Acute lower intestinal bleeding: Feasibility and diagnostic performance of CT angiography

Prospective study to assess the diagnostic performance of CT Angiography (CTA) as the initial exam for all patients in ER with acute LGIB.  

Prospective, single center, N= 47 (mean age 68)

All patients underwent CTA first before continuing reference standard (c-scope, angio or laparotomy). 

Triphasic 64 slice MDCT scan of the abdomen and pelvis with IV contrast, no oral contrast. 

2 Radiologists scored for: Active extravasation (spot or jet) on art or pvp. High attenuation (>60hu) on c-. Possible cause of bleed. 

Results: 

Of the 47 pts, 19 had bleed by reference standard, 28 no bleed. Results for identifying bleed SENS 100% SPEC  96% (PPV 95%, NPV 100%).  Accuracy 93% for the cause of bleed in 44/47. 

Limitations: 

No description of severity of bleed or patient’s clinical status before inclusion

No control group

Standard of reference was a not a single gold standard test

Unclear if surgeons and IR were blinded to CTA results

No follow up of patient outcome

No discussion of time to CTA or intervention

PICO Analysis:
Population:

• Inclusion criteria: Acute LGIB defined by hematochezia, or melena. Indication for emergent colonoscopy, angiography, or laparotomy as determined by ER MD.
• Exclusion criteria: Concomitant upper GI bleed. Contraindication to IV contrast. Creatinine greater than 200 mg/L. Pregnancy.

Intervention: Triphasic CT angiogram
Comparison: Catheter angiography, Colonoscopy or Laparotomy.
Outcome: Sensitivity 100%, Specificity 96%.

Reference: Martí M et al. Radiology. 2012 Jan; 262(1):109-16. 
Links: Pubmed, Full Text