先天性内耳发育畸形的多层螺旋CT表现

目的 探讨先天性内耳发育畸形的多层螺旋CT表现。资料与方法 回顾性分析17例（32耳）先天性内耳发育畸形患者的CT表现,所有患者均做多层螺旋CT横断面扫描及多平面重建,对患耳做单侧重叠放大重建,并利用容积再现技术（VRT）对骨迷路进行三维重建。结果 本组先天性内耳发育畸形有以下几种：（1）Michel型（1耳）：内耳结构完全缺如。（2）共同腔畸形（2耳）：耳蜗和前庭呈一囊状结构,二者不能相互区分。（3）不完全分隔Ⅰ型（3耳）：耳蜗缺乏完整的蜗轴,呈囊状改变,同时前庭扩大呈囊状。（4）不完全分隔Ⅱ型（Mondini型）（4耳）：耳蜗仅1．5圈,中圈和顶圈融合,前庭扩大。（5）前庭及半规管畸形（14耳）：耳蜗正常,前庭扩大,半规管短小、粗大或缺如。（6）前庭导水管扩大（14耳,其中6耳伴随其他畸形）：前庭导水管扩大呈喇叭口状或与总脚相通。（7）内耳道畸形（8耳均伴随其他畸形）：内耳道缺如、狭窄或扩大。结论 先天性内耳发育畸形有其特殊的形态学表现,多层螺旋CT扫描结合后处理成像可清晰显示各种畸形的二维和三维解剖特征,对诊断有重要价值。     

内耳骨迷路畸形的HRCT表现

目的 探讨先天性内耳骨迷路畸形的高分辨率CT（HRCT）特征。资料与方法 回顾分析28例（56耳）先天性感音性耳聋的内耳骨迷路畸形患者HRCT表现。结果 Michel畸形1耳,囊状耳蜗．前庭畸形（IP-1畸形）8耳,Mondinl畸形（IP-2畸形）17耳,耳蜗未发育4耳,耳蜗发育不全6耳,共腔畸形4耳,前庭．外半规管畸形8耳,前庭导水管扩大8耳。结论 HRCT可显示先天性内耳畸形表现,为内耳畸形的诊断和人工耳蜗植入术适应证的选择提供了依据。     

MSCT和MRI对人工耳蜗植入术前的评价

目的:探讨MSCT和MRI对人工耳蜗植入术前的评价方法及其临床价值。方法:对43例拟行人工耳蜗植入术的患者行MSCT和MRI检查,分析其影像学表现,指导临床选择适应证和植入耳侧。结果:43例中20例MSCT和MRI均未发现异常,23例(42耳)MSCT和MRI均发现有异常,其中先天性内耳发育畸形20例39耳:①MicheⅠ型1耳,表现为内耳结构完全缺如;②共同腔畸形3耳,耳蜗和前庭融合呈一囊状结构;③不完全分隔Ⅰ型(IP-Ⅰ型)3耳,耳蜗和前庭均呈囊状,两者轮廓可以区分;④Mondini型5耳,耳蜗仅1.5圈,中圈和顶圈融合,前庭扩大;⑤前庭与半规管畸形13耳:耳蜗正常,前庭扩大,半规管短小、粗大或缺如;⑥前庭导水管扩大14耳,前庭导水管扩大呈喇叭口状或与总脚相通。骨化性迷路炎3例3耳,MSCT表现为内耳迷路内密度不同程度增高,MRI表现为迷路信号减低。MRI显示蜗神经缺如5耳,蜗神经细小2耳。结论:术前MSCT和MRI检查相互补充,应作为常规术前检查。MSCT在显示中耳结构和立体显示内耳畸形的形态方面优于MRI,可指导手术方案的制定和判断预后,MRI对于评价听神经是否正常有重要价值。     

前庭导水管扩大的CT表现(附72例报告)

目的：对７２例前庭导水管扩大患者ＣＴ表现进行了分析，并估计合并其他内耳发育畸形的比例，材料与方法：７２例均行横断面ＣＴ扫描，２０例并行冠状面扫描，结果：单纯前庭导水管扩大４１耳（３０．４％）合并前庭及外半规管发育不良５８耳（４２．９％），合并前庭，半规管，耳蜗及内耳道发育不全３６耳（２６．７％），结论：前庭导水管扩大是较为常见的一种内耳迷路发育畸形，最常合并能前庭及外半规管发育畸形。     

16排螺旋CT对先天性内耳发育畸形的诊断价值

目的 探讨16排螺旋CT对先天性内耳骨迷路发育畸形的诊断价值.方法 105例感音神经性耳聋患者接受16排螺旋扫描,取层厚0.625 mm,Bone Plus骨算法,单侧DFOV 9.6 cm或7.5 cm放大重建,行MPR和VR重建.结果 105例患者中有75例150耳CT显示正常,30例56耳为先天性内耳畸形,包括骨迷路未发育(Michel畸形)4例5耳,耳蜗未发育1例1耳,共腔畸形3例5耳,阶间隔Ⅰ型(囊状耳蜗-前庭畸形)1例1耳,耳蜗发育不全3例4耳,阶间隔Ⅱ型(Mondini畸形)12例21耳,前庭-半规管畸形5例9耳,前庭导水管扩大15例27耳,内耳道畸形12例19耳及内耳骨迷路畸形伴颈静脉球高位10例15耳.结论 多排螺旋CT检查对先天性内耳骨迷路发育畸形的诊断具有重要价值.     

顺序和针对性图像分析方法诊断内耳畸形

目的:探讨内耳畸形的颞骨CT诊断和术前评价意义。方法:采用顺序性和针对性图像观察方法回顾性分析26例内耳畸形的颞骨CT表现.与原诊断报告的描述进行比较,并进行一致性检验。结果:26例(共52侧耳)内耳畸形患者中耳蜗发育不全15例、前庭导水管扩大19例、半规管发育不良和前庭扩大11例,这4种畸形单发或联合者占所有骨迷路畸形的80%。原诊断报告中主要遗漏了半规管发育不良4侧耳、前庭导水管扩大7侧耳、耳蜗发育不全6侧耳。采用顺序性图像观察方法,两位阅片者诊断内耳畸形的Kappa值为0.97;与原诊断报告的Kappa值分别为0.51和0.55。人工耳蜗植入术前评价发现耳蜗及前庭与内听道底部骨质缺损17侧耳、半规管骨壁缺损2侧耳、面神经管迷走6侧耳。结论:高分辨力颞骨CT扫描对详细了解内耳畸形的程度、部位及类型具有重要意义。采用顺序性观察方法可避免内耳畸形的漏诊;针对性的评价对充分做好人工耳蜗植入术前准备具有指导意义。     

磁共振内耳成像在先天性内耳发育畸形中的诊断应用

目的:探讨磁共振内耳成像在先天性内耳发育畸形中的临床应用价值。方法:18例先天性感音神经性耳聋患者行MRI扫描并进行后处理,主要方法包括多平面重组(MPR)、最大密度投影(MIP)及客积再现技术(VRT)。结果:18例34耳存在内耳畸形。1例2耳Michel畸型;2例3耳共同腔畸形;4例8耳Mondini畸型;8例16耳前庭导水管扩大;3例5耳显示内听道畸形。MRI MPR、MIP及VRT重组图像可以清晰地显示内耳畸形的部位和程度。结论:磁共振内耳成像能清楚、立体显示正常膜迷路和内听道内神经结构,对于内耳畸形的诊断及人工耳蜗植入术前评价有重要价值。     

螺旋CT实时三维成像显示内耳结构方法初探

目的：探讨螺旋CT RT－3D成像显示内耳结构的方法。资料与方法：对12例颞骨进行螺旋CT扫描，并利用RT－3D成像，层厚1mm，螺距1．0，0．1mm密集重建。结果：12例24耳耳蜗呈蜗牛状22耳，前庭呈囊状，水平半规管、上半规管及后半规管显示良好，半规管总脚及膨大的壶腹均显示良好；1例2耳耳蜗、前庭及半规管融合成囊状，类似倒“逗号”状。22耳蜗神经、前庭神经显示良好，其中2耳蜗神经较细；1例左侧内听道狭窄，蜗神经管变细；24侧面神经膝段均清晰显示，面神经鼓室段4例8耳显示良好，面神经乳突段与周围乳突气房分辨差。结论：螺旋CT RT－3D成像能清晰显示内耳结构，方法简单，易于操作，可以多方位观察。     

内耳畸形的影像学诊断

内耳，又称迷路，位于颞骨岩部，位置深在，结构细小复杂，可分为耳蜗、前庭、前庭导水管、半规管、内耳道。过去内耳一直是影像学检查的盲区，X线平片无法显示其详细结构。高分辨率CT（HRCT）颞骨薄层扫描，能够清晰显示内耳的细微骨结构，螺旋CT三维重建还可将轴位的二维原始图像转换成三维立体图像，对内耳结构的显示更为直观，但只限于骨结构。     

64排CT三维透明化重组在内耳畸形诊断中的应用

目的探讨三维透明化重组在内耳畸形诊断中的应用价值,为先天性内耳疾病提供准确的影像诊断和临床治疗信息。资料与方法回顾32耳内耳畸形的64排高分辨率CT(HRCT)容积数据,行三维透明化重组处理,按内耳畸形分类总结三维透明化重组方法及影像表现。结果 32耳的三维透明化容积再现(VR)图像结合透明化多平面重组(MPR)图像均能很好揭示内耳畸形病变部位及程度,内耳病变整体显示方面及蜗窗、前庭窗、半规管等细节病变显示中透明化VR像及透明化MPR像明显优于轴位像及普通MPR像;在耳蜗内部结构的显示中,透明化MPR、轴位像及普通MPR像优于透明化VR像。32耳先天内耳发育畸形有以下几种:耳蜗未发育(2耳);共同腔畸形(4耳);不完全分隔Ⅰ型(2耳,2例患者对侧耳均为共同腔畸形);不完全分隔Ⅱ型(即Mondini型)(16耳,多合并前庭、半规管及前庭导水管畸形);单纯前庭-半规管畸形(2耳);单纯前庭导水管扩大(6耳)。结论三维透明化个性重组能准确评价内耳先天性疾病的类型和程度,为临床治疗提供重要的参考依据。     

Stress MR imaging for evaluation of popliteal artery entrapment

The popliteal artery entrapment (PAE) syndrome has been recognized as a cause of arterial occlusion in young people. It is the result of an anomaly of the relationship between the popliteal artery and the gastrocnemius muscle. Eight young healthy volunteers (16 legs) and six patients (10 legs) with suspected PAE underwent magnetic resonance (MR) imaging. Gradient-echo images were obtained in axial planes with the leg at rest and during active plantar flexion against resistance. Imaging at rest allowed identification of PAE signs in only one leg, which had an anomalous medial course of the popliteal artery. In the other cases, only the stress technique was able to show signal loss in the popliteal artery due to muscular compression (two legs) or the presence of accessory muscle slip around the vessel (two legs), as confirmed at surgery. MR imaging is therefore a useful technique for the diagnosis of PAE because of its capability of combining information obtainable with other modalities.     

MR imaging of muscle and tender points in fibromyalgia

Fibromyalgia is a syndrome manifested by chronic, diffuse muscu-loskeletal aching and soreness, palpable muscle tender points, and other symptoms. Standardized clinical diagnostic criteria have recently been developed. Skeletal muscle has been postulated as the end organ in this disease. Biochemical, histologic, electromyographic, and conventional radiographic studies have demonstrated no definitive abnormality. This study sought to establish whether magnetic resonance (MR) imaging could demonstrate any abnormality in these patients. Eighteen patients were entered in the study, 14 of whom were able to complete their examinations. T1 -weighted, T2-weighted, gradient-echo, and STIR (short-tau inversion-recovery) sequences were performed in all patients, with selected patients examined with T1weighted, gadopentetate dimeglu-mine-enhanced sequences. The trapezius and suboccipital regions were imaged in patients who, clinically, had active fibro-myalgia. No abnormalities could be detected. The authors conclude that the conventional MR imaging used in this study was unable to depict any primary skeletal muscle abnormality in fibromyalgia.     

Uterine contractions: Possible diagnostic pitfall at MR imaging

A total of 206 nongravid patients with various gynecologic problems underwent pelvic magnetic resonance (MR) examinations that included both sagittal T2-weighted and contrast agent–enhanced T1-weighted images. MR images were retrospectively reviewed to identify changes in endometrial configuration on serial images obtained during the same MR examination. In 20 MR examinations (all in women of reproductive age), endometrial distortion due to myometrial bulging was noted on T2-weighted or contrast-enhanced T1-weighted images. It was absent on other MR images obtained at different times. Myometrial bulging exhibited low signal intensity in 18 examinations. The finding resembled adenomyosis or leiomyoma on T2-weighted or contrast-enhanced T1-weighted images. These results evidence the presence of transient myometrial bulging and transient low-intensity myometrium in the nongravid uterus. This phenomenon is thought to represent uterine contraction. Clinicians should be aware of the potential presence of transient low-signal-intensity myometrial bulging that could present diagnostic problems in the normal uterus.     

Controversies in cervical spine imaging in trauma patients

No area of emergency radiology has generated as much discussion in recent years as the subject of cervical spine imaging for trauma patients. This review will be in three parts. The first will examine the indications for cervical imaging and will focus on those factors that make patients at high risk or low risk for cervical injury. The second part will discuss the merits of radiography and computed tomography as the main screening diagnostic examination. In addition to the roles of each modality in the evaluation process, such factors as efficacy of diagnosis, time (duration) of study, and cost will be discussed. Finally, the third part will explore the methods currently employed to clear the cervical spine in comatose patients.Presented at the Annual Meeting of the American Society of Emergency Radiology, Las Vegas, Nevada, 22–25 October, 2003     

Brodie Abscess: MR imaging appearance in 10 patients

The magnetic resonance (MR) imaging features of Brodie abscess have not yet been fully evaluated. Ten patients with Brodie abscess, eight of long bone and two of vertebra, were studied with MR imaging. Long bone abscess had a characteristic “target” appearance with four layers: (a) a center with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR (short-inversion-time inversion recovery) images, (b) an inner ring isointense to muscle on T1-weighted images and with high signal intensity on T2-weighted and STIR images, (c) an outer ring hypoin-tense on all images, and (d) a peripheral halo hypointense on T1-weighted images. In six of eight cases, a soft-tissue mass was found. The two vertebral abscesses had a less specific appearance, with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR images. Only the peripheral halo was clearly identified in both cases.     

Dynamic contrast-enhanced MR imaging assessment of vascularized free fibular grafts

Magnetic resonance (MR) imaging may be a noninvasive method for assessing perfusion of vascularized bone grafts placed for treatment of avascular necrosis. One proximal femur of seven beagles was devascularized, with insertion of a vascularized fibular graft. MR imaging at 1 week (seven dogs) and 6 weeks (five dogs) after surgery included pre- and postcontrast spin-echo sequences, unenhanced twodimensional time-of-flight (TOF) vascular imaging, and dynamic gradient-echo imaging during infusion of gadolinium. Relative signal intensity values of selected regions obtained from the dynamic gradientecho images were plotted as percent enhancement versus time. In the operated hip, MR imaging did not show enhancement in six of seven femoral heads and greater trochanters at 1 week after surgery, with similar results after 6 weeks. MR imaging of fibular grafts 6 weeks after surgery showed an initial rapid increase in enhancement and a subsequent slower increase in five of five dogs, although no enhancement was seen in six of seven dogs at 1 week. These findings contrasted with a rapid initial increase in enhancement followed by slow decline in non-operated hips. Two-dimensional TOP imaging did not show the vascular pedicle of the graft in any dog. Findings of radionuclide bone scanning performed 1 week after surgery were consistent with devascularization of the operated femur and fibular graft. However, tetracycline distribution and histologic findings confirmed the viability of five of five grafts within the devascularized femurs 6 weeks after surgery. Thus, dynamic contrast-enhanced MR imaging at 6 weeks after surgery is valuable for assessing vascular bone graft perfusion, while similar imaging at 1 week may suggest otherwise.     

Right-side aortic arch with aneurysm of aberrant left subclavian artery: MR imaging appearance.

Reports of aneurysms of the subclavian artery in both normal and anomalous aortic arches have been rare. The authors describe a patient with a right-side aortic arch and an aneurysm of the aberrant left subclavian artery, which, to the authors' knowledge, is a previously unreported association. At presentation, the aneurysm appeared as a calcified left superior mediastinal mass. Magnetic resonance imaging enabled preoperative diagnosis and guided surgical planning.     

Adrenal tissue characterization with 0.5-T MR imaging: Value of T2*-weighted images

The authors investigated the value of magnetic resonance (MR) imaging at 0.5 T for distinguishing adrenal adenomas from adrenal metastases. The series included 23 adrenal adenomas (18 nonhyperfunctioning, five hyperfunctioning) and 23 adrenal metastases from various organs. Adrenal tumor–liver signal intensity ratios on T1-, T2-, and T2*-weighted images were calculated for adrenal tissue characterization. Adrenal adenomas were more precisely distinguished from adrenal metastases on T2*-weighted images (21 of 23, 91%) than on T2-weighted images (15 of 23, 65%). T1-weighted images were not useful for this distinction. In conclusion, T2*-weighted images were better than routine T2-weighted images for distinguishing adrenal adenomas from adrenal metastases. It can be postulated that the total signal intensity of adrenal adenomas, which contain some fat components, decreased on T2*-weighted images because of an out-of-phase effect.     

MR angiography of congenital heart disease: Value of segmented two-dimensional inflow technique and maximum-intensity-projection display

Magnetic resonance (MR) angiography of the cardiovascular system was evaluated in 41 patients with congenital heart disease by using a two-dimensional (2D) inflow technique based on a magnetization-prepared gradient-echo pulse sequence with segmented k-space data acquisition and electrocardiographic gating at 0.5 T. Inversion and saturation prepulses were used to suppress stationary tissue and enhance intravascular signal. Presaturation slabs were applied where certain vascular structures had to be suppressed. Sequence parameters were optimized by evaluating signal intensity and contrast characteristics for various flip angles and inversion and saturation delay times. The heart and intrathoracic vasculature were encompassed with 40–50 overlapping sections. Both 2D angiograms and maximum-intensity-projection images were evaluated. Combining data sets acquired in the sagittal and transverse orientations provided the most satisfactory information about the pulmonary arteries. The highest signal-to-noise ratios were obtained with a flip angle of 65° and short prepulse delay times. Two-dimensional MR angiography can provide useful diagnostic information but requires a thorough understanding of in-plane and hemodynamically induced signal intensity changes.