ABSTRACT
A 22-year-old man had leg weakness and decreased hearing. A diagnosis of neurosarcoidosis was made, based on neuroimaging studies and lymph node biopsy. Post-treatment neuroimaging, in particular magnetic resonance imaging along with clinical course, is useful in monitoring response to therapy.
Subject(s)
Nervous System Diseases/diagnosis , Sarcoidosis/diagnosis , Adult , Humans , Leg , Male , Muscle Weakness/etiology , Nervous System Diseases/complications , Sarcoidosis/complicationsABSTRACT
An important goal of EEG research is to obtain practical methods to improve the spatial resolution of scalp-recorded potentials, i.e., to make surface data more accurately represent local underlying brain sources. This goal may be somewhat different from that of "localizing brain activity with EEG," since the latter approach often involves prior assumptions about the nature of sources. In this paper, we demonstrate that spline-Laplacian, a relatively new approach that can yield dramatic improvement in spatial resolution when average electrode spacing is less than about 3 cm. This approach is mostly independent of assumptions about sources and models of the head. The demonstration involves computer simulations, evoked potentials, normal spontaneous EEG, and epileptic spikes.
Subject(s)
Brain/physiopathology , Computer Simulation , Electroencephalography/instrumentation , Models, Neurological , Models, Theoretical , Signal Processing, Computer-Assisted/instrumentation , Arousal/physiology , Electroencephalography/statistics & numerical data , Epilepsy/physiopathology , Evoked Potentials/physiology , Humans , Reaction Time/physiologyABSTRACT
A "picture book" of surface potentials, Laplacians, and magnetic fields due to distributed, neocortical sources is presented. The mathematically simulated data is based on 4200 current sources at the macrocolumn scale. Estimated scalp surface maps are based on the three-concentic spheres model of the head. Emphasis is placed on the effects of sampling with a limited number of electrodes, the choice of reference electrode, and the use of the spline Laplacian to improve spatial resolution. The spline Laplacian is applied to median and ulnar nerve somatosensory evoked potentials and to auditory evoked potentials including P300. Substantial improvement in spatial resolution over conventional methods is obtained. The implementation of practical high resolution EEG systems based on the spline Laplacian is considered.
Subject(s)
Brain Mapping , Brain/physiology , Computer Simulation , Evoked Potentials, Auditory/physiology , Evoked Potentials, Somatosensory/physiology , Models, Neurological , Algorithms , Electrodes , Electroencephalography , Humans , Magnetoencephalography , Reaction Time , Reference ValuesABSTRACT
Two patients with unusual central nervous system sarcoid were investigated using computed tomography and magnetic resonance imaging, as well as other x-ray studies. A patient with intramedullary involvement of the spinal cord as well as nerve root involvement was examined. Follow-up examination after treatment with steroids showed a return to normal. The second patient had optic nerve involvement as well as two intracranial parenchymal lesions and granulomatous arachnoiditis. In this patient magnetic resonance imaging offered no advantages over computed tomography in the orbit but was significantly more accurate intracranially.
Subject(s)
Brain Diseases/diagnosis , Magnetic Resonance Imaging , Sarcoidosis/diagnosis , Spinal Cord Diseases/diagnosis , Tomography, X-Ray Computed , Adult , Brain/pathology , Cauda Equina/pathology , Humans , Male , Optic Nerve/pathology , Optic Nerve Diseases/diagnosis , Peripheral Nervous System Diseases/diagnosis , Spinal Cord/pathologyABSTRACT
This study examined the role of colloids versus crystalloids in pulmonary edema associated with the increased pulmonary microvascular permeability secondary to thrombin-induced pulmonary microembolism. Each of 23 healthy dogs received an intravenous injection of thrombin and a fibrinolysis inhibitor, which induced a microembolic state with increased (fivefold) pulmonary lymphatic flow and a lymph/plasma (L/P) protein ratio typical of a permeability change. Seven dogs received no treatment, eight received 15 ml/kg 10% dextran 40 (D40), and eight received 60 ml/kg Ringer's lactate solution (RL). Pulmonary water was measured serially by thermal conductivity and terminally by wet/dry weights. This preparation produced significant hemolysis; however, L/P ratios of hemoglobin approached unity in all groups. Initially there was hemoconcentration, which was reversed by RL and even more so by D40. Both D40 and RL temporarily raised the pulmonary artery and pulmonary artery wedge pressures to 15 mm Hg; D40 more than doubled the cardiac output of control or RL subjects--this was associated with a reduced pulmonary arteriolar resistance (P less than 0.05). In the early stage PaO2 was better maintained with D40 (P less than 0.02). Lymph flow increased and was comparable in all groups, as were lung water and lung weight, which tripled in all three groups. Results of this study indicated that in the presence of a pulmonary microvascular leak, colloids in doses that produced comparable microvascular pressures did not increase lung water and did not accumulate in the pulmonary interstitium. Colloids were superior to crystalloids in maintaining cardiac output, pulmonary vascular resistance, and oxygen tension in the early period after microembolism.U
Subject(s)
Capillary Permeability , Pulmonary Edema/physiopathology , Pulmonary Embolism/physiopathology , Animals , Body Water/analysis , Capillary Permeability/drug effects , Colloids/pharmacology , Dextrans/pharmacology , Dogs , Female , Hemodilution , Hemodynamics/drug effects , Lung/analysis , Male , Pulmonary Edema/metabolism , Pulmonary Embolism/chemically induced , Pulmonary Embolism/metabolism , Thrombin/pharmacologyABSTRACT
Double-indicator dilution methods can be used for measurement of lung water. The thermal conductivity method is based on heat as a diffusible and conductivity as a non-diffusible indicator. In the present study we correlated lung thermal volume with gravimetrical measurement of extravascular lung water after thrombin-induced microembolization in dog lungs. The embolization was accompanied by significantly increased vascular permeability and accumulation of interstitial water. Under these conditions there was a close correlation between the two methods of measuring lung water (r = 0.78, p less than 0.01).
Subject(s)
Body Water/analysis , Lung/analysis , Pulmonary Embolism/physiopathology , Animals , Dogs , Female , Thermal Conductivity , ThermodilutionABSTRACT
Pulmonary microembolization was induced by infusion of thrombin during inhibition of the fibrinolytic system. After embolization cardiac output decreased, pulmonary vascular resistance and pulmonary arterial pressure increased. There was a transient decrease in PaO2. Immediately after embolization there was an increased permeability indicated by tremendous increase in lymph flow with a constant lymph/plasma protein ratio. The lymph/plasma ratio for hemoglobin and for FITC-Dextran (mw 150 000) also increased indicating leakage of large molecules. The increased permeability was accompanied by a significant increase in extra-vascular lung-water as measured both with the thermal conductivity and the dry/wet weight method.
