Possible UIP pattern on high-resolution computed tomography is associated with better survival than definite UIP in IPF patients.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive fibrosing lung disease of unknown etiology. Inter-society consensus guidelines on IPF diagnosis and management outline radiologic patterns including definite usual interstitial pneumonia (UIP), possible UIP, and inconsistent with UIP. We evaluate these diagnostic categories as prognostic markers among patients with IPF. METHODS: Included subjects had biopsy-proven UIP, a multidisciplinary team diagnosis of IPF, and a baseline high-resolution computed tomography (HRCT). Thoracic radiologists assigned the radiologic pattern and documented the presence and extent of specific radiologic findings. The outcome of interest was lung transplant-free survival. RESULTS: IPF patients with a possible UIP pattern on HRCT had significantly longer Kaplan-Meier event-free survival compared to those with definite UIP pattern (5.21 and 3.57 years, respectively, p = 0.002). In a multivariable Cox proportional hazards model adjusted for baseline age, gender, %-predicted FVC, and %-predicted DLCO via the GAP Stage, extent of fibrosis (via the traction bronchiectasis score) and ever-smoker status, possible UIP pattern on HRCT (versus definite UIP) was associated with reduced hazard of death or lung transplant (HR = 0.42, CI 95% 0.23-0.78, p = 0.006). CONCLUSIONS: Radiologic diagnosis categories outlined by inter-society consensus guidelines is a widely-reported and potentially useful prognostic marker in IPF patients, with possible UIP pattern on HRCT associated with a favorable prognosis compared to definite UIP pattern, after adjusting for relevant covariates.

CT Pulmonary Angiography: Using Decision Rules in the Emergency Department.

PURPOSE: The aim of this study was to assess the appropriateness of utilization and diagnostic yields of CT pulmonary angiography (CTPA), comparing two commonly applied decision rules, the pulmonary embolism (PE) rule-out criteria (PERC) and the modified Wells criteria (mWells), in the emergency department (ED) setting. METHODS: Institutional review board approval was obtained for this HIPAA-compliant, prospective-cohort, academic single-center study. Six hundred two consecutive adult ED patients undergoing CTPA for suspected PE formed the study population. The outcome was positive or negative for PE by CTPA and at 6-month follow-up. PERC and mWells scores were calculated. A positive PERC score was defined as meeting one or more criteria and a positive mWells score as >4. The percentage of CT pulmonary angiographic examinations that could have been avoided and the diagnostic yield of CTPA using PERC, mWells, and PERC applied to a negative mWells score were calculated. RESULTS: The diagnostic yield of CTPA was 10% (61 of 602). By applying PERC, mWells, and PERC to negative mWells score, 17.6% (106 of 602), 45% (273 of 602), and 17.1% (103 of 602) of CT pulmonary angiographic examinations, respectively, could have been avoided. The diagnostic yield in PERC-positive patients was higher than in mWells-positive patients (10% [59 of 602] vs 8% [49 of 602], P < .0001). Among PERC-negative and mWells-negative patients, the diagnostic yields for PE were 1.9% (2 of 106) and 4% (12 of 273), respectively (P = .004). The diagnostic yield of a negative PERC score applied to a negative mWells score was 1.9% (2 of 103). CONCLUSIONS: The use of PERC in the ED has the potential to significantly reduce the utilization of CTPA and misses fewer cases of PE compared with mWells, and it is therefore a more efficient decision tool.

Effect of CAD on radiologists' detection of lung nodules on thoracic CT scans: analysis of an observer performance study by nodule size.

RATIONALE AND OBJECTIVES: To retrospectively investigate the effect of a computer-aided detection (CAD) system on radiologists' performance for detecting small pulmonary nodules in computed tomography (CT) examinations, with a panel of expert radiologists serving as the reference standard. MATERIALS AND METHODS: Institutional review board approval was obtained. Our dataset contained 52 CT examinations collected by the Lung Image Database Consortium, and 33 from our institution. All CTs were read by multiple expert thoracic radiologists to identify the reference standard for detection. Six other thoracic radiologists read the CT examinations first without and then with CAD. Performance was evaluated using free-response receiver operating characteristics (FROC) and the jackknife FROC analysis methods (JAFROC) for nodules above different diameter thresholds. RESULTS: A total of 241 nodules, ranging in size from 3.0 to 18.6 mm (mean, 5.3 mm) were identified as the reference standard. At diameter thresholds of 3, 4, 5, and 6 mm, the CAD system had a sensitivity of 54%, 64%, 68%, and 76%, respectively, with an average of 5.6 false positives (FPs) per scan. Without CAD, the average figures of merit (FOMs) for the six radiologists, obtained from JAFROC analysis, were 0.661, 0.729, 0.793, and 0.838 for the same nodule diameter thresholds, respectively. With CAD, the corresponding average FOMs improved to 0.705, 0.763, 0.810, and 0.862, respectively. The improvement achieved statistical significance for nodules at the 3 and 4 mm thresholds (P = .002 and .020, respectively), and did not achieve significance at 5 and 6 mm (P = .18 and .13, respectively). At a nodule diameter threshold of 3 mm, the radiologists' average sensitivity and FP rate were 0.56 and 0.67, respectively, without CAD, and 0.67 and 0.78 with CAD. CONCLUSION: CAD improves thoracic radiologists' performance for detecting pulmonary nodules smaller than 5 mm on CT examinations, which are often overlooked by visual inspection alone.