Partially Recanalized Chronic Dural Sinus Thrombosis: Findings on MR Imaging, Time-of-Flight MR Venography, and Contrast-Enhanced MR Venography
J.L. Leachb,
M. Wolujewicza and
W.M. Struba
a Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
b The Neuroscience Institute, Cincinnati, Ohio
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Fig 1. Partially recanalized thrombosis of the left sigmoid sinus: 47-year-old man with 45-day history of headache (patient 3). Shown are an axial FSE T2-weighted image (T2WI) (A), an axial SE T1-weighted image (T1WI) (B), an axial SE T1WI after contrast (C), a source image from axially acquired TOF-MRV (D), an axial reformatted source image from CE-MRV (E), and a lateral projection volume rendered image from CE-MRV (F). The signal intensity of the thrombus was heterogeneous and primarily hyperintense relative to gray matter on T2WI (arrowhead, A), and isointense on T1WI (arrow, B). Flow voids were identified on parenchymal sequences (arrows in A–C) that correspond to recanalized channels on MRV techniques (arrows in D and E). Areas of thrombus were seen as regions of signal intensity void on the MRV images (arrowheads, D and E). Note that the channels are slightly larger and more ill-defined on CE-MRV (arrows, E). The thrombus enhances intensely after contrast administration (arrowhead, C). The recanalized channels are well seen on CE-MRV volume-rendered images (arrows, F). Filling defects consistent with thrombus are identified in among the recanalized channels (arrowheads, F).
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Fig 2. Evolution of acute thrombosis: 43-year-old woman (patient 4) presented for imaging 2 days after onset of severe headache (A–C). Shown are follow-up imaging 197 days later (D–F), axial FSE T2-weighted images (A and D), axial SE T1-weighted images after contrast (B and E), and source images from axially acquired TOF-MRV. On the initial MR (C and F), acute thrombus was identified within the distal transverse and proximal sigmoid sinus. The thrombus was hypointense on T2-weighting (arrows, A) and isointense on T1-weighted images, without enhancement (arrows, B). The thrombosed portions of the sinus exhibited no flow-related signal intensity on TOF-MRV (arrows, C). Some minimal flow signal intensity was seen surrounding the thrombus (arrowhead, C), likely related to collateral flow within dural cavernous spaces or peripherally within the sinus. On the follow-up examination, a central flow void had formed on T2WI and postcontrast T1WI consistent with a recanalized channel (arrows, D and E). Peripheral heterogeneous isointense to hyperintense signal intensity is seen (arrowheads, D), enhancing on postcontrast T1-weighting (arrowheads, E), without flow-related signal intensity on TOF-MRV (arrowheads, F), consistent with enhancing chronic thrombus. The central channel exhibits marked flow-related signal intensity on TOF-MRV (arrow, F).
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Fig 3. Partially recanalized thrombosis of the left transverse and sigmoid sinuses (patient 6). Shown are a TOF-MRV oblique MIP (A), a CE-MRV oblique MIP (B), a local oblique volume rendered CE-MRV image (C), and an axial reformatted source image from CE-MRV (D). No flow signal intensity was identified on TOF-MRV within the thrombosed left transverse and sigmoid sinuses (A). There was normal flow-related signal intensity in the right transverse and sigmoid sinuses (arrowheads, A). The morphology of the partially recanalized sinuses is better depicted on CE-MRV (B). Small irregular recanalized channels were seen within the left transverse sinus (small arrows, B). The sigmoid sinus opacifies more completely; however, focal and linear irregular filling defects are visualized (arrowheads, B). The left transverse and sigmoid sinuses enhance less prominently than the normal right transverse and sigmoid sinuses (large arrows, B). The small irregular recanalized channels are even better depicted on a detailed volume-rendered representation (arrows, C). Reformatted axial images from the CE-MRV demonstrate internal filling defects within the left transverse sinus, consistent with hypoenhancing thrombus (arrows, D).
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