Reliability of 2 ultrasonic imaging analysis methods in quantifying lumbar multifidus thickness

Area of Science:

• Musculoskeletal imaging
• Rehabilitation science
• Diagnostic accuracy

Background:

• Static rehabilitative ultrasound imaging (RUSI) for multifidus muscle thickness has established reliability.
• Video RUSI may enhance reliability by allowing optimal image selection.
• Measurement precision and reliability may be influenced by averaging multiple measures and low back pain (LBP) status.

Purpose of the Study:

• Compare within- and between-day intrarater reliability of static and video RUSI for multifidus muscle thickness.
• Evaluate measurement precision using averaged measures.
• Assess reliability in individuals with and without low back pain (LBP).

Main Methods:

• Compared static and video RUSI for multifidus muscle thickness in 27 volunteers (13 without LBP, 14 with LBP).
• Collected 3 static images and 3 video clips per session across 2 sessions (1-4 days apart).
• Assessed reliability and precision using ICC, SEM, MDC, bias, and 95% LoA.

Main Results:

• Averaging 2 measures optimized measurement precision for both static and video RUSI.
• No significant difference in reliability estimates between static and video RUSI across conditions.
• High reliability (ICC > 0.80) for multifidus thickness and percent change, with no significant differences between LBP and asymptomatic groups.

Conclusions:

• Both static and video RUSI provide high reliability for multifidus muscle measurements.
• Averaging two measures enhances measurement precision.
• Video RUSI is a reliable and efficient alternative to static RUSI for multifidus muscle assessment.