| |
CT Scan |
MRI |
| Acronym for: |
Computed
(Axial) tomography |
Magnetic
Resonance Imaging |
| Application: |
Suited for
bone injuries,Lung and Chest imaging,cancer detection |
Suited for
ligament and tendon injury,spinal cord
injury,brain tumors |
| Scope of application: |
CT can
outline bone inside the body very accurately. |
MRI is more
versatile than the X-Ray and is used to examine a large variety of
medical conditions. |
| Principle: |
X-ray
attenuation was detected by detector & DAS system, follow by math. model
(back projection model) to calculate the value of pixelsm then become a
imag. |
Makes use of
the fact that body tissue contains lots of water (and hence protons)
which gets aligned to large magnetic field to produce net MDM vector.The
decay of MDM is detected as MR signal. |
| Ability to change the
imaging plane without moving the patient: |
With
capability of MDCT, after helical scan with Mlti-plane Reformation
function, an operator can constructe any plane. |
MRI machines
can produce images in any plane. |
| Principle used for
imaging: |
Uses X-rays
for imaging |
Uses large
external field,RF pulse and 3 different gradient fields |
| Cost: |
CT Scan
costs range from $1,200 to $3,200; they usually cost less than MRIs. |
MRI costs
range from $1200 to $4000 (with contrast); which is usually more than CT
scans and X-rays, and most examining methods. |
| Details of bony
structures: |
Provides
good details about bony structures |
Less
detailed compared to CT scan |
| Time taken for complete
scan: |
Usually
completed within 5 minutes |
Scanning typically run for about
30 minutes. |
| Details of soft tissues: |
Less tissue
contrast compared to MRI |
Much higher
detail in the soft tissues |
| Effects on the body: |
Despite
being small, CT can pose the risk of irradiation. |
No
biological hazards have been reported with the use of the MRI. |
| Radiation exposure: |
Moderate to high radiation |
None |
| Limitation for Scanning
patients: |
Patients
with any Metal implants can get CT scan |
Patients
with Cardiac Pacemakers are not allowed to get MRI scan done |
