MRI findings of elevated intracranial pressure in cerebral venous thrombosis versus idiopathic intracranial hypertension with transverse sinus stenosis.

PURPOSE: To determine whether MRI signs suggesting elevated intracranial pressure (ICP) are preferentially found in patients with idiopathic intracranial hypertension (IIH) than in those with cerebral venous thrombosis (CVT). METHODS: Among 240 patients who underwent standardized contrast-enhanced brain MRI/MRV at our institution between 9/2009 and 9/2011, 60 with abnormal imaging findings on MRV were included: 27 patients with definite IIH, 2 patients with presumed IIH, and 31 with definite CVT. Medical records were reviewed, and imaging studies were prospectively evaluated by the same neuroradiologist to assess for presence or absence of transverse sinus stenosis (TSS), site of CVT if present, posterior globe flattening, optic nerve sheath dilation/tortuosity, and the size/appearance of the sella turcica. RESULTS: 29 IIH patients (28 women, 19 black, median-age 28, median-body mass index, 34) had bilateral TSS. 31 CVT patients (19 women, 13 black, median-age 46, median-BMI 29) had thrombosis of the sagittal (3), sigmoid (3), cavernous (1), unilateral transverse (7), or multiple (16) sinuses or cortical veins (1). Empty/partially-empty sellae were more common in IIH (3/29 and 24/29) than in CVT patients (1/31 and 19/31) (p<0.001). Flattening of the globes and dilation/tortuosity of the optic nerve sheaths were more common in IIH (20/29 and 18/29) than in CVT patients (13/31 and 5/31) (p<0.04). CONCLUSION: Although abnormal imaging findings suggestive of raised ICP are more common in IIH, they are not specific for IIH and are found in patients with raised ICP from other causes such as CVT.

Clinical course of idiopathic intracranial hypertension with transverse sinus stenosis.

OBJECTIVE: Transverse sinus stenosis (TSS) is common in idiopathic intracranial hypertension (IIH), but its effect on the course and outcome of IIH is unknown. We evaluated differences in TSS characteristics between patients with IIH with "good" vs. "poor" clinical courses. METHODS: All patients with IIH seen in our institution after September 2009 who underwent a high-quality standardized brain magnetic resonance venogram (MRV) were included. Patients were categorized as having a good or poor clinical course based on medical record review. The location and percent of each TSS were determined for each patient, and were correlated to the clinical outcome. RESULTS: We included 51 patients. Forty-six patients had bilateral TSS. The median average percent stenosis was 56%. Seventy-one percent of patients had stenoses >50%. Thirty-five of the 51 patients (69%) had no final visual field loss. Eight patients (16%) had a clinical course classified as poor. There was no difference in the average percent stenosis between those with good clinical courses vs those with poor courses (62% vs. 56%, p = 0.44). There was no difference in the percent stenosis based on the visual field grade (p = 0.38). CSF opening pressure was not associated with either location or degree of TSS. CONCLUSION: TSS is common, if not universal, among patients with IIH, and is almost always bilateral. There is no correlation between the degree of TSS and the clinical course, including visual field loss, among patients with IIH, suggesting that clinical features, not the degree of TSS, should be used to determine management in IIH.

Does bilateral transverse cerebral venous sinus stenosis exist in patients without increased intracranial pressure?

OBJECTIVE: Transverse cerebral venous sinus stenosis (TSS) is common among patients with idiopathic intracranial hypertension. TSS likely also exists among individuals with normal intracranial pressure (ICP) but the prevalence is unclear. The goal of this study was to identify patients with incidental TSS and normal ICP and describe their characteristics. METHODS: Among 240 adult patients who underwent brain magnetic resonance imaging (MRI) with magnetic resonance venography (MRV) with contrast at our institution between September 2009 and September 2011, 44 had isolated TSS without further substantial imaging abnormality. Medical records were reviewed for symptoms of increased ICP, papilledema, cerebrospinal fluid (CSF) constituents and opening pressure (OP), and reason for brain imaging. Of these, 37 were excluded for confirmed or possible idiopathic intracranial hypertension. Of the remainder, 5 had CSF-OP≤25 cmH2O without papilledema, and 2 did not have measured ICP, but had no papilledema or symptoms of increased ICP. Imaging was re-interpreted to assess for signs suggestive of elevated ICP and to characterize the TSS further. RESULTS: All patients were women (mean age: 41, mean BMI: 37.1). CSF contents were normal, but OPs were at the upper limit of normal (22-25 cmH2O). Indications for MRI/MRV included query pituitary abnormality (1), migraine (4), and anomalous-appearing optic nerves (2). All had bilateral TSS. Six had short TSS and an empty sella; 1 had long TSS and no empty sella; 1 had flattening of the posterior sclera; 2 had prominence of peri-optic nerve CSF. CONCLUSION: Asymptomatic bilateral TSS exists in patients with ICP≤25 cmH2O, but is likely uncommon. CSF-OP was at the upper limit of normal in our patients, who also had other radiologic signs suggestive (but not specific) of chronically-raised ICP. Findings of bilateral TSS on imaging should prompt funduscopic examination for papilledema.

Vitreous hemorrhage secondary to optociliary shunt vessels from papilledema.

A 15-year-old adolescent girl with idiopathic intracranial hypertension was noted to have papilledema and optociliary shunt vessels. Medical management was controlling her symptoms, but vision deteriorated rapidly in the left eye secondary to a vitreous hemorrhage. Given the lack of any other cause for vitreous hemorrhage, it most likely originated from the shunt vessels. Optic nerve sheath fenestration was performed in an effort to promote regression of the papilledema and the shunt vessels. Our case illustrates a rare complication of optociliary shunt vessels in the setting of papilledema.