Postsurgical Intracranial Hypotension: Diagnostic and Prognostic Imaging Findings

Sagittal T1-weighted spin-echo (A) and coronal T2-weighted FSE images (B,C) after depth electrode placement for presurgical work-up. Sagittal (D), axial (E), and coronal (F) T2-weighted FSE images 5 days after left-sided hippocampectomy. Vasogenic edema with increased signal intensity on T2-weighted images and elevated ADC values on diffusion-weighted MR imaging (not shown) is present in the basal ganglia (E; open arrows) and, to a lesser extent, in the brain stem (D; open arrow). CSF loss causes noisy T2-weighted images (D-F) and sagging of the brain stem and cerebellum (D,F). Normally, the iter in the aqueduct is within 2 mm below the incisural line connecting the tuberculum sellae and the entrance of the vein of Galen into the straight sinus (A). With severe CSF loss, the iter and the splenium corporis callosi are displaced downwards (D). Note tonsillar displacement into the foramen magnum (arrows in F compared with B and C).

Axial FLAIR before right-sided temporal lobe lesionectomy (A,B), 1 day after the lesionectomy (C,D), and 5 years later (E,F). Note that sections in A, B, E, F are angulated along the temporal lobe length axis, whereas sections in C and D are angulated along the c.a.-c.p.-line. However, apart from the resection defect (C; thick arrow), moderate thalamic and basal ganglia hyperintensities (D; open arrow) and compressed ambient cisterns (C; arrows) are clearly visible. From a clinical standpoint, this 36-year-old woman had a complete recovery with resolution of the imaging findings (E,F).