A 54 year old patient 7 days after a total hip replacement presents with acute onset breathlessness and raised JVP. Which of the following investigation will be most helpful in leading to a diagnosis?

The key is B. CTPA. [The patient has a +ve two level PE Wells score (if it was negative we should do

D-Dimer) and there is no renal impairment or history suggestive of allergy to contrast media (if these

were present we should have gone for VQ scan) the investigation of choice is PTCA. NICE guideline].