| PRE | photoreacting enzyme; physician's report of examination; pigmented retinal epithelium; preplacement ... |
|---|---|
| PRR | proton relaxation rate; pulse repetition rate |
| RARE | rapid acquisition with relaxation enhancement |
| RRI | recurrent respiratory infection; reflex relaxation index; relative response index |
| RV-IVRT | right ventricular isovolumic relaxation time |