Anatomic Imaging Flashcards
What is XR radiography primarily used to evaluate?
Trauma (fx)
Degenerative disease (RA)
Post-op checks
What is the difference between fluoroscopy and XR?
Fluoroscopy is real-time XR, continuous radiation passing through the body onto a fluorescent screen to produce a moving XR image
Fluoroscopy used for both diagnosis and intervention
What are the main imaging modalities that use fluoroscopy?
Swallow studies
Angiography
Myelography
Why have barium swallow studies largely been replaced by endoscopy?
Time consuming
Contrast
Radiation
What invasive procedure involves inserting a catheter into a large blood vessel and is guided to a target blood vessel?
Angiography
What type of fluoroscopy injects contrast intrathecally?
Myelography
What is a myelography used for?
Inject contrast to visualize on CT:
Spinal stenosis, nerve root compression, CSF leak, and if an MRI in a pt is contraindicated (they have metal devices)
What are the pros of using myelography?
Defines subarachnoid space
Identifies spinal block
What are the cons to using myelography?
Invasive
Can cause HA and CSF leak
Why would ultrasound be used to evaluate carotid stenosis?
US can quantitate blood velocity
What imaging modality measures in radiodensity?
Computed Tomography (CT)
What imaging modality measures in radiointensity?
Magnetic Resonance Imaging (MRI)
What is a narrower window of Hounsfield units comparing?
Areas with similar HUs (Soft tissue vs blood)
What is a wide window of HUs comparing?
Areas with very different HUs (Bone vs air)
What is the level of the CT? What is the window?
Level: Center of the window
Window: Range of units
What imaging modality is the most beneficial for ruling out a large neurological pathology?
Computed Tomography
What imaging modality has low sensitivity in the posterior cranial fossa?
CT
What is the preferred initial study for patients with acute (within 3 hours) neurological symptom onset?
Non-Contrast CT
When is a contrast-enhanced CT typically indicated?
Neurological symptoms lasting longer than 3 hours
Neoplasm
Infection
Vascular disease
Inflammatory disease
When is a contrast-enhanced CT typically not indicated?
Trauma
Rule out hemorrhage
Hydrocephalus
Dementia
Epilepsy
What type of contrast is used for CT? MRI?
CT - Iodine
MRI - Gadolinium
What is the risk of using gadolinium-based contrast?
Nephrogenic systemic fibrosis in patients with renal insufficiency
What does radiographic enhancement mean?
Tissue gets brighter when contrast is applied, reflects vascularity of tissue
What neurological structures will enhance normally with IV contrast?
Cerebral blood vessels
Meninges
Pineal gland
Pituitary gland
Choroid plexus
What does enhancement in the brain parenchyma indicate?
Blood brain barrier is absent or dysfunctional
What is the difference between XR and CT Angiography?
XR - Can only visualize vessels where catheter is, higher resolution
CT - can evaluate vessels from origin to intracranial, lower resolution
What imaging modality is best for evaluating ischemia?
MRI - Can see ischemic tissue whereas CT contrast will not show contrast going to ischemic area
How do CSF and white matter appear in a T2 MRI?
CSF - Bright, hyperintense
White matter - Dark, hypointense
What is the difference between a normal T2 MRI and a T2 FLuid Attenuated Inversion Recovery?
FLAIR removes CSF from T2 image and can locate areas of abnormal fluid collection/fluid with increased ptn content (edema, abscess)
