25 y/o male presents to the ER with head trauma. Diagnostic test of choice?
CT brain without contrast
Which imaging modality of the brain causes no radiation exposure to the patient?
MRIq
55 y/o female presents to the ER with unilateral weakness, onset 30 minutes ago. Initial diagnostic test of choice?
CT brain without contrast
What are the imaging options for the brain?
- CT
- MRI
CT
- high radiation dose to patient
- quick examination
- expensive
- mainstay and test of choice in the initial imaging of the brain in trauma and stroke like symptoms (WITHOUT CONTRAST)
What is the mainstay and test of choice in the initial imaging of the brain in trauma and stroke like symptoms (without contrast)?
CT
What kind of tests would you do a CT without contrast?
Trauma, stroke-like symptoms
Used in assessment of altered mental status, headache, dizziness, vertigo, evaluation of the paranasal sinuses
CT brain with contrast
- not performed in initial assessment
- used in assessment of abnormal enhancement patterns such as masses, vascular abnormality. MRI also used in similar capacity. MRI more sensitive than CT
What is used in assessment of abnormal enhancement patterns such as masses, vascular abnormality such as avascular malformation?
CT with contrast
which is more sensitive? MRI or CT?
MRI
What parts of the brain anatomy should you see in a CT of a healthy brain?
- midline flax
- frontal horns of lateral ventricles
- third ventricle
- basal cistern
- skull
- scalp
What part of the brain would you need to scan if someone complained of vision problems?
Occipital
MRI
- no radiation
- very expensive
- takes longer than CT therefore motion sensitive
- DWI: most sensitive sequence in radiology in the assessment of acute ischemia
- typically done with and without contrast
When do you typically do MRI?
After you do a CT and it shows something abnormal
TPA
- very dangerous
- make sure they aren’t bleeding anywhere
- extreme blood thinner
- not goof to look for blood
Which takes longer? MRI or CT?
MRI
DWI
Most sensitive sequence in radiology in the assessment of acute ischemia
Contraindications of MRI
-pacemaker, radioplate foreign bodies, claustrophobia
Welders and MRI
Must do an xRay on eyes to make sure there is no metal pieces lodged in eye before getting into MRI so as to not rip through optic nerve and ophthalmic artery
What contrast used in CT?
Iodine contrast
What contrast used in MRI?
MGd
What is good for people who are allergic to contrast?
MGd. It contains gadilium. Very rare to have allergy with this
Imaging options in the assessment of the cerebral vasculature
- CTA
- MRA
- ultrasound
- digital angiography
CTA contraindications
Allergy, renal insufficiency
How do you get around patients having an allergy to iodine when you must do a CTA?
Harvard Prep hours before CT
How do you get around renal insufficiency when a CTA must be done?
Hydrate pt well or dialysis
What kind of images can you get with CTA?
-axial, coronal, sagittal, reformatted
What is the number one place that saccular aneurysms occur?
Anterior communicating artery (posterior is second)
MRA
Good to assess vascular without contrast
Contraindications of MRA
Same as MRI
Time of flight sequences in MRA
Allows assessment of the vasculature WITHOUT using contrast
Ultrasound
Used in the assessment of vascular flow within the vertebral arteries
-shows antegrade vs retrograde flow
What direction should bloodflow be?
Antegrade
When will you see retrograde blood flow in US
In subclavian steal syndrome
Digital angiography
- High radiation dose
- abnormalities such as aneurysms/AVM can be fixed at time of angiography
Contraindications of digital angiography
-allergic to contrast, renal insufficiency
Complications of digital angiography
Vascular trauma, pseudoaneurysm, small risk of death (coils are sharp)
Imaging options of the spinal column
- CR
- CT
- MRI
What is the test of choice in the initial assessment of trauma to the neck/ c-spine, thoracic spine and lumbar spine?
CR because of low radiation dose and cheap
If CR negative and patietns symptoms persist and/or clinical suspicion high for abnormalities what’s the next test of choice?
Generally CT (especially ER setting) MRI (if one wants to rule out cauda equine syndrome)
Imaging options of the spinal cord
- MRI (best)
- CT myelogram
CY myelogram
Flip patient upside down, but don’t let it pass the cervical part of spine. Will cause awful headache if it gets in brain
