DWI结合常规MRI在儿童病毒性脑炎中的应用

目的 探讨DWI在儿童病毒性脑炎诊断中的价值.方法 回顾性分析36例儿童病毒性脑炎的MR表现,分析病变部位、大小、在常规MRI序列及DWI序列上的信号强度及其与发病时间的关系.结果 病变主要呈长T1长T2信号,病变主要累及大脑皮层及基底节、丘脑.36例病例中有18例DWI显示病变范围及信号强化对比优于T2WI序列,平均发病时间约8.2天;有14例T2WI序列显示优于DWI序列,发病时间约12.6天;有4例病变在DWI及T2WI序列上显示大致相仿,发病时间约7.8天.结论 常规MRI及DWI对其不同阶段的病理改变显示优势各不相同,两种检查技术互补有利于对病毒性脑炎的早期、准确诊断.     

3.0MR多b值扩散加权成像在慢性肾衰肾功能方面的应用价值

目的研究3.0T MR扩散加权成像（DWI）测量ADC值与核医学99Tcm-DTPA肾显像测定的肾小球滤过率（GFR）之间的关系。方法对30例慢性肾功能衰竭的患者同时行3.0T MRI DWI和99Tcm-DTPA肾显像,DWI扫描采用b值为0、200、400、600、800、1 000 s/mm2,并测量肾皮质ADC值。根据GFR测量值将60个肾分为肾功能轻度受损组、肾功能中度受损组和肾功能重度受损组。比较3组ADC值是否存在统计学差异及ADC值同GFR的相关性。结果轻、中、重度受损组ADC值分别为（3.54±0.16）、（3.45±0.11）、（3.21±0.10）,各组肾脏ADC值间差异有统计学意义（P〈0.001）;其中轻、中度受损组与重度受损组间比较,肾脏ADC值多b值的差异均有统计学意义（均P〈0.001）;并且ADC值同GFR之间存在正相关性（r=0.623）。结论 3.0T MR多b值ADC值可评估肾脏滤过功能。     

基于DWI的影像组学列线图预测部分肝切除术后肝内胆管癌辅助化疗获益价值

目的 探讨基于弥散加权成像（DWI）的影像组学列线图（RN）预测肝内胆管癌（ICC）肝部分切除术（HPx）后辅助化疗（AC）获益人群的应用价值。方法 回顾性分析2018年1月—2022年1月我院行HPx的85例ICC患者的MRI和临床病理资料,分为训练集60例和验证集25例。用随机森林算法行基于DWI的影像组学特征筛选并建立预测早期复发（ER）的影像组学模型（RS）,并计算的影像组学评分。多因素Logistic回归法筛选临床、病理、常规影像中与ER相关变量建立临床-病理-影像（CPR）模型。筛选出的变量与影像组学评分构建临床-影像组学列线图（RN）,评估并验证上述模型的辨别度和校准度。用Kaplan Meier法和log-rank检验分析不同组预后差异。结果 验证集中,基于DWI的RS与CPR模型在预测ER有相似的区分性能（AUC：0.762 vs 0.624,P=0.271）,而RN模型（AUC：0.833）预测效能显著优于RS（P=0.012）。RN模型预测的ER高危组患者中,行手术+AC患者的OS与DFS较仅行接受手术治疗患者显著延长（DFS,P=0.035;OS,P=0.020)。结论 基于DWI的RN模型不仅可有效预测ICC患者术后发生ER,还可有效筛选术后AC获益人群     

双侧延髓内侧梗死临床分析

目的分析并探究双侧延髓内侧梗死(BMMI)的血管病因、临床表现、MRI特征和预后,以期提高BMMI的早期诊断率.方法对青岛大学附属烟台毓璜顶医院诊治的14例BMMI患者临床资料进行分析.结果BMMI血管病因以动脉粥样硬化为主;临床症状表现为四肢瘫痪、舌瘫、感觉异常、头晕、构音障碍、饮水呛咳等,危重时出现呼吸衰竭.头颅DWI示双侧延髓内侧可呈特征性"心型"、"Y"字型、"V"字型或倒"八"字型高信号影.出院NIHSS评分、卒中进展(尤其呼吸衰竭)为BMMI的预后不良因素.结论BMMI临床少见,临床表现多样,预后较差;头颅MRI为其主要的影像学检查,有助于早期诊断.     

Brain‐age estimation accuracy is significantly increased using multishell free‐water reconstruction

Although free‐water diffusion reconstruction for diffusion‐weighted imaging (DWI) data can be applied to both single‐shell and multishell data, recent finding in synthetic data suggests that the free‐water indices from single‐shell acquisition should be interpreted with care, as they are heavily influenced by initialization parameters and cannot discriminate between free‐water and mean diffusivity modifications. However, whether using a longer multishell acquisition protocol significantly improve reconstruction for real human MRI data is still an open question. In this study, we compare canonical diffusion tensor imaging (DTI), single‐shell and multishell free‐water imaging (FW) indices derived from a short, clinical compatible diffusion protocol (b = 500 s/mm², b = 1,000 s/mm², 32 directions each) on their power to predict brain age. Age was chosen as it is well‐known to be related to widespread modification of the white matter and because brain‐age estimation has recently been found to be relevant to several neurodegenerative diseases. We used a previously developed and validated data‐driven whole‐brain machine learning pipeline to directly compare the precision of brain‐age estimates in a sample of 89 healthy males between 20 and 85 years old. We found that multishell FW outperform DTI indices in estimating brain age and that multishell FW, even when using low (500 ms²) b‐values secondary shell, outperform single‐shell FW. Single‐shell FW led to lower brain‐age estimation accuracy even of canonical DTI indices, suggesting that single‐shell FW indices should be used with caution. For all considered reconstruction algorithms, the most discriminant indices were those measuring free diffusion of water in the white matter.     

Diffusion-weighted MRI and the evaluation of spinal cord axonal integrity following injury and treatment

Diffusion-based magnetic resonance imaging (MRI) (DWI) has been shown experimentally to detect both injury and functionally significant neuroprotection of injured spinal cord white matter that would otherwise go undetected with conventional MRI techniques. The diffusion of water in the central nervous system (CNS) is thought to be affected by both its location (intracellular or extracellular), and by diffusion barriers formed by cell membranes and myelin sheaths. There is, however, controversy concerning how to obtain, interpret, and present DWI data. Computer simulations and MR microscopy have been helpful in resolving some of these issues, as well as determining exact histologic correlates to DWI findings.     

小脑型分水岭梗死的临床分析和影像学特征

目的 探讨小脑型分水岭梗死临床特点及影像学特征.方法 回顾性分析32例病人的临床、CT和MRI资料.结果 小脑型分水岭梗死临床大多表现为头晕、头昏,头颅MRI、DWI(弥散加权成像技术)检查梗死灶阳性率为100%,行 MRA(磁共振血管成像)检查血管异常阳性率高,经治疗31例恢复良好,1例发展为进展性卒中而死亡.结论 颅内动脉的狭窄、变异和血流动力学改变与小脑型分水岭梗死关系密切,早期行DWI检查可以明确病灶部位,MRA技术可作为颅内血管的初筛检查,积极综合治疗可以改善小脑型分水岭梗死预后.     

DWI和3D-TOF法MRA在脑梗死中的诊断价值

目的探讨磁共振弥散成像(DWI)和3D-TOF法血管成像(MRA)在脑梗死中临床诊断价值,区分多发梗死灶中急性和非急性方面的能力,尤其是超早期脑梗死诊断和治疗中的作用。方法对72例脑梗死发病不同时间的病例行常规MRI、DWI序列及3D-TOF血管成像扫描,并根据发病时间进行分期比较及分析。结果MRI平扫T2加权像在发病12 h后才能隐约见到稍高信号的病灶,而DWI最早可在发病2 h发现缺血灶,3D-TOF血管成像不仅能显示脑动脉的狭窄、闭塞、动脉硬化还能显示侧枝循环情况。结论DWI可以明确诊断急性,尤其是超早期脑梗死,3D-TOF技术MRA可快速而准确地显示颅内动脉狭窄或闭塞及其相应的脑梗死,2者结合对治疗方案的制定与调整及评价疗效均有重要意义。     

Prostatic Artery Embolization with 250-μm Spherical Polyzene-Coated Hydrogel Microspheres for Lower Urinary Tract Symptoms with Follow-up MR Imaging

Purpose

To evaluate clinical outcomes and possible MR imaging predictors of clinical success after prostatic artery embolization (PAE) with 250-μm hydrogel particles.