NEW-SKULL头颅影像学.ppt

1,COURSE RAD331,The Skull,Layout and design by A Musa, Department of Radiological Sciences, Faculty of Applied Medical Sciences, King Saud University, Riyadh, Copyright 2003 A Musa,1,2,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,3,For frontal bone, #s and neoplastic processes of the cranium, Pagets 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 (or PA Axial) Skull (for mandible ) B,4,Best for the body of mandible for #s, inflammatory and neoplastic processes. PA axial well shows rami and elongated view of condyloid process. Patient positioned as or PA (0), chin tucked so that OML is 90 to film, MSP 90 to the couch top, head not rotated. Film: HD 24x30 cm CR: PA: 90 to film center (CP to junction of the lips). PA axial: 20- 25 cephalic (CP to the acanthion),PA Axial Skull (15 Caldwell) projection for facial bones B,5,For #s, neoplastic processes of frontal, parietal and facial bones, and for cranium and an unobstructed view of the orbits, I.A.M, frontal and ethmoidal sinuses, clinoids, dorsum sellae, zygomatic bones. Same position as for PA Film: HD 24x30 cm CP: Exits the naison. CR: 15 caudal (for showing the petrous ridges). 25 - 30 gives better view of orbital rim and floors and superior orbital fissure.,PA Axial Skull (Caldwell projection for sinuses ) B,6,Good for sinuses (frontal and anterior ethmoidal sinuses). Also shows other inflammatory conditions (secondary osteomyelitis, sinus polyps). Patients nose and forehead against film, neck extended so that OML is 15 from the horizontal Film: HD 18x24 cm CP: 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 (Townes projection for AP Sella Turcica) B,9,Detects pituitary adenomas in the sella turcica. Also shows dorsum sellae, posterior clinoids, occipital bone, petrous pyramids, the foramen magnum, mastoids air cells, and zygomatic arches Same position as for Towne (AP) Film: HD 18x24 cm CP: 4 cm above superciliary arch CR: 37 caudal (for the dorsum sellae and the posterior clinoids), 30 (for anterior clinoids),AP Axial (Townes projection for mandible) B,10,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 to RBL .,Lateral Skull (general) B,11,Same indication as for PA (0). A horizontal beam is used for trauma cases to show air-fluid levels in the sphenoid sinus (a sign of # in the base of skull with internal bleeding) with CR 25-30 caudad Clark! Patient in a semiprone (Sims 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 cm CP: 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 Sims 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 NB/ (1) Both laterals may be done with stress on macroradiography. (2) A long narrow (slender) cone should be used.,12,Lateral Skull (for lateral facial bones) B,For fractures, neoplastic or inflammatory processes of facial bones, orbits, and the mandible. Head in true lateral (same position as for lateral skull as in Sims position), chin adjusted so that both IPL and IOML are 90 to couch top Film: HD 18x24 cm CP: Zygoma (midway between the outer canthus and EAM) CR: 90 to film center,13,Lateral Skull (for nasal bones) B,For nasal bone fractures. Head in true lateral (same position as for lateral skull as in Sims 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 NB/ A long narrow cone should be used.,14,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 EAM CR: 90 horizontal to film center,15,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 cm CP: Mandibular region of interest (body, ramus, .). CR: 25 cephalic.,16,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. Film: HD 18x24 cm CP: 4 cm superior to upside EAM CR: 15 caudal to pass through the downside TMJ.,17,Axiolateral (Schller 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.,18,Axioanterior Oblique (Stenvers for mastoids) B,For advanced pathology of temporal bone, e.g., acoustic neuroma. Both sides are to be examined. Patient prone or erect, IOML 90 to film, chin adjusted so that head is rotated 45 oblique with the couch, side of interest down, downside mastoid region centered to film. Film: HD 18x24 cm CP: 7 10 cm posterior, and 1.25 cm inferior to upside EAM to exit through downside mastoid process. CR: 12 cephalic.,19,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,20,Tangential Superoinferior (Axial) (nasal bones) S,For fractures of the nasal bones. Patient prone or in the erect sitting, chin extended and rested on cassette, angle support under film, glabelloalvolar line (GAL) 90 to cassette, long narrow cone used Film: HD 18x24 cm (or occlusal film). CP: Naison (parallel to GAL). CR: Angle as needed to ensure CR is parallel to GAL.,21,Submentovertex (SMV) S,22,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 patients 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,23,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 patients 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,24,For #s of the mandible and TM joint. Tube and film attached at starting position, chin rest raised to same level as patients 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, patients lips placed together, tongue on roof of the mouth. Film: HD 23x30 cm, or curved non-grid cassette CP: Fixed CR and FFD. For TMJ, another film must be done with open mouth.,Submentovertex (SMV) (for zygomatic arches) B,25,For #s, neoplastic, or inflammatory processes of the zygomatic arch (usually taken as a soft-tissue technique). Patient supine or erect sitting, chin raised, neck hyperextended till IOML is parallel to film, MSP 90 to couch top. A pillow under patients back allows for sufficient extension. Film: HD 18x24 cm CP: Midway between zygomatic arches (4 cm inferior to mandibular symphysis). CR: 90 to film.,Oblique inferosuperior Tangential (for zygomatic arches) S,26,For #s, neoplastic, or inflammatory processes of the zygomatic arch. Specially useful in case of depressed zygomatic arches (skull trauma). Patient positioned as for the SMV, head rotated 15 toward side of interest, then chin tilted 15 toward side of interest. Film: HD 18x24 cm CP: Zygomatic arch of interest. CR: 90 to IOML and film.,Parieto-orbital (Rhese View) for optic foramina S,27,For bony abnormalities of the optic foramen. Both sides must be done for compa