磁共振灌注成像对肝癌介入治疗疗效评价研究

Objective: To investigate the value of MR perfusion imaging in evaluating the curative effect of intervention treat-ment of hepatic cancer. Methods: 36 patients underwent MR perfusion imaging after intervention treatment. The quantization results were differed between carcinoma residue and benign tissue. And the diagnosis accuracy was judged. Results: There was a significant difference in mean MSI between residue tumor after surgery and the benign enhancement area. The time-intension curve of residue tumor was observed to ascend rapidly to reach the peak, whereas that of the enhancement tissue ascended slowly to reach the peak. The sensitivity and specificity of PWI on detection of residuary or recurrent tumor were 0.89 and 0.73 respectively. Conclusion: PWI is a very sensitive imaging technique that can be used to distinguish liver tissue condition after surgery. PWI contributed to early stage diagnosis and dynamic monitoring following HCC surgery.     

短暂性脑缺血发作的脑电地形图与功能磁共振及血管病变的相关研究

目的观察短暂性脑缺血发作（TIA）患者间期脑电地形图（BEAM）变化情况,并与磁共振、血管病变对比,深入探讨TIA的病变机制。方法 18例颈内动脉系统TIA患者均行常规头MRI（T1WI、T2WI）、功能磁共振（DWI、PWI）,BEAM检查,综合磁共振血管成像（MRA）、数字减影脑血管造影（DSA）及颈动脉超声联合经颅多普勒超声（TCD,简称超声）检测判定血管病变并对上述结果进行分析。结果 BEAM病灶检出率94.4%,灌注加权成像（PWI）异常率70.6%,TCD异常率50%,DWI异常率16.7%。TIA间期BEAM广泛异常77.8%,责任病变部位集中于中央、顶部、前颞,主要表现为α频段较对侧功率降低,δ和θ频段较对侧功率增高。结论将BEAM和TCD/PWI相结合,可为TIA提供可靠的辅助检查。临床医生应重视TIA患者的神经保护治疗。     

The effects of glutamate receptor agonists and antagonists on mouse hypothalamic and hippocampal neuronal activity shown through manganese enhanced MRI

Manganese enhanced MRI (MEMRI) is an imaging paradigm that can be used to assess neuronal activity in vivo. Here we investigate, through the use of MEMRI, the influence of receptor dynamics on neuronal activity in the hypothalamus and hippocampus focusing on the glutamate receptor signalling system. We demonstrate that intraperitoneal (i.p.) administration of monosodium glutamate (MSG) and the ionotropic glutamate receptor (iGluR) agonists NMDA and AMPA resulted in significantly increased signal intensity (SI) in the arcuate nucleus (ARC), the suprachiasmatic nucleus (SCN) and the CA3 region of the hippocampus of mice consistent with increased neuronal activity. Administration of the NMDA receptor antagonist MK-801 resulted in significantly decreased SI in the paraventricular nucleus (PVN) consistent with decreased neuronal activity. Co-administration of MSG and the AMPA receptor antagonist NBQX attenuated the increase in SI observed in the ARC from MSG alone, suggesting MEMRI may be applicable to the study of receptor dynamics in vivo. We also observed that administration of the various iGluR agonists and antagonists modulated SI in the lateral ventricle and that high dose MSG (300 mg) caused a hitherto unseen enhancement in SI in the entire cortical/subarachnoid region. In conclusion, MEMRI reveals changes in neuronal activity in response to iGluR agonists and antagonists in the CNS in vivo as well as revealing multifaceted effects beyond those attributable to neuronal activity alone.     

Magnetic resonance imaging in neonatal encephalopathy

Magnetic resonance imaging may provide invaluable information in the term born neonate with encephalopathy. However, both hardware and sequences may need adaptation from normal adult protocols. Sedation is often required to obtain good quality imaging, but anaesthesia is not necessary in this population. The perinatal history may predict the pattern of brain lesions, which, in turn, may be used to predict the neurodevelopmental outcome. Image interpretation is not easy and requires a full clinical history in addition to experience of both normal and abnormal neonatal brain appearances. Lesions evolve rapidly, and perinatally acquired leasions are at the most obvious 1-2 weeks from delivery. Early imaging in the first few days from presentation should always include diffusion-weighted sequences to identify early ischaemic change. Advanced techniques such as venography, angiography and perfusion-weighted imaging may be useful in certain situations, and serial imaging may help differentiate perinatal-acquired lesions from other pathologies.     

灌注加权成像、磁敏感加权成像在高级别脑胶质瘤与单发脑转移瘤鉴别诊断中的价值

目的探讨灌注加权成像（PWI）、磁敏感加权成像（SWI）在高级别脑胶质瘤和单发脑转移瘤鉴别诊断中的应用价值．方法对术前进行过磁共振PWI与SWI检查并经病理证实的16例高级别脑胶质瘤与11例单发脑转移瘤进行回顾性分析．测量肿瘤实质区与周围水肿区的rCBV值,并以肿瘤SWI图像中低信号程度对两种肿瘤进行评分分析。结果16例高级别脑胶质瘤与11例单发脑转移瘤的肿瘤实质区rCBV值分别为9．87±2．76和10．97±2．12,差异无统计学意义（P〉0．05）;肿瘤周围水肿区rCBV值分别为1．99±0．50和1．12±0．23,差异有统计学意义（P〈0．05）。高级别脑胶质瘤组SWI低信号评分高于单发脑转移瘤组,以非参数Mann—WhitnevU检验进行统计学分析．差异有统计学意义（P〈0．05）。结论磁共振PWI及SWI有助于显示肿瘤及瘤周组织细微结构．对高级别脑胶质瘤和单发脑转移瘤的鉴别诊断有临床应用价值。     

Combined Intravenous and Intraarterial Revascularization Therapy Using MRI Perfusion/Diffusion Mismatch Selection for Acute Ischemic Stroke at 3–6 h After Symptom Onset

Background and Purpose  Intravenous (IV) thrombolysis with recombinant tissue plasminogen activator (rt-PA) has demonstrated favorable clinical outcomes in a 3–6 h window in patients selected with perfusion/diffusion mismatch. However, the advantages of combined IV and intraarterial (IA) thrombolysis after 3 h of stroke onset are unexplored. Methods  Acute ischemic stroke patients with persistent occlusion of intracranial large arteries were screened prospectively for thrombolysis by evaluating perfusion/diffusion mismatch on MRI. The IV rt-PA was initiated within 3–6 h, and additional urokinase (UK) was then administered via the IA route after angiography. Results  Four patients had middle cerebral artery occlusion and one patient had an internal carotid artery occlusion. The median time from the symptom onset to the initiation of IV therapy and to the initiation of IA treatment was 215 ± 30 min and 292 ± 41 min, respectively. The median National Institutes of Health Stroke Scale (NIHSS) scores were as follows: initial, 13; immediately after IA treatment, 8; at 24 h, 5; and at 7 days, 3. The Thrombolysis in Myocardial Infarction (TIMI) score after the completion of thrombolysis was 2–3. Four patients without intracerebral hemorrhage recovered completely or exhibited mild disability and one patient with hemorrhage also demonstrated a favorable outcome. Conclusion  This preliminary result suggests that if a significant perfusion/diffusion mismatch on MRI is identified, a sequential combination thrombolysis of IV rt-PA and IA UK is potentially beneficial in moderate to severe acute ischemic stroke patients who are treated within 3–6 h after symptom onset.     

Role of neuroimaging before reperfusion therapy. Part 1 – IV thrombolysis – Review

This review paper summarises the yield of the different imaging modalities in the evaluation of patients for IV thrombolysis. Non-contrast CT and CTA or brain MRI combined with MRA are the recommended sequences for the evaluation of patients within the 4.5 hours time window. Multimodal MRI (DWI/PWI), and more recently, CT perfusion, offer reliable surrogate of salvageable penumbra, the target mismatch, which is now currently used as selection criteria for revascularisation treatment in an extended time window. Those sequences may also help the physician for the management of other limited cases when the diagnosis of acute ischemic stroke is difficult. Another approach the DWI/FLAIR mismatch has been proposed to identify among wake-up stroke patients those who have been experiencing an acute ischemic stroke evolving from less than 4.5 hrs. Other biomarkers, such as the clot imaging on MRI and CT, help to predict the recanalisation rate after IVT, while the impact of the presence microbleeds on MRI remains to be determined.