Shear wave elastography as a new, non-invasive diagnostic modality for the diagnosis of penile elasticity: a prospective multicenter study

Glans penis volume is associated with lifelong premature ejaculation

BACKGROUND

Although premature ejaculation (PE) is the most common male sexual dysfunction, the underlying mechanisms are not fully understood.

AIM

The study sought to evaluate the possible associations among glans penis volume and tissue stiffness measured using penile ultrasonography and penile shear wave elastography (SWE) with PE.

METHODS

Men 18 to 65 years of age with normal International Index of Erectile Function scores (>25) and who were diagnosed with PE between June 2021 and June 2022 were enrolled. The Premature Ejaculation Diagnostic Tool score and intravaginal ejaculation latency times were recorded. Healthy volunteers constituted the control group. The study group was divided into lifelong PE (LLPE) and acquired PE (AqPE) subgroups. In all groups, the glans penis volume was measured via penile ultrasonography and tissue stiffness of the glans penis, penile frenulum, postcircumcision mucosal cuff, and penile shaft were measured via SWE. The findings of the groups were compared using appropriate statistical methods.

OUTCOMES

The outcomes included ultrasonographic and elastographic measurements of the glans penis.

RESULTS

Data on 140 men, including 70 PE patients and 70 healthy volunteers, were evaluated. Of the patients, 20 had LLPE and 50 had AqPE. The median glans penis volume was significantly greater in the LLPE group (14.1 [range, 6.6-19] mm3) compared with the AqPE group (11.7 [range, 5.1-27] mm3) and control group (11.4 [range, 6.1-32] mm3) (P = .03). According to the Youden index, the best cutoff value for glans penis volume in LLPE compared with non-LLPE (AqPE + control) was 12.65 mm3 (area under the curve, 0.684; 95% confidence interval, 0.556-0.812; P = .009). The risk of having LLPE in those with a glans penis volume ≥12.65 mm3 was 3.326 (95% confidence interval, 1.234-8.965) times higher than the non-LLPE group (P = .014). There were no significant differences between the groups in the SWE evaluation of glans penis, penile frenulum, mucosal cuff, and penile shaft tissue stiffness.

CLINICAL IMPLICATIONS

The high incidence of PE in those with high glans penis volume may make glans penis volume a predictor for the development of LLPE.

STRENGTHS AND LIMITATIONS

This was the first study to show that PE is more common in individuals with a high glans penis volume. It was also the first to perform a penile elastographic evaluation in patients with PE. The most important limitation was that we did not evaluate glans penile nerve function with a test, but rather we made an indirect inference about the density of free nerve endings based on increased glans penile volume.

CONCLUSION

Glans penis volume was a significant predictor for LLPE. However, there are no associations between PE and the glans penis, postcircumcision mucosal cuff, penile frenulum, or penile shaft tissue stiffness and development.

Myofibroblasts: A New Factor Affecting the Hyperlipidemia-Induced Elastic Abnormality of Corpus Cavernosum in Rabbits Detected by 2-D Shear Wave Elastography

OBJECTIVE

Two-dimensional shear wave elastography (2-D SWE) has been proven to detect hyperlipidemia-induced elastic abnormality in the corpus cavernosum. This study investigated cytological factors affecting the elasticity of the corpus cavernosum in rabbits with hyperlipidemia using single-cell RNA sequencing (scRNA-seq).

METHODS

Male New Zealand white rabbits were randomly divided into a hyperlipidemia group (high-cholesterol diet) and a control group (standard diet). Penile 2-D SWE was performed to detect the elastic abnormality in the corpus cavernosum. ScRNA-seq was performed to observe cellular changes in the corpus cavernosum of rabbits with hyperlipidemia. Immunohistochemistry, immunofluorescence and histological examinations were conducted to verify the results of scRNA-seq.

RESULTS

Two-dimensional SWE revealed that the Young's modulus of the corpus cavernosum was significantly greater in the hyperlipidemia group than that in the control group (p < 0.001). Histological findings revealed extracellular matrix accumulation within the corpus cavernosum, with stronger staining of collagen types I and Ⅲ. ScRNA-seq revealed that fibroblasts, smooth muscle cells, and endothelial cells were the major cell types in the corpus cavernosum. A novel subtype of fibroblasts (myofibroblast) was discovered in the hyperlipidemia group, which was verified by immunofluorescence staining and gene ontology analysis. Fibroblasts, smooth muscle cells and endothelial cells were three cellular sources for myofibroblasts.

CONCLUSION

Myofibroblasts are activated and proliferate and secrete large amounts of collagen fibers in the corpus cavernosum during hyperlipidemia, leading to abnormal Young's modulus detected by 2-D SWE and their recognition as a new factor affecting the hyperlipidemia-induced elastic abnormality of the corpus cavernosum.

Comparison of preoperative penile elastographic ultrasound findings and pathological tissue results of patients implemented with penile prosthesis

OBJECTIVE

Histopathological analysis of the relationship between penile elastography and erectile dysfunction.

MATERIAL AND METHOD

12 patients who applied to our clinic for erectile dysfunction in the last 1 year and accepted this study were included. Preoperative two-dimensional shear wave elastography imaging was performed in 12 patients and recorded in the Pascal (kPa) unit. Approximately 0.5 × 0.5 × 0.5 cm tissue samples were taken from the right and left cavernous tissue during penile prosthesis implantation operation. Tissue samples were sent to the pathology department. The percentage of the area covered by muscle fibers and elastic fibers in the corpus cavernosum was noted semi-quantitatively (ratio of muscle fibers and cavernous body elastic fiber score). All data obtained were compared with each other.

RESULTS

Cavernous body elastic fiber score data(Grouped Score 1, 2 and 3) and percentage of cavernous body muscle fibers data (Grouped %10, %20, %30… %100) were compared with Shear wave elastography data (kPa). The results were not statistically significant according to the Kruskal Wallis Test. Cavernous body elastic fiber score and the percentage of cavernous body muscle fibers were also compared, it was not statistically significant according to the Kruskal Wallis test and Spearman's correlation test.

CONCLUSIONS

Penile shear wave elastography can be used clinically to quantitatively assess the amount of smooth muscle cells and elastic fibers in the penis, but it deserves to be studied with a larger number of patients and a more specific interpretation of the pathology preparation.

Sexual dysfunction therapeutic approaches in patients with multiple sclerosis: a systematic review

OBJECTIVE

Multiple sclerosis (MS) is the most common chronic inflammatory demyelinating disease of the central nervous system (CNS). The most common clinical manifestations of MS are spasticity, pain, vesico-urethral disorders, cognitive impairments, chronic fatigue and sexual dysfunction. This review aims to explore the possible therapeutic options for managing sexual dysfunction in people with MS (PwMS).

METHOD

A thorough search of the PubMed Medline database was performed. Records were limited to clinical studies published between 01/01/2010 up to 01/01/2022. The results were screened by the authors in pairs.

RESULTS

The search identified 36 records. After screening, 9 records met the inclusion-exclusion criteria and were assessed. The pharmacological approaches investigated the effectiveness of sildenafil, tadalafil and onabotulinumtoxinA. Of the interventional studies the non-pharmacological investigated, the effectiveness of aquatic exercises, the application of pelvic floor exercises,the combination of pelvic floor exercises and mindfulness technique, the combination of pelvic floor exercises and electro muscular stimulation with electromyograph biofeedback, the application of yoga techniques and the efficacy of assistive devices like the clitoral vacuum suction device and the vibration device.

CONCLUSION

The management of sexual dysfunction in PwMS needs to be further investigated. A team of healthcare professionals should be involved in the management of SD in order to address not only the primary (MS-related) SD symptoms but the secondary and tertiary as well. The main limitations that were identified in the existing literature were related to MS disease features, sample characteristics and evaluation tools and batteries.

Factors affecting the shear wave elastic quantitative measurement of penile tissue in rats

Background

As a new ultrasound technology, 2-dimensional shear wave elastography (2D-SWE) can evaluate the elastic characteristics of penile tissue. However, no studies have reported the main factors affecting the shear wave elastic quantitative measurement (SWQ) in penile tissue.

Objectives

To analyze the main factors affecting the SWQ reflecting the elastic characteristics of penile tissue by 2D-SWE.

Methods

Twenty healthy male Sprague-Dawley rats (5-60 weeks old) were selected for this study. We performed the 2D-SWE examination on the penis using the Aixplorer ultrasound system, with SWQ as the measurement index. We performed penile immunohistochemistry analysis with the positive area proportion (PAP) of alpha-smooth muscle actin (PAPS) and type III collagen fiber (PAPC) as the outcomes. Then, we conducted multiple linear regression analysis to explore the correlation of SWQ with PAPS and PAPC and established the regression equation.

Results

The multiple linear regression analysis showed that the linear regression equation (SWQ = 10.376 - 0.05 PAPS - 0.07 PAPC) was statistically significant (F = 21.153, P < 0.001). The content of smooth muscle cells (SMCs) and collagen fibers was negatively correlated with SWQ, affecting 42.6% of the total variation in SWQ (R2 = 0.426).

Conclusions

SMCs and collagen fibers are the main factors affecting the SWQ value of penile tissue and the primary tissue components determining the SWQ when using 2D-SWE to quantitatively evaluate the elastic characteristics of penile tissue.

Association between urethral funneling in stress urinary incontinence and the biological properties of the urethral rhabdosphincter muscle based on shear wave elastography

OBJECTIVES

To apply shear wave elastography (SWE) combined with transperineal ultrasonography (TPUS) to study the association between urethral funneling in stress urinary incontinence (SUI) and the biological properties of the urethral rhabdosphincter muscle in women.

METHODS

This single-center retrospective study included 166 women with SUI (SUI group) and 185 women who underwent a routine physical examination (control group). The control group and SUI group were divided into nonfunneling and funneling groups according to the presence or absence of urethral funneling, respectively, and their ultrasound findings were compared to analyze the association between funneling and ultrasound measurements.

RESULTS

The SUI group had a lower mean E than the control group (15.54 vs. 20.82 kPa, p < 0.001). The SUI-funneling group had a lower mean E than the SUI-nonfunneling group (15.50 vs. 17.21 kPa, p < 0.001). The area under the (AUC) receiver operating characteristic (ROC) curve of the mean E for predicting SUI was 0.864, with a cutoff value of 19.19 kPa. The AUC of the mean E for predicting urethral funneling was 0.832, with a cutoff value of 17.15 kPa. The stiffness of the urethral rhabdosphincter was an independent factor related to SUI and urethral funneling in SUI.

CONCLUSIONS

SWE can be used to assess the biological properties of the urethral rhabdosphincter, and reduced stiffness of the rhabdosphincter was significantly correlated with SUI and funneling in SUI. Thus, women with urethral funneling in SUI may have a weak urethral rhabdosphincter.

Wearable Soft Microtube Sensors for Quantitative Home-Based Erectile Dysfunction Monitoring

Quantifiable erectile dysfunction (ED) diagnosis involves the monitoring of rigidity and tumescence of the penile shaft during nocturnal penile tumescence (NPT). In this work, we introduce Erectile Dysfunction SENsor (EDSEN), a home-based wearable device for quantitative penile health monitoring based on stretchable microtubular sensing technology. Two types of sensors, the T- and R-sensors, are developed to effectively measure penile tumescence and rigidity, respectively. Conical models mimicking penile shaft were fabricated with polydimethylsiloxane (PDMS) material, using different base to curing agent ratios to replicate the different hardness properties of a penile shaft. A theoretical buckling force chart for the different penile models is generated to determine sufficiency criteria for sexual intercourse. An average erect penile length and circumference requires at least a Young's modulus of 179 kPa for optimal buckling force required for satisfactory sexual intercourse. The conical penile models were evaluated using EDSEN. Our results verified that the circumference of a penile shaft can be accurately measured by T-sensor and rigidity using the R-sensor. EDSEN provides a private and quantitative method to detect ED within the comfortable confines of the user's home.

Use of penile shear wave elastosonography for the diagnosis of Peyronie's Disease: a prospective case-control study

BACKGROUND

To evaluate the stiffness of the tunica albuginea (TA), we used a new noninvasive diagnostic technique called shear wave elastography (SWE). We determined whether SWE values are correlated with the degree of penile curvature, the time of disease onset, and pain severity experienced by patients during erection. This study analyzed the elasticity of the TA of patients with Peyronie's disease compared to that of the control group. We also analyzed any correlations between the stiffness of the cavernous bodies and the degree of curvature, time from diagnosis to curvature onset, and erectile pain severity. This was a prospective case-control study involving 100 men enrolled from September 2020 to August 2021. Participants were divided into group A (case group, n = 50), which included men with PD, with or without pain, and with penile curvature, or group B (control group, n = 50), which included healthy patients older than 18 years who visited the urology clinic for reasons other than PD. The medical history was collected for all patients who also underwent objective examination, B-mode ultrasound evaluation, and SWE. The International Index of Erectile Function (IIEF-15) visual analog scale (VAS) questionnaire was administered to all participants.

RESULTS

There were no significant between-group differences regarding age, weight, and height (p > 0.05); however, there was a significant difference in the stiffness values (p < 0.05). An inverse correlation was observed between stiffness and the VAS score (p < 0.0001). A positive correlation was observed between the degree of curvature (p < 0.0001) and the time of curvature onset (p < 0.0001). The IIEF-15 scores were poorer in group A than in group B (p < 0.0001).

CONCLUSION

SWE is an inexpensive, noninvasive method that can be used to measure the stiffness of PD patients.

Elastography in the Urological Practice: Urinary and Male Genital Tract, Prostate Excluded—Review

The aim of this article is to review the utility of elastography in the day-to-day clinical practice of the urologist. An electronic database search was performed on PubMed and Cochrane Library with a date range between January 2000 and December 2021. The search yielded 94 articles that passed the inclusion and exclusion criteria. The articles were reviewed and discussed by organ, pathology and according to the physical principle underlying the elastographic method. Elastography was used in the study of normal organs, tumoral masses, chronic upper and lower urinary tract obstructive diseases, dysfunctions of the lower urinary tract and the male reproductive system, and as a pre- and post-treatment monitoring tool. Elastography has numerous applications in urology, but due to a lack of standardization in the methodology and equipment, further studies are required.

Pathophysiology and Grayscale Ultrasonography of Penile Corporal Fibrosis

INTRODUCTION

Penile corporal fibrosis may occur secondary to explantation of an infected penile prosthesis, severe penile trauma, refractory low-flow priapism, Peyronie's disease, or chronic intra-cavernous injection of vasoactive drugs. Other etiologies of corporal fibrosis, presenting primarily with erectile dysfunction, can develop in chronic smokers, hypertensive patients, alcoholics, diabetics, and after radical prostatectomy. Corporal erectile tissue fibrosis is a significant pathophysiologic component of erectile dysfunction; however, current ultrasound-based penile imaging protocols do not directly assess it.

OBJECTIVE

To determine if grayscale ultrasonography (US) is a suitable imaging modality to identify and assess penile corporal erectile tissue fibrosis.

METHODS

A PubMed literature review was performed for studies that detailed ultrasonographic methods and findings of pathologies causing penile corporal fibrosis. Our main outcome measure was the ultrasonographic findings of pathologies causing penile corporal fibrosis.

RESULTS

Grayscale US demonstrates the capability to detect and localize the fibrotic changes of the corpora cavernosa. Ultrasonographic findings capture penile corporal tissue heterogeneity including diffuse, circumscribed, or localized patterns.

CONCLUSION

Overall, grayscale US may be a useful and convenient imaging modality to assess penile corporal fibrosis secondary to explantation of an infected penile prosthesis, priapism, penile trauma, chronic intra-cavernous injection of vasoactive drugs, diabetes, Peyronie's disease, and vascular disease. While limited by the skill and knowledge of the US operator, the combined knowledge of pathophysiology and US may help clinicians identify and manage the underlying etiology of penile corporal fibrosis. Kim J, Drury R, Morenas R et al. Pathophysiology and Grayscale Ultrasonography of Penile Corporal Fibrosis. Sex Med Rev 2022;10:99-107.

Testicular shear wave elastography in oligo-astheno-teratozoospermic individuals: a prospective case-control study

Purpose

The primary objective of this study was to evaluate the testicular stiffness by ultrasound shear wave elastography (SWE) both in men with oligo-astheno-teratozospermia (OAT) and in control group. The secondary objective was to identify a possible correlation between semen quality with testicular stiffness.

Methods

This was a prospective case-control study. We divided the sample in two groups; Group A (case group) included men with OAT, and Group B (control group) men with normal sperm parameters. All participants had at last two semen analysis in the past 180 days (at last 90 days apart), using performed ultrasound and SWE elastography.

Results

We analyzed 100 participants, 50 patients in Group A and 50 controls in Group B. There were statistically significant differences in term of testicular volume and testicular stiffness between two groups. Men with OAT had the testicular stiffness value higher than the controls in both sides (left testicular stiffness 21.4 ± 5.4 kPa vs 9.9 ± 1.6 kPa, p < 0.0001; right testicular stiffness 22.9 ± 4.8 kPa vs 9.5 ± 2.4 kPa, p < 0.0001). Men with abnormal semen parameters showed an inverse correlation between the mean value of testicular stiffness and total sperm count (22.15 ± 3.38 kPa, r = − 0.387, p = 0.005), sperm concentration (22.15 ± 3.38 kPa, r = − 0.244, p = 0.04), and progressive motility (22.15 ± 3.38 kPa, r = − 0.336, p = 0.01), while the correlation was not evident in controls group.

Conclusion

SWE is able to differentiate between testicles with spermatogenic changes from a healthy testicle. For this reason, it could be used to evaluate, in a non-invasive way, the tissue alterations of the organ.