Diagnostic precision of nanoparticle-enhanced MRI for lymph-node metastases: a meta-analysis

SummaryBackgroundAt present, there is no accepted, ideal imaging modality or technique for diagnosis of lymph-node metastases. We aimed to assess the diagnostic precision of MRI with ferumoxtran-10—an ultrasmall superparamagnetic iron-oxide nanoparticle used as a contrast agent for diagnosis of lymph-node metastases, compared with that of unenhanced MRI and final histological diagnosis.MethodsWe did a meta-analysis of prospective studies that compared MRI, with and without ferumoxtran-10, with histological diagnosis after surgery or biopsy. Sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated for every study; summary receiver operating characteristic (ROC) and subgroup analyses were done; and study quality and heterogeneity were assessed. Metaregression analysis was used to analyse the effect of ferumoxtran-10 in diagnostic precision of MRI.FindingsSummary ROC curve analysis for per-lymph-node data showed an overall sensitivity of 0·88 (95% CI 0·85–0·91) and overall specificity of 0·96 (0·95–0·97) for ferumoxtran-10-enhanced MRI. Overall weighted area under the curve for ferumoxtran-10-enhanced MRI was 0·96 (SE 0·01), DOR 123·05 (95% CI 5·93–256·93). Unenhanced MRI had less overall sensitivity (0·63 [0·57–0·69]) and specificity (0·93 [0·91–0·94]), with an overall weighted area under the ROC curve of 0·84 (SE 0·11) and DOR of 26·75 (95% CI 8·48–84·42). Significant heterogeneity was noted for studies reporting enhanced MRI and unenhanced MRI. Metaregression analysis confirmed the significant effect of ferumoxtran-10 in the diagnostic precision of MRI (p=0·001).InterpretationFerumoxtran-10-enhanced MRI is sensitive and specific in detection of lymph-node metastases for various tumours. It offers higher diagnostic precision than does unenhanced MRI for detection of lymph-node metastases, and allows functional and anatomical definition when used as an imaging modality.