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

Will O, Purkayastha S, Chan C, Athanasiou T, Darzi AW, Gedroyc W, Tekkis PP

Centre for Academic Surgery, Barts and The London, Queen Mary's School of Medicine and Dentistry, Whitechapel, London, UK.

BACKGROUND: At 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. METHODS: We 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. FINDINGS: Summary 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). INTERPRETATION: Ferumoxtran-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.

Published 3 January 2006 in Lancet Oncol, 7(1): 52-60.
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