Prostate: Clinical

Monday 22 April 2013

Michael Da Rosa^1,2, Laurent Milot^1,3, Linda Sugar^3,4, Danny Vesprini^3,5, Hans Chung^3,5, Andrew Loblaw^3,5, Laurence Klotz^3,6, and Masoom A. Haider^1,3
1Department of Medical Imaging, University of Toronto, Toronto, ON, Canada, ²Institute of Medical Science, University of Toronto, Toronto, ON, Canada,³Sunnybrook Health Sciences Centre, Toronto, ON, Canada, ⁴Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada, ⁵Radiation Oncology, University of Toronto, Toronto, ON, Canada, ⁶Division of Urology, University of Toronto, Toronto, ON, Canada

The purpose of this prospective study was to determine the ability of an MRI-US fusion biopsy system to detect clinically significant (CS) disease in active surveillance (AS) patients compared to random transrectal ultrasound (R-TRUS) guided biopsy (bx). Multiparametric MRI prospectively identified up to 4 suspicious targets in each patient. Biopsy was performed using an MRI-ultrasound navigation system (UroNav, Philips Healthcare). MRI-US fusion biopsy detected more CS cancers with fewer biopsy cores than random biopsy in AS patients. In addition, MRI in AS patients has a high negative predictive value for the presence of CS disease on subsequent biopsy.

Juan Hu¹, He Wang¹, Xuedong Yang¹, Chengyan Wang², Rui Wang¹, Ge Gao¹, Hui Zhang², Wenchao Cai¹, Wei Wang¹, Jue Zhang^2,3, and Xiaoying Wang^1,2
1Radiology Department, Peking University First Hospital, Beijing, Beijing, China, ²Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, Beijing, China, ³College of Engineering, Peking University, Beijing, Beijing, China

Multi-parameter MRI (Mp-MRI) plays an increasingly important role in the detection, localization and staging of prostate cancer (PCa). To solve the absence of unified criterion of technique and the interpretation of images of Mp-MRI in PCa detection. A recent consensus meeting of PCa experts from ESUR recommended PI-RADS scoring system. True evidence-based guidelines could not be formulated. Our retrospective study proved that PI-RADS scoring was an operable and useful scoring system for interpretation of Mp-MRI used in PCa detection. The diagnostic status of each MR sequence was not at the same level. Only appropriate combined mode was used, the excellent diagnostic efficacy of Mp-MRI can be obtained.

Nikolaos Dikaios¹, Mohamed Abd Alazeez², Mark Emberton², Taiki Fujiwara³, David Atkinson¹, and Shonit Punwani^1
1Centre for Medical Imaging, University College London, London, Greater London, United Kingdom, ²Department of Urology, University College London Hospital, London, Greater London, United Kingdom, ³Department of Radiology, University College London Hospital, London, Greater London, United Kingdom

Dynamic contrast enhancement (DCE) MRI has been advocated for detection of prostate cancer, but studies predominantly concentrate on peripheral zone tumours. Biological differences are known to exist between tumours within transition and peripheral zones due to their different microenvironment. This study aims to compare and contrast quantitative DCE MRI parameters of prostate PZ and TZ cancer and non-cancer regions; to identify those best able to classify cancer tissue at each site and thereby improve DCE MRI based diagnostic models used within computer aided detection software.

Andrew B. Rosenkrantz¹, Nicole Hindman¹, Hersh Chandarana¹, Fang-ming Deng², James S. Babb¹, Samir S. Taneja³, and Christian Geppert^4
1Radiology, NYU Langone Medical Center, New York, New York, United States, ²Pathology, NYU Langone Medical Center, New York, New York, United States,³Urologic Oncology, NYU Langone Medical Center, New York, New York, United States, ⁴Siemens Medical Systems, New York, New York, United States

49 prostate cancer patients underwent 3T MRI including DWI with b-values 50 and 1000 mm2/sec. Computed DW-images with b-value 1500 were generated from the lower b-value images without additional scan time. Directly acquired b1500 images were also obtained in 39 patients. For two independent readers, using prostatectomy as reference, computed b-1,500 images had higher sensitivity and PPV for tumor than direct b-1,000 images and no significant difference than direct b-1,500 images. Scores for diagnostic confidence, tumor conspicuity, distortion, and benign prostate tissue suppression, were also significantly better for computed b-1,500 images than for direct b-1,000 images for both readers.

Massimo Mischi¹, Kyveli Kompatsiari¹, Tamerlan Saidov¹, Marc Engelbrecht², Hessel Wijkstra^1,2, and Marcel Breeuwer^1,3
1Eindhoven University of Technology, Eindhoven, Netherlands, ²Academic Medical Center, Amsterdam, Netherlands, ³Philips Healthcare, Best, Netherlands

A new method is proposed for characterization of the microvascular architecture by assessment of contrast intravascular dispersion in dynamic contrast enhanced MRI. Dispersion is estimated by fitting a new model that integrates the Tofts model for permeability estimation together with a solution of the convective dispersion equation. Based on the link between angiogenesis and cancer growth, this method is evaluated for localization of prostate cancer by comparison with histology results following radical prostatectomy. Without need for an arterial input function, MR dispersion imaging enables the simultaneous generation of dispersion and permeability maps. Promising preliminary results in 7 patients are reported.

Shiyang Wang¹, Yahui Peng¹, Milica Medved¹, Ambereen Yousuf¹, Marko Ivancevic², Ibrahim Karademir¹, Yulei Jiang¹, Tatjana Antic³, Steffen Sammet¹, Aytek Oto¹, and Gregory S. Karczmar^1
1Radiology, University of Chicago, Chicago, IL, United States, ²MR clinical science, Philips Healthcare, Cleveland, OH, United States, ³Pathology, University of Chicago, Chicago, IL, United States

A novel, hybrid MR imaging method was implemented for prostate cancer detection. The proposed hybrid imaging acquires diffusion weighted MRI (DWI) data at three echo times (TE’s), and allows calculation of ADC and T2 as functions of TE and diffusion weighting factor (b-value), respectively. Preliminary results showed that both ADC and T2 calculated from the hybrid imaging data can help differentiate normal tissue regions and cancer foci. ADC at higher TE showed better differentiation than ADC at lower TE. The two dimensional 1/T2 map improved separation of cancer and normal voxels relative to a 1D comparison.

Mariska P. Luttje¹, Robin A. de Graaf², Catalina S. Arteaga de Castro¹, Peter R. Luijten¹, Marco van Vulpen¹, Uulke A. van der Heide³, and Dennis W.J. Klomp^1
1Imaging Division, Univerity Medical Center, Utrecht, Netherlands, ²MRRC, Yale University, New Haven, CT, United States, ³Department of Radiotherapy, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Amsterdam, Netherlands

In this study at 7T, we show the influence of polyamines in the variability of the cho+pa+cr/cit vs cho+cr/cit ratio by using spectral fitting with simulated basissets at 7T instead of the commonly used signal integration when including more than 200 MR spectra obtained from six patients diagnosed with prostate cancer. Ratios excluding the fitted polyamines resonances show a clear trend towards less spread over the voxels (tumor as well as healthy).

Durgesh Kumar Dwivedi¹, Girdhar Bora², Rajeev Kumar², Sanjay Thulkar³, Sanjay Sharma³, Siddhartha D. Gupta⁴, and Naranamangalam R. Jagannathan^1
1Department of NMR & MRI Facility, All India Institute of Medical Sciences, New Delhi, Delhi, India, ²Department of Urology, All India Institute of Medical Sciences, New Delhi, Delhi, India, ³Department of Radio-diagnosis, All India Institute of Medical Sciences, New Delhi, Delhi, India, ⁴Department of Pathology, All India Institute of Medical Sciences, New Delhi, Delhi, India

The challenge to clinicians in the management of prostate cancer (PCa) patients is the in vivo assessment of disease aggressiveness. TRUS biopsy detects the PCa and determines the Gleason score. Identification of patients with more-aggressive disease would help to prevent overtreatment of those with low-risk tumors. Our results showed the reduction of metabolite ratios [Cit/(Cho+Cr)] and ADC values with the increase of Gleason score. The present study indicates that MRSI and DWI could stratify the PCa disease aggressiveness non-invasively.

Thiele Kobus¹, Jeroen Van der Laak², Caroline Bruggink¹, Christina Hulsbergen-Van de Kaa², Tom W.J. Scheenen¹, and Arend Heerschap^1
1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands, ²Pathology, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands

Variations in the signal intensity of citrate and other metabolites in ¹H MRSI of the prostate may be caused by changes in luminal volume. This was investigated for cancer containing prostates by correlating signal intensities with morphological features of digitally segmented histopathological slices. A significant relation was found between the Cho+Spm+Cr/Cit ratio and the %area-of-nuclei / %-area-of-lumen, obtained from HE stained slices of prostatectomy samples. This study indicates that changes in the signal of Cit (and possibly of other metabolites) in PCa result from morphological alterations, rather than changes in metabolism.

Sophie F. Riches¹, Geoffrey S. Payne¹, Nandita M. deSouza¹, Scott Morgan², David Dearnaley³, Veronica A. Morgan¹, Sharon L. Giles¹, and Mike Partridge^4
1CR-UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom, ²Division of Radiation Oncology, University of Ottawa, Ottawa, Ontario, Canada, ³Division of Radiotherapy & Imaging, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom, ⁴Gray Institute for Radiation Oncology and Biology,Department of Oncology, University of Oxford, Oxford, Oxfordshire, United Kingdom

The use of a boosted radiation dose to a tumour nodule within the prostate is limited by poor accuracy for tumour localisation on morphological imaging; functional imaging offers more accurate delineation of the dominant intraprostatic lesion. This study uses a model that combines multifunctional MR parameters to define an intraprostatic lesion and plans an 84 Gy radiation boost to functional imaging-defined tumour with IMRT. Compared to a standard clinical treatment of 72 Gy applied uniformly across the prostate, a focal boost resulted in a greater therapeutic ratio, with potentially greater tumour control and fewer side-effects from the treatment.