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

Yield of CT Angiography and Contrast-Enhanced MR Imaging in Patients with Dizziness

This is a retrospective analysis of all CTAs, CE MRAs, and CE IAC studies acquired in patients with  "dizziness" or "vertigo" performed between January 2011 and June 2012. Patients that had focal neurologic findings specified on the requestion or in the history on the EMR were excluded (clinical findings such as vomiting, focal weakness, aphasia, and vision loss). Also patients with prior history of a posterior mass, an underlying inflammatory condition or vascular abnormalities were excluded from the study.  

A total of 798 studies were included (228 CTAs, 304 CE MR, and 266 CE IAC MR).  The age range was 6-93 years.  32% of the studies were performed in the ER setting.  Only 1.6 % of cases had a diagnostic efficacy* and 1.0% had a therapeutic efficacy**.  There was no statistical significance difference between the modalities or the ordering specialty (ie. ER, ENT or primary care).  

*Diagnostic Efficacy: defined by the ACR as the number of studies with a new or progressive major finding divided by the total number of studies.

**Therapeutic Efficacy: defined by the ACR as the number of studies resulting in a change in clinical management divided by the total number of studies

Population: All patients presenting to the ER, primary care physician, or otolaryngologist (including the pediatric population) with isolated dizziness or "vertigo".  Patients with a known posterior fossa mass, underlying inflammatory conditions (such as MS), or vascular abnormalities were excluded.   The age range in the study was 6-93.

Intervention: Utility of CTA, CE MR and/or CE IAC MR in the above stated patient population

Comparison: N/A

Outcome: The diagnostic and therapeutic efficacy of CTA, CE MR, and CE IAC MR for patients presenting with isolated dizziness is reported to be 1.6% and 1.0% respectively. 

Links: Pubmed, Original article 

Fakhran S et al (2013).  American Journal of Neuroradiology. 34:1077-81