Doenja M J Lambregts1, Andrea Delli Pizzi1,2, Max J Lahaye1, Joost J M van Griethuysen1,3, Monique Maas1, Geerard L Beets3,4, Frans C H Bakers5, Regina G H Beets-Tan1,3. 1. Department of Radiology, Netherlands Cancer Institute, Amsterdam, The Netherlands. 2. Department of Neuroscience and Imaging, Gabriele d'Annunzio University, SS Annunziate Hospital, Chieti, Italy. 3. GROW School for Oncology and Developmental Biology, Maastricht University, Maastricht, The Netherlands. 4. Department of Surgery, Netherlands Cancer Institute, Amsterdam, The Netherlands. 5. Department of Radiology, Maastricht University Medical Centre, Maastricht, The Netherlands.
Abstract
BACKGROUND: Diffusion-weighted imaging is increasingly used in rectal cancer MRI to assess response after chemoradiotherapy. Certain pitfalls (eg, artefacts) may hamper diffusion-MRI assessment, leading to suboptimal diagnostic performance. Combining diffusion-weighted MRI with the underlying morphology on standard (T2-weighted) MRI may help overcome these pitfalls. OBJECTIVE: The purpose of this study was to evaluate the diagnostic performance of a pattern-based approach combining tumor morphology on T2-weighted MRI with distinct diffusion-weighted imaging signal patterns to assess response after chemoradiotherapy in rectal cancer. DESIGN: Response to chemoradiotherapy was scored according to 4 patterns: 1) cases with either a clear residual mass with corresponding high-diffusion signal (A+) or completely normalized wall without diffusion signal (A-); 2) cases with circular and/or irregular fibrosis with (B+) or without (B-) small foci of diffusion signal scattered throughout the fibrosis; 3) cases with semicircular fibrosis with (C+) or without (C-) high diffusion signal at the inner margin of the fibrosis; and 4) polypoid tumors showing regression of the polyp and fibrosis at the site of the stalk with (D+) or without (D-) focal high-diffusion signal in the stalk. A total of 75 cases were rescored by an independent second reader to study interobserver variations. Standard of reference was histopathology or long-term outcome. SETTINGS: The study was conducted at a single tertiary referral center. PATIENTS: A total of 222 patients with locally advanced rectal cancer undergoing chemoradiotherapy were included. MAIN OUTCOME MEASURES: Diagnostic performance to discriminate between a complete response and residual tumor was measured. RESULTS: The pattern-based approach resulted in a sensitivity of 94%, specificity of 77%, positive predictive value of 88%, negative predictive value of 87%, and overall accuracy of 88% to differentiate between tumor versus complete response. Accuracies per pattern were 100% (A), 74% (B), 86% (C), and 92% (D). Interobserver agreement was good (κ = 0.75). LIMITATIONS: The study included no comparison with routine (nonpattern) diffusion-MRI assessment. CONCLUSIONS: A pattern-based approach combining tumor morphology with distinct diffusion-weighted imaging patterns results in good diagnostic performance to assess response. See Video Abstract at http://links.lww.com/DCR/A433.
BACKGROUND: Diffusion-weighted imaging is increasingly used in rectal cancer MRI to assess response after chemoradiotherapy. Certain pitfalls (eg, artefacts) may hamper diffusion-MRI assessment, leading to suboptimal diagnostic performance. Combining diffusion-weighted MRI with the underlying morphology on standard (T2-weighted) MRI may help overcome these pitfalls. OBJECTIVE: The purpose of this study was to evaluate the diagnostic performance of a pattern-based approach combining tumor morphology on T2-weighted MRI with distinct diffusion-weighted imaging signal patterns to assess response after chemoradiotherapy in rectal cancer. DESIGN: Response to chemoradiotherapy was scored according to 4 patterns: 1) cases with either a clear residual mass with corresponding high-diffusion signal (A+) or completely normalized wall without diffusion signal (A-); 2) cases with circular and/or irregular fibrosis with (B+) or without (B-) small foci of diffusion signal scattered throughout the fibrosis; 3) cases with semicircular fibrosis with (C+) or without (C-) high diffusion signal at the inner margin of the fibrosis; and 4) polypoid tumors showing regression of the polyp and fibrosis at the site of the stalk with (D+) or without (D-) focal high-diffusion signal in the stalk. A total of 75 cases were rescored by an independent second reader to study interobserver variations. Standard of reference was histopathology or long-term outcome. SETTINGS: The study was conducted at a single tertiary referral center. PATIENTS: A total of 222 patients with locally advanced rectal cancer undergoing chemoradiotherapy were included. MAIN OUTCOME MEASURES: Diagnostic performance to discriminate between a complete response and residual tumor was measured. RESULTS: The pattern-based approach resulted in a sensitivity of 94%, specificity of 77%, positive predictive value of 88%, negative predictive value of 87%, and overall accuracy of 88% to differentiate between tumor versus complete response. Accuracies per pattern were 100% (A), 74% (B), 86% (C), and 92% (D). Interobserver agreement was good (κ = 0.75). LIMITATIONS: The study included no comparison with routine (nonpattern) diffusion-MRI assessment. CONCLUSIONS: A pattern-based approach combining tumor morphology with distinct diffusion-weighted imaging patterns results in good diagnostic performance to assess response. See Video Abstract at http://links.lww.com/DCR/A433.
Authors: Hester E Haak; Monique Maas; Max J Lahaye; Thierry N Boellaard; Andrea Delli Pizzi; Casper Mihl; Dennis van der Zee; Cristina Fabris; Marit E van der Sande; Jarno Melenhorst; Regina G H Beets-Tan; Geerard L Beets; Doenja M J Lambregts Journal: Ann Surg Oncol Date: 2020-03-14 Impact factor: 5.344
Authors: Seth I Felder; Sebastian Feuerlein; Arthur Parsee; Iman Imanirad; Julian Sanchez; Sophie Dessureault; Richard Kim; Sarah Hoffe; Jessica Frakes; James Costello Journal: Abdom Radiol (NY) Date: 2020-10-28
Authors: Emmanouil Fokas; Ane Appelt; Alexandra Gilbert; David Sebag-Montefiore; Claus Rödel; Robert Glynne-Jones; Geerard Beets; Rodrigo Perez; Julio Garcia-Aguilar; Eric Rullier; J Joshua Smith; Corrie Marijnen; Femke P Peters; Maxine van der Valk; Regina Beets-Tan; Arthur S Myint; Jean-Pierre Gerard; Simon P Bach; Michael Ghadimi; Ralf D Hofheinz; Krzysztof Bujko; Cihan Gani; Karin Haustermans; Bruce D Minsky; Ethan Ludmir; Nicholas P West; Maria A Gambacorta; Vincenzo Valentini; Marc Buyse; Andrew G Renehan Journal: Nat Rev Clin Oncol Date: 2021-08-04 Impact factor: 66.675