Yeo Eun Han1, Beom Jin Park2, Deuk Jae Sung1, Min Ju Kim1, Na Yeon Han1, Ki Choon Sim1, Sung Bum Cho1, Jin Kim3, Seon-Hahn Kim3, Hyonggin An4. 1. Department of Radiology, Korea University Anam Hospital, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea. 2. Department of Radiology, Korea University Anam Hospital, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea. radiolbj226@gmail.com. 3. Department of Surgery, Korea University Anam Hospital, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea. 4. Department of Biostatistics, Korea University College of Medicine, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea.
Abstract
PURPOSE: To determine an accurate method for localizing rectal cancer using the distance from the anal verge on preoperative MRI. METHODS: This prospective study included 50 patients scheduled for MRI evaluation of rectal cancer. After rectal filling with gel, MRI was performed with two markers attached at the anal verge. The distance between the tumor and the anal verge on a sagittal T2-weighted image (T2WI) was measured independently by two radiologists using six methods divided into three groups of similar measurement approaches, and compared to those obtained on rigid sigmoidoscopy. The anal verge location relative to the external anal sphincter was assessed on oblique coronal T2WI in reference to the markers. Correlation analysis was performed using the intraclass correlation coefficient (ICC) for verification, and a paired t test was used to evaluate the mean differences. RESULTS: The highest correlation (ICC 0.797-0.815) and the least mean difference (0.74-0.85 cm) with rigid sigmoidoscopy, and the least standard deviation (3.12-3.17 cm) were obtained in the direct methods group using a straight line from the anal verge to the tumor. The anal verge was localized within a range of - 1.4 to 1.5 cm (mean - 0.31 cm and - 0.22 cm) from the lower end of the external anal sphincter. CONCLUSION: The direct methods group provided the most accurate tumor distance among the groups. Among the direct methods, we recommend the direct mass method for its simplicity. Despite minor differences in location, the lower end of the external anal sphincter was a reliable anatomical landmark for the anal verge.
PURPOSE: To determine an accurate method for localizing rectal cancer using the distance from the anal verge on preoperative MRI. METHODS: This prospective study included 50 patients scheduled for MRI evaluation of rectal cancer. After rectal filling with gel, MRI was performed with two markers attached at the anal verge. The distance between the tumor and the anal verge on a sagittal T2-weighted image (T2WI) was measured independently by two radiologists using six methods divided into three groups of similar measurement approaches, and compared to those obtained on rigid sigmoidoscopy. The anal verge location relative to the external anal sphincter was assessed on oblique coronal T2WI in reference to the markers. Correlation analysis was performed using the intraclass correlation coefficient (ICC) for verification, and a paired t test was used to evaluate the mean differences. RESULTS: The highest correlation (ICC 0.797-0.815) and the least mean difference (0.74-0.85 cm) with rigid sigmoidoscopy, and the least standard deviation (3.12-3.17 cm) were obtained in the direct methods group using a straight line from the anal verge to the tumor. The anal verge was localized within a range of - 1.4 to 1.5 cm (mean - 0.31 cm and - 0.22 cm) from the lower end of the external anal sphincter. CONCLUSION: The direct methods group provided the most accurate tumor distance among the groups. Among the direct methods, we recommend the direct mass method for its simplicity. Despite minor differences in location, the lower end of the external anal sphincter was a reliable anatomical landmark for the anal verge.
Authors: Angelo Restivo; Luigi Zorcolo; Ivana Maria Francesca Cocco; Romina Manunza; Carla Margiani; Luigi Marongiu; Giuseppe Casula Journal: Ann Surg Oncol Date: 2012-09-26 Impact factor: 5.344
Authors: Regina G H Beets-Tan; Doenja M J Lambregts; Monique Maas; Shandra Bipat; Brunella Barbaro; Luís Curvo-Semedo; Helen M Fenlon; Marc J Gollub; Sofia Gourtsoyianni; Steve Halligan; Christine Hoeffel; Seung Ho Kim; Andrea Laghi; Andrea Maier; Søren R Rafaelsen; Jaap Stoker; Stuart A Taylor; Michael R Torkzad; Lennart Blomqvist Journal: Eur Radiol Date: 2017-10-17 Impact factor: 5.315