Active Bleeding in the Ascending Colon

An 83-year-old male with rectal bleeding. What is the diagnosis? • Xray of the Week

Figure 1. CTA abdomen/pelvis. What is the diagnosis?

Figure 2. CT angiogram: A. Non-contrast images are normal (yellow arrow) . B. Arterial phase image: Hyperdense extravasation of contrast within the lumen of the ascending colon (blue arrow), indicating active bleeding. C and D. Note the dependent layering of contrast on portal venous phase images, confirming active extravasation.

Diagnosis

Active gastrointestinal bleeding in the ascending colon.

Discussion

Gastrointestinal (GI) bleeding is a common clinical problem, particularly in the elderly, where lower GI sources predominate. Common etiologies include diverticulosis, angiodysplasia, neoplasms, ischemia, and inflammatory conditions.[1][2] In this case, the ascending colon involvement suggests a right-sided colonic source, often angiodysplasia or diverticular bleed, which can present with painless hematochezia.[3]

Active bleeding is defined as extravasation of contrast into the bowel lumen on imaging, distinguishing it from pseudo-extravasation mimics like hyperdense pills or fecal material.[4]

Imaging Findings

Multiphase computed tomography angiography (CTA) is the preferred initial imaging for hemodynamically stable patients with suspected acute GI bleeding, offering high sensitivity (85-89%) and specificity (85-95%) for detecting active extravasation.[5][6] It is rapid, widely available, and guides subsequent interventions like endoscopy or embolization.[7]

• On non-contrast phase: No extravasation; may show hyperdense sentinel clot (40-70 HU) or bowel wall abnormalities.

• On arterial phase: Active extravasation appears as hyperdense focus (>90 HU) within the lumen, often eccentric or jet-like, increasing in size or density compared to non-contrast.

• On portal venous/delayed phase: Extravasation persists or enlarges, confirming active bleed; helps differentiate from venous sources.

Reported detection rates for active bleeding exceed 0.3-0.5 mL/min, superior to nuclear medicine in many settings.[8] CTA also identifies structural causes (e.g., diverticula, tumors) even without active bleeding.[4]

Management and Prognosis

Management begins with hemodynamic resuscitation. For active lower GI bleeding confirmed on CTA, options include urgent colonoscopy (if stable), interventional radiology embolization (targeted to the bleeding vessel), or surgery for refractory cases.[1][3][7] Embolization success rates are 70-90%, with low rebleeding if superselective.[2]

Prognosis depends on bleed severity, comorbidities, and etiology; elderly patients have higher mortality (10-20% for severe bleeds). Rebleeding risk is 10-25% for diverticular sources.[6]

Key Learning Points

• Multiphase CTA is first-line for localizing active GI bleeding in stable patients, with high accuracy for extravasation.

• Look for hyperdense intraluminal contrast on post-contrast phases that is absent on non-contrast to confirm active bleed.

• CTA guides therapy by identifying the site and potential etiology; always assess for mimics like hyperdense foreign material.

• Prompt radiology interpretation is crucial to expedite embolization or endoscopy and improve outcomes.

References

1. Artigas JM, Martí M, Soto JA, Esteban H, Pinilla I, Guillén E. Multidetector CT angiography for acute gastrointestinal bleeding: technique and findings. Radiographics. 2013;33(5):1453-1470. doi:10.1148/rg.335125072

2. Wells ML, Hansel SL, Bruining DH, et al. CT for evaluation of acute gastrointestinal bleeding. Radiographics. 2018;38(4):1089-1107. doi:10.1148/rg.2018170138

3. Wortman JR, Landman W, Fulwadhva UP, Viscomi SG, Sodickson AD. CT angiography for acute gastrointestinal bleeding: what the radiologist needs to know. Br J Radiol. 2017;90(1075):20170076. doi:10.1259/bjr.20170076

4. Di Serafino M, Iacobellis F, Schillirò ML, et al. The role of CT-angiography in the acute gastrointestinal bleeding: a pictorial essay of active and obscure findings. Tomography. 2022;8(5):2369-2402. doi:10.3390/tomography8050198

5. Wu LM, Xu JR, Yin Y, Qu XH. Usefulness of CT angiography in diagnosing acute gastrointestinal bleeding: a meta-analysis. World J Gastroenterol. 2010;16(31):3957-3963. doi:10.3748/wjg.v16.i31.3957

6. García-Blázquez V, Vicente-Bártulos A, Olavarria-Delgado A, Plana MN, van der Winden D, Zamora J. Accuracy of CT angiography in the diagnosis of acute gastrointestinal bleeding: systematic review and meta-analysis. Eur Radiol. 2013;23(5):1181-1190. doi:10.1007/s00330-012-2721-x

7. Kim BS, Li BT, Engel A, Samra JS, Clarke S, Norton ID, Li AE. Diagnosis of gastrointestinal bleeding: a practical guide for clinicians. World J Gastrointest Pathophysiol. 2014;5(4):467-478. doi:10.4291/wjgp.v5.i4.467

8. Parekh PJ, Buerlein RC, Shams R, Vingan H, Johnson DA. Evaluation of gastrointestinal bleeding: update of current radiologic strategies. World J Gastrointest Pharmacol Ther. 2014;5(4):200-208. doi:10.4292/wjgpt.v5.i4.200

Kevin M. Rice, MD is the president of Global Radiology CME and is a radiologist with Cape Radiology Group. He has held several leadership positions including Board Member and Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state-of-the-art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015, Dr. Rice and Natalie Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" Award for the Most Effective Radiology Educator. He was once again a semifinalist for a "Minnie" for 2021's Most Effective Radiology Educator by AuntMinnie.com. He has continued to teach by mentoring medical students interested in radiology. Everyone he has mentored has been accepted into top programs across the country, including Harvard, UC San Diego, Northwestern, Vanderbilt, and Thomas Jefferson.

Follow Dr. Rice on Twitter @KevinRiceMD

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