US of the Inguinal Canal: Comprehensive Review of Pathologic Processes with CT and MR Imaging Correlation

Abstract

Ultrasonography (US) has a fundamental role in the initial examination of patients who present with symptoms indicating abnormalities of the inguinal canal (IC), an area known for its complex anatomy. A thorough understanding of the embryologic and imaging characteristics of the contents of the IC is essential for any general radiologist. Moreover, an awareness of the various pathologic conditions that can affect IC structures is crucial to preventing misdiagnoses and ensuring optimal patient care. Early detection of IC abnormalities can reduce the risk of morbidity and mortality and facilitate proper treatment. Abnormalities may be related to increased intra-abdominal pressure, which can result in development of direct inguinal hernias and varicoceles, or to congenital anomalies of the processus vaginalis, which can result in development of indirect hernias and hydroceles. US is also helpful in assessing postoperative complications of hernia repair, such as hematoma, seroma, abscess, and hernia recurrence. In addition, it is often the modality initially used to detect neoplasms arising from or invading the IC. US is an important tool in the examination of patients suspected of having undescended testes or posttraumatic testicular retraction and is essential for the examination of patients suspected of having torsion or infectious inflammatory conditions of the spermatic cord. Online supplemental material is available for this article. RSNA, 2016.

Persistence of the processus vaginalis and its related disorders

“…Premature infants have an increased risk with up to 30% born with an inguinal hernia . Whilst 90% of indirect inguinal hernias in adults are due to a persistent processus vaginalis, in the paediatric population this is almost always the cause …”

“…This carries the risk of incarceration and strangulation . As peritoneal fluid may also enter the patent processus vaginalis, communicating hydroceles frequently co‐exist with congenital inguinal hernias …”

“…34 Whilst 90% of indirect inguinal hernias in adults are due to a persistent processus vaginalis, in the paediatric population this is almost always the cause. 2,5,35,36 Failure of closure of the processus vaginalis at the deep inguinal ring leaves an opening between the peritoneum and the inguinal canal, greatly increasing the likelihood of an indirect inguinal hernia in both paediatric and adult populations. 2 Intra-abdominal contents can enter this opening and, in a completely patent processus vaginalis, may extend to the scrotum or labia majus.…”

“…4,38 As peritoneal fluid may also enter the patent processus vaginalis, communicating hydroceles frequently coexist with congenital inguinal hernias. 36 The role of ultrasound in diagnosis of congenital indirect inguinal hernia Although many inguinal hernias are clinically diagnosed, ultrasound can be used to confirm the diagnosis and to assess clinically equivocal cases. 35 Ultrasound is also used in hernia patients to assess the contralateral inguinal canal for a contralateral patent processus vaginalis.…”

Hernie inguinale étranglée compliquée d’ischémie testiculaire sur perméabilité du canal peritonéo-vaginal

“…Au niveau du canal inguinal, il se ferme complètement et ne laisse qu´un mince cordon fibreux: le ligament de Cloquet. Sa partie distale ne subit aucun changement et forme la vaginale du testicule [ 2 , 3 ]. Chez la fille, le processus vaginal est appelé canal de Nück.…”