Neuroradiology - Head And Neck

Front 1

Head and Neck Part II

Front 2

Masticator Space

Front 3

Masticator Space Lesions DDx - Most common

Back 3

1. Odontogenic abcess 2. Sarcoma 3. NHL 4. SCC from oropharynx (retromolar trigone) 5. Rhadomyosarcoma in pediatric population 6. Accessory parotid gland 7. Benign Masseteric Hypertrophy

Front 4

Masticator Space Lesions DDX - by category

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1. Pseudotomor a. Accessory parotid gland b. Benign Masseteric hypertrophy c. V3 denervation atrophy 2. Congenital d. Hemangioma e. Lymphangioma 3. Inflammatory f. Odontogenic abscess g. Mandibular osteomyelitis 4. Benign tumor h. Osteoblastoma i. Leiomyoma j. Neural sheath tumor 5. Malignant Tumor k. Sarcoma i. soft tissue ii. chondrosarcoma iii. osteosarcoma l. Malignant schwannoma m. NHL n. SCC from retromolar trigone of oropharynx o. Mandibular mets p. Rhabdomyosarcoma in peds

Front 5

What is a complication of MS infection? In which direction does infection spread?

Back 5

1. Skull base osteomyelitis (destruction of pterygoid wing) 2. Upward via least resistance

Front 6

What makes malignant tumor from MS unresectable?

Back 6

1. Invasion of skull base 2. Check for suprazygomatic MS spread to adjust radiation ports!!

Front 7

Which way is the PPF (prestyloid paraphyngeal fat) displaced in Masticator space lesions?

Back 7

1. Posteriomedially

Front 8

If tumor in MS, what cranial nerve should be inspected for perineural spread? What is the route?

Back 8

1. V3 2. 2. via foramen ovale (medial pterygoid fascia inserts medial to FO)

Front 9

Which motor nerve supplies muscles of mastication?

Back 9

1. Masticator nerve (motor branch) of V3

Front 10

What are the masticator muscles?

Back 10

1. Masseter 2. Medial pterygoid 3. Lateral pterygoid 4. Temporalis

Front 11

What are the two nerves that enter the masticator space?

Back 11

1. Masticator nerve (to all masticator muscles) 2. Inferior alveolar nerve

Front 12

What are the routes of infection/malignancy into the skull base?

Back 12

1. Muscle attachments to skull base (infection goes up b/c firm attachment of periosteum to inferior mandible 2. V3 through foramen ovale à Meckels cave à root entry zone in lateral pons

Front 13

What 3 clinical features suggest involvement of V3 by tumor?

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1. Atrophy of masseter 2. Mandibular pain 3. Serous otitis media (due to tensor palatini dysfunction due to V3 branch involvement causig Eustachian tube malfunction)

Front 14

What is the temporal fossa?

Back 14

1. The suprazygomatic MS

Front 15

What is the infratemporal fossa? Aka?

Back 15

1. Between PPF and zygomatic arch at level of nasopharynx 2. Nasopharyngeal MS

Front 16

What borders the MS?

Back 16

1. Posteromedially = masticator space 2. Anteriorly - buccal space 3. Posteriorly - parotid space 4. What is in the buccal space? 5. Buccinator muscle 6. Parotid duct 7. Facial artery and vein 8. Buccal fat pad

Front 17

What is a pitfall in perineural spread imaging for V3?

Back 17

1. Not imaging along its entire course i.e. 2. Inferior alveolar nerve and masticator nerve 3. Mandibular foramen 4. Foramen ovale 5. Meckels cave 6. root entry zone along lateral pons

Front 18

What is the significance of MS infection involving mandible (osteomyelitis)? Tumor?

Back 18

1. Longer antibiotics 2. More likely perineural spread along IAN or V3 main trunk

Front 19

Why is CT the initial study of choice in evaluating patients with suspected infection of MS?

Back 19

1. Identify duct stone 2. R/o mandibular osteomyelitis

Front 20

Name 3 pseudomasses of MS?

Back 20

1. Accessory parotid gland 2. Benign masseteric hypertrophy 3. Cranial nerve V3 motor atrophy

Front 21

Benign Masseteric hypertrophy - most common cause, pitfall, most characteristic appearance? Imaging recc if not pathognomonic?

Back 21

1. Bruxism (molar grinding) 2. Unilateral mass with infiltrating margins - tumor/infection! 3. Well defined bilateral hypertrophy or if accompanied by pterygoid/temporalis hypertrophy and atrophy with hx of bruxism 4. Close radiologic f/u to r/o tumor

Front 22

What muscles does the motor root of V3 innervate?

Back 22

1. Masticator muscles 2. Anterior belly of digastric 3. Mylohyoid muscle 4. Tensor veli palatini, tensor tympani

Front 23

What are imaging signs of V3 denervation atrophy? How long after injury?

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1. Fatty infiltration 2. Volume reduction 3. 6 weeks

Front 24

What is initial symptom in odontogenic Abscess?

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1. Trismus

Front 25

Odontogenic abscess with lumpy jaw - what should you think?

Back 25

1. Actinomycosis

Front 26

Check list for imaging of inflammatory disease of masticator space?

Back 26

1. Parotid duct calculus present? - make sure CT performed 2. Osteomyelitis present - mandible OR skull base - longer abx 3. Any other spaces involved - need separate drain 4. Is suprazygomatic space involved?

Front 27

Sarcoma - where does chondrosarcoma arise from? Osteosarcoma?

Back 27

1. Chondrosarcoma - from TMJ 2. Any along mandible

Front 28

Tubular Mass?

Back 28

1. Malignant schwannoma along IAN, V3 2. Perineural spread

Front 29

W hat key features suggests malignancy?

Back 29

1. Infiltrating border

Front 30

What secondary feature of MS mass suggests NHL?

Back 30

1. Other cervical nodes, extranodal lymphatic disease (i.e. waldeyers ring)

Front 31

What is most typical for SCC of MS?

Back 31

1. Prior hx of treatment of oral cavity or oropharyngeal SCC 2. Look for perineural spread by IAN

Front 32

ORBIT

Front 33

RETRO-OCULAR MASS (Intraconal)

Back 33

1. Hemangioma - - enhance - phleboliths seen in 10% 2. Optic nerve glioma 3. Optic nerve meningioma 4. Angioma 5. Lymphangioma 6. AVM

Front 34

Extraconal-intraorbital Lesion - DDx

Back 34

1. Benign Tumor a. 1. Dermoid Cyst b. Teratoma c. Capillary Hemangioma d. Lymphangioma e. Plexiform neurofibroma f. Inflammatory orbital pseuydotumor g. Histiocytosis X (usually arises from bone) 2. Malignant Tumor a. Lymphoma/Leukemia b. Metastasis c. Rhabdomyosarcoma

Front 35

Masticator Space Lesions DDx Most common

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1.

Front 36

Masticator Space Lesions DDX by category

Back 36

1.

Front 37

What is a complication of MS infection? In which direction does infection spread?

Back 37

1.

Front 38

What makes malignant tumor from MS unresectable?

Back 38

1.

Front 39

Which way is the PPF (prestyloid paraphyngeal fat) displaced in Masticator space lesions?

Back 39

1.

Front 40

If tumor in MS, what cranial nerve should be inspected for perineural spread? What is the route?

Back 40

1.