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Reproducibility of Middle Cerebral Artery Stenosis Measurements by DSA: Comparison of the NASCET and WASID Methods.

Chen L, Zhan Q, Ma C, Liu Q, Zhang X, Tian X, Jiang Y, Dong Y, Chen S, Lu J - PLoS ONE (2015)

Bottom Line: Intra- and inter-observer variability of the two methods was evaluated by intraclass correlation coefficient (ICC), Spearman's R value, Pearson correlation coefficient and Bland-Altman plots.Intra-observer measurements showed good or excellent agreement with respect to WASID and NASCET evaluation (ICC, 0.656 to 0.817 and 0.635 to 0.761, respectively).Good agreement for the WASID evaluation (ICC, 0.592 to 0.628) and for the NASCET evaluation (ICC, 0.529 to 0.568) was observed for inter-observer measurements.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Changhai Hospital of Shanghai, The Second Military Medical University, No. 168 Changhai Road, Shanghai, 200433, China.

ABSTRACT

Purpose: To evaluate the intra- and inter-observer variability of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) criteria for the evaluation of middle cerebral artery (MCA) stenosis using digital subtraction angiography (DSA).

Materials and methods: DSA images of 114 cases with 131 stenotic MCAs were retrospectively analyzed. Two radiologists and a researcher measured the degree of MCA stenosis independently using both NASCET and WASID methods. To determine intra-observer agreement, all the observers reevaluated the degree of MCA stenosis 4 weeks later. The linear relation and coefficient of variation (CV) between the measurements made by the two methods were assessed by correlation coefficient and multi-factor analysis of variance (ANOVA), respectively. Intra- and inter-observer variability of the two methods was evaluated by intraclass correlation coefficient (ICC), Spearman's R value, Pearson correlation coefficient and Bland-Altman plots.

Results: Despite the fact that the degree of MCA stenosis measured by NASCET was lower than measured using the WASID method, there was good linear correlation between the measurements made by the two methods (for the mean measurements of the 3 observers, NASCET% = 0.891 × WASID% - 1.89%; ICC, Spearman's R value and Pearson correlation were 0.874, 0.855, and 0.874, respectively). The CVs of both intra- and inter-observer measurements of MCA stenosis using WASID were significantly lower than that using NASCET confirmed by the multi-factor ANOVA results, which showed only the measurement methods of MCA stenosis had significant effects on the CVs both in intra- and inter-observer measurements (both P values < 0.001). Intra-observer measurements showed good or excellent agreement with respect to WASID and NASCET evaluation (ICC, 0.656 to 0.817 and 0.635 to 0.761, respectively). Good agreement for the WASID evaluation (ICC, 0.592 to 0.628) and for the NASCET evaluation (ICC, 0.529 to 0.568) was observed for inter-observer measurements. Bland-Altman plots demonstrated that the WASID method had better reproducibility and intra-observer agreement than NASCET method for evaluating MCA stenosis.

Conclusion: Both NASCET and WASID methods have an acceptable level of agreement; however, the WASID method had better reproducibility for the evaluation of MCA stenosis, and thus the WASID method may serve as a standard for measuring the degree of MCA stenosis.

No MeSH data available.


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Bland-Altman plots of intra-observer reproducibility of the NASCET and WASID methods.(A, C and E) WASID method for Observer 1, 2 and 3, respectively. (B, D and F) NASCET method for Observer 1, 2 and 3, respectively.
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pone.0130991.g003: Bland-Altman plots of intra-observer reproducibility of the NASCET and WASID methods.(A, C and E) WASID method for Observer 1, 2 and 3, respectively. (B, D and F) NASCET method for Observer 1, 2 and 3, respectively.

Mentions: Statistical results of intra-observer reproducibility are presented in Table 2. Intra-observer measurements showed good or excellent agreement both for the NASCET evaluation and the WASID evaluation using ICC (0.635 to 0.761 and 0.656 to 0.817, respectively, P < 0.01). Spearman’s R value and Pearson correlation coefficient also suggested a high correlation in intra-observer measurements. The bias and limits of agreement of intra-observer agreement for the measurements of MCA stenosis by using NASCET and WASID methods by employing Bland-Altman plots (Fig 3) were provided in Table 3 (Intra-observer variability). Compared with NASCET, WASID has lower bias and limits of agreement (Table 3) and the narrower the dispersion of the scatterplot at a given measurement (Fig 3). In addition, the WASID method showed better reproducibility than the NASCET method for evaluating of MCA stenosis with a higher ICC (0.791 versus 0.684 for 1st observer, 0.656 versus 0.635 for 2nd observer and 0.817 versus 0.761 for 3rd observer), Spearman’s R value (0.792 versus 0.681 for 1st observer, 0.649 versus 0.624 for 2nd observer and 0.814 versus 0.756 for 3rd observer), and Pearson correlation coefficient (0.791 versus 0.684 for 1st observer, 0.657 versus 0.636 for 2nd observer and 0.818 versus 0.762 for 3rd observer), respectively. Moreover, multi-factor ANOVA results showed the CVs of intra-observer measurements using WASID method were significantly lower than that using NASCET (Table 4) in all of the 3 observers (P < 0.001). Observer had no significant effects on the CVs of MCA stenosis in intra-observer measurements (P = 0.406).


Reproducibility of Middle Cerebral Artery Stenosis Measurements by DSA: Comparison of the NASCET and WASID Methods.

Chen L, Zhan Q, Ma C, Liu Q, Zhang X, Tian X, Jiang Y, Dong Y, Chen S, Lu J - PLoS ONE (2015)

Bland-Altman plots of intra-observer reproducibility of the NASCET and WASID methods.(A, C and E) WASID method for Observer 1, 2 and 3, respectively. (B, D and F) NASCET method for Observer 1, 2 and 3, respectively.
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pone.0130991.g003: Bland-Altman plots of intra-observer reproducibility of the NASCET and WASID methods.(A, C and E) WASID method for Observer 1, 2 and 3, respectively. (B, D and F) NASCET method for Observer 1, 2 and 3, respectively.
Mentions: Statistical results of intra-observer reproducibility are presented in Table 2. Intra-observer measurements showed good or excellent agreement both for the NASCET evaluation and the WASID evaluation using ICC (0.635 to 0.761 and 0.656 to 0.817, respectively, P < 0.01). Spearman’s R value and Pearson correlation coefficient also suggested a high correlation in intra-observer measurements. The bias and limits of agreement of intra-observer agreement for the measurements of MCA stenosis by using NASCET and WASID methods by employing Bland-Altman plots (Fig 3) were provided in Table 3 (Intra-observer variability). Compared with NASCET, WASID has lower bias and limits of agreement (Table 3) and the narrower the dispersion of the scatterplot at a given measurement (Fig 3). In addition, the WASID method showed better reproducibility than the NASCET method for evaluating of MCA stenosis with a higher ICC (0.791 versus 0.684 for 1st observer, 0.656 versus 0.635 for 2nd observer and 0.817 versus 0.761 for 3rd observer), Spearman’s R value (0.792 versus 0.681 for 1st observer, 0.649 versus 0.624 for 2nd observer and 0.814 versus 0.756 for 3rd observer), and Pearson correlation coefficient (0.791 versus 0.684 for 1st observer, 0.657 versus 0.636 for 2nd observer and 0.818 versus 0.762 for 3rd observer), respectively. Moreover, multi-factor ANOVA results showed the CVs of intra-observer measurements using WASID method were significantly lower than that using NASCET (Table 4) in all of the 3 observers (P < 0.001). Observer had no significant effects on the CVs of MCA stenosis in intra-observer measurements (P = 0.406).

Bottom Line: Intra- and inter-observer variability of the two methods was evaluated by intraclass correlation coefficient (ICC), Spearman's R value, Pearson correlation coefficient and Bland-Altman plots.Intra-observer measurements showed good or excellent agreement with respect to WASID and NASCET evaluation (ICC, 0.656 to 0.817 and 0.635 to 0.761, respectively).Good agreement for the WASID evaluation (ICC, 0.592 to 0.628) and for the NASCET evaluation (ICC, 0.529 to 0.568) was observed for inter-observer measurements.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Changhai Hospital of Shanghai, The Second Military Medical University, No. 168 Changhai Road, Shanghai, 200433, China.

ABSTRACT

Purpose: To evaluate the intra- and inter-observer variability of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) criteria for the evaluation of middle cerebral artery (MCA) stenosis using digital subtraction angiography (DSA).

Materials and methods: DSA images of 114 cases with 131 stenotic MCAs were retrospectively analyzed. Two radiologists and a researcher measured the degree of MCA stenosis independently using both NASCET and WASID methods. To determine intra-observer agreement, all the observers reevaluated the degree of MCA stenosis 4 weeks later. The linear relation and coefficient of variation (CV) between the measurements made by the two methods were assessed by correlation coefficient and multi-factor analysis of variance (ANOVA), respectively. Intra- and inter-observer variability of the two methods was evaluated by intraclass correlation coefficient (ICC), Spearman's R value, Pearson correlation coefficient and Bland-Altman plots.

Results: Despite the fact that the degree of MCA stenosis measured by NASCET was lower than measured using the WASID method, there was good linear correlation between the measurements made by the two methods (for the mean measurements of the 3 observers, NASCET% = 0.891 × WASID% - 1.89%; ICC, Spearman's R value and Pearson correlation were 0.874, 0.855, and 0.874, respectively). The CVs of both intra- and inter-observer measurements of MCA stenosis using WASID were significantly lower than that using NASCET confirmed by the multi-factor ANOVA results, which showed only the measurement methods of MCA stenosis had significant effects on the CVs both in intra- and inter-observer measurements (both P values < 0.001). Intra-observer measurements showed good or excellent agreement with respect to WASID and NASCET evaluation (ICC, 0.656 to 0.817 and 0.635 to 0.761, respectively). Good agreement for the WASID evaluation (ICC, 0.592 to 0.628) and for the NASCET evaluation (ICC, 0.529 to 0.568) was observed for inter-observer measurements. Bland-Altman plots demonstrated that the WASID method had better reproducibility and intra-observer agreement than NASCET method for evaluating MCA stenosis.

Conclusion: Both NASCET and WASID methods have an acceptable level of agreement; however, the WASID method had better reproducibility for the evaluation of MCA stenosis, and thus the WASID method may serve as a standard for measuring the degree of MCA stenosis.

No MeSH data available.


Related in: MedlinePlus