Performance of three-dimensional sonoelastography in prostate cancer detection: A comparison between ex vivo and in vivo experiments

Abstract

In this paper, we evaluate and compare the performance of three-dimensional (3D) sonoelastography for prostate cancer detection ex vivo and in vivo. Ultrasound (US) Bmode and sonoelastographic volumes were acquired from eleven prostate glands before and after radical prostatectomy. Semiautomatic algorithms were used to segment the surface of the gland from the US B-mode volume and the tumors from sonoelastographic data. To assess the detection performance, 3D sonoelastographic findings were compared in size and position to 3D histological data. One gland was discarded due to poor contact. In the remaining ten, both, in vivo and ex vivo sonoelastography showed similar performance in prostate cancer detection: over 80% accuracy for tumors larger than 4 mm in estimated diameter. These results are an improvement over US B-mode but not yet sufficient to replace biopsy. However, 3D sonoelastography has the potential to become an imaging tool to guide biopsies.

Prostate Elastography

“…5. Vibration amplitude sonoelastography [15][16][17]. Although there are a multitude of elastographic techniques, they are all based on the same concept of applying a force and imaging the resulting ti ssue response.…”

“…These vibrations are monitored using a specially designed ultrasound Doppler processing mode. Regions of decreased amplitude are associated with stiffer structures in the tissue [15][16][17]27].…”

“…The stiff structure (dark) in the apical region on patient left shown in the ARFI images at the red asterisk corresponds to the large cancerous region d iameters: 7.4 mm visualized, 3.8 mm missed), and 12 false positive regions were identified, 6 of which corresponded to BPH. The primary challenges associated with this method are the inability to detect small tumors and difficulty in coupling enough vibration energy into the tissue [15,16].…”

Viscoelastic characterization of elliptical mechanical heterogeneities using a semi-analytical shear-wave scattering model for elastometry measures

“…Static elastography takes advantage of the Hooke's law in the linear domain to establish relative strain maps, called elastograms. In-vivo studies using static elastography demonstrated the relevance of the technique for breast (Wojcinski et al, 2010;Schaefer et al, 2011) and prostate cancer screening (Castaneda et al, 2009), despite operator dependency limitations. Shear wave elastography imaging (SWEI) (Sugimoto et al, 1990;Rudenko et al, 1996;Sarvazyan et al, 1998) is another technique allowing quantitative estimation of the shear modulus, by assessing velocity of propagating shear waves.…”

Clinical applications of sonoelastography

“…Their results indicated that sonoelastography had the capability to detect lesions over 1cc [3]. More recently, Castaneda et al evaluated 30 ex vivo [4] and 11 in vivo [5] prostate glands. In both cases, sonoelastograhpic findings were compared to histological results by employing image segmentation and registration tools.…”