Gastrointestinal Bleeding Scintigraphy

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Gastrointestinal Bleeding ScintigraphyTopic in Nuclear Medicineby Mr.Kiattisak Promsensa

GI Bleeding

•Upper, above the ligament of Treitz,

•Lower, distal to the ligament of Treitz

Clinical PresentationUGIH LGIH

Melena √Hematemesis/ Coffee ground

Maroon stool √ √Red stool √ √Stool occult blood √ √

Causes of Upper GI bleeding

LINDA L. MANNING-DIMMITT, D.O. Diagnosis of Gastrointestinal Bleeding in Adults. Am Fam Physician 2005 Apr. 1;71(7):1339-1346.

Causes of lower GI bleeding

LINDA L. MANNING-DIMMITT, D.O. Diagnosis of Gastrointestinal Bleeding in Adults. Am Fam Physician 2005 Apr. 1;71(7):1339-1346.

Initial management

•Patient assessment, V/S, signs of shock•Resuscitation•Retain NG tube•Proctoscope•Identifying cause

Investigations

•Endoscopycan determine bleeding site about 48-90%, biopsy or therapeutic procedure could also perform.

Investigations

•Angiographycan detect bleeding site when the source is arterial bleeding with rate > 0.5 cc/min, can also stop bleeding by embolizing material

Investigations

•Scintigraphy with labeled RBCsgood sensitivity (0.1-0.35 cc/min), but not accurate for identification of bleeding site and no therapeutic option included.

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พญ. พ�นพ�สมั�ย สวะโจภาวะเลื�อดออกในทางเด�นอาหาร

Gastrointestinal Bleeding Scintigraphy• complementary to

endoscopy and angiography

• continuous monitoring over hours

• can detect bleeding rates as low as 0.1 to 0.35 cc/min.

Common Indications

•To locate the bleeding site•To determine who requires aggressive

treatment VS medically treatment

Precautions

•Hypotension/Shock•Misadministration to the wrong patient

Information Pertinent to Performing the Procedure•History of past bleeding episodes

▫Number of transfusions in the past▫Results of prior studies to localize the

bleeding site▫Prior therapeutic interventions▫History of factors that affect RBC

radiolabeling efficiency (e.g. thalassemia, chemotherapy)

•Current blood pressure and pulse•Clinical signs of active bleeding

▫Presence of orthostatic hypotension▫Change in resting pulse rate from supine to

erect position▫Frequency and volume of bleeding▫Current hemoglobin and hematocrit▫Recent hemoglobins and hematocrits▫Number of recent transfusions

•Suspected location of bleeding▫Results of nasogastric aspirate and/or

upper gastrointestinal endoscopy▫Results of sigmoidoscopy or colonoscopy

Radiopharmaceuticals

•The in-vitro method for labeling red blood cells is preferred

•The in vivo method is not recommended

Image Acquisition

•Continuous acquisition : frame rate 1 frame / 10–60 sec

Equipment

•Camera: Large field-of-view•Collimator: A low energy, all-purpose,

parallel hole collimator is preferred.•Photopeak: Typically 20% window at 140

keV•Computer: 128 x 128 matrix, single or 2-

byte mode

Patient position

•Supine

Imaging field

•Abdomen and pelvis

Acquisition Protocol

•Abdominal Flow Study▫Anterior abdominal flow images (1–5

secs/frame x 1 min) are recommended.

•Dynamic Abdominal Imaging▫Dynamic anterior abdominal images :

- frame rate of 10–60 sec / frame - 60 - 90 min. - multiple sets of 10–15 min.

▫If computer acquisition is not possible: - Sequential static images 1 million counts / image- at least every 5 min for 60–90 min.

•Delayed Imaging (optional)▫For Tc-99m RBCs, if no bleeding site is

identified on the initial 60–90 min▫2–6 hr and/or at 18–24 hr after the

injection of the radiopharmaceutical

•Additional Views▫Lateral views : rectal bleeding▫Anterior oblique and posterior views : if

activity is located anteriorly VS posteriorly

Interventions

•Glucagon : decreases intestinal peristalsis and increases vasodilatation

•Heparin : suggested as an adjunct to GI bleeding studies in patients with recurrent bleeding from a site that has not been localized using standard diagnostic tests

Processing (optional)

•subtraction/contrast enhancement•blood loss estimation

Interpretation Criteria• Accurate interpretation of GI bleeding

scintigraphy requires knowledge of the normal and abnormal variations in the abdominal vascular space

• Labeled red blood cells rapidly reach equilibrium within the vascular space of the liver, spleen and great vessels.

• It is normal for some radioactivity to be excreted in the urine and the urinary tract to be seen even when in vitro labeling is used

Extravasated radiolabeled RBCs•Extravasated radiolabeled RBCs within

the lumen of the bowel are identified as an area of activity that increases in intensity with time

•And/or focus of activity that moves in a pattern corresponding to the lumen of the large or small bowel.

•Small bowel bleeding usually can be distinguished from large bowel bleeding by its rapid serpiginous movement.

The patient, a 37-year-old male with a history of peptic ulcer disease, presented to the emergency department after syncope. At the time of presentation, the patient’s hemoglobin was 6.8 g/dl, and stool guaiac was positive.

Brian Wosnitzer, MD and Ramesh Gadiraju, MDRadiology Case Reports, Vol 5, No 4 (2010)

•Low bleeding rate are visualization of blood - after one hour and- activity less intense than the liver.

•Higher bleeding rates are associated with - early appearance of blood in the bowel and - intense activity equal to or greater than the liver.

An 84-year-old man presented to the emergency room with rectal bleeding. On examination, bright red blood was found in the rectum.

BrighamRADLeyla Azmoun, MD Piran Aliabadi, MD B Leonard Holman, MD

http://brighamrad.harvard.edu/Cases/bwh/hcache/126/full.html

Sequential one-minute picture frames of Tc-99m–tagged red blood cell scan hemodynamically-stable patient presenting with painless bloody diarrhea.

LINDA L. MANNING-DIMMITT, D.O.Diagnosis of Gastrointestinal Bleeding in Adults. Am Fam Physician 2005 Apr. 1;71(7):1339-1346.

Reporting(1)

•Patient demographics•Indication for the study•Procedure•Radiopharmaceutical

▫Dose▫Radiolabeling method for RBCs (e.g.,in-

vivo)▫Method of administration (i.v.)

Reporting(2)

•Acquisition▫Duration of acquisition (e.g., 1 hr)▫Frame rate (e.g., 10 sec/frame)▫Projections acquired (e.g., anterior,

laterals)•Display (e.g., static vs. cine)•Findings

▫Onset▫Location▫Characteristics

Reporting(3)

•Characteristic▫Size and Shape (e.g., focal, diffuse)▫Pattern of movement (e.g. moves vs.

stationary, serpentine small bowel pattern vs. colonic, antegrade or retrograde)

▫Severity (e.g., waxing or waning intensity, qualitative intensity compared to the liver, qualitative volume—large/small)

Reporting(4)

•Study limitations, confounding factors•Interpretation (e.g., positive, negative,

indeterminate) and state location of bleeding site

Extravasation of tracer in ascending colon with accumulation over time in the proximal colon.

Government of Western Australia Department of HealthDiagnostic Imaging Pathways - Gastrointestinal Bleeding

http://www.imagingpathways.health.wa.gov.au/includes/dipmenu/gi_bld/image.html

Sources of error(1)

•Delay in implementing the procedure since bleeding may have stopped.

•Failure to use a computer to display dynamic images as a movie.

•It is important to continue to acquire images after abnormal activity is detected.

•The entire abdomen must be examined before concluding that no bleeding was detected.

Sources of error(2)

•Inexperienced readers may mistake mesenteric varices or penile blood pool for areas of bleeding.

•A full urinary bladder may obscure sigmoid or rectal bleeding.

•Radioactive urine in the renal pelvis of a transplanted kidney, in either the right or left lower quadrant of the abdomen, may look like colonic activity.

Sources of error(3)

•Gastric mucosal and renal activity is seen when free Tc-99m pertechnetate is present.

References

•Patrick V. Ford, MD Society of Nuclear Medicine Procedure Guideline for Gastrointestinal Bleeding and Meckel’s Diverticulum Scintigraphy. February 7, 1999

•Sirikan Yamada, MD Gastrointestinal Hemorrhage

•Poonpitsamai Suwajo Gastrointestinal Hemorrhage

Thank you !