Principles of Anatomy and Imaging Flashcards

1
Q

What are the 2 main specialities of radiology / medical imaging?

A
  1. Diagnostic imaging - imaging of the body and interpreting it to help find the pathology
  2. Interventional Radiology - surgical speciality, where interventions and treatments are done under imaging control, usually with the patient awake
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2
Q

Radiologist Vs Radiotherapist Vs Radiographer? Define the terms.

A

Radiologist - doctor specialising in interpretation of medical imaging

Radiotherapist - doctor specialising in providing radiotherapy to e.g. cancer patients

Radiographer - highly skilled technician, not medically trained, but takes the imaging

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3
Q

What are the different diagnostic imaging methods and group them into ionising and non-ionising radiation?

A

Ionising Radiation: X-rays and CTs (computer tomography), Nuclear medicine

Non-ionising Radiation: Ultrasound, MRI (magnetic resonance imaging)

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4
Q

What is the issue with ionising radiation?

Do the risks associated with ionising radiation impact the young and elderly equally?

A

Risk of inducing cancer after years of exposure

No, more significant impact in developing cancer later on if exposed to ionising radiaton young, that if exposed to ionising radiation when older (as shown on the graph)

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5
Q

How does an X-ray passing through the body produce an image?

A

The more X-rays that pass through, the blacker the image, the fewer the X-rays that pass through, the whiter the image

Different body tissues attentuate (block) X-rays differently i.e. most x-rays pass through air and fat = black image, 50% of x-rays pass through soft tissue = grey image, almost no x-rays pass through bone = white image

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6
Q

Often, on x-ray images, soft tissue looks very similar, and different tissues are difficult to differentiate.

What can be given to improve tissue contrast?

What are some risks associated with this method?

A

A contrast agent - enhances differences between tissues of similar densities e.g. blood vessels, can differentiate between pathological and normal tissue etc.

e.g. IV iodine, swallowed / injested barium

Some people are allergic to the contrast agents, and they may cause kidney damage

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7
Q

What is a CT scan and how does it work?

Why is the imaging produced from a CT scan better than a regular X-ray?

A

Uses X-rays to produce a cross-sectional image

X-ray tube spins around the patient, detector spins around the patient in an opposite tube, computer does the calculations to produce cross-sectional map of tissue densities

CT scan also shows where there is water present in the body and differentiates between different soft tissues

CT scans are also digital images that can be post-processed to emphasise different things e.g. bone, soft tissue, lung etc.

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8
Q

What are 3D reconstructions on the CT scans?

A

Where the cross-sectional images produced by the CT scanner are compiles to form a 3D image

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9
Q

What are ultrasounds and how do they work?

A

Imaging technique using high frequency sounds to make images - by measuring how quickly it takes for the sound to bounce back from the inside of the body to the outside

Uses a device called the transducer - it produces and detects the high frequency sound

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10
Q

What is an MRI and how does it work?

On who would it be unsafe to use an MRI?

A

Strong magnet, supercooled with helium that produces a strong magnetic field that causes the protons within a person’s body to align with it. Radiowave pulses are transmitted to the patient, which interacts with protons, and different tissues give different intensities of returned radiowaves (sounds), which produces the image

If a person has any metal in their bodies

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11
Q

How to differentiate between CT and MRI imaging of body parts?

A

Bone = white on CT, black on MRI

Fluid = dark grey on CT, black on T1 MRI, white on T2 MRI

Fat = black on CT, white on MRI

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12
Q

Hint: There is fat around the skull

Label on the diagram, which images are MRI (T1), MRI (T2) and CT:

A
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13
Q

What is nuclear medicine?

A

Involves nuclear medicine isotopes - uses radioactive tracers that emit radiation (radiation dose to patient)

Different tracers go to different organs / different parts of the body e.g. bone tracers, lung tracers, glucose tracers etc.

Images are made by using a gamma camera that picks up on the radiation coming out of the body

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14
Q

Why are nuclear medicines used?

A

Usually has a low resolution so not for fine details / anatomical details, but overall functioning e.g. looking to see if cancer has spread to the bone (metastatic cancer)

e.g. in this image: hotspots = metastatic cancer

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15
Q

Also known as a VQ scan (ventilation-perfusion scan)

Why are lung scans using nuclear medicine also a common practice in medicine? i.e. what does it look at?

A

To look at the ventilation and blood perfusion to the lungs - used to diagnose pulmonary embolisms (blood clot to the lung)

e.g. the top image shows normal blood flow and ventilation, the bottom image shows abnormal blood flow due to clots, but normal ventilation

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16
Q

Name another important nuclear medicine test that is used frequently in practice?

A

PET scan

17
Q

What does PET scan stand for?

How do PET scans work? (i.e. what do they look for in their imaging?)

What disease is it used for particularly?

A

Positron Emission Tomography

PET scans detect metabolic or ‘functional’ changes rather than structural changes

Effective in identifying the presence of cancer (diagnosis) and effectiveness of the treatment of cancer, i.e. if it is responding to treatment

18
Q

How does the PET scan work for detecting cancers?

A

Uses a radio-labelled glucose metabolite, which goes to areas that are quickly dividing - typical of cancers and / or infections

19
Q

Why are PET scans not solely used? What other scanning method is used with it?

A

PET is commonly used with CT scans - the images are then fused, which allows for better anatomical location of the cancers, therefore faster and more specific that the PET scan alone

20
Q

What is meant by the terms posterior and anterior?

What is meant by the terms lateral and medial?

What is meant by the terms cranial and caudal?

A

Posterior - closer to the back

Anterior - closer to the front

Lateral - away from the midline of the body

Medial - towards the midline of the body

Cranial - towards the head

Caudal - towards the lower end of the body

21
Q

Which side of an image scan corresponds to which side of the body?

A

The left of the image actually shows the right side of the body, and the right of the image actually shows the left side of the body

ALWAYS state which side of the body the abnormality is on (because we have two arms, two legs, two kidneys etc.)

22
Q

Looking at the feet and hands, why are posterior and anterior not used?

What terminology is used instead?

A

Because it depends on the way one looks at the feet and hands, although anaotmically, hand palms facing up is the default

Feet - dorsal and plantar

Hands - palmar / volar, dorsal, distal, and proximal

23
Q

What are the three anatomical planes?

A

Axial - tranverse cut through the body

Coronal - cut through the body from left to right

Saggital - cut thorugh the body from the front to back