Is T1-Mapping Truly Superior to Late Gadolinium Enhancement-Imaging in Demonstrating Myocardial Fibrosis in Myopathy- and Non-Myopathy Associated Noncompaction?

Background: Prior cardiac magnetic resonance (CMR) studies have reported abnormal T1 mapping, reflective of diffuse myocardial fibrosis, in patients with mitral valve prolapse (MVP) and ventricular arrhythmias. However, T1 mapping was derived from conventional Look-Locker sequences and/or obtained in selected MVP patients with severe mitral regurgitation (MR) and a clinical indication for CMR. Hypothesis: We hypothesize that extracellular volume (ECV) fraction, a marker of diffuse fibrosis derived from research-based, MOLLI T1 mapping sequences, is increased in MVP subjects with ventricular arrhythmias, even in the absence of significant MR. Methods: We performed CMRs in 10 consecutive, randomly selected MVP patients identified through our echocardiographic database, age/gender matched to 10 controls free of significant cardiac disease. All 10 MVPs underwent ambulatory EKG monitoring. CMR images were acquired using a GE 3.0T Discovery MR750w scanner. Global ECV fraction was calculated using pre- and 10 minutes post-contrast T1 times after administration of 0.1 mmol/kg of gadobutrol (Gadavist). Late gadolinium enhancement (LGE) was also obtained. MR fraction was quantified by velocity encoded CMR. Mild MR was defined as MR fraction < 16%. Results: MVP patients had significantly higher ECV fraction compared to controls (mean ECV (%) 32 ± 4 vs 20 ± 6, p = 0.0002), with 5/10 demonstrating non-sustained VT on ambulatory EKG monitoring. The majority (9/10 or 90%) of MVPs had mild or no MR (MR fraction < 16%), and 1/10 or 10% had moderate MR (MR fraction 18%). Only one individual in the MVP group had late gadolinium enhancement (LGE) in the papillary muscles. Conclusion: MVP with ventricular arrhythmias is associated with increased global ECV reflective of diffuse myocardial fibrosis, even in the absence of significant MR or LGE. Our preliminary findings highlight for the first time a primary interstitial derangement in MVP. Larger studies are needed to understand the mechanisms and prognostic significance of primary diffuse fibrosis in MVP.

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Cardiac MRI utilizing late gadolinium enhancement (LGE) and T1 mapping in the detection of radiation induced heart disease

10.21203/rs.3.rs-27113/v2 ◽

2020 ◽

Author(s):

Anthony Ricco ◽

Alexander Slade ◽

Justin Canada ◽

John Grizzard ◽

Franklin Dana ◽

...

Keyword(s):

Late Gadolinium Enhancement ◽

Myocardial Fibrosis ◽

Cardiac Mri ◽

T1 Mapping ◽

Myocardial Damage ◽

Smoking History ◽

Tumor Type ◽

Clinical Factors ◽

Gadolinium Enhancement ◽

Cross Sectional

Abstract Background and Purpose: Radiotherapy has been associated with late dose-dependent cardiovascular toxicity. In this cross-sectional pilot study, radiation dose distributions were correlated with areas of localized and diffuse myocardial fibrosis as measured by novel cardiac MRI (CMR) sequences including late gadolinium enhancement (LGE) and T1 mapping with the goal to identify early markers of myocardial damage.Materials and Methods: Twenty-eight patients with chest tumors including lung, breast, esophagus, and lymphoma underwent CMR per study protocol on average 46.4 months (range 1.7-344.5) after radiotherapy. Patients without pretreatment cardiac history were included if the volume of heart receiving 5 Gy or more was at least 10% (V5Gy≥10%). The association of LGE with cardiac dosimetric factors, clinical factors (e.g., tumor type, smoking history, BMI), , and T1 values was analyzed. Results: Cardiac maximum (Dmax) and mean dose (Dmean) equivalent to doses delivered in 2 Gy fractions (EQD2) were on average 50.9 Gy (range 6.2-108.0) and 8.2 Gy (range 1.0-35.7), respectively, compared to 60.8 Gy (40.8-108.0) and 6.8 Gy (1.8-21.8) among the 9 patients with LGE. Doses were not different between patients with and without LGE (p=0.16 and 0.56, respectively). The average T1 value of the left ventricle myocardium was 1009 ms (range 933-1117). No significant correlation was seen for heart Dmax and Dmean and T1 values (p=0.14 and 0.58, respectively). In addition, no significant association between clinical factors and the development of LGE was identified.Conclusions: No relation between cardiac doses, the presence of LGE or T1 values was observed. Further study is needed to determine the benefit of CMR for detecting radiotherapy-related myocardial fibrosis.

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