Lisette van Dam

MRDTI in abdominal aortic thrombosis 9 149 to assess the age of the thrombus, which showed a low signal intensity of the aortic thrombus indicative of chronic rather than acute thrombosis ( Figure 1C ). A high signal intensity was only found in the aortic wall at the level of the left renal artery where the PTA had caused acute occlusion and bypass surgery had been performed ( Figure 1D ). Because no acute thrombosis was identified, anticoagulant treatment was not started, and antiplatelet therapy continued. Abdominal ultrasonography after the bypass surgery showed open bypasses. The renal function gradually improved, and the patient could be discharged from hospital in good health. Genetic testing was performed because of the premature aortic thrombosis in presence of an AAA but was negative for connective tissue disorders or chromosomal syndromic thoracic aortic aneurysm. The patient was kept under close outpatient surveillance because of chronic persistent renal insufficiency with an eGFR of 60mL/min. In the first year after presentation, there were no thrombotic or bleeding complications. DISCUSSION Aortic ILT may lead to peripheral embolism resulting in occlusion of the distal arteries. 3 Importantly, an acute aortic thrombosis (AAT) is a rare life-threatening event and may be caused by in-situ thrombosis of an atherosclerotic aorta, large saddle embolus to the aortic bifurcation or occlusion of previous surgical reconstruction. 4 Prompt management is indicated in case of an AAT or an acute ischemic event caused by distal embolization 4 and may be considered in an unstable thrombus. 1 However, current imaging modalities do not allow for accurate distinction between acute versus chronic thrombosis. It is therefore challenging to differentiate between stable and unstable thrombi. MRDTI is a technique in which a thrombus can directly be visualized without the use of a potential toxic contrast agent. This method is based on the formation of methemoglobin in a fresh thrombus leading to shortening of the T1 signal on MRI. 5 It has been shown to accurately diagnose a first deep vein thrombosis (DVT) and distinguish chronic thrombotic remains from acute recurrent DVT with a sensitivity of 95-100% and specificity of 100%. 6,7 Current studies are evaluating its diagnostic accuracy for unusual site venous thromboembolism, including upper extremity DVT and splanchnic vein thrombosis (NTR 5738 and NTR 7061), where current imaging tests often cannot provide a definite diagnosis.