Introduction
Pitfalls on PSMA- and SSTR-targeted PET/CT
Pitfalls on PSMA-targeted PET/CT
Pitfalls on SSTR-PET/CT
Imaging agents | PSMA | SSTR |
---|---|---|
Normal biodistribution | Lacrimal glands Salivary glands Liver Spleen Kidneys Small bowel Ganglia | Pituitary gland Major salivary glands Thyroid Adrenal glands Liver Spleen Pancreatic uncinate process Splenosis, splenunculi Radiotracer excretion via urinary tract [20] |
Important pitfalls | Benign pathologies mimicking PCa Benign bone diseases Benign tumors of neurogenic origins Hemangiomas [34] and benign soft-tissue pathologies PSMA-avid tumor entities other than PCa | Inflammatory diseases Degenerative bone structures [20] Vertebral hemangioma [50] Rare NET tumors Medullary thyroid carcinoma [51] Paraganglioma and pheochromocytoma [52] Non-NET tumors |
Introduction of MI-RADS: two reciprocal framework systems for PSMA- and SSTR-PET/CT interpretation
MI-RADS
PSMA-RADS
SSTR-RADS
MI-RADS classification | Workup | Uptake levela | PRRT/PRLT? | ||
---|---|---|---|---|---|
1 | 1A | Benign lesion, characterized by biopsy or anatomic imaging without abnormal uptake | n/a | 1 | N |
1B | Benign lesion, characterized by biopsy or anatomic imaging with abnormal uptake | n/a | 2–3 | N | |
2 | Soft-tissue site or bone lesion atypical for metastatic PCa or NET | n/a | N | ||
3 | 3A | Equivocal uptake in soft-tissue lesion typical of PCa or NET | B, F/U | 1–2 | N |
3B | Equivocal uptake in bone lesion not atypical of PCa or NET | B, F/U | 1–2 | Nb | |
3C | Intense uptake in site highly atypical of all but advanced stages of PCa or NET (i.e., high likelihood of nonprostatic/non-NET malignancy or other benign tumor) | B | 3 | N | |
3D | Lesion suggestive of malignancy on anatomic imaging but lacking uptake. For SSTR-RADS: 2-deoxy-2-[18F]-fluoro-D-glucose [18F]-FDG is recommended to rule out potential dedifferentiation of a single lesion | B, F/U | Not available | Nb | |
4 | Intense uptake in site typical of PCa or NET but lacking definitive findings on conventional imaging | n/a | 3 | Y | |
5 | Intense uptake in site typical of PCa or NET but with definitive findings on conventional imaging | n/a | 3 | Y |
PSMA-PET/CT | SSTR-PET/CT | |
---|---|---|
Patient’s history | Date of tumor biopsy Date of primary diagnosis Previous therapies Previous conventional or functional imaging History and treatment of other malignancies | |
Laboratory test results (PSA) Gleason score | Primary tumor origin Laboratory test results (CgA, NSE) Ki67/proliferation index Previous [18F]-FDG scans | |
Imaging data | Injected amount/activity Uptake time Field of view |