Excessive z-axis scan coverage in body CT: frequency and causes

Yar O., ONUR M. R., İDİLMAN İ. S., AKPINAR E., AKATA D.

EUROPEAN RADIOLOGY, vol.31, no.6, pp.4358-4366, 2021 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 31 Issue: 6
  • Publication Date: 2021
  • Doi Number: 10.1007/s00330-020-07510-4
  • Journal Name: EUROPEAN RADIOLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Agricultural & Environmental Science Database, Biotechnology Research Abstracts, CINAHL, EMBASE, MEDLINE
  • Page Numbers: pp.4358-4366
  • Keywords: Diaphragm, Thorax, Tomography, X-ray computed, Lung, Radiation, ionizing, CHEST CT, RADIATION-EXPOSURE
  • Hacettepe University Affiliated: Yes

Abstract

Objectives The aim of this study was to determine the frequency and causing factors of excessive z-axis coverage in body CT examinations. Methods A total of 2032 body CT examinations performed between 1 March and 1 April 2018 in 1531 patients were included in this study. The over-scanned length values in the z-axis for each CT examination on each patient were determined by calculating the difference between the actual scanned length and optimal scan length in the z-axis. Over-scanning and over-scanning ratios were interrogated in terms of potential underlying factors that can be affected by patient demography, time, the throughput of CT, and the experience of technologists. Results Over-scanned CTs in z-axis were 66% of all CTs performed. CT scans were over-scanned in the cranial side in 18.4% and caudal side in 48.5% of patients. Over-scanning was found to be more frequent in 55-64-year-old age group (74%), thorax CTs (89.2%), patients with consciousness change (88.9%), patients with misleading findings related to lung apex or diaphragm on the scout images (76.6%), CTs performed in day shift (66.8 %), in CT with low daily scan (72.4%), and CT scans performed by less-experienced technologists (75.9%). Conclusions Over-scanning in z-axis in body CT examinations is not infrequently encountered in routine practice. Awareness of causes of over-scanning in z-axis can be helpful to prevent over-scanning in CT and unnecessary ionizing radiation exposure in patients.