咽旁间隙在头颈部肿瘤MRI诊断中的价值

目的探讨咽旁间隙移位方向及肿瘤MRI信号特点对病变定位、定性的价值。方法回顾性分析经病理确诊的累及咽旁间隙肿瘤76例,其中恶性肿瘤51例,良性肿瘤25例。结果扁桃体肿瘤和鼻咽癌使茎突前间隙外移,腮腺肿瘤使茎突前间隙向前内移位,或(和)颈动脉鞘区后移。颈动脉鞘区交感神经鞘瘤使颈内动、静脉向前外侧移位,迷走神经鞘瘤使颈内动、静脉明显分离,颈动脉体瘤使颈内、外动脉分叉角增大,颈静脉球瘤使血管向前外侧移位,转移淋巴结使颈内动、静脉向前内侧移位。25例良性肿瘤边界清楚,其中9例信号均匀;51例恶性肿瘤中,19例边界模糊,15例信号欠均匀。茎突前间隙脂肪消失或不连续6例均为恶性肿瘤,肿瘤边界较清但颈部淋巴结肿大符合淋巴结转移诊断标准2例及颈内动、静脉被肿瘤包绕3例,病理证实亦为恶性肿瘤。结论咽旁间隙移位方向及肿瘤MRI信号特点对头颈部肿瘤的定位、定性具有重要的价值。     

老年性骨质疏松脊柱良性骨折与转移瘤性骨折的MRI鉴别

目的探讨脊椎骨质疏松性压缩骨折的MRI表现及其与转移性压缩骨折的鉴别诊断.资料与方法回顾性分析53例老年性骨质疏松伴压缩性骨折和20例转移性椎体压缩骨折患者的MRI资料.全部病例均行常规MRI检查(矢状位、横轴位).分析两者引起的压缩骨折MRI征象,包括椎体和椎弓根的形态及信号改变、椎间盘增厚、椎体内真空现象和椎旁软组织形态.探讨两者之间的差别.结果两者在椎体和椎弓根形态及信号、椎体内真空现象、椎旁软组织形态上存在非常显著性差异(P＜0.01).结论 MRI能准确显示骨质疏松性压缩骨折的形态及信号,与转移瘤之间有显著差异,大多能对二者做出鉴别诊断.     

MR灌注成像在评估脑胶质瘤放疗效果中的应用

目的探讨MR灌注成像在评估脑胶质瘤放疗疗效中的应用价值。方法对25例脑胶质瘤术后患者于放疗前及放疗后3、6个月行MR灌注成像及常规MRI检查。由灌注数据获取脑血容量（CBV）图和脑血流量（CBF）图。计算出病灶的最大相对局部脑血容量（rCBV）值和最大相对局部脑血流量（rCBF）值。结果25例脑胶质瘤术后放疗前肿瘤区的rCBV值和rCBF值分别为6．32±2．14和5．49±1．98，与正常脑组织的2．58±1．21和2．17±1．19相比，显著升高（P〈0．01）。其中11例放疗后rCBV值和rCBF值与放疗前相比，显著下降（P〈0．01），其中5例证实为放射性脑坏死；另14例放疗后rCBV值和rCBF值与放疗前相比，有不同程度升高，但无统计学意义（P〉9．05）。其中7例证实为肿瘤伴部分放射性坏死组织，2例死亡，5例再次行放射治疗取得较好疗效。结论MR灌注成像可作为评估脑胶质瘤放疗疗效的一项重要指标。并有助于下一步治疗方案的制定。     

瘤蒂征在MRI诊断小脑桥脑角听神经瘤中的价值

听神经瘤是小脑桥脑角的常见、多发肿瘤,但有时易与其他肿瘤混淆.本研究分析了19例经手术病理证实的小脑桥脑角听神经瘤MRI表现,探讨"瘤蒂征"对小脑桥脑角听神经瘤的诊断价值.     

Smaller hippocampal volume in patients with recent-onset posttraumatic stress disorder.

BACKGROUND: Previous structural magnetic resonance (MR) research in patients with posttraumatic stress disorder (PTSD) has found smaller hippocampal volumes in patients compared with control subjects. These studies have mostly involved subjects who have had PTSD for a number of years, such as war veterans or adult survivors of childhood abuse. Patients with recent-onset PTSD have rarely been investigated. To our knowledge only one other study has investigated such a group. The aim of this study was to compare hippocampal volumes of patients with recent onset PTSD and nontrauma-exposed control subjects. METHODS: Fifteen patients with PTSD, recruited from an accident and emergency department, were compared with 11, non-trauma-exposed, healthy control subjects. Patients underwent a structural MR scan soon after trauma (mean time = 158 +/- 41 days). Entire brain volumes, voxel size 1 x 1 x 1 mm, were acquired for each subject. Point counting and stereology were used to measure the hippocampal and amygdala volume of each subject. RESULTS: Right-sided hippocampal volume was significantly smaller in PTSD patients than control subjects after controlling for effects of whole brain volume and age. Neither left nor total hippocampal volume were significantly smaller in the PTSD group after correction. Whole brain volume was also found to be significantly smaller in patients. There were no differences in amygdala or white matter volumes between patients and control subjects. CONCLUSIONS: This result replicates previous findings of smaller hippocampal volumes in PTSD patients, but in an underinvestigated population, suggesting that either smaller hippocampal volume is a predisposing factor in the development of PTSD or that damage occurs within months of trauma, rather than a number of years. Either of these two hypotheses have significant implications for the treatment of PTSD. For instance, if it could be shown that screening for hippocampal volume may, in some cases, predict those likely to develop clinical PTSD.     

深部脑白质缺血影像表现与MTHFR基因多态性关系的探讨

目的：探讨MTHFR的纯合突变TT型基因是否为诱发皮层下深部脑白质缺血的危险因子，并证实皮层下深部脑白质缺血影像表现与MTHFR基因C／T多态性的关系。资料与方法：选择影像表现符合皮层下深部脑白质缺血诊断标准者30例，对照组30例为影像表现正常者，运用多聚酶链反应－限制性内切酶片段长度多态性技术（PCR－RFLP）检测两组MTHFR基因多态性。结果：采用χ^2检验，得出MTHFR基因纯合突变TT型在病变组与对照组比较差异有显著性（χ^2=5.0794,P＜0．05），病变组TT型较对照组显著升高，说明MTHFR的纯合突变TT型可能是诱发深部脑白质缺血的危险因素。运用成组设计两样本比较的秩和检验，得出TT型和非TT型患者在影像表现的分级程度上有差别，携带TT型基因者影像表现分级重。结论：MTHFR纯合突变TT型基因是深部脑白质缺血发病的危险因子，且TT型基因与深部脑白质缺血的易感性和影像表现呈明显正相关。     

脊柱放线菌感染并发脊髓压迫症(附3例报告)

目的探讨脊柱放线菌感染并发脊髓压迫症的临床和影像学特点及治疗方法。方法回顾性分析3例经病理检查证实的本病患者的临床资料。结果3例患者均有颈、胸脊椎及软组织感染和脊髓压迫症状;MRI示病变椎体骨质破坏,颈、胸硬膜外软组织肿块,脊髓受压。病理学检查组织病理学检查证实3例均为放线菌感染,2例表现为炎性肉芽组织伴微脓肿形成,另1例表现为硬膜外脓肿。均予以脓肿清除、脊髓减压术,并给予4~8周大剂量青霉素G静脉滴注,后改口服维持4~6个月,术后及随访3例患者均取得显著的疗效。结论脊柱放线菌感染并发脊髓压迫症临床和影像学表现无特征性,其确诊依赖于病理学和微生物学检查。脓肿引流、椎管内减压术和大剂量抗生素治疗有效。     

椎动脉狭窄76例TCD频谱分析

经颅多谱勒超声诊断仪 (TCD)是一种较为普及的脑血流检测仪 ,具有灵敏度高 ,穿透力强 ,不受声束方向限制的检测工具。为了明确它对椎动脉狭窄诊断的特殊价值 ,我们对核磁共振 (MRI)提示的 76例 (96支 )椎动脉不同程度狭窄的病例 ,又经 TCD检测 ,并对其频谱形态、血流参数进行分析比较 ,现报告如下。1　临床资料1.1　一般资料 :通过 MRI提示椎动脉狭窄血管 76例(96支 )。其中 ,男 4 8例 ,女 2 8例。年龄 <4 0岁 16例 ,4 0～ 5 0岁 2 5例 ,5 0岁 35例。将 MRI所测血管内径分成 3组 ,内径 <4 .0 mm为轻度狭窄 ,内径在 3.0～ 3.5 mm为中度…     

原发性眼眶静脉曲张的CT和MRI表现

目的探讨原发性眼眶静脉曲张(POV)的CT及MRI表现。方法临床诊断的30例原发性眼眶静脉曲张患者,9例行CT横断位和冠状位扫描,21例行MR扫描,4例行CT和MR检查。结果30例中30只患眼,左眼18例,右眼12例,均为单侧发病。病变部位眼睑3例,眼眶前部1例,眼眶后部(球后)17例,眼睑和眼眶前部5例,眼睑、眼眶前部和眼眶后部2例,眼眶前部和眼眶后部2例。形态17例为不规则块状,4例为卵圆形,9例为不规则条状。CT冠状位,病变均显示为软组织密度,有明显强化;静脉石2例;眶骨受压变薄、眶腔扩大3例。MR扫描,颈部加压后25例均显示病变,11例呈等T1长T2信号,7例呈长T1长T2信号,1例呈等T1等T2信号,6例呈长T1长T2为主的混杂信号,增强的22例中,14例呈明显均匀强化,8例呈不均匀强化。结论CT横断位和冠状位及颈部加压或俯卧位MRI在原发性眼眶静脉曲张的诊断和鉴别诊断方面有重要价值。     

RASER: a new ultrafast magnetic resonance imaging method.

A new MRI method is described to acquire a T(2)-weighted image from a single slice in a single shot. The technique is based on rapid acquisition by sequential excitation and refocusing (RASER). RASER avoids relaxation-related blurring because the magnetization is sequentially refocused in a manner that effectively creates a series of spin echoes with a constant echo time. RASER uses the quadratic phase produced by a frequency-swept chirp pulse to time-encode one dimension of the image. In another implementation the pulse can be used to excite multiple slices with phase-encoding and frequency-encoding in the other two dimensions. The RASER imaging sequence is presented along with single-shot and multislice images, and is compared to conventional spin-echo and echo-planar imaging sequences. A theoretical and empirical analysis of the spatial resolution is presented, and factors in choosing the spatial resolution for different applications are discussed. RASER produces high-quality single-shot images that are expected to be advantageous for a wide range of applications.