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  • Oral presentation
  • Open Access

A comparison of methods for determining the partition coefficient of gadolinium in the myocardium using T1 mapping

  • Rajesh Janardhanan1,
  • Ronny S Jiji1,
  • Jeremy Brooks1,
  • Frederick H Epstein1,
  • Christopher M Kramer1 and
  • Michael Salerno1
Journal of Cardiovascular Magnetic Resonance201113(Suppl 1):O81

https://doi.org/10.1186/1532-429X-13-S1-O81

Published: 2 February 2011

Keywords

Partition CoefficientLate Gadolinium EnhancementHeart BeatDiffuse Myocardial FibrosisMOLLI Sequence

Introduction

Late gadolinium enhancement can evaluate focal, but not diffuse myocardial fibrosis. T1-mapping techniques can quantify fibrosis by calculating the partition coefficient (λ) of gadolinium (Gd). One method (CI) calculates λ at equilibrium following a continuous infusion of Gd, while the other, early post-contrast method (EPC), determines λ from multiple post-contrast time points after Gd injection. The Modified Look-Locker Inversion Recovery (MOLLI) technique accurately performs T1 mapping, but may be limited in practice due to the long breathhold required. A shortened-MOLLI technique (Sh-MOLLI) has been described, which only allows a single heart beat for magnetization recovery.

Objectives

To (i) compare T1 values determined with reduced breathhold MOLLI schemes to the standard MOLLI technique, and (ii) to directly compare λ determined by the CI and EPC methods.

Methods

T1 mapping was performed in 10 healthy volunteers (age 34±11) on a Siemens 1.5T Avanto using 3 MOLLI schemes: (i) Standard MOLLI (ii) 3-5 MOLLI (11 heart beats, 2 inversions, 3 recovery beats, 8 images), (iii) 2-2-4 MOLLI (12 heart beats, 3 inversions, 2 recovery beats, 8 images). Sequence Parameters included: TE/TR/FA 1.1 ms/2.5ms/35°, FOV= 340 x 260, resolution 1.8mm x 1.8mm, thickness 8mm. T1 was determined pre-contrast and every 5 minutes following injection of 0.1mmol/kg Gd-DTPA. At 15 minutes a continuous infusion of 0.001 mmol/kg Gd was administered until equilibrium was achieved. λ was determined using the CI and EPC methods. T1 maps were calculated and manually segmented using an in-house MATLAB program.

Results

The standard MOLLI and the 3-5 MOLLI sequences provided comparable T1 values for myocardium and blood both pre- and post-contrast, whereas the 2-2-4 MOLLI sequence had a bias towards lower T1 values pre-contrast (see table 1). There was good agreement between the partition co-efficient of gadolinium for the CI method and for the EPC method (see Figure 1).
Table 1

Mean T1 values and partition co-efficients observed

Mean Values

Standard MOLLI

3-5 MOLLI

2-2-4 MOLLI

P-value

T1 of blood pre-contrast (msec)

1478±86

1480±100

1390±91

0.06

T1 of myocardium pre-contrast (msec)

972±27

953±38

919±84

0.11

T1 of blood post-contrast (msec)

488±36

487±43

484±44

0.97

T1 of myocardium post-contrast (msec)

601±37

597±37

600±30

0.96

Partition Co-efficients (CI-based method)

0.47±0.04

0.45±0.05

0.45±0.03

0.39

Partition Co-efficients (EPC-based method)

0.49±0.05

0.47±0.05

0.45±0.04

0.20

Figure 1

Figure 1

Conclusions

The 3-5 MOLLI sequence produces reliable T1 maps in a short clinically-applicable breathhold and is comparable to the standard approach. The 2-2-4 MOLLI sequence had a bias towards lower T1 values pre-contrast, possibly due to insufficient T1 relaxation between inversion pulses. The λ obtained by either the CI or EPC methods were similar. Using the EPC method, T1 mapping can quantify diffuse myocardial fibrosis without requiring a long equilibrium phase.

Authors’ Affiliations

(1)
University of Virginia, Charlottesville, USA

Copyright

© Janardhanan et al; licensee BioMed Central Ltd. 2011

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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