肾上腺神经鞘瘤的CT诊断

目的：通过对肾上腺神经鞘瘤的病理及CT表现分析,结合复习国内外文献,提高对肾上腺神经鞘瘤影像诊断的能力。方法：回顾本院所遇经手术病理证实的4例肾上腺神经鞘瘤CT特征和病理学表现。结果：3例肿块位于右肾上极前与下腔静脉后间隙中,在平扫上呈圆形或卯圆形低密度肿块,其边缘清晰锐利。肿瘤内部密度不均,1例内见点状钙化灶,增强扫描肿块呈轻度不均匀强化。1例位于左侧肾上腺外侧支,呈圆形略分叶状的均匀等密度结节,增强后肿块表现为中度强化。结论：CT对肾上腺神经鞘瘤的定位,及肿瘤的诊断与鉴别诊断有一定的价值。     

肾上腺神经鞘瘤的 CT 表现

目的：分析原发性肾上腺神经鞘瘤的 CT 影像学特征。方法收集6例经病理确诊为肾上腺神经鞘瘤患者的临床及影像学资料。结果6例均表现为边界清楚,类圆形或类椭圆形不均质囊实性肿块。其中2例见钙化,3例见分隔。在增强扫描上,肿物均表现为延迟强化。结论肾上腺神经鞘瘤一般表现为边界清楚、密度不均质的类圆形肿块,多合并囊变,分隔及钙化,强化方式多为延迟强化,具有一定的特征性。     

Cystic schwannoma mimicking adrenal tumor

The CT and ultrasound findings in a case of cystic schwannoma mimicking a left adrenal tumor are reported. The differential diagnosis of cystic lesions arising in the adrenal region is discussed.     

肾上腺少见肿瘤的超声表现

目的探讨肾上腺少见肿瘤的超声声像图特征,提高对该类疾病的认识水平。方法收集18例经手术和病理证实的肾上腺少见肿瘤,对其超声表现进行回顾性分析。结果神经鞘瘤5例,均呈低回声,其中4例伴囊性无回声区;畸胎瘤4例,内部混杂细密点状高回声和强回声;血管瘤4例,其中2例内部呈混合性回声伴散在点状强回声,另2例呈低回声;Castleman病3例,内部呈低回声,边界清晰,团块后方回声增强;淋巴管血管瘤2例,其中1例呈分叶状内部为低回声,另1例内部呈囊性无回声,边缘可见条状强回声。结论超声对肾上腺少见肿瘤定位及定性提示有一定价值,结合超声表现与l临床及其它影像学检查,可提高肾上腺少见肿瘤术前诊断的准确性。     

Adrenal schwannoma: CT and MRI findings

We report a case of adrenal schwannoma, an extremely rare retroperitoneal neoplasm. The patient was a 33-year-old man who presented with an abdominal mass that was discovered at abdominal sonography. Computed tomography showed an 8-cm well-circumscribed homogeneous mass that enhanced slightly after intravenous administration of contrast material. Magnetic resonance imaging showed low signal intensity on T1-weighted images and heterogeneously high signal intensity on T2-weighted images. Although these imaging findings are nonspecific, adrenal schwannomas should be included in the differential diagnosis of solid nonfunctioning adrenal tumors.     

MR扩散加权成像对桥小脑角区实性神经鞘瘤与脑膜瘤的鉴别诊断价值

目的：探讨 MR扩散加权成像(DWI)及表观扩散系数(ADC)在桥小脑角区实性神经鞘瘤与脑膜瘤鉴别诊断中的价值。方法回顾性分析经术后病理证实的桥小脑角区12例实性神经鞘瘤和27例脑膜瘤的 DWI 图像,逐层勾画肿瘤边界以获得整体感兴趣区(ROI),得到肿瘤的平均 ADC 值(mADC)。同时以脑干 mADC 值为参考,计算得到肿瘤/脑干 ADC 比值(ADC ratio, rADC=肿瘤 mADC值/脑干 mADC值)。桥小脑角区实性神经鞘瘤和脑膜瘤之间的 mADC 和 rADC 值差异采用独立样本t检验分析。采用受试者工作特征曲线(ROC)分析 mADC 和 rADC 值在两者鉴别诊断中的价值。结果桥小脑角区实性神经鞘瘤mADC和 rADC值均明显高于脑膜瘤(mADC,P=0.001;rADC,P=0.002)。以 mADC=0.994×10-3 mm2/s 作为诊断阈值,鉴别实性神经鞘瘤和脑膜瘤的价值最优[曲线下面积(AUC)0.917;敏感度92%;特异度89%]。结论 MR DWI对桥小脑角区实性神经鞘瘤与脑膜瘤的鉴别诊断有一定的参考价值。     

翼腭窝神经鞘瘤的CT和MRI诊断

目的 分析翼腭窝神经鞘瘤的CT和MRI表现. 资料与方法 回顾性分析12例经组织学证实的翼腭窝神经鞘瘤的影像学资料. 结果 12例神经鞘瘤均为单侧发病,病变以翼腭窝为中心生长并向其通道及周围间隙蔓延,边界清楚,呈卵圆形8例,梭形4例.CT表现:翼腭窝扩大,相应骨质受压变薄、移位及吸收;平扫显示10例病变密度均匀,另2例病变内可见低密度区,5例行CT增强扫描,其中3例病变显示不均匀强化.MRI表现:与脑实质比较,T1WI均呈等信号;T2WI呈等信号9例,高信号3例,10例病灶内可见点、片状高信号,其中5例并可见结节状高信号;增强后不均匀强化,T2WI上所见的高信号区均未见明显强化,其他区域中度或显著强化. 结论 根据典型的骨质及信号改变,可提示本病诊断.     

Imaging of ancient schwannoma

OBJECTIVE: We surveyed the clinical symptoms and radiologic features of ancient schwannoma, a rare variant of schwannoma characterized by degenerative changes. MATERIALS AND METHODS: We present the clinical, radiologic, and pathologic features in seven patients with ancient schwannoma (mean age, 62 years; range, 45-80 years) treated at our department between 1998 and 2003. RESULTS: The most characteristic clinical features were a sign like Tinel's sign and a long interval between the onset of symptoms and surgery (mean interval, 8.3 years). Ancient schwannomas can grow large; the biggest tumor seen in our study was 14 cm long. The highly accurate radiologic assessment made possible with contrast-enhanced MRI and CT scanning showed enhancement at a peridegenerative area and sometimes at a capsule. These findings differ from those of the typical schwannoma and neurofibroma patterns reported to date. Furthermore, bone scintigraphy showed uptake in the tumor, but no accumulation was seen on gallium-67 citrate scintigraphy. CONCLUSION: The characteristic clinical and radiologic findings of ancient schwannoma should make it possible to differentiate it from malignant tumors.     

Displacement of the facial nerve course by vestibular schwannoma: preoperative visualization using diffusion tensor tractography

PURPOSE: To preoperatively visualize the course of the facial nerve, which is displaced by vestibular schwannoma, using diffusion tensor (DT) tractography, and to evaluate the agreement with surgical findings. MATERIALS AND METHODS: The subjects were eight patients with vestibular schwannoma who had undergone removal surgery. DT MR images were obtained and tracts that were considered to represent the facial nerve were constructed. We assessed the success rate for tract construction and evaluated the agreement between tractography findings and surgery. RESULTS: We obtained a tract that connected the internal auditory meatus and brainstem, and was considered to represent the facial nerve in seven of eight cases. The course of the constructed tract agreed with surgical findings in five of these seven cases. One exception was a case in which the tumor was too large to enable intraoperative observation of the facial nerve; however, the facial nerve appeared to be displaced anteriorly at intracapsular resection, in agreement with tractography. In the other case, the schwannoma was mostly cystic. CONCLUSION: Tractographs constructed using MR tensor images enabled us to identify tracts considered to represent facial nerves. We consider DT tractography to be a useful tool for preoperatively predicting facial nerve displacement in vestibular schwannoma.     

Acute brainstem compression by intratumoral hemorrhages in an intracranial hypoglossal schwannoma

A 77-year-old female in the hospital was found tachycardic and hypothermic by a nurse, and the patient’s respiration subsequently ceased. Forensic autopsy revealed an intracranial cystic tumor that would have compressed the brainstem. On microscopic examination, the tumor was diagnosed as an Antoni A schwannoma growth, and recent multiple intratumoral hemorrhages in the intracranial schwannoma were observed, suggesting the sudden enlargement of the intracranial schwannoma due to intratumoral hemorrhaging. Accordingly, we diagnosed the cause of death as brainstem compression induced by the intratumoral hemorrhaging in the intracranial schwannoma. Meanwhile, a rhinopharyngeal tumor was also detected by the autopsy, which was compatible with an antemortem diagnosis of a dumbbell-shaped hypoglossal schwannoma.     

Preoperative detection of the facial nerve by high-field magnetic resonance imaging in patients with vestibular schwannoma

Introduction

Preoperative knowledge of the position of the facial nerve relative to a vestibular schwannoma would be very helpful to decide for an adapted therapeutic strategy. The aim of this study is to assess the feasibility of predicting the course of the facial nerve in vestibular schwannoma patients using 3 T high-resolution magnetic resonance cisternography in a large consecutive series.

Methods

The study was prospectively conducted in 82 patients operated for vestibular schwannoma. All patients underwent preoperative gadolinium (Gd)-enhanced, balanced fast-field echo (bFFE) imaging. The course of the facial nerve was estimated preoperatively and the results were verified with the intraoperative findings.

Results

The facial nerve could be identified by preoperative MRI in 38 cases (46.3 %). In 28 cases (34.1 % of total patients, 73.7 % of identified patients), the course of the MRI-identified facial nerve was completely congruent with the intraoperative findings. In the patient group with MRI-identified facial nerves, tumor size was smaller and the number of solid type was larger. There were 23 cases where the tumor was solid and smaller than 20 mm. Nineteen (82.6 %) of those cases could estimate the facial nerve preoperatively and 16 cases (69.6 %) have complete congruency.

Conclusion

Gd-enhanced bFFE at 3 T is capable of demonstrating the location of the facial nerve in vestibular schwannoma patients prior to surgery. Slices that were perpendicular to the internal auditory canal were useful besides axial images. In small, solid-type tumors, facial nerve was more easily identified than other types of tumors.     

CT of primary hyperaldosteronism (Conn's syndrome): the value of measuring the adrenal gland

OBJECTIVE: The objectives of our study of patients with primary hyperaldosteronism (Conn's syndrome) were to determine whether the adrenal glands are larger in patients with bilateral adrenal hyperplasia than in those with aldosterone-producing adenomas or in healthy control subjects; and whether a CT criterion based on adrenal gland size can be developed to positively diagnose bilateral adrenal hyperplasia. MATERIALS AND METHODS: A retrospective study of CT scans of 28 patients with primary hyperaldosteronism was performed. The means of two observers' measurements of adrenal gland size were recorded and compared with published normal values. In addition, a radiologist experienced in adrenal imaging and unaware of the cause of the primary hyperaldosteronism diagnosed either bilateral adrenal hyperplasia or aldosterone-producing adenoma by visual inspection. RESULTS: The adrenal glands in patients with bilateral adrenal hyperplasia were significantly (p < 0.05) larger than those in patients with aldosterone-producing adenoma or in healthy control subjects. A sensitivity of 100% was achieved when a mean limb width of greater than 3 mm was used to diagnose bilateral adrenal hyperplasia, and a specificity of 100% was achieved when the mean limb width was 5 mm or greater. Receiver operating characteristic curve analysis showed that the overall performance of the radiologist and the mean adrenal limb width in detecting bilateral adrenal hyperplasia were equivalent. CONCLUSION: In patients with primary hyperaldosteronism, adrenal limb measurements on CT can aid in differentiating bilateral adrenal hyperplasia from aldosterone-producing adenoma because the adrenal glands in bilateral adrenal hyperplasia are larger.     

Low-cost high-resolution fast spin-echo MR of acoustic schwannoma: an alternative to enhanced conventional spin-echo MR?

PURPOSETo determine whether unenhanced high-resolution T2-weighted fast spin-echo MR imaging provides an acceptable and less expensive alternative to contrast-enhanced conventional T1-weighted spin-echo MR techniques in the diagnosis of acoustic schwannoma.METHODSWe reviewed in a blinded fashion the records of 25 patients with pathologically documented acoustic schwannoma and of 25 control subjects, all of whom had undergone both enhanced conventional spin-echo MR imaging and unenhanced fast spin-echo MR imaging of the cerebellopontine angle/internal auditory canal region. The patients were imaged with the use of a quadrature head receiver coil for the conventional spin-echo sequences and dual 3-inch phased-array receiver coils for the fast spin-echo sequences.RESULTSThe size of the acoustic schwannomas ranged from 2 to 40 mm in maximum dimension. The mean maximum diameter was 12 mm, and 12 neoplasms were less than 10 mm in diameter. Acoustic schwannoma was correctly diagnosed on 98% of the fast spin-echo images and on 100% of the enhanced conventional spin-echo images. Statistical analysis of the data using the kappa coefficient demonstrated agreement beyond chance between these two imaging techniques for the diagnosis of acoustic schwannoma.CONCLUSIONSThere is no statistically significant difference in the sensitivity and specificity of unenhanced high-resolution fast spin-echo imaging and enhance T1-weighted conventional spin-echo imaging in the detection of acoustic schwannoma. We believe that the unenhanced high-resolution fast spin-echo technique provides a cost-effective method for the diagnosis of acoustic schwannoma.     

脑实质神经鞘瘤影像学表现及相关病理分析

目的：通过对脑实质神经鞘瘤的影像学表现及相关病理分析，提高该病的诊断准确率，有利于手术方案的制定及患者的预后。方法：回顾性分析4例经手术病理及免疫组织化学证实的脑实质神经鞘瘤。其中1例行CT平扫及增强检查，1例行MR平扫，2例行CT及MR平扫＋增强扫描，并结合文献进行分析。结果：4例中，3例年龄小于30岁，均位于幕上；均出现囊变征象，3例出现壁结节，3例增强者中壁结节呈明显强化2例，中度强化1例；1例壁结节内见钙化征象，1例周边水肿明显；病理上均见AntoniA区、B区；免疫组织化学检查，酸性钙结合蛋白（S100）、波形蛋白（Vim）阳性，胶质纤维酸性蛋白（GFAP）、上皮膜抗原（EMA）阴性。结论：脑实质神经鞘瘤好发于青少年，囊变及周围水肿为其特征性表现，结合病理及免疫组织化学检查有利于最终确诊。     

Focal T2 hyperintensity in the dorsal brain stem in patients with vestibular schwannoma

BACKGROUND AND PURPOSE: The vestibular nucleus cannot be visualized on MR imaging, but some patients with vestibular schwannoma show a tiny area of hyperintensity in the dorsal brain stem on T2-weighted images. The aim of this study was to determine whether this tiny area is characteristic of vestibular schwannoma. METHODS: We retrospectively reviewed the postoperative MR images of 53 patients with cerebellopontine angle tumor. MR images were obtained with a 1.5T scanner. Spin-echo pre- and postcontrast 3-mm-thick T1-weighted axial images, 3-mm-thick fast spin-echo (FSE) T2-weighted axial images, and 0.8-mm-thick constructive interference in steady state (CISS) axial images were acquired. Surgical and histopathologic diagnosis was vestibular schwannoma (41/53 = 77%), meningioma (7/53 = 13%), epidermoid cyst (3/53 = 6%), glioma with exophytic growth (1/53 = 2%), and chordoma (1/53 = 2%). RESULTS: A tiny area of hyperintensity was observed at the lateral angle of the fourth ventricle floor in 6 patients (3 men, 3 women; age range, 24-54 years; mean age, 43 years) with vestibular schwannoma larger than 2 cm in maximal diameter on both FSE T2-weighted and CISS images. Preoperative MR images with the same pulse sequences showed the same area of hyperintensity in all these patients. CONCLUSION: Because the location of the area of hyperintensity is coincident with the vestibular nucleus, the hyperintensity may represent degeneration of the nucleus. This hyperintensity should not be confused with a postoperative lesion or a small infarction. If such hyperintensity is seen in a patient with a large cerebellopontine angle tumor, a diagnosis of vestibular schwannoma is suggested.     

肾上腺皮质功能减退时垂体-肾上腺皮质激素的改变

为评估血浆ACTH、血清皮质醇、尿游离皮质醇(UFC)水平及垂体和肾上腺皮质储备功能试验对原发性和继发性肾上腺皮质功能减退症的诊断和鉴别诊断价值，回顾性分析了16例已确诊为Addison病和75例垂体或下丘脑功能减退患者的血浆ACTH、血清皮质醇和UFC水平的改变，以及ACTH刺激试验、胰岛素低血糖刺激试验和氨基导眠能试验的特点。结果显示，原发性肾上腺皮质功能减退病人血浆ACTH水平普遍显著升高，血清皮质醇和UFC绝大多数患者降低，但少数病人正常，且对ACTH刺激试验无反应。继发性肾上腺皮质功能减退患者多数人血浆ACTH正常，而血清皮质醇和(或)UFC降低，他们对胰岛素低血糖试验或氨基导眠能试验无反应，对ACTH刺激试验呈延迟或正常反应。结果表明，皮质醇和UFC水平降低是绝大多数肾上腺皮质功能减退症病人的特征。ACTH水平是鉴别原发性或继发性肾上腺皮质功能减退的关键，原发性者ACTH水平升高，继发性者ACTH水平不高。ACTH刺激试验是诊断原发性肾上腺皮质功能减退症的有用工具，胰岛素低血糖试验和氨基导眠能试验是诊断继发性肾上腺皮质功能减退症的可靠依据。     

Use of CT in metastatic adrenal gland tumor

The autopsy findings and CT scans on patients with adrenal metastatic tumor over a six year period were analyzed. No pattern on CT was felt to be specific for metastatic tumor to the adrenal glands. Bilateral adrenal metastatic disease was found more common than unilateral disease by CT and by autopsy. All patients with adrenal metastatic disease had metastatic disease elsewhere. CT showed the other metastatic disease in approximately 90% of the cases. All our patients with follow-up scans showed change in the size of the tumor. CT remains the modality of choice for evaluation of the adrenal glands.     

血浆ACTH、血清皮质醇测定对肾上腺皮质功能减退的诊断价值

本文报告原发肾上腺皮质功能减退(PAF)患者13例、继发肾上腺皮质功能减退(SAF)患者31例及正常人42名血浆ACTH及血清皮质醇测定的结果。血浆ACTH:PAF组显著高于正常组;SAF组显著低于正常组;PAF组与SAF组或正常组无重叠,但SAF组与正常组有较多重叠(83.9％)。血清皮质醇:PAF组、SAF组均显著低于正常组;PAF和SAF两组相似,但与正常组有少量重叠(13.6％),其中14例SAF、3例PAF和13名正常人做了氨基导眠能试验。SAF和正常人两组服药后血浆ACTH的重叠现象消失。本文结果表明,血清皮质醇是诊断肾上腺皮质功能减退的直接证据。但不能鉴别PAF和SAF,而血浆ACTH可以鉴别两者,氨基导眠能试验有助于鉴别SAF和正常人。     

Predictive value of benign percutaneous adrenal biopsies in oncology patients

PURPOSE: Percutaneous CT guided biopsy is accepted as a safe procedure for the diagnosis of indeterminate adrenal masses in oncologic patients. The purpose of this study was to evaluate the accuracy of a 'negative for tumour' adrenal biopsy in the oncologic patient population by assessing subsequent outcome including clinical course, size and imaging characteristics of the adrenal lesions on follow-up imaging studies and pathological findings at re-biopsy or following adrenal mass resection. MATERIALS AND METHODS: Retrospective analysis of 225 oncological patients (FM, 128;87; age range 33-87 years, mean age 66 years) who had undergone CT guided biopsies of an adrenal mass over a 5-year period was performed. Those patients with a report consistent with 'negative for malignancy' were evaluated by reviewing the medical records for patient demographics, primary malignancy, histology of adrenal tumour, subsequent surgical interventions, repeat adrenal biopsy under image guidance, by open surgery or at autopsy, subsequent abdominal imaging in which the adrenal gland was imaged, and long-term outcome including hospital admissions, or death. RESULTS: Of the 225 CT-guided adrenal biopsies performed, 41 (18%) were negative for neoplasm. The primary neoplasm in these 41 patients included lung cancer (n=32), breast (n=5), renal cell carcinoma (n=2), bladder (n=1), and prostate (n=1). The size of the adrenal lesions ranged from 2.8-5 cm. Of the 41 biopsies, which were negative for tumour; 10 were identified as adenomas and the rest showed benign adrenal cortical cells or hyperplasia on cytopathology and histopathology. Repeat biopsies were obtained in 13/41 (31%) patients; whereas 2/41 (5%) had their adrenal gland analyzed on post mortem examination. None of these 15 repeat evaluations yielded tumour. CONCLUSION: In oncological patients, pathological analysis of tissue samples obtained by CT-guided percutaneous biopsy, suggesting benign aetiology, is reliable and predicts a benign course on long-term follow-up. A negative or benign pathology result for a CT guided percutaneous adrenal biopsy can be regarded as a true negative evaluation in oncological patients with no necessity to repeat the biopsy.     

马尾神经鞘瘤的临床特点与外科治疗

目的探讨马尾神经鞘瘤的临床特点与外科手术治疗方法。方法回顾性分析2007年6月-2009年3月经手术治疗的32例马尾神经鞘瘤患者的临床症状、影像学改变和外科手术治疗效果。结果多数患者术前出现下肢疼痛麻木的症状(30例),其中18例为双下肢疼痛麻木,体检时25例表现为双侧神经损害或单侧多根神经损害。12例患者首发症状为单纯腰痛。10例误诊为腰椎间盘突出症。6例行CT扫描,但均未能做出正确诊断。所有患者均经MRI确诊,神经鞘瘤表现为圆形或椭圆形病灶,T1加权像呈等或稍低于脊髓信号,T2加权像25例呈不均匀高信号,2例呈稍高信号,5例呈均匀高信号。13例行钆增强扫描,10例呈不均匀强化或环形强化。所有患者均完整切除肿瘤,除1例巨大马尾神经鞘瘤术后症状加重外,其他患者术后功能均改善,短期随访未见复发。结论马尾神经鞘瘤的特征性表现为双下肢疼痛麻木;查体显示双侧或单侧多根神经损伤,但首发症状可不典型;MRI有助于早期诊断;外科手术完整切除肿瘤效果良好。