The purpose of this paper is to investigate the feasibility of using a similarity coefficient map（SCM） in improving the morphological evaluation of T2＊ weighted（T2＊W） magnatic resonance imaging（MRI） for renal cancer.Simulation studies and in vivo 12-echo T2＊W experiments for renal cancers were performed for this purpose.The results of the first simulation study suggest that an SCM can reveal small structures which are hard to distinguish from the background tissue in T2＊W images and the corresponding T2＊ map.The capability of improving the morphological evaluation is likely due to the improvement in the signal-to-noise ratio（SNR） and the carrier-to-noise ratio（CNR） by using the SCM technique.Compared with T2＊ W images,an SCM can improve the SNR by a factor ranging from 1.87 to 2.47.Compared with T2＊ maps,an SCM can improve the SNR by a factor ranging from 3.85 to 33.31.Compared with T2＊W images,an SCM can improve the CNR by a factor ranging from 2.09 to 2.43.Compared with T2＊ maps,an SCM can improve the CNR by a factor ranging from 1.94 to 8.14.For a given noise level,the improvements of the SNR and the CNR depend mainly on the original SNRs and CNRs in T2＊W images,respectively.In vivo experiments confirmed the results of the first simulation study.The results of the second simulation study suggest that more echoes are used to generate the SCM,and higher SNRs and CNRs can be achieved in SCMs.In conclusion,an SCM can provide improved morphological evaluation of T2＊W MR images for renal cancer by unveiling fine structures which are ambiguous or invisible in the corresponding T2＊W MR images and T2＊ maps.Furthermore,in practical applications,for a fixed total sampling time,one should increase the number of echoes as much as possible to achieve SCMs with better SNRs and CNRs.
The stereo vision results from the interaction between geometrical optics and visual psychology.Large depth will bring discomforts for the results of ghosting and flicker.The relevance of the ratio of jumping out depth(RJD)and electroencephalogram(EEG)gravity frequency(GF)was explored to re flect human health under di®erent three-dimensional(3D)depth information(mainly the negative disparity)displayed on a three-dimensional television(3D-TV)with shutter glasses.EEG was obtained from 10 volunteers when they were watching 3D film segments with di®erent negative disparities.The brain GF map shows that the depth information has a stronger in fluence on the frontal lobe than on the occipital lobe.For regression analysis,nonlinear curve fittings of GF to RJD in Fp1,F3,O2 and T5 channels were mainly performed when RJD ranged from 0 to 3.4,while linearfittings were performed in some special RJD ranges.It also confirms that RJD above 2.2 may lead to discomfort to human body.Finally,it suggests a suitable RJD range for people to watch from the objective method.The outcomes can be used as a guidance to decrease human discomforts induced by 3D production.
