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MR Spectroscopy Case Study
Astrocytoma - grade 2
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Prepared by Greg Brown    Royal Adelaide Hospital North Terrace Adelaide South Australia 5000
March 2nd 2001		 Back to MRS Page

Images and Spectra obtained on a Siemens VISION 1.5T using Numairs VB33E software.  Images and Spectra converted to JPEG files using eFilm.

Presentation Imaging MRS Technique MRS Results Histopathology Discussion

Presentation
 (HM) F49 Seizures for 2 years, increasing frequency recently becoming daily for the past 10 days.

Imaging
CT Right Frontal lobe mass with oedema
MRI
12/1/01		 FLAIR Axial Confirms large right frontal neoplasm of mixed signal with small areas of necrosis.  The lesion crosses to the left lobe via the corpus callosum.  there is patchy enhancement and adjacent oedema.  Spectroscopy was not reported on.

MRS Technique
SVS SE135 8cc voxel all within the tumour

MRS Results
Astrocytoma SVS SE135 spectrum MRS performed 15 minutes post contrast.  Shimming was good (9Hz) but peaks are broader than expected, probably due to Gadolinium.
Choline peak is very elevated and NAA is reduced.  The  inverted peak is probably Lactate with an adjacent noise signal.  
The MRS signs are those of a tumour with necrosis.

Integral Ratios
Cho Cr NAA Lactate Lipid Cho/Cr NAA/Cr NAA/Cho Cr/Cho
39.28 17.64 6.42 yes no 2.23 0.36 0.16 0.45
The curve fitting  probably overestimates NAA.       
 
 

Histopathology
Brain biopsy 15/1/01 of right frontal cortex and white matter, specimens were very small.
Sample 1: Well differentiated fibrous and gemistocytic Astrocytoma infiltrating the normal brain.
Sample 2: minute fragments of Astrocytoma, moderate nuclear pleonorphism but no mitosis in the specemin.   No tumour necrosis or vascular proliferation.
Diagnosis  Infiltrating Malignant Astrocytoma.  Tier grade 2:St. Anne-Mayo grade 2

Discussion
The spectrum agrees with Histopathology findings given the small sample of the lesion. the MRI appearances, specifically the crossing of the midline via the corpus callosum, were sufficient to identify the primary brain tumour.  MRS didn't really aid diagnosis and the patient was committed to biopsy on the MRI (or even the CT) findings anyway.