Transcript OCULAR Ultrasound - Autumn Symposium

OCULAR
Ultrasound
Scott Stirling, MD(MBBS),
FACEM, ABEM,
RDMS,CCPU
How to perform ocular USS
• Use a high resolution linear transducer with ocular preset
• Use protection to the eye: a Tegaderm works fine
• Apply a large amount of ultrasound gel to patient’s closed eyelid so that the
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transducer doesn’t have to touch the eye
Adjust depth so that the eye fills the screen
Examine in moderate and high gain settings
Scan both eyes in sagittal and transverse planes
Ask patient to look straight ahead with eyes closed, don’t clench the eyelids
Ask the patient to look up, down, left and right
Anatomy
Anatomy
● Circular hyperechoic structure
● Cornea is thin hypoechoic layer
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Normal eye
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parallel to the eyelid
Anterior chamber is filled with
anechoic fluid, bordered by cornea,
iris and anterior reflection of lens
Normal lens is anechoic
Normal vitreous chamber filled with
anechoic fluid
Optic nerve is seen posteriorly
Clinical Uses
● Eye trauma
● Suspected foreign body
● Acute change in vision
● Eye pain
● Evaluating for consensual light reflex in severe periorbital oedema
● Suspected raised intracranial pressure
Pitfalls and contraindications
● Ruptured globe
● Relying solely on ONSD to make clinical decisions
● Mistaking a posterior vitreous detachment for a retinal
detachment…
● … or vice-versa
● Mistaking a macular on retinal detachment for a macular
off retinal detachment…
● … or vice-versa
Normal Eye
Consensual Light Reflex
Retrobulbar Haematoma
● Retrobulbar haematoma
● Guitar pick sign
● Not very sensitive
Globe Rupture
● Decreased globe size
● Anterior chamber collapse
● Buckling of the sclera
Foreign Body
• Bright hyperechoic foreign body
• Shadowing or reverberation artefacts
Lens Dislocation
• Result of trauma or idiopathic
• Displaces anteriorly or posteriorly
• If partially dislocated may look normal
until eye is moved
• May be evidence of other pathology
Vitreous Haemorrhage
• Images vary depending on age and
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severity of haemorrhage
Appears as echogenic material in
posterior chamber
Fresh = small dots of mobile vitreous
opacities
Severe/old = membranes
May layer inferiorly due to gravity
Vitreous Haemorrhage
https://www.youtube.com/watch?v=z8_GLOPZ2aU
Retinal Detachment
• Thick hyperechoic undulating
membrane in the posterior or
lateral globe
• Does not occur at the site of the
optic nerve
• In total detachment the folded
surface attaches to the optic nerve
posteriorly and the ora serrata
anteriorly
Retinal Detachment
https://vimeo.com/108752397
Retinal Detachment
https://www.youtube.com/watch?v=PAJ5UomIm4w
Retinal Detachment
Macula On vs. Macula Off
https://www.youtube.com/watch?v=JijIfSzOG9U
Posterior Vitreous Detachment
• Fine linear and granular-appearing
echodensities in vitreous chamber
with very high gain
• C-shaped concave upward
appearance
• Swirling appearance when patient
moves eye
• Unlike retinal detachment in that:
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Occurs in front of optic disc and does not
remain anchored to it
Lacks a thickened hyperechogenic membrane
Posterior Vitreous Detachment
https://www.youtube.com/watch?v=PO5UsX506c0
Optic Nerve Sheath Diameter (ONSD)
Raised Intracranial Pressure
• Optic sheath diameter measurement
• Measure 3mm posterior to globe
• Normal diameter is ≤ 5mm
• Diameter >6mm raised ICP should be suspected
ONSD – Elevated ICP
Evidence – ONSD
Study
N
Best cut off value
(ONSD)
Sensitivity
Specificity
Soldaltos
32
5.7
74
100
Kimberly
15
5
88
93
Geeraerts
37
5.86
95
79
Rajajee
65
4.8
96
94
Cammarata
11
7 -
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ONSD – Paediatric Evidence
1. Hall et al10
39 encounters of VPS shunt failure
Mean ONSD: 4.5 +/- 0.9-no failure | 5.0 +/-0.6 with failure
Sensitivity 61.1%
2. Le et al9
N = 64
ONSD: 4.0mm cutoff < 1 year old | 4.5mm > 1 year old
sensitivity 83%, specificity 38%
Thanks
AIUM
Adrian Goudie - Ultrasound Village
Michelle Lin - ALiEM
USS special skills post
0.5FTE ultrasound shifts. 0.5FTE clinical shifts
Logan Hospital
Positions available for August 2017, Jan 2018
[email protected]
References
1. Ultrasound village : http://www.ultrasoundvillage.com/
2. AlieM: www.aliem.com
3. Theodoros Soldatos, Dimitrios Karakitsos, Katerina Chatzimichail, Matilda Papathanasiou, Athanasios Gouliamos, and
Andreas Karabinis Optic nerve sonography in the diagnostic evaluation of adult brain injury Crit Care. 2008;
4. Heidi Kimberly & Vicki E Noble. Using MRI of the optic nerve sheath to detect elevated intracranial pressure Crit Care.
2008; 12(5): 181.
5. Thomas Geeraerts,1,2 Jacques Duranteau,2 and Dan Benhamou. Ocular sonography in patients with raised intracranial
pressure: the papilloedema revisited Crit Care. 2008; 12(3): 150.
6. Rajajee V, Vanaman M, Fletcher JJ, Jacobs TL. Optic nerve ultrasound for the detection of raised intracranial pressure.
Neurocrit Care. 2011 Dec;15(3):506-15.
7. Cammarata G, Ristagno G, Cammarata A, Mannanici G, Denaro C, Gullo A. Ocular ultrasound to detect intracranial
hypertension in trauma patients.
J Trauma. 2011 Sep;71(3):779-81.
8. Hall MK, Spiro DM, Sabbaj A, Moore CL, Hopkins KL, Meckler GD.
Bedside optic nerve sheath diameter ultrasound for the evaluation of suspected pediatric ventriculoperitoneal shunt failure
in the emergency department. Childs Nerv Syst. 2013 Dec;29(12
9. Le A1, Hoehn ME, Smith ME, Spentzas T, Schlappy D, Pershad J. Bedside sonographic measurement of optic nerve
sheath diameter as a predictor of increased intracranial pressure in children. Ann Emerg Med. 2009 Jun;53(6):785-91