On the dependence of quantitative diffusion-weighted imaging on scanner system characteristics and acquisition parameters: A large multicenter and multiparametric phantom study with unsupervised clustering analysis.

PURPOSE: The purpose of this multicenter phantom study was to exploit an innovative approach, based on an extensive acquisition protocol and unsupervised clustering analysis, in order to assess any potential bias in apparent diffusion coefficient (ADC) estimation due to different scanner characteristics. Moreover, we aimed at assessing, for the first time, any effect of acquisition plan/phase encoding direction on ADC estimation. METHODS: Water phantom acquisitions were carried out on 39 scanners. DWI acquisitions (b-value = 0-200-400-600-800-1000 s/mm2) with different acquisition plans (axial, coronal, sagittal) and phase encoding directions (anterior/posterior and right/left, for the axial acquisition plan), for 3 orthogonal diffusion weighting gradient directions, were performed. For each acquisition setup, ADC values were measured in-center and off-center (6 different positions), resulting in an entire dataset of 84 × 39 = 3276 ADC values. Spatial uniformity of ADC maps was assessed by means of the percentage difference between off-center and in-center ADC values (Δ). RESULTS: No significant dependence of in-center ADC values on acquisition plan/phase encoding direction was found. Ward unsupervised clustering analysis showed 3 distinct clusters of scanners and an association between Δ-values and manufacturer/model, whereas no association between Δ-values and maximum gradient strength, slew rate or static magnetic field strength was revealed. Several acquisition setups showed significant differences among groups, indicating the introduction of different biases in ADC estimation. CONCLUSIONS: Unsupervised clustering analysis of DWI data, obtained from several scanners using an extensive acquisition protocol, allows to reveal an association between measured ADC values and manufacturer/model of scanner, as well as to identify suboptimal DWI acquisition setups for accurate ADC estimation.

Relationship Between Physical Activity, Tic Severity and Quality of Life in Children with Tourette Syndrome.

OBJECTIVE: To examine the relationship between physical activity, tic severity and quality of life (QoL) in children and adolescents with persistent tic disorder and Tourette Syndrome. METHOD: Baseline data was examined from a larger randomized controlled trial (Clinicaltrials.gov NCT02153463). Physical activity was assessed via pedometers with daily step count recorded. Tic severity (assessed via Yale Global Tic Severity Scale or YGTSS) and QoL (assessed via PEDs QL 4.0) were compared between those more physically active (≥12,000 steps/day) and less physically active (<12,000 steps/day). RESULTS: Thirteen children participated; four had ≥12,000 steps/day and nine had <12,000 steps/day. The active group had a lower total tic severity (p = 0.02), and total YGTSS score (p=0.01). The vocal tic severity score was lower in the active group (p=0.02). Motor tic severity was not different amongst the two groups. For Peds QL scores, the active group performed better in physical functioning (p=0.01), social functioning (p=0.03), school functioning (p=0.02), psychosocial functioning (p=0.03) and total PEDs QL score (p=0.01). CONCLUSIONS: Higher physical activity levels are associated with lower vocal tic severity and improved aspects of quality of life. Further research is needed to determine the utility of physical activity as therapy for tics.

OBJECTIF: Examiner la relation entre l'activité physique, la gravité des tics et la qualité de vie (QdV) des enfants et adolescents souffrant d'un trouble de tics persistants et du syndrome de Tourette. MÉTHODE: Les données de base ont été examinées d'après un essai randomisé contrôlé plus vaste (Clinicaltrials.gov NCT02153463). L'activité physique a été évaluée par des podomètres enregistrant le compte de pas quotidien. La gravité des tics (évaluée par l'échelle globale de gravité des tics de Yale ou la YGTSS) et la QdV (évaluée par l'inventaire de la qualité de vie des jeunes adultes, PEDs QL 4.0) ont été comparées entre les enfants plus actifs physiquement (≥12 000 pas/jour) et les enfants moins actifs physiquement (<12 000 pas/jour). RÉSULTATS: Treize enfants ont participé; 4 avaient ≥12 000 pas/jour et 9 avaient <12 000 pas/jour. Le groupe actif avait un total plus faible de gravité des tics (p = 0,02), et un score total moindre à la YGTSS (p = 0,01). Le score à la gravité des tics sonores était plus faible dans le groupe actif (p = 0,02). La gravité des tics moteurs n'était pas différente chez les 2 groupes. Pour les scores à la Peds QL, le groupe actif a eu un meilleur rendement au fonctionnement physique (p = 0,01), au fonctionnement social (p = 0,03), au fonctionnement scolaire (p = 0,02), au fonctionnement psychosocial (p = 0,03) et au score total de la PEDs QL (p = 0,01). CONCLUSIONS: Des niveaux supérieurs d'activité physique sont associés à une gravité plus faible des tics sonores et à des aspects améliorés de la qualité de vie. Il faut plus de recherche pour déterminer l'utilité de l'activité physique comme thérapie pour les tics.

Dependence of apparent diffusion coefficient measurement on diffusion gradient direction and spatial position - A quality assurance intercomparison study of forty-four scanners for quantitative diffusion-weighted imaging.

PURPOSE: To propose an MRI quality assurance procedure that can be used for routine controls and multi-centre comparison of different MR-scanners for quantitative diffusion-weighted imaging (DWI). MATERIALS AND METHODS: 44 MR-scanners with different field strengths (1 T, 1.5 T and 3 T) were included in the study. DWI acquisitions (b-value range 0-1000 s/mm2), with three different orthogonal diffusion gradient directions, were performed for each MR-scanner. All DWI acquisitions were performed by using a standard spherical plastic doped water phantom. Phantom solution ADC value and its dependence with temperature was measured using a DOSY sequence on a 600 MHz NMR spectrometer. Apparent diffusion coefficient (ADC) along each diffusion gradient direction and mean ADC were estimated, both at magnet isocentre and in six different position 50 mm away from isocentre, along positive and negative AP, RL and HF directions. RESULTS: A good agreement was found between the nominal and measured mean ADC at isocentre: more than 90% of mean ADC measurements were within 5% from the nominal value, and the highest deviation was 11.3%. Away from isocentre, the effect of the diffusion gradient direction on ADC estimation was larger than 5% in 47% of included scanners and a spatial non uniformity larger than 5% was reported in 13% of centres. CONCLUSION: ADC accuracy and spatial uniformity can vary appreciably depending on MR scanner model, sequence implementation (i.e. gradient diffusion direction) and hardware characteristics. The DWI quality assurance protocol proposed in this study can be employed in order to assess the accuracy and spatial uniformity of estimated ADC values, in single- as well as multi-centre studies.

A straightforward multiparametric quality control protocol for proton magnetic resonance spectroscopy: Validation and comparison of various 1.5 T and 3 T clinical scanner systems.

PURPOSE: The aim of this study was to propose and validate across various clinical scanner systems a straightforward multiparametric quality assurance procedure for proton magnetic resonance spectroscopy (MRS). METHODS: Eighteen clinical 1.5 T and 3 T scanner systems for MRS, from 16 centres and 3 different manufacturers, were enrolled in the study. A standard spherical water phantom was employed by all centres. The acquisition protocol included 3 sets of single (isotropic) voxel (size 20 mm) PRESS acquisitions with unsuppressed water signal and acquisition voxel position at isocenter as well as off-center, repeated 4/5 times within approximately 2 months. Water peak linewidth (LW) and area under the water peak (AP) were estimated. RESULTS: LW values [mean (standard deviation)] were 1.4 (1.0) Hz and 0.8 (0.3) Hz for 3 T and 1.5 T scanners, respectively. The mean (standard deviation) (across all scanners) coefficient of variation of LW and AP for different spatial positions of acquisition voxel were 43% (20%) and 11% (11%), respectively. The mean (standard deviation) phantom T2values were 1145 (50) ms and 1010 (95) ms for 1.5 T and 3 T scanners, respectively. The mean (standard deviation) (across all scanners) coefficients of variation for repeated measurements of LW, AP and T2 were 25% (20%), 10% (14%) and 5% (2%), respectively. CONCLUSIONS: We proposed a straightforward multiparametric and not time consuming quality control protocol for MRS, which can be included in routine and periodic quality assurance procedures. The protocol has been validated and proven to be feasible in a multicentre comparison study of a fairly large number of clinical 1.5 T and 3 T scanner systems.

Gamma camera calibrations for the Italian multicentre study for lesion dosimetry in 223Ra therapy of bone metastases.

PURPOSE: The aim was to calibrate gamma cameras in the framework of the Italian multicentre study for lesion dosimetry in 223Ra therapy of bone metastases. Equipments of several manufacturers and different models were used. METHODS: Eleven gamma cameras (3/8- and 5/8-inch crystal) were used, acquiring planar static images with double-peak (82 and 154keV, 20% wide) and MEGP collimator. The sensitivity was measured in air, varying source-detector distance and source size. Transmission curves were measured, calculating the parameters used for attenuation/scatter correction with the pseudo-extrapolation number method, and assessing their variations with the source size. RESULTS: Values of the calibration factor (geometric mean of both detector sensitivities) ranged from 41.1 to 113.9cps/MBq. For the smallest source (diameter of 3.5cm), the calibration factor decrease ranged from -30% to -4%, highlighting the importance of partial volume effects according to the equipment involved. The sensitivity variation with the source-detector distance, with respect to the 15cm-value, reached 10% (in absolute value) in the range 5-30cm, but fixing the distance between the two heads, the calibration factor variation with the distance from the midline was within 3.6%. Appreciable variation of the transmission curves with the source size were observed, examining the results obtained with six gamma cameras. CONCLUSION: Assessments of sensitivity and transmission curve variations with source size should be regularly implemented in calibration procedures. The results of this study represent a useful compendium to check the obtained calibrations for dosimetric purposes.

Blood pressure control and treatment adherence in hypertensive patients with metabolic syndrome: protocol of a randomized controlled study based on home blood pressure telemonitoring vs. conventional management and assessment of psychological determinants of adherence (TELEBPMET Study).

BACKGROUND: Inadequate blood pressure control and poor adherence to treatment remain among the major limitations in the management of hypertensive patients, particularly of those at high risk of cardiovascular events. Preliminary evidence suggests that home blood pressure telemonitoring (HBPT) might help increasing the chance of achieving blood pressure targets and improve patient's therapeutic adherence. However, all these potential advantages of HBPT have not yet been fully investigated. METHODS/DESIGN: The purpose of this open label, parallel group, randomized, controlled study is to assess whether, in patients with high cardiovascular risk (treated or untreated essential arterial hypertension--both in the office and in ambulatory conditions over 24 h--and metabolic syndrome), long-term (48 weeks) blood pressure control is more effective when based on HBPT and on the feedback to patients by their doctor between visits, or when based exclusively on blood pressure determination during quarterly office visits (conventional management (CM)). A total of 252 patients will be enrolled and randomized to usual care (n = 84) or HBPT (n = 168). The primary study endpoint will be the rate of subjects achieving normal daytime ambulatory blood pressure targets (< 135/85 mmHg) 24 weeks and 48 weeks after randomization. In addition, the study will assess the psychological determinants of adherence and persistence to drug therapy, through specific psychological tests administered during the course of the study. Other secondary study endpoints will be related to the impact of HBPT on additional clinical and economic outcomes (number of additional medical visits, direct costs of patient management, number of antihypertensive drugs prescribed, level of cardiovascular risk, degree of target organ damage and rate of cardiovascular events, regression of the metabolic syndrome). DISCUSSION: The TELEBPMET Study will show whether HBPT is effective in improving blood pressure control and related medical and economic outcomes in hypertensive patients with metabolic syndrome. It will also provide a comprehensive understanding of the psychological determinants of medication adherence and blood pressure control of these patients. TRIAL REGISTRATION: Clinical Trials.gov: NCT01541566.

Blocking the RAAS at different levels: an update on the use of the direct renin inhibitors alone and in combination.

The renin-angiotensin-aldosterone system (RAAS), an important regulator of blood pressure and mediator of hypertension-related complications, is a prime target for cardiovascular drug therapy. Angiotensin-converting enzyme inhibitors (ACEIs) were the first drugs to be used to block the RAAS. Angiotensin II receptor blockers (ARBs) have also been shown to be equally effective for treatment. Although these drugs are highly effective and are widely used in the management of hypertension, current treatment regimens with ACEIs and ARBs are unable to completely suppress the RAAS. Combinations of ACEIs and ARBs have been shown to be superior than to either agent alone for some, but certainly not all, composite cardiovascular and kidney outcomes, but dual RAAS blockade with the combination of an ACEI and an ARB is sometimes associated with an increase in the risk for adverse events, primarily hyperkalemia and worsening renal function. The recent introduction of the direct renin inhibitor, aliskiren, has made available new combination strategies to obtain a more complete blockade of the RAAS with fewer adverse events. Renin system blockade with aliskiren and another RAAS agent has been, and still is, the subject of many large-scale clinical trials and furthermore, is already available in some countries as a fixed combination.

Effectiveness of barnidipine 10 or 20 mg plus losartan 50-mg combination versus losartan 100-mg monotherapy in patients with essential hypertension not controlled by losartan 50-mg monotherapy: A 12-week, multicenter, randomized, open-label, parallel-group study.

BACKGROUND: Increasing the dose or adding a second antihypertensive agent are 2 possible therapeutic choices when blood pressure (BP) is poorly controlled with monotherapy. OBJECTIVE: This study investigated the effectiveness and tolerability of barnidipine 10 or 20 mg added to losartan 50 mg versus losartan 100 mg alone in patients with mild to moderate essential hypertension whose BP was uncontrolled by losartan 50-mg monotherapy. METHODS: This was a 12-week, multicenter, randomized, open-label, parallel-group study. Eligible patients (aged 30-74 years) had uncontrolled hypertension, defined as office sitting diastolic BP (DBP) > or =90 mm Hg and/or systolic BP (SBP) > or =140 mm Hg, and mean daytime DBP > or =85 mm Hg and/or SBP > or =135 mm Hg. All were being treated with losartan 50 mg at enrollment. After a 1-week run-in period while taking losartan 50 mg, patients were randomly assigned to 6 weeks of treatment with open-label barnidipine 10 mg plus losartan 50 mg or losartan 100-mg monotherapy. At the end of this period, patients with uncontrolled BP had barnidipine doubled to 20 mg and continued for an additional 6 weeks, whereas patients not achieving control on treatment with losartan 100 mg were discontinued. Office BP was measured at each visit, whereas 24-hour ambulatory BP monitoring (ABPM) was performed at randomization and at the final visit (ie, after 12 weeks of treatment, or at 6 weeks for patients not controlled on losartan 100 mg). The intent-to-treat population included all randomized patients who received at least one dose of study treatment and had valid ABPM recordings at baseline and the final visit. The primary end point was the change in daytime DBP between baseline and 12 weeks of treatment, compared between the combination treatment and monotherapy. Adverse events (AEs) were evaluated during each study visit. RESULTS: A total of 93 patients were enrolled (age range, 30-75 years; 60% [56/93] men). After the 1-week run-in period, 68 patients were randomly assigned to 6 weeks of treatment with open-label barnidipine 10 mg plus losartan 50 mg (n = 34) or losartan 100-mg monotherapy (n = 34). A total of 53 patients were evaluable (barnidipine plus losartan, n = 28; losartan, n = 25). After 6 weeks of treatment, 18 patients in the combination treatment group (64.3%) had their dose of barnidipine doubled from 10 to 20 mg because BP was not normalized by treatment, whereas 8 patients in the losartan group (32.0%) were discontinued for the same reason. The between-treatment difference (losartan alone - combination treatment) for changes from baseline in daytime DBP was -1.7 mm Hg (95% CI, -5.8 to 2.4 mm Hg; P = NS). A similar result was observed for daytime SBP (-3.2 mm Hg; 95% CI, -8.1 to 1.7 mm Hg; P = NS). Likewise, no significant differences were found for nighttime values (mean [95% CI] DBP, 0.5 mm Hg [-3.7 to 4.7 mm Hg]; SBP, 1.5 mm Hg [-4.1 to 7.1 mm Hg]) or 24-hour values (DBP, -0.9 mm Hg [-4.8 to 2.9 mm Hg]; SBP, -1.6 mm Hg [-5.9 to 2.7 mm Hg]). Combination treatment was associated with a significantly higher rate of SBP responder patients (ie, <140 mm Hg or a reduction of > or =20 mm Hg) compared with monotherapy (82.1% [23/28] vs 56.0% [14/25]; P = 0.044). Drug-related AEs were reported in 4 patients taking combination treatment (total of 7 AEs, including 2 cases of peripheral edema and 1 each of tachycardia, atrial flutter, tinnitus, confusion, and polyuria) and in 2 patients taking losartan alone (total of 2 AEs, both tachycardia). CONCLUSIONS: This open-label, parallel-group study found that there was no significant difference in the BP-lowering effect of barnidipine 10 or 20 mg in combination with losartan 50 mg compared with losartan 100-mg monotherapy in these patients with essential hypertension previously uncontrolled by losartan 50-mg monotherapy. However, the percentage of responders for SBP was significantly higher with the combination. Both treatments were generally well tolerated. European Union Drug Regulating Authorities Clinical Trials (EudraCT) no. 2006-001469-41.

Role of valsartan, amlodipine and hydrochlorothiazide fixed combination in blood pressure control: an update.

The treatment of moderate or severe hypertension in most cases requires the contemporaneous use of multiple antihypertensive agents. The most available two-drug combinations have an agent that addresses renin secretion and another one that is statistically more effective in renin-independent hypertension. The practice of combining agents that counteract different mechanisms is the most likely explanation for the fact that most available two-drug combinations have an agent that addresses renin secretion (beta-blocker, angiotensin converting enzyme inhibitor, angiotensin II receptor blocker or direct renin inhibitor) and another one that is more effective in renin-independent hypertension (diuretic, dihydropyridine or non-dihydropyridine calcium channel blocker). Based on these considerations, addition of hydrochlorothiazide to the combination of an antagonist of the renin-angiotensin system with a calcium channel blocker would constitute a logical approach. Inclusion of a diuretic in the triple combination is based on the evidence that these agents are effective and cheap, enhance the effect of other antihypertensive agents, and add a specific effect to individuals with salt-sensitivity of blood pressure. The benefit of triple combination therapy with amlodipine, valsartan and hydrochlorothiazide over its dual component therapies has been demonstrated, and the use of a single pill will simplify therapy resulting in better blood pressure control.

New strategies and drugs in the treatment of hypertension: monotherapy or combination?

Hypertension is one of the major risk factors associated with cardiovascular diseases. A range of blood pressure-lowering agents is available including diuretics, alpha- and beta-blockers, aldosterone antagonists, calcium-channel blockers (CCB), angiotensin-converting enzyme inhibitors (ACEI), angiotensin II receptor blockers (ARB) and direct renin inhibitors (DRI). Most patients require two or more medications to control their blood pressures within normal ranges. When high blood pressure cannot be controlled by low-dose monotherapy, physicians employ either high-dose monotherapy or combination therapy. High-dose ARB monotherapy is more effective for reducing proteinuria against low-dose ARB monotherapy or CCBs. Combination therapy is recommended for hypertension patients to facilitate prompt maintenance of blood pressure. Single-pill combination therapy simplifies treatment and optimizes long-term compliance. Thiazide diuretics such as hydrochlorothiazide (HCTZ), alone or in combination are still widely used as first-line hypertension treatment. Recent studies have shown that double (CCB+ARBs) or triple (CCB+ARBs+HCTZ) combination therapies have a greater lowering efficacy and are better tolerated. Moreover, the use of DRIs has been patented and proven effective in selected categories of hypertensive patients with or without concomitant target organ damage (TOD).

Olmesartan medoxomil: recent clinical and experimental acquisitions.

Angiotensin II is a vasoactive hormone of the renin-angiotensin system and plays an important role in the pathophysiology of several organ damages. Angiotensin II receptor blockers have been shown to be effective in treating both hypertension and connected organ damages. It is well known that although the angiotensin II receptor blockers have structural and pharmacokinetic differences, few pharmacological differences separate them. One of these is the degree of binding to the angiotensin II receptor type 1 compared with the angiotensin II receptor type 2; olmesartan medoxomil exhibits more than a 12,500-fold greater affinity for the angiotensin II receptor type 1 receptor than for the angiotensin II receptor type 2, making it theoretically the second most potent agent. However, olmesartan's excellent receptor interaction is based on the combination of several specific pharmacokinetic factors. Potential advantages of this drug include once-daily dosing, a very low incidence of significant adverse reactions and/or events and a well-tolerated side effect profile. Nowadays, we have a lot of information about the pharmacology, antihypertensive efficacy and safety of olmesartan medoxomil, to further extend many clinical studies are still continuing to evaluate the potential benefits of high dosages and/or combination of this molecule.

Implantable cardioverter-defibrillator lead infection detected by 99mTc-sulesomab single-photon emission computed tomography/computed tomography 'fusion' imaging.

We describe a case of implantable cardioverter-defibrillator (ICD) lead infection that was diagnosed by means of sulesomab imaging whereas ultrasound examinations were inconclusive. Nuclear techniques may be helpful in such, not infrequent, settings.

Retears of postoperative knee meniscus: findings on magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) by using low and high field magnets.

PURPOSE: The purpose of this study was to determine the diagnostic performance of magnetic resonance (MR) obtained with intra-articular contrast medium in the evaluation of recurrent meniscal tears using low-field extremity-only and high-field whole-body magnets. MATERIALS AND METHODS: Postoperative standard MR examinations and MR arthrographies of 95 knees were reviewed. Patients experiencing pain and disability after meniscal repair underwent standard MR and MR arthrography (Gadoterate meglumine 0.0025 mmol/ml) on both a 0.2-T and 1.5-T magnet. In 52 of 95 patients, second-look arthroscopy was performed; in the remaining 43 of 95 patients, clinical follow-up was used as the standard of reference. Sensitivity, specificity, positive and negative predictive values as well as accuracy of MRI/MR arthrographic signs as meniscal morphologic changes and the presence of contrast medium tracking into the tear at T1- and T2-weighted sequences in the detection of recurrent meniscal tears were determined. RESULTS: All MR and MR arthrograpic signs were sensitive in the detection of recurrent tears (range 80-91%). Abnormal meniscal morphology had low specificity [26% (13/50)] for both the 0.2-T and 1.5-T scanner, whereas accuracy was 55% (52/95) and 57% (54/95), respectively. The presence of contrast medium within the meniscus substance on T2-weighted images had higher value of specificity [84% (42/50)] and accuracy [84% (80/95)] by using low field strength magnet than by using high field strength magnet [74% (37/50) and 81% (77/95), respectively]. Whereas, the increased intrameniscal signal intensity extending to the meniscal surface at T1-weighted sequences after intra-articular contrast medium administration had lower specificity and accuracy on 0.2-T images [84% (42/50) and 82% (78/95), respectively] than on 1.5-T images [90% (45/50) and 88% (84/95), respectively]. CONCLUSION: A diagnosis of recurrent meniscal tear in a previously arthroscopically repaired meniscus can be made both on 0.2-T and 1.5-T magnets on the basis of increased signal on T2-weighted and T1-weighted images in the presence of intra-articular contrast material.

Anti-interferon antibodies in multiple sclerosis. Molecular basis and their impact on clinical efficacy.

Low levels of naturally-occurring, high-affinity antibodies directed against cytokines can be found in the circulation of individuals who have never been exposed to exogenously-supplied cytokines. These antibodies are thought to play a regulatory role in the intensity and duration of immune response. Interferon (IFN) beta has been shown to attenuate both relapsing-remitting multiple sclerosis (MS) and secondary progressive MS in several well-powered, randomized, controlled clinical trials. IFN therapy can induce the production of anti-IFN neutralizing antibodies (NAb), usually in the second 6 months of treatment, in 3 to 45% of treated patients. This variation in the proportion of NAb-positive patients is probably due to the immunogenicity of different formulations of IFN beta, as well as the assay used, which are not currently standardized. The occurrence of NAb appears to be directly correlated with the dose of therapeutic IFN administered, up to a certain dose threshold. If the dose is increased beyond this threshold, the levels of NAb decrease. The biological significance of anti-IFN NAb is not yet known, nor has it been proven conclusively that they affect the clinical response to IFN beta therapy. The presence of NAb is therefore not an indication that treatment should be changed. Indeed, any treatment decision should be based only on the clinical response to therapy.

High-dose, frequently administered interferon beta therapy for relapsing-remitting multiple sclerosis must be maintained over the long term: the interferon beta dose-reduction study.

Long-term trials have demonstrated the continued efficacy of interferon (IFN) beta treatment in patients with relapsing-remitting (RR) multiple sclerosis (MS) during prolonged administration. The objective of the work was to evaluate the effects of reducing IFN beta administration frequency and total weekly dose in patients with RR MS who have achieved clinical and MRI disease activity stabilization during long-term IFN beta-1b treatment. Prospective 1-year follow-up of 27 RR MS patients on long-term 250 microg every other day (standard dose) IFN beta-1b treatment were randomized either to gradually reduce dose to 30 microg once-a-week IFN beta-1a (13 patients), or to continue on IFN beta-1b standard dose (14 patients). We found significant differences in the two group of patients. In the group of patients continuously treated with IFN beta-1b standard dose, 79% remained relapse free compared to 23% in the group receiving once-weekly IFN beta-1a (p=0.006). The number of patients without new PD/T2 lesions was higher in the group of patients continuously treated with IFN beta-1b standard dose (77%) compared to the once-weekly IFN beta-1a group (23%) (p=0.04). IFN beta is a long-term treatment for MS. The reduction of IFN beta-1b administration frequency and dose is not advisable even in patients free from clinical and MRI disease activity for many years.