Lisette van Dam

Chapter 7 124 Magnetic resonance black-blood thrombus imaging Recently, magnetic resonance black-blood thrombus imaging (MRBTI), a native contrast thrombus MR technique, has been evaluated in the setting of suspected CVT. 14,86,87 MRBTI yielded a sensitivity of 100% and specificity of 96%, even up to the level of individual venous segments, using CT and MRI in combination with clinical and outcome assessments -but not DSA- as diagnostic standard. 86 A very similar native contrast thrombus MR technique, MR Direct Thrombus Imaging (MRDTI), has been shown to be highly accurate for the diagnosis of deep vein thrombosis and for the differentiation of acute versus chronic deep vein thrombosis in the legs. 88-93 Thus, this technique may be of great value for diagnosing CVT as well, especially in complex cases such as in suspected recurrent CVT. Further research is however needed before MRBTI can be used for the diagnosis of CVT in daily clinical practice. MRI versus CT venography When CT venography was compared to MRI, CT venography had a sensitivity of 100% and specificity of 100% for the diagnosis of cerebral sinus thrombosis ( Appendix 6 ). 42,94,95 Two of these studies even found that CT venography was better for the evaluation of small vessel anatomy with fewer artefacts than MRI. 42,94 It is important to note that these studies were small (n=24-36), included patients with suspected CVT but also patients without the suspicion for CVT (follow-up after acute CVT or pre-operative screening), and did not perform the same MR sequences in all included patients. CONCLUSION Contrast-enhanced MRI is more accurate than non-contrast-enhanced MRI for diagnosing CVT, as CT venography is more accurate than CT. Both CT venography and contrast-enhanced MRI seem adequate for establishing a CVT diagnosis. Solid evidence to choose one over the other is however unavailable. In practice therefore, clinical availability, local preference and experience mainly determine which modality is used. Large high-quality diagnostic studies are needed to improve clinical care and standardize clinical trials.