- Workshop presentation
- Open Access
Effect of temperature and heart rate variability on Phantom T1 maps
© Vassiliou et al; licensee BioMed Central Ltd. 2015
- Published: 3 February 2015
- Quality Assurance
- Heart Rate Variability
- Quality Assurance Process
- Native Blood
- Myocardial Interstitial Fibrosis
Phantoms are increasingly being used for quality assurance when undertaking T1 mapping for myocardial interstitial fibrosis to ensure long-term stability of methods applied in patients e.g. against scanner alterations, across multi scanners and multi centers. We sought to investigate whether temperature and heart rate (HR) variability could influence Phantom T1/ECV as such a variation will need to be considered in the quality assurance process.
NiCl2-agarose gel phantoms  prepared in a standardised lab following a reproducible procedure as previously reported . For the HR variability 4 phantoms were used to model native and post-contrast T1 of blood and myocardium; They were imaged with a prototype 11 HB MOLLI 5(3)3 (Siemens prototype WIP448B) at low resolution (HR>90bpm) and high resolution (<90bpm) for RR 1400-490ms representing HR 43-122 bpm (Avanto, Siemens, 1.5T) at steady temperature. For the temperature variability 4 phantoms were prepared to mimic short and long T1 at 25oC (Phantom B1=1915ms, B2=1040ms, B3=530ms, B4=280ms). A water bath was prepared where were the phantoms were immersed, starting from a temperature of 35 oC cooling down to 15oC.
Heart rate variability
With increase in temperature the T1 of Phantoms B1 and B2 appeared to increase (B1 T1= 23.86 x Temp +1323, R2 = 0.99 and B2 T1= 6.27 x Temp + 883, R2 = 0.98). The shorter T1 phantoms (B3 and B4) did not show an association with temperature changes, in accordance with previously published work from 1987 on Ni2+ doped phantoms .
Heart rate variability has been shown to have a small but definite effect on the T1 values and ECV. Temperature variability can also affect the longer T1 values. Therefore, for successful T1 quality assurance with phantoms, both temperature and heart rate should be standardised. Such changes could further have implications for patients and new research is required to address this.
NIHR Cardiovascular Biomedical Research Unit of Royal Brompton & Harefield NHS Foundation Trust and Imperial 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/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.