Download mdct trauma protocol made efficient - SCBT-MR

MDCT TRAUMA PROTOCOL
MADE EFFICIENT:
TOTAL BODY SCANS
Ruedi
Ruedi F.-L.
F.-L. Thoeni,
Thoeni, M.
M. D.
D.
Department
Department of
of Radiology
Radiology and
and Biomedical
Biomedical Imaging
Imaging
University
University of
of California,
California, San
San Francisco
Francisco
Chief,
Chief, Abdominal
Abdominal Imaging,
Imaging, SFGH
SFGH
SCBT/MR, San Diego 2010
No DISCLOSURE
OBJECTIVES: MDCT FOR TRAUMA
• Describe full body trauma protocol with 64-slice
MDCT
• Demonstrate combining evaluation of visceral organs
with CTA including run off
• Outline use of MPRs and 3D volume rendering
• Display role for delayed imaging
• Outline radiation issues
Total Body MDCT Protocol in Trauma
Scans
Mode
Gantry Rot. Speed
64 x 0.625 mm
1: 0.984 or 1.375
0.5 sec
IV contrast 120-150 mL at 5 mL/sec saline flush 50 mL
Based on body scout
Head/neck
Reconstruction thickness
no iv
0.625 mm
Chest
IV, ~20 sec
1.25 mm
Abdomen/pelvis
IV, 80 sec
1.25 mm
Delay, abdomen/pelvis 3-5 min
Maybe cystogram to follow
1.25 mm
1.25 mm
Trauma Brain, Face, C
-spine
C-spine
PVA, resuscitated
Trauma Chest
Trauma Abdomen/Pelvis
?
24 yo shot in a nightclub
Supine delayed
Prone Cystogram
?
Bladder injury?
Total Body MDCT Protocol in Trauma
If plain films demonstrate fractures in pelvic ring or long bones
or penetrating trauma:
Body part
Delay Recon Thickness Noise Index
CTA of pelvis, ~ 23 sec
0.625 mm
long bones
bolus tracking
21
Chest
~30 sec
24
Abd/pelvis
80 sec
24
Delayed scans
3-5 min
27-29
(If CTA of neck needed, done before chest)
GSW Trauma Chest & LE
GSW to Chest & LE
Dose & Noise at Porta Hep. with Arms Down
Arm position
Noise*
Radiation dose∗∗
Arms up
15.8 +/- 2.8
1076 (614-1831)
One arm down
16.6 +/- 2.7
1312 (887-1805)
Two arms down
17.8 +/- 2.2*
1381 (973-1737)
Image quality decreased compared to standard but within
acceptable diagnostic limits
* P value for image noise: 0.002
** P value for radiation dose: 0.000
Brink M, de Lange F, Oostveen LJ, et al Arm raising at exposure-controlled multidetector trauma CT
of thoracoabdominal region: image quality, lower radiation dose. Radiology 2008; 249: 661-670
Multiplanar Reformations (MPR)
Better appreciation of complexity of findings
Increase efficiency
Effective tool for communicating with clinicians
•• Visceral
Visceral organ
organ injury
injury (coronal!)
(coronal!)
•• Bony
Bony fractures
fractures (spine,
(spine, pelvis)
pelvis)
•• CT
CT angiography
angiography
S/P Fall from roof
3 Dimensional (3D) Reformations
• Performed on separate workstation
• Generated within minutes by technologist
• Useful for preoperative planning of
complicated bony trauma
• Essential for CTA
Run off
Role of Delayed Imaging
• Maybe used selectively or routinely
• Obtained with an increased noise index
• Clarifies injuries to:
•• Kidneys
Kidneys and
and ureters
ureters
•• Solid
Solid organs:
organs: extravasation,
extravasation, pseudo
pseudo-aneurysm
aneurysm or
or arteriovenous
arteriovenous fistula
fistula
•• Mesenteric
Mesenteric injury
injury or
or other
other arterial
arterial injury
injury
•• Can
Can estimate
estimate size
size of
of bleed
bleed
Blunt Trauma to the Back (Fall)
PV phase 80 sec
Delay 33-5
-5 min.
Blunt Trauma due to high
-speed MVA
high-speed
PV phase 80 sec
Delay 33-5
-5 min.
PV phase 80 sec
Delay 33-5
-5 min.
Oral Contrast in Trauma
• Not routinely given in blunt abdominal trauma
• Delay in diagnosis
• Risk of aspiration (trauma board)
• Patient may have to go directly to the OR
• “Surgical” bowel adequately depicted
• Nearly static images of bowel with 64-slice
• Optimal bowel wall enhancement
• Positive oral contrast for penetrating trauma
GSW Wound to the Abdomen
Summary: Total Body CT Trauma Protocol
• Trauma head, chest and abdomen based on total body scout
• After head, do CTA when trauma to extremity or bony pelvis
• Reconstruct head & CTA at 0.625 mm, rest at 1.25 mm
• Thinner slices -> higher radiation
• Reducing radiation:
* Tube current modulation dose setting (Noise index)
- 21 for CTA
- 24 for chest/abdomen
- 27-29 for delayed imaging
* Sacrifice optimal visuals to sufficient diagnostic quality
* Arms up whenever possible!