On the utility of subharmonic microbubble signals to detect portal hypertension

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: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


In this work, the efficacy of subharmonic aided pressure estimation to detect portal hypertension (PH; i.e., portal vein (PV) pressures > 6-10 mmHg) is investigated. A Logiq 9 ultrasound scanner (GE Healthcare, Milwaukee, WI) with a 4C probe (transmit/receive: 2.5/1.25 MHz) was configured to obtain unprocessed radiofrequency (RF) data post pulse inversion. Fourteen canines were scanned. The main PV was accessed following a mid-line abdominal incision. Acute PH was induced using Gelfoam administration (8 canines; low-flow PH model) and using an arteriovenous fistula (6 canines; femoral artery to PV; high-flow PH model). A Millar pressure catheter introduced in the main PV indicated reference PV pressures. The RF data corresponding to 4 transmit cycles at 20 % and 40 % incident acoustic power (IAP) levels and pressure catheter data were acquired synchronously during infusion of Sonazoid (GE Healthcare, Oslo, Norway; 0.015 μl/kg/min) microbubbles, before and after inducing PH (5 s acquisitions; n = 3). The mean subharmonic amplitude from all acquired frames was extracted from the RF data corresponding to PV location. Linear regression analyses with leave-one-out cross validation technique were used to obtain PV pressures from the subharmonic amplitude (data from 3 canines was excluded due to extraneous conditions). The resulting PV pressures were compared to pressure catheter data. Overall, mean errors were-0.15 mmHg (p = 0.92) and-0.09 mmHg (p = 0.95) with 20 and 40 % IAP levels, respectively. For baseline PV pressures, mean errors were 3.50 mmHg (p = 0.11) and 3.64 mmHg (p = 0.10), while for PH pressures the mean errors were-3.80 mmHg (p = 0.07) and-3.83 mmHg (p = 0.06), with 20 and 40 % IAP levels, respectively. The sensitivity, specificity and accuracy of detecting moderate through severe PH (cut-off value: 16 mmHg PV pressure) in this cohort (n = 9) were 78 %, 69 % and 73 % for 20 % IAP and 78 %, 77 % and 77 % for 40 % IAP. Ambient pressure modulated subharmonic signals can be used for detecting PH in canines and thus, might be used to diagnose patients in the future.

Original languageEnglish
Title of host publication2012 IEEE International Ultrasonics Symposium, IUS 2012
Number of pages4
StatePublished - 2012
Event2012 IEEE International Ultrasonics Symposium, IUS 2012 - Dresden, Germany
Duration: 7 Oct 201210 Oct 2012

Publication series

NameIEEE International Ultrasonics Symposium, IUS
ISSN (Print)1948-5719
ISSN (Electronic)1948-5727


Conference2012 IEEE International Ultrasonics Symposium, IUS 2012


  • Subharmonic aided pressure estimation
  • noninvasive pressure estimation
  • portal hypertension
  • portal vein pressure
  • ultrasound contrast agents


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