Lecture 23 Flashcards
Computerized Tomography (CT) uses and time
Acute hemorrhage, bone abnormalities, fractures, calcified lesions, sinus disease. Used in emergency situations. 5 minutes
Computerized Tomography (CT) radiation
radiation is present
Magnetic Resonance Imaging (MRI) uses and time
Stroke, soft tissue disease, including tumors, multiple sclerosis, or inflammation. 30-120 minutes
Magnetic Resonance Imaging (MRI) radiation
no radiation
Diffusion Tensor Imaging (DTI) MRI uses and time
White matter tracts, surgical planning. 30 minutes
Diffusion Tensor Imaging (DTI) MRI radiation
no radiation
Positron Emission Tomography (PET) uses and time
Measure blood flow, glucose metabolism, and oxygen consumption. 30 minutes
Positron Emission Tomography (PET) radiation
radiation is present
Functional Magnetic Resonance Imaging (fMRI) uses and time
Detect neural activity by evaluating changes in blood flow. 60 minutes
Functional Magnetic Resonance Imaging (fMRI) radiation
no radiation
Contrast-enhanced CT
Used when trying to detect increased angiogenesis or breakdown of blood-brain barrier
Keys to CT
The #1 best study to evaluate a neurological patient in the emergency room (fast and available)
The study of choice for suspected bleed or trauma.
Best diagnostic tool for evaluating a patient with headache and/or neurologic deficit of unknown origin.
Best radiological tool for evaluation of hydrocephalus and shunt malfunction.
MRI T1
T1 images have increased contrast between gray and white matter compared to T2 images
MRI T2
Pathology is generally more evident on T2 scans compared to T1 scans
T2 images. what structures appear bright?
CSF, fat and edema
T1 images what structures appear bright?
Just fat, everything else is dark
Fluid-attenuated Inversion Recovery (FLAIR)
able to detect lesions in the lateral ventricles better with FLAIR
Contrast Magnetic Resonance Imaging
Use of a contrast agent with MRI highlights areas of breakdown of the blood-brain barrier or increased angiogenesis.
avoid during pregnancy
Able to detect tumors with contrast
T2 FLAIR with contrast
Gold standard for demyelination, infections, and axonal degeneration
DWI (diffusion weighted imaging)
Particularly useful when evaluating for ischemia
Also helpful in differentiating various lesions
DTI (diffusion tensor imaging)
Indicates shifts in water
Used to image pathways in the brain or fiber bundles in white matter
CTA (Computed tomography angiography)
is helpful in screening for carotid stenosis, aneurysm, and abnormal connections between arteries and veins
MRA (Magnetic resonance angiography)
very similar to CTA but can be performed with or without injection of contrast material.
Ventricles will be enlarged under certain conditions:
Hydrocephalus and brain atrophywill result in ventricular enlargement Hydrocephalus ex vacuo
Decrease in ventricles indicates mass effects
tumor and edema
Functional Magnetic Resonance Imaging
Measures neuronal activity by detecting changes in oxygenated blood flow
Measures gray matter activity
Main advantage over PET scan is no radiation
Positron Emission Tomography (PET)
The value of PET is the ability to measure the gamma rays as they travel through cerebral vasculature.
Tumor detection
