Trial Information

Two-Compartment Model of Diffusion Tensor Magnetic Resonance Imaging (DT-MRI) for the Diagnosis of Glioma Tumor Recurrence Versus Radiation Necrosis

The most common major side effect of radiation therapy for the treatment of primary brain
tumors is the necrosis of normal brain tissues (radiation necrosis). Radiation necrosis
typically occurs weeks to months following treatment. The diagnosis is suspected when
patients have new areas of gadolinium enhancement on magnetic resonance imaging (MRI) scans.
Tumor recurrence can also occur within weeks to months following treatment and is
represented by new areas of gadolinium enhancement as well. As the management options for
radiation necrosis and tumor recurrence are significantly different, distinguishing the two
is of critical importance. Conventional MRI, diffusion-weighted MRI (DW-MRI), MR
spectroscopy, SPECT, and PET imaging have all been used to try to make this distinction, but
the sensitivity and specificity of these techniques have not been clinically useful. Most
patients must therefore undergo a risky diagnostic surgical procedure. Diffusion tensor
MRI (DT-MRI) is an imaging technique that provides information regarding both the diffusive
properties of water as well as the directionality of water movement. A modification of
DT-MRI, referred to as two-compartment DT-MRI, appears to be more sensitive than other
variations of MRI for the diagnosis of selected types of brain abnormalities.

Objective: We plan to conduct a feasibility study to determine if two-compartment DT-MRI
can distinguish tumor recurrence from radiation necrosis.

Study Population: Patients aged greater than or equal to twenty one years old with a prior
diagnosis of primary brain tumor and history of radiation treatment who develop new areas of
gadolinium enhancement on conventional MRI scans and who require surgery for diagnostic or
therapeutic purposes will be evaluated for enrollment in this study. Ten patient controls
will also undergo DT-MRI scans for the purpose of obtaining normative data for this
quantitative study.

Design: Patients who meet eligibility criteria will undergo a two compartment DT-MRI scan.
Regions of abnormality will be identified and surgical biopsies will be obtained of these
regions. The radiographic and histologic characteristics of the samples will be correlated.
Volunteers will undergo DT-MRI scans only.

Outcome Measure: The primary outcome measure of this study is the degree of agreement
between the radiographically predicted diagnosis of tumor recurrence or radiation necrosis
using two-compartment DT-MRI and the histologic diagnosis of such. This outcome will be
measured as the proportion of instances in which the two modalities identify a particular
lesion as being tumor recurrence or as being radiation necrosis. The information gathered
from this study will allow for the implementation of a larger study with more patients if
there is a high degree of agreement between the two compartment DT-MRI and histologic
diagnoses of surgical biopsy specimens. The long range goal of the larger study is to
radiographically diagnose tumor recurrence or radiation necrosis with a high enough level of
sensitivity and specificity to avoid a diagnostic surgical procedure with its attendant
risks.