The Role of Imaging in Diagnosing Erectile Dysfunction
Imaging helps rule out underlying conditions that may be causing dysfunction
Note: This story is part of an RSNA Special Focus section on men's health.
The advent of new cutting-edge imaging technologies including CT cavernosography, MR angiography and functional brain studies are advancing the study of erectile dysfunction (ED) and providing important information to both physicians and patients for treatment decision making.
ED, defined as the inability to attain or maintain a penile erection of sufficient quality to permit satisfactory sexual activity, affects an estimated 52% of men in the U.S. between 40 and 70 years of age. As many as 150 million men globally suffer from some form of ED. However, researchers say these estimates are likely grossly underestimated because physicians may be reluctant to ask patients about their sexual health while many other patients are embarrassed and fail to seek medical attention for ED issues.
Diagnostic Imaging Tools for ED
The cause of ED is often multifactorial, including both physiologic and psychological issues. A variety of pathologies, from neurological and endocrine disorders to medication side effects, may contribute to ED. While a thorough medical history and physical exam guide the management of ED, various imaging tests can help distinguish whether the condition has an obvious underlying physiologic cause.
“Over the past few decades, various state-of-the-art imaging modalities have been developed and utilized to provide more objective evaluation for ED to better characterize penile health and exclude psychogenic components,” said Eric Chung, MBBS, associate professor of surgery in the Department of Urology at The University of Queensland in Brisbane, Australia and author of a Medical Sciences study on novel imaging studies for ED evaluation. “Imaging for ED provides critical information for diagnosis and also serves a role in ongoing surveillance of treatment response and prognosis.”
Imaging for Advanced ED
Traditional imaging studies for males with ED include penile Duplex ultrasonography of the cavernous arteries, and in select patients, dynamic infusion cavernosometry and cavernosography. However, recent advances in imaging technology with CT cavernosography or MR angiography can serve as an excellent tool both for surgical planning and educating patients about their condition.
The combination of conventional CT with 3D volume rendering can improve imaging of corporal tissue and venous leakage of penile veins. Additionally, functional brain imaging studies may provide insights into potential neural connectivity and signaling pathways changes underlying some forms of ED and potentially permit novel treatment strategies in the future.
“CT cavernosography is performed at only a handful of institutions worldwide,” according to Mohanned Alnammi, MD, a radiology resident at the Lahey Hospital and Medical Center in Burlington, MA. “This imaging technique requires interdisciplinary effort between urology and radiology to generate a high number of cases.”
Dr. Alnammi presented on the topic of CT cavernosography at the RSNA annual meeting in 2020.
“The 3D images from CT cavernosography provide anatomical detail that allows us to see the exact location and severity of venous leakage and to identify other causes of ED, such as penile corporal fibrosis in advanced Peyronie’s Disease,” Dr. Alnammi said. “When the images show fibrosis in the cavernosa, patients can see there is less functioning penile tissue to fill with blood. This helps inform the patient who may be considering a penile implant and allows for shared decision making. It’s empowering to patients to understand their disease and make informed decisions on their treatment options.”
Dr. Chung said CT cavernosography and MR angiography will play a major role toward the development of super-selective penile artery stenting. In this procedure a wire stent is placed within the branches of the internal pudendal artery to treat blockages that are reducing arterial blood flow to the penis during sexual simulation. Penile artery stenting as a treatment for ED is still in clinical research trials.
Imaging Studies for ED
Penile duplex ultrasound: Provides an anatomic assessment of penile structures and measures arterial vascular flow. Normal end diastolic velocity may also exclude possible veno-occlusive dysfunction and venous leak. It’s also useful following penile trauma, post-priapism and for ED patients who fail to respond to oral agents.
Dynamic infusion cavernosometry and cavernosography (DICC): Invasive test that involves injection of contrast into one of the corpus cavernosum. Allows for assessment of both arterial insufficiency and venous leaks.
MR angiography: Uses specialized MRI sequences to provide high quality images of the arteries to look for vascular anatomical variations or stenosis.
PET/CT: Molecular imaging test which evaluates physiologic uptake of a PET radiotracer (commonly 18F-FDG or 18F-NaF) with CT for anatomic localization. Vascular uptake has been associated with atherosclerotic and cardiovascular risk factors, which in penile vessels may be a source of ED.
Functional MRI (fMRI): Neuroimaging technique which seeks to better understand the neuroanatomical causes of ED.
CT cavernosography: Invasive test involves injection of contrast into one of the corpus cavernosum. Multiplanar and 3-D reformatted CT images allow for examination of penile anatomy and evaluation of venous leaks in patients with advanced ED.
ED May Signal Underlying Health Conditions
Seeking medical help for ED is critical because the condition may be an important marker of elevated cardiovascular risk. Almost 50% of men with known coronary artery disease proven by cardiac catheterization have moderate to severe ED. Researchers believe this correlation is related to underlying endothelial dysfunction and the fact that the smaller penile arteries are more likely to be blocked in patients with significant coronary atherosclerosis.
“Given the proven association between ED and cardiovascular diseases, ED is not about an isolated penis problem, but rather a sign of general health and a risk factor for future vascular events and overall mortality,” Dr. Chung said. “It’s important that the basic workup for men with ED includes screening for cardiovascular risk factors.”
In addition to cardiovascular disease, there are strong correlations between ED and hypertension, diabetes, obesity, smoking, alcoholism, benign prostatic hyperplasia (BPH) and depression.
“Cardiovascular disease and metabolic diseases such as diabetes and hypertension are known causes of ED so it’s important for patients to be referred to specialists for these conditions,” Dr. Alnammi said.
Effective treatments for ED are available and should be tailored to individual needs, including oral and injectable vasoactive medications, external vacuum devices and penile prosthesis surgery.
“In the current ageing population, the incidence of ED will continue to grow,” Dr. Chung concluded. “It’s important that clinicians standardize the diagnostic imaging algorithm and protocols so that treatment will be consistent and evidence-based.”
For More Information
Access the Medical Sciences study at mdpi.com.
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