Prevalence and Severity of Off-Centering During Diagnostic CT: Observations From 57,621 CT scans of the Chest, Abdomen, and/or Pelvis

Oladunni O. Akin-Akintayo, Lauren F. Alexander, Rebecca Neill, Elizabeth A. Krupinksi, Xiangyang Tang, Pardeep Kumar Mittal, William C. Small, Courtney C. Moreno

Research output: Contribution to journalArticle

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Purpose: To determine distances between patient centroid and gantry isocenter during CT imaging of the chest, abdomen, and/or pelvis, and to evaluate differences based on patient gender, scan region, patient position, and gantry aperture. Materials and Methods: A water phantom and an anthropomorphic phantom were imaged in the centered position in the CT gantry and at several off-centered positions. Additionally, data from 57,621 adult chest, abdomen, and/or pelvic CT acquisitions were evaluated. Data were analyzed with an analysis of variance using the centroid-to-isocenter data as the dependent variable and the other parameters as independent variables. Results: The majority of patient acquisitions (83.7% (48271/57621)) were performed with the patient's centroid positioned below isocenter (mean 1.7 cm below isocenter (SD 1.8 cm); range 12.1 cm below to 7.8 cm above isocenter). Off-centering in the x-axis was less severe (mean 0.01 cm left of isocenter (SD 1.6 cm)). Distance between centroid and isocenter in the y-axis did not differ as a function of sex but did differ based on scan region, patient position, and gantry aperture. Conclusion: Off-centering is common during CT imaging and has been previously demonstrated to impact dose and image quality.

Original languageEnglish (US)
Pages (from-to)229-234
Number of pages6
JournalCurrent Problems in Diagnostic Radiology
Issue number3
Publication statusPublished - May 1 2019


ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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