Objectives

In follicular thyroid tumor, research has shown that evaluating blood flow within a tumor using ultrasound Doppler, specifically the Pulsatility Index (PI) and Resistance Index (RI) values, can help differentiate between benign and malignant tumors. This study aimed to clarify the pathological correlation between PI and RI values.

Methods

18 patients with follicular tumors were included. There were 9 cases each of follicular carcinoma and follicular adenoma. PI > 1.35 or RI > 0.78 was considered test-positive. Blocks were selected from each case and stained for CD31 and α-SMA. Ten different fields of view were set up per case, and the number of vessels stained in each was measured at the same location. To compare the number of mature vessels in the total number of vessels, the number of positive α-SMA staining was divided by the number of positive CD31 staining. Mean values were calculated from 10 different fields of view, and statistical analyses were performed.

Results

Both PI and RI were higher in follicular carcinoma. In follicular carcinoma cases, α-SMA/CD31 was 0.91, and in follicular adenoma cases, α-SMA/CD31 was 0.71, significantly higher in follicular carcinoma (p<0.001). In the follicular carcinoma, the positive and negative test groups were compared. In the positive group (5 cases), α-SMA/CD31 was 0.95, while in the negative group (4 cases), it was 0.85. The positive group exhibited values (p<0.01) than did the negative group. Next, we evaluated the correlation between PI and α-SMA/CD31 and between RI and α-SMA/CD31 in all 18 cases. We found a significant difference in the relationship between RI and α-SMA/CD31 (p<0.05).

Conclusion

We have shown that follicular carcinomas have significantly higher levels of α-SMA/CD-31 compared to follicular adenomas. We also found a correlation between PI and RI levels, which indicate vascular resistance, and the number of positive α-SMA levels.