title: Apparent diffusion coefficient in the evaluation of side-specific extracapsular extension in prostate cancer: Development and external validation of a nomogram of clinical use.
abstract: The aim of this study is to develop a nomogram of clinical utility based on apparent diffusion coefficient (ADC) from diffusion-weighted imaging to predict extracapsular extension (ECE), and to validate externally its clinical utility.
  
  
  
  A total of 101 men (70 for the creation and 31 for external validation of the nomogram) underwent 1.5T multiparametric magnetic resonance imaging followed by radical prostatectomy at 2 different institutions. ADC values were assessed for normal and pathological tissue. Clinical and pathological variables were investigated by univariate and multivariate logistic regression analyses on 70 patients and logistic regression coefficients were used to develop our nomogram. Receiver operating characteristic curve analysis was performed to determine the optimal ADC cut off for ECE. The nomogram was then externally validated on 31 patients at another institution.
  
  
  
  At univariate analysis, the following variables were associated with ECE: pathological ADC and Gleason at biopsy (P<0.001) along with tumor volume and ECE at imaging (P = 0.003). At multivariate analysis, pathological ADC (P = 0.027), tumor volume (P = 0.011), and biopsy Gleason (P = 0.040) maintained their independent predictor status and were included in our nomogram together with normal ADC and ECE at imaging. Our nomogram showed a significant higher sensitivity (88%) than T2-weighted imaging (54%; P = 0.010). External validation resulted in an overall accuracy of 81%.
  
  
  
  ADC represents a potential imaging biomarker to predict side-specific ECE in patients with prostate cancer. Our nomogram could improve the current diagnostic pathway and possibly the therapeutic approach for this disease.
authors.affiliation: Department of Radiology, Centre for Experimental Imaging, San Raffaele Scientific Institute, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy. Electronic address: Giganti.fra@gmail.com.
authors.forename: Francesco
authors.initials: F
authors.lastname: Giganti
authors.affiliation: Department of Radiology, Centre for Experimental Imaging, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Coppola
authors.affiliation: Vita-Salute San Raffaele University, Milan, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ambrosi
authors.affiliation: Department of Radiology, Centre for Experimental Imaging, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Ravelli
authors.affiliation: Department of Radiology, Centre for Experimental Imaging, San Raffaele Scientific Institute, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Esposito
authors.affiliation: Department of Pathology, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Freschi
authors.affiliation: Vita-Salute San Raffaele University, Milan, Italy; Department of Urology, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Briganti
authors.affiliation: Vita-Salute San Raffaele University, Milan, Italy; Department of Urology, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Scattoni
authors.affiliation: Vita-Salute San Raffaele University, Milan, Italy; Department of Urology, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Salonia
authors.affiliation: Department of Urology, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Gallina
authors.affiliation: Department of Urology, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Dehò
authors.affiliation: Department of Radiology, San Raffaele-Turro Hospital, Milan, Italy.
authors.forename: Gianpiero
authors.initials: G
authors.lastname: Cardone
authors.affiliation: Department of Radiology, San Raffaele-Turro Hospital, Milan, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Balconi
authors.affiliation: Department of Urology, San Raffaele-Turro Hospital, Milan, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Gaboardi
authors.affiliation: Vita-Salute San Raffaele University, Milan, Italy; Department of Urology, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Montorsi
authors.affiliation: Department of Radiology, Centre for Experimental Imaging, San Raffaele Scientific Institute, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy.
authors.forename: Alessandro Del
authors.initials: AD
authors.lastname: Maschio
authors.affiliation: Department of Radiology, Centre for Experimental Imaging, San Raffaele Scientific Institute, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: De Cobelli
mesh_terms: D000368:Aged; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D049451:Nomograms; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology; D012189:Retrospective Studies
keywords: Diffusion-weighted MRI; Nomograms; Prostatic neoplasms