Volume quantification by contrast-enhanced ultrasound: an in-vitro comparison with true volumes and thermodilution

Abstract

BackgroundContrast-enhanced ultrasound (CEUS) has recently been proposed as a minimally- invasive, alternative method for blood volume measurement. This study aims at comparing the accuracy of CEUS and the classical thermodilution techniques for volume assessment in an in-vitro set-up.MethodsThe in-vitro set-up consisted of a variable network between an inflow and outflow tube and a roller pump. The inflow and outflow tubes were insonified with an ultrasound array transducer and a thermistor was placed in each tube. Indicator dilution curves were made by injecting indicator which consisted of an ultrasound-contrast-agent diluted in ice-cold saline. Both acoustic intensity- and thermo-dilution curves were used to calculate the indicator mean transit time between the inflow and outflow tube. The volumes were derived by multiplying the estimated mean transit time by the flow rate. We compared the volumes measured by CEUS with the true volumes of the variable network and those measured by thermodilution by Bland-Altman and intraclass-correlation analysis.ResultsThe measurements by CEUS and thermodilution showed a very strong correlation (rs = 0.94) with a modest volume underestimation by CEUS of −40 ± 28 mL and an overestimation of 84 ± 62 mL by thermodilution compared with the true volumes. Both CEUS and thermodilution showed a high statistically significant correlation with the true volume (rs = 0.97 (95% CI, 0.95 - 0.98; P<0.0001) and rs = 0.96 (95% CI, 0.94 - 0.98; P<0.0001, respectively).ConclusionsCEUS volume estimation provides a strong correlation with both the true volumes in-vitro and volume estimation by thermodilution. It may therefore represent an interesting alternative to the standard, invasive thermodilution technique.

Noninvasive pulmonary transit time: A new parameter for general cardiac performance

“…[10][11][12][13] Moreover, normalized left atrial transit times are correlated with invasive left ventricular pressure measurements. 14,15 CEUS-derived PTT correlates well with true volumes in an in-vitro setup, 16 with PTT measured via MRI and with levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP). 1 Choi et al 17 showed that cardiac output measured by right heart catheterization correlates with transit times measured with contrast echocardiography.…”

“…Moreover, normalized left atrial transit times are correlated with invasive left ventricular pressure measurements . CEUS‐derived PTT correlates well with true volumes in an in‐vitro setup, with PTT measured via MRI and with levels of N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) . Choi et al .…”

Oesophageal Doppler guided optimization of cardiac output does not increase visceral microvascular blood flow in healthy volunteers

“…CEUS has been validated for accurately measuring visceral blood flow against a number of proven technologies. Numerous in vitro and in vivo studies have validated the accuracy of CEUS in assessing microvascular blood flow, demonstrating close correlation with thermodilution (Herold et al, 2013), mechanically controlled flow (Wei et al, 1998) and end-organ microvascular perfusion (Rim et al, 2001;Wei et al, 2001).…”

“…ODM has been validated against PAFC thermodilution techniques in a 61 number of patient populations [7]. ODM has allowed a number of algorithms to be 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 [17], mechanically controlled flow [18] and end organ microvascular 87 perfusion [19], [20] . tracking changes in MBF of the intra-abdominal viscera [21,…”

The relationship between pulmonary artery wedge pressure and pulmonary blood volume derived from contrast echocardiography: A proof‐of‐concept study

“…Prior studies have compared echocardiographically-derived and invasively determined PBV in vitro (4) and in patients undergoing cardiac surgery (5). PBV is related to left atrial (LA) pressure (6).…”