CPT code 97035, ultrasound, is defined as a constant-attendance modality wherein there is direct, one-on-one contact by the provider during the delivery of the service. Because of its constant-attendance requirement, 97035 is billable in units based on each 15 minutes of application. (For information on billing units and the specific time requirements, please see "Billing Units of Service: The Element of Time" in the April 23, 2007 issue of Dynamic Chiropractic).
Because of the constant-attendance requirement, it would not be
appropriate to bill this type of ultrasound service under the 97035 code
since the code requires that the provider remain in contact with the
patient throughout the entire procedure. This constant contact is, of
course, a requirement for standard ultrasound due the sound head being
hand-held and needing continuous motion during application of the
therapy.