Myocardial perfusion imaging in patients with a recent, normal exercise test

AIM: To investigate the added value of myocardial perfusion scintigraphy imaging (MPI) in consecutive patients with suspected coronary artery disease (CAD) and a recent, normal exercise electrocardiography (ECG). METHODS: This study was a retrospective analysis of consecutive patients referred for MPI during a 2-year period from 2006-2007 at one clinic. All eligible patients were suspected of suffering from CAD, and had performed a satisfactory bicycle exercise test (i.e. , peak heart rate > 85% of the expected, age-predicted maximum) within 6 mo of referral, their exercise ECG was had no signs of ischemia, there was no exercise-limiting angina, and no cardiac events occurred between the exercise test and referral. The patients subsequently underwent a standard 2-d, stress-rest exercise MPI. Ischemia was defined based on visual scoring supported by quantitative segmental analysis (i.e. , sum of stress score > 3). The results of cardiac catheterizationwere analyzed, and clinical follow up was performed by review of electronic medical files. RESULTS: A total of 56 patients fulfilled the eligibility criteria. Most patients had a low or intermediate ATPⅢ pretest risk of CAD (6 patients had a high pre-test risk). The referral exercise test showed a mean Duke score of 5 (range: 2 to 11), which translated to a low postexercise risk in 66% and intermediate risk in 34%. A total of seven patients were reported with ischemia by MPI. Three of these patients had high ATPⅢ pre-test risk scores. Six of these seven patients underwent cardiac catheterization, which showed significant stenosis in one patient with a high pre-test risk of CAD, and indeterminate lesions in three patients (two of whom had high pre-test risk scores). With MPI as a gate keeper for catheterization, no significant, epicardial stenosis was observed in any of the 50 patients (0%, 95% confidence interval 0.0 to 7.1) with low to intermediate pre-test risk of CAD and a negative exercise test. No cardiac events occurred in any patients within a median follow up period of > 1200 d. CONCLUSION: The added diagnostic value of MPI in patients with low or intermediate risk of CAD and a recent, normal exercise test is marginal.

Predicting patient response to cardiac resynchronization therapy by gated SPECT myocardial perfusion imaging

Introduction Heart failure(HF)is widely prevalent(> 6 million cases)and rapidly growing(> 0.6 million new cases annually)in the United States.Although the prevalence of HF in China is less than that in the United States,the total number of HF patients in China exceeds 4 million.

Single photon emission CT perfusion imaging of cerebral blood flow of early syphilis patients

Objective To injvestigate the cerebral blood flow of patients with early syphilis Methods 99 Tc m ECD as brain perfusion imaging agent was used in single photon emission computed tomography (SPECT) for 32 patients with early syphilis and 15 controls Visual analyses were made on every BSPECT image Results The 32 patients with early syphilis had general, patchy hypoperfusion of cerebral blood flow Fourteen of the 32 patients had 48 episodes of marked patchy hypoperfusion of rCBF The responsible areas of hypoperfusion in a patchy distribution involved the left frontal lobe (6 episodes), right frontal lobe (3), left parietal lobe (7), right parietal lobe (6), left temporal lobe (11), right temporal lobe (5), left occipital lobe (3), left basal ganglia (3), cerebellum (1), and nerve nuceus (1) No abnormality was found in the control group Conclusions Cerebral blood flow abnormalities exist in patients with early syphilis General patchy hypoperfusion on SPECT imaging is common

Diffusion-weighted magnetic resonance imaging with short T1 inversion recovery-echo planar imaging combined with dual-head coincidence single photon emission computed tomography for diagnosing solitary pulmonary nodule

Positron emission tomography （PET） using 18F-fluorodeoxyglucose （FDG） has not been widely used in China for expensive cost （$1200）. Dual-head coincidence single photon emission computed tomography （DHC-SPECT） can depict many of the lesions depicted with a PET scanner in the lungs, which is used in place of PET-CT for discriminating malignant from benign pulmonary nodules in many studies. However, DHC-SPECT has inevitable false-negative results because the sensitivity for small lesions less than 2.0 cm is limited, and has high false-positive rate for active inflammatory nodules. Furthermore,DHC-SPECT also has a considerably higher cost （$300 in China） than other imaging examination.

Contrast Limited Adaptive Histogram Equalization for Qualitative Enhancement of Myocardial Perfusion Images

This paper establishes an efficient color space for the contrast enhancement of myocardial perfusion images. The effects of histogram equalization and contrast limited adaptive histogram equalization are investigated and the one which gives good enhancement results is extended to the suitable color space. The color space which gives better results is chosen experimentally. Uniqueness of this work is that contrast limited adaptive histogram equalization technique is applied to the chrominance channels of the cardiac nuclear image, leaving the luminance channel unaffected which results in an enhanced image output in color space.

Perioperative Evaluation of Cerebral Blood Flow Using ^123I-labeled N-isopropyl-p-iodoamphetamine Single-Photon Emission Computed Tomography without Blood Sampling in Patients Who Underwent Carotid Artery Stenting

The evaluation of regional cerebral vascular reserve （rCVR） with single-photon emission computed tomography （SPECT） is useful for predicting cerebral hyperperfusion following carotid artery stenting （CAS） and carotidendarterectomy （CEA）.

Repair of abnormal perfusion foci in idiopathic epilepsy patients under long-term antiepileptic treatment

Epileptic seizure control and the disappearance of epileptJform discharge are not indicative of the absence of abnormal perfusion foci. Perfusion abnormalities are a major cause of epileptic discharge, and the existence of abnormal perfusion loci implies possible relapse. Very little is known about perfusion abnormality repair in epilepsy. The present study selected 43 cases of idiopathic epilepsy under antiepileptic drug control for an average of 24 months. Comparisons between interictal single-photon emission CT （SPECT） images and long-term electroencephalogram （EEG） pre- and post-treatment showed that cases of normal SPECT increased by 48% （12/25） following treatment, with a total number of 15 reduced loci （,36%, 15/41 ）. Perfusion foci, Le., region of interest, were altered following treatment. These changes included： normal to abnormal in 3 cases （7%, 3/43; 2 hyperperfusion and 1 hypoperfusion）; abnormal to normal in 14 cases （32%, 14/43; 10 pre-treatment hypopeffusion and 4 hyperperfusion）; abnormal to abnormal in 7 cases （16%, 7/43; hyperperfusion to hypoperfusion in 5 cases, hypoperfusion to hyperpeffusion in 2 cases）. Long-term EEG revealed in an increase in the number of normal cases by 20 （40%, 20/39）, and there were 25 fewer cases with epileptiform discharges （66%, 25/38）. These findings demonstrate that long-term control of anti-epileptic drugs partially repaired cerebral perfusion abnormalities and reduced epileptiform discharges in idiopathic epilepsy.

Imaging-based diagnosis of acute renal allograft rejection

Kidney transplantation is the best available treatment for patients with end stage renal disease. Despite the introduction of effective immunosuppressant drugs, episodes of acute allograft rejection still endanger graft survival. Since efficient treatment of acute rejection is available, rapid diagnosis of this reversible graft injury is essential. For diagnosis of rejection, invasive core needle biopsy of the graft is the "gold-standard". However, biopsy carries the risk of significant graft injury and is not immediately feasible in patients taking anticoagulants. Therefore, a non-invasive tool assessing the whole organ for specific and fast detection of acute allograft rejection is desirable. We herein review current imaging-based state of the art approaches for non-invasive diagnostics of acute renal transplant rejection. We especially focus on new positron emission tomography-based as well as targeted ultrasoundbased methods.

Olfactory function in psychotic disorders: Insights from neuroimaging studies

Olfactory deficits on measures of identification, familiarity,and memory are consistently noted in patients with psychotic disorders relative to age-matched controls. Olfactory intensity ratings, however, appear to remain intact while the data on hedonics and detection threshold are inconsistent. Despite the behavioral abnormalities noted, no specific regional brain hypoactivity has been identified in psychosis patients, for any of the olfactory domains. However, an intriguing finding emerged from this review in that the amygdala and pirifom cortices were not noted to be abnormal in hedonic processing(nor was the amygdala identified abnormal in any study) in psychotic disorders. This finding is in contrast to the literature in healthy individuals, in that this brain region is strongly implicated in olfactory processing(particularly for unpleasant odorants). Secondary olfactory cortex(orbitofrontal cortices, thalamus, and insula) was abnormally activated in the studies examined, particularly for hedonic processing. Further research, using consistent methodology, is required for better understanding the neurobiology of olfactory deficits. The authors suggest taking age and sex differences into consideration and further contrasting olfactory subgroups(impaired vs intact) to better our understanding of the heterogeneity of psychotic disorders.

Novel contributions of multimodality imaging in hypertension:A narrative review

Hypertension is currently one of the most prevalent il nesses worldwide,and is the second most common cause of heart failure,only behind ischemic cardiomyopathy.The development of novel multimodality imaging techniques in recent years has broadened the diagnostic methods,risk stratification and monitoring of treatment of cardiovascular diseases available for clinicians.Cardiovascular magnetic resonance(CMR) has a great capacity to evaluate cardiac dimensions and ventricular function,is extremely useful in ruling-out ischemic cardiomyopathy,the evaluation of the vascular system,in making the differential diagnosis for resistant hypertension and risk stratification for hypertensive cardiomyopathy and constitutes today,the method of choice to evaluate left ventricular systolic function.Computed tomography(CT) is the method of choice for the evaluation of vascular anatomy,including coronary arteries,and is also able to provide both functional and structural information.Finally,nuclear cardiology studies have been traditionally used to evaluate myocardial ischemia,along with offering the capacity to evaluate ventricular,endothelial and cardiac innervation function;information that is key in directing the treatment of the patient.In this narrative review,the most recent contributions of multimodality imaging to the patient with hypertension(CMR,CT and nuclear cardiology) will be reviewed.

Novel SPECT Technologies and Approaches in Cardiac Imaging

Recent novel approaches in myocardial perfusion single photon emission CT(SPECT)have been facilitated by new dedicated high-effi ciency hardware with solid-state detectors and optimized collimators.New protocols include very low-dose(1 mSv)stress-only,two-position imaging to mitigate attenuation artifacts,and simultaneous dual-isotope imaging.Attenuation correction can be performed by specialized low-dose systems or by previously obtained CT coronary calcium scans.Hybrid protocols using CT angiography have been proposed.Image quality improvements have been demonstrated by novel reconstructions and motion correction.Fast SPECT acquisition facilitates dynamic fl ow and early function measurements.Image processing algorithms have become automated with virtually unsupervised extraction of quantitative imaging variables.This automation facilitates integration with clinical variables derived by machine learning to predict patient outcome or diagnosis.In this review,we describe new imaging protocols made possible by the new hardware developments.We also discuss several novel software approaches for the quantifi cation and interpretation of myocardial perfusion SPECT scans.

Nuclear medicine imaging in osteonecrosis of hip:Old and current concepts

Osteonecrosis(ON) is caused by inadequate blood supply leading to bone death, which results in the collapse of the architectural bony structure. Femoral head is the most common site involved in ON. Magnetic resonance imaging(MRI) is a commonly used imaging modality to detect early ON. When MRI is inconclusive, bone scan is helpful in detecting ON during early phase of the disease. As newer nuclear medicine equipment, like single photon emission computed tomography/computed tomography(CT) and positron emission tomography/CT, are emerging in medical science, we review the role of these imaging modalities in ON of femoral head.

Monitoring adenoviral based gene delivery in rat glioma by molecular imaging

AIM:To determine whether endothelial progenitor cells(EPCs)can be used as delivery vehicle for adenoviral vectors and imaging probes for gene therapy in glioblastoma.METHODS:To use cord blood derived EPCs as delivery vehicle for adenoviral vectors and imaging probes for glioma gene therapy,a rat model of human glioma was made by implanting U251 cells orthotopically.EPCs were transfected with an adenovirus(AD5/carrying hNIS gene)and labeled with iron oxide and inoculated them directly into the tumor 14 d following implantation of U251 cells.Magnetic resonance imaging(MRI)was used to in vivo track the migration of EPCs in the tumor.The expression of gene products was determined by in vivo Tc-99m single photon emission computed tomography(SPECT).The findings were validated with immunohistochemistry(IHC).RESULTS:EPCs were successfully transfected with the adenoviral vectors carrying hNIS which was proved by significantly(P<0.05)higher uptake of Tc-99m in transfected cells.Viability of EPCs following transfection and iron labeling was not altered.In vivo imaging showed the presence of iron positive cells and the expression of transgene(hNIS)product on MRI and SPECT,respectively,all over the tumors following administration of transfected and iron labeled EPCs in the tumors.IHC confirmed the distribution of EPC around the tumor away from the injection site and also showed transgene expression in the tumor.The results indicated the EPCs’ability to deliver adenoviral vectors into the glioma upon intratumor injection.CONCLUSION:EPCs can be used as vehicle to deliver adenoviral vector to glioma and also act as imaging probe at the same time.

Recent Advances in Noninvasive Cardiac Imaging

In the last several years,the rate of innovation in cardiac imaging techniques has accelerated signifi cantly.Advances have been seen in all 4 major modalities;echocardiography,nuclear(positron emission tomography(PET)and single photon emission computed tomography(SPECT),cardiac magnetic resonance imaging(CMR),and computed tomographic angiography(CTA).This issue of Cardiovascular Innovations and Applications will highlight many of these advances.

磷酸盐尿性间叶性肿瘤影像学表现

目的分析磷酸盐尿性间叶性肿瘤的多模态影像学表现。资料与方法回顾性收集2012年11月—2022年6月华中科技大学同济医学院附属同济医院经病理及分子影像证实的磷酸盐尿性间叶性肿瘤10例,分析4例CT、7例MRI及10例核医学影像特征和临床特点。结果10例患者主要临床症状:疼痛8例,无力4例,伴多发骨折9例。实验室检查:10例血磷降低,6例血25-羟维生素D降低,10例血碱性磷酸酶升高。CT平扫混杂密度4例,MRI平扫混杂信号6例,钙化多见,部分伴囊变及脂肪成分;增强后7例呈中度到明显不均匀强化。8例99Tcm-MDP SPECT全身骨显像示多发骨及关节摄取增高,8例18FFDG PET/CT示病灶代谢无增高或轻度增高,10例68Ga-DOTATATE PET/CT均表现为病灶部位明显高摄取。结论磷酸盐尿性间叶性肿瘤患者以疼痛、骨折及低磷血症为典型临床表现,影像学特征为病灶小且隐匿、成分复杂,68Ga-DOTATATE PET/CT显像对检出肿瘤高度敏感。

螺旋采集改善SPECT定量准确性及图像质量:体模研究

目的观察螺旋采集用于改善SPECT定量准确性及图像质量的价值。方法针对1个包含6个球体(直径分别为37、28、22、17、13和10 mm)的体模模型,分别向球体及体模腔内灌注640 kBq/ml及20 kBq/ml^(99)Tc^(m)O_(4)^(-)溶液,并以5、10及15秒/帧行螺旋采集与常规步进采集;比较2种采集方式所获图像质量主观评分及客观参数,包括本底变异系数(CV)、对比度噪声比(CNR)、平均放射性计数(C_(sphere))和测量定量误差百分比(Error%)的差异。结果各采集时间下,螺旋采集图像质量评分均高于常规步进采集,以5秒/帧时二者差值最大;螺旋采集的CV、CNR、C_(sphere)均优于常规步进采集(P均<0.05)。排除直径10、13 mm球体后,5、10秒/帧下,螺旋采集Error%均优于常规步进采集(P均<0.05),而15秒/帧下二者差异无统计学意义(P均>0.05)。结论相同采集时间、尤其较短采集时间下,以螺旋采集所获SPECT的定量准确性及图像质量优于常规步进采集。

影响心肌血流下降的因素及其价值研究

目的探讨传统单光子发射计算机断层成像(SPECT)获取的心肌灌注显像、半定量参数以及冠脉造影结果、临床参数对心肌缺血的影响。方法回顾性分析2022年6月至2022年10月在南京医科大学第一附属医院(江苏省人民医院)完成CZT-SPECT检查的116例临床疑似或确诊的冠心病患者临床资料,最终纳入39例患者。以三支主要冠脉区域心肌血流储备功能<2.1作为心肌缺血的诊断标准,绘制冠脉狭窄程度、区域负荷灌注积分(SS)、静息灌注积分(RS)和灌注积分差(DS)诊断心肌缺血的ROC曲线以获得最佳截断值和相应的诊断效能,通过逐步回归法建立预测模型,绘制ROC曲线。结果共计117支主要血管,其中判定为心肌缺血的有36支(30.77%)。冠脉狭窄程度、SS、RS和DS诊断心肌缺血的ROC曲线最佳截断值分别为53%、3.5、1.5、1.5,准确性分别为75.2%、74.4%、70.9%、72.6%,ROC曲线的AUC及95%CI分别为0.78(0.68~0.87)、0.64(0.53~0.74)、0.58(0.49~0.66)、0.65(0.55~0.75)。冠脉狭窄程度、血管区域心肌灌注显像、SS、RS和DS等单因素有意义的指标联合预测心肌缺血的ROC曲线的AUC及95%CI为0.79(0.69~0.88)。逐步回归法踢除变量后,最终模型预测心肌缺血的ROC曲线的AUC及95%CI为0.84(0.76~0.92)。结论SPECT心肌灌注显像中SS>3.5、DS>1.5、RS>1.5对预测心肌缺血有一定的意义,联合多个指标(冠脉造影结果、SS、DS、RS、心肌灌注显像)预测显著提高了对心肌缺血的诊断价值。

动态^(99m)Tc-sestamibi CZT-SPECT评价老年胸痛患者冠状动脉微血管功能障碍的临床特征

目的冠状动脉微血管功能障碍(coronary microvascular dysfunction,CMVD)常介导非内皮依赖性微血管的异常扩张,引起缺血和心绞痛。对于无心外膜冠状动脉狭窄的心血管疾病,微血管病变起着非常重要的作用,并与心血管事件的增加有关。冠状动脉血流储备(coronary flow reserve,CFR)是微血管水平检测冠状动脉硬化早期征象的最敏感参数之一。新型动态^(99m)Tc-sestamibi CZT-SPECT评估CFR已成为检测CMVD的一种很有希望的技术。我们旨在通过冠状动脉造影和动态CZT-SPECT描述胸痛患者CMVD的患病率、临床特征和预后。方法入选2020年1月至2022年1月因胸痛在华东医院住院的老年(年龄≥60岁患者298例)。他们均接受了冠状动脉造影和动态/常规状态下静息/负荷门控心肌灌注显像(myocardial perfusion imaging,MPI)。在血管水平上,如果任何冠状动脉狭窄<50%且CFR<2,则认为是CMVD。在患者层面,CMVD被认为是非阻塞性冠心病(coronary artery disease,CAD)的一种。我们还收集了病史、生化指标等信息。随访至2023年6月30日。主要不良心血管事件(major adverse cardiovascular event,MACE)定义为:因胸闷胸痛再住院、急性冠脉综合征和死亡。结果73.5%的患者有心绞痛但冠脉造影阴性。30.9%非阻塞性CAD患者有CMVD。非阻塞性CAD中,CFR<2组MACE发生率较CFR≥2组高(P<0.001)。在Logistic回归分析中,发现糖尿病(β1.837,OR 6.227,95%CI 3.07112.831,P<0.001)、冠状动脉慢血流(coronary slow flow,CSF)(β1.150,OR 3.157,95%CI 1.3417.434,P=0.009)和高脂血症(β0.832,OR 2.297,95%CI 1.0525.016,P=0.037)为CMVD的重要预测因子。结论在非阻塞性CAD患者中CMVD的MACE发生率高。糖尿病、高脂血症和CSF是CMVD的独立预测因子。采用动态^(99m)Tc-sestamibi CZT-SPECT定量CFR检测在技术上是可行的,可以反映冠状动脉微血管功能。

鼻咽癌颅底骨转移瘤SPECT/CT影像特征变化及诊断价值分析

目的分析单光子发射计算机体层成像CT(SPECT/CT)在诊断鼻咽癌(NPC)颅底骨转移瘤中的应用价值。方法选取2019年1月-2021年6月期间于我院拟接受手术治疗的60例NPC患者,全部患者术前均接受SPECT/CT及核磁共振成像(MRI)检查,以随访作为“金标准”,对比分析患者SPECT/CT、MRI检查影像特征以及SPECT/CT、MRI检查对NPC颅底骨转移的诊断结果和诊断效能。结果经SPECT/CT检查评估NPC的准确度、灵敏度、特异度、阳性预测值、阴性预测值分别为81.66%、86.04%、70.58%、88.09%、66.66%,经MRI检查准确度、灵敏度、特异度、阳性预测值、阴性预测值分别为63.33%、67.44%、52.94%、78.37%、39.13%(P<0.05);经SPECT/CT检查评估NPC颅底骨转移的准确度、灵敏度、特异度、阳性预测值、阴性预测值分别为76.66%、73.60%、81.81%、87.50%、64.28%,经MRI检查准确度、灵敏度、特异度、阳性预测值、阴性预测值分别为56.66%、50.00%、68.18%、73.07%、44.11%(P<0.05)。结论SPECT/CT在NPC颅底骨转移瘤中有较高的诊断价值,临床在放射治疗前参照SPECT/CT影像特征,可全面掌握病灶情况,提高诊断的准确率。

全身骨显像中肾脏显影异常的病因浅析

目的探讨全身骨显像中肾脏显影异常的发生情况并初步分析病因。方法回顾性分析2021年11月至2022年7月在我院行骨显像的患者1674例,对肾区不同类型的显影异常结合患者其他相关影像检查及临床资料进行定性评估。结果共发现肾脏显影异常147例(8.78%),其中肾实质显影明显54例(3.23%),肾脏集合系统(肾盏肾盂或输尿管)异常显影61例(3.64%),单肾不显影14例(0.84%),双肾不显影23例(1.37%),肾脏位置异常8例(0.48%)等异常,并对不同类型显影异常的可能病因进行了分析。结论骨显像中肾脏显影出现异常,可提示肾脏结构异常、尿路排泄障碍以及肾脏功能异常等情况,可引导临床按需要行进一步检查,以明确疾病的原因,对临床诊治具有一定的指导意义。