Characteristic Dynamic Enhancement Pattern of MR imaging for Malignant Thyroid Tumor XIX Symposium Neuroradiologicum Division of Head & Neck radiology Department of Radiology Gachon University, Gil Medical Center Young Nam Park, M.D., Hee Young Hwang, M.D. Sung Hee Park, M.D., Hyung-Sik Kim, M.D.

BACKGROUND  Usually thyroid nodules are evaluated by scintigraphy, ultrasonography and percutaneous needle biopsy. Current diagnostic methods may not enable accurate detection of the malignant nature of a thyroid nodule, especially in multinodular goiter.  Therefore, new techniques are being investigated to improve the evaluation of thyroid nodules.  Dynamic contrast medium enhanced MRI is useful to differentiate malignant and benign lesions of pituitary gland, breast, and prostate gland. Introduction

PURPOSE  The purpose of this study was as follows : to determine the characteristic dynamic enhancement pattern of MR imaging for malignant thyroid tumor. Introduction

Study Population  The 8 patients were collected, who were pathology confirmed malignant thyroid tumor preoperatively. (F:M=7:1; mean, 55yrs; range, 22~81 yrs)  5 papillary carcinoma  1 medullary carcinoma  1 follicular carcinoma  1 FNAB proven atypical cell and multiple metastatic LNs in both neck  We got the approval from IRB (institutional review board approval) and obtained informed consent from patients for each study. M & M Study Population

 3.0-T MR imaging unit, Magnetom Verio (Siemens Medical Systems, Erlangen, Germany)  Axial T1-weighted MR images  Axial fast spin-echo T2-weighted MR image  Contrast agent-enhanced dynamic T1-weighted images  Subtraction image M & M Imaging Protocols

 Contrast agent-enhanced dynamic T1WI  dynamic spin-echo sequence  Images were obtained immediately after injection (as precontras scan) and at 1 min 30sec/ 3min/ 4 min 30 sec/ 6 min after injection of Gadovist.  axial planes with 0.7-mm slice thickness  a repetition time (TR) of 5.12 ms  an echo time (TE) of 1.99 ms M & M Imaging Protocols

 Compared to normal thyroid parenchyma Outcomes of dynamic enhancement pattern, thyroid cancer Dynamic enhancement pattern Patient numberPercentage (%) Delayed enhancement 4 papillary carcinoma 75% 1 medullary carcinoma 1 FNAB proven atypical cell Early strong enhancement 1 follicular carcinoma12.5% Persistently decreased enhancement 1 papillary carcinoma12.5% 8100%

Male/ 80 years old, FNAB proven atypical cell After injection 3 min 4 min 30 sec6 min1 min 30 sec

Female/ 69 years old Follicular carcinoma After injection 1 min 30 sec3 min4 min 30 sec6 min

After injection 1 min 30 sec3 min4 min 30 sec6 min Female/ 50 years old Papillary carcinoma

 Although this study has limitation of small patients population, the data suggest that delayed enhancement on enhanced dynamic T1WI is possible characteristic MR finding of malignant thyroid tumor Conclusion

Discussion  This may be because, in contrast to common cancers, but similar to other endocrine neoplasm such as pituitary and adrenal cortex tumours. angiogenesis is reduced in thyroid carcinoma compared with normal tissue. Conclusion