Digestion & Metabolism 2: Radiology of GI NORMAL Flashcards
why do we perform contrast radiography for GI?
NORMAL rads do not allow enough contrast for GI detail!
POSITIVE CONTRAST MAKES THE GI LUMEN…
MORE OPAQUE
BARIUM SULFATE…
what kind of contrast is this?
commonality?
exception? (2) & why?
this is a POSITIVE contrast
commonality?
USED MOST OF THE TIME FOR GI RADS
exception = SUSPICION OF RUPTURED GI TRACT
1. such as CHRONIC FORIENG BODY
2. or ULCER
why? –> if BARIUM leaks into peritoneal cavity, can cause PERITONITIS
IODINATED CONTRAST MEDIUM…
what kind of contrast is this?
when is it indicated?
prefer WHAT specific type?
POSITIVE CONTRAST medium (makes GI lumen opaque)
indications?
–> if there’s a SUSPICION OF RUPTURED GI TRACT and DO NOT WANT TO USE BARIUM
specific type?
prefer NON-IONIC because THEY DO NOT BECOME DILUTED AS FAST AS THE IONIC ONES when in lumen of GI tract
DOUBLE CONTRAST GASTROGRAPHY…
used to look at WHAT?
HOW does it do this?
how is it performed? (2)
how many/what rads are taken? (4)
used to look at GASTRIC WALL LESIONS (masses, ulcers, polyps) because it provides GOOD DETAIL OF GI SURFACE MUCOSA
air in the LUMEN + BARIUM coating the MUCOSA allows SURFACE OF MUCOSA TO BE VISUALIZED
how is it performed?
1. animal must be ANESTHETIZED so that STOMACH IS PARALYZED
2. inject NEGATIVE contrast (air or CO2) into stomach, and then POSITIVE contrast (barium)
how many/what rads are taken? –> 4 TOTAL
1. VD
2. DV
3. R LATERAL
4. L LATERAL
POSITIVE CONTRAST GASTROGRAPHY…
what is it used for?
how do we perform it?
used to look at the POSITION of the STOMACH when we’re worried it’s SHIFTED OUT OF POSITION
administer ONLY BARIUM
UPPER GI CONTRAST SERIES…
= what is it?
= SERIAL rads taken after administering ORAL BARIUM at SPECIFIC TIME INTERVALS to determine GI MOTILITY
2 things it can do?
1. VISUALIZE THE ENTIRE GI TRACT
2. DIAGNOSE MECHANICAL SUB-OBSTRUCTION or OBSTRUCTION
BARIUM ENEMA or DOUBLE CONTRAST ENEMA…
= what is it?
what is it SPECIFICALLY used to diagnose?
for DOUBLE contrast, what can it also visualize?
why is this technique RARELY used?
= putting either JUST BARIUM or BARIUM + NEGATIVE CONTRAST (air or CO2) into ANUS DIRECTLY to VISUALIZE COLON
used to DIAGNOSE ILEOCOLIC INTUSSUSCEPTION (when one part of the bowel enters another)
double contrast = GI WALL LESIONS
RARELY used bc ENDOSCOPY MORE EASILY DONE AND AVAILABLE
in DOUBLE CONTRAST GASTROGRAPHY, the BARIUM will always fall to the most ____ portion of the ____, aka “….”
LEFT lateral = ??
RIGHT lateral = ??
DEPENDENT, STOMACH, AKA THE PORTION CLOSEST TO THE TABLE
LEFT lateral = FUNDUS
RIGHT lateral = PYLORIC ANTRUM
taken on the RIGHT lateral surface
what method is this?
where is the contrast medium CLOSEST to?
DOUBLE CONTRAST GASTROGRAPHY
closest to the PYLORIC ANTRUM
taken on the LEFT lateral surface
what method is this?
where is the contrast medium CLOSEST to?
** what else can we see?
DOUBLE CONTRAST GASTROGRAPHY
closest to the FUNDUS
** can see the RUGAE/FOLDS
what method of imaging is this?
what are we able to see?
UPPER GI BARIUM SERIES
what method of imaging is this? WHAT IS LIT UP?
this is a BARIUM ENEMA with BARIUM IN LUMEN OF COLON
what method of imaging is this?
describe a little what’s going on
labels? (C, 1, 2-3, 4-5)
DOUBLE CONTRAST ENEMA
AIR IN THE LUMEN, BARIUM COATING THE WALLS to look for LESIONS
labels?
C = CECUM
1 = ILEOCOLIC JUNCTION
2-3 = ASCENDING COLON
4-5 = DESCENDING COLON
explain this image
BARIUM (positive contrast) from within the LUMEN of the GI tract can LEAK OUT TOWARDS GI WALLS due to something pathologic like an ULCER/CRATER, but it can also be NON-PATHOLOGIC…
such as a PEYER’S PATCH, lymphoid structure in MUCOSA of intestine, which is THINNER to allow lymphoid cells to be exposed to lumen of GI. so, this causes a LITTLE DEPRESSION that can also concentrate barium
what kind of defect is this? describe it briefly
INTRA-LUMINAL FILLING DEFECT = area INSIDE of lumen of intestine NOT PICKING UP CONTRAST with CONTRAST MATERIAL AROUND IT
what kind of defect is this? (name & description)
what’s 1 example of what this could be?
INTRA-MURAL or MURAL FILLING DEFECT = the filling defect is CONTINUOUS with the wall of the INTESTINE
example?
1. TUMOR of the intestinal wall
what is this defect?
1 example??
EXTRA-LUMINAL or EXTRA-MURAL FILLING DEFECT = a BIG MASS on outside of intestinal lumen causing LESS CONTRAST TO ACCUMULATE IN GI TRACT
example?
1. BIG SPLENIC MASS
which stomach is a cat and which is a dog’s? describe!! (2 for each species)
in DOGS… (BOTTOM)
1. stomach is PERPENDICULAR TO THE SPINE
2. CROSSES OVER MIDLINE from LEFT to RIGHT in cranial abdomen
in CATS… (TOP)
1. stomach is LEFT-SIDED and J-SHAPED
2. DOES NOT CROSS MIDLINE
3 parts of the stomach?
- FUNDUS = LEFT-SIDED & MOST DORSAL
- BODY = MIDDLE
- PYLORIC ANTRUM = RIGHT-SIDED & MOST VENTRAL
describe what PROJECTION this is & WHY using where the FLUID AND GAS are located!
RIGHT LATERAL PROJECTION
FLUID = IN MOST DEPENDENT PORTION, so it’s in the PYLORIC ANTRUM
GAS = AWAY FROM DEPENDENT, so it’s in the FUNDUS
describe what PROJECTION this is & WHY using where the FLUID AND GAS are located!
LEFT LATERAL PROJECTION
FLUID = IN MOST DEPENDENT PORTION, so it’s in the FUNDUS
GAS = LEAST DEPENDENT, in the PYLORIC ANTRUM
describe what PROJECTION this is & WHY using where the FLUID AND GAS are located!
DV PROJECTION!!!
FLUID = in most DEPENDENT area, so in PYLORIC ANTRUM (most VENTRAL)
GAS = in FUNDUS
describe what PROJECTION this is & WHY using where the FLUID AND GAS are located!
VD PROJECTION!!
FLUID = in most DEPENDENT portion, so in FUNDUS (most DORSAL)
GAS = in PYLORIC ANTRUM
what view should we use if an animal is VOMITING and we’re concerned about a FOREIGN BODY? why?
should take a LEFT LATERAL VIEW because GAS WILL RISE UP TO PYLORIC ANTRUM/PYLORIC REGION of stomach, where FOREIGN BODIES TEND TO OCCUR & EASIER TO SEE
describe this diagram and why radiographs cannot be used to measure the THICKNESS of GI wall
GI WALL has the SAME OPACITY as FLUID, so when a BEAM GOES THROUGH, BOTH THE FLUID & WALL WILL SUMMATE
name type of IMAGING & 1-4 labels!
what SIDE is this organ in?
UPPER GI BARIUM SERIES
1 = STOMACH (in cranial abdomen)
2 = DESCENDING DUODENUM
3 = CAUDAL DUODENAL FLEXURE
4 = ASCENDING DUODENUM
DUODENUM IS ON THE RIGHT SIDE
why is the SIZE/DILATION of the intestine important to measure?
INTESTINE PROXIMAL to the foreign body will become DILATED because NOTHING CAN PASS THROUGH
normal dilation of INTESTINES in DOGS (2) vs. CATS (1)?
DOGS…
1. 1-1.5X the HEIGHT OF THE BODY OF L5
2. 2-3X the WIDTH OF A RIB
CATS…
1. ~12 MM INTESTINE DILATION
radiographically viewing the CECUM in DOGS vs. CATS? (main thing & 2 for each)
DOGS = EASY TO SEE
1. LARGE
2. GAS-FILLED STRUCTURE
CATS = CANNOT BE SEEN ON RADS
1. SMALL
2. DOES NOT CONTAIN GAS
what should FECAL content look like?
what does it help VISUALIZE?
FECAL CONTENT should look RADIOPAQUE with STIPPLED APPEARANCE and can help VISUALIZE THE COLON
(look at C)
what are these structures?
we should be looking for…
how do we know this ISN’T ulceration?
PEYER’S PATCHES along the VENTRAL INTESTINAL WALL (duodenum)
look for OUTPOUCHING of CONTRAST MATERIAL
IS NOT ulceration because HAS REGULAR BORDERS
what pattern is this? what species?
= what does it represent?
pathologic?
STRING OF PEARLS PATTERN often found in CATS
= represents SUCCESSIVE PERISTALTIC CONTRACTIONS of the INTESTINAL WALL
THIS IS A NORMAL FINDING
what pattern is this? look at DUODENUM
how do you know what species this is?
PSEUDO-STRING PATTERN = barium is arriving in EMPTY LUMEN but HAS NOT STARTED TO CAUSE DISTENSION; can see LONGITUDINAL FOLDS and that creates this pattern TRANSIENTLY
STOMACH IS ON THE LEFT SIDE so it’s a CAT
WHY would we perform US rather than RADS on GI?
5 specific indications?
NOT POSSIBLE TO ACCURATELY LOOK AT INTESTINAL OR GASTRIC WALL USING RADS because of SILHOUETTING, so US CAN DO THIS
5 specific indications?
1. Suspected gastric or intestinal neoplasia or TUMOR on WALL
2. Gastric outflow obstruction
3. Intestinal obstruction
4. Intussusception (bowels entering one another when they shouldn’t)
5. Infiltrative or inflammatory bowel disease
WHEN/WHY do we FAST patients for ABDOMINAL US?
why would SEDATION also possibly be indicated?
WHEN?
FASTED AT LEAST 12 HOURS
WHY?
FOOD or AIR INGESTED can cause ARTIFACT or ACOUSTIC SHADOWS that can OBSCURE GI STRUCTURES
SEDATION?
only if animal is HEAVILY PANTING (taking in a lot of air)
for any organ we examine on US, we take images in….
2 PLANES!! LONG AND SHORT AXIS
name the 2 axes
BLUE = LONG AXIS
YELLOW = SHORT AXIS
what US view is this of the STOMACH?
what is the wiggly area?
difference between top and bottom images?
SHORT-AXIS of STOMACH
wiggly area?
= CURVILINEAR PROXIMAL GASTRIC WALL with RUGAL FOLDS
difference?
TOP = If food or gas ingesta present in lumen, then DARK AREA OBSCURES FAR FIELD
BOTTOM = If NO FOOD, then just FLUID which is ANECHOIC CONTENT that allows you to see DISTAL WALL OF STOMACH
what VIEW of the stomach on US is this?
LONGITUDINAL view!
what is this US image showing?
PYLORODUODENAL JUNCTION
how do I know this is the PYLORUS or PYLORIC SPHINCTER
has BRIGHT MUCOSAL LINING around it!
what is the GAS in the stomach doing on US?
GAS IS HYPERECHOIC and OCCLUDING ANYTHING THAT’S BELOW IT
what is INSIDE the intestinal lumen on US?
FLUID
what kind of imaging modality is this?
name the 5 layers from IN to OUT?
this is US of SHORT-AXIS VIEW OF SMALL INTESTINE
5 layers IN to OUT?
1. MUCOSAL SURFACE
2. MUCOSA = INNERMOST, HYPOECHOIC/DARK region
3. SUBMUCOSA = THIN, HYPERECHOIC
4. MUSCULARIS = THIN, HYPERECHOIC
5. SEROSA = THIN, HYPERECHOIC
difference between these 2 VIEWS of the ____ ____?
TOP = SHORT AXIS
BOTTOM = LONG AXIS
SMALL INTESTINE
what is this? what species is is most easily seen in? difficult in?
ILEOCOLIC JUNCTION
most EASILY SEEN IN CATS, but DIFFICULT IN DOGS because of GAS presence
on ____-____ view, the ____ has a PROMINENT ____-____ and looks like a ____
SHORT-AXIS, ILEUM, SUB-MUCOA, FLOWER
how is the COLON recognized on US? (2)
- THINNEST wall of ENTIRE GI TRACT (1-1.5 mm) because it’s made of MUCOSA
- CONTAINS FECAL CONTENT, so looks HYPOECHOIC/SHADOWING because FECAL MATERIAL BLOCKS/ABSORBS US BEAM
