Can diffusion tensor metrics help in preoperative grading of diffusely infiltrating astrocytomas? A retrospective study of 36 cases.
BACKGROUND
Diffusion weighted imaging and diffusion tensor imaging (DTI) give information about the amount and directionality of water diffusion occurring in a given tissue. Here we study the role of diffusion tensor metrics including fractional anisotropy (FA) and spherical anisotropy (CS) in preoperative grading of diffusely infiltrating astrocytomas.


METHODS
We performed DTI in 38 patients with pathologically proven diffusely infiltrating astrocytomas, who were classified into two groups, i.e., 15 patients with high-grade astrocytoma (HGAs, WHO grade III and IV) and 23 patients with low-grade astrocytoma (LGAs, WHO grade II). We measured maximum FA and minimum CS values in all cases from tumor. Histopathological diagnosis was established in all cases.


RESULTS
The mean maximum FA values were higher in HGA (0.583 ± 0.104) than LGA (0.295 ± 0.058), while mean minimum CS values were lower in HGA (0.42 ± 0.121) than LGA (0.722 ± 0.061). The difference in the diffusion tensor indices between HGA and LGA was found to be statistically significant with P value of <0.001. Keeping cutoff FA value of 0.4, all HGAs showed higher maximum FA values, and all LGAs showed lower maximum FA values. Also, all HGAs showed minimum CS values less than a cutoff value of 0.6, and all LGAs showed minimum CS values higher than 0.6.


CONCLUSIONS
Diffusion tensor metrics such as maximum FA and minimum CS can help to differentiate HGA from LGA.
Jolapara
Milan
M
Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India.
Patro
Satya Narayan
SN
Kesavadas
Chandrasekharan
C
Saini
Jitender
J
Thomas
Bejoy
B
Gupta
Arun Kumar
AK
Bodhey
Narendra
N
Radhakrishnan
Vishnupuri Venkatraman
VV
D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000473:pathology*; D001932:Brain Neoplasms / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D015588:Observer Variation; D011300:Preoperative Care / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult
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