Vibration Response Imaging in the Detection of Pleural Effusions: A Feasibility Study

Abstract

Background: Computerized analysis of the regional distribution of breath sound intensity during respiration has generated interest as a possible diagnostic modality. Objectives: We hypothesized that pleural effusions would create a dependent region of absent breath sounds and thus vibration response imaging (VRI) could be used in the detection of such pleural effusions. Methods: A prospective, single-blinded and open-labeled trial was carried out, and VRI recordings were compared to upright chest X-rays, bedside ultrasound examinations and volume of fluid drained via thoracentesis. VRI images were interpreted by a physician who was blinded to the patients’ clinical history, physical examination and diagnostic tests. Quantitative assessment of pleural effusion size in the VRI images was performed by ImageJ software and an automatic pixel count analysis. Results: VRI recordings were performed on 57 consecutive patients and correctly predicted the diagnosis in 45 cases (45/56, 80%) as compared to chest X-rays. The calculated sensitivity, specificity, positive predictive value and negative predictive value for diagnosis of pleural effusion were 86% (62/72), 93% (37/40), 95% (62/65) and 79% (37/47), respectively, in a per-hemithorax analysis. In the quantification of effusion size, there were high correlations between VRI images and chest X-ray area as assessed by ImageJ (r = 0.67) and pixel count (r = –0.77). The level of agreement between VRI readings and ultrasonography was 75% (41/55), and correlation with the volume of fluid drained in therapeutic thoracentesis was moderate (r = –0.49). No side effects from the VRI recordings were documented. Conclusions: VRI can be used to detect and quantify pleural effusions.

Effects of Bronchodilators on Regional Lung Sound Distribution in Patients with Chronic Obstructive Pulmonary Disease

“…Regional lung sounds may be influenced by improvements in regional lung ventilation induced by bronchodilator administration. Vibration response imaging (VRI) is a commercially available acoustic lung imaging system that displays breath sound energy distribution as a dynamic grey-scale image [12,13,14,15]. VRI is a noninvasive, radiation-free technique that requires minimal patient effort and can be transported to the bedside [16,17].…”

Computerized Lung Acoustic Monitoring Can Help to Differentiate between Various Chest Radiographic Densities in Critically Ill Patients

“…Its diagnostic capability has been described in non-critically ill patients, particularly in pneumonia [34], pleural effusion [35] and pneumothorax [36]. Experience in critical care includes assessment of asymmetric lung diseases [37] as well as the setting of mechanical ventilator parameters such as mode of ventilation [38] or positive end-expiratory pressure [39].…”

A Left Hemithorax Mystery

“…Oral contrast studies, CT, laparoscopy, thoracoscopy and ultrasonography can be of aid in detecting a diaphragmatic injury. The extent of herniation and related complications are best shown by CT. A quick, mobile ultrasound examination at the bedside would probably also have been diagnostic in this particular case [5,6] . Ultrasound confirms the indication for pleurocentesis, increases the accuracy of pleural puncture site selection and should be routinely employed before a pleural tap is attempted [7] .…”