imaging of the larynx goalsdistribute.cmetoronto.ca/mim1202/1002-1030-bartlett-the... ·...
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Imaging of the Larynx
Eric S. Bartlett, MPH MD
www.HeadAndNeckRad.com
Assistant ProfessorNeuroradiology, Head and Neck DivisionJoint Department of Medical ImagingDepartment of Otolaryngology—Head and Neck SurgeryUniversity of TorontoPrincess Margaret Hospital
Goals:
• Describe basic function of larynx
• Define the role of imaging
• Review anatomy
• Identify squamous cell carcinoma (SCCa) & pitfalls.
• Introduction: Function / Embryology / Role of imaging
• Imaging Methods
• Anatomy: Larynx (& Hypopharynx)
• SCCa and Pitfalls.
Imaging of the Larynx
• Introduction: Function / Embryology / Role of imaging
• Imaging Methods
• Anatomy: Larynx (& Hypopharynx)
• SCCa and Pitfalls.
Imaging of the Larynx
Preface:
Why consider the larynx and hypopharynx together?
Duplexed structures
Introduction • Function• Embryology• Role of Imaging
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• Larynx:
– Phonation
– Maintenance of the airway
– Protection against aspiration.
Function:
1. Introduction
• Larynx:
– 2 distinct portions separated at laryngeal ventricle:
• Supraglottic larynx: primitive buccopharyngeal anlage*
– Lush lymphatic system
• Glottic and Subglottic larynx: tracheobronchial buds
– Sparse lymphatics.
Embryology:
1. Foregut2. Stomach3. Hindgut4. Midgut5. Pharyngeal gut6. Esophagus7. Tracheobronchial diverticulum8. Buccopharyngeal membrane9. Cloacal membrane10. Stomodeum11. Cloaca12. Gallbladder13. Liver14. Pancreas15. Vitelline duct16. Allantois
http://www.embryo.chronolab.com/digestive.htm
*
1. Introduction
• Larynx:
– Endolaryngeal mucosa is readily visualized:
• Indirect with mirror
• Direct with endoscope
• If inconclusive, direct exam under anesthesia, biopsy
• >95% of malignancies are squamous cell carcinoma (SCCa)
The Role of Imaging:
1. Introduction
• Larynx:
– Pathology often identified relatively early due to:
• Changes in phonation (hoarseness)
• Breathing difficulties (stridor, dyspnea)
• Aspiration
• Hemoptysis
• Odynophagia (painful / difficult swallowing)
• Referred otalgia
The Role of Imaging:
1. Introduction
• Vagus nerve (CN 10): pyriform sinus
• Larynx:
– Radiologist:
• Sub-mucosal / deep soft tissue extension of disease (pre-epiglottic space, paraglottic space, etc)
• Cartilage involvement
• Extralaryngeal extension of disease
• Staging of the neck (nodal status).
The Role of Imaging:
1. Introduction
• Introduction: Function / Embryology / Role of imaging
• Imaging Methods
• Anatomy: Larynx (& Hypopharynx)
• SCCa and Pitfalls.
Imaging of the Larynx
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Imaging • CT• MRI
• Preferred modality (available, fast, higher res)
• Total IV contrast = 105 cc, 2-stage bolus
– 1st bolus: 50 cc at 1.5 cc/sec
– 2nd bolus: 55 cc at 1.5 cc/sec, approx. 130 seconds after start of 1st bolus
– SCAN: total of 160 seconds delay
Contrast-Enhanced CT:
2. Imaging Methods
• Above orbits through clavicles, 2 mm slices
Carina
2. Imaging Methods
Contrast-Enhanced CT:
• Reformats:
– Axial along the plane of the glottis, 1 mm slices.
2. Imaging Methods
Standard AxialGlottic Reformats
Contrast-Enhanced CT:
• Reformats:
– 2mm Coronal and Sagittal (essential).
2. Imaging Methods
Contrast-Enhanced CT:
• Limited application for larynx / hypopharynx
– Usually poor quality images due to motion from breathing, swallowing, secretions
MRI:
2. Imaging Methods
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• Introduction: Function / Embryology / Role of imaging
• Imaging Methods
• Anatomy: Larynx (& Hypopharynx)
• SCCa and Pitfalls.
Imaging of the Larynx
Anatomy • Larynx
• (Hyopharynx)
Anatomy—Larynx:
• Cartilages
• Endolarynx― Supraglottis
― Glottis
― Subglottis
Anatomy—Larynx:
• Cartilages
• Endolarynx― Supraglottis
― Glottis
― Subglottis
Laryngeal Cartilages:
Cricoid
Cricothyroid Ligament
Inf. Horn Thyroid Cart.
Thyroid Cartilage
Arytenoid Cartilage
Corniculate Cartilage
Sup. Horn Thyroid Cart.
Thyrohyoid Membrane
Hyoid Bone
EpiglottisAnterior Posterior
3. Anatomy Larynx / Hypopharynx
• Thyroid Cartilage:– Largest laryngeal cartilage,
shields larynx
– Superior cornua attach to thyrohyoid ligament
– Inferior cornua articulate medially with cricoid cartilage
Laryngeal Cartilages:
Posterior View
3. Anatomy Larynx / Hypopharynx
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• Cricoid Cartilage:– Only complete ring in larynx;
provides structural integrity
– “Signet ring”;
• anterior arch = band
• posterior lamina = signet
– Lower border = junction of larynx and trachea
– Conservative surgical therapy will not be successful if tumor present within the cricoid
Laryngeal Cartilages:
PosteriorAnterior
3. Anatomy Larynx / Hypopharynx
• Arytenoid Cartilage:– Paired pyramidal cartilages
– Sit on top of posterior cricoid cartilage lamina
– Most in supraglottis; vertical height spans the ventricle
– Vocal* and muscular*processes are at level of true vocal cord
– Superior process at false cord
Laryngeal Cartilages:
*
*
Posterior View
3. Anatomy Larynx / Hypopharynx
Laryngeal Cartilages:
3. Anatomy Larynx / Hypopharynx
Hyoid BoneThyroid CartilageArytenoid CartilageCricoid Cartilage
• Cartilages
• Endolarynx― Supraglottis
― Glottis
― Subglottis
3. Anatomy Larynx / Hypopharynx
Anatomy—Larynx:
Larynx
• Supraglottic
• Glottic
• Subglottic
Hyoid Bone
Thyroid Cartilage
Cricoid Cartilage
3. Anatomy Larynx / Hypopharynx
Supraglottic LarynxFalse Vocal Cord
Aryepiglottic Fold
Pre-epiglottic Fat
3. Anatomy Larynx / Hypopharynx
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Glottis
True Vocal Cord
Arytenoid Cartilage
Cricoid
Paraglottic Fat Stripe
Thyroarytenoid Muscle
Anterior Commissure
Posterior Commissure
3. Anatomy Larynx / Hypopharynx
Subglottic Larynx
Thyroid Cartilage
Cricoid
3. Anatomy Larynx / Hypopharynx
• Hyoid bone to inferior cricoid cartilage
• 3 Regions:
– Posterior wall
– Pyriform sinus
– Post-cricoid
3. Anatomy Larynx / Hypopharynx
Anatomy—Hypopharynx:Hypopharynx
• Posterior Wall
• Pyriform Sinus
• Post-Cricoid
Hyoid Bone
Thyroid Cartilage
Cricoid Cartilage
Trachea
Transverse Arytenoid muscle
3. Anatomy Larynx / Hypopharynx
Hypopharynx
• Posterior Wall
• Pyriform Sinus
• Post-Cricoid
Mucosa overlying the posterior confluence of
the aryepiglottic folds
3. Anatomy Larynx / Hypopharynx
Imaging Anatomy
CT of the Larynx and Hypopharynx
Transverse and Oblique Arytenoid Muscles
Supraglottic Larynx
Pyriform Sinus
Posterior Wall
Posterior confluence of the Aryepiglottic
Folds
3. Anatomy Larynx / Hypopharynx
For a review of the axial CT anatomy of the Larynx, please visit us on-line at:www.headandneckrad.com
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• Introduction: Function / Embryology / Role of imaging
• Imaging Methods
• Anatomy: Larynx (& Hypopharynx)
• SCCa and Pitfalls.
Imaging of the Larynx
SCCa & Pitfalls
• Larynx• (Hypopharynx)
Duplexed structures
SCCa Risk Factors:• Smoking• Alcohol ingestion
4. SCCa and Pitfalls
• Tumor extension:
– Superior to Inferior: Transglottic
– Anterior / Lateral: Extralaryngeal
– Posterior: Anterior hypopharyngeal wall
• Cartilage:
– Thyroid cartilage has variable calcification / ossification that can mimic tumor invasion when asymmetric.
– Look for paraglottic fat.
SCCa and Pitfalls: Larynx
4. SCCa and Pitfalls
• Tumor extension:
– Anterior: larynx (thyroarytenoid and cricothyroid tunnels)
– Posterior: pre-vertebral space (invasion = non-surgical)
– Lateral: around posterior thyroid cartilage; >180 involvement of the ICA / CCA = non surgical.
• Distant metastasis
SCCa and Pitfalls: Hypopharynx
4. SCCa and Pitfalls
Supraglottic SCCa:
4. SCCa and Pitfalls
1/2
70-y.o. female with 15-month history of “laryngitis” with
pain and hoarseness.
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Supraglottic SCCa:
2/2
4. SCCa and Pitfalls
Glottic SCCa:60-y.o. male with 5-month
history of hoarseness.
1/2
4. SCCa and Pitfalls
Glottic SCCa:
2/2
4. SCCa and Pitfalls
Subglottic SCCa:59-y.o. male with 5 month history of dysphonia; laryngoscopy showed an exophytic mass just inferior to the anterior Commissure
1/4
Trachea
4. SCCa and Pitfalls
Subglottic SCCa:
2/4
4. SCCa and Pitfalls
Trachea
Subglottic SCCa:
3/4
4. SCCa and Pitfalls
Trachea
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Subglottic SCCa:
4/4
4. SCCa and Pitfalls
Extra-laryngeal SCCa:
1/1
4. SCCa and Pitfalls
Widened Thyro-Arytenoid Tunnel:
Crico-thyroid Tunnel 1/1
Thyro-arytenoid Tunnel
4. SCCa and Pitfalls
SCCa: AE Fold + Transverse Arytenoid:70-y.o. female with dysphagia and dysphonia. 50 pack-
year smoker and moderate alcohol drinker. No otalgia.
1/3
4. SCCa and Pitfalls
2/3
SCCa: AE Fold + Transverse Arytenoid:
4. SCCa and Pitfalls
Normal thyro-arytenoid tunnel
3/3
SCCa: AE Fold + Transverse Arytenoid:
4. SCCa and Pitfalls
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Goals, revisited:
• Describe basic function of larynx
• Define the role of imaging
• Review anatomy
• Identify squamous cell carcinoma (SCCa) & pitfalls.
HeadAndNeckRadwww.headandneckrad.com
• Site dedicated to Head and Neck Radiology education and research• Free access• Features:
• Anatomy• Lectures• Interactive Tutorials• ‘Case of the Month’• Protocols and Imaging Policies• Research• Links• Monthly Newsletter
Eric S Bartlett, MPH MD & Eugene Yu, MD
Thank You!
Eric S. Bartlett, MPH MD
www.HeadAndNeckRad.com
Assistant ProfessorUniversity of Toronto Joint Department of Medical ImagingNeuroradiology, Head and Neck DivisionDepartment of Otolaryngology, Head and Neck SurgeryPrincess Margaret Hospital