Jeff Binder R.T. (R)

STRENGTHS WEAKNESSES Readily available Low cost Well known uses Best line pair

performance

False negatives (fx) Ionizing radiation Poor resolution Poor soft tissue

visualization Poor spacial localization C1/c2, c6/c7 hard to

visualize

Attenuating technology

Rule out advanced imaging Introductory study Evaluates IVF well Not good for central canal stenosis

Xray images taken in “sections” (slices)

Blurs areas that are not of interest Similar strengths and weaknesses as

plain film Attenuating technology

Xray images taken of spinal cord after radiopaque contrast is injected

When used with CT it is the best tool to visualize central canal stenosis

Dr. looks for displacement of contrast on xray

Attenuating technology

Headache (most common) Infections Arterial bleeding Arachnoiditis

First contrast used was air

Technetium 99 radio isotope used Emission technology (from the patient) “hot spots” on scan are osteoblastic

activitySPECT: Single Photon Emission

Computerized TomographyPhosphate used as carrier molecule

PET: Positron Emission TomographyGlucose used as carrier molecule

Attenuating technology Computer generated pictures Hounsfield Units Pixels and voxels Volume averaging used Slice thickness scout films used

STRENGTHS WEAKNESSES

Widely available Improved soft tissue

visualization 3d imaging Accurately measure a

variety of structures Image manipulation

possible (bone and soft tissue windowing)

May be combined with myelogram for canal stenosis exam

Ionizing radiation Higher cost Intracranial artifacts Artifacts secondary to

metallic implants Radiation dose

Sound waves used to form images No radiation Readily accessible Lower cost Interact with patient

Emission technology (from the patient)

Hydrogen molecules used for emission

Cortex of bone=black • Due to lack of hydrogen (water molecules)

Evaluates Physiology

Spinal fracture Soft tissue injury Skeletal survey for metastasis Post traumatic complications Peripheral entrapment Central canal stenosis Intracranial abnormalities Vascular imaging (MRA first choice)

Magnet (field) strength depicts image quality• 1.5 tesla magnetic minimum• Larger the magnet= better image quality

RF coils are placed on or near the patient to excite the tissue

Larmor equation• Frequency of procession= gyro magnetic ratio x strength

of field

White= high signal, Many H+ emitting signal

Black= low signal, No H+ emitting signal

Tr= Repetition timeTe= echo time

Cortex=black CSF=black Fat=white Tr= 200-600ms Te= 25ms

Cortex=black CSF=white Tr= ~1500+ ms Te= 50+ ms

BOLD: Blood Oxygen Level Dependant

Physiology presented• Cortical activation• Retinotopic organization of the visual cortex• Cerebral basis for language• Mapping of the motor cortex• Memory• Studying psychiatric disorders

Advantages over PET• No ionizing radiation, less expensive, widely available, studies

can be frequently repeated

Fake functional Computer tricks to make a study look

like a motion study. Really a series of static images