Lisette van Dam

Chapter 8 138 ( Figure 1A ). As prior MRI scans already showed increased signal intensities on fluid-attenuated inversion recovery (FLAIR) and restricted diffusion on diffusion weightedMR images at the same anatomical location, it was initially concluded that the lack of opacification of these sinuses on CT venography could well represent post-surgical changes or chronic thrombosis ( Figure 1B ). Even so, acute CVT could not be excluded with certainty and anticoagulant treatment was therefore started empirically. The next day, a MRI scan was performed including MR-NCTI sequences to evaluate these sinuses in more detail. MR-NCTI scan included three dimensional (3D) T1 weighted turbo field-echo (T1 TFE) and 3D Turbo Spin-echo Spectral Attenuated Inversion Recovery (TSE-SPAIR) sequences performed on a 3.0 Tesla unit ( Table 1 ). MRI venography confirmed the absence of flow in the posterior part of the superior sagittal sinus and in both transversal sinuses ( Figure 1C and D ), with concomitant (heterogenous) increased signal intensity on T2 weighted MR images. However, on MR-NCTI images no increased signal intensity was present at these locations, making the diagnosis of an (sub)acute CVT highly unlikely ( Figure 1E and F ). The final diagnosis therefore was changed into a cerebral sinus occlusion either due to chronic CVT or as a result of residual meningioma tissue. Anticoagulant treatment was discontinued, and she was discharged from hospital in good health. She was kept under outpatient surveillance at the department of Neurosurgery for regular follow-up after the meningioma resection. She had persistent headache which was diagnosed as tension type- and medication overuse headache. A 12-months follow-up MRI showed no new abnormalities and no new adverse events. DISCUSSION AND CONCLUSIONS The diagnosis of CVT is based on the positive findings of intraluminal thrombus on either CT or MRI, or a filling defect in a cerebral vein or sinus. 2,11 Excluding acute CVT with non-invasive conventional imaging techniques can be challenging. 2 MR- NCTI is a new technique based on the visualization of methemoglobin in a fresh thrombus which appears as a high signal intensity (bright signal). 12 This allows for the direct visualization of (sub)acute thrombi and the differentiation between acute and chronic thrombosis. 6,13,14 MR-NCTI has previously been shown to be accurate in the diagnosis of a first CVT and is likely to be valuable in the diagnostic management of complex cases in whomCT and MRI venography could not exclude