imaging the abdominal viscera Flashcards
what are the 4 types imaging?
- x ray/fluoroscopy
- ultrasound (US)
- computed tomography (CT)
- magnetic resonance imaging (MRI)
what are the 3 planes of imaging?
- axial
- coronal
- sagittal
what are the 2 main types of image sequencing in MRI?
T1 and T2
what is the difference between T1 and T2 image sequencing of MRI?
- T1 = fluid is black
- T2 = fluid is white
what does contrast do?
increases contrast resolution
how is contrast given?
intravenously or enterally
what are the pros of x-ray?
- cheap
- quick
- easy for patient
- high spacial resolution (good for bone)
- low radiation dose
what are the cons of x-ray?
- poor contrast resolution (poor for soft tissue)
- planar imaging (superimposes structures)
what are the pros of CT?
- quick
- widely available
- cross sectional images
- high contrast resolution (good for soft tissue)
what are the cons of CT?
- radiation dose
- IV contrast risks
what are the pros of ultrasound?
- cheap
- quick
- no radiation
- cross sectional images
- US guided interventions
what are the cons of ultrasound?
- saved images are only a snapshot of examination (report operator dependent)
what are the pros of MRI?
- contrast resolution
- specific applications
- no radiation
what are the cons of MRI?
- limited availability
- patient experience (duration, claustrophobia)
- expense
- magnet/contrast risks
how is the liver divided into hepatic segments?
- portal vein horizontally
- hepatic vein vertically
how do you image the abdomen?
- bowel (hollow viscera): stomach, small bowel, large bowel
- x-ray: a goof first test for bowel
- CT and MRI increasingly useful
where do you position the imaging device for the stomach?
- left upper quadrant
- funds directly under left hemidiaphragm
- obliquely orientated
where do you position the imaging device for the small bowel?
central abdomen
where do you position the imaging device for the large bowel?
peripheral: the large bowel frames the small bowel
what is contained in the stomach?
fluid and air
what is contained in the small bowel?
fluid and air
what is contained in the large bowel?
faeces (liquid/hard)
what is the mucosal/wall pattern for the stomach?
rugal folds
what is the mucosal/wall pattern for the small bowel?
- encircling valvulae conniventes: more widely spaced in ileum
- wall pattern can be effaced if distended
what is the mucosal/wall pattern for the large bowel?
- haustral folds interspaced with Plicae
- wall pattern can be effaced if distended
what is the size of the stomach?
variable
what is the size of the small bowel?
<3cm diameter
what is the size of the large bowel?
<6cm
<9cm for the caecum
