The Role of 1.5 Tesla MRI and Anesthetic Regimen Concerning Cardiac Analysis in Mice with Cardiomyopathy

Abstract

Accurate assessment of left ventricular function in rodent models is essential for the evaluation of new therapeutic approaches for cardiac diseases. In our study, we provide new insights regarding the role of a 1.5 Tesla (T) magnetic resonance imaging (MRI) device and different anesthetic regimens on data validity. As dedicated small animal MRI and echocardiographic devices are not broadly available, we evaluated whether monitoring cardiac function in small rodents with a clinical 1.5 T MRI device is feasible. On a clinical electrocardiogram (ECG) synchronized 1.5 T MRI scanner we therefore studied cardiac function parameters of mice with chronic virus-induced cardiomyopathy. Thus, reduced left ventricular ejection fraction (LVEF) could be verified compared to healthy controls. However, our results showed a high variability. First, anesthesia with medetomidine, midazolam and fentanyl (MMF) led to depressed cardiac function parameters and more variability than isoflurane gas inhalation anesthesia, especially at high concentrations. Furthermore, calculation of an average ejection fraction value from sequenced scans significantly reduced the variance of the results. To sum up, we introduce the clinical 1.5 T MRI device as a new tool for effective analysis of left ventricular function in mice with cardiomyopathy. Besides, we suggest isoflurane gas inhalation anesthesia at high concentrations for variance reduction and recommend calculation of an average ejection fraction value from multiple sequenced MRI scans to provide valid data and a solid basis for further clinical testing.

Soluble Vascular Cell Adhesion Molecule-1 (VCAM-1) as a Biomarker in the Mouse Model of Experimental Autoimmune Myocarditis (EAM)

“…We finally evaluated cardiac function parameters including LVEF and SVI. Despite a clear deterioration of EAM mice in comparison to healthy controls of a previous study,[ 23 ] cardiac function parameters did show a moderate but not significant correlation with sVCAM-1.…”

Activation of the MET receptor attenuates doxorubicin‐induced cardiotoxicity in vivo and in vitro

“…CINE MRI was carried out by using an electrocardiographic‐triggered FLASH CINE gradient‐spoiled gradient echo sequence with the following parameters: flip angle = 15°; repetition time = 8 ms; echo time = 2.5 ms; field of view = 35 mm × 35 mm; matrix size = 192 × 192; in‐plane spatial resolution = 0.182 × 0.182 mm 2 per pixel; slice thickness = 1 mm; number of average = 6; and heart cycle sampled with 20 images. After the acquisition, morphological parameters of interest for cardiac function were measured in diastole and systole (Bakermans et al, 2015; Grabmaier et al, 2014). In particular, left end diastolic volume (EDV) and left end systolic volume (ESV) were manually measured.…”

Test-retest reproducibility of cardiac magnetic resonance imaging in healthy mice at 7-Tesla: effect of anesthetic procedures

“…also observed this effect and demonstrated that isoflurane anesthesia was associated with increased myocardial blood flow in Wistar rats compared with pentobarbital 16 . However, accumulating evidence favors the use of isoflurane in rodent cardiac imaging studies, such as a preclinical report highlighting the superiority of isoflurane anesthesia based on lower inter-subject variability of CMR left ventricular parameters compared with intraperitoneal anesthesia with MMF combination (medetomidine, midazolam and fentanyl) 20 . Our results provide additional evidence for the use of isoflurane to reduce the test-retest variability of left ventricular volume assessment when two CMR examinations are performed one week apart in the same healthy animals.…”