Localised proton magnetic resonance spectroscopy of the brain after perinatal hypoxia: a preliminary report

Objectives. Perinatal hypoxic ischaemic injury is a significant cause of neurodevelopmental impairment. The aim of this study was to evaluate localised proton magnetic resonance spectroscopy (¹H-MRS) after birth asphyxia. Materials and methods. Thirty newborn infants suspected of having perinatal asphyxia (Apgar score < 3) were studied. The mean gestational age was 37 weeks, mean age at the MR examination was 18 days and mean weight was 2.9 kg. A 1.5-T unit was used for imaging and spectroscopy. None of the babies had mechanically assisted ventilation. No sedation was used. Axial T1-weighted and T2-weighted images were obtained. ¹H-MRS was recorded in a single voxel, localised in white matter, using a STEAM sequence. Results. Image quality was good in 25 of 30 babies. ¹H-MRS was performed in 19 of 30 subjects, with adequate quality in 16. Choline, creatine/phosphocreatine and N-acetylaspartate peaks and peak-area ratios were analysed. Lactate was detected in four infants. The N-acetylaspartate/choline ratio was lower in infants with an impaired neurological outcome, but the difference was not statistically significant. Conclusions. This study suggests that ¹H-MRS may be useful for assessing cerebral metabolism in the neonate. A raised lactate level and decreased N-acetylaspartate/choline ratio may be predictive of a poor outcome. However, in our experience this method is limited by the difficulty in performing the examination during the first hours after birth in critically ill babies, the problems related to use of a monovoxel sequence, the dispersion of the ratios and the lack of determination of the absolute concentration of the metabolites. Received: 30 March 1998 Accepted: 24 September 1998     

Use of localized proton nuclear magnetic resonance spectroscopy in Canavan's disease

Canavan's disease is characterized by megalencephaly, leukodystrophy and early motor and mental retardation. On computerized tomography and magnetic resonance imaging, severe changes compatible with white matter disease due to demyelination is observed. It has been demonstrated that urinary N-acetylaspartate levels are increased because of a deficiency of aspartoacylase (N-acyl-L-aspartate aminohydrolase) in these patients. In this study, with the use of proton nuclear magnetic resonance spectroscopy, we were able to demonstrate elevated levels of N-acetylaspartate compared to choline and creatine in the frontal region white matter of three patients. The in vivo measurement of N-acetylaspartate, choline and creatine in the brain by magnetic resonance spectroscopy offers an additional noninvasive diagnostic test for establishing the diagnosis of Canavan's disease.     

中重度肥胖儿童脑代谢的质子磁共振波谱变化

目的探讨肥胖儿童额叶和海马感兴趣区的脑代谢特征。方法对象为2005年安徽省肥胖儿童夏令营小学生。分别对9例肥胖(肥胖组)及其配对的体质量健康儿童(健康对照组)进行测量(身高、体质量、腰围、臀围)和瑞文推理测验;双能X线吸收仪(DXA)测定全身体脂百分比;采用氢质子磁共振波谱(1H-MRS)检测额叶、海马部位脑代谢特点。结果1.肥胖组额叶部位N-乙酰天门冬氨酸(NAA)、额叶胆碱(Cho)、额叶肌酸(Cr)水平均显著低于健康对照组(126.88、80.38、53.13vs160.5、101.63、71.5)(Pa<0.05);2.肥胖组额叶NAA/Cr比高于健康对照组;海马部位NAA、Cr、NAA/Cr、Cho均较健康对照组高,但均无统计学差异(Pa>0.05)。结论中重度肥胖儿童额叶NAA减低表明额叶神经元数量减少,Cho减低提示中重度肥胖可能影响了儿童白质髓鞘化过程,造成白质髓鞘化过程慢于对照组;而Cr减低表明肥胖儿童额叶代谢低下。     

Proton MR spectroscopy in three children with Tay-Sachs disease

Background: Tay-Sachs disease is an inherited metabolic disease caused by the accumulation of GM₂ gangliosides in the central nervous system. Deficiency of hexosaminidase A leads to the accumulation of gangliosides in neurons, axons and glial cells. Objective: To present the cranial MRI and proton MR spectroscopy findings of children of Tay-Sachs disease. Materials and methods: Three children aged 10, 20 and 21 months were examined. Results: On T2-weighted MR images there were hyperintense signal changes in the basal ganglia and cerebral white matter. MR spectroscopy demonstrated an increase in myoinositol/creatine and choline/creatine ratios with a decrease in the N-acetyl aspartate/creatine ratio. Conclusions: The spectroscopy findings support demyelination, gliosis and neuronal loss in the neuropathological process of Tay-Sachs disease.     

Proton magnetic resonance spectroscopy: normal findings in the cerebellar hemisphere in childhood

BACKGROUND: The cerebellar hemispheres (CER) are different from the supratentorial white and gray matter embryologically, in cytoarchitecture, and probably in metabolic activity. Proton magnetic resonance spectroscopy ((1)H MRS) can provide a noninvasive biochemical analysis of this region. OBJECTIVE: To study, with (1)H MRS, metabolite concentrations in CER as a function of age and compare these metabolic data with those of parietoccipital white matter (PO WM) in healthy children. MATERIALS AND METHODS: Using single-voxel (1)H MRS, we studied 37 volunteers (3-18 years) with normal MRI scans of the brain. (1)H MRS was performed using the PRESS technique in CER and PO WM. The NAA/Cr, Cho/Cr, NAA/H(2)O, Cr/H(2)O, and Cho/H(2)O ratios were analyzed as a function of age. Metabolic data from these regions were compared. RESULTS: The NAA/Cr ratio tended to increase with age in CER. Mean NAA/Cr and Cho/Cr ratios were found to be lower in CER than in PO WM. Mean NAA/H(2)O, Cr/H(2)O, and Cho/H(2)O ratios in CER were higher than in the PO WM. CONCLUSION: Our data confirm the regional variations between CER and PO WM metabolite ratios, and demonstrate a tendency of age-dependent change of the NAA/Cr ratio in CER. The creatine concentration was significantly higher in the cerebellum than in the PO WM.     

Cardiac involvement in mucopolysaccharidoses: effects of allogeneic bone marrow transplantation.

Echocardiography was performed in 16 children undergoing bone marrow transplantation (BMT) for mucopolysaccharidoses. Cardiac involvement before BMT was detected in seven (44%). One year after BMT (11 patients/five with cardiac involvement), left ventricular restriction resolved in 2/3 patients and hypertrophy in one. In the remainder, at mean follow up of 2.5 years, no progression of preexisting or development of new cardiac involvement was noted. It is concluded that in a significant proportion of patients with mucopolysaccharidoses, cardiac involvement improved after BMT.     

Value of (1)H-MRS using different echo times in neonates with cerebral hypoxia-ischemia

Previous studies have shown altered brain metabolism after cerebral hypoxia-ischemia, using magnetic resonance spectroscopy with echo times (TE) of 272 and 136 ms, based on peak-area or peak-height ratios. The present study examined the additional value of proton magnetic resonance spectroscopy with a short TE (31 ms) to predict a poor outcome in neonates with brain hypoxia-ischemia. Studies were performed in 21 full-term neonates with perinatal asphyxia in a 1.5 tesla magnetic field. Proton magnetic resonance spectroscopy was performed in a single volume of interest including the basal ganglia. TE of 272, 136 and 31 ms were used. After curve-fitting procedures, peak-areas as well as peak-height ratios of different brain metabolites were calculated, comparing patients with a poor versus a good outcome. Seven neonates out of 21 had a poor outcome. Neonates with a poor outcome showed a significantly lower N:-acetylaspartate/choline (NAA/Cho) and a significantly raised lactate/NAA (Lac/NAA) ratio using TE of 272 and 136 ms. Using a TE of 31 ms, no differences were found in glutamate/NAA (Glx/NAA), Glx/Cho, myo-inositol/NAA (mI/NAA), and mI/Cho ratios between neonates with a good and those with a poor outcome. Highest predictive values could be achieved for NAA/Cho with a TE of 136 ms. We conclude that low NAA/Cho and high Lac/NAA ratios predict a poor outcome in neonates with cerebral hypoxia-ischemia. TE of 272 and 136 ms have a better predictive value than a TE of 31 ms.     

MR imaging of glioblastoma in children: usefulness of diffusion/perfusion-weighted MRI and MR spectroscopy

Background Glioblastoma is relatively uncommon in childhood and maybe difficult to differentiate from other brain tumors such as primitive neuroectodermal tumor, ependymoma, or benign astrocytoma. Objective To describe the characteristic MR features in children with glioblastoma and to evaluate the usefulness of diffusion and perfusion MR imaging and MR spectroscopy in pediatric glioblastoma. Materials and methods MR imaging in 11 children (12 tumors) with biopsy-proven glioblastoma was reviewed retrospectively. In one patient, there was a recurrent glioblastoma. We reviewed CT and MRI imaging for tumor location, density/signal intensity, and enhancement pattern. Routine MR imaging was performed with a 1.5-T scanner. In six patients, diffusion-weighted MR images (DWIs) were obtained with a single-shot spin echo EPI technique with two gradient steps, and apparent diffusion coefficients (ADCs) were calculated. Using the gradient EPI technique, perfusion-weighted MR images (PWIs) were obtained in four patients from the data of dynamic MR images. The maximum relative cerebral blood volume (rCBV) ratio was calculated between the tumor and contralateral white matter in two cases. In three patients, proton MR spectroscopy was performed using a single voxel technique with either STEAM or PRESS sequences. The locations of the tumor were the thalamus and basal ganglia (n=8), deep white matter (n=3), and brain stem (n=1).Results Intratumoral hemorrhage was seen in four tumors. The tumors showed high-signal intensity or DWIs, having a wide range of ADC values of 0.53–1.30 (mean ±SD=1.011±0.29). The maximum rCBV ratios of glioblastoma were 10.2 and 8.5 in two cases. MR spectroscopy showed decreased N-acetylaspartate (NAA) and increased choline in three cases. The MR findings of glioblastoma in children were: a diffusely infiltrative mass with hemorrhage involving the deep cerebral white matter, thalami, and basal ganglia. Conclusion Diffusion/perfusion MR imaging and MR spectroscopy are very helpful in diagnosing glioblastoma, determining the biopsy site, and evaluating tumor recurrence.This paper was presented as a scientific contribution at the 39th Annual Congress of the European Society of Paediatric Radiology, Bergen, Norway, June 2002     

Proton magnetic resonance spectroscopy ((1)H-MRS) of the brain following high-dose methotrexate treatment for childhood cancer

BACKGROUND: To avoid the late sequelae associated with cranial radiation therapy in childhood, intermediate- or high-dose intravenous methotrexate (HDMTX) has found increasing application as a means of preventing the development of overt central nervous system disease in childhood acute leukaemia. However, acute and chronic neurotoxicity has been described following HDMTX therapy, and the long-term intellectual outcome in children treated in this way is inadequately documented. Proton magnetic resonance spectroscopy ((1)H-MRS) of the brain is a noninvasive, quantitative way of assessing aspects of cerebral metabolism, which has not previously been applied to the study of children undergoing central nervous system directed therapy. PROCEDURE: To evaluate the potential role of (1)H-MRS in the investigation of related neurotoxicity, 11 children who had received HDMTX (cumulative dose 6-96 g/m(2)) underwent localised (1)H-MRS, magnetic resonance imaging. Neuropsychological assessments were performed on the children who had more than 1 year of follow-up time since last methotrexate treatment. Control (1)H-MRS studies on 11 adult and 6 young volunteers were undertaken. Eight patients had spectra of adequate quality. Comparisons between (1)H-MRS metabolite ratios and normal controls were made. RESULTS: Patients had a low choline/water ratio compared to controls (P < 0.01). No differences between patient and control NAA/water, Cr/water, Naa/Cr, and Cho/Cr ratios were seen. Overall, 3 patients had abnormal white matter changes on MRI. The mean IQ of the patients (104.1) was in the normal range. CONCLUSIONS: It is postulated that choline depletion in the brains of these patients may reflect subclinical disturbances of myelin metabolism as a result of methotrexate therapy and may represent a possible avenue of treatment in patients with clinical chronic methotrexate-related neurotoxicity.     

Magnetic resonance imaging in juvenile Canavan disease

We present a 2-year-old boy and a 6-year-old girl with mild Canavan disease (CD). Aspartoacylase activity in skin fibroblasts was deficient. Magnetic resonance imaging (MRI) of the brain did not show the prominent leucodystrophy previously reported in CD, but there was a hyperintense signal from the lentiform nuclei and the heads of the caudate nuclei on the T2-weighted MR images. This suggests a specific vulnerability of the corpus striatum in these patients. In the older patient, the white matter became affected at the age of 6 years. Proton magnetic resonance spectroscopy (¹H-MRS) of white matter revealed a normal concentration of N-acetyl-l-aspartate (NAA) and a markedly decreased concentration of choline containing compounds (Cho) in the boy but a normal ratio of NAA to Cho in the girl. We conclude that deficient NAA catabolism affects myelin metabolism. This may present as changes in the striatum and/or as a low concentration of Cho before leucodystrophy appears on MRI.     

A syndrome of irreversible leukoencephalopathy following pediatric allogeneic bone marrow transplantation

BACKGROUND: Despite decreases in overall mortality following bone marrow transplantation (BMT), a number of complications such as neurotoxicity have been described and often associated with immunosuppressive agents. The syndrome of reversible posterior leukoencephalopathy has been described in patients receiving cyclosporin and FK-506. We report here a subset of children who developed a syndrome of previously undescribed irreversible leukoencephalopathy following allogeneic BMT. PATIENTS AND METHODS: Between 1996 and 2002, 138 pediatric patients received an allogeneic BMT at Lucile Salter Packard Children's Hospital at Stanford. Six cases of irreversible leukoencephalopathy were observed. Cases were defined as children who exhibited progressive and continued, severe neurologic deterioration lasting greater than 2 weeks and consistent with non-localizing, central nervous system abnormalities. Medical records and magnetic resonance images (MRIs) were reviewed. RESULTS: Median age of the affected patients at BMT was 7.8 years. All six received cyclosporine, and [corrected] one had elevated drug levels. Encephalopathy occurred at a median of 53 days (range 14-77) following BMT. Symptoms at onset of leukoenceophalopathy included confusion and altered mental status, sluggish pupillary responses, abnormal movements, and seizures. Two patients died during their neurologic decline. Four patients remain alive with persistent encephalopathy. MRI showed abnormalities in all patients including periventricular or subcortical white matter involvement in all, and basal ganglia lesions in three. CONCLUSIONS: We report a syndrome of irreversible neurologic deficits and cerebral white matter abnormalities following allogeneic BMT, yet not associated with elevated cyclosporin levels. A precise mechanism for this syndrome is lacking and warrants further consideration.     

Cerebral metabolite differences in adolescents with low birth weight: assessment with in vivo proton MR spectroscopy

Background Children with very low birth weight (VLBW) have a significantly increased risk of later neurodevelopmental problems, while infants born small for gestational age (SGA) at term are also at some risk of developing neurological impairment.Objective To investigate possible brain metabolite differences in adolescents with VLBW, SGA at term and controls by proton in vivo magnetic resonance spectroscopy (MRS) at 1.5 T.Materials and methods MR spectra were acquired from volumes localized in the left frontal lobe, containing mainly white matter (54 subjects). Peak areas of N-acetyl aspartate (NAA), choline (Cho) and creatine (Cr) were determined, and the peak area ratio of NAA to Cr, total Cho to Cr, or NAA to Cho calculated. Probabilistic neural network (PNN) analysis was performed utilizing the chemical shift region containing resonances from NAA, Cho and Cr as inputs.Results No significant difference in the peak area ratios could be found using the Kruskal-Wallis test. By application of PNN, a correct classification of 52 of the 54 adolescents with a sensitivity and specificity exceeding 93% for all groups was achieved.Conclusion Small, yet systematic, differences in brain metabolite distribution among the groups were confirmed by PNN analysis.     

Lafora disease: Spectroscopy study correlated with neuropsychological findings

PURPOSE: To evaluate the metabolic changes both in grey and white matter in Lafora disease using proton magnetic resonance spectroscopy and to determine the possible correlation with the pattern of cognitive impairment. METHODS: Five patients with Lafora disease and six healthy controls were included in the study. Patients underwent at the same time-point neuropsychological testing and 1[H]MRS, using PRESS sequences (TE=136 and 25 ms) positioned in the frontal and posterior cingulate gyrus cortexes and in the adjacent frontal and parietal white matter. RESULTS: Neuropsychological testing showed in all patients a prevalent involvement of performance abilities--with partial sparing of verbal competences--and of executive functions, suggesting a major involvement of frontal areas. Analysis of 1[H]MRS showed a statistically significant reduction in NAA/mI and NAA/Cr in grey matter of patients compared to controls, more significant in frontal regions. In white matter, a significant reduction of NAA/mI ratio was observed both in the frontal and parietal regions, associated with a reduction of the NAA/Cr only in the frontal white matter. NAA/mI was found to be the most statistically significant altered parameter in all regions studied and the only significantly altered ratio in strong correlation with all sets of neuropsychological parameters. CONCLUSIONS: Our study confirmed the predominant metabolic damage in the frontal cortex, also demonstrating NAA/mI ratio to be the most sensitive parameter to detect metabolic brain changes in Lafora disease; moreover, it evidenced frontal white matter spectroscopic changes. Both spectroscopy values and clinical features of cognitive impairment showed a prevalent frontal impairment.     

Incidence of brain creatine transporter deficiency in males with developmental delay referred for brain magnetic resonance imaging

Several case reports describe children with global developmental delay who have brain creatine deficiency, where the deficiency was due to a lack of creatine transport into the brain or altered creatine synthesis. The purpose of this study was to determine what percentage of males with developmental delay referred for brain magnetic resonance imaging (MRI) at the authors' institution in a 12-month period was found to have brain creatine deficiency due to a defect in the creatine transporter gene. In the authors' facility, single voxel proton magnetic resonance spectroscopy (MRS) is routinely performed on any male child age 2 to 18 years with a history of language and/or developmental delay referred for a brain MRI. Charts for the 12-month time period were retrospectively reviewed. Fourteen subjects met inclusion criteria for global developmental delay. Two of the 14 patients had brain creatine deficiency on MRS. In the remaining 12, other structural and white matter abnormalities were identified. This study suggests that brain creatine deficiency is an important consideration in the differential diagnosis of males with global developmental delay referred for brain MRI; brain MRS should be considered in such cases.     

Cerebral structure and metabolism and long-term outcome in small-for-gestational-age preterm neonates

In the present study, we compared brain development and metabolism of small-for-gestational-age (SGA) and appropriate-for-gestational-age (AGA) infants using proton magnetic resonance spectroscopy ((1)H-MRS). We tested the hypothesis that intrauterine growth retardation caused by placental insufficiency is associated with changes in cerebral metabolism and is followed by an adverse neurodevelopmental outcome at the age of 2 y. Twenty-six AGA and 14 SGA (birth weight

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Regional age dependence of human brain metabolites from infancy to adulthood as detected by quantitative localized proton MRS.

Regional changes of metabolite concentrations during human brain development were assessed by quantitative localized proton magnetic resonance spectroscopy in vivo. Apart from measurements in young healthy adults, the study was based on regional spectra from 97 children who were either healthy or suffered from mental retardation, movement disorders, epilepsies, neoplasm, or vascular malformation. Metabolite quantitation focused on cortical gray and white matter, cerebellum, thalamus, and basal ganglia in six age groups from infancy to adulthood. During infancy and childhood, the concentration of the neuroaxonally located N-acetylasparate increased in gray matter, cerebellum, and thalamus, whereas a constant level was detected in white matter. These findings are in line with regional differences in the formation of synaptic connections during early development and suggest a role of N-acetylaspartate as a marker of functioning neuroaxonal tissue rather than of the mere presence of nerve cells. This view is further supported by high concentrations of taurine in gray matter and cerebellum during infancy, because taurine is also believed to be involved in the process of synapse formation. Remarkably, in basal ganglia both N-acetylaspartate and taurine remain constant at relatively high concentrations. Other metabolite changes during maturation include increases of N-acetylaspartylglutamate, especially in thalamus and white matter, and a decrease of glutamine in white matter. Despite regional differences and some small changes during the first year of life, the concentrations of creatine, phosphocreatine, choline-containing compounds, myoinositol, and glutamate remain constant afterward. The creatine to phosphocreatine concentration ratio yields 2:1 throughout the human brain irrespective of region or age. The observed increase of the proton resonance line-width with age is most pronounced in basal ganglia and corresponds to the age-related and tissue-dependent increase of brain iron.     

Serial 1H-MRS in GM2 gangliosidoses

GM2 gangliosidoses are a group of neuronal storage disorders caused by deficiency in the lysosomal enzyme hexosaminidase A. Clinically, the disease is marked by a relentless encephalopathy. Proton magnetic resonance spectroscopy (1H-MRS) provides in-vivo measurement of various brain metabolites including N-acetyl aspartate+N-acetyl aspartate glutamate (NAA), myo-inositol (mI), choline (Cho) and creatine (Cr). The NAA represents neuronal integrity while elevation in the mI reflects abnormal inflammation and gliosis in the brain tissue. An elevation in the Cho levels suggest cell membrane breakdown and demyelination. We report the clinical and laboratory data in two patients with GM2 gangliosidoses. Serial 1H-MRS evaluations were performed to drive metabolite ratios of NAA/Cr, mI/Cr and Cho/Cr. We acquired the data from four regions of interest (ROI) according to a standard protocol. The results documented a progressive elevation in mI/Cr in all four ROI in patient one and only one ROI (occipital gray matter) in patient 2. We also documented a decline in the NAA/Cr ratios in both cases in most ROI. These results were compared to six age-matched controls and confirmed statistically significant elevation in the mI in our cases. In conclusion, 1H-MRS alterations were suggestive of neuronal loss and inflammation in these patients. 1H-MRS may be a valuable tool in monitoring the disease progress and response to therapy in GM2 gangliosidoses. Elevation in the mI may prove to be more sensitive than the other metabolite alterations.     

Biochemical definition of the mucopolysaccharidoses

The excretion pattern of urinary acid mucopolysaccharides was determined in 72 patients with different clinical types of mucopolysaccharidoses and mucolipidoses. Using a chromatographic fractionation method, characteristic excretion patterns were found in the six classical types of mucopolysaccharidoses. Patients with Hunter's disease excreted relatively more heparansulfate and less dermatansulfate than patients with Hurler's disease. In Sanfilippo's disease the excretion of heparansulfate only was increased. In Morquio's disease abnormal amounts of substances with characteristics of chondroitin-4(6)-sulfate were found in addition to keratansulfate. In one patient with Ullrich-Scheie's disease and six patients with Maroteaux's disease relatively large amounts of substances with characteristics of dermatansulfate were present. There was very little overlap between the excretion patterns of different types of mucopolysaccharidoses. In the types of mucolipidoses investigated, the urinary excretion of acid mucopolysaccharides was normal. The intrafamilial variability in eight pairs of related children was small. Our data suggest that the excretion pattern of urinary acid mucopolysaccharides, as determined by the Dowex Column Chromatography Method, is a valuable aid in the definition of the mucopolysaccharidoses.Supported by Grants No. WI 80 of the Deutsche Forschungsgemeinschaft.     

In vivo proton magnetic resonance spectroscopy assessment for muscle metabolism in neuromuscular diseases

Muscle metabolites were obtained by in vivo proton magnetic resonance spectroscopy of 3 patients with Duchenne muscular dystrophy (DMD), 6 patients with spinal muscular atrophy (SMA), and 10 normal volunteers. Patients with DMD and SMA had lower trimethyl amide (TMA)/water and TMA/total creatine (tCr) ratios but normal tCr/water ratios.     

Cardiovascular changes in children with mucopolysaccharide storage diseases and related disorders – clinical and echocardiographic findings in 64 patients

Cardiovascular abnormalities were evaluated in 64 children aged between 1 year 9 months and 25 years with mucopolysaccharidoses (MPS) and related disorders. A heart murmur was heard in 18 patients, but in only 6 was it characteristic for specific valvular lesions. Echocardiography was performed in 63 children. In one girl cardiac lesions were diagnosed on autopsy. In 46 patients (72%), valvular lesions and/or different types of cardiomyopathy were detected. There were no characteristic changes for different types of MPS. In the majority of children in whom dermatan sulphate accumulated, cardiac involvement was the most frequent (88%) and severe. The most common lesion, regardless of MPS type, was thickening of the mitral valve (66%), with regurgitation or stenosis in 28 (44%). Aortic valve thickening was detected in 17 patients (27%), asymmetric septal hypertrophy or hypertrophic cardiomyopathy in 18, congestive cardiomyopathy in 1 and endocardial thickening in 13 patients. Cardiac involvement was less frequent in children with Sanfilippo disease. Two or more echocardiographic examinations were performed in 23 patients. In 19 of them (83%) cardiac changes were more severe during the second examination. One 7-year-old boy with Hunter disease underwent successful mitral valve replacement. Conclusions Cardiac involvement is present in most patients with MPS although there are few clinical signs and symptoms. The most common and severe changes are in Hurler, Hunter, Maroteaux-Lamy and I-cell disease, rarely in Sanfilippo disease. Mitral valve deformation is most frequent in all patients. The cardiac lesions are progressive. Received: 15 March 1997 / Accepted: 20 January 1998