John Kurhanewicz

University of California, San Francisco, San Francisco, California, United States

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Publications (263)840.19 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: External beam radiation treatment (EBRT) is a popular method for treating prostate cancer (CaP) involving destroying tumor cells with ionizing radiation. Following EBRT, biochemical failure has been linked with disease recurrence. However, there is a need for methods for evaluating early treatment related changes to allow for an early intervention in case of incomplete disease response. One method for looking at treatment evaluation is to detect changes in MRI markers on a voxel-by-voxel basis following treatment. Changes in MRI markers may be correlated with disease recurrence and complete or partial response. In order to facilitate voxel-by-voxel imaging related treatment changes, and also to evaluate morphologic changes in the gland post treatment, the pre- and post-radiated MRI must first be brought into spatial alignment via image registration. However, EBRT induces changes in the prostate volume and distortion to the internal anatomy of the prostate following radiation treatment. The internal substructures of the prostate, the central gland (CG) and peripheral zone (PZ), may respond to radiation differently, and their resulting shapes may change drastically. Biomechanical models of the prostate that have been previously proposed tend to focus on how external forces affect the surface of the prostate (not the internals), and assume that the prostate is a volume-preserving entity. In this work we present DoCD, a biomechanical model for automatically registering pre-, post-EBRT MRI with the aim of expressly modeling the (1) changes in volume, and (2) changes to the CG and PZ. DoCD was applied to a cohort of 30 patients and achieved a root mean square error of 2.994 mm, which was statistically significantly better a traditional biomechanical model which did not consider changes to the internal anatomy of the prostate (mean of 5.071 mm).
    Neurocomputing 11/2014; 144:3–12. · 2.01 Impact Factor
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    ABSTRACT: Oxidative stress has been proposed to be a unifying cause for diabetic nephropathy, and a target for novel therapies. Here we apply a new endogenous redox sensor, hyperpolarized (HP) (13)C dehydroascorbate (DHA), in conjunction with magnetic resonance imaging to noninvasively interrogate the renal redox capacity in a mouse diabetes model. The diabetic mice demonstrate early decrease in renal redox capacity, as shown by the lower in vivo HP (13)C DHA reduction to the antioxidant Vitamin C, prior to histological evidence of nephropathy. This correlates to lower tissue reduced glutathione (GSH) concentration and higher NADPH Oxidase 4 (Nox4) expression, consistent with increased superoxide generation and oxidative stress. Angiotensin converting enzyme inhibition restores the HP (13)C DHA reduction to Vitamin C with concomitant normalization of GSH concentration and Nox4 expression in the diabetic mice. HP (13)C DHA enables rapid in vivo assessment of altered redox capacity in diabetic renal injury and following successful treatment.
    Diabetes 09/2014; · 7.90 Impact Factor
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    ABSTRACT: The purpose of this study is to determine if the severity of visually-assessed image distortion is less in prostate MR apparent diffusion coefficient (ADC) maps generated from a reduced-field-of-view (rFOV) diffusion-weighted-imaging (DWI) technique than from a conventional DWI sequence (CONV) and to determine if the rFOV ADC contrast between untreated tumors and healthy-appearing tissue within subjects is as high as or better than that of the CONV sequence. Fifty patients underwent a 3 T prostate MRI with phased-array and fluid-filled endorectal coils. CONV and rFOV sequences, utilizing a 2D, echo-planar, rectangularly-selective RF pulse, were acquired using b = 600, 0 s/mm2. Distortion was visually scored 0–4 by three independent observers. Distortion scores were significantly lower with the rFOV sequence (p < 0.012, Wilcoxon Signed-Rank Test, n = 50). The difference in distortion score did not differ significantly among observers (p = 0.99, Kruskal-Wallis Rank Sum Test). For seventeen untreated patients, regions of interest to calculate contrast were selected on radiologist-identified tumor regions and healthy-appearing contralateral tissue. The rFOV sequence afforded significantly higher ADC contrast between untreated tumor and healthy tissue (44.0% versus 35.9%, p < 0.0012, paired t-test, n = 17). The rFOV sequence yielded significantly decreased rectal susceptibility artifact and provided significantly higher contrast between tumor and healthy tissue.
    Magnetic Resonance Imaging 09/2014; · 2.02 Impact Factor
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    ABSTRACT: PurposeHyperpolarized 13C magnetic resonance allows for the study of real-time metabolism in vivo, including significant hyperpolarized 13C lactate production in many tumors. Other studies have shown that aggressive and highly metastatic tumors rapidly transport lactate out of cells. Thus, the ability to not only measure the production of hyperpolarized 13C lactate but also understand its compartmentalization using diffusion-weighted MR will provide unique information for improved tumor characterization.Methods We used a bipolar, pulsed-gradient, double spin echo imaging sequence to rapidly generate diffusion-weighted images of hyperpolarized 13C metabolites. Our methodology included a simultaneously acquired B1 map to improve apparent diffusion coefficient (ADC) accuracy and a diffusion-compensated variable flip angle scheme to improve ADC precision.ResultsWe validated this sequence and methodology in hyperpolarized 13C phantoms. Next, we generated ADC maps of several hyperpolarized 13C metabolites in a normal rat, rat brain tumor, and prostate cancer mouse model using both preclinical and clinical trial-ready hardware.ConclusionADC maps of hyperpolarized 13C metabolites provide information about the localization of these molecules in the tissue microenvironment. The methodology presented here allows for further studies to investigate ADC changes due to disease state that may provide unique information about cancer aggressiveness and metastatic potential. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc.
    Magnetic Resonance in Medicine 09/2014; · 3.40 Impact Factor
  • David M Wilson, John Kurhanewicz
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    ABSTRACT: Hyperpolarization using dissolution dynamic nuclear polarization has emerged as a versatile method to dramatically improve the MR signal of low-sensitivity nuclei. This technique facilitates the study of real-time metabolism in vitro and in vivo using (13)C-enriched substrates and has been applied to numerous models of human disease. In particular, several mechanisms underlying prostate cancer have been interrogated using hyperpolarized (13)C MR spectroscopy. This review highlights key metabolic shifts seen in prostate cancer, their study by hyperpolarized (13)C MR spectroscopy, and the development of new platforms for metabolic study.
    Journal of Nuclear Medicine 08/2014; · 5.56 Impact Factor
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    ABSTRACT: Organic cation transporter 1, OCT1 (SLC22A1), is the major hepatic uptake transporter for metformin, the most prescribed antidiabetic drug. However, its endogenous role is poorly understood. Here we show that similar to metformin treatment, loss of Oct1 caused an increase in the ratio of AMP to ATP, activated the energy sensor AMP-activated kinase (AMPK), and substantially reduced triglyceride (TG) levels in livers from healthy and leptin-deficient mice. Conversely, livers of human OCT1 transgenic mice fed high-fat diets were enlarged with high TG levels. Metabolomic and isotopic uptake methods identified thiamine as a principal endogenous substrate of OCT1. Thiamine deficiency enhanced the phosphorylation of AMPK and its downstream target, acetyl-CoA carboxylase. Metformin and the biguanide analog, phenformin, competitively inhibited OCT1-mediated thiamine uptake. Acute administration of metformin to wild-type mice reduced intestinal accumulation of thiamine. These findings suggest that OCT1 plays a role in hepatic steatosis through modulation of energy status. The studies implicate OCT1 as well as metformin in thiamine disposition, suggesting an intriguing and parallel mechanism for metformin and its major hepatic transporter in metabolic function.
    Proceedings of the National Academy of Sciences 06/2014; · 9.81 Impact Factor
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    ABSTRACT: To determine the ability of multiparametric MR imaging to predict disease progression in patients with prostate cancer managed by active surveillance. Sixty-four men with biopsy-proven prostate cancer managed by active surveillance were included in this HIPPA compliant, IRB approved study. We reviewed baseline MR imaging scans for the presence of a suspicious findings on T2-weighted imaging, MR spectroscopic imaging (MRSI), and diffusion-weighted MR imaging (DWI). The Gleason grades at subsequent biopsy were recorded. A Cox proportional hazard model was used to determine the predictive value of MR imaging for Gleason grades, and the model performance was described using Harrell's C concordance statistic and 95% confidence intervals (CIs). The Cox model that incorporated T2-weighted MR imaging, DWI, and MRSI showed that only T2-weighted MR imaging and DWI are independent predictors of biopsy upgrade (T2; HR = 2.46; 95% CI 1.36-4.46; P = 0.003-diffusion; HR = 2.76; 95% CI 1.13-6.71; P = 0.03; c statistic = 67.7%; 95% CI 61.1-74.3). There was an increasing rate of Gleason score upgrade with a greater number of concordant findings on multiple MR sequences (HR = 2.49; 95% CI 1.72-3.62; P < 0.001). Abnormal results on multiparametric prostate MRI confer an increased risk for Gleason score upgrade at subsequent biopsy in men with localized prostate cancer managed by active surveillance. These results may be of help in appropriately selecting candidates for active surveillance.
    Abdominal Imaging 04/2014; · 1.91 Impact Factor
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  • Shoshana B. Ginsburg, Mirabela Rusu, John Kurhanewicz, Anant Madabhushi
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    ABSTRACT: In this study we explore the ability of a novel machine learning approach, in conjunction with computer-extracted features describing prostate cancer morphology on pre-treatment MRI, to predict whether a patient will develop biochemical recurrence within ten years of radiation therapy. Biochemical recurrence, which is characterized by a rise in serum prostate-specific antigen (PSA) of at least 2 ng/mL above the nadir PSA, is associated with increased risk of metastasis and prostate cancer-related mortality. Currently, risk of biochemical recurrence is predicted by the Kattan nomogram, which incorporates several clinical factors to predict the probability of recurrence-free survival following radiation therapy (but has limited prediction accuracy). Semantic attributes on T2w MRI, such as the presence of extracapsular extension and seminal vesicle invasion and surrogate measure- ments of tumor size, have also been shown to be predictive of biochemical recurrence risk. While the correlation between biochemical recurrence and factors like tumor stage, Gleason grade, and extracapsular spread are well- documented, it is less clear how to predict biochemical recurrence in the absence of extracapsular spread and for small tumors fully contained in the capsule. Computer{extracted texture features, which quantitatively de- scribe tumor micro-architecture and morphology on MRI, have been shown to provide clues about a tumor's aggressiveness. However, while computer{extracted features have been employed for predicting cancer presence and grade, they have not been evaluated in the context of predicting risk of biochemical recurrence. This work seeks to evaluate the role of computer-extracted texture features in predicting risk of biochemical recurrence on a cohort of sixteen patients who underwent pre{treatment 1.5 Tesla (T) T2w MRI. We extract a combination of first-order statistical, gradient, co-occurrence, and Gabor wavelet features from T2w MRI. To identify which of these T2w MRI texture features are potential independent prognostic markers of PSA failure, we implement a partial least squares (PLS) method to embed the data in a low{dimensional space and then use the variable importance in projections (VIP) method to quantify the contributions of individual features to classification on the PLS embedding. In spite of the poor resolution of the 1.5 T MRI data, we are able to identify three Gabor wavelet features that, in conjunction with a logistic regression classifier, yield an area under the receiver operating characteristic curve of 0.83 for predicting the probability of biochemical recurrence following radiation therapy. In comparison to both the Kattan nomogram and semantic MRI attributes, the ability of these three computer-extracted features to predict biochemical recurrence risk is demonstrated.
    SPIE Medical Imaging; 03/2014
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    ABSTRACT: To investigate the role of endorectal MR imaging and MR spectroscopic imaging in defining the contour of treatable intraprostatic tumor foci in prostate cancer, since targeted therapy requires accurate target volume definition. We retrospectively identified 20 patients with prostate cancer who underwent endorectal MR imaging and MR spectroscopic imaging prior to radical prostatectomy and subsequent creation of detailed histopathological tumor maps from whole-mount step sections. Two experienced radiologists independently reviewed all MR images and electronically contoured all suspected treatable (⩾0.5cm(3)) tumor foci. Deformable co-registration in MATLAB was used to calculate the margin of error between imaging and histopathological contours at both capsular and non-capsular surfaces and the treatment margin required to ensure at least 95% tumor coverage. Histopathology showed 17 treatable tumor foci in 16 patients, of which 8 were correctly identified by both readers and an additional 2 were correctly identified by reader 2. For all correctly identified lesions, both readers accurately identified that tumor contacted the prostatic capsule, with no error in contour identification. On the non-capsular border, the median distance between the imaging and histopathological contour was 1.4mm (range, 0-12). Expanding the contour by 5mm at the non-capsular margin included 95% of tumor volume not initially covered within the MR contour. Endorectal MR imaging and MR spectroscopic imaging can be used to accurately contour treatable intraprostatic tumor foci; adequate tumor coverage is achieved by expanding the treatment contour at the non-capsular margin by 5mm.
    Radiotherapy and Oncology 01/2014; · 4.86 Impact Factor
  • Rahul Aggarwal, John Kurhanewicz
    Nature Reviews Urology 01/2014; · 4.79 Impact Factor
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    ABSTRACT: To demonstrate simultaneous hyperpolarization and imaging of three (13) C-labeled perfusion MRI contrast agents with dissimilar molecular structures ([(13) C]urea, [(13) C]hydroxymethyl cyclopropane, and [(13) C]t-butanol) and correspondingly variable chemical shifts and physiological characteristics, and to exploit their varying diffusibility for simultaneous measurement of vascular permeability and perfusion in initial preclinical studies. Rapid and efficient dynamic multislice imaging was enabled by a novel pulse sequence incorporating balanced steady state free precession excitation and spectral-spatial readout by multiband frequency encoding, designed for the wide, regular spectral separation of these compounds. We exploited the varying bilayer permeability of these tracers to quantify vascular permeability and perfusion parameters simultaneously, using perfusion modeling methods that were investigated in simulations. "Tripolarized" perfusion MRI methods were applied to initial preclinical studies with differential conditions of vascular permeability, in normal mouse tissues and advanced transgenic mouse prostate tumors. Dynamic imaging revealed clear differences among the individual tracer distributions. Computed permeability maps demonstrated differential permeability of brain tissue among the tracers, and tumor perfusion and permeability were both elevated over values expected for normal tissues. Tripolarized perfusion MRI provides new molecular imaging measures for specifically monitoring permeability, perfusion, and transport simultaneously in vivo. Magn Reson Med, 2013. © 2013 Wiley Periodicals, Inc.
    Magnetic Resonance in Medicine 12/2013; · 3.40 Impact Factor
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    ABSTRACT: To establish a consensus on the utility of multiparametric magnetic resonance imaging (mpMRI) to identify patients for focal therapy. Topics specifically not included staging of prostate cancer (PCa), but rather identifying the optimal requirements for performing MRI, and the current status of optimally performed mpMRI to a) determine focality of prostate cancer (i.e. localizing small target lesions of 0.5 cm3 and greater), b) to monitor and assess the outcome of focal ablation therapies, and c) to indentify the diagnostic advantages of new MRI methods. In addition, the need for transperineal template saturation biopsies in selecting patients for focal therapy was discussed, if a high quality mpMRI is available. In other words, can mpMRI replace the role of transperineal saturation biopsies in patient selection for focal therapy? Urological surgeons, radiologists, and basic researchers, from Europe and North America participated in a consensus meeting about the use of mpMRI in focal therapy of prostate cancer. The consensus process was face-to-face and specific clinical issues were raised and discussed with agreement sought when possible. All participants are listed among the authors. Consensus was reached on most key aspects of the meeting, however on definition of the optimal requirements for mpMRI, there was 1 dissenting voice. mpMRI is the optimum approach to achieve the objectives needed for focal therapy, if made on a high quality machine (3T with/without endorectal coil or 1.5 with endorectal coil) and judged by an experienced radiologist. Structured and standardized reporting of prostate MRI is paramount. State of the art mpMRI is capable to localize small tumors for focal therapy. State of the art mpMRI is the technique of choice for follow up of focal ablation. The present evidence for MRI in focal therapy is limited. mpMRI is not accurate enough to consistently grade tumor aggressiveness. Template guided saturation biopsies are no longer necessary when a high quality state of the art mpMRI is available, however, suspicious lesion should always be confirmed by (targeted) biopsy.
    BJU International 11/2013; · 3.13 Impact Factor
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    ABSTRACT: (1) To establish a method to evaluate dosimetry at the time of primary prostate permanent implant (pPPI) using MRI of the shrunken prostate at the time of failure (tf). (2) To compare cold spot mapping with sextant-biopsy mapping at tf. Twenty-four patients were referred for biopsy-proven local failure (LF) after pPPI. Multiparametric MRI and combined-sextant biopsy with a central review of the pathology at tf were systematically performed. A model of the shrinking pattern was defined as a Volumetric Change Factor (VCF) as a function of time from time of pPPI (t0). An isotropic expansion to both prostate volume (PV) and seed position (SP) coordinates determined at tf was performed using a validated algorithm using the VCF. pPPI CT-based evaluation (at 4weeks) vs. MR-based evaluation: Mean D90% was 145.23±19.16Gy [100.0-167.5] vs. 85.28±27.36Gy [39-139] (p=0.001), respectively. Mean V100% was 91.6±7.9% [70-100%] vs. 73.1±13.8% [55-98%] (p=0.0006), respectively. Seventy-seven per cent of the pathologically positive sextants were classified as cold. Patients with biopsy-proven LF had poorer implantation quality when evaluated by MRI several years after implantation. There is a strong relationship between microscopic involvement at tf and cold spots.
    Radiotherapy and Oncology 11/2013; · 4.86 Impact Factor
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    ABSTRACT: Numerical simulations were conducted to devise methods for targeted and protracted hyperthermia (40-46 °C, 30-60 min) to the prostate with a commercial MR-guided endorectal ultrasound phased array (2.3 MHz, ExAblate, InSightec). The intention is to fast-track clinical implementation of this FDA approved ablation system for delivering targeted hyperthermia in conjunction with radiation or chemotherapy. Conformable hyperthermia to focal tumors in posterior and hemi-gland prostate was simulated through 3D patient-specific biothermal models and beamformed acoustic patterns that incorporated the specific constraints imposed on the ExAblate array: irregular element spacing, switching speeds, operating power and short pulse duration. Simulations indicated that diverging and iso-phase sonications could treat (T > 41 °C, max < 46 °C) 13-23 cm(3) with ~1.1 W/cm(2), multi-focused patterns could treat 4.0 cm(3) with 3.4 W/cm(2), and curvilinear patterns could treat 6.5 cm(3) with 0.8 W/cm(2) while avoiding rectum, urethra, pubic bone, etc. Custom beamforming identified through simulations was implemented on the ExAblate system and sonications were performed in tissue mimicking phantom material. ExAblate delivered long duration sonications (0.86 W/cm(2)) with these customized beamforming patterns and generated diffuse hyperthermia (ΔT = 4-8 °C) in phantom, monitored with real-time multi-slice MR temperature imaging (3T). [NIH R01CA122276, Focused Ultrasound Foundation.].
    The Journal of the Acoustical Society of America 11/2013; 134(5):4180. · 1.65 Impact Factor
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    ABSTRACT: To investigate the potential clinical utility of endorectal MRI-guided biopsy in patients with known or suspected prostate cancer.
    Journal of Magnetic Resonance Imaging 10/2013; · 2.57 Impact Factor
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    ABSTRACT: C steady state free precession (SSFP) magnetic resonance imaging and effective spin-spin relaxation time (T2) mapping were performed using hyperpolarized [13C]urea and [13C;15 N2]urea injected intravenously in rats. 15N labeling gave large T2 increases both in solution and in vivo due to the elimination of a strong scalar relaxation pathway. The T2 increase was pronounced in the kidney, with [13C;15 N2]urea giving T2 values of 6:31:3 s in the cortex and medulla, and 112 s in the renal pelvis. The measured T2 in the aorta was 1:3 0:3 s. [13C]urea showed shortened T2 values in the kidney of 0:23 0:03 s compared to 0:28 0:03 s measured in the aorta. The enhanced T2 of [13C;15 N2]urea was utilized to generate large signal enhancement by SSFP acquisitions with flip angles approaching the fully refocused regime. Projection images at 0.94 mm in-plane resolution were acquired with both urea isotopes, with [13C;15 N2]urea giving a greater than four-fold increase in SNR over [13C]urea.
    IEEE transactions on medical imaging. 10/2013;
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    ABSTRACT: To evaluate a semiautomatic software-based method of registering in vivo prostate MR images to digital histopathology images using two approaches: (i) in which the prostates were molded to simulate distortion due to the endorectal imaging coil before fixation, and (ii) in which the prostates were not molded. T2-weighted MR images and digitized whole-mount histopathology images were acquired for 26 patients with biopsy-confirmed prostate cancer who underwent radical prostatectomy. Ten excised prostates were molded before fixation. A semiautomatic method was used to align MR images to histopathology. Percent overlap between MR and histopathology images, as well as distances between corresponding anatomical landmarks were calculated and used to evaluate the registration technique for molded and unmolded cases. The software successfully morphed histology-based prostate images into corresponding MR images. Percent overlap improved from 80.4 ± 5.8% before morphing to 99.7 ± 0.62% post morphing. Molded prostates had a smaller distance between landmarks (1.91 ± 0.75 mm) versus unmolded (2.34 ± 0.68 mm), P < 0.08. Molding a prostate before fixation provided a better alignment of internal structures within the prostate, but this did not reach statistical significance. Software-based morphing allowed for nearly complete overlap between the pathology slides and the MR images.J. Magn. Reson. Imaging 2013;00:000-000. © 2013 Wiley Periodicals, Inc.
    Journal of Magnetic Resonance Imaging 10/2013; · 2.57 Impact Factor
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    ABSTRACT: This first-in-man imaging study evaluated the safety and feasibility of hyperpolarized [1-(13)C]pyruvate as an agent for noninvasively characterizing alterations in tumor metabolism for patients with prostate cancer. Imaging living systems with hyperpolarized agents can result in more than 10,000-fold enhancement in signal relative to conventional magnetic resonance (MR) imaging. When combined with the rapid acquisition of in vivo (13)C MR data, it is possible to evaluate the distribution of agents such as [1-(13)C]pyruvate and its metabolic products lactate, alanine, and bicarbonate in a matter of seconds. Preclinical studies in cancer models have detected elevated levels of hyperpolarized [1-(13)C]lactate in tumor, with the ratio of [1-(13)C]lactate/[1-(13)C]pyruvate being increased in high-grade tumors and decreased after successful treatment. Translation of this technology into humans was achieved by modifying the instrument that generates the hyperpolarized agent, constructing specialized radio frequency coils to detect (13)C nuclei, and developing new pulse sequences to efficiently capture the signal. The study population comprised patients with biopsy-proven prostate cancer, with 31 subjects being injected with hyperpolarized [1-(13)C]pyruvate. The median time to deliver the agent was 66 s, and uptake was observed about 20 s after injection. No dose-limiting toxicities were observed, and the highest dose (0.43 ml/kg of 230 mM agent) gave the best signal-to-noise ratio for hyperpolarized [1-(13)C]pyruvate. The results were extremely promising in not only confirming the safety of the agent but also showing elevated [1-(13)C]lactate/[1-(13)C]pyruvate in regions of biopsy-proven cancer. These findings will be valuable for noninvasive cancer diagnosis and treatment monitoring in future clinical trials.
    Science translational medicine 08/2013; 5(198):198ra108. · 14.41 Impact Factor
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    ABSTRACT: The goal of this study was to correlate prostatic metabolite concentrations from snap-frozen patient biopsies of recurrent cancer after failed radiation therapy with histopathological findings, including Ki-67 immunohistochemistry and pathologic grade, in order to identify quantitative metabolic biomarkers that predict for residual aggressive versus indolent cancer. A total of 124 snap-frozen transrectal ultrasound (TRUS)-guided biopsies were acquired from 47 men with untreated prostate cancer and from 39 men with a rising prostate-specific antigen and recurrent prostate cancer following radiation therapy. Biopsy tissues with Ki-67 labeling index ≤ 5% were classified as indolent cancer, while biopsy tissues with Ki-67 labeling index > 5% were classified as aggressive cancer. The majority (15 out of 17) of cancers classified as aggressive had a primary Gleason 4 pattern (Gleason score ≥ 4 + 3). The concentrations of choline-containing phospholipid metabolites (PC, GPC, and free Cho) and lactate were significantly elevated in recurrent cancer relative to surrounding benign tissues. There was also a significant increase in [PC] and reduction in [GPC] between untreated and irradiated prostate cancer biopsies. The concentration of the choline-containing phospholipid metabolites was significantly higher in recurrent aggressive (≈twofold) than in recurrent indolent cancer biopsies, and the receiver operating characteristic (ROC) curve analysis of total choline to creatine ratio (tCho/Cr) demonstrated an accuracy of 95% (confidence interval = 0.88-1.00) for predicting aggressive recurrent disease. The tCho/Cr was significantly higher for identifying recurrent aggressive versus indolent cancer (tCho/Cr = 2.4 ± 0.4 versus 1.5 ± 0.2), suggesting that use of a higher threshold tCho/Cr ratio in future in vivo (1) H MRSI studies could improve the selection and therapeutic planning for patients who would benefit most from salvage focal therapy after failed radiation therapy. Copyright © 2013 John Wiley & Sons, Ltd.
    NMR in Biomedicine 08/2013; · 3.56 Impact Factor

Publication Stats

8k Citations
840.19 Total Impact Points


  • 1990–2014
    • University of California, San Francisco
      • • Division of Hospital Medicine
      • • Department of Radiology and Biomedical Imaging
      • • Department of Urology
      • • Department of Pharmaceutical Chemistry
      San Francisco, California, United States
  • 2013
    • Centre Hospitalier Universitaire de Dijon
      Dijon, Bourgogne, France
  • 2008–2013
    • CSU Mentor
      Long Beach, California, United States
    • University of Toronto
      Toronto, Ontario, Canada
  • 2012
    • Centre Georges-François Leclerc
      Dijon, Bourgogne, France
    • Case Western Reserve University
      • Department of Biomedical Engineering
      Cleveland, Ohio, United States
  • 2011
    • University of São Paulo
      • Departamento de Radiologia (FM) (São Paulo)
      Ribeirão Preto, Estado de Sao Paulo, Brazil
    • University of Maryland, Baltimore
      • Department of Oncology and Diagnostic Sciences
      Baltimore, MD, United States
  • 2009–2011
    • Rutgers, The State University of New Jersey
      • Department of Biomedical Engineering
      New Brunswick, NJ, United States
    • GE India Industrial Pvt. Ltd.
      New Dilli, NCT, India
    • Yale-New Haven Hospital
      New Haven, Connecticut, United States
  • 2010
    • University of Cincinnati
      • Department of Radiology
      Cincinnati, OH, United States
  • 2006–2009
    • University of California, Berkeley
      • • Department of Bioengineering1
      • • Department of Industrial Engineering and Operations Research
      Berkeley, MO, United States
  • 1998–2009
    • Stanford University
      • Department of Radiology
      Stanford, CA, United States
  • 2007
    • University Hospitals Of Leicester NHS Trust
      Leiscester, England, United Kingdom
    • Ludwig-Maximilian-University of Munich
      • Department of Clinical Radiology
      München, Bavaria, Germany
    • Sunnybrook Health Sciences Centre
      Toronto, Ontario, Canada
  • 2001
    • Memorial Sloan-Kettering Cancer Center
      • Department of Radiology
      New York City, NY, United States