Abstract
Background and Purpose-Transverse sinus thrombosis can have nonspecific clinical and radiographic signs. We hypothesized that the novel "sigmoid notch sign" (on head CT) can help differentiate transverse sinus thrombosis from a congenitally atretic sinus among individuals with absent signal in 1 transverse sinus by MR venography. Methods-We retrospectively evaluated 53 subjects with a unilaterally absent transverse sinus signal on MR venography. Eleven had true transverse sinus thrombosis and 42 had an atretic transverse sinus. Reviewers were trained in the sigmoid notch sign: "positive" if 1 of the sigmoid notches was asymmetrically smaller than the other, consistent with a congenitally absent transverse sinus on that side. This sign was scored on CT scans by 2 blinded reviewers to determine if signal dropout was clot or atretic sinus. A consensus rating was reached when the reviewers disagreed. Characteristics of the sigmoid notch sign as a diagnostic test were compared with a gold standard of full chart review by an independent reviewer. Results-Each reviewer had a sensitivity of 91% (detecting 10 of 11 clots based on a negative sigmoid notch sign) and specificity of 71% to 81%; consensus specificity increased to 86% (36 of 42 individuals with an atretic sinus had a positive notch sign, detecting atretic sinuses based on presence of the sign). Conclusion-Asymmetries of the sigmoid notches on noncontrast brain CT is a very sensitive and specific measure of differentiating transverse sinus thrombosis from an atretic transverse sinus when absence of transverse sinus flow is visualized on MR venography.
Original language | English (US) |
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Pages (from-to) | 1968-1970 |
Number of pages | 3 |
Journal | Stroke |
Volume | 43 |
Issue number | 7 |
DOIs | |
State | Published - Jul 2012 |
Keywords
- sigmoid notch sign
- transverse sinus
- venous sinus atresia
- venous sinus occlusion
ASJC Scopus subject areas
- Clinical Neurology
- Cardiology and Cardiovascular Medicine
- Advanced and Specialized Nursing