Incorporating endorectal MR elastography into multi‐parametric MRI for prostate cancer imaging: Initial feasibility in volunteers

Arani, Arvin; Rosa, Michael Da; Ramsay, Elizabeth; Plewes, Don B.; Haider, Masoom A.; Chopra, Rajiv

doi:10.1002/jmri.24028

Cited by 30 publications

(28 citation statements)

References 33 publications

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“…Therefore, there are limitations on how these results can be translated to in-vivo applications. The fixation process may explain why the PZ appears stiffer (because the periphery of the prostate is closer to the chemical solution) than the CG in this work and others (7), while the opposite is the case in in-vivo tissue (19). Another consequence of the fixation process is the changed stiffness baseline for each case, depending on the time the gland was left in the formaldehyde solution (see Figure 8).…”

Section: General Observationsmentioning

confidence: 71%

MR elastography and diffusion‐weighted imaging of ex vivo prostate cancer: quantitative comparison to histopathology

et al. 2014

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Purpose-1) to develop a Magnetic Resonance Elastography (MRE) system for imaging of the ex-vivo human prostate, 2) to assess the diagnostic power of mono-frequency and multi-frequency MRE and diffusion weighted imaging (DWI) alone and combined as correlated with histopathology in a patient study.Materials and Methods-An electromagnetic driver was designed specifically for MRE studies in small-bore MR scanners. Ex-vivo prostate specimens (post-fixation) of fourteen patients who underwent radical prostatectomy were imaged with MRE at 7 T (nine cases had DWI). In six patients, the MRE examination was performed at three frequencies (600, 800, 1000 Hz) to extract the power-law exponent Gamma. The images were registered to wholemount pathology slides marked with the Gleason score. The areas under the Receiver-Operator-Characteristic curves (AUC) were calculated.Results-The methods were validated in a phantom study and demonstrated that (i) the driver does not interfere with the acquisition process, (ii) the driver can generate amplitudes greater than 100 μm for frequencies <1kHz. In the quantitative study, cancerous tissue with Gleason score at least 3+3 was distinguished from normal tissue in the peripheral zone with an average AUC of 0.75 (G d ), 0.75 (G l ), 0.70 (Gamma-G d ), 0.68 (ADC), and 0.82 (G d +G l +ADC). The differentiation between PZ and CG was modest for G d (p<0.07), G l (p<0.06) but not significant for Gamma (p<0.2). A correlation of 0.4 kPa/h was found between fixation time of the prostate specimen to the stiffness of the tissue which could affect the diagnostic power results.Conclusion-DWI and MRE may provide complementary information; in fact MRE performed better than ADC in distinguishing normal from cancerous tissue in some cases. Multi-frequency (Gamma) analysis did not appear to improve the results. However, in light of effect of tissue fixation, the clinical implication of our results may be inconclusive and more experiments are needed.

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Section: General Observationsmentioning

confidence: 71%

MR elastography and diffusion‐weighted imaging of ex vivo prostate cancer: quantitative comparison to histopathology

et al. 2014

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“…Other emerging indications for abdominal elastography include characterization of focal liver lesions [6, 7, 9] and evaluation of other solid organs [84–86]. …”

Section: Future Directionsmentioning

confidence: 99%

Ultrasound Elastography and MR Elastography for Assessing Liver Fibrosis: Part 2, Diagnostic Performance, Confounders, and Future Directions

Tang

Cloutier

Szeverenyi

et al. 2015

American Journal of Roentgenology

171

112

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OBJECTIVE-The purpose of the article is to review the diagnostic performance of ultrasound and MR elastography techniques for detection and staging of liver fibrosis, the main current clinical applications of elastography in the abdomen.CONCLUSION-Technical and instrument-related factors and biologic and patient-related factors may constitute potential confounders of stiffness measurements for assessment of liver fibrosis. Future developments may expand the scope of elastography for monitoring liver fibrosis and predict complications of chronic liver disease. Keywords elasticity; elastography; liver fibrosis; MR elastography (MRE); MRI; ultrasound; viscosity In abdominal imaging, liver stiffness estimated by elastography techniques may be used as a quantitative imaging biomarker for detection, staging, and monitoring of liver fibrosis [1][2][3]. Liver stiffness is used to evaluate the severity of the underlying chronic liver disease, guide treatment decision, assess disease outcome, and evaluate response to therapy [4].In this second article of a two-part series [5], we will discuss the clinical applications in the liver. We will focus on diagnostic performance of ultrasound elastography and MR Address correspondence to C. B. Sirlin (csirlin@ucsd.edu).. Technologies developed by the team of G. Cloutier were licensed to Rheolution, Inc., and Acist Medical Systems. HHS Public Access Author Manuscript Author ManuscriptAuthor ManuscriptAuthor Manuscript elastography techniques for detection, staging, and monitoring of liver fibrosis, the main current clinical applications of elastography in the abdomen. We will discuss potential confounders of stiffness measurements for assessment of liver fibrosis, which include technical and instrument-related factors (location and depth of measurements, wave frequencies, and device dependencies) and biologic and patient-related factors (concomitant hepatic steatosis, inflammation, cholestasis; breathing; right heart failure and hepatic venous congestion; and fasting vs postprandial state). Finally, we will briefly discuss future directions and technical innovations in this field of research.As will be shown in this article, elastography techniques integrated to clinical ultrasound and MR systems now provide the capability to examine by imaging what once could be examined only by direct palpation, which is likely to open new opportunities to noninvasively diagnose disease, guide management, and improve outcomes. Key Learning PointsFirst, the main current clinical indications for abdominal elastography techniques are detection and staging of liver fibrosis. In general, elastography techniques provide good-toexcellent diagnostic accuracy for the detection of advanced fibrosis but have more modest performance for detection of early or mild fibrosis. Most studies to date have been in adults; performance characteristics in children are less well known. Research is needed to better understand the performance of elastography for monitoring longitudinal changes in fibrosis. Emerg...

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“…MRE has been shown to be of clinical value in MRI for its ability to detect tissue abnormalities in organs such as the liver [66], brain [67] and breast [68–70]. More recently, researchers have also focused on the development of MRE methods to detect prostate cancer [71–73]. The resulting wave fields are imaged using a motion-sensitized MRI pulse sequence.…”

Section: Mr Image Acquisitionsmentioning

confidence: 99%

Computer-aided Detection of Prostate Cancer with MRI

et al. 2016

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One in six men will develop prostate cancer in his life time. Early detection and accurate diagnosis of the disease can improve cancer survival and reduce treatment costs. Recently, imaging of prostate cancer has greatly advanced since the introduction of multi-parametric magnetic resonance imaging (mp-MRI). Mp-MRI consists of T2-weighted sequences combined with functional sequences including dynamic contrast-enhanced MRI, diffusion-weighted MRI, and MR spectroscopy imaging. Due to the big data and variations in imaging sequences, detection can be affected by multiple factors such as observer variability and visibility and complexity of the lesions. In order to improve quantitative assessment of the disease, various computer-aided detection systems have been designed to help radiologists in their clinical practice. This review paper presents an overview of literatures on computer-aided detection of prostate cancer with mp-MRI, which include the technology and its applications. The aim of the survey is threefold: an introduction for those new to the field, an overview for those working in the field, and a reference for those searching for literature on a specific application.

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Incorporating endorectal MR elastography into multi‐parametric MRI for prostate cancer imaging: Initial feasibility in volunteers

Abstract: The results of this study motivate further investigation of eMRE in prostate cancer patients to help determine if there is an added value of integrating eMRE into existing multi-parametric prostate MRI exams.

Cited by 30 publications

References 33 publications

MR elastography and diffusion‐weighted imaging of ex vivo prostate cancer: quantitative comparison to histopathology

MR elastography and diffusion‐weighted imaging of ex vivo prostate cancer: quantitative comparison to histopathology

Ultrasound Elastography and MR Elastography for Assessing Liver Fibrosis: Part 2, Diagnostic Performance, Confounders, and Future Directions

Computer-aided Detection of Prostate Cancer with MRI

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