Use of Volumetry for Lung Nodule Management: Theory and Practice

Abstract

A consistent feature of many lung nodule management guidelines is the recommendation to evaluate nodule size by using diameter measurements and electronic calipers. Traditionally, the use of nodule volumetry applications has primarily been reserved for certain lung cancer screening trials rather than clinical practice. However, even before the first nodule management guidelines were published more than a decade ago, research has been ongoing into the use of nodule volumetry as a means of measuring nodule size, and this research has accelerated in recent years. This article aims to provide radiologists with an up-to-date review of the most recent literature on volumetry and volume doubling times in lung nodule management, outlining their benefits and drawbacks. A brief technical review of typical volumetry applications is also provided. RSNA, 2017.

Automated delineation of non‐small cell lung cancer: A step toward quantitative reasoning in medical decision science

“…Firstly, for masses with reduced attenuation, which are normally known as sub‐solid masses, under‐segmentation or false negatives may be observed, particularly for GGO masses. Earlier studies have described high errors of volumetric segmentation in sub‐solid nodules in comparison to solid nodules . For example, subject 054 (Figure , first column) and subject 224 (Figure , first column) consist of reduced attenuation characteristics and both suffered the issue.…”

“…Earlier studies have described high errors of volumetric segmentation in sub-solid nodules in comparison to solid nodules. 25,26 For example, subject 054 ( Figure 7A, first column) and subject 224 ( Figure 7B, first column) consist of reduced attenuation characteristics and both suffered the issue. Additionally, under-segmentation was also observed in one experimental case involving a mediastinal mass ( Figure 4B, first column), which was assumed to be a unique event involving the "bridging" condition.…”

“…In this study, however, we focus more on solid NSCLC, even though some cases of reduced attenuation like cavitation are still evaluated. Other types of reduced attenuation such as ground glass opacity (GGO) and reticulation are particularly avoided, since earlier studies demonstrated high errors of computer‐assisted segmentation when evaluating sub‐solid nodules, especially the GGO case . The gold standard for these cases would be manual delineations by an expert radiologist, though we do believe a sophisticated algorithm like deep learning which has recently gained tremendous interest from the medical imaging community, could provide a solution.…”

2D or 3D measurements of pulmonary nodules: preliminary answers and more open questions

“…Nodule size is most commonly measured manually using electronical calipers, with the long-and perpendicular short-axis being measured on two-dimensional images (5). As a management criterion alternative to size, three-dimensional nodule volume has been discussed in the literature (6) and has also received mention in recent management guidelines for incidental nodules (1,3).…”

“…This causes another relevant problem, as many patients to undergo consecutive examinations on different CT scanner models operating with constantly upgraded software packages, and, potentially, in different geographical locations. Finally, one should keep in mind that automatic or semi-automatic volume measurements perform poorly in subpleural and subsolid nodules, which currently excludes a substantial number of nodules from the assessment with this technology (6).…”