Diagnostic and Interventional Radiology
Abdominal Imaging - Original Article

Speed of sound index for liver steatosis estimation: a reliability study in normal subjects


Diagnostic Echotomography SA, Kifissia, Greece


Department of Medical Physics, University of Patras, School of Medicine, Rion, Greece


2nd Department of Medicine, National and Kapodistrian University of Athens, Medical School, Hippokration Hospital, Greece

Diagn Interv Radiol 2022; 28: 418-427
DOI: 10.5152/dir.2022.21019
Read: 400 Downloads: 113 Published: 03 September 2021

Non-alcoholic fatty liver disease (NAFLD) is the most widespread type of chronic liver disease in the Western countries. Ultrasound (US) is widely used for NAFLD staging. The Resona 7 US system (Mindray Bio-Medical Electronics Co., Ltd.) includes an image optimization and speed of ultrasound-related feature, Sound Speed Index (SSI). SSI is applied in a region of interest (ROI) that could potentially aid in tissue characterization. The purpose of this study is to evaluate the reliability of SSI on various examination parameters on normal subjects.

Twenty normal subjects were examined by two radiologists performing SSI measurements in the liver in different ROI depths and sizes. Intraclass correlation coefficient (ICC) was calculated to measure intra- and inter-observer variability and inter-ROI variability.

For all ROIs and both radiologists, the mean inter-observer ICC was 0.62 and the mean intraobserver ICC was 0.52 and 0.79. The mean SSI values for all ROIs and examiners were in the range 1528.79-1540.16 m/s.

The results indicate that SSI can lead to reliable measurements on normal subjects, independent of ROI size but dependent on ROI placement. More studies processing NAFLD patients, utilizing reference methods of liver fat quantification either for reliability or correlation with SSI, should be performed to further investigate the relevance of the SSI as a potential biomarker in clinical practice for liver steatosis grading.

You may cite this article as: Gatos I, Drazinos P, Loupas T, Yarmenitis S, Koskinas J, Zoumpoulis PS. Speed of sound index for liver steatosis estimation: A reliability study in normal subjects. Diagn Interv Radiol. 2022;28(5):418-427.

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