Musculoskeletal Imaging

What Imaging Should You Order for a Stable Adult with a Nonballistic Abdominal Penetrating Injury?

May 29, 2026 · Pouyan Golshani, MD, Interventional Radiologist

A 34-year-old male is brought into the emergency department after an assault, sustaining a single stab wound to his right upper quadrant. He is alert, his vitals are stable, and he is hemodynamically normotensive. While the trauma team performs their primary survey, you consider the next steps for evaluation. The external wound is small, but the depth and trajectory are unknown. You need to decide on the most appropriate initial imaging study to assess for internal injury without delaying potential intervention. This article provides a detailed workflow for this specific scenario, guided by the American College of Radiology (ACR) Appropriateness Criteria, which rate a ‘Radiography trauma series’ as Usually Appropriate for this presentation.

Who Fits This Clinical Scenario?

This guidance applies to a specific subset of trauma patients. The key inclusion criteria are:

Adult Patient: The patient is skeletally mature.
Nonballistic Penetrating Trauma: The injury is from a stabbing, impalement, or similar mechanism, not a gunshot wound.
Limited to Abdomen and Pelvis: The entry wound and suspected trajectory are confined below the diaphragm.
Normotensive: The patient is hemodynamically stable, without hypotension requiring significant resuscitation.

It is critical to distinguish this presentation from similar but distinct clinical scenarios that require a different diagnostic approach. This workflow does not apply if the patient is:

Hypotensive: A patient with penetrating torso trauma and hypotension is critically unstable and may require immediate surgical exploration, often bypassing comprehensive imaging. This is a separate ACR variant.
A Victim of Ballistic Trauma: Gunshot wounds involve significantly higher energy transfer and unpredictable trajectories, necessitating a different imaging protocol.
Sustaining an Injury with an Unknown Trajectory: If the wound could potentially involve both the chest and abdomen (e.g., a wound near the diaphragm), imaging of both cavities is typically required.

What Diagnoses Are You Working Up in This Scenario?

In a normotensive patient with a nonballistic penetrating injury to the abdomen, the primary goal of imaging is to rule out injuries that require surgical or interventional radiology management. The differential diagnosis is focused on identifying specific, consequential injuries.

Peritoneal Violation: The most fundamental question is whether the penetrating object has breached the peritoneal cavity. A violation significantly increases the risk of intra-abdominal injury and often changes management from simple wound care and observation to more aggressive evaluation or intervention.

Hollow Viscus Injury: Injury to the stomach, small bowel, or colon is a major concern. A perforation can lead to pneumoperitoneum (free air) and subsequent peritonitis and sepsis. While free air is a specific sign, it is not always present, and other signs of bowel injury (e.g., wall thickening, mesenteric stranding) must be sought on cross-sectional imaging.

Solid Organ Injury: The liver, spleen, and kidneys are frequently injured depending on the wound location. Imaging aims to identify lacerations, hematomas, or signs of active arterial extravasation. The stability of the patient makes it possible to detect and potentially manage many of these injuries non-operatively or with angioembolization.

Vascular or Mesenteric Injury: Though less common in stable patients, injury to major vessels (e.g., aorta, vena cava, iliac vessels) or their mesenteric branches can occur. Signs include active bleeding, pseudoaneurysm formation, or hematoma, which are best visualized with intravenous contrast.

Why Is a Radiography Trauma Series or CT Scan the Recommended Approach?

For a normotensive adult with a nonballistic penetrating injury limited to the abdomen and pelvis, the ACR rates both Radiography trauma series and CT abdomen and pelvis with IV contrast as Usually Appropriate. The choice and sequence depend on clinical judgment and institutional protocols, but both play a key role.

A Radiography trauma series (adult relative radiation level ☢☢☢ 1-10 mSv) often includes an upright chest radiograph to look for pneumoperitoneum under the diaphragm, which is a highly specific sign of a perforated hollow viscus. It can also identify retained foreign bodies (e.g., a broken knife tip). It is fast, widely available, and can provide immediate, actionable information that may direct a patient straight to the operating room.

However, radiography has significant limitations. It cannot evaluate solid organs, assess for active bleeding, or detect subtle signs of bowel or mesenteric injury. Therefore, in most cases, a negative or non-diagnostic radiograph in a patient with a concerning mechanism will be followed by a more definitive study.

This definitive study is typically a CT abdomen and pelvis with IV contrast (adult RRL ☢☢☢ 1-10 mSv). This modality is highly sensitive and specific for the entire differential diagnosis, including solid organ lacerations, hematomas, active vascular extravasation, bowel wall injury, and retroperitoneal injuries. The use of intravenous contrast is crucial for identifying vascular injuries and improving the conspicuity of organ damage.

Why Alternatives Are Rated Lower

CT abdomen and pelvis without IV contrast is rated May be appropriate. While it can detect large hematomas, free air, and some organ injuries, it is insensitive for active bleeding and subtle organ parenchymal or bowel wall injuries, which are the primary concerns in this scenario.
MRI abdomen and pelvis is rated Usually not appropriate. MRI is time-consuming, less available in an emergency setting, and highly susceptible to motion artifact in a trauma patient. It offers no significant advantage over CT for the acute injuries being evaluated.

What’s Next After Initial Imaging? Downstream Workflow

The results of the initial imaging study will guide the subsequent clinical pathway. The decision tree often branches based on specific positive or negative findings.

Positive for Pneumoperitoneum or Evisceration: If initial radiography or clinical exam reveals free intraperitoneal air or evisceration of abdominal contents, this typically indicates a need for immediate surgical consultation for exploratory laparotomy.
Positive CT Scan (Specific Injury Identified): If the CT scan shows a solid organ injury, active bleeding, or significant bowel/mesenteric injury, management is dictated by the finding. An unstable bleed may require interventional radiology for embolization or surgery. A significant bowel injury requires surgical repair. A contained, non-bleeding solid organ injury may be managed with observation and serial exams.
Negative CT Scan: If a high-quality CT with IV contrast is negative for any intra-abdominal injury, the patient may be managed with a period of observation, serial abdominal exams, and local wound care. A negative CT scan has a very high negative predictive value for clinically significant injuries that would require operative intervention.
Indeterminate Findings: In rare cases where findings are equivocal (e.g., focal bowel wall thickening without clear perforation), a period of close observation with serial clinical examinations is warranted. A repeat CT scan may be considered if the patient’s clinical status changes or fails to improve.

Pitfalls to Avoid (and When to Get Help)

Several common pitfalls can complicate the evaluation of these patients. First, do not underestimate the potential for serious injury based on a small external wound; the internal damage can be extensive. Second, relying solely on a negative trauma radiograph to rule out significant injury is a frequent error; in a patient with a concerning mechanism, a negative x-ray should prompt progression to CT. Third, omitting intravenous contrast on the CT scan severely limits its diagnostic utility for vascular and solid organ injuries. Finally, failing to perform serial abdominal exams, even after a negative CT, can lead to a missed diagnosis of a delayed-onset bowel injury. If the patient develops worsening pain, fever, or hemodynamic instability at any point, escalate immediately for a surgical consultation, regardless of initial imaging findings.

Frequently Asked Questions

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

Many trauma centers do go directly to CT for stable patients with penetrating abdominal trauma, as it is the most comprehensive test. However, an upright chest radiograph is extremely fast and can sometimes provide a definitive diagnosis (pneumoperitoneum) that sends a patient to the OR faster than a CT can be completed. The ACR rates both as ‘Usually Appropriate’, reflecting that either approach is acceptable and often depends on institutional workflow and the specifics of the patient’s presentation.

Does the location of the stab wound (e.g., flank vs. anterior abdomen) change the imaging choice?

Yes, the location is critical. While the initial imaging study (CT with IV contrast) remains the same, the location raises suspicion for specific injuries. A flank or back wound increases concern for retroperitoneal injuries, including to the kidneys, ureters, and major vessels. In these cases, a delayed excretory phase on the CT (‘triple-phase’ or ‘CT urogram’) may be added to evaluate for urinary tract injury.

Is oral contrast necessary for evaluating bowel injury in this scenario?

The use of oral contrast in acute abdominal trauma is controversial and generally not recommended by the ACR for this scenario. Administering oral contrast takes a significant amount of time (often over an hour), which can unacceptably delay diagnosis. Modern multidetector CT scanners with IV contrast are highly sensitive for detecting indirect signs of bowel injury, such as wall thickening, abnormal enhancement, and mesenteric stranding, making oral contrast largely unnecessary in the acute setting.

What defines ‘normotensive’ in this context, and when does a patient become too unstable for CT?

‘Normotensive’ generally refers to a patient with a systolic blood pressure consistently above 90-100 mm Hg who is not requiring ongoing fluid or blood product resuscitation to maintain that pressure. A patient is considered too unstable for CT if they have ‘transient’ or ‘no’ response to initial resuscitation, meaning their blood pressure remains low or drops again after a fluid bolus. These patients often require immediate transfer to the operating room for surgical control of hemorrhage.

If the patient has a stab wound to the lower abdomen or pelvis, should the CT protocol be different?

For penetrating trauma to the lower abdomen and pelvis, the standard CT abdomen and pelvis with IV contrast is appropriate. However, the radiologist and clinical team should have a heightened suspicion for bladder and ureteral injury. If there is gross hematuria, a CT cystogram (instilling contrast directly into the bladder via a Foley catheter) may be performed after the initial scan to definitively rule out a bladder rupture.

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