The Venous Distension Sign: A Diagnostic Sign of Intracranial Hypotension at MR Imaging of the Brain
R.I. Farba,
R. Forghanib,
S.K. Leea,
D.J. Mikulisa and
R. Agida
a From the Department of Medical Imaging, Division of Neuroradiology, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
b Department of Medical Imaging, McGill University, Montreal, Quebec, Canada
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Fig 1. Normal contour of the transverse sinus. A, T1-weighted image through the approximated middle third of the dominant transverse sinus in a normal control. B, Magnified and cropped image of boxed area in A. C, Same image as B, with schematic representations of the inferior border of the transverse sinus drawn on the image. Both solid and dashed lines represent the normal variability in the contour of this lower border as demonstrated in individual normal controls D through K. The dotted line in C depicts the distended, convex, lower border of the middle third of the dominant transverse sinus (the VDS) as seen in intracranial hypotension (Fig 3).
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Fig 2. Typical MR findings in IH. A, Midline sagittal T1-weighted image showing the "sagging brain" appearance with distortion of the anterior margin of the pons and medulla (black arrows) and decreased vertical dimension of the suprasellar cistern and sagging tuber cinereum (dashed arrow), as well as the prominent pituitary gland (white arrow). B, Axial T2-weighted image showing effacement of the perimesencephalic cistern (dotted arrows), as well as the elongated anteroposterior dimension of the midbrain. C, Axial T2-weighted gradient echo (susceptibility weighted) image showing small bilateral subdural effusions (short arrows) with a small amount of hemosiderin staining (arrowheads), indicating previous subdural hemorrhage. D, Gadolinium-enhanced axial T1-weighted image demonstrating diffuse pachymeningeal (dural) enhancement (open arrows). E, T1-weighted image through the approximated middle third of the dominant transverse sinus (located by dashed line in B). F, Magnified image of boxed area in E showing the convex inferior margin of the transverse sinus (curved arrow), that is, the VDS indicative of IH.
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Fig 3. Examples of the VDS in 5 patients with IH pretreatment and posttreatment with EBP. A–E, Magnified and cropped sagittal T1-weighted images through the approximated middle third of the dominant transverse sinus of IHPs 1, 5, 11, 13, and 14 at presentation. A'–E', Corresponding image of each patient at follow-up MR imaging, after EBP and resolution of symptoms. Note the change in the contour of the transverse sinus (particularly the inferior border) between the before and after images of each patient (arrows).
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Fig 4. False-negative case. Sagittal T1-weighted image through the approximated middle third of the dominant transverse sinus magnified and cropped of IHP 10. This was interpreted as absent VDS by 2 of the 3 readers and was, therefore, registered as a false-negative result. Note the lower margin of the transverse sinus does appear straight (arrow).
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Fig 5. False-positive case. Sagittal T1-weighted image through the approximated middle third of the dominant transverse sinus magnified and cropped of CP 1. This was interpreted as a VDS by all 3 of the readers and, therefore, registered as a false-positive result. Note that the lower margin of the transverse sinus does appear slightly convex (arrow).
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