Whole-body MSCT does ‘triple rule-out’ of head and neck injuries

Whole-body multislice CT can accurately diagnose musculoskeletal, vascular, and brain injuries in patients with blunt head and neck trauma without additional neck MSCT angiography, according to University of Maryland researchers.

Blunt cerebrovascular injuries can lead to stroke or lethal episodes. Lesions include arteriovenous fistulas, pseudoaneurysms, and dissections, which tend to be asymptomatic and thereby underdiagnosed. The clinical literature recommends careful screening and treatment before symptoms and complications appear. Catheter angiography remains the standard of care, but it is invasive, expensive, and labor-intensive.

In 2003, Maryland's R. Adams Cowley Shock Trauma Center in Baltimore replaced cath angio with whole-body screening of blunt trauma patients using a 16-detector CT scanner. Until recently, patients with signs of cerebrovascular injuries also underwent neck MSCT angiography. But screeners noticed that the contrast-enhanced whole-body MSCT protocol could diagnose many of these injuries, said principal investigator Dr. Clint W. Sliker, an assistant professor of radiology.

From May 2003 to March 2006, Sliker and colleagues retrospectively identified 108 blunt trauma patients who underwent whole-body MSCT, neck MSCTA, or both protocols, followed by angiography. They found that whole-body MSCT was just as accurate as neck MSCTA and may make the additional exam unnecessary. They published their results in the American Journal of Roentgenology (2008;190:790-799).

Angiography confirmed blunt cerebrovascular lesions in 83 patients, about one-third of whom had multiple injury sites. Most injuries were detected in cervical arterial segments. Sensitivity and specificity for cervical internal carotid artery injuries were 69% and 82%, respectively, for whole-body MSCT and 64% and 94% for MSCTA. Sensitivity and specificity for cervical vertebral artery injuries for whole-body MSCT were 74% and 91%, respectively, and 68% and 100% for MSCTA. In 17 patients scanned with both protocols, the differences were not statistically significantly (carotid arteries, p = 1.00; vertebral arteries, p = 0.68).

"Similar to the so-called triple rule-out scanning protocols used to evaluate patients for acute chest pain, we are seeing the potential for one MDCT to provide a comprehensive and global evaluation for skeletal, vascular, and organ injuries in acutely injured patients following blunt trauma," Sliker said.

Accurate sensitivity assessments for both MSCT and MSCTA and injury-type biases account for the main limitations of the study. A large prospective trial comparing the MSCT protocols with catheter angiography could yield some answers, but such an undertaking would be difficult and ethically challenging. The comparably high specificities of both protocols, however, allow for management decisions to be made reliably on the basis of positive whole-body MSCT results, according to Sliker.

Routine use of whole-body MSCT could facilitate diagnosis and treatment of asymptomatic blunt cerebrovascular injuries in patients without typical risk factors, he said.

"Since the whole-body MDCT can serve as a first-line means to screen for blunt cerebrovascular injuries, radiologists must maintain a high index of suspicion for these injuries, although the primary target for scanning the head and neck may be the face and cervical spine, respectively, rather than the neck arteries," Sliker said.

For more information from the Diagnostic Imaging archives:

CT angiography excels for head and neck vascular trauma

Whole-body CTA proves effective in detecting vascular injury in head and neck trauma patients

Multislice CTA gains edge over DSA for brain aneurysm detection

CTA trauma scan detects blunt carotid artery injury