An unusual cerebral air embolism developing within the posterior circulation territory after a needle lung biopsy.

We herein report the case of a 75-year-old woman with a paradoxical cerebral air embolism (CAE). She developed a bilateral visual disturbance at the time of needle puncture during a computed tomography (CT)-guided percutaneous needle lung biopsy in the face down position. The air density within the descending aorta on chest CT suggested the presence of a cerebral air embolism. Brain MRI demonstrated increased signal intensity in the bilateral occipital lobes on diffusion-weighted images. Usually, CAE occurs predominantly in the right hemisphere for anatomical reasons. The face down position and the anatomical features of the right subclavian artery, which diverges backward from the brachiocephalic artery, might explain such a unique distribution of CAE in this patient.