Abstract
BACKGROUND AND PURPOSE: Proton MR spectroscopy (1H-MR spectroscopy) is a potentially useful adjunct to anatomic MR imaging in the characterization of brain tumors. We performed an updated systematic review of the evidence.
METHODS: We employed a standardized search strategy to find studies published during 2002–2004. We reviewed studies measuring diagnostic accuracy and diagnostic, therapeutic, or health impact of 1H-MR spectroscopy. We abstracted information on study design, 1H-MR spectroscopy technique, and methodologic quality. We categorized studies into 5 subgroups: (1) metastasis versus high-grade tumor; (2) high-versus low-grade tumor; (3) recurrent tumor versus radiation necrosis; (4) tumor extent; and (5) tumor versus non-neoplastic lesion.
RESULTS: We identified 26 studies evaluating diagnostic performance, diagnostic impact, or therapeutic impact. No articles evaluated patient health or cost-effectiveness. Methodologic quality was mixed; most used histopathology as the reference standard but did not specify blinded interpretation of histopathology. One large study demonstrated a statistically significant increase in diagnostic accuracy for indeterminate brain lesions from 55%, based on MR imaging, to 71% after analysis of 1H-MR spectroscopy. Several studies have found that 1H-MR spectroscopy is highly accurate for distinguishing high- and low-grade gliomas, though the incremental benefit of 1H-MR spectroscopy in this setting is less clear. Interpretation for the other clinical subgroups is limited by the small number of studies.
CONCLUSION: The current evidence on the accuracy of 1H-MR spectroscopy in the characterization of brain tumors is promising. However, additional high-quality studies are needed to convince policy makers. We present guidelines to help focus future research in this area.
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