Levovist has a significant echo-enhancing effect in patients with an inadequate bone window. We evaluated its diagnostic value in transcranial Doppler sonography (TCD), including its ability to assess hemodynamic parameters of intracranial arteries. The 12 studied patients (5 women and 7 men, ranging in age from 62 to 78 y) comprised 7 with intracranial aneurysms (5 non-ruptured, 2 ruptured), 3 with cerebral infarction, 1 with cerebral hematoma and 1 with brain trauma. According to the precontrast imaging quality, patients were assigned to one of two groups: group 1, highly insufficient native Doppler signal on TCD examination (n=7); group 2, satisfactory waveforms detected on TCD (n=4). Levovist was administered intravenously at a concentration of 300 mg/ml with a total dose of 2 ml (administered in 12 s) or 5 ml (in 30 s). Levovist-induced enhancement characteristics of the Doppler frequency spectrum were then analyzed.In group 1, Levovist improved the diagnostic utility of TCD, and increases of Vs, Vm and Vd after a 2-ml bolus injection were 7.4±1.6%, 9.4±1.5% and 13.8±2.6%, respectively. After a 5-ml bolus injection the increases of Vs, Vm and Vd were 12.7±2.1%, 13.8±1.7% and 16.1±1.9%, respectively. Either a 2- or 5-ml bolus injection revealed a significant increase of velocity (p<0.05). In group 2, use of the echo-enhancement agent did not influence the Doppler velocity. The mean duration of clinically useful signal enhancement with a 5-ml bolus injection (250 to 395 s, mean 301 s) was significantly higher than that with a 2-ml bolus injection (120 to 250 s, mean 188 s) (p<0.05).These results indicate that a significant enhancement of flow velocity after Levovist injection was found only in patients with an insufficient acoustic bone window, and no significant change in flow velocity on TCD was detected in patients with a sufficient acoustic bone window.
Sixty-eight hydrocephalic patients were treated with a shunt system that incorporated a SOPHY programmable valve. This device is very effective for treating disorders of CSF circulation. However, when the valve is placed on the scalp, it produces artifacts on MR imaging due to its small magnetic rotor, and may cause necrosis of the scalp above it. On the other hand, when it is positioned on the chest, MR artifacts decrease and exchanging the valve devices becomes easier. Therefore, we have positioned the device on the chest. However, some complications were encountered, such as the turning over of the valve in the subcutaneous pocket and the twisting of the shunt tube. Moreover, the shunt tube may stretch due to growth of the neck during development in infantile patients or extension of the neck during exercise. These complications are associated only with subcutaneous placement on the chest, so we conclude that such a valve, if placed on the chest, should be placed in a lower position on the chest, and if MR examination will not be performed in the foreseeable future, we recommend that it be placed on the occipital scalp, especially in infantile patients.
With the development of MRI and MRA, many unruptured aneurysms have been detected and treated. Nevertheless, not a few false-positive and false-negative cases are found. We investigate aneurysms that were suspected after screening MRA at the neurosurgical outpatient clinic and the features of aneurysms detected not with MRA but with DSA were studied. Seventy-six patients (85 aneurysms) were suspected due to screening MRA and DSA was performed in 64 (71 aneurysms) of them. Correct diagnosis of cerebral aneurysms with MRA was obtained in 44 patients (45 aneurysms, 63.4%), while false-negative cases were found in 17 patients (plus 20 aneurysms) and false-positive cases in 7 patients (10 aneurysms). The accuracy was 97.2% in ACA, 93% in MCA, 94.4% in VA-BA, and 78.9% in IC, while the sensitivity 100%, 88.2%, 81.8%, 64.7% and the specificity 96.5%, 94.4%, 96.7%, 91.9%, respectively. The features of aneurysms correctly diagnosed with MRA were relatively large ACA, including AcoA, MCA and VA-BA aneurysms, whereas the features of aneurysms undetected with MRA were small IC aneurysms (1-3mm in diameter), especially at the C2-3 portion. These aneurysms at the C2-3 portion or at unusual portions tended to be difficult to detect even with 3D-CTA. Though most of the aneurysms detected with DSA but not with MRA tended to be small and not interventionally treated in the present study, we should pay attention to the fact that these aneurysms are overlooked despite the possibility that they may become enlarged or rupture. Though ruptured aneurysms were surgically treated with only MRA or 3D-CTA without conventional angiography in these days, we recommend the examination of the unruptured cases, which are usually asymptomatic and not hasty, with precise inspection by target MIP, high-performance 3D-CTA or DSA.
This study examines whether platelet-activating factor (PAF) is involved in the occurrence of vasospasm after subarachnoid hemorrhage (SAH). A vasospasm model was produced in rabbits, with animals in six experimental groups receiving two subarachnoid injections of autologous arterial blood with the addition of one of the following; saline (Control Group 1), 25% dimethyl sulfoxide (Control Group 2), PAF (1, 2.5, 5, or 10 micrograms), CV6209 (10 or 100 micrograms), BN52021 (10 or 100 micrograms), or anti-PAF immunoglobulin G (IgG, 50 or 500 micrograms). No significant differences were detected between Control Groups 1 and 2 with regard to neurological deterioration and basilar artery constriction after SAH was induced. Administration of PAF together with autologous blood aggravated neurological deficits in a dose-dependent manner (r = 0.724, p < 0.001) and produced basilar artery constriction at two doses each of 2.5 micrograms (p < 0.05), 5 micrograms (p < 0.01), and 10 micrograms (p < 0.01). Neurological deterioration was prevented in rabbits receiving an intracisternal administration of either PAF antagonist CV6209 or BN52021 or anti-PAF IgG (p < 0.01 at a total dose of 20 micrograms and p < 0.05 at a total dose of 200 micrograms CV6209, p < 0.01 at total doses of 20 and 200 micrograms BN52021, and p < 0.01 at total doses of 100 and 1000 micrograms anti-PAF IgG). A reduction in basilar artery constriction was achieved by the injection of anti-PAF IgG (p < 0.05 at total doses of 100 and 1000 micrograms). Histological examination at autopsy on Days 14 to 21 showed mainly ischemic changes in the brain, including selective neuronal necrosis and cerebral infarction. The control and PAF groups showed marked ischemic changes. On the other hand, no ischemic changes were noted in the anti-PAF IgG group, and only 9% of animals in the CV6209 group and 25% in the BN52021 group demonstrated selective neuronal necrosis or infarction. This study thus provides evidence to support the role of PAF in the pathogenesis of vasospasm after SAH.
To clarify the correlation between middle cerebral artery flow velocity during temporary occlusion of the internal carotid artery (ICA) and post-occlusion neurological deficits, the balloon occlusion test was carried out during pre-operative angiography. Seven patients, were selected (four men and three women; aged 35-70 years) . The diagnosis was carotid bifurcation stenosis in two patients, internal carotid-ophthalmic aneurysm in two, carotid-cavernous fistula in one, ICA aneurysmal dilatation due to aortitis in one, and tumor of the neck in one. Two patients had a transient neurological deficit during the balloon occlusion test. The mean pre-occlusion velocities were Vs: 65, Vm: 48 and Vd: 36 cm/s, and post-occlusion velocities were Vs: 19, Vm: 11.5 and Vd: 7 cm/s, with a decrease of 71%, 76% and 81%, respectively. The pulsatile index increased from 0.67 to 1.19, and the resistance index increased from 0.45 to 0.63. The other five patients without neurological deficits had mean pre-occlusion velocities of Vs: 80.4±9.9, Vm: 55.2±10.1 and Vd: 40±7.8cm/s, and post-occlusion velocities of Vs: 57.6±10.2, Vm: 48.4±10.0 and Vd: 40±7.4cm/s, with a decreased of 30±4%, 14±7% and, 1±4.7%, respectively. The pulsatile index decreased from 0.78 to 0.39 and the resistance index decreased from 0.5 to 0.31. The present results indicate that a decrease in Vm, along with a decrease in Vd, correlate well with post-occlusion neurological deficits.
