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Purpose: To demonstrate the feasibility of motion compensating diffusion gradient schemes in the acquisition of quality diffusion tensor images (DTI) of the brain during continuous gross head motion. Methods: Five healthy subjects were scanned using a clinical 3 T MRI with and without continuous head motion. For one volunteer, DTI data was acquired using standard (M0) diffusion‐weighted (DW) gradients, and first (M1) and second (M2) order gradient schemes that were previously developed for use in cardiac DTI. In four additional volunteers, DTI data was acquired with M0 and M2 gradients. DTI parameters were calculated and compared with established retrospective motion corrections. Results: In the absence of motion, DTI parameters calculated from M0, M1, and M2 data were consistent. In the presence of motion, up to 44% of DW images acquired with M0 gradients were corrupted by signal dropout, compared to 0% of the M2 images. In voxelwise comparisons, DTI parameters calculated using motion‐M0 data were elevated compared to reference data. Retrospective corrections for extreme motion applied to motion‐M0 data did not improve consistency with reference data in cases where motion corrupted >15% of DW images. In contrast, DTI parameters calculated with motion‐M2 data were consistent with reference data. Conclusion: This proof‐of‐principle study demonstrates that motion compensating diffusion gradients can mitigate artifacts because of continuous motion in DTI of the brain and offers promise for improved DTI accessibility. Further study will be necessary to determine the robustness of the approach in patient populations with high susceptibility to head motion. [ABSTRACT FROM AUTHOR] more...

Purpose: To integrate 3D CEST EPI with an unevenly segmented RF irradiation module and preliminarily demonstrate it in the clinical setting. Methods: A CEST MRI with unevenly segmented RF saturation was implemented, including a long primary RF saturation to induce the steady‐state CEST effect, maintained with repetitive short secondary RF irradiation between readouts. This configuration reduces relaxation‐induced blur artifacts during acquisition, allowing fast 3D spatial coverage. Numerical simulations were performed to select parameters such as flip angle (FA), short RF saturation duration (Ts2), and the number of readout segments. The sequence was validated experimentally with data from a phantom, healthy volunteers, and a brain tumor patient. Results: Based on the numerical simulation and l‐carnosine gel phantom experiment, FA, Ts2, and the number of segments were set to 20°, 0.3 s, and the range from 4 to 8, respectively. The proposed method minimized signal modulation in the human brain images in the kz direction during the acquisition and provided the blur artifacts‐free CEST contrast over the whole volume. Additionally, the CEST contrast in the tumor tissue region is higher than in the contralateral normal tissue region. Conclusions: It is feasible to implement a highly accelerated 3D EPI CEST imaging with unevenly segmented RF irradiation. [ABSTRACT FROM AUTHOR] more...

Purpose: To improve the image reconstruction for prospective motion correction (PMC) of simultaneous multislice (SMS) EPI of the brain, an update of receiver phase and resampling of coil sensitivities are proposed and evaluated. Methods: A camera‐based system was used to track head motion (3 translations and 3 rotations) and dynamically update the scan position and orientation. We derived the change in receiver phase associated with a shifted field of view (FOV) and applied it in real‐time to each k‐space line of the EPI readout trains. Second, for the SMS reconstruction, we adapted resampled coil sensitivity profiles reflecting the movement of slices. Single‐shot gradient‐echo SMS‐EPI scans were performed in phantoms and human subjects for validation. Results: Brain SMS‐EPI scans in the presence of motion with PMC and no phase correction for scan plane shift showed noticeable artifacts. These artifacts were visually and quantitatively attenuated when corrections were enabled. Correcting misaligned coil sensitivity maps improved the temporal SNR (tSNR) of time series by 24% (p = 0.0007) for scans with large movements (up to ˜35 mm and 30°). Correcting the receiver phase improved the tSNR of a scan with minimal head movement by 50% from 50 to 75 for a United Kingdom biobank protocol. Conclusion: Reconstruction‐induced motion artifacts in single‐shot SMS‐EPI scans acquired with PMC can be removed by dynamically adjusting the receiver phase of each line across EPI readout trains and updating coil sensitivity profiles during reconstruction. The method may be a valuable tool for SMS‐EPI scans in the presence of subject motion. [ABSTRACT FROM AUTHOR] more...

Amine‐weighted chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) is particularly valuable as an amine‐ and pH‐sensitive imaging technique in brain tumors, targeting the intrinsically high concentration of amino acids with exchangeable amine protons and reduced extracellular pH in brain tumors. Amine‐weighted CEST MRI contrast is dependent on the glioma genotype, likely related to differences in degree of malignancy and metabolic behavior. Amine‐weighted CEST MRI may provide complementary value to anatomic imaging in conventional and exploratory therapies in brain tumors, including chemoradiation, antiangiogenic therapies, and immunotherapies. Continual improvement and clinical testing of amine‐weighted CEST MRI has the potential to greatly impact patients with brain tumors by understanding vulnerabilities in the tumor microenvironment that may be therapeutically exploited. [ABSTRACT FROM AUTHOR] more...

Amide proton transfer‐weighted (APTw) MR imaging shows promise as a biomarker of brain tumor status. Currently used APTw MRI pulse sequences and protocols vary substantially among different institutes, and there are no agreed‐on standards in the imaging community. Therefore, the results acquired from different research centers are difficult to compare, which hampers uniform clinical application and interpretation. This paper reviews current clinical APTw imaging approaches and provides a rationale for optimized APTw brain tumor imaging at 3 T, including specific recommendations for pulse sequences, acquisition protocols, and data processing methods. We expect that these consensus recommendations will become the first broadly accepted guidelines for APTw imaging of brain tumors on 3 T MRI systems from different vendors. This will allow more medical centers to use the same or comparable APTw MRI techniques for the detection, characterization, and monitoring of brain tumors, enabling multi‐center trials in larger patient cohorts and, ultimately, routine clinical use. [ABSTRACT FROM AUTHOR] more...

Structural hippocampal abnormalities are common in many neurological and psychiatric disorders, and variation in hippocampal measures is related to cognitive performance and other complex phenotypes such as stress sensitivity. Hippocampal subregions are increasingly studied, as automated algorithms have become available for mapping and volume quantification. In the context of the Enhancing Neuro Imaging Genetics through Meta Analysis Consortium, several Disease Working Groups are using the FreeSurfer software to analyze hippocampal subregion (subfield) volumes in patients with neurological and psychiatric conditions along with data from matched controls. In this overview, we explain the algorithm's principles, summarize measurement reliability studies, and demonstrate two additional aspects (subfield autocorrelation and volume/reliability correlation) with illustrative data. We then explain the rationale for a standardized hippocampal subfield segmentation quality control (QC) procedure for improved pipeline harmonization. To guide researchers to make optimal use of the algorithm, we discuss how global size and age effects can be modeled, how QC steps can be incorporated and how subfields may be aggregated into composite volumes. This discussion is based on a synopsis of 162 published neuroimaging studies (01/2013–12/2019) that applied the FreeSurfer hippocampal subfield segmentation in a broad range of domains including cognition and healthy aging, brain development and neurodegeneration, affective disorders, psychosis, stress regulation, neurotoxicity, epilepsy, inflammatory disease, childhood adversity and posttraumatic stress disorder, and candidate and whole genome (epi‐)genetics. Finally, we highlight points where FreeSurfer‐based hippocampal subfield studies may be optimized. [ABSTRACT FROM AUTHOR] more...

Purpose: Functional magnetic resonance imaging (fMRI) during infancy poses challenges due to practical, methodological, and analytical considerations. The aim of this study was to implement a hardware‐related approach to increase subject compliance for fMRI involving awake infants. To accomplish this, we designed, constructed, and evaluated an adaptive 32‐channel array coil. Methods: To allow imaging with a close‐fitting head array coil for infants aged 1‐18 months, an adjustable head coil concept was developed. The coil setup facilitates a half‐seated scanning position to improve the infant's overall scan compliance. Earmuff compartments are integrated directly into the coil housing to enable the usage of sound protection without losing a snug fit of the coil around the infant's head. The constructed array coil was evaluated from phantom data using bench‐level metrics, signal‐to‐noise ratio (SNR) performances, and accelerated imaging capabilities for both in‐plane and simultaneous multislice (SMS) reconstruction methodologies. Furthermore, preliminary fMRI data were acquired to evaluate the in vivo coil performance. Results: Phantom data showed a 2.7‐fold SNR increase on average when compared with a commercially available 32‐channel head coil. At the center and periphery regions of the infant head phantom, the SNR gains were measured to be 1.25‐fold and 3‐fold, respectively. The infant coil further showed favorable encoding capabilities for undersampled k‐space reconstruction methods and SMS techniques. Conclusions: An infant‐friendly head coil array was developed to improve sensitivity, spatial resolution, accelerated encoding, motion insensitivity, and subject tolerance in pediatric MRI. The adaptive 32‐channel array coil is well‐suited for fMRI acquisitions in awake infants. [ABSTRACT FROM AUTHOR] more...

Purpose: To develop an image‐based motion‐robust diffusion MRI (dMRI) acquisition framework that is able to minimize motion artifacts caused by rigid and nonrigid motion, applicable to both brain and tongue dMRI. Methods: We developed a novel prospective motion‐correction technique in dMRI using a phase image–based real‐time motion‐detection method (PITA‐MDD) with re‐acquisition of motion‐corrupted images. The prospective PITA‐MDD acquisition technique was tested in the brains and tongues of volunteers. The subjects were instructed to move their heads or swallow, to induce motion. Motion‐detection efficacy was validated against visual inspection as the gold standard. The effect of the PITA‐MDD technique on diffusion‐parameter estimates was evaluated by comparing reconstructed fiber tracts using tractography with and without re‐acquisition. Results: The prospective PITA‐MDD technique was able to effectively and accurately detect motion‐corrupted data as compared with visual inspection. Tractography results demonstrated that PITA‐MDD motion detection followed by re‐acquisition helps in recovering lost and misshaped fiber tracts in the brain and tongue that would otherwise be corrupted by motion and yield erroneous estimates of the diffusion tensor. Conclusion: A prospective PITA‐MDD technique was developed for dMRI acquisition, providing improved dMRI image quality and motion‐robust diffusion estimation of the brain and tongue. [ABSTRACT FROM AUTHOR] more...

Purpose: To develop an ultrafast 3D gradient echo–based MRI method with constant TE and high tolerance to B0 inhomogeneity, dubbed ERASE (equal‐TE rapid acquisition with sequential excitation), and to introduce its use in BOLD functional MRI (fMRI). Theory and Methods: Essential features of ERASE, including spin behavior, were characterized, and a comparison study was conducted with conventional EPI. To demonstrate high tolerance to B0 inhomogeneity, in vivo imaging of the mouse brain with a fiber‐optic implant was performed at 9.4 T, and human brain imaging (including the orbitofrontal cortex) was performed at 3 T and 7 T. To evaluate the performance of ERASE in BOLD‐fMRI, the characteristics of SNR and temporal SNR were analyzed for in vivo rat brains at 9.4 T in comparison with multislice gradient‐echo EPI. Percent signal changes and t‐scores are also presented. Results: For both mouse brain and human brain imaging, ERASE exhibited a high tolerance to magnetic susceptibility artifacts, showing much lower distortion and signal dropout, especially in the regions involving large magnetic susceptibility effects. For BOLD‐fMRI, ERASE provided higher temporal SNR and t‐scores than EPI, but exhibited similar percent signal changes in in vivo rat brains at 9.4 T. Conclusion: When compared with conventional EPI, ERASE is much less sensitive, not only to EPI‐related artifacts such as Nyquist ghosting, but also to B0 inhomogeneity including magnetic susceptibility effects. It is promising for use in BOLD‐fMRI, providing higher temporal SNR and t‐scores with constant TE when compared with EPI, although further optimization is needed for human fMRI. [ABSTRACT FROM AUTHOR] more...

Purpose: Subject motion in MRI remains an unsolved problem; motion during image acquisition may cause blurring and artifacts that severely degrade image quality. In this work, we approach motion correction as an image‐to‐image translation problem, which refers to the approach of training a deep neural network to predict an image in 1 domain from an image in another domain. Specifically, the purpose of this work was to develop and train a conditional generative adversarial network to predict artifact‐free brain images from motion‐corrupted data. Methods: An open source MRI data set comprising T2*‐weighted, FLASH magnitude, and phase brain images for 53 patients was used to generate complex image data for motion simulation. To simulate rigid motion, rotations and translations were applied to the image data based on randomly generated motion profiles. A conditional generative adversarial network, comprising a generator and discriminator networks, was trained using the motion‐corrupted and corresponding ground truth (original) images as training pairs. Results: The images predicted by the conditional generative adversarial network have improved image quality compared to the motion‐corrupted images. The mean absolute error between the motion‐corrupted and ground‐truth images of the test set was 16.4% of the image mean value, whereas the mean absolute error between the conditional generative adversarial network‐predicted and ground‐truth images was 10.8% The network output also demonstrated improved peak SNR and structural similarity index for all test‐set images. Conclusion: The images predicted by the conditional generative adversarial network have quantitatively and qualitatively improved image quality compared to the motion‐corrupted images. [ABSTRACT FROM AUTHOR] more...

Objectives: Unilateral spatial neglect (USN) is the incapacity to respond to stimuli presented opposite to a dysfunctional cerebral hemisphere. It is usually caused by non‐dominant hemisphere lesions, leads to poorer prognosis and might be underdiagnosed. The objectives of the study were to ascertain the presence of USN in acute stroke patients and analyze the possible degree of underdiagnosis in a Stroke Unit. Materials and Methods: Prospective study of consecutive non‐dominant hemisphere stroke patients within a period of 21 months. "Line Bisection" and "Triangles Cancellation" tests were used for USN screening and "Circle Gap Detection Task" to confirm the USN. The results were compared with routine Stroke Unit assessment using the NIHSS to determine the possible degree of underdiagnosis. Results: A total of 62 subjects, 38 women (61.29%), mean age of 74.05 (SD 10.5) years, were included. USN was diagnosed in 25 cases (40.3%) but 56% of them were not detected in routine evaluation using the NIHSS. Conclusions: Unilateral spatial neglect, a common cognitive deficit after acute stroke, is greatly underdiagnosed in routine Stroke Unit assessment. The use of simple USN‐specific screening tools would improve diagnosis and therefore the possibility of implementing appropriate rehabilitation strategies. [ABSTRACT FROM AUTHOR] more...

Neuroimaging and neuropsychological studies have identified the involvement of the right posterior region in the processing of visual words. Interestingly, in contrast, ERP studies of the N170 typically demonstrate selectivity for words more strikingly over the left hemisphere. Why is right hemisphere selectivity for words during the N170 epoch typically not observed, despite the clear involvement of this region in word processing? One possibility is that amplitude differences measured on averaged ERPs in previous studies may have been obscured by variation in peak latency across trials. This study examined this possibility by using single-trial analysis. Results show that words evoked greater single-trial N170s than control stimuli in the right hemisphere. Additionally, we observed larger trial-to-trial variability on N170 peak latency for words as compared to control stimuli over the right hemisphere. Results demonstrate that, in contrast to much of the prior literature, the N170 can be selective to words over the right hemisphere. This discrepancy is explained in terms of variability in trial-to-trial peak latency for responses to words over the right hemisphere. [ABSTRACT FROM AUTHOR] more...

Analysis of the structural connectomes can lead to powerful insights about the brain's organization and damage. However, the accuracy and reproducibility of constructing the structural connectome done with different acquisition and reconstruction techniques is not well defined. In this work, we evaluated the reproducibility of the structural connectome techniques by performing test-retest (same day) and longitudinal studies (after 1 month) as well as analyzing graph-based measures on the data acquired from 22 healthy volunteers (6 subjects were used for the longitudinal study). We compared connectivity matrices and tract reconstructions obtained with the most typical acquisition schemes used in clinical application: diffusion tensor imaging (DTI), high angular resolution diffusion imaging (HARDI), and diffusion spectrum imaging (DSI). We observed that all techniques showed high reproducibility in the test-retest analysis (correlation >.9). However, HARDI was the only technique with low variability (2%) in the longitudinal assessment (1-month interval). The intraclass coefficient analysis showed the highest reproducibility for the DTI connectome, however, with more sparse connections than HARDI and DSI. Qualitative (neuroanatomical) assessment of selected tracts confirmed the quantitative results showing that HARDI managed to detect most of the analyzed fiber groups and fanning fibers. In conclusion, we found that HARDI acquisition showed the most balanced trade-off between high reproducibility of the connectome, higher rate of path detection and of fanning fibers, and intermediate acquisition times (10-15 minutes), although at the cost of higher appearance of aberrant fibers. [ABSTRACT FROM AUTHOR] more...

ABSTRACT BACKGROUND AND PURPOSE To develop a qualitative brain magnetic resonance imaging (MRI) scoring system for comatose cardiac arrest patients that can be used in clinical practice. METHODS Consecutive comatose postcardiac arrest patients were prospectively enrolled. Routine MR brain sequences were scored by two independent blinded experts. Predefined brain regions were qualitatively scored on the fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging (DWI) sequences according to the severity of the abnormality on a scale from 0 to 4. The mean score of the raters was used. Poor outcome was defined as death or vegetative state at 6 months. RESULTS Sixty-eight patients with 88 brain MRI scans were included. Median time from the arrest to the initial MRI was 77 hours (IQR 58-144 hours). At 100% specificity, the 'cortex score' performed best in predicting unfavorable outcome with a sensitivity of 55%-60% (95% CI 41-74) depending on time window selection. When comparing the 'cortex score' with historically used predictors for poor outcome, MRI improved the sensitivity for poor outcome over conventional predictors by 27% at 100% specificity. CONCLUSIONS A qualitative MRI scoring system helps assess hypoxic-ischemic brain injury severity following cardiac arrest and may provide useful prognostic information in comatose cardiac arrest patients. [ABSTRACT FROM AUTHOR] more...

Cerebral amyloid angiopathy ( CAA) is of increasing clinical and research interest as the ability to detect it and its consequences by neuroimaging in living subjects has advanced. There is also increasing interest in understanding its possible role in the development of intracerebral hemorrhage, Alzheimer's disease ( AD) and vascular dementia. In this article, the literature on this subject is reviewed and novel findings relating CAA to subcortical white matter damage in 224 subjects in the Oxford project to Investigate Memory and Ageing ( OPTIMA) are reported. The relationship between CAA and subcortical tissue damage in the OPTIMA subjects was found to be critically dependent on ApoE genotype, there being a positive relationship between measures of CAA and subcortical small vessel disease in ApoE ε4 carriers and a significant negative relationship in ApoE ε2 carriers. These findings draw attention, as have many other studies, to the importance of ApoE genotype as a major risk factor not only for dementia but also for damage to blood vessels in the aging brain. [ABSTRACT FROM AUTHOR] more...

Background and purpose Recently, brain and vascular imaging have been added to clinical variables to identify patients with transient ischaemic attack ( TIA) with a high risk of stroke recurrence. The aim of our study was to externally validate the ABCD3-I score and the same score taking into account intracranial circulation. Methods We analyzed data from 1137 patients with TIA from the PROMAPA study who underwent diffusion-weighted magnetic resonance imaging ( DWI) within 7 days of symptom onset. Clinical variables and diagnostic work-up were recorded prospectively. The end-points were subsequent stroke at 7 and 90 days follow-up. Results A total of 463 (40.7%) subjects fulfilled all inclusion criteria. During follow-up, eight patients (1.7%) had a stroke within 7 days, and 14 (3.1%) had a stroke within 3 months. In the Cox proportional hazard multivariate analyses, the combination of large-artery atherosclerosis and positive DWI remained as independent predictors of stroke recurrence at 7- and 90-day follow-up [ HR 8.23, 95% confidence interval ( CI) 2.89-23.46, P < 0.001]. The ABCD3-I score was a powerful predictor of subsequent stroke. The area under the receiver operating characteristic curve was 0.83 (95% CI 0.72-0.93) at 7 days and 0.69 (95% CI 0.53-0.85) at 90 days. When we include intracranial vessel disease in the score, the area under the curve increases but the difference observed was non-significant. Conclusion The inclusion of vascular and neuroimaging information to clinical scales ( ABCD3-I score) provides important prognostic information and also helps management decisions, although it cannot give a complete distinction between high-risk and low-risk groups. [ABSTRACT FROM AUTHOR] more...

A 64-channel brain array coil was developed and compared to a 32-channel array constructed with the same coil former geometry to precisely isolate the benefit of the 2-fold increase in array coil elements. The constructed coils were developed for a standard clinical 3T MRI scanner and used a contoured head-shaped curved former around the occipital pole and tapered in at the neck to both improve sensitivity and patient comfort. Additionally, the design is a compact, split-former design intended for robust daily use. Signal-to-noise ratio and noise amplification ( G-factor) for parallel imaging were quantitatively evaluated in human imaging and compared to a size and shape-matched 32-channel array coil. For unaccelerated imaging, the 64-channel array provided similar signal-to-noise ratio in the brain center to the 32-channel array and 1.3-fold more signal-to-noise ratio in the brain cortex. Reduced noise amplification during highly parallel imaging of the 64-channel array provided the ability to accelerate at approximately one unit higher at a given noise amplification compared to the sized-matched 32-channel array. For example, with a 4-fold acceleration rate, the central brain and cortical signal-to-noise ratio of the 64-channel array was 1.2- and 1.4-fold higher, respectively, compared to the 32-channel array. The characteristics of the coil are demonstrated in accelerated brain imaging. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR] more...

ABSTRACT BACKGROUND AND PURPOSE High- b-value diffusion-weighted imaging (DWI) ( b= 2,000 and b= 3,000 second/mm2) offers theoretical advantages over DWI examinations at b= 1,000 second/mm2 for detection of acute ischemic stroke. The purpose of this study was to determine whether high- b-value DWI are better than b= 1,000 images in TIA patients. METHODS We compared DWI obtained with 3 different b-values (1,000, 2,000, and 3,000 second/mm2) and fluid-attenuated inversion recovery (FLAIR) sequences in 75 consecutive TIA patients. DWI examinations were performed within 3.25 ± 1.5 days after the onset of symptoms. Presence of ischemic lesion, volume, lesion conspicuity, and lesion distinction were determined. RESULTS A total of 40 (53.3%) patients revealed ischemic acute lesions with b= 1,000 while 34 (45.3%) were positive on FLAIR. High- b-value DWI did not increase the sensitivity for the detection of acute brain ischemia. The median lesion value increased as the b-value did: .17 mL (interquartile range [IQR] .12-.78) at b= 1,000; .19 mL (IQR .13-1.00) at b= 2,000; .29 mL (IQR .14-1.02) at b= 3,000; and .12 mL (IQR .04-.62 mL) on FLAIR ( P < .001). As b-value increased, we observed hyperintensities in white matter that could erroneously be considered as acute ischemia. CONCLUSION High- b-value DWI did not improve the conspicuity and distinction of the ischemic lesions. [ABSTRACT FROM AUTHOR] more...

Diffusion-weighted magnetic resonance imaging (DWI) is a sensitive diagnostic tool for detecting acute ischaemic lesions in patients with transient ischaemic attacks (TIAs). The additional predictive value of DWI lesion patterns is not well known. Two hundred and fifty-four consecutive patients with TIA underwent DWI within 7 days of symptom onset. The presence and pattern of acute ischaemic lesions were related to clinical features, etiology, and stroke recurrence at seven- and 90-day follow-up. Diffusion-weighted images abnormalities were identified in 117 (46.1%) patients. The distribution of DWI lesions was cortical, 31; subcortical, 32; scattered lesions in one arterial territory (SPOT) 42; and in multiple areas, 12. SPOT were significantly associated with motor weakness, large-artery atherosclerosis (LAA), and the cardioembolic subtype of TIA. Single cortical lesions were also associated with cardioembolism, whereas subcortical acute lesions were associated with recurrent episodes, dysarthria, and motor weakness. During follow-up, seven patients had a stroke within 7 days (2.8%, 95% CI 2.9-6.4%), and 12 had a stroke within 3 months (4.7%%, 95% CI 2.9-6.4%). In the Cox logistic regression model, the combination of LAA and positive DWI remained as independent predictors of stroke recurrence at 90-day follow-up (HR 5.78, 95 CI 1.74-19.21, P = 0.004). According to our results, MRI, including DWI, should be considered a preferred diagnostic test when investigating patients with potential TIAs. The combination of neuroimaging and vascular information could improve prognostic accuracy in patients with TIA. [ABSTRACT FROM AUTHOR] more...

The article discusses a proposed method for simulating brain perfusion. The proposed method is aimed at generating test data to compare quantitative brain perfusion methods without bias. It simulates contrast agent solute and blood flow through cerebral vasculature with disease-specific configurations. It models blood and contrast agent dynamics as a combination of convection and diffusion in tubular networks. more...

Neuroimaging is essential in the work-up of patients with intractable epilepsy. In pediatric patients with medically refractory epilepsy, cortical dysplasias account for a large percentage of the epileptogenic substrate. Unfortunately, these are also the most subtle lesions to identify. For this reason, there has been ongoing interest in utilizing new advanced magnetic resonance imaging (MRI) techniques to improve the ability to identify, diagnose, characterize, and delineate cortical dysplasias. Technologic gains such as multichannel coils (32 phased array and beyond) and higher field strengths (3T, 7T, and greater) coupled with newer imaging sequences such as arterial spin labeling (ASL), susceptibility weighted imaging (SWI) and diffusion tensor/spectrum imaging (DTI/DSI) are likely to increase yield. Improved MRI techniques coupled with a multimodality approach including magnetoencephalography (MEG), positron emission tomography (PET), and other techniques will increase sensitivity and specificity for identifying cortical dysplasias. [ABSTRACT FROM AUTHOR] more...