Exam IV: Abdominal and Pelvic Imaging

Most basic x-ray evaluation of abdomen
No contrast given

You should look for: liver, spleen, kidneys, psoas shadows, intestinal gas pattern

Normal small bowel should be 2.5cm or less
2.5cm to 3cm is borderline
Larger than 3cm is dilated

Stomach with rugae
Circular folds of small bowel mucosa
Haustral folds in colon

Narrow, circular folds represent small bowel
Wider, rounded haustrations show colonic involvement

Multiple loops of dilated small bowel

Circular folds are clearly visible

Note haustrations and tenia when colon fills with air

Colon can become massively dilated

Incidental finding
Only about 15% of gallstones are visible on x-ray
Ultrasound is the diagnostic test of choice when biliary pathology is suspected, not KUB
Not all gallstones require surgery

Gallbladder seen in right upper quadrant (RUQ) outlined by calcifications
Rare, premalignant condition in which the wall of the gallbladder becomes calcified
Risk factor for gallbladder cancer
Requires gallbladder removal because if gets cancer there is no cure and spreads so quickly
Absolute indication for cholecystectomy

Will find swallowed coins, missing jewelry, bullets – any dense object
A KUB is also what we order when the surgeon can’t quite figure out where that last instrument has gone

Includes three separate X-ray films:

1. AP supine abdomen (KUB)

2. AP upright abdomen

3. PA Chest X-ray

Decubitus position is used when patient cannot stand up
Left side down puts the large, smooth edge of the liver at the top of the image – if there is free air it will be seen there

Looks for:
Bowel dilatation (dilation)
Air-fluid levels in the abdomen
Free air beneath the diaphragm

Same patient
When supine, fluid forms a uniform layer, not visible
Standing the patient up shows air fluid levels
It is normal for the intestine to contain air and fluid but not in the same place

Upper GI series (UGI) or small bowel follow through use barium to coat mucosal surfaces and outline the lumen
Iodinated contrast is used instead of barium if perforation is suspected
Double-contrast UGI series (Enteroclysis) uses barium and air to coat the mucosa and distend the lumen

Oral Barium or iodinated contrast
Dynamic flouroscopic examination
NPO overnight
No laxatives or other preparation needed
Includes stomach and duodenum to ligament of Treitz
Barium is visible in the proximal jejunum but it is not included in this study

Ligament of Treitz: filmy layer of tissue on the duodenum; distinguishes from an upper GI and lower GI bleed

Use Upper GI Barium Study to Dx
Herniation of part of the stomach through the diaphragmatic hiatus
Common - found in up to 20% of population

Two types:
1. Sliding type (most common 95%)
2. Para-esophageal
Both can cause reflux, have similar symptoms but different potential complications

Large portion of fundus “pulled up” into mediastinum, gastroesophageal (GE) junction has moved
Herniated portion of the stomach has entrance and exit
Only repaired if severely symptomatic

Fundus of stomach has “flipped up” into mediastinum, GE junction has not moved
Fundus forms a pouch, only one opening
Susceptible to strangulation
Routinely repaired
Twisted stomach above the diaphragm can build up harmful bacteria, and if explodes is right next the heart so is very dangerous

Includes jejunum and ileum
May take up to 5 hours to get through the bowel
Difficult to read individual images without watching the study or reading the report
Roll the patient side to side so barium moves and get lots of information

A tube is placed through the stomach, into the duodenum
Barium coats mucosa, add air to distend/inflate the bowel
Gives excellent detail
Not very comfortable for patient
Constriction of ileum, “apple core” lesion that goes in circular pattern; can be cancer and double contrast will allow you to dx this

Large white mass is overlapping normal bowel
Only tells us that a mass is present on the bowel wall
May or may not be malignant
If no air injected with double contrast, would have missed this
Might not be seen on single contrast study or CT

Single or double-contrast barium enemas require NPO overnight and colonic cleansing (5 liters of GoLytely®)
Barium enema looks for changes in diameter, intraluminal masses, colon polyps, diverticuli, colon cancer
Dynamic flouroscopic examination
Similar information obtained with colonoscopy

Barium is forced into rectum, all the way around to the cecum
Very dense, shows outline clearly
Patient can be rotated and tilted for different views
Does not show details of mucosa well

Large “apple core” lesion- highly suggestive of malignancy
The cecum receives mostly liquid through it, so the apple core wouldn’t give patient symptoms since it is just fluid going through; barium provided this finding or otherwise cancer would have developed
No proximal dilatation – may not have been symptomatic

Single pedunculated (“with stalk”) polyp in the sigmoid colon

Seen as a filling defect within the barium column (minimal detail)

Enteroclysis for small intestine

Barium followed by air, both per rectum

Excellent mucosal detail

Very uncomfortable for patient

Multiple small polyps on double contrast barium enema (BE)
Double contrast gives much more detail than simple barium enema
Polyps need to be removed or become cancerous

Diverticulum – an “out-pouching” or herniation of mucosa through the bowel wall
Very common – 50% of people >50yr have diverticulosis
95% of diverticula are in the descending and sigmoid colon
Rectum has neither haustrations nor diverticuli

Diverticulitis- inflammation/infection that can make you sick
Diverticulosis is a benign condition

May be extremely long - colon length is variable
Not pathological, just unusual
Would be difficult to pass a colonoscope
Patient needed a barium enema because the colonoscope couldn’t get through all the loops and curves

Axial, cross-sectional imaging
Images are viewed “looking from the feet up”
GI tract lumen identified via oral contrast
I.V. contrast provides tissue enhancement, and is excreted by the kidneys
Abdominal CT scan is from dome of liver to perineum, with contiguous “slices” 0.5-1cm thick
Shorter patient- get more info and smaller slices
Taller patient: get less information because larger slices

No matter which imaging method is involved or what part of the body you are looking at, if the image is axial it should be displayed the same way:
The patient’s right side to your left and vice–versa
Anterior is up, posterior is down

Highest slice

Patient’s right on your left and vice-versa

Right hemidiaphragm and liver are most superior part of abdomen

Aorta “lights up” - IV contrast has been given

Small portion of lungs visible

Remember relative densities:

Bone and metal are white

Fat below skin is dark grey

Muscle and organs are lighter gray (heart and liver)

Air is black (lungs, esophagus)

Stomach and spleen are larger
Large vein within liver is portal vein
Still some lung tissue visible posteriorly

Gallbladder is dark – no contrast going there
Stomach has air and contrast material in lumen – air fluid level
IVC is buried within liver

Muscles are more prominent in lumbar region

The first time you see a branch of the aorta you know it is the celiac trunk
Left kidney shows up first

Second large branch of aorta is superior mesenteric artery coursing downward
Large diameter vessel crossing over to vena cava is left renal vein

Aorta splits into iliac arteries – What spinal level? (L4) umbilical cord level

Sheet of tissue with arteries, veins, nerves, lymphatics that covers the GI tract; support system leading to the GI tract and holds it in

Diverticulosis is a simple asymptomatic outpouching of the colon easily seen on barium enema
Diverticulitis is “inflammation of” the diverticula

Signs include:
Multiple pockets of air indicating abscess formation
Bowel wall thickening

Inflammatory changes of diverticulitis are best seen on CT (test of choice)

Denser than normal bile
Not solid stones
Abnormal but may or may not be symptomatic

Greater than 3mm is abnormal
Fluid around gallbladder and thickening of wall
Both are signs of inflammation and probable cholecystitis

Dilation of intrahepatic ducts indicates distal obstruction but does not tell where
If bile cannot be excreted patient becomes jaundiced, eventually leads to liver failure

Ultrasound can measure the diameter of the duct
Greater than 10 mm indicates dilation

Multiple possible causes:
gallstone
benign stricture
malignancy

Hepatobiliary iminodiacetic acid (HIDA) scan
HIDA with radioactive tracer is injected IV, excreted by liver into bile, enters the GB and flows into the bowel

With cholecystitis, the cystic duct is blocked, and there is no visualization of the GB, even on delayed images

Endoscope down throat into 2nd portion of duodenum
Dye injected into ampula of Vater
Endoscope and put into bile duct and inject contrast
Pumping the contrast backwards = retrograde
ERCP gives more detail than US or HIDA scan

Post cholecystectomy

Checks for stones in common bile duct

Negative image

Dye is injected through cystic duct

Darker area is contrast material

Take cystic duct and pump in contrast= white spots in the dark bile duct = gallstones blocking it- can be fatal or cause liver failure so need to remove them

Must be able to pass a guide wire in order to place a stent

Arterial wall is outside stent but does not show on x-ray

Materials containing Iodine and given IV are mildly toxic to the kidneys
In patient with healthy, normal kidneys – no problem
With a patient with renal “insufficiency” – no IV contrast
If the patient is in full blown renal failure – No problem, contrast is removed at next dialysis

IV iodinated contrast material can cause allergic reactions
Rare (0.22 to 0.04 percent of patients)
NOT associated with shellfish allergy

Each image is a “KUB”
First film is taken before contrast is given and then at 5, 10, and 15 minutes

On the five minute film:
Contrast is in the Kidney and collecting system
Kidneys should be roughly equal in size
Calyces should be sharp in outline and symmetrical with equal filling
Ureters are just beginning to show

10 minutes:
Ureters are completely filled
Any calculi (stones) or strictures would be seen here

15 minutes:
Bladder is filling giving a clear outline
Any abnormalities in shape or filling voids within would be visible
Throughout the procedure attention is paid to the rate of filling and any abnormalities would be noted in the report
Post void film would show whether bladder is emptying properly

Performed during cystoscopy by the Urologist
Patient is sedated
Catheters are visible going into ureters and bladder is not filling
Gives excellent detail of collecting system, clearly defines stones or obstruction
Uses the same iodinated contrast as IVP but less toxicity since the kidney does not have filter the material out of the bloodstream

Inject dye into ureters into kidneys (but not filtered by kidneys)
No functional info, just structure of kidneys

Screening modality

Non invasive structural assessment

Can measure size of kidney and characterize renal masses

Evaluate for obstruction

Does not give fine detail

US are test of choice for cysts

Caused by obstruction of urine flow
Presents with severe pain but no change in urine output
Is reversible if treated early
Ultrasound is test of choice

Sagittal view
Provides information about labeled structures but with limited detail
Very dependent upon body habitus- thin patient get excellent images, but more adipose tissue the worse the images

Sagittal image (divides right from left)
Transvaginal imaging places the ultrasound transducer closer to the uterus with less intervening tissue
Provides excellent detail
See endometrium
Doesn’t matter how much adipose tissue aka less dependent upon body habitus

Inject saline into uterus past the cervix= equivalent of contrast
If endometrial polyp – see this

Transvaginal ultrasound is test of choice
Multiple types from benign functional cysts to cystic malignancies
Any time the differential diagnosis includes cysts, anywhere in the body, you think ultrasound
Cysts inside of the ovaries = normal once a month

X-ray contrast is injected into uterus and fallopian tubes through a catheter

Done for infertility or multiple miscarriages

Shows shape of endometrial cavity and checks patency of tubes

Retropyleogram contrast (iodine)

Most common prenatal imaging study
Can check development, determine gestational age, look for abnormalities
Indications and findings too numerous to list here
Transvaginal approach- see clearer imagine

Next step in evaluation of abnormalities found on digital rectal exam or elevated Prostate Specific Antigen (PSA)
Helps to differentiate prostate cancer form benign hypertrophy
Can be used to guide biopsies or placement of radioactive seeds