Advantages and Disadvantages of MRI

Advantages

• MRI possesses superior soft tissue imaging.
• Multi-planar image acquisition is possible. This means images can be acquired in any possible plan including sagittal, dorsal, axial, and oblique. Because no 2D reconstruction is required, there is no loss of information.
• The spatial resolution within an MRI image is superior to all other imaging modalities.
• There is no harmful ionizing radiation, which is paramount in humans and of no significance in animals. Because of this, the possibility of damaging effects (cancer induction, genetic defects, mutations) is null.

Disadvantages

• Cost. MRI is the most expensive commonly available imaging modality in veterinary medicine.
• Time. Performing an MRI study is time consuming. However, with stronger magnets becoming more readily available, the study times are declining and are no longer considered a significant limiting factor in most patients.
• Bone imaging is considered inferior to CT. This is true for cortical bone. MRI provides are great deal of information about the remainder of the tissues within the bone and is considered the modality of chose for certain disease processes. An example would be staging the extent of involvement of osteosarcoma within a patient considering a limb sparing procedure

When do I use MRI?

Appendicular Skeleton.
Especially when only soft tissue swelling is present, radiographically.

Joints.
Because of MRI’s superior soft tissue resolution, lesions involving soft tissues are clearly defined. MRI is an excellent modality for defining ligamentous and tendinous damage, partial vs. complete cranial crucial rupture, bone bruising (because of the accompanying subchondral edema and hemorrhage), and articular surface. MRI is sensitive for superficial soft tissue, musculature, capsular and synovial involvement, OCD lesion, and degenerative joint disease as well.

Axial Skeleton
Spinal Disease. MRI is the gold standard in human medicine. Excellent for identifying subtle changes, especially when radiographs are normal. Severe soft tissue changes can occur before bony changes, making this a more sensitive modality than CT. Allows for differentiation between acute and chronic disease processes.

Neurological disorders.
MRI is excellent for differentiating between congenital and acquired hydrocephalus and potentially identifying the cause. Anomalies such as Chiari malformation are easily identified.

Acquired lesions.
Including trauma related injuries (contusions, fractures, subacute and chronic hemorrhage, cerebral vascular accidents, spinal cord infarction, malacia and degenerative lesions.

Abdomen:
Portosystemic shunting. Standard protocols limited to the abdomen require less scan time than CT. Concurrent assessment of the brain for commonly accompanying alterations is possible. Intracranial changes may correlate with the shunt severity and influence surgical outcome.

Respiratory gated abdominal studies.
Same studies as mentioned for CT with superior soft tissue detail. Longer acquisition times are required.

Thorax:
Respiratory and cardiac gated thoracic studies. Relatively limited in veterinary medicine due to limited protocol design and scan time. Studies are useful in assessing mediastinal, pulmonary, pleural and heart base pathology. Cardiac studies are also possible.

CT and MRI Availability
AIC cross-sectional imaging schedule is flexible and serve commonly available Monday through Friday evening. Our studies are performed at human diagnostic imaging facility utilizing state of the art equipment, which yields better image quality and shorter scan times. Shorter acquisition times mean less time spent under general anesthesia and therefore, less risk to patient