Quantitative assessment of pneumothorax by using Shannon entropy of lung ultrasound M-mode image and diaphragmatic excursion based on automated measurement

Jui Fang; Yu-Cheng Shen; Yen-Nien Ting; Hsin-Yuan Fang; Yi-Wen Chen

doi:10.21037/qims-23-636

Quantitative assessment of pneumothorax by using Shannon entropy of lung ultrasound M-mode image and diaphragmatic excursion based on automated measurement

Quant Imaging Med Surg. 2024 Jan 3;14(1):123-135. doi: 10.21037/qims-23-636. Epub 2023 Nov 29.

Authors

Jui Fang^#¹, Yu-Cheng Shen^#², Yen-Nien Ting¹, Hsin-Yuan Fang^{2

3}, Yi-Wen Chen^{1

4

5}

Affiliations

¹ Research & Development Center for x-Dimensional Extracellular Vesicles, China Medical University Hospital, Taichung City.
² Division of Thoracic Surgery, Department of Surgery, China Medical University Hospital, Taichung City.
³ School of Medicine, College of Medicine, China Medical University, Taichung City.
⁴ Graduate Institute of Biomedical Sciences, China Medical University, Taichung City.
⁵ High Performance Materials Institute for xD Printing, Asia University, Taichung City.

^# Contributed equally.

Abstract

Background: Lung ultrasound (LUS) and diaphragm ultrasound (DUS) are the appropriate modalities for conservative observation to those patients who are with stable pneumothorax, as well as for the timely detection of life-threatening pneumothorax at any location, due to they are portable, real-time, relatively cost effective, and most important, without radiation exposure. The absence of lung sliding on LUS M-mode images and the abnormality of diaphragmatic excursion (DE) on DUS M-mode images are the most common and novel diagnostic criteria for pneumothorax, respectively. However, visual inspection of M-mode images remains subjective and quantitative analysis of LUS and DUS M-mode images are required.

Methods: Shannon entropy of LUS M-mode image (ShanEn_LM) and DE based on the automated measurement (DE_AM) are adapted to the objective pneumothorax diagnoses and the severity quantifications in this study. Mild, moderate, and severe pneumothoraces were induced in 24 male New Zealand rabbits through insufflation of room air (5, 10 and 15, and 25 and 40 mL/kg, respectively) into their pleural cavities. In vivo intercostal LUS and subcostal DUS M-mode images were acquired using a point-of-care system for estimating ShanEn_LM and DE_AM.

Results: ShanEn_LM and DE_AM as functions of air insufflation volumes exhibited U-shaped curves and were exponentially decreasing, respectively. Either ShanEn_LM or DE_AM had areas under the receiver operating characteristic curves [95% confidence interval (CI)] of 1.0000 (95% CI: 1.0000-1.0000), 0.9833 (95% CI: 0.9214-1.0000), and 0.9407 (95% CI: 0.8511-1.0000) for differentiating between normal and mild pneumothorax, mild and moderate pneumothoraces, and moderate and severe pneumothoraces, respectively.

Conclusions: Our findings imply that the combination of ShanEn_LM and DE_AM give the promising potential for pneumothorax quantitative diagnosis.

Keywords: Pneumothorax; Shannon entropy (ShanEn); diaphragm ultrasound (DUS); diaphragmatic excursion (DE); lung ultrasound M-mode image (LUS M-mode image).