Magnetic resonance imaging VVF was correlated to other histological measures including Ki-67 (proliferative index) and viable gland index (VGD). A–D, Histological analysis demonstrated increased areas of confluent necrosis with increased glandular component, resulting in decreased viable gland index in cyclopamine- (B), Ab5E1- (C), and forskolin-treated (D) animals relative to control (A). E–H, Histological analysis for proliferative index demonstrated a decreased proportion of Ki-67–positive cells in cyclopamine- (F), Ab5E1- (G), and forskolin-treated (H) animals relative to control (E). I and J, Least squares analysis of VVF versus Ki-67 (proliferative index) (I), and viable gland index (J), revealed an excellent correlation (R2 = 0.88 and 0.88, respectively; [P < 0.05]) among these groups.