Organized thrombus in pulmonary arteries in patients with chronic thromboembolic pulmonary hypertension; imaging with cone beam computed tomography.

PURPOSE: To assess the usefulness of cone-beam CT (CBCT) during pulmonary angiography for the evaluation of organized thrombus at segmental or subsegmental arteries in patients with chronic thromboembolic pulmonary hypertension (CTEPH).

MATERIALS AND METHODS: The segmental and/or subsegmental pulmonary arteries of 13 patients with CTEPH were evaluated by CBCT. We classified representative forms of organized thrombus into 4 types (type 1: webs, type 2: web and slits, type 3: slits, and type 4: narrowing or complete occlusion), and the distribution and frequency of the organized thrombus were evaluated. The relative detectability of these lesions using CBCT was compared with that in contrast-enhanced CT pulmonary angiography (CTPA).

RESULTS: Type 1 lesions were most frequently observed in both segmental (30/65 = 46 %) and subsegmental branches (72/156 = 46 %). Type 2 lesions were relatively less frequent than type 1, but subsegmental branches were frequently involved (29/156 = 19 %). Type 3 lesions observed as a thin flap in 9/156 subsegmental branches (6 %). Comparing with CTPA, all 40 lesions in segmental branches were detectable in CTPA, whereas only 62 lesions among 90 lesions (69 %) in subsegmental branches could be observed by CTPA.

CONCLUSION: CBCT is found to be useful for the treatment planning of balloon pulmonary angioplasty distal to segmental arteries.