Chest/Abdominal Imaging Flashcards
Most kidney stones occur in what 2 locations?
- ureteropelvic junction (UPJ)
- ureterovesicular junction (UVJ)
What is the sensitivity and specificity of CT scan for cholecystitis?
- sensitivity = 94%
- specificity = 59%
Chest CT is the imaging modality of choice in these 4 occasions.
- assess advanced parenchymal lung disease
- evaluate nodules/clarify abnormalities
- assess for traumatic injuries
- assess for PE
What is a Magnetic Resonance Cholangiopancreatography (MRCP) used for?
- Non-invasive imaging of the biliary and pancreatic ducts
What CT protocol is used for cholecystitis?
O+/I+
What are the 2 most common causes of SBO?
- adhesions s/p surgery
2. hernias
What is the sensitivity and specificity of CT scan for cholelithiasis?
- sensitivity = 55-80%
- specificity = 100%
What is the 1 caveat to a V/Q scan?
-requires normal chest XR
What are the 2 oral contrast agents available? Which one is most commonly used?
- Diatrizoate (Gastrografin) (most common)
- Barium sulfate
What does KUB stand for?
- Kidney
- Urether
- Bladder
Why is a CT necessary in a bowel obstruction?
you can see the transition point
What imaging study offers quick, non-invasive screening test for radiopaque foreign bodies?
KUB
Cholelithiasis can be composed of what?
- cholesterol
- bile
- calcium
or mix
What is the difference between hydronephrosis and hydroureter?
- hydronephrosis = dilation of the renal pelvis
- hydroureter = dilatation of the ureter
both signs of obstruction
This is a hyperlucency secondary to a collapsed appearance of vessel distal to the occlusion that may be seen on CXR in a patient with a PE.
Westermark sign
A coffee bean sign seen on KUB is consistent with what?
volvulus
The small bowel is made up of circular folds termed _______.
The large bowel is made of small pouches of colon termed _______.
- small bowel = plicae circulares
- large bowel = haustra
Which of the following is both diagnostic and therapeutic? (MRCP or ERCP)
ERCP
The majority of aneurysms are located where?
infra-renal
How dilated does the lumen have to be to diagnose appendicitis?
> 6mm
Barium sulfate is contraindicated if you are concerned for what?
intestinal perforation or bowel obstruction
What 4 findings on a KUB are consistent with a SBO?
- dilated small bowel >2.5 cm
- Air fluid levels
- Stacked coins
- String of beads
T/F: CT is not usually required to make the diagnosis of pancreatitis.
True
D-Dimer is an excellent test to rule in or rule out PE?
rule OUT
This term is defined as gas or air trapped within the peritoneal cavity but outside the lumen of the bowel.
Pneumoperitoneum
What is the upper limit of large bowel dilatation?
What is the upper limit of cecum dilatation?
- large bowel = 6 cm
- cecum = 9 cm
What CT findings are consistent with cholecystitis? (4)
- cholelithiasis
- thickened gallbladder wall >3mm
- pericholecystic fluid
- gallbladder distension
What is the difference between diverticulitis and diverticulosis?
- diverticulitis = inflammation of the diverticula
- diverticulosis = outpouching of colonic mucosa
This is a colonic distention as a complication of IBS or infectious colitis w/o mechanical obstruction.
Toxic megacolon
What CT protocol is used for nephrolithiasis?
O-/I-
contrast may mask stones
What GFR value can you proceed with IV contrast?
At what GFR value do you need to use caution and make sure the patient is well hydrated before IV contrast?
At what GRF value is IV contrast avoided unless their is an emergency?
- GFR >60 = can proceed with IV contrast
- GFR 30-60 = caution
- GFR: <30 = only if an emergency
When obtaining a KUB what 2 views do you need?
supine + upright
Most kidney stones appear _______ on CT.
hyperdense
What CT protocol is used for a AAA?
CTA O-I+
What abdominal aorta size indicates an aneurysm?
> 3cm
This is defined as sudden deterioration in renal function after contrast w/o any other explanation usually 24-48 hours after exposure.
contrast induced nephropathy (CIN)
What CT protocol is used for colitis?
O+I+
What is the difference between cholelithiasis and cholecystitis?
- cholelithiasis = gallstones
- cholecystitis = inflammation
T/F: PE can be diagnosed with an XR.
False
What is a Endoscopic retrograde cholangiopancreatography (ERCP) used for?
- Invasive imaging of the biliary and pancreatic ducts
What findings on a V/Q scan is positive for a PE?
-normal ventilation + abnormal perfusion
What are 3 imitators of appendicitis?
- right sided diverticulitis
- mesenteric adenitis
- epiploic appendagitis
What CT protocol is used for appendicitis?
O+/I+ or R+/I+
What do the following terms mean?
a. fat stranding
b. hyperemia
c. contrast blush
a. fat stranding = density within fat
b. hyperemia = increased blood flow
c. contrast blush = hyperdensity representing active bleeding
This is a dome shaped opacification d/t PE seen on CXR.
Hampton’s hump
delete
- pregnant women
- children
if u/s not available
What is the general cut off for a surgical repair of AAA?
> 5.5 cm
How will a PE appear on a chest CT?
will appear as a filling defect
Abdominal radiography detects what % of stones on CT scan?
30-60%
What are the 2 most common causes of pancreatitis?
What is the most fascinating cause of pancreatitis?
- most common = alcohol + gallstones
- most fascinating = scorpion stings
What are the pulmonary embolism rule-out criteria (PERC) for low-risk patients with consideration of PE? (8)
- Age <50
- Pulse <100
- O2 = 95%
- No hemoptysis
- No estrogen use
- No surgery/trauma requiring hospitalization within 4 weeks
- No prior venous thromboembolism (VTE)
- No unilateral leg swelling
If any one is false = proceed with d-dimer
Foreign bodies in the abdomen most often occur in what population?
men in 30-40s
What CT protocol is used for diverticulitis?
O+I+
What imaging study is required to assess for PE?
Chest pulmonary angiography
What is the sensitivity/specificity of PERC?
- High sensitivity (96-100)
- Low specificity (15-27)
