CT Killers on Call: Algorithmic Red Flags in Abdominopelvic Emergencies

Abstract Educational poster presenting systematic CT interpretation algorithms for acute abdominal emergencies. Covers mesenteric ischemia (SMA occlusion, SMV thrombosis, NOMI), emphysematous infections (emphysematous pyelonephritis Huang staging, emphysematous cystitis, necrotising fasciitis, Fournier gangrene), bowel perforation and fistula assessment, visceral artery pseudoaneurysm risk stratification, and common mimics of bowel ischemia. Description MESENTERIC ISCHEMIA CT FINDINGS: SMA/SMV occlusion and thrombosis identification Pneumatosis intestinalis and portal venous gas as signs of bowel necrosis Non-occlusive mesenteric ischemia (NOMI) in critically ill patients Absent bowel wall enhancement as highest specificity finding CTA protocol: arterial + portal venous phases EMPHYSEMATOUS INFECTIONS CT DIAGNOSIS: Emphysematous pyelonephritis: Huang classification staging (Stage 1-4) Emphysematous cystitis: intramural vs intraluminal gas patterns Retroperitoneal necrotising fasciitis: gas tracking along fascial planes Fournier gangrene: perineal/scrotal gas, surgical emergency BOWEL PERFORATION & FISTULA CT ASSESSMENT: Pneumoperitoneum timing: post-operative (expected vs leak) vs spontaneous Crohn's disease fistula: fat halo sign, comb sign, phlegmon Gallstone ileus and Rigler's triad (pneumobilia + ectopic stone + SBO) Perforated peptic ulcer, perforated gastric carcinoma PSEUDOANEURYSM CT EVALUATION: Risk stratification by sac size: <2cm (low), 2-4cm (intermediate), >4cm (high risk) Mycotic vs non-infectious pseudoaneurysm differentiation GDA pseudoaneurysm in pancreatitis, renal artery post-biopsy Active extravasation and contained rupture signs MIMICS OF MESENTERIC ISCHEMIA: Shock bowel: hyperenhancement (NOT hypoenhancement) + collapsed IVC + small aorta Paralytic ileus: no transition point, patent vessels Infectious enteritis: mucosal hyperenhancement + comb sign Hepatic artery stenosis leading to delayed abscess KEY DIAGNOSTIC PRINCIPLE: True mesenteric ischemia = REDUCED/ABSENT bowel wall enhancement Mimics = PRESERVED/INCREASED enhancement (hyperenhancement) Target Audience Emergency radiologists, abdominal radiologists, radiology residents, emergency medicine physicians, surgeons, interventional radiologists Educational Value Systematic decision-tree algorithms for complex diagnoses CT report templates for structured reporting Risk stratification systems (Huang staging, pseudoaneurysm size criteria) Key imaging findings with sensitivity/specificity data Differential diagnosis checklists Management implications based on CT findings References Belinda De Simone (2024). The 2023 WSES guidelines on the management of trauma in elderly and frail patients. World journal of emergency surgery, 19(1). doi:https://doi.org/10.1186/s13017-024-00537-8. Bollen, T., Hazewinkel, M. and Smithuis, R. (2014). The Radiology Assistant : Acute Pancreatitis. [online] Radiologyassistant.nl. Available at: https://radiologyassistant.nl/abdomen/pancreas/acute-pancreatitis#imaging-interstitial-pancreatitis [Accessed 13 Nov. 2025]. Chingkoe, C.M., Jahed, A., Loreto, M.P., Sarrazin, J., McGregor, C.T., Blaichman, J.I. and Glanc, P. (2015). Retroperitoneal Fasciitis: Spectrum of CT Findings in the Abdomen and Pelvis. RadioGraphics, 35(4), pp.1095–1107. doi:https://doi.org/10.1148/rg.2015140071. Gore, R. and Smithuis, R. (2015). The Radiology Assistant : CT-pattern of Bowel wall thickening. [online] radiologyassistant.nl. Available at: https://radiologyassistant.nl/abdomen/bowel/bowel-wall-thickening-ct-pattern [Accessed 7 Nov. 2025]. Panda, A., Kayali, M. and Aswani, Y. (2025). Emphysematous conditions of the abdomen and pelvis: pearls and pitfalls. Abdominal Radiology. doi:https://doi.org/10.1007/s00261-025-04997-7. Sherchan, R. and Hamill, R. (2024). [Table], Table. Huang and Tseng Classification of EPN. [online] Nih.gov. Available at: https://www.ncbi.nlm.nih.gov/books/NBK599505/table/article-155434.table0/ [Accessed 15 Nov. 2025]. Soltani, T. and Jurkovich, G.J. (2025). Diagnosis and management of pancreatic trauma: What you need to know. Journal of Trauma and Acute Care Surgery. doi:https://doi.org/10.1097/ta.0000000000004523.