Abdomen/Pelvis Flashcards
What is the peritoneum? What is the difference between males and females?
membranous sac containing most anteriorly placed abdominal and pelvis organs. males have a closed sac, females have one that opens inferiorly through the fallopian tubes, uterus, and vagina
What organs are in the retroperitoneum?
duodenum, kidneys, ureters, bladder, pancreas, uterus, prostate
What is the amount of PO contrast and delay before scanning for:
- distal intestines
- proximal intestines
- prox int & stomach
- 450 mL, 90-120 minutes
- 300-450 mL, 30 minutes
- 300-450 mL, 30 minutes, and extra 150-250 mL just prior to scan
What is the normal HU range for an un-enhanced liver?
45-65 HU; slightly more dense than the spleen
T/F: Most common hepatic malignancies are metastases. They appear hypodense.
True
What is the most common malignant neoplasm of the liver and how do they appear on a contrasted study?
hepatocellular carcinomas; they appear isodense. because of this, HCCs require a multiphase study
What is steatosis?
fatty liver. HU measuring at least 10 lower than that of the spleen
For the liver, when is the arterial phase of contrast enhancement, and what is best demonstrated?
25-35 seconds; hypervascular tumors supplied by the hepatic artery are enhanced while the rest of the hepatic parenchyma are not
For the liver, when is the portal venous phase of contrast enhancement, and what is best demonstrated?
60-70 seconds; liver parenchyma and hypovascular lesions are well enhanced
For the liver, when is the early arterial phase of contrast enhancement, and what is best demonstrated?
15-20 seconds; good for demonstrating hepatic arterial supply without enhancing hypervascular lesions
For the liver, when is the delayed phase of contrast enhancement, and what is best demonstrated?
5-20 minutes; hemangiomas become isodense
What is an FNH?
focal nodular hyperplasia; benign, vascular lesion of the liver; usually forming on the surface of the liver and appears with a hyopense central scar until delayed imaging when it will appear hyperdense
What is cholecystitis and how does it appear on CT?
inflammation of the gallbladder; CAN appear as contrast-enhanced and thickened wall, with distension, and gallstones
What is the HU measurement of the non-enhanced spleen?
40-60 HU, roughly 10 less than that of the liver
What is the preferred phase to scan the spleen?
portal venous phase
T/F: The spleen is the second most injured abdominal organ from blunt trauma.
False, spleen is first, liver is second
How do pancreatic tumors appear?
hypodense compared to the rest of the contrast enhanced pancreas.
When is the pancreatic phase?
35-45 seconds, also called “delayed arterial phase”
What are the two most important reasons to scan the pancreas?
(1) to find and assess neoplasms and (2) what surrounding vessels are affected
What is the HU measurement of the adrenal glands?
25-40 HU; similar to that of muscle
Which 3 phases are typically scanned for the adrenal glands? Why?
- pre-contrast: to show benign masses (<10HU)
- portal venous: normal filling study
- delayed (10-15 min): tumor characterization
What slice thickness is used for a CT of the adrenals?
0.5-2.0 mm; the thinner the better
The epithelial lining of the urinary tract is called what? What common renal malignancy originates here? Which contrast phase best demonstrates this lining?
urothelium; transitional cell carcinoma; excretory phase
What is the recommended slice thickness for CT of the genitourinary system?
3-5 mm
Name the three primary malignancies that metastesize to the kidneys.
- lung
- breast
- colon
Name the three phases of contrast enhancement of kidneys and what each demonstrate.
- corticomedullary phase: late arterial: 30-40 sec. best shows cortex and renal veins
- nephrographic phase: 70-90 sec. best shows renal parenchyma
- excretory phase: 3 minutes. best shows calyces, renal pelvis, ureters, and bladder
Define abscess.
collection of pus caused by infection or inflammatory process
For what conditions is IV contrast indicated for the bowel?
bowel wall thickening, mass lesions (diverticulitis), inflammatory processes, and vascular perfusion abnormalities like bowel ischemia
Define ileus.
an area of intestine that has lost normal contractile motion, resulting in an obstruction
For a study of the gastrointestinal, what is the recommended delay for optimal IV contrast enhancement?
portal venous phase
What is a hydrocele of the testes?
an abnormal collection of fluid around a testicle
How do the seminal vesicles appear in CT?
as a bow tie posterior to the bladder
Which layer of the uterus enhances well after IV contrast?
myometrium; due to its highly vascular composition
What is an “Adnexa”? What is an example of one?
an appendage of an organ, like the fallopian tubes of the uterus.
The aorta bifurcates into the _______ arteries at the vertebral level of ____.
common iliac; L4
The femoral vein is located _____ to the iliac vein.
medially (and slightly posterior)
What percent ofa barium-sulfate solution is used in a CT Enterography?
1-3%
What tumor is also called a nephroblastoma? What age group does it affect?
Wilms tumor; pediatric ages 1-5
