force process ejects the frozen, solid sample from the low-T, high-B polarizer, passing it through low field (B < 100 G) to facilitate "thermal mixing". That equilibrates (1)H and (13)C in hundreds of milliseconds, providing (13)C HP from (1)H Boltzmann polarization attained at high B/T. The ejected sample arrives at a room-temperature, permanent magnet array, where rapid dissolution with 40 °C water yields HP solute. Transfer to a 1 T NMR system yields (13)C signals with enhancements at 80% of ideal for noted polarizing conditions. High-resolution NMR of the same product at 9.4 T had consistent enhancement plus resolution of (13)C shifts and J-couplings for pyruvic acid and its hydrate. Comparable HP was achieved with frozen aqueous lactate, plus notable enhancement of acetic acid, demonstrating broader applicability for small-molecule NMR and metabolic MRI. Brute-force avoids co-solvated free-radicals and microwaves that are essential to competing methods. Here, unadulterated samples obviate concerns about downstream purity and also exhibit slow solid-state spin relaxation, favorable for transporting HP samples. PMID:26098752

  17. DNA-BAR: Distinguisher Selection for DNA Barcoding

    Microsoft Academic Search

    B. DasGupta; K. M. Konwar; A. A. Shvartsman

    Summary: DNA-BAR is a software package for selecting DNA pro- bes (henceforth referred to as distinguishers) that can be used in genomic-based identification of microorganisms. Given the genomic sequences of the microorganisms, DNA-BAR finds a near-minimum number of distinguishers yielding a distinct hybridization pattern for each microorganism. Selected distinguishers satisfy user specified bounds on length, melting temperature, and GC content,

  18. DNA-BAR: distinguisher selection for DNA barcoding

    Microsoft Academic Search

    Bhaskar Dasgupta; Kishori M. Konwar; Ion I. Mandoiu; Alexander A. Shvartsman

    2005-01-01

    Summary: DNA-BAR is a software package for selecting DNA probes (henceforth referred to as distinguishers) that can be used in genomic- based identification of microorganisms. Given the genomic sequences of the microorganisms, DNA-BAR finds a near-minimum number of distinguishers yielding a distinct hybridization pattern for each micro- organism. Selected distinguishers satisfy user specified bounds on length, melting temperature and GC

  19. DNA-BAR: distinguisher selection for DNA barcoding.

    PubMed

    DasGupta, B; Konwar, K M; Mandoiu, I I; Shvartsman, A A

    2005-08-15

    DNA-BAR is a software package for selecting DNA probes (henceforth referred to as distinguishers) that can be used in genomic-based identification of microorganisms. Given the genomic sequences of the microorganisms, DNA-BAR finds a near-minimum number of distinguishers yielding a distinct hybridization pattern for each microorganism. Selected distinguishers satisfy user specified bounds on length, melting temperature and GC content, as well as redundancy and cross-hybridization constraints. PMID:15961439

  20. Frequency-Offset Cartesian Feedback for MRI Power Amplifier Linearization

    PubMed Central

    Zanchi, Marta Gaia; Stang, Pascal; Kerr, Adam; Pauly, John Mark; Scott, Greig Cameron

    2011-01-01

    High-quality magnetic resonance imaging (MRI) requires precise control of the transmit radio-frequency field. In parallel excitation applications such as transmit SENSE, high RF power linearity is essential to cancel aliased excitations. In widely-employed class AB power amplifiers, gain compression, cross-over distortion, memory effects, and thermal drift all distort the RF field modulation and can degrade image quality. Cartesian feedback (CF) linearization can mitigate these effects in MRI, if the quadrature mismatch and DC offset imperfections inherent in the architecture can be minimized. In this paper, we present a modified Cartesian feedback technique called “frequency-offset Cartesian feedback” (FOCF) that significantly reduces these problems. In the FOCF architecture, the feedback control is performed at a low intermediate frequency rather than DC, so that quadrature ghosts and DC errors are shifted outside the control bandwidth. FOCF linearization is demonstrated with a variety of typical MRI pulses. Simulation of the magnetization obtained with the Bloch equation demonstrates that high-fidelity RF reproduction can be obtained even with inexpensive class AB amplifiers. Finally, the enhanced RF fidelity of FOCF over CF is demonstrated with actual images obtained in a 1.5 T MRI system. PMID:20959264

  1. NOMINATION FORM COLLEGE OF AGRICULTURAL SCIENCES DISTINGUISHED RESEARCH ASSOCIATE AWARD

    E-print Network

    NOMINATION FORM COLLEGE OF AGRICULTURAL SCIENCES DISTINGUISHED RESEARCH ASSOCIATE AWARD Nominee in performing his or her responsibilities?" Show evidence of excellence in: productivity, efficiency, initiative

  2. Advanced MRI and PET imaging for assessment of treatment response in patients with gliomas.

    PubMed

    Dhermain, Frederic G; Hau, Peter; Lanfermann, Heinrich; Jacobs, Andreas H; van den Bent, Martin J

    2010-09-01

    Imaging techniques are important for accurate diagnosis and follow-up of patients with gliomas. T1-weighted MRI, with or without gadolinium, is the gold standard method. However, this technique only reflects biological activity of the tumour indirectly by detecting the breakdown of the blood-brain barrier. Therefore, especially for low-grade glioma or after treatment, T1-weighted MRI enhanced with gadolinium has substantial limitations. Development of more advanced imaging methods to improve outcomes for individual patients is needed. New imaging methods based on MRI and PET can be employed in various stages of disease to target the biological activity of the tumour cells (eg, increased uptake of aminoacids or nucleoside analogues), the changes in diffusivity through the interstitial space (diffusion-weighted MRI), the tumour-induced neovascularisation (perfusion-weighted MRI or contrast-enhanced MRI, or increased uptake of aminoacids in endothelial wall), and the changes in concentrations of metabolites (magnetic resonance spectroscopy). These techniques have advantages and disadvantages, and should be used in conjunction to best help individual patients. Advanced imaging techniques need to be validated in clinical trials to ensure standardisation and evidence-based implementation in routine clinical practice. PMID:20705518

  3. PS1-15: Pre-filling Breast MRI Abstraction Forms Using Natural Language Processing

    PubMed Central

    Gao, Hongyuan; Wernli, Karen

    2014-01-01

    Background/Aims Information in breast MRI reports is valuable for breast cancer research, but these data are only available in free-text reports and require resource-intensive manual abstraction. We developed and tested a Natural Language Processing (NLP) algorithm to extract information and pre-fill abstraction form from free-text breast MRI reports. Methods We identified 465 reports for women receiving breast MRI at Group Health between 2010–2012. We developed an NLP algorithm in SAS v9.2. The algorithm extracts information of reading radiologist, laterality, parenchymal enhancement, whether computer-aided technique is used, comparison exams, clinical indications and assessment from breast MRI reports. The NLP results are compared with manual abstraction from an experienced abstractor. Results The algorithm correctly extracts reading radiologist, laterality and whether computer-aided technique for all 465 breast MRI reports, except 1 report with inconsistent information on laterality itself. It correctly extracts 83% of 465 reports for assessment for right breast and 92% for assessment for left breast. Unstable gold standard impedes performance of the NLP algorithm for extracting parenchymal enhancement and clinical indications. There is no gold standard to show NLP performance for comparison exams yet. Conclusions This NLP algorithm holds promise for rapid, accurate extraction of information from free-text breast MRI reports. Manual review will be faster and more accurate due to the pre-filling of the abstraction form.

  4. Iron-based superparamagnetic nanoparticle contrast agents for MRI of infection and inflammation.

    PubMed

    Neuwelt, Alexander; Sidhu, Navneet; Hu, Chien-An A; Mlady, Gary; Eberhardt, Steven C; Sillerud, Laurel O

    2015-03-01

    OBJECTIVE. In this article, we summarize the progress to date on the use of superparamagnetic iron oxide nanoparticles (SPIONs) as contrast agents for MRI of inflammatory processes. CONCLUSION. Phagocytosis by macrophages of injected SPIONs results in a prolonged shortening of both T2 and T2* leading to hypointensity of macrophage-infiltrated tissues in contrast-enhanced MR images. SPIONs as contrast agents are therefore useful for the in vivo MRI detection of macrophage infiltration, and there is substantial research and clinical interest in the use of SPION-based contrast agents for MRI of infection and inflammation. This technique has been used to identify active infection in patients with septic arthritis and osteomyelitis; importantly, the MRI signal intensity of the tissue has been found to return to its unenhanced value on successful treatment of the infection. In SPION contrast-enhanced MRI of vascular inflammation, animal studies have shown decreased macrophage uptake in atherosclerotic plaques after treatment with statin drugs. Human studies have shown that both coronary and carotid plaques that take up SPIONs are more prone to rupture and that abdominal aneurysms with increased SPION uptake are more likely to grow. Studies of patients with multiple sclerosis suggest that MRI using SPIONs may have increased sensitivity over gadolinium for plaque detection. Finally, SPIONs have enabled the tracking and imaging of transplanted stem cells in a recipient host. PMID:25714316

  5. Diffusion-Weighted MRI in Intrahepatic Bile Duct Adenoma Arising from the Cirrhotic Liver

    PubMed Central

    An, Chansik; Choi, Yoon Jung

    2013-01-01

    A 64-year-old male patient with liver cirrhosis underwent a CT study for hepatocellular carcinoma surveillance, which demonstrated a 1.4-cm hypervascular subcapsular tumor in the liver. On gadoxetic acid-enhanced MRI, the tumor showed brisk arterial enhancement and persistent hyperenhancement in the portal phase, but hypointensity in the hepatobiliary phase. On diffusion-weighted MRI, the tumor showed an apparent diffusion coefficient twofold greater than that of the background liver parenchyma, which suggested that the lesion was benign. The histologic diagnosis was intrahepatic bile duct adenoma with alcoholic liver cirrhosis. PMID:24043970

  6. JOB OPENINGS MRI technical developments and applications

    E-print Network

    Duong, Timothy Q.

    and Bruker) 2) MRI applications in stroke, TBI and retinal diseases in animals and humans Qualifications JOB OPENINGS MRI technical developments and applications in animals and humans Research Imaging Institute, MRI Division, University of Texas Health Science Center at San Antonio Positions

  7. Screening for breast cancer with MRI

    Microsoft Academic Search

    Elizabeth A Morris

    2003-01-01

    Breast MRI has emerged as an extremely powerful tool in breast imaging. The use of breast MRI for cancer detection has the potential to change our current algorithms in the detection of breast cancer. By being able to detect cancer that is occult on conventional imaging, such as mammography and sonography, MRI can detect early breast cancer that was previously

  8. Cervical Spine MRI in Abused Infants.

    ERIC Educational Resources Information Center

    Feldman, Kenneth W.; And Others

    1997-01-01

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

  9. MRI Grant Program: Expert Tips & Tricks

    E-print Network

    Wang, Bing

    MRI Grant Program: Expert Tips & Tricks to Nab Expensive Instrumentation WHITE PAPER Sponsored by: #12;White Paper: MRI Grant Program: Expert Tips & Tricks to Nab Expensive Instrumentation Principal Investigators Association | www.principalinvestigators.org 2 White Paper -- "MRI Grant Program: Expert Tips

  10. MRI Dispersion for a Helicon Plasma

    Microsoft Academic Search

    Courtney Kaita; Hantao Ji; Cami Collins

    2009-01-01

    The magnetorotational instability (MRI) is a basic MHD instability that occurs when a weak magnetic field is present in a differentially rotating disk. MRI is a likely reason for fast angular momentum transport in astrophysical accretion disks. A cohesive understanding of MRI with a range of plasma parameters pertaining to the wide variety of accretion disk systems has become an

  11. Functional magnetic resonance imaging (fMRI) \\

    Microsoft Academic Search

    David D. Cox; Robert L. Savoy

    Traditional (univariate) analysis of functional MRI (fMRI) data relies exclusively on the information contained in the time course of individual voxels. Multivariate analyses can take advantage of the information contained in activity patterns across space, from multiple voxels. Such analyses have the potential to greatly expand the amount of information extracted from fMRI data sets. In the present study, multivariate

  12. Functional MRI Using Regularized Parallel Imaging Acquisition

    E-print Network

    Functional MRI Using Regularized Parallel Imaging Acquisition Fa-Hsuan Lin,1* Teng-Yi Huang,1,2 Nan. Kwong1 Parallel MRI techniques reconstruct full-FOV images from un- dersampled k-space data by using the uncorrelated information from RF array coil elements. One disadvantage of parallel MRI is that the image signal

  13. Open MRI-Guided Neurosurgery

    Microsoft Academic Search

    V. Seifert; M. Zimmermann; C. Trantakis; H.-E. Vitzthum; K. Kühnel; A. Raabe; F. Bootz; J.-P. Schneider; F. Schmidt; J. Dietrich

    1999-01-01

    Summary  ?Objectives. A number of different image-guided surgical techniques have been developed during the past decade. None of these methods\\u000a can provide the surgeon with information about the dynamic changes that occur intra-operatively.\\u000a \\u000a ?Material and Method. The first vertical open 0.5 T MRI-scanner for intra-operative MRI-guided neurosurgery in Germany was installed at the University\\u000a of Leipzig during the summer 1996. Since

  14. Albert Einstein Distinguished Educators Fellowship Act of 1994. Report To Accompany S. 2104. 103D Congress, 2d Session, Senate.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. Senate Committee on Energy and Natural Resources.

    This document contains the text of the "Albert Einstein Distinguished Educators Fellowship Act of 1994" (S. 2104) along with related analysis. The bill establishes a Department of Energy (DOE) fellowship program for math and science teachers that provides them opportunities to work at DOE labs in order to enhance coordination and communication…

  15. Telling truth from lie in individual subjects with fast event-related fMRI.

    PubMed

    Langleben, Daniel D; Loughead, James W; Bilker, Warren B; Ruparel, Kosha; Childress, Anna Rose; Busch, Samantha I; Gur, Ruben C

    2005-12-01

    Deception is a clinically important behavior with poorly understood neurobiological correlates. Published functional MRI (fMRI) data on the brain activity during deception indicates that, on a multisubject group level, lie is distinguished from truth by increased prefrontal and parietal activity. These findings are theoretically important; however, their applied value will be determined by the accuracy of the discrimination between single deceptive and truthful responses in individual subjects. This study presents the first quantitative estimate of the accuracy of fMRI in conjunction with a formal forced-choice paradigm in detecting deception in individual subjects. We used a paradigm balancing the salience of the target cues to elicit deceptive and truthful responses and determined the accuracy of this model in the classification of single lie and truth events. The relative salience of the task cues affected the net activation associated with lie in the superior medial and inferolateral prefrontal cortices. Lie was discriminated from truth on a single-event level with an accuracy of 78%, while the predictive ability expressed as the area under the curve (AUC) of the receiver operator characteristic curve (ROC) was 85%. Our findings confirm that fMRI, in conjunction with a carefully controlled query procedure, could be used to detect deception in individual subjects. Salience of the task cues is a potential confounding factor in the fMRI pattern attributed to deception in forced choice deception paradigms. PMID:16161128

  16. A fluorescent, paramagnetic and PEGylated gold/silica nanoparticle for MRI, CT and fluorescence imaging

    PubMed Central

    van Schooneveld, Matti M.; Cormode, David P.; Koole, Rolf; van Wijngaarden, J. Timon; Calcagno, Claudia; Skajaa, Torjus; Hilhorst, Jan; ’t Hart, Dannis C.; Fayad, Zahi A.; Mulder, Willem J. M.; Meijerink, Andries

    2013-01-01

    An important challenge in medical diagnostics is to design all-in-one contrast agents that can be detected with multiple techniques such as magnetic resonance imaging (MRI), X-ray computed tomography (CT), positron emission tomography (PET), single photon emission tomography (SPECT) or fluorescence imaging (FI). Although many dual labeled agents have been proposed, mainly for combined MRI/FI, constructs for three imaging modalities are scarce. Here gold/silica nanoparticles with a poly(ethylene glycol), paramagnetic and fluorescent lipid coating were synthesized, characterized and applied as trimodal contrast agents to allow for nanoparticle-enhanced imaging of macrophage cells in vitro via MRI, CT and FI, and mice livers in vivo via MRI and CT. This agent can be a useful tool in a multitude of applications, including cell tracking and target-specific molecular imaging, and is a step in the direction of truly multi-modal imaging. PMID:20812290

  17. MRI of the lung gas-space at very low-field using hyperpolarized noble gases

    NASA Technical Reports Server (NTRS)

    Venkatesh, Arvind K.; Zhang, Adelaide X.; Mansour, Joey; Kubatina, Lyubov; Oh, Chang Hyun; Blasche, Gregory; Selim Unlu, M.; Balamore, Dilip; Jolesz, Ferenc A.; Goldberg, Bennett B.; Albert, Mitchell S.

    2003-01-01

    In hyperpolarized (HP) noble-gas magnetic resonance imaging, large nuclear spin polarizations, about 100,000 times that ordinarily obtainable at thermal equilibrium, are created in 3He and 129Xe. The enhanced signal that results can be employed in high-resolution MRI studies of void spaces such as in the lungs. In HP gas MRI the signal-to-noise ratio (SNR) depends only weakly on the static magnetic field (B(0)), making very low-field (VLF) MRI possible; indeed, it is possible to contemplate portable MRI using light-weight solenoids or permanent magnets. This article reports the first in vivo VLF MR images of the lungs in humans and in rats, obtained at a field of only 15 millitesla (150 Gauss).

  18. Distinguishing Samples of Spoken Korean from Rhythmic and Regional Competitors.

    ERIC Educational Resources Information Center

    Bond, Z. S.; Stockmal, Verna

    2002-01-01

    Examined characteristics of the acoustic signature of languages in connection with identification of the target language, Korean. In one experiment, listeners were asked to distinguish spoken samples of Korean from competitor languages sharing syllable based rhythm. In another, listeners attempted to distinguish Korean from languages spoken in the…

  19. Distinguishing Mathematics Notation from English Text using Computational Geometry

    E-print Network

    Baird, Henry S.

    Distinguishing Mathematics Notation from English Text using Computational Geometry Derek M. Drake, CSE Dept. Bethlehem, PA 18015 USA baird@cse.lehigh.edu Abstract A trainable method for distinguishing between mathe- matics notation and natural language (here, English) in images of textlines, using

  20. Computerderived Nuclear Features Distinguish Malignant from Benign Breast Cytology.

    E-print Network

    Street, Nick

    previously encountered. Materials and Methods Patients and Aspirate The benign and malignant cell samples1 Wolberg Computer­derived Nuclear Features Distinguish Malignant from Benign Breast Cytology features. These features are then tested to distinguish between benign and malignant breast cytology

  1. John Glenn: Presented with NASA Distinguished Service Medal

    NASA Technical Reports Server (NTRS)

    1963-01-01

    John Glenn tours with his family, meets JFK and is presented with the NASA distinguished Service Medal. From: The John Glenn Story: Summary of astronaut John Glenn's flying career, from naval aviation training to space flight. The Mercury project is featured as John Glenn flies the Friendship 7 spacecraft. President John F. Kennedy presents the NASA Distinguished service Medal to Astronaut John Glenn.

  2. The Rebound Attack and Subspace Distinguishers: Application to Whirlpool

    E-print Network

    The Rebound Attack and Subspace Distinguishers: Application to Whirlpool Mario Lamberger1 , Florian the rebound attack as a variant of differen- tial cryptanalysis on hash functions and apply it to the hash as generalizations of near-collision resistance. Finally, we present distinguishers based on the rebound attack

  3. The Graduate School Distinguished Alumni Award Nominations Due

    E-print Network

    Ferrari, Silvia

    The Graduate School Distinguished Alumni Award Nominations Due Friday, November 30, 2012 Description of the Award The Graduate School Distinguished Alumni Award is given annually to a graduate the Graduate School Hooding Ceremony. Eligibility Criteria Nominees must have received a Ph.D. from Duke

  4. The Washington State Distinguished Professorship Program. Status Report.

    ERIC Educational Resources Information Center

    Washington State Higher Education Coordinating Board, Olympia.

    Since its inception in 1985, and through 1992, Washington state's Distinguished Professorship Program has succeeded in establishing 32 prestigious professorships at its four-year institutions with 3 more in process. Also in 1985, the state legislature enacted the Distinguished Professorship Trust Fund Program to strengthen partnerships between…

  5. Astronaut Alan Shepard receives MASA Distinguished Service award

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Astronaut Alan B. Shepard recieves the NASA Distinguished Service Award from President John F. Kennedy in May 1961, days after his history making MR-3 flight (31387); Alan Shepard and his wife wave to the crowd after Shepard received the NASA Distinguished Service Award from President John F. Kennedy (31388).

  6. Distinguished Graduate Student Fellowship Award Year 2012-2013

    E-print Network

    Saldin, Dilano

    Distinguished Graduate Student Fellowship Award Year 2012-2013 Information Sheet Description graduate students. If awarded, the fellowship recipient receives: $12,332 stipend for the Academic Year for or receive a Distinguished Graduate Student Fellowship. For questions regarding this fellowship application

  7. A New Statistical Distinguisher for the Shrinking Generator

    E-print Network

    A New Statistical Distinguisher for the Shrinking Generator Jovan Dj. Goli#19;c and Renato Menicocci Abstract The shrinking generator is a well-known keystream generator composed of two linear random sequence. Previously proposed statistical distinguishers for the shrinking generator are based

  8. NOMINATION FORM 2010 Distinguished Texan in Agriculture Award

    E-print Network

    NOMINATION FORM 2010 Distinguished Texan in Agriculture Award Texas A&M AgriLife The Texas A/her contributions on behalf of the Texas agricultural industry and community (information may be submitted:__________________________________________________________ ________________________________________________________________________ RETURN NOMINATIONS TO 2010 Distinguished Texan in Agriculture Selection Advisory Committee c/o Office

  9. 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…

  10. Value of Fused 18F-Choline-PET/MRI to Evaluate Prostate Cancer Relapse in Patients Showing Biochemical Recurrence after EBRT: Preliminary Results

    PubMed Central

    Piccardo, Arnoldo; Paparo, Francesco; Picazzo, Riccardo; Naseri, Mehrdad; Ricci, Paolo; Marziano, Andrea; Bacigalupo, Lorenzo; Biscaldi, Ennio; Rollandi, Gian Andrea; Grillo-Ruggieri, Filippo; Farsad, Mohsen

    2014-01-01

    Purpose. We compared the accuracy of 18F-Choline-PET/MRI with that of multiparametric MRI (mMRI), 18F-Choline-PET/CT, 18F-Fluoride-PET/CT, and contrast-enhanced CT (CeCT) in detecting relapse in patients with suspected relapse of prostate cancer (PC) after external beam radiotherapy (EBRT). We assessed the association between standard uptake value (SUV) and apparent diffusion coefficient (ADC). Methods. We evaluated 21 patients with biochemical relapse after EBRT. Patients underwent 18F-Choline-PET/contrast-enhanced (Ce)CT, 18F-Fluoride-PET/CT, and mMRI. Imaging coregistration of PET and mMRI was performed. Results. 18F-Choline-PET/MRI was positive in 18/21 patients, with a detection rate (DR) of 86%. DRs of 18F-Choline-PET/CT, CeCT, and mMRI were 76%, 43%, and 81%, respectively. In terms of DR the only significant difference was between 18F-Choline-PET/MRI and CeCT. On lesion-based analysis, the accuracy of 18F-Choline-PET/MRI, 18F-Choline-PET/CT, CeCT, and mMRI was 99%, 95%, 70%, and 85%, respectively. Accuracy, sensitivity, and NPV of 18F-Choline-PET/MRI were significantly higher than those of both mMRI and CeCT. On whole-body assessment of bone metastases, the sensitivity of 18F-Choline-PET/CT and 18F-Fluoride-PET/CT was significantly higher than that of CeCT. Regarding local and lymph node relapse, we found a significant inverse correlation between ADC and SUV-max. Conclusion. 18F-Choline-PET/MRI is a promising technique in detecting PC relapse. PMID:24877053

  11. Diffusion-weighted MRI hyperintensity patterns differentiate CJD from other rapid dementias

    PubMed Central

    Vitali, P.; Maccagnano, E.; Caverzasi, E.; Henry, R.G.; Haman, A.; Torres-Chae, C.; Johnson, D.Y.; Miller, B.L.

    2011-01-01

    Background: Diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) MRI have high sensitivity and specificity for Creutzfeldt-Jakob disease (CJD). No studies, however, have demonstrated how MRI can distinguish CJD from nonprion causes of rapidly progressive dementia (npRPD). We sought to determine the diagnostic accuracy of MRI for CJD compared to a cohort of npRPD subjects. Methods: Two neuroradiologists blinded to diagnosis assessed DWI and FLAIR images in 90 patients with npRPD (n = 29) or prion disease (sporadic CJD [sCJD], n = 48, or genetic prion disease [familial CJD, n = 6, and Gerstmann-Sträussler-Scheinker, n = 7]). Thirty-one gray matter regions per hemisphere were assessed for abnormal hyperintensities. The likelihood of CJD was assessed using our previously published criteria. Results: Gray matter hyperintensities (DWI > FLAIR) were found in all sCJD cases, with certain regions preferentially involved, but never only in limbic regions, and rarely in the precentral gyrus. In all sCJD cases with basal ganglia or thalamic DWI hyperintensities, there was associated restricted diffusion (apparent diffusion coefficient [ADC] map). This restricted diffusion, however, was not seen in any npRPD cases, in whom isolated limbic hyperintensities (FLAIR > DWI) were common. One reader's sensitivity and specificity for sCJD was 94% and 100%, respectively, the other's was 92% and 72%. After consensus review, the readers' combined MRI sensitivity and specificity for sCJD was 96% and 93%, respectively. Familial CJD had overlapping MRI features with sCJD. Conclusions: The pattern of FLAIR/DWI hyperintensity and restricted diffusion can differentiate sCJD from other RPDs with a high sensitivity and specificity. MRI with DWI and ADC should be included in sCJD diagnostic criteria. New sCJD MRI criteria are proposed. PMID:21471469

  12. Combined DCE-MRI and DW-MRI for Predicting Breast Cancer Pathological Response After the First Cycle of Neoadjuvant Chemotherapy

    PubMed Central

    Li, Xia; Abramson, Richard G.; Arlinghaus, Lori R.; Kang, Hakmook; Chakravarthy, A. Bapsi; Abramson, Vandana G.; Farley, Jaime; Mayer, Ingrid A.; Kelley, Mark C.; Meszoely, Ingrid M.; Means-Powell, Julie; Grau, Ana M.; Sanders, Melinda; Yankeelov, Thomas E.

    2015-01-01

    Objectives To determine if combined measurements from dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) and diffusion weighted MRI (DW-MRI), obtained before and after the first cycle of neoadjuvant chemotherapy (NAC), are superior to single parameter measurements for predicting pathological complete response (pCR) in breast cancer patients. Materials and Methods Patients with Stage II/III breast cancer were enrolled in an IRB-approved study in which 3T DCE- and DW-MRI data were acquired before (n = 37) and after one cycle (n = 33) of NAC. Estimates of Ktrans, ve, vp, and kep (= Ktrans/ve) were generated from the DCE-MRI data using the Extended Tofts-Kety (ETK) model. The apparent diffusion coefficient (ADC) was estimated from the DW-MRI data. The derived parameter kep/ADC was compared to single parameter measurements for its ability to predict pCR after the first cycle of NAC. Results kep/ADC after the first cycle of NAC discriminated patients who went on to achieve a pCR (P < 0.001), and achieved a sensitivity, specificity, positive predictive value, and area under the receiver operator curve (AUC) of 0.92, 0.75, 0.69, and 0.86, respectively. These values were superior to the single parameters kep (AUC = 0.77) and ADC (AUC = 0.81). The AUCs between kep/ADC and kep were significantly different based on the bootstrapped 95% CIs (0.0062, 0.20), while the AUCs between kep/ADC and ADC trended towards significance (?0.12, 0.24). Conclusions A combined analysis of DCE-MRI and DW-MRI parameters was superior to single-parameter measurements for predicting pCR after the first cycle of NAC. PMID:25360603

  13. PET/MRI for Preoperative Planning in Patients with Soft Tissue Sarcoma: A Technical Report of Two Patients.

    PubMed

    Loft, Annika; Jensen, Karl Erik; Löfgren, Johan; Daugaard, Søren; Petersen, Michael M

    2013-01-01

    Clinical positron emission tomography (PET)/magnetic resonance imaging (MRI) acquisition protocols may improve the evaluation of soft tissue sarcomas (STS) prior to surgical planning. We examined two patients with lower extremity STS using a Siemens Biograph mMR PET/MRI scanner and the glucose analogue 18F-fluoro-deoxyglucose (FDG). We investigated clinically relevant tumor volumes and evaluated the relations to skeletal periosteum and nerve bundles. The patient scans suggest that FDG PET/MRI improved the edge detection, and invasion of tumor tissue into important adjacent anatomical structures can be evaluated. FDG PET/MRI also provided additional information compared to conventional Gadolinium enhanced MR imaging. The findings were proven by subsequent pathological examination of the resected tumor tissue. In the future, clinical FDG PET/MRI may be an important modality for preoperative planning, including radiation therapy planning in patients with STS. PMID:24368921

  14. Ellipsoidal harmonic (Lame) MRI shims

    Microsoft Academic Search

    S. Crozier; L. K. Forbes; M. Brideson

    2002-01-01

    Ellipsoidal harmonics are presented as a basis function set for the design of shim coils for magnetic resonance imaging (MRI) or spectroscopy. MR shim coils may be either superconductive or resistive. Ellipsoidal harmonics form an orthogonal set over an ellipsoid and hence are appropriate in circumstances where the imaging or spectroscopic region of a magnet more closely conforms to an

  15. 16 Diffusion Tensor MRI Visualization

    E-print Network

    Utah, University of

    16 Diffusion Tensor MRI Visualization 16.1 Introduction Diffusion Tensor Magnetic Resonance Imaging the diffusion of water molecules. The direction of fastest diffusion is aligned with fiber orientation in a pattern that can be numerically modeled by a diffusion tensor. DTI is the only modality for noninva

  16. Improvements in Low Field MRI

    E-print Network

    Ogier, Stephen E

    2013-02-01

    for this system, which has a static magnetic field in an unconventional direction. The stronger gradient allows for the selection of thin slices with RF pulses of reasonable length. The third effort was in low-noise RF coils. Typical MRI systems are enclosed...

  17. MRI Biosensors: A Short Primer

    PubMed Central

    Louie, Angelique

    2013-01-01

    Interest in Magnetic Resonance Imaging (MRI) contrast agents for molecular imaging of biological function experienced a surge of excitement approximately 20 years ago with the development of the first activatable contrast agents that could act as biosensors and turn “on” in response to a specific biological activity. This brief tutorial, based on a short course lecture from the 2011 ISMRM meeting, provides an overview of underlying principles governing the design of biosensing contrast agents. We describe mechanisms by which a magnetic resonance imaging (MRI) contrast agent can be made into a sensor for both T1 and T2 types contrast agents. Examples of biological activities that can interact with a contrast agent are discussed using specific examples from the recent literature to illustrate the primary mechanisms of action that have been utilized to achieve activation. MRI sensors for pH, ion binding, enzyme cleavage, and oxidation-reduction are presented. This article is not meant to be an exhaustive review, but an illustrative primer to explain how activation can be achieved for an MRI contrast agent. Chemical exchange saturation transfer (CEST) is not covered as these agents were covered in a separate lecture. PMID:23996662

  18. Award for Distinguished Career Contributions to Education and Training and Award for Distinguished Contributions to Education and Training

    ERIC Educational Resources Information Center

    American Psychologist, 2009

    2009-01-01

    The Distinguished Contributions to Education and Training awards are given by the Board of Educational Affairs in recognition of the efforts of psychologists who have made distinguished contributions to education and training, who have produced imaginative innovations, or who have been involved in the developmental phases of programs in education…

  19. [Stress cardiac MRI in management of ischemic heart disease].

    PubMed

    Russel, S; Darmon, S; Vermillet, A; Haziza, F

    2014-11-01

    Stress magnetic cardiac resonance imaging (MRI) development is in progress. Many cardiac imaging technics already known are completed by this safe radiation free exam with a short time acquisition (30minutes) and a good diagnostic performance in particular for patients with three vessels coronary artery diseases. Best indication concerns symptomatic patients unable to exercise with intermediate or high pretest probability. Pharmacological heart stress can be induced with vasodilatators or dobutamine to identify the presence and extent of myocardial ischemia, with high precision to guide coronary vessels revascularization. MRI gives many other interesting informations like heart anatomy, left ventricular function. Myocardial viability can be assessed with study of late gadolinium enhancement or analysis of contractile reserve with low dose of dobutamine. PMID:25281219

  20. Fibrous tumours of the ovary: aetiologies and MRI features.

    PubMed

    Montoriol, P-F; Mons, A; Da Ines, D; Bourdel, N; Tixier, L; Garcier, J M

    2013-12-01

    The ovaries can be affected by a vast variety of tumours, which may be benign or malignant, solid or cystic. Although ultrasonography is often the first examination performed in the evaluation of gynaecological conditions, magnetic resonance imaging is nowadays the most accurate imaging technique in the characterization of ovarian masses. Once the ovarian origin of a pelvic mass has been determined, the detection of any fibrous component within the lesion significantly reduces the spectrum of aetiologies that should be considered. Fibrotic tissue usually displays marked low-signal intensity on T2-weighted sequences at MRI, and enhancement is mostly moderate after intravenous administration of gadolinium chelates. This review aims to provide the main diagnoses to consider at MRI whenever an ovarian tumour, both purely solid or solid and cystic, contains a fibrous component, even if minimally abundant. The corresponding key imaging features are provided. PMID:23937826