Feasibility of 3.0 T diffusion-weighted nuclear magnetic resonance imaging in the evaluation of functional recovery of rats with complete spinal cord injury

Diffusion tensor imaging is a sensitive way to reflect axonal necrosis and degeneration, glial cell regeneration and demyelination following spinal cord injury, and to display microstructure changes in the spinal cord in vivo. Diffusion tensor imaging technology is a sensitive method to diagnose spinal cord injury; fiber tractography visualizes the white matter fibers, and directly displays the structural integrity and resultant damage of the fiber bundle. At present, diffusion tensor imaging is restricted to brain examinations, and is rarely applied in the evaluation of spinal cord injury. This study aimed to explore the fractional anisotropy and apparent diffusion coefficient of diffusion tensor magnetic resonance imaging and the feasibility of diffusion tensor tractography in the evaluation of complete spinal cord injury in rats. The results showed that the average combined scores were obviously decreased after spinal cord transection in rats, and then began to increase over time. The fractional anisotropy scores after spinal cord transection in rats were significantly lower than those in normal rats （P 〈 0.05）; the apparent diffusion coefficient was significantly increased compared with the normal group （P 〈 0.05）. Following spinal cord transection, fractional anisotropy scores were negatively correlated with apparent diffusion coefficient values （r = -0.856, P 〈 0.01）, and positively correlated with the average combined scores （r = 0.943, P 〈 0.01）, while apparent diffusion coefficient values had a negative correlation with the average combined scores （r = -0.949, P 〈 0.01）. Experimental findings suggest that, as a non-invasive examination, diffusion tensor magnetic resonance imaging can provide qualita- tive and quantitative information about spinal cord injury. The fractional anisotropy score and apparent diffusion coefficient have a good correlation with the average combined scores, which reflect functional recovery after spinal cord injury.

Application of magnetic resonance imaging in cervical spondylotic myelopathy

Cervical spondylotic myelopathy(CSM) is the most common cause of spinal cord dysfunction and is caused by static or dynamic repeated compression of the spinal cord resulting from degenerative arthritis of the cervical spine and some biological injuries to the cervical spine. The T2 signal change on conventional magnetic resonance imaging(MRI) is most commonly associated with neurological deficits. Diffusion tensor imaging and MR spectroscopy show altered microstructure and biochemistry that reflect patient-specific pathogenesis and can be used to predict neurological outcome and response to intervention. Functional MRI can help to assess the neurological functional recovery after decompression surgery for CSM.

Magnetic resonance imaging-guided focused ultrasound to increase localized blood-spinal cord barrier permeability

Spinal cord injury（SCI） affects thousands of people every year in the USA, and most patients are left with some permanent paralysis. Therapeutic options are limited and only modestly affect outcome. To address this issue, we used magnetic resonance imaging-guided focused ultrasound（MRg FUS） as a non-invasive approach to increase permeability in the blood-spinal cord barrier（BSCB）. We hypothesize that localized, controlled sonoporation of the BSCB by MRg FUS will aid delivery of therapeutics to the injury. Here, we report our preliminary findings for the ability of MRg FUS to increase BSCB permeability in the thoracic spinal cord of a normal rat model. First, an excised portion of normal rat spinal column was used to characterize the acoustic field and to estimate the insertion losses that could be expected in an MRg FUS blood spinal cord barrier opening. Then, in normal rats, MRg FUS was applied in combination with intravenously administered microbubbles to the spinal cord region. Permeability of the BSCB was indicated as signal enhancement by contrast administered prior to T1-weighted magnetic resonance imaging and verified by Evans blue dye. Neurological testing using the Basso, Beattie, and Breshnahan scale and the ladder walk was normal in 8 of 10 rats tested. Two rats showed minor impairment indicating need for further refinement of parameters. No gross tissue damage was evident by histology. In this study, we have opened successfully the blood spinal cord barrier in the thoracic region of the normal rat spine using magnetic resonance-guided focused ultrasound combined with microbubbles.

Impact of computed tomography/magnetic resonance imaging registration on rehabilitation after percutaneous endoscopic decompression for lumbar stenosis: Retrospective study

BACKGROUND Percutaneous endoscopic lumbar decompression(PELD)shows promise for lumbar spinal stenosis(LSS)treatment,but its use is limited by the disease's complexity and procedural challenges.AIM In this study,the effects of preoperative planning and intraoperative guidance with computed tomography(CT)/magnetic resonance imaging(MRI)registration techniques on PELD for LSS and postoperative rehabilitation outcomes were evaluated.METHODS This retrospective study was conducted with data from patients who underwent PELD for LSS between January 2021 and December 2023.Patients were assigned to preoperative CT/MRI registration and control groups.Data collected included the operative time,length of hospital stay,visual analog scale(VAS)scores for low back and leg pain,and the Japanese Orthopaedic Association(JOA)lumbar spine score.Differences between groups were assessed using Student’s t test.RESULTS Data from 135 patients(71 in the CT/MRI registration group,64 in the control group)were analyzed.The operative time was significantly shorter in the CT/MRI registration group(P=0.007).At 2 months postoperatively,both groups showed significant reductions in VAS leg and low back pain scores(all P<0.001)and improvements in the JOA score(both P<0.001).No complication or death occurred.Preoperatively,pain and JOA scores were similar between groups(P=0.830,P=0.470,and P=0.287,respectively).At 2 months postoperatively,patients in the CT/MRI registration group reported lower leg and low back pain levels(P<0.001 and P=0.001,respectively)and had higher JOA scores(P=0.004)than did patients in the control group.CONCLUSION Preoperative CT/MRI registration for PELD for LSS reduced the operative time and VAS pain scores at 2 months and improved JOA scores,demonstrating enhanced effectiveness and safety.

Intravoxel incoherent motion magnetic resonance imaging for diagnosis of cervical cancer and evaluation of response of uterine cervical cancer to radiochemotherapy: A pilot study

Objective The aim of this study was to investigate the ability of intravoxel incoherent motion(IVIM) diffusion-weighted magnetic resonance imaging(MRI) to diagnose cervical cancer and to evaluate the response of uterine cervical cancer to radiochemotherapy(CRT).Methods This prospective study was approved by the institutional review board, and informed consent was obtained from all patients. A total of 23 patients with primary cervical cancer who were undergoing CRT and 16 age-matched healthy subjects were prospectively recruited for IVIM(b = 0–800 s/mm2) and standard pelvic MRI. Bi-exponential analysis was performed to derive f(perfusion fraction), D*(pseudo-diffusion coefficient), and D(true molecular diffusion coefficient) in cervical cancer(n = 23) and the normal cervix(n = 16). The apparent diffusion coefficient(standard ADC) was calculated. The independent-samples t-test and paired-samples t-test were used for comparisons.Results Pre-treatment cervical cancer had the lowest standard ADC(1.15 ± 0.13 × 10-3 mm2/s) and D(0.89 ± 0.10 × 10-3 mm2/s) values, and these were significantly different from the normal cervix and posttreatment cervical cancer(P = 0.00). The f(16.67 ± 5.85%) was lowest in pre-treatment cervical cancer and was significantly different from the normal cervix and post-treatment cervical cancer(p = 0.012 and 0.00, respectively). No difference was observed in D*.Conclusion IVIM is potentially promising for differentiating between the normal cervix and cervical cancer because pre-treated cervical cancer has low perfusion and diffusion IVIM characteristics. Further, the standard ADC, D, and f of cervical cancer showed a tendency to normalize after CRT; thus, IVIM may be useful for monitoring the response to CRT in cervical cancer.

Quantification of spatial expansion of cervical tumours using Magnetic Resonance Imaging

Objective This research study aims to analyze existing principles regarding the processing and analysis of imaging data and apply these concepts to the setting of the magnetic resonance imaging arena with a main focus on its use in cervical tumours. Any possible models will then be formulated,with the possibility of testing these theories in an experimental study that would involve actual patient data collected from a collaborating healthcare institution. The applicability of quantification of spatial expansion will also be applied to specific cancers and medical conditions that commonly make use of the noninvasive feature of magnetic resonance imaging. Conclusion Diffusionweighted magnetic resonance imaging can be employed in examining the cellular dynamics of tumours as it assists in the localization,as well as displacement of particular cellular structures within a particular volume.

Magnetic resonance diffusion tensor imaging and fibertracking diffusion tensor tractography in the management of spinal astrocytomas

Some specially imaging of magnetic resonance imaging,the diffusion-weighted imaging(DWI),the diffusion tensor imaging and fractional anisotropy(FA),are useful to described,detect,and map the extent of spinal cord lesions.FA measurements may are used to predicting the outcome of patients who have spinal cord lesions.Fiber tracking enable to visualizing the integrity of white matter tracts surrounding some lesions,and this information could be used to formulating a differential diagnosis and planning biopsies or resection.In this article,we will describe the current uses for DWI and fiber tracking and speculate on others in which we believe these techniques will be useful in the future.

Magnetic resonance imaging of the spinal marrow:Basic understanding of the normal marrow pattern and its variant

For now, magnetic resonance (MR) is the best noninvasive imaging modality to evaluate vertebral bone marrow thanks to its inherent soft-tissue contrast and non-ionizing nature. A daily challenging scenario for every radiologist interpreting MR of the vertebral column is discerning the diseased from normal marrow. This requires the radiologist to be acquainted with the used MR techniques to judge the spinal marrow as well as its normal MR variants. Conventional sequences used basically to image marrow include T1W, fat-suppressed T2W and short tau inversion recovery (STIR) imaging provides gross morphological data. Interestingly, using non-routine MR sequences; such as opposed phase, diffusion weighted, MR spectroscopy and contrasted-enhanced imaging; may elucidate the nature of bone marrow heterogeneities; by inferring cellular and chemical composition; and adding new functional prospects. Recalling the normal composition of bone marrow elements and the physiologic processes of spinal marrow conversion and reconversion eases basic understanding of spinal marrow imaging. Additionally, orientation with some common variants seen during spinal marrow MR imaging as hemangiomas and bone islands is a must. Moreover, awareness of the age-associated bone marrow changes as well as changes accompanying different variations of the subject&#x02019;s health state is essential for radiologists to avoid overrating normal MR marrow patterns as pathologic states and metigate unnecessary further work-up.

Spectrum of magnetic resonance imaging findings in congenital lumbar spinal stenosis

AIM: To investigate whether congenital lumbar spinal stenosis(CLSS) is associated with a specific degenerative changes of the lumbar spine. METHODS: The lumbar spine magnetic resonance imaging studies of 52 subjects with CLSS and 48 control subjects were retrospectively evaluated. In each examination, the five lumbar levels were assessed for the presence or absence of circumferential or shallow annular bulges, annular tears, anterior or posterior disc herniations, epidural lipomatosis, Schmorl's nodes,spondylolisthesis, pars defects, and stress reactions of the posterior vertebral elements. RESULTS: Compared to control individuals, subjects with CLSS exhibited increased incidence of circumferential and shallow annular bulges, annular tears, discherniations and spondylolisthesis(P < 0.05). CONCLUSION: CLSS is associated with increased incidence of degenerative changes in specific osseous and soft-tissue elements of the lumbar spine.

Semi-automated segmentation of magnetic resonance images for thigh skeletal muscle and fat using threshold technique after spinal cord injury

Magnetic resonance imaging is considered the ＂gold standard＂ technique for quantifying thigh muscle and fat cross-sectional area. We have developed a semi-automated technique to segment seven thigh compartments in persons with spinal cord injury. Thigh magnetic resonance images from 18 men（18–50 years old） with traumatic motor-complete spinal cord injury were analyzed in a blinded fashion using the threshold technique. The cross-sectional area values acquired by thresholding were compared to the manual tracing technique. The percentage errors for thigh circumference were（threshold： 170.71 ± 38.67; manual： 169.45 ± 38.27 cm2） 0.74%, subcutaneous adipose tissue（threshold： 65.99±30.79; manual： 62.68 ± 30.22） 5.2%, whole muscle（threshold： 98.18 ± 20.19; manual： 98.20 ± 20.08 cm2） 0.13%, femoral bone（threshold： 6.53 ± 1.09; manual： 6.53 ± 1.09 cm2） 0.64%, bone marrow fat（threshold： 3.12 ± 1.12; manual： 3.1 ± 1.11 cm2） 0.36%, knee extensor（threshold： 43.98 ± 7.66; manual： 44.61 ± 7.81 cm2） 1.78% and % intramuscular fat（threshold： 10.45 ± 4.29; manual： 10.92 ± 8.35%） 0.47%. Collectively, these results suggest that the threshold technique provided a robust accuracy in measuring the seven main thigh compartments, while greatly reducing the analysis time.

MAGNETIC RESONANCE IMAGING OF ACUTE CENTRAL CORD SYNDROME: CORRELATION WITH PROGNOSIS

Objective. To report the magnetic resonance imaging (MRI) findings of acute cervical central cord syndrome and to determine their correlation with the prognosis. Methods. MRI findings of 35 patients with acute central cord syndrome were studied and compared with the recovery rate of ASIA score at presentation and in follow- up. Results. MRI data demonstrated spinal cord compression for 32 patients, spinal cord swelling for 16 patients, and abnormal signal intensity within the spinal cord for 19 patients, including 14 with edema and 3 with hematoma. No significant difference of the recovery rate was noted between the patients treated nonoperatively and operatively (P >0.05). There was a significant inverse correlation between the recovery rate and the degree of spinal cord compression as shown in MRI scans (P< 0.01). The presence of hematoma in MRI scans was associated with poor prognosis, as demonstrated by a significant difference of the recovery rate (P< 0.01) among the patients with normal intensity, edema and hematoma within the spinal cord. Conclusions. MRI scans provide an efficient assistance for decision- making and accurate prognostic information regarding neurological function, and therefore should routinely be performed within the early phase of acute central cord syndrome.

THE DIAGNOSIS OF MAGNETIC RESONANCE IMAGING FOR SPINAL CAVERNOUS ANGIOMAS

Objective To assess the characteristics of magnetic resonance imaging for spinal cavernous angiomas.Methods The examinations of plain scan and contrast enhanced scan of magnetic resonance were performed in three patients with spinal cavernous angiomas.Results The focus of two cases was located in thorax segment of the spinal cord and one in lower cervical segment.All focuses were single and the shape of spinal cord was normal or slightly thick. MRI characteristic of spinal cavernous angiomas was just like popcorn or mulberry with a jumbled gobbet signal. Low and short T 2 signal appeared around the focus. In all cases, there were no obvious contrast enhanced signal in 2 cases and one case with moderate contrast enhanced signal. The diameter of hemorrhage was smaller than that of the spinal cord.Conclusion MRI has higher sensitivity and specificity in the diagnosis of spinal cavernous angioma.

The Magnetic Resonance Image and Pathology of Spinal Cord Cavernous Hemangioma

Objective To investigate the characteristics of magnetic resonance image (MRI) of spinal cord cavernous hemangioma. Methods Six cases of spinal cord cavernous heman-gioma diagnosed by MRI and confirmed by pathology were reviewed. The characteristics of MRI were analyzed and correlated with pathological characteristics of spinal cord cavernous hemangioma. Results In 4 cases, the tumors were located in thoracic segment of the spinal cord and 2 in cervical cord. All lesions were solitary and the spinal cords were normal or a little thicker. The MRI showed that the images of focus were ball-like popcorn or mulberry with mixed signal,with short T2 signal around the focus. Under microscope, the hemangioma was composed of highly expanded blood sinusoids and its wall was thin and consisted of flat epithelial cells. There were some red blood cells in the cavity of the sinusoid and a little fibrous tissue in the diazoma between blood sinusoids. And also some fresh and old hemorrhages could be seen in the specimen. Conclusion MRI has high sensitivity and specificity in the diagnosis of spinal cavernous hemangioma.

Correlation of lumbar lateral recess stenosis in magnetic resonance imaging and clinical symptoms

AIM To assess the correlation of lateral recess stenosis(LRS) of lumbar segments L4/5 and L5/S1 and the Oswestry Disability Index(ODI).METHODS Nine hundred and twenty-seven patients with history of low back pain were included in this uncontrolled study.On magnetic resonance images(MRI) the lateral recesses(LR) at lumbar levels L4/5 and L5/S1 were evaluated and each nerve root was classified into a 4-point grading scale(Grade 0-3) as normal,not deviated,deviated or compressed.Patient symptoms and disability were assessed using ODI.The Spearman's rank correlation coefficient was used for statistical analysis(P < 0.05).RESULTS Approximately half of the LR revealed stenosis(grade 1-3;52% at level L4/5 and 42% at level L5/S1) with 2.2% and 1.9% respectively reveal a nerve root compression.The ODI score ranged from 0%-91.11% with an arithmetic mean of 34.06% ± 16.89%.We observed a very weak statistically significant positive correlation between ODI and LRS at lumbar levels L4/5 and L5/S1,each bilaterally(L4/5 left:rho < 0.105,P < 0.01;L4/5 right:rho < 0.111,P < 0.01;L5/S1 left:rho 0.128,P < 0.01;L5/S1 right:rho < 0.157,P < 0.001).CONCLUSION Although MRI is the standard imaging tool for diagnosing lumbar spinal stenosis,this study showed only a weak correlation of LRS on MRI and clinical findings.This can be attributed to a number of reasons outlined in this study,underlining that imaging findings alone are not sufficient to establish a reliable diagnosis for patients with LRS.

Skeletal muscle stiffness as measured by magnetic resonance elastography after chronic spinal cord injury:a cross-sectional pilot study

Skeletal muscle stiffness is altered after spinal cord injury(SCI).Assessing muscle stiffness is essential for rehabilitation and pharmaceutical interventions design after SCI.The study used magnetic resonance elastography to assess the changes in stiffness after chronic SCI compared to matched able-bodied controls and determine its association with muscle size,spasticity,and peak torque in persons with SCI.Previous studies examined the association between muscle stiffness and spasticity,however,we are unaware of other studies that examined the effects of muscle composition on stiffness after SCI.Ten participants(one female)with chronic SCI and eight(one female)matched able-bodied controls participated in this cross-sectional study.Magnetic resonance elastography was utilized to monitor stiffness derived from shear waves propagation.Modified Ashworth scale was used to evaluate spasticity scores in a blinded fashion.Peak isometric and isokinetic torques were measured using a biodex dynamometer.Stiffness values were non-significantly lower(12.5%;P=0.3)in the SCI group compared to able-bodied controls.Moreover,stiffness was positively related to vastus lateralis whole muscle cross-sectional area(CSA)(r2=0.64,P<0.005)and vastus lateralis absolute muscle CSA after accounting for intramuscular fat(r2=0.78,P<0.0007).Stiffness was also positively correlated to both isometric(r2=0.55-0.57,P<0.05)and isokinetic peak(r2=0.46-0.48,P<0.05)torques.Our results suggest that larger clinical trial is warranted to confirm the preliminary findings that muscle stiffness is altered after SCI compared to healthy controls.Stiffness appeared to be influenced by infiltration of intramuscular fat and modestly by the spasticity of the paralyzed muscles.The preliminary data indicated that the relationship between muscle stiffness and peak torque is not altered with changing the frequency of pulses or angular velocities.All study procedures were approved by the Institutional Review Board at the Hunter Holmes McGuire VA Medical Center,USA(IRB#:02314)on May 3,2017.

Magnetic resonance imaging findings of redundant nerve roots of the cauda equina

BACKGROUND Redundant nerve roots(RNRs)of the cauda equina are often a natural evolutionary part of lumbar spinal canal stenosis secondary to degenerative processes characterized by elongated,enlarged,and tortuous nerve roots in the superior and/or inferior of the stenotic segment.Although magnetic resonance imaging(MRI)findings have been defined more frequently in recent years,this condition has been relatively under-recognized in radiological practice.In this study,lumbar MRI findings of RNRs of the cauda equina were evaluated in spinal stenosis patients.AIM To evaluate RNRs of the cauda equina in spinal stenosis patients.METHODS One-hundred and thirty-one patients who underwent lumbar MRI and were found to have spinal stenosis between March 2010 and February 2019 were included in the study.On axial T2-weighted images(T2WI),the cross-sectional area(CSA)of the dural sac was measured at L2-3,L3-4,L4-5,and L5-S1 levels in the axial plane.CSA levels below 100 mm^2 were considered stenosis.Elongation,expansion,and tortuosity in cauda equina fibers in the superior and/or inferior of the stenotic segment were evaluated as RNRs.The patients were divided into two groups:Those with RNRs and those without RNRs.The CSA cut-off value resulting in RNRs of cauda equina was calculated.Relative length(RL)of RNRs was calculated by dividing the length of RNRs at mid-sagittal T2WI by the height of the vertebral body superior to the stenosis level.The associations of CSA leading to RNRs with RL,disc herniation type,and spondylolisthesis were evaluated.RESULTS Fifty-five patients(42%)with spinal stenosis had RNRs of the cauda equina.The average CSA was 40.99±12.76 mm^2 in patients with RNRs of the cauda equina and 66.83±19.32 mm^2 in patients without RNRs.A significant difference was found between the two groups for CSA values(P<0.001).Using a cut-off value of 55.22 mm^2 for RNRs of the cauda equina,sensitivity,specificity,positive predictive value(PPV),and negative predictive value(NPV)values of 96.4%,96.1%,89.4%,and 98.7%were obtained,respectively.RL was 3.39±1.31(range:0.93-6.01).When the extension of RNRs into the superior and/or inferior of the spinal canal stenosis level was evaluated,it was superior in 54.5%,both superior and inferior in 32.8%,and inferior in 12.7%.At stenosis levels leading to RNRs of the cauda equina,29 disc herniations with soft margins and 26 with sharp margins were detected.Disc herniation type and spondylolisthesis had no significant relationship with RL or CSA of the dural sac with stenotic levels(P>0.05).As the CSA of the dural sac decreased,the incidence of RNRs observed at the superior of the stenosis level increased(P<0.001).CONCLUSION RNRs of the cauda equina are frequently observed in patients with spinal stenosis.When the CSA of the dural sac is<55 mm^2,lumbar MRIs should be carefully examined for this condition.

The imaging analysis of magnetic resonance myelography in disease of the lumbosacral nerve roots

AIM：To illustrate the magnetic resonce(MR) myelography features in the disease of lumbosacral nerve roots.METHODS:MR myelography using heavily T2 weighted spin-echo imaging with fat supression was performed in 75 cases with chronic pain of waist on a Siemens Magneton Impect 1.0 TMR unit.Maximum intensity projection(MIP) was used for image reconstruction.RESULTS:The thecal maugins,nerve roots and nerve root sheaths were well demonstrated on MR myelography image.In 75 patients with chronic of waist,nerve root disease was found in 11 cases.6nerve root abnormality (8%),2perineural cyst(3%),3 neurofibroma(4%) had their own MR myelography features.CONCLUSION:MR myelography can show the morphologic and structural change of lumbosacral nerve roots.In MR myelography image,disease of lumbosacral nerve roots has a characteristic finding.MR myelography in very useful in diagnosis of nerve-root disease.

Spontaneous conus infarction with"snake-eye appearance"on magnetic resonance imaging:A case report and literature review

BACKGROUND Infarction of the conus medullaris is a rare form of spinal cord infarction.The first symptom is usually acute non-characteristic lumbar pain,followed by lower limb pain,saddle numbness,fecal incontinence,and sexual dysfunction.Spontaneous conus infarction with"snake-eye appearance"on magnetic resonance imaging has rarely been reported.CASE SUMMARY We report a 79-year-old male patient with spontaneous conus infarction who had acute lower extremity pain and dysuria as the first symptoms.He did not have any recent history of aortic surgery and trauma.Magnetic resonance imaging revealed a rare"snake-eye appearance."In addition,we reviewed the literature on 23 similar cases and summarized the clinical features and magnetic resonance manifestations of common diseases related to the"snake-eye sign"to explore the etiology,imaging findings,and prognosis of spontaneous conus infarction.CONCLUSION We conclude that acute onset of conus medullaris syndrome combined with"snake-eye appearance"should be strongly suspected as conus medullaris infarction caused by anterior spinal artery ischemia.This special imaging manifestation is helpful in the early diagnosis and treatment of conus infarction.

Magnetic Resonance Imaging of Retropharyngeal Lymphadenopathy in Nasopharyngeal Carcinoma

OBJECTIVE The aim of our study was to document the patterns of RLN spread by using MRI. METHODS The MR images of 294 patients with newly diagnosed NPC were reviewed retrospectively. Criteria for metastatic lymph nodes included： shortest axial diameter, nodal necrosis, extracapsular spread, and a contrast enhancing rim. RESULTS RLN involvement was detected in 190 （64.6%） patients. A significantly higher incidence of metastatic RLNs was observed in patients with involvement of the oropharynx, nasal cavity, pre-styloid parapharyngeal space, post-styloid parapharyngeal space, levator muscle of the velum palatini, and tensor muscle of the velum palatine. Patients with level Ⅱ,Ⅲ, and Ⅴ node involvement also had a higher incidence of metastatic RLNs. Of the 231 patients who had metastatic RLNs or cervical lymph nodes, 43 （18.6%） had only metastatic RLNs, 41 （17.7%） had only metastatic cervical lymph nodes, and 147 （63.6%） exhibited an involvement of both the RLNs and cervical lymph nodes. The difference between the incidence of RLN involvements （82.3%） and the incidence of cervical lymph node involvement （81.4%） was very small. CONCLUSION Metastatic RLNs are significantly associated with early stage primary tumor involvement and supper cervical lymph node metastasis in NPC.

Specific Patterns of Spinal Metabolite Ratio Underlying a-Me-5-HTevoked Pruritus Compared with Compound 48/80 Based on Proton Nuclear Magnetic Resonance Spectroscopy

Summary:Mechanisms of pruritus are implicated in the dysregulation of the metabolites in the spinal cord.We investigated pruritus behavioral testing in three groups of young adult male C57B1/6 mice,including one group treated with normal saline,while the other groups intradermally injected with a-Me-5-HT(histamine-independent pruritogen),compound 48/80(histaminedependent pruritogen)at the nape skin of the neck,respectively.Proton nuclear magnetic resonance spectroscopy(MRS)was used to compare spinal metabolites from the vertebral cervical among three groups,and to study the association of spinal metabolite ratio and pruritus intensity.The MRS-measured N-acetylaspartate-to-myoinositol ratio(NAA/Ins)was significantly correlated with the number of scratches between normal saline group and 48/80 group or a-Me-5-HT group(both P<0.0001),indicating that NAA/Ins may be a robust surrogate marker of histamine-independent/dependent pruritogen.There was significant difference in Glu/Ins between normal saline group and 48/80 group(P=0.017),indicating that Glu/Ins may be a surrogate marker of histamine-dependent pruritogen,while GABA/Ins was highly significantly different between normal saline group and a-Me-5-HT group(P=0.008),suggesting that GABA/Ins may be a surrogate marker of histamineindependent pruritogen.MRS may reflect the extent of pruritus intensity elicited by a-Me-5-HT and compound 48/80 with sensitivity similar to the number of scratches,and above potential markers need to be further validated in pre-clinical and clinical treatment trials.