Measures in the first year of therapy predict the response to interferon beta in MS

BACKGROUND AND OBJECTIVE

Several criteria for treatment response to interferon beta (IFNbeta) have been proposed, although there is no consensus among different investigators. Hence, the aim of this study was to investigate magnetic resonance imaging (MRI) and clinical predictors of response during the first 12 months of therapy.

METHODS

This is a prospective and longitudinal study of relapsing-remitting multiple sclerosis (RRMS) patients treated with IFNbeta. Patients were classified based on the presence of new lesions on MRI, relapses, confirmed disability increase, or combinations of all these variables after 1 year of therapy. Regression analysis was performed in order to identify variables of response after a follow-up of 3 years.

RESULTS

We included 222 RRMS patients. The logistic model demonstrated that only the combination of new active lesions on MRI with the presence of relapses (OR 4.4; 95% CI 1.6-12.5) or disability progression (Odds Ratio (OR) 7.1; 95% Confidence Interval (CI) 1.6-33.9), or both (OR 6.5; 95% CI 1.9-23.4) achieved significant values to identify those patients with a poor outcome.

CONCLUSIONS

In RRMS patients treated with IFNbeta, the combination of measures of disease activity and the presence of new active lesions on MRI may have a prognostic value for identifying patients with disease activity in the second and third year of therapy.

MET in small cell lung carcinoma (SCLC): Effects of a MET inhibitor in SCLC cell lines and prognostic role of MET status in patients

e14617

Purpose: HGF/MET pathway is aberrantly activated by receptor overexpression and mutations in SCLC preclinical models, enhancing their oncogenicity. The significance of MET expression in SCLC remains unclear. Our aim was to analyze the effects of MET inhibition in chemosensitive/refractory SCLC models and to study the expression pattern and prognostic impact of total and phosphorylated (p) MET in SCLC patients. Methods: Total and p-MET expression (Western Blot), gene copy number (FISH), and exon 14 activating mutations (sequencing) were evaluated in H69 and H69AR SCLC cell lines. PHA-665752 (PHA), alone or combined with doxorubicin, was used to study the effects of pathway inhibition on viability, colony formation and invasion assays in basal/stimulated conditions (HGF). Fifty-eight SCLC cases were evaluated for MET and p-MET expression by immunohistochemistry. Survival analyses were performed. Results: H69 and H69AR (both R988C mutated) expressed MET at basal conditions, but not p-MET. HGF induced MET phosphorylation, increased proliferation (20%) and protected cells from doxorubicin cytotoxicity. PHA 0.5μM blocked MET phosphorylation, decreased colony formation by 50% in H69, counteracted the cytoprotective effect of HGF and inhibited invasion in H69AR. MET expression was found in 98% normal bronchial epithelia, and 78% tumor samples (overexpression 38%). Activated MET was focally detected in normal and metaplastic mucosa and expressed in 22% tumors. MET expression was associated with improved overall and disease free survival (p: 0.06 and 0.051, respectively). All p-MET positive cases within MET expressing tumors, showed relapsed disease (83% in negative p-MET samples, p=0.065), suggesting MET activation may revert the good prognosis linked to total MET expression. Conclusions: MET activation, results in a more aggressive phenotype in SCLC cells. PHA at MET inhibiting concentrations reverses this phenotype. In SCLC specimens, MET expression was more prevalent than p-MET and associated with raised prognosis. All these data suggest that studies with MET inhibitors should focus on p-MET positive SCLC.

[Table: see text]

A search for new MRI criteria for dissemination in space in subjects with a clinically isolated syndrome

The International Panel on the Diagnosis of Multiple Sclerosis (MS) incorporated the Barkhof/Tintoré (B/T) magnetic resonance criteria into their diagnostic scheme to provide evidence of dissemination in space of central nervous system lesions, a prerequisite for diagnosing MS in patients who present with clinically isolated syndromes (CIS). Although specific for MS, the B/T criteria were criticised for their low sensitivity and relative complexity in clinical use. We used lesion characteristics at onset from 349 CIS patients in logistic regression and recursive partitioning modelling in a search for simpler and more sensitive criteria, while maintaining current specificity. The resulting models, all based on the presence of periventricular and deep white matter lesions, performed roughly in agreement with the B/T criteria, but were unable to provide higher diagnostic accuracy based on information from a single scan. Apparently, findings from contrast-enhanced and follow-up magnetic resonance scans are needed to improve the diagnostic algorithm.

[Diffuse astrocytoma presenting as an optic-spinal syndrome]

INTRODUCTION

Spinal cord involvement is a rare presentation of grade II astrocytomas. Nevertheless, differentiation from inflammatory demyelinating diseases of the central nervous system can be challenging in some clinical situations. A patient with an optic-spinal syndrome due to a fibrillary astrocytoma is described.

CASE REPORT

A 32 years-old man was admitted to the hospital because of a subacute spinal cord syndrome. Brain MRI showed no abnormalities, and spinal MRI disclosed a cervical cord lesion suggestive of myelitis. Cerebrospinal fluid analysis revealed oligoclonal bands. Clinical improvement was observed after corticosteroid treatment. Three months later, the patient presented with binocular vision loss. A bilateral retrobulbar optic neuritis was suspected, and corticosteroid therapy was administered again. A new MRI with spectroscopy revealed an infiltrative lesion involving the right frontal lobe, optic chiasm, internal capsule, brainstem and cervical spinal cord, which was suggestive of low-grade astrocytoma. Brain biopsy confirmed the diagnosis of diffuse fibrillary astrocytoma.

CONCLUSION

Differential diagnosis between inflammatory and neoplastic lesions of the central nervous system requires close clinical-radiological follow-up. In this clinical situation, treatment response to corticosteroids and presence of oligoclonal bands in the cerebrospinal fluid may be not necessarily indicative of an inflammatory demyelinating process. Brain biopsy is often necessary for a definite diagnosis.

Proton MR spectroscopy improves discrimination between tumor and pseudotumoral lesion in solid brain masses

BACKGROUND AND PURPOSE

Differentiating between tumors and pseudotumoral lesions by conventional MR imaging may be a challenging question. This study aims to evaluate the potential usefulness and the added value that single-voxel proton MR spectroscopy could provide on this discrimination.

MATERIALS AND METHODS

A total of 84 solid brain lesions were retrospectively included in the study (68 glial tumors and 16 pseudotumoral lesions). Single-voxel spectra at TE 30 ms (short TE) and 136 ms (long TE) were available in all cases. Two groups were defined: "training-set" (56 cases) and "test-set" (28 cases). Tumors and pseudotumors were compared in the training-set with the Mann-Whitney U test. Ratios between resonances were defined as classifiers for new cases, and thresholds were selected with receiver operating characteristic (ROC) curves. The added value of spectroscopy was evaluated by 5 neuroradiologists and assessed with the Wilcoxon signed-rank test.

RESULTS

Differences between tumors and pseudotumors were found in myo-inositol (mIns); P < .01) at short TE, and N-acetylaspartate (NAA; P < .001), glutamine (Glx; P < .01), and choline (CHO; P < .05) at long TE. Classifiers suggested tumor when mIns/NAA ratio was more than 0.9 at short TE and also when CHO/NAA ratio was more than 1.9 at long TE. Classifier accuracy was tested in the test-set with the following results: short TE, 82% (23/28); long TE, 79% (22/28). The neuroradiologists' confidence rating of the test-cases on a 5-point scale (0-4) improved between 5% (from 2.86-3) and 27% (from 2.25-2.86) with spectroscopy (mean, 17%; P < .01).

CONCLUSIONS

The proposed ratios of mIns/NAA at short TE and CHO/NAA at long TE provide valuable information to discriminate between brain tumor and pseudotumor by improving neuroradiologists' accuracy and confidence.

Risk of symptomatic intracerebral hemorrhage in patients treated with intra-arterial thrombolysis

BACKGROUND

In intra-arterial (IA) thrombolysis trials, higher rates of symptomatic intracerebral haemorrhage (sICH) were found than in trials with intravenous (IV) recombinant tissue plasminogen activator (tPA); this observation could have been due to the inclusion of more severely affected patients in IA thrombolysis trials. In the present study, we investigated the rate of sICH in IA and combined IV + IA thrombolysis versus IV thrombolysis after adjusting for differences in clinical and MRI parameters.

METHODS

In this multicenter study, we systematically analyzed data from 645 patients with anterior-circulation strokes treated with either IV or IA thrombolysis within 6 h following symptom onset. Thrombolytic regimens included (1) IV tPA treatment (n = 536) and (2) IA treatment with either tPA or urokinase (n = 74) or (3) combined IV + IA treatment with either tPA or urokinase (n = 35).

RESULTS

44 (6.8%) patients developed sICH. sICH patients had significantly higher scores on the National Institutes of Health Stroke Scale (NIHSS) at admission and pretreatment DWI lesions. The sICH risk was 5.2% (n = 28) in IV thrombolysis, which is significantly lower than in IA (12.5%, n = 9) or IV + IA thrombolysis (20%, n = 7). In a binary logistic regression analysis including age, NIHSS score, time to thrombolysis, initial diffusion weighted imaging lesion size, mode of thrombolytic treatment and thrombolytic agent, the mode of thrombolytic treatment remained an independent predictor for sICH. The odds ratio for IA or IV + IA versus IV treatment was 3.466 (1.19-10.01, 95% CI, p < 0.05).

CONCLUSION

In this series, IA and IV + IA thrombolysis is associated with an increased sICH risk as compared to IV thrombolysis, and this risk is independent of differences in baseline parameters such as age, initial NIHSS score or pretreatment lesion size.

Will Rogers phenomenon in multiple sclerosis

OBJECTIVE

Using different criteria for classifying patients into various stages of a disease can modify the stage-specific prognosis, even though the overall disease course remains unchanged. This is known as the "Will Rogers phenomenon," precluding the use of historical controls for treatment trials. We assessed whether the Will Rogers phenomenon may affect multiple sclerosis (MS) prognosis when applying different diagnostic criteria.

METHODS

Patients with a clinically isolated syndrome (CIS) suggestive of MS were studied. After 1 year, each patient was classified as CIS or evolved to MS according to two diagnostic criteria (Poser and McDonald). The outcome for prognosis was the time to reach an Expanded Disability Status Scale score > or = 3.0.

RESULTS

309 patients were studied for a median period of 84 months. After 1 year, 16% of patients had MS according to Poser and 44% according to McDonald criteria. The probability to reach Expanded Disability Status Scale score > or = 3.0 at median follow-up was 11% in CIS patients according to Poser and 7% according to McDonald criteria; it was 46% in MS patients according to Poser and 27% acccording to McDonald criteria. The group with a discordant diagnosis had a worse prognosis than that of CIS patients according to both criteria (p = 0.01), but better than that of MS patients according to both criteria (p = 0.01).

INTERPRETATION

The use of different diagnostic criteria may generate spurious improvements in the medium-term prognosis of MS. This calls for caution in using historical controls for MS trials.

[Acute disseminated encephalomyelitis: study of factors involved in a possible development towards multiple sclerosis]

Acute disseminated encephalomyelitis (ADEM) is an uncommon disease characterized by inflammation and demyelination of the central nervous system (CNS). It typically occurs after a viral infection or vaccination and is more frequent in children. Its immediate and longterm prognosis is expected to be good (20% of cases with sequelae). Although ADEM is typically monophasic, occasional relapses may occur. Differential diagnosis, mostly in the early phases, is established with multiple sclerosis (MS), a chronic inflammatory demyelinating disease of the CNS that may have worse prognosis. Traditionally it has been believed that 10% of ADEM patients develop MS. However, this percentage could be higher according to several recently published clinical series. Some clinical and paraclinical patterns are considered to confer risk of developing MS when present in ADEM patients. Our study has aimed to: a) describe a series of 29 patients (22 children and 9 adults) admitted in our hospital and diagnosed of ADEM between 1990 and 2005; b) study those patients considered to have risk patterns of developing MS, and c) compare the child and adult populations of our series. After a median 55 month follow-up, 6 children (27%) and no adults developed MS. In our series, risk patterns for developing MS predicted conversion to MS more accurately in children than in adults. Eight patients (6 children and 2 adults) had sequelae, cognitive in 6 of them. Our work supports that also observed in recent publications: that both conversion to MS or presence of sequelae after an episode of ADEM are more frequent than traditionally considered.

MR imaging findings in 56 patients with Wernicke encephalopathy: nonalcoholics may differ from alcoholics

BACKGROUND AND PURPOSE

Wernicke encephalopathy (WE) is a severe neurologic disorder resulting from dietary vitamin B(1) deficiency. This study was undertaken to analyze and compare MR imaging findings and neurologic manifestations at clinical presentations of patients with WE with and without a history of alcohol abuse.

MATERIALS AND METHODS

WE patients were identified using diagnostic neurologic data bases. Fifty-six patients (29 females, 27 males) diagnosed between 1999 and 2008 with WE who improved within 1 month from the onset of thiamine administration were included in the analysis. Patients' records were reviewed for clinical manifestations and imaging studies' findings. MR imaging was performed in the acute phase of the disease at a field strength of 1T (16 patients) and 1.5T (40 patients). All MR images were of acceptable to good quality and were retrospectively reviewed. We compared imaging findings and clinical presentation in the alcoholic (AL) group versus the non-alcoholic (NA) group using the 2-tailed Fisher exact test and the Phi coefficient as appropriate.

RESULTS

Forty-three percent of the patients were in the AL group, whereas 57% were in the NA group. Eighty-nine percent showed changes in consciousness, 75% had ocular manifestations, and 54% had ataxia. On MR imaging, 80% of the patients had evidence of symmetric lesions in the medial thalami and in the periventricular region of the third ventricle; 59%, in the periaqueductal area; 45%, in the mamillary bodies; 36%, in the tectal plate; and 7%, in the periventricular gray matter located anteriorly to the fourth ventricle. Signal-intensity alterations in areas considered atypical for the disease were noted only in the NA group and always in association with the typical findings. Contrast enhancement of the thalamus and mamillary bodies was significantly associated with alcohol abuse.

CONCLUSIONS

Contrast enhancement in the mamillary bodies and thalamus is a typical finding of the disease in AL patients. Atypical MR imaging findings characterize NA patients.

Relationship between MRI lesion activity and response to IFN-beta in relapsing-remitting multiple sclerosis patients

OBJECTIVE

Our objective in this study is to evaluate whether brain magnetic resonance imaging (MRI) performed at interferon-beta (IFN-beta) onset and after 12 months allow us to identify relapsing-remitting multiple sclerosis (RRMS) patients with a disability increase in the first 2 years of therapy.

METHODS

This is a prospective and longitudinal study of patients with RRMS treated with IFN-beta. All patients included underwent brain MRI before the onset of therapy with IFN-beta and 12 months after. MRI measures (T2, unenhanced T1-weighted and gadolinium-enhancing T1-weighted brain lesion load, brain parenchymal fraction) were undertaken at baseline and after 12 months. The number of active lesions (new or enlarging T2 plus gadolinium-enhancing brain lesions) was also assessed on the 12 months MRI scan. Expanded Disability Status Scale (EDSS) was scored every 3 months. We defined an increase in disability as an increase of at least 1 EDSS point confirmed and sustained during the first 2 years of therapy with IFN-beta. Regression analysis was performed in order to identify MRI variables of response.

RESULTS

We included 152 patients who were followed-up for at least 2 years. After 2 years of therapy, 24 patients (16%) had an increase in disability. The logistic regression model showed that active lesions in the scan performed at 12 months were the most important factor related with the increase of disability after 2 years of therapy (odds ratio 8.3, 95% confidence interval 3.1-21.9; p < 0.0001).

CONCLUSIONS

In RRMS patients treated with IFN-beta the MRI changes occurring during the first year may have a prognostic value for identifying patients with a confirmed increase of disability after 2 years of therapy.

Predicting progression in primary progressive multiple sclerosis: a 10-year multicenter study

Rates of progression vary widely in primary progressive multiple sclerosis. This multicenter study aimed to identify predictors of progression over 10 years. A total of 101 patients who had been imaged at baseline and 2 years were scored on the expanded disability status scale after 10 years. Ordinal logistic regression identified the following independent variables that predicted progression: male sex, shorter disease duration, and slower timed walk test at baseline (best overall predictor), and deterioration in expanded disability status scale score and reduction in brain volume over 2 years. These predictors of long-term disability provide some insight into disease progression.

MR imaging findings in hepatic encephalopathy

The term hepatic encephalopathy (HE) includes a spectrum of neuropsychiatric abnormalities occurring in patients with liver dysfunction. Most cases are associated with cirrhosis and portal hypertension or portal-systemic shunts, but the condition can also be seen in patients with acute liver failure and, rarely, with portal-systemic bypass and no associated intrinsic hepatocellular disease. Although HE is a clinical condition, several neuroimaging techniques, particularly MR imaging, may eventually be useful for the diagnosis because they can identify and measure the consequences of central nervous system (CNS) increase in substances that under normal circumstances, are efficiently metabolized by the liver. Classic MR imaging abnormalities include high signal intensity in the globus pallidum on T1-weighted images, likely a reflection of increased tissue concentrations of manganese, and an elevated glutamine/glutamate peak coupled with decreased myo-inositol and choline signals on proton MR spectroscopy, representing disturbances in cell-volume homeostasis secondary to brain hyperammonemia. Recent data have shown that white matter abnormalities, also related to increased CNS ammonia concentration, can also be detected with several MR imaging techniques such as magnetization transfer ratio measurements, fast fluid-attenuated inversion recovery sequences, and diffusion-weighted images. All these MR imaging abnormalities, which return to normal with restoration of liver function, probably reflect the presence of mild diffuse brain edema, which seems to play an essential role in the pathogenesis of HE. It is likely that MR imaging will be increasingly used to evaluate the mechanisms involved in the pathogenesis of HE and to assess the effects of therapeutic measures focused on correcting brain edema in these patients.

Prognostic significance of blood pressure variability after thrombolysis in acute stroke

OBJECTIVE

To evaluate the impact of early blood pressure (BP) changes on diffusion-weighted imaging (DWI) lesion evolution and clinical outcome in patients with stroke treated with IV tissue plasminogen activator (tPA).

METHODS

We prospectively evaluated 80 patients with stroke with a documented middle cerebral artery occlusion treated with IV tPA. Multiple repeated systolic (SBP) and diastolic (DBP) BP measurements were obtained during 24 hours after admission. All patients underwent DWI, perfusion-weighted imaging, and magnetic resonance angiography before and 36-48 hours after thrombolysis. Recanalization was assessed on transcranial Doppler at 6 hours of stroke onset. NIH Stroke Scale scores were recorded at baseline and 24 hours. Modified Rankin Scale was used to assess 3-month outcome.

RESULTS

Recanalization occurred in 44 (55%) patients. BP variability, estimated as the SD of the mean, was associated with DWI lesion growth (r = 0.46, p = 0.0003 for SBP and r = 0.26, p = 0.02 for DBP), early clinical course (p = 0.06 for SBP and p = 0.01 for DBP), and 3-month outcome (p = 0.002 for SBP and 0.07 for DBP). However, the prognostic significance of BP changes differed depending on the presence of recanalization. SBP variability emerged as an independent predictor of DWI lesion growth (beta: 6.9; 95% CI, 3.2 to 10.7, p = 0.003) and worse stroke outcome (OR: 11; 95% CI: 2.2 to 56.1; p = 0.004) in patients without recanalization, but not in recanalized patients.

CONCLUSION

Blood pressure variability is associated with greater diffusion-weighted imaging lesion growth and worse clinical course in patients with stroke treated with IV tissue plasminogen activator. However, its impact varies depending on the occurrence of early recanalization after thrombolysis.

Risk for symptomatic intracerebral hemorrhage after thrombolysis assessed by diffusion-weighted magnetic resonance imaging

OBJECTIVE

The risk for symptomatic intracerebral hemorrhage (sICH) associated with thrombolytic treatment has not been evaluated in large studies using diffusion-weighted imaging (DWI). Here, we investigated the relation between pretreatment DWI lesion size and the risk for sICH after thrombolysis.

METHODS

In this retrospective multicenter study, prospectively collected data from 645 patients with anterior circulation stroke treated with intravenous or intraarterial thrombolysis within 6 hours (<3 hours: n = 320) after symptom onset were pooled. Patients were categorized according to the pretreatment DWI lesion size into three prespecified groups: small (< or =10 ml; n = 218), moderate (10-100 ml; n = 371), and large (>100 ml; n = 56) DWI lesions.

RESULTS

In total, 44 (6.8%) patients experienced development of sICH. The sICH rate was significantly different between subgroups: 2.8, 7.8, and 16.1% in patients with small, moderate, and large DWI lesions, respectively (p < 0.05). This translates to a 5.8 (2.8)-fold greater sICH risk for patients with large DWI lesions as compared with patients with small (or moderate) DWI lesions. The results were similar in the large subgroup (n = 536) of patients treated with intravenous tissue plasminogen activator. DWI lesion size remained an independent risk factor when including National Institutes of Health Stroke Scale, age, time to thrombolysis, and leukoariosis in a logistic regression analysis.

INTERPRETATION

This multicenter study provides estimates of sICH risk in potential candidates for thrombolysis. The sICH risk increases gradually with increasing DWI lesion size, indicating that the potential benefit of therapy needs to be balanced carefully against the risk for sICH, especially in patients with large DWI lesions.

Progression of symptomatic intracranial large artery atherosclerosis is associated with a proinflammatory state and impaired fibrinolysis

BACKGROUND AND PURPOSE

The molecular pathways involved in the progression of intracranial large artery atherosclerosis (ILA) are largely unknown. Our objective was to prospectively study the relationship between circulating levels of inflammatory markers and fibrinolysis inhibitors, and the risk of progression of symptomatic ILA.

METHODS

Seventy-five consecutive patients with first-ever symptomatic intracranial atherostenosis were studied. Blood levels of C-reactive protein (CRP), E-selectin, monocyte chemoattractant protein-1, intercellular adhesion molecule-1, matrix metalloproteinases 1, 2, 3, 8, 9, 10, and 13, plasminogen activator inhibitor-1 (PAI-1), and lipoprotein(a) were measured 3 months after the qualifying stroke or transient ischemic attack. Thereafter, patients underwent long-term transcranial Doppler follow-up to detect progression of ILA.

RESULTS

During a median follow-up time of 23 months, 25 (33%) patients showed ILA progression. Multivariable adjusted Cox regression models and Kaplan-Meier curves showed that high baseline level of CRP, E-selectin, intercellular adhesion molecule-1, matrix metalloproteinase 9, PAI-1, and lipoprotein(a) predicted ILA progression independently of vascular risk factors. Of them, only CRP (CRP>5.5 mg/L; HR, 5.4 [2.3 to 12.7]; P=0.0001) and PAI-1 (PAI-1>23.1 ng/mL; HR, 2.4 [1.0 to 5.8]; P=0.05) predicted ILA progression also independently of the other studied molecules.

CONCLUSIONS

Progression of symptomatic ILA is associated with a proinflammatory state, as reflected by high levels of inflammatory markers, and with defective fibrinolysis, as indicated by raised concentrations of endogenous fibrinolysis inhibitors.

Relating functional changes during hand movement to clinical parameters in patients with multiple sclerosis in a multi-centre fMRI study

We performed a prospective multi-centre study using functional magnetic resonance imaging (fMRI) to better characterize the relationships between clinical expression and brain function in patients with multiple sclerosis (MS) at eight European sites (56 MS patients and 60 age-matched, healthy controls). Patients showed greater task-related activation bilaterally in brain regions including the pre- and post-central, inferior and superior frontal, cingulate and superior temporal gyri and insula (P < 0.05, all statistics corrected for multiple comparisons). Both patients and healthy controls showed greater brain activation with increasing age in the ipsilateral pre-central and inferior frontal gyri (P < 0.05). Patients, but not controls, showed greater brain activation in the anterior cingulate gyrus and the bilateral ventral striatum (P < 0.05) with less hand dexterity. An interaction between functional activation changes in MS and age was found. This large fMRI study over a broadly selected MS patient population confirms that movement for patients demands significantly greater cognitive 'resource allocation' and suggests age-related differences in brain responses to the disease. These observations add to evidence that brain functional responses (including potentially adaptive brain plasticity) contribute to modulation of clinical expression of MS pathology and demonstrate the feasibility of a multi-site functional MRI study of MS.

A three-year, multi-parametric MRI study in patients at presentation with CIS

OBJECTIVES

To define the extent of overall brain damage in patients with clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS) and to identify non-conventional magnetic resonance (MR) metrics predictive of evolution to definite MS.

METHODS

Brain conventional and magnetization transfer (MT) MRI scans were obtained from 208 CIS patients and 55 matched healthy controls, recruited in four centres. Patients were assessed clinically at the time of MRI acquisition and after a median period of 3.1 years from disease onset. The following measures were derived: T2, T1 and gadolinium (Gd)- enhancing lesion volumes (LV), normalized brain volume (NBV), MTR histogram-derived quantities of the normal-appearing white matter (NAWM) and grey matter (GM).

RESULTS

During the follow-up, 43 % of the patients converted to definite MS. At baseline, a significant inter-centre heterogeneity was detected for T2 LV (p = 0.003), T1 LV (p = 0.006), NBV (p < 0.001) and MTR histogram-derived metrics (p < 0.001). Pooled average MTR values differed between CIS patients and controls for NAWM (p = 0.003) and GM (p = 0.01). Gdactivity and positivity of International Panel (IP) criteria for disease dissemination in space (DIS), but not NAWM and GM MTR and NBV, were associated with evolution to definite MS. The final multivariable model retained only MRI IP criteria for DIS (p = 0.05; HR = 1.66, 95 % CI = 1.00-2.77) as an independent predictor of evolution to definite MS.

CONCLUSIONS

Although irreversible tissue injury is present from the earliest clinical stages of MS, macroscopic focal lesions but not "diffuse" brain damage measured by MTR are associated to an increased risk of subsequent development of definite MS in CIS patients.