Detection of Hepatocellular Carcinomas on Dynamic Phase Images Using Multi-detector CT: Comparison with Different Slice Thickness and Image Output

To compare the diagnostic performance of a high-resolution picture archiving and communications system(PACS) workstation directly interfaced with computed tomography(CT) with hard-copy printouts and to compare the detection rate according to slice thickness in hepatocellular carcinomas(HCCs).

Forty-six patients with 118HCCs underwent two-phase multi-detector row helical CT imaging of the entire liver after contrast administration. Late arterial phase images were obtained serially during a single breast-hold, and portal venous-phase images were then obtained. In soft-copy, images taken in each phase were reconstructed by 3mm and 7mm in thickness. Soft-copy readouts on a workstation in PACS and hard-copy printouts were independently compared for the presence of HCC by two radiologists unaware of the possible presence of tumors, and for each phase the detection rate was determined in 7mm thickness. The detection rate of HCC displayed on a workstation was analyzed in 3mm and 7mm thickness for each phase.

No significant differences in observer performance were observed between laserprinted hard copies and CT images displayed on a workstation(p>0.05). But the detection rate of HCC displayed on workstation was higher in 3mm thickness(p<0.05).

The diagnostic performance of CT hard copies is acceptable and comparable to a high-resolution PACS workstation in hepatocellular carcinomas and the detection rate of HCC on PACS workstation is significantly higher in thin slice thickness.