Value of 1H-magnetic resonance spectroscopy chemical shift imaging for detection of anaplastic foci in diffusely infiltrating gliomas with non-significant contrast-enhancement.
OBJECTIVE
In diffusely infiltrating gliomas (DIG), positron emission tomography (PET) imaging is a powerful method for detection of anaplastic foci. Recently, (1)H-magnetic resonance spectroscopy chemical shift imaging (CSI) using choline/creatine (Cho/Cr) or choline/N-acetylaspartate (Cho/NAA) ratios has emerged as a new non-invasive, widely available alternative. The authors therefore correlated CSI with (11)C-methionine (MET)-PET data in a series of DIG with non-significant contrast-enhancement (CE).


METHODS
Thirty-two patients with DIG were examined with single-slice CSI on a T MRI and MET-PET. Maximum pathological intratumoural ratios of CSI (=CSI(max)) and maximum tumour-to-normal-brain PET ratios (=PET(max); T/N ratio) were determined. Coregistration of MRI with CSI and PET was performed, and the topographic overlap of CSI(max) and PET(max) was analysed. Histological criteria of anaplasia as well as cell proliferation rate were assessed in tumour samples inside and outside CSI(max).


RESULTS
CSI showed a pathological ratio in all patients, whereas PET demonstrated a pathological T/N ratio in 21/32 patients. Topographical correlation of CSI(max) and PET(max) revealed a ≥ 50% overlap in 18/21 and <50% overlap in 3/21 patients, respectively. Cho/Cr(max) and Cho/NAA(max) showed a ≥ 50% overlap in 24/32 and a <50% overlap in 8/32 patients. Cell proliferation rate was significantly higher inside than outside the CSI(max) (13.6% vs 6.9%, p<0.001).


CONCLUSIONS
The results indicate that CSI is a promising method for detection of anaplastic foci within DIG with non-significant CE. Intraoperative use of CSI by multimodal neuronavigation may increase the reliability of detection of malignant areas in glioma surgery and therefore optimise allocation of patients to adjuvant treatments.
Widhalm
Georg
G
Department of Neurosurgery, Medical University Vienna, Vienna, Austria.
Krssak
Martin
M
Minchev
Georgi
G
Wöhrer
Adelheid
A
Traub-Weidinger
Tatjana
T
Czech
Thomas
T
Asenbaum
Susanne
S
Marosi
Christine
C
Knosp
Engelbert
E
Hainfellner
Johannes A
JA
Prayer
Daniela
D
Wolfsberger
Stefan
S
D000293:Adolescent; D000328:Adult; D000368:Aged; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001921:Brain / Q000378:metabolism / Q000473:pathology; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D005260:Female; D005910:Glioma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D055815:Young Adult
D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline