The "injection jet sign": an innovative method of needle position confirmation during ultrasound guided injections

Ultrasound (US)-guided therapeutic and diagnostic injections play an important role in day-to-day clinical practice for many radiologists. When compared with fluoroscopic or computed tomographic (CT) methods of localization, US offers the benefit of real-time confirmation of instrument position without exposing the patient to any ionizing radiation. Target delivery is usually confirmed by direct needle tip visualization and with real-time demonstration of capsular or bursal distention. While often more technically difficult in deeper anatomic spaces, larger patients and smaller delivery needles, US should still be considered the preferred method of image guidance because of these outlined benefits. We present here three cases demonstrating an innovative method of needle-tip position confirmation, termed the "injection jet sign." This technique represents a useful supplement to routine sonographic guidance and allows the clinician to enjoy the benefits of this imaging modality even in the face of other technical challenges.