Visual Discrimination of Screen-detected Persistent from Transient Subsolid Nodules: an Observer Study

K. Chung, F. Ciompi, J. Scholten E. Th. Goo, M. Prokop, C. Jacobs, B. van Ginneken and C. Schaefer-Prokop

PLoS One 2018;13(2):e0191874.

DOI PMID Cited by ~4

PURPOSE: To evaluate whether, and to which extent, experienced radiologists are

able to visually correctly differentiate transient from persistent subsolid

nodules from a single CT examination alone and to determine CT morphological

features to make this differentiation.

MATERIALS AND METHODS: We selected 86 transient and 135 persistent subsolid

nodules from the National Lung Screening Trial (NLST) database. Four experienced

radiologists visually assessed a predefined list of morphological features and

gave a final judgment on a continuous scale (0-100). To assess observer

performance, area under the receiver operating characteristic (ROC) curve was

calculated. Statistical differences of morphological features between transient

and persistent lesions were calculated using Chi-square. Inter-observer agreement

of morphological features was evaluated by percentage agreement.

RESULTS: Forty-nine lesions were excluded by at least 2 observers, leaving 172

lesions for analysis. On average observers were able to differentiate transient

from persistent subsolid nodules >= 10 mm with an area under the curve of 0.75

(95% CI 0.67-0.82). Nodule type, lesion margin, presence of a well-defined

border, and pleural retraction showed significant differences between transient

and persistent lesions in two observers. Average pair-wise percentage agreement

for these features was 81%, 64%, 47% and 89% respectively. Agreement for other

morphological features varied from 53% to 95%.

CONCLUSION: The visual capacity of experienced radiologists to differentiate

persistent and transient subsolid nodules is moderate in subsolid nodules larger

than 10 mm. Performance of the visual assessment of CT morphology alone is not

sufficient to generally abandon a short-term follow-up for subsolid nodules.