钡灌肠和CT及MRI对结直肠癌诊断的比较影像学研究

目的比较钡灌肠(BE)、计算机X线断层扫描(CT)和磁共振成像(MRI)对结直肠癌检查的临床价值。方法对64例经临床拟诊结直肠癌患者的影像学资料进行对比分析。结果64例患者中39例行BE检查,31例行螺旋CT检查,42例行MRI检查。其中经手术病理证实的结直肠癌54例。BE、CT和MRI对结直肠癌检查的敏感度分别为96.9%、96.2%和97.1%;准确度分别为92.3%、83.9%和90.5%。CT和MRI对结直肠癌T分期诊断的准确度分别为73.1%和82.9%。结论BE是结直肠癌的基本影像学检查方法,CT和MRI是BE必要的补充检查手段,BE加MRI是诊断结直肠癌的优选组合检查方法。     

Automatic algorithm for correcting motion artifacts in time-resolved two-dimensional magnetic resonance angiography using convex projections.

Time-resolved contrast enhanced magnetic resonance angiography (MRA) may suffer from involuntary patient motion. It is noted that while MR signal change associated with motion is large in magnitude and has smooth phase variation in k-phase, signal change associated with vascular enhancement is small in magnitude and has rapid phase variation in k-space. Based upon this observation, a novel projection onto convex sets (POCS) algorithm is developed as an automatic iterative method to remove motion artifacts. The presented POCS algorithm consists of high-pass phase filtering and convex projections in both k-space and image space. Without input of detailed motion knowledge, motion effects are filtered out, while vasculature information is preserved. The proposed method can be effective for a large class of nonrigid motions, including through-plane motion. The algorithm is stable and converges quickly, usually within five iterations. A double-blind evaluation on a set of clinical MRA cases shows that a completely unsupervised version of the algorithm produces significantly better rank scores (P=0.038) when compared to angiograms produced manually by an experienced radiologist.     

MRI在心脏瓣膜病中的诊断价值

目的 探讨多序列MR扫描在心脏瓣膜病中的诊断价值。方法 回顾性分析56例心脏瓣膜病患者的影像学资料，患者分别采用超声心动图（UCG）、二维（2D）黑血及亮血序列、K-空间节段真实稳态进动快速扫描序列（True FISP）对瓣膜病进行定性评价，15例患者还进行小角度快速激发（FLASH）电影序列和流速编码电影（VEC）定量分析，并将MR结果与UCG进行对比。结果 UCG和MRI诊断二尖瓣狭窄（MS）2例，二尖瓣关闭不全（MI）23例；主动脉瓣狭窄（AS）7例，其中二瓣畸形5例；主动脉瓣关闭不全（AI）13例；三尖瓣关闭不全（TI）2例；复合或联合瓣膜病9例。受累心腔的增大和升主动脉的扩张是其主要形态学改变，异常的血液湍流信号是受累瓣膜的直接征象。VEC-MR定量分析与多普勒超声一致性好：6例AS，MR和UCG检查结果相关性分析，相关系数和校正相关系数分别为：R=0，975、Rsq=0．951（P〈0．01），AI9例，分别为R=0．965、Rsq=0．932（P〈0．01）。结论 MR多序列综合扫描可对心脏瓣膜病特别是主动脉瓣疾病进行准确的定性及定量评价。     

MRI对累及头颈部淋巴组织病变的鉴别意义

目的:基于累及头颈部淋巴组织病变的临床不典型性,旨在探讨MRI对其进行鉴别诊断的客观依据。方法:对本组22例可疑累及头颈部淋巴组织的各类病变进行MRI检查并与病理学结果进行对照。结果:MRI对本组22例累及淋巴组织病变的诊断与病理学诊断的符合率(21/22)约为95%。结论:MRI是对累及头颈部淋巴组织病变的重要检查手段,并能为明确其诊断提供客观依据。     

Non-invasive temperature imaging of muscles with magnetic resonance imaging using spin-echo sequences

The application of spin-echo magnetic resonance imaging sequences on non-invasive temperature imaging for temperature mapping of human limbs is investigated. In an in vitro expriment performed on a meat sample, the equilibrium magnetisation P and the spin-lattice relaxation time T₁ are calculated from the values for the repetition time TR and the signal intensities obtained by a spin-echo sequence at different tissue temperatures tures as measured by a fibre-optic probe. T₁ is linearly correlated to the tissue temperature, and P is linearly correlated to the reciprocal value of the absolute temperature. Both effects, taken together, lead to a non-linear dependency of the signal intensity on temperature. Therefore a TR leading to maximum temperature dependency of the signal intensity is calculated and used in the futher experiments. In the in vivo experiments, the lower legs of two volunteers are cooled from outside. Images are acquired with a spin-echo sequence (1.5T, TR=1200 ms, TE=10 ms). A rise in signal intensity in the muscle with falling skin temperature is observed, particularly in more peripheral muscle layers. This study shows that spin-echo sequences can be used to monitor temperature changes and temperature differences in living muscle tissue.     

磁共振成像对颅内脑膜瘤水肿分析

目的：探讨脑膜瘤周围脑水肿的程度和肿瘤的生长部位．质地．组织学亚型的相关性．研究其瘤周水肿的形成原因．材料和方法：使用经手术和病理证实的65例脑膜瘤MRI和临床病理资料．观察分析脑膜瘤的瘤周水肿的程度．肿瘤的质地，组织学亚型等．结果：发生于大脑颅盖部或／和有矢状窦受累的脑膜瘤有明显的脑水肿．而发生于其它部位(颅底，丘脑、小脑、脑池等)无或只有轻度脑水肿．结论：轻度脑水肿主要是脑膜瘤对脑组织的直接压迫，而中，重度脑水肿主要是脑膜瘤对大脑表面引流静脉尤其是矢状窦的压迫或阻塞．脑水肿和肿瘤的发生部位有关，面和肿瘤的质地、组织学亚型无关．     

Gliomatosis cerebri with good prognosis

A 52-year-old man was admitted to our clinic with severe headache and bilateral papilledema. Magnetic resonance (MR) images on admission demonstrated diffuse swelling of the cerebral cortex without formation of a tumor mass. Biopsy revealed diffuse infiltration with neoplastic glial cells. After radiation and chemotherapy, the MR images returned to normal. The morphological and neurological features of the present case met the criteria for gliomatosis cerebri. However, this patient showed an unusually good response to radiation and chemotherapy.