Myocardial extravascular extracellular volume fraction measurement by gadolinium cardiovascular magnetic resonance in humans: slow infusion versus bolusReport as inadecuate




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Journal of Cardiovascular Magnetic Resonance

, 13:16

First Online: 04 March 2011Received: 30 November 2010Accepted: 04 March 2011

Abstract

BackgroundMyocardial extravascular extracellular volume fraction Ve measures quantify diffuse fibrosis not readily detectable by conventional late gadolinium Gd enhancement LGE. Ve measurement requires steady state equilibrium between plasma and interstitial Gd contrast. While a constant infusion produces steady state, it is unclear whether a simple bolus can do the same. Given the relatively slow clearance of Gd, we hypothesized that a bolus technique accurately measures Ve, thus facilitating integration of myocardial fibrosis quantification into cardiovascular magnetic resonance CMR workflow routines. Assuming equivalence between techniques, we further hypothesized that Ve measures would be reproducible across scans.

MethodsIn 10 volunteers ages 20-81, median 33 yr, 3 females, we compared serial Ve measures from a single short axis slice from two scans: first, during a constant infusion, and second, 12-50 min after a bolus 0.2 mmol-kg gadoteridol on another day. Steady state during infusion was defined when serial blood and myocardial T1 data varied <5%. We measured T1 on a 1.5 T Siemens scanner using a single-shot modified Look Locker inversion recovery sequence MOLLI with balanced SSFP. To shorten breath hold times, T1 values were measured with a shorter sampling scheme that was validated with spin echo relaxometry TR = 15 sec in CuSO4-Agar phantoms. Serial infusion vs. bolus Ve measures n = 205 from the 10 subjects were compared with generalized estimating equations GEE with exchangeable correlation matrices. LGE images were also acquired 12-30 minutes after the bolus.

ResultsNo subject exhibited LGE near the short axis slices where Ve was measured. The Ve range was 19.3-29.2% and 18.4-29.1% by constant infusion and bolus, respectively. In GEE models, serial Ve measures by constant infusion and bolus did not differ significantly difference = 0.1%, p = 0.38. For both techniques, Ve was strongly related to age p < 0.01 for both in GEE models, even after adjusting for heart rate. Both techniques identically sorted older individuals with higher mean Ve values.

ConclusionMyocardial Ve can be measured reliably and accurately 12-50 minutes after a simple bolus. Ve measures are also reproducible across CMR scans. Ve estimation can be integrated into CMR workflow easily, which may simplify research applications involving the quantification of myocardial fibrosis.

Electronic supplementary materialThe online version of this article doi:10.1186-1532-429X-13-16 contains supplementary material, which is available to authorized users.

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Author: Erik B Schelbert - Stephen M Testa - Christopher G Meier - William J Ceyrolles - Joshua E Levenson - Alexander J Blair

Source: https://link.springer.com/article/10.1186/1532-429X-13-16







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