Proton MR spectroscopy in clinically isolated syndromes suggestive of multiple sclerosis

Early metabolic alterations in the normal‑appearing grey and white matter of patients with clinically isolated syndrome suggestive of multiple sclerosis: A proton MR spectroscopic study

Proton magnetic resonance spectroscopy (¹H-MRS) is an advanced method of examining metabolic profiles. The present study aimed to assess in vivo metabolite levels in areas of normal-appearing grey (thalamus) and white matter (centrum semiovale) using ¹H-MRS in patients with clinically isolated syndrome (CIS) suggestive of multiple sclerosis and compare them to healthy controls (HCs). Data from 35 patients with CIS (CIS group), of which 23 were untreated (CIS-untreated group) and 12 were treated (CIS-treated group) with disease-modifying-therapies (DMTs) at the time of ¹H-MRS, and from 28 age- and sex-matched HCs were collected using a 3.0 T MRI and single-voxel ¹H-MRS (point resolved spectroscopy sequence; repetition time, 2,000 msec; time to echo, 35 msec). Concentrations and ratios of total N-acetyl aspartate (tNAA), total creatine (tCr), total choline (tCho), myoinositol, glutamate (Glu), glutamine (Gln), Glu + Gln (Glx) and glutathione (Glth) were estimated in the thalamic-voxel (th) and centrum semiovale-voxel (cs). For the CIS group, the median duration from the first clinical attack to ¹H-MRS was 102 days (interquartile range, 89.5.-131.5). Compared with HCs, significantly lower Glx(cs) (P=0.014) and ratios of tCho/tCr(th) (P=0.026), Glu/tCr(cs) (P=0.040), Glx/tCr(cs) (P=0.004), Glx/tNAA(th) (P=0.043) and Glx/tNAA(cs) (P=0.015) were observed in the CIS group. No differences in tNAA levels were observed between the CIS and the HC groups; however, tNAA(cs) was higher in the CIS-treated than in the CIS-untreated group (P=0.028). Compared with those in HC group, decreased Glu(cs) (P=0.019) and Glx(cs) levels (P=0.014) and lower ratios for tCho/tCr(th) (P=0.015), Gln/tCr(th) (P=0.004), Glu/tCr(cs) (P=0.021), Glx/tCr(th) (P=0.041), Glx/tCr(cs) (P=0.003), Glx/tNAA(th) (P=0.030) and Glx/tNAA(cs) (P=0.015) were found in the CIS-untreated group. The present findings showed alterations in the normal-appearing grey and white matter of patients with CIS; moreover, the present results suggested an early indirect treatment effect of DMTs on the brain metabolic profile of these patients.

Creatine and multiple sclerosis

Multiple sclerosis (MS) is a complex and debilitating neurodegenerative disease, with unknown cause(s), unpredictable prognosis, and rather limited treatment options. MS is often accompanied by various metabolic disturbances, with impaired creatine metabolism may play a role in its pathogenesis and the clinical course of the disease. This review summarizes human trials describing alterations in creatine levels in the nervous system and other tissues during MS, affects how certain medications for MS affect brain creatine concentrations, and discusses a possible demand for exogenous creatine as an adjunct therapeutic agent in the management of MS. Creatine metabolism seems to be dysfunctional in MS, indicating a low metabolic state of the brain and other relevant organs in this unpredictable demyelinating disease. A disease-driven brain creatine deficit could be seen as a distinctive pathological facet of severe MS that might be approached with targeted therapies in aim to restore creatine homeostasis.

Quantifying the Metabolic Signature of Multiple Sclerosis by in vivo Proton Magnetic Resonance Spectroscopy: Current Challenges and Future Outlook in the Translation From Proton Signal to Diagnostic Biomarker

Proton magnetic resonance spectroscopy (¹H-MRS) offers a growing variety of methods for querying potential diagnostic biomarkers of multiple sclerosis in living central nervous system tissue. For the past three decades, ¹H-MRS has enabled the acquisition of a rich dataset suggestive of numerous metabolic alterations in lesions, normal-appearing white matter, gray matter, and spinal cord of individuals with multiple sclerosis, but this body of information is not free of seeming internal contradiction. The use of ¹H-MRS signals as diagnostic biomarkers depends on reproducible and generalizable sensitivity and specificity to disease state that can be confounded by a multitude of influences, including experiment group classification and demographics; acquisition sequence; spectral quality and quantifiability; the contribution of macromolecules and lipids to the spectroscopic baseline; spectral quantification pipeline; voxel tissue and lesion composition; T₁ and T₂ relaxation; B₁ field characteristics; and other features of study design, spectral acquisition and processing, and metabolite quantification about which the experimenter may possess imperfect or incomplete information. The direct comparison of ¹H-MRS data from individuals with and without multiple sclerosis poses a special challenge in this regard, as several lines of evidence suggest that experimental cohorts may differ significantly in some of these parameters. We review the existing findings of in vivo¹H-MRS on central nervous system metabolic abnormalities in multiple sclerosis and its subtypes within the context of study design, spectral acquisition and processing, and metabolite quantification and offer an outlook on technical considerations, including the growing use of machine learning, by future investigations into diagnostic biomarkers of multiple sclerosis measurable by ¹H-MRS.

Molecular and Metabolic Imaging in Multiple Sclerosis

Multiple sclerosis is a multifactorial disease with heterogeneous pathogenetic mechanisms, which deserve to be studied to evaluate new possible targets for treatments and improve patient management. MR spectroscopy and PET allow assessing in vivo the molecular and metabolic mechanisms underlying the pathogenesis of multiple sclerosis. This article focuses on the relationship between these imaging techniques and the biologic and chemical pathways leading to multiple sclerosis pathology and its clinical features. Future directions of research are also presented.

Metabolic changes in normal appearing white matter in multiple sclerosis patients using multivoxel magnetic resonance spectroscopy imaging

Demyelination and axonal degeneration caused by multiple sclerosis (MS) exist in the white matter and not only in the lesion area. Magnetic resonance spectroscopy (MRS) could provide a unique insight into metabolic changes in the normal appearing white matter (NAWM). To evaluate the subtle axonal degeneration and delineate the spatial distribution of metabolite abnormalities in the NAWM in patients with MS. A total of 17 clinically definite relapsing-remitting MS (RRMS) patients and 21 healthy controls were enrolled in this study. 2D 1H magnetic resonance spectroscopic imaging (MRSI) performed at 3 Tesla was used to measure metabolite concentrations in the frontal-parietal-occipital NAWM. Ratios of N-acetyl-aspartate (NAA) and choline (Cho) to creatine (Cr) and Cho to NAA were calculated in each voxel. MS patients showed decreased NAA/Cr and increased Cho/NAA ratios in the NAWM compared to healthy controls. In the parietal NAWM, the extent of NAA/Cr decrease was significantly higher than that in the frontal and parietal-occipital NAWM. Decreased NAA in the NAWM would provide useful metabolic information for evaluation of disease progression in MS. The high extent of NAA decrease in the parietal NAWM helps improve the accuracy of the prediction.

Cerebrospinal fluid levels of brain specific proteins in optic neuritis

This study evaluates levels of cerebrospinal fluid (C SF) brain-specific proteins (BSP) in subjects with optic neuritis (O N) who are at high risk of progression to multiple sclerosis (MS). Forty-one subjects had acute O N and 17 subjects with other neurological diseases (OND) served as controls. Twenty-o ne subjects with O N had white matter lesions on magnetic resonance imaging (MRI) and intrathecal synthesis of oligoclonal IgG bands (OB) consistent with being at high risk of progression to MS; eight of whom later were diagnosed with clinically definite MS (C DMS). Levels of S100B, ferritin and two neurofilament heavy chain phosphoforms (NfHSMI34 and NfHSMI35) were analysed using ELISA technique. A putative index of ‘axonal health’ was expressed as a ratio of NfHSMI34 to NfHSMI35. NfHSMI34 and the NfHSMI34:SMI35 were significantly elevated in subjects with O N compared to controls. No significant differences in levels of C SF BSP were seen between O N subjects with C DMS plus those at high risk of progression to MS and O N subjects with normal MRI and negative C SF analysis. In conclusion, there is evidence of axonal damage in subjects who present with O N, which is independent of the diagnosis of C DMS.

MRI/MRS of corpus callosum in patients with clinically isolated syndrome suggestive of multiple sclerosis

A trophy of corpus callosum (C C) related to axonal loss has previously been observed in patients at the early stage of clinically definite multiple sclerosis (CDMS). Atrophy increases with the progression of the disease. Nevertheless, no data concerning the onset of atrophy of C C are currently available. The purpose of this study is to determine if damage in callosal tissue was present at the earliest stage of MS, in a subgroup of patients presenting with a clinically isolated syndrome suggestive of MS (C ISSMS), fulfilling the dissemination in space criteria according to McDonald. Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) techniques were applied to measure C C volume, magnetization transfer ratio (MTR), mean diffusivity (MD), N-acetyl aspartate/choline-containing compounds (NAA/C ho) ratio, N-acetyl aspartate/total creatine (NA A/C r) ratio and C ho/C r ratio inside the C C of 46 C ISSMS patients and 24 sexand age-matched controls. No atrophy of C C was observed in the C ISSMS group. C C of patients was character ized by decreased MTR and increased MD. No change in the NA A/C r ratio was observed while the NA A/C ho ratio decreased and C ho/C r ratio increased in the splenium and the central anterio r part of C C. These abnormalities were present in patients with, but also without, macroscopic lesions inside the C C. O ur results indicate that diffuse structural and metabolic changes, which may be interpreted as representing predominantly myelin patho logy, occur in the C C at the earliest stage of MS before any atrophy is detected.

Onset and underpinnings of white matter atrophy at the very early stage of multiple sclerosis - a two-year longitudinal MRI/MRSI study of corpus callosum

Backgrounds Atrophy of corpus callosum (CC), a white matter structure linking the two hemispheres, is commonly observed in multiple sclerosis (MS). However, the occurrence and processes leading to this alteration are not yet determined.

Goal and methods To better characterize the onset and progression of CC atrophy from the early stage of MS, we performed a two-year follow-up magnetic resonance imaging/magnetic resonance spectroscopic imaging (MRI/MRSI) exploration of CC in 24 patients with clinically isolated syndrome. These patients were explored using the same protocol at month (M)6, M12 and M24. MRI/MRSI techniques were applied to measure CC volume, and relative concentrations of N-acetylaspartate (NAA), creatine/phosphocreatine (Cr) and choline-containing compounds (Cho). A group of matched controls was also explored.

Results Atrophy of CC, not present at baseline, was observed at M12 and progressed over the second year (M24). At baseline, a decrease in relative NAA level was observed in the anterior and posterior body of CC, with normalization during the follow-up period. In the anterior body, an increase in relative Cho level was observed, with normalization at M6. Normal relative Cr levels were observed at all time points in all sub-regions. The rate of CC atrophy was correlated with the change in the Expanded Disability Status Scale (EDSS) during the follow-up period.

Conclusion These results suggest that CC atrophy appears over a period of one year after the first acute inflammatory episode, and that this atrophy is accompanied, especially in the anterior body of CC, by a normalization of the relative Cho levels, marker of acute inflammation, and NAA levels, marker of neuronal dysfunction and/or loss.

Increased PK11195-PET binding in normal-appearing white matter in clinically isolated syndrome

The most accurate predictor of the subsequent development of multiple sclerosis in clinically isolated syndrome is the presence of lesions at magnetic resonance imaging. We used in vivo positron emission tomography with (11)C-(R)-PK11195, a biomarker of activated microglia, to investigate the normal-appearing white matter and grey matter of subjects with clinically isolated syndrome to explore its role in the development of multiple sclerosis. Eighteen clinically isolated syndrome and eight healthy control subjects were recruited. Baseline assessment included: history, neurological examination, expanded disability status scale, magnetic resonance imaging and PK11195-positron emission tomography scans. All assessments except the PK11195-positron emission tomography scan were repeated over 2 years. SUPERPK methodology was used to measure the binding potential relative to the non-specific volume, BPND. We show a global increase of normal-appearing white matter PK11195 BPND in clinically isolated syndrome subjects compared with healthy controls (P = 0.014). Clinically isolated syndrome subjects with T2 magnetic resonance imaging lesions had higher PK11195 BPND in normal-appearing white matter (P = 0.009) and their normal-appearing white matter PK11195 BPND correlated with the Expanded Disability Status Scale (P = 0.007; r = 0.672). At 2 years those who developed dissemination in space or multiple sclerosis, had higher PK11195 BPND in normal-appearing white matter at baseline (P = 0.007 and P = 0.048, respectively). Central grey matter PK11195 BPND was increased in subjects with clinically isolated syndrome compared to healthy controls but no difference was found in cortical grey matter PK11195 BPND. Microglial activation in clinically isolated syndrome normal-appearing white matter is diffusely increased compared with healthy control subjects and is further increased in those who have magnetic resonance imaging lesions. Furthermore microglial activation in clinically isolated syndrome normal-appearing white matter is also higher in those subjects who developed multiple sclerosis at 2 years. Our finding, if replicated in a larger study, could be of prognostic value and aid early treatment decisions in clinically isolated syndrome.

The prognostic utility of MRI in clinically isolated syndrome: a literature review

For patients presenting with clinically isolated syndrome, the treating clinician needs to advise the patient on the probability of conversion to clinically definite multiple sclerosis. MR imaging may give useful prognostic information, and there is large body of literature pertaining to the use of MR imaging in assessing patients presenting with clinically isolated syndrome. This literature review evaluates the accuracy of MR imaging in predicting which patients with clinically isolated syndrome will go on to develop long-term disease and/or disability. New and emerging MR imaging technologies and their applicability to patients with clinically isolated syndrome are also considered.

Isolation and identification of myo-inositol crystals from dragon fruit (Hylocereus polyrhizus)

Crystals isolated from Hylocereus polyrhizus were analyzed using four different approaches—X-ray Crystallography, High Performance Liquid Chromatography (HPLC), Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) and Nuclear Magnetic Resonance (NMR) and identified as myo-inositol. The X-ray crystallography analysis showed that the unit-cell parameters were: a = 6.6226 (3) Å, b = 12.0462 (5) Å, c = 18.8942 (8) Å, α = 90.00, β = 93.98, δ = 90.00. The purity of the crystals were checked using HPLC, whereupon a clean single peak was obtained at 4.8 min with a peak area of 41232 μV*s. The LC-MS/MS technique, which is highly sensitive and selective, was used to provide a comparison of the isolated crystals with a myo-inositol standard where the results gave an identical match for both precursor and product ions. NMR was employed to confirm the molecular structure and conformation of the crystals, and the results were in agreement with the earlier results in this study. The discovery of myo-inositol crystals in substantial amount in H. polyrhizus has thus far not been reported and this is an important finding which will increase the marketability and importance of H. polyrhizus as a crop with a wide array of health properties.

Ingested Type I Interferon-State of the Art as Treatment for Autoimmunity Part 2

We have proposed a unifying hypothesis of the etiopathogenesis of autoimmunity that defines autoimmunity as a type I interferon (IFN) immunodeficiency syndrome. We have examined toxicity and potential efficacy in two phase I (type 1 diabetes [T1D], multiple sclerosis [MS]) and phase II clinical trials in T1D and MS. In a phase I open label trial in T1D, ingested IFN-alpha preserved residual beta-cell function in recent onset patients. In a second phase I trial in MS, there was a significant decrease in peripheral blood mononuclear cell IL-2 and IFN-gamma production after ingesting IFN-alpha. In a phase II randomized, placebo-controlled, double-blind trial in MS, 10,000 IU ingested IFN-alpha significantly decreased gadolinium enhancements compared to the placebo group at month 5. TNF-alpha and IFN-gamma cytokine secretion in the 10,000 IU group at month 5 showed a significant decrease that corresponded with the effect of ingested IFN-alpha on decreasing gadolinium enhancements. In a phase II randomized, placebo-controlled, double-blind trial in T1D, patients in the 5,000 unit hrIFN-alpha treatment group maintained more beta-cell function one year after study enrollment compared to individuals in the placebo group. Ingested IFN-alpha was not toxic in these clinical trials. These studies suggest that ingested IFN-alpha may have a potential role in the treatment of autoimmunity.

1H-MRS for the diagnosis of acute disseminated encephalomyelitis: insight into the acute-disease stage

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) is a demyelinating disorder of the central nervous system (CNS). Differentiating ADEM from other inflammatory disorders, such as multiple sclerosis, is not always conclusive using conventional MRI.

OBJECTIVE

To evaluate longitudinal magnetic resonance spectroscopy (MRS) changes that distinguish ADEM from other inflammatory disorders.

MATERIALS AND METHODS

MRI/MRS scans were performed in seven patients with ADEM during the acute and chronic phases of the disease.

RESULTS

Partial recovery was detected between the acute and chronic phases in choline/creatine ratio. Major elevation of lipids and reduction in myo-inositol/creatine ratio was detected in all patients during the acute phase, followed by a reduction in lipids peak and elevation above normal in myo-inositol/creatine ratio during the chronic phase.

CONCLUSION

Consistent and unique MRS changes in metabolite ratios between the acute and chronic presentations of the disease were found. To the best of our knowledge, these patterns have not been described in other inflammatory disorders and might assist in the early diagnosis of ADEM.

Cellular consequences of inositol depletion

The inositol-depletion hypothesis was suggested to explain the therapeutic mechanism of mood-stabilizing drugs. Focus was previously on the phosphatidylinositol signalling pathway and on the regulatory roles of Ins(3,4,5)P3 and DAG (diacylglycerol). Recent findings indicate that inositol and inositol-containing molecules, including phosphoinositides and inositol phosphates, have signalling and regulatory roles in many cellular processes. This suggests that depleting inositol may lead to perturbation of a wide range of cellular functions, at least some of which may be associated with bipolar disorder.

Cerebrospinal fluid biomarkers in multiple sclerosis

In patients with multiple sclerosis (MS) intensive efforts are directed at identifying biomarkers in bodily fluids related to underlying disease mechanisms, disease activity and progression, and therapeutic response. Besides MR imaging parameters cerebrospinal fluid (CSF) biomarkers provide important and specific information since changes in the CSF composition may reflect disease mechanisms inherent to MS. The different cellular and protein-analytical methods of the CSF and the recommended standard of the diagnostic CSF profile in MS are described. A brief update on possible CSF biomarkers that might reflect key pathological processes of MS such as inflammation, demyelination, neuroaxonal loss, gliosis and regeneration is provided.

The effects of interferon beta-1a on proton MR spectroscopic imaging in patients with multiple sclerosis, a controlled study, preliminary results

To evaluate the effects of interferon beta-1a(INFbeta-1a) on brain metabolites in patients with multiple sclerosis (MS), we performed Magnetic Resonance Spectroscopy Imaging (MRSI) on five patients treated with INFbeta-1a (Rebif 44 microg), and on five untreated patients. Six healthy volunteers were used as controls. Patients were evaluated at the beginning, in the first, third, sixth, and twelfth month. There were no significant differences in normal appearing white matter (NAWM) metabolite peaks of the control group and patients with MS. However, in white matter lesions (WML) and NAWM there was significant differences between the basal and the other months' metabolic peaks (p < 0.05) in the treatment group although no differences emerged in the untreated group. These data suggest that INFbeta-1a has a favorable effect on restoration of metabolites in MS lesions.

Pathological laughing as a manifestation in a clinically isolated brainstem syndrome: a case report

The prevalence of pathological laughing and crying in multiple sclerosis (MS) is 10%. It has been speculated that the anatomical lesion responsible for the pathological laughing is located in the pontine base, prefrontal cortex, and cerebellum. We report an 18-year-old male patient presenting with pathological laughing and hypomania. In his neurological examination, he had a euphoric effect with ataxic walking and dysarthria speech. He had a bilateral conjugated gaze limitation, with a prominent bilateral horizontal nystagmus on left gaze, dysmetria, dysdiadokokinesia, and remarkable dysfunction in a heel-to-shin test on the left. The IgG index in cerebrospinal fluid was normal with an oligoclonal band was present. In cranial MRI, there was a lesion on central pons which was hypointense in T1 images with contrast enhancement and hyperintense in T2 and flair images. Also another lesion in right brachium pontis which did not contrast enhancement but was hyperintense on T2 and flair images was present. There was an elevation of myoinositol/creatine ratio and choline and a reduction of NAA in proton MR spectroscopy. MR spectroscopic evaluation of the patient demonstrated the demyelination process. There has been no report of patients in whom pathological laughter was the presenting symptom of clinically isolated brainstem syndrome.

Cerebrospinal fluid biomarkers of neurodegeneration in chronic neurological diseases

Chronic neurological diseases (CND) like amyotrophic lateral sclerosis (ALS), dementia or multiple sclerosis (MS) share a chronic progressive course of disease that frequently leads to the common pathological pathway of neurodegeneration, including neuroaxonal damage, apoptosis and gliosis. There is an ongoing search for biomarkers that could support early diagnosis of CND and help to identify responders to interventions in therapeutic treatment trials. Cerebrospinal fluid (CSF) is a promising source of biomarkers in CND, since the CSF compartment is in close anatomical contact with the brain interstitial fluid, where biochemical changes related to CND are reflected. We review recent advances in CSF biomarkers research in CND and thereby focus on markers associated with neurodegeneration.

Axonal damage but no increased glial cell activity in the normal-appearing white matter of patients with clinically isolated syndromes suggestive of multiple sclerosis using high-field magnetic resonance spectroscopy

BACKGROUND AND PURPOSE

Proton MR spectroscopy ((1)H-MR spectroscopy) is a well-established method for the in vivo investigation of the normal-appearing white matter (NAWM) in patients with multiple sclerosis (MS). Metabolic changes in NAWM are of special interest in patients with clinically isolated syndromes (CIS) suggestive of MS regarding further prognostic classifications. The purpose of this study was to investigate metabolic alterations in NAWM in patients with CIS with use of high-field (1)H-MR spectroscopy and to compare the results to those in patients with an early course of MS.

MATERIALS AND METHODS

With use of a 3T whole-body MR imaging system, single-voxel (1)H-MR spectroscopy (PRESS; TR: 2000 ms; TE: 38 ms and 140 ms) of the parietal NAWM was performed in 20 control subjects, 36 patients with CIS, and 12 patients with MS. Metabolite ratios and concentrations of N-acetylaspartate (tNAA), myo-inositol (mIns), choline, and total creatine (tCr) were determined.

RESULTS

Compared with the control group, mean NAWM mIns concentrations were significantly elevated in the MS group (4.56 mmol/L versus 3.75 mmol/L, P = .02) but not in the CIS group (4.04 mmol/L, P = .44). The higher concentration of mIns in the MS group was also reflected in the increased Ins/tCr ratio (P = .02). The mean NAWM tNAA was significantly decreased in both patient groups compared with the control group (CIS, 13.42 mmol/L, P = .02; MS, 12.77 mmol/L versus 14.51 mmol/L, P = .008).

CONCLUSIONS

A significant increase of the activity of the glial cells can only be observed in patients with an established diagnosis of MS but not in patients with CIS. Axonal damage occurs already during the first demyelinating episode in patients with CIS as well as in patients with definite MS.

Relationships between gray matter metabolic abnormalities and white matter inflammation in patients at the very early stage of MS : a MRSI study

Proton magnetic resonance spectroscopic imaging ((1)H-MRSI) was used to study metabolic abnormalities inside the gray matter (GM) during or distant to white matter (WM) inflammatory processes reflected by T(1) gadolinium-enhancing lesions in patients at the very early stage of multiple sclerosis (MS). The spectroscopic examination was performed in the axial plane using a home-designed acquisition-weighted, hamming shape, 2D-SE pulse sequence (TE = 135 ms; TR = 1,600 ms). Bilateral thalami and the medial occipital cortex were explored in 35 patients (15 with and 20 without T(1)-Gd enhancing lesions) with clinically isolated syndrome suggestive of MS and in 30 controls. The mean duration since the first presenting symptom was 9.1 (+/-6.7) months. The two groups of patients (with or without T(1) Gd-enhancing lesions) did not differ in terms of time elapsed since the first clinical onset and T(2) lesion load. The spatial contamination of surrounding WM tissues was obtained in each GM region by determining the tissue component in the ROI from GM and WM probability maps smoothed with the point spread function of the MRSI acquisition. Contribution of WM signal was important (60%) inside thalami while the region centered on the medial occipital cortex was well representative of GM metabolism (>70%). Comparisons of relative metabolite levels (ratios of each metabolite over the sum of all metabolites) between all patients and controls showed significant decrease in relative N-acetyl aspartate (NAA) levels, increase in relative choline-containing compounds (Cho) levels and no change in relative creatine/phosphocreatine levels inside the three ROIs. Decrease in relative NAA levels and increase in relative Cho levels were found in patients with inflammatory activity, while no metabolic alterations were present in patients without T(1) Gd-enhancing lesions. These results suggest that abnormalities in GM metabolism observed in patients at the very early stage of MS are mainly related to neuronal dysfunction occurring during acute inflammatory processes.

A brain magnetization transfer MRI study with a clinical follow up of about four years in patients with clinically isolated syndromes suggestive of multiple sclerosis

Whereas it is important to gain prognostic information in patients with clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS), there is still a lack of definitive data about the significance of normal-appearing white (NAWM) and gray (NAGM) matter damage in these patients. The aim of this study was to clarify the role of magnetization transfer magnetic resonance imaging (MT MRI) in assessing "occult" damage at the earliest clinical stage of MS. Dual echo, post-contrast T1-weighted, and MT MRI were obtained from 43 CIS patients with paraclinical evidence of spatial disease dissemination within 3 months from disease onset and from 22 controls. In patients, conventional MRI was obtained after 3 and 12 months from the baseline assessment, to detect disease dissemination in time (DIT). A neurological examination was also conducted to ascertain the occurrence of relapses for an average follow up period of 1389 (range = 420-1847) days. MTR maps were derived and NAWM and NAGM MT ratio (MTR) histograms were analyzed. During the follow up, 30 patients showed MRI evidence of DIT, and 21 experienced a relapse. T2 lesion volume (LV) was significantly higher in patients with DIT than in those without (p=0.005). MTR histogram variables did not significantly differ between patients with MRI or clinical DIT. T2 LV was the only significant predictor of clinical DIT at follow-up (p=0.001). This study shows that MT MRI-detectable damage to NAWM and NAGM may not be an important feature of all patients at presentation with a CIS highly suggestive of MS and that such a damage may develop with subsequent disease evolution.

Glycogen synthase kinase‐3 is required for optimalde novosynthesis of inositol

Studies have shown that the inositol biosynthetic pathway and the enzyme glycogen synthase kinase-3 (GSK-3) are targets of the mood-stabilizing drugs lithium and valproate. However, a relationship between these targets has not been previously described. We hypothesized that GSK-3 may play a role in inositol synthesis, and that loss of GSK-3 may lead to inositol depletion, thus providing a mechanistic link between the two drug targets. Utilizing a yeast Saccharomyces cerevisiae gsk-3Delta quadruple-null mutant, in which all four genes encoding homologues of mammalian GSK-3 are disrupted, we tested the hypothesis that GSK-3 is required for de novo inositol biosynthesis. The gsk-3Delta mutant exhibited multiple features of inositol depletion, including defective growth in inositol-lacking medium, decreased intracellular inositol, increased INO1 and ITR1 expression, and decreased levels of phosphatidylinositol. Treatment of wild-type cells with a highly specific GSK-3 inhibitor led to a significant increase in INO1 expression. Supplementation with inositol alleviated the temperature sensitivity of gsk-3Delta. Activity of myo-inositol-3 phosphate synthase, the rate-limiting enzyme in inositol de novo biosynthesis, was decreased in gsk-3Delta. These results demonstrate for the first time that GSK-3 is required for optimal myo-inositol-3 phosphate synthase activity and de novo inositol biosynthesis, and that loss of GSK-3 activity causes inositol depletion.

Structural and functional surrogates of cognitive impairment at the very early stage of multiple sclerosis

Following our previous reports based on parametric MRI methods (T(2)-weighted MRI, statistical mapping analysis of magnetization transfer ratio images and functional MRI) applied to a population of 18 patients with clinically isolated syndrome suggestive of multiple sclerosis, we have reviewed the possible structural and functional surrogates of MS that could explain the subtle cognitive impairment related to attention and working memory deficits evaluated with paced auditory serial addition test (PASAT). We propose that the brain substrates underlying cognitive impairment observed at the very early stage of MS are multifactorial. Several components could influence PASAT performances in patients: i) the extent of diffuse white matter damage, ii) the location of visible and non visible lesions, iii) the connectivity efficiency between distant brain functional areas involved in working memory processes and iv) the cortical reorganization. Nevertheless, individually, each of these parameters may have few influences on PASAT performance in patients. Using a multiregression model built with independent MR parameters, a very good evaluation of PASAT scores has been obtained in this limited number of patients explaining 90% of the variance. In conclusion, the different aspects of tissue and functional pathological brain underpinnings must be accounted to monitor accurately new therapeutic strategies for the treatment of early cognitive deficits related to MS.

Can MRI reveal phenotypes of multiple sclerosis?

The multicontrast capability of magnetic resonance imaging (MRI) is discussed in its role in the search for phenotypes of multiple sclerosis (MS). Aspects of MRI specificity, putative markers for pathogenetic components of disease and issues of spatial and temporal distribution are discussed. While particular reference is made to MS, the concepts apply to common pathological features of many neurologic diseases and to neurodegenerative disease in general. The assessment and dissociation of disease activity and disease severity, as well as the combination of varied metrics for the purposes of inferential and predictive disease modeling, are explored with respect to biomarkers and clinical outcomes. By virtue of its noninvasive nature and multicontrast capabilities depicting multiple facets of MS pathology, MRI lends itself to the systematic search of pathogenetically distinct subtypes of MS in large populations of patients. In conjunction with clinical, immunological, serological and genetic information, clusters of MS patients with distinct clinical prognosis and diverse response profiles to available and future treatments may be identified.

Selective magnetization transfer ratio decrease in the visual cortex following optic neuritis

Patients with clinically isolated syndromes suggestive of multiple sclerosis have evidence for abnormality in normal appearing grey matter detected using the magnetization transfer ratio (MTR), a quantitative MRI measure. One potential mechanism for the decreased grey matter MTR (GM MTR) observed is trans-synaptic morphological abnormality secondary to demyelinating lesions that are in an anatomically linked pathway but remote location. We investigated this potential association by studying the location of abnormalities using voxel-based analysis of GM MTR maps in a group of 80 patients studied within 6 months of presenting with isolated optic neuritis and compared the findings with those seen in 50 age- and sex-matched healthy controls. Occipital cortex and whole brain analysis comparing all optic neuritis patients and controls revealed a selective decrease of MTR bilaterally in the visual cortex in patients [Brodmann area (BA) 17]. Whole brain analysis of patients fulfilling the McDonald criteria for multiple sclerosis (n = 20) showed a lower MTR compared to controls bilaterally in the visual cortex (BA 17/18), left hippocampus, bilateral superior temporal gyrus, bilateral lenticular nuclei and the right cerebellum. There was no significant difference in the percentage of grey matter between patients and controls in the regions of abnormal MTR detected in the visual cortex. The intrinsic MTR decrease seen in patients suggests that there are structural changes in the visual cortex following an attack of optic neuritis. Potential mechanisms for this include trans-synaptic neuronal degeneration and cortical synaptic morphological changes; such abnormalities may also contribute to MTR abnormalities observed in the normal appearing grey matter in multiple sclerosis.

1H-MRS quantification of tNA and tCr in patients with multiple sclerosis: a meta-analytic review

Meta-analysis was performed on the results of 75 comparisons from the 30 peer-reviewed publications that used proton magnetic resonance spectroscopy (1H-MRS) or spectroscopic imaging to (i) quantify the mean concentrations of total creatine (tCr, found in neurons, astrocytes and oligodendrocytes), and/or total N-acetyl groups (tNA, found only in neurons), in the lesional and/or non-lesional white matter (WM) and/or the grey matter (GM) of patients with multiple sclerosis (MS) and (ii) compare these values with those in the homologous tissues of normal controls (NC). For mean [tNA] values, there was (i) a large-effect-sized overall decrease in patients' lesional WM relative to NC WM (25 comparisons), (ii) a medium-effect-sized overall decrease in patients' non-lesional WM relative to NC WM (36 comparisons) and (iii) a medium-effect-sized overall decrease in patients' GM relative to NC GM (14 comparisons). Patients' mean [tNA] values were sometimes statistically normal but were never statistically increased. For mean [tCr] values, there was (i) no statistically significant overall change in the patients' lesional WM relative to NC WM (24 comparisons), although statistically significant increases and decreases were sometimes found, (ii) a medium-effect-sized overall increase in patients' non-lesional WM relative to NC WM (33 comparisons) and (iii) no statistically significant overall change in patients' GM relative to NC GM (12 comparisons), although a significant decrease was found in one comparison. Of 41 comparisons with statistically significant changes, 38 combined in a way that would probably result in decreased mean [tNA]/[tCr] ratios such that (i) 66% had statistically decreased mean [tNA] and statistically unchanged mean [tCr] values, (ii) 13% had statistically decreased mean [tNA] and statistically increased mean [tCr] values and (iii) 21% had statistically unchanged mean [tNA] values and statistically increased mean [tCr] values. Of the 25 comparisons that came from studies that also analysed [tNA]/[tCr] ratios, the direction of change in mean [tNA] values and mean [tNA]/[tCr] ratios was concordant in 84%. In comparisons that quantified both [tNA] and [tCr], there was a similar amount of variability in both measures in each of the different tissue types studied, both in patients and NCs. Together, these results suggest that within-voxel tNA/tCr ratios can be interpreted as valid and accurate surrogate measures of 'cerebral tissue integrity'-with decreased tNA/tCr ratios indicating some combination of neuroaxonal disturbance, oligodendroglial disturbance, and astrocytic proliferation. These results also suggest that, although within-voxel tNA/tCr ratios are not perfect indicators of [tNA] content, they do represent a practical compromise to acquiring surrogate measures of within-voxel neuroaxonal integrity.

MRI in multiple sclerosis

MRI provides multiple uses and applications in multiple sclerosis(MS). The basic features of the MRI-detected lesions, including the underlying pathology, are discussed. MRI allows assessment of the normal-appearing white and gray matter, and neuronal tract and functional system disturbances. An overview of the clinical significance of these MRI measures is included, as a basis for understanding their role as outcome measures in clinical trials. MRI recently assumed greater importance in its role in establishing an earlier diagnosis of MS after a first clinical event, and in monitoring subclinical disease before or subsequent to the formal diagnosis. The background to these applications and practical issues are discussed.

Clinically isolated syndromes suggestive of multiple sclerosis, part 2: non-conventional MRI, recovery processes, and management

The onset of multiple sclerosis (MS) in 85% of young adults is with a subacute clinically isolated syndrome (CIS) of the optic nerves, brainstem, or spinal cord. Whereas multifocal brain lesions are present on MRI in many patients with a CIS, some patients have additional abnormalities on quantitative MRI in otherwise normal-appearing white and grey matter that suggest an extensive pathological process. Functional outcome for patients with symptomatic CIS lesions is determined by the interplay of inflammation, demyelination, axonal damage, remyelination, and cortical adaptation. Recovery of function may be accelerated by high dose corticosteroids, and although interferon beta delays the development of a second relapse, its long-term effect is unknown. A better understanding of pathological and pathogenetic processes in patients with a CIS will facilitate the development of disease-modifying treatments for patients with MS before they become disabled. Continued clinical and laboratory investigation of patients with a CIS should be encouraged.

Discrimination of white matter lesions and multiple sclerosis plaques by short echo quantitative 1H—magnetic resonance spectroscopy

Multiple sclerosis (MS) plaques and age related white matter lesions (WML) are of similar morphological appearance on T2 weighted MRI. Therefore their differentiation is sometimes crucial. Proton magnetic resonance spectroscopy ((1)H-MRS) adds metabolic information to conventional imaging and may help to distinguish inflammatory MS plaques from vascular related WML. This study was performed to evaluate the metabolite pattern in MS plaques and WML. 15 MS patients, 14 elderly individuals with WML and 16 controls were investigated by conventional MRI and short echo quantitative (1)H-MRS (TE: 30ms, TR: 3000ms). The mean metabolite concentrations in normal control white matter (NCWM), MS plaques and WML were: t-NAA: 8.96 mmol/l (SD: 0.93) vs 6.79 mmol/l (SD: 1.99) vs 7.18 mmol/l (SD: 1.41); Cho:1.66 mmol/l (SD: 0.4) vs 1.49 mmol/l (SD: 0.45) vs 1.46 mmol/l (SD: 0.34); PCr:5.64 mmol/l (SD: 0.83) vs 4.9mmol/l (SD: 1.3) vs 4.95 mmol/l (SD: 0.86); myo-Ins: 4.57 mmol/l (SD:1.05) vs 6.34 mmol/l (SD: 2.03) vs 4.5 mmol/l (SD: 0.96). t-NAA reduction in MS plaques and WML was significant compared with controls (p <or= 0.001). MS plaques showed significantly elevated myo- Ins concentrations compared with controls (p = 0.002) and to WML (p = 0.003). In summary MS plaques and WML show a decrease in their t-NAA concentrations compared with controls. Elevated concentrations of myo-Ins in MS plaques but not in WML makes this metabolite of special interest for their differentiation.

Magnetic resonance study of the influence of tissue damage and cortical reorganization on PASAT performance at the earliest stage of multiple sclerosis

We sought to determine the influence of tissue damage and the potential impact of cortical reorganization on the performance to the Paced Auditory Serial Addition Test (PASAT) in patients at the earliest stage of multiple sclerosis (MS). Magnetization transfer ratio (MTR) imaging and functional magnetic resonance imaging (fMRI) experiments using PASAT as paradigm were carried out in 18 patients with clinically isolated syndrome suggestive of MS (CISSMS) compared to 18 controls. MTR histogram analyses showed structural abnormalities in patients involving the normal-appearing white matter (NAWM) but also the gray matter (GM). Mean PASAT scores were significantly lower in the group of patients taken as a whole, and were correlated with the mean NAWM MTR value. No correlation was observed between PASAT scores and GM MTR. However, in the subgroup of patients with normal PASAT performance (n = 9), fMRI showed larger activations in bilateral Brodmann area 45 (BA45) and right BA44 compared to that in controls (n = 18). In these areas with potentially compensatory reorganization, the whole group of patients (n = 18) showed significantly greater activation than controls (n = 18). Activation in the right BA45 was inversely correlated with the mean NAWM MTR and the peak position of GM MTR histograms of patients. This study indicates that even at the earliest stage of MS, cortical reorganization is present inside the executive system of working memory and could tend to limit the determinant functional impact of NAWM injury on the execution of the PASAT.

Imaging of multiple sclerosis: role in neurotherapeutics

Magnetic resonance imaging (MRI) plays an ever-expanding role in the evaluation of multiple sclerosis (MS). This includes its sensitivity for the diagnosis of the disease and its role in identifying patients at high risk for conversion to MS after a first presentation with selected clinically isolated syndromes. In addition, MRI is a key tool in providing primary therapeutic outcome measures for phase I/II trials and secondary outcome measures in phase III trials. The utility of MRI stems from its sensitivity to longitudinal changes including those in overt lesions and, with advanced MRI techniques, in areas affected by diffuse occult disease (the so-called normal-appearing brain tissue). However, all current MRI methodology suffers from limited specificity for the underlying histopathology. Conventional MRI techniques, including lesion detection and measurement of atrophy from T1- or T2-weighted images, have been the mainstay for monitoring disease activity in clinical trials, in which the use of gadolinium with T1-weighted images adds additional sensitivity and specificity for areas of acute inflammation. Advanced imaging methods including magnetization transfer, fluid attenuated inversion recovery, diffusion, magnetic resonance spectroscopy, functional MRI, and nuclear imaging techniques have added to our understanding of the pathogenesis of MS and may provide methods to monitor therapies more sensitively in the future. However, these advanced methods are limited by their cost, availability, complexity, and lack of validation. In this article, we review the role of conventional and advanced imaging techniques with an emphasis on neurotherapeutics.

Multi-slice echo-planar spectroscopic MR imaging provides both global and local metabolite measures in multiple sclerosis

MR spectroscopy (MRS) provides information about neuronal loss or dysfunction by measuring decreases in N-acetyl aspartate (NAA), a metabolite widely believed to be a marker of neuronal viability. In multiple sclerosis (MS), whole-brain NAA (WBNAA) has been suggested as a marker of disease progression and treatment efficacy in treatment trials, and the ability to measure NAA loss in specific brain regions early in the evolution of this disease may have prognostic value. Most spectroscopic studies to date have been limited to single voxels or nonlocalized measurements of WBNAA only, and longitudinal studies have often been hampered by standardization and reproducibility problems. Multi-slice echo-planar spectroscopic imaging (EPSI) is presented as a promising alternative to single-voxel or nonlocalized spectroscopy for obtaining global metabolite estimates in MS. In the same session, measurements of metabolites in specific brain areas chosen after image acquisition (e.g., normal-appearing white matter (NAWM), gray matter (GM), and lesions) can be obtained. The identification and exclusion of regions that are inadequate for spectroscopic evaluation in global assessments can significantly improve quality and reproducibility, as demonstrated by a low within-subject variance in healthy controls. The reproducibility of the technique makes it a promising tool for future longitudinal spectroscopic studies of MS.

Mechanisms of axon-glial injury of the optic nerve

The central concept underlying ideas on the pathogenesis of multiple sclerosis is that inflammatory events cause acute injury of axons and myclin. The phases of symptom onset, recovery, persistence, and progression in multiple sclerosis can be summarized as functional impairment with intact structure due to direct effects of inflammatory mediators; demyelination and axonal injury with recovery through plasticity and remyelination; and chronic axonal loss due to failure of enduring remyelination from loss of trophic support for axons normally provided by cells of the oligodendrocyte lineage. Cell death may occur in response to a state of injury from which protection would be anticipated under more favourable neurobiological conditions. Conversely, optimal growth factor environment may save cells from otherwise lethal events occurring at the cell membrane. Hence, in the context of brain inflammation, there is an inseparable interplay between immunological and neurobiological contributions to tissue injury.

Effectiveness of interferon beta treatment in relapsing-remitting multiple sclerosis: an Italian cohort study

RATIONALE, AIMS AND OBJECTIVES

Randomized clinical trials (RCTs) have provided evidence for the efficacy of interferon beta (IFNbeta) in the treatment of relapsing-remitting multiple sclerosis (RRMS). The aim of this study was to evaluate the effectiveness of IFNbeta treatment in clinical practice.

METHODS

This was a national, multicentre, observational study of patients with confirmed RRMS. Demographic, clinical and therapeutic data were retrospectively collected for each patient enrolled in the study.

RESULTS

The study cohort consisted of 427 patients exposed to and 245 never exposed to IFNbeta treatment during the study period (for a total 2297 patient-years of follow-up). Among the exposed patients, 215 were initially untreated and then began IFNbeta later in the follow-up period; 137 of these patients were exposed to IFNbeta for more than 2 years. In these patients, IFNbeta treatment reduced the mean relapse rate by 24.2%[95% confidence interval (CI): 5.8-42.5%]. For 640 of the 672 patients enrolled in the study, it was possible to calculate the area under the disability/time curve compared to that present at baseline. A total of 117 (18.3%) patients displayed disability progression. Adjustment of the disability progression rates for potential confounders and/or for propensity scores by Poisson regression model resulted in relative risks for patients exposed to IFNbeta treatment compared to those never exposed to IFNbeta of 0.87 (95% CI: 0.56-1.34) after an exposure of < or = 2 years, and of 0.35 (95% CI: 0.21-0.60) after an exposure of >2 years.

CONCLUSIONS

These findings suggest that the evidence from RCTs on the treatment of RRMS with IFNbeta has been effectively translated into routine clinical practice.

cDNA cloning and gene expression analysis of human myo-inositol 1-phosphate synthase

myo-Inositol 1-phosphate synthase (EC 5.5.1.4) (IPS) is a key enzyme in myo-inositol biosynthesis pathway. This study describes the molecular cloning of the full length human myo-inositol 1-phosphate synthase (hIPS) cDNA, tissue distribution of its mRNA and characterizes its gene expression in cultured HepG2 cells. Human testis, ovary, heart, placenta, and pancreas express relatively high level of hIPS mRNA, while blood leukocyte, thymus, skeletal muscle, and colon express low or marginal amount of the mRNA. In the presence of glucose, hIPS mRNA level increases 2- to 4-fold in HepG2 cells. hIPS mRNA is also up-regulated 2- to 3-fold by 2.5 microM lovastain. This up-regulation is prevented by mevalonic acid, farnesol, and geranylgeraniol, suggesting a G-protein mediated signal transduction mechanism in the regulation of hIPS gene expression. hIPS mRNA expression is 50% suppressed by 10mM lithium ion in these cells. Neither 5mM myo-inositol nor the three hormones: estrogen, thyroid hormone, and insulin altered hIPS mRNA expression in these cells.

The use of quantitative magnetic-resonance-based techniques to monitor the evolution of multiple sclerosis

Conventional MRI can improve accuracy in the diagnosis of multiple sclerosis (MS) and monitor the efficacy of experimental treatments. However, conventional MRI provides only gross estimates of the extent and nature of tissue damage associated with this disease. Other quantitative magnetic-resonance-based techniques have the potential to overcome the limitations of conventional MRI and, as a consequence, to improve our understanding of the natural history of MS. Magnetisation-transfer, diffusion-weighted, and functional MRI--as well as proton magnetic-resonance spectroscopy--are helping us to elucidate the mechanisms that underlie injury, repair, and functional adaptation in patients with MS. These techniques are substantially changing our understanding of how MS causes irreversible disability and should be used more extensively in clinical trials and in studies of disease progression.

Evidence for axonal pathology and adaptive cortical reorganization in patients at presentation with clinically isolated syndromes suggestive of multiple sclerosis

Previous work has suggested that functional reorganization of cortical areas might have a role in limiting the clinical impact of axonal pathology in patients with established multiple sclerosis (MS). Since there is evidence for irreversible tissue damage even in patients with early MS, we assessed, using functional MRI (fMRI) and a general search method, the brain pattern of movement-associated cortical activations in patients at presentation with clinically isolated syndromes (CIS) suggestive of MS. To elucidate the role of cortical reorganization in these patients, we also investigated the extent to which the fMRI changes correlated with the extent of overall axonal injury of the brain. From 16 right-handed patients at presentation with CIS and 15 right-handed, age- and sex-matched healthy volunteers, we obtained: (1). fMRI (repetitive flexion-extension of the last four fingers of the right hand), (2). conventional MRI scans, and (3). a new, unlocalized proton MR spectroscopy ((1)HMRS) sequence to measure the concentration of N-acetylaspartate of the whole brain (WBNAA). Compared to controls, patients with CIS had more significant activations of the contralateral primary somatomotor cortex (SMC), secondary somatosensory cortex, and inferior frontal gyrus. They also had significant decreased WBNAA concentration. Relative activation of the contralateral primary SMC was strongly correlated with WBNAA levels (r = -0.78, P < 0.001). This study shows that axonal pathology and functional cortical changes over a rather distributed sensorimotor network occur in patients at presentation with CIS suggestive of MS and that these two aspects of the disease are strictly correlated. This suggests that the increased functional recruitment of the cortex in these patients might have an adaptive role in limiting the clinical impact of irreversible tissue damage.

Progressive ventricular enlargement in patients with clinically isolated syndromes is associated with the early development of multiple sclerosis

BACKGROUND

In patients with clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS), the extent of brain magnetic resonance imaging (MRI) lesion load influences the probability and time to development of clinically definite MS. Cerebral atrophy is recognised in established MS, but its time of onset and whether, in early disease, it is related to MRI lesion load or clinical outcome is less certain.

OBJECTIVES

This study investigated ventricular enlargement over one year in CIS patients and explored its relation with lesion load and clinical outcome.

METHODS

A semi-automated thresholding technique for measuring ventricular volume (MIDAS) was applied to MRI scans in a cohort of 55 patients with CIS, recruited consecutively and imaged within three months of the onset of symptoms and again after one year.

RESULTS

Clinical MS had developed after one year in 16 of 40 patients with an abnormal baseline T2 scan and 2 of 15 with a normal scan. Significant ventricular enlargement was seen in 27 of 55 patients who fulfilled the new McDonald MRI criteria for MS using all available MRI at clinical follow up (median increase 0.3 cm(3), p=0.005) Significant increase in ventricular volume was also seen in the 18 of 55 patients who developed clinical MS over the follow up period (median increase 0.5 cm(3), p=0.006). There were significant but modest correlations between baseline lesion measures and subsequent ventricular enlargement.

CONCLUSIONS

(1) Lesions and atrophy are both associated with early relapse leading to a diagnosis of clinical MS; (2) while lesions contribute to the development of atrophy, atrophy may also develop by other mechanisms. This suggests that MR measures have a complementary role in monitoring the course of MS, even from the earliest clinical stage.

Application of the new McDonald criteria to patients with clinically isolated syndromes suggestive of multiple sclerosis

Traditionally, multiple sclerosis (MS) has been diagnosed on the basis of clinical evidence of dissemination in time and space. Previously, it could not be diagnosed in patients with single clinical episodes of demyelination known as clinically isolated syndromes. New diagnostic criteria from the International Panel of McDonald and colleagues incorporate MRI evidence of dissemination in time and space to allow a diagnosis of MS in patients with clinically isolated syndromes. From clinical and MRI examinations performed prospectively at baseline, 3 months, 1 year, and 3 years of follow-up, the frequency of developing MS was ascertained by the application of both the new McDonald criteria and the Poser criteria for clinically definite MS. The specificity, sensitivity, positive and negative predictive value, and accuracy of the new criteria for the development of clinically definite MS were assessed. At 3 months, 20 of 95 (21%) patients had MS with the McDonald criteria, whereas only 7 of 95 (7%) had developed clinically definite MS. After 1 year, the corresponding figures were 38 of 79 (48%) and 16 of 79 (20%), and after 3 years, they were 29 of 50 (58%) and 19 of 50 (38%). The development of MS with the new MRI criteria after 1 year had a high sensitivity (83%), specificity (83%), positive predicative value (75%), negative predictive value (89%), and accuracy (83%) for clinically definite MS at 3 years. Use of the new McDonald criteria more than doubled the rate of diagnosis of MS within a year of presentation with a clinically isolated syndrome. The high specificity, positive predictive value, and accuracy of the new criteria for clinically definite MS support their clinical relevance.

A longitudinal study of MR diffusion changes in normal appearing white matter of patients with early multiple sclerosis

BACKGROUND AND PURPOSE

The stage at which normal appearing white matter (NAWM) abnormalities first appear in multiple sclerosis (MS) is not clear. The aim of our study was to monitor water diffusion changes over time in NAWM of patients with early MS.

METHODS

Out of a consecutive series of patients enrolled in a MR study on clinically isolated syndrome (CIS), we selected 19 subjects who had completed a one year follow-up. The MR scans obtained at baseline and at 12 months were reviewed according to the new criteria on the diagnosis of MS. Lesion load on T2 and T1 weighted images and the trace of the apparent diffusion coefficient in NAWM were measured both at baseline and at 12 months in patients and in 12 healthy controls.

RESULTS

In three patients the diagnosis of MS was done at baseline based on MR. Thirteen patients developed MS during the study and in three patients the diagnosis remained "possible MS." TADC in NAWM in patients was significantly higher than in controls at the 12 months' follow-up but not at baseline (controls mean tADC +/- sd = 0.745 +/- 0.02 mm(2)/sec x 10(-3); patients mean tADC(12) +/- sd = 0.767 +/- 0.02 mm(2)/sec x 10(-3); p < 0.02). TADC and T2 lesion load at 12 months were significantly correlated (p < 0.01). Patients exhibiting tADC(12) above a confidence interval had a significantly greater EDSS score at the same time period (EDSS(12) +/- sd = 1.9 +/- 0.5 and = 1.1 +/- 0.4 respectively; p < 0.01).

CONCLUSIONS

This study suggests that diffusion MR cannot detect alterations in NAWM of patients with a CIS suggestive of MS. After one year, when most patients develop MS, diffusion MR abnormalities in NAWM become apparent. These abnormalities are correlated with T2 lesion load and may contribute to neurological impairment.

Magnetic resonance spectroscopy in multiple sclerosis: window into the diseased brain

Magnetic resonance spectroscopy provides noninvasive insight into the regional and global biochemical alterations that are concomitants of the dynamic processes that underlie the evolution of fundamental pathologic changes in multiple sclerosis. These include now well-recognized alterations of neuronal biochemical markers that accompany tissue destruction readily visualized by magnetic resonance imaging, but also dynamic changes in several metabolites that indicate pathological processes that precede the magnetic resonance imaging-defined lesion, or completely escape current high-resolution imaging.

Quantitative 1H MRS imaging 14 years after presenting with a clinically isolated syndrome suggestive of multiple sclerosis

clinically isolated syndromes (CIS) are events suggestive for emerging multiple sclerosis (MS). A majority of patients develop MS within months or years whilst others remain clinically isolated. The goal of this study was to investigate whether biochemical metabolites detectable by 'H magnetic resonance spectroscopy (MRS) may serve to distinguish between these two groups. We investigated 41 patients 14 years after presentation with a CIS and 21 controls with combined quantitative short echo 'H MRS and magnetic resonance imaging (MRI) and assessed disability according to the Expanded Disability Status Scale (EDSS). At follow-up, 32 had developed MS, and 9 still had CIS. Compared with controls, MS patients demonstrated significantly higher concentrations of myo-inositol (Ins) in normal appearing white matter (NAWM) and lesions. Lesions also demonstrated a reduced N-acetyl-aspartate (NAA) level and an increase in choline-containing compounds (Cho). The NAWM Ins concentration was correlated with EDSS (r = 0.48, p = 0.005). MS normal appearing cortical grey matter (CGM) exhibited a decreased NAA. Patients who remained CIS did not differ significantly from controls in any MRS measure. Metabolite changes in normal appearing white and grey matter in MS indicate diffuse involvement of the entire MS brain, which was not seen in the persisting CIS patients. Elevated Ins in MS NAWM appeared functionally relevant It may indicate glial cell proliferation or gliosis.

Multiple sclerosis

Multiple sclerosis is the prototype inflammatory autoimmune disorder of the central nervous system and, with a lifetime risk of one in 400, potentially the most common cause of neurological disability in young adults. As with all complex traits, the disorder results from an interplay between as yet unidentified environmental factors and susceptibility genes. Together, these factors trigger a cascade of events, involving engagement of the immune system, acute inflammatory injury of axons and glia, recovery of function and structural repair, post-inflammatory gliosis, and neurodegeneration. The sequential involvement of these processes underlies the clinical course characterised by episodes with recovery, episodes leaving persistent deficits, and secondary progression. The aim of treatment is to reduce the frequency, and limit the lasting effects, of relapses, relieve symptoms, prevent disability arising from disease progression, and promote tissue repair. Despite limited success in each of these categories, everyone touched by multiple sclerosis looks for a better dividend from applying an improved understanding of the pathogenesis to clinical management.

A longitudinal study of brain atrophy and cognitive disturbances in the early phase of relapsing-remitting multiple sclerosis

OBJECTIVE

(a) To establish whether the cognitive decline of the early phase of relapsing-remitting multiple sclerosis depends on the progression of the burden of disease, or on the loss of brain parenchyma, or is influenced by both; (b) to monitor the loss of brain parenchyma in the early phase of the disease; and (c) to examine its possible relation with the progression of physical disability.

METHODS

For 2 years 53 patients with clinically definite relapsing-remitting multiple sclerosis with disease duration 1-5 years and expanded disability status scale < or =5.0 at baseline were monitored. The neuropsychological performances, the psychological functioning, the neurological impairment, and the disability have been assessed at baseline and after 2 years. Patients also underwent PD/T2 and T1 weighted brain MRI. T2 and T1 lesion volumes were measured by a semiautomatic technique. Quantification of brain parenchymal volumes was obtained using a highly reproducible computerised interactive program. The relation between cognitive impairment and MRI findings has been investigated by partial correlation and stepwise multiple regression analyses excluding the effects of age, education, anxiety, depression, and total days of steroid use.

RESULTS

In the 2 years of the study the mean change for T2 and T1 lesion volumes and brain parenchymal volumes were +1.7 ml (95% confidence interval (95% CI) 1.3-2.2, p=0.005, (29.8%); +0.2 ml, 95% CI 0.15-0.26, p=0.004, (25%); and -32.3 ml, 95% CI 24.2-42.3, p<0.0001, (2.7%), respectively. Overall, 14 patients (26.4%) were judged to be cognitively impaired at baseline and 28 (52.8%) at the end of the follow up. Of the 18 neuropsychological tests and subtests employed in the study, patients with multiple sclerosis failed 5.8 (SD 2.3) tests at the baseline and 8.4 (SD 2.9) (p<0.0001) tests at the end of the study. When the cognitive changes were examined in individual patients, five (9.4%) of them were considered cognitively improved, 33 (62.3%) remained stable, and 15 (28.3%) worsened over 2 years. T2 and T1 volume changes in improved, stable, and worsened patients did not show any significant difference, whereas brain parenchymal volume decrease in cognitively worsened patients was significantly greater (-66 ml (5.4%), 95% CI 37-108.9, p=0.0031). The cognitive impairment was independently predicted over 2 years only by the change of brain parenchymal volumes (R=0.51, p=0.0003). Ten patients (18.9%), who worsened by one or more points in the EDSS during the follow up period had significant decreases in brain parenchymal volumes (-99 ml (8%), 95% CI 47.6-182.3, p=0.005). At the end of the study the loss of brain parenchyma correlated significantly with change in EDSS (r= 0.59, p<0.0001).

CONCLUSIONS

In the early phase of relapsing-remitting multiple sclerosis the cognitive deterioration relies more on the development of brain parenchymal volume atrophy than on the extent of burden of disease in the brain. The loss of brain parenchymal volume underlies the progressive accumulation of physical disability from the initial phase of the disease, which becomes more demonstrable only if studied with longer observation periods. Probably, the main pathological substrate of brain atrophy in the early stage of the disease is early axonal loss, which causes the progression of neurological deficits and the development of cognitive impairment. These data support the debated opinion that disease modifying therapy should be initiated as early as possible.

Automatic quantitation of localized in vivo 1H spectra with LCModel

The LCModel method analyzes an in vivo spectrum as a Linear Combination of Model in vitro spectra from individual metabolite solutions. Complete model spectra, rather than individual resonances, are used in order to incorporate maximum prior information into the analysis. A nearly model-free constrained regularization method automatically accounts for the baseline and lineshape in vivo without imposing a restrictive parameterized form on them. LCModel is automatic (non-interactive) with no subjective input. Approximately maximum-likelihood estimates of the metabolite concentrations and their uncertainties (Cramér-Rao lower bounds) are obtained. LCModel analyses of spectra from users with fields from 1.5 to 9.4 T and a wide range of sequences, particularly with short TE, are used here to illustrate the capabilities and limitations of LCModel and proton MRS.

The role of non-conventional MR techniques to study multiple sclerosis patients

Conventional magnetic resonance imaging (MRI) lacks pathological specificity to the heterogeneous substrates of multiple sclerosis (MS) lesions and is not able to detect subtle, disease-related changes in the normal-appearing white matter (NAWM). As a consequence, the correlation between MRI findings and the long-term evolution of MS is moderate at best. To overcome the limitations of conventional MRI, new quantitative magnetic resonance (MR) techniques, such as cell-specific imaging, magnetization transfer imaging (MTI), proton magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI) and functional MR imaging (fMRI) have all been recently applied to the study of MS. These techniques should provide more accurate and pathologically specific estimates of the MS lesion burden than conventional MR and should improve our understanding of the mechanisms leading to MS-related irreversible disability.