Comparison of PET and Proton MRS Imaging to Evaluate Pediatric Brain Tumor Activity
Condition: Brain Tumors
MeSH terms: Brain Neoplasms
Study type: Observational

Summary: 
      This study in children and young adults will compare two types of imaging, positron emission
      tomography ([(18)F]-DG PET) and proton magnetic resonance spectroscopy ((1)H-MRSI), to
      determine activity of a brain tumor or abnormal tissue in the brain following treatment for a
      brain tumor. Children with brain tumors are generally followed with magnetic resonance
      imaging (MRI) scans to evaluate response to treatment. However, because MRI only provides
      information on the structure of the brain, it may difficult to tell if an abnormal finding is
      due to tumor, swelling, scar tissue, or dead tissue. (1)H-MRSI and [(18)F]-DG PET, on the
      other hand, provide information on the metabolic activity of brain lesions. These two methods
      will be compared and evaluated for their ability to provide important additional information
      on childhood brain tumors.

      Patients between 1 and 21 years of age with a brain tumor or brain tissue abnormality
      following treatment for a brain tumor may be eligible for this study. Candidates will be
      screened with a medical history and physical examination, pregnancy test in women who are
      able to become pregnant, and a blood test for glucose.

      Participants will undergo the following procedures:

      (1)H-MRSI - This test is similar to MRI and is done in the same scanning machine. In MRI,
      scans of the brain are obtained by applying a strong magnetic field and then collecting the
      signals released from water after the magnetic field is changed. Pictures of the brain are
      then obtained by computer analysis of these signals. In (1)H-MRSI, the computer blocks the
      signal from water to get information on brain chemicals that can indicate whether an
      abnormality is tumor or dead tissue. Both MRI and MRI and (1)H-MRSI are done in this study.

      For these tests, the child lies on a stretcher that moves into the scanner - a narrow metal
      cylinder with a strong magnetic field. The child's head is placed in a headrest to prevent
      movement during the scan. He or she will hear loud thumping noises caused by the electrical
      switching of the magnetic field. A contrast agent is given through an intravenous (IV)
      catheter (plastic tube placed in an arm vein) or through a central line if one is in place.
      The contrast material brightens the images to provide a clearer picture of abnormalities.
      Children who have difficulty holding still or being in a scanning machine are given
      medications by an anesthesiologist to make them sleep through the procedure. Children who are
      awake during the procedure can communicate with the MRI technician at all times and ask to be
      removed from the scanner at any time. The MRI and (1)H-MRSI take 1-1/2 to 2 hours to
      complete.

      [(18)F]-DG PET - For this test, [(18)F]-DG (a radioactive form of glucose) is injected into
      the patient's arm vein through a catheter, followed by the PET scan, similar to a very open
      MRI scan without the noise. The PET scan tells how active the patient's tumor is by tracking
      the radioactive glucose. All cells use glucose, but cells with increased metabolism, such as
      cancer cells, use more glucose than normal cells. After the glucose injection, the patient
      lies quietly in a darkened room for 30 minutes, after which he or she is asked to urinate to
      help reduce the dose of radiation to the bladder. Then, the scan begins. When the scan is
      finished (after about 1 hour), the child is asked to urinate again and then every 3 to 4
      hours for the rest of the day.

      Patients remain in the study for 2 years unless they withdraw, become pregnant, or require
      sedation but can no longer use an anesthetic. MRI and 1H-MRSI scans may be repeated every few
      months during the study period, if necessary. Only one PET scan is done each year.
    

Detailed description: 
      Background:

        -  Children with brain tumors are generally followed for response or progression by imaging
           studies, such as CT or MRI.

        -  While these imaging studies help delineate the anatomical location and extent of a tumor
           within the CNS, they give no information regarding the biologic or metabolic activity of
           the lesion.

        -  Proton Nuclear Magnetic Resonance Spectroscopic Imaging ((1)H-MRSI) is a non-invasive
           method of detecting and measuring cellular metabolites in vivo, providing biochemical
           information in conjunction with the spatial information obtained by MRI.

        -  Positron Emission Tomography (PET) is a technique that also provides data on metabolic
           activity of brain lesions.

        -  A comparison of these two methods in determining a lesion s metabolic activity has not
           been reported in children with brain tumors.

      Objective:

      -To compare (1)H-MRSI and [(18)F-]-FDG PET scanning percentage (%) of agreement between
      supratentorial and infratentorial tumors, and between brainstem and cerebellum intratentorial
      tumors.

      Eligibility:

        -  Age: greater than or equal to 1 year and less than to 21 years

        -  Patients must have a brain tumor that is measurable or evaluable on standard MRI or CT.

      Design:

        -  Patients referred for this study will have both (1)H-MRSI and (18)F-FDG PET imaging
           performed within 2 weeks of each other at the NCI

        -  Patients will remain on study for 5 years or until one of the off-study criteria have
           been met (whichever occurs first)
    

Intervention name(s): 2-Flourodeoxyglucose
Intervention type(s): Drug
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients must have a brain tumor (including, but not limited to high grade gliomas,
        low-grade gliomas, primitive neuroectodermal tumors, ependymomas) or residual abnormality
        (e.g. post-operatively or post-radiation) that is measurable or evaluable on standard MRI
        or CT
      
Keywords: Brain Tumor; Children; Metabolic; Spectroscopy; PET; Natural History