Automated volumetry of solid pulmonary nodules in a phantom -: Accuracy across different CT scanner technologies

Objectives: The accuracy of automated volumetry for pulmonary nodules in a phantom using different CT scanner technologies from single-slice spiral CT (SSCT) to 64-slice multidetector-row CT (MDCT) was compared. Materials and Methods: A lung phantom with 5 different categories of pulmonary nodules was scanned using a single-slice spiral CT, a 4-slice MDCT, a 16-slice MDCT and a 64-slice MDCT. Each category comprised of 7-9 nodules each (total n = 40) with different known volumes. Standard dose and low dose protocols were performed using thin and thick collimation. Image data were reconstructed at the thinnest slice thickness. Data sets were analyzed with a dedicated volumetry software. Volumes of all nodules were calculated and compared. Results: Mean absolute percentage error (APE) for all nodules was 8.65% (+/- 7.29%) for the SSCT, 10.26% (+/- 8.25%) for the 4-slice MDCT, 8.19% (+/- 7.57%) for the 16-slice MDCT and 7.89% (+/- 7.39%) for the 64-slice MDCT. There was statistically significant influence of the scanner type, protocol, anatomic location, and nodule volume on APE, but overall, APEs were comparable. Conclusion: Computer-aided volumetry showed accurate measurements in all tested scanner types. This finding has important implications for nodule assessment and follow-up.