General interpretation and classification of risk in relation to global MBFR
| MBFR | Interpretation | Relative risk |
|---|---|---|
| >2 | Normal | Low |
| 1.7-2 | Mildly abnormal | Intermediate |
| 1.2—< 1.7 | Abnormal | High |
| <1.2 with a perfusion defect | Highly abnormal | Very high |
| <1.2 without a perfusion defect | Consider non-diagnostic study | Indeterminate |
Cutoffs are generally arbitrary and may vary slightly between labs, software used, stressors used, and published studies. The principle is that the lower the flow reserve the greater the relative risk