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

PURPOSE: 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. MATERIALS AND METHODS: Twenty patients with small (less than or equal to 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-min collimation during a single breath hold. The identical dataset 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. RESULTS: 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. CONCLUSION: 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.