Face and Neck Imaging Flashcards
1
Q
Imaging modalities of the face
A
-Plain Xrays-CT-Ultrasound
2
Q
Plain films of the face
A
- Rarely ordered, CT is far superior, ordered anyway. Usually ordered if no CT
- Advantages: fast, less radiation, cheap
- Disadvantages: poor detail, overlap = easy to miss pathology
- 4-views standard: AP, lateral, Water’s view (money), submental vertex view (“jughandle” view)
- Nasal bone: single lateral view
- Looking for: Symmetry, Fluid collections, FB’s, Fractures, depressions
3
Q
CT of the face indications
A
- Indications: Significant trauma, Fracture present or suspected, Infections (Sinusitis, Periorbital cellulitis, Retrobulbar pus, Cavernous sinus thrombosis)
- CT usually first test
- Detail, clarity are far superior to plain film
- Sagittal, coronal, axial recons – standard
- Maxilo-facial views, Orbits thin cuts - these are specially ordered
4
Q
Blow out fracture
A
- “blow out” fracture - fx of bony orbit with “tear drop” sign (orbital fat) on plain film
- CT - blood, fat opacifies maxillary sinus
- suspect it post trauma to the orbit. If the affected eye EOM’s impaired, they have double vision and/or pain on looking up or out – suspect “entrapment” – when the orbital muscle or orbital fat is stuck in the fracture. Most commonly affected orbital muscle is the inferior rectus. If you get a plain film, this fx is best visualized on Water’s view. CT of the face and orbits follows plain film anyway – now days. It is first choice in most institutions. Orbital “cuts” are special and must be ordered separately – they are thin “slices” – 1-1.5mm.
5
Q
Nasal Trauma - CT v. Xray
A
- CT is clearly superior to plain film in outlining anatomy, surrounding structures
- Plain films of the nose are not routinely ordered. Only ordered if VERY minor injury. If significant swelling, deformity and/or suspected associated injury, order a CT instead.
6
Q
Tripod and LeFort Fractures
A
- Fractures involving maxilla, zygoma and orbit. NOT subtle
- Tripod fractures –> Direct blow to cheek, Zygomatic arch, orbit, wall of max sinus, CT initial study
- LeFort fractures –> Significant mechanism, 3 basic types, Maxilla or maxilla plus maxillary sinus/orbits/nose/arch in various degrees, CT initial study
- if you suspect one of these, you need CT, NOT XRAY
7
Q
Mandible
A
- Panorex – 1 view
- Plain film series used less – 3 views (AP, 2 lateral)
- CT if fracture, OMFS specialists request CT
- Describe: Location & number of fx’s, Open or closed, Distraction (separation)
- OMFS = oral maxillofacial surgeons
8
Q
Mandible plain films
A
- rarely ordered unless no Panorex or CT
- AP and 2 lateral views standard
- mandible often fractures in >1 place due to shape
9
Q
Facial CT - facial infection
A
CT is the diagnostic test of choice for suspected deep space infections involving the face, mouth, neck
10
Q
The cervical spine
A
- Plain film: may be useful as initial study for non-trauma neck pain, mild radicular pain, very minor trauma, persistent neck sx’s
- Plain films not ordered if significant trauma. CT first (unless no CT), great for bone-MRI for spinal cord injuries, radiculopathy
- Indications for CT imaging in trauma (NEXUS, Canadian Rules, etc…, Significant mechanism, Midline pain, Any paresthesia/numbness/weakness, Cannot rotate or flex w/o pain, ALOC/intoxication, Age >65)
11
Q
Plain films: neck
A
- 3 views standard - AP, lateral (money), open mouth odontoid view
- lateral is most useful: 85% fx’s seen here-odontoid view: specifically for C1, C2
12
Q
Plain Xray: AP, Water’s view
A
- lots of overlap, easy to miss fractures
- OK for opacified sinuses, foreign bodies
13
Q
Lateral and submental vertex view
A
- submental vertex or “jughandle” view
- best for suspected zygomatic arch fxs
14
Q
how to tell if its pus or blood on plain film
A
-ASK RADIOLOGIST FOR HOUNDSFIELD UNITS
15
Q
Lateral Neck Films
A
- is the film adequate?
- must be able to see the anterior superior corner (top of) T1 below C7 to evaluate alignment
- must see base of skull
- must see tips of C6, C7 spinous processes
- cant get view of C7-71? Get a swimmer’s view (one arm up)
16
Q
Swimmer’s view
A
- When unable to see entire cervical vertebral column AND/OR anterior corner (top) of T1 on lateral view
- Body habitus, disability, injury, etc.
- Goal: to see C7/T1 and see if they line up
- Technique: lateral with one arm above head
17
Q
reading lateral films
A
- Systematic Approach
- Count: ensure you can see the bottom of C7, top of T1
- Check 4 lines of alignment
- Look for consistent height/shape of vertebrae
- Look for consistent disc spaces between bones
- Look at soft tissue contours and spaces – measure if in doubt
- Check all spinous processes for fx
- Prevertebral Soft Tissues and Pre-dental Space
- Edema signals fracture/trauma
- Look at contour; measure (<6mm at C2, <5mm at C3/4, <22mm at C6, Kids: < ½ width VB)
- Pre-dental space (atlanto-dens interval) (< or = 3mm adults, < or = 5mm kids)
18
Q
lateral: alignment
A
1. Anterior longitudinal ligament line Anterior vertebral line 2. Posterior longitudinal ligament line Posterior vertebral line 3. Spinolaminar line 4. Spinous process line
19
Q
AP view
A
- Alignment
- Disc spaces
- Height, contour of vertebral bodies
- Spinous processes
- Transverse processes
20
Q
reading the odontoid view
A
- Do the vertebral bodies of C1 and C2 line up?
- Look at symmetry of spaces between C1 and C2 (Is the pt rotated? Radiologist)
- Look at contour of odontoid (dens) itself (Can you see the entire dens?)
- Check lateral for clues too!
21
Q
Special neck views
A
Oblique views (Neural foramina, facet joints, Less common, CT (fx) or MRI (cord) are far superior)
Flexion/Extension Views (Less common, NOT used in trauma, Controversial, CT/MRI superior)
22
Q
CT neck, cervical spine
A
-No contrast for fracture
-Great for bone, not great for spinal cord
-Reconstructions
-Indications (Trauma, Suspect fracture/dislocation, Fracture/dislocation present on plain xray, Deep space infection, abscess ->
Mass
23
Q
MRI cervical spine
A
- Definitive study for: Spinal cord injury, Radiculopathy, Abscess, Tumor, Pre-surgery
- GET SCAN 1ST, THEN MRI
24
Q
Neck Fractures
A
- 50% motor vehicle accidents, 25% falls, 10% sports
- Mechanism important – flexion, extension, axial load, distraction, compression
- Stable or Unstable fracture?
- Look for misalignment, soft tissue swelling, uneven disc spaces
- Significant trauma, ALOC, neuro deficit – CT all
- CT best for bone detail, MRI for spinal cord injury
25
Odontoid fractures
- Exact mechanism unknown: combination
- Odontoid fractures are unstable
- Quite often, the patient is also unstable
- CT when stabilized, MRI follows
26
Jefferson Fracture
- Fracture of the ring of C1
- Best seen on odontoid view
- C1 lateral masses are not lined up with C2 vertebral body
- Increased or uneven spacing between C1 and odontoid
- Mechanism: axial load
- Unstable fracture
- CT when stabilized, MRI follows
- Confirm all fractures on CT scan by looking at image above and below for consistency
27
Hangman's fracture
-Mechanism: hyperextension and compression
(face vs. windshield)
-Soft tissue edema
-C2 often seen “over-riding” C3 – subluxed
-Spinal cord damage at C2 common
-Unstable fx
-CT when stabilized, MRI follows
-True “judicial” hangman’s fracture is not the fracture above. When hanged, traditionally - with a long drop and the knot lateral – there is complete transection of the spinal cord
28
Burst fracture
- Mechanism: axial load compression
- Vertebral body in multiple pieces
- Posterior elements enter spinal canal, compromise spinal cord
- Unstable fracture
- CT when stabilized, MRI follows
29
Wedge Compression Fx
- Mechanism: hyperflexion with axial load compression
- Anterior vertebral body compressed into a “wedge”
- If posterior elements intrude on spinal canal, considered a burst fx
- Unstable fracture
- CT when stabilized, MRI follows
30
Flexion teardrop fx
- Mechanism: hyperflexion and compression
- Ligamentous disruption avulses bone – disruption can cause cord compromise
- Widening of facet joint and/or spinous process spacing
- Unstable fracture
- CT when pt is stabilized, MRI follows
31
Subluxation, Jumped or "perched" facets
- Mechanism: hyperflexion with distraction
- +/- Fracture w/ subluxation
- Perched facets is essentially a ligamentous injury
- Anterior and posterior vertebral lines of alignment are off
- Cord compromise possible
- Unstable
- Describe: top vertebrae is “subluxed onto” the lower one - % of vertebral body
32
Anterior Avulsion Fx
- Mechanism: hyperextension
- Anterior corner of vertebral body avulsed off by ligament tear
- Hyperextension itself may squish and damage cord
- Usually unstable
- CT all when stabilized
33
Clay Shoveler's and Spinous Process Fxs
- Clay Shoveler’s: spinous process fx at C6 or C7
- Mechanism: Sudden hyperflexion; clay stuck to shovel when tossing overhead.
- Also caused by a direct blow to area.
- Classically, a ligamentous avulsion. Usually stable
34
Neck: soft tissue lateral
- Special view – must request it
- Do not need C7/T1 – but nice to have it
- Useful for epiglottitis, retropharyngeal abscess, swallowed foreign bodies
- Exposure is underpenetrated to highlight the soft tissues
- Lateral is only useful soft tissue view
- CT scan often ordered first
- CT scan ordered first with high suspicion, any mass, unstable patient
35
Epiglottitis
- Soft tissue lateral ok as first test unless high suspicion – then get a CT first as is definitive
- Do not need C7/T1
- Epiglottis is an anterior structure, usually a thin fingerlike soft tissue density at level of the hyoid bone
- See enlarged epiglottis, classic “thumb” sign
- Classic presentation: man with no IMZs and grew up outside US and has thumb sign
36
Retropharyngeal abscess
- Kids, adults too
- Fever, severe sore throat, trismus (cant open mouth properly), anterior neck pain, pharyngeal findings don’t match
- See soft tissue edema/mass in retropharyngeal space
- Soft tissue lateral ok unless high suspicion
- CT when stable for detail, extent
37
Imaging thyroid nodules/masses
- Ultrasound is initial imaging test: Size, composition, US-guided fine needle aspiration (FNA) biopsy, US alone cannot be relied upon to dx cancer (need biopsy)
- Thyroid scintigraphy: Nuclear medicine study, Determines the functional status of a nodule (warm/hot/cold), No longer initial test, Low TSH plus nodule
- CT reserved for complex cases, eval adjacent structures
38
Vascular Studies - neck
- Duplex Ultrasound -> Carotid/vascular flow, Part of CVA work up
- CT angiography (CTA): CVA, carotid dissection, trauma
- 3-D (enhanced) CT angiography
- MR angiography (MRA)
- Traditional angiography: Plain film after dye, Used less – CT or MRA preferred for detail
