CT OF THE DUODENOJEJUNAL JUNCTION

To determine the location of the duodenojejunal junction (DJJ) at comp uted tomography (CT), we retrospectively reviewed 309 consecutive CT e xaminations. These included 162 men and 127 women (mean age = 57 years old, range = 11-85 years old). Some people received more than one exa mination. The clinical indi cations included various kinds of neoplasm s, inflammations, congenital lesions, trauma, and other conditions. Th e DJJ was defined as the first sectioned ascending duodenum whose majo r part lies to the right side of the crossing part of the inferior mes enteric vein over the immediate beginning of the jejunum. Forty-nine e xaminations were excluded due to distortion of the DJJ by contiguous p athologic processes or nonadministration of intravenous contrast mediu m. In 36 examinations, the junctions were not identified. In the succe ssfully identified 224 examinations, the DJJ was located to the left i n 75 (33.5%), in the left half in 87 (38.8%), and in the right half or to the right of the vertebral body in 4 (1.8%) examinations. The midl ine of the DJJ was along the left margin and in the midline of the ver tebral body in 53 (23.7%) and 5 (2.2%) examinations. In the anteropost erior direction, it was totally in front of the aorta in 189 (84.4%) a nd within the projected contour of the aorta in 11 (4.9%) examinations . The midline of the DJJ was along the anterior margin of the aorta in 24 (10.7%) examinations. Its cephalocaudal position was at the upper L1 in 36 (16.1%), lower L1 in 70 (31.3%), upper L2 in 75 (33.5%), and lower L2 in 21 (9.4%) examinations even though it ranged from upper T1 2 to upper L3. In conclusion, CT offers another reliable method of loc alizing the duodenojejunal junction.