ABSTRACT
Background and/or Objectives: To determine the feasibility of utilizing M-Mode (motion-mode) for ultrasound imaging and data collection of the diaphragm. Design(s): A review of data collected during a prospective, randomized controlled trial. Setting(s): Research hospital Participants: 12 adults (mean age = 39 years) with lab-confirmed SARS-CoV2 infection and persistent exercise intolerance affecting function. Musculoskeletal M-Mode imaging of the left and right diaphragm were acquired using a Samsung RS85 Prestige Ultrasound System and a PA1-5A transducer. Data were cataloged for 3 different breathing conditions: quiet breathing, deep breathing, and sniffing. Intervention(s): not applicable Main Outcome Measure(s): Images were scored independently by three researchers on a three-point scale. Disagreements were resolved by a senior researcher. Main outcome measures included: percentage of viable images acquired for patients with a range of BMI scores, comparison of image viability between the three breathing conditions, percentage of compromised images for the right and left diaphragm. Result(s): BMI did not impact image quality (range: 19.8-37.7). The sniff test yielded the lowest percentage of unusable images (13%) compared to quiet breathing (17%) and deep breathing (21%). Moreover, the left diaphragm yielded a higher number of unmeasurable (92% percent of imaging errors were on the left side). No statistical significance was found in image usability scores between the 3 breathing conditions on either the right or left diaphragm. Conclusion(s): M-Mode imaging of the diaphragm is feasible;however, it is accompanied by user-, machine-, and patient-dependent challenges that appear to create more obstacles when imaging the left hemidiaphragm. A sniff test performed during M-mode US imaging is more likely to provide usable measurements of diaphragmatic function than other breathing conditions.