Blood Flow and Metabolism of Oligodendrogliomas: A Positron Emission Tomography Study with Kinetic Analysis of 18F-fluorodeoxyglucose

To accurately characterize the pathophysiology and proliferating activity of oligodendrogliomas, we studied cerebral blood flow and metabolism using positron emission tomography (PET) in five patients with this tumor. Regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen extraction fraction (rOEF), and cerebral metabolic rates of oxygen (rCMRO₂) and of glucose (rCMRGl) were quantitatively measured in tumor lesions and the contralateral gray matter. rCMRGl was analyzed based on both kinetic and autoradiographic methods. Tumor rCBF and rCBV were lower than in the contralateral gray matter in all preoperatively examined patients. Oxygen metabolism, determined by rCMRO₂ and rOEF, was consistently reduced in the tumor (rCMRO₂, P<0.05 vs. gray matter, determined by the Student's t-test). Tumor rCMRGl was significantly lower than the gray matter rCMRGl in both kinetic (P<0.01) and autoradiographic (P<0.05) analyses. Kinetic tumor rCMRGl varied between 1.22 and 4.13mg/100ml/min, but was lower than the gray matter value in all patients. Autoradiographic tumor rCMRGl, which ranged from 1.02 to 5.79mg/100ml/min, was also reduced in all tumors but one; the remaining tumor, which had a relatively high value of autoradiographic rCMRGl (comparable to gray matter rCMRGl), infiltrated the contralateral hemisphere through the corpus callosum, and was characterized by high cellular density. In one patient who suffered from tumor recurrence 8 years and 10 months after initial treatment, phosphorylation constant (K3) and kinetic rCMRGl of the recurring tumor were higher than those of the original tumor. No other tumors have regrown or recurred during the postoperative follow-up periods, which ranged from 22 to 130 months (median=101 months). Circulation and metabolism measured by PET provide in vivo biological characteristics, including proliferating activity, in oligodendrogliomas.     

Cerebellopontine angle xanthogranuloma: report of a surgical case

A Case of xanthogranuloma at the cerebellopontine angle is reported here in detail with a review of the literature. A 36-year-old male suffered from tinnitus and hearing disturbance for five months before admission. View of the internal auditory canal showed widening and destruction on the right side. Auditory brain stem response did not clarify any of wave. A slight high density area was revealed by CT with some degree of enhancement. A right paramedian suboccipital craniectomy revealed an encapsulated tumor at the right cerebellopontine angle extending into the internal auditory canal. The tumor was reddish-brown, creamy and 2 cm in diameter, which was totally extirpated. Twenty two days after the operation, the patient was discharged with a slight improvement of the right tinnitus. Seventeen surgical cases of intracranial xanthogranuloma were reviewed including the presented case. There were 10 males and seven females, and the age ranged from six to 57 years. Many of them were located in the choroid plexus or the dura mater. The presented case was the first reported one documenting a xanthogranuloma at the cerebellopontine angle. A solitary lesion was seen in 13 cases, and multiple lesions in four cases, among which Hand-Schüller-Christian disease was observed in two, and Weber-Christian disease in one. A high density area was revealed in eight out of nine cases, and some degree of enhancement was seen in nine. Surgical removal was performed totally in nine cases, subtotally in six, and partially in one. The outcome was excellent in eight cases, good in three, fair in one, poor in two, and dead in three.     

Environmental enrichment stimulates progenitor cell proliferation in the amygdala

Enriched environments enhance hippocampal neurogenesis, synaptic efficacy, and learning and memory functions. Recent studies have demonstrated that enriched environments can restore learning behavior and long‐term memory after significant brain atrophy and neural loss. Emotional and anxiety‐related behaviors were also improved by enriched stimuli, but the effect of enriched environments on the amygdala, one of the major emotion‐related structures in the central nervous system, remains largely unknown. In this study, we have focused on the effects of an enriched environment on cell proliferation and differentiation in the murine amygdala. The enriched environment increased bromodeoxyuridine (BrdU)‐positive (newborn) cell numbers in the amygdala, almost all of which, immediately after a 1‐week period of enrichment, expressed the oligodendrocyte progenitor marker Olig2. Furthermore, enriched stimuli significantly suppressed cell death in the amygdala. Some of the BrdU‐positive cells in mice exposed to the enriched environment, but none in animals housed in the standard environment, later differentiated into astrocytes. Our findings, taken together with previous behavioral studies, suggest that progenitor proliferation and differentiation in the amygdala may contribute to the beneficial aspects of environmental enrichment such as anxiolytic effects. © 2009 Wiley‐Liss, Inc.     

Analysis of regional blood flow, blood volume, oxygen and glucose metabolism in heterogeneous parts of untreated high grade gliomas using positron emission tomography (PET)

A high resolution positron emission tomography (PET), HEADTOME III, has enabled us to visualize heterogeneous parts, i.e. viable, necrotic, and edematous portions in malignant gliomas, and to quantify regional hemocirculation and metabolism of the tumors using 15O and 18F-fluorodeoxyglucose tracers. Hemocirculatory and metabolic indices of regional cerebral blood flow (rCBF), blood volume (rCBV), oxygen extraction fraction (rOEF), oxygen consumption (rCMRO2) and glucose consumption (rCMRGl) were studied in eight patients with untreated malignant gliomas. Regions of interest (ROIs) in PET images were focused on lesions corresponding to contrast enhancing areas, central low density areas of the tumors, and peritumoral low density areas in CT scans. In the viable portion of the gliomas, rCBV (5.20 +/- 1.18ml/100ml, mean +/- SD, n = 8) was significantly higher than that of the contralateral gray matter (p less than 0.05), which is suggestive of high vascularity; rOEF (0.36 +/- 0.16) and rCMRO2 (1.66 +/- 0.45ml/100ml/min) values markedly decreased (p less than 0.05, p less than 0.01). On the other hand, rCBF (36.3 +/- 13.0ml/100ml/min) and rCMRGl (5.94 +/- 1.15mg/100ml/min) were similar to that of the contralateral gray matter. A relative dissociation between oxygen and glucose metabolism indicates anaerobic glycolysis in the energy metabolism of malignant gliomas. In the central low density area, rCBF, rCBV, rOEF, rCMRO2, rCMRGl values decreased significantly from the viable portion and the contralateral gray matter. rOEF was markedly reduced in the central low density area as compared with that of the peritumoral low density area. The rOEF reduction indicates that oxygen metabolism of gliomas is the first to fail, accompanied by autoregulatory impairment of vessels.(ABSTRACT TRUNCATED AT 250 WORDS)     

In vivo measurements of regional cerebral hemocirculation and metabolism in gliomas using 15O and 18F-fluorodeoxyglucose positron emission tomography

A high resolution PET-HEADTOME III has been employed to quantitate regional cerebral hemodynamics and metabolism in gliomas using O-15 and 18FDG tracers, and to evaluate histological malignancy preoperatively. Hemodynamic and metabolic indices of regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen consumption (rCMRO2), oxygen extraction (rOEF), and glucose consumption (rCMRGl) were studied on thirteen preoperative gliomas involving one recurrent case. Regions of interest (ROIs) on PET were placed over the corresponding lesions in CT scans. In high grade gliomas, ROIs were also focused on the corresponding parts of central low density area, contrast enhanced area, and peritumoral low density area. rCBF and rCBV were variable and unrelated in both low and high grade gliomas. rCMRGl values were 5.99 +/- 3.99 mg/100 ml/min for high grade gliomas, and 3.01 +/- 0.48 mg/100 ml/min for low grade gliomas. Lesions with high uptake of radioisotope were proved to be high grade gliomas. lesions with low uptake being low grade gliomas. In comparison with the contralateral gray matter around the sylvian fissure, rCBV was significantly higher(p less than 0.02) in high grade gliomas, and rCMRGl was lower (p less than 0.05) in low grade gliomas. rCMRO2 and rOEF values were reduced markedly (p less than 0.01) in both low and high grade gliomas. These results support that anaerobic glycolysis increased with malignancy in the metabolism of gliomas. The hemodynamics and metabolism of central low density area and peritumoral low density area reflect the pathophysiological state of necrosis and edema respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pituitary enlargement associated with Addison's disease

We report a case of Addison's disease with pituitary enlargement which could easily have been misinterpreted as a pituitary adenoma or other pituitary disease. Serial computed tomography following replacement therapy was essential to confirm the diagnosis.