Small Animal Echocardiography Core Facility

EmailEmail    |   Bookmark Page Bookmark  |   RSS Feeds RSS  |   Print Page Print  

 Services 


Echocardiography is the cornerstone of the phenotyping process. Its highly versatile nature makes it the non-invasive tool of choice. This form of non-invasive assessment is ideal for performing serial evaluations of cardiac function or real-time monitoring during and after pharmacological or therapeutic intervention. Echocardiography has the versatility that allows for rapid and comprehensive evaluation of myocardial function, valvular and vascular structure in animal models. Protocols are adaptable to the needs of the investigator.2D Short Axis Left Ventricle

 

A comprehensive small animal echocardiogram includes:

• 2D short- and long-axis cine loops of the heart from the parasternal view
• 2D guided M-mode image of the left ventricle
• Doppler recordings of trans-mitral and aortic valve velocities from the apical view
• Doppler tissue recordings of mitral annular and left ventricular segmental wall motion velocities
 
 
 

Services:

PRIMARY STUDIES

1. Screening Echocardiogram: Non-invasive single transthoracic cardiac ultrasound exam performed under anesthesia that includes 2D and M-mode images of the left ventricle and Doppler recordings of trans-valvular flow indices.

  Examples of Normal Left Ventricle Function

  Data provided at the study end: Spreadsheet with various echo parameters including: 

  • LV Fractional Shortening
  • LV Ejection Fraction
  • LV Volumes
  • LV Stroke Volume
  • Septal Thickness in Diastole
  • Posterior Wall Thickness in Diastole
  • LV Dimensions in Diastole and Systole
  • LV Mass
 
2. Serial Screening Echocardiogram: Echocardiograms that must occur on specific days and must be repeated on the same animal at a specific later date. Includes all the analysis of a screening echocardiogram at each echo date.
 
3. Post Myocardial Ischemia/Infarction Echocardiogram: When regional wall motion abnormalities are expected, then the echocardiographic study requires more than M-mode and 2D images. For these echocardiograms, we will include segmental wall motion analysis with 2D speckle tracking and strain analysis.
 
 
   Data provided at the study end: Spreadsheet with various echo parameters. Data on spreadsheet will include segmental wall strain values, LV end diastolic and systolic volumes, ejection fraction and heart rate.
 
4. Post-surgical echocardiograms: Full echocardiograms to document the outcome of a specific surgery other than myocardial infarction (such as TAC, AAB or NAB). This echo may include 2D and M-mode images and analysis of the left ventricle, or Doppler recordings of trans-valvular flow indices (gradients), Doppler recordings (gradients) across the aortic constriction. Analysis of diastolic function may be included for an additional cost.

   Data provided at the study end: Spreadsheet with various echo parameters. Data on spreadsheet will include gradient measurements at the site of constriction. 

 

SPECIALTY STUDIES

5. Emergency Echocardiograms: Previously unscheduled echoes that are necessary to do immediately because the animal is in newly discovered end-stage heart failure and may expire, or other emergent conditions. This also includes non-emergent studies that need to be performed with less than 2 business days notice.

   Data provided at the study end: Spreadsheet with various echo parameters.

 

6. Vascular-Aorta Imaging: Ultrasound scanning is used to delineate structural and functional abnormalities of the aorta or other vessels. Includes an analysis of these parameters and data reporting.
 

   Data provided at the study end: Customized depending upon discussion with PI.

 

7. Non-Cardiac Scanning: Includes ultrasound imaging of other organs and vasculature including renal, vascular and embryo ultrasounds.

   Examples of Rat Renal Ultrasound

   Data provided at the study end: Customized depending upon discussion with PI.

 

8. Customized Echocardiography

  Includes studies that the core staff and the PI have discussed in detail and that are not offered on a routine basis. Analysis and data reporting will be included. 

 

SPECIALTY ANALYSIS

9. Strain  Analysis of Left Ventricle: 2D speckle tracking echocardiography is a novel technique that enables the assessment of myocardial strain through the analysis of speckle motion inherently present in a standard, 2D echocardiographic image. This technique is angle independent, preload independent, not affected by tethering between segments and less operator dependent. This technique has been validated in experimental and human studies and found to correspond well to established “gold standard” techniques.

  Examples of Strain Imaging

 
  Why use strain imaging for your study?
  1. Strain has increased sensitivity in detecting LV systolic dysfunction when compared to conventional LV function analysis. (i.e. ejection fraction and  fractional shortening)
  2. Strain analysis is better suited for regional wall motion abnormalities
  3. Speckle tracking-derived strain correlates with the degree of cardiac fibrosis

   Data provided at the study end: Spreadsheet with quantitative regional and global strain values.

 

10. Strain Rate Analysis of Left Ventricle

  Why analyze strain rate for your study?

  1. Diastolic strain rate may be used as an additional surrogate of ventricular fibrosis and segmental relaxation abnormalities.
  2. By providing insight into regional diastolic function, segmental diastolic strain rate can readily uncover the presence and extent of regional ischemia and viability.

   Examples of Strain Rate Imaging

   Data provided at the study end: Spreadsheet with quantitative regional and global strain rate values. 

 

11. Doppler Analysis of Diastolic Function, Transvalvular Velocities and Valve Regurgitation: We routinely assess LV diastolic function in small animals based on three Doppler-derived parameters: E/E’, Vp, and IVRT/RR. Another index is E/A; however, distinct E and A peaks are generally not discernible in anesthetized rodents. Doppler is also used to assess transvalvular velocities and regurgitant lesions.
 
 
   Data provided at the study end: Spreadsheet with various echo parameters.
 

Note: Mitral inflow indexes (E, A, and E/A) are complex and subject to misinterpretation because these parameters are dependent on not only intrinsic relaxation properties of the LV but also on other factors such as HR, the volume loading conditions, left atrial–LV pressure gradients, and LV compliance. Although the ratio of peak early transmitral flow velocity (E) to the peak early myocardial tissue velocity (E’) is a more robust indicator of LV diastolic dysfunction, it too has its shortcomings. E’ measures the velocity of myocardial displacement as the LV expands during diastole and can, therefore, be considered a surrogate marker for tau (the time constant of relaxation). Likewise, Vp is relatively independent of changes in preload and heart rate and also closely reflects tau.

 

 ADDITIONAL SERVICES

 12. Real time monitoring of cardiac procedures:  For example, visualization of the heart during direct myocardial injection.

webmaster@mcw.edu
© 2014 Medical College of Wisconsin
Page Updated 11/12/2013