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1.
Eur Radiol ; 33(6): 4270-4279, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36625882

RESUMEN

OBJECTIVES: To develop and test a Retina U-Net algorithm for the detection of primary lung tumors and associated metastases of all stages on FDG-PET/CT. METHODS: A data set consisting of 364 FDG-PET/CTs of patients with histologically confirmed lung cancer was used for algorithm development and internal testing. The data set comprised tumors of all stages. All lung tumors (T), lymphatic metastases (N), and distant metastases (M) were manually segmented as 3D volumes using whole-body PET/CT series. The data set was split into a training (n = 216), validation (n = 74), and internal test data set (n = 74). Detection performance for all lesion types at multiple classifier thresholds was evaluated and false-positive-findings-per-case (FP/c) calculated. Next, detected lesions were assigned to categories T, N, or M using an automated anatomical region segmentation. Furthermore, reasons for FPs were visually assessed and analyzed. Finally, performance was tested on 20 PET/CTs from another institution. RESULTS: Sensitivity for T lesions was 86.2% (95% CI: 77.2-92.7) at a FP/c of 2.0 on the internal test set. The anatomical correlate to most FPs was the physiological activity of bone marrow (16.8%). TNM categorization based on the anatomical region approach was correct in 94.3% of lesions. Performance on the external test set confirmed the good performance of the algorithm (overall detection rate = 88.8% (95% CI: 82.5-93.5%) and FP/c = 2.7). CONCLUSIONS: Retina U-Nets are a valuable tool for tumor detection tasks on PET/CT and can form the backbone of reading assistance tools in this field. FPs have anatomical correlates that can lead the way to further algorithm improvements. The code is publicly available. KEY POINTS: • Detection of malignant lesions in PET/CT with Retina U-Net is feasible. • All false-positive findings had anatomical correlates, physiological bone marrow activity being the most prevalent. • Retina U-Nets can build the backbone for tools assisting imaging professionals in lung tumor staging.


Asunto(s)
Neoplasias Pulmonares , Tomografía Computarizada por Tomografía de Emisión de Positrones , Humanos , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Fluorodesoxiglucosa F18 , Tomografía de Emisión de Positrones , Neoplasias Pulmonares/diagnóstico por imagen , Radiofármacos , Sensibilidad y Especificidad
2.
J Cardiovasc Magn Reson ; 20(1): 57, 2018 08 16.
Artículo en Inglés | MEDLINE | ID: mdl-30111368

RESUMEN

These "Guidelines for training in Cardiovascular Magnetic Resonance" were developed by the Certification Committee of the Society for Cardiovascular Magnetic Resonance (SCMR) and approved by the SCMR Board of Trustees.


Asunto(s)
Cardiología/educación , Certificación/métodos , Educación de Postgrado en Medicina/métodos , Internado y Residencia , Imagen por Resonancia Magnética , Cardiología/normas , Certificación/normas , Competencia Clínica , Curriculum , Educación de Postgrado en Medicina/normas , Humanos , Internado y Residencia/normas
3.
Magn Reson Med ; 74(2): 365-71, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25113911

RESUMEN

PURPOSE: To develop a novel sequence for simultaneous quantification of T1 and T2 relaxation times in the myocardium based on the transient phase of the balanced steady-state free precession. METHODS: A new prototype sequence, named "cardiac balanced-SSFP inversion recovery with interleaved sampling acquisition" (CABIRIA) was developed based on a single-shot bSSFP readout following an inversion pulse. With this method, T1 and T2 values can be calculated from the analysis of signal evolution. The scan duration for a single slice in vivo was 8 heartbeats, thus feasible in a breath-hold. The sequence was validated both in vitro by comparing it to conventional inversion recovery and multi-echo spin-echo methods and in 5 healthy volunteers by comparing it to the Modified Look-Locker Inversion Recovery (MOLLI) sequence and to a T2 quantification sequence based on multi-T2 -prepared bSSFP. RESULTS: The method showed good agreement with conventional methods for both T1 and T2 measurements (concordance correlation coefficient ≥ 0.99) in vitro. In healthy volunteers the measured T1 values were 1227 ± 68 ms and T2 values 37.9 ± 2.4 ms, with similar inter- and intrasubject variability with respect to existing methods. CONCLUSION: The proposed CABIRIA method enables simultaneous quantification of myocardial T1 and T2 values with good accuracy and precision.


Asunto(s)
Artefactos , Ventrículos Cardíacos/anatomía & histología , Aumento de la Imagen/métodos , Imagen por Resonancia Magnética/métodos , Imagen Multimodal/métodos , Procesamiento de Señales Asistido por Computador , Algoritmos , Femenino , Humanos , Interpretación de Imagen Asistida por Computador/métodos , Masculino , Valores de Referencia , Reproducibilidad de los Resultados , Mecánica Respiratoria , Sensibilidad y Especificidad
4.
Respiration ; 87(3): 254-64, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24458197

RESUMEN

The discussion about setting up a program for lung cancer screening was launched with the publication of the results of the National Lung Screening Trial, which suggested reduced mortality in high-risk subjects undergoing CT screening. However, important questions about the benefit-harm balance and the details of a screening program and its cost-effectiveness remain unanswered. A panel of specialists in chest radiology, respiratory medicine, epidemiology, and thoracic surgery representing all Swiss university hospitals prepared this joint statement following several meetings. The panel argues that premature and uncontrolled introduction of a lung cancer screening program may cause substantial harm that may remain undetected without rigorous quality control. This position paper focuses on the requirements of running such a program with the objective of harmonizing efforts across the involved specialties and institutions and defining quality standards. The underlying statement includes information on current evidence for a reduction in mortality with lung cancer screening and the potential epidemiologic implications of such a program in Switzerland. Furthermore, requirements for lung cancer screening centers are defined, and recommendations for both the CT technique and the algorithm for lung nodule assessment are provided. In addition, related issues such as patient management, registry, and funding are addressed. Based on the current state of the knowledge, the panel concludes that lung cancer screening in Switzerland should be undertaken exclusively within a national observational study in order to provide answers to several critical questions before considering broad population-based screening for lung cancer.


Asunto(s)
Detección Precoz del Cáncer/normas , Neoplasias Pulmonares/diagnóstico por imagen , Hospitales Universitarios , Humanos , Tamizaje Masivo , Guías de Práctica Clínica como Asunto , Medición de Riesgo , Suiza , Tomografía Computarizada por Rayos X
5.
Acta Radiol ; 54(7): 778-84, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23761544

RESUMEN

BACKGROUND: The principal concern of any radiation exposure in computed tomography (CT) is the induction of stochastic risks of developing a radiation-induced cancer. The results given in this manuscript will allow to (re-)calculate yield of chest CT. PURPOSE: To demonstrate a method to evaluate the lifetime attributable risk (LAR) of cancer incidence/mortality due to a single diagnostic investigation in a 1-year cohort of consecutive chest CT for suspected pulmonary embolism (PE). MATERIAL AND METHODS: A 1-year cohort of consecutive chest CT for suspected PE using a standard scan protocol was analyzed retrospectively (691 patients, 352 men, 339 women). Normalized patient-specific estimations of the radiation doses received by individual organs were correlated with age- and sex-specific mean predicted cancer incidence and age- and sex-specific predicted cancer mortality based on the BEIR VII results. Additional correlation was provided for natural occurring risks. RESULTS: LAR of cancer incidence/mortality following one chest CT was calculated for cancer of the stomach, colon, liver, lung, breast, uterus, ovaries, bladder, thyroid, and for leukemia. LAR remains very low for all age and sex categories, being highest for cancer of the lungs and breasts in 20-year-old women (0.61% and 0.4%, respectively). Summation of all cancer sites analyzed raised the cumulative relative LAR up to 2.76% in 20-year-old women. CONCLUSION: Using the method presented in this work, LAR of cancer incidence and cancer mortality for a single chest CT for PE seems very low for all age groups and both sexes, but being highest for young patients. Hence the risk for radiation-induced organ cancers must be outweighed with the potential benefit or a treatment and the potential risks of a missed and therefore untreated PE.


Asunto(s)
Neoplasias Inducidas por Radiación/epidemiología , Embolia Pulmonar/diagnóstico por imagen , Tomografía Computarizada por Rayos X/efectos adversos , Anciano , Femenino , Humanos , Incidencia , Masculino , Neoplasias Inducidas por Radiación/mortalidad , Dosis de Radiación , Estudios Retrospectivos , Medición de Riesgo , Factores de Riesgo
6.
Infection ; 40(6): 677-84, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22802096

RESUMEN

BACKGROUND: The clinical characteristics of human metapneumovirus (hMPV)-associated lower respiratory tract infection (LRTI) after allogeneic hematopoietic stem cell transplantation (HSCT) is not well described. We describe the clinical course in eight HSCT recipients suffering from hMPV infection. METHODS: We prospectively included all patients with hMPV-associated LRTI after allogeneic HSCT during a period of 1 year. hMPV was diagnosed by multiplex polymerase chain reaction (PCR) from bronchoalveolar lavage (BAL). RESULTS: Eight patients with hMPV-associated LRTI were identified from 93 BAL samples. Three of the eight patients had co-infections with other pathogens. The median age of the patients was 45 years [interquartile range (IQR) 36.8-53.5], the median time posttransplant was 473 days (IQR 251-1,165), 5/8 patients had chronic graft-versus-host disease (cGvHD), and 6/8 patients received immunosuppression. Chest computed tomography (CT) scanning showed a ground-glass pattern in 7/8 patients. Seven of eight patients required hospitalization due to severe symptoms and hypoxemia. All were treated with intravenous immunoglobulin (IVIG), which was combined with oral ribavirin in six patients. The mortality rate was 12.5 % (1/8). CONCLUSIONS: hMPV-associated LRTI in allogeneic HSCT recipients are not uncommon and present with unspecific respiratory symptoms, ground-glass pattern in CT scanning, and co-infection.


Asunto(s)
Trasplante de Células Madre Hematopoyéticas/efectos adversos , Metapneumovirus/aislamiento & purificación , Infecciones por Paramyxoviridae/etiología , Infecciones del Sistema Respiratorio/etiología , Adulto , Antivirales/uso terapéutico , Quimioterapia Combinada , Femenino , Humanos , Huésped Inmunocomprometido , Inmunoglobulinas Intravenosas/uso terapéutico , Masculino , Persona de Mediana Edad , Infecciones por Paramyxoviridae/diagnóstico , Infecciones por Paramyxoviridae/tratamiento farmacológico , Infecciones del Sistema Respiratorio/diagnóstico , Infecciones del Sistema Respiratorio/tratamiento farmacológico , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Ribavirina/uso terapéutico , Tomografía Computarizada por Rayos X , Trasplante Homólogo
7.
Magn Reson Med ; 66(6): 1666-73, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21523822

RESUMEN

A novel technique to guide a subjects' breathing pattern using a respiratory biofeedback (rBF) "game" to improve respiratory efficiency is presented. The continuously adaptive windowing strategy, a fully automatic and highly efficient free-breathing navigator gated technique, is used to acquire the data as it ensures that all potential navigator acceptance windows are possible. This enables the rBF to be fully adaptable to a subject's respiratory pattern. Images of the thoracic aorta acquired using balanced steady-state free precession with continuously adaptive windowing strategy respiratory motion control, with and without rBF, were compared in 10 healthy subjects. Total scan time was reduced by using rBF. The mean scan time was reduced from 7 min 44 s (463 cardiac cycles, ± 127 cc) without rBF to 5 min 43 s (380 cardiac cycles, ± 118 cc) with the use of rBF (P < 0.05). Respiratory efficiency was increased from 45% without rBF to 56% with rBF (P < 0.01). Image quality was the same for both techniques (P = ns). In conclusion, rBF significantly improved respiratory efficiency and reduced acquisition duration without affecting image quality.


Asunto(s)
Aorta Torácica/anatomía & histología , Artefactos , Aumento de la Imagen/métodos , Interpretación de Imagen Asistida por Computador/métodos , Angiografía por Resonancia Magnética/métodos , Mecánica Respiratoria , Técnicas de Imagen Sincronizada Respiratorias/métodos , Adulto , Algoritmos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
8.
Eur Radiol ; 18(12): 2879-84, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18654785

RESUMEN

Isolation of the pulmonary veins has emerged as a new therapy for atrial fibrillation. Pre-procedural magnetic resonance (MR) imaging enhances safety and efficacy; moreover, it reduces radiation exposure of the patients and interventional team. The purpose of this study was to optimize the MR protocol with respect to image quality and acquisition time. In 31 patients (23-73 years), the anatomy of the pulmonary veins, left atrium and oesophagus was assessed on a 1.5-Tesla scanner with four different sequences: (1) ungated two-dimensional true fast imaging with steady precession (2D-TrueFISP), (2) ECG/breath-gated 3D-TrueFISP, (3) ungated breath-held contrast-enhanced three-dimensional turbo fast low-angle shot (CE-3D-tFLASH), and (4) ECG/breath-gated CE-3D-TrueFISP. Image quality was scored from 1 (structure not visible) to 5 (excellent visibility), and the acquisition time was monitored. The pulmonary veins and left atrium were best visualized with CE-3D-tFLASH (scores 4.50 +/- 0.52 and 4.59 +/- 0.43) and ECG/breath-gated CE-3D-TrueFISP (4.47 +/- 0.49 and 4.63 +/- 0.39). Conspicuity of the oesophagus was optimal with CE-3D-TrueFISP and 2D-TrueFISP (4.59 +/- 0.35 and 4.19 +/- 0.46) but poor with CE-3D-tFLASH (1.03 +/- 0.13) (p < 0.05). Acquisition times were shorter for 2D-TrueFISP (44 +/- 1 s) and CE-3D-tFLASH (345 +/- 113 s) compared with ECG/breath-gated 3D-TrueFISP (634 +/- 197 s) and ECG/breath-gated CE-3D-TrueFISP (636 +/- 230 s) (p < 0.05). In conclusion, an MR imaging protocol comprising CE-3D-tFLASH and 2D-TrueFISP allows assessment of the pulmonary veins, left atrium and oesophagus in less than 7 min and can be recommended for pre-procedural imaging before electric isolation of pulmonary veins.


Asunto(s)
Técnicas de Imagen Sincronizada Cardíacas/métodos , Ablación por Catéter/métodos , Aumento de la Imagen/métodos , Imagen por Resonancia Magnética/métodos , Venas Pulmonares/patología , Venas Pulmonares/cirugía , Mecánica Respiratoria , Cirugía Asistida por Computador/métodos , Adulto , Anciano , Artefactos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Control de Calidad , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Resultado del Tratamiento , Adulto Joven
9.
Circulation ; 103(6): 871-6, 2001 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-11171797

RESUMEN

BACKGROUND: Because ischemically injured myocardium is frequently composed of viable and nonviable portions, a method to discriminate the two is useful for clinical management. METHODS AND RESULTS: Ischemically injured myocardium was characterized with extracellular nonspecific (Gd-DTPA) and necrosis-specific (mesoporphyrin) MR contrast media in rats. Relaxation rates (R1) were measured on day 1 and day 2 by inversion-recovery echoplanar imaging. Spin-echo imaging was used to define contrast-enhanced regions and regional wall thickening. Gadolinium concentration, area at risk, and infarct size were measured at postmortem examination. DeltaR1 ratio (DeltaR1(myocardium)/DeltaR1(blood)) after administration of Gd-DTPA was greater in ischemically injured myocardium (1.20+/-0.15) than in normal myocardium (0.47+/-0.05, P<0.05), which was attributed to differences in gadolinium concentration and water content. The Gd-DTPA-enhanced region on day 2 was larger (32.8+/-0.9%) than true infarction as demonstrated by triphenyltetrazolium chloride (TTC) (24.6+/-1.4%, P<0.001, r=0.21). Bland-Altman analysis revealed that the Gd-DTPA-enhanced region overestimated true infarct size by 7.8+/-5.9%. On the other hand, the mesoporphyrin-enhanced region (26.9+/-1.8%, P=NS, r=0.87) and true infarct size were identical. The difference in the areas demarcated by the 2 agents is the peri-infarction. Systolic and diastolic MR images revealed no wall thickening in the mesoporphyrin-enhanced region (0.3+/-3.3%) but reduced thickening in the Gd-DTPA-enhanced rim (8.5+/-5.5%, P<0.05). CONCLUSIONS: The Gd-DTPA-enhanced region encompasses both viable and nonviable portions of the ischemically injured myocardium. The Gd-DTPA-enhanced area overestimated infarct size, but the mesoporphyrin-enhanced area matched true infarct size. The salvageable peri-infarction zone can be characterized with double-contrast-enhanced and functional MR imaging; the mismatched area of enhancement between the 2 agents shows residual wall thickening.


Asunto(s)
Medios de Contraste , Imagen por Resonancia Magnética/métodos , Isquemia Miocárdica/diagnóstico , Daño por Reperfusión Miocárdica/diagnóstico , Miocardio/patología , Animales , Gadolinio DTPA , Mesoporfirinas , Metaloporfirinas , Isquemia Miocárdica/patología , Ratas , Ratas Sprague-Dawley , Factores de Tiempo
10.
J Am Coll Cardiol ; 32(1): 97-102, 1998 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9669255

RESUMEN

OBJECTIVES: We sought to test the hypothesis that late recanalization of infarct-related coronary arteries (IRAs) improves long-term left ventricular (LV) function. BACKGROUND: Reperfusion within 24 h of an acute myocardial infarction (MI) has been shown to improve myocardial healing and to reduce infarct expansion. Uncontrolled data suggest that there may be a time window of several weeks for such an effect. METHODS: Sixteen asymptomatic patients 10 +/- 4 days after a first Q wave anterior wall MI with persistent left anterior descending coronary artery occlusion and infarct-zone akinesia were randomized to immediate (2 weeks) or delayed (3 months) angioplasty. Repeat catheterization and cardiac magnetic resonance imaging (MRI) were performed after 3 and 12 months. RESULTS: Angiography 3 months after MI revealed that LV ejection fraction (LVEF) had increased ([mean +/- SD] 54.4 +/- 4.3% vs. 63.9 +/- 7.4%, p < 0.01) as a result of improved regional function (p < 0.01) and LV end-systolic volume had decreased (p < 0.002), whereas LV end-diastolic volume remained unchanged. With delayed angioplasty, LVEF, infarct zone wall motion and LV volumes did not improve. Cardiac MRI at baseline and at 3 and 12 months confirmed these findings and extended them up to 1 year, indicating that delayed angioplasty could no longer improve LV function because of marked LV dilation (p < 0.01). Immediate angioplasty had a high success rate, but restenosis (50%) was accompanied by new severe angina as a clinical indicator of salvaged myocardium, which did not occur after delayed angioplasty. CONCLUSIONS: This pilot study in selected patients supports the hypothesis that myocardial viability persists ("hibernation") for 2 to 3 weeks but not for 3 months after MI, during which time it may be worthwhile to restore blood flow to a large myocardial territory, even in asymptomatic patients, to improve long-term LV function.


Asunto(s)
Infarto del Miocardio/terapia , Daño por Reperfusión Miocárdica/diagnóstico , Aturdimiento Miocárdico/diagnóstico , Función Ventricular Izquierda/fisiología , Adulto , Anciano , Cateterismo Cardíaco , Circulación Coronaria/fisiología , Femenino , Estudios de Seguimiento , Hemodinámica/fisiología , Humanos , Angiografía por Resonancia Magnética , Masculino , Persona de Mediana Edad , Infarto del Miocardio/fisiopatología , Daño por Reperfusión Miocárdica/fisiopatología , Aturdimiento Miocárdico/fisiopatología , Proyectos Piloto , Factores de Tiempo
11.
J Am Coll Cardiol ; 32(3): 787-93, 1998 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9741528

RESUMEN

OBJECTIVES: The purpose of this study was to measure the accumulation of labeled albumin and to visualize its distribution pattern in reperfused infarcted myocardium as a function of time between onset of reperfusion and administration of the tracer. BACKGROUND: Myocardial microvascular injury leads to leakage of albumin from the intravascular space. Quantitative measurements of GdDTPA-albumin with inversion recovery echoplanar imaging (IR-EPI) may allow noninvasive monitoring of microvascular injury. METHODS: After 1 h of coronary artery occlusion, 56 rats were injected with GdDTPA-albumin or 123I-GdDTPA-albumin either immediately before reperfusion or 1/2, 1 or 24 h after reperfusion. GdDTPA-albumin in blood, normal myocardium and reperfused infarction was dynamically measured with IR-EPI during 1 h postinjection (PI). Autoradiograms were obtained at 15 min PI. Accumulation of labeled albumin in myocardium was expressed as the ratio of myocardial to blood content. RESULTS: In normal myocardium, the ratio of changes of relaxation rate-ratio (deltaR1-ratio) was 0.12+/-0.01 and did not change over 1 h. In reperfused infarction, however, the deltaR1-ratio increased after administration. Animals given GdDTPA-albumin before reperfusion exhibited fastest accumulation (deltaR1-ratio 15 min PI: 0.56+/-0.03) and essentially homogeneous distribution. The accumulation was slower when administered at 1/2, 1 and 24 h after reperfusion (deltaR1-ratios 15 min PI: 0.39+/-0.03; 0.31+/-0.04; 0.16+/-0.01; p < 0.001 compared to administration before reperfusion). Moreover, the tracer accumulated predominantly in the periphery of the injury zone. CONCLUSIONS: Amount and distribution pattern of labeled albumin in reperfused infarction are modulated by duration of reperfusion. The accumulation of GdDTPA-albumin can be quantified by IR-EPI. Thus, IR-EPI may be useful to noninvasively monitor myocardial microvascular injury in reperfused infarction.


Asunto(s)
Imagen Eco-Planar , Infarto del Miocardio/diagnóstico , Daño por Reperfusión Miocárdica/diagnóstico , Albúminas , Animales , Volumen Sanguíneo/fisiología , Medios de Contraste , Vasos Coronarios/patología , Femenino , Gadolinio DTPA , Humanos , Microcirculación/patología , Miocardio/patología , Ratas , Ratas Sprague-Dawley
12.
Mol Imaging Biol ; 17(5): 595-608, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26286794

RESUMEN

This paper summarises key themes and discussions from the 4th international workshop dedicated to the advancement of the technical, scientific and clinical applications of combined positron emission tomography (PET)/magnetic resonance imaging (MRI) systems that was held in Tübingen, Germany, from February 23 to 27, 2015. Specifically, we summarise the three days of invited presentations from active researchers in this and associated fields augmented by round table discussions and dialogue boards with specific topics. These include the use of PET/MRI in cardiovascular disease, paediatrics, oncology, neurology and multi-parametric imaging, the latter of which was suggested as a key promoting factor for the wider adoption of integrated PET/MRI. Discussions throughout the workshop and a poll taken on the final day demonstrated that attendees felt more strongly that PET/MRI has further advanced in both technical versatility and acceptance by clinical and research-driven users from the status quo of last year. Still, with only minimal evidence of progress made in exploiting the true complementary nature of the PET and MRI-based information, PET/MRI is still yet to achieve its potential. In that regard, the conclusion of last year's meeting "the real work has just started" still holds true.


Asunto(s)
Imagen por Resonancia Magnética , Imagen Multimodal , Tomografía de Emisión de Positrones , Alemania , Humanos
13.
Eur J Pharmacol ; 208(1): 17-23, 1991 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-1657618

RESUMEN

High-affinity agonist binding to formyl peptide receptors in membranes of myeloid differentiated human leukemia (HL 60) cells is known to be regulated by guanine nucleotides, most potently by the GTP analog, guanosine-5'-O-(3-thiotriphosphate) (GTP[S]). Here we analyzed whether nucleoside diphosphokinase present in these membranes and capable of forming GTP[S] from GDP and adenosine-5'-O-(3-thiotriphosphate) (ATP[S]) can contribute to nucleotide regulation of agonist receptor binding. Using GDP and ATP[S] at concentrations causing by themselves only small reductions in receptor binding of the labelled formyl peptide, N-formyl-methionyl-leucyl-phenylalanine ([3H]FMLP), a marked potentiation (up to 30-fold) was observed when both nucleotides were combined. Under conditions in which the combination of GDP and ATP[S] induced 70-90% of maximal inhibition of [3H]FMLP binding, a total concentration of about 7 nM GTP[S] formed was measured. The synergistic effect of GDP and ATP[S] on [3H]FMLP binding was not seen in the presence of UDP (1 mM), which blocked formation of GTP[S] from GDP and ATP[S]. Furthermore, no potentiation was observed when instead of GDP and ATP[S], guanosine-5'-O-(2-thiodiphosphate) and adenylyl-5'-imidodiphosphate, respectively, were used. Finally, regulation of [3H]FMLP binding by ATP[S] plus GDP (or GTP) was a time-dependent process, reaching maximal inhibition after 20-30 min of incubation at 25 degrees C. The data indicate that nucleoside diphosphokinase present in membranes of HL 60 cells can transfer the thiophosphate group of ATP[S] to GDP leading to formation of GTP[S] and that the GTP[S] thus formed efficiently binds to G proteins interacting with formyl peptide receptors and thereby regulates their agonist binding affinity.


Asunto(s)
Adenosina Trifosfato/análogos & derivados , Guanosina 5'-O-(3-Tiotrifosfato)/metabolismo , N-Formilmetionina Leucil-Fenilalanina/metabolismo , Nucleósido-Difosfato Quinasa/metabolismo , Receptores Inmunológicos/metabolismo , Adenosina Trifosfato/metabolismo , Adenosina Trifosfato/farmacología , Sitios de Unión , Proteínas de Unión al GTP/metabolismo , Guanosina 5'-O-(3-Tiotrifosfato)/farmacología , Guanosina Difosfato/metabolismo , Guanosina Difosfato/farmacología , Humanos , Leucemia Mieloide , Receptores de Formil Péptido , Células Tumorales Cultivadas , Uridina Difosfato/metabolismo , Uridina Difosfato/farmacología
14.
Cardiol Clin ; 16(2): 277-94, 1998 May.
Artículo en Inglés | MEDLINE | ID: mdl-9627761

RESUMEN

With development of cine and velocity encoded magnetic resonance imaging, it is now feasible to detect and quantify aortic and mitral stenosis and regurgitation accurately. In addition, magnetic resonance imaging has the capabilities to assess simultaneously left and right ventricular mass, volumes, and function precisely. The high accuracy and reproducibility of magnetic resonance imaging in quantification of regurgitation and ventricular function has the potential to provide improved monitoring of therapy and optimal timing of surgery in patients with valvular dysfunction. In comparison to echocardiography and angiography, some current limitations of magnetic resonance imaging to an integrated approach of valvular heart disease exist, which may be removed with future refinement of magnetic resonance imaging technology for cardiovascular imaging.


Asunto(s)
Enfermedades de las Válvulas Cardíacas/diagnóstico , Válvulas Cardíacas/patología , Imagen por Resonancia Magnética , Humanos
15.
Rofo ; 170(4): 397-403, 1999 Apr.
Artículo en Alemán | MEDLINE | ID: mdl-10341801

RESUMEN

An increasing number of patients with complex congenital heart disease reaches adulthood, because treatment and patient outcome have improved considerably in recent years. Monitoring of these patients requires both definition of cardiac anatomy and assessment of function with good reproducibility. Complications after surgical repair such as restenoses of pulmonary arteries after surgical repair of tetralogy of Fallot, ventricular hypertrophy, stenoses or leakage of baffles, or stenosis and aneurysms of anastomoses have to be detected at an early stage. Magnetic resonance imaging (MRI) is an excellent tool to monitor these patients because of its noninvasive nature, its good interstudy and interobserver reproducibility, and because it allows assessment of both cardiac anatomy and function. This paper reviews the current applications of MRI in complex congenital heart disease in adults.


Asunto(s)
Cardiopatías Congénitas/diagnóstico , Imagen por Resonancia Magnética , Adulto , Corazón/anatomía & histología , Humanos , Imagen por Resonancia Magnética/métodos , Miocardio/patología , Periodo Posoperatorio
16.
Rofo ; 173(3): 224-8, 2001 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-11293864

RESUMEN

PURPOSE: To compare the indications for biopsy with and without the use of the Breast Imaging Reporting and Data System. MATERIAL AND METHODS: Biopsies using the ABBI were performed in 62 patients with 64 non-palpable evident mammographic lesions. The initial decision for biopsy was made by non-radiologists due to suspicious microcalcifications (n = 53) and masses (n = 11). The indication was retrospectively reassessed by adopting the BI-RADS classification by three radiologists in consensus. The positive predictive value (PPV) of both indication strategies was assessed and compared. RESULTS: Biopsies adopting ABBI were performed without major side-effects and were diagnostic. Carcinoma was present in 14 lesions: nine specimens were diagnosed as DCIS and five as invasive carcinomas. For the 50 benign lesions histology revealed mastopathies (26/50) and fibroadenomas (8/50) as the most frequent diagnosis. The positive predictive value (PPV) for the initial indication was 22%, whereas PPV for BI-RADS based indications (categories 4 and 5) was 31%. CONCLUSION: ABBI enables stereotactically-guided procedures that result in representative and diagnostic biopsies. Standardized criteria like BI-RADS improve the PPV and should be a mandatory part of mammographic evaluation. Radiologists should remain involved in the decision making.


Asunto(s)
Biopsia/instrumentación , Neoplasias de la Mama/patología , Mama/patología , Carcinoma in Situ/patología , Carcinoma Ductal de Mama/patología , Carcinoma/patología , Mamografía , Adulto , Anciano , Enfermedades de la Mama/diagnóstico , Enfermedades de la Mama/diagnóstico por imagen , Enfermedades de la Mama/patología , Neoplasias de la Mama/diagnóstico , Neoplasias de la Mama/diagnóstico por imagen , Calcinosis/diagnóstico , Calcinosis/diagnóstico por imagen , Calcinosis/patología , Carcinoma/diagnóstico , Carcinoma/diagnóstico por imagen , Carcinoma in Situ/diagnóstico , Carcinoma in Situ/diagnóstico por imagen , Carcinoma Ductal de Mama/diagnóstico , Carcinoma Ductal de Mama/diagnóstico por imagen , Diagnóstico Diferencial , Femenino , Humanos , Persona de Mediana Edad , Palpación , Papiloma/diagnóstico , Papiloma/diagnóstico por imagen , Papiloma/patología , Valor Predictivo de las Pruebas , Estudios Retrospectivos , Técnicas Estereotáxicas , Factores de Tiempo
17.
Int J Cardiovasc Imaging ; 30(2): 323-8, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24221905

RESUMEN

To test feasibility of myocardial T1 mapping of the right ventricle (RV) at systole when myocardium is more compact and to determine the most appropriate imaging plane. 20 healthy volunteers (11 men; 33 ± 8 years) were imaged on a 1.5T scanner (MAGNETOM Avanto, Siemens AG, Erlangen, Germany). A modified look-locker inversion-recovery sequence was acquired at mid-ventricular short axis (SAX), as horizontal long-axis view and as transversal view at systole (mean trigger time 363 ± 37 ms). Myocardial T1 time of the left-ventricular and RV myocardium was measured within a region of interest (ROI) on generated T1-maps. The most appropriate imaging plane for the RV was determined by the ability to draw a ROI including the largest amount of myocardium without including adjacent tissue or blood. At systole, when myocardium is thicker, measurements of the RV myocardium were feasible in 18/20 subjects. Average size of the ROI was 0.42 ± 0.28 cm(2). In 10/18 subjects, short axis was the most appropriate imaging plane to obtain measurements (p = 0.034). Average T1 time of the RV myocardium was 1,016 ± 61 ms, and average T1 of the left-ventricular (LV) was 956 ± 25 ms (p < 0.001). T1 mapping of the RV myocardium is feasible during systole in the majority of healthy subjects but with a small ROI only. SAX plane was the optimal imaging plane in the majority of subjects. Native myocardial T1 time of the RV is significantly longer compared to the LV, which might be explained by the naturally higher collagen content of the RV.


Asunto(s)
Ventrículos Cardíacos/anatomía & histología , Imagen por Resonancia Cinemagnética , Miocardio , Adulto , Colágeno/análisis , Estudios de Factibilidad , Femenino , Voluntarios Sanos , Ventrículos Cardíacos/química , Humanos , Masculino , Persona de Mediana Edad , Miocardio/química , Valor Predictivo de las Pruebas , Valores de Referencia , Sístole , Función Ventricular Derecha , Adulto Joven
20.
Praxis (Bern 1994) ; 99(1): 55-9, 2010 Jan 06.
Artículo en Alemán | MEDLINE | ID: mdl-20052640

RESUMEN

We report the case of a 83-year-old female patient with ST elevation myocardial infarction who developed a rectus sheath hematoma during treatment with antiplatelet medication and systemic anticoagulants following cough attacks. The patient presented with progressive pain in the left lower abdomen associated with a palpable mass and anaemia. Abdominal sonography and computed tomography revealed a rectus sheath hematoma. We discuss pathogenesis, clinical findings, diagnostic workup and therapy. Moreover, we review the current related literature.


Asunto(s)
Abdomen Agudo/etiología , Anticoagulantes/efectos adversos , Fibrilación Atrial/tratamiento farmacológico , Tos/complicaciones , Hematoma/inducido químicamente , Embolia Intracraneal/tratamiento farmacológico , Anciano de 80 o más Años , Anticoagulantes/uso terapéutico , Aspirina/efectos adversos , Aspirina/uso terapéutico , Clopidogrel , Seudoobstrucción Colónica/diagnóstico , Comorbilidad , Dalteparina/efectos adversos , Dalteparina/uso terapéutico , Diagnóstico Diferencial , Relación Dosis-Respuesta a Droga , Quimioterapia Combinada , Femenino , Hematoma/diagnóstico , Humanos , Fenprocumón/efectos adversos , Fenprocumón/uso terapéutico , Recto del Abdomen , Ticlopidina/efectos adversos , Ticlopidina/análogos & derivados , Ticlopidina/uso terapéutico
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