Feature Of The Week 01/25/15: Detection and characterisation of biopsy tissue using quantitative optical coherence elastogaphy (OCE) in men with suspected prostate cancer.
Prostate cancer (PCa) is the most common non-cutaneous malignancy in men. Men suspected with PCa are then offered transrectal ultrasound (TRUS) guided prostate biopsies to confirm the diagnosis, which falls short of making a reliable differentiation between cancer and benign hyperplasia of the gland. Suspected cancerous lesions tend to be stiffer (or harder to feel) than benign tissue. Various elastography modalities such as Ultrasound elastography and MRI elastography are known to have poor spatial resolution, which limits their ability to differentiate small lesions and in identifying early and subtle changes.
OCT is an optical imaging technique that enables high-resolution, cross-sectional imaging of tissue microstructures, in vivo, non-invasive and in real time. Optical coherence elastography (OCE), combines OCT with qualitative or quantitative measurement of tissue stiffness. It has increasingly become attractive, as it carries the potential to provide ultra-high resolution imaging which not only has the ability to detect early and subtle changes but also can characterise tissue based on their mechanical properties (tissue stiffness). The feasibility of characterising and classifying prostatic tissues based on Young’s modulus in kilopascals by using optical coherence elastography (OCE) is not known. This paper reports preliminary results in an ex vivo setting.
A prospective protocol-driven study of 120 consecutive prostatic tissues from 10 men with suspected prostate cancer (PCa). 2D and 3D quantitative mechanical assessment of biopsy specimens obtained in kilopascals (kPa) at interval of 40 µm were compared with histopathology. We assessed the sensitivity, specificity, and positive and negative predictive values of OCE in comparison with histopathological findings. The area under the receiver operating characteristic (ROC) curve and the percentage change in stiffness of core biopsies as measured at each point were compared with the reference standard.
The 3D quantitative mechanical assessment of biopsy specimens obtained in kilopascals (kPa) at intervals of 40 µm significantly compared with histopathology (p < 0.001). OCE imaging could reliably differentiate between benign prostate tissue, acinar atypical hyperplasia, prostatic intraepithelial neoplasia, and malignant PCa. The sensitivity and specificity of OCE for PCa detection was 0.98 and 0.91, respectively, with AUC > 0.99. Quantitative 3D OCE based on the assessment of the mechanical properties of tissues can reliably predict the percentage PCa involvement in core biopsy tissue specimens in an ex vivo setting (p < 0.0002). Further studies combined with advancements in technology are needed to assess and obtain similar information from in vivo settings.
OCE is a reliable technique for characterising prostate tissue in an ex vivo setting. This technique has high diagnostic accuracy, including the ability to predict the percentage involvement of PCa.
For more information see recent Article. Courtesy of Chunhui Li and Ghulam Nabi from University of Dundee.