Chest anteroposterior diameter measurement: Comparison of ultrasonic and manual methods across different BMI categories

Chest anteroposterior diameter (APD) measurement is a critical metric in evaluating thoracic dimensions, particularly in assessing conditions like pectus excavatum and guiding interventions such as laryngoscopy and cardiopulmonary resuscitation. The lateral distance measurement of the thoracic cavity using the computed tomography image provides APD, but they expose the subject to radiation. Though the manual method of chest APD measurement using a wooden ruler is radiation-free, it is time-consuming and prone to human errors. This study proposes a novel and radiation-free method of measuring chest APD using an ultrasonic sensor. The accuracy and reliability of the measured chest APD using the ultrasonic method were compared with the manual method across three distinct BMI categories of 150 participants. The measured chest APD using ultrasonic and manual methods for underweight, normal, and obese participants ranges from 17-18 cm, 18.5-20.5 cm, and 23.75-25 cm, respectively. The statistical analyses, including paired t-tests and intra-class correlation coefficients (ICC), were performed to assess agreement between the two methods. The paired t-test manifests no significant difference between the mean APD measured using ultrasonic and manual methods with p-values of 0.8742 (underweight), 0.7390 (normal), and 0.7998 (obese). The ICC values obtained from the intra- and inter-observers for the ultrasonic and manual methods were ICC ≥ 0.93, 0.80 ≤ ICC ≤ 0.82 and 0.91, and 0.78. The ICC value obtained from the intra- and inter-observers for the ultrasonic method was high, so the ultrasonic method is better than the manual method. This study concludes that the ultrasonic method provides a radiation-free alternative to the manual method, making it suitable for routine clinical use globally.