⁶⁸Ga-DOTATATE PET imaging in clinically non-functioning pituitary macroadenomas

Area of Science:

• Endocrinology
• Nuclear Medicine
• Oncology

Background:

• Clinically non-functioning pituitary macroadenomas (NFMA) are tumors that do not produce excess hormones.
• Previous studies on somatostatin receptor (SSTR) expression in NFMA have yielded inconsistent results.
• Existing detection methods like immunohistochemistry and 111In-DTPA-octreotide scintigraphy have limitations in sensitivity and specificity.

Purpose of the Study:

• To evaluate SSTR expression in NFMA using the advanced imaging technique 68Ga-DOTATATE PET.
• To compare the sensitivity of 68Ga-DOTATATE PET with previous methods for SSTR detection in NFMA.
• To assess in vivo SSTR expression in NFMA.

Main Methods:

• Thirty-seven patients with NFMA underwent 68Ga-DOTATATE PET/CT.
• Pituitary MRIs were co-registered with PET/CT scans.
• Somatostatin receptor expression was quantified by measuring the mean standardized uptake value (SUVmean) of 68Ga-DOTATATE, with SUVmean > 2 considered positive.

Main Results:

• 68Ga-DOTATATE PET/CT detected SSTR expression in 92% (34/37) of NFMA patients.
• The mean SUVmean in positive adenomas ranged from 2.1 to 12.4 (average 5.8 ± 2.6).
• This high detection rate suggests widespread SSTR expression in NFMA.

Conclusions:

• 68Ga-DOTATATE PET is a highly sensitive method for detecting in vivo SSTR expression in NFMA.
• The findings indicate that the majority of NFMA express SSTR.
• PET imaging offers superior sensitivity compared to traditional scintigraphy for assessing SSTR in NFMA.