Spectrum of MRI Appearances of Untreated Metastases of the Liver

OBJECTIVE. The purpose of our study was to identify the spectrum of MRI appearances of untreated liver metastases from different primary origins.MATERIALS AND METHODS. Over a period of 52 months, we used our clinical information system to retrospectively identify the first MRIs obtained in 165 consecutive patients who had untreated liver metastases. All patients had histologic confirmation of the primary tumor. Liver metastases were confirmed at histologic examination, on imaging, or at clinical follow-up. MR sequences used included T1-weighted spoiled gradient-echo, T2-weighted half-Fourier acquisition single-shot turbo spin-echo, and serial gadolinium-enhanced spoiled gradient-echo imaging. Size, signal intensity characteristics, and pattern of enhancement of the metastases on MRIs were evaluated by two radiologists in consensus. Lesions were categorized by size: smaller than 1.5 cm, between 1.5 and 3.0 cm, and larger than 3.0 cm.RESULTS. A total of 516 metastases (size range, 5-120 mm; mean, 28 mm) wer...