ERUS can be used to stage rectal tumors by assessing tumor depth (T staging), nodal status (N staging), and distance to circumferential resection margins. It has high sensitivity and specificity for T1-3 staging but is less accurate for T4 tumors and nodal metastases. ERUS is useful for evaluating submucosal invasion depth and predicting tumors amenable to endoscopic resection. Limitations include difficulty distinguishing post-treatment changes from residual tumor. ERUS provides complementary information to MRI for locoregional staging of rectal cancers.

1. Samir Haffar, M.D.
Endorectal ultrasound in rectal diseases

2. "It is necessary to see before reflecting,
to seize appearances before probing the causes;
and our ideas on any external object are vague
if they are not for us so many images.”
Xavier Bichat (1771 - 1802)
French anatomist and physiologist
Father of modern histology and
descriptive anatomy

3. (1) Normal ultrasound-anatomy of the rectum
(2) Endorectal ultrasound (ERUS) in rectal diseases
Rectal tumors
Submucosal lesions
Endorectal ultrasound for anorectal lesions

4. (1) Normal ultrasound-anatomy of the rectum

5. Santoro JA & Di Falco G. Endosonographic anatomy of the normal anal canal.
In: Santoro JA & Di Falco G (eds), Benign anorectal diseases. Springer-Verlag, Italia, 2006.
Coronal anatomy of the anal canal

6. Patient preparation
• Patients given routine enema two hours before examination
• Sedation not necessary
• Examination in left lateral decubitus, in knee-chest position
• Digital rectal exam before insertion of the probe into rectum:
Identify lesion size, location, & mobility of the tumor
Kim MJ. Ultrasonography 2015; 34:19-31.

7. Santoro GA. Recents advances in colorectal polyps. Genoa, 11 April 2014.
Good visualization depends on
Maintain probe in center of lumen
Distension of water-filled balloon
Good contact with rectal wall
Five layers of the rectal wall
2 - 3 mm thick

8. Normal blood vessels in the rectal wall
Axial ERUS image
Continuity of hypoechoic vessels more than cross-sectional diameter
is criterion used to distinguish vessels from hypoechoic lymph nodes
Blood vessels appear to branch or extend longitudinally
Santoro GA & Di Falco G. Stage uN1: Lymph node metastases.
In: Santoro GA & Di Falco G (eds), Atlas of endoanal & endorectal US. Springer, Italia, 2004.

9. Axial ERUS image Axial ERUS image
Santoro JA & Di Falco G. Endosonographic anatomy of the normal anal canal.
In: Santoro JA & Di Falco G (eds), Benign anorectal diseases. Springer-Verlag, Italia, 2006.
Normal peri-rectal US anatomy in males
Seminal vesicles Prostate

10. Uterus
Axial ERUS image
Vagina1
Ovary
Uterus
Bladder
Axial ERUS image
Uterus, ovary & bladder2
(1) Santoro JA & Di Falco G. Endosonographic anatomy of the normal anal canal.
In: Santoro JA & Di Falco G (eds), Benign anorectal diseases. Springer-Verlag, Italia, 2006.
(2) Roseau G. World J Gastrointest Endosc 2014; 6(11): 525-533.
Normal peri-rectal US anatomy in females

11. Iliac vessels
Long tubular anechoic structure near recto-sigmoid junction
Iliac region is important for nodal staging
Cooper ST & Sanders MK. Radial endoscopic ultaround.
In: Shami VM & Kahaleh M (eds), Endoscpic ultrasound. Springer, New York, 2010.

12. (2) Endorectal ultrasound in rectal diseases

13. Rectal tumors

14. • Tumor depth T staging
• Nodal metastasis N staging
• Circumferential resection margin Prostate & seminal vesicules
Vagina & uterus
Mesorectal fascia (MRF)
Loco-regional staging of rectal
adenoma/adenocarcinoma

15. Make every effort to image all 5 layers at all points of tumor because
tumor infiltration can differ significantly along the body of the tumor
uT staging in rectal cancer
uTx Primary tumor cannot be assessed
uT0 Noninvasive lesion confined to mucosa
uT1 Tumor confined to mucosa & submucosa
uT2 Tumor penetrates into but not through MP
uT3 Tumor extends into perirectal fat
uT4 Tumor involves adjacent structure
Berton F et al. AJR 2008; 190:1495–1504.

16. uT0 rectal lesion
Lesion expands inner hypoechoic (mucosa)
surrounded by uniform middle hyperechoic layer
Axial ERUS image

17. Santoro GA & Di Falco G. Endoluminal ultrasound in preoperative staging of rectal carcinoma.
In: Santoro GA et al (eds), Atlas of endoanal & endorectal ultrasonography. Springer, Italia, 2004.
uT1 rectal lesion
Diaphragmatic representation of T1
rectal tumor invading submucosa
Diaphragmatic representation
Tumor extended to hyperechoic
submucosa layer surrounded by
uniform hypoechoic muscularis layer
Axial ERUS image

18. Submucosal invasion of rectal cancer
Kudo differentiate 3 types of early invasive cancers
• SM-1 tumor: invading superior third of submucosa
• SM-2 tumor: invading superficial two thirds of submucosa
• SM-3 tumor: invading deep third of submucosa
Kudo S. Endoscopy 1993; 25: 455-461.

19. Increased rate of lymph node metastasis with increased
submucosal invasion
Kudo's classification

20. uT2 rectal lesion
Diaphragmatic representation of T2
rectal tumor invading muscolaris propria
Invasion of muscularis propria
based on its thickness
Intact perirectal fat interface
Diaphragmatic representation Axial ERUS image
Santoro GA & Di Falco G. Endoluminal ultrasound in preoperative staging of rectal carcinoma.
In: Santoro GA et al (eds), Atlas of endoanal & endorectal ultrasonography. Springer, Italia, 2004.

21. uT3 rectal lesion
T3 rectal tumor infiltrating
into peri-rectal fat
Diaphragmatic representation
Perirectal fat invasion based on
irregularities of outer hyperechoic layer
Axial ERUS image
Santoro GA & Di Falco G. Endoluminal ultrasound in preoperative staging of rectal carcinoma.
In: Santoro GA et al (eds), Atlas of endoanal & endorectal ultrasonography. Springer, Italia, 2004.

22. uT4 rectal lesion / Invasion of the prostate
Axial ERUS image2
Tumor invading into the
prostate anteriorly (arrow)
(1) Santoro GA & al. Endoluminal ultrasound in preoperative staging of rectal carcinoma.
In: Santoro GA et al (eds), Atlas of endoanal & endorectal ultrasonography. Springer, Italia, 2004.
(2) Chern H et al. Clinical Staging. In: Czito BG et al, Rectal cancer. Springer, New York, 2010.
Diaphragmatic representation1
Tumor involves adjacent structure

23. uT4 rectal lesion / Invasion of seminal vesicule
Intact seminal vesicula
Fatty tissue plane between tumor (Tm)
& right seminal vesicule (S)
Axial ERUS image Axial ERUS image
Same patient at another plane
Invasion of left seminal vesicule
Tm: tumor – S: seminal vesicule
Engin G. J Ultrasound Med 2006; 25:57–73.

24. Residual strictured lumen represented by small amount of echogenic air
Wall thickened & hypoechoic with no residual normal wall layers
Invasion of perirectal fat (T3 lesion)
Berton F et al. AJR 2008; 190:1495–1504.
ERUS in stenotic rectal lesion
less accuracy for T staging of stenotic tumors
Axial ERUS image

25. T staging of rectal cancer by ERUS
Meta-analysis and systematic review
ERUS should be strongly considered for T staging of rectal tumors
3630 references, 42 studies, N = 5039 pts
• T1: sensitivity 87.8% specificity 98.3%
• T2: sensitivity 80.5% specificity 95.6% - least accurately assessed
• T3: sensitivity 96.4% specificity 90.6%
• T4: sensitivity 95.4% specificity 98.3%
Puli Sr et al. Ann Surg Oncol 2009;16:254-6.

26. Can ERUS predict early rectal cancers that can
be resected endoscopically?
Meta-analysis & systematic review
• Data collection: Medline and PubMed
• 11 studies (N= 1791)
• TRUS for T0: 97.3% sensitivity 96.3% specificity
ERUS helps physicians accurately stage T0 rectal
cancers & offer endoscopic treatment to these patients
Puli SR et al. Dig Dis Sci 2010;55:1221-9.

27. N staging in rectal cancer (N)
• Nx: Regional lymph nodes cannot be assessed
• N0: No regional lymph nodes
• N1: Metastasis in 1 to 3 pericolic or perirectal LNs
• N2: Metastasis in 4 or more pericolic or perirectal LNs

28. uN+: lymph node metastasis
• Node diameter > 5 mm
• Hypoechoic or echogenicity similar to the primary tumor
• Lack of echogenic central area
• Circular rather than oval
• Discrete borders
• Adjacent or proximal to the tumor

29. Lymph node metastasis
Several rounded hypoechoic lymph nodes in mesorectal fascia (arrows)
Intact seminal vesicules anteriorly
Gollub MJ et al. Radiol Clin N Am 2007; 45: 85–118.

30. ERUS accuracy for nodal invasion in rectal cancer
Meta-analysis and systematic review
• 3610 references, 35 studies, N= 2732 pts
• N+: sensitivity 73.2% specificity 75.8%
• Criteria are needed to improve the diagnostic accuracy
Puli Sr et al. Ann Surg Oncol 2009;16:1255-65.

31. Circumferential resection margin in rectal cancer
• Seminal vesicles, prostate, and vagina
EUS can identify circumferential resection margin
• Mesorectal fascia (MRF)
MRI has better performance for assessment of MRF
One study reported strong correlation between 3D-ERUS & MRI2
(1) Kim MJ. Ultrasonography 2015;34:19-31.
(2) Phang PT et al. Dis Colon Rectum 2012;55:59-64.

32. The most powerful predictor for local recurrence is the shortest
distance from the tumor to the mesorectal fascia
T3* poses a higher risk for recurrence than T3△
Kim MJ. J Korean Med Assoc 2009; 52(5): 509 – 517.
Mesorectal fascia & rectal cancer

33. T2-weighted axial MRI1
MRF in healthy
subject (white arrows)
T3 rectal cancer (black arrow)
invading mesorectal fat
Intact MRF (white arrows)
T2-weighted MRI1
T3 rectal cancer (arrow
MRF involvement
(arrowheads)
T2-weighted MRI2
(1) Kim MJ. J Korean Med Assoc 2009; 52(5): 509 – 517.
(2) Heo SH et al. World J Gastroenterol 2014; 20(15): 4244-4255.
Mesorectal fascia (MRF)

34. Misinterpretation of ERUS in rectal cancer
• Close proximity to anal verge
• Improper balloon inflation
• Artifact from air or stool
• Refraction artifact
• Post-biopsy or surgical change
• Hemorrhage
• Pedunculated tumor
Marone P et al. World J Gastrointest Endosc 2015; 7(7): 688-701.

35. Overstaging in rectal cancer
Hemorrhage in biopsy area
Axial ERUS after endoscopic biopsy
T1 overstaging adenocarcinoma
Mass confined with adventitial layer (arrows) at 6-o’clock
Overstaging of T1 tumor caused by hemorrhage in biopsy area
Engin G. J Ultrasound Med 2006; 25:57–73.

36. Thickening of submucosal layer at 9-o’clock
Appearance of T1 rectal tumor confined to submucosa (arrows)
Normal examination when repeated after negative endoscopy results
False-positive finding due to a sharp bend in the rectum
Engin G. J Ultrasound Med 2006; 25:57–73.
Axial ERUS image
False positive diagnosis of rectal tumor

37. MRI ERUS
Availability Radiology department Office
Patient contraindications Metal implants, claustrophobia None
Anatomic location Good Excellent
Tissue resolution Excellent Good
Anatomic coverage Wide Narrow
Operator dependency High Very high
Early cancer T1 vs. T2 Poor Good
T1/T2 vs. T3 Good Good
T4 Excellent Only ant tumors
Mesorectal nodes Moderate Moderate
Internal Iliac/sup rectal nodes Good Poor
Relationship to mesorectal fascia Excellent Poor
Infiltration of levator muscle Good Moderate
Infiltration of anal sphincter Moderate Good
Kim MJ. Ultrasonography 2015;34:19-31.
MRI & ERUS in rectal tumors

38. ERUS and MRI play a complementary role in
the loco-regional staging of rectal tumors

39. ERUS
uT0 uT1-T2 N0 uT3-T4 &/or N+
Surgery MRI
Chemoradiation
Endoscopic resection
Therapeutic strategy in rectal cancer

40. sub-mucosa
scar tissue
ERUS following endoscopic excision
ERUS two months after endoscopic excision
Focal widening of hypoechoic layer (muscolaris mucosa)
Disruption of hyperechoic layer (submucosa)
Changes consistent with post-fulguration scar tissue
Santoro GA & Di Falco G. Postsurgical evaluation.
In: Santoro GA et al (eds), Atlas of endoanal & endorectal ultrasonography. Springer, Italia, 2004.

41. site of excision
submucosa
Hypoechoic lesion in muscolaris propria of 1.5 cm adjacent to prostate
Intact peri-rectal fat interface (T2)
No residual tumor was identified at histopathologic analysis
Rectal wall scarring misinterpreted as T2 lesion
Santoro GA & Di Falco G. Postsurgical evaluation.
In: Santoro GA et al (eds), Atlas of endoanal & endorectal ultrasonography. Springer, Italia, 2004.
ERUS three months after endoscopic excision
ERUS following endoscopic excision

42. ERUS after neo-adjuvant therapy (NAT)
Low accuracy in restaging rectal cancer
Difficulty to differentiate inflammation & fibrosis from
actual residual cancer
Marone P et al. World J Gastrointest Endosc 2015; 7(7): 688-701.

43. Effect of radiation on rectal wall
The rectal wall is thickened, more hypoechoic, and hypervascularized
Different layers less clearly visualized
Santoro GA & Di Falco G. Staging following preoperative chemoradiotherapy for rectal cancer.
In: Santoro GA et al (eds), Atlas of endoanal & endorectal ultrasonography. Springer, Italia, 2004.
perirectal fat
blood vessel
submucosa

44. ERUS following neoadjuvant chemoradiation
perirectal fat
MP
sub-mucosa
perirectal
fat
residual
tumor ?
Irregular peri-rectal fat interface
3 hypoechoic LNs (arrows)
EUS staging: uT3N1
Probable tumor in left anterolateral wall
Regular peri-rectal fat interface
EUS restaging: uT2N0
Pathologic staging: pT0N0
ERUS before chemoradiation ERUS following chemoradiation
Santoro GA & Di Falco G. Staging following preoperative chemoradiotherapy for rectal cancer.
In: Santoro GA et al (eds), Atlas of endoanal & endorectal ultrasonography. Springer, Italia, 2004.

45. ERUS following surgical treatment
• ERUS has high sensitivity but low specificity in local recurrences
Inability to differentiate postoperative changes & benign lesion
from recurrence
• EUS-FNA increases specificity but there are no clear data that
it influence patients survival after surgery for rectal cancer
Marone P et al. World J Gastrointest Endosc 2015; 7(7): 688-701.

46. ERUS of a stapled anastomosis
Clips
Suturing clips visible as bright spots with dorsal shadow
Typical structure of rectal wall interrupted by the anastomosis
presenting as ring with hyperechoic thick inner layer
followed by small echo poor layer
surrounded by small white interface layer (perirectal fat interface)
Santoro GA & Di Falco G. Postsurgical evaluation.
In: Santoro GA et al (eds), Atlas of endoanal & endorectal ultrasonography. Springer, Italia, 2004.

47. Recurrent posterior extraluminal rectal carcinoma at site of resection
appearing like 4 x 4 cm mixed echogenicity rounded mass
Santoro GA & Di Falco G. Local recurrences.
In: Santoro GA et al (eds), Atlas of endoanal & endorectal ultrasonography. Springer, Italia, 2004.
ERUS following surgical resection

48. • 3D-US Better T & N staging compared to 2D-ERUS & CT scan
Correct visualization of mesorectal fascia (MRF)
• CDUS Quantifying tumor angiogenesis with prognostic information
• CEUS Limited information on its role in rectal cancer
Quantifying tumour angiogenesis (anti-angiogenic therapy)
Differentiate benig/malignant LN (correct use of EUS-FNA)
• Elastography May differentiate benign from malignant lesions
NAT: neoadjuvent therapy - CDUS: color Doppler US - CEUS: contrast enhanced ultrasound
Marone P et al. World J Gastrointest Endosc 2015; 7(7): 688-701.
Future perspectives of ERUS in rectal cancer

49. Probe creates parallel axial images packaged to create a 3D volume
Shobeiri SA. 2D/3D endovaginal & endoanal instrumentation and techniques.
In Shobeiri SA (Ed), Practical pelvic floor ultrasonography, Springer, New York, 2014.
3-D endorectal ultrasound

50. Miro AGF et al. SA. Preoperative staging of rectal cancer: role of endorectal ultrasound.
In Giulio A. Santoro (Eds), Rectal cancer - A multidisciplinary approach to management,
Intech, 2011.
uN+ on 3-D endorectal ultrasound

51. 3-D ERUS in loco-regional staging of rectal cancer
Recently published data show excellent results for T & N staging
• T staging: T1 tumor 97%
T2 tumor 94%
T3 tumor 96%
T4 tumor 98.5%
• N staging: diagnostic accuracy 87%
Compensate for some limitations imposed by ERUS
Kolev NY et al. Int Surg 2014; 99: 106-111.

52. Typical hypervascularity
Color demarcates tumor from
normal rectal wall on left side
Technique helpful for tumor staging
Hypoechoic tumor
Destruction of submucosa & involvement
of muscularis propria on right side
Berton F et al. AJR 2008; 190:1495–1504.
Color Doppler in rectal cancer
58-year-old man with T2 rectal cancer
Axial ERUS image Color Doppler ERUS image

53. Contrast-enhanced US
B mode image
T3 rectal lesion
Contrast harmonic image
before contrast injection
Hyperenhanced areas alternating
with avascular (necrotic) areas
Contrast harmonic image
15s after contrast injectio
Cârțână ET et al. World J Gastroenterol 2016; 22(5): 1756-1766.

54. Principle of elastography
may allow differentiation of benign from malignant lesions
• Adding color overlay coding for different elasticity values
Red color: soft tissue
Blue color: hard tissue
• Tissue strain: calculated by integrated software application
Strain ratio reports elasticity of selected normal tissue to target lesion
Strain ratio cut-off value of 1.25 differentiate adenoma/adenocarcinoma
Cârțână ET et al. World J Gastroenterol 2016; 22(5): 1756-1766.

55. Normal appearance of anal canal in elastography
IAS consisted of softer areas than the EAS, appears in red color
EAS consisted of harder elements than the IAS appears in blue
Albuquerque A. World J Gastrointest Endosc 2015; 7(6): 575-581.

56. Elastography in rectal adenoma
Rectal tumor from 2 to 7 o’clock position
Difficult to determine adenoma from early adenocarcinoma
Mucosal layer not clearly distinguished from submocosal layer
Real-time Elastogram
Tumor appears softer (more red)
than same-depth reference tissue
US image with strain ratio
Strain ratio = 0.54 (indicate adenoma)
Confirmed on resection specimen
Waage JER et al. Colorectal Dis 2014; 17, 124–132.

57. Elastography in rectal adenocarcinoma
Adenocarcinoma situated from 11 to 3 o’clock
Elastogram
Tumor appears harder (more blue)
than same depth reference tissue
US image with strain ratio
Strain ratio = 5.56
Indicative of adenocarcinoma
Waage JER et al. Colorectal Dis 2014; 17, 124–132.

58. ERUS in loco-regional staging of rectal cancer
Summary
• Significant learning curve
• Highly operator dependent
• Accurate in determining depth of invasion (T staging)
• Moderately accurate in assessment of LN involvement (N staging)
• Inaccurate in assessment of mesorectal fascia (MRF)
• Excellent results of 3D-ERUS for T and N staging

59. Rectal lymphoma
64-year-old man with known lymphoma & GI involvement
Axial ERUS image of posterior rectal wall
Intact mucosa & submucosal layers which excludes adenocarcinoma
Extensive hypoechoic tumor involving deep layers of rectal wall
Diffuse extension into perirectal fat evident as many hypoechoic bands
Berton F et al. AJR 2008; 190:1495–1504.

60. Submucosal lesions

61. Rectal submucosal lesions
limited reports on use
• Broad spectrum of intramural lesions and extrinsic compressions
• Differential diagnosis based on originating wall layer & echostructure
• Cytological & histological confirmation by performing EUS-FNA
Cârțână ET et al. World J Gastroenterol 2016; 22(5): 1756-1766.

62. Rectal submucosal lesions
• Intramural lesions Gastrointestinal stromal tumor (GIST)
"broad spectrum" Leiomyoma
Neuroendocrine tumor (NET)
Lipoma
Lymphangioma
Granular cell tumor
Varices
Pneumatosis coli
Linitis plastica
Duplication cyst
Endometriosis
• Extramural compressions mimicking intramural lesions
De Parades V et al. Acta Endoscopica 2006; 36(1): 87-100.

63. Rectal gastrointestinal stromal tumor (GIST)
59-year-old woman – asymptomatic tumor at routine examination
Axial ERUS image
Solid well-defined round mass arising from muscularis propria
Tumor is growing with submucosal pattern
Mucosal surface bulges into fluid-filled lumen
Berton F et al. AJR 2008; 190:1495–1504.

64. Rectal neuroendocrine tumor (NET)
81 year-old male patient underwent colonoscopy for
intermittent hematochezia
Sessile lesion in the distal
rectum measuring 15 mm
Endoscopic image
Hypoechoic lesion from the second layer
Biopsies: well differentiated NET
Axial ERUS image
www.grupuge.com.pt

65. Polyp mass with 0.9 cm central ulceration
Otherwise normal surface mucosa
Endoscopic image
Hyperechoic round lesion
at the submucosal layer
Axial ERUS
Lim CS et al. Endoscopy 2012; 44: E306–E307.
Rectal lipoma
53-year-old woman with a 3- month history of
intermittent hematochezia

66. Rectal varices
Endoscopic image
Color flow images of rectal varices
and inflowing vessel
Color Doppler ERUS
Sato T et al. Diagnosis and endoscopic treatments of rectal varices.
In: Da Rocha JR (ed), Endoscopic procedures in colon and rectum. InTech, 2011.

67. Pneumatosis coli
Multiple smooth submucosal lesions in
sigmoid about 20 cm from insertion site
Endoscopic image Axial EUS image
Air interface in the submucosa
with acoustic shadowing
http://www.healio.com/gastroenterology/news/blogs/

68. Linitis plastica of the rectum
secondary to another close or distant cancer but can also be primitive
Rectal linitis plastica by extension from vesical carcinoma
Circumferential hypoechogenic & heterogeneous thickness of rectal wall
Complete disorganization of the usual five layer structure
Deep biopsies are often negative
Similar appearance in radiation proctitis, IBD, & SURS
De Parades V et al. Acta Endoscopica 2006; 36(1): 87-100.

69. Subacute radiation proctitis
Nodular ulcerated mass (large arrow)
Telangiectasias typical of radiation
proctitis (small arrow)
Endoscopic image
Full wall thickness without mass
Thick mucosa (large white arrow)
Thick perirectal fat (small white arrow)
Prostate anterior to rectum (black arrow)
Axial ERUS
Williams G & Brian MY. J Ultrasound Med 2010; 29:1495–1498.

70. ERUS in inflammatory bowel disease
can differentiate active UC from active Crohn's disease
Total wall thickness
Thickened mucosal layer (bracket)
Patient with active UC
Total wall thickness
Thickened submucosal layer (bracket)
Patient with active Crohn’s disease
Ellrichmann M et al. Aliment Pharmacol Ther 2014; 39: 823–833.

71. Solitary rectal ulcer syndrome (SRUS)
24-year-old man – blood & mucus in stool for 6 months
Loss of first interface layer & muscularis mucosa
Thickening of submucosa & muscularis propria
Axial ERUS at 9 cm from the anal verge
Sharma M & Somasundaram A. Gastroenterology 2011;141:e7–e8.

72. Rectal duplication
Axial ERUS image
Rounded anechoic cystic lesion in the retrorectal region
Hypoechoic layer in cystic wall strongly suggestive
but atypical forms are frequent
Transformation is a rare but concerning complication
Case courtesy of Dr Maulik S Patel, Radiopaedia.org, rID: 25874

73. Epidermoid retrorectal (presacral cyst)
Axial ERUS image
Anechoic circular image in posterior middle & lower rectum
Epidermoid retrorectal/presacral cyst
dos Reis Lima DM et al. J Coloproctol (rio j) 2015;35(1):53–58.

74. Infiltrating endometriosis
• Endometriosis of digestive tract
Rectum & sigmoid are most frequent locations: 90% of cases
Hypoechoic thickening of MP from superficial to deep part
Sub-mucosae infiltration in advanced disease
Sensitivity 87-100% and specificity 66-100% in different series
• Other pelvic endometriosis locations
Ovary - torus uterinus - bladder - uterosacral ligament (USL)
ERUS can localize USL only when it is infiltrated by endometriosis
Roseau G. World J Gastrointest Endosc 2014; 16; 6(11): 525-533.

75. Classification of intestinal endometriosis
Rossini & Ribeiro
Classification of depth of intestinal infiltration
ueT1 Extra intestinal lesion
ueT2 Infiltrate serosa
ueT3 Infiltrates serosa & MP
ueT4 From serosa to submucosa
ueT5 From serosa to mucosa
MP: muscularis propria
Rossini LGB et al. Endoscopic Ultrasound 2012; 1(1): 23-35.

76. Classification of intestinal endometriosis
ERUS - Linear probe
ueT1
ueT2
ueT3
ueT5
ueT4
Rossini LGB et al. Endoscopic Ultrasound 2012; 1(1): 23-35.

77. Endometriosis
Heterogeneous lesion in the rectovaginal septum
Vieira AM et al. Rev Esp Enferm Dig (Madrid) 2010; 102(5): 308-313.
Axial ERUS image

78. Pelvic endometriosis locations
Infiltrated torus uterinus
Infiltrated utero-sacral ligament
Bilateral ovarian endometriomas
Bladder nodule
Roseau G. World J Gastrointest Endosc 2014; 16; 6(11): 525-533.

79. Accuracy of imaging modalities in endometriosis
• ERUS Accurate for recto-vaginal septum & recto-
sigmoid walls
• TVUS Accurate for endometriomas
• MRI Accurate for torus, uterosacral ligament &
small bladder lesion
TVUS: transvaginal ultrasound
Gauche Cazalis C et al. Gynecol Obstet Fertil 2012; 40: 634-641.

80. Thank You