Three cases of pulmonary tumor thrombotic microangiopathy (PTTM): Challenge in antemortem diagnosis using lung perfusion blood volume images by dual-energy computed tomography.

Pulmonary tumor thrombotic microangiopathy (PTTM) is a specific type of tumor embolism in the small and medium pulmonary arteries, leading to rapid progressive pulmonary hypertension. Antemortem diagnosis of PTTM is extremely difficult. We encountered three patients who were histopathologically or clinically diagnosed with PTTM. In all cases, lung perfused blood volume (PBV) images on dual-energy computed tomography (CT) demonstrated multiple subpleural wedge-shaped defects with no evidence of pulmonary embolism on CT pulmonary angiography. The lung PBV images demonstrated small pulmonary arterial obstruction reflecting the pathology of PTTM. Therefore, lung PBV imaging would be useful for antemortem diagnosis of PTTM.