Diagnostic Performance of Technetium-99m Methoxy-Isobutyl-Isonitrile for Differentiation of Malignant Thyroid Nodules: A Systematic Review and Meta-Analysis

Background: The purpose of the current study was to investigate the diagnostic performance of technetium-99m (Tc-99m) methoxy-isobutyl-isonitrile (MIBI) for differentiation of malignant thyroid nodules (TN) through a systematic review and meta-analysis.

Methods: The MEDLINE/PubMed and EMBASE database, from the earliest available date of indexing through January 31, 2018, were searched for studies evaluating the diagnostic performance of Tc-99m MIBI for TN. The sensitivities and specificities were determined across studies, positive and negative likelihood ratios (LR+ and LR-) were calculated, and summary receiver operating characteristic curves were constructed.

Results: Across 22 studies (2421 patients), the pooled sensitivity for Tc-99m MIBI thyroid scan was 0.87 [confidence interval (CI) 0.76-0.93] with heterogeneity (I² = 92.3) and a pooled specificity of 0.78 [CI 0.67-0.86] with heterogeneity (I² = 96.4). LR syntheses gave an overall LR+ of 4.0 [CI 2.5-6.3] and LR- of 0.17 [CI 0.09-0.32]. The pooled diagnostic odds ratio was 24 [CI 63-176]. The hierarchical summary receiver operating characteristic curve indicates that the area under the curve was 0.90 [CI 0.87-0.92]. In meta-regression analysis, no definite variable was the source of the study heterogeneity.

Conclusion: The current meta-analysis shows a moderate sensitivity and specificity of Tc-99m MIBI thyroid scan for differentiation of malignant TN. However, the diagnostic odds ratio was relatively low and the LR scattergram indicated that Tc-99m MIBI thyroid scan is not useful for confirming the presence of malignant TN or for its exclusion. Therefore, Tc-99m MIBI thyroid scans should be used restrictively and interpreted cautiously when assessing TN for malignancy.

Tc-99m MIBI; nodules; thyroid; thyroid cancer.