The Penile Ultrasound: How Advanced Practice Providers Can Perform This Important Diagnostic Test
The penile doppler ultrasound (PDU) is a dynamic, noninvasive imaging modality that allows the depiction of normal penile anatomy and real-time measurement of pathologic changes. PDU can also provide insight into the arterial and venous hemodynamic condition of the penis. Thus, PDU is a valuable tool for evaluating and diagnosing various conditions such as Peyronie's disease (PD), erectile dysfunction (ED), penile trauma, and priapism. Advanced Practice Providers (APPs) are good candidates to perform this diagnostic procedure to establish appropriate medical management for patients.
Beyond sexual function indications, PDU may serve to help identify other medical conditions, such as the early detection of silent coronary artery disease (CAD) in men presenting with ED. Now recognized as one of the earliest manifestations of small vessel disease, ED signals endothelial dysfunction and peripheral vascular disease, making PDU helpful in determining the need for further cardiac assessment. PDU also helps differentiate and detect noncalcified fibrous plaques when choosing treatment options for patients with PD. For many cancer patients, including those undergoing prostate cancer treatment, ED is a common complication that may be further evaluated with PDU to help identify the presence of veno-occlusive dysfunction.
When preparing a patient for a penile ultrasound, providers may wish to remind the patient not to take sildenafil (Viagra) or any other ED medication on the day of the procedure (or the day prior in the case of tadalafil [Cialis]) and recommend wearing loose-fitting pants to the appointment.
Providers performing PDU need a firm understanding of penile anatomy, vasculature, and the physiological erection cycle. When performing the penile ultrasound, the patient should be supine with the penis positioned over the abdomen. The penis is scanned from its ventral surface using longitudinal and transverse views. The ultrasound examination is first carried out while the penis is flaccid, then after administering a corporeal injection of vasoactive drugs to induce an erection. General rules of privacy should be observed.
Before administering the vasoactive agent, the provider should provide the patient with information about possible complications, including priapism, hypotension, hematoma, and pain following the injection. In addition, because the patient may be nervous about injection into the penis, it is helpful to inform the patient that while the injection may be uncomfortable, it is generally not painful.
The injection should be administered at a 90-degree angle to the side of the shaft of the penis, avoiding the top center “midline” of the penis. Viewing the top of the penis as 12 o’clock, the correct injection location is between either 9-11 o’clock or 1-3 o’clock. After administering the injection, the patient should hold the penis firmly at its base for 40-60 seconds so that the medication remains in the corpora cavernosa (CC). The patient should be left alone in the room for 5-10 minutes with erotic stimuli available if desired to achieve maximum benefit.
To perform the ultrasound, the provider will apply ultrasound gel to the penis and obtain vascular measurements of the penis in the erect state. Some providers also elect to obtain measurements in the flaccid state, prior to administration of erectogenic medications, or may repeat measurements periodically throughout the erection. Once the vascular assessments have been performed, the probe is moved over the outside of the penis transversely. If the patient is being evaluated for PD, the provider should give particular attention to the location and size of any fibrous plaques on the penis.
The provider should obtain images of at least one of the two cavernous arteries (CAs), determine the diameters of the CA, and record systolic and end-diastolic blood flow volumes to the penis for all patients. Although the optimal location for assessment of the CAs has not been universally agreed upon, one common location is at the junction of the proximal one-third and the distal two-thirds of the penile shaft.
When the ultrasound is complete and all necessary measurements have been recorded, the patient should remain in the office for at least 30-60 minutes to monitor for a prolonged erection. If the erection remains fully rigid after a period of observation, intracavernosal phenylephrine (100-500 mcg) may be required.
Resources:
Broward Urology Center. (2019). Penile Doppler Ultrasound. http://www.browardurologycenter.com/treatments/advanced-imaging/penile-doppler-ultrasound.
Fernandes, M., de Souza, L., & Cartafina, L.P. (2018). Ultrasound evaluation of the penis. Radiologia Brasileira, 51(4), 257–261. https://doi.org/10.1590/0100-3984.2016.0152.
Gupta, N., Herati, A., & Gilbert, B.R. (2015). Penile doppler ultrasound predicting cardiovascular disease in men with erectile dysfunction. Current Urology Reports, 16(16). doi: 10.1007/s11934-015-0482-1
Hellstrom, W., Raheem, O.A., Drury, R., Dick, B.P., Kim, J., Shalaby, H., & Sikka, S. (2021, March 16). How to Perform a Penile Duplex Doppler Ultrasound [Video]. https://www.vjpu-issm.info/videos/peer-reviewed/5-miscellaneous/item/186-how-to-perform-a-penile-duplex-doppler-ultrasound
Jung, D.C., Park, S.Y., & Lee, J.Y. (2017). Penile doppler ultrasonography revisited. Ultrasonography, 37(1), 16-24. doi: 10.14366/usg.17022
Memorial Sloan Kettering Cancer Center. (2021, February 5). About Your Penile Ultrasound. https://www.mskcc.org/cancer-care/patient-education/about-your-penile-ultrasound
