Low-Tube-Voltage, Half-Dose Multidetector Liver CT with Sinogram-Affirmed Iterative Reconstruction (SAFIRE) Algorithm for Detection of Hypervascular Hepatocellular Carcinoma

Abstract

Introduction: The purpose of this study was to compare the image quality and lesion detectability of low-tube-voltage, half-dose liver CT reconstructed using sinogram–affirmed iterative reconstruction (SAFIRE) algorithm with full-dose scans using filtered back projection (FBP) algorithm for hypervascular hepatocellular carcinoma (HCC).

Methods: A total of 126 patients with suspected HCCs and who underwent liver CT including arterial phase scanning at 80-kVp in the dual-source mode (300-mAs for each tube), were included in this study. The half-dose arterial scans were reconstructed using FBP, iterative reconstruction in image space (IRIS), and five different SAFIRE strengths (S1-S5), respectively, and were compared with full-dose virtual scans (600-mA) reconstructed using FBP. I assessed the image noise, contrast-to-noise ratio (CNR) of the liver, vessels, and CNRlesion-to-liver . Two radiologists evaluated the image quality and lesion detectability on the different image sets.

Results: The image noise on SAFIRE images was significantly lower and the CNRs on SAFIRE images were higher than those on half-dose FBP images (p < 0.001). In addition, CNRlesion-to-liver on half-dose SAFIRE images with S5 was higher than on IRIS and full-dose FBP images (p < 0.05). Among the half-dose scans, SAFIRE images showed significantly better image quality than FBP images (p < 0.05). Regarding lesion detection, half-dose SAFIRE images were better than half-dose FBP images and were comparable with full-dose FBP images (91.8% vs. 96%, observer 1 and 98% vs. 98%, observer 2, p > 0.05).

Conclusions: Half-dose, 80-kVp liver CT using SAFIRE technique may increase the image quality and provide comparable lesion detectability of hypervascular HCC at a reduced radiation dose compared with full-dose CT with FBP.