Functional MRI may predict response of hepatocellular carcinoma to chemoembolization

Early knowledge of hepatocellular carcinoma (HCC) response to transcatheter arterial chemoembolization (TACE) is crucial for determining treatment success, timing of repeat treatment, and patient prognosis. Currently, magnetic resonance imaging (MRI) is used 1-3 mo after treatment to evaluate anatomical tumor response, based upon changes in tumor size and contrast-agent enhancement. Alternatively, diffusion-weighted imaging (DWI) can be used as a functional imaging technique to depict thermally induced motion of water molecules. The extent of water mobility within biological tissues can be quantified by a parameter called the apparent diffusion coefficient (ADC). Recently, ADC values have been shown to change within days to weeks after therapy, which is earlier than changes seen by conventional HCC anatomical size assessment. However, no studies to date have reported the intra-procedural characteristics of ADC and whether these values can predict future tumor response at the time of chemoembolization.

A research article to be published on July 7, 2010 in the World Journal of Gastroenterology addresses this question. The research team led by Professor Reed A Omary, from Department of Radiology, Northwestern University, Chicago, used functional magnetic resonance imaging (MRI) to measure changes in tumor activity at the time of treatment, and compared them to tumor structural changes on conventional MRI at standard 1- and 3-mo follow-up periods.

Their results suggest that patients whose intra-procedural ADC values increase or decrease by > 15% are more likely to have a favorable anatomical tumor response 1 mo later.

This result is encouraging because early knowledge of HCC response after initial therapy is essential to revise prognosis and guide future therapy. Use of DWI and ADC mapping in conjunction with traditional anatomical imaging evaluation could further improve tumor response interpretation and subsequent treatment planning. At present, MR/Interventional radiology suites permit the acquisition of immediate quantitative functional imaging changes, in both tumor perfusion and now diffusion. Which of these two functional parameters is more effective as an intra-procedural biomarker to tailor HCC therapy awaits verification by future studies.

Reference: Chung JC, Naik NK, Lewandowski RJ, Deng J, Mulcahy MF, Kulik LM, Sato KT, Ryu RK, Salem R, Larson AC, Omary RA. Diffusion-weighted magnetic resonance imaging to predict response of hepatocellular carcinoma to chemoembolization. World J Gastroenterol 2010; 16(25): 3161-3167

http://www.wjgnet.com/1007-9327/full/v16/i25/3161.htm

Correspondence to: Reed A Omary, MD, MS, Professor of Radiology and Biomedical Engineering, Vice Chair of Research, Department of Radiology, Section of Interventional Radiology, Northwestern University Feinberg School of Medicine, 737 N. Michigan Ave., Suite 1600, Chicago, IL 60611, United States. reed@northwestern.edu

Telephone: +1-312-6953774 Fax: +1-312-9265991

World Journal of Gastroenterology (WJG), a leading international journal in gastroenterology and hepatology, has established a reputation for publishing first class research on esophageal cancer, gastric cancer, liver cancer, viral hepatitis, colorectal cancer, and H. pylori infection and provides a forum for both clinicians and scientists. WJG has been indexed and abstracted in Current Contents/Clinical Medicine, Science Citation Index Expanded (also known as SciSearch) and Journal Citation Reports/Science Edition, Index Medicus, MEDLINE and PubMed, Chemical Abstracts, EMBASE/Excerpta Medica, Abstracts Journals, Nature Clinical Practice Gastroenterology and Hepatology, CAB Abstracts and Global Health. ISI JCR 2009 IF: 2.092. WJG is a weekly journal published by WJG Press. The publication dates are the 7th, 14th, 21st, and 28th day of every month. WJG is supported by The National Natural Science Foundation of China, No. 30224801 and No. 30424812, and was founded with the name of China National Journal of New Gastroenterology on October 1, 1995, and renamed WJG on January 25, 1998.