Novel ultrasound features for the identification of the vulnerable carotid plaque

Background: The identification of the vulnerable carotid plaque is of paramount importance in order to prevent the significant stroke-related mortality and morbidity. Currently the clinical decision-making around this condition is based on the traditional ultrasound evaluation of the degree of stenosis. However, there is emerging evidence supporting that this is not sufficient for all patients. Aim of this thesis: The evaluation of novel carotid plaque features for the characterisation of plaque composition, volume and motion using 2 and 3 dimensional ultrasound technology. The ultimate goal is to identify novel sensitive imaging markers for carotid plaque characterisation and stroke-risk stratification. Methods: The Asymptomatic Carotid Stenosis and Risk of Stroke (ACSRS) Study was a large prospective multicentre trial that was recently completed. A post-hoc analysis of the sonographic and clinical data from this study was performed in order to evaluate the effectiveness of novel ultrasound texture features, such as second order statics, on stroke-risk prediction. In addition, the change of specific texture features and degree of stenosis during the ACSRS follow-up time (8 years) and their importance for stroke prediction was evaluated. In order to assess the potential of 3D ultrasound carotid imaging we also developed a special methodology using a 3D broadband, linear array probe and the Q-lab software. This methodology was then applied in a clinical, cross-sectional study of patients with symptomatic and asymptomatic carotid disease. Finally we developed a carotid plaque motion analysis methodology that we tested on a feasibility study. Results: The post-hoc analysis of more than 1, 000 patients from the ACSRS database showed that there are novel ultrasound features of plaque homogeneity that can contribute to plaque characterisation and improve stroke-risk prediction. Similarly our results suggest that the change of degree of stenosis or plaque’s composition through time might have significant predictive value when combined with the above novel features. The study in 3D ultrasound prospectively assessed more than 80 people with symptomatic and asymptomatic carotid disease with both 2 and 3D carotid ultrasound without, though, revealing any significant benefit from the use of 3D imaging in terms of stroke-risk prediction. Finally, our feasibility study on plaque motion analysis showed that it is possible to objectively characterise plaque motion, using ultrasound and dedicated software without complicated reconstructions. Conclusion: The use of novel 2D ultrasound texture features in combination with traditional ones can improve the stroke-risk stratification. 3D ultrasound is a promising new approach, however, the current technology does not appear to offer a significant benefit in comparison to cheaper traditional 2D ultrasound for carotid plaque evaluation. Further research is warranted on this issue.Open Acces

Tendinopatía rotuliana: Análisis termográfico y cuantificación de la señal Doppler intratendón.

La tendinopatía rotuliana es una patología frecuente entre los deportistas y cursa con alteraciones estructurales y fisiológicas que se pueden valorar mediante técnicas de imagen como la ecografía o la termografía infrarroja. El papel de la inflamación en las tendinopatías ha suscitado un notable debate durante décadas, aunque en la actualidad se está empezando a considerar un modelo en el que el proceso degenerativo convive junto al inflamatorio en el desarrollo de esta patología. El estudio de la temperatura, la señal Doppler intratendón y la ecotextura pueden resultar de interés al aportar información sobre el estado del tejido y el nuevo modelo fisiopatológico de tendinopatía, lo que permitiría adoptar un mejor abordaje y seguimiento de los tratamientos sobre la tendinopatía rotuliana. Objetivo: Analizar de forma fiable la señal Doppler intratendón, la resistencia vascular, la temperatura y los parámetros ecotexturales de primer orden (ecointensidad y ecovariación) en la tendinopatía rotuliana. Metodología: Esta tesis se presenta en formato de estudios individuales a modo de artículos que representan los principales apartados de la investigación. Cada uno de los estudios presenta una metodología propia, pero con una línea común: analizar la respuesta térmica, la hipervascularización intratendón y la ecotextura de la tendinopatía rotuliana a través de diferentes técnicas de imagen. Resultados: los resultados de la tesis son los resultados de cada uno de los artículos que la componen: 1) el nuevo método de análisis termográfico del tendón rotuliano mediante la superposición de regiones de interés (ROI), presenta una muy buena fiabilidad y reproducibilidad sobre las variables de tamaño, posición y temperatura media de la región de interés. 2) El nuevo método semiautomático de análisis de imagen para evaluar la señal Doppler y la resistencia vascular intratendón en la tendinopatía rotuliana, ha obtenido una muy buena fiabilidad y reproducibilidad sobre las variables de número, morfológicas y de resistencia vascular de las señales Doppler intratendón y, además, 3) este método es una buena variable predictora del índice de resistencia, ofreciendo una correlación excelente entre ambas variables. 4) En los deportistas con tendinopatía rotuliana unilateral se ha observado un aumento de la temperatura, una VR más baja y una mayor área de DS intratendón con respecto a deportistas control y a los tendones asintomáticos contralaterales. La ecovariación fue la única variable ecotextural analizada que presentó diferencias con el tendón asintomático contralateral, mostrándose moderadamente más alto. Conclusiones: La termografía y la cuantificación de la señal Doppler intratendón son técnicas fiables y potencialmente válidas para el análisis del estado del tendón en la tendinopatía rotuliana, y han permitido observar una mayor temperatura y una baja resistencia vascular intratendón como posibles signos inflamatorios en relación al modelo fisiopatológico de convivencia del proceso inflamatorio y degenerativo de la tendinopatía rotuliana.Terapia y Rehabilitació

Advancements and Breakthroughs in Ultrasound Imaging

Ultrasonic imaging is a powerful diagnostic tool available to medical practitioners, engineers and researchers today. Due to the relative safety, and the non-invasive nature, ultrasonic imaging has become one of the most rapidly advancing technologies. These rapid advances are directly related to the parallel advancements in electronics, computing, and transducer technology together with sophisticated signal processing techniques. This book focuses on state of the art developments in ultrasonic imaging applications and underlying technologies presented by leading practitioners and researchers from many parts of the world

Characterization of alar ligament on 3.0T MRI: a cross-sectional study in IIUM Medical Centre, Kuantan

INTRODUCTION: The main purpose of the study is to compare the normal anatomy of alar ligament on MRI between male and female. The specific objectives are to assess the prevalence of alar ligament visualized on MRI, to describe its characteristics in term of its course, shape and signal homogeneity and to find differences in alar ligament signal intensity between male and female. This study also aims to determine the association between the heights of respondents with alar ligament signal intensity and dimensions. MATERIALS & METHODS: 50 healthy volunteers were studied on 3.0T MR scanner Siemens Magnetom Spectra using 2-mm proton density, T2 and fat-suppression sequences. Alar ligament is depicted in 3 planes and the visualization and variability of the ligament courses, shapes and signal intensity characteristics were determined. The alar ligament dimensions were also measured. RESULTS: Alar ligament was best depicted in coronal plane, followed by sagittal and axial planes. The orientations were laterally ascending in most of the subjects (60%), predominantly oval in shaped (54%) and 67% showed inhomogenous signal. No significant difference of alar ligament signal intensity between male and female respondents. No significant association was found between the heights of the respondents with alar ligament signal intensity and dimensions. CONCLUSION: Employing a 3.0T MR scanner, the alar ligament is best portrayed on coronal plane, followed by sagittal and axial planes. However, tremendous variability of alar ligament as depicted in our data shows that caution needs to be exercised when evaluating alar ligament, especially during circumstances of injury

Case series of breast fillers and how things may go wrong: radiology point of view

INTRODUCTION: Breast augmentation is a procedure opted by women to overcome sagging breast due to breastfeeding or aging as well as small breast size. Recent years have shown the emergence of a variety of injectable materials on market as breast fillers. These injectable breast fillers have swiftly gained popularity among women, considering the minimal invasiveness of the procedure, nullifying the need for terrifying surgery. Little do they know that the procedure may pose detrimental complications, while visualization of breast parenchyma infiltrated by these fillers is also deemed substandard; posing diagnostic challenges. We present a case series of three patients with prior history of hyaluronic acid and collagen breast injections. REPORT: The first patient is a 37-year-old lady who presented to casualty with worsening shortness of breath, non-productive cough, central chest pain; associated with fever and chills for 2-weeks duration. The second patient is a 34-year-old lady who complained of cough, fever and haemoptysis; associated with shortness of breath for 1-week duration. CT in these cases revealed non thrombotic wedge-shaped peripheral air-space densities. The third patient is a 37‐year‐old female with right breast pain, swelling and redness for 2- weeks duration. Previous collagen breast injection performed 1 year ago had impeded sonographic visualization of the breast parenchyma. MRI breasts showed multiple non- enhancing round and oval shaped lesions exhibiting fat intensity. CONCLUSION: Radiologists should be familiar with the potential risks and hazards as well as limitations of imaging posed by breast fillers such that MRI is required as problem-solving tool

Application of infrared thermography in computer aided diagnosis

The invention of thermography, in the 1950s, posed a formidable problem to the research community: What is the relationship between disease and heat radiation captured with Infrared (IR) cameras? The research community responded with a continuous effort to find this crucial relationship. This effort was aided by advances in processing techniques, improved sensitivity and spatial resolution of thermal sensors. However, despite this progress fundamental issues with this imaging modality still remain. The main problem is that the link between disease and heat radiation is complex and in many cases even non-linear. Furthermore, the change in heat radiation as well as the change in radiation pattern, which indicate disease, is minute. On a technical level, this poses high requirements on image capturing and processing. On a more abstract level, these problems lead to inter-observer variability and on an even more abstract level they lead to a lack of trust in this imaging modality. In this review, we adopt the position that these problems can only be solved through a strict application of scientific principles and objective performance assessment. Computing machinery is inherently objective; this helps us to apply scientific principles in a transparent way and to assess the performance results. As a consequence, we aim to promote thermography based Computer-Aided Diagnosis (CAD) systems. Another benefit of CAD systems comes from the fact that the diagnostic accuracy is linked to the capability of the computing machinery and, in general, computers become ever more potent. We predict that a pervasive application of computers and networking technology in medicine will help us to overcome the shortcomings of any single imaging modality and this will pave the way for integrated health care systems which maximize the quality of patient care