Differential diagnosis of white matter diseases in the tropics: An overview

In hospitals in the tropics, the availability of magnetic resonance imaging (MRI) facilities in urban areas and especially in teaching institutions have resulted in white matter diseases being frequently reported in a variety of clinical settings. Unlike the west where multiple sclerosis (MS) is the commonest white matter disease encountered, in the tropics, there are myriad causes for the same. Infectious and post infectious disorders probably account for the vast majority of these diseases. Human immunodeficiency virus (HIV) infection tops the list of infective conditions. Central nervous system (CNS) tuberculosis occasionally presents with patchy parenchymal lesions unaccompanied by meningeal involvement. Human T cell leukemia virus (HTLV) infection and cystic inflammatory lesions such as neurocysticercosis are important causes to be considered in the differential diagnosis. Diagnosing post infectious demyelinating disorders is equally challenging since more than a third of cases seen in the tropics do not present with history of past infection or vaccinations. Metabolic and deficiency disorders such as Wernicke''s encephalopathy, osmotic demyelinating syndrome associated with extra pontine lesions and Vitamin B12 deficiency states can occassionaly cause confusion in diagnosis. This review considers a few important disorders which manifest with white matter changes on MRI and create diagnostic difficulties in a population in the tropics.     

Multiple gliomas. Illustrative cases of 4 different presentations

Multiple gliomas are uncommon and may be classified according to: a) the time of presentation in early (at diagnosis) or late (during treatment); b) the characteristics of computed tomography or magnetic resonance imaging (CT/MRI) in multifocal (with evidence of spread) and multicentric (without evidence of spread). From 212 patients with histopathologic diagnosis of glioma evaluated from March/90 to September/99, 15 (7%) had multiple lesions. We describe 4 patients: early multicentric, late multicentric, early multifocal and late multifocal, with emphasis on characteristics of CT/MRI and possible differential diagnosis. The differential diagnosis of multiple lesions in the central nervous system includes mainly infectious/inflammatory diseases and metastasis, however multiple gliomas should always be considered, even in patients with known systemic cancer, as described by others. Considering that CT/MRI features are not definite, the diagnosis should always be confirmed by histopathologic examination.     

原发性中枢神经系统淋巴瘤(附3例报道)

目的原发性中枢神经系统淋巴瘤很少见,本文报道3例原发性中枢神经系统淋巴瘤,以提高人们对本病的认识.方法回顾性分析3例患者的临床资料.结果2例患者临床以半身无力为主要症状,头颅CT、MRI检查示占位性病变,其中1例多发(3个病灶),1例单发.分别经脑活检和手术病理证实为淋巴瘤.1例患者首发症状为双侧视力障碍伴双下肢无力,经头颅CT、MRI检查未见异常,经脑脊液细胞学检查及免疫分型,诊断为淋巴细胞瘤.结论中枢神经系统淋巴瘤,特别是侵犯脑膜而非脑实质时,影像学检查有时也很难确诊,脑脊液细胞学检查为这些患者提供了可靠的临床诊断方法.     

Central vein sign and paramagnetic rim sign: From radiologically isolated syndrome to multiple sclerosis

The widespread use of magnetic resonance imaging (MRI) has led to an increase in incidental findings in the central nervous system. Radiologically isolated syndrome (RIS) is a condition where imaging reveals lesions suggestive of demyelinating disease without any clinical episodes consistent with multiple sclerosis (MS). The prognosis for RIS patients is uncertain, with some remaining asymptomatic while others progress to MS. Several risk factors for disease progression have been identified, including male sex, younger age at diagnosis, and spinal cord lesions. This article reviews two promising biomarkers, the central vein sign (CVS) and the paramagnetic rim sign (PRS), and their potential role in the diagnosis and prognosis of MS and RIS. Both CVS and PRS have been shown to be accurate diagnostic markers in MS, with high sensitivity and specificity, and have been useful in distinguishing MS from other disorders. Further research is needed to validate these findings and determine the clinical utility of these biomarkers in routine practice.     

Role of MRI in the pediatric central nervous system disorders

Recent rapid development of the MRI system has enabled us to diagnose precisely the disorders of the central nervous system (CNS) also in neonates and young children. Because of a long studying time, the use of oral chloral hydrate or other alternative drugs for sedation, such as secobarbital and meperidine, is necessary for young children under 6 years of age. The advantages of MRI are the optional plane imaging, a high contrast resolution, and the artifact-free imaging from the surrounding bones and air. MRI can detect myelination disorders and the lesions in the posterior fossa, the middle fossa, and the spinal canal. These abnormalities are difficult to depict with conventional X-ray CT scanning. MRI is useful also for the survey of various congenital anomalies of the brain and the spine. Furthermore, it is sensitive enough to detect the CNS blood flow and the cerebrospinal fluid (CSF) flow. Arteriovenous malformation, moyamoya disease, and sinus thrombosis are diagnosed by MRI without using contrast media, CSF flow void phenomena in the aqueduct and the Monro's foramina are indexes of the CSF pathway obstruction and of normal pressure hydrocephalus.     

FDG-PET SUV can distinguish between spinal sarcoidosis and myelopathy with canal stenosis

Spinal cord sarcoidosis is a rare manifestation of sarcoidosis. Magnetic resonance imaging (MRI) of spinal cord sarcoidosis sometimes resembles that of the non-inflammatory spinal cord lesion. ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) is an effective method to detect both systemic and central nervous system lesions in sarcoidosis. This study compared the standard uptake value (SUV) of FDG-PET between spinal cord sarcoidosis and non-inflammatory spinal cord lesions. We retrospectively reviewed the records of patients who underwent both spinal MRI and FDG-PET scans. We used SUV to evaluate the FDG-PET uptake of the lesion. The region of interest was the center of high-intensity areas on T2-weighted MR images. We included three patients with spinal cord sarcoidosis, five with myelomalacia caused by cervical spondylosis or ossification of the posterior longitudinal ligament, one with spinal cord edema associated with cervical spondylosis, and one with spinal cord edema associated with dural arteriovenous fistula. The spinal cord sarcoidosis group had a significantly higher SUV (mean 4.38, range 3.30–4.93) than patients with the other diseases (mean 1.87, range 1.42–2.74). The SUV of FDG-PET thus may be able to distinguish spinal cord sarcoidosis from other non-inflammatory lesions. FDG-PET can play an important role in the diagnosis of spinal cord sarcoidosis because the gadolinium enhancement in MRI is sometimes seen in spondylotic myelopathy or vascular malformation. FDG-PET is informative for the accurate diagnosis of spinal cord sarcoidosis and may enable clinicians to start treatment at an earlier stage.     

Serial cerebral computed tomography and magnetic resonance imaging in a case of hemolytic uremic syndrome with the complication of the central nervous system due to Escherichia coli O157:H7

We report serial cerebral computed tomography (CT) and magnetic resonance imaging (MRI) in a case of hemolytic uremic syndrome (HUS) with the complication of the central nervous system due to Escherichia coli O157:H7. Although initial brain CT was normal, follow-up CT and MRI revealed lesions in the white matter and bilateral basal ganglia, representing brain edema and infarcts, respectively. Especially, lesions in the bilateral basal ganglia were very unique. Serial CT and MRI findings are useful to understand the mechanism of the complications of the central nervous system associated with HUS.     

Management of cerebrospinal fluid fistulae: physiopathology, imaging and treatment

Cerebrospinal fluid (CSF) fistulae can produce leakage through a defect in the bony skull and meninges into the contiguous air-filled cavities at the base of the skull. The major risk is central nervous system infection. When abundant clear rhinorrhea or otorrhea is present, the diagnosis is obvious and imaging is used to localize the fistula. Computed tomography (CT) with millimetric slices and magnetic resonance imaging (MRI) are the most effective diagnostic tools. CT cisternography, an invasive procedure, should only be used when the diagnosis remains uncertain following CT scan and MRI. When CSF leakage is sparse or intermittent, the diagnosis can be made by measuring beta-2 transferrine in the escaping fluid. CT scan followed by MRI are also useful for making the diagnosis and locating the fistula when exterior leakage is absent. CT scan alone is effective for assessing isolated otorrhea. If the diagnosis remains uncertain after all these studies have been used, the patient should be closely followed clinically and isotopic study or surgery should be considered.     

First report of persistent dengue-1-associated autoimmune neurological disturbance: neuromyelitis optica spectrum disorder

Dengue virus (DENV) causes immune-mediated diseases. Neurological involvement represents a severe condition that is rarely observed in DENV-1 infection. Neuromyelitis optica (NMO)/NMO spectrum disorders (NMOSD) are idiopathic immune-mediated demyelinating syndromes of the central nervous system. We report a 17-year-old female with oligosymptomatic DENV-1 viremia, diagnosed as NMOSD. Magnetic resonance imaging showed spinal cord and brainstem lesions. Antibody for aquaporin 4 was negative. DENV-1 RNA infection was detected by serial RT-PCR and confirmed by phylogenetic analysis in serum. Although there are some reports of NMO post-dengue infection, there are not any published accounts of NMOSD with coexistent and persistent DENV-1 infection.     

Chlamydia pneumoniae infection associated with enhanced MRI spinal lesions in multiple sclerosis

Cerebrospinal fluid (CSF) from 66 patients with multiple sclerosis (MS) and 25 patients with other neurological diseases (OND) were examined for the infection of Chlamydia pneumoniae by culture, polymerase chain reaction (PCR) assay, and determination of antibodies to C. pneumoniae. PCR was positive not only in 9 of 28 (32%) patients with MS but also in 2 patents with inflammatory disorders in 15 (13%) OND controls (p = 0.18). Viable C. pneumoniae was isolated from one patient with MS and one with paraneoplastic encephalomyelitis. C. pneumoniae could be detected only in cell-containing CSF. In MS, enhanced spinal magnetic resonance imaging (MRI) lesions were detected in all of four PCR-positive patents but none of five PCR-negative patients, and the difference was significant (p = 0.0079). However, no correlation was found between enhanced brain MRI lesions and CSF C. pneumoniae DNA. Elevated titers of anti-C. pneumoniae IgG were detected in CSF in 13 of 66 (20%) patients with MS and 1 of 25 (4%) OND controls (p = 0.064). CNS C. pneumoniae infection is not uncommon in MS as well as in other inflammatory disorders of the nervous system. The association of active spinal lesions with Chlamydia in CSF collected by lumber puncture suggests the detection of a recent infection. On the other hand, the lack of association of active MS brain lesions with CSF Chlamydia and the presence of PCR-positive patents who are clinically stable and have no enhancing MRI lesions imply the existence of a chronic infectious process.     

MRI and proton MR spectroscopy in acute disseminated encephalomyelitis

Introduction Acute disseminated encephalomyelitis (ADEM) is one of a group of demyelinating disorders of the central nervous system (CNS). It is said to be attributed to an overshooting immunologic response following an infection or vaccination. The clinical course and type of manifestation is heterogeneous. The early application of corticosteroids has been shown to be beneficial to outcome; thus, an early diagnosis is highly desirable.Methods The potential diagnostic value of advanced MR techniques such as proton MR spectroscopy and diffusion-weighted imaging (DWI) was investigated in two paediatric patients with ADEM, one of whom had a remitting and relapsing clinical course and presented with additional cranial nerve involvement. Proton MR spectroscopy revealed typical signs of acute demyelination, such as increased macromolecules, not found in other forms of non-necrotising pathology.Conclusion The addition of proton MR spectroscopy and DWI adds to the diagnostic power of MRI in the setting of post-infectious demyelinating disorders of the CNS or ADEM and may obviate the need for biopsy.     

Non-MS autoimmune demyelination

Connective tissue diseases can be characterised by central nervous system (CNS) involvement, in some patients manifested by demyelination areas in the white matter of the brain and spinal cord, which are difficult to differentiate from multiple sclerosis (MS) and other demyelinating processes, such as transverse myelitis and optic neuritis. Demyelinating process may be the feature of nervous impairment in systemic lupus erythematosus, Behcet's disease (BD), Sjoegren's syndrome (SS), systemic sclerosis (SSc) or very rarely other systemic autoimmune diseases. An acute isolated neurological syndrome, as the most common symptom of MS can sometimes be the only feature or even first manifestation of nervous impairment in connective tissue disease, hence presenting the diagnostic problem. Although the white matter abnormalities seen by magnetic resonance imaging may be similar in non-MS autoimmune demyelination and MS, it is the most important diagnostic tool in the differential diagnosis of the mentioned conditions. Investigating the presence of various autoantibodies potentially involved in the pathogenesis of demyelinating lesions as well as cerebrospinal fluid (CSF) analysis can be helpful.     

儿童MOG抗体阳性的中枢神经系统脱髓鞘病变12例临床特点分析

目的探讨髓鞘少突胶质细胞糖蛋白(MOG)抗体阳性的儿童中枢神经系统脱髓鞘病变的临床特点。方法回顾性分析2016年1月至2018年12月广东三九脑科医院神经内科收治的12例儿童MOG抗体阳性的中枢神经系统脱髓鞘病患者的临床症状、影像学特点、实验室检查、预后及随诊情况。结果 12例患者中男4例,女8例,起病年龄5~10岁,平均(8.0±3.1)岁。首发症状以意识水平下降、癫痫大发作等急性播散性脑脊髓膜炎(ADEM)样症状最多见(8例,8/12),其次为视力下降(5例,5/12),其中1例以ADEM样症状和视力下降同时起病。另有3例以ADEM样症状首发,起病后1周左右出现视力下降。12例患者行头颅MRI检查,11例(11/12)可见颅内异常病灶,以皮层下白质(10例,10/11)、脑干(7例,7/11)、丘脑(6例,6/11)、视神经(5例,5/11)受累为主,小脑(4例,4/11)、胼胝体(1例,1/11)亦可受累。9例患者行全脊髓MRI检查,5例(5/9)有异常病灶,均累及颈髓(5例,5/5),3例(3/5)累及胸髓,累及胸髓的病灶均为>3个椎体节段的长节段脊髓受累。12例患者行血清MOG抗体检测,11例(11/12)阳性,另1例(1/12)血清抗体阴性而脑脊液抗体阳性;8例患者行脑脊液MOG抗体检测,3例(3/8)阳性。所有患者经糖皮质激素及免疫球蛋白治疗,预后均良好,3例患者出现复发。结论MOG抗体相关的儿童中枢神经系统脱髓鞘病变以ADEM、视神经脊髓炎谱系疾病(NMOSD)最常见,往往以意识水平下降、癫痫大发作或视力下降起病,其预后相对较好,糖皮质激素治疗对缓解临床症状及预防复发有重要作用。     

Update on neuroimaging in infectious central nervous system disease

PURPOSE OF REVIEW: Neuroimaging constitutes an important component in the diagnosis of the underlying infectious agents in central nervous system infection. This review summarizes progress in the neuroimaging of infectious central nervous system disease since January 2003. It focuses on imaging of viral encephalitis, including that caused by exotic and emerging viruses, and on imaging in immunodeficient patients. RECENT FINDINGS: Diffusion-weighted imaging has been shown to be superior to conventional magnetic resonance imaging for the detection of early signal abnormalities in herpes simplex virus encephalitis but also in enterovirus 71 encephalitis and in West Nile encephalitis. Several studies defined the pattern of magnetic resonance imaging signal changes in endemic diseases such as West Nile encephalitis, Murray Valley encephalitis, enterovirus 71 encephalitis and Japanese encephalitis, but also in encephalitides due to ubiquitous viruses such as measles virus and Lyssavirus (rabies). In patients with HIV infection, apparent diffusion coefficient ratios obtained by diffusion-weighted imaging were significantly greater in lesions due to Toxoplasma encephalitis than in primary central nervous system lymphomas. SUMMARY: The diagnosis of unclear infectious central nervous system diseases remains a challenge. More recent magnetic resonance imaging techniques, such as diffusion-weighted imaging and magnetic resonance spectroscopy, provide additional helpful information. However, the mainstay of diagnosis remains the detection of viral DNA or serological markers of specific infectious agents within the cerebrospinal fluid.     

The usefulness of MRI of the central nervous system in certain diseases of blood and hemopoietic system with neurological symptoms

The results are presented of MRI studies of the brain and spinal cord in patients with neurological symptoms in the course of certain diseases of the haemopoietic system (leukaemias, lymphomas). The analysis showed that MR images, although not specific, can be very useful for the evaluation of the intensity and topography of haematological lesions in the central nervous system. However, the diagnosis of these processes is not easy. In the differential diagnosis focal lesions of vasogenic origin, infections and radiation-induced lesions should be considered, and in cases of lymphoma--metastases are a possibility.     

Magnetic resonance imaging in pediatric neurologic disorders

We present our initial experience with magnetic resonance imaging (MRI) in 301 pediatric patients with a variety of neurologic disorders. MRI does not require ionizing radiation and can be done easily and safely in children. It is equal or superior to computed cranial tomographic (CT) scans in demonstrating most types of pediatric neurologic disorders. MRI is often superior to CT scans in demonstrating intracranial tumors, although both studies are usually abnormal in highly malignant tumors. No clear advantage was shown with either MRI or CT scans for fluid-filled intracranial lesions. Lesions of the brain stem and upper cervical region, such as Chiari malformation, are well delineated by MRI. Increased signal from the paranasal sinuses was frequently evident by MRI, but, in most instances, there was no clinical indication of sinus disease. Large arteries can be visualized as an area of diminished signal, and intracranial hemorrhage, dural sinus thrombosis, and cerebral infarction were demonstrated. The increased anatomic detail pictured by MRI allows the diagnosis of congenital defects, such as agenesis of the corpus callosum or septum pellucidum, that are not always apparent with CT scans. Although our experience with spinal cord lesions was not extensive, fluid-filled lesions within the cord can be reliably demonstrated.     

瘤样炎性脱髓鞘病的影像学特点观察

目的分析瘤样炎性脱髓鞘病(TIDD)影像特点,探讨磁共振(MRI)特别是强化和弥散加权成像(DWI)检查技术对于TIDD的诊断价值。方法对16例TIDD患者行头颅CT和MRI扫描。结果病灶在头颅CT均为低信号,在MRI平扫上呈T1WI低、T2WI高信号,强化像上可见强化,57%可见开环征,发病早期DWI可见高信号,FLAIR较T1WI及T2WI能显示更清晰的病灶及范围。结论使用多种影像技术可以辅助诊断TIDD,并与脑缺血或肿瘤相鉴别,能区分病灶所处时期,因此,影像检查是诊断TIDD的有效辅诊方法之一。     

Peripheral neurofibromatosis and involvement of lumbosacral nerves. Value of imaging

We report a case of giant plexiform neurofibromatosis revealed by a sensori-motor, axo-myelinic polyneuropathy. Only the lumbar and sacral spinal nerves were involved in this peripheral form of Von Recklinghausen's disease. The polyneuropathy was due to compression of the nervous fibers by the neurofibromatous tumors. Ultrasonography DTPA 99 m Technetium scintigraphy, CT and MRI were the diagnostic procedures. MRI proved superior to CT in demonstrating the extent of the lesions. Biopsy confirmed the diagnosis. This form of neurofibromatosis did not involve the central nervous system, cranial nerves of cervicothoracic spinal nerves and roots; nor was there any visceral involvement, particularly endocrine neoplasia.     

Pathology of tropical diseases

Tropical diseases affecting the central nervous system include infections, infestations, and nutritional deficiency disorders. This article discusses the commonly encountered diseases. The infections include bacterial, mycobacterial, fungal, parasitic, and viral infections with varied clinical manifestations. Imaging sensitivity and specificity for the prediction of the cause of infections has improved with application of advanced techniques. Microbial demonstration and histology remain the gold standard for diagnosis. Understanding the basis of imaging changes is mandatory for better evaluation of images. Nutritional disorders present with generalized and nonspecific imaging manifestations. The pathology of commonly encountered vitamin deficiencies is also discussed.     

儿童抗MOG抗体及抗NMDAR抗体双阳性中枢神经系统脱髓鞘1例报道并文献复习

目的 探讨缺血性脑卒中(Cerebral ischemic stroke,CIS)患者发生睡眠呼吸紊乱(Sleep-disordered breathing,SDB)的影响因素。方法 纳入2018年2月-2019年4月本院神经内科收治的288例首次发病的CIS患者,于发病后的第7 d左右采用Apnea Link^TM睡眠测试装置整夜连续进行呼吸睡眠检测,发生SDB的患者[呼吸暂停-低通气指数(Apnoea-hypopnoea index,AHI)≥10]纳入研究组,未发生SDB的患者纳入对照组,考察CIS患者中SDB的发生率,采用单因素分析的方法比较发生SDB的可疑危险因素,对于单因素分析有意义的自变量,采用Logistic回归逐步向前法进一步识别SDB的独立影响因素。结果 CIS患者中SDB的发病率为63.1%。多因素Logistic回归分析显示,年龄≥65岁[OR(95%CI)=2.078(1.317～3.28),P=0.002]、脑干病变[OR(95%CI)=2.306(1.418～3.75),P=0.001]、NIHSS得分[OR(95%CI)=2.368(1.34～4.185),P=0.003]、mRS得分[OR(95%CI)=2.033(1.146～3.606),P=0.015]和发生吞咽困难[OR(95%CI)=2.392(1.031～5.545),P=0.042]是脑卒中患者发生SDB的独立危险因素。结论 脑干损伤是脑卒中患者发生SDB的主要危险因素,而SDB加重了急性期缺血性脑卒中患者的神经系统症状,老年缺血性脑卒中患者是SDB的易感人群。对脑干损伤的老年患者,要重视早期监测呼吸睡眠功能,发生SDB迹象时要及时采取干预措施。