A NonInvasive Method to Assess Left

1
A Non-Invasive Method to Assess Left Right
Ventricular Function in Genetically Altered Mice
Abstract Transgenic mice are used to identify
characteristics of complex cardiovascular
diseases, and to accurately phenotype cardiac
functions. Magnetic Resonance Imaging (MRI)
assesses organ function in the human body
non-invasively. Transgenic mice which fail to
produce vasointestinal peptide (VIP), were used
to determine whether or not MRI would quantify
the physiological changes of the heart and
hemodynamic measurement changes. We introduce the
use of cardiac micro-MRI to track pressure-volume
relationship (PVR) for analysis of left and right
ventricular action in the murine heart. Data
revealed both ventricles were actively involved
during distressed cardiac state and therefore
micro-MRI can be used non-invasively to assess
cardiac state.
Figure F Hemodynamics
Methodology
Animals 80 C57BL/6 Wild-type mice Anesthetics-
Isoflurane allowed spontaneous
breathing Cannulation Femoral cannulation for
drug infusion. Hemodynamics Pressure conductance
transducer inserted into jugular
vein.
Cardiac Performance Physiological monitors
tracked temperature, respiratory rate and
pressure. PVR Analysis Volume analysis applied
an electrical conductance MRI catheter
Imaging Analysis Amira imaging software- 9.4
tesla and 20 cm horizontal magnet
Hemodynamic monitoring during cardiac image
acquisition proves loading conditions were not
factors in this experiment.
Introduction Current evaluations of cardiac
performance are limited because they induce
hemodynamic stress and loading conditions
underestimating diastolic and systolic volumes
Fox, 2003Pacher, 2004. Cardiac magnetic
resonance imaging (MRI) in conjunction with
Pressure-Volume Relationship (PVR) has been
established as one of the most reliable
techniques in determining systolic and diastolic
properties of the beating heart Ochiai,
1999Frank-Starlings Law of the Heart, 1912.
Results

• Discussion
• Novel technique to track physiological changes in
  cardiovascular diseases
• Analysis of chamber interactions can yield new
  treatments to treat cardiovascular diseases

Right- ventricular and central venous pressure
curves- Showed us changes in pressure during
distress Left- ventricular pressure-volume plot
reveals diastolic and systolic volumes
End-Systole
End-Diastole
Cardiac Cines- Volume/Press Chamber Volumes

• Conclusion
• microMRI quantified the distressed condition of
  the heart

Figures C D Cardiac images of systolic volume
pressure
Figures A B Cardiac images of
diastolic volume pressure
Figure C
Figure A
Figure E

• Future Experiments
• 3-D Analysis to establish global cardiac image
• This technique can be further developed for
  rapid and reliable cardiac phenotyping of
  genetically engineered animals.

Problem Can MRI convey to us through imaging the
interactions of the left and right ventricle and
hemodynamics in global cardiac distress?
Figure D
Figure B
Figure E Demonstrates cardiac MR images of five
chambers of the mouse heart