Doppler Flow
Velocity System

A Non-invasive Measure of Cardiovascular Physiology and Function

Imaging Gallery

Applications

Webinars

Parameters

Applications

Parameters

Transducers

Hardware

Past Webinars

System Overview

The Indus Doppler Flow Velocity System is a high-frequency, real-time pulsed Doppler measurement device with integrated data analysis software designed for measuring cardiovascular function in small animals. The high sampling rates grant excellent temporal resolution, making this the ideal system for studying fast heart rates and rapid blood accelerations present in small animals. Hardware components include the Pulsed Doppler Transceiver (PDT – a 10 & 20 MHz switchable dual channel system), Doppler Signal Digitizer (DSD), Doppler Workstation (DW), and handheld miniature probe(s).

Pulsed Doppler signals from the PDT are digitized at high sampling rates by the DSD and the workstation software. The acquired signals are processed using a fast Fourier transform algorithm and displayed as real-time grayscale Doppler flow velocity spectrograms. The workstation software permits recording and analysis of these spectrograms, ideal for report generation and publication purposes. This system has been successfully used in publications with mice, rats, bats, naked mole rats and other small animals. It is also capable of measuring blood flow velocities in larger animals using our implanted extra-vascular Doppler cuff probes.

Non-Invasive

Using a miniature handheld probe, flow velocities and differentials in various arteries, including the aorta, are reliably measured by placing the tip of the probe at a sharp angle relative to the direction of flow to be measured

Small Footprint

A powerful system that is both compact and easily transportable, allowing it to be scaled in larger facilities with ease or shared between cooperating labs without complication

Translational Data

Large bodies of literature support the translational relevance of rodent flow velocity data to clinical findings: study areas include cardiac function, myocardial perfusion, pressure overload, arterial stiffness, and more

Applications

Cardiac Function:
Systolic and Diastolic

Area

Flow Parameter

Coronary
Flow Reserve

Area

Flow Parameter

Arterial Stiffness
(Pulse Wave Velocity)

Area

Flow Parameter

Pressure-Overload
(Stenosis)

Area

Flow Parameter

Peripheral Artery
Disease and Perfusion

Area

Flow Parameter

Transducers

Hand-Held Transducer

For most applications, a noninvasive rigid probe with an end-mounted transducer is required. The active element is a 1.0 mm diameter (10 or 20 MHz) piezoelectric crystal recess-mounted at the end of the probe using epoxy molded into a lens to focus the sound beam.

This type of focused probe has been applied in mice and rats to measure cardiac and arterial blood velocity non-invasively. The probe can be held with a steady hand, or mounted in a micromanipulator which often assists with measurement accuracy and consistency.

Transducer

For chronic (implanted), extra-vascular applications or when the vessel cannot be accessed by a probe, a cuff transducer can be used. The cuff body is molded of flexible silicone and split lengthwise so that it can be slipped around the vessel. The piezoelectric crystal (10 or 20 MHz) is 1.0 mm diameter and mounted at a 45-degree angle using medical-grade epoxy.

Parameters

Surgical Monitoring
& Vital Sign Measurements

Peripheral Artery:
Carotid, Renal,
Femoral & Tail

Diastolic: Mitral
Inflow Velocity

E-peak & E-stroke velocity
E-time duration
E-acceleration & E-deceleration time
E-peak to ½ E-peak time
E-linear deceleration time & rate
A-stroke distance
A-time duration
E-A peak velocity ratio
Isovolumic contraction time
Isovolumic relaxation time

Other: Coronary, Transverse &
Abdominal Aorta

Hardware

Channels - Channels 1 and 2 = Doppler InPhase & Quadrature
Channel 3 = ECG Channels 4 – 8 = Auxiliary inputs
Input Range - ±10 V
Coupling - AC or DC software selectable
Sampling - 125 kHz per channel, 16 bits
Low Pass Filter - 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140 or 150 kHz (via Hardware)
Low Pass Filter - 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140 or 150 kHz (via Hardware)
High Pass Filter - 100, 200, 400, 600, 800, 1000, 1500 or 2000 Hz (Second or Fourth order, via Software)
Digital Signal Processor - 500MHz Dual Core Processor
Data Link to PC - USB 2.0 (480 Mb/s)
Power - 100-240 VAC Universal Adapter

Channels - Two, each switchable between 10MHz & 20MHz
Power - 110 VAC / 60Hz OR 220 VAC / 50Hz
Recorder Outputs - 2 from each channel (Phasic & Mean)
Audio Outputs - 2 from each channel (InPhase & Quadrature)
Audio Monitor - Amplifier & speaker selectable from any channel
External Ground - Intended for chasis grounding, if required
USB, RF/DEMOD - Future use
Transmitter Pulse Width - 0.4 μs
Receiver Pulse Width - 0.32 μs
Variable Range Gate - 1-10 mm (1-13 μs)
Velocity Outputs - 0.25 V/kHz simultaneous Phasic & Mean
Phasic Output Filter - Phasic (1 pole at 50 Hz), Damped (1 pole at 15 Hz) and Mean (2 poles at 0.25 Hz)
Probe Connection - Floating & differential (single-ended, differential)
Velocity Range - 1-100 cm/s at 0° angle, 2-200 cm/s at 60° angle
Electrical Zero - Front panel switches
Controls - Range adjustment, Polarity Switch, Filter
Ultrasound Frequency - 10MHz // 20MHz
Pulse Repetition Frequency - 31.25, 62.5, 125 KHz // 62.5, 125 KHz
Transmitter Output - 25 Vpp into 50 Ohm // 35 Vpp into 50 Ohm
Audio Bandwidth - ≈ 100 Hz to 15 KHz // ≈ 200 Hz to 25 KHz