jeff binder r.t. (r). strengthsweaknesses readily available low cost well known uses best line...
TRANSCRIPT
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