Correlation of PET/CT Standardized Uptake Value Measurements Between Dedicated Workstations and a PACS-Integrated Workstation System

Purpose This study was conducted to evaluate the clinical utility of a Positron Emission Tomography/Computed Tomography (PET/CT) analysis module of a picture archiving communication system (PACS) workstation in comparison to a dedicated PET/CT interpretation workstation. Materials and Methods The study included 32 consecutive patients referred for an [¹⁸F] Fluro-2-Deoxy-D-Glucose (¹⁸F-FDG) PET/CT at our institution. Images were reviewed at dedicated PET/CT and at PACS-integrated workstations. Mean standardized uptake values (SUVs) were calculated for the liver and the lung. Maximum SUVs were recorded for the bladder and an index lesion with the highest FDG uptake. The time spent for SUV measurements was recorded. Correlation of the SUV measurements was calculated with the Pearson coefficient. Results Pearson coefficients between the workstations ranged from 0.96 to 0.99 for bladder and lesion maximum SUVs. For liver and lung average SUVs, the coefficients varied from 0.53 to 0.98. The mean time spent to perform the four SUV measurements was 122.6 s for the dedicated workstations and 134.6 s for the PACS-integrated system. Conclusion The correlation of SUV measurements between dedicated PET/CT and PACS-integrated workstations is very good, especially for maximum SUVs. For routine reading of PET/CT scans, a PACS workstation with a PET/CT analysis module offers an excellent alternative to the use of a dedicated PET/CT workstation.     

Clinical use of PET/CT in thyroid cancer diagnosis and management

The incidence of thyroid cancer is low, but when it occurs, it is mainly of the papillary histopathological type. Although PET/CT has a limited role in the diagnosis, it plays a significant role in the overall post-surgery management of a patient with thyroid cancer. This follow-up role is important, especially in patients with elevated serum thyroglobulin, but negative radioiodine whole body scans. There is increasing evidence that PET/CT should be a part of routine care in the Tg positive Radioiodine scan negative patient.     

PET／CT显像的图像融合精度测试研究

目的:通过模拟和临床实际应用状态,测试3D全身显像方式PET/CT显像图像融合精度.方法:用测试模型及其配套的22Na固体点源,模拟人体宽度和厚度,采集点源PET/CT图像数据;然后将相同的点源置于检查床两测的床垫下,在检查床无负重和负重85 kg时,分别采集PET/CT图像数据.重建图像后,在PET/CT融合图像的三个断层面分别寻找CT和PET点源图像的中心,测量二者中心偏差的mm数,即PET/CT图像融合精度.结果:PET和CT两种模态融合图像肉眼可见较明显的错位.模型点源PET/CT融合图像最大偏差为(4.25±0.26)mm、检查床无负重时为(3.96±0.26)mm,检查床负重85 kg时为(5.36±0.26)mm.结论:本研究方法可以比较精确地测量PET/CT图像融合精度,并有效地指导PET/CT仪器的验收和故障检测等.     

基于小波变换的CT/PET图像融合最佳参数研究

为了提高基于小波变换图像融合的性能,在图像融合规则相对固定的情况下,提出一种确定最佳小波基函数和分解层数的方法。从图像的信息熵出发,通过比较低频子带图像熵差与原始图像熵差的接近程度,选择每一种小波基所对应的最佳分解层数;在小波分解层数确定的情况下,结合图像融合评价方法,选择最佳的小波基函数。与引入融合效果的评价构成一个闭环系统来确定小波参数相比,该方法极大地简化了判别过程;将该方法应用于CT/PET图像融合,获得了较好的融合效果。实验结果表明,该方法简单可行,对基于小波变换图像融合的小波参数选取有一定的指导意义。     

PET/CT图像呼吸运动伪影校正研究进展

在正电子发射断层扫描成像/计算机断层扫描成像(PET/CT)扫描时,患者的呼吸运动造成胸腹部图像的伪影.呼吸运动伪影使得PET图像质量下降,肿瘤体积的估计值偏高,肿瘤组织的放射性定量分析不准确,因此严重影响胸腹部肿瘤的诊断和治疗计划的制定.PET/CT图像的呼吸运动伪影校正问题成为了近年来的一项重要课题.综述现有的PET/CT图像呼吸运动伪影校正方法,主要包括呼吸门控技术、基于图像配准的方法、基于图像重建和原始数据的方法,以及基于反卷积的图像恢复方法.在展望研究发展趋势的同时,就某些方法提出了可能的改进方案.     

Artefacts of PET/CT images

Positron emission tomography (PET) is a non-invasive imaging modality, which is clinically widely used both for diagnosis and accessing therapy response in oncology, cardiology and neurology.Fusing PET and CT images in a single dataset would be useful for physicians who could read the functional and the anatomical aspects of a disease in a single shot.The use of fusion software has been replaced in the last few years by integrated PET/CT systems, which combine a PET and a CT scanner in the same gantry. CT images have the double function to correct PET images for attenuation and can fuse with PET for a better visualization and localization of lesions. The use of CT for attenuation correction yields several advantages in terms of accuracy and patient comfort, but can also introduce several artefacts on PET-corrected images.PET/CT image artefacts are due primarily to metallic implants, respiratory motion, use of contrast media and image truncation. This paper reviews different types artefacts and their correction methods.PET/CT improves image quality and image accuracy. However, to avoid possible pitfalls the simultaneous display of both Computed Tomography Attenuation Corrected (CTAC) and non corrected PET images, side by side with CT images is strongly recommended.     

造影剂的使用对PET/CT中CT衰减校正方式的影响和修正算法

PET/CT扫描一般直接将CT透射扫描数据用于PET发射扫描的衰减校正,但是在有口服造影剂使用的场合,常规的衰减校正算法对PET扫描结果会带来约20%的正偏差。本文针对这种情况提出一种修正算法,可以把造影剂增强区域的CT扫描值正确转换为511 keV上的衰减值,从而消除PET成像偏差。     

The role of 18F-FDG PET/CT in the evaluation of gastric cancer recurrence after curative gastrectomy

Purpose

¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) scans are frequently performed for the screening or staging of malignant tumors. This study aimed to assess the usefulness of ¹⁸F-FDG PET/CT in detection of gastric cancer recurrence after curative gastrectomy.

Materials and Methods

Eighty nine patients who had undergone curative gastrectomy due to gastric cancer and had ¹⁸F-FDG PET/CT and contrast CT scans within 2 weeks for surveillance in asymptomatic patients (n = 11) or to clarify suspected recurrence (n = 78) were consecutively collected and retrospectively analyzed. They had clinical follow-up for at least 12 months after PET/CT and CT scans.

Results

Fifteen of the 89 patients (16.9%) were diagnosed with recurrent gastric cancer in 21 organs. Forty one organs showed an increase in FDG uptake, and only 9 of these organs were diagnosed with recurrent gastric cancer by ¹⁸F-FDG PET/CT. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of the ¹⁸F-FDG PET/CT were 42.9%, 59.7%, 29.3%, 78.2%, and 57.3%, respectively. On the CT scan, 18 of 21 recurrent gastric cancers were detected, and 7 cases were in agreement with the ¹⁸F-FDG PET/CT. The sensitivity and specificity of the CT scan were 85.8% and 87.3%, respectively, which are superior to the ¹⁸F-FDG PET/CT. When we diagnosed a recurrence based on either ¹⁸F-FDG PET/CT or CT scans, the sensitivity increased to 95.2% and the specificity decreased to 45.6%, when compared with the contrast CT scan alone.

Conclusion

¹⁸F-FDG PET/CT is an insufficient diagnostic method in detection of recurrence after curative gastrectomy, and even less accurate than contrast CT scan alone.     

99Tcm-MDP骨显像SUV值在鼻咽癌颅底侵犯诊断价值初步研究

目的通过传统99Tc^m-MDP(锝-99亚甲基二膦酸盐)全身骨单光子发射计算机断层成像术/电子计算机断层扫描(single-photon emission computed tomography/computed tomography,SPECT/CT)显像,计算鼻咽癌患者颅底骨质基于放射活度的标准摄取值(standardized uptake value,SUV),观察99Tc^m-MDP全身骨SPECT/CT显像中的颅底区域SUV对鼻咽癌颅底骨质侵犯的增益价值及阳性诊断的最佳SUV界值范围。方法选取2016年6月至2017月1月本院确诊鼻咽癌并行全身骨显像患者51例,男40例,女11例,年龄27~77岁,平均年龄50.4±10.7岁,其中28例鼻咽部磁共振成像(magnetic resonance imaging,MRI)证实伴颅底骨质侵犯,23例鼻咽部MRI证实未见颅底骨质侵犯。通过定量分析软件分析融合图像,勾勒感兴趣区(region of interest,ROI),测得颅底骨质侵犯组及颅底骨质非侵犯组的最大标准化摄取值(SUVmax)及平均标准化摄取值(SUVmean),并采用t检验和受试者工作特征曲线(receiver operating characteristic curve,ROC)计算两组的界值。结果颅底骨质侵犯组28例SUVmax平均值为3.17(标准差为1.38);颅底骨质非侵犯组23例SUVmax平均值为1.34(标准差为0.39)。两组比较,t=6.129,P<0.001,差异有统计学意义。颅底骨质侵犯组28例SUVmean平均值为0.45(标准差为0.16);颅底骨质非侵犯组23例SUVmean平均值为0.9(标准差为0.37)。两组比较,t=5.80,P<0.001,差异有统计学意义。51例鼻咽癌患者的SUVmax按颅底骨质侵犯组和颅底骨质非侵犯组进行ROC曲线分析,曲线下面积为0.961,阈值为1.85时,灵敏度为89%,特异性为92%;51例鼻咽癌患者的SUVmean按颅底骨质侵犯组和颅底骨质非侵犯组进行ROC曲线分析,曲线下面积为0.904,阈值为0.55时,灵敏度为82%,特异性为79%。结论全身骨SPECT/CT显像测得基于放射活度的SUV值与鼻咽癌颅底骨质侵犯与否具有良好的相关性,因此SPECT/CT SUV值为鼻咽癌全身骨SPECT/CT显像提供了一种新的具有较高的准确性辅助诊断信息,初步得出在SUVmax为1.85时其对鼻咽癌颅底骨质侵犯诊断价值较高,故SUVmax为1.85可作为最佳诊断阈值。     

原发性甲状腺淋巴瘤18F-FDG PET/CT的影像特点

目的 探讨原发性甲状腺淋巴瘤(PTL)的18F-FDG PET/CT影像表现.方法 回顾2009年11月至2013年8月淋巴瘤患者805例,病理证实PTL者12例,分析18F-FDG PET/CT图像特点,以及SUVmax值及与临床指标相关性.结果 PTL好发于中老年妇女,弥漫大B细胞淋巴瘤(DLBCL)及粘膜相关淋巴瘤(MALToma)常见.18F-FDG PET/CT图像显示甲状腺双侧或单侧塑形增大,病灶密度弥漫性均匀性减低49.4±11.8HU,且代谢明显增高(SUVmax均值12.4±8.7),常伴占位效应及高代谢淋巴结.SUVmax值不受年龄、性别、B症状、分期影响(P＞0.05),但与IPI评分具有相关性(P=0.018).结论 18F-FDG PET/CT显像有助于PTL的早期诊断.     

Metabolic Super Scan in 18F-FDG PET/CT Imaging

A 50-yr-old man presented with intermittent hemoptysis and was diagnosed small cell lung cancer. ¹⁸F-FDG PET/CT for staging demonstrated extensive hypermetabolic lesions throughout the skeleton and liver. Interestingly, skeletal muscles of limbs, mediastinum, bowel, and especially brain showed very low FDG uptake. Because of some characteristics in common with super scan on skeletal scintigraphy, this case could be considered as ''metabolic super scan''.     

Optimisation of whole-body PET/CT scanning protocols

Positron emission tomography (PET) has become one of the major tools for the in vivo localisation of positron-emitting tracers and now is performed routinely using (18)F-fluorodeoxyglucose (FDG) to answer important clinical questions including those in cardiology, neurology, psychiatry, and oncology. The latter application contributed largely to the wide acceptance of this imaging modality and its use in clinical diagnosis, staging, restaging, and assessment of tumour response to treatment. Dual-modality PET/CT systems have been operational for almost a decade since their inception. The complementarity between anatomic (CT) and functional or metabolic (PET) information provided in a "one-stop shop" has been the driving force of this technology. Although combined anato-metabolic imaging is an obvious choice, the way to perform imaging is still an open issue. The tracers or combinations of tracers to be used, how the imaging should be done, when contrast-enhanced CT should be performed, what are the optimal acquisition and processing protocols, are all unanswered questions. Moreover, each data acquisition-processing combination may need to be independently optimised and validated. This paper briefly reviews the basic principles of dual-modality imaging and addresses some of the practical issues involved in optimising PET/CT scanning protocols in a clinical environment.     

18F-FDG PET/CT在甲状腺结节中的诊断价值

目的 探讨18F-FDG PET/CT在甲状腺良恶性结节中的诊断价值.方法 回顾性分析了48例(男17例,女31例)于本院行18F-FDG PET/CT显像的甲状腺结节患者,所有结节均得到病理证实.利用ROC曲线选取PET/CT半定量指标最大标准摄取值(SUVmax)最佳诊断界值.根据病灶的视觉分级、摄取形态、SUVmax值、CT衰减程度、钙化、突出于甲状腺边界外及病灶边缘是否清晰等七项指标进行综合评分,比较这种综合评分方法与单纯利用SUVmax值判断良恶性的诊断效能,并比较良恶性两组间SUVmax值是否具有差异.最后利用Logistic回归分析七项指标与良恶性结节的相关性.结果 ①SUVmax诊断甲状腺结节的最佳界值为4.71,此时18F-FDG诊断甲状腺恶性病变的灵敏度为80.6％,特异度为75％;②将SUVmax与病理结果对照,发现恶性组SUVmax较良性组明显增高,但恶性组与良性组有重叠;③结合七项指标综合判断结节良恶性的诊断效能较单独利用SUVmax判断良恶性的诊断效能无明显差异(P=0.09);④七项评价指标中SUVmax及CT衰减程度与良恶性相关,对良恶性诊断具有一定价值.结论 ①SUVmax最佳诊断界值为4.71;②良恶性两组间SUVmax差异具有统计学意义;③联合PET及CT多项指标综合诊断不能提高诊断效能;④SUVmax大小及CT中表现为低密度与恶性结节相关,CT中表现为极低密度与良性结节相关,对于良恶性鉴别诊断有一定意义.     

18F-FDG PET-CT在确定乳腺癌术前诊断与分期中的临床价值

目的 探讨18F-FDG PET-CT在确定乳腺癌术前诊断及分期中的临床价值.方法 2012年10月至2014年12月我院外科收治的均经病理检查确诊为乳腺癌患者中,有32例患者在术前进行了全面PET-CT检查,检查范围包含乳房原发病灶、区域淋巴结及周身脏器.最后将手术病理与PET-CT检查结果进行比较分析.结果 32例患者中,18F-FDG PET-CT检查结果是:Ⅰ期是3例,Ⅱ期22例,Ⅲ期4例,Ⅳ期2例,良性肿块1例(最后病理证实为浸润性小叶癌).Ⅰ期-Ⅱ期25例患者中PET-CT发现腋下淋巴结转移15例,同侧内乳淋巴结2例,锁骨上窝淋巴结1例.手术后病理或针吸活检病理提示:浸润性导管癌24例,浸润性小叶癌5例,导管内原位癌2例,高分化腺癌1例,腋下淋巴结转移14例,淋巴结转移正确率为93.3％ (14/15).结论 18F-FDG PET-CT检查对于诊断乳腺癌具有较强的检测能力,尤其是在诊断腋窝淋巴结转移及远处转移中更具优势,对于乳腺癌术前诊断及分期具有较高的临床价值.     

18F-FDG PET/CT与CT诊断胃癌淋巴结转移直接比较的系统评价

目的 采用Meta分析和直接比较方法系统评价18F-FDG PET/CT与CT对胃癌淋巴结转移的诊断价值.方法 使用计算机系统检索中国期刊全文数据库、中文科技期刊数据库、万方数据库、PubMed、Embase、The Cochrane Library,从建库至2016年11月,搜索直接比较18F-FDG PET/CT与CT诊断胃癌淋巴结转移的诊断性比较试验.用Meta-Disc1.4软件进行分析,计算两种影像学诊断方法的合并灵敏度(sensitivity,SEN)、合并特异性(specificity,SPE)、合并阳性似然比(positive likelihood ratio,+LR)、合并阴性似然比(negative likelihood ratio,-LR),诊断优势比(diagnostic OR,DOR),并绘制SROC (summary receiver operating characteristic)曲线,计算曲线下面积(area under curve,AUG).结果 最终共纳入9篇文章,Meta分析结果显示,18F-FDG PET/CT对胃癌淋巴结转移诊断的合并SEN为0.51(95％ CI =0.47～0.55),合并SPE为0.92(95％ CI =0.89 ～0.94),合并+LR为5.77(95％ CI =4.38 ～7.59),合并-LR为0.54(95％ CI =0.45 ～0.64),DOR为12.71(95％ CI =8.97～ 18.01),AUC为0.8101.CT诊断的合并SEN为0.71(95％ CI=0.67～ 0.74),合并SPE为0.82(95％ CI =0.78 ～0.84),合并+LR为3.52(95％ CI=2.52 ～4.93),合并-LR为0.37(95％CI=0.32～0.44),DOR为10.73(95％ CI =7.35 ～ 15.66),AUC为0.8176.结论 18F-FDG PET/CT显像诊断胃癌淋巴结转移的灵敏度比CT低,但其特异性较好,有更高的诊断价值,可作为胃癌淋巴结转移的临床诊断方法之一.     

用于儿科PET/CT检查的参数优化选择方法

目的 目前儿科β-2-[F]氟-2-脱氧-D-葡萄糖（18F-FDG）剂量和采集时间一般是按照成人的参数推算出来.本研究目的是对在不影响图像诊断质量的前提下,行儿科正电子发射型计算机断层显像（PET）/CT检查时,缩短采集时间或降低18F-FDG注射用量的可行性进行初步研究.方法 对36例患者（体质量为13～89 kg,平均体质量（46.51±5.63） kg;年龄3～14岁,平均年龄（9.22±3.16）岁）行36次全身18F-FDG PET/CT扫描,按照5.3 MBq/kg（0.14 mCi/kg）计算注射18F-FDG,采用VIP record采集模式,180 s/视野（FOV）;对于每次检查,VIP record记录的数据按照采集时间的减少（160、140、120、100、80、60 s/FOV的数据按照180 s/FOV的数据来模拟计算）,分别被缩减以形成不同采集时间下的图像.随机挑选168幅PET图像以及相对应的CT图像,通过6位影像学专家阅片,对全身存在的病灶进行分析,分别对颈部、胸部、腹部、骨等部位病灶的符合率进行对比,并对主观可信度以及客观准确度进行全面评估.结果 所有检查均以最大采集时间作为分级标准和检查准确度的参考标准.对于体质量＞30 kg的受检者,当采集时间＞120 s/FOV时,所有病灶均可以检测出来,采用120 s/FOV以下的参数进行采集时,病灶检测准确度会大大降低;对于体质量＜30 kg的受检者,当采集时间＞140s/FOV时,所有病灶均可以检测出来,采用140 s/FOV以下的参数进行采集时,病灶检测准确度会大大降低.结论 应用GE Discovery STE PET/CT行儿科检查时,采用减少18F-FDG用量替代减少采集时间,如果采用180s/FOV时,对于体质量＞30 kg的受检者,18F-FDG的用量可降低33.33％;对于体质量＜30 kg的受检者,18F-FDG的用量可降低22.22％,而且不会损失图像诊断质量.所需扫描全部时间的减少意味着可以减少运动伪影,提高受检者舒适度以及减少所需镇静的时间;另外,通过减少18F-FDG用量,还可降低受辐射的风险     

The reduction of artifacts due to metal hip implants in CT-attenuation corrected PET images from hybrid PET/CT scanners

CT beam hardening artifacts near metal hip implants may erroneously enhance or diminish radiotracer uptake following CT attenuation correction (AC) of PET images. An artifact reduction algorithm (ARA) was developed to reduce metal artifacts in CT-based AC-PET. The algorithm employed a Bayes classifier to identify beam-hardening artifacts, followed by a partial correction of the attenuation map. ARA was implemented on phantom and patient 18F-FDG studies using a clinical PET/CT scanner. In phantom studies ARA successfully removed two artifacts of erroneously elevated uptake near a stainless steel hip prosthesis which were depicted in the standard CT-AC PET. ARA has also identified two targets absent on the scanner PET images. Target-to-background ratios were 1.5-3 times higher for ARA-PET than scanner images. In a patient study, metal artifacts were of lower intensity in ARA-PET as compared to standard images. Potentially, ARA may improve detectability of small lesions located near metal hip implants.     

Aortitis in giant cell arteritis: diagnosis with FDG PET/CT and agreement with CT angiography

Objectives

To assess the detection rate of aortitis in giant cell arteritis (GCA) with fluorodeoxyglucose positron emission tomography/computed tomography (PET) and to compare the findings with CT angiography (CTA).

Detecting the recurrence of gastric cancer after curative resection: comparison of FDG PET/CT and contrast-enhanced abdominal CT

The purpose of this study was to evaluate the value of fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) for detecting the recurrence of gastric cancer. We performed a retrospective review of 139 consecutive patients who underwent PET/CT and contrast-enhanced abdominal CT (CECT) for surveillance of gastric cancer after curative resection. Recurrence of gastric cancer was validated by histopathologic examination for local recurrence or serial imaging study follow-up with at least 1 yr interval for recurrence of distant metastasis form. Twenty-eight patients (20.1%) were confirmed as recurrence. On the patient based analysis, there was no statistically significant difference in the sensitivity, specificity and accuracy of PET/CT (53.6%, 84.7%, and 78.4%, respectively) and those of CECT (64.3%, 86.5%, and 82.0%, respectively) for detecting tumor recurrence except in detection of peritoneal carcinomatosis. Among 36 recurrent lesions, 8 lesions (22.2%) were detected only on PET/CT, and 10 lesions (27.8%) only on CECT. PET/CT had detected secondary malignancy in 8 patients. PET/CT is as accurate as CECT in detection of gastric cancer recurrence after curative resection, excepting detection of peritoneal carcinomatosis. Moreover, additional PET/CT on CECT could improve detection rate of tumor recurrence and provide other critical information such as unexpected secondary malignancy.