ECG & Pulse Doppler Systems For Cardiovascular Research on Mice
Electronics Contract R&D For Medical, Scientific, & Industrial Instrumentation
 
 
                                   
   

High Frequency Pulsed Doppler Transducers

                      
All of the transducers described below can be gas sterilized for chronic implantation or for use during sterile surgery. We often have epoxy cuffs in stock, but most probes can be built to order in two weeks.              
For prices, please visit our Price List page.
 
     
10 or 20 MHz Epoxy Flow Cuffs
Rigid epoxy cuffs are generally the preferred type for use in acute or chronically instrumented animals on vessels from 2 to 8 mm dia. Standard sizes, are 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, and 8.0 mm inside diameter. They are available with either of two methods for attaching the probe to the vessel: holes drilled near the slot for suture ties, or umbilical tape glued around the outside of the probe. Umbilical tape is usually used for chronically implanted probes which will not be reused, and sutures are best for acute or reusable probes because they are easier to replace and clean. Standard lead length is 30".  
 
         
 
10 or 20 MHz Silastic Flow Cuffs    
For smaller size vessels (0.5 to 2.0 mm) or where a more pliable probe is required transducers made from flexible silastic are available. Silastic probes have imbedded sutures for ties and form a full circle around the vessel when closed.  
 
     
10 or 20 MHz Curved Flow Patches    
For larger vessels or where a non-encircling probe is desired the ultrasonic crystal may be imbedded in a curved fabric/silastic patch for suturing to the vessel wall. This type of probe is often used on the aorta or pulmonary artery. The diameter of the curve must be specified, and it is usually better to be slightly oversized. This type of probe can be trimmed by the surgeon to fit the available exposure.  
     
   
     
5 MHz Segment Length Crystals    
The crystals consist of 2 mm discs of 5 MHz material with convex diverging epoxy lenses molded to each face to spread the sound beam. A 3 cm long piece of 20 gauge Teflon sleeving is placed around the leads to aid in inserting the crystal into the myocardium.  
     
 
     
10 or 20 MHz Epicardial Patches    
These probes are used to measure ventricular wall thickening with the displacement module. Two standard types are available: a 2 mm disc or square of 10 MHz material attached to a wire loop in the shape of a shamrock or clover leaf for use on large ventricles (dogs), or a similar 1 mm square of 20 MHz crystal for use on thin ventricles (rats). Each can be sutured to the epicardium.  
     
     
10 or 20 MHz Catheter Stub Probes    
These probes are used to sense flow in an exposed vessel by holding the probe against the side of the vessel. They are commonly used intraoperatively during reconstructive procedures to verify flow in anastomosed arteries and veins. They are available in 5, 6, or 7 French sizes, 4" long with 6' leads and can be used on vessels as small as 0.5 mm dia. They are lighter than needle mounted probes and less likely to be damaged if dropped.  
     
Tubing or Needle Mounted Probes  
For applications where a rigid, end-mounted transducer is required, we can mount crystals to the end of a piece of tubing or needle. The smallest size is a 16 gauge needle (recess for 1 mm dia 20 MHz crystal), and the largest is 1/4" brass tubing (recess for 5 mm dia 10 MHz crystal). We can also mold epoxy lenses to the crystal face to focus the sound beam. This type of focussed probe has been applied in mice to measure cardiac and peripheral blood velocity noninvasively.  
20 MHz Catheters  
Doppler catheters for research use in animals can be made as small as 3 French (1 mm dia) on a custom basis. For clinical applications, standard and custom catheters operating at 10 or 20 MHz are available from Millar Instruments.  
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