Ultrasound Measures of the Lumbar Multifidus: Effect of Task and Transducer Position on Reliability
Bibliographic record
Abstract
OBJECTIVE: To (1) assess the intra- and inter-rater reliability of different ultrasound (US) measures of the lumbar multifidus muscle in subjects with and without chronic low back pain and (2) test 3 different ways to enhance reliability, that is, by testing different tasks, using a template, and averaging trials within or between days. DESIGN: Cross-sectional repeated-measures design. SETTING: Laboratory setting. PATIENTS: Fifteen subjects with chronic low back pain and 15 control subjects. METHODS: Subjects (n = 30) performed contralateral arm lifting and contralateral leg lifting while in the prone position. Two 7-second videos of the lumbar multifidus (from rest to contraction) were collected with and without a template (transparency) to reposition the transducer on the skin. One of the two raters repeated the testing 7 to 14 days later to assess intrarater reliability in addition to inter-rater reliability. Reliability was assessed with the generalizability theory as a framework. MAIN OUTCOME MEASUREMENTS: US imaging measures of the lumbar multifidus thickness were obtained in patients at rest and during standardized contractions (hereafter called primary measures) at 2 vertebral levels and on both sides. These primary measures were used to calculate different, potentially useful US parameters (hereafter called derived measures). RESULTS: Intrarater reliability was better than inter-rater reliability, and primary measures were more reliable than derived measures. The tasks investigated showed comparable reliability results, and the use of the transducer position template was not effective to increase reliability. Averaging the measures of 3 images increased reliability substantially. CONCLUSIONS: Optimal reliability requires the use of a single rater and the averaging of at least 3 images per visit. In these conditions, primary measures reach acceptable levels of reliability, which was more difficult to achieve for most derived measures. Arm or leg lifting tasks showed similar reliability, and thus the arm-lifting task is recommended for comparisons with previous studies. The use of a transducer position template is not recommended.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".