Fluid-attenuated Inversion Recovery Magnetic Resonance Imaging Research Articles

Technical note: Quantitative optimization of the FLAIR sequence in post mortem magnetic resonance imaging

The fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) sequence aims at suppressing the signal of the cerebrospinal fluid (CSF) by acquiring images at the time point at which the longitudinal magnetization and therefore the signal of CSF is zero. This time point is also called the null point inversion time (TInull). However, the FLAIR sequence is impaired by the temperature dependency of TInull in post mortem MRI due to the lower body temperature of the deceased subject. Therefore, the temperature correction of TInull is crucial for correctly suppressing the CSF signal in post mortem FLAIR imaging. Thus, the goal of this study was to determine the temperature effect on post mortem TInull for achieving a robust suppression of the CSF signal in in situ post mortem MRI using the FLAIR sequence. For this purpose, nine deceased subjects underwent an in situ MRI brain examination on a 3 T MRI scanner. TInull of CSF was determined quantitatively based on different FLAIR acquisitions using varying inversion times. The brain and rectal temperatures were determined prior to the MRI scan. A significant positive linear relation was found between TInull of CSF and the brain temperature, as well as between TInull of CSF and the rectal temperature. The found linear relations between TInull and both brain and rectal temperatures allow correcting TInull for varying temperatures of the deceased. This in turn enables an optimal suppression of the CSF signal in future post mortem FLAIR MRI acquisitions.

Paramagnetic rims are a promising diagnostic imaging biomarker in multiple sclerosis

Background: White matter lesions (WMLs) on brain magnetic resonance imaging (MRI) in multiple sclerosis (MS) may contribute to misdiagnosis. In chronic active lesions, peripheral iron-laden macrophages appear as paramagnetic rim lesions (PRLs). Objective: To evaluate the sensitivity and specificity of PRLs in differentiating MS from mimics using clinical 3T MRI scanners. Method: This retrospective international study reviewed MRI scans of patients with MS (n = 254), MS mimics (n = 91) and older healthy controls (n = 217). WMLs, detected using fluid-attenuated inversion recovery MRI, were analysed with phase-sensitive imaging. Sensitivity and specificity were assessed for PRLs. Results: At least one PRL was found in 22.9% of MS and 26.1% of clinically isolated syndrome (CIS) patients. Only one PRL was found elsewhere. The identification of ⩾1 PRL was the optimal cut-off and had high specificity (99.7%, confidence interval (CI) = 98.20%–99.99%) when distinguishing MS and CIS from mimics and healthy controls, but lower sensitivity (24.0%, CI = 18.9%–36.6%). All patients with a PRL showing a central vein sign (CVS) in the same lesion (n = 54) had MS or CIS, giving a specificity of 100% (CI = 98.8%–100.0%) but equally low sensitivity (21.3%, CI = 16.4%–26.81%) Conclusion: PRLs may reduce diagnostic uncertainty in MS by being a highly specific imaging diagnostic biomarker, especially when used in conjunction with the CVS.

White Matter Lesion Segmentation for Multiple Sclerosis Patients implementing deep learning.

The aim of this work is to address the problem of White Matter Lesion (WML) segmentation employing Magnetic Resonance Imaging (MRI) images from Multiple Sclerosis (MS) patients through the application of deep learning. A U-net based architecture containing a contrastive path and an expanding path prior to the final pixel-wise classification is implemented. The data are provided by the Ippokratio Radiology Center of Ioannina and include Fluid-Attenuated Inversion Recovery (FLAIR) MRI images from 30 patients in three phases, baseline and two follow ups. The prediction results are quite significant in terms of pixel-wise classification. The implemented deep learning model demonstrates Dice coefficient 0.7292, Precision 75.92% and Recall 70.16% in 2D slices of FLAIR MRI non-skull stripped images.

Segmentation and volume quantification of MR Images for the detection and monitoring multiple sclerosis progression.

Multiple Sclerosis (MS) lesions detection and disease's progression monitoring at the same time, play an important role. The purpose of this research is to demonstrate a method for detecting MS plaques and volume estimation from MR Images for monitoring the progression of the disease and the brain atrophy caused. In the proposed research, a clustering-based method is utilized in order to delineate MS plaques in brain, based on anatomical information, brain geometry and lesion features. In addition to volumetric information concerning lesions and whole brain volume, volume quantification is employed to estimate MS atrophy by measuring Brain Parenchymal Fraction (BPF). In the present study, Fluid Attenuated Inversion Recovery (FLAIR) images were utilized for the detection of MS lesions and BPF evaluation, while Tl-weighted MR Images utilized in volume estimation. 30 MS patients were included in a dataset consisted of 3D FLAIR and T1-weighted MR images in order to evaluate the proposed technique. MRI scans performed in two different clinical visits, a baseline and a visit after 6 months. The results extracted in segmentation of MS lesions in terms of sensitivity is 73.80 %. The BPF at baseline estimated to 0.82 ± 0.01, and at 1stfollow up, 0.83 ± 0.01. Finally, the brain volume loss between baseline and after 6 months is 0.4%.

Genesis of Antibiotic Resistance (AR) LXXXV: Turbulence Modeling(TM) of Hemodynamics in Simplified Severe Sepsis Protocol‐2 (SSSP‐2)‐NCT01663701: Clinical Connotation of Monitoring ISP [BP(PP), MAP, CBF, ICP, CPPopt, Comatose GCS 3, and CCP] for Attenuation of IHM

Based on the theoretical inferences derived from industrial CFD modules: Flow‐3DÒ Hydro FD simulation Model 04; 05_sediment_transport FLOW‐3D HydroÒ, (Courtesy: Flow‐3D HydroÒ), The Beauty of Vortex Streets, May 5, 2021; Curve Fitting of Solution Data in COMSOL Multiphysics®, July 27, 2021 © 2021 BY COMSOL INC., https://earthobservatory.nasa.gov/images/90734/two‐views‐of‐von‐karman‐vortices (NASA). and hemodynamic data (SSSP‐2), here we present a plausible physiological basis for the benefit of monitoring ISP for attenuation 100% ihm in the usual care cohort of SSSP‐2 (PMID: 28973227). Hypothesis & Rationale:Monitoring the ISP‐induced transient APG, eases the point of care clinical intervention for the recovery from GCS3 to homeostasis. Geometry: RBC, WBC, platelets, p47; Whole blood viscosity ~ 3 centipoise (cP) or ~0.003 Pascal second (Pa. s) p53; Blood velocity in the Human Blood Vessels: table 2.1 p63, Blood Vol. Distribution: Table 2.2, p64; Stress–Strain Curve, Fig 2.15 p 78; ISBN:9780128024089. Gov Eq: Segmental Cerebral Perfusion Pressure Equation for The Intracranial Compartment: SPP = Pd − ICP = FFR · CPP − Ge · (1 − FFR) · (ICP − Pe) (PMCID: PMC8032738; PMID: 33833266). Derivation & Prospects:ISP has been shown to induce cerebral hypoperfusion in turn vasogenic edema altering contralateral/ipsilateral CBF due to increased blood flow through the anterior communicating artery (Acom). Case Report (PMCID: PMC7332508; PMID: 32637214): A 72‐year‐old male presented with the right‐sided hemiparesis and underwent MRI. MR imaging show an acute infarction of the left frontal lobe [Figure 1] and bilateral internal carotid artery (ICA) stenosis (NASCET: Rt: 90%, peak systolic velocity 425 cm/s and Lt: NASCET 70%, peak systolic velocity 212 cm/s). After 2 months, SPECT showed an decrease in CBF in the right cerebral hemisphere [Figure 2a]. INVOS‐4100 cerebral oximeter based determination of the effect of carotid clamping and shunting on oxygen saturation (rSO2) showed rSO2 readings were lower than ipsilateral rSO2 readings. SPECT showed a decrease in CBF around the infarction [Figure 2b]. SPECT indicated a contralateral increase in CBF [Figure 2b]. Tx, with free‐radical scavenger(Rx), showed an improvement in CBF, and laterality disappeared 2 weeks after CEA [Figure 2c and d]. The CBF of both sides equaled 2 weeks later [Figure 3]. Subsequent MR imaging with fluid‐attenuated inversion recovery (FLAIR) images showed a local high‐intensity lesion around a previous infarction in comparison with before CEA [Figure 4a and b]. FLAIR MR imaging 2 weeks after initial surgery confirmed the complete disappearance of the high‐intensity lesion [Figure 4c]. Taken together, the focal vasogenic edema induced neurologic impairment is shown to be alleviated by treating edema and cerebral ischemia while monitoring hemodynamic parameters. This model could be applied for the attenuation of fluid bolus augmented VKVS, collapsing of cerebral vessels leading to 100% ihm, in the usual care group in SSSP‐2 (PMID: 28973227).

Anti-LGI1 encephalitis recurring 3\xa0years after the first episode: a case report

BackgroundPatients with antibodies against leucine-rich glioma-inactivated 1 (LGI1) present with limbic encephalitis, which is clinically characterized by a subacute disturbance of memory and behavior, often experience seizures. Most patients have a monophasic course, often with hyponatremia.Case presentationHerein, we report a 67-year-old Japanese male presenting with involuntary neck movement, abnormal behavior and apraxia. He was disoriented to time and place and occasionally unable to follow directions. Laboratory tests revealed the patient had hyponatremia (131 mEq/L). Cerebrospinal fluid (CSF) analysis showed that the cell count (1/μL) and protein content (33 mg/dL) were in the normal ranges. Electroencephalography showed transient theta bursts in the right frontal lobe. Magnetic resonance imaging (MRI) of the brain demonstrated hyperintensities in the medial temporal lobe and basal forebrain on fluid-attenuated inversion recovery (FLAIR) without gadolinium enhancement. Anti-voltage-gated potassium channel (Anti-VGKC) complex antibodies were below the reference level for limbic encephalitis. Although the diagnosis was unknown, intravenous methylprednisolone therapy was effective. Three years later, the patient began to speak incoherently and became disoriented to time. FLAIR MRI of the brain revealed recurrence in the left medial temporal lobe. The patient’s serum sodium level was 131 mEq/L. After intravenous methylprednisolone therapy, he regained alertness. A CSF sample stored at the time of the first attack was assayed and the patient was found to be LGI1-positive and CASPR-2-negative, and the diagnosis of anti-LGI1 encephalitis was made.ConclusionsMonitoring serum sodium levels and the preserved samples from the first episode were useful for diagnosis.

Delve into Multiple Sclerosis (MS) lesion exploration: A modified attention U-Net for MS lesion segmentation in Brain MRI

Multiple Sclerosis (MS) is a Central Nervous System (CNS) disease that Magnetic Resonance Imaging (MRI) system can detect and segment its lesions. Artificial Neural Networks (ANNs) recently reached a noticeable performance in finding MS lesions from MRI. U-Net and Attention U-Net are two of the most successful ANNs in the field of MS lesion segmentation. In this work, we proposed a framework to segment MS lesions in Fluid-Attenuated Inversion Recovery (FLAIR) and T2 MRI images by modified U-Net and modified Attention U-Net. For this purpose, we developed some extra preprocessing on MRI scans, made modifications in the loss function of U-Net and Attention U-Net, and proposed using the union of FLAIR and T2 predictions to reach a better performance. Results show that the union of FLAIR and T2 predicted masks by the modified Attention U-Net reaches the performance of 82.30% in terms of Dice Similarity Coefficient (DSC) in the test dataset, which is a considerable improvement compared to the previous works.

Not Just Blood: Brain Fluid Systems and Their Relevance to Cerebrovascular Diseases.

Not Just Blood: Brain Fluid Systems and Their Relevance to Cerebrovascular Diseases.

342 Long-Term Follow-up of 54 Cases of Recurrent Glioblastoma Treated with Magnetic Resonance-Guided Laser Interstitial Thermal Therapy

INTRODUCTION: Magnetic resonance guided laser-induced thermal therapy (MRgLITT) is a novel minimally invasive procedural treatment for progressive cerebral lesions and cerebral edema related to post-radiation treatment effect. METHODS: We conducted a single-center retrospective study of pre-operative imaging, clinical characteristics and survival outcomes of 54 patients with previously treated (WHO Grade IV) between January 2013 to December 2020. RESULTS: The average age of patients was 58.7 ± 12.0 years. Patients underwent MRgLITT a median time of 21.6 ± 23.7 months from original diagnosis. 20% (n = 11) of patients had previous history of stereotactic radiosurgery, 61% (n = 33) intensity-modulated radiation therapy, and 80% (n = 43) chemotherapy. There was an average of 1.2 ± 0.7 prior surgical resections before MRgLITT was performed. 41% (n = 22) of patients were on dexamethasone at the time of treatment. The median pre-operative enhancing lesion volume on T1 gadolinium-enhanced magnetic resonance imaging (MRI) was 9.7 cm3 (standard error [SE], 2.0 cm3) and 27.0 cm3 (SE, 5.6 cm3) on T2 fluid-attenuated inversion recovery MRI. The pathology of the biopsies taken during MRgLITT confirmed tumor recurrence in 61% (n = 33) of patients, and treatment effect or reactive changes in 37% (n = 20) of patients. 67% (n = 28) experienced radiographic evidence of progression of the previously treated lesion, while 21% (n =9) and 12% (n = 5) experienced progression of a new lesion or both, respectively. Progression-free survival after MRgLITT was 3.5 months (standard error [SE], 0.6; 95% CI, 2.4-4.6). At the time of the study, 78% (n = 42) of patients were deceased. Mean overall survival time was 29.9 months (SE, 4.3; 95% CI, 21.4-38.3). Mean survival time after MRgLITT was 8.3 months (SE, 1.2; 95% CI, 5.9-10.6. Of the 12 remaining living patients, 36% (n = 4) had a decline in their clinical status at the time of last follow up, while 64% (n = 7) and 9% (n = 1) were stable or improved, respectively. Patients were followed for a mean time interval of 9.25 ± 12.2 months from MRgLITT. CONCLUSION: MRgLITT may be a viable, minimally invasive option for patients with glioblastoma but is associated with relatively short post-treatment progression-free survival.

A Convolutional Neural Network model for identifying Multiple Sclerosis on brain FLAIR MRI

Multiple Sclerosis (MS) is a neurodegenerative disease that occurs because of demyelination in nerve cells. Early treatment can be provided, and its progression can be prevented with an early diagnosis of the disease. The most remarkable finding in the identifying of MS disease is white matter lesions in the brain, which can be detected by magnetic resonance imaging (MRI). In this study, the identification of MS was performed with the proposed Convolutional Neural Network (CNN) model by detecting the presence of lesions from the brain Fluid-Attenuated Inversion Recovery (FLAIR) Magnetic Resonance (MR) images. The features of MS lesions in MR images are extracted with the proposed CNN model as an efficient and useful model with a low number of trainable parameters. The proposed CNN model has been compared with the traditional machine learning and state-of-the-art DL methods on a 5-fold cross-validation procedure. All methods are implemented on the same dataset. The results were obtained with both slice-level and patient-level data splitting methods. According to the results of slice-level splitting, the proposed CNN model achieved better success with the accuracy of 98.0% (± 0.02), the sensitivity of 97.9% (± 0.03), specificity of 98.3% (± 0.03), precision of 98.2% (± 0.03) values. In the results obtained with patient-level splitting, the accuracy of 90.3% (± 0.05), the sensitivity of 90.5% (± 0.05), the specificity of 90.1% (± 0.09), and the precision of 91.1% (± 0.09). The proposed CNN model obtained high and consistent performance in both splitting methods compared to other methods. © 2001 Elsevier Science. All rights reserved.

Delayed development of cerebral atrophy after cerebral hyperperfusion following arterial bypass for adult patients with ischemic moyamoya disease: supplementary analysis of a 5-year prospective cohort.

Adult patients with moyamoya disease (MMD) occasionally exhibit cerebral hyperperfusion after arterial bypass surgery, leading to persistent cognitive decline. The present supplementary analysis of a prospective 5-year cohort study aimed to determine whether cerebral hyperperfusion after arterial bypass surgery for adult patients with misery perfusion due to ischemic MMD causes cerebral atrophy, and whether the development of cerebral atrophy is related to persistent cognitive decline. In total, 31 patients who underwent arterial bypass surgery also underwent fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) and neuropsychological testing before surgery and at the end of a 5-year follow-up. The development of cerebral hyperperfusion and hyperperfusion syndrome after surgery was defined based on brain perfusion single-photon emission computed tomography (SPECT) findings and clinical symptoms. Univariate and multivariate logistic regression analyses of factors related to the development of cerebral atrophy on FLAIR MRI or cognitive decline on neuropsychological testing at the end of the 5-year follow-up were performed. Eleven patients (35%) developed cerebral atrophy in the frontal lobe where the superficial temporal artery was anastomosed. Cerebral hyperperfusion on brain perfusion SPECT (odds ratio [OR], 50.6; p = 0.0008) or cerebral hyperperfusion syndrome (OR, 41.8; p = 0.0026) was independently associated with the development of cerebral atrophy, and cerebral atrophy development was significantly associated with cognitive decline (OR, 47.7; p = 0.0010). Cerebral hyperperfusion after arterial bypass surgery for adult patients with misery perfusion due to ischemic MMD can cause cerebral atrophy related to persistent cognitive decline.

Use of multiparametric magnetic resonance imaging as a screening tool for the determination of acute ischemic stroke duration.

This study aimed to assess the usability of magnetic resonance imaging (MRI) parameters in the treatment of stroke patients whose symptom onset time is unknown. We evaluated MRI of the patients whose stroke symptoms began within 12-hours. For quantitative analysis, fluid-attenuated-inversion-recovery (FLAIR) and diffusion-weighted-imaging (DWI) signal-intensity-ratios (SIR) of the lesions were computed. For qualitative analysis, 'mismatch' between visibility of lesion on DWI-FLAIR was evaluated. Patients were analyzed according to the first 4.5/6 hours of stroke onset time. There was a moderate (r=0.569, p<0.001) correlation between symptom MRI time and FLAIR SIR and a weak correlation with DWI SIR (r=0.355, p=0.001). A FLAIR SIR threshold of ≤1.18 for predicted symptom onset 4.5 hours increased specificity (0.77 vs. 0.74) and sensitivity (0.77 vs. 0.69) as compared with visual analysis. A FLAIR SIR threshold of ≤1.19 for predicted symptom onset 6 hours increased sensitivity (0.76 vs. 0.67) and equal specificity (0.75 vs. 0.75) as compared with visual analysis. In hyperacute ischemic stroke, lesion age can be determined more accurately by the FLAIR SIR analysis than visual analysis. In patients whose stroke onset time is unknown, the FLAIR SIR can be used as a biomarker in the management of stroke patients.

MRI-Based Radiomics Signature for the Prediction of Response of Lung Cancer Brain Metastases After Whole-Brain Radio-Therapy

Local response prediction for brain metastases (BMs) from lung cancer after Whole-Brain Radiotherapy (WBRT) is challenging, as existing criteria are based solely on unidimensional measurements. This study sought to determine whether radiomic features of lung cancer BMs derived from pre-treatment magnetic resonance imaging (MRI) could be used to predict local response following WBRT.A total of 88 Lung Cancer patients with BMs treated with WBRT were analyzed. After volumes of interest were drawn, 944 radiomic features including first-order, shape, Gray Level Co-occurrence Matrix (GLCM), Gray Level Dependence Matrix (GLDM), Gray Level Run Length Matrix (GLRLM), Gray Level Size Zone Matrix (GLSZM), Neighborhood Gray Tone Difference Matrix (NGTDM), and Laplacian of Gaussian (LoG) features were extracted, using the baseline pre-treatment post-contrast T1 (T1c) and T2 fluid-attenuated inversion recovery (FLAIR) MRI sequences, respectively. Local response status was determined by contrasting the baseline and follow-up MRI according to the RANO-BM criteria. The independent samples t test or Mann-Whitney U test, and then least absolute shrinkage and selection operator (LASSO) were used for dimensionality reduction and feature selection. An adaboost classifier was trained using the selected radiomic features and evaluated using the area under the receiver operating characteristic curve (AUC) in both the training and testing sets. Other discrimination metrics, including classification accuracy, positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity, were also calculated.The optimal radiomics signature was developed based on a multivariable logistic regression with 4, 5, 6 radiomic features on T1c, T2 FLAIR and T1c+T2 FLAIR, respectively. The radiomics model based on T1c features presented the AUC of (0.920 vs. 0.805, respectively) for both the training and testing sets, followed by T2 FLAIR features (0.893 vs. 0.701, respectively), and T1c+T2 FLAIR features (0.971 vs. 0.857, respectively). The classification accuracy of the radiomics model also well predicted the local response of BMs for both the models), and training and testing sets (T1c: 82.9% vs. 77.8%, T2 FLAIR: 82.9% vs. 77.8%, T1c+T2 FLAIR: 90.0% vs. 77.8%, respectively).Radiomics holds promise for predicting local tumor response following WBRT in patients with lung cancer and brain metastases. A predictive model built on radiomic features from an institutional cohort performed well on cross-validation testing. These results warrant further validation in independent datasets. Such work could prove invaluable for guiding management of individual patients and assessing outcomes of novel interventions.

Technical note: A spiral fluid-attenuated inversion recovery magnetic resonance imaging technique for stereotactic radiosurgery treatment planning for trigeminal neuralgia.

Magnetic resonance imaging (MRI) is commonly used in treatment planning for stereotactic radiosurgery (SRS) of trigeminal neuralgia (TN). With current MRI techniques, the delineation of the trigeminal nerve root entry zone (REZ) may be degraded due to poor contrast and artifacts. The purpose of this work is to develop an MRI technique with better delineation of the trigeminal nerve REZ to improve SRS treatment planning for TN. A spiral fluid-attenuated inversion recovery (FLAIR) MRI technique was developed to improve image quality by improving tissue contrast, fluid suppression, artifact reduction, and signal-to-noise ratio (SNR). A concomitant-phase compensation method based on spiral gradient waveforms was implemented to minimize artifacts due to magnetic field change induced by the metal frame used in Gamma Knife treatment planning. The image quality of spiral FLAIR was assessed in four healthy volunteers. The geometric accuracy was quantitatively evaluated by registering spiral FLAIR to computed tomography (CT) images and comparing it with existing MRI techniques. The spiral FLAIR technique demonstrated better delineation of the trigeminal nerve REZ, improved tissue contrast of the brain stem, and minimized flow artifacts, compared to steady-state free precession (SSFP) MRI. Spiral FLAIR also improved fluid suppression, SNR, and artifacts, which contributed to better delineation of the trigeminal nerve REZ compared to conventional Cartesian FLAIR. The measured mean (± standard deviation) distance between spiral FLAIR and CT images is 0.98 ± 0.56mm, comparable to 0.40 ± 0.26mm in 3T T1 spoiled gradient echo (T1-SPGR), 0.59 ± 0.25mm in 3T SSFP, 0.66 ± 0.38mm in 1.5T T1-SPGR, and 0.61 ± 0.25mm in 1.5T Cartesian FLAIR. A spiral FLAIR technique with improved image quality and good geometric accuracy provides a potential alternative for treatment planning in SRS for TN patients.

A Crowdsourced Consensus on Supratotal Resection Versus Gross Total Resection for Anatomically Distinct Primary Glioblastoma.

Gross total resection (GTR) of contrast-enhancing tumor is associated with increased survival in primary glioblastoma. Recently, there has been increasing interest in performing supratotal resections (SpTRs) for glioblastoma. To address the published results, which have varied in part due to lack of consensus on the definition and appropriate use of SpTR. A crowdsourcing approach was used to survey 21 neurosurgical oncologists representing 14 health systems nationwide. Participants were presented with 11 definitions of SpTR and asked to rate the appropriateness of each definition. Participants reviewed T1-weighed postcontrast and fluid-attenuated inversion-recovery magnetic resonance imaging for 22 anatomically distinct glioblastomas. Participants were asked to assess the tumor location's eloquence, the perceived equipoise of enrolling patients in a randomized trial comparing gross total to SpTR, and their personal treatment plans. Most neurosurgeons surveyed (n=18, 85.7%) agree that GTR plus resection of some noncontrast enhancement is an appropriate definition for SpTR. Overall, moderate inter-rater agreement existed regarding eloquence, equipoise, and personal treatment plans. The 4 neurosurgeons who had performed >10 SpTRs for glioblastomas in the past year were more likely to recommend it as their treatment plan (P <.005). Cases were divided into 3 anatomically distinct groups based upon perceived eloquence. Anterior temporal and right frontal glioblastomas were considered the best randomization candidates. We established a consensus definition for SpTR of glioblastoma and identified anatomically distinct locations deemed most amenable to SpTR. These results may be used to plan prospective trials investigating the potential clinical utility of SpTR for glioblastoma.

Clinical usefulness of labyrinthine three-dimensional fluid-attenuated inversion recovery magnetic resonance images in idiopathic sudden sensorineural hearing loss.

Literature on the use of current magnetic resonance imaging (MRI) for patients with idiopathic sudden sensorineural hearing loss (ISSNHL) is reviewed, emphasizing the role of three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) MRI. The discussion focuses on the diagnostic role of temporal bone MRI using 3D-FLAIR and the relationship between MRI findings, clinical symptoms, and hearing outcome. The currently suggested MRI protocol for SSNHL includes a 3D T2-weighted steady-state free procession sequence or its equivalent, pre and postcontrast T1-weighted, and pre and postcontrast 3D-FLAIR sequences. The 3D-FLAIR image identifies an underlying labyrinthine condition in 24-57% of patients with ISSNHL, contributing to understanding the pathophysiologic mechanisms (e.g., labyrinthitis or labyrinthine hemorrhage). Recent studies demonstrated consistent results that initial hearing loss could be related to the signal change on the 3D-FLAIR image. Various results on 3D-FLAIR image value prediction for the final hearing outcome were shown. 3D-FLAIR MRI application identifies an underlying labyrinthine condition. Abnormal MRI findings correlate with initial hearing loss and accompanying symptoms and hearing outcome. Performing temporal bone MRI with 3D-FLAIR sequence may clarify probable ISSNHL pathophysiology, improve diagnostic accuracy, provide prognostic information to physicians, and possibly guide toward a more specific treatment.

White Matter Hyperintensity Burden and Collateral Circulation in Large Vessel Occlusion Stroke.

White matter hyperintensity (WMH), a marker of chronic cerebral small vessel disease, might impact the recruitment of leptomeningeal collaterals. We aimed to assess whether the WMH burden is associated with collateral circulation in patients treated by endovascular thrombectomy for anterior circulation acute ischemic stroke. Consecutive acute ischemic stroke due to anterior circulation large vessel occlusion and treated with endovascular thrombectomy from January 2015 to December 2017 were included. WMH volumes (periventricular, deep, and total) were assessed by a semiautomated volumetric analysis on fluid-attenuated inversion recovery-magnetic resonance imaging. Collateral status was graded on baseline catheter angiography using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology grading system (good when ≥3). We investigated associations of WMH burden with collateral status. A total of 302 patients were included (mean age, 69.1±19.4 years; women, 55.6%). Poor collaterals were observed in 49.3% of patients. Median total WMH volume was 3.76 cm3 (interquartile range, 1.09-11.81 cm3). The regression analyses showed no apparent relationship between WMH burden and the collateral status measured at baseline angiography (adjusted odds ratio, 0.987 [95% CI, 0.971-1.003]; P=0.12). WMH burden exhibits no overt association with collaterals in large vessel occlusive stroke.

Cortical involvement and leptomeningeal inflammation in myelin oligodendrocyte glycoprotein antibody disease: A three-dimensional fluid-attenuated inversion recovery MRI study

Background: Cortical demyelination and meningeal inflammation have been detected neuropathologically in multiple sclerosis (MS) and recently in myelin oligodendrocyte glycoprotein antibody disease (MOGAD). Objectives: To assess in vivo cortical and leptomeningeal involvement in MOGAD. Methods: We prospectively evaluated 11 MOGAD and 12 relapsing-remitting MS (RRMS) patients combining three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) and 3D-T1-weighted (3D-T1w) sequences at 3-Tesla magnetic resonance imaging (MRI). Leptomeningeal contrast enhancement (LMCE) was assessed on 3D-FLAIR post-gadolinium (3D-FLAIRGd). Cerebral cortical lesions (CCLs) were classified as either intracortical–subpial (IC–SP) or leukocortical (LC). Results: CCLs were present in 8/11 MOGAD and 12/12 RRMS patients, with the number of CCLs being significantly lower in MOGAD (median (interquartile range (IQR)) 3 (0.5–4) vs 12 (4.75–19), p = 0.0032). In MOGAD, IC–SP lesions were slightly more prevalent than LC lesions (2 (0–2.5) vs 1 (0–2), p = 0.6579); whereas in RRMS, IC–SP lesions were less prevalent than LC lesions (3.5 (2.75–5.5) vs 9 (2–12.75), p = 0.27). LMCE was observed in 3/11 MOGAD and 1/12 RRMS patients; MOGAD with LMCE showed an increased median number of CCLs compared with MOGAD without LMCE (8 (4–9) vs 2.5 (0.75–3.25), p = 0.34). No correlation was observed between MOGAD MRI findings and (a) MOGAD duration, (b) serum MOG-immunoglobulin G1 titers, and (c) oligoclonal band presence. Conclusion: We described cortical lesion topography and detected for the first time LMCE using 3D-FLAIRGd sequences in MOGAD patients.

Assessment of Magnetic Resonance Imaging Changes and Functional Outcomes Among Adults With Severe Herpes Simplex Encephalitis

Current guidelines recommend brain magnetic resonance imaging (MRI) for clinical management of patients with severe herpes simplex encephalitis (HSE). However, the prognostic value of brain imaging has not been demonstrated in this setting. To investigate the association between early brain MRI data and functional outcomes of patients with HSE at 90 days after intensive care unit (ICU) admission. This multicenter cohort study was conducted in 34 ICUs in France from 2007 to 2019 and recruited all patients who received a clinical diagnosis of encephalitis and exhibited cerebrospinal fluid positivity for herpes simplex virus DNA in the polymerase chain reaction analysis. Data analysis was performed from January to April 2020. All patients underwent a standard brain MRI during the first 30 days after ICU admission. MRI acquisitions were analyzed by radiologists blinded to patients' outcomes, using a predefined score. Multivariable logistic regression and supervised hierarchical classifiers methods were used to identify factors associated with poor outcome at 90 days, defined by a score of 3 to 6 (indicating moderate-to-severe disability or death) on the Modified Rankin Scale. Overall, 138 patients (median [interquartile range {IQR}] age, 62.6 [54.0-72.0] years; 75 men [54.3%]) with an admission median (IQR) Glasgow Coma Scale score of 9 (6-12) were studied. The median (IQR) delay between ICU admission and MRI was 1 (1-7) days. At 90 days, 95 patients (68.8%) had a poor outcome, including 16 deaths (11.6%). The presence of fluid-attenuated inversion recovery MRI signal abnormalities in more than 3 brain lobes (odds ratio [OR], 25.71; 95% CI, 1.21-554.42), age older than 60 years (OR, 7.62; 95% CI, 2.02-28.91), and the presence of diffusion-weighted MRI signal abnormalities in the left thalamus (OR, 6.90; 95% CI, 1.12-43.00) were independently associated with poor outcome. Machine learning models identified bilateral diffusion abnormalities as an additional factor associated with poor outcome (34 of 39 patients [87.2%] with bilateral abnormalities had poor outcomes) and confirmed the functional burden of left thalamic lesions, particularly in older patients (all 11 patients aged >60 years had left thalamic lesions). These findings suggest that in adult patients with HSE requiring ICU admission, extensive MRI changes in the brain are independently associated with poor functional outcome at 90 days. Thalamic diffusion signal changes were frequently observed and were associated with poor prognosis, mainly in older patients.

White Matter Hyperintensities Are Associated With Severity of Essential Tremor in the Elderly.

Background: Essential tremor (ET) occurs with steeply increasing prevalence in the elderly, and apart from disease duration, age is independently associated with an increase of tremor amplitude and a decrease of frequency. White matter hyperintensities (WMHs) are a common finding in the elderly, and their role in the pathophysiology of ET is unknown. The aims of this study were to examine whether ET patients differ in their total or region-specific WMH volumes from healthy controls and to determine the impact of WMH on tremor characteristics.Methods: A total of 47 elderly ET patients with a mean age of 72 years and 39 age-matched healthy controls underwent a thorough clinical assessment and 3T MRI. Total WMH volumes were derived from T2-weighted fluid-attenuated inversion recovery (FLAIR) MR images. Additionally, region of interest-based WMH volumes for the Johns Hopkins University (JHU) white matter tracts and labels were calculated, and WMHs were assessed semiquantitatively using the Fazekas scale.Results: Essential tremor patients and healthy controls did not differ in their total or tract-specific WMH volumes or Fazekas scores. However, WMH volume was significantly positively correlated with tremor severity on the TETRAS scale, and there was a significant negative correlation with the mean accelerometric tremor frequency. In a multiple linear regression model including disease duration, age, and age-adjusted total WMH volume, only the WMH volume significantly predicted tremor severity, while age and disease duration were not significant.Conclusion: We found evidence for a direct association between WMH volume and tremor severity. If confirmed by larger studies, our findings could explain the well-known relation between age and tremor severity.