腎上腺腫塊mr的特征及診斷-預(yù)覽頁
【正文】 分類 。成人的每側(cè)腎上腺重 4～ 5g。 髓質(zhì)主要由排列成索或團(tuán)的髓質(zhì)細(xì)胞組成，髓質(zhì)細(xì)胞又稱為嗜鉻細(xì)胞 (chromaffin cell)。髓質(zhì)內(nèi)的小靜脈匯合成一條中央靜脈，最后匯入腎上腺靜脈，右側(cè)直接引入下腔靜脈，左側(cè)先與膈下靜脈會(huì)合，爾后引入左腎靜脈。正常腎上腺 26mm厚， 24 cm長。 四：含脂肪腎上腺腫塊 Fatcontaining Adrenal Masses Fatcontaining adrenal masses can be classified into two main types: those that contain intracellular fat (eg, adenoma) and those with macroscopic fat (eg, myelolipoma). Adrenal masses that contain intracellular fat have been shown to lose signal intensity on chemical shift outofphase images pared with inphase images owing to the presence of intracellular lipid. Adrenal lesions that contain macroscopic fat demonstrate a loss of signal intensity on fatsaturated images. A loss of signal intensity at chemical shift imaging can be seen at fatwater interfaces, typically at the borders of such lesions 含脂肪腎上腺腫塊分為兩類：細(xì)胞內(nèi)脂質(zhì)（如腺瘤），肉眼可見脂肪 （如髓樣脂肪瘤）。腎上腺腺瘤最重要的特征是細(xì)胞內(nèi)脂質(zhì)，化學(xué)位移成像是腎上腺腺瘤最可靠的檢查手段。亞急性期， T1WI高信號， T2WI開始低信號，隨后呈高信號。大部分是在偶然時(shí)發(fā)現(xiàn)。 3)髓樣成分為主型：相對于肝臟， T1WI低信號， T2WI高信號，增強(qiáng)有強(qiáng)化。 HE stain) shows the typical microscopic appearance of myelolipoma. There is fat and a maturing marrow element on the right side and an otherwise normal adrenal cortex on the left. 五，囊性腫塊 腎上腺囊腫罕見，經(jīng)常是偶然發(fā)現(xiàn)或尸檢發(fā)現(xiàn)，尸檢發(fā)病率約%~% 。占腎上腺囊腫約 40%。占腎上腺囊腫約 39% 。 表現(xiàn)為具有薄壁的 T1WI低信號 T2WI高信號，沒有軟組織成分，沒有強(qiáng)化。 嗜鉻細(xì)胞瘤也被稱為“ 10%腫瘤”。腎上腺皮質(zhì)增生信號和正常腎上腺相近，在 outofphase上信號減低（尤其是在呈腺瘤樣結(jié)節(jié)患者上）。 Figure 13. Axial unenhanced T1weighted threedimensional GRE MR image obtained with VIBE demonstrates a right adrenal gland with a highsignalintensity rim (arrows), a finding that is consistent with subacute hematoma. 八，惡性腫瘤 1，腎上腺皮質(zhì)腺癌 原發(fā)腎上腺皮質(zhì)腺癌十分罕見，發(fā)病率約百萬分之二。壞死能夠引起 T2WI高信號。腎上腺淋巴瘤 T1WI上低信號和 T2WI上不均勻高信號。 一般為雙側(cè)，也可單側(cè)。 Figure 16. (a, b) Axial T2weighted MR image obtained with inversion recovery and contrastenhanced T1weighted MR image obtained with VIBE show metastasis from renal cell carcinoma, which has a central area of necrosis. 九，兒科腫瘤 神經(jīng)母細(xì)胞瘤是小兒最常見的顱外實(shí)性腫瘤，其他腎上腺腫瘤，如：嗜鉻細(xì)胞瘤 ,皮質(zhì)腺癌，淋巴瘤十分罕見。 神經(jīng)母細(xì)胞瘤臨床一般無癥狀，除非侵犯或壓迫臨近組織，轉(zhuǎn)移或其他。出血區(qū)域引起 T1WI高信號。和神經(jīng)母細(xì)胞瘤一樣，起源于神經(jīng)脊
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