Table 5. Interpretation of 99mTc-pyrophosphate scintigraphy.
| Visual grading | |
| The relative tracer uptake in the myocardium to ribs seen on planar and SPECT images is graded on the following scale: | |
| • Grade 0 | No myocardial uptake and normal bone uptake |
| • Grade 1 | Myocardial uptake less than rib uptake |
| • Grade 2 | Myocardial uptake equal to rib uptake |
| • Grade 3 | Myocardial uptake greater than rib uptake with mild/absent rib uptake |
| H/CL ratio interpretation | |
| • 1-hour images | H/CL ratio > 1.5 |
| • 3-hour images | H/CL ratio ≥ 1.3 |
| Conclusions | Components | ||
| Visual Score (Grade) | H/CL ratio at 1-hour | H/CL ratio at 3-hour | |
| Not suggestive | 0 | < 1 | < 1.3 |
| Strongly suggestive | 2 or 3 | > 1.5 | ≥ 1.3 |
| Equivocal | 1 | 1-1.5 |