Neuroimaging Techniques Quiz
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What was a significant advancement in CT technology compared to the first scanners?

  • Scanners have eliminated the need for patient movement.
  • Scanners no longer require any reconstruction of data.
  • Scanners can acquire data in seconds instead of hours. (correct)
  • Scanners can now operate without x-ray beams.

    • What differentiates T1 weighted images from T2 weighted images in MRI?

  • T1 images are more sensitive to acute hemorrhage than T2 images.
  • T1 images provide better contrast for anatomical details, while T2 images are better for pathology. (correct)
  • T1 images highlight water content, while T2 images highlight fat content.
  • T1 images are used exclusively for brain imaging, while T2 images are for other body parts.

    • How does the density of tissue affect x-ray absorption in CT imaging?

  • Tissue density has no impact on x-ray absorption.
  • Denser tissues absorb x-rays more than less dense tissues. (correct)
  • All tissues absorb x-rays at the same rate regardless of density.
  • Less dense tissues absorb x-rays more than denser tissues.

    • What is a feature of helical CT compared to traditional CT?

    <p>It combines continuous gantry rotation with table motion.</p> Signup and view all the answers

    What is a primary advantage of FLAIR imaging in detecting multiple sclerosis lesions?

    <p>FLAIR imaging suppresses the signal from cerebrospinal fluid, enhancing lesion detection.</p> Signup and view all the answers

    What is reconstructed mathematically in a CT scan to represent tissue density?

    <p>The differential absorption rates of x-rays.</p> Signup and view all the answers

    Which type of intracranial hemorrhage is typically characterized by blood accumulation between the skull and the outer layer of the dura mater?

    <p>Epidural hemorrhage</p> Signup and view all the answers

    What role does diffusion tensor imaging (DTI) play in neuroimaging?

    <p>DTI measures the integrity of white matter tracts.</p> Signup and view all the answers

    What determines the amount of x-ray absorption in CT imaging?

    <p>The density of the tissue traversed by the beam.</p> Signup and view all the answers

    Which of the following imaging techniques is specifically referred to as a method of interventional neuroradiology?

    <p>Catheter Angiography</p> Signup and view all the answers

    What is the primary component that MRI uses to generate images?

    <p>Hydrogen nuclei</p> Signup and view all the answers

    What does the magnetic field strength in MRI machines use as a measurement unit?

    <p>Tesla</p> Signup and view all the answers

    What occurs immediately after the radiofrequency wave is turned off in MRI?

    <p>Tissue emits a signal that is detected.</p> Signup and view all the answers

    Who completed the first whole body MRI construction in 1977?

    <p>Dr. Damadian with two post doc students</p> Signup and view all the answers

    What is a sequence in the context of MRI imaging?

    <p>A set of parameters for a specific type of image</p> Signup and view all the answers

    Which of the following planes can an MRI sequence be obtained?

    <p>Sagittal, axial, or coronal planes</p> Signup and view all the answers

    When was the first commercial MRI scanner installed?

    <p>1983</p> Signup and view all the answers

    What does the term 'homogenous magnetic field' refer to in MRI technology?

    <p>A consistent and uniform magnetic field</p> Signup and view all the answers

    Which MRI sequence specifically shows hyperintensity in water (CSF) for pathology evaluation?

    <p>T2W images</p> Signup and view all the answers

    What is a characteristic of T1W images regarding signal intensity?

    <p>Water (CSF) is hypointense</p> Signup and view all the answers

    What does the FLAIR sequence allow for in evaluation related to multiple sclerosis?

    <p>Enhanced visibility of white matter adjacent to ventricles</p> Signup and view all the answers

    In Diffusion Weighted Imaging (DWI), what is indicated by hyperintensity?

    <p>Acute ischemic infarcts</p> Signup and view all the answers

    What distinguishes T2W images from T1W images in terms of gray matter intensity?

    <p>Gray matter is isointense in both T1W and T2W images</p> Signup and view all the answers

    Which term describes the appearance of vessels and areas of blood-brain barrier breakdown when using Gadolinium-based contrast in MRI?

    <p>Hyperintensity</p> Signup and view all the answers

    What is a key distinction in T1W images compared to T2W images regarding edema?

    <p>Edema is hypointense in T1W</p> Signup and view all the answers

    What sequence is primarily used for detecting ischemic infarcts in MRI?

    <p>Diffusion Weighted Image</p> Signup and view all the answers

    What is the Hounsfield Unit value for water?

    <p>0</p> Signup and view all the answers

    Which of the following is NOT a characteristic of CT scans?

    <p>Sensitivity to small lesions</p> Signup and view all the answers

    Which term describes an imaging result that demonstrates an intermediate density similar to that of brain tissue?

    <p>Isodense</p> Signup and view all the answers

    What is the typical appearance of an epidural hematoma on a CT scan?

    <p>Biconvex shape</p> Signup and view all the answers

    Which condition would NOT typically require the use of intravenous contrast during imaging?

    <p>Acute intracranial hemorrhage</p> Signup and view all the answers

    What is the characteristic density of acute subdural hematoma on a CT scan within the first week?

    <p>High density</p> Signup and view all the answers

    Which type of imaging is considered more effective for detecting small lesions compared to CT?

    <p>MRI</p> Signup and view all the answers

    What imaging technique is typically used for assessing bone lesions?

    <p>CT</p> Signup and view all the answers

    Which type of hematoma is characterized by being lens-shaped and does not cross sutures?

    <p>Epidural hematoma</p> Signup and view all the answers

    What is the typical characteristic of late subacute blood products on a CT scan?

    <p>Isodense</p> Signup and view all the answers

    What is the common cause of acute cerebellar infarction?

    <p>Thromboembolic events</p> Signup and view all the answers

    What type of imaging is most effective for detecting intrinsic brain tumors?

    <p>MRI</p> Signup and view all the answers

    What is a significant disadvantage of MRI compared to other imaging modalities?

    <p>It can cause claustrophobia in some patients.</p> Signup and view all the answers

    For which of the following conditions is MRI considered the most effective imaging technique?

    <p>Intracranial tumor</p> Signup and view all the answers

    Which of the following tumors is classified as a benign extra-axial mass arising from the meninges?

    <p>Meningioma</p> Signup and view all the answers

    What imaging technique is primarily used to assess white matter tracts based on water diffusion characteristics?

    <p>Diffusion Tensor Imaging</p> Signup and view all the answers

    Which condition is characterized by a loss of myelin and associated with an autoimmune process?

    <p>Multiple sclerosis</p> Signup and view all the answers

    What imaging technique is specifically useful for imaging intracranial blood vessels?

    <p>MR Angiography</p> Signup and view all the answers

    In a Basilar Tip Aneurysm, which symptom is most commonly reported upon rupture?

    <p>The 'worst headache of life'</p> Signup and view all the answers

    What is the primary imaging modality used to assess Chiari I malformation?

    <p>MRI</p> Signup and view all the answers

    Which advanced MRI technique is utilized to evaluate brain metabolic activity?

    <p>Functional MRI</p> Signup and view all the answers

    Which condition is specifically noted for having a characteristic abnormal signal in the medial temporal and inferior frontal lobes on MRI?

    <p>Herpes encephalitis</p> Signup and view all the answers

    What is a primary use of Magnetic Resonance Spectroscopy (MRS)?

    <p>Measuring brain neurotransmitters</p> Signup and view all the answers

    Which MRI finding is associated with cytotoxic edema conforming to vascular territories?

    <p>Acute infarct</p> Signup and view all the answers

    Which feature of an Arteriovenous Malformation (AVM) is notable during imaging?

    <p>Arteriovenous shunting without intervening capillary bed</p> Signup and view all the answers

    What advantage does MRI have over CT imaging in evaluating posterior fossa structures?

    <p>Minimized artifact presence</p> Signup and view all the answers

    Study Notes

    Introduction to Neuroimaging

    • Neuroimaging is a presentation by Sandip Basak, M.D.
    • He is a Clinical Professor and Attending Neuroradiologist.
    • His email address is [email protected].

    Objectives

    • Describe computed tomography (CT) physics.
    • Distinguish CT densities of fluid, brain, calcification and fat.
    • Describe the use and indications for basic CT and MRI, emphasizing suspected acute hemorrhage.
    • Describe the appearance of blood in CT.
    • Identify different types of intracranial hemorrhage (subdural, epidural, subarachnoid).
    • Explain magnetic resonance imaging (MRI) physics.
    • Identify T1, T2, and FLAIR images.
    • Detail the benefits of FLAIR imaging for multiple sclerosis (MS) lesion detection.
    • Describe the role of diffusion-weighted images.
    • Discuss the advantages and disadvantages of CT and MRI.
    • Describe advanced MRI techniques (spectroscopy, diffusion tensor imaging (DTI), function MRI (fMRI)).
    • Define catheter angiography and interventional neuroradiology.

    Techniques in Neuroimaging

    • Plain Films
    • Ultrasound
    • Nuclear Medicine
    • CT
    • MRI
    • MR Angiography
    • Catheter Angiography
    • Interventional Neuroradiology

    Radiologic Convention for Right and Left

    • CT image views are consistent with a patient lying at the foot of the bed.
    • Right and left are reversed in the axial plane of the image.

    Computed Tomography

    • Developed by Godfrey Hounsfield and Allan Cormack between 1972 and 1973
    • Later awarded the Nobel Peace Prize.
    • First scanners took hours to acquire data for a single slice and days to reconstruct data, but now the entire brain can be imaged in seconds.
    • CT uses a highly collimated x-ray beam that rotates around the patient.
    • Detects differential absorption rates of the x-ray beam; different tissues absorb x-rays at varying rates.
    • Mathematically reconstructs density values based on locations the x-ray beams pass through in the body.
    • Patient lies on table that moves.
    • Thin x-ray beam passes through the patient with detectors located on opposite sides.
    • Image density depends on tissue density.
    • Many rows of detectors (e.g., 256) can be used.
    • Helical CT combines continuous gantry rotation with table motion to generate images more efficiently.

    CT

    • Different tissues attenuate the x-ray beam differently.
    • Density is expressed in Hounsfield Units (HU).
    • The scale for HU ranges from -1000 to +1000.
    • Different tissues, such as air, fat, water, brain, acute blood, and calcification, have different HU values.
    • Terminology related to density includes hyperdense, hypodense, and isodense.

    CT Advantages and Disadvantages

    • Advantages: Fast, less costly than MRI, very sensitive to hemorrhage, and produces high-quality images of calcium and bone.
    • Disadvantages: High radiation dose, not as sensitive to small lesions or certain anatomic structures compared to MRI, and metal artifacts can be significant.

    CT Most Effective Uses

    • Intracranial hemorrhage
    • Acute trauma (head, neck, body, and spine)
    • Stroke imaging
    • Fractures
    • Sinusitis
    • Bone lesions
    • Dental imaging
    • Myelography
    • CT angiography
    • CT perfusion
    • Temporal bone

    Sagittal Plane

    • Divides the body into right and left halves.
    • Other relevant planes for body imaging include coronal and horizontal planes.

    MRI

    • Developed by Raymond Damadian in 1970.
    • Discovers abnormal cells are different.
    • First whole body MRI scan completed in 1977.
    • First commercial MR scanner installed in 1983.

    MRI Imaging of Hydrogen Nuclei

    • Hydrogen is the simplest and most abundant element in the human body.
    • All current MRI techniques are based on receiving and processing signals from protons.
    • MRI utilizes a magnetic field, radiofrequency pulses, and a computer to create images.

    MRI T1 and T2 Weighting

    • T1 and T2 weighting depends on differences in hydrogen ions (protons) in fat and water.
    • MRI uses signal intensity instead of density.
    • Signal intensity is dependent on water and fat.

    MRI T1W and T2W Images

    • T1W images show anatomy and are used to determine anatomy.
    • Water (CSF) shows up hypointense.
    • Edema shows up as hypointense.
    • White matter (fat) shows up hyperintense.
    • Gray matter shows up isointense.
    • T2W images show pathology.
    • Water (CSF) shows up hyperintense.
    • Edema shows up as hyperintense.
    • White matter shows up hypointense.
    • Gray matter shows up isointense.

    FLAIR (Fluid Attenuation Inversion Recovery)

    • Similar to T2 weighting.
    • CSF shows up hypointense.
    • Allows for evaluation of white matter adjacent to ventricles, such as in multiple sclerosis.

    Diffusion Weighted Imaging (DWI)

    • Primary sequence for detecting ischemic infarcts (not hemorrhage infarcts).
    • Shows hyperintensity with acute or subacute infarcts (up to 14 days).
    • Abnormal signal is hyperintense.

    MRI Intravenous Contrast

    • Uses Gadolinium (a rare earth element) based agents.
    • Produces hyperintensity in vessels/areas of blood/brain barrier breakdown.

    MRI Advantages and Disadvantages

    • Advantages: Excellent delineation of anatomy, excellent for detecting small lesions, very sensitive to pathology (edema, certain forms of blood, small lesions), excellent for evaluating posterior fossa structures, no radiation, and in utero imaging.
    • Disadvantages: Can be a long exam (routine noncontrast brain scan = 15 minutes), claustrophobia can be an issue, pacemaker contraindication and metallic foreign bodies relative contraindication, and expensive.

    MRI Most Effective Uses

    • Intracranial tumor, TIA/stroke, infection, demyelination, Epilepsy, Dementia, Hearing loss, Pituitary gland, Cranial nerve abnormalities, Pediatrics, metabolic disease, developmental delay, congenital anomalies, fetal brain and spine, trauma of brain or spine, spine degenerative change, cord abnormality, spine lesions, spine tumors, evaluation of arteries or veins in brain or spine, head and neck tumors, and infections.

    Specific Findings, Conditions, and Treatments in Neuroimaging

    • The slides reference many entities in neuroimaging, including, but not limited to, Chiari I Malformation, AVM, Parieto-Occipital AVM, Basilar Tip Aneurysm, Intracranial Lymphoma, Herpes Encephalitis, Meningioma, Acute Infarct, and Multiple Sclerosis.
    • Specific treatments are also mentioned, such as embolization, coiling, and angioplasty.
    • The details for each are in the notes.

    Advanced Techniques in MRI

    • Magnetic Resonance Spectroscopy (MRS): Measures brain neurotransmitters and biochemicals.
    • Diffusion Tensor Imaging (DTI): Evaluates white matter tracts based on water diffusion.
    • Functional MRI (fMRI): Measures brain metabolic activity (an indirect measure of neural discharge).

    Catheter Angiography

    • Invasive procedure uses catheter insertion via femoral artery; fluoroscopy locates the catheter in the Aorta, then contrast material is injected to visualize blood vessels.
    • It is considered the gold standard for imaging blood vessels.

    Interventional Neuroradiology

    • Minimally invasive treatments for brain, head, neck and spine conditions. Includes micro-catheter, micro-guidewire, balloon catheters, embolic materials, detachable coils, detachable balloons and stents (to mention a few of the techniques and instruments).

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    Description

    Test your knowledge on the advancements and principles of neuroimaging technologies such as CT and MRI. Explore key concepts including tissue density, imaging techniques, and specific advantages used in neuroimaging applications like multiple sclerosis detection. Challenge yourself with questions about how these technologies are utilized in clinical environments.

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