MR Pulse Sequences for Parathyroid Adenoma Imaging Using [¹⁸F]fluorocholine PET/MR in Primary Hyperparathyroidism

Area of Science:

• Radiology
• Medical Imaging
• Endocrinology

Background:

• Standardized magnetic resonance (MR) imaging protocols for parathyroid adenoma detection are lacking.
• Primary hyperparathyroidism (pHPT) diagnosis often requires precise localization of parathyroid adenomas.

Purpose of the Study:

• To evaluate the performance of different MR pulse sequences in visualizing histopathologically confirmed parathyroid adenomas.
• To compare T1-weighted fast spin echo (T1w FSE) and T2-weighted iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) flex water (T2w FSE flex water) sequences for parathyroid adenoma detection.

Main Methods:

• Retrospective analysis of 128 parathyroid adenomas in 110 patients with pHPT who underwent [18F]fluorocholine positron emission tomography (PET)/MR.
• Independent characterization of adenomas by two radiologists.
• Comparison of lesion conspicuity, delineation, and size on T1w FSE and T2w FSE flex water sequences.
• Statistical analysis using Cohen's kappa for interreader agreement and Wilcoxon signed-rank test for differences.

Main Results:

• Parathyroid adenomas showed significantly higher conspicuity, superior delineation, and larger size on T2w FSE flex water images compared to T1w FSE images (p < 0.001).
• These improvements were consistent for upper and lower pole adenomas.
• Ectopic adenomas did not show significant size differences between the two sequences (p = 0.646).

Conclusions:

• T2w FSE flex water sequences provide significantly better visualization of parathyroid adenomas than T1w FSE, particularly for orthotopic lesions.
• A limited MR protocol utilizing T2w FSE flex water is recommended for preoperative assessment in patients with pHPT undergoing PET/MR.