ABSTRACT
<p><b>BACKGROUND</b>In vivo proton magnetic resonance spectroscopy (MRS) provides a noninvasive method of examining a wide variety of cerebral metabolites in both healthy subjects and patients with various brain diseases. Absolute metabolite concentrations have been determined using external and internal standards with known concentrations. When an external standard is placed beside the head, variations in signal amplitudes due to B1 field inhomogeneity and static field inhomogeneity may occur. Hence an internal standard is preferable. The purpose of this study was to quantitatively analyze the metabolite concentrations in normal adult brains and gliomas by in vivo proton MRS using the fully relaxed water signal as an internal standard.</p><p><b>METHODS</b>Between January 1998 and October 2001, 28 healthy volunteers and 16 patients with gliomas were examined by in vivo proton MRS. Single-voxel spectra were acquired using the point-resolved spectroscopic pulse sequence with a 1.5 T scanner (TR/TE/Ave = 3000 ms/30 ms/64).</p><p><b>RESULTS</b>The calculated concentrations of N-acetyl-asparatate (NAA), creatine (Cre), choline (Cho), and water (H2O) in the normal hemispheric white matter were (23.59 +/- 2.62) mmol/L, (13.06 +/- 1.8) mmol/L, (4.28 +/- 0.8) mmol/L, and (47,280.96 +/- 5414.85) mmol/L, respectively. The metabolite concentrations were not necessarily uniform in different parts of the brain. The concentrations of NAA and Cre decreased in all gliomas (P < 0.001). The ratios of NAA/Cho and NAA/H2O showed a significant difference between the normal brain and gliomas, and also between the high and low grades (P < 0.001).</p><p><b>CONCLUSIONS</b>Quantitative analysis of in vivo proton MR spectra using the fully relaxed water signal as an internal standard is useful. The concentrations of NAA and the ratios of NAA/H2O and NAA/Cho conduce to discriminating between the glioma and normal brain, and also between the low-grade glioma and high-grade glioma.</p>
Subject(s)
Adult , Female , Humans , Male , Aspartic Acid , Metabolism , Brain , Metabolism , Choline , Metabolism , Creatine , Metabolism , Glioma , Metabolism , Glycine , Metabolism , Inositol , Metabolism , Magnetic Resonance SpectroscopyABSTRACT
Objective To explore the value of Multi-detector CT in spinal cord angiography. Methods Ten patients with initial MR and clinical findings suggestive of spinal cord vessel disease were performed CT spinal cord angiography.Among these,7 patients were performed DSA later within 1 week, and 4 patients were therapy by operation.CT protocol:Toshiba Aquilion 64 slice CT scanner,0.5 mm thickness,0.5/r,120 kV,350 mA,choose aortic arch level as inspection position,and use"surestart" technique with CT threshold 180 HU.Contrast medium was Iohexol(370 mg I/ml),with injection velocity of 6 ml/s.The total volume was 80 ml.The CT spinal cord angiography images were analyzed according to disease model,disease range,feeding artery,fistula,draining veins,and were compared with DSA and operation results.Results All CT spinal cord angiography images displayed spinal vessel malformation. Among these,3 patients were inner-medullary arteriovenous malformation;2 patients were peri-medullary arteriovenous fistula;5 patients were spinal dural arteriovenous fistula.All cases showed disease range,and draining veins clearly,one patient had two vessels that were false positive,and all the other cases showed feeding arteries clearly,which were confirmed by DSA.Conclusion There are great values for CT spinal angiography in diagnosing spinal vessel disease,it can be a screening exam before DSA.