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Diagnostic imaging features of normal anal sacs in dogs and cats

View Article: PubMed Central - PubMed

ABSTRACT

This study was conducted to provide normal reference features for canine and feline anal sacs using ultrasound, low-field magnetic resonance imaging (MRI) and radiograph contrast as diagnostic imaging tools. A total of ten clinically normal beagle dogs and eight clinically normally cats were included. General radiography with contrast, ultrasonography and low-field MRI scans were performed. The visualization of anal sacs, which are located at distinct sites in dogs and cats, is possible with a contrast study on radiography. Most surfaces of the anal sacs tissue, occasionally appearing as a hyperechoic thin line, were surrounded by the hypoechoic external sphincter muscle on ultrasonography. The normal anal sac contents of dogs and cats had variable echogenicity. Signals of anal sac contents on low-field MRI varied in cats and dogs, and contrast medium using T1-weighted images enhanced the anal sac walls more obviously than that on ultrasonography. In conclusion, this study provides the normal features of anal sacs from dogs and cats on diagnostic imaging. Further studies including anal sac evaluation are expected to investigate disease conditions.

No MeSH data available.


Dorsal sonographic and diagram (A) of canine anal sac. Dorsal schematic sonograph image (B) of canine anal sac. Anal sac tissue (glands) appears as a hyperechoic thin line (arrow). Dorsal sonographic images of feline anal sac (C). The appearance of the anal sac was round, and their contents appear hypoechoic to similar to external sphincter muscle. Asterisks, anal sac contents; e, external sphincter muscle; r, rectum.
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Figure 4: Dorsal sonographic and diagram (A) of canine anal sac. Dorsal schematic sonograph image (B) of canine anal sac. Anal sac tissue (glands) appears as a hyperechoic thin line (arrow). Dorsal sonographic images of feline anal sac (C). The appearance of the anal sac was round, and their contents appear hypoechoic to similar to external sphincter muscle. Asterisks, anal sac contents; e, external sphincter muscle; r, rectum.

Mentions: The anal sacs were located on both sides of the rectum on dorsal images (panel A in Fig. 4). Similar to radiography, the dog anal sacs were ellipsoidal, whereas the cat anal sacs were rounder. Most surfaces of the anal sac tissue were surrounded by the hypoechoic external sphincter muscle. The anal sac tissue occasionally appeared as a hyperechoic thin line (panel B in Fig. 4). The normal anal sac contents of dogs and cats varied in echogenicity. Contents generally appeared hypoechoic with diffuse point-like hyperechoic debris, and the contents of cat anal sacs were more often hyperechoic (panel C in Fig. 4).


Diagnostic imaging features of normal anal sacs in dogs and cats
Dorsal sonographic and diagram (A) of canine anal sac. Dorsal schematic sonograph image (B) of canine anal sac. Anal sac tissue (glands) appears as a hyperechoic thin line (arrow). Dorsal sonographic images of feline anal sac (C). The appearance of the anal sac was round, and their contents appear hypoechoic to similar to external sphincter muscle. Asterisks, anal sac contents; e, external sphincter muscle; r, rectum.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037300&req=5

Figure 4: Dorsal sonographic and diagram (A) of canine anal sac. Dorsal schematic sonograph image (B) of canine anal sac. Anal sac tissue (glands) appears as a hyperechoic thin line (arrow). Dorsal sonographic images of feline anal sac (C). The appearance of the anal sac was round, and their contents appear hypoechoic to similar to external sphincter muscle. Asterisks, anal sac contents; e, external sphincter muscle; r, rectum.
Mentions: The anal sacs were located on both sides of the rectum on dorsal images (panel A in Fig. 4). Similar to radiography, the dog anal sacs were ellipsoidal, whereas the cat anal sacs were rounder. Most surfaces of the anal sac tissue were surrounded by the hypoechoic external sphincter muscle. The anal sac tissue occasionally appeared as a hyperechoic thin line (panel B in Fig. 4). The normal anal sac contents of dogs and cats varied in echogenicity. Contents generally appeared hypoechoic with diffuse point-like hyperechoic debris, and the contents of cat anal sacs were more often hyperechoic (panel C in Fig. 4).

View Article: PubMed Central - PubMed

ABSTRACT

This study was conducted to provide normal reference features for canine and feline anal sacs using ultrasound, low-field magnetic resonance imaging (MRI) and radiograph contrast as diagnostic imaging tools. A total of ten clinically normal beagle dogs and eight clinically normally cats were included. General radiography with contrast, ultrasonography and low-field MRI scans were performed. The visualization of anal sacs, which are located at distinct sites in dogs and cats, is possible with a contrast study on radiography. Most surfaces of the anal sacs tissue, occasionally appearing as a hyperechoic thin line, were surrounded by the hypoechoic external sphincter muscle on ultrasonography. The normal anal sac contents of dogs and cats had variable echogenicity. Signals of anal sac contents on low-field MRI varied in cats and dogs, and contrast medium using T1-weighted images enhanced the anal sac walls more obviously than that on ultrasonography. In conclusion, this study provides the normal features of anal sacs from dogs and cats on diagnostic imaging. Further studies including anal sac evaluation are expected to investigate disease conditions.

No MeSH data available.