0171: Identification of complicated carotid plaques by adding functional fluorodeoxyglucose-positron emission tomographic imaging to morphological characteristics on computed tomographic angiography

AimWe developed a simple semi-quantitative score for the analysis of carotid plaques with FDG-PET-CTA imaging and tested whether adding functional imaging criteria extracted from FDG-PET imaging to morphological plaque characteristics identified with CTA might improve the detection of complicated plaques.Material and MethodsTwenty-eight patients scheduled for carotid endarterectomy were imaged with PET after injection of FDG followed by CTA of the supra-aortic trunks. Morphological aspects of plaques identified with CTA and metabolic activity quantified with FDG-PET (Tissue to Background ratio, TBR) were measured in the carotid segment with the highest degree of luminal stenosis and graded using semi-quantitative CT and PET scores. Combined score was calculated for each carotid artery by summing CT and PET scores. After carotid endarterectomy, vascular surgeons classified carotid plaques macroscopically as complicated or non-complicated.ResultsTwenty-eight carotid arteries were operated in 26 patients (24 symptomatic patients). Sixteen plaques were classified macroscopically as complicated. CTA detected hypodense regions and ulcerations in 81% and 25%, of complicated plaques, and in 33% and 0% of non-complicated plaques, respectively. Hypodense areas on CTA identified complicated plaques with a sensitivity of 87% and a specificity of 67%. Mean TBR with FDG-PET was measured at 2.2±0.4 in complicated plaques and 1.9±0.3 in non-complicated plaques (p<0.05). Values for the semi-quantitative score based on plaques characteristics with CTA and FDG-PET were 5.4±1.7 in complicated plaques and 2.5±2.4 in non-complicated plaques (p<0.05). A combined PET-CT score≥3 identified complicated plaques with a sensitivity of 100% and a specificity of 67%.ConclusionsAdding FDG-PET imaging criteria to morphological characteristics of plaques on CTA improved the sensitivity of the detection of complicated carotid plaques

99mTc-besilesomab (Scintimun®) in peripheral osteomyelitis: comparison with 99mTc-labelled white blood cells

The diagnosis of osteomyelitis is a challenge for diagnostic imaging. Nuclear medicine procedures including white blood cell imaging have been successfully used for the identification of bone infections. This multinational, phase III clinical study in 22 European centres was undertaken to compare anti-granulocyte imaging using the murine IgG antibody besilesomab (Scintimun) with (99m)Tc-labelled white blood cells in patients with peripheral osteomyelitis. A total of 119 patients with suspected osteomyelitis of the peripheral skeleton received (99m)Tc-besilesomab and (99m)Tc-hexamethylpropyleneamine oxime (HMPAO)-labelled white blood cells (WBCs) in random order 2-4 days apart. Planar images were acquired at 4 and 24 h after injection. All scintigraphic images were interpreted in an off-site blinded read by three experienced physicians specialized in nuclear medicine, followed by a fourth blinded reader for adjudication. In addition, clinical follow-up information was collected and a final diagnosis was provided by the investigators and an independent truth panel. Safety data including levels of human anti-mouse antibodies (HAMA) and vital signs were recorded. The agreement in diagnosis across all three readers between Scintimun and (99m)Tc-HMPAO-labelled WBCs was 0.83 (lower limit of the 95% confidence interval 0.8). Using the final diagnosis of the local investigator as a reference, Scintimun had higher sensitivity than (99m)Tc-HMPAO-labelled WBCs (74.8 vs 59.0%) at slightly lower specificity (71.8 vs 79.5%, respectively). All parameters related to patient safety (laboratory data, vital signs) did not provide evidence of an elevated risk associated with the use of Scintimun except for two cases of transient hypotension. HAMA were detected in 16 of 116 patients after scan (13.8%). Scintimun imaging is accurate, efficacious and safe in the diagnosis of peripheral bone infections and provides comparable information to (99m)Tc-HMPAO-labelled WBCs

255 In vivo detection of non-occlusive thrombi in drug-eluting stents by scintigraphy and radio-labelled annexin V in a rabbit model

IntroductionThrombi in contact with non re-endothelialized stent struts associated with drug-eluting stent (DES) thrombosis. Hence, detection of thrombi in DES could help to evaluate the risk of DES thrombosis. Annexin V radio-labelled with 99mTechnetium (99mTc) is a radio-tracer with a high affinity for activated platelets.ObjectivesOur objectives were: 1) to develop an animal model of non-occlusive thrombosis of stents, 2) to evaluate the ability of annexin V 99mTc for the detection of in-stent thrombi using scintigraphy.MethodsRight carotid arteries of NZW rabbits (n=14) fed a high cholesterol diet were implanted with overlapping DES (n=7) or bare-metal stents (BMS; n=7). Four weeks after stent implantation, rabbits underwent a first scintigraphy 3 hours after injection of 200 MBq of radio-labelled annexin V 99mTc. At the end of the first scintigraphy, a suture was placed surgically proximal to the stented carotid arteries in order to induce a thrombus-prone flow limiting stenosis. Four days later, a second scintigraphy was performed. After the second scintigraphy, stents were excised, imaged ex vivo and then fixed for histological examination and scanning electron microscopy (SEM).ResultsActivities measured in vivo in the stented carotid arteries after injection of annexin V 99mTc were higher on the second scintigraphy after creation of a surgical stenosis as compared to the first scintigraphy (0.24 vs. 0.15 counts/pixel/MBq, respectively; p<0.05). On the second scintigraphy, activities were higher in DES vs. BMS (0.26 vs. 0.19 counts/pixel/MBq, respectively; p < 0.005). High activities measured in stents in vivo were associated with the detection of thrombi on corresponding histological sections and SEM.ConclusionsIn this work, we developed a rabbit model of non-occlusive thrombosis of stents in carotid arteries. In this model, in-stent thrombi could be detected using annexin V 99mTc scintigraphy

Non-Invasive Molecular Imaging of Fibrosis Using a Collagen-Targeted Peptidomimetic of the Platelet Collagen Receptor Glycoprotein VI

Background: Fibrosis, which is characterized by the pathological accumulation of collagen, is recognized as an important feature of many chronic diseases, and as such, constitutes an enormous health burden. We need non-invasive specific methods for the early diagnosis and follow-up of fibrosis in various disorders. Collagen targeting molecules are therefore of interest for potential in vivo imaging of fibrosis. In this study, we developed a collagen-specific probe using a new approach that takes advantage of the inherent specificity of Glycoprotein VI (GPVI), the main platelet receptor for collagens I and III. Methodology/Principal: Findings An anti-GPVI antibody that neutralizes collagen-binding was used to screen a bacterial random peptide library. A cyclic motif was identified, and the corresponding peptide (designated collagelin) was synthesized. Solid-phase binding assays and histochemical analysis showed that collagelin specifically bound to collagen (Kd 10−7 M) in vitro, and labelled collagen fibers ex vivo on sections of rat aorta and rat tail. Collagelin is therefore a new specific probe for collagen. The suitability of collagelin as an in vivo probe was tested in a rat model of healed myocardial infarctions (MI). Injecting Tc-99m-labelled collagelin and scintigraphic imaging showed that uptake of the probe occurred in the cardiac area of rats with MI, but not in controls. Post mortem autoradiography and histological analysis of heart sections showed that the labeled areas coincided with fibrosis. Scintigraphic molecular imaging with collagelin provides high resolution, and good contrast between the fibrotic scars and healthy tissues. The capacity of collagelin to image fibrosis in vivo was confirmed in a mouse model of lung fibrosis. Conclusion/Significance: Collagelin is a new collagen-targeting agent which may be useful for non-invasive detection of fibrosis in a broad spectrum of diseases.Psycholog

Multicentre multi-device hybrid imaging study of coronary artery disease: results from the EValuation of INtegrated Cardiac Imaging for the Detection and Characterization of Ischaemic Heart Disease (EVINCI) hybrid imaging population

AIMS: Hybrid imaging provides a non-invasive assessment of coronary anatomy and myocardial perfusion. We sought to evaluate the added clinical value of hybrid imaging in a multi-centre multi-vendor setting. METHODS AND RESULTS: Fourteen centres enrolled 252 patients with stable angina and intermediate (20-90%) pre-test likelihood of coronary artery disease (CAD) who underwent myocardial perfusion scintigraphy (MPS), CT coronary angiography (CTCA), and quantitative coronary angiography (QCA) with fractional flow reserve (FFR). Hybrid MPS/CTCA images were obtained by 3D image fusion. Blinded core-lab analyses were performed for CTCA, MPS, QCA and hybrid datasets. Hemodynamically significant CAD was ruled-in non-invasively in the presence of a matched finding (myocardial perfusion defect co-localized with stenosed coronary artery) and ruled-out with normal findings (both CTCA and MPS normal). Overall prevalence of significant CAD on QCA (&gt;70% stenosis or 30-70% with FFR 640.80) was 37%. Of 1004 pathological myocardial segments on MPS, 246 (25%) were reclassified from their standard coronary distribution to another territory by hybrid imaging. In this respect, in 45/252 (18%) patients, hybrid imaging reassigned an entire perfusion defect to another coronary territory, changing the final diagnosis in 42% of the cases. Hybrid imaging allowed non-invasive CAD rule-out in 41%, and rule-in in 24% of patients, with a negative and positive predictive value of 88% and 87%, respectively. CONCLUSION: In patients at intermediate risk of CAD, hybrid imaging allows non-invasive co-localization of myocardial perfusion defects and subtending coronary arteries, impacting clinical decision-making in almost one every five subjects

Apport de l'imagerie au 2-[fluorine 18]-fluoro-2-deoxy-D-glucose ou [18F]FDG dans le bilan d'extension des cancers bronchopulmonaires non à petites cellules (comparaison de 2 systèmes de détection en coïncidence)

POITIERS-BU Médecine pharmacie (861942103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Tomoscintigraphie cavitaire cardiaque synchronisée à l'électrocardiogramme

Différentes modalités d'imagerie non invasives se proposent de quantifier la fonction contractile cardiaque. Pour la médecine nucléaire, il s'agit de la ventriculographie isotopique à l'équilibre synchronisée à l'électrocardiogramme. Malgré les limites inhérentes à son mode d'acquisition bidimensionnelle (planaire), cette technique s'est largement imposée comme la méthode de référence de la quantification de la fonction ventriculaire gauche. Les progrès technologiques réalisés dernièrement rendent possible la réalisation de l'examen en mode tridimensionnel (tomographique). Ce mode d'acquisition devrait permettre de s'affranchir de différentes limites inhérentes au mode planaire. A cette étape, c'est la détermination des méthodes optimales de traitement des données acquises qui limitent la diffusion de la tomoventriculographie isotopique synchronisée à l'électrocardiogramme. Dans notre travail, nous évaluons différentes méthodes de traitement du mode tomographique. Nous détaillons leurs performances et décrivons leurs avantages et leurs inconvénients ainsi que leurs robustesses aux différentes conditions d'acquisitions.Various non-invasive imaging modalities propose to quantify the cardiac contractile function. For nuclear medicine, this is usually accomplished with planar electrocardiographye-gated radionuclide angiography. In spite of the limits inherent to its two-dimensional mode of acquisition, this technique is largery considered in clinical practice as the method of refernece for the quantification of the left ventricular function. Recent technological progress makes possible its realization in three-dimensional mode (tomography). This mode of acquisition should make it possible to be freed from various limits inherent to the planar mode of acquisition. At this stage, it is the determination of the optimal methods to be used for the processing of gathered data in the tomographic mode which limits its diffusion to practice clinical. In our work, we evaluate various methods of processing the tomographic acquisitions. We detail their performances and their robustness.PARIS12-CRETEIL BU Multidisc. (940282102) / SudocSudocFranceF