intro to equine diagnostic imaging

Out of portable vs gantry mounted X-ray machine which provides a greater exposure

Gantry mounted - higher kVp and mAs

X-ray machine settings - kVp

Speed of electrons (energy)

X-ray machine settings - mA

Number of electrons released

X-ray machine settings - S

Time

Film : focal distance meaning

Distance of machine from animal

How to increase contrast of image

Increase mA (more photons)

Name of unique code of digital image

DICOM

Film reading / reporting

State area, critique quality, radio graphic report (recognition / search phase, descriptive/ report phase, interpretation/ DDx phase)

How to describe film quality

Positioning, collimation, contrast, exposure, labelling, artefacts

What to state in recognition phase of report

Visible structures, abnormal vs normal findings, normal variations

What to state in descriptive phase of report

Size, shape, position, number, marination, opacity

What to state in interpretation phase of report

History, signalment, clinical signs, diagnostic tests

Frequency range for ultrasound

2.5-14mHz

Types of ultrasound probes

Linear, sector, phased-array

Patient prep for ultrasound

Clip + clean skin, ultrasound gel, standoff, alcohol, quiet, still, darkened area

Describing lesions in ultrasound

Shape, size, position, number, marination+ fibre allignment, echogenicity

Nuclear medicine (gamma scintigraphy)- purpose + how does it work

Radioisotope Tc 99M bound to hydroxyapatite IV injection → binds to actively remodelling bone (acts like Ca) → gamma ray detection by Geiger counter

Nuclear medicine (gamma scintigraphy)- Phases of scanning

1- blood pool, immediate

2- soft tissue, 2-15min

3- bone, 2-3hrs, bound to hydroxyapatite crystals

Nuclear medicine (gamma scintigraphy)- Where does the binding increase

Inflammation, bone repair/remodelling, osteomyelitis, neoplasia

Nuclear medicine (gamma scintigraphy)- How to quantify image

Colour (more intense = more gamma rays detected)

Compare paired (L+R) images

Nuclear medicine (gamma scintigraphy)- How to do safely

Minimise contact with horse, gloves, contain urine + faeces, monitor exposure

When to do MRI

After basic imaging to help advance/find diagnoses

Nuclear medicine (gamma scintigraphy)- Advantages

Sensitive

Nuclear medicine (gamma scintigraphy)- Disadvantages

Not useful if soft tissues, not specific

MRI advantages

Detail, specific, sensitive

MRI disadvantages

Harder in prox limb, misuse

Which parts can be investigated with standing CT

Heads, cervical spine

Which parts can be investigated with GA CT

Dis limbs, head, cervical spine

Colour of gas on ultrasound

White

Colour of fluid on ultrasound

Black