甲状腺病变CT诊断

甲状腺病变CT诊断 1、甲状腺的CT解剖简介 甲状腺分左、右两叶，中间以峡部相连，呈蝴蝶形，峡部相当于蝶体，两叶相当于蝶翼。甲状腺上缘起自甲状软骨下方或中部，下缘约平第6气管环，甲状腺峡部居中，位于气管正前方，左、右两叶分别居气管左、右两侧。正常甲状腺的前后径(即厚度)2,3 cm，左叶或右叶的左右径(即宽度)2,3 cm，上下径(即长度)6,7 cm。女性的各径略比男性为小。由于正常甲状腺含碘量比周围软组织高，故CT平扫呈高密度，密度均匀，边缘清楚，CT值约70?10 HU，增强扫描后甲状腺呈均匀性显著强化。峡部上缘有时出现一个锥状叶，其尖端向上，是胚胎时期甲状舌管的遗迹，不要误为病变。 2、甲状腺的CT检查方法 甲状腺CT扫描的范围是:上界在甲状软骨上缘，下界至第七颈椎上缘。层厚5 mm，连续扫描，以减少漏层。一般先做平扫，然后作常规增强扫描。常规增强扫描时经肘静脉快速注入60%的有机碘水溶液80,100 ml后，立即进行扫描。 3、甲状腺常见病变的CT诊断 3.1 弥漫性甲状腺肿大 弥漫性甲状腺肿大是一种病征，以下四种常见疾病是引起甲状腺弥漫性肿大的常见原因。 3.1.1 单纯性甲状腺肿(simple goiter) 高原、山区居民的饮食中长期缺碘，导致血中甲状腺素水平下降，并引起脑垂体前叶分泌多量的促甲状腺素，促使甲状腺弥漫性肿大。因此，本病又称为“地方性甲状腺肿”。此外，青春期、妊娠期或绝经期妇女，有的也可发生弥漫性甲状腺肿大。这是人体对甲状腺素需要增加所引起的生理性甲状腺肿大。这种生理性肿大常在成年或分娩后自行缩小。单纯性甲状腺肿临床上除甲状腺肿大外，无其它症状和体征。 3.1.2 原发性甲状腺功能亢进(原发性甲亢，又称Grave氏病) provisions of paragraph 6.5 submission of complete information. Monitoring inspection and safety assessment of the implementation of the outcome of the owners of the relevant regulations. 10.11 the completion at the end of the contract period, we will transfer to the owners of all monitoring facilities, engineering data, documents, reports and other project-related content. For monitoring facilities, replaceable equipment availability monitoring instruments should be 100%, not replacing equipment availability monitoring instruments should be 95% or more. Curtain Grouting in the 11th Chapter 11.1 project overview the on curtain Grouting works primarily for River yongxing secondary hydropower station dam Foundation curtain grouting, quantities of 200m. Dam Foundation curtain Grouting in dam concrete pouring is complete, reaches a certain intensity, agreed by the supervising engineer and began construction. 11.2 11.2.1 General requirements we are responsible for the procurement of materials, transport, storage, keeping drilling and apart from the employer's manpower required to grout materials for all materials. Admixture, admixture of each procurement shall meet the relevant quality 原发性甲亢是指甲状腺肿大同时伴有甲状腺激素分泌过多的状态。病人年龄多在20,40岁，女性多见。临床症状主要是甲状腺肿大、心悸、性情急躁、易激动、怕热多汗、多食而体重减轻、月经失调、双手颤动、突眼等。血中T3(血清三碘甲状腺原氨酸)和T4(血清四碘甲腺腺原氨酸，即甲状腺素)增高。 3.1.3 慢性淋巴细胞性甲状腺炎(又称Hashimoto(桥本)氏甲状腺肿) 本病是自身免疫性疾病，因自身抗体明显升高，故又称自身免疫性甲状腺炎。女性多见(95%)，好发于40岁以上的病人。临床上以颈部(甲状腺)肿大、变硬多见，病程较长(1,2年)。体检甲状腺弥漫性肿大，质韧、硬，无明显结节。血中自身抗体滴定度升高，T3、T4降低，但甲状腺摄碘131量正常对诊断有助。 3.1.4 亚急性甲状腺炎(又称病毒性甲状腺炎或肉芽肿性甲状腺炎) 常继发于上呼吸道感染。可能是由于病毒感染破坏了部份甲状腺滤泡，滤泡中释放出来的胶体引起甲状腺组织内的异物样反应所致。临床上见甲状腺中度肿大，较硬，压痛。体温升高、血沉加快。T3、T4增高(因甲状腺滤泡破坏后，释放的甲状腺激素增加)，但甲状腺摄碘131量显著降低对诊断有参考价值。本病发病前1,2周常有上呼吸道感染的历史。病程约3个月，愈后甲状腺功能多复常。 上述四种引起弥漫性甲状腺肿大的病变，其CT表现大致相同。主要是:CT平扫见双侧甲状腺弥漫性肿大，密度较正常甲状腺减低(正常平扫时甲状腺CT值约70?10 HU)，密度均匀，边缘规则清楚。增强扫描后见增大的甲状腺呈轻度强化，密度大致均匀。有的原发性甲亢病人，于增强后则见肿大的甲状腺强化较显著或腺体内出现一些细小的强化血管影，反映了本病腺体内血管增多的病理改变。在桥本氏甲状腺肿，增强后有的可出现不均匀片状强化。总之，上述四种疾病的CT平扫和增强扫描，肿大的甲状腺内均无明确的结节影存在。 3.2 结节性甲状腺肿(又称腺瘤样甲状腺肿，adenomatous goiter) 缺碘引起的弥漫性甲状腺肿大若未经及时治疗，病变发展可使扩张的滤泡集成多个大小不等的结节，逐渐形成结节性甲状腺肿，这些增生的结节并非真正的腺瘤。结节因供血不良，则可发生坏死、出血、囊变。临床症状主要是肿大的结节增大后(有的结节可达数百克，甚至数公斤)，可压迫气管、食管和血管，引起呼吸困难、吞咽障碍和头面血液回流障碍的表现。本病后期可出现继发性甲亢，此时称毒性结节性甲状腺肿(又称Plummer氏病)。病人多在40岁以上，有甲亢症状，心肌损害多见，但无突眼。 provisions of paragraph 6.5 submission of complete information. Monitoring inspection and safety assessment of the implementation of the outcome of the owners of the relevant regulations. 10.11 the completion at the end of the contract period, we will transfer to the owners of all monitoring facilities, engineering data, documents, reports and other project-related content. For monitoring facilities, replaceable equipment availability monitoring instruments should be 100%, not replacing equipment availability monitoring instruments should be 95% or more. Curtain Grouting in the 11th Chapter 11.1 project overview the on curtain Grouting works primarily for River yongxing secondary hydropower station dam Foundation curtain grouting, quantities of 200m. Dam Foundation curtain Grouting in dam concrete pouring is complete, reaches a certain intensity, agreed by the supervising engineer and began construction. 11.2 11.2.1 General requirements we are responsible for the procurement of materials, transport, storage, keeping drilling and apart from the employer's manpower required to grout materials for all materials. Admixture, admixture of each procurement shall meet the relevant quality CT上本病表现为双侧弥漫性(有时为一侧性)增大的甲状腺内，平扫和增强扫描都见多个大小不等的、结节状低密度区，边缘多较清楚。结节内如有出血，则平扫时结节变为高密度。如有囊变，则呈水样密度，有时囊变区可见结节，不要误为囊变区癌变。但是，结节性甲状腺肿是可以发生癌变的。 3.3 甲状腺囊肿 甲状腺囊肿包括胶样囊肿和非胶样囊肿。CT上表现为单个囊性病变，密度均匀，边缘清楚，增强扫描后无强化。胶样囊肿因含蛋白质物质较多，CT值比非胶样囊肿高。 3.4 甲状腺腺瘤 甲状腺腺瘤是良性肿瘤，女性多见，以20,40岁好发，病程缓慢可达数年。除甲状腺肿物外，无自觉症状。瘤内如有突然出血，肿瘤可迅速增大。病理上分为滤泡状腺瘤和乳头状囊腺瘤，以前者多见。 滤泡状腺瘤在CT上平扫为孤立性单发低密度结节(出血的则为高密度)，密度均匀，边缘清楚。增强后呈均匀性强化，密度仍低于正常甲状腺，有的病例可见囊变区或钙化点。乳头状囊腺瘤CT上表现为实性结节中部分或大部分瘤区内出现囊变区，囊壁较厚，较规则，有时囊壁上可见小乳头突起。 3.5 高功能甲状腺腺瘤(又称功能自主性甲状腺腺瘤或毒性甲状腺腺瘤) 本病少见。病理上见甲状腺内有单个的、自主性高分泌功能的腺瘤结节，结节周围的甲状腺组织呈萎缩状态。临床上病人有甲亢症状，但无突眼。 CT表现与甲状腺腺瘤相同，但大多数为实性结节。 3.6 甲状腺癌 甲状腺癌可以原发，也可以是甲状腺腺瘤或结节性甲状腺肿恶变而来。病理上可分为乳头状腺癌、滤泡状腺癌、未分化癌和髓样癌，其中乳头状腺癌多见于年轻人，滤泡状腺癌多见于中年人，未分化癌则好发于老年人，女性多于男性。临床上以颈部结节或肿块就诊。晚期病人常有声嘶、吞咽障碍、呼吸不畅等症状。为肿瘤压迫喉返神经、食管、气管所致。 CT平扫和增强扫描可见甲状腺内有结节状或肿块状低密度病变，边缘分叶及不清，密度不均匀，或有不规则坏死区。癌肿可双侧侵犯，可累及颈静脉引起颈静脉内癌栓。还可侵provisions of paragraph 6.5 submission of complete information. Monitoring inspection and safety assessment of the implementation of the outcome of the owners of the relevant regulations. 10.11 the completion at the end of the contract period, we will transfer to the owners of all monitoring facilities, engineering data, documents, reports and other project-related content. For monitoring facilities, replaceable equipment availability monitoring instruments should be 100%, not replacing equipment availability monitoring instruments should be 95% or more. Curtain Grouting in the 11th Chapter 11.1 project overview the on curtain Grouting works primarily for River yongxing secondary hydropower station dam Foundation curtain grouting, quantities of 200m. Dam Foundation curtain Grouting in dam concrete pouring is complete, reaches a certain intensity, agreed by the supervising engineer and began construction. 11.2 11.2.1 General requirements we are responsible for the procurement of materials, transport, storage, keeping drilling and apart from the employer's manpower required to grout materials for all materials. Admixture, admixture of each procurement shall meet the relevant quality 犯或压迫周围器官及组织，如侵犯颈前肌和气管，钙化常可见到。 甲状腺癌与甲状腺良性结节的CT鉴别诊断，主要是癌肿边缘不清、瘤内密度不均及不均匀强化，或有不规则坏死区。良性结节多边缘清楚，密度均匀及均匀性强化。淋巴结增大对癌肿诊断有帮助。颈静脉内出现癌栓及颈前肌侵犯等更支持甲状腺癌。 3.7 少见的甲状腺瘤 良性的血管瘤、纤维瘤、畸胎瘤、平滑肌瘤等。恶性的有淋巴瘤、平滑肌肉瘤等。其CT表现与身体其它部位的相应肿瘤类同。 4、甲状腺常见病变的CT鉴别诊断 以CT表现为依据，甲状腺病变可分为以下几类病变来进行鉴别诊断。 4.1 甲状腺弥漫性肿大的病变 CT上表现为双侧甲状腺对称性弥漫性增大，密度大致均匀或略有不均，但无明确的结节病变存在。这类病变常由以下疾病引起，他们的临床表现，在CT鉴别诊断上比CT征象更为重要。 (1)单纯性甲状腺肿:除甲状腺弥漫性肿大外，临床上无其它异常。 (2)原发性甲亢:临床上有不同程度的甲亢表现。 (3)慢性淋巴细胞性甲状腺炎:临床上病程缓慢(1,2年)，肿大的甲状腺质硬，T3、T4降低而甲状腺摄取碘131量正常，血中自身抗体滴定度升高。 (4)亚急性甲状腺炎:临床起病较急，发热，甲状腺肿大且疼痛明显，血沉升高，T3、T4增高而甲状腺摄取碘131量却显著减少。 4.2 甲状腺多结节病变 CT上表现为甲状腺内有多个结节状低密度病灶。这类病变常由以下疾病引起: 4.2.1 结节性甲状腺肿 本病的CT特征是:结节双侧均为多个，类圆形，边缘清楚，结节多发生在双侧甲状腺弥漫性肿大的基础上，常以实性结节与囊变或出血性结节共存为其特征。临床上除颈部肿物及肿物压迫的相应症状外，无其它症状。病程长达数年至数十年。 4.2.2 毒性结节性甲状腺肿 本病CT特征与结节性甲状腺肿相同，但临床表现不同。本病临床上有甲亢表现。 4.2.3 甲状腺癌腺内播散 本病由主癌灶与周围的子癌灶一起，形成了甲状腺内的多结节病变。这种多结节病变多发生在一侧甲状腺，且数目较少，其中主癌灶较大，边缘不规则。当然，有时子癌灶也可在对侧甲状腺内。 主癌灶呈低密度且密度不均，边缘不规则或不清楚，提示癌肿边缘呈浸润生长。 子癌灶多与主癌灶同侧，比主癌灶为小，低密度实性病灶，边缘大致清楚，无坏死囊变。 4.2.4 甲状腺转移癌 本病少见，原发癌多为黑色素瘤、乳腺癌、肾癌和肺癌。 CT上表现为双侧甲状腺内多个低密度小结节，实性，少有囊变。结合临床上有原发肿瘤史，诊断不难。 provisions of paragraph 6.5 submission of complete information. Monitoring inspection and safety assessment of the implementation of the outcome of the owners of the relevant regulations. 10.11 the completion at the end of the contract period, we will transfer to the owners of all monitoring facilities, engineering data, documents, reports and other project-related content. For monitoring facilities, replaceable equipment availability monitoring instruments should be 100%, not replacing equipment availability monitoring instruments should be 95% or more. Curtain Grouting in the 11th Chapter 11.1 project overview the on curtain Grouting works primarily for River yongxing secondary hydropower station dam Foundation curtain grouting, quantities of 200m. Dam Foundation curtain Grouting in dam concrete pouring is complete, reaches a certain intensity, agreed by the supervising engineer and began construction. 11.2 11.2.1 General requirements we are responsible for the procurement of materials, transport, storage, keeping drilling and apart from the employer's manpower required to grout materials for all materials. Admixture, admixture of each procurement shall meet the relevant quality 必须指出:甲状腺多结节病变中，当甲状腺内结节较少(只有2,3个)，边缘清楚，且结节集中在一侧甲状腺时，CT上首先应考虑多发甲状腺瘤和一侧结节性甲状腺肿。这时，如果上述的少数结节全为实性，无囊变，则多考虑甲状腺瘤。如果囊变较明显或囊、实性并存，则多诊断一侧的结节性甲状腺肿。但在日常工作中，上述两病往往不易鉴别。 4.3 甲状腺单结节病变 CT上表现为一侧甲状腺内有单个低密度结节病灶。这类病变常由以下疾病引起: 4.3.1 甲状腺滤泡性腺瘤 甲状腺瘤以滤泡性腺瘤多见，且多为单个实性结节，以平扫及增强扫描其边缘都光滑清楚为特征。瘤内密度均匀，无坏死、囊变。少数瘤内有局部性坏死，坏死区可以不规则，也可发生囊变，囊变区呈类圆形密度更低区。 4.3.2 甲状腺乳头状腺瘤(又称乳头状囊腺瘤) 乳头状腺瘤为单个的囊、实性结节，囊性可占结节的大部分。囊壁较厚，但边缘清楚，可见壁上结节。增强扫描后囊壁和壁上结节均可强化。 4.3.3 甲状腺癌 甲状腺癌多为单个结节，边缘不规则、不清楚，密度不均匀，瘤内可出现不规则坏死区，囊变较为少见。较大的癌肿常波及对侧，侵犯颈前肌群、颈内静脉、气管，并引起颈部淋巴结转移。 4.3.4 高功能甲状腺腺瘤(又称毒性甲状腺腺瘤) 本病CT上与滤泡性腺瘤表现相似，但临床上却有甲亢表现。 4.3.5 甲状腺平滑肌肉瘤 CT表现与甲状腺癌相似，凭目前经验，术前难以鉴别。 4.4 甲状腺囊性变病 4.4.1 甲状腺囊肿 类圆形水样密度囊性病变，密度均匀，边缘光滑清楚。增强后囊内不强化，边缘更清楚。 4.4.2 甲状腺囊腺瘤(乳头状腺瘤) 囊实性结节，囊壁较厚，可有壁上结节。增强后囊壁和壁上结节强化。 provisions of paragraph 6.5 submission of complete information. Monitoring inspection and safety assessment of the implementation of the outcome of the owners of the relevant regulations. 10.11 the completion at the end of the contract period, we will transfer to the owners of all monitoring facilities, engineering data, documents, reports and other project-related content. For monitoring facilities, replaceable equipment availability monitoring instruments should be 100%, not replacing equipment availability monitoring instruments should be 95% or more. Curtain Grouting in the 11th Chapter 11.1 project overview the on curtain Grouting works primarily for River yongxing secondary hydropower station dam Foundation curtain grouting, quantities of 200m. Dam Foundation curtain Grouting in dam concrete pouring is complete, reaches a certain intensity, agreed by the supervising engineer and began construction. 11.2 11.2.1 General requirements we are responsible for the procurement of materials, transport, storage, keeping drilling and apart from the employer's manpower required to grout materials for all materials. Admixture, admixture of each procurement shall meet the relevant quality