RESUMEN
PURPOSE: To determine whether imaging at 3 T could improve and prolong the tag contrast compared to images acquired at 1.5 T in normal volunteers, and whether such improvement would translate into the ability to perform strain measurements in diastole. MATERIALS AND METHODS: Normal volunteers (N = 13) were scanned at 1.5 T (GE Signa CV/i) and 3.0 T (GE VH/i). An ECG-triggered, segmented k-space, spoiled-gradient-echo grid-tagged sequence was used during cine acquisition. Tag contrast was determined by the difference of the mean signal intensity (SI) of the tagline to the mean SI of the myocardium divided by the standard deviation (SD) of the noise (CNR(tag)). Matched short-axis (SA) slices were analyzed. Strain measurements were performed on images using a 2D strain analysis software program (harmonic phase (HARP)). RESULTS: The average CNR(tag) over the cardiac cycle was superior at 3 T compared to 1.5 T for all slices (3 T: 23.4 +/- 12.1, 1.5 T: 9.8 +/- 8.4; P < 0.0001). This difference remained significant at cycle initiation, end-systole, and the end R-R interval (at cycle termination: 3 T = 14.0 +/- 11.0 vs. 1.5 T = 4.4 +/- 3.5; P < 0.01). Strain measures were obtainable only in early systole for 1.5 T images, but were robust throughout the entire R-R interval for 3 T images. CONCLUSION: Imaging at 3 T had a significant benefit for myocardial tag persistence through the cardiac cycle. The improvement allowed strain analysis to be performed into diastole.
Asunto(s)
Corazón/fisiología , Imagen por Resonancia Magnética/métodos , Adulto , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Contracción MiocárdicaRESUMEN
PURPOSE: To compare myocardial enhancement during first-pass myocardial perfusion imaging at 3.0 Tesla (T) and 1.5T. MATERIALS AND METHODS: First-pass myocardial perfusion imaging was performed on twelve normal subjects at 3T and 1.5T using an interleaved notched saturation recovery gradient echo pulse sequence. Subjects received either 0.10 mmol/kg for both scans (group 1), 0.075 mmol/kg for both scans (group 2), or 0.075 mmol/kg for the 3T scan and 0.10 mmol/kg for the 1.5T scan (group 3). RESULTS: Contrast enhancement was significantly greater at 3T than at 1.5T for the 12 subjects whether enhancement was normalized to baseline signal intensity (2.58 +/- 0.76 vs. 1.52 +/- 0.37, p < 0.0001) or to noise (57.6 +/- 19.7 vs. 14.7 +/- 7.8, p < 0001). For each of the three groups, contrast enhancement was significantly greater at 3T versus 1.5T (p < 0.0001, p < 0.001, p < 0.008 when normalized to baseline signal; p < 0.0001 for all groups when normalized to noise). CONCLUSION: 3T improves contrast in first-pass myocardial perfusion imaging at either 0.10 mmol/kg or 0.075 mmol/kg.
Asunto(s)
Medios de Contraste/administración & dosificación , Gadolinio DTPA/administración & dosificación , Aumento de la Imagen/métodos , Angiografía por Resonancia Magnética/métodos , Miocardio/patología , Adulto , Relación Dosis-Respuesta a Droga , Femenino , Imagen de Acumulación Sanguínea de Compuerta , Ventrículos Cardíacos/patología , Humanos , Procesamiento de Imagen Asistido por Computador , MasculinoRESUMEN
The spectacular increase in the prevalence of obesity in our society and the significant complications and comorbidities that it gives rise to have stimulated the interest of scientists and public in this pathology. Surgical treatment is at present the only efficient and lasting treatment for morbid obesity and in many cases it appreciably improves, and even definitively cures, associated complications such as the case of diabetes or hypertension. Amongst the different techniques of bariatric surgery, the gastric bypass (GBP) seems to be definitively establishing itself, since it offers an excellent balance between loss of weight (>70% of the excess), surgical risk and subsequent quality of life. The possibility of carrying out this technique employing a laparoscopic approach has improved its acceptance by doctors and patients while it has made it possible to reduce morbidity and mortality, length of hospital stay and costs. Proximal GBP is carried on those patients with an BMI <60 Kg/m2; for BMI >60 Kg/m2 the GBP employed is denominated distal. Between October 2003 and November 2005, our centre performed 55 laparoscopic proximal Roux-en-Y gastric bypasses via laparoscopy. These involved 42 women and 13 males with an average age of 44 years. The average BMI was 43.5 (35-55.8). The average basal weight was 116.15 Kg. There was no peroperative mortality, nor reinterventions. The BMI after 12 months was 28.4. The average basal weight was 74.2 Kg. Laparoscopic Roux-en-Y proximal gastric bypass is a safe and efficient technique for the treatment of morbid obesity.
Asunto(s)
Bariatria , Derivación Gástrica , Laparoscopía , Obesidad Mórbida/cirugía , Adulto , Anastomosis en-Y de Roux , Índice de Masa Corporal , Femenino , Derivación Gástrica/economía , Derivación Gástrica/métodos , Humanos , Tiempo de Internación , Masculino , Persona de Mediana Edad , Calidad de Vida , Resultado del Tratamiento , Pérdida de PesoRESUMEN
Prolongation of the QTc interval during stress testing predicts myocardial ischemia with a sensitivity of 88% and a specificity of 93%. Measurement of the QTc segment should be considered as an adjunctive electrocardiographic variable in the interpretation of stress tests and is even useful in patients who are not able to achieve the age-predicted target heart rate level.