Evaluation of Radiation-Induced Vasculopathy by Transcranial Doppler (TCD) Among Survivors of Childhood Medulloblastoma Treated with Cranial Radiation Therapy
Participation in the study should require a single visit. All study-related procedures and tests will be performed during the single visit. The study visit should take less than 4 hours. Upon signing informed consent, patients will be evaluated with the following examinations: (1) History and physical examination, including blood pressure, weight:hip ratio. (2) Transcranial doppler examination to measure carotid artery blood flow velocity: Commercially available Transcranial Doppler machines will be utilized for this study. At our institution, the EME Pioneer TC 4040 is used for TCD studies. Vessel insonation will be performed according to the standard protocol used by the UT Southwestern Medical School Neuro-sonology Laboratory for routine examinations. This protocol utilizes Transtemporal, Transorbital and Sub-Occipital approaches. Review of TCD studies will be performed by Dr. Mark Johnson at the UT Southwestern Medical School in Dallas. Criteria to be used in the identification of intracranial occlusive disease will be based on criteria from Alexandrov and Neumyer in the chapter Diagnostic Criteria for Cerebrovascular Ultrasound from the book Cerebrovascular Ultrasound in Stroke Prevention and Treatment. (3) Blood will be obtained to determine serum cholesterol, HDL-cholesterol, LDL-cholesterol, apolipoprotein A, apolipoprotein B, hemoglobin A1C, and CRP. Also, patients[Right Quote] medical records will be examined for a pre-existing diagnosis of growth hormone deficiency (alternatively, patients can be screened with an IGF-1 and IGFPB-3). (4) 12 Lead EKG.
1. Survivors of brain tumors during childhood (age < 18 years at diagnosis).
2. Patients who are > 3 years after their cancer treatment (It is anticipated that most patients will be between the ages of 10 – 25 years old).
3. Prior treatment with > 20 Gy cranial RT to the hypothalamus and (by default) the Circle of Willis.
4. No history of anemia, congestive heart failure, or hyperthyroidism (Hyperthyroidism is associated with false positive blood flow velocities by TCD).
5. No prior history of stroke or transient ischemic attacks (TIAs).