《new-skull头颅影像学》由会员分享，可在线阅读，更多相关《new-skull头颅影像学（29页珍藏版）》请在金锄头文库上搜索。
1、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
2、 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 m
3、inimizing 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 di
4、sease, 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: Exi
5、ts 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 el
6、ongated 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)
7、 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.
8、 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 oste
9、omyelitis, 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 projec
10、tion 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 a
11、rch 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
12、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 sinu
13、s (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
14、 . 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
15、 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 s
