Discrimination between malignant and benign thyroid tumors by diffusion-weighted imaging - A systematic review and meta analysis.

Purpose Magnetic resonance imaging is used to stage thyroid tumors. Diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) can be used to reflect tumor microstructure. Our aim was to compare ADC values of malignant and benign thyroid lesions based on a large sample. Methods MEDLINE library, EMBASE and SCOPUS databases were screened for the associations between ADC values and thyroid lesions up to August 2021. The primary endpoint of the systematic review were ADC values of benign and malignant thyroid lesions. In total, 29 studies were suitable for the analysis and were included into the present study. Results The included studies comprised a total of 2137 lesions, 1118 (52.3%) benign and 1019 (42.7%) malignant lesions. The pooled mean ADC value of the benign thyroid lesions was 1.88 × 10-3 mm2/s [95% CI 1.77-2.0] and the pooled mean ADC value of malignant thyroid lesions was 1.15 × 10-3 mm2/s [95% CI 1.04-1.25]. Conclusions ADC can well discriminate benign and malignant thyroid tumors. Therefore, DWI should be implemented into the presurgical diagnostic work-up in clinical routine.