A 32-year-old man presents to the emergency department with a stab wound to the left anterior chest. On examination, there is a single puncture wound with clean, sharp edges measuring 1.5 cm. The wound tract depth and trajectory are unclear. Which investigation is most appropriate to determine the depth of penetration and assess for underlying organ injury?

Explanation

## Investigation of Choice for Stab Wound Trajectory Assessment ### Why CT with Multiplanar Reconstruction is Optimal **Key Point:** Contrast-enhanced CT chest with multiplanar reconstruction is the gold standard for evaluating stab wounds to determine penetration depth, wound tract trajectory, and associated organ injuries without requiring invasive intervention. **High-Yield:** CT provides: - Precise depth measurement of the wound tract - Identification of trajectory through anatomical planes - Detection of pneumothorax, hemothorax, cardiac/mediastinal involvement - Assessment of solid organ (lung, liver, spleen) injury - Vascular injury detection with contrast enhancement - Non-invasive nature allows serial imaging if needed ### Clinical Pearl In hemodynamically stable patients with stab wounds to the torso, CT imaging has largely replaced mandatory exploratory surgery, reducing unnecessary laparotomies by 50–70% while maintaining safety margins. ### Comparison of Investigations | Investigation | Sensitivity | Specificity | Advantages | Limitations | |---|---|---|---|---| | **CT (multiplanar)** | 95–98% | 92–96% | Non-invasive, detailed anatomy, serial imaging possible | Radiation exposure, may miss small diaphragmatic injuries | | **Diagnostic laparoscopy** | 98–100% | 100% | Direct visualization, therapeutic capability | Invasive, requires GA, cannot assess retroperitoneal structures well | | **Chest X-ray** | 60–70% | 75–80% | Quick, available, detects pneumothorax/hemothorax | Poor soft tissue detail, misses solid organ injuries | | **Ultrasound** | 70–80% | 65–75% | Bedside, no radiation, detects free fluid | Operator-dependent, poor visualization through ribs | ### Wound Characteristics Guiding Investigation **Key Point:** Stab wounds differ from incised wounds in that the depth and trajectory are unpredictable despite a small external opening — making imaging essential. - **Penetrating depth:** Often underestimated by external appearance - **Tract angulation:** May deviate from the apparent angle of entry - **Organ involvement:** Cannot be excluded by clinical examination alone in stable patients