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. 2014 Jul 17;35(5):795–819. doi: 10.1210/er.2014-1026

Table 3.

Differential Diagnosis of Post-Styloid Retropharyngeal Masses: Imaging Features on MRI and Molecular Imaging

PGL Nodal Metastasis Schwannoma Neurofibroma
MRI Flow voids (salt-and-pepper appearance on T2-weighted images) Variable appearance on spin-echo images Moderate to high signal intensity on T2 Moderate to high signal intensity on T2
Central low signal on T2 may be seen (target sign)
Rapid (numerous arterial feeders), intense and homogeneous enhancement Heterogeneous enhancement Heterogeneous enhancement in large tumors with degenerative changes (cystic, pseudocystic) Moderate and delayed homogeneous enhancement
[18F]FDG Moderate to high uptake (highly elevated in SDHx-tumors) Low to high uptake depending on the primary tumor Low to high uptake (even in benign cases) Low uptake (high uptake values in malignant forms)
[18F]FDOPA High uptake No significant uptake No significant uptake No significant uptake
SST-based imaginga High uptake No significant uptake (possible high uptake in nodal metastases from thyroid cancers of follicular origin or nasopharyngeal cancers) No significant uptake No significant uptake
a

SST-based imaging is somatostatin receptor imaging with octreoscan or 68Ga-labeled somatostatin analogs.