Week 9: Head Flashcards
Generally speaking, what is the patient position for MRIs of the head and brain?
Supine, headfirst
Generally speaking, what is the body position for MRIs of the head and brain?
With mid-saggital line perpendicular to the alignment light
Generally speaking, what is the landmark used for MRIs of the brain and head?
Nasion
Generally speaking, what receiver coil is used for MRIs of the head and brain?
8 channel brain coil
Where should the patient be supported during MRIs of the brain and head?
Cushions to support the sides of the head and lumbar.
What kind of hearing protection should patients have during MRIs of the brain and head?
Earplugs
What sequence options should be utilized during MRI brain protocols?
- Flow compensation.
- Inferior saturation band.
What are the nine protocols for MRIs of the brain?
- Sagittal T1.
- Axial diffusion. (DWI.)
- Axial FLAIR.
- Axel MPGR.
- Axial SWI.
- Axial T2.
- Axial T1, pre-contrast.
- Axial T1, post-contrast.
- Coronal oblique T2
Generally speaking, what is the sagittal T1 protocol used for all MRI studies of the head and brain?
To view sagittal midline structures
What does the axial DWI MRI brain protocol check for?
Restricted diffusion/stroke, which presents as an area of brightness within the first 48 hours
What is visualized during the axial FLAIR MRI brain protocol?
Any bright plaques, which would suggest stroke or multiple sclerosis
The axial MPGR protocol of an MRI brain is used in the evaluation of what?
Any possible blood or hematoma caused by trauma
Which MRI brain protocol is known as the “NFL concussion protocol”?
Axial SWI
What anatomy is best viewed on an axial T2 protocol of an MRI brain?
Posterior brain, brainstem, and fossa
When performing axial T1 pre-and post contrast, the technologist ensures the scans are set up the exact same way. True or false?
True
Contrasted axial T1 studies during an MRI brain are used to visualize what?
Vasculature, masses, lesions, and infections
Coronal oblique T2 images during an MRI brain allows for a cross-sectional view of the _______________.
Hippocampus
The lateral sulcus is also known as the what?
The Sylvia Fissure
What is the Sylvia fissure?
A noticeable fissure that separates the parietal and temporal lobe of the cerebrum
Where does the caudate nucleus lie in the brain?
Adjacent to the anterior horn of the lateral ventricle
What pea-sized, conical mass of brain tissue controls melatonin secretions?
The pineal gland
What are the names of the three meninges?
- Pia mater.
- Arachnoid.
- Dura mater.
What structure connects the occipital tubercle to the mastoid air cells?
The transverse sinus
What is the purpose of the Aquaduct of Sylvius?
To connect the third and fourth ventricles
What is the cavelike structure found along the midline of the brain and connects the right and left hemispheres?
The corpus callosum
What are the three structures of the brainstem?
- Midbrain.
- Pons
- Medulla oblongata.
Which cranial nerve is the olfactory nerve?
CN I
What is the function of CN I?
Smell
What is the function of CN II?
Sight
Which cranial nerve is the optic nerve?
CN II
Which cranial nerve is the oculomotor nerve?
CN III
What is the function of CN III?
Pupil constriction and dilation
Which cranial nerve is the trochlear nerve?
CN IV
What is the function of CN IV?
Movement of superior oblique eye muscles
Which cranial nerve is the trigeminal nerve?
CN V
What is the function of CN V?
Movement of facial muscles
Which cranial nerve is the abducens nerve?
CN VI
What is the function of CN VI?
Lateral eye movement
Which cranial nerve is the facial nerve?
CN VII
What is the function of CN VII?
Taste and facial movement
Which cranial nerve is affected by Bell’s palsy?
Facial nerve
Which cranial nerve is the auditory vestibulocochlear nerve?
CN VIII
What is the function of CN VIII?
Hearing and balance
Which cranial nerve is the glossopharyngeal nerve?
CN IX
What is the function of CN IX?
Control of the pharynx, tympanic membrane, and taste
Which cranial nerve is the vagus nerve?
CN X
What is the function of CN X?
The peripheral nervous system and gastrointestinal tract
Which cranial nerve is the spinal accessory nerve?
CN XI
What is the function of CN XI?
Head and shoulder movement
Which cranial nerve is the hypoglossal nerve?
CN XII
What is the function of CN XII?
Speech and swallowing
What is the Arnold Chiari malformation?
The inferior extension of the cerebellar tonsil through the foramen magnum
There are many clinical concerns for an MRI brain, what are 10?
- Brain tumors.
- Brain lesions.
- Stroke.
- Head trauma
- Headaches.
- Multiple sclerosis.
- Hormonal disorders
- Congenital disorders
- Meningitis
- Arnold chiari malformation
What does IAC stand for in reference to MRI anatomy?
Internal auditory canal
When setting a patient up for an MRI IAC, the positioning landmark is at the level of the nasion. What are another two reference points?
- The external acoustic meatus (ears)
- The level of CN VII and VIII
What sequence options should be utilized during MRI IACs?
- Flow compensation.
- Inferior saturation band.
What are the 6 MRI IAC protocols?
- Sagittal T1.
- Axial T2.
- Axial T1, pre-contrast.
- Coronal T2.
- Axial fiesta/EPI.
- Axial T1, post-contrast.
What is the approximate thickness of each slice during an MRI IAC and why?
~2mm; very thin slices are required to view such small anatomy like the IAC
What is the purpose of the coronal T2 protocol of an MRI IAC?
This beneficial plane checks for proper IAC positioning
The axial fiesta/EPI protocol of an MRI IAC is a ____ _________ technique to view even thinner slices (~___ mm) of the IACs.
3-D volume; ~1mm
The axial T1 pre-and post-contrast protocols of an MRI IAC are used to evaluate the presence of what?
Pathology
What does the cochlea look like, where is it found, and what does it do?
- A shell-like structure.
- Medial to the tympanic membrane.
- Transfers sound waves to CN VIII
What is a vestibular/acoustic schwannoma?
A slow growing tumor due to overproduction of Schwann cells
What are five clinical concerns for an MRI IAC?
- Vestibular schwannoma.
- Vertigo.
- Tinnitus.
- Equilibrium disturbances.
- Hearing loss.
Are cochlear implants MRI safe?
No
What three sequence options are utilized during an MRI pituitary?
- Flow compensation.
- Inferior saturation band.
- No phase wrap (which means no over-sampling)
Pituitary exams usually use dynamic imaging techniques. True or false?
True
What are the six protocols of an MRI pituitary gland?
- Sagittal T1.
- Sagittal T2.
- Sagittal T1 thin, pre-contrast
- Coronal T1 thin, pre-contrast.
- Sagittal T1 thin, post contrast.
- Coronal T1 thin, post contrast.
What is the sagittal T2 protocol of an MRI pituitary used for?
To visualize any abnormal signal intensities
Approximately how thick are the slices during the sagittal and coronal T1 thin protocols of an MRI pituitary?
~1.8 mm
Approximately how big is the field of view during the sagittal and coronal T1 thin protocols of an MRI pituitary?
8-10 cm
What is the purpose of the sagittal and coronal T1 thin, pre- and post-contrast protocols of an MRI pituitary?
To visualize the absorption of gadolinium by the pituitary gland in two different views, frontal (coronal) and from the side (sagittal)
THIS small gland makes growth hormones and sits within the sella turcica.
The pituitary gland
What is acromegaly?
A rare disease caused by the uncontrolled, overproduction of gH in the pituitary gland after puberty.
What is the name of the hormone produced by the pituitary gland that stimulates maturation of follicle development in women?
Follicle stimulating hormone (FSH)
What is the infundibulum and what two structures does it connect?
A small, stalk-like structure; the hypothalamus and the posterior pituitary gland
What are five clinical concerns for an MRI pituitary?
- Acromegaly.
- Early onset menstruation.
- Pituitary tumors.
- Estrogen levels.
- Progesterone levels.
What three sequence options are utilized during protocols of an MRI orbits?
- Flow compensation
- No phase wrap.
- Inferior saturation band.
What are the seven protocols of an MRI orbits?
- Sagittal T1.
- Axial T2.
- Axial T1 thin, pre-contrast.
- Axial thin IR.
- Coronal T1 thin, pre-contrast.
- Axial T1 thin, post-contrast.
- Coronal T1 thin, post contrast.
What two things are observed during the axial T2 protocol of an MRI orbits?
- The long axis of the optic nerve.
- The ocular dimensions.
The axial thin IR protocol of an MRI orbits can also be what?
T1 fat sat
As discussed in previous weeks, T1fat sat and IR imaging are fat suppression techniques. What is the purpose of utilizing fat suppression techniques during the axial thin IR protocol of an MRI orbits?
With the suppression of surrounding fat, better visualization of the optic nerve is achieved
The axial and coronal T1 thin, pre-and post contrast protocols of an MRI orbits are used to evaluate what?
The absorption of gadolinium on two different cross sectional planes.
What’s the difference between aqueous and vitreous humor?
Aqueous is found anterior to the lens, and vitreous is found posterior.
What is glaucoma?
The condition in which an increase in aqueous and/or vitreous humor causes painful pressurization of the eyeballs.
Through what structure is the optic nerve connected from the back of the eye to the brain?
The optic chiasm
Where is CN III located?
Between the posterior eye and the brain
Rods allow vision adjustment in _______ environments.
Dark
Cones allow vision in both dark and light environments. True or false?
False; cones are used in light, while rods in dark
What is macular degeneration?
An eye disease that causes vision loss
What are four clinical concerns for an MRI orbits?
- Retinal detachment.
- Ocular masses.
- Glaucoma.
- Macular degeneration.
Patient with scleral buckle surgical repair for retinal detachment are considered MRI safe. True or false?
True
What does COW refer to, in regards to brain anatomy and MRA?
The circle of Willis
What sequence options are utilized during an MRA COW?
- Flow compensation.
- Superior saturation band (to nullify venous flow)
What are the two protocols for an MRA COW?
- Sagittal T1.
- Axial 2-D TOF with Asset
During the axial 2-D TOF with asset protocol of an MRA COW, the technologist should plot slices as _______ as possible.
Straight
From where to where are the slices plotted during an axial 2D TOF with asset protocol of an MRA COW?
Slices are plotted inferior to superior; from the Foramen Magnum to the top of the corpus callosum.
What is the average field of view for an MRA and MRV brain?
22 cm
What is the average slice thickness for an MRA brain?
1.2 mm
What is the average matrix size for an MRA and MRV brain?
256x160
What is the average TR for an MRA brain?
23 s
What is the average flip angle for an MRA brain?
25°
What is the anterior aspect of the COW composed of?
The most superior aspects of the right and left internal carotid arteries
What is the posterior aspect of the COW composed of?
The basilar artery
What is the name of the artery that is composed of the conjoining right and left vertebral arteries?
Basilar artery
Where do the vertebral arteries pass through?
Both the foramen Magnum and the vertebral foramina
Is contrast used to perform an MRA of the brain? Why?
No, 2-D time of flight imaging is used instead
What are two clinical concerns for an MRA brain?
- Cerebral aneurysm.
- Cerebral stenotic disease.
What are the three protocols of an MRV brain?
- Sagittal T1.
- Axial T2.
- Sagittal – oblique
What sequence options should be utilized during protocols of an MRV brain?
- Flow compensation.
- Inferior saturation band.
Where does the technologist plot the slices during an axial T2 protocol of an MRV brain?
Along the inferior margins of the corpus callosum
The sagittal-oblique protocol of an MRV brain can be TOF or PCA. True or False?
True, depends on facility protocols.
During the sagittal-oblique protocol of an MRV brain, slices are plotted sagittally first. Then, the entire plot of slices is slightly obliqued _______ from the midline of the brain.
10°
During the sagittal-oblique protocol of an MRV brain, the technologist must ensure to cover the right and left _______ ________ to include all lateral ______ flow.
Temporal lobes; venous
What is the purpose of the 10° angulation during the sagittal-oblique protocol of an MRV brain?
To reduce any in-plane saturation effects
What is the average sliced thickness of an MRV brain?
1.5 mm
What is the average flip angle for an MRV brain?
70°
What is the superior sagittal sinus and where does it travel?
A large superficial vein; along the superior and posterior border of the brain
The superior sagittal sinus bifurcates laterally at the base of the brain. This area is known as what.?
Transverse Venous sinus
Cerebral venous thrombosis is also known as what?
Venous sinus thrombosis
Justly named, cerebral venous thrombosis refers to the formation of blood clots in the venous structures of the brain. What does this cause?
Obstruction of blood flow and, ultimately, infarction
What is arteriovenous malformation (AVM)?
The abnormal connection between arterial and Venous vascularity
What are two clinical concerns for an MRV brain?
- Cerebral venous thrombosis.
- Arteriovenous malformation.
What can mimic stenosis in the brain when utilizing 2D TOF imaging?
In-phase suppression of Venous structures
Given that pathology can be mimicked in 2-D TOF imaging, what two actions can confirm true data?
- Reviewing source data.
- Use of PCA instead of ToF