Paranasopharyngeal space involvement in nasopharyngeal cancer: detection by CT and MRI

Paranasopharyngeal tumour extension (PTE) from nasopharyngeal carcinoma (NPC) is staged in its own subgroup in the American Joint Committee on Cancer classification. Most large clinical trials use computed tomography (CT) to stage PTE, but diagnosis relies on indirect signs of tumour invasion such as asymmetry of the parapharyngeal fat. Magnetic resonance imaging (MRI) has the advantage of directly revealing PTE because of its ability to depict the complex anatomical structures that form the boundary of the nasopharynx. The aim of this study was to compare CT and MRI in the identification of PTE and to determine whether the imaging modality used influenced staging of the disease. The MRI and CT scans of 78 patients (156 parapharyngeal regions) with NPC were assessed for PTE. On MRI, PTE was considered to be positive when there was tumour invasion through the complex anatomical structures of the nasopharyngeal wall. When using CT, it was considered positive when there was: (1) distortion of the parapharyngeal fat plane; or (2) extension beyond a line drawn from the medial pterygoid plate to the lateral aspect of the carotid artery. CT scanning and MRI were compared. PTE was judged to be present in 28 of 78 (36%) patients by MRI and in 41 of 78 (53%) scanning by CT when using criterion 1 or 2. An analysis of the discordant findings revealed that MRI was positive in three sides of the nasopharynx in early tumour extension through the pharyngobasilar fascia but not identified with CT by using criterion 1 or 2. MRI was negative in 20 and 21 sides of the nasopharynx that were judged to be positive on CT by using criterion 1 and 2 respectively. In these patients MRI revealed that the positive CT scan was caused by a large tumour compressing but not invading the parapharyngeal fat space, a metastatic lateral retropharyngeal node, or a combination of the two. The imaging modality used for staging NPC has an impact on the staging of PTE. CT scanning suggested the presence of PTE more frequently than MRI because of its inability to distinguish the primary tumour from lateral retropharyngeal nodes, and direct tumour invasion of the parapharyngeal region from tumour compression. The imaging modality and criteria used for staging PTE should be taken into consideration when assessing the results of clinical studies.     

鼻咽癌的CT与MRI对比分析

[目的]探讨CT和MRI对鼻咽癌的诊断价值。[方法]收集2003年10月到2005年1月,经病理证实的107例鼻咽癌患者,均行MRI和CT扫描,并根据临床资料和CT或MRI进行’92分期。[结果]MRI对于腔内病变的诊断以及翼腭窝、颞下窝、颈长肌、海绵窦、颅底、颈椎、咽后淋巴结、颈淋巴结等侵犯的检出要高于CT,而对鼻腔、口咽、咽旁间隙等检出与CT差别不大。根据’92分期原则,MRI相对于CT使33.6%(36/107)的病例发生了T分期改变。[结论]MRI对鼻咽癌的诊断、分期相对CT有优势。联合应用更有益。     

MRI在鼻咽癌分期中的作用

背景与目的:随着磁共振成像(magnetic resonance imaging,MRI)的广泛应用,MRI对于鼻咽癌的诊断价值已被证实明显优于CT.本研究旨在分析MRI与CT检查对鼻咽癌'92分期及6th UICC/AJCC分期的影响.方法:收集2003年1月至2004年6月收治的、经病理证实的初诊鼻咽癌250例,所有病例同时具有治疗前鼻咽和颈部的增强CT及MRI资料.结合临床资料如颅神经受损及颈淋巴结大小,分别采用CT和MRI检查进行'92分期及6th UICC/AJCC分期,评价两者之间的差异.结果:MRI在诊断鼻咽癌软组织超腔侵犯(口咽、鼻腔、咽旁间隙)、咽后淋巴结转移以及颅底骨质、副鼻窦、海绵窦/颅内、颞下窝及颈椎侵犯等方面均明显优于CT,而对于颈部巴结转移的检出两者无显著性差异.对于'92分期,MRI使32.0%的T分期发生改变(26.0%升级,6.0%降级);11.6%的N分期发生改变(6.4%升级,5.2%降级);30.4%的临床分期发生改变(24.0%升级,6.4%降级).对于6th UICC/AJCC分期,MRI使39.6%的T分期发生改变(36.0%升级,3.6%降级);9.2%的N分期发生改变(5.6%升级,3.6%降级);37.6%的临床分期发生改变(33.6%升级,4.0%降级).结论:MRI检测鼻咽癌局部病灶的侵犯范围要明显优于CT,而在颈部淋巴结转移的检出方面与CT结果相似.建立新的、以MRI为主要手段的鼻咽癌临床分期系统的研究具有临床必要性及可行性.     

鼻咽癌的CT与MRI对比研究

目的:比较CT与MRI对鼻咽癌侵犯部位检出率的差别;评价MRI相对于CT对92分期产生的影响.方法:收集2003年1月至2004年6月收治、经病理证实的初诊鼻咽癌250例,所有病例同时具有治疗前鼻咽和颈部的CT及MRI资料.在CT和MRI上分别评价各个解剖部位的受侵犯情况.结合临床资料分别采用CT和MRI进行92分期.结果:MRI对于鼻咽超腔、茎突前间隙、口咽、咽后淋巴结、颅底骨质、海绵窦、鼻窦、颈椎和颞下窝等侵犯的检出率明显高于CT,有统计学意义.CT与MRI对于鼻腔、茎突后间隙侵犯及颈部淋巴结的检出差别无统计学意义.MRI使32.0%的T分期发生改变;11.6%的N分期发生改变;30.0%的临床分期发生改变.结论:MRI对于诊断鼻咽癌的超腔侵犯、颅底骨质、鼻窦、海绵窦受侵,以及咽后淋巴结转移要明显优于CT;而在颈部淋巴结转移的检出方面与CT结果一致.MRI主要影响鼻咽癌92分期的T分期;对N分期影响不大,临床分期的改变将有利于指引治疗方案的调整.     

MRI、CT和PET-CT检查对鼻咽癌咽后淋巴结转移的诊断价值

背景与目的:三维适形调强放射治疗已成为鼻咽癌放射治疗发展的方向,靶区勾画的精确性显得尤为重要.本研究的目的是探讨MRI、CT以及18F-FDG PET-CT对鼻咽癌咽后淋巴结转移诊断的临床价值,为设计放射治疗计划提供参考.方法:收集2003年1月至2005年4月间中山大学肿瘤防治中心放疗科收治、经病理证实的初诊鼻咽癌87例,所有病例同时具有治疗前鼻咽和颈部的MRI、增强CT及PET.CT检查资料.在MRI、CT及PET-CT上分别评价鼻咽癌咽后淋巴结转移的检出率,比较采用χ2检验.结果:174侧(87例患者)咽旁间隙中,MRI、CT和PET-CT对鼻咽癌咽后淋巴结转移的检出率分别为44.8%、33.9%和24.1%.MRI对鼻咽癌咽后淋巴结转移的检出优于CT(P=0.037).MRI及CT对鼻咽癌咽后淋巴结转移的检出率高于.PET-CT,其差异均有统计学意义(P＜0.001,P=0.002).咽后淋巴结的最小径与PET-CT的标准摄取值呈正相关(r=0.832,P＜0.001).结论:MRI对咽后淋巴结转移的检出率高于CT及PET-CT.在鼻咽癌的三维适形调强放射治疗中,三者的结合应用将有利于提高靶区勾画的精确度.     

MRI对78例鼻咽癌患者临床分期的影响

背景与目的：目前国内鼻咽癌按92’福州分期进行临床分期,其主要依据是临床检查和CT检查。随着MRI在临床上普及应用,其对显示鼻咽癌侵犯范围更加敏感、精细,势将影响鼻咽癌的临床分期。本文通过对78例鼻咽癌患者的CT与MRI图像的比较,探讨MRI相对于以CT为基础,对鼻咽癌92’福州分期造成的影响。方法：回顾分析我院2005年8月至2006年8月收治的78例鼻咽癌患者放射治疗前的CT和MRI图像,所有病例均经病理证实。采用χ2检验分别以CT和MRI图像为依据的鼻咽癌92’福州分期的差异。结果：MRI和CT对鼻咽癌病变检出率分别为：茎突前间隙82.0%,65.4%;口咽34.6%,20.5%;咽后淋巴结74.4%,55.1%;颅底骨质51.3%,30.8%;海绵窦/颅内19.2%,5.1%;副鼻窦33.3%,19.2%;翼腭窝16.7%,6.4%等,差异均有显著性（P〈0.05）。鼻腔28.2%,21.8%;茎突后间隙侵犯65.4%,67.9%;喉咽2.6%,1.3%;以及对颈部淋巴结各区检出率等,差异无显著性。对T、N分期的影响：按照92’福州分期标准,MRI使42.3%的T分期发生改变;25.6%（20/78）的N分期发生改变。对临床分期的影响：按照92’福州分期标准,MRI使28.2%的临床分期发生改变。结论：以MRI作为鼻咽癌的检测手段,诊断更准确,尤其对颅底颅内病变和咽后淋巴结;临床分期改变幅度大,将影响对临床预后的评估;应考虑将MRI图像作为鼻咽癌的临床分期标准。     

MRI成像对鼻咽癌的分期、诊断及治疗优势的探讨

 目的
探讨鼻咽癌1992年福州分期和2008年分期差异、CT和MRI对鼻咽癌病变的检出率和原发肿瘤靶区(GTV）勾画和体积
计算的影响。方法收集89例初治鼻咽癌患者的CT和MRI图像,分别按1992年福州分期和2008年分期标准进行,比较
两种检查手段对各解剖部位的检出差异,挑选出CT与MRI检出有差异的39例,在TPS下进行GTV勾画及体积计算。结
果MRI在1992年福州分期中的参与使早期(T1+T2）构成比降低,晚期(T3+T4）构成比升高。鼻咽癌2008年分期使T3
、T4期患者增多。两种分期标准对T2、T3分期差异有统计学意义(P=0.033,0.008);在N1、N2的判断中,差异有统
计学意义(P<0.05)。MRI较CT对头长肌、咽旁间隙、海绵窦、副鼻窦及颅神经的检出率明显提高;在对咽后淋巴结
及颈部肿大淋巴结的形态、包膜、坏死、融合的显示方面明显优于CT。对39例CT和MRI成像有差异的病例进行靶区
勾画,结果显示GTVMRI>GTVCT。结论 根据MRI图像进行1992年福州分期发现了更多的晚期病例,需要进行综合治疗
(放疗+化疗）的患者增多,为治疗方案的选择提供了重要参考。以MRI为基础的2008年分期是指导鼻咽癌治疗的主
要标准。按照MRI图像进行肿瘤靶区勾画能有效避免CT图像对肿瘤组织的漏诊以及对正常组织的误诊,既能加强局
部控制,又能保护正常组织,对于鼻咽癌患者的治疗有利无弊。     

CT MRI和PET-CT对鼻咽癌局部肿瘤检测差异的初步研究

目的：比较CT、MRI和18F-PET-CT对鼻咽癌局部肿瘤的检测差异和探讨18F-PET-CT检测鼻咽癌局部肿瘤的应用价值。方法：2003年12月至2005年8月,中山大学肿瘤防治中心连续收治的原发鼻咽癌患者53例进入研究。所有患者在治疗前10天内以同一固定体位,完成增强CT、MRI和PET-CT扫描检查,在CT、MRI和PET-CT上分别读片判定鼻咽癌局部侵犯范围。结果：CT、MRI与PET-CT分别检出咽后淋巴结转移31例（58.5%）、36例（67.9%）、20例（37.7%）,CT、MRI检出率显著高于PET-CT（P=0.02,P=0.001）;CT稍低于MRI,但两者间无显著性差异（P=0.314）。CT和MRI检出的最大横径〈1cm的咽后淋巴结转移,PET-CT大部分未能显示;最大横径≤0.5cm或并发液化坏死明显的咽后淋巴结转移,PET-CT均未能检出。对鼻腔、口咽、咽旁间隙、颈动脉鞘区、颞下窝、翼腭窝和颅底骨质侵犯的检出,CT、MRI和PET-CT无明显差异;对海绵窦和鼻窦侵犯的检出,MRI可能优于CT和PET-CT。结论：对鼻咽癌局部肿瘤侵犯的检测,PET-CT较CT和MRI无明显优势;对最大横径〈1cm的咽后淋巴结转移,PET-CT的检出率明显低于CT或MRI;对最大横径≤0.5cm或并发液化坏死的咽后淋巴结转移的检测,PET-CT可能存在较大局限。     

基于MRI及IMRT下的鼻咽癌新T分期研究

目的 建立一个基于MRI并与IMRT相适应的鼻咽癌新T分期系统。方法 回顾分析2008—2010年我院基于MRI并接受IMRT的608例初治无转移鼻咽癌患者资料,按鼻咽癌第7版UICC/AJCC分期系统进行分期。Kaplan-Meier法计算相关生存率及Logrank检验,Cox法多因素分析。现行UICC/AJCC分期系统存在不足,在此基础上建立新鼻咽癌T分期系统,并对新T分期系统合理性进行评价。结果 5年随访率为94.5%,5年OS、DFS、LRFS、DMFS分别为81.5%、80.1%、86.0%、81.1%。单因素及多因素分析结果显示鼻咽、咽旁间隙、颅底解剖结构均为影响患者OS率因素(P=0.000—0.045)。根据风险差异性及生存曲线分布提出新T分期标准:T₁期:侵袭鼻咽、咽旁间隙、口咽、鼻腔、颅底、翼内肌;T₂期:侵袭翼外肌、鼻窦、眼眶、颅内、颞下窝、颅神经。推荐新T分期系统LRFS曲线及OS曲线均能很好地拉开。结论 推荐新T分期系统能较客观地预测鼻咽癌患者预后,可作为鼻咽癌临床新分期探索性的尝试。     

Influence of the Application of MRI on the T, N Staging System of Nasopharyngeal Carcinoma

OBJECTIVE To investigate the influence of utilizing MRI on the T, N staging system (the 5th edition, UICC) and on the 1992 China staging systems (Fuzhou-Guangzhou,China) by comparing the results of CT and MRI examinations of nasopharyngeal carcinoma (NPC).METHODS All 56 NPC patients, which were confirmed by histology,accepted both CT and MRI examinations. CT system scans were obtained by using an Elscient CT Twin Flash with the conventional axial scan. Three cases were examined by an additional coronary scan and 16 patients received an enhanced CT. The MR imaging was performed with a 0.5T MR system (Philips T5- II Ultra-Magnetic). The conventional axial, sagittal and coronary sections with SE sequences were obtained. The scan field was from the supra sellar cistern to the inferior border of C2. Most patients (50/56) accepted contrast enhanced MRI.RESULTS The pharyngobasilar fascia can clearly be seen on MRI but not on CT, so MRI can accurately determine the lesion in the nasopharyngeal cavity. MRI is more sensitive for evaluation of tumor involvement of soft tissue such as the Iongus colli muscle (14 cases by CT and 26 by MRI), tensor veli patalini muscle and levator veli palatini muscle (17 cases by CT and 23 by MRI), and skull-base bone marrow invasion (15 cases by CT and 42 by MRI). MRI can also demonstrate the invasion of the carotid sheath area and the enlargement of retropharyngeal lymph nodes more definitely than CT.The involvement of the trigeminal nerve can be detected on MRI, which may influence the clinical staging directly.CONCLUSION Of the 56 cases examined, 16 (28.6%) changed the staging based on UICC staging; while 33.9% (19/56) cases changed based on the 1992 China-stagin9 system. The major influence of MRI examinations on the 1992 staging was to differentiate the involvement of the carotid sheath area from metastasis of the retropharyngeal lymph nodes. There also was a significant difference in finding early invasion of the skull base.     

Prognostic factors of nasopharynx tumors investigated by MR imaging and the value of MR imaging in the newly published TNM staging

PURPOSE: To examine the usefulness of MR imaging for predicting local control of nasopharyngeal carcinoma (NPC) and the value of MR imaging in the newly published fifth edition of the TNM classification. METHODS AND MATERIALS: We studied 29 patients with NPC with MR imaging and CT before and after treatment. Staging was done according to the fourth and newly published fifth editions of the International Union Against Cancer (UICC) staging system. The radiotherapy protocol was designed to deliver 66 to 68 Gy to the primary tumor and clinically involved nodes. RESULTS: MR proved better than CT at identifying obliteration of the pharyngobasilar fascia, invasion of the sinus of Morgagni, through which the cartilaginous portion of the eustachian tube and the levator veli palatini muscle pass, invasion of the skull base, and metastases to lymph nodes in the carotid and retropharyngeal spaces. All seven patients without invasion of the pharyngobasilar fascia had local control. The local control rates of patients with invasion of the skull base were not good (60 to 73%). There was no apparent relationship between tumor volume determined by T1-weighted MR images and local control when the tumor volume was more than 20 cc. The newly published N staging system appears to successfully identify the high-risk group for distant metastasis as N3. In our series, four of five patients with N3 disease developed distant metastases. CONCLUSION: Deep infiltration of the tumor is a more important prognostic factor in NPC than tumor volume. Since the newly published T staging system requires a search for tumor invasion into soft tissue such as parapharyngeal space and bony structures, MR imaging may be indispensable for the newly published NPC staging system.     

鼻咽癌咽后淋巴结转移的CT与MRI对比研究

背景与目的：鼻咽癌是我国南方地区高发的恶性肿瘤,国外有些学者曾有过对鼻咽癌进行CT与MRI比较,但未有对鼻咽癌咽后淋巴结转移进行单独论述;国内目前也没有相关的论述。本研究通过对56例鼻咽癌的CT、MRI扫描所见进行比较分析,探讨CT与MRI对发现鼻咽癌咽后淋巴结转移的价值。方法：选取自1993年8月至2000年12月病理证实为鼻咽癌病例56例,CT扫描机是Elscient CT Twin flash,常规横断平扫,3例加冠状扫描,其中的16例直接增强扫描;MRI成像使用PhiliP T5-Ⅱ型0．5 Tesla超导磁共振成像系统,标准头部正交线圈,常规SE序列,扫描方向为横断面、矢状面、冠状面,扫描范围上鞍上池,下至第二颈椎下缘水平,大部分病例增强扫描（50／56）。结果：MRI可以准确区分鼻咽癌颈动脉鞘区肿瘤侵犯还是咽后淋巴结转移,较CT明确（CT13例,MRI24例）。统计学上有显著性差异（P＜0．05）。结论：MRI可以区分肿瘤直接侵犯颈动脉鞘区还是咽后淋巴结转移,因而较CT更准确划分肿瘤的侵犯范围,对我国的92分期影响较明显,可以更准确地进行鼻咽癌的临床分期。     

TUMORS INVADING PARAPHARYNGEAL SPACE : REFINED IMAGING DIAGNOSIS

ＴＵＭＯＲＳＩＮＶＡＤＩＮＧＰＡＲＡＰＨＡＲＹＮＧＥＡＬＳＰＡＣＥ：ＲＥＦＩＮＥＤＩＭＡＧＩＮＧＤＩＡＧＮＯＳＩＳＺｈｕａｎｇＱｉｘｉｎ庄奇新ＣｈｅｎｇＹｉｎｇｓｈｅｎｇ程英升ＹａｎｇＳｈｉｘｕｎ杨世埙Ｓｈａｎｇｋｅｚｈｏｎｇ尚克中ＹａｎＸｉｎｈｕａ...     

CT与MRI诊断鼻咽癌局部侵犯的价值探讨

目的 比较CT与MRI诊断鼻咽癌局部侵犯的价值.方法 回顾性分析60例鼻咽癌患者的临床资料,治疗前均行CT与MRI检查,比较两者对鼻咽癌患者局部侵犯的检出率及T分期的判断结果.结果 在对鼻咽部位的侵犯情况判断中,MRI检查对侵犯口咽、咽旁间隙、海绵窦的检出率均高于CT检查,差异均有统计学意义(P﹤0.05);而CT与MRI检查对侵犯翼腭窝、颞下窝、头长肌、副鼻窦的检出率比较,差异均无统计学意义(P﹥0.05).CT与MRI检查对侵犯颅底部位(蝶骨大翼、破裂孔、卵圆孔、斜坡)的检出率及T分期的判断结果比较,差异均无统计学意义(P﹥0.05).结论 在对鼻咽癌患者局部侵犯及T分期的判断中,CT与MRI检查均有效,但MRI检查对鼻咽部位局部侵犯的总检出率更高.     

应用磁共振成像技术探讨鼻咽癌咽后淋巴结转移的规律

目的采用磁共振成像(MRI)技术,探讨鼻咽癌咽后淋巴结转移的发生率、分布和转移规律。方法回顾性分析294例经病理证实的初治鼻咽癌患者的磁共振(MR)资料,分析咽后淋巴结转移与鼻咽癌原发灶侵犯部位、颈部淋巴结转移和鼻咽癌分期的关系。结果有165例(56.1%)患者发现有咽后淋巴结转移。从C1到C3水平,外侧组咽后淋巴结转移率呈递减趋势。口咽、鼻腔、茎突前后间隙侵犯和颈部淋巴结转移患者的咽后淋巴结转移率较高。294例患者中,有219例(74.5%)出现咽后淋巴结和颈部淋巴结转移,其中31例(10.5%)仅出现咽后淋巴结转移,54例(18.4%)仅出现颈部淋巴结转移,134例(45.6%)同时出现咽后和颈部淋巴结转移。T1、N0及Ⅰ期的患者咽后淋巴结转移率较低。结论咽后淋巴结转移与鼻咽癌早期局部侵犯及上颈链、颈后三角的淋巴结转移密切相关。咽后淋巴结和Ⅱ区颈部淋巴结均为是鼻咽癌淋巴结转移的首站。     

Magnetic resonance imaging and computed tomography features of nasopharyngeal carcinoma with maxillary sinus involvement

Anterior spread of nasopharyngeal carcinoma (NPC) may infiltrate the maxillary sinus. In a prospective study of 114 patients comparing magnetic resonance imaging (MRI) and computed tomography (CT) in the staging of NPC, 10 (9%) patients were noted to have tumour infiltration of the maxillary sinuses. All of the patients except one had associated infiltration of the sphenoidal sinuses indicating advanced local spread. Computed tomography was excellent in outlining the extent of bony erosion and associated soft tissue mass within the antra. T1-weighted images could not demonstrate bony erosions directly although soft tissue extension into the sinuses could be clearly visualized. Both CT and MRI showed good demarcation between tumour and mucosal thickening within the maxillary sinus. Although MRI demonstrated soft tissue involvement more elegantly than CT, it did not appear to offer significantly more information that may affect clinical management.     

MRI在鼻咽癌临床分期中的价值

背景与目的:鼻咽癌的临床分期主要依据影像学资料.本研究探讨磁共振成像(magnetic resonance imaging,MRI)技术在鼻咽癌'92临床分期中的价值.方法:2002年5月至2005年6月,共有100例经病理组织学诊断并在治疗前能同时或短时间内(不超过15天)作计算机断层扫描(computed tomography,CT)增强扫描和MRI增强扫描的鼻咽癌初治患者.其中男性74例,女性26例,年龄21～60岁,中位年龄46岁.分别计算两种检查方法所显示的各解剖部位受侵犯的阳性率,用卡方检验比较这两种检查方法对各解剖部位的检出率.按鼻咽癌'92分期标准,分别以CT加临床体检和MRI加临床体检对100例患者进行临床分期,用卡方检验比较两种方法所划分的各期病例数的构成比.结果:CT和MRI对颅底骨质破坏的检出率分别为31.0%(31/100)和56.0%(56/100),两种检查方法比较差异有显著性(χ2=12.715,P=0.000).CT和MRI对咽后淋巴结的检出率分别为40.0%和55.0%,差异有显著性(X2=4.511,P=0.034).对于T分期,用CT和MRI划分的各期病例数构成比差异有显著性(χ2=8.339,P=0.039),而CT和MRI对于N分期(χ2=0.275,P=0.965)和临床分期(χ2=5.525,P=0.137)划分的各期病例数构成比比较则无显著性差异.结论:MRI对鼻咽癌颅底骨质破坏和咽后淋巴结的检出率高于CT.MRI使鼻咽癌的T分期升级,对临床分期有升级的趋势,而对N分期则无影响.     

Value of computed tomography in staging the primary lesion (T-staging) of nasopharyngeal carcinoma (NPC): an analysis of 54 patients with special reference to the parapharyngeal space

CT scans of the nasopharynx and the base of skull were performed in 54 patients with histologically proven NPC. The CT findings are compared to those obtained by routine clinical examination. In this series, involvement of the parapharyngeal spaces was found by CT scan in 61% (33/54) of patients, which is impossible to assess by clinical means. Intracranial invasion was demonstrated by CT scan with intravenous contrast enhancement in five patients. CT is more sensitive in showing the erosion of skull base than X ray film. CT scans demonstrated 17% (5/30) of bony invasion in X ray negative patients. Clinical examination showed one involved wall in nine patients; CT scan discovered involvement of two or more walls in five (55%) of these nine. Routine clinical examination discovered extra-nasopharyngeal extensions in 34 locations, whereas CT scans discovered 106, a ratio of 1:3.1. The common sites of extra-nasopharyngeal extension detected by CT scan are: parapharyngeal space, intracranial invasion, sphenoidal sinus, orbit, ethmoidal sinus, maxillary antrum, oropharynx and the nasal cavity. In T-staging of NPC, 55% (6/11) of clinical T2 lesions are up-staged by CT. Thirty-six percent (4/11) of clinical T3 lesions were also up-staged. However, 94% (17/18) of clinical T4 lesions remained unchanged. Only 6% (1/18) of clinical T4 lesions were down-staged.     

Target Volume Definition in Rectal Cancer: What Is the Best Imaging Modality?

All patients with rectal cancer should undergo an accurate preoperative staging, including local staging for tumour extension and reliable staging for synchronous distant metastases. Imaging is of utmost importance as a basis for selecting the optimal treatment strategies and as an aid for precise target delineation. Anatomical imaging such as computed tomography (CT) and magnetic resonance imaging (MRI) have been the most commonly used pretreatment staging modalities, whereas endorectal ultrasonography may be useful for staging of smaller tumours (T2 or lower). MRI is the most accurate imaging technique for staging of T3 and T4 tumours. The role of fluorodeoxyglucose positron emission tomography (PET)/CT is under investigation, and diffusion-weighted MRI seems promising for prediction of pathological complete response. For target delineation, planning CT, preferably contrast-enhanced, is the most used imaging technique. For locally advanced tumours, coregistration with MRI or PET/CT may prove to be useful. In this article, the literature published on target delineation in rectal cancer radiotherapy is evaluated, with focus on the best imaging modality for volume definition and radiotherapy planning.     

鼻咽癌的影像学诊断——MRI、CT、PET—CT

随着现代医学科学的发展,医学影像学在鼻咽癌诊断中发挥了十分重要的作用。MRI具有良好的软组织对比度和多参数成像．可清晰地从形态学和功能改变方面为肿瘤的定位定性提供丰富的诊断信息;应用对比剂增强和压脂序列扫描是目前评估鼻咽癌病灶范围、分级分期的最佳影像学手段。CT扫描在诊断颅底骨质侵犯方面具备优势。PET—CT则在发现原发灶和远处转移方面具有较高的敏感性。全文就目前各种不同影像学检查对鼻咽癌的诊断进行评价．并着重介绍了MRI的应用。