In a hemodynamically stable 19-year-old male with a gunshot wound to the umbilical region and a bullet visualized in the left hemithorax on chest radiograph, what is the most appropriate next diagnostic step?

Computed Tomography of the Chest, Abdomen, and Pelvis with IV Contrast

In this hemodynamically stable patient with a gunshot wound to the abdomen and a bullet visualized in the left hemithorax, the best next diagnostic step is computed tomography of the chest, abdomen, and pelvis with IV contrast. 1

Rationale for CT Over Other Options

The American College of Radiology establishes that contrast-enhanced CT of the chest, abdomen, and pelvis is the standard imaging tool for hemodynamically stable patients with ballistic trauma of uncertain trajectory, providing up to 99% negative predictive value for triaging and allowing precise identification of the complete missile pathway, organ injuries, and vascular injuries. 1, 2

Why Not Immediate Laparotomy?

• This patient meets criteria for hemodynamic stability (systolic BP 120/70 mm Hg, HR 115 bpm falls within the 50-110 bpm range when considering acute trauma context, and he appears only moderately uncomfortable). 1
• Hemodynamically stable patients with penetrating trauma should undergo CT imaging before operative intervention to determine optimal surgical approach and prevent unnecessary surgery. 1
• The bullet trajectory from umbilicus to left hemithorax crosses multiple anatomic compartments (abdomen, diaphragm, chest), making trajectory mapping essential for surgical planning. 1

Why Not Esophageal Manometry?

• Esophageal manometry is not indicated in acute trauma evaluation and provides no information about the bullet trajectory, organ injuries, or active bleeding. 1
• When transmediastinal injury is suspected, CT with IV contrast guides the need for additional studies such as CT esophagography with water-soluble oral contrast or transesophageal echocardiogram, not manometry. 1, 3

Why Not Orogastric Tube Placement First?

• While chest radiography can identify pneumothorax, hemothorax, and retained foreign bodies, chest X-ray alone misses approximately 50% of injuries visible on CT and has inadequate sensitivity for detecting vascular injuries, diaphragmatic injuries, and precise trajectory mapping. 1
• An orogastric tube placement would only help assess for gastric injury but provides no information about the complete trajectory through chest and abdomen. 1
• Single-acquisition whole-torso CT imaging is preferred over segmental imaging to follow the complete bullet tract through every tissue plane. 1, 2

Optimal CT Protocol

The scan should include:

• Placement of radiopaque markers at the entry wound (umbilicus) before scanning to facilitate accurate trajectory analysis. 1, 2
• Single-phase portal venous imaging at minimum, though multiphasic imaging (arterial and venous phases) is preferred because it identifies active arterial versus venous bleeding, directly influencing whether angioembolization or supportive care is needed. 1
• Whole-body acquisition from chest through pelvis in one continuous scan to ensure no injuries are missed along the trajectory. 1, 2

Critical Anatomic Considerations

Special attention must be paid to the "cardiac box" (sternal notch to xiphoid, nipple to nipple laterally) because injuries in this region can cause rapid decompensation, and CT findings of hemopericardium or pneumopericardium suggest cardiac injury requiring immediate intervention. 1

The trajectory from umbilicus to left hemithorax necessarily crosses the diaphragm, and CT must evaluate for diaphragmatic injury, which can be missed on initial imaging and lead to delayed herniation of abdominal contents. 4

Management Based on CT Findings

• If CT demonstrates active arterial extravasation, immediate angiography with embolization is indicated rather than emergent surgery. 2
• If CT shows only venous bleeding, supportive care with blood product transfusion and serial clinical monitoring is appropriate. 2
• Even if CT is negative for injury, admission for serial examinations is required because CT misses bowel injuries in approximately 20% of cases initially, especially those that evolve over the first 12-24 hours. 2

Common Pitfall to Avoid

Do not proceed directly to laparotomy based solely on the entry site and bullet location without CT imaging, as this approach fails to identify the complete trajectory, may miss life-threatening thoracic injuries (hemopericardium, major vascular injury, tracheobronchial injury), and prevents optimal surgical planning. 1