Comparative analysis of density histograms and visual scores in incremental and volumetric high-resolution computed tomography of the chest in idiopathic pulmonary fibrosis patients.

BACKGROUND: Volumetric high-resolution computed tomography (HRCT) of the chest has recently replaced incremental CT in the diagnostic workup of idiopathic pulmonary fibrosis (IPF). Concomitantly, visual and quantitative scores have been proposed for disease extent assessment to ameliorate disease management. PURPOSE: To compare the performance of density histograms (mean lung attenuation, skewness, and kurtosis) and visual scores, along with lung function correlations, in IPF patients submitted to incremental or volumetric thorax HRCT. MATERIAL AND METHODS: Clinical data and CT scans of 89 newly diagnosed and therapy-naive IPF patients were retrospectively evaluated. RESULTS: Forty-six incremental and 43 volumetric CT scans were reviewed. No differences of density histograms and visual scores estimates were found by comparing two HRCT techniques, with an optimal inter-operator agreement (concordance correlation coefficient >0.90 in all instances). Single-breath diffusing lung capacity for carbon monoxide (DLCOsb) was inversely related with the Best score (r = -00.416; p = 0.014), the Kazerooni fibrosis extent (r = -0.481; p = 0.004) and the mean lung attenuation (r = -0.382; p = 0.026), while a positive correlation was observed with skewness (r = 0.583; p = 0.001) and kurtosis (r = 0.543; p = 0.001) in the incremental HRCT sub-group. Similarly, in the volumetric CT sub-cohort, DLCOsb was significantly associated with skewness (r = 0.581; p = 0.007) and kurtosis (r = 0.549; p = 0.018). Correlations with visual scores were not confirmed. Forced vital capacity significantly related to all density indices independently on HRCT technique. CONCLUSIONS: Density histograms and visual scores similarly perform in incremental and volumetric HRCT. Density quantification displays an optimal reproducibility and proves to be superior to visual scoring as more strongly correlated with lung function.

First Description of the Hyperpnea-Hypopnea Periodic Breathing in Patients with Interstitial Lung Disease-Obstructive Sleep Apnea: Treatment Implications in a Real-Life Setting.

There is evidence that hypopneas are more common than apneas in obstructive sleep apnea (OSA) related to idiopathic pulmonary fibrosis (IPF). We investigated the frequency distribution of hypopneas in 100 patients with interstitial lung diseases (ILDs) (mean age 69 yrs ± 7.8; 70% males), including 54 IPF cases, screened for OSA by home sleep testing. Fifty age- and sex-matched pure OSA patients were included as controls. In ILD-OSA patients the sleep breathing pattern was characterized by a high prevalence of hypopneas that were preceded by hyperpnea events configuring a sort of periodic pattern. This finding, we arbitrarily defined hyperpnea-hypopnea periodic breathing (HHPB), was likely reflecting a central event and was completely absent in control OSA. Also, the HHPB was highly responsive to oxygen but not to the continuous positive pressure support. Thirty-three ILD-OSA patients (42%) with a HHPB associated with a hypopnea/apnea ratio ≥3 had the best response to oxygen with a median residual AHI of 2.6 (1.8-5.6) vs. 28.3 (20.7-37.8) at baseline (p < 0.0001). ILD-OSA patients with these characteristics were similarly distributed in IPF (54.5%) and no-IPF cases (45.5%), the most of them being affected by moderate-severe OSA (p = 0.027). Future studies addressing the pathogenesis and therapy management of the HHPB should be encouraged in ILD-OSA patients.

Performance of a new quantitative computed tomography index for interstitial lung disease assessment in systemic sclerosis.

Quantitative high resolution computed tomography (HRCT) may objectively assess systemic sclerosis (SSc)-interstitial lung disease (ILD) extent, using three basic densitometric measures: mean lung attenuation (MLA), skewness, and kurtosis. This prospective study aimed to develop a composite index - computerized integrated index (CII) - that accounted for MLA, skewness, and kurtosis by means of Principal Component Analysis over HRCTs of 83 consecutive SSc subjects, thus eliminating redundancies. Correlations among CII, cardiopulmonary function and immune-inflammatory biomarkers (e.g. sIL-2Rα and CCL18 serum levels) were explored. ILD was detected in 47% of patients at visual HRCT assessment. These patients had worse CII values than patients without ILD. The CII correlated with lung function at both baseline and follow-up, and with sIL-2Rα and CCL18 serum levels. The best discriminating CII value for ILD was 0.1966 (AUC = 0.77; sensitivity = 0.81 [95%CI:0.68-0.92]; specificity = 0.66 [95%CI:0.52-0.80]). Thirty-four percent of patients without visual trace of ILD had a CII lower than 0.1966, and 67% of them had a diffusing lung capacity for CO <80% of predicted. We showed that this new composite CT index for SSc-ILD assessment correlates with both lung function and immune-inflammatory parameters and could be sufficiently sensitive for capturing early lung density changes in visually ILD-free patients.

Lung involvement in "stable" undifferentiated connective tissue diseases: a rheumatology perspective.

Previous studies of the occurrence of interstitial lung disease (ILD) in undifferentiated connective tissue diseases (UCTD) were conducted in patients admitted to Respiratory Medicine Units. The aim of the present prospective study was to investigate lung involvement in UCTD patients admitted to a Rheumatology Unit. Eighty-one consecutive UCTD patients were enrolled in the study. Each patient underwent history and physical examination, routine laboratory investigations, antinuclear antibody (ANA) profiling, B-mode echocardiography, and lung function study according to previously reported methods. Lung high resolution computed tomography (HRCT) was performed in patients who provided informed consent. Six patients (7.4%) had a history of grade II dyspnea. Three of them had a DLCO ranging from 42 to 55% of the predicted value; and a HRCT-documented ILD with a non-specific interstitial pneumonia (NSIP) pattern. Symptoms in the other three patients were due to cardiac disease. None of the 75 asymptomatic patients, had relevant findings at physical examination, 26/75 had a DLCO <80% (<70% in 10 cases). Of these, 3 of the 30 patients who underwent lung HRCT were affected by NSIP-ILD. Six of the 81 enrolled were affected by ILD, which was symptomatic in three patients. A higher percentage of patients had a reduced DLCO. The latter finding may reflect a preradiographic ILD or a preechocardiographic pulmonary vascular disease.

Exercise related ventilation dynamics and clinical correlates in patients with fibrotic idiopathic interstitial pneumonias.

Assessment of exercise performance is a key component in the management of interstitial lung diseases, as its limitation may occur very early. Aim of the present study was to assess ventilation dynamics in combination with pulse-oximetry changes in 54 clinically stable patients affected by idiopathic pulmonary fibrosis or idiopathic fibrotic nonspecific interstitial pneumonia. Testing was successfully performed with the Spiropalm 6-MWT Hand-held spirometer by the majority of cases (94%). End test oxygen saturation (SpO2) values <88% were common in most of patients (76%), with a mean distance walked of 403 meters. Ventilation significantly increased due to the contribution of the tidal volume and the respiratory frequency (RF). This finding was associated with a decrease of the end of test respiratory reserve (RR), that was <20% in 9 cases (17.6%). Lung function was inversely related to the end of test RF, while a positive correlation occurred with the end of test RR and the estimated maximal voluntary ventilation (MVV). RR was also a predictive factor of declining forced vital capacity and lung diffusion capacity for carbon monoxide (DLCO) over a 6-month period. Further factors of DLCO impairment were low SpO2 and MVV. Comparison with the cardio-pulmonary exercise test (CPET) showed that the 6-MWT end of test RR was inversely related to the CPET-derived peak RF and VE/VCO2 suggesting RR as pivotal in exercise limitation assessment. Our results open challenging perspectives in an unexplored field. Future research will include management of latent respiratory failure and monitoring of disease progression and therapy response.