Three-dimensional segmentation of retroperitoneal masses using continuous convex relaxation and accumulated gradient distance for radiotherapy planning.
An innovative algorithm has been developed for the segmentation of retroperitoneal tumors in 3D radiological images. This algorithm makes it possible for radiation oncologists and surgeons semiautomatically to select tumors for possible future radiation treatment and surgery. It is based on continuous convex relaxation methodology, the main novelty being the introduction of accumulated gradient distance, with intensity and gradient information being incorporated into the segmentation process. The algorithm was used to segment 26 CT image volumes. The results were compared with manual contouring of the same tumors. The proposed algorithm achieved 90 % sensitivity, 100 % specificity and 84 % positive predictive value, obtaining a mean distance to the closest point of 3.20 pixels. The algorithm's dependence on the initial manual contour was also analyzed, with results showing that the algorithm substantially reduced the variability of the manual segmentation carried out by different specialists. The algorithm was also compared with four benchmark algorithms (thresholding, edge-based level-set, region-based level-set and continuous max-flow with two labels). To the best of our knowledge, this is the first time the segmentation of retroperitoneal tumors for radiotherapy planning has been addressed.
Technological Innovation Group, Virgen del Rocío University Hospital, Seville, Spain. cristina.suarez.exts@juntadeandalucia.es.|Signal Theory and Communications Department, University of Seville, Seville, Spain. cristina.suarez.exts@juntadeandalucia.es.
Cristina
C
Suárez-Mejías
Signal Theory and Communications Department, University of Seville, Seville, Spain.
Jose Antonio
JA
Pérez-Carrasco
Signal Theory and Communications Department, University of Seville, Seville, Spain.
Carmen
C
Serrano
Oncology Unit, Virgen del Rocío University Hospital, Seville, Spain.
Jose Luis
JL
López-Guerra
Technological Innovation Group, Virgen del Rocío University Hospital, Seville, Spain.
Carlos
C
Parra-Calderón
Surgery Unit, Virgen del Rocío University Hospital, Seville, Spain.
Tomás
T
Gómez-Cía
Signal Theory and Communications Department, University of Seville, Seville, Spain.
Begoña
B
Acha
D000293:Adolescent; D000328:Adult; D000465:Algorithms; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D016014:Linear Models; D008297:Male; D015588:Observer Variation; D011880:Radiotherapy Planning, Computer-Assisted; D012186:Retroperitoneal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D055815:Young Adult
Computed tomography; Convex relaxation; Image segmentation; Retroperitoneal tumor