CT-angiography with a 16-row CT scanner for perioperative evaluation of the hepatic arteries

Purpose: To evaluate the efficiency of CT angiography (CTA) with 16-row MSCT compared with MR angiography (MRA) in analyzing the arterial anatomy in patients undergoing liver surgery. Materials and Methods: In 30 patients, MRA and CTA studies of the abdominal vessels were reviewed. CT parameters: slice thickness 3 mm: collimation 1.5; reconstruction interval 2 mm (Philips MX 8000 IDT); 120 ml contrast media (400 mg/ml) at a rate of 4 ml/sec; acquisition of arterial-phase scans. The anatomy of the hepatic artery was evaluated from axial and reconstructed maximum-intensity-projection (MIP) images ("Slab-Viewer", Philips). MR parameters: contrast-enhanced coronal FLASH-3D sequences; slice thickness 1.4 mm; TR 3.47, TE 1.3; 1.5 T scanner (Siemens Somatom). Image quality was rated with a scoring system. Contrast enhancement of the hepatic artery and the liver parenchyma was measured. Results: The image quality of CTA was rated as excellent in 18 (MRA 5); good in 8 (MRA 22); satisfactory in 4 patients (MRA 3), and non-diagnostic in 0 patient (MRA 1). Compared to MRA, the image quality of CIA was better in 15/30 patients; equal for both in 13 and worse in 2 patients. CTA provided a better depiction of the segmental branches of the hepatic arteries in 15/30 patients and revealed important anatomic variations of the hepatic artery in 8/30 patients. These variations were not be seen in MRA: e. g., MRA missed a left gastric arterial supply to the left liver. The ratio of contrast enhancement in liver parenchyma and hepatic artery was 4.7 in CTA and 4.5 in MRA. Conclusion: CTA with multislice scanners delivers better image quality and depiction of the hepatic arteries than MRA. Thus, MRI of the hepatic arteries can be replaced by routine CT, which is already part of the preoperative evaluation for liver transplantation.