Slide 1

EQUINE MEDICINE

Alternative Imaging Techniques: Ultrasound, MRI, CT Scan

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Ultrasound

Evaluation of soft tissueTransducer- Probe that uses sound waves to image tissuesEcho-Sound waves that bounce off tissues and travel back to the transducerConverted by a computer into a gray scale image

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Transducers

Sector Scan-Pie-shaped imagePhased Array-Crystals pulsed sequentiallyDelay between pulses

Annular Array-Crystals in ring Pulse directed through crystals

Use: Limited access areas

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Transducers

Linear Array Scan-Rectangular-shaped imageAlternate pulse on groups of crystalsUse: Unrestricted areas Equine tendons Transrectal imaging

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Patient Preparation

Clip or shave areaScrub area with shampoo & rinse thoroughlyWipe area with alcoholUse acoustic coupling gel to eliminate air

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Imaging

Digital Radiography

Basis for all digital images is the DICOM file format

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Digital Radiography

DICOM: Digital Imaging & Communications in MedicineStandard: Secure standardized images Reliable accurate images Hold up under legal scrutiny

Other formats: jpeg, tiff, gif, png, psgNeed viewing program to use!!!!

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Digital Radiography

Image Quality: Hardware & software usedImagine detectorImage processingMonitor

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Computed Radiography

Replaces film, intensifying screen & cassette with an imaging plateProcessor is replaced with a digital imaging readerAdvantages: Digital imaging Retrofit of equipment Mobile Relatively inexpensiveDisadvantages: Imaging plate needed Single plate development Image reader needed

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Direct Digital Radiography

Radiographic film & cassette are replaced with an imaging sensorAdvantages:Digital imagingPartial retrofit of equipmentImmediate image generationNo processingNo imaging plateImage quailtyDisadvantages:CostSensor attachment by wire

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Computed Axial Tomography

Produces cross-sectional imagingX-ray beam is highly collimated, & rotates around animal to obtain image

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Computed Axial Tomography

Voxel-Density of a small volume within a patient Projected onto screen or film to produce imageAdvantages: Detects small tissue density differences Highly detailed image produced Ability to see deep/small changesDisadvantages: Cost Requires general anesthesia Gantry opening may limit patient access

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Magnetic Resonance Imaging

Uses hydrogen protons in the body to produce a detailed imageAnimal placed in a magnetic fieldMagnet aligns hydrogen protons in the same directionPulse of high energy radio frequency disrupts alignmentRadiofrequency is released as atoms realign-imaged produced

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Magnetic Resonance Imaging

System Types:High Field System 1.0 T magnetic field Higher detail image Fast image production General anesthesia requiredLow Field System