Cryptorchidism Imaging
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Cryptorchidism is defined as failure of the testis to descend from its intra-abdominal location into the scrotum. The exact etiology of cryptorchidism is not known. In one third of patients, the condition is bilateral. Ultrasonography (US), computed tomography (CT) scanning, magnetic resonance imaging (MRI), arteriography, and laparoscopy are used for diagnosis. [1]
Orchiopexy is the treatment of choice and usually is performed in patients aged 2-10 years. A cryptorchid testis, shown in the image below, is 20-48 times more likely to undergo malignant degeneration than a normal testis. Orchiopexy does not alter the risk of malignant transformation. The incidence of malignant transformation also is increased in the unaffected testis. Consider hormone treatment with either human chorionic gonadotropin or gonadotropin-releasing hormone analogues for palpable high-scrotal position of the testis; however, efficacy is less than 20%. Surgical treatment is most effective and reliable.
No radiologic intervention exists. [2, 3] Ultrasonography is the first imaging modality performed on a cryptorchid testis. Of cryptorchid testes, 72% are in the inguinal canal; therefore, they are easily accessible to US examination. In addition, US is readily available and is easy to schedule. [4] If US cannot identify the testis (US effectively detects cryptorchid testis below the level of the internal inguinal ring), MRI and CT scanning are the subsequent modalities of choice. Both can detect an abdominal testis. [5, 6] Laparoscopy is performed if MRI and CT cannot localize the testis, [7] but it is invasive and expensive.
US cannot detect an intra-abdominal testis, and CT scanning uses radiation and does not have multiplanar capability. MRI has better soft-tissue contrast and multiplanar capability; however, when the testis is higher in the abdomen, the presence of bowel loops lowers the sensitivity for detecting the cryptorchid testis.
Cryptorchid testis is seen as an oval soft-tissue mass along the expected course of testicular descent. Uniform enhancement is seen with intravenous (IV) radiographic contrast. CT is almost as accurate as US in detecting an undescended testis in the inguinal region. CT and MRI are much better than US in detecting an undescended testis that is located abdominally. In one study evaluating undescended testis, CT scan and ultrasonographic accuracy were 96% and 91%, respectively. A lymph node can be differentiated readily by the presence of fatty hilum and its characteristic location.
Perform MRI from the level of the kidneys to the level of the pelvic outlet. The pulse sequences used are T1, T2, and postgadolinium T1-weighted images in the axial and coronal planes. An oval mass that appears as low signal on T1-weighted images and high signal on T2-weighted images is characteristic of an undescended testis. Identification of the mediastinum testis is helpful. [8] MRI detects the malignant degeneration in cryptorchid testis well. [9]
Gadolinium-based contrast agents have been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or MRA scans. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness.
Occasionally, bowel loops and lymph nodes can mimic the undescended testis. CT scanning is much better at differentiating the undescended testis from the bowel loop.
Occasionally, bowel loops and lymph nodes can mimic the undescended testis. CT scanning is much better at differentiating the undescended testis from the bowel loop.
Ultrasonography is the most frequently used imaging study for the testicle. On US, prepubertal testes are of low- to medium-level echogenicity.
A normal adult testis has medium-level echoes and measures 5 X 3 X 2 cm. The tunica albuginea is the fibrous covering of the testicle. Septa extend from the tunica albuginea into the testicle, dividing the testes into lobules. The posterior surface of the tunica albuginea is reflected into the interior of the gland, forming the incomplete septum termed the mediastinum of the testis. Sonographically, this is seen as an echogenic band running across the testis. [10, 11, 12]
The most common location of cryptorchid testis is the inguinal canal (72%), followed by prescrotal (20%) and abdominal (8%) locations. The presence of an oval mass in the inguinal canal (relatively hypoechoic in echo texture with echogenic mediastinum) is diagnostic. (See the image below.) [13]
Rarely, an undescended testis can be confused with an inguinal hernia; real time peristalsis confirms the presence of bowel.
Persistence of pars infravaginalis gubernaculi has been mistaken for the testis. The presence of an echogenic band (mediastinum testis) identifies the maldescended testis.
Testicular venography has fallen out of favor because of the availability of noninvasive tests. The following findings are diagnostic:
Demonstrated presence of the pampiniform plexus
Visualization of testicular parenchyma
A blind-ending testicular vein (usually indicates absent testis)
Angiography is accurate but invasive; thus, it is not preferred. Gadolinium infusion MR venography is an alternative, noninvasive method of evaluating the undescended testis, especially the vanishing testis. It is superior to MRI alone.
Niedzielski JK, Oszukowska E, Słowikowska-Hilczer J. Undescended testis – current trends and guidelines: a review of the literature. Arch Med Sci. 2016 Jun 1. 12 (3):667-77. [Medline].
Martin JM, Gorayski P, Zwahlen D, Fay M, Keller J, Millar J. Is Radiotherapy A Good Adjuvant Strategy for Men with A History of Cryptorchism and Stage I Seminoma?. Int J Radiat Oncol Biol Phys. 2009 Apr 11. [Medline].
Trsinar B, Muravec UR. Fertility potential after unilateral and bilateral orchidopexy for cryptorchidism. World J Urol. 2009 Apr 8. [Medline].
D’Andrea A, Coppolino F, Cesarano E, Russo A, Cappabianca S, Genovese EA, et al. US in the assessment of acute scrotum. Crit Ultrasound J. 2013 Jul 15. 5 Suppl 1:S8. [Medline]. [Full Text].
Wolverson MK, Houttuin E, Heiberg E. Comparison of computed tomography with high-resolution real-time ultrasound in the localization of the impalpable undescended testis. Radiology. 1983 Jan. 146(1):133-6. [Medline].
Krishnaswami S, Fonnesbeck C, Penson D, McPheeters ML. Magnetic resonance imaging for locating nonpalpable undescended testicles: a meta-analysis. Pediatrics. 2013 Jun. 131(6):e1908-16. [Medline].
Stothers L, Shadgan B, Macnab A. Urological applications of near infrared spectroscopy. Can J Urol. 2008 Dec. 15(6):4399-409. [Medline].
Fritzsche PJ, Hricak H, Kogan BA. Undescended testis: value of MR imaging. Radiology. 1987 Jul. 164(1):169-73. [Medline].
Emad-Eldin S, Abo-Elnagaa N, Hanna SA, Abdel-Satar AH. The diagnostic utility of combined diffusion-weighted imaging and conventional magnetic resonance imaging for detection and localization of non palpable undescended testes. J Med Imaging Radiat Oncol. 2016 Jun. 60 (3):344-51. [Medline].
Bree RL, Hoang DT. Scrotal ultrasound. Radiol Clin North Am. 1996 Nov. 34(6):1183-205. [Medline].
Dogra VS, Gottlieb RH, Oka M. Sonography of the scrotum. Radiology. 2003 Apr. 227(1):18-36.
Krone KD, Carroll BA. Scrotal ultrasound. Radiol Clin North Am. 1985 Mar. 23(1):121-39. [Medline].
Dogra VS, Bhatt S, Rubens DJ. Sonographic evaluation of testicular torsion. Ultrasound Clin. 2006. 1:55-66.
Vikram S Dogra, MD Professor of Diagnostic Radiology, Urology, and Biomedical Engineering, University of Rochester School of Medicine; Director, Division of Ultrasound, Associate Chair of Education and Research, Department of Imaging Sciences, University of Rochester Medical Center
Vikram S Dogra, MD is a member of the following medical societies: American College of Radiology, Association of Program Directors in Radiology, Society of Radiologists in Ultrasound, American Institute of Ultrasound in Medicine, American Roentgen Ray Society, Radiological Society of North America, Society of Abdominal Radiology
Disclosure: Nothing to disclose.
Bernard D Coombs, MB, ChB, PhD Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand
Disclosure: Nothing to disclose.
Matthew D Rifkin, MD
Disclosure: Nothing to disclose.
Eugene C Lin, MD Attending Radiologist, Teaching Coordinator for Cardiac Imaging, Radiology Residency Program, Virginia Mason Medical Center; Clinical Assistant Professor of Radiology, University of Washington School of Medicine
Eugene C Lin, MD is a member of the following medical societies: American College of Nuclear Medicine, American College of Radiology, Radiological Society of North America, Society of Nuclear Medicine and Molecular Imaging
Disclosure: Nothing to disclose.
John L Haddad, MD Clinical Associate Professor, Department of Radiology, Weill Medical College of Cornell University; Director of Body MRI, Department of Radiology, Methodist Hospital in Houston
John L Haddad, MD is a member of the following medical societies: American College of Radiology, American Medical Association, and Radiological Society of North America
Disclosure: Nothing to disclose.
Hamid Mojibian, MD Department of Radiology, Mercy Medical Center
Disclosure: Nothing to disclose.
Cryptorchidism Imaging
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