Procedures Flashcards
What does the Sylvian fissure divide?
The frontal and parietal lobes from the temporal lobe
What landmark is used for brain imaging?
Nasion
What sequence is best for demonstrating hemorrhagic infarct?
Gradient echo
What does contrast in DWI depend on?
- Degree to which molecular mobility is impaired (water restriction)
- Sensitivity of the sequence to Brownian motion
- Direction of water diffusion
What is Bells Palsy?
Dysfunction of cranial nerve VII (facial nerve) results inability to control facial muscles on affected side
Which plane best demonstrates median nerve?
Axial
Where is Wilms’ tumor found?
Pediatric kidney
Define hemochromatosis and how is it best demonstrated on mri
Disorder where too much iron builds up in the body. T2* gradient echo sequences needed
Branches of abdominal aorta from superior to inferior
Celiac, superior mesenteric, renal, inferior mesenteric
Which vessels form the hepatic portal vein?
Superior mesenteric and splenic veins. Blood also received from inferior mesenteric, gastric, and cystic veins
What veins join you form inferior vena cava?
Common iliac veins
Where does the Azygos vein drain into?
Superior vena cava
MR angiography uses which kind of pulse sequences?
Gradient Echo
The _____ of blood is responsible for the bright blood signal in time of flight MR angiography
Flow
Which MR angiography technique has a scan time short enough to complete an abdominal study in a single breath hold?
Contrast enhanced
Flow before an area of stenosis is…
Laminar flow
Vortex flow
Blood flow that is initially laminar, then intersects a vessel stenosis or stricture, becoming high velocity central flow and spiral near the walls of the vessel
An imaging option used to compensate for CSF flow in the cervical spine would be:
Gradient moment nulling
What is the best method to evaluate cardiac infarction?
Perfusion cardiac imaging
Common problems in DWI
Sensitivity to magnetic susceptibility
Bulk patient motion
Low SNR
Characteristics of perfusion imaging
Establish vascularity of given process
Compare vascularity at particular point with internal reference
Unit of measurement: rCBV relative cerebral blood volume. Proportional to degree of neovascularity or capillary density
Uses of perfusion imaging
Differentiating tumor from non tumor, and primary brain neoplasm from secondary lesions
Glioma grading
Stereotactic biopsy guidance
Differentiating tumor recurrence from radiation necrosis
Protocol for brain perfusion imaging
Ultra fast gradient echo sequence with bolus injection IV gadolinium
Exponential time curves generated on separate workstation, with multiple ROIS generated to calculate specific rCBVs
NAWM (normal appearing white matter) established as control and area of pathology/edema compared to determine vascularity
DSC
Dynamic susceptibility contrast, better known as T2* gradient echo perfusion
DCE
Dynamic contrast enhancement, basic T1 perfusion imaging (pituitary or prostrate dynamic sequences) longer acquisition time than DSC
Final result of spectroscopy study
Spectrum if specific metabolites detected
For pituitary tumors is important to scan ________ because tumors appear as _______ signal intensity compared to the enhanced pituitary gland
Rapidly/low
