The target sign - also called the doughnut sign - is the ultrasound finding that identifies intussusception on point-of-care ultrasonography. When one segment of the bowel telescopes into an adjacent segment, as occurs in intussusception, scanning across the affected area in the transverse plane produces a characteristic appearance of concentric rings: the outer wall of the receiving bowel, the mesenteric fat and wall of the intussuscepted segment, and further inner rings from the layers of telescoped bowel. The result on the ultrasound screen is a circular pattern of alternating echogenicities - dark and bright rings - that resembles a target or cross-section of a doughnut. This sign has high sensitivity and specificity for intussusception when it is identified by a trained examiner - in other words, when it is present, it is almost always intussusception, and when intussusception is present, it is almost always visible on POCUS in experienced hands. The clinical importance is that this finding is available immediately, at the bedside, in the emergency department, without the child needing to be moved to a radiology department, without radiation exposure, and without waiting for a formal ultrasound request and report. At Vatsalya Children's Hospital, Varanasi, when I identify the target sign on bedside POCUS in an infant with episodic colicky pain, the management pathway begins at that moment - surgical referral and preparation for therapeutic enema reduction, rather than hours of observation while waiting for formal imaging.
Written by Dr. Chhaya Pathak, MBBS, MD (Pediatrics), Senior Consultant Paediatrician, Neonatologist and Intensivist, Pioneer of Paediatric POCUS in Eastern Uttar Pradesh, Co-Founder, Vatsalya Children's Hospital, Mahavir Road, Orderly Bazar, Varanasi, Uttar Pradesh 221002. 40+ years, 1,00,000+ patients. Phone: +91 9838585111.
