Right anterior caudocranial oblique projection for portal venography; its indications and advantages

Right anterior caudocranial oblique (RACCO) projections were evaluated for transarterial portography with digital subtraction angiography. For RACCO projection, the image intensifier was tilted 25 degrees caudally and 30 degrees to the patient's right with the patient in the supine position. The abnormal findings imaged in 20 patients were analyzed by types of abnormalities and their locations in the portal venous systems by comparing RACCO and PA projections. The RACCO view was superior to the PA projection for demonstrating either encasements or tumor thrombi in relatively proximal segments of the portal venous branches. Two encasement lesions and a tumor thrombus were imaged only on the RACCO projection. However, the RACCO projection had no definite advantage over the PA view for showing encasements or tumor thrombi in the distal segmental branches. The RACCO projection was superior to the PA view for demonstrating defects in the hepatograms of some hepatic segments (S5 and S8). We concluded that the RACCO view is extremely useful and is indicated for angiographic work-ups of hepatic or biliary lesions when abnormalities are suspected in proximal portal venous branches.