Published Online May 26, 2016

Ultrasound is an effective tool for measuring liver stiffness, one of the key indicators of disease. It has additional value as a less-invasive alternative to biopsy. But it comes with a catch.

The weight of the children matters significantly. Ultrasound was less effective for patients with a body-mass index (BMI) exceeding 30 kg/m2, according to an analysis of ultrasonographic point shear-wave elastography. This ultrasound method has been increasingly used to quantify liver fibrosis.

The study, published online in Radiology, included first-author Andrew Trout, MD, Department of Radiology, and Cincinnati Children’s colleagues in Radiology and the Division of Gastroenterology, Hepatology and Nutrition.

Researchers evaluated 55 patients with a mean age of 14 years. They looked at the correlation between ultrasound and magnetic resonance (MR) elastography liver shear-wave speed measurements.

Elastography maps a target organ to show how stiff the tissue is. MR elastography is considered the reference standard in the absence of biopsy.

The goal was to see how well ultrasound data matched the MR data. Both methods were effective for the less heavy patients, but in the heavier group, the ultrasound data broke down.

“We believe this relates to technical (hardware and software) limitations and we are working with the equipment manufacturers to address these issues,” Trout says.

Despite its limitations in patients with higher BMI, ultrasound has become another effective way to evaluate the liver without the risk of biopsy.

“Ultrasound,” Trout adds, “has advantages over MRI in terms of cost, portability and ease of application that make this an attractive technique for measuring liver stiffness in children.”