One-dimensional quantitative evaluation of peripheral lung adenocarcinoma with or without ground-glass opacity on thin-section CT images using profile curves

Abstract

The purpose of our investigation was to compare the usefulness of the subjective visual assessment of ground-glass opacity (GGO) with a quantitative method that used a profile curve to determine prognosis. 96 adenocarcinomas were studied. Three diameters ([D1]-[D3]) were defined for estimating the diameter of tumours on the monitor: the distance between two points was measured using software that displays a CT density profile across the tumour. One experienced and one less experienced radiologist independently evaluated the following six parameters: the three diameters [D1]-[D3]; the solid portion of total tumour in the two different ratios ([D2]/[D1], [D3]/[D1]); and the area ratio of GGO for total opacity to subjective visual evaluation. Interobserver agreement between the two radiologists of the diameters (mean bias+/- 1.96 standard deviations) was as follows: [D1], -0.7 +/- 6 mm; [D2], 0.4 +/- 4.4 mm; and [D3], -0.1 +/- 4.2 mm (Bland and Altman's method). Interobserver agreement was fair in evaluating the area ratio of GGO (kappa test, kappa = 0.309). Univariate logistic regression analysis revealed that two ratios ([D2]/[D1], [D3]/[D1]) might be significantly useful in estimating lymph node metastasis (p < 0.026), lymph duct invasion (p < 0.001) and recurrence (p < 0.015). Observation of the area ratio of GGO by an experienced radiologist would be necessary for estimating lymph node metastasis (p = 0.04) and lymph duct invasion (p < 0.001). We concluded that the ratio of solid component to total tumour, which is obtainable in a more objective and simple way using profile curves obtained by software, is a more useful method of estimating prognosis than is visual assessment.

Automated assessment of malignant degree of small peripheral adenocarcinomas using volumetric CT data: Correlation with pathologic prognostic factors

“…The prognosis of pulmonary adenocarcinoma with a larger area of GGO on thin-section CT images is much better than that of pulmonary adenocarcinoma of solid type on CT regardless of its maximal tumor dimension [4,[16][17][18][19][20][21]. The extent of GGO is one of the most important prognostic factors.…”

Detection and quantification of the solid component in pulmonary subsolid nodules by semiautomatic segmentation

“…Several other papers report on attempts for objective methods other than the calculation of GGO ratio and TDR to evaluate the quantitative aspects and characterization of an SSN [19][20][21][22][23][24]. Some use a one-dimensional analysis [22,24] by measuring the diameter or a combination of diameter and density of the components of an SSN on a one-dimensional histogram of the nodule.…”

“…Some use a one-dimensional analysis [22,24] by measuring the diameter or a combination of diameter and density of the components of an SSN on a one-dimensional histogram of the nodule. Yanagawa et al [22] in a study of 96 adenocarcinomas concluded that for the ratio of solid component to total tumour, using the profile curves is more useful in estimating prognostic factors than visual assessment.…”

“…Some use a one-dimensional analysis [22,24] by measuring the diameter or a combination of diameter and density of the components of an SSN on a one-dimensional histogram of the nodule. Yanagawa et al [22] in a study of 96 adenocarcinomas concluded that for the ratio of solid component to total tumour, using the profile curves is more useful in estimating prognostic factors than visual assessment. Kitami et al [23] concluded that a mean CT density value measured on a line through the maximum diameter of the nodule is useful to select between "follow-up or resection" strategies, and that lesions smaller than 1 cm and a mean CT density lower than −600 HU are pre-invasive.…”

Lung nodules: size still matters

“…Likewise, the ratio of the solid component to total tumour is related with tumour histology and therefore is a useful method of estimating prognosis [128,129].…”