Ultrasonic needle localization

An ultrasound system comprising:

• an ultrasound scanner having a multi-array transducer configured to transmit first ultrasound at a patient anatomy, receive reflections of the first ultrasound from the patient anatomy, and receive additional ultrasound from at least one ultrasound transducer element, wherein the multi-array transducer is configured to generate interleaved variable-width elevational planes simultaneously using a different array to transmit a different one of the interleaved variable-width elevational planes;
• an interventional instrument having the at least one ultrasound transducer element attached to the interventional instrument and configured for insertion towards the patient anatomy as part of an insertion procedure;
• a processor system configured to:
• determine, during the insertion procedure, an occurrence of a trigger event, wherein the interventional instrument has crossing the first ultrasound of at least one of the elevational planes of one or more outer arrays of the multi-array transducer;
• instruct, responsive to the determination of the occurrence of the trigger event, the at least one ultrasound transducer element to transmit the additional ultrasound;
• and
• determine, based on the reception of the additional ultrasound by the ultrasound scanner, that the interventional instrument is detected;
• and
• a display device configured to display an ultrasound image of the patient anatomy based on the reflections of the first ultrasound and a visual representation that indicates the detection of the interventional instrument.