Value of diffusion-weighted imaging for monitoring tissue change during magnetic resonance-guided high-intensity focused ultrasound therapy in bone applications: an ex-vivo study

European Radiology Experimental

Table 3 Correlations between percentage change in apparent diffusion coefficient (ADC) and applied acoustic energy, thermal dose volume (V_240EM), and maximum temperature, showing that statistical significance was achieved at every measured time point, although the strength of the correlations varied

Time after sonication (min)	Correlation between % change in mean ADC and:
Time after sonication (min)	Applied acoustic energy	V_240EM^a	Maximum temperature
< 1	r = 0.73	ρ = 0.61	r = 0.50
< 1	p < 0.001	p = 0.001	p = 0.010
1–5	r = 0.85	ρ = 0.80	r = 0.57
1–5	p < 0.001	p < 0.001	p = 0.002
6–10	r = 0.55	ρ = 0.48	r = 0.44
6–10	p = 0.003	p = 0.011	p = 0.023
11–15	r = 0.77	ρ = 0.73	r = 0.53
11–15	p < 0.001	p < 0.001	p = 0.005
16–20	r = 0.77	ρ = 0.76	r = 0.53
16–20	p < 0.001	p < 0.001	p = 0.005
21–50	r = 0.66	ρ = 0.52	r = 0.60
21–50	p = 0.001	p = 0.011	p = 0.003

^a Non-parametric Spearman’s test was used to correlate non-normally distributed V_240EM data