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Imaging in rectal cancer with emphasis on local staging with MRI.

Arya S, Das D, Engineer R, Saklani A - Indian J Radiol Imaging (2015 Apr-Jun)

Bottom Line: Contrast-enhanced MRI is considered inappropriate for both primary staging and restaging.Diffusion-weighted sequence may be of value in restaging.Multidetector CT cannot replace MRI in local staging, but has an important role for evaluating distant metastases.

View Article: PubMed Central - PubMed

Affiliation: Department of Radio-Diagnosis, Tata Memorial Centre, Mumbai, Maharashtra, India.

ABSTRACT
Imaging in rectal cancer has a vital role in staging disease, and in selecting and optimizing treatment planning. High-resolution MRI (HR-MRI) is the recommended method of first choice for local staging of rectal cancer for both primary staging and for restaging after preoperative chemoradiation (CT-RT). HR-MRI helps decide between upfront surgery and preoperative CT-RT. It provides high accuracy for prediction of circumferential resection margin at surgery, T category, and nodal status in that order. MRI also helps assess resectability after preoperative CT-RT and decide between sphincter saving or more radical surgery. Accurate technique is crucial for obtaining high-resolution images in the appropriate planes for correct staging. The phased array external coil has replaced the endorectal coil that is no longer recommended. Non-fat suppressed 2D T2-weighted (T2W) sequences in orthogonal planes to the tumor are sufficient for primary staging. Contrast-enhanced MRI is considered inappropriate for both primary staging and restaging. Diffusion-weighted sequence may be of value in restaging. Multidetector CT cannot replace MRI in local staging, but has an important role for evaluating distant metastases. Positron emission tomography-computed tomography (PET/CT) has a limited role in the initial staging of rectal cancer and is reserved for cases with resectable metastatic disease before contemplating surgery. This article briefly reviews the comprehensive role of imaging in rectal cancer, describes the role of MRI in local staging in detail, discusses the optimal MRI technique, and provides a synoptic report for both primary staging and restaging after CT-RT in routine practice.

No MeSH data available.


Related in: MedlinePlus

(A) Axial T2W MRI shows a hyperintense mucin containing node in the left periprostatic region (arrow), which could be overlooked due to inadequate contrast. (B) Axial T1W MRI shows the node (arrow) which is hypointense against the bright fat
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Figure 9: (A) Axial T2W MRI shows a hyperintense mucin containing node in the left periprostatic region (arrow), which could be overlooked due to inadequate contrast. (B) Axial T1W MRI shows the node (arrow) which is hypointense against the bright fat

Mentions: T staging reflects the extent of the tumor within the rectal wall and extramural spread into the perirectal tissues and organs [Table 1 and Figure 8]. A recent meta-analysis reported an accuracy of 85%, sensitivity of 87%, and specificity of 75% for HR-MRI inT staging of rectal cancer.[33] On HR-MRI, T staging is decided by examining the T2W signal intensity of the normal rectum and of the tumor extending into the layers of the rectal walls and the mesorectal fat. The tumor usually has intermediate signal intensity on T2W MR images. However, mucinous tumors are brightly hyperintense on T2W MRI. In these tumors, where the contrast between the tumor and perirectal fat is inadequate, we find it useful to also examine the axial T1-weighted (T1W) sequence [Figure 9].


Imaging in rectal cancer with emphasis on local staging with MRI.

Arya S, Das D, Engineer R, Saklani A - Indian J Radiol Imaging (2015 Apr-Jun)

(A) Axial T2W MRI shows a hyperintense mucin containing node in the left periprostatic region (arrow), which could be overlooked due to inadequate contrast. (B) Axial T1W MRI shows the node (arrow) which is hypointense against the bright fat
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4419424&req=5

Figure 9: (A) Axial T2W MRI shows a hyperintense mucin containing node in the left periprostatic region (arrow), which could be overlooked due to inadequate contrast. (B) Axial T1W MRI shows the node (arrow) which is hypointense against the bright fat
Mentions: T staging reflects the extent of the tumor within the rectal wall and extramural spread into the perirectal tissues and organs [Table 1 and Figure 8]. A recent meta-analysis reported an accuracy of 85%, sensitivity of 87%, and specificity of 75% for HR-MRI inT staging of rectal cancer.[33] On HR-MRI, T staging is decided by examining the T2W signal intensity of the normal rectum and of the tumor extending into the layers of the rectal walls and the mesorectal fat. The tumor usually has intermediate signal intensity on T2W MR images. However, mucinous tumors are brightly hyperintense on T2W MRI. In these tumors, where the contrast between the tumor and perirectal fat is inadequate, we find it useful to also examine the axial T1-weighted (T1W) sequence [Figure 9].

Bottom Line: Contrast-enhanced MRI is considered inappropriate for both primary staging and restaging.Diffusion-weighted sequence may be of value in restaging.Multidetector CT cannot replace MRI in local staging, but has an important role for evaluating distant metastases.

View Article: PubMed Central - PubMed

Affiliation: Department of Radio-Diagnosis, Tata Memorial Centre, Mumbai, Maharashtra, India.

ABSTRACT
Imaging in rectal cancer has a vital role in staging disease, and in selecting and optimizing treatment planning. High-resolution MRI (HR-MRI) is the recommended method of first choice for local staging of rectal cancer for both primary staging and for restaging after preoperative chemoradiation (CT-RT). HR-MRI helps decide between upfront surgery and preoperative CT-RT. It provides high accuracy for prediction of circumferential resection margin at surgery, T category, and nodal status in that order. MRI also helps assess resectability after preoperative CT-RT and decide between sphincter saving or more radical surgery. Accurate technique is crucial for obtaining high-resolution images in the appropriate planes for correct staging. The phased array external coil has replaced the endorectal coil that is no longer recommended. Non-fat suppressed 2D T2-weighted (T2W) sequences in orthogonal planes to the tumor are sufficient for primary staging. Contrast-enhanced MRI is considered inappropriate for both primary staging and restaging. Diffusion-weighted sequence may be of value in restaging. Multidetector CT cannot replace MRI in local staging, but has an important role for evaluating distant metastases. Positron emission tomography-computed tomography (PET/CT) has a limited role in the initial staging of rectal cancer and is reserved for cases with resectable metastatic disease before contemplating surgery. This article briefly reviews the comprehensive role of imaging in rectal cancer, describes the role of MRI in local staging in detail, discusses the optimal MRI technique, and provides a synoptic report for both primary staging and restaging after CT-RT in routine practice.

No MeSH data available.


Related in: MedlinePlus