Comparison of two methods for the in-vivo diagnosis of Helicobacter pylori infection using a tablet of 13C-urea.

BACKGROUND: The urea Breath-test is a widely-used method to detect the presence of Helicobacter pylori (HP) infection. Recently, new technologies were introduced, to obtain an immediate test result by continuous breath samples analysis after labeled urea intake. The total test duration is shorter than 20 minutes. METHODS: The study compared two diagnostic methods requiring the administration of EXPIROBACTER® (Sofar SpA, Trezzano Rosa, Milan, Italy) 100 mg as a source of labeled urea. Subjects with clinical indication to urea breath test for H. pylori were enrolled. This study was designed to directly compare the accuracy of urea breath test performed with both the classic method and BreathID® (Exalenz Bioscience, Inc., Manasquan, NJ, USA). Each patient simultaneously underwent to both tests, to measure the concordance between the results (positive or negative test), minimizing the risks of differences related to the intra- and inter-individual variability. RESULTS: Forty-six subjects were enrolled. Forty-one patients (91.1%) were found negative with both methods and 5 (10.1%) were positive for H. pylori infection in both tests. Correlation between the two methods was excellent (κ=1.00). BreathID® was significantly preferred by patients, with a 7.83 (95% CI: 3.35 to 12.30, P=0.001) difference in mean patient satisfaction, measured by a Visual Analogue Scale (VAS). No adverse event was observed. CONCLUSIONS: Correlation between the two methods was excellent. Moreover, the patient satisfaction, measured by VAS, showed a significantly greater acceptance of BreathID® method. This study support the use of a product containing 13C-urea 100 mg and citric acid for immediate determination of HP infection by urea breath test performed with BreathID®.

Whole-lung densitometry versus visual assessment of emphysema.

We compared whole-lung densitometry with visual evaluation of pulmonary emphysema. Thirty patients with chronic obstructive pulmonary disease underwent multi-detector CT (150 mAs and 0.75 collimation) with double reconstruction: thick (5-mm) slices with smooth filter for whole-lung densitometry and thin (1 mm) slices with sharp filter for visual assessment (one of every ten slices). Densitometry and visual assessment were performed by three operators each, and the time required for assessment, the inter-observer agreement and the correlation with the results of the diffusion capacity of carbon monoxide (DL(CO)) in the same patients were computed. The average time for densitometry (8.49 +/- 0.13 min) was significantly longer (p < 0.0001) than that for visual evaluation (5.14 +/- 0.11 min). However, the inter-operator agreement ranged between "moderate" to "almost perfect" for densitometry (kappa range 0.58-0.87) and "slight" for visual (kappa = 0.20) assessment. The correlation coefficients of DL(CO) with relative area at -960 and -970 Hounsfield units (HU) (both r = -0.66) and of the first percentile point of lung density (r = 0.66) were slightly stronger than that of the visual score (r = -0.62). Densitometry should be preferred to visual assessment because it enables a more reproducible evaluation of the extent of pulmonary emphysema, which can be carried out on the entire lung in a reasonable amount of time.

Prevalence and correlates of pulmonary emphysema in smokers and former smokers. A densitometric study of participants in the ITALUNG trial.

We assessed with computed tomography (CT) densitometry the prevalence of emphysema in 266 (175 men and 91 women; mean age 64 +/- 4 years) smokers and former smokers enrolled in the ITALUNG trial of lung cancer screening with low-dose thin-slice CT. Whole-lung volume and the relative area at -950 Hounsfield units (RA(950)) and mean lung attenuation (MLA) in 1 of every 10 slices (mean, 24 slices per subject) were measured. Lung volume, MLA and RA950 significantly correlated each other and with age. Average RA950 >6.8% qualifying for emphysema was present in 71 (26.6%) of 266 subjects, with a higher prevalence in men than in women (30.3% vs 19.8%; p = 0.003). Only in smokers was a weak (r = 0.18; p = 0.05) correlation between RA950 and packs/year observed. In multiple regression analysis, the variability of RA950 (R2 = 0.24) or MLA (R2 = 0.34) was significantly, but weakly explained by age, lung volume and packs/year. Other factors besides smoking may also have a significant role in the etiopathogenesis of pulmonary emphysema.

Lung CT densitometry in systemic sclerosis: correlation with lung function, exercise testing, and quality of life.

BACKGROUND: To ascertain if analysis of lung density histograms in thin-section CT was more reproducible than visual assessment of lung changes in systemic sclerosis (SSc), and if such density histogram parameters as mean lung attenuation (MLA), skewness, and kurtosis could more closely reflect pulmonary function as well as exercise and quality of life impairment. METHODS: The intraoperator and interoperator reproducibility of visual and densitometric lung CT analysis in 48 SSc patients examined with CT were evaluated by means of weighted kappa statistics. Univariate and multivariate regression analyses were applied to evaluate the relationship of visual and densitometric CT measurements with functional parameters including functional residual capacity (FRC), FVC, FEV(1), diffusion capacity of the lung for carbon monoxide (Dlco), 6-min walking testing (6MWT), and health-related quality of life questionnaire (QLQ) parameters. RESULTS: The intraoperator and interoperator reproducibility of MLA (intraobserver weighted kappa = 0.97; interobserver weighted kappa = 0.96), skewness (intraobserver weighted kappa = 0.89; interobserver weighted kappa = 0.88), and kurtosis (intraobserver weighted kappa = 0.89; interobserver weighted kappa = 0.88) were higher than those of visual assessment (intraobserver weighted kappa = 0.71; interobserver weighted kappa = 0.69). In univariate analysis, only densitometric measurements were correlated with some exercise and QLQ parameters. In multivariate analysis, MLA (square regression coefficient corrected [R(2)c] = 0.70), skewness (R(2)c = 0.78), and kurtosis (R(2)c = 0.77) were predicted by FRC, FVC, Dlco, 6MWT, and QLQ parameters, while visual assessment was associated only with FRC and FVC (R(2)c = 0.40). CONCLUSIONS: In SSc, densitometric analysis is more reproducible than visual assessment of lung changes in thin-section CT and more closely correlated to pulmonary function testing, 6MWT, and QLQ. Density histogram parameters may be useful for cross-sectional and longitudinal studies of lung involvement in SSc.

Thin-section and low-dose volumetric computed tomographic densitometry of the lung in systemic sclerosis.

OBJECTIVE: To correlate lung density measurements with the results of visual assessment of thin-section computed tomography (CT) and of pulmonary function tests (PFT) in Systemic Sclerosis (SSc). METHODS: Thirty-nine SSc patients underwent sequential thin-section CT and spiral low-dose whole-lung acquisitions. The thin-section CT scans were evaluated with a dedicated visual scale. Mean lung density, skewness, and kurtosis were calculated from the lung density histogram. In addition from the spiral low-dose acquisition, the lung volume was computed. The visual score, the densitometric parameters, and the lung volume were correlated with the PFT. RESULTS: Mean lung density, skewness, and kurtosis computed from thin-section (R = 0,66; R = -0,74; R = -0,75) and low-dose volumetric (R = 0,72; R = -0,71; R = -0,71) CT and the lung volume (R = -0.54) correlated with the visual score. Densitometric values and lung volume consistently better correlated with PFT than the visual score. CONCLUSIONS: In SSc the histogram results are more closely correlated to PFT than the visual score. The low-dose spiral CT seems ideal for longitudinal studies.

Chronic obstructive pulmonary disease: thin-section CT measurement of airway wall thickness and lung attenuation.

PURPOSE: To prospectively evaluate airway wall thickness and lung attenuation at spirometrically gated thin-section computed tomography (CT) in patients with chronic obstructive pulmonary disease (COPD) and to correlate gated CT findings with pulmonary function test (PFT) results. MATERIALS AND METHODS: The ethical committee approved the study, and all patients gave informed consent. Forty-two consecutive patients with COPD (20 with and 22 without chronic bronchitis [CB]) underwent gated thin-section CT and PFTs on the same day. The percentage wall area (PWA) and the thickness-to-diameter ratio (TDR) for all depicted bronchi that were round and larger than 2 mm in diameter, the mean lung attenuation (MLA), and the pixel index (PI) at -950 HU were determined. The reproducibility of the airway measurements was preliminarily tested by performing a five-trial examination in a patient with COPD and in a control patient. Differences in airway and lung attenuation measurements between the patients with and those without CB were evaluated at Mann-Whitney U testing. Simple and multiple regression analyses were used to assess the correlation between thin-section CT and PFT measurements. RESULTS: The mean intraoperator coefficient of variation for airway measurements was 7.8% (range, 3.8%-13.4%). An average of nine bronchi per patient were assessed. Patients with CB had significantly higher PWAs, TDRs, and MLAs and significantly lower PIs than patients without CB (P < .05 for all values). The combination of PWA, TDR, and PWA normalized to body weight correlated significantly (P < .05) with the forced expiratory volume in 1 second-to-slow vital capacity ratio and the diffusing capacity of the lung for carbon monoxide in patients with but not in patients without CB. PFT results correlated better with MLA and PI in patients without CB. CONCLUSION: Bronchial wall measurements differ between patients who have COPD with CB and those who have COPD without CB. The correlation between airway dimensions and indexes of airway obstruction in patients with COPD and CB indicates that the bronchial tree is the site of anatomic-functional alterations in this patient group.

Spirometric-gated computed tomography quantitative evaluation of lung emphysema in chronic obstructive pulmonary disease: a comparison of 3 techniques.

OBJECTIVE: To compare the quantitative assessment of pulmonary emphysema with spirometric-gated computed tomography (gated CT) using 3 different acquisition techniques and to determine if low-current spiral CT could be used effectively to quantitate emphysema. METHODS: Eleven patients with chronic obstructive pulmonary disease (COPD) underwent gated CT and pulmonary function tests (PFTs). Spiral whole-lung 10-mm collimation acquisitions at standard (146 mAs) and low (43 mAs) current and sequential 3-slice 1-mm collimation high-resolution computed tomography (HRCT) acquisitions at standard current were obtained at 90% of the patient's vital capacity. The mean lung density (MLD) and the pixel index (PI) derived from the 3 data sets were compared using one-way analysis of variance and correlated with PFTs using linear regression. Moreover, the radiation dose associated with each technique was measured. RESULTS: The MLDs were not significantly different. The PIs calculated from the standard- and low-current spiral acquisitions were similar, and both were significantly different from that of HRCT. The MLDs correlated with the PFTs in standard-current spiral and HRCT but not in low-current spiral acquisitions, whereas the PIs correlated with the PFTs in all 3 techniques. High-resolution computed tomography implied the lowest dose (0.08 mSv) compared with low-current (1.2 mSv) and standard-current (4 mSv) spiral techniques. CONCLUSIONS: Low- and standard-dose spiral CT provides similar lung density data in COPD. The combination of low-dose whole-lung spiral CT and 3-slice HRCT represents the best compromise between the amount of information provided and radiation exposure to the patient and could be substituted for standard-dose spiral CT for quantitative evaluation of COPD.

Comparison of spirometric-gated and -ungated HRCT in COPD.

PURPOSE: The purpose of this work was to evaluate feasibility of spirometric-gated high-resolution computed tomography (HRCT) in patients with chronic obstructive pulmonary disease (COPD) and to compare the lung density CT measurements obtained with and without spirometric control of lung volume. METHOD: Twenty-nine patients with COPD underwent pulmonary function tests and spirometric-gated (3 slices at 10% and 90% of vital capacity) and -ungated (12 slices at maximum expiration and inspiration) HRCT in the same day. Four lung density measurements (inspiratory pixel index, expiratory pixel index, inspiratory and expiratory mean lung density) derived from gated and ungated acquisitions were compared using the nonparametric Wilcoxon test, the line of equality, and the Bland and Altman test. RESULTS: The vital capacity measured at pulmonary function tests and on the CT table showed a substantial agreement. All but one patient completed the gated and ungated examination, but only 8 (28%) of 28 patients reached the expiratory and inspiratory gating level for CT acquisitions at the first attempt. Only the inspiratory mean lung density derived from the 3 gated and 12 ungated slices showed borderline agreement. Other CT measurements, and notably all those from the 3 gated and ungated scans, acquired at the same anatomic level, did not agree. CONCLUSIONS: Although the procedure can be difficult for individual patients, spirometric gating significantly influences the lung density CT measurements and might improve standardization of CT evaluation of COPD.