Visual versus Automated Evaluation of Chest Computed Tomography for the Presence of Chronic Obstructive Pulmonary Disease.

Contains fulltext : 110186.pdf (publisher's version ) (Open Access)BACKGROUND: Incidental CT findings may provide an opportunity for early detection of chronic obstructive pulmonary disease (COPD), which may prove important in CT-based lung cancer screening setting. We aimed to determine the diagnostic performance of human observers to visually evaluate COPD presence on CT images, in comparison to automated evaluation using quantitative CT measures. METHODS: This study was approved by the Dutch Ministry of Health and the institutional review board. All participants provided written informed consent. We studied 266 heavy smokers enrolled in a lung cancer screening trial. All subjects underwent volumetric inspiratory and expiratory chest computed tomography (CT). Pulmonary function testing was used as the reference standard for COPD. We evaluated the diagnostic performance of eight observers and one automated model based on quantitative CT measures. RESULTS: The prevalence of COPD in the study population was 44% (118/266), of whom 62% (73/118) had mild disease. The diagnostic accuracy was 74.1% in the automated evaluation, and ranged between 58.3% and 74.3% for the visual evaluation of CT images. The positive predictive value was 74.3% in the automated evaluation, and ranged between 52.9% and 74.7% for the visual evaluation. Interobserver variation was substantial, even within the subgroup of experienced observers. Agreement within observers yielded kappa values between 0.28 and 0.68, regardless of the level of expertise. The agreement between the observers and the automated CT model showed kappa values of 0.12-0.35. CONCLUSIONS: Visual evaluation of COPD presence on chest CT images provides at best modest accuracy and is associated with substantial interobserver variation. Automated evaluation of COPD subjects using quantitative CT measures appears superior to visual evaluation by human observers

Towards a close computed tomography monitoring approach for screen detected subsolid pulmonary nodules?

Pulmonary subsolid nodules (SSNs) have a high likelihood of malignancy, but are often indolent. A conservative treatment approach may therefore be suitable. The aim of the current study was to evaluate whether close follow-up of SSNs with computed tomography may be a safe approach. The study population consisted of participants of the Dutch-Belgian lung cancer screening trial (Nederlands Leuvens Longkanker Screenings Onderzoek; NELSON). All SSNs detected during the trial were included in this analysis. Retrospectively, all persistent SSNs and SSNs that were resected after first detection were segmented using dedicated software, and maximum diameter, volume and mass were measured. Mass doubling time (MDT) was calculated. In total 7135 volunteers were included in the current analysis. 264 (3.3%) SSNs in 234 participants were detected during the trial. 147 (63%) of these SSNs in 126 participants disappeared at follow-up, leaving 117 persistent or directly resected SSNs in 108 (1.5%) participants available for analysis. The median follow-up time was 95 months (range 20-110 months). 33 (28%) SSNs were resected and 28 of those were (pre-) invasive. None of the non-resected SSNs progressed into a clinically relevant malignancy. Persistent SSNs rarely developed into clinically manifest malignancies unexpectedly. Close follow-up with computed tomography may be a safe option to monitor changes

Between and within observer agreement for semi-automatic subsolid nodule measurements.

<p>Data given are intraclass correlation coefficients.</p

Illustration of manual and semi-automatic nodule segmentation on CT.

<p>The semi-automatic measurement is presented on the left, and the manual measurement on the right. At the right side of both images are 3 zoomed images from top to bottom axial, coronal and sagital plane. Note the irregularity of the manual measurements in the coronal and sagital plane. This is because manual segmentations are done in the axial plane, while semi-automatic measurements are truly 3D.</p

Erratum: Towards a close computed tomography monitoring approach for screen detected subsolid pulmonary nodules? (vol 45, pg 765, 2015)

Biological, physical and clinical aspects of cancer treatment with ionising radiatio

Bland-Altman plots for two observers of relative differences between manual and semi-automatic measurements of subsolid nodules on CT for diameter (top row), volume (middle row) and mass (bottom row).

<p>Bland-Altman plots for two observers of relative differences between manual and semi-automatic measurements of subsolid nodules on CT for diameter (top row), volume (middle row) and mass (bottom row).</p

Semi-Automatic Quantification of Subsolid Pulmonary Nodules:Comparison with Manual Measurements

<p>Rationale: Accurate measurement of subsolid pulmonary nodules (SSN) is becoming increasingly important in the management of these nodules. SSNs were previously quantified with time-consuming manual measurements. The aim of the present study is to test the feasibility of semi-automatic SSNs measurements and to compare the results to the manual measurements.</p><p>Methods: In 33 lung cancer screening participants with 33 SSNs, the nodules were previously quantified by two observers manually. In the present study two observers quantified these nodules by using semi-automated nodule volumetry software. Nodules were quantified for effective diameter, volume and mass. The manual and semi-automatic measurements were compared using Bland-Altman plots and paired T tests. Observer agreement was calculated as an intraclass correlation coefficient. Data are presented as mean (SD).</p><p>Results: Semi-automated measurements were feasible in all 33 nodules. Nodule diameter, volume and mass were 11.2 (3.3) mm, 935 (691) ml and 379 (311) milligrams for observer 1 and 11.1 (3.7) mm, 986 (797) ml and 399 (344) milligrams for observer 2, respectively. Agreement between observers and within observer 1 for the semi-automatic measurements was good with an intraclass correlation coefficient >0.89. For observer 1 and observer 2, measured diameter was 8.8% and 10.3% larger (p</p><p>Conclusion: Semi-automated measurement of the diameter, volume and mass of SSNs is feasible with good observer agreement. Semi-automated measurement makes quantification of mass and volume feasible in daily practice.</p>

Expertise levels and experience of the human observers.

a<p>level of expertise based as on Reference <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0042227#pone.0042227-tenCate1" target="_blank">[24]</a>: <i>I</i> has knowledge and some skills, <i>II</i> acts under full supervision, <i>III</i> acts under limited supervision, <i>IV</i> acts without supervision, <i>V</i> supervises and teaches;</p>b<p>Years since the observer started reading and evaluating chest CT scans; Observer 1 to 5 were considered ‘less experienced observers’ and observer 6 to 8 were considered ‘experienced observers’.</p

Comparison between the included subsample of participants and the total cohort of screening participants in the study period between July 2007–September 2008.

<p>Comparison using Mann-Whitney U test revealed no significant differences between the two groups.</p>a<p>data in the randomly selected subsample of male participants;</p>b<p>data in the total group of male participants screened in the study period</p