Lung cancer screening with ultra-low dose CT using full iterative reconstruction

Jpn J Radiol. 2017 Apr;35(4):179-189. doi: 10.1007/s11604-017-0618-y. Epub 2017 Feb 14.


Purpose: To investigate the diagnostic capability of ultra-low-dose CT (ULDCT) with full iterative reconstruction (f-IR) for lung cancer screening.

Materials and methods: All underwent ULDCT and/or low-dose CT (LD-CT) on a 320-detector scanner. ULDCT images were reconstructed with f-IR. We qualitatively and quantitatively studied 95 nodules in 69 subjects. Two radiologists classified the nodules on ULDCT images as solid-, part-solid-, and pure ground-glass (PGG) and recorded their mean size. Their findings were compared with the reference standard. The observer performance study included 7 other radiologists and 35 subjects with- and 15 without nodules. The results were analyzed by AFROC analysis.

Results: In the qualitative study, the kappa values between observers 1 and 2, respectively, and the reference standard were 0.70 and 0.83; the intra-class correlation coefficients for the nodule diameter between the reference standard and their measurements were 0.84 and 0.90. The 95% confidence interval (CI) for the area under the curve (AUC) difference for nodule detection on LDCT and ULDCT was -0.03 to 0.07. The 95% CI crossed the 0 difference in the AUC but not the pre-defined non-inferiority margin of -0.08.

Conclusion: The diagnostic ability of ULDCT using f-IR is comparable to LDCT.

Keywords: Low-dose CT; Lung cancer CT screening; Ultra-low-dose CT.

MeSH terms

  • Aged
  • Early Detection of Cancer / methods
  • Female
  • Humans
  • Lung Neoplasms / diagnostic imaging*
  • Male
  • Middle Aged
  • Radiation Dosage
  • Radiographic Image Interpretation, Computer-Assisted / methods
  • Tomography, X-Ray Computed / methods