Flemming Forsberg PhD, Presenter: Equipment support, Toshiba Corporation Equipment support, Siemens AG Research collaboration, General Electric Company Research collaboration, Ultrasonix Medical Corporation Research collaboration, Toshiba Corporation Advisory Board, Siemens AG Advisory Board, Toshiba Corporation

John Robery Eisenbrey PhD, Abstract Co-Author: Nothing to Disclose

Jaydev Dave, Abstract Co-Author: Nothing to Disclose

Valgerdur Halldorsdottir MSC, Abstract Co-Author: Nothing to Disclose

Jose M Gonzalez MD, Abstract Co-Author: Nothing to Disclose

Cynthia L Miller RN, Abstract Co-Author: Nothing to Disclose

Daniel Arthur Merton, Abstract Co-Author: Nothing to Disclose

Priscilla L.R.C. Machado MD, Abstract Co-Author: Nothing to Disclose

Suhyun Park PhD, Abstract Co-Author: Employee, General Electric Company

Scott Dianis MSc, Abstract Co-Author: Employee, General Electric Company

Carl Chalek PhD, Abstract Co-Author: Employee, General Electric Company

Kai E. Thomenius PhD, Abstract Co-Author: Employee, General Electric Company

Daniel B. Brown MD, Abstract Co-Author: Consultant, Cook Group Incorporated Consultant, Nordion, Inc Research support, St Jude Medical, Inc

Victor Navarro, Abstract Co-Author: Nothing to Disclose

Hepatic vein pressure gradient (HVPG) data is clinically useful in the management of cirrhosis and other liver diseases. Unfortunately, current HPVG measurements are either invasive catheter based measurements, or noninvasive but indirect and qualitative imaging approaches. Our group has previously shown the subharmonic amplitude of microbubble-based ultrasound contrast agents to be a good indicator of hydrostatic pressure (a technique known as SHAPE). Here, we present preliminary results from a first in humans, SHAPE study for the measurement of portal hypertension.

Following transjugular liver biopsy, 16 patients received a co-infusion of Sonazoid (0.72 μL microbubbles/kg/hour; GE Healthcare, Oslo, Norway) and saline (120 ml/hour). Subjects were scanned with a modified Logiq 9 scanner (GE Healthcare, Milwaukee, WI) with a 4C curvilinear probe. The acoustic output for optimal SHAPE sensitivity (the point of maximal change in subharmonic amplitude as a function of insonation pressure) was determined and used for pressure estimation. Radiofrequency data from the portal and hepatic veins were collected for 5 s in triplicate. Subharmonic amplitudes were extracted off-line and compared to catheter HVPG measurements (obtained as standard of care during biopsy) and model for end stage liver disease scores (MELD).

Normalized subharmonic signals from within the portal vein varied from 2.9 to 9.7 dB/cm/MPa, but showed a poor overall correlation with HVPG values (R = 0.49) and MELD scores (R = 0.24). Subharmonic amplitude variation between the hepatic and portal veins varied from -2.1 to 3.9 dB and showed a good overall fit to HVPG data (R = 0.72). The hepatic-portal SHAPE results showed a poor fit to MELD scores (R = 0.49), but only slightly worse than the fit of MELD data to actual HVPG (R = 0.66).

Preliminary results show a good correlation between SHAPE pressure estimates in the hepatic and portal veins and the catheter based reference standard (R = 0.72)

Subharmonic-aided pressure estimation with ultrasound contrast agents may eventually replace invasive pressure catheter measurements in the diagnosis and management of liver disease.

Forsberg, F, Eisenbrey, J, Dave, J, Halldorsdottir, V, Gonzalez, J, Miller, C, Merton, D, Machado, P, Park, S, Dianis, S, Chalek, C, Thomenius, K, Brown, D, Navarro, V, Noninvasive Subharmonic-aided Pressure Estimation in Patients with Suspected Portal Hypertension: Preliminary Results.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034432.html