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Doris D M Lin

Publications and source records attributed to Doris D M Lin.

11 recordsLinked to original sources
PubMed2006

Dynamic MR perfusion and proton MR spectroscopic imaging in Sturge-Weber syndrome: correlation with neurological symptoms.

PURPOSE: To investigate physiological alterations in Sturge-Weber syndrome (SWS) using MR perfusion imaging (PWI) and proton spectroscopic imaging (MRSI), and their association with neurological status. MATERIALS AND METHODS: Six consecutive patients with a clinically established diagnosis of SWS underwent MRI using a 1.5 Tesla scanner. The protocol consisted of conventional anatomic scans, dynamic PWI, and multislice MRSI. A pediatric neurologist evaluated the neurological scores, and the imaging results were correlated with neurological scores using nonparametric correlation analysis. RESULTS: Two patients had classic neuroimaging findings of unilateral cerebral atrophy with corresponding leptomeningeal enhancement and hypoperfusion (prolonged mean transit time). Two patients had bilateral disease, and two had normal symmetric perfusion. Among clinical measures, the highest correlation was between hemiparesis index and hypoperfused tissue volume (Spearman's correlation coefficient, rho = 0.943, P < 0.05). There was also a trend of correlation, although not statistically significant (P = 0.06), between the hemiparesis score and the NAA/Cr ratio in the mid to posterior centrum semiovale, lateral gray matter (GM), and splenium. CONCLUSION: In SWS, PWI indicates cerebral hypoperfusion predominantly due to impaired venous drainage, with only the most severely affected regions in some patients also showing arterial perfusion deficiency. The extent and severity of the perfusion abnormality and neuronal loss/dysfunction reflect the severity of neurological symptoms and disability, and the highest correlation is found with the degree of hemiparesis. These parameters may be useful as quantitative measures of disease burden; however, further studies in larger number of patients (and with a more homogeneous age range) are required to confirm the preliminary findings reported here.

Adolescent↗
PubMed2006

Neuroimaging of phakomatoses.

The phakomatoses are congenital disorders manifesting with central nervous system and cutaneous abnormalities. The structures predominantly affected are those of ectodermal origin, including the skin, nervous system, and eyes. The 4 most common phakomatoses are neurofibromatosis (types 1 and 2), tuberous sclerosis, Sturge-Weber disease, and von Hippel-Lindau disease. Imaging of the brain and spine in these disorders plays an important role in diagnosis, as well as determining the extent of involvement and guiding surgical interventions. This article reviews the application of x-ray computed tomography and magnetic resonance imaging to these disorders, as well as that of newer, "functional" imaging techniques such as positron emission tomography, magnetic resonance perfusion imaging, and spectroscopy.

Central Nervous System↗
PubMed2005

The effect of higher order RNA processes on changing patterns of protein domain selection: a developmentally regulated transcriptome of type 1 inositol 1,4,5-trisphosphate receptors.

The domain structure of proteins synthesized from a single gene can be remodeled during tissue development by activities at the RNA level of gene expression. The impact of higher order RNA processing on changing patterns of protein domain selection may be explored by systematically profiling single-gene transcriptomes. itpr1 is one of three mammalian genes encoding receptors for the second messenger inositol 1,4,5-trisphosphate (InsP3). Some phenotypic variations of InsP3 receptors have been attributed to hetero-oligomers of subunit isoforms from itpr1, itpr2, and itpr3. However, itpr1 itself is subject to alternative RNA splicing, with 7 sites of transcript variation, 6 within the ORF. We have identified 17 itpr1 subunit species expressed in mammalian brain in ensembles that change with tissue differentiation. Statistical analyses of populations comprising >1,300 full-length clones suggest that subunit variation arises from a variably biased stochastic splicing mechanism. Surprisingly, the protein domains of this highly allosteric receptor appear to be assembled in a partially randomized way, yielding stochastic arrays of subunit species that form tetrameric complexes in single cells. Nevertheless, functional expression studies of selected subunits confirm that splicing regulation is connected to phenotypic variation. The potential for itpr1 subunits to form hetero-tetramers in single cells suggests the expression of a developmentally regulated continuum of molecular forms that could display diverse properties, including incremental sensitivities to agonist activation and varying patterns of Ca2+ mobilization. These studies illuminate the extent to which itpr1 molecular phenotype is induced by higher order RNA processing.

3' Untranslated Regions↗
PubMed2005

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.

Adolescent↗
PubMed2004

Mutations in a human ROBO gene disrupt hindbrain axon pathway crossing and morphogenesis.

The mechanisms controlling axon guidance are of fundamental importance in understanding brain development. Growing corticospinal and somatosensory axons cross the midline in the medulla to reach their targets and thus form the basis of contralateral motor control and sensory input. The motor and sensory projections appeared uncrossed in patients with horizontal gaze palsy with progressive scoliosis (HGPPS). In patients affected with HGPPS, we identified mutations in the ROBO3 gene, which shares homology with roundabout genes important in axon guidance in developing Drosophila, zebrafish, and mouse. Like its murine homolog Rig1/Robo3, but unlike other Robo proteins, ROBO3 is required for hindbrain axon midline crossing.

Adult↗
PubMed2003

Diffusion-tensor MR imaging in children with developmental delay: preliminary findings.

PURPOSE: To determine whether diffusion-tensor magnetic resonance (MR) imaging can depict abnormalities in patients with a diagnosis of developmental delay but structurally normal brain MR imaging results. MATERIALS AND METHODS: Twenty pediatric patients who received a diagnosis of developmental delay underwent brain MR examinations, including diffusion-tensor MR imaging. The MR findings in these patients were compared with those in 10 age-matched neurodevelopmentally healthy children. Diffusion constant (Dav) and anisotropy were measured bilaterally in regions of interest in the centrum semiovale, corona radiata, internal capsule, corpus callosum, and subcortical white matter of the frontal and parieto-occipital lobes. By using a one-tailed Student t test in the positive direction for Dav and in the negative direction for anisotropy and P <.05 to indicate a significant difference, the Dav and anisotropy values for children with developmental delay were compared with those for children who were neurodevelopmentally healthy. RESULTS: The children with developmental delay had significant increases in Dav in all measured structures (P, <.001 to <.03). Significant decreases in anisotropy were detected in all white matter fiber tracts studied (P, <.001 to <.03) except the posterior limb of the internal capsule. CONCLUSION: In the children with developmental delay, diffusion-tensor MR imaging depicted decreases in anisotropy and increases in Dav in the white matter fiber tracts, which appeared to be normal at conventional MR imaging.

Anisotropy↗
PubMed2003

Proton MR spectroscopy in the diagnostic evaluation of suspected mitochondrial disease.

PURPOSE AND BACKGROUND: Mitochondrial diseases are a group of inherited disorders caused by a derangement of mitochondrial respiration. The clinical manifestations are heterogeneous, and the diagnosis is often based on information acquired from multiple levels of inquiry. MR spectroscopy has previously been shown to help detect an abnormal accumulation of lactate in brain parenchyma and CSF in association with mitochondrial disorders, but the frequency of detection is largely unknown. We sought to examine the frequency of detectable elevations of CNS lactate by proton MR spectroscopy in a population of children and young adults with suspected mitochondrial disease. METHODS: MR spectroscopy data evaluated for the presence or absence of abnormal brain or CSF lactate were compared with other clinical indicators of mitochondrial dysfunction for 29 patients with suspected mitochondrial disease during the years 1990 to 2000. Based on an independent review of the final diagnoses, the patients were divided into groups based on the probability of mitochondrial disorder. RESULTS: A total of 32 scans from 29 patients were reviewed. Of eight patients thought to have a definitive mitochondrial disorder on the basis of genetic, biochemical, or pathologic features, five were found to have abnormal brain or CSF lactate levels revealed by MR spectroscopy (for one patient in whom two images were acquired, one was negative and the other positive). Among the studies conducted using a multisection spectroscopic imaging technique, five of six showed elevated lactate in the brain parenchyma, six of six showed elevated lactate in the CSF, and five of six showed elevated lactate in both brain and CSF. Of 16 patients who were highly suspected of having mitochondrial disorders on the basis of clinical grounds alone but who were lacking genetic, biochemical, or pathologic confirmation, four had abnormal lactate levels shown by MR spectroscopy. Mitochondrial disorder was excluded for five patients, none of whom had CNS lactate shown by MR spectroscopy. CONCLUSION: Detection of CNS lactate by MR spectroscopy is useful in the diagnosis of mitochondrial disease. In our series of patients with confirmed mitochondrial disease, a high level of lactate shown by MR spectroscopy correlated well with other markers of mitochondrial disease. As with all other means used to diagnose mitochondrial disorders, MR spectroscopy does not depict elevated lactate in all cases. Abnormal CNS concentrations of lactate may be undetected by MR spectroscopy because of differences in the type of mitochondrial disorder, timing, severity, or location of the affected tissues and the site of interrogation.

Adolescent↗
PubMed2003

Combined stent placement and thrombolysis in acute vertebrobasilar ischemic stroke.

BACKGROUND AND PURPOSE: Acute vertebrobasilar ischemic stroke is often associated with high morbidity and mortality with limited therapeutic options. Endovascular treatment with thrombolysis has offered some hope for affected patients; however, overall outcomes have been less than satisfactory. In this report, we present the results of our approach in six consecutive cases of acute vertebrobasilar ischemic stroke by combined proximal vessel stent placement and thrombolysis. METHODS: Six consecutive cases were retrospectively reviewed for the clinical outcome of patients presenting to our institution with acute posterior circulation stroke who underwent cerebral revascularization including proximal arterial stent placement by using balloon-expandable coronary stents and intraarterial thrombolysis. All of these patients were initially evaluated by stroke team neurologists and imaged with MR, including diffusion-weighted imaging documenting acute posterior circulation stroke. MR angiography of the circle of Willis was also obtained. Short-term follow-up was conducted to assess National Institutes of Health stroke scores (NIHSS) and modified Rankin scores. RESULTS: In these six cases, a combined approach of proximal arterial stent placement (five cases of vertebral artery origin and one case of carotid and subclavian stent placement plus vertebral artery revascularization) and thrombolysis was performed at variable times after stroke onset (range, 30 hours to 5 days). Four of the six patients had good basilar artery recanalization (Thrombolysis in Myocardial Infarction [TIMI] grade 0-1 before tissue plasminogen activator thrombolysis and TIMI grade 2 after procedure). Four of six patients had excellent immediate recovery and were discharged to an acute rehabilitation unit or their homes with improved neurologic symptoms and functional status. Two patients died: one patient presented with coma at outset with an NIHSS of 38, and the other patient probably had reocclusion of the basilar artery within 24 hours despite initial postprocedural improvement. CONCLUSION: We demonstrate that, in the setting of acute stroke, stent placement in combination with revascularization and thrombolysis is practical and allows quick access to a clot and simultaneously increases perfusion through collaterals during the thrombolytic process. In particular, basilar thrombolysis may be facilitated by proximal vertebral stent placement as concomitant atheromatous vertebrobasilar stenosis is common.

Acute Disease↗
PubMed2003

Early characteristics of Sturge-Weber syndrome shown by perfusion MR imaging and proton MR spectroscopic imaging.

We report the case of a 9-month-old boy with Sturge-Weber syndrome and new onset of seizure. Perfusion MR imaging showed early changes compatible with impaired venous drainage in the affected hemisphere, whereas proton MR spectroscopic imaging revealed a focal parietal area of elevated choline without significant alteration of N-acetylaspartate levels. The perfusion and subtle metabolic abnormalities are comparable with the extent of the overlying leptomeningeal enhancement, illustrating the early pathophysiological manifestation of this disease.

Aspartic Acid↗
PubMed2002

Diffusion-weighted imaging and apparent diffusion coefficient maps in a case of intracerebral abscess with ventricular extension.

Previous findings have demonstrated the diagnostic usefulness of diffusion-weighted imaging in depicting specific features of a brain abscess. We report a case of a cerebral abscess, which ruptured into the ventricular system, including its findings on both diffusion-weighted images and apparent diffusion coefficient (ADC) maps. Purulent material within the left lateral ventricle, similar to that of the central abscess cavity, was strongly hyperintense on diffusion-weighted images. However, variable signal intensity changes were observed on the ADC map; these probably corresponded to regional variation of the concentration of protein in the purulent material. In this case, both diffusion-weighted images and ADC maps were important and complementary in the evaluation of ventricular extension of an intracerebral abscess.

Aged↗