# [68Ga]Ga-DOTATATE PET/CT and PET/MR enhances the detection of pituitary ACTH-secreting adenomas in cushing’s disease

## TL;DR

[68Ga]Ga-DOTATATE PET/CT and PET/MR are more effective than dynamic MR in locating pituitary tumors causing Cushing's disease.

## Contribution

Demonstrates the superior diagnostic performance of [68Ga]Ga-DOTATATE PET/CT and PET/MR over dynamic MR in detecting ACTH-secreting pituitary adenomas.

## Key findings

- [68Ga]Ga-DOTATATE PET had 100% sensitivity in detecting ACTH-secreting pituitary adenomas.
- Combining PET with functional tests achieved 100% specificity in diagnosing Cushing's disease.
- G-SUVmax from PET/MR showed the highest diagnostic accuracy (AUC 1.0).

## Abstract

This study aimed to evaluate the diagnostic performance of [68Ga]Ga-DOTATATE PET/CT or PET/MR in comparison to dynamic MR (dMR) in locating ACTH-secreting pituitary adenomas in Cushing's disease (CD). The utility of PET and MR semi-quantitative parameters was additionally explored as non-invasive biomarkers for tumor characterization.

Aretrospective analysis was conducted in 14 patients with CD and 16 controls with ectopic ACTH syndrome. Surgical pathology and post-operative follow-up served as reference standard. All patients underwent [68Ga]Ga-DOTATATE PET/CT or PET/MR, dMR; some also underwent [18F]F-FDG PET. Imaging interpretation included visual and semi-quantitative (SUVmax and ADCmin) assessment.

[68Ga]Ga-DOTATATE PET demonstrated a 100% sensitivity indetecting ACTH-secreting pituitary adenomas, superior to dMR with a sensitivity of 85.7%. [18F]F-FDG PET showed a sensitivity of 80%. Combining [68Ga]Ga-DOTATATE PET with functional tests (high dose dexamethasone-suppression test and/or inferior petrosal sinus sampling) achieved specificity up to 100%, whereas the specificity of PET alone was only 50% due to pituitary structural abnormalities. Semi-quantitative analysis confirmed significantly reduced [68Ga]Ga-DOTATATE SUVmax and ADCmin in adenomas. Diagnostic efficacy ranked as follows: G-SUVmax from PET/MR was optimal (AUC1.0), followed by ADCmin (AUC 0.96) and G-SUVmax from PET/CT (AUC 0.87).

G-SUVmax and ADCmin can be used as reliable diagnostic predictors. [68Ga]Ga-DOTATATE PET/MR may facilitate the preoperative localization of CD.