Download - GI Bleeding Scan
GI Bleeding Scan
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GI Bleeding
1. Upper GI bleeding
2. Lower GI bleeding
Diagnostic Procedures
1. Endoscopic examination
2. Selective angiography
3. GI bleeding scan
Acute Lower GI Bleeding
1. Small bowel bleeding
2. Large bowel bleeding
Causes of Small Bowel Bleeding Regional enteritis Intestinal varices Lymphoma Heriditary telangiectasia Meckel’s diverticulum etc.
Causes of Large Bowel Bleeding
Diverticulosis Inflammatory diseases Arteriovenous malformation Angiodysplasia CA colon, Polyps etc.
Acute Lower GI Bleeding
1. Rigid endoscopy (Proctosigmoidoscopy)
2. Selective angiography
3. GI bleeding scan
Algorithm for the Dx & Rx of Acute Lower GI Hemorrhag
eAcute Lower GI Bleeding
Proctosigmoidoscopy
Rectal fissure, Bleeding site not foundHemorrhoids,
Polyps or CA etc. GI bleeding scan
Surgery or
Therapeutic angiography
Algorithm for the Dx & Rx of Acute Lower GI Hemorrh
ageGI bleeding scan
Positive scan Negative scan
Angiography , Medical treatment
Transcatheter Rx Elective colonoscopy
Persistent bleeding Barium studies, CT etc
Surgery
GI Bleeding Scan
1. Tc99m-Sulfur Colloids
2. Tc99m-labeled Red Blood Cells
Tc99m-Sulfur Colloid Scan
Dose 10 mCi IV Circulation half-time 2.5-3.5 min Active bleeding within 15-30 min Minimal bleeding rate 0.05-0.1
ml/min
Mechanism
To demonstrate an acu te GI bleed
• Extravasation of activit y (increased uptake)
- Time Activity Curves
Negative Tc99m- Sulfur Colloid Scan Normal uptake in -
Liver - Spleen & - Bone marrow
Positive Tc99m- Sulfur Colloid Scan Normal uptake in liver,
spleen & bone marrow Extravasated activity at
bleeding site(s)
Tc99m-labeled Red Blood Cell Scan
Dose 20 mCi IV Active or intermittent bleeding Minimal bleeding rate 0.35
ml/min
Negative Tc99m-RBC Scan
High uptake in - Blood pool organs & - Great vessels of
abdomen
Positive Tc99m-RBC Scan
Normal uptake in blood pool organs & great vessels
Extravasated activity at bleeding site(s)
Scintigraphic Criterias for Dx of GI Bleeding1. Area(s) of extravasated
activity (increased uptake) - Appears and
- Conforms to bowel anatomy
Scintigraphic Criterias for Dx of GI Bleeding 2. Area(s) of extravasated
activity - Persistence or - Increased in intensity
with time
Scintigraphic Criterias for Dx of GI Bleeding3. Area(s) of extravasated
activity can change in - Size
- Configuration & - Location with time.
Scintigraphic Criterias for Dx of GI Bleeding
4. Area of extravasated activity does not initially present, but appears in later images. (intermittent bleeding)
Advantages of GI Bleeding Scan
Noninvasive More sensitive Low cost Low radiation exposure Active or intermittent GI bleeding Venous or arterial bleeding
Tc99m-RBC Tc99m-S.Colloid
Dose 20 mCi IV More complicated Noninvasive Low radiation exposure Lower target/nontarget ratio Active or intermittent
bleeding Bleeding rate >0.35 ml/min Venous or arterial bleeding
Dose 10 mCi IV Simple Noninvasive Low radiation exposure Higher target/nontarget ratio Active bleeding
Bleeding rate > 0.1 ml/min Venous or arterial bleeding
- Negative Tc 99m Sulfur Colloid Sca
n
Small Bowel Bleeding
Terminal Ileal Bleeding
10 20min min
Ascending Colon Bleeding
10 20min min
5 3 0min min
Ascending Colon Bleeding
5 30min min
Mid Descending Colon Bleeding
Descending Colon Bleeding
Sigmoid Bleeding
Rectal Bleeding
- 99Negative Tc m RBC Scan
5 15min min
30 1min hour
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Active Jejunal Bleeding
1 2hr hrs
3 4hrs hrs
Small Bowel Bleedin
g
1 2hr hrs
3 4hrs hrs
45 1min hour
2 3hrs hrs
Small Bowel Bleeding
45 1min hour
2 3hrs hrs
Small Bowel Bleeding
Small Bowel Bleeding
15 1min hour
2 230hrs : hrs
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15 1min hour
2 230hrs : hrs
1 115hour : hrs
10 30min min
Mid Transverse Colon Bleedi
ng
1 115hour : hrs
10 30min min
5 15min min
30 45min min
Rectosigmoid Bleeding
5 15min min
30 45min min