Home About us Contact
|
Home About us Contact | ||
|
|
||
Magnetic Resonance Images (magnetic + resonance_image)
Kinds of Magnetic Resonance Images Selected AbstractsBrain Apparent Water Diffusion Coefficient Magnetic Resonance Image During a Prolonged Visual AuraHEADACHE, Issue 6 2010Robert Belvís MD (Headache 2010;50:1045-1049) Background., Reversible changes in brain magnetic resonance imaging (MRI) weighted in diffusion-weighted images (DWI) and apparent water diffusion coefficient (ADC) maps have been reported in acute stroke, epilepsy, eclampsia, and hypoglycemia, but they are contradictory regarding to migraine aura. Objective., A 41-year-old woman with known basilar migraine for 5 years consulted about a persistent visual aura (visual snow phenomenon) plus bilateral paresthesias in the extremities for 4 days. The headache was treated with success with 10 mg of wafer rizatriptan and 600 mg of ibuprophen. Methods., The neurologic and ophthalmologic examination were normal. An urgent brain MRI detected no lesions in T1, T2, fluid-attenuated inversion recovery, and DWI, but an abnormal signal appeared in the left occipital lobe in ADC and (r)ADC maps. The brain MRI angiography, carotid ultrasound study, transesophageal echocardiography, 24-hour cardiac Holter monitoring, and thrombophilia study were normal. Results., A new brain MRI 8 days after did not show any previous lesion in the same sequences. Conclusions., We present a patient with migraine and transitory abnormal signals in the ADC map of an occipital region during persistent visual aura. The clinical-radiological relationship is congruent. Some similar cases have showed these MRI signals during the aura, suggesting cytotoxic edema, without ischemic lesions in the MRI controls. Theses ADC images probably appear in complex auras. [source] Neuroanatomy and Volumes of Brain Structures of a Live California Sea Lion (Zalophus californianus) From Magnetic Resonance ImagesTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 10 2009Eric W. Montie Lateral view of MRI reconstruction of the brain surface of a California sea lion. The reconstruction placed in a parasagittal section through surrounding head structures. See Montie et al., on page 1523, in this issue. [source] Neuroanatomy of the Subadult and Fetal Brain of the Atlantic White-sided Dolphin (Lagenorhynchus acutus) from in Situ Magnetic Resonance ImagesTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 12 2007Eric W. Montie Abstract This article provides the first anatomically labeled, magnetic resonance imaging (MRI) -based atlas of the subadult and fetal Atlantic white-sided dolphin (Lagenorhynchus acutus) brain. It differs from previous MRI-based atlases of cetaceans in that it was created from images of fresh, postmortem brains in situ rather than extracted, formalin-fixed brains. The in situ images displayed the classic hallmarks of odontocete brains: fore-shortened orbital lobes and pronounced temporal width. Olfactory structures were absent and auditory regions (e.g., temporal lobes and inferior colliculi) were enlarged. In the subadult and fetal postmortem MRI scans, the hippocampus was identifiable, despite the relatively small size of this structure in cetaceans. The white matter tracts of the fetal hindbrain and cerebellum were pronounced, but in the telencephalon, the white matter tracts were much less distinct, consistent with less myelin. The white matter tracts of the auditory pathways in the fetal brains were myelinated, as shown by the T2 hypointensity signals for the inferior colliculus, cochlear nuclei, and trapezoid bodies. This finding is consistent with hearing and auditory processing regions maturing in utero in L. acutus, as has been observed for most mammals. In situ MRI scanning of fresh, postmortem specimens can be used not only to study the evolution and developmental patterns of cetacean brains but also to investigate the impacts of natural toxins (such as domoic acid), anthropogenic chemicals (such as polychlorinated biphenyls, polybrominated diphenyl ethers, and their hydroxylated metabolites), biological agents (parasites), and noise on the central nervous system of marine mammal species. Anat Rec, 2007. © 2007 Wiley-Liss, Inc. [source] Neuropsychological profile of children with subcortical band heterotopiaDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 11 2009MEGAN SPENCER-SMITH BPSYCSC PHD Aim, Subcortical band heterotopia (SBH) or ,double cortex' is a malformation of cortical development resulting from impaired neuronal migration. So far, research has focused on the neurological, neuroimaging, and genetic correlates of SBH. More recently, clinical reports and small sample studies have documented neuropsychological dysfunction in patients with this malformation. This study aimed to characterize further the phenotype of patients with SBH by describing the neuropsychological profiles of children. Method, Seven children (six females) aged 4 to 15 years were assessed for cognitive functioning (intellectual ability, processing speed, attention, working memory) and academic achievement (reading, spelling, arithmetic). Parents completed questionnaires examining their child's social skills and problem behaviours. Magnetic resonance images (MRI) conducted for routine clinical follow-up were coded by a paediatric neurologist. Genetic and seizure history were obtained from medical records. Results, There was variation in the neurological, neuroimaging, and genetic presentation of children in the sample. Impairments were observed in all areas of neuropsychological functioning examined. Intellectual ability was generally within the ,extremely low' range (full-scale IQ 44,74; performance IQ 45,72; verbal IQ 57,80). Generalized impairments in cognitive skills were typical, with severe impairments (scores greater than 2SD below the test mean) reported in processing speed, working memory, and arithmetic. Impairments in academic, social, and behavioural functioning were less generalized. No clear relationship between neuroimaging and neuropsychological impairments was found. Interpretation, Children with SBH demonstrate cognitive, academic, social, and behavioural problems, with the greatest difficulties in processing speed and complex cognitive skills. [source] Cross-sectional analysis of the association between age and corpus callosum size in chimpanzees (Pan troglodytes)DEVELOPMENTAL PSYCHOBIOLOGY, Issue 2 2010William D. Hopkins Abstract The CC is the major white matter tract connecting the cerebral hemispheres and provides for interhemispheric integration of sensory, motor and higher-order cognitive information. The midsagittal area of the CC has been frequently used as a marker of brain development in humans. We report the first investigation into the development of the corpus callosum and its regional subdivisions in chimpanzees (Pan troglodytes). Magnetic resonance images were collected from 104 chimpanzees (female n,=,63, male n,=,41) ranging in age from 6 years (pre-pubescent period) to 54 years (old age). Sustained linear growth was observed in the area of the CC subdivision of the genu; areas of the posterior midbody and anterior midbody displayed nonlinear growth during development. After adjusting for total brain size, we observed linear growth trajectories of the total CC and CC subdivisions of the genu, posterior midbody, isthmus and splenium, and nonlinear growth trajectories of the rostral body and anterior midbody. These developmental patterns are similar to the development of the CC in humans. As the growth curves of the CC mirrors growth seen in the percentage of white matter in humans, our results suggest chimpanzees show continued white matter development in regions related to cognitive development. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52:133,141, 2010 [source] Osseous abnormalities associated with collateral desmopathy of the distal interphalangeal joint: Part 1EQUINE VETERINARY JOURNAL, Issue 8 2009Miss S. G. Dakin Summary Reasons for performing study: Osseous abnormalities. associated with collateral ligament (CL) injury of the distal interphalangeal (DIP) joint have been documented using magnetic resonance imaging (MRI) but there is currently limited information about the frequency of osseous pathology associated with CL injury. Objectives: To determine the frequency of occurrence of osseous abnormality coexistent with CL injury of the DIP joint and describe the distribution and character of osseous lesions; and to establish if there was an association between osseous abnormality and increased radiopharmaceutical uptake (IRU). Hypotheses: There would be a higher incidence of osseous abnormality at the insertion of an injured CL than at the origin; and a relationship between the presence of osseous abnormality and duration of lameness. Materials and methods: Magnetic resonance images of 313 feet of 289 horses with foot pain and a definitive diagnosis of collateral desmopathy of the DIP joint were analysed retrospectively for presence and type of osseous abnormality in the middle and distal phalanges. Scintigraphic images were examined and the presence of IRU in the middle or distal phalanges recorded. Results: Osseous abnormalities were detected in 143 (45.7%) feet, 27 (18.8%) of which had osseous and CL injury alone, while the remaining 116 had CL related osseous injury and multiple injuries within the hoof capsule. Entheseous new bone and endosteal irregularity of the middle and distal phalanges were the most frequent types of osseous abnormality. There was a higher incidence of osseous abnormalities medially than laterally and at the ligament insertion than at the origin. There was a significant association between presence of IRU and osseous injury. Conclusions: A variety of osseous lesions of differing severity are associated with CL injury. Normal radiopharmaceutical uptake does not preclude significant osseous pathology associated with CL injury. Clinical relevance: Further studies are necessary in order to determine if osseous abnormalities associated with CL injury influence prognosis for return to performance. [source] Osseous abnormalities associated with collateral desmopathy of the distal interphalangeal joint.EQUINE VETERINARY JOURNAL, Issue 8 2009Part 2: Treatment, outcome Summary Reasons for performing study: There are currently few long-term follow-up data relating to recovery from injury of a collateral ligament (CL) of the distal interphalangeal (DIP) joint and limited information about the effect of associated osseous injury on prognosis. Objectives: To describe long-term follow-up results for horses with CL injury, with and without associated osseous injury; and to determine the effect of extracorporeal shock wave therapy (ECSWT) or radial pressure wave therapy (RPWT) on outcome. Hypotheses: Prognosis for return to performance for horses with CL-related osseous injury would be worse than for horses with CL injury alone. Methods: Magnetic resonance images from 313 feet of 289 horses with foot pain and a definitive diagnosis of collateral desmopathy of the DIP joint were analysed retrospectively for presence of osseous abnormality associated with the ligament origin or insertion and the middle and distal phalanges. Horses were assigned to groups according to the combination of their injuries. Type of treatment was recorded and follow-up information obtained. Thirty-two horses with additional sources of lameness were excluded from analysis of outcome. Results: Follow-up data were available for 182 horses, 55 of which had follow-up information for up to 2 years after presentation. Twenty-seven percent of horses with CL injury alone and 34% of horses with CL related osseous injury returned to their previous performance level. Prognosis for a combination of injuries to multiple soft tissue and osseous structures within the hoof capsule was substantially worse. There was no effect of ECSWT or RPWT on outcome. Conclusions: The presence of mild to moderate CL related osseous injury does not appear to influence prognosis compared with CL injury alone. Clinical relevance: Further studies of a larger number of horses are necessary in order to ascertain if specific types of osseous pathology influence return to performance levels. [source] Hyperostosis cranii in the elderly with various clinical symptomsGERIATRICS & GERONTOLOGY INTERNATIONAL, Issue 1 2004Makoto Sohmiya We report three elderly patients with hyperostosis cranii. Patient 1 had two episodes of unconsciousness; Patient 2, headache; and Patient 3, dementia. On the basis of Moore's classification using skull films, Patients 1 and 2 showed hyperostosis frontoparietalis and Patient 3 had hyperostosis frontalis interna. Electroencephalography showed transient generalized spike and slow wave complexes over the frontal lobes in Patient 1. Magnetic resonance images showed frontal lobes compressed by the thickness of the frontal bones in all patients and the thickness of the parietal bones in Patients 1 and 2. Since the findings in the present cases and those in the literature suggest that hyperostosis cranii could show unexpected neuropsychiatric symptoms, hyperostosis cranii should be checked in elderly patients whose presenting symptoms include epilepsy, dementia, psychiatric disease, headache and so on. Magnetic resonance images should be helpful in examining the relationship between clinical symptoms and the deformation of the brain by the skull. [source] Magnetic resonance images of the globus pallidus in patients with idiopathic portal hypertension: A quantitative analysis of the relationship between signal intensity and the grade of portosystemic shuntJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 5 2006Takeshi Fukuzawa Abstract Background and Aim:, To elucidate a quantitative relationship between hyperintensity of the globus pallidus on T1-weighted magnetic resonance images (MRI) and portosystemic shunt (PSS) in portal hypertension. Methods:, Fifteen patients with idiopathic portal hypertension (IPH) and 44 patients with liver cirrhosis (LC) underwent brain MRI to asses signal intensity at the globus pallidus and Doppler sonography to examine the blood flow volume of PSS. Blood manganese (Mn) levels were examined in 36 patients and neuropsychological tests were performed in 15 patients without overt hepatic encephalopathy. Results:, Pallidal hyperintensity on MRI was more prominent in patients with IPH than in patients with LC. There was no correlation between MRI pallidal hyperintensity and the severity of liver dysfunction or hepatic encephalopathy. The grade of hyperintensity correlated well with the grade of PSS. The correlation was stronger in patients with IPH than in patients with LC. The plasma ammonia level and whole blood Mn level significantly correlated with MRI pallidal hyperintensity, but blood Mn level showed a stronger correlation than plasma ammonia. Conclusion:, Hyperintensity of the globus pallidus on T1-weighted MRI correlated with the development of PSS independent of liver cell function. This brain image should be an index of the grade of PSS rather than a landmark of chronic liver failure. [source] Big cat scan: Magnetic resonance imaging of the tigerJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 1 2004Thomas M Snow SUMMARY In August 2002, we performed MRI scans on a female juvenile Bengal tiger. We present the clinical course, imaging and autopsy findings, and some comparative anatomy of the tiger brain and skull. Magnetic resonance images of a tiger have not previously been published. [source] A retrospective study of the MRI findings in 18 dogs with stifle injuriesJOURNAL OF SMALL ANIMAL PRACTICE, Issue 9 2009E. Barrett Objectives:To make an objective assessment of the usefulness of magnetic resonance imaging in the diagnosis of meniscal damage and cranial cruciate ligament disease in the canine stifle by comparing magnetic resonance imaging findings with surgical findings. Methods:Magnetic resonance images of 18 stifles from 18 dogs which had undergone magnetic resonance imaging for the investigation of stifle disease were reviewed. For every stifle, the menisci and cranial cruciate ligaments were assessed according to predetermined criteria. The magnetic resonance imaging findings were compared with the reported surgical findings and the sensitivity, specificity, positive and negative predictive values (PPV and NPV) were calculated using the surgical findings as the gold standard. Kappa analysis was used as an objective measure of agreement between surgical and magnetic resonance imaging findings. For 11 stifles, meniscal evaluation by three different observers was used to measure interobserver agreement using Kappa analysis. Results:Magnetic resonance imaging was demonstrated to be an accurate technique in the detection of meniscal injury (k=0·86), with excellent interobserver agreement (k=0·89 to 1·0). Disruption of cranial cruciate ligament continuity and an increase in ligament intensity were found to be useful criteria in the diagnosis of cranial cruciate ligament rupture. Clinical Significance:Magnetic resonance imaging offers a non-invasive alternative to exploratory surgery in the evaluation of cranial cruciate ligament and meniscal disease. [source] In vivo analysis of the post-natal development of normal mouse brain by DTINMR IN BIOMEDICINE, Issue 4 2007Pierre Larvaron Abstract The water diffusion characteristics of wild-type mouse brains have been studied in vivo by DTI to follow developmental changes. Here, axial (,//) and radial (,,) diffusivities and fractional anisotropy were measured from the fifth day of life (P5) and at three other post-natal ages (P12, P19 and P54). Magnetic resonance images were collected from a single sagittal slice in the middle of the two hemispheres; ROI were chosen in nine different structures of both grey and white matter. Fractional anisotropy (FA) from P5 onwards distinguished structures of both white and grey matter, even though myelination had yet to occur. Between P5 and P54, a significant increase in FA was observed in the genu of the corpus callosum due to a significant decrease in ,, whereas ,// remained stable. Many other significant variations of ,// and ,, were measured in different structures. They were substantially correlated with axon and myelin maturation which are responsible for the main evolutions of the brain during its post-natal development. These quantitative data show that in vivo characterization of the anatomy and microstructure of the normal mouse brain during development is possible. The normative data will greatly improve the characterization of abnormal development in the transgenic mouse brain. Copyright © 2006 John Wiley & Sons, Ltd. [source] Distinct subtypes of myelitis in systemic lupus erythematosusARTHRITIS & RHEUMATISM, Issue 11 2009J. Birnbaum Objective Myelitis causes pain, weakness, and sphincteric deficits, and is 1,000-fold more prevalent in patients with systemic lupus erythematosus (SLE) than in the general population. For the last century, descriptions of SLE myelitis have been primarily limited to case reports. In contrast, larger-scale cohort studies have revealed that myelitis occurring in the idiopathic demyelinating diseases (i.e., multiple sclerosis versus neuromyelitis optica) represents distinct syndromes. This study was undertaken to determine whether SLE myelitis similarly encapsulates distinct syndromes. Methods We analyzed a cohort of 22 patients with SLE and myelitis. Patients were assessed for neurologic variables related to myelitis and for clinical and serologic features of SLE. Magnetic resonance images of the spine, cerebrospinal fluid profiles, and autoantibody profiles were obtained. Results Eleven patients presented with signs of gray matter dysfunction (i.e., flaccidity and hyporeflexia), whereas 11 patients presented with signs of white matter dysfunction (i.e., spasticity and hyperreflexia). Patients with gray matter dysfunction were more likely to have irreversible paraplegia (P < 0.01), despite presenting with a monophasic versus polyphasic course (P = 0.01), higher levels of SLE activity (mean SLE Disease Activity Index 9.8 versus 2.0; P = 0.01), and a cerebrospinal fluid profile indistinguishable from bacterial meningitis. Prior to irreversible paraplegia, these patients presented with prodromes of fever and urinary retention, but were misdiagnosed by physicians of different specialties as having urinary tract infections. Patients with white matter dysfunction were more likely to meet criteria for neuromyelitis optica (P = 0.04) and were also more likely to have antiphospholipid antibodies (lupus anticoagulant) (P = 0.01). Conclusion Our findings indicate that SLE myelitis encapsulates 2 distinct and previously unrecognized syndromes that can be distinguished clinically by gray matter versus white matter findings. Recognition of fever and urinary retention as prodromes of irreversible paraplegia may allow earlier diagnosis and treatment in SLE patients presenting with gray matter findings. [source] Cortical folding difference between patients with early-onset and patients with intermediate-onset bipolar disorderBIPOLAR DISORDERS, Issue 4 2009Jani Penttilä Objectives:, Cerebral abnormalities have been detected in patients with bipolar disorder (BD). In comparison to BD with a later onset, early-onset BD has been found to have a poorer outcome. However, it is yet unknown whether neuroanatomical abnormalities differ between age-at-onset subgroups of the illness. We searched for cortical folding differences between early-onset (before 25 years) and intermediate-onset (between 25 and 45 years) BD patients. Methods:, Magnetic resonance images of 22 early-onset BD patients, 14 intermediate-onset BD patients, and 50 healthy participants were analyzed using a fully automated method to extract, label, and measure the sulcal area in the whole cortex. Cortical folding was assessed by computing global sulcal indices (the ratio between total sulcal area and total outer cortex area) for each hemisphere, and local sulcal indices for 12 predefined regions in both hemispheres. Results:, Intermediate-onset BD patients had a significantly reduced local sulcal index in the right dorsolateral prefrontal cortex in comparison to both early-onset BD patients and healthy subjects, and lower global sulcal indices in both hemispheres in comparison to healthy subjects (p < 0.05, Bonferroni corrected). Brain tissue volumes did not differ between groups. Conclusions:, This study provided the first evidence of a neuroanatomic difference between intermediate-onset and early-onset BD, which lends further support to the existence of different age-at-onset subgroups of BD. [source] Acute encephalopathy with biphasic seizures and late restricted diffusion on MRI in a Japanese child living in the USADEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 9 2008David E Traul MD PhD We report an 18-month-old Japanese female living in the USA whose clinical course and radiographic findings were consistent with acute encephalopathy with biphasic seizures and late reduced diffusion (AESD). She was initially diagnosed with complex febrile seizures. However, on day 3 of admission, she had a cluster of complex partial seizures and the onset of a global developmental regression. In contrast to the normal magnetic resonance image of the brain obtained on admission, subsequent imaging demonstrated transient subcortical diffusion-weighted abnormalities in the white matter of the bilateral posterosuperior frontal, parietal, temporal, and occipital regions, with sparing of the perirolandic area. One year later, her developmental delay, although improved, persisted and she continued to experience sporadic seizures while being treated with topiramate monotherapy. Repeat imaging showed diffuse, poorly defined, increased T2 signals in the white matter of the posterosuperior frontal, parietal, temporal and occipital regions and diffuse cerebral volume loss. Previous reports of AESD have been limited to children aged under 4 years living in Japan. With the identification of this case, it is important that all physicians, not only those in Japan, who care for children with febrile seizures be aware of AESD and its associated neurological morbidity. [source] Pseudo-clitoromegaly associated with congenital prepubic sinusINTERNATIONAL JOURNAL OF UROLOGY, Issue 7 2006MASA HAYASE Abstract, We operated on a 12-year-old girl who had clitoromegaly and a sinus on the midline prepubic area congenitally. The prepubic sinus appeared to point to the clitoris on the preoperative magnetic resonance image, but the relation between the sinus and clitoromegaly was unclear. Gray-brown discharge was emitted at the site of dissection between the prepuce and clitoris and the size of the clitoris became normal. The sinus was excised, revealing a tract 1.5 cm long that extended to the retropubic sinus, and ended in a fibrous tract that was linked to the clitoris. This suggested pseudo-hypertrophy because of the discharge collected in the end of the prepubic sinus. [source] Chronic expanding hematoma in the psoas muscleINTERNATIONAL JOURNAL OF UROLOGY, Issue 12 2005TOSHINARI YAMASAKI Abstract, We report an unusual case of chronic expanding hematoma in the psoas muscle. A 53-year-old man was admitted for evaluation of a mass shadow in the left lower lung field on chest X-rays. He had also been suffering from dull left back pain. A computed tomography scan showed a cystic lesion with a rim enhancement in the left retroperitoneal space. Mixed signal intensity in a mosaic pattern was seen on a T2-weighted magnetic resonance image. We could not rule out a suspicion of a neoplastic intratumoral hemorrhage. Due to increased pain and the definite diagnosis, surgery was performed. Histopathological examination confirmed the diagnosis of chronic expanding hematoma. The expansion process is thought to be due to the irritant effects of blood and its breakdown products, which cause repeated exudation and bleeding from capillaries in the granulation tissues. [source] Isolated Plexiform Neurofibroma: Treatment with Three-Dimensional Conformal Radiotherapy,THE LARYNGOSCOPE, Issue 7 2004Thomas C. Robertson MD Abstract Objectives: To present a case of an unusual benign tumor of the tongue treated successfully with radiotherapy. Study Design: Case report. Methods: Retrospective chart review. Results: A 60-year-old man presented with a painful submucosal lesion of the tongue base. Computed tomography showed an infiltrative soft-tissue mass involving the left base of the tongue. Operative biopsy revealed plexiform neurofibroma. Because of the patient's operative risk and the potential morbidity of surgical resection, he was treated with three-dimensional conformal radiotherapy (3DCRT). His treatment was accomplished using a five-field arrangement treating exclusively the mass lesion to a total tumor dose of 60 Gy. After treatment, the patient's tongue pain resolved, and he noted minimal transient xerostomia. Serial follow-up radiographic examinations showed the base of tongue mass to be slightly smaller 4 months after treatment. The most recent follow-up magnetic resonance image reveals a further decrease in size of the mass. The patient is now over 3 years out from treatment. Conclusions: Solitary plexiform neurofibroma of the tongue base is a rare tumor. These benign neoplasms are usually treated with either observation or surgical excision. This case demonstrates that, when significant symptoms necessitate active management, these lesions may be successfully treated with minimal morbidity using 3DCRT. The ability of this technique to deliver a conformal radiation dose to the tumor volume while sparing the surrounding normal tissues may expand the application of radiotherapy in the treatment of these benign lesions of the head and neck. [source] REVERSIBLE JUMP MARKOV CHAIN MONTE CARLO METHODS AND SEGMENTATION ALGORITHMS IN HIDDEN MARKOV MODELSAUSTRALIAN & NEW ZEALAND JOURNAL OF STATISTICS, Issue 2 2010R. Paroli Summary We consider hidden Markov models with an unknown number of regimes for the segmentation of the pixel intensities of digital images that consist of a small set of colours. New reversible jump Markov chain Monte Carlo algorithms to estimate both the dimension and the unknown parameters of the model are introduced. Parameters are updated by random walk Metropolis,Hastings moves, without updating the sequence of the hidden Markov chain. The segmentation (i.e. the estimation of the hidden regimes) is a further aim and is performed by means of a number of competing algorithms. We apply our Bayesian inference and segmentation tools to digital images, which are linearized through the Peano,Hilbert scan, and perform experiments and comparisons on both synthetic images and a real brain magnetic resonance image. [source] Dermoid cyst with magnetic resonance image of sack-of-marblesBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2008N. Fujimoto No abstract is available for this article. [source] Transitional cell carcinoma of the urinary bladder with regional lymph node involvement treated by cystectomyCANCER, Issue 10 2003Clinicopathologic features associated with outcome Abstract BACKGROUND Patients with transitional cell carcinoma (TCC) of the urinary bladder metastatic to regional lymph nodes (LN) typically have a poor prognosis. However, some patients are cured by radical cystectomy alone. The goal of this study was to identify predictors of survival in this cohort. METHODS The authors identified 154 patients with TCC metastatic to regional LNs treated by cystectomy between 1970 and 1998. Clinical characteristics collected included age, gender, and preoperative computed tomographic or magnetic resonance image scan findings, as well as neoadjuvant and adjuvant therapy. Pathologic features evaluated included multifocality, size, pathologic stage, grade, and margin status of the primary tumor, as well as the number, location, and bilaterality of the positive LNs. Capsular penetration, greatest linear extent, and surface area of the largest metastatic LN deposit were also recorded. The Kaplan,Meier method was used to evaluate survival rates. Cox proportional hazards models were used to identify predictors of outcome. RESULTS The mean follow-up was 4.5 years (range, 0.1,13.9 years). In a multivariate setting, only adjuvant chemotherapy and the number of positive LNs were associated significantly with death from TCC. Patients treated adjuvantly with chemotherapy were 2.1 times less likely to die of their disease (P = 0.005). Each increase in one positive LN increased the risk of death from TCC by 20% (P < 0.001). Recursive partitioning indicated that the optimal cutoff point to predict death from TCC was five or more positive LNs. CONCLUSIONS Adjuvant chemotherapy and the number of positive LNs were associated significantly with death from TCC. Cancer 2003;10:2425,31. © 2003 American Cancer Society. DOI 10.1002/cncr.11370 [source] The clinical presentation of mitochondrial diseases in children with progressive intellectual and neurological deterioration: a national, prospective, population-based studyDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 5 2010CHRISTOPHER M VERITY Aim, Our aim was to study the clinical presentation, mode of diagnosis, and epidemiology of mitochondrial disorders in children from the UK who have progressive intellectual and neurological deterioration (PIND). Method, Since April 1997, we have identified patients aged 16 years or younger with suspected PIND through the monthly notification card sent to all UK consultant paediatricians by the British Paediatric Surveillance Unit. Clinical details obtained from reporting paediatricians are classified by an Expert Group. Results, By July 2008, 2493 cases of PIND had been reported, among which there were 112 children (69 males, 43 females) with mitochondrial diseases presenting between birth and 14 years 7 months (median 12mo), divided into 13 subgroups. In some instances, clinical features were characteristic of mitochondrial disease, but many children presented non-specifically with combinations of developmental delay, hypotonia, failure to thrive, and seizures; 16 children had multisystem disease at presentation. Mortality was high: 40 children had died. Blood and/or cerebrospinal fluid lactate measurements were abnormal in 87 children, and 47 of 78 brain magnetic resonance images showed increased basal ganglia signal. Definite diagnoses were usually made by muscle enzyme or genetic studies. Interpretation, This is a unique population-based study of the mitochondrial disorders that cause childhood neurodegenerative disease. It provides detailed information about the clinical presentation and investigation of these complex cases. [source] Cognitive visual dysfunctions in preterm children with periventricular leukomalaciaDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 12 2009ELISA FAZZI MD PHD Aim, Cognitive visual dysfunctions (CVDs) reflect an impairment of the capacity to process visual information. The question of whether CVDs might be classifiable according to the nature and distribution of the underlying brain damage is an intriguing one in child neuropsychology. Method, We studied 22 children born preterm (12 males, 10 females; mean age at examination 8y, range 6,15y; mean gestational age 30wks, range 28,36wks) with periventricular leukomalacia, spastic diplegia, normal intelligence (mean Full-scale IQ 84; mean Verbal IQ 97; mean Performance IQ 74), and normal visual acuity, focusing on higher visual functions. Brain magnetic resonance images (MRI) were analysed to establish the presence of lesions along the primary optic pathway, in the occipitoparietal and occipitotemporal regions. Results, Most children displayed an uneven cognitive profile, with deficits in visual object recognition, visual imagery, visual,spatial skills, and visual memory, and sparing of visual associative abilities, non-verbal intelligence, and face and letter recognition. Conventional brain MRI did not document major alterations of parietal and temporal white matter, or cortical alteration of areas involved in visual associative functions. Interpretation, We suggest a widespread involvement of higher visual processing systems, involving both the ventral and dorsal streams, in preterm children with periventricular leukomalacia. The lack of major alterations on conventional MRI does not exclude the possibility of malfunctioning of higher visual processing systems, expressing itself through discrete CVDs. Possible mechanisms underlying these neuropsychological deficits are discussed. [source] Neuromagnetic Source Localization of Epileptiform Activity in Patients with Graphogenic EpilepsyEPILEPSIA, Issue 11 2006Naoaki Tanaka Summary:,Purpose: To clarify the source localization of epileptiform activity by using magnetoencephalography (MEG) in patients with graphogenic epilepsy. Methods: MEG and simultaneous EEG were recorded with a 204-channel whole-head MEG system in two patients with graphogenic epilepsy. During the MEG recordings, the patients performed a set of tasks comprising mental arithmetic calculation, speaking, moving the right arm in a manner resembling writing, writing, and thinking of writing. Equivalent current dipoles (ECD) were calculated for epileptiform discharges on MEG by using a single-dipole model. The ECD were superimposed on the magnetic resonance images of the patients. Results: The task of writing provoked seizures, in which both patients jerked the right arms. Thinking of writing also induced these seizures. In both patients, EEG associated with the seizures showed bursts of spike-and-slow-wave complexes predominantly in the centroparietal region. MEG also showed epileptiform discharges corresponding to the EEG bursts. ECDs obtained from the discharges were clustered in the left centroparietal area. Conclusions: Thinking of writing was a trigger for the seizures, as well as the task of writing. The source of the epileptiform discharge associated with the seizures was localized in the unilateral centroparietal area. The findings suggest that the centroparietal region plays an important role in the pathophysiology underlying these two graphogenic epilepsy cases. [source] A Magnetoencephalographic Study of Patients with Panayiotopoulos SyndromeEPILEPSIA, Issue 7 2005Osamu Kanazawa Summary:,Purpose: Panayiotopoulos syndrome (PS) is a newly identified type of benign childhood epilepsy characterized by ictal vomiting and eye deviation. It is usually accompanied by occipital spike discharges; however, its classification as an early-onset benign childhood occipital epilepsy is controversial. To characterize this condition further, we examined the localization of equivalent current dipoles (ECDs) of spike discharges by magnetoencephalography (MEG) in patients with PS. Methods: We studied 13 patients with a mean age at time of examination of 5 years (range, 3,14 years). MEG was measured by using a whole-head 204-channel neuromagnetometer with simultaneous EEG recordings. The estimated locations of ECDs of each peak of the spike discharges were overlaid on magnetic resonance images of the brain. Results: Eleven (84.6%) patients showed clustered ECDs in the areas alongside the parietooccipital sulcus (eight of 13; 61.5%) and/or the calcarine sulcus (four of 13; 30.8%). Despite Fp-O synchronization of the spike discharges in the scalp EEG of five patients, no frontal locations of ECDs were found. All five (38.5%) boys with sylvian seizures, who also showed clustered ECDs in rolandic areas, had an earlier age at onset and higher seizure frequency than did other patients. ECD orientations were regular in all but one patient, who showed irregular and dispersed ECDs alongside bilateral calcarine sulci. Conclusions: Our results demonstrate localized cortical hyperexcitability in the areas alongside major cortical sulci in PS and indicate that PS is closely related to benign childhood epilepsy with centrotemporal spikes. [source] Focal Ictal , Discharge on Scalp EEG Predicts Excellent Outcome of Frontal Lobe Epilepsy SurgeryEPILEPSIA, Issue 3 2002Gregory A. Worrell Summary: ,Purpose: To determine whether a focal ,-frequency discharge at seizure onset on scalp EEG predicts outcome of frontal lobe epilepsy (FLE) surgery. Methods: We identified 54 consecutive patients with intractable FLE who underwent epilepsy surgery between December 1987 and December 1996. A blind review of EEGs and magnetic resonance images (MRIs) was performed. Lesional epilepsy is defined as presence of an underlying structural abnormality on MRI. Results: Overall, 28 (52%) patients were seizure free, with a mean follow-up of 46.5 months. Presence of a focal ,-frequency discharge at seizure onset on scalp EEG predicted seizure-free outcome in lesional (p = 0.02) and nonlesional (p = 0.01) epilepsy patients. At least 90% of patients who had either lesional or nonlesional epilepsy were seizure free if scalp EEG revealed a focal , discharge at ictal onset. Moreover, logistic regression analysis showed that focal ictal , pattern and completeness of lesion resection were independently predictive of seizure-free outcome. Ictal onset with lateralized EEG activity of any kind and postresection electrocorticographic spikes did not predict surgical outcome (p > 0.05). Conclusions: Only about 25% of FLE surgical patients have a focal ,-frequency discharge at seizure onset on scalp EEG. However, its presence is highly predictive of excellent postsurgical seizure control in either lesional or nonlesional FLE surgical patients. [source] Magnetic resonance microscopy of the equine hoof wall: a study of resolution and potentialEQUINE VETERINARY JOURNAL, Issue 5 2006M. D. KELLER Summary Reasons for performing study: Obtaining magnetic resonance images of the inner hoof wall tissue at the microscopic level would enable early accurate diagnosis of laminitis and therefore more effective therapy. Objectives: To optimise magnetic resonance imaging (MRI) parameters in order to obtain the highest possible resolution of the structures beneath the equine hoof wall. Methods: Magnetic resonance microscopy (MRM) was performed in front feet from 6 cadaver horses using T2 -weighted fast spin echo (FSE-T2), and T1 -weighted gradient echo (GRE-T1) sequences. Results: In T2 weighted FSE images most of the stratum medium showed no signal, however the coronary, terminal and sole papillae were visible. The stratum lamellatum was clearly visible and primary epidermal lamellae could be differentiated from dermal lamellae. Conclusion: Most structures beneath the hoof wall were differentiated. Conventional scanners for diagnostic MRI in horses are low or high field. However this study used ultra-high field scanners currently not available for clinical use. Signal-to-noise ratio (S/N) increases as a function of field strength. An increase of spatial resolution of the image results in a decreased S/N. S/N can also be improved with better coils and the resolution of high field MRI scanners will increase as technology develops and surface array coils become more readily available. Potential relevance: Although MR images with microscopic resolution were obtained ex vivo, this study demonstrates the potential for detection of lamellar pathology as it occurs. Early recognition of the development of laminitis to instigate effective therapy at an earlier stage and may improve the outcome for laminitic horses. Clinical MR is now readily available at 3 T, while 4 T, 7 T and 9 T systems are being used for human whole body applications. [source] IMAGING STUDY: Prefrontal cortex morphometry in abstinent adolescent marijuana users: subtle gender effectsADDICTION BIOLOGY, Issue 4 2009Krista Lisdahl Medina ABSTRACT Adult human studies suggest frontal dysfunction associated with chronic marijuana (MJ) use, but due to continued neuromaturation, adult studies may not generalize to adolescents. This study characterized prefrontal cortex (PFC) morphometry in chronic MJ-using adolescents following 1 month of monitored abstinence. Data were collected from MJ users (n = 16) and controls (n = 16) aged 16,18. Extensive exclusionary criteria included co-morbid psychiatric and neurologic disorders. Substance use and anatomical measures were collected after 28 days of monitored abstinence. PFC volumes were ascertained from manual tracing by reliable raters on high-resolution magnetic resonance images. After controlling for lifetime alcohol use, gender and intracranial volume, MJ users did not differ from controls in PFC volume. However, marginal group-by-gender interactions were observed (P < 0.09): female MJ users demonstrated comparatively larger PFC volumes while male MJ users had smaller volumes compared with same-gender controls. Further, group status and total PFC volume interacted in predicting executive functioning (P < 0.05). Among MJ users, smaller PFC total volume was associated with better executive functioning while the opposite pattern was seen among the controls. These preliminary results indicate that gender may moderate the relationship between MJ use and PFC morphometry. Given the relationship between larger PFC total volumes and poorer executive functioning among MJ users, female MJ users may be at increased risk for neurocognitive consequences. Future research will measure PFC gray and white matter separately and follow boys and girls over adolescence to examine the influence of MJ use on neurodevelopment. [source] Migraine and stroke , why do we talk about it?EUROPEAN JOURNAL OF NEUROLOGY, Issue 3 2006C. Lampl Data from observational studies suggest that migraine may be a risk factor for stroke. Furthermore, a significant association between migraine and ischemic stroke (IS) has been demonstrated in population and case,control studies. The risk of IS appears to be higher for migraine with aura than for migraine without aura. The pathogenesis is not known but several studies report some common biochemical mechanisms in the two diseases. Meta-analysis also demonstrates that subjects with migraine are at higher risk of showing white matter abnormalities on magnetic resonance images than are those without migraine. [source] Integrating modelling and experiments to assess dynamic musculoskeletal function in humansEXPERIMENTAL PHYSIOLOGY, Issue 2 2006J. W. Fernandez Magnetic resonance imaging, bi-plane X-ray fluoroscopy and biomechanical modelling are enabling technologies for the non-invasive evaluation of muscle, ligament and joint function during dynamic activity. This paper reviews these various technologies in the context of their application to the study of human movement. We describe how three-dimensional, subject-specific computer models of the muscles, ligaments, cartilage and bones can be developed from high-resolution magnetic resonance images; how X-ray fluoroscopy can be used to measure the relative movements of the bones at a joint in three dimensions with submillimetre accuracy; how complex 3-D dynamic simulations of movement can be performed using new computational methods based on non-linear control theory; and how musculoskeletal forces derived from such simulations can be used as inputs to elaborate finite-element models of a joint to calculate contact stress distributions on a subject-specific basis. A hierarchical modelling approach is highlighted that links rigid-body models of limb segments with detailed finite-element models of the joints. A framework is proposed that integrates subject-specific musculoskeletal computer models with highly accurate in vivo experimental data. [source] | ||||||||||||||||||||||||||||||||||