Histopathological findings of human thyroid tumors and dynamic MRI.

Objective: Time intensity curves for gadolinium-diethylenetriaminepentaceticacid (Gd-DTPA) enhanced magnetic resonance imaging (MRI), namely dynamic MRI, were determined for thyroid diseases, and compared with findings of histopathologic examination.

Methods: Time intensity curves for the thyroid tumors were determined. Three different patterns of time intensity curves were observed: a rapid washout pattern, a delayed washout pattern and no change. Cell proliferating activities of thyroid tumors were estimated immunohistochemically by proliferating cell nuclear antigen (PCNA).

Results: In most of malignant diseases and a few benign diseases that had marked cell proliferative activity with showing more than 20% on labeling indexes of PCNA, the time intensity curve displayed the delayed washout pattern, in which intensity was above half-maximal value within 10 min after injection Gd-DTPA. Almost all benign diseases and a few well differentiated carcinomas displayed the rapid washout pattern, in which intensity was decreased to lower than half of peak grade within 10 min following injection and showed from 10 to 20% on labeling indexes of PCNA. Benign diseases that displayed no change of time intensity curve did not show PCNA positive cells.

Conclusion: These findings suggested that the time intensity curve obtained from dynamic MRI might indicate cell proliferating activity of thyroid tumors.