Institute for Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh, UK.
Department of Urology, Western General Hospital, Edinburgh, UK.
Proc Inst Mech Eng H. 2023 May;237(5):571-584. doi: 10.1177/09544119231154305. Epub 2023 Apr 16.
A calibrated palpation sensor has been developed for making instrumented Digital Rectal Examinations (iDREs) with a view to assessing patients for prostate cancer. The instrument measures the dynamic stiffness of the palpable surface of the prostate, and has been trialled on 12 patients in vivo. The patients had been diagnosed with prostate cancer and were scheduled for radical prostatectomy. As far as possible, patients with asymmetric disease were chosen so as to give a variation in gland condition over the palpable surface. The device works by applying an oscillating pressure (force) to a flexible probe whose displacement into the tissue is also measured in order to yield a dynamic stiffness, the static stiffness being incidentally measured at the mean oscillatory force. The device was deployed mounted on the index finger of a urologist and measurements taken at 12-16 positions on each patient using light and firm pressure and palpation frequencies of 1 or 5 Hz. In parallel, conventional DRE assessments were made by a consultant urologist for cancer. After in vivo measurement, the glands were removed and examined histologically with each palpation point being classified as cancerous (C) or not (NC). The work has established the first measurements of static modulus of living prostate tissue to be: 26.8 (13.3) kPa for tissue affected by prostate cancer (C classification), and 24.8 kPa (11.9) for tissue unaffected by cancer (NC classification), values quoted as median (interquartile range). The dynamic properties were characterised by: dynamic modulus, 5.15 kPa (4.86) for the C classification and 4.61 kPa (3.08) for the NC classification and the time lag between force and displacement at 5 Hz palpation frequency, 0.0175 s (0.0078) for the C classification and 0.0186 s (0.0397) for the NC classification, values again quoted as median (interquartile range). With the limited set of features that could be generated, an Artificial Neural Network (ANN) classification yielded a sensitivity of 97%, negative predictive value of 86%, positive predictive value of 67% and accuracy of 70% but with relatively poor specificity (30%). Besides extending the feature set, there are a number of changes in probe design, probing strategy and in mechanics analysis, which are expected to improve the diagnostic capabilities of the method.
一种校准触诊传感器已被开发出来，用于进行仪器化数字直肠检查（iDRE），以便对前列腺癌患者进行评估。该仪器测量可触及前列腺表面的动态刚度，并已在 12 名体内患者中进行了试验。这些患者被诊断患有前列腺癌，并计划接受根治性前列腺切除术。尽可能选择患有不对称性疾病的患者，以使可触及表面的腺体状况有所不同。该设备通过向柔性探头施加振荡压力（力）来工作，该探头的位移也被测量以产生动态刚度，静态刚度偶然地在平均振荡力下测量。该设备安装在泌尿科医生的食指上，并使用轻压和重压以及 1 或 5 Hz 的触诊频率，在每个患者的 12-16 个位置进行测量。同时，由顾问泌尿科医生对癌症进行常规 DRE 评估。在体内测量后，将腺体切除并进行组织学检查，每个触诊点被分类为癌性（C）或非癌性（NC）。这项工作首次测量了活体前列腺组织的静态模量，结果为：受前列腺癌影响的组织为 26.8（13.3）kPa（C 分类），未受癌症影响的组织为 24.8 kPa（11.9）kPa（NC 分类），引用中位数（四分位距）。动态特性的特征为：C 分类的动态模量为 5.15 kPa（4.86），NC 分类的动态模量为 4.61 kPa（3.08），5 Hz 触诊频率下力与位移之间的时滞为 0.0175 s（0.0078），C 分类为 0.0186 s（0.0397），再次引用中位数（四分位距）。使用可以生成的有限特征集，人工神经网络（ANN）分类的灵敏度为 97%，阴性预测值为 86%，阳性预测值为 67%，准确率为 70%，但特异性相对较差（30%）。除了扩展特征集之外，还需要对探头设计、探测策略和力学分析进行一些更改，这有望提高该方法的诊断能力。
