An apparatus and methods for diagnosing and treating nerve compression conditions in a patient, such as carpal tunnel syndrome, tarsal tunnel syndrome and other nerve compression conditions. Ultrasound transducer heads having an array of high frequency piezoelectric crystal elements mounted in the transducer head capable of delivering frequencies of 7.5 MHz or greater, and a low frequency piezocomposite element mounted in the transducer head capable of delivering frequencies of 0.25 MHz to 1.5 MHz at an intensity of about 0.25 W/cm.sup.2 to 2.0 W/cm.sup.2 can be used to diagnose and also treat the conditions. If necessary, the high frequency piezoelectric elements can be used to visualize the region of therapy to more accurately direct the low frequency ultrasound energy.