<prompt> Which one of the following is the investigation of choice for suspected deep vein thrombosis of the lower extremity ?Radioactive labelled fibrinogen uptakeAscending contrast phlebographyD-dimer estimationDuplex ultrasonography  <response>: Venous duplex ultrasonography is commonly performed to look for evidence of thromboembolism in superficial or deep venous system if lowe limbs. Reference:Bailey and love, 27th edition, page 988 