Thyroid Imaging Reporting and Data System Reduces Biopsies

Criteria from the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) offers a meaningful reduction in the number of thyroid nodules recommended for biopsy, according to a study published in the journal Radiology. 

Researchers from several states performed a retrospective study to compare the biopsy rate and diagnostic accuracy before and after applying ACR TI-RADS criteria for thyroid nodule evaluation. Eight radiologists with three to 32 years of experience in thyroid ultrasonography were asked to review the ultrasound features of 100 thyroid nodules that were cytologically proven and/or pathologically proven. Nodules evaluated in five US categories and biopsy recommendations were provided based on the radiologists’ practice patterns without knowledge of ACR TI-RADS criteria. Three other expert radiologists were reference standard readers for the imaging findings. ACR TI-RADS criteria were retrospectively applied to the features assigned by the eight radiologists to produce biopsy recommendations. Comparison was made for biopsy rate, sensitivity, specificity, and accuracy.

The results showed 15 of the 100 nodules (15 percent) were malignant. The mean number of nodules recommended for biopsy by the eight radiologists was 80 ± 16 (standard deviation) based on their own practice patterns and 57 ± 11 with retrospective application of ACR TI-RADS criteria.

Without ACR TI-RADS criteria:
Sensitivity  95 percent
Specificity  20 percent
Accuracy  28 percent

With ACR TI-RADS criteria:
Sensitivity 92 percent
Specificity 44 percent
Accuracy 52 percent

Expert consensus:
Sensitivity 87 percent
Specificity 51 percent
Accuracy 56 percent

The researchers noted that although fewer malignancies were recommended for biopsy with ACR TI-RADS criteria, the majority met the criteria for follow-up US. Only three of 120 (2.5 percent) malignancy encounters required no follow-up or biopsy. Expert consensus recommended biopsy in 55 of 100 nodules with ACR TI-RADS criteria.

Not only did the ACR TI-RADS criteria offer a meaningful reduction in the number of thyroid nodules recommended for biopsy, the researchers wrote, they significantly improve the accuracy of recommendations for nodule management.