Prognostic value of vasodilator response using rubidium-82 positron emission tomography myocardial perfusion imaging in patients with coronary artery disease

Background

Prognostic value of positron emission tomography (PET) myocardial perfusion imaging (MPI) is well established. There is paucity of data on how the prognostic value of PET relates to the hemodynamic response to vasodilator stress. We hypothesize that inadequate hemodynamic response will affect the prognostic value of PET MPI.

Methods and results

Using a multicenter rubidium (Rb)-82 PET registry, 3406 patients who underwent a clinically indicated rest/stress PET MPI with a vasodilator agent were analyzed. Patients were categorized as, “responders” [increase in heart rate?≥?10 beats per minute (bpm) and decrease in systolic blood pressure (SBP) ≥10 mmHg], “partial responders” (either a change in HR or SBP), and “non-responders” (no change in HR or SBP). Primary outcome was all-cause death (ACD), and secondary outcome was cardiac death (CD). Ischemic burden was measured using summed stress score (SSS) and % left ventricular (LV) ischemia. After a median follow-up of 1.68 years (interquartile range?=?1.17- 2.55), there were 7.9% (n?=?270) ACD and 2.6% (n?=?54) CD. Responders with a normal PET MPI had an annualized event rate (AER) of 1.22% (SSS of 0–3) and 1.58% (% LV ischemia?=?0). Partial and non-responders had higher AER with worsening levels of ischemic burden. In the presence of severe SSS ≥12 and LV ischemia of ≥10%, partial responders had an AER of 10.79% and 10.36%, compared to non-responders with an AER of 19.4% and 12.43%, respectively. Patient classification was improved when SSS was added to a model containing clinical variables (NRI: 42%, p?<?0.001) and responder category was added (NRI: 61%,

Conclusion

Hemodynamic response during a vasodilator Rb-82 PET MPI is predictive of ACD. Partial and non-responders may require additional risk stratification leading to altered patient management.

     

Measurement of cardiac output with first-pass determination during rubidium-82 PET myocardial perfusion imaging

In addition to providing useful clinical information, cardiac output determined during rubidium-82 positron emission tomography (PET) myocardial perfusion studies can be used in the measurement of absolute regional myocardial blood flow using Sapirstein's method. This investigation was conducted to compare cardiac output values obtained by post-processing data acquired in a list mode PET myocardial perfusion study with those obtained using a technetium-99m-labeled red blood cell method on the same patients. Results from 14 patients showed that cardiac output can be accurately measured simultaneously in a⁸²Rb PET myocardial study, allowing determination of multiple perfusion and functional parameters of the heart, thus improving the cost-effectiveness of the⁸²Rb PET study.     

A prospective comparison of rubidium-82 PET and thallium-201 SPECT myocardial perfusion imaging utilizing a single dipyridamole stress in the diagnosis of coronary artery disease

The purpose of the present study is to prospectively compare myocardial perfusion imaging with rubidium-82 (82Rb) by positron emission tomography (PET) with thallium-201 (201Tl) imaging by single-photon emission tomography (SPECT) by recording both studies with a single dipyridamole handgrip stress, and reading both sets of images with the same display technique. In a series of 202 patients with previous coronary arteriography, the sensitivity, specificity, and accuracy of 82Rb PET were 93%, 78%, and 90% and for 201Tl SPECT 76%, 80%, and 77%, respectively. When 70 patients with previous therapeutic interventions were excluded, the remaining 132 patients showed a sensitivity, specificity, and accuracy of 95%, 82% and 92% for 82Rb PET and 79%, 76%, and 78% for 201Tl SPECT. The improved contrast resolution of PET resulted in markedly superior images and a more confident identification of defects.     

Short-term repeatability of resting myocardial blood flow measurements using rubidium-82 PET imaging

Background

Rubidium-82 (⁸²Rb) PET imaging has been proposed for routine myocardial blood flow (MBF) quantification. However, few studies have investigated the test-retest repeatability of this method. The aim of this study was to optimize same-day repeatability of rest MBF imaging with a highly automated analysis program (FlowQuant) using image-derived input functions and dual spillover corrections (SOC).

Methods

Test-retest repeatability of resting left-ventricle (LV) MBF was measured in patients (n?=?27) with suspected coronary artery disease (CAD) and healthy volunteers (n?=?9). The effects of scan-time, reconstruction, and quantification methods were assessed with correlation and Bland-Altman repeatability coefficients.

Results

Factors affecting rest MBF included gender, suspected CAD, and SOC (P?<?.001). Significant test-retest correlations were found using all analysis methods tested (r?>?0.79). The best repeatability coefficient for same-day MBF was 0.20?mL/minute/g using a 6-minute scan-time, iterative reconstruction, SOC, resting rate-pressure-product (RPP) adjustment, and left atrium input function. This protocol was significantly less variable than standard protocols using filtered back-projection reconstruction, longer scan-time, no SOC, or LV input function.

Conclusion

Absolute MBF can be measured with good repeatability using FlowQuant analysis of ⁸²Rb PET scans with a 6-minute scan time, iterative reconstruction, dual SOC, RPP-adjustment, and an image-derived input function in the left atrium cavity.     

Manufacture of strontium-82/rubidium-82 generators and quality control of rubidium-82 chloride for myocardial perfusion imaging in patients using positron emission tomography

We describe a protocol to manufacture ⁸²Sr/⁸²Rb generators and ⁸²RbCl for myocardial imaging with PET. The generators are manufactured in 3 stages: (1) preparation of a tin oxide column, (2) leak test of the generator column and (3) loading of the generator with ⁸²Sr. The generators produced sterile and non-pyrogenic ⁸²RbCl for i.v. injection. No significant ⁸²Sr/⁸⁵Sr breakthroughs were observed after elution with 20 l of saline. The automated system delivered human doses of ⁸²RbCl accurately.     

Quantification of myocardial perfusion using cardiac magnetic resonance imaging correlates significantly to rubidium-82 positron emission tomography in patients with severe coronary artery disease: A preliminary study

Introduction

Aim was to compare absolute myocardial perfusion using cardiac magnetic resonance imaging (CMRI) based on Tikhonov's procedure of deconvolution and rubidium-82 positron emission tomography (Rb-82 PET).

Materials and methods

Fourteen patients with coronary artery stenosis underwent rest and adenosine stress imaging by 1.5-Tesla MR Scanner and a mCT/PET 64-slice Scanner. CMRI were analyzed based on Tikhonov's procedure of deconvolution without specifying an explicit compartment model using our own software. PET images were analyzed using standard clinical software. CMRI and PET data was compared with Spearman's rho and Bland–Altman analysis.

Results

CMRI results were strongly and significantly correlated with PET results for the absolute global myocardial perfusion differences (r = 0.805, p = 0.001) and for global myocardial perfusion reserve (MPR) (r = 0.886, p < 0.001). At vessel territorial level, CMRI results were also significantly correlated with absolute PET myocardial perfusion differences (r = 0.737, p < 0.001) and MPR (r = 0.818, p < 0.001). Each vessel territory had similar strong correlation for absolute myocardial perfusion differences (right coronary artery (RCA): r = 0.787, p = 0.001; left anterior descending artery (LAD): r = 0.796, p = 0.001; left circumflex artery (LCX): r = 0.880, p < 0.001) and for MPR (RCA: r = 0.895, p < 0.001; LAD: r = 0.886, p < 0.001; LCX: r = 0.886, p < 0.001).

Conclusion

On a global and vessel territorial basis, CMRI-measured absolute myocardial perfusion differences and MPR were strongly and significantly correlated with the Rb-82 PET findings.     

腺苷负荷13N-NH3 PET心肌灌注显像结合冠状动脉CTA诊断冠心病

目的 评价腺苷负荷13N-NH3PET心肌灌注显像(MPI)与CT冠状动脉造影(CTA)相结合对提高冠心病(CAD)诊断准确性的临床应用价值.方法 对25例怀疑CAD的患者同时行腺苷负荷13N-NH3MPI及CTA,1个月内行导管法冠状动脉造影(CAG).结果 (1)25例患者共300个冠状动脉节段,CTA显示良好节段为263个,显示率(显示良好节段所占百分比)达87.7%.(2)25例患者CTA、MPI及CTA+MPI诊断CAD的灵敏度、特异性、准确性、阳性预测值及阴性预测值分别为82.1%(23/28),87.5%(14/16)及93.8%(15/16);93.2%(219/235),8/9及9/9;92.O%(242/263),88.0%(22/25)及96.0%(24/25);58.9%(23/29),93.3%(14/15)及100.0%(15/15);97.8%(219/224),8/10及9/10.结论 PET/CT实现了同机腺苷负荷"N-NH3PET心肌灌注显像与CTA相结合,提高了诊断CAD的准确性.     

瑞加诺生负荷心肌灌注显像诊断冠心病的初步临床研究

目的 探讨瑞加诺生注射液作为负荷药物行核素心肌灌注显像（MPI）诊断冠心病的有效性及安全性。 方法 选取2017年9月至2018年10月于山西医科大学第一医院住院的疑似冠心病的42名受试者进行回顾性研究。采用完全随机法将受试者分为2组:瑞加诺生组[男性8名、女性9名,年龄（59.83±7.88）岁]和腺苷组[男性12名、女性13名,年龄（56.32±7.34）岁],分别行瑞加诺生和腺苷注射液的静息MPI后再行负荷MPI,之后2周内所有受试者均行冠状动脉血管造影（CAG）检查。以CAG结果为标准,分析2组MPI诊断冠心病的效能并观察不良反应。计量资料的组间比较采用两独立样本t检验、配对t检验或方差分析、Wilcoxon Z秩和检验;计数资料的组间比较采用McNemar检验或Fisher's确切概率法;瑞加诺生和腺苷的MPI检查方法的一致性比较采用Kappa检验。 结果 2组一般资料、CAG阳性率及狭窄程度的比较,差异均无统计学意义（t=?1.503~1.201,Z=?1.346~?0.228,Fisher's确切概率法,均P>0.05）。瑞加诺生负荷MPI诊断冠心病的灵敏度为70.00%（7/10）、特异度为87.80%（36/41）、阳性预测值为58.33%（7/12）、阴性预测值为92.31%（36/39）、准确率为84.31%（43/51）;腺苷负荷MPI诊断冠心病的灵敏度为71.43%（10/14）、特异度为86.89%（53/61）、阳性预测值为55.56%（10/18）、阴性预测值为92.98%（53/57）、准确率为84.00%（63/75）,2种MPI方法诊断效能的各项指标的比较差异均无统计学意义（Fisher's确切概率法,均P=1.00）,其分别与CAG结果比较,均存在中度一致性（κ=0.537、0.525,均P<0.001）。药物不良反应为轻微和暂时的,2组间在脸红、胸痛和胸闷、呼吸困难、头晕和头痛、恶心、心悸等不良反应的比较,差异均无统计学意义（Fisher's确切概率法,均P>0.05）,只有腹部不适的差异有统计学意义（Fisher's确切概率法,P=0.044）。 结论 瑞加诺生作为心脏负荷试验药物用于MPI诊断冠心病,与腺苷注射液比较具有相似的有效性及安全性。     

Adenosine stress rubidium-82 PET/computed tomography in patients with known and suspected coronary artery disease

BACKGROUND: Integrated positron emission tomography/computed tomography (PET/CT) is increasingly being utilized for myocardial perfusion imaging (MPI). However, there is a potential for increased imaging artifact compared with standard PET due to the different temporal resolution of PET and CT. We reviewed the diagnostic accuracy of adenosine stress Rb myocardial perfusion PET/CT to detect obstructive coronary artery disease (CAD) on invasive angiography at our institution. METHODS AND RESULTS: Seventy-five patients were included, 23 (13 men, mean age 55.8+/-11.8 years) with low likelihood of CAD and 52 (28 men, mean age 67.1+/-11.4 years) with intermediate to high pretest probability of disease. Coronary angiography was performed only in the latter 52 patients on average within 17 days of the MPI study. The test characteristics of PET/CT MPI were assessed using a threshold of >or=50 and >or=70% stenosis in one or more major coronary artery on invasive angiography. Dedicated software was used for registration, processing, and interpretation. Consensus interpretation of the tomographic PET slices using a 4-point scale (1=definitely normal, 2=probably normal, 3=probably abnormal, 4=definitely abnormal) was done by two readers blinded to clinical information. RESULTS: All MPI studies in the 23 low likelihood patients were normal. In the remaining 52 patients using a stenosis severity>or=50%, global sensitivity and specificity, negative and positive predictive value for detection of CAD were 86, 100, 57, and 100%. Using a stenosis severity>or=70%, these values changed to 90, 83, 71, and 87%. CONCLUSION: Adenosine stress Rb MPI using PET/CT with manual registration demonstrates diagnostic accuracy comparable with that of traditional PET MPI.     

Automated quantitative Rb-82 3D PET/CT myocardial perfusion imaging: Normal limits and correlation with invasive coronary angiography

Background

We aimed to characterize normal limits and to determine the diagnostic accuracy for an automated quantification of 3D 82-Rubidium (Rb-82) PET/CT myocardial perfusion imaging (MPI).

Methods

We studied 125 consecutive patients undergoing Rb-82 PET/CT MPI, including patients with suspected coronary artery disease (CAD) and invasive coronary angiography, and 42 patients with a low likelihood (LLk) of CAD. Normal limits for perfusion and function were derived from LLk patients. QPET software was used to quantify perfusion abnormality at rest and stress expressed as total perfusion deficit (TPD).

Results

Relative perfusion databases did not differ in any of the 17 segments between males and females. The areas under the receiver operating characteristic curve for detection of CAD were 0.86 for identification of ??50% and ??70% stenosis. The sensitivity/specificity was 86%/86% for detecting ??50% stenosis and 93%/77% for ??70% stenosis, respectively. In regard to normal limits, mean rest and stress left ventricular ejection fraction (LVEF) were 67%?±?10% and 75%?±?9%, respectively. Mean transient ischemic dilation ratio was 1.06?±?0.14 and mean increase in LVEF with stress was 7.4%?±?6.1% (95th percentile of 0%).

Conclusion

Normal limits have been established for 3D Rb-82 PET/CT analysis with QPET software. Fully automated quantification of myocardial perfusion PET data shows high diagnostic accuracy for detecting obstructive CAD.     

Prompt-gamma compensation in Rb-82 myocardial perfusion 3D PET/CT

Objective  

To compare the diagnostic accuracy of Rb-82 myocardial perfusion three-dimensional (3D) PET with and without prompt-gamma compensation (PGC).     

82Rb PET myocardial perfusion imaging is superior to 99mTc-labelled agent SPECT in patients with known or suspected coronary artery disease

Purpose

We compared the quality, interpretive confidence and interreader agreement between SPECT and PET myocardial perfusion imaging (MPI) in the same group of patients.

Methods

The study group comprised 27 patients (age 55?±?8.5?years, 12 men) with known or suspected coronary artery disease (CAD) who had undergone gated rest/stress MPI with ^99mTc-labelled agent SPECT (with and without attenuation correction, AC), and subsequent clinical confirmation with ⁸²Rb PET. Three experienced readers blinded to the clinical information interpreted all MPI studies.

Results

Interreader agreement was significantly superior for PET studies than for SPECT studies. Following consensus interpretation, the quality of 22?% of the non-AC SPECT studies, 33?% of the AC SPECT studies and 63?% of the PET studies was assessed as excellent or good (p?=?0.016). Interpretations were definitely normal or abnormal in 7?% of non-AC SPECT studies, 30?% of AC SPECT studies and 85?% of PET studies (p?=?0.046). In 13 patients who had received either invasive coronary angiography or CT angiography with no significant CAD, the true-positive rate for significant CAD was higher for PET, and the true-negative rate was equal for PET and AC SPECT, and lower for non-AC SPECT.

Conclusion

⁸²Rb PET MPI, used as a confirmatory test after SPECT, offers improved image quality, interpretive confidence and interreader agreement.     

Comparison of 2-dimensional and 3-dimensional 82Rb myocardial perfusion PET imaging.

We compared 2-dimensional (2D) and 3-dimensional (3D) (82)Rb PET imaging in 3 different experiments: in a realistic heart-thorax phantom, in a uniformity-resolution phantom, and in 14 healthy volunteers. METHODS: A nonuniform heart-thorax phantom was filled with 111 MBq of (82)Rb injected into the left ventricular (LV) wall. In the LV wall of the cardiac phantom, 3 inserts-1, 2, and 3 cm in diameter-were placed to simulate infarcts. A standard rest cardiac PET imaging protocol in 2D and 3D modes was used. Following the same protocol, a uniformity-resolution phantom with uniformly distributed activity of 1,998 MBq and 740 MBq of (82)Rb in water was used to obtain 2D PET images and 3D PET images, respectively. All 2D volunteer studies were performed by injecting 2,220 MBq of (82)Rb intravenously. For half the volunteers, 3D studies were performed with a high dose (HD) (2,220 MBq) of (82)Rb; for the remainder of the 3D studies, a low dose (LD) (740 MBq) of (82)Rb was used. In the 2D and LD 3D studies, there was a delay of 2 min and 3 min, respectively, followed by a 6-min acquisition. In the HD 3D volunteer studies, there was a delay of 5 min followed by a 6-min acquisition. Circumferential profiles of the short-axis slices and the contrast of the inserts were used to evaluate the cardiac phantom PET images. The transaxial slices from the uniformity-resolution phantom were evaluated by visual inspection and by measuring uniformity. The human studies were evaluated by measuring the contrast between LV wall and LV cavity, using linear profiles and visual analysis. RESULTS: In the cardiac phantom study, circumferential profiles for the 2D and 3D images were similar. The contrast values for the 1-, 2-, and 3-cm inserts in the 2D study were 0.19 +/- 0.03, 0.34 +/- 0.05, and 0.61 +/- 0.03, respectively. The respective contrast values in the 3D study were 0.15 +/- 0.02, 0.36 +/- 0.04, and 0.52 +/- 0.05. In the uniformity-resolution phantom study, the coefficients of variation, calculated for a representative uniform slice, were 5.3% and 7.6% for the 2D and 3D studies, respectively. For the 7 volunteers on whom HD 3D was used, the mean 2D contrast was 0.33 +/- 0.08 and the mean HD 3D contrast was 0.35 +/- 0.08 (P = not statistically significant). For the other 7 volunteers, on whom LD 3D was used, the mean 2D contrast was 0.39 +/- 0.06 and the mean LD 3D contrast was 0.39 +/- 0.10 (P = not statistically significant). In the tomographic slices, the 2D and 3D images and polar plots were similar. CONCLUSION: When obtained with a PET system having a high counting-rate performance, 2D and 3D (82)Rb PET cardiac images are comparable. LD 3D imaging can make (82)Rb PET cardiac imaging more affordable.     

Prediction of multivessel coronary artery disease and candidates for stress-only imaging using multivariable models with myocardial perfusion imaging

Annals of Nuclear Medicine - Selecting patients with coronary multivessel disease (MVD) or no stenosis using myocardial perfusion imaging (MPI) is challenging. We aimed to create a model to predict...     

Dobutamine stress myocardial perfusion imaging in coronary artery disease.

The accurate noninvasive diagnosis and functional evaluation of coronary artery disease is an important step in selecting the appropriate management strategy. Dobutamine stress myocardial perfusion imaging is an alternative to exercise in patients with limited exercise capacity. In many centers, the test is performed on patients who have a contraindication for vasodilator stress testing. Recent studies have shown hyperemia induced by the standard dobutamine-atropine stress test is not less than hyperemia induced by dipyridamole. The feasibility of the test is 90% and is often higher in patients without beta-blocker therapy. The safety of the test has been well studied and was also demonstrated in specific patients groups, such as patients with left ventricular dysfunction, the elderly, and heart transplant recipients. The diagnostic accuracy has been demonstrated in patients with and without myocardial infarction and in specific groups such as those with hypertension, left ventricular hypertrophy, and heart transplant recipients and after revascularization. The technique has a high sensitivity for prediction of functional recovery in patients with myocardial dysfunction referred for revascularization. The presence and severity of myocardial perfusion abnormalities assessed by this method are powerful predictors of cardiac events, incremental to clinical data. This article describes the methodology, safety, feasibility, diagnostic accuracy, and prognostic value of dobutamine stress myocardial perfusion imaging in patients with known or suspected coronary artery disease, with additional considerations for the application of the test in specific patient groups.     

慢性稳定型冠心病的核素心肌灌注显像临床应用进展

多项临床试验证明,核素心肌灌注显像在冠心病诊断、危险度分层、预后判断、病人处理方案等方面具有突出的作用和优越的价值。在ACC/AHA(美国心脏病学院/美国心脏学会)有关冠心病和核心脏病学指南中,心肌灌注显像的上述作用得到了充分肯定。合理应用该项技术可以提高对冠心病诊断、处理的整体水平,并使有限的医疗资源得到更合理利用,这在我国目前显得十分迫切和需要。     

PET心肌灌注显像测定心肌血流量及冠状动脉血流储备的研究进展

PET心肌灌注显像可绝对定量测定局部心肌血流量（MBF）和冠状动脉血流储备（CFR）。由于显像剂半衰期短,允许在短时间内重复进行PET心肌灌注显像,获得静息态、冷加压试验和药物负荷试验等不同状态下的MBF,进而评价冠状动脉血管内皮依赖性和非依赖性的CFR功能。在早期诊断冠心病,准确诊断冠状动脉多支病变,评价微血管病变,早期检测冠状动脉内皮细胞功能异常及CFR功能的异常,估测预后,帮助临床治疗方案的制定以及检测疗效等方面,PET心肌灌注显像有重要的临床价值。该文将介绍PET心肌灌注显像相关知识及其在心血管领域的主要应用。     

Segmental quantitative myocardial perfusion with PET for the detection of significant coronary artery disease in patients with stable angina

Purpose

The goal of this study is to determine the technical accuracy of segmental perfusion parameters assessed with quantitative cardiac PET imaging in the evaluation of coronary artery disease (CAD) in patients with stable angina.

Methods

A cohort of patients who participated in the EVINCI protocol underwent an evaluation of coronary anatomy by invasive coronary angiography (ICA) and/or coronary computed tomography angiography (CCTA) and PET myocardial perfusion imaging with H₂ ¹⁵O, ¹³NH₃ or ⁸²Rb. PET studies were analyzed by two independent observers blinded to clinical and instrumental data, and classified as positive or negative for significant CAD using only segmental perfusion measurements and cut-off values from literature.

Results

On a per-patient basis, the overall inter-observer agreement on PET results was 90 % (kappa?=?0.79), indicating substantial agreement. On a per-vessel basis, the inter-observer agreement on PET results was 88 % (kappa?=?0.74) in the RCA territory, 94 % (kappa?=?0.84) in the LAD territory and 94 % (kappa?=?0.85) in the LCX territory.Segmental PET measurements correctly identified 85 % of the patients, resulting in a global sensitivity of 86 %, a specificity of 84 %, a positive predictive value (PPV) of 69 % and a negative predictive value (NPV) of 93 %.In vessel-based analyses, quantitative perfusion parameters had a sensitivity, specificity, PPV and NPV of 92 %, 82 %, 42 % and 99 %, respectively, for the detection of significant coronary stenoses in all major coronary arteries.

Conclusions

The assessment of absolute myocardial perfusion parameters measured at a segment level lead to reliable and accurate identification of patients with significant coronary stenosis at ICA and/or CCTA.

     

静息/负荷82Rb PET门控心肌灌注显像定量分析的价值

目的 探讨门控和定量分析技术在82Rb PET心肌灌注显像中的应用价值.方法 对32例临床可疑冠心病患者进行静息/腺苷负荷82Rb PET门控心肌灌注显像.原始数据按常规处理成断层图像,再应用定量分析软件Emory Cardiac Toolbox(ECTb)进行定量分析.由3位有经验的核医学科医师分别对图像质量(优、良、一般、差、无法分析)、左心室射血分数(LVEF)的可信程度(同意、基本同意、不确定、基本不同意、不同意)、左心室功能的其他指标对诊断的价值(很有帮助、有帮助、不确定、基本无帮助、无帮助)进行评价.将观察指标分为肯定组和否定组,分别计算其百分率和90%可信区间.结果 192组分析结果中,图像质量优良者共计160组,占83.3%(160/192),其95%可信区间为78.1%～88.6%;图像质量为一般和差的共计32组,占16.7%(32/192),其95%可信区间为11.4%～21.9%.对LVEF的结果表示同意和基本同意者共计164组,占85.4%(164/192),其95%可信区间为80.4%～90.4%;认为不确定和基本不同意或不同意者共计28组,占14.6%(28/192),其95%可信区间为9.6%～19.6%.应用定量分析软件获得的除LVEF以外左心室功能的其他指标,认为很有帮助和有帮助者共计102组,占53.1%(102/192),其95%可信区间为46.1%～60.2%;不确定和基本无帮助或无帮助者90组,占46.9%(90/192),其95%可信区间为39.8%～53.9%.结论 门控和定量分析技术有助于PET图像阅片者作出更正确的诊断.