Michael Linetsky

Delayed intravenous contrast-enhanced 3D FLAIR MRI in Meniere’s disease: correlation of quantitative measures of endolymphatic hydrops with hearing

OBJECTIVE Using three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging (3D-FLAIR MRI), our goal was to correlate quantifiable measures of endolymphatic hydrops (EH) with auditory function in the setting of Menieres disease (MD). MATERIALS AND METHODS Forty-one ears were analyzed in 21 subjects (12 ears with MD, 29 without MD). Vestibular endolymphatic space size measurements obtained with two different techniques were referenced against clinical data. RESULTS EH was better evaluated on 3D maximum intensity projections (MIPs) than on two-dimensional (2D) images. Using MIPs, quantitative assessments EH correlated with severity of hearing impairment. CONCLUSION 3D MIPs were superior to 2D images for evaluating EH in the setting of MD.

Arterial Spin-Labeling Perfusion MRI Stratifies Progression-Free Survival and Correlates with Epidermal Growth Factor Receptor Status in Glioblastoma

BACKGROUND AND PURPOSE: Glioblastoma is a common primary brain tumor with a poor but variable prognosis. Our aim was to investigate the feasibility of MR perfusion imaging by using arterial spin-labeling for determining the prognosis of patients with glioblastoma. MATERIALS AND METHODS: Pseudocontinuous arterial spin-labeling with 3D background-suppressed gradient and spin-echo was acquired before surgery on 53 patients subsequently diagnosed with glioblastoma. The calculated CBF color maps were visually evaluated by 3 independent readers blinded to patient history. Pathologic and survival data were correlated with CBF map findings. Arterial spin-labeling values in tumor tissue were also quantified by using manual fixed-size ROIs. RESULTS: Two perfusion patterns were characterized by visual evaluation of CBF maps on the basis of either the presence (pattern 1) or absence (pattern 2) of substantial hyperperfused tumor tissue. Evaluation of the perfusion patterns was highly concordant among the 3 readers (κ = 0.898, P < .001). Pattern 1 (versus pattern 2) was associated with significantly shorter progression-free survival by Kaplan-Meier analysis (median progression-free survival of 182 days versus 485 days, P < .01) and trended with shorter overall survival (P = .079). There was a significant association between pattern 1 and epidermal growth factor receptor variant III expression (P < .01). CONCLUSIONS: Qualitative evaluation of arterial spin-labeling CBF maps can be used to stratify survival and predict epidermal growth factor receptor variant III expression in patients with glioblastoma.

Perfusion Deficits Detected by Arterial Spin-Labeling in Patients with TIA with Negative Diffusion and Vascular Imaging

The current definition of TIA calls for normal imaging including DWI. Here the authors used arterial spin-labeling perfusion to detect abnormalities in nearly 50 patients within 24 hours of symptom onset and in 36 controls. The sensitivity and specificity of ASL in TIA diagnosis was 55.8% and 90.7%, respectively, and in nearly 94% of readings abnormalities that matched the clinical neurologic deficits were identified by the 3 observers. Thus, ASL perfusion is promising in evaluating and understanding TIAs. BACKGROUND AND PURPOSE: A substantial portion of clinically diagnosed TIA cases is imaging-negative. The purpose of the current study is to determine if arterial spin-labeling is helpful in detecting perfusion abnormalities in patients presenting clinically with TIA. MATERIALS AND METHODS: Pseudocontinuous arterial spin-labeling with 3D background-suppressed gradient and spin-echo was acquired on 49 patients suspected of TIA within 24 hours of symptom onset. All patients were free of stroke history and had no lesion-specific findings on general MR, DWI, and MRA sequences. The calculated arterial spin-labeling CBF maps were scored from 1–3 on the basis of presence and severity of perfusion disturbance by 3 independent observers blinded to patient history. An age-matched cohort of 36 patients diagnosed with no cerebrovascular events was evaluated as a control. Interobserver agreement was assessed by use of the Kendall concordance test. RESULTS: Scoring of perfusion abnormalities on arterial spin-labeling scans of the TIA cohort was highly concordant among the 3 observers (W = 0.812). The sensitivity and specificity of arterial spin-labeling in the diagnosis of perfusion abnormalities in TIA was 55.8% and 90.7%, respectively. In 93.3% (70/75) of the arterial spin-labeling CBF map readings with positive scores (≥2), the brain regions where perfusion abnormalities were identified by 3 observers matched with the neurologic deficits at TIA onset. CONCLUSIONS: In this preliminary study, arterial spin-labeling showed promise in the detection of perfusion abnormalities that correlated with clinically diagnosed TIA in patients with otherwise normal neuroimaging results.

DTI of tuber and perituberal tissue can predict epileptogenicity in tuberous sclerosis complex

Objective: To evaluate whether diffusion tensor imaging (DTI) can predict epileptogenic tubers by measuring apparent diffusion coefficient (ADC), fractional anisotropy, axial diffusivity, and radial diffusivity in both tubers and perituberal tissue in pediatric patients with tuberous sclerosis complex (TSC) undergoing epilepsy surgery. Methods: We retrospectively selected 23 consecutive patients (aged 0.4–19.6 years, mean age of 5.2; 13 female, 10 male) who underwent presurgical DTI and subsequent surgical resection between 2004 and 2013 from the University of California–Los Angeles TSC Clinic. We evaluated presurgical examinations including video-EEG, brain MRI, 18F-fluorodeoxyglucose–PET, magnetic source imaging, and intraoperative electrocorticography for determining epileptogenic tubers. A total of 545 tubers, 33 epileptogenic and 512 nonepileptogenic, were identified. Two observers generated the regions of interest (ROIs) of tubers (ROItuber), the 4-mm-thick ring-shaped ROIs surrounding the tubers (ROIperituber), and the combined ROIs (ROItuber+perituber) in consensus and calculated maximum, minimum, mean, and median values of each DTI measure in each ROI for all tubers. Results: The Mann–Whitney U test demonstrated that the epileptogenic group showed higher maximum ADC and radial diffusivity values in all ROIs, and that maximum ADC in ROItuber+perituber showed the strongest difference (p = 0.001). Receiver operating characteristic analysis demonstrated that maximum ADC measurements in ROItuber+perituber (area under curve = 0.68 ± 0.05, p < 0.001) had 81% sensitivity and 44% specificity for correctly identifying epileptogenic tubers with a cutoff value of 1.32 μm2/ms. Conclusions: DTI analysis of tubers and perituberal tissue may help to identify epileptogenic tubers in presurgical patients with TSC more easily and effectively than current invasive methods.

Intracochlear schwannoma presenting as diffuse cochlear enhancement: diagnostic challenges of a rare cause of deafness

Intracochlear schwannoma is a rare, treatable, cause of unilateral hearing loss. Due to the small size, position, and variable clinical and imaging features, diagnosis presents a significant challenge and is often delayed. We present a case of a patient with an intracochlear schwannoma presenting as a diffuse enhancement of the cochlea, mimicking an infectious or inflammatory process. The absence of focal nodularity in this lesion on multiple high-resolution MRI examinations led to a delay of over 3 years from the patient’s initial presentation to surgical diagnosis. Clinical history and examination, imaging features, pathologic findings, and surgical management options are described.

Prevalence of Herniation and Intracranial Shift on Cranial Tomography in Patients With Subarachnoid Hemorrhage and a Normal Neurologic Examination

OBJECTIVES Patients frequently present to the emergency department (ED) with headache. Those with sudden severe headache are often evaluated for spontaneous subarachnoid hemorrhage (SAH) with noncontrast cranial computed tomography (CT) followed by lumbar puncture (LP). The authors postulated that in patients without neurologic symptoms or signs, physicians could forgo noncontrast cranial CT and proceed directly to LP. The authors sought to define the safety of this option by having senior neuroradiologists rereview all cranial CTs in a group of such patients for evidence of brain herniation or midline shift. METHODS This was a retrospective study that included all patients with a normal neurologic examination and nontraumatic SAH diagnosed by CT presenting to a tertiary care medical center from August 1, 2001, to December 31, 2004. Two neuroradiologists, blinded to clinical information and outcomes, rereviewed the initial ED head CT for evidence of herniation or midline shift. RESULTS Of the 172 patients who presented to the ED with spontaneous SAH diagnoses by cranial CT, 78 had normal neurologic examinations. Of these, 73 had initial ED CTs available for review. Four of the 73 (5%; 95% confidence interval [CI] = 2% to 13%) had evidence of brain herniation or midline shift, including three (4%; 95% CI = 1% to 12%) with herniation. In only one of these patients was herniation or shift noted on the initial radiology report. CONCLUSIONS Awake and alert patients with a normal neurologic examination and SAH may have brain herniation and/or midline shift. Therefore, cranial CT should be obtained before LP in all patients with suspected SAH.

C-terminally truncated form of αB-crystallin is associated with IDH1 R132H mutation in anaplastic astrocytoma

Malignant gliomas are the most common human primary brain tumors. Point mutation of amino acid arginine 132 to histidine (R132H) in the IDH1 protein leads to an enzymatic gain-of-function and is thought to promote gliomagenesis. Little is known about the downstream effects of the IDH1 mutation on protein expression and how and whether changes in protein expression are involved in tumor formation or propagation. In the current study, we used 2D DIGE (difference gel electrophoresis) and mass spectrometry to analyze differences in protein expression between IDH1R132H mutant and wild type anaplastic (grade III) astrocytoma from human brain cancer tissues. We show that expression levels of many proteins are altered in IDH1R132H mutant anaplastic astrocytoma. Some of the most over-expressed proteins in the mutants include several forms of αB-crystallin, a small heat-shock and anti-apoptotic protein. αB-crystallin proteins are elevated up to 22-fold in IDH1R132H mutant tumors, and αB-crystallin expression appears to be controlled at the post-translational level. We identified the most abundant form of αB-crystallin as a low molecular weight species that is C-terminally truncated. We also found that overexpression of αB-crystallin can be induced by transfecting U251 human glioblastoma cell lines with the IDH1R132H mutation. In conclusion, the association of a C-terminally truncated form of αB-crystallin protein with the IDH1R132H mutation is a novel finding that could impact apoptosis and stress response in IDH1 mutant glioma.

Application of arterial spin labeling perfusion MRI to differentiate benign from malignant intracranial meningiomas

PURPOSE Differentiating WHO grade I-III of meningioma by non-invasive imaging is challenging. This study investigated the potential of MR arterial spin labeling (ASL) to establish tumor grade in meningioma patients. MATERIAL AND METHODS Pseudo-continuous ASL with 3D background suppressed gradient and spin echo (GRASE) was acquired on 54 patients with newly diagnosed or recurrent intracranial meningioma. Perfusion patterns characterized in CBF color maps were independently evaluated by three neuroradiologists blinded to patient history, and correlated with tumor grade from histo-pathological review. RESULTS Three perfusion patterns could be discerned by visual evaluation of CBF maps. Pattern 1 consisted of homogeneous hyper-perfusion of the entire tumor; pattern 2 demonstrated heterogeneous hyper-perfusion; pattern 3 showed no substantial hyper-perfusion. Evaluation of the perfusion patterns was highly concordant among the three readers (Kendall W=0.9458, P<0.0001). Pattern 1 was associated with WHO Grade I meningioma of (P<0.0001). Patterns 2 and 3 were predictive of WHO Grade II and III meningioma (P<0.0001), with an odds ratio (OR, versus pattern 1) of 49.6 (P<0.01) in a univariate analysis, and an OR of 186.4 (P<0.01) in a multivariate analysis. CONCLUSION Qualitative evaluation of ASL CBF maps can help differentiate benign (WHO Grade I) from higher grade (WHO Grade II and III) intracranial meningiomas, potentially impacting therapeutic strategy.

Challenging Diagnosis and Surgical Management of a Symptomatic Sellar Spine.

BACKGROUND The sellar spine is a rare, bony growth that typically arises from the dorsum sellae. Few cases have been described in the literature thus far, and most are asymptomatic and incidentally found. We describe the case of a 19-year-old female in whom a sellar spine was noted to be associated with pituitary glandular deformation and symptomatic optic apparatus compression. CASE DESCRIPTION The medical records including clinical data, pathologic, and imaging findings pertaining to the single patient presented herein were retrospectively reviewed. The patient underwent resection of the hyperostotic sellar spine for decompression of the optic chiasm and pituitary gland via an endoscopic endonasal approach. She immediately reported complete resolution of her bitemporal visual deficits. Her headaches completely resolved, she had no further transient visual deficits, and all other prior presenting symptoms and signs resolved. CONCLUSION Recognition of a sellar spine can be elusive, and removal of a symptomatic one may be technically challenging. It is important to consider this entity in the differential diagnosis of a patient with headaches and bitemporal visual deficits.