Takao Iwasaki MD, Presenter: Nothing to Disclose

Emiko Mikami, Abstract Co-Author: Nothing to Disclose

Tooru Shimosegawa, Abstract Co-Author: Nothing to Disclose

Osamu Arai, Abstract Co-Author: Nothing to Disclose

Tsuyoshi Mitake, Abstract Co-Author: Nothing to Disclose

Ultrasound is simple, noninvasive and real-time, however, less objective than CT or MRI. To solve the problem without spoiling the advantages, utilizing virtual reality technology and multi-detector row CT, which acquires volume data and demonstrates any MPR (Multi-Planar Reconstruction) images, we developed prototype single phase real-time virtual sonography and introduced at RSNA 2003 (infoRAD 9424). Now we developed multi-phase real-time virtual sonography (MRVS). The purpose of the study is to introduce the MRVS system and evaluate its clinical value in diagnostic imaging of the liver

The MRVS system is composed by magnetic motion tracking device, image-processing workstation and ultrasound equipment. The magnetic sensor fastened to the ultrasound probe registers and transmits the spatial location and orientation of the probe to the workstation which possesses CT volume data (nonenhanced, arterial, portal venous, delayed phase). The workstation computes and displays the multi-phase (up to 4 phase) MPR image corresponding to the ultrasound image in 10 frame/sec. When starting RVS, the position adjustment is performed at the xiphoid process. Discrepancy by respiratory movement is rectified by adjust system.

MRVS was performed in 7 hepatocellular carcinoma patients. Two patients had the portal vein tumor thrombosis. Every patient underwent contrast-enhanced ultrasound. Each phase MPR image of target tumor was displayed under good position correspondence with ultrasound image in all the patients. The relationship between tumor and surrounding vessels was easily understood. MRVS facilitated the grasp of hemodynamics and 3-D architecture of portal vein tumor thrombosis, which is difficult by ultrasound or CT alone. The synergic effect which not only virtual MPR image helps understanding of ultrasound image but also ultrasound helps understanding of CT image affected.

MRVS acquired the objectivity without spoiling the advantages of ultrasound. The real-time existence of reference imaging, which must be the most convincing evidence imaging, enabled us to perform precise and definite imaging analysis. The MRVS system can be a novel evidence-based imaging modality.

T.M.,O.A.: Osamu Arai and Tsuyoshi Mitake are employees of Hitachi Medical Corporation.T.I.: Takao Iwasaki has received a grant from Hitachi Medical Corporation.

Iwasaki, T, Mikami, E, Shimosegawa, T, Arai, O, Mitake, T, Multi-phase Real-time Virtual Sonography: A Novel Evidence-based Imaging for Hepatocellular Carcinoma.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4416267.html