Volumetry versus linear diameter lung nodule measurement: an ultra-low-dose computed tomography lung cancer screening study

Abstract

BACKGROUND:The Dutch–Belgian Randomized Lung Cancer Screening Trial (NELSON) used a volume-based protocol and significantly reduced the prevalence of false-positive results (2.1%).AIM: To compare the performance of manual linear diameter and semi-automated volumetric nodule measurement in the pilot project “Moscow Lung Cancer Screening” ultra-low-dose computed tomography pilot study.MATERIALS  AND  METHODS:  The  study  included  individuals  with  a  lung  nodule  of  at  least  4  mm  on  baseline-computed  tomography  of  the  Moscow  lung  cancer  screening  between  February  2017  and  February  2018,  without  verified  lung  cancer  diagnosis until 2020. The radiation dose was selected individually and did not exceed 1 mSv. All scans were assessed by three blinded readers to measure the maximum and minimum transversal nodule diameter and extrapolated volume. As a reference value of size and volume, the average value from the results of expert measurements was obtained. A false-positive nodule was defined as a nodule <6 mm/<100 mm3 and a false-negative nodule as a nodule ≥6 mm/≥100 mm3.RESULTS: Overall, 293 patients were included (166 men; mean age, 64.6 ± 5.3years); 199 lung nodules were <6 mm/<100 mm3and 94 were ≥6 mm/≥100 mm3. Regarding volumetric measurements, 32 [10.9%; 4 false-positive, 28 false-negative], 29 [9.9%; 17 false-positive, 12 false-negative], and 30 [10.2%; 6 false-positive, 24 false-negative] nodule discrepancies were reported by  readers  1,  2,  and  3  respectively.  For  linear  diameter  measurement,  92  [65.5%;  107  false-positive,  85  false-negative],  146 [49.8%; 58 false-positive, 88 false-negative], and 102 [34.8%; 23 false-positive, 79 false-negative] nodule discrepancies were reported by readers 1, 2, and 3 respectively.CONCLUSIONS: Theuse of lung nodule volumetry strongly reduces the number of false-positive and false-negative nodules compared with nodule diameter measurements, in an ultra-low-dose computed tomography lung cancer screening program.