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Scanning Protocol (scanning + protocol)
Selected AbstractsStroke Prevention in Sickle Cell Disease (STOP) Study Guidelines for Transcranial Doppler TestingJOURNAL OF NEUROIMAGING, Issue 4 2001Fenwick T. Nichols MD ABSTRACT The Stroke Prevention in Sickle Cell Disease (STOP) trial used transcranial Doppler (TCD) to screen children with sickle cell disease with no history of stroke. Children (who consented) who had time-averaged mean of the maximum (TAMM) velocities in the middle cerebral artery and/or distal internal carotid artery were randomized to transfusion or standard. Over a slightly more than 20-month average follow-up, there were 11 strokes in the standard care arm and 1 stroke in the transfusion arm. This study has caused a great deal of interest in using TCD to screen children with sickle cell disease. For the STOP TCD data to be applied appropriately, it is necessary for users of TCD to understand how the STOP TCD examinations were performed, how the TCD velocities were measured, and which velocities were used. This article will review the STOP TCD scanning protocol and the reading protocol and review the TAMM velocity and how it differs from other velocity measurements. [source] Capillary liquid chromatography/atmospheric-pressure matrix-assisted laser desorption/ionisation ion trap mass spectrometry: a comparison with liquid chromatography/matrix-assisted laser desorption/ionisation time-of-flight and liquid chromatography/electrospray ionisation quadrupole time-of-flight for the identification of tryptic peptidesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 5 2006Colin S. Creaser The atmospheric-pressure matrix-assisted laser desorption/ionisation quadrupole ion trap (AP-MALDI-QIT) analysis of tryptic peptides is reported following capillary liquid chromatographic (LC) separation and direct analysis of a protein digest. Peptide fragments were identified by peptide mass fingerprinting from mass spectrometric data and sequence analysis obtained by tandem mass spectrometry of the principal mass spectral peaks using a data-dependent scanning protocol. These data were compared with those from mass spectrometric analysis using capillary LC/MALDI-time-of-flight (TOF) and capillary LC/electrospray ionisation (ESI)-quadrupole TOF. For all three configurations the resulting data were searched against the MSDB database, using MASCOT and the sequence coverage compared for each technique. Complementary data were obtained using the three techniques. Copyright Š 2006 John Wiley & Sons, Ltd. [source] Validation of multi-detector computed tomography as a non-invasive method for measuring ovarian volume in macaques (Macaca fascicularis)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 6 2010Jeryl C. Jones Abstract The purpose of this study was to validate low radiation dose, contrast-enhanced, multi-detector computed tomography (MDCT) as a non-invasive method for measuring ovarian volume in macaques. Computed tomography scans of four known-volume phantoms and nine mature female cynomolgus macaques were acquired using a previously described, low radiation dose scanning protocol, intravenous contrast enhancement, and a 32-slice MDCT scanner. Immediately following MDCT, ovaries were surgically removed and the ovarian weights were measured. The ovarian volumes were determined using water displacement. A veterinary radiologist who was unaware of actual volumes measured ovarian CT volumes three times, using a laptop computer, pen display tablet, hand-traced regions of interest, and free image analysis software. A statistician selected and performed all tests comparing the actual and CT data. Ovaries were successfully located in all MDCT scans. The iliac arteries and veins, uterus, fallopian tubes, cervix, ureters, urinary bladder, rectum, and colon were also consistently visualized. Large antral follicles were detected in six ovaries. Phantom mean CT volume was 0.702ąSD 0.504,cc and the mean actual volume was 0.743ąSD 0.526,cc. Ovary mean CT volume was 0.258ąSD 0.159,cc and mean water displacement volume was 0.257ąSD 0.145,cc. For phantoms, the mean coefficient of variation for CT volumes was 2.5%. For ovaries, the least squares mean coefficient of variation for CT volumes was 5.4%. The ovarian CT volume was significantly associated with actual ovarian volume (ICC coefficient 0.79, regression coefficient 0.5, P=0.0006) and the actual ovarian weight (ICC coefficient 0.62, regression coefficient 0.6, P=0.015). There was no association between the CT volume accuracy and mean ovarian CT density (degree of intravenous contrast enhancement), and there was no proportional or fixed bias in the CT volume measurements. Findings from this study indicate that MDCT is a valid non-invasive technique for measuring the ovarian volume in macaques. Am. J. Primatol. 72:530,538, 2010. Š 2010 Wiley-Liss, Inc. [source] Robust estimation of spatially variable noise fieldsMAGNETIC RESONANCE IN MEDICINE, Issue 2 2009Bennett A. Landman Abstract Consideration of spatially variable noise fields is becoming increasingly necessary in MRI given recent innovations in artifact identification and statistically driven image processing. Fast imaging methods enable study of difficult anatomical targets and improve image quality but also increase the spatial variability in the noise field. Traditional analysis techniques have either assumed that the noise is constant across the field of view (or region of interest) or have relied on separate MRI acquisitions to measure the noise field. These methods are either inappropriate for many modern scanning protocols or are overly time-consuming for already lengthy scanning sessions. We propose a new, general framework for estimating spatially variable noise fields from related, but independent MR scans that we call noise field equivalent scans. These heuristic analyses enable robust noise field estimation in the presence of artifacts. Generalization of noise estimators based on uniform regions, difference images, and maximum likelihood are presented and compared with the estimators derived from the proposed framework. Simulations of diffusion tensor imaging and T2 -relaxometry demonstrate a 10-fold reduction in mean squared error in noise field estimation, and these improvements are shown to be robust to artifact contamination. In vivo studies show that spatially variable noise fields can be readily estimated with typical data acquired at 1.5T. Magn Reson Med, 2009. Š 2009 Wiley-Liss, Inc. [source] Emergency Thoracic Ultrasound in the Differentiation of the Etiology of Shortness of Breath (ETUDES): Sonographic B-lines and N-terminal Pro-brain-type Natriuretic Peptide in Diagnosing Congestive Heart FailureACADEMIC EMERGENCY MEDICINE, Issue 3 2009Andrew S. Liteplo MD Abstract Objectives:, Sonographic thoracic B-lines and N-terminal pro-brain-type natriuretic peptide (NT-ProBNP) have been shown to help differentiate between congestive heart failure (CHF) and chronic obstructive pulmonary disease (COPD). The authors hypothesized that ultrasound (US) could be used to predict CHF and that it would provide additional predictive information when combined with NT-ProBNP. They also sought to determine optimal two- and eight-zone scanning protocols when different thresholds for a positive scan were used. Methods:, This was a prospective, observational study of a convenience sample of adult patients presenting to the emergency department (ED) with shortness of breath. Each patient had an eight-zone thoracic US performed by one of five sonographers, and serum NT-ProBNP levels were measured. Chart review by two physicians blinded to the US results served as the criterion standard. The operating characteristics of two- and eight-zone thoracic US alone, compared to, and combined with NT-ProBNP test results for predicting CHF were calculated using both dichotomous and interval likelihood ratios (LRs). Results:, One-hundred patients were enrolled. Six were excluded because of incomplete data. Results of 94 patients were analyzed. A positive eight-zone US, defined as at least two positive zones on each side, had a positive likelihood ratio (LR+) of 3.88 (99% confidence interval [CI] = 1.55 to 9.73) and a negative likelihood ratio (LR,) of 0.5 (95% CI = 0.30 to 0.82), while the NT-ProBNP demonstrated a LR+ of 2.3 (95% CI = 1.41 to 3.76) and LR, of 0.24 (95% CI = 0.09 to 0.66). Using interval LRs for the eight-zone US test alone, the LR for a totally positive test (all eight zones positive) was infinite and for a totally negative test (no zones positive) was 0.22 (95% CI = 0.06 to 0.80). For two-zone US, interval LRs were 4.73 (95% CI = 2.10 to 10.63) when inferior lateral zones were positive bilaterally and 0.3 (95% CI = 0.13 to 0.71) when these were negative. These changed to 8.04 (95% CI = 1.76 to 37.33) and 0.11 (95% CI = 0.02 to 0.69), respectively, when congruent with NT-ProBNP. Conclusions:, Bedside thoracic US for B-lines can be a useful test for diagnosing CHF. Predictive accuracy is greatly improved when studies are totally positive or totally negative. A two-zone protocol performs similarly to an eight-zone protocol. Thoracic US can be used alone or can provide additional predictive power to NT-ProBNP in the immediate evaluation of dyspneic patients presenting to the ED. [source] New perspectives of optical coherrence tomography in diagnosis and follow-up of macular holesACTA OPHTHALMOLOGICA, Issue 2009SA KABANAROU Purpose To compare Time Domain (TD) with Spectral Domain (SD) OCT for imaging macular holes, identify retinal pathology and correlate anatomical morphology after surgical intervention for hole closure with visual outcome. Methods 34 eyes of 34 patients with idiopathic macular holes stage II- IV were included in this study. Comparative studies were performed with both SD OCT (Heidelberg, Germany) and TD OCT (Stratus) using standard scanning protocols of 6 radial 6-mm scans through the fovea. All patients underwent a standard three port- pars plana vitrectomy. Postoperatively, all patients were evaluated using both OCTs. ETDRS visual acuities were recorded pre- and post-operatively. Results In general TD and SD OCTs showed comparable images of macular holes. However, the boundary line between the inner and outer segments of the photoreceptors was better imaged with the SD OCT preoperatively and postoperatively. Poor visual acuity postoperatively was measured mainly in cases with morphological disruption in this boundary line despite hole closure. Conclusion SD OCT imaging enhances the visualization of retinal anatomy in macular holes relative to TD OCT. [source] | ||||||||||