abdominal and renal imaging lab Flashcards
why order a KUB xray?
– Can be used to evaluate for bowel distention, urinary tract stone/stent, foreign body, and tube placement – cannot be used to rule out free intra- peritoneal gas or detect air-fluid levels
what is a Acute Abdominal Series (AAS)
• Consists of 3 views: – Upright PA Chest, Upright Abdominal X-ray and Flat plate (supine) Abdomen
why order a AAS?
– Shows lung pathology, bowel distention, air fluid levels and free air • helpful if you suspect bowel obstruction, ileus, perforated viscus, or a radiopaque foreign body is suspected, but cannot be relied upon to exclude these disorders – Fast to do, relatively low cost and low radiation exposure – Low yield, the majority of AAS are negative or nonspecific • A negative AAS does not exclude pathology
how do you interpret an AAS?
• Chest (erect, PA or AP) – Look for free air, pneumonia at the bases, pleural effusions • ABD Flat Plate (prone) – Look for gas in rectum, sigmoid, ascending and descending colon, calcifications • Upright Abd (erect) – Look for free air, bowel distention, air-fluid levels, gas pattern, soft tissue masses
what is an ultrasound the test of choice for and also used for?
– Test of choice for: • Biliary pathology - Cholelithiasis, cholecystitis • Trauma Screen - Screen for intraperitoneal fluid/blood (FAST Scan) • Pregnant pelvic pain – ectopic pregnancy, ovarian cyst • Testiclular pain – Also used for • Assessment of hydronephrosis, soft tissue, procedural guidance
what are the strengths of an ultrasound?
• Fast to do, relatively low cost and no radiation exposure
what are the weaknesses of an ultrasound?
• Limited by: operator skill, adipose tissue (fat), air
what imaging is used for suspected biliary colic?
• US is first line • ERCP and MRCP - if suspect Choledocholithiasis • Ct Abd/pelvis with IV and oral contrast can be helpful • HIDA scan of Liver and GB – Functional test of GB – Done if US is negative and still suspect biliary colic
what are indirect signs of acute cholecystitis whenever gallstones are identified on a sonogram:
• Gallstone impacted in the GB Neck (stone in the neck that does not move when the patient’s position is changed). • GB distension (transverse diameter > 4 cm) • “Sonographic Murphy’s sign” - pain when the transducer presses directly over the GB. This is THE most specific sign of acute cholecystitis if associated with gallstones, even without GB wall thickening ( > 3 mm) or pericholecystic fluid • Sludge • GB wall thickening > 3mm (suggesting edema of the wall) • Pericholecystic fluid (most commonly due to GB wall edema or rarely indicating GB perforation)
if you suspect Choledocholithiasis what other tests do you need?
MRCP +/or ERCP – MRCP – diagnostic – ERCP – diagnostic and therapeutic
when should you suspect Choledocholithiasis
– Patients present with Biliary colic and.. • LFT’s elevated in a “cholestatic” pattern (total bili and alkaline phosphatase are elevated to a greater extent than AST and ALT) • Dilated common duct on ultrasound
what does a renal US look for?
Quick and easy • Specifically to look for hydronephrosis
when is US is the imaging modality of choice?
for abdominal and pelvic pain in the pregnant patient/male patients with testicular pain or mass
when is a US used in women/ pregnant women?
• No ionizing radiation = safe for baby • Used to evaluate fetal well being, and threatened miscarriage • rule out ectopic pregnancy, and ovarian torsion • Also good for diagnosing ovarian cysts
what is the purpose of a FAST scan?
– a standard set of ultrasound examinations for the evaluation of injured patients – Purpose: Detect free intraperitoneal fluid, pericardial fluid, pleural fluid, Hemothorax and pneumothorax in trauma patients – Limited sensitivity precludes the use of ultrasound as a definitive test to rule out intraabdominal injury • Used as a quick screening test for trauma patients
Fast Scan – Morrison’s Pouch
• Right flank • Hepatorenal view
FAST scan Left flank
Perisplenic View
FAST scan subxiphoid view
FAST scan pericardial tamponade
FAST scan Pelvic (retrovesicular views)
Ct Scan of the Abdomen and
Pelvis
• Multiple cross sectional images
• Multiple planes
– Sagittal
– Axial
– Coronal
• Allows for reconstructed images
• Usually gives the most information
• Significant radiation exposure
CT planes
Ct Scan of the Abd and Pelvis
• Without contrast (stone protocol)
– test of choice for ureterolithiasis
Ct Scan of the Abd and Pelvis with IV contrast only
– Radiographic test of choice if suspected abdominal trauma
CT scan of abd and pelvic With IV and oral contrast
– Test of choice for suspected
• Bowel pathology
• Solid organ (parenchymal) pathology
• Vascular pathology
• Best test for undifferentiated abd pain - Gives you the most information
what most you confirm before giving IV dye?
good kidney function
• Check BUN, Creatinine, and GFR
when is CT Scan Abdomen/Pelvis with IV and Oral Contrast the test of choice?
• Imaging modality of choice for bowel inflammation/ infection, solid
organ injury/infection, vascular problems and cancer
• Both abdomen and pelvis are scanned (because the bowel is variable in location
with portions in the Abd and pelvis
what does the IV contrast do in CT Scan Abdomen/Pelvis with IV and Oral Contrast
– enhances the bowel wall
– optimizes detection of bowel inflammation and extra-luminal complications
such as perforation, abscesses and fistulae
– Shows vasculature
what does the oral contrast do in CT Scan Abdomen/Pelvis with IV and Oral Contrast
provides better imaging of the bowel
– distends the bowel and highlights the bowel wall.
CT Abd/Pelvis without Constrast (stone protocol)
• the imaging modality of choice for suspected
ureterolithiasis
• Both abdomen and pelvis are scanned (because the stone,
hydronephrosis and structure could be anywhere from the kidnety
to the bladder)
• No IV or oral contrast – might obscure identification of the stone
what are CT Findings of Ureterolithiasis
• Hydronephrosis
• Hydroureter
• Perinephric stranding
• Note
– Location of stone
– Size of the stone
what is the Imaging for Suspected Acute Appendicitis
• CT Abd/Pelvis with IV and oral contrast is first line.
• US or MR can be performed if concerned about radiation exposure.
• In children and pregnant patients, US of the RLQ should be first line
imaging.
what are CT Scan Findings of Acute Appendicitis
- Appendiceal wall thickening and enhancement - diameter > 6 mm
- Pericolonic fat inflammatory changes (also called “fat stranding”)
- Pericolonic fluid - free or loculated
- Free intraperitoneal gas if perforated
- +/- appendicolith
when is EGD the test of choice?
– Imaging test of choice for gastritis, PUD, GERD
what is EGD diagnostic and therapeutic for?
- Upper GI Bleed
- Choledocholithiasis
- Esophageal narrowing or foreign body
when is Flexible sigmoidoscopy used?
screening test for colon cancer
what is Flexible sigmoidoscopy diagnostic and therapeutic for?
• lower GI bleed
what imaging would you use for
• Bowel (infection, inflammation, obstruction, cancer)
– Ct Abd/Pelvis with IV and oral contrast
what imaging would you use for
Solid organs (injury, infection, cancer)
– Ct Abd/Pelvis with IV contrast
what imaging would you use for
Gallbladder
Ultrasound; If suspect Choledocholithiasis then MRCP or ERCP
what imaging would you use for
GYN
– US if pregnant or suspect torsion or cyst
– Ct with contrast if suspect cancer or abscess
what imaging would you use for
Male GU
– US for torsion, Ct with contrast if suspect cancer or infection (Fournier’s, abcess)
what imaging would you use for
• Kidney/Ureter/Bladder
– Ct without contrast if suspect stone, with if suspect cancer, infection then IV contrast
what imaging would you use for
• Abdominal Vasculature (aorta, mesenteric arteries)
– Ct Abd/Pelvis with IV contrast
what imaging would you use for
• Appendicitis
CT abd/pelvis with IV and Oral contrast
– US first if child or pregnant
what imaging would you use for
• Biliary Colic/Gallbladder pathology
– US RUQ
what imaging would you use for
• Renal Colic (Kidney stone/ureterolithiasis)
– CT abd/pelvis without contrast (stone protocol)
– US if chronic kidney stones, pregnant or child
what imaging would you use for
• Abd Trauma
– FAST scan initial screen for interperitoneal blood
– Ct Abd Pelvis with IV contrast only is gold standard
what imaging would you use for
• Vasculature (AAA, Aortic Disection, Mesenteric Ischemia)
– Ct Abd/Pelvis with IV contrast
• If uncertain etiology then CT Abd/Pelvis with IV and Oral Contrast
– Gives you the most overall information
