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.

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.

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.