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.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109344/1/jmiro12186.pd

CT evaluation of the equivocal pulmonary nodule

In the setting of a questionable pulmonary nodule demonstrated by conventional radiographs, the place of CT in the diagnostic algorithm is not well established. We reviewed our experience in 50 consecutive patients referred to CT for a "possible pulmonary nodule." From the chest radiographs we noted nodule location, maximum dimension, presence on one or both views, and presence on a previous radiograph (&gt; 1 year old), and nodules were categorized as "likely" or "unlikely" to be real parenchymal lesions based on radiographic appearance. Of a total of 56 questionable nodules, CT demonstrated no abnormality in 21 cases, parenchymal nodules in 16, scarring, atelectasis, or infiltrate in 11, and normal structural variants in 8. True pulmonary nodules were statistically significantly more frequently categorized as "likely" lesions than normal variants or no disease, but this was not of a magnitude to be clinically useful. Based on analysis of various radiographic features of equivocal nodules and their subsequent outcomes, we suggest a radiologic approach to the equivocal pulmonary nodule.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26780/1/0000336.pd

Density of states determined from Monte Carlo simulations

We describe method for calculating the density of states by combining several canonical monte carlo runs. We discuss how critical properties reveal themselves in $g(\epsilon)$ and demonstrate this by applying the method several different phase transitions. We also demonstrate how this can used to calculate the conformal charge, where the dominating numerical method has traditionally been transfer matrix.Comment: Major revision of paper, several references added throughout. Current version accepted for publication in Phys. Rev.

Idiopathic pulmonary fibrosis: Prognostic value of changes in physiology and six minute hallwalk.

Rationale and Hypothesis: Idiopathic pulmonary fibrosis is a fatal disease with a variable rate of progression. We hypothesized that changes in distance walked and quantity of desaturation during a six-minute-walk test (6MWT) would add prognostic information to changes in FVC or diffusing capacity for carbon monoxide. Methods: One hundred ninety-seven patients with idiopathic pulmonary fibrosis were evaluated. Desaturation during the 6MWT was associated with increased mortality even if a threshold of 88% was not reached. Baseline walk distance predicted subsequent walk distance but was not a reliable predictor of subsequent mortality in multivariate survival models. The predictive ability of serial changes in physiology varied when patients were stratified by the presence/absence of desaturation 88% during a baseline 6MWT. For patients with a baseline saturation 88% during a 6MWT, the strongest observed predictor of mortality was serial change in diffusing capacity for carbon monoxide. For patients with saturation 88% during their baseline walk test, serial decreases in FVC and increases in desaturation area significantly predicted subsequent mortality, whereas decreases in walk distance and in diffusing capacity for carbon monoxide displayed less consistent statistical evidence of increasing mortality in our patients. Conclusion: These data highlight the importance of stratifying patients by degree of desaturation during a 6MWT before attributing prognostic value to serial changes in other physiologic variables.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91940/1/2006 AJRCCM Idiopathic pulmonary fibrosis - Prognostic value of changes in physiology and six minute hallwalk.pd

Prognostic implications of physiologic and radiographic changes in idiopathic interstitial pneumonia

Idiopathic interstitial pneumonias are a diverse group of lung diseases with varied prognoses. We hypothesized that changes in physiologic and radiographic parameters would predict survival. We retrospectively examined 80 patients with usual interstitial pneumonia and 29 patients with nonspecific interstitial pneumonia. Baseline characteristics were examined together with 6-month change in forced vital capacity, diffusing capacity for carbon monoxide, and ground glass infiltrate and fibrosis on high resolution computed tomography. Patients with usual interstitial pneumonia were more likely to have a statistically significant or marginally significant decline in lung volume, diffusing capacity for carbon monoxide, and an increase in ground glass infiltrates (p <= 0.08) compared with patients with nonspecific interstitial pneumonia. For patients with usual interstitial pneumonia, change in forced vital capacity was the best physiologic predictor of mortality (p = 0.05). In a multivariate Cox proportional hazards model controlling for histopathologic diagnosis, gender, smoking history, baseline forced vital capacity, and 6-month change in forced vital capacity, a decrease in forced vital capacity remained an independent risk factor for mortality (decrease > 10%; hazard ratio 2.47; 95% confidence interval 1.29, 4.73; p = 0.006). We conclude that a 6-month change in forced vital capacity gives additional prognostic information to baseline features for patients with idiopathic interstitial pneumonia.Supported by National Institutes of Health NHLBI grants P50HL46487, NIH/NCRR 3 MO1 RR00042-33S3, NIH/NIA P60 AG08808-06, NHLBI, 1 K24 HL04212, and 1 K23 HL68713.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91973/1/2003 AJRCCM - Prognostic Implications of Physiologic and Radiographic Changes in Idiopathic Interstitial Pneumonia.pd

CT evaluation of mediastinal masses

CT is an important modality for imaging mediastinal masses, and certain CT attenuation features (fat, calcium, or water attenuation, contrast enhancement) are well known to suggest specific diagnoses. In a series of 132 consecutive patients with tissue-proven mediastinal masses, these specific CT features were present in only 16. We evaluated the ability of CT to differentiate soft tissue mediastinal masses based on morphology and distribution of disease. Metastatic disease and lymphoma accounted for 69% of masses in this series, and CT could not generally differentiate them. However, CT was helpful in differential diagnosis in certain settings. CT demonstration of multiple mediastinal masses when conventional radiographs showed a single mass generally excluded diagnoses such as thymoma and teratoma. CT demonstration of a single middle mediastinal mass, frequently missed by conventional radiography, made metastatic disease a much more likely diagnosis than lymphoma. Finally, CT demonstration of certain ancillary findings strongly favored a diagnosis of lymphoma (axillary adenopathy) or metastatic disease (solitary pulmonary mass, focal liver lesions, bone lesions).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26707/1/0000257.pd

Prognostic value of desaturation during a six minute walk test in Idiopathic Interstitial Pneumonia

Exercise-induced hypoxia is an index of the severity of interstitial lung disease. We hypothesized that desaturation during a 6-minute walk test would predict mortality for patients with usual interstitial pneumonia (n = 83) and nonspecific interstitial pneumonia (n = 22). Consecutive patients with biopsy-proven disease performed a 6-minute walk test between January 1996 and December 2001. Desaturation was defined as a fall in oxygen saturation to 88% or less during the 6-minute walk test. Desaturation was common (44 of 83 usual interstitial pneumonia and 8 of 22 nonspecific interstitial pneumonia; chi square, p = 0.39). Patients with usual interstitial pneumonia or nonspecific interstitial pneumonia who desaturated had a significantly higher mortality than patients who did not desaturate (respective log-rank tests, p = 0.0018, p = 0.0089). In patients with usual interstitial pneumonia, the presence of desaturation was associated with an increased hazard of death (hazard ratio, 4.2; 95% confidence interval, 1.40, 12.56; p = 0.01) after adjusting for age, sex, smoking, baseline diffusion capacity for carbon monoxide, FVC, and resting saturation.Weconclude that knowledge of desaturation during a 6-minute walk test adds prognostic information for patients with usual interstitial pneumonia and nonspecific interstitial pneumonia.Supported in part by National Institutes of Health NHLBI Grant #P50HL46487, NHLBI, 1 K24 HL04212, and 1 K23 HL68713.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91972/1/2003 AJRCCM - Prognostic value of desaturation during a six minute walk test in Idiopathic Interstitial Pneumonia.pd

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.Supported by National Institute of Health NHLBI grant P50HL-56402, NHLBI, 2 K24 HL04212, 1 K23 HL68713, and 1K23 HL077719. C.D.F. was supported by the Alberta Heritage Foundation for Medical Research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91965/1/2009 AJRCCM The prognostic value of Cardiopulmonary Exercise Testing in Idiopathic Pulmonary Fibrosis.pd

Fibroblastic Foci in Usual Interstitial Pneumonia: Idiopathic versus Collagen Vascular Disease

A histologic feature of usual interstitial pneumonia is the presence of fibroblastic foci. As some patients with usual interstitial pneumonia and an underlying collagen vascular disease have a better prognosis, we hypothesized that they would have fewer fibroblastic foci. Pathologists reviewed surgical lung biopsies from 108 patients with usual interstitial pneumonia (nine with collagen vascular disease) and assigned a score (absent 0, mild 1, moderate 2, and marked 3) for fibroblastic foci. Patients with idiopathic usual interstitial pneumonia had a higher median profusion of fibroblastic foci (1.75 vs. 1.0, p = 0.003). Baseline characteristics were similar, although patients with a collagen vascular disease were younger, had a shorter duration of symptoms, and had a higher percentage of predicted total lung capacity. Profusion of fibroblastic foci was the most discriminative feature for separating idiopathic from collagen vascular disease–associated usual interstitial pneumonia (odds ratio 8.31; 95% confidence interval, 1.98, 59.42; p = 0.002 for a one-unit increase in fibroblastic foci score). No deaths were noted in the collagen vascular disease–associated usual interstitial pneumonia group; 52 deaths occurred in the idiopathic usual interstitial pneumonia group (log rank; p = 0.005). We conclude that patients with collagen vascular disease–associated usual interstitial pneumonia have fewer fibroblastic foci and improved survival.Supported in part by National Institutes of Health National Heart, Lung, and Blood Institute grant #P50HL46487, NIH/NCRR 3 MO1 RR00042–33S3, NIH/NIA P60 AG08808–06, NHLBI 1 K24 HL04212, and 1 K23 HL68713.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91974/1/2003 AJRCCM - Fibroblastic Foci in Usual Interstitial Pneumonia -Idiopathic versus Collagen Vascular Disease.pd

Sex differences in physiological progression of idiopathic pulmonary fibrosis

In idiopathic pulmonary fibrosis, incidence is higher in males, and females may have better survival. The aim of the present study was to determine whether the rate of increase in desaturation during serial 6-min walk testing would be greater, and survival worse, for males versus females. Serial changes in the percentage of maximum desaturation area (DA) over 1 yr were estimated using mixed models in 215 patients. DA was defined as the total area above the curve created using desaturation percentage values observed during each minute of the 6-min walk test. Multivariate Cox regression assessed survival differences. Adjusting for baseline DA, 6-min walk distance, change in 6-min walk distance over time and smoking history, the percentage of maximum DA increased by an average of 2.83 and 1.37% per month for males and females, respectively. Females demonstrated better survival overall, which was more pronounced in patients who did not desaturate below 88% on ambulation at baseline and after additionally adjusting for 6-month relative changes in DA and forced vital capacity. These data suggest that differences in disease progression contribute to, but do not completely explain, better survival of females with idiopathic pulmonary fibrosis.This work was supported by National Institutes of Health grants 5P50HL56402, U10HL080371, 2K24HL04212, K12RR024987 and K23HL68713, and the Alberta Heritage Medical Foundation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91966/1/2008 ERJ - Sex Differences in Physiologic Progression of Idiopathic Pulmonary Fibrosis.pd