Final MRI Protocols Flashcards
What is included in patient preparation for any MRI examination?
Surgery?
Implants? When, where?
Shrapnel?
Pre-cannulation?
Changing into a gown
Remove make-up
Secure or remove piercings and jewellery
What is a routine brain sequence?
3 plane localiser - at isocentre, 5 images, T1FS
Sagittal T1 - for midline, full head ant. and post. to temporal bones, 4-5mm slices
Axial T2 - survey pathologies and fluid structures, superior skin edge to foramen magnum, 4-mm slices
Axial FLAIR - survey pathologies especially grey and white matter, superior skin edge to foramen magnum, 4-5mm slices
Axial DWI - gold standard for strokes, superior skin edge to foramen magnum, 4-mm slices
Axial Gradient - for magnetic susceptbility (blood or calcium products), superior skin edge to foramen magnum, 4-5mm slices
What is the protocol for a brain ?tumour ?
Routine brain
Axial T1 pre contrast with hand injection of Gad
Axial T1 + C
Coronal or sagittal T1 C - orthogonal view
Optional: 3D T1 + C- for pre-operative planning or intra-operatively
Name an operation that would need further discussion if listen on an MRI safety questionnaire?
Brain surgery, ear surgery, brain aneurysm treatment, insertion of active implant
What are the 5 common routine brain sequences?
Sagittal T1, axial T2, FLAIR, DWI, GRE
A FLAIR sequence in the brain is very good at differentiating between —- and —-
Grey and white matter
A GRE sequence in the brain is sensitive to what blood breakdown product?
Haemosiderin
What are the common post contrast brain sequences?
Axial T1+C
What are the common post contrast brain sequences?
Axial T1+C and Cor T1+C
What is TOF MRA?
Time of flight MR angiography
Does not use IV Gad
Is a 3D sequence
Using MIP
Good for large blood vessels
What is MRV?
MR venography
Using IV Gad
Can be added to routine brain
Is a 3D sequence
Using MIP
Good for large blood vessel
What sequence should be used for the IAMs?
T2 thin slice
May be 2D or 3D
Done over internal and external AM
Axial and coronal views
When a referral says ?acoustic neuroma, what MRI sequences should be performed?
A routine brain scan and IAMs sequence
What does an IAMs sequence demonstrate?
Acoustic neuroma
7th and 8th cranial nerves
What sequences should be done for the pituitary?
T1 coronal and sagittal
T2 coronal and sagittal
Post contrast T1 coronal and sagittal
What are some limitations of a pituitary sequence?
A small FOV mean result in phase wrap
Therefore, use a large FOV and focus on the smaller ROI
What sequences should be done for a referral with ?microadenoma ?
T1 coronal and sagittal
T2 coronal and sagittal
T1+C coronal and sagittal
Dynamic post contrast coronal
What is DTI used for?
Diffusion tensor imaging shows the white matter tracts in the brain. It is used for mapping to aid in pre-op planning
What is the relationship between multiple sclerosis and MRI?
MRI is the gold standard for imaging MS
What is the relationship between tumour operations and MRI?
MRI may provide additional information or better pre-op planning for tumours
What sequences best visualise MS?
T2 FLAIR
What sequences best visualise a new stroke?
DWI will demonstrate the stroke with a high signal
ADC will demonstrate the stroke with a low signal
What sequence best shows mets?
T2 FLAIR
What is the appearance of metastatic melanoma?
T1 - hyper-intense secondary to haemorrhage or melanin
T2 - hypo-intense
T1+C - peripheral rim pattern enhancement or a diffusely heterogenous pattern
What sequence is good for demonstrating an aneurysm?
TOF MRA
A diffusion mismatch can indicate what pathology?
Stroke
What is a routine spine protocol?
3 plane localiser - at isocentre, 5 images, T1FS
Sagittal T2
Sagittal STIR (or T2FS)
Sagittal T1
Axial T2 (all regions)
Axial T1 (depending on hx/findings)
What is the scan range for the C spine?
Laterally to include just beyond vertebral bodies, sup. and inf. at least 1 vertebral body (C2-T1). And ant. to post. to ensure anatomy is at the centre of the FOV
11-15 slices with a 10-20% gap
PE direction is AP
What is the scan range for a thoracic spine?
C6-L2 (include conus)
PE direction is AP
13-15 slices, 3-4mm thick with 10-20% gap
What is the scan range for a lumbar spine?
T11ish (conus) to S3
PE direction is AP
13-15 slices, 4mm thick with 10-20% gap
Occasionally, an Axial T2 lumbar spine will be done. What is the scan range for it?
Mid L3 to S1
PE direction is AP
19-30 slices, 4mm thick with 10-20% gap
What is the scan range for a full spine or cord in the sagittal plane?
Routine C and T spine coverage
15-17 slices, 3-4 mm thick with 10-30% gap
In a patient with scoliosis, what is the scan range for a full spine or cord?
4-5 sagittal sets angled across the spine at different levels
15-17 slices, 4mm thick with 10-20% gap
What is the scan range for a full spine or cord in the axial plane?
20-35 slices, 4mm thick with a 10-30% gap
What coil/s are required for spinal MRI imaging?
Spine array, posterior head coil, anterior neck element
What technique modifications can be done to position a patient with kyphosis?
Elevating the hips to tip the head back
What is the protocol for ?tumour in the spine?
Routine spine
T1 or T1FS pre contrast
Post contrast T1FS+C (sagittal and axial)
Why would a PD sagittal sequence be added for spine trauma?
To assess the posterior longitudinal ligament
Why would a GRE sagittal sequence be added for trauma/AVM
To survey for haemosiderin disposition for a bleed (or AVM)
What sequence will be added for a referral with ?cord infarct ?
A sagittal/axial DWI
A patient presented with significant pain, sudden leg weakness with a history of known malignant cancer. What protocol would be conducted for a ?cord compression ?
Full spine STIR in two FOV with axial T2
A common indication for post contrast spine imaging is —-
tumour or infection
What emergent clinical indication might require spine MRI?
Cord compression and epidural haematoma
A syrinx can be well visualised on — weighted image and appear on an axial image as an area of high signal shaped in an —–
T2
Oval/circle
