Sinuses, Facial Bones, Cerebral Vasculature Flashcards
What are indications for Sinus CT
Inflammatory sino/nasal disease, Chronic sinusitis, roadmapping for surgery
What is the focus of sinus CT anatomically
Frontal, ethmoid, sphenoid, and maxillary sinuses as well as nasal passages, turbinates, and septum
What are the benefits of Sinus CT
Screening is inexpensive, low radiation, and accurate
What is the more common scan plane for sinuses: Coronal or Axial
Axial supine
What is the scan range for sinuses
From above the frontal sinus to below the hard palate including from mid sella through frontal sinus
How do you position a patient for sinuses
Supine (sometimes prone), extend the chin and drop head as far back as possible in a special head holder.
Align hard palate perpendicular to the table (OML line) OR angle the gantry if not possible
Do you use CM for sinuses
no
What are you trying to demonstrate in chronic sinusitis coronal axial image
air-fluid level
What is the preferred modality for imaging of the face
CT. It is most sensitive for fracture detection
What is a disadvantage of CT imaging for the face
It has potential to miss a subtle tooth fracture along the axial plane
What are some indications for a non-enhanced face ct
facial fractures and soft tissue injury
What are some indications for an enhanced ct scan of the face
Infection and masses
Is face CT axial or helical
Helical: crucial to make accurate reconstructions!
If contrast IS used, will it be single or split bolus
Split
Romans says position patient head how
chin tucked
How will some techs opt to position patient
angle gantry parallel to the IOML
What is the most likely vasculature of interest for CTA of the face/head
Circle of Willis (COW)
When performing CTA of COW how many scans will be performed
2 sets:
1 non contrast head
second arterial phase CTA with 80ml @ 4ml/s OR 60ml if the concentration is higher than 370 with 20ml of saline
For a timed bolus of COW CTA what level will you place the ROI
Carotid artery at C4
What is the scan range for CTA COW
Level of C1 to just above skull vertex (may differ in clinical)
What will happen if one of the main arteries making the COW is occluded
The distal smaller arteries may begin receiving collateral circulation
What are some indications for CT Venography (CTV)
Cerebral venous disorders, dural sinus thrombosis
What is the contrast required for CTV
100ml at 4ml/s on a 45 s delay
What is the scan range for CTV
just below skull base to just above vertex
How do you position the patient for CTV
Hard palate perpendicular to the table top
