Iterative CT reconstruction in abdominal low-dose CT used for hybrid SPECT-CT applications: effect on image quality, image noise, detectability, and reader's confidence.

ABSTRACT: Background:Iterative computed tomography (CT) image reconstruction shows high potential for the preservation of image quality in diagnostic CT while reducing patients' exposure; it has become available for low-dose CT (LD-CT) in high-end hybrid imaging systems (e.g. single-photon emission computed tomography [SPECT]-CT). Purpose:To examine the effect of an iterative CT reconstruction algorithm on image quality, image noise, detectability, and the reader's confidence for LD-CT data by a subjective assessment. Material and Methods:The LD-CT data were validated for 40 patients examined by an abdominal hybrid SPECT-CT (U?=?120 kV, I?=?40 mA, pitch?=?1.375). LD-CT was reconstructed using either filtered back projection (FBP) or an iterative image reconstruction algorithm (Adaptive Statistical Iterative Reconstruction [ASIR]®) with different parameters (ASIR levels 50% and 100%). The data were validated by two independent blinded readers using a scoring system for image quality, image noise, detectability, and reader confidence, for a predefined set of 16 anatomic substructures. Results:The image quality was significantly improved by iterative reconstruction of the LD-CT data compared with FBP (P???0.0001). While detectability increased in only 2/16 structures (P???0.03), the reader's confidence increased significantly due to iterative reconstruction (P???0.002). Meanwhile, at the ASIR level of 100%, the detectability in bone structure was highly reduced (P?=?0.003). Conclusion:An ASIR level of 50% represents a good compromise in abdominal LD-CT image reconstruction. The specific ASIR level improved image quality (reduced image noise) and reader confidence, while preserving detectability of bone structure.

SUBMITTER: Grosser OS 

PROVIDER: S-EPMC6587393 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature