Objective: To evaluate 16-slice CT portography technique and appearances of cavernous transformation of portal vein (CTPV) and the correlation with surgical procedure of orthotopic liver transplantation (OLT).
Material and methods: Twenty-four patients with CTPV underwent triphase scanning using a 16-slice CT scanner. Twenty-one of the 24 patients were OLT candidates. After plain scan, enhanced CT scan was performed. The parameters were as follows: thickness of 2.5 mm, reconstruction interval of 1.3 mm, flow rate of 3-4 mL/s, contrast agent of 100 mL, delayed time of 20, 50, and 70 s, respectively. Imaging reformation, including MIP, VR, and SSD, were performed by one radiologist. Two radiologists assessed the thrombosis location and degree, collateral vessels, and superior mesenteric vein (SMV) or splenic vein (SV). The details of collateral vessels, thrombosis location were graded and recorded. One score was partial thrombosis of the main PV; 2 score, complete thrombosis of the main PV; 3 score, complete thrombosis of the main PV plus thrombosis of proximal SV or SMV, and the normal diameter of remaining veins; 4 score, complete thrombosis of the main PV plus thrombosis of more than a half of SV or SMV, and thin diameter of remaining veins; 5 score, complete nonvisualization of the main PV, one or both of SV and SMV, and thin diameter of remaining veins. Thirteen patients thereafter underwent OLT. Operation record was reviewed case by case.
Results: All cases obtained MIP images, 16 patients got VR images, and five cases had SSD images. These images can display thrombosis location, degree, and collateral vessels. All patients had hepatopetal collateral vessels. Eleven of the 21 OLT candidates had 1 score, two patients 2 score, four patients 3 score, one patient 4 score, and three patients had 5 score. Fourteen of the 21 candidates were performed end-to-end anastomosis between the donor's and recipient's portal veins, in which 11 patients had 1 score, two patients had 2 score, and two patients 3 score. Both patients with 3 score had normal SV; end-to-end anastomoses were performed between the donor portal vein and recipient SV. Two patients are waiting for donors. OLT was canceled or changed in the six patients with 4 score or 5 score. Correlation coefficient between the score of portal vein and surgical decision was 0.813 (P-value less than 0.001, nonparametric correlation).
Conclusions: Using 16-slice CT portography can noninvasively diagnose CTPV. The appearances of CTPV on the 16-slice CT portography can provide helpful information for surgeons to make an accurate preoperative decision. MIP is the optimal technique for displaying CTPV.