Idiopathic Pulmonary Fibrosis: Data-driven Textural Analysis of Extent of Fibrosis at Baseline and 15-Month Follow-up.

Purpose To evaluate associations between pulmonary function and both quantitative analysis and visual assessment of thin-section computed tomography (CT) images at baseline and at 15-month follow-up in subjects with idiopathic pulmonary fibrosis (IPF). Materials and Methods This retrospective analysis of preexisting anonymized data, collected prospectively between 2007 and 2013 in a HIPAA-compliant study, was exempt from additional institutional review board approval. The extent of lung fibrosis at baseline inspiratory chest CT in 280 subjects enrolled in the IPF Network was evaluated. Visual analysis was performed by using a semiquantitative scoring system. Computer-based quantitative analysis included CT histogram-based measurements and a data-driven textural analysis (DTA). Follow-up CT images in 72 of these subjects were also analyzed. Univariate comparisons were performed by using Spearman rank correlation. Multivariate and longitudinal analyses were performed by using a linear mixed model approach, in which models were compared by using asymptotic χ2 tests. Results At baseline, all CT-derived measures showed moderate significant correlation (P < .001) with pulmonary function. At follow-up CT, changes in DTA scores showed significant correlation with changes in both forced vital capacity percentage predicted (ρ = -0.41, P < .001) and diffusing capacity for carbon monoxide percentage predicted (ρ = -0.40, P < .001). Asymptotic χ2 tests showed that inclusion of DTA score significantly improved fit of both baseline and longitudinal linear mixed models in the prediction of pulmonary function (P < .001 for both). Conclusion When compared with semiquantitative visual assessment and CT histogram-based measurements, DTA score provides additional information that can be used to predict diminished function. Automatic quantification of lung fibrosis at CT yields an index of severity that correlates with visual assessment and functional change in subjects with IPF. © RSNA, 2017.

Radiologic-pathologic discordance in biopsy-proven usual interstitial pneumonia.

The aim of this study was to compare the clinical, radiological and histological findings in a large population of subjects enrolled during a multicentre study of idiopathic pulmonary fibrosis, with a focus on discordance between imaging and histologic diagnoses of usual interstitial pneumonia (UIP).Two independent radiologists retrospectively reviewed 241 subjects who underwent high-resolution computed tomography (HRCT) and surgical lung biopsies. HRCT findings were classified as UIP, possible UIP and inconsistent with UIP. Histological findings were classified as definite, probable, possible and not UIP.Of the 241 cases, 102 (42.3%) had HRCT findings of UIP, 64 (26.6%) had possible UIP and 75 (31.1%) were inconsistent with UIP. Among those with UIP on HRCT, 99 (97.1%) had histologically definite or probable UIP (concordant group), and 71 (94.7%) of those with "inconsistent" HRCT features had histologically definite or probable UIP (discordant group). Discordant subjects were slightly younger and less likely to be smokers than concordant subjects, but no survival differences were identified.In this population of patients enrolled with a diagnosis of idiopathic pulmonary fibrosis, 94.7% of those with HRCT findings "inconsistent with UIP" demonstrated histological UIP. This suggests that the term "inconsistent with UIP" is misleading.

Usual interstitial pneumonia: typical and atypical high-resolution computed tomography features.

The computed tomography appearances of usual interstitial pneumonia (UIP) are usually characteristic, with basal-predominant, peripheral-predominant reticular abnormality and honeycombing. Important complications that may be detected by the radiologist include pulmonary hypertension, lung cancer, and acute exacerbation. As the number of surgical lung biopsies performed for typical UIP declines, histologic findings of UIP are increasingly found in subjects with atypical computed tomographic features. Potential reasons for such discordance may include variability in pathologist interpretation, sampling error on biopsy, biopsy obtained from nonrepresentative site, coexistence of multiple pathologies within the same lung, and familial pulmonary fibrosis. Multidisciplinary diagnosis is critical in resolving these cases.

Accuracy of non-ECG-gated computed tomography angiography of the chest in assessment of left-sided cardiac chamber enlargement.

PURPOSE: To determine whether measurement of left ventricular (LV) and left atrial (LA) diameters on nongated computed tomography angiography (CTA) can detect left atrial and left ventricular enlargement (LAE and LVE) with high specificity. MATERIALS AND METHODS: Ninety-nine patients who had undergone both nongated CTA of the chest and echocardiography within 1 week constituted the pilot group. On CTA, LA and LV diameters were measured in the axial plane and on a 3-chamber-view multiplanar reconstruction. These measurements were compared with echocardiography results. Receiver operating characteristic (ROC) curves were then generated to determine optimal cutoff values for diagnosis of LAE and LVE. These thresholds were applied to a validation group (n = 203), and sensitivities and specificities for cutoff values were determined. Simple κ-coefficients were calculated for interobserver agreement. RESULTS: In the pilot group, axial measurements of the LA and LV diameters were superior to multiplanar reconstruction measurements based on areas under the ROC (LV: 0.82 vs. 0.76, LA: 0.87 vs. 0.82). Using the ROC results, cutoff values of 5.5 and 4.5 cm were chosen for LVE and LAE, respectively. These thresholds were applied to the validation group, achieving an average sensitivity and specificity for LAE of 53% [confidence interval (CI): 37%-71% and 94% (89%-97%)], respectively. Average sensitivity and specificity for LVE were 41% (CI: 23%-59%) and 99% (CI: 96%-100%), respectively. Kappa coefficients for diagnosis of LAE and LVE were 0.70 and 0.81, respectively. CONCLUSION: Thresholds for LA and LV diameter on nongated CTA can be chosen to provide specific, but not sensitive, detection of LAE and LVE.