Intraocular pressure-dependent dynamic changes of optic disc cupping in adult glaucoma patients.

The authors performed a study of intraocular pressure-dependent changes in optic disc cupping in 17 adults with chronic open-angle glaucoma. Analyses with the Rodenstock Optic Nerve Head Analyzer were performed at baseline low intraocular pressure during therapy, after elevation of intraocular pressure (from therapeutic failure or noncompliance), and after reduction of intraocular pressure with successful therapy. Optic disc cupping increased significantly upon short-term increase of intraocular pressure from baseline of 20.4 +/- 2.5 mmHg to 31.1 +/- 5.9 mmHg. Optic disc cupping reverted to baseline after persistent intraocular pressure reduction to 19.3 +/- 4.8 mmHg. These data demonstrate intraocular pressure-dependent dynamic changes of optic disc cupping in patients with demonstrable glaucomatous optic nerve damage. They underscore the detrimental effect of elevated intraocular pressure and the beneficial effect of intraocular pressure reduction on optic disc cup changes.     

Immunohistochemical study of lymph nodes in patients with cat scratch disease.

BACKGROUND/PURPOSE: Bartonella henselaeis the causative agent of cat scratch disease (CSD), manifesting as fever and acute regional lymphadenopathy. Although serologic testing is the reference method for diagnosis, successful use of immunohistochemical (IHC) stain of regional lymph nodes for the diagnosis of CSD has been reported. To determine the characterization and diagnostic potential of IHC in lymphadenopathy of CSD, lymph nodes were excised from patients with suspected CSD for further evaluation. METHODS: Polyclonal antibody-based IHC studies were performed for the detection of B. henselae. Between January 2001 and December 2004, the reference laboratory of the Center for Disease Control, Taiwan, received a total of 377 sera from 352 reported suspected CSD cases. Twenty-three formalin-fixed paraffin-embedded lymph nodes from 16 patients and two skin biopsies from two patients suspected of having CSD were included in this study. Nine of them were serologically confirmed to have CSD and the others were seronegative but suspected to have CSD by the attending physicians. Seven lymph node specimens were obtained from tuberculosis patients for comparison. RESULTS: We demonstrated that the microorganisms existed in the cytoplasm of histiocytes within the granulomatous lesions in nine lymph nodes and one skin biopsy. Among the nine lymph nodes with IHC (+) stains, three were seronegative. On the other hand, three cases were IHC (+) and six cases were IHC (-) among nine seronegative patients. In addition, two seronegative patients with skin biopsy showed one IHC (+) and one IHC (-). CONCLUSION: IHC can contribute to the etiologic diagnosis of B. henselaelymphadenopathy when serology and molecular techniques are not available.     

Dynamic evaluation of 18F-FDG uptake by microPET and whole-body autoradiography in a fibrosarcoma-bearing mouse model.

BACKGROUND AND PURPOSE: Fluorine-18-2-deoxy-D-glucose (18F-FDG) has been used in the clinic as a diagnostic radiotracer for monitoring many kinds of tumors, but its value for monitoring fibrosarcoma is not well established. METHODS: In this study, the uptake of 18F-FDG in a fibrosarcoma-bearing mouse model was evaluated using the high resolution positron emission tomography (PET) system microPET. Tumor cells were implanted in 3 FVB/N mice, and static microPET scanning was performed on day 1, 7, 12 and 15 after implantation. A dynamic microPET image was scanned on day 12 to determine the 18F-FDG uptake in 3 other tumor-bearing mice. Time-activity curves were plotted by drawing regions of interest in the tumor, liver, kidneys and muscles. The mice were sacrificed after dynamic microPET imaging and whole-body autoradiography (WBAR) was performed. For biodistribution study, 9 tumor-bearing mice, 3 per experimental group, were studied at 3 time points and the results were compared with the static microPET images. RESULTS: MicroPET images suggested that 18F-FDG could be used to monitor the growth of tumors 7 days after implantation. Dynamic scans of 18F-FDG uptake reached a plateau in the tumor after 20 minutes on day 12 after implantation. Both microPET and WBAR revealed evidence of tumor necrosis. The results of biodistribution and WBAR agreed with those from microPET images. CONCLUSION: MicroPET was useful for monitoring the growth of fibrosarcoma and determination of the maximal uptake time point of 18F-FDG in tumors in this tumor-bearing mouse model.     

A Study of Grid Artifacts Formation and Elimination in Computed Radiographic Images

Computed radiography (CR) has many advantages such as filmless operations, efficiency, and convenience. Furthermore, it is easier to integrate with the picture archiving and communication systems. Another important advantage is that CR images generally have a wider dynamic range than conventional screen film. Unfortunately, grid artifacts and moiré pattern artifacts may be present in CR images. These artifacts become a more serious problem when viewing CR images on a computer monitor when a clinic grade monitor is not available. Images produced using a grid with higher frequency or a Potter–Bucky grid (i.e., a moving grid, Bucky for short) can reduce occurrence but cannot guarantee elimination of these artifacts [CR & PACS (2000); Detrick F (2001), pp 7–8]. In this paper, the formation of the artifacts is studied. We show that the grid artifacts occur in a narrow band of frequency in the frequency domain. The frequency can be determined, accurately located, and thus removed from the frequency domain. When comparing the results obtained from the proposed method against the results obtained using previous computer methods, we show that our method can achieve better image quality.     

高原环境对部队适应人群内分泌系统的急性效应

本文对初入海拔5170米高原5日内未发生急性高山病的46名新战士进行了17项内分泌指标的检测,发现高原环境对适应人群内分泌系统的急性效应主要有:下丘脑一垂体应激反应增强;甲状腺功能增强;皮质醇分泌增多,醛固酮分泌减少,肾素活性降低,血管紧张素Ⅱ增多;性腺功能无明显变化。     

Sensitivity-encoded (SENSE) proton echo-planar spectroscopic imaging (PEPSI) in the human brain.

Magnetic resonance spectroscopic imaging (MRSI) provides spatially resolved metabolite information that is invaluable for both neuroscience studies and clinical applications. However, lengthy data acquisition times, which are a result of time-consuming phase encoding, represent a major challenge for MRSI. Fast MRSI pulse sequences that use echo-planar readout gradients, such as proton echo-planar spectroscopic imaging (PEPSI), are capable of fast spectral-spatial encoding and thus enable acceleration of image acquisition times. Combining PEPSI with recent advances in parallel MRI utilizing RF coil arrays can further accelerate MRSI data acquisition. Here we investigate the feasibility of ultrafast spectroscopic imaging at high field (3T and 4T) by combining PEPSI with sensitivity-encoded (SENSE) MRI using eight-channel head coil arrays. We show that the acquisition of single-average SENSE-PEPSI data at a short TE (15 ms) can be accelerated to 32 s or less, depending on the field strength, to obtain metabolic images of choline (Cho), creatine (Cre), N-acetyl-aspartate (NAA), and J-coupled metabolites (e.g., glutamate (Glu) and inositol (Ino)) with acceptable spectral quality and localization. The experimentally measured reductions in signal-to-noise ratio (SNR) and Cramer-Rao lower bounds (CRLBs) of metabolite resonances were well explained by both the g-factor and reduced measurement times. Thus, this technology is a promising means of reducing the scan times of 3D acquisitions and time-resolved 2D measurements.