DOI: 10.1148/rg.263055086
Preoperative Staging of Rectal Cancer with MR Imaging: Correlation with Surgical and Histopathologic Findings1
Franco Iafrate, MD,
Andrea Laghi, MD,
Pasquale Paolantonio, MD,
Marco Rengo, MD,
Paolo Mercantini, MD,
Mario Ferri, MD,
Vincenzo Ziparo, MD and
Roberto Passariello, MD
1 From the Department of Radiological Sciences, University of Rome "La Sapienza," Policlinico Umberto I, Viale Regina Elena 324, 00161 Rome, Italy (F.I., A.L., P.P., M.R., R.P.); and the Department of Surgery, University of Rome "La Sapienza," Azienda Ospedaliera Sant’ Andrea, U.O.C. Chirurgia A, Rome, Italy (P.M., M.F., V.Z.). Presented as an education exhibit at the 2004 RSNA Annual Meeting. Received April 11, 2005; revision requested June 10 and received August 8; accepted August 9. All authors have no financial relationships to disclose.
View larger version (160K):
[in a new window]
|
Figure 1. Rectal adenocarcinoma. Sagittal turbo spin-echo T2-weighted MR image obtained with a high-resolution phased-array surface coil shows a stenosing lesion (arrow) of the rectal lumen (*). This lesion is outside the potential field of view of endorectal US and endorectal coil MR imaging.
|
|
View larger version (192K):
[in a new window]
|
Figure 2. Coronal turbo spin-echo T2-weighted MR image shows the normal anatomy of the rectum. The white line indicates the lower limit of the rectum at the insertion of the levator ani muscle (arrows) on the rectal wall. The levator ani muscle forms the ceiling of the ischiorectal fossa.
|
|
View larger version (110K):
[in a new window]
|
Figure 3a. Normal anatomy of the mesorectum. (a) Axial turbo spin-echo T2-weighted MR image shows the mesorectal fascia as a thin, hypointense layer (white arrowheads) surrounding hyperintense mesorectal fat. On the anterior aspect, the mesorectal fascia appears more thickened and is difficult to differentiate from the Denonvillier fascia (black arrowheads). (b) Photograph of a section of the explanted rectum shows perirectal fat surrounded by the mesorectal fascia.
|
|
View larger version (86K):
[in a new window]
|
Figure 3b. Normal anatomy of the mesorectum. (a) Axial turbo spin-echo T2-weighted MR image shows the mesorectal fascia as a thin, hypointense layer (white arrowheads) surrounding hyperintense mesorectal fat. On the anterior aspect, the mesorectal fascia appears more thickened and is difficult to differentiate from the Denonvillier fascia (black arrowheads). (b) Photograph of a section of the explanted rectum shows perirectal fat surrounded by the mesorectal fascia.
|
|
View larger version (95K):
[in a new window]
|
Figure 4. Coronal turbo spin-echo T2-weighted MR image obtained with a phased-array surface coil shows a normal anal sphincter complex. The levator ani muscle (straight arrows) appears as a funnel-shaped muscular layer that extends from the obturator ani muscle to the anal canal. The puborectalis muscle (arrowheads) is depicted at the insertion of the levator ani muscle onto the anal canal. The external (curved arrows) and internal (*) sphincter muscles are also seen.
|
|
View larger version (187K):
[in a new window]
|
Figure 5. Rectal carcinoma. Coronal turbo spin-echo T2-weighted MR image shows a stage T1 tumor (*) of the rectum. The tumor has an intermediate signal intensity between the high signal intensity of the fat tissue (jagged line) and the low signal intensity of the muscular layer (black arrow). The inner layer of the rectal wall (white arrow) consists of mucosal and submucosal layers and has a high signal intensity.
|
|
View larger version (178K):
[in a new window]
|
Figure 6a. Stage T1 rectal carcinoma. (a) Coronal turbo spin-echo T2-weighted MR image shows a huge pedunculated tumor (T) on the left lateral rectal wall. The integrity of the muscular layer (arrow) appears not to be disrupted. The mesorectal fat (*) has a homogeneous appearance without tumoral involvement. The mesorectal fascia (arrowheads) is also well depicted. (b) Photomicrograph (original magnification, x4; hematoxylin-eosin [H-E] stain) shows neoplastic glands (arrow) disrupting the mucosal and submucosal layers of the rectal wall and the integrity of the muscular layer (*). A desmoplastic reaction (arrowhead) is visible near the neoplastic glands.
|
|
View larger version (186K):
[in a new window]
|
Figure 6b. Stage T1 rectal carcinoma. (a) Coronal turbo spin-echo T2-weighted MR image shows a huge pedunculated tumor (T) on the left lateral rectal wall. The integrity of the muscular layer (arrow) appears not to be disrupted. The mesorectal fat (*) has a homogeneous appearance without tumoral involvement. The mesorectal fascia (arrowheads) is also well depicted. (b) Photomicrograph (original magnification, x4; hematoxylin-eosin [H-E] stain) shows neoplastic glands (arrow) disrupting the mucosal and submucosal layers of the rectal wall and the integrity of the muscular layer (*). A desmoplastic reaction (arrowhead) is visible near the neoplastic glands.
|
|
View larger version (182K):
[in a new window]
|
Figure 7a. Stage T1 rectal carcinoma. (a) Axial turbo spin-echo T2-weighted MR image shows a polypoid tumor (T) on the right lateral aspect of the rectal wall protruding into the rectal lumen. It is difficult to determine whether the muscular layer (arrow), which appears thinned, is infiltrated or spared. (b) Coronal turbo spin-echo T2-weighted MR image shows the tumor (T) invading the rectal wall without infiltrating the perirectal fat (arrow). In this imaging plane, the distance of the tumor from the plane of the levator ani muscle (L) and from the anal sphincter complex (A) can easily be evaluated. (c) Photomicrograph (original magnification, x4; H-E stain) reveals multiple neoplastic glands (curved arrow) confined to the submucosal layer. The border between normal bowel mucosal glands (straight arrow) and the neoplastic glands is clearly visible (*). (d) Photomicrograph (original magnification, x4; H-E stain) shows that the integrity of the muscular layer (M) and the perirectal fat (*) has not been disrupted. The boundary between the muscular layer and fat tissue is evident (arrow).
|
|
View larger version (131K):
[in a new window]
|
Figure 7b. Stage T1 rectal carcinoma. (a) Axial turbo spin-echo T2-weighted MR image shows a polypoid tumor (T) on the right lateral aspect of the rectal wall protruding into the rectal lumen. It is difficult to determine whether the muscular layer (arrow), which appears thinned, is infiltrated or spared. (b) Coronal turbo spin-echo T2-weighted MR image shows the tumor (T) invading the rectal wall without infiltrating the perirectal fat (arrow). In this imaging plane, the distance of the tumor from the plane of the levator ani muscle (L) and from the anal sphincter complex (A) can easily be evaluated. (c) Photomicrograph (original magnification, x4; H-E stain) reveals multiple neoplastic glands (curved arrow) confined to the submucosal layer. The border between normal bowel mucosal glands (straight arrow) and the neoplastic glands is clearly visible (*). (d) Photomicrograph (original magnification, x4; H-E stain) shows that the integrity of the muscular layer (M) and the perirectal fat (*) has not been disrupted. The boundary between the muscular layer and fat tissue is evident (arrow).
|
|
View larger version (200K):
[in a new window]
|
Figure 7c. Stage T1 rectal carcinoma. (a) Axial turbo spin-echo T2-weighted MR image shows a polypoid tumor (T) on the right lateral aspect of the rectal wall protruding into the rectal lumen. It is difficult to determine whether the muscular layer (arrow), which appears thinned, is infiltrated or spared. (b) Coronal turbo spin-echo T2-weighted MR image shows the tumor (T) invading the rectal wall without infiltrating the perirectal fat (arrow). In this imaging plane, the distance of the tumor from the plane of the levator ani muscle (L) and from the anal sphincter complex (A) can easily be evaluated. (c) Photomicrograph (original magnification, x4; H-E stain) reveals multiple neoplastic glands (curved arrow) confined to the submucosal layer. The border between normal bowel mucosal glands (straight arrow) and the neoplastic glands is clearly visible (*). (d) Photomicrograph (original magnification, x4; H-E stain) shows that the integrity of the muscular layer (M) and the perirectal fat (*) has not been disrupted. The boundary between the muscular layer and fat tissue is evident (arrow).
|
|
View larger version (179K):
[in a new window]
|
Figure 7d. Stage T1 rectal carcinoma. (a) Axial turbo spin-echo T2-weighted MR image shows a polypoid tumor (T) on the right lateral aspect of the rectal wall protruding into the rectal lumen. It is difficult to determine whether the muscular layer (arrow), which appears thinned, is infiltrated or spared. (b) Coronal turbo spin-echo T2-weighted MR image shows the tumor (T) invading the rectal wall without infiltrating the perirectal fat (arrow). In this imaging plane, the distance of the tumor from the plane of the levator ani muscle (L) and from the anal sphincter complex (A) can easily be evaluated. (c) Photomicrograph (original magnification, x4; H-E stain) reveals multiple neoplastic glands (curved arrow) confined to the submucosal layer. The border between normal bowel mucosal glands (straight arrow) and the neoplastic glands is clearly visible (*). (d) Photomicrograph (original magnification, x4; H-E stain) shows that the integrity of the muscular layer (M) and the perirectal fat (*) has not been disrupted. The boundary between the muscular layer and fat tissue is evident (arrow).
|
|
View larger version (192K):
[in a new window]
|
Figure 8a. Stage T2 rectal carcinoma. (a) Coronal turbo spin-echo T2-weighted MR image shows a stenosing neoplastic lesion (*) of the rectal lumen involving the mucosal, submucosal, and muscular layers. The muscular layer is visible as a continuous hypointense line, and no neoplastic spread into the mesorectal fat (arrow) is seen. The major criterion for differentiating between stage T2 and stage T3 tumors is the presence of neoplastic tissue within the mesorectal fat. (b) Photomicrograph (original magnification, x4; H-E stain) shows complete infiltration of the muscular layer (M) by neoplastic glands (arrow).
|
|
View larger version (161K):
[in a new window]
|
Figure 8b. Stage T2 rectal carcinoma. (a) Coronal turbo spin-echo T2-weighted MR image shows a stenosing neoplastic lesion (*) of the rectal lumen involving the mucosal, submucosal, and muscular layers. The muscular layer is visible as a continuous hypointense line, and no neoplastic spread into the mesorectal fat (arrow) is seen. The major criterion for differentiating between stage T2 and stage T3 tumors is the presence of neoplastic tissue within the mesorectal fat. (b) Photomicrograph (original magnification, x4; H-E stain) shows complete infiltration of the muscular layer (M) by neoplastic glands (arrow).
|
|
View larger version (161K):
[in a new window]
|
Figure 9a. Stage T3 rectal carcinoma without involvement of the mesorectal fascia. (a) Axial turbo spin-echo T2-weighted MR image shows a neoplastic rectal lesion (arrow) disrupting the integrity of the muscular layer and invading the surrounding mesorectal fat. (b) Photomicrograph (original magnification, x4; H-E stain) shows neoplastic involvement of the perirectal fat (F). A necrotic area (white arrow) as well as arterial vessel (v) infiltration (black arrow) are evident. (c) Photograph of the gross specimen shows an ulcerated neoplastic lesion (arrow).
|
|
View larger version (178K):
[in a new window]
|
Figure 9b. Stage T3 rectal carcinoma without involvement of the mesorectal fascia. (a) Axial turbo spin-echo T2-weighted MR image shows a neoplastic rectal lesion (arrow) disrupting the integrity of the muscular layer and invading the surrounding mesorectal fat. (b) Photomicrograph (original magnification, x4; H-E stain) shows neoplastic involvement of the perirectal fat (F). A necrotic area (white arrow) as well as arterial vessel (v) infiltration (black arrow) are evident. (c) Photograph of the gross specimen shows an ulcerated neoplastic lesion (arrow).
|
|
View larger version (138K):
[in a new window]
|
Figure 9c. Stage T3 rectal carcinoma without involvement of the mesorectal fascia. (a) Axial turbo spin-echo T2-weighted MR image shows a neoplastic rectal lesion (arrow) disrupting the integrity of the muscular layer and invading the surrounding mesorectal fat. (b) Photomicrograph (original magnification, x4; H-E stain) shows neoplastic involvement of the perirectal fat (F). A necrotic area (white arrow) as well as arterial vessel (v) infiltration (black arrow) are evident. (c) Photograph of the gross specimen shows an ulcerated neoplastic lesion (arrow).
|
|
View larger version (181K):
[in a new window]
|
Figure 10. Stage T3 tumor with involvement of the mesorectal fascia. Coronal turbo spin-echo T2-weighted MR image shows a neoplastic rectal lesion infiltrating the mesorectal fat and involving the mesorectal fascia (arrowheads), which appears thickened. The mesorectal fascia represents the surgical resection margin. Patients with this kind of tumor benefit from preoperative neoadjuvant therapy to reduce the postoperative local recurrence rate.
|
|
View larger version (190K):
[in a new window]
|
Figure 11. Stage T4 tumor. Axial turbo spin-echo T2-weighted MR image shows a neoplastic rectal lesion (arrow) disrupting the mesorectal fascia. Tumoral infiltration of the seminal vesicles (*) is also evident.
|
|
View larger version (42K):
[in a new window]
|
Figure 12. Drawing illustrates the relationship between the CRM and rectal tumors of various stages (8). The local recurrence rate is strictly dependent upon CRM infiltration; thus, the most important predictor of local recurrence is a short tumor–mesorectal fascia distance (double-headed arrows). The actual T staging system does not differentiate between tumors with a wide CRM (T3 ) and those with a narrow CRM (T3*). Of these stage T3 tumors, the latter poses a higher risk for recurrence. At MR imaging, it is important to be able to identify patients with infiltrating tumors that have a narrow CRM or that infiltrate the mesorectal fascia who might benefit from neoadjuvant treatment. T1 = stage T1 tumor, T2 = stage T2 tumor, T4 = stage T4 tumor, Ves = vesicle.
|
|
View larger version (117K):
[in a new window]
|
Figure 13a. Stage T2 tumor with a peritumoral desmoplastic reaction. (a) Axial turbo spin-echo T2-weighted MR image shows a neoplastic lesion (*). The muscular layer is not recognizable, and neoplastic tissue seems to have spread into the mesorectal fat (arrowheads), a finding that represents one of the most frequent causes of overstaging. The perirectal fat stranding is actually due to a peritumoral desmoplastic reaction. (b) Photomicrograph (original magnification, x4; H-E stain) shows neoplastic glands (arrow) disrupting the muscular layer. A strong desmoplastic reaction (arrowheads) involving the fat tissue (FT) is also evident. (c) Photograph of a section of the explanted mesorectum shows the neoplastic lesion (*) and desmoplastic involvement of the perirectal fat (arrow).
|
|
View larger version (213K):
[in a new window]
|
Figure 13b. Stage T2 tumor with a peritumoral desmoplastic reaction. (a) Axial turbo spin-echo T2-weighted MR image shows a neoplastic lesion (*). The muscular layer is not recognizable, and neoplastic tissue seems to have spread into the mesorectal fat (arrowheads), a finding that represents one of the most frequent causes of overstaging. The perirectal fat stranding is actually due to a peritumoral desmoplastic reaction. (b) Photomicrograph (original magnification, x4; H-E stain) shows neoplastic glands (arrow) disrupting the muscular layer. A strong desmoplastic reaction (arrowheads) involving the fat tissue (FT) is also evident. (c) Photograph of a section of the explanted mesorectum shows the neoplastic lesion (*) and desmoplastic involvement of the perirectal fat (arrow).
|
|
View larger version (114K):
[in a new window]
|
Figure 13c. Stage T2 tumor with a peritumoral desmoplastic reaction. (a) Axial turbo spin-echo T2-weighted MR image shows a neoplastic lesion (*). The muscular layer is not recognizable, and neoplastic tissue seems to have spread into the mesorectal fat (arrowheads), a finding that represents one of the most frequent causes of overstaging. The perirectal fat stranding is actually due to a peritumoral desmoplastic reaction. (b) Photomicrograph (original magnification, x4; H-E stain) shows neoplastic glands (arrow) disrupting the muscular layer. A strong desmoplastic reaction (arrowheads) involving the fat tissue (FT) is also evident. (c) Photograph of a section of the explanted mesorectum shows the neoplastic lesion (*) and desmoplastic involvement of the perirectal fat (arrow).
|
|
View larger version (160K):
[in a new window]
|
Figure 14. Rectal adenocarcinoma with involvement of the sphincter. Coronal turbo spin-echo T2-weighted MR image shows a tumor (T) of the rectal ampulla causing stenosis of the rectal lumen and infiltrating the sphincteral plane, which is composed of the internal muscular sphincter (*) and the external sphincter (ES). The levator ani muscle (L) is also evident and appears to be uninvolved.
|
|
View larger version (178K):
[in a new window]
|
Figure 15a. Rectal adenocarcinoma with metastatic lymphadenopathy. (a) Coronal turbo spin-echo T2-weighted MR image demonstrates a rectal tumor (*) and two enlarged lymph nodes within the mesorectal fat (arrowhead). (b) Photomicrograph (original magnification, x4; H-E stain) shows neoplastic involvement of one lymph node (*), a finding that confirmed suspicions raised at radiologic evaluation.
|
|
View larger version (170K):
[in a new window]
|
Figure 15b. Rectal adenocarcinoma with metastatic lymphadenopathy. (a) Coronal turbo spin-echo T2-weighted MR image demonstrates a rectal tumor (*) and two enlarged lymph nodes within the mesorectal fat (arrowhead). (b) Photomicrograph (original magnification, x4; H-E stain) shows neoplastic involvement of one lymph node (*), a finding that confirmed suspicions raised at radiologic evaluation.
|
|
Copyright © 2006 by the Radiological Society of North America.
