ABSTRACT
OBJECTIVE: To investigate the feasibility of tissue similarity map (TSM)-based relative cerebral blood volume (rCBV) assessment in evaluating the hemodynamic characteristics of gliomas and in differentiating high-grade gliomas from low-grade ones without concentration time curve (CTC). MATERIALS AND METHODS: TSM-based rCBV (rCBV TSM ) and conventional rCBV (rCBV PWI ) maps were generated (n = 35). The differences in percentage and concordance correlation coefficient (CCC) of the rCBV TSM and rCBV PWI ratios were calculated. The Mann-Whitney test and the receiver operating characteristic (ROC) curve analysis were also performed to examine the relationships of rCBV ratios between high- and low-grade gliomas. The improvement factors of signal to noise ratio (SNR) of rCBV TSM maps were also calculated. RESULTS: The mean difference in percentage between rCBV TSM and rCBV PWI ratios was 4.29 ± 2.62%. The CCC of rCBV TSM and rCBV PWI ratios was 0.9974, with 95% confidence interval of 0.9948, 0.9987, which implied a high agreement between them. The Mann-Whitney test suggested that the rCBV TSM and rCBV PWI ratios of high-grade gliomas were significantly different from those of low-grade gliomas (P < 0.001). The improvement factors of SNR of the rCBV TSM map were 1.31 ± 0.24 for glioma and 1.28 ± 0.24 for normal white matter. CONCLUSION: It is feasible to use rCBV TSM in the evaluation of hemodynamic characteristics of gliomas and differentiation of high- and low-grade gliomas without CTC. Moreover, rCBV TSM maps possess a higher SNR, which allows potentially more accurate diagnosis compared with the conventional ones.
ABSTRACT
OBJECTIVE: To evaluate the feasibility of low radiation exposure and low contrast medium volume for coronary CT angiography with High- pitch spiral acquisition mode of dual source CT. METHODS: 135 patients whose BMI <23 kg/m² and heart rates <65 bpm selected from 291 patients diagnosed of suspected CHD at our institution from September 2013 to February 2014 were randomly divided into 3 groups before CCTA, and there were 45 patients in each group. 80 kV , Iodixanol (320 mgI/ml) and sinogram affirmed iterative reconstruction (SAFIRE) were used in A group. 80 kV , Iopamidol (370 mgI/ml) and SAFIRE were used in B group. 100 kV, Iodixanol and filtered back projection (FBP) were used in C group. Two radiologists assessed image quality with 5-piont scale subjectively and double-blind. Independent-Sample Test was used to analyze statistical significance of image quality including signal to noise ratio(SNR) and contrast to noise ratio (CNR) between A and B group or between A and C group. At the same time, Contrast medium dose statistical significance between A and B group and mean effective Radiation dose (ED)statistical significance between A and C were analyzed by the same way. RESULTS: There were no significant difference of image quality including SNR and CNR of aortic root (AO), left main coronary artery (LM), left anterior descending artery (LAD), circumflex coronary artery (CX) and right coronary artery (RCA) Between A and B group (P = non-significant for all comparison), whereas Iodine in taken of A group decreased 14% (17 600 mg vs 20 350 mg). There were no significant difference of image quality including SNR and CNR of AO, LM, LAD, CX and RCA Between A and C group (P = non-significant for all comparison), whereas mean ED of A group decreased 50% (0.41 ± 0.05 mSv vs 0.79 ± 0.15 mSv). CONCLUSION: The double low dose application which use High-pitch spiral mode, 80 kV, SAFIRE, and Iodixanol (320 mgI/ml) can be used in those patients whose BMI <23 kg/m² and heart rates <65 bpm to reduce the burden of radiation and contrast medium significantly, without compromising the image quality.
