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

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

doi:10.1016/j.ultrasmedbio.2012.06.013

Cited by 38 publications

(48 citation statements)

References 55 publications

(115 reference statements)

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“…Since its implementation on two modified commercial US scanners, SHAPE has been used to track dynamic pressures in vitro (12), to monitor interstitial fluid pressures in a swine melanoma model (13), and to separately measure left ventricular pressures and changes in portal pressures in canine models (14,15).…”

Section: Methodsmentioning

confidence: 99%

Chronic Liver Disease: Noninvasive Subharmonic Aided Pressure Estimation of Hepatic Venous Pressure Gradient

Eisenbrey

Dave²,

Halldorsdottir³

et al. 2013

Radiology

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Purpose:To compare subharmonic aided pressure estimation (SHAPE) with pressure catheter-based measurements in human patients with chronic liver disease undergoing transjugular liver biopsy. Materials and Methods:This HIPAA-compliant study had U.S. Food and Drug Administration and institutional review board approval, and written informed consent was obtained from all participants. Forty-five patients completed this study between December 2010 and December 2011. A clinical ultrasonography (US) scanner was modified to obtain SHAPE data. After transjugular liver biopsy with pressure measurements as part of the standard of care, 45 patients received an infusion of a microbubble US contrast agent and saline. During infusion, SHAPE data were collected from a portal and hepatic vein and were compared with invasive measurements. Correlations between data sets were determined by using the Pearson correlation coefficient, and statistical significance between groups was determined by using the Student t test. Results:-The 45 study patients included 27 men and 18 women (age range, 19-71 years; average age, 55.8 years). The SHAPE gradient between the portal and hepatic veins was in good overall agreement with the hepatic venous pressure gradient (HVPG) (R = 0.82). Patients at increased risk for variceal hemorrhage (HVPG > 12 mm Hg) had a significantly higher mean subharmonic gradient than patients with lower HVPGs (1.93 dB 6 0.61 [standard deviation] vs 21.47 dB 6 0.29, P , .001), with a sensitivity of 100% and a specificity of 81%, indicating that SHAPE may be a useful tool for the diagnosis of clinically important portal hypertension. Conclusion:Preliminary results show SHAPE to be an accurate noninvasive technique for estimating portal hypertension.q RSNA, 2013 Supplemental material: http://radiology.rsna.org/lookup /suppl

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Section: Methodsmentioning

confidence: 99%

Chronic Liver Disease: Noninvasive Subharmonic Aided Pressure Estimation of Hepatic Venous Pressure Gradient

Eisenbrey

Dave²,

Halldorsdottir³

et al. 2013

Radiology

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“…A secondary goal of this study was to compare SHAPE’s performance with 4, 8 and 16 transmit cycles. The clinical relevance and in vivo applications of SHAPE have been documented [1-4]. The current study builds on previous in vitro and in vivo SHAPE studies [1-7] and solves the problem of determining optimum IAO levels to insonate the ultrasound contrast agents (UCAs) for SHAPE applications.…”

Section: Introductionmentioning

confidence: 99%

“…The current study builds on previous in vitro and in vivo SHAPE studies [1-7] and solves the problem of determining optimum IAO levels to insonate the ultrasound contrast agents (UCAs) for SHAPE applications. If successful, this approach may help eliminate the problems of acquiring and analyzing the data offline at all IAO levels as was done previously [1-3, 6] and, thus, pave the way for real-time clinical pressure monitoring applications.…”

Section: Introductionmentioning

confidence: 99%

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On the implementation of an automated acoustic output optimization algorithm for subharmonic aided pressure estimation

et al. 2013

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Incident acoustic output (IAO) dependent subharmonic signal amplitudes from ultrasound contrast agents can be categorized into occurrence, growth or saturation stages. Subharmonic aided pressure estimation (SHAPE) is a technique that utilizes growth stage subharmonic signal amplitudes for hydrostatic pressure estimation. In this study, we developed an automated IAO optimization algorithm to identify the IAO level eliciting growth stage subharmonic signals and also studied the effect of pulse length on SHAPE. This approach may help eliminate the problems of acquiring and analyzing the data offline at all IAO levels as was done in previous studies and thus, pave the way for real-time clinical pressure monitoring applications. The IAO optimization algorithm was implemented on a Logiq 9 (GE Healthcare, Milwaukee, WI) scanner interfaced with a computer. The optimization algorithm stepped the ultrasound scanner from 0 to 100 % IAO. A logistic equation fitting function was applied with the criterion of minimum least squared error between the fitted subharmonic amplitudes and the measured subharmonic amplitudes as a function of the IAO levels and the optimum IAO level was chosen corresponding to the inflection point calculated from the fitted data. The efficacy of the optimum IAO level was investigated for in vivo SHAPE to monitor portal vein (PV) pressures in 5 canines and was compared with the performance of IAO levels, below and above the optimum IAO level, for 4, 8 and 16 transmit cycles. The canines received a continuous infusion of Sonazoid microbubbles (1.5 μl/kg/min; GE Healthcare, Oslo, Norway). PV pressures were obtained using a surgically introduced pressure catheter (Millar Instruments, Inc., Houston, TX) and were recorded before and after increasing PV pressures. The experiments showed that optimum IAO levels for SHAPE in the canines ranged from 6 to 40 %. The best correlation between changes in PV pressures and in subharmonic amplitudes (r = -0.76; p = 0.24), and between the absolute PV pressures and the subharmonic amplitudes (r = -0.89; p < 0.01) were obtained for the optimized IAO and 4 transmit cycles. Only for the optimized IAO and 4 transmit cycles did the subharmonic amplitudes differ significantly (p < 0.01) before and after increasing PV pressures. A new algorithm to identify optimum IAO levels for SHAPE has been developed and validated with the best results being obtained for 4 transmit cycles. The work presented in this study may pave the way for real-time clinical applications of estimating pressures using the subharmonic signals from ultrasound contrast agents.

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“…An early study in canines reported the possibility of a subharmonic aided pressure estimation (SHAPE) in the estimation of portal pressure 33. The same group examined the clinical effect of the technique in human subjects and found a good overall agreement (r=0.82) between the SHAPE gradient (the portal and hepatic veins) and HVPG 34.…”

Section: Contrast-enhanced Usmentioning

confidence: 99%

Ultrasonography for Noninvasive Assessment of Portal Hypertension

Maruyama

Yokosuka

2017

Gut and Liver

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Portal hypertension is a major pathophysiology in patients with cirrhosis. Portal pressure is the gold standard to evaluate the severity of portal hypertension, and radiological intervention is the only procedure for pressure measurement. Ultrasound (US) is a simple and noninvasive imaging modality available worldwide. B-mode imaging allows broad applications for patients to detect and characterize chronic liver diseases and focal hepatic lesions. The Doppler technique offers real-time observation of blood flow with qualitative and quantitative assessments, and the application of microbubble-based contrast agents has improved the detectability of peripheral blood flow. In addition, elastography for the liver and spleen covers a wider field beyond the original purpose of fibrosis assessment. These developments enhance the practical use of US in the evaluation of portal hemodynamic abnormalities. This article reviews the recent progress of US in the assessment of portal hypertension.

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

Cited by 38 publications

References 55 publications

Chronic Liver Disease: Noninvasive Subharmonic Aided Pressure Estimation of Hepatic Venous Pressure Gradient

Chronic Liver Disease: Noninvasive Subharmonic Aided Pressure Estimation of Hepatic Venous Pressure Gradient

On the implementation of an automated acoustic output optimization algorithm for subharmonic aided pressure estimation

Ultrasonography for Noninvasive Assessment of Portal Hypertension

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