RESUMO
BACKGROUND: Image acquisition by short-time single-photon emission-computed tomography (SPECT) has been made feasible by IQ·SPECT. The aim of this study was to generate normal databases (NDBs) of thallium-201 (201Tl) myocardial perfusion imaging for IQ·SPECT, and characterize myocardial perfusion distribution. METHODS AND RESULTS: We retrospectively enrolled 159 patients with a low likelihood of cardiac diseases from four hospitals in Japan. All patients underwent short-time 201Tl myocardial perfusion IQ·SPECT with or without attenuation and scatter correction (ACSC) in either supine or prone position. The mean myocardial counts were calculated using 17-segment polar maps. Three NDBs were derived from supine and prone images as well as supine images with ACSC. Differences between the supine and prone positions were observed in the uncorrected sex-segregated NDBs in the mid-inferolateral counts (p ≤ 0.016 for males and p ≤ 0.002 for females). Differences between IQ·SPECT and conventional SPECT were also observed in the mid-anterior, inferolateral, and apical lateral counts (p ≤ 0.009 for males and p ≤ 0.003 for females). Apical low counts attributed to myocardial thinning were observed in the apical anterior and apex segments in the supine IQ·SPECT NDB with ACSC. CONCLUSIONS: There were significant differences between uncorrected supine and prone NDBs, between uncorrected supine NDB and supine NDB with ACSC, and between uncorrected supine NDB and conventional SPECT NDB. Understanding the pattern of normal distribution in IQ-SPECT short-time acquisitions with and without ACSC will be helpful for interpretation of imaging findings in patients with coronary artery disease (CAD) or low likelihood of CAD and the NDBs will aid in quantitative analysis.
Assuntos
Imagem de Perfusão do Miocárdio/métodos , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Idoso , Idoso de 80 Anos ou mais , Bases de Dados Factuais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Decúbito Ventral , Estudos Retrospectivos , Decúbito Dorsal , Radioisótopos de TálioRESUMO
BACKGROUND: Myocardial injury can be detected more sensitively using (123)I-radioiodinated 15-(p-iodophenyl)-3(R,S)-methylpentadecanoic acid (BMIPP) than thallium-201 (TL). The present study investigated whether (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) uptake as an index of active inflammation in patients with cardiac sarcoidosis (CS) is associated with BMIPP and TL findings, and whether dual single-photon emission computed tomography (SPECT) can facilitate diagnosis of CS. METHODSâANDâRESULTS: We retrospectively enrolled 52 consecutive patients with suspected CS who were assessed on FDG-PET/computed tomography (CT) and BMIPP/TL dual SPECT. The SPECT images were divided into 17 segments and then BMIPP and TL total defect scores (BMDS, TLDS) as well as mismatch scores (BMDS-TLDS: sumMS) were calculated. Maximum standardized uptake value (SUVmax) in the entire myocardium was obtained from FDG-PET/CT. SUVmax was much higher in patients with, than without CS (P<0.0001). BMDS was higher and sumMS much higher in CS (P<0.05 and P<0.0001, respectively). The sensitivity and specificity of sumMS to detect CS were 74% and 80%, respectively. SUVmax was not associated with either BMDS or sumMS in the patients with CS. On multivariate analysis, the combination of sumMS and SUVmax had greater prognostic significance compared with each parameter on its own. CONCLUSIONS: BMIPP and TL dual-tracer mismatch is a useful finding to diagnose CS, and adds greater diagnostic value to SUVmax on FDG-PET/CT.
Assuntos
Cardiomiopatias , Ácidos Graxos/metabolismo , Miocárdio/metabolismo , Tomografia por Emissão de Pósitrons , Sarcoidose , Adulto , Idoso , Cardiomiopatias/diagnóstico , Cardiomiopatias/diagnóstico por imagem , Cardiomiopatias/metabolismo , Ácidos Graxos/administração & dosagem , Feminino , Humanos , Iodobenzenos/administração & dosagem , Masculino , Pessoa de Meia-Idade , Radiografia , Sarcoidose/diagnóstico , Sarcoidose/diagnóstico por imagem , Sarcoidose/metabolismoRESUMO
BACKGROUND: Because of their high risk for cardiovascular events, we investigated the role of (123)I-betamethyl-p-iodophenyl-pentadecanoic acid (BMIPP) SPECT in evaluating the prognosis of diabetic patients with suspected coronary heart disease. METHODS AND RESULTS: We retrospectively registered 186 diabetic patients with suspected coronary heart disease, but no previous diagnosis of heart disease, who had been examined by BMIPP and thallium (TL) dual SPECT. They were followed for over 2 years. The dual SPECT images were scored to obtain summed defect scores for each SPECT image (BMDS, TLDS and mismatch score [MS]). The primary endpoint was the first incidence of all-cause cardiac events. The secondary endpoint was cardiac death. Clinical classical risk factors in addition to the stage of chronic kidney disease (CKD), as well as cardiac function, were included in the prognostic analysis. Cardiac events occurred in 39 patients, including 8 cardiac deaths. Kaplan-Meier analysis revealed significantly more frequent cardiac event rates in patients with than without MS ≥5 or BMDS ≥6 (P<0.0001). Cox hazard multivariate analysis showed that MS and CKD stage or BMIPP and CKD stage were independent predictors. Only hemodialysis was a significant prognostic indicator for cardiac death. CONCLUSIONS: BMIPP SPECT when combined with CKD stage accurately predicts cardiac events among diabetic patients with suspected ischemic heart disease.
Assuntos
Tomografia Computadorizada por Emissão de Fóton Único de Sincronização Cardíaca/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Complicações do Diabetes/diagnóstico por imagem , Ácidos Graxos/administração & dosagem , Iodobenzenos/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Tomografia Computadorizada por Emissão de Fóton Único de Sincronização Cardíaca/efeitos adversos , Doença da Artéria Coronariana/mortalidade , Morte , Complicações do Diabetes/mortalidade , Ácidos Graxos/efeitos adversos , Feminino , Humanos , Iodobenzenos/efeitos adversos , Masculino , Pessoa de Meia-Idade , Radiografia , Diálise Renal/efeitos adversos , Estudos Retrospectivos , Fatores de Risco , Tálio/administração & dosagemRESUMO
UNLABELLED: The quality of (18)F-FDG PET/CT images of overweight patients is often degraded. We evaluated the effect of optimizing injected dose or acquisition time on the quality of images of overweight patients using lutetium oxyorthosilicate PET/CT with high-performance detector electronics. METHODS: We initially retrospectively measured radioactivity concentrations and signal-to-noise ratios (SNRs) in the liver relative to body weight for 80 patients who had undergone (18)F-FDG PET/CT according to our standard protocol (injected dose, 3.7 MBq/kg; acquisition time, 2 min/bed position). The patients were grouped (n = 20 per group) according to baseline body weight as G1 (
Assuntos
Fluordesoxiglucose F18 , Sobrepeso/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos , Tomografia Computadorizada por Raios X/métodos , Feminino , Humanos , Fígado/diagnóstico por imagem , Masculino , Doses de RadiaçãoRESUMO
PURPOSE: Diabetic patients with chronic kidney disease (CKD) frequently develop cardiac events within several years of the initiation of haemodialysis. The present study assesses the prognostic significance of stress myocardial ECG-gated perfusion imaging (MPI) in patients with diabetic CKD requiring haemodialysis. METHODS: Fifty-five asymptomatic patients with diabetic stage V CKD and no history of heart disease scheduled to start haemodialysis were enrolled in this study (56 +/- 11 years old; 49 with type 2 diabetes mellitus). All patients underwent (201)Tl stress ECG-gated MPI 1 month before or after the initiation of haemodialysis to assess myocardial involvement. We evaluated SPECT images using 17-segment defect scores graded on a 5-point scale, summed stress score (SSS) and summed difference scores (SDS). The patients were followed up for at least 2 years (42 +/- 15 months) to determine coronary intervention (CI) and heart failure (HF) as soft events and acute myocardial infarction (AMI) and all causes of deaths as hard events. RESULTS: The frequencies of myocardial ischaemia, resting perfusion defects, low ejection fraction and left ventricular (LV) dilatation were 24, 20, 29 and 49%, respectively. Ten events (18%) developed during the follow-up period including four CI, one HF, one AMI and four sudden deaths. Multivariate Cox analysis selected SDS (p = 0.0011) and haemoglobin A(1c) (HbA(1c)) (p = 0.0076) as independent prognostic indicators for all events. CONCLUSION: Myocardial ischaemia, in addition to glycaemic control, is a strong prognostic marker for asymptomatic patients with diabetic CKD who are scheduled to start haemodialysis. Stress MPI is highly recommended for the management and therapeutic stratification of such patients.
Assuntos
Complicações do Diabetes/diagnóstico , Complicações do Diabetes/terapia , Nefropatias/diagnóstico , Nefropatias/terapia , Diálise Renal , Estresse Fisiológico , Análise de Variância , Técnicas de Imagem de Sincronização Cardíaca , Doença Crônica/terapia , Complicações do Diabetes/complicações , Complicações do Diabetes/diagnóstico por imagem , Eletrocardiografia , Feminino , Humanos , Isquemia/diagnóstico por imagem , Isquemia/etiologia , Isquemia/fisiopatologia , Nefropatias/complicações , Nefropatias/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/etiologia , Infarto do Miocárdio/fisiopatologia , Imagem de Perfusão do Miocárdio , Prognóstico , Taxa de SobrevidaRESUMO
BACKGROUND: The 256-multislice CT (256MSCT) obtains volumetric data with 128-mm coverage in a single rotation. This coverage allows satisfactory visualization of the whole heart, allowing the 256MSCT to visualize the cardiac chambers and coronary arteries by cine scan without ECG gating. These characteristics provide a solution to the problems of MSCT. Although a wider beam width provides more efficient imaging over a wider coverage area, patient doses with the 256MSCT are of considerable concern. OBJECTIVE: We assessed potential radiation exposure with the 256MSCT in a cardiac CT protocol and compared the results to those with 16- and 64MSCT (collimated 64x0.5mm using 256MSCT). METHODS: Organ or tissue doses were measured in an anthropomorphic phantom under a coronary artery imaging protocol with the 256MSCT in cine scan mode without ECG gating, and with the 16- and 64MSCT in helical scan mode with ECG gating. RESULTS: Average effective doses were 22.8mSv for the 16MSCT, 27.8mSv for the 64MSCT and 14.1mSv for the 256MSCT. The 16- and 64MSCT doses were thus approximately 1.6- and 2.0-fold higher than those of the 256MSCT. CONCLUSIONS: Use of the 256MSCT in cardiac volumetric cine imaging offers lower radiation exposure than 16- and 64MSCT, and suggests the potential of this equipment in single-beat cardiac imaging without ECG gating. This effective dose is acceptable for routine cardiac imaging.
Assuntos
Angiografia Coronária/métodos , Doses de Radiação , Tomografia Computadorizada por Raios X/métodos , Humanos , Imagens de Fantasmas , Fatores de TempoRESUMO
OBJECTIVE: (201)Thallium (TL), (99m)Tc-tetrofosmin (TF), and (99m)Tc-sestamibi (MIBI) are extensively used as myocardial perfusion agents. The objective of the present study was to evaluate their kinetics under acute ischemia-reperfusion. METHODS: Isolated rat hearts, perfused by the Langendorff method at a constant flow rate of 10 ml/min, were allotted to normal control, mild ischemia, and severe ischemia groups, in which 20-min tracer wash-in was conducted followed by a 25-min tracer washout. No-flow ischemia (15 min for mild ischemia groups; 30 min for severe ischemia groups) was induced before conducting wash-in and washout in the ischemia groups. Whole-heart radioactivity was determined with an external gamma detector. Myocardial flow rate (K (1), ml/min) and clearance rate (k (2), min(-1)) were calculated. RESULTS: K (1TL), K (1TF), and K (1MIBI) decreased according to the severity of ischemia (K (1TL) 5.32 +/- 0.53, 4.76 +/- 0.70, and 1.44 +/- 0.59; K (1TF) 3.80 +/- 0.70, 2.73 +/- 0.99, and 1.09 +/- 0.45; and K (1MIBI) 3.45 +/- 1.10, 2.15 +/- 0.82, and 1.05 +/- 0.13, in the normal control, mild, and severe ischemia groups, respectively). K (1) was significantly higher for TL than for the (99m)Tc tracers (P < 0.05), but the (99m)Tc tracers had equivalent K (1) values. k (2TL) increased significantly (P < 0.05) in the ischemia groups (k (2TL) 0.062 +/- 0.013, 0.11 +/- 0.045, and 0.12 +/- 0.035), but showed no significant difference between the ischemia groups. k (2MIBI) and k (2TF) were significantly (P < 0.05) lower than k (2TL) and increased significantly (P < 0.05) in the severe ischemia group (k (2TF) 0.0056 +/- 0.0022, 0.0037 +/- 0.0015, and 0.024 +/- 0.015; and k (2MIBI) 0.00072 +/- 0.0011, 0.00038 +/- 0.00076, and 0.042 +/- 0.034). k (2MIBI) was significantly (P < 0.05) lower than k (2TF) in the normal control and mild ischemia groups. CONCLUSIONS: Tracer extraction was higher for TL than for the (99m)Tc tracers and all tracers decreased according to the severity of ischemia-reperfusion in the three tracer groups. The clearance kinetics of not only MIBI but also TF is possibly useful for the evaluation of the severity of ischemia, and the Langendorff method and a methodological approach by continuous determinations of radioactivity may serve for the quantitative analysis of tracer kinetic profiles.
Assuntos
Coração/diagnóstico por imagem , Miocárdio/patologia , Compostos Organofosforados/farmacologia , Compostos de Organotecnécio/farmacologia , Tecnécio Tc 99m Sestamibi/farmacologia , Radioisótopos de Tálio/farmacologia , Animais , Desenho de Equipamento , Cinética , Masculino , Perfusão , Cintilografia , Compostos Radiofarmacêuticos/uso terapêutico , Ratos , Ratos Wistar , Traumatismo por Reperfusão , Fatores de TempoRESUMO
Assessment of myocardial viability is very important for identifying patients likely to benefit from coronary revascularization. Clinical studies have shown that positron emission tomography(PET) using [18F] 2-fluoro-2deoxy-D-glucose (FDG) can accurately identify patients with viable myocardium that are likely to benefit from revascularization procedures, in terms of improvement of left ventricular (LV) function, alleviation of heart failure symptoms, and improvement of long-term prognosis. Single photon emission computed tomography (SPECT) using perfusion tracers such as TL-201 and Tc99m-MIBI are useful to assess viability, but a problem is their particularly low specificity. FDG-PET has several advantages including higher sensitivity and specificity over perfusion tracers. This article will review myocardial metabolism, FDG-PET protocol, procedures, interpretive criteria and clinical applications as well as problems and limitations. The literature regarding diagnostic and prognostic information about viability using FDG-PET is summarized.
Assuntos
Fluordesoxiglucose F18 , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/cirurgia , Miocárdio/metabolismo , Tomografia por Emissão de Pósitrons , Sobrevivência de Tecidos , Humanos , Masculino , Pessoa de Meia-Idade , Revascularização MiocárdicaRESUMO
OBJECTIVE: 11C-Methionine (MET) positron emission tomography (PET) imaging is a valuable technique for the evaluation of primary and recurrent brain tumors. Many studies have used MET-PET for data acquisition starting at 20 min after the tracer injection, while others have used scan initiation times at 5-15 min postinjection. No previous studies have identified the best acquisition timing during MET-PET imaging for suspected recurrent brain tumors. Here we sought to determine the optimal scan initiating timing after MET administration for the detection of recurrent brain tumors. MATERIALS AND METHODS: Twenty-three consecutive patients with suspected recurrent brain tumors underwent MET-PET examinations. Brain PET images were reconstructed from the four serial data sets (10-15, 15-20, 20-25, and 25-30 min postinjection) that were obtained using the list-mode acquisition technique. We determined the maximal standardized uptake values (SUVmax) of the target lesions and the target-to-normal-tissue ratios (TNRs), calculated as the SUVmax to the SUVmean of a region of interest placed on the normal contralateral frontal cortex. Target lesions without significant MET uptake were excluded. RESULTS: Thirty-one lesions from 23 patients were enrolled. There were no significant differences in MET SUVmax or TNR values among the PET images that were reconstructed with the data extracted from the four phases postinjection. CONCLUSION: The MET uptake in the suspected recurrent brain tumors was comparable among all data extraction time phases from 10 to 30 min postinjection. The scan initiation time of MET-PET at 10 min after the injection is allowable for the detection of recurrent brain tumors. The registration identification number of the original study is 1002.
Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Radioisótopos de Carbono/administração & dosagem , Metionina/administração & dosagem , Recidiva Local de Neoplasia/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Compostos Radiofarmacêuticos/administração & dosagem , Adulto , Idoso , Encéfalo/diagnóstico por imagem , Neoplasias Encefálicas/terapia , Diagnóstico Diferencial , Feminino , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Tempo , Carga TumoralRESUMO
AIMS: Cardiac sarcoidosis (CS) can be diagnosed using 18F-FDG-PET/CT (PET), cardiovascular magnetic resonance (CMR), and 123I-BMIPP/201TlCl dual myocardial SPECT. This study aims to clarify the relationships among the three modalities with respect to CS. METHODS AND RESULTS: We evaluated 16 patients (male n = 11; age 55 ± 13 years) with confirmed CS who underwent PET, CMR, and dual SPECT with gated SPECT before starting steroid therapy. The left ventricular myocardium was divided into 17 segments to obtain SUVmax for PET images, defect scores from 0 to 4 (0 normal; 4 absent), and mismatch scores for dual SPECT (BMDS, TLDS, and MS) images and late gadolinium enhancement (LGE) scores (0 none; 1 partly positive; 2 homogeneous) on CMR images. Summed BMDS, TLDS, and MS were 18.6 ± 12.6, 12.9 ± 10.9, and 5.7 ± 3.1, respectively. The segmental BMDS and TLDS scores became significantly higher as the LGE scores increased. The MS scores were significantly higher in areas of LGE with a score of 1 than 0 (both, p < 0.001), but did not significantly differ between areas with LGE scores of 1 and 2. The SUVmax was significantly higher in LGE areas with a score of 1 than 0 (p < 0.025), but did not significantly differ between those with scores of 1 or 2. CONCLUSION: Regions with a higher SUVmax indicating active myocardial inflammation were mainly located in areas with LGE, where BMIPP and TL mismatches were evident in patients with CS.
Assuntos
Cardiomiopatias/diagnóstico por imagem , Imageamento por Ressonância Magnética , Imagem Multimodal , Miocardite/diagnóstico por imagem , Sarcoidose/diagnóstico por imagem , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada por Raios X , Adulto , Idoso , Cardiomiopatias/imunologia , Meios de Contraste , Ácidos Graxos , Feminino , Fluordesoxiglucose F18 , Gadolínio , Coração/diagnóstico por imagem , Humanos , Iodobenzenos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Imagem Multimodal/métodos , Miocárdio/imunologia , Miocárdio/patologia , Compostos Radiofarmacêuticos , Estudos Retrospectivos , Sarcoidose/imunologia , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto JovemRESUMO
IQ·SPECT (Siemens Medical Solutions) is a solution for high-sensitivity and short-time acquisition imaging of the heart for a variable angle general purpose gamma camera. It consists of a multi-focal collimator, a cardio-centric orbit and advanced iterative reconstruction, modeling the image formation physics accurately. The multi-focal collimator enables distance-dependent enlargement of the center region while avoiding truncation at the edges. With the specified configuration and a cardio-centric orbit it can obtain a fourfold sensitivity increase for the heart at the center of the scan orbit. Since IQ·SPECT shows characteristic distribution patterns in the myocardium, appropriate acquisition and processing conditions are required, and normal databases are convenient for quantification of both normal and abnormal perfusion images. The use of prone imaging can be a good option when X-ray computed tomography (CT) is not available for attenuation correction. CT-based attenuation correction changes count distribution significantly in the inferior wall and around the apex, hence image interpretation training and additional use of normal databases are recommended. Recent reports regarding its technology, Japanese Society of Nuclear Medicine working group activities, and clinical studies using 201Tl and 99mTc-perfusion tracers in Japan are summarized.
Assuntos
Bases de Dados Factuais , Estudos Multicêntricos como Assunto , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Humanos , Processamento de Imagem Assistida por Computador , Imagem de Perfusão do MiocárdioRESUMO
UNLABELLED: Benign and malignant pulmonary lesions usually are differentiated by 18F-FDG PET with a semiquantitative 18F-FDG standardized uptake value (SUV) of 2.5. However, the frequency of malignancies with an SUV of <2.5 is significant, and pulmonary nodules with low 18F-FDG uptake often present diagnostic challenges. METHODS: Among 360 consecutive patients who underwent 18F-FDG PET to evaluate pulmonary nodules found on CT, we retrospectively analyzed 43 who had solid pulmonary lesions (excluding lesions with ground-glass opacity, infiltration, or benign calcification) with an SUV of <2.5. The uptake of 18F-FDG was graded by a visual method (absent, faint, moderate, or intense) and 2 semiquantitative methods (SUV and contrast ratio [CR]). Final classification was based on histopathologic findings or at least 6 mo of clinical follow-up. RESULTS: We found 16 malignant (diameter, 8-32 mm) and 27 benign (7-36 mm) lesions. When faint visual uptake was the cutoff for positive 18F-FDG PET results, the receiver-operating-characteristic (ROC) analysis correctly identified all 16 malignancies and yielded false-positive results for 10 of 27 benign lesions. Sensitivity was 100%, specificity was 63%, and the positive and negative predictive values were 62% and 100%, respectively. When an SUV of 1.59 was the cutoff for positive 18F-FDG PET results, the ROC analysis revealed 81% sensitivity, 85% specificity, and positive and negative predictive values of 77% and 89%, respectively. At a cutoff for positive 18F-FDG PET results of a CR of 0.29, the ROC analysis revealed 75% sensitivity, 82% specificity, and positive and negative predictive values of 71% and 85%, respectively. The areas under the curve in ROC analyses did not differ significantly among the 3 analyses (visual, 0.84; SUV, 0.81; and CR, 0.82). Analyses of intra- and interobserver variabilities indicated that visual and SUV analyses were quite reproducible, whereas CR analysis was poorly reproducible. CONCLUSION: These results suggested that for solid pulmonary lesions with low 18F-FDG uptake, semiquantitative approaches do not improve the accuracy of 18F-FDG PET over that obtained with visual analysis. Pulmonary lesions with visually absent uptake indicate that the probability of malignancies is very low. In contrast, the probability of malignancy in any visually evident lesion is about 60%.
Assuntos
Fluordesoxiglucose F18 , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Tomografia por Emissão de Pósitrons/métodos , Nódulo Pulmonar Solitário/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Fluordesoxiglucose F18/farmacocinética , Humanos , Interpretação de Imagem Assistida por Computador/normas , Neoplasias Pulmonares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Tomografia por Emissão de Pósitrons/normas , Compostos Radiofarmacêuticos/farmacocinética , Reprodutibilidade dos Testes , Estudos Retrospectivos , Sensibilidade e EspecificidadeRESUMO
RATIONALE AND OBJECTIVES: To improve effective scan time and image quality in cone-beam computed tomography (CT), Parker's weighting function (half scan [HS]-Feldkamp-Davis-Kress [FDK]) extended to a larger range up to 2pi was proposed as new half-scan algorithm (NHS-FDK). We conducted a practical physical evaluation of NHS-FDK and HS-FDK using 256-detector row CT. MATERIALS AND METHODS: Three types of weighting function (full-scan [FS-FDK], HS-FDK, and NHS-FDK) were evaluated by using 256-detector row CT for five variables, ie, point spread function, image noise, CT number uniformity, Feldkamp artifact, temporal resolution, and clinical evaluation. RESULTS: Image noise, Feldkamp artifact, and temporal resolution were dependent on weighting function. Image noise magnitude was independent of projection angle for all regions of interest with FS-FDK, but showed a symmetric pattern with projection angle with HS-FDK and NHS-FDK. With regard to temporal resolution, NHS-FDK did not remove the motion artifact in the heart except in such slower motion organs as the pulmonary vessels, whereas HS-FDK reduced the motion artifact in the heart. HS-FDK had an even more incomplete data region in the Radon space than FS-FDK, suggesting that it would provide poor image quality distant to the midplane in the longitudinal direction. In practical testing in human subjects, HS-FDK showed inferior performance in all variables except temporal resolution. CONCLUSION: Despite its inferiority to FS-FDK for static objects, HS-FDK may be useful in chest imaging. Contrary to previous findings using static images, NHS-FDK failed to show advantages over HS-FDK or FS-FDK in a moving phantom and human subjects.
Assuntos
Algoritmos , Artefatos , Imageamento Tridimensional/métodos , Armazenamento e Recuperação da Informação/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Masculino , Pessoa de Meia-Idade , Imagens de Fantasmas , Intensificação de Imagem Radiográfica/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X/instrumentação , Transdutores , Gravação em Vídeo/métodosRESUMO
Obstructive sleep apnea syndrome (OSAS) is a group of disorders in which breathing stops intermittently and repeatedly for 10 seconds or more during sleep. The causal site of the disorders is thought to be in the upper airway above the glottis. In order to understand the three-dimensional features of the oral and peripharyngeal structures involved in the disorders, we calculated the tongue volume/oral cavity volume ratio (TV/OCV ratio) in the oral cavity using magnetic resonance imaging (MRI) for both OSAS patients and normal controls. The study subjects comprised 20 male patients with OSAS (apnea-hypopnea index [AHI] > or = 5.0, with a diagnosis of OSAS) and 20 normal male adults (AHI<5.0, with no history of OSAS) as the controls. We performed MRI to acquire T1- and T2-weighted images. We estimated tongue volumes on the basis of the cross-sectional area of each image, then using the tongue volume data, we calculated TV/OCV ratios. In the normal control group, mean (+/- SD) body mass index (BMI) was 21.68 +/- 1.73 and the mean TV/OCV ratio was 86.98 +/- 3.16%, whereas these values were 25.0 +/- 15.94 and 90.56 +/- 2.15%, respectively, in the OSAS patient group. The TV/OCV ratio of the OSAS patient group was significantly higher than that of the normal control group (p<0.01).
Assuntos
Imageamento por Ressonância Magnética , Boca/patologia , Apneia Obstrutiva do Sono/patologia , Língua/patologia , Adulto , Anatomia Transversal , Índice de Massa Corporal , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Palato Mole/patologia , PolissonografiaRESUMO
BACKGROUND: In patients with small hearts, the Quantitative Gated single-photon emission computed tomography (SPECT) (QGS) program frequently underestimates the left ventricular (LV) end-systolic volume (ESV) and overestimates the ejection fraction (EF). A newly developed cardiac software program, cardioREPO/EXINI heart (cREPO), has been proposed to more accurately quantify small hearts using active shape modeling and a volume-dependent edge correction algorithm for LV delineation. The aim of this study was to validate cREPO in vivo for measuring the LV volumes and EF of both small and non-small hearts, in comparison with values obtained via cardiac MRI (CMR). METHODS: We performed stress (99m)Tc-MIBI SPECT and CMR within a 30-day interval for 44 patients (mean age, 66 years; 27 men). Resting EF, end-diastolic volume (EDV), and ESV with QGS and cREPO were compared with values obtained via CMR. RESULTS: The subjects consisted of 17 small and 27 non-small hearts. CMR yielded EDV, ESV, and EF values of 135 ± 31 ml (mean ± SD, range 85-217 ml), 57 ± 21 ml (27-105 ml), and 60 ± 6 % (45-70 %), respectively. Compared with CMR, both QGS and cREPO systematically underestimated both EDV and ESV and overestimated EF. The magnitude of the overestimation of EF by QGS, compared with CMR, correlated strongly with the given EF values (r = 0.71, P < 0.0001). In contrast, no significant correlation was seen with cREPO (r = 0.18, P = 0.24). In addition, no significant correlation was found between the magnitude of the underestimation of ESV and heart size with cREPO (r = 0.03, P = 0.83). Thus, cREPO provided a relatively constant 9 % overestimation of EF values relative to CMR, for the studied EF range for both small and non-small hearts. CONCLUSIONS: The use of the new algorithm of cREPO ameliorated exaggerated EF in small hearts but not resolved completely. The program provided a constant 9 % overestimation for both small and non-small hearts, which should be carefully taken into account for clinical assessment of LV function.
RESUMO
Ghrelin is a novel growth hormone-releasing peptide isolated from human and rat stomach that induces weight gain by increasing food intake and reducing fat utilization. Although recent data indicate that ghrelin is downregulated in human adult obesity, the characteristics of human obesity are heterogeneous, especially in children and adolescents, and depend on the distribution of subcutaneous and visceral fat tissue. We measured fasting plasma ghrelin concentrations by radioimmunoassay in 49 obese Japanese children and adolescents (38 boys and 11 girls; mean age 10.2 +/- 2.8 years; BMI 28.0 +/- 4.5 kg/m(2), percent overweight 56.0 +/- 20.7%), and analyzed associations of their ghrelin concentrations with their body composition, insulin resistance, and adipocytokine concentrations. Fasting plasma ghrelin levels were negatively correlated with BMI and waist circumference, but not with percent overweight or percent body fat, whereas fasting leptin levels were positively correlated with all of the following parameters: BMI, waist circumference, percent overweight, and percent body fat. Plasma ghrelin levels were negatively correlated with fasting immunoreactive insulin, homeostasis model assessment insulin resistance index, and quantitative insulin sensitivity check index values. There was no correlation between plasma ghrelin and leptin, but ghrelin was negatively correlated with the PAI-1 concentrations. The results suggest that the downregulation of ghrelin secretion may be a consequence of higher insulin resistance associated with visceral fat accumulation and elevated PAI-1 concentrations, and not a consequence of total body fat accumulation associated with elevated leptin concentrations.
Assuntos
Jejum/sangue , Resistência à Insulina/fisiologia , Obesidade/sangue , Obesidade/fisiopatologia , Hormônios Peptídicos/sangue , Inibidor 1 de Ativador de Plasminogênio/sangue , Adolescente , Adulto , Composição Corporal , Criança , Feminino , Grelina , Humanos , Leptina/sangue , Masculino , Obesidade/patologiaRESUMO
OBJECTIVES: To compare the differences of visceral anomalies shown by computed tomography (CT) in patients with polysplenia syndrome (PS) or asplenia syndrome (AS). METHODS: This retrospective study was approved by the institutional review board, and informed consent was waived. Thirty-one patients with PS and 29 patients with AS underwent chest-abdominal CT. The evaluated CT findings were as follows: the orientation of stomach, liver and gallbladder; short pancreas; azygous/hemiazygous continuation; ipsilateral position of the inferior vena cava and aorta; preduodenal portal vein; abnormal confluence of renal vein (defined as renal vein drains to the inferior vena cava or azygous/hemiazygous vein at the upper level of celiac trunk origin); gastrointestinal malrotation; and tracheobronchial tree. RESULTS: Azygous/hemiazygous continuation was seen in 74% (20 of 27)/0% (0 of 28) of PS/AS (P<0.0001), bilateral hyparterial bronchi in 75% (24 of 32)/5% (1 of 22), bilateral eparterial bronchi in 9% (3 of 32)/95% (21 of 22), ipsilateral position of the inferior vena cava and aorta in 59% (16 of 27)/89% (25 of 28), and abnormal confluence of renal vein in 7% (2 of 27)/57% (16 of 28), respectively. No significant differences were found in the other anomalies. CONCLUSION: Significant differences in anomalous systemic venous connections and tracheobronchial anomaly were observed between PS and AS. Abnormal confluence of renal vein is relatively rare anomalous venous connections, but frequently observed in AS.
Assuntos
Síndrome de Heterotaxia/diagnóstico por imagem , Baço/anormalidades , Baço/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adolescente , Adulto , Veia Ázigos/diagnóstico por imagem , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Fígado/diagnóstico por imagem , Masculino , Pâncreas/diagnóstico por imagem , Veia Porta/diagnóstico por imagem , Veias Renais/anormalidades , Veias Renais/diagnóstico por imagem , Estudos Retrospectivos , Estômago/diagnóstico por imagem , Veia Cava Inferior/diagnóstico por imagem , Adulto JovemRESUMO
AIM: [(18)F]Fluorodeoxyglucose positron-emission tomography with computed tomography ((18)F-FDG-PET/CT) was assessed regarding its utility in prediction of outcomes after curative resection of colorectal cancer. PATIENTS AND METHODS: Preoperative (18)F-FDG-PET/CT was performed in 325 patients with colorectal cancer. Maximum standardized uptake value (SUVmax), mean SUV (SUVmean), metabolic volume (MV), and total lesion glycolysis (TLG) were measured. Patients were divided into groups using cut-offs for overall survival (OS). (18)F-FDG-PET/CT parameters and other clinicopathological factors were investigated as prognostic factors. RESULTS: The 5-year OS rates in the low and high SUVmax, SUVmean, MV, and TLG groups were 91.4% and 87.0% (p=0.238), 90.8% and 88.2% (p=0.453), 91.7% and 83.8% (p=0.006), and 92.1% and 70.1% (p=0.001), respectively, indicating poorer outcomes in patients with high MV and TLG. In multivariate analysis, high TLG, age ≥65 years, rectal tumor location, and pN(+) were independent factors predicting a poor prognosis. CONCLUSION: TLG in (18)F-FDG-PET/CT is a prognostic parameter for colorectal cancer after curative resection.
Assuntos
Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/cirurgia , Glicólise , Prognóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/patologia , Feminino , Fluordesoxiglucose F18 , Humanos , Masculino , Pessoa de Meia-Idade , Imagem Multimodal , Estadiamento de Neoplasias , Tomografia por Emissão de Pósitrons , Modelos de Riscos Proporcionais , Análise de Sobrevida , Tomografia Computadorizada por Raios XRESUMO
PURPOSE: The aim of this multi-center study was to assess the diagnostic capability of visual assessment in L-methyl-11C-methionine positron emission tomography (MET-PET) for differentiating a recurrent brain tumor from radiation-induced necrosis after radiotherapy, and to compare it to the accuracy of quantitative analysis. METHODS: A total of 73 brain lesions (glioma: 31, brain metastasis: 42) in 70 patients who underwent MET-PET were included in this study. Visual analysis was performed by comparison of MET uptake in the brain lesion with MET uptake in one of four regions (around the lesion, contralateral frontal lobe, contralateral area, and contralateral cerebellar cortex). The concordance rate and logistic regression analysis were used to evaluate the diagnostic ability of visual assessment. Receiver-operating characteristic curve analysis was used to compare visual assessment with quantitative assessment based on the lesion-to-normal (L/N) ratio of MET uptake. RESULTS: Interobserver and intraobserver κ-values were highest at 0.657 and 0.714, respectively, when assessing MET uptake in the lesion compared to that in the contralateral cerebellar cortex. Logistic regression analysis showed that assessing MET uptake in the contralateral cerebellar cortex with brain metastasis was significantly related to the final result. The highest area under the receiver-operating characteristic curve (AUC) with visual assessment for brain metastasis was 0.85, showing no statistically significant difference with L/Nmax of the contralateral brain (AUC = 0.89) or with L/Nmean of the contralateral cerebellar cortex (AUC = 0.89), which were the areas that were the highest in the quantitative assessment. For evaluation of gliomas, no specific candidate was confirmed among the four areas used in visual assessment, and no significant difference was seen between visual assessment and quantitative assessment. CONCLUSION: The visual assessment showed no significant difference from quantitative assessment of MET-PET with a relevant cut-off value for the differentiation of recurrent brain tumors from radiation-induced necrosis.