Study Of Multisequence And Quantitative Magnetic Resonance Neurography And Its Applications In Peripheral Polyneuropathy

Part Ⅰ Multisequence magnetic resonance neurography of peripheral nerves: Establishment and validation of brachial and lumbosacral plexi measurements in healthy subjects.Objective: To provide normal reference values of quantitative multi-parameters for brachial and lumbosacral plexi on multisequence magnetic resonance neurography(MRN).In addition,the parameter variations between the left and right sides,different genders and ages are also evaluated.Material and Methods: We evaluated 163 healthy subjects(mean age,38 years old;age range,18-65 years old)using multisequence MRN,randomized into three groups: brachial plexus,lumbosacral(LS)plexus and diffusion tensor imaging(DTI)groups.The MR sequences were included turbo inversion recovery magnitude,volumetric interpolated breath-hold examination and sampling perfection with application-optimized contrasts using different flip angle evolution in brachial and LS plexi groups.Based echo planar imaging DTI and proton density weighted image sequences were included in DTI group.Nerve diameter,nerve-to-muscle T2 signal intensity ratio(n T2),contrast-enhanced ratio(CR),fractional anisotropy(FA)and apparent diffusion coefficient(ADC)were determined in both brachial(C5-C8)and LS(L4-S1)plexi,and tractography was performed.The subjects were divided into two age groups: the young group and the elder group with the age range at 18-40 years and 40+ years,respectively.Statistical assessments included contingency table approach,the Kruskal-Wallis H tests,the samples paired t test,independent samples t test,wilcoxon signed-rank test and wilcoxon rank test.Pearson(or Spearman rank)correlation test was used to detect the correlations.Intraclass correlation coefficients(ICC)were obtained for interreader and intrareader reliability.P < 0.05 was considered statistically significant.Results: There were no significant differences in demographics(gender and age)among the three groups.The ICC ranged from 0.703 to 0.891 for intra-reader and inter-reader.There was no significant difference between genders in BMI(P = 0.81).There was no statistically significant correlation between the diameters and BMI(P >0.05).There were no statistical differences between the left and right sides of each parameter(P >0.05).The sizes of the C7 and L4-S1,sciatic,femoral nerve roots were larger in men than female group(all P < 0.05).The n T2 in brachial and LS plexus and CR values in LS plexus were significantly higher in the elder than in the younger group(all P <0.05).The diameter at S1 nerve root was significantly smaller in the elder group(P <0.05).Pearson correlation showed a weak negative correlation between FA and age at C8 nerve root(r=-0.25,P = 0.011).A negative weak or moderate correlation was observed between FA and ADC at nerve roots or ganglions in plexus,respectively.The FA of the ganglia at the brachial and LS plexi were significantly lower than those of the corresponding nerve roots,but the ADC were significantly higher(P <0.05).Conclusion: Multisequence MRN have good feasibly and repeatability in brachial and LS plexi.We have provided multi-parameter normative data of nerve roots in plexi and as well as any differences related to different sides,genders and ages.Part Ⅱ The use of magnetic resonance neurography for evaluating distribution and patterns of chronic inflammatory demyelinating polyneuropathyPurpose: To evaluate the distribution and characteristics of peripheral nerves abnormalities in chronic inflammatory demyelinating polyneuropathy(CIDP)using MR neurography(MRN)with large field of view and MRN’s diagnosis efficiency.Methods: 31 CIDP patients and on 30 controls were underwent MR scans on a 3.0T scanner.Three-dimensional sampling perfection with application-optimized contrasts using different flip-angle evolutions(3D SPACE)and T1/2-weighted turbo spin-echo sequences were performed for neurography of the brachial and lumbosacral(LS)plexus and the cauda equina,respectively.Two experienced radiologists assessed the images for nerve hypertrophy type(type I: uniform hypertrophy,type II: multifocal fusiform hypertrophy).The diffuse enlargement and/or enhancement of the cauda equina were recorded.The nerve diameter of the brachial(C5-C8 nerve roots)and LS(L4-S1 nerve roots,sciatic and femoral nerves)were measured.Non-normally distributed data were expressed as median and quartiles.Non-parametrical Mann-Whitney U tests,Chi-square test,Intraclass correlation coefficient(ICC)and receiver operating characteristic(ROC)analyses were used.Results: Nerve hypertrophy associated with hyperintensity was observed in the brachial plexus of 19/31(61.3%),in the lumbosacral plexus of 25/31(80.6%)CIDP patients,and in none of the controls.Bilateral extracranial vagus nerves(n=11,35.5%),trigeminal nerve branches(n=10,32.3%)and intercostal nerves(n=10,32.3%)were found to be uniform or to be exhibiting multifocal fusiform hypertrophy.Enlarged and/or enhanced caudae equinae were found in 3/31(9.7%)and 13/31(41.9%)patients,respectively.The hypertrophy results were as follows: uniform hypertrophy(type I: n=17/31 and n=21/31 in the brachial and lumbosacral plexi,respectively)and multifocal fusiform hypertrophy(type II,n=2/31 and n=4/31,respectively).The diameter of the C5-C8,L4-S1,and sciatic and femoral nerve roots were significantly larger in patients with CIDP than in the controls(P <0.001).The largest AUC was the diameter of the L5 nerve root in the lumbosacral plexus,corresponding cut-off value,sensitivity,specificity and the area under the curve are 7.06,86.4%,97.4% and 0.964,respectively.ICC value were 0.87–0.94 for intrareader and 0.83-0.91 for interreader in the CIDP and control groups.Conclusion: MR neurography is useful for the assessment of distribution and characteristics in CIDP.Compared to other regions,lumbosacral plexus neurography is more sensitive to the diagnosis of CIDP.Part Ⅲ Multisequence quantitative magnetic resonance neurography of brachial and lumbosacral plexus in chronic inflammatory demyelinating polyneuropathy and its differential diagnosisObjectives: To evaluate the differential diagnostic efficiency and brachial and lumbosacral(LS)plexi abnormalities via quantitatively multisequence magnetic resonance neurography(MRN)for chronic inflammatory demyelinating polyneuropathy(CIDP).Materials and Methods: Brachial and LS plexi of 37 patients with CIDP and 37 age-matched patient controls were examined with multisequence MRN,including turbo inversion recovery magnitude,volumetric interpolated breath-hold examination,three-dimensional sampling perfection with application-optimized contrasts using different flip angle evolution(3D SPACE)and diffusion tensor imaging(DTI)sequences.Nerve diameter,nerve-to-muscle T2 signal intensity ratio(n T2),contrast-enhanced ratio(CR),fractional anisotropy(FA)and apparent diffusion coefficient(ADC)were determined in both brachial(C5-C8 nerve roots)and LS(L4-S1 nerve roots)plexi,and diffusion tensor tractography(flip angle of 30 degrees and an FA threshold of 0.10)was performed.Statistical analysis included wilcoxon signed-rank test,receiver operating characteristic(ROC)analysis,intraclass correlation coefficient(ICC)and spearman rank correlation.Results: A total of 74 patients(148 plexi and 1036 nerves)were studied.There has no significant difference in clinical characteristics between patients with CIDP and patient controls(P >0.05).The nerve diameters of the C5-C8,L4-S1 nerve roots,sciatic and femoral nerves were larger in patients with CIDP than in controls(P < 0.001).The CR,n T2 and ADC value of the both brachial and LS plexi were significantly higher in the CIDP than in controls(P < 0.001),while the FA value were lower than controls(P < 0.001).In single-parameter model,FA value had the largest AUC(0.807)using cutoff value of 0.355,with the highest sensitivity(94.1%)in the LS plexus.The combined two-parameter model showing the largest AUC(0.892)was the combination of FA and CR values with the sensitivity(83.8%)and specificity(80.9%)in the LS plexus.There were moderate negative correlations between FA and ADC in the CIDP and controls(|r’s| range: 0.403-0.477,P< 0.01).CR had weak correlations with FA and n T2 value(|r’s| range: 0.179-0.252,P< 0.01),and no significant correlation with other parameters.n T2 had a moderate negative correlation with ADC in CIDP patients(r’s =0.495,P <0.01),while a weak correlation in controls(r’s =0.284,P <0.01).There have weak correlations in the rest of the FA,diameters,n T2 and ADC values(|r’s| range: 0.216-0.390,P< 0.01).There were good inter-and intra-observer consistencies for each parameter assessed in the plexi(ICC range: 0.754-0.892).Conclusions: Multisequence quantitative MRN has high differential diagnostic accuracy in the brachial and LS plexi for the CIDP.3D SPACE combined with DTI and contrast enhancement serve as recommended composite protocol in demyelinating polyneuropathy.Part Ⅳ Serial electrophysiological and clinical study of peripheral polyneuropathy,and correlation with the multisequence quantitative magnetic resonance neurographyObjectives: To compare electrophysiological features in patients with chronic inflammatory demyelinating polyneuropathy(CIDP),hereditary motor and sensory neuropathies(HMSN)and Guillain-Barre syndrome(GBS)for guiding differential diagnosis.To evaluate the correlation between quantitative magnetic resonance neurography(MRN)and the clinical features and electromyography.Materials and Methods: A total of 102 patients with peripheral polyneuropathy were enrolled,including 41 patients with CIDP,30 patients with HMSN,and 31 patients with GBS.Electrophysiological examinations were performed on the median,ulnar,peroneal and tibial nerves of all patients.The patients whose response waveform can be elicited in all nerves were defined as group A,and those without response in one or more nerves as group B.The Inflammatory Rasch-built Overall Disability Scale(I-RODS),CIDP disease activity status(CADS)and the UK Medical Research Council(MRC)were used to evaluate the illness activity and severity of patients.Brachial and lumbosacral(LS)plexi of the patients with CIDP were examined with multisequence MRN.Nerve diameter,nerve-to-muscle T2 signal intensity ratio(n T2),contrast-enhanced ratio(CR),fractional anisotropy(FA)and apparent diffusion coefficient(ADC)were determined in both brachial(C5-C8 nerve roots)and LS(L4-S1 nerve roots)plexi.Then,the average value of each parameter on the ipsilateral side of the plexus were taken.Statistical analysis included Crosstabs,Kruskal-Wallis H and Mann-Whitney U tests.Pearson and Spearman rank correlation analysis were used.P <0.05 were considered significant difference.Results: A total of 492 motor and 505 sensory nerves in limbs were examined.The unextracted rate of lower limb nerves in CIDP was higher than that of upper limbs(P <0.001),and the unextracted rate of sensory nerves was higher than that of motor nerves(P <0.05).The MCV,SCV and CMAP,SNAP amplitudes in group B were significantly lower than those in group A,and DML and PL were longer than in group A(P <0.05).The unextracted rates of motor conduction in the CIDP were higher than GBS(P <0.01),but with no significant differences from HMSN(P >0.05).Quantitative analysis showed that MCV was lower and DML was longer in the HSMN than CIDP(P <0.05).The GBS had higher MCV than the CIDP,but the CMAP amplitude was lower(P <0.05).The unextracted rates of sensory conduction in the CIDP were higher than HMSN(P <0.01),but with no significant differences from the GBS(P> 0.05).Quantitative analysis showed that the SCV and SNAP amplitudes of the HSMN were lower than the CIDP(P <0.05).The SCV and SNAP amplitudes of the superficial peroneal nerve in the CIDP were lower than the GBS(P <0.05).MCV and DML both have moderate correlations among with diameter,n T2,FA,and ADC values of nerve root(| r | range: 0.4-0.7,P <0.05).PL and SCV have moderate correlations between CR(| r | range: 0.4-0.7,P <0.05).There are moderate positive correlations between SNAP and ADC(r= 0.548,P <0.05).FA have moderate negative correlations with disease course(r =-0.406)and CSF protein(r =-0.441),and a weak positive correlation between ADC and CSF protein(r = 0.356)(P <0.05).A moderate positive correlation between CR and CADS(r’s = 0.570,P = 0.003).There were positive correlations between FA and MRC scores of the extremities(r’s range: 0.410-0.493,P <0.05).No significant correlation between I-RODS score and MRN parameters(P> 0.05).Conclusion: The neuroelectrophysiology of the limb’s peripheral nerves have showed demyelination and secondary axonal injury in the patients with CIDP,HSMN and GBS,but still exist some differences.There are good correlations between multi-parameters MRN and the electrophysiological parameters related with myelin sheaths,as well as CSF protein,activity and severity of disease,which could provide effective MR biomarkers.