An ultrasonic diagnostic imaging system with a two dimensional array transducer performs microbubble-mediated therapy such as sonothrombolysis. The array is formed by dicing into rectilinear elements with the corner elements absent to provide a generally rounded shape that accommodates the temporal windows of the head for cranial therapeutic energy delivery. In several described implementations additional transducer elements are optimized for other specialized functions such as A-line imaging, Doppler flow detection, temporal bone thickness estimation, or cavitation detection. Preferably there are 128 therapeutic elements so that the array probe can be used with standard ultrasound systems having 128-channel beamformers.