影像 整理.doc

总论流空效应*2 ：: In the case of rapid arterial flow, the protons leave the imaging volume between the two RF pulses, no signal is collected, and the arteries are displayed dark on the MR image.根尖片分角线投照技术：X-ray beam perpendicular to line bisecting angle formed by film and long axis of tooth。It may cause imaging distorted during posterior teeth projection.远距平行投照技术：Film/tooth/ring all parallel，X-ray beam perpendicular to tooth and film牙颈部buruout征: Diffuse radiolucent areas with ill-defined borders may be apparent radiographically on the medial or distal aspects of teeth in the cervical regions between the edge of the enamel cap and the crest of alveolar，which results in decrease x-ray absorption in these areas .T1加权像*short TR(500msec), short TE(2000msec), long TE(60msec)-T2-weighted image（T2WI，T2加权图）T1-weighted imaging: the contrast between tissues is due mainly to their T1 relaxation properties.牙科X线数字影像技术(Digital radiograph):Composed of : X-ray machine，Sensor(CCD)，Computer，Monitor，Printer牙体牙周病变根尖周脓肿，根尖周囊肿，根尖周肉芽肿的影像学表现 Located at the apex of affectd teeth: Chronic periapical abscess（脓肿）Periapical granuloma（肉芽肿）Peiapical cyst（囊肿）Sizeuncertain1cm1-2cm,or largershapIrregularityround or oval round or oval Opical densityLow and unevenSoft tissue density, unevenLow and evenperipheryill-defined, Without cortical boundaryWell define,Without cortical boundarywell defined, With cortical boundarySurrounding boneMay increase the bone formationNormal Normal 假性牙瘤与真性牙瘤的鉴别Differential diagnosis between Cemental hypoplasia and benign cementoblastoma :Age and SexLocationRadiographic featureCemental hypoplasia40 years old femaleMandibular incisorMultiple fociA radiopaque mass of comparatively high density, which is encircled by a thin,radiolucent line .The lamina dura and periodontal ligament is intact.Benign cementoblastoma25years old maleMandibular molar region , single focusAn uneven radiopaque attached to the root of affected tooth, surrounded by a radiolucent band. Root absorbtion and fusion may occur.颌骨炎症线状骨膜反应*2 linear periostealreaction：Appears as a thin , faint , radiopaque line adjacent to and almost parallel or slightly convex to the surface of the bone , separated by a radiolucent band from the bone surface.放射性骨坏死的影像学表现1. early phase: loss of sharpness of the trabeculae2. ill-defined , irregular mottled(斑片状的), moth-eaten radiolucent destruction 3. sequestrums can be seen，sequertrums do not separate.4. periosteal reaction is uncommon5. radiation caries, mostly affectd the neck of tooth.牙源性中央性颌骨骨髓炎的鉴别诊断:Osteosarcoma : 1. Affected tooth: radiolucent lesion surrounding the apex of affected tooth/ none2. Bony destruction: clear margin,sequestrum / ill-defined, tumorous osseous structure no sequestrum3. Periosteal reaction: linear periosteal reaction/ sunburst spicules, codmans triangleFibrous dysplasia : 骨形成发生于颌骨内/ 骨形成发生于皮质外Langerhans histocytosis : 无骨硬化和死骨形成。肿瘤磨砂玻璃样征*2：in fibrous dysplasia, the ossiform tissue and fibrous tissue mixed together, forming the structureless, homogeneous radiopaque, looks like ground-glass. 在上颌窦癌的检查中CT相比X线有哪些优势1. Show the internal structure of the lesions directly2. The destruction of each wall can be seen clearly3. Show the surrounding structures invaded directlyfloatingteeth*3：The supportive structures(alveolar bone、periodontal ligament) of teeth is destroyed by the malignant tumor, in radiograph the teeth is locating in the alveolar bone without any supportive tissue under the teeth, looks like floating in the bone.牙源性腺样瘤的影像学表现Young female adult, maxillary canine region,absence of permanent teeth, with entired capsule. Unilocular radiolucent area in maxillary canine region, with unerupted tooth(canine) and small calcifications in the lesion, bone expansion is slight. 颌骨骨肉瘤的影像学表现 posterior areas(mandible and maxilla), ramus is commonly affected.Change of bony structure: ill-defined lesions, osteogenesis and osteolysis, floating teeth, cortical bone destruction, pathological fracture. Formation of tumorous osseous structure, sunray spicules.Periosteal reaction: lamellar; Codmans triangle. Soft tissue image. Metastasis of lung.颌骨成釉细胞瘤的主要X线表现，与牙源性角化囊性瘤的鉴别*2Ameloblastoma 3049years old , molar-ramus region, well defined corticated margine, Buccal expansion, Tooth displacement, containing tooth, no calcification, root absorbtion.1. Radiological types:1) Multilocular type: The size of chambers differs obviously, chambers overlap but the septums are clear and sharp.2) Honeycomb type:Always with one larger chamber, numerous small chambers similar in size, the septum is coarse and thick3) Unicystic type: Single radiolucent area,come incisures can be found near the margin.4) Malignant type: obviously expansion of mandible is rare, but bone destruction is prominent, septums break down,some multilocular evidence(incisures) can be found at the margin of the lesion.2. Change of bone: cortical bone expansion(buccal)，cortical bone destruction、interruption, regional hyperosteogeny and osteosclerosis.3. Change of tooth: tooth displacement ,contain teeth in the lesion, dental root absorbtion(knife-edge like), lamina dura disappear.4. Without calcification.Keratocystic odontogenic tumor: 2030 and 50 years old 1. Unilocular or multilocular(the loculi are almost equal in size) radiolucent area in mandible.2. Grow along the long axis of mandible.3. May have a scalloped outline4. Causing lingual expansion (slightly)5. Tooth absorbtion not common, sometimes may be oblique absorbtion.6. The maxillary cyst may occupy the entire maxillary antrum7. Nevoid basal cell carcinoma syndrome: Multiple OKCs of the jaw, skin basal cell carcinoma, calcification may appear in skull , skeletal abnormalities indluding bifid rib, cervical rib成釉细胞瘤影像学表现和主要鉴别诊断颌骨骨折上颌骨骨折分型Le Fort 1 ：Inferior part of piriform aperture ，basal part of maxillary alveolar bone，maxillary tuberosity，pterygoid processLe Fort 2 ：Nasal bone，infra-orbital rims ，floors of orbits ，inferior of the zygomatic bone，pterygoid processLe Fort 3 ：Nasal bone ，frontal process of maxilla，floors of orbits，superior of the zygomatic bone，pterygoid process涎腺疾病ball in hand appearance: Benign tumor of salivary glands, the ducts are compressed or smoothly displaced around the lesion, appearing like a hand(ducts) holding a ball(the tumor).怀疑颌下腺结石的病人如何做X线检查，有哪些可能的影像学表现First of all, take transsection mandibular occlusal film and lateral film of submadibular gland to find out whether the sialolith is a radiopaque one. We may find oval or round shape radiopaque goes along the duct, ususlly have a homogeneous radiopaque internal strueture. If no positive finding is made by plain film, we can use sialography to detect the radiolucent sialolith. Radiolucent sialoliths appear as ductal filling defects, The contrast agent may be obstructed by the sialolith or go around it, contrast agent retention can be seen in proximal duct. The proximal duct may be dilated. 阴性涎石主要检查方法和影像表现Lateral film, panoramic, CT scan 类圆形充盈缺损沿导管走行，或远端导管不显影，或造影剂绕过结石至远端导管，造影剂排空延迟，远端导管扩张。慢性阻塞性腮腺炎与慢性复发性腮腺炎的影像学鉴别要点Chronic obstructive sialadentitis always affect adults, Sausage-string appearance of the main duct can be seen(produced by alternate strictures and dilations of duct). As the disease progress, the branch ducts and terminal ducts may become dilated. In latter phase, punctuate and globular dilatation can appear. While the chronic recurrent sialadentitis always affect the children, the main duct and branch duct ususlly intact, or slightly dilate if affected. 慢性复发性腮腺炎的影像学表现*2Always affect the children, can cure itself when growing up. Terminal ducts dilation appear as punctuate, globular, cavitary collections of contrast agent, and distribute throughout the gland. Elimination function declines, May affect the main duct,causing mildly dilation of main duct. Terminal ducts dilatation will decrease by dynamic detection.点扩征: Terminal ducts dilation appear as punctuate collections of contrast agent, and distribute throughout the gland。舍格伦综合症的影像学表现和鉴别要点 管壁外渗征Radiographic features:1. Normal shape,bue elimination function delays.2. The alteration of periphery ducts :Stages:1) Terminal ducts dilation appear punctuate dilatation, d1mm,the intraglandular ducts may be narrowed.2) Terminal ducts dilation appear globular dilatation, d=12mm, the intraglandular ducts become not evident.3) Terminal ducts dilation appear cavitary dilatation, fewer in number and less uniformly distributed.4) Completely destruction of the gland , ducts can not be imaged.3. The alteration of main ducts:1) Main duct appears sausage-string appearance2) Duct wall exudation sign:the smooth and sharp border of duct wall disappears, local dilation can be seen ,resulting in feather-like or onion-skin appearance.4. Afferens atrophia: the parenchyma can not be seen, only main duct and branch ducts are imaged.5. Tumor like change: 1) Benign :ball-in-hand sign, regular filling defect.2) Malignant :ill-defined filling defect, contrast media overflow.Differential diagnoses :1. Tumor of salivary glands: Sjogrens syndrome has terminal ducts dilations.2. Adult chronic recurrent sialadentitis: Clinical histo