OBJECTCirculating blood volume (cBV) is reported to decrease in patients who suffer a subarachnoid hemorrhage (SAH), but little is known about the correlation between changes in cBV, and patient clinical condition and time course after SAH, especially during the very acute stage. To determine appropriate management of patients with SAH, the authors measured cBV by using pulse spectrophotometry immediately after patient admission. They also evaluated whether the timing of surgery influenced changes in cBV.METHODSCirculating blood volume was measured in a total of 73 patients who were divided into the following three groups: Group A (very acute SAH) consisted of 14 SAH cases, Group B (acute SAH) included 34 SAH cases, and Group C (controls) included 25 other neurosurgical cases. All patients in Group A underwent aneurysm clipping within 6 hours after onset of SAH, whereas all patients in Group B underwent aneurysm clipping within 72 hours after onset. Hypervolemic therapy was not performed in patients with SAH. Before surgery, cBV was significantly lower in patients in Group B than in those in Group C, but there was no significant difference in this parameter when comparing Groups A and C. Although there was a transient drop in cBV in Group B patients for at least 3 days after surgery, there was no significant change in cBV in Group A patients during the study period. None of the Group A patients suffered from symptomatic vasospasm; however, four Group B patients did experience symptomatic vasospasm.CONCLUSIONSThe authors assert that normovolemic fluid management is appropriate for patients who undergo surgery during the very acute stage of SAH, whereas a relatively hypervolemic therapy is necessary for 3 to 5 days after operation to prevent early hypovolemia in patients who undergo surgery during the acute stage of SAH.

1Department of Anesthesiology, Kohnan Hospital 2Department of Neurosurgery, Anesthesiology, Tohoku University School of Medicine, Sendai, Japan

Positron emission tomography was used to investigate the metabolism of nucleic acids by18F-fluoro-2′-deoxyuridine (18F-FUdR) in 22 patients with gliomas. Sixteen cases of high grade glioma clearly demonstrated a region of high activity with a differential absorption rate (DAR) of 0.64 ± 0.34. Six cases of low grade glioma failed to reveal a positive image of the tumor and the DAR in tumor was 0.21 ± 0.042 (p < 0.01). This PET-18F-FUdR study succeeded in differentiating high and low grade gliomas from the view point of nucleic acid metabolism.

Two cases with C2 segmental type of vertebral artery (VA) were reported. One case was a 64-year-old man, who was referred to our hospital suffering from vertigo, ataxia, and right facial palsy. Computed tomography (CT) scan showed multiple lacunae in the basal ganglia bilaterally. Another case was a 47-year-old man, complaining of left hemiparesthesia. A small high density area with a little enhancement was seen in the right parietal region in CT scan, and the lesion was diagnosed as cavernous angioma. Angiography of both cases depicted the vertebral artery not passing through the transverse foramen of the Atlas, but running medioposterior to it, and magnetic resonance imaging (MRI) and CT findings showed the vertebral artery running between the Atlas and Axis, and entering into the spinal canal. In our experience of 1669 sides in 1436 cases, such anomaly of the vertebral artery was found in ten cases including the two abovementioned. Six cases of such anomaly have previously been reported, but demonstration of the VA coursing between Atlas and Axis by MRI has not been published in the literature. During surgical therapy on the upper cervical spine, especially when using a posterior approach, or C1-C2 lateral puncture, the possibility of an anomalous vertebral artery, as in our cases, should be taken into consideration.

Using positron emission tomography and radio-high performance liquid chromatography, the accumulation of 2′-deoxy-5-18F-fluorouridine in the brain tumors and plasma pharmacokinetic parameters were investigated in 20 patients. High accumulation of the tracer in high grade gliomas and meningiomas and very rapid degradation of the tracer in the plasma were found. Very large variations were observed in both tumor accumulation and pharmacokinetic data. The tumor accumulation, however, did not correlate with any of the plasma pharmacokinetic parameters: area under the plasma concentration-time curve, mean residence time, total body clearance and steady-state volume of distribution. The results suggest that the accumulation of the tracer reflects the metabolic activity of the brain tumor tissues and that the effect of the rapid metabolic change in the tracer in the plasma on the tumor accumulation may be minor.

In order to evaluate the methionine uptake of a glioma with positron emission tomography (PET), the kinetics of carbon-11 methionine was investigated in 11 patients by measuring the free 11C-methionine in plasma as an input function following intravenous administration. When the mean clearance curve of free 11C-methionine in plasma instead of individual 11C-methionine clearance curves was used, mean differences in uptake rate and distribution volume were 4.0% and 4.6% respectively. By applying the mean clearance curve of free 11C-methionine in 18 glioma patients, significant differences in 11C-methionine uptake rate and distribution volume were found according to pathological grading. For the accurate evaluation of the metabolism of 11C-methionine, it is therefore preferable that the actual level of free 11C-methionine in the plasma be measured, especially for the follow-up of individual cases. The study also demonstrated that the mean clearance curve of 11C-methionine in plasma might be employed as an input curve for calculating the uptake rate and distribution volume with small errors.

To shed light on the metabolic changes in glioma following therapy, uptake changes among 18F-fluoro-2′-deoxyuridine (18FUdR), 14C-thymidine (dThd),14C-methionine (Met) and 3H-deoxyglucose (DG) in glioma model after chemotherapy were studied, as a means for interpreting clinical PET results, together with the changes in the bromodeoxyuridine (BUdR) labeling index. 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(-2 chloroethyl)-3-nitrosourea hydrochloride (ACNU) was administered intraperitoneally in the tumor-bearing rats and uptake of the tracers or BUdR labeling index in tumor tissue were measured. The metabolic response following chemotherapy was a sharp fall immediately for 14C-dThd and 18FUdR and a moderate fall for 14C-Met whereas there was a fall in 3H-DG from 1 week after chemotherapy. The changes of BUdR labeling index paralleled that in the uptake for dThd and FUdR. These result indicate that PET scans using a variety of tracers in conjunction could be used for clinical diagnosis and evaluation of therapy in glioma cases. 18FUdR is a promising tracer of nucleic acid metabolism to evaluate the proliferative potential of brain gliomas.

Positron emission tomography (PET) has been widely used in the diagnosis of brain tumors and in the evaluation of therapy. 18F-fiuorodeoxyglucose (18FDG) and 11C-methionine have been used to diagnose the malignancy of tumors and to evaluate therapeutic effectiveness [1–3]. Moreover, tracers indicating the metabolism of nucleic acid have been investigated and 18F-fluoro-2′-deoxyuridine (18FdUrd) was developed for this use [4–8]. To shed light on the metabolic changes in gliomas following therapy, we have used a glioma model to study correlational changes among 18FdUrd, 14C-thymidine, 14C-methionine, and 3H-deoxyglucose uptake after chemotherapy as a means for interpreting clinical PET results, together with the changes in the bromodeoxyuridine labeling index (BUdR LI).

The metabolic fate of 2′-deoxy-5-[18F]fluorouridine ([18F]FdUrd), a useful positron emission tomography (PET) tracer of nucleic acid metabolism in tumors, was investigated in mice and humans. A rapid increase in labeled catabolites was found in mouse and human plasma. In mouse FM3A mammary carcinoma, the corresponding catabolites were also detected in addition to metabolites which were activated by the nucleic acid metabolism. From a biodistribution study of β-[3H]alanine, α-[18F]fluoro-β-alanine, a major catabolite, was assumed to be taken up twice as much by tumor than by the brain. Nucleic acid metabolism in brain tumors by [18F]FdUrd-PET may be assessed using normal brain regions as a reference.

Fourteen patients with cerebral gliomas were studied with positron emission tomography (PET) using L-[methyl-11C]methionine (11C-MET). Positive images of tumour were obtained in all cases regardless of histological grades. The analysis of differential absorption ratio (DAR) showed the higher accumulation of 11C-MET in high grade gliomas than in low grade gliomas. PET study with 11C-MET will be of great value not only in delineating the location of gliomas, but also in making a qualitative diagnosis from the view point of the biological properties of gliomas.