Transthoracic ultrasound shear wave elastography for the study of subpleural lung lesions.

PURPOSE: The aim of this study was to assess whether new-generation shear wave elastography (SWE) is suitable for the characterization of lung subpleural lesions. METHODS: In total, 190 consecutive patients with subpleural lung lesions received ultrasonography and SWE. Patients with suspected malignancy underwent ultrasound-guided transthoracic needle biopsy. Final diagnoses were made on the basis of patients' clinical course, microbiological studies, and histological results. SWE was also performed in 25 healthy volunteers. RESULTS: We found no statistically significant differences in stiffness between lung carcinomas, lung metastases, and pneumonia (P=0.296) or between different histological types of lung cancer (P=0.393). Necrosis was associated with reduced stiffness in pneumonia. Excluding necrotic lesions, pneumonia showed higher stiffness than lung carcinomas (2.95±0.68 m/s vs. 2.60±0.54 m/s, P=0.006). Chronic pneumonia showed increased stiffness (3.03±0.63 m/s), probably due to the presence of fibrotic tissue on histology. Pleural effusion was associated with a statistically significant reduction in stiffness, both in lung carcinomas (P=0.004) and lung metastases (P=0.002). The presence of air in healthy lung tissue may lead to incorrect speed estimates due to shear wave reflection (very high values, 14.64±2.19 m/s). CONCLUSION: Transthoracic SWE could not distinguish lung malignancy from pneumonia, or between different histological types of lung carcinomas. In particular, SWE seems unable to resolve the clinical dilemma of chronic subpleural consolidations.

Airway-centered Fibroelastosis Accompanied by Subpleural Lesions of Unknown Cause in a Young Man Who Later Developed Pulmonary Hypertension.

A 26-year-old man with a history of bronchial asthma was found to have high-density shadows along the bronchovascular bundle and in the subpleural area on computed tomography of the chest. Surgical lung biopsy specimens from the right S5 showed fibroelastosis in the subpleural and central airway area with alveolar destruction. He was diagnosed with airway-centered fibroelastosis of unknown cause after multidisciplinary discussions. The patient developed pulmonary hypertension and died 6 years later. The patient was younger in comparison to patients in earlier reports and had more obvious subpleural fibroelastic lesions in the upper lobes than in previously described cases.

Do respiratory comorbidities limit the diagnostic usefulness of ultrasound-guided needle aspiration for subpleural lesions?

BACKGROUND: The usefulness of ultrasound-guided needle aspiration for subpleural lesions has been reported. However, no reports have evaluated its usefulness and safety in patients with respiratory comorbidities such as chronic obstructive pulmonary disease (COPD) and interstitial pneumonia (IP), which can increase the risk of iatrogenic pneumothorax. In this study, we evaluated the influence of chronic respiratory diseases (CRDs) on the usefulness and safety of ultrasound-guided needle aspiration for subpleural lesions. METHODS: Between January 2000 and September 2011, we examined 144 patients with intrapulmonary subpleural lesions. We retrospectively reviewed clinical data, including lesion size on thoracic computed tomography (CT), ultrasound findings, pathological findings obtained by ultrasound-guided needle aspiration, final diagnosis, and complications. RESULTS: A positive definitive diagnosis was obtained in 74.3% of all 144 patients; 84.7% patients with malignant diseases, including lung cancer; and 26.9% patients with benign diseases. Of the 144 patients, 64 belonged to the CRD group and 80 to the non-CRD group. The former included 31 patients with COPD, six with emphysematous changes on thoracic CT, 17 with IP, and 10 with other diseases. The positive rate of diagnosis for malignant diseases was 84.7% in the CRD group, which was the same as that in the non-CRD group. With regard to complications related to ultrasound-guided aspiration, there were only two cases of pneumothorax in the CRD group and one in the non-CRD group. CONCLUSION: Ultrasound-guided aspiration is safe and useful for subpleural lesions, particularly malignant lesions, even in patients with respiratory comorbidities such as COPD and IP.