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Multi-parametric MRI of Prostate Cancer: Assessment of Spectroscopy, Diffusion, Dynamic Contrast and Relaxometry for Active Surveillance and Staging / Ioannis Papadopoulos

Swansea University Author: Ioannis Papadopoulos

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DOI (Published version): 10.23889/Suthesis.51146

Abstract

Magnetic Resonance Imaging (MRI) was first applied back in the 1970’s and is a medical imaging technique for anatomical and physiological processes of the body. It is characterized by high sensitivity and distinctive diagnostic ability on soft tis-sues. A variety of pulse sequences with different char...

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Published: 2018
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
URI: https://cronfa.swan.ac.uk/Record/cronfa51146
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fullrecord <?xml version="1.0"?><rfc1807><datestamp>2019-07-22T14:23:02.9515779</datestamp><bib-version>v2</bib-version><id>51146</id><entry>2019-07-19</entry><title>Multi-parametric MRI of Prostate Cancer: Assessment of Spectroscopy, Di&#xFB00;usion, Dynamic Contrast and Relaxometry for Active Surveillance and Staging</title><swanseaauthors><author><sid>5570b0b6f09930e37ed5f31c5c49c50d</sid><ORCID>NULL</ORCID><firstname>Ioannis</firstname><surname>Papadopoulos</surname><name>Ioannis Papadopoulos</name><active>true</active><ethesisStudent>true</ethesisStudent></author></swanseaauthors><date>2019-07-19</date><abstract>Magnetic Resonance Imaging (MRI) was &#xFB01;rst applied back in the 1970&#x2019;s and is a medical imaging technique for anatomical and physiological processes of the body. It is characterized by high sensitivity and distinctive diagnostic ability on soft tis-sues. A variety of pulse sequences with di&#xFB00;erent characteristics are available for the assessment and subsequent therapeutic approaches to prostate cancer. Advanced MR techniques such as Di&#xFB00;usion Weighted Imaging (DWI), Dynamic Contrast Enhanced imaging (DCE), MR Spectroscopy (MRS) and T2 Relaxometry (R2) can be applied along with conventional T2-weighted (T2w) imaging, called multiparametric MRI (mp-MRI), to add useful clinical value. However, MRI&#x2019;s low speci&#xFB01;city can make tumour detection di&#xFB03;cult or impossible. Moreover, not every technique is appropriate for low-grade low-volume prostate cancer evaluation and thus some have been excluded from several studies and clinical protocols, the optimization of which is critical for best results.In the present study a combination of T2w and DWI was evaluated as a potential diagnostic tool for detection, staging and guided biopsies for patients with possible early-stage prostate cancer. Quanti&#xFB01;cation of the noise &#xFB02;oor in the DWI images and careful &#xFB01;tting of the data suggests that the monoexponential model provides a very good &#xFB01;t to the data and there is no evidence of non-Gaussian di&#xFB00;usion for b-values up to 1000 s/mm2. The kurtosis, a measure of non-Gaussianity, can therefore not be used as a biomarker. However, the ADC value was signi&#xFB01;cantly higher for suspicious regions than for normal regions. In addition, DWI showed high correlation with overall scores assigned according to the Prostate Imaging Reporting And Data System (PIRADS) and the results suggest that a simpli&#xFB01;ed protocol combining T2w and DWI can be cost and time e&#xFB03;cient for early-stage prostate cancer diagnostic programme, combining robust MR biomarkers that can be reliably quanti&#xFB01;ed and appear well-suited for general clinical practice.DCE MRI was also evaluated in di&#xFB00;erentiation between radiologically de&#xFB01;ned nor-mal and suspicious regions in the prostate from patients suspected of early-stage prostate cancer. The MRI signal increase following contrast agent administration was evaluated for regions de&#xFB01;ned as suspicious for malignancy or healthy, respectively. Background noise levels were calculated and signal intensities below a set threshold were excluded. The data was analysed using a phenomenological model that enables both quanti&#xFB01;cation of the signal increase due to contrast agent uptake and automatic classi&#xFB01;cation of the curve type according to previously established criteria. Curve-type classi&#xFB01;cation did not provide a clear di&#xFB00;erentiation between normal and suspicious re-gions either by visual or computer analysis. However, statistically signi&#xFB01;cant di&#xFB00;erences in the magnitude of the signal increase for normal and suspicious regions were observed. The results strengthen evidence that DCE MRI has limited value in the assessment of early stage, small volume prostate cancer in mp-MRI and that curve-type classi&#xFB01;cation is an unreliable technique for di&#xFB00;erentiation of normal and suspicious prostatic tissue.MRS scores did not signi&#xFB01;cantly correlate with overall PIRADS scores and added no clinical value compared to an mp-MRI protocol without MRS. In this study several post-processing steps were used to evaluate the acquired clinical spectra without the use of endorectal coil. The post-processing steps, especially baseline correction, a&#xFB00;ected the signals heavily. Two di&#xFB00;erent approaches were used for peak integrations but the noisy spectra made their identi&#xFB01;cation ambiguous. MRS was removed from our mp-MRI protocol.In view of signi&#xFB01;cant current interest in quantitative MRI and considering the value of T2w imaging as mainstay in the diagnosis of disease, R2 mapping was investigated as a potential addition to the protocol. To this end, di&#xFB00;erent R2 mapping protocols were tested on contrast phantoms and a small number of volunteers and patients. Although promising, R2 mapping was not incorporated in the current clinical mp-MRI protocol due to a lack of a standardized parametrization and di&#xFB00;erences observed between di&#xFB00;erent protocols, which require further investigation and the development of optimal, standardized protocol.</abstract><type>E-Thesis</type><journal/><publisher/><keywords/><publishedDay>31</publishedDay><publishedMonth>12</publishedMonth><publishedYear>2018</publishedYear><publishedDate>2018-12-31</publishedDate><doi>10.23889/Suthesis.51146</doi><url/><notes>Due to Embargo and/or Third Party Copyright restrictions, this thesis is not available via this service.</notes><college>COLLEGE NANME</college><department>Medicine</department><CollegeCode>COLLEGE CODE</CollegeCode><institution>Swansea University</institution><degreelevel>Doctoral</degreelevel><degreename>Ph.D</degreename><apcterm/><lastEdited>2019-07-22T14:23:02.9515779</lastEdited><Created>2019-07-19T16:22:27.4386092</Created><path><level id="1">Faculty of Medicine, Health and Life Sciences</level><level id="2">Swansea University Medical School - Medicine</level></path><authors><author><firstname>Ioannis</firstname><surname>Papadopoulos</surname><orcid>NULL</orcid><order>1</order></author></authors><documents/><OutputDurs/></rfc1807>
spelling 2019-07-22T14:23:02.9515779 v2 51146 2019-07-19 Multi-parametric MRI of Prostate Cancer: Assessment of Spectroscopy, Diffusion, Dynamic Contrast and Relaxometry for Active Surveillance and Staging 5570b0b6f09930e37ed5f31c5c49c50d NULL Ioannis Papadopoulos Ioannis Papadopoulos true true 2019-07-19 Magnetic Resonance Imaging (MRI) was first applied back in the 1970’s and is a medical imaging technique for anatomical and physiological processes of the body. It is characterized by high sensitivity and distinctive diagnostic ability on soft tis-sues. A variety of pulse sequences with different characteristics are available for the assessment and subsequent therapeutic approaches to prostate cancer. Advanced MR techniques such as Diffusion Weighted Imaging (DWI), Dynamic Contrast Enhanced imaging (DCE), MR Spectroscopy (MRS) and T2 Relaxometry (R2) can be applied along with conventional T2-weighted (T2w) imaging, called multiparametric MRI (mp-MRI), to add useful clinical value. However, MRI’s low specificity can make tumour detection difficult or impossible. Moreover, not every technique is appropriate for low-grade low-volume prostate cancer evaluation and thus some have been excluded from several studies and clinical protocols, the optimization of which is critical for best results.In the present study a combination of T2w and DWI was evaluated as a potential diagnostic tool for detection, staging and guided biopsies for patients with possible early-stage prostate cancer. Quantification of the noise floor in the DWI images and careful fitting of the data suggests that the monoexponential model provides a very good fit to the data and there is no evidence of non-Gaussian diffusion for b-values up to 1000 s/mm2. The kurtosis, a measure of non-Gaussianity, can therefore not be used as a biomarker. However, the ADC value was significantly higher for suspicious regions than for normal regions. In addition, DWI showed high correlation with overall scores assigned according to the Prostate Imaging Reporting And Data System (PIRADS) and the results suggest that a simplified protocol combining T2w and DWI can be cost and time efficient for early-stage prostate cancer diagnostic programme, combining robust MR biomarkers that can be reliably quantified and appear well-suited for general clinical practice.DCE MRI was also evaluated in differentiation between radiologically defined nor-mal and suspicious regions in the prostate from patients suspected of early-stage prostate cancer. The MRI signal increase following contrast agent administration was evaluated for regions defined as suspicious for malignancy or healthy, respectively. Background noise levels were calculated and signal intensities below a set threshold were excluded. The data was analysed using a phenomenological model that enables both quantification of the signal increase due to contrast agent uptake and automatic classification of the curve type according to previously established criteria. Curve-type classification did not provide a clear differentiation between normal and suspicious re-gions either by visual or computer analysis. However, statistically significant differences in the magnitude of the signal increase for normal and suspicious regions were observed. The results strengthen evidence that DCE MRI has limited value in the assessment of early stage, small volume prostate cancer in mp-MRI and that curve-type classification is an unreliable technique for differentiation of normal and suspicious prostatic tissue.MRS scores did not significantly correlate with overall PIRADS scores and added no clinical value compared to an mp-MRI protocol without MRS. In this study several post-processing steps were used to evaluate the acquired clinical spectra without the use of endorectal coil. The post-processing steps, especially baseline correction, affected the signals heavily. Two different approaches were used for peak integrations but the noisy spectra made their identification ambiguous. MRS was removed from our mp-MRI protocol.In view of significant current interest in quantitative MRI and considering the value of T2w imaging as mainstay in the diagnosis of disease, R2 mapping was investigated as a potential addition to the protocol. To this end, different R2 mapping protocols were tested on contrast phantoms and a small number of volunteers and patients. Although promising, R2 mapping was not incorporated in the current clinical mp-MRI protocol due to a lack of a standardized parametrization and differences observed between different protocols, which require further investigation and the development of optimal, standardized protocol. E-Thesis 31 12 2018 2018-12-31 10.23889/Suthesis.51146 Due to Embargo and/or Third Party Copyright restrictions, this thesis is not available via this service. COLLEGE NANME Medicine COLLEGE CODE Swansea University Doctoral Ph.D 2019-07-22T14:23:02.9515779 2019-07-19T16:22:27.4386092 Faculty of Medicine, Health and Life Sciences Swansea University Medical School - Medicine Ioannis Papadopoulos NULL 1
title Multi-parametric MRI of Prostate Cancer: Assessment of Spectroscopy, Diffusion, Dynamic Contrast and Relaxometry for Active Surveillance and Staging
spellingShingle Multi-parametric MRI of Prostate Cancer: Assessment of Spectroscopy, Diffusion, Dynamic Contrast and Relaxometry for Active Surveillance and Staging
Ioannis Papadopoulos
title_short Multi-parametric MRI of Prostate Cancer: Assessment of Spectroscopy, Diffusion, Dynamic Contrast and Relaxometry for Active Surveillance and Staging
title_full Multi-parametric MRI of Prostate Cancer: Assessment of Spectroscopy, Diffusion, Dynamic Contrast and Relaxometry for Active Surveillance and Staging
title_fullStr Multi-parametric MRI of Prostate Cancer: Assessment of Spectroscopy, Diffusion, Dynamic Contrast and Relaxometry for Active Surveillance and Staging
title_full_unstemmed Multi-parametric MRI of Prostate Cancer: Assessment of Spectroscopy, Diffusion, Dynamic Contrast and Relaxometry for Active Surveillance and Staging
title_sort Multi-parametric MRI of Prostate Cancer: Assessment of Spectroscopy, Diffusion, Dynamic Contrast and Relaxometry for Active Surveillance and Staging
author_id_str_mv 5570b0b6f09930e37ed5f31c5c49c50d
author_id_fullname_str_mv 5570b0b6f09930e37ed5f31c5c49c50d_***_Ioannis Papadopoulos
author Ioannis Papadopoulos
author2 Ioannis Papadopoulos
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publishDate 2018
institution Swansea University
doi_str_mv 10.23889/Suthesis.51146
college_str Faculty of Medicine, Health and Life Sciences
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hierarchy_top_id facultyofmedicinehealthandlifesciences
hierarchy_top_title Faculty of Medicine, Health and Life Sciences
hierarchy_parent_id facultyofmedicinehealthandlifesciences
hierarchy_parent_title Faculty of Medicine, Health and Life Sciences
department_str Swansea University Medical School - Medicine{{{_:::_}}}Faculty of Medicine, Health and Life Sciences{{{_:::_}}}Swansea University Medical School - Medicine
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description Magnetic Resonance Imaging (MRI) was first applied back in the 1970’s and is a medical imaging technique for anatomical and physiological processes of the body. It is characterized by high sensitivity and distinctive diagnostic ability on soft tis-sues. A variety of pulse sequences with different characteristics are available for the assessment and subsequent therapeutic approaches to prostate cancer. Advanced MR techniques such as Diffusion Weighted Imaging (DWI), Dynamic Contrast Enhanced imaging (DCE), MR Spectroscopy (MRS) and T2 Relaxometry (R2) can be applied along with conventional T2-weighted (T2w) imaging, called multiparametric MRI (mp-MRI), to add useful clinical value. However, MRI’s low specificity can make tumour detection difficult or impossible. Moreover, not every technique is appropriate for low-grade low-volume prostate cancer evaluation and thus some have been excluded from several studies and clinical protocols, the optimization of which is critical for best results.In the present study a combination of T2w and DWI was evaluated as a potential diagnostic tool for detection, staging and guided biopsies for patients with possible early-stage prostate cancer. Quantification of the noise floor in the DWI images and careful fitting of the data suggests that the monoexponential model provides a very good fit to the data and there is no evidence of non-Gaussian diffusion for b-values up to 1000 s/mm2. The kurtosis, a measure of non-Gaussianity, can therefore not be used as a biomarker. However, the ADC value was significantly higher for suspicious regions than for normal regions. In addition, DWI showed high correlation with overall scores assigned according to the Prostate Imaging Reporting And Data System (PIRADS) and the results suggest that a simplified protocol combining T2w and DWI can be cost and time efficient for early-stage prostate cancer diagnostic programme, combining robust MR biomarkers that can be reliably quantified and appear well-suited for general clinical practice.DCE MRI was also evaluated in differentiation between radiologically defined nor-mal and suspicious regions in the prostate from patients suspected of early-stage prostate cancer. The MRI signal increase following contrast agent administration was evaluated for regions defined as suspicious for malignancy or healthy, respectively. Background noise levels were calculated and signal intensities below a set threshold were excluded. The data was analysed using a phenomenological model that enables both quantification of the signal increase due to contrast agent uptake and automatic classification of the curve type according to previously established criteria. Curve-type classification did not provide a clear differentiation between normal and suspicious re-gions either by visual or computer analysis. However, statistically significant differences in the magnitude of the signal increase for normal and suspicious regions were observed. The results strengthen evidence that DCE MRI has limited value in the assessment of early stage, small volume prostate cancer in mp-MRI and that curve-type classification is an unreliable technique for differentiation of normal and suspicious prostatic tissue.MRS scores did not significantly correlate with overall PIRADS scores and added no clinical value compared to an mp-MRI protocol without MRS. In this study several post-processing steps were used to evaluate the acquired clinical spectra without the use of endorectal coil. The post-processing steps, especially baseline correction, affected the signals heavily. Two different approaches were used for peak integrations but the noisy spectra made their identification ambiguous. MRS was removed from our mp-MRI protocol.In view of significant current interest in quantitative MRI and considering the value of T2w imaging as mainstay in the diagnosis of disease, R2 mapping was investigated as a potential addition to the protocol. To this end, different R2 mapping protocols were tested on contrast phantoms and a small number of volunteers and patients. Although promising, R2 mapping was not incorporated in the current clinical mp-MRI protocol due to a lack of a standardized parametrization and differences observed between different protocols, which require further investigation and the development of optimal, standardized protocol.
published_date 2018-12-31T04:02:55Z
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