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Comparison of 3D MRI with high sampling efficiency and 2D multiplanar MRI for contouring in cervix cancer brachytherapy.

Petric P, Hudej R, Rogelj P, Blas M, Segedin B, Logar HB, Dimopoulos JC - Radiol Oncol (2012)

Bottom Line: When averaged over all delineated slices, the distances between contours in the inter-approach analysis were 2.6 (Standard deviation (SD) 0.4) mm and 2.8 (0.7) mm for observers 1 and 2, respectively.The magnitude of topographic and volumetric inter-observer contouring uncertainties, as obtained on the conventional approach, was maintained on the test approach.This variation was comparable to the inter-approach uncertainties with distances between contours of 3.1 (SD 0.8) and 3.0 (SD 0.7) mm on conventional and test approach, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiotherapy, Institute of Oncology Ljubljana, Ljubljana, Slovenia.

ABSTRACT

Background: MRI sequences with short scanning times may improve accessibility of image guided adaptive brachytherapy (IGABT) of cervix cancer. We assessed the value of 3D MRI for contouring by comparing it to 2D multi-planar MRI.

Patients and methods: In 14 patients, 2D and 3D pelvic MRI were obtained at IGABT. High risk clinical target volume (HR CTV) was delineated by 2 experienced radiation oncologists, using the conventional (2D MRI-based) and test (3D MRI-based) approach. The value of 3D MRI for contouring was evaluated by using the inter-approach and inter-observer analysis of volumetric and topographic contouring uncertainties. To assess the magnitude of deviation from the conventional approach when using the test approach, the inter-approach analysis of contouring uncertainties was carried out for both observers. In addition, to assess reliability of 3D MRI for contouring, the impact of contouring approach on the magnitude of inter-observer delineation uncertainties was analysed.

Results: No approach- or observer - specific differences in HR CTV sizes, volume overlap, or distances between contours were identified. When averaged over all delineated slices, the distances between contours in the inter-approach analysis were 2.6 (Standard deviation (SD) 0.4) mm and 2.8 (0.7) mm for observers 1 and 2, respectively. The magnitude of topographic and volumetric inter-observer contouring uncertainties, as obtained on the conventional approach, was maintained on the test approach. This variation was comparable to the inter-approach uncertainties with distances between contours of 3.1 (SD 0.8) and 3.0 (SD 0.7) mm on conventional and test approach, respectively. Variation was most pronounced at caudal HR CTV levels in both approaches and observers.

Conclusions: 3D MRI could potentially replace multiplanar 2D MRI in cervix cancer IGABT, shortening the overall MRI scanning time and facilitating the contouring process, thus making this treatment method more widely employed.

No MeSH data available.


Related in: MedlinePlus

Bland-Altman inter-observer analysis of the distances between contours for conventional (A) and test (B) approach and for different levels of the contoured volume (all, caudal two, middle and cranial two slices). Full circles: mean values (mm) of the individual distances. Thick dotted lines: limits of agreement (mean ± 2 standard deviations). Thin dotted lines: 95% confidence limits.
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f3-rado-46-03-242: Bland-Altman inter-observer analysis of the distances between contours for conventional (A) and test (B) approach and for different levels of the contoured volume (all, caudal two, middle and cranial two slices). Full circles: mean values (mm) of the individual distances. Thick dotted lines: limits of agreement (mean ± 2 standard deviations). Thin dotted lines: 95% confidence limits.

Mentions: On the inter-observer analysis, high agreement in HR CTV sizes was found for both approaches (Table 1). Favourable mean VCI on conventional approach of 0.76 (SD 0.05) was maintained on test approach (mean VCI: 0.75; SD 0.05). The results of the Bland-Altman analysis of the inter-observer distances between contours were comparable for both approaches and are presented in Table 2 and Figure 3. When averaged over all slices of the HR CTV, mean inter-observer distances between contours of 3.1 mm (SD 0.8 mm) were found on conventional and 3.0 mm (SD 0.7 mm) on test approach. Similar to the inter-approach analysis, highest inter-observer distances were obtained at the caudal level of the HR CTV on the inter-observer assessment and were comparable for both contouring approaches (conventional: 5.4 mm, SD 3.1 mm; test: 4.4 mm, SD 3.0 mm). At the mid and cranial levels of the HR CTV, the inter-observer distances were smaller (Table 2, Figure 3).


Comparison of 3D MRI with high sampling efficiency and 2D multiplanar MRI for contouring in cervix cancer brachytherapy.

Petric P, Hudej R, Rogelj P, Blas M, Segedin B, Logar HB, Dimopoulos JC - Radiol Oncol (2012)

Bland-Altman inter-observer analysis of the distances between contours for conventional (A) and test (B) approach and for different levels of the contoured volume (all, caudal two, middle and cranial two slices). Full circles: mean values (mm) of the individual distances. Thick dotted lines: limits of agreement (mean ± 2 standard deviations). Thin dotted lines: 95% confidence limits.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472953&req=5

f3-rado-46-03-242: Bland-Altman inter-observer analysis of the distances between contours for conventional (A) and test (B) approach and for different levels of the contoured volume (all, caudal two, middle and cranial two slices). Full circles: mean values (mm) of the individual distances. Thick dotted lines: limits of agreement (mean ± 2 standard deviations). Thin dotted lines: 95% confidence limits.
Mentions: On the inter-observer analysis, high agreement in HR CTV sizes was found for both approaches (Table 1). Favourable mean VCI on conventional approach of 0.76 (SD 0.05) was maintained on test approach (mean VCI: 0.75; SD 0.05). The results of the Bland-Altman analysis of the inter-observer distances between contours were comparable for both approaches and are presented in Table 2 and Figure 3. When averaged over all slices of the HR CTV, mean inter-observer distances between contours of 3.1 mm (SD 0.8 mm) were found on conventional and 3.0 mm (SD 0.7 mm) on test approach. Similar to the inter-approach analysis, highest inter-observer distances were obtained at the caudal level of the HR CTV on the inter-observer assessment and were comparable for both contouring approaches (conventional: 5.4 mm, SD 3.1 mm; test: 4.4 mm, SD 3.0 mm). At the mid and cranial levels of the HR CTV, the inter-observer distances were smaller (Table 2, Figure 3).

Bottom Line: When averaged over all delineated slices, the distances between contours in the inter-approach analysis were 2.6 (Standard deviation (SD) 0.4) mm and 2.8 (0.7) mm for observers 1 and 2, respectively.The magnitude of topographic and volumetric inter-observer contouring uncertainties, as obtained on the conventional approach, was maintained on the test approach.This variation was comparable to the inter-approach uncertainties with distances between contours of 3.1 (SD 0.8) and 3.0 (SD 0.7) mm on conventional and test approach, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiotherapy, Institute of Oncology Ljubljana, Ljubljana, Slovenia.

ABSTRACT

Background: MRI sequences with short scanning times may improve accessibility of image guided adaptive brachytherapy (IGABT) of cervix cancer. We assessed the value of 3D MRI for contouring by comparing it to 2D multi-planar MRI.

Patients and methods: In 14 patients, 2D and 3D pelvic MRI were obtained at IGABT. High risk clinical target volume (HR CTV) was delineated by 2 experienced radiation oncologists, using the conventional (2D MRI-based) and test (3D MRI-based) approach. The value of 3D MRI for contouring was evaluated by using the inter-approach and inter-observer analysis of volumetric and topographic contouring uncertainties. To assess the magnitude of deviation from the conventional approach when using the test approach, the inter-approach analysis of contouring uncertainties was carried out for both observers. In addition, to assess reliability of 3D MRI for contouring, the impact of contouring approach on the magnitude of inter-observer delineation uncertainties was analysed.

Results: No approach- or observer - specific differences in HR CTV sizes, volume overlap, or distances between contours were identified. When averaged over all delineated slices, the distances between contours in the inter-approach analysis were 2.6 (Standard deviation (SD) 0.4) mm and 2.8 (0.7) mm for observers 1 and 2, respectively. The magnitude of topographic and volumetric inter-observer contouring uncertainties, as obtained on the conventional approach, was maintained on the test approach. This variation was comparable to the inter-approach uncertainties with distances between contours of 3.1 (SD 0.8) and 3.0 (SD 0.7) mm on conventional and test approach, respectively. Variation was most pronounced at caudal HR CTV levels in both approaches and observers.

Conclusions: 3D MRI could potentially replace multiplanar 2D MRI in cervix cancer IGABT, shortening the overall MRI scanning time and facilitating the contouring process, thus making this treatment method more widely employed.

No MeSH data available.


Related in: MedlinePlus