Magnetic resonance imaging
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Comparative Study
Readout-segmented echo-planar imaging in the evaluation of sinonasal lesions: A comprehensive comparison of image quality in single-shot echo-planar imaging.
To investigate the role of readout-segmented echo-planar imaging using parallel imaging and a two-dimensional (2D) navigator (RESOLVE) in the evaluation of sinonasal lesions and to qualitatively and quantitatively compare the image qualities of single-shot echo-planar imaging (SS-EPI) and RESOLVE. ⋯ RESOLVE significantly improved the image quality for evaluations of sinonasal lesions by reducing the susceptibility artifacts, distortion and blurring compared with SS-EPI. RESOVLE offers more accurate ADC values of sinonasal lesions than SS-EPI.
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To evaluate the correlation between parameters of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) and microvessel density (MVD) measurements in rabbit VX2 liver tumor models after percutaneous ethanol injection (PEI) and to observe influence of PEI on angiogenesis in a rabbit VX2 liver tumor model with dynamic contrast enhanced magnetic resonance imaging (DCE-MRI). ⋯ DCE-MRI could be used to evaluate the efficiency of VX2 liver tumor after PEI. The quantitative parameter Ktrans and semi-quantitative parameter iAUC60 of DCE-MRI are correlated with MVD, which can assess tumor angiogenesis noninvasively of VX2 liver tumor model, and ethanol has no significant impact on angiogenesis of viable tumor 1week later after PEI.
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Comparative Study
Ultrashort echo (UTE) versus pointwise encoding time reduction with radial acquisition (PETRA) sequences at 3 Tesla for knee meniscus: A comparative study.
The purposes of this study were to (1) correlate the ultrashort echo time (TE) signal intensity of the pointwise encoding time reduction with radial acquisition (PETRA) sequence with that of the ultrashort echo (UTE) sequence using in vivo meniscal ultrashort TE imaging of the knee with a 3-Tesla (3T) clinical magnetic resonance imaging (MRI) scanner and (2) compare the two ultrashort TE sequences in three groups of patients with normal, degenerated, and torn knee menisci. ⋯ Both the PETRA sequence and the UTE sequence can visualize the short T2 tissue. We demonstrated that there was significantly lower signal intensity on the ultrashort TE UTE and the PETRA images of patients with meniscal tear.
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The aortic wall and intraluminal thrombus (ILT) have been increasingly studied as potential markers of progressive disease with abdominal aortic aneurysms (AAAs). Our goal was to develop a high resolution, 3D black blood MR technique for AAA wall and ILT imaging within a clinically acceptable scan time. ⋯ High resolution, 3D black blood MRI of AAAs can be achieved in a clinical accepted scan time with reduction of flow artifacts using the DANTE preparation pulse. Signal characteristics of ILT can be quantified and may be used for improved patient-specific risk stratification.
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To investigate the brain iron dependence of transverse relaxation rate difference methods derived from spin echo and gradient echo measurements from two field strengths. ⋯ The transverse relaxation difference methods FDRI and R2(') at 4.7T had high correlations to predicted iron content similar to R2 and R2(⁎) at 4.7T. Although R2(') had smaller y-intercept with estimated iron concentration than FDRI, in white matter R2(') demonstrated strongest dependence on fiber orientation with respect to B0. These results suggest that for brain iron correlation, there is minimal value of transverse difference methods over a single R2(⁎) measurement at highest available field, which was 4.7T.