Written informed consent was obtained before all studies. Fifty-five patients (31 women, 24 men; age range, 24-71 years) were prospectively imaged at 1.5 T with quantitative MR imaging and single-voxel
MR spectroscopy, each within a single breath hold. The effects of T2* correction, spectral modeling of fat, and magnitude fitting for eddy current correction on fat quantification with MR imaging were investigated by reconstructing fat fraction images from the same source data with different combinations of error correction. Single-voxel T2-corrected MR spectroscopy was used to measure fat fraction ACY-1215 mouse and served as the reference standard. All MR spectroscopy data were postprocessed at a separate institution by an MR physicist who was
blinded to MR imaging results. Fat fractions measured with MR imaging and MR spectroscopy were compared statistically to determine the correlation (r(2)), and the slope and intercept as measures of agreement between MR imaging selleck inhibitor and MR spectroscopy fat fraction measurements, to determine whether MR imaging can help quantify fat, and examine the importance of T2* correction, spectral modeling of fat, and eddy current correction. Two-sided t tests (significance level, P =.05) were used to determine whether estimated slopes and intercepts were significantly different from 1.0 and 0.0, respectively. Sensitivity and specificity for the classification of clinically significant steatosis were evaluated.
Results: Overall, there was excellent correlation between MR imaging and MR spectroscopy for all reconstruction combinations. However, agreement was only achieved when T2* correction, spectral modeling of fat, and magnitude fitting for eddy current correction were used (r(2) = 0.99; slope +/- standard deviation = 1.00 +/- 0.01, P = .77; intercept +/- standard deviation = 0.2% +/- 0.1, P = .19).
Conclusion: T1-independent chemical shift-based water-fat separation MR imaging
methods can accurately quantify fat over the entire liver, by using MR spectroscopy as the reference standard, when T2* correction, spectral modeling of fat, and eddy current correction methods click here are used. (C)RSNA, 2011″
“Introduction and objectives: The clinical impact of patient-prosthesis mismatch on the outcome in octogenarians who undergo surgery for aortic valve replacement due to severe stenosis is unknown. Our objective was to quantify the frequency of some degree of patient-prosthesis mismatch and its impact on mortality and life quality.
Methods: We analyzed all the octogenarian patients who underwent surgery for aortic valve replacement due to severe stenosis in our center from February 2004 to April 2009. Patient-prosthesis mismatch was considered to exist when the indexed effective orifice area was <= 0.85 cm(2)/m(2).