Download Whole body MDCT in trauma-Detection of vascular injuries

P. Mehta, S. S. Hedgire, T. Kalyanpur,
K. S. Narsinghpura, V. Kasi, M. P. Cherian
KOVAI MEDICAL CENTER & HOSPITAL,
COIMBATORE
INDIA
Evolution of CT
X-ray tube
First generation ct-1973
Multislice spiral ct-1998
Dual source ct-2005
Single detector
Multiple detectors
MDCT
Increase in number of slices by
1. Increasing number of rows of
detectors
2. Periodic motion of focal
spot in Z axis (flying focal
spot)
MDCT - Not only speed but also clarity
Whole body MDCT and trauma
• Timely localisation of active bleeding sources.
•determining the presence and extent of other organ
injuries
•serves as a baseline for monitoring of conservative
treatment.
•Replaced conventional angiography and plain film
radiography in most trauma centers.
Whole body MDCT-protocol
 Plain CT – Head.
CECT
1. Arterial phase: From circle
of willis through symphysis
pubis.
2. Venous phase: From
base of lungs through
symphysis pubis.
Axial images
IMAGE ANALYSIS
3D display
2D/MPR
Maximum intensity projection.
Volume rendering technique
Shaded Surface Display
Endoluminal Virtual Angioscopy
Timely detection of vascular injury can
be life saving
Vascular injuries
Arterial injuries
•Active arterial hemorrhage
•Occlusion
•Dissection
•Pseudoaneurysm
•Transection
Vascular Injuries
 Other arterial injuries:
Arteriovenous fistula
Intimal injury
Spasm
 Venous injuries:
Active venous hemorrhage
Contour irregularity
Venous thrombosis.
Role of dual phase
PSEUDOANEURYSM
& AV FISTUALA
EXTRAVASATION
DIFFERENTIATE
Attenuation more
than the aorta in
venous phase
Attenuation similar
to aorta in venous
phase
Interpretation of vascular injury
•Site and type of injury
•Extent of injury
•Diameter of vessel
proximal and distal to
injury
•Percent of vascular
narrowing
•Integrity of distal tissue
•Proximity to other vessels.
•Abormal anatomy of vessel.
Acute Traumatic Aortic injury(ATAI)
 Serious outcome in trauma.
 95% morbidity and mortality if untreated.
 MDCT -investigation of choice.
 Thoracic aortic injuries - 20 times more
common than abdominal aortic injuries.
Common signs
*Aortic pseudoaneurysm
*Periaortic hemorrhage
*Displacement of
esophagus and trachea,
irregular aortic contour
*Dissection/intimal flap
Uncommon signs
*luminal clot at site of
intimal injury
*sudden change in
aortic caliber or small
aortic caliber in lower
chest and abdomen,
*peridiaphragmatic
hemorrhage
Complete aortic rupture
 Extremely rare.
 Commonest site: Aortic isthmus.
Complete aortic rupture
 Classical sign: active
extravasation of contrast
from aorta with adjacent
hematoma
Steenburg S D et al. Radiology 2008;248:748-762
Aortic Pseudoaneurysm

Secondary to disruption of inner layers / entire
vessel, with blood contained by adventitia or
perivascular soft tissues.
Aortic psudoaneurysm
 Well circumscribed,
lobulated, focal
outpouching of contrast
enhanced blood that
communicates with
aorta.
Kaewlai R et al. Radiographics 2008;28:1555-1570
Complications
of pseudoaneurysm
1.Rupture and hemorrhage
2.Thrombosis and distal emboli.
Aortic dissection
INTIMAL
FLAP
 Pathognomonic sign:
Identification of
intimal flab.
 False lumen:
a.Decreased density of
contrast.
b.Larger in caliber
c.Acute angle with outer
wall
Hayter R G et al. Radiology 2006;238:841-852
MDCT demonstrates
Integrity of
distal organs
Extension into major
branches
Extent of
dissection
Acute intramural hematoma(AIH)
 Synonym : Non communicating aortic
dissection.
 Progression:
a. Rupture of aortic wall externally.
b. Rupture internally - communicating
aortic dissection
 Differential diagnosis: Mural thrombus
Acute intramural hematoma
 Hyperdense on plain CT.
 Hypodense on CECT.
www.radswiki.net/main/images/Intramural Hematoma
Imaging pitfalls
 Technical:
Patient motion.
Cardiac pulsation/Breathing.
Streak artifacts.
Poor contrast enhancement.
 Anatomical
Vein:
Artery:
Left superior intercostal vein, hemi azygos
vein simulate dissection when abutting the
aorta.
Infundibulum at the origin of bronchial and
intercostal arteries.
Atypical ductus bump
Normal post isthmic aortic dilatation.
Imaging pitfalls
 Atypical ductus bump
 Ductus remnant
Hemoperitoneum
Its presence warrants
careful evaluation.
Hemoperitoneum :
Unclotted blood: 30-45HU
Clotted blood: 45-70 HU.
Active arterial
extravastion: 85-370 HU.
Mesenteric Injuries
 Mesenteric hemorrhage flows into interloop space.
Specific findings
Active extravasation
Vascular beading
Abrupt termination
of vessel
Mesenteric Injuries
NON SPECIFIC
FINDINGS
1.Mesenteric hematoma
2.Fat stranding
3.Abnormal thickening and
enhancement of bowel
Solid abdominal visceral trauma
Liver
 Management changed
towards non surgical
management based on
CT input
 MDCT - further pushing
it towards Endovascular
management
Active bleed
Spleen
SpleenSpleen-Active
pseudoaneurysm
bleed
Arterial phase
Delayed phase –
Wash out of contrast
Pitfalls in MDCT
 Technical factors:
1. Poor bolus timing
2. Early scanning in venous phase-pseudothrombus .
3. Single phase acquisition – venous injuries missed.
4. High resolution kernel reconstruction – optimal for
evaluation of bone not for vessel.
5. Retained extravasated contrast material
mimic active bleeding in follow-up CT.
Pitfalls in MDCT
 Patient factors:
1. Motion artifatcs.
2. Beam hardening artifacts
from metals/IV contrast – create
pseudolesions /hide subtle lesion
Beam hardening
artifact
Multi-slice CT and Interventional
Radiology
An ideal combination in
life threatening vascular
injuries associated with
Trauma
Role of MDCT in interventional
radiology.
 As a road map to targeted angiography of bleeding
vessel and embolisation.
 For planning the procedure in case of stent grafts.
 Post procedural follow up to look for patency of stent
and stent graft leak.
Therapeutic options in polytrauma
 A.Embolisation
a.CECT:Pseudoaneurysm
from gastro duodenal
aretery.
b.Preembolisation DSA pseudoaneurysm from
gastroduodenal aretry.
c.Postembolisation DSA:
Complete occlusion of
pseudoaneurysm.
Therapeutic options in polytrauma
 B. Stent grafts
a.CECT: Aortic rupture
with mediastinal
hematoma
b.DSA and Stent grafting.
c. Follow up CT: No active
extravastion of contrast
from aorta.
Conclusion
Whole body MDCT- the modality
of choice in evaluation of traumatic
vascular injuries.