Diffusion tensor imaging of lumbar spinal nerve in subjects with degenerative lumbar disorders Yasuhiro Oikawa, Yawara Eguchi, Gen Inoue, Kazuyo Yamauchi, Sumihisa Orita, Hiroto Kamoda, Tetsuhiro Ishikawa, Masayuki Miyagi, Miyako Suzuki, Yoshihiro Sakuma, Go Kubota, Kazuhide Inage, Takeshi Saino, Hirotaka Sato, Hiroki Ando, Masatoshi Kojima, Kenichiro Okumura, Yoshitada Masuda, Atsuya Watanabe, Kazuhisa Takahashi, Seiji Ohtori PII: DOI: Reference:

S0730-725X(15)00122-8 doi: 10.1016/j.mri.2015.05.002 MRI 8362

To appear in:

Magnetic Resonance Imaging

Received date: Revised date: Accepted date:

17 October 2014 18 March 2015 1 May 2015

Please cite this article as: Oikawa Yasuhiro, Eguchi Yawara, Inoue Gen, Yamauchi Kazuyo, Orita Sumihisa, Kamoda Hiroto, Ishikawa Tetsuhiro, Miyagi Masayuki, Suzuki Miyako, Sakuma Yoshihiro, Kubota Go, Inage Kazuhide, Saino Takeshi, Sato Hirotaka, Ando Hiroki, Kojima Masatoshi, Okumura Kenichiro, Masuda Yoshitada, Watanabe Atsuya, Takahashi Kazuhisa, Ohtori Seiji, Diffusion tensor imaging of lumbar spinal nerve in subjects with degenerative lumbar disorders, Magnetic Resonance Imaging (2015), doi: 10.1016/j.mri.2015.05.002

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ACCEPTED MANUSCRIPT Diffusion tensor imaging of lumbar spinal nerve in subjects with degenerative

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lumbar disorders

Yasuhiro Oikawa a,*, Yawara Eguchi a, Gen Inoue c , Kazuyo Yamauchi a , Sumihisa Orita a,

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Hiroto Kamoda a, Tetsuhiro Ishikawa a, Masayuki Miyagi a, Miyako Suzuki a, Yoshihiro Sakuma a, Go Kubota 1, Kazuhide Inage a, Takeshi Saino a, Hirotaka Sato b, Hiroki Ando b,

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Masatoshi Kojima b, Kenichiro Okumura b, Yoshitada Masuda b, Atsuya Watanabe a,

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Kazuhisa Takahashi a , Seiji Ohtori a

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Inohana, Chuo-Ku, Chiba, Japan

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Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1

Department of Radiology, Chiba University Hospital, 1-8-1 Inohana, Chuo-Ku, Chiba, Japan

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Department of Orthopaedic Surgery, School of Medicine, Kitasato University, Kitasato1-15-1,

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Sagamihara City, Kanagawa, Japan

Corresponding author: Yasuhiro Oikawa, MD

Department of Orthopaedic Surgery, Graduate School of Medicine Chiba University 1-8-1 Inohana, Chuo-Ku Chiba, 260-8670, Japan Tel.: +81-43-226-2117; Fax: +81-43-2116. E-mail address: [email protected]

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ACCEPTED MANUSCRIPT All subjects were studied after informed consent, and the study had prior approval of the Chiba University Ethics Committee.

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This study was supported by a medical research grant on traffic accident from The General Insurance Association of Japan. We did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity.

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Abstract

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Recently several authors have reported that diffusion tensor imaging (DTI) might provide a new

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understanding of sciatica. The purpose of this study was to investigate the clinical feasibility of DTI for the evaluation of lumbar spinal nerve of patients with sciatica associated with lumbar

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degenerative disorders. Thirty-four patients (25men, mean age63. 3 years) with degenerated

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lumbar disease, 14 patients with lumbar spinal stenosis with foraminal stenosis, 12 with lumbar spinal stenosis without foraminal stenosis, five with lumbar disc herniation, two with discogenic

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low back pain, and one with spondylolysis who underwent 3.0 T magnetic resonance (MR) imaging and surgical treatment were included in the present study. Fractional anisotropy (FA)

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was calculated from an FA map and tractography was investigated. In asymptomatic nerves,

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tractography showed all L3–S1 spinal nerve roots clearly. Abnormalities of tractography were classified into three types by shape; “Disrupted”, ”Narrowing”, and “Tapering”. More

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abnormalities of tractography were found in patients with lumbar spinal stenosis, and especially

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in patients with foraminal stenosis., The Disrupted type was the most common. The mean FA of entrapped symptomatic nerves was less than seen on the intact side. This study demonstrates that tractography shows abnormal findings for nerve roots in lumbar spinal degeneration and that FA decreases in symptomatic roots. DTI may offer not only morphological evaluation, but also quantitative evaluation. We believe that DTI can be used as a tool for the diagnosis of lumbar spinal degenerative disease. Key words: Diffusion tensor imaging, Fractional anisotropy, Lumbar spinal stenosis, Magnetic resonance imaging.

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ACCEPTED MANUSCRIPT 1. Introduction Imaging plays an important role in the diagnosis of degenerative lumbar diseases with sciatica

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and radicular symptoms affecting leg pain. However, discrepancies between clinical symptoms

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and imaging are often found. Although conventional imaging modalities for the lumbar spinal degenerative disease, such as radiography, computed tomography (CT), myelography and

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magnetic resonance (MR) imaging, have a good potential for morphological evaluation, these

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conventional imaging techniques do not provide any effective means for quantitative evaluation of nerve damage.

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Diffusion-weighted imaging (DWI) can provide valuable information regarding the microstructure of tissues by applying a motion probing gradient (MPG) in some directions to

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monitor the random movement of water molecules, which is restricted in tissues.1-4 DWI has

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been widely used in the clinic to evaluate the central nervous system for the diagnosis of diseases such as acute brain stroke.5 If there is no directional variation rate in tissues, diffusion is said to

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be isotropic. By contrast, water molecules tend to move along the nerve fibers in neural tissue

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and this is called anisotropic diffusion. The diffusion data can be used to determine quantitative diffusion values such as the apparent diffusion coefficient (ADC) and a scalar fractional anisotropy (FA) value that reflects the directionality of molecular diffusion. Diffusion tensor tractography (DTT) uses diffusion tensor imaging (DTI) to visualize highly anisotropic nerve fiber tracts. Several studies have shown that DTI is useful for the evaluation and visualization of peripheral nerves 6 and the measurement of axon regeneration in rat 7 and mouse 8 sciatic nerves, demonstrating that a decrease in mean FA is observed in injured nerves with demyelination.6-9 Recently, several authors reported that DTI could visualize lumbar spinal nerves.10-14 To our knowledge, this is the first study to evaluate DTI and FA values of lumbar 4

ACCEPTED MANUSCRIPT spinal nerve of consecutive patients with lumbar degenerative disorders including lumbar spinal canal stenosis. The purpose of this study was to investigate the clinical feasibility of DTI for the

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evaluation of lumbar spinal nerve of patients with sciatica associated with lumbar degenerative

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disorders.

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2. Materials and Methods

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2.1 Subjects

Our study received prior approval from our Institutional Review Board and Ethics Committee.

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Thirty-four consecutive patients (25 men; mean age, 63.3 years) with the degenerated lumbar disease who underwent 3.0 T MR imaging and surgical treatment were included. Patients with a

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previous history of spinal trauma, surgery, neurological disease, or contraindication to MR

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imaging were excluded. Fourteen patients with lumbar spinal stenosis (LSS) with foraminal stenosis (FS), 12 with LSS without FS, five with lumbar disc herniation, two with discogenic low

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back pain, and one with spondylolysis were investigated in this study (Table 1). Their

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pre-surgical diagnosis was based on neurological findings; a selective nerve root block; and a combination of diagnostic imaging, including plain radiographs, CT, and conventional MR imaging. Ten healthy volunteers (10men; mean age, 33.8 years) served as controls. All volunteers were asymptomatic and had no history of low back pain or sciatica. 2.2 DTI Protocol A 3T MR imaging scanner (Discovery MR750; GE Healthcare, Milwaukee, Wis) was used in this study. Subjects were scanned in a supine position using a Sense XL Torso coil. In all subjects, DTI was performed using a special sensitivity array encoding technique, factor: 2; chemical shift selective suppression; and an echo-planar imaging sequence with a free-breathing scanning 5

ACCEPTED MANUSCRIPT technique. The following imaging parameters were set: 800 s/mm2 b-value; MPG, 11 directions; 6000/76 ms for TR/TE, respectively; axial section orientation, 3/0-mm section thickness/gap;

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320 × 256 mm FOV; 96 × 192 matrix; 3.3 × 1.66 × 3.0 mm3 actual voxel size; 1.6 × 1.6 × 4.0

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mm3 calculated voxel size; 4 excitations; 50 total sections; and 4 min 54 s scan time. 2.3 Image analysis

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Analysis was performed on a personal computer using Volume-One software (http://

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www.volume-one.org/), dTVIISR (diffusion TENSOR Visualizer II) software (second release; ;http://www.ut-radiology.umin.jp/people/ masutani/dTV.htm) 21 , and on a work station

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using Functool DTI processing (GE Healthcare) for tractography and FA mapping. The diffusion tensor was calculated by using a log–linear fitting method. The regions of interest (ROIs) were

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placed on the spinal nerve: “intraspinal”, “intraforaminal”, and “extraforaminal” zones (Fig. 1).

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Fiber tracking was performed by placing ROIs at intraspinal and extraforaminal zones. The mean FA was calculated with the software at each ROIs of spinal nerves from L3 to S1 in

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patients and healthy volunteers. The mean value of three slices was calculated and the average of

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the FA values was recorded. The size of ROIs ranging from 25 to 55mm2 (mean. 42.1 ± 7.6mm2) was selected to be as accurate as possible for the respective spinal nerves to avoid partial volume effects when the mean FA was calculated. In this study, CSFcontamination effects were considered to be negligible because the section thickness was 3mm and therefore smaller than the L5 dorsal root ganglia size, which is about 5 mm wide and 10 mm long. All DTI analyses were performed twice by two trained spine surgeons to evaluate intra- and interobserver differences. The evaluation of tractography included abnormalities of spinal nerves such as disrupted, narrowing, and tapering. 2.4 Statistical analysis 6

ACCEPTED MANUSCRIPT Statistical analyses were performed with Stat View version 5.0 software (SAS Institute, Cary, N C). A post hoc test was used to compare FA between healthy volunteers and patients with lumbar

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foraminal stenosis at L3–S1 spinal nerves. Comparisons of spinal nerves FA values at the

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stenotic level between the entrapped side and intact side in the same subject were also conducted.

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P < .05 was considered significant.

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3. Results 3.1 Tractography of healthy subjects

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In healthy volunteers, the tractography clearly showed all L3–S1 spinal nerves. L3–S1 spinal nerves coursed symmetrically and obliquely downward, and merged with T2-WI, it

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could be clearly observed that spinal nerves from intra-spinal canal to extra-foraminal zone were

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successively (Fig. 2).

3.2 Classification of the tractography

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By contrast with the normal spinal nerves, there are some abnormalities of tractography in

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patients with asymptomatic spinal nerves. Abnormalities of tractographies were classified into three types by the shape: “Disrupted”, “Narrowing”, and “Tapering” (Fig. 3). 3.3 FA values of healthy subjects and patients In intact nerves, FA values (mean ± SD) of nerves were 0.247 ± 0.070 for intraspinal, 0.323 ± 0.060 for intraforaminal, and 0.337 ± 0.059 for extraforaminal zones (Fig. 4-1). The FA of the intraspinal zone was significantly less than for the intraforaminal and extraforaminal zones, and that for the intraforaminal zone was significantly less than for the extraforaminal zone. Differences were not found between each level of spinal nerve (L3‒S1) (Fig. 4-2). By contrast, in the nerves with Disrupted, the mean FA of intraforaminal zones was 0.288 ± 0.047, which is 7

ACCEPTED MANUSCRIPT significantly less than the 0.323 ± 0.060 seen in intact spinal nerves. However, differences were not found in FA of intraspinal and extraforaminal zones. In the nerves with Narrowing, the mean

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FA of intraforaminal zones was 0.300 ± 0.048, which is significantly less than the 0.323 ± 0.060

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seen in intact spinal nerves. However, differences were not found in FA of intraspinal and extraforaminal zones. In the nerves with Tapering, the mean FA of extraforaminal zones were

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0.280 ± 0.056, which is significantly less than the 0.337± 0.059 seen in intact spinal nerves.

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However, differences were not found in the FA of intraspinal and intraforaminal zones (Fig. 5). The mean FA of symptomatic nerves on entrapment was 0.266, which is less than the 0.329 seen

than the 0.329 seen on the intact side.

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on the intact side. The mean FA of symptomatic nerves on entrapment was 0.266, which is less

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3.4 Distribution of abnormalities of DTI in patients

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In the 14 patients with lumbar spinal stenosis (LSS) with foraminal stenosis (FS), five Disrupted, six Narrowing, two Tapering, and only one without abnormalities were found. In the 12 patients

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with LSS without FS, one Disruption, six Narrowing, one Tapering, and only four without

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abnormalities were found (Table 2). No abnormalities were observed in lumbar disc herniation, discogenic low back pain, and spondylolysis. In the patients with LSS, more abnormalities of tractography were found, and in patients with foraminal stenosis, more abnormalities with a characteristic distribution in the Disrupted type were found compared with patients without foraminal stenosis.

4. Discussion Developmental narrowing of the lumbar vertebral canal causes radicular syndrome16, which is usually related to the level of the responsible lesion. However, in some patients the level of 8

ACCEPTED MANUSCRIPT stenosis on the image does not correlate with the neurological findings and the origin of radiculopathy remains complicated and controversial. Furthermore, lumbar foraminal stenosis

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often unfortunately results in failed back surgery syndrome because of the difficulty in making a

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correct diagnosis.17-19 Conventional MR imaging has been inadequate for evaluating symptomatic foraminal stenosis.20 New diagnostic imaging techniques to detect lumbar spinal

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nerve entrapment are urgently required.

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Although peripheral nerves cannot be selectively visualized by conventional MR imaging by using T1- and T2-weighted imaging, Yamashita et al21 have demonstrated the feasibility of

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whole-body MR neurography with the use of DWI that can depict tissues with an impeded diffusion, such as tumors, brain, spinal cord, and peripheral nerves. MR neurography by using

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DWI can clearly show lumbar spinal nerves, and the mean ADC in nerve root entrapment with

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foraminal stenosis is higher than in intact nerve roots by using MR imaging at 1.5 T.22 The

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ADC map is limited because the tissue contrast between the nerves and surrounding tissues is

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We have previously reported that DTI can clearly show tractography of lumbar spinal nerves and determine the FA of the spinal nerves in patients with lumbar foraminal stenosis and healthy volunteers by using MR imaging at 3 T.11, 12 A few recent DTI studies of lumbar spinal nerve were demonstrated by Balbi et al. 10 at 1.5 T, van der Jagt et al.13 and Budzik et al.14 at 3 T. To the our knowledge, this is the first study to evaluate DTI and FA of lumbar spinal nerves of consecutive patients with lumbar degenerative disorders including lumbar spinal stenosis (LSS). In this study, in intact nerves, the mean FA was 0.247 for intraspinal, 0.323 for intraforaminal, and 0.337 for extraforaminal zones and differences were not found between each level of nerve roots (L3‒S1). Our FA values are comparable to those obtained in the study of lumbar spinal 9

ACCEPTED MANUSCRIPT nerves by Balbi et al.10 (0.218), van der Jagt et al.13 (0.31), and Budzik et al.14 (0.38). By contrast, the mean FA of symptomatic nerves on entrapment was less than that seen on the

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intact side. In patients with LSS, more abnormalities of tractography were found, and especially

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in patients with foraminal stenosis, more abnormalities with a characteristic distribution in the Disrupted type were found. Although the mechanisms of decreasing FA in nerve entrapment have

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been controversial, these findings suggest that diffusion in the tissue had become more isotropic

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because of edema, in which fluid is trapped in the tissue, creating an isotropic environment and a reduction in FA. These hypotheses have been supported by previous experimental studies.

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Beaulieu et al.2, 3 reported that Wallerian degeneration after peripheral nerve injury reduces the anisotropy of water diffusion. Several studies indicated that the FA of peripheral nerves was

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strongly correlated with axonal degeneration and regeneration in rat and mouse sciatic nerves.7, 8

We acknowledge that our study has several limitations. The first is that a small number of

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subjects were investigated. Further studies are needed to investigate whether our findings remain

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valid in a larger population. Second, we could not repeat the DTI after surgery because of spinal instrumentation artifacts, such as those from pedicle screw systems. Third, that tracts might be apparently missing in tractography of patients with stenosis does not necessarily indicate loss of nerve fibers or paralysis, but that there is some isotropic change and FA reduction. Moreover, the number of tracts visualized by DTI dose not present the actual volume of nerve fiber trajectories. Beaulieu et al. reported that Wallerian degeneration after peripheral nerve injury reduces the anisotropy of water diffusion3. Several investigators have reported FA values for lumbar spinal nerves, which were less in compressed nerves than for intact nerves2,4,5. This study showed trends for the FA of lumbar spinal nerves. FA increases further from the intraspinal zone and is 10

ACCEPTED MANUSCRIPT less in symptomatic roots. Finally, we acknowledged the limitations of echo planar imaging related with susceptibility

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artifacts. The disrupted shape of tractography might be explained by susceptibility artifacts

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caused by bone spurs and foraminal narrowing. We previously reported that abnormalities such as disruption of nerve fibers were only accurately detected on symptomatic root by DTI,

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although asymptomatic foraminal stenosis on the foramina were found by conventional MR

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imaging11. These findings indicated that DTI disruption was strongly correlated with symptomatic roots rather than susceptibility artifacts. In this study using 3T, no abnormalities

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were found in five patients with lumbar disc herniation. In another study using 1.5T, tractography was visualized in the spinal canal and disrupted by disc herniation. It was possible that

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abnormalities were unrecognized because tractography was not visualized in the spinal canal due

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5. Conclusion

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to susceptibility artifacts by high magnetic field using 3T.

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This study demonstrates that tractography shows abnormal findings for spinal nerves in lumbar spinal degeneration and so DTI may offer not only morphological evaluation, but also quantitative evaluation. We believe that DTI is a potential tool for the diagnosis of lumbar spinal degenerative disorders.

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ACCEPTED MANUSCRIPT References

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1. Basser PJ, Jones DK. Diffusion tensor MRI: theory, experimental design and data analysis-a

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technical review. NMR Biomed 2002;15:456–67

2. Beaulieu C, Allen PS. Determinants of anisotropic water diffusion in nerves. Magn Reson Med

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1994;31:394–400

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3. Beaulieu C, Does MD, Snyder RE, Allen PS. Changes in water diffusion due to Wallerian degeneration in peripheral nerve. Magn Reson Med 1996;36:627–31

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4. Basser PJ, Pierpaoli C. Microstructural and physiological features of tissues elucidated by quantitative-diffusion-tensor MRI. J Magn Reson B 1996;111:209–19

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5. Minematsu K, Fisher M, Li L, Davis MA, Knapp AG, Cotter RE, McBurney RN, Sotak CH.

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Diffusion-weighted magnetic resonance imaging: rapid and quantitative detection of focal brain ischemia. Neurology 1992;42:235–40

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6. Khalil C, Hancart C, Le Thuc V, Chantelot C, Chechin D, Cotten A. Diffusion tensor imaging

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and tractography of the median nerve in carpal tunnel syndrome: preliminary results. Eur Radiol 2008;18:2283–91

7. Lehmann HC, Zhang J, Mori S, Sheikh KA. Diffusion tensor imaging to assess axonal regeneration in peripheral nerves. Exp Neurol 2010;223:238–44 8. Takagi T, Nakamura M, Yamada M, Hikishima K, Momoshima S, Fujiyoshi K, Shibata S, Okano HJ, Toyama Y, Okano H. Visualization of peripheral nerve degeneration and regeneration: monitoring with diffusion tensor tractography. Neuroimage 2009;44:884–92 9. MacDonald CL, Dikranian K, Bayly, P, Holtzman D, Brody D. Diffusion tensor imaging reliably detects experimental traumatic axonal injury and indicates approximate time of injury. J 12

ACCEPTED MANUSCRIPT Neurosci 2007;27:11869–76 10. Balbi V, Budzik JF, Duhamel A, Bera-Louville A, Le Thuc V, Cotten A. Tractography of

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lumbar nerve roots: initial results. Eur Radiol. 2011;21(6):1153-9

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11. Eguchi Y, Ohtori S, Orita S, Kamoda H, Arai G, Ishikawa T, Miyagi M, Inoue G, Suzuki M, Masuda Y, Andou H, Takaso M, Aoki Y, Toyone T, Watanabe A, Takahashi K. Quantitative

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Evaluation and Visualization of Lumbar Foraminal Nerve Root Entrapment Using Diffusion

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Tensor Imaging: Preliminary Results. Am. J. Neuroradiol. 2011;32: 1824-9 12. Kitamura M, Eguchi Y, Inoue G, Orita S, Takaso M, Ochiai N, Kishida S, Kuniyoshi K, Aoki

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Y, Nakamura J, Ishikawa T, Arai G, Miyagi M, Kamoda H, Suzuki M, Furuya T, Toyone T, Takahashi K, Ohtori S. A case of symptomatic extra-foraminal lumbosacral stenosis ("far-out

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syndrome") diagnosed by diffusion tensor imaging. Spine 2012;37:E854-7

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13. van der Jagt PK, Dik P, Froeling M, Kwee TC, Nievelstein RA, ten Haken B, Leemans A. Architectural configuration and microstructural properties of the sacral plexus: a diffusion tensor

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MRI and fiber tractography study. Neuroimage. 2012 Sep;62:1792-9

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14. Budzik JF, Verclytte S, Lefebvre G, Monnet A, Forzy G, Cotten A. Assessment of reduced field of view in diffusion tensor imaging of the lumbar nerve roots at 3 T.Eur Radiol. 2013; 23:1361-6

15. Masutani Y, Aoki S, Abe O, Naoto Hayashi N, Otomo K. MR diffusion tensor imaging: recent advance and new techniques for diffusion tensor visualization. Eur J Radiol 2003;46:53–66 16. Verbiest H (1954) A radicular syndrome from developmental narrowing of the lumbar vertebral canal. J Bone Joint Surg Br 36: 230-237. 17. Jenis LG, An HS. Spine Update. Lumbar foraminal stenosis. Spine 2000;25:389–94 13

ACCEPTED MANUSCRIPT 18. Burton R, Kirkaldy-Willis W, Yong-Hing K, Heithoff K. Causes of failure of surgery on the lumbar spine. Clin Orthop 1981;157:191–7

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sixty-eight patients. J Bone Joint Surg Am 1971;53:891–903

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19. MacNab I. Negative disc exploration: An analysis of the causes of nerve root involvement in

20. Aota Y, Niwa T, Yoshikawa K, Fujiwara A, Asada T, Saito T. Magnetic resonance imaging

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and magnetic resonance myelography in the presurgical diagnosis of lumbar foraminal stenosis.

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Spine 2007;32:896–03

21. Yamashita T, Kwee TC, Takahara T. Whole-body magnetic resonance neurography. N Engl J

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Med 2009;361:538–9

22. Eguchi Y, Ohtori S, Yamashita M, Yamauchi K, Suzuki M, Orita S, Kamoda H, Arai G,

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Ishikawa T, Miyagi M, Ochiai N, Kishida S, Masuda Y, Ochi S, Kikawa T, Takaso M, Aoki Y,

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Toyone T, Suzuki T, Takahashi K. Clinical applications of diffusion magnetic resonance imaging

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of the lumbar foraminal nerve root entrapment. Eur Spine J 2010;19:1874–82

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ACCEPTED MANUSCRIPT Legends

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Table 1. Patient characteristics

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Table 2. Distribution of abnormalities in patients

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Fig. 1. Zone definition of the spinal nerve root at the spinal canal.

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The area between the inner edge of both pedicles was defined as the intraspinal zone (a), the width of pedicle was defined as the intraspinal zone (b), and the area outer to the outer edge of

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pedicle was defined as the extraforaminal zone (c).

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Fig. 2. In asymptomatic nerves, tractography showed all L3‒S1 spinal nerve roots clearly

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Merged with T2-WI, the spinal nerve root from the intraspinal zone to the extraspinal zone was

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observed clearly.

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Fig. 3. Abnormality of tractographies was classified into three types by the shape: “Disrupted”, “Narrowing”, and “Tapering” The tractography that was not drawn in succession was defined as “Disrupted”,that which continues unclearly compared with the intact side was defined as “Narrowing”, and that which was not visualized at the extraforaminal zone was defined as “Tapering”.

Fig. 4. In normal nerve roots, FA (mean ± SD) of nerves was 0.247 ± 0.070 for intraspinal, 0.323 ± 0.060 for intraforaminal, and 0.337 ± 0.059 for extraforaminal zones (4-1). The FA of the intraspinal zone was significantly less than that of intraforaminal and extraforaminal zones, and 15

ACCEPTED MANUSCRIPT that of the intraforaminal zone was significantly less than that of the extraforaminal zone. FA values for the intraspinal zone were 0.226 ± 0.042 at the L3 nerve root, 0.244 ± 0.085 at the

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L4 nerve root, 0.238 ± 0.081 at the L5 nerve root, and 0.238 ± 0.055 at the S1 nerve root. FA

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values for the intraforaminal zone were 0.313 ± 0.052 at L3, 0.339 ± 0.074 at L4, 0.328 ± 0.061 at L5, and 0.314 ± 0.050 at S1. FA values for extraforaminal zone were 0.339 ± 0.061 at L3,

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0.332 ± 0.059 at L4, 0.331± 0.069 at L5, and 0.343 ± 0.051 at S1. Differences were not found

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between nerve root levels (L3‒S1) (4-2).

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Fig. 5. The mean FA of intraforaminal zones was 0.288 ± 0.047 in the Disrupted type and 0.300 ± 0.048 in the Narrowing type, which is significantly less than that for normal nerve roots.

The

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mean FA of extraforaminal zones was 0.280 ± 0.056 in the Tapering type, significantly less than

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for normal nerve .

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ACCEPTED MANUSCRIPT Table 1 men: 25, women: 9, mean age: 63.3 y.o.

Diagnosis(n)

Lumbar spinal stenosis with Foraminal stenosis: 14

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Patients

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Lumbar spinal stenosis without Foraminal stenosis: 12

Discogenic low backpain: 2

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Spondylolysis: 1

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Lumbar disc herniation: 5

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LSS* without FS**

Tapering

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(n=12) Lumbar disc herniation

Discogenic Low Backpain

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(n=5)

Spondylolysis

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*: Lumbar Spinal Stenosis ** :Foraminal Stenosis

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(n=1)

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(n=2)

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(n=14)

Narrowing

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LSS* with FS **

Disrupted

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Diffusion tensor imaging of lumbar spinal nerve in subjects with degenerative lumbar disorders.

Recently several authors have reported that diffusion tensor imaging (DTI) might provide a new understanding of sciatica. The purpose of this study wa...
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