Anal perianal imaging part 4 perianal fistula ct mri dr ahmed esawy Anal perianal imaging part 1 ct mri anatomy dr ahmed esawy ANAL ,PERIANAL IMAGING (endovaginal ultrasound endoanal ultrasound perineal ultrasound MRI) FOR ANAL ,PERIANAL DISEASE3/ Image reconstruction and processing artifacts • ANAL ANATOMY • ANAL PERIANAL FISTULA • ANAL TEARS (OBSTETRIC) • FAECAL INCONTINENCE • OTHER DISEASES • NATOMY ANORECTAL ANATOMY : • Anal Sphincter: • internal sphincter • external sphincter • Puborectalis muscle and levator ani • Sub cutaneous perianal fistula • Sub mucous perianal fistula • Low anal perianal fistula • High anal perianal fistula • Pelvi rectal perianal fistula • Simple fistulography • Perianal fistulography • Endosonography Perianal fistula • A. A superficial fistula. • B. An intersphincteric fistula. • C. A transsphincteric fistula. • D. A suprasphincteric fistula. • E. An extrasphincteric fistula. •

1. Dr Ahmed Esawy
ANAL PERIANAL IMAGING
Dr. Ahmed Esawy
MBBS M.Sc MD

2. Dr Ahmed Esawyyour name
ANAL ,PERIANAL IMAGING
(endovaginal ultrasound
endoanal ultrasound
perineal ultrasound
MRI)
FOR ANAL ,PERIANAL
DISEASE

3. Dr Ahmed Esawy
Faecal
Incontinence

4. Dr Ahmed Esawy
PREVALENCE SYMPTOM
INCONTINENCE AFTER
REPAIR
Incontinence symptom 25 - 75%
Flatus 30%
Liquid stool 8%
Solid stool 4%
Fecal urgency 26%

5. Dr Ahmed Esawy
Etiology Occult damage or defect
anal sphincter
• Very few understood anatomy of perineum
and anal sphincter
• Inadequate training to repair anal sphincter
tear skill)
• Standard classification is different than
RCOG-WHO classification.
• Method repair (end to end or overlap)
• Suture material: cat gut or poliglactin
(vicryl) or monofilaments (Polydioxanone)
• Postoperative care : in adequate

6. Dr Ahmed Esawy
Faecal incontinence
EAUS when performed by an experienced clinician approaches 100%
sensitivity and specificity in identifying internal and external sphincter defects.
Scanning here should be performed at different levels by gently moving the
probe in and out of the anal canal to achieve:
Discovery of discontinuity of either IAS or EAS muscle which is considered as
evidence of a sphincteric defect.
Measurement of the extent of defect in external or internal sphincter in two
directions; longitudinally in form of its distance from sonographic anal verge and
transversely for determination of extent of the defect in anal circumference
(Robert et al., 2002).

7. Dr Ahmed Esawy
Factors influencing normal continence :
The consistency of the stool .
The capacity of the rectum.
The preservation of a normal sampling reflux
Normal anorectal sensation.
Normal resting anal tone.
An intact innervated striated puborectalis and external anal sphincter muscles.

8. Dr Ahmed Esawy
• The normal IAS is between 2 to 3 mm thick and the
normal EAS in between 4 to 5 mm thick.
• The IAS becomes thicker and more hyperechoic with
age, probably reflecting collagen replacement.
Conversely, the EAS tends to become thinner with
age
• For female patients being evaluated for faecal
incontinence, the examination is occasionally
performed with the patient in the prone position to
more clearly delineate the anterior aspect of the EAS
and improve visualization of the perineum.

9. Dr Ahmed Esawy
The role of EAUS in faecal incontinence is specifically related to the detection of
anal sphincter lesions including tear, scarring, thinning and atrophy
tear' is used to indicate any discontinuity in the sphincter layer, which is seen as a
break of the normal echotexture and geometrical configuration
scarring' relates to the presence of focal changes in echogenicity, which alter the
expected normal pattern. '
Thinning' and ''atrophy are virtually synonymous at sonography, which has no other
criteria than a reduction in the thickness of the muscle bulk to make the diagnosis

10. Dr Ahmed Esawy
Fecal incontinence
Fecal incontinence is the inability to
control the passage of gas,liquid or
solid through the anus.
Third/ Fourth perineal tear vaginal
delivery where mediolateral
episiotomy is performed. 0.6-9%
Occult damage or defect sphincter
(endoanal ultrasound evaluation).

11. Dr Ahmed Esawy
EAUS in cases of faecal
incontinence
Preoperative Assessment:
85-90% of women with post obstetric incontinence will have a sphincter defect evident
on EAUS. The most frequent abnormality is a defect of the EAS that commences at the
level of perineal body and may or may not extends to involve IAS as well
EAUS is also used in evaluation of patients who develop incontinence after
sphincterotomy, fistulotomy, or anal stretch procedures. EAUS demonstrates that the
sphincterotomy is more extensive than intended and extends for the entire length of the
anal canal (this is more common in women because they have a shorter anal canal)
(Sultan et al., 1993).

12. Dr Ahmed Esawy
Appearance of anal sphincter defects
In cases of disruption of either of the sphincteric muscles there seems to be wide
separation of the muscular ends which appears as:
External sphincter defect is recognized as discontinuity of the normal muscle
pattern with areas of hyperechoic, or hypoechoic, and or mixed echogenicity
merging on either side into normal muscle which makes the remainder of the
external sphincter ring.
Internal sphincter disruption appears as a discontinuity in the very hypoechoic band
in the field. This is believed to be caused by scarring which gives hyperechoic
pattern (Sultan et al., 1994).
Endoanal US image in a 53-
year-old woman with fecal
incontinence shows a defect
(solid arrows) of the external
sphincter (ES) and a defect
(open arrows) of the internal
sphincter (IS) (Quoted from
Elena et al, 1999).

13. Dr Ahmed Esawy
3-D built-in EAUS of the anal canal with automatic image acquisition, allowing
a volume of digital data to be examined: a 12-to-5 o’clock wide defect (space
between the two arrows) is seen in the internal anal sphincter together with
hypertrophy of the remaining portion

14. Dr Ahmed Esawy
Two-dimensional (2-D) translabial imaging of the anal canal obtained with a 3.5 MHz
convex probe showing . the continuous hypoechoic ring of internal anal sphincter (black
arrow), the hyperechoic submucosa (red arrow) and the “X-shaped” hypoechoic mucosa
(blue arrow) in the axial view (a) and in the sagittal view (b)

15. Dr Ahmed Esawy
At EAUS, defects in the IAS appear as hyperechoic breaks in the normally
hypoechoic ring, as opposed to defects in the EAS, which appear as relatively
hypoechoic areas in the normally hyperechoic ring

16. Dr Ahmed Esawy
Close-up view of the anal sphincters at EAUS in the axial plane from two different
patients: typical sonographic feature of the internal (a) and the external (b) anal
sphincter defect which are seen as wide gaps (parenthesis) filled by fibrotic tissue
showing moderate echogenicity and inhomogeneous hypoechogenicity,
respectively.

17. Dr Ahmed Esawy
Sixty-two year-old woman under pharmacological treatment for psychological
depression, with history of obstetric trauma, chronic constipation and episodes of
passive fecal incontinence of recent onset. Integrated diagnostic work-up including
perineal sonography (a) and defecography (b) within the same session: at sonography,
thinning of the internal anal sphincter (short arrow) on straining and significant increase
of the submucosal space (long arrow) suggestive of full-thickness intussusception. At
defecography, involuntary barium loss during retrograde injection (not shown) and
evidence of rectoanal intussusception with typical “Saturn’s ring” sign due to entrapment
of contrast on emptying within the double layer mucosa infolding.

18. Dr Ahmed Esawy
Postoperative assessment
to evaluate the efficacy of repair in cases of:
Incomplete sphincter repair or muscle disruption following sphincter repair
Showing efficient sphincter repaire in recently repaired patient (overlapping
appearance of internal anal sphincter)
(Quoted from section 6th surgery, Demerdash Hospital)
Comparison between preoperative and postoperative studies augments the
assessment of the efficacy of the repair (Speakman et al.,1991).

19. Dr Ahmed Esawy
Diagnostic Criteria: the MR diagnosis of anal sphincter derangement in faecal
incontinence is
two-fold and relies on:
1) a < 2 mm thinning of the internal anal sphincter for age > 50 years,
which is considered consistent with degeneration of the muscle and responsible for
passive faecal incontinence;
2) disruption of the sphincteric ring with or without loss of striated muscle bulk and fat
replacement, which are typical findings of external sphincter tears and atrophy
most often associated with childbirth trauma, incisional surgery and dilatation
procedures.

20. Dr Ahmed Esawy
In symptomatic patients, pelvic organs descent greater than 2 cm below the PCL is
considered an indication of pelvic floor laxity, requiring surgical intervention. More
precisely,
quantification of pelvic organ prolapse by MR imaging has been classified
mild if the vertical distance from the PCL on maximum straining extends for less
than 3 cm (grades 1-2 of the Baden-Walker classification),
moderate if it is between 3 and 6 cm (Baden-Walker grade 3)
and severe if it exceeds 6 cm (Baden-Walker grade 3-4)
characterization of the dysfunction and evidence of pelvic organ impingement
can be derived from a levator hiatus area of 30-34.9 cm2 (mild),35-39.9 cm2
(moderate) and ≥40 cm2 (marked ballooning)
rectocele, which is classified as mild when its protrusion from the expected anterior
rectal wall is less than 2 cm, moderate if 2-4 cm and severe if greater than 4 cm
intussusception, which is termed intrarectal (grade 1) when it remains within the
rectum, intra-anal (grade 2) if its apex penetrates the proximal half of the anal canal,
intra-anal (grade 3), if the apex is seen to impinge on the distal half of the anal canal
and external (grade 4) if it is extruded outward

21. Dr Ahmed Esawy
Forty-eight-year-old man with prior fistulotomy (red arrow) and no evidence of fecal
incontinence. Postoperative mid coronal T 2-weighted MRI with external coil showing
preserved integrity of the sphincter complex including the internal sphincter (sky-blue
arrow), the external sphincter (black arrow), and the longitudinal muscle (green arrow).
Incidentally, focal areas of increased signal intensity are observed within the
puborectalis muscle (yellow arrow)
consistent with fibrofatty degeneration.

22. Dr Ahmed Esawy
MR- defecographic images obtained in the coronal (a) and axial(b) plane in a sixty-
one-year-old woman with persistent fecal incontinence after multiple gate keeper
implants (red arrows) for degeneration of the internal sphincter and
atrophy/disruption of the external sphinter: involuntary loss of contrast and lack of
anal wall apposition (yellow arrow).

23. Dr Ahmed Esawy
Mid- sagittal MR-defecographic series with BFFE T 1-weighted pulse sequence:
excessive descent of the bladder base (short red arrow) and rectal floor (long red
arrow) on straining below the pubococcygeal line (yellow dotted line) due to pelvic
floor laxit y in a thirty-one year-old woman with chronic strain at stool and staining
episodes

24. Dr Ahmed Esawy
Dynamic MR- defecography in the axial plane at the level of the lower margin of the
symphysis pubis: ballooning of the levator hiatus with impingement of the uterine
cervix (red arrow) between the prolapsed bladder base,anteriorly and the
anorectum, posteriorly.

25. Dr Ahmed Esawy
Transverse T2-weighted fast spin-echo (a) endoanal and (b) external MR images
show normal anatomy and normal continuity of both the external anal sphincter (ES)
ring and internal anal sphincter (IS) ring in a 77-year-old man with fecal incontinence
and no prior anorectal surgery.

26. Dr Ahmed Esawy
Transverse T2-weighted fast spin-echo (a) endoanal and (b) external phased-array
MR images show extensive scar tissue (arrowheads) at the right lateral to left part
(9- through 5-o’clock positions) of the external anal sphincter (ES) in a 55-year-old
woman with fecal incontinence. This patient had three risk factors (long stage of
labor, instrumental delivery, episiotomy) for anal sphincter trauma during vaginal
delivery in the past.

27. Dr Ahmed Esawy
(a) Transverse endoanal T2-weighted fast spin-echo MR image shows at the anterior
part of the external anal sphincter discontinuity of the anal sphincter ring (black
arrowheads) and scar tissue (white arrowheads). All observers scored a defect of the
anterior external anal sphincter. (b) Transverse external phased-array T2-weighted fast
spin-echo (2500/70) MR image shows some irregularity at the anterior part of the
external anal sphincter. Two of three observers did not score external anal sphincter
defect. Endoanal US depicted anterior external anal sphincter defect. IS internal anal

28. Dr Ahmed Esawy
(a) endoanal and (b) external phased-array MR images do not show a clear
demarcation between the anterior external anal sphincter and the directly aligned
posterior vaginal wall. None of the observers scored external anal sphincter defect at
endoanal MR imaging. Two of three observers scored anterior external anal sphincter
defect (arrowheads) at external phased-array MR imaging. Endoanal US depicted
anterior external anal sphincter defect. IS internal anal sphincter.

29. Dr Ahmed Esawy
DISRUPTION OF THE INTERNAL ANAL SPHINCTER

30. Dr Ahmed Esawy
DISRUPTION OF THE EXTERNAL ANAL SPHINCTER

31. Dr Ahmed Esawy
REPAIR TYPE
• END TO END (OBSTETRIC)
• OVERLAP (COLORECTAL SURGEON)

32. Dr Ahmed Esawy
INFLAMMATORY
DISEASE

33. Dr Ahmed Esawy
Spontaneous perianal inflammatory disease in two patients.
A, Axial transperineal image in 32-year-old man shows internal opening at 6-o’clock position
posteriorly (arrowhead). Transsphincteric hypoechoic tract runs through sphincter and then shows
extension to both right and left (arrows). Tract could be followed to external opening on right buttock
(not shown).
B, Transperineal sagittal image obtained with linear probe placed on skin immediately lateral to anal
canal in 50-yearold man who presented with perianal pain and no external opening shows anal
canal (AC) in median view as hypoechoic band. Air-containing abscess (A) communicates with anal
canal at its mid point posteriorly. There was no tract to skin

34. Dr Ahmed Esawy
Sonogram shows contribution of 3D volume acquisition to assessment of
transsphincteric fistula in 44-year-old woman with no history of inflammatory bowel
disease. Three-dimensional volume was achieved in transverse plane (not shown).
Coronal reconstruction
image shows entire course of fistulous tract (arrows),which ascends inside of
sphincter before crossing through sphincter to descend outside of sphincter to
perineum.

35. Dr Ahmed Esawy
Complex and extensive perianal abscesses in 35-year-old woman with known Crohn’s
disease.
A, Transvaginal axial image of anal canal shows large internal opening (arrow) at 6-
o’clock position posteriorly.Transsphincteric tract runs to bilobed horseshoe abscess
with components to right and left of anal canal.
B, Obtained at slightly different location, image shows additional deep, lobulated fluid-
containing abscess on left side

36. Dr Ahmed Esawy
Adenocarcinoma complicating chronic fistula in 61-year-old man with Crohn’s
disease.
A, Transperineal low axial image shows anal canal in cross section. Posterior to
canal, well-defined and solidappearing mass (arrows) is seen.
B, Transanal transverse color Doppler sonogram confirms solid and vascular
mass totally engulfs the seton, which shows here as echogenic focus with
shadowing (arrow). Tumor arises from mucosa, and complete destruction of wall
layers is shown.

37. Dr Ahmed Esawy
Biopsy-proven chronic inflammatory mass in symptomatic 47-year-old man with
rectal pain, unchanged over 3-year interval. No evidence of cancer or Crohn’s
disease was seen either clinically or on biopsy.
A, Endorectal axial sonogram shows heterogeneous hypoechoic mass mimicking
rectal cancer. Wall layers are destroyed.
B, Addition of color Doppler sonogram shows mild hypervascularity of mass.

38. Dr Ahmed Esawy
Pouchitis and anastomotic inflammatory mass in 48-year-old woman with total
colectomy for ulcerative colitis and ileoanal anastomosis.
A, Transvaginal image of pouch (P) shows that it is thick walled, distended with
liquid stool, and surrounded by excessive echogenic inflammatory fat (F).
B, Axial image taken with transvaginal probe shows region of ileoanal anastomosis.
There is hypoechoic masslike area within thickened anterior wall.
C, Addition of color Doppler sonogram shows profuse hypervascularity in this
inflammatory mass. This patient responded to conservative management.
Pouchogram (not
shown) obtained 1 month later did not show leak and follow-up sonogram (not
shown) showed normal appearance.

39. Dr Ahmed Esawy
ANAL TUMOURS

40. Dr Ahmed Esawy
T1 tumor. Endorectal US scan shows focal thickening of the hypoechoic muscularis
mucosa layer (white arrows) in the anterior rectal wall. The hyperechoic submucosal
layer clearly separates the tumor from the hypoechoic muscularis propria layer (black
arrows) (Quoted from Jonathan et al., 1998).

41. Dr Ahmed Esawy
T2 tumor. Endorectal US scan shows marked thickening of the muscularis
mucosa (small arrow) and muscularis propria (arrowhead) layers with focal
nodularity (large arrows) that appears to extend into the perirectal fat
(Quoted from Jonathan et al., 1998).

42. Dr Ahmed Esawy
T3tumor. Endorectal US scan shows marked thickening of
the muscularis mucosa and muscularis propria layers with
actual invasion into the perirectal fat. (Quoted from
Jonathan, et al., 1998)

43. Dr Ahmed Esawy
T4tumor. Endorectal US scan shows marked thickening of all layers of rectal wall
with invasion also to out side and to a near by hypoechoic lymph node (Quoted
from Jonathan et al., 1998).

44. Dr Ahmed Esawy
Well defined mass extended from 11-2 o'clock with preserved middle white
line; benign villous adenoma of the rectum (Quoted from Nivatvongs, et
al., 1999).

45. Dr Ahmed Esawy
Pitfalls in the use of EUS:
Technical pitfalls:
During endoanal examination:
Lesions near or at the anal verge can easily be missed because the
balloon on the transducer tip will not pass through the normal sphincter
and should be deflated that gives poor demonstration
During endorectal examination:
Technical artifacts arise from:
Limited space available for maneuvering the endorectal transducer.
The need to keep the transducer perpendicular to the tortuous rectal wall.
The need to establish an adequate acoustic interface between the transducer
tip and rectal wall.
Attenuation differences between large tumors and adjacent normal tissue
Additional limitations are associated with the use of rigid transducers, which
have restricted depth of penetration from the anal verge 10-12cm only and
difficulty in penetration through stenosed tumor (Sabine et al., 2004).
Balloon inflation:
Over inflating the balloon may cause overcompression of the rectal wall and
lead to overestimation of tumor penetration.
Under inflating the balloon may cause balloon-rectal wall separation and
artifacts.
Stenotic lesions do not permit adequate balloon distention (Hulsman, et al.,

46. Dr Ahmed Esawy
Pitfalls in the use of EUS
Technical pitfalls
Transducer angle and location
Shadowing artifacts due to air
Shadowing artifacts due to stool
Reverberation artifacts (Reverberation artifacts occur when the ultrasound beam is
strongly reflected (by air, metal clips, or air filled stool) which reflected again to the
transducer surface ,and re-enters the patient so it is interpreted as another
object ,resulting in a series of equally spaced echoes distal to the reflector surface (
Refraction artifacts
Transducer Gain settings

47. Dr Ahmed Esawy
Shadowing artifacts due to stool: EUS imag shows circumferential
shadowing obscuring the bowel wall due topresence of stool throughout
the rectum coating the bowel wall

48. Dr Ahmed Esawy
Staging pitfalls
Interpretation differences
Tumor location
Stenotic tumors
Peritumoral inflammation
Post biopsy changes & Hemorrhage
Radiation therapy
Predicting lymphatic involvement (Lymph nodes may be over-or under estimated for
several reasons: Micro metastases do not cause nodal enlargement.
Lateral pelvic nodes are not seen with endorectal transducer.
Inflammatory nodes frequently simulate metastatic nodes.
Nodal size is not a reliable predictor of tumor invasion (approximately 18% of
nodes less than 5mm in diameter harbor metastases).
Therefore use of size criteria alone for nodal involvement results in a high false
negative rate, whereas use of node appearance alone results in a high false positive
rate
Rectal wall lesions mimicking rectal cancer

49. Dr Ahmed Esawy
Presacral cyst

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Presacral cyst

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