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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.


Related in: MedlinePlus

Digital subtraction angiography image showing the points where measurements were taken.The NASCET method uses the distal segment as a comparator to the stenotic region. The WASID method divides the stenotic segment measurement by the proximal normal segment.
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pone.0130991.g001: Digital subtraction angiography image showing the points where measurements were taken.The NASCET method uses the distal segment as a comparator to the stenotic region. The WASID method divides the stenotic segment measurement by the proximal normal segment.

Mentions: All measurements of luminal stenosis were performed by three independent observers: two radiologists (referred to as Observer 1 and 2, respectively) with 5 years of experience in neuroradiology, and one researcher (referred to as Observer 3) with 4 years of experience in neuroradiology, who were blinded to the clinical information of each patient. An electronic ruler from industry-standard Digital Imaging and Communications in Medicine reading software (General Electric Advantage Work-station, GE Healthcare, Milwaukee, WI, USA) configured on a physician workstation with a technical high resolution screen (Jusha Healthcare, Nanjing, People’s Republic of China) was used to measure vessel diameters on the anteroposterior view of DSA images. The images were zoomed to 250%, and window width and level were adjusted to optimize vessel contour. The degree of stenosis or the ratio between the residual lumen at the stenosis and the normal lumen without stenosis was determined using both NASCET and WASID criteria (Fig 1). To evaluate intra-observer variability, three observers measured MCA stenosis twice during two different sessions that were separated by at least 4-week interval to avoid any recall bias. All of the observers were blinded to theirs and each other’s results.


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)

Digital subtraction angiography image showing the points where measurements were taken.The NASCET method uses the distal segment as a comparator to the stenotic region. The WASID method divides the stenotic segment measurement by the proximal normal segment.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4482749&req=5

pone.0130991.g001: Digital subtraction angiography image showing the points where measurements were taken.The NASCET method uses the distal segment as a comparator to the stenotic region. The WASID method divides the stenotic segment measurement by the proximal normal segment.
Mentions: All measurements of luminal stenosis were performed by three independent observers: two radiologists (referred to as Observer 1 and 2, respectively) with 5 years of experience in neuroradiology, and one researcher (referred to as Observer 3) with 4 years of experience in neuroradiology, who were blinded to the clinical information of each patient. An electronic ruler from industry-standard Digital Imaging and Communications in Medicine reading software (General Electric Advantage Work-station, GE Healthcare, Milwaukee, WI, USA) configured on a physician workstation with a technical high resolution screen (Jusha Healthcare, Nanjing, People’s Republic of China) was used to measure vessel diameters on the anteroposterior view of DSA images. The images were zoomed to 250%, and window width and level were adjusted to optimize vessel contour. The degree of stenosis or the ratio between the residual lumen at the stenosis and the normal lumen without stenosis was determined using both NASCET and WASID criteria (Fig 1). To evaluate intra-observer variability, three observers measured MCA stenosis twice during two different sessions that were separated by at least 4-week interval to avoid any recall bias. All of the observers were blinded to theirs and each other’s results.

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