1、MR、MSCT 在儿科的应用首都医科大学附属北京儿童医院影像中心孙国强 计算机体层摄影（Computed tomography,简称 CT）目前已广泛应用于儿科各系统检查。其密度分辨率高，横断面图像，可进行图像后处理及多方向的重建。可以显示 X线照片无法显示的器官和病变。解剖关系清楚，病灶显示良好。CT的使用使儿科病变检出率，诊断的准确率有了明显地提高。使儿科影像学诊断水平发生了质的飞跃。近年来 CT技术有了飞速地发展，多层螺旋 CT（multislice spiral CT，简称 MSCT）每次扫描获及 16-64层图像，0.625mmx64 单圈覆盖范围 40mm，扫描速度快，管球旋转一圈
2、最短 0.35s，球管热容量大 8M，最大输出电流800mA，重建功能强，一键式 CT血管造影成像（CTA）实质性器官容积灌注，图像融合等，多种后处理软件。当前双源 CT、宝石能谱、128 排 256层，32 排640层 CT已投入临床使用。1.5T磁共振（MRI）三维图像，解剖关系清楚，组织分辨率高,增强病变显示良好，MRA 可了解大血管及主要分支，MRU，MRCP 观察泌尿系疾病及肝胆胰疾病，病变检出率及诊断准确率提高。1.5T 磁共振在儿科颅脑、脊髓、大血管畸形、肝胆胰脾肾的先天畸形及占位病变有着广泛的用途。3.0T MRI 在三甲医院已广泛投入临床使用。2011 年 3月国内儿童医院第
3、一台 3.0T MR已在北京儿童医院为患儿服务。MR、CT 检查应严格掌握适应征，必须与普通 X线检查、B 超共同使用，互相取长补短才能不断提高儿科影像诊断水平。第一章 中枢神经系统第一节 小儿颅脑 CT解剖特点一.颅骨：刚出生新生儿，经产道挤压，顶枕骨重叠，颅骨变形，数天内可恢复。新生儿颅骨，主要是顶骨常可骨化不全，甚至完全未骨化。前囟及后外侧囟约在1.52 岁闭合，后囟及前外侧囟生后 3个月以内已闭合。颅缝和颅底软骨连合新生儿期较著明，宽约 35mm ，12 岁不超过 12mm 。颅顶部颅缝大约 13岁开始愈合，额缝 23 岁关闭，10%可保留终生。缝间骨和囟门内骨多见于人字缝，可单发或多
4、发。为正常变异。囟门和颅缝的闭合标志胎儿膜性骨骺残余部分的消失。颅骨的生长分化主要发生在生后 2年内。内、外板，板障间隙，血管沟等于生后 2年内逐渐分化形成。矢状缝两侧的蛛网膜颗粒压迹在儿童并非少见。二.颅内及脑组织新生儿蛛网膜下腔及大脑侧裂池较著明，大脑纵裂池不宽于 3mm。基底池著明可持续至 56 岁。新生儿透明隔常未融合，留下含脑积液之腔，位于双侧脑室额角之间称为透明隔间腔，即第 5脑室，其后方可见穹隆间隙，称为穹隆间腔，即第 6脑室，多数几个月内融合，少数持续至成年。其宽径不超过10mm。脑生长发育于出生前后发育最迅速，脑细胞的生长分化移行和髓鞘化的过程，脑沟，脑裂的出现，其发育过程持
5、续至成人早期。髓鞘形成于胚胎第 6月，90%的脑髓鞘化发生在 2岁以内。髓鞘形成从中心至周围，从背侧至腹侧，从尾端向头侧发展。其中侧脑室三角区背侧及上部白质直至 1530 岁才形成髓鞘。评价脑髓鞘形成需用磁共振检查。了解小儿不同阶段髓鞘形成情况对评价小儿脑发育是十分重要的。新生儿脑实质 CT值较成人偏低，如脑灰质为31.82.67Hu （成人 36.33.6 Hu） ，脑白质为 22.82.63 Hu（成人27.13.6 Hu） 。这是因为出生时脑实质含水量 85%至 2岁时为 82%，与此同时，脑脂质增加，铁质沉着。因此 2岁小儿脑实质 CT值可作为正常诊断的依据。三.颅内钙化10岁以下小儿
6、生理性钙化较成人少见，小儿生理性钙化包括：（一）松果体钙化，9 岁以下少见，表现为小颗粒样钙化，单发多见，亦可多发，一般小于 10mm。（二）缰联合钙化，位于松果体前几毫米靠近三脑室，10 岁以后出现呈 C形钙化。（三）脉络丛钙化，见于侧脑室三角区呈颗粒样钙化，3 岁即可出现，但 9岁以前不常见。（四）脑镰、小脑幕、岩床韧带和床间韧带、蛛网膜粒凹硬膜钙化偶见。以上生理性钙化 10岁以后随年龄增长发生率增加。小儿颅内异常钙化：（一）甲状旁腺机能减退，小儿基底节区对称性钙化，有时分布可更广泛。 （二）Fahr 氏病又称特发性家族性脑血管亚铁钙沉着征。表现为广泛脑内钙化，以基底神经节和小脑齿状核明显
7、。 （三）线粒体脑疾病，基底节之双侧壳核对称性钙化，可合并广泛脑皮质萎缩，脑室扩大。 （四）宫内感染性疾病，新生儿 Torch综合征。 （五）其他，结节性硬化，颅面血管瘤综合征，神经纤维瘤病，结核钙化，脑囊虫病，血管性钙化，肿瘤性钙化，外伤硬膜下血肿钙化等。第二节 新生儿低氧缺血性脑病新生儿低氧缺血性脑病（Hypoxic ischemic encephalophy ，简称 HIE）是围产期窒息，呼吸道感染，胎粪吸入败血症等因素造成脑组织缺血，使脑细胞发生不同程度的水肿，变性。如治疗不及时或病情进一步加重可使脑细胞破坏、软化、液化形成囊变。引起脑功能障碍和脑萎缩。低氧血症可改变毛细血管的通透性，
8、引起血管破裂并发颅内出血。一.临床表现：HIE 足月儿发病率高。北京儿童医院半年内新生儿头颅 CT检查 325例，HIE 占 90%。临床表现为意识，肌张力和原始反射的改变。二.CT 表现：根据病变范围有人将 HIE分为轻、中、重三度。（一）轻度：多位于双侧额叶脑白质内小片状低密度区，多呈对呈分布，范围不超过两个脑叶，CT 值 18Hu以下。（二）中度：脑实质内低密度区范围超过两个脑叶，脑灰白质分界不清，对比模糊，脑沟消失，脑室变小，可合并颅内出血，多见于大脑纵裂后部。（三）脑实质内弥漫分布低密度区，部分病理累及基底节区，但小脑、脑干一般不受影响。脑室可明显变窄合并颅内出血。三.预后：HIE
9、的复查应在 2周，轻度及中度多数可恢复正常或明显好转，临床很少后遗症。但重度的 35%死亡。存活者常有后遗症。第三节 新生儿颅内出血新生儿颅内出血主要由脑血管发育不良，低氧缺血及产伤造成。早产婴发生率高，出血多发生于室管膜下并易扩散。足月儿由于血管调节，凝血机制生后 12 天仍较差，造成出血，多见于蛛网膜下腔，硬膜下，大脑镰，天幕部位。常合并 HIE及产伤。一.临床表现：患儿易激惹，尖叫，心率、呼吸加速，嗜睡，前囟隆起和体温不稳定等。但亦有少数新生儿颅内出血，无临床症状。二.CT 表现：（一）蛛网膜下腔出血：多见于小脑天幕，直窦，其次为基底池，侧裂池等部位。呈现线样， “M”“Y”形高密度影，
10、外形增粗，边缘模糊。矢状窦及窦汇旁出血可出现窦汇的空三角征，如出血偏一侧可出现半个三角征。（二）硬膜下出血：多因足月儿产伤使大脑镰及小脑幕撕裂，常伴临近静脉或静脉窦的损伤。表现为颅板下新月形高密度影，有时与蛛网膜下腔出血难以区别。硬膜下出血常有占位效应。 （三）其他部位出血：硬膜外出血常伴颅骨骨折，多系统产伤，占位效应轻。脑内出血见于外伤或重度 HEI，常有占位效应。高密度出血区周围常伴低密度水肿带。室管膜下出血及脑室内出血，多见于早产婴，尤其体重低于 1500g，孕期不足 35周者，发病率高达 50%以上。第四节 胎儿及新生儿感染胎儿及新生儿感染是经胎盘或产道感染的疾病，总称 TORCH综合
11、征。包括先天性脑弓形体病（toxoplasmosis） ；风疹性脑炎（Rubella） ；脑巨细胞包涵体病（ Cytomegalovirus） ；单纯疱疹病毒 II型脑炎（ herpes encephalitis simplexII） ；其他病原体（Other agents） 。一.先天性脑弓形体病：是由鼠弓形体引起的人畜共患的传染性疾病。胎儿时期在母体子宫内感染。出生时或几周后出现症状。小头、智低、脑瘫、癫痫、双目失明。CT 表现为：小头畸形，基底节，皮质脑室周围广泛分布的钙化，脑积水，脑实质片状低密度区，常见积水性脑畸形，孔洞脑畸形二.风疹性脑炎：多为妊娠早、中期宫内感染，表现为小头，智低
12、，眼球小，白内障，癫痫。CT 表现为小头畸形，基底节，脑干，皮质，脑室周围的钙化。三.巨细胞包涵体病：常见于宫内径胎盘感染，多见于早产婴及小样儿。表现为小头，智力发育迟缓，听视力障碍，癫痫。CT 表现为：小头畸形，结节或条形钙化分布于室管膜下，脑室周围。弥漫性脑萎缩使脑室扩大，脑实质减少。常见积水型无脑畸形，多小脑回，半巨脑畸形。四.单纯疱疹 II型病毒脑炎：于妊娠早期感染，可引起小头，脑萎缩，脑软化及积水型无脑畸形。表现为嗜睡，癫痫，黄疸，肝大等。CT 表现为广泛分布的片状水肿及缺血性低密度灶。导致囊性脑软化，脑实质变薄，脑室扩大。脑室周围和皮质下区出现斑片状或脑回形钙化。第五节 晚发性 V
13、itK缺乏引起颅内出血晚发 VitK缺乏症是由于 VitK及凝血因子、缺乏造成的。这些凝血因子又称 VitK依赖因子。在肝脏合成时必须有足够的 VitK参与。当 VitK缺乏时，这些凝血因子合成减少，导致出血。由于母乳内 VitK含量少。造成本病大多数为纯母乳喂养的足月儿。一.临床表现：发病时间为 2周至 3个月，绝大多数发生在 1-2月内。患儿凝血及凝血酶元时间延长，有出血倾向。无外伤史，突然呕吐，意识障碍，抽搐等。二.CT 表现：脑实质及蛛网膜下腔出血多见，其他可发生在脑室，硬膜下腔。有时可出现淤血平面。出血压迫血管或血管痉挛造成脑梗塞者多见 ，可发生在血肿周围或对侧，呈大片低密度区。造成
14、鞍上池，脑干周围脑池变形，狭窄，移位造成脑疝。中线结构移位多见。本病发生率不高，但预后不良，多数遗留永久性神经系统后遗症，部分病例死亡。（英文版 ） Two regulations promulgated for implementation is in the party in power for a long time and the rule of law conditions, the implementation of comprehensive strictly strategic plan, implementation in accordance with the rules
15、and discipline to manage the party, strengthen inner-party supervision of major initiatives. The two regulations supporting each other, the adhere to a positive advocate, focusing on morality is of Party members and Party leading cadres can see, enough to get a high standard; around the party discip
16、line, disciplinary ruler requirements, listed as “negative list, focusing on vertical gauge, draw the party organizations and Party members do not touch the“ bottom line “. Here, the main from four square face two party rules of interpretation: the first part introduces two party Revised regulations
17、 the necessity and the revision process; the second part is the interpretation of the two fundamental principles of the revision of laws and regulations in the party; the third part introduces two party regulations modified the main changes and needs to grasp several key problems; the fourth part on
18、 how to grasp the implementation of the two regulations of the party. and revised the necessity and revised history of the CPC Central Committee the amendment to the Chinese Communist Party members and leading cadres honest politics several guidelines and column 1 by 2015 to strengthen party laws an
19、d regulations focus. Two party regulations revision work lasted a Years, pooling the wisdom of the whole party, ideological consensus, draw historical experience, respect for the wisdom of our predecessors, which reflects the unity of inheritance and innovation; follow the correct direction, grasp t
20、he limited goals, adhere to the partys leadership, to solve the masses of the people reflect a focus on the problem. The new revision of the and , reflects the partys 18 and the eighth session of the third, the spirit of the fourth plenary session, reflecting the experience of studying and implement
21、ing the General Secretary Xi Jinping series of important speech, reflects the partys eighteen years comprehensive strictly practice. (a) revised two regulations of the party need of in based on revised, the promulgation and implementation of January 2010, to strengthen the construction of the contin
22、gent of leading cadres play an important role. But with the party to manage the party strictly administering the deepening, has not been able to fully meet the actual needs. Content is too complicated, “eight prohibition, 52 are not allowed to“ hard to remember, and also difficult to put into practi
23、ce; the second is concisely positive advocated by the lack of prohibited provisions excessive, no autonomy requirements; the third is banned terms and discipline law, both with the party discipline, disciplinary regulations repeat and Criminal law and other laws and regulations repeat; the fourth is
24、 to “clean“ the theme is not prominent, not for the existing problems, and is narrow, only needle of county-level leading cadres above. is in 1997 based on revision, in December 2003 the promulgation and implementation, to strengthen the construction of the party play very important role. Along with
25、 the development of the situation, which many provisions have been unable to fully meet the comprehensive strictly administering the practice needs. One is Ji law, more than half of the provisions and criminal law and other countries laws and regulations Repetition; two is the political discipline r
26、egulations is not prominent, not specific, for violation of the party constitution, damage the authority of Party Constitution of misconduct lack necessary and serious responsibility to pursue; third is the main discipline for the leading cadres, does not cover all Party members. Based on the above
27、situation, need to and the two is likely to be more relevant regulations first amendment. By revising, really put the authority of Party discipline, the seriousness in the party tree and call up the majority of Party members and cadres of the party constitution of party compasses party consciousness
28、. (II) two party regulations revision process the Central Committee of the Communist Party of China attaches great importance to two regulations revision . Xi Jinping, general books recorded in the Fifth Plenary Session of the eighth session of the Central Commission for Discipline Inspection, on th
29、e revised regulations made clear instructions. According to the central deployment, the Central Commission for Discipline Inspection from 2014 under six months begin study two regulations revision. The Standing Committee of the Central Commission for Discipline Inspection 4 review revised. Comrade W
30、ang Qishan 14 times held a special meeting to study two regulations revision, amendment clarifies the direction, major issues of principle, path and target, respectively held a forum will listen to part of the province (area) secretary of the Party committee, Secretary of the Discipline Inspection C
31、ommission, part of the central ministries and state organs DepartmentThe first party committee is mainly responsible for people, views of experts and scholars and grassroots party organizations and Party members. Approved by the Central Committee of the Communist Party of China, on 7 September 2015,
32、 the general office of the Central Committee of the Party issued a notice to solicit the provinces (autonomous regions, municipalities) Party, the central ministries and commissions, state ministries and commissions of the Party (party), the General Political Department of the military, every 3 people organization of Party of two regulations revision opinion. Central Commission for Discipline Inspection of extensive solicitation of opinions, careful
