title: Validity and reliability of rectus femoris ultrasound measurements: Comparison of curved-array and linear-array transducers.
abstract: Muscle-mass loss augers increased morbidity and mortality in critically ill patients. Muscle-mass loss can be assessed by wide linear-array ultrasound transducers connected to cumbersome, expensive console units. Whether cheaper, hand-carried units equipped with curved-array transducers can be used as alternatives is unknown. Accordingly, our primary aim was to investigate in 15 nondisabled subjects the validity of measurements of rectus femoris cross-sectional area by using a curved-array transducer against a linear-array transducer-the reference-standard technique. In these subjects, we also determined the reliability of measurements obtained by a novice operator versus measurements obtained by an experienced operator. Lastly, the relationship between quadriceps strength and rectus area recorded by two experienced operators with a curved-array transducer was assessed in 17 patients with chronic obstructive pulmonary disease (COPD). In nondisabled subjects, the rectus cross-sectional area measured with the curved-array transducer by the novice and experienced operators was valid (intraclass correlation coefficient [ICC]: 0.98, typical percentage error [%TE]: 3.7%) and reliable (ICC: 0.79, %TE: 9.7%). In the subjects with COPD, both reliability (ICC: 0.99) and repeatability (%TE: 7.6% and 9.8%) were high. Rectus area was related to quadriceps strength in COPD for both experienced operators (coefficient of determination: 0.67 and 0.70). In conclusion, measurements of rectus femoris cross-sectional area recorded with a curved-array transducer connected to a hand-carried unit are valid, reliable, and reproducible, leading us to contend that this technique is suitable for cross-sectional and longitudinal studies.
authors.forename: Kendra
authors.initials: K
authors.lastname: Hammond
authors.forename: Jobby
authors.initials: J
authors.lastname: Mampilly
authors.forename: Franco A
authors.initials: FA
authors.lastname: Laghi
authors.forename: Amit
authors.initials: A
authors.lastname: Goyal
authors.forename: Eileen G
authors.initials: EG
authors.lastname: Collins
authors.forename: Conor
authors.initials: C
authors.lastname: McBurney
authors.forename: Amal
authors.initials: A
authors.lastname: Jubran
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Tobin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002983:Clinical Competence; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D015588:Observer Variation; D009929:Organ Size; D029424:Pulmonary Disease, Chronic Obstructive / Q000473:pathology / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000033:anatomy & histology* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015203:Reproducibility of Results; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation; D055815:Young Adult
keywords: COPD; critical illness myopathy; critical illness neuropathy; human muscle; intensive care unit; probe configuration; quadriceps femoris; reproducibility; sarcopenia; ultrasound imaging