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{{CMG}} ; {{AE}} {{ADG}} | {{CMG}} ; {{AE}} {{ADG}} | ||
==Overview== | ==Overview== | ||
Other imaging studies include radionuclide imaging that can be helpful in diagnosing lower gastrointestinal bleeding. | Other imaging studies include [[radionuclide imaging]] that can be helpful in diagnosing lower gastrointestinal bleeding. | ||
==Other Imaging Findings== | ==Other Imaging Findings== | ||
===Radionuclide imaging=== | ===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. | *[[Radionuclide imaging]] is more sensitive than [[angiography]] in detecting the source of [[bleeding]]; however, it is less specific than either a positive [[endoscopic]] or [[Angiogram|angiographic]] examination.<ref name="pmid2541861">{{cite journal |vauthors=Nicholson ML, Neoptolemos JP, Sharp JF, Watkin EM, Fossard DP |title=Localization of lower gastrointestinal bleeding using in vivo technetium-99m-labelled red blood cell scintigraphy |journal=Br J Surg |volume=76 |issue=4 |pages=358–61 |year=1989 |pmid=2541861 |doi= |url=}}</ref><ref name="pmid6969790">{{cite journal |vauthors=Flickinger FW |title=Location of active lower GI bleeding by technetium-99m sulfur colloid scan |journal=J. Nucl. Med. |volume=22 |issue=1 |pages=38–9 |year=1981 |pmid=6969790 |doi= |url=}}</ref><ref name="pmid3873332">{{cite journal |vauthors=Hahn K, Kraus W, Eissner D |title=[Nuclear medical detection of hemorrhage in the gastrointestinal tract] |language=German |journal=Dtsch. Med. Wochenschr. |volume=110 |issue=23 |pages=923–4 |year=1985 |pmid=3873332 |doi=10.1055/s-2008-1068933 |url=}}</ref><ref name="pmid8568406">{{cite journal |vauthors=Rantis PC, Harford FJ, Wagner RH, Henkin RE |title=Technetium-labelled red blood cell scintigraphy: is it useful in acute lower gastrointestinal bleeding? |journal=Int J Colorectal Dis |volume=10 |issue=4 |pages=210–5 |year=1995 |pmid=8568406 |doi= |url=}}</ref> | ||
*Rates of bleeding as little as 0.1 to 0.5 mL/min can be detected. | *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 | *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%. | *Accuracy rates have varied across reports, and range from 24% to 91%. | ||
====Procedure==== | ====Procedure==== | ||
*Erythrocytes are initially labeled by intravenously injecting 2 mL of a stannous agent. | *[[Erythrocytes]] are initially labeled by [[intravenously]] injecting 2 mL of a [[Stannous fluoride|stannous agent]]. | ||
*Twenty minutes later, 400 MBq of technetium pertechnetate are injected. | *Twenty minutes later, 400 MBq of [[Technetium-99m|technetium pertechnetate]] are injected. | ||
*Scans are then performed every 5 minutes for up to an hour. | *Scans are then performed every 5 minutes for up to an hour. | ||
*Single static images are taken several hours later | *Single static images are taken several hours later | ||
====Nuclear scanning agents==== | ====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. | *Two different types of nuclear scanning agents are commonly used: [[Technetium (99mTc) exametazime|technetium (99mTc) sulphur colloid]], which has a short half-life, and [[Pertechnetate|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 | *With [[Pertechnetate|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==== | ||
*Advantages common to both techniques are that they are noninvasive and have a higher sensitivity than does angiography. | *Advantages common to both techniques are that they are [[noninvasive]] and have a higher [[sensitivity]] than does [[angiography]]. | ||
====Disadvantages==== | ====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. | *The main disadvantages are that [[Radionuclide imaging|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 | *[[Anaphylactic reaction]] to the radioisotope | ||
====Contraindications==== | ====Contraindications==== | ||
*Radionuclide imaging is not recommended in pregnant or breastfeeding women. | *[[Radionuclide imaging]] is not recommended in [[pregnant]] or [[Breastfeeding|breastfeeding women]]. | ||
==References== | ==References== | ||
{{Reflist|2}} | {{Reflist|2}} | ||
Latest revision as of 20:32, 14 December 2017
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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.