Musculoskeletal Imaging

What Is the Best Initial Imaging for a Normotensive Adult with Ballistic Torso Trauma?

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What Is the Best Initial Imaging for a Normotensive Adult with Ballistic Torso Trauma?

A 28-year-old male is brought into the trauma bay on a Friday night after sustaining a single gunshot wound to the torso. He is awake, alert, and his blood pressure is 118/74 mmHg. The entry wound is in the right flank, but there is no clear exit wound, making the projectile’s trajectory completely unknown. You need to rapidly assess for life-threatening internal injuries to determine if he needs immediate surgery or can be managed non-operatively. This article details the American College of Radiology (ACR) guided workflow for this specific scenario: a normotensive adult with ballistic penetrating torso trauma and an unknown trajectory. For this presentation, the initial use of a Radiography trauma series is rated Usually Appropriate.

Who Fits This Clinical Scenario?

This guidance applies to a specific subset of trauma patients. Correctly identifying your patient within this scenario is critical to applying the right imaging strategy and avoiding misdiagnosis.

Inclusion Criteria:

  • Patient: Adult
  • Mechanism: Ballistic penetrating trauma (e.g., gunshot wound, shrapnel). This implies a higher energy transfer and more unpredictable internal damage compared to stab wounds.
  • Location: Involving the torso (chest, abdomen, or pelvis).
  • Trajectory: Unknown or indeterminate. This is a key factor, as the projectile could have crossed multiple body cavities (e.g., abdomen into the chest).
  • Hemodynamics: Normotensive (stable blood pressure). This stability affords a brief window for diagnostic imaging.

Exclusion Criteria (These patients follow a different workflow):

  • Hypotensive Patients: An adult with penetrating torso trauma who is hemodynamically unstable requires a different, more urgent algorithm, often involving a FAST (Focused Assessment with Sonography for Trauma) exam and immediate surgical consultation, bypassing comprehensive imaging. This is covered in the hypotensive penetrating trauma variant.
  • Known, Limited Trajectory: If the projectile’s path is clearly confined to a single area (e.g., a superficial wound in the chest wall without crossing the midline or diaphragm), a more focused imaging protocol may be appropriate.
  • Non-Ballistic Trauma: Stab wounds or impalement injuries have different injury patterns and are addressed in separate ACR appropriateness criteria variants.

What Diagnoses Are You Working Up in This Scenario?

With an unknown ballistic trajectory through the torso, the potential for multi-system injury is high. The initial imaging workup is designed to rapidly identify or exclude a range of critical, often surgically emergent, conditions.

A primary concern is major vascular injury. High-velocity projectiles can transect or create pseudoaneurysms in the aorta, inferior vena cava, or mesenteric and renal vessels. These injuries can lead to rapid exsanguination, even in a patient who is initially normotensive.

Another immediate life-threat is injury to the thoracic contents, such as a pneumothorax or hemothorax. A projectile passing through the chest can easily violate the pleura, causing lung collapse or massive bleeding into the chest cavity. A tension pneumothorax can quickly lead to cardiovascular collapse.

The differential must also include solid organ injury. The liver, spleen, and kidneys are highly vascular and prone to severe lacerations and hemorrhage from ballistic trauma. The extent of this damage dictates whether the patient can be managed non-operatively or requires surgical intervention or interventional radiology embolization.

Finally, hollow viscus and diaphragmatic injury are significant considerations. Perforation of the bowel, stomach, or bladder can lead to peritonitis and sepsis. A tear in the diaphragm can allow abdominal contents to herniate into the chest, compromising respiratory function. These injuries can be subtle and are a key target of advanced cross-sectional imaging.

Why a Radiography Trauma Series and CT Are the Recommended Studies

For a normotensive adult with an unknown ballistic trajectory, the ACR rates three studies as Usually Appropriate: Radiography trauma series, CT chest abdomen pelvis with IV contrast, and CTA chest abdomen pelvis with IV contrast. In practice, these are often used sequentially as part of a single, streamlined workup.

The Radiography trauma series (typically AP chest and pelvis, and sometimes a lateral view) serves as the crucial first step, often performed with a portable machine in the trauma bay. Its primary roles are to:

  1. Localize Projectiles: Identifying the number and location of bullets or fragments is essential for understanding the potential trajectory and planning further imaging or surgery.
  2. Identify Gross Pathology: It can rapidly detect a large hemothorax, pneumothorax, or free air under the diaphragm, which may prompt immediate intervention (e.g., chest tube placement) even before other imaging is complete.
  3. Assess Bony Injury: Fractures of the ribs, spine, or pelvis can be identified.

Following initial radiographs, a CT of the chest, abdomen, and pelvis with intravenous (IV) contrast is almost always the definitive diagnostic study in this scenario. It provides a detailed map of the projectile’s path and comprehensively evaluates for the specific injuries in the differential diagnosis. A CTA (Computed Tomography Angiography), which uses a specific timing protocol for IV contrast to highlight arteries, is also rated Usually Appropriate and is often the preferred modality given the high risk of vascular injury. It offers superior visualization of active bleeding (contrast extravasation), pseudoaneurysms, and vessel transection.

Why are other studies rated lower for this scenario?

  • CT without IV contrast is Usually Not Appropriate. Without contrast, it is nearly impossible to evaluate for solid organ injury, differentiate blood from other fluids, or identify active vascular hemorrhage, making it diagnostically inadequate in this high-risk setting.
  • MRI is Usually Not Appropriate. It is too slow for the acute trauma setting, less available, and poses a significant safety risk due to the potential for movement and heating of metallic projectiles within the patient.

The radiation dose for a trauma series is moderate (☢☢☢ 1-10 mSv), while a comprehensive CT or CTA of the torso carries a higher dose (☢☢☢☢ 10-30 mSv or ☢☢☢☢☢ 30-100 mSv, respectively). However, in the setting of life-threatening penetrating trauma, the diagnostic benefit of identifying critical injuries far outweighs the radiation risk.

What’s Next After Initial Imaging? Downstream Workflow

The results of the initial radiographs and subsequent CT scan dictate the immediate next steps in patient management, creating a clear decision tree.

  • Positive for Major Injury: If the CT scan reveals active arterial extravasation, a large-volume hemoperitoneum with solid organ laceration, or evidence of bowel perforation, the next step is immediate consultation with trauma surgery for a potential exploratory laparotomy or thoracotomy. In cases of contained vascular injury (e.g., pseudoaneurysm) or bleeding from a specific solid organ vessel, interventional radiology may be consulted for embolization.
  • Negative or Non-operative Injury: If the CT scan shows a clear trajectory that avoids major structures, or identifies minor injuries suitable for non-operative management (e.g., a low-grade liver laceration without active bleeding), the patient can typically be admitted for observation. This involves serial abdominal exams, monitoring vital signs, and checking hemoglobin/hematocrit levels.
  • Indeterminate Findings: Occasionally, a finding may be equivocal, such as a small amount of fluid of unclear significance or a questionable area of bowel wall thickening. In these cases, the next step is often a period of close observation with a low threshold for a repeat CT scan in 6-12 hours or if the patient’s clinical status changes. The decision to proceed to surgery becomes based on the combination of imaging and evolving clinical signs like fever, tachycardia, or peritoneal signs.

Pitfalls to Avoid (and When to Get Help)

Navigating this scenario requires vigilance to avoid common diagnostic and management errors.

  • Pitfall 1: Stopping at the Radiograph. A “normal” chest and pelvis radiograph does not rule out significant injury. In ballistic trauma with an unknown trajectory, it is merely the first step; proceeding to CT is mandatory in a stable patient.
  • Pitfall 2: Forgetting Radiopaque Markers. Before any imaging, placing radiopaque markers (like taped-on paper clips) over all entry and exit wounds is crucial. This helps the radiologist and surgeon correlate the skin findings with the internal projectile path on CT.
  • Pitfall 3: Ordering a Non-Contrast CT. As noted, a non-contrast study provides insufficient information to rule out life-threatening vascular or solid organ injury and should not be ordered as the primary study in this scenario.
  • Pitfall 4: Delaying Imaging. While the patient is normotensive, they are at high risk for sudden decompensation. The imaging workup should proceed with urgency as part of the primary or secondary survey.

If the patient becomes hemodynamically unstable at any point during the workup, abandon the imaging sequence and escalate immediately to the trauma surgery team for presumed operative intervention.

Related ACR Topics and Tools

For a comprehensive overview of all clinical variants related to penetrating torso trauma, from hypotensive patients to those with stab wounds, please see our parent guide. For other tools to assist in ordering and interpreting imaging, the following resources are available.

Frequently Asked Questions

Why not go straight to a CT scan and skip the initial radiographs?

While CT is the definitive study, initial radiographs are faster, can be performed portably in the trauma bay while the team is still stabilizing the patient, and provide immediate information on projectile location and life-threatening conditions like a large pneumothorax. This information can help plan the subsequent CT and guide immediate interventions like chest tube placement.

What happens if the patient becomes hypotensive during the CT scan?

If a patient destabilizes, the imaging protocol is immediately aborted. The patient is moved from the scanner and prepared for emergent surgical intervention. The clinical scenario changes to ‘Penetrating torso trauma, hypotensive,’ where the priority shifts from diagnosis to resuscitation and operative control of hemorrhage.

Is a CTA always necessary, or is a standard CT with IV contrast sufficient?

Both are rated ‘Usually Appropriate.’ A CTA uses specific contrast timing to optimize visualization of the arterial system and is superior for detecting active bleeding or subtle vascular injuries. Given the high risk of vascular injury with ballistic trauma, many trauma centers default to a CTA protocol. A standard CT with IV contrast is still excellent for evaluating solid organs and other structures, and the choice may depend on institutional protocols and the specific clinical suspicion.

Should oral contrast be used in this scenario?

The use of oral contrast in acute trauma is controversial and generally not recommended for this specific scenario. It significantly delays the acquisition of the CT scan, can be difficult for the patient to tolerate, and may be aspirated. Modern multi-detector CT scanners with IV contrast are highly sensitive for detecting bowel injury without the need for oral contrast.

What if the bullet has crossed from the abdomen into the chest?

This is precisely why a comprehensive CT of the chest, abdomen, and pelvis is indicated when the trajectory is unknown. A trans-diaphragmatic injury is a high-risk situation, and the CT will evaluate for injuries in both cavities, such as hemothorax, pulmonary contusion, diaphragmatic rupture, and intra-abdominal organ damage, all from a single scan.

Reviewed by Pouyan Golshani, MD, Interventional Radiologist — May 30, 2026