Imaging of the Paranasal Sinuses - orl-hno.ch .Nervus opticus Nervus maxillaris Nervus vidianus

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Text of Imaging of the Paranasal Sinuses - orl-hno.ch .Nervus opticus Nervus maxillaris Nervus vidianus

Imaging of the Paranasal Sinuses

Bettlach

24.08.2018

14. Sommerschule

Christoph Schlegel

https://www.orl-hno.ch/home.html

Christoph Schlegel Sommerschule 2018

Conventional Radiology

NNH-Status: okzipito-frontal: frontal sinus, anterior ethmoid

okzipito-nasal : maxillary and frontal sinus

axial: sphenoid and ethmoidal sinus

Radiation exposure:

2 mGy per exposure

(dose for cataract 2 Gy)

Christoph Schlegel Sommerschule 2018

Conventional Radiology

inadequate sensivity and specifity

superseded by CT

Single detector row CT

2 Zeilen 1990

4 Zeilen 2000

8 Zeilen 2002

16 Zeilen 2004

64 Zeilen 2005

2x 64 Zeilen 2006

2x 128 Zeilen 2009

Multi detector row CT

4

16

Multislice Spiral CT

Christoph Schlegel Sommerschule 2018

Paranasal Sinus CT Protocol

high resolution axial scan from alveolar process to frontal sinus

collimation 0.6mm

overlapping slice reconstruction 0.6/0.4mm, mAs

Christoph Schlegel Sommerschule 2018

Review: Radiation Dose

radiation dose paranasal sinus CT 0.5-1mGy

conventional x-ray paranasal sinus 0.2 mGy/expos.

average diagnostic dose /per capita CH: 1mGy, GB 0.33mGy

transatlantic flight (round trip) 0.1mGy

cataract of eye lens: > 2 Gy

Christoph Schlegel Sommerschule 2018

preoperative anatomy, residual mucosal disease

pattern of bone destruction, skull base defects

navigation- CT , CT guided biopsies

CT

MRI

soft tissue differentiation: retention, tumor, cellularity,

vascularity

meningeal, neural, vascular involvement

Christoph Schlegel Sommerschule 2018

Complementary Role CT MR

Christoph Schlegel Sommerschule 2018

Meningo-Encephalocele

Christoph Schlegel Sommerschule 2018

Christoph Schlegel Sommerschule 2018

Clival Chordoma

Christoph Schlegel Sommerschule 2018

Angiography

diagnostic use for selected cases

superselective embolisation: intractable epistaxis; M. Osler

embolisation of tumors

Christoph Schlegel Sommerschule 2018

Juvenile Nasopharyngeal Angiofibroma

Christoph Schlegel Sommerschule 2018

Orbital Complication: Subperiostal Abscess

Christoph Schlegel Sommerschule 2018

Endocranial Complikation: Epidural and Soft Tissue Abscess in Frontal Sinusitis

Christoph Schlegel Sommerschule 2018

Chronic Rhinosinusitis (without Nasal Polyps)

N.B.: after medical treatment

Christoph Schlegel Sommerschule 2018

Chronic Rhinosinusitis (with Nasal Polyps)

N.B.: after medical treatment

Christoph Schlegel Sommerschule 2018

Red Flags

Consider other diagnosis:

unilateral symptoms

bleeding, crusting

cacosmia

orbital symptoms( oedema, displaced globe, double

vision)

severe frontal headache, frontal swelling

signs of meningitis

neurological signs

urgent investigation and intervention

Christoph Schlegel Sommerschule 2018

Granulomatose mit Polyangiitis (M. Wegener)

Christoph Schlegel Sommerschule 2018

Aspergilloma (fungus ball)

Christoph Schlegel Sommerschule 2018

Odontogenic Sinusitis

Christoph Schlegel Sommerschule 2018

Inverted Papilloma

Christoph Schlegel Sommerschule 2018

Inverted Papilloma

Christoph Schlegel Sommerschule 2018

Mucocele of Maxillary Sinus

Christoph Schlegel Sommerschule 2018

Mucocele of Sphenoid Sinus

Dehiscent Internal Carotid Artery

Christoph Schlegel Sommerschule 2018

Complicated Nose Fracture

Christoph Schlegel Sommerschule 2018

Zygomatic Fracture

Christoph Schlegel Sommerschule 2018

CSF-Leak

High resolution CT

MRI (T2)

2-transferrin or -trace

In selected cases: Intrathecal fluorescein injection

Christoph Schlegel Sommerschule 2018

CSF-Leak

Christoph Schlegel Sommerschule 2018

Dacryo CT Scan

Christoph Schlegel Sommerschule 2018

Dacryo CT Scan

Christoph Schlegel Sommerschule 2018

FESS: Preoperative Evaluation (CT Checklist)

uncinate process

ethmoidal roof, skull base

ethmoidal arteries

orbit, optic nerve

internal carotid artery

anatomical variations of ethmoidal cells

Christoph Schlegel Sommerschule 2018

Uncinate Process

Simmen D, Jones N: Manual of Endoscopic Sinus Surgery. Thieme 2014

A B1 B2

Christoph Schlegel Sommerschule 2018

Preoperative Checklist: Uncinate Process

Typ A (~ 75%): Insertion at Lamina

papyracea

Recessus terminalis

Frontal sinus drainage

pathway directly in middle

meatus

Christoph Schlegel Sommerschule 2018

Preoperative Checklist: Uncinate Process

Typ B1: Insertion at skull base

Frontal sinus drainage

pathway in ethmoidal

infundibulum

Christoph Schlegel Sommerschule 2018

Preoperative Checklist: Uncinate Process

Typ B2: Insertion at middle turbinate

Frontal sinus drainage

pathway in ethmoidal

infundibulum

Wormald PJ: The agger nasi cell: the key to understand the anatomy of the frontal recess Otolaryngol Head Neck Surg 2003; 129:497-507

Frontal Recess

Anatomy of the Frontal Recess

"frontal drainage pathway"

"fronto-ethmoidal cell"

"agger nasi cell"

Frontal Recess: Sagittal Reconstruction

Fronto-ethmoidal cells:

Agger nasi cell

K1 to K4 cells

Suprabullar cells

Frontal bullar cells

Interfrontal sinus septal cell

Christoph Schlegel Sommerschule 2018

Christoph Schlegel Sommerschule 2018

anterior

posterior

(medial)

Christoph Schlegel Sommerschule 2018

Preoperative Checklist: Ethmoid Roof Cribriform Plate

Preoperative Checklist: Anterior Ethmoidal Artery

Preoperative Checklist: Optic nerve

Preoperative Checklist: Internal Carotid Artery

Concha bullosa media

Haller Cell

Haller Cell

Onodi Cell

Pneumatized Inferior Turbinate

3 Nervs ???

Nervus opticus

Nervus maxillaris

Nervus vidianus

Cone Beam CT (Digitale Volumentomographie)

http://www.google.ch/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjl3qnygb3cAhXJ_aQKHQAxBmMQjRx6BAgBEAU&url=http://newtom.dev.cefla-srv.redturtle.it/en/products/newtom-5g&psig=AOvVaw2JgpwTR96Zf0OvKT3DMHd9&ust=1532703021936826

Christoph Schlegel Sommerschule 2018

Cone Beam CT

Corresponds to a C-arm with 3D images

Digital volume tomography

Cone revolves around patient for 360

Since 2000

Office use, no need for a radiologist

Christoph Schlegel Sommerschule 2018

Low dose multislice CT Cone beam CT

MSCT DVT

Acquisition time ( motion artefacts)

2 sec 20-40 sec

Radiation exposure 0.2-0.5 mSV (+ 30-40%)

0.1-0.3 mSV

Image homogenity + +

Bone window Soft tissue window

+ +

+ -

Cost - +

Image reconstruction + +

De Cock et al. A comparative study for image quality and radiation dose of a cone beam computed

tomography scanner and a multislice computed tomography scanner for paranasal sinus imaging.

Eur Radiol (2015) 25:18911900

Al Abduwani et al. Cone beam CT paranasal ainuses versus low dose meltidetector CT studies.

Am J Otolaryngol (2016)37:59-64

Navigation: Localization Systems

Optical tracking systems Electromagnetic tracking systems

+ cordeless + free movement of surgeon

- line of sight - magnetic interference

Christoph Schlegel Sommerschule 2018

Accuracy

Depends on: CT scan and its reconstruction

Registration !

Patient motion, motion of reference points !

Generally accepted range: 1 mm (=2 mm)

Shift in accuracy from anterior to posterior

up to 9 mm (z axis)

Intraoperative Manual Registration Refinement

New feature to adjust disaccuracy i.e. in the depth

Before After

Navigation starts the day before surgery by:

Analysis of the CT-scan (coronar,axial,sagittal):

where is the frontal drainage pathway?

Step by step surgical plan

Christoph Schlegel Sommerschule 2018

Suggested Reading

Simmen D, Schuknecht B: Computed tomography of paranasal sinuses.

A preoperative checklist. Laryngo-Rhino-Otology 1997; 76:8-13

Simmen D