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Dr Mohamed El Safwany, MD.

Intended Learning Outcome

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The student should be able to recognize technological principles of radiographic imaging of the skull.

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TECHNICAL ASPECTS

Sitting erect positions are preferred to exclude any air-fluid levels within the cranial cavities or sinuses.

Patient comfort and skull immobilization are necessary.

Exposure factors range between 75 kVp and 85 kVp. A small focus is to be used with short times and

high mA.

A high lattice grid (40 lines/inch) must be used.

Good collimation (Narrow cone for small parts) and non-repeats helps

in minimizing the radiation exposure to the patient.

A contact shield should be used over the neck and chest to reduce the exposure to the thyroid and

female breast in the AP projection.

PA Skull (0 Occipital-frontal) projection B

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For frontal bone #s and neoplastic processes of the cranium, Paget’s disease, orbits (obscured by petrous temporals), I.A.M, frontal and ethmoidal sinuses, dorsum sellae.

Patient nose and forehead against the couch center, neck flexed so that OML is 90 to the couch, MSP 90 to couch center, head not rotated, EAMS equidistant from the couch top.

Film: HD 24x30 cm

CP: Exits the glabella

CR: 0 (that is 90) to film center

NB/ AP is not recommended as it produces 200 times eyes absorbed dose

produced in the PA position.

PA Axial Skull (Caldwell projection for

sinuses ) B

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Good for sinuses (frontal and anterior ethmoidal sinuses). Also shows other inflammatory conditions (secondary osteomyelitis, sinus polyps).

Patient’s nose and forehead against film, neck extended so that OML is 15 from the horizontalFilm: HD 18x24 cmCP: Naison (to occiput to exit at level of lower orbital margins).

CR: 90 horizontal to film center (or 15 caudal with OML 90 to the

film).

AP Axial (Towne’s projection) B

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For occipital bone, cranial #s, neoplasms, and Paget’s disease. Also for AP dorsum sellae, and advanced pathology of the temporal bone (advanced acoustic neuroma), anterior clinoids, foramen magnum, mastoids, foramen magnum.

Patient supine, or in erect AP sitting, chin is depressed (OML 90 to film), no rotation of the head

Film: HD 24x30 cm

CP: 6 cm above the glabella (2 cm superior to level of EAMs).

CR: 30 caudal (30 caudal for the

posterior clinoids).

AP Axial (Towne’s projection – for mandible) B

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For #s, neoplastic or inflammatory processes of the condyloid processes of the mandible.

Same position as for Towne AP (OML 90 to couch top.

Film: HD 18x24 cm

CP: Glabella (midway between EAMs and angles of the mandible). A CP at one inch anterior to level of TMJs will show TMJs.

CR: 35- 40 caudal.

Lateral Skull (general) B

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Same indication as for PA (0). A horizontal beam is used for trauma cases

Patient in a semiprone (Sim’s position), recumbent or erect sitting, head in a true lateral (required side close to the film), MSP parallel to couch, IPL 90 to couch top.

Film: HD 18x24 cmCP: 5 cm superior to EAM .CR: 90 to film center .

Lateral Skull (for lateral Sella Turcica) B

To show evidence of pituitary adenomas.

Same position as for the lateral skull (as in Sim’s position), IOML 90 to couch top.

Film: HD 18x24 cm

CP: 2 cm anterior and 2 cm superior to EAM.

CR: 90 to film center

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Lateral Skull (for nasal bones) B

For nasal bone fractures.

Head in true lateral (same position as for lateral skull as in Sim’s position) or erect, chin adjusted so that both IPL and IOML are 90 to couch top.

Film: HD 18x24 cm

CP: 1.25 cm inferior to naison

CR: 90 to film center

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Lateral Skull (for sinuses)

B

For inflammatory conditions: Secondary osteomyelitis, sinusitis, and sinus polyps (good for sphenoid, frontal, ethmoid, and maxillary sinuses).

Patient erect sitting, head in true lateral (IPL 90 to film)

Film: HD 18x24 cm

CP: Midway between outer canthus and EAMCR: 90 horizontal to film center

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Lateral 25 - 30 (Axiolateral) (for mandible) B

For #s, neoplastic, or for inflammatory processes of the mandible (both sides are done for comparison) .

Head in true lateral with MSP parallel to the film, side of interest placed against the film, mouth closed, head then rotated in oblique 30 (for the body), 45 (for mentum), and 10 - 15 for a (general survey).

Film: HD 18x24 cmCP: Mandibular region of interest (body, ramus, ….).

CR: 25 cephalic.

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Lateral 15 (Modified Law for TMJs) S

For advanced bony pathology of the mastoid process.

Patient prone or erect, head in lateral, IPL 90 to film, face ( and MSP) then rotated 15 toward the film. Closed and opened mouth.

Film: HD 18x24 cm

CP: 4 cm superior to upside EAM

CR: 15 caudal to pass through the downside TMJ.

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Axiolateral (Schüller for mastoids) S

For advanced bony pathology of the mastoid air cells.

Patient prone or erect, head in the true lateral, IPL 90 to film, MSP parallel to the film.

Film: HD 18x24 cm

CP: downside mastoid tip (4 cm superior, 4 cm posterior to

upside EAM).

CR: 25 - 30 caudal.

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Axiolateral Oblique (Modified Law for mastoids) B

For advanced pathology of mastoids.

Patient prone or erect, each auricle taped forward, head in lateral, then rotated 15 oblique toward the film, IPL 90 to couch, side of interest down.

Film: HD 18x24 cm

CP: Exit downside mastoid tip (1 inch posterior, 2.5 cm posterior, 2.5

cm superior to upside EAM).

CR: 15 caudal

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Submentovertex (SMV) S

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For base of the skull (Basilar view), occipital bone, mandible, foramen ovale and foramen magnum, TMJs, orbits, zygomatic arches, sphenoidal, maxillary sinuses and mastoid processes.

Patient supine or erect sitting, chin raised, neck hyperextended till IOML is parallel to film, MSP 90 to couch top. A pillow under patient’s back allows for sufficient extension.

Film: HD 24x30 cm.

CP: Midway between angles of mandible (2 cm anterior to level of

EAMs).

CR: 90 to IOML.

Submentovertex (SMV) (for mandible) S

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For #s, neoplastic, or inflammatory processes of the mandible.

Patient supine or erect sitting, chin raised, neck hyperextended till IOML is parallel to film, MSP 90 to couch top. A pillow under patient’s back allows for sufficient extension.

Film: HD 18x24 cm

CP: Midway between angles of mandible (4 cm inferior to

mandibular symphysis).

CR: 90 to IOML.

ORTHOPANTOMOGRAPHY (tomography of the mandible) S

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For #s of the mandible and TM joint.

Tube and film attached at starting position, chin rest raised to same level as patient’s chin, chin rested on a sterile bite block, patient as close as possible to the tube stand, chin adjusted until IOML is parallel with the floor, occlusal plane declines 10 from posterior to anterior, patient’s lips placed together, tongue on roof of the mouth.

Film: HD 23x30 cm, or curved non-grid cassetteCP: Fixed CR and FFD.

Parieto-orbital (Rhese View) for optic

foramina S

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For bony abnormalities of the optic foramen. Both sides must be done for comparison. Patient prone or erect, chin, cheek, and nose against couch, head adjusted so that the MSP makes 53 with the couch top, the acanthiomeatal line AML makes 90 to the film, a long narrow cone should be used. Film: HD 18x24 cmCP: Downside orbit (7 cm above and 7 cm behind the up EAM).

CR: 90 to IR

Parietoacanthial (OM) (Waters View for

sinuses ) B

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Best for maxillary and frontal sinuses and nasal fossae. Also shows

other inflammatory conditions (secondary ostemyelitis, and sinus

polyps).

Patient erect, neck extended, chin and nose against couch, head

adjusted till MML is 90 to the film.

Film: HD 18x24 cm

CP: At level of lower border of the orbits to exit at the acanthion.

CR: 90 horizontal to film center

Parietoacanthial (OM) (Open-Mouth Waters

for sinuses ) S

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Same as for Waters..

Same position as for Waters view, but with open mouth (patient drops his jaw without moving the head).

Film: HD 18x24 cm.

CP: At level of lower border of the orbits to exit at the acanthion.

CR: 90 horizontal to film center

Assignment

Two students will be selected for assignment

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Suggested Readings

Clark’s Radiographic technology

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QuestionDescribe

radiographic principles of SKULL PA radiogram?

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Thank You

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