Development and validation of a radiological diagnosis model for hypersensitivity pneumonitis.

High-resolution computed tomography (HRCT) may be useful for diagnosing hypersensitivity pneumonitis. Here, we develop and validate a radiological diagnosis model and model-based points score.Patients with interstitial lung disease seen at the University of Michigan Health System (derivation cohort) or enrolling in the Lung Tissue Research Consortium (validation cohort) were included. A thin-section, inspiratory HRCT scan was required. Thoracic radiologists documented radiological features.The derivation cohort comprised 356 subjects (33.9% hypersensitivity pneumonitis) and the validation cohort comprised 424 subjects (15.5% hypersensitivity pneumonitis). An age-, sex- and smoking status-adjusted logistic regression model identified extent of mosaic attenuation or air trapping greater than that of reticulation ("MA-AT>Reticulation"; OR 6.20, 95% CI 3.53-10.90; p<0.0001) and diffuse axial disease distribution (OR 2.33, 95% CI 1.31-4.16; p=0.004) as hypersensitivity pneumonitis predictors (area under the receiver operating characteristic curve 0.814). A model-based score >2 (1 point for axial distribution, 2 points for "MA-AT>Reticulation") has specificity 90% and positive predictive value (PPV) 74% in the derivation cohort and specificity 96% and PPV 44% in the validation cohort. Similar model performance is seen with population restriction to those reporting no exposure (score >2: specificity 91%).When radiological mosaic attenuation or air trapping are more extensive than reticulation and disease has diffuse axial distribution, hypersensitivity pneumonitis specificity is high and false diagnosis risk low (<10%), but PPV is diminished in a low-prevalence setting.

Increased epicardial fat is independently associated with the presence and chronicity of atrial fibrillation and radiofrequency ablation outcome.

OBJECTIVE: To determine whether intrathoracic fat volumes are associated with presence and chronicity of atrial fibrillation (AF) and radiofrequency ablation (RFA) treatment outcome. METHODS: IRB approval was obtained and patient consent was waived for this HIPAA-compliant retrospective study. 169 patients with AF (75 non-paroxysmal and 94 paroxysmal) and 62 control patients underwent cardiac CT examination. Extrapericardial (EPFV) and epicardial fat volumes (EFV) were measured on CT, the sum of which is the total intrathoracic fat volume. Associations between these three fat volumes and presence and chronicity of AF, and outcome after RFA, were evaluated using logistic regression analysis. RESULTS: EFV was significantly associated with presence [OR 1.01 (95 % CI 1.003-1.03), p = 0.01], chronicity of AF [1.008 (1.001-1.020), p = 0.03] and AF recurrence after RFA [1.009 (1.001-1.01), p = 0.02] after adjustment for age, gender and BMI. Patients with a larger EFV had a shorter time to AF recurrence (p = 0.017) and a higher rate of recurrence (54 % vs 46 %) (p = 0.002) after RFA. EPFV had no significant associations. CONCLUSION: Increased epicardial fat is associated with the presence and chronicity of AF, a higher probability of AF recurrence after RFA and a shorter AF-free interval. KEY POINTS: • Increased epicardial fat is associated with presence and chronicity of atrial fibrillation • Extensive epicardial fat is associated with earlier recurrences of AF after ablation • Extensive epicardial fat may reduce transmurality of ablation by affecting current dynamics.

Smoking-related idiopathic interstitial pneumonia.

Cigarette smoking is a key factor in the development of numerous pulmonary diseases. An international group of clinicians, radiologists and pathologists evaluated patients with previously identified idiopathic interstitial pneumonia (IIP) to determine unique features of cigarette smoking. Phase 1 (derivation group) identified smoking-related features in patients with a history of smoking (n=41). Phase 2 (validation group) determined if these features correctly predicted the smoking status of IIP patients (n=100) to participants blinded to smoking history. Finally, the investigators sought to determine if a new smoking-related interstitial lung disease phenotype could be defined. Phase 1 suggested that preserved forced vital capacity with disproportionately reduced diffusing capacity of the lung for carbon monoxide, and various radiographic and histopathological findings were smoking-related features. In phase 2, the kappa coefficient among clinicians was 0.16 (95% CI 0.11-0.21), among the pathologists 0.36 (95% CI 0.32-0.40) and among the radiologists 0.43 (95% CI 0.35-0.52) for smoking-related features. Eight of the 100 cases were felt to represent a potential smoking-related interstitial lung disease. Smoking-related features of interstitial lung disease were identified in a minority of smokers and were not specific for smoking. This study is limited by its retrospective design, the potential for recall bias in smoking history and lack of information on second-hand smoke exposure. Further research is needed to understand the relationship between smoking and interstitial lung disease.

Thoracic CT findings in Birt-Hogg-Dube syndrome.

OBJECTIVE: Birt-Hogg-Dubé syndrome manifests in the thorax as lung cysts. The purpose of this article is to describe the CT characteristics of cysts in patients with Birt-Hogg-Dubé syndrome and to note other thoracic findings. MATERIALS AND METHODS: The thoracic CT examinations of 17 patients with Birt-Hogg-Dubé syndrome were reviewed retrospectively for the presence, anatomic distribution (upper lung predominant, lower lung predominant, or diffuse), extent (size, number), and morphology (shape, wall thickness) of cysts. Any additional thoracic findings were also noted. RESULTS: The study population consisted of 13 women (76%) and four men (24%) with a mean age of 50.2 ±15.2 years. Two patients (12%) had normal findings on CT. Fifteen patients had cystic lung disease, all of whom had more than one cyst. Most patients had bilateral (13/15, 87%) and lower lung-predominant cysts (13/15, 87%). The cysts varied in size from 0.2 to 7.8 cm. The largest cysts were located in the lower lobes of 14 of 15 patients (93%). Of the nine patients with large cysts, most had at least one multiseptated cyst (7/9, 78%). Five of 15 patients (33%) had more than 20 cysts. Cyst shape varied among the 15 patients and also within individual patients (10/15, 67%) ranging from round to oval, lentiform, and multiseptated. Cysts showed no central or peripheral predominance. CONCLUSION: Discrete thin-walled cysts in patients with Birt-Hogg-Dubé syndrome are more numerous and larger in the lower lobes and vary in size and shape. Large lung cysts are frequently multiseptated. These features may aid in differentiating Birt-Hogg-Dubé syndrome from other more common cystic lung diseases.

Reference normal absolute and indexed values from ECG-gated MDCT: left atrial volume, function, and diameter.

OBJECTIVE: The purpose of this study was to retrospectively determine CT-based normal reference values of left atrial volume, function, and diameter normalized by age, sex, and body surface area. MATERIALS AND METHODS: The study group consisted of 74 subjects with normal findings at ECG-gated coronary CT angiography performed with retrospective gating. Analysis of left atrial volume (end-diastolic, end-systolic, and stroke volume) and function (ejection fraction) was performed with the Simpson method. Left atrial diameter was measured in the anteroposterior dimension. General linear model analysis was performed to model the data and assess statistical significance by age group after adjustment for sex and body surface area. RESULTS: The reference range for left atrial volume, function, and diameter was normalized (indexed) to age, sex, and body surface area in healthy subjects. A statistically significant difference was noted between left atrial volume and age without adjustment for sex and body surface area, but no statistically significant difference was found after adjustment for these variables. Sex and body surface area had a significant influence on left atrial volume, function, and diameter. CONCLUSION: Left atrial volume, function, and diameter normalized to age, sex, and body surface area can be reported from CTA datasets and may provide information important for patient care.

Clinical predictors of a diagnosis of idiopathic pulmonary fibrosis.

RATIONALE: Idiopathic pulmonary fibrosis (IPF) and other idiopathic interstitial pneumonias (IIPs) have similar clinical and radiographic features, but their histopathology, response to therapy, and natural history differ. A surgical lung biopsy is often required to distinguish between these entities. OBJECTIVES: We sought to determine if clinical variables could predict a histopathologic diagnosis of IPF in patients without honeycomb change on high-resolution computed tomography (HRCT). METHODS: Data from 97 patients with biopsy-proven IPF and 38 patients with other IIPs were examined. Logistic regression models were built to identify the clinical variables that predict histopathologic diagnosis of IPF. MEASUREMENTS AND MAIN RESULTS: Increasing age and average total HRCT interstitial score on HRCT scan of the chest may predict a biopsy confirmation of IPF. Sex, pulmonary function, presence of desaturation, or distance walked during a 6-minute walk test did not help discriminate pulmonary fibrosis from other IIPs. CONCLUSIONS: Clinical data may be used to predict a diagnosis of IPF over other IIPs. Validation of these data with a prospective study is needed.

The prognostic value of cardiopulmonary exercise testing in idiopathic pulmonary fibrosis.

RATIONALE: Idiopathic pulmonary fibrosis (IPF) is characterized by progressive dyspnea, impaired gas exchange, and ultimate mortality. OBJECTIVES: To test the hypothesis that maximal oxygen uptake during cardiopulmonary exercise testing at baseline and with short-term longitudinal measures would predict mortality in patients with idiopathic pulmonary fibrosis. METHODS: Data from 117 patients with IPF and longitudinal cardiopulmonary exercise tests were examined retrospectively. Survival was calculated from the date of the first cardiopulmonary exercise test. MEASUREMENTS AND MAIN RESULTS: Patients with baseline maximal oxygen uptake less than 8.3 ml/kg/min had an increased risk of death (n = 8; hazard ratio, 3.24; 95% confidence interval, 1.10-9.56; P = 0.03) after adjusting for age, gender, smoking status, baseline forced vital capacity, and baseline diffusion capacity for carbon monoxide. We were unable to define a unit change in maximal oxygen uptake that predicted survival in our cohort. CONCLUSIONS: We conclude that a threshold maximal oxygen uptake of 8.3 ml/kg/min during cardiopulmonary exercise testing at baseline adds prognostic information for patients with IPF.

Hypersensitivity Pneumonitis: Radiologic Phenotypes Are Associated With Distinct Survival Time and Pulmonary Function Trajectory.

BACKGROUND: Hypersensitivity pneumonitis (HP) is an interstitial lung disease with a better prognosis, on average, than idiopathic pulmonary fibrosis (IPF). We compare survival time and pulmonary function trajectory in patients with HP and IPF by radiologic phenotype. METHODS: HP (n = 117) was diagnosed if surgical/transbronchial lung biopsy, BAL, and exposure history results suggested this diagnosis. IPF (n = 152) was clinically and histopathologically diagnosed. All participants had a baseline high-resolution CT (HRCT) scan and FVC % predicted. Three thoracic radiologists documented radiologic features. Survival time is from HRCT scan to death or lung transplant. Cox proportional hazards models identify variables associated with survival time. Linear mixed models compare post-HRCT scan FVC % predicted trajectories. RESULTS: Subjects were grouped by clinical diagnosis and three mutually exclusive radiologic phenotypes: honeycomb present, non-honeycomb fibrosis (traction bronchiectasis and reticulation) present, and nonfibrotic. Nonfibrotic HP had the longest event-free median survival (> 14.73 years) and improving FVC % predicted (1.92%; 95% CI, 0.49-3.35; P = .009). HP with non-honeycomb fibrosis had longer survival than IPF (> 7.95 vs 5.20 years), and both groups experienced a significant decline in FVC % predicted. Subjects with HP and IPF with honeycombing had poor survival (2.76 and 2.81 years, respectively) and significant decline in FVC % predicted. CONCLUSIONS: Three prognostically distinct, radiologically defined phenotypes are identified among patients with HP. The importance of pursuing a specific diagnosis (eg, HP vs IPF) among patients with non-honeycomb fibrosis is highlighted. When radiologic honeycombing is present, invasive diagnostic testing directed at determining the diagnosis may be of limited value given a uniformly poor prognosis.

Accuracy of high-resolution CT in the diagnosis of diffuse lung disease: effect of predominance and distribution of findings.

OBJECTIVE: The purpose of this study was to determine whether the predominant findings at high-resolution CT influence the accuracy of diagnosis of diffuse lung disease. MATERIALS AND METHODS: The cases of 100 patients with diffuse lung disease who underwent high-resolution CT and tissue diagnosis were studied. Three thoracic radiologists reviewed high-resolution CT images blindly and independently for patterns of abnormality, listing their three main diagnoses and level of confidence in the first choice. The effect of the findings on accuracy was analyzed. RESULTS: For honeycombing, the accuracy of the main diagnosis was 96.6%, 92.2%, and 92.3% for the three readers, and that of the three main diagnoses was 96.6%, 96.1%, and 92.3%. For cysts, the accuracy of the main diagnosis was 88.9%, 80%, and 81.8% and of the three main diagnoses was 100%, 90%, and 90.9%. For bronchovascular thickening, the accuracy of the main diagnosis was 91.7%, 87.5%, and 90.9% and of the three main diagnoses was 91.7%, 100%, and 90.9%. For ground-glass opacification (GGO), the accuracy of the main diagnosis was 75.5%, 55%, and 44.2% and of the three main diagnoses was 89.8%, 75%, and 65.4%. Only combining honeycombing with GGO improved the accuracy of GGO. Anatomic craniocaudal distribution improved reader accuracy when GGO was predominantly present in the lower part of the lung. Interobserver agreement on the presence of major findings was a mean kappa value of 0.45 for honeycombing, 0.74 for lung cysts, 0.63 for bronchovascular thickening, and 0.56 for GGO. Agreement for the craniocaudal distribution of major findings was a mean kappa value of 0.48 for honeycombing, 0.52 for bronchovascular thickening, and 0.32 for GGO. CONCLUSION: The predominant findings of honeycombing and bronchovascular thickening are associated with more than 90% accuracy in the first-choice diagnosis of diffuse lung disease; the finding of lung cysts has 80-89% accuracy. GGO as a predominant pattern had unreliable accuracy, but the accuracy improved when GGO was combined with either honeycombing or lower-lung distribution.

Smoking-related interstitial lung disease: radiologic-clinical-pathologic correlation.

Cigarette smoking is a recognized risk factor for development of interstitial lung disease (ILD). There is strong evidence supporting a causal role for cigarette smoking in development of respiratory bronchiolitis ILD (RB-ILD), desquamative interstitial pneumonitis (DIP), and pulmonary Langerhans cell histiocytosis (PLCH). In addition, former and current smokers may be at increased risk for developing idiopathic pulmonary fibrosis (IPF). The combination of lower lung fibrosis and upper lung emphysema is being increasingly recognized as a distinct clinical entity in smokers. High-resolution computed tomography is sensitive for detection and characterization of ILD and may allow recognition and classification of the smoking-related ILDs (SR-ILDs) into distinct individual entities. However, the clinical, radiologic, and histologic features overlap among the different SR-ILDs, and mixed patterns of disease frequently coexist in the same patient. The overlap is most significant between RB-ILD and DIP. Macrophage accumulation is bronchiolocentric in RB-ILD, producing centrilobular ground-glass opacity, and more diffuse in DIP, producing widespread ground-glass changes. The coexistence of upper lung nodules and cysts in a smoker allows confident diagnosis of PLCH. Final diagnosis of an SR-ILD and identification of the specific entity can be achieved with certainty only after the pulmonologist, radiologist, and pathologist have reviewed all of the clinical, radiologic, and pathologic data.

Reliability of MDCT in characterizing pulmonary venous drainage, diameter and distance to first bifurcation: an interobserver study.

RATIONALE AND OBJECTIVES: To evaluate the interobserver agreement of readers in evaluating pulmonary venous anatomy and in measuring pulmonary vein ostial diameters and distance to first bifurcation. MATERIALS AND METHODS: This study was approved by our institutional review board. Thin-section contrast material-enhanced multidetector computed tomography examinations of the thorax were retrospectively reviewed in 200 consecutive patients (38 females and 162 males), age 24-79 years (mean, 52.8) referred for imaging before radiofrequency ablation therapy for atrial fibrillation. For each patient, pulmonary venous anatomy and drainage patterns including the number of venous ostia was assessed independently by experienced cardiothoracic radiologists. Pulmonary vein ostial diameter and distance to the first bifurcation of the four major pulmonary veins (right inferior and superior, left inferior and superior), the middle lobe pulmonary vein, and any anomalous pulmonary veins (common trunks and accessory veins) were measured independently at a workstation. Interreader assessment of pulmonary venous anatomy was evaluated using the Kappa statistic. Interreader variation in measurements of venous diameter and distant to first bifurcation were estimated by Bland-Altman plots and Pitman's test of difference in variance. RESULTS: Very good to excellent interreader agreement in detection of anomalous pulmonary venous anatomy, middle lobe pulmonary venous drainage, and other thoracic venous anomalies. No significant variation between readers in pulmonary vein ostial diameter measurements for the four major and middle lobe pulmonary veins, or the anomalous pulmonary veins. Significant interreader variability was noted in measurements of the pulmonary vein distance to first bifurcation for the right inferior (P = .017), middle lobe (P = .005), and left inferior (P = .015) pulmonary veins. CONCLUSIONS: There is excellent interobserver agreement when evaluating normal and anomalous pulmonary venous drainage patterns, and when measuring normal or anomalous pulmonary vein diameters. However, measurements of distances to first bifurcation were less reliable across readers.

Normative analysis of pulmonary vein drainage patterns on multidetector CT with measurements of pulmonary vein ostial diameter and distance to first bifurcation.

RATIONALE AND OBJECTIVES: To document the frequency of normal and anomalous drainage patterns of the pulmonary veins, and to establish normal values for pulmonary vein ostial diameters, and distance to first bifurcation using multidetector computed tomography, as pertinent to ablation procedures for atrial fibrillation. MATERIALS AND METHODS: Two cardiothoracic radiologists retrospectively reviewed thin-section contrast material-enhanced multidetector computed tomography examinations of the thorax in 200 consecutive patients (38 females and 162 males), age 24-79 years (mean 52.8) referred for imaging before radiofrequency ablation therapy for atrial fibrillation. Pulmonary vein anatomy was based on both the number of venous ostia and the drainage patterns of pulmonary veins. Pulmonary vein ostial diameters and distance to first bifurcation of the four major pulmonary veins (right inferior and superior, left inferior and superior) and any additional pulmonary veins were measured at a workstation using both axial images and multiplanar reconstructions by two experienced cardiothoracic radiologists; the mean pulmonary vein diameter and the shortest distance to first bifurcation of the two measurements are reported. RESULTS: The majority of patients, 82% (164 patients) had four pulmonary veins, with a superior and inferior ostium on the right and a superior and inferior ostium on the left. Of the remainder, 9% (18 patients) had five veins, 4.5% (9 patients) had three veins, 3% (6 patients) had two anomalies each, and 0.5% (1 patient) had three anomalies. The middle lobe pulmonary vein drained into the right superior pulmonary vein in 83.5% of patients, directly into the left atrium in 11% of patients, and into the right inferior pulmonary vein in 5.5% of patients; 6.5% of patients had a single left pulmonary vein ostium. Mean pulmonary vein diameters with 95% confidence intervals at the ostia were as follows: right superior 17.6 (13.64-15.36) mm; left superior 16.6 (16.03-17.08) mm; right inferior 17.1 (16.58-17.55) mm; left inferior 14.8 (14.25-15.27) mm, and independent middle lobe 8.6 (8.27-8.86) mm. Mean distance to first bifurcation with 95% confidence intervals were: right superior 14.5 (17.02-18.23) mm; left superior 17.6 (16.63-18.53) mm; right inferior 7.0 (6.49-7.46) mm; left inferior 13.5 (12.83-14.16) mm, and independent middle lobe 8.4 (7.7-9.17) mm. CONCLUSION: Thin-section thoracic computed tomography demonstrates a greater variability of pulmonary venous drainage than previously described. There is greater variability of the right lung venous drainage compared to the left lung. Eighty-two percent of people have four standard pulmonary veins. There is significant variability in pulmonary vein diameter and distance to first bifurcation.

Intrathoracic Fat Measurements Using Multidetector Computed Tomography (MDCT): Feasibility and Reproducibility.

Intrathoracic fat volume, more specifically, epicardial fat volume, is an emerging imaging biomarker of adverse cardiovascular events. The purpose of this work is to show the feasibility and reproducibility of intrathoracic fat volume measurement applied to contrast-enhanced multidetector computed tomography images. A retrospective cohort study of 62 subjects free of cardiovascular disease (55% females, age = 49 ± 11 years) conducted from 2008 to 2011 formed the study group. Intrathoracic fat volume was defined as all fat voxels measuring -50 to -250 Hounsfield Unit within the intrathoracic cavity from the level of the pulmonary artery bifurcation to the heart apex. The intrathoracic fat was separated into epicardial and extrapericardial fat by tracing the pericardium. The measurements were obtained by 2 readers and compared for interrater reproducibility. The fat volume measurements for the study group were 141 ± 72 cm3 for intrathoracic fat, 58 ± 27 cm3 for epicardial fat, and 84 ± 50 cm3 for extrapericardial fat. There was no statistically significant difference in intrathoracic fat volume measurements between the 2 readers, with correlation coefficients of 0.88 (P = .55) for intrathoracic fat volume and -0.12 (P = .33) for epicardial fat volume. Voxel-based measurement of intrathoracic fat, including the separation into epicardial and extrapericardial fat, is feasible and highly reproducible from multidetector computed tomography scans.

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.

Thoracic lymph node enlargement in usual interstitial pneumonitis and nonspecific-interstitial pneumonitis: prevalence, correlation with disease activity and temporal evolution.

PURPOSE: To evaluate the prevalence of thoracic lymph node enlargement (LNE) in usual (UIP) and nonspecific (NSIP) interstitial pneumonitis, change in LNE over time, and if LNE is related to disease activity. METHODS AND MATERIALS: High-resolution CT scans (HRCT) in 20 patients each with UIP and NSIP were retrospectively reviewed. Two HRCT scans were reviewed for each patient, at diagnosis and a mean of 1 +/- 0.7 years later. Two thoracic radiologists independently recorded the location and size of thoracic lymph nodes (LNs) > 10-mm in short-axis diameter, using the American Thoracic Society lymph node mapping scheme. HRCT disease severity was scored for ground glass opacity and fibrosis. The number and size of enlarged LN stations were compared with HRCT scores. RESULTS: LNE was found on 44 HRCT examinations (21 baseline prevalence 52.5%, 23 follow-up, prevalence 57.5%), most common in the low right paratracheal (38%) and subcarinal (36%) regions. There was no significant difference in LN size or number of enlarged LN stations between baseline and follow-up CT. LNE prevalence was not different on baseline CT (P = 0.34) follow-up CT (P = 0.11) between UIP and NSIP patients. The mean size of the largest enlarged LN was 1.36 cm (1 to 2.1 cm) at baseline and 1.43 cm (1 to 1.9 cm) on follow-up CT. Mean CT ground glass and fibrosis scores were 1.98 and 1.6 when LNE was present, and 1.34 and 1.03 when absent (P = 0.008 and 0.003, respectively). The number and maximum size of enlarged LNs did not correlate with CT ground glass or fibrosis scores. Five patients who developed LNE between baseline and follow-up CT examinations had a greater increase in CT fibrosis scores than patients whose LNE status did not change (P = 0.004); CT ground glass scores were not significantly different. There was a trend for UIP patients to progress from absence of LNE to presence of LNE (4/20 patients or 20%). CONCLUSIONS: Intrathoracic LNE is common in both UIP and NSIP, and becomes increasingly prevalent in UIP patients over time. LNE is more prevalent with more severe lung disease. An increase in LNE over time is associated with the progression of fibrosis, and should not raise concern for co-existing infection or malignancy, in the absence of other clinical findings that would suggest this.

Long-term changes in circulating CD4 T lymphocytes in virologically suppressed patients after 6 years of highly active antiretroviral therapy.

Highly active antiretroviral therapy (HAART) initiated in advanced HIV disease is associated with CD4 lymphocyte increases (200-300 cells/mm3 after 2-4 years), although longer-term cellular dynamics have not been studied. We observed a significant median CD4 lymphocyte increase of 126 cells/mm3 and 54 naive CD4 lymphocytes from year 3 to 6 of HAART among 20 individuals with pre-HAART CD4 cell counts of 100-300 cells/mm3. This cohort represents the longest prospective immunological follow-up of virologically suppressed patients on HAART.

Radiologic findings are strongly associated with a pathologic diagnosis of usual interstitial pneumonia.

PURPOSE: To determine which clinical and radiologic findings are independently associated with a pathologic diagnosis of usual interstitial pneumonia (UIP). METHODS: We recently reported, using a prospective, multicenter study of patients suspected of having idiopathic interstitial pneumonia (IIP), that a confident diagnosis of UIP made by experienced radiologists was correct in 95% of cases. In the current article, we further analyzed data from this study. Ninety-one patients were entered into the study. Clinical, physiologic, chest radiographic, and CT features were prospectively recorded, and analyzed using univariate and multivariate logistic regression analysis to compare the patients with a histologic diagnosis of UIP with those who received other pathologic diagnoses. RESULTS: Fifty-four of 91 patients (59%) received a pathologic diagnosis of UIP. The following features recorded at the referring clinical centers were associated with a pathologic diagnosis of UIP on multivariate analysis: lower-lobe honeycombing on high-resolution CT (HRCT) [odds ratio, 11.45], radiographic findings consistent with UIP (odds ratio, 5.73), elevated ratio of FEV(1) to FVC (odds ratio, 4.8), and absence of smoking history (odds ratio, 0.19). On multivariate analysis of specific HRCT features recorded by four experienced chest radiologists, lower-lung honeycombing (odds ratio, 5.36) and upper-lung irregular lines (odds ratio, 6.28) were the only independent predictors of UIP. Using only these two factors, a diagnosis of UIP could be established with a sensitivity of 74%, a specificity of 81%, and a positive predictive value of 85%. CONCLUSION: In patients presenting with a clinical syndrome suggestive of IIP, CT findings of lower-lung honeycombing and upper-lung irregular lines are most closely associated with a pathologic diagnosis of UIP.

Does medical school performance predict radiology resident performance?

RATIONALE AND OBJECTIVES: The authors performed this study to examine the relationship, if any, of a large number of measures of medical school performance with radiology residency performance. MATERIALS AND METHODS: Applications of 77 radiology residents enrolled from 1991 to 2000 were reviewed. Medical school grades, dean's letter summary statements, letters of recommendation, selection to Alpha Omega Alpha (AOA), and National Board of Medical Examiners (NBME) and U.S. Medical Licensing Examination (USMLE) Step 1 scores were recorded. Student t tests, analysis of variance, and correlation coefficients were used to examine the relationship between these measures of medical school performance and subsequent performance during radiology residency as determined by rotation evaluations, retrospective faculty recall scores, and American College of Radiology (ACR) and American Board of Radiology (ABR) examination scores. Resident performance was also correlated with prestige of the medical school attended. RESULTS: Preclinical grades of Honors or A; clinical grades of Honors or A in medicine, surgery, and pediatrics; and high NBME/USMLE scores strongly predicted success on the ABR written clinical examination but did not predict rotation performance. Most other measures of medical school performance, including outstanding Dean's letters and letters of recommendation, AOA selection during the senior year, and high medical school prestige did not predict high examination scores or superior rotation performance during residency. CONCLUSION: Success on the ABR examination can be predicted by medical school success in preclinical courses, some clinical courses, and USMLE examination scores. Dean's letters, letters of recommendation, AOA selection during the senior year, and medical school prestige do not appear to predict future resident performance as reliably.

Left atrial function and maximum volume as determined by MDCT are independently associated with atrial fibrillation.

RATIONALE AND OBJECTIVES: To assess whether left atrial (LA) volume, function, and diameter as determined by multidetector computed tomography (MDCT) are associated with the presence and chronicity of atrial fibrillation (AF). MATERIALS AND METHODS: A total of 232 subjects, 156 with AF (43 with chronic and 113 with paroxysmal) and 76 normal subjects, formed the study population. AF subjects underwent MDCT of the pulmonary veins and LA, and normal subjects underwent coronary computed tomography (CT), on which LA volume, function, and diameter were measured. Associations between each MDCT LA parameter and presence and chronicity of AF were assessed using logistic regression analysis. RESULTS: The indexed LA maximum volume (odds ratio [OR]=2.42; 95% confidence interval [CI], 1.43-4.08; P=.0009) was significantly associated with chronicity and presence of AF (OR=1.06; 95% CI, 1.03-1.10; P=.0003) after adjustment for traditional risk factors. The LA function was associated with presence of AF (OR=0.93; 95% CI, 0.89-0.97; P=.0005), but not with AF chronicity (OR=1.12; 95% CI, 0.93-1.33; P=.21). CONCLUSIONS: Decreased LA function is associated with presence of AF, and increased LA maximum volume is associated with presence and chronicity of AF, independent of traditional risk factors.

Reference absolute and indexed values for left and right ventricular volume, function and mass from cardiac computed tomography.

INTRODUCTION: Left ventricular (LV) and right ventricular (RV) volumetric and functional parameters are important biomarkers for morbidity and mortality in patients with heart failure. PURPOSE: To retrospectively determine reference mean values of LV and RV volume, function and mass normalised by age, gender and body surface area (BSA) from retrospectively electrocardiographically gated 64-slice cardiac computed tomography (CCT) by using automated analysis software in healthy adults. MATERIALS AND METHODS: The study was approved by the institutional review board with a waiver of informed consent. Seventy-four healthy subjects (49% female, mean age 49.6 ± 11) free of hypertension and hypercholesterolaemia with a normal CCT formed the study population. Analyses of LV and RV volume (end-diastolic, end-systolic and stroke volumes), function (ejection fraction), LV mass and inter-rater reproducibility were performed with commercially available analysis software capable of automated contour detection. General linear model analysis was performed to assess statistical significance by age group after adjustment for gender and BSA. Bland-Altman analysis assessed the inter-rater agreement. RESULTS: The reference range for LV and RV volume, function, and LV mass was normalised to age, gender and BSA. Statistically significant differences were noted between genders in both LV mass and RV volume (P-value < 0.0001). Age, in concert with gender, was associated with significant differences in RV end-diastolic volume and LV ejection fraction (P-values 0.027 and 0.03). Bland-Altman analysis showed acceptable limits of agreement (±1.5% for ejection fraction) without systematic error. CONCLUSION: LV and RV volume, function and mass normalised to age, gender and BSA can be reported from CCT datasets, providing additional information important for patient management.