Table 3 Summary of the ‘added value’ features of PET–CT compared to conventional imaging (MRI and CT)
Reasons for added value of PET–CT over conventional imaging | Number of PET–CT scans per indication | ||
|---|---|---|---|
Stagingb | Restaginga | Treatment response | |
Occult bone metastases | 10 | 3 | 1 |
Recurrence at local site or adjacent to metallic prosthesis not definitive on conventional imaging | 0 | 18 | 2 |
Follow up of occult bone metastases | 0 | 8 | 10 |
Occult muscular metastases | 3 | 0 | 0 |
Follow up of occult muscular metastases | 0 | 3 | 2 |
Cardiac metastases (muscular) not detected on conventional imaging | 2 | 1 | 0 |
Subcentimetre FDG avid nodes | 5 | 2 | 1 |
Static tumoural size, reduced FDG avidity | 0 | 7 | 16 |
Static tumoural size, increased FDG avidity | 6 | 2 | 6 |
Solitary FDG avid pulmonary nodule, indeterminate on CT | 7 | 3 | 0 |
Missed visceral disease on CT/MRI | 11 | 5 | 5 |
Metastasis outside the fields of conventional imaging | 1 | 0 | 0 |
FDG negative suspected recurrence adjacent to prosthesis or locally in patient with prior markedly avid disease | 0 | 3 | 2 |
Intra-lesional heterogeneity—guided biopsy to avoid underestimation of grade | 10 | 6 | 0 |
Enlarged FDG negative nodes with moderately FDG avid primary | 1 | 2 | 0 |
Increase in tumoural size but reduced avidity | 0 | 0 | 7 |
Recurrence at an ablation or surgical site, indeterminate on MRI | 0 | 2 | 0 |
Follow up of FDG positive disease adjacent to prosthesis or local surgical site | 0 | 13 | 7 |
Total | 56 | 78 | 59 |