Driven by progress in sensor technology, computer methods and data processing capabilities, 3D laser scanning has found a wide range of new application fields in recent years. Particularly, monitoring the static and dynamic behaviour of large dams has always been a topic of great importance, due to the impact these structures have on the whole landscape where they are built. The main goal of this paper is to show the relevance and novelty of the laserscanning methodology developed, which incorporates different statistical and modelling approaches not considered until now. As a result, the methods proposed in this paper have provided the measurement and monitoring of the large “Las Cogotas” dam (Avila, Spain).

Ankylosing spondylitis (AS) is not fully explained by inflammatory processes. Clinical, epidemiological, genetic, and course of disease features indicate additional host-related risk processes and predispositions. Collectively, the pattern of predisposition to onset in adolescent and young adult ages, male preponderance, and widely varied severity of AS is unique among rheumatic diseases. However, this pattern could reflect biomechanical and structural differences between the sexes, naturally occurring musculoskeletal changes over life cycles, and a population polymorphism. During juvenile development, the body is more flexible and weaker than during adolescent maturation and young adulthood, when strengthening and stiffening considerably increase. During middle and later ages, the musculoskeletal system again weakens. The novel concept of an innate axial myofascial hypertonicity reflects basic mechanobiological principles in human function, tissue reactivity, and pathology. However, these processes have been little studied and require critical testing. The proposed physical mechanisms likely interact with recognized immunobiological pathways. The structural biomechanical processes and tissue reactions might possibly precede initiation of other AS-related pathways. Research in the combined structural mechanobiology and immunobiology processes promises to improve understanding of the initiation and perpetuation of AS than prevailing concepts. The combined processes might better explain characteristic enthesopathic and inflammatory processes in AS.

A method for improving the contrast resolution of B-mode images is proposed by combining the speckle-reduction technique of frequency compounding (FC) and the coded excitation and pulse-compression technique called resolution enhancement compression (REC). FC suppresses speckle but at the expense of a reduction in axial resolution. Using REC, the axial resolution and bandwidth of the imaging system was doubled. Therefore, by combining REC with FC (REC-FC), the tradeoff between axial resolution and contrast enhancement was extended significantly. Simulations and experimental measurements were conducted with a single-element transducer (f/2.66) having a center frequency of 2.25 MHz and a -3-dB bandwidth of 50%. Simulations and measurements of hyperechoic (+6 dB) tissue-mimicking targets were imaged. Four FC cases were evaluated: full-, half-, third-, and fourth-width of the true impulse response bandwidth. The image quality metrics used to compare REC-FC to conventional pulsing (CP) and CP-FC were contrast-to-noise ratio (CNR), speckle signal-to-noise ratio, histogram pixel intensity, and lesion signal-to-noise ratio. Increases in CNR of 121%, 231%, 302%, and 391% were obtained in experiments when comparing REC-FC for the full-, half-, third-, and fourth-width cases to CP. Furthermore, smaller increases in CNR of 112%, 233%, and 309% were obtained in experiments when comparing CP-FC for the half-, third-, and fourth-width cases to CP. Improved lesion detectability was observed by using REC-FC.

Conventional B-mode imaging in ultrasound consists of displaying the log-compressed envelope of the backscattered signal. While clinical ultrasonic B-mode images have good spatial resolution, i.e., better than a millimeter, the contrast resolution of ultrasonic B-mode images is typically low. However, additional information is contained in the ultrasonic backscattered signal, which can be used to create images related to tissue microstructure. Because diagnosis of disease is typically based on histological examination of tissue microstructure, the ability to quantify and describe tissue microstructure through ultrasound may result in improved diagnostic capabilities of ultrasound. Tissue-mimicking phantoms and animal models of breast cancer were used to assess the ability of novel ultrasonic imaging techniques to quantify microstructure. Four parameters were extracted from the ultrasonic backscattered signal and related to the microstructure. The effective scatterer diameter (ESD) and the effective acoustic concentration (EAC) parameters were based on modeling the frequency dependence of the backscatter. The k parameter (which quantifies the periodicity of scatterer locations) and the mu parameter (which estimates the number of scatterers per resolution cell) were based on modeling the statistics of the backscattered envelope. Images constructed with these parameters resulted in an increase in contrast between diseased tissue and normal tissues but at the expense of spatial resolution. Specifically, in simulation, quantitative ultrasound (QUS) increased the contrast-to-noise ratio (CNR) between targets and background by more than 10 times in some cases. Statistically significant differences were observed between three kinds of tumors using the ESD, EAC, and k parameters. QUS imaging was also improved with the addition of coded excitation. A novel coded excitation technique was used that improved the variance of estimates over conventional pulsing methods, e.g- , the variance of ESD estimates were reduced by a factor of up to 10.

Quantitative ultrasound (QUS) imaging techniques make use of information from backscattered echoes discarded in conventional B-mode imaging. Using scattering models and spectral fit methods, properties of tissue microstructure can be estimated. The variance of QUS estimates is usually reduced by processing data obtained from a region of interest (ROI) whose dimensions are larger than the resolution cell of B-mode imaging, which limits the spatial resolution of the technique. In this work, the use of full angular (i.e., 360 •) spatial compounding is proposed to extend the trade-off between estimate variance and spatial resolution of QUS. Simulations were performed using an f/4, 10-MHz transducer with 50%-6-dB bandwidth and a synthetic phantom consisting of two eccentric circular cylindrical regions. The inner and outer cylinders had radii of 7 mm and 12.5 mm, respectively, and nine scatterers per resolution cell. The average scatterer diameters (ASDs) for the outer and inner cylinders were 50 μm and 25 μm, respectively. ASD estimates were obtained using radio frequency data at up to 128 angles of view. When using ROIs of size 16λ by 16λ, the use of multiple view data reduced the ASD standard deviations in the outer and inner cylinders from 7.4 μm and 14.4 μm to 1.5 μm and 2.5 μm, respectively. When using ROIs of size 8λ by 8λ, the use of multiple view data reduced the ASD standard deviations in the outer and inner cylinders from 13.7 μm and 19.6 μm to 2.5 μm and 3.7 μm, respectively. Experimental validation was obtained using a 10 MHz, f/4 transducer to analyze a 2 cm diameter homogeneous agar phantom with embedded glass spheres of diameters between 45 μm and 53 μm. When using ROIs of size 10λ by 10λ and 32 angles of view, the ASD standard deviation was reduced from 24.6 μm to 4.8 μm. This value was below 10.4 μm, the ASD standard deviation obtained using single view data and ROIs of size 20λ by 20λ. Therefore, the use of full angular compounding was found to significantly improve the trade-off between spatial resolution in QUS imaging and precision of QUS estimates. These results suggest that QUS imaging can achieve optimal performance on a platform capable of producing views of an object from 360 • , e.g., a tomographic breast scanner.