Rapid calculation of detectability in Bayesian single photon emission computed tomography

We consider the calculation of lesion detectability using a mathematical model observer, the channelized Hotelling observer (CHO), in a signal-known-exactly/background-known-exactly detection task for single photon emission computed tomography (SPECT). We focus on SPECT images reconstructed with Bayesian maximum a posteriori methods. While model observers are designed to replace time-consuming studies using human observers, the calculation of CHO detectability is usually accomplished using a large number of sample images, which is still time consuming. We develop theoretical expressions for a measure of detectability, the signal-to-noise-ratio (SNR) of a CHO observer, that can be very rapidly evaluated. Key to our expressions are approximations to the reconstructed image covariance. In these approximations, we use methods developed in the PET literature, but modify them to reflect the different nature of attenuation and distance-dependent blur in SPECT. We validate our expressions with Monte Carlo methods. We show that reasonably accurate estimates of the SNR can be obtained at a computational expense equivalent to approximately two projection operations, and that evaluating SNR for subsequent lesion locations requires negligible additional computation.     

99Tcm-MIBI SPECT脑显像与MRI对脑胶质瘤术后残留的与复发的对比研究

目的 探讨99Tcm—MIBI SPECT脑显像与MRI对脑胶质瘤术后残留与复发的影像特征，并客观评价两种检查方法的优缺点及诊断价值。方法 对15例正常对照者，27例脑胶质瘤术后患者（其中术后残留7例，术后复发9例，无复发者11例）行99Tcm-MIBISPECT脑显像并同时行MRI显像．对其影像学特征进行分析比较。结果正常对照者。99Tcm-MIBI SPECT显像脑实质内无核素浓聚，MRI显像未见明显异常。胶质瘤术后组（7倒残留厦9倒复发者）99Tcm-MIBI SPECT脑显像均表现为核素浓聚，其它11例无复发者表现为无核素浓聚，MRI显像表现为真阳性者8例、真阴性者7例。假阳性者4例。假阴性者8例。99Tcm-MIBI SPECT脑显像诊断胶质瘤术后残留与复发的灵敏度、准确性和特异性分别为93，7％、96．3％和100％，MR分别为31.3％、44.4％和63．6％，两者比较灵敏度、准确性有差异（P〈0．05），特异性无差异（P〉0.05）。结论 99Tcm—MIBI SPECT、脑显像对早期发现胶质瘤残留覆术后复发比MRI更优越；对分析确定胶质瘤术后残留与复发的早期诊断与治疗具有重要价值。     

BP神经网络在肝癌数字减影血管造影诊断中的应用

目的 探讨利用BP神经网络对肝癌数字减影血管造影(DSA)图像进行计算机辅助诊断的应用价值.方法 分析32例肝癌病例DSA影像资料,应用BP神经网络建立计算机临床辅助诊断模型,然后把100个随机抽样测试样本(非病灶样本55个,病灶样本45个)输入模型验证诊断准确率.结果 肝癌计算机辅助诊断模型成功建立,100个随机抽样样本经模型分析,真阳性率为91%,真阴性率95%.结论 BP神经网络可应用于临床辅助肝癌DSA诊断.     

Diagnostic value of SPECT, PET and PET/CT in the diagnosis of coronary artery disease: A systematic review

Purpose:

The purpose of the study was to investigate the diagnostic value of SPECT, PET and PET/CT in the diagnosis of coronary artery disease, based on a systematic review.

Material and Methods:

A search of PubMed/Medline and Sciencedirect databases in the English-language literature published over the last 24 years was performed. Only studies with at least 10 patients comparing SPECT, PET or combined PET/CT with invasive coronary angiography in the diagnosis of coronary artery disease (50% stenosis) were included for analysis. Sensitivities and specificities estimates pooled across studies were analysed using a Chi-square test.

Results:

Twenty-five studies met the selection criteria and were included for the analysis. Ten studies were performed with SPECT alone; while another six studies were performed with PET alone. Five studies were carried out with both PET and SPECT modalities, and the remaining four studies were investigated with integrated PET-CT. The mean value of sensitivity, specificity and accuracy of these imaging modalities for the diagnosis of coronary artery disease was 82% (95%CI: 76 to 88), 76% (95%CI: 70 to 82) and 83% (95%CI: 77 to 89) for SPECT; 91% (95%CI: 85 to 97), 89% (95%CI: 83 to 95) and 89% (95%CI: 83 to 95) for PET; and 85% (95%CI: 79 to 90), 83% (95%CI: 77 to 89) and 88% (95%CI: 82 to 94) for PET/CT, respectively. The diagnostic accuracy of these imaging modalities was dependent on the radiotracers used in these studies, with ammonia resulting in the highest diagnostic value.

Conclusion:

Our review shows that PET has high diagnostic value for diagnosing coronary artery disease, and this indicates that it is a valuable technique for both detection and prediction of coronary artery disease.     

Diagnostic value of circulating microRNAs for osteosarcoma in Asian populations: a meta-analysis

A large number of studies have provided new insights into the diagnostic value of circulating microRNAs (miRNA) for osteosarcoma (OS), one of the most common primary malignancies in adolescents. However, inconsistent conclusions on the diagnostic performance of various kinds of miRNAs have been made. To assess the true diagnostic value of circulating miRNA for the early detection of OS in this meta-analysis, multiple databases, including PubMed, EMBASE, Web of Science, Chinese National Knowledge Infrastructure (CNKI), and Technology of Chongqing (VIP), were carefully searched for available studies up to October 30, 2015. The quality of each study was scored using the quality assessment of diagnostic accuracy studies-2 (QUADAS-2). Sensitivity and specificity was pooled using a random-effects model. Positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and the area under the curve (AUC) were used to measure the diagnostic values. Subgroup and meta-regression analyses were used to find potential sources of heterogeneity. Publication bias was tested with the Deeks’ funnel plot asymmetry test. Eight articles with 741 OS patients and 479 healthy controls were finally included in this meta-analysis. The pooled estimations indicated circulating miRNAs has a high accuracy for diagnosing OS, with sensitivity of 0.94, specificity of 0.80, PLR of 4.75, NLR of 0.07, DOR of 69, and AUC of 0.94. In addition, subgroup and meta-regression analyses revealed that the expression patterns of miRNAs obtained from plasma are more credible diagnostic biomarkers than those from serum. In conclusion, as noninvasive biomarkers, circulating miRNAs have a promising future for the diagnosis of OS in Asian populations.     

液基薄层细胞学结合阴道镜检查在宫颈病变筛查中的临床意义

目的探讨宫颈液基薄层细胞学(TCT)结合阴道镜检查在宫颈病变筛查中的临床意义。方法对854例已婚妇女进行宫颈液基薄层细胞学检测,对宫颈细胞学异常者行阴道镜检查及活组织检查。结果 854例TCT检测的患者中,宫颈病变发生率达81.9%,其中良性病变482例,占69%,宫颈上皮内病变217例,占25.4%,对217例宫颈细胞学异常者进行阴道镜下活检与组织病理学诊断比较,符合率为88.7%。宫颈上皮内病变高发年龄为30-40岁,占35.5%。结论 TCT技术在宫颈病变的诊断中,具有简便、实用,准确率高的特点,配合阴道镜检查能及时发现宫颈早期病变,是防止宫颈癌的关键。     

Imaging markers of mild cognitive impairment: multivariate analysis of CBF SPECT

This study aimed to investigate cross-sectional and longitudinal changes of regional cerebral blood flow (rCBF) in preclinical dementia using single photon emission computed tomography (SPECT). SPECT and cognitive function were investigated in 39 mild cognitive impairment (MCI) subjects and 20 age-matched controls. All subjects were followed longitudinally 19 months on average, 16 MCI subjects progressed to Alzheimer's disease (AD), who were retrospectively defined as progressive mild cognitive impairment (PMCI) at baseline and 23 MCI subjects remained stable and were defined as stable mild cognitive impairment (SMCI) at baseline. SPECT was performed both at the initial investigation and at follow-up. Image data were analyzed using multivariate analysis, SPM and volume of interest (VOI)-based analysis. Significant covariate patterns were derived, which differentiate among PMCI, SMCI and controls at baseline as well as describe the longitudinal progression of PMCI. The combined SPECT and neuropsychology increased the diagnostic accuracy of PMCI at baseline. SPECT and neuropsychological testing can be used objectively for both baseline diagnosis and to monitor changes in brain function during very early AD.     

Evaluation of thyroid fine‐needle aspirations: Can ThinPrep be used exclusively to appropriately triage patients having a thyroid nodule?

Thyroid fine-needle aspiration (FNA) represents an ideal management tool for thyroid nodules. ThinPrep is routinely used in preparation of a variety of nongynecologic cytology specimens, including FNA. The authors investigated ThinPrep to determine if its diagnostic accuracy is sufficient to triage patients presenting with a thyroid nodule. ThinPrep (TP) slides from four separate study categories were reviewed in a blind fashion. Twenty-five cases of papillary carcinoma, follicular lesion, Hashimoto's thyroiditis and multinodular goiter were examined retrospectively. Diagnostic accuracy of TP for each diagnostic category was determined relative to the final FNA diagnosis. Of 100 total study cases, 46 (46%) had noncorrelation. Twenty five (25%) of the study cases had noncorrelation as a result of insufficient cellularity. The diagnostic accuracy of TP for papillary carcinoma was 64%, for follicular lesion 24%, for Hashimoto's thyroiditis 72% and for multinodular goiter 56%. Cytologic features of papillary carcinoma, Hashimoto's thryoiditis, and multinodular goiter are preserved in TP slides. Cytologic features of follicular lesion are less predictable in TP slides. When all cases of noncorrelation were examined, we concluded that insufficient or marginal cellularity most often accounts for the discrepancy between TP and CS diagnoses in each study category. If techniques can be established to improve cellularity of TP slides, particularly in follicular lesions, we believe that sufficient diagnostic accuracy can be achieved to result in appropriate patient triage. Additional studies exploring methods to improve TP cellularity are needed before TP can be used as the sole diagnostic test for thyroid FNA.     

SPECT与低剂量CT融合显像在颅骨病变良恶性鉴别诊断中的价值

为评价SPECT与低剂量CT融合显像在鉴别颅骨良、恶性病变中的临床应用价值,选取伴颅骨病变的骨外原发肿瘤患者81例（118个病灶）,所有患者均行全身平面骨显像,其中25例（40个病灶）行颅骨SPECT显像,43例（66个病灶）行头部异机CT或MR I显像,12例（19个病灶）行颅骨SPECT与低剂量CT融合显像。所有图像均由至少两名医师判读,判读结果与最后诊断符合者,为＂符合＂。计算并比较各种方法在鉴别颅骨病变中的符合率。各种方法在良/恶性病灶诊断符合率及总符合率上均有显著性差异,其中SPECT与低剂量CT融合显像的总符合率优于其他方法。在判定良性病灶时,SPECT与低剂量CT融合显像与其他方法之间均有显著性差异,符合率优于其他方法;在判定恶性病灶时,SPECT与低剂量CT融合显像与全身骨显像、骨SPECT显像存在显著性差异,符合率优于二者。SPECT与低剂量CT融合骨显像在鉴别诊断颅骨良恶性病变中具有较好的临床应用价值。     

Diagnostic accuracy of fecal lactoferrin for inflammatory bowel disease: a meta-analysis

Objective: To do a systematic review using meta-analysis to assess the diagnostic accuracy of fecal lactoferrin (FL) in patients with inflammatory bowel disease (IBD). Methods: We performed a literature review and systematically searched the Medline and EMBASE databases for eligible studies. The quality of the included studies was assessed using the QUADAS tool. The sensitivity, specificity, and other diagnostic indexes of FL were pooled using a random-effects model. Results: Seven studies, involving 1816 patients, met the inclusion criteria. In all studies, the pooled FL sensitivity and pooled specificity were 0.82 (95% confidence interval [CI]: 0.72, 0.89) and 0.95 (95% CI: 0.88, 0.98), respectively. The positive and negative likelihood ratios were 16.63 and 0.18, respectively. The area under the summary receiver-operating characteristic curve (SROC) was 0.95 (95% CI: 0.93, 0.97), and the diagnostic odds ratio was 90.04 (95% CI: 37.01, 219.02). The pooled FL sensitivity and specificity for Crohn’s disease (CD) diagnosis (sensitivity =75%, specificity =100%) was not as good as it was for ulcerative colitis (UC) diagnosis (sensitivity =82%, specificity =100%). Conclusion: FL, as a noninvasive and screening marker, has a high specificity and a modest specificity during the diagnosis of suspected IBD.     

Effect of clinical history on diagnostic accuracy in the cytologic interpretation of bronchial brush specimens

There has been little study of the effect of clinical history on pathologic diagnostic accuracy. Five pathologists retrospectively examined 97 bronchial brush specimens with and without clinical historic information. Forty-nine patients had a biopsy-proven malignant lesion, and 48 had a benign lesion. Diagnostic accuracy with and without history for each pathologist was determined with likelihood ratios and receiver operating characteristic curves. The overall diagnostic accuracy with and without history was 0.84 and 0.76, respectively. The average negative predictive value of a benign diagnosis decreased from 89.2% (with history) to 74.0% (without history). Overall, the cytopathologists were more reluctant to make a definitive malignant diagnosis without history compared with history. The average positive predictive value of a malignant diagnosis with and without history was almost identical. The absence of history leads to lower diagnostic accuracy in the cytologic interpretation of bronchial brush specimens partly because pathologists underdiagnose malignant lesions.     

In vivo 1H MRS for musculoskeletal lesion characterization: which factors affect diagnostic accuracy?

In vivo ¹H MRS is a noninvasive imaging technique for the identification of malignancy. Musculoskeletal lesions vary in their composition, causing field inhomogeneity and magnetic susceptibility effects which may be technical and diagnostic challenges for MRS. This study investigated the factors that affect diagnostic accuracy in the use of MRS for the characterization of musculoskeletal neoplasms. During a 7‐year period, 210 consecutive patients with musculoskeletal lesions larger than 1.5 cm in diameter were examined. MRS of a single‐voxel point‐resolved spectroscopy sequence with TE = 135 ms was undertaken using a 1.5‐T scanner. Lesions with a choline signal‐to‐noise ratio larger than 3.0 were considered to be malignant tumors. The diagnostic accuracy was calculated for all lesions and for subgroups on the basis of lesion type (bone and soft tissue), lesion composition (mixed and solid nonsclerotic), lesion size (≤4, >4–10 and >10 cm), MR scanner (MR scanner 1 and 2) and selected voxel size (≤3, >3–8 and >8 cm³). Multivariate logistic regressions were performed to estimate the associations between each factor and diagnostic accuracy. The diagnostic accuracy was 73.3% for all lesions. The accuracy was 54.4% for mixed lesions and 80.4% for solid nonsclerotic lesions (p < 0.001). The diagnostic accuracy was lower for larger lesions [86.8% for lesions of ≤4 cm, 71.6% for lesions of >4–10 cm (p = 0.04) and 63.6% for lesions of >10 cm (p = 0.007)]. There was no difference in diagnostic accuracy for bone versus soft‐tissue lesions or as a function of MR scanner or voxel size. By the use of multivariate logistic regression, a solid nonsclerotic lesion was 3.15 times (95% confidence interval, 1.59–6.27) more likely than a mixed lesion to have a diagnosis (p = 0.001). MRS can be used to characterize musculoskeletal lesions, particularly solid nonsclerotic lesions. Copyright © 2011 John Wiley & Sons, Ltd.     

SPECT/CT融合显像在分化型甲状腺癌转移灶诊断中的应用价值分析

目的 探讨SPECT/CT 131I显像在诊断分化型甲状腺癌转移灶中,以及在131I放射治疗后复发和转移中的应用价值,为临床诊断和治疗甲状腺癌提供依据.方法 选择2013年5月至2016年5月我院住院治疗经病理证实的分化型甲状腺癌住院患者90例,分别实施131I-WBS,131I-SPECT/CT显像诊断,观察显像诊断结果以及Tg水平.结果 131 I-WBS共诊断出125个复发和转移病灶,其中113个经病理检查证实,其诊断灵敏度和准确度分别为85.03％,78.62％:131I-SPECT/CT共诊断出134个复发和转移病灶,其中128个经病理检查证实,其诊断灵敏度和准确度分别为91.16％,87.58％;说明131I-SPECT诊断的灵敏度要优于131 I-WBS显像,两组数据比较差异有统计学意义(P＜0.05);此外131I-WBS显像、131I-SPECT/CT显像阳性的Tg水平与阴性患者比较明显升高,且差异有统计学意义(P＜0.05).结论 SPECT/CT显像在诊断分化型甲状腺癌转移灶方面具有重要价值,值得临床广泛的应用.     

Investigation of dynamic SPECT measurements of the arterial input function in human subjects using simulation, phantom and human studies

Computer simulations, a phantom study and a human study were performed to determine whether a slowly rotating single-photon computed emission tomography (SPECT) system could provide accurate arterial input functions for quantification of myocardial perfusion imaging using kinetic models. The errors induced by data inconsistency associated with imaging with slow camera rotation during tracer injection were evaluated with an approach called SPECT/P (dynamic SPECT from positron emission tomography (PET)) and SPECT/D (dynamic SPECT from database of SPECT phantom projections). SPECT/P simulated SPECT-like dynamic projections using reprojections of reconstructed dynamic (94)Tc-methoxyisobutylisonitrile ((94)Tc-MIBI) PET images acquired in three human subjects (1 min infusion). This approach was used to evaluate the accuracy of estimating myocardial wash-in rate parameters K(1) for rotation speeds providing 180° of projection data every 27 or 54 s. Blood input and myocardium tissue time-activity curves (TACs) were estimated using spatiotemporal splines. These were fit to a one-compartment perfusion model to obtain wash-in rate parameters K(1). For the second method (SPECT/D), an anthropomorphic cardiac torso phantom was used to create real SPECT dynamic projection data of a tracer distribution derived from (94)Tc-MIBI PET scans in the blood pool, myocardium, liver and background. This method introduced attenuation, collimation and scatter into the modeling of dynamic SPECT projections. Both approaches were used to evaluate the accuracy of estimating myocardial wash-in parameters for rotation speeds providing 180° of projection data every 27 and 54 s. Dynamic cardiac SPECT was also performed in a human subject at rest using a hybrid SPECT/CT scanner. Dynamic measurements of (99m)Tc-tetrofosmin in the myocardium were obtained using an infusion time of 2 min. Blood input, myocardium tissue and liver TACs were estimated using the same spatiotemporal splines. The spatiotemporal maximum-likelihood expectation-maximization (4D ML-EM) reconstructions gave more accurate reconstructions than did standard frame-by-frame static 3D ML-EM reconstructions. The SPECT/P results showed that 4D ML-EM reconstruction gave higher and more accurate estimates of K(1) than did 3D ML-EM, yielding anywhere from a 44% underestimation to 24% overestimation for the three patients. The SPECT/D results showed that 4D ML-EM reconstruction gave an overestimation of 28% and 3D ML-EM gave an underestimation of 1% for K(1). For the patient study the 4D ML-EM reconstruction provided continuous images as a function of time of the concentration in both ventricular cavities and myocardium during the 2 min infusion. It is demonstrated that a 2 min infusion with a two-headed SPECT system rotating 180° every 54 s can produce measurements of blood pool and myocardial TACs, though the SPECT simulation studies showed that one must sample at least every 30 s to capture a 1 min infusion input function.     

4D maximum a posteriori reconstruction in dynamic SPECT using a compartmental model-based prior

A 4D ordered-subsets maximum a posteriori (OSMAP) algorithm for dynamic SPECT is described which uses a temporal prior that constrains each voxel's behaviour in time to conform to a compartmental model. No a priori limitations on kinetic parameters are applied; rather, the parameter estimates evolve as the algorithm iterates to a solution. The estimated parameters and time-activity curves are used within the reconstruction algorithm to model changes in the activity distribution as the camera rotates, avoiding artefacts due to inconsistencies of data between projection views. This potentially allows for fewer, longer-duration scans to be used and may have implications for noise reduction. The algorithm was evaluated qualitatively using dynamic 99mTc-teboroxime SPECT scans in two patients, and quantitatively using a series of simulated phantom experiments. The OSMAP algorithm resulted in images with better myocardial uniformity and definition, gave time-activity curves with reduced noise variations, and provided wash-in parameter estimates with better accuracy and lower statistical uncertainty than those obtained from conventional ordered-subsets expectation-maximization (OSEM) processing followed by compartmental modelling. The new algorithm effectively removed the bias in k21 estimates due to inconsistent projections for sampling schedules as slow as 60 s per timeframe, but no improvement in wash-out parameter estimates was observed in this work. The proposed dynamic OSMAP algorithm provides a flexible framework which may benefit a variety of dynamic tomographic imaging applications.     

血清胱抑素C对糖尿病肾病诊断价值的Meta分析

目的评价血清胱抑素C在诊断糖尿病肾病中的价值。方法检索多个数据库,对相关文献进行系统评价,用随机效应模型计算纳入研究的总灵敏度、特异度及其它指标,绘制受试者工作特征曲线以探讨本试验的总体诊断特性。结果按照选择标准最终有9项独立研究纳入本次meta分析,合并灵敏度与特异度分别为85%和86%,合并阳性拟然比与阴性拟然比分别为6.23和0.17,合并诊断优势比为54.59,SROC曲线下面积0.9435,SE为0.0273。结论血清胱抑素C水平的检测有助于评估肾小球滤过功能,对糖尿病肾病患者早期肾损害有一定的诊断价值。     

Biological equivalent dose prediction in pion irradiation using pion star density and the mixed beam lesion additivity model

The biological equivalent dose profile of the pion beam was predicted with one parameter (gamma) using physical dose and pion star density. The value of the relative biological effectiveness (RBE) at each depth was given as a linear function of pion star density (PSD): RBE = 1.0 + gamma PSD, assuming (i) the mixed beam lesion additivity model and (ii) the linear relationship between the ratio of high LET dose to total dose and pion star density. The predicted depth-survival curve fitted well with the pooled biological data of the gel technique using Chinese hamster cells (CHO). The predicted RBE were consistent with previously published results through the flat dose peak, except at the decreasing portion of the dose profile. The practical usefulness of this model in clinical treatment is stressed.     

99Tcm-奥曲肽SPECT/CT对肺癌的诊断价值

目的 探讨锝(99Tcm)标记的生长抑素类似物奥曲肽(99Tcm-Octreotide)SPECT/CT对肺癌诊断的价值.方法 对疑诊为肺癌患者65例静脉注射99Tcm-Octreotide 740 MBq,4h后行胸部SPECT/CT.通过视觉阅片及肿瘤组织/正常肺组织(T/N)比值的半定量分析,分别对肺癌与良性占位...     

模糊BP神经网络在新生儿HIE早期诊断中的应用研究

为研究建立一种新生儿缺氧缺血性脑病(HIE)早期诊断辅助系统,提高临床诊断的客观性和准确性。本研究在多项相关研究的基础上,优选出15项诊断HIE早期、敏感性和特异性高的无创指标,对按常规标准诊断的140例HIE患儿数据进行模糊神经网络实验,初步验证结果显示所有训练样本的正确识别率为100%,所有测试样本的正确识别率为95%,误诊率为5%。证明该方法对早期诊断具有可行性和较高的准确性。基于临床综合指标的模糊BP神经网络所构成的诊断系统,为HIE临床早期诊断提供了一种客观、便捷的诊断新方法。