17 Case Subclavian

7/29/2019 17 Case Subclavian

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Case Study

Multislice CTDiagnosis of Subclavian Artery Stenosis



Multislice CTDiagnosis of Subclavian Artery Stenosis

A 54-year-old female presents with

lightheadedness, syncope, and

slurred speech. The patient was

admitted for stroke vs transient

ischemic attacks.

Initial head CT without contrast was

negative for CVA or hemmorhage.

Bilateral carotid doppler study was

performed which revealed no hemo-

dynamically significant stenosis.

However, there was retrograde flow

in the left vertebral artery and ante-

grade flow in the right.

Chest CTA was performed to evaluate

the left subclavian artery for surgial

disease in a patient with subclavian

steal.

2 Case Study

Technical Data

Patient positioning Head first/supine, arms down

Scan range From below the aortic arch through the

carotid bifurcations

Scan mode ECG gated spiral CT

kV 120 kV

Effective mAs 425 mAs

Rotation time 0.5 s

Slice collimation 4 x 1 mm

Slice width 1.25 mm

Table feed/rotation 1.8 mm

Pitch 1.8

Scan direction Caudal-cranial

Reconstruction increment 1 mm

Kernel B20Retrospective ECG gating -400 ms

History

Contrast medium 370 Isovue

I.V. administration 20g i.v. in the right antecubital vein

Volume 150 cc

Flow rate 3 cc/s

Start delay 30 s

Post processing

[1] Multiple thin sliding maximum intensity projections (MIP) on the

Wizard: Sagittal and coronal, 10 mm thick with a reconstruction spacing

of 1.5 mm. The MIPs were angled to follow the course of the vesssel.[2] Volume rendering on the SOMATOM Volume Zoom.

[2] Coronal (A) andsagittal (B) MIP images

show the stenosis(arrowheads) proximal

to the origin of thevertebral artery in the

thyrocervical trunk

A B



Results

It has been my experience when

performing CTA of the subclavian

artery that cardiac pulsations can

cause artifacts that can mimic

stenosis or thrombus. The subclavian

artery is seen very well but the actual

junction of the subclavian and aorta

(or carotid and aorta) can be blurred.

Comments

CT Angiogram of the left subclavian

artery revealed a high grade stenosis

just proximal to the origin of the

vertebral artery in the thyrocervical

trunk. This finding reflects the etio-

logy for the patient‘s subclavian steal

syndrome.

As another example shown in [4]

that the scan was also performed for

subclavian steal but the results were

inconclusive due to the cardiac pulsa-

tion artifact. On the AP projection

you can see what appears to be a

stenosis at the base of the Lt. sub-

clavian artery [4 A]. This is a false

positive finding. Subsequent conven-

tional arteriography demonstrated a

patent Lt. subclavian artery without

stenosis. The lateral projections show

the pulsations and it is very difficult

to diagnose any stenosis [4 B].

With HeartView CT, we can get a

motion free angio image of the aortic

arch and subclavian artery, which

clearly shows the area of stenosis.

There are no suspicious areas where

the radiologist would question:”Is that motion artifact or real patho-

logy?” Currently we are performing

this kind of study in our clinical

routine applications, and we are also

in the process of optimizing the dose

for such an application.

[3] Axial imageshows an area of stenosis (arrow) in

the medial aspect of the left subclavianartery

[1] VRT imagesconfirms stenosis(arrows)

[4] Coronal (A)and sagittal (B)

MIP images showcardiac pulsationartifacts makingthe diagnosis of

stenosis difficult

A B



Order No. A91100-M2100-A535-1-7600

Printed in Germany

CC 63535 WS 03025.

Author:

Chris Deangelo RT (R), (CT)

Imaging Coordinator

CT Department

Alamance Regional Medical Center

Burlington, NC

USA

The information presented in this case report is for

illustration only and is not intended to be relied upon

by the reader for instruction as to the practice of

medicine. Any health care practitioner reading this

information is reminded that they must use their own

learning, training and expertise in dealing with their

individual patients. This material does not substitute

for that duty and is not intended by Siemens Medical

Solutions Inc., to be used for any purpose in that regard.

Note:

Original images always lose a certain amount of detail

when reproduced.

Siemens AG, Medical Solutions

Henkestr. 127, D-91052 Erlangen

GermanyTelephone: ++49 9131 84-0

Internet: SiemensMedical.com

Siemens AG, Medical Solutions

Computed Tomography

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Telephone: ++49 9191 18-0

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17 Case Subclavian