A displaced Cu T using plain xray pelvis and uterine sound?

How can we know the location of a displaced Cu T using plain xray pelvis and uterine sound?

A plain X-ray or pelvic ultrasound is used in the localization of the IUCD when the IUCD threads cannot be visualized. In this patient, the misplaced IUCD is seen laterally displaced in the pelvic cavity. An abnormal location or abnormal shape of IUCD indicates likely perforation of the uterus.

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