Transverse Sinus Stenosis Is the Most Sensitive MR Imaging Correlate of Idiopathic Intracranial Hypertension.

BACKGROUND AND PURPOSE: Patients with idiopathic intracranial hypertension have transverse sinus stenosis on gadolinium-bolused MRV, but other MR imaging signs are less consistently seen. Our aim was to demonstrate that transverse sinus stenosis could be identified on conventional MR imaging, and this identification would allow improved diagnostic sensitivity to this condition. MATERIALS AND METHODS: MR imaging and MRV images from 63 patients with idiopathic intracranial hypertension and 96 controls were reviewed by using 3 independent procedures. MRV images were graded for the presence and degree of stenosis of the transverse sinus. Postgadolinium coronal T1-weighted sequences were evaluated independent of MRV. The dimensions of the proximal and distal transverse sinus were measured from the MRV examinations, and the cross-sectional area of the transverse sinus was calculated. Correlation among the 3 modes of evaluation of the transverse sinus was conducted by using Wilcoxon/Kruskal-Wallis, Pearson, and Spearman ρ nonparametric statistical techniques. RESULTS: Transverse sinus stenosis was identified bilaterally on MRV in 94% of patients with idiopathic intracranial hypertension and in 3% of controls. On coronal T1 postgadolinium MR images, transverse sinus stenosis was identified in 83% of patients with idiopathic intracranial hypertension and 7% of controls. Previously described MR imaging signs of intracranial hypertension were identified in 8%-61% of patients with idiopathic intracranial hypertension. Correlation among the 3 modes of evaluation was highly significant (P < .0001). CONCLUSIONS: Even without the assistance of an MRV sequence, neuroradiologists can validly identify bilateral transverse sinus stenosis in patients with intracranial hypertension more reliably than other previously described MR imaging findings in this condition. We conclude that transverse sinus stenosis is the most useful and sensitive imaging indicator of this disease state.

Increased Curvature of the Tentorium Cerebelli in Idiopathic Intracranial Hypertension.

BACKGROUND AND PURPOSE: Transverse sinus effacement is detectable on MRV examinations in almost all patients with idiopathic intracranial hypertension. This effacement of the transverse sinus is presumed to be mediated by elevation of intracranial pressure, resulting in compression and inward collapse of the dural margins of the sinus. We sought to establish whether supratentorial broad-based downward deformity of the tentorium might explain transverse sinus effacement in idiopathic intracranial hypertension. MATERIALS AND METHODS: MRV examinations of 53 adult patients with idiopathic intracranial hypertension were reviewed retrospectively and compared with 58 contemporaneously acquired controls. The curvature of the tentorium with reference to a line connecting the transverse sinus laterally with the confluence of the tentorial leaves medially was calculated as a segment of a circle. The height and area of the segment and the angle subtended by the midpoint of the tentorium from the falx were calculated. RESULTS: The height and area of the segment described by the chord connecting the transverse sinus with the apex of the tentorial confluence and subtended midtentorial angle were greater in the idiopathic intracranial hypertension group; this finding supports the hypothesis that increased tentorial bowing is present in idiopathic intracranial hypertension. CONCLUSIONS: Increased bowing of the tentorium in patients with idiopathic intracranial hypertension compared with controls is a new observation, lending itself to new hypotheses on the nature and localization of elevated intracranial pressure in idiopathic intracranial hypertension. Bowing of the tentorium may play a part in distorting the contour of the transverse sinuses, resulting, at least in part, in the effacement of the transverse sinuses in idiopathic intracranial hypertension.

American Society of Functional Neuroradiology-Recommended fMRI Paradigm Algorithms for Presurgical Language Assessment.

INTRODUCTION: Functional MR imaging is increasingly being used for presurgical language assessment in the treatment of patients with brain tumors, epilepsy, vascular malformations, and other conditions. The inherent complexity of fMRI, which includes numerous processing steps and selective analyses, is compounded by institution-unique approaches to patient training, paradigm choice, and an eclectic array of postprocessing options from various vendors. Consequently, institutions perform fMRI in such markedly different manners that data sharing, comparison, and generalization of results are difficult. The American Society of Functional Neuroradiology proposes widespread adoption of common fMRI language paradigms as the first step in countering this lost opportunity to advance our knowledge and improve patient care. LANGUAGE PARADIGM REVIEW PROCESS: A taskforce of American Society of Functional Neuroradiology members from multiple institutions used a broad literature review, member polls, and expert opinion to converge on 2 sets of standard language paradigms that strike a balance between ease of application and clinical usefulness. ASFNR RECOMMENDATIONS: The taskforce generated an adult language paradigm algorithm for presurgical language assessment including the following tasks: Sentence Completion, Silent Word Generation, Rhyming, Object Naming, and/or Passive Story Listening. The pediatric algorithm includes the following tasks: Sentence Completion, Rhyming, Antonym Generation, or Passive Story Listening. DISCUSSION: Convergence of fMRI language paradigms across institutions offers the first step in providing a "Rosetta Stone" that provides a common reference point with which to compare and contrast the usefulness and reliability of fMRI data. From this common language task battery, future refinements and improvements are anticipated, particularly as objective measures of reliability become available. Some commonality of practice is a necessary first step to develop a foundation on which to improve the clinical utility of this field.

Intracranial imaging of uncommon diseases is more frequently reported in clinical publications than in radiology publications.

BACKGROUND AND PURPOSE: Descriptions of uncommon diseases with intracranial imaging abnormalities are often difficult to find in the radiology literature. We hypothesized that reported imaging findings of such conditions in the recent literature were more frequent in clinical compared with radiology journals. MATERIALS AND METHODS: PubMed searches from December 1, 2007 to December 1, 2012 were performed for 5 uncommon CNS diseases with intracranial imaging manifestations: 1) Susac syndrome; 2) amyloid ß-related angiitis; 3) Parry-Romberg syndrome/en coup de sabre; 4) transient lesion of the splenium of the corpus callosum; and 5) reversible cerebral vasoconstriction syndrome. Articles were classified as a case report, case series, or original research. Journals were categorized as radiology or clinical. The 1- and 5-year Impact Factors of the journals were recorded. RESULTS: Two hundred two articles were identified for the 5 diseases, including 151 (74%) case reports, 26 case series (13%), and 25 original research articles (13%); 179 (89%) were published in nonradiology journals, compared with 23 (11%) in radiology journals. There was no significant difference between the mean 1- and 5-year Impact Factors of the radiology and clinical journals. CONCLUSIONS: Recent reports of the selected uncommon diseases with intracranial manifestations are more frequent in clinical journals when compared with dedicated radiology publications. Most publications are case reports. Radiologists should review both radiology and clinical journals when reviewing imaging features of uncommon diseases affecting the brain. Lack of reporting on such disease in the radiology literature may have significant practice, educational, and research implications for the radiology community.

Stroke-like migraine attacks after radiation therapy (SMART) syndrome is not always completely reversible: a case series.

We retrospectively reviewed clinical and imaging findings in 11 patients with stroke-like migraine attacks after radiation therapy (SMART) syndrome to better understand this disorder previously thought to be reversible. Six men and 5 women had complex bouts of neurologic impairment beginning, on average, 20 years after cerebral irradiation. All had characteristic, unilateral gyriform enhancement on MR imaging that developed within 2-7 days and typically resolved in 2-5 weeks. Unlike prior reports, 45% had incomplete neurologic recovery manifesting as dysphasia, cognitive impairment, or hemiparesis. The remaining 55% recovered completely over an average of 2 months. Three of 11 patients developed cortical laminar necrosis. Brain biopsies in 4 of 11 did not demonstrate a specific pathologic substrate. These additional 11 patients contribute to the understanding of variability in stroke-like migraine attacks after radiation therapy syndrome, which often but not uniformly manifests with headaches and seizures, demonstrates a typical evolution of imaging findings, and may result in permanent neurologic and imaging sequelae.

Position-related variability of CSF opening pressure measurements.

BACKGROUND AND PURPOSE: Normative data for CSF OP have previously been established with patients in the LD position. During fluoroscopically guided LP procedures, radiologists frequently obtain these OP measurements with patients prone. In this prospective study, our goal was to determine the variability of OP measurements as a function of patient positioning and to assess whether there is a relationship with patient BMI. MATERIALS AND METHODS: Consecutive patients reporting for fluoroscopically guided LP or myelography were enrolled. OP was measured with the patient in 3 positions, with the order of the technique randomized: prone with table flat, prone with table tilted until the hub of the needle was at the level of the right atrium, and LD with the needle hub at the level of the spinal canal. The BMI of each patient was calculated. The Wilcoxon signed-rank test and linear regression analysis with bivariate fit of difference were used for analysis. RESULTS: OP measurements with the patient in the prone position were significantly elevated compared with those in the LD position, with mean differences of 2.7 (P<.001) and 1.6 cm H2O, (P=.017) for prone flat and prone tilted, respectively. There was no significant difference in OP measurements for the prone flat versus prone tilted positions (P=.20). There was no correlation between BMI and observed differences (LD-flat: R2=0.00028; LD-tilt: R2=0.00038; prone-tilt: R2=0.00000020). CONCLUSIONS: Measuring OP with the patient in the prone position may result in overestimation of CSF pressure. Table tilt did not significantly impact mean prone OP. Radiologists should specify exact patient positioning when reporting OP measurements.

Irrigation nose: CT findings of paranasal sinus exostoses.

We report the case of a 57-year-old male who presented with recurrent sinus infections and frequent nasal irrigation. He was found at nasal endoscopy to have multiple outgrowths along his ethmoid and maxillary sinuses. Computed tomography (CT) showed multiple bony exostoses along these sinuses. We report the imaging findings of exostoses associated with sinonasal irrigation.

Cerebral venous sinus density on noncontrast CT correlates with hematocrit.

BACKGROUND AND PURPOSE: A positive correlation between HCT and CT attenuation of intravascular blood has long been assumed but has never been established by using substantial patient numbers and modern CT equipment. The purpose of this study was to determine whether apparent increased attenuation on CT in cerebral venous sinuses can be attributed to hemoconcentration alone and to assess whether sinus thrombosis can be differentiated from hemoconcentrated blood based on attenuation values alone. MATERIALS AND METHODS: We measured HUs in a region of interest within the confluence of dural venous sinuses in 166 unenhanced head CTs and correlated these data with HCT and HGB values in male and female patients aged 2 to 100 years. We then compared these data with similar measurements in 8 patients with recent venous sinus thrombosis. Two-tailed t test and linear regression analyses were performed to evaluate HGB and HCT between groups and with measured CT attenuation of intravascular blood, respectively. RESULTS: A statistically significant relationship was noted between both HCT and HGB with CT attenuation. Seven of 8 patients with sinus thrombosis had attenuation values >70, but none of the normal subjects had HUs >70. CONCLUSIONS: Hemoconcentration correlates with CT attenuation in cerebral venous sinuses. Our findings suggest that comparing the ratio of HUs to HCT may be useful in gauging concern for sinus thrombosis.

MR imaging of central nervous system Whipple disease: a 15-year review.

CNS WD is fatal if antibiotics are not begun early, but knowledge regarding the variety of presentations on MR imaging is limited. In order to more effectively recognize this entity on MR imaging, the Mayo Clinic medical records were reviewed for subjects diagnosed with CNS WD from 1992-2006 who had also undergone MR imaging of the neuraxis. Seven subjects were identified and their imaging findings were reviewed by the authors. Four of 7 had head MR imaging findings indicative of WD. Two subjects demonstrated high T2 signal within the corticospinal tracts. CNS WD may demonstrate high T2 signal with minimal enhancement and no restricted diffusion, primarily in the midline of the midbrain, hypothalamus, and mesial temporal lobes and occasionally the corticospinal tracts. MR imaging may also be normal. Radiologists should be aware of these presentations and be prepared to mention CNS WD as a diagnostic possibility since early antibiotic therapy may significantly impact morbidity and mortality.

SMART: stroke-like migraine attacks after radiation therapy.

We describe two adults with stroke-like migraine attacks after radiation therapy (SMART syndrome), propose revised diagnostic criteria, and review the previously reported patients. 'SMART' is an acronym for a newly recognized syndrome which occurs as a delayed consequence of cerebral irradiation and consists of prolonged, unilateral, migrainous neurological symptoms with transient, dramatic cortical gadolinium enhancement of the affected cerebral hemisphere and is sometimes punctuated by generalized seizures and ipsilateral EEG slowing. Although the neurological symptoms can last for weeks, full recovery occurs. An appropriate evaluation should exclude alternative explanations.

Two cases of medically and surgically intractable SUNCT: a reason for caution and an argument for a central mechanism.

We report two cases of SUNCT that demonstrate the medically and surgically refractory nature of this disorder and support the hypothesis that the causative 'lesion' lies within the central nervous system. After both patients had failed medical therapies, the first underwent a glycerol rhizotomy, gammaknife radiosurgery and microvascular decompression of the trigeminal nerve. The second patient underwent gammaknife radiosurgery of the trigeminal root exit zone and two microvascular decompression surgeries. Neither patient benefited from these procedures. Currently, the first patient suffers from anaesthesia dolorosa and the second patient from unilateral deafness, chronic vertigo and dysequilibrium as a result of surgical trauma. These cases of SUNCT highlight the uncertainty regarding the role of surgery given the potential for significant morbidity. These cases also suggest that SUNCT originates and may be maintained from within the CNS and this central locus explains why SUNCT is not typically amenable to interventions aimed at the peripheral portion of the trigeminal nerve.

Electroconvulsive therapy and Friedreich's ataxia.

Friedreich's ataxia is commonly associated with depression. Treatment of the depression can be difficult due to numerous morbid medical conditions. ECT is a safe and effective treatment option.

Outcome of trigeminal nerve section in the treatment of chronic cluster headache.

Chronic cluster headache accounts for 10 to 15% of all patients with cluster headache and is often resistant to medical management. The authors followed 17 patients with intractable chronic cluster headache who underwent trigeminal nerve section. They found that trigeminal nerve section is an effective treatment with acceptable morbidity for a carefully selected group of patients.