MR Imaging Perfusion Mismatch: A Technique to Verify Successful Targeting of Liver Tumors during Transcatheter Arterial Chemoembolization

Purpose: To evaluate the combined use of transcatheter intraarterial perfusion (TRIP) magnetic resonance (MR) imaging and dynamic contrast-enhanced MR imaging to determine complete tumor targeting during transcatheter arterial chemoembolization (TACE) when performed within an integrated MR imaging-interventional radiology (IR) angiography suite. Materials and Methods: Between October 2006 and March 2007, eight consecutive patients with unresectable hepatocellular carcinoma (HCC) successfully underwent TACE in a combined MR imaging-IR suite. All patients were male, with a mean age of 59 years (range, 41-71 years). Tumor enhancement on TRIP MR images before and after TACE were qualitatively compared with dynamic contrast-enhanced MR images obtained after TACE. The authors computed the prevalence of perfusion mismatch. The presence of a perfusion mismatch was judged in a binary fashion. Results: A perfusion match, confirming complete tumor targeting, occurred in six of the eight patients (75%). There was a perfusion mismatch in two patients (25%). Subsequent interrogation showed that the underlying cause of the mismatch was secondary to an unexpected collateral vessel in the first patient and watershed location of the tumor in the second patient. Conclusions: Performing TACE in an MR imaging-IR suite can facilitate complete tumor targeting. By comparing perfusion images from TRIP and contrast-enhanced MR sequences, the operator gains confidence and can potentially obtain more selective catheter placement during TACE.