Chapter 88 - Cerebrovascular disease diagnostics

Question 1

Sensitivity and specificity of carotid imaging modality at different stenosis levels

Answer 1

TABLE 88.1

Question 2

Consensus panel gray-scale duplex criteria for ICA stenosis

Answer 2

TABLE 88.2

Question 3

AbuRahma adjustment on duplex ICA criteria

Answer 3

50-69 stenosis should change from 125-230 to 140-230

Question 4

Duplex in vertebrobasilar disease

Answer 4

only for flow direction extent of disease and anatomic information requires CTA/MRI

Question 5

Patients undergoing cabg should have duplex carotid/vert if these exist

Answer 5

1) LM disease 2) carotid bruit 3) previous CVA 4) IMA being used with weak radial pulse

Question 6

SVS screening suggestion for carotid

Answer 6

55 years old with CV risk 2014 US preventive service task force against this

Question 7

Chance of bilateral carotid body tumours

Answer 7

5%

Question 8

First line assessment for carotid body tumour

Answer 8

duplex

Question 9

Glomus vagale tumor differs from carotid body tumor

Answer 9

1) GVT does not splay carotid bifurcation 2) GVT causes displacement of distal ICA 3) GVT have vascular serpignous feeding vessels from proximal vagus nerve

Question 10

ICA stump syndrome

Answer 10

1) clot in ICA stump form thrombus 2) embolize to ECA 3) enter brain via supra- and infraorbital vessel collaterals

Question 11

Percentage of CEA done with duplex

Answer 11

95%

Question 12

Duplex alone for pre-op planning downside

Answer 12

1) tortuous or kinky distal ICA not seen 2) tandem lesions may be missed

Question 13

Nicolaides classification for plaque characteristics on duplex

Answer 13

TABLE 88.4 HALF

Question 14

Asymptomatic carotid stenosis and risk of stroke (ACSRS) identified US factors associated with stroke

Answer 14

1) plaque area <40 mm 1% vs > 80 mm 4.6% annually 2) JBA < 4 0.4% vs > 10 mm 5% 3) > 3 plaque ulcer 6% compared to < 3 0.6%

Question 15

imaging in carotid angioplasty and risk of stroke (ICAROS) study

Answer 15

GSM < 25 has 7.1% stroke GSM > 25 has 1.5% stroke

Question 16

Corrugation on ultrasound

Answer 16

Patch corrugation is wrinkling indicative of patch infection

Question 17

Duplex showing dampened waveform in proximal CCA suggest

Answer 17

inflow stenosis

Question 18

High resistance flow in distal ICA suggest

Answer 18

distal tandem lesion

Question 19

Contralateral occlusion or severe stenosis can cause this

Answer 19

ipsilateral higher PSV due to hyperemic collateralization overestimate degree of ipsilateral stenosis

Question 20

Subocclusion of carotid artery

Answer 20

1) low flow (< 20 cm/s) and does not return to normal calibre 2) if high flow and if duplex performed within 2 weeks of event, then need corroborative imaging

Question 21

Management of true subocclusion of carotid

Answer 21

no surgery no benefit not a risk predictor for subsequent stroke

Question 22

Limitation of CEMRA in carotid

Answer 22

1) soft tissue not well visualized 2) bony structure not present 3) calcium within plaque not well defined

Question 23

Time of flight MRA

Answer 23

1) better spatial resolution to measure stenosis severity 2) assess flow directionality in steal phenomena 3) cannot see COW or arch concurrently

Question 24

CEMRA key points

Answer 24

1) gadolinium (paramagnetic agent) 2) fewer artifact providing high resolution imaging of arch up to COW

Question 25

ABCD2 score

Answer 25

clinical scoring system to predict 48 hr and 7d risk of stroke 1) age 2) blood pressure 3) clinical presentation (0-2) 4) duration of symptoms (0-2) 5) diabetes max score 7

Question 26

risk of stroke based on ABCD2 and CT/MRI finding

Answer 26

TABLE 88.5

Question 27

contraindication to MRI

Answer 27

1) metallic implants 2) claustrophobia 3) obesity 4) chronic renal impairment

Question 28

CT PET in carotid disease

Answer 28

no evidence limited by inaccessibility, cost and lack of relevance

Question 29

Benefit of MDCTA in carotid disease

Answer 29

1) fast 5 sec arch to vertex 2) cheaper than CEMRA 3) 0.3 mm spacial resolution (0.8 for mra, 0.2 for dsa) 4) high quality 2d and 3d reformats 5) faster processing time 6) soft tissue visualization 7) rapidly demonstrate vascular anomalies 8) provides data on extent of calcification

Question 30

downside of MDCTA on vertebrobasilar imaging

Answer 30

good anatomy cannot show directionality

Question 31

Significance of carotid artery wall thickness

Answer 31

> 1 mm thickness associated with increased risk of stroke only seen on MDCTA

Question 32

When to perform CTA after CEA when pt has neurologic deficit

Answer 32

1) if completion DU or DSA was done and normal 2) if > 24 hours after surgery

Question 33

Stroke after DSA diagnosis in ACAS

Answer 33

2.6% death 0.06%

Question 34

MCA velocity above this can tolerate carotid ligation

Answer 34

TCD 15 cm/s

Question 35

Role of TCD in CEA

Answer 35

1) determine if spontaneous embolization occured during exposure 2) determine shunt function (3% don’t work on insertion) 3) determine MCA velocity > 15 cm/s (if not then raise BP) 4) determine if pt will thrombose ICA before operation completed