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Transrectal ultrasonography of anorectal diseases: advantages and disadvantages.

Kim MJ - Ultrasonography (2014)

Bottom Line: It provides excellent visualization of the layers of the rectal wall and of the anatomy of the anal canal.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea.

ABSTRACT
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 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.

No MeSH data available.


Related in: MedlinePlus

Extrasphincteric perianal fistula.A. An axial three-dimensional ultrasonogram shows that the hypoechoic tract (arrow) lies along the intersphincteric space, extending into the external anal sphincter (EAS). B. The hypoechoic tract (arrows) passes from the intersphincteric space through the external sphincter into the ischiorectal fossa on coronal image.
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f11-usg-14051: Extrasphincteric perianal fistula.A. An axial three-dimensional ultrasonogram shows that the hypoechoic tract (arrow) lies along the intersphincteric space, extending into the external anal sphincter (EAS). B. The hypoechoic tract (arrows) passes from the intersphincteric space through the external sphincter into the ischiorectal fossa on coronal image.

Mentions: Perianal fistulas appear as hypoechoic tracts or focal soft tissue lesions within anal wall structures (Video clips 1, 2). Abscesses may contain internal gas or hyperechoic debris, and fistulas show a narrow and irregular path on TRUS (Figs. 10, 11, Video clip 3). Depending on the internal composition or stage of inflammation, the primary fistula tract appears as variable echogenic fluid with a thickened wall (Fig. 12). Compared to an active anal fistula containing fluid-like material, inactive fistulas are tubular fibrotic bands without fluid content. The fistula tract extends through the perianal spaces while crossing the subepithelium, internal, or external sphincter [37]. TRUS provides excellent imaging of the rectal wall layers and anal sphincter, and therefore is excellent at visualizing intersphincteric fistulas and their relationship to the anal canal [1,33]. TRUS with a high frequency transducer (81%) has been shown to be more accurate than digital examination (61%) in 108 primary fistula tracts [38]. A meta-analysis reported the sensitivity and specificity of TRUS in the detection of fistulas as 0.87 (95% confidence interval, 0.70 to 0.95) and 0.43 (95% confidence interval, 0.21 to 0.69) [39]. High-resolution 3D US is potentially a useful tool for accurately assessing fistula tracts. The operator can trace the tract by reconstructing all necessary planes from the US images. 3D imaging has improved the accuracy to 98.5% for primary tracts and 96.4% for secondary tracts, compared to accuracies of 83.3% and 87.9%, respectively, for 2D imaging [40].


Transrectal ultrasonography of anorectal diseases: advantages and disadvantages.

Kim MJ - Ultrasonography (2014)

Extrasphincteric perianal fistula.A. An axial three-dimensional ultrasonogram shows that the hypoechoic tract (arrow) lies along the intersphincteric space, extending into the external anal sphincter (EAS). B. The hypoechoic tract (arrows) passes from the intersphincteric space through the external sphincter into the ischiorectal fossa on coronal image.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4282231&req=5

f11-usg-14051: Extrasphincteric perianal fistula.A. An axial three-dimensional ultrasonogram shows that the hypoechoic tract (arrow) lies along the intersphincteric space, extending into the external anal sphincter (EAS). B. The hypoechoic tract (arrows) passes from the intersphincteric space through the external sphincter into the ischiorectal fossa on coronal image.
Mentions: Perianal fistulas appear as hypoechoic tracts or focal soft tissue lesions within anal wall structures (Video clips 1, 2). Abscesses may contain internal gas or hyperechoic debris, and fistulas show a narrow and irregular path on TRUS (Figs. 10, 11, Video clip 3). Depending on the internal composition or stage of inflammation, the primary fistula tract appears as variable echogenic fluid with a thickened wall (Fig. 12). Compared to an active anal fistula containing fluid-like material, inactive fistulas are tubular fibrotic bands without fluid content. The fistula tract extends through the perianal spaces while crossing the subepithelium, internal, or external sphincter [37]. TRUS provides excellent imaging of the rectal wall layers and anal sphincter, and therefore is excellent at visualizing intersphincteric fistulas and their relationship to the anal canal [1,33]. TRUS with a high frequency transducer (81%) has been shown to be more accurate than digital examination (61%) in 108 primary fistula tracts [38]. A meta-analysis reported the sensitivity and specificity of TRUS in the detection of fistulas as 0.87 (95% confidence interval, 0.70 to 0.95) and 0.43 (95% confidence interval, 0.21 to 0.69) [39]. High-resolution 3D US is potentially a useful tool for accurately assessing fistula tracts. The operator can trace the tract by reconstructing all necessary planes from the US images. 3D imaging has improved the accuracy to 98.5% for primary tracts and 96.4% for secondary tracts, compared to accuracies of 83.3% and 87.9%, respectively, for 2D imaging [40].

Bottom Line: It provides excellent visualization of the layers of the rectal wall and of the anatomy of the anal canal.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea.

ABSTRACT
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 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.

No MeSH data available.


Related in: MedlinePlus