Illustrations cliniques en pneumologie (embolie pulmonaire)

The examples and clinical cases presented in this section are not intended to be considered as absolute models in terms of image quality or device parameter settings. They must initiate an individual analysis according to CT parameters and image quality. Nevertheless, they present practically different CT levels, which can be used according to the clinical context and the type of device.     

Illustrations cliniques en neurologie

The examples and clinical cases presented in this section are not intended to be considered as absolute models in terms of image quality or device parameter settings. They must initiate an individual analysis according to CT parameters and image quality. Nevertheless, they present practically different CT levels, which can be used according to the clinical context and the type of device.     

Should patients with an incidental finding of focal myocardial 18FDG uptake be screened by myocardial perfusion scintigraphy?

PurposeFocal F-18-fluoro-deoxy-glucose uptake in the myocardium can be a sign of resting myocardial ischemia. The purpose of our study was to assess the relevance of performing myocardial perfusion scintigraphy to screen for myocardial ischemia in patients with an incidental finding of focal myocardial F-18-fluoro-deoxy-glucose uptake on a routine F-18-fluoro-deoxy-glucose positron-emission-tomography-computed-tomography.MethodsIn our retrospective multicentric study, patients were included if they had had an incidental finding of myocardial focal F-18-fluoro-deoxy-glucose uptake on a routine F-18-fluoro-deoxy-glucose positron-emission-tomography-computed-tomography and had also undergone myocardial perfusion scintigraphy within 3 months before or after the F-18-fluoro-deoxy-glucose positron-emission-tomography-computed-tomography. Patients with a pattern of ischemia or scar on the myocardial perfusion scintigraphy in the same territory as the focal F-18-fluoro-deoxy-glucose uptake were considered positive.ResultsSeven of the 34 included patients were positive, with an abnormality on the MPS data in the same territory as the focal myocardial F-18-fluoro-deoxy-glucose uptake. 2 of the 6 patients with focal F-18-fluoro-deoxy-glucose uptake in the left anterior descending vascular supply territory and 2 of the 4 patients with focal F-18-fluoro-deoxy-glucose uptake in the standard right coronary artery territory had an abnormal myocardial perfusion scintigraphy. All 12 patients with focal F-18-fluoro-deoxy-glucose uptake restricted to the basal anterolateral and basal inferolateral segments were negative.ConclusionPatients with an incidental finding of focal F-18-fluoro-deoxy-glucose uptake on a routine F-18-fluoro-deoxy-glucose positron-emission-tomography-computed-tomography may be considered as being at risk for coronary artery disease, when this uptake is multisegmentary in the same typical coronary territory and not restricted to the basal anterolateral and basal inferolateral segments.     

Illustrations cliniques en oncologie

The examples and clinical cases presented in this section are not intended to be considered as absolute models in terms of image quality or device parameter settings. They must initiate an individual analysis according to CT parameters and image quality. Nevertheless, they present practically different CT levels, which can be used according to the clinical context and the type of device.     

Illustrations cliniques en pédiatrie

The examples and clinical cases presented in this section are not intended to be considered as absolute models in terms of image quality or device parameter settings. They must initiate an individual analysis according to CT parameters and image quality. Nevertheless, they present practically different CT levels which can be used according to the clinical context and the type of device.     

Illustrations cliniques en ostéo-articulaire

The examples and clinical cases presented in this section are not intended to be considered as absolute models in terms of image quality or device parameter settings. They must initiate an individual analysis according to CT parameters and image quality. Nevertheless, they present practically different CT levels, which can be used according to the clinical context and the type of device.     

Illustrations cliniques en endocrinologie

The examples and clinical cases presented in this section are not intended to be considered as absolute models in terms of image quality or device parameter settings. They must initiate an individual analysis according to CT parameters and image quality. Nevertheless, they present practically different CT levels, which can be used according to the clinical context and the type of device.     

Taux de fixation de la pointe du ventricule gauche et correction d’atténuation TEMP/TDM dans la scintigraphie myocardique de perfusion chez les patients non ischémiques

Introduction

Attenuation correction (AC) has been shown to improve the accuracy of myocardial perfusion single photon emission computed scintigraphy (SPECT). It often reveals a decrease in apical uptake in the AC of the left ventricular (LV) in non-ischemic patients. We aimed to identify the parameters that could affect the apical radiotracer uptake in non-ischemic patients.

Impact dosimétrique des gamma-caméras de nouvelle génération en cardiologie nucléaire

Myocardial perfusion scintigraphy (MPS) has a key role in early detection and prognosis assessment of coronary artery disease. Several recently published studies highlighted the potential future cancer risk associated with SMP, and the cumulative radiation dose over long periods of time due to MPS and additional procedures involving ionizing radiations. This article aims to present a synthesis of recent literature dealing with dosimetry in cardiac imaging procedures, and in particular MPS; to discuss available solutions to reduce as much as possible radiation exposure to patients by applying the principles of justification and optimization; and finally to present the experience of two centers on Nuclear Medicine (Centre Cardiologique du Nord, Saint-Denis and Hôpital Bichat, Paris) about the use of new generation SPECT cameras (CZT) and their impact on dosimetry reduction.     

A rapid protocol to evaluate coronary flow reserve with myocardial scintigraphy: A prospective study using Regadenoson

Cardiac positron emission tomography (PET) is superior to single-photon emission computed tomography (SPECT) thanks to its quantitative analysis capabilities, especially for measuring myocardial blood flow (MBF) and myocardial flow reserve (MFR). The recent development of new cadmium zinc telluride (CZT) gamma cameras has enabled dynamic acquisition, allowing measurement of MBF and MFR. This prospective study aimed to determine the fastest protocol, to analyse MBF and perfusion imaging.Methods and resultsFrom February to June 2018, 10 patients were referred to our centre and prospectively enrolled in our study to evaluate the MBF and MFR, with 5 different reconstruction list-mod. The primary endpoint was to assess the reproducibility of the different reconstruction, and time of acquisition. The secondary endpoint was the evaluation of the image quality of the MPI. The 6-min tests highlighted no significant difference in the flow measurement and MFR (P = 0,15). Differences become significant by decreasing acquisition time. The image quality did not differ significantly (P = 0.6).ConclusionWe determined a fast (12mn acquisition) reliable and reproducible protocol to evaluate MBF and MFR without any loss of MPI information.     

Exploration des polyalgies par la scintigraphie osseuse planaire couplée à la TEMP-TDM

Polyalgia are a frequent indication of bone scintigraphy. The diagnostic process consists in seeking the characteristic data of a pathology, clinical, biological and radiological data integration, aspect, number and location of the lesions on planar bone scintigraphy and often, accurate location and morphological aspect of each lesion on the single photon emission computerized tomography guided by computerized tomography (SPECT/CT). The various pathologies responsible for polyalgia are arbitrarily classified according to their peripheral, axial or mixed predominance and are briefly described.     

Comparative analysis of iterative reconstruction algorithms with resolution recovery and new solid state cameras dedicated to myocardial perfusion imaging

New technologies are available in myocardial perfusion imaging. They include new software that recovers image resolution and limits image noise, multifocal collimators and dedicated cardiac cameras in which solid-state detectors are used and all available detectors are constrained to imaging just the cardiac field of view.These innovations resulted in shortened study times or reduced administered activity to patients, while preserving image quality.Many single center and some multicenter studies have been published during the introduction of these innovations in the clinical practice. Most of these studies were lead in the framework of “agreement studies” between different methods of clinical measurement. They aimed to demonstrate that these new software/hardware solutions allow the acquisition of images with reduced acquisition time or administered activity with comparable results (as for image quality, image interpretation, perfusion defect quantification, left ventricular volumes and ejection fraction) to the standard-time or standard-dose SPECT acquired with a conventional gamma camera and reconstructed with the traditional FBP method, considered as the gold standard.The purpose of this review is to provide the reader with a comprehensive understanding of the pro and cons of the different approaches summarizing the achievements reached so far and the issues that need further investigations.     

缺血性心肌病的多模态心血管影像学方法进展

近年来,超声(ultrasound, US)、CT冠状动脉造影(CT coronary angiography, CCTA)、血管内超声(intravenous ultrasound,IVUS)、光学相干断层成像(optical coherence tomography, OCT)、多层螺旋CT成像(multi-slice computed tomography, MSCT)、单光子发射计算机断层成像(single-photon emission computed tomography, SPECT)、正电子发射计算机断层成像(positron emission computed tomography, PET)及心脏磁共振(cardiac magnetic resonance, CMR)等多种心血管成像技术能够提供与冠脉病变及心肌形态和功能相关的解剖学、血流动力学、细胞生物学及病理生理学等方面的重要信息,在缺血性心肌病的临床诊疗及预后评估中发挥着日益重要的作用。然而,如何恰当选择的多模态心血管影像技术是临床医师面临的一大难题。因此,本文在归纳总结主要心血管成像技术临床应用进展的基础上,对多模态心血管影像学在缺血性心肌病相关的冠脉解剖与斑块成像、心肌功能、心肌灌注及心肌活性显像中的临床应用价值进行综述。旨在帮助临床医师客观认识各种成像技术的优势与不足,从而制定最优化的选择方案。     

Scintigraphie myocardique et séquelles de myocardite : présentation d’un cas clinique

Acute and subacute myocarditis are well-defined pathological entities but it is often difficult to identify them because their clinical expression is variable and the diagnosis is histological showing myocardial inflammation associated with degeneration and/or necrosis. Often symptoms are similar to those of acute pericarditis with “chest-crushing” pain that mimics myocardial infarction and prompts practitioners to request angiography, especially when there are cardiovascular risk factors. We report the case of a 61-year-old patient with neither cardiac history nor cardiovascular risk factor who consulted for a long and self-limited atypical chest pain with normal clinical examination and electrocardiogram. Myocardial perfusion scintigraphy showed a non-reversible photopenic area suspected of being a nontransmural necrosis or an artifact. The discovery of inferolateral hypokinesis of left ventricle on echocardiography led to perform a coronary angiography which was finally normal. Cardiac MRI allowed to diagnose scars of a previous episode of myocarditis.     

VCTDSA联合CT灌注成像在急性缺血性卒中诊断运用探究

目的：探讨64层容积CT数字减影血管造影（Volume computed tomography digital subtraction angiography, VCTDSA）联合CT灌注成像在急性缺血性卒中诊断价值。方法：回顾性分析45例临床确诊为急性缺血性卒中患者的临床资料,分别给予VCTDSA与CT灌注成像处理,分析这两种技术对急性缺血性卒中患者的诊断敏感性和特异性。结果：45例患者检查有颅内有不同部位出血灶,多见于脑室,均伴有不同程度的异常血管网形成,其中VCTDSA图像质量优于CT灌注成像,VCTDSA较DSA可准确显示和测量动静脉瘘口大小,VCTDSA与MRA在瘤体长轴、瘤颈的比较中无显著性差异。结论：与其他减影CTA比较,VCTDSA联合CT灌注成像在急性缺血性卒中患者的诊断中具有优势。     

Small-animal imaging using clinical positron emission tomography/computed tomography and super-resolution

Considering the high cost of dedicated small-animal positron emission tomography/computed tomography (PET/CT), an acceptable alternative in many situations might be clinical PET/CT. However, spatial resolution and image quality are of concern. The utility of clinical PET/CT for small-animal research and image quality improvements from super-resolution (spatial subsampling) were investigated. National Electrical Manufacturers Association (NEMA) NU 4 phantom and mouse data were acquired with a clinical PET/CT scanner, as both conventional static and stepped scans. Static scans were reconstructed with and without point spread function (PSF) modeling. Stepped images were postprocessed with iterative deconvolution to produce super-resolution images. Image quality was markedly improved using the super-resolution technique, avoiding certain artifacts produced by PSF modeling. The 2 mm rod of the NU 4 phantom was visualized with high contrast, and the major structures of the mouse were well resolved. Although not a perfect substitute for a state-of-the-art small-animal PET/CT scanner, a clinical PET/CT scanner with super-resolution produces acceptable small-animal image quality for many preclinical research studies.     

Infection de prothèse vasculaire : TEP-FDG vs scintigraphie aux leucocytes marqués (planaires et TEMP/TDM)

Vascular prosthesis infection is an uncommon but life-threatening complication. Its diagnosis is difficult to establish especially due to the low specificity of computed tomography (CT). The aim of this preliminary study was to compare the diagnostic value of positron emission tomography with¹⁸FDG (¹⁸FDG-PET) and ^99mTc-HMPAO-labeled leukocytes scintigraphy in this indication. ¹⁸FDG-PET/CT and ^99mTc-HMPAO-labeled leukocytes scintigraphy (planar at 6th and 24th hours after injection + SPECT/CT at the 6th hour) were prospectively performed in 11 patients (total of 22 vascular prosthesis with 14 clinical suspicions of infection). Both scans were retrospectively and blindly assessed by two independent nuclear medicine physicians. Interpretation was based on visual analysis. The gold standard was bacteriology findings or clinical follow-up greater than 6 months. Eight prostheses were considered as infected. PET found eight true-positive and one false-positive. Scintigraphy found eight true-positive and no false-positive. A focal or heterogeneous FDG-uptake higher or equal than hepatic uptake was considered as positive in PET. A focal prosthetic activity, stable or increased at the 24th hour was considered as positive in labeled leukocyte scintigraphy. SPECT/CT gave accurate anatomic localization and differentiated clearly infections of soft tissues from those of prostheses. ¹⁸FDG-PET could be performed in first-line in suspicion of vascular prosthesis infection. In litigious cases, a^99mTc-HMPAO-labeled leukocytes scintigraphy in association with SPECT/CT could bring additional arguments for infection diagnosis.     

Adaptive Tensor-Based Principal Component Analysis for Low-Dose CT Image Denoising

Computed tomography (CT) has a revolutionized diagnostic radiology but involves large radiation doses that directly impact image quality. In this paper, we propose adaptive tensor-based principal component analysis (AT-PCA) algorithm for low-dose CT image denoising. Pixels in the image are presented by their nearby neighbors, and are modeled as a patch. Adaptive searching windows are calculated to find similar patches as training groups for further processing. Tensor-based PCA is used to obtain transformation matrices, and coefficients are sequentially shrunk by the linear minimum mean square error. Reconstructed patches are obtained, and a denoised image is finally achieved by aggregating all of these patches. The experimental results of the standard test image show that the best results are obtained with two denoising rounds according to six quantitative measures. For the experiment on the clinical images, the proposed AT-PCA method can suppress the noise, enhance the edge, and improve the image quality more effectively than NLM and KSVD denoising methods.     

Scintigraphie pulmonaire pour suspicion d’embolie pulmonaire aiguë : état des lieux des pratiques en France en 2014

AimThe aim of this study was to assess lung scintigraphy practices in France for the diagnosis of acute pulmonary embolism, especially regarding the proportion of centers using single photon emission computed tomography (SPECT) rather than planar ventilation/perfusion (V/Q) imaging.Materials and methodsAn online survey composed of simple multiple-choice questions was distributed to the 210 french nuclear medicine departments in April and May 2014. The survey covered image acquisition, interpretation criteria for SPECT and planar images, and use of pseudoplanar images and radiopharmaceuticals. Departments were initially solicited by 2 sets of e-mails. They were subsequently contacted by phone. A single response per department was consolidated.ResultsTwo hundred nine responses were collected (participation rate: 99.5%). Sixty-seven percent of french centers indicated use of V/Q SPECT in routine practice. The first intention acquisition protocol was SPECT/CT in 34%, SPECT in 26% and V/Q planar in 34%. The most commonly used criteria for SPECT interpretation were those of the EANM (63%). Criteria used for planar interpretation were heterogeneous (EANM criteria, 39%; no standardized criteria, 28%; PIOPED, 23%). Eighty-three percent of centers used ^99mTc aerosol and 17% ^81mKr.ConclusionThis survey shows that SPECT has largely replaced planar imaging for PE diagnosis with lung scintigraphy. Acquisition protocols and interpretation criteria are inconsistent (especially for planar imaging).     

Simultaneous achievement of accurate CT number and image quality improvement for myocardial perfusion CT at 320-MDCT volume scanning

PurposeTo investigate differences in image-to-image variations between full- and half-scan reconstruction on myocardial CT perfusion (CTP) study.MethodsUsing a cardiac phantom we performed ECG-gated myocardial CTP on a second-generation 320-multidetector CT volume scanner. The heart rate was set at 60 bpm; once per second for a total of 24 s were performed. CT images were acquired at 80- and 120 kVp and subjected to full- and half-scan reconstruction. On images acquired at the same slice level we then measured image-to-image variations, coefficients of variance (CV), and image noise.ResultsThe image-to-image variations with full- and half-scan reconstruction were 1.3 HU vs. 27.2 HU at 80 kVp (p < 0.001) and 0.70 HU vs. 9.3 HU at 120 kVp (p < 0.001) even though the mean HU value was almost the same for both reconstruction methods. The CV of 80- and 120-kVp images of the left ventricular cavity decreased by 0.16% and 0.17%, respectively, with full-scan reconstruction; with half-scan reconstruction it decreased by 3.34% and 2.30%, respectively. Compared with half-scan reconstruction, the image noise was reduced by 27.2% at 80 kVp and by 28.0% at 120 kVp with full-scan reconstruction.ConclusionMyocardial CTP with full-scan reconstruction substantially decreased image-to-image variations and provided accurate CT attenuation.