Radiology Flashcards
Why arent X rays used for digestive organs
Limited use for soft tissues as they have similar radiodensities and tissues are superimposed on each other
Air in abnormal places can indicate pathology
When/where is contrast agent used
For x-ray studies:
Introduce into cavities (e.g. gut)
Inject into blood vessels to to outline blood distribution
Gut studies
* Barium Sulphate
Vascular agents for injection
* Iodinated compounds (X-Ray and CT) Gadolinium-based compounds
(MRI)
* Excreted by kidneys
benefits of CT over Xray
All tissues NOT superimposed on each other as with x-ray
Change viewing parameters to accentuate pathology
3D data so multiplanar Can reformat viewing plane
CT contrast enhancement:
Why use contrast in CT
How to tell if contrast has been added
Most soft tissues have “water” density (so all look the same)
To make sure; look at kidneys. Kidneys bright because excreting Contrast agent
What organ or structure would be very bright in CT with contrast added through IV
Aorta
T2 vs T1 MRI differene
T2: Fluid/water bright
T1: Fat is bright
Label the anatomy in T11 scan
Lecture Slide
Label anatomy in T12 scan
Lecture Slide
Patient presents with abnormal liver function tests,
jaundice or for staging of cancer or trauma
What scans do you use first? why ? other scan options post first
- Ultrasound
- Suitable for liver imaging, fast, no radiation
Other modalities:
CT (staging) and
MRI (lesion characterization)
Label normal liver US
Lecture Slide
Key feature on heaptic metastases US
Regions of increased echogenicity (due to more BV and more interfaces for the US to reflect back on)
Lecture Slide
What does alcoholic liver disease cirrhosis look like on CT scan
- further test?
Nodular replacement of tissues
liver becomes stiff
MR elastography
Determines:
- The stiffness of the liver - The degree of fatty replacement in the liver
Liver infections (abcesses, hydatid cysts) look like on CT
Lecture Slide
Gallstone appearance on XRAY
- what scan is most prefered
- Look at images comapring the two
X-ray – often normal Occasionally radiopaque
US is Imaging modality of choice
Gallbladder– cholecystitis
- WHat do u see on scan?
Increased gallbladder wall thickness from oedema and inflammatory changes
Fat stranding/“Mucky fat” sign
Lecture Slide
gall bladder – MRI cholangiogram
Purpose
To detect cause of bile duct obstruction: stones,
tumour (pancreas, cholangiocarcinoma)
Pancreas Bile duct obstruction:
-what does it look like on CT
Lecture Slide
Pancreas tumor
- examples on lecture SLide
Lecture Slide
Pancreas – Acute pancreatitis
- feature on CT
Causes of Acute pancreatitis
Sudden inflammation of the pancreas
Causes
Gallstone impacted in
the common bile duct beyond the point where the pancreatic duct joins CBD
Heavy alcohol use; Trauma; mumps (kids)
- massively enlarged pancreas and mucky fat
Mucky fat great indication for
something inflammatory going on in abdomen
Pancreas – chronic pancreatitis feature
Extensive calcification (appear as white dots)
Lecture Slide
Spleen concerns, first mode of scans?
Ultrasound and CT both first line modalities for investigation
Feature on Splenic trauma
Lots of blood (fluid)
Lecture Slide
Splenomegaly
- feature on CT
Lymphadenopathy
-feature on CT
grossly enlarged
Lymph nodes grossly enlarged by aorta
Best scan type for adrenals
-why are they challenging to see
CT or MRI
they are so SMALL
Adrenal cancer typically where?
CT is used to?
Staging Ct to detect cancer spread will include chest and liver including adrenals
Primary in:
Lung
Colorectal Breast
Pancreatic
Feature of gastric cancer
Focal thickening of gastric wall
What does Crohns look like on CT
In Terminal ileum
Thickening of bowel wall
* Inflammatory changes in
fat stranding and mucky fat
- CT good method to study extent of disease
Colonic polyps on CT
Lecture Slide
Colon cancer key feature
Apple core sign in bowel
Causes for bowel obs
- Hernias
- Tumors
- Intussusception
Lecture Slide
What does free air in abdoemn look like and causes
- Trauma
- Bowel perforation
Lecture Slide
How to tell if the bowel has perforation
IF Both sides of bowel wall visible = perofated
