RADIOLOGY A

Lateral view, Medial view, Basal view

What are the different views used to see the brain surfaces?

. Lateral, Third, Fourth

What are the major ventricles listed?

. Foramen of Monro, Aqueduct of Sylvius

What are the ventricular conduits?

. Foramina of Luschka (lateral apertures), Foramen of Magendie (median aperture)

What are the apertures of the fourth ventricle?

. Ventricles seen in the midline

What does a normal brain CT scan show regarding the ventricles?

. Something is compressing the brain from either side

What does a midline shift signify?

. Shift of septum pellucidum, computed in millimeters

How is a midline shift measured?

. 5mm

What amount of midline shift is considered significant and signifies a surgical indication?

. Sulci and Gyri are well-defined

What does a normal brain show regarding Sulci and Gyri?

. Skull X-Ray

Which imaging modality is described as "very basic"?

. Anteroposterior (AP) view, Lateral view, Open-mouth view, Towne's view

What are the different views for a skull x-ray?

. Visualizes the odontoid process of the spine (C1 & C2)

What does the Open-mouth view for skull x-ray visualize?

. Visualizes the sinuses by tilting the head

What does the Towne's view for skull x-ray visualize?

. Many structures are overlapping which leads to compromised details

What is the main difficulty with using skull x-rays?

. Not usually ordered nowadays because of its limited value

What is the current status of skull x-rays being ordered?

. Posterity (e.g., when a patient has a knife stuck in his head)

For what purpose are skull x-rays sometimes used nowadays?

. Rarely ordered

Are skull x-rays usually ordered in cases of head trauma?

. CT Scan

Which imaging modality is ordered more than skull x-rays?

. Gives more detail as it visualizes more structures of the brain and how foreign bodies go deep into the brain

What advantage does a CT Scan have over skull x-rays?

. Acquire a detailed patient history then use the NEXUS criteria or Canadian CT Scan rule

In the ER for head injury, what is done before deciding to do a CT scan?

. If results show any type of intracranial pathology

Based on the NEXUS criteria or Canadian CT Scan rule, when is a CT scan performed?

. A black and white picture of the brain with more detail than skull x-rays

How is a CT scan pictured and described?

. Density

What is the language of CT scans, in comparison to the normal brain?

. Hyperdense, isodense, hypodense

What terms are used to describe density in CT scans?

. Cuts (e.g., axial cut)

How are CT scans described?

. Good for defining the bony anatomy

What is a strength of CT scan?

. Not as good as MRI for soft tissues

What is a limitation of CT scan compared to MRI?

. Good if fast results are needed like in emergencies

When is a CT scan particularly useful?

. Around 1 to 5 minutes

How long does a non-contrast cranial CT typically take?

. 45 minutes to an hour (or longer sometimes depending on the number of sequences)

How long does an MRI typically take?

. Radiation

What is the basis of CT scans?

. 100 to 150 skull x-rays

How many skull x-rays is 1 CT scan equivalent to in terms of radiation?

. Intensity

What is the language of MRI, in comparison to the normal brain?

. Hyperintense, isointense, hypointense

What terms are used to describe intensity in MRI?

. Sequences

How are MRI scans described?

. A colored picture of the brain with more detail than CT scans

How is an MRI pictured and described?

. Visualizes the soft tissues, cranial nerves, blood vessels, scalp, nasal cavity, orbital area, etc

What structures does MRI visualize well?

. Magnetism

What is the basis of MRI?

. Not using radiation

What is an advantage of MRI over CT scan?

. Magnetic strength

What is the quality of MRI based on?

. The higher the magnetic strength, the better the detail

How does magnetic strength relate to MRI detail?

. Tesla units

What units are used for magnetic strength in MRI?

. 1.5 Tesla

What magnetic strength is sufficient for basic, diagnostic cranial imaging?

. 7 Tesla

What magnetic strength is used for research purposes tracing cerebral architecture and redefined fibers?

. Cerebral Angiography

What type of imaging focuses on blood vessels?

. Visualizes the entire cerebral network of the brain

What can cerebral angiography visualize?

. Injections

How does cerebral angiography concentrate on certain areas?

. CT scan or MRI

How can angiography be done?

. Magnetic fields and RF (radio frequency) pulses

What is the energy source for MRI Angiography?

. Ionizing X-rays

What is the energy source for CTA Angiography?

. Hydrogen atoms in blood

What is the signal origin for MRI Angiography?

. Contrast attenuation of X-rays

What is the signal origin for CTA Angiography?

. Gadolinium (optional)

What contrast agent is used for MRI Angiography?

. Iodinated contrast (required)

What contrast agent is used for CTA Angiography?

. Sensitive to blood flow

What is MRI Angiography sensitive to?

. Captures vascular anatomy with contrast

What does CTA Angiography capture?

. Functional blood flow, soft tissues

What is MRI Angiography best for?

. Structural vessel detail, calcification

What is CTA Angiography best for?

. Cerebral Catheter Angiography (CCA)

What is considered the gold standard for angiography?

. Provides well defined images of small structures

Why is CCA useful?

. Aneurysm

What is the most common indication for the use of CCA?

. High-resolution, three-dimensional, pathoanatomical data about the cerebral vasculature and also allows real-time analysis of blood flow

What kind of data does cerebral angiography (specifically referring to CCA based on context) provide?

. Similar to X-ray but with direct injection into the actual blood vessel and may be manipulated to view structures in three dimensions (3D)

How is CCA similar to and different from X-ray?

. From the vessels of the thigh or radial artery

Where is the catheter inserted during a CCA procedure?

. Thigh

Which insertion site is preferred for CCA, thigh or neck?

. Less painful and more accessible

Why is the thigh preferred for CCA insertion?

. It is done with the patient either sedated or on local anesthesia

What is a disadvantage of CCA?

. Diagnosis and treatment

For what purposes is CCA used?

. Coiling

What procedure may be done during CCA to obliterate an aneurysm?

. Detection of arteriovenous malformation

What else is CCA good for detecting?

. Diffusion Tensor Imaging (DTI)

What is a recent advancement in MRI that examines the structure of nerve cells and intricate neural networks?

. Brownian motion of water molecules

What does DTI use to generate detailed data for imaging?

. An MRI type of imaging

What type of imaging is Tractography?

. Maps neural pathways based on data obtained from DTI

What does Fiber tractography (FT) do?

. Actual fiber tracts of the brain and spine

What does DTI tractography visualize?

. Corpus callosum

Which fiber tract connects the right and left cerebral hemispheres?

. Arcuate fasciculus

Which fiber tract connects Wernicke’s and Broca’s area?

. Indicates different tracts

What does the colorful presentation of DTI tractography indicate?

. Brain tumor surgery

What is an indication for the use of DTI tractography?

. To avoid tracts and normal structures

How is tractography used in brain tumor surgeries?

. Magnetic Resonance Spectroscopy (MRS)

Which imaging modality exploits the different resonance characteristics of atomic nuclei to detect biochemical metabolites?

. Detect certain biochemical metabolites in the brain

What does MRS do?

. Analyzing the chemical composition of a selected brain region

What is MRS a non-invasive tool for?

. Differentiate types of masses (ex. Infection vs. tumor)

How can MRS be used clinically?

. N-acetylaspartate (NAA), choline, and creatine

What are important metabolites seen in MRS?

. Changes in these concentrations may indicate pathology

What might changes in metabolite concentrations seen in MRS indicate?

. Neurosonography

Which imaging modality involves using high-frequency sound waves to visualize the brain?

. Neonates

Who is neurosonography commonly used for?

. Due to the hyperechoic characteristics of the cranium

Why is neurosonography commonly used in neonates?

. The probe is placed on the fontanelle

Where is the probe placed during neurosonography on a neonate?

. Hydrocephalus (build-up of CSF in the ventricular system)

What is neurosonography indicated for in neonates?

. Assess the integrity of the cerebral vasculature

What can Doppler studies performed during neurosonography assess?

. Assess post-craniotomy patients for cerebral vasospasm

What specific use of Doppler studies in neurosonography is mentioned?

. Fluorodeoxyglucose Positron Emission Tomography (FDG PET)

What is a type of nuclear imaging modality that analyzes metabolic activity of specific brain areas?

. To detect abnormal glucose metabolism rates

What do tracer molecules like FDG in PET detect?

. Characterize and localize brain tumors

How can analysis of abnormal glucose metabolism using FDG PET be used?

. Cancer cells use more energy, thus needing more sugar

Why is abnormal glucose metabolism relevant for detecting brain tumors?

. Fluid Attenuated Inversion Recovery (FLAIR)

What is an imaging contrast technique applied to T2-weighted MRI scans?

. Produce an image with high contrast between gray and white matter, clear white matter and vasculature, and suppressed cerebrospinal fluid signal

What does FLAIR produce?

. Suppressed cerebrospinal fluid signal

What is a key characteristic of FLAIR imaging?