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. 3, 淋巴管瘤 腎上腺囊性的淋巴管瘤罕見,沒有癥狀。 Figure 7. (a, b) Coronal T1weighted inphase and T2weighted halfFourier RARE MR images show an oval, wellcircumscribed, right adrenal cyst (arrow in b) with a thin wall (arrowhead in b). The cyst has a typical appearance, showing low signal intensity at T1weighted imaging and high signal intensity at T2weighted imaging. Photomicrograph (original magnification, 100。囊腫出血,破裂或感染時出現(xiàn)急性癥狀。巨大髓樣脂肪瘤要和腹膜后像脂肪肉瘤鑒別。 髓樣脂肪瘤根據(jù) MR信號特征分為三類: 1)以脂肪成分為主型: T1WI均勻高信號, T2WI中等信號。 Figure 5. Axial T1weighted outofphase MR image shows an adrenal adenoma (black arrow) with a focal area of highsignalintensity hemorrhage (white arrow). 2,髓樣脂肪瘤 髓樣脂肪瘤是不常見的良性腫瘤。 Figure 4. (a, b) Axial inphase and outofphase MR images show an adrenal adenoma (arrow), which exhibits the typical decrease in signal intensity on the outof phase image. Photograph of the specimen shows a wellcircumscribed bright yellow nodule, an appearance that is typical of adrenocortical adenoma. 增強時均勻一致強化也是腎上腺腺瘤的特征,腎上腺腺瘤小的,圓點狀信號強度改變可能是由于囊變,出血或血供的差異。在化學位移成像上信號減低能夠 在脂 —水交界處發(fā)現(xiàn),腫塊邊緣具有代表性。 it has a triangular, inverted Y, or V configuration. Normal adrenal glands range from 2 to 6 mm in thickness and from 2 to 4 cm in length. Figure 3. Coronal T1weighted, threedimensional, GRE MR image obtained with VIBE shows the normal inverted Y shape of the right adrenal gland (arrow 三 MRI檢查技術: 腎上腺成像最重要的是化學位移成像,可以通過擾相 GRE的 inphase and outofphase來完成。 hematoxylineosin [HE] stain) of a normal adrenal gland specimen shows an outer capsule (C) and the cortical layers: zona glomerulosa (G), fasciculata (F), and reticularis (R). The medulla (M) is present centrally. 二,正常腎上腺 MRI表現(xiàn): 在軸位及冠狀位 MRI圖像上,右側腎上腺直接位于下腔靜脈后方,右腎上極上方,呈線狀,倒 V或 Y形。 腎上腺的血管分布:腎上腺上面有膈下動脈的終末分支,經(jīng)腎上腺靜脈出腎上腺。 腎上腺實質由周邊的皮質和中央的髓質兩部分構成,兩者在發(fā)生、結構和功能上均不相 同,皮質來自中胚層,髓質來自外胚層。這些特征可用于大部分腎上腺占位:腺瘤,增生,單純或復雜囊腫,淋巴管瘤,髓樣脂肪瘤,嗜鉻細胞瘤 ,腎上腺出血,皮質腺癌,神經(jīng)母細胞瘤,淋巴瘤和轉移瘤。 一,組織學及解剖學 腎上腺位于腎的上方,右側腎上腺呈人字形,左側呈半月形,右側較左側稍高。 皮質約占腎上腺體積的 80%~ 90%,根據(jù)皮質細胞的形態(tài)結構