Endosonographic imaging of anorectal diseases

Diagnostic approach to faecal incontinence: What test and when to perform?

Faecal incontinence (FI) is a debilitating common end result of several diseases affecting the quality of life and leading to patient disability, morbidity, and increased societal burden. Given the various causes of FI, it is important to assess and identify the underlying pathomechanisms. Several investigatory tools are available including high-resolution anorectal manometry, transrectal ultrasound, magnetic resonance imaging, and electromyography. This review article provides an overview on the causes and pathophysiology of FI and the author’s perspective of the stepwise investigation of patients with FI based on the available literature. Overall, high-resolution anorectal manometry should be the first investigatory tool for FI, followed by either transrectal ultrasound or magnetic resonance imaging for anal internal sphincter and external anal sphincter injury, respectively.

Value of three-dimensional endoanal ultrasound scan (3D-EAUS) in preoperative assessment of fistula-in-ano

Objective

The aim of this study was to determine the accuracy of three-dimensional endoanal ultrasound scan (3D-EAUS) in the pre-operative assessment of fistula-in-ano in identifying the fistula tract and comparing with findings at surgery in a South Asian cohort. A retrospective analysis of 87 patients with suspected fistula-in-ano who underwent pre-operative 3D-EAUS between January 2009 and January 2016 was carried out. All patients subsequently had surgical exploration under anaesthesia (EUA), irrespective of 3D-EAUS findings. The 3D-EAUS results were compared with the surgical findings to determine the accuracy of 3D-EAUS.

Results

A total of 86 (98.9%) patients (male = 75) were subsequently shown to have a fistula at surgical exploration and of them, 3D-EAUS detected a fistula in 79 (92%) patients. In this cohort, 3D-EAUS correctly predicted the surgical findings in (n = 61, 70.9%) patients with the highest accuracy being for transphincteric fistulae (87.1%). However, the overall concordance in our study was low with a kappa coefficient of 0.318. Additional findings such as sphincter defects were detected by the 3D-EAUS in 37 patients (internal sphincter defects-21, external sphincter defects-7, both-9) which were not evident at EUA. Therefore, 3D-EAUS had a good accuracy in selected types of fistulae and particularly useful in identifying sphincter defects before surgery.

Electronic supplementary material

The online version of this article (10.1186/s13104-019-4098-2) contains supplementary material, which is available to authorized users.

Endoanal Ultrasonography of Mucinous Adenocarcinoma Arising from Chronic Fistula-in-ano: Three Case Reports

Mucinous adenocarcinoma arising in chronic fistula-in-ano is rare, and diagnosing it at an early stage is difficult. The role of endoanal ultrasonography in diagnosing the condition has not been discussed in the study. Herein, we report three cases of mucinous adenocarcinoma arising from anal fistulas in which endosonography played an important role in diagnosing malignant change. Three male patients with a 5- to 20-year history of anal fistula were referred to our hospital due to perianal induration, progressive anal pain, or mucopurulent secretion. In all three patients, endosonography revealed a multiloculated complex echoic mass with isoechoic solid components communicating with a trans-sphincteric fistula and sonography-guided biopsy under anesthesia revealed mucinous adenocarcinoma. All patients underwent abdominoperineal resection with lymph node dissection. One patient with a local recurrence died 3 years after surgery and two have remained disease-free for >6 years. These observations suggest that endosonography may be a reliable technique for the diagnosis of mucinous adenocarcinoma arising from chronic fistula-in-ano. Sonography-guided biopsy is useful for the definitive diagnosis of malignancy. Therefore, periodic endosonography assessment should be recommended for patients with persistent anal fistula, especially those with progressive clinical symptoms. Once malignancy is suspected, aggressive sonography-guided biopsy under anesthesia should be performed, which may enable an early diagnosis, curative treatment, and favorable long-term results.

Anal Canal Duplication Associated with Presacral Cyst in an Adult

Anal canal duplication (ACD) is a rare congenital malformation, usually detected early in life. We report a case of a 67-year-old female with symptomatic ACD associated with a presacral cyst. Physical examination revealed an accessory opening located in the midline, posterior to the true anus. Imaging examinations, including fistulography, endoanal ultrasonography, and magnetic resonance imaging, revealed a blind-ending fistulous tract without connecting with the rectum and a presacral cyst posterior to the rectum. Complete surgical excision of the tract with cyst was performed through a posterior sagittal approach. Histologic examination revealed squamous epithelium lining and smooth muscle bundles, thereby confirming ACD. The postoperative course was uneventful, and the patient was doing well; no recurrence was observed 4 years after surgery. ACD can present for the first time in infants, children, and adults. Imaging examinations are useful for the diagnosis and preoperative assessment of ACD. Therefore, ACD should be considered in the differential diagnosis, even in adults, when a posterior perineal orifice is encountered, particularly in female patients. Once ACD is suspected, intense imaging inspection is recommended to visualize the ACD and associated anomalies, and surgical removal is warranted to prevent inflammatory complications or malignant changes.

Systematic Imaging Module in Complete Hindgut Duplication

Complete hind gut and anal canal duplication is a rare entity, usually remaining asymptomatic till the disease comes to light due to associated anomalies or due to cosmetic reasons. Classical imaging consisting of barium enema examination served a limited role, in terms of depicting the length of gut segment involved. Technical advances in magnetic resonance imaging (MRI) with three-dimensional (3D) reformations cannot only solve the above purpose but further evaluate key points needed for surgical planning. The present technical report lays out a systematic module for evaluation of various aspects of complete hindgut duplication, critical for management. The role of 3D MRI is emphasized upon, for evaluation of pelvic floor and anorectum, even in infants with a distorted anatomy.

Peroxide-enhanced 3-dimensional endovaginal ultrasound imaging for diagnosis of rectovaginal fistula

We present a case of a rectovaginal fistula identified with peroxide-enhanced 3-dimensional endovaginal ultrasonography.

CASE

A 36-year-old woman with history of ulcerative colitis, status post-ileoanal J-pouch anastomosis, and total proctocolectomy presented with leakage of stool from her vagina. The fistula tract could not be fully visualized directly or identified on endoanal ultrasonography, but was diagnosed by peroxide-enhanced endovaginal ultrasound.The use of peroxide-enhancement while performing 3-dimensional endovaginal sonographic imaging may be of benefit to patients with rectovaginal fistulas that cannot be fully evaluated by physical examination or more typical use of endoanal ultrasonography.

Transrectal ultrasonography of anorectal diseases: advantages and disadvantages

Transrectal ultrasonography (TRUS) has been widely accepted as a popular imaging modality for evaluating the lower rectum, anal sphincters, and pelvic floor in patients with various anorectal diseases. It provides excellent visualization of the layers of the rectal wall and of the anatomy of the anal canal. TRUS is an accurate tool for the staging of primary rectal cancer, especially for early stages. Although magnetic resonance imaging is a modality complementary to TRUS with advantages for evaluating the mesorectum, external sphincter, and deep pelvic inflammation, three-dimensional ultrasonography improves the detection and characterization of perianal fistulas and therefore plays a crucial role in optimal treatment planning. The operator should be familiar with the anatomy of the rectum and pelvic structures relevant to the preoperative evaluation of rectal cancer and other anal canal diseases, and should have technical proficiency in the use of TRUS combined with an awareness of its limitations compared to magnetic resonance imaging.

Proactive medicine: the "UCI 30," an ultrasound-based clinical initiative from the University of California, Irvine

This article discusses the benefits of integrating point-of-care diagnostic ultrasound into the four-year medical school curriculum. Handheld ultrasound devices have been used to teach medical students at the University of California (UC), Irvine, since August 2010, and the article explains how the use of this inexpensive, safe, and noninvasive tool enhances the ability of a physician conducting a standard physical exam to confirm suspected findings and uncover other suspected pathology at a reasonable cost. The authors describe the ultrasound curriculum at UC Irvine and the process of its implementation. In the appendix to the article, the authors describe the specific diagnostic benefits of using a handheld ultrasound device for each element of the Stanford 25 physical exam. Their ultrasound-enhanced approach to the physical exam is referred to as the "UCI 30." They make recommendations for how and when to integrate ultrasound into the physical exam. The article points out that early training of medical students in the use of ultrasound can avoid the diagnostic problems of ultrasound by maximizing students' comfort and ability to obtain accurate ultrasound images for diagnostic and procedural purposes.

Three-dimensional endoanal ultrasound and anorectal manometry in children with anorectal malformations: new discoveries

BACKGROUND/PURPOSE

Fecal incontinence and constipation are common problems in follow-up of anorectal malformations (ARMs). We evaluated the anal sphincters using the 3-dimensional endoanal ultrasonography (3D-EAUS) and the anorectal manometry after ARMs repair.

METHODS

Seventeen patients, divided into 3 groups according to Wingspread classification, underwent anorectal manometry and 3D-EAUS. Clinical, manometric, and endosonographic scoring systems were used.

RESULTS

The average anal resting pressure (aARP) was significantly higher in low ARMs than in intermediate and high ARMs. The anal squeeze pressure was not statistically different between the 3 groups. Three-dimensional EAUS visualized internal anal sphincter (IAS) disruptions in 7 of 17 patients and absence of IAS in 6 of 17 children with high ARMs. Scars of the external anal sphincter were localized in low ARMs and generalized in the other groups. In the case of IAS disruption with aARP greater than 20 mm Hg, fecal incontinence and constipation improved with biofeedback and/or laxatives, whereas daily enemas were necessary in absence of IAS with aARP less than 20 mm Hg. Statistical correlation was observed between endosonographic and manometric findings and clinical outcomes.

CONCLUSIONS

Lesions of the anal sphincter are common in ARMs. Three-dimensional EAUS and anorectal manometry ensure a complete assessment of the anal sphincter and could provide useful information to define the most appropriate treatments to improve the quality of life.

Three-dimensional anal endosonography in depicting anal-canal anatomy

PURPOSE

This report describes the advantages of 3D anal endosonography in depicting the normal anatomy of the anal canal in relation to sex and age.

MATERIALS AND METHODS

A retrospective study was performed of 85 patients, 33 men and 52 women, previously examined with 3D anal ultrasound (US) for clinically suspected anorectal disease but found to be negative. The examinations were performed with a Bruel and Kjaer US system with a 2050 transducer, scanning from the anorectal junction to the subcutaneous portion of the external anal sphincter (EAS). The 3D reconstructions provided an estimation of sphincter length in the anterior and posterior planes, and axial 2D images enabled calculation of the thickness of the internal anal sphincter (IAS) and EAS in the anterior, posterior and lateral transverse planes.

RESULTS

Distribution of the sphincter complex is asymmetric in both sexes: the EAS and IAS are significantly shorter in females, especially in the anterior longitudinal plane (p=0.005 and p<0.001, respectively). EAS and IAS thickness increases with age, especially the lateral IAS (R(2)=0.37, p<0.001) and the posterior EAS (R(2)=0.29, p=0.01).

CONCLUSIONS

A good knowledge of anal-canal anatomy is essential to detect sphincter abnormalities when assessing pelvic floor dysfunction.

Application of endoscopic sonography in preoperative staging of rectal cancer: six-year experience

OBJECTIVES

The aim of this study was to evaluate our experience with the application of endoscopic sonography in preoperative staging of rectal cancer.

METHODS

Between April 2004 and May 2010, 192 patients with rectal cancer first underwent endoscopic sonography and then underwent surgery at our hospital. None of the patients in this study received neoadjuvant therapy. The endoscopic sonographic staging results were compared with those of postoperative pathologic staging.

RESULTS

The accuracy of overall T staging was 86.5%, and for T1, T2, T3, and T4, the accuracy rates were 86.7%, 94.0%, 86.2%, and 65.5%, respectively. The accuracy of T staging for ulcerated lesions was significantly lower than that for nonulcerated lesions (P = .013). The accuracy of T staging between nontraversable stenotic lesions and traversable lesions was also significantly different (P = .002). The accuracy of N staging was 77.8%, and the specificity and sensitivity were 85.6% and 74.2%, respectively.

CONCLUSIONS

Endoscopic sonography is safe and effective for preoperative staging of rectal cancer and should be a routine examination before surgery. As for ulcerated and nontraversable stenotic lesions, however, the results of endoscopic sonographic staging could be doubtful. Moreover, the accuracy of endoscopic sonographic N staging still needs modification by further research.

Staging anal cancer: prospective comparison of transanal endoscopic ultrasound and magnetic resonance imaging

PURPOSE

The staging of anal cancer is extremely important for therapy and prognosis. Transanal endoscopic ultrasound and magnetic resonance imaging are routinely applied. The aim of this prospective comparative study is to evaluate whether tumor staging is concordant between these techniques.

METHODS

Forty-five anal cancer patients underwent endoscopic ultrasound and magnetic resonance imaging. Histological confirmation was obtained in all patients. The two test methods were compared with the kappa concordance index and sensitivity for the initial method of tumor detection was calculated. For six patients who were operated upon because of tumor progression, the results were evaluated against the histological tumor stage.

RESULTS

High concordance was found in the assessment of tumor size and nodal status (kappa index 0.63 and 0.77). Cancer patients were correctly identified with 100% sensitivity (45/45) by endoscopic ultrasound and with 88.9% (40/45) sensitivity by magnetic resonance imaging. In the six operated patients, T stage was correctly assessed in four of six patients by endoscopic ultrasound and in three of six patients by magnetic resonance imaging.

CONCLUSION

The results of endoscopic ultrasound strongly coincide with those of magnetic resonance imaging. Endoscopic ultrasound may be superior to magnetic resonance imaging for detection of small superficial tumors. However, magnetic resonance imaging is needed for N staging.

Comparison of anorectal manometry to endoanal ultrasound in the evaluation of fecal incontinence

BACKGROUND

Fecal incontinence (FI) is a common clinical condition with a negative impact on the quality of life. Commonly performed tests to evaluate FI include anorectal manometry (ARM) and endoanal ultrasonography (EAU). Objective of our study was to compare the results of these 2 tests in a cohort of patients with FI.

METHODS

Retrospective study of 27 patients (20 women) referred to the gastrointestinal motility clinic for FI. EAU and ARM were performed in all patients. Demographic data and information regarding etiology of FI was also recorded.

RESULTS

Mean age of the patients was 56 years (range 26-87 years). Etiology of FI was obstetric trauma in 4, pelvic surgery in 9, pelvic trauma in 3, pelvic radiation in 1, and idiopathic in 8. Based on the ARM data, 14 of 27 had a weak external sphincter squeeze pressure and 3 had impaired rectal sensation, whereas with the EAU there was thinning of the external anal sphincter in 3 and complete disruption in 1, and abnormalities of the internal anal sphincter (IAS) in 7 of 27 with thinning, and defects. Overall, only 2 of 27 had normal findings by combined ARM and EAU.

CONCLUSIONS

Although the yield of finding major sphincter defects was low, only a small percentage of patients had a normal ARM or EAU. When there are degrees of external anal sphincter thinning or partial or complete disruption of the sphincters, a good correlation with ARM is achieved. EAU and ARM are complimentary investigations for the thorough assessment of the anal sphincter apparatus.

The role of three-dimensional endoluminal ultrasound imaging in the evaluation of anorectal diseases: a review

BACKGROUND

The authors conducted a review of the available English literature to evaluate the advantages of three-dimensional ultrasound for assessing anorectal pathology, to provide a state-of-the-art approach, and to compare this technique with conventional endoluminal ultrasound and other imaging methods.

METHODS

All studies describing results obtained with three-dimensional ultrasound in the evaluation of anorectal pathologies, both alone and compared with other techniques, were selected.

RESULTS

Since 1996, 32 articles have been published. In tumor staging, specific data derived by three-dimensional reconstruction for the assessment of T invasion and nodal involvement were more accurate than endoluminal ultrasound and computed tomography. For evaluating perianal sepsis, the detection of secondary fistula tracts and fluid collections and the location of internal openings were superior to endoanal magnetic resonance imaging. In the evaluation of anal incontinence, the results for sphincter defects were similar to those obtained with endoanal magnetic resonance imaging.

CONCLUSION

Analysis of the literature confirmed that three-dimensional ultrasound is a valuable technique for assessing anorectal disorders, facilitating the interpretation of the images obtained, and providing additional data that in many cases have changed the operative approach.