Sabine Fanny Bensamoun, Presenter: Nothing to Disclose

Ludovic Robert, Abstract Co-Author: Nothing to Disclose

Fabrice Charleux MD, Abstract Co-Author: Nothing to Disclose

The purpose of this study is to establish the proper imaging protocol to determine kidney stiffness using MRE and to simultaneously measure other tissues stiffnesses such as liver, spleen and psoas.

Eleven volunteers without kidney abnormalities underwent a MRE test. The subjects lay supine in a 1.5T MRI and a cylindrical acoustic driver was positioned in contact with the rib cage to induce shear waves at 60Hz. A coronal oblique plan going through the renal parenchyma and the liver tissue was prescribed. Acquisitions were done during apnea, with a Gradient Echo sequence, matrix: 256x64, 2 offsets and TR/TE: 100 ms/min full. A map of stiffness was generated from the wave displacement providing a spatial distribution of the kidney’s stiffness as well as liver, spleen and psoas muscle.

A higher shear modulus was found for the kidney (4.32 ± 0.59 kPa) and the spleen (4.75 ± 0.70 kPa) compared to the liver (2.27 ± 0.19 kPa) and the psoas (2.60 ± 0.25 kPa) muscle. The cartography of kidney’s stiffness revealed the different structures (renal sinus, medulla and cortex) located within the kidney. The renal sinus revealed a higher significant stiffness (6.78 ± 0.10 kPa) than the medulla (5.46 ± 0.48 kPa) and the cortex (4.35 ± 0.32 kPa).

The present study is the first to show the strong sensibility of the MRE technique to represent the spatial distribution of stiffness correlated with the structural composition of the kidney. Though the use of an axial plan, it is not possible to establish a correlation between the structural and functional properties of the kidney. This information is of great importance for the characterization of kidney abnormalities present in the renal sinus, medulla or within the cortex. The spleen and kidney exhibits higher stiffness than the liver due to their physiological structure. Moreover, the stiffness of the psoas is similar to other skeletal muscle with the same muscle fiber orientation.

This study demonstrates that MRE technique could be a potential clinical tool for the characterization of renal damage in order to detect malignant and mild tumors.

Bensamoun, S, Robert, L, Charleux, F, Development of a New Protocol to Simultaneously Measured the Stiffness of Kidney, Liver, Spleen and Psoas Muscle with Magnetic Resonance Elastography (MRE).  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9012126.html