Intra- and interobserver variability in skeletal muscle measurements using computed tomography images

Area of Science:

• Radiology and Medical Imaging
• Body Composition Analysis
• Sarcopenia Research

Background:

• Sarcopenia, the loss of skeletal muscle mass and function, is linked to adverse health outcomes.
• Accurate body composition measurements are crucial for sarcopenia diagnosis, treatment monitoring, and complication prediction.
• Current methods often involve semi-automated analysis of axial images at the mid-lumbar level, which can be subjective.

Purpose of the Study:

• To evaluate the reproducibility of skeletal muscle area measurements using a semi-automated approach.
• To assess both intraobserver (within-observer) and interobserver (between-observer) variability.
• To identify potential sources of variability and propose methods for improvement.

Main Methods:

• Three radiologists performed repeated skeletal muscle measurements on a cohort of 29 patients.
• Intraobserver and interobserver reproducibility were statistically analyzed.
• The impact of slice selection on measurement variability was investigated.

Main Results:

• Good intraobserver agreement was observed, with a mean absolute difference of 0.98 cm².
• Measurement variability was primarily attributed to the selection of different image slices.
• Interobserver agreement was also good, with a minor bias noted in one observer's measurements.
• Averaging measurements from two slices showed a non-significant improvement over a single slice.

Conclusions:

• The described method for skeletal muscle area measurement demonstrates good reproducibility.
• Recommendations are provided to minimize variability in measurements.
• This approach supports reliable sarcopenia assessment in research and clinical settings.