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Localizing Acute Lower Gastrointestinal Hemorrhage: CT Angiography Versus Tagged RBC Scintigraphy
Joseph D Feuerstein1, Gyanprakash Ketwaroo1, Sumeet K Tewani1
11 Department of Medicine, Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, 110 Francis St, 8E, Boston, MA 02215.
Insights
CT angiography (CTA) and RBC scintigraphy both detect active lower gastrointestinal bleeding (LGIB). CTA offers significantly better localization of the bleeding site compared to RBC scintigraphy.
Area of Science:
- Gastroenterology
- Radiology
- Medical Imaging
Background:
- Lower gastrointestinal hemorrhage (LGIB) is a frequent cause of hospitalization, leading to significant morbidity and costs.
- CT angiography (CTA) is an emerging alternative to technetium-99m-labeled red blood cell scintigraphy (RBC scintigraphy) for LGIB localization.
- Comparative efficacy data between CTA and RBC scintigraphy for LGIB are limited.
Purpose of the Study:
- To evaluate the diagnostic utility of CTA compared to RBC scintigraphy.
- To assess the effectiveness of CTA and RBC scintigraphy in the management of acute LGIB.
- To compare the accuracy of bleeding site localization between CTA and RBC scintigraphy.
Main Methods:
- Retrospective review of 45 CT angiography (CTA) examinations for suspected acute LGIB.
- Comparison with 90 RBC scintigraphic scans obtained for the same indication.
- Assessment of accurate localization of the bleeding site and source for both imaging modalities.
Main Results:
- Active gastrointestinal bleeding was identified in 38% of both CTA and RBC scintigraphy scans.
- Accurate localization of the bleeding site was achieved in 53% of CTA scans.
- This localization rate for CTA was significantly higher than the 30% rate for RBC scintigraphy (p = 0.008).
- No significant differences were observed in hospital stay, transfusion needs, acute kidney injury, or mortality.
Conclusions:
- Both CTA and RBC scintigraphy are effective in identifying active bleeding in LGIB cases.
- CTA demonstrates a significantly higher rate of accurate bleeding site localization compared to RBC scintigraphy.
- CTA may offer advantages in the management of acute lower gastrointestinal bleeding due to improved localization.
Objective:
Lower gastrointestinal hemorrhage is a common cause of hospitalization and has substantial associated morbidity and financial cost. CT angiography (CTA) is emerging as an alternative to (99m)Tc-labeled RBC scintigraphy (RBC scintigraphy) for the localization of acute lower gastrointestinal bleeding (LGIB); however, data on comparative efficacy are scant. The aim of this study was to assess the utility of CTA compared with RBC scintigraphy in the overall evaluation and management of acute LGIB.
Materials And Methods:
We retrospectively reviewed images from all CTA examinations performed for suspected acute LGIB at our tertiary care hospital from January 2010 through November 2011. The comparison group was determined by retrospective review of twice the number of RBC scintigraphic scans consecutively obtained from June 2008 to November 2011 for the same indication. All CTA and RBC scintigraphic scans were reviewed for accurate localization of the site and source of suspected active LGIB.
Results:
In total, 45 CTA and 90 RBC scintigraphic examinations were performed during the study period. Seventeen (38%) CTA scans showed active gastrointestinal bleeding compared with 34 (38%) RBC scintigraphic scans (p = 1.000). However, the site of bleeding was accurately localized on 24 (53%) CTA scans. This proportion was significantly greater than the proportion localized on RBC scintigraphic scans (27 [30%]) (p = 0.008). There were no significant differences between the two groups in average hospital length of stay, blood transfusion requirement, incidence of acute kidney injury, or in-hospital mortality.
Conclusion:
Both CTA and RBC scintigraphy can be used to identify active bleeding in 38% of cases. However, the site of bleeding is localized with CTA in a significantly higher proportion of studies.
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