肺部CT 樹芽征的診斷價值

1、肺部CT 樹芽征的診斷價值,樹芽征(Tree-in-Bud Pattern,樹芽征是指病變累及細(xì)支氣管以下的小氣道，由于小氣道的擴(kuò)張和管腔內(nèi)炎性物質(zhì)的填充，在肺部薄層CT（thin-section computed tomography）或HRCT上表現(xiàn)為直徑2mm4mm的小葉中心軟組織密度結(jié)節(jié)影和與之相連的分支線狀影，狀如樹芽而得名,The tree-in-bud pattern is commonly seen at thin-section computed tomography (CT) of the lungs. It consists of small centrilobular

2、nodules of soft-tissue attenuation connected to multiple branching linear structures of similar caliber that originate from a single stalk,樹芽征,最早由Im等描述為結(jié)核桿菌沿支氣管內(nèi)播散的CT表現(xiàn)， Paslawski等則認(rèn)為樹芽征是細(xì)支氣管炎的典型HRCT征象，其形成基礎(chǔ)是小葉中心支氣管內(nèi)膿液、粘液、肉芽腫或炎性細(xì)胞充填所致。Pipavath等也認(rèn)為樹芽征和小葉中心結(jié)節(jié)為細(xì)支氣管炎的直接征象,病因,本征可見于累及小氣道的多種肺疾病，包括周圍性氣道感染（細(xì)

3、菌、病毒、霉菌或寄生蟲感染）、先天性疾病、特發(fā)性疾病（閉塞性細(xì)支氣管炎、彌漫性泛細(xì)支氣管炎）、吸入性肺炎、毒氣吸入、免疫性疾病、結(jié)締組織病、周圍性肺血管?。ㄈ缒[瘤性栓塞）和腫瘤支氣管內(nèi)轉(zhuǎn)移等 。 樹芽征是由多種影響小氣道的病變所引起的一種非特異性征象,病因,感染（Infection） 先天性病變(Congenital Disorders) 特發(fā)性疾病(Idiopathic Disorders) 異物吸入 毒氣吸入 結(jié)締組織病 免疫性疾病 腫瘤(Neoplasms,一) 感染（Infection,1、細(xì)菌性感染(Bacterial Infection,樹芽征常見于結(jié)核桿菌沿支氣管內(nèi)播散的患者，該

4、征的出現(xiàn)高度提示結(jié)核具有活動性,HRCT表現(xiàn),通常表現(xiàn)為2mm4mm大小的小葉中心結(jié)節(jié)和分支樣線狀影，合并表現(xiàn)有支氣管壁增厚，伴有或不伴有支氣管擴(kuò)張、氣腔實變影、空洞、血行播散所致的邊緣清楚小結(jié)節(jié)影、胸腔積液、淋巴結(jié)腫大（伴有中心壞死）等。Kashyap 等認(rèn)為樹芽征和小葉中心結(jié)節(jié)是支氣管內(nèi)結(jié)核的特征性HRCT表現(xiàn)。 （Kashyap S, Mohapatra PR, Saini V. Endobronchial tuberculosisJ. Indian J Chest Dis Allied Sci. 2003;45(4):247-256.,Postprimary active tuberc

5、ulosis in a 66-year-old woman with a chronic cough. High-resolution CT scans of the right lung show peripheral, poorly defined, small (24-mm-diameter) centrilobular nodules and branching linear opacities of similar caliber originating from a single stalk (the tree-in-bud pattern) in the lower lobe (

6、arrow). These findings represent endobronchial spread of tuberculosis,Postprimary active tuberculosis in a 34-year-old man with weight loss and a chronic cough. (a) High-resolution CT scan of the left lung shows a thick-walled cavity and multiple peripheral small nodules and branching linear structu

7、res (arrows). Note the thickening of the bronchial walls (arrowhead,Photomicrograph (original magnification, x400; hematoxylin-eosin stain) shows impacted caseous material (*) in small peripheral airways (arrow,男性，33歲?？人?、咳痰2月,女性，35歲，咳嗽咳痰午后低熱 1月,男性，34歲，咳嗽發(fā)熱2周,肺部非結(jié)核性分支桿菌（nontuberculous mycobacteria,或稱

8、非典型分枝桿菌（atypical mycobacteria）感染主要由鳥胞內(nèi)分支桿菌(M avium-intracellulare complex,MAIC)和Kansasii分支桿菌致病。 典型放射學(xué)表現(xiàn)類似于繼發(fā)性肺結(jié)核（包括樹芽征在內(nèi),CT表現(xiàn),Jeong等報告1組，其薄層CT掃描最常見表現(xiàn)有雙肺小結(jié)節(jié)（100%）、靜脈曲張型支氣管擴(kuò)張（91%）、樹芽征（77%），相關(guān)的病理組織學(xué)表現(xiàn)為細(xì)支氣管擴(kuò)張、細(xì)支氣管壁增厚、伴有或不伴有肉芽腫的細(xì)支氣管及其周圍炎癥。 -Jeong YJ, Lee KS, Koh WJ, et al. Nontuberculous mycobacterial pu

9、lmonary infection in immunocompetent patients: comparison of thin-section CT and histopathologic findings.RadiologyJ, 2004 ,231(3):880-886,Infection with M avium-intracellulare complex in a 44-year-old woman with malaise and a chronic cough. High-resolution CT scans of the right lung show multiple p

10、eripheral small nodules connected to branching linear opacities and a thick-walled cavity in the superior segment of the lower lobe. Note the thickening of the bronchial walls, bronchial dilatation, and mucus impaction. The diagnosis was confirmed with bronchoalveolar lavage,細(xì)支氣管其他細(xì)菌感染,如金黃色葡萄球菌、流行性嗜

11、血桿菌感染的細(xì)支氣管炎也可表現(xiàn)為周圍分布的樹芽征，其病理學(xué)基礎(chǔ)為細(xì)支氣管壁的炎性細(xì)胞浸潤和管腔內(nèi)炎性滲出物充填所致。 AIDS患者馬紅球菌（Rhodococcus equi）肺部感染CT掃描也可見樹芽征表現(xiàn)。 醫(yī)源性綠膿假單胞菌肺炎(nosocomial Pseudomonas aeruginosa Pneumonia， PAP)有50%患者CT表現(xiàn)有結(jié)節(jié)影，其中1/3可見樹芽征,S aureus bronchiolitis in a 32-year-old man with acquired immunodeficiency syndrome (AIDS). (a) High-resolut

12、ion CT scan shows small peripheral centrilobular nodules and branching linear opacities, resulting in the tree-in-bud pattern,2、霉菌感染(Fungal Infection,氣道侵襲性曲菌病是由曲菌孢子引起的真菌病，臨床常見于免疫妥協(xié)中性粒細(xì)胞減少患者和AIDS患者。主要臨床表現(xiàn)包括急性氣管-支氣管炎、細(xì)支氣管炎和支氣管肺炎，氣管受累者占14%-34,CT表現(xiàn),HRCT表現(xiàn)為支氣管周圍的實變和小葉中心結(jié)節(jié),細(xì)支氣管炎薄層CT掃描的特征性表現(xiàn)為小葉中心結(jié)節(jié)和分支狀線樣影（

13、即樹芽征），其他HRCT表現(xiàn)有肺實變影合并周圍毛玻璃密度影（halo，暈征），因此在免疫妥協(xié)患者或AIDS患者肺部HRCT顯示暈征結(jié)節(jié)和樹芽征可提出肺曲菌病的診斷,Invasive bronchiolar aspergillosis in a patient who underwent bone marrow transplantation. (a) High-resolution CT scan (lung window) shows peripheral branching structures (arrow) associated with focal areas of consolid

14、ation in the right lower lobe,病毒感染（Viral Infection,巨細(xì)胞病毒感染主要見于免疫缺陷患者，臨床癥狀有發(fā)熱、干咳、氣短和低氧血癥。CT表現(xiàn)常無特征性，為散在分布或廣泛分布的磨玻璃密度影、肺實變影及邊緣模糊的結(jié)節(jié)影伴有暈征，少見表現(xiàn)有支氣管血管束增粗和樹芽征。 組織病理學(xué)上小葉中心結(jié)節(jié)為細(xì)支氣管及其周圍有巨噬細(xì)胞、紅細(xì)胞和纖維蛋白聚集所致,呼吸道合胞病毒（RSV）也可引起下呼吸道感染，所致的細(xì)支氣管炎和支氣管肺炎最常見于嬰幼兒和兒童，在成人也可引起肺炎。HRCT表現(xiàn)有磨玻璃密度影、氣腔實變影、支氣管壁增厚和擴(kuò)張以及樹芽征，有時還可見空氣潴留. Ko

15、JP, Shepard JA, Sproule MW, et al. CT manifestations of respiratory syncytial virus infection in lung transplant recipientsJ. J Comput Assist Tomogr, 2000,24(2):235241.,Cytomegalovirus pneumonia in a 51-year-old man with chronic myelogenous leukemia who underwent bone marrow transplantation. (a) Thi

16、n-section CT scan of the right lung shows centrilobular ground-glass opacities in addition to nodules and tree-in-bud opacities (arrow,59-year-old man with adenovirus infection after hematopoietic stem cell transplantation for Hodgkins disease. Transverse thin-section (1-mm collimation, lung window)

17、 CT scan obtained at level of lower pulmonary veins shows branching distal structures (tree-in-bud pattern) (arrow,二)先天性病變(Congenital Disorders,1、囊性纖維化（Cystic fibrosis,囊性纖維化是一種以外分泌腺功能異常、粘液栓形成為特征的常染色體隱性遺傳性多系統(tǒng)疾病，為相對常見的影響上下呼吸道、胰腺、肝臟、膽囊、腸道和生殖道的先天性病變。以外分泌腺功能異常和粘性物的分泌為特征，與水和鹽的細(xì)胞運(yùn)轉(zhuǎn)缺陷有關(guān)，發(fā)生率為1/2000，主要發(fā)生于白種人,

18、CT表現(xiàn),本病的最常見的CT表現(xiàn)為支氣管壁增厚、支氣管周圍間質(zhì)增厚、支氣管擴(kuò)張、細(xì)支氣管擴(kuò)張、指套狀高密度粘液栓影并肺不張或肺實變，盡管典型病例可累及所有肺葉，但病變早期主要累及肺上葉尖后段。樹芽征可能是病變的一個早期征象，這主要是由于細(xì)支氣管內(nèi)有大量的粘性分泌物停留所致。 Oikonomou A, Manavis J, Karagianni P,et al. Loss of FEV1 in cystic fibrosis: correlation with HRCT featuresJ.Eur Radiol, 2002,12(9):2229-2235.,Cystic fibrosis in

19、a 17-year-old boy with a chronic cough. High-resolution CT scan shows dilated thick-walled bronchi and diffuse tree-in-bud patterns (arrow,2、Kartagener 綜合癥,原發(fā)性纖毛運(yùn)動功能障礙綜合癥是包括纖毛功能和結(jié)構(gòu)異常的一組遺傳性疾病，Kartagener 綜合癥是其一個亞型，包括內(nèi)臟轉(zhuǎn)位、鼻竇炎和支氣管擴(kuò)張三聯(lián)癥，支氣管纖毛運(yùn)動異?？蓪?dǎo)致反復(fù)的呼吸道感染和支氣管擴(kuò)張。HRCT表現(xiàn)包括支氣管壁增厚、支氣管擴(kuò)張，氣道損傷延伸到小氣道引起細(xì)支氣管擴(kuò)張、小

20、葉中心結(jié)節(jié)影（樹芽征）和空氣潴留 Rossi SE, Franquet T, Volpacchio M, et al. Tree-in-bud pattern at thin-section CT of the lungs: radiologic-pathologic overviewJ. Radiographics,2005,25(3):789-801.,Kartagener syndrome in a 39-year-old woman with situs inversus, sinusitis, and bronchiectasis. (a) High-resolution CT sc

21、an shows bilateral bronchiectasis (white arrow) and small centrilobular nodules and branching linear opacities in the right lower lobe (black arrow,其他先天性異常,其他多種先天性異常尤其是有支氣管粘膜纖毛清除功能異常、免疫功能缺陷或有支氣管壁結(jié)構(gòu)異常者也可發(fā)生細(xì)支氣管病。例如： Williams-Campbell綜合癥（先天性支氣管軟骨缺陷） Mounier-Kuhn綜合癥（先天性巨氣管支氣管） Bruton氏低丙球蛋白血癥、 IgA 和IgA-I

22、gG缺乏 Yellow nail綜合癥（黃甲綜合癥）20,三）特發(fā)性疾病 (Idiopathic Disorders,1、閉塞性細(xì)支氣管炎（Obliterative Bronchiolitis,閉塞性細(xì)支氣管炎是指細(xì)支氣管粘膜下及其周圍不可復(fù)性纖維化導(dǎo)致的管腔向心性狹窄。盡管本病可見于病毒感染、膠原血管?。ㄈ珙愶L(fēng)濕性關(guān)節(jié)炎尤其是用青霉胺或金鹽治療后）、毒氣吸入和臟器移植（肺或骨髓移植）等，但大部分為特發(fā)性的,臨床表現(xiàn),患者常有進(jìn)行性呼吸困難和氣道阻塞的功能檢查異常。本病的診斷標(biāo)準(zhǔn)為無肺氣腫、慢性支氣管炎、哮喘及其他原因氣道阻塞的患者有不可復(fù)性氣流受限，F(xiàn)EV1小于60%等,影像學(xué)表現(xiàn),胸部X

23、線片表現(xiàn)肺血減少、肺葉過度膨脹。 HRCT表現(xiàn)有中央性和周圍性支氣管擴(kuò)張、支氣管壁增厚，呼吸末HRCT掃描有空氣潴留是發(fā)現(xiàn)閉塞性細(xì)支氣管炎的最敏感征象，此外粘液嵌塞引起的小葉中心結(jié)節(jié)和樹芽征也可見,Obliterative bronchiolitis after bone marrow transplantation in a 47-year-old man with myeloma. (a) Expiratory high-resolution CT scan shows diffuse centrilobular nodules connected to branching linear

24、opacities bilaterally. Note the air trapping in the right lower lobe,2、彌漫性泛細(xì)支氣管炎(Diffuse Panbronchiolitis,DPB,彌漫性泛細(xì)支氣管炎是一種幾乎僅發(fā)生于亞洲人的進(jìn)行性肺部炎癥性病變，其原因不明，特征性病理改變是副鼻竇和呼吸性細(xì)支氣管的慢性炎癥，呼吸性細(xì)支氣管壁增厚，管壁全層有淋巴細(xì)胞、漿細(xì)胞和組織細(xì)胞浸潤，病變進(jìn)展可形成細(xì)支氣管擴(kuò)張。大部分患者為非吸煙者且?guī)缀醵加新员歉]炎,CT表現(xiàn),HRCT表現(xiàn)有小的小葉中心結(jié)節(jié)（5mm）、小葉中心結(jié)節(jié)與分支樣線狀影相連即樹芽征，此外可見支氣管壁增厚、支氣

25、管擴(kuò)張，病變主要累及肺的基底部，病變晚期可見囊性病變和空氣潴留,Diffuse panbronchiolitis in a 44-year-old Japanese man. High-resolution CT scan shows diffuse small centrilobular nodules and branching linear opacities (arrow), which resemble the objects used in the game of jacks. Note the bronchiolar dilatation and mucoid impaction

26、 (arrowheads,四）異物吸入,病因,彌漫性吸入性細(xì)支氣管炎是由于異物顆粒反復(fù)多次吸入細(xì)支氣管所引起的慢性炎癥。造成因素有咽部結(jié)構(gòu)異常、食道病變（賁門失弛緩癥、食道裂孔疝、食道癌）、神經(jīng)系統(tǒng)病變以及慢性疾病等,影像學(xué)表現(xiàn),無特征，可見肺葉、肺段或彌漫性分布的1mm3mm的小陰影，HRCT表現(xiàn)有小葉中心結(jié)節(jié)、單側(cè)或雙側(cè)分支狀高密度病灶及樹芽征，病灶的分布取決于吸入物在細(xì)支氣管的位置。 Franquet T, Gimenez A, Roson N,et al.Aspiration diseases: findings, pitfalls, and differential diagnosi

27、sJ. RadioGraphics, 2000,20(3):673685.,Diffuse aspiration bronchiolitis in a 61-year-old woman with achalasia（賁門失遲癥） who experienced recurrent aspiration of foreign particles. Thin-section CT scan shows multiple centrilobular areas of increased attenuation with a characteristic tree-in-bud appearance

28、. Esophageal dilatation with an air-fluid level is also seen,五）毒氣吸入,毒氣或有毒的煙塵吸入可導(dǎo)致急慢性肺部損害。病理主要表現(xiàn)為肺泡毛細(xì)血管的損傷、肺水腫、支氣管炎和細(xì)支氣管炎，有時并發(fā)肺不張和肺炎，病變后期可見閉塞性細(xì)支氣管炎。HRCT可見支氣管壁增厚、雙肺實變影、支氣管擴(kuò)張和樹芽征,Inhalation bronchiolitis in a 56-year-old man after accidental exposure to sulfur dioxide. High-resolution CT scan shows bro

29、nchiectasis in combination with the tree-in-bud pattern in the right lower lobe,六）結(jié)締組織病,類風(fēng)濕性關(guān)節(jié)炎和干燥綜合癥可影響小氣道，最常見的胸部表現(xiàn)是囊狀支氣管炎、支氣管擴(kuò)張、細(xì)支氣管炎、閉塞性細(xì)支氣管炎和機(jī)化性肺炎。 Perez T, Remy Jardin M, Cortet B. Airways involvement in rheumatoid arthritis: clinical, functional, and HRCT findingsJ. Am J Respir Crit Care Med,1

30、998,157(5):16581665.,干燥綜合癥可合并淋巴細(xì)胞性間質(zhì)性肺炎，薄層CT表現(xiàn)可見支氣管擴(kuò)張、邊緣模糊的小葉中心結(jié)節(jié)和分支線狀影（樹芽征）。此外可有磨玻璃密度影、空氣潴留和蜂窩。 Lohrmann C, Uhl M, Warnatz K,et al. High-resolution CT imaging of the lung for patients with primary Sjogrens syndromeJ.Eur J Radiol,2004,52(2):137-143.,Sjgren syndrome in a 54-year-old woman. Thin-secti

31、on CT scan shows peripheral tree-in-bud patterns in the right lower lobe. Note the bronchial dilatation, bronchial wall thickening, and consolidation,七）免疫性疾病,病因與病理,過敏性支氣管肺曲菌病是由于支氣管內(nèi)增殖的曲菌菌絲引起的I型和III型（IgE 和IgG）免疫反應(yīng)，免疫復(fù)合物和炎性細(xì)胞沉積于支氣管粘膜導(dǎo)致支氣管粘膜壞死和嗜酸細(xì)胞浸潤，支氣管壁受損繼發(fā)支氣管擴(kuò)張，過敏反應(yīng)引起支氣管分泌物增加，與繁殖的菌絲混合使得分泌物粘性增加不易咳出引起

32、粘液嵌塞。過敏性支氣管肺曲菌病最常見于囊性纖維化和支氣管哮喘患者,影像學(xué)表現(xiàn),本病的典型放射學(xué)表現(xiàn)是以肺上葉分布為主的支氣管擴(kuò)張和粘液嵌塞，粘液嵌塞表現(xiàn)為密度均勻的管狀或“手套狀”致密影，粘液嵌塞可向細(xì)支氣管延伸產(chǎn)生樹芽征。 Gotway MB, Dawn SK, Caoili EM, et al. The radiologic spectrum of pulmonary Aspergillus infectionsJ. J Comput Assist Tomogr, 2002,26(2):159173.,Allergic bronchopulmonary aspergillosis in a

33、 36-year-old man with a history of asthma. High-resolution CT scans show peripheral mild bronchiolar dilatation and mucoid impaction in the anterior segment of the left upper lobe (long arrow) and the posterior segment of the right upper lobe, resulting in the tree-in-bud pattern. Note the bronchial

34、 wall thickening (short arrow,八）腫瘤 (Neoplasms,據(jù)尸體解剖發(fā)現(xiàn)肺血管內(nèi)腫瘤栓子的發(fā)生率為2.4%-26%，常見的引起肺血管腫瘤栓子的肺外原發(fā)性惡性腫瘤有乳腺癌、肝癌、腎癌、胃癌、前列腺癌和卵巢癌。 Rossi SE, Goodman PC, Franquet T. Nonthrombotic pulmonary emboli: reviewJ. AJR Am J Roentgenol 2000; 174(6):14991508,影像學(xué)表現(xiàn),薄層CT可顯示多處血管擴(kuò)張或串珠狀影、周圍性楔形影、小葉內(nèi)間隔增厚、小葉中心結(jié)節(jié)和樹芽征。腫瘤的支氣管內(nèi)轉(zhuǎn)移累及

35、小氣管也可表現(xiàn)為呈樹芽征的小葉中心結(jié)節(jié)影，近期Kao29 等報告了1例胸腺癌支氣管內(nèi)轉(zhuǎn)移在HRCT上就主要表現(xiàn)為樹芽征。 Tack D, Nollevaux MC, Gevenois PA,et al. Tree-in-bud pattern in neoplastic pulmonary emboliJ.AJR Am J Roentgenol, 2001,176(6):1421-1422,Tumor emboli from Ewing sarcoma in a 16-year-old boy. High-resolution CT scan shows enlarged and beaded