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.

A correlation of computed tomography perfusion and histopathology in tumor edges of hepatocellular carcinoma

BACKGROUND： The peripheral morphologic characteristics of hepatocellular carcinoma （HCC） reflect tumor growth patterns. Computed tomography （CT） perfusion is a new method to analyze hemodynamic changes in tissues. We assessed the relationship between CT perfusion and histopathologic findings in the periphery of HCC lesions. METHODS： Non-contrast CT, enhanced dual-phase CT, and CT perfusion were performed on 77 subjects （47 patients and 30 controls）. Based on the imaging findings of enhanced dual- phase CT, the tumor edges were classified into three types： type Ⅰ （sharp）; type Ⅱ （blurry）; and type Ⅲ （mixed）. The CT perfusion parameters included hepatic blood flow, hepatic arterial fraction, hepatic arterial perfusion, and hepatic portal perfusion. The tissue sections from resected specimens were subjected to routine hematoxylin and eosin staining and immunohistochemical staining for CD34. The correlations between microvessel density （MVD） and the CT perfusion parameters were analyzed using Pearson＇s product-moment correlation coefficient. Changes in the perfusion parameters in tumor edges of different tumor types were evaluated. RESULTS： Type Ⅰ （sharp）： the pathologic findings showed fibrous connective tissue capsules in the tumor edges, and an MVD 〈30/ram2. Type Ⅱ （blurry）： the histology showed that the edges were clear with no capsules and an MVD 〉30/ram2. Type Ⅲ （mixed）： the pathology was similar to that of types I and II, and an MVD 〉30/mm~. Hepatic blood flow, hepatic arterial fraction, hepatic arterial perfusion, and hepatic portal perfusion were significantly increased in the tumor edges of HCC patients compared to those of the controls （P〈0.05）. The correlation between CT perfusion parameters and MVD was higher in blurry tumor edges of type II than in those of types Ⅰ or Ⅲ. CONCLUSION： CT perfusion imaging of tumor edges may be helpful in revealing histopathological features, and indirectly reflect angiogenic changes of HCCs.

CT Perfusion Imaging Predicts One-Month Outcome in Patients with Acute Spontaneous Hypertensive Intracerebral Hemorrhage

Purpose: Little is known about the relationship between perihematomal perfusion parameters in acute spontaneous hypertensive intracerebral hemorrhage patients and recent outcome. The purpose of this study was to evaluate the relationship between the perfusion parameters of the perihematomal brain tissue and the recent prognosis of patients with acute spontaneous hypertensive intracerebral hemorrhage (shICH) using CT perfusion (CTP) imaging. Methods: Twenty-six patients with clinical and CT diagnosed supratentorial shICH received CTP scanning within 8 - 19 h after symptom onset. At the maximum levels of the hematoma, cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) of perihematomal area (isodense within 1cm rim of perilesion area on plain CT) and contralateral mirrored hemisphere were measured, and rCBF, rCBV, rMTT were calculated (ipsilateral/contralateral). The one-month follow-up in accordance with daily living table (Barthel index, BI) by telephone was recorded. Results: The CBV, CBF, and MTT values of perihematoma area were (1.61 ± 1.53) ml·100 g-1, (16.48 ± 12.58) ml·100 g-1·min-1, and (9.12 ± 2.57) s, respectively. (For more information,please refer to the PDF)

Differential Impact of Appropriate Use Criteria on the Association between Age and Abnormal Stress Myocardial Perfusion SPECT

Background:The diagnostic and prognostic value of appropriate use criteria(AUC)for coronary artery disease(CAD)is well established.Whether the diagnostic yield of AUC for predicting CAD is preserved among the elderly is not known.Methods:We analyzed a multisite prospective cohort of 1511 consecutive patients(age 59±13 years,57%males)who underwent outpatient,community-based single-photon emission computed tomography(SPECT)myocardial perfusion imaging(MPI).Appropriateness of the studies was determined on the basis of the 2013 multimodality AUC for detection and risk assessment of stable ischemic heart disease.Abnormal SPECT MPI was defi ned by either a summed stress score of 4 or greater or a summed difference score of 2 or greater.Results:Abnormal SPECT MPI was present in 190 patients(12.5%),while ischemia on MPI alone was present in 122 patients(8%).In multivariate logistic regression analysis,age of 60 years or greater,male sex,hypertension,diabetes mellitus,and known CAD were independent predictors of abnormal SPET MPI,while appropriate indication for testing was not.Age of 60 years or greater was also an independent predictor of inducible myocardial ischemia,while appropriate indication for testing was not.Among the elderly(≥60 years),regardless of appropriateness of testing,there was no difference in the prevalence of abnormal SPECT(19 vs.14%,P=0.14)or prevalence of SPECT ischemia(11 vs.11%,P=1.00).Among younger patients,however,appropriate testing predicted a greater prevalence of abnormal SPECT(12 vs.7%,P=0.013).Conclusion:In this multisite cohort,testing based on AUC did not discriminate the risk of abnormal SPECT MPI among the elderly.Caution is advised when relying on AUC for referral of elderly patients for SPECT MPI.

Perfusion CT findings in liver of patients with tumor during chemotherapy

AIM: To investigate the microcirculation changes in liver of patients with tumor during chemotherapy by perfusion computed tomography (CT). METHODS: Sixty patients with tumor and 20 controls were enrolled in this study. Perfusion CT parameters of patients and controls were compared, including hepatic perfusion index (HPI), mean transit time (MTT), and permeability-surface area product (PS). Correlation between perfusion CT parameters, treatment cycle and alanine aminotransferase (ALT) level was studied. RESULTS: No difference was found in HPI (25.68% ± 7.38% vs 26.82% ± 5.13%), MTT (19.67 ± 5.68 s vs21.70 ± 5.43 s) and PS (17.00 ± 4.56 mL/100 mL per min vs 19.92 ± 6.35 mL/100 mL per min) between pa- tients and controls. The HPI and MTT were significantly higher in patients undergoing 2 cycles of chemotherapy than in controls and those undergoing 1 cycle of che- motherapy (29.76% ± 5.87% vs 25.68% ± 7.38% and 25.35% ± 4.05%, and 25.61 ± 5.01 s vs 19.67 ± 5.68 s and 19.74 ± 4.54 s, respectively, P < 0.05). The HPI was higher in patients with hepatic steatosis than in controls and those without hepatic steatosis (30.85% ± 6.17% vs 25.68% ± 7.38% and 25.70% ± 4.24%, P < 0.05). Treatment cycle was well correlated with HPI and MTT (r = 0.40, r = 0.50, P < 0.01). ALT level was not correlated with perfusion CT parameters. CONCLUSION: HPI and MTT are significantly increased in patients with tumor during chemotherapy and well correlated with treatment cycle. Chemotherapy affects hepatic microcirculation in patients with tumor. Changes in hepatic microcirculation can be quantitatively assessed by perfusion CT.

Future of cardiac computed tomography

Coronary computed tomography angiography(CCTA)has become an integral tool in the noninvasive diagnostic workup of patients with suspected coronary artery disease in both elective and emergency settings. Today, it represents a mature technique providing accurate, non-invasive morphological assessment of the coronary arteries and atherosclerotic plaque burden. Iterative reconstruction algorithms, low kV imaging, and single-heart beat acquisitions hold promise to further reduce dose requirements and improve the safety and robustness of the technique in several circumstances including imaging of heavily calcified vessels, patients with morbid obesity or irregular heart rates, and assessment in the emergency setting. However, it has become clear over recent years that cardiac radiologists need to take further steps towards the development and integration of functional imaging with morphological CCTA assessment to truly provide a comprehensive evaluation of the heart. Computed tomography myocardial perfusion imaging, including both dynamic and static dual-energy approaches, has demonstrated the ability to directly assess and quantify myocardial ischemia with simultaneous CCTA acquisition with a reasonable contrast medium volume and radiation dose delivered to the patient. In order to promote CCTA in the clinical and research environments, radiologists should prepare to embrace the change from morphological to functional imaging, furnishing all the necessary resources and information to referring clinicians.

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.

Subtraction Perfusion CT: A Technical Note

It is challenging to attempt to obtain CT perfusion (CTP) images of the hyperdense tissues, which could conceal the density of contrast material during perfusion study. We report a new technique of subtraction CTP (SCTP) to compensate the shortcomings. SCTP post-processed by perfusion software for the data of post-perfusion images subtracting pre-perfusion corresponding images slice by slice in CTP source images is technically feasible without any adverse effects on patients. It provides a new functional imaging with quantitatively hemodynamic indexes of tissue microcirculation and reflects accurately the change of blood flow in tissues and organs.

“How many times must a man look up before he can really see the sky?” Rheumatic cardiovascular disease in the era of multimodality imaging

Cardiovascular involvement in rheumatic diseases(RD) is the result of various pathophysiologic mechanisms including inflammation, accelerated atherosclerosis, myocardial ischemia, due to micro- or macro-vascular lesions and fibrosis. Noninvasive cardiovascular imaging, including echocardiography, nuclear techniques, cardiovascular computed tomography and cardiovascular magnetic resonance, represents the main diagnostic tool for early, non-invasive diagnosis of heart disease in RD. However, in the era of multimodality imaging and financial crisis there is an imperative need for rational use of imaging techniques in order to obtain the maximum benefit at the lowest possible cost for the health insurance system. The oligo-asymptomatic cardiovascular presentation and the high cardiovascular mortality of RD necessitate a reliable and reproducible diagnostic approach to catch early cardiovascular involvement. Echocardiography remains the routine cornerstone of cardiovascular evaluation. However, a normal echocardiogram can not always exclude cardiac involvement and/or identify heart disease acuity and pathophysiology. Therefore, cardiovascular magnetic resonance is a necessary adjunct complementary to echocardiography, especially in new onset heart failure and when there are conflicting data from clinical, electrocardiographic and echocardiographic evaluation of RD patients.

多模态影像评估主动脉瓣置换术后左心室逆重构研究进展

慢性主动脉瓣狭窄及反流可导致左心室重构,这些变化在瓣膜置换术后是否可逆及可逆程度是影响外科手术时机和患者预后的主要决定因素。影像技术是目前常用于评估心肌结构与功能的无创性方法,其中超声心动图及增强CT有助于人工瓣功能评估和左心室形变监测,心脏磁共振及PET/CT有助于识别术后心纤维化的进展及消退,这些技术综合应用可早期诊断和无创检测术后左心室逆重构,从而改善临床结局。本文综述多模态影像学技术对主动脉瓣置换术后左心室逆重构评估及应用进展。

肥胖患者碲锌镉心脏专用不同采集体位心肌衰减伪影与性别关系的比较研究

目的:对比肥胖患者碲锌镉(cadmium-zinc-telluride,CZT)心脏专用单光子发射计算机断层显像不同采集体位心肌衰减伪影与性别的相互关系。方法:前瞻性收集了2024年1月至2024年3月肥胖患者(BMI≥28 kg/m^(2)),所有患者均于首都医科大学附属北京安贞医院核医学科进行了仰卧位、半直立位和直立位三个体位的门控负荷心肌灌注显像采集。使用美国心脏协会AHA 17节段5分法模型分析。衰减伪影定义为心肌灌注受损节段仅存在于一个或两个采集体位或在任意采集体位心肌节段灌注受损程度有所变化。采用Pearson卡方检验比较三个体位心肌衰减伪影的节段数量和总严重程度评分的差异。结果:共纳入73例肥胖患者,男性44例,女性29例。男性肥胖患者中,受累的左心室心肌衰减伪影节段总数量为10个,其中以下壁基底段数量和总严重程度评分最多,且在三个体位间比较差异有统计学意义。仰卧位、半直立和直立位采集时分别共有19、27和32例患者下壁基底段心肌无衰减伪影,准确率分别为43%(19/44)、61%(27/44)和73%(32/44)。女性肥胖患者中,受累的左心室心肌衰减伪影节段总数量为7个,其中下壁心尖段数量最多,且在三个体位间比较差异有统计学意义。仰卧位、半直立和直立位采集时分别共有21、16和11例患者下壁心尖段心肌无衰减伪影,准确率分别为72%(21/29)、55%(16/29)和38%(11/29)。结论:行CZT心脏专用单光子发射计算机心肌灌注断层显像时,男性肥胖患者优选直立位采集,以减少左心室下壁基底段心肌衰减伪影,女性肥胖患者优选仰卧位采集,以减少左心室下壁心尖段心肌衰减伪影。

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。

动态心电图和CT首过心肌灌注成像在冠心病心肌缺血诊断中的对比分析

目的评价动态心电图(DCG)和CT首过心肌灌注成像诊断冠心病心肌缺血的价值。方法选取2014年2月~2015年1月在开滦总医院疑诊冠心病患者55例,所有患者行DCG、冠状动脉CT成像(CCTA)、核素心肌灌注显像(MPI)检查。以MPI为参考标准,比较DCG、CT首过心肌灌注成像诊断心肌缺血的敏感性、特异性、阳性预测值、阴性预测值、准确性及其与MPI诊断结果的一致性。结果 55例患者完成检查。DCG诊断心肌缺血的敏感性69.70%(23/33),特异性72.73%(16/22),阳性预测值79.31%(23/29),阴性预测值61.54%(16/26),准确性70.91%(39/55),DCG与MPI结果的一致性Kappa=0.412(P<0.05);CT首过心肌灌注成像诊断心肌缺血的敏感性90.91%(30/33),特异性77.27%(17/22),阳性预测值85.71%(30/35),阴性预测值85.00%(17/20),准确性85.46%(47/55),CT首过心肌灌注成像与MPI结果的一致性Kappa=0.692(P<0.05)。结论 CT首过心肌灌注成像在诊断冠心病心肌缺血方面比DCG更有优势。

多层螺旋CT心肌灌注对缺血性心脏病的应用价值

目的探讨MSCT心肌灌注在缺血性心脏病(IHD)诊断与治疗中的应用价值。方法选取35例CAG和(或)支架植入术后IHD患者行MSCT心肌灌注扫描,分别测量并比较正常心肌与缺血心肌的CT值、血流量(BF)、血容量(BV)、峰值时间(MTP)、平均通过时间(MTT)及时间-密度曲线(TDC)。结果 35例患者MSCT心肌灌注扫描均可显示低灌注区,与CAG、SPECT及ECG提示心肌缺血区域相对应。首过灌注图像上缺血心肌CT值为(90.28±7.29)HU,正常心肌CT值为(141.05±9.54)HU;缺血心肌BF、BV减低,MTP、MTT延迟,与正常心肌的差异均具有统计学意义(P均<0.05)。34例正常心肌TDC呈稍快上升继而平缓下降;20例缺血心肌TDC呈缓慢上升,10例近乎水平,5例与正常心肌TDC形态相似。结论 MSCT心肌灌注成像可用于定位及诊断心肌缺血,在缺血性心脏病的诊断及治疗决策中起重要指导作用。

64层螺旋CT血管成像与心肌灌注显像探测功能相关冠状动脉病变

目的比较64层螺旋CT血管成像(CTA)和心肌灌注显像(MPI)对功能相关冠状动脉狭窄性病变的诊断价值。方法回顾性分析20例确诊和11例拟诊冠状动脉病变(CAD)患者的64层CTA和MPI图像。按照目测直径法判断CTA图像上冠状动脉狭窄程度:≥50%或<50%;相应MPI图像上的心肌缺血分为可逆性和固定性灌注异常区。结果31例患者的124条冠状动脉中,23条CTA图像上狭窄≥50%,其中7条(30.43%)狭窄血管的供血心肌在MPI上呈现灌注异常区;101条狭窄<50%及正常,其中10条(9.90%)血管的供血心肌在MPI图像上呈现灌注异常区。冠状动脉狭窄程度与其供应心肌节段发生缺血的风险概率之间差异有统计学意义(χ2=6.667,P=0.01),而冠状动脉不同狭窄部位与其供应心肌节段发生缺血的风险概率之间差异无统计学意义(χ2=6.839,P=0.065)。64层螺旋CTA在探测MPI图像上缺血心肌节段所对应的狭窄≥50%冠状动脉的敏感度、特异性、阴性预测值、阳性预测值分别为41.18%、85.05%、90.01%和30.43%。结论64层螺旋CTA能清晰显示冠状动脉的重要形态学信息,但其探测功能相关狭窄≥50%冠状动脉的阳性预测值较低,而MPI则是评价CAD导致心脏功能改变的重要检查方法。

CTCA结合CT首过心肌灌注成像诊断无症状性心肌缺血的价值探讨

目的探讨CTCA结合CT首过心肌灌注成像对无症状性心肌缺血(SMI)的诊断价值。方法 72例临床疑诊SMI患者行核素心肌灌注成像(MPI)及CTCA检查。以MPI为参考标准,比较CT首过心肌灌注成像、CTCA结合CT首过心肌灌注成像诊断SMI的敏感性、特异性、阳性预测值、阴性预测值、准确性及其与MPI诊断的一致性。结果 72例患者完成检查,以患者为观察对象,CT首过心肌灌注成像诊断SMI的敏感性90.91%(40/44),特异性71.43%(20/28),阳性预测值83.33%(40/48),阴性预测值83.33%(20/24),准确性83.33%(60/72),两种检查结果的一致性Kappa=0.640(P<0.05);CTCA结合CT首过心肌灌注成像诊断SMI的敏感性95.45%(42/44),特异性75.00%(21/28),阳性预测值85.71%(42/49),阴性预测值91.30%(21/23),准确性87.50%(63/72),两种检查结果的一致性Kappa=0.728(P<0.05);以病变血管为观察对象,CT首过心肌灌注成像诊断SMI的敏感性88.89%(48/54),特异性89.51%(145/162),阳性预测值73.85%(48/65),阴性预测值96.03%(145/151),准确性89.35%(193/216),两种检查结果的一致性Kappa=0.734(P<0.05);CTCA结合CT首过心肌灌注成像诊断SMI的敏感性92.59%(50/54),特异性90.74%(147/162),阳性预测值76.92%(50/65),阴性预测值97.35%(147/151),准确性91.20%(197/216),两种检查结果的一致性Kappa=0.780(P<0.05)。结论 CTCA结合CT首过心肌灌注成像诊断SMI有较高的准确性,作为"一站式"诊断冠心病在临床中有很好的应用前景。

CT冠状动脉造影结合心肌灌注显像检测血流受阻型冠状动脉病变

目的探讨CT冠状动脉造影(CTCA)结合腺苷负荷核素心肌灌注显像(MPS)无创地检测血流受阻型冠脉阻塞性病变的可行性与准确性。方法 105例怀疑或诊断为冠心病的患者,有创性冠状动脉造影检查前4周内完成CTCA与腺苷负荷MPS检查。以定量冠状动脉造影结合MPS的结果为参照,评价CTCA结合MPS诊断血流受阻型冠脉阻塞性病变的准确性及作为再血管化治疗"看门人"的可行性。结果对比定量冠状动脉造影结合MPS结果,CTCA结合MPS诊断血流受阻型冠脉阻塞性病变的敏感性、特异性、阳性预测值及阴性预测值均为100%。16%的再血管化治疗患者中并未发现血流受阻型冠脉阻塞性病变。结论对比定量冠状动脉造影结合MPS的结果,CTCA结合腺苷负荷MPS可以准确地检测血流受阻型的冠脉阻塞性病变,可以充当再血管化治疗的"看门人"。

X线衰减校正用于^(99m)Tc-N-NOET SPECT心肌灌注显像

目的评价X线衰减校正(AC)对99mTc-N-NOETSPECT心肌灌注显像(MPI)伪影鉴别的临床应用价值。方法对54例可疑冠心病(CAD)患者的102例次MPI(负荷49例次,延迟或静息53例次)进行X线AC,比较AC前后的图像。其中有14例行冠状动脉造影检查(CAG)。结果 54例受检者中,31例正常,12例心肌可逆性灌注缺损,11例固定性缺损;AC后40例正常,12例可逆性缺损,2例固定性缺损。102例次MPI中,AC前,下后壁显像剂分布减低22例次(22/102,21.57%),AC后为4例次(4/102,3.92%),差异有统计学意义(χ2=14.282,P<0.05);14例CAG受检者中,8例正常,6例冠状动脉狭窄≥50%。CAG正常者AC前MPI显示6例正常,2例下后壁固定性缺损;AC后8例均正常;6例CAD者AC前MPI显示2例正常,1例前壁近心尖部可逆性缺损、下后壁固定性缺损,3例可逆性缺损,AC后,2例正常者MPI无变化,前壁近心尖部可逆性缺损、下后壁固定性缺损者,下后壁恢复正常,前壁近心尖部仍呈可逆性缺损,3例可逆性缺损者无变化。结论 X线AC能有效鉴别99mTc-N-NOETSPECT心肌灌注图像中的下后壁伪影,但可引起新伪影出现于心尖和前壁。

能谱CT心肌灌注图像质量的优化

目的探讨能谱CT单能量成像与自适应统计迭代重建（adaptive statistical reconstruction,ASiR）心肌灌注的最佳扫描参数组合。方法对30例疑诊冠心病患者行心脏能谱扫描,对原始图像分别采用多组单能量联合不同权重ASiR技术以及传统混合能量模式重建并对特定心肌节段的噪声、信噪比（signal-to-noise ratio,SNR）、对比噪声比（contrast-to-noise ratio,CNR）及线束硬化伪影（beam-hardening artifacts,BHA）进行单因素方差分析。结果与传统混合能量成像相比,较高单能量可降低图像噪声和BHA,40%及以上ASiR重建可增强降噪效果,对伪影改善并不显著;75ke V对应的SNR（48%;P〈0.001;联合80%ASiR）和CNR（35%;P〈0.001;联合60%ASiR）有最大优化。结论与混合能量成像相比,70~75ke V单能量联合40%ASiR重建可显著降低心肌灌注图像噪声、改善伪影并提高SNR、CNR。