Anatomic variations of cavernous arteries and their effect on measurement of hemodynamic parameters: a power Doppler study

Efficient use of penile Doppler ultrasound for investigating men with erectile dysfunction

BACKGROUND

Vasculogenic erectile dysfunction is the most common type of erectile dysfunction, and penile Doppler ultrasound (PDUS) is a useful tool to assess erectile hemodynamics in the clinician's effort to discuss prognosis and management strategies with the patient.

AIM

We herein describe the PDUS protocol used at our center, including indications, technique, and data interpretation.

METHODS

We describe our institutional experience with PDUS and discuss it in the context of a contemporary review of the literature for this investigation.

OUTCOME

Our institutional PDUS protocol.

RESULTS

To perform PDUS properly, adequate training, equipment, setting, technique, and interpretation are critical. The accuracy of PDUS is entirely predicated on achieving complete cavernosal smooth muscle relaxation. A redosing protocol optimizes the reliability and reproducibility of the hemodynamic data acquired during PDUS. A rigidity-based assessment is performed, and patients are scanned according to the erection rigidity achieved (full hardness) or by administration of maximum dose of the vasoactive agent. Peak systolic velocity is considered a measure of arterial inflow (normal, >30 cm/s), while end diastolic velocity evaluates the veno-occlusive mechanism (normal, <5 cm/s). After the procedure, the patient is evaluated to confirm detumescence. If the patient has a persistent penetration rigidity erection, intracavernosal phenylephrine is administered; however, if detumescence is not achieved with intracavernosal phenylephrine injections alone, corporal aspiration is potentially performed.

CONCLUSION

PDUS is a valuable minimally invasive tool for erectile hemodynamics assessment and an accurate assessment of such, provided that complete cavernosal smooth muscle relaxation is achieved.

Utility of dynamic MRA in the evaluation of male erectile dysfunction

PURPOSE

To assess the efficacy of time-resolved MR angiography (MRA) in evaluating penile vasculature in patients with clinically suspected vascular anomalies contributing to their erectile dysfunction correlating with penile doppler ultrasound (PDUS) findings and clinical outcomes after surgical intervention.

METHODS

Men (n = 26) with signs of early vascular shunting on PDUS underwent time-resolved, contrast-enhanced (0.1 mMol/kg gadobutrol at 1 ml/s followed by saline flush) 3-dimensional spoiled gradient echo T1-weighted MRA sequence performed over 3 min with 4.6 s frame rate after intracavernosal injection of an erectogenic agent. Additional T1- and T2-weighted sequences were performed for anatomic co-localization and tissue characterization. MRA images were evaluated for early filling of draining veins as well as arteriovenous malformations and fistulas and correlated with findings at surgery.

RESULTS

29 MRA examinations on 26 patients (mean age 39 years) demonstrated abnormal early venous drainage (n = 22) as well as diminutive/delayed cavernosal enhancement (n = 3), incomplete tumescence (n = 2), and combined arterial inflow/venous outflow disease (n = 1). The MRA had a concordance of 85.2% at determining the presence, or lack thereof of a shunt/AVM when compared to PDUS.

CONCLUSIONS

Time-resolved MRA allows for both temporal and spatial resolution with visualization of both arterial and venous abnormalities which may be suggested with a screening PDUS examination. This technique allows us to provide detailed anatomic information prior to any surgical intervention.

The engineering analysis of bioheat equation and penile hemodynamic relationships in the diagnosis of erectile dysfunction: part I-theoretical study and mathematical modeling

The extent to which skin surface bioheat perfusion predicts penile physiological response such as an erection has not been extensively investigated. A biomechanical engineering study was performed to compare bioheat distribution on penile skin surface resulting from an induced erection at steady state to examine the efficacy of such method as an adjunct tool for the diagnosis and classification of erectile dysfunction (ED) due to different etiology. We based our arguments on the principle that blood vessel activity and perfusion to corpus cavernosa at the erect state are almost always higher than that in the flaccid state. Our results showed that a difference of 0.1-0.3 degrees C can be observed and hence used to develop database of 'smart diagnosis' for ED using the machine artificial intelligence. It is anticipated that such basic research into blood flow is critical, as blood perfusion into corpus cavernosa is the most influential factor determining functional erectile quality contributing to successful coitus. Increased understanding of the hemodynamic response profile contributes toward optimal treatment and thus enables clinicians to adopt an appropriate management scheme for ED.

ORIGINAL RESEARCH—PHYSIOLOGY: Thermography as a Physiological Measure of Sexual Arousal in Both Men and Women

INTRODUCTION

Current physiological measures of sexual arousal are intrusive, hard to compare between genders, and quantitatively problematic.

AIM

To investigate thermal imaging technology as a means of solving these problems.

METHODS

Twenty-eight healthy men and 30 healthy women viewed a neutral film clip, after which they were randomly assigned to view one of three other video conditions: (i) neutral (N = 19); (ii) humor (N = 19); and (iii) sexually explicit (N = 20).

MAIN OUTCOME MEASURES

Genital and thigh temperatures were continuously recorded using a TSA ImagIR camera. Subjective measures of sexual arousal, humor, and relaxation were assessed using Likert-style questions prior to showing the baseline video and following each film.

RESULTS

Statistical (Tukey HSD) post-hoc comparisons (P < 0.05) demonstrated that both men and women viewing the sexually arousing video had significantly greater genital temperature (mean = 33.89 degrees C, SD = 1.00) than those in the humor (mean = 32.09 degrees C, SD = 0.93) or neutral (mean = 32.13 degrees C, SD = 1.24) conditions. Men and women in the erotic condition did not differ from each other in time to peak genital temperature (men mean = 664.6 seconds, SD = 164.99; women mean = 743 seconds, SD = 137.87). Furthermore, genital temperature was significantly and highly correlated with subjective ratings of sexual arousal (range r = 0.51-0.68, P < 0.001). There were no significant differences in thigh temperature between groups.

CONCLUSION

Thermal imaging is a promising technology for the assessment of physiological sexual arousal in both men and women.

Duplex ultrasonography detects clinically significant anomalies of penile arterial vasculature affecting surgical approach to penile straightening

OBJECTIVES

To determine the frequency of aberrant penile arterial anatomy in men with Peyronie's disease (PD) and the potential impact on the surgical approach to penile straightening.

METHODS

A retrospective analysis of 63 consecutive men undergoing penile duplex ultrasonography in preparation for penile straightening surgery was performed. They were compared with a group of 61 men with erectile dysfunction (ED) undergoing penile duplex ultrasonography during the same period.

RESULTS

Arterial anomalies distal to the pubic symphysis were noted in 44% of men with PD and 46% of men with ED. The most common anomaly observed was crossing cavernosal arteries seen in 37% of the men with PD and 39% of the men with ED. Distal perforators of the dorsal artery supplying the cavernosal bodies were observed in 10% and 8% of the men with PD and ED, respectively. No difference was found in the overall frequency or type of arterial anomalies between the two groups.

CONCLUSIONS

Men with PD have a high prevalence of arterial anomalies, including distal perforating arteries. Their preoperative evaluation should include duplex ultrasonography with delineation of the penile arterial anatomy. This will aid in surgical planning and potentially prevent maneuvers that may adversely affect the cavernosal blood supply and place the patient at risk of postoperative ED.