LEARN NUCLEAR MEDICINE
Gastrointestinal · Case 09
Read the history, inspect the study, then reveal the teaching.
IMAGE PLACEHOLDER · Diagnostic study
Original study · Companion image placeholders
Clinical history
66-year-old male presents with BRBPR, a tagged RBC study is performed to evaluate for a GI bleed.
Read the images before opening the teaching panel below.
GI bleed beginning in the small bowel.
Imaging Findings
On the initial images there is focal uptake in the left abdomen which continues to increase in intensity and size over the course of the examination. The shape of the activity is consistent with small bowel loops.
Essential Facts
What are the types of GI bleeds?
Upper GI Bleeds which are proximal to ligament of Treitz (esophagus, stomach, duodenum) can present with hematemesis as well as melena, and if brisk bright red blood per rectum (BRBPR) 15% of the time.
Lower GI Bleeds which are distal to ligament of Treitz can present with melena or hematochezia
Scan Information
Importance:
Better sensitivity than angiography
Bleed localization
Indications:
BRBPR
Active GI bleed
In reality
Drop in Hematocrit
Previously bled, negative colonoscopy
Protocol:
Ideally IR should be on board and ready to embolize if positive
Tc Sulfur Colloid
10 mCi; dynamic images for 20-30 minutes
Rapidly cleared by the liver
Tagged RBC
25 mCi
Us In Vitro Ultra tag kit
Want high labeling efficiency so that you don’t get gastric uptake which could progress into bowel
> 97% labeling efficiency
Dynamic images for 60 minutes
Rates as low as 0.05-0.1 ml/min
Pearls & Pitfalls
Study options
99mTc red blood cells
99mTc sulfur colloid.
Consider RBC for intermittent bleeding
References
Ziessman HA, Rehm PK. Nuclear Medicine. St. Louis, MO: Elsevier Mosby; 2011