Investigating the Efficacy of Subharmonic Aided Pressure Estimation for Portal Vein Pressures and Portal Hypertension Monitoring

Jaydev K. Dave, Valgerdur G. Halldorsdottir, John R. Eisenbrey, Daniel A. Merton, Ji Bin Liu, Jian Hua Zhou, Hsin Kai Wang, Suhyun Park, Scott Dianis, Carl L. Chalek, Feng Lin, Kai E. Thomenius, Daniel B. Brown, Flemming Forsberg

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


The efficacy of using subharmonic emissions from Sonazoid microbubbles (GE Healthcare, Oslo, Norway) to track portal vein pressures and pressure changes was investigated in 14 canines using either slow- or high-flow models of portal hypertension (PH). A modified Logiq 9 scanner (GE Healthcare, Milwaukee, WI, USA) operating in subharmonic mode (ftransmit: 2.5 MHz, freceive: 1.25 MHz) was used to collect radiofrequency data at 10-40% incident acoustic power levels with 2-4 transmit cycles (in triplicate) before and after inducing PH. A pressure catheter (Millar Instruments, Inc., Houston, TX, USA) provided reference portal vein pressures. At optimum insonification, subharmonic signal amplitude changes correlated with portal vein pressure changes; r ranged from -0.82 to -0.94 and from -0.70 to -0.73 for PH models considered separately or together, respectively. The subharmonic signal amplitudes correlated with absolute portal vein pressures (r: -0.71 to -0.79). Statistically significant differences between subharmonic amplitudes, before and after inducing PH, were noted (p ≤ 0.01). Portal vein pressures estimated using subharmonic aided pressure estimation did not reveal significant differences (p > 0.05) with respect to the pressures obtained using the Millar pressure catheter. Subharmonic-aided pressure estimation may be useful clinically for portal vein pressure monitoring.

Original languageEnglish
Pages (from-to)1784-1798
Number of pages15
JournalUltrasound in Medicine and Biology
Issue number10
StatePublished - Oct 2012

Bibliographical note

Funding Information:
This study was supported by National Institutes of Health grants R21 HL081892 and RC1 DK087365 (supporting JRE) and US Army Medical Research & Material Command grant W81XWH-08-1-0503 (supporting VGH). The authors acknowledge the support of GE Healthcare, Oslo, Norway, for supplying Sonazoid.


  • Noninvasive pressure estimation
  • Portal hypertension
  • Subharmonic imaging
  • Subharmonic-aided pressure estimation
  • Ultrasound contrast agents


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