Differentiation of Anal Sphincters With High-Resolution Magnetic Resonance Imaging Using Contrast-Enhanced Fast Low-Angle Shot 3-Dimensional Sequences

[Perianal inflammatory diseases : Classification and imaging]

During the past 30 years, classifications and scoring systems have been developed in order to evaluate and objectify the degree and activity of anorectal fistulas. Only a few of these disease-specific instruments have been adopted into daily clinical routine. Generally, clinicians tend to use global medical judgement rather than numeric activity indices, which often seem complex and time consuming. Activity scores in Crohn disease, however, appeared to be very useful in clinical trials regarding evaluation of therapy response. Thus, activity indices must be simple and reproducible. The years 1976 and 1995, in which the Parks Classification and Perianal Disease Activity Index (PDAI) were established, can be considered milestone years for classifying patients with anorectal fistulizing disease. These instruments should be recognized at present as the gold standard for evaluating the complexity as well as the severity of anorectal fistulas and perianal Crohn disease.

Magnetic resonance imaging of perianal fistulas

Perianal fistulization is the result of a chronic inflammation of the perianal tissues. A wide spectrum of clinical manifestations, ranging from simple to complex fistulas, can be seen, the latter especially in patients with Crohn disease. Failure to detect secondary tracks and hidden abscesses may lead to therapeutic failure, such as insufficient response to medical treatment and relapse after surgery. Currently, magnetic resonance (MR) imaging is the preferred technique for evaluating perianal fistulas and associated complications. Initially used most often in the preoperative setting, MR imaging now also plays an important role in evaluating the response to medical therapy.

Hemorrhoids and fistulas: new solutions to old problems

Symptoms thought related to hemorrhoids must be carefully considered before intervention. The first line of therapy for any hemorrhoidal complaint remains conservative management with increased fluid and fiber intake and appropriate modification of toileting behavior. Bleeding in grades 1 and 2 hemorrhoids that does not respond to this can be satisfactorily and safely managed with office-based therapies; some grade 3 hemorrhoids would also respond to this, though more treatment sessions would likely be required. Operative therapy is the best choice for management of persistently symptomatic grade 2 disease and for grades 3 and 4 symptomatic hemorrhoids as well. With proper patient selection and preparation, along with a familiarity with instrumentation and techniques, good results can be obtained with newer operative interventions for internal hemorrhoids. Outcomes must always be compared with those obtained with classic excisional hemorrhoidectomy.

MR imaging of the bowel: pediatric applications

Magnetic resonance enterography with oral contrast administration using fast T2-weighted and fat saturated, contrast-enhanced T1-weighted sequences is the most common technique for bowel evaluation. The main indication for bowel MR imaging in children has been evaluation of inflammatory bowel diseases. A less common application is appendicitis. Other potential applications include evaluation of vascular malformations and transplanted bowel.

Radiologic evaluation of pelvic floor disorders

Several imaging modalities are available ranging from fluoroscopic techniques to ultrasonography and MRI for the evaluation of patients with pelvic floors disorders. High-resolution ultrasonography and MRI not only provide superior delineation of the pelvic floor anatomy but also reveal pathology and functional changes. This article focuses on standard imaging procedures including defecography, ultrasonography, and MRI and discusses its use in clinical practice by illustrating both normal and abnormal patterns.

[Preoperative staging of rectal cancer]

Accurate preoperative staging of rectal cancer is crucial for therapeutic decision making, as local tumor extent, nodal status, and patterns of metastatic spread are directly associated with different treatment strategies. Recently, treatment approaches have been widely standardized according to large studies and consensus guidelines. Introduced by Heald, total mesorectal excision (TME) is widely accepted as the surgical procedure of choice to remove the rectum together with its enveloping tissues and the mesorectal fascia. Neoadjuvant radiochemotherapy also plays a key role in the treatment of locally advanced stages, while the use of new drugs will lead to a further improvement in oncological outcome. Visualization of the circumferential resection margin is the hallmark of any preoperative imaging and a prerequisite for high-quality TME surgery. The aim of this article is to present an overview on current cross-sectional imaging with emphasis on magnetic resonance imaging. Future perspectives in rectal cancer imaging are addressed.

Magnetic resonance imaging of the ischiorectal fossa: spectrum of disease

OBJECTIVE

Pelvic magnetic resonance imaging (MRI) studies are widely used to assess the rectum, anal canal, and their environment. The purpose of this article is to review the current role of MRI in the evaluation of diseases involving the ischiorectal fossa and their imaging features.

CONCLUSIONS

The radiologist plays an essential role in the evaluation of some conditions typically located in this space and of other conditions that occasionally involve this area or invade the ischioanal space. The accurate assessment of these diseases that MRI provides further cements its role as the primary technique for the evaluation of pelvic pathology.

Magnetic resonance imaging measurement of the anorectal striated muscle complex in normal children

PURPOSE

The aim of the study was to describe and establish a normal measurement of the striated muscle complex (SMC) in healthy children using body phased-array or head coil magnetic resonance imaging.

METHODS

Imaging was performed in 20 boys and 20 girls (age range, from 3 months to 14 years; average age, 3.2 years) without anorectal disorders. The dimensions of the puborectalis muscle (PR) and external anal sphincter (EAS) were measured in different planes.

RESULTS

There was a close positive correlation between absolute width and length of SMC and age (P < .05), whereas there was no correlation between the relative width and length of SMC and age (P > .05). Normal relative length of the PR and EAS were measured as 0.47 +/- 0.04 and 0.41 +/- 0.04, respectively, and the normal relative width of PR and posterior EAS were 0.50 +/- 0.04 and 0.44 +/- 0.04 in children younger than 14 years.

CONCLUSIONS

The width and length of PR and EAS increase progressively with age. The relative width and length of PR and EAS were not variable with age. A relative width and length of PR and EAS were chosen as objective criteria for normal SMC in children younger than 14 years.