Changes in brain high energy phosphate metabolite and pH levels were studied using serial phosphorus (P)-31 magnetic resonance spectroscopy (MRS) in an epidural balloon cat model. The balloon was inflated with 1, 2, 3, or 4 ml of water at 1 ml/sec and deflated after obtaining a spectrum 4 minutes later. Serial spectra, intracranial pressure (ICP), physiological parameters, and the pupil sizes were observed for 1 hour. The mean ICP after balloon inflation increased to between 36 ± 3 and 130 ± 6 mmHg. Some animals showed oculomotor paralyses. Phosphocreatine, adenosine triphosphate, phosphodiester, and phosphomonoester levels suddenly decreased after inflation and gradually recovered after balloon deflation. Acidosis progressed with cerebral compression for 4 minutes and gradually recovered. All changes and recovery were volume related. This study demonstrates the potential of P-31 MRS for noninvasive, serial, in vivo measurements of critical high energy phosphate metabolites and intracellular pH after head injury.
Proton magnetic resonance spectroscopy (MRS) with the depth resolved surface coil spectroscopy technique and the 1331-2662 water suppression method was used to examine two cerebral ischemia patients and 10 normal volunteers. In all cases, N-acetyl-aspartate, creatine, phosphocreatine, and residual lipid were clearly observed. No lactic acid peak was observed in normal volunteers, but a large lactic acid peak appeared in the early stage of cerebral ischemia. This MRS abnormality was observed before abnormalities appeared in conventional imaging such as computed tomographic scanning and magnetic resonance imaging.
The importance of diffuse axonal injury (DAI) and early intracranial sequelae was studied in 107 patients with diffuse and focal brain injuries. Comprehensive neuropathological study was also undertaken in 24 fatal patients. The mortality rate was clearly the highest in traumatic subarachnoid hemorrhage, followed by acute subdural hematoma, cerebral contusion with delayed hematoma formation, traumatic intracerebral hematoma, diffuse cerebral swelling, DAI with classical features, and finally nearly normal on computed tomographic scans. The mean flow velocities in the middle cerebral artery recorded by transcranial Doppler ultrasound were variable in diffuse brain injury, but commonly decreased on the hematoma side depending on increased intracranial pressure and decreased cerebral perfusion pressure in focal brain injury. Deep-seated hemorrhagic lesions did not expand in diffuse brain injury, but sizable hematoma developed within 24 hours in focal brain injury. The platelet count was significantly lower in patients with poor outcomes in focal brain injury. Histological evidence of classical DAI was found in eight (50%) of 16 cases with focal brain injury. DAI of varying severity is the common subjacent lesion in patients with severe head injury, but the final outcome varies greatly with different lesion types.
The clinical benefits and hemodynamic effects of continuous alprenolol infusion for control of hypertension in the acute stage of ruptured cerebral aneurysms were investigated. Twenty-five patients manifesting systemic hypertension (> 160/100 mmHg) were treated with alprenolol, a β-adrenergic antagonist, phentolamine, an α-adrenergic antagonist, and trimethaphan camsilate, a ganglionic blocker, given intravenously. All drugs decreased the mean arterial blood pressure significantly. However, alprenolol decreased the heart rate and cardiac index while phentolamine increased them. Alprenolol also decreased arterial catecholamine and renin activity, but caused no change in central venous pressure, pulmonary capillary wedge pressure, pulmonary vascular resistance, and systemic vascular resistance. The results indicate the usefulness of continuous alprenolol infusion for the control of acute hypertension in hemorrhagic cerebrovascular disease. The mode of action of alprenolol is also discussed.
Intramedullary spinal AVMs fed by the anterior spinal artery cannot be embolized without risking unacceptable motor deficits, since the feeding arteries may supply the corticospinal tract (CST). An 8-year-old boy underwent successful embolization of such an AVM under general anesthesia using intermittent infusion of embolic material with monitoring of the CST integrity with the corticospinal motor evoked potential (MEP). This case illustrates the value of corticospinal MEP monitoring during therapeutic procedures under general anesthesia which risk interrupting the blood supply to the CST.
A 66-year-old male presented with clinical features of hemifacial spasm. Cerebral angiograms disclosed an arteriovenous malformation (AVM) in the cerebellopontine angle. The hemifacial spasm was caused by a dilated feeding artery of the AVM compressing the facial nerve at the root exit zone. Surgery was not initially performed because of his age and absence of AVM rupture. However, the AVM was associated with a small aneurysm in the feeding artery, which rapidly grew during 20 days after discharge and ruptured causing subarachnoid hemorrhage. The aneurysm was clipped and the feeding artery of the AVM partially obliterated. Careful angiographic examination for associated aneurysms and consequent surgical obliteration to prevent hemorrhage are suggested in cases of AVM.
The authors report a case of cerebellopontine angle epidermoid presenting as typical hemifacial spasm. A 33-year-old male had experienced intermittent right hemifacial spasm for 2 years. Cranial nerve examination was otherwise normal, including auditory and trigeminal nerve functions. Metrizamide computed tomographic cisternography and magnetic resonance imaging demonstrated a characteristic epidermoid tumor. The tumor was totally removed. Postoperatively, no facial spasm or other facial nerve dysfunction was noted.
A rare case of a cystic cavernous angioma in a 20-year-old female was diagnosed preoperatively by magnetic resonance imaging and computed tomography. Total surgical removal resulted in a successful recovery. Cystic cavernous angioma is benign and can be completely removed. The importance of magnetic resonance imaging in the differential diagnosis is emphasized.
The neurosurgical application was evaluated of a flow-directed oximetry thermodilution catheter for measurement of oxygen saturation in the jugular vein, which reflects cerebral blood flow (CBF). The catheter allows estimation of changes in CBF during carotid endarterectomy and therapeutically induced hypertension in the management of delayed vasospasm after subarachnoid hemorrhage.