Comparison of Magnetic Resonance Imaging–Based and Conventional Measurements for Proton Beam Therapy of Uveal Melanoma

Automatic Three-Dimensional Magnetic Resonance-based measurements of tumour prominence and basal diameter for treatment planning of uveal melanoma

“…3DT1gd and 3DT2-weighted images, both with acquisition voxel size of 0.8 × 0.8 × 0.8 mm 3 , were acquired to an earlier described protocol [15] , [16] . Ultrasound images were obtained by an ocular oncologist [25] . Details on image acquisition are further described in the Supplementary Materials .…”

“…In order to assess how these automatic 3D measurements relate to the currently used manual assessments, the prominence and LBD were measured manually on the T1gd-weighted images. For the prominence, the clinical measurement was used, measured perpendicular to the sclera [25] . For the LBD, the measurements were repeated on the delineated tumour contour, to avoid the confounding effect of a different tumour boundary interpretation [27] .…”

“…Furthermore, the automatic T1gd and clinical ultrasound measurements were compared for prominence, LBD and SBD. For the prominence, differences > 0.5 mm and for the diameters, differences > 1.0 mm were considered clinically significant [25] . Medians and 25th–75th percentiles of the automatic-manual, T1gd-T2 and T1gd-ultrasound differences were assessed, as non-normality was demonstrated with a Shapiro-Wilk test (e.g.…”

“…due to a flat tumour or a limited penetration depth or limited field of view (FOV) of the ultrasound transducer, were marked ( Supplementary Fig. 2 ) [25] .…”

“…Although the 3D visualisation of the tumour of MRI allows for a more comprehensive assessment of tumour geometry [18] , tumour dimension measurements can be performed in different planes, resulting in different possible prominence and diameter measurements, especially for complexly shaped tumours ( Fig. 1 ) [19] , [25] . Additionally, manual measurement of prominence and LBD on MRI is reported to be difficult and time-consuming [26] .…”