Tutorial: A Step‐by‐Step Guide (Version 2.0) for Measuring Abdominal Circumference and Skeletal Muscle From a Single Cross‐Sectional Computed‐Tomography Image Using the National Institutes of Health ImageJ

Background In patients with acute and chronic illness, depleted skeletal muscle (SM) mass, also referred to as sarcopenia, is a condition associated with an underlying disease process and adverse outcomes. Because of software upgrades and errors related to installation, clarifications and a revised tutorial were needed for calculating SM cross‐sectional area (CSA) using the National Institutes of Health (NIH) ImageJ. Methods A pilot study was conducted to determine the usability of the tutorial version 2.0. Eight adults (≥18 years of age) who had no previous experience or background in body composition or computed‐tomography imaging and owned a personal laptop computer (Mac or PC) were included in the pilot study. Participants were tested on the completion of 4 tasks: (1) installation of software, (2) updating the software, (3) following revised tutorial (version 2.0), and (4) transferring information from the software to a spreadsheet for calculation of SM CSA. Results All participants completed the tutorial and all assigned tasks, 4/4 (100%). However, 38% (3/8) of the participants made errors while cutting and pasting values from the ImageJ results box to a spreadsheet for calculating SM CSA. Conclusion The tutorial version 2.0 was easy to follow and provided sufficient information for adults to install, update, and perform the steps of body composition for the NIH ImageJ software without major issues. Care should be taken when cutting and pasting results from the software as well as when using the Microsoft Excel spreadsheet for calculating SM CSA.