Tissue elasticity imaging for diagnosis of prostate cancer: A preliminary report

Abstract

Background: Elastography is a diagnostic imaging technique that evaluates the hardness of a lesion. It is expected to become a new diagnostic modality for prostate cancer. The aim of this study was to examine the usefulness of elastography in the diagnosis of prostate cancer. Methods: A total of 29 patients with untreated, histologically proven prostate cancer were examined using an elastographic imaging technique. The patient was scanned in the dorsosacral position and the prostate was manually compressed with a transrectal ultrasonic probe. The echo signals from inside the tissue were measured before and after the tissue compression and an elastogram was generated by spatially differentiation of the displacement distribution. Results: Elastography depicted the cancer lesion as a harder tissue than the surrounding normal prostatic tissue. Elastography successfully detected 93% (27 patients) of the untreated prostate cancer lesions. Detection of cancer lesions using elastography was significantly higher than by digital rectal examination (59%; 17 patients) and transrectal ultrasonography (55%; 16 patients). Conclusion: Elastography has great potential as a useful modality for diagnosis of prostate cancer. Differentiation between cancerous and normal tissues can be expected to become more accurate as a result of technical advances in the quantification of tissue hardness.

An Intelligent Interface for Freehand Strain Imaging

“…One approach that to some extent handles this problem is a display in which each strain image is overlaid on the B-scan as a "colour wash", where colour indicates strain and brightness is partly determined by the ultrasound signal amplitude [7,18]. In so far as ultrasound signal amplitude correlates with the accuracy of strain estimates, this goes some way to indicating the quality of the strain data.…”

“…Regarding the colour scheme, our options include the use of a wide range of saturated colours, producing the effect of a contour display (as for example in the blue-cyan-green-yellow-red scale of [7] and [18]), but for the present demonstration we favour a dichromatic scale, which is qualitatively closer to traditional intensity-based displays, and which may avoid distorting the features that are perceived to appear in each image. Aiming for maximum colour variation across our example scale, we use green and magenta at the extremes, varying from strong green (high strain/soft) through grey (medium strain/medium stiffness) to magenta (low strain/stiff).…”

“…Quasistatic strain imaging was first tested clinically for breast scanning [4] and breast screening has ever since been a key driver for research [7,23,24]. Numerous studies have been motivated by prostate screening [18,21]. Detection and staging of deep vein thrombosis also seems particularly promising [3], and there are many other possible applications.…”

Reply

“…Details of the method used are not described extensively, although they refer to their recent study 7 conducted on pregnant women in the third trimester of pregnancy based on real-time elastography. In this paper 7 , Fuchs and colleagues simply stated that: 'the Hitachi 7500 ultrasound device uses the method designed by Shiin et al allowing for real-time assessment of the tissue elasticity', giving no reference; after searching online we found some studies carried out by Tsuyoshi Shiina, to which we suppose Fuchs et al were referring, that used real-time freehand elasticity imaging 8 . If the authors used this approach, as it seems they did, no clarification is given as to how they propose to standardize the force applied.…”

Transrectal Real-time Tissue Elastography - An Effective Way to Distinguish Benign and Malignant Prostate Tumors

“…Ultrasound elastography is a unique method which combines the advantages of DRE and ultrasound for the assessment of the bioelasticity distribution in vivo by displaying strain images of tissues. Studies have shown that elastography improves the diagnostic effectiveness for prostate cancer (PCa) by compensating for the limitations of DRE, such as the lesion depth and the physician's experience (Miyanaga et al, 2006;Belbase et al, 2013). This technique has been applied widely in the diagnosis of many kinds of tumors.…”