September 26, 2013

Noninvasive Imaging Test Detects Liver Disease in Children

Medscape Medical News

Laurie Barclay, MD

Sep 25, 2013

Magnetic resonance elastography (MRE) is a new, noninvasive imaging test that accurately detects fibrosis in children, including those who are severely obese, with nonalcoholic fatty liver disease (NAFLD) and other forms of chronic liver disease, according to a case series. The findings of the case series were published online September 23 in the Journal of Pediatrics.

"Because many pediatrics patients in the United States with NAFLD are severely obese, MRE is likely to be superior to ultrasound-based elastography in this population, as ultrasound-based methods are less reliable in severely obese patients," lead author Stavra Xanthakos, MD, a gastroenterologist at Cincinnati Children's Hospital Medical Center in Ohio, said in a news release.

The increasing prevalence of obesity in the pediatric population has also driven the increasing prevalence of NAFLD, which is now estimated to affect 13% of adolescents, according to the release. Complications of NAFLD include progressive liver disease and liver failure.

In 2011 and 2012, 35 patients aged 4 to 20 years (median, 13 years) with chronic liver disease underwent MRE and liver biopsy. Median body mass index percentile was 99.2.

Compared with liver biopsy as a gold standard, MRE was highly accurate in detecting fibrosis of stage 2 or greater, even in severely obese patients. Using a cutoff of 2.71 kPa, sensitivity for detecting significant fibrosis was 88% and specificity was 85%, with an area-under-the–receiver operating characteristic curve of 0.92 (95% confidence interval, 0.79 - 1.00; P = .02).

MRE Promising, but "Not Yet Ready for Primetime"

MRE, which uses magnetic resonance and low-frequency sound waves to measure tissue stiffness, can be performed in several minutes. At Cincinnati Children's Hospital Medical Center, more than 200 children have undergone liver MRE, with no reported adverse events. In this case series, only 1 patient, aged 4 years, required sedation.

If the findings are confirmed in larger series, use of MRE could reduce the need for liver biopsies to diagnose fibrosis. The latter technique is expensive, invasive, associated with risks, and may be frightening for children and adolescents. Furthermore, biopsy results may be misclassified because of sampling error, insufficient tissue sample size, or fragmentation.

"Having the ability to easily and noninvasively assess the degree of fibrosis in a child's liver could help us identify the issue early and bring the right course of treatment in a timely and effective manner," coauthor Daniel Podberesky, MD, chief of thoracoabdominal imaging at the medical center said in the news release. "An added strength of magnetic resonance technology is the ability to more precisely measure liver fat, which allows us to non-invasively determine changes in liver fat quantity after clinical interventions."

Limitations of this study include its small sample size and case series design.

"Our results show the exciting potential of MRE to improve clinical care and reduce dependence on liver biopsies, but it is not yet ready for primetime clinical use," Dr. Xanthakos concludes in the news release. "In addition to validation in larger pediatric cohorts, we still need to determine whether MRE can predict changes in liver disease over time. We hope to study MRE in patients to test how well changes in imaging correlate with changes in liver stiffness after treatment or lifestyle changes."

The National Institutes of Health, the National Center for Research Resources, and the National Center for Advancing Translational Sciences supported this study. Dr. Podberesky received travel reimbursement from GE Healthcare. The other authors have disclosed no relevant financial relationships.

J Pediatr. Published online September 23, 2013. Full text

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