Preoperative Evaluation of Sellar and Parasellar Macrolesions by [¹⁸F]Fluorodeoxyglucose Positron Emission Tomography

Various diseases can occur in the sellar and suprasellar regions. The potential of [¹⁸F]fluorodeoxyglucose (FDG) positron emission tomography (PET) for the preoperative evaluation of sellar and parasellar lesions was investigated.

A total of 49 patients aged 8-82 years with sellar and parasellar macroscopic lesions (≥10 mm) underwent FDG PET. Twenty-two patients had pituitary adenomas, including 14 nonfunctioning and 8 growth hormone-secreting adenomas. Eleven patients had craniopharyngiomas, including 5 adamantinomatous and 6 squamous-papillary types. Eight patients had chordoma, 4 had meningioma, and 4 had a Rathke cleft cyst. The maximum standardized uptake value (SUV_max), and the ratio of the SUV_max in the tumor to the mean standardized uptake value in the normal cortex (T/N ratio) or in the normal white matter (T/W ratio) were calculated. The relationships between SUV_max, T/N ratio, and T/W ratio, and lesion disease were evaluated.

Uptakes of FDG, including SUV_max, T/N ratio, and T/W ratio, were lower in chordoma and Rathke cleft cyst compared with pituitary adenoma. SUV_max, T/N ratio, and T/W ratio of nonfunctioning adenoma were significantly higher than those of growth hormone-secreting adenoma. SUV_max, T/N ratio, and T/W ratio of squamous-papillary type were significantly higher than those of the adamantinomatous type of craniopharyngioma.

FDG PET is useful for the preoperative diagnosis of sellar and parasellar macrolesions. High uptake in nonfunctioning pituitary adenoma, and low uptake in chordoma are significant. The difference in FDG uptake dependent on the histologic subtype may be related to the specific genetics of the craniopharyngioma subtype.