Evaluation of cerebral blood flow by single-photon emission computed tomography in young Asian Indians with hypertension

The objective of the study was to investigate abnormalities of regional cerebral blood flow (rCBF) in young (age 33.0+/-6.3 years; range 21-45 years) non-diabetic and normolipidemic Asian Indians with hypertension. The rCBF was assessed with single-photon emission computed tomography (SPECT) in patients with hypertension (n = 33) and healthy controls (n = 20). The SPECT findings were normal in 41 subjects and showed abnormalities of cerebral perfusion in 10 subjects, all of which were hypertensive patients. These observations are extremely important for a vast number of young hypertensive patients in India. To prevent cerebrovascular accidents in future, patients with hypertension and decreased rCBF should be carefully monitored and their hypertension should be strictly controlled. These subjects may also be researched as potential candidates for preventive antiplatelet therapy.     

磁共振心肌灌注延迟增强与核素心肌灌注/代谢显像识别存活心肌对比研究

目的应用磁共振成像心肌灌注延迟显像(DE-MRI)所显示的高信号识别存活心肌和瘢痕组织,通过与99Tcm-甲氧基异丁基异腈(MIBI)单光子发射型计算机断层(SPECT)和18F-脱氧葡萄糖(FDG)SPECT进行对比研究,评估其诊断的敏感性和特异性,并分析两种方法的一致性。方法34例临床确诊的心肌梗死患者,拟行再血管化手术治疗。男性29例,女性5例,年龄(58.0±9.8)岁,接受心脏MRI及SPECT灌注/代谢显像检查。两种方法各划分5个等级,依据17节段分析法,分析34例患者共578个节段,并对两种评价心肌存活的方法行一致性分析。结果DE-MRI判断存活心肌431段(74.6%),坏死心肌147段(25.4%)。SPECT灌注/代谢显像诊断正常心肌336段(58.1%),坏死心肌212段(36.7%),缺血心肌30段(5.2%)。两种方法半定量分析显示一致性较好,Kappa值为0.51(>0.4)。以节段为单位,DE-MRI的敏感性为61.3%,特异性为95.4%。结论DE-MRI能够有效地识别存活心肌和瘢痕组织,并与18F-FDGSPECT一致性较好。     

核素心肌灌注显像与电子束CT诊断冠心病的对比研究

目的 :比较核素心肌灌注显像 (SPECT)与电子束 CT(EBCT)冠状动脉钙化定量积分对冠心病 (CHD)的诊断价值。方法 :44例住院患者同时进行冠状动脉造影 (CAG)、SPECT和EBCT检查。以 CAG为金标准 ,比较 SPECT与 EBCT诊断 CHD的各项诊断指标 ,并评价平行试验和系列试验的诊断指标。结果 :SPECT诊断 CHD的敏感性为 88.9% ,特异性为 69.2 % ,准确性为 77.3% ;EBCT以钙化积分≥ 1 0分为阳性标准 ,敏感性、特异性、准确性分别为 77.8%、80 .8%及 79.5%。这两种方法对检测 CHD的价值相似 (P >0 .0 5)。 SPECT与 EBCT联合平行试验的准确性为 72 .7% ;系列试验的准确性为 86.4%。结论 :SPECT与 EBCT诊断 CHD的效率相近 ;SPECT显像和 EBCT冠状动脉钙化定量积分法均为非创伤性检查法 ,对 CHD的诊断各有优势 ,宜结合使用     

Cerebral imaging by magnetic resonance imaging and single photon emission computed tomography in systemic lupus erythematosus with central nervous system involvement

OBJECTIVE: To assess the significance of magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) abnormalities in patients with systemic lupus erythematosus (SLE). METHODS: Forty-four patients with SLE were retrospectively analysed. Patients were classified into three groups [1 and 2: patients with central nervous system (CNS) manifestations before and after starting high-dose steroid therapy, respectively; 3: patients without CNS manifestations. MRI was performed in all 44 patients and SPECT in 31. RESULTS: Abnormal findings in MRI were found in 19 patients. MRI abnormalities were significantly more frequent in patients with CNS manifestations than in those without [71 vs 17%, odds ratio (OR) 11.9, confidence interval (CI) 2.8-49.9, P=0.0003]. After the initiation of steroid therapy, patients with CNS manifestations also had an increased frequency of abnormal MRI. No correlation was found between SPECT findings and CNS manifestations. However, patients with CNS manifestations after starting steroids showed a markedly increased frequency of abnormal MRI and SPECT compared with those without CNS manifestations (80 vs 7%; OR 56, CI 4.4-719, P=0.0003). The positive predictive value of abnormality in both techniques in developing CNS manifestations after starting steroids was 89%. CONCLUSION: MRI findings correlated with CNS manifestations in SLE. Where there is a high suspicion of CNS involvement, the combination of MRI and SPECT may be useful in predicting CNS manifestations after starting steroid therapy.     

Myocardial infarct quantification in the dog by single photon emission computed tomography

Radionuclide techniques for sizing acute myocardial infarction have been hampered by the intrinsic limitations of the scintillation camera. Emission computed tomography can overcome these limitations. Single photon emission computed tomograms of the distribution of technetium-99m pyrophosphate in acute anterior and posterior infarcts were obtained in 16 dogs after death. Tomograms were also obtained in 10 dogs during life without gating. The size of the infarcts was determined by staining gross sections of the heart with nitro blue tetrazolium, dissecting out the infarcted tissue and weighing it. Infarct sizes were determined from the tomographic images and compared with the measured infarct sizes. Good images showing the location and three-dimensional extent of the infarcts were obtained in all dogs. The measured and calculated infarct sizes correlated well (r = 0.85). Comparison of the calculated sizes in the living (non-gated) and dead ("physiologically" gated) animals showed reasonable agreement (r = 0.87). Single photon emission computed tomography is a feasible and useful technique for localizing and sizing acute myocardial infarctions.     

Single photon emission computed tomography and magnetic resonance imaging evaluation in SLE patients with and without neuropsychiatric involvement

Objective. To assess the relationship between clinical pictureand neuroimaging in patients affected by SLE with and withoutneuropsychiatric (NP) involvement. Methods. One hundred and seven SLE patients including 66 withNP involvement (NPSLE) with focal or diffuse presentation and41 without underwent single photon emission computed tomography(SPECT) and MRI. Results. After stratification for diffuse or focal NP involvement,in the 52 patients with diffuse presentation, abnormalitiesdetected with MRI or SPECT did not differ from patients withoutNP; however, after combining the two techniques, a normal resultwas more frequently observed in patients without NP involvement(P = 0.010). In the 14 patients with focal presentation, MRIalone and concordant abnormal MRI plus SPECT were more frequentlydetected in the NPSLE group; again normal findings by both techniquessimultaneously applied were more frequently found in SLE patientswithout NP involvement. White matter hyperintense T2-weightedlesions were the most frequent MRI abnormal findings in bothgroups, but the presence of multiple lesions (>5) involvingboth the hemispheres at subtentorial level was limited to NPSLEpatients. Multifocal hypoperfused SPECT areas were more frequentlyobserved in frontal and parietal lobes of NPSLE. Conclusions. Combining SPECT and MRI appears more useful thanthe two techniques alone and may help the clinician in the assessmentof patients with NP involvement since normal findings contemporarilydetected by these two techniques have been rarely observed inpatients with NP involvement especially in those with focalmanifestations where MRI and SPECT were never simultaneouslynormal. KEY WORDS: Systemic lupus erythematosus, Central nervous system, Magnetic resonance imaging, Single photon emission computed tomography Submitted 29 June 2007; revised version accepted 3 December 2007.     

N-isopropyl-p- 123I iodoamphetamine single photon emission computed tomography study of Parkinson's disease with dementia

BACKGROUND: Intellectual deterioration occurs in 10-40% of patients with Parkinson's disease. However, there are many conflicting studies on its relation with brain perfusion and the nature of this dementing process remains controversial. OBJECTIVE: To compare cortical perfusion by SPECT using (123)I-IMP between Parkinson's disease patients with dementia and those without dementia and to investigate the correlation between dementia in Parkinson's disease and brain perfusion in various areas. METHODS: Fifty-two cases of Parkinson's disease and 10 control cases were studied. The Parkinson's disease with dementia group included 30 cases and the Parkinson's disease without dementia group included 22 cases. RESULTS: By multiple logistic regression method, we demonstrated significant hypoperfusion in the occipital cortex in Parkinson's disease with dementia. CONCLUSIONS: The cause of dementia in Parkinson's disease may vary. We demonstrated that occipital hypoperfusion was closely correlated to dementia in Parkinson's disease compared to frontal, parietal and temporal perfusion.     

Relation of left ventricular hypertrophy to regional cerebral blood flow: single photon emission computed tomography abnormalities in essential hypertension

Several reports have shown that left ventricular hypertrophy (LVH) is an independent predictor of acute cerebrovascular events. The aim of the present study was to investigate the relationship between LVH and cerebral blood flow in middle-aged patients with essential hypertension. Forty never-treated hypertensive patients (24 men, 16 women, aged 50-60 years) without clinical evidence of target organ damage were studied. Regional cerebral blood flow was measured by means of single photon emission computed tomography of the brain. Twenty-nine patients showed echocardiographic criteria of LVH; 11 patients did not show this feature. No differences were found in regional cerebral blood flow ratio of all brain areas studied between hypertensives with or without LVH except for the striatum area. The regional cerebral blood flow ratio was significantly reduced in the striatum region of hypertensive patients with LVH, compared with patients without LVH (91.5+/-7.4 vs 98.1+/-8.3; P=.023). This relationship remained significant after adjusting for blood pressure. The authors conclude that the presence of LVH in middle-aged patients with essential hypertension is associated with a reduction of regional cerebral blood flow in the striatum area.     

Detection of cervical lymph node metastases in nasopharyngeal carcinomas: comparison between technetium-99m methoxyisobutylisonitrile single photon emission computed tomography and magnetic resonance imaging

We compared the effectiveness technetium-99m methoxyisobutylisonitrile (Tc-99m MIBI) single photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) of head and neck in evaluating cervical lymph node (LN) metastasis in nasopharyngeal carcinomas (NPC). Forty NPC patients with cervical LN metastases confirmed histopathologically underwent Te-99m MIBI SPECT and MRI of the head and neck to evaluate cervical LN metastases. For 16 LN lesions with discordant results between Tc-99m MIBI SPECT and MRI, Tc-99m MIBI SPECT could correctly detect 1 metastatic and 10 benign LN lesions as well as MRI could correctly detect 3 metastatic and 2 benign LN lesions. Agreement positive results of Tc-99m MIBI SPECT and MRI could correctly detect all of the remaining 24 metastatic LN lesions. Tc-99m MIBI SPECT has a better specificity but a lower sensitivity for detecting cervical LN metastases in NPC when compared with MRI. The combined use of Tc-99m MIBI SPECT and MRI could increase the accuracy compared with the single use of either Te-99m MIBI SPECT or MRI to detect cervical LN metastases in NPC.     

Myocardial perfusion imaging with positron emission tomography and single photon emission computed tomography: frequency and causes of disparate results

The purpose of this study was to compare rubidium-82 PET withthallium-201 SPECT imaging in 150 patients. Both techniquesfollowed a single dipyridamole-handgrip stress, and images weredisplayed using the same 3-dimensional format and quantitativecolour scale. Coronary arteriography was employed to assignthe correct diagnosis in situations of disparity. Results of PET and SPECT were at least partially concordantin 110 patients (73%), although 22 had more than one defect.A reversible perfusion defect was identified in 60 patients,but the scans were concordant in only 20 (33%). These disparitieswere chiefly due to false-negative SPECT imaging (22 patients,55%), and probable delayed thallium redistri bution (13 patients,33%). No patients had ischaemia correctly identified by SPECTin the presence of normal PET imaging. Persistent defects wereidentified in 91 patients, some of whom also had reversibledefects, and the results were consistent in 54 (59%). Otherthan the delayed thallium redistribution group, the major categoriescausing disparities were false-positive (6 patients, 16%), andfalse negative SPECT (8 patients, 22%), attributable to attenuationand scatter. PET appears able to identify smaller, less ischaemic areas subtendedby milder coronary stenoses. The availability of a true restingscan with Rb-PET enhances the discrimination between ischaemiaand infarction. Attenuation correction, and the high energyphotons of positron annihilation, yield more accurate evaluationof inferior wall defects and greater specificity in the presenceof soft tissue attenuation.     

Location of myocardium at risk in patients with first-time ST-elevation infarction: comparison among single photon emission computed tomography, magnetic resonance imaging, and electrocardiography

Background

The amount of myocardium at risk (MaR) during acute coronary occlusion and the duration of occlusion are important determinants of final infarct size. The main goal of early reperfusion therapy is to salvage ischemic myocardium, thereby preserving left ventricular function. The aims of the present study were to test the feasibility of developing polar plot representations of MaR, for perfusion single photon emission computed tomography (SPECT), regional wall thickening by magnetic resonance imaging (MRI), and distribution of ST-segment changes. A second aim was to test the hypothesis that these different modalities display similar localization of the MaR in patients with reperfused first-time myocardial infarction.

Methods

Eleven patients with first-time myocardial infarction with ST-elevation received ^99mTc tetrofosmin before primary percutaneous coronary intervention, SPECT imaging within 3 hours, and cardiac MRI of the left ventricle within 24 hours. The results for SPECT, MRI, and electrocardiogram (ECG) were developed into polar plots, and two expert observers designated the culprit coronary artery as assessed by angiography.

Results

The perfusion SPECT, MRI wall thickening, and ST changes are presented in side-by-side polar plots. In total, the culprit artery, based on the location of the MaR, was correctly designated in 91%, 82%, and 91% of cases by SPECT, MRI, and ECG, respectively.

Conclusions

Polar representation for localization of the MaR by SPECT perfusion, MRI wall thickening, and ECG ST-segment deviation is feasible. All 3 modalities have the potential to be used for indirect visual designation of the culprit artery in patients with first-time acute coronary occlusion.     

Legionnaires' disease with hypoperfusion in the cerebellum and frontal lobe on single photon emission computed tomography

A 59-year-old man was admitted for further investigation of headache. Neurological examination revealed memory loss, disorientation, and bilateral intention tremor. Legionella pneumophila antigen was detected in the urine. Brain magnetic resonance diffusion-weighted images showed marked hyperintensity in the splenium of the corpus callosum without other abnormalities. Single photon emission CT with Tc-99m hexamethyl-propyleneamine oxime showed multi-focal hypoperfusion in the brain, involving mainly the cerebellum and frontal lobe. This is the first report demonstrating cerebellar and frontal lobe hypoperfusion without corresponding MRI abnormalities in a patient with central nervous system Legionnaires' disease.