Measurement of enhancement kinetics using heuristic parameters in multiparametric MRI as markers of prostate cancer aggressiveness.

BackgroundDynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has been used as a diagnostic modality with known added value in multi-parametric MRI (mp-MRI) characterisation of prostate cancers (PCa). Several methods have been applied to analyse DCE MRI data. The purpose of this study is to assess the ability of mp-MRI for detecting grade of prostate carcinomas in comparison to pathology using heuristic model-free parametric evaluation (wash-in and wash-out slope, etc.) provided by Tissue 4D (Siemens Multi-Modality Work Platform).Method21 patients with histologically proven prostate cancer who were scanned at 3T mp-MRI and opted for laparoscopic radical prostatectomy were recruited in this study. Post-prostatectomy pathology reports were considered as reference standard. The pathology specimens were processed by a special method to ensure exact orientation between imaging and slices of section during histopathology. Multi-parametric MRI data including conventional T1 and T2 weighted imaging (T1WI and T2WI), DWI and DCE-MRI was recorded. DCE-MRI was analysed in Tissue 4D using the two different methods: tofts model (Ktrans, kep values and the colour-distribution map for the perfusion parameters); wash-in and –out rates, which were calculated according to the parametric time-concentration curves.ResultsThere are 46 lesions detected in pathology of 21 prostatectomy specimen and mp-MRI correctly picked up 33 of them. Smaller lesions (2mm and less) with Gleason grade 3+4 were not identified by DCE-MRI. There was a strong trend towards a positive correlation between grade of cancer and enhancement rate as assessed by toft model.ConclusionDCE-MRI with the two difference methods could predict aggressiveness of prostate cancers more than 2mm in size. Smaller lesions and those with Gleason score 7 and less could still be a challenge for multiparamteric MRI detection method.</p

Orientation of imaging and histology of radical prostatectomy specimen in prostate cancer using 3D modelling and fabricated molds

BackgroundTo develop patient-specific 3T MRI data based rapid prototyping molds for sectioning prostatectomy specimens that would facilitate comparison between histopathology, in vivo MRI and Shear Wave Elastography (SWE).MethodPost-radical prostatectomy specimens were fixed in formalin and sectioned in similar orientation to T2-weighted MR scanning. This was facilitated by the use of mold prepared in biomedical software Mimics (Materialise, Belgium) and CAD software Solidworkds (Dassault Systèmes SolidWorks Corp., USA) through 3-D segmentation, reconstruction and rapid prototyping. The specimens were sliced with a single blade and the resultant MRI images defined tissue blocks were used for histopathology analysis. The multi-parametric MRI data, SWE and histological sectioning were compared to assess prostate cancer characteristics.ResultsThe prostatectomy specimen slices were very uniform in thickness with good quality histological sectioning. A number of cancer foci were picked up with some of them significant disease (Gleason grade 7 and more). Multiparametric MRI (mp-MRI), quantitative SWE data as measured in kilopascals and histopathology comparison showed good correspondence between the three images.ConclusionThe method described here allows a reliable orientation and comparison between imaging (mp-MRI, SWE) and histology of prostatectomy specimens and paves the way for the translation of imaging biomarkers, especially detection of significant cancers.</p

Computer aided image analysis and rapid prototyping molds using patient-specific MRI data for reliable comparison between imaging and histopathology of radical prostatectomy specimens

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