head and neck radiology Flashcards
- Head and neck imaging techniques
- US (glands, vessels)
- X-rays (paranasal sinuses , trauma)
- CT (carcinoma, head and neck spaces )
- MRI ( ST, TM joint, orbits, carcinoma of glands, acoustic neuroma )
o Introduction:
- Imaging procedures are used according to the anatomical region/subregion being examined and the clinical question being investigated.
o Ultrasound:
- Basic imaging modality
- Thyroid gland, parathyroid gland, nodes, salivary glands, big vessels and carcinoma - Also tongue and floor of mouth
o X-ray:
- For paranasal sinuses – acute and chronical inflammatory disease
- Trauma to the facial bones
- Asses the trachea (displacement, compression)
o CT:
- In areas when usg is not enough
- bone is assessed by obtaining high-resolution slices
- Usually contrast medium is applied by the intravenous route to assess soft tissue - Also good obtain image of salivary stones
- retromandibular, retropharyngeal and parapharyngeal space, larynx, paranasal sinuses and carcinoma of head and neck
o MRI:
- Similar indications like CT
- Best method to image soft tissues of the head and neck
- Method of choice to demonstrate bone and soft tissue tumors
- + TM joint, orbits, salivary glad carcinoma
o Other: contrast examinations – sialography and fistulography, also core-cut biopsy
- Diseases of thyroid and parathyroid glands
- ultrasound
- normal thyroid
- hashimoto thyroiditis
- graves disease
- cysts
- calcifications
- adenoma
o Thyroid: Ultrasound: - cheap, quick and no radiation - examine by linear probe - it lies from C5-Th1 vertebrae - normal thyroid gland is homogenous and it has high echogenity - Volume > 3 mm - 10-15 ml for females - 12-18 ml for males o Struma: - Struma diffusa (thyroid gland Is bigger an it has homogenous echogenity) - Struma nodoa (thyroid gland Is bigger and has heteregenous echogenity and nodus (hyper, hypo, anecho) o Inflammatory diseases: Acute inflammatory disease: - Gland is bigger - Heterogenous echogenity - Expressive pain - Complication is abscess o Hashimoto thyroiditis: - Atrophic/hypertrophic - Lower echogenity - Irregular walls o Graves disease: - Enlarged thyroid gland - Heterogenous echogenity - Hypervascularization o Subacute thyroiditis: - Enlarged thyroid gland - Heterogenous echogenity o Riedel thyroiditis: - Chronical inflammatory disease - it looks like Ca o Cyst: - Anechogenic with posterior acoustic enhancement o Calcification: - Hyperechogenic with posterior shadowing o Adenoma: - Hypoechogenic or iso - Hypervascularization o Carcinoma: - Heterogenous unbounded mass with cyst or calcification
o Parathyroid gland:
- Ultrasound – high frequency probe (5-10Mhz)
- MRI
- 2 pairs – inferior and superior
- Oval or bean shaped
- Superior parathyroid glands: located at the posterior aspect of the middle-third of the thyroid gland
- Inferior para: located lateral to the inferior pole of the thyroid gland - USG = homogenous hypoechoic
o Parathyroid adenoma:
- Oval hypoechoic mass on the posterior site of the thyroid gland
- diseases of paranasal sinuses, temporal bone and orbits
- acoustic neuroma : from vestibulocochlear nerve ( hyperintense MRI T1 +gd)postcontrast enhancement
Try to remember some of these ( a never-ending list of lesions in the compendium, too much)
- orbit
capillary hemangioma: (hyperintense on T2 +T1C+)
optic neuritis: ( common cause MS) hyperintense on T2
orbital tumor : CT-hyperdense, T1W-isointense
choroidal melanoma : MRI- T1 melanin hyperintese, T2 melanin hypointense (modality of choice). CT- contrast E-hyperdense
Lymphoma: CT-hyperdense, MRI-hypointense
o Introduction: Paranasal sinuses are arranged in a pair-wise manner. They are cavities of the visceral cranium, grouped around the nasal cavity.
o Diseases of paranasal sinuses:
- X-ray and CT
- Inflammatory disease – acute or chronic (thickened mucous membrane and in acute also fluid)
- Fractures and bleeding
- Carcinoma (destructed bones)
o Inflammation of paranasal sinuses:
- The most common condition
- associated with obstruction of nasal breathing, secretion, sensation of pressure - Radiography: parieteal and/or polypoid shadows (mucosal swellings) or air-fluid levels. CT provides anatomical variations that constrict the ostia and permits significantly better demarcation of changes in mucosa
o Tumors of paranasal sinuses:
- usually squamous cell carcinoma
- Contrast-assisted CT shows the extent of tumor and bone destruction
- Contrast-enhanced MRI is able to distinguish mucosal swelling from tumor itssue, and shows invasion of the skull base
o Osteomas:
- Harmless incidental findings in frontal sinuses or ethmoid cells
o Fibrous dysplasia:
- looks like frosted glass on radiopgraphs and CT. It absorbs contrast medium on MRI in active stage
o Diseases of temporal bone:
- CT, MRI
- Inflammatory diseases (fluid, thick mucosa and also lower pneumatisation) - Fractures
- Tumors
- Cholesteatoma (expension in the middle ear or masteoid process. On MRI it is hypersignal) - Osteoma, neurinoma
o Diseases of orbit:
- USG, CT, MRI
- Corpus alienum – CT
- Fracutres – CT
- Tumor (melanoma, lymphoma, carcinoma) – USG, CT, MRI
- neck lymphadenopathy
- non-lymphatic neck and facial expansions
- diseases of larynx and pharynx
remember diff between normal and mts lymph nodes
LN - USG
normal: oval shape- hypoechoic with hyperechoic hilum + central vascularisation)
LN MTS - USG
- round shape - irregular walls - heterogenous echogenicity - peripheral vascularization
( NO hyperechoic hilum)
o Neck lymphadenopathy:
- USG :
- Enlarges nodes because of: lymphadenitis, MTS, lymphoma
o Lymphadenitis:
- Oval hypoechoic nodes
- Hyperechoic center
- Hypervascularized in the center
- Complication – abscess
o Abscess in nodes:
- Hypoechoic or anechoic without vascularization
o Metastasis:
- Round shape
- Peripheral vascularization
- Heterogeneous
o Lymphoma:
- Conglomerate
- Round shaped
- Hypervascularized heterogeneous nodes
o Non-lymphatic neck expansions: - USG, CT, MRI - Cervical cyst – middle, lateral - Glomus tumor o Middle cervical cyst: - Solitary or multiple - In USG they are anechoic with posterior acoustic enhancement - No vascularization o Lateral cervical cyst: - Heterogenous echogenity - No vascularization
o Glomus tumor:
- Typically by the carotic bifurcation
- Hypoechoic, hypervascularized
o Facial expansions:
- X-ray, CT, MRI
- Malignant or benign
- Bening = ameloblastoma (x-ray = cystic mass with septa), odontoma, fibroma - Malignant = maxillar/mandibular carcinoma
o Larynx:
- MRI, CT
- Trauma – hematoma and deformation of larynx, soft tissue edema
- Dislocation and fracture of cartilages – emphysema
- Laryngitis – common abscess in soft tissue
- Carcinoma larynges – supraglottic, glottis, subglottic (45% of all head and neck tumors) - Carcinoid – limited expansion
o Pharynx:
- Double contrast examination (asymmetry, stasis), CT and MRI
- Dysphagia (inability to move food properly from the mouth to the stomach) - Aspiration (most severe form of a swallowing disorder and can result in aspiration pneumonia, chronic lung disease or choking)
- Zenker´s diverticulum (on the border of pharynx and esophagus)
- Retropharyngeal abscess
- Carcinoma
- salivary glands diseases
o Introduction:
- Numerous (500-1000) tiny salivary glands are present in the mucous membranes of the upper aerodigestive tract and are demonstrable only in the presence of disease - Only the paired major salivary glands (parotid, submandibular and sublingual) are directly seen on radiological images
o Location:
- Parotid (largest extending from external auditory canal to the angle of the jaw) - Submandibular (lies mainly below the mylohyoid muscles, but enter the oral cavity in the sublingual aspect close to the frenulum
- Sublingual (lies on floor of the mouth and enter oral cavity with several ducts o Imaging procedures:
- USG and MRI
- MR sialography (non-invasive) has replaced conventional invasive sialography - Calculi not visualized by USG are imaged best by CT
o Inflammation:
- common and accompanied by swelling and pain
- Viral pathogens (mumps) in children
- Bacterial in adults (because of impaired SG function)
- USG only used in patients not responding to therapy
- Sjogrens (autoantibodies associated with interstitial lymphocytic invasion, atrophy and dryness of mouth)
- Sjogrens (multiple small extensions of ducts seens as round hyperintensites o Sialolithiasis:
- 90% in submandibular
- Causes ductectasia
- Painful swelling of the gland
- Clearly seen on USG
- Calculi not observed on USG, can be observed on CT
- Larger calculi may even be found on MRI
- Location of stones determine correct procedure of treatment
- Hypointense stones, large gland, dilated duct
o Tumors:
- 3% of neoplasms of head and neck
- Benign parotid tumors (60-80%)
- Pleomorphic adenomas (75%) occasionally develops into malignancy
- USG
- MRI if doctor suspect part of the tumor to be in the deep parapharyngeal aspect - Size, morphology, position in relation to vessels and facial nerve are significant - Painful tumors with facial nerve paresis, blurred contours or enrlages lymph nodes should raise suspicion of malignant disease
- facial trauma
o Introduction:
- X-ray and CT
- X-ray projections: PA, L, Waters projection and lateral projection with focus on nose bones - Direct x-ray signs: defect cortices, absence of bone fragment, asymmetry of facial bones - Indirect x-ray signs: Fluid in paranasal sinuses, air – pneumoorbita and soft tissue edema o Catergories:
1. Fractures of middle facial area (localized central):
- Fracture of nose bones
- Sagittal maxillary fractures
- Fracture of NOE complex (olfactory labyrinth, lacrimal apparatus and nasofrontal ductus) - Le Fort factures (1 – lower subzygomatic, 2 – upper subzygomatic or pyramidal, 3 – suprazygomatic)
2. Fractures of the middle facial area (localized lateral)
- Zygomatic complex fractures
- Isolated fracture of acus zygomaticus
3. Orbital fractures
o Le Fort II:
- May result from a blow to the lower or mid maxilla
- Usually involve the inferior orbital rim
- Pyramidal shape extending from nasal bridge through frontal processes of maxilla o Le fort III:
- Transverse
- Known as craniofacial dissociation involving the zygomatic arch
- Start at nasofrontal and frontomaxillary sutures extending posteriorly along medial wall of the orbit through nasolacrimal groove and ethmoid bones
- The thick sphenoid bone prevents continuation of the fracture into the optic canal - This type of fracture predisposed to CSF rhinorrhea more commonly than other types
