Added Value of Integrated Circuit Detector in Head CT: Objective and Subjective Image Quality in Comparison to Conventional Detector Design

Abstract

A new computed tomography (CT) detector with integrated electric components and shorter conducting pathways has recently been introduced to decrease system inherent electronic noise. The purpose of this study was to assess the potential benefit of such integrated circuit detector (ICD) in head CT by comparing objective and subjective image quality in low-dose examinations with a conventional detector design. Using a conventional detector, reduced-dose noncontrast head CT (255mAs; effective dose, 1.7mSv) was performed in 25 consecutive patients. Following transition to ICD, 25 consecutive patients were scanned using identical imaging parameters. Images in both groups were reconstructed with iterative reconstruction (IR) and filtered back projection (FBP) and assessed in terms of quantitative and qualitative image quality. Acquisition of head CT using ICD increased signal-to-noise ratio of gray and white matter by 14% (10.0±1.6 vs. 11.4±2.5; P=.02) and 17% (8.2±0.8 vs. 9.6±1.5; P=.000). The associated improvement in contrast-to-noise ratio was 12% (2.0±0.5 vs. 2.2±0.6; P=.121). In addition, there was a 51% increase in objective image sharpness (582±85 vs. 884.5±191; change in HU/Pixel; P<.000). Compared to standard acquisitions, subjective grading of noise and overall image quality scores were significantly improved with ICD (2.1±0.3 vs. 1.6±0.3; P<.000; 2.0±0.5 vs. 1.6±0.3; P=.001). Moreover, streak artifacts in the posterior fossa were substantially reduced (2.3±0.7 vs. 1.7±0.5; P=.004). At the same radiation level, acquisition of head CT with ICD achieves superior objective and subjective image quality and provides potential for significant dose reduction.