Liver lesions: improved detection with dual-detector-array CT and routine 2.5-mm thin collimation.

Abstract

To determine the feasibility and clinical benefit of routine performance of helical computed tomography (CT) with 2.5-mm collimation for the detection of liver lesions. Twenty patients with small (< or = 10-mm-diameter) liver lesions (total number of lesions, 167) were evaluated with a dual-detector-array CT scanner during the portal venous phase of contrast material enhancement. The acquisition was performed with 2.5-mm collimation during a single breath hold. The identical data set was used to perform reconstructions with 2.5-mm, 5.0-mm, 7.5-mm, and 10.0-mm section thicknesses with 50% section overlap. Each set of images was evaluated by three radiologists to determine lesion detection rates and conspicuity. Use of 2.5-mm-thick sections resulted in a 46% increase in detection rate versus use of 10.0-mm-thick sections (167 lesions vs 90 lesions), a 33% increase versus use of 7.5-mm-thick sections (167 vs 112), and an 18% increase versus use of 5-mm-thick sections (167 vs 137). Lesion conspicuity and radiologist confidence in lesion detection and characterization of lesion margins increased as section thickness decreased. CT of the liver can be performed routinely with 2.5-mm collimation with a dual-detector CT system, yielding greater conspicuity of small lesions and improved lesion detection.