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Improved accuracy of myocardial blood flow quantification by first pass perfusion MR when corrected for steady state T1 relaxation
© Zarinabad et al; licensee BioMed Central Ltd. 2013
- Published: 30 January 2013
- Myocardial Blood Flow
- Steady State Measurement
- Dynamic Contrast Enhance
- Pass Perfusion
- Myocardial Blood Volume
T1 weighted images were acquired before and after contrast injection to perform steady state measurements of myocardial blood volume (MBVss) (2): MBVSS = (1/T1post contrast -1/T1pre contrast) tissue / (1/T1post contrast -1/T1pre contrast) blood.
Based on the first pass perfusion data, MBVDCE and MBFDCE were obtained using Fermi deconvolution. The calibration factor (CF) was calculated as CF= MBVss / MBVDCE and used to calibrate MBF values (MBFcalib) according to: MBFcalib = MBFDCE *CF.
Perfusion data were obtained from five patients using a dual-bolus injection of 0.075mmol/kg Gadobutrol (Gadovist, Bayer, Germany) injected at 4ml/minute followed by a 20 ml saline flush using a Philips Achieva 3T (TX) system, equipped with a 32-channel cardiac phased array receiver coil (Philips, Best, Netherlands). Hyperaemia was induced with adenosine administered at 140 mcg/kg/min. First-pass perfusion images were acquired using a saturation recovery gradient echo method (TR/TE 3.0ms/1.0ms, flip-angle 15°; effective k-t SENSE acceleration 3.8, spatial resolution 1.2x1.2x10mm, saturation-recovery delay 120 ms). T1 images were acquired using a cardiac triggered Modified Look Locker Inversion Recovery (MOLLI) sequence(slice thickness 8 mm, FOV 388x320mm2, matrix 216x216, 11 different TI, range 90ms-3s). T1 was estimated through fitting of a three parameter exponential model SI(t) = A - B exp( t/T1*) and Look-Locker correction T1 = T1*((B/A) - 1).
The measurements of quantitative MBF agree closely with previously published gold-standard measurements by PET after calibration is performed. The addition of T1 steady state measurements to DCE measurements of MBF improve the accuracy of the measurement as inter-subject variability is taken into account.
The authors acknowledge financial support from the Department of Health via the National Institute for Health Research (NIHR) comprehensive Biomedical Research Centre award to Guys and St Thomas NHS Foundation Trust in partnership with Kings College London.
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.