Lisette van Dam

Detection of UEDVT by MR-NCTI 5 79 INTRODUCTION Upper extremity deep vein thrombosis (UEDVT) is an uncommon presentation of venous thromboembolism (VTE), accounting for approximately 5-10% of all thromboses in the deep veins. 1,2 As in lower extremity deep vein thrombosis (DVT), the first line imaging test is compression ultrasonography (CUS). 3 Diagnosing UEDVT with ultrasonography is more complex than in the lower extremities due to the local anatomy, especially in the axillary and clavicular areas where veins may be difficult to visualize and compress. Therefore, CUS is commonly used in combination with doppler ultrasonography to diagnose or exclude UEDVT. Contrast-venography is the diagnostic standard for UEDVT, but it is an invasive imaging test where patients are exposed to intravenous contrast and radiation. Furthermore, as venography is not routinely performed anymore, radiologists have limited experience evaluating UEDVT by this method. 4,5 Computed tomography (CT) venography is often used as an alternative, although studies regarding its diagnostic accuracy in UEDVT are scarce. 6 Moreover, CT venography may be less applicable in patients with severe chronic kidney disease (e.g. stage 4) given the need for intravenous contrast dye. The validation of an alternative, non-invasive imaging technique would therefore satisfy an unmet clinical need. Magnetic Resonance Non-Contrast Thrombus Imaging (MR-NCTI) is an imaging technique that may have the potential to replace venography as second-line diagnostic test in case of inconclusive CUS. MR-NCTI is a non-contrast-enhanced magnetic resonance (MR) technique used to directly visualize acute thrombi utilizing the formation of methemoglobin in a fresh thrombus, which appears as a high signal intensity. 7,8 Magnetic Resonance Direct Thrombus Imaging (MRDTI) is a T1-weighted MR-NCTI sequence that previously has been shown to be an accurate and reproducible diagnostic test in patients with suspected first and recurrent ipsilateral DVT. 9-11 Moreover, MR-NCTI has shown to be useful in other locations where the diagnosis of thrombosis can be difficult, including isolated pelvic vein thrombosis in pregnant patients and portal vein thrombosis. 12,13 Three Dimensional Turbo Spin-echo Spectral Attenuated Inversion Recovery (3D TSE- SPAIR) is another T1-weighted MR-NCTI sequence that could be useful in the diagnostic management of UEDVT. Both MRDTI and 3D TSE-SPAIR were found feasible for the diagnosis of UEDVT in a recent small pilot study. 14 We aimed to more accurately determine the diagnostic accuracy of MR-NCTI, combining MRDTI and 3D TSE-SPAIR for the diagnosis of UEDVT.