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13 Magnetic Resonance Imaging in the Diagnosis, Characterization, and.. . 209
each depicted by different colors (Sahnan et al. 2018b). While 3D recreations of
imaging have been shown to be effective in helping surgeons understand complex
pelvic anatomy and prepare for operations, they may also be used to help patients
understand their disease. Perianal Crohn’s patients are often young and wellinformed about their condition, having gone through multiple surgeries throughout
their lifetime (Cheifetz 2013). This 3D reconstruction would allow patients to better
understand the details of operations and allow them to participate more meaningfully
in shared decision-making regarding management.
One of the drawbacks to creating 3D reconstructions from MRI images is the
need for manual segmentation of each structure. The levator ani, external and
internal anal sphincters, and fistula tracts must be segmented by the radiologist
which will take time. While currently requiring manua l segmentation, previous
studies have shown automatic segmentation in MRI in different tissues (Lee et al.
2017; Rincón et al. 2017), including in abdominal MRI to detect luminal Crohn’s
disease (Mahapatra et al. 2013). 3D modeling, once automatic segmentation
develops further for fistula, may become the standard of care in managing fistula
and communicating disease details with patients.
7 Conclusion
MRI represents the most effective imaging option for accurately characterizing the
relevant anatomy in perianal Crohn’s disease. Along with its capacity to reliably
diagnose and characterize a fistulizing disease, it has also been shown to be effective
in objectively monitoring disease activity and shows promise as a tool to improve
operative planning and surgical training.
8 Cross-References
▶ Clinical Assessment of Crohn Perianal Abscesses and Fistulas
▶ Evidences for Optimal Surgical Management of Anal Fistulas and Abscesses
▶ Magnetic Resonance and Traditional Radiology in the Diagnosis of Crypto-
glandular Anal Fistula and Abscess
References
Adegbola SO et al (2018) Medical and surgical management of perianal Crohn’s disease. Ann
Gastroenterol 31:129–139
Adegbola SO et al (2020) Current review of the management of fistulising perianal Crohn’s disease.
Frontline Gastroenterol. https://doi.org/10.1136/flgastro-2020-101489
Barnhoorn MC et al (2020) Long-term evaluation of allogeneic bone marrow-derived mesenchymal
stromal cell therapy for Crohn’s disease perianal fistulas. J Crohns Colitis 14:64–70
Beckingham IJ et al (1996) Prospective evaluation of dynamic contrast enhanced magnetic reso-
nance imaging in the evaluation of fistula in ano. Br J Surg 83:1396–1398
210 M. Vincent et al.
Beets-Tan RGH et al (2001) Preoperative MR imaging of anal fistulas: does it really help the
surgeon? Radiology 218:75–84
Bianchi L et al (2019) 3D reconstruction and physical renal model to improve percutaneous punture
during PNL. Int Braz J Urol 45:1281–1282
Buchanan G et al (2002) Effect of MRI on clinical outcome of recurrent fistula-in-ano. Lancet 360:
1661–1662
Buchanan GN et al (2004) Clinical examination, endosonography, and MR imaging in preoperative
assessment of fistula in ano: comparison with outcome-based reference standard. Radiology
233:674–681
Chambaz M et al (2019) Deep remission on magnetic resonance imaging impacts outcomes of
perianal fistulizing Crohn’s disease. Dig Liver Dis 51:358–363
Cheifetz AS (2013) Management of active Crohn disease. JAMA 309:2150
Choen S, Phillips RKS (1991) Insights gained from the management of problematical anal fistulae
at St. Mark’s Hospital, 1984–88. Br J Surg 78:539–541
Dagia C, Ditchfield M, Kean M, Catto-Smith A (2010) Feasibility of 3-T MRI for the evaluation of
Crohn disease in children. Pediatr Radiol 40:1615–1624
Darbari A et al (2004) Gadolinium-enhanced magnetic resonance imaging: a useful radiological
tool in diagnosing pediatric IBD. Inflamm Bowel Dis 10:67–72
Essary B, Kim J, Anupindi S, Katz AJ, Nimkin K (2007) Pelvic MRI in children with Crohn disease
and suspected perianal involvement. Pediatr Radiol 37:201–208
Garros A et al (2014) Magnetic resonance imaging and clinical assessments for perianal Crohn’s
disease: gain and limits. Dig Liver Dis 46:1072–1076
Gionchetti P et al (2017) 3rd European evidence-based consensus on the diagnosis and management
of Crohn’s disease 2016: Part 2: surgical management and special situations on behalf of ECCO.
J Crohns Colitis 11:135–149. https://doi.org/10.1093/ecco-jcc/jjw169
Hindryckx P et al (2019) Development and validation of a magnetic resonance index for assessing
fistulas in patients with Crohn’s disease. Gastroenterology 157:1233–1244.e5
Horsthuis K et al (2011) Evaluation of an MRI-based score of disease activity in perianal fistulizing
Crohn’s disease. Clin Imaging 35:360–365
Jones J, Tremaine W (2005) Evaluation of perianal fistulas in patients with Crohn’s disease.
MedGenMed 7:16
Keighley MR, Allan RN (1986) Current status and influence of operation on perianal Crohn’s
disease. Int J Color Dis 1:104–107
King D et al (2020) Changing patterns in the epidemiology and outcomes of inflammatory bowel
disease in the United Kingdom: 2000–2018. Aliment Pharmacol Ther 51:922–934
Laghi A et al (2003) Contrast enhanced magnetic resonance imaging of the terminal ileum in
children with Crohn’s disease. Gut 52:393–397
Lee H et al (2017) Fully automated deep learning system for bone age assessment. J Digit Imaging
30:427–441
Li P et al (2018) The 3D reconstructions of female pelvic autonomic nerves and their related organs
based on MRI: a first step towards neuronavigation during nerve-sparing radical hysterectomy.
Eur Radiol 28:4561–4569
Lung PFC et al (2018) Volume assessment magnetic resonance imaging technique for monitoring
perianal Crohn’s fistulas. Ther Adv Gastroenterol 11:1–8
Magnano G et al (2003) Polyethylene glycol and contrast-enhanced MRI of Crohn’s disease in
children: preliminary experience. Pediatr Radiol 33:385–391
Mahadev S, Young JM, Selby W, Solomon MJ (2011) Quality of life in perianal Crohn’s disease:
what do patients consider important? Dis Colon Rectum 54:579–585
Mahapatra D et al (2013) Automatic detection and segmentation of Crohn’s disease tissues from
abdominal MRI. IEEE Trans Med Imaging 32:2332–2347
Morris J, Spencer JA, Ambrose NS (2000) MR imaging classification of perianal fistulas and its
implications for patient management. Radiographics 20:623–635
13 Magnetic Resonance Imaging in the Diagnosis, Characterization, and.. . 211
Ng SC et al (2009) Prospective evaluation of anti-tumor necrosis factor therapy guided by magnetic
resonance imaging for Crohn’s perineal fistulas. Am J Gastroenterol 104:2973–2986
Parks AG, Gordon PH, Hardcastle JD (1976) A classification of fistula-in-ano. Br J Surg 63:1–12
Pikarsky AJ, Gervaz P, Wexner SD (2002) Perianal Crohn disease. Arch Surg 137:3–7
Present DH et al (1999) Infliximab for the treatment of fistulas in patients with Crohn’s disease.
N Engl J Med 340:1398–1405
Rincón M et al (2017) Improved automatic segmentation of white matter hyperintensities in MRI
based on multilevel lesion features. Neuroinformatics 15:231–245
Sahnan K et al (2018a) Improving the understanding of perianal Crohn fistula through 3D
modeling. Ann Surg 267:e105–e107
Sahnan K et al (2018b) Innovation in the imaging perianal fistula: a step towards personalised
medicine. Ther Adv Gastroenterol 11:1756284818775060
Sahnan K et al (2019a) Developing a core outcome set for fistulising perianal Crohn’s disease. Gut
68:226–238
Sahnan K et al (2019b) The use of 3D imaging to facilitate training during complex fistula surgery –
a video vignette. Color Dis 21:376
Sahni VA, Ahmad R, Burling D (2008) Which method is best for imaging of perianal fistula?
Abdom Imaging 33:26–30
Samaan MA et al (2017) The development of a magnetic resonance imaging index for fistulising
Crohn’s disease. Aliment Pharmacol Ther 46:516–528
Sands BE, Blank MA, Patel K, Van Deventer SJ (2004) Long-term treatment of rectovaginal fistulas
in Crohn’s disease: response to infliximab in the ACCENT II study. Clin Gastroenterol Hepatol
2:912–920
Scholefield JH, Berry DP, Armitage NC, Wastie ML (1997) Magnetic resonance imaging in the
management of fistula in ano. Int J Color Dis 12:276–279
Schwartz DA et al (2001) A comparison of endoscopic ultrasound, magnetic resonance imaging,
and exam under anesthesia for evaluation of Crohn’s perianal fistulas. Gastroenterology 121:
1064–1072
Schwartz DA et al (2002) The natural history of fistulizing Crohn’
Minnesota. Gastroenterology 122:875–880
Spencer JA et al (1998) Outcome after surgery for perianal fistula: predictive value of MR imaging.
Am J Roentgenol 171:403–406
Tang ST et al (2009) Clinical value of pelvic 3-dimensional magnetic resonance image reconstruc-
tion in anorectal malformations. J Pediatr Surg 44:2369–2374
Tarrant KM, Barclay ML, Frampton CMA, Gearry RB (2008) Perianal disease predicts changes in
Crohn’s disease phenotype-results of a population-based study of inflammatory bowel disease
phenotype. Am J Gastroenterol 103:3082–3093
Tozer PJ, Burling D, Gupta A, Phillips RKS, Hart AL (2011) Review article: medical, surgical and
radiological management of perianal Crohn’s fistulas. Aliment Pharmacol Ther 33:5–22
Tozer P et al (2012) Long-term MRI-guided combined anti-TNF-α and thiopurine therapy for
Crohn’s perianal fistulas. Inflamm Bowel Dis 18:1825–1834
Van Assche G et al (2003) Magnetic resonance imaging of the effects of infliximab on perianal
fistulizing Crohn’s disease. Am J Gastroenterol 98:332–339
van Rijn KL et al (2020) Evaluation of the modified Van Assche index for assessing response to
anti-TNF therapy with MRI in perianal fistulizing Crohn’s disease. Clin Imaging 59:179–187
Villa C et al (2012) Role of magnetic resonance imaging in evaluation of the activity of perianal
Crohn’s disease. Eur J Radiol 81:616–622
Wake N, Wysock JS, Bjurlin MA, Chandarana H, Huang WC (2019) “Pin the tumor on the kidney:”
an evaluation of how surgeons translate CT and MRI data to 3D models. Urology 131:255–261
Zeng C, Xing W, Wu Z, Huang H, Huang W (2016) A combination of three-dimensional printing
and computer-assisted virtual surgical procedure for preoperative planning of acetabular fracture
reduction. Injury 47:2223–2227
s disease in Olmsted County,
Future Perspectives in the Diagnosis of Anal Fistula and Abscess
Sthela Murad-Regadas and Francisco Sergio P. Regadas Filho
Contents
1 Introduction . ............... .................................................................. 214
2 Assessment of Abscess and Anal Fistula ... . . . ....... . . . . ...... . . . . ....... . . . ....... . . . . ... 214
3 Abscess .......................... ............................................. ............... 216
3.1 Computed Tomography (CT) . . . . ....... . . . . ....... . . . . ...... . . . . . ...... . . . . ....... . . . 216
3.2 Magnetic Resonance Imaging (MRI) ........................................ ......... 216
3.3 Endoanal Ultrasound ... . . . ...... . . . . ...... . . . . .... . . . . . ...... . . . . ...... . . . ...... . . . . .. 216
3.4 Transperineal Ultrasonography (TP-US) ............................................. 217
4 Anal Fistula ....... ........................................................................... 217
4.1 Imaging . ............................................................................ ... 221
5 Conclusion ................................................................................... 229
6 Cross-References .......................... ............................................. ..... 229
References ............................ ............................................... ............ 229
14
Abstract
This chapter demonstrates the usefulness and reliability of images in the assessment of the anal fistula and abscess. We will discuss and emphasize the preoperative assessment as a significant role in the choice of the operative technique,
and consequently, in the prevention of complications like disease recurrence and
anal sphincter incontinence. Besides the symptoms and physical examination, it
is mandatory to view the entire extension of the fistulous tract and its relation to
the sphincter muscles and the exact position of the internal opening concerning
the anal margin and any secondary tracts and/or cavities as well as classify the
anal fistula as well as the percentage of sphincter muscle involved by the tract and
to be sectioned during surgery. So, optimally balancing benefits, we can choose
the possible and best modality of assessment for each patient.
S. Murad-Regadas (*) · F. S. P. Regadas Filho
School of Medicine, Federal University of Ceara, Fortaleza, Ceará, Brazil
e-mail: smregadas@hospitalsaocarlos.com.br
© Springer Nature Switzerland AG 2022
C. Ratto et al. (eds.), Anal Fistula and Abscess, Coloproctology,
https://doi.org/10.1007/978-3-030-76670-2_16
213
214 S. Murad-Regadas and F. S. P. Regadas Filho
Keywords
Ultrasound · Magnetic resonance image · Anal fistula · Abscess · Image
1 Introduction
Anal fistula and abscess remain challenging and require specialist expertise to an
adequate management. Anorectal abscesses are defined by the anatomic space where
it is located and classified according to its position, as perianal, ischiorectal,
intersphincteric, supralevator, and submucosal. An anal fistula is an abnorm al
connection between two epithelized surfaces that connects the perineal skin to the
anal canal and/or rectum. So, there are components that should be identified to
characterize the type of an anal fistula, as primary, secondary, or primary with a
secondary opening and adjacent cavity. It is classified according to tract directions
and its relationship with the anal sphincter muscles. Overall, in 80% of the cases, the
anal fistulas are cryptogenic and concomitant with a tract draining abscesses arising
from infected anal glands (Parks 1961; Tabry and Farrands 2011). However, fistulae
can also be due to Crohn’s disease, trauma, tuberculosis, hidradenitis suppurativa,
immunosuppression (including human immunodeficiency virus – HIV), lymphogranuloma venereum, sacrococcygeal teratoma, recta l duplication, and perianal
actinomycosis (Schwartz et al. 2002; Davis and Kasten 2019).
2 Assessment of Abscess and Anal Fistula
To successfully manage an abscess and fistula, it is essential to accurately understand
the anal canal and rectal anatomy as well as the perineal spaces and identify the
primary and secondary tract(s), course of its extension, and especially the relationship with the sphincter muscles. Understanding the anal anatomy, the distribution of
the muscles, and conformation of the anal canal is the key to choose the best
treatment option (Williams et al. 2001; Bollard et al. 2002; Regadas et al. 2007).
In a previous study using the 3D anorectal ultrasonography, it was demonstrated the
asymmetrical conformation of the anal canal according with the circumferential
distribution of the sphincter muscles and gender (Regadas et al. 2007). The anterior
part of the external anal sphincter (EAS) is the shortest muscle, and it is positioned
more distally concerning the posterior and lateral EAS/PR muscle position in both
men and women (Fig. 1). Furthermore, in the anterior quadrant, the muscles (especially the anterior EAS) are shorter, and the gap (area without external anal sphincter) is longer in women than in men, resulting in a weak area which explains the
higher incidence of pelvic floor dysfunction in women (Regadas et al. 2007) (Fig. 2).
The development of the three-dimensional (3D) anorectal ultrasonography (Gold
et al. 1999; Williams et al. 2001; Bollard et al. 2002; Regadas et al. 2007) and
magnetic resonance imaging excluded Morren et al; Hsu et al (Morren et al. 2001;
Hsu et al. 2005) to assess anal canal and pelvic floor anatomy (Morren et al. 2001;
14 Future Perspectives in the Diagnosis of Anal Fistula and Abscess 215
Fig. 1 Anatomic configuration of anal canal (sagittal plane). Female distribution of the sphincter
muscles. IAS, internal anal sphincter; EAS, external anal sphincter; gap area without external anal
sphincter; PR, puborectalis muscle
Fig. 2 Anatomic configuration of the anal canal, comparing female (a) with male (b) (sagittal
plane). IAS, internal anal sphincter; EAS, external anal sphincter; gap area without external anal
sphincter; PR, puborectalis muscle
216 S. Murad-Regadas and F. S. P. Regadas Filho
Hsu et al. 2005) has opened new possibilities for research, identifying clearly the
anal canal anatomy and becoming the best modality of diagnosis and established
method for pretreatment assessment of benign and malignant diseases of the anal
canal and rectum.
3 Abscess
Patients with an anorectal abscess complain of acute pain in the perianal or perirectal
area. Furthermore, frequently preclude an adequate rectal exam and a correct diagnostic, especially in patients with an intersphincteric or supralevator abscess. So, imaging
modalitiesmust be required to successfullyidentify complex abscess, providing cavity
position and the relation with the anal sphincters in order to choose the best technical
option for drainage such as an internal or using multiple counter incisions.
The imaging options to assess the size and cavity location can be done by
computed tomography (CT), magnetic resonance imaging (MRI), as well as ultrasound, especially the 3D modality, according to the availability of the method as well
as the examiner expertise since an inadequate drainage has been identified as a risk
factor for recurrent anorectal abscess (Davis and Kasten 2019).
3.1 Computed Tomography (CT)
This imaging exam can be indicated in any patient with an unclear anorectal abscess
diagnostic, such as complex suppurativ e anorectal conditions and patients with
comorbidities in which delay in diagnosis will be harmful.
Studies with multiplane reconstruction CT scans have proven to be useful in
evaluating anorectal abscess, demonstrating sensitivity rate of 77% and 70% in
immunocompetent and immunocompromised patients with confirmed anorectal
abscess (Caliste et al. 2011; Ortega et al. 2015, 2017).
3.2 Magnetic Resonance Imaging (MRI)
MRI is well indicated for the assessment of complex disease or p atients with
recurrent of incompletely drained abscess to identify horseshoe/postanal, supralevator, or other complex abscesses.
Studies have described the usefulness of MRI in the diagnostic and management
of supralevator abscess regarding its origin, location, and drainage route.
3.3 Endoanal Ultrasound
It’s performed by colorectal surgeons, even in the operation room if necessary.
Endoanal ultrasound is useful to show the location, the extension of the abscess
14 Future Perspectives in the Diagnosis of Anal Fistula and Abscess 217
cavity (with gas, liquid, or debris), and the relation with the sphincter muscles and
the rectal wall, making possible its classification, especially using the 3D modality.
The 3D modality is performed with 360
rotating anorectal transducer, high frequency (16 MHz), the focal distance between 2.8 and 6.2 cm, and automatic image
acquisition without manual movement of the transducer. Images up to 6.0 cm long
are captured along the proximal-distal axis for up to 55 s by moving two crystals on
the extremity of the transducer. The images are acquired as a series of transaxial
microsections up to 0.20 mm thick, producing consequently a high-resolution digitalized volumetric image (cube). The 3D volume can be saved, exported, reviewed, and
manipulated, visualizing the lesions at different angles and in different planes.
The ultrasound image is also able to show early inflammatory processes or the
late absorption stage, and these findings cannot be identified by proctological exam
alone and are not able to determine if the therapy should be conservative or surgical
and likewise useful to determine the location and extension of large abscesses
concerning the sphin cter muscles as well as in the choice of drainage location
(Figs. 3 and 4). Despite requiring instrumentation of the anus, the 3D modality is
also well-tolerated because the scanning procedure is quick and images may be
analyzed posteriorly as well as performed in the operating room (Murad-Regadas
and Regadas 2008) (Figs. 5 and 6).
3.4 Transperineal Ultrasonography (TP-US)
It is an option that can be entirely accurate in the diagnosis of the fluid collections,
internal opening, and even the existence and course of a fistulous tract. However, it
should be performed by an expert with experienced hands. It distinguishes perianal
from perirectal abscess and sepsis.
Previous studies mentioned that TP-US is useful for visualizing a perianal fistula
or abscess, and it is a simple and accurate diagnostic method and could be used for
the preliminary assessment and follow-up of perianal Crohn’s disease (Maconi et al.
2007, 2013).
4 Anal Fistula
Besides the symptoms and physical examination, factors should be considered in the
management of the anal fistula, as patients with pre-existing incontinence symptoms,
previous surgery with the division of sphincter (fistulotomy or sphincterotomy),
previous obstetric injury, and a tract in the anterior position, especially in female.
Physical exam findings may identify an opening on the anal margin, and the
palpation of the anal canal can frequently determine the location of the internal
opening. Howev er, it is mandatory to classify the anal fistula as well as calculate the
percentage of sphincter muscles involved by the tract and the risk of potential
damage to the anal sphincters . Besides, some factors classify the anal fistulas as
complex or simple. Complex fistulas include one of the following findings: more
218 S. Murad-Regadas and F. S. P. Regadas Filho
Fig. 3 (a–c) Female patient. Anterior intersphincteric abscess (with liquid) that drained into the
internalopening(IO) located at 1–2o’clock. (a) Axial plane: low anal canal. (b) Axial plane: mid-anal
canal. (c) Midsagittal plane: intersphincteric cavity at the level of the lower and mid-anal canal that
drainedinto the IO. IAS, internalanalsphincter; EAS, external anal sphincter; PR, puborectalis muscle
than >30% of the external anal sphincter involvement, suprasphincteric and extrasphincteric fistulas, horseshoe configuration, anterior location in female, presence of
multiple tracts, recurrent Crohn’s disease associated, prior radiotherapy, or baseline
incontinence. Simple is usually defined as intersphincteric or low transsphincteric
fistulas (<30% of EAS involvement) (Steele et al. 2011).
14 Future Perspectives in the Diagnosis of Anal Fistula and Abscess 219
Fig. 4 (a–c) Male patient. Posterior intersphincteric small cavity that drained into the internal
opening (IO) located at 6–7o’clock and a transsphincteric tract that crossed the internal anal
external anal sphincter at the level of the mid-anal canal. (a) Axial plane: mid-anal canal. Small
cavity that drained to the internal opening (IO) located at 6–7o’clock. (b) Axial plane: mid-anal
canal. (c) Midsagittal plane: cavity, internal opening (IO) and a transsphincteric tract. IAS, internal
anal sphincter; EAS, external anal sphincter; PR, puborectalis muscle
Furthermore, improper characterization of the type of fistula could lead to anal
sphincter injury, whereas the lack of identification of an internal opening and
extension could result in fistula recurrence, requiring subsequent surgery and
consequently increasing the risk of postoperative incontinence. The surgical procedure for anal fistula treatment is a significant reason for continence disorders due
to surgical trauma, as the division of considerable parts of the sphincter musculature. The high rates (18–64%) of continence disorders reported following the lay
open method of the anal fistula can be due to the heterogeneity of cases involved
and previous operations (Garcia-Aguilar et al. 1996; Zimmerman et al. 2001;