Ferumoxytol- and Gadolinium-Labeled MRI in Measuring Tumors Before or After Treatment in Patients With Primary or Metastatic Brain Tumors

• CNR, in terms of normalized signal intensity changes, for DSC MRI data sets at 3T and 7T (ferumoxytol only) [ Time Frame: Day 2 to day 3 ]
  Paired sample t-tests will be used for primary descriptive comparisons. Secondary analyses will use a repeated measures ANOVA model to compare 3T and 7T while adjusting for other factors including tumor type, prior therapy, and, potentially, important baseline factors that differ between the subjects assigned to the two field strengths. Normality will be assessed graphically and, if needed, a transformation (e.g. the logarithmic transform) will be applied.
  
  
• CNR, in terms of normalized signal intensity changes, for T1-weighted MRI signal at 3T and 7T (Gd T1-weighted MRI data only) [ Time Frame: Baseline to day 1 ]
  Paired sample t-tests will be used for primary descriptive comparisons. Secondary analyses will use a repeated measures analysis of variance (ANOVA) model to compare 3T and 7T while adjusting for other factors including tumor type, prior therapy, and, potentially, important baseline factors that differ between the subjects assigned to the two field strengths. Normality will be assessed graphically and, if needed, a transformation (e.g. the logarithmic transform) will be applied.
  
  

• Change in CBV measurements, quantified using DSC techniques [ Time Frame: Day 1 to day 2 ]
  Blood volumes will be compared using repeated measures ANOVA to compare the imaging agents.
  
  
• Change in tumor microvascularity on SWI before and after ferumoxytol [ Time Frame: Day 2 to day 3 ]
  Analysis will also include covariates of prior therapy. For the comparisons between treated and untreated subjects, means and confidence intervals will be estimated for each group for the perfusion and permeability measures and for the baseline characteristics.
  
  
• Presence of iron staining [ Time Frame: At time of surgery ]
  The pathology will be analyzed qualitatively for the presence of iron staining. The amount and localization of the staining will be assessed, with attention paid to whether the tumor cells themselves or reactive cells in and around the tumor demonstrate iron uptake.
  
  
• Relevant dynamic MRI (DCE and DSC) signal intensity changes for permeability and perfusion [ Time Frame: Day 1 to day 2 ]
  Mixed model repeated measures ANOVAs will be fit. Factors will include imaging agent (Gd or ferumoxytol) and field strength (3T and 7T). Each subject will contribute one measure for each combination of imaging agent and field strength (4 measures total).
  
  

PRIMARY OBJECTIVES:

I. To compare quantitative blood brain barrier permeability measurements (derived transfer coefficient [Ktrans]) of a standard gadolinium (Gd) MRI contrast agent at 3T and 7T using dynamic contrast enhancement (DCE) MRI.

II. To compare dynamic susceptibility contrast (DSC) based perfusion measures at 3T and 7T.

SECONDARY OBJECTIVES:

I. To describe the blood brain barrier permeability to ferumoxytol (ferumoxytol non-stoichiometric magnetite) and to a standard gadolinium-based MRI contrast agent using signal intensity changes as described above.

II. To describe cerebral blood volume (CBV) measurements obtained using a standard gadolinium MRI contrast agent and ferumoxytol.

III. To evaluate tumor microvascularity on susceptibility-weighted images (SWI).

IV. To describe the microscopic distribution of ferumoxytol particles in tissue removed from subjects undergoing surgery.

OUTLINE: Patients are assigned to 3T or 7T magnet within the subgroups.

Patients receive gadolinium intravenously (IV) on day 1 and ferumoxytol non-stoichiometric magnetite IV on day 2. Patients undergo anatomical MRI sequences with 3T or 7T at baseline and on days 1-3. Patients also undergo DSC MRI and DCE MRI on days 1-2. Day 1 and day 2 imaging sessions may be separated by up to 7 days.

After completion of study, patients are followed up at approximately 4-6 weeks.