Correlation between cerebral visual impairment and magnetic resonance imaging in children with neonatal encephalopathy

To identify brain lesions most often associated with cerebral visual i mpairment (CVI) after neonatal encephalopathy and to evaluate the prognostic value of MRI for visual outcome, the authors reviewed visual assessments and brain MRI of 80 infants and young children with documented perinatal hypoxic-ischaemic and/or haemorrhagic insults. MRIs were classified according to the severity of lesions at the optic radiations and at the visual cortex; visual acuity was tested with the acuity card procedure. Among the 48 children found to have a CVI, 42 had moderate to severe lesions of the optic radiations and 19 had lesions of the visual cortex. In both cases visual acuity was statically correlated with MRI grading, but the damage at the optic radiations was the better predictor. Early detection of abnormal MR findings in the visual cortex and especially, at the optic radiations may indicate which infants with neonatal encephalopthy should receive longitudinal visual assessment and specific rehabilitation and educational management.     

Cat scratch disease: magnetic resonance imaging findings

Cat scratch disease is an infectious lymphadenitis frequently occurring in children and adolescents. We present the magnetic resonance imaging findings of two patients with this disease. In both cases, lymphadenopathy was characterized by extensive stranding of the surrounding soft tissues, consistent with the inflammatory nature of this condition. Magnetic resonance imaging can be diagnostic and may obviate the need for invasive means of evaluation in patients suspected of having cat scratch disease.     

Gliomatosis cerebri: findings with computed tomography and magnetic resonance imaging

OBJECTIVES: In an effort to critically examine the antitumor activity of altretamine (hexamethylmelamine) as salvage therapy of platinum-refractory ovarian cancer, the Gynecologic Oncology Group initiated a Phase II trial of the agent administered in this clinical setting. METHODS: Altretamine was administered at a dose of 260 mg/m2 orally for 14 days in a 28-day course. Treatment was continued until disease progression or unacceptable side effects prevented further therapy. A total of 36 patients (median age: 56.5) were treated on this trial, of whom 33 were evaluable for toxicity and 30 for response. All patients had previously received either cisplatin or carboplatin and paclitaxel. RESULTS: The major side effect was emesis (grade 3-4, 7/33, 21%). The objective response rate was 10% (one complete response, two partial responses). CONCLUSION: We conclude that altretamine has limited activity in platinum-refractory ovarian cancer.     

Craniocerebral magnetic resonance imaging measurement and findings in Lesch-Nyhan syndrome

OBJECTIVE: To provide the first comprehensive magnetic resonance imaging (MRI) assessment of brain in a series of patients with Lesch-Nyhan syndrome (LNS), with emphasis on basal ganglia measurements. DESIGN: Routine readings of MRI studies, repeated reading in random order blinded to subject diagnosis, and 3-dimensional volumetric measures of basal ganglia regions. SETTING: The Johns Hopkins Hospital, Baltimore, Md. PATIENTS: Seven patients with LNS who have hypoxanthine guanine phosphoribosyltransferase levels less than 1.6% and characteristic clinical features of the disorder, which include hyperuricemia, cognitive impairment, and dystonic movement disorder, were compared with 7 age-matched control subjects. Five of the 7 patients demonstrated self-injurious behavior. MRI studies were performed using general anesthesia because of the severity of the movement disorder. MAIN OUTCOME MEASURES: Measurement of brain regions from MRI-obtained images. RESULTS: Routine readings described mild cerebral atrophy in 2 of 7 patients, but no caudate or putamen abnormalities were reported. However, on the directed blinded rereading, small caudates were suspected in 5 of 7 cases, and abnormalities in cerebral size and cranium were identified. Volumetric studies of the patients with LNS confirmed a 34% decrease in caudate volume (P<.001), a 17% decrease in total cerebral volume (P<.03), and a 12% decrease in putamen volume (P=.19). CONCLUSIONS: To our knowledge, this is the first demonstration of consistent neuroanatomic abnormalities in LNS. The findings of reduced basal ganglia volume are consistent with the dystonic movement disorder.     

Case report: rapidly progressive neuropathic arthropathy in syringohydromyelia--radiographic and magnetic resonance imaging findings

A rapidly progressive neuropathic shoulder joint in a patient with syringohydromyelia is presented. He developed marked destruction of the shoulder joint over 5 weeks. The MRI findings in the pre- and post-resorptive phases of the arthropathy are presented for the first time. Low signal intensity areas are observed in the medullary cavity of the bone on both T1- and T2-weighted spin-echo images even before the actual resorptive process starts. Additional major findings are the joint effusion and synovial thickening.     

Hypoxic-ischaemic encephalopathy: early and late magnetic resonance imaging findings in relation to outcome

Sixteen infants with hypoxic-ischaemic encephalopathy (HIE) were studied using serial magnetic resonance imaging (MRI) up to the age of 2 years. The infants had regular neurological and developmental assessments. An nuclear magnetic resonance (NMR) score was devised to quantify the early and late MRI findings and a neurological optimality score was used to quantify abnormal neurological signs at the time of the final examination. The follow up MRI score was compared with the neonatal MRI score and the outcome of the child. There was a strong positive correlation between the neonatal and follow up MRI scores and between MRI scores and optimality score. All infants with a normal outcome had patchy white matter abnormalities. All infants with an abnormal outcome had extensive white matter abnormalities. The outcome was most severe in those infants with additional basal ganglia atrophy with or without cyst formation. Infants with mild HIE who are developmentally normal at the age of 2 years do not have normal MRI scans and may be at risk of minor neurological problems by school age. Bilateral basal ganglia abnormalities are associated with severe developmental delay, but infants with mainly white matter and cortical abnormalities have less severe problems despite extensive tissue loss.     

Subacute combined degeneration: clinical, electrophysiological, and magnetic resonance imaging findings

OBJECTIVE: Vitamin B12 deficiency is a systemic disease that often affects the nervous system. One of the most prevalent manifestations is subacute combined degeneration (SCD) of the spinal cord. To access the clinical, electrophysiological, and structural abnormalities associated with SCD, a study was conducted in nine patients. METHODS: Clinical, electrophysiological (electroneurography, somatosensory and motor evoked potentials), and MRI evaluations were performed in patients before and after treatment. RESULTS: The most prominent clinical and electrophysiological findings in all patients were dysfunctions of the posterior column. Corresponding hyperintense lesions in the posterior column of the spinal cord were found in two patients by T2 weighted MRI. Damage to the central motor pathway was identified in four patients. Demyelinating neuropathy was present in one patient and axonal neuropathy in four. All patients showed improvement of their symptoms after treatment with cobalamin. Abnormalities of the spinal cord on MRI disappeared early in recovery. Motor evoked potentials and median somatosensory evoked potentials typically normalised after treatment, whereas tibial somatosensory evoked potentials remained abnormal in most patients. CONCLUSIONS: Clinical, electrophysiological, and MRI findings associated with SCD in vitamin B12 deficiency are diverse. Thus vitamin B12 deficiency should be considered in the differential diagnosis of all spinal cord, peripheral nerve, and neuropsychiatric disorders.     

Behavioral activity and visual evoked potentials to photic stimuli following septal lesions in rats.

Conducted 4 experiments with a total of 63 male Holtzman albino rats to analyze electrophysiological correlates of hyperreactivity to stimuli following septal lesions, locomotor reactivity, and averaged visual evoked response (VER) to photic stimuli. While septal lesions exaggerated behavioral reactivity to flashes, they enhanced elaboration of late components of VERs at the visual cortex, a development normally associated with reduced behavioral reactivity. This lesion-induced dissociation between behavioral reactivity and VERs occurred under test conditions in which intensity of flashes, background illumination, and spacing of flash series were varied. Results suggest that septal lesions reduce electrocortical arousal to photic stimuli, but it remains unclear to what extent the changes are cortical and/or subcortical in origin. (32 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Variability in visual cortex activation during prolonged functional magnetic resonance imaging

OBJECTIVE: To review the EEG features of ring 20 syndrome in two patients and determine the characteristic pattern of this syndrome. The features of our cases and 24 patients reported in the literature will be discussed. SUBJECTS AND METHODS: Report of two patients and review of literature. RESULTS: The two patients had intractable epilepsy since childhood. Their clinical seizures were mostly complex partial seizures. Often the patients seizures were of prolonged duration. Ictal EEG revealed characteristic slow waves, and sharp waves. The slow waves were (1) usually synchronous high-voltage slow waves with or without a spike component predominantly in the frontal and frontopolar areas, (2) sometimes showed a change in frequency every several seconds, (3) continued for a long period, and (4) easily spread diffusely. The sharp waves were 5-6 Hz irregular and diffuse discontinuous sharp waves, and sometimes appeared predominantly in the centroparietal area. The clinical seizure pattern and EEG findings were similar in the 24 published cases. CONCLUSIONS: These EEG findings may be a characteristic feature of ring 20 syndrome and thus may be useful as a diagnostic clue.     

Acute hemorrhagic leukoencephalitis: recovery and reversal of magnetic resonance imaging findings in a child

A case of acute hemorrhagic leukoencephalitis (AHLE) in a 6-year-old girl is reported. The presentation was typical for acute hemorrhagic leukoencephalitis, with acute onset of a rapidly progressive neurologic disorder with asymmetric involvement of brain, with polymorphonuclear predominant peripheral leukocytosis and cerebrospinal fluid pleocytosis. Cerebrospinal fluid findings not previously reported included elevation of IgG and the presence of myelin basic protein. Additional previously unreported findings were striking abnormalities on magnetic resonance imaging (MRI) of the brain, in contrast to normal findings on computed tomography (CT). The child was treated with high dose intravenous steroids and made a full recovery, with a parallel disappearance of all of her cerebrospinal fluid abnormalities and almost all of her abnormalities on MRI. Detailed examination of cerebrospinal fluid and MRI of brain should facilitate early diagnosis in other cases of suspected acute hemorrhagic leukoencephalitis and high-dose steroid therapy may lead to improved clinical outcomes.     

Tears of the medial collateral ligament: magnetic resonance imaging findings and associated injuries

For 23 patients with a surgically proven tear of the medial collateral ligament the findings from magnetic resonance imaging (MRI) of the knee were evaluated retrospectively. MRI revealed the tear in all cases, although when the injury was severe, distinguishing high-grade partial tears from complete tears was difficult. Physical examination had indicated a tear in 22 (96%) of the cases. A high prevalence of associated cruciate and meniscal injuries was seen (in 23 [100%] and 12 [52%] of the cases respectively). Tears of the fibular collateral ligament occurred in 13 (57%) of the patients and at least one bony infraction in 22 (96%); most of the infractions were in the lateral compartment. Infractions of the lateral femoral condyle were frequently geographic (in 14 [70%] of the 20 cases) or impacted (in 5 [25%]). The spectrum of injuries associated with tears of the medial collateral ligament was consistent with the findings of previous studies focusing on cruciate and meniscal abnormalities; the minor variations were likely due to the severity of valgus stress in this sample.     

Epidural spinal infection. Variability of clinical and magnetic resonance imaging findings

STUDY DESIGN: This study evaluates the magnetic resonance characteristics of spinal epidural abscesses and their associated disc space infections. OBJECTIVES: The results were correlated with history, clinical, and laboratory findings to provide guidelines for early and appropriate diagnosis of epidural spinal infections. SUMMARY OF BACKGROUND DATA: Imaging signs of spinal infections have been reported before, but not with special attention to early clinical and imaging findings. METHODS: Thirteen patients (10 men, 3 women; age range, 32-64 years) with progressive sensorimotor deficit were studied. All patients had a neurologic examination after admission and a magnetic resonance imaging scan done within the first 48 hours. In all cases, T1-weighted images before and after administration of gadolinium were obtained. T2-weighted images were acquired in eight cases as well. Ten patients subsequently underwent open surgery; in three cases, a percutaneous biopsy and drainage was performed. RESULTS: Cervical discitis was found in five patients, and thoracic discitis was seen in another five cases. Three patients had an epidural infection without a concomitant discitis. Neurologic and clinical findings varied considerably. Despite clinical signs of spinal cord involvement, a spinal cord lesion was demonstrated only once. Signal change in T2-weighted images may be the first sign of disc space infection. Because a neurologic deficit may occur before any change is visible, follow-up examinations may be required if epidural infection is suspected on clinical grounds. CONCLUSIONS: Magnetic resonance imaging is the appropriate method for diagnostic work-up of progressive neurologic deficit resulting from epidural infection.     

Effect of levodopa therapy on visual evoked potentials and visual acuity in amblyopia

Between 10 and 11 years after children were vaccinated with Vi capsular polysaccharide of Salmonella typhi or meningococcal A + C control vaccine in a double blind randomized trial, we traced 83 subjects, aged 16-20 years. A blood sample was taken for determination of Vi antibody titres in both groups by radioimmunoassay. TO and TH titres were also done to assess if the participants had had recent exposure to typhoid fever. Fifty-eight percent of subjects in both groups had protective levels of Vi antibody against Salmonella typhi (a titre greater than 1 microgram ml-1). There was no significant difference in the levels of Vi antibodies in the cases versus the controls (p = 0.5). Two of the children who had received meningococcal A + C vaccine had recently had typhoid fever. Our data show that adolescents in typhoid endemic areas have high levels of Vi antibodies regardless of previous vaccination status, suggesting that Vi antibodies are acquired in adolescence by a large percentage of the population in this area. Moreover, Vi vaccination has led to ongoing antibody production in greater than 50% of Vi vaccinated children in an endemic area for a period of 10 years. Ongoing antigenic exposure may have contributed to these antibody levels.     

Imaging of the pediatric orbit and visual pathways: computed tomography and magnetic resonance imaging

Tumors of the small bowel are uncommon and seldom suspected on a clinical basis. Together with the relative inaccessibility of the small bowel to endoscopic investigation, the rarity of these tumors undoubtedly delays the diagnosis. Small bowel tumors may be an interesting field of application for enteroscopy, which now can be readily performed with dedicated enteroscopic evaluation in patients with suspected small bowel neoplasia could improve prognosis and treatment. Enteroscopy may also play an important role in the surveillance of inherited polyposis syndromes, as in other precancerous condition of the small bowel. In Peutz-Jeghers syndrome it may reduce polyp-induced complications and improve planning for surgery; in familial adenomatous polyposis it may contribute to preventing upper gastrointestinal tract cancer.     

Neuronal generators of visual evoked potentials in humans: visual processing in the human cortex

PURPOSE: We wished to define the localization of cortical generators of visual (pattern) evoked potentials (VEP) and the temporal sequence of activation in the occipital region. METHODS: In 4 candidates for epilepsy surgery, a large array of subdural electrodes was placed over occipital areas. Checkerboard pattern reversal stimuli were generated and the epileptogenic focus was localized and functionally mapped. Magnetic resonance imaging did not show any occipital lesions in any of the 4 patients. RESULTS: The area first activated was the lingual gyrus in the mesial occipital lobe (negative potential peaks at approximately 70 ms), followed by an area superior to the calcarine fissure (negative peaks at approximately 80 ms). Later (starting at approximately 90 ms), there were positive potentials over the occipital pole and lingual gyrus, followed by potentials at the lateral occipital lobe. CONCLUSIONS: These data support the idea that VEP are generated in the mesial and lateral occipital cortex by different circumscribed neuronal generators with different latencies of activation. The scalp-recorded N1 and P1 potential peaks most likely derive from the progressive activation of neuronal masses in different regions of the occipital lobe.     

Soft tissue osteosarcoma with telangiectatic features: MR imaging findings in two cases

Extraskeletal osteosarcomas are rare tumors, and the telangiectatic variety is the least common histological variety in this group. This report describes the clinical and MR imaging findings in two cases arising in the pretibial soft tissues. Both tumors demonstrated marked inhomogeneity with T2-weighted spin echo and STIR sequences. One of the tumors revealed numerous fluid levels within the lesion. A review of the MRI features of these tumors is provided. Osteosarcoma with telangiectatic features should be considered in the differential diagnosis of a soft tissue mass with fluid-fluid levels in patients 40 years of age or older.     

Visual evoked potentials generator model derived from different spatial frequency stimuli of visual field regions and magnetic resonance imaging coordinates of V1, V2, V3 areas in man

Visual evoked potentials (VEPs) to pattern reversal vertical bar stimuli were recorded from 24 scalp derivations (including zygomatic and inion) referenced to digitally linked earlobes in 50 controls. 1, 2 and 4 cpd patterns were presented as full field (FF) stimuli, on Upper Hemifields (UHF) and Lower Hemifields (LHF), upper and lower quadrants and with the occlusion of central and peripheral UHF and LHF. VEPs to octant stimuli were also recorded with 2 cpd patterns. N1, P1 and N2 components were recorded from posterior and inion derivations with FF stimuli, from posterior derivations with LHF stimuli, only from inion leads with UHF stimuli, from derivations ipsilateral to stimuli with quadrants and octants, and consistently from midline derivations only with lower quadrants. Polarity inverted sequences (iN1-iP1-iN2) were recorded from the other scalp derivations, with similar latency and spatial frequency sensitivity as N1-P1-N2. Single Equivalent Dipole (ED) calculations were performed on N1 and P1 recorded in the different stimulus conditions. Our findings contradict previous hypotheses on VEP generators and contradict the predictions of VEPs polarity and distribution based on the "cruciform model" of VEPs generators. In order to explain the distribution of VEPs to upper and lower half fields and to quadrant and octants, we propose a model based on the position of the medial and occipito-polar surface of visual cortex in man.     

Advances in magnetic resonance imaging: applications in body imaging

Recent developments in the field of endocrine cell biology and pathology at both morphological and molecular levels are briefly outlined and discussed as a basis for endocrine tumor characterization. The main tools available for identifying the endocrine nature of the tumors, their pathogenetic interpretation. and experimental reproduction with special emphasis on tumor antecedents are reported. Based on this, classifications of endocrine tumors of the pancreas and gastrointestinal tract are developed, covering most clinical (hyperfunctional syndromes included), pathological, and biological patterns, with special emphasis on tumor prognosis.     

Directional asymmetries in interhemispheric transmission time: evidence from visual evoked potentials

The hypothesis was tested that interhemispheric transfer time (IHTT), as measured in the latency of bilaterally recorded visual evoked potentials, is directionally asymmetric, i.e. that an IHTT is faster for transmission from right-to-left hemisphere, than from left-to-right. A meta-analysis of 18 experiments within the published literature reporting visual evoked potential IHTTs indicates a significant experiment-wise predominance of faster right-to-left IHTTs. A new experiment is also reported in which significantly faster right-to-left IHTT was found in visual evoked potentials recorded from parietal electrodes to lateral visual field presentations while subjects performed a task requiring complex stimulus recognition and analysis, and a choice response.