Half subtraction has higher CJV and SNR rank AUC than full subtraction for MR-ART motion scans with grades 2 and 3.

This fixed sensitivity analysis compares raw MRIQC scores with subtraction of 0.5 or 1 times each participant's standard-scan reference in OpenNeuro MR-ART ds004173 v1.0.2. The grade-rank comparison includes 278 motion scans from 147 participants, with grades 2 and 3, across HM1 and HM2; these conditions use five and ten head-nod instructions and do not measure head movement. The two conditions have equal weight in the mean. Half subtraction gives higher mean rank AUC than full subtraction for CJV (0.803759 vs 0.768333) and total SNR (0.840003 vs 0.783334). For EFC, half subtraction is higher than raw (0.785530 vs 0.717721) and lower than full subtraction (0.828291). The 95% pointwise participant-bootstrap interval for half minus full is [0.011973, 0.061423] for CJV, [-0.110832, 0.024260] for EFC, and [0.022721, 0.092644] for total SNR. The interval for EFC and the intervals for half minus raw CJV and SNR include zero. These intervals have no multiple-comparison adjustment. The analysis does not establish equivalent performance, an optimized weight, or a clinical rule. It uses one scanner and protocol, grades 2 and 3 only, and data used in earlier metric selection; there is no external test sample. The supplied metrics were not recalculated from images.

MR-ART · MRI · image quality · motion artefacts · reference subtraction · rank AUC · bootstrap · CJV · EFC · signal-to-noise ratio