Advances in the diagnostic imaging of pulmonary embolism (PE)

Learning Objectives 1. To illustrate the technological & interpretive advances made in diagnostic imaging for PE beginning from the era of CXR alone to the current times of lung scintigraphy and computed tomographic pulmonary angiography (CTPA)2. Review major landmark studies viz. PISAPED and PIOPED with a comparative analysis of their recommended interpretive criteria3. Comparative analysis of lung V/Q scintigraphy studies vs the CTPA4. Discuss the potential for V/Q SPECT in USA

Summary: This educational exhibit will review the evolution of different imaging modalities for the diagnosis of acute PE. We begin with planar lung Q scintigraphy, review the development of diagnostic systems that combine V scintigraphy and/or CXR with the Q scan, and discuss in detail the major landmark studies viz. Prospective Investigative Study of Acute Pulmonary Embolism Diagnosis (PISAPED) and the Prospective Investigation Of Pulmonary Embolism Diagnosis (PIOPED) series. Each of these studies recommends their own unique interpretive criteria; however, none of which are absolute sensitive or specific. The detailed discussion of these studies is aimed at enlightening the reader with the pros and cons of these individual studies with comparative analysis of the accuracies of their recommended interpretive criteria. This is followed with the discussion on the advent of CTPA and its emergence as the modality of choice for most patients with suspected PE. A comprehensive comparative analysis is made between the reported accuracies of CTPA and scintigraphy with review of PIOPED II and other similar studies in literature. Finally, we review the advances made with SPECT lung scintigraphy in the diagnosis of PE and its comparison with CTPA.