The diagnosis of bacterial overgrowth can be made by physicians in various ways. Malabsorption can be detected by a test called the D-xylose test. Xylose is a sugar that does not require enzymes to be digested. The D-xylose test involves having a patient drink a certain quantity of D-xylose, and measuring levels in the urine and blood ; if there is no evidence of D-xylose in the urine and blood , it suggests that the small bowel is not absorbing properly (as opposed to problems with enzymes required for digestion). 
The Gamma Knife Center at Columbia University Medical Center is outstanding, providing nonsurgical stereotactic radiosurgery for arteriovenous malformations . Patients requiring open surgical procedures will benefit from state-of-the-art facilities, a highly experienced operative team led by Dr. Solomon, and the finest neurosurgical intensive care facility in the country. Dr. Solomon was Chairman of the American Board of Neurological Surgery in 2007 and a past President of the New York State Neurosurgical Society , the Society of University Neurosurgeons, and the American Academy of Neurological Surgery .