FIGURE 4.

Example of different SSTR-RADS classifications of experienced readers vs. inexperienced readers. Images are from 49-y-old woman undergoing restaging for pancreatic neuroendocrine neoplasia. (A) ⁶⁸Ga-DOTATOC maximum-intensity projection demonstrated intense radiotracer uptake in thyroid (arrowhead), liver (double arrow), and celiac (single arrow) and mesenteric (star) LNs. (B–D) Axial CT (B), ⁶⁸Ga-DOTATOC PET (C), and ⁶⁸Ga-DOTATOC PET/CT (D) showed intense SSTR expression in left lobe of thyroid (arrowhead), which was rated as SSTR-RADS-3C by experienced readers and as SSTR-RADS-1 by inexperienced readers. SSTR-RADS-3C describes lesions with intense radiotracer accumulation in sites highly atypical of NENs, and thus, these lesions are suggestive of SSTR-expressing, non-NEN benign tumor. Fine-needle aspiration biopsy of nodule revealed no abnormality. (E–G) Axial CT (G), ⁶⁸Ga-DOTATOC PET (F), and ⁶⁸Ga-DOTATOC PET/CT (G) demonstrate intense uptake in liver (double arrows) and celiac LN (single arrow), with no corresponding finding on CT. These lesions were rated as SSTR-RADS-4 by all readers. (H–J) Axial CT (H), ⁶⁸Ga-DOTATOC PET (I), and ⁶⁸Ga-DOTATOC PET/CT (J) show intense uptake in mesenteric LN (star). Given the corresponding finding on CT, this lesion was classified SSTR-RADS-5 by all observers. All readers recommended PRRT. ER = experienced readers; IR = inexperienced readers.