MRI is the modality of choice for identifying and characterizing abnormalities in soft tissue and bone that are not detectable using other imaging modalities.

MRI has the advantage of being able to accurately identify and characterize abnormalities in soft tissue and bone that are not detectable using other imaging modalities such as ultrasound, CT, or myelography. As a result, MRI is often the modality of choice for the diagnosis of patients with unexplained symptoms such as:

• Seizures
• Neck or back pain
• Abnormal nasal discharge
• Soft tissue masses
• Vestibular symptoms
• Paresis
• Lameness
• Ataxia
• Behavioral changes

Specific indications for MRI include:

Pelvic

• Anal gland adenocarcinoma
• Bladder carcinoma
• Soft tissue carcinoma
• Primary bone tumor
• Prostate carcinoma
• Uterine neoplasma
• Osteosarcoma

Vascular

• Intracranial aneurysm
• Intracranial arteriovenous malformation
• Evaluation of thrombosis, including aortic, caval, and portal vein

Spine and spinal cord

• Disk pathology 
  • Annular tear
  • Dehydration
  • Definitive classification of herniation (annular vs. central,
    contained vs. non-contained, free fragment)
• Intervertebral disk disease
• Diseases of the spinal cord
• Spinal cord trauma
• Spinal cord tumor
• Stenosis: lumbar, cervical, neck
• C1-C2 subluxation and basilar invagination
• Congenital abnormalities
• Discospondylitis
• Post-op recurrence of intervertebral disk disease
• Epidural hematoma
• Hydromyelia/syringomyelia
• Metastases
• Neoplasm
• Thoracic spine
• Trauma, fracture/dislocations of cervical or thoracic spine with cord compression and hemorrhage
• Myelitis

**Note: MR myelogram sequences are typically added to spine studies**

Head & neck

• Seizures
• Brain tumor
• Visual/hearing loss, brain lesions
• Progressive neurological deficit
• Cranial neuropathies/hydrocephalus
• Optic nerve lesions
• Pituitary macroadenoma
• Meningioma
• Nasal masses
• Neck masses
• Oral masses 
• Suspected vascular event
• Trauma prognosis, shearing injuries
• Vascular malformations
• Thyroid masses
• Salivary masses
• Suspect or rule out foreign body

Musculoskeletal/orthopedic

• Stifle/elbow, meniscus tears, ligament tears, chondral and osteochondral defects, patellar tendon tears
• Occult osseous injury, bone contusion/occult stress fracture 
• Primary bone tumors 
• Avascular necrosis: hip, shoulder, wrist, foot, bone marrow
• Metastatic disease
• Neoplasm detection/staging
• Osteomyelitis
• Shoulder, ganglion cyst, rotator cuff tendinosis/tendinitis, rotator cuff tear
• Lymphoma and multiple myeloma

Chest

• Thoracic mediastinal masses
• Soft tissue abnormalities
• Metastases screening 
• Primary or metastatic lung carcinoma
• Cardiac masses
• Congenital heart disease

Abdomen

• Liver, hemangiomastic, metastases, thrombosis or hepatic vein, portal vein
• Renal masses 
• Splenic masses
• Hepatic masses
• Pancreatic masses/tumor
• Portosystemic shunts 
• PVC—thrombosis or tumor
• Adrenal masses