Relationship between segmented volume (Vsegmented) and estimated tumour volumes. V6 had the highest agreement with the segmented volume, with concordance correlation coefficients (CCC) of 0.96 [95%CI: 0.95–0.97]. CCCs for V2, V3, V4 and V5 were 0.74 [95%CI: 0.70 to 0.77], 0.80 [95%CI: 0.77 to 0.83], 0.92 [95%CI: 0.91–0.94] and 0.93 [95%CI: 0.91–0.94] respectively. The agreement was lowest for V1, with CCC of 0.65 [95%CI: 0.61–0.69]