Proton MRS imaging in the follow-up of patients with suspected low-grade gliomas

We compared the value of changes in proton magnetic resonance spectroscopic imaging (1H-MRSI) with changes in clinical status and/or contrast-enhanced magnetic resonance imaging (MRI) in the monitoring of patients with suspected low-grade glioma (LGG). From June 1, 1999 till May 31, 2002, we included consecutive, neurologically intact adult patients suspected of having an LGG, demonstrating non-enhancing supratentorial lesions without edema or mass effect on MRI, and in whom all treatment (including a diagnostic biopsy) was deferred. Till January 1, 2003, patients were surveyed clinically and radiologically (contrast-enhanced MRI and 1H-MRSI). Patients who showed progression on clinical examination and/or MRI were denoted as progressive disease. Other patients were denoted as stable disease. A decrease in NAA/CHO ratio of ≥20% compared to the baseline value was considered as indicative for progression on 1H-MRSI. We included 14 patients with suspected LGG. Seven patients demonstrated progressive disease during the follow-up period, preceded or accompanied by concomitant 1H-MRSI changes in five patients. Four of these five patients were operated on within the follow-up interval. The histological diagnosis demonstrated high-grade glioma in three and LGG in one patient. (orig.)