Imaging

Question 1

Populations at high risk from imagine

Answer 1

Young
Females
Pregnant
Renal dysfunction
Thyroid illness

Question 2

Risk factors of radiation-linked cancer

Answer 2

1. Age
2. Sex
3. Site
4. Underlying risk (ie BRCA)

Question 3

Incidentalomas

Answer 3

Imaging studies that show abnormalities unrelated to the reason the test was ordered

Common in fine imaging

Causes an increase in follow-up testing (ie more imaging), some of which is invasive

Sensitivity correlates negatively with specificity

Question 4

X-ray

Answer 4

2D

Differentiates air, fat, bone, fluids/organs

Used most with chest, abdomen, bones

Minimal radiation

Question 5

Ultrasound

Answer 5

2D

Sound reflected produces image. Reflected back by air and hard objects. Partial reflection by organs. Unimpeded by fluid.

Commonly used for heart, gallbladder, pregnancy

Not toxic. Good for vulnerable groups

Question 6

Angiography

Answer 6

X-ray with intravascular contrast

Used more therapeutically (to stop embolism or dilate narrow arteries), than diagnostically (for atherosclerosis)

High radiation, contrast, risk of vessel puncture

Question 7

Nuclear medicine

Answer 7

Administer radiation-emitting material and then scan
2D or 3D

Differentiates tissue by radiation uptake

Commonly used for myocardium, PE, cancer/inflammation

Radiation (but less than that of CT)

Question 8

CT +/- contrast

Answer 8

3D

Differentiates based on Hounsfield units

Commonly used for trauma, brain tumors, abdomen
Contrast shows increased blood flow, inflammation

Fine-tune

High radiation, contrast

Question 9

MRI +/- gadolinium

Answer 9

3D
Differentiates tissue by H2O content

Commonly used for brain, spinal cord

Fine-tune

Can interrupt ferromagnetic material in patients, cause systemic renal sclerosis, or toxic in pregnant women