18F-FDG PET/CT for detecting nodal metastases in patients with oral cancer staged N0 by clinical examination and CT/MRI.

(18)F-FDG PET has a high accuracy in staging head and neck cancer, but its role in patients with clinically and radiographically negative necks (N0) is less clear. In particular, the value of combined PET/CT has not been determined in this group of patients. METHODS: In a prospective study, 31 patients with oral cancer and no evidence of lymph node metastases by clinical examination or CT/MRI underwent (18)F-FDG PET/CT before elective neck dissection. PET/CT findings were recorded by neck side (left or right) and lymph node level. PET/CT findings were compared with histopathology of dissected nodes, which was the standard of reference. RESULTS: Elective neck dissections (26 unilateral, 5 bilateral; a total of 36 neck sides), involving 142 nodal levels, were performed. Only 13 of 765 dissected lymph nodes harbored metastases. Histopathology revealed nodal metastases in 9 of 36 neck sides and 9 of 142 nodal levels. PET was TP in 6 nodal levels (6 neck sides), false-negative in 3 levels (3 neck sides), true-negative in 127 levels (23 neck sides), and false-positive in 6 levels (4 neck sides). The 3 false-negative findings occurred in metastases smaller than 3 mm or because of inability to distinguish between primary tumor and adjacent metastasis. TP and false-positive nodes exhibited similar standardized uptakes (4.8 +/- 1.1 vs. 4.2 +/- 1.0; P = not significant). Sensitivity and specificity were 67% and 85% on the basis of neck sides and 67% and 95% on the basis of number of nodal levels, respectively. If a decision regarding the need for neck dissection had been based solely on PET/CT, 3 false-negative necks would have been undertreated, and 4 false-positive necks would have been overtreated. CONCLUSION: (18)F-FDG PET/CT can identify lymph node metastases in a segment of patients with oral cancer and N0 neck. A negative test can exclude metastatic deposits with high specificity. Despite reasonably high overall accuracy, however, the clinical application of PET/CT in the N0 neck may be limited by the combination of limited sensitivity for small metastatic deposits and a relatively high number of false-positive findings. The surgical management of the N0 neck should therefore not be based on PET/CT findings alone.     

Four-dimensional (4D) PET/CT imaging of the thorax

We have reported in our previous studies on the methodology, and feasibility of 4D-PET (Gated PET) acquisition, to reduce respiratory motion artifact in PET imaging of the thorax. In this study, we expand our investigation to address the problem of respiration motion in PET/CT imaging. The respiratory motion of four lung cancer patients were monitored by tracking external markers placed on the thorax. A 4D-CT acquisition was performed using a "step-and-shoot" technique, in which computed tomography (CT) projection data were acquired over a complete respiratory cycle at each couch position. The period of each CT acquisition segment was time stamped with an "x-ray ON" signal, which was recorded by the tracking system. 4D-CT data were then sorted into 10 groups, according to their corresponding phase of the breathing cycle. 4D-PET data were acquired in the gated mode, where each breathing cycle was divided into ten 0.5 s bins. For both CT and PET acquisitions, patients received audio prompting to regularize breathing. The 4D-CT and 4D-PET data were then correlated according to respiratory phase. The effect of 4D acquisition on improving the co-registration of PET and CT images, reducing motion smearing, and consequently increase the quantitation of the SUV, were investigated. Also, quantitation of the tumor motions in PET, and CT, were studied and compared. 4D-PET with matching phase 4D-CTAC showed an improved accuracy in PET-CT image co-registration of up to 41%, compared to measurements from 4D-PET with clinical-CTAC. Gating PET data in correlation with respiratory motion reduced motion-induced smearing, thereby decreasing the observed tumor volume, by as much as 43%. 4D-PET lesions volumes showed a maximum deviation of 19% between clinical CT and phase- matched 4D-CT attenuation corrected PET images. In CT, 4D acquisition resulted in increasing the tumor volume in two patients by up to 79%, and decreasing it in the other two by up to 35%. Consequently, these corrections have yielded an increase in the measured SUV by up to 16% over the clinical measured SUV, and 36% over SUV's measured in 4D-PET with clinical-CT Attenuation Correction (CTAC) SUV's. Quantitation of the maximum tumor motion amplitude, using 4D-PET and 4D-CT, showed up to 30% discrepancy between the two modalities. We have shown that 4D PET/CT is clinically a feasible method, to correct for respiratory motion artifacts in PET/CT imaging of the thorax. 4D PET/CT acquisition can reduce smearing, improve the accuracy in PET-CT co-registration, and increase the measured SUV. This should result in an improved tumor assessment for patients with lung malignancies.     

脑性瘫痪患儿合并癫疒间32例临床分析

目的探讨合并癫疒间的脑性瘫痪患儿的临床特点及癫疒间治疗效果。 方法总结1999年10月至2004年5月在西安交通大学第二医院住院的合并癫疒间的脑性瘫痪患儿的癫疒间发生率、临床类型、头颅计算机体层成像(CT)和(或)磁共振成像(MRI)、脑电图等方面的特点以及抗癫疒间治疗效果。 结果139例脑性瘫痪患儿中有32例合并癫疒间，占230%(32/139)；常见的癫疒间类型为强直 阵挛发作12例(375%)和部分性发作6例(188%)；25例(781%)癫疒间首发于1岁前；合并癫疒间脑性瘫痪儿童的头颅影像异常及脑电图异常分别占30例(938%)和27例(844%)；常见的头颅影像异常为脑发育不良11例(367%)、脑积水6例(200%)，余为脑萎缩、缺氧缺血性脑病样改变等13例(433%)；脑电图异常中局灶性和弥漫性所占比例分别为482%(13/27)和518%(14/27)；癫疒间多发生于痉挛性脑性瘫痪中(688%)；813%(26/32)的癫疒间需要2种及2种以上的抗癫疒间药物治疗。 结论脑性瘫痪患儿中癫疒间的发生率较高，其头颅影像学和脑电图分别以脑发育不良和弥漫性背景活动异常伴疒间样波发放为主；脑性瘫痪儿童的癫疒间大多为难治性，需要联合用药治疗。     

Depolarizing/hyperpolarizing effects of the GABA(A) synapse have a beneficial role in synaptic weight resetting in the hippocampus

To eliminate undesirable memory traces from the short-term memory system, it is a crucial question to reorganize the activity induced synaptic efficiency. Here we suggest a possible solution for this mechanism. In the first part of the paper we demonstrate, that under different physiological conditions even in the case of adult animals, the GABA(A) synapse may mediate a depolarizing effect on the membrane potential. Considering the GABA(A) receptor-mediated complex effects on the membrane potential of adult mammalian central neurons we raised the question of the properties of the network, which has elements in the synaptic weight matrix with changing signs. The second part pinpoints the beneficial learning ability of such a network.     

螺旋CT对大面积脑梗死的诊断与鉴别诊断

目的探讨大面积脑梗死的螺旋CT诊断与鉴别诊断。方法回顾性分析45例大面积脑梗死患者完整资料,其中27例大面积脑梗死是脑血管栓塞引起,12例是其它部位栓子脱落引起,6例是由于外伤性血管损伤引起。45列患者均在临床症状出现后2 h²4 d内行头颅CT平扫,经积极治疗后均行头颅CT复查。结果 45例患者均在脑实质内出现大片状低密度影,累及脑灰白质。结论螺旋CT能准确诊断大面积脑梗死,特别是外伤后出现的大面积脑梗死时,为该病的治疗提供有价值的数据和资料支持,避免医疗引纷的发生。     

Evaluation of an automated deformable image matching method for quantifying lung motion in respiration-correlated CT images

We have evaluated an automated registration procedure for predicting tumor and lung deformation based on CT images of the thorax obtained at different respiration phases. The method uses a viscous fluid model of tissue deformation to map voxels from one CT dataset to another. To validate the deformable matching algorithm we used a respiration-correlated CT protocol to acquire images at different phases of the respiratory cycle for six patients with nonsmall cell lung carcinoma. The position and shape of the deformable gross tumor volumes (GTV) at the end-inhale (EI) phase predicted by the algorithm was compared to those drawn by four observers. To minimize interobserver differences, all observers used the contours drawn by a single observer at end-exhale (EE) phase as a guideline to outline GTV contours at EI. The differences between model-predicted and observer-drawn GTV surfaces at EI, as well as differences between structures delineated by observers at EI (interobserver variations) were evaluated using a contour comparison algorithm written for this purpose, which determined the distance between the two surfaces along different directions. The mean and 90% confidence interval for model-predicted versus observer-drawn GTV surface differences over all patients and all directions were 2.6 and 5.1 mm, respectively, whereas the mean and 90% confidence interval for interobserver differences were 2.1 and 3.7 mm. We have also evaluated the algorithm's ability to predict normal tissue deformations by examining the three-dimensional (3-D) vector displacement of 41 landmarks placed by each observer at bronchial and vascular branch points in the lung between the EE and EI image sets (mean and 90% confidence interval displacements of 11.7 and 25.1 mm, respectively). The mean and 90% confidence interval discrepancy between model-predicted and observer-determined landmark displacements over all patients were 2.9 and 7.3 mm, whereas interobserver discrepancies were 2.8 and 6.0 mm. Paired t tests indicate no significant statistical differences between model predicted and observer drawn structures. We conclude that the accuracy of the algorithm to map lung anatomy in CT images at different respiratory phases is comparable to the variability in manual delineation. This method has therefore the potential for predicting and quantifying respiration-induced tumor motion in the lung.     

Circulating adhesion molecules in sera of asthmatic children before and after steroid therapy.

The aim of this study was to evaluate respiratory function tests, total eosinophil counts, serum immune globulin E (IgE), and serum concentrations of soluble intercellular adhesion molecule (sICAM)1, soluble vascular cell adhesion molecule (sVCAM) 1, and soluble P-selectin (sP-selectin) levels in the children with mild and/or moderate asthma before and 3 months after inhaled steroids and to determine whether adhesion molecule levels showed any difference between asthmatic and healthy children and whether these levels changed with disease activity. A total of 28 children with bronchial asthma and 24 children as a control group were included in the study. All of the patients in the study group were administered inhaled budesonide treatment. The patients were reevaluated 3 months later. Respiratory functions tests were performed and total eosinophil count and serum total IgE level were determined. Serum levels of sICAM-1, sVCAM-1, and sP-selectin were determined and skin-prick tests were performed. Significant difference paralleled to clinical improvement was found in the study group for respiratory function tests, total eosinophil count, serum IgE level, and sICAM-1 levels determined before and after the treatment. However, no significant difference was found for sP-selectin and sVCAM-1 levels before and after the treatment. The higher level of sICAM-1 before the treatment suggests that leukocyte-endothelial adhesion have a role in bronchial asthma, which is an inflammatory airway disease. Reduction in the level of sICAM-1 after the treatment may be related to the decreased inflammation in response to therapy. However, no strong relationships were found between the determinants representing the inflammation and respiratory function tests.     

Protective effect of β-glucan on lung injury after cecal ligation and puncture in rats

Objective Understanding the biological mediators involved in the complex inflammatory response of sepsis and acute lung injury offers the possibility of future investigations targeting treatment based on these mediators. This study investigated whether macrophage activator -glucan has a protective effect on acute lung injury in an experimental model of sepsis.Design and setting Experimental study in an experimental research center.Materials 30 rats randomized into three groups (sham, sepsis, and -glucan).Interventions Cecal ligation and puncture were performed in the -glucan and sepsis groups. The -glucan group was given a single intraperitoneal dose of -glucan (4 mg/kg) following cecal ligation.Measurements and results Rats treated with -glucan had fewer circulating neutrophils, more blood monocytes, and higher serum interleukin 6 levels than septic animals. The percentages of neutrophils and lymphocytes from the bronchoalveolar lavage fluid and the myeloperoxidase activity measured in the lung tissue were lower in the -glucan group than in the sepsis group. Less alveolar hemorrhage and neutrophil infiltration were observed in lungs from animals in the -glucan group in the septic groups.Conclusions In this rat model of intra-abdominal sepsis -glucan treatment partially protected against secondary lung injury, decreased lung hemorrhages, and lung neutrophilia. These results suggest that -glucan protects against sepsis-associated lung damage.