经济型PET/CT与双源CT异机融合在肿瘤诊断中的应用

目的通过对比分析经济型PET/CT与双源CT异机融合的图像质量,探讨异机融合的临床应用价值。方法对29例可疑肿瘤或肿瘤复发转移患者行经济型PET/CT的PET与双源CT图像融合,并与同机融合图像质量进行对比分析。结果两种方法均检出原发灶和转移灶共46个,异机融合图像质量优于同机融合(χ2=14.743,P<0.001)。结论双源CT与经济型PET/CT异机融合,方便实用,优势互补,可提高图像质量,对临床诊断和治疗肿瘤有重要价值。     

基于特征配准的[PET+CT＋MR] “三机三维”影像一体化融合尝试

目的尝试以基于图像特征的二维图像配准方法,实现PET、MR和CT异机图像之间的精确三维融合。方法输入PET/CT/MR原始数据后,采用数字化格式转换,设计"9点3面"立体定位法进行配准,在Mimics实时工作站按照信息交互自动融合模式并通过信号叠加技术施行图像融合。结果以头、胸、腹为实例交叉试验[CT+MR]、[PET+MR]、[PET+CT]和[PET+CT+MR]立体图像的异机融合,生成了同时分辨软硬组织病灶性质和位置的互补影像。结论在现阶段,此种异机融合方法是对同机成像功用的必要补充。     

CT、MRI及与PET融合显像评价宫颈癌分期及淋巴结转移中的应用进展

传统影像学检查方法(CT、MRI)在宫颈癌分期及淋巴结转移的诊断方面应用较为广泛,对制定治疗方案、改善预后和降低死亡率有重要的作用。近年来,随着分子影像技术的发展,多模态分子影像技术(PET/CT及PET/MR)被逐渐应用于宫颈癌的诊断并指导治疗。本文对CT、MRI及与PET融合显像技术在宫颈癌分期及淋巴结转移评价中的临床应用进行综述。     

PET/MRI融合图像诊断妇科恶性肿瘤盆腔复发

目的 探讨PET/MRI融合图像诊断妇科肿瘤术后盆腔复发、转移的效能。方法 回顾性分析38例妇科恶性肿瘤患者术后PET/CT、盆腔MRI图像,并进行PET与MRI图像的融合,比较PET/CT、盆腔MRI及PET/MRI融合诊断盆腔局部复发、转移的价值。结果 38例患者中23例有肿瘤复发、转移,PET/MRI融合图像诊断盆腔复发、转移有较高的敏感度、特异度和准确率,且PET/MRI融合诊断盆腔局部复发的准确率高于MRI（94.73% vs 73.68%,P=0.025）。结论 PET/MRI融合结合了PET和MRI的优势,在诊断妇科肿瘤患者盆腔复发、转移中具有重要的价值。     

18F-FDG PET/CT半定量分析诊断颈部淋巴结转移癌的价值

目的 探讨18 F-FDG PET/CT诊断颈部淋巴结转移癌的价值.方法 回顾性分析48例颈部淋巴结肿大患者的CT、PET及PET/CT图像,在CT图像上分别以淋巴结最短径＞0.5 cm(A标准)、最短径＞1.0 cm(B标准)及最长径＞1.0 cm(C标准)为判定淋巴结转移的诊断标准;在PET图像上,以淋巴结出现异常18F-FDG摄取浓聚灶最大标准化摄取值(SUVmax)＞2.5(D标准),SUVmax＞1.93(E标准)、TSUVmax/NSUVmax＞3.11(F标准)为判定淋巴结转移的诊断标准;在PET/CT图像上,将结合CT图像A标准及PET图像E标准确定的G标准为判定以淋巴结转移的诊断标准.以病理诊断为标准,比较不同影像标准在颈部淋巴结转移中的诊断价值.结果 颈部阳性淋巴结与阴性淋巴结在最长径、最短径、SUVmax值之间的差异均有统计学意义.7种标准中,PET(E标准)及PET/CT(G标准)具有较高的诊断准确率与病理吻合度,与单纯CT比较具有较高诊断价值.不同PET及PET/CT诊断标准差异无统计学意义.结论 18F-FDG PET/CT对颈部淋巴结转移的诊断具有较高的临床价值.     

18F-FDG PET/CT诊断多发性骨髓瘤

目的 探讨18F-FDG PET/CT对多发性骨髓瘤(MM)的诊断价值.方法 MM患者20例,均于治疗前进行18F-FDG PET/CT全身显像.所有PET、CT及PET/CT融合图像均通过融合软件进行帧对帧对比分析.肿瘤病灶根据穿刺活组织病理学检查、多种影像学检查和临床随访结果 诊断.结果 19例18F-FDG PET/CT检出阳性病灶(95.00%),SUV为2.81±0.98(1.30～6.00), 共检出病灶303处,其中PET有222处表现为18F-FDG摄取增高(73.27%),CT检出268处灶状溶骨性改变(88.45%).PET和CT同时检出的病灶为187处(61.72%);PET检出而同机CT未检出的病灶35处(11.55%);同机CT检出而PET未检出病灶81处(26.73%).结论 18F-FDG PET/CT对于MM的诊断及评价全身累及范围具有一定价值.     

宫颈癌75例18F-FDG PET/CT检查的护理

目的 总结宫颈癌患者应用氟代脱氧葡萄糖(18F-FDG)进行PET/CT显像检查的护理要点.方法 应用18F-FDG对75例宫颈癌患者行PET/CT显像定性诊断,显示肿瘤部位及范围,同时进行全程的护理配合,包括检查前的心理、饮食及药物等护理;检查中加强患者病情观察及健康宣教.结果 PET/CT图像清晰,能清晰观察到宫颈病变及其转移灶.结论 完善及有针对性的全程护理是PET/CT检查获得高质量图像的重要保证.     

肺部PET／CT150例分析

正电子发射体层摄影／计算机体层摄影（PET／CT）是正电子发射体层摄影与传统CT同机融合，从功能代谢角度、分子基因水平研究和诊断疾病，代表影像医学最近发展。现将我院2002-2005年间肺部单发结节PET／CT150例分析如下。     

全身18F-FDG PET/CT在原发灶不明的颈部转移癌中的应用价值

目的初步探讨全身18氟[18F]-FDGPET/CT在原发灶不明的颈部转移癌中的应用价值。方法对42例原发灶不明的颈部转移癌患者行全身18F-FDGPET/CT检查,分别对单独PET图像、单独CT图像及PET/CT融合图像进行判读,所得结果与病理和/或随访结论比较。结果PET/CT对原发灶检出率优于单独PET及单独CT(灵敏度分别为59.5%(25/42)、35.7%(15/42)、及23.8%(10/42),χ2值分别为8.100及13.067,P<0.01,均有显著统计学差异)。28.6%患者(12/42)经PET/CT检查后发现分期改变(包括4例未找到原发灶患者)。在29例已行颈部肿块切除病例中,有5例局部仍可见异常高代谢灶,提示肿瘤残余。PET/CT、单独PET及单独CT假阳性率分别为4.8%(2/42)、16.7%(7/42)及9.5%(4/42)。结论18F-FDGPET/CT全身显像对于寻找原发灶不明的颈部转移癌患者的原发灶、了解肿瘤生物学特性及全身侵犯情况有重要的临床价值,有利于临床及时制定或调整治疗方案。     

18F-FDG PET/CT显像对胃癌的诊断价值及对临床决策的影响

目的:探讨18F-FDG PET/CT全身显像在胃癌治疗前诊断的价值以及显像结果对治疗决策的影响。方法:对临床怀疑为胃癌的81例患者在治疗前进行18F-FDG PET/CT全身显像,通过阅片和半定量分析图像,以手术或经胃镜活检病理及临床随访(>6个月)为确诊依据,评价PET/CT显像对胃癌的诊断价值及对临床治疗决策的影响。结果:81例患者中,胃癌51例,胃良性病变30例。18F-FDG PET/CT诊断胃癌的灵敏度、特异度和准确性分别为94.1%、83.3%和90.1%。对区域淋巴结转移的灵敏度和特异度分别为82.3%和82.4%。21例患者存在腹腔及其他部位转移,PET/CT显像的灵敏度为61.9%(13/21)。8例(15.7%,8/51)胃癌患者显像后更改了治疗方案。结论:18F-FDG PET/CT对胃癌治疗前的诊断具有重要的临床意义,对制定治疗方案有一定的指导价值。     

Improved medical image fusion based on cascaded PCA and shift invariant wavelet transforms

Purpose

In the medical field, radiologists need more informative and high-quality medical images to diagnose diseases. Image fusion plays a vital role in the field of biomedical image analysis. It aims to integrate the complementary information from multimodal images, producing a new composite image which is expected to be more informative for visual perception than any of the individual input images. The main objective of this paper is to improve the information, to preserve the edges and to enhance the quality of the fused image using cascaded principal component analysis (PCA) and shift invariant wavelet transforms.

Methods

A novel image fusion technique based on cascaded PCA and shift invariant wavelet transforms is proposed in this paper. PCA in spatial domain extracts relevant information from the large dataset based on eigenvalue decomposition, and the wavelet transform operating in the complex domain with shift invariant properties brings out more directional and phase details of the image. The significance of maximum fusion rule applied in dual-tree complex wavelet transform domain enhances the average information and morphological details.

Results

The input images of the human brain of two different modalities (MRI and CT) are collected from whole brain atlas data distributed by Harvard University. Both MRI and CT images are fused using cascaded PCA and shift invariant wavelet transform method. The proposed method is evaluated based on three main key factors, namely structure preservation, edge preservation, contrast preservation. The experimental results and comparison with other existing fusion methods show the superior performance of the proposed image fusion framework in terms of visual and quantitative evaluations.

Conclusion

In this paper, a complex wavelet-based image fusion has been discussed. The experimental results demonstrate that the proposed method enhances the directional features as well as fine edge details. Also, it reduces the redundant details, artifacts, distortions.

     

68Ga-成纤维细胞激活蛋白抑制剂PET/CT显像指南

⁶⁸Ga-成纤维细胞激活蛋白抑制剂（FAPI） PET/CT用于各种肿瘤性疾病、感染、炎症性疾病诊治中,均涉及适应证、医务人员岗位职责、操作规范（包括病史采集、患者准备和检查注意事项、放射性药物制备、图像采集和图像分析）、报告、质量控制和显像过程中的辐射安全问题。本指南旨在为临床顺利开展⁶⁸Ga-FAPI PET/CT检查,并在诊断报告中合理解释及标准化描述⁶⁸Ga-FAPI PET/CT所见提供依据。     

基于局部特征的医学图像融合方法

目的 介绍一种基于局部小波系数特征的多尺度医学图像融合方法.方法 首先对待融合的两幅医学图像做多尺度的小波分解,然后采用原始图像灰度的局部标准差作为小波系数选取的参考标准,最后再对选取的小波系数进行重构得到最终的融合图像.结果 成功将一幅MRI解剖图像和一幅SPECT功能图像融合在一起.结论 基于局部特征的医学图像融合方法是切实可行的,且简便灵活,图像融合效果较好.     

基于Contourlet的医学图像融合技术探讨

针对不同医学影像设备获得的多源图像信息有效融合和综合利用的问题,提出一种基于Contourlet区域特性的医学图像融合算法——CRSIF算法,借助于Contourlet变换的优良特性,在Contourlet变换域使用加权平均和选择方式实现频域系数的有效融合,对低频子带采用局部加权能量作为评价标准,高频子带采用区域加权Contourlet对比度的树型结构设计,以满足区域的融合规则。对CT/MR脑部医学图像的仿真分析表明,该算法可克服传统规则下融合图像不连续及产生毛刺和斑点的缺陷,使融合图像与人类视觉系统的感知特性相吻合。     

PET/CT融合图像诊断甲状腺癌——与CT、SPECT或PET的比较研究

目的通过与CT、SPECT或PET的对比研究,探讨PET/CT诊断甲状腺癌的价值.方法收集经随访、手术或活检、病理证实的甲状腺癌12例,CT检查12例,SPECT检查5例,PET检查7例,PET/CT检查12例,分别观察、记录病灶数目、位置、大小、核素分布、钙化等.结果12例共有病灶19个,CT显示病灶13个,SPECT静态显像发现病灶6个,灌注显像全部病灶血流灌注增加,PET发现放射性浓聚影9个,PET/CT见到异常高代谢区19个.结论CT图像能清晰显示病变形态、密度;核医学图像可提供病灶代谢信息;PET/CT图像可同时观察病灶解剖与功能信息,提高了定位、定性诊断能力.     

Positron emission tomography versus positron emission tomography/computed tomography: from "unclear" to "new-clear" medicine.

PET/CT is a new diagnostic imaging modality, which proves that adding PET and CT is not merely additive, but highly synergistic. While PET provides high sensitivity for lesion detection, CT provides the anatomic backdrop, which frequently is important in order to make a specific diagnosis. CT can, however, also add sensitivity to PET, as certain lesions such as small clearly pathological lung nodules may not at all be visualized on PET alone; and PET clearly adds specificity to CT because, e.g., indeterminate lymph nodes seen on CT can often be diagnosed unequivocally as benign or malignant, using PET information. Furthermore, attenuation correction of PET data, which is needed for best PET image quality, can also be obtained using the same CT data. Hence, PET/CT also provides a very fast solution for obtaining attenuation images. The major clinical applications of PET/CT are in tumor imaging of the body and the search for inflammatory foci, while for brain imaging, PET/CT is less relevant. In the brain, post acquisition fusion of PET and MRI data is relatively easy, while post acquisition fusion of PET and CT or MR data in the body is unreliable and cumbersome. We strongly feel that PET/CT is the oncological staging "one-stop-shop" examination of the future for many tumors. The key question in the next few years will be how much CT is needed in PET/CT for which clinical question? The advent of ever faster CT scanners suggests that PET/CT eventually may also provide a tool for a cardiac "one-stop-shop." So the future of PET/CT indeed looks bright.     

Clinical Value of Combined Positron Emission Tomography/Computed Tomography Imaging in the Interpretation of 2-Deoxy-2-[F-18]fluoro-<Emphasis Type="SmallCaps">d</Emphasis>-glucose–Positron Emission Tomography Studies in Cancer Patients

Background Positron emission tomography (PET)/computed tomography (CT) is a new imaging modality that provides exact coregistration of anatomic and metabolic data. We have investigated to what degree this new technique might affect the interpretation of PET images in a nonselected group of consecutive cancer patients, reflecting routine condition in a busy cancer center.Methods Whole-body 2-deoxy-2-[F-18]fluoro-d-glucose (FDG)–PET and PET/CT fusion image sets were compared in 100 consecutive, nonselected patients: 21 with head and neck cancer, 39 with chest malignancies, and 40 with malignancies of the abdomen and pelvis. All studies were performed for primary staging or evaluation of therapy and were interpreted by two nuclear medicine physicians also trained in radiology. Areas of abnormal FDG uptake were identified on PET and graded as likely benign, equivocal, or likely malignant. Positron emission tomography/computed tomography fusion images were then made available, and the initial findings were amended if necessary.Results One hundred sixty-six areas with abnormal FDG uptake were identified. Based on PET alone, 51 sites were considered equivocal for malignancy. With PET/CT, the number of equivocal lesions decreased to 24. This difference is more marked in the head and neck as well as the abdomen and pelvis. When the equivocal sites were included in the analysis and grouped with the malignant sites, positive predictive value (PPV) of PET/CT was 89% compared with 75% for PET (p = 0.04).Conclusion Combined PET/CT results in increased reader confidence and 53% fewer equivocal readings, as well as improved PPV compared with PET alone.*Contributed equally to this work.     

对比分析头颈部鳞状细胞癌PET/CT与PET/MR特征

目的 探讨头颈部鳞状细胞癌（HNSCC）的PET/CT及PET/MR特征。方法 纳入未经抗肿瘤治疗的头颈部鳞状细胞癌患者40例,所有患者均接受PET/CT及头颈部MR检查。由2名观察者独立观察PET阳性病灶,包括阳性原发灶及阳性淋巴结;并对PET/CT、PET/MR T1WI及PET/MR T2WI的图像质量、融合准确度、病灶清晰度、病灶特征等进行评分。分析2名观察者间的一致性。结果 40例患者共90个PET阳性病灶,包括阳性原发灶40个、阳性淋巴结50个。PET/CT、PET/MR T1WI及PET/MR T2WI在图像质量及融合准确度方面差异均无统计学意义（P均>0.05）;在显示阳性原发灶及阳性淋巴结的清晰度方面,PET/MR T1WI及PET/MR T2WI均优于PET/CT（P均<0.05）。40个阳性原发灶中,PET/MR T2WI对29个原发灶的特征显示多于PET/CT,4个原发灶与PET/CT相仿,7个原发灶较PET/CT少。结论 PET/MR在HNSCC诊断中的应用是可行的,在显示头颈部局部病灶时较PET/CT更具优势。     

Functional and structural synergy for resolution recovery and partial volume correction in brain PET

Purpose: Positron Emission Tomography (PET) has the unique capability of measuring brain function but its clinical potential is affected by low resolution and lack of morphological detail. Here we propose and evaluate a wavelet synergistic approach that combines functional and structural information from a number of sources (CT, MRI and anatomical probabilistic atlases) for the accurate quantitative recovery of radioactivity concentration in PET images. When the method is combined with anatomical probabilistic atlases, the outcome is a functional volume corrected for partial volume effects.Methods: The proposed method is based on the multiresolution property of the wavelet transform. First, the target PET image and the corresponding anatomical image (CT/MRI/atlas-based segmented MRI) are decomposed into several resolution elements. Secondly, high-resolution components of the PET image are replaced, in part, with those of the anatomical image after appropriate scaling. The amount of structural input is weighted by the relative high frequency signal content of the two modalities. The method was validated on a digital Zubal phantom and clinical data to evaluate its quantitative potential.Results: Simulation studies showed the expected relationship between functional recovery and the amount of correct structural detail provided, with perfect recovery achieved when true images were used as anatomical reference. The use of T1-MRI images brought significant improvements in PET image resolution. However improvements were maximized when atlas-based segmented images as anatomical references were used; these results were replicated in clinical data sets.Conclusion: The synergistic use of functional and structural data, and the incorporation of anatomical probabilistic information in particular, generates morphologically corrected PET images of exquisite quality.