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

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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

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1 115hour : hrs

10 30min min

5 15min min

30 45min min

Rectosigmoid Bleeding

5 15min min

30 45min min