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1.
Clin. transl. oncol. (Print) ; 23(10): 2181-2190, oct. 2021.
Artigo em Inglês | IBECS | ID: ibc-223389

RESUMO

Purpose Chimeric antigen receptor (CAR) T cell development for B cell malignancies treatment has triggered a paradigm shift in oncology. The development of anti-CD19 CAR T cells relies primarily on a panel of cell line-derived xenograft models, including Raji cells; however, the behavior of this model is under debate. We attempted to characterize this lymphoma model and propose outcome measures for CAR T cell studies Methods Raji cell line was inoculated into NOG mice via intra-venous (IV), intra-peritoneal (IP), and subcutaneous (SC) routes with different inoculum sizes, and consequent clinical and histopathological outcomes were assessed. Results Inoculum sizes of 105–106 resulted in a complete take rate. The mice with IV and SC-inoculated Raji cells presented the shortest and longest survival among lymphoma-bearing mice, respectively (P < 0.01). The IP group had the highest number of both infiltrated organs (P < 0.05; compared to SC) and involvement of lymphatic sites (P < 0.05; compared to IV). The number of lymphoma lesions on the liver was higher in the IV compared to IP (P < 0.001) and SC (P < 0.05). Conclusion We demonstrate that the Raji cell line inoculation route could determine the xenograft model system behavior in terms of survival, tumor burden, and dissemination pattern and gives the model the specific features suitable for testing the specific hypothesis in CAR T cell therapy. We also conclude outcome measures for CAR T cell studies that do not require imaging techniques (AU)


Assuntos
Animais , Masculino , Feminino , Camundongos , Antígenos CD19/imunologia , Imunoterapia Adotiva/métodos , Linfoma não Hodgkin/terapia , Receptores de Antígenos Quiméricos , Ensaios Antitumorais Modelo de Xenoenxerto , Linhagem Celular Tumoral , Modelos Animais de Doenças , Linfoma não Hodgkin/mortalidade , Linfoma não Hodgkin/patologia , Camundongos Endogâmicos NOD , Invasividade Neoplásica , Distribuição Aleatória , Linfócitos T/imunologia , Peso Corporal
2.
Clin Transl Oncol ; 23(10): 2181-2190, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33942221

RESUMO

PURPOSE: Chimeric antigen receptor (CAR) T cell development for B cell malignancies treatment has triggered a paradigm shift in oncology. The development of anti-CD19 CAR T cells relies primarily on a panel of cell line-derived xenograft models, including Raji cells; however, the behavior of this model is under debate. We attempted to characterize this lymphoma model and propose outcome measures for CAR T cell studies METHODS: Raji cell line was inoculated into NOG mice via intra-venous (IV), intra-peritoneal (IP), and subcutaneous (SC) routes with different inoculum sizes, and consequent clinical and histopathological outcomes were assessed. RESULTS: Inoculum sizes of 105-106 resulted in a complete take rate. The mice with IV and SC-inoculated Raji cells presented the shortest and longest survival among lymphoma-bearing mice, respectively (P < 0.01). The IP group had the highest number of both infiltrated organs (P < 0.05; compared to SC) and involvement of lymphatic sites (P < 0.05; compared to IV). The number of lymphoma lesions on the liver was higher in the IV compared to IP (P < 0.001) and SC (P < 0.05). CONCLUSION: We demonstrate that the Raji cell line inoculation route could determine the xenograft model system behavior in terms of survival, tumor burden, and dissemination pattern and gives the model the specific features suitable for testing the specific hypothesis in CAR T cell therapy. We also conclude outcome measures for CAR T cell studies that do not require imaging techniques.


Assuntos
Antígenos CD19/imunologia , Imunoterapia Adotiva/métodos , Linfoma não Hodgkin/terapia , Receptores de Antígenos Quiméricos , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , Animais , Peso Corporal , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Linfoma não Hodgkin/mortalidade , Linfoma não Hodgkin/patologia , Masculino , Camundongos , Camundongos Endogâmicos NOD , Invasividade Neoplásica , Distribuição Aleatória , Linfócitos T/imunologia
3.
J Med Life ; 8(Spec Iss 3): 107-112, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-28316675

RESUMO

Responsiveness was proposed via WHO as a fundamental sign to evaluate the enforcement of wellness practices and evaluates with a standard organization of fields that are classified to 2 principal classes "Respect as characters" and "customer adjustment". The current research included the value of customer adjustment areas in low and high-income communities of Mashhad. In the current descriptive research, an example of 923 families was chosen stochastically of 2 low and high pay areas of Mashhad. WHO survey employed for information gathering. Regular rate reviews and Ordinal Logistic Regression (OLR) applied for information investigation. In overall, respondents chose basic amenities quality as the primary area, and the path to social care networks recognized as the wicked primary area. Families in high-income states obtained higher areas of immediate notations and selection associated with low-income. There is a meaningful correlation among parameters of ages, having a part whom required care and self-imposed health via the ranking of customer adjustment areas. The investigation of the homes' viewpoint concerning the classification of non-clinical perspectives of care quality, particularly while confronted by restricted sources, can assist in managing enterprises towards topics that are more relevant and results in the development of the wellness policy achievement and fecundity.

4.
Rev Sci Instrum ; 85(6): 063702, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24985822

RESUMO

We developed an ultrafast time-resolved magneto-optical (MO) imaging system with several millidegree resolution of light polarization angle, 100 fs time-resolution, and a micrometer spatial resolution. A CCD camera with about 10(6) pixels is used for detection and MO images with an absolute angle of the light polarization are acquired by the rotating analyzer method. By optimizing the analysis procedure with a least square method and the help of graphical processor units, this novel system significantly improves the speed for MO imaging, allowing to obtain a MO map of a sample within 15 s. To demonstrate the strength of the technique, we applied the method in a pump-and-probe experiment of all-optical switching in a GdFeCo sample in which we were able to detect temporal evolution of the MO images with sub-picosecond resolution.

6.
Phys Rev Lett ; 110(17): 177205, 2013 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-23679767

RESUMO

We report the creation and real-space observation of magnetic structures with well-defined topological properties and a lateral size as low as about 150 nm. They are generated in a thin ferrimagnetic film by ultrashort single optical laser pulses. Thanks to their topological properties, such structures can be classified as Skyrmions of a particular type that does not require an externally applied magnetic field for stabilization. Besides Skyrmions, we are able to generate magnetic features with topological characteristics that can be tuned by changing the laser fluence. The stability of such features is accounted for by an analytical model based on the interplay between the exchange and the magnetic dipole-dipole interactions.

7.
Phys Rev Lett ; 110(10): 107205, 2013 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-23521292

RESUMO

We demonstrate the feasibility of element-specific probing of ultrafast spin dynamics in the multisublattice magnet TbFe in the visible spectral range. In particular, we show that one can selectively study the dynamics of Tb and Fe sublattices choosing the wavelength of light below and above 610 nm, respectively. We observe that, despite their antiferromagnetic coupling in the ground state, the Tb and Fe spins temporarily align ferromagnetically after excitation with an intense 55-fs laser pulse, after which they relax to their initial states due to the strong anisotropy in Tb.

8.
J Dent (Tehran) ; 9(2): 116-27, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23066476

RESUMO

OBJECTIVE: The objective of this study was to evaluate the effect of Accell Connexus(®) on the quality and rate of healing in experimental defects of rabbit calvarium compared to Bio-Oss®. MATERIALS AND METHODS: Twelve 2.5-3.5 kg weighing New Zealand white rabbits were used. Three defects (3×6 mm) were created in the cranium of the animals subsequently filled with Accell Connexus(®), Bio-Oss® or served as controls. The animals were sacrificed four, six and eight weeks postoperatively and the histology blocks were studied in terms of inflammation, trabeculation thickness, bone type regeneration, foreign body and remained biomaterial by light microscope. The data were subject to Mann-Whitney U test. RESULTS: Increased inflammatory reaction, foreign body reaction, delayed bone formation and lower rate of ossification were observed in DBM-filled defects compared to Bio-Oss® or controls. However, no significant differences were observed in bone formation between Bio-Oss®, Accell Connexus(®) and control specimens in the three time intervals. Furthermore, no significant differences were noted between Bio-Oss® and control groups. CONCLUSION: Accell Connexus(®) showeda lower rate of ossification and bone healing compared to Bio-Oss® or controlgroups. Other studies in this field seem necessary.

9.
Phys Rev Lett ; 108(12): 127205, 2012 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-22540622

RESUMO

Using magneto-optical microscopy in combination with ellipsometry measurements, we show that all-optical switching with polarized femtosecond laser pulses in ferrimagnetic GdFeCo is subjected to a threshold fluence absorbed in the magnetic layer, independent of either the excitation wavelength or the polarization of the laser pulse. Furthermore, we present a quantitative explanation of the intensity window in which all-optical helicity-dependent switching (AO-HDS) occurs, based on magnetic circular dichroism. This explanation is consistent with all the experimental findings on AO-HDS so far, varying from single- to multiple-shot experiments. The presented results give a solid understanding of the origin of AO-HDS, and give novel insights into the physics of ultrafast, laser controlled magnetism.

10.
Opt Express ; 19(1): 193-205, 2011 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-21263557

RESUMO

We investigated the damage mechanism of MoN/SiN multilayer XUV optics under two extreme conditions: thermal annealing and irradiation with single shot intense XUV pulses from the free-electron laser facility in Hamburg - FLASH. The damage was studied "post-mortem" by means of X-ray diffraction, interference-polarizing optical microscopy, atomic force microscopy, and scanning transmission electron microscopy. Although the timescale of the damage processes and the damage threshold temperatures were different (in the case of annealing it was the dissociation temperature of Mo2N and in the case of XUV irradiation it was the melting temperature of MoN) the main damage mechanism is very similar: molecular dissociation and the formation of N2, leading to bubbles inside the multilayer structure.

11.
Nuklearmedizin ; 50(1): 9-14, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21165540

RESUMO

AIM: We compared and delineated possible differences of model-based analysis of ECG-gated SPECT using (99m)Tc-sestamibi (Tc-SPECT) with ECG-gated ¹8F-fluorodeoxyglucose-PET (FDG-PET) for determination of end-diastolic (EDV) and end-systolic (ESV) cardiac volumes, left ventricular ejection fraction (LVEF), and myocardial mass (LVMM). PATIENTS, METHODS: 24 patients (21 men; age: 54±12years) with coronary artery disease underwent Tc-SPECT and FDG-PET imaging for evaluation of myocardial perfusion and viability. By using model-based analysis EDV, ESV, LVEF and LVMM were calculated from short axis images of both Tc-SPECT and FDG-PET. RESULTS: Left ventricular volumes by Tc-SPECT and FDG-PET were 176±60 ml and 181±59 ml for EDV, and 97±44 ml and 103±45 ml for ESV respectively, LVEF was 47±8% by Tc-SPECT and 45±9% by FDG-PET. The LVMM was 214±40 g (Tc-SPECT) and 202±43 g (FDG-PET) (all p = NS, paired t-test). A significant correlation was observed between Tc-SPECT and FDG-PET imaging for calculation of EDV (r = 0.93), ESV (r = 0.93), LVEF (r = 0.83) and LVMM (r = 0.72). CONCLUSION: ECG-gated Tc-SPECT and FDG-PET using two tracers with different characteristics (perfusion versus metabolism) showed close agreement concerning measurements of left ventricular volumes, contractile function and myocardial mass by using a model-based analysis.


Assuntos
Técnicas de Imagem de Sincronização Cardíaca/métodos , Fluordesoxiglucose F18 , Volume Sistólico , Tecnécio , Disfunção Ventricular Esquerda/diagnóstico por imagem , Feminino , Fluordesoxiglucose F18/farmacocinética , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos/farmacocinética , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Tecnécio/farmacocinética , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Disfunção Ventricular Esquerda/metabolismo
12.
Opt Express ; 18(2): 700-12, 2010 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-20173890

RESUMO

We investigated single shot damage of Mo/Si multilayer coatings exposed to the intense fs XUV radiation at the Free-electron LASer facility in Hamburg - FLASH. The interaction process was studied in situ by XUV reflectometry, time resolved optical microscopy, and "post-mortem" by interference-polarizing optical microscopy (with Nomarski contrast), atomic force microscopy, and scanning transmission electron microcopy. An ultrafast molybdenum silicide formation due to enhanced atomic diffusion in melted silicon has been determined to be the key process in the damage mechanism. The influence of the energy diffusion on the damage process was estimated. The results are of significance for the design of multilayer optics for a new generation of pulsed (from atto- to nanosecond) XUV sources.


Assuntos
Membranas Artificiais , Molibdênio/química , Molibdênio/efeitos da radiação , Dispositivos Ópticos , Silício/química , Silício/efeitos da radiação , Desenho de Equipamento , Análise de Falha de Equipamento , Teste de Materiais , Raios Ultravioleta
13.
Opt Express ; 18(26): 27836-45, 2010 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-21197057

RESUMO

We present a new technique for the characterization of non-Gaussian laser beams which cannot be described by an analytical formula. As a generalization of the beam spot area we apply and refine the definition of so called effective area (A(eff)) [1] in order to avoid using the full-width at half maximum (FWHM) parameter which is inappropriate for non-Gaussian beams. Furthermore, we demonstrate a practical utilization of our technique for a femtosecond soft X-ray free-electron laser. The ablative imprints in poly(methyl methacrylate) - PMMA and amorphous carbon (a-C) are used to characterize the spatial beam profile and to determine the effective area. Two procedures of the effective area determination are presented in this work. An F-scan method, newly developed in this paper, appears to be a good candidate for the spatial beam diagnostics applicable to lasers of various kinds.


Assuntos
Lasers , Modelos Estatísticos , Simulação por Computador , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Distribuição Normal , Espalhamento de Radiação , Raios X
14.
J Dent (Tehran) ; 7(2): 89-97, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-21998781

RESUMO

OBJECTIVE: Vertical bone loss evaluations in the Nobel Biocare Replace(®) Select Tapered (™) implant system in the human after one-year loading time. MATERIALS AND METHODS: This retrospective cross-sectional study was performed on 31 patients (14 men, 17 women; mean age, 60.39 years) receiving 170 implants (mean, 5.48 for each patient) of Groovy and Non-groovy designs in the Nobel Biocare Replace(®) Select Tapered (™) system. The marginal bone loss was measured at mesial and distal aspects of the implants on OPG x-rays after one-year follow-up. The data regarding the patient's gender, age, history of disease, smoking, bone type at implant location, loading time of prosthesis and implant, implant design, diameter and length were recorded by the patients' records and interview. The data were subjected to multiple linear regression and Pearson coefficient ratio regarding different factors. RESULTS: The mean (standard deviation) distal, mesial and overall bone loss was 0.688 mm (0.851), 0.665 mm (0.849) and 0.935 mm (0.905), respectively in the studied implants. No significant differences were found regarding implant location, bone quality at the implant region, implant design and bone graft reception. In addition, no significant correlation was found between the occurred bone loss and implant diameter, length and number of used splints. CONCLUSION: Due to the criteria mentioned for implant success in term of bone loss values after one-year loading time, Noble Biocare Replace(®) Select Tapered (™) implant system is an acceptable treatment option for implant restorations in this regard.

15.
Opt Express ; 17(20): 18271-8, 2009 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-19907618

RESUMO

We have focused a beam (BL3) of FLASH (Free-electron LASer in Hamburg: lambda = 13.5 nm, pulse length 15 fs, pulse energy 10-40 microJ, 5 Hz) using a fine polished off-axis parabola having a focal length of 270 mm and coated with a Mo/Si multilayer with an initial reflectivity of 67% at 13.5 nm. The OAP was mounted and aligned with a picomotor controlled six-axis gimbal. Beam imprints on poly(methyl methacrylate) - PMMA were used to measure focus and the focused beam was used to create isochoric heating of various slab targets. Results show the focal spot has a diameter of < or =1 microm. Observations were correlated with simulations of best focus to provide further relevant information.


Assuntos
Lasers , Lentes , Teste de Materiais/instrumentação , Teste de Materiais/métodos , Difração de Raios X/instrumentação , Difração de Raios X/métodos , Desenho Assistido por Computador , Elétrons , Desenho de Equipamento , Análise de Falha de Equipamento , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
16.
Heart ; 94(12): 1627-33, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18381378

RESUMO

BACKGROUND: Impairment of myocardial flow reserve (MFR) in aortic stenosis (AS) with normal left ventricular function relates to the haemodynamic severity. OBJECTIVES: To investigate whether myocardial blood flow (MBF) and MFR differ in low-flow, low-gradient AS depending on whether there is underlying true-severe AS (TSAS) or pseudo-severe AS (PSAS). METHODS: In 36 patients with low-flow, low-gradient AS, dynamic [13N]ammonia PET perfusion imaging was performed at rest (n = 36) and during dipyridamole stress (n = 20) to quantify MBF and MFR. Dobutamine echocardiography was used to classify patients as TSAS (n = 18) or PSAS (n = 18) based on the indexed projected effective orifice area (EOA) at a normal flow rate of 250 ml/s (EOAI(proj )0.55 cm(2)/m(2)). RESULTS: Compared with healthy controls (n = 14), patients with low-flow, low-gradient AS had higher resting mean (SD) MBF (0.83 (0.21) vs 0.69 (0.09) ml/min/g, p = 0.001), reduced hyperaemic MBF (1.16 (0.31) vs 2.71 (0.50) ml/min/g, p<0.001) and impaired MFR (1.44 (0.44) vs 4.00 (0.91), p<0.001). Resting MBF and MFR correlated with indices of AS severity in low-flow, low-gradient AS with the strongest relationship observed for EOAI(proj) (r(s) = -0.50, p = 0.002 and r(s) = 0.61, p = 0.004, respectively). Compared with PSAS, TSAS had a trend to a higher resting MBF (0.90 (0.19) vs 0.77 (0.21) ml/min/g, p = 0.06), similar hyperaemic MBF (1.16 (0.31) vs 1.17 (0.32) ml/min/g, p = NS), but a significantly smaller MFR (1.19 (0.26) vs 1.76 (0.41), p = 0.003). An MFR <1.8 had an accuracy of 85% for distinguishing TSAS from PSAS. CONCLUSIONS: Low-flow, low-gradient AS is characterised by higher resting MBF and reduced MFR that relates to the AS severity. The degree of MFR impairment differs between TSAS and PSAS and may be of value for distinguishing these entities.


Assuntos
Estenose da Valva Aórtica/diagnóstico , Circulação Coronária/fisiologia , Adulto , Idoso , Estenose da Valva Aórtica/fisiopatologia , Velocidade do Fluxo Sanguíneo/fisiologia , Estudos de Casos e Controles , Ecocardiografia sob Estresse , Feminino , Humanos , Masculino , Tomografia por Emissão de Pósitrons , Adulto Jovem
17.
Nuklearmedizin ; 45(6): 248-53, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17149493

RESUMO

AIM: Hyperhomocysteinaemia (Hhcy) is known to be an independent risk factor for vascular disease. Coronary flow reserve (CFR) measured by positron emission tomography (PET) is a sensitive method to monitor the effects of pharmacologic interventions in Hhcy. We assessed coronary vascular reactivity by PET in patients with coronary artery disease (CAD) dependent on their homocysteine (Hcy) levels before and under high dose folic acid supplementation therapy (FAST). PATIENTS, METHODS: Twelve patients with CAD underwent rest/adenosine (13) N-ammonia PET for quantification of myocardial blood flow (MBF) and CFR before and after nine weeks FAST (10 mg/day). RESULTS: Folate levels increased from 21 +/- 6 to 210 +/- 34 microg/l (+900%, p < 0.0001) while Hcy levels decreased from 12.1 +/- 3.6 to 9.1 +/- 3.1 micromol/l ( - 25%; p < 0.01). Global resting MBF remained nearly unchanged after FAST, while stress MBF (from 2.61 +/- 0.93 to 3.25 +/- 1.15 ml/g/min; p = 0.05) and CFR (from 3.00 +/- 0.76 to 3.72 +/- 0.93 ml/g/min; p < 0.05; +24%) significantly increased in patients with normal and elevated Hcy levels (cut off 12 micromol/l). An inverse relation was found between Hcy and CFR (R = - 0.53; p = 0.08) and between Hcy and MBF at rest (R = - 0.62; p < 0.05) at baseline conditions, not persisting after FAST. CONCLUSION: Coronary vascular reactivity can be improved by FAST in patients with CAD and normal or elevated Hcy levels. FAST might lower an increased cardiovascular risk in CAD patients possibly by mechanisms that are not related to Hcy.


Assuntos
Amônia , Doença das Coronárias/diagnóstico por imagem , Teste de Esforço , Ácido Fólico/uso terapêutico , Homocisteína/sangue , Radioisótopos de Nitrogênio , Idoso , Angiografia Coronária , Feminino , Humanos , Hiper-Homocisteinemia/sangue , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons , Valores de Referência
18.
Nuklearmedizin ; 45(4): 163-70, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16964342

RESUMO

UNLABELLED: Metabolic imaging with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) is actually considered as the best method to detect and quantitatively assess myocardial tissue viability. The aim of this study was to investigate the accuracy of FDG gamma camera positron emission tomography (GCPET) imaging equipped with one inch NaI crystals in comparison to FDG dedicated PET (dPET) imaging as a "gold standard" in phantom and clinical studies. PATIENTS, METHODS: Nineteen patients with coronary artery disease (CAD) underwent both imaging modalities. Phantom and clinical GCPET imaging were performed with a dual-headed, coincidence based gamma camera equipped with 1 inch thick NaI crystals and an x-ray tube (XCT) for attenuation correction (AC), as well as with a dedicated PET scanner with AC. (99m)Tc tetrofosmin single-photon emission tomography (SPET) studies were performed for assessment of myocardial perfusion, with AC. RESULTS: Phantom studies showed a significant relation in segmental activity between FDG imaging with AC using GCPET and dPET (r = 0.91, p < 0.001). In clinical studies with AC correlation coefficients of mean segmental FDG uptake and regional defect size were r = 0.87 (p < 0.0001) and r = 0.83 (p < 0.0001), respectively. In regional analysis close agreement was even found in the most attenuated regions of the heart if AC was used in GCPET imaging. The overall agreement for detection of viable myocardium was 81% between FDG-dPET (AC) and FDG-GCPET (AC) and 74% between FDG-dPET (AC) and FDG-GCPET (NC). CONCLUSION: This study suggests that the assessment of myocardial metabolism by means of FDG is feasible with a coincidence based gamma camera equipped with 1 inch thick NaI crystals if AC is performed. The results reveal a close concordance and agreement between FDG-dPET (AC) and FDG-GCPET (AC) as compared to FDG-GCPET (NC).


Assuntos
Doença das Coronárias/diagnóstico por imagem , Fluordesoxiglucose F18 , Câmaras gama , Tomografia por Emissão de Pósitrons/instrumentação , Tomografia por Emissão de Pósitrons/métodos , Idoso , Desenho de Equipamento , Feminino , Fluordesoxiglucose F18/farmacocinética , Humanos , Masculino , Pessoa de Meia-Idade , Imagens de Fantasmas , Compostos Radiofarmacêuticos/farmacocinética , Reprodutibilidade dos Testes
19.
Nuklearmedizin ; 45(4): 171-6, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16964343

RESUMO

AIM: We investigated the impact of photon attenuation in myocardial perfusion imaging with SPECT and PET in patients with coronary artery disease. In fact, the regional tracer distribution can be quantitatively assessed by polar map analysis if the effects of photon attenuation are accounted for. PET imaging permits accurate measurement of and correction for photon attenuation, whereas results of attenuation correction in SPECT imaging have been inconsistent. PATIENTS, METHODS: We compared photon attenuation in resting perfusion imaging studies with SPECT ((99m)Tc-sestamibi) and PET ((13)N-ammonia) from 21 patients. Transaxial images were reconstructed with and without attenuation correction and reoriented into short axis images. Polar map analysis was utilized to generate regional tracer uptake in six anatomical segments. RESULTS: Average segmental photon attenuation calculated as the ratio of counts in corrected and uncorrected images was 7.2 +/- 1.4 in SPECT and 14.0 +/- 3.1 in PET imaging (p < 0.01). This attenuation factor was significantly related to body mass index for both methods (p < 0.001). While attenuation correction for SPECT imaging did compensate for attenuation effects in the inferior wall (from -15% to +6% vs. PET), relative tracer uptake in the anterior wall in SPECT images was significantly reduced after attenuation correction (from -2% to -18% vs. PET, p < 0.01). CONCLUSION: Differential effects of attenuation correction for myocardial SPECT perfusion imaging need to be considered when algorithms designed to compensate effects of photon attenuation in SPECT imaging are employed in clinical practice.


Assuntos
Doença das Coronárias/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Imagens de Fantasmas , Compostos Radiofarmacêuticos , Sensibilidade e Especificidade , Tecnécio Tc 99m Sestamibi
20.
Eur J Clin Invest ; 36(5): 326-32, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16634836

RESUMO

BACKGROUND: Approximately 10-30% of patients with typical chest pain present normal epicardial coronaries. In a proportion of these patients, angina is attributed to microvascular dysfunction. Previous studies investigating whether angina is the result of abnormal resting or stress perfusion are controversial but limited by varying inclusion criteria. Therefore, we investigated whether microvascular dysfunction in these patients is associated with perfusion abnormalities at rest or at stress. PATIENTS AND METHODS: In 58 patients (39 female, 19 male, mean age 58+/-10 years) with angina and normal angiogram as well as 10 control patients with atypical chest pain and normal coronaries (six female, four male, mean age 53+/-11 years) myocardial blood flow (MBF) was measured at rest and under dipyridamole using 13N-ammonia PET. Resting MBF and coronary flow reserve (CFR) as the ratio of hyperaemic to resting MBF were corrected for rate-pressure-product (RPP): normalized resting MBF (MBFn)=MBFx10,000/RPP and CFRn=CFRxRPP/10,000. RESULTS: Sixteen/58 patients had a normal CFRn (=2.5; group I; CFRn: 3.1+/-0.88); the same as the controls (CFRn: 3.3+/-0.74). Forty-two/58 patients presented a reduced CFRn (group II; CFRn: 1.78+/-0.57). Group II had both a higher MBFn (group II: 1.30+/-0.33 vs. Group I: 1.03+/-0.26; P<0.05 and vs. controls: 1.07+/-0.19; P<0.01) and a lower hyperaemic MBF (group II: 2.25+/-0.76 mL g-1 min-1 vs. Group I: 3.07+/-0.78 mL g-1 min-1; P<0.001 and vs. controls: 3.41+/-0.94 mL g-1 min-1; P<0.0001). CONCLUSION: Impaired CFRn in patients with typical angina and normal angiogram is owing to both an increased resting and reduced hyperaemic MBF. Therefore, PET represents a prerequisite for further studies to optimize treatment in individuals with anginal pain and normal coronary angiogram.


Assuntos
Circulação Coronária , Angina Microvascular/fisiopatologia , Adulto , Idoso , Angiografia Coronária , Teste de Esforço , Feminino , Humanos , Hiperemia/fisiopatologia , Processamento de Imagem Assistida por Computador/métodos , Masculino , Angina Microvascular/diagnóstico por imagem , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons , Resistência Vascular
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