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The main limitation of our study was the use of only one ultrasound machine, which did not provide equally high accuracy, as in previous studies [ 2 ]. We found that the diagnostic performance of the first echography machine was limited (sensitivity 63.6%, specificity 84.5%) compared with that of the other machines (sensitivity 88.9%, specificity 95.9%). Omission of the first echography may have overestimated the accuracy of echography in our study. It seems that the first machine provided variable accuracy, as its diagnostic performance was higher when the final diagnosis was grade IV gliomas (sensitivity 100%) than grade III gliomas (sensitivity 50%; specificity 100%), and its predictive value was higher when excluding both low- and high-grade gliomas from the pathological analysis (sensitivity 91.7%, specificity 83.3%). Therefore, we decided to omit the first echography machine, which lacked consistency in its diagnostic performance and in the data gathered. However, several other studies that evaluated the performance of echography have considered only the first machine [ 40 ],[ 41 ],as the final diagnosis was confirmed with other diagnostic tests or other available data. We found that this machine provided adequate performance with a sensitivity of 91.7%, and we used this as the reference standard. A second limitation was our use of CE and CEA staining for immunohistochemical analysis. Previous studies have reported that CE3B and CEA are not prognostic factors in gliomas, in contrast to NSE, S-100, and GFAP [ 42 ]. However, as the specimens were collected in 2004, we selected markers of which the prognostic value has been previously described. Furthermore, CE3B, CEA, and GFAP staining appeared to be complementary, with each marker being suggestive of different histological features, confirming the validity of our results. Given the power of this study, it is unlikely that these factors could have influenced our findings. The known prognostic value of the Ki-67 antigen, although not significant in our analysis, is supported by the consistency of our results with previous studies. This factor could be an alternative in the assessment of grade of gliomas and it is not expected to be prognostic in most cases of GBMs (10% of GBM cases). It seems that tumor grade and Ki-67 could be complementary in assessing malignancy. The low accuracy and the lower predictive value for tumor grade of rCBV (31%) in comparison with other MRI techniques analyzed are in concordance with previous studies [ 43 ] and with the reduced sensitivity (11%) reported in other studies when including only grade IV gliomas [ 2 ],[ 44 ]. It seems that rCBV is highly reliable in terms of differentiation between low and high grade gliomas, but not between high and low grade gliomas. As MBP is diffusely expressed in all glial cells and has been reported as a marker of glial proliferation [ 45 ],[ 46 ], we believe that this positive expression may make some cases of low-grade gliomas appear more hypercellular than others, thus increasing the accuracy of diagnosis of grade III gliomas by MBP; however, our study did not demonstrate this effect. Furthermore, the high accuracy of rADC could be related to the fact that this parameter is differentially expressed according to the type of cell. It appears that increased amounts of lipids may increase the cellularity of glial cells, enhancing the contrast of tumors. However, our study found a reduction of cellularity and lipids when calculating this parameter. It seems that rADC was not sensitive enough for the evaluation of this parameter. 3d9ccd7d82