Objective: A trial was conducted to establish the added diagnostic value of an automated proton MR spectroscopy (MRS) examination (PROBE).
Materials and methods: The PROBE and MRS were compared for metabolite ratios of normal controls and 21 patients. In addition, PROBE was performed in either the occipital cortex (gray matter) or the parietal cortex (white matter) or, more rarely, within the confines of a focal lesion identified on MRI, using a GE Signa 1.5 T whole-body scanner, in 112 patients undergoing routine brain MRI. The trial was conducted in three different MR centers to establish percentage of positive findings with MRI vs. MRI plus MRS.
Results: Cerebral metabolite ratios (N-acetylaspartate/creatine, choline/creatine, myo-inositol/creatine) obtained by PROBE and MRS were similar. Metabolite profiles in dementia, head trauma, herpes encephalitis, hepatic and hypoxic encephalopathy, stroke, and tumor were identified using PROBE. The PROBE technique increased the number of positive findings ("added value") achieved by MRI; the added value was 28, 21, and 93% for the three trial sites.
Conclusion: With only minor variations, PROBE reproduces the cerebral metabolite patterns obtained with MRS. It significantly increases the diagnostic yield of routine neuroimaging and might be incorporated as a standard sequence in a cost-effective manner.