磁共振动脉自旋标记技术对阿尔茨海默病脑血流量的初步研究

目的 探讨磁共振动脉自旋标记(arterialspinlabeling,ASL)技术对显示阿尔茨海默病(AD)患者脑血流异常的临床应用价值.方法 22例AD患者和20例年龄相匹配的健康对照者进行头颅ASL灌注成像和磁共振形态学检查,其中16例AD患者及11例健康对照者完成了脑单光子发射计算机断层扫描(singlephotonemissioncomputedtomography,SPECT)检查.ASL灌注的原始数据经处理后得到脑血流图,测量双侧额叶、颞叶、颞顶交界区、顶叶和枕叶皮质和海马区的脑血流量,并比较AD患者脑血流量与健康对照者的差异.结果 22例AD患者ASL脑灌注图像均可见局部皮质灌注减低区,主要为颞叶72.7%(16例)、颞顶交界54.5%(12例)和顶叶45.5%(10例),且与SPECT表现一致.AD患者双侧额叶、颞叶、颞顶交界区、顶叶皮质及海马区的脑血流量较健康对照者显著下降(均P<0.05).AD患者右额叶、左顶叶及左颞顶交界皮质的脑血流量与简短精神状态量表(mini-mentalstateexamination,MMSE)评分呈正相关(r分别为0.49、0.54和0.64,均P<0.05).结论 ASL不仅可以清晰显示AD患者局部脑血流减低区,而且表现与SPECT一致,提示ASL技术是一种评价AD患者脑血流下降的有效工具.     

磁共振动脉自旋标记技术对阿尔茨海默病脑血流量的初步研究

目的 探讨磁共振动脉自旋标记(arterialspinlabeling,ASL)技术对显示阿尔茨海默病(AD)患者脑血流异常的临床应用价值.方法 22例AD患者和20例年龄相匹配的健康对照者进行头颅ASL灌注成像和磁共振形态学检查,其中16例AD患者及11例健康对照者完成了脑单光子发射计算机断层扫描(singlephotonemissioncomputedtomography,SPECT)检查.ASL灌注的原始数据经处理后得到脑血流图,测量双侧额叶、颞叶、颞顶交界区、顶叶和枕叶皮质和海马区的脑血流量,并比较AD患者脑血流量与健康对照者的差异.结果 22例AD患者ASL脑灌注图像均可见局部皮质灌注减低区,主要为颞叶72.7%(16例)、颞顶交界54.5%(12例)和顶叶45.5%(10例),且与SPECT表现一致.AD患者双侧额叶、颞叶、颞顶交界区、顶叶皮质及海马区的脑血流量较健康对照者显著下降(均P<0.05).AD患者右额叶、左顶叶及左颞顶交界皮质的脑血流量与简短精神状态量表(mini-mentalstateexamination,MMSE)评分呈正相关(r分别为0.49、0.54和0.64,均P<0.05).结论 ASL不仅可以清晰显示AD患者局部脑血流减低区,而且表现与SPECT一致,提示ASL技术是一种评价AD患者脑血流下降的有效工具.     

原发性进行性失语的磁共振研究(附一例病例分析)

目的报道1例原发性进行性失语患者的脑内影像学特点,以探讨原发性进行性失语患者常见的病变部位,脑内血流量、代谢及语言功能区之间联系纤维的变化。方法利用西门子3.0T磁共振仪对1例确诊失语类型为感觉性失语的原发性进行性失语患者进行(1)常规磁共振;(2)磁共振灌注成像;(3)磁共振波谱分析;(4)磁共振扩散张量成像分析。结果常规磁共振成像显示左侧额叶及颞叶萎缩,功能磁共振显示左侧颞叶和额叶前部代谢较对侧明显减低,左侧颞极及额前部的血流量较对侧减低;左侧皮质脊髓束部分各向异性值及追踪到的纤维束较对侧减少,Broca区与Wernicke区之间的联系纤维与对侧相比减少。结论原发性进行性失语病变的部位主要在左侧颞叶、额叶,与对侧相应区域对比呈现低灌注、低代谢状态,Broca区与Wernicke联系纤维减少。     

单光子发射计算机断层扫描在系统性红斑狼疮中枢神经系统病变中的诊断价值

目的 评价单光子发射计算机断层扫描(single photon emission computed tomography，SPECT)在系统性红斑狼疮中枢神经系统病变(CNS-SLE)诊断中的应用价值。方法 对21例SLE患者进行SPECT检查，并由2名以上经过训练且不知晓患者病情的核医学医师进行独立读片，明确脑血流灌注异常部位。对10例CNS-SLE患者同时行头颅CT和，或核磁共振(MRI)检查。结果 10例CNS-SLE中9例头颅SPECT阳性(阳性率90％)，同时行头颅CT／MRI检查仅4例阳性(阳性率40％)。9例均为中～重度血流灌注减低，9例均有额叶和，或顶叶受累(6例额叶受累，4例顶叶受累，5例基底节受累，1例颞叶受累，0例枕叶受累，7例为多个区域受累)。对其中3例CNS-SLE患者治疗前后SPECT表现进行比较，发现经有效治疗临床症状改善后，SPECT异常随之明显改善甚至完全消失。11例非CNS-SLE中，仅2例SPECT阳性(阳性率18％)，且均为轻度单一区域血流灌注减低(1例枕叶，1例基底节)，无一例有额叶或顶叶受累。结论 SPECT对于CNS-SLE是一种敏感的检测手段，对监测病情变化、指导治疗有重要的参考价值；SLE患者头颅SPECT表现多发病灶、有额叶和(或)顶叶受累及中～重度血流灌注减低提示有CNS受累。     

皮质基底节变性的临床和病理研究

目的：阐述皮质基底节变性的临床和病理特征。方法：报告2例皮质基底节变性的临床资料和病理检查结果。结果：2例病人早期表现为单侧肢体运动障碍如肌张力增高,跌倒发作,病程中出现四肢强直少动,伴肌阵挛和不同程度的皮层认知功能障碍;影像学表现为额顶叶不对称性萎缩或脑代谢减低。大体见普遍脑萎缩,但以额、顶叶皮层为著,镜下检查见皮层气球样神经元,基底节和黑质神经细胞变性脱失。Gallyas-Braak 银染色和Tan免疫组织化学染色显示基底节、黑质等神经元胞质内Tan阳性球形包涵体,额叶、顶叶皮层及基底节大量Tan阳性簇状星形胶质细胞和星形胶质细胞斑。结论：老年人慢性进展性不对称肢体运动障碍伴痴呆时,临床应用考虑到皮质基底节变性。如病理上发现特异性神经元及星形胶质细胞改变,则有助于本病的确诊。     

Biochemical changes in the frontal lobe of HIV-infected individuals detected by magnetic resonance spectroscopy

We have developed a proton magnetic resonance spectroscopy method that selectively can sample cortical gray matter and adjacent white matter in the frontal lobe. We have used this approach to study a group of patients (n = 7) infected with HIV and clinical manifestations of the AIDS dementia complex (ADC), a group of patients (n = 8) infected with HIV without any indications of ADC, and seven controls. The patients without ADC had a statistically significant increase in the ratio of myo-inositol to creatine in white matter compared with normal controls. In contrast, the group of patients with ADC had almost normal levels of myo-inositol to creatine in both gray matter and white matter and showed a statistically significant decrease in the N-acetylaspartate to creatine ratio in gray matter compared with either the normal controls or the patients without ADC. Patterns of spectral abnormalities correlated with neuropsychological measures of frontal lobe dysfunction, suggesting that the evaluation of frontal lobe metabolism by magnetic resonance spectroscopy can play a role in the early detection of ADC, in determining its progression, and in assessing responses to therapeutic interventions.     

Advance prediction of Mild Cognitive Impairment (MCI) using (99m)Tc-ECD SPECT brain blood flow imaging

AIM: Mild Cognitive Impairment (MCI) is considered as a precursor state of Alzheimer disease (AD). SPECT brain blood flow imaging was investigated in MCI and it's relevance to the prognosis of MCI was evaluated in an attempt define the characteristics of brain blood flow imaging of MCI (amnestic MCI; aMCI) converting to AD. METHODS: Ninety-two patients over 60 years old with amnesia were studied. (99m)Tc-ECD SPECT brain blood flow examinations of the subject under drug-free conditions were conducted and imaging was analyzed according to the first clinical diagnosis. Patients given a diagnosis of MCI on the first clinical diagnosis, were examined again after 2 years and the SPECT imaging before 2 years previously was classified and analyzed. RESULTS: Of them, there were 35 MCI patients, converting of 13 AD patients (37.1%; aMCI), 10 MCI patients (28.6%; non-converter), 4 depression patients (11.4%; Depression type MCI (dMCI)), 1 Geriatric psychosis patient, but 7 patients dropped out. In the aMCI group, relative hypoperfusion was recognized in the posterior cingulate and the precuneus. In the dMCI group, relative hypoperfusion was recognized in the dorsolateral prefrontal cortex (DLPFC) and the anterior cingulate. In the non-converter group, relative hypoperfusion was recognized in the basal forebrain. CONCLUSIONS: The hypoperfusion of the precuneus in aMCI, and the hypoperfusion of the right frontal lobe (DLPFC, dorsal-anterior cingulate) in dMCI were characteristic brain blood-flow abnormalities. We believe (99m)Tc-ECD SPECT brain blood flow imaging to be useful in the diagnosis of aMCI and in the early detection of depression.     

应用动脉自旋标记技术分析阿尔茨海默病脑血流灌注成像的研究

目的应用脉冲动脉自旋标记技术,分析阿尔茨海默病(AD)患者脑血流灌注的改变情况。方法采集静息状态下17例AD患者(AD组)及17例健康志愿者(对照组)动脉自旋标记的灌注成像数据,计算其相对脑血流量。结果与对照组比较,AD组患者双侧颞叶、左侧额叶、双侧顶叶、双侧枕叶及左侧丘脑的相对脑血流量均有下降。结论动脉自旋标记的灌注成像为检测AD患者异常灌注改变提供了一种有价值的方法,AD患者的低灌注与其脑结构和功能的改变密切相关。     

Schizophrenic symptoms and SPECT abnormalities in a coeliac patient: regression after a gluten-free diet

De Santis A, Addolorato G, Romito A, Caputo S, Giordano A, Gambassi G, Taranto C, Manna R, Gasbarrini G (Catholic University, Rome, Italy). Schizophrenic symptoms and SPECT abnormalities in a coeliac patient: regression after a gluten-free diet (Case Report). J Intern Med 1997; 242 : 421–23.
A 33-year-old patient, with pre-existing diagnosis of 'schizophrenic' disorder, came to our observation for severe diarrhoea and weight loss. Use of single photon emission computed tomography, (^99mTc)HMPAO SPECT, demonstrated hypoperfusion of the left frontal brain area, without evidence of structural cerebral abnormalities. Jejunal biopsy showed villous atrophy. Antiendomysial antibodies were present. A gluten-free diet was started, resulting in a disappearence of psychiatric symptoms, and normalization of histological duodenal findings and of (^99mTc)HMPAO SPECT pattern. This is the first case in which, in an undiagnosed and untreated coeliac patient with psychiatric manifestations, the (^99mTc)HMPAO SPECT demonstrated a dysfunction of frontal cortex disappearing after a gluten-free diet.     

A Japanese case with Nasu-Hakola disease of DAP12 gene mutation exhibiting precuneus hypoperfusion

A 38-year-old Japanese man with Nasu-Hakola disease (NHD) had repeated pathological fractures and frontal lobe symptoms which developed when he was 18 and 26 years old, respectively. Neuropsychological testing showed memory impairment, and in particular, visuo-spatial memory at the age of 35. Furthermore, single-photon emission computed tomography revealed precuneus hypoperfusion. The patient later suffered prolonged convulsive seizures, which left him in a persistent vegetative state. Genetic testing confirmed a heterozygous mutation in the DAP12 gene (a single-base deletion of 141 G in exon 3) specific to NHD. Precuneus dysfunction might contribute to characteristic memory impairment of NHD.     

A case of corticobasal degeneration that progressed from primary progressive aphasia

A 65-year-old woman began to experience slowly progressive speech disturbance from 2001. She was admitted to our hospital for examination on May 2003. She had dysprosody, paragraphia, and mild disturbance in comprehension of spoken language. Repetition was preserved. No clear paraphasia was found. Calculation was disturbed, but there were no other neurological abnormalities including apraxia and agnosia. Brain MRI showed atrophy of the left frontal and parietal lobes. 99mTc-ECD SPECT showed decreased blood flow in the left frontal lobe and parietal lobe, especially in the Broca area and supplemental motor cortex. Primary progressive aphasia was diagnosed, because aphasia lasted for 2 years without other neurological deficits, and her daily activity was well preserved. During follow up, facial apraxia appeared from December 2003, and limb apraxia appeared from May 2004, followed by rigidity predominantly in the right upper limb and dementia. She was diagnosed as having corticobasal degeneration (CBD). The second SPECT on December 2004 showed progression of the decrease in cerebral flow at the same area showed by the first SPECT. SPECT is useful examination to predict the progress of the disease because the decrease of blood flow was recognized before the progression to CBD.     

The impact of hypertension on cerebral perfusion and cortical thickness in older adults

Hypertension may increase risk for dementia possibly because of its association with decreased cortical thickness. Disturbed cerebral autoregulation is one plausible mechanism by which hypertension impacts the cerebral structure, but the associations among hypertension, brain perfusion, and cortical thickness are poorly understood. The current sample consisted of 58 older adults with varying levels of vascular disease. Diagnostic history of hypertension and antihypertensive medication status was ascertained through self-report, and when available, confirmed by medical record review. All participants underwent arterial spin labeling and T1-weighted magnetic resonance imaging to quantify total and regional cortical perfusion and thickness. Analysis of covariance adjusting for medical variables showed that participants with hypertension exhibited reduced temporal and occipital brain perfusion and total and regional cortical thickness relative to those without hypertension. The effects of hypertension on total brain perfusion remained unchanged even after adjustment for age, although no such pattern emerged for cortical thickness. Decreased total brain perfusion predicted reduced thickness of the total brain and of the frontal, temporal, and parietal lobe cortices. Antihypertensive treatment was not associated with total cerebral perfusion or cortical thickness. This study provides initial evidence for the adverse effects of a diagnostic history of hypertension on brain hypoperfusion and reduced cortical thickness. Longitudinal studies are needed to investigate the role of hypertension and its interaction with other contributing factors (eg, age) in the manifestation of cerebral hypoperfusion and reduced cortical thickness.     

The Significance of Family History Status in Relation to Neuropsychological Test Performance and Cerebral Glucose Metabolism Studied with Positron Emission Tomography in Older Alcoholic Patients

Patients with severe chronic alcoholism have decreased rates of glucose metabolism in the medial frontal lobe and correlated abnormalities of neuropsychological functioning. The potential influence of family history of alcoholism has not been examined in these patients. In a retrospective study, we used neuropsychological tests and neuroimaging employing [¹⁸F]fluorodeoxyglucose with positron emission tomography to study 48 older subjects who had histories of severe, chronic alcohol dependence. These patients were divided into two groups: 27 with a first-degree relative with chronic alcoholism and 21 patients without first-degree relative with chronic alcoholism. No differences were found between groups on either neuropsychological or neuroimaging tests. These results suggest that a family history of alcoholism does not moderate the damaging effects of severe chronic alcoholism on the functioning of the medial frontal lobe.     

Good correlation between cerebral oxygenation measured using near infrared spectroscopy and stump pressure during carotid clamping.

AIM: Intraoperative hypoperfusion ischemia is one factor that leads to perioperative stroke during carotid endarterectomy. Selective shunting is one way to reduce intraoperative hypoperfusion, but to shunt selectively needs a sensitive and simple monitoring system together with the rules for insertion. Near infrared spectroscopy (NIRS) is a monitoring system that can be used throughout the operation, and reflects the cerebral oxygenation instantly, but its value in insertion of shunt tubes is still controversial. The aim of this study was to determine criteria that can be used to insert shunt tubes. METHODS: Forty-three consecutive patients with severe carotid stenosis undergoing carotid artery surgery with NIRS monitoring were enrolled in the study. Under general anesthesia, the optodes of NIRS were placed bilaterally on the forehead. Throughout the operation, regional saturation of the frontal lobe (SdO2) was monitored every 5 s. RESULTS: All operations were performed without any perioperative deaths. NIRS showed that SdO2 fell rapidly as soon as the artery was cross-clamped, and reached the lowest level after 60 s. SdO2 change at 60 s and the stump pressure showed good correlation (r=0.65), and stump pressure of 40 mmHg was almost equivalent to 5% SdO2 decrease in NIRS. CONCLUSION: NIRS monitoring is suitable for monitoring during carotid endarterectomy for selective shunting, because it can be used throughout the operation and shows the immediate change in oxygenation. There is a possibility that a decrease of 5% can be used as a decisive value for shunt insertion.     

血管性痴呆大鼠脑血流量及细胞凋亡的研究

目的　研究脑血流量及细胞凋亡在血管性痴呆 (VD)发病机制中的作用。方法　采用双侧颈总动脉永久结扎方法制备前脑缺血致血管性痴呆动物模型 ,利用激光多普勒血流仪检测各组大鼠术后不同时间点 (术后 2 4h、1周、0 .5、1、2、3及 4个月 )额叶皮质、海马区局部脑血流量 (rCBF) ;采用HE染色、光镜观察各组大鼠脑组织的形态学变化 ;采用流式细胞仪 (FCM) ,观察额叶皮质、海马区神经细胞凋亡时程变化情况。结果　大鼠术后额叶皮质、海马区的rCBF明显下降 ,以术后 2 4h最明显 ,至术后 4个月时仍明显低于正常 ;病理学研究发现 ,少数大鼠出现脑梗死灶。随着脑血流量持续下降 ,额叶皮质经历了从锥体细胞水肿、缺血、凝固性坏死到变性、脱失及星形胶质细胞增生的过程 ;海马CA1区锥体细胞从最初的缺血、水肿逐渐发展为严重脱失、基质疏松及微空泡形成。FCM结果显示 ,额叶皮质及海马区细胞凋亡均在 1周时最明显 ,额叶皮质至术后 2个月、海马区至术后 3个月时仍明显高于对照组。海马区凋亡细胞百分率明显高于额叶皮质。结论　持续性脑血流量下降引起神经细胞凋亡是导致血管性痴呆的主要原因之一。     

Diffusion tensor imaging in refractory epilepsy

Diffusion tensor imaging is an imaging method that is sensitive to the molecular movement of water, which indicates cellular integrity and pathology. A patient with refractory epilepsy and normal conventional MRI was examined with diffusion tensor imaging. An area of abnormal diffusion in the right frontal lobe was identified and surgically resected. The patient had a good clinical outcome. Histopathological examination of the resected tissue showed gliosis. Our findings may affect the investigation of similar patients, and provide histopathological confirmation of diffusion abnormalities.     

Orthostatic hypotension in Alzheimer's disease: result or cause of brain dysfunction?

In Alzheimer's disease (AD), an association was found between autonomic dysfunction and frontal hypoperfusion in brain during orthostatic testing. To ascertain whether frontal hypoperfusion is dependent on longitudinal effects of hemodynamic disturbances, or contributes to them, we studied the relationship between the presence of orthostatic hypotension (OH) and resting cerebral blood flow (CBF) in late stages of AD. Twelve women with senile dementia of Alzheimer type (SDAT), and 15 non-demented women (mean age 82.6 years, SD 3.8 vs 81.8 years, SD 3.5) were examined with the orthostatic test. Four of 12 patients with SDAT, and 9 controls had OH (defined as systolic blood pressure fall > or = 20 mmHg). CBF was determined under resting conditions using 600 Mbq 99mTc HMPAO single photon emission computerized tomography (SPECT), and quantified in cortical areas in relation to cerebellum. In patients with SDAT and OH, CBF was lower in frontal and parieto-frontal cortical areas than in SDAT patients without OH. The former group was younger and had a shorter dementia duration. No significant differences in CBF were observed between controls with vs without OH. No differences in SDAT patients with or without OH were observed in the Berger dementia scale or Katz' ADL index. No difference in incidence of symptoms related to autonomic disturbances (diarrhea, obstipation, dysphagia, vertigo) was observed in either the SDAT or control group with regard to OH presence. We conclude that during the course of AD, OH can contribute to frontal brain changes and may exacerbate the disease. The further involvement of frontal dysfunction in aggravating blood pressure dysregulation in the elderly is discussed.     

Diagnostic value of single-photon-emission computed tomography in severe central nervous system involvement of systemic lupus erythematosus: a case-control study

OBJECTIVE: To evaluate the diagnostic value of single-photon-emission computed tomography (SPECT) in severe central nervous system (CNS) involvement of systemic lupus erythematosus (SLE). METHODS: Forty-three patients with SLE, including 22 with CNS-SLE and 21 with non-CNS-SLE, underwent SPECT and magnetic resonance imaging (MRI) examinations. SPECT was repeated 1-2 months after treatment in patients with abnormal findings. RESULTS: SPECT and MRI abnormalities were detected in 20 (90.9%) and 10 (45.5%) of the 22 patients with CNS-SLE, respectively (P < 0.01). For 4 patients with cerebral infarction or hemorrhage, SPECT was equally as sensitive as MRI (100%). For the patients with CNS-SLE with diffuse presentations, SPECT was more sensitive than MRI in revealing abnormalities (16 [88.9%] of 18 patients versus 6 [33.3%] of 18 patients; P < 0.01). In 19 (95.0%) patients, the abnormal SPECT finding manifested as moderate to severe perfusion defect (15 in frontal lobe, 11 in parietal lobe, 11 in basal ganglia, 3 in temporal lobe, and 17 in multiple regions). Although mild perfusion defect was also detected in 4 (19.0%) of the patients with non-CNS-SLE, it only involved a single region and spared the frontal and parietal lobes. Repeated SPECT after treatment showed that perfusion defect had improved significantly or even disappeared in 11 (84.6%) of 13 patients with diffuse CNS-SLE with abnormal findings before treatment. CONCLUSION: Moderate to severe perfusion defect in SPECT involving multiple regions, especially in the frontal and parietal lobes and basal ganglia, in patients with lupus suggests CNS involvement. SPECT is more sensitive than MRI in revealing damage in diffuse CNS-SLE, and is useful in followup, especially for monitoring disease severity and guiding treatment.     

Diagnostic accuracy of single photon emission CT in Alzheimer-type dementia]

To determine the diagnostic accuracy of single photon emission computed tomography (SPECT) with 123I-IMP in Alzheimer-type dementia (ATD), we studied 46 ATD patients and 23 healthy controls. The patients fulfilled the NINCDS-ADRDA criteria for probable or definite ATD and were classified as having mild, moderate, and severe ATD by neuropsychological examinations. To assess regional cerebral blood flow, we performed qualitative SPECT image analysis without any knowledge of the subject's clinical classification. The image was regarded as abnormal if cerebral blood flow was reduced in the unilateral or bilateral temporoparietal association areas, with or without any reduction of flow in other brain regions. The diagnostic sensitivity (abnormal image/patient) of 123I-IMP SPECT in mild, moderate, and severe ATD was 67%, 86%, and 92%, respectively. The specificity (normal image/control) was 91%, because an abnormal image was found in only 2/23 healthy controls. Eight ATD patients without reduced temporoparietal perfusion showed normal perfusion or frontal hypoperfusion. These results suggest that 123I-IMP SPECT may provide an accurate and sensitive diagnostic marker for ATD. The detection of these characteristic marker for ATD. The detection of these characteristic abnormalities of cerebral perfusion could well be applied to the clinical diagnosis of ATD.     

Amitriptyline and lorazepam improved catatonia and occipital hypoperfusion in a patient with DLB

A 76-year-old woman presented with catatonia, refusal to eat due to delusion, and visual hallucination. Single photon emission computed tomography showed remarkable occipital hypoperfusion and frontal hyperperfusion. (123)I metaiodobenzyl guanidine myocardial scintigraphy revealed decreased uptake. She was diagnosed as probable dementia with Lewy bodies (DLB). Intravenous or oral L-dopa had no effect on catatonia. Amitriptyline and lorazepam improved catatonia and visual hallucination. Cerebral blood flow of the frontal and occipital lobes seemed to be normalized. Occipital hypoperfusion is one of the features of DLB. Although the mechanism of perfusion abnormality in DLB remains to be clarified, our case suggested that it might be reversible.