CT Angiography Screens for Blunt Cerebrovascular Injuries

ATLANTA — Computed tomographic angiography with a 16-channel detector can be used to accurately screen patients for blunt cervical vascular and cerebrovascular injuries, according to two studies presented at the annual meeting of the American Association for the Surgery of Trauma.

“Though ours was a relatively small study population and future studies are needed to focus on the accuracy of grading by CTA, this technology should be considered the screening standard for patients at risk of blunt cervical vascular injury,” said chief author Alexander L. Eastman, M.D., of the University of Texas Southwestern Medical Center in Dallas. “The severe and unforgiving nature of an undiagnosed blunt cervical vascular injury presents a real problem. Given the large differences in treated and untreated stroke rates, the principle of screening and early detection is vital. Despite this, the definition of an ideal screening test remains controversial, [though] catheter arteriography remains the 'gold standard.'”

In previous head-to-head studies using less powerful scanners, CTA failed to match the performances of catheter arteriography (CA). When a new 16-channel machine arrived at Parkland Hospital, the Dallas researchers decided to put it to the test.

Data from all patients presenting to their level I trauma center at risk for blunt cervical vascular injury were collected prospectively. During an 8-month period, each patient was evaluated with CTA and the findings confirmed with standard CA of the head, neck, and aortic arch.

Of more than 3,000 trauma admissions during 8 months, 148 patients were deemed at risk for blunt cervical vascular injury. A total of 135 patients received both CTA and CA, and 13 received CTA only, due primarily to patient rejection of CA and discharge prior to CA. Among 41 patients, 43 blunt cervical vascular injuries were identified, yielding an overall incidence of 1.4% and an incidence within the screened population of more than 30%. Results of the two procedures were concordant in 42 of 43 cases with blunt cervical vascular injuries.

The remaining patients had normal CTAs confirmed by a normal CA, the investigators wrote.

The overall incidence of carotid artery injury (CAI) was 0.6% and vertebral artery injury (VAI) was 96%. Of the VAIs, 96% were associated with at least one cervical spine fracture. In the patients who underwent both CTA and CA, the detection sensitivity of CTA was 100% for CAI and 96% for VAI.

The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CTA for blunt cervical vascular injury were 97.1%, 100%, 100%, 98.9%, and 99.3%, respectively, they said.

An additional enhancement offered by CTA is the ability to subtract other anatomic structures and focus on the vascular system exclusively, Dr. Eastman said. Vertebral artery injuries also are impressive when viewed at the CT workstation, he added.

When patients with negative CTA who did not have an angiogram were followed up at 3–12 months, none were found to have an injury or neurologic sequelae.

Following Dr. Eastman's presentation, discussant David A. Spain, M.D., agreed that 16-slice CTA is ready for prime time. However, “Is it ready for non-prime time?” asked Dr. Spain, who is with the Stanford University Medical Center, Stanford, Calif. “Who reads these studies at 2 a.m.? Three-dimensional reconstructions are very important to accurate interpretations, and if no one is available to read the exam, how long before you have a definitive answer as to whether these patients have an injury?” he added.

“I think obviously there's going to be some house staff reading at first,” replied Dr. Eastman. “We're lucky at our institution that our neuroradiologists are exquisitely helpful … so you get a reading almost immediately.”

CTA vs. ART

The second study, conducted at Rhode Island Hospital and Brown Medical School in Providence, compared 16-slice CTA with 4-vessel cerebral arteriography (ART) in screening for blunt cerebrovascular injuries.

Screening detects many asymptomatic cerebrovascular injuries. “However, it has not been proven to prevent strokes, and thus many centers have been reluctant to implement screening protocols,” they wrote. “It is particularly difficult to justify because ART, the gold-standard diagnostic test, is invasive and resource intensive.”

“We developed our screening protocol using arteriography for symptomatic patients because … we need a gold standard test when a patient is having symptoms or signs consistent with an injury,” said lead author Walter L. Biffl, M.D. The investigators settled on 16-slice CTA for patients with high-risk mechanisms and injury patterns. To further capture any group that may be at risk, they enlarged the study group to include any patient with cranial or cervical trauma who was undergoing a CT scan.

The protocol called for CTA in all trauma patients with cranial or cervical trauma undergoing CT scanning. Any abnormality was further investigated with ART, and patients were followed for neurologic changes. The investigators reviewed records to determine if clinical injuries were missed by CTA, and then compared ART and CTA images.

Between June 2004 and February 2005, the team did 225 CTAs. A total of 17 patients (7.5%) were diagnosed with blunt cerebrovascular injuries, including 11 carotid and 6 vertebral injuries. CTA did not miss any clinically important blunt cerebrovascular injury, the researchers said.

“Importantly, nobody during the study period who had had a normal CTA developed signs or symptoms of a vascular injury, and that was what we set out to explore,” Dr. Biffl said. “The disconcerting thing in this study is that two patients who didn't meet the screening criteria presented with symptoms related to a vascular injury.”

One of those patients was an elderly man who had been in a minor auto accident. He was evaluated and sent home from the emergency department, but returned with persistent headache and Horner Syndrome. He was found to have dissection of the carotid artery. The other patient was a young woman who had fractures of the femur and clavicle who, because she didn't have cranial or cervical trauma, didn't undergo a CTA. She woke up the next day in the orthopedic service with a stroke.

“We've concluded from this study that CTA is a reliable, noninvasive screening test for clinically significant blunt cervical vascular injuries,” Dr. Biffl said. “We need multicenter prospective trials to clarify the risk factors and to assess the accuracy of noninvasive screening tests and to evaluate the efficacy of treatment strategies,” he added.

ATLANTA — Computed tomographic angiography with a 16-channel detector can be used to accurately screen patients for blunt cervical vascular and cerebrovascular injuries, according to two studies presented at the annual meeting of the American Association for the Surgery of Trauma.

“Though ours was a relatively small study population and future studies are needed to focus on the accuracy of grading by CTA, this technology should be considered the screening standard for patients at risk of blunt cervical vascular injury,” said chief author Alexander L. Eastman, M.D., of the University of Texas Southwestern Medical Center in Dallas. “The severe and unforgiving nature of an undiagnosed blunt cervical vascular injury presents a real problem. Given the large differences in treated and untreated stroke rates, the principle of screening and early detection is vital. Despite this, the definition of an ideal screening test remains controversial, [though] catheter arteriography remains the 'gold standard.'”

In previous head-to-head studies using less powerful scanners, CTA failed to match the performances of catheter arteriography (CA). When a new 16-channel machine arrived at Parkland Hospital, the Dallas researchers decided to put it to the test.

Data from all patients presenting to their level I trauma center at risk for blunt cervical vascular injury were collected prospectively. During an 8-month period, each patient was evaluated with CTA and the findings confirmed with standard CA of the head, neck, and aortic arch.

Of more than 3,000 trauma admissions during 8 months, 148 patients were deemed at risk for blunt cervical vascular injury. A total of 135 patients received both CTA and CA, and 13 received CTA only, due primarily to patient rejection of CA and discharge prior to CA. Among 41 patients, 43 blunt cervical vascular injuries were identified, yielding an overall incidence of 1.4% and an incidence within the screened population of more than 30%. Results of the two procedures were concordant in 42 of 43 cases with blunt cervical vascular injuries.

The remaining patients had normal CTAs confirmed by a normal CA, the investigators wrote.

The overall incidence of carotid artery injury (CAI) was 0.6% and vertebral artery injury (VAI) was 96%. Of the VAIs, 96% were associated with at least one cervical spine fracture. In the patients who underwent both CTA and CA, the detection sensitivity of CTA was 100% for CAI and 96% for VAI.

The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CTA for blunt cervical vascular injury were 97.1%, 100%, 100%, 98.9%, and 99.3%, respectively, they said.

An additional enhancement offered by CTA is the ability to subtract other anatomic structures and focus on the vascular system exclusively, Dr. Eastman said. Vertebral artery injuries also are impressive when viewed at the CT workstation, he added.

When patients with negative CTA who did not have an angiogram were followed up at 3–12 months, none were found to have an injury or neurologic sequelae.

Following Dr. Eastman's presentation, discussant David A. Spain, M.D., agreed that 16-slice CTA is ready for prime time. However, “Is it ready for non-prime time?” asked Dr. Spain, who is with the Stanford University Medical Center, Stanford, Calif. “Who reads these studies at 2 a.m.? Three-dimensional reconstructions are very important to accurate interpretations, and if no one is available to read the exam, how long before you have a definitive answer as to whether these patients have an injury?” he added.

“I think obviously there's going to be some house staff reading at first,” replied Dr. Eastman. “We're lucky at our institution that our neuroradiologists are exquisitely helpful … so you get a reading almost immediately.”

CTA vs. ART

The second study, conducted at Rhode Island Hospital and Brown Medical School in Providence, compared 16-slice CTA with 4-vessel cerebral arteriography (ART) in screening for blunt cerebrovascular injuries.

Screening detects many asymptomatic cerebrovascular injuries. “However, it has not been proven to prevent strokes, and thus many centers have been reluctant to implement screening protocols,” they wrote. “It is particularly difficult to justify because ART, the gold-standard diagnostic test, is invasive and resource intensive.”

“We developed our screening protocol using arteriography for symptomatic patients because … we need a gold standard test when a patient is having symptoms or signs consistent with an injury,” said lead author Walter L. Biffl, M.D. The investigators settled on 16-slice CTA for patients with high-risk mechanisms and injury patterns. To further capture any group that may be at risk, they enlarged the study group to include any patient with cranial or cervical trauma who was undergoing a CT scan.

The protocol called for CTA in all trauma patients with cranial or cervical trauma undergoing CT scanning. Any abnormality was further investigated with ART, and patients were followed for neurologic changes. The investigators reviewed records to determine if clinical injuries were missed by CTA, and then compared ART and CTA images.

Between June 2004 and February 2005, the team did 225 CTAs. A total of 17 patients (7.5%) were diagnosed with blunt cerebrovascular injuries, including 11 carotid and 6 vertebral injuries. CTA did not miss any clinically important blunt cerebrovascular injury, the researchers said.

“Importantly, nobody during the study period who had had a normal CTA developed signs or symptoms of a vascular injury, and that was what we set out to explore,” Dr. Biffl said. “The disconcerting thing in this study is that two patients who didn't meet the screening criteria presented with symptoms related to a vascular injury.”

One of those patients was an elderly man who had been in a minor auto accident. He was evaluated and sent home from the emergency department, but returned with persistent headache and Horner Syndrome. He was found to have dissection of the carotid artery. The other patient was a young woman who had fractures of the femur and clavicle who, because she didn't have cranial or cervical trauma, didn't undergo a CTA. She woke up the next day in the orthopedic service with a stroke.

“We've concluded from this study that CTA is a reliable, noninvasive screening test for clinically significant blunt cervical vascular injuries,” Dr. Biffl said. “We need multicenter prospective trials to clarify the risk factors and to assess the accuracy of noninvasive screening tests and to evaluate the efficacy of treatment strategies,” he added.

ATLANTA — Computed tomographic angiography with a 16-channel detector can be used to accurately screen patients for blunt cervical vascular and cerebrovascular injuries, according to two studies presented at the annual meeting of the American Association for the Surgery of Trauma.

“Though ours was a relatively small study population and future studies are needed to focus on the accuracy of grading by CTA, this technology should be considered the screening standard for patients at risk of blunt cervical vascular injury,” said chief author Alexander L. Eastman, M.D., of the University of Texas Southwestern Medical Center in Dallas. “The severe and unforgiving nature of an undiagnosed blunt cervical vascular injury presents a real problem. Given the large differences in treated and untreated stroke rates, the principle of screening and early detection is vital. Despite this, the definition of an ideal screening test remains controversial, [though] catheter arteriography remains the 'gold standard.'”

In previous head-to-head studies using less powerful scanners, CTA failed to match the performances of catheter arteriography (CA). When a new 16-channel machine arrived at Parkland Hospital, the Dallas researchers decided to put it to the test.

Data from all patients presenting to their level I trauma center at risk for blunt cervical vascular injury were collected prospectively. During an 8-month period, each patient was evaluated with CTA and the findings confirmed with standard CA of the head, neck, and aortic arch.

Of more than 3,000 trauma admissions during 8 months, 148 patients were deemed at risk for blunt cervical vascular injury. A total of 135 patients received both CTA and CA, and 13 received CTA only, due primarily to patient rejection of CA and discharge prior to CA. Among 41 patients, 43 blunt cervical vascular injuries were identified, yielding an overall incidence of 1.4% and an incidence within the screened population of more than 30%. Results of the two procedures were concordant in 42 of 43 cases with blunt cervical vascular injuries.

The remaining patients had normal CTAs confirmed by a normal CA, the investigators wrote.

The overall incidence of carotid artery injury (CAI) was 0.6% and vertebral artery injury (VAI) was 96%. Of the VAIs, 96% were associated with at least one cervical spine fracture. In the patients who underwent both CTA and CA, the detection sensitivity of CTA was 100% for CAI and 96% for VAI.

The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CTA for blunt cervical vascular injury were 97.1%, 100%, 100%, 98.9%, and 99.3%, respectively, they said.

An additional enhancement offered by CTA is the ability to subtract other anatomic structures and focus on the vascular system exclusively, Dr. Eastman said. Vertebral artery injuries also are impressive when viewed at the CT workstation, he added.

When patients with negative CTA who did not have an angiogram were followed up at 3–12 months, none were found to have an injury or neurologic sequelae.

Following Dr. Eastman's presentation, discussant David A. Spain, M.D., agreed that 16-slice CTA is ready for prime time. However, “Is it ready for non-prime time?” asked Dr. Spain, who is with the Stanford University Medical Center, Stanford, Calif. “Who reads these studies at 2 a.m.? Three-dimensional reconstructions are very important to accurate interpretations, and if no one is available to read the exam, how long before you have a definitive answer as to whether these patients have an injury?” he added.

“I think obviously there's going to be some house staff reading at first,” replied Dr. Eastman. “We're lucky at our institution that our neuroradiologists are exquisitely helpful … so you get a reading almost immediately.”

CTA vs. ART

The second study, conducted at Rhode Island Hospital and Brown Medical School in Providence, compared 16-slice CTA with 4-vessel cerebral arteriography (ART) in screening for blunt cerebrovascular injuries.

Screening detects many asymptomatic cerebrovascular injuries. “However, it has not been proven to prevent strokes, and thus many centers have been reluctant to implement screening protocols,” they wrote. “It is particularly difficult to justify because ART, the gold-standard diagnostic test, is invasive and resource intensive.”

“We developed our screening protocol using arteriography for symptomatic patients because … we need a gold standard test when a patient is having symptoms or signs consistent with an injury,” said lead author Walter L. Biffl, M.D. The investigators settled on 16-slice CTA for patients with high-risk mechanisms and injury patterns. To further capture any group that may be at risk, they enlarged the study group to include any patient with cranial or cervical trauma who was undergoing a CT scan.

The protocol called for CTA in all trauma patients with cranial or cervical trauma undergoing CT scanning. Any abnormality was further investigated with ART, and patients were followed for neurologic changes. The investigators reviewed records to determine if clinical injuries were missed by CTA, and then compared ART and CTA images.

Between June 2004 and February 2005, the team did 225 CTAs. A total of 17 patients (7.5%) were diagnosed with blunt cerebrovascular injuries, including 11 carotid and 6 vertebral injuries. CTA did not miss any clinically important blunt cerebrovascular injury, the researchers said.

“Importantly, nobody during the study period who had had a normal CTA developed signs or symptoms of a vascular injury, and that was what we set out to explore,” Dr. Biffl said. “The disconcerting thing in this study is that two patients who didn't meet the screening criteria presented with symptoms related to a vascular injury.”

One of those patients was an elderly man who had been in a minor auto accident. He was evaluated and sent home from the emergency department, but returned with persistent headache and Horner Syndrome. He was found to have dissection of the carotid artery. The other patient was a young woman who had fractures of the femur and clavicle who, because she didn't have cranial or cervical trauma, didn't undergo a CTA. She woke up the next day in the orthopedic service with a stroke.

“We've concluded from this study that CTA is a reliable, noninvasive screening test for clinically significant blunt cervical vascular injuries,” Dr. Biffl said. “We need multicenter prospective trials to clarify the risk factors and to assess the accuracy of noninvasive screening tests and to evaluate the efficacy of treatment strategies,” he added.