MAGNETIZATION-TRANSFER CONTRAST IMAGING OF HEPATIC NEOPLASMS

A method of performing magnetization transfer contrast (MTC) using a p ulse sequence based on a series of on-resonance binomial pulses preced ing a conventional spin-echo sequence has been recently described. We investigated this technique in the evaluation of circumscribed hepatic neoplasms on a 0.5 T imager. Conventional spin-echo imaging was perfo rmed in 18 patients with hepatic neoplasms, 15 with primary or metasta tic hepatic neoplasms, and 3 with cavernous hemangiomas. The T-1-weigh ted sequence was repeated following MTC saturation in 7 patients and t he proton density sequence was repeated following MTC saturation in 13 patients (both were used in two patients). The mean lesion-to-liver c ontrast for neoplasms worsened with T-1-MTC (0.87 vs. 1.04), but impro ved slightly with proton density-MTC (1.10 vs. 1.22) when compared to the corresponding non-MTC spin-echo images. However, these differences were not statistically significant (p =.19 and p =.16, respectively). The limited data on cavernous hemangiomas does not suggest these have consistently different MTC imaging characteristics from other hepatic neoplasms. In conclusion, MTC imaging using a binomial saturation pul se did not offer significant improvement in contrast between hepatic n eoplasms and normal liver. Refinements of the binomial pulse sequence will be necessary if a consistent improvement in lesion sensitivity is to be achieved. Evaluation of its role in increasing diagnostic speci ficity will require further investigation.