A comparative study on the efficacy of 10% hypertonic saline and equal volume of 20% mannitol in the treatment of experimentally induced cerebral edema in adult rats

<p>Abstract</p> <p>Background</p> <p>Hypertonic saline and mannitol are commonly used in the treatment of cerebral edema and elevated intracranial pressure (ICP) at present. In this connection, 10% hypertonic saline (HS) alleviates cerebral edema more effectively than the equal volume of 20% mannitol. However, the exact underlying mechanism for this remains obscure. This study aimed to explore the possible mechanism whereby 10% hypertonic saline can ameliorate cerebral edema more effectively than mannitol.</p> <p>Results</p> <p>Adult male Sprague-Dawley (SD) rats were subjected to permanent right-sided middle cerebral artery occlusion (MCAO) and treated with a continuous intravenous infusion of 10% HS, 20% mannitol or D-[1-³H(N)]-mannitol. Brain water content (BWC) as analyzed by wet-to-dry ratios in the ischemic hemisphere of SD rats decreased more significantly after 10% HS treatment compared with 20% mannitol. Concentration of serum Na⁺and plasma crystal osmotic pressure of the 10% HS group at 2, 6, 12 and 18 h following permanent MCAO increased significantly when compared with 20% mannitol treated group. Moreover, there was negative correlation between the BWC of the ipsilateral ischemic hemisphere and concentration of serum Na⁺, plasma crystal osmotic pressure and difference value of concentration of serum Na⁺and concentration of brain Na⁺in ipsilateral ischemic hemisphere in the 10% HS group at the various time points after MCAO. A remarkable finding was the progressive accumulation of mannitol in the ischemic brain tissue.</p> <p>Conclusions</p> <p>We conclude that 10% HS is more effective in alleviating cerebral edema than the equal volume of 20% mannitol. This is because 10% HS contributes to establish a higher osmotic gradient across BBB and, furthermore, the progressive accumulation of mannitol in the ischemic brain tissue counteracts its therapeutic efficacy on cerebral edema.</p

Intracranial CSF flow in pediatric hydrocephalus: evaluation with cine-MR imaging

1) To describe the pattern of normal intracranial CSF flow in children and 2) to demonstrate altered CSF flow patterns in pediatric hydrocephalus and ventriculomegaly with flow-sensitized cine-MR examinations. Cardiac gated, multiframe, gradient echo sequences on a 1.5-T system were displayed on a closed loop cine format and compared to standard MR images. Areas of normal flow and areas of diminished flow were determined. 1) In normal children, the CSF flow follows a consistent pattern with a to-and-fro movement of flow in the aqueduct, foramen of Magendie, and in the dorsal and ventral subarachnoid space at the cervicomedullary junction. 2) In patients with ventricular enlargement, the flow studies showed regional abnormalities of the CSF flow patterns: specifically, lack of flow and hyperdynamic flow. Cine-MR for CSF flow evaluation is a useful adjunct to routine MR in the evaluation of pediatric hydrocephalus because it can assist in determining the probable level of CSF obstruction

Needle aspiration of intramedullary and intradural extramedullary masses of the spinal canal

Ten intramedullary and two intradural extramedullary masses of the spinal canal were evaluated with 16 separate needle aspirations. Cord fluctuance at air myelography and/or low density within the cord on computed tomography determined the level of aspiration. The condition of two patients with cystic neoplasms and one with syringohydromyelia improved after fluid removal. Endomyelography demonstrated the extent of eight intramedullary cavities. In syringohydromyelia, this information was used in determining the surgical approach. Aspiration and tissue biopsy enabled successful diagnosis of two cases of intradural extramedullary masses of unknown etiology. Needle aspiration yields valuable diagnostic information and is safe when proper guidelines are followed

The injured spinal cord. Evaluation with magnetic resonance and intraoperative sonography

MR is now the study of choice in evaluating both the acutely and previously injured spinal cord. A number of crucial diagnoses can be made with MR that are difficult to obtain otherwise. The discovery of acute disk herniation in association with a fracture/dislocation may indicate the need to remove the disk and stabilize the patient on a relatively urgent basis, and the approach to the stabilization procedure (either anterior or posterior) can be determined by the MR findings. Hemorrhage outside the cord may require immediate surgical attention, and identification of abnormal signals from the cord itself consistent with hemorrhage or edema may help to explain the patient's clinical status. Our experience indicates that obtaining an MR in acutely injured patients who have incomplete injuries is particularly helpful in their surgical management. The presence of intramedullary or extramedullary cysts in the previously injured spine can explain a worsening clinical picture and direct the surgeon to the proper area (or areas) for decompression. Flow-sensitive studies currently under evaluation are giving a greater insight into the dynamics of these cysts. Late decompression of cord tissue and roots requires accurate preoperative MR evaluation of possible bone or disk impingement on neural tissue. In surgery of both the acute and chronically injured spine, intraoperative sonography plays a crucial role. The adequate shunting of intramedullary and subarachnoid cysts, the confirmation of the efficaciously placed Harrington rods, the demonstration of removal of compressive bone or disk fragments, and the uncovering of important but unanticipated abnormalities such as subligamentous hematoma or an incidentally herniated disk all attest to sonography's value in the operating room. MR preoperatively and sonography intraoperatively are important tools utilized in the care of spine-injured patients