A systematic literature review of magnetic resonance spectroscopy for the characterization of brain tumors.
OBJECTIVE
Proton MR spectroscopy ((1)H-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 (1)H-MR spectroscopy. We abstracted information on study design, (1)H-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 (1)H-MR spectroscopy. Several studies have found that (1)H-MR spectroscopy is highly accurate for distinguishing high- and low-grade gliomas, though the incremental benefit of (1)H-MR spectroscopy in this setting is less clear. Interpretation for the other clinical subgroups is limited by the small number of studies.


CONCLUSIONS
The current evidence on the accuracy of (1)H-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.
Hollingworth
W
W
Department of Radiology, University of Washington, 325 Ninth Avenue, Seattle, WA 98104, USA. willh@u.washington.edu
Medina
L S
LS
Lenkinski
R E
RE
Shibata
D K
DK
Bernal
B
B
Zurakowski
D
D
Comstock
B
B
Jarvik
J G
JG
D001254:Astrocytoma / Q000175:diagnosis; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000556:secondary; D003937:Diagnosis, Differential; D005909:Glioblastoma / Q000175:diagnosis; D006801:Humans; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis
D006859:Hydrogen