Optimization of dual-saturation single bolus acquisition for quantitative cardiac perfusion and myocardial blood flow maps

Abstract

BackgroundIn-vivo quantification of cardiac perfusion is of great research and clinical value. The dual-bolus strategy is universally used in clinical protocols but has known limitations. The dual-saturation acquisition strategy has been proposed as a more accurate alternative, but has not been validated across the wide range of perfusion rates encountered clinically. Dual-saturation acquisition also lacks a clinically-applicable procedure for optimizing parameter selection. Here we present a comprehensive validation study of dual-saturation strategy in vitro and in vivo.MethodsThe impact of saturation time and profile ordering in acquisitions was systematically analyzed in a phantom consisting of 15 tubes containing different concentrations of contrast agent. In-vivo experiments in healthy pigs were conducted to evaluate the effect of R2* on the definition of the arterial input function (AIF) and to evaluate the relationship between R2* and R1 variations during first-pass of the contrast agent. Quantification by dual-saturation perfusion was compared with the reference-standard dual-bolus strategy in 11 pigs with different grades of myocardial perfusion.ResultsAdequate flow estimation by the dual-saturation strategy is achieved with myocardial tissue saturation times around 100 ms (always <30 ms of AIF), with the lowest echo time, and following a signal model for contrast conversion that takes into account the residual R2* effect and profile ordering. There was a good correlation and agreement between myocardial perfusion quantitation by dual-saturation and dual-bolus techniques (R2 = 0.92, mean difference of 0.1 ml/min/g; myocardial perfusion ranges between 0.18 and 3.93 ml/min/g).ConclusionsThe dual-saturation acquisition strategy produces accurate estimates of absolute myocardial perfusion in vivo. The procedure presented here can be applied with minimal interference in standard clinical procedures.

Myocardial perfusion cardiovascular magnetic resonance: optimized dual sequence and reconstruction for quantification

“…A short readout (64 point) with wide bandwidth (3900 Hz/pixel) and short duration RF pulses (250 μs, time-bandwidth product = 2.0) were used to achieve low T2* losses (TE 1  = 0.76 ms). T2* dephasing loss has been a known concern in estimating AIF and conversion to [Gd] and approaches to this problem have focused either on minimizing the loss by choosing adequately short echo time (TE) [10] or on correcting for T2* loss based on modeling the relationship between T1 and T2* [11, 12]. In this work, the dual sequence approach was modified to incorporate a 2 echo acquisition for measurement of T2* during the bolus passage.…”

Quantitative 3D myocardial perfusion with an efficient arterial input function

“…The 3D acquisition requires a longer SRT compared with the AIF . While the longer SRT times are more optimal for 3D, they lead to an underestimation of high contrast agent concentrations (see the vial experiments in Figure ).…”

Transplantation of Allogeneic Pericytes Improves Myocardial Vascularization and Reduces Interstitial Fibrosis in a Swine Model of Reperfused Acute Myocardial Infarction

“…The protocol included (1) a standard segmented cine steady‐state free‐precession sequence to provide high‐quality anatomical references and to determine left ventricular end‐diastolic wall thickness (EDWT), left ventricular end‐diastolic volume (LVEDV), left ventricular end‐systolic volume (LVESV), and left ventricular ejection fraction (LVEF); (2) a late gadolinium‐enhanced sequence to assess infarct size; and (3) a dynamic acquisition with dual‐saturation technique during gadolinium‐based contrast administration to determine absolute myocardial perfusion 23, 24. CMR images were processed with a commercial analysis software (QMass MR 7.5 Medis, Leiden, the Netherlands and MR Extended Work Space 2.6, Philips Healthcare) and were analyzed by 2 independent blinded experienced investigators as previously described 23, 24, 25…”

“…23,24 CMR images were processed with a commercial analysis software (QMass MR 7.5 Medis, Leiden, the Netherlands and MR Extended Work Space 2.6, Philips Healthcare) and were analyzed by 2 independent blinded experienced investigators as previously described. [23][24][25]…”