1. Division of Respiratory Medicine, Mito Medical Center, University of Tsukuba, Mito, Ibaraki 3100015, Japan
2. Division of Neurology, Mito Medical Center, University of Tsukuba, Mito, Ibaraki 3100015, Japan
3. Division of Thoracic Surgery, Mito Medical Center, University of Tsukuba, Mito, Ibaraki 3100015, Japan
4. Division of Thoracic Surgery, Ibaraki Medical Center, Tokyo Medical University, Ami, Ibaraki 3000395, Japan