Excellent reliability for MRI grading and prognostic parameters in acute hamstring injuries.

Area of Science:

• Radiology
• Sports Medicine
• Musculoskeletal Imaging

Background:

• MRI parameters and categorical grading are used to predict hamstring injury outcomes.
• Reliability and smallest detectable difference (SDD) of these MRI measures were previously unevaluated.
• Variability in results may stem from reporting differences rather than actual injury status.

Purpose of the Study:

• To evaluate the interobserver and intraobserver reliability of MRI grading and prognostic parameters for hamstring injuries.
• To determine the smallest detectable difference (SDD) for these MRI measures.
• To establish confidence in MRI-based assessments for hamstring injuries.

Main Methods:

• Two radiologists assessed 25 hamstring injuries using Peetrons grading and specific MRI parameters (distance, extent, cross-sectional area, volume).
• Interobserver and intraobserver reliability were calculated.
• Smallest detectable differences (SDD) were determined for each variable.

Main Results:

• Grading distribution: 3 Grade 0 (12%), 11 Grade 1 (44%), 9 Grade 2 (36%), 2 Grade 3 (8%).
• Excellent reliability for grading (Cronbach's α: interobserver 1.00, intraobserver 0.96).
• High reliability for prognostic MRI parameters (ICC: 0.77–1.0), with varying SDDs.

Conclusions:

• High interobserver and intraobserver reliability for MRI grading and prognostic parameters in acute hamstring injuries.
• Scoring hamstring injuries by experienced radiologists is reproducible in clinical practice and research.
• Documented SDDs enable meaningful clinical inferences from changes in MRI status.