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21.
生理影像是功能性医学影像的一个重要分支,也是临床医学工程的一个极其重要的研究和应用领域。多年来,作者及其研究生与临床医务人员相结合,在电生理影像和热生理影像的信息获取和数字化处理技术方面进行了大量及深入的研究,提出了一种体内热估计(ITE)新技术。本文重点介绍热生理影像信息在妇女乳腺癌诊断中的应用。通过对约五千例妇女乳腺病筛选的结果,表明了生理影像信息处理及ITE技术在临床医学上的应用价值。 相似文献
22.
不同类型正常乳腺表观扩散系数值差异的研究 总被引:4,自引:0,他引:4
目的 研究不同类型正常乳腺表观扩散系数(ADC)值的差异,探讨ADC值与组织学分型之间的关系。方法 采用单次激发平面回波(EPI)技术,扩散敏感因子(b)值分别为0、500、1000s/mm^2,对62个正常乳腺(包括42例乳腺病变患者的对侧正常乳腺及10名健康志愿者20个乳腺)进行MR扫描及MR扩散加权成像(DWI)检查,计算62个正常乳腺分别在不同b值时的ADC值。将62个正常乳腺分为3型,比较3型之间ADC值的差异及不同b值时ADC值的差异。结果 42例乳腺病变患者对侧正常乳腺的DWI及ADC图与组织切片对比,不同类型乳腺组织学结构不同,其DWI及ADC图表现亦有差异。62个正常乳腺分为致密型10个,分叶斑点型42个及退化型10个。致密型和分叶斑点型乳腺随b值降低ADC值升高,而退化型乳腺随b值降低ADC值变化不明显。b=1000—0s/mm^2时,致密型、分叶斑点型、退化型乳腺ADC值分别为(1.70±0.37)、(1.93±0.46)、(1.18±0.65)×10^-3mm^2/s,3组间比较差异有统计学意义(F=12.998,P=0.000)。不同b值时每2种类型间进行单因素方差分析,致密型和分叶斑点型之间差异无统计学意义(F=2.167,P=0.147);致密型和退化型之间、分叶斑点型和退化型之间差异均有统计学意义(F值分别为5.593、19.128,P值分别为0.029、0.000)。结论 3型正常乳腺ADC值受乳腺组织学结构的影响,致密型和分叶斑点型乳腺ADC值受b值高低的影响。 相似文献
23.
Scott Lozanoff Barbara A. Long David L. Singer John J. Deptuch 《Journal of clinical periodontology》1992,19(8):553-559
Deposits of dental plaque or calculus are typically quantified using planimetric techniques. However, error is introduced into a quantitative analysis of plaque deposits using these methods, since they require a significant amount of human intervention. The purpose of this study is to describe and validate a computerized imaging routine which has the potential to objectively identify material on dental roots and measure the area covered by these deposits. Dentiform teeth with simulated plaque were videorecorded. A computer routine was developed based on a flood-fill algorithm which analyzed images of the dentiform teeth and determined the amount of simulated plaque on their root surfaces. Results showed that the dentiform teeth and their simulated plaque patterns are duplicated by the imaging routine in a rapid and reliable fashion. The system shows a high degree of accuracy with an average error factor of only 0.58%. As well, the system enables precise reproducibility with an average error factor of only 0.71%. 相似文献
24.
An image processing system for application to studies of the temporal and spatial parameters of movement during swallowing
and speech is described. Image sequences from videotape are digitized for computerized manipulation and analysis in an attempt
to improve on conventional visual inspection. The system is “interactive” or “event-driven”: after executing a function, the
computer waits for guidance from the user who controls the program through keyboard and mouse input, selecting options from
menus and responding to prompts. The analyst alters image clarity by the application of filters and heightens contrast through
video enhancement. A technique called “remapping” reduces head motion and provides uniform spatial scaling. Animated sequences
of images are used, as opposed to frame-by-frame analysis, to preserve temporal context and increase efficiency of measurement.
Low cost off-the-shelf personal computer hardware is used along with original software tailored to the application. 相似文献
25.
随着科学技术的不断进步,为了尽快适应新形势的发展,招飞体检中我们在脑电图(dectroencephalogram,EEG)检测方面使用了电子计算机技术,并对新仪器应用于脑功能检测工作的价值进行了相关的研究,现报告如下: 相似文献
26.
刘尊年 《菏泽医学专科学校学报》2002,14(4):84-85
目的 探讨血细胞自动计数的方法。方法 采用微机彩色图像处理技术对血液细胞图像进行图像分割和细胞计数。结果 与人工计数相平行 ,相关系数r =0 .96 1~ 0 .997,P >0 .0 5。结论 该方法可行且计数相对精确、迅速、客观 相似文献
27.
A general model is developed for segmenting magnetic resonance images using vector decomposition and probabilfty techniques. Each voxel is assigned fractional volumes of q tissues from p differently weighted images (q ≤ p + 1) in the presence of partial-volume mixing, random noise, and other tissues. Compared wtth the eigenimage method, fewer differently weighted images are needed for segmenting the q tissues, and the contrast-to-noise ratio in the calculated fractional volumes is improved. The model can produce com-posrte tissue-type images similar to that of the probability methods, by comparing the fractional volumes assigned to different tissues on each voxel. A three-tissue (p = 2, q = 3) model is illustrated for segmenting three tissues from dual-echo images. M provides statistical analysis to the algebraic method. A three-compartment phantom is segmented for validation. Two clinical examples are presented. 相似文献
28.
JOSEPH ROCHFORD ANANDA P SEN ISABELLE ROUSSE SHARON A WELNER 《Brain research bulletin》1996,41(5):313-317
Latent inhibition (LI) is a reduction in the rate of acquisition of a Pavlovian conditioned response that results from prior nonreinforced preexposure to a conditioned stimulus (CS). LI has been suggested to reflect the operation of mechanisms involved in stimulus selection for subsequent cognitive processing. The present experiment was conducted to assess the effect of bilateral lesions of the nucleus basalis magnocellularis (NBM) on LI employing a conditioned emotional response paradigm. Bilateral lesions of the NBM were produced by administration of 0.12 M quisqualic acid and resulted in decreased cortical acetylcholinesterase staining, as well as a 40% reduction in cortical choline acetyltransferase activity. Following lever press training, preexposed animals received 40 presentations of a 60-s tone CS. Nonpreexposed animals received no tone presentations. Acquisition of conditioned suppression was then assessed over the course of 4 tone-shock (0.6 mA, 0.5 s) pairings. Control, preexposed animals displayed a retarded rate of acquisition in comparison to nonpreexposed controls, thereby demonstrating that the parameters used in the present experiment produced LI. In contrast, lesioned animals preexposed to the CS acquired conditioned suppression as readily as non-preexposed lesioned animals. However, the acquisition of conditioned suppression in both lesioned groups was found to be similar to that displayed in the preexposed control group. This pattern of results was interpreted as being attributable to a lesion-induced impairment in the ability to maintain stimulus processing, rather than a deficit in the ability to filter a stimulus. Copyright © 1996 Elsevier Science Inc. 相似文献
29.
Advances in processing of surface myoelectric signals: Part 1 总被引:10,自引:0,他引:10
R. Merletti Dip. di Elettronica L. R. Lo Conte 《Medical & biological engineering & computing》1995,33(3):362-372
During sustained voluntary or electrically elicted muscle contractions the surface myoelectric signal is nonstationary and
it undergoes progressive changes reflecting the modifications of the motor unit action potentials and their propagation velocity.
In particular, during sustained electrical stimulation, the evoked signals show progressive amplitude, time scaling and shape
modification. The quantitative evaluation of these changes is important for non-invasive muscle characterisation and may be
performed in either the time or frequency domain using parametric and nonparametric spectral analysis as well as alternative
methodologies. The paper introduces the detection techniques, reviews and compares the methods of spectral estimation based
on FFT and autoregressive models, and discusses their applications and limitations in extracting information from the surface
myoelectric signal with particular regard to myoelectric manifestations of localised muscle fatigue during sustained contractions. 相似文献
30.
Harwant S. Gill Michael W. O'Boyle Julie Hathaway 《Cortex; a journal devoted to the study of the nervous system and behavior》1998,34(5):707-718
Alpha power (8–12 Hz) was monitored over the frontal, temporal, parietal and occipital lobes of the left and right cerebral hemispheres while participants mentally rotated three-dimensional shapes to match a specified target. By comparing the activational patterns generated during three experimental conditions, each designed to systematically isolate the involvement of the various subcomponents comprising this mental rotation task, it was suggested that the right frontal lobe mediates encoding and comparison/decision processes, while the left parietal and the left temporal region appear most involved in the generation of images and their mental rotation. A preliminary model describing the cooperative interaction of these cortical regions during mental rotation tasks is proposed. 相似文献