四脑室顶位置磁共振成像的临床定量研究

目的：用ＭＲＩ测量正常国人各性别、年龄组及Ｃｈｉａｒｉ畸形患者的第四脑室顶高距与水平距,以探讨其正常值范围及四脑室顶位置的发育规律。材料与方法：在颅脑（旁）正中矢状面ＳＥＴ１ＷＩ上测量３１７例正常国人和４２例Ｃｈｉａｒｉ畸形及可疑病人的第四脑室顶高距及水平距。正常组按性别、年龄分为１６组,每组２０例（７０岁以上女性组１７例）。ＭＲＩ应用１．０Ｔ全身ＭＲ机,用ｔ检验作统计分析。结果：四脑室顶高距女性为３０．０ｍｍ±１．９ｍｍ,男性为２９．６ｍｍ±２．９ｍｍ～３２．２ｍｍ±３．５ｍｍ;仅部分男性有显著年龄差异,但无显著性别差异。四脑室顶水平距男性为１１．０ｍｍ±１．５ｍｍ,女性为１０．６ｍｍ±１．３ｍｍ,无显著性别、年龄差异。Ｃｈｉａｒｉ畸形的四脑室高距明显低于正常人（Ｐ＜０．０１）,可疑组也明显低于部分年龄组正常男性（Ｐ＜０．０５）,而其水平距与正常各性别、年龄组的无显著差异（Ｐ＞０．０５）。结论：第四脑室顶位置有一定的生长发育规律,Ｃｈｉａｒｉ畸形常伴四脑室顶下移。     

早期帕金森病123I-β-CIT脑SPECT显像研究

目的研究早期帕金森患者纹状体中多巴胺转运体的丢失情况。方法通过７例单侧帕金森患者及７例年龄、性别匹配（年龄±５年）的正常人１２３Ｉ２βｃａｒｂｏｍｅｔｈｏｘｙ３β（４ｉｏｄｏｐｈｅｎｙｌ）ｔｒｏｐａｎｅ（βＣＩＴ）脑ＳＰＥＣＴ显像，计算纹状体与小脑的放射性比值及纹状体中１２３ＩβＣＩＴ摄取的非对称指数，分析患者症状侧及症状对侧纹状体特异性１２３ＩβＣＩＴ的摄取。结果纹状体３小时及１８小时特异性摄取１２３ＩβＣＩＴ正常人为３０±０５和５５±０６；患者症状对侧为２０±０８和３１±０４，症状侧为２３±０４和４０±０５。与正常人比较，患者双侧纹状体的１２３ＩβＣＩＴ特异性摄取明显下降（Ｐ＜００１），症状侧纹状体摄取下降与年龄有关（Ｐ＜００５），症状对侧纹状体摄取下降与年龄无关（Ｐ＞００５）。结论早期帕金森患者双侧纹状体多巴胺转运体有不同程度的丢失，症状对侧丢失更明显     

四脑室机位置磁共振成像的临床定量研究

目的：用ＭＲＩ测量正常国人各性别、年龄组及Ｃｈｉａｒｉ畸形患者的第四脑室顶高距与水平距,以探讨其正常值范围及四脑室顶位置的发育规律。材料与方法：在颅脑（旁）正 矢状在ＳＥＴ１ＷＩ上测量３１７例正常国人和４２例Ｃｈｉａｒｉ畸形及可疑病人的第四脑室顶高距及水平距。正常组按性别、年龄分为１６组,每组２０例,ＭＲＩ应用１．０Ｔ全身ＭＲ机,用ｔ检验作统计分析。结果：四脑室顶高距女性为３０．０ｍｍ±１．９ｍｍ     

MRI在Arnold－ChiariⅠ型畸形诊断中的应用（附50例分析）

笔者对ＭＲＩ证实的５０例Ａｒｎｏｌｄ－ＣｈｉａｒｉＩ型畸形（ＡＣＭ－Ｉ）进行分析。依小脑扁桃体下疝程度不同分为１～１０ｍｍ（３０例）和１１～２３ｍｍ（２０例）两组。另有５０例ＭＲＩ证实为非Ｃｈｉａｒｉ畸形者为对照组。全部测定枕大孔前后径。结果表明，ＡＣＭ－Ｉ枕大孔前后径增大和脊髓空洞症发生率均与小脑扁桃体下疝程度成正相关。文内对Ｃｈｉａｒｉ畸形的病因和发病机制以及ＡＣＭ－Ｉ诊断标准等进行了讨论。     

超声心动图在二尖瓣球囊成形中的应用价值

目的：应用超声心动图检查方法估价二尖瓣球囊成形术的疗效。材料和方法：选择１９９１０１～１９９５０４，２５例风湿性二尖瓣狭窄拟行二尖瓣球囊扩张患者于术前４８小时，术后立即及５～７天，部分患者于术后３个月，６个月及１年进行超声心动图随访观察。结果：二尖瓣球囊扩张后检查二尖瓣口面积由术前０８５±０２０ｃｍ扩大至１６９±０３０ｃｍ；瓣下最大血流速度（Ｖｍａｘ）由（２３５±０３９）ｍ／ｓ降至（１６０±０３３）ｍ／ｓ；ＰＧｍａｘ及ＰＧｍｅａｎ分别由术前（２９±１０）ｋＰａ及（１８±０８）ｋＰａ降至（１４±０５）ｋＰａ及（０６±０３）ｋＰａ。本组术后房间隔穿刺部位缺口以４～６ｍｍ多见，２３例（９２％）出现房水平左向右分流，２例１年检查仍存在分流。术后再狭窄最早出现时间为３个月３例（３／１７），６个月１例（１／１１）。结论：本组２５例二尖瓣球囊成形患者均获得成功，其效果满意。超声心动图可用于评价二尖瓣球囊成形术的效果并可及时检出其并发症。     

44例Arnold－Chiari Ⅰ型畸形的MRI分析

目的：分析ＭＲＩ对Ａｒｎｏｌｄ－Ｃｈｉａｒｉ畸形的诊断价值及枕大孔前后径、小脑扁桃体垂直径同该病的关系。材料与方法：回顾性分析４４例ＣｈｉａｒｉⅠ型畸形的ＭＲＩ表现。选择４４例经ＭＲＩ证实的正常病例作为对照组，测量所有病例的枕大孔前后径及小脑扁桃体垂直径，采用ｔ检验进行统计学分析。结果：本组中８２％（３６／４４）有不同程度的脊髓空洞症，７７％（３４／４４）有延髓的拉长疝出，２５％（１１／４４）合并骨质发育异常。两组之间枕大孔前后径无显著性差异（Ｐ＞０．０５），小脑扁桃体垂直径有高度显著性差异（Ｐ＜０．００１）。结论：ＭＲＩ是Ａｒｎｏｌｄ－Ｃｈｉａｒｉ畸形及其合并症的最佳诊断方法，小脑扁桃体垂直径增大对诊断有重要价值。     

儿童正常垂体腺的MR研究

目的：通过ＭＲＩ研究儿童正常垂体腺形态、大小及信号强度。材料和方法：５２例非垂体腺疾病的颅脑ＭＢ资料。年龄３～１５岁。观察测量矢状面Ｔ１加权图像上垂体腺的形态、高径、垂体柄宽径及后叶信号特征。结果：儿童正常垂体腺形态分：平坦型２７例（５１．９％），凹陷型１５例（２８．８％），隆凸型１０例（１９．３％）。垂体腺高径：３～５岁３．９±０．３ｍｍ，５．１～１０岁４．２±０．５ｍｍ，１０．１～１５岁５．３±０．４ｍｍ。垂体柄宽径１．４±０．５ｍｍ。垂体后叶均呈高信号（１００％）。结论：１．儿童垂体腺形态以平坦型最常见。２．垂体腺高径与年龄呈正线性关系。３．垂体柄未见中断。     

~(99m)Tc-ECD SPECT断层影像采血法和非采血法定量测定rCBF和CBF的对照研究

目的：应用９９ｍＴｃＥＣＤＳＰＥＣＴ断层影像采血和非采血法定量测定ｒＣＢＦ和ＣＢＦ。材料和方法：正常对照组１５例,疾病组１０例。采血法用动脉化静脉血样求得血中９９ｍＴｃＥＣＤ的浓度;非采血法用头颈平面像求得血中９９ｍＴｃＥＣＤ浓度。结果：正常对照组采血法ｒＣＢＦ２５０±４０～５９１±７６ｍｌ．ｍｉｎ－１·（１００ｇ）－１,ＣＢＦ４３０±３６ｍｌ．ｍｉｎ－１·（１００ｇ）－１;非采血法ｒＣＢＦ２６１±３２～６０３±６８ｍｌ．ｍｉｎ－１·（１００ｇ）－１,ＣＢＦ４３５±４４ｍｌ．ｍｉｎ－１·（１００ｇ）－１。和其他方法测得的正常值很接近。疾病组两法测定的结果基本一致。结论：用９９ｍＴｃ－ＥＣＤＳＰＥＣＴ断层影像测定ｒＣＢＦ和ＣＢＦ是可行的,可作为评价脑血流灌注的定量指标。     

CO2激光治疗传染性软疣48例

资料：４８例中男１３例,女３５例;年龄３～５６岁。病程１～６个月。每例皮损数３～４５８个。方法：ＣＯ２激光波长１０６μｍ,输出功率１５Ｗ,光斑直径０２ｍｍ,照射时间１５～２ｓ,距２ｃｍ处激光聚焦头对准皮损中心汽化,术后创面无需任何处理。结果：４...     

CO_2激光系带成形术的临床体会

利用ＣＯ２激光行上唇系带成形术３８例,舌系带成形术２１例。ＣＯ２激光机的波长１０６μｍ,输出功率４～５Ｗ,连续波输出,光斑直径＜０５ｍｍ。手术时将系带拉至最大张力。以波长为６５５ｎｍ的半导体激光引导定位。距系带５～６ｍｍ处作者单位：大连市口腔医院...     

斜坡的磁共振成像测量研究

目的　用MRI测量正常国人和Chiari畸形患者的斜坡长度和倾斜角 ,以探讨其正常值范围及其发育规律。材料与方法　在颅脑正中矢状面SET1WI上测量了 3 17例正常人、2 9例Chiari畸形和 13例可疑患者的斜坡长度和倾斜角。正常人按性别和年龄分为 16组 ,每组 2 0例 ( 70岁以上女性组仅 17例 )。MRI应用 1.0T超导MR系统 ,并以t检验作统计分析。结果　正常斜坡长度和倾斜角随性别、年龄不同而有所差异。男性斜坡长于女性 (P <0 .0 5 ) ,且于 2 0岁前随年龄而增长 ,之后基本稳定 ;其倾斜角于 2 0岁前随年龄而增大 ,于 3 0岁前后基本稳定 ,两性差异无显著性 (P >0 .0 5 )。Chiari畸形及可疑患者斜坡长度短于正常人 (P <0 .0 5 ) ,其倾斜角也小于正常人 (P <0 .0 5 )。结论　斜坡长度和倾斜角有一定的正常范围和发育规律 ;斜坡短于 41mm为发育过短 ,倾斜角小于 5 0°为斜坡发育过平。Chiari畸形以小脑扁桃体下端位置低于颅基线 3mm作为诊断标准为宜 ,其常伴斜坡短平。     

Chiari III malformation: imaging features.

PURPOSE: To analyze and discuss the MR and CT features of Chiari type III malformations. PATIENTS AND METHOD: MR and CT studies in nine neonates born at term with Chiari type III malformations were retrospectively reviewed. RESULTS: High cervical/low occipital encephaloceles were present in all cases. Hypoplasia of the low and midline aspects of the parietal bones was seen in four patients. The encephaloceles contained varying amounts of brain (cerebellum and occipital lobes, six cases; cerebellum only, three cases), ventricles (fourth, six cases; lateral, three cases), cisterns, and in one case, the medulla and pons. Associated anomalies included: petrous and clivus scalloping (five cases/nine cases), cerebellar hemisphere overgrowth (two cases/nine cases), cerebellar tonsillar herniation (three cases/seven cases), deformed midbrain (nine cases), hydrocephalus (two cases/nine cases), dysgenesis of the corpus callosum (six cases/nine cases), posterior cervical vertebral agenesis (three cases/eight cases), and spinal cord syrinxes (two cases/seven cases). In four patients who underwent surgical resection and closure, aberrant deep draining veins and ectopic venous sinuses within the encephaloceles were found. Pathology examination of the encephalocele (four cases/nine cases) showed multiple anomalies (necrosis, gliosis, heterotopias, meningeal fibrosis) that were not demonstrable by either MR or CT. The marked disorganization of the tissues contained within the cephalocele may account for the lack of MR sensitivity to these abnormalities. CONCLUSION: Preoperative determination of the position of the medulla and pons is essential and is easily accomplished by MR. To avoid surgical complications, the high incidence of venous anomalies should be kept in mind.     

Significance of cerebellar tonsillar position on MR

It has been noted that a low degree of ectopia of the cerebellar tonsils on MR is of questionable significance. We measured the position of the cerebellar tonsils with respect to the inferior aspect of the foramen magnum in 200 normal patients and in 25 patients with a firm diagnosis of Chiari I malformation. In the normal group, the mean position of the tonsils was 1 mm above the foramen magnum with a range from 8 mm above the foramen magnum to 5 mm below. In the patients with Chiari I malformations, the mean position was 13 mm below the foramen magnum with a range from 3 mm below the foramen magnum to 29 mm below. Fourteen percent of normal patients had tonsils extending slightly below the foramen magnum. If 2 mm below the foramen magnum is taken as the lowest extent for tonsils in a normal patient, our sensitivity in predicting symptomatic patients is 100% and our specificity is 98.5% (three false positives). If 3 mm below the foramen magnum is taken as the lowest normal tonsillar position, our sensitivity is 96% and our specificity is 99.5%. MR demonstration of less than 2 mm of tonsillar ectopia is probably of no clinical significance in the absence of syringomyelia.     

Chiari I malformations: clinical and radiologic reappraisal.

Clinical findings and magnetic resonance (MR) images in 68 patients with Chiari I malformations were retrospectively analyzed to identify those radiologic features that correlated best with clinical symptoms. A statistically significant (P = .03) female predominance of the malformation was observed, with a female: male ratio of approximately 3:2. Associated skeletal anomalies were seen in 24% of patients. Syringomyelia was detected in 40% of patients, most commonly between the C-4 and C-6 levels. Of the 25 patients who presented with spinal symptoms, 23 (92%) proved to have a syrinx at MR imaging. When the syrinx extended into the medulla (n = 3), however, brain stem symptoms predominated. Patients with objective brain stem or cerebellar signs had the largest mean tonsillar herniations. Patients with tonsillar herniations greater than 12 mm were invariably symptomatic, but approximately 30% of patients with tonsils herniating 5-10 mm below the foramen magnum were asymptomatic at MR imaging. "Incidental" Chiari I malformations are thus much more common than previously recognized, and careful clinical assessment remains the cornerstone for proper diagnosis and management.     

Spinal intradural cerebellar ectopia.

An ectopic cerebellum, as in Chiari malformations and ectopic cerebellar dysplastic tissue, is a common finding; however, the presence of an organized ectopic cerebellum is exceedingly rare. We describe the MR imaging, surgical, and histologic appearance of an intraspinal ectopic cerebellum in an infant.     

Study of automated segmentation of the cerebellum and brainstem on brain MR images

MR imaging is an important method for diagnosing abnormalities of the brain. This paper presents an automated method to segment the cerebellum and brainstem for brain MR images. MR images were obtained from 10 normal subjects (male 4, female 6; 22-75 years old, average 31.0 years) and 15 patients with brain atrophy (male 3, female 12; 62-85 years of age, average 76.0 years). The automated method consisted of the following four steps: (1) segmentation of the brain on original images, (2) detection of an upper plane of the cerebellum using the Hough transform, (3) correction of the plane using three-dimensional (3D) information, and (4) segmentation of the cerebellum and brainstem using the plane. The results indicated that the regions obtained by the automated method were visually similar to those obtained by a manual method. The average rates of coincidence between the automated method and manual method were 83.0+/-9.0% in normal subjects and 86.4+/-3.6% in patients.     

Diffusion-weighted and conventional MR imaging findings of neuroaxonal dystrophy

BACKGROUND AND PURPOSE: Neuroaxonal dystrophy is a rare progressive disorder of childhood characterized by mental deterioration and seizures. The diffusion-weighted and conventional MR imaging findings are reported for six cases. METHODS: Six patients aged 19 months to 9 years with proved neuroaxonal dystrophy (one with the infantile form, five juvenile forms) underwent imaging at 1.5 T. Echo-planar diffusion-weighted images were acquired with a trace imaging sequence in five patients and with a three-gradient protocol (4000/110) in one. Images obtained with a b value of 1000 s/mm2 and corresponding apparent diffusion coefficient (ADC) maps were studied. ADCs from lesion sites and normal regions (pons and temporal and occipital lobes) were evaluated. RESULTS: A hyperintense cerebellum (a characteristic of the disease) was evident on fluid-attenuated inversion recovery images in all cases. Four patients had associated cerebral changes. Diffusion-weighted images, especially ADC maps, showed an elevated diffusion pattern in the cerebellum in the five juvenile cases (normal images at b = 1000 s/mm2, ADCs of 1.30-2.60 x 10(-3) mm2/s). A restricted diffusion pattern was evident in the infantile case (hyperintensity at b = 1000 s/mm2, low ADCs of 0.44-0.55 x 10(-3) mm2/s). ADCs were normal in the pons and temporal and occipital lobes (0.64-1.00 x 10(-3) mm2/s). CONCLUSION: An elevated cerebellar diffusion pattern is a predominant feature of juvenile neuroaxonal dystrophy. Coexistent elevated and restricted diffusion patterns were evident in different brain regions in different forms of the disease. Dystrophic axons likely account the restricted diffusion, whereas spheroid formation (swelling) and abnormal myelination result in elevated diffusion.     

Position of cerebellar tonsils in the normal population and in patients with Chiari malformation: a quantitative approach with MR imaging

Magnetic resonance imaging was used to define quantitatively the position of the cerebellar tonsils in the normal population and in patients with Chiari malformations. The average distance of the tonsillar tips from the foramen magnum was 2.9 +/- 3.4 mm above the foramen in 82 subjects without posterior fossa abnormality or increased intracranial pressure, and 10.3 +/- 4.6 mm below the foramen in 13 patients with Chiari malformations (p less than 0.005). Consequently, extension of the tonsils below the foramen magnum is considered normal up to 3 mm, borderline between 3 and 5 mm, and clearly pathologic when it exceeds 5 mm.     

Chiari type III malformation: Case report and review of literature

Chiari III (CM III) is the rarest of the Chiari malformations, characterized by high cervical or occipital encephalocele and osseous defects, associated with herniation of the posterior cerebral fossa contents through the foramen magnum.We report the case of a female newborn, with a cervico-occipital mass, hypotonia and sharp osteotendinous reflexes in the lower limbs. An MRI was performed showing a low occipital encephalocele with caudal displacement of cerebellar tonsils.Because of its high contrast resolution, MRI is more useful than CT, preoperatively, to assess the content of the encephalocele. MRI can identify the position of the brain stem and spinal cord, so that they are preserved during the surgical procedure.