The somatotopic localisation of the descending cortical tract in the cerebral peduncle: a study using MRI of changes following Wallerian degeneration in the cerebral peduncle after a supratentorial vascular lesion

We studied the effects of Wallerian degeneration in the cerebral peduncle shown by magnetic resonance imaging (MRI) following a supratentorial vascular lesion, to identify the somatotopic localisation of the descending cortical tracts. Patients with a lesion involving a large area of a cerebral hemisphere had an area of abnormal signal intensity in the whole cerebral peduncle, suggesting Wallerian degeneration of all the whole descending cortical tracts. With a small lesion confined to the precentral gyrus, corona radiata, or posterior limb of the internal capsule there was an abnormal signal at the centre of the peduncle, suggesting degeneration of the precentrospinal tract. Those with a small lesion confined to the paracentral gyrus had an abnormal area slightly lateral to the centre of the peduncle, suggesting degeneration of the parietospinal tract. Patients with a lesion of the parietal or temporal lobes, not including the paracentral or precentral gyri, corona radiata, or the posterior limb of the internal capsule, had an abnormal area laterally in the peduncle, suggesting degeneration of the parietopontine or temporopontine tract.     

Clinical correlates of high signal lesions on magnetic resonance imaging in Alzheimer's disease

Summary The pathophysiology and clinical significance of high signal lesions, visualized on magnetic resonance imaging (MRI) in patients with Alzheimer's disease (AD), remain controversial. Since they are known to correlate with vascular disease and vascular risk factors, we reviewed the clinical correlates of periventricular high signal (PVH) and subcortical white matter lesions (WML) in a sample of 106 patients with probable AD, excluding persons with treated vascular risk factors or symptomatic cerebrovascular and cardiovascular disease. Grade 2 PVH were seen in 26 (25%) and scattered WML were identified in 29 (18%). PHV were associated with advancing age and gait disturbance. WML were associated with gait disturbance and incontinence. Neither radiologic finding was related to dementia severity. The findings suggest that these lesions are common in patients with AD even when those with evidence of cerebrovascular disease are excluded; their presence, therefore, should not preclude a diagnosis of AD. Additionally, the data suggest that HSL on MRI may be one of many risk factors associated with functional disability in persons with probable AD.     

A new operational approach for the piriform sinus fistula

It has been well documented that piriform sinus fistulae often cause suppurative thyroditis; however, when a piriform sinus fistula does not present this symptom, making a correct diagnosis is very difficult. We have experienced 11 cases of a piriform sinus fistula. The conventional operational approach was performed in the initial eight patients, among which there were four recurrences in two patients. Therefore, a new operational approach was introduced for the three most recent cases and one recurrent case. First, the existence of the internal orifice of the fistula is confirmed with a laryngoscope, after which a transverse incision on the neck is made and the abscess dissected. The side wall of the piriform sinus is then opened with the help of a laryngoscope and the bottom part of the mucosa of the sinus transected with the internal orifice of the fistula, after which the fistula is removed en bloc with the bottom part of the sinus and abscess cavity. Using this operation, we experienced no complications and there has been no recurrence so far.This paper was presented at the 23rd Annual Meeting of Pacific Association of Pediatric Surgeons, June 1990 in Kona, Hawaii.     

肝VX-2 瘤模型MR扩散成像的实验研究

目的探讨肝VX-2瘤模型MR扩散成像特征.方法新西兰大白兔35只,采用块种植的方法,一期预实验皮下种植14只,肝内种植6只;二期肝内种植12只,另3只做正常对照.对包括二期肝内种植在内的15个肿瘤于种植前后行定期扩散加权成像(DWI) 与MR检查.以表观扩散系数(ADC)值等为指标进行统计分析.结果 (1)一期预实验,皮下种植成功率29%(4/14),肝内种植成功率33%(2/6);二期肝内种植成功率83%(10/12).(2)VX-2瘤在DWI上呈高信号,边缘清楚.正常组与VX-2瘤实验组b值为100和300 s/mm2时ADC值分别为(2.57±0.26)mm2/s、(1.73±0.31)mm2/s、(1.87±0.25)mm2/s与(1.57±0.23)mm2/s(F=43.26,P<0.001).随b值增大,病灶信号降低;ADC图上病灶呈低信号;不同b值之间病灶ADC值差异有统计学意义(P<0.05);b=100 s/mm2病灶与正常肝脏之间ADC值差异有统计学意义(P<0.01).(3)VX-2瘤发展迅速,易发生肺、肝、纵隔等处转移.结论 DWI在反映肝VX-2瘤内部水分子运动、发现与追踪病灶进展等方面有重要价值.     

乳腺占位病变的高场强MRI诊断价值

目的 :总结乳腺良恶性占位病变在高场强MRI的影像表现 ,评价高场强MRI对乳腺良恶性病变的诊断价值。方法 :搜集1996～ 2 0 0 4年间经手术病理证实的 4 3例乳腺良恶性占位病变的MRI资料 ,分析其影像表现。结果 :典型乳腺良、恶性病变 ,高场强MR平扫即能准确诊断 ,而部分非典型良、恶性病灶 ,增强扫描形态、信号变化也有一定的重叠。结论 :MRI技术能够充分显示病变形态及与周围组织结构之间的关系 ,是建议活检或预防性手术的最有力的依据。但是 ,MRI平扫、增强技术对乳腺非典型病变 ,仍然有局限性     

MRI同层动态增强对垂体微腺瘤的诊断价值

目的：分析垂体微腺瘤的MPd同层动态增强特征。方法：对40例临床怀疑为垂体微腺瘤的病人行同层动态增强MPd扫描，并绘出时间一信号强度曲线图。结果：40例病人中共检出垂体微腺瘤26例。同层动态增强后垂体微腺瘤的MPd表现为圆或椭圆形的低或稍低信号，似“充盈缺损”；垂体微腺瘤的最大信号强度多出现在注入造影剂后32～96s，以64s最明显。结论：同层MPd动态增强对垂体微腺瘤的诊断有较高价值。     

A binocular machine vision system for three-dimensional surface measurement of small objects

Rendering three-dimensional information of a scene from optical measurements is very important for a wide variety of applications. However, computer vision advancements have not yet achieved the accurate three-dimensional reconstruction of objects smaller than 1 cm diameter. This paper describes the development of a novel volumetric method for small objects, using a binocular machine vision system. The achieved precision is high, providing a standard deviation of 0.04 mm. The robustness, of the system, issues from the lab prototype imaging system with the crucial z-axis movement without the need of further calibration and the fully automated volumetric algorithms.     

原发性胸椎原始神经外胚层肿瘤的动态增强MRI表现

目的 初步探讨原始神经外胚层肿瘤(PNET)的动态增强MRI表现，以及对其诊断及鉴别诊断的价值。方法 用动态增强MRI方法对已手术和病理证实的2例胸椎PNET行3次MR检查并进行前瞻性研究。结果 在信号强度-时间和对比增强率．时间曲线上，2例PNET3次检查均表现为快升慢降型，即肿瘤早期就开始迅速增强，上升峰极陡，60～120s即达到高峰水平，然后保持平坦，3．5min内未见明显下降曲线。结论 动态增强MRI扫描能帮助对PNET进行早期诊断和鉴别诊断，从而为临床选择治疗方案及估计预后提供较为可靠的依据。     

超声心动图对主动脉窦瘤破裂合并畸形的诊断价值

目的 评价超声心动图对主动脉窦瘤破裂合并畸形的诊断价值，探讨漏诊原因，以提高诊断阳性率。方法 回顾分析23例主动脉窦瘤破裂合并畸形的超声心动图特征，比较超声心动图与手术诊断结果。结果 超声心动图对主动脉窦瘤破裂合并畸形诊断符合率为86．95％（20／23），漏诊率为13．04％（3／23）。结论 超声心动图检查对诊断主动脉窦瘤破裂合并畸形有重要的临床价值，全面掌握超声知识，仔细认真地检查可避免漏诊。