Radiology

Question 1

Densities in the body

Answer 1

By descending order: gas, fat, fluid, bone, metal

Question 2

How to tell whether a CT or MRI

Answer 2

Look for the bone: CT=cortical bone is white
MRI=cortical bone is DARK

Question 3

Angiogram= picture of vessels

Answer 3

complication: local hemorrhage emolus allergic death can be used for therappy as well as diagnosis

Question 4

Contrast agents

Answer 4

Barium for GI tract- swallowed or rectal admin
Water soluble material for tube placement
Intrauterine- hysterosalpingography
Intra-articular-arthography
Intrathecal-myelogram
Intravenous ie for contrast CT MRI
Intra-arterial-angiography

Question 5

CT Scan

Answer 5

Much better soft tissue resolution than plain films

High radiation dose

Can have severe contrast reactions, including death

Question 6

Different types of MRI scan

Answer 6

T1 (anatomical): fast to acquire, excellent structural detail (e.g. white and gray matter). T2 (pathological): slower to acquire, therefore usually lower resolution than T1. Excellent for finding lesions.

Question 7

(Left) Lateral radiograph and (Right) sagittal MRI of the knee. The MRI gives significantly better visualization of the soft tissues than does radiography.(Left)

Answer 7

Question 8

MRI

Answer 8

Excellent soft-tissue resolution

Not as good as CT for bone

No radiation dose

Noisy, claustrophobic

Question 9

How to tell whether a CT or MRI

Answer 9

Look for the bone

CT = cortical bone is WHITE

MRI = cortical bone is DARK

Question 10

Ultrasounds

Answer 10

•Uses high-frequency, sound waves•Principle is that used by bats and in submarines•Pulses of sound pass into the body, are reflected back to the probe and transformed into 2D picture

Question 11

Ultrasound Terms

Answer 11

•Ultrasound, sonogram, echo• Echogenic, increased echogenicity (hyperechoic), decreased echogenicity (hypoechoic), anechoic• Simple fluid e.g. in a cyst is anechoic (no echoes)• Complex fluid e.g. blood, pus has echoes• Solid tissue has varying degrees of echogenicity• Calcium, bone and air reflect the majority of sound and paper white

Question 12

Common Ultrasound studies

Answer 12

•OBGYN•Gallbladder – RUQ pain, gallstones etc•Abdominal – pain, mass, fluid•Thyroid – nodules, enlargement•Carotid – TIA, stroke•Guidance for biopsies

Question 13

Cardiac Ultrasound

Answer 13

•Ultrasound is a safe, accurate method of imaging cardiac anatomy and function

Question 14

Doppler Ultrasound

Answer 14

•Area of plaque in the carotid bulb producing visible narrowing of the vessel caliber•This would be associated with an increase in velocity of the blood at that site, which can be quantified with ultrasound

Question 15

Ultrasound

Answer 15

•No ionizing radiation•No known side-effects in levels used•User dependent•Little value in bone and gas containing organs •Very useful for point of care imaging

Question 16

Metastatic Prostatic Cancer

Answer 16

•A bone scan in a patient with prostate cancer, metastatic to the bones•The white areas in the bones represent areas of increased osteoblastic activity secondary to bone metastases

Question 17

Common nuclear medicine procedures

Answer 17

• Bone scan* – for metastatic disease
• Cardiac scan* – myocardial function
• HIDA scan* – for gallbladder function
• Thyroid scan* – thyroid nodules, treatment with radioactive iodine

Question 18

Nuclear Medicine

Answer 18

Uses ionizing radiation

Poor spatial resolution

Can show function as well as anatomy

PET/CT very important in oncology

Question 19

Plain fims

Answer 19

5 different densities: oGasoFatoFluidoBoneoMetal- increasing order

You need two or more images

Soft tissue differentiation is not good

Question 20

Radiographic Imaging

Answer 20

•Radiographic imaging is a 2-Dimensional representation of 3-Dimensional structures•You need at least two images at 90-degrees to each other