Pituitary gland, also called hypophysis, ductless gland of the endocrine system that secretes hormones directly into the bloodstream. The term hypophysis (from the Greek for 「lying under」)—another name for the pituitary—refers to the gland’s position on the underside of the brain. The pituitary gland is called the 「master gland」 because its hormones regulate other important endocrine glands—including the adrenal, thyroid, and reproductive glands (e.g., ovaries and testes)—and in some cases have direct regulatory effects in major tissues, such as those of the musculoskeletal system.
垂體，又稱腦垂體，內分泌系統中無導管的腺體，直接向血液中分泌激素。垂體這個詞（來自希臘語，意為「躺在下面」）——垂體的另一個名稱是指腺體在大腦底部的位置。垂體被稱為「主腺」，因為它的激素調節其他重要的內分泌腺，包括腎上腺、甲狀腺和生殖腺（如卵巢和睪丸），在某些情況下，它對主要組織（如肌肉骨骼系統）有直接的調節作用。
The pituitary gland lies at the middle of the base of the skull and is housed within a bony structure called the sella turcica, which is behind the nose and immediately beneath the hypothalamus. The pituitary gland is attached to the hypothalamus by a stalk composed of neuronal axons and the so-called hypophyseal-portal veins. Its weight in normal adult humans ranges from about 500 to 900 mg (0.02 to 0.03 ounce).
垂體位於顱底的中部，位於一個叫做蝶鞍的骨質結構內，蝶鞍位於鼻子後面，緊接著在下丘腦下面。垂體通過一個由神經元軸突和所謂的垂體門靜脈組成的柄與下丘腦相連。它在正常成人中的重量約為500到900毫克（0.02到0.03盎司）。
In most species the pituitary gland is divided into three lobes: the anterior lobe, the intermediate lobe, and the posterior lobe (also called the neurohypophysis or pars nervosa). In humans the intermediate lobe does not exist as a distinct anatomic structure but rather remains only as cells dispersed within the anterior lobe. Nonetheless, the anterior and posterior lobes of the pituitary are functionally, anatomically, and embryologically distinct. Whereas the anterior pituitary contains abundant hormone-secreting epithelial cells, the posterior pituitary is composed largely of unmyelinated (lacking a sheath of fatty insulation) secretory neurons.
在大多數物種中，垂體被分成三個葉：前葉、中間葉和後葉（也稱為神經垂體或神經部）。在人類中，中間葉不作為一個明顯的解剖結構存在，而只作為分散在前葉內的細胞存在。儘管如此，垂體的前葉和後葉在功能上、解剖上和胚胎上是不同的。垂體前葉含有大量分泌激素的上皮細胞，而垂體後葉則主要由無髓（缺乏脂肪絕緣鞘）分泌神經元組成。
The pituitary gland is a dual-supplying organ, similarly: the liver: the hepatic and portal veins; the lungs: the pulmonary and bronchial arteries; the brain: the internal carotid and vertebral arteries; the adrenal: the adrenal arteries and renal arteries.
垂體是雙重供血器官，類似的還有：肝臟：肝動脈和門靜脈供血；肺：肺動脈和支氣管動脈；腦：頸內動脈系統和椎動脈系統；腎上腺：腎上腺動脈和腎動脈。
The blood supply to the pituitary gland is complicated. The pituitary artery first descends through the pituitary funnel to reach the anterior pituitary gland to form the pituitary portal system. "The normal anterior pituitary gland passes through the pituitary portal system and indirectly supplies its blood from the pituitary arteries. The blood supply to the posterior pituitary is directly from the neck The branch of the internal artery. Therefore, during dynamic enhancement, the posterior lobe and the funnel are strengthened at the earliest stage. Because the anterior pituitary is indirectly supplied with blood through the pituitary portal system, it is slower than the posterior lobe during dynamic enhancement. The enhancement is later than the above. The blood supply of pituitary microadenomas is also different. It is generally believed that the blood supply is from the pituitary portal system, probably due to the slow blood flow in the tumor. "The peak of microadenoma enhancement is slower than normal pituitary , Showing a low signal. However, there is evidence that a small number of pituitary microadenomas are directly supplied by the internal carotid artery, so,In the early stage of dynamic enhancement, it showed a high signal ". Therefore, in the early stage of dynamic enhancement, the diagnosis of pituitary microadenomas is the most effective. In order to better display the pituitary microadenomas, the imaging time is generally within 2 minutes.
垂體的血供比較複雜。上下垂體動脈首先通過垂體漏鬥部下降到達垂體前葉形成垂體門脈系統"。正常垂體前葉通過垂體門脈系統,由上下垂體動脈來間接供給其血液。垂體後葉的血液供應直接來源於頸內動脈的分支。因此,動態增強時,最早期是後葉及漏鬥部強化,垂體前葉由於是通過垂體門脈系統間接供血的,所以在動態增強時比後葉強化慢。垂體周邊部的強化更晚於上述部位。垂體微腺瘤的血供也有不同。一般認為是由垂體門脈系統供血,大概由於腫瘤內的血流緩慢的緣故",微腺瘤增強的高峰比正常垂體要慢,表現為低信號。但有證據表明少數垂體微腺瘤由頸內動脈直接供血,所以在動態增強早期強化,表現為高信號」。因此,在動態增強早期的影像對垂體微腺瘤的診斷是最有效的。為了更好地顯示垂體微腺瘤,造影時間一般要在2分鐘以內。
Scanning plan of pituitary gland 垂體的掃描方案
1. Locate the coronal plane in the sagittal plane image, the positioning line is parallel to the pituitary stalk, adjust the angle in the cross section, and adjust the left and right and up and down positions of the FOV in the coronal plane to make the image center symmetrical.
2. Conventionally adopt 140-180mmFOV, RL phase coding, 9-12 layers (including full pituitary and saddle structure), layer thickness / spacing: 3mm / 0.3mm, if the lesion penetrates can increase the layer thickness or number of layers
3. T1WI COR sequence can add parallel saturation bands before and after respectively, the purpose is to reduce vascular pulse artifacts.
1.在矢狀面圖像定位冠狀面，定位線平行於垂體柄，橫斷面調整角度，在冠狀面上調整FOV左右與上下的位置，使圖像居中對稱；
2.常規採用140-180mmFOV，RL相位編碼，9-12層（包全垂體及鞍旁結構），層厚/間距：3mm / 0.3mm，如病灶穿透可增加層厚或層數；
3. T1WI COR序列可分別在前後分別加平行飽和帶，目的是減少血管搏動偽影。
4. Using SE sequence scan, in order to ensure the display of small lesions in the pituitary, TSE technology is generally not recommended;
5. Thin-field scanning with small field of view to ensure good observation of pituitary structure;
6. The diagnosis of pituitary mainly depends on T1WI.
4. 採用SE序列掃描，為保證垂體內微小病變顯示，通常不建議使用TSE技術;
5. 採用小視野薄層掃描，保證垂體結構得到良好觀察;
6.垂體的診斷主要依賴T1WI。
The normal pituitary has no blood-brain barrier, and the enhancement can occur in the early stage after the injection of contrast agent, while most microadenomas are supplied by the portal system of the pituitary, and the enhancement is slower than that of the normal pituitary. In the early stage after the injection of contrast agent, the enhancement is weak or not, and the delayed stage is stronger than that of the normal pituitary.
正常的垂體無血-腦屏障,在注射造影劑後的早期即可發生強化,而大多數的微腺瘤由垂體的門脈系統供血,其強化比正常垂體慢,在注射造影劑後早期表現為弱強化或不強化,延遲期較正常垂體強化。
Most literatures in the industry indicate that the full-contrast angiography scan (0.1mmol / kg) will reduce the contrast between normal pituitary and progressively enhanced pituitary microadenomas, so it is recommended to use half-dose (0.05mmol / kg) angiography scan for dynamic enhancement scanning.Half dose dynamic contrast-enhanced scan and delayed contrast-enhanced scan have high application value in the diagnosis of pituitary microadenoma, which can be used as a routine imaging method for the diagnosis of pituitary microadenoma.
業內多數文獻表明：全計量造影掃描方式（0.1mmol/kg）會降低正常垂體與逐漸強化的垂體微腺瘤之間的對比度，故推薦使用半劑量（0.05mmol/kg）造影掃描方式進行動態增強掃描。半劑量動態對比增強掃描和延遲對比增強掃描在垂體微腺瘤的診斷中具有較高的應用價值，可作為常規的影像學方法診斷垂體微腺瘤。
After a few days, we will similarly recommend a cardiac magnetic resonance scanning protocol to you. Please light up "Looking" to let more people know about us.
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