No abstract

Objectives: We undertook a systematic review and meta-analysis of the diagnostic performance of mean apparent diffusion coefficient (ADC) values derived by diffusion-weighted (DW)-MRI in the characterization of solid benign and malignant liver lesions, and to assess their value in discriminating these lesions in daily routine practice. Methods: A systematic review of PubMed, Embase, Scopus, and Web of Science was conducted to retrieve studies that used ADC values for differentiating solid benign/dysplastic nodules and malignant liver lesions. A bivariate random-effects model with pooled sensitivity and specificity values with 95% CI (confidence interval) was used. This meta-analysis was performed on the per-lesion basis. Summary receiver operating characteristic (SROC) plot and area under curve (AUC) were created. Results: A total of 14 original articles were retrieved. The combined (95% CI) sensitivity and specificity of mean ADC values for differentiating solid benign from malignant lesions were 78% (67 to 86%) and 74% (64 to 81%), respectively. The pooled (95% CI) positive and negative LRs were respectively 3 (2.3 to 3.8) and 0.3 (0.21 to 0.43). The DOR (95% CI) was 10 (7 to 15). The AUC (95% CI) of the SROC plot was 82% (78 to 85%). Reporting bias was negligible (P value of regression test = 0.36). Mean size of malignant lesions and breathing pattern of MRI were found to be sources of heterogeneity of pooled sensitivity. Conclusion: ADC measurement independently may not be an optimal diagnostic imaging method for differentiating solid malignant from solid benign hepatic lesions. The meta-analysis showed that ADC measurement had moderate diagnostic accuracy for characterizing solid liver lesions. Further prospective and comparative studies with pre-specified ADC thresholds could be performed to investigate the best MRI protocol and ADC threshold for characterizing solid liver lesions. Advances in knowledge: ADC measurement by DW-MRI does not have a good diagnostic performance to differentiate solid malignant from solid benign lesions. Therefore, we suggest not using ADC values in clinical practice to evaluate solid liver lesions.

We intended to compare gray-scale vs. color Doppler ultrasound findings in cold thyroid nodules. Sixty-four patients with cold thyroid nodules for whom the presumptive diagnosis of malignancy (based on isotope scan study) had been made were consecutively included. They underwent gray-scale and color Doppler sonography studies. Based on histopathologic examination of surgically removed nodules, there were respectively 25 (39%) and 39 (61%) malignant and benign nodules. On color Doppler sonography, preference central hypervascularity was the most common finding in malignant nodules (17 nodules, 68%). Among benign nodules, preference perinodular hypervascularity was the most common finding (26 nodules, 66.7%). The most sensitive and specific Doppler sonography findings for malignant nodules were preference central hypervascularity (68%) and only central vascularity (97%), respectively. On gray-scale sonography, absent halo sign was the most common finding in malignant nodules (20 nodules, 80%). Among benign nodules, microcalcification was the most common finding which was reported in 12 nodules (30.7%). Hypoechogenicity was the most specific finding (76.9%) for malignant nodules. Since both gray-scale and color Doppler ultrasonography are inexpensive, non-invasive, and accessible methods to diagnose thyroid malignant cold nodules, it is recommended that these methods be applied by clinicians to assist or even substitute other invasive methods.