Emergency and Trauma · Polytrauma

Polytrauma and Whole-Body CT One-Liners

High-yield one-liners on polytrauma imaging strategy, whole-body CT protocols, eFAST and key injury patterns encountered in emergency trauma radiology.

Rapid-revision one-liners covering polytrauma imaging strategy, whole-body CT acquisition, focused ultrasound and critical injury recognition for emergency trauma reporting.

Primary survey imaging
ATLS primary survey imaging includes portable chest radiograph, anteroposterior pelvis radiograph and eFAST ultrasound; these are performed in the resuscitation room before definitive CT.
Whole-body CT indication
Whole-body CT (WBCT) is indicated in polytrauma with haemodynamic instability of uncertain cause, high-energy mechanism, multiple body-region injuries or when clinical examination is unreliable.
WBCT acquisition strategy
Typical WBCT protocol: non-contrast head, contrast-enhanced neck-to-pelvis in portal venous phase (70-80 seconds), with optional arterial phase for suspected vascular injury; total acquisition under 30 seconds.
eFAST windows
eFAST evaluates four regions: right upper quadrant (Morison pouch), left upper quadrant (splenorenal), pelvis (pouch of Douglas or rectovesical) and pericardium; bilateral anterior thoracic views assess pneumothorax.
eFAST pneumothorax sign
Absence of lung sliding with M-mode showing barcode sign (instead of seashore sign) indicates pneumothorax; lung point sign is specific for pneumothorax.
Haemothorax on supine radiograph
On a supine chest radiograph, haemothorax layers posteriorly and may appear only as a diffuse haze over the hemithorax; 500 mL of blood may be missed on supine films.
Cervical spine CT in trauma
CT is the primary imaging modality for cervical spine assessment in polytrauma; NEXUS or Canadian C-spine rules guide imaging in alert patients, but obtunded polytrauma patients warrant CT.
Blunt thoracic aortic injury
Blunt aortic injury most commonly occurs at the aortic isthmus just distal to the left subclavian artery; CT angiography is the investigation of choice with sensitivity exceeding 95%.
Splenic injury grading
AAST splenic injury grading (I-V) is based on CT findings: subcapsular haematoma size, laceration depth and active extravasation; grade IV-V injuries or haemodynamic instability warrant intervention.
Hepatic injury CT signs
Key CT findings include laceration (linear low-attenuation), subcapsular haematoma, parenchymal contusion and active contrast extravasation; active blush indicates ongoing haemorrhage requiring embolisation or surgery.
Renal injury classification
AAST renal injury grading: grade I (contusion/subcapsular haematoma) to grade V (shattered kidney or pedicle avulsion); CT with delayed excretory phase detects collecting system injuries.
Pelvic fracture and haemorrhage
Open-book pelvic fractures (APC type) disrupt the posterior venous plexus causing life-threatening haemorrhage; CT angiography identifies arterial bleeding amenable to embolisation.
Mesenteric and bowel injury
CT signs include free fluid without solid-organ injury, mesenteric fat stranding, bowel wall thickening, extraluminal air or contrast; seatbelt sign on abdominal wall raises suspicion.
Diaphragmatic rupture
Left-sided diaphragmatic rupture is more common (75%); CT signs include diaphragmatic discontinuity, collar sign, dependent viscera sign and hump-and-band sign.
Blunt cerebrovascular injury
BCVI (carotid or vertebral dissection) should be suspected with cervical spine fractures, Le Fort II/III fractures or base-of-skull fractures involving the carotid canal; CT angiography is the screening tool.
Fat embolism syndrome
Fat embolism typically presents 24-72 hours after long-bone fractures with respiratory distress, neurological symptoms and petechial rash; CT shows diffuse ground-glass opacities and centrilobular nodules.
Pneumoperitoneum in trauma
Free intraperitoneal air on CT after blunt trauma indicates hollow viscus perforation until proven otherwise; even small volumes warrant surgical consultation.
Contrast extravasation significance
Active contrast extravasation (jet or blush) on arterial or portal venous phase CT indicates ongoing haemorrhage and is the key finding directing angioembolisation or surgical intervention.
Delayed imaging in trauma
Delayed-phase CT (5-10 minutes) is essential for detecting renal collecting system injuries, ureteric disruption and subtle bladder perforation not seen on portal venous phase.
Reporting priority in polytrauma
Report life-threatening findings first: active haemorrhage, tension pneumothorax, aortic injury, herniation and expanding haematoma; use structured body-region reporting to avoid omissions.

Caution

Trauma CT protocols vary by institution, scanner capability and clinical pathway. Haemodynamic status always dictates whether the patient proceeds to CT or directly to the operating theatre or interventional suite.

Exam pearl

In viva, always state the mechanism and haemodynamic status before interpreting findings. Active extravasation on CT is the single most management-changing finding in blunt solid-organ trauma.

Viva questions

What are the four windows of the eFAST examination?
Right upper quadrant (Morison pouch), left upper quadrant (splenorenal recess), pelvis (pouch of Douglas or rectovesical pouch) and subxiphoid pericardial view. Bilateral anterior chest views are added for pneumothorax assessment.
Where does blunt thoracic aortic injury most commonly occur?
At the aortic isthmus, just distal to the left subclavian artery, where the mobile aortic arch meets the fixed descending aorta anchored by the ligamentum arteriosum.
What CT finding in blunt solid-organ trauma most directly indicates the need for angioembolisation?
Active contrast extravasation (contrast jet or blush) on arterial or portal venous phase CT, indicating ongoing haemorrhage that is unlikely to tamponade spontaneously.
Why is delayed-phase CT important in renal trauma?
Delayed imaging at 5-10 minutes allows excretion of contrast into the collecting system, enabling detection of collecting system laceration, ureteric injury or urinoma that may not be visible on portal venous phase alone.
What is the barcode sign on lung ultrasound?
On M-mode, absence of lung sliding produces parallel horizontal lines (barcode or stratosphere sign) instead of the normal granular seashore pattern, indicating pneumothorax. The lung point sign, where normal sliding intermittently returns, is specific for pneumothorax.

Sources