正常胸腺及胸腺病变CT表现吕晓飞
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CT及MR在胸腺异常的诊断中有重要作用， 有利于评价是否正常及胸腺病变的范围。
2 正常胸腺的CT表现
胚胎发育 正常胸腺解剖位置及异位胸腺 正常CT表现（形态、大小、密度）
胚胎发育
胎儿第6周，胸腺起源于第三及第四咽囊； 第7周，胸腺始基延长并呈圆柱状形态，形
成胸腺咽管，逐渐移行至前纵隔； 第8周，胸腺始基于下极融合； 第10周，肝脏组织及骨髓内的小淋巴样细胞
异位胸腺
A
B
Figure 1. Normal thymus with a cervical component in a 12-year-old boy. (a) Sagittal ultrasonographic (US) image shows the mediastinal and cervical components of the thymus (black arrows) attached to the lower pole of the thyroid (white arrow) via the thyrothymic ligament (arrowhead). Note the “starry sky” appearance of the thymus; this is created by hyperechoic fat against the background of the remaining hypoechoic lymphoid tissue. (b) Corresponding anatomic drawing shows the mediastinal (arrowheads) and cervical (arrows) components of the thymus.
正常CT表现（形态）
9岁以下多呈方形或梯形，10岁以后 随年龄变化较大。
正常CT表现（大小）
胸腺的形态随年龄而异，年轻人（特别是25岁以下者）的正常胸腺的大小和 重量有较大的差异。
国内研究学者认为胸腺的厚度随年龄变化，变化最大是在20-49岁之间，总 体来说是从大到小再到大，大于60岁有增大趋势；<59岁，均小于21mm； >60岁，可超过30mm。宽度则随年龄增大而增大。
正常胸腺及胸腺病变
—CT表现
The Normal and Abnormal Thymus —— CT imaging finding
南方医院影像中心 2009级博士研究生
吕晓飞
Content
1
概述
2 正常胸腺的CT表现
3 胸腺病变的CT表现
1
概述百度文库
胸腺是一种复杂的淋巴上皮器官，具有调节细 胞免疫的功能，在人类正常免疫中是不可缺少 的。
正常胸腺解剖
A
B
异位胸腺
Ectopic and accessory thymic tissue may occur anywhere along the path of descent (thymopharyngeal duct) as the result of failure of descent, sequestration, or failure to involute. Ectopic or accessory thymic tissue may be found in the vicinity of the superior vena cava, brachiocephalic vessels, and aorta. Rarely, it may be found in the posterior mediastinum or even in the dermis .
异位胸腺
Figure 3. Ectopic parapharyngeal thymus in a 7-week-old boy with a “mass” in the right mandib-ular angle. Coronal contrast material–enhanced T1-weighted magnetic resonance (MR) image shows an enhancing parapharyngeal mass (arrow), which is isointense relative to the mediastinal thymus (arrowhead). At needle biopsy, the mass was proved to be ectopic thymic tissue.
异位胸腺
A
B
Figure 2. Cervical component of the thymus in a 3-year-old boy with a strong maternal family history of papillary thyroid carcinoma. The cervical component was misinterpreted as an “exophytic tumor of the thyroid gland.” Contrast-enhanced CT scans show a normal mediastinal thymus (arrows in A) and its cervical component (arrows in B). Follow-up studies 2 years later showed no change, and the patient remained asymptomatic.
移行至胸腺始基； 第14~16周，胸腺进一步分化形成皮质及髓
质成分。
正常胸腺解剖位置
位于前上纵隔，上达胸廓入口 （甚至突入颈部接近甲状腺下 缘），下至心包前面上部，两侧 临近纵隔胸膜，后面贴附心包及 左头臂静脉及主动脉弓。
胸腺的位置上界不超过胸骨柄 上缘，下缘不超过左心室上缘或 主动脉根部层面，外缘不超过上 腔静脉、主动弥弓外缘．其前缘 位置正常可随周围结构改变而向 左或向右移位。
2 正常胸腺的CT表现
胚胎发育 正常胸腺解剖位置及异位胸腺 正常CT表现（形态、大小、密度）
胚胎发育
胎儿第6周，胸腺起源于第三及第四咽囊； 第7周，胸腺始基延长并呈圆柱状形态，形
成胸腺咽管，逐渐移行至前纵隔； 第8周，胸腺始基于下极融合； 第10周，肝脏组织及骨髓内的小淋巴样细胞
异位胸腺
A
B
Figure 1. Normal thymus with a cervical component in a 12-year-old boy. (a) Sagittal ultrasonographic (US) image shows the mediastinal and cervical components of the thymus (black arrows) attached to the lower pole of the thyroid (white arrow) via the thyrothymic ligament (arrowhead). Note the “starry sky” appearance of the thymus; this is created by hyperechoic fat against the background of the remaining hypoechoic lymphoid tissue. (b) Corresponding anatomic drawing shows the mediastinal (arrowheads) and cervical (arrows) components of the thymus.
正常CT表现（形态）
9岁以下多呈方形或梯形，10岁以后 随年龄变化较大。
正常CT表现（大小）
胸腺的形态随年龄而异，年轻人（特别是25岁以下者）的正常胸腺的大小和 重量有较大的差异。
国内研究学者认为胸腺的厚度随年龄变化，变化最大是在20-49岁之间，总 体来说是从大到小再到大，大于60岁有增大趋势；<59岁，均小于21mm； >60岁，可超过30mm。宽度则随年龄增大而增大。
正常胸腺及胸腺病变
—CT表现
The Normal and Abnormal Thymus —— CT imaging finding
南方医院影像中心 2009级博士研究生
吕晓飞
Content
1
概述
2 正常胸腺的CT表现
3 胸腺病变的CT表现
1
概述百度文库
胸腺是一种复杂的淋巴上皮器官，具有调节细 胞免疫的功能，在人类正常免疫中是不可缺少 的。
正常胸腺解剖
A
B
异位胸腺
Ectopic and accessory thymic tissue may occur anywhere along the path of descent (thymopharyngeal duct) as the result of failure of descent, sequestration, or failure to involute. Ectopic or accessory thymic tissue may be found in the vicinity of the superior vena cava, brachiocephalic vessels, and aorta. Rarely, it may be found in the posterior mediastinum or even in the dermis .
异位胸腺
Figure 3. Ectopic parapharyngeal thymus in a 7-week-old boy with a “mass” in the right mandib-ular angle. Coronal contrast material–enhanced T1-weighted magnetic resonance (MR) image shows an enhancing parapharyngeal mass (arrow), which is isointense relative to the mediastinal thymus (arrowhead). At needle biopsy, the mass was proved to be ectopic thymic tissue.
异位胸腺
A
B
Figure 2. Cervical component of the thymus in a 3-year-old boy with a strong maternal family history of papillary thyroid carcinoma. The cervical component was misinterpreted as an “exophytic tumor of the thyroid gland.” Contrast-enhanced CT scans show a normal mediastinal thymus (arrows in A) and its cervical component (arrows in B). Follow-up studies 2 years later showed no change, and the patient remained asymptomatic.
移行至胸腺始基； 第14~16周，胸腺进一步分化形成皮质及髓
质成分。
正常胸腺解剖位置
位于前上纵隔，上达胸廓入口 （甚至突入颈部接近甲状腺下 缘），下至心包前面上部，两侧 临近纵隔胸膜，后面贴附心包及 左头臂静脉及主动脉弓。
胸腺的位置上界不超过胸骨柄 上缘，下缘不超过左心室上缘或 主动脉根部层面，外缘不超过上 腔静脉、主动弥弓外缘．其前缘 位置正常可随周围结构改变而向 左或向右移位。