Liver metastases: optimization of MR imaging pulse sequences at 1.0 T

Twenty patients with known liver metastases were examined with magnetic resonance imaging; four different pulse sequences were used and six different images were produced to allow comparison of pulse sequence performance at a 1.0-T field strength. Pulse sequence performance was in each case calculated by measuring contrast-to-noise ratios (C/N) comparing normal liver, metastatic tumors to liver, and background noise. All pulse sequences required approximately the same length of time for data acquisition. Short inversion time inversion-recovery (STIR) sequences yielded the greatest signal difference-to-noise ratio in 17 patients. Phase contrast images produced the greatest contrast ratio in three patients. Although short TR, short TE spin-echo sequences provided the best anatomic detail, in no patient did this sequence yield the greatest signal difference-to-noise ratio in the comparison of liver and tumor. Differences in field strength and in equipment software and hardware may account for the discrepancy between our findings and previously published data.