Skeletal Muscle Index and a Neuromuscular Blocking Agent

With the recent development of image analysis, it has become possible to measure the skeletal muscle index representing the subject's muscle mass from preoperative computed tomography (CT) images. Therefore, in this study, the investigators quantify the skeletal muscle index from preoperative CT images and analyze the correlation with the dose of neuromuscular blocking agent, rocuronium, required for maintaining deep neuromuscular blockade.

Inclusion Criteria: * Those who voluntarily agreed and signed the written consent form before participating in the study * American Society of Anesthesiologists physical class (ASA class) 1-3 * Patients scheduled for elective colon surgery under general anesthesia * Patients undergoing abdominal computed tomography for routine preoperative preparation Exclusion Criteria: * Pregnant women * Decreased renal function (GFR\