The imaging implications of implementing the BTS guidelines for management of acute PE

Abstract

The BTS has recently published new guidelines for the investigation of suspected pulmonary embolus (PE). The management pathway requires a reliable assessment with all patients of low or intermediate clinical probability having a D-dimer assay. If the D-dimer is negative, no further investigation for PE is recommended. For patients with a high clinical probability or a positive D-dimer assay, imaging is recommended with a preference for CTPA, particularly if the CXR is abnormal. We performed a retrospective review of the 859 V/Q studies over a 12 month period from August 2002 to July 2003 to evaluate the clinical outcome of the patient's study and to determine whether other imaging was performed. Seventeen per cent of these studies had an abnormal CXR. Overall, 41.8% of the studies were normal, with the following probabilities for acute PE: low 37.6%, intermediate 5.6%, and high 15%. Further imaging was performed in 96 patients (11.1%), 22 patients with an intermediate V/Q scan had a CTPA with 9 being positive and 15 negative. Given that the radiation and financial burden of V/Q and CTPA are 1.2 mSv and £380 vs 4.2 mSv and £120, respectively, we conclude that it is justifiable to use the V/Q as the gatekeeper in PE imaging reserving CTPA for intermediate V/Q results.