⁶⁸GA DOTATATE PET in Schwannomas: Distinct Avidity Pattern Supporting Noninvasive Diagnosis

Area of Science:

• Neuro-oncology
• Nuclear Medicine
• Radiology

Background:

• Schwannomas present as enhancing extra-axial masses, often mimicking other tumors on MRI.
• Contrast-enhanced MRI has limitations in differentiating small or atypical schwannomas.
• [Ga68]DOTATATE PET/MRI and PET/CT target somatostatin receptor 2 (SSTR2), useful for SSTR2-positive tumors like meningiomas.

Purpose of the Study:

• To characterize [Ga68]DOTATATE PET imaging features in patients with schwannomas.
• To evaluate the potential of [Ga68]DOTATATE PET in differentiating schwannomas from other SSTR2-expressing tumors.

Main Methods:

• Retrospective analysis of patients with MRI-diagnosed schwannomas who underwent [Ga68]DOTATATE PET/MRI or PET/CT.
• Measurement of lesion maximum standardized uptake values (SUV) and SUV ratios relative to the superior sagittal sinus (SUVRSSS).

Main Results:

• Sixteen patients (mean age 62.1 years) with schwannomas were included.
• All schwannomas showed minimal [Ga68]DOTATATE avidity (mean SUV 1.6 ± 0.7, mean SUVRSSS 1.5 ± 0.7).
• These uptake values were significantly lower than established thresholds for meningioma diagnosis.

Conclusions:

• Schwannomas exhibit low [Ga68]DOTATATE avidity.
• [Ga68]DOTATATE PET can help non-invasively distinguish schwannomas from SSTR2-expressing tumors with similar MRI appearances.
• This imaging modality can aid in diagnostically challenging cases involving skull base and neck masses.