Development of a method for measuring spleen stiffness by transient elastography using a new device and ultrasound-fusion method.

• Main Authors: Takaaki Tanaka, Masashi Hirooka, Yohei Koizumi, Takao Watanabe, Osamu Yoshida, Yoshio Tokumoto, Yoshiko Nakamura, Koutarou Sunago, Atsushi Yukimoto, Masanori Abe, Yoichi Hiasa
• Format: Article
• Language: English
• Published: Public Library of Science (PLoS) 2021-01-01
• Series: PLoS ONE
• Online Access: https://doi.org/10.1371/journal.pone.0246315

<h4>Background</h4>Hepatic venous pressure gradient (HVPG) is the gold standard index for evaluating portal hypertension; however, measuring HVPG is invasive. Although transient elastography (TE) is the most common procedure for evaluating organ stiffness, accurate measurement of spleen stiffness (SS) is difficult. We developed a device to demonstrate the diagnostic precision of TE and suggest this technique as a valuable new method to measure SS.<h4>Methods</h4>Of 292 consecutive patients enrolled in this single-centre, translational, cross-sectional study from June through September in 2019, 200 underwent SS measurement (SSM) using an M probe (training set, n = 130; inspection set, n = 70). We performed TE with B-mode imaging using an ultrasound-fusion method, printed new devices with a three-dimensional printer, and attached the magnetic position sensor to the convex and M probes. We evaluated the diagnostic precision of TE to evaluate the risk of esophagogastric varices (EGVs).<h4>Results</h4>The median spleen volume was 245 mL (range, 64-1,720 mL), and it took 2 minutes to acquire a B-mode image using the ultrasound-fusion method. The median success rates of TE were 83.3% and 57.6% in patients with and without the new device, respectively (p<0.001); it was 76.9% and 35.0% in patients with and without splenomegaly (<100 mL), respectively (p<0.001). In the prediction of EGVs, the areas under the receiver operating characteristic curve were 0.921 and 0.858 in patients with and without the new device, respectively (p = 0.043). When the new device was attached, the positive and negative likelihood ratios were 3.44 and 0.11, respectively. The cut-off value of SSM was 46.0 kPa. Data that were similar between the validation and training sets were obtained.<h4>Conclusions</h4>The SS can be precisely measured using this new device with TE and ultrasound-fusion method. Similarly, we can estimate the bleeding risk due to EGV using this method.