Technologies for localization and diagnosis of prostate cancer

Evaluation of the Cytotoxic Effect of Pd2Spm against Prostate Cancer through Vibrational Microspectroscopies

Regarding the development of new antineoplastic agents, with a view to assess the selective antitumoral potential which aims at causing irreversible damage to cancer cells while preserving the integrity of their healthy counterparts, it is essential to evaluate the cytotoxic effects in both healthy and malignant human cell lines. In this study, a complex with two Pd(II) centers linked by the biogenic polyamine spermine (Pd₂Spm) was tested on healthy (PNT-2) and cancer (LNCaP and PC-3) prostate human cell lines, using cisplatin as a reference. To understand the mechanisms of action of both cisplatin and Pd₂Spm at a molecular level, Fourier Transform Infrared (FTIR) and Raman microspectroscopies were used. Principal component analysis was applied to the vibrational data, revealing the major metabolic changes caused by each drug, which were found to rely on DNA, lipids, and proteins, acting as biomarkers of drug impact. The main changes were observed between the B-DNA native conformation and either Z-DNA or A-DNA, with a higher effect on lipids having been detected in the presence of cisplatin as compared to Pd₂Spm. In turn, the Pd-agent showed a more significant impact on proteins.

Identification of a distinct luminal subgroup diagnosing and stratifying early stage prostate cancer by tissue-based single-cell RNA sequencing

BACKGROUND

The highly intra-tumoral heterogeneity and complex cell origination of prostate cancer greatly limits the utility of traditional bulk RNA sequencing in finding better biomarker for disease diagnosis and stratification. Tissue specimens based single-cell RNA sequencing holds great promise for identification of novel biomarkers. However, this technique has yet been used in the study of prostate cancer heterogeneity.

METHODS

Cell types and the corresponding marker genes were identified by single-cell RNA sequencing. Malignant states of different clusters were evaluated by copy number variation analysis and differentially expressed genes of pseudo-bulks sequencing. Diagnosis and stratification of prostate cancer was estimated by receiver operating characteristic curves of marker genes. Expression characteristics of marker genes were verified by immunostaining.

RESULTS

Fifteen cell groups including three luminal clusters with different expression profiles were identified in prostate cancer tissues. The luminal cluster with the highest copy number variation level and marker genes enriched in prostate cancer-related metabolic processes was considered the malignant cluster. This cluster contained a distinct subgroup with high expression level of prostate cancer biomarkers and a strong distinguishing ability of normal and cancerous prostates across different pathology grading. In addition, we identified another marker gene, Hepsin (HPN), with a 0.930 area under the curve score distinguishing normal tissue from prostate cancer lesion. This finding was further validated by immunostaining of HPN in prostate cancer tissue array.

CONCLUSION

Our findings provide a valuable resource for interpreting tumor heterogeneity in prostate cancer, and a novel candidate marker for prostate cancer management.

Design and experimental study of a novel 7-DOF manipulator for transrectal ultrasound probe

Traditional hand-held ultrasound probe has some limitations in prostate biopsy. Improving the localization and accuracy of ultrasound probe will increase the detection rate of prostate cancer while biopsy techniques remain unchanged. This paper designs a manipulator for transrectal ultrasound probe, which assists doctors in performing prostate biopsy and improves the efficiency and accuracy of biopsy procedure. The ultrasound probe manipulator includes a position adjustment module that can lock four joints at the same time. It reduces operating time and improves the stability of the mechanism. We use the attitude adjustment module designed by double parallelogram RCM mechanism, the ultrasound probe can realize centering and prevent its radial motion. The self-weight balance design helps doctors operate ultrasound probe without weight. Using MATLAB to analyze the manipulator, the results show that the workspace of the mechanism can meet the biopsy requirements. And simulate the centering effect of the ultrasound probe when the attitude is adjusted at different feeding distances, the results show that the ultrasound probe is centering stability. Finally, the centering and joint interlocking tests of the physical prototype are completed. In this paper, a 7-DOF manipulator for transrectal ultrasound probe is designed. The mechanism is analyzed for kinematics, workspace analysis, simulation of centering effects, development of a physical prototype and related experimental research. The results show that the surgical demand workspace is located inside the reachable workspace of the mechanism and the joint locking of the manipulator is reliable.

A Mechatronic Platform for Computer Aided Detection of Nodules in Anatomopathological Analyses via Stiffness and Ultrasound Measurements

This study presents a platform for ex-vivo detection of cancer nodules, addressing automation of medical diagnoses in surgery and associated histological analyses. The proposed approach takes advantage of the property of cancer to alter the mechanical and acoustical properties of tissues, because of changes in stiffness and density. A force sensor and an ultrasound probe were combined to detect such alterations during force-regulated indentations. To explore the specimens, regardless of their orientation and shape, a scanned area of the test sample was defined using shape recognition applying optical background subtraction to the images captured by a camera. The motorized platform was validated using seven phantom tissues, simulating the mechanical and acoustical properties of ex-vivo diseased tissues, including stiffer nodules that can be encountered in pathological conditions during histological analyses. Results demonstrated the platform’s ability to automatically explore and identify the inclusions in the phantom. Overall, the system was able to correctly identify up to 90.3% of the inclusions by means of stiffness in combination with ultrasound measurements, paving pathways towards robotic palpation during intraoperative examinations.

Value of three-section contrast-enhanced transrectal ultrasonography in the detection of prostate cancer

BACKGROUND

To assess the efficacy of three-section contrast-enhanced transrectal ultrasonography (CETRUS) in prostate cancer (PCa) detection.

METHODS

A total of 169 consecutive patients with either PSA level ≥ 4 ng/ml or abnormal digital rectal examination findings were prospectively enrolled in this single center study. All patients underwent baseline transrectal ultrasonography (TRUS) and three-section CETRUS by one investigator blinded to any clinical data before TRUS-guided transperineal biopsy. The performances of baseline TRUS, single-section, and three-section CETRUS for PCa detection were compared.

RESULTS

On a per-patient basis, the sensitivity, specificity, and overall accuracy for detecting PCa with three-section CETRUS was 92.3%, 69.2%, and 78.1%, respectively. In comparison with conventional (single-section) CETRUS (sensitivity 75.4%, specificity 72.1%, and accuracy 73.4%), three-section CETRUS performed significantly better (p < 0.05, McNemar test). Additionally, the low-grade PCa detection rate for three-section CETRUS was significantly higher than that of conventional CETRUS (26.7% versus 10.2%, p < 0.05).

CONCLUSIONS

Our study demonstrated a significant benefit of three-section CETRUS relative to conventional CETRUS, and this technique may find more PCa patients eligible for active surveillance. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:304-309, 2017.

Role of multiparametric magnetic resonance imaging in early detection of prostate cancer

Abstract

Most prostate cancers (PC) are currently found on the basis of an elevated PSA, although this biomarker has only moderate accuracy. Histological confirmation is traditionally obtained by random transrectal ultrasound guided biopsy, but this approach may underestimate PC. It is generally accepted that a clinically significant PC requires treatment, but in case of an non-significant PC, deferment of treatment and inclusion in an active surveillance program is a valid option. The implementation of multiparametric magnetic resonance imaging (mpMRI) into a screening program may reduce the risk of overdetection of non-significant PC and improve the early detection of clinically significant PC. A mpMRI consists of T2-weighted images supplemented with diffusion-weighted imaging, dynamic contrast enhanced imaging, and/or magnetic resonance spectroscopic imaging and is preferably performed and reported according to the uniform quality standards of the Prostate Imaging Reporting and Data System (PIRADS). International guidelines currently recommend mpMRI in patients with persistently rising PSA and previous negative biopsies, but mpMRI may also be used before first biopsy to improve the biopsy yield by targeting suspicious lesions or to assist in the selection of low-risk patients in whom consideration could be given for surveillance.

Teaching Points

• MpMRI may be used to detect or exclude significant prostate cancer.

• MpMRI can guide targeted rebiopsy in patients with previous negative biopsies.

• In patients with negative mpMRI consideration could be given for surveillance.

• MpMRI may add valuable information for the optimal treatment selection.

Clinical application of sonoelastography in thyroid, prostate, kidney, pancreas, and deep venous thrombosis

This article reviews the clinical applications of current ultrasound elastography methods in non-hepatic conditions including thyroid nodules, prostate cancer, chronic kidney disease, solid renal lesions, pancreatic lesions, and deep vein thrombosis. Pathophysiology alters tissue mechanical properties via ultrastructural changes including fibrosis, increased cellularity, bleeding, and necrosis, creating a target biomarker, which can be imaged qualitatively or quantitatively with US elastography. US elastography methods can add information to conventional US methods and improve the diagnostic performance of conventional US in a range of disease processes.

Modeling the high-frequency complex modulus of silicone rubber using standing Lamb waves and an inverse finite element method

To gain an understanding of the high-frequency elastic properties of silicone rubber, a finite element model of a cylindrical piezoelectric element, in contact with a silicone rubber disk, was constructed. The frequency-dependent elastic modulus of the silicone rubber was modeled by a fourparameter fractional derivative viscoelastic model in the 100 to 250 kHz frequency range. The calculations were carried out in the range of the first radial resonance frequency of the sensor. At the resonance, the hyperelastic effect of the silicone rubber was modeled by a hyperelastic compensating function. The calculated response was matched to the measured response by using the transitional peaks in the impedance spectrum that originates from the switching of standing Lamb wave modes in the silicone rubber. To validate the results, the impedance responses of three 5-mm-thick silicone rubber disks, with different radial lengths, were measured. The calculated and measured transitional frequencies have been compared in detail. The comparison showed very good agreement, with average relative differences of 0.7%, 0.6%, and 0.7% for the silicone rubber samples with radial lengths of 38.0, 21.4, and 11.0 mm, respectively. The average complex elastic moduli of the samples were (0.97 + 0.009i) GPa at 100 kHz and (0.97 + 0.005i) GPa at 250 kHz.

Impact of Real-Time Elastography versus Systematic Prostate Biopsy Method on Cancer Detection Rate in Men with a Serum Prostate-Specific Antigen between 2.5 and 10 ng/mL

The actual gold standard for the diagnosis of prostate cancer includes the serum prostate-specific antigen, the digital rectal examination, and the ultrasound-guided systematic prostate biopsy sampling. In the last years, the real-time elastography has been introduced as an imaging technique to increase the detection rate of prostate cancer and simultaneously reduce the number of biopsies sampled for a single patient. Here, we evaluated a consecutive series of 102 patients with negative digital-rectal examination and transrectal ultrasound, and prostate-specific antigen value ranging between 2.5 ng/mL and 10 ng/mL, in order to assess the impact of real-time elastography versus the systematic biopsy on the detection of prostate cancer. We found that only 1 out of 102 patients resulted true positive for prostate cancer when analysed with real-time elastography. In the other 6 cases, real-time elastography evidenced areas positive for prostate cancer, although additional neoplastic foci were found using systematic biopsy sampling in areas evidenced by real-time elastography as negative. Although additional studies are necessary for evaluating the effectiveness of this imaging technique, the present study indicates that the limited accuracy, sensitivity, and specificity do not justify the routine application of real-time elastography in prostate cancer detection.

A realistic utilization of nanotechnology in molecular imaging and targeted radiotherapy of solid tumors

Precise dose delivery to malignant tissue in radiotherapy is of paramount importance for treatment efficacy while minimizing morbidity of surrounding normal tissues. Current conventional imaging techniques, such as magnetic resonance imaging (MRI) and computerized tomography (CT), are used to define the three-dimensional shape and volume of the tumor for radiation therapy. In many cases, these radiographic imaging (RI) techniques are ambiguous or provide limited information with regard to tumor margins and histopathology. Molecular imaging (MI) modalities, such as positron emission tomography (PET) and single photon-emission computed-tomography (SPECT) that can characterize tumor tissue, are rapidly becoming routine in radiation therapy. However, their inherent low spatial resolution impedes tumor delineation for the purposes of radiation treatment planning. This review will focus on applications of nanotechnology to synergize imaging modalities in order to accurately highlight, as well as subsequently target, tumor cells. Furthermore, using such nano-agents for imaging, simultaneous coupling of novel therapeutics including radiosensitizers can be delivered specifically to the tumor to maximize tumor cell killing while sparing normal tissue.

A fully automatic method to register the prostate gland on T2-weighted and EPI-DWI images

Prostate adenocarcinoma (PCa) is the most frequent noncutaneous cancer among men in developed countries. Magnetic Resonance (MR) has been used to detect PCa and several clinical trials report on the accuracy of the test. Multiparametric MR imaging (mpMRI) is defined as the integration of information from different morphological and functional datasets. mpMRI could be used to increase the performances of prostate MR, therefore allowing a more accurate assessment of the tumor gland extent, while reducing reporting time and interobserver variability. The first step to perform such a multiparametric analysis is to correct for voluntary and involuntary movements during the acquisitions, as well as for image distortion in the Diffusion Weighted (DWI) images. The aim of this work is to present a fully automatic registration algorithm between T2w and DWI images, able to realign the images and to correct the distortions in the DWI. Results showed a good overlap after registration and a strong decrease of mean surface distance in both the central gland and peripheral zone. These promising results suggest that the algorithm could be integrated in a CAD system which will combine the pharmacokinetic parameters derived from DCE-MRI, T2w MRI and DWI MR to generate one comprehensive value assessing the risk of malignancy. However to perform such a multiparametric analysis, it is necessary to correct for voluntary and involuntary (breathing, heart beating) movements during the DCE-MRI acquisition, and to realign also the DCE-MRI sequence to the T2w sequence.