Computed tomography of anorexia nervosa

Computed tomographic studies were performed in patients with anorexia nervosa to confirm the observations of other authors on so-called reversible cerebral atrophy. In 21 of 23 cases a marked enlargement of the cortical sulci and the interhemispheric fissures was observed, which was reversed in a second computed tomographic study in 11 patients 4 weeks after they had reached normal weight. Psychological tests were carried out at the same time as the computed tomographic studies to correlate the changes in the brain tissue with cerebral function. Data obtained in each group of tests for both the initial and the follow-up studies were analyzed using the Student t-test. The differences were found to be statistically significant (p = 0.01 in most cases). The results indicate that anorexia nervosa is not only a psychodynamic problem, but also one in which an organic brain lesion plays an important role during the course of the illness.     

Reversible and non-reversible enlargement of cerebrospinal fluid spaces in anorexia nervosa

Summary Brain CT studies of 35 patients with anorexia nervosa confirmed the observations of other authors: cerebral dystrophic changes correlate with weight loss and the reversibility of these changes also correlates with the normalization of body weight. Other corroborated facts are: the most numerous and most pronounced enlargements are of the cortical sulci and the interhemispheric fissure, moderate widening affects the ventricles and the rarest and most insignificant changes are those of the cerebellum. The reversibility of the changes showed a parallel to the extent of the changes themselves and to the duration of improvement of the body weight. The reversibility of the enlargement of the cortical sulci and of the distances between the frontal horns of the lateral ventricles was more often significant than that of the abnormal measurements of the cella media. This difference is based on minimal early acquired brain damage which occurs in 60% of our patients. This high incidence of early acquired minimal brain disease in patients with anorexia nervosa is here discussed as a nonspecific predisposing factor. Although there is no exact explanation of the etiology of the reversible enlargement of cerebrospinal fluid (CSF) spaces in anorexia nervosa, the changes resemble those in alcoholics. The mechanisms of brain changes in alcoholism, as shown experimentally, seem to us to throw light on the probable mechanism of reversible dystrophic brain changes in anorexia nervosa.     

Sodium time course using 23Na MRI in reversible focal brain ischemia in the monkey

Purpose

To demonstrate the use of sodium MRI for measuring the time course of tissue sodium concentration (TSC) in a nonhuman primate model of reversible focal brain ischemia.

Materials and Methods

Reversible endovascular focal brain ischemia was induced in nonhuman primates (n = 4), and sodium MRI was performed on a 3 Tesla scanner for monitoring changes in TSC during both the middle cerebral artery (MCA) occlusion and MCA reperfusion portions of the experiment.

Results

The TSC increased linearly in the ischemic tissue during MCA occlusion (ranging from a mean TSC increase of 5.44%/h to 7.15%/h across the four subjects), and then there was a statistically significant change from a positive TSC slope during MCA occlusion to a TSC slope after MCA reperfusion that was not statistically different from zero. The linear increase in sodium MRI during brain ischemia was used to estimate the stroke onset time to within 0.45 h in each of the four subjects (with a maximum 95% confidence interval of ± 1.147 h).

Conclusion

The data indicate that sodium MRI increases linearly during brain ischemia, and that this increase is stopped by tissue reperfusion within 5.4 h after stroke onset. J. Magn. Reson. Imaging 2009;30:219–223. © 2009 Wiley‐Liss, Inc.     

Change in brain size during and after pregnancy: study in healthy women and women with preeclampsia

BACKGROUND AND PURPOSE: Qualitative decreases in maternal brain size have been observed late in pregnancy. The aim of this study was to quantitatively evaluate changes to the maternal brain during and after healthy pregnancy and to compare these changes with those observed in cases of preeclampsia. METHODS: Three-dimensional T1-weighted MR volume images were obtained in nine healthy participants before and after delivery. Additional images were obtained in some of these participants before pregnancy, during pregnancy, and within 52 weeks after delivery. Five women with preeclampsia were examined before delivery and 6 weeks after delivery. Three of these patients were examined within 52 weeks after delivery. Images were registered, and both brain and ventricular volumes were calculated by using a semiautomated computer program. RESULTS: Both the healthy and preeclamptic groups had a reduction in brain size during pregnancy that was maximal at term and that reversed by 6 months after delivery. The ventricular size showed a corresponding increase in size during pregnancy and a decrease in size after delivery. In the preeclamptic patients, brain size was significantly smaller (P =.05) than in healthy participants, both before and after delivery. CONCLUSION: The brain decreases in size during pregnancy and increases in size after delivery. The changes follow a consistent time course in each woman. The mechanism and physiologic importance of these findings are speculative at the present time.     

Reversibility of ecstasy-induced reduction in serotonin transporter availability in polydrug ecstasy users

Purpose Animal data suggest that the synthetic drug ecstasy may damage brain serotonin neurons. Previously we reported protracted reductions in the availability of the serotonin transporter (SERT), an index of integrity of the axon terminals of brain serotonergic neurons, in SERT-rich brain regions in current human ecstasy users. Comparison of current ecstasy users and former ecstasy users yielded some evidence that this reduction might be reversible. However, participant selection effects could not be ruled out. Therefore, follow-up examinations were performed in these subjects to test the following a priori hypothesis in a prospective longitudinal design that eliminates participant selection effects to a large extent: availability of the SERT increases towards normal levels when ecstasy use is stopped, and remains unchanged or is further decreased if use is continued.Methods Two follow-up positron emission tomography measurements using the SERT ligand [¹¹C](+)McN5652 were completed by 15 current and nine former ecstasy users. All subjects used illicit drugs other than ecstasy, too. The time interval between repeated measurements was about 1 year. The time course of the availability of the SERT was analysed in the following SERT-rich regions: mesencephalon, putamen, caudate and thalamus.Results Current ecstasy users showed a consistent increase in the availability of the SERT in the mesencephalon during the study (Friedman test: p=0.010), which most likely was caused by a decrease in the intensity of ecstasy consumption (Spearman correlation coefficient –0.725, p=0.002). Former ecstasy users showed a consistent increase in SERT availability in the thalamus (Friedman test: p=0.006).Conclusion Ecstasy-induced protracted alterations in the availability of the SERT might be reversible.     

Nearly completely reversible brain abnormalities in a patient with incontinentia pigmenti

SUMMARY: We report a case of incontinentia pigmenti with reversible cortex and subcortical white matter necrosis-like presentation by MR imaging. The reversible changes in follow-up imaging of the patient with incontinentia pigmenti suggest a course of natural repair of inflammation or cerebrovascular disease.     

On the timing characteristics of the apparent diffusion coefficient contrast in fMRI.

For the past 10 years, functional MRI (fMRI) has seen rapid progress in both clinical and basic science research. Most of the imaging techniques are based on the blood oxygenation level-dependent (BOLD) contrast which arises from the field perturbation of the paramagnetic deoxyhemoglobin due to the mismatch between the local oxygen demand and delivery. Because the changes of oxygenation level take place mostly in the veins, the dominant signal sources of the BOLD signal are intra- and extravascular proton pools of the veins. Perfusion imaging methods, developed parallel to the BOLD technique, seek to quantify the blood flow and perfusion. Recently, perfusion imaging using arterial spin tagging methods have been used to study brain function by investigating the changes of the blood flow and perfusion during brain activation, thereby generating an alternative contrast mechanism to the functional brain imaging. Since most of these methods require tagging pulse and wait time for blood to be delivered to the imaged slice, the temporal resolution may not be optimal. Dynamic intravoxel incoherent motion (IVIM) weighting schemes using apparent diffusion coefficient (ADC) contrast were suggested to image the relative changes of the in-plane blood flow during brain function. In this report, it was demonstrated that, in addition to the spatial discrepancies of the activated areas, the time course based on the ADC contrast consistently precedes that from the BOLD contrast with timing offset on the order of 1 sec. Since arterial networks would have different spatial locations and preceding temporal characters, the findings in this report are indicative that the ADC contrast is sensitive to the arterial blood flow changes.     

Ultrastructural changes in the rat cerebellar cortex in the remote periods after exposure to accelerated carbon ions

The cerebellar cortex of rats irradiated with carbon ion fluxes of 320 Mev/nuclon and 60Co gamma-radiation was examined by light and electron microscopy 1, 3 or 6 months after exposure. Carbon ions induced the greatest pathomorphological changes. A month after exposure the changes were diffuse and reversible while 3 and, especially, 6 months after irradiation they were focal disorders, a large portion of which being irreversible. 3 and 6 months after exposure some structures of the cerebellar cortex showed destructive while others exhibited reparative changes. Structural disorders in various nerve and glial cells were of different type. Disorders of the Purkinje cells were of the dark type and those of adjacent Bergmann glial cells of the light type. In the granular layer, neurons showed light type changes and adjacent oligodendrocytes, a densely packed karyo- and cytoplasm and a higher osmiophilia. It can be assumed that the above changes are to maintain disordered neuronal functions, including cell interactions. Study of time course variations in the neuronal and glial ultrastructure of the cerebellar cortex of irradiated animals shows an increase of destructive changes with time. This investigation has demonstrated that CNS cells may be damaged long after exposure even to small fluxes of heavy charged particles.     

尾部悬吊及恢复过程中大鼠动脉血管收缩反应的变化

目的 探讨模拟失重下动脉收缩反应变化的时程特征及其可逆性。方法 采用尾部悬吊大鼠模型模拟失重,利用离休动脉环测定血管收缩反应的变化。结果 尾部悬吊２ｗｋ后,大鼠的腹主动脉、肠系膜动脉和股动脉收缩反应明显降低,而颈总动脉无明显改变;悬吊４ｗｋ后,肠系膜动脉和股动脉的收缩反应与悬吊２ｗｋ相比有进一步的降低;悬吊８ｗｋ大鼠的动脉血管收缩反应性与悬吊４ｗｋ相比无明显差异;４ｗｋ尾部悬吊大鼠解除悬吊后５ｗｋ     

Dynamic changes in water ADC,energy metabolism,extracellular space volume,and tortuosity in neonatal rat brain during global ischemia

To obtain a better understanding of the mechanisms underlying early changes in the brain water apparent diffusion coefficient (ADC) observed in cerebral ischemia, dynamic changes in the ADC of water and in the energy status were measured at postnatal day 8 or 9 in neonatal rat brains after cardiac arrest using ¹H MRS/MRI and ³¹P MRS, respectively. The time courses of the MR parameters were compared with changes in the extracellular space (ECS) volume fraction (α) and tortuosity (λ), determined from concentration-time profiles of tetramethylammonium applied by iontophoresis. The data show a decrease of the ADC of tissue water after induction of global ischemia of which the time course strongly correlates with the time course of the decrease in the ECS volume fraction and the increase in ECS tortuosity. This indicates that cell swelling is an important cause for the ADC decrease of water.     

Posterior reversible encephalopathy syndrome (PRES) with immune system activation, VEGF up-regulation, and cerebral amyloid angiopathy

The case of a 75-year-old man with a history of lymphoma, recent upper respiratory tract infection, and a protracted course of encephalopathy is presented. Radiologically, findings were consistent with posterior reversible encephalopathy syndrome. A brain biopsy revealed evidence of endothelial activation, T-cell trafficking, and vascular endothelial growth factor expression, suggesting that systemic immune system activation may be involved with triggering posterior reversible encephalopathy syndrome. In addition, underlying cerebral amyloid angiopathy may have contributed to the initial nonclassical edema distribution by compromising autoregulatory blood flow mechanisms.     

Hemodynamic and permeability changes in posterior reversible encephalopathy syndrome measured by dynamic susceptibility perfusion-weighted MR imaging

BACKGROUND AND PURPOSE: The physiological mechanism that gives rise to posterior reversible encephalopathy syndrome (PRES) is currently unknown. We sought to better understand the mechanism of the edema formation in PRES and specifically hypothesized that this edema is caused by increased vascular permeability. METHODS: Eight consecutive patients with PRES who had been studied by using perfusion MR imaging were retrospectively identified. Perfusion images were obtained using a gradient-echo echo planar sequence with contrast enhancement. Measures of apparent diffusion coefficient (ADC), cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT) and vascular permeability (K2) were calculated in the affected posterior brain areas and normalized to values obtained in unaffected anterior brain. These values were compared with those found in healthy subjects. RESULTS: Regions of interest within the posterior affected brain indicated a significant increase in ADC values in all but one patient, a significant decrease in CBV and CBF values in all patients with PRES (average 30% of control), variable changes in MTT, and no measurable change in K2. CONCLUSION: The decrease in both CBV and CBF in PRES supports the theory of autoregulatory vasoconstriction; changes in K2 were not detected.     

尾部悬吊大鼠不同部位动脉血管的分化性结构重塑变化及其可逆性

目的 阐明模拟失重下,不同部位动脉血管的结构是否会发生不同性质的重塑变化,这些变化是否可逆。方法 用ｖａｎ Ｇｉｅｓｏｎ－Ｏｒｃｅｉｎ染色法观察了尾部悬吊４ｗｋ（ＳＵＳ－４）,县吊４ｗｋ后恢复１ｗｋ（ＲＥＣ－１）,及对照（ＣＯＮ）大鼠后肢和头颈部动脉血管的形态学改变。结果 股动脉及胫前动脉：与ＣＯＮ比较,ＳＵＳ－４组的内径与中膜布告匀显著减小;ＲＥＣ－１组的ｄ与Ａ尚未完全恢复,但差别已不显著。     

Detecting activations in event-related fMRI using analysis of variance.

The most common design of a functional MRI (fMRI) experiment is a block design. The use of rapid imaging, however, and carefully designed paradigms makes the separation of cognitive events possible. Such experiments make use of event-related paradigms, in which a task involving several cognitive processes is repeated. In analyzing data from such experiments, existing methods often prove inadequate, because the prediction of the exact shape or timing of the time course is difficult. Here we present an analysis of variance (ANOVA) method for analyzing fMRI data that does not require any assumptions about the shape of the activation time course. Consequently, this method can simultaneously detect brain areas showing a variety of stimulus-locked time courses in the same experiment. The utility of this technique is demonstrated by the analysis of data from two event-related paradigms in which regions of activation are detected that correspond to a variety of distinct neural processes, yielding significantly different temporal signal changes. Magn Reson Med 42:1117-1122, 1999.     

Measuring the change in CBV upon cortical activation with high temporal resolution using look-locker EPI and Gd-DTPA.

A method of simultaneously measuring the changes in cerebral blood volume (CBV) and T(*) (2) that occur on brain activation with high temporal resolution was developed. The method involves measuring the change in the longitudinal relaxation time (T(1)) that occurs following a bolus injection of Gd-DTPA and converting this measurement to a change in blood volume assuming fast exchange. The sequence was optimized for the measurement of changes in CBV with high temporal resolution. A change in CBV of 27 +/- 4% on activation of the primary visual cortex (V1) was measured across four subjects. The time course of changes in T(*) (2) showed a poststimulus undershoot (P = 0.008) corresponding approximately to a period over which CBV was still elevated above baseline, but falling (P = 0.01). The effects of perfusion, nonfulfillment of the assumption of fast exchange and of intrinsic T(1) changes on activation on the model used to calculate the change in CBV are discussed.     

Alcohol-induced changes in the brain as assessed by MRI and CT

This review provides an overview of structural magnetic resonance imaging and computed tomography findings of direct and indirect alcohol-related toxic effects on the brain. In addition to ethanol-related changes to the brain, this article will also describe imaging findings in the acute setting of methanol and ethylene glycol poisoning. Alcohol will lead to brain atrophy, osmotic myelinolysis, Marchiafava–Bignami disease and, especially when related to malnutrition, may also cause Wernicke encephalopathy. Brain atrophy can be reversible if alcohol abuse is stopped. If not treated, Wernicke encephalopathy can lead to coma and death and an early diagnosis is important for immediate initiation of thiamine substitution. As clinical symptoms are often unspecific, the radiologist plays an important role in the detection of alcohol abuse and its related clinical conditions.     

高频喷射呼吸对猫脑功能衰竭的复苏作用

利用双侧颈总动脉并双侧推动脉夹闭致猫缺血性脑功能衰竭模型,观察了高频喷射呼吸(HFJV)对猫单纯脑功能衰竭的复苏作用。结果证明,HFJV可以明显提高猫耐受脑映血的能力,增加可逆性脑功能衰竭猫的生存机率及延长永久性脑功能衰竭猫的生存时间,有利于脑复苏。     

CT and MRI in severe hypophosphataemia with central nervous system involvement

We report a 38-year-old woman with extreme hypophosphataemia in whom CT and MRI disclosed bilateral lesions within the basal ganglia, thalamus and occipital lobes. After adequate substitution of phosphate the lesions grossly resolved and the patient recovered. This case is the first to demonstrate that profound changes of serum phosphate may be associated with reversible brain lesions. Received: 27 March 1999/Accepted: 16 June 1999     

脑损害昏迷患者脑状态实时监测的研究及应用

目的评价脑状态指数（cerebral state index，CSI）、肌电指数（electromyographic，EMG）、爆发抑制指数（burst suppression，BS）等指标在量化昏迷深度及监测脑功能损害程度中的作用。方法对50例临床脑损害昏迷患者进行脑状态监测（cerebral state monitor，CSM），分析这些指标与患者的体征反射、听觉诱发电位（AEP）、格拉斯哥昏迷评分（GCS）及格拉斯哥预后评分（GOS）改变的关系。结果CSI 0～100是从清醒到深昏迷、脑死亡一个连续不断的刻度范围，与患者昏迷深度确切相关，与GCS、体征反射相应消涨；在恒定刺激作用下的CSI变化，结合BS、EMG能够准确判断患者预后，量化脑功能的改变并赋予其相应的临床意义。结论通过CSM获得量化的、数字化的脑功能损害程度，可以实时判定昏迷深度及昏迷动态演变过程，客观地指导临床救治和把握预后，根本改善了根据临床表现来评定所存在的明显的人为差异、缺少客观物证的昏迷及预后评分的现状。     

肝豆状核变性的影像学表现及成像相关因素探讨

目的 研究肝豆状核变性（HLD）的CT、MR和B超表现,探讨影响影像表现的相关因素。方法 54例HLD患者中,男35例,女9例,年龄3－40岁。作CT检查29例,MR检查11例,其中两者同时检查者5例。B超检查26例。结果 （1）脑部MRI呈长T1、长T2信号9例,稍短T1、短T2信号2例。病灶位于壳核11例,尾状核8例,丘脑5例,苍白球2例,红核2例,黑质3例,大脑脚网状结构1例,脑桥桥核2例,额叶白质1例。典型者依受累部位不同,分别表现为“啄木鸟”、“八字”、“展翅蝴蝶”样改变等。（2）脑部CT检查25例中,阳性18例（72％）,阴性7例（28％）。主要表现为双侧基底节区对称性低密度影。（3）肝脏B超26例均示慢性肝病声像学改变,伴肝硬化12例,脾肿大11例,腹水9例,胆囊水肿8例,双边影5例,胆囊结石3例。结论 （1）MRI T2信号和CT密度改变与临床表现往往不相平行。T1信号可用于随访比较,但不易定量。（2）HLD几乎都有肝损害,肝损害先天脑损害;早期肝损害呈可逆性,脑损害呈对称性;中期肝损害呈静止性;后期脑损害呈萎缩性。（3）提出影响CT、MR图像表现的4对矛盾因素：代谢性全身性疾病与基因选择性亲和性;铜沉积与细胞损伤;内源性自主排铜与组织细胞修复;外源性驱铜治疗与组织细胞修复。