Table 2. Changes in mean volume and volume overlap index (VOI) of the prostate and prostate plus seminal vesicles in the different set-ups. The p-values refer to the differences in the prostate and prostate plus seminal vesicles volumes delineated on the CTS to those drawn using the CT–MRID or CT–MRIRT.
| CT–MRID | CT–MRIRT | ||||
| Structure | Mean CTS volume ± SD (cm3) | Mean volume ± SD in cm3 (p-value) | Mean VOI | Mean volume ± SD in cm3 (p-value) | Mean VOI (cm3) |
| Prostate | 36.3±10.8 | 32.0±11.1 (0.001) | 0.70 | 31.4±11.0 (0.001) | 0.74 |
| Prostate and seminal vesicles | 45.9±12.0 | 41.2±12.9 (0.001) | 0.64 | 40.3±12.5 (0.002) | 0.69 |
CTS, CT with the diagnostic MRI scan viewed on a separate console; CT–MRID, CT registered with the diagnostic MRI scan; CT–MRIRT, CT registered with the MRI scan in the radiotherapy position; SD, standard deviation.