GI Imaging & Radiology Flashcards
when are plain films for GI used
indications
where is air gas normally
- first line to inspect for gross abnormalities during evaluation
- less used now
Indications
- ingested radio-opaque (bright) thing: aka metal
- trauma
- suspected bowl obstruction : see if need urgent decompression
- suspected perforation : see free air
air normally
- some always in stomach
- some in small bowl
- almost always in sigmoid or rectum
- stool: will ahve small gas bubbled
differentiate small and large bowel on Xray
Small: centrally located
valvulae markings of the pila circularis
Large: peripheral
- haustral markings: wont extend across entire lumen of the bowl (just like a diviot inward)
Abnormal Gas
obstruction
functional ileus
Abnormal Gas Patterns
use the 3, 6 9 rule: small bowel = no larger that 3cm, large = no bigger than 6, cecum = no bigger that 9
Obstruction:
- mechanical obstruction: see the transition point: where the change occurs from normal to obstructed
- proximal loops: will dilate as the contents attempts to move through : can be hyperactive bowl sounds and “tinkling sound”
- distal loops: will be airless, and decompress as nothings coming into it
- wont be able to move contents through: not even gas!!!
- peristalsis will increase as body trying to move stuff through
Localized Ileus : paralysis of the bowel: lost peristasis
- sentinel loop: area of bowl which stops/paralysis due to irritation in the bowel : reactive paralyis: not actualy paralysis of the bowel
- generalized adynamic ileus: is actual loss of perstalsis usually post-op (small or large bowel) in whole area
- small bowel: see step=ladder appearance with collapse distal
ask if they are passing gas: this will help show if they are having illeus v obstruction
Obstructions
small
larger
Small BO: cant get past the small bowel
- see dilation prior to obstruction, airless decompressed after
- air wont even pass through
- peristalsis will increase
see step-ladder or paraschutes on imaging
Large BO: cant get past large bowel
- no air in the recto-sigmoid
- increased bowl sounds trying to move through
- colonic dilation seen; cecum in its largest diameter
- **always look for fecal impaction
how are diverticula seen on imaging (what kind)
better seen on CT, MRI and US over xray
- ouchpouching of the colon: most common in the sigmoid
Signs of Free Air in the GI tract on xray
- indicates a rupture of teh GI tract and the release of gas and intestinal contents from the GI tract into the peritoneal cavity
- post-op: this free air oculd be normal: result of opening the pt. up or insufflation from laproscoic
- seen best on LL and upright films
Signs
- air underneath the diaphragm
- visualized on both sides of bowel wall
- falciform ligament sign: the ligmanet being surroundd by free air; normally its insivable (vertical line on xray)
- Riglers Sign: seeing air on both sides of the bowel wall: so the bowl wall is “highlighted” : indicated air in the lumen and the peritoneum
Abnormal Calcifications on Xray
Calcifications: think subacute or chronic processes
- renal calculi
- porcelin gallbladder: outline gallbladder white
- staghorn calculi : struvite/calcium + recurrent UTI or pyleonephritis
- pancreatic calcifications: chronic pancreatitis
- uterine leiomyoma
Barium Enema
- Double Contrast
- contrast (normal)
Barium Enema: inject dye into the rectum with air
- good for colorectal cancer check
- good for detecting pockets, fistualas
- not great at getting small polyps
Contraindications
- suspected perforation in the bowel!!!!
- SEVERE Ulcerative colitis!!!!!
- pregnancy!!!!
colon cancer: apple core sign
UC: loss of normal haustra in LI
Esophagram
what findings/dx can be made with
Esophagram: needing visualization via a “swallow study”
INdication s
- visualized esophageal lumen for
- strictures/masses
- hiatal hernia
-zenker’s diverticulum (hypopharyngeal)
esophagel spasm
if continued into stomach…
- can see gastric uclers: because barum sticks to fiberous tissue for longer than lumenal
if continued to small bowel : small bowel follow-through
- gastric cancer
- duodenal ulcer
- chrons’ disease: see strictures and cobblestoning
Barium Swallow Study
- type of esophagram: using florscopy in real time to evaluate
- motility of the esophagus
- oral phyarngeal function during swallow
- mucosal surfaces
- reflux at GE junction
indications
- dysphagia
- odynophagia
- post CVA/nerologica disease
- aspiration suspect
- recurrent pneumonia (swallow)
US
- abdomenal : used for twaht
Abdominal US
- usually done in evaluation of GB disease (bile ducts dilation)
- good for RUQ pathology
- dependent on the user: need to know what theyre looking for!
Down Side
- not useful for bone
- not great through air: if ileus then you have air trapped
- can really evaluate the bowel
Indications
- free fluid (ascites, bleed, trauma)
- GU: urinary, kidney stone, hydronephrosis
- OBGYN
- hepoatbill: gallstones, stone in duct, abcess/mass jaundice
- GI: appendicitis, intusucception
- vasualr: AAA, renal artery stenosis
US
- abdomenal : used for twaht
Abdominal US
- usually done in evaluation of GB disease (bile ducts dilation)
- good for RUQ pathology
- dependent on the user: need to know what theyre looking for!
Down Side
- not useful for bone
- not great through air: if ileus then you have air trapped
- can really evaluate the bowel
Indications
- free fluid (ascites, bleed, trauma)
- GU: urinary, kidney stone, hydronephrosis
- OBGYN
- hepoatbill: gallstones, stone in duct, abcess/mass jaundice
- GI: appendicitis, intusucception
- vasualr: AAA, renal artery stenosis
FAST Exam with US
Focused, abdomen, sonograph in trauma
- look for fuid and blood injury with 4 views
- pelvic bladder
- left flank/spleno-renal junction
- right flank: RUQ/morrisons pouch (first area of fluid setteling when laying
- sub-xiphoid: tamponade, pericardial/pulmonary effusions
CT Scan
Indications
Limitations
Specifics for Trauma CT scan
INdications
- abdominal pain: cane be better than an xray
- colitis, pancreatitis, liver disease and appendicitis
- trauma
- abnormal PE findings
- abcessess or infection evaluation
- good at looking at the edges: so this can help distinguish where a pathology starts/stops
- cancer staging
Limitations
- pt. needs to be stable enough to lay in the CT scanner: it takes a while
- raditaion expsoure
- contrast exposure
Trauma CT
- study of choice in abdominal trauma is a CT
- IV contrast ALWAYS indicated: do the head first without contrast, then add
- PO not given: dont know if bowel is ruputrued
- can give rectal
CT
when to use IV contrast
when to use PO contrast
downsides of contrast
IV Contrast
- shows organs more easily
- good for abcesses
- artery/venous evaluation
- enhances masses for cancer stages
PO contrast
- good for GI tract evaulation
- PO contrast usually given for every abd.pelvic CT unless dye in given via enema
- good for bowel disease, obstruction, fluid or mass
Downsides of Contrast
- renal failure know their GFR: risk for ATN
- allergic reaction: can pretreat with steroids
- glucophage: stop metformin/hold prior to giving contrast: risk of ATN
How are Masses evaluated through a CT
triple phase
- first: no contrast
- then: arterial contrast
- then: venous contrast (as it flows)
Liver Masses
- can be isodense: meaning they woud loook the same as the lvier without contrast: hence why we do contrast
- mets in the liver most commonly
- HCC: the most common primary malignancy (solitary, isodense lesion with vasculature)
How is Cirrhosis seen on CT
How is Liver Trauam seen on CT
Cirrhosis
- inititally: see fatty infiltration on the lvier
- then it becomes lobulated
- then it shrinks
- mottled appearance
- potral hypertension & varices can occur
- then splenomegaly due to back flow of portal hypertension
- ascites
LIver Trauma
- ususally a fall or MVA causes liver trauma
- need contrast CT to diagnose
- see the following….
- lacerations
- subcapsular hematoma
- wedge-shpaed infarct
- pseudoanyuresm
- acute hemorrhage
Biliary System
- what is the imaginge of choice for acute cholysistitits
- what do you see on CT
Spleen CT
Acute cholycystitis: US is the imaging of choice: a CT is less sensitive at detecting the stones
CT findings
- thickenc GB wall, pericholecystic fluid, air in the GB
Spleen CT
- MVA: deceleration
- use IV dye
Pancreas & CT findings with disease proceesses
acute pancreatitis
pancreatic cance
Acute pancreatitis
- can be a clinical dx. but CT can help define why its occuring
CT findings
- enlargement of pancrease
- stranding or fluid collection
- pseudocyst formation
Chronic Pancreatitis
- multiple, clacifications with dilated ducts and pancreatic atrophy
Pancreatic Cancer
- tumors mostly in the head of pancrease: thus jaundice
CT findings
- focal pancreatic mass on CT
- dutal dilation: stumor obstructiong outflow
Small and Large Bowel Findings on CT
normal
hemorrhage
infiltration/inflammation
air
Normal: can see thickening of the bowel: up to 3 mm is normal
hemorrhage: can see submucosal edema “thumbprinting”
infiltration of fat: inflammatory reaction outside teh bowel appear hazy/stringy
air: extralumnial air/contrast: sign of air = perforation (to the OR!)
CT findings
Colitis
Shock Bowel
Appendicitis
- thickened bowel wall
- thumprinting
- infiltration
- mesenteric ischemia: lack of blood flow due to occluded vessels
Shock Bowel: due to hypotension
- diffuse thickening of small bowel wall
- increase enhancement
- fluid filled and dilated loops of bowel
- smaller IVc and Aorta: since hypotensive
Appendicitis
- dilated appendix ( > 6 mm)
- periappendiceal inflammation
- enflammed wall of appendix
- appendicolith
- perforation
Role of a HIDA Scan
what does it show
indications
Hepatoiminodiacetic acid tagged tecnetium-99
- evalutes the PATENCY of teh cystic duct & common bile duct
- shows proper billary function: does it fill or no
- should light up as the IV readitracer is injected (60 mins later)
Indications
- evaluate acute cholycycstitis & biliary obstructions
- can be combined with morphine to induce sphincter of odi spasm (provoke)
- evalute for biliary leak after cholecestecomy
How does a Tagged RBC Scan work
RBC tagged with radioactive tracer: evaluate for hemorrhage in GI tract
- very sensitive for detecing the hemorrhage!(better than arteriography)
GI Bleed
- stable pt + BRBPR
- stable pt + hematemisis
- unstable + BRBPR
- untable, GI suspect
Stable + BRBPR: bleeding scan
stable + hematemisis: endoscopy
unstable + BRBPR: straight to arteriography
unstable + sus GI bleed: colonscopy, upper endo or bleeding scan
Arteriography for GI bleed
- catheter placement into artery; shoot die & see with imaging & treat right there
Reasons for arteriography to be done
- most commonly: the GI bleed will be hemorrhage
- mesenteric ischmia: arteiral occlusion can be suspected: then do arteriogrograhy (acute and chronic)
Arteriogram: can be used to detect hemorrhage elsewhere in GI tract or for AV malformations/anyuresums (becuasegram : picture
Interventional Procedures
ateriographty
G/J tube
biopsy
TIPs
Procedures for GI Bleeding
Arteriography (its own card with detail)
G/J tube placement
- long term feeding if unable to tolerate PO
- NG tube the inflate stomach: then percuta. access to stomach to get to tube
abcess drain placement
- percutaneous, transrectal or transvaginal
- US ot CT guided to drain
biopsy
- biopsy percutaneuous anything
- bile duct can biopsied via ERCP or biliary cateter
- liver, pancreatic masses can be percut. biopsy
- colonic masses can be biopsed via colonscopy
TIPS: for liver to shunt blood from portal vein to hepatin vein
- to help decrease variceal bleeding: when all else fails
- attempt to divert the blood to save the liver; but mortality high still
- shunt from portal vein to hepatic vein
Cholecystostomy
indications
Indications: a drain within the gallbladder
- for those who cannot undergo a cholycysectomy with acute cholyangitis
- temporary: for those in shock, ICU, etc. while the recovery: then get them in for cholycysectomy
US findings
- wall thickening
- dilation
- obstruction
- pericholecystic fluid
- gas
- rim ehncement
post-porcedure issues
- worsening sepsis due to bactermiea
- tube must stay clear!
- stay in-pt. 4-6 weeks to track
- culutre to find out what the infection is
Biiary Catheter (PTC) “T tube”
a catheter place percut. into th eliver and then into the bile duct : fed down through bile duct and into duodenum
Indications
- biliar obstruction: stone/mass/etc.
- bile leak: injury in bile system due to cholecysectomy
- divert th ebile away to allow injury to recover
