Diffusion weighted magnetic resonance imaging in Neuro-Behçet's disease

Unique presentation of acute neuro-Behçet's disease involving a cytotoxic oedema core surrounded by vasogenic oedema

A 53-year-old woman with recurrent stomatitis, genital ulcers, and folliculitis was admitted to Tokyo Medical University Hospital after experiencing visual disturbances for the past 2 weeks and a nonthrobbing headache for the past 3 days. She had also developed numbness in her left extremities. An ophthalmological examination revealed inflammatory changes in the eye. Cerebrospinal fluid analysis showed increased cell counts, protein, and interleukin-6 levels. Brain magnetic resonance imaging revealed multiple high signal intensities on T2-weighted/fluid-attenuated inversion recovery images of the pons and occipital and parietal lobes. The T2-weighted/fluid-attenuated inversion recovery high-signal-intensity lesion in the pons was hyperintense on diffusion-weighted imaging and hypointense on apparent diffusion coefficient mapping, suggesting cytotoxic oedema. Another high-signal-intensity lesion on T2-weighted/fluid-attenuated inversion recovery was isointense to hyperintense on diffusion-weighted imaging and hyperintense on apparent diffusion coefficient, indicating vasogenic oedema. The vasogenic oedema in the left occipital lobe contained a small core that was hyperintense on diffusion-weighted imaging and hypointense on apparent diffusion coefficient, suggesting cytotoxic oedema. The patient was diagnosed with acute neuro-Behçet's disease and responded well to high-dose glucocorticoid and colchicine treatment. The present report emphasises that patients with acute neuro-Behçet's disease may present with cytotoxic oedema in the pons and cerebral spheres. Further reports of similar cases would contribute to a better understanding of the role of cytotoxic oedema in the pathophysiology of neuro-Behçet's disease and help elucidate the mechanisms underlying a unique presentation characterised by a central cytotoxic oedema core within vasogenic oedema.

Uncommon and Miscellaneous Inflammatory Disorders of the Brain and Spine

Inflammatory disorders of the brain and spine have a highly variable MRI appearance, often demonstrating significant overlap in imaging features. The resulting diagnostic dilemma is particularly challenging when considering the more uncommon neuroinflammatory entities. Diligent examination of the salient clinical presentation and signal alteration on imaging examination is necessary when considering neuroinflammation as a diagnostic possibility and may aid in raising suspicion for a particular neuroinflammatory entity. This article reviews a selection of uncommon and miscellaneous inflammatory disorders of the brain and spine to raise awareness of the clinical and imaging features that may assist in this challenging diagnostic task.

Neurological involvement by Behçet's syndrome: clinical features, diagnosis, treatment and outcome

Neurological involvement in Behçet's syndrome arises predominately through an inflammatory meningoencephalitis characterised by perivenular inflammation due to activation of Th-17 immunological pathways. The brainstem is involved in 50% of cases, the diencephalon and other areas of the brain in 30%, and the spinal cord in 10%. Movement disorders and epilepsy may occur. Psychiatric syndromes may arise with brain and brainstem involvement, and cognitive disorders relate to the brain disease, to circulating inflammatory factors, and to fatigue and despondency. Eighty per cent of cases begin with a relapsing disease course, of whom 70% have only one attack, and 30% have a progressive disease course either from onset or following an initially relapsing course. Venous thrombosis leading to intracranial hypertension and cerebral venous infarction is less common and caused by inflammation in affected veins and a circulating prothrombotic state. Arterial involvement is rare and relates to an arteritis affecting large-sized and medium-sized vessels within the brain leading to infarction, subarachnoid and parenchymal haemorrhage, aneurysm formation and arterial dissection. There is a newly recognised disorder of cerebral cortical hypoperfusion. Cranial neuropathy, peripheral neuropathy and myositis are rare. There has been significant progress in understanding the pathophysiology and treatment of the systemic disease, leading to improved outcomes, but there has been no randomised trial of treatment in the neurological disorder.

Neuro-Behcet's disease: An update on diagnosis, differential diagnoses, and treatment

Neuro-Behcet's disease (NBD) is defined as a combination of neurologic symptoms and/or signs in a patient with Behcet's disease (BD). Relevant syndromes include brainstem syndrome, multiple-sclerosis like presentations, movement disorders, meningoencephalitic syndrome, myelopathic syndrome, cerebral venous sinus thrombosis (CVST), and intracranial hypertension. Central nervous involvement falls into parenchymal and non-parenchymal subtypes. The parenchymal type is more prevalent and presents as brainstem, hemispheric, spinal, and meningoencephalitic manifestations. Non-parenchymal type includes CVST and arterial involvement. Perivascular infiltration of polymorphonuclear and mononuclear cells is seen in most histo-pathologic reports. In parenchymal NBD, cerebrospinal fluid (CSF) generally exhibits pleocytosis, increased protein and normal glucose. In NBD and CVST, CSF pressure is increased but content is usually normal. The typical acute NBD lesions in brain magnetic resonance imaging (MRI) are mesodiencephalic lesions. The pattern of extension from thalamus to midbrain provides a cascade sign. Brain MRI in chronic NBD usually shows brain or brainstem atrophy and/or black holes. The spinal MRI in the acute or subacute myelopathies reveals noncontiguous multifocal lesions mostly in cervical and thoracic lesions. In chronic patients, cord atrophy can also be seen. Brain MRI (particularly susceptibility-weighted images), MR venography (MRV) and computerized tomographic venography (CTV) can be used to diagnose CVST. Parenchymal NBD attacks can be treated with glucocorticoids alone or in combination with azathioprine. For patients with relapsing-remitting or progressive courses, shifting to more potent immunosuppressive drugs such as mycophenolate, methotrexate, cyclophosphamide, or targeted therapy is warranted. For NBD and CVST, immunosuppressive drugs with or without anticoagulation are suggested.

Apparent diffusion coefficient characteristics of parenchymal neuro-Behçet's disease

AIM

To evaluate apparent diffusion coefficient (ADC) characteristic of parenchymal neuro-Behçet's disease (NBD).

METHODS

We retrospectively reviewed cranial magnetic resonance imaging (MRI) examinations of NBD patients with acute or chronic parenchymal lesions. ADC measurements of the lesions and contralateral normal brain parenchyma were performed by a consensus of two radiologists. To compare the ADC value of the chronic and acute lesions, relative ADC values (rADC) were calculated. The ratio of the lesions' ADC to contralateral normal brain parenchyma ADC yielded a rADC value of the lesions. Contrast enhancement patterns and the locations of the lesions were also noted.

RESULTS

A total of 24 NBD patients with 45 parenchymal lesions, 25 acute, and 20 chronic, were enrolled in the study. A significant difference was observed between the mean ADC value of the acute lesions (1074.48 ± 138.31 m/s) and the mean ADC value of the contralateral normal brain parenchyma (841.20 ± 142.96 m/s; P < 0.0001). A significant difference was observed between the mean ADC value of the chronic lesions (1069.95 ± 143.95 m/s) and the mean ADC value of the contralateral normal brain parenchyma (793.90 ± 96.71 m/s; P < 0.0001). No significant difference was observed between the mean rADC (1.35 ± 0.20) and the mean rADC value of the chronic lesions (1.29 ± 0.15; P = 0.22).

CONCLUSIONS

ADC measurements might provide substantial information about the histopathological aspect of parenchymal NBD lesions.

Neuro-Behçet syndrome

Behçet syndrome (BS) is an idiopathic chronic relapsing multisystem vascular-inflammatory disease of unknown origin. As the disease affects many organs and systems and shows a wide range of clinical manifestations and presentations, it is prefereable to call Behçet's a syndrome (BS) rather than a disease. Nervous system involvement, known as "neuro-BS" (NBS), is seen in about 5-10% of all cases. Clinical and imaging evidence suggests that primary neurologic involvement in BS may be subclassified into two major forms: the first, which is seen in the majority of patients, may be characterized as a vascular-inflammatory central nervous system disease with focal or multifocal parenchymal involvement, mostly presenting with a subacute brainstem syndrome and hemiparesis (intra-axial NBS); the other, which has few symptoms and a better neurologic prognosis, may be caused by isolated cerebral venous sinus thrombosis and intracranial hypertension (extra-axial NBS), occurring in 10-20% of the cases. These two types are rarely seen in the same individual, and their pathogenesis is likely to be different. Isolated behavioral syndromes and peripheral nervous system involvement are rare, whereas a vascular type headache is relatively common and independent from neurologic involvement. Neurologic complications secondary to systemic involvement of BS, as well as neurologic complications related to BS treatments are considered as secondary neurologic involvement of the syndrome. The core histopathologic phenomenon seems to be a vasculitic involvement in some cases, and low-grade chronic nonspecific inflammation in others. As the neurologic involvement in this syndrome is so heterogeneous, it is difficult to predict its course and prognosis, and its response to treatment. Currently, treatment options for NBS are limited to attack therapies with high-dose intravenous methylprednisolone followed by a prolonged oral taper, symptomatic management, and generally the use of azathioprine, cyclophosphamide, interferon-α and anti-TNF agents for long-term preventive treatment, although there no evidence for their efficacy.

Transient Brain Lesions in Neuro-Behçet's Disease without Systemic Involvement

In neuro-Behçet's disease nervous involvement may occasionally precede somatic manifestations, making the diagnosis challenging. The reported case showed only a neurologic onset with relapsing-remitting form, transient brain MRI abnormalities and late appearance of typical muco-cutaneous lesions, thereby delaying the correct diagnosis and appropriate treatment. MRI revealed cerebral alterations mimicking demyelinating disease, but lesions rapidly disappeared on close follow-up scans indicating vasogenic edema. Being aware of this atypical presentation and recognizing these transient abnormalities may be useful for a prompt diagnosis.

Brain perfusion MRI findings in patients with Behcet's disease

Objective. To search brain perfusion MRI (pMRI) changes in Behcet's disease (BD) with or without neurological involvement. Materials and Method. The pMRI were performed in 34 patients with BD and 16 healthy controls. Based on neurologic examination and post-contrast MRI, 12 patients were classified as Neuro-Behcet (group 1, NBD) and 22 patients as BD without neurological involvement (group 2). Mean transit time (MTT), time to peak (TTP), relative cerebral blood volume (rCBV), and relative cerebral blood flow (rCBF) were obtained and compared to those of healthy control group (group 3). Results. There was a significant difference in the MTT and rCBF within the pons and parietal cortex in groups 1 and 2. rCBV increased in cerebral pedicle in group 1 compared with groups 2 and 3. In the temporal lobe white matter, prolonged MTT and decreased rCBF were found in groups 1 and 2. In the corpus striatum, internal capsule, and periventricular white matter, rCBF increased in group 1 compared with group 3 and decreased in groups 1 and 2. Conclusion. Brain pMRI is a very sensitive method to detect brain involvement in patients with BD and aids the clinical diagnosis of NBD, especially in patients with negative MRI findings.

Intra-axial pseudotumors in the central nervous system: clinicopathological analysis

Intra-axial pseudotumors in the central nervous system often mimic malignant brain tumors and cause difficulty in diagnosis and treatment. The present study investigates their radiologic and histological features to elucidate diagnostic clues. Six cases were included in the study, one man and five women, ranging in age from 44 to 87 years (mean age, 61 years). Histologically, three cases had demyelination, and one case each had abscess, angiitis, and non-Langerhans cell histiocytosis. All cases were evaluated radiologically on MRI, most of them by thallim-201 single photon emission tomography ((201)Tl-SPECT). These cases were examined using H&E, special stains, and immunohistochemical studies with a variety of antibodies. MRI demonstrated perifocal edema and ring-like or solid enhancement, mimicking the malignant tumors. Diffusion-weighted MRI showed a hypo-iso-intensity with a hyperintensity on the apparent diffusion coefficient. A (201)Tl-SPECT study revealed no uptake. Although there were various kinds of pathology, inflammatory cells were observed, associated with vascular proliferation and reactive astrocytosis. In addition, some cases showed demyelinating or destructive changes. These results suggested that intra-axial pseudotumors in the central nervous system contain various kinds of pathology, and detailed clinicopathological analysis is important from the point of view of differential diagnosis.

Treatment of neuro-Behçet's disease: an update

Neurological manifestations of Behçet's disease (neuro-Behçet's disease) present in 5-30% of cases. They are classified into parenchymal and nonparenchymal categories. Poor prognostic factors include multifocal involvement, spinal presentations, more than two attacks per year, progressive course and increased cerebrospinal fluid cell count and protein content at the time of neurologic manifestations. For patients with parenchymal neuro-Behçet's disease without any poor prognostic factor, azathioprine or methotrexate and corticosteroids are recommended as the first-line treatment. For high-risk patients, intravenous cyclophosphamide and corticosteroids are recommended. If these regimens failed, TNF-alpha-blocking drugs, such as infliximab or etanercept, should be added. Alternating IFN-alpha and then chlorambucil or experimental treatments are the last resorts for most refractory patients. Treatment of venous sinus thrombosis is achieved by using anticoagulation and short-term corticosteroids with or without immunosuppressants.

The spectrum of nervous system involvement in Behçet's syndrome and its differential diagnosis

Behçet's Syndrome (BS) is a multi-system, vascular-inflammatory disease of unknown origin, involving the nervous system in a subgroup of patients. The growing clinical and imaging evidence suggests that primary neurological involvement in BS may be subclassified into two major forms: the first one, which is seen in the majority of patients, may be characterized as a vascular-inflammatory central nervous system (CNS) disease, with focal or multifocal parenchymal involvement mostly presenting with a subacute brainstem syndrome and hemiparesis; the other, which has few symptoms and a better neurological prognosis, may be caused by isolated cerebral venous sinus thrombosis and intracranial hypertension. These two types rarely occur in the same individual, and their pathogenesis is likely to be different. Isolated behavioral syndromes and peripheral nervous system involvement are rare, whereas a nonstructural vascular type headache is relatively common and independent from neurological involvement. Neurologic complications secondary to systemic involvement of BS such as cerebral emboli from cardiac complications of BS and increased intracranial pressure due to superior vena cava syndrome, as well as neurologic complications related to BS treatments such as CNS neurotoxicity with cyclosporine and peripheral neuropathy with the use of thalidomide or colchisin are considered as secondary neurological complications of this syndrome. As the neurological involvement in this syndrome is so heterogeneous, it is difficult to predict its course and prognosis, and response to treatment. Currently, treatment options are limited to attack and symptomatic therapies with no evidence for the efficacy of any long term preventive treatment.

Cytotoxic edema in neuro-Behcet's disease ?

We report a case of a 52-year-old woman with Behcet's disease who presented with dysarthria and right-sided hemiparesis. T2-weighted and diffusion-weighted images (DWI) showed a hyperintense lesion in the left pons with a relatively decreased apparent diffusion coefficient (ADC). Imaging showed almost complete resolution of the lesion after treatment with prednisolone. The atypical DWI and ADC findings in this case may reflect cytotoxic edema due to excitotoxic brain injury. This case thus illustrates the radiological diversity of neuro-Behcet's lesions.

Diffusion-weighted imaging in chronic Behçet patients with and without neurological findings

Our aim was to investigate whether neurological impairment in chronic Behçet's disease (BD) patients with normal appearing brain can be assessed by means of diffusion-weighted imaging (DWI). The averaged apparent diffusion coefficient (ADC) values were calculated in 22 different radiologically normal appearing brain regions in 32 patients with and without neurological findings and 20 control subjects. The ADC values in bilateral frontal, temporal and occipital normal appearing white matter were significantly higher in the patient groups compared with the control subjects (p < 0.05). In these brain regions, DWI revealed differences in the ADC values between patients with neurological findings (including symptomatic and neuro-Behçet patients) and the asymptomatic patient group. The similarity of the ADC values of patients without symptoms to those of the control group allowed clear discrimination between patients with and without neurological findings. DWI may serve to assess subclinical neurological involvement in BD, even when structural changes are absent.

Neuro-Behçet Disease

BACKGROUND

Behçet disease is a vasculitis with mucocutaneous, ocular, arthritic, vascular, and other manifestations. Its neurologic manifestations (neuro-Behçet disease) are relatively rare, but they must be thoroughly investigated due to their grave prognosis.

REVIEW SUMMARY

The frequency of neurologic manifestations, more common in male Behçet patients, is between 5% and 30%. Both the central and peripheral nervous systems can be involved. Central nervous system manifestations can be divided into 2 main groups: (1) parenchymal involvement, which includes brainstem involvement, hemispheric manifestations, spinal cord lesions, and meningoencephalitic presentations; (2) nonparenchymal involvement, including dural sinus thrombosis, arterial occlusion, and/or aneurysms. Peripheral neuropathy and myopathy are relatively rare. Cerebrospinal fluid analysis reveals pleocytosis and elevated protein levels. Magnetic resonance imaging is the investigation of choice which often reveals iso-/hypointense lesions in T1-weighted images and hyperintense lesions in T2-weighted images, mostly in the mesodiencephalic junction, cerebellar peduncles, and other parts of the brainstem. Corticosteroids and adjuvant immunosuppressive therapy are used for parenchymal manifestations, and corticosteroids and anticoagulants are used for treatment of dural sinus thrombosis.

CONCLUSION

Neuro-Behçet disease must be considered in the differential diagnosis of stroke in young adults, multiple sclerosis, movement disorders, intracranial hypertension, intracranial sinovenous occlusive diseases, and other neurologic syndromes.

Magnetization transfer ratio in neuro-Beh�et disease

The aim of this study was to determine the contribution of magnetization transfer ratios (MTRs) in detecting disease in normal-appearing brain regions of patients with neuro-Behçet (NB) disease. Thirty-two patients with NB disease were assessed. Fifteen healthy volunteers were examined as the control group. Magnetic resonance (MR) imaging of the head was performed without and with magnetization transfer (MT) contrast. Signal intensity measurements were obtained from ten anatomical regions (centrum semiovale, corona radiata, internal capsule, forceps major, forceps minor, thalamus, substantia nigra pars compacta, substantia nigra pars grisea, inferior pons and middle cerebellar peduncle) in both groups. Also measured in the NB group were parenchymal lesions in the brain stem, basal ganglia and cerebral deep white matter. MTR was calculated for each measurement. Statistical analysis was performed with Mann-Whitney U and independent t-tests with computer-based SPSS 11.0 for Windows software. A P value below 0.05 was considered statistically significant. The mean MTR of the parenchymal lesions in the NB group was lower than the mean MTR of the normal-appearing parenchyma in both the NB patients and the normal group. For the normal-appearing parenchyma the mean MTR in the NB group was higher than that for the controls for all regions except the corona radiata; however, the difference was statistically significant only for the thalamus. The MRI-visible parenchymal involvement of Behçet's disease causes a decrease in MTR. For the normal-appearing brain, although lacking statistical significance for the most regions studied, the tendency for higher MTR in NB patients compared with controls may offer an insight into the pathophysiology of Behçet's disease.

CNS vasculitis and vasculopathy: efficacy and usefulness of diffusion-weighted echoplanar MR imaging

This pictorial essay illustrates the usefulness of diffusion-weighted imaging (DWI) on various vasculitis or vasculopathies, including systemic lupus erythematosus (SLE), Behçet's disease, Churg-Strauss disease, primary angitis of the central nervous system (PACNS), giant cell arteritis, infectious vasculitis, sickle cell disease, drug-induced vasculopathy and hypertensive vasculopathy. DWI proves to detect small and active ischemic changes not visible on conventional MRI, and it clearly discriminates cytotoxic from vasogenic edema in patients with cerebral vasculitis or vasculopathy. DWI seems useful in assessing the treatment and patient outcome.

Beh??et??s syndrome and the nervous system

PURPOSE OF REVIEW

Behçet's syndrome (BS) is a multi-system, vascular-inflammatory disease of unknown origin, involving the nervous system in a subgroup of patients. The syndrome is rare, but as patients with BS are young and frequently present with an acute or subacute brainstem syndrome or hemiparesis, as well as with other various neurological manifestations, the syndrome is often included in the differential diagnosis of multiple sclerosis, stroke of the young adult, and another wide range of neurological disorders. The present review summarizes the neurological involvement in BS, and emphasizes recent clinical concepts and ethiopathogenetic findings.

RECENT FINDINGS

Over the last years the growing clinical and imaging evidence had suggested that neurological involvement in BS may be subclassified into two major forms: one, which is seen in the majority of patients, may be characterized as a vascular-inflammatory CNS disease, with focal or multifocal parenchymal involvement; the other, which has few symptoms and a better neurological prognosis, may be caused by isolated cerebral venous sinus thrombosis and intracranial hypertension. These two types rarely occur in the same individual, and their pathogenesis is likely to be different. A nonstructural vascular type headache is relatively common, whereas isolated behavioral syndromes and peripheral nervous system involvement are rare.

SUMMARY

The involvement of the nervous system in BS is heterogeneous as clinical and imaging data reveal. Currently it is unknown which factors determine or have a role in the development of neurological involvement, but some progress has been achieved in understanding the neurological spectrum of the syndrome, which may lead to a better management of these patients.

Diffusion-weighted MR findings in isolated angiitis of the central nervous system (IACNS)

OBJECTIVES

To describe the diffusion-weighted MR (DWI) findings of isolated angiitis of the central nervous system (IACNS) and narrow the differential diagnosis.

METHODS

The DWI findings of two IACNS patients. Apparent diffusion coefficient (ADC) values were measured in the abnormal lesions, and DWI and T2-weighted MR images were visually inspected.

RESULTS

IACNS was diagnosed based on clinical history, MR findings and cerebral angiographic findings. DWI showed hyperintense lesions with heterogeneous ADC values (287-1359 x 10(-6) mm2/s), which indicate the coexistence of cytotoxic and vasogenic oedema.

CONCLUSIONS

The findings suggest that the various stages of inflammatory process with ischaemia might exist in IACNS and allow a differentiation from the usual arterial ischaemic infarction. DWI with ADC map can be a useful non-invasive diagnostic test increasing specificity in the diagnosis of IACNS, combined with conventional MRI and cerebral angiography.

Neuro-Behcet's disease: diffusion MR imaging and proton MR spectroscopy

We herein report the case of a 53-year-old woman with Behcet's disease and an acute T2-hyperintense lesion in left side of the pons. Echo-planar "trace" diffusion MR imaging revealed high signal intensity changes at the lesion site on b = 1000 s/mm(2) images, initially suggesting restricted diffusion. On corresponding apparent diffusion coefficient maps, however, the lesion had high signal intensity and high apparent diffusion coefficient values (1.22 x 10(-3) mm(2)/s), compared with the contralateral normal side of the pons (0.86 x 10(-3) mm(2)/s) and compared with the normal temporal white matter (0.80 x 10(-3) mm(2)/s). This was consistent with the presence of increased diffusion, hence vasogenic edema. Proton MR spectroscopy excluded acute infarction. This particular pattern (high signal intensity on b = 1000 s/mm(2) images in association with high apparent diffusion coefficient values) likely represented the acute inflammatory process associated with disrupted brain-blood barrier in the fulminant form of neuro-Behcet's disease. Follow-up examinations </=2 years later revealed a remaining gliotic lesion.

Neuro-Behçet's disease: analysis of apparent diffusion coefficients

Little is known about the diffusion properties of brain lesions in neuro-Behçet's disease (NBD). We looked at 19 NBD lesions (13 active, six chronic) in six patients, using diffusion-weighted MRI (DWI). We calculated the apparent diffusion coefficients (ADC) of the lesions and compared them with normal contralateral brain, expressing this ratio as relative ADC (rADC). The rADC was 1.29+/-0.33 in active and 1.44+/-0.47 in chronic lesions, i.e., significantly higher than in the control regions. Increased diffusivity in both active and chronic phases in NBD is different from the pattern in ischaemic infarcts, so that ADC analysis might be helpful for differentiating between these conditions.

Diffusion-weighted MR imaging of neuro-Behçet's disease: a case report

We present a serial study of diffusion-weighted imaging (DWI) in a patient with neuro-Behçet's disease. Initial T2-weighted magnetic resonance images showed a hyperintense lesion in the brain stem. The lesion was slightly hyperintense on DWI and the apparent diffusion coefficient (ADC) was slightly increased. Ten months later, DWI showed an improvement in the abnormal signal intensity and the region of increased ADC had increased in size, especially on the left side. DWI is useful for differentiating an acute exacerbation of neuro-Behçet's disease from acute infarction.