Article Figures & Data
Figures
- FIG 1.
ROC curves for the performance of PET/MR imaging–based NI-RADS for discriminating treatment failure or no treatment failure. Blue curves reflect the performance of PET/MR imaging for the primary site, neck lymph nodes, and all sites combined. Inflection points in the curves are discrimination points between NI-RADS 1 and 2 and 2 and 3. The red diagonal curve is a reference. The AUC is reported for each curve, with values >0.500 signifying good performance of the test to discriminate treatment failure.
- FIG 2.
Conspicuity of disease recurrence with PET/MR imaging. Coronal T1WI post gadolinium (A) shows subtle enhancement along the right soft palate (arrow) in a patient with history of treated SCC. Fused coronal PET/MR imaging (B) demonstrates avid FDG uptake at the area of enhancement (arrow), which was recurrent SCC on biopsy and subsequently treated with wide local excision. Postresection axial T1WI postgadolinium sequence (C) shows ill-defined enhancement in the right oropharynx (arrow) with corresponding avid FDG uptake (D), which was biopsy-proved as SCC.
- FIG 3.
PET/MR imaging to evaluate perineural spread of adenoid cystic carcinoma. Coronal T1WI postgadolinium (A) and coronal fused PET/MR imaging (B) of a patient with a history of left maxillary sinus adenoid cystic carcinoma status post resection and radiation. On this initial posttreatment PET/MR imaging, the enhancing tissue along the thickened extraocular muscles (arrow) and infraorbital foramen (dashed arrow) of the left orbit corresponds to areas of increased FDG uptake and increased metabolic activity. The site was scored as NI-RADS 3 at consensus. The patient underwent orbital exenteration, with surgical pathology positive for perineural spread of tumor.
- FIG 4.
Interreader variability in the interpretation of PET/MR imaging–based NI-RADS. Axial T1WI postgadolinium sequence (A) and axial fused PET/MR imaging (B) in a patient with a history of maxillary sinus SCC status post subtotal maxillectomy and radiation. On the initial posttreatment PET/MR imaging, enhancing tissue in the pterygopalatine fossa (arrow) does not have corresponding FDG uptake. This primary site finding was scored a 2 by 1 reader (for discordant PET and MR imaging findings) and as a 1 by the other reader (for expected treatment related change). The patient has no evidence of recurrence on follow-up imaging nor clinical evidence of recurrence. In these scenarios, although agreement may not be perfect, the linked NI-RADS management decision of “short interval follow-up” allows these patients to be correctly risk-stratified.
Tables
PET/MR Imaging NI-RADS Score No. Sites Failure P Value Primary site 43 18 (41.9%) <.001 1 19 2 (10.5%) 2 12 5 (41.7%) 3 12 11 (91.7%) Neck lymph nodes 43 5 (11.6%) <.001 1 33 0 (0.0%) 2 6 1 (16.7%) 3 4 4 (100%) Combined sites 86 23 (26.7%) <.001 1 52 2 (3.8%) 2 18 6 (33.3%) 3 16 15 (93.8%) - Table 2:
Receiver operating characteristic AUC values for PET/MR imaging NI-RADS performance
ROC Curve AUC 95% CI P Value SCC vs non-SCC subgroups NI-RADS 1° site vs 1° failure (SCC) 0.867 0.688–1.000 .007 NI-RADS 1° site vs 1° failure (non-SCC) 0.856 0.685–1.000 .004 NI-RADS LN vs LN failure (SCC) 1.000 1.000–1.000 .024 NI-RADS LN vs LN failure (non-SCC) 0.968 0.889–1.000 .010 PET/MR imaging NI-RADS by reader Reader A 1° site vs 1° failure 0.853 0.729–0.977 <.001 Reader B 1° site vs 1° failure 0.866 0.747–0.985 <.001 Reader A LN vs LN failure 0.951 0.890–1.000 <.001 Reader B LN vs LN failure 0.963 0.910–1.000 <.001 MRI only NI-RADS by reader Reader A 1° site vs 1° failure 0.821 0.673–0.970 <.001 Reader B 1° site vs 1° failure 0.703 0.540–0.867 .021 Reader A LN vs LN failure 0.768 0.533–1.000 .052 Reader B LN vs LN failure 0.900 0.689–1.000 .004 Note:—1° indicates the primary site; LN, lymph node.
