Prostate Cancer Vascularity: Superb Microvascular Imaging Ultrasonography with Histopathology Correlation

Development and validation of a nomogram for predicting prostate cancer based on combining contrast-enhanced transrectal ultrasound and biparametric MRI imaging

Objectives

This study was to explore the feasibility of combining contrast-enhanced transrectal ultrasound (CE-TRUS) with biparametric MRI (CEUS-BpMRI) score for diagnosing prostate cancer (PCa).

Methods

A total of 183 patients with suspected PCa who underwent multiparametric MRI (Mp-MRI) and CE-TRUS were included. CEUS-BpMRI score was developed based on the results of Mp-MRI and CE-TRUS. The diagnostic performance was evaluated by the area under the curve (AUC). The diagnostic efficacy of the CEUS-BpMRI score, BpMRI score, and PI-RADS v2.1 score were compared. Total patients were randomly assigned to a training cohort (70%) or validation cohort (30%). A nomogram was constructed based on univariate and multivariate logistic regression. The model was evaluated by AUC and calibration curve.

Results

The diagnostic performance of CEUS-BpMRI score (AUC 0.857) was comparable to that of PI-RADS v2.1 (AUC 0.862) (P = 0.499), and both were superior to Bp-MRI score (AUC 0.831, P < 0.05). In peripheral zone lesions with Bp-MRI score of 3, there was no statistically significant difference between PI-RADS v2.1 score (AUC 0.728) and CEUS-BpMRI score (AUC 0.668) (P = 0.479). Multivariate analysis showed that age, total prostate specific antigen/free prostate specific antigen (F/T), time to peak (TTP), and CEUS-BpMRI score were independent factors. The AUC of the nomogram was 0.909 in the training cohort and 0.914 in the validation cohort.

Conclusions

CEUS-BpMRI score has high diagnostic efficacy for diagnosing PCa. A nomogram model established by combining age, F/T, TTP, and CEUS-BpMRI score can achieve the best predictive accuracy for PCa.

New microvascular ultrasound techniques: abdominal applications

Microvascular ultrasound (MVUS) is a new ultrasound technique that allows the detection of slow-velocity flow, providing the visualization of the blood flow in small vessels without the need of intravenous contrast agent administration. This technology has been integrated in the most recent ultrasound equipment and applied for the assessment of vascularization. Compared to conventional color Doppler and power Doppler imaging, MVUS provides higher capability to detect intralesional flow. A growing number of studies explored the potential applications in hepatobiliary, genitourinary, and vascular pathologies. Different flow patterns can be observed in hepatic and renal focal lesions providing information on tumor vascularity and improving the differential diagnosis. This article aims to provide a detailed review on the current evidences and applications of MVUS in abdominal imaging.

Detection of relatively poor but definitive blood supply in prostate stromal sarcoma using transrectal ultrasonography with superb microvascular imaging

A 23-year-old man presented with complaints of macrohematuria and hematospermia and was referred to our hospital for further examination. Magnetic resonance imaging revealed a round 30 × 25 mm tumor in the right peripheral zone; hence, a rare prostate tumor was suspected. Grayscale transrectal ultrasonography (TRUS) was performed using the Aplio-i800 PVL-715RST-transducer and revealed a well-defined round tumor. Although regular color Doppler flow imaging could not detect internal blood flow, superb microvascular imaging (SMI) identified the low-velocity blood flow in the tumor. Based on the results of a TRUS-guided targeted biopsy assisted by SMI, the patient was diagnosed with stromal sarcoma. He underwent total pelvic exenteration with construction of ileal conduit and colostomy, the tumor was finally diagnosed as prostate stromal sarcoma (PSS). Since PSS is a rare malignant prostate tumor, reports on the characteristic findings in imaging tests are scarce. To the best of our knowledge, this study reports the first case in which a poor internal blood flow was detected in PSS, but not through regular color Doppler flow imaging. SMI revealed that the blood flow signal to the PSS was relatively poor; however, its definite presence was confirmed, suggesting a malignant disease with relatively poor blood supply and the findings of SMI would assist the adequate targeted biopsy-sampling from the presence site of viable cells with the blood supply.

Microwave for focal therapy of prostate cancer: Non-clinical study and exploratory clinical trial

OBJECTIVE

The objective of this non-clinical study and clinical trial (phase II) was to examine the safety and efficacy of microwave tissue coagulation (MTC) for prostate cancer and assess its use in lesion-targeted focal therapy.

METHODS

In the non-clinical study using Microtaze®-AFM-712 (Alfresa-pharma Corporation) with an MTC-needle, MTC was performed by a transperineal approach to canine prostatic-targeted tissue under real-time ultrasound guidance. Using various MTC-output and irradiation-time combinations, the targeted and surrounding tissues (rectum, bladder, and fat) were examined to confirm the extent of coagulative necrosis or potential cell death, and to compare intra-operative ultrasound and pathology findings. The exploratory clinical trial was conducted to examine the safety and efficacy of MTC. Five selected patients underwent transperineal MTC to clinically single magnetic resonance imaging (MRI)-visible lesions with Gleason score 3+4 or 4+4. Prostate-specific antigen (PSA), MRI, and Expanded Prostate Cancer Index Composite questionnaire findings were compared before and 6 months after surgery.

RESULTS

The region of coagulative necrosis was predictable by monitoring of ultrasonically visible vaporization; thus, by placing the MTC-needle at a certain distance, we were able to perform a safe procedure without adverse events affecting the surrounding organs. Based on the non-clinical study, which used various combinations of both output and irradiation time, MTC with 30-W output for 60-sec irradiation was selected for the prostate. Based on the predictable necrosis, the therapeutic plan (where to place the MTC-needle to achieve complete ablation of the target and how many sessions) was strictly determined per patient. There were no serious adverse events in all patients and only temporary urinary symptoms related to MTC-therapy were observed. Furthermore, satisfaction of having undergone treatment was very high. All pre-operative MRI-visible lesions disappeared, and PSA decreased 55% 6 months after surgery.

CONCLUSION

MTC may be an option for lesion-targeted focal therapy for prostate cancer.

Multiparametric ultrasound and micro-ultrasound in prostate cancer: a comprehensive review

Prostate cancer (PCa) is the most common non-cutaneous cancer diagnosed in males. Traditional tools for screening and diagnosis, such as prostate-specific antigen, digital rectal examination and conventional transrectal ultrasound (TRUS), present low accuracy for PCa detection. Multiparametric MRI has become a game changer in the PCa diagnosis pathway and MRI-targeted biopsies are currently recommended for males at risk of clinically significant PCa, even in biopsy-naïve patients. Recent advances in ultrasound have also emerged with the goal to provide a readily accessible and cost-effective tool for detection of PCa. These newer techniques include elastography and contrast-enhanced ultrasound, as well as improved B-mode and Doppler techniques. These modalities can be combined to define a novel ultrasound approach, multiparametric ultrasound. High frequency Micro-ultrasound has emerged as a promising imaging technology for PCa diagnosis. Initial results have shown high sensitivity of Micro-ultrasound in detecting PCa in addition to its potential in improving the accuracy of targeted biopsies, based on targeting under real-time visualization, rather than relying on cognitive/fusion software MRI-transrectal ultrasound-guided biopsy.

Multiparametric ultrasound of prostate: role in prostate cancer diagnosis

Recent advances in ultrasonography (US) technology established modalities, such as Doppler-US, HistoScanning, contrast-enhanced ultrasonography (CEUS), elastography, and micro-ultrasound. The early results of these US modalities have been promising, although there are limitations including the need for specialized equipment, inconsistent results, lack of standardizations, and external validation. In this review, we identified studies evaluating multiparametric ultrasonography (mpUS), the combination of multiple US modalities, for prostate cancer (PCa) diagnosis. In the past 5 years, a growing number of studies have shown that use of mpUS resulted in high PCa and clinically significant prostate cancer (CSPCa) detection performance using radical prostatectomy histology as the reference standard. Recent studies have demonstrated the role mpUS in improving detection of CSPCa and guidance for prostate biopsy and therapy. Furthermore, some aspects including lower costs, real-time imaging, applicability for some patients who have contraindication for magnetic resonance imaging (MRI) and availability in the office setting are clear advantages of mpUS. Interobserver agreement of mpUS was overall low; however, this limitation can be improved using standardized and objective evaluation systems such as the machine learning model. Whether mpUS outperforms MRI is unclear. Multicenter randomized controlled trials directly comparing mpUS and multiparametric MRI are warranted.

Median Nerve's Microcirculation in Carpal Tunnel Syndrome: Superb Microvascular Imaging

BACKGROUND

The objectivity of physical and electrodiagnostic tests is limited in detecting carpal tunnel syndrome and its recurrence. Predicting the median nerve blood supply using superb microvascular imaging will allow exact diagnosis and a good follow-up system. The aims of this study include using superb microvascular imaging to correlate with electromyographic diagnosis, and to determine the impact of surgery on improvement in superb microvascular imaging.

METHODS

Between July of 2019 and January of 2020, 32 wrists of 21 patients were evaluated prospectively. After preoperative electrodiagnostic studies and vascular index measurement with superb microvascular imaging, open carpal tunnel release was performed by a single surgeon, and 3 months later standardized superb microvascular imaging was performed. Preoperative vascular indexes were compared with the mild, moderate, and severe electrodiagnostic study results. Preoperative and postoperative vascular index results were compared.

RESULTS

The average of the preoperative and postoperative imaging groups was 2.77 and 1.48, respectively, and there was a statistically significant difference between the two groups (p < 0.05). Although no significant difference was found between preoperative and postoperative vascular index values in patients presenting with mild carpal tunnel syndrome (p > 0.05), there was a significant decrease in vascular index values in patients presenting with moderate and severe carpal tunnel syndrome after surgical decompression.

CONCLUSIONS

Superb microvascular imaging is emerging as a groundbreaking, new, and reliable technique. Evaluation of the median nerve blood supply is a reliable method that would be helpful for early diagnosis, planning treatment, determining the severity of carpal tunnel syndrome, and postoperative follow-up.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Diagnostic, IV.

Superb microvascular imaging in guiding targeted biopsy of prostate cancer: A protocol for systematic review and meta analysis

BACKGROUND

Studies suggested superb microvascular imaging technology to guide prostate cancer biopsy could improve the positive rate of draw materials. The present meta-analysis aimed at determining the accuracy of SMI in the location diagnosis for prostate cancer.

METHODS

We will search PubMed, Web of Science, Cochrane Library, and Chinese biomedical databases from their inceptions to the October 31st, 2020. Two authors will independently carry out searching literature records, scanning titles and abstracts, full texts, collecting data, and assessing risk of bias. Review Manager 5.2 and Stata14.0 software will be used for data analysis.

RESULTS

This systematic review will determine the accuracy of superb microvascular imaging in guiding targeted biopsy of prostate cancer.

CONCLUSION

Its findings will provide helpful evidence for the accuracy of superb microvascular imaging in guiding targeted biopsy of prostate cancer.

SYSTEMATIC REVIEW REGISTRATION

INPLASY2020100117.

Efficacy of superb microvascular imaging of ultrasound for diagnosis of gallbladder lesion

BACKGROUND/PURPOSE

The diagnosis of gallbladder (GB) lesions is occasionally difficult. Recently, superb microvascular imaging (SMI) of ultrasound has been developed as a novel microvascular imaging technique. We evaluated the feasibility of SMI for the diagnosis of GB lesions and compared microvascular imaging between benign and malignant GB lesions.

METHODS

Twenty patients with GB-protruded lesions or wall thickening who underwent SMI from August 2015 to July 2017 were included in this retrospective study. The measured outcomes were the quality of microvascular imaging when compared between normal SMI (N-SMI) and contrast-enhanced SMI (CE-SMI), and the microvascular findings (vascularity, vascular morphology, presence of branching, and presence of caliber change) when compared between benign and malignant GB lesions.

RESULTS

The quality of microvascular imaging of CE-SMI was evaluated as better than that of N-SMI, showing a significant difference (P < .001). From the CE-SMI microvascular findings, the evaluation of vascular morphology and the presence of caliber change showed a significant difference between benign and malignant GB lesions (P = .005, P < .001).

CONCLUSIONS

The evaluation of GB lesions using SMI was feasible with a contrast agent. Vascular morphology and the presence of caliber change may help in the differential diagnosis of GB lesions.

PSA Based Biomarkers, Imagistic Techniques and Combined Tests for a Better Diagnostic of Localized Prostate Cancer

Prostate cancer represents the most encountered urinary malignancy in males over 50 years old, and the second most diagnosed after lung cancer globally. Digital rectal examination and prostatic specific antigen were the long-time standard tools for diagnosis but with a significant risk of overdiagnosis and overtreatment. Magnetic resonance imaging recently entered the diagnosis process, but to this date, there is no specific biomarker that accurately indicates whether to proceed with the prostate biopsy. Research in this area has gone towards this direction, and recently, serum, urine, imagistic, tissue biomarkers, and Risk Calculators promise to help better diagnose and stratify prostate cancer. In order to eliminate the comorbidities that appear along with the diagnosis and treatment of this disease, there is a constant need to implement new diagnostic strategies. Important uro-oncology associations recommend the use of novel biomarkers in the grey area of prostate cancer, to better distinguish the next step in the diagnostic process. Although it is not that simple, they should be integrated according to the clinical policies, and it should be considered that statistical significance does not always equal clinical significance. In this review, we analyzed the contribution of prostate-specific antigen (PSA)-based biomarkers (PHI, PHID, 4Kscore, STHLM3), imagistic techniques (mp-MRI and mp-US), and combined tests in the early diagnosis process of localized prostate cancer.