High-resolution computed tomography in the evaluation of fibrosing alveolitis

The Differences and Changes of Semi-Quantitative and Quantitative CT Features of Coronavirus Disease 2019 Pneumonia in Patients With or Without Smoking History

Objective: To assess CT features of COVID-19 patients with different smoking status using quantitative and semi-quantitative technologies and to investigate changes of CT features in different disease states between the two groups.

Methods: 30 COVID-19 patients with current smoking status (29 men, 1 woman) admitted in our database were enrolled as smoking group and 56 COVID-19 patients without smoking history (24 men, 32 women) admitted during the same period were enrolled as a control group. Twenty-seven smoking cases and 55 control cases reached recovery standard and were discharged. Initial and follow-up CT during hospitalization and follow-up CT after discharge were acquired. Thirty quantitative features, including the ratio of infection volume and visual-assessed interstitial changes score including total score, score of ground glass opacity, consolidation, septal thickening, reticulation and honeycombing sign, were analyzed.

Results: Initial CT images of the smoking group showed higher scores of septal thickening [4.5 (0–5) vs. 0 (0–4), p = 0.001] and reticulation [0 (0–5.25) vs 0 (0–0), p = 0.001] as well as higher total score [7 (5–12.25) vs. 6 (5–7), p = 0.008] with statistical significance than in the control group. The score of reticulation was higher in the smoking group than in the control group when discharged [0.89 (0–0) vs. 0.09 (0–0), p = 0.02]. The score of septal thickening tended to be higher in the smoking group than the control group [4 (0–4) vs. 0 (0–4), p = 0.007] after being discharged. Quantitative CT features including infection ratio of whole lung and left lung as well as infection ratio within HU (−750, −300) and within HU (−300, 49) were higher in the control group of initial CT with statistical differences. The infection ratio of whole lung and left lung, infection ratio within HU (−750), and within HU (−750, −300) were higher in the control group with statistical differences when discharged. This trend turned adverse after discharge and the values of quantitative features were generally higher in the smoking group than in the control group without statistical differences.

Conclusions: Patients with a history of smoking presented more severe interstitial manifestations and more residual lesion after being discharged. More support should be given for COVID-19 patients with a smoking history during hospitalization and after discharge.

pDCs in lung and skin fibrosis in a bleomycin-induced model and patients with systemic sclerosis

Fibrosis is the end result of most inflammatory conditions, but its pathogenesis remains unclear. We demonstrate that, in animals and humans with systemic fibrosis, plasmacytoid DCs (pDCs) are unaffected or are reduced systemically (spleen/peripheral blood), but they increase in the affected organs (lungs/skin/bronchoalveolar lavage). A pivotal role of pDCs was shown by depleting them in vivo, which ameliorated skin and/or lung fibrosis, reduced immune cell infiltration in the affected organs but not in spleen, and reduced the expression of genes and proteins implicated in chemotaxis, inflammation, and fibrosis in the affected organs of animals with bleomycin-induced fibrosis. As with animal findings, the frequency of pDCs in the lungs of patients with systemic sclerosis correlated with the severity of lung disease and with the frequency of CD4+ and IL-4+ T cells in the lung. Finally, treatment with imatinib that has been reported to reduce and/or prevent deterioration of skin and lung fibrosis profoundly reduced pDCs in lungs but not in peripheral blood of patients with systemic sclerosis. These observations suggest a role for pDCs in the pathogenesis of systemic fibrosis and identify the increased trafficking of pDCs to the affected organs as a potential therapeutic target in fibrotic diseases.

Characterization of lung cancer by amide proton transfer (APT) imaging: an in-vivo study in an orthotopic mouse model

Amide proton transfer (APT) imaging is one of the chemical exchange saturation transfer (CEST) imaging methods which images the exchange between protons of free tissue water and the amide groups (−NH) of endogenous mobile proteins and peptides. Previous work suggested the ability of APT imaging for characterization of the tumoral grade in the brain tumor. In this study, we tested the feasibility of in-vivo APT imaging of lung tumor and investigated whether the method could differentiate the tumoral types on orthotopic tumor xenografts from two malignant lung cancer cell lines. The results revealed that APT imaging is feasible to quantify lung tumors in the moving lung. The measured APT effect was higher in the tumor which exhibited more active proliferation than the other. The present study demonstrates that APT imaging has the potential to provide a characterization test to differentiate types or grade of lung cancer noninvasively, which may eventually reduce the need invasive needle biopsy or resection for lung cancer.

IL-4 polymorphisms, HRCT score and lung tissue markers in idiopathic pulmonary fibrosis

AIMS

We studied the influence of IL-4 gene polymorphisms on the IPF phenotype, i.e., extent of radiological changes (HRCT interstitial (IS) and alveolar (AS) score) and histopathological markers from lung biopsies.

PATIENTS AND METHODS

46 IPF patients underwent genotyping, 43 of them had HRCT and 14 patients had a surgical lung biopsy. The HRCT scans were evaluated for AS and IS. The histopathological evaluation comprised myofibroblast foci (MF), intensity of inflammation and fibrosis (Ashcroft score) and numbers of eosinophils and granulomas. For immunohistochemical evaluation primary antibodies against PAR-2, CD124, TGF beta, YY-1 and TSLP were used. The IL-4 and IL-4 R alpha gene polymorphisms were characterized.

RESULTS

We found a correlation between eosinophils in lung biopsies and AS. The Ashcroft score was higher in IL-4 HA 2 GCC and MF were more frequent in IL-4 HA 2 TCC carriers. A relationship was found between IL-4 (-1098) A2 T and PAR-2 expression and IL-4 (-590) A1 T, IL-4 HA1TTT and CD124 expression. AS was lower in IL-4 (-590) A1 C, in IL-4 HA1 TCC and in IL-4RA (+1902) A1 A carriers.

CONCLUSIONS

We suggest that the polymorphisms of IL-4 genes might influence the phenotype of IPF reflected by histopathological changes in lung biopsies and HRCT score.

Ultra-short echo time (UTE) MR imaging of the lung: comparison between normal and emphysematous lungs in mutant mice

PURPOSE

To investigate the utility of ultra-short echo time (UTE) sequence as pulmonary MRI to detect non-uniform disruption of lung architecture that is typical of emphysema.

MATERIALS AND METHODS

MRI of the lungs was conducted with a three-dimensional UTE sequence in transgenic mice with severe emphysema and their wild-type littermates in a 3 Tesla clinical MR system. Measurements of the signal intensity (SI) and transverse relaxation time (T2*) of the lung parenchyma were performed with various echo times (TEs) ranging from 100 micros to 2 ms.

RESULTS

Much higher SI of the lung parenchyma was observed at an UTE of 100 micros compared with longer TEs. The emphysematous lungs had reduced SIs and T2* than the controls, in particular at end-expiratory phase. The results suggested that both SI and T2* in lung parenchyma measured with the method represent fractional volume of lung tissue.

CONCLUSION

The UTE imaging provided MR signal from the lung parenchyma. Moreover, the UTE sequence was sensitive to emphysematous changes and may provide a direct assessment of lung parenchyma. UTE imaging has the potential to assist detection of localized pathological destruction of lung tissue architecture in emphysema.

MR microscopy of the lung in small rodents

Understanding how the mammalian respiratory system works and how it changes in disease states and under the influence of drugs is frequently pursued in model systems such as small rodents. These have many advantages, including being easily obtained in large numbers as purebred strains. Studies in small rodents are valuable for proof of concept studies and for increasing our knowledge about disease mechanisms. Since the recent developments in the generation of genetically designed animal models of disease, one needs the ability to assess morphology and function in in vivo systems. In this article, we first review previous reports regarding thoracic imaging. We then discuss approaches to take in making use of small rodents to increase MR microscopic sensitivity for these studies and to establish MR methods for clinically relevant lung imaging.

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.

Cytokine gene polymorphisms and high-resolution-computed tomography score in idiopathic pulmonary fibrosis

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a serious disease with unknown cause and the influence of cytokine gene polymorphisms is presumed in the etiology and pathogenesis of the disease. We used high-resolution computed tomography (HRCT) as a marker of disease stage and progression and compared the alveolar and interstitial score with IL-1, IL-4, IL-12, IL-1RA and IL-4RA cytokine gene polymorphisms.

SUBJECTS AND METHODS

The IPF patients were all Caucasians from the Czech Republic and consisted of 20 females and 10 males, with a mean age of 65 years, range 36-85. The HRCT results were evaluated by an experienced viewer using the interstitial and alveolar score scales, which were based on the IPF HRCT description system from Gay SE, Kazerooni EA, Tows GB, Lynch JP, Gross BH, Cascade PN, et al. [Idiopathic pulmonary fibrosis. Predicting response to therapy and survival. Am J Respir Crit Care Med 1998;157:1063-72]. We evaluated the polymorphisms of cytokine genes utilizing a PCR with sequence-specific primers method.

RESULTS

The HRCT alveolar score was more pronounced in IL-4 RA (+1902) AG heterozygotes. The HRCT interstitial score was less severe in the IL-12 (-1188) AA homozygotes. According to progression of the HRCT interstitial score, the CC homozygosity at IL-1 RA (mspa 111100), the AA homozygosity at IL-4 RA (+1902) and CC homozygosity at IL-4(+33) positions were more frequent in patients with stable disease compared to those with progressive disease.

CONCLUSIONS

We assume from our data that the polymorphisms of IL-4, IL-4RA, IL-1RA and IL-12 genes (genes of cytokines with regulatory activity) might influence the phenotype of IPF as shown by measurable changes in HRCT investigations.

The role of bronchoalveolar lavage in diffuse parenchymal lung diseases

PURPOSE OF REVIEW

To evaluate the role of bronchoalveolar lavage in the diagnosis of diffuse parenchymal lung diseases and review the recent literature published within the past 12 months.

RECENT FINDINGS

Diffuse parenchymal lung diseases are a heterogeneous group of disorders originating from the distal lung parenchyma. Despite different etiologies, the clinico-radiologic findings are usually alike and diagnosis can be challenging. Bronchoalveolar lavage and the analysis of cell counts are routine investigations for this group of disorders. Not only it can be used to see serial changes, it also important for providing information from a broader lung area. Although rarely diagnostic for a particular etiology, the predictive value of bronchoalveolar lavage differentials are reported to make some diagnoses more likely and exclude others like infections and tumors. This result is especially significant for the frequently encountered diffuse parenchymal diseases like sarcoidosis, usual interstitial pneumonia or extrinsic allergic alveolitis.

SUMMARY

Bronchoalveolar lavage is a convenient and safe procedure to apply for the diagnosis of diffuse parenchymal lung diseases especially to provide more information of the likelihood of the more common forms like sarcoidosis, extrinsic allergic alveolitis and usual interstitial pneumonia.

Histopathologic variability in usual and nonspecific interstitial pneumonias

Findings of surgical lung biopsy (SLB) are important in categorizing patients with idiopathic interstitial pneumonia (IIP). We investigated whether histologic variability would be evident in SLB specimens from multiple lobes in patients with IIP. SLBs from 168 patients, 109 of whom had multiple lobes biopsied, were reviewed by three pathologists. A diagnosis was assigned to each lobe. A different diagnosis was found between lobes in 26% of the patients. Patients with usual interstitial pneumonia (UIP) in all lobes were categorized as concordant for UIP (n = 51) and those with UIP in at least one lobe were categorized as discordant for UIP (n = 28). Patients with nonspecific interstitial pneumonia (NSIP) in all lobes were categorized as having fibrotic (n = 25) or cellular NSIP (n = 5). No consistent distribution of lobar histology was noted. Patients concordant for UIP were older (63 +/- 9 [mean +/- SD] yr; p < 0.05 as compared with all other groups) than those discordant for UIP (57 +/- 12 yr) or with fibrotic NSIP (56 +/- 11 yr) or cellular NSIP (50 +/- 9 yr). Semiquantitative high-resolution computed tomography demonstrated a varied profusion of fibrosis (p < 0.05 for all group comparisons), with more fibrosis in concordant UIP (2.13 +/- 0.62) than in discordant UIP (1.42 +/- 0.73), fibrotic NSIP (0.83 +/- 0.58), or cellular NSIP (0.44 +/- 0.42). Survival was better for patients with NSIP than for those in both UIP groups (p < 0.001), although survival in the two UIP groups was comparable (p = 0.16). Lobar histologic variability is frequent in patients with IIP, patients with a histologic pattern of UIP in any lobe should be classified as having UIP.