Lower gastrointestinal bleeding other imaging findings
|
Lower gastrointestinal bleeding Microchapters |
|
Differentiating Lower gastrointestinal bleeding from other Diseases |
|---|
|
Diagnosis |
|
Treatment |
|
Management |
|
Surgery |
|
Case Studies |
|
Lower gastrointestinal bleeding other imaging findings On the Web |
|
American Roentgen Ray Society Images of Lower gastrointestinal bleeding other imaging findings |
|
FDA on Lower gastrointestinal bleeding other imaging findings |
|
CDC on Lower gastrointestinal bleeding other imaging findings |
|
Lower gastrointestinal bleeding other imaging findings in the news |
|
Blogs on Lower gastrointestinal bleeding other imaging findings |
|
Risk calculators and risk factors for Lower gastrointestinal bleeding other imaging findings |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Aditya Ganti M.B.B.S. [2]
Overview
Other imaging studies include radionuclide imaging that can be helpful in diagnosing lower gastrointestinal bleeding.
Other Imaging Findings
Radionuclide imaging
- Radionuclide imaging is more sensitive than angiography in detecting the source of bleeding; however, it is less specific than either a positive endoscopic or angiographic examination.[1][2][3][4]
- Rates of bleeding as little as 0.1 to 0.5 mL/min can be detected.
- Radionuclide imaging is indicated prior to angiography in patients in whom the bleeding is intermittent or has a low rate, or in whom bleeding points were not identified using CTA, or colonoscopy.
- Accuracy rates have varied across reports, and range from 24% to 91%.
Procedure
- Erythrocytes are initially labeled by intravenously injecting 2 mL of a stannous agent.
- Twenty minutes later, 400 MBq of technetium pertechnetate are injected.
- Scans are then performed every 5 minutes for up to an hour.
- Single static images are taken several hours later
Nuclear scanning agents
- Two different types of nuclear scanning agents are commonly used: technetium (99mTc) sulphur colloid, which has a short half-life, and 99mTc pertechnetate, which has a longer half-life.
- With 99mTc pertechnetate, patients can be scanned several times over a 24-hour period. Therefore the latter agent has become the favored radiotracer to use
Advantages
- Advantages common to both techniques are that they are noninvasive and have a higher sensitivity than does angiography.
Disadvantages
- The main disadvantages are that radionuclide scanning can only localize bleeding to an area of the abdomen, and the resolution does not allow the identification of a specific site in the colon.
- Anaphylactic reaction to the radioisotope
Contraindications
- Radionuclide imaging is not recommended in pregnant or breastfeeding women.
References
- ↑ Nicholson ML, Neoptolemos JP, Sharp JF, Watkin EM, Fossard DP (1989). "Localization of lower gastrointestinal bleeding using in vivo technetium-99m-labelled red blood cell scintigraphy". Br J Surg. 76 (4): 358–61. PMID 2541861.
- ↑ Flickinger FW (1981). "Location of active lower GI bleeding by technetium-99m sulfur colloid scan". J. Nucl. Med. 22 (1): 38–9. PMID 6969790.
- ↑ Hahn K, Kraus W, Eissner D (1985). "[Nuclear medical detection of hemorrhage in the gastrointestinal tract]". Dtsch. Med. Wochenschr. (in German). 110 (23): 923–4. doi:10.1055/s-2008-1068933. PMID 3873332.
- ↑ Rantis PC, Harford FJ, Wagner RH, Henkin RE (1995). "Technetium-labelled red blood cell scintigraphy: is it useful in acute lower gastrointestinal bleeding?". Int J Colorectal Dis. 10 (4): 210–5. PMID 8568406.