1. Blunt Cerebrovascular Injury (BCVI): Spectrum of Imaging Findings
Joao Inacio, Ferco Berger, Daniel Hou, David Tso, Adrian Reagan, Savvas Nicolaou
Radiology Department, Emergency Trauma Section,
University of British Columbia /Vancouver General Hospital
Vancouver, BC, Canada
ASER, Seattle, 11-14th August 2010

2. Blunt Cerebrovascular Injuries (BCVI) [= Blunt Carotid/Vertebral Arterial Injury]
Objectives:
Scope of Blunt Cerebrovascular Arterial injury
Rationale for Screening
Screening Imaging Modalities
CTA Technical Aspects
BCVI: Spectrum of Imaging Findings
Conclusion

3. Introduction: BCVI includes:
Common and internal carotid arteries (71%)*
Vertebral arteries (29%)*
Both
BCVI is uncommon in the general blunt trauma setting but is more common than previously believed.
Incidence of % of all blunt trauma admissions**
Stroke prevention is a feasible goal of early diagnosis and treatment of BCVI
* Bub- Trauma: 2005
** Miller- Annals of Surg: 2003

4. Scope of the problem:
BCVI-related mortality rates of 23%, with 48%-80% of survivors suffering permanent severe neurological sequelae
The Denver group confirmed that many injuries are clinically occult at admission
The majority of injuries diagnosed after CNS ischemic symptoms, hours to days after the traumatic insult

5. Blunt Cerebrovascular Injuries (BCVI)
Objectives:
Scope of Blunt Cerebrovascular Arterial injury
Rationale for Screening
Screening Imaging Modalities
CTA technical aspects
BCVI: Spectrum of Imaging Findings

6. Rationale for Screening :
Patients at risk for BCVI can be identified and diagnosed before the onset of symptoms with the application of an appropriate screening modality
Institution of medical therapy or revascularization has significant impact on prognosis
Screening BCVI : exceeds 1% of blunt trauma admissions
Incidence up to 2.7% in patients with Injury Severity Score ≥16

7. BCVI and Stroke: Majority occur 10 – 72 hours post trauma
Effective screening criteria remain elusive
Blunt Carotid injury: Mortality % Neurological Sequelae - 58%
Blunt Vertebral Artery Injury: Mortality - 8% Neurological Sequelae - 24%

8. BCVI and Stroke:
Screening for BCVI: Identification of asymptomatic patients with BCVI and prevent neurological complications.

9. Criteria for screening/ Risk Factors Denver Modified BCVI Screening Criteria
Clinical Signs/Symptoms of BCVI
Risk factors for BCVI (High-energy transfer mechanism)
Blunt Cerebrovascular Injury Practice Management Guidelines, J Trauma. 2010

10. Criteria for screening/ Risk Factors Denver Modified BCVI Screening Criteria (I)
Signs/symptoms of BCVI:
Arterial hemorrhage
Cervical bruit
Expanding cervical hematoma
Focal neurological deficit
Neurologic examination unexplained by neuroimaging findings
Ischemic stroke on secondary Head CT
Blunt Cerebrovascular Injury Practice Management Guidelines, J Trauma. 2010

11. Criteria for screening/ Risk Factors
Criteria for screening/ Risk Factors Denver Modified BCVI Screening Criteria (II)
Risk factors for BCVI:
Lefort II or III fractures
Cervical spine fracture patterns:
Subluxation
Fractures extending into the transverse foramen
Fractures of C1–C3
Basilar skull fracture with carotid canal involvement
Diffuse axonal injury with Glasgow Coma Scale score <6
Seatbelt contusion on neck (not isolated)
Near hanging with anoxic brain injury
Blunt Cerebrovascular Injury Practice Management Guidelines, J Trauma. 2010

12. Denver Modified BCVI Screening Criteria: Limitations
20-27% patients with BCVI may not fulfill the commonly reported screening criteria
Other liberal screening criteria:
Thoracic Abbreviated Injury score of ≥3
Injury Severity Score ≥16
Skull/ C-spine Fracture line extending to vascular channel

13. Vancouver General Hospital Screening Criteria
Any blunt trauma patient with GCS ≤ 13
Any trauma patient with GCS > 13 plus:
Cervical spine injury
Basal Skull fracture
Diffuse Axonal injury
LeForte II/III fracture
Significant thoracic injury
Abnormal neurological exam not explained by CT scan of the head
Discretion of attending Trauma Surgeon

14. Objectives:
Scope of Blunt Carotid/Vertebral Arterial injury
Rational for Screening
Screening Imaging Modalities
CTA technical aspects
BCVI: Spectrum of Imaging Findings

15. Screening Imaging Modalities
What is the appropriate modality for the screening and diagnosis of BCVI?
Diagnostic digital subtraction (DSA) four-vessel cerebral angiography: remains the gold standard modality.
MDCT is the best non invasive screening modality in place of DSA.
MRI Angiography is promising but with limited availability.
Duplex ultrasound is not adequate for screening for BCVI.
Blunt Cerebrovascular Injury Practice Management Guidelines, J Trauma. 2010

16. BCVI Screeninng: MDCT vs DSA Controversy and Consensus
Strokes are prevented by early diagnosis and antithrombotic therapy.
The harder you look for BCVI, the more injuries you will find
Does CTA false-positive/ negative studies reflect the technology or the interpretation?
≥16-slice MDCT CTA is the most accurate noninvasive screening modality available
More data needed to know if and when to submit patients to confirmatory DSA, with its attendant risks and expense.
Biffl, Walter L., (editorial) J Trauma February 2010

17. Objectives:
Scope of Blunt Carotid/Vertebral Arterial injury
Rational for Screening
Screening Imaging Modalities
CTA technical aspects
BCVI: Spectrum of Imaging Findings

18. CT Trauma Evaluation Technical Aspects
STANDARD (Segmented) MDCT PROTOCOL:
Scout head and C-spine
Nc Head CT
C-spine or CTA vertex to arch
- Arms Reposition-
CTA Chest + Abd (arterial)
CT Abd + Pelvis (venous)
- 5’ delay-
CT Delayed excretory phase and
Focused CT:
Peripheral vascular injuries
Complex limb fractures
1st bolus IV contrast
2nd bolus IV contrast
3rd bolus IV contrast

19. VGH Blunt Neck Trauma CTA Protocol: Part of Segmented Trauma Series CT
Arterial phase Arch to COW
mAs(Tube A) kV 120
500
Kernel B
B46(Mediastinum) 2 x1mm
MIP recon thru COW and Carotids
B75(Bone) 2x 1mm for C Spine
Collimation
128 mmx 0.6mm
Pitch
1.1
Rotation Time s
CTDIvol 25
Note: Bolus tracking at arch using 120 cc of 320 mgI/mL at 5.0mL/s for arterial phase acquisition.

20. CT Trauma Evaluation Technical Aspects
WHOLE BODY (CONTINOUS) MDCT PROTOCOL:
Scout head to toe or NO SCOUT
Nc Head CT (1st scan)
CTA vertex to pelvis (arterial) (2nd scan)
CT Abd + Pelvis (venous) (3rd scan)
Pros:
Faster acquisition
Less radiation
Less iodine contrast
1st bolus IV contrast
Cons:
Artifacts from arms position
Lower signal to noise ratio
Demanding post processing

21. CTA Arch to vertex: Technical Aspects
POST-PROCESSING:
Multiplanar reformation is applied for precise quantitative analysis of lumen and vessel wall
Routine reformatted series:
Axial source images 2mm
MPRs 2mm:
Cervical Coronal
Oblique sagital of carotid bifurcations
MIPs 3mm:
Head and neck: axial
Cervical: carotid bifurcations
Head: coronal, sagital                   
Sagital Head to COW bone images 2mm

22. Objectives:
Scope of Blunt Carotid/Vertebral Arterial injury
Rational for Screening
Screening Imaging Modalities
CTA technical aspects
BCVI: Spectrum of Imaging Findings

23. BCVI: Spectrum of Imaging Findings
Denver Grading Scale:
Grade I – Minimal Intimal injury / intimal irregularity with <25% narrowing
Grade II - Dissection with raised intimal flap; intramural hematoma with >25% narrowing; Intraluminal thrombus
Grade III - Pseudoaneurysm
Grade IV - Occlusion/ Thrombosis.
Grade V - Transection with free extravasation
Arteriovenous fistula: ± Hemodynamic significance (Grade II or V)
Blunt carotid arterial injuries: implications of a new grading scale, Biffl et al. J Trauma 1999

24. Grade Injury and Prognosis
Denver Grading Scale:
Stroke incidence in Blunt Carotid Injury:
Grade I - 3%
Grade II - 11%
Grade III – 33%
Grade IV - 44%
Grade V – 100%
Blunt carotid arterial injuries: implications of a new grading scale, Biffl et al. J Trauma 1999

25. Grade Injury and Prognosis
Denver Grading Scale:
Stroke incidence in Blunt Vertebral Artery Injury:
Grade I – 19%
Grade II - 40%
Grade III – 33%
Grade IV - 13%
Grade V – 0 cases
Biffl WL, et al, Blunt carotid and vertebral arterial injuries. World J Surg 2001

26. BCVI: Spectrum of Imaging Findings
Major segments involved:
Distal Cervical segments of ICA
Petrous and Cavernous ICA
Vertebral arteries C1-C2 and C6
18-36% Multiple Arteries Are Injured

27. Left Internal Carotid Minimal Intimal Injury (Grade I)
Figure 1. Left Internal Carotid Minimal Intimal Injury. 39y Male, MVC. Sagital Cervical MPR. MRI axial T1 image. Left Internal Carotid Minimal Intimal Injury with high intensity Intramural hematoma, <25% luminal narrowing.

28. Right Vertebral Minimal Intimal Injury (Grade I)
Figure 2. Right Vertebral Artery multofocal Minimal Intimal Injury.

29. Left Internal Carotid Dissection (GRADE II)
Figure3. 40y Male, MVC. Sagital Cervical MPR and axial source image. Left Internal Carotid Artery dissection with raised intimal flap.

30. Vertebral Artery Dissection (GRADE II)
Figure y female, MVC . Whole body CT trauma protocol with coronal cervical MPR and posterior fossa axial image. Left vertebral artery dissection with raised intimal flap, and left cerebellar ischemic infarct. DSA correlation with long vertebral artery dissection from C2 to C6.

31. Right Internal Carotid Dissection/Intramural Hematoma >25% Luminal Stenosis/Pseudoaneurysm (GRADE II AND III)
Figure 5. Grade II Injury. Snowboarding injury with 15 minutes loss of consciousness at the scene. CTA with oblique sagittal and coronal MIP reformats with bilateral wall hematoma resulting in >25% stenosis, with extension to the petrous segment on the right. There is also a pseudoaneurysm in keeping with a grade III injury.

32. Right Internal Carotid Pseudoaneurysm (GRADE III)
Figure 6. Grade III Injury. Distal Right Internal Carotid Pseudoaneurysm. CTA coronal, sagital , axial images with DSA correlation.

33. Bilateral Occlusion of Vertebral Arteries (Grade IV)
Figure 7. Grade IV Injury. Bilateral Occlusion of the Vertebral Arteries. MVA with seat belt sign neck, > 50% subluxation of C5/C6 with locking facets: two associated risk factors for BCVI.

34. Unilateral Occlusion of Vertebral Artery (Grade IV)
Figure 8. Grade IV Injury. 30 y male, MVC . RIPIT protocol with coronal neck MPR and posterior fossa axial image. Left vertebral artery traumatic thrombosis and left cerebellar infarct.

35. Left Vertebral Artery Transection with active contrast extravasation (Grade V)
Figure 9. Grade V Injury. 35 y Male, MVC ; Whole body CT trauma protocol with cervical VR. Atlantoaxial dissociation, left vertebral artery transection with active contrast extravasation.

36. Left Vertebral Artery Transection with active contrast extravasation (Grade V)
Figure 10. Grade V Injury. Left Vertebral Artery transection with active contrast extravasation.

37. Follow-up imaging:
Both untreated and medically treated injuries can either heal or progress
Standardized follow-up regimens are mandatory
≥7-10d post trauma

38. Western Trauma Association Critical Decisions in Trauma:
Screening for and Treatment of Blunt Cerebrovascular Injuries. Biffl, Walter et all, J Trauma December 2009. 2

39. Conclusion
Diagnostic Imaging plays a vital role in diagnosis of cerebrovascular injuries
Prompt diagnosis and treatment impacts prognosis
DSA is the gold standard for BCVI screening
CTA as proved especially valuable
CTA technical aspects and Interpretation must be considered in management decisions
Screening and treatment of BCVI is effective

40. References End Biffl, Walter et all, J Trauma December 2009
Biffl WL, Ray CE, Moore EE, et al. Ann Surg 2002
Miller PR, Fabian TC, Bee TK, et al. J Trauma 2001
Biffl et al. J Trauma 1999
Silker et al. AJR 2008
McKevitt et al. Am J Surg 2002
Sliker. Radiographics 2008
Sliker CW, Shanmuganathan K, Mirvis SE. AJR 2008
Goodwin, Robert et al., J Trauma, 2009
Josser E. Delgado Almandoz, Radiology 2010
End