Value of prominent flow voids without cord edema in the detection of spinal arteriovenous fistulae

Purpose: To determine the prevalence of spinal dural arteriovenous fistulae (SDAVF) in patients presenting with prominent vascular flow voids on imaging without other imaging findings suggestive of SDAVF. Methods: We retrospectively identified patients from January 1, 2005 to March 1, 2012 who underwent spinal angiography for suspected SDAVF with prominent vascular flow voids on prior imaging. We excluded patients with other major spinal pathology or other imaging findings of SDAVF including cord hyperintensity, enhancement, or expansion. We calculated the proportion of patients with positive findings for SDAVF on angiography and evaluated the prevalence of SDAVF for this finding alone and in correlation with clinical findings. Results: 18 patients underwent spinal angiography for prominent flow voids on imaging without other spinal pathology or imaging findings of SDAVF. Three had a SDAVF detected on angiography. The prevalence of SDAVF in this population was low, only 17% (95% CI 6-39%). All of the patients with positive angiography findings had myelopathy, increasing the prevalence to 100% if the additional clinical finding of myelopathy was present. Conclusions: Prominent flow voids without other imaging findings suggestive of SDAVF is poorly predictive of the presence of a SDAVF, unless myelopathy is present clinically. © 2014 Alhilali et al

Neurodegenerative Changes after Mild Traumatic Brain Injury

A link between mild traumatic brain injury (mTBI) and neurodegenerative diseases, specifically Alzheimer\u27s disease and chronic traumatic encephalopathy (CTE), has long been suspected. Shared clinical symptomology - most notably the prominent role of central auditory dysfunction and sleep-wake disturbances in both disease states - and similar findings on postmortem pathological examination has further reinforced suspected commonality between these seemingly disparate entities. However, conventional imaging techniques, including computed tomography and anatomic magnetic resonance, are unable to detect the symptomatic injuries in mTBI patients and therefore detection of neurodegenerative changes in vivo has previously not been reported. Recent research using diffusion tensor imaging, a novel imaging technique, and focused on patient-reported symptoms has for the first time demonstrated imaging findings in mTBI patients in vivo that are strikingly similar to Alzheimer\u27s dementia and CTE. Moving forward, research will focus on identifying what renders certain patients with mTBI susceptible to developing full-fledged Alzheimer\u27s disease and CTE later in life

Evaluation of tentorial length and angle in sleep-wake disturbances after mild traumatic brain injury

OBJECTIVE: The purpose of this study was to determine if there is an association between tentorial length and angle and sleep-wake disturbances in patients with mild traumatic brain injury (TBI). MATERIALS AND METHODS: MRI examinations of the brain of 34 consecutive patients with mild TBI with sleep-wake disturbance and 30 patients with mild TBI without sleep-wake disturbance were retrospectively reviewed. The length of the tentorium on a sagittal T1-weighted image (tentorial length) and the angle formed between the tentorium and a line through the foramen magnum (tentorial angle) were measured. Results were correlated with both neuropsychologic testing and any sleep-wake disturbance. RESULTS: No significant difference existed between patients with and without sleep-wake disturbances in terms of age (p=0.44), sex (p=0.13), Immediate Post-Concussion Assessment Cognitive Test total symptom score (p=0.10), verbal memory score (p=0.32), visual memory score (p=0.31), processing speed (p=0.15), or reaction time (p=0.84). Tentorial length in patients with mild TBI with sleep-wake disturbances was significantly longer than patients with mild TBI without sleep-wake disturbances (p\u3c0.01), and tentorial angle was significantly smaller (p\u3c0.01). Tentorial angle was inversely correlated with length of time to recovery (p=0.002), and tentorial length was directly correlated with length of time to recovery (p\u3c0.001). CONCLUSION: Among patients with mild TBI with similar cognitive function and symptom severity, those with sleep-wake disturbances have significantly longer tentorial length with a flatter angle than do patients with mild TBI without sleep symptoms, with length of time to recovery being directly correlated with tentorial length and indirectly correlated with tentorial angle. Direct impact between the tentorium and the pineal gland during mild TBI may lead to pineal gland injury, disruption of melatonin homeostasis, and sleep-wake disturbances

A multi-disciplinary model of risk factors for fatal outcome in posterior reversible encephalopathy syndrome

PURPOSE: To evaluate the relative impact of clinical data, imaging findings, and CSF laboratory values on clinical outcome in patients with posterior reversible encephalopathy syndrome (PRES). METHODS: 47 patients with PRES who underwent a lumbar puncture were retrospectively evaluated. Fatal outcome was defined as death directly ascribed to PRES toxicity. Univariate and multivariate analyses were used to evaluate the association between fatal outcome and clinical factors (demographics, PRES etiology), imaging findings (signal abnormality severity, atypical distribution, restricted diffusion, hemorrhage, enhancement, angiographic abnormalities), and lumbar puncture results (appearance, cell count, glucose, protein, culture results). RESULTS: Nine patients (19.1%) had a fatal outcome. Odds of a fatal outcome increased nearly 5-fold with hemorrhage on imaging (Adjusted Odds Ratio (AOR) 4.8, 95% CI 3.8-6.0, p=0.03) and nearly doubled with low CSF glucose (AOR 1.9, 95% CI 1.5-2.5, p=0.02). Hypertensive encephalopathy as an etiology was associated with a fatal outcome (AOR 1.6, 95% CI 1.3-2.9, p=0.02), while toxemia of pregnancy was protective, with a 75% decreased risk (AOR 0.25, 95% CI 0.15-0.43, p=0.02). CONCLUSION: Clinical, imaging, and CSF laboratory findings all influence outcome in PRES, with a low CSF glucose, hypertensive encephalopathy, and imaging findings of hemorrhage associated with increased risk of fatal outcome

Symptomatic white matter changes in mild traumatic brain injury resemble pathologic features of early Alzheimer dementia

PURPOSE: To evaluate white matter integrity in patients with mild traumatic brain injury (TBI) who did not have morphologic abnormalities at conventional magnetic resonance (MR) imaging with diffusion-tensor imaging to determine any relationship between patterns of white matter injury and severity of postconcussion symptoms. MATERIALS AND METHODS: The institutional review board approved this study, with waiver of informed consent. Diffusion-tensor images from 64 consecutive patients with mild TBI obtained with conventional MR imaging were evaluated retrospectively. Fractional anisotropy (FA) maps were generated as a measure of white matter integrity. All patients underwent a neurocognitive evaluation. Correlations between skeletonized FA values in white matter, total concussion symptom score, and findings of sleep and wake disturbances were analyzed with regression analysis that used tract-based spatial statistics. RESULTS: Total concussion symptom scores varied from 2 to 97 (mean ± standard deviation, 32.7 ± 24.4), with 34 patients demonstrating sleep and wake disturbances. Tract-based spatial statistics showed a significant correlation between high total concussion symptom score and reduced FA at the gray matter-white matter junction (P \u3c .05), most prominently in the auditory cortex (P \u3c .05). FA in the parahippocampal gyri was significantly decreased in patients with sleep and wake disturbances relative to patients without such disturbances (0.26 and 0.37, respectively; P \u3c .05). CONCLUSION: The distribution of white matter abnormalities in patients with symptomatic mild TBI is strikingly similar to the distribution of pathologic abnormalities in patients with early Alzheimer dementia, a finding that may help direct research strategies

Evaluation of a limited three-slice head CT protocol for monitoring patients with ventriculoperitoneal shunts

OBJECTIVE: Patients with a ventriculoperitoneal shunt for the management of hydrocephalus often undergo multiple head CT examinations for assessment of shunt malfunction. The purpose of this study was to evaluate whether a limited three-slice CT protocol would consistently provide adequate information for the diagnosis of shunt malfunction with a decrease in effective dose. MATERIALS AND METHODS: The study group included 231 unenhanced head CT examinations performed on 128 patients with shunts for hydrocephalus. The original contiguous CT images were reviewed retrospectively. A theoretic limited three-slice study was then created from the original complete CT study and separately reviewed. This limited three-slice study was created by using the lateral topographic image to select three axial locations as follows: midpoint between foramen magnum and vertex, top of the mastoid air cells, and orbital roof. The limited study was graded for parameters of image adequacy with the original full protocol study as the reference standard. RESULTS: Twenty-four of the 231 (10.4%) full studies had findings consistent with shunt failure; all 231 studies would have been correctly categorized with the limited three-slice protocol. The sensitivity of three-slice CT for identifying the ventricular system was 91.6% and for identifying the catheter tip, 93.5%. Limited-slice CT examination would have resulted in greater than 90% mean dose reduction in both adult and pediatric populations. CONCLUSION: Unenhanced head CT with a limited-slice protocol provides adequate diagnostic information for the diagnosis of shunt malfunction with a greater than 90% reduction in effective dose

Assessment of rates of acute adverse reactions to gadobenate dimeglumine: review of more than 130,000 administrations in 7.5 years

OBJECTIVE: The purpose of this study was to determine the incidence of adverse events associated with gadobenate dimeglumine over 7.5 years in a major hospital system consisting of both academic and community hospitals. SUBJECTS AND METHODS: As part of a regular and continuous prospective quality assurance project, MRI technologists contemporaneously recorded all gadolinium-based contrast administrations and any associated adverse reactions, including type of reaction and treatment rendered, between August 1, 2005, and March 14, 2013. Weekly data review was performed by the director of MRI services, who evaluated data both by individual site and by comparison among the participating hospitals and sites within the hospital system. Comparison between reaction rates at different sites was performed with a chi-square test. RESULTS: Over 7.5 years, 132,252 doses of gadobenate dimeglumine were administered, and 236 reactions were recorded (0.18% of contrast-enhanced examinations). Of these, 133 (56.4% of all adverse reactions) required treatment and 12 (5.1%) qualified as serious. Reaction rates were significantly different between academic (0.23%) and community (0.07%) hospitals (p\u3c0.001). Reaction rates were higher in the initial years of the study, tapering to a lower baseline rate, which was maintained over more than 5 years. The findings were consistent with the Weber and Lalli effects reported in the literature on other pharmaceutical agents. CONCLUSION: Rates of adverse reactions to gadobenate dimeglumine recorded over 7.5 years were comparable to those reported for other gadolinium-based contrast agents examined over smaller time ranges and populations. The findings reinforce the relatively robust safety profile of this agent

Angioglioma misdiagnosed as encephalomalacia on magnetic resonance imaging for over a decade

We report a case of intractable seizures secondary to an angioglioma that was misdiagnosed as post-traumatic encephalomalacia for over a decade, with a discussion of the radiological findings and a review of the literature

Detection of central white matter injury underlying vestibulopathy after mild traumatic brain injury

PURPOSE: To determine if central axonal injury underlies vestibulopathy and ocular convergence insufficiency after mild traumatic brain injury (TBI) by using tract-based spatial statistics (TBSS) analysis of diffusion-tensor imaging (DTI). MATERIALS AND METHODS: The institutional review board approved this study, and the requirement to obtain informed consent was waived. Diffusion-tensor images were retrospectively reviewed in 30 patients with mild TBI and vestibular symptoms and 25 patients with mild TBI and ocular convergence insufficiency. Control subjects consisted of 39 patients with mild TBI without vestibular abnormalities and 17 patients with mild TBI and normal ocular convergence. Fractional anisotropy (FA) maps were generated as a measure of white matter integrity and were analyzed with TBSS regression analysis by using a general linear model. DTI abnormalities were correlated with symptom severity, neurocognitive test scores, and time to recovery with the Pearson correlation coefficient. RESULTS: Compared with control subjects, patients with mild TBI and vestibular symptoms had decreased neurocognitive test scores (P \u3c .05) and FA values in the cerebellum and fusiform gyri (P \u3c .05). Patients with ocular convergence insufficiency had diminished neurocognitive test scores (P \u3c .05) and FA values in the right anterior thalamic radiation and right geniculate nucleus optic tracts (P \u3c .0001). Cerebellar injury showed an inverse correlation with recovery time (R = -0.410, P = .02). Anterior thalamic radiation injury showed correlation with decreased processing speed (R = 0.402, P \u3c .05). CONCLUSION: DTI findings in patients with mild TBI and vestibulopathy support the hypothesis that posttraumatic vestibulopathy has a central axonal injury component. Peripheral vestibular structures were not assessed, and a superimposed peripheral contribution may exist. DTI evaluation of central vestibular structures may provide a diagnostic imaging tool in these patients and a quantitative biomarker to aid in prognosis