다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

The characterization and calibration of ultrasound imaging systems requires tissue-mimicking phantoms with known acoustic properties, dimensions and internal features. Tissue phantoms are available commercially for a range of medical applications. However, commercial phantoms may not be suitable in ultrasound system design or for evaluation of novel imaging techniques. It is often desirable to have the ability to tailor acoustic properties and phantom configurations for specific applications. A multitude of tissue-mimicking materials and phantoms are described in the literature that have been created using a variety of materials and preparation techniques and that have modeled a range of biological systems. This paper reviews ultrasound tissue-mimicking materials and phantom fabrication techniques that have been developed over the past four decades, and describes the benefits and disadvantages of the processes. Both soft tissue and hard tissue substitutes are explored.

A review of tissue substitutes for ultrasound imaging.

Objective
To examine the significance of power Doppler sonography (PDS) in the diagnosis of synovial hypertrophy of the knee joint by verifying and comparing the PDS findings with histopathologic findings of synovial membrane vascularity.

Methods
The knee joints of 23 patients who were undergoing arthroplasty of the knee joint because of osteoarthritis or rheumatoid arthritis were examined with ultrasound before arthroplasty. The vascularity of the synovial membrane was classified semiquantitatively using PDS. A sample of synovial tissue was obtained during the arthroplasty, and the vascularity of the synovial tissue was evaluated by immunohistochemistry (factor VIII) and was graded qualitatively by a pathologist who was unaware of the PDS findings. The visual qualitative grading by the examiner was controlled by analyzing PDS images and histologic samples using a digital image evaluation system.

Results
The correlation between the qualitative PDS results and the qualitative grading of the vascularity by the pathologist was 0.89 by Spearman's ρ (P < 0.01). The Pearson correlation coefficient between the digital analysis of the PDS images and the digital analysis of the tissue sections was 0.81 (P < 0.01). Digital image analysis and qualitative grading by the examiner had a correlation of 0.89 by Spearman's ρ (P < 0.01) for the PDS images. The correlation between the qualitative estimation of vascularity by the pathologist and the digital image analysis was 0.88 by Spearman's ρ (P < 0.01).

Conclusion
In the present study, PDS proved to be a reliable diagnostic method for qualitative grading of the vascularity of the synovial tissue. In clinical practice, PDS allows further differentiation of the hypertrophic synovium.

Correlation of power Doppler sonography with vascularity of the synovial tissue of the knee joint in patients with osteoarthritis and rheumatoid arthritis

dix A. Even if you don’t choose to memorize them this system aids in reference and retreival of important formulas. The book was compiled from notes developed during eight years of teaching a graduate course on the subject and was used as a text. Thus it has been student tested. Appendix F contains a number of problems, grouped to be used on a chapter by chapter basis The problems are designed to illustrate practical applications of the text material. The parts of this book of most interest and value to the EMC engineer will be the chapters on Thermal Noise, Antennas, Propagation and Transmission Lines, and  Reflection and Refraction. This is not  to downpade the chapters on Statistics and Its Applications, Signal Processing and Detection, and Some System Characteristics which also contain much potentially useful materials. Additional plus values for the book include a list of 40 references, a table of symbols used throughout the book, and a subject index. Some readers may find the condensed type and close line spacing hard to read. It was apparently set up by typewriter using an elite type face with single line spacing. When reduced down to a 6 by 9 5 inch size page it is too crowded for easy reading. In spite of this shortcoming your reviewer recommends this book as a worthwhile reference in this field of interest.

http://ieeexplore.ieee.org/iel5/5/31269/01455368.pdf

Signal analysis

Methodological review: Computerized analysis of pigmented skin lesions: A review

Development of an example flow test object and comparison of five of these test objects, constructed in various laboratories

Conventional measurement of the spectrum of arterial signals from the pulsed ultrasonic Doppler instrument uses windowed, sequential data segments. The Doppler signal is assumed stationary for the duration of each segment. It is shown here that this assumption is often unreasonable and the effect of mean frequency variation during the data segment has been investigated for different windows and rates of change of mean frequency. A data segment length giving maximum spectral resolution is shown to exist for each window type and rate of frequency change.

Nonstationarity broadening in pulsed doppler spectrum measurements

Categorisation for arterial stenoses treatment is determined primarily by the degree of occlusion, which is often estimated ultrasonically from blood velocity measurements. In current single-beam ultrasound (US) systems, this estimate can suffer from gross errors due to angle-dependence. The purpose of this study was to find out if an experimental dual-beam US system could reduce the angle-dependence of the velocity estimates. We compared four dual-beam velocity estimation algorithms on both a string phantom and straight tube wall-less flow phantoms incorporating symmetrical and asymmetrical stenoses from 0% to 91% by area. The estimated maximum velocity varied, on average, by 7.6% for beam-vessel angles from 40 degrees to 80 degrees. The fluctuation in the magnitude estimate was reduced by a factor of 2.6 using a hybrid single-dual-beam algorithm. We conclude that, when the true velocity lies in the scan plane, the dual-beam system reduces the angle-dependence and, thus, has the potential to improve categorisation of patients with arterial stenoses.

Angle-independent estimation of maximum velocity through stenoses using vector Doppler ultrasound

Arterial Doppler signal simulation by time domain processing

BACKGROUND/AIMS: The observation that skin line patterning tends to be disrupted by malignant but not non-malignant skin lesions suggests that this could be used as an aid to lesion differentiation. Since recognised differentiating features can be obtained from the simply-captured white light optical image, the possibility of using such images for skin pattern disruption detection is worth exploring. METHODS: The skin pattern has been extracted from optical images by high-pass filtering and profiles of local line strength variation with the angle estimated using a new consistent high-value profiling technique. The resultant profile images have been analysed using a novel region-based agglomerative clustering technique (mRAC) and also a local variance measurement. A measure based on the relationship between the classification results and an intensity-based segmentation was calculated, and this represented the disruption of the skin line patterning. RESULTS: A set of images containing a variety of histologically confirmed malignant and non-malignant lesions was analysed. The computed textural disruption figure was compared to both the histological diagnosis and to a visual estimate of patterning disruption for each image. It was demonstrated that lesion separation could be achieved by both analysis methods, with a good correlation with visual estimate of disruption and with mRAC providing the best performance. CONCLUSIONS: It was concluded that the acquisition and modelling of skin line patterning from clinical images of skin lesions had been successfully achieved and that the analysis of the resulting data provided an assessment of pattern disruption that is both consistent with visual inspection and effective in presenting information useful for discrimination between melanoma and benign naevi lesion examples.

Peter J. Fish

Papers

Development of an example flow test object and comparison of five of these test objects, constructed in various laboratories

Nonstationarity broadening in pulsed doppler spectrum measurements

Angle-independent estimation of maximum velocity through stenoses using vector Doppler ultrasound

Arterial Doppler signal simulation by time domain processing

Lesion classification using skin patterning.