Vascularization of peripheral neurilemomas: angiographic,computed tomographic,and histologic studies

The vascularization of peripheral neurilemoma was studied in 17 patients, in eight by angiography and in 16 by computed tomography (CT) using contrast enhancement. Angiographically the degree of vascularity varied from scarcity to abundance of vessels. In two patients, arteries connected to the proximal and distal poles of the tumor could be identified as nutrient arteries of the affected nerve, and in three patients some of the veins draining the tumor followed the course of the nerve. All 16 tumors examined by CT showed lower density than skeletal muscle. They were well delineated and at least partially surrounded by adipose tissue. With contrast enhancement the density increased focally, reflecting the distribution of vessels in the tumors. Histologic examination showed that Antoni-A tissue was rich in small (below 15 m) and medium-sized vessels, whereas large vessels (above 100 m) were more frequently seen in Antoni-B tissue. Medium-sized and large vessels often tended to be arranged along the border between Antoni-A and Antoni-B tissues.     

Delayed effects of prenatal low-dose irradiation in the white matter of the rat brain.

PURPOSE: This study is part of a general search for the anatomical bases of the severe mental retardation syndrome caused by prenatal irradiation. More specifically, it seeks reasons for the high radiosensitivity of a white matter area, the cingulum of the corpus callosum. MATERIALS AND METHODS: Pregnant primiparous Wistar rats were exposed to X-rays at 12, 13, 14 or 15 days of gestation (E12, E13, E14 or E15) with single low doses of 180 mGy. A high dose of 500 mGy was given at E15 for a complementary study. The brains of the female offspring were collected at 1 and 3 months of age. The affinity of osmium tetroxide for the white matter was used to recognize and quantify cingulum areas in a series of coronal sections made at different positions along the antero-posterior axis of the brains. RESULTS: A 180 mGy dose of X-rays caused an atrophy of the cingulum; the effect was particularly significant in the 1-month-old brains after an exposure at E13 or at E14, and increased in the 3-month-old animals exposed at E15. The axonal size distribution was unchanged in the 3-month-old cingulums treated with 500 mGy at E15. CONCLUSIONS: The atrophy of the cingulum is due to a loss of axons, which are abundant in this area. As a consequence of axon loss, a reduction of the postnatal myelination enhances the volumetric decrease of the cingulum at 3 months of age.     

Delayed effects of prenatal low-dose irradiation in the white matter of the rat brain

Purpose: This study is part of a general search for the anatomical bases of the severe mental retardation syndrome caused by prenatal irradiation. More specifically, it seeks reasons for the high radiosensitivity of a white matter area, the cingulum of the corpus callosum. Materials and methods: Pregnant primiparous Wistar rats were exposed to X-rays at 12, 13, 14 or 15 days of gestation (E12, E13, E14 or E15) with single low doses of 180mGy. A high dose of 500mGy was given at E15 for a complementary study. The brains of the female offspring were collected at 1 and 3 months of age. The affinity of osmium tetroxide for the white matter was used to recognize and quantify cingulum areas in a series of coronal sections made at different positions along the antero-posterior axis of the brains. Results: A 180mGy dose of X-rays caused an atrophy of the cingulum; the effect was particularly significant in the 1-month old brains after an exposure at E13 or at E14, and increased in the 3-month-old animals exposed at E15. The axonal size distribution was unchanged in the 3-month-old cingulums treated with 500mGy at E15. Conclusions: The atrophy of the cingulum is due to a loss of axons, which are abundant in this area. As a consequence of axon loss, a reduction of the postnatal myelination enhances the volumetric decrease of the cingulum at 3 months of age.     

Metabolite and diffusion changes in the rat brain after Leksell Gamma Knife irradiation.

Our study describes the time course of necrotic damage to the rat brain resulting from Leksell Gamma Knife (LGK) irradiation at a dose that was previously considered to be subnecrotic. A lesion induced in the rat hippocampus by 35 Gy irradiation was monitored by MRI, MRS, and DW-MRI for 16 months. T2-weighted images revealed a large hyperintense area with an increased apparent diffusion coefficient of water (ADCw), which occurred 8 months after irradiation, accompanied by metabolic changes (increase of lactate (Lac) and choline (Cho), and decrease of creatine (Cr) and N-acetyl aspartate (NAA), as determined by MRS) that indicated an edema. In two animals, the hyperintensity persisted and a postnecrotic cavity connected to enlarged lateral ventricles developed. In the rest of the animals, the hyperintensity started to decrease 9 months post-irradiation (PI), revealing hypointense areas with a decreased ADCw. Histology confirmed the MRI data, showing either scar formation or the development of a postnecrotic cavity.     

Renal angiomyolipoma. Ultrasonographic, CT, angiographic, and histologic correlation

The findings at ultrasonography (US), CT, and angiography in 13 patients with renal angiomyolipomas were compared with histologically determined proportions of fatty, myogenic, and vascular components. The angiomyolipoma was composed mainly of fat in 4 cases, half of fat in 2, mainly of myogenic tissue in 4, and was hemorrhagic in 3. US showed high echogenicity in 10 patients, while CT demonstrated attenuation values of fat in 3 tumors with mainly fat tissue but gave non-specific findings in the other cases. The angiographic findings were considered specific for angiomyolipoma in 2 out of 11 cases (18%). Low fat content and hemorrhagic areas caused diagnostic difficulties at both US and CT. The diagnostic algorithm for renal angiomyolipoma is discussed.     

Delayed venous occlusion following embolotherapy of vascular malformations in the brain.

PURPOSE: To describe the nature and features of delayed venous thrombosis following embolization of arteriovenous fistulae. METHODS: Retrospective review of the available clinical history, details of embolization procedures, and results of follow-up angiography were carried out on all embolization procedures performed on high-flow vascular malformations of the brain done at our institution since 1987. RESULTS: Four patients were identified who had delayed (greater than 1 week) venous thrombosis/occlusion after embolization of the malformation associated with neurologic complications. Two patients had arteriovenous fistula and two had vein-of-Galen malformations. These patients had no untoward embolization of the venous outlet as a cause of the venous occlusion. CONCLUSIONS: It is postulated that thrombosis in the arteriovenous fistula group was induced by conversion (due to embolization) of a patulous high flow venous outlet into a slow flow system; in the vein-of-Galen group, the occlusion was thought to be due to high-flow venopathy.     

Endothelial cell population dynamics in rat brain after local irradiation

The dynamics of the endothelial cell population was investigated in the rat brain after local irradiation with different doses of X rays. A fluorescent-histochemical technique was used for the visualization of the cells. A decrease in endothelial cell number was observed within 1 day of irradiation with doses of 5-200 Gy. At this time the endothelial cell number had decreased by up to 15% compared with the pre-treatment values. This early dose-independent loss in cell number was maintained for up to 1 month after irradiation. This was then followed by a slow dose-independent decrease in cell density up to 6 months after exposure. Subsequently the depletion of the endothelial cell population exposed to 40 and 60 Gy continued. After a dose of 25 Gy an abortive recovery of cell numbers occurred followed by an abrupt depletion of the endothelial cell population. The possible mechanisms of such changes are discussed.     

大鼠大脑照射后海马区细胞凋亡与病理形态学变化的研究

目的　了解大鼠大脑受电离辐射后早期海马区细胞凋亡、bcl 2表达和病理形态学变化的情况。方法　用流式细胞仪测定凋亡细胞的比例与bcl 2蛋白的含量 ,用电镜和光镜分别作形态学变化的观察。结果　受 2 0Gy照射后第 1天起海马中就出现了凋亡细胞并逐步增加 ,至照射后3个月时恢复正常 ,而bcl 2蛋白的含量则呈相反的改变。在 3 0Gy照射后 3个月组中有坏死灶的存在 ,而其他组别中可以看到血管、胶质细胞和神经元等组织的形态学异常。结论　大鼠大脑受辐射后早期海马区可发生神经细胞凋亡、bcl 2表达的下降 ,以及各组织成分的病理形态学改变 ,这些变化的程度与照射剂量和观测时间有关。     

Cost-effectiveness of high-dose MR contrast studies in the evaluation of brain metastases.

PURPOSETo investigate the cost-effectiveness of high-dose MR contrast studies in the management of brain metastases.METHODSDuring the phase III clinical trial of high-dose contrast studies (0.3 mmol/kg), 11 of 27 patients were judged by the reviewers to have potential treatment changes based on the additional information provided by the high-dose studies. We retrospectively evaluated how many of these 27 patients had actual treatment changes because of the results of the high-dose study. Using the fee schedule at our institution, the cost-effectiveness was analyzed based on the cost savings from treatment changes and the additional expense of implementing the high-dose studies.RESULTSA total of 3 craniotomies ($22,800 each) and 2 aggressive courses of radiation therapy ($1122 each) were avoided in 4 patients because of the additional lesions detected by the high-dose studies. This resulted in a treatment cost savings of $70,644. The extra expense for implementing the high-dose study is $9126 for a single injection in all 27 patients, $9295 for 2 separate injections completed in 1 visit in the 11 patients, and $11,154 for 2 separate injections completed in 2 separate visits. The cost savings in management (diagnosis and treatment) therefore ranged from $59,490 to $61,518 for all patients and from $2203 to $2278 per patient.CONCLUSIONBased on our limited data, the high-dose study seems to impact positively on the cost-effectiveness in the management of brain metastases. However, because our study had limitations, our results need to be confirmed with a larger patient population and a more standardized treatment approach and fee schedule.     

Pulmonary vascular obstruction in severe ARDS: angiographic alterations after i.v. fibrinolytic therapy

IV streptokinase was infused to test the potential reversibility of adult respiratory distress syndrome (ARDS) associated pulmonary vascular thrombosis in five patients suffering from severe ARDS with elevated mean pulmonary artery pressure, increased pulmonary vascular resistance, and angiographically documented pulmonary vascular thrombosis. At 48 hr there was clearance of obstructions in arteries larger than 1 mm in diameter in all patients, increased filling of the microvasculature and small arteries less than 1 mm in diameter in four patients, a fall in pulmonary vascular resistance in all patients, a rise in cardiac output in four patients, improved oxygenation (PAO2/FlO2) in three patients, and variable changes in shunt fraction and ventilator pressures. Expressed as a mean fraction of the preinfusion controls, the postinfusion physiologic values were pulmonary artery pressure = 0.89 mm Hg, pulmonary vascular resistance = 0.68 mm Hg X min/L, cardiac output = 1.36 L/min, central venous pressure = 0.77 cm H2O, pulmonary capillary wedge pressure = 0.92 mm Hg, PAO2/FlO2 = 1.08, and shunt fraction = 0.95. Follow-up angiography showed no evidence of reocclusion. Postmortem studies of the three nonsurvivors confirmed recanalization of thrombosed pulmonary arteries. One documented bleeding episode occurred. We conclude that fibrinolytic infusion can lyse thrombi and possibly improve hemodynamics and oxygenation in ARDS-associated pulmonary vascular thrombosis.     

Therapy monitoring of presacral recurrences after high-dose irradiation: value of PET, CT, CEA and pain score.

21 patients were followed by positron-emission-tomography (PET) FDG (18Flourdeoxyglucose) uptake, physical examination, CT and CEA levels after combined photon-neutron irradiation for inoperable recurrent rectal carcinoma. In order to evaluate the response to radiotherapy symptomatic relief, CEA levels, decrease of tumor volume measured by CT analysis were correlated with the FDG-uptake. The objective of this study was also to investigate if the level of FDG-uptake prior to radiotherapy or the early decrease after therapy can be used as a prognostic factor. Prior to radiotherapy sacral pain was the predominant symptom. All malignancies showed measurable tumor masses, evaluation of CEA levels and enhanced tracer accumulation of FDG in the PET cross section. The mean FDG-uptake before radiotherapy was 2.3 +/- 1.1 (range 1.1 to 5.0) in 21 patients in contrast to 1.9 +/- 0.7 (range 0.8 bis 4.0) three months after radiotherapy. In six patients FDG concentration values decreased to the range of normal soft tissue, moreover, two of them relapsed after six and 22 months. Elevated FDG-uptake of the sacral bone was noted in PET cross sections in two patients, while there was no evidence of osseous alterations in CT. Normal levels of CEA were achieved in 14 patients and complete or partial pain relief in 20 of 21 patients. A decrease of tumor volume of more than 50% was detected in the follow-up CT scans of three patients but no complete remission was found. The result suggests that enhanced glucose uptake is associated with recurrent rectal cancer. However, enhanced glycolytic activity is related not only to malignant cells but also to all proliferating cells. To distinguish between proliferation, repair, inflammation, and residual viable tumor cells is not possible and may be responsible for an unchanged or elevated FDG-uptake after radiotherapy.     

Fatal late coronary thrombosis after implantation of a radioactive stent: postmortem angiographic and histologic findings--case report.

Postmortem angiography and histologic analysis of a fatal coronary thrombosis 4 months after implantation of a radioactive stent are described. Histologic findings suggested incomplete re-endothelialization in the segment with the stent. Ionizing radiation may delay re-endothelialization after revascularization, thus maintaining the thrombogenicity of the irradiated vessel segment. Thus, prolonged antiplatelet therapy should be considered after intravascular radiation therapy.     

IL-1beta, TNFalpha and IL-6 induction in the rat brain after partial-body irradiation: role of vagal afferents

PURPOSE: To evaluate the central nervous system neuroimmune and inflammatory responses during the prodromal phase of the acute irradiation syndrome in rat brains after partial-body exposure (head-protected) and to investigate the potential neural signalling pathways from the irradiated periphery to the non-irradiated brain. MATERIAL AND METHODS: The study included four groups of rats: one irradiated group and one sham irradiated group, each containing non-vagotomized and vagotomized rats. In vagotomized rat groups, the subdiaphragmatic vagal section surgery was carried out 45 days before the irradiation exposure. The rats were partial-body irradiated with the head shielded with (60)Co gamma-rays to a dose of 15 Gy. They were sacrificed 6 h after the end of exposure. The hypothalamus, hippocampus, thalamus and cortex were then collected, and the concentrations of IL-1beta, TNFalpha and IL-6 in each were measured by ELISA assays. RESULTS: Six hours after irradiation, IL-1beta levels had increased in the hypothalamus, thalamus and hippocampus, and TNFalpha and IL-6 levels had increased significantly in the hypothalamus. Vagotomy before irradiation prevented these responses. CONCLUSIONS: It was concluded that the hypothalamus, hippocampus, thalamus and cortex react rapidly to peripheral irradiation by releasing pro-inflammatory mediators. The results also show that the vagus nerve is one of the major ascending pathways for rapid signalling to the brain with respect to partial body irradiation.     

Histochemical and ultrastructural studies on anti-edematous and radiation-protective action of 0-(beta-hydroxyethyl)-rutosides on the rat brain after single irradiation. 2. Histochemical study on carbohydrate metabolism and acid phosphatase activation

The disturbances of the carbohydrate metabolism and the activation of acid phosphatases with and without protection by O-(beta-hydroxyethyl)-rutoside (HR) were studied in irradiated rat brains by means of the light microscope. The histochemically demonstrable deposition of glycogen and acid mucopolysaccharides serves as a criterion for a reversible lesion of the irradiated cerebral tissue. The extent of local activation of repair processes following to irradiation can be determined by the quantity of acid phosphatases in the lysosomes. For the dose range of 1 to 5 Gy, HR seems to exert a protective effect on the cellular metabolism of the irradiated cerebral tissue shown by a slight decrease of glycogen and mucopolysaccharide deposits compared to the untreated animals. However, when exceeding a threshold dose of 10 Gy, the deposition of carbohydrates in the HR group is strongly increased. A slightly increased activity of acid phosphatases induced by HR can be supposed at best for the dose range of 5 to 7.5 Gy. If the dose is even more increased, the reverse effect found in the carbohydrate metabolism, too, and an increased activation of acid phosphatases in the control group will be observed. This unexpected reversion of the protective effect could be related to the assumed inhibitory effect of HR on the ATPases and thus on the anaerobic part of glycolysis or to a breakdown of the cell interaction system of endothelial cells, glia cells, and neurons.     

Intracranial vascular stenosis and occlusion: MR angiographic findings.

PURPOSETo investigate whether obtaining axial source images from three-dimensional Fourier transform (3DFT) time-of-flight MR angiography improves the detection of intracranial vascular stenosis and occlusion if added to maximum-intensity projection (MIP) images.METHODSThe angiograms of 103 patients who had MR angiography for evaluation of possible intracranial vascular disease were reviewed retrospectively in a quantitative and nonquantitative fashion. Diameters of vessels on MR angiograms were measured quantitatively by two reviewers using a magnifying loupe and compared with the results from conventional angiograms. Degrees of stenoocclusive disease were categorized into five classes; an artery with stenosis of 50% or greater was considered to be diseased. Another five observers also reviewed the MIP images with and without source images in a blinded fashion by means of nonquantitative visual inspection.RESULTSIn all, 23 stenoocclusive lesions of 50% or greater were available for review. In the quantitative analysis, with MIP images alone, 14 (78%) of 18 moderate and severe stenoses and four (80%) of five occlusions were identified correctly. The addition of the source images increased the sensitivity to 100% for moderate and severe stenoses and to 100% for occluded vessels. In the visual inspection study, however, no statistically significant differences were found between interpretations of MIP images alone and those of MIP images in combination with source images.CONCLUSIONIn the quantitative study, interpretation of source images rather than MIP images reduced the tendency to overestimate stenosis seen with MR angiography and improved the sensitivity for detecting stenosis of 50% or greater. There was a discrepancy between the quantitative study and visual inspection. Experienced observers had a tendency to underestimate the degree of stenosis.     

大鼠侧向液压脑损伤后脑血管内血栓形成的实验研究

目的探讨颅脑创伤后脑血管内微血栓形成现象及其与外伤后脑梗死的关系。方法采用鼠侧向液压冲击脑损伤装置建立急性脑创伤模型,受损伤大鼠分别在伤后12、24、72h和7天处死。对照组动物仅行开颅术,无液压冲击。观察脑内微血栓形成部位及数量,并比较各组间脑内血栓数量的差异。结果冲击伤后大鼠脑血管内有大量微血栓形成,与对照组比较差异显著（P〈0．05）。大鼠脑内伤后12h即有血栓形成,此后逐渐增多,伤后7天逐渐下降。此外,在脑内血栓相对集中区域还发现大量的变性神经元。结论颅脑外伤引起脑内广泛血栓形成,可能是外伤后脑梗死的原因之一。