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Radiology in Head and Neck
Presenter : Kanato T
INTRODUCTION
 Radiology is a continually evolving
medical specialty
 Since the discovery of x-rays.
 Resulting in the n...
Radiological Investigations
Useful To The ENT Surgeon
 X-rays
 Ultrasound
 CT
 MRI
 PET Scans
 Barium Swallow
 Angi...
X-ray photons
 What Is an X-Ray?
 An x-ray is a discrete bundle of
electromagnetic energy called a photon.
 similar to ...
Image Appearance
 Four basic densities:
1. Air is black or very dark.
2. fat is generally gray and darker than muscle
or ...
Image clarity
Depends on kVp, mA, Time
(sec)
 If radiograph is too light
Increase kVp (increase the
penetrating power or...
Conventional Radiology
 Temporal Bone: Law’s View, Schullars view,
Stenver’s View, Transorbital View,
Submentovertical Vi...
Law’s View (Lateral view of
Mastoid)
 In 1913, Dr Frederik Law described lateral
view of mastoid bone.
 Sagittal plane o...
Structures seen:
 External auditory
canal (EAC)
(superimposed on
internal auditory
canal (IAC)),
 mastoid air cells,
 t...
Schullar’s view
 1906, Dr Arthur Schuller, an Austrian
neuroradiologist, described an oblique view
of mastoid bone.
 X-r...
SCHULLER S VIEW
Clinical applications:
 Extent of pneumatization, sclerotic
mastoid, destruction of intercellular
septa (mastoiditis),
 ...
Stenver’s view:
 In 1917, Dr H. W. Stenver described Stenvers
view of temporal bone
 Long axis of the petrous bone lies ...
Structures seen
 Entire petrous pyramid,
 arcuate eminence,
 internal auditory meatus,
 labyrinth with its vestibule,
...
Stenver’s view:
Towne’s view:
 In 1926, Dr E. B. Town of England described
Towns view.
 This is an anteroposterior view of skull with
30...
Towne’s view
 Structures seen: Both side temporal
bones,
 arcuate eminence and superior
semicircular canal, mastoid antr...
Transorbital view:
 This is an anteroposterior view of skull.
 Orbitomeatal line is at right angles to the
film.
 X-ray...
TRANSEORBITAL PROJECTION:
Submentovertical view:
 Vertex remains near the film and X-ray
beam is projected from the submental
area.
Structures seen:
 External auditory
cannal,
 Middle air cleft. ie.
mastoid cells, middle
ear & eustachian tube
 Interna...
nose and paranasal Sinuses
Water’s view (occipitomental view):
In 1914, Dr C. A. Waters and C. W. Waldron,
two British rad...
Structures seen
 Maxillary (seen
best)
 Frontal and
sphenoid sinuses
 zygoma,
zygomatic arch
 Nasal bones,
frontal pro...
Caldwell view (occipitofrontal
view):
 Eugene W. Caldwell, In 1903, described a
view of the paranasal sinuses that still ...
Structures seen
 Frontal, ethmoid and
maxillary sinuses,
 Frontal process of
zygoma, zygomatic
process of frontal
bone
...
Lateral view
 Lateral side of the skull lies against
the flim and X ray beam is projected
perpendicular from other side.
Structures seen :
 Anterior and posterior extents of
sphenoid, frontal and maxillary
sinuses, sella turcica,
 Ethmoid si...
Common radiologic abnormalities
 Air-fluid levels suggest an acute
process
 Opacification = secretions, polyps, etc.
 T...
Lateral views of nasal bones:
 To see fracture line, depression or elevation of
the fractures segment.
 Lower part of na...
Occlusal view of nasal bone:
 Film is held between
the teeth and X-ray
beam is projected
perpendicular to the
film.
 It ...
Neck, Larynx and Pharynx
Lateral view of neck
 Structure seen: Outline of
base of tongue, vallecula,
 hyoid bone, epiglo...
Clinical applications:
 Radio-opaque foreign bodies of larynx, pharynx and
upper esophagus
 Acute epiglottitis
 Retroph...
Chronic Retropharyngeal abscess
 Secondary to TB
spine(Pott’s spine)
 Erosion of cervical
vertebra
 Treatment with
ATT
FB Cricopharynx with Acute
retropharyngeal abscess
Acute epiglottitis(Thumb sign)
Anteroposterior view of neck:
 It helps in differentiating between a
foreign body of larynx and esophagus
(lateral view i...
 Round radio
opaque object
(Coin) in
Esophagus
 Because the
esophagus is an
AP compressed
tubular structure.
Croup (acute laryngotracheobronchitis)
Steeple Sign
Soft tissue lateral view nasopharynx:
 For soft tissue masses in the nasopharynx,
soft palate, roof and posterior wall of...
Enlarged Adenoids
Submandibular salivary gland:
 Radio-opaque calculus can be seen.
Barium Swallow
 procedure used to examine upper
gastrointestinal tract,which include the
pharynx, esophagus, cardia of st...
CONTRAINDICATION
 Suspected esophageal perforation.
 Tracheo-esophageal fistula
 If strong clincal suspicion of aspirat...
NORMAL-AP /LAT VIEW - SCOUT
AP/LAT VIEW WITH BARIUM
 EFT: Lateral view: Epiglottis (red arrow). Post cricoid
impression (yellow arrows).
 Cricopharyngeous impression (white...
CA ESOPHAGUS
 The stenotic segment is long giving a “rat-
tail” appearance
Barium swallow shows mild dilatation of the
es...
ACHALASIA CARDIA
Bird beak appearance
Sialography
 Radiologic examination of the salivary
glands
 The submandibular and parotid glands
are investigated by thi...
Procedure
 Obtain preliminary radiographs
Any condition that is visibe w/o contrast
Optimum technique obtained
 2-3 mi...
Parotid Radiographs Set-Up
ORTHOPANTOMOGRAPHY
(tomography of the mandible)
 A pantomograph is a
panoramic radiograph
machine.
 It permits
visualiza...
ULTRASOUND
 Ultrasound is sound within a frequency above
the upper limit of normal hearing.
 Ultrasound images are forme...
Transducer(probe)
 Piezoelectric material is used to
produce sound wave
 Usually lead zirconate titanate
 The higher th...
Advantages
 no known harmful effects and no
contraindications.
 High-resolution ultrasound is quick and
accurate;
 Furt...
Ultrasound appearance of
common abnormalities.
Lymph Nodes
 Normal lymphnode may be visualized by usg
in healthy subject,...
 Reactive lymph node.
(a) An oval-shaped,
low-reflective lymph
node with an
echogenic hilum
(arrow)
 (b) Florid colour
D...
 Squamous cell
carcinoma lymph
node metastasis.
 An enlarged low
reflective mass with
an irregular border
(long arrow)
...
Thyroid
 For ultrasound imaging thyroid disorder may be
considered into two groups
 Nodular
 Diffuse
 Major role of us...
Salivary gland disease
 Both the parotid and submandibular glands
are superficial and well sited for ultrasound
examinati...
 Doppler ultrasound measures blood
flow of vessels.
 In Color Doppler flowing blood
appears either red or blue,
 which ...
Applications of Ultrasound
 Differentiating cystic from solid masses
 „Metastatic lymph nodes
 „Tumor invasion of carot...
Computed tomography
 In 1972 Godfrey Hounsfield of Great
Britain invent CT.
 Computed tomography (CT) is
accomplished by...
Computed tomography imaging
 Imaging can be obtained in several
planes.
 In most cases the axial (transaxial)
plane, usu...
Different views of CT pns
 Coronal image
Axial image
Sagittal image
Computed tomography
 Conventional CT scanners have traditionally
operated in a step-and-shoot mode, defined
by data acqui...
Computed tomography
 In general, the basic four densities on
CT images are the same as those in
plain x-rays:
 air is bl...
CT image display
 Hounsfield unit: value of CT number
 Defined by the relationship between the
linear attenuation value ...
CT image display
 The window level is simply the midpoint of the
densities chosen for display
 For imaging of the soft t...
The terminology commonly used to describe
the above mentioned windows includes soft
tissue windows (window width of 250 to...
Contrast CT:
 Intravenous
contrast agents
allow identification
of rim
enhancement in
pathological lymph
nodes and
 incre...
Spiral CT
 Helical or spiral CT scans a volume of
tissue and
 provides better quality images than
the conventional CT.
...
multidetector CT scanners
(MDCTs)
 MDCT can reduce scan time, permit
imaging with thinner collimation, or
both
 Multidet...
CT angiography:
 With intravenous bolus administration
of iodinated contrast material.
 permitted successful imaging of ...
Processing of volumetric data:
 The volumetric data can be processed
to produce
 Multiplanar images: Sagittal and
corona...
3-D image reformatting
 To evaluate bony
Structure
 Like fracture,
tumour,
exostosis,
destructive
lesions etc.
 Helps i...
3-D reconstruction of
ct-angiography
 3- D
reconstruction of
cervical vessels
from CT
volumetric data
set obtained after
...
Optimal slice thickness
 3 mm or 5mm = Neck structure
 2 mm = facial bone, sinunasal cavities
and orbit, laryngohypophar...
Applications of CT,
 Extension of mucosal tumors of suprahyoid neck and metastatic
neck lymph nodes (ring enhancement)
 ...
Magnetic resonance imaging
Principle
 The protons in the nuclei of hydrogen behave
like small spinning bar magnets and al...
Imaging protocols
 The rate of energy loss is designated as the
longitudinal (T1) and transverse (T2)
relaxation times.
...
Imaging protocols
 On T2-weighted images, a long T2
substance (fluid) will appear bright.
 The commonly used pulse seque...
 T1W: Because of high soft tissue
discrimination, T1W images show
exquisite anatomical details.
 „T2W: The pathological ...
MRI head sagittal section T1-
weighted
MRI head axial section T2-
weighted
Gadolinium-enhanced T1W:
 Intravenous gadolinium (used in T1W)
reduces T1 relaxation time and
enhances lesions, which app...
Short-tau inversion recovery:
 The STIR sequence suppresses high
signal intensity from fat (that turn fat
black) and flui...
Different characteristics
 (To quickly identify a
T1WI: fat is white,
CSF and vitreous are
black, and nasal
mucosa is low...
Different characteristics
 To quickly identify a
gadolinium-enhanced
T1WI: nasal mucosa is
white, fat is white, and
CSF a...
ADVANTAGES
 Superior soft tissue contrast resolution
than CT
 No radiation exposure
 Less image quality gets hampered b...
DISADVANTAGES
 Long image acquisition time
 More chance of motion artifacts
 Difficult to stage both primary tumour and...
Applications of MRI
 Tumors of nasopharynx, oropharynx, oral cavity
and tongue
 „Extracapsular spread of tumor from node...
Radionuclide imaging
 Intravenously administered
radiopharmaceuticals
 such as technetium-99m (99mTc)-
pertechnetate con...
Technetium-99m (99mTc)-
pertechnetate scan:
 In salivary gland imaging 99mTc pertechnetate
imaging may be useful for asse...
Thyroid imaging
 Most nuclear medicine imaging uses
various isotopes of iodine (131I and
123I), Technitium-99m pertechnet...
Positron emission tomography
 The positron emission tomography provide a
means of identifying pathology based on
altered ...
 PET image lack anatomical details, which
can be overcome by combining with CT/MR
using software technique
 Depending on...
Positron Emission Tomography
 Used for staging and evaluation of
recurrence for primary head and neck
tumors, detecting d...
Indications of FDG with integrated PET/CT
 SCC patients with
 equivocal nodal disease following
conventional assessment;...
Effect of radiation
 The effects of radiation are usually classified
into two categories, depending on the intensity
of t...
Stochastic effects
 The severity of stochastic effects is
independent of the absorbed dose.
 Under certain exposure cond...
Deterministic effects
 severity of certain effects on human beings
will increase with increasing doses.
 There exists a ...
References
 Adam Grainger & Allison's Diagnostic
Radiology 5th ed
 Basic Radiology LANGE clinical science.
 Scott-Brown...
Radiology in Head and Neck by Kanato T Assumi.
Radiology in Head and Neck by Kanato T Assumi.
Radiology in Head and Neck by Kanato T Assumi.
Radiology in Head and Neck by Kanato T Assumi.
Radiology in Head and Neck by Kanato T Assumi.
Radiology in Head and Neck by Kanato T Assumi.
Radiology in Head and Neck by Kanato T Assumi.
Radiology in Head and Neck by Kanato T Assumi.
Radiology in Head and Neck by Kanato T Assumi.
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Radiology in Head and Neck by Kanato T Assumi.

  1. 1. Radiology in Head and Neck Presenter : Kanato T
  2. 2. INTRODUCTION  Radiology is a continually evolving medical specialty  Since the discovery of x-rays.  Resulting in the numerous imaging modalities  One should bear in mind that most imaging techniques utilizing ionizing radiation, including plain films, computed tomography (CT) and nuclear medicine  Carry with them a lifetime risk of developing cancer.
  3. 3. Radiological Investigations Useful To The ENT Surgeon  X-rays  Ultrasound  CT  MRI  PET Scans  Barium Swallow  Angiography  Dacryocystography  Sialography  Orthopantomogram
  4. 4. X-ray photons  What Is an X-Ray?  An x-ray is a discrete bundle of electromagnetic energy called a photon.  similar to other forms of electromagnetic energy such as light, infrared, ultraviolet, radio waves, or gamma rays.  Having no electrical charge, x-rays are more penetrating than other types of ionizing radiation (such as alpha or beta particles) and are therefore useful for imaging the human body.
  5. 5. Image Appearance  Four basic densities: 1. Air is black or very dark. 2. fat is generally gray and darker than muscle or blood 3. Bone and calcium appear almost white. 4. Items that contain metal (such as prosthetic hips) and contrast agents also appear white.  The contrast agents are barium for gastrointestinal studies and iodine for most intravenously administered agents
  6. 6. Image clarity Depends on kVp, mA, Time (sec)  If radiograph is too light Increase kVp (increase the penetrating power or energy of the x-ray photons) Increase mA (produce more photons) Or to increase time (produce more x-ray photons)  If a radiograph is too dark (overexposed) decrease kVp, mA, or time
  7. 7. Conventional Radiology  Temporal Bone: Law’s View, Schullars view, Stenver’s View, Transorbital View, Submentovertical View.  Nose and Paranasal Sinuses: Water’s View, Caldwell View, Lateral View, Right and Left Oblique Views, Lateral and Occlusal Views of Nasal Bone.  Neck: Lateral View and Anteroposterior Views of Neck, Soft Tissue Lateral View Nasopharynx, Submandibular Salivary Gland
  8. 8. Law’s View (Lateral view of Mastoid)  In 1913, Dr Frederik Law described lateral view of mastoid bone.  Sagittal plane of the skull is parallel to the flim  X ray beam is projected 15 degree cephalocaudal.
  9. 9. Structures seen:  External auditory canal (EAC) (superimposed on internal auditory canal (IAC)),  mastoid air cells,  tegmen,  lateral sinus plate  temporomandibula r joint.
  10. 10. Schullar’s view  1906, Dr Arthur Schuller, an Austrian neuroradiologist, described an oblique view of mastoid bone.  X-ray beam is projected 30° cephalocaudal and prevents superimposition of two sides of mastoid bones.  Structures seen: EAC superimposed on IAC, mastoid air cells, tegmen, lateral sinus plate, condyle of mandible, sinodural angle and atticoantral region (key areas for cholesteatoma and its erosion).
  11. 11. SCHULLER S VIEW
  12. 12. Clinical applications:  Extent of pneumatization, sclerotic mastoid, destruction of intercellular septa (mastoiditis),  location of sinus plate (position of sigmoid sinus) and  tegmen (roof of middle ear and floor of middle cranial fossa),  cholesteatoma and  longitudinal fracture of petrous pyramid.
  13. 13. Stenver’s view:  In 1917, Dr H. W. Stenver described Stenvers view of temporal bone  Long axis of the petrous bone lies parallel to the film.
  14. 14. Structures seen  Entire petrous pyramid,  arcuate eminence,  internal auditory meatus,  labyrinth with its vestibule,  Cochlea  and mastoid antrum
  15. 15. Stenver’s view:
  16. 16. Towne’s view:  In 1926, Dr E. B. Town of England described Towns view.  This is an anteroposterior view of skull with 30° tilt from above and in front.  It shows both petrous pyramids, which can be compared.
  17. 17. Towne’s view  Structures seen: Both side temporal bones,  arcuate eminence and superior semicircular canal, mastoid antrum, IAC, tympanic cavity, cochlea and EAC  Clinical applications: Acoustic neuroma and apical petrositis.
  18. 18. Transorbital view:  This is an anteroposterior view of skull.  Orbitomeatal line is at right angles to the film.  X-ray beam passes through the orbit.  Structures seen: IAC, cochlea, labyrinth and both  petrous pyramids projected through the orbits.  Clinical applications: Acoustic neuroma and petrous pyramid.
  19. 19. TRANSEORBITAL PROJECTION:
  20. 20. Submentovertical view:  Vertex remains near the film and X-ray beam is projected from the submental area.
  21. 21. Structures seen:  External auditory cannal,  Middle air cleft. ie. mastoid cells, middle ear & eustachian tube  Internal auditory canal  sphenoid sinuses
  22. 22. nose and paranasal Sinuses Water’s view (occipitomental view): In 1914, Dr C. A. Waters and C. W. Waldron, two British radiologists, introduced the Waters view.  Nose and chin touch the film and X-ray beam is projected from occipital side.  Open mouth view shows sphenoid sinus. Petrous bones are projected below the maxillary sinuses.  Fractures of right and left nasal bones and their lateral displacement can be seen.
  23. 23. Structures seen  Maxillary (seen best)  Frontal and sphenoid sinuses  zygoma, zygomatic arch  Nasal bones, frontal process of maxilla, superior orbital fissure  and infratemporal fossa.
  24. 24. Caldwell view (occipitofrontal view):  Eugene W. Caldwell, In 1903, described a view of the paranasal sinuses that still bears his name, “the Caldwell view”  Nose and forehead touch the film and X-ray beam is projected 15–20° caudally.  Frontal and ethmoidal sinuses are seen well in this view.
  25. 25. Structures seen  Frontal, ethmoid and maxillary sinuses,  Frontal process of zygoma, zygomatic process of frontal bone  superior margins of orbits, lamina papyracea,  superior orbital fissures.
  26. 26. Lateral view  Lateral side of the skull lies against the flim and X ray beam is projected perpendicular from other side.
  27. 27. Structures seen :  Anterior and posterior extents of sphenoid, frontal and maxillary sinuses, sella turcica,  Ethmoid sinuses, alveolar process, condyle and neck of mandible.
  28. 28. Common radiologic abnormalities  Air-fluid levels suggest an acute process  Opacification = secretions, polyps, etc.  Thickened mucosa : Suggests chronic inflammation
  29. 29. Lateral views of nasal bones:  To see fracture line, depression or elevation of the fractures segment.  Lower part of nasal bones, which is thin, fracture more frequently.  Groove for ethmoidal nerve and vessels may look like fracture line
  30. 30. Occlusal view of nasal bone:  Film is held between the teeth and X-ray beam is projected perpendicular to the film.  It shows fracture line and lateral displacement of the nasal pyramid clearly.
  31. 31. Neck, Larynx and Pharynx Lateral view of neck  Structure seen: Outline of base of tongue, vallecula,  hyoid bone, epiglottis and aryepiglottic folds, arytenoids,  false and true cords with ventricle in between them,  thyroid and cricoid cartilages, subglottic space  and trachea, prevertebral soft tissues, cervical spines  and pretracheal soft tissues and thyroid.
  32. 32. Clinical applications:  Radio-opaque foreign bodies of larynx, pharynx and upper esophagus  Acute epiglottitis  Retropharyngeal abscess:  Position of tracheostomy tube and laryngeal stent  Laryngeal stenosis  Fractures of larynx and hyoid bone and their displacement  Compression of trachea by thyroid or retropharyngeal masses  Caries of cervical spine associated with retropharyngeal abscess  Osteophytes in cervical vertebrae and injuries of spine.
  33. 33. Chronic Retropharyngeal abscess  Secondary to TB spine(Pott’s spine)  Erosion of cervical vertebra  Treatment with ATT
  34. 34. FB Cricopharynx with Acute retropharyngeal abscess
  35. 35. Acute epiglottitis(Thumb sign)
  36. 36. Anteroposterior view of neck:  It helps in differentiating between a foreign body of larynx and esophagus (lateral view is also needed).  It shows compression or displacement of trachea by lateral neck masses such as thyroid swellings.
  37. 37.  Round radio opaque object (Coin) in Esophagus  Because the esophagus is an AP compressed tubular structure.
  38. 38. Croup (acute laryngotracheobronchitis) Steeple Sign
  39. 39. Soft tissue lateral view nasopharynx:  For soft tissue masses in the nasopharynx, soft palate, roof and posterior wall of nasopharynx.  Clinical applications:  Adenoids  Angiofibroma  Antrochoanal polyp  Foreign body nose and tumor.  Choanal atresia
  40. 40. Enlarged Adenoids
  41. 41. Submandibular salivary gland:  Radio-opaque calculus can be seen.
  42. 42. Barium Swallow  procedure used to examine upper gastrointestinal tract,which include the pharynx, esophagus, cardia of stomach.  The contrast used is barium sulfate.  TYPES OF CONTRAST STUDY (i) SINGLE CONTRAST STUDY (ii) DOUBLE CONTRAST STUDY
  43. 43. CONTRAINDICATION  Suspected esophageal perforation.  Tracheo-esophageal fistula  If strong clincal suspicion of aspiration or TEF,then omnipaque swallow (iohexol) advised. XRAY VIEW  SOFT TISSUE NECK,CHEST – AP & LAT
  44. 44. NORMAL-AP /LAT VIEW - SCOUT
  45. 45. AP/LAT VIEW WITH BARIUM
  46. 46.  EFT: Lateral view: Epiglottis (red arrow). Post cricoid impression (yellow arrows).  Cricopharyngeous impression (white arrow).RIGHT: AP-view: Small lateral pharyngeal pouches (arrows)
  47. 47. CA ESOPHAGUS  The stenotic segment is long giving a “rat- tail” appearance Barium swallow shows mild dilatation of the esophagus with irregular stenotic lesion in the lower end of the esophagus “moth eaten appearance
  48. 48. ACHALASIA CARDIA Bird beak appearance
  49. 49. Sialography  Radiologic examination of the salivary glands  The submandibular and parotid glands are investigated by this method  The sublingual gland is usually not evaluated this way because of difficulty in cannulation
  50. 50. Procedure  Obtain preliminary radiographs Any condition that is visibe w/o contrast Optimum technique obtained  2-3 min before procedure give lemon  Contrast media (iohexol) injected into main duct  After procedure suck on lemon to clear contrast  10 min after procedure take radiograph
  51. 51. Parotid Radiographs Set-Up
  52. 52. ORTHOPANTOMOGRAPHY (tomography of the mandible)  A pantomograph is a panoramic radiograph machine.  It permits visualization of entire maxillary and mandibular dentition,  alveolar arches and contiguous structures on a single extraoral film
  53. 53. ULTRASOUND  Ultrasound is sound within a frequency above the upper limit of normal hearing.  Ultrasound images are formed from reflected sound waves.  Sound waves are generated in short bursts by the transducer (or probe)  and the sound energy that is reflected back is collected at the point of origin (the transducer)
  54. 54. Transducer(probe)  Piezoelectric material is used to produce sound wave  Usually lead zirconate titanate  The higher the frequency of the probe the lesser the depth of penetration but gives better spatial resolution.  In neck most of the structures of interest are superficial and required a higher frequency probe of greater than 7.5 MHz
  55. 55. Advantages  no known harmful effects and no contraindications.  High-resolution ultrasound is quick and accurate;  Further, it is relatively inexpensive compared to CT or MRI.  In addition to using echoes to generate images, we can analyze the returning echo frequencies. This Doppler analysis allows identification of moving blood as well as its direction and magnitude
  56. 56. Ultrasound appearance of common abnormalities. Lymph Nodes  Normal lymphnode may be visualized by usg in healthy subject, they are often not seen due to their small size and similar echo- texture with surrounding structure.  When apparent, lymph nodes are reactive, inflammatory or neoplastic.  Retropharyngeal lymph nodes cannot be seen with ultrasound.
  57. 57.  Reactive lymph node. (a) An oval-shaped, low-reflective lymph node with an echogenic hilum (arrow)  (b) Florid colour Doppler flow to the central hilum consistent with a benign reactive lymph node
  58. 58.  Squamous cell carcinoma lymph node metastasis.  An enlarged low reflective mass with an irregular border (long arrow)  carotid artery (short arrow)
  59. 59. Thyroid  For ultrasound imaging thyroid disorder may be considered into two groups  Nodular  Diffuse  Major role of usg in the assessment of disease 1. Detection of focal masses 2. Differentiation of multinodular goiter/hyperplasia from other nodular disease 3. To document the extent of a known thyroid malignancy; 4. Follow up to look for residual, recurrent or metastatic carcinoma; 5. Guidance for FNAC or fine needle aspiration for biopsy.
  60. 60. Salivary gland disease  Both the parotid and submandibular glands are superficial and well sited for ultrasound examination  Ultrasound accurately differentiates salivary gland tumors from other lesions outside gland  Calculi larger than 2mm are detected by usg  And useful in defining location of calculi in relation to the gland parenchyma  It detects the presence and extends of any abscess formation.
  61. 61.  Doppler ultrasound measures blood flow of vessels.  In Color Doppler flowing blood appears either red or blue,  which depends upon the blood direction, towards or away from the transducer.  „Power Doppler: It can demonstrate tissue perfusion.
  62. 62. Applications of Ultrasound  Differentiating cystic from solid masses  „Metastatic lymph nodes  „Tumor invasion of carotid vessels and internal jugular vein.  „Tumors of parotid and submandibular salivary glands  „Salivary duct stones even less than 2 mm  „Detection and drainage of salivary gland abscess under US guidance  „Masses of thyroid and parathyroid glands and US guided fine needle biopsy  „Neck lymphoma.
  63. 63. Computed tomography  In 1972 Godfrey Hounsfield of Great Britain invent CT.  Computed tomography (CT) is accomplished by passing a rotating fan beam of x-rays through the patient and measuring the transmission at thousands of points.  The data are handled by a computer that calculates exactly what the x-ray absorption was at any given spot in the patient.  Compared with plain x-rays, CT uses about 10 to 100 times more radiation
  64. 64. Computed tomography imaging  Imaging can be obtained in several planes.  In most cases the axial (transaxial) plane, usually parallel to the orbitomeatal or infraorbitomeatal plane, is used with the patient lying Supine  In addition, direct coronal imaging and even direct sagittal imaging can be performed.  In fact images can be reformatted in any plane or any angle
  65. 65. Different views of CT pns  Coronal image Axial image Sagittal image
  66. 66. Computed tomography  Conventional CT scanners have traditionally operated in a step-and-shoot mode, defined by data acquisition and patient positioning phases  Helical CT is characterized by continuous patient transport through the gantry while a series of x-ray tube rotations simultaneously acquires volumetric data.  The evolution of multidetector CT scanners (MDCTs) has resulted from the combination of helical scanning with multislice data acquisition.
  67. 67. Computed tomography  In general, the basic four densities on CT images are the same as those in plain x-rays:  air is black,  fat is dark gray,  soft tissue is light gray,  bone or calcium and contrast agents are white
  68. 68. CT image display  Hounsfield unit: value of CT number  Defined by the relationship between the linear attenuation value of the material being scanned and that of water.  Gas = -1000 HU  Water = 0 (zero) HU  Bone = +1000 HU  Fat = - 80 to -100 HU
  69. 69. CT image display  The window level is simply the midpoint of the densities chosen for display  For imaging of the soft tissues of the head and neck, a window level of approximately 40 to 70 HU is usually chosen, at a midpoint approximately equal to the density of muscle  For imaging bony structures such as paranasal sinuses and temporal bone, window levels from 0 to +400 HU and a very wide window width of 2000 to 4000 HU may be chosen
  70. 70. The terminology commonly used to describe the above mentioned windows includes soft tissue windows (window width of 250 to 400 HU) and bone windows (2000 to 4000 HU).  Soft tissue window CT image  Bone window CT image
  71. 71. Contrast CT:  Intravenous contrast agents allow identification of rim enhancement in pathological lymph nodes and  increase the definition of primary tumors.
  72. 72. Spiral CT  Helical or spiral CT scans a volume of tissue and  provides better quality images than the conventional CT.  It covers more than 300 cm tissue during a single breathhold of 30 seconds
  73. 73. multidetector CT scanners (MDCTs)  MDCT can reduce scan time, permit imaging with thinner collimation, or both  Multidetector CT offers the additional advantages of decreased contrast load, reduced respiratory and cardiac motion artifacts, and enhanced multiplanar reconstruction capabilities.
  74. 74. CT angiography:  With intravenous bolus administration of iodinated contrast material.  permitted successful imaging of entire vascular distributions  CT angiography has become an important tool for assessment of the abdominal and iliac arteries and their branches, the thoracic aorta, the pulmonary arteries, and the extra- and intracranial carotid circulation.
  75. 75. Processing of volumetric data:  The volumetric data can be processed to produce  Multiplanar images: Sagittal and coronal  Three-dimensional (3D) images  Virtual endoscopy: Such as laryngoscopy, bronchoscopy and sinuscopy
  76. 76. 3-D image reformatting  To evaluate bony Structure  Like fracture, tumour, exostosis, destructive lesions etc.  Helps immensely in planning reconstruction operation
  77. 77. 3-D reconstruction of ct-angiography  3- D reconstruction of cervical vessels from CT volumetric data set obtained after administration of contrast material  Gives better result than MR angiography
  78. 78. Optimal slice thickness  3 mm or 5mm = Neck structure  2 mm = facial bone, sinunasal cavities and orbit, laryngohypopharyngeal region  0.8 – 1 mm = Temporal bone
  79. 79. Applications of CT,  Extension of mucosal tumors of suprahyoid neck and metastatic neck lymph nodes (ring enhancement)  „Postoperative neck  „Salivary gland tumors and metastatic neck lymph nodes  „Computed tomography sialography  Cervical lymphadenopathy  „Trauma, inflammation and cancer of larynx and laryngopharynx with metastatic neck nodes  „Large or fixed thyroid tumors invading and compressing larynx, laryngopharynx, trachea and mediastinum  „Paranasal sinuses prior to endoscopic sinus surgery, severe nasal polyposis, tumors  „Facial trauma  „Temporal bone and skull base tumors, semicircular canal fistulas, cochlear implants.
  80. 80. Magnetic resonance imaging Principle  The protons in the nuclei of hydrogen behave like small spinning bar magnets and align with a strong external magnetic field.  A radio frequency pulse knocks protons out of alignment, which release small amount of energy while gradually returning to their original position.  This energy is detected by sensitive coils, which are placed around patient.  Hydrogen atoms are abundantly present in body water and MRI can differentiate the water content of various tissues
  81. 81. Imaging protocols  The rate of energy loss is designated as the longitudinal (T1) and transverse (T2) relaxation times.  T1 represents the restoration of the longitudinal magnetization along the axis of the main magnetic field  T2 represents the decay time of the magnetization in the transverse plane.  Substances (e.g.,fluid) that have a long T1 will appear dark on T1-weighted images, whereas those with short T1 (fat) will display high signal intensity.
  82. 82. Imaging protocols  On T2-weighted images, a long T2 substance (fluid) will appear bright.  The commonly used pulse sequences are T1-weighted (T1W), T2-weighted (T2W), gadolinium-enhanced T1W, spin (proton) density, fat-suppressed and gradient echo imaging.
  83. 83.  T1W: Because of high soft tissue discrimination, T1W images show exquisite anatomical details.  „T2W: The pathological lesions increase T2 de-phase times, which produce higher signal than surrounding normal tissue in T2W images.  The combination of T1W and T2W images is good for characterizing fluid containing structures, solid components and hemorrhage.
  84. 84. MRI head sagittal section T1- weighted MRI head axial section T2- weighted
  85. 85. Gadolinium-enhanced T1W:  Intravenous gadolinium (used in T1W) reduces T1 relaxation time and enhances lesions, which appear as high signal intensity areas  Improved delineation of tumor margins relative to the lower signal of muscle, bone, vessel and globe.  Gadolinium enhancement is optimally used with specific fat suppression techniques.
  86. 86. Short-tau inversion recovery:  The STIR sequence suppresses high signal intensity from fat (that turn fat black) and fluid containing structures remain high signal intensity.  In STIR, decreased signal-to-noise ratio degrades the image. Magnetic resonance angiography:  It uses specific sequences  and demonstrates flowing blood.
  87. 87. Different characteristics  (To quickly identify a T1WI: fat is white, CSF and vitreous are black, and nasal mucosa is low signal.)  (To quickly identify a T2WI: CSF, vitreous, and nasal mucosa are white. Fat is low to intermediate in signal.)
  88. 88. Different characteristics  To quickly identify a gadolinium-enhanced T1WI: nasal mucosa is white, fat is white, and CSF and vitreous are black  To quickly identify a STIR image(fat suppresion): fat is almost completely black; CSF, vitreous, and mucosa are white
  89. 89. ADVANTAGES  Superior soft tissue contrast resolution than CT  No radiation exposure  Less image quality gets hampered by the presence of dental fillings
  90. 90. DISADVANTAGES  Long image acquisition time  More chance of motion artifacts  Difficult to stage both primary tumour and neck nodal disease  Higher cost and less availability  Absolute contraindications to MRI include patients with cardiac pacemakers, cochlear implants, and ferromagnetic intracranial aneurysm clips.  Those patients at risk for metallic orbital foreign bodies should be screened with plain films or CT before MRI.
  91. 91. Applications of MRI  Tumors of nasopharynx, oropharynx, oral cavity and tongue  „Extracapsular spread of tumor from nodes  „Perineural spread and extension beyond gland of salivary gland tumors  „Tumors of nose and paranasal sinuses: Distinguish between tumor and obstructed sinus secretions (hydrated fluid,viscous, desiccated);  Perineural spread to anterior cranial fossa, orbit, parapharyngeal space and pterygopalatine fossa and cribriform plate extension  „Lesions of IAC, facial nerve canal, and jugular foramen; acoustic schwannoma  „Skull base tumors
  92. 92. Radionuclide imaging  Intravenously administered radiopharmaceuticals  such as technetium-99m (99mTc)- pertechnetate concentrate selectively in certain tissues and emit gamma radiation detected by a gamma camera.  It provides two-dimensional display of physiological and functional changes in tissue
  93. 93. Technetium-99m (99mTc)- pertechnetate scan:  In salivary gland imaging 99mTc pertechnetate imaging may be useful for assessing salivary gland function in autoimmune and inflammatory disease of the salivary glands.  If obstructed, the degree of obstruction as well as the follow-up of obstruction after treatment can be assessed.  In evaluating neoplasms of the salivary glands the findings of the 99mTcpertechnetate scan are almost pathognomonic of Warthin's tumor and oncocytoma.
  94. 94. Thyroid imaging  Most nuclear medicine imaging uses various isotopes of iodine (131I and 123I), Technitium-99m pertechnetate to determine thyroid function, identify hot or cold nodules, or access extent of thyroid masses and tumors.  1- 4 % of hot nodules – malignant  Upto 25 % of cold nodule – malignant
  95. 95. Positron emission tomography  The positron emission tomography provide a means of identifying pathology based on altered tissue metabolism.  Imagining technique relies on a radioactive molecule(radiotracer) that decay with positron emission.  The radiotracer is given intravenously to the patient and is taken into cells.  Malignant cell trap more radiotracer compare to non malignant cells.  The local radiotracer concentration can be measured.
  96. 96.  PET image lack anatomical details, which can be overcome by combining with CT/MR using software technique  Depending on the radiotracer used different aspects of tissue metabolism can be measured.  An analogue of glucose, 2-[18F] fluoro-2- deoxy-D-glucose (FDG) which reflects glucose metabolism is commonly use.
  97. 97. Positron Emission Tomography  Used for staging and evaluation of recurrence for primary head and neck tumors, detecting distant lymph node, soft-tissue and skeletal metastases  More accurate than CT or MRI in detecting residual or recurrent nodes  Highly reliable after 3 – 4 months of end of treatment.
  98. 98. Indications of FDG with integrated PET/CT  SCC patients with  equivocal nodal disease following conventional assessment; -suspicion of recurrent/residual disease.  Patients with occult primary tumors.  Post-treatment papillary and follicular thyroid cancer patients with elevated thyroglobulin and negative 131-I scan.  Patients with clinical suspicion of more disease than conventional assessment demonstrates.  Patients where resectability is in doubt.
  99. 99. Effect of radiation  The effects of radiation are usually classified into two categories, depending on the intensity of the radiation and the time period of exposure.  These electrons may damage DNA molecules directly or produce free radicals that can chemically damage genetic material; either effect may result in cell death or mutation  These categories are referred to as 1. stochastic effects 2. deterministic effects
  100. 100. Stochastic effects  The severity of stochastic effects is independent of the absorbed dose.  Under certain exposure conditions, the effects may or may not occur.  There is no threshold and the probability of having the effects is proportional to the dose absorbed.  Example: radiation induced cancer, genetic effect
  101. 101. Deterministic effects  severity of certain effects on human beings will increase with increasing doses.  There exists a certain level, the "threshold", below which the effect will be absent.  This kind of effects is called "deterministic effects“  Example: cataract, erythema, infertility etc.
  102. 102. References  Adam Grainger & Allison's Diagnostic Radiology 5th ed  Basic Radiology LANGE clinical science.  Scott-Brown’s Otorhinolaryngology, Head and Neck Surgery 7th edition.  Surgery of ear Glasscock Shambaugh 6th edition.  Mohan Bansal Disease of Ear, Nose and Throat.  Head and Neck Imaging, Peter M. Som  Internet

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