Imaging has a central role in diagnosing male infertility, according to a review published in RadioGraphics. Scrotal ultrasound and MRI have emerged as the preferred modalities while invasive procedures such as vasography have fallen out of practice, but CT has its uses as well.

Male infertility contributes to 50 percent of couples’ inability to conceive, whether its congenital abnormalities obstructing sperm transport or a problem in sperm production. Imaging can determine to which branch of fertility disorders the patient belongs, with big implications.

Obstructive azoospermia is often correctable through surgery, while un-obstructive azoospermia will require assisted reproduction techniques such as intracytoplasmic sperm injection.

Imaging workups for possible male infertility should not start until after a full year of unsuccessfully trying to achieve pregnancy, according to the article. Imaging is just one aspect of the process which also includes medical history, physical examination and a semen analysis.

“Imaging can also be used to guide methods for impregnating the female partner, such as sperm aspiration from the epididymis or seminiferous tubules followed by in vitro fertilization or intracytoplasmic sperm injection,” wrote lead author Pardeep Mittal, MD, associate professor of radiology and imaging sciences at Emory University School of Medicine.

Scrotal ultrasound is the preferred modality because it is noninvasive, inexpensive, and allows radiologists to examine the reproductive system with multiplanar imaging. The most common correctable cause of male infertility—the enlargement of a testicular vein, called Varicocele—can be easily identified on ultrasound. While it’s present in 15 percent of all men, most still test normally in hormone and semen analysis.

But for those who “abnormal semen parameters” or proven infertility, surgical ligation or embolization of the vessels can provide boosts to sperm concentration, motility, and total sperm count.

Ultrasound is also used to differentiate between vascular and non-vascular causes of erectile dysfunction,  

Testicular volume measurements should also be obtained on ultrasound—they can inform care providers about deficiencies in semen production. While transrectal ultrasound can be used to image the prostate or reproductive tract, barriers to entry limit its usefulness, according to the authors.  

“Operator dependency and the inability to evaluate small-caliber structures are known limitations of transrectal US that make MR imaging the superior noninvasive modality for evaluating the intrapelvic structures,” wrote Mittal et al.

MRI can highlight the fine anatomy of the reproductive tract, making it useful for both diagnostic and interventional purposes. 3D MRI is even better, allowing much thinner image slices and the ability to reformat images to any plane.

MRI is the modality of choice for identifying cysts in a variety of reproductive tract locations, including the ejaculatory ducts or the Cowper glands. CT is less useful for soft-tissue imaging but is well suited for identifying calcifications and stones along the reproductive tract, according to the article.

The first time future parents see their child on a fetal ultrasound is a life-defining moment, cementing imaging’s place in modern reproductive care. While not many men will be posting pictures of an obstructed seminal vesicle on Facebook, imaging to diagnose male infertility still holds an important place on the path to a new life.