Computed tomography has revolutionized the management of major trauma. The introduction of whole-body CT (WBCT) — a single rapid acquisition covering the head, cervical spine, chest, abdomen, and pelvis — has made CT the cornerstone of the primary survey in hemodynamically stable polytrauma patients, dramatically reducing time-to-diagnosis for life-threatening injuries compared to the traditional system of sequential organ-by-organ evaluation.

The Whole-Body CT Trauma Protocol

Modern trauma CT is performed as a single-pass acquisition after IV contrast bolus injection, capturing images in multiple phases. A standard protocol includes: non-contrast head and cervical spine CT, followed immediately by contrast-enhanced CT chest, abdomen, and pelvis in the portal venous phase (70–80 seconds after injection). High-energy trauma may additionally require arterial phase imaging of the abdomen when aortic or major vascular injury is suspected, creating a dual-phase (arterial + venous) acquisition. Scan time on modern wide-detector CT scanners is under 30 seconds for the entire body — making WBCT the fastest comprehensive diagnostic examination available in the emergency setting.

Head and Cervical Spine: Priority Assessment

Non-contrast CT of the brain is essential in any patient with altered consciousness, scalp laceration, or mechanism of injury involving deceleration. Critical findings include: extradural hematoma (biconvex hyperdense collection, typically temporal, arterial origin), subdural hematoma (crescent-shaped collection following the brain surface), subarachnoid hemorrhage (blood in the sulci and basal cisterns), cerebral contusions (heterogeneous hyperdensity in cortex, often at coup-contrecoup sites), diffuse axonal injury (punctate hemorrhages at grey-white junctions), and cerebral edema with herniation.

Cervical spine CT replaces plain radiography in major trauma due to superior sensitivity for fracture detection. All seven cervical vertebrae plus C7-T1 junction must be fully visualized. CT myelography is not routinely indicated at the primary trauma assessment.

Chest CT Findings in Trauma

CT chest in trauma detects injuries invisible on plain radiography. Key findings include: pneumothorax (including occult pneumothorax not visible on supine chest X-ray), hemothorax, rib fractures (including posterior fractures that often indicate high-energy direct trauma), pulmonary contusion and laceration (ground-glass opacity and air-filled cysts respectively), aortic injury (ranging from intimal tear to complete transection — typically at the aortic isthmus), pericardial effusion (hemopericardium in cardiac injury), and sternal and thoracic spine fractures.

Abdominal and Pelvic Organ Injury Grading

The AAST Organ Injury Scale (American Association for the Surgery of Trauma) provides standardized grading for all solid organ injuries from Grade I (minor laceration) to Grade V (shattered organ or vascular avulsion). The most commonly injured solid organs are the spleen (most common in blunt trauma), liver, and kidneys. CT findings of solid organ injury include: laceration (linear hypodense defect), contusion (ill-defined hypodensity), subcapsular hematoma (crescent of blood beneath the capsule), and active hemorrhage (hyperattenuating jet of extravasated contrast in arterial phase).

Active Hemorrhage: The Most Urgent CT Finding

Active arterial extravasation on CT appears as a focal area of high-density contrast pooling (greater than 90 HU) within or adjacent to an injured organ or vascular structure. This finding demands immediate escalation — the patient requires either emergency interventional radiology (angioembolization) or operative hemorrhage control. "Blush" of contrast that increases in size or density on delayed imaging confirms active ongoing hemorrhage. This distinction between contained hematoma and active extravasation is one of the most clinically critical dichotomies in trauma CT reporting.

Pelvic Fractures and Hemorrhage

Major pelvic ring disruptions (open-book, vertical shear, lateral compression fractures) are associated with massive retroperitoneal hemorrhage from torn pelvic venous plexuses and, less commonly, the internal iliac arteries. CT angiography demonstrating active arterial contrast extravasation in the pelvis is the trigger for urgent pelvic angiography and embolization. The radiologist must assess pelvic fracture pattern, identify the source of bleeding (arterial vs. venous), and evaluate for associated genitourinary, rectal, and neurovascular injuries in a single systematic review of the pelvic CT series.