S1_L2_MSKI - 7-10 Flashcards
CORTICAL bones are __ in MRI
dark
bursa appears __ in t2
white
in t2 mri of the shoulder, it will look __
dark bc of fat conteent
ELEMENTS OF AN MRI SCANNER
magnet
gradient coils
rf coils
workstation
computer
Rests within a gantry large enough for the
human body and within the necessary receiver coils
magnet
The magnet has a field strength of around _ Tesla
0.3 – 3
1 Tesla = __ time the Earth’s magnetic field
20,000
_are also common where the patient is not fully surrounded by a magnet
Open scanners
how many gradient coils
3
Three gradient coils, one for each
__ are located within the _ of the MRI unit
orthogonal plane, core
The _ produce sequential
variations in the magnetic field that are used for providing _
gradient coils, spatial info
RF COILS serves 2 prposes
○ (1) Transmission of RF pulses that alter
the alignment of the protons
○ (2) Receive the signals emitted from the
protons
Send and receives radiofrequency, which
in turn uses it to create pictures of the
body
rf coils
Encircles the patient for the reception of larger areas
such as the hip, spine, and pelvis
● Body Coil
gradient coil is Too large for the resolution of smaller joints t or f
f, rf coil
Imaging protocols are selected by the MRI technologist or
radiologist prior to imaging
WORKSTATION
Directs the scanning process, converts data from
the RF coils and reconstructs the images
COMPUTER
computer converts data from __
rf coils
Direct of the scanning process, converts the data that is
received by the radiofrequency
coils and reconstructs it
computer
Greater ability to scan
claustrophobic/obese patients in MRI
open scanners
Reduction of scanning noise in what ype of mri scanner
open scanners
Ability to examine joints in WB conditions
to be able to detect protrusions,
herniations and spinal stenosis
upright scanners
Possibilities for performing tests or
procedures during scanning
open scanners
there is _ field strength, requiring adjustment of imaging sequences in open
scanner
lower
there is higer signal to noise ration in open scanners t or f
f, lower
○ Longer scanning times in open scanners t or f
t
Ability to examine patients too big to fit into the bore of the
magnet or must be scanned in the upright position for patients
with medical conditions such as
heart failure or seer thoracic kyphosis
UPRIGHT SCANNERS
Longer scanning times in both upright and open t orf
t
Possible image degradation in open t or f
f, iin upright
Placement of the patient in a painful
position which may increase movement which will
lead to decreased image quality in open t or f
f, in upright
As much as possible, you can move in MRI t or f
f, cannot move in MRI
Coronal Images are viewed from the _ (facing the patient)
front