Transcranial Doppler(TCD) summary and velocities numbers for exam 2

what are the Flow characteristics

Velocity, Turbulent flow, Pulsatility, Systolic upstroke

what angle degree is assumed

Mean velocity is calculated=

Differences between intracranial artery velocities more important than?

Differences between intracranial artery velocities more important than absolute values recorded from an individual

Transtemporal Window  Technique, patient is postion how? how is the head?

transducer placed on what bone, how is the psotion like describe it?

window divided into 3 areas what are those areas called?

Patient supine- head straight 

Transducer placed on temporal bone superior to zygomatic arch and anterior to the ear 

Thinnest portion of the skull 

Window divided into 3 areas 

Anterior, middle, and posterior

Transtemporal Window  Technique

how much gel should you use and why?

angle transducer for what and may require what

allows what visualization of what circulation

Technique 

Generous gel ensures good transducer to skin contact 

Angle transducer to optimize Doppler angle – may require elevation from skin surface 

Allows simultaneous visualization of anterior and posterior circulation

Transtemporal Window  Image orientation  Ipsilateral hemisphere is at the “where” of monitor-Contralateral hemisphere is at the where

Anterior to the right or left and posterior to the right or left

Transtemporal Window  Image orientation  Ipsilateral hemisphere is at the “top” of monitor-Contralateral hemisphere is at the bottom

Anterior to the left and posterior to the right

Transtemporal Window – MCA

Depth=

Flow direction

Mean velocity-

Angle

Courses adjacent to

Branches usually in what color, but may be what -why?

Depth 30 – 60 mm 

Flow direction – Antegrade; toward 

Mean velocity- 55 + 12 cm/sec 

Angle – anterior and superior 

Courses adjacent to sphenoid wing 

Branches usually in red, but may be blue as they curve away from transducer

Transtemporal Window – TICA

Depth

Flow Direction

Mean velocity

Angle

what image artifact and occur due what

Depth- 55-65 mm 

Flow Direction – toward transducer (red) 

May be bidirectional 

Mean velocity- 39 + 9 cm/sec 

Angle – anterior inferior 

Mirror image artifact may occur due to adjacent bone

Transtemporal Window – ACA

Depth

Flow direction

whats the butterfly look direction

Mean velocity

what should you do to the PRF, and why

angle

Depth- 60-80 mm 

Flow direction – retrograde / away 

ACA/MCA bifurcation toward and away (VT pg 242) 

Mean velocity- 50 + 11 cm/sec 

Decrease color PRF to visualize low velocity 

Angle – anterior and superior

what is this an image of

“Butterfly

MCA-ACA bifurcation

Transtemporal Window – PCA

Depth

Flow direction

Mean velocity

Angle

whats the anatomic landmark

what is the size and shape

and what is the echogenicity?

Depth – 60 – 70 mm 

Flow direction – antegrade / toward 

Mean velocity – 39 + 10 

Angle – posterior and inferior 

Cerebral peduncles anatomic landmark 

Identical in size and shape 

Intermediate echogenicity

Suboccipital Window

evalutes what system

whats the technique of the patient postion and head

transducer is placed how and explain how its directed

Evaluates vertebrobasilar system 

Technique 

Patient lying on side 

Head bowed toward the chest 

Transducer placed on posterior aspect of neck 

Transducer slightly off midline- beam directed toward bridge of patient’s nose

Suboccipital Window  Image Orientation what are they and describe each one name 5

1. Foramen magnum- large circular anechoic area 

2. Occipital bone- bright echogenic reflection 

3. Right vertebral- left side of image 

4. Left vertebral- right side of image 

5. Basilar artery- deep to vertebrals

Suboccipital Window – Vertebral A

Depth

Flow direction

Mean velocity

Angle

Demonstrates a what shape configuration

Depth – 60 – 90 mm 

Flow direction – retrograde / away 

Mean velocity – 38 + 10 cm/sec 

Angle – right and left of midline 

Demonstrates a Y shape configuration

Suboccipital Window – Basilar A

Depth

Flow direction

Mean velocity

Angle

what would you do to your PRF and why

Depth – 80 – 120 mm  (deepest)

Flow direction – retrograde / away 

Mean velocity- 41 + 10 cm/sec 

Angle – midline 

Decrease PRF to visualize low flow velocities in verterbrobasilar system