文献学习：《泪道断层影像综述：影像科医生需要了解的知识》

《泪道断层影像综述：影像科医生需要了解的知识》译者：胡健。著作权/版权归原作者/出版社所有。原文发表于2019年。译者注：“nasolacrimal drainage apparatus”直译为“鼻泪引流器”，根据本文内容和译者习惯，将其译为“泪道系统”或“泪道”。OBJECTIVE.The purpose of this study is toprovide a comprehensive review of the radiographic anatomy and cross-sectionalimaging findings of the full gamut of nasolacrimal drainage apparatus diseases,highlighting imaging findings from the different nasolacrimal drainageapparatus surgeries, posttreatment complications, and potential imagingpitfalls.目的. 本文目的是全面回顾各种泪道疾病的放射影像学解剖和断层图像表现，着重介绍不同泪道系统手术、术后并发症的影像学表现和潜在的影像陷阱。CONCLUSION. Radiologists play a criticalrole in guiding the management of nasolacrimal drainage apparatus diseases andshould be familiar with the anatomy and characteristic imaging findings ofcommonly encountered nasolacrimal drainage apparatus abnormalities andsurgeries.结论。影像医生在指导泪道系统疾病的治疗中起着至关重要的作用，他们应熟悉常见的泪道系统疾病和手术的解剖学和影像学特征。（正文）Nasolacrimal drainage apparatus abnormalities presenting withepiphora, punctual discharge, or medial canthal swelling are common ophthalmic complaintsaccounting for approximately 3% of ophthalmologic clinic visits in some series[1, 2]. Although many nasolacrimal drainage apparatus diseases are diagnosedclinically, imaging can be helpful to assess for causative factors, document theanatomy, or visualize adjacent tissue [3]. Although there is a plethora of ear,nose, and throat and ophthalmologic literature about nasolacrimal drainageapparatus abnormalities, only scant radiology literature addresses the nasolacrimaldrainage apparatus region [4–6]. The purpose of the present article is toprovide radiologists with an up-to-date comprehensive review of thecross-sectional imaging of the anatomy of the nasolacrimal drainage apparatusas well as its abnormalities, surgical considerations, complications, andimaging pitfalls, thereby allowing more accurate and better communicationbetween radiologists and clinicians.泪道疾病表现为溢泪、泪点分泌物或内眦肿，是常见眼科主诉，据报道约占所有眼科门诊患者的3%。一些泪道疾病是临床诊断，但影像学有助于评估病因，记录解剖或观察相邻组织。虽然关于泪道疾病的耳鼻喉和眼科文献有很多，但泪道疾病的影像学文献很少。本文目的是为影像科医生提供泪道解剖及泪道疾病、手术相关、并发症的断层图像和影像学陷阱的最新进展，使得影像医生与临床医生能够更准确、更好地交流。Radiologic Anatomy of theNasolacrimal Drainage Apparatus泪道系统的放射影像学解剖Tears are secreted by the lacrimal glands at the superolateralaspects of the orbits [7] and then are mixed with mucous secretions of theconjunctival and eyelid glands, including the meibomian glands, making tearsoily to resist evaporation. The upper and lower eyelids act as wipers to spreadthe tear film across the globe [8]. This blinking action acts to push the tearstoward the lacrimal lake at the medial canthus. Tears are principally removedby drainage through the puncta after each blink and by evaporation from theopen eye. As the lids open, a drop in canalicular pressure occurs and fluid issucked into the puncta from the lacrimal lake [8]. Tears then drain through thesuperior and inferior canaliculi, common canaliculus, Rosenmüller valve, lacrimalsac, and nasolacrimal duct, finally emptying through the Hasner valve into theinferior meatus. The Hasner valve is a functional barrier to retrograde flow orreflux of fluid [3–5, 9] (Fig. 1A).泪由泪腺分泌，泪腺位于外上眶部；泪液中的黏液成分由结膜和眼睑腺体分泌；脂性成分由meibomian腺分泌，能够减少泪液蒸发。上睑和下睑像刷子一样将泪膜分布于眼表。瞬目动作将泪推向内眦的泪湖。每次瞬目，泪经泪点引流，或经眼表蒸发。眼睑睁开时，泪小管内压减小，液体经泪湖被吸入泪点。然后经上下泪小管、泪总管、Rosenmüller瓣、泪囊、鼻泪管引流，最终经Hasner瓣排至下泪道。Hasner瓣是防止液体逆流的功能性屏障（图1A）。On cross-sectionalimaging, the lacrimal sac lies in the bony lacrimal fossa formed by theanterior lacrimal crest of the frontal process of the maxillary bone and theposterior lacrimal crest of the lacrimal bone. It is normal for the lacrimalsac and duct to be either fluid (tear) filled or air filled (Fig. 1B). Thelacrimal sac is a preseptal structure because the anterior and posterior slipsof orbicularis oculi muscle invest the sac as it attaches to the lacrimalcrests; thus, lacrimal sac infections preferentially spread in the preseptalspace [3, 4] (Fig. 1B, inset). The nasolacrimal duct has intraosseous andmembranous parts and generally slopes posteriorly as it ends below the inferiorturbinate. The lacrimal sac and duct are surrounded by lacrimal fascia and richvenous plexuses, which directly communicate with the nasal mucosal venous plexuses;thus, edema within the nasal mucosa may lead to venous plexus engorgement andsubsequent compression of the nasolacrimal duct [3].在断层影像上，泪囊位于泪囊窝内，泪囊窝由泪前嵴（上颌骨额突）和泪后嵴（泪骨）形成。正常情况下泪囊和鼻泪管内由液体（泪）或空气填充（图1B）。泪囊是眶隔前结构，因为眼轮匝肌前支和后支包裹泪囊，然后附着于泪嵴；因此泪囊感染首先在眶隔前间隙扩散（图1B，插图）。鼻泪管兼具骨内部分和膜性部分，一般向后倾斜，然后终止于下鼻甲下方。泪囊和鼻泪管被泪筋膜和丰富的静脉丛包绕，后者与鼻黏膜静脉丛直接交通；因此，鼻黏膜水肿可引起静脉丛充血，继而压迫鼻泪管。

图1. 泪道系统的解剖。A，正常泪道的非影像学解剖示意图。插图是面部冠位CT、骨窗，显示泪道的正常影像学解剖，蓝箭表示泪腺（L）产生的泪的移动，然后经泪道引流至下鼻道（Inf. Meatus）；泪道由上泪点（SP）和下泪点（IP）、上泪小管（SC）和下泪小管（IC）、泪总管（CC）、Rosenmüller瓣、泪囊（Sac）、鼻泪管（NL duct）和Hasner褶（即Hasner瓣）组成。（Oerding S绘图，经许可使用。）B，62岁男性。轴位CT、骨窗显示泪囊窝由上颌骨额突的泪前嵴（直箭）和泪骨的泪后嵴（弯箭）形成。正常情况下泪囊由液体（泪）填充（左侧泪囊）或空气填充（右侧泪囊）。插图是轴位CT、软组织窗显示眼轮匝肌前支（直箭）和后支（弯箭）包裹泪囊，因此泪囊是眶隔前结构。Cross-SectionalImaging Modalities of the Nasolacrimal Drainage Apparatus泪道系统的断层成像方式Modalities for cross-sectional imaging of the nasolacrimal drainageapparatus include CT, MRI, ultrasound (US), and nuclear scintigraphy. Conventionaldacryocystography can depict the intrinsic pathologic findings of the lacrimaldrainage system. However, it is limited in its ability to offer informationextrinsic to the nasolacrimal drainage system and provides limited soft-tissue detail[10]. CT is often the initial modality of choice because it delineates thelacrimal system anatomy, shows most nasolacrimal drainage apparatus abnormalitiesand their extent, and facilitates preoperative planning [11]. It is the best modalityfor assessing bony details and looking for bony erosions [10]. It is also veryfast, allowing scanning of the uncooperative patient; however, it results inexposure to ionizing radiation. Unenhanced CT of the orbit or face is theappropriate modality for scanning traumatic cases, whereas contrast-enhanced CTof the orbit or face is generally reserved for inflammatory, infectious, neoplastic,and postoperative lesions [12].泪道系统的断层成像方式包括CT、MRI、超声（US）和核显像。传统的泪囊造影可以显示泪道内在病变，但提供泪道外部信息的能力有限，软组织细节不足。CT通常是首选的检查方法，因为它能够给出泪道系统管的解剖结构，显示大多数泪道疾病及其累及范围，有利于制定手术计划。它是评估骨细节和寻找骨侵蚀的最佳方式。CT扫描很快，稍有不合作的患者也可以完成检查；然而，患者有暴露于离子放射的风险。眶部或面部的未增强CT是检查外伤病例的适当方式，眶部和面部的增强CT则一般用于炎症、感染、肿瘤和术后病变。Unlike CT, MRI does not use ionizing radiation and has higher soft-tissuecontrast resolution, allowing better differentiation between the solid andcystic components of nasolacrimal drainage apparatus lesions and betterassessment of extension of the lesions to surrounding structures such as theorbital fat. Contrast-enhanced MRI is indicated for neoplastic lesions and maybe indicated for complicated inflammatory or infectious cases [13]. The disadvantagesof MRI include its higher cost; substantially longer scanning time, which ischallenging when imaging pediatric and uncooperative patients; its use ofclosed-bore systems more often than CT, thereby increasing the risk of patientsbecoming claustrophobic; and the fact that it is not safe for patients withsome metal implants and foreign bodies [13]. Contraindications to bothcontrast-enhanced CT and MRI include a history of allergy to contrast media andpoor renal function.与CT不同，MRI不使用离子放射，软组织分辨率高，能够更好地鉴别泪道系统管的实性与囊性病变，更好地评估病变累及周围结构的范围如眶脂肪。增强MRI适用于肿瘤性病变，也可用于复杂炎症或感染。MRI的缺点包括费用高、扫描时间较长（对儿童和不合作的患者可能较困难）、增加了患者幽闭恐惧的风险（因为空间相对封闭）、对某些金属植入体内或异物的患者不安全。增强CT和增强MRI的禁忌症包括对比剂过敏史、肾功能差。US can detect dacryocystocele during the prenatal period and can differentiatecystic       from solid structures. USdoes not use ionizing radiation, is cheap, and is readily available in mostinstitutions; however, its use requires experience, and it cannot evaluate bone[14].超声可在产前发现泪囊囊肿，能够鉴别囊性结构和实性结构。超声不使用离子放射，价格便宜，大多数机构都有超声检查仪器；但是，超声检查需要医生经验，并且不能评估骨。Although dacryoscintigraphy performed using a 99mTc-pertechnetatesolution is a physiologic study of the lacrimal drainage system, it is limitedby its suboptimal resolution and lack of easy availability [13]. Both conventionalMRI and CT do not show superior, inferior, and common canalicular pathologicfindings [14]; therefore, some investigators have advocated the use of CT orMRI dacryocystography, each of which has its own advantages and limitations[13, 15].使用99mTc高锝酸盐溶液进行泪囊造影是泪道的生理学研究，但分辨率并不很理想，并不容易获取。传统MRI和CT不能显示上下泪小管和泪总管病变，因而一些学者提倡使用CT或MRI造影，各有其优缺点。Developmental and CongenitalLesions发育性或先天性病变Punctal membranes open at full term. Punctal atresia can be seen onsimple inspection.泪点膜足月开放。通过简单望诊即可看到泪点闭锁。Although  the  Hasner valve  remains  imperforate in 70% of neonates, only 6% of neonateswill present with epiphora [9] because by 1 month of age the increasedintracanalicular pressure during early inspiratory effort and crying results inrupture of the Hasner valve. This is also a result of the low rate of tearproduction during early infancy [3].70%新生儿Hasner瓣仍关闭，但仅有6%新生儿有溢泪，因为1月龄时吸气和哭闹引起泪小管内压增加、导致Hasner瓣破裂。另外一个原因是婴儿早期泪液分泌率低。Congenital dacryocystocele is believed to result from concomitantupper obstruction of the Rosenmüller valve and lower obstruction of the Hasnervalve [16–18]. It presents as a grayish blue cystic swelling just below themedial canthus and is bilateral in approximately 25% [19] of infants, withsecondary dacryocystitis frequently developing within days or weeks [20, 21].Ultrasound is used to confirm the cystic nature of the lesion, thus reliablyexcluding other differential considerations like hemangioma, glioma, dermoid,encephalocele, and malignant processes [16, 22–25]. CT and MRI are indicated ifUS results are inconclusive. CT has the advantage of showing the bony details withthe penalty of radiation exposure (Fig. 2), whereas MRI is better atcharacterizing contents of the cyst without the radiation penalty [16]. Bothmodalities are excellent in detecting rim enhancement and surroundingsoft-tissue stranding indicating secondary dacryocystitis. Dacryocystocele mayextend intranasally, forming an inferior meatus nasal cyst that may obstructthe nasal cavity and lead to neonatal respiratory distress because neonates areobligate nasal breathers [16]. Endoscopic marsupialization is the treatment ofchoice [23].先天性泪囊囊肿的原因被认为是上游Rosenmüller瓣下游阻塞和Hasner瓣阻塞同时存在。表现为内眦下方灰蓝色囊性隆起。婴儿双侧患病者占25%。常在数天或数周内继发性泪囊炎。使用超声来确定病变的囊性本质，这样就能可靠地除外其他需要鉴别的病变如血管瘤、胶质瘤、皮样囊肿、脑膨出和恶性肿瘤。如果超声检查结果不确定，则需要CT和MRI。CT优点是显示骨细节，缺点是放射暴露（图2），MRI优点是显示囊性内容物更好，并且没有放射暴露问题。CT和MRI都能够很好地发现边缘强化和周围软组织索条影，提示继发性泪囊炎。泪囊囊肿可累及鼻内，形成下鼻道鼻囊肿，可阻塞鼻腔，导致新生儿呼吸窘迫，因为新生儿是专性鼻通气者。内窥镜下开窗造口术是首选治疗。

图2. 男童，5周龄，双侧先天性泪囊囊肿，右眼内眦有淡蓝色囊性硬的肿物。本图（轴位CT，插图是冠位CT）显示泪囊囊肿的经典三联征：轴位CT显示内眦囊性肿物（箭头），插图显示鼻泪管扩张（实箭）、与之延续的位于下鼻道的鼻腔粘膜下肿物（破折箭，闭合膜向下隆起至鼻腔）。这样的鼻腔占位有可能引起鼻腔阻塞，进而导致新生儿呼吸窘迫，影像科医生应熟悉这一情况，若发现应迅速与临床医生沟通。Traumatic Lesions外伤Nasolacrimal trauma can be divided into temporary and permanentdysfunction. Temporary dysfunction is the result of posttraumatic edema andtypically resolves spontaneously. Permanent dysfunction is caused by eitherdirect traumatic injury to the nasolacrimal drainage apparatus or iatrogenicinjury secondary to hardware application for open reduction and internalfixation [26]. Nasoorbitoethmoidal fracture is the leading cause of traumaticnasolacrimal obstruction [26–29], whereas iatrogenic injury can occur afterlacrimal, orbital, or sinus rhinoplasty or after other craniofacial surgery[30].泪道外伤可分为暂时性和永久性功能异常。暂时性功能异常的原因是外伤后水肿，一般自发缓解。永久性功能异常的原因是泪道受到直接外伤损伤，或继发于开放复位或内固定手术的医源性损伤。鼻眶筛骨折是外伤性泪道阻塞的首要原因，医源性损伤则可发生于泪道、眶或鼻窦整形术后或其他颅面手术后。In a study by Garg et al. [31], approximately 9.5% of patients witha craniofacial fracture had an associated nasolacrimal drainage apparatusfracture. The estimated rate of epiphora or dacryocystitis among these patientswas approximately 10%. Garg and colleagues described five nasolacrimal drainageapparatus fracture findings that are significantly associated with the developmentof lacrimal outflow obstruction (Fig. 3). However, because the patency of thecanal is often restored with open reduction and internal fixation and becauseCT is insensitive for canalicular soft tissue injuries or scarring,radiologists should be aware that neither preoperative nor postoperative CT hasmuch prognostic value for nasolacrimal drainage apparatus obstruction. Thisdiagnosis is made on the basis of an accurate history (findings of chronicepiphora, recurrent dacryocystoceles, or dacryocystitis) and physicalexamination revealing nasolacrimal drainage apparatus obstruction with the useof irrigation or tear flow studies or frank dacryocystitis. The utility of CTis primarily relegated to evaluation of delayed complications such as an infecteddacryocystocele [27, 31].在Garg et al.的一项研究中，颅面骨折患者约9.5%有泪道骨折。据估计这些患者溢泪或泪囊炎的发生率约10%。Garg及其团队描述了与泪液排出受阻显著相关的5种泪道骨折表现（图3）。因为开放复位和内固定术后有泪道恢复可能，并且CT对泪管软组织损伤或瘢痕并不敏感，所以影像科医生应当知晓术前和术后CT对泪道阻塞的预测意义并不大。诊断依据是准确的病史（慢性溢泪、复发性泪囊囊肿或泪囊炎）、泪道冲洗或泪液流出研究显示泪阻塞或单纯泪囊炎。CT主要用于评估晚期并发症如感染性泪囊囊肿。

图3. 泪道骨折患者的5个影像学特点，与外伤后泪道阻塞显著相关。A，男性，34岁，外伤后。轴位CT显示鼻颌支撑壁明显移位，鼻泪管压缩超过50%。B，男性，42岁，外伤后。轴位CT显示泪前嵴或泪后嵴撕裂伤。C，男性，28岁，外伤后。轴位CT显示泪囊窝或鼻泪道的骨碎片（箭）。Inflammatory Lesions炎性病变In a large meta-analysis of 420 primary lacrimal sac lesions,inflammatory lesions of the nasolacrimal drainage apparatus (e.g., pseudotumorsor granulomas) compromised up to 21% of all lacrimal sac masses [32–36].有一项meta分析纳入了420例原发性泪囊病变，其中炎性病变（例如炎性假瘤或肉芽肿）最多可占所有泪囊肿物的21%。Nasolacrimal drainage apparatus obstruction occurs in approximately10% of patients with ocular granulomatosis with polyangiitis, previously knownas Wegener granulomatosis [37, 38]. Evidence suggests that lacrimal drainagesystem disease is a direct consequence of focal granulomatosis withpolyangiitis vasculitis and is not a result of contiguous orbital pathologicfindings [37, 39, 40]. On cross-sectional imaging, granulomatosis withpolyangiitis presents with a characteristic erosive pattern including a largenasal septal defect and a large soft-tissue component eroding the lateral nasalcavities and the bony nasolacrimal drainage apparatus, which has low T2 signalintensity on MRI (Fig. 4). It is frequently complicated by chronicdacryocystitis [37, 39, 41, 42].眼部肉芽肿伴多血管炎（以前称为Wegener肉芽肿病）患者约10%有泪道阻塞。有证据表明发生泪道疾病的原因是局部肉芽肿伴多血管炎，不是眶部病变。断层影像上，肉芽肿伴多血管炎表现为特征性的侵蚀模式，包括鼻中隔大的缺损、大的软组织侵蚀鼻腔侧面和骨性鼻泪道，MRI表现为T2低信号（图4）。常并发慢性泪囊炎。

图4. 女性，46岁，主诉鼻部畸形、眼球突出、眶隔前肿胀。A，斜冠位、增强、最大密度投影CT，显示鼻中隔大的缺损，沿鼻腔外侧弥漫性软组织增厚，下鼻道阻塞，骨性鼻泪道内壁侵蚀，上述泪道浸润（箭头），泪囊阻塞并继发扩张（箭）。B，轴位T2加权MRI，软组织病变呈不均匀低信号（箭）。最终印象诊断是眶蜂窝织炎伴泪囊炎，因有骨侵蚀表现和T2低信号考虑可能是真菌病；但是病理结果显示肉芽肿伴多血管炎，以前称为Wegener肉芽肿病。大多数泪道疾病表现为T2高信号，因此如果发现T2低信号伴骨侵蚀，应考虑到肉芽肿伴多血管炎可能。Several other inflammatory and infiltrative diseases have beenreported to also involve the nasolacrimal drainage apparatus, including but notlimited to sarcoidosis (approximately 2–8% of cases [43], idiopathic orbitalinflammation (orbital pseudotumor), IgG4-related ophthalmic diseases [44], andSjögren syndrome [45].据报道其他一些炎性和浸润性病变也会累及泪道，包括但不限于结节病（占所有病例的2-8%）、特发性眶炎（眶炎性假瘤）、IgG4相关眼病和Sjögren综合征。Infectious Dacryocystitis感染性泪囊炎Dacryocystitis has a bimodal age distribution, predominantlyaffecting neonates and adults older than 40 years [46]. Patients usuallypresent with epiphora, a tender medial canthal mass, and frequentlymucopurulent discharge from the puncta. Secondary conjunctivitis, periorbitalcellulitis, and lacrimal sac abscess may also occur [3, 46]. Obstruction orstricture of the nasolacrimal drainage apparatus usually is the inciting factor[46]. The obstruction may be congenital or acquired and may be inflammatory,infectious, infiltrative, traumatic, or neoplastic. Conditions causing nasalmucosal edema may also lead to nasolacrimal drainage apparatus obstructionbecause of the direct communication of the nasolacrimal drainage apparatus andthe nasal venous plexuses [3]. Most cases do not require imaging and arediagnosed clinically and treated with systemic antibiotics. Imaging isindicated to exclude secondary orbital cellulitis or orbital abscess, which israre because the orbital septum acts as a barrier against postseptal spread ofthe infection. The presence of orbital cellulitis may require hospitalizationand parenteral antibiotics, whereas progression to an orbital abscess mayrequire surgical intervention [47]. Radiologists should also strive todistinguish acute from chronic dacryocystitis (Fig. 5). Acute dacryocystitis istreated systemically, whereas chronic dacryocystitis may requiredacryocystorhinostomy (DCR) [3]. Imaging is also indicated to rule out aretained foreign body, dacryoliths, and suspected tumors, which are relativecontraindications to internal endoscopic DCR [48].泪囊炎的年龄分布呈双峰状，主要发生于新生儿和超过40岁的成年人。患者通常表现为溢泪、触痛的内眦肿物，常有黏液脓性分泌物从泪点排出。也可发生继发性结膜炎、眶周蜂窝织炎、泪囊脓肿。鼻泪管阻塞或狭窄通常是基础因素。阻塞可为先天性或获得性，可以是炎症、感染、浸润性病变、外伤或肿瘤。引起鼻黏膜水肿的病变也可导致鼻泪管阻塞，因为泪道与鼻静脉丛直接交通。大多数病例不需要影像学检查，临床诊断，全身抗菌药物治疗。影像学检查用于排除继发性眶蜂窝织炎或眶脓肿，这些情况罕见，因为眶隔是屏障，能够阻碍感染扩散至眶隔后。眶蜂窝织炎可能需要住院、使用静脉抗菌药治疗，发展至眶脓肿则可能需要手术。影像科医生也要尽量区别急性泪囊炎与慢性泪囊炎（图5）。急性泪囊炎需要全身抗菌药物治疗，而慢性泪囊炎则需要鼻腔泪囊吻合术（DCR）。影像学也适用于排除异物、泪道结石和可疑肿瘤，这些是内镜DCR的相对禁忌症。

图5. 急性泪囊炎与慢性泪囊炎的鉴别。A，女性，40岁，左眼内眦和眶周肿胀。轴位增强CT显示泪囊囊性病变。图像特点符合急性泪囊炎表现，包括边缘厚且强化（箭）、相邻软组织广泛眶隔前蜂窝织炎（箭头）。B，男性，49岁，头晕（dizziness）。轴位T2加权MRI，泪囊囊性病变，周围软组织无肿胀或炎症（箭），符合慢性泪囊炎表现。Neoplastic Diseases of theNasolacrimal Drainage Apparatus泪道肿瘤If diagnosed early, rare nasolacrimal drainage apparatus tumors [36]are potentially curable [49, 50]. However, in many cases the diagnosis is delayedbecause the presentation simulates more common benign conditions such asdacryocystitis [50].泪道肿瘤罕见，如果早期诊断，有可能治愈。但是，一些病例诊断延误，因为表现类似良性病变如泪囊炎，后者更常见。In their meta-analysis of 420 primary lacrimal sac lesions, Heindlet al. [33] found that epithelial tumors accounted for 70% of cases, followedby mesenchymal tumors (12%), lymphoid lesions (11%), malignant melanoma (4%),and other lesions (1%), and they determined that 72% of the lesions weremalignant [33]. Papilloma is the most frequently reported benign tumor; otherbenign tumors include oncocytoma and fibroma [5, 33, 51] (Fig. 6). Squamouscell carcinoma (Fig. 7) and lymphoma are the most common malignant tumors [5,33, 51]. Other malignant tumors include transitional cell carcinoma,adenocarcinoma, adenoid cystic carcinoma, and malignant melanoma [5]. Secondarytumors can develop from tumors arising from adjacent structures (e.g., theeyelids, conjunctiva, orbit, paranasal sinuses, and nose) [1, 5, 36, 52–54](Fig. 8). Distant metastatic tumors of the nasolacrimal drainage apparatus areextremely rare [33, 36, 52–54].Heindl et al.进行了一项meta分析，纳入420例原发性泪囊肿瘤，其中上皮性肿瘤占70%，间质性肿瘤占12%，淋巴样肿瘤占11%，恶性黑色素瘤占4%，其他占1%；恶性肿瘤占72%。良性肿瘤在报道中最常见的是乳头状瘤，其他包括嗜酸细胞瘤和纤维瘤（图6）。鳞状细胞癌（图7）和淋巴瘤是最常见的恶性肿瘤。其他恶性肿瘤包括移行细胞癌、腺癌、腺样囊性癌和恶性黑色素瘤。继发性肿瘤是源自相邻组织（即眼睑、结膜、眶、副鼻窦和鼻）的肿瘤（图8）。泪道肿瘤的远处转移极其罕见。

图6. 男童，9月龄，内眦肿胀，皮肤异常呈紫色，新发打鼾，右侧副鼻窦肿物。A，轴位T2加权MRI，边界清楚的、扩张性的、囊样病变，以右侧泪囊区为中心。B，冠位增强T1加权MRI，病变不均匀增强，病灶内线状或弯带状低信号。开始时诊断为泪囊炎，内含液体（蛋白含量高）。病理诊断硬纤维瘤病。该病罕见，泪囊内线状或弯带状低信号提示高度胶原化组织，增加了硬纤维瘤病诊断可能。

图7. 女性，49岁，复发性右眼霰粒肿2年，右眼溢泪，内眦小结节，病理证实是鳞状细胞癌。A图是抑脂冠位T2WI，B图是轴位T2WI，C图是抑脂、轴位、增强T1WI，显示右侧泪囊强化的实性肿物，导致骨平缓扩张，病变向上至内眦，向下至下鼻道，符合肿瘤表现，不符合囊性泪囊囊肿表现。

图8. 女性，72岁，左侧内眦区肿物，面部感觉异常。A，轴位增强CT，侵犯左侧泪囊的多间隙强化浸润性病灶（箭）。B，轴位增强CT，病变浸润左侧上颌前的皮下区（箭头），沿神经蔓延至左眶下神经（箭）。C，轴位增强CT，肿瘤在翼腭窝内（箭头）沿左侧三叉神经的上颌支（Ⅴ2）蔓延，右侧翼腭窝（箭）正常。病理结果是左眶的结外边缘区淋巴瘤，蔓延至泪道。Because of their rarity, and unlike most head and neck cancers,nasolacrimal drainage apparatus tumors are not staged using the American JointCommittee on Cancer TNM system [55]; instead, current staging practices arebased on a few case series and a small number of isolated case reports.Management of lacrimal sac tumors depends on their histologic type, size, andextent as well as the general health of the patient [56].由于泪道肿瘤罕见，并且与大多数头颈部肿瘤不同，所以泪道肿瘤不使用美国癌症联合会的TNM分期；现有的分期以一些病例研究和病例报道为基础。泪囊肿瘤的治疗取决于组织学类型、大小、范围和患者的一般健康状况。Early lacrimal sac tumors may not be readily visible oncross-sectional imaging, and dacryocystograms may provide more informationabout the extent and nature of the lesion [57, 58]. Imaging, however, isessential in the diagnostic differentiation of nasolacrimal drainage apparatustumors from chronic inflammatory conditions, which can mimic nasolacrimaldrainage apparatus neoplasms [33, 54].早期的泪囊肿瘤在断层影像上可能不易看到，泪囊造影可以提供关于病变范围和性质的更多信息。但是在鉴别诊断泪道肿瘤与慢性炎症时，二者可能表现相似，需要进行影像学检查。In addition to showing the nasolacrimal drainage apparatus mass andits extensions, CT is the best modality for the detection of any adjacent bonyerosion [56]. With its higher soft-tissue resolution, contrast-enhanced MRIwould show superior tumor definition, differentiate between the tumor and itspostobstructive cyst formation, and provide better definition of tumorextension into the adjacent soft-tissue structures, including the orbital fat.CT dacryocystography of the lacrimal drainage system would show lacrimal sacfilling defect by the space-occupying lesion or delayed disappearance ofcontrast medium and would also show the extent of obstruction. Radiologicimaging is also valuable in detecting residual or recurrent masses onpostoperative follow-up [58–60].CT除了能够显示泪道肿物及其范围，还是检测任何相邻骨侵蚀的最佳方法。增强MRI软组织分辨率高，能够更好地清晰显示肿瘤、鉴别肿瘤与阻塞后囊肿，对肿瘤累及相邻软组织范围能够提供更好的信息（包括眶脂肪）。CT泪道造影能够显示泪囊充盈缺损（占位效应）或对比剂消失延迟，也会显示阻塞程度。放射影像在术后随访检查肿物残留或肿物复发时也很有价值。For benign epithelial or mesenchymal tumors confined to the lacrimalsac, DCR may suffice [56]. Traditional treatment of malignant lacrimal sactumors has been complete excision of the tumor and lacrimal drainage system,including the canaliculi and nasolacrimal duct, followed by radiotherapy,adjuvant chemotherapy, or both [60].对局限于泪囊的良性上皮性或间质肿瘤而言，治疗方法用DCR可能足够了。传统的治疗泪囊恶性肿瘤的方法是完全切除肿瘤和泪道系统，包括泪管和鼻泪管，继之以放疗、辅助化疗或二者联合。The goal of the surgeon is to achieve a safety margin with the leastamount of resection and morbidity possible. The radiologist plays a pivotalrole in achieving this goal by assessing the local, nodal, and distant extentof the tumor [56, 60]. Key radiologic findings are involvement of the medialcanthal soft tissue, bony nasolacrimal drainage apparatus [5], orbits, andsinuses as well as perineural spread to the inferior alveolar nerve (Fig. 7).Extension of premalignant and malignant lesions down the nasolacrimal duct isstrongly believed to account for recurrences and treatment failure [61].Radiologic evidence of tumor extension beyond the lacrimal drainage apparatus intothe orbits or sinuses would dictate a more radical surgery, such as orbitalexenteration, lateral rhinotomy, or paranasal sinus resection [60, 61].Postoperative radiotherapy or chemotherapy may be indicated if there is bonyinvasion, lymphatic invasion, or both types of invasion or if neoplastic cellsare present at the surgical margins [56]. Postoperative radiation may beindicated with perineural tumor spread [60, 62].术者目标是在最大量切除病变与疾病影响之间达到一个安全限度。在实现这一目标的过程中，影像科医生评估肿瘤的局部范围、是否累及淋巴结和远处转移，起着关键作用。重点是内眦区软组织、骨性鼻泪道、眶、鼻窦、沿神经向下蔓延至下牙槽神经（图7）。癌前病变和恶性病变沿鼻泪管向下蔓延被认为是肿瘤复发和治疗失败的原因。如果影像学证据提示肿瘤超出泪道范围，进入眶或鼻窦，那就可能需要更彻底的手术如眶内容剜除、侧鼻切开或鼻窦切除。如果有骨侵蚀、淋巴侵袭或二者兼有，或手术切缘有肿瘤细胞，可能需要术后放疗或化疗。若肿瘤沿神经蔓延，可能需要术后放疗。Radiologists also play a pivotal role in the assessment of nodal anddistant metastatic disease (Appendix 1). Ni et al. [59] found nodal metastasisin 28% of patients, generally months to years after the initial diagnosis. Theyalso found distant metastases in only six of 74 patients and intracranial tumorspread in one of 74 patients. Given the high rate of local recurrence oflacrimal sac tumors, patients must undergo lifelong follow-up after receivingappropriate treatment [51, 60].影像科医生压在评估淋巴结和远处转移方面具有关键作用（附录1）。Ni et al.报道28%患者有淋巴结转移，发生于初诊后数月或数年。在74例患者中，远处转移仅有6例，颅内蔓延仅有1例。因为泪囊肿瘤局部复发率高，患者在适当治疗后应终生随访。

附录1：对恶性泪道肿瘤的影像评估内容（源自Kumar et al[5]）累及内眦区软组织骨性鼻泪道受累眶隔前或眶隔后和肌锥内或肌锥外蔓延副鼻窦沿神经蔓延至眶下神经（Ⅴ2）淋巴结转移罕见远处转移Nasolacrimal Drainage ApparatusSurgery泪道手术Surgeries and Stents手术与支架The most common surgery for nasolacrimal drainage apparatus is DCRin which the medial wall of the lacrimal sac is opened into the nasal cavity.DCR is the procedure of choice for treating epiphora secondary to obstructionor severe stenosis of the distal lacrimal sac and the nasolacrimal duct. It canbe performed externally through the skin or endoscopically through the nose[3]. DCR is recognized radiographically by the characteristic well-definedosteotomy defect in the medial wall of the bony lacrimal sac (Fig. 9A). Thisshould not be mistaken for a fracture.泪道手术最常见的是DCR，将泪囊内侧壁开放至鼻腔内。DCR是治疗远端泪囊和鼻泪管阻塞或严重狭窄（导致溢泪）的首选。可经皮完成，也可经鼻内镜下操作。DCR的影像学特征是泪囊内侧清晰的骨缺损（图9A）。不要误诊为骨折。Stents支架Stenosis or occlusion within the upper drainage system proximal tothe lacrimal sac may require placement of fine polymeric silicone (Silastic,Dow Corning) stents within the canaliculi to complement DCR.靠近泪囊的上泪道系统的狭窄或阻塞可能需要植入细的聚合硅管支架（Silastic, Dow Corning）来辅助DCR。The two main types of stents are bicanalicular and monocanalicularstents. Bicanalicular stents pass through both the upper and lower canaliculus,extend through the lacrimal sac and lacrimal duct, and are secured in theinferior meatus (Fig. 9B). Monocanalicular stents are placed in either theupper or lower canaliculus, extending only into the lacrimal sac [63] (Figs. 9Cand 9D).泪道支架最主要的两种类型是双泪小管型和单泪小管型。双泪小管支架经上泪小管和下泪小管植入，经泪囊和鼻泪管，固定于下鼻道（图9B）。单泪小管支架经上泪小管或下泪小管植入，进入泪囊为止（图9和9D）。Use of a lacrimal bypass tube (Jones tube) is an uncommon stentingtechnique performed when the lacrimal system is completely scarred or notpresent. A Jones tube is a clear, low-thermal-expansion borosilicate glass tubeplaced from the conjunctival cul-de-sac through a surgically created bonyostium and exiting into the nose; it is radiodense on CT [64, 65] (Fig. 9E).Most other stents are made of silicon or polyurethane; however, radiologistsshould check individual manufacturer’s instructions to confirm MRIcompatibility. Radiologists should also be familiar with different types ofstents to avoid mistaking them for a foreign body or calcification and tooccasionally assess the positioning of the stents.泪道旁路管（Jones管）并不常用，它用于泪道系统完全瘢痕化或没有泪道的情况。它是透明、低热膨胀的硼硅酸盐玻璃管，从结膜囊进入，经骨孔（手术造孔）进入鼻腔；CT上呈高密度（图9E）。大多数支架材料是硅或聚氨酯。影像科医生应检查各制造商说明书，确认MRI的兼容性；也应熟悉不同类型支架，避免将其当做异物或钙化，并且有时需要评估支架的位置。

图9. 泪道相关手术和支架。A，女性，46岁，颅底软骨肉瘤切除术后并发面神经麻痹，继而出现左眼暴露性角膜病变和未愈的神经营养性角膜溃疡，怀疑左侧眶隔前蜂窝织炎。也进行了金质负荷物（因感染）取出手术和多处睑缘缝合术。冠位CT显示特征性的清晰的DCR骨性缺损（箭）。B，是A图同一位患者。斜冠位、最大密度投影、重建CT，双泪小管支架形成的环（箭）位置良好，经DCR伸入鼻腔。C，女性，69岁，车祸伤后，下睑修复，鼻泪管支架和单泪小管支架用于重建眦部切除后的下泪小管缺失。轴位CT显示内眦区环形支架（Mini Minoka, FCI Ophthalmics）（箭头）清晰。D，是C图同一位患者。斜冠位CT证实单泪小管硅支架（MiniMinoka）位置良好，从左侧内眦区（椭圆形）延伸至鼻泪管。请注意硅管的斜端。E，女性，79岁，外伤后持续性头痛。轴位CT显示右侧不透射线的Jones管（椭圆形），由透明、低热膨胀的硼硅玻璃制成，可能会被误认为是右侧鼻泪管内的高密度病灶（异物）。PosttreatmentComplications术后并发症Imaging can play a role in the assessment of postoperative complicationsof nasolacrimal drainage apparatus surgery, including failure and recurrence ofepiphora or purulent discharge, scar formation, wound infection, and granulomaformation [66]. Radiologists should also be aware of certain chemotherapeuticagents that might result in nasolacrimal drainage apparatus obstruction.Docetaxel and 5-fluorouracil are the chemotherapeutic drugs best documented tocause epiphora mainly by causing canalicular stenosis. Drugs less commonlyreported to cause epiphora include S-1 (the combination of tegafur, gimeracil,and oteracil), capecitabine, imatinib, and topical mitomycin C [67].Radioactive iodine treatment of thyroid cancer and radiation therapy to thenasolacrimal drainage apparatus area may also result in acquired nasolacrimaldrainage apparatus stenosis or obstruction [67].影像学在评估泪道术后并发症也有价值，包括治疗失败、溢泪复发或脓性分泌物、瘢痕形成、伤口感染、肉芽肿形成。影像科医生也要知道某些化疗药物可能会引起泪道阻塞。文献记录最多的导致泪小管狭窄、引起溢泪的化疗药物是多西紫杉醇和5-氟尿嘧啶。较少报道的引起溢泪的药物包括S-1（替加氟、吉美拉西和奥特拉西联合用药）、卡培他滨、伊马替尼和局部丝裂霉素。甲状腺癌的放射碘治疗和对泪道区的放疗也可能引起获得性泪道狭窄或阻塞。Pitfalls陷阱Pseudodacryocystitis is anterior ethmoiditis or ethmoid mucoceleextending into the adjacent nasolacrimal drainage apparatus and clinicallysimulating dacryocystitis. Pseudodacryocystitis can be clinicallydifferentiated from dacryocystitis by observation of a patent nasolacrimaldrainage apparatus on irrigation, whereas imaging reveals dacryocystitis aswell as anterior ethmoid sinusitis with bony erosion between the sinus and thenasolacrimal drainage apparatus. After failed medical management, treatment ofpseudodacryocystits is anterior ethmoidectomy [68] (Fig. 10).假性泪囊炎是前部筛窦炎或筛窦黏液囊肿累及相邻泪道，临床上与泪囊炎表现相似。假性泪囊炎与泪囊炎的临床鉴别是前者冲洗泪道通畅，影像学检查显示泪囊炎和前部筛窦炎，并且在鼻窦和泪道之间有骨侵蚀。若药物治疗无效，假性泪囊炎的治疗方式是前部筛窦切除（图10）。

图10. 男童，10岁，假性泪囊炎，完全接种免疫，表现为右眼肿，尤其是内眦区。轴位CT，右侧急性泪囊炎（实箭），眶周的眶隔前蜂窝织炎（箭头），眶隔后、骨膜下眶脓肿（破折箭）及其与之相关的急性筛窦炎（星号）。插图是轴位CT、窗位稍高于骨窗，骨性鼻泪管内侧不连续，这一表现与急性筛窦炎一致（椭圆）。假性泪囊炎源自前筛窦，临床表现可与急性泪囊炎相似，影像科医生的作用是提醒临床医生，因为假性泪囊炎的治疗与急性泪囊炎不同。Conclusion结论Accurate radiologic diagnosis of nasolacrimal drainage apparatusdisease requires a clear understanding of normal nasolacrimal drainageapparatus anatomy as well as the presentation of common inflammatory,neoplastic, and postsurgical changes resulting in clinical disease. Mastery ofthis knowledge provides the basis for better communication between radiologistsand clinicians, which will result in better patient care.准确影像学诊断泪道疾病需要清楚了解正常泪道解剖和与常见炎症、肿瘤和术后改变。掌握这些知识为影像科医师与临床医生之间更好地沟通奠定基础，这对患者有益。（正文结束）