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BACKGROUND: Mammography screening programs (MSP) have shown that breast cancer can be detected at an earlier stage enabling less invasive treatment and leading to a better survival rate. The considerable numbers of interval breast cancer (IBC) and the additional examinations required, the majority of which turn out not to be cancer, are critically assessed. OBJECTIVE: In recent years companies and universities have used machine learning (ML) to develop powerful algorithms that demonstrate astonishing abilities to read mammograms. Can such algorithms be used to improve the quality of MSP? METHOD: The original screening mammographies of 251 cases with IBC were retrospectively analyzed using the software ProFound AI® (iCAD) and the results were compared (case score, risk score) with a control group. The relevant current literature was also studied. RESULTS: The distributions of the case scores and the risk scores were markedly shifted to higher risks compared to the control group, comparable to the results of other studies. CONCLUSION: Retrospective studies as well as our own data show that artificial intelligence (AI) could change our approach to MSP in the future in the direction of personalized screening and could enable a significant reduction in the workload of radiologists, fewer additional examinations and a reduced number of IBCs; however, the results of prospective studies are needed before implementation.
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OBJECTIVES: Computed tomography based navigation for endoscopic sinus surgery is inflationary used despite of major public concern about iatrogenic radiation induced cancer risk. Studies on dose reduction for CAS-CT are almost nonexistent. We validate the use of radiation dose reduced CAS-CT for clinically applied surface registration. METHODS: Dose reduced CAS-CT of mineral salt fixed, human cadaver heads with 9.6, 6, 4, 2 and 1.1 mGy were compared with the reference dose at 65 mGy CTDI (CT-Dose Index). For each CT dose with different surface resolution, the precision of the soft touch registration was measured with target registration error (TRE). In a practical step, dose reduced protocols were tested for 12 months. RESULTS: Using surface registration at highest and lowest doses, TRE did not differ significantly for registration accuracy. Protocols tested preserved technical registration accuracy and the pragmatics of dose reduction was limited only by different needs for picture quality of the individual surgeon, use for uncomplicated or revision surgery, and reserve for other unexpected factors (movement artifacts). CONCLUSIONS: The accuracy of today's surface registration technology was not the limit for dose reduction. It is the amount of diminished picture quality tolerated by the individual surgeon and the question of how much of the ever refined radiological picture resolution is necessary at all. For the majority of operations, consensus for a significant 6-fold radiation dose reduction from 65 mGy to 9.6 mGy CTDI could be realized illustrating a big potential for similar approaches in other institutions.
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Senos Craneales/diagnóstico por imagen , Senos Craneales/cirugía , Neuronavegación/métodos , Cadáver , Endoscopía , Humanos , Dosis de Radiación , Cirugía Asistida por Computador , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND AND PURPOSE: Computer-assisted navigation is increasingly used in functional endoscopic sinus surgery (FESS) to prevent injury to vital structures, necessitating preparative CT and, thus, radiation exposure. The purpose of our study was to investigate currently used radiation doses for CT in computer-assisted navigation in sinus surgery (CAS-CT) and to assess minimal doses required. MATERIALS AND METHODS: A questionnaire inquiring about dose parameters used for CAS-CT was sent to 30 radiologic institutions. The feasibility of low-dose registration was tested with a phantom. The influence of CAS-CT dose on technical accuracy and on the practical performance of 5 ear, nose, and throat (ENT) surgeons was evaluated with cadaver heads. RESULTS: The questionnaire response rate was 63%. Variation between minimal and maximal dose used for CAS-CT was 18-fold. Phantom registration was possible with doses as low as 1.1 mGy. No dose dependence on technical accuracy was found. ENT surgeons were able to identify anatomic landmarks on scans with a dose as low as 3.1 mGy. CONCLUSIONS: The vast dose difference between institutions mirrors different attitudes toward image quality and radiation-protection issues rather than being technically founded, and many patients undergo CAS-CT at higher doses than necessary. The only limit for dose reduction in CT for computer-assisted endoscopic sinus surgery is the ENT surgeon's ability to cope with impaired image quality, whereas there is no technically justified lower dose limit. We recommend, generally, doses used for the typical diagnostic low-dose sinus CT (120 kV/20-50 mAs). When no diagnostic image quality is needed, even a reduction down to a third is possible.
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Senos Craneales/diagnóstico por imagen , Senos Craneales/cirugía , Endoscopía , Neuronavegación/métodos , Planificación de la Radioterapia Asistida por Computador/métodos , Cadáver , Estudios de Factibilidad , Encuestas de Atención de la Salud , Humanos , Fantasmas de Imagen , Dosis de Radiación , Radiografía , Encuestas y CuestionariosRESUMEN
OBJECTIVE: Several factors influence whether individuals with affective disorders seek help. The Zurich cohort study provides an opportunity to explore patient-based factors without confounding with problems of access. This study aims to identify features which predict help-seeking behaviour in symptomatic individuals and to explore failure of help seeking in those who did not. METHOD: Characteristics of currently symptomatic 40-year-old individuals in a stratified epidemiological sample were tested against help-seeking behaviour using bivariate statistics and logistic regression. Individual predictors were identified and interaction effects tested. RESULTS: Thirty-one per cent of the 364 subjects sought help in the preceding year. Past treatment and living alone were significantly associated with treatment. Total number of symptoms and several individual symptoms correlated with treatment in the bivariate analyses but regression analysis identified "unfounded self-reproach" and "hopelessness" interacting with social support to predict the best treatment. CONCLUSION: Social support is strongly protective against needing help in the presence of distressing affective symptoms unless these symptoms become elaborated into conclusions about their meaning and prognostic significance.
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Síntomas Afectivos/psicología , Aceptación de la Atención de Salud/psicología , Adulto , Síntomas Afectivos/epidemiología , Estudios de Cohortes , Estudios Epidemiológicos , Femenino , Humanos , Masculino , Análisis Multivariante , Apoyo Social , Suiza/epidemiologíaRESUMEN
Many randomized trials have shown aspirin as an effective antiplatelet drug for the secondary prevention of cardiovascular events. The NNT (number needed to treat) to prevent 1 vascular event is about 25. The NNH (number needed to harm) inducing one cerebral bleeding is about 1'000, to provoke one severe extracerebral bleeding about 100-200. The primary prevention can be recommended only for high risk patients for cardiovascular events (annual risk of 1-1.5% or more), calculated on the basis of the Framingham data, the Sheffield tables or in analysis of U.S. Preventive Services Task Force. The mechanisms of action, interactions and the "aspirin-resistance" are briefly discussed.
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Aspirina/uso terapéutico , Fibrinolíticos/uso terapéutico , Inhibidores de Agregación Plaquetaria/uso terapéutico , Administración Oral , Adulto , Factores de Edad , Anciano , Anticoagulantes/administración & dosificación , Anticoagulantes/uso terapéutico , Aspirina/administración & dosificación , Aspirina/efectos adversos , Enfermedades Cardiovasculares/prevención & control , Complicaciones de la Diabetes , Diabetes Mellitus/tratamiento farmacológico , Interacciones Farmacológicas , Quimioterapia Combinada , Femenino , Fibrinolíticos/administración & dosificación , Fibrinolíticos/efectos adversos , Hemorragia/inducido químicamente , Humanos , Masculino , Inhibidores de Agregación Plaquetaria/administración & dosificación , Inhibidores de Agregación Plaquetaria/efectos adversos , Prevención Primaria , Ensayos Clínicos Controlados Aleatorios como Asunto , Factores de Riesgo , Factores de TiempoRESUMEN
UNLABELLED: Perturbation of respiratory mechanics produced by general anesthesia and surgery is more pronounced in morbidly obese (MO) patients. Because general anesthesia induces pulmonary atelectasis in nonobese patients, we hypothesized that atelectasis formation would be particularly significant in MO patients. We investigated the importance and resorption of atelectasis after general anesthesia in MO and nonobese patients. Twenty MO patients were anesthetized for laparoscopic gastroplasty and 10 nonobese patients for laparoscopic cholecystectomy. We assessed pulmonary atelectasis by computed tomography at three different periods: before the induction of general anesthesia, immediately after tracheal extubation, and 24 h later. Already before the induction of anesthesia, MO patients had more atelectasis, expressed in the percentage of the total lung area, than nonobese patients (2.1% versus 1.0%, respectively; P < 0.01). After tracheal extubation, atelectasis had increased in both groups but remained significantly more so in the MO group (7.6% for MO patients versus 2.8% for the nonobese; P < 0.05). Twenty-four hours later, the amount of atelectasis remained unchanged in the MO patients, but we observed a complete resorption in nonobese patients (9.7% versus 1.9%, respectively; P < 0.01). General anesthesia in MO patients generated much more atelectasis than in nonobese patients. Moreover, atelectasis remained unchanged for at least 24 h in MO patients, whereas atelectasis disappeared in the nonobese. IMPLICATIONS: We compared the resolution over time of pulmonary atelectasis after a laparoscopic procedure by performing computed tomography scans in two different groups of patients: 1 group had 10 nonobese patients, and in the other group there were 20 morbidly obese patients.
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Complicaciones Intraoperatorias/etiología , Obesidad Mórbida/complicaciones , Complicaciones Posoperatorias/etiología , Atelectasia Pulmonar/etiología , Adulto , Femenino , Humanos , Laparoscopía , Masculino , Persona de Mediana EdadRESUMEN
OBJECTIVE: The aim of the Vocational Rehabilitation Center in Zurich (VRC) is to reintegrate mentally ill persons into the primary labour market, mainly by prevocational training followed by continuous professional support for employed individuals. The present study evaluated the impact of the VRC. METHODS: The job and financial situation of 68 trained persons was assessed up to two years after the training. Additionally, their vocational history and sociodemographic data were analysed. RESULTS: Before the training, only 9 % had a job, while two years after the course 42 % were employed in competitive jobs. On the other hand, using an ordinal scale, two years after the training, 78 % of the patients were found in a better job situation than before the course. Likewise, the financial situation of 52 % of the clients has improved within those two years. The strongest correlation with success was the intensity of support after the training. CONCLUSIONS: The VCR is effective in training mentally ill patients for the primary job market. Continuous professional support is vital for ongoing success.
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Empleos Subvencionados , Trastornos Mentales/rehabilitación , Rehabilitación Vocacional/estadística & datos numéricos , Adulto , Femenino , Humanos , Masculino , Satisfacción del Paciente , Evaluación de Programas y Proyectos de Salud , Rehabilitación Vocacional/métodos , Estudios Retrospectivos , Factores Socioeconómicos , Encuestas y Cuestionarios , Suiza , Factores de TiempoRESUMEN
AIMS: To assess the impact of the closure of an open drug scene on the demand for methadone maintenance treatment (MMT). DESIGN: Interrupted time series analysis of case register-based data of all MMTs performed in the canton of Zurich (Switzerland) between June 16 1992 and July 7 1997. SETTING: Five private and 14 state-controlled institutions as well as 330 general practitioners, 35 psychiatrists, and 79 other specialists offering outpatient MMT. PARTICIPANTS: 5210 opiate users with 9042 MMT episodes. MEASUREMENTS: Monthly number of entries into MMT before, during and after the closure of the Letten scene in February 1995, MMT retention rates, participants' socio-demographic and drug-related data. FINDINGS: ARIMA modelling revealed 68 (95% CI = 31-105; p < 0.001) additional MMT admissions due to the dispersion of the open drug scene without a decrease in MMT retention rates. Socio-demographic and drug-related characteristics of patients entering MMT in the month of the closure did not significantly differ from other admissions. CONCLUSIONS: Law enforcement strategies to eliminate open drug scenes may increase the demand for MMT. Sufficient treatment facilities for opioid dependence should be provided when law enforcement activities against open drug scenes are planned.
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Necesidades y Demandas de Servicios de Salud , Drogas Ilícitas/legislación & jurisprudencia , Metadona/provisión & distribución , Narcóticos/provisión & distribución , Trastornos Relacionados con Opioides/rehabilitación , Centros de Tratamiento de Abuso de Sustancias/estadística & datos numéricos , Adulto , Femenino , Humanos , Masculino , SuizaRESUMEN
In psychiatric treatment, differences between therapists' observer ratings and patients' self-ratings are well known. We studied these differences in a sample of chronically mentally ill outpatients. The results show that the patients rated their psychosocial status significantly better than their therapists. By means of multiple regression analysis, we designed a model to explain the specific differences. By placing more emphasis on leisure activities and less emphasis on addictive behavior, compliance, and psychopathology, therapists might predict global ratings given by patients more accurately. This model helps therapists obtain a better understanding of their patients.
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Atención Ambulatoria , Actitud del Personal de Salud , Estado de Salud , Trastornos Mentales/psicología , Trastornos Mentales/terapia , Calidad de Vida , Adulto , Actitud Frente a la Salud , Femenino , Humanos , Masculino , Trastornos Mentales/diagnóstico , Relaciones Médico-Paciente , Escalas de Valoración Psiquiátrica/estadística & datos numéricos , Análisis de RegresiónRESUMEN
The epidermal growth factor receptor family consists of four closely related transmembrane receptors: epidermal growth factor receptor (EGF-R), c-erbB-2, c-erbB-3, and c-erbB-4. Overexpression of each receptor may lead to cell transformation and contributes to tumor progression in various malignancies. Although these factors have been analyzed in many cancers separately, little is known about their concomitant expression in esophageal cancer. Based on the finding that EGF-R and c-erbB-2 form highly active transmembranous heterodimers that enhance cell growth and proliferation, we used Northern blot analysis and immunohistochemistry to analyze the concomitant expression of EGF-R, c-erbB-2, and c-erbB-3 in tissue samples obtained from 39 patients undergoing esophagectomy for esophageal cancer. Northern blot analysis revealed a fourfold increase (p < 0.01) in EGF-R mRNA levels in the esophageal cancer samples in comparison with normal tissue samples. The c-erbB-2 receptor was only 1.25-fold elevated in the esophageal cancers, which failed to be statistically significant (p = 0.31). In contrast, c-erbB-3 mRNA levels were 3.5-fold lower (p < 0.01) in the esophageal cancers than in the normal tissues. Immunohistochemical analysis showed weak EGF-R, c-erbB-2, and c-erbB-3 immunostaining in the normal esophageal tissue. In esophageal cancer samples, immunoreactivity for EGF-R, c-erbB-2, and c-erbB-3 was mainly located in the cancer cells. Strong EGF-R, c-erbB-2, and c-erbB-3 immunoreactivity was present in 59%, 64%, and 64% of the esophageal cancer samples, respectively. In consecutive tissue sections, identical cancer cell clusters often exhibited these three closely related receptors simultaneously. However, correlation of the immunohistochemical findings with the clinicopathologic patient parameters revealed that the presence of EGF-R, c-erbB-2, or c-erbB-3 had no influence on patient survival (p > 0.05). In addition, the simultaneous presence of these receptors did not influence survival. Our findings indicate that in esophageal cancer the presence of EGF-R, c-erbB-2, and c-erbB-3 alone or in combination seems to have no major influence on patient prognosis and does not alter tumor growth behavior significantly.
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Adenocarcinoma/genética , Carcinoma de Células Escamosas/genética , Receptores ErbB/genética , Neoplasias Esofágicas/genética , Receptor ErbB-2/genética , Receptor ErbB-3/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Adulto , Anciano , Anciano de 80 o más Años , Northern Blotting , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Receptores ErbB/biosíntesis , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/patología , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Técnicas para Inmunoenzimas , Masculino , Persona de Mediana Edad , Pronóstico , ARN Mensajero/metabolismo , ARN Neoplásico/genética , Receptor ErbB-2/biosíntesis , Receptor ErbB-3/biosíntesisRESUMEN
PURPOSE: To establish the value of computed tomography (CT) and magnetic resonance imaging (MRI) in predicting bladder and rectum involvement in uterine carcinoma. MATERIAL AND METHODS: 6 different imaging signs (focal obliteration of perivesical or perirectal fat planes, area and angle of contact between uterus and bladder or rectum, asymmetric bladder or rectum wall thickening, evidence of intraluminal masses, and signal intensity of bladder or rectum wall on T2-weighted or contrast-enhanced MR images) were analysed retrospectively in 129 patients who underwent 92 CT and/or 64 MRI examinations. The data were correlated with intraoperative findings and the results of cystoscopy and rectoscopy. RESULTS: Asymmetric wall thickening, evidence of intraluminal masses and increased signal intensities of the bladder wall or rectum wall were valuable signs of infiltration (sensitivity 71-100%, specificity 91-96% and accuracy 89-97%). In 27 patients submitted to both imaging examinations MRI was somewhat superior compared to CT (p > 0.1) and yielded similar results as endoscopic procedures (accuracy of cystoscopy and rectoscopy of 90% and 94%, respectively). CONCLUSION: CT and MRI allow to predict involvement of bladder or rectum wall in carcinoma of the uterus with a similar accuracy as endoscopic procedures.
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Imagen por Resonancia Magnética , Neoplasias del Recto/diagnóstico , Tomografía Computarizada por Rayos X , Neoplasias de la Vejiga Urinaria/diagnóstico , Neoplasias Uterinas/diagnóstico , Anciano , Femenino , Humanos , Imagen por Resonancia Magnética/instrumentación , Imagen por Resonancia Magnética/métodos , Imagen por Resonancia Magnética/estadística & datos numéricos , Persona de Mediana Edad , Invasividad Neoplásica , Neoplasias del Recto/patología , Reproducibilidad de los Resultados , Estudios Retrospectivos , Sensibilidad y Especificidad , Tomografía Computarizada por Rayos X/instrumentación , Tomografía Computarizada por Rayos X/métodos , Tomografía Computarizada por Rayos X/estadística & datos numéricos , Neoplasias de la Vejiga Urinaria/patología , Neoplasias Uterinas/patologíaRESUMEN
Dividing the delivery system of larger psychiatric hospitals into defined smaller catchment areas called sectors, implies a contribution to quality assurance. Continuous monitoring and evaluation of a period before and after this reorganisation, which took place in 1994 for the central region of Zürich (Psychiatric University Hospital), allows perception of expected and possible unexpected changes. All newly registered patients were recorded within a time span divided into five periods of six month five each, the last one covering the first six months after sectorisation. This design permits to answer the question as to how fast the intended changes after sectorisation occur, and also to control side effects. Results show that sectorisation resulted in a marked increase of registrations from the defined catchment area of each sector, and that the investigated institutions achieve attainment of the aim to effect a special selection of psychiatric patients characterised by considerable psycho-social deficits. The two sectors display differences in respect of socio-demographic characteristics of newly registered patients.
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Áreas de Influencia de Salud , Servicios Comunitarios de Salud Mental/organización & administración , Atención Ambulatoria/organización & administración , Atención Ambulatoria/estadística & datos numéricos , Áreas de Influencia de Salud/estadística & datos numéricos , Servicios Comunitarios de Salud Mental/estadística & datos numéricos , Atención a la Salud/organización & administración , Atención a la Salud/estadística & datos numéricos , Femenino , Hospitales Psiquiátricos/organización & administración , Hospitales Psiquiátricos/estadística & datos numéricos , Hospitales Universitarios/organización & administración , Hospitales Universitarios/estadística & datos numéricos , Humanos , Masculino , Evaluación de Programas y Proyectos de Salud/estadística & datos numéricos , Suiza , Factores de TiempoRESUMEN
Although the clinical manifestations of Valsalva's maneuver are well known, the associated hemodynamic changes in the great vessels have not been extensively studied and documented. In each of six healthy subjects, we evaluated three "quasi-steady-state" phases of Valsalva's maneuver: (1) during normal respiration, (2) during late strain, and (3) 4 seconds after strain release. Continuous flow, velocity, and cross-sectional area measurements were obtained in the superior vena cava, pulmonary trunk, and thoracic aorta with single-shot echo-planar MR imaging (EPI) with velocity-encoded gradients, which provided 256 images in 5 seconds, yielding 26 velocity-encoded images per second. In the superior vena cava, Valsalva's maneuver induced an 11% decrease in average flow volume, a 102% increase in peak flow velocity, a 156% increase in the time velocity integral, and a 37% decrease in cross-sectional area. MR velocity measurements agreed with echocardiographic data and supplied additional information on flow and morphology. EPI showed a reduction in venous return during Valsalva's maneuver by simultaneously assessing flow, velocity, and vessel morphology; this technique appears to be useful in the analysis of flow dynamics of the great vessels.
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Aorta Torácica/fisiología , Velocidad del Flujo Sanguíneo/fisiología , Imagen Eco-Planar/instrumentación , Procesamiento de Imagen Asistido por Computador , Arteria Pulmonar/fisiología , Maniobra de Valsalva/fisiología , Vena Cava Superior/fisiología , Adulto , Femenino , Análisis de Fourier , Humanos , Masculino , Valores de ReferenciaRESUMEN
PURPOSE: To compare the sensitivities of superparamagnetic iron oxide-enhanced and unenhanced magnetic resonance (MR) imaging at 1.5 T with those of percutaneous ultrasound (US), intraoperative US (IOUS), and dynamic computed tomography (CT) in the preoperative assessment of metastatic liver disease. MATERIALS AND METHODS: Eighteen patients with liver metastases who were candidates for curative surgery underwent presurgical imaging. Thirteen patients underwent surgery and IOUS after undergoing preoperative US, CT, and MR imaging. RESULTS: In the preoperative imaging group, the standard of reference was the total number of lesions detected with any of the modalities. Superparamagnetic iron oxide-enhanced MR imaging was the most sensitive modality (99%). In the surgical group, the standard of reference was the total number of metastases identified at IOUS and pathologic examination. IOUS had the highest sensitivity (80%), followed by superparamagnetic iron oxide-enhanced MR imaging (56%). CONCLUSION: Superparamagnetic iron oxide-enhanced high-field-strength MR imaging facilitates the preoperative evaluation of potentially curable metastatic liver disease; however, it is inferior to IOUS.
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Medios de Contraste , Hierro , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/secundario , Hígado/patología , Imagen por Resonancia Magnética/métodos , Óxidos , Neoplasias Colorrectales/patología , Dextranos , Femenino , Óxido Ferrosoférrico , Humanos , Cuidados Intraoperatorios , Ácido Yotalámico/análogos & derivados , Hígado/diagnóstico por imagen , Neoplasias Hepáticas/cirugía , Nanopartículas de Magnetita , Masculino , Persona de Mediana Edad , Cuidados Preoperatorios , Sensibilidad y Especificidad , Tomografía Computarizada por Rayos X/métodos , Ultrasonografía/métodosRESUMEN
PURPOSE: To evaluate the appearance of the heart on spin-echo (SE) and gradient-echo (GRE) echo-planar magnetic resonance (MR) images. MATERIALS AND METHODS: Nine healthy volunteers were examined with an MR imager with transaxial echo-planar imaging (EPI) capabilities. SE EPI and GRE EPI sequences were used. Full k-space signal was obtained with readout time of 40 msec per image, and total image acquisition time was 72 and 52 msec, respectively, for SE EPI and GRE EPI. RESULTS: Delineation of cardiac structures was superior with SE EPI, reflective of significantly higher contrast between myocardial and intraluminal signal intensity (SI) (P < .001). The higher (P < .01) and more homogeneous (P < .001) intraluminal SI with GRE EPI allowed better assessment of intracardiac flow. Septal SI was significantly higher for GRE EPI (P < .01), but signal homogeneity was similar for both sequences (P > .2). CONCLUSION: Diagnostic images of the heart were obtained with both SE EPI and GRE EPI. GRE EPI is more suitable for flow studies because of the higher and more homogeneous intravascular SI.
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Imagen Eco-Planar , Corazón/anatomía & histología , Adulto , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Valores de ReferenciaRESUMEN
The potential of magnetic resonance (MR) imaging for the detection of myocardial perfusion abnormalities in patients with coronary artery disease has not been fully explored. A feasibility study was conducted in 10 patients with a novel approach to determine whether myocardial ischemia can be assessed with MR imaging and dynamic first-pass bolus tracking enhanced with gadolinium tetraazacyclododecanetetraacetic acid (DOTA). Three tomographic planes were acquired before and after pharmacologic stress with dipyridamole, with use of the bolus-tracking series at rest as a reference. The change in myocardial rate of enhancement was compared with the results obtained by means of the established methods, exercise thallium scintigraphy and coronary angiography. Detection of ischemic regions with MR imaging showed a sensitivity, specificity, and diagnostic accuracy of 65%, 76%, and 74%, respectively. Ultrafast MR imaging can be used to detect regions of myocardial ischemia.
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Medios de Contraste , Dipiridamol , Compuestos Heterocíclicos , Imagen por Resonancia Magnética/métodos , Isquemia Miocárdica/diagnóstico , Miocardio/patología , Compuestos Organometálicos , Adulto , Anciano , Angiografía Coronaria , Prueba de Esfuerzo , Estudios de Factibilidad , Femenino , Gadolinio , Corazón/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Cintigrafía , Radioisótopos de TalioRESUMEN
Recent developments in measurement of intact parathormone (PTH) has enabled to generate a nomogram for parathyroid function. Blood levels of PTH can thus be interpreted in relation to calcemia. Intact PTH and calcium were assayed in blood from 99 healthy subjects studied under fasting conditions; 26 subjects were also studied during hyper- and hypocalcemia, induced by calcium and EDTA infusions, respectively. Serum levels of intact PTH which had been obtained in 99 patients were then analysed retrospectively by comparison with the nomogram. Patients whose intact PTH levels lie above the normal zone of the nomogram produce too much PTH relative to the blood calcium level (hyperparathyroidism); those falling under the normal zone produce too little (hypoparathyroidism).
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Calcio/sangre , Glándulas Paratiroides/fisiología , Hormona Paratiroidea/sangre , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Ácido Edético , Femenino , Humanos , Hipercalcemia/sangre , Hiperparatiroidismo/sangre , Hipocalcemia/sangre , Hipoparatiroidismo/sangre , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
OBJECTIVE: Pressure gradients across the aortic valve due to stenosis of the valve must be measured accurately to evaluate the functional severity of the stenosis. Velocity-encoded cine MR has been used to quantify blood flow and flow direction and, more recently, the regurgitant fraction in aortic regurgitation. The purpose of this study was to determine the feasibility and accuracy of velocity-encoded cine MR for estimating pressure gradients across the aortic valve in patients with aortic stenosis. SUBJECTS AND METHODS: We used velocity-encoded cine MR to measure flow velocity and determine pressure gradients across the aortic valve in 19 subjects. The pressure gradient (delta P) was estimated from the simplified Bernoulli equation by using the maximum instantaneous aortic jet velocity (Vmax): delta P (mm Hg) = 4V2max (m/sec). RESULTS: Maximum and mean systolic pressure gradients determined by using velocity-encoded cine MR were 3-148 mm Hg and 2-87 mm Hg, respectively, for all subjects. The pressure gradients correlated closely with gradients determined by using established methods: Doppler echocardiography and cardiac catheterization. Correlation coefficients (r) were .96 (y = 0.94x - 1.9) and .97 (y = 0.97x + 0.5), respectively. CONCLUSION: We conclude that velocity-encoded cine MR imaging provides a noninvasive and accurate means for quantifying the severity of valvular aortic stenosis. MR is a feasible method for determining pressure gradients across the aortic valve.