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

Abstract

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.

Keywords: MRI; MRV; cerebral venous thrombosis; empty sella; idiopathic intracranial hypertension; venous hypertension.

FIGURE 1

Classification of pituitary height and morphology (adapted from Yuh et al.7). Grades I (normal) to V (no visible pituitary) are shown on mid-sagittal T1-weighted MRI images through the sella turcica: Grade I = normal; Grade II = mild superior concavity (less than 1/3 of the height of the sella); Grade III = moderate concavity (between 1/3 and 2/3 of the height of the sella); Grade IV = severe concavity (more than 2/3 of the height of the sella); Grade V = no visible pituitary tissue.

FIGURE 2

Technique used to measure the size of the sella turcica, the infundibulum, and the optic chiasm. For each patient, the measurements were made on a magnified mid sagittal T1-weighted MRI image through the sellar region. 1 = estimated diaphragm sella anteroposterior distance; 2 = anteroposterior distance of the infundibulum along the diaphragm sella; 3 = maximum anteroposterior distance of the sella; 4 = maximum cranio-caudal distance of the sella; 5 = cranio-caudal distance of the optic chiasm.

FIGURE 3

MRI showing protrusion of the optic disc (A), flattening of the posterior sclera (B), increased CSF perioptic space (C), and vertical tortuosity of the optic nerve (D).