Fall NMT: GI

Are these parts apart of the small or large intestine

• Duodenum

• jejunum

• ileum

small intestine

Are these parts apart of the small or large intestine

• cecum Ascending and descending colon

• rectum

• anal canal

large intestine

small intestine function

digestion and absorption of nutrients

large intestine function

reabsorption of water (formation of fecal material), some vitamin absorption

Localization techniques for upper GI bleeds

endoscopy

Localization techniques for lower gi bleeds

• Superior anatomical visualization

• must be active

• require IV contrast

Angiography CTA

Localization techniques where higher blood flow= better chances to indetify a bleed

Radionuclide test

• specifically tagged RBCs

T or F: ACUTE GI bleeding is potentiall life threatening

true

what are the two radionuclide techniques to find a GI Bleed when imaging

• Tc- 99m Sulfur Colloid

• Tc-99m tagged RBCs

what is the preffered method of radionuclide techniques to find a GI Bleed when imaging

Tc-99m tagged RBCs

These are characteristics of which radionuclide for a Gi Bleed

• Simpler process/ procedure

• less sensitive

• high-target-to -background ratio

• increased spleen, liver, and bone marrow uptake

• must have an active GI bleed at injection time

• false negatives

• possible under abdomen sites can be missed

• higher radiation doses to liver and spleen

99m-Tc sulfur colloid

when immaging for a GI bleed using sulfuf colloid you should block what area and why

small portion of the liver and spleen since their is a large amount of uptake so the area can look intense

when using Tc-99m sulfur colloid for a Gi Bleed what is the critical organ

liver and spleen

what position and area should be imaged for GI bleed procedure

Supine including the liver to the pubis symphysis

what is the dose range for sulfur colloid GI bleeds

7-10 mCi 99m-Tc Sulfur Colloid through an IV bolus

what imaging is used for a SC GI bleed study

1. ANT flow for 2-3 min

2. ANT static every 1-2 min for 20-30 min

3. obliques, Lats, and POST as necessary

results of a SC GI bleed

• active bleeding OR bleeding most likely seen after 5min of imaging

• appears focal area of inc. activity then becomes more intense ad background decreases

• IF YOU HAVE TO RESCAN YOU HAVE TO RE-INJECT

• Higher bleeds can be missed

These are characteristics of which radionuclide for a GI bleed

• Agent of choice for intermittent bleeding

• Stays in the system for over 36hrs allowing delayed images

• Lower radiation dose to liver and spleen

• Better detection of GI bleed in upper abdomen

Tc-99m RBCs

what imaging is used for a Tagged RBC GI bleed study

1. ANT flow for 2-3 min

2. ANT Dynamic 10-60sec/60-90min

3. Obliq, lats,POST, SPECT as necessary

4. Delayed: 10-60sec/ 30-60min

what is the dose range for tagged RBC GI bleeds

15-25mCi Tc-99m Tagged RBC through IV bolus

when using tagged RBC for GI bleeds wha do you have to watch out for

neck images “bad tags”

reuslts of a Tc-99m tagged RBC GI bleed

• bleeding may be seen on flow since tagged

• Pattern of focal tracer activity that becomes more intense and changes position with time and is not related to normal structures

  • SMALL Bowel: central location moves rapidly

  • LARGE Bowel: peripheral, curvilinear pattern

  • Delayed (+): hard to pinpoint site of bleed

reuslts of a Tc-99m tagged RBC GI bleed

• SMALL Bowel:

central location moves rapidly

reuslts of a Tc-99m tagged RBC GI bleed

• large bowel

peripheral, curvilinear pattern

normal abdominal strucures not related to GI bleed for tagged rbc

liver, spleen, abdominal vessels, kidneys, bladder, stomach, genitals

reuslts of a Tc-99m tagged RBC GI bleed

• delayed (+)

hard to pinpoint site of bleeding

where the blood and tc-99m exit in a GI bleed

through the bowel witht he pt having stool in their blood

is this a negative Sulfur Colloid or tagged RBC

Negative Sulfur Colloid

is this a negative Sulfur Colloid or tagged RBC

Negative Tagged RBC

is this a positive or negative GI bleed

postive (centrally located)

is this a positive or negative GI bleed

positive (small intestine)

is this a positive or negative GI bleed

positive (large intestine)

Cells of the stomach mucosa

• parietal cells

secrete hydrochloric acid

Cells of the stomach mucosa

• Chief cells

secrete pepsinogen and intrinsic factor

Cells of the stomach mucosa

• G cells

secrete gastrin

Cells of the stomach mucosa

• columnar mucin-secreting epithelial cells

alkaline secretions

ectopic/ heteropic gastric mucosa

• located anywhere in sbdomen most freq. in the RLQ

• gastric mucosal secretion can cuase peptic ulcerations

what are the 2s used to describe Meckel’s Diverticulum

• present in Approx. 2% of population

  • under the age of 2

• Approx. 2cm in size

• within 2 feet of the ileocecal

Meckel’s Diverticulum is more present in males or females

males

T or F: imaging for Meckels is mainly preformed in adults

false kids

cause of meckel’s

failure of closure of an embryonic duct

What radionuclide is used for meckel’s imaging

Tc-99m pertechnetate

prep for a meckel’s test

• NPO (makes stomach smaller)

• No laxitives or barium for 3 days prior (irritates bowels mucosa)

• NO potassium perchlorate (blocks Tc uptake)

• Pretreatment for a meckel’s test that enhances visualization

Pretreatment for a meckel’s test that enhances visualization

• pentagastrin (ENHANCES)

stimulates gastric uptake of Tc

• Removed from the market bc of side effects

Pretreatment for a meckel’s test that enhances visualization

• Cimetidine (blocks and holds Tc)

decreases release of Tc into bowel

Pretreatment for a meckel’s test that enhances visualization

• Glucagon (increases)

relaxes smooth muscles, decreases peristalsis, increases persistence in gastric mucosa

positioning for meckels imaging with LEHR or LEAP collimator

Supine including the xiphoid to the symphysis pubis

dose range for meckel’s imaging

5-15mCi pertechnetate FOR ADULTS*** given through iv bolus

• Must caluclate a dose for kids

childs dose calculation

(kids wt) x (adult dose)/ 150lbs

Imaging set up for Meckel’s study

1. ANT flow 1-5sec/frame for 1 min

2. ANY dynamic 30-60 sec/for 30 mi.

3. ANT static 5 min intervals for 30 min.

4. Delay: Obliq., Lats., POST. for eliminating areas of increased activity

Postviod image-moves activity in renal structures

results of a meckes (+)

• focal area with increased uptake

• normally in RLQ

• seen within 5-10 min. of injection

• continuous incr. intensity with imaging

reasons for a false neg. in a meckels study

Failing to image the entire abdomen, small gastric mucosa, removal of Tc by bowel secretions

reasons for a false pos. in a meckel’s study

Intussusception, volvulus, tumor or cyst, renal structures

Intussusception

telescoping of the bowel

Intussusception can be seen as a flase pos for meckels how can it be seen as a false neg.

if blood flow becomes restricted

Volvulus

twisting of the bowel

pos or neg for meckel’s

positive

normal diffuse uptake areas areas seen for meckels

stomach, bladder, kidney

major salivary glands

• parotid

serous cells

3 major salivary glands

• sublingual

mucous glands

3 major salivary glands

• submandibular

mix of serous and mucous cells

indications for salivary imaging

• warthin’s tumor

differation from other malignant/ begign salivary tumors

Indications for salivary imaging

• Xerostomia

evaluation of mouth dryness or other oral cavity / mucous membrane conditions

indications for salivary imaging

• inflammation

of the salivary glands

indications for salivary imaging

• Sjogren’s syndrome

a long-term autoimmune disease where the immune system attacks the glands that make tears and saliva

dose range and radionuclide for salivary imaging

5-10mCi Tc-99m through IV

method of localization for salivary imaging

active transport

psotioning for a salivary study

pt supine with a pillow under the shoulders wl the neck extended with camera ANT over calse and neck as close as possible

imaging foe a salivary study

1. Flow in water position (chin up): 1-2 sec image

2. Dynamic: 1-2 min/ frame 20-60 min or Static: 5-15 (ANT, RLAT, LLAT)

3. Lemon juice to stimulate saliva secretion while imaging

limits to salivary imaging

• not very specific

• poor indicator of anatomy

• useful role in evaluating certain diseases

salivary normal results

• glands have homogenous distribution of Tc

• localization is symmetrical in all glands

• rapid, symmetrical, and profound dec. of radiotracer loalization after lemon juice

waters position does what

prevents super inposition of the glands (imaging on top of eachother)

the lemon juice should do what

cause saliva to releas the Tc equally

is this normal or irregular results for a salivary

normal (neg) wash out is seen equal after lemon juice (arrow)

Abnormal results that could be an indicator of what…

• vasular or connective diseases causing little or no uptake in the salivary glands (dry mouth)

• asymmetric arival in glands or delayed compared to thyroid

• delayed images showing bilateral decreased uptake (little to no repsonse to lemon juice)

Sjogren’s Syndrome

cold (no uptake) spots in a salivary study can mean

metastatic tumor, cyst, abscess, enlarged lymph nodes

what could this salivary test indicate

no salivary glands seen

• Sjogern’s syndrome

what could this salivary test indicate

cold spot warthins tumor

what could this salivary test indicate

normal salivary secretion

what does this salivary test indicate

hypofunction (since the glands are not evenly hot)

what does this salivary test indicate

no function m

a benign mass of tangled up blood vessels /cells that can be small large, or multiply

hemangioma

there are no signs or symptoms to liver hemangiomas, so how are they found

on accident when other imaging tests are being done like CT, ultrasounds, or MRIs

why do they avoid biopsy’s for liver hemangiomas

bc tumors are in high vascular areas so a biopsy can cause bleeding, invasive, and are unecessary

which scan would be better for visualizing a hemangioma, Planar or Spect

SPECT 88% while planar is 55%

what are the 2 types of radionuclides that can be used for a SPEct Hamangioma prodcedure

20-30 mCi Tc-99m Tagged RBC and Tagged RBC PYP (pyrophosphate)

while both 20-30 mCi Tc-99m Tagged RBCand Tagged RBC PYP (pyrophosphate) can be used for a liver SPECT hemangioma what is preffered

20-30 mCi Tc-99m Tagged RBC

method of localization for Tc-99m Tagged RBCand Tagged RBC PYP (pyrophosphate)

compartmental (meaning tagged to and circulating with the blood)

Positioning for a liver SPECT hemangioma

supine

imaging for a liver SPECT hemangioma

1. Flow: based on prior imaging

2. blood pool static: ANT marker, ANT, RAO, RLAT, POST

3. Delay/SPECT: 1-2 hrs later

normal areas of uptake for a liver SPECT hemangioma

Heart, great vessels, spleen and kidneys

liver SPECT hemangioma uptake (delay)

heterogenous uptake of liver parenchyma with the hepatic vessels prominent in various slices

positive liver SPECT hemangioma image

initially hypovascular with filling over time

• cold during blood pool with liver activity being greater than hemangioma

• during delay: hemgioma activity greater and the rest of the liver and heart and spleen are equal

T or F: only hemangiomas retain RBC until the 2 hour interval

true

is this a positive or neg liver hamangioma

positive

what does the portahepatis consit of

• hepatic artery

• portal vein

• bile ducts

75% of blood supply for the liver is via the

portal vein

25% of blood supply for the liver is via the

hepatic artery

venous blood draining from the intestines carried to liver; carries nutrients

absorbed from intestines to liver for processing by hepatocytes

portal vein

arterial oxygenated blood; branch of abdominal aorta

hepatic artery