Deep-Inspiration Breath-Hold Strategy Improves Image Quality of Transthoracic Lateral Shoulder Radiography

Background/Objectives: Transthoracic lateral shoulder radiography serves as an important method for traumatic shoulder injuries and dislocations, but tissue overlap and breathing motion often compromise image quality and are particularly prominent in obese patients. This study aims to compare the image quality differences between the deep-inspiration breath-hold (DIBH) strategy and the routine free-breathing (FB) method in transthoracic lateral shoulder radiography for patients with different body mass indices (BMI), and to clarify the clinical application value of the breath-holding strategy. Methods: A total of 128 patients with traumatic shoulder injuries, glenohumeral dislocation, postoperative follow-up, and symptomatic degenerative shoulder osseous lesions were prospectively enrolled to undergo radiography. Anteroposterior (AP) projection and transthoracic lateral views applying both FB and DIBH methods were performed. They were stratified into three groups (BMI < 24 kg/m², 24-28 kg/m², and ≥28 kg/m²). Two experienced radiologists independently evaluated the subjective image quality regarding anatomical depiction and abnormality visualization between the two methods, which were compared using a four-point scale (1, poor; 4, excellent), with inter-observer consistency analyzed. The edge sharpness (ES) was also calculated and compared quantitatively. The interaction effect of BMI grouping and respiratory mode regarding ES measurement was evaluated; cumulative-link mixed-effects models with subject-level random intercepts were also fitted to test whether the benefit of DIBH varied with BMI grouping for the subjective scores. Results: The DIBH method presented superior anatomical depiction scores relative to the FB method (p < 0.001). For reader 1, median scores were 3.0 (interquartile range, IQR, 3.0-3.0) for FB radiographs and 3.5 (IQR, 3.0-4.0) for the DIBH method (z = -8.014, p < 0.001). Consistently higher median scores were also documented by reader 2 for the DIBH method: 3.0 (IQR, 3.0-3.0) for the FB method versus 3.0 (IQR, 3.0-4.0) for the DIBH method (z = -7.616, p < 0.001). For lesion depiction, the scores of the DIBH images were better than those of the FB images with p < 0.05 for reader 1 (p = 0.005) and reader 2 (p = 0.046). Moderate-to-excellent inter-reader consistency was observed. The mean ES of the DIBH method was significantly higher than that of the FB method (2.27 ± 0.73 vs. 2.02 ± 0.70; paired t = 4.80, df = 127, p < 0.001). No significant differences in ES values or subjective scores for DIBH images existed among three BMI subgroups (p > 0.05); FB anatomical scores differed significantly for both readers (reader 1: p = 0.041; reader 2: p = 0.026). There was no significant interaction between the BMI grouping and the respiratory mode regarding ES measurement (F = 0.061, df = 2, 125, p = 0.941). Conclusions: The deep-inspiration breath-hold strategy significantly improves image quality and lesion conspicuity for depicting shoulder abnormalities compared with the routine free-breathing method in transthoracic lateral shoulder radiography, without requiring additional equipment or changes to the radiographic system, when interpreted in conjunction with the corresponding AP radiograph in clinical practice for cooperative patients.