Imaging of the nervous system Flashcards
Feature that is better appreciated on CT than MRI
Calcification
Injected material used in contrast CTs
Iodine containing contrast agents
Brain area where lesions are poorly visualised on CT
Posterior fossa
Units used to measure the magnetic field strength of MRI magnets
Tesla
Type of nuclei used in MRI due to the way their axes lie
H1
Environmental aspect that determines the rate at which H1 nuclei realign
Degree of water content
Tissue type where H1 nuclei realign quickly in MRI
Fat
Tissue type where H1 nuclei realign slowly in MRI
Water
Two pulse sequences used in MRI
T1 and T2
Pulse type in MRI in which the pulses are brief
T1
Environments which are overemphasised on T1 MRI images
Hydrophobic environments e.g. fat is white
Use of T1 images on MRI
Normal brain structure
Contrast agent possible on T1 MRI images
Gadolinium-DTPA
Environments which are overemphasised on T2 MRI images
Hydrophilic areas e.g. CSF is white
Use of T2 images on MRI
Show brain pathology
Use for protein density sequences on MRI
Show periventricular structures
Images seen on FLAIR MRI results
T1 images are inverted and added to T2 images to double the contrast seen
Uses for FLAIR images on MRI
Sclerosis of the hippocampus caused by temporal lobe epilepsy
Areas of abnormal metabolism in neurodegenerative disorders
Absolute contraindications for MRI
Pacemakers
Implants of ferromagnetic materials
Colour of infarct on CT
Dark
Colour of infarct on T1 MRI
Dark
Colour of infarct on T2 MRI
Bright
Colour of bleed on CT
Bright
Colour of bleed on MRI (T1 and T2)
Bright unless too old or too new
Colour of tumour on CT
Dark
Colour of tumour on T1 MRI
Dark
Colour of tumour on T2 MRI
Bright
Colour of MS plaque on CT
Dark
Colour of MS plaque on T1 MRI
Dark
Colour of MS plaque on T2 MRI
Bright