Lymphomas and glioblastomas: differences in the apparent diffusion coefficient evaluated with high b-value diffusion-weighted magnetic resonance imaging at 3T.
OBJECTIVE
As the usefulness of the apparent diffusion coefficient (ADC) obtained from diffusion-weighted images (DWI) for the differential diagnosis between glioblastoma and primary central nervous system lymphoma is controversial, we assessed whether high b-value DWI at b 4000 s/mm(2) could discriminate between glioblastoma and lymphoma. We also compared the power of high- and standard b-value (b-4000, b-1000) imaging on a 3-Tesla (3T) magnetic resonance (MR) instrument.


METHODS
This study was approved by our Institutional Review Board. We acquired DWI at 3T with b = 1000 and b = 4000 s/mm(2) in 10 patients with lymphoma and 14 patients with glioblastoma. The ADC was measured by placing multiple regions of interest (ROI) on ADC maps of the site of enhanced lesions on contrast-enhanced T1-weighted MR images. We avoided hemorrhagic and cystic lesions by using T1-, T2-, FLAIR-, and T2* MR images. The ADC values of each tumor were determined preoperatively from several ROI and expressed as the minimum-, mean-, and maximum ADC value (ADC(MIN), ADC(MEAN), ADC(MAX)). We evaluated the relationship between ADCs and histological information including tumor cellularity.


RESULTS
All ADC values were statistically associated with tumor cellularity. ADC(MIN) at b-4000 was associated with tumor cellularity more significantly than ADC(MIN) at b-1000. All ADC values were lower for lymphoma than glioblastoma and the statistical difference was larger at b = 4000- than b = 1000 s/mm(2). According to the results of discriminant analysis, the log likelihood was greatest for ADC(MIN) at b = 4000. At a cut-off value of ADC(MIN) = 0.500 × 10(-3)mm(2)/s at b-4000 it was possible to differentiate between lymphoma and glioblastoma (sensitivity 90.9%, specificity 91.7%).


CONCLUSIONS
Calculating the ADC value is useful for distinguishing lymphoma from glioblastoma. The lowest degree of overlapping and a better inverse correspondence with tumor cellularity were obtained with ADC(MIN) at b-4000 s/mm(2) at 3T MRI.
Department of Neurosurgery, Graduate School of Biomedical Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
Aidos
A
Doskaliyev
Fumiyuki
F
Yamasaki
Megu
M
Ohtaki
Yoshinori
Y
Kajiwara
Yukio
Y
Takeshima
Yosuke
Y
Watanabe
Takeshi
T
Takayasu
Vishwa Jeet
VJ
Amatya
Yuji
Y
Akiyama
Kazuhiko
K
Sugiyama
Kaoru
K
Kurisu
D000328:Adult; D000368:Aged; D000465:Algorithms; D001932:Brain Neoplasms / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005909:Glioblastoma / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008223:Lymphoma / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity