Role of Multidetector Computed Tomography Angiographyin Acute Gastro Intestinal Tract Bleeding
Doaa Abdelaziz Abdelsalam Anany;
Abstract
SUMMARY AND CONCLUSION
A
cute GIB is a serious and often life-threatening condition. It is typically categorized as either upper or lower depending on the anatomic location of the bleeding site.
Upper gastrointestinal bleeding (UGIB) may involve the esophagus, stomach, and duodenum. It carries a mortality rate of approximately 10%. Its common causes in order of frequency are: Erosions or ulcers, variceal bleeding, Mallory-Weiss tear, vascular lesions, and neoplasms.
Lower gastrointestinal bleeding (LGIB) may involve the small bowel, colon, and rectum. It is less common than UGIB and accounts for approximately 30% of all GIB. It carries a mortality rate of 3.6%. Its common causes in order of frequency are: Diverticular disease, angiodysplasia, neoplasms, colitis, and benign anorectal lesions.
Available diagnostic procedures are either of low diagnostic accuracy such as barium examinations and scintigraphy, invasivesuch as catheter angiography or insensitive in localizing small bowel lesions such as endoscopy and capsule endoscopy.
The introduction of multi-detector CT has markedly reduced acquisition times, and this minimizes image degradation from movement artifact caused by peristalsis or respiration, thus all vascular territories can be imaged simultaneously during the contrast bolus.
There are two features were considered diagnostic of acute GIB: first, presence of extravasation of CM into the bowel lumen that progressed from one phase to the other, being present in the arterial but not in the native phase, or that progressed from the arterial to the portal venous phase, and second, extravasated CM with attenuation levels greater than 90 HU.
The extravasated CM is seen within the bowel lumen in form of linear, jet like, swirled, ellipsoid, or pooled configurations or may fill the entire bowel lumen, resulting in a hyperattenuating loop through comparing sequentially acquired unenhanced CT scans and CT angiograms without rigid adherence to attenuation analysis.
Two other minor but useful CT findings suggestive of acute massive GIB are focal dilatation of fluid-filled bowel segment noted on contrast enhanced CT scan and acute hematoma on unenhanced CT scan.
Evaluation of GIB with CTA may provide concurrent localization of active hemorrhage and diagnosis of the underlying cause, and can also have important treatment and management implications, as it provides high quality thin section data with postprocessing techniques as MPR, CPR, MIP, SR, VR, and endoluminal imaging which lead to accurate localization of the anatomical site of bleeding, as well as depicting the specific bleeding vessel, leading to rapid targeted embolization without the need for preliminary angiography of all territories.
A
cute GIB is a serious and often life-threatening condition. It is typically categorized as either upper or lower depending on the anatomic location of the bleeding site.
Upper gastrointestinal bleeding (UGIB) may involve the esophagus, stomach, and duodenum. It carries a mortality rate of approximately 10%. Its common causes in order of frequency are: Erosions or ulcers, variceal bleeding, Mallory-Weiss tear, vascular lesions, and neoplasms.
Lower gastrointestinal bleeding (LGIB) may involve the small bowel, colon, and rectum. It is less common than UGIB and accounts for approximately 30% of all GIB. It carries a mortality rate of 3.6%. Its common causes in order of frequency are: Diverticular disease, angiodysplasia, neoplasms, colitis, and benign anorectal lesions.
Available diagnostic procedures are either of low diagnostic accuracy such as barium examinations and scintigraphy, invasivesuch as catheter angiography or insensitive in localizing small bowel lesions such as endoscopy and capsule endoscopy.
The introduction of multi-detector CT has markedly reduced acquisition times, and this minimizes image degradation from movement artifact caused by peristalsis or respiration, thus all vascular territories can be imaged simultaneously during the contrast bolus.
There are two features were considered diagnostic of acute GIB: first, presence of extravasation of CM into the bowel lumen that progressed from one phase to the other, being present in the arterial but not in the native phase, or that progressed from the arterial to the portal venous phase, and second, extravasated CM with attenuation levels greater than 90 HU.
The extravasated CM is seen within the bowel lumen in form of linear, jet like, swirled, ellipsoid, or pooled configurations or may fill the entire bowel lumen, resulting in a hyperattenuating loop through comparing sequentially acquired unenhanced CT scans and CT angiograms without rigid adherence to attenuation analysis.
Two other minor but useful CT findings suggestive of acute massive GIB are focal dilatation of fluid-filled bowel segment noted on contrast enhanced CT scan and acute hematoma on unenhanced CT scan.
Evaluation of GIB with CTA may provide concurrent localization of active hemorrhage and diagnosis of the underlying cause, and can also have important treatment and management implications, as it provides high quality thin section data with postprocessing techniques as MPR, CPR, MIP, SR, VR, and endoluminal imaging which lead to accurate localization of the anatomical site of bleeding, as well as depicting the specific bleeding vessel, leading to rapid targeted embolization without the need for preliminary angiography of all territories.
Other data
| Title | Role of Multidetector Computed Tomography Angiographyin Acute Gastro Intestinal Tract Bleeding | Other Titles | دور التصوير الوعائي بالأشعة المقطعية متعددة المقاطع في حالاتالنزيف الحاد بالجهاز الهضمي | Authors | Doaa Abdelaziz Abdelsalam Anany | Issue Date | 2015 |
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