Benedikt H. Heidinger

Lung Adenocarcinoma Manifesting as Pure Ground-Glass Nodules: Correlating CT Size, Volume, Density, and Roundness with Histopathologic Invasion and Size

Objectives The aims of this study were to quantify the relationship between computed tomography (CT) size, volume, density, and roundness of lung adenocarcinomas (ACs) manifesting as pure ground‐glass nodules (pGGNs) on CT images and to correlate these parameters with histologic features of invasiveness. Methods From 2005 to 2015, 63 ACs manifesting as pGGNs on CT images were surgically resected at our institution. CT size was measured, and roundness, volumes and densities were computed. CT parameters were correlated to age and sex, as well as to size and number of invasive foci and histologic AC subcategories. Correlations were quantified with Spearman rank correlation coefficients. Results Of 63 ACs, 28 (44%) were AC in situ, 25 (40%) were minimally invasive AC, and 10 (16%) were invasive AC. Six of 35 nodules with invasive foci (17%) were smaller than 10 mm. Correlations between age and CT size, volume, density, and roundness were not significant (range r = –0.061 to 0.144, p = 0.285 to 0.902). Correlations between size and number of invasive foci with CT size (r = 0.417, p < 0.001 and r = 0.389, p = 0.003, respectively) were similar to the correlations with volume (r = 0.401, p = 0.001 and r = 0.350, p = 0.005, respectively) and stronger than the correlation with density (r = 0.237, p = 0.062 and r = 0.222, p = 0.081, respectively) and roundness (r = 0.059, p = 0.648 and r = –0.030, p = 0.831, respectively). Conclusions In ACs manifesting as pGGNs on CT images, nodule size is positively related to size and number of histologically invasive foci. However, invasive foci can be found in pGGNs smaller than 10 mm. Measuring volume and density of pGGNs provides no advantage over two‐dimensional size measurements, which appear sufficient for risk estimation in clinical practice.

Measurement Bias of Gross Pathologic Compared With Radiologic Tumor Size of Resected Lung AdenocarcinomasImplications for the T-Stage Revisions in the Eighth Edition of the American Joint Committee on Cancer Staging Manual

Objectives The eighth edition of the AJCC Cancer Staging Manual now stratifies the T descriptor for lung cancers by each increasing 1.0 cm increment, up to 5.0 cm, with an additional category for tumor greater than 7.0 cm. Bias in pathologic versus radiologic measurements may impact tumor staging. Methods The gross pathologic measurements of 493 resected lung adenocarcinomas were compared with presurgical computed tomography radiologic measurements. Also, pathologic tumor measurement data from the Surveillance, Epidemiology, and End Results (SEER) program database were examined. Results The distribution of pathologic measurements showed clustering at 0.5-cm increments, with 43.0% of pathologic measurements falling on 0.5-cm increments compared to only 20.3% of radiologic measurements. This pathologic measurement clustering was also observed for both 591,691 resected lung cancers and 3,597,685 tumors of any type from the SEER database. Conclusions Compared to radiologic measurements, gross pathologic measurements cluster around whole- and half-cm values. This measurement bias could lead to incorrect pathologic tumor staging and influence clinical treatment plans.

Size Measurement and T-staging of Lung Adenocarcinomas Manifesting as Solid Nodules ≤30 mm on CT

RATIONALE AND OBJECTIVES This study aimed to compare long-axis diameter to average computed tomography (CT) diameter measurements of lung adenocarcinomas manifesting as solid lung nodules ≤30 mm on CT, as referenced to pathologic measurements, and to determine the impact of the two CT measurement approaches on tumor (T)-staging of nodules. MATERIALS AND METHODS This institutional review board-approved study included all 274 radiologic solid adenocarcinomas resected at our institution over 10 years. Two observers measured long- and short-axis diameters on pre-resection chest CT in lung and mediastinal windows. T-stages were determined. CT measurements and T-stages were compared to pathology measurements and T-stages using Wilcoxon signed rank test and McNemar test. Inter- and intraobserver variability was determined with intraclass correlation coefficients (ICC) and Bland-Altman plots. RESULTS For lung and mediastinal windows, nodule size was significantly larger using long-axis diameter rather than average diameter (16.93 vs. 14.92 mm, P <.001; and 14.02 vs. 12.17 mm, P <.001, respectively). The correlation of CT with pathologic measurements was stronger with long-axis than with average diameter (ICC 0.808 vs. 0.730; and 0.731 vs. 0.621, respectively). Lung window measurements correlated stronger with pathology than mediastinal window measurements. CT T-stages differed from pathology T-stages in more than 20% of nodules (P <.001). Inter- and intraobserver variability was small with long-axis and average diameter (ICC range 0.96-0.991, and 0.970-0.993, respectively), but long-axis diameter showed wider scatter on Bland-Altman plots. CONCLUSIONS Long-axis CT diameter is preferable for T-staging because it better reflects the pathology T-stage. Average CT diameter might be used for longitudinal nodule follow-up because it shows less measurement variability and is more conservative in size assessment.

Software-based risk stratification of pulmonary adenocarcinomas manifesting as pure ground glass nodules on computed tomography

AbstractObjectivesTo assess the performance of the “Computer-Aided Nodule Assessment and Risk Yield” (CANARY) software in the differentiation and risk assessment of histological subtypes of lung adenocarcinomas manifesting as pure ground glass nodules on computed tomography (CT).Methods64 surgically resected and histologically proven adenocarcinomas manifesting as pure ground-glass nodules on CT were assessed using CANARY software, which classifies voxel-densities into three risk components (low, intermediate, and high risk). Differences in risk components between histological adenocarcinoma subtypes were analysed. To determine the optimal threshold reflecting the presence of an invasive focus, sensitivity, specificity, negative predictive value, and positive predictive value were calculated.Results28/64 (44%) were adenocarcinomas in situ (AIS); 26/64 (41%) were minimally invasive adenocarcinomas (MIA); and 10/64 (16%) were invasive ACs (IAC). The software showed significant differences in risk components between histological subtypes (P<0.001–0.003). A relative volume of 45% or less of low-risk components was associated with histological invasiveness (specificity 100%, positive predictive value 100%).ConclusionsCANARY-based risk assessment of ACs manifesting as pure ground glass nodules on CT allows the differentiation of their histological subtypes. A threshold of 45% of low-risk components reflects invasiveness in these groups.Key points• CANARY-based risk assessment allows the differentiation of their histological subtypes. • 45% or less of low-risk component reflects histological invasiveness. • CANARY has potential role in suspected adenocarcinomas manifesting as pure ground-glass nodules.

Diagnosing Sarcopenia on Thoracic Computed Tomography: Quantitative Assessment of Skeletal Muscle Mass in Patients Undergoing Transcatheter Aortic Valve Replacement

RATIONALE AND OBJECTIVES This study aims to assess the use of skeletal muscle mass measurements at two thoracic levels to diagnose sarcopenia on computed tomography (CT) chest examinations and to analyze the impact of these measurements on clinical outcome parameters following transcatheter aortic valve replacement. MATERIALS AND METHODS This study retrospectively included 157 patients who underwent preoperative CT examinations. The total muscle area was measured on transverse CT images at the 3rd lumbar and 7th and 12th thoracic levels with skeletal muscle indices (SMIs) calculated at each level. SMIs were then compared to clinical outcome parameters, and thoracic cutoff values for sarcopenia at the 7th and 12th thoracic levels were calculated. RESULTS Correlation between SMIs at the third lumbar vertebra (L3) and the 12th thoracic vertebra (T12) was stronger (r = 0.724, P < 0.001) than that between L3 and the seventh thoracic vertebra (T7) (r = 0.594, P < 0.001). SMIs at L3 and T12 significantly correlated with prolonged length of stay. Thoracic cutoff values for the 12th thoracic level were 42.6 cm2/m2 (men) and 30.6 cm2/m2 (women), and those for the 7th thoracic level were 46.5 cm2/m2 (men) and 32.3 cm2/m2 (women). CONCLUSIONS Skeletal muscle measurements at the T12 level could permit the diagnosis of sarcopenia and could be used to correlate sarcopenia with outcome parameters in patients undergoing CT limited to the chest.

Imaging the posterior mediastinum: a multimodality approach

The posterior mediastinum contains several structures that can produce a wide variety of pathologic conditions. Descending thoracic aorta, esophagus, azygos and hemiazygos veins, thoracic duct, lymph nodes, adipose tissue, and nerves are all located in this anatomical region and can produce diverse abnormalities. Although chest radiography may detect many of these pathologic conditions, computed tomography and magnetic resonance are the imaging modalities of choice for further defining the relationship of posterior mediastinal lesions to neighboring structures and showing specific imaging features that narrow the differential diagnosis. This review emphasizes modality-related answers to morphologic questions, which provide precise diagnostic information.

“Rounding” the Size of Pulmonary Nodules: Impact of Rounding Methods on Nodule Management, as Defined by the 2017 Fleischner Society Guidelines

RATIONALE AND OBJECTIVES The objective of this study was to quantify the impact of different rounding methods on size measurements of pulmonary nodules and to determine the number of nodules that change management categories as a result of rounding. MATERIALS AND METHODS For this retrospective institutional review board-approved study, we included 503 incidental pulmonary nodules (308 solid and 195 subsolid) from a data repository. Long and short axes were measured. Average diameters were calculated using four different rounding methods (method 1: no rounding; method 2: rounding only the average diameter to the closest millimeter; method 3: rounding only short and long axes; and method 4: rounding short and long axes and the average diameter to the closest millimeter). Nodules were classified for each rounding method according to the 2017 Fleischner Society guideline management categories. Measurements were compared among the four rounding methods using analysis of variance. RESULTS Without rounding, the average nodule diameter was 15.67 ± 5.97 mm. This increased between 0.03  and 0.29 mm using rounding methods 2-4 (range: P < 0.001-0.017). The nodule size was more frequently rounded up (range: 52.1%-77.5%) than rounded down (range: 17.7%-42.5%) using rounding methods 2-4, as compared to no rounding. In the 308 solid nodules, up to 2.9% of the nodules changed management category, whereas none of the 195 subsolid nodules changed category. CONCLUSIONS Rounding methods have a small absolute but statically significant effect on nodule size, impacting management category in less than 3% of the nodules. This suggests that, in clinical practice, any rounding method can be used for determining nodule size without substantially biasing individual nodules toward given management categories.

Cine MRI of Tracheal Dynamics in Healthy Volunteers and Patients With Tracheobronchomalacia

OBJECTIVE Bronchoscopy and MDCT are routinely used to assess tracheobronchomalacia (TBM). Recently, dynamic MRI (cine MRI) has been proposed as a radiation-free alternative to MDCT. In this study, we tested cine MRI assessment of airway dynamics during various breathing conditions and compared cine MRI and MDCT measurements in healthy volunteers and patients with suspected TBM. CONCLUSION Cine MRI was found to be a technically feasible alternative to MDCT for assessing central airway dynamics.

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

Accurate size measurements of pulmonary nodules on CT are a prerequisite for accurate nodule management, given that all current management guidelines are based on nodule size (1-4). 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).

Pathologic T Descriptor of Nonmucinous Lung Adenocarcinomas Now Based on Invasive Tumor Size

Objectives The eighth edition of the American Joint Committee on Cancer staging manual now stratifies nonmucinous lung adenocarcinomas (nmLACAs) by the size of the invasive component only. This is determined by direct gross or microscopic measurement; however, a calculated invasive size based on the percentage of invasive growth patterns has been proposed as an alternative option. Methods To compare radiologic with different pathologic assessments of invasive tumor size, we retrospectively reviewed a cohort of resected nmLACAs with a part-solid appearance on computed tomography (CT) scan (n = 112). Results The median direct microscopic pathologic invasive measurements were not significantly different from the median calculated pathologic invasive measurements; however, the median CT invasive measurements were 0.26 cm larger than the median direct pathologic measurements (P < .001). Conclusions Our results show that pathologic calculated invasive tumor measurements are comparable to direct microscopic measurements of invasive tumor, thereby supporting the recommendation for use of calculated invasive tumor size by the pathologist if necessary.