The traditional teaching of radiologic screening in the multiply injured blunt trauma patient by the Advanced Trauma Life Support (ATLS) course has been to obtain initial radiographs of the lateral cervical spine, anteroposterior (AP) chest, and AP pelvis.¹ For the most part, this adage remains useful, as these initial films will identify the injuries that may require the most immediate attention following the primary survey. Following the secondary survey, thoracolumbar (T-L) spine radiographs and films of any extremities should then be obtained if there is any suspicion of injury to these areas.

The crosstable lateral cervical spine radiograph must include visualization of the base of the skull, all seven cervical vertebrae without overlying foreign bodies, and the top of the first thoracic vertebra. The initial lateral view should rapidly identify an unstable cervical fracture. Early knowledge of cervical spine injury may be especially important if respiratory insufficiency is present and intubation is needed. AP and open-mouth odontoid views or computed tomography (CT) scan can be obtained to supplement this view after the secondary survey.

The supine AP chest radiograph rapidly identifies potentially life-threatening injuries such as pneumothorax and hemothorax. The early detection of rib fractures, pulmonary contusion, or diaphragm rupture may also be made. The initial chest x-ray may explain asymmetric lung sounds, dyspnea, or hypoxia on initial presentation. It is often necessary to use an upright chest x-ray or CT to definitively exclude mediastinal hemorrhage from aortic injury.

The supine AP pelvic radiograph is used to identify obvious pelvic fractures or ring disruption from ligamentous injury. Abnormalities on this film may help explain any hemodynamic instability from potential pelvic hemorrhage. If any fracture is identified, a subsequent CT scan should be obtained. The initial trio of x-rays are most essential in patients in which hemodynamics or pulmonary function is unstable and the early diagnosis of life-threatening injuries is critical.

The Statscan machine is a low-dose digital radiographic unit that can scan the entire body in <13 seconds. The device was developed in South Africa by LODOX Ltd.
(Johannesburg) and has since been used in a few centers in the United States. The physical unit appears somewhat similar to a CT scan device, but is somewhat smaller. The patient to be studied is transferred onto the Statscan table and scanning can be performed in the AP, lateral, or any oblique angle. The product of the scan is a full-body radiographic image of the patient projected electronically onto a local monitor or transmitted through an imaging network.

The utility of the Statscan in the initial evaluation for trauma is currently under investigation, but early results are promising for the technology. The most obvious benefit appears to be to expedite rapid radiographic evaluation, triage, and emergent management decisions in multiply injured trauma patients. In a prospective evaluation of the LODOX device, overall patient time required was only 5 to 6 minutes for LODOX compared to 8 to 48 minutes for conventional x-rays.²

The workflow advantage to an early full-body radiograph has considerable promise in the initial evaluation of trauma. Several patient situations would be most amenable to Statscan radiographic survey. The blunt multiply injured patient with altered sensorium, comatose, or intubated and sedated will have an unreliable history and physical examination. The blunt trauma patient who says “it hurts everywhere!” would otherwise require an extraordinary number of radiographic views. The patient with multiple gunshot or shotgun wounds in which the trajectory or number of remaining missiles must be assessed would otherwise have a risk of a missed injury with just a few conventional films.

The use of ultrasonography (US) by trauma surgeons and emergency physicians has clearly established a rapid noninvasive technique to make the diagnosis of hemoperitoneum and hemopericardium. US is portable, rapid, and can be interpreted in real time. The ability to repeat ultrasound, if indeterminate, is also quite attractive. US, however, must be carefully mastered before it is useful. Casual use of ultrasound imaging can produce disastrous results if false-negative studies are obtained. Practitioners should be adequately educated and obtain sufficient experience under supervision before utilizing ultrasound independently.

We have witnessed rapid improvements in CT technology. We have incorporated its diagnostic superiority to a vast array of disease processes, some of which we would never have traditionally evaluated by CT imaging (see Table 1). CT is able to identify organ-specific injury in virtually every body cavity. The ability to alter image windows allows vascular, bony, and soft tissue structures to be evaluated. Although the acquisition of the images may be rapid, complicated reconstruction does take some time. Transport to and from the scanner also requires time and the use of nursing resources. In most cases, torso CT scanning requires both oral and intravenous contrast with a small risk of aspiration and/or contrast allergic reaction.

The sensitivity of CT has improved and screening with CT has become increasingly popular. CT is no longer considered only an imaging modality for directed diagnosis. The multidetector format has made it more practical to perform scanning of larger body sections in relatively short periods of time, rather than scanning several focused and limited segments. The advantages of CT scanning are increasingly outweighing the disadvantages. In blunt, multiply injured patients, it is now common to obtain CT scans of the head, facial bones, cervical spine, chest, abdomen, and pelvis in a single setting for a relatively complete full-body survey.

CT angiography is also replacing conventional angiography as the initial method to evaluate the possibility of vascular injury in various sites in the body. It is less invasive than conventional angiography and many centers are gaining much more experience utilizing these studies. Conventional angiography is now used for therapeutic hemostasis, where we have expanded methods of embolization and angioplasty. Angiographic stenting for vascular injuries has increasing applicability, especially in high-risk surgical patients.

Magnetic resonance imaging (MRI) has a limited use for evaluation of the trauma patient. MRI may still be considered the definitive modality in the detection of acute spinal cord injury and the imaging test of choice for nonskeletal spinal support injuries. Magnetic resonance angiography still has a limited role in the vascular evaluation of trauma patients.

The radiologic assessment for traumatic brain injury is almost exclusively done with CT scan. The indications for obtaining a head CT should be relatively liberal, including any patient with a loss of consciousness, a significant external injury to the head, whether by blunt force or penetrating mechanism, or any patient with an altered sensorium. The noncontrast CT scan of the brain is ideal for detecting parenchymal lesions, extra-axial collections of blood, hematomas with mass effect, and skull fractures. Plain radiographic skull films are now obsolete.

MRI becomes relevant only when investigating for a predisposing lesion or infarct that may have contributed to the traumatic event. It is most useful in investigation of patients in which the clinical findings do not correlate with CT findings. CT is superior to MRI in the detection of acute trauma such as early extra-axial hematoma, skull fractures, and pneumocephalus, but MRI may better evaluate injuries to the brainstem and the multiple shearing injuries seen in the diffuse axonal injury syndrome. A specialized CT-perfusion study of the brain may also be performed as an adjunct.

The detection of skull base fractures is especially difficult on traditional CT scan of the head because the entire skull base may not be adequately imaged and the sections are not sufficiently narrow. The temporal bone CT scan provides more narrow sections at a section angle more suitable to detect skull base fractures.

Any suspicion for facial trauma is an indication for CT scanning of the facial bones. The CT of facial bones should include the facial sinuses, orbital structures, and mandible. The superior sensitivity of CT with multiplanar reconstruction obviates any need for plain film radiography of the face to evaluate for trauma. CT provides all the detailed information important about fracture patterns, displacement, comminution, and associated soft tissue injury.

In the blunt multiply injured patient, facial fractures are at increased risk of being missed, especially in those patients with associated brain injury or altered sensorium. In a 5-year review of almost 5,000 patients undergoing head CT for trauma, 12% were found to have associated facial fracture.³ This study advocated more liberal use of facial CT when performing head CT for blunt trauma.

Patients who are awake, alert, reliable, and lack any neck pain or tenderness may have the cervical spine cleared without any radiographic evaluation. Clearance of the cervical spine is one of the most controversial areas involving imaging in trauma. The inadequacy of the plain radiographic techniques and the need for clinical correlation has made this evaluation especially difficult. Still existing published protocols recommend that the initial studies performed should be plain radiographs. Various algorithms have been proposed to clear the cervical spine in trauma patients, with most requiring a minimum of three views.⁴

An adequate lateral view must portray the C7-T1 junction. It is typically necessary for someone to pull down on the patient’s arms to clear the shoulders from obstructing the radiographic view. Even with the additional pulling, this image is frequently unable to project the cervicothoracic junction. The swimmer’s view is a potential adjunctive view, but is also often limited in quality.

The open-mouth odontoid view is frequently a technical challenge to obtain an adequate view. Many trauma patients are simply not able to open their mouth for this view. Existing algorithms recommend supplementing the radiographic imaging with CT scanning directed at areas without adequate visualization. With multidetector CT technology, it is now common practice to scan the entire cervical spine.

MRI is reserved for those patients presenting with acute neurologic deficit that may be a result of a cervical spine injury. If the CT scan reveals the pathology, additional imaging may not be necessary before the initiation of treatment. MRI may still provide the additional information regarding the status of the spinal cord and vertebral ligaments. In those patients without overt spinal cord neurologic deficit, MRI scanning may still be important to definitively exclude ligamentous injury before removal of the hard cervical collar.⁵

For those who rely on MRI to definitively clear the cervical spine of ligamentous injury, the unreliable trauma patients present a significant challenge. It remains unclear at what time the MRI should be obtained to have the greatest sensitivity for ligamentous injury. Furthermore, trauma patients are a difficult group to obtain an adequate history to exclude the presence of metallic foreign bodies. Critically ill and hemodynamically unstable patients on moderate ventilator support may not be good candidates to go for MRI. Therefore, it may appear more practical to simply leave the cervical collar in place in these patients.