Anatomic variations of the hepatic arteries in 250 patients studied with 64-row CT angiography.

The aim of our study was to determine the frequency of different hepatic arterial variants identified on abdominal CT angiography (CTA) with a 64-row CT system and a high resolution protocol. A total of 250 consecutive abdominal CTAs performed on a 64-row CT system were evaluated. Two radiologists in consensus analyzed arterial phase images; the anatomical findings were grouped according to Michels' classification. An anomalous arterial pattern was observed in 34% of the cases. The most common anomaly was Michels type III (9.2%), followed by types II and V (5.2%), type VI (4.0%), types IV, VII, and IX (2.0%), and type VIII (0.6%). No cases of type X were detected. Unclassified variations were observed in 3.3% of the cases. The new generation of 64-row MDCT allows optimal visualization of splanchnic vascular anomalies with a minimally invasive examination. This visualization is extended to those vessels with a small caliber and slow flow resulting in difficult recognition by classic angiographic studies. The knowledge of anomalous arterial patterns could be very useful in the preoperative planning of surgical and interventional liver procedures.