A Semi-parametric Technique for the Quantitative Analysis of Dynamic Contrast-enhanced MR Images Based on Bayesian P-splines

Dynamic Contrast-enhanced Magnetic Resonance Imaging (DCE-MRI) is an important tool for detecting subtle kinetic changes in cancerous tissue. Quantitative analysis of DCE-MRI typically involves the convolution of an arterial input function (AIF) with a nonlinear pharmacokinetic model of the contrast agent concentration. Parameters of the kinetic model are biologically meaningful, but the optimization of the non-linear model has significant computational issues. In practice, convergence of the optimization algorithm is not guaranteed and the accuracy of the model fitting may be compromised. To overcome this problems, this paper proposes a semi-parametric penalized spline smoothing approach, with which the AIF is convolved with a set of B-splines to produce a design matrix using locally adaptive smoothing parameters based on Bayesian penalized spline models (P-splines). It has been shown that kinetic parameter estimation can be obtained from the resulting deconvolved response function, which also includes the onset of contrast enhancement. Detailed validation of the method, both with simulated and in vivo data, is provided

Bone imaging in prostate cancer: the evolving roles of nuclear medicine and radiology

The bone scan continues to be recommended for both the staging and therapy response assessment of skeletal metastases from prostate cancer. However, it is widely recognised that bone scans have limited sensitivity for disease detection and is both insensitive and non-specific for determining treatment response, at an early enough time point to be clinically useful. We, therefore, review the evolving roles of nuclear medicine and radiology for this application. We have reviewed the published literature reporting recent developments in imaging bone metastases in prostate cancer, and provide a balanced synopsis of the state of the art. The development of single-photon emission computed tomography combined with computed tomography has improved detection sensitivity and specificity but has not yet been shown to lead to improvements in monitoring therapy. A number of bone-specific and tumour-specific tracers for positron emission tomography/computed tomography (PET/CT) are now available for advanced prostate cancer that show promise in both clinical settings. At the same time, the development of whole-body magnetic resonance imaging (WB-MRI) that incorporates diffusion-weighted imaging also offers significant improvements for detection and therapy response assessment. There are emerging data showing comparative SPECT/CT, PET/CT, and WB-MRI test performance for disease detection, but no compelling data on the usefulness of these technologies in response assessment have yet emerged

Fast Magnetic Resonance Imaging as a Viable Method for Directing the Prostate Cancer Diagnostic Pathway

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Factors Influencing Variability in the Performance of Multiparametric Magnetic Resonance Imaging in Detecting Clinically Significant Prostate Cancer: A Systematic Literature Review

CONTEXT: There is a lack of comprehensive data regarding the factors that influence the diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI) to detect and localize clinically significant prostate cancer (csPCa). OBJECTIVE: To systematically review the current literature assessing the factors influencing the variability of mpMRI performance in csPCa diagnosis. EVIDENCE ACQUISITION: A computerized bibliographic search of Medline/PubMed database was performed for all studies assessing magnetic field strength, use of an endorectal coil, assessment system used by radiologists and inter-reader variability, experience of radiologists and urologists, use of a contrast agent, and use of computer-aided diagnosis (CAD) tools in relation to mpMRI diagnostic accuracy. EVIDENCE SYNTHESIS: A total of 77 articles were included. Both radiologists' reading experience and urologists'/radiologists' biopsy experience were the main factors that influenced diagnostic accuracy. Therefore, it is mandatory to indicate the experience of the interpreting radiologists and biopsy-performing urologists to support the reliability of the findings. The most recent Prostate Imaging Reporting and Data System (PI-RADS) guidelines are recommended for use as the main assessment system for csPCa, given the simplified and standardized approach as well as its particular added value for less experienced radiologists. Biparametric MRI had similar accuracy to mpMRI; however, biparametric MRI performed better with experienced readers. The limited data available suggest that the combination of CAD and radiologist readings may influence diagnostic accuracy positively. CONCLUSIONS: Multiple factors affect the accuracy of mpMRI and MRI-targeted biopsy to detect and localize csPCa. The high heterogeneity across the studies underlines the need to define the experience of radiologists and urologists, implement quality control, and adhere to the most recent PI-RADS assessment guidelines. Further research is needed to clarify which factors impact the accuracy of the MRI pathway and how. PATIENT SUMMARY: We systematically reported the factors influencing the accuracy of multiparametric magnetic resonance imaging (mpMRI) in detecting clinically significant prostate cancer (csPCa). These factors are significantly related to each other, with the experience of the radiologists being the dominating factor. In order to deliver the benefits of mpMRI to diagnose csPCa, it is necessary to develop expertise for both radiologists and urologists, implement quality control, and adhere to the most recent Prostate Imaging Reporting and Data System assessment guidelines

Proton magnetic resonance spectroscopy in oncology: the fingerprints of cancer?

Abnormal metabolism is a key tumor hallmark. Proton magnetic resonance spectroscopy (1H-MRS) allows measurement of metabolite concentration that can be utilized to characterize tumor metabolic changes. 1H-MRS measurements of specific metabolites have been implemented in the clinic. This article performs a systematic review of image acquisition and interpretation of 1H-MRS for cancer evaluation, evaluates its strengths and limitations, and correlates metabolite peaks at 1H-MRS with diagnostic and prognostic parameters of cancer in different tumor types

Head-to-head Comparison of Transrectal Ultrasound-guided Prostate Biopsy Versus Multiparametric Prostate Resonance Imaging with Subsequent Magnetic Resonance-guided Biopsy in Biopsy-naive Men with Elevated Prostate-specific Antigen: A Large Prospective Multicenter Clinical Study

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Diffusionâ weighted imaging outside the brain: Consensus statement from an ISMRMâ sponsored workshop

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134160/1/jmri25196_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134160/2/jmri25196.pd

Reporting Magnetic Resonance Imaging in Men on Active Surveillance for Prostate Cancer : The PRECISE Recommendations-A Report of a European School of Oncology Task Force

Background: Published data on prostate magnetic resonance imaging (MRI) during follow-up of men on active surveillance are lacking. Current guidelines for prostate MRI reporting concentrate on prostate cancer (PCa) detection and staging. A standardised approach to prostate MRI reporting for active surveillance will facilitate the robust collection of evidence in this newly developing area. Objective: To develop preliminary recommendations for reporting of individual MRI studies in men on active surveillance and for researchers reporting the outcomes of cohorts of men having MRI on active surveillance. Design, setting, and participants: The RAND/UCLA Appropriateness Method was used. Experts in urology, radiology, and radiation oncology developed a set of 394 statements relevant to prostate MRI reporting in men on active surveillance for PCa. Each statement was scored for agreement on a 9-point scale by each panellist prior to a panel meeting. Each statement was discussed and rescored at the meeting. Outcome measurements and statistical analysis: Measures of agreement and consensus were calculated for each statement. The most important statements, derived from both group discussion and scores of agreement and consensus, were used to create the Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) checklist and case report form. Results and limitations: Key recommendations include reporting the index lesion size using absolute values at baseline and at each subsequent MRI. Radiologists should assess the likelihood of true change over time (ie, change in size or change in lesion characteristics on one or more sequences) on a 1-5 scale. A checklist of items for reporting a cohort of men on active surveillance was developed. These items were developed based on expert consensus in many areas in which data are lacking, and they are expected to develop and change as evidence is accrued. Conclusions: The PRECISE recommendations are designed to facilitate the development of a robust evidence database for documenting changes in prostateMRI findings over time ofmen on active surveillance. If used, they will facilitate data collection to distinguish-measurement error and natural variability in MRI appearances from true radiologic progression. Patient summary: Few published reports are available on how to use and interpret magnetic resonance imaging for men on active surveillance for prostate cancer. The PRECISE panel recommends that data should be collected in a standardised manner so that natural variation in the appearance and measurement of cancer over time can be distinguished from changes indicating significant tumour progression. (C) 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.Peer reviewe

Comparison of whole-body MRI, CT, and bone scintigraphy for response evaluation of cancer therapeutics in metastatic breast cancer to bone

In participants receiving systemic anticancer therapy for bone-only metastatic breast cancer, whole-body MRI enabled identification of progressive disease earlier than whole-body CT and bone scintigraphy. Background CT and bone scintigraphy have limitations in evaluating systemic anticancer therapy (SACT) response in bone metastases from metastatic breast cancer (MBC). Purpose To evaluate whether whole-body MRI enables identification of progressive disease (PD) earlier than CT and bone scintigraphy in bone-only MBC. Materials and Methods This prospective study evaluated participants with bone-only MBC between May 2016 and January 2019 (ClinicalTrials.gov identifier: NCT03266744). Participants were enrolled at initiation of first or subsequent SACT based on standard CT and bone scintigraphy imaging. Baseline whole-body MRI was performed within 2 weeks of entry; those with extraosseous disease were excluded. CT and whole-body MRI were performed every 12 weeks until definitive PD was evident with one or both modalities. In case of PD, bone scintigraphy was used to assess for bone disease progression. Radiologists independently interpreted images from CT, whole-body MRI, or bone scintigraphy and were blinded to results with the other modalities. Systematic differences in performance between modalities were analyzed by using the McNemar test. Results Forty-five participants (mean age, 60 years ± 13 [standard deviation]; all women) were evaluated. Median time on study was 36 weeks (range, 1–120 weeks). Two participants were excluded because of unequivocal evidence of liver metastases at baseline whole-body MRI, two participants were excluded because they had clinical progression before imaging showed PD, and one participant was lost to follow-up. Of the 33 participants with PD at imaging, 67% (22 participants) had PD evident at whole-body MRI only and 33% (11 participants) had PD at CT and whole-body MRI concurrently; none had PD at CT only (P < .001, McNemar test). There was only slight agreement between whole-body MRI and CT (Cohen κ, 0.15). PD at bone scintigraphy was reported in 50% of participants (13 of 26) with bone progression at CT and/or whole-body MRI (P < .001, McNemar test). Conclusion Whole-body MRI enabled identification of progressive disease before CT in most participants with bone-only metastatic breast cancer. Progressive disease at bone scintigraphy was evident in only half of participants with bone progression at whole-body MRI

How clinical imaging can assess cancer biology.

Human cancers represent complex structures, which display substantial inter- and intratumor heterogeneity in their genetic expression and phenotypic features. However, cancers usually exhibit characteristic structural, physiologic, and molecular features and display specific biological capabilities named hallmarks. Many of these tumor traits are imageable through different imaging techniques. Imaging is able to spatially map key cancer features and tumor heterogeneity improving tumor diagnosis, characterization, and management. This paper aims to summarize the current and emerging applications of imaging in tumor biology assessment