Recommendations for Measuring Pulmonary Nodules at CT: A Statement from the Fleischner Society

Abstract

These recommendations for measuring pulmonary nodules at computed tomography (CT) are a statement from the Fleischner Society and, as such, incorporate the opinions of a multidisciplinary international group of thoracic radiologists, pulmonologists, surgeons, pathologists, and other specialists. The recommendations address nodule size measurements at CT, which is a topic of importance, given that all available guidelines for nodule management are essentially based on nodule size or changes thereof. The recommendations are organized according to practical questions that commonly arise when nodules are measured in routine clinical practice and are, together with their answers, summarized in a table. The recommendations include technical requirements for accurate nodule measurement, directions on how to accurately measure the size of nodules at the workstation, and directions on how to report nodule size and changes in size. The recommendations are designed to provide practical advice based on the available evidence from the literature; however, areas of uncertainty are also discussed, and topics needing future research are highlighted. RSNA, 2017 Online supplemental material is available for this article.

Lung nodules: size still matters

“…When considering small SSNs (<1 cm) the variability in measuring nodule dimension was lower when using the average diameter than the longest one [46]. The latest statement from the Fleischner Society on nodule measurements supports this evidence and recommends the expression of the dimension of SSNs <1 cm as average diameter, as for solid nodules [44].…”

“…A following statement focused on recommendations for measuring pulmonary nodules clarified that for nodules <1 cm the dimension should be expressed as average diameter, while for larger nodules both short-and long-axis diameters taken on the same plane should be reported [44].…”

“…Therefore, on the basis of the updated literature, recommendations from the Fleischner Society suggest the use of the lung window setting and the high spatial frequency (sharp) filter to judge the presence of a solid component, and the measurement of both the solid and nonsolid portions in a PSN. The same display window setting is recommended for measuring solid nodules [44].…”

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).…”

Adenocarcinoma in pure ground glass nodules: histological evidence of invasion and open debate on optimal management

“…This observation offers a practical approach, which is particularly convenient for the clinical practice: manual caliper is the simplest and most available method for nodule quantification (13), meanwhile it seems to be as good as volumetry for risk stratification, the latter is a more complex method and has limited availability in the clinical workflow. As the authors report, the manual caliper finds its application in the single time-point assessment of the pGGN.…”