FAIR true-FISP perfusion imaging of the thyroid gland

Purpose: To evaluate the feasibility of quantitative perfusion MRI of the thyroid gland using an arterial spin labeling (ASL) method.

Materials and methods: An ASL technique with flow-sensitive alternating inversion-recovery (FAIR) spin preparation and a true fast imaging in the steady state (TrueFISP) signal readout strategy was implemented on a 1.5T whole-body unit. Anatomical and perfusion imaging of the thyroid gland was performed in eight healthy volunteers and one patient with functioning adenoma. Quantitative perfusion maps were calculated using the extended Bloch equations.

Results: In all subjects the perfusion images showed diagnostic image quality. The mean examination time was 24 minutes for multiplanar perfusion imaging of the entire thyroid gland. Individual perfusion values ranged between 341 +/- 91 and 640 +/- 90 mL/100 g/minute, with a mean perfusion of 461 +/- 90 mL/100 g/minute. The functioning adenoma showed markedly reduced perfusion compared to normal thyroidal parenchyma. No perfusion was noticeable inside four detected thyroid cysts.

Conclusion: Quantitative ASL perfusion imaging of the thyroid gland using a FAIR-TrueFISP sequence leads to perfusion maps that may provide important information for assessing thyroid gland pathologies and monitoring therapeutic treatment.