Quantitative analysis of gray- and white-matter volumes and glucose metabolism in Sturge-Weber syndrome

Rasmussen syndrome in a tropical environment: a study of six (6) observations

Background

In sub-Saharan Africa, encephalitis of various etiologies is a major public health problem and Rasmussen syndrome is rarely diagnosed due to under-medicalization. The objective of this study is to describe the clinical and neuroradiological forms, especially since this affection is little known in sub-Saharan Africa as evidenced by the scarcity of publications.

Results

A retrospective, descriptive and analytical study of six (6) cases of Rasmussen syndrome, shows that it is an unrecognized disease in Africa. Men were more represented with a frequency of 67% with a young age. The clinical picture dominated by 100% seizures, mental deterioration and hemiparesis. The etiology is still questionable, probably autoimmune in our study.

Conclusion

Rasmussen syndrome accounts for 3% in 219 patients hospitalized for epileptic conditions. This study shows a clinical profile dominated by recurrent epileptic seizures refractory to the drugs Phenobarbital, Valproic Acid and Carbamazepine, the only antiepileptics available in the country. These results are valid for therapeutic and prognostic discussion.

Quantitative Assessment of Brain Networks in Children With Sturge-Weber Syndrome Using Resting State Functional Magnetic Resonance Imaging (MRI)

In this study, we examined whether topologic network analysis, using resting state functional magnetic resonance imaging (MRI), can detect abnormalities of functional brain connectivity in children with unilateral brain injury due to Sturge-Weber syndrome. Three children with Sturge-Weber syndrome (ages 1, 3, and 10 years) underwent structural and resting state functional MRI, glucose metabolism positron emission tomography (PET), and neurocognitive evaluation. Eight different resting state networks were compared between the affected and unaffected hemispheres by quantitatively accessing communication efficiency measures. Significantly reduced efficiency values were found in all 3 patients. Visual network deficiency was present in both children with a visual field defect; frontal network abnormalities were associated with fine motor impairment. Location of network abnormalities corresponded to and, in some cases, extended beyond structural MRI and glucose PET abnormalities. The presented approach can detect early functional abnormalities of specific brain networks in children with Sturge-Weber syndrome.

Localization of function-specific segments of the primary motor pathway in children with Sturge-Weber syndrome: a multimodal imaging analysis

PURPOSE

To explore whether diffusion-weighted imaging (DWI) can localize specific segments of primary motor areas in children with Sturge-Weber syndrome (SWS), this study investigated the corticospinal tract (CST) between precentral gyrus (PCG) and posterior limb of internal capsule (PIC).

MATERIALS AND METHODS

DWI was performed on 32 healthy children and seven children with unilateral SWS affecting the sensorimotor area variably. A hierarchical dendrogram was applied to find PCG-segments uniquely connected to PIC-segments. The resulting PCG-clusters were used to image primary motor pathways in DWI and find metabolic abnormalities of primary motor areas in positron emission tomography (PET) scans.

RESULTS

In healthy children, five PCG-clusters were found to have unique CST courses, corresponding to CST segments of mouth/lip, fingers, and leg/ankle primary motor areas determined by functional magnetic resonance imaging (fMRI). In children with SWS, reduced streamlines in these PCG clusters were highly correlated with glucose-hypometabolism on PET (R(2) = 0.2312, P = 0.0032). Impaired CST segment corresponding to finger movements correlated with severity of hand motor deficit.

CONCLUSION

The presented method can detect impaired CST segments corresponding to specific motor functions in young children who cannot cooperate for fMRI. This approach can be clinically useful for a noninvasive presurgical evaluation of cortical motor areas in such children.

Clinical correlates of white matter blood flow perfusion changes in Sturge-Weber syndrome: a dynamic MR perfusion-weighted imaging study

BACKGROUND AND PURPOSE

Low brain tissue perfusion due to abnormal venous drainage is thought to be a central mechanism of brain damage in SWS. Here, HR-PWI was used to quantify WM perfusion abnormalities and to correlate these with brain atrophy and clinical variables.

MATERIALS AND METHODS

Fourteen children (age range, 0.8-10.0 years) with unilateral SWS underwent MR imaging examinations, including HR-PWI. rCBV, rCBF, and MTT in the affected WM and in contralateral homotopic WM were measured. AI for each perfusion parameter was correlated with age, brain atrophy, and motor and seizure variables as well as IQ.

RESULTS

Increased perfusion was seen in the affected hemisphere in 5 children and decreased perfusion in 9 children. Brain atrophy was more severe in the low-perfusion group (P = .01) and was related to both CBF-AI and CBV-AI (r = -0.69, P = .007; r = -0.64, P = .014, respectively). Older children had lower CBV values on the affected side (r = -0.62, P = .02). Longer duration of epilepsy was related to lower CBF (more negative CBF-AI, r = -0.58, P = .03) and low CBV (r = -0.55, P = .04) on the affected side. Lower perfusion was associated with more frequent seizures (rCBF-AI: r = -0.56, P = .04; rCBV-AI: r = -0.63, P = .02).

CONCLUSIONS

Increased perfusion in the affected cerebral WM may indicate an early stage of SWS without severe brain atrophy. Decreased perfusion is associated with frequent seizures, long duration of epilepsy, and brain atrophy.

Transient focal cortical increase of interictal glucose metabolism in Sturge-Weber syndrome: implications for epileptogenesis

PURPOSE

To investigate clinical correlates and longitudinal course of interictal focal cortical glucose hypermetabolism in children with Sturge-Weber syndrome (SWS).

METHODS

Fluorodeoxyglucose positron emission tomography (FDG-PET) scans of 60 children (age range 3 months to 15.2 years) with Sturge-Weber syndrome and epilepsy were assessed prospectively and serially for focal hypo- or hypermetabolism. Thirty-two patients had two or more consecutive PET scans. Age, seizure variables, and the occurrence of epilepsy surgery were compared between patients with and without focal hypermetabolism. The severity of focal hypermetabolism was also assessed and correlated with seizure variables.

KEY FINDINGS

Interictal cortical glucose hypermetabolism, ipsilateral to the angioma, was seen in nine patients, with the most common location in the frontal lobe. Age was lower in patients with hypermetabolism than in those without (p=0.022). In addition, time difference between the onset of first seizure and the first PET scan was much shorter in children with increased glucose metabolism than in those without (mean: 1.0 vs. 3.6 years; p=0.019). Increased metabolism was transient and switched to hypometabolism in all five children where follow-up scans were available. Focal glucose hypermetabolism occurred in 28% of children younger than the age of 2 years. Children with transient hypermetabolism had a higher rate of subsequent epilepsy surgery as compared to those without hypermetabolism (p=0.039).

SIGNIFICANCE

Interictal glucose hypermetabolism in young children with SWS is most often seen within a short time before or after the onset of first clinical seizures, that is, the presumed period of epileptogenesis. Increased glucose metabolism detected by PET predicts future demise of the affected cortex based on a progressive loss of metabolism and may be an imaging marker of the most malignant cases of intractable epilepsy requiring surgery in SWS.

Focal white matter abnormalities related to neurocognitive dysfunction: an objective diffusion tensor imaging study of children with Sturge-Weber syndrome

White matter (WM) loss is associated with cognitive impairment in Sturge-Weber syndrome (SWS). In this study, we evaluated if cognitive and fine motor abnormalities are associated with impaired microstructural integrity in specific WM regions in SWS. Fifteen children with unilateral SWS (age: 3-12.4 y) and 11 controls (age: 6-12.8 y) underwent diffusion tensor imaging. Tract-based spatial statistics was used for objective comparisons of WM fractional anisotropy (FA) and mean diffusivity (MD) between the two groups. In the SWS group, WM FA and MD values were correlated with intelligence quotient (IQ) and fine motor scores, with age as a co-variate. Bilateral, multilobar WM areas showed decreased FA, whereas significant MD increases were confined to small ipsilateral posterior regions in SWS children. IQ in the SWS group (range: 47-128) was positively correlated with FA in the ipsilateral prefrontal WM and inversely associated with MD in the ipsilateral posterior parietal WM. A negative correlation between fine motor function and MD was found in ipsilateral frontal WM encompassing motor pathways. Microstructural WM abnormalities occur not only ipsilateral but also contralateral to the angioma in unilateral SWS. Nevertheless, cognitive and fine motor functions are related to diffusion abnormalities in specific ipsilateral, mostly frontal, WM regions.

Cerebral perfusion abnormalities in children with Sturge-Weber syndrome shown by dynamic contrast bolus magnetic resonance perfusion imaging

OBJECTIVE

Sturge-Weber syndrome is characterized by leptomeningeal angiomatosis and a facial naevus that is usually unilateral. Magnetic resonance imaging is the cornerstone of confirming the disease and judging the extent of the abnormalities. It has been shown, however, that brain perfusion abnormalities on nuclear medicine imaging often are more extensive than the abnormal leptomeningeal enhancement on magnetic resonance. In this article, we assess the utility of magnetic resonance perfusion in demonstrating perfusion abnormalities in pediatric cases of Sturge-Weber syndrome.

METHODS

Magnetic resonance perfusion studies were performed on 7 consecutive children who presented to our department with clinically suspected Sturge-Weber syndrome. The extent of time to peak abnormality on dynamic gadolinium bolus magnetic resonance perfusion imaging was compared with the extent of leptomeningeal enhancement and the presence of venous abnormalities.

RESULTS

Good magnetic resonance perfusion data were obtained in all 7 cases. Perfusion abnormalities were closely anatomically related to meningeal enhancement on postcontrast T1-weighted imaging. However, perfusion abnormalities were found consistently in the vicinity of developmental venous anomalies that were present in 4 of 7 cases. In 1 child, there was a perfusion deficit in the cerebellar lobe contralateral to the leptomeningeal angiomatosis, consistent with crossed cerebellar diaschisis.

CONCLUSIONS

Magnetic resonance perfusion is a sensitive indicator of perfusion abnormalities in Sturge-Weber syndrome and can be performed easily at the same time as the diagnostic scan. Magnetic resonance perfusion imaging therefore is useful in the assessment of this disease. This approach has the extra advantage of correlating the perfusion abnormalities with the high-resolution imaging that is provided from magnetic resonance imaging.

Sturge-Weber syndrome: A case study

Sturge-Weber syndrome (SWS) is a rare, sporadic, progressive, congenital syndrome. In its complete trisymptomatic form, SWS is physically characterized by port-wine stains over the trigeminal area, leptomeningeal angiomas usually over the parieto-occipital region, and eye abnormalities. Clinical manifestation for infants with SWS depends on the affected organs, but can include seizures, mental retardation, and glaucoma. This article begins with a case presentation of an infant with SWS and then presents the etiology, embryology, pathophysiology, clinical presentation, management, and prognosis of SWS.

Quantitative analysis of cerebral cortical atrophy and correlation with clinical severity in unilateral Sturge-Weber syndrome

Sturge-Weber syndrome is a neurocutaneous disorder with vascular malformations of the skin, brain, and eye. The objective of this study was to determine whether cortical atrophy in patients with Sturge-Weber syndrome correlates with clinical severity. Eighteen subjects (age 4 months-35 years) with unilateral Sturge-Weber syndrome received a neurologic examination and submitted previous magnetic resonance imaging (MRI) films. A blinded investigator assigned clinical severity scores based on seizures, hemiparesis, visual field cut, and cognitive impairments. Computer-aided analysis of MRIs produced laterality scores for cortical volume asymmetry. A significant relationship existed between clinical severity and laterality scores (Spearman's rho = -0.804; P < .001). Laterality scores also correlated well with hemiparesis subscores and weakly with cognitive impairment subscores (Kendall's tau b; P < .05). Using this simple, computer-aided analysis, cortical volume asymmetry correlated with clinical status. This method offers the advantages of relative simplicity, objectivity, and wide applicability to films from outside institutions, as would be encountered in clinical practice.

Neurocutaneous syndromes: behavioral features

Neurocutaneous syndromes are disorders characterized by a neurological abnormality and cutaneous manifestations. Three of the more common neurocutaneous syndromes are Sturge-Weber syndrome, tuberous sclerosis, and neurofibromatosis. This review focuses on the cognitive and behavioral features of these syndromes.

Early diagnosis of cerebral involvement in Sturge-Weber syndrome using high-resolution BOLD MR venography

Sturge-Weber syndrome (SWS) is a congenital disorder characterized by a vascular birthmark and neurological abnormalities. Typical imaging findings using MRI or CT are superficial cerebral calcification, atrophy and leptomeningeal enhancement. We present a neonate diagnosed with SWS because of a port-wine stain. In the absence of neurological symptoms the first MRI was performed when he was 4 months old, and follow-up MRI studies were performed after his first seizure at the age of 12 months. MRI was performed using standard sequences before and after administration of IV gadolinium. A high-resolution T2*-weighted, rf-spoiled 3D gradient-echo sequence with first-order flow compensation in all three directions was used for additional venographic imaging [blood-oxygen-level-dependent (BOLD) venography]. The initial conventional MRI sequences did not demonstrate any abnormality, but BOLD venography identified leptomeningeal internal veins. Follow-up MRI after the first onset of seizures demonstrated strong leptomeningeal enhancement, while BOLD venography revealed pathological medullary and subependymal veins as well as deep venous structures. At this time there were the first signs of atrophy and CT showed marginal calcifications. This report demonstrates that high-resolution BOLD MR venography allows early diagnosis of venous anomalies in SWS, making early therapeutic intervention possible.

Magnetic resonance imaging reveals neuronal degeneration in the brainstem of the superoxide dismutase 1G93A G1H transgenic mouse model of amyotrophic lateral sclerosis

Magnetic resonance imaging (MRI) is becoming the preferred neuroimaging modality for the diagnosis of human amyotrophic lateral sclerosis (ALS). A useful animal model of ALS is the superoxide dismutase 1G93A G1H transgenic mouse, which shows many of the clinico-pathological features of the human condition. We have employed a 4.7-Tesla MRI instrument to determine whether a noninvasive imaging approach can reveal pathological changes in the nervous system of this animal model. Our T2-weighted MRI revealed consistent changes in brain and brainstem of these mice. Hyperintensities, indicative of neuropathology, were observed in several areas including the nucleus ambiguus, facial nucleus, trigeminal motor nucleus, rostroventrolateral reticular nucleus, lateral paragigantocellular nucleus and the substantia nigra. Histology analysis including neuronal counts of the imaged brains confirmed the T2-weighted MRI findings. Enlarged ventricles and hypointense striations, indicative of global atrophy, were also observed in the brain and cerebellum. This atrophy was confirmed by fresh brain weight data. The extensive global degeneration involving multiple structures suggests a multisystem disease that is similar to human ALS.

The role of positron emission tomography with [18F]fluorodeoxyglucose in the evaluation of the epilepsies

Cerebral glucose metabolic mapping using positron emission tomography (PET) and 2-[18F]fluoro-2-deoxyglucose (FDG) has been extensively studied in the epilepsies. Regions of interictal glucose hypometabolism are highly associated with cerebral sites of seizure generation-propagation in focal epilepsies. The volume of reduced glucose metabolism is often widespread and even bilateral in focal epilepsies, although ictal onset zones typically are located at the sites of most severe hypometabolism within a larger volume of hypometabolism.