Table 2.

HRCTV volume and dimensions for fractions 2-4 for the three imaging approaches

HRCTV	Fr	MRI (A)	MRI1st/CT (B)	CT (C)	Approach A vs. B			Approach A vs. C			Approach B vs. C
		Mean ± SD	Mean ± SD	Mean ± SD	Mean diff	SE	p-value	Mean diff	SE	p-value	Mean diff	SE	p-value
Volume	2	19.0 ±7.3	20.5 ±7.0	27.7 ±9.6	–1.53	0.95	0.42	–8.70	1.33	0.00*	–7.17	1.35	0.00*
	3	18.8 ±6.9	20.7 ±6.9	26.7 ±8.8	–1.86	0.58	0.31	–7.93	1.32	0.00*	–6.06	1.31	0.00*
	4	18.4 ±6.7	21.8 ±6.9	26.3 ±10.1	–3.41	1.04	0.03*	–7.92	0.74	0.00*	–4.51	1.71	0.03*
Width (maximum)	2	4.1 ±0.4	4.1 ±0.6	4.3 ±0.6	–0.03	0.11	1.00	–0.25	0.12	0.07	–0.23	0.10	0.06
	3	4.2 ±0.5	4.1 ±0.5	4.3 ±0.3	0.11	0.10	0.83	–0.11	0.21	0.60	–0.20	0.19	0.33
	4	4.1 ±0.4	4.2 ±0.5	4.4 ±0.6	–0.06	0.11	1.00	–0.30	0.14	0.06	–0.28	0.09	0.02*
Width (point A)	2	2.7 ±0.8	3.0 ±0.8	3.2 ±0.6	–0.27	0.22	0.74	–0.55	0.21	0.03*	–0.27	0.17	0.15
	3	2.6 ±0.6	2.8 ±0.7	3.2 ±0.8	–0.25	0.17	0.54	–0.76	0.24	0.01*	–0.49	0.15	0.01*
	4	2.6 ±0.6	2.8 ±0.5	3.1 ±0.9	–0.26	0.14	0.32	–0.56	0.17	0.01*	–0.29	0.16	0.10
Height	2	2.7 ±0.7	2.8 ±0.6	3.2 ±0.4	–0.13	0.11	0.84	–0.53	0.18	0.02*	–0.40	0.20	0.08
	3	2.9 ±0.7	2.9 ±0.6	3.3 ±0.5	0.01	0.09	1.00	–0.46	0.16	0.02*	–0.47	0.14	0.01*
	4	2.7 ±0.7	2.8 ±0.6	3.3 ±0.4	–0.10	0.15	1.00	–0.62	0.23	0.03*	–0.52	0.15	0.01*

HRCTV – high-risk clinical target volume; MRI – magnetic resonance imaging; CT – computed tomography; Fr – fraction; SD – standard deviation; mean diff – mean difference; SE – standard error

^*statistically significant (p < 0.05)