The role of shear wave elastography on evaluation of the rigidity changes of corpus cavernosum penis in venogenic erectile dysfunction

The value of shear wave elastography combined with red blood cell distribution width in evaluating arterial erectile dysfunction

PURPOSE

A retrospective study was conducted to determine the value of shear wave elastography (SWE) and red blood cell distribution width (RDW) in the diagnosis of various forms of erectile dysfunction (ED).

METHODS

With the method of Nocturnal Penile Tumescence and Rigidity (NPTR) and the screening method of Color Duplex Doppler Ultrasound (CDDU), hematological data were collected from 131 individuals, among whom 24 are with psychogenic ED, 48 are with non-arterial ED(NAED) and 59 are with arterial ED(AED) with erectile dysfunction. SWE value of penile corpus cavernosum(CCP) and cavernous arterial flow velocity were measured before (flaccid state) and after (erect state) intracavernous injection (ICI) in all patients.

RESULTS

Among the AED patients and other types of ED patients, there were statistically significant differences in the abridged five-item International Index of Erectile Function (IIEF-5), red blood cell distribution width-coefficient of variation (RDW-CV), red blood cell distribution width-standard deviation (RDW-SD), and SWE values (all P < 0.01). In the AED patients, the IIEF-5 scores had a significant negative relationship with RDW-CV, RDW-SD, and SWE values, with SWE values having the strongest correlation. (p < 0.001, r=-0.638).

CONCLUSION

The combination of RDW level and SWE value demonstrated the greatest performance in diagnosing AED, according to the receiver-operator characteristic(ROC) curve analysis (AUC = 0.870, p < 0.0001, cut-off value of 0.75, sensitivity of 74.6%, specificity of 91.7%).RDW and SWE value may develop into an incredibly simple, practical tool for predicting and diagnosing AED.

TRIAL REGISTRATION

retrospectively registered.

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.

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.

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.

Contribution of UltraFast™ Ultrasound and Shear Wave Elastography in the Imaging of Carotid Artery Disease

Carotid artery disease is one of the main global causes of disability and premature mortality in the spectrum of cardiovascular diseases. One of its main consequences, stroke, is the second biggest global contributor to disability and burden via Disability Adjusted Life Years after ischemic heart disease. In the last decades, B-mode and Doppler-based ultrasound imaging techniques have become an indispensable part of modern medical imaging of carotid artery disease. However, they have limited abilities in carotid artery plaque and wall characterization and are unable to provide simultaneous quantitative and qualitative flow information while the images are burdened by low framerates. UltraFast™ ultrasound is able to overcome these obstacles by providing simultaneous quantitative and qualitative flow analysis information in high frame rates via UltraFast™ Doppler. Another newly developed ultrasound technique, shear wave elastography, is based on the visualization of induced shear waves and the measurement of the shear wave propagation speed in the examined tissues which enables real-time carotid plaque and wall analysis. These newly developed ultrasound modalities have potential to significantly improve workflow efficiency and are able to provide a plethora of additional imaging information of carotid artery disease in comparison to conventional ultrasound techniques.

Assessment of the Rigidity Changes of Corpus Cavernosum Penis in Vasculary Erectile Dysfunction (ED) Subtypes by Shear Wave Elastography (SWE)

INTRODUCTION

Erectile dysfunction (ED) is a condition that is very common all over the world, concerns about men and causes very important social problems. The aim of this study is to perform quantitative penile corpus cavernosum (CC) stiffness measurements by using SWE for patients with both types of vascular ED.

METHODS

In our study, we handled the data of 101 participants in total. The average age of the participants was 56.36. We divided the participants after color Doppler US (CDUS) into three groups: normal group (n = 30), arterial insufficiency (n = 51), and venous insufficiency (n = 20). SWE measurements were made in both groups in the CC flaccid (f) and rigid (r) positions, and the results were noted. International Index of Erectile Function (IIEF-5) questionnaire and Erection score (ES) were evaluated.

RESULTS

The mean CC f SWE and r SWE measurement values were 20.2 ± 0.8 and 17.15 ± 0.54 kPa, 3.84 ± 0.13 and 2.78 ± 0.11 m/s in the arterial insufficiency group; 15.72 ± 0.58 and 12.52 ± 0.33 kPa, 2.88 ± 0.06 and 2.09 ± 0.11 m/s in the venous insufficiency group; 14.75 ± 0.51 and 13.41 ± 0.36 kPa, 2.63 ± 0.1 and 2.34 ± 0.11 m/s in the control group, respectively. The CC measurement of f SWE and r SWE values as kPa showed significant differences between the groups (P < .001).

CONCLUSION

SWE can provide quantitative data with high specificity and sensitivity while evaluating CC penile stiffness noninvasively. It seems to contribute to the radiological evaluation of ED cases with useful data.

Role of shear wave elastography (SWE) in erectile dysfunction patients for evaluation of daily tadalafil treatment outcome

The purpose of this study was to evaluate and anticipate the outcome of daily use of tadalafil in patients with erectile dysfunction using elastography. 183 volunteers and 183 patients with erectile dysfunction were included. Pretreatment SWE readings for our patients were calculated with a linear probe. IIEF score Q was measured once at the start of the study for volunteers and twice for patients, one prior to the start of tadalafil administration and the other on one year of 5 mg daily tadalafil after the second post-washout (one month post-treatment stopped). There was no significant difference between patients and volunteers in mean age or risk factors except in SWE values as mean SWE of volunteers was 14.03 ± 1.54 kpasc, while mean SWE of patients was 21.278 ± 8.228 kpasc. The presence of comorbid diabetes, severe disease and pre-SWE ≥23.635 was significantly associated with poor outcome. We conclude that penile SWE could be useful to select probable good responders for a continuous tadalafil use, thus avoiding the unnecessary cost and time in non-responders.

Evaluation of Arterial Erectile Dysfunction Using Shear Wave Elastography: A Feasibility Study

OBJECTIVES

To explore the feasibility of shear wave elastography (SWE) in the evaluation of arterial erectile dysfunction (ED).

METHODS

From November 2018 to November 2019, 26 patients with arterial ED and 30 patients with non-vascular ED were prospectively included. SWE values of corpus cavernosum penis (CCP) and the flow velocity of cavernous artery for all patients in both before intracavernous injection (ICI) (flaccid state) and after ICI (erectile state) were measured. Performance of SWE value in assessing arterial ED was studied. Correlation between SWE value of CCP and the age of patients was also investigated.

RESULTS

ICI significantly reduced SWE values in both arterial and non-vascular group (from 19.57 ± 6.33 KPa to 12.17 ± 3.64 KPa in the first, and from 19.91 ± 6.69 KPa to 8.04 ± 3.13 KPa in the former, both P < .001). SWE values of CCP after ICI in arterial ED were significantly larger than that in non-vascular ED (P < .001). SWE values of CCP before ICI negatively correlated with age of patients in arterial ED (r = - 0.601, P < .001). With a cutoff value of 7.75 KPa, the area under curve, specificity, sensitivity, PPV, and NPV of SWE values of CCP after ICI in distinguishing arterial ED from non-vascular ED were 0.810, 63.3%, 96.2%, 96.2%, and 70%, respectively.

CONCLUSIONS

SWE was expected to be a potential technique for the noninvasive, simply operated, repeatable and quantitative evaluation of arterial ED.

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

Objective:

Shear wave elastosonography (SWE) could be used to evaluate the elasticity of penile tissue. Few studies in the literature, however, have investigated its use in patients with erectile dysfunction (ED) or have attempted to correlate findings with International Index of Erectile Function (IIEF-5) scores. The primary aim of this study was to evaluate the characteristics of erectile tissue using SWE and to determine possible relationships with IIEF-5 and Erection Hardness Scale (EHS) scores. The secondary aim was to establish a cut-off SWE examination value over which cavernous tissue stiffness could contribute to a subsequent organic alteration.

Methods:

This prospective study included male patients 18−80 years of age who attended two general andrology clinics and underwent SWE. Subjects were divided into groups according to IIEF-5 score, and correlations between SWE and IIEF-5 and EHS questionnaire scores were explored.

Results:

A total of 270 subjects (mean age 46.7 ± 16.9 years) were included. ED was reflected by low IIEF-5 and EHS scores and a decrease in the mean elasticity of the corpora cavernosa according to SWE, although the difference between the left and right corpora cavernosa was not statistically significant. No statistically significant correlation was found between measurements of the corpora cavernosa (in kPa) and age. The optimal cut-off identified was 24.75 kPa.

Conclusion:

Results demonstrated that the mean elasticity of the corpora cavernosa according to SWE was correlated with IIEF-5 score and EHS score.

Role of shear wave elastography measured in the flaccid state in predicting arteriogenic erectile dysfunction

The gold-standard method for diagnosing arteriogenic erectile dysfunction (AED) is the penile Doppler ultrasonography. We proposed a novel method for predicting AED using ultrasonic shear wave elastography (SWE) considering that the former was invasive and variable. A total of 98 male patients were enrolled in our study, referred for ED between December 2018 and October 2020. For comparison, we also included 42 volunteers from the Healthy Physical Examination Center of our hospital. The Penile Doppler Ultrasonography (PDU) and SWE were performed for all patients with the intracavernosal injection (ICI). We named three groups as AED group, nonvascular ED group and healthy controls group. No statistically significant differences were found among the three groups in terms of demographic and clinical characteristics. There were no significant differences in IIEF-5 between AED and nonvascular ED. A significant (r = 0.642, p < 0.0001) positive correlation between flaccid and erectile SWE was observed. With a cut-off value of 13.45 KPa, the area under curve, specificity, and sensitivity of the SWE values under the flaccid state in distinguishing AED from healthy subjects were 0.867, 0.786 and 0.896 respectively. The SWE value in the flaccid state can distinguish the AED from healthy subjects.

Current approaches to the diagnosis of vascular erectile dysfunction

Vascular erectile dysfunction (ED) is closely related to cardiovascular events, and early diagnosis of vascular ED may be helpful to predict the occurrence of cardiovascular events and improve prognosis. At present, there are many approaches to diagnose ED, but each method has its advantages and limitations. This study retrospectively reviewed all available literature focusing on the diagnosis of vascular ED through a systematic PubMed and EMBASE search. According to the different application scenarios, the main methods for the diagnosis of vascular ED are divided into four categories. Intra-cavernous injection of vasoactive drugs is the earliest method used in the diagnosis of vascular ED and is a basic test. For the diagnosis of arterial ED, color duplex Doppler ultrasound, selective penile angiography, magnetic resonance imaging, and computed tomography are more commonly used. While for the diagnosis of venous ED, shear wave elastography, dynamic infusion cavernosometry and cavernosography are more accurate. Endo-peripheral arterial tonometry (PAT) has also been used to detect vascular endothelial function. Although various existing examinations are widely used for the evaluation of vascular ED, they still have some shortcomings, such as invasiveness, contingency, high false positive (negative) rate. New methods of long-term dynamic detection are needed.

Stiffness of the Central Corpus Cavernosum on Shear-Wave Elastography Is Inversely Correlated with the Penile Rigidity Score in Patients with Erectile Dysfunction

Purpose

To perform real-time quantitative measurements of penile rigidity for patients with erectile dysfunction (ED) using shear-wave elastography (SWE).

Materials and Methods

A total of 92 patients with clinically diagnosed ED filled out an abridged five-item version of the International Index of Erectile Function (IIEF-5) questionnaire and underwent SWE as well as penile color Doppler ultrasound (CDUS) after intracavernosal injection for penile erection. Elasticity measurements were repeated on two sites of the corpus cavernosum (central and peripheral elasticity of corpus cavernosum [ECC]) and the glans penis during the erection phase. Correlations between penile elasticity and rigidity scores or IIEF-5 were evaluated statistically. Penile elasticity was also compared with the ED types based on CDUS.

Results

The mean age of all patients was 53.5±13.4 years, and the mean IIEF-5 score was 9.78±5.01. The rigidity score and central ECC value demonstrated a significant correlation (r=−0.272; 95% confidence interval: −0.464 to −0.056; p=0.015). The IIEF-5 score was not significantly correlated with penile elasticity. Vascular ED patients showed significantly higher central ECC values than nonvascular ED patients (p<0.001). At a cut-off value of 8.05 kPa, the central ECC had a specificity of 41.5%, a sensitivity of 84.6%, and an area under the ROC curve of 0.720 with a standard error of 0.059 (p=0.019) for predicting vascular ED.

Conclusions

Quantitatively measuring Young's modulus of the corpus cavernosum using SWE could be an objective technique for assessing penile erectile rigidity and the vascular subtype in patients with ED.

Penile Doppler Ultrasound for Erectile Dysfunction: Technique and Interpretation

OBJECTIVE. Erectile dysfunction (ED) is a common medical condition that has a high prevalence and incidence worldwide and may have a significant impact on both physical and psychosocial health. The purpose of this article is to review the role of penile Doppler sonography in the assessment of ED. CONCLUSION. Penile Doppler sonography is an essential tool for differentiating between vascular and nonvascular causes of ED; therefore, radiologists must be familiar with the imaging protocol, the limitations of the technique, and interpretation of its findings, to warrant an accurate diagnosis and appropriate patient management.