The Value Of MR Three Dimensional Double Inversion Recovery Sequence In The Diagnosis Of NMO

BackgroundThe neuromyelitis optica(NMO)is an acute or subacute lesion of demyelination that involving the optic nerve and spinal cord,myelin damaged or loss to the main features of the disease,demyelinating is prominent features in the pathological process..For a long time,the NMO has been recognized as one of a subtype of multiple sclerosis MS.It is commonly happened in female patients in Asia,including China,with high recurrence rate and poor prognosis.It is difficult to identify the two lesions at the early stage,but the identification seems easier at the late stage.With the development of the radiological technology,especially for the development of post-processing sequence of magnetic resonance,researchers have found that there were significant differences for characteristics of lesions between NMO and MS.However,because the treatment schedules of the two diseases are different,therefore,it is of great importance to identify the disease earlier.In China,the relapsing NMO is common.The clinical manifestations of MS and NMO is similar to that of the characteristics of the conventional imaging,and clinical treatment is obviously different.Therefore,a superior magnetic resonance technique is necessary for diagnosis of NMO and MS.At present how to combine the various functions of MR and conventional MRI imaging showed demyelinating lesions and occult injury,and successfully identify two kinds of diseases have become the focusof further study.Three dimensional inversion recovery sequence(3D-DIR)significantly improved the signal contrast between different tissues by applying two reversal pulses,and the imaging of gray matter lesions was more clear.The three-dimensional double-inversion recovery(3D-DIR)imaging technique is a novel magnetic resonance method and has not yet been popularized in clinical practice.Compared with conventional MR imaging,this sequence is more sensitive to the gray matter lesions of the brain and spinal cord.It has extensive application value in the differential diagnosis of many kinds of central nervous system diseases,therapeutic effect evaluation,patient monitoring and follow up,etc.In this study,the principle of the imaging sequence and its application in the application of optic nerve and spinal cord were studied.The 3D-DIR is implemented using a turbo spinecho sequence with variable flip angle,significantly improves the signal contrast of different tissues and clearly show the gray matter lesions in clinical.In recent years,the 3D-DIR sequence has been improved and developed,combined with the 3D data acquisition technology,the image spatial resolution and contrast resolution are greatly improved,become a new method for detecting gray matter lesions of central nervous system diseases.In recent years,3D-DIR has been gradually applied in the diagnosis of epilepsy,multiple sclerosis and other diseases with better effect.This study sought to assess the value of 3D-DIR in the diagnosis of NMO.In order to further differential diagnosis,we analyzed the clinical data and MR imaging of NMO and MS.PART I:THE DIGNOSTIC VALUE OF 3D-DIR IN DETECTION OF NMO Objective:We analyzed the advantages of 3D-DIR sequence by analyzing the 3D-DIR sequence and the normal sequence of the optic nerve and spinal cord inflammation,and to study whether there was a great value of application in the diagnosis of NMO.Methods:36 NMO patients from October 2013 to 2015 10 month in our hospital treatment of complete information were selected.The diagnosis according to the diagnostic criteria of Wingerchuck et al which was revised in 2015.A Siemens MAGNETOM Skyra 3.0T superconducting scanner and 8-channel head coil were used to perform the routine MR examination.Fast spin echo(TSE)T2WI,fluid-attenuated inversion recovery(FLAIR)sequence and 3D-DIR sequence were examined respectively.Parameters of the 3D-DIR sequence included(TR 7500 msec,TE 308 msec,T1 3000 msec;matrix 190×192;visual field of FOV 256×256 mm;128 layers;and thickness of 1.3 mm),two reversal pulses,TI1(time from the first 180°reverse pulse to 90° drive pulse)3400 mesc,and parameters of TI2(time from the second 180° reverse pulse to 90° drive pulse)325 msec.subsequently,T2W TSE sequence(TR 5000 msec,TE 87 msec;matrix 256×256;FOV 256×256 mm,thickness of 4 mm)scanning was performed.Two deputy chief physician radiologist independent analysis of the image data to determine the origin of brain lesions with or without,disagree together to reach a consensus.T2WI,T2FLAIR,3D-DIR sequence were recorded in the brain distribution and number,comparison of the three sequences of NMO in patients with brain and spinal cord lesion signal characteristics,display range of lesions and lesion detection rate,P<0.05 was statistically significant.Image features of T2WI,T2FLAIR,3D-DIR in the optic nerve and spinal cord lesions were analyzed.Results:1.36 cases of NMO patients were performed with magnetic resonance imaging of the brain and spinal cord,brain lesions in 20 patients with a total of 249 cases of lesions.The combination of gray and white matter in 6 cases,12 cases of ependyma,cortex(perforator surface)in 4 cases,in the white matter(away from the perforating vessels)in 2 cases,the four ventricle(dorsal brainstem)in 9 cases,other 2 cases of atypical sites(not included in this study).T2WI,T2FLAIR,DIR sequences were detected in the above parts of the statistics are as follows:To detect the gray matter with portions of 43,48,50,detection of subependymal lesions were 56,80,106,detection of cortical lesions were 15,23,32,detection of white matter lesions(away from the perforating vessels)were 23,25,26 and detect the floor of the four ventricle(dorsal brainstem lesions)were 28,30,35.The T2WI,T2FLAIR was respectively compared with DIR sequence,We found that the 3D-DIR sequences were significantly higher than those of the first two,and the difference was statistically significant(P<0.05)in the total lesions of the brain,in the lower chamber and in the cortical lesions.All lesions in the brain showed a relatively high signal in the DIR sequence,while the other two sequences showed slightly higher signal intensity,and the DIR showed a sharper border(see Figure 1 and Figure 2).2.All of the 36 patients had spinal cord lesions,and the lesions were more than 3 vertebral bodies.Among them,11 cases were involved in the middle segment,12 cases were involved in the middle and posterior segments,and 1 cases showed only the visual cross.The lesions occurred in 15 cases of cervical cord,8 cases of thoracic spinal cord,11 cases of cervical thoracic spinal cord,2 cases of cervical vertebra and lumbar spinal cord.From the NMO images of patients with spinal cord lesions visible,compared with the T2WI signal,DIR images showed higher signal of spinal cord lesions,Axial images showed a central distribution in 31 cases(86%),involving the central part of the gray matter and white matter,Transverse(see figure 3A),eccentric distribution of 5 cases(14%).DIR images can show the spinal cord lesions that can not be displayed by conventional MRI(Figure 3 and Figure 7).3.36 cases of patients with optic nerve injury in 24 cases,the lesions were located at the middle and posterior segment,11 cases involving middle patients,12 cases of middle and posterior segment were involved,and 1 cases showed only involved the optic chiasma.3D-DIR of optic nerve and optic image showed that either axial or coronal lesions,the signal intensity is more obvious than that of T2WI and T2FLAIR(see Figure 4 and figure 5).Conclusion1.3D-DIR sequence compared with T2WI sequence and T2FLAIR,it can significantly improve the detection rate of NMO in patients with brain lesions,especially total brain lesions,subependymal and cortical lesions,the difference was statistically significant,indicating that 3D-DIR sequence has great application value in the diagnosis of neuromyelitis optica.2.3D-DIR sequence can be used to verify the small lesions of the spinal cord,and to improve the detection of lesions.Compared with the T2WI signal,DIR signal can be more obvious display of the spinal cord,86%cases involving the central part of the gray matter and white matter.3.3D-DIR of optic nerve and optic image showed that either axial or coronal lesions,the signal intensity is more obvious than that of T2WI and T2FLAIRPART Ⅱ:CLINICAL CHARACTERISTICS AND TRADITIONAL MRI IMAGES OF NMO AND MSObjective:In order to further explore the clinical data of NMO and MRI and the similarities and differences of MS image and DIR image.In this part,36 NMO patients and 68 MS patients of the basic clinical data and MRI images and 3D-DIR images were analyzed retrospectively,and the lesions were analyzed to provide the basis for the diagnosis of NMO disease effectively.Methods:(1)We collected data from patients with NMO or MS who registed in our hospital From October 2013 to October 2015,the clinical features including ages,gender,disease history and clinical symptoms were analyzed and compared between the two groups.NMO diagnostic criteria according to the 2015 diagnostic criteria that Wingerchuck revised,MS patient diagnostic criteria in accordance with the 2010 MCdonald diagnostic criteria[24].(2)The cerebrospinal fluid(CSF)were punctured from the lumbar of the patients and tests.(3)The superconducting scanner(Siemens MAGNETOM Skyra 3.0T)was used in our study for identification of the lesions of head and spinal cord.Results:1.The proportion of male and female patients with NMO and MS were 1:5 and 1:2.09.There were 26 patients with NMO(72.22%)and 49 patients with MS(72.06%)before the onset of any abnormal symptoms,there was no statistically significant difference between the two groups(P = 0.389).2.In 36 NMO patients,20 cases were found brain lesions,lesions located in the periventricular region,distributed in the medulla,ependyma,thalamus,surrounding area of cerebral white matter,three ventricle,periaqueductal,pons,diencephalon(AQP4 protein high expression of CSF.),A total of 30 patients(44.12%)with simple brain involvement in MS patients,19 patients(27.94%)with simple spinal cord involvement O,and 19 cases(27.94%)were involved in the brain and spinal cord.And 49 cases of MS patients with brain lesions were mainly occurred in the lateral ventricles(n = 36)and the corpus callosum(n = 17),and the rest were distributed in the brain stem,cortex and other parts of the brain.MS patients with brain lesions were round or oval,spots or patches.3.In 36 NMO patients,24 cases(66.67%)developed optic nerve damage,30 MS patients(44.11%)showed optic nerve damage,Spinal cord injury is mainly manifested in numbness of limbs,difficulty in walking and difficulty in defecation.The two symptoms of NMO were 45.45%and 45.45%respectively.The two symptoms were 50%and 37.50%,respectively(see Table 2).4.Spinal cord lesions were found in 36 patients with NMO.The lesion length was larger than 3 vertebral bodies.The lesions occurred in 15 cases of cervical cord,8 cases of thoracic spinal cord,11 cases of cervical thoracic spinal cord and 2 cases of cervical spinal cord lesions.Axial images showed a central distribution in 31 cases(86%),and 5 cases(14%).There were 38 cases of spinal cord involvement in MS patients,including 19 cases(27.94%)with simple spinal cord involvement,19 cases(27.94%)with brain and spinal cord.The morphology of spinal cord lesions was mainly centered in the center of NMO patients,and the longitudinal fusion was presented.In patients with MS,the lesions were mainly round and patchy,and were distributed in the periphery(see Figure 2 and figure 3).Compared with the T2WI signal,DIR images showed a higher signal of spinal cord lesions,and the lesions were mainly distributed in the cervical and thoracic spinal cord in two patients.5.The positive rate of AQP4 antibody was much more in NMO patients(83.33%)than that in MS patients(2.94%)(P<0.05).Conclusion:1.NMO occurs mostly in young or middle-aged people.Female patients are more than men.2.Most of the patients with MS and NMO had no abnormal symptoms before the onset of the disease.And a few patients before the onset of the disease may be the cause of the disease,mainly for the upper respiratory tract infections,spinal inflammation,atherosclerosis,cervical spondylosis and fatigue,etc.3.The clinical features of NMO and MS,showed decreased visual acuity,body numbness,walking difficulties and defecation difficulties.4.Magnetic resonance imaging showed that NMO patients with spinal lesions were significantly more than MS patients.In the former,the morphology of the spinal cord lesions was mainly centered,and it showed a longitudinal fusion.The latter lesions were oval,and rely on the surrounding asymmetric distribution.5.The brain lesions in MS patients were more than those in NMO patients.NMO in the patients with brain lesions located in the periventricular,medulla,ependyma,thalamus,dorsal area around the cerebral white matter,three ventricle,periaqueductal,pons,diencephalon and brain lesions;MS patients mainly occurs at the lateral ventricle and corpus callosum were round,patchy and patchy.6.The imaging features of NMO and MS patients were different,So when the patient visits or follow up should scan the brain and spinal cord,,and the differential diagnosis is of great value.