Validation of pelvic magnetic resonance imaging as the method of choice to determine the distance to the anal margin in rectal cancer

INTRODUCTION

Distance from anal verge of rectal tumours and their anatomical relationships contribute to determine the multidisciplinary therapeutic strategy based on the combination of radio-chemotherapy and radical surgery. Our aims are to investigate which is the most accurate method for the preoperative measuring of the distance from the anal verge in rectal tumours and if the pelvic MRI can substitute the classical instrumental methods.

METHODS

Prospective study of diagnostic precision between flexible colonoscopy (FC), preoperative rigid rectosigmoidoscopy (pRR) and pelvic MRI in patients scheduled to radical surgery. Rigid intraoperative rectoscopy (iRR) was considered the reference test. The correlations between the different techniques and their determination coefficient as well as the intraclass correlation coefficient and the degree of agreement between the different tests were analyzed.

RESULTS

96 patients (65% males), mean age (SD): 68 (14.1) years were included. 72% received neoadjuvant treatment. The mean distance to the anal margin measured by FC = 103.5 mm, was significantly greater than others, which had similar values: pRR = 81.1; MRI = 77.4; iRR = 82.9 mm (P < .001). A significant intraclass correlation was observed and there was high agreement between all pre- and intraoperative measurements except for the performed by FC, which overestimated the results. MRI provided more individualized and accurate information.

CONCLUSIONS

There is variability between the measurement methods, being colonoscopy the least reliable. MRI offers objective, comparable, accurate and individualized values that can replace those obtained by pRR for tumours of any location in the rectum.

Validation of pelvic magnetic resonance imaging as the method of choice to determine the distance to the anal margin in rectal cancer

INTRODUCTION

Distance from anal verge of rectal tumors and their anatomical relationships contribute to determine the multidisciplinary therapeutic strategy based on the combination of radio-chemotherapy and radical surgery. Our aims are to investigate which is the most accurate method for the preoperative measuring of the distance from the anal verge in rectal tumors and if the pelvic MRI can substitute the classical instrumental methods.

METHODS

Prospective study of diagnostic precision between flexible colonoscopy (FC), preoperative rigid rectosigmoidoscopy (pRR) and pelvic MRI in patients scheduled to radical surgery. Rigid intraoperative rectoscopy (iRR) was considered the reference test. The correlations between the different techniques and their determination coefficient as well as the intraclass correlation coefficient and the degree of agreement between the different tests were analyzed.

RESULTS

96 patients (65% males), mean age (SD): 68 (14.1) years were included. 72% received neoadjuvant treatment. The mean distance to the anal margin measured by FC=103.5mm, was significantly greater than others, which had similar values: pRR=81.1; MRI=77.4; iRR=82.9mm (P<.001). A significant intraclass correlation was observed and there was high agreement between all pre- and intraoperative measurements except for the performed by FC, which overestimated the results. MRI provided more individualized and accurate information.

CONCLUSIONS

There is variability between the measurement methods, being colonoscopy the least reliable. MRI offers objective, comparable, accurate and individualized values that can replace those obtained by pRR for tumors of any location in the rectum.

[Rectal tonsil or lymphoid follicular hyperplasia of the rectum]

The rectal tonsil is a reactive proliferation of lymphoid tissue located in the rectum. The morphology of the lymphoid proliferation of the colon is usually polypoid or, less commonly, nodular. Only in exceptional cases does lymphoid proliferation of the colon present as a mass in the rectum (rectal tonsil), although this is the most common presentation in middle-aged patients. It is important to be familiar with the rectal tonsil because in cases of exuberant growth it can be difficult to distinguish it from other types of masses. We present the case of rectal tonsil in a four-year-old girl. We describe the magnetic resonance imaging findings and review the literature.