Compression of the Main Pancreatic Duct by the Intrapancreatic-Replaced Common Hepatic Artery
A 63-year-old male was admitted to the hospital for an elevation of hepatic enzymes and dark colored urine. He had experienced fatigue and malaise. He had no abdominal pain and neither significant medical history nor family history. Based on the viral maker assay, he was diagnosed with acute hepatitis and possible hepatitis A infection. On routine abdominal ultrasonography to rule out other organic causes, main pancreatic duct dilatation was incidentally found. The patient underwent contrast enhancement liver dynamic CT and MRCP for further characterization of duct dilatation and evaluation of liver. Contrast enhancement CT scan was taken by bolus tracking method. Liver dynamic CT consisting of four phase (unenhanced, arterial [15 seconds], portal [40 seconds] and delayed [3 minutes] scan) images were acquired with an 16-channel multi-detector raw CT (Mx8000 IDT 16 CT scanner; Philips Medical System, Best, The Netherlands). In addition, MRCP images were acquired with a 3.0 Tesla MR scanner (Achieva 3.0T X-series, Philips Medical System, Best, The Netherlands). On axial and coronal curved multiplanar reconstruction images using arterial phase scan, the CHA was arising from the superior mesenteric artery (SMA) and traveling through the pancreatic head parenchyma and across the main pancreatic duct, supero-posteriorly (). The upstream main pancreatic duct crossing the replaced CHA shows diffuse tubular dilatation without abnormal wall thickening or enhancement. Endoscopic retrograde cholangiopancreatography (ERCP) shows abrupt transverse filling defect at pancreas head and stasis of the contrast medium during the ERCP procedure (). Routine MRCP images revealed a compression of main pancreatic duct by the replaced CHA seen as a tubular signal void appearing as dark signal intensity at the corresponding area of the ERCP, which is flow void on the CHA, on both coronal T2 weighted image (repetition time [TR]/echo time [TE], 1728/80; section thickness 3 mm) and maximum intensity projection of respiratory triggered 3-dimensional turbo spin-echo MRCP images (TR/TE, 1868/600) (). The main pancreatic duct was compressed and dilated by the intrapancreatic-replaced CHA, resulted in prolonged stasis of the contrast medium in the upstream pancreatic duct noted on ERCP. However, this patient was asymptomatic and gave no evidence of history suggesting acute pancreatitis. This finding posed a dilemma to the clinician and surgeon because the prolonged stasis of contrast medium in the dilated pancreatic duct is a potential cause of acute pancreatitis. However, the clinician and surgeon decided upon close observation of patient status instead of the distal pancreatectomy because the high morbidity and mortality of surgical treatment was not beneficial to an asymptomatic patient.