1. College of Medicine, Qassim University, Qassim,
2. College of Medicine, King Saud bin Abdulaziz University for Health Sciences,
3. King Abdullah International Medical Research Center,
4. Division of Neurosurgery, Department of Surgery, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs,
5. Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs, Riyadh, Saudi Arabia.