Multidetector CT Angiography Highly Sensitive, Specific for Vascular Extremity Injury

BOSTON – Physical examination is still the gold standard for patients with vascular injury of the extremities, and can reduce unnecessary imaging in the majority of patients. But when imaging is called for, multidetector CT angiography is a highly sensitive and specific noninvasive option, said Dr. Kenji Inaba.

In a prospective study involving 73 patients with extremity trauma but uncertain signs of vascular injury, multidetector CT angiography (MCTA) flagged 24 injuries, all but 1 of which were confirmed in the operating room, Dr. Inaba said at the annual meeting of the American Association for the Surgery of Trauma.

“There are a lot of potential advantages to using CT angio: It’s widely available everywhere using preexisting hardware and software, it’s fast and becoming faster, and it’s available 24 hours a day without any delay from calling the interventional radiology team in,” said Dr. Inaba from the division of trauma and surgical critical care at the Los Angeles County Hospital/University of Southern California Medical Center.

Because the technique is not performed under a sterile field, it simplifies patient monitoring, and it produces “surgeon-friendly,” three-dimensional multiplanar images.

“Not only does it let us look at the vasculature, it also lets us look at soft tissues and all the bone structures as well. Unlike conventional angio, it doesn’t need a central arterial catheterization – all the contrast is given through peripheral venous access,” Dr. Inaba said.

He and his colleagues took a prospective look at the ability of MCTA to detect arterial injuries in the arms and legs. They studied patients aged 16 and older treated from January 2009 to August 2010 who presented with either penetrating injury, blunt crush, or long bone fracture or dislocation. Arm injuries could be anywhere down to the wrist, and leg injuries were anywhere down to the ankle.

A total of 635 patients were assigned to one of three treatment groups based on findings at physical examination. Those with hard signs of vascular injury (35 patients) were sent into surgery. Hard signs were defined as absent pulses, active hemorrhage, expanding/pulsatile hematoma, bruit or thrill, or shock unresponsive to resuscitation.

Those with no signs (527 patients) were put on observation for a minimum of 24 hours. Patients were considered to have no vascular injury signs if they had asymptomatic limbs and an ankle-brachial index (ABI) or a brachial-brachial index (BBI) of 0.9 or greater.

The remaining 73 patients had “soft” signs, such as venous oozing, nonexpanding or nonpulsatile hematoma, diminished pulses, or an abnormal ankle-brachial/brachial-brachial index. These patients underwent MCTA.

The patients underwent a total of 89 MCTA studies. The mean age was 30.3 years (range, 16-77); 88% were male; and 70% had penetrating injuries. The mean injury severity score was 10 plus or minus 8.1, and 38% of the patients had an abbreviated injury score of 3 or higher. Nearly half of all injuries were to the thigh. Other sites were the upper arm, knee, groin, shoulder/axilla, forearm, elbow, and calf.

Indications for MCTA included nonexpanding or nonpulsatile hematoma or an abnormal ABI or BBI (in 35.6% each), venous oozing in 21.9%, diminished pulses in 19.2%, and proximity of injury to a major vessel in 15.1%; some patients had more than one indication. Imaging for proximity was not one of the study indications, Dr. Inaba noted. The investigators classified the MCTA findings as either nondiagnostic, negative, or positive. Seven of the 89 studies were deemed to be nondiagnostic: 5 because of retained shotgun pellets or bullets causing artifacts that obscured potential injuries, and 2 because of technical problems that occurred with unfamiliar equipment in the new Los Angeles County facility during the early months of the study. These patients underwent conventional angiography, and there were no missed diagnoses, Dr. Inaba said.

Most of the MCTA studies (58) were negative. The patients were followed for a minimum of 24 hours (range, 1-41 days), and none had clinically significant missed injuries.

The remaining 24 studies were positive, and all but 1, a posterior tibular injury, were confirmed in the operating room.

“CT angio was not only able to locate the site of the injury, but it was also able to well characterize the injury itself,” Dr. Inaba said.

Limitations of the study included a lack of confirmatory imaging in the patients with negative studies because of the cost, time, and unjustifiable extra radiation exposure. In addition, 21% of these patients were sent home after 24 hours of observation, and it’s possible that CT angiography missed injuries that were later picked up at another hospital. The investigators also relied on final radiology reports rather than de novo blinded readings.

“These CT scanners are improving on a daily basis, and there’s true concern that we may be detecting clinically nonsignificant injuries,” he added.

Although Dr. Inaba said that the study showed MCTA sensitivity and specificity for vascular injury to be 100% each, the inconclusive study results indicate that neither could be 100%, said Dr. David Spain of the division of trauma/critical care at Stanford (Calif.) University Hospital. He was the invited discussant.

“The sensitivity and specificity analysis isn’t just for CTA. It’s actually for a structured physical exam followed by a CTA,” Dr. Spain commented.

The study was internally funded. The authors said they had no conflicts of interest.

BOSTON – Physical examination is still the gold standard for patients with vascular injury of the extremities, and can reduce unnecessary imaging in the majority of patients. But when imaging is called for, multidetector CT angiography is a highly sensitive and specific noninvasive option, said Dr. Kenji Inaba.

In a prospective study involving 73 patients with extremity trauma but uncertain signs of vascular injury, multidetector CT angiography (MCTA) flagged 24 injuries, all but 1 of which were confirmed in the operating room, Dr. Inaba said at the annual meeting of the American Association for the Surgery of Trauma.

“There are a lot of potential advantages to using CT angio: It’s widely available everywhere using preexisting hardware and software, it’s fast and becoming faster, and it’s available 24 hours a day without any delay from calling the interventional radiology team in,” said Dr. Inaba from the division of trauma and surgical critical care at the Los Angeles County Hospital/University of Southern California Medical Center.

Because the technique is not performed under a sterile field, it simplifies patient monitoring, and it produces “surgeon-friendly,” three-dimensional multiplanar images.

“Not only does it let us look at the vasculature, it also lets us look at soft tissues and all the bone structures as well. Unlike conventional angio, it doesn’t need a central arterial catheterization – all the contrast is given through peripheral venous access,” Dr. Inaba said.

He and his colleagues took a prospective look at the ability of MCTA to detect arterial injuries in the arms and legs. They studied patients aged 16 and older treated from January 2009 to August 2010 who presented with either penetrating injury, blunt crush, or long bone fracture or dislocation. Arm injuries could be anywhere down to the wrist, and leg injuries were anywhere down to the ankle.

A total of 635 patients were assigned to one of three treatment groups based on findings at physical examination. Those with hard signs of vascular injury (35 patients) were sent into surgery. Hard signs were defined as absent pulses, active hemorrhage, expanding/pulsatile hematoma, bruit or thrill, or shock unresponsive to resuscitation.

Those with no signs (527 patients) were put on observation for a minimum of 24 hours. Patients were considered to have no vascular injury signs if they had asymptomatic limbs and an ankle-brachial index (ABI) or a brachial-brachial index (BBI) of 0.9 or greater.

The remaining 73 patients had “soft” signs, such as venous oozing, nonexpanding or nonpulsatile hematoma, diminished pulses, or an abnormal ankle-brachial/brachial-brachial index. These patients underwent MCTA.

The patients underwent a total of 89 MCTA studies. The mean age was 30.3 years (range, 16-77); 88% were male; and 70% had penetrating injuries. The mean injury severity score was 10 plus or minus 8.1, and 38% of the patients had an abbreviated injury score of 3 or higher. Nearly half of all injuries were to the thigh. Other sites were the upper arm, knee, groin, shoulder/axilla, forearm, elbow, and calf.

Indications for MCTA included nonexpanding or nonpulsatile hematoma or an abnormal ABI or BBI (in 35.6% each), venous oozing in 21.9%, diminished pulses in 19.2%, and proximity of injury to a major vessel in 15.1%; some patients had more than one indication. Imaging for proximity was not one of the study indications, Dr. Inaba noted. The investigators classified the MCTA findings as either nondiagnostic, negative, or positive. Seven of the 89 studies were deemed to be nondiagnostic: 5 because of retained shotgun pellets or bullets causing artifacts that obscured potential injuries, and 2 because of technical problems that occurred with unfamiliar equipment in the new Los Angeles County facility during the early months of the study. These patients underwent conventional angiography, and there were no missed diagnoses, Dr. Inaba said.

Most of the MCTA studies (58) were negative. The patients were followed for a minimum of 24 hours (range, 1-41 days), and none had clinically significant missed injuries.

The remaining 24 studies were positive, and all but 1, a posterior tibular injury, were confirmed in the operating room.

“CT angio was not only able to locate the site of the injury, but it was also able to well characterize the injury itself,” Dr. Inaba said.

Limitations of the study included a lack of confirmatory imaging in the patients with negative studies because of the cost, time, and unjustifiable extra radiation exposure. In addition, 21% of these patients were sent home after 24 hours of observation, and it’s possible that CT angiography missed injuries that were later picked up at another hospital. The investigators also relied on final radiology reports rather than de novo blinded readings.

“These CT scanners are improving on a daily basis, and there’s true concern that we may be detecting clinically nonsignificant injuries,” he added.

Although Dr. Inaba said that the study showed MCTA sensitivity and specificity for vascular injury to be 100% each, the inconclusive study results indicate that neither could be 100%, said Dr. David Spain of the division of trauma/critical care at Stanford (Calif.) University Hospital. He was the invited discussant.

“The sensitivity and specificity analysis isn’t just for CTA. It’s actually for a structured physical exam followed by a CTA,” Dr. Spain commented.

The study was internally funded. The authors said they had no conflicts of interest.

BOSTON – Physical examination is still the gold standard for patients with vascular injury of the extremities, and can reduce unnecessary imaging in the majority of patients. But when imaging is called for, multidetector CT angiography is a highly sensitive and specific noninvasive option, said Dr. Kenji Inaba.

In a prospective study involving 73 patients with extremity trauma but uncertain signs of vascular injury, multidetector CT angiography (MCTA) flagged 24 injuries, all but 1 of which were confirmed in the operating room, Dr. Inaba said at the annual meeting of the American Association for the Surgery of Trauma.

“There are a lot of potential advantages to using CT angio: It’s widely available everywhere using preexisting hardware and software, it’s fast and becoming faster, and it’s available 24 hours a day without any delay from calling the interventional radiology team in,” said Dr. Inaba from the division of trauma and surgical critical care at the Los Angeles County Hospital/University of Southern California Medical Center.

Because the technique is not performed under a sterile field, it simplifies patient monitoring, and it produces “surgeon-friendly,” three-dimensional multiplanar images.

“Not only does it let us look at the vasculature, it also lets us look at soft tissues and all the bone structures as well. Unlike conventional angio, it doesn’t need a central arterial catheterization – all the contrast is given through peripheral venous access,” Dr. Inaba said.

He and his colleagues took a prospective look at the ability of MCTA to detect arterial injuries in the arms and legs. They studied patients aged 16 and older treated from January 2009 to August 2010 who presented with either penetrating injury, blunt crush, or long bone fracture or dislocation. Arm injuries could be anywhere down to the wrist, and leg injuries were anywhere down to the ankle.

A total of 635 patients were assigned to one of three treatment groups based on findings at physical examination. Those with hard signs of vascular injury (35 patients) were sent into surgery. Hard signs were defined as absent pulses, active hemorrhage, expanding/pulsatile hematoma, bruit or thrill, or shock unresponsive to resuscitation.

Those with no signs (527 patients) were put on observation for a minimum of 24 hours. Patients were considered to have no vascular injury signs if they had asymptomatic limbs and an ankle-brachial index (ABI) or a brachial-brachial index (BBI) of 0.9 or greater.

The remaining 73 patients had “soft” signs, such as venous oozing, nonexpanding or nonpulsatile hematoma, diminished pulses, or an abnormal ankle-brachial/brachial-brachial index. These patients underwent MCTA.

The patients underwent a total of 89 MCTA studies. The mean age was 30.3 years (range, 16-77); 88% were male; and 70% had penetrating injuries. The mean injury severity score was 10 plus or minus 8.1, and 38% of the patients had an abbreviated injury score of 3 or higher. Nearly half of all injuries were to the thigh. Other sites were the upper arm, knee, groin, shoulder/axilla, forearm, elbow, and calf.

Indications for MCTA included nonexpanding or nonpulsatile hematoma or an abnormal ABI or BBI (in 35.6% each), venous oozing in 21.9%, diminished pulses in 19.2%, and proximity of injury to a major vessel in 15.1%; some patients had more than one indication. Imaging for proximity was not one of the study indications, Dr. Inaba noted. The investigators classified the MCTA findings as either nondiagnostic, negative, or positive. Seven of the 89 studies were deemed to be nondiagnostic: 5 because of retained shotgun pellets or bullets causing artifacts that obscured potential injuries, and 2 because of technical problems that occurred with unfamiliar equipment in the new Los Angeles County facility during the early months of the study. These patients underwent conventional angiography, and there were no missed diagnoses, Dr. Inaba said.

Most of the MCTA studies (58) were negative. The patients were followed for a minimum of 24 hours (range, 1-41 days), and none had clinically significant missed injuries.

The remaining 24 studies were positive, and all but 1, a posterior tibular injury, were confirmed in the operating room.

“CT angio was not only able to locate the site of the injury, but it was also able to well characterize the injury itself,” Dr. Inaba said.

Limitations of the study included a lack of confirmatory imaging in the patients with negative studies because of the cost, time, and unjustifiable extra radiation exposure. In addition, 21% of these patients were sent home after 24 hours of observation, and it’s possible that CT angiography missed injuries that were later picked up at another hospital. The investigators also relied on final radiology reports rather than de novo blinded readings.

“These CT scanners are improving on a daily basis, and there’s true concern that we may be detecting clinically nonsignificant injuries,” he added.

Although Dr. Inaba said that the study showed MCTA sensitivity and specificity for vascular injury to be 100% each, the inconclusive study results indicate that neither could be 100%, said Dr. David Spain of the division of trauma/critical care at Stanford (Calif.) University Hospital. He was the invited discussant.

“The sensitivity and specificity analysis isn’t just for CTA. It’s actually for a structured physical exam followed by a CTA,” Dr. Spain commented.

The study was internally funded. The authors said they had no conflicts of interest.