NEURORADIOLOGY



NEURORADIOLOGY

Dr. Ramirez

Imaging Examination:

Head:

1. Plain Radiographs

a. PA view

b. Lateral view

c. Towne’s view

d. Caldwell’s view

e. Water’s view

2. Contrast Examination

a. Arteriography

b. Pneumoencephalography- introducing an air

3. Ultrasound – fontanel, suture are fused; absence of window

4. CT Scan

5. MRI

6. Radioisotope studies

PA- frontal bones, frontal and ethmoid sinuses, nasal cavity cavity, superior orbital rims and mandible.

Lateral- frontal bone and paranasal sinuses

Towne’s- occipital bone, mastoid and inner ear region, foramen magnum and zygomatic arches

Submentovertical – basal structure of the skull including the major foramen.

PA View:

• Patient is in normal supine position

• Note outer and inner table (smooth)

• Vertex, temporal and partial area are of thinning density

Densities:

• Black- air (usually dark or loosen)

• White- bones, calcification

• Gray- soft tissue density

Lateral View:

• Ethmoid sinus beneath frontal or greater wing of sphenoid

• Frontal sinus

• Sphenoid sinus- beneath sella

• Maxillary sinus

Lobes (fossa)

Frontal lobe- anterior

Parietal lobe- middle

Cerebrum and pons- posterior

Petrous bone- ridge and anterior margin of posterior fossa

Lesser wing of sphenoid- anterior margin of the anterior fossa

Towne’s View:

• Foramen magnum

• Lambdoid (triangular)

Submentovertical View:

• Foramen magnum- lacerated

• Foramen ovale- round

Caldwells View:

• PA with little angulation

• Margin of orbit

• Temporal bone

AP View:

• Middle cerebral artery

Circle of Willis:

Anteriogram study:

Three phases of arteiography:

1. arterial

2. parenchymal

3. venous

Artery on left side

Anterior cerebral artery- midline; space occupying lesion

Displaced to the right- Focal hydrocephalus

Communicating- no obstruction; increase production of CSF

SKULL ABNORMALITIES:

1. Size

a. small (microcephaly)

• incomplete development

• craniostenosis

• pituitary abnormality

b. large (macrocephaly)

• hydrocephalus

• endocrine disorders (acromegaly)

• congenital or development (osteogenesis imperfecta)

• 2/4 skull- 1/3 face

2. Contour

• Craniostenosis

• Meningoencephalocoele

• Depressed fracture

Osteomas- benign, inc. density of bone

Platysbia- osteogenesis imperfecta

(paget’s disease, Arnold Chiari malformation)

3. Lucencies

• Fracture

• Infection (asteomyelitis)

• Neoplastic

• Metabolic/endocrine (hyperparathyroidism)

Fracture- dense

Margin is stenotic ordenser

4. Opacities or Densities

• Calcification- physiologic

• Congenital/development (osteoporosis, engelan’s dx)

• Teratoma- calcification, fat, air in soft tissue

HYDROCEPHALUS

• Posterior and anterior fontanel

• Wormians- vascular branching

Radiographic evidence of intracranial space occupying lesions:

1. increase convolutional impression

2. separation of sutures (up to about 14 to 15 years)

3. sella turcica changes

4. erosions of the bones of the skull

5. displacement of the physiologically calcified suture

• abnormal vascular grooves

• abnormal calcification within the lesion

Structures that are already calcified:

1. pineal gland- midline

2. choroids plexus- lateral

3. cerebral falx- midline

4. havinular commisure- midline

5. glenoid ligaments- area of sella

1-6 months old

• lukenchalden/lacunar skull

• hydrocephalus

caputsuccedaneum- cross behind suture lines

cephalhematoma- above calvareum; soft tissue

lytic- lucent lesion

blastic- sclerotic lesion

multiple densities:

-infant- osteocytosis

encephalocoele- brain and CSF

meningocoele- only brain parenchyma

havinular calcification- C calcification

pineal gland- round or ovoid calcification

Choroid plexus Calcification- “popcorn-like calcification”

Toxoplasmosis lesion in the parenchyma- parasitic

Frontal View of Sella:

• external auditory canal

• sphenoid

• dorsal sella

• 14 by 17- posterior sphenoid

• 1:17 cm

Radiographic evidence of sellar/ parasellar lesion:

Intrasellar lesion:

• thinning and deepening of sellar fossa

• thinning of backward bending of the dorsum sellae

• destruction of the bony walls of the sella (late stage)

Extracellular Lesion:

• sellar floor is thinned but not depressed

• dorsum sellae thinned out

CT Scan:

Dark: White:

1. fat- dark in CT scan 1. bone

2. fluid 2. calcification

3. air-dark 3. contrast

4.acute bleed

Magnetic Resonance Imaging (MRI)

Hydrogen Ion- align in the magnetic range

Two studies of CT Scan:

T1- on magnet- hydrogen ion synchronized

T2- off the magnet- measure how hydrogen ion is disoriented

Edema- lot of hydrogen ion

Trauma- plain study

Inflammatory- contrast study

TB meningitis- increase creatitine

Trauma patient:

Subdural hemorrhage- less dense than skull but denser than parenchyma

Epidural bleed- bulge toward parenchyma, do not follow the contour of brain

Subdural- follow the contour of the brain

Infarct- involving the basal ganglia

Internal capsule- divides external ganglia from thalamus

Abscess- ring enhancing lesion

Parenchyma and midline- middle blastoma

Spines:

1. AP

2. oblique

3. CT scan

4. MRI

5. arteriogram

6. Isotope studies

Intramedullary- spinal cord involved

Extramedullary and extradural- one side of the spinal cord

Contours:

Kyphosis- thoracic

Lordosis- lumbar

Spondylostasis- anterior displacement

Spondylosis- protruding in laminal parenchyma

Hemivertebra- one bone is undeveloped

Fused vertebra- intervertebral space absent

Scatty dog appearance:

Neck transverse process

Ear is pedicle and facet

Body is post vertebra

Legs inferior articulating artery

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