Abstract
We investigated the usefulness of contrast-enhanced ultrasonography(CEUS) in the diagnosis of autoimmune pancreatitis(AIP). We examined 7 AIP patients (5 males and 2 females) with an average age of 67 years (range: 57-74 years). Ultrasonic diagnostic equipment used consisted of a Toshiba SSA-370A (PowerVision 6000) and an SSA-770A (Aplio). A galactose/palmitic acid mixture (Levovist®) was employed as the contrast agent. The contrast enhancement effect was investigated by advanced dynamic flow(ADF) -flash echo imaging(FEI). 1) Enlargement of the pancreas was seen in all patients. Affected regions of the pancreas included the entire pancreas (3 patients), head of the pancreas (3 patients; 2 of whom had already undergone caudal resection), and body of the pancreas (1 patient). Internal echo images showed low-echo regions. One patient with an enlarged tail of the pancreas showed a low echo region similar to the circle in the head of the pancreas. 2) Contrast-enhancement patterns were classified into two types: Type I (5 patients) showed uniform contrast enhancement, and Type II (2 patients) showed non-contrast enhancement. 3) The degree of enlargement of the pancreas was reduced post-therapy in all patients. 4) In 4 of the 5 Type I patients, contrast enhancement was attenuated post-therapy, and 1 patient showed continued contrast enhancement. All Type II patients showed non-contrast enhancement both pre- and post-therapy. Type II CEUS patterns allowed classification of AIP. The possibility of being able to make an effective judgment for treatment was suggested in the case of a Type I pattern. Differential diagnosis and the effects from treatment were difficult to determine in patients with Type II patterns. Therefore it was thought necessary to perform an endoscopic retrograde cholangiopancreatography(ERCP) along with a self-immunological search to acquire additional diagnostic information.
