Physician’s Guide

Practitioners are often faced with selecting the correct modality, most often the decision is between MRI and CT Scan.  Some of the factors that can determine this are: area of complaint, presenting symptoms, and suspected pathology.  We have put together a list to help as a reference in case there is a question to which modality would be best to order.

Area of Complaint Presenting Symptoms Suspected Pathology Imaging Modalities Indicated

Head Dizziness Acoustic neuroma, multiple sclerosis, temporal lobe lesion, tumor, or stroke, sub or epidural hematoma, cyst
MRI: The most sensitive for suspected pathology listed
CT: Less expensive than MRI but not as sensitive
Head Seizures Temporal lobe lesion, tumor, or stroke, multiple sclerosis, cerebrovascular accident, cyst MRI: The most sensitive for suspected pathology listed
CT: Less expensive than MRI but not as sensitive.
Exception: CT is more sensitive in acute stage (1st 3 days) post cerebral hemorrhage.
Head Localized pain or headaches Tumor, abscess, arteriovenous malformation, trauma, cyst MRI: Most Sensitive
CT: Less expensive and less sensitive.
Exception: CT is more specific for calcified tumors.
Head Non-localized headache Tumor or other space occupying lesion, mastoiditis sinusitis, hydrocephalus, cyst. MRI: Most Sensitive
CT: Less expensive and less sensitive.
Head Behavioral changes Tumor or other space occupying lesion, Cerebrovascular Accident (CVA), cyst or multiple sclerosis. MRI: The most sensitive for Tumor or Multiple Sclerosis.
CT: Less sensitive for hemorrhage in acute stage 2st 3 days post hemorrhage.
Head Post Trauma or surgery Subdural or Epidural Hemmatoma, or other Hemorrhage, Infection, Abscess. MRI: Most sensitive for Hemorrhage in Subacute Stage (4 to 10 days post trauma) or Chronic Stage (10 days or more post trauma), for infection or abscess.
CT: Most sensitive for hemorrhage in Acute Stage 1st 3 days post trauma.
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Head Sensory changes Acoustic Neuroma, Occipital Lobe Lesion, Optic Chiasm or Optic Nerve Lesion, Meningioma, Cyst, Olefactory Nerve Lesion.
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MRI: Most Sensitive
CT: Less expensive and less sensitive.
Exception: CT is more specific for calcifying lesions.
Head History of Cancer Metastasis MRI: Most Sensitive
CT: Less sensitive except for calcifying lesions.
Head Amenorrhea or Lactation Prolactinoma, or other Pituitary Tumor MRI: Most Sensitive
CT: Less sensitive due to scatter artifact from Sella Turcica.
Cervical Unilateral or Bilateral symptomology of neck or upper extremities. Arthritic Hypertrophy, Herniated Nucleus Pulposus (HNP), bulging Anulus Fibrosus, Cord Tumor, Syringomylia, Stenosis of Spinal Canal of Foraminal Openings, Non-displaced Fracture, Multiple Sclerosis (MS) MRI: Most sensitive for various soft tissue structures-discs, canal contents, tumors or MS.
CT: More sensitive for bony structures or for non-displaced fracture.
Cervical History post trauma or surgery. HNP, Recurrent HNP versus scar tissue, Ligamentous Tearing, Non-displaced Fracture, Syringomylia, Infection, Recurrent Cord Tumor. MRI: Most sensitive for Syringomyelia, HNP, or Post Surgery Evaluation.
CT: More sensitive for non-displaced fracture.
Video Flouroscopy: Most sensitive for joint motion abnormalities post trauma.
Cervical Loss of range of motion or excessive motion of individual motor units. Ligamentous Tearing or Laxity, Muscle Spasm. MRI: Most sensitive for soft tissue structures and inflammatory reactions.
CT: Most sensitive for bone pathology.
Video Flouroscopy: Most sensitive for joint motion abnormalities related to ligamentous injury.
Cervical History of Cancer or Systemic Disease affecting bone (Pagets, Lupus, etc.) Metastasis to Spinal Cord, or bony structures, marrow changes secondary to systemic disease, pathological fracture from metastasis. MRI: The most sensitive for evaluation of Metastasis or marrow changes a known area.
CT: Sensitive for bony detail.
Nuclear Medicine: Offers whole body coverage for initial localization of metastasis to bone, best for initial screening.
Thoracic Unilateral or Bilateral Symptomology of trunk or lower extremities Arthritic Hypertrophy, HNP, Bulging Anulus, Cord Tumor, Syringomyelia, Stenosis of Canal or Foraminal Openings, Compression Fracture. MRI: Most sensitive for various soft tissue structures-discs, canal contents, tumors, syringomyelia.
CT: More sensitive for bony structures.
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Thoracic History Post Trauma or Surgery. Compression Fracture, Syringmyelia, Recurrent HNP versus Scar Tissue, Recurrent Cord Tumor, Infection. MRI: Most sensitive for various soft tissue structures.
CT: Best for Bony Details.
Thoracic History post cancer or Systemic Disease affecting bone (Pagets, Lupus, etc.) Metastasis to Spinal Cord or Bony Structures, Marrow changes secondary to systemic disease, pathological fracture. MRI:Most sensitive for evaluating soft tissue structures and marrow.
CT: Best for Bony Details.
Nuclear Medicine: Offers whole body coverage for initial localization of metastasis disease in bone.
Lumbar Unilateral or Bilateral Symptomology of lower back, pelvis, lower extremities, or incontinence. Arthritic Hypertrophy, HNP, Bulging Anulus, Conus or Cauda Equina Tumor, Stenosis of Canal or foraminal openings, Compression Fracture, Abdominal Aortic Aneurysm, Tethered Cord. MRI:The most sensitive for soft tissue structures, easily identifies aneurysms.
CT: Best for bony details (bulging anulus versus osteopathic growth) also visualizes aneurysms well.
Lumbar Compression Fracture, Neural Canal or Foraminal Stenosis, Infection, Recurrent HNP versus scar tissue, recurrent conus or cauda equina tumor. Compression Fracture, Neural Canal or Foraminal Stenosis, Infection, Recurrent HNP versus scar tissue, recurrent conus or cauda equina tumor. MRI:The most sensitive for soft tissue evaluation post surgery or trauma.
CT: Best for bony detail.
Lumbar History of cancer or systemic disease affecting bone (Pagets, Lupus, etc.) Metastasis to Spinal Cord or Bony Structures, Pathological fracture, marrow changes secondary to systemic disease. MRI:Most sensitive for evaluating soft tissue structures, best for follow-up evaluation of known mets or marrow abnormalities.
CT: Best for bony detail.
Nuclear Medicine: Offers whole body coverage, best for initial screening.
Shoulder Chronic Dislocation Glenoid Labrum Tear, Degenerative Joint Disease. MRI: Most accurately depicts glenoid labrum glenoid fossa.
Shoulder Pain and Weakness, Decreased range of motion, history of arthritis or trauma. Full or partial thickness rotator cuff tear, impingement syndrome, fracture, synovial cysts, neoplasm, effusion, injection. MRI:Most sensitive for partial thickness tears, same sensitivity as arthrography for full thickness tears, most sensitive for synovial cysts, impingement syndrome, neoplasm, effucion, infection
Arthrography: equal sensitivity with MRI for full thickness tears, less sensitive for partial thickness tears.
Hip History of cancer or systemic disease affecting bone (Pagets, Lupus, etc.) Metastatic tumor, occult fracture, marrow changes to secondary systemic disease. MRI:Highly sensitive to metastatic lesions and marrow changes, can evaluate fractures in multiple planes.
CT:More sensitive for bony detail.
Nuclear Medicine:Offers whole body coverage best for initial localization of metastatis disease in bone.
Hip Unilateral or Bilateral pain, decreased range of motion,
history of trauma or surgery.
Avascular necrosis, tummor, degenerative joint disease, occult fracture. MRI:The most sensitive imaging modality for detecting in schemic necrosis in bone, only modality that images hyaline cartilage.
NOTE: Hip prosthesis patients are safe to scan by MRI degradation of images may or may not occur depending on content of prosthesis.
CT:Good bony detail, sensitive for occult fractures.
Wrist, Elbow, Ankle, and Foot Pain, decreased range of motion, history of trauma or prior surgery, history of arthritis. Vascular necrosis, intra-articular loose bodies, transchondral fracture, cyst formation, tendon or ligament tearing, soft tissue or bony tumor, fracture non-unions. MRI:The most sensitive for soft tissue evaluation and chronic fractures, multiplanar evaluation advantages.
XRAY: Best for bony detail and morphology.
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Chest: Lungs and Heart History of cancer or Hodgkin’s disease.. Metastasis, Lymphatic Involvement. MRI:Less sensitive than CT, but good for followup if CT is equivocal, images substernal lymphadenopathy well – no scatter artifact.
CT: Equivalent to or more sensitive than MRI, less affected by peristaltic, respiratory and pulsatile motion, best for initial screen.
Ultrasound: Offers high resolution imaging of lesions, good initial screen if small lesions are suspected.
Abdomen: Liver, Spleen, Pancreas, and Kidneys History of cancer, loss of function, chronic or acute, localized or non-localized abdominal pain. Primary or Metastatic, Tumor Involvement, benign cyst, hemochromatosis, infection. MRI: Equivalent to or less sensitive than CT, good for follow-up when CT is equivocal, best for hemochromatosis.
CT: Equivalent to or more sensitive than MRI, less affected by peristaltic, respiratory pulsatile motion, best for initial screen.
Ultrasound: Offers very high resolution imaging of lesions, good initial screen if small lesions are suspected.
Pelvis: Bladder, Uterus, Ovaries, Prostate History of benign masses or cancer, chronic or acute localized or non-localized pelvic pain. Primary or metastatic, tumor involvement, benign tumor or cyst, infection. MRI: Best at evaluating wall invasion by Tumor growth best for follow-up after tumor sites have been localized with CT.
CT: Good for initial screening and localization of gross tumors..
Ultrasound: Best for initial screening of pelvic lesions, real time imaging offers best structure identification, very high resolution capabilities.