title: Can diffusion tensor metrics help in preoperative grading of diffusely infiltrating astrocytomas? A retrospective study of 36 cases.
abstract: 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.
authors.affiliation: Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India.
authors.forename: Milan
authors.initials: M
authors.lastname: Jolapara
authors.forename: Satya Narayan
authors.initials: SN
authors.lastname: Patro
authors.forename: Chandrasekharan
authors.initials: C
authors.lastname: Kesavadas
authors.forename: Jitender
authors.initials: J
authors.lastname: Saini
authors.forename: Bejoy
authors.initials: B
authors.lastname: Thomas
authors.forename: Arun Kumar
authors.initials: AK
authors.lastname: Gupta
authors.forename: Narendra
authors.initials: N
authors.lastname: Bodhey
authors.forename: Vishnupuri Venkatraman
authors.initials: VV
authors.lastname: Radhakrishnan
mesh_terms: 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
references.citation: AJNR Am J Neuroradiol. 2004 May;25(5):746-55
references.pmid: 15140713
references.citation: J Magn Reson Imaging. 2001 Apr;13(4):534-46
references.pmid: 11276097
references.citation: Neuroradiology. 1992;34(6):463-9
references.pmid: 1436452
references.citation: AJNR Am J Neuroradiol. 2000 Apr;21(4):659-65
references.pmid: 10782774
references.citation: Acta Neuropathol. 2007 Aug;114(2):97-109
references.pmid: 17618441
references.citation: AJNR Am J Neuroradiol. 2001 Jun-Jul;22(6):1081-8
references.pmid: 11415902
references.citation: Radiographics. 2006 Oct;26 Suppl 1:S205-23
references.pmid: 17050517
references.citation: J Magn Reson Imaging. 1999 Jan;9(1):53-60
references.pmid: 10030650
references.citation: Surg Neurol. 2005 Jan;63(1):56-61; discussion 61
references.pmid: 15639528
references.citation: J Magn Reson. 1999 Nov;141(1):68-77
references.pmid: 10527745
references.citation: J Neurooncol. 2003 Jun;63(2):109-16
references.pmid: 12825815
references.citation: J Neurosurg. 1993 Oct;79(4):533-6
references.pmid: 8410222
references.citation: Radiology. 1990 Feb;174(2):411-5
references.pmid: 2153310
references.citation: AJNR Am J Neuroradiol. 2000 Oct;21(9):1645-9
references.pmid: 11039343
references.citation: Magn Reson Med. 2006 Jan;55(1):136-46
references.pmid: 16342267
references.citation: AJNR Am J Neuroradiol. 2008 Oct;29(9):1630-5
references.pmid: 18583409
references.citation: Neuroradiology. 2000 May;42(5):333-8
references.pmid: 10872152
references.citation: J Magn Reson B. 1996 Jun;111(3):209-19
references.pmid: 8661285
references.citation: Clin Neurol Neurosurg. 2005 Apr;107(3):174-80
references.pmid: 15823671
references.citation: Neuroradiology. 2004 May;46(5):339-50
references.pmid: 15103435
references.citation: AJNR Am J Neuroradiol. 2001 Jan;22(1):60-4
references.pmid: 11158889
references.citation: Neurol Res. 1996 Aug;18(4):321-4
references.pmid: 8875449
references.citation: Brain Res. 1998 Jan 5;780(1):27-33
references.pmid: 9473573
references.citation: AJNR Am J Neuroradiol. 2002 Apr;23(4):520-7
references.pmid: 11950638
references.citation: AJNR Am J Neuroradiol. 2006 Aug;27(7):1412-8
references.pmid: 16908549
references.citation: Neuroradiology. 2009 Feb;51(2):123-9
references.pmid: 18839162
references.citation: N Engl J Med. 1991 May 23;324(21):1471-6
references.pmid: 1822669
references.citation: AJNR Am J Neuroradiol. 2003 Nov-Dec;24(10):1989-98
references.pmid: 14625221
references.citation: Neuroimaging Clin N Am. 2006 Nov;16(4):619-32, viii-ix
references.pmid: 17148023