Myocardial Extracellular Volume Measurements using a shorter post-contrast T1 mapping delay time for Diagnosis of Cardiac Amyloidosis in 3.0T Cardiac Magnetic Resonance

Yan Yi¹, Lu Lin¹, Yining Wang¹, Jian Cao¹, Lingyan Kong¹, Jing An², Tianjing Zhang², and Bruce Spottiswoode³

¹Peking Union Medical College Hospital, Beijing, China, People's Republic of, ²Siemens Shenzhen Magnetic Resonance Ltd., beijing, China., Beijing, China, People's Republic of, ³MR Research and Development, Siemens Healthcare, Chigago, IL, United States

Synopsis

The study aim was to explore the diagnostic value of ECV for cardiac amyloidosis calculated by 5 min post-contrast T1-mapping compared with conventional 15-20 min post-contrast T1 mapping. The results showed ECV calculated by 5min post-contrast T1 mapping had similarly promising diagnosis value for cardiac amyloidosis compared with 15-20 min post-contrast T1 mapping.

Purpose: Cardiac involvement in systemic light-chain (AL) amyloidosis is caused by the extracellular deposition of misfolded AL immunoglobulin and carries a poor prognosis. Cardiac magnetic resonance (CMR) T1 mapping and extracellular volume (ECV) measurements have been proved to have advantages over late gadolinium enhancement (LGE) for early diagnosis and quantification of amyloid burden [1]. Previous research showed a dynamic equilibrium between myocardial and blood gadolinium concentrations could be reached from 5 to 20 minutes (min) after gadolinium injection [2]. The aim of this study was to explore the diagnostic value of ECV for cardiac amyloidosis calculated by 5 min post-contrast T1-mapping compared with conventional 15-20 min post-contrast T1 mapping.

Methods: The study received local ethical approval and all patients gave written informed consent. The amyloidosis group included patients diagnosed of systemic AL amyloidosis with histology proof and definite clinical cardiac involvement. The control group included patients with neither clinical evidence of infiltrative cardiomyopathy nor CMR myocardial LGE. All the patients underwent a standardized bolus contrast-enhanced CMR (3.0T) imaging composed of native, 5min and 15-20min post-contrast T1 mapping (modified Look-Lockers inversion recovery sequence) in identical slices. ECV calculation using the 5min (ECV1) and 15-20min (ECV2) post-contrast T1 mapping were accomplished semi-automatically by dedicated software. Native T1, ECV1 and ECV2 value of identical region of interest (ROI) in interventricular septum were compared between amyloidosis group and control group by Mann-Whitney test. Paired ECV1 and ECV2 values in identical ROI were compared by Wilcoxon test.

Results: The amyloidosis group recruited 26 patients (mean age 54±10 years, 13 men).11(42%) of them had a positive endomyocardium biopsy confirmed by Congo red histology. The control group included 18 patients (mean age 41±12 years, 12 men). Myocardial native T1, ECV1 and ECV2 all significantly elevated in amyloidosis group compared to control group (1464±114ms vs. 1267±40ms, 0.54±0.10 vs. 0.26±0.03, 0.51±0.09 vs. 0.26±0.03, p=0.000). In amyloidosis group, ECV1 was slightly higher than ECV2 (0.54±0.10 vs. 0.51±0.09, p=0.002), while in control groups ECV1 and ECV2 showed no significant difference (0.26±0.03 vs. 0.26±0.03, p=0.925).

Conclusions: Myocardial native T1, ECV calculated by 5min and 15-20min post-contrast T1 mapping all significantly elevated in cardiac amyloidosis patients in 3T CMR. ECV calculated by 5min post-contrast T1 mapping showed similarly promising diagnosis value for cardiac amyloidosis compared with 15-20 min post-contrast T1 mapping.

Acknowledgements

No acknowledgement found.

References

1. Sanjay M. Banypersad, et al. Circ Cardiovasc Imaging. 2013;6:34-39.

2. A. Barison, et al. J Intern Med. 2015 May;277(5):605-14.

Figures

LGE, native T1 mapping, ECV1(calculated by native and 5min post-contrast T1 mapping) and ECV2 map(calculated by native and 15-20min post-contrast T1 mapping) images in identical short axis 2 chamber slice of a endomyocardial biopsy proved cardiac amyloidosis patients. Interventricular septum late enhancement was uncertain in LGE image, but region of interest measurements showed significantly elevated native T1(1466ms), ECV1(0.55) and ECV2(0.55) of myocardium.

LGE, native T1 mapping, ECV1(calculated by native and 5min post-contrast T1 mapping) and ECV2 map(calculated by native and 15-20min post-contrast T1 mapping) images in identical short axis 2 chamber slice of a control goup patients. There was no prominent myocardial late enhancement.Interventricular septum region of interest measurements showed a relatively low native T1(1204ms) and similarly normal ECV1(0.237) and ECV2(0.241).

Proc. Intl. Soc. Mag. Reson. Med. 24 (2016)

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