Fig 4. Scatterplots show higher correlation between rCBV ratios and both cell density (n = 33, r = 0.57, P < .001) (A) and microvessel density (n = 33, r = 0.46, P < .01) (B) in bulk tumor than in the whole set of samples (Fig 3). In bulk tumor, there is no significant correlation between ADC ratios and cell density (n = 33, r = –0.20, P = .26) (C), whereas an inverse correlation between ADC and microvessel density is found (n = 33, r = –0.36, P < .05) (D). Spearman rank correlation test was used, and P < .05 was considered to be statistically significant.