fMRI predicts response to liver tumor treatment

Contrast enhancement and metabolic changes detected with functional MR imaging can help interventional radiologists anticipate the effects of transarterial chemoembolization on primary and metastatic tumors of the liver.

Clinical trials from Johns Hopkins University and Northwestern University come on the heels of a third study showing that contrast-enhanced and diffusion-weighted MRI can confirm the effects of transarterial chemoembolization (TACE) on liver metastases from neuroendocrine tumors. Results were presented March 17 at the 2008 Society of Interventional Radiology meeting.

Northwestern medical student Neel K. Naik and colleagues enrolled 21 patients with hepatocellular carcinoma who underwent TACE and pre- and postprocedural 1.5T gadolinium-enhanced T1-weighted MR and DWI with follow-up at one and three months. They found DWI changes a few weeks after treatment began that were useful for predicting TACE effects two months before they actually took place and became evident with anatomic MRI and other types of imaging.

Previous research has shown that functional MRI can characterize liver lesions, but no study to date had looked at the possibility of predicting response to TACE, Naik said.

In another study, interventional radiology fellow Dr. Josephina A. Vossen and colleagues at Johns Hopkins evaluated 19 patients with unresectable primary or metastatic liver tumors treated with TACE. Patients underwent unenhanced/contrast-enhanced MRI and MR spectroscopy before and after a single treatment. Two radiologists interpreted results by consensus.

They found 11 patients with successful tumor embolization showed loss of choline peak on MR spectroscopy, significant increase in apparent diffusion coefficient values (22%, p = 0.004), and significant decrease in tumor arterial and venous enhancement (43%, p = 0.005 and 40%, p = 0.002, respectively). Patients with no evidence of tumor response had a stable choline concentration, tumor enhancement, and ADC.

"These functional findings preceded tumor regression in size and may be utilized to detect early therapeutic response," Vossen said.