Novel contrast-enhanced ultrasound imaging in prostate cancer

The purposes of this paper were to present the current status of contrast-enhanced transrectal ultrasound imaging and to discuss the latest achievements and techniques now under preclinical testing. Although grayscale transrectal ultrasound is the standard method for prostate imaging, it lacks accuracy in the detection and localization of prostate cancer. With the introduction of contrast-enhanced ultrasound (CEUS), perfusion imaging of the microvascularization became available. By this, cancer-induced neovascularisation can be visualized with the potential to improve ultrasound imaging for prostate cancer detection and localization significantly. For example, several studies have shown that CEUS-guided biopsies have the same or higher PCa detection rate compared with systematic biopsies with less biopsies needed. This paper describes the current status of CEUS and discusses novel quantification techniques that can improve the accuracy even further. Furthermore, quantification might decrease the user-dependency, opening the door to use in the routine clinical environment. A new generation of targeted microbubbles is now under pre-clinical testing and showed avidly binding to VEGFR-2, a receptor up-regulated in prostate cancer due to angiogenesis. The first publications regarding a targeted microbubble ready for human use will be discussed. Ultrasound-assisted drug delivery gives rise to a whole new set of therapeutic options, also for prostate cancer. A major breakthrough in the future can be expected from the clinical use of targeted microbubbles for drug delivery for prostate cancer diagnosis as well as treatmen

Multiparametric ultrasound in the detection of prostate cancer: a systematic review

PURPOSE: To investigate the advances and clinical results of the different ultrasound modalities and the progress in combining them into multiparametric UltraSound (mpUS). METHODS: A systematic literature search on mpUS and the different ultrasound modalities included: greyscale ultrasound, computerized transrectal ultrasound, Doppler and power Doppler techniques, dynamic contrast-enhanced ultrasound and (shear wave) elastography. RESULTS: Limited research available on combining ultrasound modalities has presented improvement in diagnostic performance. The data of two studies suggest that even adding a lower performing ultrasound modality to a better performing modality using crude methods can already improve the sensitivity by 13-51 %. The different modalities detect different tumours. No study has tried to combine ultrasound modalities employing a system similar to the PIRADS system used for mpMRI or more advanced classifying algorithms. CONCLUSION: Available evidence confirms that combining different ultrasound modalities significantly improves diagnostic performance

Angiogenesis in prostate cancer : onset, progression and imaging

Today, angiogenesis is known to play a key role in cancer growth and development. Emerging cancer treatments are based on the suppression of angiogenesis, and modern imaging techniques investigate changes in the microvasculature that are caused by angiogenesis. As for other forms of cancers, angiogenesis is well recognised as a fundamental process in the development of prostate cancer. The novelty of this extensive report on angiogenesis in cancer, with particular attention on prostate cancer and the imaging techniques able to detect it, is the new prospective to the subject. In contrast with the other available reviews, this report goes from ‘theory’ to ‘practice’, establishing a clear link between angiogenesis development and imaged angiogenesis features. Once the key role of angiogenesis in the development of cancer and in particular prostate cancer has been fully described, attention is turned to the current imaging methods with the potential to assess the angiogenesis process and, as a consequence, to detect and localise prostate cancer. • As confirmed by all available statistics, cancer represents a major clinical and societal problem in the developed world. The form of cancer with the highest incidence in men is prostate cancer. For prostate cancer, as well as for most forms of cancer, detection of the disease at an early stage is critical to reduce mortality and morbidity. • Today, it is well known that pathological angiogenesis represents a crucial step in cancer development and progression. Comparable with most forms of cancer, angiogenesis also plays a fundamental role for prostate cancer growth. • As a consequence, angiogenesis is an ideal target not only for novel anti-angiogenic therapies, but also for modern imaging techniques that aim at cancer localisation by detection of angiogenic microvascular changes. • These techniques are mainly based on magnetic resonance, ultrasound, and nuclear imaging. • This paper provides a comprehensive review of the available studies on angiogenesis in prostate cancer and its use by modern and emerging imaging techniques for prostate cancer localisation

Spatiotemporal correlation of ultrasound contrast agent dilution curves for angiogenesis localization by dispersion imaging

The major role of angiogenesis in cancer development has driven many researchers to investigate the prospects of noninvasive cancer imaging based on assessment of microvascular perfusion. The limited results so far may be caused by the complex and contradictory effects of angiogenesis on perfusion. Alternatively, assessment of ultrasound contrast agent dispersion kinetics, resulting from features such as density and tortuosity, has shown a promising potential to characterize angiogenic effects on the microvascular structure. This method, referred to as contrast-ultrasound dispersion imaging (CUDI), is based on contrast-enhanced ultrasound imaging after an intravenous contrast agent bolus injection. In this paper, we propose a new spatiotemporal correlation analysis to perform CUDI. We provide the rationale for indirect estimation of local dispersion by deriving the analytical relation between dispersion and the correlation coefficient among neighboring time-intensity curves obtained at each pixel. This robust analysis is inherently normalized and does not require curve-fitting. In a preliminary validation of the method for localization of prostate cancer, the results of this analysis show superior cancer localization performance (receiver operating characteristic curve area of 0.89) compared with those of previously reported CUDI implementations and perfusion estimation methods

Spatiotemporal correlation of ultrasound contrast agent dilution curves for angiogenesis localization by dispersion imaging

The major role of angiogenesis in cancer development has driven many researchers to investigate the prospects of noninvasive cancer imaging based on assessment of microvascular perfusion. The limited results so far may be caused by the complex and contradictory effects of angiogenesis on perfusion. Alternatively, assessment of ultrasound contrast agent dispersion kinetics, resulting from features such as density and tortuosity, has shown a promising potential to characterize angiogenic effects on the microvascular structure. This method, referred to as contrast-ultrasound dispersion imaging (CUDI), is based on contrast-enhanced ultrasound imaging after an intravenous contrast agent bolus injection. In this paper, we propose a new spatiotemporal correlation analysis to perform CUDI. We provide the rationale for indirect estimation of local dispersion by deriving the analytical relation between dispersion and the correlation coefficient among neighboring time-intensity curves obtained at each pixel. This robust analysis is inherently normalized and does not require curve-fitting. In a preliminary validation of the method for localization of prostate cancer, the results of this analysis show superior cancer localization performance (receiver operating characteristic curve area of 0.89) compared with those of previously reported CUDI implementations and perfusion estimation methods