Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Mar;46(3):867-872.
doi: 10.1007/s00261-020-02757-3. Epub 2020 Sep 17.

Measurement of rectal tumor height from the anal verge on MRI: a comparison of internal versus external anal sphincter

David D B Bates  1 , James L Fuqua 3rd  2 , Junting Zheng  3 , Marinela Capanu  3 , Jennifer S Golia Pernicka  2 , Sidra Javed-Tayyab  2 , Viktoriya Paroder  2 , Iva Petkovska  2 , Marc J Gollub  2
Affiliations

Measurement of rectal tumor height from the anal verge on MRI: a comparison of internal versus external anal sphincter

David D B Bates et al. Abdom Radiol (NY). 2021 Mar.

Abstract

Purpose: To determine the most accurate measurement technique to assess rectal tumor height on MRI using two different anatomic landmarks for the anal verge.

Introduction: Accurate measurements and standardized reporting of MRI for rectal cancer staging is essential. It is not known whether measurements starting from the internal anal sphincter (IAS) or external anal sphincter (EAS) more closely correlate with tumor height from the anal verge on endoscopy.

Methods: This retrospective study included baseline staging MRI examinations for 85 patients after exclusions. Two radiologists blinded to endoscopic results measured the distance of rectal tumors from the internal anal sphincter and external anal sphincter on sagittal T2 images. The reference standard was endoscopic measurement of tumor height; descriptive statistics were performed.

Results: For reader 1, the mean difference in measurement of tumor height between MRI and endoscopy was - 0.45 cm (SD ± 1.76 cm, range - 6.0 to 3.9 cm) for the IAS and 0.51 cm (SD ± 1.75 cm range - 4.7 to 4.8 cm) for the EAS. For reader 2, the mean difference in measurement of tumor height between MRI and endoscopy was - 0.57 (STD ± 1.81, range - 5.9 to 4.8 cm) for the IAS and 0.52 cm (STD ± 1.85, range - 4.3 to 5.6 cm) for the EAS. Interobserver ICC was excellent between reader 1 and reader 2 for measurements from both the IAS (0.955 95% CI 0.931-0.97) and EAS (0.952, 95% CI 0.928, 0.969).

Conclusion: Measurement of tumor height on MRI was highly reproducible between readers; beginning measurements from the EAS tends to slightly overestimate tumor height on average and from the IAS tends to slightly underestimate tumor height on average.

Keywords: Anal canal; Anal verge; Measurement; Rectal MRI; Rectal cancer; Tumor height.

PubMed Disclaimer

Conflict of interest statement

Conflict of Interest: The authors have no conflicts of interest.

Figures

Figure 1:
Figure 1:
37-year old female with rectal adenocarcinoma. Sagittal T2-weighted image through the rectum shows measurements as drawn from the internal anal sphincter (a, solid line), from the external anal sphincter (b, solid line) and from the anorectal junction to the inferior margin of the tumor (a and b, dotted lines). The T2-hyperintense fat located between the sphincters, the intersphincteric groove, is well seen in this case (c, arrowhead).
Figure 2:
Figure 2:
Boxplot of image distance differences from endoscopy.
Figure 3:
Figure 3:
Scatter plot of image differences with endoscopy measurements on endoscopy. Plots with linear regression fitted curves and adjusted R-square estimates.
Figure 4:
Figure 4:
Bland-Altman plot between readers.
See this image and copyright information in PMC

References

    1. Siegel RL, Fedewa SA, Anderson WF, Miller KD, Ma J, Rosenberg PS, Jemal A (2017) Colorectal Cancer Incidence Patterns in the United States, 1974–2013. Journal of the National Cancer Institute 109 (8). doi:10.1093/jnci/djw322 - DOI - PMC - PubMed
    1. Khan MAS, Ang CW, Hakeem AR, Scott N, Saunders RN, Botterill I (2017) The Impact of Tumour Distance From the Anal Verge on Clinical Management and Outcomes in Patients Having a Curative Resection for Rectal Cancer. J Gastrointest Surg 21 (12):2056–2065. doi:10.1007/s11605-017-3581-0 - DOI - PubMed
    1. Duan X, Zhao M, Zhang S, Xu Z, Mi L, Shi J, Ma X, Liu Y, Li N, Yin X, Han X, Han G, Wang J, Xu J, Yin F (2020) Effects of tumor distance from anal verge on survival outcomes for rectal NENs and lymphatic metastasis risk score for colorectal NENs. Int J Colorectal Dis 35 (7):1255–1264. doi:10.1007/s00384-020-03596-w - DOI - PubMed
    1. Augestad KM, Keller DS, Bakaki PM, Rose J, Koroukian SM, Oresland T, Delaney CP (2018) The impact of rectal cancer tumor height on recurrence rates and metastatic location: A competing risk analysis of a national database. Cancer Epidemiol 53:56–64. doi:10.1016/j.canep.2018.01.009 - DOI - PubMed
    1. Gupta NA, Mahajan S, Sumankumar A, Saklani A, Engineer R, Baheti AD (2020) Impact of a standardized reporting format on the quality of MRI reports for rectal cancer staging. Indian J Radiol Imaging 30 (1):7–12. doi:10.4103/ijri.IJRI_308_19 - DOI - PMC - PubMed

Publication types

MeSH terms