Abstract
Background: Advanced measures of cardiac function are increasingly important to clinical assessment due to their superior diagnostic and predictive capabilities. Cine DENSE cardiovascular magnetic resonance (CMR) is ideal for quantifying advanced measures of cardiac function based on its high spatial resolution and streamlined post-processing. While many studies have utilized cine DENSE in both humans and small-animal models, the inter-test and inter-observer reproducibility for quantification of advanced cardiac function in mice has not been evaluated. This represents a critical knowledge gap for both understanding the capabilities of this technique and for the design of future experiments. We hypothesized that cine DENSE CMR would show excellent inter-test and inter-observer reproducibility for advanced measures of left ventricular (LV) function in mice. Methods. Five normal mice (C57BL/6) and four mice with depressed cardiac function (diet-induced obesity) were imaged twice, two days apart, on a 7T ClinScan MR system. Images were acquired with 15-20 frames per cardiac cycle in three short-axis (basal, mid, apical) and two long-axis orientations (4-chamber and 2-chamber). LV strain, twist, torsion, and measures of synchrony were quantified. Images from both days were analyzed by one observer to quantify inter-test reproducibility, while inter-observer reproducibility was assessed by a second observer's analysis of day-1 images. The coefficient of variation (CoV) was used to quantify reproducibility. Results: LV strains and torsion were highly reproducible on both inter-observer and inter-test bases with CoVs ≤ 15%, and inter-observer reproducibility was generally better than inter-test reproducibility. However, end-systolic twist angles showed much higher variance, likely due to the sensitivity of slice location within the sharp longitudinal gradient in twist angle. Measures of synchrony including the circumferential (CURE) and radial (RURE) uniformity of strain indices, showed excellent reproducibility with CoVs of 1% and 3%, respectively. Finally, peak measures (e.g., strains) were generally more reproducible than the corresponding rates of change (e.g., strain rate). Conclusions: Cine DENSE CMR is a highly reproducible technique for quantification of advanced measures of left ventricular cardiac function in mice including strains, torsion and measures of synchrony. However, myocardial twist angles are not reproducible and future studies should instead report torsion.
Original language | English |
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Article number | 71 |
Journal | Journal of Cardiovascular Magnetic Resonance |
Volume | 15 |
Issue number | 1 |
DOIs | |
State | Published - 2013 |
Bibliographical note
Funding Information:This work was supported by a Postdoctoral Fellowship through the Ruth L. Kirschstein National Research Service Award (5T32HL91812-05), the NIH Director’s Early Independence Award (1DP5OD012132-01), a pilot grant from an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the NIH (8 P20 GM103527-05), the University of Kentucky Cardiovascular Research Center, grant number UL1RR033173 [TL1 RR033172, KL2 RR033171] from the National Center for Research Resources (NCRR), funded by the Office of the Director, National Institutes of Health (NIH) and supported by the NIH Roadmap for Medical Research, and contributions made by local businesses and individuals through a partnership between Kentucky Children’s Hospital and Children’s Miracle network. The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding sources.
Keywords
- Cardiovascular magnetic resonance
- DENSE
- Heart
- Mice
- Reproducibility
- Strain
ASJC Scopus subject areas
- Radiological and Ultrasound Technology
- Radiology Nuclear Medicine and imaging
- Cardiology and Cardiovascular Medicine
- Family Practice