Multidisciplinary Functional MR Imaging for Prostate Cancer

Various functional magnetic resonance (MR) imaging techniques are used for evaluating prostate cancer including diffusion-weighted imaging, dynamic contrast-enhanced MR imaging, and MR spectroscopy. These techniques provide unique information that is helpful to differentiate prostate cancer from non-cancerous tissue and have been proven to improve the diagnostic performance of MRI not only for cancer detection, but also for staging, post-treatment monitoring, and guiding prostate biopsies. However, each functional MR imaging technique also has inherent challenges. Therefore, in order to make accurate diagnoses, it is important to comprehensively understand their advantages and limitations, histologic background related with image findings, and their clinical relevance for evaluating prostate cancer. This article will review the basic principles and clinical significance of functional MR imaging for evaluating prostate cancer

Multiparametric MR imaging for detection of clinically significant prostate cancer: a validation cohort study with transperineal template prostate mapping as the reference standard.

PURPOSE: To evaluate the diagnostic performance of multiparametric (MP) magnetic resonance (MR) imaging for prostate cancer detection by using transperineal template prostate mapping (TTPM) biopsies as the reference standard and to determine the potential ability of MP MR imaging to identify clinically significant prostate cancer. MATERIALS AND METHODS: Institutional review board exemption was granted by the local research ethics committee for this retrospective study. Included were 64 men (mean age, 62 years [range, 40-76]; mean prostate-specific antigen, 8.2 ng/mL [8.2 μg/L] [range, 2.1-43 ng/mL]), 51 with biopsy-proved cancer and 13 suspected of having clinically significant cancer that was biopsy negative or without prior biopsy. MP MR imaging included T2-weighted, dynamic contrast-enhanced and diffusion-weighted imaging (1.5 T, pelvic phased-array coil). Three radiologists independently reviewed images and were blinded to results of biopsy. Two-by-two tables were derived by using sectors of analysis of four quadrants, two lobes, and one whole prostate. Primary target definition for clinically significant disease necessary to be present within a sector of analysis on TTPM for that sector to be deemed positive was set at Gleason score of 3+4 or more and/or cancer core length involvement of 4 mm or more. Sensitivity, negative predictive value, and negative likelihood ratio were calculated to determine ability of MP MR imaging to rule out cancer. Specificity, positive predictive value, positive likelihood ratio, accuracy (overall fraction correct), and area under receiver operating characteristic curves were also calculated. RESULTS: Twenty-eight percent (71 of 256) of sectors had clinically significant cancer by primary endpoint definition. For primary endpoint definition (≥ 4 mm and/or Gleason score ≥ 3+4), sensitivity, negative predictive value, and negative likelihood ratios were 58%-73%, 84%-89%, and 0.3-0.5, respectively. Specificity, positive predictive value, and positive likelihood ratios were 71%-84%, 49%-63%, and 2.-3.44, respectively. Area under the curve values were 0.73-0.84. CONCLUSION: Results of this study indicate that MP MR imaging has a high negative predictive value to rule out clinically significant prostate cancer and may potentially have clinical use in diagnostic pathways of men at risk

Hyperpolarized 13C-pyruvate MRI detects real-time metabolic flux in prostate cancer metastases to bone and liver: a clinical feasibility study.

BackgroundHyperpolarized (HP) 13C-pyruvate MRI is a stable-isotope molecular imaging modality that provides real-time assessment of the rate of metabolism through glycolytic pathways in human prostate cancer. Heretofore this imaging modality has been successfully utilized in prostate cancer only in localized disease. This pilot clinical study investigated the feasibility and imaging performance of HP 13C-pyruvate MR metabolic imaging in prostate cancer patients with metastases to the bone and/or viscera.MethodsSix patients who had metastatic castration-resistant prostate cancer were recruited. Carbon-13 MR examination were conducted on a clinical 3T MRI following injection of 250 mM hyperpolarized 13C-pyruvate, where pyruvate-to-lactate conversion rate (kPL) was calculated. Paired metastatic tumor biopsy was performed with histopathological and RNA-seq analyses.ResultsWe observed a high rate of glycolytic metabolism in prostate cancer metastases, with a mean kPL value of 0.020 ± 0.006 (s-1) and 0.026 ± 0.000 (s-1) in bone (N = 4) and liver (N = 2) metastases, respectively. Overall, high kPL showed concordance with biopsy-confirmed high-grade prostate cancer including neuroendocrine differentiation in one case. Interval decrease of kPL from 0.026 at baseline to 0.015 (s-1) was observed in a liver metastasis 2 months after the initiation of taxane plus platinum chemotherapy. RNA-seq found higher levels of the lactate dehydrogenase isoform A (Ldha,15.7 ± 0.7) expression relative to the dominant isoform of pyruvate dehydrogenase (Pdha1, 12.8 ± 0.9).ConclusionsHP 13C-pyruvate MRI can detect real-time glycolytic metabolism within prostate cancer metastases, and can measure changes in quantitative kPL values following treatment response at early time points. This first feasibility study supports future clinical studies of HP 13C-pyruvate MRI in the setting of advanced prostate cancer

MR-Guided Interventions for Prostate Cancer

Cataloged from PDF version of article.MR imaging is currently the most effective diagnostic imaging tool for visualizing the anatomy and pathology of the prostate gland. Currently, the practicality and cost effectiveness of transrectal ultrasound dominates image guidance for needle-based prostate interventions. Challenges to the integration of diagnostic and interventional MR imaging have included the lack of real-time feedback, the complexity of the imaging technique, and limited access to the perineum within the geometric constraints of the MR imaging scanner. Two basic strategies have been explored and clinically demonstrated in the literature: (1) coregistration of previously acquired diagnostic MR imaging to interventional TRUS or open scanner MR images, and (2) stereotactic needle interventions within conventional diagnostic scanners using careful patient positioning or the aid of simple manipulators. Currently, researchers are developing techniques that render MR imaging the method of choice for the direct guidance of many procedures. This article focuses on needle-based interventions for prostate cancer, including biopsy, brachytherapy, and thermal therapy. With rapid progress in biologic imaging of the prostate gland, the authors believe that MR imaging guidance will play an increasing role in the diagnosis and treatment of prostate cancer. © 2005 Elsevier Inc. All rights reserved

MR Spectroscopic Imaging of Peripheral Zone in Prostate Cancer Using a 3T MRI Scanner: Endorectal versus External Phased Array Coils.

Magnetic resonance spectroscopic imaging (MRSI) detects alterations in major prostate metabolites, such as citrate (Cit), creatine (Cr), and choline (Ch). We evaluated the sensitivity and accuracy of three-dimensional MRSI of prostate using an endorectal compared to an external phased array "receive" coil on a 3T MRI scanner. Eighteen patients with prostate cancer (PCa) who underwent endorectal MR imaging and proton (1H) MRSI were included in this study. Immediately after the endorectal MRSI scan, the PCa patients were scanned with the external phased array coil. The endorectal coil-detected metabolite ratio [(Ch+Cr)/Cit] was significantly higher in cancer locations (1.667 ± 0.663) compared to non-cancer locations (0.978 ± 0.420) (P < 0.001). Similarly, for the external phased array, the ratio was significantly higher in cancer locations (1.070 ± 0.525) compared to non-cancer locations (0.521 ± 0.310) (P < 0.001). The sensitivity and accuracy of cancer detection were 81% and 78% using the endorectal 'receive' coil, and 69% and 75%, respectively using the external phased array 'receive' coil

Role of multiparametric MRI in detection of prostatic lesions; of evaluation contrast enhanced MRI, diffusion weighted imaging and MR spectroscopy in malignant and benign prostatic lesions

Background: Prostate cancer is the most commonly diagnosed cancer in males and one of the leading causes of cancer-related death in men. Pretreatment assessment of prostate cancer is divided into detection, localization, and staging; accurate assessment is a prerequisite for optimal clinical management and therapy selection. The purpose of the study is to determine the diagnostic accuracy of multiparametric MRI for prostatic cancer detection using T2 weighted MR imaging, diffusion weighted imaging (DWI) and contrast enhanced MRI. To determine the use of MR spectroscopy in prostatic lesions.Methods: It is a prospective single institutional study done on 29 patients with prostate lesions and elevated PSA level. Axial, coronal and sagittal images were obtained using T1WI, T2WI and STIR sequences. Advanced sequences like Diffusion weighted images, Spectroscopy and post gadolinium T1WI were taken after the basic MRI images.Results: Study was done in 29 patients, age was ranging between 51years to 90 years, mean age is 70.7 years. On multiparametric MRI findings 45% were detected malignant lesions and 55% patients detected benign lesions. On biopsy correlation 42% of these cases turned out to be malignant and 58% as benign lesions. Detection of malignancy by T2WI imaging alone given sensitivity of 80.1% and specificity of 85.4%.By DWI alone sensitivity was 85.7% and specificity was 89.4%,on MRS sensitivity is 90.6% and specificity was 91.1%. Combined (MRI+DWI+MRS) gave sensitivity of 92.3% and specificity of 94.4% for detection of malignant prostatic lesion. Positive predictive value is 90% and negative predictive value was 88%.Conclusions: The best characterization of prostatic cancer in individual patients will most likely result from a multiparametric exam. Recent advances include additional functional and physiologic MR imaging techniques (diffusion weighted imaging, MR spectroscopy, and perfusion imaging), which allow extension of the obtainable information beyond anatomic assessment. Multiparametric MR imaging provides the highest accuracy in diagnosis and staging of prostate cancer

Multiparametric MR imaging in diagnosis of chronic prostatitis and its differentiation from prostate cancer

AbstractChronic prostatitis is a heterogeneous condition with high prevalence rate. Chronic prostatitis has overlap in clinical presentation with other prostate disorders and is one of the causes of high serum prostate specific antigen (PSA) level. Chronic prostatitis, unlike acute prostatitis, is difficult to diagnose reliably and accurately on the clinical grounds alone. Not only this, it is also challenging to differentiate chronic prostatitis from prostate cancer with imaging modalities like TRUS and conventional MR Imaging, as the findings can mimic those of prostate cancer. Even biopsy doesn't play promising role in the diagnosis of chronic prostatitis as it has limited sensitivity and specificity. As a result of this, chronic prostatitis may be misdiagnosed as a malignant condition and end up in aggressive surgical management resulting in increased morbidity. This warrants the need of reliable diagnostic tool which has ability not only to diagnose it reliably but also to differentiate it from the prostate cancer. Recently, it is suggested that multiparametric MR Imaging of the prostate could improve the diagnostic accuracy of the prostate cancer. This review is based on the critically published literature and aims to provide an overview of multiparamateric MRI techniques in the diagnosis of chronic prostatitis and its differentiation from prostate cancer

Obrazowanie morfologiczne MR i 3D spektroskopia protonowa przy użyciu cewki endorektalnej w diagnostyce raka prostaty : doświadczenia wstępne

Background: Morphological MR imaging using endorectal coil has high sensitivity but insufficient specificity in the detection of prostatic cancer. Higher specificity may be obtained by combining morphological MR with data on local metabolic disturbances in MR spectroscopy. The aim of our study was to assess the diagnostic accuracy of combined morphological MR and 3D proton spectroscopy using endorectal coil in prostate cancer detection. Material/Methods: Morphological MR and 3D proton MR spectroscopy were performed in 20 patients with suspicion of prostate cancer on the basis of DRE, TRUS and/or PSA levels, finally verified in biopsy after MR. The examinations were performed with a 1.5 T GE Signa Excite scanner using an endorectal coil. We used axial, coronal and sagittal T2 FSE, axial T1 SE and 3D PROSE (PROstate Spectroscopy and imaging Examination) sequences. The diagnostic accuracy of combined morphological and spectroscopy assessment was compared to the accuracy of morphological MR alone. Results: The specificity, PPV, and NPV of MR imaging using endorectal coil in the detection of prostatic cancer were higher in combined morphological and spectroscopic assessment compared to morphological assessment alone. Conclusions: 3D MR spectroscopy, in comparison to morphological MR imaging, provides additional data concerning metabolic disturbances in prostate cancer foci. The use of combined morphological MR and MR spectroscopy can improve the specificity of prostate cancer detection

Modalities for Imaging of Prostate Cancer

Prostate cancer is the second most common cause of cancer deaths among males in the United States. Prostate screening by digital rectal examination and prostate-specific antigen has shifted the diagnosis of prostate cancer to lower grade, organ confined disease, adding to overdetection and overtreatment of prostate cancer. The new challenge is in differentiating clinically relevant tumors from ones that may otherwise never have become evident if not for screening. The rapid evolution of imaging modalities and the synthesis of anatomic, functional, and molecular data allow for improved detection and characterization of prostate cancer. However, the appropriate use of imaging is difficult to define, as many controversial studies regarding each of the modalities and their utilities can be found in the literature. Clinical practice patterns have been slow to adopt many of these advances as a result. This review discusses the more established imaging techniques, including Ultrasonography, Magnetic Resonance Imaging, MR Spectroscopy, Computed Tomography, and Positron Emission Tomography. We also review several promising techniques on the horizon, including Dynamic Contrast-Enhanced MRI, Diffuse-Weighted Imaging, Superparamagnetic Nanoparticles, and Radionuclide Scintigraphy