中耳胆脂瘤扩散加权成像诊断研究进展

扩散加权成像（DWI）通过水分子的扩散在MRI图像中产生对比度,中耳胆脂瘤是一种角化性鳞状上皮异常生长的疾病,其在DWI上显示为特异性的高信号。已有多项研究支持将DWI作为中耳胆脂瘤的辅助检查手段应用于临床,认为其无论对于初发性中耳胆脂瘤还是复发性中耳胆脂瘤都具有很高的准确性,甚至可以一定程度上取代中耳胆脂瘤术后的二次探查手术。笔者就近年来中耳胆脂瘤诊断的扩散序列进展,以及扩散技术的定量分析与序列融合进行综述。     

磁共振弥散加权成像在中耳胆脂瘤精准诊断中的应用价值北大核心CSCD

目的探讨磁共振弥散加权成像(diffusion weighted imaging,DWI)联合颞骨高分辨CT(high resolution computed tomography,HRCT)定位初发中耳胆脂瘤的准确性以及对胆脂瘤术后随访复查的价值。方法选取初发胆脂瘤患者134例、疑似复发性胆脂瘤患者22例,均行HRCT、常规核磁平扫及DWI检查。以术中所见及病理诊断为基础,将DWI与HRCT图像结合,评估初发胆脂瘤病灶位置及侵袭范围与术中病变的符合度。将HRCT、DWI对复发性中耳胆脂瘤的诊断结果进行统计学分析,评估二者诊断效能。结果DWI联合HRCT定位初发胆脂瘤位置的准确率为90.3%。HRCT、DWI诊断复发性中耳胆脂瘤敏感度、特异度、阳性预测值、阴性预测值分别为27.8%、75.0%、83.3%、18.8%和100%、75.0%、94.7%、100%,与病理结果的一致性Kappa值分别为0.024和0.843,卡方配对检验证实组间诊断差异具有统计学意义(P<0.001)。结论联合DWI的高敏感度及HRCT的高分辨率,能够提高初发胆脂瘤术前定位的准确性,可用于指导手术方案的选择。DWI对复发性中耳胆脂瘤的诊断价值较高,可为二次手术探查提供参考。     

慢性化脓性中耳炎胆固醇肉芽肿6例临床观察

目的 :探讨慢性化脓性中耳炎胆固醇肉芽肿的发病机制 ,临床及影像学的诊断与鉴别。方法 :对 6例经手术和病理证实的、继发于慢性化脓性中耳炎的胆固醇肉芽肿患者的病例资料进行分析。结果 :胆固醇肉芽肿可与多种中耳疾病同时存在 ,MRI检查 T1 W与 T2 W皆为高信号。结论 :胆固醇肉芽肿的发病机制为中耳的其它疾病如胆脂瘤、硬化灶等导致的通气受阻 ,仅凭 CT及临床体征不能区别胆固醇肉芽肿与胆脂瘤 ,MRI对本病诊断有极大的价值。     

M CP -1和 FN 在中耳胆脂瘤上皮中的表达和意义

目的探讨单核细胞趋化因子（monocyte chemotactic factor ,MCP -1）和纤维连接蛋白（fibronectin , FN）在继发性中耳胆脂瘤上皮中的表达及其对胆脂瘤上皮侵袭能力的影响。方法应用免疫组织化学MaxVi-sionTM法检测MCP-1和FN在30例中耳胆脂瘤上皮、20例胆脂瘤患者耳后正常皮肤、16例非胆脂瘤患者耳后正常皮肤中的表达,应用计算机图像分析系统对其阳性表达灰度值情况及分析,比较三组之间 MCP -1和 FN表达的差异。结果 MCP-1阳性细胞表达主要分布于胆脂瘤上皮全层,其中棘层呈高表达,MCP-1在中耳胆脂瘤上皮中阳性表达率为70％,灰度值为147．2±20．1,强于胆脂瘤患者耳后正常皮肤中的阳性表达（35％,200．8±18．4）和非胆脂瘤患者耳后正常皮肤中的阳性表达（37．5％,193．3±15．5）（ P＜0．05）。FN阳性细胞主要分布于胆脂瘤上皮全层,基底层、棘层和基质呈高表达,FN在中耳胆脂瘤上皮中阳性表达率为76．7％,灰度值为139．2±18．5,强于胆脂瘤患者耳后正常皮肤中的阳性表达（30％,195．0±12．9）和非胆脂瘤患者耳后正常皮肤中的阳性表达（31．3％,191．6±13．5）（P＜0．05）。在30例中耳胆脂瘤上皮组织中,MCP-1和FN的灰度值与胆脂瘤的侵袭能力负相关（rmcp-1＝-0．682,rfn ＝-0．531,P＜0．01）,MCP-1和FN蛋白的表达不存在线性相关。结论 MCP-1和FN均在成人中耳胆脂瘤中高表达,且与中耳胆脂瘤的侵袭能力呈负相关。     

婴幼儿中耳乳突MRI异常信号影的临床分析

目的　总结分析无耳部临床表现的婴幼儿中耳乳突存在异常信号的MRI病例,探讨其诊断价值。方法  结合硬性耳内镜和1000 Hz声阻抗检查,总结分析42例（62耳）患儿无临床表现的中耳乳突存在异常信号影的MRI资料。结果　这些中耳乳突存在长T2信号影病例中,50耳可诊断为中耳炎,占80.7%;10耳提示存在一定的中耳功能障碍,占16.1%;2耳尚不能明确中耳异常长T2信号原因,占3.2%。结论　无耳部临床表现的婴幼儿中耳鼓室存在异常长T2信号的MRI患儿中有80.7%以上是与中耳炎相关,据此有助于临床制订治疗方案和疗效评估。     

HRCT常规重建与后处理对CSOM及中耳胆脂瘤诊断价值

目的探讨高分辨率CT扫描常规轴位、冠状位重建图像及图像后处理技术对慢性化脓性中耳炎及中耳胆脂瘤的诊断价值。方法对经手术病理证实并行64排螺旋CT容积扫描慢性化脓性中耳炎及中耳胆脂瘤共105例(107耳)进行回顾性分析。在常规轴位及冠状位重建图像基础上,综合运用图像后处理技术,根据主要CT表现:1、鼓室、鼓窦腔软组织密度影;2、听骨链骨质破坏情况;3、鼓室、鼓窦壁骨质破坏情况;进行术前分型,并将手术阳性结果与CT表现进行比较分析。结果慢性化脓性中耳炎59耳,其中单纯型8耳,肉芽型36耳,硬化灶肉芽型15耳;中耳胆脂瘤48耳,术前CT分型准确率为89%。对主要CT征象,常规轴位+冠状位显示率为88%,结合图像后处理技术,显示率为95%。对于所有可CT显示的术中阳性发现,均可以用多平面重组进行显示;容积再现及多平面容积再现对锤骨、砧骨破坏能较好显示,对镫骨破坏显示受到一定限制;曲面重组对面神经骨管破坏显示较满意,对听骨链骨质破坏也有一定的价值。结论 HRCT能对CSOM及中耳胆脂瘤进行较准确的术前分类、分型,常规轴位、冠状位重建图像能较全面、准确地对解剖和病变进行显示,各种图像后处理技术特别是MPR能提高CSOM及中耳胆脂瘤细微病变显示率和诊断准确率,具有很高的临床应用价值。     

P-EGFR、P-ERK和NF-κB在中耳胆脂瘤上皮中的表达和意义

目的研究磷酸化表皮生长因子受体(P-EGFR)、磷酸化细胞外信号调节激酶(P-ERK)和细胞核转录因子κB(NF-κB)在中耳胆脂瘤上皮组织中的表达情况,探讨EGFR/ERK/NF-κB信号通路在中耳胆脂瘤发病机制中的作用。方法应用免疫组织化学SP法及Western blot(WB)免疫印迹法检测30例中耳胆脂瘤标本及15例正常外耳道皮肤组织中P-EGFR、P-ERK和NF-κB蛋白的表达。结果(1)P-EGFR蛋白阳性表达主要定位于细胞质和(或)细胞膜,在胆脂瘤组的阳性表达率为63%,明显高于正常外耳道皮肤组的20%(P<0.05);P-ERK蛋白阳性表达主要定位于细胞质和(或)细胞核,在胆脂瘤组的阳性表达率为70%,明显高于正常外耳道皮肤组的20%(P<0.05);NF-κB蛋白阳性表达主要定位于细胞核,在胆脂瘤组的阳性表达率为60%,明显高于正常耳道皮肤组的13.3%(P<0.05)。在30例中耳胆脂瘤组织中,P-EGFR、P-ERK和NF-κB两两之间呈正相关关系(P<0.05)。(2)Western blot免疫印迹法检测结果显示:中耳胆脂瘤组中P-EGFR、P-ERK和NF-κB的表达量明显高于正常外耳道皮肤组的表达量。结论 P-EGFR、P-ERK和NF-κB在中耳胆脂瘤上皮中表达增强,EGFR/ERK/NF-κB信号通路可能在中耳胆脂瘤组织的形成和发展过程中起重要作用。     

PTEN及P-ERK和P-AKT在中耳胆脂瘤上皮中的表达及意义

目的：检测蛋白酪氨酸磷酸酶基因（PTEN）、磷酸化蛋白激酶B（P-AKT）和磷酸化细胞外信号调节激酶（P-ERK）在人类中耳胆脂瘤上皮的表边情况及其相关性,探讨它们在中耳胆脂瘤形成机制中的重要作用。方法：应用免疫组织化学SABC法检测40例中耳胆脂瘤标本及15例正常皮肤标本中PTEN、P-AKT和P-ERK蛋白的表达量及定位。应用Western blot免疫印迹法检测其中20例中耳胆脂瘤标本和10例正常皮肤标本PTEN、P-AKT和P-ERK蛋白以及内参GAPDH的表达量。结果：①免疫组织化学显示,PTEN在胆脂瘤和正常皮肤中的细胞核及胞质均有着色。核PTEN在胆脂瘤的阳性表达率明显低于正常皮肤,两者差异具有统计学意义（P〈O．01）;质PTEN在胆脂瘤的阳性表达率明显低于正常皮肤,两者差异具有统计学意义（P〈0．01）;P-AKT主要在细胞质着色,胆脂瘤中的阳性表达率明显高于正常皮肤,两者差异具有统计学意义（P〈0．01）;p-ERK主要在细胞核着色,胆脂瘤中的阳性表达率明显高于正常皮肤,两者差异亦具有统计学意义（P〈O．01）。在中耳胆脂瘤标本中,PTEN分别与P-AKT、P-ERK蛋白的表达之间呈显著负相关（P〈O．01）。②Western blot免疫印迹法检测显示：胆脂瘤中PTEN的表达量明显少于正常皮肤中的表达量;而P-AKT和P-ERK在胆脂瘤中的表达量明显多于它们在正常皮肤中的表达量。结论：PTEN、P-AKT和P-ERK蛋白在中耳胆脂瘤中的异常表达可能与胆脂瘤上皮的高度增殖和抗凋亡密切相关。PTEN表达缺失导致其抑制作用减弱,一方面使P-AKT表达过度,继而引起胆脂瘤上皮细胞凋亡受抑制;同时也使P-ERK表达过度,导致胆脂瘤上皮细胞增殖加强。     

PTEN、 P-Akt和NF-кB在中耳胆脂瘤上皮中的表达和意义

目的 研究10号染色体缺失张力蛋白磷酸酶(phosphatase and tensin homologue deleted on chromosome ten,PTEN)、磷酸化Akt (P-Akt)及核转录因子- κB (NF-κB)在中耳胆脂瘤上皮中的表达,探讨PI3K (phosphatidylinositol-3-kinase,磷脂酰肌醇-3激酶)- Akt信号通路在中耳胆脂瘤上皮细胞过度增殖机制中的可能作用.方法 采用免疫组织化学SP法(辣根酶标记链霉卵白素连接法,streptavidin - peroxidase conjugated method)检测30例中耳胆脂瘤组织标本与15例正常外耳道皮肤标本中PTEN、P-Akt及NF- kB蛋白的表达.结果 PTEN蛋白阳性表达主要定位于上皮细胞核,其在中耳胆脂瘤上皮中阳性表达率为36.7％,明显低于正常外耳道皮肤组的93.3％ (P＜ 0.01);P-Akt蛋白阳性表达主要定位于上皮细胞胞质,其在中耳胆脂瘤上皮中阳性表达率为70.0％,明显高于正常外耳道皮肤组的26.7％ (P＜0.01);NF- κB蛋白阳性表达定位于上皮细胞核,其在中耳胆脂瘤上皮中阳性表达率为63.3％,明显高于正常外耳道皮肤组的20.0％ (P＜ 0.01).在30例中耳胆脂瘤上皮组织中,PTEN分别与P-Akt、NF-κB蛋白的表达之间呈显著负相关(P＜0.01),而P-Akt和NF- κB蛋白的表达呈显著正相关(P＜0.01).结论 PTEN、P-Akt和NF- κB在中耳胆脂瘤上皮的异常表达可能在胆脂瘤的发生、发展过程中起重要作用.胆脂瘤上皮中PI3K-Akt信号通路的激活可能参与了胆脂瘤上皮细胞过度增殖机制.     

表皮生长因子受体和Ki67及p16在成人中耳胆脂瘤中的表达

目的:研究表皮生长因子受体(EGFR)、Ki67、p16在成人中耳继发性胆脂瘤上皮中的表达情况,分析它们之间的相互关系,探讨其表达对胆脂瘤上皮侵袭能力的影响。方法:应用免疫组织化学SP染色方法检测EGFR、Ki67和p16在30例成人中耳胆脂瘤上皮、21例成人胆脂瘤患者外耳道正常皮肤、17例正常人外耳道中的表达情况,应用计算机图像分析系统对其阳性表达进行定量分析。结果:EGFR、Ki67、p16在成人中耳继发性胆脂瘤上皮中阳性表达率分别为70.0%,60.0%,46.7%,与外耳道正常皮肤相比表达均差异有统计学意义。成人中耳胆脂瘤中EGFR、Ki67与p16之间表达均无相关性(均P>0.05)。胆脂瘤侵袭能力与EGFR、Ki67表达有显著相关性(均P<0.01)。EGFR、Ki67表达灰度值越低,表达密度越高,胆脂瘤侵袭能力越强。p16在成人中耳胆脂瘤中的表达与侵袭能力之间无相关性(P>0.05)。EGFR、Ki67、p16在成人中耳胆脂瘤中阳性细胞主要分布于上皮全层,以基底层和棘层为著,呈高度表达;而在对照组中阳性细胞仅在基底层表达,呈弱表达。结论:EGFR、Ki67、p16在成人中耳胆脂瘤中呈高表达,EGFR、Ki67的表达与成人中耳胆脂瘤的侵袭能力有高度相关性,提示成人中耳胆脂瘤具有高度增殖能力,其中细胞因子EGFR、Ki67、p16起到重要的作用。     

Usefulness of delayed postcontrast magnetic resonance imaging in the detection of residual cholesteatoma after canal wall-up tympanoplasty

OBJECTIVES/HYPOTHESIS: Imaging takes an increasing place in the follow-up of patients who have undergone surgery for cholesteatoma, with computed tomography (CT) as the first line imaging technique. However, in case of complete opacity of the tympanomastoid cavities, CT is not able to differentiate residual cholesteatoma from postoperative scar tissue. The aim of this study was to assess the usefulness of magnetic resonance imaging (MRI) using delayed postcontrast T1-weighted images for the detection of residual cholesteatoma after canal wall-up tympanoplasty (CWU) in cases where CT was not conclusive. STUDY DESIGN: Prospective study. METHODS: MRI, with delayed postcontrast T1-weighted images (30-45 minutes after contrast injection), was performed before revision surgery in 41 consecutive patients who had undergone CWU for cholesteatoma and presenting with a nonspecific complete opacity of the mastoid bowl on CT. In all the cases, imaging results were compared with operative findings at surgical revision. RESULTS: A residual cholesteatoma was found in 19 of 41 patients at revision surgery and was correctly detected on MRI in 17 patients. In the two remaining cases, cholesteatoma pearls smaller than 3 mm were not seen. There was no false-positive case. Statistics were as follows: sensitivity 90%; specificity 100%; positive predictive value 100%; negative predictive value 92%. CONCLUSION: When postoperative CT is not conclusive because of complete opacity of the tympanomastoid cavities, MRI with delayed postcontrast T1-weighted images is a reliable additional technique for the detection of a residual cholesteatoma when its diameter is at least 3 mm.     

Value of diffusion-weighted MR imaging in the detection of middle ear cholesteatoma

OBJECTIVE: This study, was conducted to determine the clinical value of diffusion-weighted MR imaging (DWI) in detecting the presence of cholesteatoma. SUBJECT AND METHODS: Fifty-six patients (21 female and 35 male patients; mean age, 43 years) who underwent middle ear surgery were referred to the radiology department for a preoperative DWI study. RESULTS: DWI depicted 41 out of 48 cholesteatomas involving the middle ear cavity (sensitivity, 85.4%). Seven patients with middle ear cholesteatoma who showed negative DWI findings (false-negative cases) had limited keratin accumulation due to simple atelectasis or meticulous evacuation of keratin debris before the MRI study. No falsepositive cases were found in this study (specificity, 100%). The positive predictive value and negative predictive value were 100% and 53.3%, respectively. The minimum size of middle ear cholesteatoma detected by the current MRI system was 5mm. CONCLUSION: Diffusion-weighted MR imaging was useful for the detection of middle ear cholesteatoma.     

Efficacy of diffusion-weighted magnetic resonance imaging in the diagnosis of middle ear cholesteatoma

Objective

This study evaluated the usefulness of diffusion-weighted magnetic resonance imaging (DWI) in the diagnosis of middle ear cholesteatoma.

Methods

We performed DWI on 73 patients suspected of having middle ear cholesteatoma, including 21 revision cases. Magnetic resonance imaging was performed with 1.5 T units using diffusion-weighted spin-echo-type echo planar imaging (DWI).

Results

Of 73 subjects, 59 had cholesteatoma that consisted of 41 primary acquired cholesteatoma, 13 had residual and/or recurrent cholesteatoma, four had congenital cholesteatoma, and one had iatrogenic cholesteatoma. Positive DWI findings were observed in 42 subjects and negative findings in 31 subjects. The sensitivity, specificity, and positive and negative predictive values of DWI for cholesteatoma were 69.4%, 92.8%, 97.5%, and 41.9%, respectively. In the case of 34 patients who were positive for cholesteatoma on both otoscopic and CT examinations, 33 were diagnosed with cholesteatoma. Of the remaining 39 subjects with one or both negative results for cholesteatoma, the sensitivity, specificity, positive predictive value, and negative predictive value of DWI were 57.6%, 92.3%, 93.7%, and 52.1%, respectively. Cholesteatoma mass diameters were less than 5 mm in 10 out of 18 subjects with both cholesteatoma and negative DWI findings. Of the 21 subjects who received revision surgery, the sensitivity, specificity, and positive and negative predictive values of DWI for residual or recurrent acquired cholesteatoma were 71.4%, 100%, 100%, and 63.6%, respectively.

Conclusions

Since DWI clearly showed high specificity and positive predictive value, it is useful for diagnosing middle ear cholesteatoma, including postoperative recurrent cholesteatoma of 5 mm diameter or larger. DWI could sufficiently detect cholesteatoma with one or both negative results on otoscopic and CT examinations, but it was difficult to detect cholesteatoma of less than 5 mm diameter using DWI owing to the tiny mass and small volume of debris.     

Non-echoplanar diffusion weighed imaging and T1-weighted imaging for cholesteatoma mastoid extension

ObjectivesA broad mastoid extension limits cholesteatoma resection via a transmeatal approach including endoscopic ear surgery. Therefore, a preoperative diagnosis of mastoid extension is a the most critical factor to determine whether to perform mastoidectomy. The purpose of this study was to assess the efficacy of non-echoplanar diffusion-weighted imaging (non-EPI DWI) and T1-weighted imaging in the evaluation of mastoid extension in cholesteatomas of the middle ear.MethodsPatients who underwent magnetic resonance imaging (MRI) for pretreatment evaluation before primary surgery for pars flaccida or tensa cholesteatoma, which revealed a high-signal intensity in the mastoid on T2-weighed imaging were retrospectively evaluated. Two board-certified radiologists retrospectively evaluated the extent of cholesteatomas on MRI with non-EPI DWI, non-EPI DWI- and T1-weighted axial imaging. The presence of a high signal intensity on non-EPI DWI or low or high signal intensity on T1-weighted imaging in the mastoid was evaluated. All cases were subclassified as M+ (surgically mastoid extension-positive) or M- (surgically mastoid extension-negative).ResultsA total of 59 patients with middle ear cholesteatoma were evaluated. There were 37 M+ cases and 22 M- cases. High-signal intensity on non-EPI DWI exhibited a sensitivity of 0.89 and specificity of 0.82, whereas partial low-signal intensity on T1-weighted imaging exhibited a sensitivity of 0.84 and specificity of 0.91 for detecting mastoid involvement. Complete high-signal intensity on T1-weighted imaging exhibited a sensitivity of 0.73 and specificity of 0.89 for detecting non-involvement of the mastoid. The sensitivity (0.92) and specificity (0.96) of combined non-EPI DWI and T1-weighted imaging evaluation were higher than those of with non-EPI DWI or T1-weighted imaging alone. The interobserver agreement for the presence of high-signal intensity in the mastoid cavity on non-EPI DWI was very good at 0.82, that of a partial low-signal intensity area in the mastoid cavity lesions on T1-weighted imaging was good, at 0.76 and that of complete high-signal intensity in the mastoid cavity lesions on T1-weighted imaging was good, at 0.67.ConclusionsThe signal intensity on non-EPI DWI and T1-weighted imaging of the mastoid could be used to accurately assess the extent of middle ear cholesteatoma, which could facilitate surgical treatment planning.     

Diffusion-weighted MR imaging for evaluation of pediatric recurrent cholesteatomas

Objective

To compare the efficiency of diffusion-weighted MR imaging (MRI) vs. high resolution CT in predicting recurrent or residual cholesteatoma in children who underwent prior middle ear surgery.

Design

Prospective study.

Setting

Tertiary care university hospital.

Patients

Seventeen patients (4 with 2 recurrences) aged 5-17 years (mean 11.4) previously surgically treated for a cholesteatoma of the middle ear, were included for follow-up with systematic CT scan and MRI, between 2005 and 2007.

Methodology

CT scan was performed on a Siemens Somaton 64 (0.5/0.2 mm slices reformatted in 0.5/0.3 mm images), parallel and perpendicular to the lateral semi-circular canal for each ear (100 mm × 100 mm FOV). MRI was undertaken on a Siemens Avanto 1.5 T unit, with an adapted protocol for young children. Diagnosis of recurrent cholesteatoma was based on the evidence of a hyperintense image at B1000 on diffusion-weighted images. Results of CT scan and MRI were compared with operative diagnosis.

Results

Nine patients had a positive MRI, among which 8 had cholesteatoma confirmed during revision surgery. In the 12 negative MRI cases, 5 were positive on revision surgery. None of these lesions was over 3 mm. Two of them were diagnosed on the CT scan. CT scan alone had a positive predictive value of 75%, and a negative predictive value of 58%.

Conclusion

Diffusion-weighted MRI is associated with a high positive predictive value for the detection of recurrent cholesteatoma. CT scan remains the first choice imaging technique. In case of doubtful CT scan, diffusion-weighted MRI could confirm a recurrence or, when negative, avoid second-look surgery.     

Predictive validity of MRI in detecting and following cholesteatoma

High recurrence rate of the middle ear cholesteatoma requires regular postoperative follow-up. This study evaluated data from the patients investigated with DW MRI to ascertain (1) the strength of the technique in detecting primary, and residual recurrent cholesteatoma, and (2) its accuracy in differentiating cholesteatoma from postoperative tissue changes. The diagnostic accuracy of two different DW imaging (EPI and non-EPI) techniques was evaluated. The data have been collected prospectively from 33 consecutive patients with either primary cholesteatoma, or with suspicious symptoms for potential cholesteatoma recurrence. The findings from non-EPI (HASTE) DW MR and EPI DW MR images were blindly compared with those obtained during a primary or secondary surgery. Preoperative non-EPI (HASTE) DWI pointed to a cholesteatoma in 25 out of 33 patients. In this subgroup, cholesteatoma were confirmed also by the surgery. In five cases, the non-EPI (HASTE) DWI did not show a cholesteatoma in the temporal bone, which agreed with the surgical findings. Three misclassifications were made by non-EPI (HASTE) DWI, all in the subgroup of patients indicated for primary surgery. The resulting pooled sensitivity of non-EPI (HASTE) DW imaging for diagnosing cholesteatoma in our study amounted to 96.15% (95% confidence interval (CI) 80.36–99.9), specificity was 71.43% (95% CI 29.04–96.33). Positive predictive value was 92.59% (95% CI 75.71–99.09) and negative predictive value 83.33% (95% CI 35.88–99.58). In conclusion, we recommend the non-EPI (HASTE) DW MRI as a valid method for diagnosing cholesteatoma and follow-up after cholesteatoma surgery.     

Postoperative diffusion weighted MRI and preoperative CT scan fusion for residual cholesteatoma localization

ObjectiveTo evaluate the ability of preoperative mastoid high resolution Computerized tomography (CT Scan) fusion with the postoperative diffusion weighted magnetic resonance imaging (Non-EPI DWI) to accurately localize the residual cholesteatoma thus sparing an unnecessary postoperative CT scan radiation.Patients and methodsthis is a prospective study performed in our tertiary care center. We followed up prospectively a consecutive group of patients presenting with middle ear cholesteatoma using preoperative mastoid CT scans, postoperative mastoid CT scan and mastoid diffusion weighted MRI (DWI) between 2012 and 2013. Postoperative DWI were fused to both: the preoperative and postoperative mastoid CT scans. Fused images were evaluated for their ability to detect accurately the location of residual cholesteatoma if any. Results were correlated to the surgical findings.ResultsTwenty-eight patients were included in this study. Ten patients showed middle ear opacity on the postoperative CT scans; the remaining negatively patients were excluded. DWI detected residual cholesteatoma in 3 out of the ten patients. Both CT scans; the pre and postoperative were able to precisely localize the residual cholesteatoma when fused to the postoperative DWI. Intra-operatively, three patients had a residual cholesteatoma that corresponded to the fused radiological images while a fourth patient presenting low signal intensity on the Non-EPI DWI had no cholesteatoma.ConclusionDiffusion weighted MRI/CT scan fusion combines the advantages of residual cholesteatoma detection and precise localization. Preoperative CT scans performed before the first surgery can be used for the fusion with the Non-EPI DWI in order to spare the patient an unnecessary another CT scan and thus decreasing radiation exposure.     

Benign mass lesions deep inside the temporal bone: imaging diagnosis for proper management

CONCLUSION: Among mass lesions inside the temporal bone, benign tumors and cholesteatomas can be differentiated by contrast enhancement in T1-weighted images (T1WI) and by diffusion-weighted images (DWI). Moreover, DWI will also facilitate discrimination between cholesteatomas accompanied by granulation and other non-neoplastic lesions such as mucoceles and cholesterol granulomas. OBJECTIVES: To review the imaging characteristics of mass lesions inside the temporal bone and to investigate pertinent imaging modalities for differential diagnosis, which is crucial for appropriate treatment planning. PATIENTS AND METHODS: This was a retrospective case series study of six patients seen between 2002 and 2005 with mass lesions deep inside the temporal bone. RESULTS: One patient had facial schwannoma, two had glomus jugulare tumor, and three had cholesteatoma. Plain high resolution CT gave few clues to the nature of the mass lesions. MRI study provided us with better clues: contrast enhancement on T1WI was observed only in benign tumors and only cholesteatomas showed high intensity on DWI. With the assistance of neurosurgeons, surgery was successfully performed in all cases.     

Value of high-resolution computed tomography and magnetic resonance imaging in the detection of residual cholesteatomas in primary bony obliterated mastoids

PURPOSE: The objective of this study was to assess the value of high-resolution computed tomography (HRCT) and that of magnetic resonance imaging (MRI), including postcontrast T(1)-weighted images and echo-planar diffusion-weighted (EP-DW) images, in the detection of residual cholesteatomas after primary bony obliteration of the mastoid. PATIENTS AND METHODS: Twenty-three patients underwent a second-look surgery 8 to 18 months after they underwent a primary bony obliteration technique. All patients were evaluated by HRCT and MRI before their second-look surgery. A retrospective analysis was performed. RESULTS: A residual cholesteatoma was found in 2 of the 23 patients; both cases of cholesteatoma had a diameter less than 4 mm. In these 2 patients, residual cholesteatoma was found in the middle ear cavity and not in the obliterated mastoid. In all cases, HRCT showed a homogeneous obliteration of the mastoid cavity. On MRI, only one cholesteatoma pearl was detected using contrast-enhanced T(1)-weighted imaging. Findings from the EP-DW imaging were negative for all cases. CONCLUSION: This study demonstrates that HRCT is still the imaging technique of choice for the evaluation of bony obliterated mastoids. It shows the low sensitivity and specificity of HRCT for the characterization of an associated opacified middle ear and those of contrast-enhanced T(1)-weighted imaging and EP-DW imaging for the detection of small residual cholesteatomas after primary bony obliteration.