Early evaluation of ~(131)I nuclide therapeutic effect in Graves' disease patients by MRI

Objective: To evaluate the early effect of 131I nuclide therapy in Graves' disease by MRI. Materials and Methods: MRI was performed in 18 GD patients before and at 1, 3 months after 131I nuclide therapy respectively. According to the follow-up thyroid function laboratory results at 3 months, the enrolled GD patients were divided into effective group(n=9) and ineffective group(n=9). Overall thyroid volume and apparent diffusion coefficient(ADC) values were measured blindly and the changes of volumes and ADCs were compared longitudinally in both groups. Results: Compared with GD patients before 131I nuclide therapy, the thyroid volume decreased significantly in effective group(P0.01) in the patients one month after therapy, while there was no change in ineffective group(P=0.07), and there was no change for the average thyroid ADC values in both groups(P=0.54, 0.27). The thyroid volume decreased significantly in both effective group(P0.01) and ineffective group(P0.05) in GD patients three months after therapy compared with patients before therapy; the average thyroid ADC values decreased in effective group(P0.05), however, there was no change in ineffective group(P=0.46). The thyroid volume decreased significantly in effective group(P0.05) but there was no change in ineffective group(P=0.20) three months after therapy compared with that of one month after therapy, and there was no change for the average thyroid ADC values in both groups(P=0.53, 0.08) between three and one months after therapy. Conclusion: The overall thyroid volume and the average ADC values could demonstrate early response after 131I nuclide therapy in Graves' disease patients.