CT Imaging of Head and Neck Flashcards by Denina Martinito

BRAIN IMAGING
Examples of clinical indications
- Without contrast:

intracranial hemorrhage, early infarction, dementia, hydrocephalus, cerebral trauma

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BRAIN IMAGING
Examples of clinical indications
- Without and with contrast:

Mass, lesion, arteriovenous malformation, metastasis, aneurysm, for symptoms of headache, seizure

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BRAIN IMAGING Scout

AP and lateral

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BRAIN IMAGING Scan type

Axial

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BRAIN IMAGING Scan plane

Transverse

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BRAIN IMAGING Start location

Just below skull base

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BRAIN IMAGING End location

Just above vertex

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BRAIN IMAGING IV contrast

100 mL at 1.0 mL/s

Scan delay = 5 minutes

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BRAIN IMAGING Oral Contrast

None

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BRAIN IMAGING Reference Angle

Angle gantry parallel to supraorbital meatal line (avoid lens of eyes)

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BRAIN IMAGING SFOV

Head

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BRAIN IMAGING Algorithm

Standard

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BRAIN IMAGING Window settings

140 ww/40 wl

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BRAIN IMAGING Gantry rotation time

2.0 s or 1.0 s depending on the CT scan

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BRAIN IMAGING Reconstruction (slice thickness/interval)

5.0 mm/5 mm (2 images per rotation)

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BRAIN IMAGING kVp/mA (posterior fossa)

140/150

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BRAIN IMAGING kVp/mA (vertex)

120/150

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BRAIN IMAGING Reconstruction 2:

Algorithm: Bone
Window setting: 4000 ww/400 wl
DFOV: ∼23
Slice thickness/interval 2.5 mm/2.5 mm

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Lens shaped (dura tightly adhered to skull
Can cross midline
Frequently assoc. with fracture

Epidural Hematoma

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Follows the contour of the brain & doesn’t cross the midline

Subdural Hematoma

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TEMPORAL BONE IMAGING Examples of clinical indications

- Without contrast:

cholesteatoma, inflammatory disease, fractures, evaluate implants

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TEMPORAL BONE IMAGING Examples of clinical indications

- With contrast:

IAC tumor, hearing loss, acoustic neuroma, Schwannoma

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TEMPORAL BONE IMAGING Scout

AP and lateral

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TEMPORAL BONE IMAGING Scan type:

Axial

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TEMPORAL BONE IMAGING Scan plane:

Transverse

TEMPORAL BONE IMAGING Start location

Just below the mastoid process

TEMPORAL BONE IMAGING End location

Just above petrous ridge (include entire mastoid, internal auditory canal, and external auditory canal)

TEMPORAL BONE IMAGING IV contrast

(if contrast is ordered) 100 mL at 1.0 mL/s. Scan delay = when all contrast is administered

TEMPORAL BONE IMAGING Oral Contrast

None

TEMPORAL BONE IMAGING Reference Angle

Angle gantry parallel to infraorbital meatal line (be sure patient’s head is straight and not rotated in the head holder)

TEMPORAL BONE IMAGING DFOV

~ 9.6cm

TEMPORAL BONE IMAGING SFOV

Head

TEMPORAL BONE IMAGING Algorithm

Bone

TEMPORAL BONE IMAGING Window settings

4000ww/400wl

TEMPORAL BONE IMAGING kVp/mA

140/170

TEMPORAL BONE IMAGING Gantry rotation time

1.0s

TEMPORAL BONE IMAGING Reconstruction (slice thickness/interval):

0.625 mm/0.625 mm

TEMPORAL BONE IMAGING Reconstruction 2:

Algorithm: Bone Window setting: 4000 ww/400 wl DFOV: ∼9.6 cm Slice thickness and interval: 0.625 mm/0.625 mm

is intended as an inexpensive, accurate, and low radiation dose method for confirming the presence of inflammatory sinonasal disease

Sinus screening

PARANASAL SINUSES(SCREENING) CT scans typically obtained for visualizing the paranasal sinus should include

coronal and axial (3-mm) cross sections

In Paranasal Sinuses Screening, _____ facilitate evaluation of disease processes and the bony architecture.

Soft tissue and bony windows

In Paranasal Sinuses Screening, the use of ____ just prior to scanning can help define soft tissue lesions and delineate vascularized structures, such as vascular tumors.

Intravenous constrast material

Contrast-enhanced CT is particularly useful in evaluating

neoplastic, chronic, and inflammatory processes.

PARANASAL SINUSES SCREENING | Examples of clinical indications:

Recurrent or chronic sinusitis

PARANASAL SINUSES SCREENING | Scout

Lateral

PARANASAL SINUSES SCREENING | Scan type

Axial

PARANASAL SINUSES SCREENING | Scan plane

Coronal

PARANASAL SINUSES SCREENING | Start location

Mid sella

PARANASAL SINUSES SCREENING | End location

Through frontal sinus

PARANASAL SINUSES SCREENING | IV contrast

none

PARANASAL SINUSES SCREENING | Oral contrast

none

PARANASAL SINUSES SCREENING | Reference angle

Angle gantry perpendicular to the orbital meatal line

PARANASAL SINUSES SCREENING | DFOV

16 cm

PARANASAL SINUSES SCREENING | SFOV

Head

PARANASAL SINUSES SCREENING | Algorithm

Standard

PARANASAL SINUSES SCREENING | Window settings

350ww/50wl

PARANASAL SINUSES SCREENING | Reconstruction (slice thickness/interval):

2.5mm/2.5mm

PARANASAL SINUSES SCREENING | kVp/mA

120/150

PARANASAL SINUSES SCREENING | Reconstruction 2:

Algorithm: Bone Window setting: 4000 ww/400 wl DFOV: ∼23 Slice thickness/interval 2.5 mm/2.5 mm

FACIAL BONES | Examples of clinical indications:

Characterization of facial fractures and soft tissue injury

FACIAL BONES Scouts

AP and lateral

FACIAL BONES Scan type

Helical

FACIAL BONES Scan plane

Transverse

FACIAL BONES Start location

Just below mandible

FACIAL BONES End location

Just above frontal sinus

FACIAL BONES IV contrast

none

FACIAL BONES Oral contrast

none

FACIAL BONES Reference angle

Angle gantry parallel to infraorbital meatal line

FACIAL BONES DFOV

18 cm

FACIAL BONES SFOV

Head

FACIAL BONES Algorithm

Standard

FACIAL BONES Window settings

350ww/50wl

FACIAL BONES Gantry rotation time

0.8s

FACIAL BONES Reconstruction (slice thickness/interval)

1.24 mm/0.625 mm

FACIAL BONES Pitch

0.562

FACIAL BONES kVp/mA

120/250

FACIAL BONES Reconstruction 2

Algorithm: Bone Window setting: 4000 ww/400 wl DFOV: 18 Slice thickness/interval: 1.25 mm/0.625 mm

Tripod Fracture

Zygomatic-frontal suture Zygomatic arch Maxillary sinus wall

Routine scanning of the neck is typically performed with the patient in

supine and the neck slightly extended

Neck scanning is most often performed in the

Helical mode

To reduce artifacts that degrade images in the lower neck, the patient should be instructed to

lower the shoulders as much as possible

The goals in CT scanning of the neck are

to allow sufficient time after contrast administration for mucosa, lymph nodes, and pathologic tissue to enhance, yet acquire images while the vasculature remains opacified

NECK IMAGING | Examples of clinical indications:

Neck mass, vascular abnormality | If patient has metal dental work, split scan into two groups and angle to reduce artifact

NECK IMAGING Scouts

AP and lateral

NECK IMAGING Scan type

Helical

NECK IMAGING Scan plane

Transverse

NECK IMAGING Start location

Mid orbit

NECK IMAGING End location

Clavicular heads

NECK IMAGING IV contrast

125 mL at 1.5 mL/s. Split bolus—1st injection 50 mL, 2-minute delay; 2nd injection 75 mL, scans initiated 25 seconds after the start of the second injection.

NECK IMAGING Oral contrast

none

NECK IMAGING Reference angle

Angle gantry parallel to hard palate

NECK IMAGING DFOV

18 cm

NECK IMAGING SFOV

Large body

NECK IMAGING Algorithm

Standard

NECK IMAGING Window settings

350ww/50wl

``` NECK IMAGING (Cervical Spine) Examples of clinical indications ```

Fracture, dislocation

``` NECK IMAGING (Cervical Spine) Scouts ```

AP and lateral

``` NECK IMAGING (Cervical Spine) Scan type ```

Helical

``` NECK IMAGING (Cervical Spine) Scan plane ```

Transverse

``` NECK IMAGING (Cervical Spine) Start location ```

Just above skull base

``` NECK IMAGING (Cervical Spine) End location ```

Mid T1 (include all cervical spine vertebrae, unless a level is specified)

``` NECK IMAGING (Cervical Spine) IV contrast ```

(only when requested by radiologist) 100 mL at 1.5 mL/s. | Scan delay = when injection is complete

``` NECK IMAGING (Cervical Spine) Oral contrast ```

none

``` NECK IMAGING (Cervical Spine) Reference angle ```

No gantry tilt

``` NECK IMAGING (Cervical Spine) DFOV ```

~ 13cm

``` NECK IMAGING (Cervical Spine) SFOV ```

Large body

``` NECK IMAGING (Cervical Spine) Algorithm ```

Standard

``` NECK IMAGING (Cervical Spine) Window settings ```

350ww/50wl

``` NECK IMAGING (Cervical Spine) Gantry rotation time ```

0.8s

``` NECK IMAGING (Cervical Spine) Reconstruction (slice thickness/interval) ```

2.50mm/1.25mm

``` NECK IMAGING (Cervical Spine) Pitch ```

0.562

``` NECK IMAGING (Cervical Spine) kVp/auto mA ```

140/125-325

``` NECK IMAGING (Cervical Spine) Reconstruction 2 ```

Algorithm: Bone Window setting: 4000 ww/400 wl DFOV: ∼13 cm Slice thickness/interval: 2.5 mm/1.25 mm

``` NECK IMAGING (Cervical Spine) Reformations ```

Coronal and Sagittal

``` NECK IMAGING (Cervical Spine) Algorithm ```

Bone

``` NECK IMAGING (Cervical Spine) Window setting ```

4000ww/400wl

``` NECK IMAGING (Cervical Spine) DFOV ```

Full

``` NECK IMAGING (Cervical Spine) Slice thickness/spacing ```

2.0mm/2.0mm

CT angiography advantages: - The time-saving nature of CTA over traditional angiography is particularly important in the case of patients suspected of suffering an acute stroke in which treatment decisions must be made quickly.

noninvasive and widely available

The goals of CTA for cervicocranial vascular evaluation:

1) to accurately measure stenosis of the carotid and vertebral arteries and their branches, 2) to evaluate the circle of Willis for completeness using three-dimensional reformations of cerebral vasculature in relation to other structures, 3) to detect other vascular lesions, such as dissections or occlusions.

used for the depiction of venous anatomy

CT venography (CTV)

Scan parameters for CT venography are quite similar to CTA, except images are acquired while contrast is in

the venous enhancement phase.

CT Imaging of Head and Neck Flashcards

(122 cards)