Comparison of semi-automated and manual methods to measure the volume of prostate cancer on magnetic resonance imaging.
OBJECTIVE
The purpose of this study was to determine the accuracy of manual semi-automated and volumetric measurements to assess prostate cancer volume on multiparametric magnetic resonance imaging (MP-MRI) using whole-mount histopathology for validation.


METHODS
We evaluated 30 consecutive men (median age, 65.7 years; interquartile range [IQR], 61.5-70.9 years) with a median prostatic specific antigen of 8.5ng/dL (IQR, 5.5-10.5ng/dL), who underwent MP-MRI before radical prostatectomy. Index tumor volume was determined prospectively and independently on the basis of MRI and whole-mount section volumetric assessment using the maximum histologic diameter (MHD) and the histologic volume (HV). The MRI index tumor volume was determined by two independent radiologists using a single measurement of the maximum tumor dimension (MTD), a simplified MR ellipsoid volume (MREV) calculation and a MR region of interest volume (MROV) segmentation displayed by a commercially available OsiriX®. MTD was compared to MHD, whereas MREV and MROV were compared to HV.


RESULTS
Thirty index lesions (median HV, 1.514 cm3; IQR, 0.05-3.780 cm3) were analyzed. The MREV, MROV and HD were significantly correlated with each other (r>0.5). Inter-observer agreement for measurements was good for each method (r>0.780). The MTD was the best predictor of maximum histologic diameter (r=0.980 and 0.791) and had an excellent inter-variability correlation (P<0.0001).


CONCLUSIONS
Prostate cancer histologic volume can be assessed using MREV or MROV with a good accuracy and low inter-observer variability. MTD has the lowest inter-observer variability and provides best degrees of correlation with MHD. MTD should be used on MRI for selecting and following patients for active surveillance and staging before focal treatment of prostate cancer.
Pontifical Catholic University of Peru, Engineering Department, Electrical and Electronics Section, Medical Imaging Lab, San Miguel, Lima 32, Peru.
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Marin
Academic Department of Radiology, Hôpital Pitié-Salpêtrière, AP-HP, UPMC University Paris 06, 75013 Paris, France.
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Ezziane
Academic Department of Pathology, Hôpital Tenon, AP-HP, UPMC University Paris 06, 75020 Paris, France.
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Comperat
Academic Department of Urology, Hôpital Pitié-Salpêtrière, AP-HP, UPMC University Paris 06, 75013 Paris, France.
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Mozer
GRC5, ONCOTYPE-Uro, Institut Universitaire de Cancérologie, 75020 Paris, France.
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Cancel-Tassin
Academic Department of Pathology, Hôpital Pitié-Salpêtrière, AP-HP, UPMC University Paris 06, 75013 Paris, France.
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Coté
Pontifical Catholic University of Peru, Engineering Department, Electrical and Electronics Section, Medical Imaging Lab, San Miguel, Lima 32, Peru.
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Racoceanu
Academic Department of Radiology, Tenon, Pitié-Salpêtrière Hospitals, AP-HP, UPMC University Paris 06, Paris, France.
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Boudghene
Academic Department of Radiology, Hôpital Pitié-Salpêtrière, AP-HP, UPMC University Paris 06, 75013 Paris, France.
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Lucidarme
GRC5, ONCOTYPE-Uro, Institut Universitaire de Cancérologie, 75020 Paris, France; Academic Department of Urology, Hôpital Tenon, AP-HP, UPMC University Paris 06, 75020 Paris, France.
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Cussenot
Academic Department of Radiology, Hôpital Pitié-Salpêtrière, AP-HP, UPMC University Paris 06, 75013 Paris, France; GRC5, ONCOTYPE-Uro, Institut Universitaire de Cancérologie, 75020 Paris, France; Academic Department of Radiology, Tenon, Pitié-Salpêtrière Hospitals, AP-HP, UPMC University Paris 06, Paris, France. Electronic address: raphaele.renardpenna@aphp.fr.
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Renard Penna
D000368:Aged; D001331:Automation; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000000981:diagnostic imaging* / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D047368:Tumor Burden
Comparative studies; Index lesion; Magnetic resonance imaging (MRI); Prostate neoplasms; Tumor volume