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Extension of perianal inflammation (cryptoglandular hypothesis). If an abscess develops in a superficial gland, the rupture of the abscess extends into the intersphincteric space forming a fistular tract that reaches the skin. Alternatively, a pelvic infection may pass through the external sphincter and enter the ischioanal fossa. The infection sometimes extends to the low perianal space and the supralevator space.
Source publication
Transrectal ultrasonography (TRUS) has been widely accepted as a popular imaging modality for Epub ahead of print 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 t...
Context in source publication
Context 1
... fistulas are caused by various inflammatory diseases including Crohn disease, pelvic infection, diverticulitis, and tuberculosis, as well as by pelvic malignancy, trauma, or radiation therapy [33]. Fistulas are believed to form most commonly secondary to impaired drainage of the anal glands, which is known as the cryptoglandular hypothesis ( Fig. 9) [34]. Perianal fistulas have been divided into inter-, trans-, extra-, and suprasphincteric types by Parks et al. [35]. The treatment of perianal fistulas is primarily surgical and includes a fistulotomy or fistulectomy of the tracts combined with abscess drainage [36]. The major role of imaging modalities in evaluating perianal ...
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In the last decade, the ultrasound has become the tool with the most clinical impact in making decisions for medical specialties and it is considered the stethoscope of the 21 st century. In anorectal diseases, endoanal, endorectal, transperineal (translabial) and endovaginal ultrasounds are used to carry out comprehensive patient assessment. The d...
Chronic anal fissure is a linear ulcer in the anal canal that has not cicatrized for more than 8-12 weeks of treatment. Most anal fissures are idiopathic and are located in the posterior midline. Squamous cell carcinoma of the anus commonly presents as bleeding and anal pain. It may also present as a mass, nonhealing ulcer, itching, discharge, feca...
Citations
... All examinations were performed by a single radiologist (A.A.) using a bK Flex Focus ultrasound scanner 1202 (BK, Herlev, Denmark) with a model 2052 probe equipped with automated multifrequency crystals (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16), with 360° mechanical rotation, fractional band with 96.2% and stainless-steel reflector with field depth up to 8 cm. No patient preparation is required. ...
... It is considered hypertrophied when it measures more than 5 mm in thickness [6]. (E) Neoplastic lesion: hypoechoic mass lesion invading the sphincteric layer [8]. ...
... Only 4 cases included in our study complained of low rectal cancer involving the anal sphincter, with both MRI and 3D EAUS depicted both sphincters were involved with almost perfect agreement. In accordance with our results, Kim [8] stated that the EAUS can accurately determine the depth of penetration of the anal canal cancer into the sphincter complex which it is important as it is closely associated with prognosis of the patients after chemoradiotherapy. Our study concluded that there was an overall almost perfect agreement between EAUS and external phased array MRI in detection of the IAS lesions (Κ w = 0.972) (97.92%) and overall fair agreement in detection of the EAS lesions (Κ w = 0.37) (66.67%), revealed more detectable external sphincter fistulous affection, injuries and exclusively detectable external sphincter atrophy by MRI. ...
Background
The anal sphincteric complex is formed by internal and external sphincters making two partially overlapping tubes around the anal canal. Anal sphincteric lesions represent a spectrum of entities with different patients’ presentations and surgical managements. Endoanal ultrasound has an increasing role in detection and evaluation of anal sphincteric lesions as compared to MRI of the anal canal. The aim of this work was to compare between the 3D EAUA and external phased array MRI in detection and evaluation of anal sphincteric lesions.
Results
There is almost perfect agreement of 97.92% ( Κ w = 0.972) between 3D EAUS and external phased array MRI in the detection of the internal anal sphincter lesions and fair agreement of 66.67% ( Κ w = 0.37) in the detection of the external anal sphincteric lesions.
Conclusions
3D EAUS and external phased array MRI are comparable imaging techniques in the detection of the internal anal sphincter lesions, while the MRI could detect more external sphincteric lesions than EAUS.
... However, in many instances, these two methods are unable to detect highly restricted (suprasphincteric), subcutaneous, horseshoe-type, or small additional branching lesions. 4 MRI offers excellent soft-tissue contrast, facilitating the direct visualization of internal openings, stula tracks, and abscess cavities and their quantity. Although it is the most advanced noninvasive preoperative assessment method for stula-in-ano, MRI has limitations for visualizing the connection between the internal opening and stula track. ...
... In addition, gas formation inside the track resulting from the use of hydrogen peroxide may cause acoustic shadowing, which may be mistaken as a pathological track extension. 4 MRI offers many advantages, including excellent soft-tissue resolution, multiplanar scanning, and direct 3D imaging. Owing to the immobile nature of the pelvic organs, high-quality images can be obtained to display the anatomy of the perianal region accurately. ...
Background
Fistula-in-ano is an abnormal tunnel formation linking the anal canal with the perineum and perianal skin. Multiple imaging methods are available to evaluate it, among which magnetic resonance imaging (MRI) is the most advanced noninvasive preoperative method. However, it is limited in its visualization ability. Therefore, this study aimed to investigate the feasibility of using a specific mixture of 3% hydrogen peroxide (HP) and gadolinium as a direct contrast agent for high-resolution HPMRI of perianal fistula. Additionally, it investigated the value of this new method for preoperative examination of complex or recurrent fistula via a preliminary study.
Methods
Preoperative physical examination, conventional ultrasonography, MRI plain scan, and high-resolution direct HPMRI fistulography data from nine patients with surgically confirmed complex or recurrent fistula-in-ano were retrospectively analyzed. We also assessed the detection rates of fistula tracks and their associated internal openings, including the connection between them and the internal and external anal sphincters. Furthermore, the detection of perianal abscess was analyzed relative to the intraoperative observations.
Results
Surgical confirmation revealed nine cases of anal fistula, including 17 internal openings, 18 fistula tracks, 21 external openings, and six perianal abscesses. ROC curve analysis revealed that the effectiveness of the physical examination, conventional ultrasound, and MRI plain scans for detecting internal openings was lower than that of high-resolution direct HPMRI fistulography (Z = 3.739, 2.642, 2.642, all p < 0.05). The efficacy of physical examination and conventional ultrasound in detecting fistula tracks was lower than that of high-resolution direct HPMRI fistulography (Z = 2.394, 2.503, all p < 0.05). The effectiveness of physical examination in detecting perianal abscess was inferior to that of high-resolution direct HPMRI fistulography (Z = 3.417, p < 0.05). No statistically significant difference was observed in the ability of MRI plain scan to detect fistula tracks or in the capacity of conventional ultrasound to detect perianal abscesses than that of high-resolution direct HPMRI fistulography.
Conclusions
This novel high-resolution direct HPMRI fistulography technique enhances the visualization of recurrent and complex fistula-in-ano, enabling visualization of branched fistulas, thereby improving surgical outcomes.
... Transrectal US has been widely accepted as a promising imaging modality in patients with diverse anorectal disorders, allowing satisfactory evaluation of the lower rectum, anal sphincters, and pelvic floor structures (1). ...
... It is described as "inability to defer the release of gas or stool from the anus and rectum by mechanisms of voluntary control" (20). Common causes include traumatic sphincter defects (e.g., childbirth in women), rectal prolapse, anorectal malformations, complications after surgery for Hirschsprung's disease, and others (1,20,21). Transrectal US is capable of assessing the sphincter integrity in adults and diagnosing sphincter disruption in approximately 95% of cases (Fig. 5) (21). ...
INTRODUCTION: Benign and malignant conditions of the anus, perianal space, and rectum encompass various disorders: perianal abscesses and fistulas, anal fissures, hemorrhoids, incontinence, defecation disorder, rectovaginal and rectovesical fistulas, rectal prolapse, neoplasms of the anal canal and rectum. Very often patients have more than one condition. The high prevalence of benign anal disorders makes them socially significant. In the last two decades, a lot of new diagnostic methods were introduced. This has improved the understanding of the pathogenesis of these conditions. Endoanal and endorectal endoscopic ultrasound has become an important part of the evaluation of anal and rectal disease. This method is widely preferred because of its low price, accessibility, lack of complications, and good tolerance to the examination without sedation. MATERIALS AND METHODS: Thirty patients have undergone endorectal ultrasound (ERUS) examination, from April 2023 to June 2023. All ERUS examinations were performed using 3D 20R3 and 3D X14L4 endorectal transducers connected to BK 3000 Ultrasound System (BK Medical Aps, Denmark). RESULTS: The mean age was 48.4. Eighteen patients were male (60%). The main clinical indication was an evaluation of perianal abscesses and fistulas or neoplasms. Nine of the examinations, or 30%, were performed for anal and rectal tumors. Perianal abscesses were identified in 7 cases (23%); 5 patients had anal fissures; 4 had perianal fistulas (13%); 1 had a rectovaginal fistula. The rest of the patients had hemorrhoidal disease. CONCLUSION: Endorectal and endoanal ultrasound is a sensitive and reliable method for the assessment of the anatomical structures and diagnosis of benign and malignant diseases of the anus, perianal space, and rectum.
... However, in many instances, these two methods are unable to detect highly restricted (suprasphincteric), subcutaneous, horseshoe-type, or small additional branching lesions. 4 MRI offers excellent soft-tissue contrast, facilitating the direct visualization of internal openings, stula tracks, and abscess cavities and their quantity. Although it is the most advanced noninvasive preoperative assessment method for stulain-ano, MRI has limitations for visualizing the connection between the internal opening and stula track. ...
... In addition, gas formation inside the track resulting from the use of hydrogen peroxide may cause acoustic shadowing, which may be mistaken as a pathological track extension. 4 MRI offers many advantages, including excellent soft-tissue resolution, multiplanar scanning, and direct 3D imaging. Owing to the immobile nature of the pelvic organs, high-quality images can be obtained to display the anatomy of the perianal region accurately. ...
Background: Fistula-in-ano is an abnormal tunnel formation linking the anal canal with the perineum and perianal skin. Multiple imagining methods are available to evaluate it, among which magnetic resonance imaging (MRI) is the most advanced noninvasive preoperative method. However, it is limited in its visualization function. Therefore, this study aims to investigate the feasibility of using a specific mixture of 3% hydrogen peroxide (HP) and gadolinium as a direct contrast agent for high-resolution MRI (HPMRI) of perianal fistula. Additionally, it investigated the value of this new method for preoperative examination of complex or recurrent fistula via a preliminary study.
Methods: Preoperative physical examination, conventional ultrasonography, MRI plain scan, and high-resolution direct HPMRI fistulography data from nine patients with surgically confirmed complex or recurrent fistula-in-ano were retrospectively analyzed. We also assessed the detection rates of fistula tracks and their associated internal openings, including the connection between them and the internal and external anal sphincters. Furthermore, the detection of perianal abscess was analyzed relative to the intraoperative observations.
Results: Surgical confirmation revealed nine cases of anal fistula, including 17 internal openings, 18 fistula tracks, 21 external openings, and six perianal abscesses. ROC curve analysis revealed that the effectiveness of the physical examination, conventional ultrasound, and MRI plain scans for detecting internal openings was lower than that of high-resolution direct HPMRI fistulography (Z = 3.739, 2.642, 2.642, all p < 0.05). The efficacy of physical examination and conventional ultrasound in detecting fistula tracks was lower than that of high-resolution direct HPMRI fistulography (Z = 2.394, 2.503, all p < 0.05). The effectiveness of physical examination in detecting perianal abscess was inferior to that of high-resolution direct HPMRI fistulography (Z = 3.417, p < 0.05). No statistically significant difference was observed in the ability of MRI plain scan to detect fistula tracks or in the capacity of conventional ultrasound to detect perianal abscesses than that of high-resolution direct HPMRI fistulography.
Conclusions: This novel high-resolution direct HPMRI fistulography technique enhances the visualization of recurrent and complex fistula-in-ano, enabling visualization of branched fistulas, thereby improving surgical outcomes.
... Endoanal, transrectal, and endovaginal ultrasound are also excellent alternatives for visualization of the anal canal [19,20] and the pouch if they are available. Endoanal and transrectal scan allow direct assessment of the bowel with option of 3D acquisitions and reconstruction [21,22]. ...
... Ultrasound can also be used for the detection of transmural extension, as it provides excellent distinction of the bowel wall layers, the serosa and the mesentery. Evidence of direct mesenteric invasion, and regional lymphadenopathy are well seen with ultrasound, especially if endorectal or endovaginal scans are used [20,36]. ...
This manuscript focuses on a review of the normal and abnormal sonographic appearance of the surgically created pouch as part of an article series on the topic. It includes information regarding sonographic technique, normal anatomy, and commonly encounter diseases and complications.
... Volume reconstruction of axial images can precisely present the anatomy of the anal canal and anal sphincters. Several articles described the use of EAUS in cases of anal sphincter defects, 11 anal fistulas, 12 perianal abscesses, 13 and anal tumors. 14 However, we found only a single study in the literature that studied anal sphincter anatomy in patients with hemorrhoids. ...
Objectives: The literature lacks enough research about the condition of the anal sphincters in patients with hemorrhoids. The aim of this study was to assess the thickness of internal and external anal sphincters (EAS) in patients with hemorrhoids using 3-dimensional endoanal ultrasonography. Materials and Methods: This cross-sectional study non-randomized comparative study included 75 patients with internal hemorrhoids of 3 rd and 4 th degree and 75 healthy individuals as a control group. Endoanal ultrasound examination was done for all participants. The mean thickness of the internal anal sphincter (IAS) and EAS was measured (in mm) at the mid part of the anal canal at rest and during straining (pushing). Results: Concerning IAS, its thickness during rest was apparently higher in the hemorrhoids group compared to the control group (p=0.071), and comparable in the two groups during push (p=0.175), so It did not change significantly with push in the two groups. The hemorrhoids group had significantly thicker EAS compared to the control group during rest and on push (p=0.025, and 0.022, respectively). Pushing resulted in a significant increase in the thickness of EAS in the control group (p=0.004), but not in the hemorrhoids group (p=0.132). Conclusion: In hemorrhoidal disease, IAS and EAS are thickened during rest, but the EAS doesn't increase in thickness as occurring in control group in face of increased tension inside the anal canal during pushing. This may suggest a new pathophysiology for hemorrhoids as being a mechanism which developed to increase the thickness of the wall to protect anal canal wall from increased tension during push.
... Volume reconstruction of axial images can precisely present the anatomy of the anal canal and anal sphincters. Several articles described the use of EAUS in cases of anal sphincter defects, 11 anal fistulas, 12 perianal abscesses, 13 and anal tumors. 14 However, we found only a single study in the literature that studied anal sphincter anatomy in patients with hemorrhoids. ...
... It utilizes various acoustic impedance by placing a transducer externally to the abdominal wall. It is considered a more suitable scanning method that can be conducted on an animal in a standing position without the stress of anesthesia (Kim 2015;Kurzweil and Martin 2020). Given that the use of transabdominal ultrasonography has not yet been reported in anoas (Jones et al. 2016;Schmid et al. 2016), the aim of the current study was to evaluate the reliability of urine biochemical profiles and transabdominal ultrasonography as a minimal invasive method for early pregnancy detection and EBP validation, respectively, in anoas. ...
Bowolaksono A, Mayasari A, Sundari AM, Simamora ATJ, Suryaningsih R, Suryawan A, Simamora ATJ, Abinawanto, Sjahfirdi L, Hasna A, Supriatna J, Kyes RC. 2022. Urine biochemical profile analysis and transabdominal ultrasonography for pregnancy detection in the endangered lowland anoa (Bubalus depressicornis). Biodiversitas 23: 6056-6061. The population of lowland anoas (Bubalus depressicornis) has decreased significantly due to illegal hunting and habitat loss. As such, the urgency in developing successful ex-situ conservation programs cannot be overstated. Ex-situ breeding programs of anoas, however, are hindered by difficulties in early pregnancy detection. The failure to detect pregnancy at an early stage often results in miscarriage due to repeated breeding attempts of unconfirmed pregnant females. Moreover, frequent false heat during 5 to 6 months of pregnancy corroborated the repeated breeding of pregnant females. Therefore, early detection techniques are needed to improve breeding success. The present study evaluated the use of urine biochemical profiles as a minimally invasive approach for early pregnancy detection and transabdominal ultrasonography as a confirmation tool of false heat in four lowland anoas. Statistical analysis showed that glucose and protein level were significantly elevated during pregnancy since the 0 days of post-mating (p<0.05) and consistently higher compared to the non-pregnant period. Meanwhile, transabdominal ultrasonography successfully identified organ structures and development by the 155th, 176th, 180th, and 191st days of pregnancy. The present study suggests that urine biochemical data provide a promising, minimally invasive approach to early pregnancy detection in anoas. Incorporating urine data and ultrasonography can significantly help to maintain pregnancy by validating false heat.
... The hypo-echoic tract (arrows) is seen amid the interior (IAS) and exterior anal sphincters (EAS) (Inter-sphincteric Peri-anal fistula) (33). ...
... EAUS is a safe and economical technique that can also be used in patients who cannot undergo MRI because of claustrophobia, obesity, or metallic implants (such as pacemakers [8]. ...
Background
Perianal fistula is a considered as chronic recurrent inflammatory condition that requires proper surgical treatment and may require repeated intervention. Therefore, adequate pre-operative radiological diagnosis plays a critical role.
In this study, we aimed at comparing the role of endoanal ultrasonography with MRI fistulography in evaluating the primary fistula's tract, internal opening, secondary extensions, and complications of the perianal fistula.
Results
The study was carried over 108 males (90%) and 12 females (10%) presenting with clinically diagnosed perianal fistula. Ultrasound was found superior to MRI in the localization of the internal opening with estimated K value (0.44), P value (0.001). Regarding the type of fistula, ultrasound was found in agreement with MRI in 112 cases (93.3%) with estimated K value of about (0.7). Ultrasound was found equally effective as MRI in the detection of complication with estimated agreement K value of about 1. Regarding assessment of the secondary extensions, the agreement between the two modalities was about 50% with estimated k value of about 0.65. Conversely, MRI was found superior to ultrasound in the characterization of the fibrotic tracts.
Conclusions
Both EAUS and MRI have a crucial role in the evaluation and detection of perianal fistulas. EAUS was preferable to MRI in the localization of the internal opening; ,conversely, in the evaluation of extra-sphincteric fistulas and fibrotic tracts characterization MRI was preferable to EAUS.
