Why choose MRI or CT?

Often a patient is sent for cross-sectional imaging for evaluation of a particular body part. This usually facilitates the choice of CT or MRI, as there are some clearly defined differences between the modalities when considering specific anatomic regions.

Region
Abdomen
MRI
	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*
	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI
	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*
	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI
	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*
	CT recommended for osseous disease only.
General skeleton
MRI
	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*
	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI
	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*
	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI
	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*
	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain disease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI
	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*
	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI
	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*
	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI
	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*
	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI
	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*
	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI
	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*
	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI
	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*
	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI
	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*
	CT recommended for osseous disease only.
General skeleton
MRI
	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*
	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI
	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*
	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI
	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*
	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain disease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI
	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*
	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI
	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*
	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI
	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*
	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI
	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*
	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI
	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*
	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI
	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*
	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI
	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*
	CT recommended for osseous disease only.
General skeleton
MRI
	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*
	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI
	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*
	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI
	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*
	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain disease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI
	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*
	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI
	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*
	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI
	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*
	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI
	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*
	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI
	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*
	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI
	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*
	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI
	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*
	CT recommended for osseous disease only.
General skeleton
MRI
	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*
	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI
	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*
	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI
	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*
	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain disease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI
	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*
	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI
	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*
	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI
	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*
	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI
	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*
	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI
	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*
	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI
	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*
	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI
	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*
	CT recommended for osseous disease only.
General skeleton
MRI
	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*
	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI
	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*
	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI
	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*
	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain disease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI
	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*
	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI
	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*
	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI
	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*
	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI
	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*
	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI
	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*
	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI
	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*
	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI
	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*
	CT recommended for osseous disease only.
General skeleton
MRI
	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*
	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI
	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*
	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI
	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*
	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain disease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI
	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*
	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI
	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*
	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI
	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*
	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI
	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*
	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI
	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*
	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI
	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*
	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI
	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*
	CT recommended for osseous disease only.
General skeleton
MRI
	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*
	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI
	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*
	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI
	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*
	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain disease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI
	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*
	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI
	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*
	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI
	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*
	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI
	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*
	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*	CT recommended for osseous disease only.
General skeleton
MRI	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain disease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI
	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*
	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI
	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*
	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI
	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*
	CT recommended for osseous disease only.
General skeleton
MRI
	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*
	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI
	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*
	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI
	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*
	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain dis-ease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI
	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*
	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI
	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*
	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI
	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*
	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI
	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*
	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI
	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*
	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI
	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*
	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI
	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*
	CT recommended for osseous disease only.
General skeleton
MRI
	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*
	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI
	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*
	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI
	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*
	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain dis-ease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI
	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*
	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI
	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*
	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI
	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*
	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI
	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*
	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI
	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*
	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI
	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*
	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI
	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*
	CT recommended for osseous disease only.
General skeleton
MRI
	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*
	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI
	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*
	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI
	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*
	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain dis-ease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI
	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*
	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI
	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*
	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI
	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*
	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI
	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*
	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*	CT recommended for osseous disease only.
General skeleton
MRI	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain dis-ease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI
	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*
	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI
	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*
	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI
	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*
	CT recommended for osseous disease only.
General skeleton
MRI
	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*
	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI
	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*
	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI
	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*
	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain dis-ease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI
	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*
	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI
	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*
	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI
	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*
	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI
	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*
	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*	CT recommended for osseous disease only.
General skeleton
MRI	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain dis-ease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region
Abdomen
MRI	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.
CT*	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock
MRI	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.
CT*	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle
MRI	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.
CT*	CT recommended for osseous disease only.
General skeleton
MRI	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).
CT*	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants
MRI	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.
CT*	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)
MRI	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).
CT*	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain dis-ease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses
MRI	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.
CT*	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears
MRI	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.
CT*	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax
MRI	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.
CT*	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region
MRI	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.
CT*	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

Region	MRI	CT*
Abdomen	MRI can be used, but requires special sequences and expertise.  In the future MR may be used more for the characterisation of abdominal masses and nodules in veterinary patients.	CT is the current modality of choice providing good quality images and being much easier and faster to perform.
Elbow and Hock	MRI can provide additional information concerning soft tissue, bone oedema, tendon and cartilage pathology.	CT is usually recommended. Complimentary to arthroscopy in elbow disease.
Shoulder and Stifle	MRI preferred modality - great potential for assessment of muscular, tendinous, ligamentous and meniscal injury.	CT recommended for osseous disease only.
General skeleton	MRI advantageous in neoplastic disease (such as bone tumours, infection etc.).	CT useful for angular limb deformities and fracture repair planning.
Patients with metallic implants	In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differ depending on the MR sequence used.  Where Tungsten implants are used MRI can still provide useful information in the right circumstances.	The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.
Central nervous system (CNS)	Imaging modality of choice for CNS. Specific additional MRI sequences can be very useful – these include radient echo sequences (haemorrhage), diffusion weighted imaging (ischaemic disease), FLAIR sequences (perilesional oedema and identification of pure fluid) and STIR sequences (to evaluate muscle, bone and nerve root changes).	CT myelography is necessary to identify significant sites of spinal cord compression. Intramedullary lesions are better recognized on MRI without the inherent risks of myelography. Use CT alone to diagnose brain dis-ease ONLY if MRI is not available. Not generally suitable for assessment of foramen magnum herniation.
Nasal cavities and sinuses	MRI is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis and contrast enhancing lesions.  Unlike other imaging modalities MRI can also detect early infiltration/infection in the brain.	CT is extremely useful in assessment of the nasal cavities and frontal sinuses. Effective in the assessment of turbinate, maxillary and palatine destruction, mass lesions, presence of fluid, osteomyelitis, and contrast enhancing lesions. CT can be used for guided FNA’s or biopsies.
External, middle and inner ears	MRI can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy. MRI allows assessment of cranial nerves VII and VIII, the cochlea and semicircular canals and the adjacent brainstem.	CT can detect the fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy.
Thorax	MRI can be used for thoracic imaging in some situations. Useful for mediastinal masses, thoracic wall masses and pleural space disease.	CT is the modality of choice. Superior metastatic screening when compared to radiographs.
Pelvic region	MRI is ideal for the evaluation of the pelvic organs and surrounding regions.	CT evaluation of the pelvic region provides good quality images, being much easier and faster to perform.

*In general, contrast is advised for most CT examinations with the exception of cases where its administration could compromise the health of the patient, or in cases where bone imaging alone is required.

If you would like to discuss a case before imaging, for advice on modality selection, please do not hesitate to contact BURGESS DIAGNOSTICS. Email enquiries@burgessdiagnostics.com giving full contact details and brief details of the case, and we will endeavour to answer your queries.