Prostate cancer: sextant localization with MR imaging, MR spectroscopy, and 11C-choline PET/CT

Diagnostic efficiency of hybrid imaging using PSMA ligands, PET/CT, PET/MRI and MRI in identifying malignant prostate lesions

OBJECTIVE

The objective of this study was to assess the accuracy of 68Ga-PSMA-11 PET/MRI, 18F-PSMA-1007 PET/CT, 68Ga-PSMA-11 PET/CT, and multiparametric (mp)MRI for the delineating of dominant intraprostatic lesions (IPL).

MATERIALS AND METHODS

35 patients with organ-confined prostate cancer who were assigned to definitive radiotherapy (RT) were divided into three groups based on imaging techniques: 68Ga-PSMA-PET/MRI (n = 9), 18F-PSMA-PET/CT (n = 16) and 68Ga-PSMA-PET/CT (n = 10). All patients without PSMA-PET/MRI received an additional mpMRI. PSMA-PET-based automatic isocontours and manual contours of the dominant IPLs were generated for each modality. The biopsy results were then used to validate whether any of the prostate biopsies were positive in the marked lesion using Dice similarity coefficient (DSC), Youden index (YI), sensitivity and specificity. Factors that can predict the accuracy of IPLs contouring were analysed.

RESULTS

Diagnostic performance was significantly superior both for manual and automatic IPLs contouring using 68Ga-PSMA-PET/MRI (DSC/YI SUV70%-0.62/0.51), 18F-PSMA-PET/CT (DSC/YI SUV70%-0.67/0.53) or 68Ga-PSMA-PET/CT (DSC/YI SUV70%-0.63/0.51) compared to mpMRI (DSC/YI-0.47/0.41; p < 0.001). The accuracy for delineating IPLs was not improved by combination of PET/CT and mpMRI images compared to PET/CT alone. Significantly superior diagnostic accuracy was found for large prostate lesions (at least 15% from the prostate volume) and higher Gleason score (at least 7b) comparing to smaller lesions with lower GS.

CONCLUSION

IPL localization was significantly improved when using PSMA-imaging procedures compared to mpMRI. No significant difference for delineating IPLs was found between hybrid method PSMA-PET/MRI and PSMA-PET/CT. PSMA-based imaging technique should be considered for the diagnostics of IPLs and focal treatment modality.

Non-FDG PET/CT

The major applications for molecular imaging with PET in clinical practice concern cancer imaging. Undoubtedly, 18F-FDG represents the backbone of nuclear oncology as it remains so far the most widely employed positron emitter compound. The acquired knowledge on cancer features, however, allowed the recognition in the last decades of multiple metabolic or pathogenic pathways within the cancer cells, which stimulated the development of novel radiopharmaceuticals. An endless list of PET tracers, substantially covering all hallmarks of cancer, has entered clinical routine or is being investigated in diagnostic trials. Some of them guard significant clinical applications, whereas others mostly bear a huge potential. This chapter summarizes a selected list of non-FDG PET tracers, described based on their introduction into and impact on clinical practice.

"In-Bore" MRI-Guided Prostate Biopsy for Prostate Cancer Diagnosis: Results from 140 Consecutive Patients

Objectives

Transrectal ultrasound-guided biopsy (TRUS-GB) is the current reference standard procedure for diagnosis of prostate cancer (PCa) but this procedure has limitations related to the low detection rate (DR) described in the literature. The aim of the study was to evaluate the DR efficiency, and complication rate in a pure "in-bore" magnetic resonance imaging-guided biopsy (MRI-GB) series according to the Prostate Imaging Reporting and Data System, version 2 (PI-RADS v2).

Materials and Methods

From July 2015 to April 2018, a series of 142 consecutive patients undergoing MRI-GB were prospectively enrolled. According to the European Society of Urogenital Radiology guidelines, the presence of clinically significant PCa (csPCa) on multiparametric magnetic resonance imaging was defined as equivocal, likely, or highly likely according to a PI-RADS v2, score of 3, 4, or 5, respectively.

Results

Of 142 patients, 76 (53.5%) were biopsy naive and 66 (46.5%) had ≤ 1 previous negative set of random TRUS-GB findings. The MRI-GB findings were positive in 75 of 142 patients with a DR of 52.8%. Of the 76 patients with ≤ 1 previous set of TRUS-GB, 43 had PCa found by MRI-GB, with a DR of 57.3%. The DR in the 66 biopsy-naive patients was 48% (32/66). Of the 75 patients with positive biopsy findings, 54 (80.5%) were found to have csPCa on histological examination. Of these 54 patients, 28 had an International Society of Urological Pathology grade 2; 5 had grade 3, 19 had grade 4, and 2 had grade 5. Considering the anatomic distribution of the index lesions using the PI-RADS v2 scheme, the probability of PCa was greater for lesions located in the peripheral zone (55 of 75, 73.3%) than for those in the central zone (20 of 75, 26.7%).

Conclusions

Our study conducted on 142 patients confirmed the greater DR of csPCa by MRI-GB, with a very low number of cores needed and a negligible incidence of complications, especially in patients with a previous negative biopsy. MRI-GB is optimal for the diagnosis of anterior and central lesions.

Nuclear magnetic resonance spectroscopy of human body fluids and in vivo magnetic resonance spectroscopy: Potential role in the diagnosis and management of prostate cancer

Prostate cancer is the most common solid organ cancer in men, and the second most common cause of male cancer-related mortality. It has few effective therapies, and is difficult to diagnose accurately. Prostate-specific antigen (PSA), which is currently the most effective diagnostic tool available, cannot reliably discriminate between different pathologies, and in fact only around 30% of patients found to have elevated levels of PSA are subsequently confirmed to actually have prostate cancer. As such, there is a desperate need for more reliable diagnostic tools that will allow the early detection of prostate cancer so that the appropriate interventions can be applied. Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance spectroscopy (MRS) are 2 high throughput, noninvasive analytical procedures that have the potential to enable differentiation of prostate cancer from other pathologies using metabolomics, by focusing specifically on certain metabolites which are associated with the development of prostate cancer cells and its progression. The value that this type of approach has for the early detection, diagnosis, prognosis, and personalized treatment of prostate cancer is becoming increasingly apparent. Recent years have seen many promising developments in the fields of NMR spectroscopy and MRS, with improvements having been made to hardware as well as to techniques associated with the acquisition, processing, and analysis of related data. This review focuses firstly on proton NMR spectroscopy of blood serum, urine, and expressed prostatic secretions in vitro, and then on 1- and 2-dimensional proton MRS of the prostate in vivo. Major advances in these fields and methodological principles of data collection, acquisition, processing, and analysis are described along with some discussion of related challenges, before prospects that proton MRS has for future improvements to the clinical management of prostate cancer are considered.

ESTRO ACROP consensus guideline on CT- and MRI-based target volume delineation for primary radiation therapy of localized prostate cancer

BACKGROUND AND PURPOSE

Delineation of clinical target volumes (CTVs) remains a weak link in radiation therapy (RT), and large inter-observer variation is seen. Guidelines for target and organs at risk delineation for prostate cancer in the primary setting are scarce. The aim was to develop a delineation guideline obtained by consensus between a broad European group of radiation oncologists.

MATERIAL AND METHODS

An ESTRO contouring consensus panel consisting of leading radiation oncologists and one radiologist with known subspecialty expertise in prostate cancer was asked to delineate the prostate, seminal vesicles and rectum on co-registered CT and MRI scans. After evaluation of the different contours, literature review and multiple informal discussions by electronic mail a CTV definition was defined and a guide for contouring the CTV of the prostate and the rectum was developed.

RESULTS

The panel achieved consensus CTV contouring definitions to be used as guideline for primary RT of localized prostate cancer.

CONCLUSION

The ESTRO consensus on CT/MRI based CTV delineation for primary RT of localized prostate cancer, endorsed by a broad base of the radiation oncology community, is presented to improve consistency and reliability.

Dynamic 11C-Choline PET / CT for the primary diagnosis of prostate cancer

OBJECTIVES

To test the ability of dynamic 11C-PET / CT to discriminate cancerous tissue from background tissue in patients with localized prostate cancer.

MATERIALS AND METHODS

Twenty-four consecutive patients with prostate cancer were prospectively evaluated with dynamic 11C-choline PET / CT prior to radical prostatectomy. The PET / CT scan was divided into 18 sequences of 5 seconds each, followed by 9 sequences of 60 seconds each. Whole-mount sections of harvested prostates served as reference standards. Volumes of interest were positioned on the dynamic PET / CT images and the following quantitative variables were calculated: perfusion coefficient (K1), washout constant (K2), area under the curve (AUC) at 175 and 630 seconds, and average and maximum standardized uptake values (SUVavg, and SUVmax). Wilcoxon signed-ranks test was used to compare benign and cancerous areas of the prostate.

RESULTS

Areas of cancerous tissue were characterized by higher SUVavg and SUVmax than areas of benign tissue (3.67 ± 2.7 vs. 2.08 ± 1.3 and 5.91 ± 4.4 vs. 3.71 ± 3.7, respectively, P < 0.001), in addition to a higher K1 (0.95 ± 0.58 vs. 0.43 ± 0.24, P < 0.001) and greater cumulative tracer uptake, represented by the AUC at 175 and 630 seconds (P <0.001). No associations were found between dynamic parameters and preoperative prostate specific antigen level or Gleason score.

CONCLUSIONS

In this pilot study, 11C-choline PET / CT demonstrated increased tracer uptake with higher values of static and dynamic parameters in areas of prostate cancer compared to areas of benign tissue. Larger studies are warranted to validate these results and examine the potential applicability of 11C-choline dynamic PET / CT for the diagnosis of prostate cancer.

Imaging of Prostate Cancer Using 11C-Choline PET/Computed Tomography

This article reviews the role of ¹¹C-choline-PET/computed tomography (CT) in patients with prostate cancer for diagnosis, staging, and restaging the disease in case of biochemical recurrence after primary treatment. The main application of this imaging procedure is restaging of the disease in case of biochemical recurrence. ¹¹C-Choline-PET/CT proved its value for metastases-directed salvage therapies and for monitoring therapy response in castration-resistant patients. Prostate-specific antigen and prostate-specific antigen kinetics values confirmed their correlation with ¹¹C-choline PET/CT sensitivity.¹¹C-CholinePET/CT, despite low sensitivity to stage disease or in case of biochemical failure with low PSA levels, has an important impact on the management of patients with prostate cancer.

Update on 18F-Fluciclovine PET for Prostate Cancer Imaging

PET is a functional imaging method that can exploit various aspects of tumor biology to enable greater detection of prostate cancer than can be provided by morphologic imaging alone. Anti-1-amino-3-¹⁸F-flurocyclobutane-1-carboxylic acid (¹⁸F-fluciclovine) is a nonnaturally occurring amino acid PET radiotracer that was recently approved by the U.S. Food and Drug Administration for detection of suspected recurrent prostate cancer. The tumor-imaging features of this radiotracer mirror the upregulation of transmembrane amino acid transport that occurs in prostate cancer because of increased amino acid metabolism for energy and protein synthesis. This continuing medical education article provides an overview on ¹⁸F-fluciclovine PET diagnostic capabilities for primary and metastatic disease, including reviews of published comparisons to conventional imaging and other molecular imaging agents. Additionally, the imaging procedure and image interpretation are detailed, including physiologic and pathologic uptake patterns and pitfalls.

Anatomic and Molecular Imaging in Prostate Cancer

Prostate cancer is characterized by a complex set of heterogeneous disease states. This review aims to describe how imaging has been studied within each specific state. As physicians transition into an era of precision medicine, multiparametric magnetic resonance imaging (mpMRI) is proving to be a powerful tool leading the way for a paradigm shift in the diagnosis and management of localized prostate cancer. With further research and development, molecular imaging modalities will likely change the way we approach recurrent and metastatic disease. Given the range of possible oncological progression patterns, a thorough understanding of the underlying carcinogenesis, as it relates to imaging, is a requisite if we are to appropriately manage prostate cancer in future decades.

Prostate cancer as a paradigm of multidisciplinary approach? Highlights from the Italian young radiation oncologist meeting

Aims and background

The diagnostic and therapeutic approach to prostate cancer has evolved rapidly in last decades. Young professionals need an update about these recent developments in order to improve the care of patients treated in their daily clinical practice.

Methods

On May 18, 2013, AIRO Giovani (the young section of the Italian Association of Radiation Oncology) organized a multidisciplinary meeting involving, as speakers, several young physicians from many parts of Italy actively involved in the diagnostic and therapeutic approach to prostate cancer. The meeting was specifically addressed to young physicians (radio-oncologists, urologists, medical oncologists) and presented the state-of-the-art of the diagnostic/therapeutic approach based on the latest evidence on the issue. Highlights of the congress are summarized and presented in this report.

Results

The large participation in the meeting (more than 120 participants were present) confirmed the interest of young radiation oncologists in improving their skills in prostate cancer management. The contributions of the speakers confirmed the need for regular updates, considering the promising results of recently published studies and the many new ongoing trials, on the diagnostic and therapeutic approaches to prostate cancer.

Conclusions

Multidisciplinary meetings are helpful to improve the skills of young professionals.

Multiparametric Magnetic Resonance Imaging of the Prostate for Tumour Detection and Local Staging: Imaging in 1.5T and Histopathologic Correlation

PURPOSE

The study sought to prospectively evaluate which technique among T2-weighted images, dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI), diffusion-weighted (DW) MRI, or a combination of the 2, is best suited for prostate cancer detection and local staging.

METHODS

Twenty-seven consecutive patients with biopsy-proven adenocarcinoma of the prostate underwent MRI on a 1.5T scanner with a surface phased-array coil prior radical prostatectomy. Combined anatomical and functional imaging was performed with the use of T2-weighted sequences, DCE MRI, and DW MRI. We compared the imaging results with whole mount histopathology.

RESULTS

For the multiparametric approach, significantly higher sensitivity values, that is, 53% (95% confidence interval [CI]: 41.0-64.1) were obtained as compared with each modality alone or any combination of the 3 modalities (P < .05). The specificity for this multiparametric approach, being 90.3% (95% CI: 86.3-93.3) was not significantly higher (P < .05) as compared with the values of the combination of T2+DCE MRI, DW+DCE MRI, or DCE MRI alone. Among the 3 techniques, DCE had the best performance for tumour detection in both the peripheral and the transition zone. High negative predictive value rates (>86%) were obtained for both tumour detection and local staging.

CONCLUSIONS

The combination of T2-weighted sequences, DCE MRI, and DW MRI yields higher diagnostic performance for tumour detection and local staging than can any of these techniques alone or even any combination of them.

Molecular imaging for prostate cancer: Performance analysis of 68Ga-PSMA PET/CT versus choline PET/CT

INTRODUCTION

There is a need for a precise and reliable imaging to improve the management of prostate cancer. In recent years the PET/CT with choline has changed the handling of prostate cancer in Europe, and it is commonly used for initial stratification or for the diagnosis of a biochemical recurrence, although it does not lack limitations. Other markers are being tested, including the ligand of prostate-specific membrane antigen (PSMA), that seems to offer encouraging prospects. The goal of this piece of work was to critically review the role of choline and PSMA PET/CT in prostate cancer.

EVIDENCE ACQUISITION

A systematic literature review of databases PUBMED/MEDLINE and EMBASE was conducted searching for articles fully published in English on the PET marker in prostate cancer and its clinical application.

EVIDENCE SYNTHESIS AND DISCUSSION

It seems as 68Ga-PSMA PET/CT is better than PET/CT in prostate cancer to detect primary prostate lesions, initial metastases in the lymph nodes and recurrence. However, further research is required to obtain high-level tests. Also, other PET markers are studied. Moreover, the emergence of a new PET/MR camera could change the performance of PET imaging.

Imaging of Prostate Cancer Using 11C-Choline PET/Computed Tomography

This article reviews the role of ¹¹C-choline-PET/computed tomography (CT) in patients with prostate cancer for diagnosis, staging, and restaging the disease in case of biochemical recurrence after primary treatment. The main application of this imaging procedure is restaging of the disease in case of biochemical recurrence. ¹¹C-Choline-PET/CT proved its value for metastases-directed salvage therapies and for monitoring therapy response in castration-resistant patients. Prostate-specific antigen and prostate-specific antigen kinetics values confirmed their correlation with ¹¹C-choline PET/CT sensitivity.¹¹C-CholinePET/CT, despite low sensitivity to stage disease or in case of biochemical failure with low PSA levels, has an important impact on the management of patients with prostate cancer.

Metabolic Imaging in Prostate Cancer: Where We Are

In recent years, the development of diagnostic methods based on metabolic imaging has been aimed at improving diagnosis of prostate cancer (PCa) and perhaps at improving therapy. Molecular imaging methods can detect specific biological processes that are different when detected within cancer cells relative to those taking place in surrounding normal tissues. Many methods are sensitive to tissue metabolism; among them, positron emission tomography (PET) and magnetic resonance spectroscopic imaging (MRSI) are widely used in clinical practice and clinical research. There is a rich literature that establishes the role of these metabolic imaging techniques as valid tools for the diagnosis, staging, and monitoring of PCa. Until recently, European guidelines for PCa detection still considered both MRSI/MRI and PET/CT to be under evaluation, even though they had demonstrated their value in the staging of high risk PCa, and in the restaging of patients presenting elevated prostatic-specific antigen levels following radical treatment of PCa, respectively. Very recently, advanced methods for metabolic imaging have been proposed in the literature: multiparametric MRI (mpMRI), hyperpolarized MRSI, PET/CT with the use of new tracers and finally PET/MRI. Their detection capabilities are currently under evaluation, as is the feasibility of using such techniques in clinical studies.

PET Tracers Beyond FDG in Prostate Cancer

Conventional anatomical imaging with CT and MRI has limitations in the evaluation of prostate cancer. PET is a powerful imaging technique, which can be directed toward molecular targets as diverse as glucose metabolism, density of prostate-specific membrane antigen receptors, and skeletal osteoblastic activity. Although 2-deoxy-2-18F-FDG-PET is the mainstay of molecular imaging, FDG has limitations in typically indolent prostate cancer. Yet, there are many useful and emerging PET tracers beyond FDG, which provide added value. These include radiotracers interrogating prostate cancer via molecular mechanisms related to the biology of choline, acetate, amino acids, bombesin, and dihydrotestosterone, among others. Choline is used for cell membrane synthesis and its metabolism is upregulated in prostate cancer. 11C-choline and 18F-choline are in wide clinical use outside the United States, and they have proven most beneficial for detection of recurrent prostate cancer. 11C-acetate is an indirect biomarker of fatty acid synthesis, which is also upregulated in prostate cancer. Imaging of prostate cancer with 11C-acetate is overall similar to the choline radiotracers yet is not as widely used. Upregulation of amino acid transport in prostate cancer provides the biologic basis for amino acid-based radiotracers. Most recent progress has been made with the nonnatural alicyclic amino acid analogue radiotracer anti-1-amino-3-18F-fluorocyclobutane-1-carboxylic acid (FACBC or fluciclovine) also proven most useful for the detection of recurrent prostate cancer. Other emerging PET radiotracers for prostate cancer include the bombesin group directed to the gastrin-releasing peptide receptor, 16β-18F-fluoro-5α-dihydrotestosterone (FDHT) that binds to the androgen receptor, and those targeting the vasoactive intestinal polypeptide receptor 1 (VPAC-1) and urokinase plasminogen activator receptor (uPAR), which are also overexpressed in prostate cancer.

Image-guided high-dose-rate brachytherapy boost to the dominant intraprostatic lesion using multiparametric magnetic resonance imaging including spectroscopy: Results of a prospective study

PURPOSE

To evaluate the long-term outcomes of image-guided high-dose-rate (HDR) brachytherapy boost to the dominant intraprostatic lesion (DIL) using multiparametric magnetic resonance imaging (MRI), including spectroscopy (MRI/magnetic resonance spectroscopy [MRS]).

METHODS AND MATERIALS

Between December 2009 and March 2011, 20 patients with intermediate-risk prostate cancer underwent multiparametric MRI/MRS protocol before treatment. All patients were treated with an external beam radiotherapy dose of 40 Gy, combined with an HDR brachytherapy boost of 15 Gy. Concurrently, the DIL received a boost of 18 Gy. Missing data during followup were handled with multiple imputations.

RESULTS

The median followup was 62 months (range, 23-71 months). Six patients (31%) were classified as favorable intermediate risk and 13 patients (69%) as unfavorable intermediate risk. One patient experienced a prostate-specific antigen biochemical failure, and the 5-year biochemical failure-free survival rate was of 94.7%. The mean International Prostate Symptom Score rose from 7, with respect to baseline, to 10.42 1 month after treatment, and rapidly decreased to 6.97 after 3 months. Grade 1, 2, and 3 acute genitourinary toxicities were reported in 13 (68%), 3 (16%), and 1 (5%) patients, respectively. Grade 1 and 2 late genitourinary toxicities were reported in 9 (53%) and 3 (18%) patients, respectively. Only grade 1 acute and late gastrointestinal toxicities were reported in 4 (21%) and 3 (18%) patients, respectively.

CONCLUSIONS

Delivering an HDR brachytherapy boost to the DIL using image-guided multiparametric MRI/MRS is feasible with good outcomes for biochemical control, acute and late toxicities, and dosimetric constraints for critical organs.

Image-Guided High-Dose-Rate (HDR) Boost Localization Using MRI/MR Spectroscopy: A Correlation Study with Biopsy

PURPOSE

The purpose of this study is to compare the blind interpretations of magnetic resonance imaging (MRI) sequences, diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC), mapping, and magnetic resonance spectroscopy (MRS) of the prostate, in comparison to prostate biopsy to identify a valid dominant intraprostatic lesion (DIL) for dose escalation using high-dose rate brachytherapy.

METHODS

MRI/MRS were performed on 20 patients with intermediate risk adenocarcinoma of the prostate. T1W, T2W, DWI-ADC, and MRS sequences were performed at 1.5 T with pelvic and endorectal coils. An experienced radiologist rated the presence of cancer in each sextant by using a dichotomic approach, first on MR standard acquisitions (T1W and T2W), then on DWI-ADC mapping, and later on MRS images. Areas under the receiver's operating characteristic curve were calculated using a sextant as the unit of analysis. The transrectal ultrasonography-guided biopsy results were used as the reference standard. A table summarizing the MRI/MRS findings was made and compared to the corresponding area in the prostate biopsy report. A perfect match was defined to be the presence of cancer in the same sextant of the MRI/MRS exam and the prostate biopsy.

RESULTS

The interpretation of the MRI/MRS exams per sextant was compared to the diagnostic biopsy report. MRI readings were compared with the biopsy as a surrogate for the complete pathology specimen of the prostate. A sensitivity (Sn) of 98.6% (95% confidence interval, 92.2% - 99.9%) and specificity (Sp) of 60.8% (46.1% - 74.2%) were found. The positive and negative predictive values (PPV, NPV) were 77.3% (67.1% - 85.5%) and 96.9% (83.8% - 99.9%), respectively. When MRS readings were compared with biopsy, we found a Sn of 96.4% (87.7% - 99.6%) and Sp of 54.8% (38.7% - 70.2%). The PPV and NPV were 74% (62.4% - 83.6%) and 92% (74% - 99%), respectively. DWI-ADC mapping results were also compared with biopsy. We found a Sn and Sp of 93.7% (84.5% - 98.2%) and 82.1% (66.5% - 92.5%), respectively, and a PPV and NPV of 89.4% (79.4% - 95.6%) and 88.9% (73.9% - 96.9%), respectively. Finally, after combining MRI, MRS, and DWI-ADC mapping, compared with biopsy, we obtained a Sn, Sp, PPV, and NPV of 100% (94.8% - 100%), 49% (34.8% - 63.4%), 72.6% (62.5% - 81.3%), and 100% (86.3% - 100%), respectively.

CONCLUSIONS

The combination of MRI/MRS is a sensitive tool for both the structural and metabolic evaluation of prostate cancer location. MRI/MRS exams are useful to delineate a DIL for high-dose-rate (HDR) intraprostatic boost.

[Focus on molecular imaging in prostate cancer]

INTRODUCTION

Prostate cancer is the most frequent cancer in men in France and it is a public health issue. This cancer is heterogenous. There is a clinical need of an accurate non-invasive imaging method to improve diagnosis, guide the choice of therapy and evaluate its efficacy. We undertook to critically review the different molecular imaging probes, currently used or in clinical trial.

METHOD

A systematic review of the literature was performed in Pubmed/Medline database by searching for articles in French or English published on PET tracer in prostate cancer in clinical application.

RESULTS

Several PET tracers are under investigation because of the low performance of the FDG in prostate cancer. In France, only two new PET tracers have the marketing authorization: the NaF and choline, but these tracers have several limitations. The NaF analyses only bone metastasis. The choline has changed the recurrence of prostate cancer but is not effective for recurrence with low PSA, furthermore its sensitivity is low for the detection of lymph nodes metastasis in initial disease. Several tracers in trial including the PSMA offer encouraging prospects in initial staging and for recurrences.

CONCLUSION

An accurate knowledge in molecular biology allowed to develop the metabolic imagery. Many new tracers are under evaluation in prostate cancer. The indication of each of them needs to be established.

Diagnostic value of integrated PET/MRI for detection and localization of prostate cancer: Comparative study of multiparametric MRI and PET/CT

PURPOSE

To evaluate the diagnostic value of integrated positron emission tomography/magnetic resonance imaging (PET/MRI) compared with conventional multiparametric MRI and PET/computed tomography (CT) for the detailed and accurate segmental detection/localization of prostate cancer.

MATERIALS AND METHODS

Thirty-one patients who underwent integrated PET/MRI using ¹⁸ F-choline and ¹⁸ F-FDG with an integrated PET/MRI scanner followed by radical prostatectomy were included. The prostate was divided into six segments (sextants) according to anatomical landmarks. Three radiologists noted the presence and location of cancer in each sextant on four different image interpretation modalities in consensus (1, multiparametric MRI; 2, integrated ¹⁸ F-FDG PET/MRI; 3, integrated ¹⁸ F-choline PET/MRI; and 4, combined interpretation of 1 and ¹⁸ F-FDG PET/CT). Sensitivity, specificity, accuracy, positive and negative predictive values, likelihood ratios, and diagnostic performance based on the DOR (diagnostic odds ratio) and NNM (number needed to misdiagnose) were evaluated for each interpretation modality, using the pathologic result as the reference standard. Detection rates of seminal vesicle invasion and extracapsular invasion were also evaluated.

RESULTS

Integrated ¹⁸ F-choline PET/MRI showed significantly higher sensitivity than did multiparametric MRI alone in high Gleason score patients (77.0% and 66.2%, P = 0.011), low Gleason score patients (66.7% and 47.4%, P = 0.007), and total patients (72.5% and 58.0%, P = 0.008) groups. Integrated ¹⁸ F-choline PET/MRI and ¹⁸ F-FDG PET/MRI showed similar sensitivity and specificity to combined interpretation of multiparametric MRI and ¹⁸ F-FDG PET/CT (for sensitivity, 58.0%, 63.4%, 72.5%, and 68.7%, respectively, and for specificity, 87.3%, 80.0%, 81.8%, 72.7%, respectively, in total patient group). However, integrated ¹⁸ F-choline PET/MRI showed the best diagnostic performance (as DOR, 11.875 in total patients, 27.941 in high Gleason score patients, 5.714 in low Gleason score groups) among the imaging modalities, regardless of Gleason score. Integrated ¹⁸ F-choline PET/MRI showed higher sensitivity and diagnostic performance than did integrated ¹⁸ F-FDG PET/MRI (as DOR, 6.917 in total patients, 15.143 in high Gleason score patients, 3.175 in low Gleason score groups) in all three patient groups.

CONCLUSION

Integrated PET/MRI carried out using a dedicated integrated PET/MRI scanner provides better sensitivity, accuracy, and diagnostic value for detection/localization of prostate cancer compared to multiparametric MRI. Generally, integrated ¹⁸ F-choline PET/MRI shows better sensitivity, accuracy, and diagnostic performance than does integrated ¹⁸ F-FDG PET/MRI as well as combined interpretation of multiparametric MRI with ¹⁸ F-FDG PET/CT.

LEVEL OF EVIDENCE

2 J. Magn. Reson. Imaging 2017;45:597-609.

Multiparametric magnetic resonance imaging: Current role in prostate cancer management

Digital rectal examination, serum prostate-specific antigen screening and transrectal ultrasound-guided biopsy are conventionally used as screening, diagnostic and surveillance tools for prostate cancer. However, they have limited sensitivity and specificity. In recent years, the role of multiparametric magnetic resonance imaging has steadily grown, and is now part of the standard clinical management in many institutions. In multiparametric magnetic resonance imaging, the morphological assessment of T2-weighted imaging is correlated with diffusion-weighted imaging, dynamic contrast-enhanced imaging perfusion and/or magnetic resonance spectroscopic imaging. Multiparametric magnetic resonance imaging is currently regarded as the most sensitive and specific imaging technique for the evaluation of prostate cancer, including detection, staging, localization and aggressiveness evaluation. This article presents an overview of multiparametric magnetic resonance imaging, and discusses the current role of multiparametric magnetic resonance imaging in the different fields of prostate cancer management.

PET Imaging of Prostate Cancer Using Radiolabeled Choline

Although PET using fludeoxyglucose F 18 (FDG) is a promising modality for metabolic imaging of different tumors, the results in prostate cancer have been somewhat inconsistent. Low FDG avidity of most prostate cancer cells and urinary activity are suggested as the main limitations of FDG PET for the evaluation of prostate cancer. Prostate cancer exhibits increased choline metabolism, which is the rationale for using radiolabeled choline for PET. This article describes the basic concepts of radiolabeled choline regarding pharmacokinetics, radiation dosimetry, synthesis, and biodistribution, in addition to advances concerning clinical PET using 11C- and 18F-choline in primary staging and restaging of prostate cancer patients.

Differentiation of prostatitis and prostate cancer using the Prostate Imaging-Reporting and Data System (PI-RADS)

PURPOSE

To determine if prostate cancer (PCa) and prostatitis can be differentiated by using PI-RADS.

MATERIALS AND METHODS

3T MR images of 68 patients with 85 cancer suspicious lesions were analyzed. The findings were correlated with histopathology. T2w imaging (T2WI), diffusion weighted imaging (DWI), dynamic contrast enhancement (DCE), and MR-Spectroscopy (MRS) were acquired. Every lesion was given a single PI-RADS score for each parameter, as well as a sum score and a PI-RADS v2 score. Furthermore, T2-morphology, ADC-value, perfusion type, citrate/choline-level, and localization were evaluated.

RESULTS

44 of 85 lesions showed PCa (51.8%), 21 chronic prostatitis (24.7%), and 20 other benign tissue such as hyperplasia or fibromuscular tissue (23.5%). The single PI-RADS score for T2WI, DWI, DCE, as well as the aggregated score including and not including MRS, and the PI-RADS v2-score were all significantly higher for PCa than for prostatitis or other tissue (p<0.001). The single PI-RADS score for MRS and the PI-RADS sum score including MRS were significantly higher for prostatitis than for other tissue (p=0.029 and p=0.020), whereas the other parameters were not different. Prostatitis usually presented borderline pathological PI-RADS scores, showed restricted diffusion with ADC≥900mm(2)/s in 100% of cases, was more often indistinctly hypointense on T2WI (66.7%), and localized in the transitional zone (57.1%). An ADC≥900mm(2)/s achieved the highest predictive value for prostatitis (AUC=0.859).

CONCLUSION

Prostatitis can be differentiated from PCa using PI-RADS, since all available parameters are more distinct in cases of cancer. However, there is significant overlap between prostatitis and other benign findings, thus PI-RADS is only suitable to a limited extent for the primary assessment of prostatitis. Restricted diffusion with ADC≥900mm(2)/s is believed to be a good indicator for prostatitis. MRS can help to distinguish between prostatitis and other tissue.

Magnetic resonance-ultrasound fusion prostate biopsy in the diagnosis of prostate cancer

The advent of multiparametric magnetic resonance imaging (MRI) has ushered in a new era for urologists who perform prostate needle biopsies. The fusion of MRI with transrectal ultrasound (US) allows the direct targeting of suspicious lesions, which has been shown to improve the performance of conventional random biopsy techniques by increasing detection of clinically relevant disease while also decreasing detection of low-risk cancer. However, as with any new technology, many questions regarding effectiveness, reproducibility, and generalizability still remain. In this review, we (1) provide a summary of the various sequences that comprise a MRI of the prostate; (2) evaluate the 3 different ways of incorporating MRI into targeted biopsies of the prostate including in-bore MRI-guided biopsy, cognitive fusion, and device-mediated fusion; (3) review the sensitivity of MR-US fusion in the detection of clinically significant and clinically insignificant disease; and (4) review the barriers to the widespread implementation of MR-US fusion into everyday practice. Whereas other articles in this issue of Urologic Oncology Seminars will discuss other aspects of MRI in the management of prostate cancer, the purpose of this article is to provide an overview of MR-US fusion biopsies in the diagnosis of prostate cancer.

Role of multiparametric magnetic resonance imaging in early detection of prostate cancer

Abstract

Most prostate cancers (PC) are currently found on the basis of an elevated PSA, although this biomarker has only moderate accuracy. Histological confirmation is traditionally obtained by random transrectal ultrasound guided biopsy, but this approach may underestimate PC. It is generally accepted that a clinically significant PC requires treatment, but in case of an non-significant PC, deferment of treatment and inclusion in an active surveillance program is a valid option. The implementation of multiparametric magnetic resonance imaging (mpMRI) into a screening program may reduce the risk of overdetection of non-significant PC and improve the early detection of clinically significant PC. A mpMRI consists of T2-weighted images supplemented with diffusion-weighted imaging, dynamic contrast enhanced imaging, and/or magnetic resonance spectroscopic imaging and is preferably performed and reported according to the uniform quality standards of the Prostate Imaging Reporting and Data System (PIRADS). International guidelines currently recommend mpMRI in patients with persistently rising PSA and previous negative biopsies, but mpMRI may also be used before first biopsy to improve the biopsy yield by targeting suspicious lesions or to assist in the selection of low-risk patients in whom consideration could be given for surveillance.

Teaching Points

• MpMRI may be used to detect or exclude significant prostate cancer.

• MpMRI can guide targeted rebiopsy in patients with previous negative biopsies.

• In patients with negative mpMRI consideration could be given for surveillance.

• MpMRI may add valuable information for the optimal treatment selection.

Index lesion characterization by (11)C-Choline PET/CT and Apparent Diffusion Coefficient parameters at 3 Tesla MRI in primary prostate carcinoma

BACKGROUND

Index lesion characterization is important in the evaluation of primary prostate carcinoma (PPC). The aim of this study was to analyze the contribution of (11) C-Choline PET/CT and the Apparent Diffusion Coefficient maps (ADC) in detecting the Index Lesion and clinically significant tumors in PPC.

METHODS

Twenty-one untreated patients with biopsy-proven PPC and candidates for radical prostatectomy (RP) were prospectively evaluated by means of Ultra-High Definition PET/CT and 3T MRI, which included T2-weighted imaging (T2WI) and ADC maps obtained from diffusion weighted imaging (DWI). Independent experts analyzed all the images separately and were unaware of the pathological data. In each case, the Index lesion was defined as the largest tumor measured on histopathology (Index H). In addition, the largest lesion observed on MRI (Index MRI) and the highest avid (11) C-Choline uptake lesion (Index PET) were obtained. The Gleason scores (GS) of the tumors were determined. PET/CT and ADC map quantitative parameters were also calculated. Measures of correlation among imaging parameters as well as the sensitivity (S), specificity (Sp), negative and positive predictive values (NPV and PPV) for tumor detection were analyzed. All data was validated with the pathological study.

RESULTS

In the morphological study, 139 foci of carcinoma were identified, 47 of which corresponded to clinically significant tumors (>0.5 cm(3)). The remaining foci presented a maximum diameter (dmax ) of 0.1 cm ± SD 0.75 and were not classified as clinically significant. Thirty-two tumors presented a GS (3 + 3), nine GS (3 + 4), and six GS (4 + 3). A total of 21 Index H (dmax = 1.37 cm SD ± 0.61) were identified. The S, Sp, NPV, and PPV for tumor detection with PET were 100%, 70%, 83%, 100%, and for MRI were 46%, 100%, 100%, 54%, respectively. Both Index PET and Index MRI were complementary and identified 95% of the Index H when quantitative criteria were used.

CONCLUSION

In spite of the fact that PET imaging has higher tumor sensitivity than MRI, (11) C-Choline PET and ADC maps have complementary roles in the evaluation of Index Lesion in PPC. Index PET and Index MRI could be complementary targets in the therapeutic planning of PPC.

Multiparametric Prostate Magnetic Resonance Imaging at 3 T: Failure of Magnetic Resonance Spectroscopy to Provide Added Value

PURPOSE

To assess the effect of proton magnetic resonance spectroscopy imaging (MRSI) on the accuracy of multiparametric magnetic resonance imaging (mpMRI) at 3 T for prostate cancer detection.

MATERIALS AND METHODS

Thirty-four patients with prostate cancer were included in this retrospective study. All patients underwent preoperative mpMRI on a 3-T scanner before radical prostatectomy. Magnetic resonance imaging evaluation was based on the prostate imaging-reporting and data system classification system. The accuracy of mpMRI with and without MRSI was determined using receiver operating characteristic analysis, with histology as the reference standard.

RESULTS

Multiparametric MRI including MRSI had a sensitivity of 57.0% and a specificity of 89.2% for sextant-based cancer detection. Multiparametric MRI without MRSI had a sensitivity of 58.1% and a specificity of 87.4%. There was no significant difference regarding the accuracy of mpMRI with and without MRSI (P = 0.48).

CONCLUSION

The addition of MRSI does not improve the accuracy of 3 T mpMRI for sextant localization of prostate cancer.

Innovations in diagnostic imaging of localized prostate cancer

PURPOSE

In recent years, various imaging modalities have been developed to improve diagnosis, staging, and localization of early-stage prostate cancer (PCa).

METHODS

A MEDLINE literature search of the time frame between 01/2007 and 06/2013 was performed on imaging of localized PCa.

RESULTS

Conventional transrectal ultrasound (TRUS) is mainly used to guide prostate biopsy. Contrast-enhanced ultrasound is based on the assumption that PCa tissue is hypervascularized and might be better identified after intravenous injection of a microbubble contrast agent. However, results on its additional value for cancer detection are controversial. Computer-based analysis of the transrectal ultrasound signal (C-TRUS) appears to detect cancer in a high rate of patients with previous biopsies. Real-time elastography seems to have higher sensitivity, specificity, and positive predictive value than conventional TRUS. However, the method still awaits prospective validation. The same is true for prostate histoscanning, an ultrasound-based method for tissue characterization. Currently, multiparametric MRI provides improved tissue visualization of the prostate, which may be helpful in the diagnosis and targeting of prostate lesions. However, most published series are small and suffer from variations in indication, methodology, quality, interpretation, and reporting.

CONCLUSIONS

Among ultrasound-based techniques, real-time elastography and C-TRUS seem the most promising techniques. Multiparametric MRI appears to have advantages over conventional T2-weighted MRI in the detection of PCa. Despite these promising results, currently, no recommendation for the routine use of these novel imaging techniques can be made. Prospective studies defining the value of various imaging modalities are urgently needed.

Three-dimensional proton magnetic resonance spectroscopic imaging with and without an endorectal coil: a prostate phantom study

BACKGROUND

Proton magnetic resonance spectroscopic imaging (MRSI) of the prostate has been used with only a combination of external surface coils. The quality of spectral fitting of the (choline + creatine)/citrate ([Cho + Cr]/Cit) ratio at different field strengths and different coils is important for quantitative/semi-quantitative diagnosis of prostate cancer.

PURPOSE

To evaluate the quality of spectral fitting of the (Cho + Cr)/Cit ratio of a prostate phantom using MRSI at different field strengths and various coils.

MATERIAL AND METHODS

Experiments were using 1.5-T and 3.0-T MR systems. Measurements were taken on a homemade prostate phantom with different coils: spinal array; abdominal array; and endorectal. The signal-to-noise ratio (SNR) of choline, creatine, and citrate peaks as well as the (Cho + Cr)/Cit ratio in each voxel were compared among groups using multi-way analysis of variance.

RESULTS

Magnetic field strength, coils, and plane position had a significant effect on the SNR or (Cho + Cr)/Cit ratio, and there were interactions among groups (all P = 0.000). The 1.5-T (0.228 ± 0.044) exhibited a higher (Cho + Cr)/Cit ratio than the 3.0-T (0.125 ± 0.041) magnetic field strength (F = 3238, P = 0.000). The (Cho + Cr)/Cit ratio of both surface coils (0.183 ± 0.065) and all coils (0.181 ± 0.057) was significantly lower than that of the endorectal coil (0.195 ± 0.077) (both P < 0.05), but significant differences in the mean (Cho + Cr)/Cit ratio were not observed if surface coils and all coils were used (P > 0.05). No significant differences were found among the (Cho + Cr)/Cit ratios of all voxels in the middle planes by the post-hoc analyses (all P > 0.05).

CONCLUSION

Three-dimensional proton MRSI of prostate metabolites in a phantom using surface coils is feasible and reliable, but (Cho + Cr)/Cit ratios acquired at different magnetic fields and coils were different. This difference should be taken into account when calculating this ratio in a field strength-independent way.

Current Status of Hybrid PET/MRI in Oncologic Imaging

OBJECTIVE

This review article explores recent advancements in PET/MRI for clinical oncologic imaging.

CONCLUSION

Radiologists should understand the technical considerations that have made PET/MRI feasible within clinical workflows, the role of PET tracers for imaging various molecular targets in oncology, and advantages of hybrid PET/MRI compared with PET/CT. To facilitate this understanding, we discuss clinical examples (including gliomas, breast cancer, bone metastases, prostate cancer, bladder cancer, gynecologic malignancy, and lymphoma) as well as future directions, challenges, and areas for continued technical optimization for PET/MRI.

Comparison of meta-analyses among elastosonography (ES) and positron emission tomography/computed tomography (PET/CT) imaging techniques in the application of prostate cancer diagnosis

The early diagnosis of prostate cancer (PCa) appears to be of vital significance for the provision of appropriate treatment programs. Even though several sophisticated imaging techniques such as positron emission tomography/computed tomography (PET/CT) and elastosonography (ES) have already been developed for PCa diagnosis, the diagnostic accuracy of these imaging techniques is still controversial to some extent. Therefore, a comprehensive meta-analysis in this study was performed to compare the accuracy of various diagnostic imaging methods for PCa, including 11C-choline PET/CT, 11C-acetate PET/CT, 18F-fluorocholine PET/CT, 18F-fluoroglucose PET/CT, transrectal real-time elastosonography (TRTE), and shear-wave elastosonography (SWE). The eligible studies were identified through systematical searching for the literature in electronic databases including PubMed, Cochrane, and Web of Science. On the basis of the fixed-effects model, the pooled sensitivity (SEN), specificity (SPE), and area under the receiver operating characteristics curve (AUC) were calculated to estimate the diagnostic accuracy of 11C-choline PET/CT, 11C-acetate PET/CT, 18F-fluorocholine (FCH) PET/CT, 18F-fluoroglucose (FDG) PET/CT, TRTE, and SWE. All the statistical analyses were conducted with R language Software. The present meta-analysis incorporating a total of 82 studies demonstrated that the pooled sensitivity of the six imaging techniques were sorted as follows: SWE > 18F-FCH PET/CT > 11C-choline PET/CT > TRTE > 11C-acetate PET/CT > 18F-FDG PET/CT; the pooled specificity were also compared: SWE > 18F-FCH PET/CT > 11C-choline PET/CT > TRTE > 18F-FDG PET/CT > 11C-acetate PET/CT; finally, the pooled diagnostic accuracy of the six imaging techniques based on AUC were ranked as below: SWE > 18F-FCH PET/CT > 11C-choline PET/CT > TRTE > 11C-acetate PET/CT > 18F-FDG PET/CT. SWE and 18F-FCH PET/CT imaging could offer more assistance in the early diagnosis of PCa than any other studied imaging techniques. However, the diagnostic ranking of the six imaging techniques might not be applicable to the clinical phase due to the shortage of stratified analysis.

Initial prostate cancer diagnosis and disease staging--the role of choline-PET-CT

An early and correct diagnosis together with accurate staging of prostate cancer is necessary in order to plan the most appropriate treatment strategy. Morphological imaging modalities such as transrectal ultrasonography (TRUS), CT, and MRI can have some limitations regarding their accuracy for primary diagnosis and staging of prostate cancer; for instance, they have limited specificity in differentiating cancer from benign prostatic conditions and, by using size as the only criterion to characterize lymph node metastases, they might not be accurate enough for tumour characterization. In this scenario, PET-CT with (11)C-labelled or (18)F-labelled choline derivatives provides morphological and functional characterization and could overcome the limitations of the conventional imaging techniques. PET-CT is one of the most investigated molecular imaging modalities for prostate cancer diagnosis and staging. Currently, the main investigations on the role of PET-CT in the diagnosis and staging of prostate cancer have been performed on a retrospective basis and this type of analysis might be one of the main reasons why different results regarding its diagnostic accuracy have been reported.

Comparison of [(11)C]choline Positron Emission Tomography With T2- and Diffusion-Weighted Magnetic Resonance Imaging for Delineating Malignant Intraprostatic Lesions

PURPOSE

The purpose of this study was to compare the accuracy of [(11)C]choline positron emission tomography (CHOL-PET) with that of the combination of T2-weighted and diffusion-weighted (T2W/DW) magnetic resonance imaging (MRI) for delineating malignant intraprostatic lesions (IPLs) for guiding focal therapies and to investigate factors predicting the accuracy of CHOL-PET.

METHODS AND MATERIALS

This study included 21 patients who underwent CHOL-PET and T2W/DW MRI prior to radical prostatectomy. Two observers manually delineated IPL contours for each scan, and automatic IPL contours were generated on CHOL-PET based on varying proportions of the maximum standardized uptake value (SUV). IPLs identified on prostatectomy specimens defined reference standard contours. The imaging-based contours were compared with the reference standard contours using Dice similarity coefficient (DSC), and sensitivity and specificity values. Factors that could potentially predict the DSC of the best contouring method were analyzed using linear models.

RESULTS

The best automatic contouring method, 60% of the maximum SUV (SUV60) , had similar correlations (DSC: 0.59) with the manual PET contours (DSC: 0.52, P=.127) and significantly better correlations than the manual MRI contours (DSC: 0.37, P<.001). The sensitivity and specificity values were 72% and 71% for SUV60; 53% and 86% for PET manual contouring; and 28% and 92% for MRI manual contouring. The tumor volume and transition zone pattern could independently predict the accuracy of CHOL-PET.

CONCLUSIONS

CHOL-PET is superior to the combination of T2W/DW MRI for delineating IPLs. The accuracy of CHOL-PET is insufficient for gland-sparing focal therapies but may be accurate enough for focal boost therapies. The transition zone pattern is a new classification that may predict how well CHOL-PET delineates IPLs.

Role for (11)C-choline PET in active surveillance of prostate cancer

INTRODUCTION

Active surveillance (AS) is an increasingly popular management strategy for men diagnosed with low-risk indolent prostate cancer. Current tests (prostate-specific antigen [PSA], clinical staging, and prostate biopsies) to monitor indolent disease lack accuracy. (11)C-choline positron emission tomography (PET) has excellent detection rates in local and distant recurrence of prostate cancer. We examine (11)C-choline PET for identifying aggressive prostate cancer warranting treatment in the AS setting.

METHODS

In total, 24 patients on AS had clinical assessment and PSA testing every 6 months and (11)C-choline PET and prostate biopsies annually. The sensitivity and specificity to identify prostate cancer and progressive disease (PD) were calculated for each (11)C-choline PET scan.

RESULTS

In total, 62 biopsy-paired, serial (11)C-choline PET scans were analyzed using a series of standard uptake value-maximum (SUVmax) cut-off thresholds. During follow-up (mean 25.3 months), 11 of the 24 low-risk prostate cancer patients developed PD and received definitive treatment. The prostate cancer detection rate with (11)C-choline PET had moderate sensitivity (72.1%), but low specificity (45.0%). PD prediction from baseline (11)C-choline PET had satisfactory sensitivity (81.8%), but low specificity (38.5%). The addition of clinical parameters to the baseline (11)C-choline PET improved specificity (69.2%), with a slight reduction in sensitivity (72.7%) for PD prediction.

CONCLUSIONS

Addition of (11)C-choline PET imaging during AS may help to identify aggressive disease earlier than traditional methods. However, (11)C-choline PET alone has low specificity due to overlap of SUV values with benign pathologies. Triaging low-risk prostate cancer patients into AS versus therapy will require further optimization of PET protocols or consideration of alternative strategies (i.e., magnetic resonance imaging, biomarkers).

ProstateAnalyzer: Web-based medical application for the management of prostate cancer using multiparametric MR imaging

OBJECTIVES

In this paper, we present ProstateAnalyzer, a new web-based medical tool for prostate cancer diagnosis. ProstateAnalyzer allows the visualization and analysis of magnetic resonance images (MRI) in a single framework.

METHODS

ProstateAnalyzer recovers the data from a PACS server and displays all the associated MRI images in the same framework, usually consisting of 3D T2-weighted imaging for anatomy, dynamic contrast-enhanced MRI for perfusion, diffusion-weighted imaging in the form of an apparent diffusion coefficient (ADC) map and MR Spectroscopy. ProstateAnalyzer allows annotating regions of interest in a sequence and propagates them to the others.

RESULTS

From a representative case, the results using the four visualization platforms are fully detailed, showing the interaction among them. The tool has been implemented as a Java-based applet application to facilitate the portability of the tool to the different computer architectures and software and allowing the possibility to work remotely via the web.

CONCLUSION

ProstateAnalyzer enables experts to manage prostate cancer patient data set more efficiently. The tool allows delineating annotations by experts and displays all the required information for use in diagnosis. According to the current European Society of Urogenital Radiology guidelines, it also includes the PI-RADS structured reporting scheme.

Management of urological malignancies: Has positron emission tomography/computed tomography made a difference?

Positron emission tomography/computed tomography (PET/CT) technology has been a significant, but expensive addition to the oncologist's armamentarium. The aim of this review was to determine the clinical utility of PET/CT in urological oncology, its impact on disease outcome and cost-effectiveness. We searched MedLine and peer reviewed journals for all relevant literature available online from the year 2000 until January 2014 regarding the use of PET/CT in the management of urological malignancies. (11)C-choline PET/CT has emerged as a powerful tool for assessment of biochemical relapse in prostate cancer. Use of novel radiotracers like (124)I-girentuximab has shown promise in the diagnosis of clear cell renal carcinoma. Fluorodeoxyglucose PET has a proven role in seminoma for the evaluation of postchemotherapy residual masses and has shown encouraging results when used for detection of metastasis in renal, bladder, and penile cancer. Introduction of novel radiotracers and advanced technology has led to a wider application of PET/CT in urological oncology. However, testicular seminoma aside, its impact on disease outcome and cost-effectiveness still needs to be established.

Kinetic Modeling Application to (18)F-fluoroethylcholine Positron Emission Tomography in Patients with Primary and Recurrent Prostate Cancer Using Two-tissue Compartmental Model

Although ¹⁸F-fludeoxyglucose-positron emission tomography (PET) is the most applied diagnostic method in tumor staging, its role in prostate cancer (PCA) is limited because glucose metabolism tends to be low unless PCA has high Gleason score. Alternatively, choline PET was introduced as a valuable imaging method. Kinetic analysis of PET acquisition has increasingly gained momentum as an investigative tool because it provides a non-invasive approach to obtain kinetic and metabolic data from tissues of interest including transport and metabolism of the administered material. In this regard, we sought to apply it in ¹⁸F-fluoroethylcholine (FECH)-PET/computed tomography (CT) in patients with PCA. 64 patients, the mean age 69 (range: 47-87 years) with primary/recurrent PCA were encompassed. They underwent ¹⁸F-FECH-PET started with a dynamic acquisition using a 20-frame each 30 s over the prostate region and followed at 1 h post-injection by a static whole body imaging. The kinetic evaluation of the data was performed using the software package PMOD (PMOD Technologies Ltd., Zürich, Switzerland). Significant increase in mean values for K1, K3, FD, standardized uptake value (SUV) and global influx in tumor tissue versus normal tissue (P < 0.05). Moderate but significant correlation (r: 0.28, P = 0.023) between SUV and K1. By contrast, no correlation between SUV and K3 (r: −0.08, P = 0.79). In patients with recurrent tumors, there is no significant difference in all kinetic parameters and SUV (P > 0.1) between the different types of recurrences. The kinetic analysis of dynamic FECH-PET provides a novel method in primary PCA diagnosis and could be of potential value in the delineation of tumor focus.

Evaluation of 11C-choline PET/CT for primary diagnosis and staging of urothelial carcinoma of the upper urinary tract: a pilot study

Purpose

We conducted a pilot study to prospectively evaluate the efficacy of PET/CT with ¹¹C-choline (choline PET/CT) for primary diagnosis and staging of urothelial carcinoma of the upper urinary tract (UUT-UC).

Methods

Enrolled in this study were 16 patients (9 men, 7 women; age range 51 – 83 years, mean ± SD 69 ± 10.8 years) with suspected UUT-UC. The patients were examined by choline PET/CT, and 13 underwent laparoscopic nephroureterectomy and partial cystectomy. Lymphadenectomy and chemotherapy were also performed as necessary in some of the patients. Of the 16 patients, 12 were confirmed to have UUT-UC (7 renal pelvis carcinoma and 5 ureteral carcinoma), 1 had malignant lymphoma (ureter), 1 had IgG4-related disease (ureter), and 2 had other benign diseases (ureter).

Results

Of the 16 study patients, 13 showed definite choline uptake in urothelial lesions, and of these, 11 had UUT-UC, 1 had malignant lymphoma, and 1 had IgG4-related disease. Three patients without choline uptake comprised one with UUT-UC and two with benign diseases. Of the 12 patients with UUT-UC, 3 had distant metastases, 2 had metastases only in the regional lymph nodes, and 7 had no metastases. Distant metastases and metastases in the regional lymph nodes showed definite choline uptake. The outcome in patients with UUT-UC, which was evaluated 592 – 1,530 days after surgery, corresponded to the patient classification based on the presence or absence of metastases and locoregional or distant metastases. Choline uptake determined as SUVmax 10 min after administration was significantly higher than at 20 min in metastatic tumours of UUT-UC (p < 0.05), whereas there was no statistically significant difference between the SUVmax values at 10 and those at 20 min in primary tumours of UUT-UC.

Conclusion

This study suggests that choline PET/CT is a promising tool for the primary diagnosis and staging of UUT-UC.

Imaging in prostate carcinoma

Imaging plays a central role in the detection, diagnosis, staging, and follow-up of prostate carcinoma. This article discusses the role of multiple imaging modalities in the diagnosis and staging of prostate cancer, with attention to imaging features of localized and metastatic disease, imaging adjuncts to improve prostate biopsy, and potential imaging biomarkers. In addition, the role of imaging in the management of prostate cancer, with emphasis on surveillance, evaluation of response to new therapies, and detection of recurrent disease is described. Lastly, future directions in prostate cancer imaging are presented.

Study of inter- and intra-observer reproducibility in the interpretation of [(18)F]choline PET/CT examinations in patients suffering from biochemically recurrent prostate cancer following curative treatment

Background

The aim of this study was to investigate the reproducibility of intra- and inter-observer interpretation of [¹⁸F]choline positron emission tomography/computed tomography examinations in patients suffering from biochemically recurrent prostate cancer following curative treatment.

Methods

A total of 60 patients with biochemical recurrence after curative treatment were included in this bicentric study. The interpretations were based on a systematic analysis of several anatomic regions and all the four nuclear medicine physicians used identical result consoles. The examinations were interpreted with no knowledge of the patients' clinical context. Two months later, a second interpretation of all these examinations was performed using the same method, in random order.

Results

To evaluate local recurrences, when the prostate is in place, the results showed moderate inter- and intra-observer reproducibility: concordance of all 4 physicians has a Fleiss' kappa coefficient of 0.553 with a confidence interval of (0.425 to 0.693). For patients who had had a prostatectomy, there was excellent concordance for the negative examinations. For the lymphatic basin, inter- and intra-observer reproducibility was excellent with a Fleiss' kappa coefficient of 0.892 with a confidence interval of (0.788 to 0.975). The lymphatic sub-group analysis was also good. For the lymphatic groups in the right or left hemi-pelves, all Fleiss' kappa and Cohen's kappa coefficients are varying from 0.760 to 1 with narrow confidence intervals from (0.536 to 0.984) to (1 to 1) in favour of good/excellent inter-observer reproducibility. To evaluate bone metastasis, inter-observer reproducibility was good with a Fleiss' kappa coefficient of 0.703 and a confidence interval of (0.407 to 0.881).

Conclusion

Our study is at time the only one on the reproducibility of interpretation of [¹⁸F]choline positron emission tomography/computed tomography examinations, which is a key examination for the treatment of patients suffering biochemical recurrence of prostate cancer. Interpretation of the [¹⁸F]choline positron emission tomography/computed tomography examination is not so useful at prostate level in patients not previously treated with prostatectomy but has a great interest on patients treated by prostatectomy. It showed good concordance in the interpretation of sub-diaphragmatic lymphatic recurrences as well as in bone metastasis.

Current opportunities and challenges of magnetic resonance spectroscopy, positron emission tomography, and mass spectrometry imaging for mapping cancer metabolism in vivo

Cancer is known to have unique metabolic features such as Warburg effect. Current cancer therapy has moved forward from cytotoxic treatment to personalized, targeted therapies, with some that could lead to specific metabolic changes, potentially monitored by imaging methods. In this paper we addressed the important aspects to study cancer metabolism by using image techniques, focusing on opportunities and challenges of magnetic resonance spectroscopy (MRS), dynamic nuclear polarization (DNP)-MRS, positron emission tomography (PET), and mass spectrometry imaging (MSI) for mapping cancer metabolism. Finally, we highlighted the future possibilities of an integrated in vivo PET/MR imaging systems, together with an in situ MSI tissue analytical platform, may become the ultimate technologies for unraveling and understanding the molecular complexities in some aspects of cancer metabolism. Such comprehensive imaging investigations might provide information on pharmacometabolomics, biomarker discovery, and disease diagnosis, prognosis, and treatment response monitoring for clinical medicine.

Metabolic atrophy and 3-T 1H-magnetic resonance spectroscopy correlation after radiation therapy for prostate cancer

OBJECTIVE

To correlate 3-T magnetic resonance spectroscopic imaging (MRSI) with prostate-specific antigen (PSA) levels in patients with prostate cancer treated with external beam radiation therapy to assess the potential advantages of MRSI.

MATERIALS AND METHODS

A total of 50 patients (age range 65-83 years) underwent PSA and MRSI surveillance before and at 3, 6, 12, 18 and 24 months after radiotherapy.

RESULTS

Of the 50 patients examined, 13 patients completely responded to therapy showing metabolic atrophy (MA), defined as a choline-plus-creatine/citrate (CC/C) ratio <0.2, at 3 months; in this group none had biochemical relapse (PSA nadir + 2 ng/mL) by the end of the follow-up. Of the 50 patients, 35 showed a partial response to therapy (CC/C ratio between 0.2 and 0.8) at 3 and 6 months and, of these 35 patients, 30 reached MA at 12 months, while five developed a recurrence (CC/C ratio >0.8). Three of those patients with recurrence had a biochemical relapse at 18 months and the other two at 24 months. Two of the 50 patients did not respond to the treatment, showing persistent disease from the 3rd month (CC/C ratio >0.8); one patient had biochemical relapse at 6 and the other at 12 months.

CONCLUSIONS

MRSI was shown to have a greater potential than PSA level in monitoring patients after radiotherapy, because it anticipates PSA nadir, and biochemical relapse in particular.

Imaging of prostate carcinoma

BACKGROUND

Imaging of prostate carcinoma is an important adjunct to clinical evaluation and prostate specific antigen measurement for detecting metastases and tumor recurrence. In the past, the ability to assess intraprostatic tumor was limited.

METHODS

Pertinent literature was reviewed to describe the capabilities and limitations of the currently available imaging techniques for assessing prostate carcinoma. Evaluation of primary tumor and metastatic disease by ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine techniques is discussed.

RESULTS

Ultrasonography and MRI have limited usefulness for local staging of prostate cancer because of suboptimal sensitivity and specificity for identifying tumor extent and capsular penetration. Additional MRI techniques such as magnetic resonance-based perfusion imaging, diffusion imaging, and spectroscopy may provide incremental benefit. CT and bone scanning provide an assessment of metastatic disease but are also limited by the poor sensitivity of lymph node size as a criterion for detecting metastases. Novel imaging techniques such as hybrid imaging devices in the form of single-photon emission CT/CT gamma cameras, positron emission tomography/CT cameras, and, in the near future, positron emission tomography/MRI combined with tumor specific imaging radiotracers may have a significant impact on tumor staging and treatment response.

CONCLUSIONS

Cross-sectional imaging and scintigraphy have an important role in assessing prostate carcinoma metastases and treatment response. Increasingly, the incremental value of primary tumor imaging through MRI is being realized.