基于体素的动脉自旋标记成像在遗忘型轻度认知障碍患者脑血流灌注中的应用研究

目的 利用动脉自旋标记法探讨遗忘型轻度认知障碍者(aMCI)的脑血流灌注特征.方法 选择年龄、性别匹配的17例aMCI患者和21名健康老年人,采用三维动脉自旋标记序列进行灌注成像.采用SPM8对灌注加权影像进行基于体素分析方法分析,统计采用t检验分析.结果 与正常老年组相比aMCI组脑血流灌注减低的区域主要包括左侧枕叶、双侧颞下回、右侧颞中回和右侧顶叶上部,而灌注增加区域则集中在双侧额叶及右侧颞叶的皮质下区.结论 研究揭示了aMCI患者脑异常灌注区域,尤其是局部的高灌注区对日后研究aMCI患者的神经及血管的代偿机制提供了有效的影像学手段.     

动脉自旋标记MRI脑血流灌注成像在亚临床期肝性脑病患者的研究

目的 用动脉自旋标记(ASL)MRI灌注成像技术评价亚临床肝性脑病(SHE)患者基底节区的脑血流灌注模式.方法 对16例经神经心理试验诊断为SHE的患者和13例年龄和教育程度相匹配的健康志愿者进行MRI平扫和ASL灌注成像,分别测量双侧尾状核头、苍白球、壳核、丘脑和额叶白质的脑血流量(CBF),并以同侧额叶白质作为参照进行统计分析.结果 SHE患者各感兴趣区与白质的比值均高于对照组:CBF值右侧分别为0.88±0.17,1.01±0.06,0.96±0.13和0.93±0.10,左侧分别0.91±0.15,1.00±0.07,0.94±0.12和0.97±0.11,志愿者相应部位CBF值右侧分别为0.81±0.04,0.95±0.04,0.88±0.04和0.90±0.04,左侧分别为0.81±0.02,0.94±0.04,0.87±0.05和0.92±0.04.结论 ASL脑血流灌注成像探测到SHE患者基底节区的脑血流灌注是增加的.SHE患者基底节区灌注增加是血流从皮质到基底节区的重新分布.     

动脉自旋标记脑灌注技术在快速动眼睡眠障碍研究中的应用

目的:采用磁共振动脉自旋标记技术(ASL)对快速动眼睡眠障碍(R BD)患者的脑血流灌注异常情况进行研究,探讨ASL的应用价值。方法:我们的研究包括经同步视频多导睡眠监测(PSG)证实的原发性RBD患者20例及年龄、性别与RBD患者匹配的健康志愿者15例。所有的被试均在GE Discovery MR750磁共振扫描仪上进行ASL序列和3D-BRAVO序列的扫描。ASL的数据分析采用基于体素的方法在SPM8软件上进行。RBD组和对照组被试脑皮质灌注的差异采用双样本t检验进行分析。结果:RBD患者皮质灌注增高的区域主要位于额叶、前扣带皮质、辅助运动区、壳核、海马旁回、楔前叶和脑桥等;皮质灌注降低的区域主要位于枕叶、舌叶、颞叶中部等。结论:ASL技术可以发现RBD患者的灌注异常,在神经退行性病变的研究方便有较大的应用价值。     

抑郁症：应用MR动脉自旋标记法检测局部脑灌注变化

目的应用动脉自旋标记法（ASL）检测难治性抑郁症（RDD）、非难治性抑郁症（NDD）的局部脑灌注变化,并与健康对照组比较。方法本研究得到了当地伦理委员会批准,所有参加本研究的病人及志愿者均签署知情同意书。24例RDD、37例NDD以及42例健康对照者参加了本研究。从2006年2月-2007年7月．所有参与者均应用3TMR成像系统进行检查。对ASL和回波平面成像进行减影和平均以获得灌注加权像。采用基于体素的方法进行分析。感兴趣区放置在双侧海马、丘脑及豆状核。     

3D动脉自旋标记灌注成像联合3D磁敏感加权血管成像在急性脑梗死诊治中的应用价值

目的回顾性分析急性脑梗死磁共振3D动脉自旋标记灌注成像(3D ASL)与3D磁敏感加权血管成像(SWAN)的影像表现,并进一步评价其对溶栓治疗的指导价值。方法采用3.0T MRI扫描仪,63例急性脑梗死患者行常规MRI序列、DWI、MRA、3D ASL及SWAN检查。两名神经影像诊断专家分别独自评价DWI、MRA、3D ASL、SWAN影像表现。结果 52例(82.5%)患者ASL-CBF表现为血流灌注减低,其中38例(73.1%)患者ASL低灌注范围明显大于DWI;16例(30.8%)ASL低灌注患者SWAN像检测到大脑中动脉血栓。11例(17.5%)患者ASL显示明显高灌注。12例(75.0%)ASL低灌注患者和4例(25.0%)ASL高灌注患者,SWAN像显示梗死区内和/或边缘存在出血性低信号。结论3D ASL联合SWAN成像既能评价急性脑梗死患者的脑血流灌注特点、责任动脉内血栓,还能够评价患者潜在出血风险,对急性脑梗死患者溶栓治疗具有重要的指导价值。     

磁共振成像阴性的全面强直阵挛性癫痫发作间期SPECT研究

目的:研究MRI阴性的全面强直阵挛性发作癫痫(GTCS)患者在发作间期脑血流灌注特征.材料和方法:对60例MRI阴性的GTCS患者进行发作间期99mTc-ECD(双半胱乙脂)-SPECT脑血流灌注显像,10例年龄匹配的健康人作对照,计算感兴趣区(ROI)的不对称指数(%AI)并进行定量分析.将SPECT分析结果与患者的临床表现与EEG相比较.结果:60例MRI阴性的GTCS患者中29例表现为一侧丘脑、基底节区低灌注,其中4例为丘脑伴同侧颞叶低灌注,1例丘脑伴同侧颞叶及小脑低灌注,3例丘脑伴同侧枕叶低灌注,另有5例仅表现为一侧顶叶或颞叶低灌注,异常率为56.7%;而26例(43.3%)血流灌注无异常表现.脑血流灌注异常与正常的患者在性别、年龄、发病年龄、病程及EEG异常率方面无显著性差异(P＞0.05),而平均发作频率和总发作次数则具有显著性差异(P＜0.05).患者组和正常对照组在丘脑和基底节区的%AI存在显著性差异(P＜0.05).结论:①相当一部分MRI阴性GTCS患者存在发作间期脑血流灌注异常;②MRI阴性GTCS患者的脑血流异常灌注区主要分布在丘脑及基底节区而非皮质;③低灌注脑区可能是亚临床病灶或是癫痫反复发作所致的脑损伤区,这部分患者对药物治疗反应及预后不佳.     

动脉自旋标记与动态磁敏感对比增强技术在视神经脊髓炎中的对比研究

目的对比研究动脉自旋标记(ASL)和动态磁敏感对比增强灌注技术(DSC-PWI)在评价视神经脊髓炎(NMO)患者脑血流灌注中的作用。方法对经临床确诊的10例NMO患者行ASL及DSC-PWI检查,应用西门子后处理工作站软件获得14个感兴趣区(双侧对称的额叶、顶叶、颞叶、枕叶、尾状核、壳核和丘脑)的脑血流量(CBF)。应用配对t检验比较两种技术所得测量比值的差异,并用Pearson相关分析两种技术所得测量值的相关性。结果 ASL和DSC-PWI所测各感兴趣区的相对CBF比值均无显著性差异。(t=1.061,0.496,1.312,-0.342,-0.403,-0.156,0.224;P=0.329,0.637,0.238,0.744,0.708,0.881,0.830)除顶叶感兴趣区以外,两种方法所测其余各感兴趣区的CBF比值均呈显著相关性(r=0.659,P=0.000)。结论 ASL在评估NMO血流灌注方面与DSC之间有相似的敏感性,可用于临床评估视神经脊髓炎的脑血流灌注。     

CTP及ASL技术在脑梗死患者缺血半暗带评估中的应用价值

目的 探讨CT全脑灌注(CTP)、动脉自旋标记成像(ASL)技术在脑梗死患者缺血半暗带评估中的应用价值。方法 选取2019年1月～2020年12月我院脑梗死患者106例,所有患者均分别接受CTP及ASL检查,根据ASL及CTP检查情况分为A组、B组、C组。统计ASL及CTP检查情况、ASL及CTP检查所呈现病变面积、CTP检查病灶不同部位灌注参数(MTT、CBV、CBF)。结果 本组106例脑梗死患者经ASL和CTP检查,其中104例两种方法所显示灌注状态一致(均呈现为低灌注),其余2例两种检查方法结果不一致(CTP检查呈低灌注,ASL检查无异常); A组、B组、C组ASL及CTP检查所呈现的病变面积间差异无统计学意义(P 0. 05); CTP检查中心区域MTT大于边缘区域,而CBV、CBF小于边缘区域(P 0. 05)。结论 CTP和ASL技术在脑梗死患者缺血半暗带评估中具有一定应用价值,且在脑血流评估中具有较高一致性,临床可联合两种技术对脑梗死进行综合评估,保证诊断准确性,为临床制定针对性干预方案提供客观参考依据。     

动脉自旋标记技术在颅脑疾病中的初步研究

目的 评价动脉自旋标记(ASL)技术在颅脑疾病中的临床应用价值.方法 26例颅脑病变患者,其中急性脑梗死7例,短暂性脑缺血发作2例,神经元移行异常(多小脑回畸形)2例,胶质瘤9例,脑膜瘤4例,原始神经外胚层肿瘤1例,脑脓肿1例.除使用3.0T MR成像系统对所有患者行常规扫描及ASL序列(Q2TIPS)外,肿瘤及脑脓肿患者加做增强扫描,余患者(包括脑脓肿)加扫FLAIR、DWI序列(其中1例TIA患者行MRA检查),观察所得相对局部脑血流量(rCBF)图,分析双侧灌注变化.结果 ASL-rCBF图像上,缺血性脑血管病及神经元移行异常显示相应血供异常区域明显低灌注,脓肿及肿瘤显示与其血供基本相符的灌注情况.结论 ASL技术能快速非侵袭性地提供脑血流灌注信息,可用于缺血性脑血管病的早期诊断、神经元移行异常、肿瘤与脓肿病灶血供的初步评估及胶质瘤的分级.     

海马硬化所致颞叶癫痫SPECT与MRI脑血流灌注对照研究

目的通过应用单光子发射断层扫描(single-photon emission tomography,SPECT)脑血流灌注显像及动脉自旋标记(arterial spin labeling,ASL)脑血流灌注成像技术对海马硬化(hippocampal sclerosis,HS)所致颞叶癫痫(intractabletemporal lobe epilepsy,TLE)患者脑血流灌注,特别是海马区血流灌注进行定性及半定量测量,并比较其相关性。方法搜集经手术及病理证实为HS的18例TLE患者。选择性别、年龄匹配的21例健康志愿者作为对照组。18例患者及3例健康志愿者行SPECT脑血流灌注显像,全部患者及志愿者行ASL脑血流灌注成像。对HS所致TLE患者脑内,特别是海马区的血流灌注进行定性及定量分析,分别比较应用两种血流灌注方法(SPECT、ASL)测得的HS患者病变侧、对侧及与对照组海马区rCBF的差异。结果应用SPECT及ASL两种脑血流灌注显像技术测得HS所致TLE患者病变侧海马区rCBF均较对侧减低,病变侧与对侧海马区rCBF有显著性差异(P 0. 01);病变侧海马区rCBF较对照组明显减低,病变侧与对照组海马区rCBF有非常显著性差异(P 0. 01);对侧与对照组海马区rCBF有无显著性差异(P 0. 05)。结论SPECT脑血流灌注显像和ASL脑血流灌注成像技术定性分析HS所致TLE脑血流灌注改变一致性较好,均证实HS所致TLE病变侧海马区血流灌注减低。     

Changes in dorsolateral prefrontal connectivity after rTMS in treatment-resistant depression: a brain perfusion SPECT study

Purpose

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive and safe alternative to electroconvulsive therapy for treatment-resistant depression (TRD). After rTMS, changes in brain SPECT perfusion have been remotely identified within medial temporal limbic areas, while no local effects have been found within the left dorsolateral prefrontal cortex (DLPFC)—i.e. under the coil. Functional changes in connectivity may underlie these remote effects. Interestingly, functional connectivity has been recently investigated using perfusion SPECT, and abnormalities identified in TRD patients. The aim of the present study is to evaluate perfusion and connectivity SPECT changes in TRD patients after rTMS of the left DLPFC. We hypothesize that changes in DLPFC networks may explain remote hypoperfusions found after rTMS.

Methods

Fifty-eight TRD patients underwent a brain SPECT before and after high-frequency rTMS of the left DLPFC. Whole-brain voxel-based changes in perfusion were evaluated with SPM8, and inter-regional correlation analysis performed to study left DLPFC functional connectivity (p?<?0.005, corrected for cluster volume).

Results

After rTMS, patients were significantly improved on Beck Depression Inventory score (p?<?0.0001). Considering a 50% reduction threshold, 27 patients were identified as responders (47%). After rTMS, perfusion changes were not found locally within the left DLPFC, but remotely within the bilateral temporal lobes, including limbic areas. Inter-regional correlation SPECT analysis brings out a decrease of connectivity between the left DLPFC and both the cingulate/medial frontal cortex and bilateral medial temporal limbic areas, in relation with the clinical response.

Conclusions

rTMS of DLPFC in TRD patients leads to remote temporal hypoperfusions in relation with changes in functional connectivity between the DLPFC and the default mode network, especially including medial temporal limbic areas.

     

Statistical parametric mapping analysis of the relationship between regional cerebral blood flow and symptom clusters of the depressive mood in patients with pre-dialytic chronic kidney disease

OBJECTIVE: The aim of this study is to investigate the relationship between regional cerebral blood flow (rCBF) and symptom clusters of depressive mood in pre-dialytic chronic kidney disease (CKD). METHODS: Twenty-seven patients with stage 4-5 CKD were subjected to statistical parametric mapping analysis of brain single-photon emission computed tomography. Correlation analyses between separate symptom clusters of depressive mood and rCBF were done. RESULTS: The first factor (depressive mood) was negatively correlated with rCBF in the right insula, posterior cingulate gyrus, and left superior temporal gyrus, and positively correlated with rCBF in the left fusiform gyrus. The second factor (insomnia) was negatively correlated with rCBF in the right middle frontal gyrus, bilateral cingulate gyri, right insula, right putamen, and right inferior parietal lobule, and positively correlated with rCBF in left fusiform gyrus and bilateral cerebellar tonsils. The third factor (anxiety and psychomotor aspects) was negatively correlated with rCBF in the left inferior frontal gyrus, right superior frontal gyrus, right middle temporal gyrus, right superior temporal gyrus, and left superior frontal gyrus, and positively correlated with rCBF in the right ligual gyrus and right parahippocampal gyrus. CONCLUSIONS: In this study, the separate symptom clusters were correlated with specific rCBF patterns similar to those in major depressive disorder patients without CKD. However, some areas with discordant rCBF patterns were also noted when compared with major depressive disorder patients. Further larger scale investigations are needed.     

~(18)F-FDG PET显像对强迫症手术治疗前后的观察

目的　应用18F 脱氧葡萄糖 (FDG)PET显像评估强迫症手术治疗的疗效。方法　 9例经药物和心理治疗无效的难治性强迫症患者在术前和术后分别接受了YALE BROWN强迫症评定量表 (Y BOCS)、汉密尔顿焦虑量表 (HAMA)及FDGPET显像 ,同期的PET显像在治疗前后以相同的计数、脑定位及相同的处理条件进行采集和处理 ,患者在注射FDG时均保持相同的条件。与 10例年龄相匹配的对照者脑葡萄糖代谢进行比较 ,观察治疗前强迫症患者与对照者脑葡萄糖代谢的区别 ,并与手术治疗后的PET显像和量表评分进行比较。结果　与对照者相比 ,9例强迫症患者在额叶、扣带回、眶回、基底节尾状核头部和丘脑等处均可见FDG的高摄取。PET显像结果与YALE BROWN和HAMA量表评分结果相符。治疗后 9例患者中 6例取得良好疗效 ,其PET显像见额叶、扣带回、眶回、基底节尾状核头部和丘脑FDG代谢减低 ,且与量表评分结果一致。结论　FDGPET显像可用于解释强迫症的异常脑环路的存在 ,在治疗前有助于脑异常功能区域的定位 ,与YALE BROWN和HAMA的量表测定联合应用有助于强迫症的诊断。同时 ,FDGPET显像可用于该病的疗效观察和并发症的功能定位。     

Differences in 99mTc-HMPAO brain SPET perfusion imaging between Tourette's syndrome and chronic tic disorder in children

Early differential diagnosis between Tourette's syndrome and chronic tic disorder is difficult but important because both the outcome and the treatment of these two childhood-onset diseases are distinct. We assessed the sensitivity and specificity of brain single-photon emission tomography (SPET) perfusion imaging in distinguishing the two diseases, and characterized their different cerebral perfusion patterns. Twenty-seven children with Tourette's syndrome and 11 with chronic tic disorder (mean age 9.5 and 8.6 years, respectively) underwent brain SPET with technetium-99m hexamethylpropylene amine oxime (HMPAO). Visual interpretation and semi-quantitative analysis of SPET images were performed. On visual interpretation, 22 of 27 (82%) of the Tourette's syndrome group had lesions characterized by decreased perfusion. The left hemisphere was more frequently involved. None of the children with chronic tic disorder had a visible abnormality. Semi-quantitative analysis showed that, compared with children with chronic tic disorder, children with Tourette's syndrome had significantly lower perfusion in the left lateral temporal area and asymmetric perfusion in the dorsolateral frontal, lateral and medial temporal areas. In conclusion, using the visual approach, brain SPET perfusion imaging is sensitive and specific in differentiating Tourette's syndrome and chronic tic disorder. The perfusion difference between the two groups, demonstrated by semi-quantitative analysis, may be related more to the co-morbidity in Tourette's syndrome than to tics per se.     

Differences in 99mTc-HMPAO brain SPET perfusion imaging between Tourette's syndrome and chronic tic disorder in children

Early differential diagnosis between Tourette's syndrome and chronic tic disorder is difficult but important because both the outcome and the treatment of these two childhood-onset diseases are distinct. We assessed the sensitivity and specificity of brain single-photon emission tomography (SPET) perfusion imaging in distinguishing the two diseases, and characterized their different cerebral perfusion patterns. Twenty-seven children with Tourette's syndrome and 11 with chronic tic disorder (mean age 9.5 and 8.6 years, respectively) underwent brain SPET with technetium-99m hexamethylpropylene amine oxime (HMPAO). Visual interpretation and semiquantitative analysis of SPET images were performed. On visual interpretation, 22 of 27 (82%) of the Tourette's syndrome group had lesions characterized by decreased perfusion. The left hemisphere was more frequently involved. None of the children with chronic tic disorder had a visible abnormality. Semi-quantitative analysis showed that, compared with children with chronic tic disorder, children with Tourette's syndrome had significantly lower perfusion in the left lateral temporal area and asymmetric perfusion in the dorsolateral frontal, lateral and medial temporal areas. In conclusion, using the visual approach, brain SPET perfusion imaging is sensitive and specific in differentiating Tourette's syndrome and chronic tic disorder. The perfusion difference between the two groups, demonstrated by semi-quantitative analysis, may be related more to the co-morbidity in Tourette's syndrome than to tics per se.     

强迫症患者局部脑血流变化的SPM和ROI分析

目的 用^99Tc^m－双半胱乙酯（ECD）SPECT显像研究强迫症（OCD）患者的局部脑血流（rCBF)变化。方法 受检才为14例OCD患者（OCD组）和23例年龄相匹配的健康志愿者（CN组）。^99Tc^m-ECD脑SPECT显像后，用统计参数地图（SPM）和感兴趣区（ROI）两种方法分析OCD组和CN组的rCBF分布差别（rCBF增高区和降低区）。P值设为0.01。结果 SPM分析显示OCD患者双侧壳核、颞上回和楔前叶，右侧眶回、额上回和额中回，左侧颞枕叶、顶上小叶和小脑蚓部的rCBF降低；同时，左侧额下回和扣带回后部有小范围的rCBF升高。ROI分析显示OCD患者右侧大脑颞前叶、顶颞叶和左侧大脑颞枕叶的脑血流分数明显低于正常大脑的相应皮层（P＜0．01）。基底节的rCBF无明显差异。结论 研究结果支持OCD患者的额纹状体环路病变假说，SPM是分析rCBF变化的有力工具。     

Differences in resting state regional cerebral blood flow assessed with 99mTc-HMPAO SPECT and brain atlas matching between depressed patients with and without tinnitus

An increased occurrence of major depressive disorder has been reported in tinnitus patients, and of tinnitus in depressive patients. Involvement of several Brodmann areas (BAs) has been reported in tinnitus perception. The aim of this study was to assess the regional cerebral blood flow (rCBF) changes in depressed patients with and without tinnitus. The rCBF distribution at rest was compared among 45 patients with a lifetime prevalence of major depressive disorder, of whom 27 had severe tinnitus, and 26 normal healthy subjects. 99mTc-hexamethylenepropylene amine oxime (99mTc-HMPAO) single photon emission computed tomography (SPECT), using a three-headed gamma camera, was performed and the uptake in 34 functional sub-volumes of the brain bilaterally was assessed by a computerized brain atlas. Decreased rCBF in right frontal lobe BA 45 (P<0.05), the left parietal lobe BA 39 (P<0.00) and the left visual association cortex BA 18 (P<0.05) was found in tinnitus patients compared with non-tinnitus patients. The proportion of tinnitus patients with pronounced rCBF alterations in one or more of the temporal lobe BAs 41+21+22 was increased compared to gender matched controls (P<0.00) and patients without tinnitus (P<0.05). Positive correlations were found between trait anxiety scales from the Karolinska Scales of Personality and rCBF in tinnitus patients only in three limbic BAs (P<0.01), and inverse correlations in non-tinnitus patients only in five BAs subserving auditory perception and processing (P<0.05). rCBF differences between healthy controls and depressed patients with and without tinnitus were found in this study. The rCBF alterations were distributed in the cortex and were particularly specific in the auditory cortex. These findings suggest that taking audiological symptoms into account may yield more consistent results between rCBF studies of depression.     

Evaluation of dysthymic disorder with technetium-99 m hexamethylpropylene amine oxime brain single-photon emission tomography

Dysthymic disorder is a chronic disorder characterised by the presence of a depressed mood and is classified as a distinct category in DSM-IV, separately from major depression. Although brain imaging studies have been performed in major depressive disease, there have to date been no reports of such studies in dysthymic disorder. In this study 36 patients with dysthymic disorder were compared with 16 normal subjects using technetium-99m hexamethylpropylene amine oxime brain single-photon emission tomography. A relative blood flow ratio was calculated for each region of interest using the average tissue activity in the region divided by activity in the cerebellum. There were significant differences in the bilateral inferior frontal, bilateral parietal, right superior frontal and left posterior temporal regions in the patients with dysthymic disorder compared with the healthy controls. These findings support the hypothesis that the biological bases for dysthymic disorder and major depression are similar. Recognition of these regional abnormalities may have clinical utility in both the diagnosis and the treatment of dysthymic disorder. Further studies are needed to confirm our results and to assess the influence of treatment in patients with dysthymic disorder. Received 14 August and in revised form 24 October 1998     

Regional cerebral blood flow in the assessment of major depression and Alzheimer's disease in the early elderly

BACKGROUND: Alzheimer's disease and major depression are representative diseases that present forgetfulness and a depressive mood. It is often difficult to make a differential diagnosis between the two in the initial phase. AIM: To evaluate the differential diagnosis method using regional cerebral blood flow patterns with a three-dimensional stereotactic surface projection technique. METHODS: Twenty early-elderly patients with mild and moderate forgetfulness were studied. Among them, 10 were diagnosed as having major depression (the MD group) and the other 10 as having Alzheimer's disease (the AD group). All patients underwent cerebral perfusion single photon emission computed tomography (SPECT) with [(123)I]iodoamphetamine. A z-score was calculated for each pixel of the cerebral surface. Twenty-one circular regions of interest (ROIs) were placed on the z-score map. The significance of the statistical difference in ROI values between the two groups was determined by using the two-sided Mann-Whitney U-test. RESULTS: The z-scores for the lateral parietal, lateral temporal, bilateral precuneus and bilateral posterior cingulate gyrus were significantly reduced in the AD group compared with those in the MD group. The z-scores for the lateral frontal, left thalamus and bilateral medial frontal regions were significantly lower in the MD group than in the AD group. CONCLUSION: Our study demonstrated a difference in regional cerebral blood flow patterns between the early elderly with Alzheimer's disease and those with major depression. All patients were classified into the appropriate categories using discriminant analysis and z-scores of frontal and parietal regions. Brain perfusion SPECT was a useful tool for the differential diagnosis between Alzheimer's disease and major depression.     

Evaluation of dysthymic disorder with technetium-99 m hexamethylpropylene amine oxime brain single-photon emission tomography

Dysthymic disorder is a chronic disorder characterised by the presence of a depressed mood and is classified as a distinct category in DSM-IV, separately from major depression. Although brain imaging studies have been performed in major depressive disease, there have to date been no reports of such studies in dysthymic disorder. In this study 36 patients with dysthymic disorder were compared with 16 normal subjects using technetium-99m hexamethylpropylene amine oxime brain single-photon emission tomography. A relative blood flow ratio was calculated for each region of interest using the average tissue activity in the region divided by activity in the cerebellum. There were significant differences in the bilateral inferior frontal, bilateral parietal, right superior frontal and left posterior temporal regions in the patients with dysthymic disorder compared with the healthy controls. These findings support the hypothesis that the biological bases for dysthymic disorder and major depression are similar. Recognition of these regional abnormalities may have clinical utility in both the diagnosis and the treatment of dysthymic disorder. Further studies are needed to confirm our results and to assess the influence of treatment in patients with dysthymic disorder.