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Follow-up assessment of vestibular schwannomas: volume quantification versus two-dimensional measurements.

van de Langenberg R, de Bondt BJ, Nelemans PJ, Baumert BG, Stokroos RJ - Neuroradiology (2009)

Bottom Line: Two-dimensional and volume measurements both showed best reproducibility on CE T1-weighted images.Volume measurements are more accurate compared to two-dimensional measurements for the evaluation of VS growth.SDD (%) strongly depends on VS size.

View Article: PubMed Central - PubMed

Affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands. rickvandelangenberg@hotmail.com

ABSTRACT

Introduction: A conservative treatment strategy is often proposed as a primary treatment option in the management of vestibular schwannomas (VS). In this "wait and scan" policy, audiovestibular symptoms are monitored regularly, and VS growth is measured on consecutive magnetic resonance images (MRI). The aim of this study is validation of two-dimensional versus volume MRI assessment in the longitudinal follow-up of VS and to define tumor growth beyond measurement error.

Methods: MRI scans of 68 consecutive patients with VS were analyzed retrospectively. Two-dimensional and volume measurements on contrast enhanced (CE) T1- and T2-weighted images were performed independently by two readers. Smallest detectable differences (SDD) were calculated, and intraclass correlation coefficients (ICCs) were determined for both assessment methods.

Results: Two-dimensional and volume measurements both showed best reproducibility on CE T1-weighted images. SDD for differences relative to baseline MRI [SDD (%)] for two-dimensional measurements had a higher interobserver error compared to volume measurements (40% versus 19.7%), which decreases when tumor size increases. The ICC for two-dimensional measurements in three directions was 0.947, 0.974, and 0.978 and for volume measurements 0.999.

Conclusion: Volume measurements are more accurate compared to two-dimensional measurements for the evaluation of VS growth. These measurements are assessed preferably on CE T1-weighted images. SDD (%) strongly depends on VS size. SDD between consecutive scans exceeds the common clinical applied criterion of 1 or 2 mm growth to define growth.

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Bland and Altman plot of baseline two-dimensional maximum craniocaudal (CC) dimension measurements on contrast-enhanced T1-weighted images (CE T1-WI). The values on the Y-axis represent the measurement differences between the two readers and their mean difference (thin line). The values on the X-axis represent the mean of both measurements. The thick black lines represent the 95% limits of agreement. Interobserver differences are larger in smaller vestibular schwannomas
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Fig3: Bland and Altman plot of baseline two-dimensional maximum craniocaudal (CC) dimension measurements on contrast-enhanced T1-weighted images (CE T1-WI). The values on the Y-axis represent the measurement differences between the two readers and their mean difference (thin line). The values on the X-axis represent the mean of both measurements. The thick black lines represent the 95% limits of agreement. Interobserver differences are larger in smaller vestibular schwannomas

Mentions: Bland and Altman plots were constructed using data of the baseline MR images of the 165 scans from 68 patients (Figs. 3 and 4). The SD for each reader (A and B) and the SD of the mean difference between readers are presented in Table 1. The SDD and SDD (%) for absolute differences and differences relative to baseline MR images, respectively, are presented in Table 2. In Table 3, we present the ICC with 95% confidence intervals.Fig. 3


Follow-up assessment of vestibular schwannomas: volume quantification versus two-dimensional measurements.

van de Langenberg R, de Bondt BJ, Nelemans PJ, Baumert BG, Stokroos RJ - Neuroradiology (2009)

Bland and Altman plot of baseline two-dimensional maximum craniocaudal (CC) dimension measurements on contrast-enhanced T1-weighted images (CE T1-WI). The values on the Y-axis represent the measurement differences between the two readers and their mean difference (thin line). The values on the X-axis represent the mean of both measurements. The thick black lines represent the 95% limits of agreement. Interobserver differences are larger in smaller vestibular schwannomas
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2710491&req=5

Fig3: Bland and Altman plot of baseline two-dimensional maximum craniocaudal (CC) dimension measurements on contrast-enhanced T1-weighted images (CE T1-WI). The values on the Y-axis represent the measurement differences between the two readers and their mean difference (thin line). The values on the X-axis represent the mean of both measurements. The thick black lines represent the 95% limits of agreement. Interobserver differences are larger in smaller vestibular schwannomas
Mentions: Bland and Altman plots were constructed using data of the baseline MR images of the 165 scans from 68 patients (Figs. 3 and 4). The SD for each reader (A and B) and the SD of the mean difference between readers are presented in Table 1. The SDD and SDD (%) for absolute differences and differences relative to baseline MR images, respectively, are presented in Table 2. In Table 3, we present the ICC with 95% confidence intervals.Fig. 3

Bottom Line: Two-dimensional and volume measurements both showed best reproducibility on CE T1-weighted images.Volume measurements are more accurate compared to two-dimensional measurements for the evaluation of VS growth.SDD (%) strongly depends on VS size.

View Article: PubMed Central - PubMed

Affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands. rickvandelangenberg@hotmail.com

ABSTRACT

Introduction: A conservative treatment strategy is often proposed as a primary treatment option in the management of vestibular schwannomas (VS). In this "wait and scan" policy, audiovestibular symptoms are monitored regularly, and VS growth is measured on consecutive magnetic resonance images (MRI). The aim of this study is validation of two-dimensional versus volume MRI assessment in the longitudinal follow-up of VS and to define tumor growth beyond measurement error.

Methods: MRI scans of 68 consecutive patients with VS were analyzed retrospectively. Two-dimensional and volume measurements on contrast enhanced (CE) T1- and T2-weighted images were performed independently by two readers. Smallest detectable differences (SDD) were calculated, and intraclass correlation coefficients (ICCs) were determined for both assessment methods.

Results: Two-dimensional and volume measurements both showed best reproducibility on CE T1-weighted images. SDD for differences relative to baseline MRI [SDD (%)] for two-dimensional measurements had a higher interobserver error compared to volume measurements (40% versus 19.7%), which decreases when tumor size increases. The ICC for two-dimensional measurements in three directions was 0.947, 0.974, and 0.978 and for volume measurements 0.999.

Conclusion: Volume measurements are more accurate compared to two-dimensional measurements for the evaluation of VS growth. These measurements are assessed preferably on CE T1-weighted images. SDD (%) strongly depends on VS size. SDD between consecutive scans exceeds the common clinical applied criterion of 1 or 2 mm growth to define growth.

Show MeSH
Related in: MedlinePlus