Isotropic Anisotropic

ROLE OF DIFFUSION TENSOR IMAGING (DTI) IN INTRACRANIAL MASSES

Abstract Number: 117

AIM & OBJECTIVES

To obtain Fractional anisotropy & Mean diffusivity in various intracranial masses.

To assess the usefulness of tractography

DIFFUSION TENSOR IMAGING

The “diffusion tensor "is a matrix of numbers (mathematical model describing diffusion in 3D space) derived from diffusion measurements in several different directions (6+ directions for diffusion encoding).(1)

DIFFUSION

REVIEW OF LITERATURE•C.H.Toha, M.Castilloc et al. AJNR Am J Neuroradiology 2008 Mar ;29(3):471-5

•Primary cerebral lymphoma and glioblastoma multiforme: differences in diffusion characteristics evaluated with diffusion tensor imaging.

LYMPHOMA GLIOBLASTOMA

MULTIFORME

FA 0.140 ± 0.024 0.229 ± 0.069ADC (X10 ³mm²/s)ˉ 0.630 ± 0.155 0.963 ± 0.119

•Cut off values to differentiate lymphoma and glioblastoma multiforme were 0.192 for FA, 0.33 for FA ratio, 0.818 for ADC and 1.06 for ADC ratio.

MATERIALS & METHODS

FA & MD values were obtained &Tractography was performed.

Three region of interest cursors were placed in the lesion, perilesional area and the normal appearing white matter(NAWM) respectively.

20 Patients with intracranial masses ,proved histologically or by clinical follow up were subjected to DTI sequence.

Prospective study

DTI MR ACQUISITION

1.5T Scanner GE Signa HDxt or Seimens Avanto

Head And Neck Coil

Pulse sequence: Single Shot Echo Planar Imaging

Diffusion Directions: 25

Frequency and Phase Encoding: 128x128matrix

ROI: 2x2x2 mm³ b-value: 1000

Techniques : Conventional plain MR , Diffusion tensor imaging& Contrast MR.

GENDER

SEX

FEMALES-6

MALES-14

AGE DISTRIBUTION

10 to 20 20-30 30-40 40-50 50-600

1

2

3

4

5

6

7

8

Tumour

YEARS

NO

OF

PT.S

INTRACRANIAL MASSES DISTRIBUTION (n=20)

8

1

24

22 HIGH GRADE

GLIOMA

LOW GRADE GLIOMAS

MENINGIOMAS

SCHWANNO-MAS

DEMYELINA-TION

MEDULLOBLAS-TOMA

1

FA IN VARIOUS TUMORS

1 2 3 4 5 6 7 80

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

HIGH GRADE GLIOMALOW GRADE GLIOMADEMYELINATIONCONTROL

PATIENTS

FA

VALUE

FA IN VARIOUS TUMORS

1 2 3 40

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

MENINGIOMAMEDULLOBLASTOMASCHWANNOMACONTROL

PATIENTS

FA

VALUE

MD IN VARIOUS TUMORS

0 1 2 3 4 5 6 7 8 90

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

HIGH GRADE GLIOMASLOW GRADE GLIOMASDEMYLINATIONCONTROL

PATIENTS

MD

VALUE

MD IN VARIOUS TUMORS

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.50

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

CONTROLMENINGIOMASSCHWANNOMASMEDULLOBLASTOMAS

MD

VALUE

Patients

FA AND MD OF VARIOUS MASSESTUMORS FRACTIONAL ANISOTROPY MEAN DIFFUSIVITY

①(X10 ³mm²/s)ˉ

LESION PERILESIONAL AREA

NAWM⁺ LEISON PERILESIONAL AREA

NAWM⁺

HIGH GRADE GLIOMAS

0.135 0.254 0.312 1.260 1.143 0.774

LOW GRADE GLIOMAS

0.208 0.352 0.316 1.258 1.176 0.817

MEDULLOBLASTOMA

0.237 0.273 0.332 0.837 0.815 0.826

MENINGIOMAS

0.158 0.216 0.297 0.860 0.847 0.803

SCHWANNOMAS

0.162 0.233 0.331 1.352 1.224 0.805

DEMYELINATION

0.151 0.254 0.373 0.985 0.828 0.952

NAWM⁺:- NORMAL APPEARING WHITE MATTER

HIGH GRADE GLIOMA

T2 WEIGHTED TI POST CONTRAST

HIGH GRADE GLIOMA

FA IN THE LESION: 0.150CONTROL FA: 0.290

MD IN THE LESION:-1.120CONTROL MD:-0.730

HIGH GRADE GLIOMA

TRACTOGRAPHY

LOW GRADE GLIOMA

TI WEIGHTED T2 WEIGHTED

LOW GRADE GLIOMA

FA IN THE LESION:-0.146CONTROL FA:-0.413

MD IN THE LESION:-1.014CONTROL MD:-0.794

LOW GRADE GLIOMA

TRACTOGRAPHY

TRACTOGRAPHY

LOW GRADE GLIOMA

MEDULLOBLASTOMA

T2 WEIGHTED TI POST CONTRAST

MEDULLOBLASTOMA

FA IN THE LESION:-0.287CONTROL FA:-0.232

MD IN THE LESION:-1.014CONTROL MD:-0.782

MENINGIOMA

T2 WEIGHTED TI POST CONTRAST

MENINGIOMA

FA IN THE LESION:-0.101CONTROL FA:-0.297

MD IN THE LESION:-0.997CONTROL MD:-0.803

DISCUSSION

IN THIS STUDY STUDY BY LEE et alFA IN HIGH GRADE GLIOMAS

↓↓ ↓↓

FA IN LOW GRADE GLIOMAS

↓ ↓

Lee et al 2008 Mar-Apr;32(2):298-303. doi: 10.1097/RCT

Diffusion-tensor imaging for glioma grading at 3-T magnetic resonance imaging: analysis of fractional anisotropy and mean diffusivity.

DISCUSSIONFA IN PERILESIONAL AREA HIGH GR. GLIOMAS

FA IN PERILESIONAL AREA IN MENINGIOMA

MD IN PERILESIONAL AREA IN HIGH GR GLIOMA(10-3mm2/sec)

MD IN PERILESIONAL AREA IN MENINGIOMA(10-3mm2/sec)

IN THIS STUDY 0.254 0.216 1.143 1.176

STUDY BY PROVENZALE JM et al

0.178 0.224 1.309 1.427

Provenzale et al 2004 Aug;232(2):451-60. Epub 2004 Jun 23.

Peritumoral brain regions in gliomas and meningiomas: investigation with isotropic diffusion-weighted MR imaging and diffusion-tensor MR imaging.

DISCUSSIONFA-HIGH GR. GLIOMA

FA - TDLs MD - HIGH GR.GLIOMA

MD - TDLs

IN THIS STUDY

0.135 ↓↓ 0.151 ↓ 1.260 ↑↑ 0.985 ↑

STUDY BY C.H.TOHA et al

0.120 ↓↓ 0.180 ↓ 1.237 ↑↑ 0.887 ↑

C.H Toh AJNR Am J Neuroradiol 33:846 –51 May 2012

Differentiation of Tumefactive Demyelinating Lesions from High-Grade Gliomas with the Use of Diffusion Tensor Imaging

CONCLUSION

• Diffusion tensor imaging is a complimentary tool and an important adjunct to the conventional MRI.

• FA and MD values are useful in grading of intracranial mass lesions

• Tractography is useful to assess whether the white matter tracts are destroyed or displaced.

REFERENCES

*(₁)Diffusion Tensor Imaging of Cerebral White Matter: A Pictorial Review of Physics, Fiber Tract Anatomy, and Tumor Imaging Patterns by Brian J. Jellison et al. AJNR: 25, March 2004

*(2) Diffusion-tensor imaging for glioma grading at 3-T magnetic resonance imaging: analysis of fractional anisotropy and mean diffusivity. By Lee HY et al 2008 Mar-Apr;32(2):298-303.doi: 10.1097/RCT.

*(3)Peritumoral brain regions in gliomas and meningiomas: investigation with isotropic diffusion-weighted MR imaging and diffusion-tensor MR imaging. Provenzale JM et al 2004 Aug;232(2):451-60. Epub 2004 Jun 23.

*(4) Differentiation of Tumefactive Demyelinating Lesions from High-Grade Gliomas with the Use of Diffusion Tensor Imaging C.H.Toha et al december 15 , 2011,doi: 10.3174/ajnr.A2871.AJNR 2012 33/;846-851.