Detection of cerebral involvement in patients with active neuropsychiatric systemic lupus erythematosus by the use of volumetric magnetization transfer imaging

The conundrum of neuropsychiatric systemic lupus erythematosus: Current and novel approaches to diagnosis

Recognising neuropsychiatric involvement by systemic lupus erythematosus (SLE) is of growing importance, however many barriers to this exist at multiple levels of our currently available diagnostic algorithms that may ultimately delay its diagnosis and subsequent treatment. The heterogeneous and non-specific clinical syndromes, serological and cerebrospinal fluid (CSF) markers and neuroimaging findings that often do not mirror disease activity, highlight important research gaps in the diagnosis of neuropsychiatric SLE (NPSLE). Formal neuropsychological assessments or the more accessible screening metrics may also help improve objective recognition of cognitive or mood disorders. Novel serum and CSF markers, including autoantibodies, cytokines and chemokines have also shown increasing utility as part of diagnosis and monitoring, as well as in distinguishing NPSLE from SLE patients without SLE-related neuropsychiatric manifestations. Novel neuroimaging studies also expand upon our existing strategy by quantifying parameters that indicate microarchitectural integrity or provide an assessment of neuronal function. Some of these novel markers have shown associations with specific neuropsychiatric syndromes, suggesting that future research move away from considering NPSLE as a single entity but rather into its individually recognized neuropsychiatric manifestations. Nevertheless, it is likely that a composite panel of these investigations will be needed to better address the gaps impeding recognition of neuropsychiatric involvement by SLE.

Multi-lesion radiomics model for discrimination of relapsing-remitting multiple sclerosis and neuropsychiatric systemic lupus erythematosus

OBJECTIVES

To develop an MRI-based multi-lesion radiomics model for discrimination of relapsing-remitting multiple sclerosis (RRMS) and its mimicker neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

A total of 112 patients with RRMS (n = 63) or NPSLE (n = 49) were assigned to training and test sets with a ratio of 3:1. All lesions across the whole brain were manually segmented on T2-weighted fluid-attenuated inversion recovery images. For each single lesion, 371 radiomics features were extracted and trained using machine learning algorithms, producing Radiomics Index for Lesion (RIL) for each lesion and a single-lesion radiomics model. Then, for each subject, single lesions were assigned to one of two disease courts based on their distance to decision threshold, and a Radiomics Index for Subject (RIS) was calculated as the mean RIL value of lesions on the higher-weighted court. Accordingly, a subject-level discrimination model was constructed and compared with performances of two radiologists.

RESULTS

The subject-based discrimination model satisfactorily differentiated RRMS and NPSLE in both training (AUC = 0.967, accuracy = 0.892, sensitivity = 0.917, and specificity = 0.872) and test sets (AUC = 0.962, accuracy = 0.931, sensitivity = 1.000, and specificity = 0.875), significantly better than the single-lesion radiomics method (training: p < 0.001; test: p = 0.001) Besides, the discrimination model significantly outperformed the senior radiologist in the training set (training: p = 0.018; test: p = 0.077) and the junior radiologist in both the training and test sets (training: p = 0.008; test: p = 0.023).

CONCLUSIONS

The multi-lesion radiomics model could effectively discriminate between RRMS and NPSLE, providing a supplementary tool for accurate differential diagnosis of the two diseases.

KEY POINTS

• Radiomic features of brain lesions in RRMS and NPSLE were different. • The multi-lesion radiomics model constructed using a merging strategy was comprehensively superior to the single-lesion-based model for discrimination of RRMS and NPSLE. • The RRMS-NPSLE discrimination model showed a significantly better performance or a trend toward significance than the radiologists.

Altered Temporal Dynamics of Brain Activity in Multiple-Frequency Bands in Non-Neuropsychiatric Systemic Lupus Erythematosus Patients with Inactive Disease

PURPOSE

In this study, we seek to investigate dynamic changes of brain activity in non-neuropsychiatric systemic lupus erythematosus (non-NPSLE) patients with inactive disease.

PATIENTS AND METHODS

Thirty-one non-NPSLE patients with inactive disease and 20 matched healthy controls underwent the blood oxygenation level-dependent fMRI examination. Dynamic regional homogeneity (ReHo) and fractional amplitude of low-frequency fluctuations (fALFF) were used to analyze the brain activity in typical band (0.01-0.08 Hz), slow-4 (0.027-0.073 Hz) and slow-5 (0.01-0.027 Hz). Pearson's correlation analysis was performed to correlate dynamic regional homogeneity (dReHo) and dynamic fractional amplitude of low-frequency fluctuations (dfALFF) values for clusters of voxels where significant group differences were found with clinical variables in non-NPSLE patients with inactive disease.

RESULTS

In typical band, non-NPSLE patients showed increased dReHo in left middle occipital gyrus (MOG) compared to healthy controls. Meanwhile, patients showed decreased dfALFF in right superior frontal gyrus (SFG) and bilateral middle frontal gyrus (MFG) in typical band. In slow-4, increased dReHo in left MOG was found in non-NPSLE patients. In slow-5, non-NPSLE patients showed increased dReHo in left MOG, left calcarine fissure and surrounding cortex, right precentral gyrus (PreCG) and left postcentral gyrus (PoCG). Meanwhile, non-NPSLE patients showed decreased dfALFF in left SFG, right MFG, and right PreCG in slow-5. Moreover, the glucocorticoid dose showed significantly negative correlations with dReHo values in right PreCG in slow-5, left PoCG in slow-5, and left MOG in typical band.

CONCLUSION

dReHo and dfALFF abnormalities in different frequency bands may be the key characteristics in the pathogenesis mechanism of non-NPSLE.

Combined Brain/Heart Magnetic Resonance Imaging in Systemic Lupus Erythematosus

Cardiovascular Disease (CVD) in Systemic Lupus Erythematosus (SLE) and Neuropsychiatric SLE (NPSLE) has an estimated prevalence of 50% and 40%, respectively and both constitute major causes of death among SLE patients. In this review, a combined brain/heart Magnetic Resonance Imaging (MRI) for SLE risk stratification has been proposed.

The pathophysiologic background of NPSLE includes microangiopathy, macroscopic infarcts and accelerated atherosclerosis. Classic brain MRI findings demonstrate lesions suggestive of NPSLE in 50% of the NPSLE cases, while advanced MRI indices can detect pre-clinical lesions in the majority of them, but their clinical impact still remains unknown. Cardiac involvement in SLE includes myo-pericarditis, valvular disease/endocarditis, Heart Failure (HF), coronary macro-micro-vascular disease, vasculitis and pulmonary hypertension. Classic and advanced Cardiovascular Magnetic Resonance (CMR) indices allow function and tissue characterization for early diagnosis and treatment follow-up of CVD in SLE.

Although currently, there are no clinical data supporting the combined use of brain/heart MRI in asymptomatic SLE, it may have a place in cases with clinical suspicion of brain/heart involvement, especially in patients at high risk for CVD/stroke such as SLE with antiphospholipid syndrome (SLE/APS), in whom concurrent cardiac and brain lesions have been identified. Furthermore, it may be of value in SLE with multi-organ involvement, NPSLE with concurrent cardiac involvement, and recent onset of arrhythmia and/or heart failure.

Laboratory and Neuroimaging Biomarkers in Neuropsychiatric Systemic Lupus Erythematosus: Where Do We Stand, Where To Go?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by multi-systemic involvement. Nervous system involvement in SLE leads to a series of uncommon and heterogeneous neuropsychiatric (NP) manifestations. Current knowledge on the underlying pathogenic processes and their subsequent pathophysiological changes leading to NP-SLE manifestations is incomplete. Several putative laboratory biomarkers have been proposed as contributors to the genesis of SLE-related nervous system damage. Alongside the laboratory biomarkers, several neuroimaging tools have shown to reflect the nature of tissue microstructural damage associated with SLE, and thus were suggested to contribute to the understanding of the pathophysiological changes and subsequently help in clinical decision making. However, the number of useful biomarkers in NP-SLE in clinical practice is disconcertingly modest. In some cases it is not clear whether the biomarker is truly involved in pathogenesis, or the result of non-specific pathophysiological changes in the nervous system (e.g., neuroinflammation) or whether it is the consequence of a concomitant underlying abnormality related to SLE activity. In order to improve the diagnosis of NP-SLE and provide a better targeted care to these patients, there is still a need to develop and validate a range of biomarkers that reliably capture the different aspects of disease heterogeneity. This article critically reviews the current state of knowledge on laboratory and neuroimaging biomarkers in NP-SLE, discusses the factors that need to be addressed to make these biomarkers suitable for clinical application, and suggests potential future research paths to address important unmet needs in the NP-SLE field.

Magnetic resonance imaging in neuropsychiatric systemic lupus erythematosus: current state of the art and novel approaches

Systemic lupus erythematosus is a chronic, inflammatory, immune-mediated disease affecting 0.1% of the general population. Neuropsychiatric manifestations in systemic lupus erythematosus have been more frequently recognized and reported in recent years, occurring in up to 75% of patients during the disease course. Magnetic resonance imaging is known to be a useful tool for the detection of structural brain abnormalities in neuropsychiatric systemic lupus erythematosus patients because of the excellent soft-tissue contrast observed with MRI and the ability to acquire multiplanar images. In addition to conventional magnetic resonance imaging techniques to evaluate the presence of atrophy and white matter lesions, several different magnetic resonance imaging techniques have been used to identify microstructural or functional abnormalities. This review will highlight different magnetic resonance imaging techniques, including the advanced magnetic resonance imaging methods used to determine central nervous system involvement in systemic lupus erythematosus.

Hughes syndrome and epilepsy: when to test for antiphospholipid antibodies?

Epilepsy and seizures are reported among the neurological manifestations of antiphospholipid syndrome (APS) at a prevalence rate of approximately 8%, which is nearly 10 times the prevalence of epilepsy in the general population. The association of seizures with antiphospholipid antibodies (aPL) is even more significant in the presence of systemic lupus erythematosus (SLE). In this review, we discuss the epidemiological, pathophysiological, laboratory, clinical, and radiological aspects of this association, and derive suggestions on when to consider testing for aPL in epileptic patients and how to manage seizures secondary to APS based on literature data. Epilepsy due to APS should be considered in young patients presenting with seizures of unknown origin. Temporal lobe epilepsy seems to be particularly prevalent in APS patients. The pathogenesis is complex and may not only involve micro-thrombosis, but also a possible immune-mediated neuronal damage. Patients with seizures and positive aPL tend to develop thrombocytopenia and livedo racemosa more frequently compared with those without aPL. Magnetic resonance imaging (MRI) remains the imaging modality of choice in these patients. The presence of SLE and the presence of neurological symptoms significantly correlate with the presence of white matter changes on MRI. In contrast, the correlation between aPL positivity and the presence of white matter changes is very weak. Furthermore, MRI can be normal in more than 30–40% of neuropsychiatric lupus patients with or without aPL. aPL testing is recommended in young patients presenting with atypical seizures and multiple hyper-intensity lesions on brain MRI in the absence of other possible conditions. New MRI techniques can better understand the pathology of brain damage in neuro-APS. The therapeutic management of epileptic APS patients relies on anti-epileptic treatment and anticoagulant agents when there is evidence of a thrombotic event. In the absence of consensual recommendations, the decision of lifelong anticoagulation is discussed on a case-by-case basis. The anti-thrombotic benefit of hydroxychloroquine and statins is supported by several studies.

Proposed response criteria for neurocognitive impairment in systemic lupus erythematosus clinical trials

The objective of this study was to identify reliable and valid instruments to measure cognitive impairment in systemic lupus erythematosus (SLE), and to define minimally important change of cognitive impairment in SLE for clinical trials. Neurocognitive measures used in randomized clinical trials in SLE were reviewed, and response criteria were developed using consensus expert opinion. The definition of cognitive impairment in the ACR nomenclature for neuropsychiatric lupus syndrome was adopted. Cognitive impairment is a deficit of 2.0 or more standard deviations (SD) below the mean, compared to normative data, in the key domains of attention, memory and psychomotor speed. Cognitive decline is defined as a deficit of 1.5—1.9 SD below the mean. Focal decline is defined if impairment exists in one or more measures within one domain, and multifocal decline if impairment exists on measures spanning two or more domains. The combination of ACR neuropsychological battery and the Cognitive Symptoms Inventory (CSI) is recommended to quantitate cognitive function. A clinically important response is defined as an improvement of ≥ 1.0 SD with an effect size of 1.0 in the key domains of the ACR neuropsychological testing, and an improvement of ≥ 1.0 SD with an effect size of 1.0 in functional performance of the CSI. Lupus (2007) 16, 418—425

Quantitative magnetic resonance imaging in neuropsychiatric systemic lupus erythematosus

Neuropsychiatric symptoms are common in systemic lupus erythematosus (SLE) but are poorly understood.Although there is a wide spectrum of clinical manifestations, brain histologyoften simply shows a bland vasculopathy. Magnetic resonance techniques such as magnetic resonance spectroscopy, magnetization transfer imaging and diffusion weighted imaging have been used to try to improve our understandingof the pathophysiologicalmechanisms involved in neuropsychiatric lupus (NPSLE). This article reviews the current literature on the use of these techniques and their possible future role as diagnostic tools in NPSLE.

Advanced and Conventional Magnetic Resonance Imaging in Neuropsychiatric Lupus

Neuropsychiatric lupus is a major diagnostic challenge, and a main cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Magnetic resonance imaging (MRI) is, by far, the main tool for assessing the brain in this disease. Conventional and advanced MRI techniques are used to help establishing the diagnosis, to rule out alternative diagnoses, and recently, to monitor the evolution of the disease. This review explores the neuroimaging findings in SLE, including the recent advances in new MRI methods.

A multimodal MRI approach to identify and characterize microstructural brain changes in neuropsychiatric systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease with multi-organ involvement and results in neurological and psychiatric (NP) symptoms in up to 40% of the patients. To date, the diagnosis of neuropsychiatric systemic lupus erythematosus (NPSLE) poses a challenge due to the lack of neuroradiological gold standards. In this study, we aimed to better localize and characterize normal appearing white matter (NAWM) changes in NPSLE by combining data from two quantitative MRI techniques, diffusion tensor imaging (DTI) and magnetization transfer imaging (MTI). 9 active NPSLE patients (37 ± 13 years, all females), 9 SLE patients without NP symptoms (44 ± 11 years, all females), and 14 healthy controls (HC) (40 ± 9 years, all females) were included in the study. MTI, DTI and fluid attenuated inversion recovery (FLAIR) images were collected from all subjects on a 3 T MRI scanner. Magnetization transfer ratio (MTR), mean diffusivity (MD), fractional anisotropy (FA), radial diffusivity (RD), axial diffusivity (AD) maps and white matter lesion maps based on the FLAIR images were created for each subject. MTR and DTI data were then co-analyzed using tract-based spatial statistics and a cumulative lesion map to exclude lesions. Significantly lower MTR and FA and significantly higher AD, RD and MD were found in NPSLE compared to HC in NAWM regions. The differences in DTI measures and in MTR, however, were only moderately co-localized. Additionally, significant differences in DTI measures, but not in MTR, were found between NPSLE and SLE patients, suggesting that the underlying microstructural changes detected by MD are linked to the onset of NPSLE. The co-analysis of the anatomical distribution of MTI and DTI measures can potentially improve the diagnosis of NPSLE and contribute to the understanding of the underlying microstructural damage.

•

NAWM is investigated in NPSLE and SLE using MTI and DTI.

•

Differences in DTI and MTR between NPSLE and HC are widespread but only moderately co-localized.

•

Significant differences in MD between SLE and NPSLE suggest link to onset of NPSLE.

Blood-based candidate biomarkers of the presence of neuropsychiatric systemic lupus erythematosus in children

Objective

To examine select brain-reactive proteins for their usefulness to serve as blood-based biomarkers in the screening for neurocognitive deficits in childhood-onset systemic lupus erythematosus (cSLE-NCD).

Methods

Patients withcSLE (n=40) were studied longitudinally (month 1; month 18): working memory, psychomotor speed and visuoconstructional ability were assessed using formal neurocognitive testing to determine the presence of cSLE-NCD. Patients also completed the computerised Paediatric Automated Neuropsychological Assessment Metrics. The following brain-reactive proteins were measured in the blood: neutrophil gelatinase associated lipocalin (NGAL), S100B, S100A8/9, antibodies to NR2 glutamate receptor (aNR2-AB), ribosomal-P (aP-AB), glycoprotein-1 (aGP1-AB), and lupus anticoagulant.

Results

cSLE-NCD was present in 6 of 40 patients at baseline and 4 of 27 patients with 18-month information. aP-AB positivity was more commonly present with cSLE-NCD than without (p=0.05). aP-ABs were negatively associated with performance on tests assessing working memory, psychomotor speed and visuoconstructional ability in using formal neurocognitive testing. There were also significant negative associations between aP-AB, S100A8/9, aNR2-AB, aGP1-AB, and lupus anticoagulant and accuracy rates on select Paediatric Automated Neuropsychological Assessment Metrics subtests (p<0.05). Over time, decline in cognitive performance was more pronounced among patients with higher NGAL and aNR2-AB levels. Combinations of serum levels of S100A8/9, S100B, NGAL, aNR2-AB and aP-AB were able to identify cSLE-NCD (sensitivity: 100%; specificity 76%) in exploratory analysis.

Conclusions

Select brain-reactive proteins in the blood are associated with cognitive performance and the presence of cSLE-NCD, cross-sectionally and over time. This raises the possibility that testing of these proteins may assist with the screening of cSLE-NCD.

Demyelinating disease in SLE: is it multiple sclerosis or lupus?

Among the 12 systemic lupus erythematosus (SLE)-related central nervous system (CNS) syndromes defined by the American College of Rheumatology (ACR), demyelinating syndrome and myelopathy are two of the less prevalent and more poorly understood ones. One important issue concerning demyelinating disease in SLE is that it can be easily misdiagnosed with other central nervous system demyelinating disorders such as multiple sclerosis (MS). A clinically isolated neurological syndrome can be the presenting feature before other concomitant symptoms of SLE appear or definite MS is diagnosed. Although challenging, some diagnostic tests used in clinical practice and research may help to differentiate between these entities. These tests have improved the understanding of the pathogenesis in these diseases, but some points, such as the role of antiphospholipid antibodies in SLE-associated transverse myelitis, remain unclear and are a matter of ongoing debate. This review discusses clinical, pathophysiological, radiological and therapeutic concepts of demyelinating disease of the CNS in SLE, focussing on its differentiation from MS and its relation with other CNS demyelinating processes, such as transverse myelitis, optic neuritis and neuromyelitis optica.

Chorea, a little-known manifestation in systemic lupus erythematosus: short literature review and four case reports

Chorea is a movement disorder that may be found in children due to several causes. Here we focus especially on Systemic Lupus Erythematosus associated chorea. First we outline its epidemiology, hypothesized pathogenesis, clinical presentation and treatment, then we report four significant clinical cases, which represent well the extreme variability of set of symptoms that may accompany lupus chorea. Our experience, according to literature, suggests that choreic movements in a child should alert the pediatrician and lead him to investigate a potential neurological involvement of Systemic Lupus Erythematosus.

Diffusion tensor imaging in neuropsychiatric systemic lupus erythematosus

Background

Neuropsychiatric systemic lupus erythematosus (NPSLE) is associated with increased morbidity and mortality.

Methods

We used Diffusion Tensor Imaging (DTI) to assess white matter abnormalities in seventeen NPSLE patients, sixteen SLE patients without NPSLE, and twenty age- and gender-matched controls.

Results

NPSLE patients differed significantly from SLE and control patients in white matter integrity of the body of the corpus callosum, the left arm of the forceps major and the left anterior corona radiata.

Conclusions

Several possible mechanisms of white matter injury are explored, including vascular injury, medication effects, and platelet or fibrin macro- or microembolism from Libman-Sacks endocarditis.

Neurocognitive impairment in children and adolescents with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease, in which neuropsychiatric manifestations are a common cause of significant morbidity. The American College of Rheumatology has identified 19 distinct neuropsychiatric syndromes associated with SLE, although the 1982 American College of Rheumatology classification criteria for SLE recognize only two: seizures and psychosis. Neurocognitive impairment (NCI) is one of the most common and clinically challenging manifestations of SLE, but its pathophysiology remains poorly understood. This Review examines the epidemiology and pathophysiology of NCI in children and adolescents with SLE, as well as the diagnostic and therapeutic approaches that are available for these patients. As few published studies specifically address NCI in pediatric SLE, new directions for research are also discussed.

Quantifying subclinical central nervous lesions in primary antiphospholipid syndrome: the role of magnetization transfer imaging

PURPOSE

To define the role of magnetization transfer imaging (MTI) in detecting subclinical central nervous system (CNS) lesions in primary antiphospholipid syndrome (PAPS).

MATERIALS AND METHODS

Ten non-CNS PAPS patients were compared to 10 CNS PAPS patients and 10 age- and sex-matched controls. All PAPS patients met Sapporo criteria. All subjects underwent conventional MRI and complementary MTI analysis to compose histograms. CNS viability was determined according to the magnetization transfer ratio (MTR) by mean pixel intensity (MPI) and the mean peak height (MPH). Volumetric cerebral measurements were assessed by brain parenchyma factor (BPF) and total/cerebral volume.

RESULTS

MTR histograms analysis revealed that MPI was significantly different among groups (P < 0.0001). Non-CNS PAPS had a higher MPI than CNS PAPS (30.5 +/- 1.01 vs. 25.1 +/- 3.17 percent unit (pu); P < 0.05) although lower than controls (30.5 +/- 1.01 vs. 31.20 +/- 0.50 pu; P < 0.05). MPH in non-CNS PAPS (5.57 +/- 0.20% (1/pu)) was similar to controls (5.63 +/- 0.20% (1/pu), P > 0.05) and higher than CNS PAPS (4.71 +/- 0.30% (1/pu), P < 0.05). A higher peak location (PL) was also observed in the CNS PAPS group in comparison with the other groups (P < 0.0001). In addition, a lower BPF was found in non-CNS PAPS compared to controls (0.80 +/- 0.03 vs. 0.84 +/- 0.02 units; P < 0.05) but similar to CNS PAPS (0.80 +/- 0.03 vs. 0.79 +/- 0.05 units; P > 0.05).

CONCLUSION

Our findings suggest that non-CNS PAPS patients have subclinical cerebral damage. The long-termclinical relevance of MTI analysis in these patients needs to be defined by prospective studies.

Neuropsychological impairment in systemic lupus erythematosus: a comparison with multiple sclerosis

In this manuscript, we review literature describing the neuropsychological and brain imaging characteristics of systemic lupus erythematosus (SLE) patients. The findings are compared and contrasted with multiple sclerosis (MS) studies, revealing similarities and differences of interest to clinicians and researchers. While cognitive impairment is somewhat less common in SLE than MS, the diseases share a similar cognitive profile with deficits most prominent on tests emphasizing the speed of information processing, working memory, and visual/spatial learning, and memory. In early or more mildly affected patients, diffuse white matter damage, which may not be apparent on conventional brain imaging, plays a major role in clinical presentation and cognitive testing. The causes of white matter damage are very different, however, and in later stages of the disease MS and SLE appear to give rise to different forms of cerebral pathology. MS may be characterized by increasing brain atrophy affecting especially the cortical and deep gray matter, at least after conversion to secondary progressive course. There is less evidence for neurodegenerative changes in SLE, but patients are increasingly at risk for cerebrovascular disease. We conclude by offering some suggestions for future clinical and imaging research.

Brain diffusivity in patients with neuropsychiatric systemic lupus erythematosus with new acute neurological symptoms

PURPOSE

To investigate the source of significant difference in apparent diffusion coefficient (ADC) between patients with acute symptoms of neuropsychiatric (NP) systematic lupus erythematosus (SLE) (NPSLE) and normal controls.

MATERIALS AND METHODS

Diffusion-weighted echo-planar imaging was performed on 1.5-T scanners in 17 female and four male NPSLE patients with acute neurological symptoms (23-76 years, mean = 42.7 years), and in 21 aged-matched healthy controls (16 female, five male, 26-63 years, mean = 41.1 years). ADC histograms were calculated for whole brain, gray matter tissue, and white matter tissue.

RESULTS

Of the 17 NPSLE patients, 13 (72%) had abnormal findings on MR imaging. The NPSLE patients had a mean ADC value of (1105.1 +/- 23.6) x 10(-6) mm(2)/second and the control had a mean ADC value of (1012.5 +/- 9.4) x 10(-6) mm(2)/second (P < or = 0.0012). Significant differences were also found in white matter (P < or = 0.0020) and gray matter (P < or = 0.0022).

CONCLUSION

ADC histogram analysis demonstrated increased general diffusivity in the brain in NPSLE patients with acute symptoms compared with healthy normal controls. This finding suggests that in the brain parenchyma of NPSLE patients a loss of tissue integrity occurs facilitating motility of free-water protons.

Magnetization transfer magnetic resonance imaging of the brain, spinal cord, and optic nerve

Magnetic resonance imaging is highly sensitive in revealing CNS abnormalities associated with several neurological conditions, but lacks specificity for their pathological substrates. In addition, MRI does not allow evaluation of the presence and extent of damage in regions that appear normal on conventional MRI sequences and that postmortem studies have shown to be affected by pathology. Quantitative MR-based techniques with increased pathological specificity to the heterogeneous substrates of CNS pathology have the potential to overcome such limitations. Among these techniques, one of the most extensively used for the assessment of CNS disorders is magnetization transfer MRI (MT-MRI). The application of this technique for the assessment of damage in macroscopic lesions, in normal-appearing white and gray matter, and in the spinal cord and optic nerve of patients with several neurological conditions is providing important in vivo information-dramatically improving our understanding of the factors associated with the appearance of clinical symptoms and the accumulation of irreversible disability. MT-MRI also has the potential to contribute to the diagnostic evaluation of several neurological conditions and to improve our ability to monitor treatment efficacy in experimental trials.

Detection of change in CNS involvement in neuropsychiatric SLE: a magnetization transfer study

PURPOSE

To assess whether magnetization transfer imaging (MTI) parameters change in correspondence with clinical changes in NPSLE patients.

MATERIALS AND METHODS

Nineteen female patients (mean age=37.5 years, range=19-64) underwent MTI on at least two separate occasions (mean time between scans=25.4 months, range=5.4-52.3 months). Twenty-four pairs of scans of 19 patients were available. Each patient's clinical course was classified as improved, stable, or deteriorated. Whole-brain magnetization transfer ratio (MTR) histograms were generated. The peak height of these histograms was used as an estimate of parenchymal integrity. Based on the change in clinical status, paired examinations were grouped and tested for significant differences between the first and second examinations using paired-samples t-tests.

RESULTS

Four patients clinically deteriorated, all patients showed a significant peak height decrease (mean decrease=8.6%, P=0.02), and in 14 patients with stable disease the peak height did not change significantly (mean increase=0.4%). Six patients clinically improved, and all showed a significant relative peak height increase (mean increase=12.0%, P=0.02).

CONCLUSION

The peak height of whole-brain MTR histograms corresponds to changes in the clinical status of individual NPSLE patients. This suggests that MTI can be a valuable tool in the clinical assessment of such patients.

Sources of variation in multi-centre brain MTR histogram studies: body-coil transmission eliminates inter-centre differences

OBJECT

1. Identify sources of variation affecting Magnetisation Transfer Ratio (MTR) histogram reproducibility between-centres. 2. Demonstrate complete elimination of inter-centre difference.

MATERIALS AND METHODS

Six principle sources of variation were summarised and analysed. These are: the imager coil used for radiofrequency (RF) transmission, imager stability, the shape and other parameters describing the Magnetisation Transfer (MT) pulse, the MT sequence used (including its parameters), the image segmentation methodology, and the histogram generation technique. Transmit field nonuniformity and B1 errors are often the largest factors. PLUMB (Peak Location Uniformity in MTR histograms of the Brain) plots are a convenient way of visualising differences. Five multi-centres studies were undertaken to investigate and minimise differences.

RESULTS

Transmission using a body coil, with a close-fitting array of surface coils for reception, gave the best uniformity. Differences between two centres, having MR imagers from different manufacturers, were completely eliminated by using body coil excitation, making a small adjustment to the MT pulse flip angle, and carrying out segmentation at a single centre. Histograms and their peak location and height values were indistinguishable.

CONCLUSIONS

Body coil excitation is preferred for multi-centre studies. Analysis (segmentation and histogram generation) should ideally be carried out at a single site.

Association between microscopic brain damage as indicated by magnetization transfer imaging and anticardiolipin antibodies in neuropsychiatric lupus

The pathogenetic role of anticardiolipin antibodies (aCLs) in patients with neuropsychiatric systemic lupus erythematosus (NPSLE) without cerebral infarcts remains elusive. Magnetization transfer imaging (MTI) has proved to be a sensitive tool for detecting diffuse microscopic brain damage in NPSLE patients. In this study we examined the correlation between grey and white matter magnetization transfer ratio (MTR) parameters and the presence of IgM and IgG aCLs and lupus anticoagulant in 18 patients with systemic lupus erythematosus and a history of NPSLE but without cerebral infarcts on conventional magnetic resonance imaging. Lower grey matter mean MTR (P < 0.05), white matter mean MTR (P < 0.05), white matter peak location (P < 0.05) and grey matter peak location (trend toward statistical significance) were observed in IgM aCL-positive patients than in IgM aCL-negative patients. No significant differences were found in MTR histogram parameters with respect to IgG aCL and lupus anticoagulant status, nor with respect to anti-dsDNA or anti-ENA (extractable nuclear antigen) status. This is the first report of an association between the presence of aCLs and cerebral damage in grey and white matter in NPSLE. Our findings suggest that aCLs are associated with diffuse brain involvement in NPSLE patients.

Imaging in CNS lupus

The diagnosis of neuropsychiatric systemic lupus erythematosus (NPSLE) is complex not only on account of the heterogeneous nature of neurological presentation but also because of the difficulty of differentiating lupus-related pathology from other neuropsychiatric diseases. Magnetic resonance imaging (MRI) remains the gold standard for the non-invasive assessment of NPSLE but there are problems, both with sensitivity and specificity. Both T(2) quantitation and the use of gadolinium have shown promise in differentiating acute from chronic lesions. Nonetheless, the lack of sensitivity of conventional MRI has led to the exploration of other MR-based techniques. Magnetic resonance spectroscopy (MRS) allows the measurement of brain metabolites, whereas diffusion weighted imaging and diffusion tensor imaging allow assessment of white matter structure and integrity. MRS studies in NPSLE have consistently shown a reduction in N-acetyl aspartate (a neuronal marker). Diffusion weighted imaging has had only limited application in lupus and the results to date have shown abnormal diffusivity in lupus patients consistent with inflammation and loss of white matter structure. These techniques remain research tools at this early stage. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) have also been explored as functional imaging tools in lupus and both appear to be more sensitive in detecting subtle brain changes in NPSLE but there are issues with specificity which deter their use in the clinical setting.

Management of neuropsychiatric lupus

Nervous system disease in systemic lupus erythematosus (SLE) is manifested by a wide variety of clinical manifestations. Despite the development of a universal classification for neuropsychiatric (NP) lupus in 1999, there continues to be considerable variability in the reported prevalence of NP syndromes between different lupus cohorts. Due to the lack of specificity of individual NP manifestations, non-SLE causes such as complications of therapy and co-morbidities must be considered in advance of attributing the event to one or more primary immunopathogenic mechanisms. These include intracranial microangiopathy, autoantibodies to neuronal and non-neuronal antigens, and the generation of proinflammatory cytokines and mediators. The diagnosis of NP-SLE remains largely one of exclusion and is approached in individual patients by thorough clinical evaluation, supported when necessary by autoantibody profiles, diagnostic imaging, electrophysiologic studies and objective assessment of cognitive performance. Given the diversity in clinical manifestations, the management is tailored to the specific needs of individual patients. In the absence of controlled studies, the use of symptomatic therapies, immunosuppressives, anticoagulants and non-pharmacologic interventions is supported by case series and clinical experience.

Neuropsychiatric Lupus

Nervous system disease in patients who have systemic lupus erythematosus (SLE) spans a wide spectrum of neurologic (N) and psychiatric (P) features that may be attributed to a primary manifestation of SLE, complications of the disease or its therapy, or a coincidental disease process. The etiology of primary NP disease is multifactorial and includes vascular injury of intracranial vessels, autoantibodies to neuronal antigens, ribosomes and phospholipid-associated proteins, and the intracranial generation of cytokines. In the absence of a diagnostic gold standard for most of the NP-SLE syndromes, a range of investigations are employed to support the clinical diagnosis and determine the severity of NP disease. Treatment remains largely empiric in the absence of controlled studies, and current strategies include the use of immunosuppressive therapies, appropriate symptomatic interventions, and the treatment of non-SLE factors.

Central nervous system disease in primary Sjögren’s syndrome: The role of magnetic resonance imaging

OBJECTIVES

To examine the frequency of central nervous system (CNS) disease in primary Sjogrens syndrome (pSS) and indicate ways in which cerebral magnetic resonance imaging (MRI) may help determine the significance of CNS involvement.

METHODS

The current review was based on a Medline (Pubmed) literature search through May 2003, focused on Sjogrens syndrome, other vasculitides, multiple sclerosis (MS), specific MRI techniques, and MRI findings with regard to the above-mentioned diseases. Additional literature was identified in the reference sections of articles listed in Medline.

RESULTS

Severe CNS manifestations reminiscent of MS have been described in pSS patients. Moreover, the prevalence of nonfocal neuropsychological abnormalities has been found to be elevated in some pSS patient populations. MRI studies suggest discrete cerebral tissue damage even in neurologically asymptomatic patients. However, small white matter lesions are nonspecific and may be related to age or cerebrovascular risk factors such as hypertension. A large controlled study, complementing established T2-weighted MRI with fluid-attenuated inversion recovery (FLAIR) to achieve high sensitivity in lesion detection, could indicate the disease specificity of white matter lesions in pSS. Newer MR techniques, such as spectroscopy and magnetization transfer imaging, applied, for example, in MS and systemic lupus erythematosus (SLE) to evaluate CNS tissue injury, could help determine the extent and mechanisms of macroscopic and microscopic CNS lesions in pSS.

CONCLUSIONS

Future controlled studies will be necessary to more precisely estimate the prevalence of CNS lesions in pSS, specifically of discrete white matter abnormalities. Newer MRI techniques have the potential to provide information on the severity and pathophysiological mechanisms of CNS tissue damage.

Multisequence magnetic resonance imaging study of neuropsychiatric systemic lupus erythematosus

OBJECTIVE

To investigate the relationship between magnetization transfer imaging (MTI), diffusion-weighted imaging (DWI), proton magnetic resonance spectroscopy (H-MRS), and T2 relaxometry findings in patients with primary neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

The study group consisted of 24 female patients (mean age 36 years [range 23-65]) who had had a variety of neuropsychiatric symptoms that were judged to be due to NPSLE according to the criteria of the American College of Rheumatology. Patients with current active disease were excluded from participation. Quantitative MTI, DWI, H-MRS, and T2 relaxometry data were acquired in all patients, and the correlation coefficients were calculated.

RESULTS

MTI results reflecting a decrease in homogeneity of cerebral parenchyma correlated significantly with H-MRS results representing axonal damage. MTI results also correlated significantly with DWI results reflecting increased diffusivity in the cerebral parenchyma. Finally, MTI results reflecting decreased cerebral homogeneity correlated significantly with increased T2 relaxation time, associated with either edema or gliosis. Increased T2 relaxation time correlated significantly with DWI results reflecting increased diffusivity. With the exception of the correlation between H-MRS and MTI findings, there was no significant correlation between H-MRS results and any other parameter.

CONCLUSION

The selected study parameters represent different biologic features in the human brain and can be informative with regard to different pathologic processes in NPSLE. The demonstrated associations between MTI, DWI, H-MRS, and T2 data in patients with a history of NPSLE suggest that there is one pathogenesis and/or common neuropathologic outcome in NPSLE despite differences in clinical presentation.

Selective gray matter damage in neuropsychiatric lupus

OBJECTIVE

Damage of brain parenchyma in patients with primary diffuse neuropsychiatric systemic lupus erythematosus (NPSLE) has been indicated by magnetization transfer imaging (MTI). However, the location of MTI abnormalities is unknown. This study was undertaken to assess the distribution of MTI abnormalities over gray matter (GM) and white matter (WM) in SLE patients with a history of NP symptoms without explanatory magnetic resonance imaging (MRI) evidence of focal disease.

METHODS

MTI was performed in 24 female SLE patients with a history of diffuse NP symptoms and 24 healthy female controls. Magnetization transfer ratio (MTR) maps were calculated for GM and WM separately, and GM and WM MTR histograms were generated. Univariate and multivariate analyses with age as an additional covariate were performed on the histogram parameters peak location (PL), peak height (PH), and mean MTR.

RESULTS

Compared with controls, significantly reduced PH (mean +/- SD 136 +/- 22 arbitrary units versus 151 +/- 13 arbitrary units) and mean MTR (33.3 +/- 1.0 percent units versus 33.6 +/- 0.5 percent units) were found in the GM of NPSLE patients (P = 0.002 and P = 0.033, respectively, in multivariate analyses). No significant differences were observed for WM MTR parameters.

CONCLUSION

This is the first study to demonstrate, using MTI, that in SLE patients with a history of NP symptoms and without explanatory focal abnormalities on MRI, the GM is particularly affected. These findings support the hypothesis that neuronal injury may underlie central nervous system manifestations in NPSLE.

Magnetization transfer MRI in multiple sclerosis and other central nervous system disorders

The present review summarizes the major contributions given by magnetization transfer-magnetic resonance imaging to provide an accurate in vivo picture of the heterogeneity of central nervous system pathology and, ultimately, to improve our ability to monitor the evolution of various neurological conditions.

Dementia and ageing

Sophisticated imaging techniques are required to characterise the complex dynamic neuro-anatomical changes that occur over time in health and disease. With the advent of potential therapies for the treatment of degenerative dementias, imaging strategies need to enable early diagnosis and facilitate monitoring of disease progression in treatment trials. This chapter highlights some of the innovative structural and functional imaging techniques that have impacted on the clinical management of Alzheimer's disease.

Association of global brain damage and clinical functioning in neuropsychiatric systemic lupus erythematosus

OBJECTIVE

To investigate the relationship between quantitative estimates of global brain damage based on magnetization transfer imaging (MTI) and cerebral functioning, as measured by neurologic, psychiatric, and cognitive assessments, as well as disease duration in patients with a history of neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

In a clinically heterogeneous group of 24 female patients (age range 19-65 years, mean age 35 years) with a history of NPSLE, the correlation values of several volumetric MTI measures and an estimate of cerebral atrophy, neurologic functioning (Kurtzke's Expanded Disability Status Scale [EDSS]), psychiatric functioning (the Hospital Anxiety and Depression Scale [HADS]), and cognitive functioning (cognitive impairment score [CIS] derived from the revised Wechsler Adult Intelligence Scale), as well as several measures of disease duration were assessed using Pearson's correlation coefficient.

RESULTS

Quantitative volumetric estimates of global brain damage based on MTI and a measure of global brain atrophy correlated significantly with the EDSS, HADS, and CIS scores. No significant correlation was found between the quantitative estimates of global brain damage and the measures of disease duration.

CONCLUSION

The results of this study demonstrate that volumetric MTI parameters and cerebral atrophy reflect functionally relevant brain damage in patients with NPSLE. Furthermore, the absence of a linear relationship between disease duration and results of volumetric MTI measures and atrophy suggests a complicated pattern of accumulating brain damage in patients with NPSLE.

Magnetization transfer imaging in normal aging, mild cognitive impairment, and Alzheimer's disease

The purpose of this study was to assess whether structural brain damage as detected by volumetric magnetization transfer imaging (MTI) is present in mild cognitive impairment (MCI) and Alzheimer's disease (AD) and, if so, whether these abnormalities are global in character or restricted to the temporal lobe. Volumetric MTI analysis of the whole brain and temporal and frontal lobes was performed in 25 patients with probable AD, in 13 patients with MCI, and in 28 controls. Magnetization transfer ratio (MTR) histograms were produced, from which we derived measures for structural brain damage and atrophy. The peak heights of the MTR histograms of MCI and AD patients were lower than those of controls for the whole brain and temporal and frontal lobes, reflecting structural brain damage. AD patients had more atrophy than controls in all regions that were studied. MCI patients differed from controls for temporal lobe atrophy only. Volumetric MTI demonstrates structural changes that are related to cognitive decline in large parts of the brain of AD patients. Moreover, structural changes also were observed in MCI patients, indicating that widespread brain damage can be demonstrated before patients are clinically demented.

Systemic lupus erythematosus: diagnostic application of magnetization transfer ratio histograms in patients with neuropsychiatric symptoms--initial results

PURPOSE

To explore the diagnostic potential of magnetization transfer ratio (MTR) histogram analysis in patients with neuropsychiatric systemic lupus erythematosus (SLE) by using multivariate discriminant analysis (MDA).

MATERIALS AND METHODS

Volumetric magnetization transfer imaging was performed in nine patients with active non-thromboembolic, neuropsychiatric SLE, 10 patients with SLE who had had neuropsychiatric SLE previously, 10 patients with SLE but no history of neuropsychiatric SLE, 10 patients with inactive multiple sclerosis, and 10 healthy control subjects. For each subject, an MTR histogram of the whole brain was generated, and an MDA score was produced for each histogram. Each patient was assigned to a clinical subgroup on the basis of these MDA scores. For assignment, binary comparisons between subgroups were made. The accuracy of this classification method was assessed and compared with that of conventional MTR histogram analysis.

RESULTS

With MDA, the success rate of binary classification was 60%-100%, depending on which two groups were compared. When the different clinical subgroups were separated, MDA parameters were always better than conventional MTR histogram parameters, with P values ranging from.05 to less than 1 x 10(-6) of those attained with the best conventional parameter.

CONCLUSION

With MDA, MTR histograms of brain tissue may provide diagnostic information for individual patients in the clinical context of SLE.

Systemic lupus erythematosus and antiphospholipid syndrome in children and adolescents

Systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) can be associated with significant morbidity in children and adolescents. Renal involvement in SLE appears to be more severe and more frequent in the pediatric age group, with the major predictors for poor outcome being the severity of histopathologic lesions, severity of renal impairment at diagnosis, and hypertension. In addition to currently recognized cardiovascular and pulmonary involvement, accelerated atherosclerosis is of increasing concern in young individuals with SLE, because of both disease effects and medication usage. Neuropsychiatric SLE seen in childhood ranges from subtle cognitive dysfunction to severe central nervous system involvement; however, there is controversy over the value of different diagnostic studies. APS in children may be associated with SLE, idiopathic, or associated with viral infections. Systemic anticoagulation is recommended for patients with thrombotic events, but long-term management has not been well studied in children.

Imaging modalities in central nervous system systemic lupus erythematosus

Within the past few years, a clearly defined case definition system for central nervous system systemic lupus erythematosus (CNS-SLE) has been established. This has allowed cross-study comparisons of patients fulfilling the specific case definitions. New imaging techniques used on the subgroup of CNS-SLE patients that did not have any evidence for infarctions suggest that in these patients symptoms are associated with a diffuse process in the brain. Most likely this process leads to axonal damage and demyelination, ultimately leading to cerebral atrophy. With respect to the diagnostic work-up of SLE patients with neuropsychiatric symptoms, it has become clear that cranial magnetic resonance imaging is the technique of choice. Preliminary studies using quantitative magnetic resonance imaging techniques suggest that patients with neuropsychiatric symptoms caused by active CNS-SLE can be differentiated from patients with the same symptoms caused by residual disease.