Arterial Bleeding in Pelvic Trauma: Priorities in Angiographic Embolization Raffaella Niola, MD, a Antonio Pinto, MD, PhD, b Amelia Sparano, MD, b Rosa Ignarra, MD, b Luigia Romano, MD, b and Franco Maglione, MD a Vascular injuries are a major source of morbidity and mortality in patients with blunt pelvic trauma. Up to 40% of patients with pelvic fractures related to blunt traumatic injury experience intra-abdominal or intrapelvic bleeding, which is the major determining factor of mortality. Sources of hemorrhage within the pelvis include injuries to major pelvic arterial and venous structures and vascular damage related to osseous fractures. Among patients with pelvic fractures, up to 20% require emergent transcatheter embo- lization, depending on the type of injury. Angiography is the gold standard for the treatment of pelvic arterial hemorrhage associated with pelvic fractures. Transcatheter techniques provide direct identification of sources of bleed- ing. Selective catheterization and flow-directed particulate emboli can control bleeding from small arteries at sites of injury. Pelvic fractures constitute about 3% of all skeletal fractures and range in severity from low-energy stable fractures to high-energy injuries with unstable fracture patterns. 1-3 Hemodynamic compromise is not uncom- mon in patients suffering from unstable pelvic frac- ture. Bleeding is usually of venous origin. However, in 10%-20% of the patients, hemodynamic instability is associated with arterial hemorrhage. 4 Mortality of up to 50% has been reported despite effective control of bleeding. 5 Digital subtraction angiography (DSA) has traditionally been the preferred method used to detect pelvic arterial injuries and to treat active arterial hemorrhage in patients with blunt pelvic trauma. 6 Improvements in computed tomographic (CT) tech- nology have facilitated implementation of CT angiog- raphy, which is beginning to replace DSA in the evaluation of patients with acute trauma 7 : with the advent of 64-channel multidetector CT, the ability to seamlessly integrate multiphasic, whole-body imaging into the evaluation of trauma patients has emerged. 8-12 The decision to perform pelvic CT angiography in addition to routine trauma imaging is made by the attending trauma surgeon on the basis of the initial clinical assessment in conjunction with radiographic findings. Pelvic CT angiography is useful in assessing vascular injuries. Arterial phase imaging provides optimal visualization of the arterial structures and, in combination with portal venous phase imaging, can help differentiate between arterial and venous hemor- rhage. Arterial injuries occur in direct relation to the mechanism and severity of injury and are largely associated with the degree of instability of the pelvic ring. Arterial injuries that may be depicted on CT angiographic images include occlusion, dissection, pseudoaneurysm, and arteriovenous fistula. Active arterial hemorrhage may be identified at pelvic CT angiography. Use of multiphasic acquisitions, including arterial, venous, and delayed phase imaging, makes distinguishing between arterial and venous hemorrhage possible. Venous injuries also represent a significant cause of morbidity and mortality in patients with blunt pelvic trauma. Although pelvic stabilization may be sufficient to treat a substantial number of venous injuries, 13-15 continued venous hemorrhage may be identified on CT images. Foci of extravascular hyper- attenuation that are identified only on portal venous phase images, without corresponding abnormalities on arterial phase images, likely represent areas of venous hemorrhage. It is therefore important to identify the predictors of the need for conventional angiography From the a Department of Diagnostic Imaging, Section of Vascular and Interventional Radiology, “A. Cardarelli” Hospital, Naples, Italy; and b Department of Diagnostic Imaging, Section of General and Emergency Radiology, “A. Cardarelli” Hospital, Naples, Italy. Reprint requests: Raffaella Niola, MD, Department of Diagnostic Imaging, Section of Vascular and Interventional Radiology, “A. Cardarelli” Hospi- tal, Naples, Italy. E-mail: raffaellaniola@tiscali.it. Curr Probl Diagn Radiol 2012;41:93-101. © 2012 Mosby, Inc. All rights reserved. 0363-0188/$36.00 + 0 doi:10.1067/j.cpradiol.2011.07.008 Curr Probl Diagn Radiol, May/June 2012 93