Volumetry of the dominant intraprostatic tumour lesion: intersequence and interobserver differences on multiparametric MRI.
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Date
2017-03-01Author
Harvey, H
Orton, MR
Morgan, VA
Parker, C
Dearnaley, D
Fisher, C
deSouza, NM
Type
Journal Article
Metadata
Show full item recordAbstract
OBJECTIVE: To establish the interobserver reproducibility of tumour volumetry on individual multiparametric (mp) prostate MRI sequences, validate measurements with histology and determine whether functional to morphological volume ratios reflect Gleason score. METHODS: 41 males with prostate cancer treated with prostatectomy (Cohort 1) or radical radiotherapy (Cohort 2), who had pre-treatment mpMRI [T2 weighted (T2W) MRI, diffusion-weighted (DW)-MRI and dynamic contrast-enhanced (DCE)-MRI], were studied retrospectively. Dominant intraprostatic lesions (DIPLs) were manually delineated on each sequence and volumes were compared between observers (n = 40 analyzable) and with radical prostatectomy (n = 20). Volume ratios of DW-MRI and DCE-MRI to T2W MRI were documented and compared between Gleason grade 3 + 3, 3 + 4 and 4 + 3 or greater categories. RESULTS: Limits of agreement of DIPL volumes between observers were: T2W MRI 0.9, -1.1 cm3, DW-MRI 1.3, -1.7 cm3 and DCE-MRI 0.74, -0.89 cm3. In Cohort 1, T2W volumes overestimated fixed specimen histological volumes (+33% Observer 1, +16% Observer 2); DW- and DCE-MRI underestimated histological volume, the latter markedly so (-32% Observer 1, -79% Observer 2). Differences between T2W, DW- and DCE-MRI volumes were significant (p < 10-8). The ratio of DW-MRI volume (73.9 ± 18.1% Observer 1, 72.5 ± 21.9% Observer 2) and DCE-MRI volume (42.6 ± 24.6% Observer 1, 34.3 ± 24.9% Observer 2) to T2W volume was significantly different (p < 10-8), but these volume ratios did not differ between the Gleason grades. CONCLUSION: The low variability of the DIPL volume on T2W MRI between Observers and agreement with histology indicates its suitability for delineation of gross tumour volume for radiotherapy planning. The volume of cellular tumour represented by DW-MRI is greater than the vascular (DCE) abnormality; ratios of both to T2W volume are independent of Gleason score. Advances in knowledge: (1) Manual volume measurement of tumour is reproducible within 1 cm3 between observers on all sequences, confirming suitability across observers for radiotherapy planning. (2) Volumes derived on T2W MRI most accurately represent in vivo lesion volumes. (3) The proportion of cellular (DW-MRI) or vascular (DCE-MRI) volume to morphological (T2W MRI) volume is not affected by Gleason score.
Collections
Subject
Prostate
Humans
Prostatic Neoplasms
Contrast Media
Image Interpretation, Computer-Assisted
Observer Variation
Magnetic Resonance Imaging
Diffusion Magnetic Resonance Imaging
Image Enhancement
Tumor Burden
Retrospective Studies
Reproducibility of Results
Aged
Male
Neoplasm Grading
Research team
Clinical Academic Radiotherapy (Dearnaley)
Magnetic Resonance
Language
eng
Date accepted
2017-01-03
License start date
2017-03
Citation
The British journal of radiology, 2017, 90 (1071), pp. 20160416 - ?
Publisher
BRITISH INST RADIOLOGY