Respiratory Motion-Registered Isotropic Whole-Heart T2 Mapping in Patients With Acute Non-ischemic Myocardial Injury

Karolina Dorniak; Lorenzo Di Sopra; Agnieszka Sabisz; Anna Glinska; Christopher W Roy; Kamil Gorczewski; Davide Piccini; Jérôme Yerly; Hanna Jankowska; Jadwiga Fijałkowska; Edyta Szurowska; Matthias Stuber; Ruud B van Heeswijk

doi:10.3389/fcvm.2021.712383

Respiratory Motion-Registered Isotropic Whole-Heart T₂ Mapping in Patients With Acute Non-ischemic Myocardial Injury

Front Cardiovasc Med. 2021 Sep 29:8:712383. doi: 10.3389/fcvm.2021.712383. eCollection 2021.

Authors

Affiliations

¹ Department of Noninvasive Cardiac Diagnostics, Medical University of Gdansk, Gdansk, Poland.
² Department of Radiology, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.
³ Second Department of Radiology, Medical University of Gdansk, Gdansk, Poland.
⁴ Siemens Healthineers, Erlangen, Germany.
⁵ Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland.
⁶ Center for Biomedical Imaging (CIBM), Lausanne, Switzerland.

Abstract

Background: T₂ mapping is a magnetic resonance imaging technique that can be used to detect myocardial edema and inflammation. However, the focal nature of myocardial inflammation may render conventional 2D approaches suboptimal and make whole-heart isotropic 3D mapping desirable. While self-navigated 3D radial T₂ mapping has been demonstrated to work well at a magnetic field strength of 3T, it results in too noisy maps at 1.5T. We therefore implemented a novel respiratory motion-resolved compressed-sensing reconstruction in order to improve the 3D T₂ mapping precision and accuracy at 1.5T, and tested this in a heterogeneous patient cohort. Materials and Methods: Nine healthy volunteers and 25 consecutive patients with suspected acute non-ischemic myocardial injury (sarcoidosis, n = 19; systemic sclerosis, n = 2; acute graft rejection, n = 2, and myocarditis, n = 2) were included. The free-breathing T₂ maps were acquired as three ECG-triggered T₂-prepared 3D radial volumes. A respiratory motion-resolved reconstruction was followed by image registration of the respiratory states and pixel-wise T₂ mapping. The resulting 3D maps were compared to routine 2D T₂ maps. The T₂ values of segments with and without late gadolinium enhancement (LGE) were compared in patients. Results: In the healthy volunteers, the myocardial T₂ values obtained with the 2D and 3D techniques were similar (45.8 ± 1.8 vs. 46.8 ± 2.9 ms, respectively; P = 0.33). Conversely, in patients, T₂ values did differ between 2D (46.7 ± 3.6 ms) and 3D techniques (50.1 ± 4.2 ms, P = 0.004). Moreover, with the 2D technique, T₂ values of the LGE-positive segments were similar to those of the LGE-negative segments (T_2LGE-= 46.2 ± 3.7 vs. T_2LGE+ = 47.6 ± 4.1 ms; P = 0.49), whereas the 3D technique did show a significant difference (T_2LGE- = 49.3 ± 6.7 vs. T_2LGE+ = 52.6 ± 8.7 ms, P = 0.006). Conclusion: Respiratory motion-registered 3D radial imaging at 1.5T led to accurate isotropic 3D whole-heart T₂ maps, both in the healthy volunteers and in a small patient cohort with suspected non-ischemic myocardial injury. Significantly higher T₂ values were found in patients as compared to controls in 3D but not in 2D, suggestive of the technique's potential to increase the sensitivity of CMR at earlier stages of disease. Further study will be needed to demonstrate its accuracy.

Keywords: T2 mapping; acute non-ischemic myocardial injury; cardiac magnetic resonance(CMR); isotropic 3D imaging; respiratory motion correction.