1. Department of Neurosurgery, Daqing Oil Field General Hospital, Daqing, Heilongjiang 163001, P.R. China
2. Department of Gastroenterology, The Fourth Hospital of Daqing, Daqing, Heilongjiang 163001, P.R. China
3. Department of The Heart of Non‑Invasive Examination, Daqing Oil Field General Hospital, Daqing, Heilongjiang 163001, P.R. China
4. Department of Neurosurgery, Harbin Medical University Cancer Hospital, Harbin, Heilongjiang 150001, P.R. China