New opacities in lung allograft after transbronchial cryobiopsy.

Background: The occurrence of radiological opacities post-transbronchial cryobiopsy may pose serious difficulties in differential diagnosis and management of lung allografts. This prospective study evaluated the frequency, characteristics, and evolution of new lung opacities after performing transbronchial cryobiopsy.

Methods: From February 2018 to June 2018, 22 of 51 consecutive patients with an indication for transbronchial cryobiopsy underwent computed tomography (CT) of the thorax before and at 1, 4, and 8 weeks post-cryobiopsy. New CT images, required by the transplant team, were also evaluated during the next 6 months. Histological findings of transbronchial cryobiopsy and microbiological studies on bronchoalveolar lavage were evaluated as risk factors for opacities.

Results: After obtaining 112 cryobiopsy samples, 46 opacities >10 mm, including ground-glass, solid, cavitated, or a combination of these lesions were observed in 20 (91%) patients on post-cryobiopsy CT. All ground-glasses opacities on CT disappeared at 4 weeks. A single cavitated opacity persisted at 6 months. The remaining opacities disappeared or were decreased to <10 mm by 8 weeks. No correlations of the number, type, or evolution of opacities with the number or volume of cryobiopsy samples obtained, or with the histological diagnosis, type of transplant, or microbiologic culture results were observed.

Conclusion: New pulmonary opacities >10 mm occur frequently after transbronchial cryobiopsy; a few may persist beyond 6 months. CT studies are recommended before implementing transbronchial cryobiopsy, whenever possible.