Purpose:

To assess the diagnosis, activity and clinical course of Graves and Hashimato diseases with diffusion weighted echoplanar magnetic resonance(MR) imaging.

Methods and Materials:

Between May 2007 and February 2008 ,51 consecutive patient with oto-immune thyroid diseases (22 Graves disease and 29 Hashimato disease ) and 14 healty subjects underwent diffusion weighted MR imaging ,by using T1-, T2 and single shot spin echo, echo pla-nar imaging.The study was performed by using the following b factors of 200 and 400 second/ mm2 and the apparent diffusion coefficient (ADC) values of the thyroid gland were calculated.

Results:

The ADC values obtained with b factor of 200 second/mm2 from the diffusion weighted images of the patients with Graves disease was significantly higher than patients of Hashimo-to disease (p < 0,005).The ADC values obtained with b factor of 400 mm2/sn from the diffusion weighted images of the patients with Graves disease and healty volunteers was significantly higher than patients of Hashimoto disease(p < 0,01).There was no significant difference between hyperthyroid and euthyroid patients with Graves disease in the ADC values obtained with both 200 and 400 second/mm2 (p values following 0,259 and 0,880).There was no significant difference between hyperthyroid ,hypothyroid and euthyroid patients with Hashimoto disease in the ADC values obtained with both 200 and 400 second/mm2(p values following 0,076 and 0,075).

Conclusion:

The ADC values of thyroid gland in autoimmun thyroid diseases are valuable in dif-ferantial diagnosis of Graves disease and Hashimoto disease.

Keywords: Diffusion MRI, Autoimmune Thyroid Diseases,ADC