SGEM#91: CT Angiography for Blunt Cerebrovascular Injury Detection in Trauma Patients

Podcast Link: SGEM91
Date:  September 30th, 2014 

Guest Skeptics: Dr. Marcel Emond. Associate professor, Laval University.  Emergency physician the level one trauma centre in Quebec City. Research Director of the Canadian Emergency Team Initiative (CETI).

Case: 21 yo man looses control of his snowmobile and presents to a small rural hospital with a head and neck. His vital signs are stable. Glasgow Coma Scale=7. He is moving all extremities. There is a C3/4 fracture identified on xray. He is intubated at the rural hospital and transferred to you at the trauma centre.

Questions: Is CT angiography accurate for detecting blunt cerebrovascular injury?

Article Roberts et al. Diagnostic accuracy of computed tomography angiography for blunt cerebrovascular injury detection in trauma patients: A systematic review and meta-analysis, Ann Surg 2013; 257 (4): 621-32.

  • Population: Systematic review of 8 studies enrolling patients >16 years after sustaining blunt trauma with suspected blunt cerebrovascular injury (BCVI) based on risk factors or clinical signs. N=1426 patients presenting to United States trauma centres.
  • Intervention: CT angiography (CTA) of carotid and vertebral arteries

  • Comparison: Digital subtraction angiography (DSA) of carotid and vertebral arteries
  • Outcome: Summary diagnostic accuracy of CTA compared to DSA for blunt cerebrovascular injury.

Authors Conclusions: Existing evidence suggests that the diagnostic performance of CTA varies considerably across studies, likely due to an implicit variation in diagnostic threshold across trauma centers. Moreover, although CTA appears to lack sensitivity to adequately rule out BCVI, it may be useful to rule in BCVI among trauma patients with a high pretest probability of injury.

checklist-cartoonQuality Checklist for Systematic Review:

  1. The diagnostic question is clinically relevant with an established criterion standard. Yes
 Comment: Though invasive and labour intensive, digital subtraction angiography is currently the criterion standard for detection of cerebrovascular injury.
  2. The search for studies was detailed and exhaustive. Yes
  3. The methodological quality of primary studies were assessed for common forms of diagnostic research bias. Yes
  4. The assessments of studies were reproducible. Yes
  5. There was low heterogeneity for estimates of sensitivity or specificity. No
  6. The summary diagnostic accuracy is sufficiently precise to improve upon existing clinical decision making models. No 

Key Results: Eight studies with a total 5704 carotid or vertebral arteries in 1426 trauma patients were included. Pool results for blunt cerebrovascular injury detection with CTA vs. digital subtraction angiography

  • Sensitivity 66% (95% CI 49-79%)  I2 =80 (lots of heterogeneity)
  • Specificity was 97% (95% CI 91-99%) I2=94
  • +LR was 20 (95% CI 6.9-58.4) I2=88
  • -LR was 0.35 (95% CI 0.22-0.56) I2=75

Commentary: This was a well-performed SR/MA. However, most of the studies included had unclear blinding. There was also a problem with heterogeneity was in all the measures between studies. Sources of heterogeneity might include who was reading the CTA, CT modality (16 or fewer slices), or diagnostic threshold variability between studies.

IMG_2524This study discussed likelihood ratios for diagnostic value of the test. If you have a LR of 1 it means no effect. However, if you have a +LR of >10 it is highly diagnositic for ruling in the condition. If you have a –LR of <0.1 it is highly diagnostic of ruling out the condition.

This review shows diagnostic accuracy of CTA for blunt cerebrovascular injury varies across institutions. While the pooled -LR was inadequate to rule-out blunt cerebrovascular injury at 0.35. This is greater than the <0.10 to feel confident about ruling out a condition.

On the other hand, the +LR of 20 warrants consideration in ruling in the injury for those with high pre-test probability. Further study with a standard diagnostic threshold is required.

If ultimately deemed to be specific enough, CTA will allow testing for an easily missed but devastating injury without resorting to a cumbersome and time- consuming procedure. However, this review will not be the last word on the matter.

Dr. Marcel Emond

Dr. Marcel Emond

Comment on authors conclusion compared to our conclusion: We agree there is significant variability in the sensitivity of CTA for blunt cerebrovascular injury across institutions, a conclusion that, on its own, warrants further study to confirm why this is the case.

Bottom Line: Blunt cerebrovascular injury is an uncommon but dangerous injury to miss. Unfortunately, the current best test to confirm the problem remains one that is onerous to perform and not as widely available as CT.

Case Resolution: You have a high pre-test probability this man has a blunt cerebrovascular injury. You get a CT angiography which is negative.  A digital subtraction angiography is performed and demonstrates a blunt cerebrovascular injury. He is sent to the appropriate referral service to address this rare but critical injury.

Clinical Application A negative CTA in a patient with high suspicion for blunt cerebrovascular injury warrants further work up with digital subtraction angiography.

What do I tell my patient We are uncertain whether a CT scan of the blood vessels in your head and neck will confidently exclude significant injuryies. For the time being, if you’ve suffered a serious head or neck injury, it’s better to be at a trauma centre with an interventional radiologist who can perform the more invasive and time-consuming test to exclude these injuries. However, if an interventional radiologist is unavailable and a CT angiogram demonstrates a significant injury, we will consult the surgeons immediately.


Dr. Samuel Ritter von Basch

Keener Kontest: Winner last week was Dr. Ellie Wallance an Emergency Medicine resident at Boston Medical Center, in Boston, MA. She knew The sphygmomanometer was invented by Samuel Ritter von Basch in 1881.

Listen to the podcast to hear this weeks keener question. If you know the answer send an email to with “keener” in the subject line. The first person to correctly answer the question will receive a cool skeptical prize.

Upcoming conferences: SkiBEEM 2015 is January 26th-28th in Beautiful Sun Peaks, BC.

Remember to be skeptical of anything you learn,

even if you heard it on the Skeptics’ Guide to Emergency Medicine.

Q&A with a Virologist: Ebola in the ED at St.Emlyn’s

St Emlyns - Meducation in Virchester #FOAMed

This week Sarah Payne from the North East of England joins St.Emlyn’s. Sarah is no stranger to blogging and is a keen #FOAMed advocate as her bio below clearly shows. Specialty trainee in Emergency Medicine in the Northern region, currently out of program as a Simulation Teaching Fellow across the Newcastle Hospitals trust and Associate […]

The post Q&A with a Virologist: Ebola in the ED at St.Emlyn’s appeared first on St Emlyns.

I am Dr. Ryan Radecki, author of EM Literature of Note: How I Work Smarter

How I Work Smarter LogoIn a previous How I Work Smarter post by Dr. Ken Milne, he called out Dr. Ryan Radecki, who is the outspoken and prolific author of EM Literature of Note and a premiere mythbuster in EM, specifically around thrombolytics in stroke. For those of us in the blogging world, not everyone knows that he lives a dual academic life working on medical informatics and information design. He is, in fact, funded through an NIH grant from the Agency of Healthcare Research and Quality for a training program in patient safety. Ryan shares his tips for working smarter.

  • radecki_headshotName: Ryan Radecki, MD, MS
  • Location: Houston, TX
  • Current job: Assistant Professor of Emergency Medicine at The University of Texas Medical School at Houston
  • One word that best describes how you work: Everywhere
  • Current mobile device: iPhone 5
  • Current computer: 15” Macbook Pro

What’s your office workspace setup like?

What’s an office? I’m lucky enough to have such flexibility in my position I’m confined only to wherever my creative needs take me on the day. I’ve got a quiet space set aside at my home as a “home office”, which is where podcasting and administrative work gets done. But my main office – is every coffeehouse in town, depending on the rest of the day’s logistics. Today, I’m at Boomtown Coffee – fueled by iced toddy mocha.

Radecki home office

Radecki Coffee Shop


What’s your best time-saving tip in the office or home?

There are few time-wasting endeavors I dislike more than time spent commuting. I have always specifically tried to live in locations with the shortest possible commute. I also ride my bike to work, when possible – I arrive far more awake, and with the added bonus of having accomplished part of my exercise for the day.

What’s your best time-saving tip regarding email management?

Run e-mail like running the department – disposition-focused. Delete as much as possible, respond immediately by phone when practical, and otherwise “run the list” of recent e-mails a couple times a day when the opportunity arises.

What’s your best time-saving tip in the ED?

Document as much as possible up front, immediately after the patient encounter. I don’t document during the encounter. I’d rather have an effective, efficient patient encounter and charting session in series, rather than do both tasks simultaneously, but poorly. Then, left to the end of shift, documentation quality both degrades and requires longer to create.

ED charting: Macros or no macros?

Macros. Ideally, lots of macros – focused on the most common complaints and recurrent medical decision-making documentation.

What’s the best advice you’ve ever received about work, life, or being efficient?

Everyone mentions the ability to say “no” as critical – and I agree. While there’s always some modicum of suffering required, the fewer extraneous responsibilities outside your areas of passion, the better. More time available to do your best work? Win.

Is there anything else you’d like to add that might be interesting to readers?

I strongly feel it is our ethical responsibility to patients and society at large to order precisely the indicated tests and therapies – no more, no less. Being judicious with limited resources is an incredibly difficult challenge – but the alternative is simply lazy, thoughtless, wasteful medicine. I also find involving patients in decisions at every step of the process, with explanations of goals of care, diagnostic strategies, and estimates of costs – results in interesting and revealing conversations of substantial value in directing care. Many patients opt for less complex diagnostic evaluation, and more focus on symptom resolution – and thus my rates of use of advanced imaging and hospitalization are much lower than average, without apparent degradation in safety at discharge. This is, in many ways, the future of medicine – as the writing is already on the wall regarding cultural shifts to decreasing unnecessary testing and resource utilization.

Who would you love for us to track down to answer these same questions?

  • Megan Ranney
  • Nick Genes
  • Jeremiah Schuur

Author information

Michelle Lin, MD

ALiEM Editor-in-Chief

Editorial Board Member, Annals of Emergency Medicine

UCSF Academy Endowed Chair for EM Education

UCSF Associate Professor of Emergency Medicine

San Francisco General Hospital

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Subtle signs of ischaemia that need cath lab NOW…

Dr Steve Smith is not just a great educator and blogger, he is probably the foremost person you wish you could see when you are having chest pain. This talk is essential for anyone who reads ECGs for a living and treats chest pain. Kudos to the SMACC team for releasing this vid to one of the best lectures of the conference.

Steve Smith Subtle ECG Signs of Ischemia from Social Media and Critical Care on Vimeo.

The slides are here:

Web Resources about Palliative Care, by Diego Ruiz

Hola a  tod@s and happy Sunday.

From IC-HU Project we want to thank all the people that have collaborated in this week of  #CuidadosPaliativosIntensivos with your post, reviews and spreading the message.

We really hope that could be possible those daily and quality palliative care, with appropiate human and technical resources and could reach all those person who need them. 

Thanks especially to Dr. Diego Ruiz  López.  As well as writing and rolling to Manuela Monleón, he wanted to share a list of resources on the web. I am sure that they will be very useful. 

· Web of Sociedad Española de Cuidados Paliativos (SECPAL)

· Asociación Española de Enfermería en Cuidados Paliativos (AECPAL)

· Web of Sociedad Europea de Cuidados Paliativos (EAPC)

· Blog de la EAPC

· Prague Charterrecognition of Palliative Care as a Human Right 

· The World Hospice Palliative Care Association

· International Observatory on End of Life Care, Lancaster University (UK)

· International Psycho-Oncology Society

· Portal de Cuidados Paliativos, avalado por la SECPAL

· Palliative Care blog: Carreteras Secundarias (only available in Spanish)

· Guía de Práctica Clínica del Ministerio de Sanidad y Consumo de Cuidados Paliativos (2009) (only available in Spanish)

And I would like to add the Collaborative Blog Cuidados Paliativos + visibles, in which of course IC-HU Project will contribute, because all of this is about social, health and Human consciousness. 

Have a nice day,