Tesla MR Scanner Research Articles

Нейровізуалізаційні особливості нервової системи в дітей раннього віку з епілептичними енцефалопатіями за даними МР-трактографії

The aim is to analyze neuroimaging changes in the nervous system of children of an early and preschool age with epileptic encephalopathies (EE) according to MR-tractography to improve the diagnosis of these conditions. Materials and methods. 157 children aged 0 to 6 years with EE, epileptiform and developmental encephalopathies (DEE) were examined. The study included MR-tractography using a 3 Tesla MR scanner. Fractional anisotropy (FA) and average diffusion coefficient (ADC) were determined in Broca's and Wernicke's areas, left arcuate tract, both uncinate tracts, corpus callosum and thalamus. The examined children were divided into 3 groups: I - 75 children with EE, with the onset of seizures before 1 year of age; II - 44 children with EE, with the onset of seizures at the age of 1-3 years; III - 38 children with DEE. Differences between groups were assessed using the Kruskal-Wallis test and Pearson's Chi-square (χ²) test. Results. In children with EE from groups I and II, there was a significant decrease in FA and an increase in ADC in the areas of both language centers and the right uncinate tract in comparison with children of group III (p<0.05). In the group I with EE, there was a significant decrease in FA in the left uncinate tract, knee and trunk of the MT in comparison with the groups II and III of children (p<0.05). It was found that more than 60% of children from group I had destruction of the fibers of the arcuate tract and in the area of one of the speech centers, and 70% had hypoplasia and destruction of the left uncinate tract. In the children of group II with EE, hypoplasia of the anterior (63.6%) and posterior (65.9%) parts of the arcuate tract and the right uncinate tract (81.8%) was detected. Among children from group III, more than 60% had an abnormal location of Broca's speech center, and more than 70 % had an abnormal location of Wernicke's center, almost 80 % had an abnormal location of the left uncinate tract. Conclusions. It was found that in children with EE and DEE, according to MR tractography, there is a decrease in FA indicators and an increase in ADC in all studied structures (arcuate and uncinate tract, corpus callosum, thalamus) in comparison with the reference values given in the scientific literature. The detected changes indicate a violation of the structural integrity of the white matter in Broca's and Wernicke's centers and associative pathways, which will lead to the optimization of early diagnosis and prognosis of consequences in children with EE and DEE. The study was carried out in accordance with the principles of the Declaration of Helsinki. The study protocol was approved by the Local Ethics Committees of the institutions indicated in the work. The informed consent of the children's parents was obtained for conducting the research. No conflict of interest was declared by the authors.

Functional MRI of the Brainstem for Assessing Its Autonomic Functions: From Imaging Parameters and Analysis to Functional Atlas.

The brainstem is a crucial component of the central autonomic nervous (CAN) system. Functional MRI (fMRI) of the brainstem remains challenging due to a range of factors, including diverse imaging protocols, analysis, and interpretation. To develop an fMRI protocol for establishing a functional atlas in the brainstem. Prospective cross-sectional study. Ten healthy subjects (four males, six females). Using a 3.0 Tesla MR scanner, we acquired T1-weighted images and three different fMRI scans using fMRI protocols of the optimized functional Imaging of Brainstem (FIBS), the Human Connectome Project (HCP), and the Adolescent Brain Cognitive Development (ABCD) project. The temporal signal-to-noise-ratio (TSNR) of fMRI data was compared between the FIBS, HCP, and ABCD protocols. Additionally, the main normalization algorithms (i.e., FSL-FNIRT, SPM-DARTEL, and ANTS-SyN) were compared to identify the best approach to normalize brainstem data using root-mean-square (RMS) error computed based on manually defined reference points. Finally, a functional autonomic brainstem atlas that maps brainstem regions involved in the CAN system was defined using meta-analysis and data-driven approaches. ANOVA was used to compare the performance of different imaging and preprocessing pipelines with multiple comparison corrections (P ≤ 0.05). Dice coefficient estimated ROI overlap, with 50% overlap between ROIs identified in each approach considered significant. The optimized FIBS protocol showed significantly higher brainstem TSNR than the HCP and ABCD protocols (P ≤ 0.05). Furthermore, FSL-FNIRT RMS error (2.1 ± 1.22 mm; P ≤ 0.001) exceeded SPM (1.5 ± 0.75 mm; P ≤ 0.01) and ANTs (1.1 ± 0.54 mm). Finally, a set of 12 final brainstem ROIs with dice coefficient ≥0.50, as a step toward the development of a functional brainstem atlas. The FIBS protocol yielded more robust brainstem CAN results and outperformed both the HCP and ABCD protocols. 2 TECHNICAL EFFICACY: Stage 1.

High-resolution Magnetic Resonance Imaging visualizes intracranial large artery involvement in Giant Cell Arteritis.

Giant Cell arteritis (GCA) is a large vessel vasculitis, typically involving the aorta and its branches with predilection for the scalp arteries. Intracranial involvement is still part of ongoing research. We assess inflammation of the intracranial arteries on 3D-black-blood magnetic resonance imaging (3D-CS-BB-MRI) in patients with GCA and age-matched controls. 105 patients with 3D-CS-BB-MRI of the brain were included in this retrospective dual-center case-control study; 55 with diagnosed GCA and 50 age-matched controls. High-resolution 3D-CS-BB-MRI was performed on a 3 Tesla MR scanner with a post-contrast 3D-compressed-sensing (CS) MR pulse sequence, specifically a T1-weighted sampling perfection, application-optimized contrasts using different flip angle evolution (SPACE) pulse sequence with whole-brain coverage and isotropic resolution of 0.55 mm3. Two neuroradiologists blinded to clinical data independently scored the cerebral arteries qualitatively for inflammation; circumferential vessel wall thickening and contrast enhancement were scored positive for vasculitis. 8 of 55 GCA patients (14.5%) showed inflammation of at least one intracranial artery. The internal carotid artery (ICA) was affected in 6/55 (10.9%), the vertebral artery in 4/55 (7.3%) and the basilar artery and posterior cerebral artery in 1/55 (1.8%). All patients with inflammatory changes reported headaches and none showed any focal neurological deficit. Besides headache and general weakness, there was no significant correlation between inflammation of the intracranial arteries and clinical symptoms. No age-matched control patient showed inflammatory changes of the intracranial arteries. High-resolution 3D-CS-BB-MRI revealed inflammatory changes of intracranial arteries in 14.5% of GCA patients with the intradural ICA as the most frequently affected vessel.

Magnetic Resonance Imaging Spectrum of Cauda Equina and Conus Lymphoma: Keys to Unravel the Differential Diagnosis with a Review of the Literature

Central nervous system lymphoma is not an uncommon condition, but spinal lymphoma with isolated involvement of the conus medullaris and cauda equina is a rare entity. Our study aims to evaluate the various magnetic resonance imaging (MRI) features of cauda equina and conus lymphoma. This retrospective study was carried out on nine patients with histopathologically proven cauda equina and conus lymphoma, who were presented at a tertiary care hospital between January 2018 and June 2020. All patients underwent lumbar spine MRI scans using a 1.5 Tesla MR scanner. The clinical data and different MRI findings were analyzed with an independent sample t-test and paired-samples t-test. Among the nine patients with cauda equina and conus lymphoma, three had primary lymphoma and six had secondary lymphoma. Six patients (66.7%) showed a diffuse pattern of involvement of cauda equina and conus medullaris, while three patients (33.3%) showed a focal pattern. T2-weighted imaging (T2WI) hypo to isointense signal intensity lesions were observed in six patients (66.7%) and T2WI iso to slight hyperintensities in three patients (33.3%). Diffuse sheet-like thickening and postcontrast enhancement of the thickened cauda equina nerve roots were observed in two patients of primary and one patient with secondary lymphoma. The diagnosis of cauda equina and conus lymphoma especially primary lymphoma is challenging and requires a high index of clinical suspicion as distinguishing this entity from similar conditions is difficult solely on MRI. Early diagnosis of this entity is important for early institution of treatment for increasing the chances of survival and improvement of symptoms.

Comparison of diagnostic accuracy of magnetic resonance spectroscopy with conventional magnetic resonance imaging for brain tumors and correlation with histopathology as gold standard

Background; Despite a large number of revolutionized advancements in Imaging technology clinicians are unable to get hundred percent accurate results. Multiple limitations have been observed in Imaging modalities. Multiple published trials are available online on the evaluations of these imaging modalities individually and in combinations to find out the level of accuracy of these technologies. Objective; This study was design to compare the diagnostic accuracy of MR Spectroscopy with MRI which is a conventional diagnostic tool for brain tumor diagnosis while keeping the Histopathology evaluation as Gold Standard. Methodology; The patients who fulfilled the inclusion criteria were included in study. All scans were carried out on GE 1.5 Tesla MR Scanner using head coil. Axial T1W, T2W, Fluid Attenuated Inversion Recovery (FLAIR), Sagittal T2W, Coronal Fluid Attenuation. Inversion Recovery (FLAIR) and T1W post- contrast Axial, Coronal and Sagittal images were acquired. MR spectroscopy was performed through single voxel technique. Final diagnosis was made on histopathology results. The reports of biopsy were co related with radiological diagnosis of MRI and MRS. Results; The study was conducted with 150 suspected cases. There were 85(56.7%) males and 65(43.3%) females. Histopathology 100(66.7%) cases were confirmed positive and 50(33.3%) negative.

Placental volume in pregnant women with opioid use: prenatal MRI assessment

Objective Opioid use in pregnant women is a growing public health concern and is shown to be associated with lower infant birth weights. Placental volume changes in prior studies correlated with various maternal and fetal conditions. We aimed to identify differences between placental volumes in pregnant women with opioid use, and control pregnant women without drug use. Methods We prospectively recruited 27 healthy pregnant women and 17 pregnant women with opioid use disorder who were on medication-assisted treatment (MAT). All women underwent placenta/fetal MRI at 27–39 weeks gestation on a 3 Tesla MR scanner. Placental volumes were measured in a blinded fashion using a previously validated technique. Multiple linear regression was used to identify associations of placental volume with multiple maternal and fetal clinical factors. The significance threshold was set at p < .05. Results Placental volume was significantly associated with gestational age at MRI (p < .0001), fetal sex (p = .027), MAT with smoking (p = .0008), MAT with polysubstance use (p = .01), and maternal BMI (p = .032). Placental volume was not associated with opioid MAT alone in our cohort. Conclusion For pregnant women on medication-assisted treatment for opioid use disorder, there was no significant difference in placental volume compared to healthy pregnant women. However, concomitant smoking and polysubstance use in the setting of medication-assisted treatment may be detrimental to placental health. To our knowledge, this is the first study assessing placental volume in opioid use on prenatal MRI. These results support the benefit of medication-assisted treatment during pregnancy; however additional studies are needed to further elucidate the impact of opioid use on placental and fetal development and postnatal outcomes.

Global hippocampus functional connectivity as a predictive neural marker for conversion to future mood disorder in unaffected offspring of bipolar disorder parents.

Hippocampus-related functional alteration in genetically at-risk individuals may reflect an endophenotype of a mood disorder. Herein, we performed a prospective study to investigate whether baseline hippocampus functional connectivity (FC) in offspring of patients with bipolar disorder (BD) would predict subsequent conversion to mood disorder. Eighty bipolar offspring and 40 matched normal controls (NC) underwent resting state functional MRI (rsfMRI) scanning on a 3.0 Tesla MR scanner. The offspring were subdivided into asymptomatic offspring (AO) (n=41) and symptomatic offspring (SO) (n=39) according to whether they manifested subthreshold mood symptoms. After identifying the different hippocampus FCs between the AO and SO, a logistic regression analysis was conducted to investigate whether the baseline hippocampus FCs predicted a future mood disorder during a 6-year follow-up. We identified seven baseline para/hippocampus FCs that showed differences between AO and SO, which were entered as predictive features in the logistic regressive model. Of the 80 bipolar offspring entering the analysis, the FCs between left hippocampus and left precuneus, and between right hippocampus and left posterior cingulate, showed a discriminative capacity for predicting future mood disorder (area-under-curve, or AUC=75.76 % and 75.00 % respectively), and for predicting BD onset (AUC=77.46 % and 81.63 %, respectively). The present findings revealed high predictive utility of the hippocampus resting state FCs for future mood disorder and BD onset in individuals at familial risk. These neural markers can potentially improve early detection of individuals carrying particularly high risk for future mood disorder.

Segmentation and differentiation of periventricular and deep white matter hyperintensities in 2D T2-FLAIR MRI based on a cascade U-net.

White matter hyperintensities (WMHs) are a subtype of cerebral small vessel disease and can be divided into periventricular WMHs (pvWMHs) and deep WMHs (dWMHs). pvWMHs and dWMHs were proved to be determined by different etiologies. This study aimed to develop a 2D Cascade U-net (Cascade U) for the segmentation and differentiation of pvWMHs and dWMHs on 2D T2-FLAIR images. A total of 253 subjects were recruited in the present study. All subjects underwent 2D T2-FLAIR scan on a 3.0 Tesla MR scanner. Both contours of pvWMHs and dWMHs were manually delineated by the observers and considered as the gold standard. Fazekas scale was used to evaluate the burdens of pvWMHs and dWMHs, respectively. Cascade U consisted of a segmentation U-net and a differentiation U-net and was trained with a combined loss function. The performance of Cascade U was compared with two other U-net models (Pipeline U and Separate U). Dice similarity coefficient (DSC), Matthews correlation coefficient (MCC), precision, and recall were used to evaluate the performances of all models. The linear correlations between WMHs volume (WMHV) measured by all models and the gold standard were also conducted. Compared with other models, Cascade U exhibited a better performance on WMHs segmentation and pvWMHs identification. Cascade U achieved DSC values of 0.605 ± 0.135, 0.517 ± 0.263, and 0.510 ± 0.241 and MCC values of 0.617 ± 0.122, 0.526 ± 0.263, and 0.522 ± 0.243 on the segmentation of total WMHs, pvWMHs, and dWMHs, respectively. Cascade U exhibited strong correlations with the gold standard on measuring WMHV (R2 = 0.954, p < 0.001), pvWMHV (R2 = 0.933, p < 0.001), and dWMHV (R2 = 0.918, p < 0.001). A significant correlation was found on lesion volume between Cascade U and gold standard (r > 0.510, p < 0.001). Cascade U showed competitive results in segmentation and differentiation of pvWMHs and dWMHs on 2D T2-FLAIR images, indicating potential feasibility in precisely evaluating the burdens of WMHs.

Magnetic resonance imaging as a non-invasive tool to assess gastric emptying in mice.

Methods to study gastric emptying in rodents are time consuming or terminal, preventing repetitive assessment in the same animal. Magnetic resonance imaging (MRI) is a non-invasive technique increasingly used to investigate gastrointestinal function devoid of these shortcomings. Here, we evaluated MRI to measure gastric emptying in control animals and in two different models of gastroparesis. Mice were scanned using a 9.4 Tesla MR scanner. Gastric volume was measured by delineating the stomach lumen area. Control mice were scanned every 30 min after ingestion of a 0.2 g meal and stomach volume was quantified. The ability of MRI to detect delayed gastric emptying was evaluated in models of morphine-induced gastroparesis and streptozotocin-induced diabetes. Magnetic resonance imaging reproducibly detected increased gastric volume following ingestion of a standard meal and progressively decreased with a half emptying time of 59 ± 5 min. Morphine significantly increased gastric volume measured at t= 120 min (saline: 20 ± 2 vs morphine: 34 ± 5 mm3 ; n= 8-10; p< 0.001) and increased half emptying time using the breath test (saline: 85 ± 22 vs morphine: 161 ± 46 min; n= 10; p< 0.001). In diabetic mice, gastric volume assessed by MRI at t= 60 min (control: 23 ± 2 mm3 ; n= 14 vs diabetic: 26 ± 5 mm3 ; n= 18; p= 0.014) but not at t= 120 min (control: 21 ± 3 mm3 ; n= 13 vs diabetic: 18 ± 5 mm3 ; n= 18; p= 0.115) was significantly increased compared to nondiabetic mice. Our data indicate that MRI is a reliable and reproducible tool to assess gastric emptying in mice and represents a useful technique to study gastroparesis in disease models or for evaluation of pharmacological compounds.

Assessment of brain and hippocampal volume in patients with Cushing's disease.

The purpose of this study was to assess the volumes of the hippocampus, grey matter, and the whole brain in patients with active Cushing's disease compared to a control group. We included 36 patients diagnosed with Cushing's disease, with pituitary magnetic resonance imaging (MRI) performed as a standard preoperative assessment. The sample size of the control group was 26 persons. MRI studies were acquired with a 3.0 Tesla MR scanner equipped with a 24-channel head coil. The MRI study protocol included a pre-contrast 3D T1-weighted gradient sequence. Volumetric segmentation of the brain structures was performed using version 6.0 of the FreeSurfer software. We observed statistically significant reduction in the grey matter volume in the study group as compared to the control group (p < 0.001), with no significant differences in the volume of the whole brain (p = 0.104), left hippocampus (p = 0.790), and right hippocampus (p = 0.517). There was a strong positive correlation between grey matter volume and brain volume (r = 0.75, p < 0.001), independent of the study group. The study showed unevenly distributed brain atrophy in patients suffering from Cushing's disease, with no significant hippocampal atrophy. Significant atrophy was observed within the grey matter, potentially constituting a preliminary stage of whole-brain atrophy.

Dual gradient echo in-phase and out of phase sequences in assessment of hepatic iron overload in patients with beta-thalassemia, would be better?

PurposeTo evaluate the diagnostic accuracy of the dual gradient-echo (GRE) in- and out-of-phase sequences as a quantitative tool for hepatic iron overload in comparison with MRI R2* relaxometry in paediatric patients with beta-thalassemia. MethodSixty-three patients with beta-thalassemia major (transfusion-dependent) or beta-thalassemia intermedia (transfusion- and non-transfusion-dependent) were referred from the paediatric department (haematology unit) to the radiology department at a university hospital. The paediatrician conducted a clinical examination for the studied group, assessed their laboratory data, conducted R2* relaxometry and dual gradient echo sequences to calculate R2* and relative signal intensity index at the axial mid-section of the liver, and studied their correlation. A 1.5 Tesla MR scanner was used (Achieva; Philips Medical Systems, the Netherlands). Data were fed to the computer and analysed using the IBM SPSS software package version 20.0 (Armonk, NY: IBM Corp). The Kolmogorov-Smirnov test was used to verify the normality of distribution. The significance of the results was determined at the 5% level. The Chi-square, Fisher’s exact correction, Pearson coefficient, and Bland–Altman tests were used. ResultsDual gradient-echo in- and out-of-phase sequences using visual assessment accurately assessed 93.65% of our patient group with hepatic iron overload. A significant correlation was found between the relative signal intensity index and hepatic MRI R2* relaxometry (p < 0.001, r = 0.861). ConclusionsDual gradient-echo in and out-of-phase sequences are good imaging tools for hepatic iron detection and quantification. These sequences showed good correlation with R2* relaxometry (r = 0.861, p < 0.001).

Influence of Immunosuppressive Regimen on Diffusivity and Oxygenation of Kidney Transplants-Analysis of Functional MRI Data from the Randomized ZEUS Trial.

The ZEUS study was a multi-center randomized controlled trial investigating the effect of early conversion from a ciclosporin-based to an everolimus-based regimen on graft function twelve months post-transplantation. In this investigator-initiated sub-study, functional magnetic resonance imaging (fMRI) of kidney grafts was prospectively performed to non-invasively assess differences in graft oxygenation, diffusion and perfusion between groups and time-points using diffusion-weighted imaging (DWI) and blood oxygen level-dependent (BOLD)-MRI. Sixteen patients underwent DWI and BOLD-MRI at months 4.5 and 12 post-transplantation on a 3 Tesla and 1.5 Tesla (n = 3) MR scanner. After exclusion due to image quality, outlier values or missing data, DWI was analyzed for ten subjects; BOLD for eight subjects. The diffusion coefficient ADCD decreased in the CsA-treated group over time, whereas it increased in the EVE group (p = 0.046, medulla). The change in ADCD from months 4.5 to 12 significantly differed between groups in the cortex (p = 0.033) and medulla (p = 0.019). In BOLD, cortico-medullary transverse relaxation rate R2* increased (decreased tissue oxygen) in the CsA-treated and decreased in EVE-treated groups over time. Similarly, R2* values at month 12 were higher in the CsA-treated group compared to the EVE-treated group. There was no significant difference for the perfusion fraction FP. In conclusion, this prospective sub-study of the ZEUS trial suggests an impact of immunosuppressive regimen on fMRI parameters of the kidney graft.

Multiparametric Magnetic Resonance Imaging in Evaluation of Benign and Malignant Breast Masses with Pathological Correlation

BackgroundDynamic contrast-enhanced (DCE) MRI sequences plays a vital role in diagnosing breast masses with high sensitivity and specificity as compared to other diagnostic modalities. The addition of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values significantly improves diagnostic accuracy. This study aimed to study the breast masses on DCE-MRI, restricted diffusion on DWI, ADC values, and choline peak on spectroscopy in breast cancer diagnosis.Material and methodsThis study was a prospective observational study which involved subjects with breast lumps. Baseline data was collected from the patients along with pertinent clinical history and relevant laboratory investigations. MR mammography (MRM) was performed on a 1.5 Tesla MR Scanner (MAGNETOM® Avanto, Siemens AG, Munich Germany) using a dedicated double breast coil.ResultsForty-one subjects were included with a total of 54 breast masses in them. The mean age of the study population was 47.1±14.7 years. From the MRI final diagnosis, the majority (53.70%) were diagnosed as malignant lesions and 46.30% as benign. Out of 20 lesions diagnosed as benign on histopathology, only five percent had ADC value <1.3 ×10−3mm2/s, and the majority (95%) had ADC value >1.3 ×10−3mm2/s. All 20 lesions were circumscribed, ovoid, or round in shape showing no restricted diffusion on DWI, with corresponding ADC value of >1.3×10−3mm2/s, homogeneous post-contrast enhancement, or with dark internal septations, type I kinetic enhancement curve, and they showed no choline peak on spectroscopy. Out of 34 malignant lesions diagnosed on histopathology, the majority (85.29%) displayed restricted diffusion on DWI and had an ADC value of <1.3×10−3mm2/s, most of them had spiculated margins, type II/ III kinetic curve with choline peak on spectroscopy.ConclusionMultiparametric MR mammography, which included DCE-MRM, DWI, ADC values, and spectroscopy, correlated well with the histopathological diagnosis of benign and malignant breast masses.

Neurofilaments light: Possible biomarker of brain modifications in bipolar disorder

IntroductionBrain white matter (WM) abnormalities are biomarkers that seem to be involved in bipolar disorder (BD) aetiology and maintenance. Evidences suggest a possible association between neurodegeneration, neuroaxonal alterations and BD. A biomarker that is recently drawing attention is neurofilaments light (NfL) chain, a cytoskeletal intermediate filament protein expressed in neurons. To investigate neuroimaging alterations associated with BD, we studied the association between NfL levels and WM microstructure. MethodsNfL plasma quantification was performed in a sample of 45 depressed BD patients compared with 29 healthy controls (HC) using Quanterix SIMOA assay. Statistical analysis were conducted to evaluate NfL levels differences between BD patients and controls. Analyses of the diffusion data were performed using Tract Based Spatial Statistics (TBSS) on Diffusion Tensor images acquired using a 3.0 Tesla MR scanner. ResultsPatients had higher NfL levels than HC (9.13 ± 4.78 vs 4.28 ± 2.39 pg/ml; p < 0.001). The separate-slopes analysis of variance showed a significant interaction of age with diagnosis (Likelihood-ratio test: χ2 = 27.52, p < 0.0001) with significant effects only in the BD sample (p = 0.023). The TBSS analysis, performed within the BD sample, showed a significant positive correlation between NfL levels and axial diffusivity (AD) in a wide single cluster encompassing several tracts. DiscussionOur results suggest that the physiological age-dependent increment of NfL level is augmented in BD, possibly because of increased remodelling and plasticity processes related to an accelerated ageing condition. The positive association between NfL levels and AD, may reflect a condition of remyelination and axonal regeneration.

Microscopic multifrequency MR elastography for mapping viscoelasticity in zebrafish.

The zebrafish (Danio rerio) has become an important animal model in a wide range of biomedical research disciplines. Growing awareness of the role of biomechanical properties in tumor progression and neuronal development has led to an increasing interest in the noninvasive mapping of the viscoelastic properties of zebrafish by elastography methods applicable to bulky and nontranslucent tissues. Microscopic multifrequency MR elastography is introduced for mapping shear wave speed (SWS) and loss angle (φ) as markers of stiffness and viscosity of muscle, brain, and neuroblastoma tumors in postmortem zebrafish with 60µm in-plane resolution. Experiments were performed in a 7 Tesla MR scanner at 1, 1.2, and 1.4kHz driving frequencies. Detailed zebrafish viscoelasticity maps revealed that the midbrain region (SWS = 3.1±0.7m/s, φ=1.2±0.3radian [rad]) was stiffer and less viscous than telencephalon (SWS = 2.6±0. 5 m/s, φ=1.4±0.2rad) and optic tectum (SWS = 2.6±0.5m/s, φ=1.3±0.4rad), whereas the cerebellum (SWS = 2.9±0.6m/s, φ=0.9±0.4rad) was stiffer but less viscous than both (all p<.05). Overall, brain tissue (SWS = 2.9±0.4m/s, φ=1.2±0.2rad) had similar stiffness but lower viscosity values than muscle tissue (SWS = 2.9±0.5m/s, φ=1.4±0.2rad), whereas neuroblastoma (SWS = 2.4±0.3m/s, φ=0.7±0.1rad, all p<.05) was the softest and least viscous tissue. Microscopic multifrequency MR elastography-generated maps of zebrafish show many details of viscoelasticity and resolve tissue regions, of great interest in neuromechanical and oncological research and for which our study provides first reference values.

RELATIONSHIP OF D-DIMERS WITH THE DURATION OF CEREBRAL VENOUS SINUS THROMBOSIS (CVST): A DESCRIPTIVE STUDY IN TERTIARY HEALTH CARE HOSPITAL OF DISTRICT PESHAWAR PAKISTAN.

Purpose CVST is a serious condition with a recent incidence of 13 million persons per year. (1) It has a highly variable presentation and may manifest itself with no recognizable risk factor, Magnetic resonance venography (MRV) is the investigation of choice for its diagnosis. However, since MRV is not readily available and is costly, this study tried to find the relationship between the levels of D-dimers as marker and duration of CVST. D-dimers are degraded fibrin products which are found to be raised in pulmonary embolism and deep venous thrombosis.&#x0D; Methods: Total 49 patients (male to female ratio 1:6) mean age 36.37 13years) with MRV proven CVST were included in the study. This descriptive cross-sectional study was conducted from January 2015-April 2017, on 49 confirmed patients of CVST, in Lady Reading Hospital. In patients suspected of CVST, magnetic resonance imaging of the brain with MRV was performed without delay on a 1.5 tesla MR scanner using T1, T2, flair, and diffusion weighted imaging sequences with a two-dimensional time of flight MRV. D-dimers were estimated by a rapid latex agglutination slide test technique using monoclonal antibodies. Data was analyzed using SPSS version 19. Frequencies, mean were calculated for quantitative data while Chi-square test was used for qualitative data. Sensitivity and specificity were calculated.&#x0D; Result: The duration of symptoms was 3-60 days (mean 22 days). The mean value of D-dimers levels recorded in micrograms were recorded as 1456&#x0D; Conclusion: D-dimers levels were high in acute and subacute stage of CVST. However, there were cases in our study who despite having acute and subacute stage of CVST had normal D-dimers levels for unknown reasons.

Prediction of H3K27M mutation status of diffuse midline gliomas using MRI features.

Presurgical prediction of H3K27M mutation in diffuse midline gliomas (DMGs) on MRI is desirable. The purpose of this study is to elaborate conventional MRI (cMRI) features of H3K27M-mutant DMGs and identify features that could discriminate them from wild-type (WT) DMGs. CMRI features of 123 patients with DMG were evaluated conforming to the institutional research protocols. Multimodality MRI was performed on 1.5 or 3.0 Tesla MR Scanners with imaging protocol, including T1-weighted (w), T2w, fluid-attenuated inversion recovery, diffusion-weighted, susceptibility-weighted, and postcontrast T1w sequences. Pertinent cMRI features were annotated along the lines of Visually AcceSAble Rembrandt Images features, and Intra Tumoral Susceptibility Signal score (ITSS) was evaluated. R software was used for statistical analysis. Sixty-one DMGs were H3K27M-mutant (mutant DMGs). The patients in the H3K27M-mutant DMG group were younger compared to the WT-DMG group (mean age 24.13 ± 13.13 years vs. 35.79±18.74 years) (p = 0.016). The two groups differed on five cMRI features--(1) enhancement quality (p = 0.032), (2) thickness of enhancing margin (p = 0.05), (3) proportion of edema (p = 0.002), (4) definition of noncontrast-enhancing tumor (NCET) margin (p = 0.001), and (5) cortical invasion (p = 0.037). The mutant DMGs showed greater enhancement and greater thickness of enhancing margin, while the WT DMGs exhibited significantly larger edema proportion with poorly defined NCET margins and cortical invasion. ITSS was not significantly different among the groups. CMRI features like enhancement quality, the thickness of the enhancing margin, proportion of edema, definition of NCET margin, and cortical invasion can discriminate between the H3K27M-mutant and WT DMGs.

Safety of MRI in the localization of implanted intracranial electrodes for refractory epilepsy.

This is an observational study to evaluate the safety of magnetic resonance imaging (MRI) to localize subdural grids and depth electrodes in patients with refractory epilepsy using a 1.5 Tesla MR scanner. We implemented an optimized MRI protocol providing adequate image quality for the assessment of subdural grids and depth electrodes, while minimizing the specific absorption rate (SAR). We reviewed all MRI studies performed in patients with subdural grids and depth electrodes between January 2010 and October 2018. Image quality was graded as acceptable or nonacceptable for the assessment of intracranial device positioning. We reviewed the medical record and any imaging obtained after intracranial implant removal for adverse event or complication occurring during and after the procedure. Ninety-nine patients with refractory epilepsy underwent MRI scans using a magnetization-prepared rapid acquisition of gradient echo sequence and a transmit-receive head coil with depth electrodes and subdural grids in place. Two patients underwent two separate depth electrode implantations for a total of 101 procedures and MRI scans. No clinical adverse events were reported during or immediately after imaging. Image quality was graded as acceptable for 97 MRI scans. Review of follow-up CT and MRI studies after implant removal, available for 70 patients, did not demonstrate unexpected complications in 69 patients. In our experience, a low SAR MRI protocol can be used to safely localize intracranial subdural grids and depth electrode in patients with refractory epilepsy.

CHARACTERIZATION OF HIPPOCAMPUS ON EPILEPTIC PATIENTS ON MRI USING TEXTURE ANALYSIS TECHNIQUES

The aim of this study was to characterize the hippocampus in Sudanese epileptic patients in MR images using image texture analysis techniques in order to differentiate hippocampus between the normal and epileptic patient. There were two groups of the patients were examined by using Signal-GE 1.5Tesla MR Scanner which was used with patients with known epilepsy and normal T1 weighted brain. MRI finding patients, 101 and 105 patients respectively examined in period from December 2017- March 2018, where the variables of the study were MRI images entered to the IDL program as input for further analysis, using window 3*3 the images texture was extracted from hippocampus (head, body and tail) that include, mean, STD, variance, energy, and entropy then the comparison was made to differentiate between the normal and abnormal hippocampus. The extracted feature classified using linear discriminate analysis. The classification score function is used to classify the hippocampus classes was as flows:&#x0D; Epileptic= (.271×mean) + (.026×variance) + (7.475× Part) -32.134&#x0D; Normal= (.240×mean) + (.052×variance) + (2.960× Part) -13.684&#x0D; The study confirmed that it’s possible to differentiate between normal and epileptic hippocampus body, head, and tail in sagittal section texturally. The result showed that the classification result is best in the tail where higher classification accuracy will be achieved followed by body and then head.

Iron Content in Deep Gray Matter as a Function of Age Using Quantitative Susceptibility Mapping: A Multicenter Study.

PurposeTo evaluate the effect of resolution on iron content using quantitative susceptibility mapping (QSM); to verify the consistency of QSM across field strengths and manufacturers in evaluating the iron content of deep gray matter (DGM) of the human brain using subjects from multiple sites; and to establish a susceptibility baseline as a function of age for each DGM structure using both a global and regional iron analysis.MethodsData from 623 healthy adults, ranging from 20 to 90 years old, were collected across 3 sites using gradient echo imaging on one 1.5 Tesla and two 3.0 Tesla MR scanners. Eight subcortical gray matter nuclei were semi-automatically segmented using a full-width half maximum threshold-based analysis of the QSM data. Mean susceptibility, volume and total iron content with age correlations were evaluated for each measured structure for both the whole-region and RII (high iron content regions) analysis. For the purpose of studying the effect of resolution on QSM, a digitized model of the brain was applied.ResultsThe mean susceptibilities of the caudate nucleus (CN), globus pallidus (GP) and putamen (PUT) were not significantly affected by changing the slice thickness from 0.5 to 3 mm. But for small structures, the susceptibility was reduced by 10% for 2 mm thick slices. For global analysis, the mean susceptibility correlated positively with age for the CN, PUT, red nucleus (RN), substantia nigra (SN), and dentate nucleus (DN). There was a negative correlation with age in the thalamus (THA). The volumes of most nuclei were negatively correlated with age. Apart from the GP, THA, and pulvinar thalamus (PT), all the other structures showed an increasing total iron content despite the reductions in volume with age. For the RII regional high iron content analysis, mean susceptibility in most of the structures was moderately to strongly correlated with age. Similar to the global analysis, apart from the GP, THA, and PT, all structures showed an increasing total iron content.ConclusionA reasonable estimate for age-related iron behavior can be obtained from a large cross site, cross manufacturer set of data when high enough resolutions are used. These estimates can be used for correcting for age related iron changes when studying diseases like Parkinson’s disease, Alzheimer’s disease, and other iron related neurodegenerative diseases.