Distinguishing hepatic metastases from hemangiomas: qualitative and quantitative diagnostic performance through dual echo respiratory-triggered fast spin echo magnetic resonance imaging.

OBJECTIVE: To determine the relative value of qualitative (reader opinion) and quantitative (values derived from dual echo T2 fast spin echo [FSE]) measures in distinguishing hepatic metastases from hemangiomas.
METHODS: Forty-nine patients with hemangiomas and 23 with metastases were studied with dual echo respiratory-triggered FSE and dynamic 2-dimensional spoiled gradient echo (GRE) imaging. Lesion T2 was estimated from signal intensity ratios on the first and second echoes. Two experienced radiologists independently evaluated groups of images based on 5 separate qualitative measures: first echo FSE, second echo FSE, first and second echo FSE, dynamic GRE, and all images together.
RESULTS: The mean calculated T2s were 226 +/- 74 milliseconds for hemangiomas and 105 +/- 22 milliseconds for metastases (P < 0.001). A T2 cutoff of 130 milliseconds distinguished metastases from hemangiomas with a sensitivity of 94%, specificity of 91%, and accuracy of nearly 94%. There was no significant difference between the best quantitative measure and the best qualitative measure for either reader.
CONCLUSION: Liver lesion T2 relaxation times calculated from dual echo FSE images provide information useful in discriminating metastases from hemangiomas, as does reader opinion.