Three adolescents with Lhermitte-Duclos disease

Lhermitte-Duclos disease (LDD) is a rare, benign cerebellar disorder, characterized by replacement of granular cells and Purkinje cells by an overgrowth of cerebellar ganglion cells. LDD can be associated with Cowden’s syndrome (CS). We studied three adolescent LDD patients, including two with CS. MRI revealed the typical tiger-stripe pattern in all patients. CS was diagnosed on the basis of secondary mucocutaneous lesions and a PTEN/MMAC1 gene mutation. Adolescent-onset LDD appears to have the same phenotype and genotype as adult-onset LDD. Total resection of the lesion is recommended as an initial management strategy. We strongly recommend that patients with LDD undergo genetic screening to find out as early as possible whether CS has developed.     

Morphological and functional imaging studies on the diagnosis and progression of Parkinson's disease

This paper reviews the relative abilities of magnetic resonance imaging (MRI), positron emission tomography (PET), single photon emission tomography (SPECT), and proton magnetic resonance spectroscopy (MRS) to detect Parkinson's disease and monitor its progression. Currently, the main role of MRI lies in its ability to discriminate atypical syndromes from Parkinson's disease; however, new volumetric approaches may soon allow progression of nigral degeneration to be followed. Proton MRS can also detect reduced levels of putamen N-acetyl aspartate (NAA) in many patients with atypical parkinsonian syndromes. PET and SPECT are both sensitive means of detecting the presence of impaired dopamine terminal function in the striatum and following its progression. PET currently has the greater spatial resolution and provides the added advantages that it also allows extra-striatal dopaminergic function to be monitored.     

Cowden disease with Lhermitte-Duclos disease: case report

BACKGROUND: We report a case and review the recent literature describing 36 patients with both Lhermitte-Duclos disease (LDD) and Cowden disease (CD). Lhermitte-Duclos disease, or dysplastic gangliocytoma, is a benign hamartomatous condition involving the cerebellum. The presenting symptoms are usually headaches, gait ataxia, and symptoms of lower cranial nerve involvement. Cowden disease is a rare autosomal dominant disease that usually presents with multiple mucocutaneous lesions. Patients with CD are prone to multiple systemic malignancies, the most common of which is breast cancer. Recent studies have demonstrated an association between LDD and CD. METHODS: A 44-year-old woman with a previous history of breast cancer, multiple benign skin lesions, Hashimoto's thyroiditis, and chronic headaches presented with exacerbation of her headaches during the previous year. Magnetic resonance imaging of the brain revealed a right cerebellar nonenhancing mass and an acquired tonsillar herniation. RESULTS: The patient underwent resection of the right cerebellar mass, posterior fossa decompression, C1 and C2 laminectomies, and a duraplasty. Pathologic examination confirmed LDD. The patient recovered well after surgery, with immediate improvement of her headaches. CONCLUSIONS: The association between LDD and CD has been under-recognized and under-reported. Recognition of this association has direct clinical relevance, because diligent monitoring of individuals with LDD and CD may lead to the early detection of systemic malignancies.     

Current status of functional MR imaging, perfusion-weighted imaging, and diffusion-tensor imaging in Alzheimer's disease diagnosis and research

Advanced MR techniques, such as functional MR imaging, perfusion-weighted imaging, and diffusion-tensor imaging, offer the capability of detecting early functional, hemodynamic, and microstructural alterations in Alzheimer's disease before gross anatomic alterations. Most studies of these emerging technologies are at the exploratory stage, with the purpose of increasing understanding of the underlying disease process and defining cross-sectional differences across various subject populations. Assessment of the diagnostic efficacy of these technologies in detecting early Alzheimer's disease in its preclinical and prodromal stages is ongoing.     

Lhermitte-Duclos disease associated with Cowden syndrome.

Lhermitte-Duclos disease or dysplastic gangliocytoma of the cerebellum, is a rare cerebellar lesion, which can cause mass effects in the posterior fossa. It may occur sporadically, or in association with Cowden syndrome. Cowden syndrome or multiple hamartoma-neoplasia syndrome, is an uncommon autosomal dominant condition characterized by mucocutaneous lesions and systemic malignancies. We report two patients with Lhermitte-Duclos disease and associated Cowden syndrome. The clinical, radiological and histopathological features and management strategies of this rare disease complex are discussed.     

Intramedullary ependymoma associated with Lhermitte-Duclos disease and Cowden syndrome

The authors describe the case of a 45-year-old man with progressive gait ataxia and sensorimotor deficits of the upper and lower extremities. The patient had been diagnosed earlier with Lhermitte-Duclos disease (LDD) in the left cerebellar hemisphere and Cowden syndrome (CS). MR imaging studies revealed an intraspinal tumor at C6-C7. Microsurgical gross total resection of the tumor was achieved. Histolopathological examination revealed an intramedullary ependymoma. Postoperatively, neurological deficits gradually improved. This is the first reported case of ependymoma in a patient with LDD and CD. Coexistence of an intraspinal ependymoma with cerebellar LDD and CS appears to be rare, but can lead to treatment failure if missed.     

Motion detection and correction in functional MR imaging

Subject motion present during the time course of functional activation studies is a pervasive problem in mapping the spatial and temporal characteristics of brain activity. In functional MRI (fMRI) studies, the observed signal changes are small. Therefore, it is crucial to reduce the effect of subject motion during the acquisition of image data in order to differentiate true brain activation from artifactual signal changes due to subject motion. We have adapted a technique for automatic motion detection and correction which is based on the ratio-variance minimization algorithm to the fMRI subject motion problem. This method was used for retrospective correction of subject motion in the acquired data and resulted in improved functional maps. In this paper we have designed and applied a series of tests to evaluate the performance of this technique which span the classes of image characteristics common to fMRI. These areas include tests of the accuracy and range of motion as well as measurement of the effect of image signal to noise ratio, focal activation, image resolution, and image coverage on the motion detection system. Also, we have evaluated the amount of residual motion remaining after motion correction, and the ability of this technique to reduce the motion-induced artifacts and restore regions of activation lost due to subject motion. In summary, this method performed well in the range of image characteristics common for fMRI experiments, reducing motion to under 0.5 mm, and removed significant motion-induced artifacts while restoring true regions of activation. Motion correction is expected to become a routine requirement in the analysis of fMRI experiments. © 1995 Wiley-Liss, Inc.     

Lhermitte-Duclos disease and Cowden disease: a single phakomatosis

Two unrelated patients with macrocephaly, seizures, and mild cerebellar signs had a dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease). Both also had autosomal dominant Cowden disease as evidenced by facial, oral, and acral papules. In the two families, 9 sibs demonstrated the mucocutaneous lesions, thyroid disease, breast tumors, and ovarian tumors compatible with the diagnosis of Cowden disease. Some of the sibs also showed various degrees of neurological signs such as macrocephaly, mental retardation, seizures, tremor, and dysdiadochokinesia. Magnetic resonance imaging scans of sibs of one family demonstrated megalencephaly and other mild abnormalities. The occurrence of these two rare disorders in single patients is more than a coincidence, and the clinical findings in the combined condition establishes it as a new phakomatosis.     

Immunohistochemistry and proliferative activity in Lhermitte-Duclos disease

Summary We have evaluated a recurrence of Lhermitte-Duclos disease by immunohistochemistry for Purkinje cell markers and proliferative activity (proliferating cell nuclear antigen), by electron microscopy and for DNA ploidy (image analysis). While most of the abnormal neurons in the lesion appear to be derived from granule cells, several Purkinje cell specific polyclonal and monoclonal antibodies, including L7, PEP 19 and calbindin, labeled a minor subpopulation. Staining with monoclonal antibodies to proliferating cell nuclear antigen and measuring cell DNA index and ploidy with a cell image analyzer revealed no proliferative activity. Electron microscopy findings were similar to those previously reported. In spite of its recurrence, our findings support the notion that Lhermitte-Duclos disease is malformative, not neoplastic, and that the characteristic neurons are derived predominantly but not exclusively from a non-Purkinje cell source, probably the granule cell.     

Electroencephalography-correlated functional MR imaging studies of epileptic activity

EEG-fMRI is capable of providing novel localizing information in a substantial proportion of patients with frequent epileptiform discharges, even at 1.5T, suggesting a potential clinical role. Increasing availability of equipment capable of providing good-quality intra-MR imaging EEG with relative ease should ensure a more widespread application of the technique in neurology and neuroscience. Early findings in epilepsy have raised a number of interesting issues related to the localization of the activations and the time course of the event-related response that require further investigation. These investigations will benefit from substantial increases in sensitivity resulting from recent and forthcoming technical developments.Validation of the findings will require comparison with invasive and postsurgical findings and further correlations with other measures of brain activity,which should also lead to an improved understanding of the underlying phenomena. To facilitate comparison of findings, improved reporting standards are needed-namely, illustration of activation maps using the glass-brain-more consistent threshold selection,and the listing of all activation clusters, including their volumes, maximum (or minimum) z scores, and peak signal change.     

The clinical applications of functional MR imaging.

Functional MR imaging, similar to positron-emission tomography, shows the regions in which cerebral blood flow changes as neurons are active in the performance of cognitive tasks. Blood flow increases (activation) exceed that needed to supply oxygen for the increased metabolic needs for the increased neuronal activity. Therefore, in regions with activation, the deoxyhemoglobin concentration in the capillary blood decreases below levels found in the brain where neurons are not active.     

A case report of Lhermitte-Duclos disease with systematic AVMs]

We report a case of Lhermitte-Duclos disease (LDD) with huge AVMs of left extremities. The patient is a 46-year-old woman, who was identified heart failure due to AVMs at 13 years old and underwent amputation of left arm and several embolizations for AVM of left leg. Following a loss of consciousness, she was admitted to our hospital at 46 years old. CT scan showed a low-density area in the vermis of cerebellum. MR imaging showed a tumor with characteristic parallel linear striation. She was treated with partial resection of tumor. Pathological findings were dysplastic gangliocytoma. She was diagnosed LDD by MR imaging and pathological findings. Some reports describe an association between LDD and Cowden disease. On the other hand, there are reports of an association between Cowden disease and AVM. However, to our knowledge, there is no report of an association between LDD and AVM. Although this case didn't be revealed an association with Cowden disease, we believe that this case is a very interesting one henceforth suggesting the association between LDD, Cowden disease, and AVM.     

Anatomy and pathology of the eye: role of MR imaging and CT

Since the development of CT and MR imaging, significant progress in ophthalmic imaging has been made. As the technology advanced and MR imaging units improved their ability in terms of spatial resolution, the role of MR imaging in ophthalmic imaging has increased accordingly. This article considers the role of MR and CT imaging in the diagnosis of selected pathologies of the eye.     

Pelizaeus-Merzbacher disease: diffusion MR imaging and proton MR spectroscopy findings

A 5-Year-old boy is reported with genetically confirmed Pelizaeus-Merzbacher disease. On chemical-shift spectroscopic imaging choline (Cho) peaks were prominently decreased in the white matter resulting in markedly high NAA/Cho ratios, and low Cho/Cr ratios, compared to five control cases. Low Cho levels could be indicative of the dysmyelinating disorder in the disease. On b=1000 s/mm(2) images of diffusion MRI, a tigroid pattern was evident, and there was no apparent signal abnormality. However, on ADC maps high signal and high ADC values were evident in the white matter ranging from 1.16 to 1.52 X 10(-3) mm(2)/s, compared to the ADC values of nine control cases, consistent with some disintegration of the white matter secondary to lack of myelination. On the other hand, the ADC values of the cortex were normal (0.79-0.95 X 10(- 3) mm(2)/s). These findings on spectroscopy and diffusion MRI likely represented deficient myelination in the disease.     

Postural and gait symptoms in de novo Parkinson's disease patients correlate with cholinergic white matter pathology

IntroductionThe postural instability gait difficulty motor subtype of patients with Parkinson's disease (PIGD-PD) has been associated with more severe cognitive pathology and a higher risk on dementia compared to the tremor-dominant subtype (TD-PD). Here, we investigated whether the microstructural integrity of the cholinergic projections from the nucleus basalis of Meynert (NBM) was different between these clinical subtypes.MethodsDiffusion-weighted imaging data of 98 newly-diagnosed unmedicated PD patients (44 TD-PD and 54 PIGD-PD subjects) and 10 healthy controls, were analysed using diffusion tensor imaging, focusing on the white matter tracts associated with cholinergic projections from the NBM (NBM-WM) as the tract-of-interest. Quantitative tract-based and voxel-based analyses were performed using FA and MD as the estimates of white matter integrity.ResultsVoxel-based analyses indicated significantly lower FA in the frontal part of the medial and lateral NBM-WM tract of both hemispheres of PIGD-PD compared to TD-PD. Relative to healthy control, several clusters with significantly lower FA were observed in the frontolateral NBM-WM tract of both disease groups. Furthermore, significant correlations between the severity of the axial and gait impairment and NBM-WM FA and MD were found, which were partially mediated by NBM-WM state on subjects’ attentional performance.ConclusionsThe PIGD-PD subtype shows a loss of microstructural integrity of the NBM-WM tract, which suggests that a loss of cholinergic projections in this PD subtype already presents in de novo PD patients.     

The brachial plexus: normal anatomy, pathology, and MR imaging

The brachial plexus is the most technically and anatomically challenging area of the peripheral nervous system for diagnostic imaging. Marked improvements in spatial and contrast resolution of plexus images have resulted from the use of phased-array technology and newer MR pulse sequence designs. This article presents case material incorporating these improvements and discusses the primary factors that continue to limit MR image quality, such as inhomogenous fat suppression, motion artifacts, and small vessels that mimic or obscure plexus components, and potential solutions and imaging alternatives. Brachial plexus anatomy and its appearance on multiplanar MR images are reviewed. The morphologic features and MR signal characteristics that have been found useful in distinguishing between normal and abnormal plexus components,and in detecting neuropathic lesions, are addressed in the context of clinical indications for plexus imaging as follows: mass involving the plexus, traumatic injury, entrapment syndrome, posttreatment evaluation, and miscellaneous conditions.