Comparison of dual-phase helical CT with native and ferumoxide-enhanced magnetic resonance imaging in detection and characterization of focal liver lesions

Purpose: Evaluation of the diagnostic efficacy of contrast-enhanced, dual-p hase spiral CT and MRI before and after administration of SPIO particles in focal hepatic disease with previously uncertain diagnosis. Material and methods: In 46 patients in whom primary or secondary hepatic m alignancy was suspected, dual-phase spiral CECT and breath-held T1 -weighte d gradient-echo and T2-weighted fast spin-echo MRI (1.5 T, body-phased-arra y coil) before and after SPIO administration were compared. The indications for the subsequent MR[ studies were based on ambiguous findings on CECT. T he number of hepatic lesions, the overall lesion detection and characteriza tion was evaluated by consensus and compared to the gold standard (histolog ical proof in 30/46 of the cases, long-term follow-up in 16/46 of the cases ). Results: In 34 of 46 cases the correct diagnoses were established by CECT ( sensitivity 96%, specificity 48%) revealing significantly less lesions than MRI. Unenhanced MRI had sensitivity of 93% and specificity of 71%, whereas SPIO-enhanced MRI had sensitivity of 97% and specificity of 88%. The diffe rences between the modalities were even more pronounced in the detection of lesions smaller than 10 mm with SPIO-MRI as the most sensitive method. Conclusions: In this problem-oriented scenario, SPIO-enhanced MRI was super ior to spiral CT and unenhanced MRI regarding the diagnostic efficacy in th e pre-operative work-up of focal liver lesions. SPIO-enhanced MRI can be re commended as a problem solving tool for the clinical routine.