Dual-energy ct angiography for detection of pulmonary emboli: incremental benefit of iodine maps

Abstract

Purpose: To determine if there is an added benefit of using iodine maps from dual-energy (DECT) in addition to conventional CT angiography images to diagnose pulmonary embolism (PE).Materials and Methods: In this retrospective analysis, 49 consecutive dual-energy CT angiography examinations performed from August through July 2020 at Bach Mai Hospital to evaluate for PE were reviewed. The 49 examinations included 49 patients (mean age, 59.73 years; range, 22–99 years). First, the location, level, and type (occlusive vs nonocclusive) of PEs on conventional CT angiograms were recorded. Iodine maps were then reviewed for defects suggestive of PE. Last, CT angiograms were rereviewed to detect additional PEs suggested by the iodine map.Results: 19/49 (38.8%) patients were diagnosed with PE, a total of 247 PEs were detected at initial review. After review of the DECT iodine map, 16 additional PEs were found on 8 of 49 (16.3%) patients in which 2 of 49 (4 %) patients had a new diagnosis of PE after review of the DECT iodine maps, 4/49 (8%) patients were diagnosed PE before. Of the 16 additional PEs, 8 (50%) were segmental, 8 (50%) were subsegmental, 3 (18.8 %) were occlusive, and 13 (81.2%) were nonocclusiveConclusion: Dual-energy CT iodine maps show a small incremental benefit for the detection of occlusive segmental and subsegmental pulmonary emboli.