A 28-year-old woman is brought to the forensic medicine department for medico-legal evaluation following a stab wound to the abdomen. The wound is 1.5 cm in length with sharply demarcated edges and no tissue bridging across the wound tract. The examining doctor needs to determine whether the weapon penetrated the peritoneal cavity and assess for solid organ injury. Which investigation is most appropriate for this evaluation?

Explanation

## Investigation of Choice for Penetrating Abdominal Stab Wound ### Clinical Context A stab wound to the abdomen with clean, sharp margins requires: - Determination of peritoneal penetration - Assessment of solid organ (liver, spleen, kidney) and hollow viscus injury - Evaluation of retroperitoneal structures - Guidance for conservative vs. operative management ### Why CT Abdomen/Pelvis with Contrast is the Investigation of Choice **Key Point:** CT with IV and oral contrast is the gold-standard imaging modality for hemodynamically stable patients with penetrating abdominal trauma. **High-Yield:** CT abdomen/pelvis can: - Detect peritoneal penetration (free fluid, air, or direct organ injury) - Identify solid organ lacerations and their grade (AAST grading) - Assess for active bleeding (arterial extravasation) - Evaluate retroperitoneal hemorrhage - Detect hollow viscus perforation (free air, contrast extravasation) - Assess diaphragmatic integrity ### Comparison of Investigations | Investigation | Sensitivity | Specificity | Limitations | |---------------|-------------|-------------|-------------| | DPL | 95–98% | 85–90% | Cannot grade organ injury; invasive; blind; cannot assess retroperitoneum | | FAST | 70–85% | 90–95% | Detects only free fluid; operator-dependent; cannot grade injury; misses solid organ lacerations | | **CT with contrast** | **95–98%** | **95–98%** | Requires transport; radiation; may miss small retroperitoneal bleeds | | Diagnostic laparoscopy | 100% | 100% | Invasive; therapeutic only if injury found; risk of visceral perforation | **Clinical Pearl:** In hemodynamically stable patients (which this patient appears to be), CT is preferred because: - Non-invasive, repeatable - Grades organ injury (guides conservative vs. operative management) - Assesses all abdominal compartments including retroperitoneum - Reduces unnecessary laparotomy (selective non-operative management is safe in 50–70% of stable patients) **Mnemonic: STAB-CT** — **S**table patient, **T**rauma (penetrating), **A**bdomen; **B**est imaging is **C**T (comprehensive, **T**herapy-guiding). ### When to Use Alternative Investigations - **DPL:** Unstable patient requiring rapid decision-making (but CT preferred if transport time <10 min) - **FAST:** Rapid screening for free fluid in unstable trauma; not for grading or detailed assessment - **Laparoscopy:** Therapeutic intervention if injury confirmed; not diagnostic-only in modern practice [cite:Reddy & Rao Forensic Medicine 34e Ch 12; Sabiston Textbook of Surgery 21e Ch 20]