Neurological Surgery 脳神経外科39巻10号

2011年10月発行

総説

MRI拡散テンソル画像：最近の進歩

著者： 青木茂樹¹ 福永一星² 堀正明¹

所属機関： ¹順天堂大学医学部放射線医学講座 ²首都大学東京人間健康科学研究科放射線学域

ページ範囲：P.935 - P.946

Ⅰ．拡散テンソル画像法とは

　拡散テンソル画像（diffusion tensor imaging：DTI）は，拡散強調像の応用として1994年にBasserらにより提唱された方法⁶⁾で，各画素（voxel）の水の拡散を3×3の対称行列で表す方法である．対角化により楕円体（ellipsoid）の3つの主軸（e1，e2，e3）とそのベクトルの方向の拡散係数となる3つの固有値（λ1≧λ2≧λ3≧0）で表される．白質では線維の方向に楕円体の長軸が向き，白質の方向とe1の方向が一致し，白質の方向の見かけの拡散係数（apparent diffusion coefficient：ADC）がλ1となり，それに垂直な方向がλ2，3となる²⁾（Fig. 1, 2）．方向と大きさのあるテンソルモデルを用いることで，白質の可視化と定量化の2つが可能となる．

　可視化に関しては，線維の方向を色で表示するcolor mapやFACT法（fiber assignment by continuous tracking）により拡散テンソル楕円体の長軸を辿り白質路を描出する拡散テンソルtractographyなどがある（Fig. 1-3）．これらは従来の画像診断装置では描出することのできなかった白質路が可視化できるユニークな方法である^21,23)（Fig. 4-6）．

参考文献

1）Abe O, Aoki S, Hayashi N, Yamada H, Kunimatsu A, Mori H, Yoshikawa T, Okubo T, Ohtomo K：Normal aging in the central nervous system：quantitative MR diffusion-tensor analysis. Neurobiol Aging 23：433-441, 2002

2）阿部　修，増谷佳孝，青木茂樹（編）：これでわかる拡散MRI．第2版，秀潤社，2005

3）Acosta-Cabronero J, Williams GB, Pengas G, Nestor PJ：Absolute diffusivities define the landscape of white matter degeneration in Alzheimer's disease. Brain 133 (Pt 2)：529-539, 2010

4）Aoki S, Iwata NK, Masutani Y, Yoshida M, Abe O, Ugawa Y, Masumoto T, Mori H, Hayashi N, Kabasawa H, Kwak S, Takahashi S, Tsuji S, Ohtomo K：Quantitative evaluation of the pyramidal tract segmented by diffusion tensor tractography：feasibility study in patients with amyotrophic lateral sclerosis. Radiat Med 23：195-199, 2005

5）荒木　力：Q-space imaging．pp211-229（荒木　力（著）：拡散MRI─ブラウン運動，拡散テンソルからq空間．秀潤社，2006）

6）Basser PJ, Mattiello J, LeBihan D：Estimation of the effective self-diffusion tensor from the NMR spin echo. J Magn Reson B 103：247-254, 1994

7）Behrens TEJ, Johansen-Berg H, Woolrich MW, Smith SM, Wheeler-Kingshott CA, Boulby PA, Barker GJ, Sillery EL, Sheehan K, Ciccarelli O, Thompson AJ, Brady JM, Matthews PM：Non-invasive mapping of connections between human thalamus and cortex using diffusion imaging. Nat Neurosci 6：750-757, 2003

8）Callaghan PT, Coy A, MacGowan D, Packer KJ, Zelaya FO：Diffraction-like effects in NMR diffusion studies of fluids in porous solids. Nature 351：467-469, 1991

9）Elhawary H, Liu H, Patel P, Norton I, Rigolo L, Papademetris X, Hata N, Golby AJ：Intra-operative real-time querying of white matter tracts during frameless stereotactic neuronavigation. Neurosurgery 68：506-516, 2011

10）Falangola MF, Jensen JH, Babb JS, Hu C, Castellanos FX, Di Martino A, Ferris SH, Helpern JA：Age-related non-Gaussian diffusion patterns in the prefrontal brain. J Magn Reson Imaging 28：1345-1350, 2008

11）Fatima Z, Motosugi U, Hori M, Ishigame K, Kumagai H, Ikenaga S, Onodera T, Yagi K, Araki T：q-space imaging (QSI) of the brain：comparison of displacement parameters by QSI and DWI. Magn Reson Med Sci 9：109-110, 2010

12）Goebell E, Paustenbach S, Vaeterlein O, Ding XQ, Heese O, Fiehler J, Kucinski T, Hagel C, Westphal M, Zeumer H：Low-grade and anaplastic gliomas：differences in artchitecture evaluated with diffusion-tensor MR imaging. Radiology 239：217-222, 2006

13）Jensen JH, Helpern JA：MRI quantification of non-Gaussian water diffusion by kurtosis analysis. NMR Biomed 23：698-710, 2010

14）Jiang Q, Zhang ZG, Chopp M：MRI evaluation of white matter recovery after brain injury. Stroke 41：S112-113, 2010

15）Kamada K, Todo T, Ota T, Ino K, Masutani Y, Aoki S, Takeuchi F, Kawai K, Saito N：The motor-evoked potential threshold evaluated by tractography and electrical stimulation. J Neurosurg 111：785-795, 2009

16）King MD, Houseman J, Roussel SA, van Bruggen N, Williams SR, Gadian DG：q-Space imaging of the brain. Magn Reson Med 32：707-713, 1994

17）Kinoshita M, Yamada K, Hashimoto N, Kato A, Izumoto S, Baba T, Maruno M, Nishimura T, Yoshimine T：Fiber-tracking does not accurately estimate size of fiber bundle in pathological condition：initial neurosurgical experience using neuronavigation and subcortical white matter stimulation. Neuroimage 25：424-429, 2005

18）Kumar R, Husain M, Gupta RK, Hasan KM, Haris M, Agarwal AK, Pandey CM, Narayana PA：Serial changes in the white matter diffusion tensor imaging metrics in moderate traumatic brain injury and correlation with neuro-cognitive function. J Neurotrauma 26：481-495, 2009

19）Kunimatsu A, Itoh D, Nakata Y, Kunimatsu N, Aoki S, Masutani Y, Abe O, Yoshida M, Minami M, Ohtomo K：Utilization of diffusion tensor tractography in combination with spatial normalization to assess involvement of the corticospinal tract in capsular/pericapsular stroke：Feasibility and clinical implications. J Magn Reson Imaging 26：1399-1404, 2007

20）Maruyama K, Koga T, Kamada K, Ota T, Itoh D, Ino K, Igaki H, Aoki S, Masutani Y, Shin M, Saito N：Arcuate fasciculus tractography integrated into Gamma Knife surgery. J Neurosurg 111：520-526, 2009

21）Masutani Y, Aoki S, Abe O, Hayashi N, Ohtomo K：MR diffusion tensor imaging：recent advance and new techniques for diffusion tensor visualization. Eur J Radiol 46：53-66, 2003

22）Matsushita M, Hosoda K, Naitoh Y, Yamashita H, Kohmura E：Utility of diffusion tensor imaging in the acute stage of mild to moderate traumatic brain injury for detecting white matter lesions and predicting long-term cognitive function in adults. J Neurosurg 115：130-139, 2011

23）Mori S, Crain BJ, Chacko VP, van Zijl PC：Three dimensional tracking of axonal projections in the brain by magnetic resonance imaging. Ann Neurol 45：265-269, 1999

24）Nimsky C, Ganslandt O, Hastreiter P, Wang R, Benner T, Sorensen AG, Fahlbusch R：Preoperative and intraoperative diffusion tensor imaging-based fiber tracking in glioma surgery. Neurosurgery 56：130-138, 2005

25）Nossek E, Korn A, Shahar T, Kanner AA, Yaffe H, Marcovici D, Ben-Harosh C, Ben Ami H, Weinstein M, Shapira-Lichter I, Constantini S, Hendler T, Ram Z：Intraoperative mapping and monitoring of the corticospinal tracts with neurophysiological assessment and 3-dimensional ultrasonography-based navigation. Clinical article. J Neurosurg 114：738-746, 2011

26）Ong HH, Wehrli FW：Quantifying axon diameter and intra-cellular volume fraction in excised mouse spinal cord with q-space imaging. Neuroimage 51：1360-1366, 2010

27）Powell HW, Parker GJ, Alexander DC, Symms MR, Boulby PA, Wheeler-Kingshott CA, Barker GJ, Koepp MJ, Duncan JS：MR tractography predicts visual field defects following temporal lobe resection. Neurology 65：596-599, 2005

28）Prabhu SS, Gasco J, Tummala S, Weinberg JS, Rao G：Intraoperative magnetic resonance imaging-guided tractography with integrated monopolar subcortical functional mapping for resection of brain tumors. Clinical article. J Neurosurg 114：719-726, 2011

29）Raab P, Hattingen E, Franz K, Zanella FE, Lanfermann H：Cerebral gliomas：diffusional kurtosis imaging analysis of microstructural differences. Radiology 254：876-881, 2010

30）Romano A, D’andrea G, Calabria LF, Coppola V, Espagnet CR, Pierallini A, Ferrante L, Fantozzi L, Bozzao A：Pre-and intra-operative tractographic evaluation of corticospinal tract shift. Neurosurgery 69：696-705, 2011

31）Shinoura N, Suzuki Y, Yamada R, Tabei Y, Saito K, Yagi K：Damage to the right superior longitudinal fasciculus in the inferior parietal lobe plays a role in spatial neglect. Neuropsychologia 47：2600-2603, 2009

32）Smith SM, Jenkinson M, Johansen-Berg H, Rueckert D, Nichols TE, Mackay CE, Watkins KE, Ciccarelli O, Cader MZ, Matthews PM, Behrens TE：Tract-based spatial statistics：voxelwise analysis of multi-subject diffusion data. Neuroimage 31：1487-1505, 2006

33）Song SK, Sun SW, Ju WK, Lin SJ, Cross AH, Neufeld AH：Diffusion tensor imaging detects and differentiates axon and myelin degeneration in mouse optic nerve after retinal ischemia. Neuroimage 20：1714-1722, 2003

34）Song SK, Yoshino J, Le TQ, Lin SJ, Sun SW, Cross AH, Armstrong RC：Demyelination increases radial diffusivity in corpus callosum of mouse brain. Neuroimage 26：132-140, 2005

35）Taoka T, Sakamoto M, Nakagawa H, Nakase H, Iwasaki S, Takayama K, Taoka K, Hoshida T, Sakaki T, Kichikawa K：Diffusion tensor tractography of the Meyer loop in cases of temporal lobe resection for temporal lobe epilepsy：correlation between postsurgical visual field defect and anterior limit of Meyer loop on tractography. AJNR Am J Neuroradiol 29：1329-1334, 2008

36）Tuch DS：Q-ball imaging. Magn Reson Med 52：1358-1372, 2004

37）Yasokawa YT, Shinoda J, Okumura A, Nakayama N, Miwa K, Iwama T：Correlation between diffusion-tensor magnetic resonance imaging and motor-evoked potential in chronic severe diffuse axonal injury. J Neurotrauma 24：163-173, 2007

38）Yogarajah M, Focke NK, Bonelli S, Cercignani M, Acheson J, Parker GJ, Alexander DC, McEvoy AW, Symms MR, Koepp MJ, Duncan JS：Defining Meyer's loop-temporal lobe resections, visual field deficits and diffusion tensor tractography. Brain 132：1656-1668, 2009

39）Yogarajah M, Focke NK, Bonelli SB, Thompson P, Vollmar C, McEvoy AW, Alexander DC, Symms MR, Koepp MJ, Duncan JS：The structural plasticity of white matter networks following anterior temporal lobe resection. Brain 133：2348-2364, 2010

40）Yoshioka H, Horikoshi T, Aoki S, Hori M, Ishigame K, Uchida M, Sugita M, Araki T, Kinouchi H：Diffusion tensor tractography predicts motor functional outcome in patients with spontaneous intracerebral hemorrhage. Neurosurgery 62：97-103, 2008