Transcript CT_training_whi_final

WHI Coronary Artery
Calcium Study
(WHI-CACS)
CT Scan Site Training
Presentation
J. Jeffrey Carr, MD, MSCE
May 2005
Wake Forest University Health Sciences
Winston-Salem, NC
Objectives
• Learn about the study.
• Learn and understand the CT scanning
protocol.
• Opportunity ask/submit questions to the
CTRC at Wake Forest!!!!
• This presentation supplements the detailed
material located in the 3-ring binder at each
CT scan site.
What is WHI-CACS?
• Women’s Health Initiative (WHI) Coronary Artery
Calcium Study (full abbrev. = WHI-CACS)
• Is a sub-study of the WHI involving women who
received either Estrogen or placebo to better
understand the role of hormone replacement.
• The objective is to measure coronary atherosclerosis
by CT and compare those who received estrogen to
those who received placebo.
• In WHI-CACS we will measure Coronary Artery
Calcified Plaque (CACp) using a CT scanner with
cardiac gating capability.
WHI-CACS CT exam
Slide 3
Wake Forest U. Health Sciences - CTRC
How is the study organized?
• ~30 WHI Clinical Centers will recruit and CT
scan participants.
• CT Reading Center
• Wake Forest U. Health Sciences
Winston-Salem, NC will receive and measure the
CT scans for Coronary Artery Calcified Plaque
• Data Coordinating Center
• Fred Hutchinson Cancer Research Center will
perform analysis.
WHI-CACS CT exam
Slide 4
Wake Forest U. Health Sciences - CTRC
WHI Coordinating
Center
CT Reading Center will
send the results to the
data coordinating center
Seattle, WA
CT exams will be sent to
WFU via FEDEX on CD
WFU
CT Reading
Center
Site 1 CT
Site 2 CT
CT exams scanned at the ~30
Field Centers, ~ 900 total exams
Site 24 CT
Site 25
CT
Let’s Learn the CT Protocol!
• CT scanning protocol
• Sending the images to Wake Forest
• Quality Control (QC) procedures /
Phantom CT scans
CT Visit - Overview
• Greeting participant
• Make sure they are the “correct” person
• Female
• Here for “WHI-CACS CT Scan”
• Prepare participant by indicating there will be
several times they are asked to hold their breath
• Scout / topogram /scanogram images
• Watch how they do – provide further instructions
• Heart scan w/ECG
• Help participant exit CT scan suite
Participant Preparation
• Instruction prior to scan (clinic staff)
• No caffeine products before scan (3 hrs)
• Have loose clothing to facilitate placing ECG
leads
• No metal/jewelry around chest - this includes
under-wire bras which will need to be removed or
repositioned
• Have clinic fax / deliver participant CT completion
forms prior to study.
Entering Participant Information
Into the CT Scanner
• Maintain confidentiality
• Positively identify each person
• Identifiers have been assigned by the
coordinating center – two codes are
used:
• Study ID number (SID)
• Name code
CT data entry WHI-CACS
Name:
ID number:
Date of Birth:
Technologist:
Indication:
BCABCDEL
1201234L
03 MAR 1947
51 (initials or ID)
WHI-CACS
WHI-CACS CT exam
Slide 10
Wake Forest U. Health Sciences - CTRC
How do you know what to type in
to the CT scanner?
• Each participant is consented & screened by
the clinic prior to the CT exam
• Consent form is sign ahead of time
• The participant is scheduled for the CT exam
• You will be sent a WHI-CACS CT
Worksheet which will have the needed
information.
WHI-CACS CT exam
Slide 11
Wake Forest U. Health Sciences - CTRC
Participant CT Worksheet
<<participant DOB>>
DOB
Replace “real
name”
Study ID
WHI-CACS CT exam
Slide 12
Wake Forest U. Health Sciences - CTRC
CT Worksheet
Tech ID
Let us
know any
problems!
Fax back
to WHI
Clinic
WHI-CACS CT exam
Slide 13
Wake Forest U. Health Sciences - CTRC
CT Scanning overview
• Scouts - Thoracic
• Frontal
• Lateral (optional)
• Heart w/ ECG gating
• Late Diastole:
•
•
•
•
EBCT 80%
GE MDCT 70%
Siemens 50%
Others TBD
• We will provide a detailed protocol sheet for
each specific CT scanner.
Breathing Instructions
“Take a deep breath in <pause>
Blow it all the way out <pause>
Take a deep breath in <pause>
Blow it all the way out <pause>
Take a deep breath in and hold it.
******Scan 20-40 seconds*****
Breathe and relax”
The Breathing Instructions are
very Important!
• Do the same instructions for scout and heart
scans.
• Why deep breath in?
• Pushes liver down,
• Valsalva lowers heart rate,
• Blowing off C02 (hyperventilation) makes it easier
to hold breath!
• Use custom pre-recorded voice if available.
• Have participant do the best they can –
breathe out slowly if they cannot hold the
entire time.
ECG – Lead placement
• Arms overhead
• Reposition leads if necessary
• Make sure amplitude (i.e. size) is OK per your CT
scanner instructions
ECG positioning
• Manufacturer or local recommendations
• “White is Right –
Smoke (black) over Fire (red) (left side)
• Must have identifiable R-wave, if not
reposition & check connections
• Prospective triggering/gating - late diastole
phase
•
•
•
•
EBCT @ 80% (636-736)
Siemens at 50%-TBD, (428, 755)
GE at 70% ( 437-763)
Phillips/Toshiba - TBD
Check Thorax Scouts for:
• Participant centered?
• Prescribe cardiac scan
• Carina thru inferior aspect of the heart
• Lateral scout may be useful to prescribe AP
centering of reconstructions
• Scan using a 27 cm FOV !!!!!!!! Which should
be centered on the heart - if you clip any of
the heart reconstruct adjusting offsets as
appropriate.
Scouts –
Landmarks for Prescribing Scans
Start
Start
End
End
Cardiac Scan
•
•
•
•
Check coverage
Check centering
Check ECG
Confirm correct technique (KV, mAs,
slice thickness 3 mm or 2.5 mm)
• Make sure participant holds breath
according to protocol
Archive & Make a CD for us
• Archive the exam locally - this is to
cover the possibility that some how the
data is lost during the transfer
• Burn the entire exam (or multiple
exams) to a CD
• Label the CD and place in FedEx
envelope.
WHI-CACS CT exam
Slide 22
Wake Forest U. Health Sciences - CTRC
Sending CT scans to the Wake
Forest CT Reading Center
• Scans will be transferred to the CT reading
via FedEx
• We will provide you address labels so you can charge
the costs to us
• If possible send a weeks worth of scans at
one time. If however no additional WHI scans
are scheduled go ahead and send the CD.
• Contact us with your questions
• Chris O’Rourke
• [email protected] 336 716 8909
• Main: 336.716.7234
Scales Require Calibration So do CT Scanners!
QuickTi me™ and a
T IFF (Uncompressed) decompressor
are needed to see thi s pi cture.
•We all know that you can “adjust” the zero value of a scale to
weight “heavy” or preferably “light”
• CT Scanners can have the CT number value of water (0 H.U.)
adjusted to be “brighter” or “darker”
WHI-CACS CT exam
Slide 24
Wake Forest U. Health Sciences - CTRC
Why are we scanning the
Torso & QCT phantoms?
• To make sure your CT scanner’s ability
to measure CT numbers (HU) is correct
• To better understand any potential
differences between CT systems at the
different sites
QC Scan Procedure –
What Will I have to Do?
• CT Reading Center will FedEx the phantoms to your
site, including instructions *** Save the Box ***
• Follow the instructions - The idea is to scan both
phantoms with the same technical factors as we plan
for the WHI participants
• Call us if you have any questions - the QC scans
should take less than 15 minutes to set-up and
complete
• Burn the exam to CD and FedEx the CD to us at
Wake Forest
• Re-Package the Phantoms and send to the next WHI
site as instructed.
QCT Phantom – Parts
Setup for Quality Control scans
Torso phantom (oval)
Center
torso
plug
QCT Calibration phantom
(rectangle)
4 tubes containing:
0, 50, 100 & 200 mg/cc Calcium
Cardiac Phantom Setup
This should be
at isocenter
using your laser
alignment
system
Thank You!
We are here to help!
Please Complete your
Pre-Certification Form Now
• Call or Fax us with your questions!
• Voice: 336.716.7234
• Fax: 336.716.4340