Quantitative Elastography for Cervical Stiffness Assessment during Pregnancy
Figure 2
Reliability of tissue strain measurement. Plots (a), (b), (c), (d), (e), and (f) (per protocol analysis): the Bland-Altman plots demonstrate the degree of concordance between the pairs of cervical TSs. The region of agreement is included inside the two standard deviations interval from the mean of differences. The space included between the zero dotted lines and the mean of differences represents the bias. The gray band, where plotted, represents the 95% confidence interval of the mean of differences. F and S refer to the operator undergoing the TS calculation; f and s refer to the operator undergoing the raw data acquirement, where and and and refer, respectively, to the first and second raw data sets. (a) The intraobserver variability of the TS calculation of the same raw data (F/F) is shown. (b) The interobserver variability of the TS calculation of the same raw data by the two investigators (F/S) is depicted. (c) The interobserver variability of the TS calculation of the same raw data (F/S) is shown. (d) The intraobserver variability of the raw data acquisition and calculation (F-F) is shown. (e) The interobserver variability of the raw data acquisition with two raw data sets acquired by different investigators (f and s) and calculated by the same investigator is presented (F/F). (f) The interobserver variability of the raw data acquisition and calculation by the two investigators is indicated (F/S). Plots (g), (h), and (i) (other analysis): the Bland-Altman plots demonstrate the degree of concordance between the pairs of cervical TSs. (g) The interobserver variability of the TS calculation: in this plot, we analyse all data from Figures 2(b) and 2(c) (i.e., F/S and F/S). (h) The interobserver variability of the raw data acquirement: the two raw data sets acquired by the two investigators (F and S) are measured by the same investigator (F/F and S/S). (i) The interobserver variability of the raw data acquirement and calculation is shown (F-F/S, yielding an average of the 2 raw data and ). In this analysis we took into consideration the average of the raw data measurements of investigator F versus the TS acquisition and measurement of one raw data set by investigator S.
