Imaging of circulatory disturbances

Question 1

types of anatomical vascular imaging

Answer 1

plain radiographs, catheter angiography, ultrasound, CT/MRI

Question 2

types of functional vascular imaging

Answer 2

radionuclide imaging, MRI functional imaging, ultrasound

Question 3

catheter angiography

Answer 3

vessel punctured and catheterised, sterile procedure, contrast injected using pump injector, rapid series of image acquisition

Question 4

challenges with vascular imaging

Answer 4

soft tissue contrast- can’t see important structures very well eg blood vessels, lumen of hollow viscera, functional significance of lesions, is treatment effective?

Question 5

when is vascular mapping useful

Answer 5

prior to intervention eg planning of aortic aneurysm repair, planning of lower limb arterial stenting/ bypass, prior to removal of living donor kidney. avoids cutting into wrong thing

Question 6

limitations of CT

Answer 6

won’t identify any small volume leaks, snapshot images so cannot exclude intermittent bleeding, can’t always differentiate between acute and chronic thrombosis, can be difficult to convey anatomy to non radiologists

Question 7

how do you visualise the vessels

Answer 7

IV contrast eg high density (iodine)

Question 8

problems with iodinated contrast

Answer 8

major allergic reactions, renal dysfunction, disturbance of thyroid metabolism, disturbance of clotting mechanism, seizures, PO, discomfort feels like peeing themselves, nausea (rare), metallic taste

Question 9

important considerations before using iodine contrast

Answer 9

asthma/atopy, previous contrast allergies, poor renal function, metformin- medication for diabetes

Question 10

contrast reaction rates

Answer 10

no history 1 in 10,000 other allergy 1 in 1000 death 1 in 40,000 asthma 2 in 1000

Question 11

most common ultrasound mode

Answer 11

B mode/ brightness mode/ 2D mode

Question 12

other modes on ultrasound used for

Answer 12

M mode/ motion mode. used to assess heart valve movement as well as chamber dimension and function

Question 13

what does red doppler imaging mean

Answer 13

shows direction of flow, flow in vessel is away from the probe. blue means towards

Question 14

doppler imaging used most commonly for

Answer 14

detection of DVT

Question 15

ultrasound contrast used for

Answer 15

characterising lesions, assessment of organ perfusion, delineating organ edge, alternative to Ct or MRI if unable to tolerate other forms of contrast. they are micro bubbles

Question 16

spiral CT

Answer 16

enables acquisition in single breath hold, less motion artefact better coordination with IV contrast, quicker, multiplanar images

Question 17

windowing

Answer 17

changes shade of pixels to make it easier for human eye to see. window level refers to the CT unit assigned as the midpoint of the scale