Evaluation of Image Quality for 7 Iterative Reconstruction Algorithms in Chest Computed Tomography Imaging: A Phantom Study.

OBJECTIVES: This study aimed to evaluate the image quality of 7 iterative reconstruction (IR) algorithms in comparison to filtered back-projection (FBP) algorithm. METHODS: An anthropomorphic chest phantom was scanned on 4 computed tomography scanners and reconstructed with FBP and IR algorithms. Image quality of anatomical details-large/medium-sized pulmonary vessels, small pulmonary vessels, thoracic wall, and small and large lesions-was scored. Furthermore, general impression of noise, image contrast, and artifacts were evaluated. Visual grading regression was used to analyze the data. Standard deviations were measured, and the noise power spectrum was calculated. RESULTS: Iterative reconstruction algorithms showed significantly better results when compared with FBP for these criteria (regression coefficients/P values in parentheses): vessels (FIRST: -1.8/0.05, AIDR Enhanced: <-2.3/0.01, Veo: <-0.1/0.03, ADMIRE: <-2.1/0.04), lesions (FIRST: <-2.6/0.01, AIDR Enhanced: <-1.9/0.03, IMR1: <-2.7/0.01, Veo: <-2.4/0.02, ADMIRE: -2.3/0.02), image noise (FIRST: <-3.2/0.004, AIDR Enhanced: <-3.5/0.002, IMR1: <-6.1/0.001, iDose: <-2.3/0.02, Veo: <-3.4/0.002, ADMIRE: <-3.5/0.02), image contrast (FIRST: -2.3/0.01, AIDR Enhanced: -2.5/0.01, IMR1: -3.7/0.001, iDose: -2.1/0.02), and artifacts (FIRST: <-3.8/0.004, AIDR Enhanced: <-2.7/0.02, IMR1: <-2.6/0.02, iDose: -2.1/0.04, Veo: -2.6/0.02). The iDose algorithm was the only IR algorithm that maintained the noise frequencies. CONCLUSIONS: Iterative reconstruction algorithms performed differently on all evaluated criteria, showing the importance of careful implementation of algorithms for diagnostic purposes.

Progression and mortality of interstitial lung disease in mixed connective tissue disease: a long-term observational nationwide cohort study.

Objectives: To assess the prevalence, extent, progression, functional impact and mortality of interstitial lung disease (ILD) in a nationwide unselected MCTD cohort. Methods: The study cohort included patients with high-resolution CT lung scans available at baseline (n = 135) and at follow-up (n = 119). The extent of disease was expressed as percentage of total lung volume (TLV). Results: ILD was present in 41% of MCTD patients at follow-up. Median (interquartile) extent (% of TLV) was 5 (8) at baseline and 7 (17) at follow-up, mean length 6.4 years later. The lung disease progressed in 19% of patients across the observation period. Predictors of ILD progression were elevated anti-RNP titre [hazard ratio (HR) 1.5, 95% CI: 1.1, 2.0; P = 0.008], presence of anti-ro52 antibodies (HR = 3.5, 95% CI: 1.2, 10.2; P = 0.023), absence of arthritis (HR = 0.2, 95% CI: 0.1, 0.6; P = 0.004) and male gender (HR = 4.0, 95% CI: 1.4, 11.5; P = 0.011) after age and baseline disease adjustments. The risk of death increased by 2.9 (95% CI: 1.1, 7.9; P = 0.038) in patients where disease involved ⩾5% of TLV. Conclusion: Lung disease extent and progression in MCTD are modest. Yet, the extension continues several years after MCTD diagnosis causing lung function decline and increasing the risk of mortality. The study identified male gender, elevated anti-RNP titre, presence of anti-ro52 antibodies and absence of arthritis as the strongest predictors of ILD progression.

Lung disease, T-cells and inflammation in common variable immunodeficiency disorders.

INTRODUCTION: Besides hypogammaglobulinemia and recurrent infections, abnormalities of T-cells might contribute to lung damage in common variable immunodeficiency disorders (CVID). MATERIALS AND METHODS: In 16 adult patients, the majority of whom had pulmonary abnormalities, we studied T-cell subsets and markers of inflammation in bronchoalveolar lavage fluid (BALF) and blood and their relations with pulmonary function and high resolution computed tomography (HRCT). RESULTS: We demonstrated that some of the lymphocyte abnormalities previously demonstrated in peripheral blood from CVID patients, such as low CD4/CD8 T-cell ratio, were also present in BALF. Moreover, low BALF CD4/CD8 ratio (≤ 1), found in seven patients, was significantly associated with higher blood CD8⁺ cell count and to lower values of the lung function variables; forced expiratory volume (FVC), total lung capacity (TLC), vital capacity (VC) and residual volume (RV) in % of predicted. The expression of the inflammatory markers HLA-DR and CCR5 on T-cells was significantly higher, and the expression of CCR7 significantly lower, in BALF compared to blood, possibly reflecting an inflammatory/cytotoxic T-cell phenotype within pulmonary tissue in CVID. Furthermore, patients with bronchiectasis had higher concentrations of the pro-inflammatory cytokine TNFα in plasma, compared to those without. CONCLUSION: Our findings suggest that inflammation and T-cell activation may be involved in the immunopathogenesis of pulmonary complications in CVID.

Prevalence and severity of interstitial lung disease in mixed connective tissue disease: a nationwide, cross-sectional study.

BACKGROUND: Mixed connective tissue disease (MCTD) is an immune-mediated, systemic disorder of unknown cause. OBJECTIVE: To assess the prevalence, pattern and severity of interstitial lung disease (ILD) in a cross-sectional study of the nationwide, Norwegian MCTD cohort. METHODS: 126 patients with MCTD were systematically examined for ILD by high-resolution CT (HRCT), pulmonary function tests (PFT), 6 min walk test (6MWT) and by the New York Heart Association (NYHA) functional classification of dyspnoea. The extent and type of HRCT lung abnormalities were scored according to the CT criteria of ILD recommended by the Fleischner Society. RESULTS: All 126 patients were Caucasian, 75% women. At the time of the cross-sectional ILD study, the patients had a mean disease duration of 9.0 years. 52% of the patients had abnormal HRCT findings, most commonly reticular patterns consistent with lung fibrosis (35%). Lung fibrosis was quantified as minor in 7%, moderate in 9% and severe in 19% of the patients. Fibrosis was uniformly concentrated in the lower parts of the lungs and was not associated with smoking. Patients with severe lung fibrosis had lower PFT values, shorter 6MWT and a higher mean NYHA functional class. After a mean 4.2 years' follow-up, overall mortality was 7.9%. Mortality in patients with normal HRCT was 3.3%, as compared with 20.8% in patients with severe lung fibrosis (p<0.01). CONCLUSIONS: Severe lung fibrosis is common in MCTD, has an impact on pulmonary function and overall physical capacity and is associated with increased mortality.

Diagnostic accuracy of computed tomography and histopathology in the diagnosis of usual interstitial pneumonia.

BACKGROUND: The relative clinical benefit of histopathology and computed tomography (CT) in patients with idiopathic interstitial pneumonia (IIP) is under debate. PURPOSE: To analyze thin-section CT features and histopathologic findings in patients with usual interstitial pneumonia (UIP) in the clinical context of idiopathic pulmonary fibrosis (IPF), and to evaluate and compare diagnostic accuracy of the two methods among patients with an appropriate spectrum of IIP. MATERIAL AND METHODS: The study included 91 patients (49 men; mean age 53.2 years; median follow-up 7.2 years) with clinically suspected interstitial lung disease. All underwent surgical lung biopsy and thin-section CT. Two independent readers retrospectively assessed the CT images for the extent and pattern of abnormality and made a first-choice diagnosis. Two pathologists retrospectively assessed the histopathologic slides. In 64 patients with IIP, a retrospective composite reference standard identified 41 patients with UIP. CT characteristics of UIP and IIPs other than UIP were compared with univariate and multivariate analyses. RESULTS: There was good agreement between the readers for the correct first-choice CT diagnosis of UIP (κ = 0.79). The sensitivity, specificity, and positive predictive value of the CT diagnosis of UIP were 63%, 96%, and 96%, respectively. The sensitivity, specificity, and positive predictive value of the histological diagnosis of UIP were 73%, 74%, and 83%, respectively. The CT feature that best differentiated UIP from IIPs other than UIP was the extent of reticular pattern (odds ratio, 5.1). CONCLUSION: Surgical lung biopsy may not be warranted in patients with thin-section CT diagnosis of UIP.

Pulmonary Manifestations and Progression of Lung Disease in Juvenile-onset Mixed Connective Tissue Disease.

OBJECTIVE: To assess the occurrence and extent of interstitial lung disease (ILD) in patients with juvenile mixed connective tissue disease (JMCTD), compare pulmonary function in patients and matched controls, study associations between ILD and disease-related variables, and examine progression of pulmonary manifestations over time. METHODS: A cohort of 52 patients with JMCTD were examined in a cross-sectional study after a mean 16.2 (SD 10.3) years of disease duration with high-resolution computed tomography (HRCT) and pulmonary function tests (PFT) comprising spirometry, DLCO, and total lung capacity (TLC). Matched controls were examined with PFT. Previous HRCT and PFT were available in 37 and 38 patients (mean 8.8 and 10.3 yrs before study inclusion), respectively. RESULTS: Compared to controls, patients with JMCTD had lower forced vital capacity (FVC), DLCO, and TLC (p < 0.01). The most frequent abnormal PFT was DLCO in 67% of patients versus 17% of controls (p < 0.001). Fourteen patients (27%) had ILD on HRCT. Most had ILD in < 10% of their lungs. ILD was associated with low values for FVC and TLC, but not with DLCO. HRCT findings did not progress significantly over time, but FVC declined (p < 0.01). CONCLUSION: Compared to controls, patients with JMCTD had impaired pulmonary function. ILD was present in 27% of patients after a mean 16 years of disease duration, mostly as mild disease, and did not progress. ILD seems to be less common in juvenile-onset than in adult-onset MCTD, and ILD in JMCTD seems mostly mild and stable over time.

Donor-Site Morbidity After DIEAP Flap Breast Reconstruction-A 2-Year Postoperative Computed Tomography Comparison.

The study was undertaken to provide a more complete picture of donor-site morbidity following the deep inferior epigastric artery perforator (DIEAP) flap harvest in breast reconstruction. Most studies evaluating this subject have been performed using ultrasonography. Computed tomography (CT) might provide valuable information. METHODS: In 14 patients who were reconstructed with a DIEAP flap, donor-site morbidity was assessed by comparing routine preoperative CT abdomen with CT abdomen performed 2 years postoperatively. The anteroposterior diameter and transverse diameter (TD) of the rectus muscle were measured bilaterally within 4 standardized zones. Diastasis recti abdominis (DRA) was measured in the same zones. The abdominal wall was assessed for hernias, bulging, and seromas. RESULTS: The operated rectus muscle had a significantly increased anteroposterior diameter in 2 zones and decreased TD in 1 zone compared with preoperative measurements. Comparing the operated and nonoperated rectus muscles, the former had a significantly decreased TD in 1 zone. Supraumbilical DRA was significantly decreased with surgery, whereas infraumbilical DRA was significantly increased. No new hernias or bulging were found. Two patients had seroma formation in the abdominal wall. CONCLUSIONS: Symmetry of the 2 hemiabdomens is well preserved after DIEAP flap harvest; however, significant changes to the rectus muscles and DRA were observed. Hernia formation does not seem to be a postoperative complication of importance. The study indicates that DIEAP flaps result in limited donor-site morbidity, which for most patients does not outweigh the benefits of free perforator flap breast reconstruction.

Pulmonary Involvement in the Antisynthetase Syndrome: A Comparative Cross-sectional Study.

OBJECTIVE: Interstitial lung disease (ILD) is a major component of the antisynthetase syndrome, but quantitative data on longterm pulmonary outcome in antisynthetase syndrome are limited. In this study, the main aims were to compare pulmonary function tests (PFT) and the 6-min walking distance (6MWD) between patients with antisynthetase syndrome and healthy sex- and age-matched controls, to evaluate the extent of ILD by lung high-resolution computed tomography (HRCT), and to assess correlations between PFT measures and ILD extent. METHODS: Concurrent PFT and 6MWD were performed in 68 patients with antisynthetase syndrome and their individually matched controls. Additionally, in the patients, the extent of ILD was determined in 10 HRCT sections, expressed as percentage of total lung volumes. RESULTS: Median disease duration in the antisynthetase syndrome cohort was 71 months. Compared with the matched controls, the patients with antisynthetase syndrome had mean 28%, 27%, and 53% lower absolute values of forced vital capacity (FVC), forced expiratory volume in 1 s, and DLCO (p < 0.001). Mean difference in 6MWD between patients and controls was 116 m (p < 0.001). Median extent of ILD by HRCT was 20% (range 0-73) and correlated with FVC and DLCO. Pulmonary outcome did not differ between Jo1 and non-Jo1 subsets. CONCLUSION: To our knowledge, this study is the first to demonstrate a highly significant difference in PFT between patients with antisynthetase syndrome with 6 years of followup and healthy controls. DLCO displayed the highest difference with mean 53% lower value in the patients. FVC and DLCO correlated significantly with ILD extent, indicating these variables as appropriate outcome measures in antisynthetase syndrome-associated ILD.

Diagnosis of biopsy verified usual interstitial pneumonia by computed tomography.

OBJECTIVE: To identify the combination of clinical data and high resolution computed tomography (HRCT) features that best identified biopsy verified usual interstitial pneumonia (UIP). METHODS: The study included 91 patients with a tentative diagnosis of interstitial lung disease. All underwent clinical investigation, surgical lung biopsy and HRCT. Two independent readers assessed the HRCT images for the extent and pattern of abnormality. On the basis of the biopsy result the patients were categorized in three groups: 1) Usual interstitial pneumonia, 2) Other idiopathic interstitial pneumonias (IIPs) and hypersensitivity pneumonitis and 3) Other interstitial lung diseases. The diagnostic value of HRCT was investigated using likelihood ratio to estimate the post-test probability of UIP. RESULTS: We found that UIP was associated with significantly higher scores for reticular pattern and for bronchiectasis than the remaining patients (p < 0.001). Moreover, these scores showed a steeper cranial-caudal increase in patients with histologically verified UIP than in the remaining patients (p < 0.001). UIP was associated with lower scores for ground glass opacities (p < 0.001). Using Bayes theorem and likelihood ratio estimation we found that UIP could be diagnosed with 90% certainty in patients 60 years or older and restrictive pattern in spirometry provided that HRCT demonstrated at least 15% reticular pattern and no ground glass opacities. CONCLUSION: In older patients with a restrictive spirometry in whom HRCT demonstrates a reticular pattern without ground glass opacities surgical lung biopsy is not warranted for the diagnosis of UIP.

Development of pulmonary abnormalities in patients with common variable immunodeficiency: associations with clinical and immunologic factors.

BACKGROUND: Patients with common variable immunodeficiency (CVID) have low serum IgG, IgA, and/or IgM levels and recurrent airway infections. Radiologic pulmonary abnormalities and impaired function are common complications. It is unclear to what extent IgG replacement treatment prevents further pulmonary damage and how factors beside infections may contribute to progression of disease. OBJECTIVES: To study the development of pulmonary damage and determine how clinical and immunologic factors, such as serum IgG, may contribute to possible changes. METHODS: In a retrospective, longitudinal study of 54 patients with CVID already treated with immunoglobulins, we examined changes of lung function and findings on high-resolution computed tomography (HRCT), obtained at 2 time points (the date of the last pulmonary function measurement before April 2005 [T1] and the date of the measurement performed closest to 5 years earlier [T0]) 2 to 7 years apart and explored possible relations to clinical and immunologic factors such as levels of IgG, tumor necrosis alpha (TNF-alpha), and mannose-binding lectin (MBL) in serum. RESULTS: Despite a mean (SD) serum IgG level of 7.6 (2.3) g/L for all the patients during the entire study period, lung function decreased from T0 to T1. The combination of a low serum IgA level and serum MBL was associated with the presence of bronchiectasis and lower lung function and with worsening of several HRCT abnormalities from T0 to T1. Increased serum levels of TNF-alpha were related to deterioration of gas diffusion. A mean serum IgG level less than 5 g/L between T0 and T1 was associated with worsening of linear and/or irregular opacities seen on HRCT. CONCLUSION: For a period of 4 years, lung function and HRCT deteriorated in CVID patients treated with immunoglobulins.

High resolution computed tomography and pulmonary function in common variable immunodeficiency.

Patients with common variable immunodeficiency (CVID) have impaired production of immunoglobulins and hence recurrent airway infections, which in turn may lead to radiological changes and impaired lung function. Uncertainty exists about the nature and frequency of the radiological and the physiological abnormalities, and how they relate to each other. We reassessed high resolution computed tomography (HRCT) images in 65 patients, reported results from previously measured lung function tests, and studied relations between radiology, function and clinical variables. Airway obstruction, ventilatory restriction and impaired gas diffusion was found in 40, 34 and 21% of the patients, respectively. HRCT abnormalities were present in 94% of the subjects, mild changes being the most common. Bronchial wall thickening, found in two thirds of the patients, was related to airway obstruction and impaired gas diffusion. Linear and/or irregular opacities, the most frequent interstitial abnormality, was related to impaired gas diffusion. Bronchiectasis was found in more than half, but only severe bronchiectasis was related to airway obstruction. Since bronchial wall thickening and linear and/or irregular opacities are both frequent and important determinants of impaired pulmonary function, more attention should be given to these features in the follow up of CVID patients.