DIAGNOSIS OF PSEUDOANEURYSM ON ENDOSCOPIC ULTRASOUND DOPPLER: THE "TO-AND-FRO" WAVEFORM

Introduction:
Visceral artery pseudoaneurysms include aneurysms of the celiac, superior, or inferior mesenteric arteries and their branches. Pseudoaneurysms have a high risk of rupture with life threatening consequences.

Case Presentation:
A 63-year-old male with a history of alcohol-related pancreatitis presented with obstructive jaundice. He was afebrile and hemodynamically stable on presentation. Physical exam noted scleral icterus, jaundice, and central excoriations. Labs were significant for hemoglobin 12.1 g/dL, total bilirubin 16.3 mg/dL, AST 152 U/L, ALT 131 U/L, ALP 591 U/L, and lipase 40 U/L. Computed tomography scan was significant for intra- and extra-hepatic ductal dilation, and a 3 cm cystic lesion in the head of pancreas. Endoscopic ultrasound (EUS) revealed a 30 x 30mm round lesion with turbulent swirling flow arising from the gastroduodenal artery and compressing the distal bile duct (Image 1). Doppler revealed an arterial “to-and-fro” waveform, consistent with a gastroduodenal artery pseudoaneurysm (Image 2). Endoscopic retrograde cholangiography revealed severe compression of the distal bile duct, and a covered metal stent was placed. The patient underwent angiography confirming a large gastroduodenal artery pseudoaneurysm, which was treated with vascular coils.

Discussion:
The “to-and-fro” waveform on Doppler is an important diagnostic clue to the presence of a pseudoaneurysm. The “to” represents the arterial blood going into the pseudoaneurysmal sac in systole, while “fro” illustrate blood exiting the sac in diastole. Recognition of this sign on EUS is important as pseudoaneurysms can be missed on cross-sectional imaging.