‘ Quick and Dirty’ 2D multi-voxel scans taken 1/25/07 – pre and post Gd.
3:18 with 2 NEX.
3x3cm voxels, 1cm thick.
Disease visible in voxel #2.
MRS: Normal vs. Disease Voxel # 7 - Normal Voxel # 2 - Disease
MRS: Pre vs. Post Gd Pre Gd Post Gd
Magnetic Resonance Spectroscopy
Although MRS has been shown to have discriminating power, there are two problems associated with it: 1) Low resolution. 2) Long scan time.
Imaging protocol will join MRS with RFSE DWMRI to create synergistic combination.
Arizona Biomedical Research Commission
Grant Awarded: Diffusion Weighted MRI and Magnetic Resonance Spectroscopy to Differentiate Radiation Necrosis and Recurrent Disease in Gilomas (PI LAE).
Enroll 60 patients diagnosed with a glioma (metastatic or primary) and follow longitudinally.
Patients eligible to enroll if they have a reasonable risk of suffering from RIN.
Published data indicate that patients receiving a dose of 60Gy in 30 Fx have between a 5 and 24% chance of developing RIN.
Hypo-fractionation and Stereotactic Radio-Surgery (SRS) are also forms of radiation Tx.
Imaging Protocol: Enrollment Criteria
Biological Equivalent Dose (BED) used to determine enrollment criteria for hypo-fractionation and SRS.
5 x 6Gy required for hypo - fractionation, 21Gy for SRS.
BED = nd(1 + ) with n the
number of fractions, d the dose, and the linear quadratic constants.
Imaging Protocol: Enrollment Criteria Radiation Type Number of Fractions Minimum Radiation (Gy) SRS 1 21 Hypo-fraction 5 30 Normal Fraction 30 60 Re-treatment varies varies
Imaging Protocol: Imaging Sequence Time from End of Radiotherapy (days) Scans Performed Comments -5 CT, MRI, DWMRI, MRS Baseline scans. Used to plan radiotherapy. CT and MRI registered using Brainscan. 30 MRI, DWMRI, MRS First scan for comparison. 90 MRI, DWMRI, MRS Second scan for comparison. Potential radiation necrosis. Check ADC W for change.
VOI centered at center of resection cavity.
2D Multi-voxel CSI with 1cm slice thickness. 7x7cm.
Three slices, ~8:30 for each slice, one centered on lesion and one superior and inferior.
MRS will take majority of time.
Current ‘Gold Standard’ for confirming glioma vs. RIN is pathologic examination of biopsy.
We expect that ~50% of enrolled patients will undergo biopsy at some point.
Vector Vision should locate biopsy location to within ~2mm.
Biopsy MRI registered with protocol MRI using Brainscan software.
Approved by SRC 11/14/06.
Third submission to IRB will take place early next week.
Expect approval shortly thereafter – 2/13/07
Patient enrollment thereafter.
DWMRI and MRS are non-invasive forms of medical imaging that show promise for differentiation between RIN and recurrent disease in glioma patients.
It will take work to realize the full potential of these complimentary imaging forms.