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 2 Number of cases out of 27 exposures with significant ADC changes (greater than ±2.1% limits of agreement estimates, established from the pairs of baseline measurements) at each of the evaluated time intervals

Time after sonication (min)	Number of cases out of 27 with significant ADC change
< 1	26^a
1–5	26
6–10	22
11–15	21
16–20	17
21–50	13^b

^a Diffusion-weighted imaging (DWI) data were not available in one case due to a slightly prolonged mandatory cooling time
^b DWI data were not available in five cases because exposures were made close to the end of the imaging session
These data show that apparent diffusion coefficient (ADC) increases were always significant immediately after exposure, and that significant changes persisted more than 20 min after exposure in half of the cases