There are multiple definitions:
ultrafiltration rate(English)
- CKD, ESKD, GFR, HD, MTAC, PD, SAPD, SPA
- Kidney and adrenals, Nephrology
ultrasonic flow ratio(English)
- IVUS-derived FFR
- IVUS, FFR, PCI, QFR
- Coronary circulation, Ratio-based metric
- https://doi.org…IONS.120.009840