Letter from the Guest Editor

Article Outline

• Copyright

Recent technical and engineering advances in magnetic resonance imaging (MRI) and ultrasound have allowed diseases of the anus and rectum to be characterized and staged with far greater accuracy than was previously possible. Not only has the resolution of these modalities improved dramatically, but the ability to obtain images and reformat these in multiple planes now provides operating surgeons with useful preoperative information and enables them to plan the most appropriate surgical therapies. Moreover, advances in the surgical management of rectal tumors, including transanal and laparoscopic resections, now allow less invasive procedures to be undertaken and imaging has become crucial in the surgical planning of these patients.

This issue of Seminars in Ultrasound, CT, and MRI focuses on the role of imaging for common diseases of the anus and rectum. Dr. Andrew Bennett describes the correlative imaging of the anus and rectum using both ultrasound and MRI and illustrates the complementary role that these two modalities play in characterizing normal and abnormal anatomic structures. With interventions in the surgical management of patients with pelvic floor disorders that may result in incontinence, imaging of the anal sphincter and related structures is being performed with greater frequency and provides particularly useful information to the ordering physicians. Dr. Jaap Stoker, an authority on imaging in this field, describes the role of MR in evaluating the anal sphincter and disorders associated with the sphincter mechanism. As an extension of this, dynamic MRI of the pelvic floor during voiding is also being used with greater frequency and Dr. Elizabeth Dann describes the emerging role of MR defecography and how this can be utilized to guide management in patients with disorders of defecation, specifically, chronic constipation or fecal incontinence. Dr. Gethin Williams, well versed in the fine art of video defecography, illustrates the common techniques for performing and interpreting these dynamic evaluations of the mechanisms involved with defecation. Dr. Williams' review is a practical user's guide for how to perform a defecogram and how to interpret the study as well as a pictorial guide to the common entities that are likely to be seen.

Imaging has always played an important role in characterizing and staging tumors of the rectum. Dr. Katherine Krajewski describes the role of high-resolution endorectal ultrasound for staging tumors of the rectal wall and illustrates common pitfalls and challenges that may occur when staging these tumors. This article is complemented by an article by Dr. Martin Smith, describing the role of MRI for staging rectal tumors. Dr. Smith illustrates the multiplanar capabilities of MRI and shows how MR of the rectum can be optimized to facilitate surgical planning. Perianal fistula disease has always been a challenge for characterizing the extent of disease and for guiding choice of therapy. Dr. Maryellen Sun illustrates the role of ultrasound, endoanal peroxide fistulography, and MRI to localize, characterize, and document the extent of perianal fistula disease. Dr. Stephan Anderson describes imaging for anorectal trauma and the role that different imaging modalities have for not only characterizing the extent of injury but for guiding clinical management decisions. Dr. Suvranu Ganguli and colleagues illustrate the spectrum of interventional procedures that can be performed via the transanal and transrectal route and share in their technical expertise with what can, at times, be challenging procedures.

Imaging now plays an important role in evaluating the spectrum of disorders associated with the anus and rectum, and this edition of Seminars in Ultrasound, CT, and MRI provides a comprehensive overview of the spectrum of disorders and how the different imaging modalities are used to optimize patient care.