Role of thymoglobulin in matched sibling allogeneic hematopoietic stem cell transplantation with busulfan and fludarabine conditioning in myeloid malignanicies.

In vivo T-cell depletion using anti-thymocyte globulin (ATG) is widely used in allogeneic hematopoietic stem cell transplantation (HSCT) for prophylaxis of GvHD. We investigated the influence of thymoglobulin dose (an ATG) on GvHD following matched sibling donor (MSD) HSCT with a busulfan and fludarabine preparative regimen. Medical records of 180 patients who received MSD HSCT with a conditioning regimen of busulfan, fludarabine, and ATG (BuFluATG) were reviewed retrospectively. The median age was 53 years (range 18-68). Initial diagnoses were acute myeloid leukemia (73.3%) and myelodysplastic syndrome (26.7%). Forty-four and 68 patients (24.4 and 37.7%) experienced acute and chronic GvHD of any grade, respectively. High-dose (⩾4.5 mg/kg) ATG was independently associated with decreased risk of acute GvHD (hazard ratio=0.36, 95% confidence interval (CI): 0.15-0.84, P=0.019) compared to low-dose ATG (<4.5 mg/kg). Although ATG dose was associated with the risk of acute GvHD, it was not associated with the risk of chronic GvHD in our study. A higher dose (⩾4.5 mg/kg) of ATG decreases the risk of acute GvHD but had no significant impact on disease-free survival in MSD HSCT patients conditioned with BuFluATG. The optimal dose of ATG should be further investigated in a large prospective study context.

Sunitinib (SUTENT, SU11248) suppresses tumor growth and induces apoptosis in xenograft models of human hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the fifth most common and third deadliest primary neoplasm. Since HCC is a particularly vascular solid tumor, we determined the antitumor and antiangiogenic activities of sunitinib malate, a potent inhibitor of two receptors involved in angiogenesis - vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR). In the present study, we reported that treatment of HepG2 and SK-Hep-1 cells with sunitinib led to growth inhibition and apoptosis in a dose-dependent fashion. Sunitinib inhibited phosphorylation of VEGFR-2 at Tyr951 and PDGFR-beta at Tyr1021 both in vitro and in vivo. Sunitinib also suppressed tumor growth of five patient-derived xenografts. Sunitinib-induced tumor growth inhibition was associated with increased apoptosis, reduced microvessel density and inhibition of cell proliferation. This study provides a strong rationale for further clinical investigation of sunitinib in patients with hepatocellular carcinoma.

2-[18F]-2-deoxy-D-glucose (FDG) uptake in human tumor cells is related to the expression of GLUT-1 and hexokinase II.

BACKGROUND: The uptake of 2-[18F]-2-deoxy-D-glucose ((18)F-FDG) is widely used as a marker of increased glucose metabolism to monitor progression of cancers with positron emission tomography (PET). Many tumors have been shown to overexpress facilitated glucose transporters, especially GLUT-1 and a glycolytic enzyme, hexokinase II. PURPOSE: To define whether a quantitative relationship exists between the expression levels of GLUT-1 and hexokinase II, and (18)F-FDG uptake in human cancer xenografts. MATERIAL AND METHODS: We determined the expression levels of both GLUT-1 and hexokinase II in normal cells and in five different human cancer cell lines (AGS, A431, A549, Colo 320 HSR, and HepG2) using Western blot analysis. In vitro assays of 18F-FDG uptake in cultures were performed, and subsequently representative cell lines were inoculated onto the flanks of severe combined immunodeficient (SCID) mice. To establish an orthotopic model of human hepatocellular carcinoma (HCC), cells were injected into the intraportal vein of SCID mice. (18)F-FDG uptake in vivo was assessed by subjecting mice to PET imaging. RESULTS: All cell lines were shown to express higher amounts of GLUT-1 and hexokinase II compared with fibroblast controls. Our results from in vitro (18)F-FDG uptake assays also correlated with the Western blot results. All xenografts gave highly positive results at microPET imaging, and a strong correlation (R(2)=0.88, P<0.001) was found between the maximum standardized uptake values (SUV(max)) and the expression of GLUT-1 proteins. CONCLUSION: Our data indicate that the expression levels of GLUT-1 and hexokinase II as well as in vitro assays of FDG uptake serve as good screening tests to evaluate the feasibility of cell lines to be further developed into xenograft cancer models for small-animal PET imaging.

In vitro evaluation of fibrin mat and Tegaderm wound dressing for the delivery of keratinocytes--implications of their use to treat burns.

The effectiveness of fibrin mat and Tegaderm delivery systems to maintain clonogenic keratinocytes in culture were evaluated using in vitro methods. A fibrin mat was found to provide a culture environment that is conducive for the proliferation of keratinocytes and supporting their ability to form colonies of good growth potential in vitro. This confirms that the fibrin mat is a good delivery system for cultured epithelial autograft (CEA). In our unit, fibrin-CEA is limited only for the treatment of severe burns due to the high cost of fibrin glue. However, this substrate is able to maintain the regenerative properties of the CEA which is crucial for the treatment of extensive and full thickness burns. Tegaderm, a cost-effective polyurethane wound dressing is able to support keratinocyte cell growth but at a slower rate and with fewer colonies formed compared to the fibrin system. This suggests that Tegaderm can be an alternative approach of delivering autologous cells, limited to treat chronic wounds and less extensive burns. The use of simple and relatively inexpensive bench techniques can potentially serve as a quality control to check for keratinocytes cultured and delivered to every patient in the clinical setting.

Reversed discrepancy between CT and diffusion-weighted MR imaging in acute ischemic stroke.

PURPOSE: We sought to determine whether an early CT ischemic lesion showing parenchymal hypoattenuation might be undetectable on diffusion-weighted imaging (DWI) in acute cerebral ischemia. MATERIALS AND METHODS: We retrospectively evaluated CT and MR images of 70 consecutive patients with acute middle cerebral artery (MCA) infarction. All patients underwent CT and MR imaging within 6 hours of symptom onset. We determined the presence of reversed discrepancy (RD), defined as an early ischemic lesion showing parenchymal hypoattenuation on CT but no hyperintensity on DWI. CT Hounsfield units (HU), apparent diffusion coefficients (ADCs), and perfusion parameters were calculated for RD lesions. RESULTS: RD was found in 9 (12.9%) patients and at basal ganglia (89%). The mean HU of RD lesion was lower than that of normal tissue (DeltaHU, 2.33 +/- 0.74, P < .001). RD lesions showed no significant decrease of ADC (ADC ratio, 0.97 +/- 0.07, P = .059) and cerebral blood flow (relative CBF, 0.87 +/- 0.20, P > 0.05). Delayed DWI hyperintensity occurred in 8 (88.8%) RD lesions, and all lesions progressed to infarction. In 6 (66%) of 9 patients with RD, Alberto Stroke Program Early CT scores of ischemic lesions were lower on CT than those on DWI. CONCLUSION: RD was uncommonly found mainly in basal ganglia, and all RD lesions progressed to infarction at follow-up. Early CT ischemic lesion showing parenchymal hypoattenuation may be undetectable on DWI, and DWI may underestimate extent of severe ischemic tissue in patients with acute MCA infarction.

3T 1H-MR spectroscopy in grading of cerebral gliomas: comparison of short and intermediate echo time sequences.

BACKGROUND AND PURPOSE: Echo time (TE) can have a large influence on the spectra in proton MR spectroscopy ((1)H-MR spectroscopy). The purpose of this study was to comparatively assess the diagnostic value of 3T single-voxel (1)H-MR spectroscopy with short or intermediate TEs in grading cerebral gliomas. METHODS: Single voxel (1)H-MR spectroscopy was performed at 3T in 35 patients with cerebral glioma. The spectra were obtained with both short (35 ms) and intermediate TEs (144 ms). Metabolite ratios of choline (Cho)/creatine (Cr), Cho/N-acetylaspartate (NAA), lipid and lactate (LL)/Cr and myo-inositol (mIns)/Cr were calculated and compared between short and intermediate TEs in each grade. After receiver operating characteristic curve analysis, diagnostic accuracy for each TE in differentiating high-grade glioma from low-grade glioma was compared. RESULTS: At short TE, Cho/Cr and Cho/NAA ratios were significantly lower, and LL/Cr and mIns/Cr were significantly higher, compared with those at intermediate TE, regardless of tumor grade. Lactate inversion at intermediate TE was found in only 2 patients. At both TEs, there were significant differences in Cho/Cr and LL/Cr ratios between low- and high-grade gliomas. Diagnostic accuracy was slightly higher at short TE alone or combined with intermediate TE than intermediate TE alone (85.7% versus 82.9%). CONCLUSION: Metabolite ratios were significantly different between short and intermediate TE. Cho/Cr and LL/Cr ratios at either TE were similarly useful in differentiating high-grade gliomas from low-grade gliomas. If only a single spectroscopic sequence can be acquired, short TE seems preferable because of poor lactate inversion at intermediate TE on 3T single-voxel (1)H-MR spectroscopy.

Effect of seizure on hippocampus in mesial temporal lobe epilepsy and neocortical epilepsy: an MRS study.

This study was performed to evaluate the effect of seizures on the bilateral hippocampus in mesial temporal lobe epilepsy (mTLE) and neocortical epilepsy by single voxel proton magnetic resonance spectroscopy (MRS). Forty-one patients with mTLE having unilateral hippocampal sclerosis and 43 patients with a neocortical epilepsy who underwent subsequent epilepsy surgery were recruited. Ninety-five percent confidence intervals of N-acetyl aspartate/choline (NAA/Cho) and NAA/creatine (NAA/Cr) ratios in 20 healthy control subjects were used as threshold values to determine abnormal NAA/Cho and NAA/Cr. NAA/Cho and NAA/Cr were significantly lower in the ipsilateral hippocampus of mTLE and neocortical epilepsy. Using asymmetry indices for patients with bilaterally abnormal ratios of NAA/Cho and NAA/Cr in addition to using unilateral abnormal ratio, the seizure focus was correctly lateralized in 65.9% of patients with mTLE and 48.8% of neocortical epilepsy patients. Bilateral NAA/Cho abnormality was significantly related to a poor surgical outcome in mTLE. No significant relationship was found between the results of NAA/Cho or NAA/Cr and surgical outcome in neocortical epilepsy. The mean contralateral NAA/Cr ratio of the hippocampus in mTLE was significantly lower in patients with a history of secondary generalized tonic-clonic seizure (SGTCS) than in those without. Our results demonstrate effects of seizures on the hippocampi in neocortical epilepsy and the relation between SGTCS and NAA/Cr of the contralateral hippocampus in mTLE. This proves the presence of a seizure effect on the hippocampus in neocortical epilepsy as well as in mTLE.

Flap prefabrication - the bridge between conventional flaps and tissue-engineered flaps.

Flap prefabrication is one of the most exciting areas in Plastic Surgery because of its bridging role between conventional reconstructive surgery and tissue engineering. Using this technique,tissues such as bone, cartilage, skin and muscle can be preassembled to form precise composites that will fit any defect. In pre-lamination, for example, an ear may be created by burying cartilage underneath forearm skin and later harvested as a skin-cartilage composite free flap to replace the missing part. Vascular induction is yet another means of customising flaps where new blood supply is introduced to create transplantable tissue. For example, bone chips wrapped in avascular carrier such as muscle can become vascularised grafts. Our experiment describes jejunal prefabrication in a rat model using the same technique. Intestinal segments wrapped in muscle flaps become independent of their mesenteric blood supply by "parasitising" on the muscle's blood supply. This idea arose from our initial observations that intestinal segments transferred to the neck to reconstruct the oesophagus could survive accidental disruption of the pedicle if sufficient time had elapsed. Clearly, the bowel had picked up new blood supply from its bed. Subsequently, jejunal prefabrication was used to reconstruct the oesophagus in a patient in whom there were no recipient vessels for free jejunal transfer. The pedicled latissimus dorsi muscle flap was used as a carrier for the jejunum. Another application of this idea could be in the area of allogeneic trachea or pancreatic transplantation, since present-day techniques have yet to overcome problems such as insufficient vascularity and unpredictable transplant survival. Future applications incorporating biomaterials and cultured cells will usher in the era of tissue-engineered flaps.

Limited utility of interictal apparent diffusion coefficient in the evaluation of hippocampal sclerosis.

OBJECTIVE: Quantitative measurement of diffusion has been studied as an independent parameter for the identification and characterization of abnormal hippocampi and temporal lobes in epileptic patients. MATERIAL AND METHODS: In order to study the diagnostic value of magnetic resonance diffusion weighted imaging (DWI) and the apparent diffusion coefficient (ADC) from the temporal region, interictal DWI and ADC values were prospectively obtained from both hippocampal areas and temporal lobes bilaterally and compared between 19 normal volunteers and 20 medial temporal lobe epilepsy (MTLE) patients. RESULTS: In all patients, visual assessment of DWI failed to lateralize the lesion. However, the overall correct lateralization rate of interictal ADC was 100% (20/20) if the side with the higher ADC value was considered to be abnormal. Comparison of the MTLE lesion side values with those of the normal volunteers revealed that the ADC values measured from the hippocampal areas and temporal lobes of the MTLE patients were significantly higher than those from the normal volunteers on the lesion side (P < 0.05) and also on the contralateral side although not statistically significant. The absolute differences between the ADC values of the higher and lower side, in both the hippocampus and the temporal lobe, were not significant among the normal volunteers and the MTLE patients. CONCLUSION: Although the correct lateralization rate of interictal ADC in the MTLE patients was 100%, the application of elevated ADC value as a diagnostic criteria for MTLE was disappointing because such elevation in ADC values was not limited only to the ipsilateral temporal region but also in the contralateral side in MTLE.

2-octylcyanoacrylate-assisted microvascular anastomosis: comparison with a conventional suture technique in rat femoral arteries.

Standard microvascular anastomosis using only sutures is a well-established and successful technique; however, it is time-consuming and may cause vessel narrowing, needle trauma, and tissue reaction. The authors' hypothesis was that 2-octylcyanoacrylate could simplify microvascular anastomosis and reduce wall trauma and reaction. End-to-end anastomoses of the femoral arteries were performed in 20 adult rats. Each animal served as its own control. The time taken for each anastomosis (from first stitch to release of clamps) was noted, and the patency assessed. At day 7, the anastomoses were reassessed for patency, and the vessels evaluated histologically. 2-octylcyanoacrylate reduced the need to insert more sutures. Anastomotic time in the study group was statistically significantly shorter (p < 0.001), and the patency rate was 90 percent, compared to 85 percent with the standard suture technique. There was also less intense inflammatory reaction, with fewer foreign-body granulomata. This is the first report on the use of 2-octylcyanocrylate, currently approved for cutaneous use, for vessel anastomosis. Further work on the biomechanics and long-term histologic effects will be carried out. 2-octylcyanoacrylate has the potential for simplifying and improving the patency rates of arterial microanastomosis.

Lateralizing ability of single-voxel proton mr spectroscopy in hippocampal sclerosis: comparison with mr imaging and positron emission tomography.

BACKGROUND AND PURPOSE: Proton MR spectroscopy (MRS) is still in the early stages in the evaluation of epilepsy, and comparisons with MR imaging and positron emission tomography (PET) in the same patients have rarely been documented. The purpose of this study was to evaluate the lateralizing ability of single-voxel MRS in comparison with MR imaging and PET in patients with hippocampal sclerosis. METHODS: Thirty-three patients with intractable temporal lobe epilepsy whose MR imaging diagnosis was unilateral hippocampal sclerosis and who underwent anterior temporal lobectomy and had good postsurgical outcome over 1-year follow-up were included in the study. MR spectra were obtained from the hippocampus bilaterally, using the point-resolved spectroscopy sequence. Metabolite ratios of NAA/Cho and NAA/Cr were calculated from the relative peak height measurements. An NAA/Cho ratio of 0.8 or less and an NAA/Cr ratio of 1.0 or less were regarded as abnormal. The MRS results were compared retrospectively with those of MR imaging and PET as to the ability to lateralize the epileptogenic focus. RESULTS: The sensitivity of MRS and PET (concordance with MR imaging) was 85% each in the lateralization of the ipsilateral lesion side. Bilateral abnormalities were seen in 30% of the patients. False-lateralization rates for MRS and PET were 3% and 6%, respectively. The concordance rate of MRS and PET was 73%, when comparing the results of the ipsilateral lesion side. CONCLUSION: MRS may be used as an adjunct tool in the evaluation of hippocampal sclerosis, like PET, although its sensitivity has to be improved and the clinical significance of bilateral abnormality is still to be determined.

Diffusion-weighted MR imaging in biopsy-proven Creutzfeldt-Jakob disease.

OBJECTIVE: To compare conventional and diffusion-weighted MR imaging in terms of their depiction of the abnormalities occurring in Creutzfeldt-Jakob disease. MATERIALS AND METHODS: We retrospectively analyzed the findings of conventional (T2-weighted and fluid-attenuated inversion recovery) and diffusion-weighted MR imaging in four patients with biopsy-proven Creutzfeldt-Jakob disease. The signal intensity of the lesion was classified by visual assessment as markedly high, slightly high, or isointense, relative to normal brain parenchyma. RESULTS: Both conventional and diffusion-weighted MR images demonstrated bilateral high signal intensity in the basal ganglia in all four patients. Cortical lesions were observed on diffusion-weighted MR images in all four, and on fluid-attenuated inversion recovery MR images in one, but in no patient on T2-weighted images. Conventional MR images showed slightly high signal intensity in all lesions, while diffusion-weighted images showed markedly high signal intensity in most. CONCLUSION: Diffusion-weighted MR imaging is more sensitive than its conventional counterpart in the depiction of Creutzfeldt-Jakob disease, and permits better detection of the lesion in both the cerebral cortices and basal ganglia.

Diffusion-weighted MRI in cystic or necrotic intracranial lesions.

Our purpose was to investigate the signal intensities of cystic or necrotic intracranial lesions on diffusion-weighted MRI (DWI) and measure their apparent diffusion coefficients (ADC). We examined 39 cystic or necrotic intracranial lesions in 33 consecutive patients: five malignant gliomas, seven metastases, two other necrotic tumours, a haemangioblastoma, three epidermoids, an arachnoid cyst, seven pyogenic abscesses, 12 cases of cysticercosis and one of radiation necrosis. DWI was performed on a 1.5 T unit using a single-shot echo-planar spin-echo pulse sequence with b 1,000 s/mm2. The signal intensity of the cystic or necrotic portion on DWI was classified by visual assessment as markedly low (as low as cerebrospinal fluid), slightly lower than, isointense with, and slightly or markedly higher than normal brain parenchyma. ADC were calculated in 31 lesions using a linear estimation method with measurements from b of 0 and 1,000 s/ mm2. The cystic or necrotic portions of all neoplasms (other than two metastases) gave slightly or markedly low signal, with ADC of more than 2.60 x 10(-3) mm2/s. Two metastases in two patients showed marked high signal, with ADC of 0.50 x 10(-3) mm2/s and 1.23 x 10(-3) mm2/s, respectively. Epidermoids showed slight or marked high signal, with ADC of less than 1.03 x 10(-3) mm2/s. The arachnoid cyst gave markedly low signal, with ADC of 3.00 x 10(-3) mm2/s. All abscesses showed marked high signal, with ADC below 0.95 x 10(-3) mm2/s. The cases of cysticercosis showed variable signal intensity; markedly low in five, slightly low in three and markedly high in four.

Implantation of a nerve ending into a vein.

Neuromas can be painful and physically and psychologically disabling. Among the many methods of treatment available, translocation away from noxious stimuli, such as implantation in muscle or bone, has been used. Veins are easily available and accessible to nerves. The outcome of a nerve ending implanted into a vein and the effects of the implanted nerve on the vein have not been studied. This study evaluated neuroma prevention with a new technique that involves implanting a nerve ending into a vein. The medial branches of the right femoral nerve of 20 rats were transected at midthigh level. The distal segments were excised. The proximal segments were implanted into the femoral vein. The epineurium was sutured to the tunica adventitia using interrupted 10-0 Ethilon sutures. The left side served as controls where the proximal nerve stumps were left lying in their beds. The animals were sacrificed 12 weeks after the operation. Histologic analysis of 12 controls showed neuromas. Twelve implanted nerves showed neuromas that were smaller than those of the controls. The difference was statistically significant. The regenerated nerve fibers were found within the adventitia and muscular wall of the vein. There was no extension of nerve tissue into the vessel lumen and no thrombosis of the vein. Electron microscopic study on the other eight rats showed abnormal large myelinated fibers in the controls and in the implanted nerves. The fibers in the implanted group were degenerated.

Changes in prostaglandin and nitric oxide levels in the hyperdynamic circulation following liver resection.

BACKGROUND AND AIMS: Significant changes in hepatic haemodynamics occur after major hepatectomy, but the pathogenesis of this phenomenon is unclear. This study investigates the serum profile of prostaglandin and nitric oxide in the hepatic and systemic circulation before and after hepatectomy and the temporal relationship of these to changes in the hepatic blood flow. METHODS: Blood samples were collected from the internal jugular, portal and hepatic veins of six Yorkshire pigs (17-25 kg) before, immediately after and 48 h after partial hepatectomy. RESULTS: Serum levels of prostacyclin I2 (PGI2) and prostaglandin E2 (PGE2) from the systemic circulation, the portal circulation and from the hepatic veins were found to differ considerably even before hepatectomy. After the hepatectomy was performed, there was a significant rise in PGI2 levels in the systemic circulation (P=0.027). Hepatic blood flow and cardiac output were measured before hepatectomy, 24 and 48 h after hepatectomy in another six pigs. A significant increase in hepatic blood flow (P=0.029) occurred after the hepatectomy and this was accompanied by a concomitant increase in the cardiac output (P=0.042). The increase in PGI2 concentration in the systemic circulation after hepatectomy appears to accompany the development of hyperdynamic hepatic and systemic circulations. No significant change was found in circulating PGE2 levels in the systemic, portal and hepatic veins at the three collection intervals (i.e. pre, post and 48 h after hepatectomy). The PGE2 levels in the hepatic vein, however, were significantly higher from than in the portal vein (P=0.028). No significant changes were observed in the level of nitric oxide. CONCLUSION: This study demonstrates an increase in the total hepatic blood flow after hepatectomy together with a threefold increase in prostacyclin in the systemic circulation. The liver was identified as the main source of circulatory prostaglandin.

Diffusion-weighted imaging in Wallerian degeneration.

We report two patients displaying hyperintensities on diffusion-weighted imaging (DWI) in the area of Wallerian degeneration (WD) at 12 days after stroke. High signal intensities were more conspicuous on DWI than on T2-weighted images. Both patients showed decreased diffusion anisotropy resulting in elevated apparent diffusion coefficient in the area of WD. These patients illustrate that DWI may be useful in the detection of the early stage of WD.

Neuronal metabolic changes in the cortical region after subcortical infarction: a proton MR spectroscopy study.

OBJECTIVES: To investigate whether proton magnetic resonance spectroscopy ((1)H MRS) can detect neuronal metabolic changes in the cortical region in patients with cortical dysfunction after subcortical infarction. METHODS: Fifteen patients with subcortical large (diameter>/=20 mm) infarcts were studied; nine patients with cortical dysfunction (group A), and six without (group B). Seven patients with lacunar infarction served as controls. Infarct volume was measured on T2 weighted images with an image analyser. (1)H MRS data were obtained in three regions; high signal intensity area on T2 weighted image, overlying cortex with a normal T2 MRI appearance, and contralateral homologous cortical region. RESULTS: Infarct volume was not different between groups A and B. N-acetylaspartate (NAA)/creatine+phosphocreatine (Cr) ratios in the cortical region overlying subcortical infarcts in group A were significantly lower than those in group B and the control group (p=0.002). The NAA/Cr ratios in the overlying cortex were significantly lower than those in the contralateral normal cortex in group A on the initial (p=0. 015) and follow up (p=0.028) (1)H MRS, but these differences were not found in group B and the control group. CONCLUSIONS: The results support the idea that the cerebral cortex is a responsible location for cortical dysfunction after subcortical infarctions. (1)H MRS can be used as a sensitive method for the detection of a neuronal metabolic damage, which is not demonstrated by conventional MRI.

In vivo proton magnetic resonance spectroscopy of central neurocytomas.

OBJECTIVE: The authors report on the metabolic features of central neurocytomas observed during in vivo single-voxel proton magnetic resonance spectroscopy. METHODS: Volume-selective single-voxel proton magnetic resonance spectroscopy was performed with a 1.5-T unit using a point-resolved spectroscopy sequence (TR/TE = 2000 ms/135 and 270 ms) to obtain spectra of a single 8-cc voxel. The subjects were five patients in the Department of Neurosurgery of Seoul National University Hospital whose central neurocytomas had been diagnosed histologically. The peak intensities of compounds containing choline (Cho), N-acetylaspartate, creatine/phosphocreatine, and lactate were analyzed. RESULTS: The ratios of Cho to creatine/phosphocreatine and Cho to N-acetylaspartate were significantly higher than ratios in normal brains. A lactate signal was present, and an unidentified signal was also observed at 3.55 ppm, which might have been produced by inositol or glycine. CONCLUSION: A combination of the signal at 3.55 ppm and a prominent Cho peak seems to be a characteristic feature of central neurocytomas. Volume-selective single-voxel proton magnetic resonance spectroscopy could provide additional information to aid in diagnosing this condition.