Faculty Bibliography

PURPOSE/OBJECTIVE:The purpose of this article was to determine whether a novel finding on coronal computed tomography (CT) can help differentiate usual interstitial pneumonia (UIP) from nonspecific interstitial pneumonia (NSIP) in order to obviate lung biopsy. MATERIALS AND METHODS/METHODS:Two chest radiologists, blinded to clinical data, reviewed 3 preselected coronal images from CT scans, performed within 1 year of surgical lung biopsy (SLB), from 51 patients with biopsy-proven UIP and 15 with biopsy-proven NSIP. The 198 (66×3) images were anonymized and randomized. The radiologists assessed each coronal image for the presence or absence of the straight-edge sign (SES) on both the right and left sides, anecdotally thought to be more common in NSIP than in UIP. The SES was defined as reticulation isolated to the lung bases with sharp demarcation in the craniocaudal plane and without substantial extension along the lateral margins of the lungs. A validation cohort from a second medical center was also evaluated to reassess our findings. RESULTS:The absence of a bilateral SES yielded a sensitivity, specificity, positive predictive value (PPV), and negative predictive value of 56.9%, 93.3%, 96.7%, and 38.9%, respectively, for UIP on SLB. The unilateral or bilateral absence of the SES yielded a sensitivity, specificity, PPV, and negative predictive value of 76.5%, 66.7%, 88.6%, and 45.5%, respectively, for UIP on SLB. For the 11 subjects with an overall CT pattern consistent with NSIP but a pathologic diagnosis of UIP, the SES was absent in 6 (54.5%) subjects. In the validation cohort, the SES was much more common in NSIP than in UIP (46.6% compared with 3.3%, respectively; P<0.001). CONCLUSION/CONCLUSIONS:The absence of the SES has a high PPV for biopsy-proven UIP. Bilateral absence of the SES has high specificity (93.3%) for biopsy-proven UIP. The SES may be useful for differentiating UIP from NSIP.

RATIONALE:Hypersensitivity pneumonitis is a complex lung disease resulting from repeated inhalation of a variety of antigens. Limited data exist regarding its epidemiology. OBJECTIVES:To describe the trends in the annual incidence and prevalence of hypersensitivity pneumonitis in the United States. METHODS:We developed novel claims-based coding algorithms to identify hypersensitivity pneumonitis, chronic hypersensitivity pneumonitis, and fibrotic hypersensitivity pneumonitis cases using the 2004 to 2013 MarketScan Commercial and Medicare Supplemental healthcare claims databases. Algorithm validity and reliability were assessed with clinical data from National Jewish Health. We calculated yearly cumulative incidence and prevalence overall and by age. For the subgroup with vital status, Kaplan-Meier methods were used to analyze survival stratified by evidence of fibrosis. RESULTS:We identified 7,498 cases that met our hypersensitivity pneumonitis definition over the 10-year study period, including 3,902 with chronic hypersensitivity pneumonitis and 1,852 with fibrotic hypersensitivity pneumonitis. On the basis of the clinical-radiological adjudication of the validation sample, 38 cases (95%) were confirmed as hypersensitivity pneumonitis. The mean age was 52 years, and 58% were women. The 1-year prevalence rates for hypersensitivity pneumonitis ranged from 1.67 to 2.71 per 100,000 persons, and 1-year cumulative incidence rates ranged from 1.28 to 1.94 per 100,000 persons. The prevalence increased with age, ranging from 0.95 per 100,000 among 0- to 9-year-olds to 11.2 per 100,000 among those aged 65 years and older. Between 56 and 68% of hypersensitivity pneumonitis cases in each year were classified as chronic hypersensitivity pneumonitis (prevalence, 0.91-1.70 per 100,000 persons; cumulative incidence, 0.63-1.08 per 100,000 persons). Fewer had fibrotic hypersensitivity pneumonitis (prevalence, 0.41-0.80 per 100,000 persons; cumulative incidence: 0.29-0.43 per 100,000 persons). Most cases (74%) were classified as unspecified hypersensitivity pneumonitis. Older age, male sex, and fibrosis were associated with higher mortality rates in unadjusted analyses. CONCLUSIONS:Using U.S. administrative claims-based data, we developed an algorithm with a high sensitivity and specificity for hypersensitivity pneumonitis. Between 2004 and 2013, hypersensitivity pneumonitis was more common among women and those older than 65 years. Most cases were classified as chronic hypersensitivity pneumonitis. Approximately one-fourth met our criteria for fibrotic hypersensitivity pneumonitis, which was associated with a higher mortality rate.

OBJECTIVE:Incidental pulmonary findings are commonly detected at lung cancer screening chest CT. Though most of these findings are clinically insignificant, it is difficult to prospectively determine which are potentially important to clinical care. The purpose of this review is to discuss the incidental pulmonary findings commonly detected at lung cancer screening chest CT. CONCLUSION/CONCLUSIONS:Incidental pulmonary findings most commonly fall into one of three categories: interstitial lung disease, emphysema, and airways disease (both small and large airways).

RATIONALE/BACKGROUND:Significant heterogeneity of computed tomography (CT) presentation exists within chronic hypersensitivity pneumonitis (HP). There are limited data aimed at delineating the prognostic value of specific CT features, distribution, and patterns in chronic HP. OBJECTIVES/OBJECTIVE:To examine whether the presence of CT mosaic attenuation (MA) and air trapping (AT), and the distribution or patterns of fibrosis impact survival in subjects with chronic HP. METHODS:We retrospectively identified 110 consecutively enrolled, well-characterized, biopsy-proven adult subjects with chronic HP between 1982 and 2015 from the National Jewish Health interstitial lung disease research database. The first available CT scan of diagnostic quality from each subject was formally evaluated for specific CT findings associated with chronic HP and for overall CT pattern. A Cox proportional hazards model was used to identify independent predictors in time-to-death analysis, and bootstrap analysis was performed for internal model validation. RESULTS:Fibrotic HP (65%; 72/110) was most often peripheral in the axial plane and lower lung preponderant. The distribution of lung disease in those without fibrosis was most often axially and zonally diffuse. There was no association between survival and CT distribution or CT pattern in the whole cohort or within the fibrotic subset of subjects. After multivariate adjustment, AT/MA was independently associated with survival in the whole cohort (HR = 0.26; 95% confidence interval = 0.07-0.97). Results were similar after restricting the analyses to fibrotic HP cases. CONCLUSIONS:Among subjects with chronic HP, the presence of CT AT/MA may identify subjects with better prognosis.

Asthma is one of the most common diseases of the lung. Asthma manifests with common, although often subjective and nonspecific, imaging features at radiography and high-resolution computed tomography. The primary role of imaging is not to make a diagnosis of asthma but to identify complications, such as allergic bronchopulmonary aspergillosis, or mimics of asthma, such as hypersensitivity pneumonitis. This article reviews the imaging features of asthma as well as common complications and mimics.

The idiopathic interstitial pneumonias are a group of inflammatory and fibrosing pulmonary conditions that share many clinical, radiologic, and histologic similarities. Radiologic evaluation can often help to make a more confident diagnosis of these conditions and may help in their management. Several specific radiologic findings can suggest a single best diagnosis or can help to differentiate between similar conditions. Imaging findings can also have important prognostic implications or identify complications. This review discusses the role of radiologic findings in the setting of the idiopathic interstitial pneumonias.