Prostate: high-frequency Doppler US imaging for cancer detection

Value of 68Ga-labeled bombesin antagonist (RM2) in the detection of primary prostate cancer comparing with [18F]fluoromethylcholine PET-CT and multiparametric MRI-a phase I/II study

OBJECTIVES

The bombesin derivative RM2 is a GRPr antagonist with strong binding affinity to prostate cancer (PCa). In this study, the impact of [⁶⁸Ga]Ga-RM2 positron emission tomography-computed tomography (PET-CT) for the detection of primary PCa was compared with that of [¹⁸F]FCH PET-CT and multiparametric magnetic resonance imaging (mpMRI).

METHODS

This phase I/II study was conducted in 30 biopsy-positive PCa subjects. The patients were stratified into high (10 patients), intermediate (10 patients), and low risk (10 patients) for extraglandular metastases as defined by National Comprehensive Cancer Network (NCCN) criteria (NCCN Clinical Practice Guidelines in Oncology, 2016). The prostate gland was classified in 12 anatomic segments for data analysis of the imaging modalities as well as histopathologic findings. The segment with the highest radiotracer uptake was defined as the "index lesion." All cases were scheduled to undergo prostatectomy with pelvic lymph node (LN) dissection in intermediate- and high-risk patients. Intraprostatic and pelvic nodal [⁶⁸Ga]Ga-RM2 and [¹⁸F]FCH PET-CT findings were correlated with mpMRI and histopathologic results.

RESULTS

Of the 312 analyzed regions, 120 regions (4 to 8 lesions per patient) showed abnormal findings in the prostate gland. In a region-based analysis, overall sensitivity and specificity of [⁶⁸Ga]Ga-RM2 PET-CT in the detection of primary tumor were 74% and 90%, respectively, while it was 60% and 80% for [¹⁸F]FCH PET-CT and 72% and 89% for mpMRI. Although the overall sensitivity of [⁶⁸Ga]Ga-RM2 PET-CT was higher compared to that of [¹⁸F]FCH PET-CT and mpMRI, the statistical analysis showed only significant difference between [⁶⁸Ga]Ga-RM2 PET-CT and [¹⁸F]FCH PET-CT in the intermediate-risk group (p = 0.01) and [⁶⁸Ga]Ga-RM2 PET-CT and mpMRT in the high-risk group (p = 0.03). In the lesion-based analysis, there was no significant difference between SUVmax of [⁶⁸Ga]Ga-RM2 and [¹⁸F]FCH PET-CT in the intraprostatic malignant lesions ([⁶⁸Ga]Ga-RM2: mean SUVmax: 5.98 ± 4.13, median: 4.75; [¹⁸F]FCH: mean SUVmax: 6.08 ± 2.74, median: 5.5; p = 0.13).

CONCLUSIONS

[⁶⁸Ga]Ga-RM2 showed promising PET tracer for the detection of intraprostatic PCa in a cohort of patients with different risk stratifications. However, significant differences were only found between [⁶⁸Ga]Ga-RM2 PET-CT and [¹⁸F]FCH PET-CT in the intermediate-risk group and [⁶⁸Ga]Ga-RM2 PET-CT and mpMRT in the high-risk group. In addition, GRP-R-based imaging seems to play a complementary role to choline-based imaging for full characterization of PCa extent and biopsy guidance in low- and intermediate-metastatic-risk PCa patients and has the potential to discriminate them from those at higher risks.

KEY POINTS

• [⁶⁸Ga]Ga-RM2 is a promising PET tracer with a high detection rate for intraprostatic PCa especially in intermediate-risk prostate cancer patients. • GRPr-based imaging seems to play a complementary role to choline-based or PSMA-based PET/CT imaging in selected low- and intermediate-risk PCa patients for better characterization and eventually biopsy guidance of prostate cancer disease.

Prostate Cancer Ultrasound: Is Still a Valid Tool?

Purpose of Review

The main purpose of this paper review is to highlight the latest ultrasound (US) imaging technologies of the prostate gland, an organ increasingly at the center of attention in the field of oncological diseases of the male sex, which needs a 360° evaluation in order to obtain tailored therapeutic planning. Specialist urological evaluation is designated for this purpose, together with integrated prostate imaging which currently tends to focus more and more on the use of US imaging and its state-of-the-art technologies in iconographic diagnosis, biopsy and, sometimes, treatment of prostatic cancer.

Recent Findings

In particular, the main tools to which reference is made, represent a valid aid to basic US technologies already widely known and diffused, like the grayscale US or the Doppler US, for a "multiparametric" evaluation of the prostate cancer. The concept of multiparametricity is explained by the integration of prostate imaging obtained both with the US evaluation of the gland before and after administration of contrast medium, with the elaboration of parametric maps of quantitative measurement of the enhancement, and with elastography that provides information about the tissue consistency, a finding that strongly relates with the degree of cellularity and with the tumor grading.

Summary

Prostate cancer screening consists of dosing serum levels of prostate-specific antigen (PSA) and performing digit-rectal examination (DRE), more or less associated with transrectal prostate ultrasound (TRUS). However, although these are the most common techniques in clinical practice, they have numerous limitations and make the diagnosis of prostate cancer often challenging. The purpose of mp-US is to enrich the clinical-laboratory data and, above all, the standard US imaging with further details to strengthen the suspicion of malignancy of a prostate tumor, which needs to be addressed to diagnostic deepening with biopsy. This review article provides a summary of the current evidence on mp-US imaging in the evaluation of a clinically significant prostate cancer, comparing the data obtained to the imaging of mp-MRI, the reference tool both in diagnosis and staging.

Diagnostic accuracy of the Novel 29 MHz micro-ultrasound "ExactVuTM" for the detection of clinically significant prostate cancer: A prospective single institutional study. A step forward in the diagnosis of prostate cancer

INTRODUCTION AND OBJECTIVE

ExactVuTM is a real-time micro-ultrasound system which provides, according to the Prostate Risk Identification Using Micro-Ultrasound protocol (PRI-MUS), a 300% higher resolution compared to conventional transrectal ultrasound. To evaluate the performance of ExactVuTM in the detection of Clinically significant Prostate Cancer (CsPCa).

MATERIALS AND METHODS

Patients with Prostate Cancer diagnosed at fusion biopsy were imaged with ExactVuTM. CsPCa was defined as any Gleason Score ≥ 3+4. ExactVuTM examination was considered as positive when PRI-MUS score was ≥ 3. PRI-MUS scoring system was considered as correct when the fusion biopsy was positive for CsPCa. A transrectal fusion biopsy- proven CsPCa was considered as a gold standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under the receiver operator characteristic (ROC) curve (AUC) were calculated.

RESULTS

57 patients out of 68 (84%) had a csPCa. PRI-MUS score was correctly assessed in 68% of cases. Regarding the detection of CsPCa, ExactVuTM 's sensitivity, specificity, PPV, and NPV was 68%, 73%, 93%, and 31%, respectively and the AUC was 0.7 (95% CI 0.5-0-8). For detecting CsPCa in the transition/ anterior zone the sensitivity, specificity, PPV, and NPV was 45%, 66%, 83% and 25% respectively ant the AUC was 0.5 (95% CI 0.2-0.9). Accounting only the CsPCa located in the peripheral zone, sensitivity, specificity, PPV, and NPV raised up to 74%, 75%, 94%, 33%, respectively with AUC 0.75 (95% CI 0.5-0-9).

CONCLUSIONS

ExactVuTM provides high resolution of the prostatic peripheral zone and could represent a step forward in the detection of CsPCa as a triage tool. Further studies are needed to confirm these promising results.

Artificial intelligence in multiparametric prostate cancer imaging with focus on deep-learning methods

Prostate cancer represents today the most typical example of a pathology whose diagnosis requires multiparametric imaging, a strategy where multiple imaging techniques are combined to reach an acceptable diagnostic performance. However, the reviewing, weighing and coupling of multiple images not only places additional burden on the radiologist, it also complicates the reviewing process. Prostate cancer imaging has therefore been an important target for the development of computer-aided diagnostic (CAD) tools. In this survey, we discuss the advances in CAD for prostate cancer over the last decades with special attention to the deep-learning techniques that have been designed in the last few years. Moreover, we elaborate and compare the methods employed to deliver the CAD output to the operator for further medical decision making.

Optimal biopsy strategy for prostate cancer detection by performing a Bayesian network meta-analysis of randomized controlled trials

Objective: With the increasing recognition of the over-diagnosis and over-treatment of prostate cancer (PCa), the choice of a better prostate biopsy strategy had confused both the patients and clinical surgeons. Hence, this network meta-analysis was conducted to clarify this question. Methods: In the current network meta-analysis, twenty eligible randomized controlled trials (RCTs) with 4,571 participants were comprehensively identified through Pubmed, Embase and Web of Science databases up to July 2017. The pooled odds ratio (OR) with 95% credible interval (CrI) was calculated by Markov chain Monte Carlo methods. A Bayesian network meta-analysis was conducted by using R-3.4.0 software with the help of package "gemtc" version 0.8.2. Results: Six different PCa biopsy strategies and four clinical outcomes were ultimately analyzed in this study. Although, the efficacy of different PCa biopsy strategies by ORs with corresponding 95% CrIs had not yet reached statistical differences, the cumulative rank probability indicated that overall PCa detection rate from best to worst was FUS-GB plus TRUS-GB, FUS-GB, CEUS, MRI-GB, TRUS-GB and TPUS-GB. In terms of clinically significant PCa detection, CEUS, FUS-GB or FUS-GB plus TRUS-GB had a higher, whereas TRUS-GB or TPUS-GB had a relatively lower significant detection rate. Meanwhile, TPUS-GB or TRUS-GB had a higher insignificant PCa detection rate. As for TRUS-guided biopsy, the general trend was that the more biopsy cores, the higher overall PCa detection rate. As for targeted biopsy, it could yield a comparable or even a better effect with fewer cores, compared with traditional random biopsy. Conclusion: Taken together, in a comprehensive consideration of four clinical outcomes, our outcomes shed light on that FUS-GB or FUS-GB plus TRUS-GB showed their superiority, compared with other puncture methods in the detection of PCa. Moreover, TPUS or TRUS-GB was more easily associated with the over-diagnosis and over-treatment of PCa. In addition, targeted biopsy was obviously more effective than traditional random biopsy. The subsequent RCTs with larger sample sizes were required to validate our findings.

Utility of Ultrasound in the Diagnosis, Treatment, and Follow-up of Prostate Cancer: State of the Art

Prostate cancer screening currently consists of serum prostate-specific antigen and digital rectal examination, followed by transrectal ultrasound-guided biopsy for diagnostic confirmation. Although the current paradigm of prostate cancer screening has led to a decrease in advanced disease and cancer-related mortality, these techniques have limitations in terms of sensitivity and specificity, resulting in missed cancers that are clinically significant and the overdetection of clinically insignificant cancers. New imaging techniques and technologies are required to improve the detection of prostate cancer. This article summarizes the use of novel ultrasound techniques and technologies in the detection, biopsy, and treatment of prostate cancer.

Diagnostic performance of power doppler and ultrasound contrast agents in early imaging-based diagnosis of organ-confined prostate cancer: Is it possible to spare cores with contrast-guided biopsy?

OBJECTIVES

To evaluate the diagnostic performance of gray scale transrectal ultrasound-B-mode US (BMUS), power Doppler (PDUS), and sonographic contrast (CEUS) in early imaging-based diagnosis of localized prostate cancer (PCa) and to compare the diagnostic profitability of randomized biopsy (RB), US-targeted prostate biopsy by means of PDUS and CEUS.

MATERIAL AND METHODS

A single-center, prospective, transversal, epidemiological study was conducted from January 2010 to January 2014. We consecutively included patients who an imaging study of the prostate with BMUS, PDUS, and CEUS was performed, followed by prostate biopsy due to clinical suspicion of prostate cancer (PSA 4-20ng/mL and/or rectal exam suggestive of malignancy). The diagnostic performance of BMUS, PDUS, and CEUS was determined by calculating the Sensitivity (S), Specificity (Sp), Predictive values (PV), and diagnostic odds ratio (OR) of the diagnosis tests and, for these variables, in the population general and based on their clinical stage according to rectal exam (cT1 and cT2). PCa detection rates determined by means of a randomized 10-core biopsy scheme were compared with detection rates of CEUS-targeted (SonoVue) 2-core biopsies.

RESULTS

Of the initial 984 patients, US contrast SonoVue was administered to 179 (18.2%). The PCa detection rate by organ of BMUS/PDUS in the global population was 38% versus 43% in the subpopulation with CEUS. The mean age of the patients was 64.3±7.01years (95% CI, 63.75-64.70); mean total PSA was 8.9±3.61ng/mL (95% CI, 8.67-9.13) and the mean prostate volume was 56.2±29cc (95% CI, 54.2-58.1). The detection rate by organ of targeted biopsy with BMUS, PDUS, and CEUS were as follows: Global population (10.6, 8.2, 24.5%), stage cT1 (5.6, 4.2, 16.4%), and stage cT2 (32.4, 22.3, 43.5%). Comparing the detection rates of the CEUS-targeted biopsy and randomized biopsy, the following results were obtained: Global population (24.5% vs. 41.8%), stage cT1 (16% vs. 35%), and stage cT2 (43.5% vs. 66.6%), with a p value<0.05. Following the "core-by-core" analysis, the detection rates by core of CEUS-targeted biopsy versus randomized biopsy were: Global population (16% vs. 13%), stage cT1 (30.3% vs. 28%), and stage cT2 (48% vs. 37%), with a p value>0.05. The NNT for CEUS-targeted biopsy was 83.3.

CONCLUSIONS

The low sensitivity, specificity, positive predictive and negative predictive values of gray scale-B-mode, PDUS and CEUS represent scant diagnostic performance of these variables in prostate cancer detection. Prostate cancer detection rates yielded by randomized biopsy were superior than the detection rate of targeted biopsy using B-mode, PDUS and CEUS; as a result, randomized biopsy versus CEUS-targeted biopsies cannot be excluded from biopsy strategy plans for the diagnosis of prostate cancer.

A Review of Imaging Methods for Prostate Cancer Detection

Imaging is playing an increasingly important role in the detection of prostate cancer (PCa). This review summarizes the key imaging modalities-multiparametric ultrasound (US), multiparametric magnetic resonance imaging (MRI), MRI-US fusion imaging, and positron emission tomography (PET) imaging-used in the diagnosis and localization of PCa. Emphasis is laid on the biological and functional characteristics of tumors that rationalize the use of a specific imaging technique. Changes to anatomical architecture of tissue can be detected by anatomical grayscale US and T2-weighted MRI. Tumors are known to progress through angiogenesis-a fact exploited by Doppler and contrast-enhanced US and dynamic contrast-enhanced MRI. The increased cellular density of tumors is targeted by elastography and diffusion-weighted MRI. PET imaging employs several different radionuclides to target the metabolic and cellular activities during tumor growth. Results from studies using these various imaging techniques are discussed and compared.

Contrast dispersion imaging for cancer localization

Cancer growth is associated with angiogenic processes in many types of cancer. Several imaging strategies have therefore been developed that target angiogenesis as a marker for cancer localization. To this end, intravascular and extravascular tissue perfusion is typically assessed by dynamic contrast enhanced (DCE) ultrasound (US) and MRI. All the proposed strategies, however, overlook important changes in the microvascular architecture that result from angiogenic processes. To overcome these limitations, we have recently introduced a new imaging strategy that analyzes the intravascular dispersion kinetics of contrast agents spreading through the microvasculature. Contrast dispersion is mainly determined by microvascular multi-path trajectories, reflecting the underlying microvascular architecture. This paper reviews the results obtained for prostate cancer localization by US and MRI dispersion imaging, also presenting the latest new developments and future perspectives.

PET/Computed Tomography in the Individualization of Treatment of Prostate Cancer

Choline PET/computed tomographic (CT) imaging represents the most diffused PET imaging techniques to investigate patients with prostate cancer (PCa). It may show the site of tumor recurrence in a single step examination, earlier than other conventional imaging techniques. In this context, the availability of a diagnostic test capable of differentiating between potentially curable local recurrence and metastatic disease implying palliative approaches may play an important role in those patients in whom targeted therapies could be performed according to choline PET/CT results. This review analyzes the value of choline PET/CT imaging in the evaluation of treatment of patients with PCa.

Comparison of power Doppler ultrasound with gray scale transrectal ultrasound in predicting cancer positive prostate biopsy cores

OBJECTIVE

The aim of this study is to compare the effect of transrectal power Doppler ultrasound (PDUS) and gray scale transrectal ultrasound (TRUS) for the diagnosis of prostate cancer.

MATERIALS AND METHODS

Seventy-six patients evaluated with transrectal PDUS and TRUS underwent eight systematic TRUS guided core-needle biopsies, with additional cores from abnormal areas. Histologic diagnoses were classified as benign prostatic hyperplasia, chronic prostatitis, intraepithelial neoplasia and adenocarcinoma. TRUS and PDUS findings of the cases were recorded.

RESULTS

PDUS sensitivity, specificity, positive predictive value (PPV) and negative predictive values were 81%, 81%, 54% and 94%, respectively. PDUS had a greater sensitivity and specificity than TRUS (43% and 60%, respectively) and identified cancer cases more accurately (Table 2).

CONCLUSION

Hypervascular foci in PDUS signify suitable zones for biopsy. When combined with systematic TRUS guided biopsy, PDUS increases the cancer detection rate with additional biopsies from suspicious hypervascular foci. Transrectal PDUS guided biopsy should be combined with gray scale TRUS guided biopsy to increase accuracy in the diagnosis of prostate cancer.

Transrectal doppler ultrasound during prostate biopsy: clinical utility and limitations

OBJECTIVE

To determine the clinical utility and limitations of guided prostate biopsy Power Doppler in patients with elevated serum PSA levels.

MATERIALS AND METHOD

Prospective study. From April 2012 to May 2013, 111 men over 45 years of age with serum PSA level greater than 4.0ng/dl who underwent a transrectal prostate biopsy were included. The hypoechoic nodules in the peripheral region were considered positive on the gray scale. Subsequently, the study was conducted with the Power Doppler, where the vascularization of suspicious images was analyzed for sampling. In addition, samples were taken from the suspected areas when performing the digital rectal examination. We calculated sensitivity, specificity, positive predictive value and negative predictive value of the three tests (digital rectal examination, standard gray scale ultrasound and power Doppler).

RESULTS

Prostate cancer was diagnosed in 48 of the 111 patients (43%). Fifty-nine cases (53%) were defined as positive with the Power Doppler. Of these, 39 (66%) corresponded to a diagnosis of prostate adenocarcinoma. The Power Doppler was positive in 39 cases of the 48 patients diagnosed with cancer and the gray scale ultrasound was positive in 31 cases. Overall sensitivity of the power Doppler was 81%, specificity 68%, PPV 66% and NPV 82%, which was higher compared to the other methods (P<.05).

CONCLUSION

Currently, prostate biopsy using Power Doppler does not seem to identify prostate cancer with sufficient accuracy to omit the guided systematic biopsy gray scale, the combined use of these methods being preferable.

Novel trends in transrectal ultrasound imaging of prostate gland carcinoma

Carcinoma of the prostate gland is the most common neoplasm in men. Its treatment depends on multiple factors among which local staging plays a significant role. The basic method is transrectal ultrasound imaging. This examination enables imaging of the prostate gland and its abnormalities, but it also allows ultrasound-guided biopsies to be conducted. A conventional gray-scale ultrasound examination enables assessment of the size, echostructure and outlines of the anatomic capsule, but in many cases, neoplastic lesions cannot be observed. For this reason, new sonographic techniques are implemented in order to facilitate detectability of cancer. The usage of contrast agents during transrectal ultrasound examination must be emphasized since, in combination with color Doppler, it facilitates detection of cancerous lesions by visualizing flow which is not observable without contrast enhancement. Elastography, in turn, is a different solution. It uses the differences in tissue elasticity between a neoplastic region and normal prostatic parenchyma that surrounds it. This technique facilitates detection of lesions irrespective of their echogenicity and thereby supplements conventional transrectal examinations. However, the size of the prostate gland and its relatively far location from the transducer may constitute limitations to the effectiveness of elastography. Moreover, the manner of conducting such an examination depends on the examiner and his or her subjective assessment. Another method, which falls within the novel, popular trend of combining imaging methods, is fusion of magnetic resonance imaging and transrectal sonography. The application of multidimensional magnetic resonance imaging, which is currently believed to be the best method for prostate cancer staging, in combination with the availability of a TRUS examination and the possibility of monitoring biopsies in real-time sonography is a promising alternative, but it is associated with higher costs and longer duration of the examination. This paper presents the most important novel trends in transrectal imaging in prostate cancer diagnosis based on the review of the articles available in the PubMed base and published after 2010.

Imaging and intervention in prostate cancer: Current perspectives and future trends

Prostate cancer is the commonest malignancy in men that causes significant morbidity and mortality worldwide. Screening by digital rectal examination (DRE) and serum prostate-specific antigen (PSA) is used despite its limitations. Gray-scale transrectal ultrasound (TRUS), used to guide multiple random prostatic biopsies, misses up to 20% cancers and frequently underestimates the grade of malignancy. Increasing the number of biopsy cores marginally increases the yield. Evolving techniques of real-time ultrasound elastography (RTE) and contrast-enhanced ultrasound (CEUS) are being investigated to better detect and improve the yield by allowing “targeted” biopsies. Last decade has witnessed rapid developments in magnetic resonance imaging (MRI) for improved management of prostate cancer. In addition to the anatomical information, it is capable of providing functional information through diffusion-weighted imaging (DWI), magnetic resonance spectroscopy (MRS), and dynamic contrast-enhanced (DCE) MRI. Multi-parametric MRI has the potential to exclude a significant cancer in majority of cases. Inclusion of MRI before prostatic biopsy can reduce the invasiveness of the procedure by limiting the number of cores needed to make a diagnosis and support watchful waiting in others. It is made possible by targeted biopsies as opposed to random. With the availability of minimally invasive therapeutic modalities like high-intensity focused ultrasound (HIFU) and interstitial laser therapy, detecting early cancer is even more relevant today. [18F]--fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸FDG PET/CT) has no role in the initial evaluation of prostate cancer. Choline PET has been recently found to be more useful. Fluoride-PET has a higher sensitivity and resolution than a conventional radionuclide bone scan in detecting skeletal metastases.

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.

Doppler spectral waveform parameters at neurovascular bundle vessels in patients with prostate biopsy

INTRODUCTION AND OBJECTIVES

There is a need to improve prescreening determination of prostate cancer to better select patients who need biopsy. Such a strategy properly implemented, will decrease the number of negative biopsies for prostate cancer and in turn better balance the risks and morbidity for patients recommended for biopsy. The aim of study is to investigate Doppler spectral waveform parameters of neurovascular bundle (NVB) vessels and determine differences between benign and malignant pathologies.

PATIENTS AND METHODS

We performed a prospective analysis involving 292 patients who received prostate biopsy for elevated prostate-specific antigen (PSA) values or abnormal digital rectal examination, as well as 174 patients with symptomatic benign prostatic hyperplasia. Doppler spectral waveform (DSW) parameters (peak-systolic velocity [PSV], end-diastolic velocity [EDV], and resistive index [RI]) were measured at bilateral NVB vessels through Doppler transrectal ultrasound at the right lateral decubitus position, compared, and analyzed among patients with benign versus malignant histology for each side.

RESULTS

Overall, both PSV and EDV at malignant sides were significantly higher than those at benign sides, as well as lower RI (all p-values <0.05, unpaired t-test). In subgroup analysis with 93 patients of serum PSA between 10 and 20 ng/mL and 56 patients with one-side malignancy, higher EDV and lower RI were significantly associated with malignancies (all p<0.05). The values of PSV and EDV rather than RI might be influenced by the patients' position and RI by the prostate volume.

CONCLUSIONS

In this study, DSW parameters (mainly EDV and RI) at NVB vessels were significantly associated with prostate cancer, particularly in patients with serum PSA of 10-20 ng/mL. It should be in caution that the patients' position and prostate volume may influence the Doppler signal as demonstrated in the current study. These findings can provide more diagnostic information before prostate biopsy.

Focal low-dose rate brachytherapy for the treatment of prostate cancer

Whole-gland low-dose rate (LDR) brachytherapy has been a well-established modality of treating low-risk prostate cancer. Treatment in a focal manner has the advantages of reduced toxicity to surrounding organs. Focal treatment using LDR brachytherapy has been relatively unexplored, but it may offer advantages over other modalities that have established experiences with a focal approach. This is particularly true as prostate cancer is being detected at an earlier and more localized stage with the advent of better detection methods and newer imaging modalities.

In vivo imaging of prostate cancer using [68Ga]-labeled bombesin analog BAY86-7548

PURPOSE

A novel [(68)Ga]-labeled DOTA-4-amino-1-carboxymethyl-piperidine-D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2 peptide (BAY86-7548) having high affinity to bombesin receptor subtype II to detect primary and metastatic prostate carcinoma using positron emission tomography/computed tomography (PET/CT) was synthesized and evaluated for prostate cancer.

EXPERIMENTAL DESIGN

In this first human study with BAY86-7548, 14 men scheduled for radical prostatectomy (n = 11) or with biochemical recurrence after surgery or hormonal therapy (n = 3) were enrolled. The patients received an intravenous injection of BAY86-7548 followed by over 60-minute dynamic imaging of prostate gland (n = 10) and/or subsequent whole-body imaging (n = 14). The visual assessment of PET/CT images included evaluation of intraprostatic (12 subsextants) and pelvic nodal uptake of BAY86-7548 in 11 surgical patients and detection of potential metastatic foci in all patients. In patients with biochemical recurrence, results were compared with those of either [(11)C]-acetate (n = 2) or [(18)F]-fluoromethylcholine (n = 1) PET/CT.

RESULTS

We found a sensitivity, specificity, and accuracy of 88%, 81% and 83%, respectively, for detection of primary PCa and sensitivity of 70% for metastatic lymph nodes using histology as gold standard. BAY86-7548 correctly detected local recurrence in prostate bed and showed nodal relapse in accordance with [(11)C]-acetate PET/CT in 2 patients with biochemical relapse. In the third hormone refractory patient, BAY86-7548 failed to show multiple bone metastases evident on [(18)F]-fluoromethylcholine PET/CT.

CONCLUSION

BAY86-7548 PET/CT is a promising molecular imaging technique for detecting intraprostatic prostate cancer.

[New ultrasound technologies for the diagnostics of prostate cancer]

CLINICAL/METHODOLOGICAL ISSUE

Prostate cancer is the most common cancer in men. The diagnosis is based on prostate-specific antigen (PSA), digital rectal examination (DRE) and transrectal ultrasound (TRUS) guided biopsy. These techniques have considerable limitations, which result in unnecessary biopsies. Furthermore the biopsies are associated with morbidity and costs.

STANDARD RADIOLOGICAL METHODS

Standard gray-scale ultrasound has a low sensitivity and specificity for prostate cancer detection.

METHODOLOGICAL INNOVATIONS

New ultrasound technologies, including color- and power Doppler ultrasound, contrast enhanced US and real-time sonoelastography have shown to improve prostate cancer diagnosis.

PERFORMANCE

Contrast-enhanced ultrasound has shown a sensitivity of 100% (95% CI, 95%), a negative predictive value (NPV) of 99.8% and a positive predictive value (PPV) of 88.8% for prostate cancer detection. Real-time sonoelastography has shown a sensitivity of 86%, a specificity of 81% and NPV of 91% for prostate cancer diagnosis.

ACHIEVEMENTS

Most studies show that these new ultrasound modalities demonstrate a 1.5 to 2.5 times higher detection of prostate cancer per biopsy specimen compared with systematic biopsy. Multicenter studies results are at present lacking but are, however ongoing.

PRACTICAL RECOMMENDATIONS

In patients with suspected prostate cancer (elevated PSA, suspicious DRE) these new ultrasound techniques should be used. These techniques can detect prostate cancer and allow a targeted biopsy approach.

Report of a consensus meeting on focal low dose rate brachytherapy for prostate cancer

What's known on the subject? and What does the study add? Whole gland brachytherapy has been used to successfully treat prostate cancer but the protocol for focal therapy has not previously been established. The consensus findings provide guidance on patient selection for focal brachytherapy as well as recommendations for conducting therapy and patient follow-up. Low dose rate prostate brachytherapy is an effective treatment for localized prostate cancer. Recently, it has been considered for use in a focused manner whereby treatment is targeted only to areas of prostate cancer. The objective of focal brachytherapy is to provide effective cancer control for low-risk disease but with reduced genitourinary and rectal side-effects in a cost-effective way. We report on the outputs of a consensus meeting of international experts in brachytherapy and focal therapy convened to consider the feasibility and potential development of focal brachytherapy. A number of factors were considered for focal brachytherapy including optimal patient selection, disease characterization and localization, treatment protocols and outcome measures. The consensus meeting also addressed the design of a clinical trial that would assess the oncological outcomes and side-effect profiles resulting from focal brachytherapy.

Contrast-enhanced ultrasonography with contrast-tuned imaging technology for the detection of prostate cancer: comparison with conventional ultrasonography

Study Type - Diagnostic (exploratory cohort) Level of Evidence 2b What's known on the subject? and What does the study add? The present study was to perform contrast-tuned imaging (CnTI) technology to detect prostate cancer and compare the use of CnTI technology for the detection of prostate cancer with conventional ultrasonography. The preliminary data from our study suggested that targeted biopsy of the prostate with CnTI technology could improve the cancer detection and detect higher grade prostate cancers.

OBJECTIVES

To perform contrast-enhanced ultrasonography (CEUS) using contrast-tuned imaging (CnTI) technology to detect prostate cancer. To evaluate the detection of prostate cancer with CnTI compared with conventional grey-scale and power Doppler ultrasonography.

PATIENTS AND METHODS

In all, 150 patients referred for prostate biopsy were evaluated using transrectal grey-scale, power Doppler and CnTI ultrasonography. Biopsy was performed at 10 sites in each patient. If an abnormality was found at any of these three ultrasonography examinations, a biopsy specimen was targeted towards from the corresponding site. The performances of the three ultrasonography techniques for prostate cancer detection were compared.

RESULTS

Prostate cancer was detected at 383 sites from 73 patients. The combination of these three examinations detected more patients with prostate cancer than grey-scale (P= 0.002), power Doppler (P= 0.001) or baseline imaging (the combination of grey-scale and power Doppler; P= 0.031) alone. By biopsy site, CnTI had higher sensitivity and accuracy (73.1% and 83.7%) than grey-scale (50.9%; P < 0.001 and 78.8%; P < 0.001) or power Doppler (48.3%; P < 0.001 and 77.7%; P < 0.001), while the specificity was similar for grey-scale (88.4%), power Doppler (87.8%) and CnTI (87.3%; P > 0.05 in each case). CnTI had higher sensitivity (73.1% vs 62.9%; P < 0.001), specificity (87.3% vs 82.1%; P < 0.001) and accuracy (83.7% vs 77.2%; P < 0.001) than baseline imaging. The mean Gleason score of CnTI-positive cases was significantly higher than CnTI-negative cases (7.1 vs 6.3; P= 0.002).

CONCLUSIONS

CEUS using CnTI technology enables a visualization of the microvasculature associated with prostate cancer. CnTI technology could be used to guide biopsy and improve the detection rate of prostate cancer. CnTI technology was able to detect higher grade prostate cancers.

Value of contrast-enhanced sonography with micro flow imaging in the diagnosis of prostate cancer

BACKGROUND

To evaluate the effectiveness of contrast-enhanced sonographic micro flow imaging (MFI) in the diagnosis of prostate cancer.

METHODS

A total of 74 patients referred for prostate biopsy were prospectively evaluated with MFI. The abnormalities were categorized into four patterns: pattern 1: indistinct separation between the inner and outer gland; pattern 2: asymmetrical or focally increased enhancement in the outer gland; pattern 3: enhancement with focal defect; pattern 4: enhancement in the outer gland equal to that of the inner gland. The findings were correlated with Gleason scores.

RESULTS

Prostate cancer was detected in 264 sites in 41 patients. The sensitivity, specificity, accuracy, and positive and negative predictive values for MFI were 81.1%, 84.3%, 83.3%, 68.6%, and 91.3%, respectively. Positive predictive values for the four patterns were 46.0 (pattern 1), 53.6 (pattern 2), 94.3 (pattern 3), and 95.4 (pattern 4). Gleason scores of cancers with patterns 3 (7.09) or 4 (7.51) were significantly higher than those with patterns 1 (6.17) or 2 (6.59) (p = 0.001, p = 0.005, p < 0.001, p < 0.001).

CONCLUSIONS

Some MFI patterns had high positive predictive values and were associated with more aggressive cancers. This could be used to reduce the number of biopsy sites and detect clinically significant cancers.

Choline PET/CT for prostate cancer: main clinical applications

Several studies investigated the potential roles of imaging modalities in prostate cancer patients for the evaluation of intra-prostatic disease, stage and restage. However no precise guidelines exist about the use of imaging modalities, in particular about the role of PET/CT hybrid imaging. Considering the results of the literature and our experience, we tried to summarize the main applications of choline positron emission tomography (PET) in prostate cancer patients. The use of choline PET/CT for initial diagnosis and staging is not recommended as a first-line method. Instead the main and important application of choline PET/CT is represented by the restaging of the disease in case of biochemical relapse for the detection of lymph node and distant recurrence. In particular choline PET/CT could play a crucial role as first diagnostic procedure in prostate cancer patients who show a fast growing Prostate Specific Antigen (PSA) kinetics.

Enhanced transrectal ultrasound modalities in the diagnosis of prostate cancer

Standard grayscale transrectal ultrasound has a poor sensitivity for detection of prostate cancer. Saturation biopsy schemes have improved prostate cancer detection rates over standard template biopsy schemes, but carry additional morbidity and cost. Enhanced ultrasound modalities (EUM), including color and power Doppler, contrast-enhancement, harmonic and flash replenishment imaging, and elastography have demonstrated improved prostate cancer detection. EUM targeting areas with increased or abnormal vascularity or firmness for biopsy offer improved prostate cancer detection. EUM, detect prostate cancer more efficiently than standard ultrasound guided biopsies. These emerging technologies may potentially augment standard prostate biopsy in clinical practice.

The utility of transrectal real-time elastography in the diagnosis of prostate cancer

The aim of this study is to evaluate the diagnostic performance of transrectal real-time elastography (TRTE) to differentiate benign from malignant prostatic lesions, with pathologic diagnosis obtained by prostatic needle biopsy. Conventional gray scale transrectal ultrasonography (TRUS) and power Doppler ultrasonography (PDUS) were performed in 107 men who had elevated serum prostate-specific antigen level >4 ng/mL or abnormal findings on digital rectal examination. For baseline TRUS and PDUS imaging, the suspicion of carcinoma was scored using previously proposed five-point subjective scale. For TRTE imaging, we used newly adopted five-point subjective scale based on the degree and distribution of strain in relation to hypoechoic area, which simultaneously displayed on B-mode image. All patients underwent transperineal systematic 8-cores biopsies, as well as up to four cores of targeted biopsy from suspicious area by TRUS, PDUS and/or TRTE. The samples were diagnosed pathologically and compared with the findings of TRUS, PDUS and TRTE. Prostate cancer was detected in 40 (37%) of 107 patients. When a cutoff point of 3 (displaying focal asymmetric lesion without strain not related to hypoechoic lesion) was used, TRTE had 68% sensitivity, 81% specificity and 76% accuracy. TRTE was comparable with PDUS (70% sensitivity, 75% specificity and 73% accuracy) and had significantly higher sensitivity than TRUS (68% vs. 50%, p = 0.027). Combination of TRTE with PDUS increased sensitivity to 78%. The detection rate of directed biopsy from suspicious area in either TRTE or PDUS (TRTE+PDUS-directed biopsy) was 29% (31/107) by patient and was comparable with systematic biopsy (31%, 33/107, p = 0.86), whereas the detection rate of TRTE+PDUS-directed biopsy by core (55/111, 50%) was significantly higher than systematic biopsy (132/856, 15%, p < 0.0001). For assessing prostatic lesions, TRTE with B-mode image-based scoring had almost the same diagnostic performance as PDUS. Although TRTE+PDUS-directed biopsy detected comparable number of cancers with systematic biopsy, both techniques should be used supplementarily for minimizing the number of missing cancers.

[The contribution of imaging before, during, and after prostatectomy]

Before prostatectomy, imaging has a dual role: detecting cancer and staging it. During prostatectomy, imaging can guide the surgeon by localizing a probable zone of prostate extension that therefore contraindicates vessel and nerve preservation. After la prostatectomy, imaging can be useful to differentiate local recurrence and distant metastasis. New techniques such as dynamic MRI and MRI spectroscopy are very promising.

Appropriate patient selection in the focal treatment of prostate cancer: the role of transperineal 3-dimensional pathologic mapping of the prostate--a 4-year experience

This study was undertaken to evaluate the usefulness of transperineal mapping biopsy of the prostate as a staging procedure in the appropriate selection of patients for treatment with focal cryoablation. Between October 2001 and January 2006, a total of 80 patients underwent extensive template-guided transperineal pathologic mapping of the prostate (3-DPM), in conjunction with repeat transrectal ultrasound (TRUS)-guided biopsies. Before 3-DPM was performed, the following clinical variables were recorded: age, prostate-specific antigen (PSA), percent free PSA, total prostate volume, transition zone volume, Gleason score, TNM stage, number of positive cores, and maximum percent of positive cores. Results of 3-DPM were compared with those of TRUS-guided biopsies to determine patient suitability for focal cryoablation; this served as the study end point. Of 80 study patients, 43 (54%) were deemed unsuitable for focal cryoablation. When compared with 3-DPM in assessing patient suitability for focal cryoablation repeat TRUS-guided biopsies yielded a false-negative rate of 47%, a sensitivity of 54%, and a negative predictive value of 49%. None of the pre-3-DPM variables correlated significantly with patient suitability for focal ablation. Treatment selected by the 80 study patients included total gland cryoablation (30%), expectant management (23%), radical prostatectomy (18%), focal cryoablation (11%), external irradiation (10%), brachytherapy (6%), and combined external irradiation and brachytherapy (1%); 1% were undecided about treatment selection. In this study, we demonstrated that 3-DPM (1) effectively excluded patients with clinically significant unsuspected cancer outside the area destined to be ablated, (2) appeared to do so more effectively than repeat TRUS-guided biopsies, and (3) was able to precisely locate the site of the cancer to be selectively ablated.

Advances in transrectal ultrasound imaging of the prostate

Grayscale imaging of the prostate is the basic method for diagnostic evaluation and biopsy guidance. Doppler imaging may improve sensitivity for detection of prostate cancer. Microbubble contrast agents represent a major advance to more selectively demonstrate neovascular flow within the prostate. Recently, real-time elastography has been introduced to improve detection of cancer based upon changes in tissue stiffness. As diagnostic methods improve, the ultimate hope is to eliminate biopsy in patients without cancer. New ultrasound-based treatment systems, such as high-intensity focused ultrasound ablative therapy for prostate cancer, may someday allow diagnosis and treatment of prostate cancer to be completed in one sitting.

Contrast-enhanced ultrasound for diagnosis of prostate cancer and kidney lesions

PURPOSE OF REVIEW

Conventional ultrasonography of both, kidney and prostate, is limited due to the poor contrast of B-mode imaging for parenchymal disease and limited sensitivity of colour Doppler for the detection of capillaries and deep pedicular vessels. Contrast-enhanced ultrasound (CEUS) overcomes these limitations.

RECENT FINDINGS

CEUS investigates the blood flow of the prostate, allows for prostate cancer visualization and for targeted biopsies. Comparisons between systematic and CEUS-targeted biopsies have shown that the targeted approach detects more cancers with a lower number of biopsy cores and with higher Gleason scores compared with the systematic approach. Also the kidney offers promising applications as CEUS improves the detection of abnormal microvascular and macrovascular disorders.

SUMMARY

In recent literature CEUS has shown its value for diagnosis of both, prostate cancer and kidney lesions. This paper describes recent improvements and future perspectives of CEUS.

Contrast enhanced ultrasound flash replenishment method for directed prostate biopsies

PURPOSE

We evaluated prostate cancer detection with contrast enhanced ultrasound of the prostate using MicroFlow Imaging (Toshiba America Medical Systems, Tustin, California) compared to systematic biopsy.

MATERIALS AND METHODS

A total of 60 patients referred for prostate biopsy were evaluated with pre-contrast and contrast enhanced MicroFlow Imaging transrectal ultrasound. MicroFlow Imaging is a flash replenishment technique that uses high power flash pulses to destroy contrast microbubbles, followed by low power pulses to demonstrate contrast replenishment. A composite image depicting the vascular architecture is constructed through maximum intensity capture of temporal data in consecutive low power images. Using MicroFlow Imaging up to 5 directed biopsy cores were obtained from areas of abnormal vascular enhancement or morphology, followed by a systematic 10-core biopsy protocol.

RESULTS

A biopsy positive for cancer was found in 79 of the 825 cores (10%) from 18 of the 60 subjects (30%). Positive biopsies were obtained in 50 of 600 systematic core biopsies (8.3%) and in 29 of 225 directed cores (13%) (OR 2.02, p = 0.034). Five of the 18 patients diagnosed with cancer were identified only by systematic biopsy, 2 were identified only by directed biopsy with MicroFlow Imaging and 11 were identified by the 2 techniques (p >0.25). Twice the number of patients was detected per core with directed vs systematic biopsy (0.058 vs 0.027).

CONCLUSIONS

The vascular detail provided by MicroFlow Imaging allowed directed biopsy of these areas with increased detection of prostate cancer. Although a minority of cancers were not detected with MicroFlow Imaging directed biopsy, this technique detected twice as many patients with prostate cancer per biopsy core.

Contrast-enhanced versus systematic transrectal ultrasound-guided prostate cancer detection: an overview of techniques and a systematic review

An overview is given of the current conventional and contrast-specific transrectal ultrasound (TRUS) techniques for prostate imaging that may be used for guiding biopsy. Subsequently, a systematic literature search resulted in inclusion of four studies that directly compared systematic and contrast-enhanced-targeted TRUS-guided biopsy of the prostate. All four studies revealed that contrast-enhanced-targeted TRUS-guided biopsy significantly improved the positive biopsy core rate. In the largest study, the mean Gleason score of the contrast-enhanced-targeted TRUS-guided biopsies was significantly higher than that of the systematic biopsies. Future randomized clinical trials, preferably in a non-academic multi-institutional set-up, will have to be performed to confirm the value of contrast-enhanced-targeted TRUS-guided biopsy in regular clinical practice.

Transrectal contrast enhanced ultrasound for diagnosis of prostate cancer

The diagnosis of prostate cancer is based on histology. Prostate biopsies are obtained based on the triad of prostate specific antigen (PSA), digital rectal examination (DRE) and transrectal ultrasound. Because prostate biopsies still have a large percentage of negative outcomes, patient selection and biopsy direction need improvement. This paper describes the recent improvements in prostate cancer imaging, especially contrast-enhanced transrectal ultrasound.

Imaging in genitourinary cancer from the urologists' perspective

It is well established that advances in imaging may lead to early cancer detection, more accurate tumour staging and consequently adequate treatment, better monitoring of the disease and enhanced surveillance for recurrences after treatment. This manuscript reviews the current use of imaging in genitourinary cancer and explores the impact of imaging findings in clinical management. Additionally, an effort has been made to present the emerging imaging modalities and also their possible role in diagnosis and treatment of these cancers.

Imaging prostate cancer: a multidisciplinary perspective

The major goal for prostate cancer imaging in the next decade is more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information. No consensus exists regarding the use of imaging for evaluating primary prostate cancers. Ultrasonography is mainly used for biopsy guidance and brachytherapy seed placement. Endorectal magnetic resonance (MR) imaging is helpful for evaluating local tumor extent, and MR spectroscopic imaging can improve this evaluation while providing information about tumor aggressiveness. MR imaging with superparamagnetic nanoparticles has high sensitivity and specificity in depicting lymph node metastases, but guidelines have not yet been developed for its use, which remains restricted to the research setting. Computed tomography (CT) is reserved for the evaluation of advanced disease. The use of combined positron emission tomography/CT is limited in the assessment of primary disease but is gaining acceptance in prostate cancer treatment follow-up. Evidence-based guidelines for the use of imaging in assessing the risk of distant spread of prostate cancer are available. Radionuclide bone scanning and CT supplement clinical and biochemical evaluation (prostate-specific antigen [PSA], prostatic acid phosphate) for suspected metastasis to bones and lymph nodes. Guidelines for the use of bone scanning (in patients with PSA level > 10 ng/mL) and CT (in patients with PSA level > 20 ng/mL) have been published and are in clinical use. Nevertheless, changes in practice patterns have been slow. This review presents a multidisciplinary perspective on the optimal role of modern imaging in prostate cancer detection, staging, treatment planning, and follow-up.

Prostate cancer screening: the clinical value of diffusion-weighted imaging and dynamic MR imaging in combination with T2-weighted imaging

PURPOSE

To evaluate the clinical value of diffusion-weighted imaging (DWI) and dynamic MRI in combination with T2-weighted imaging (T2W) for the detection of prostate cancer.

MATERIALS AND METHODS

A total of 83 patients with elevated serum prostate specific antigen (PSA) levels (>4.0 ng/mL) were evaluated by T2W, DWI, and dynamic MRI at 1.5 T prior to needle biopsy. The data from the results of the T2W alone (protocol A), combination of T2W and DWI (protocol B), and the combination of T2W+DWI and dynamic MRI (protocol C) were entered into a receiver operating characteristic (ROC) curve analysis, under results of systemic biopsy as the standard of reference.

RESULTS

Prostate cancer was pathologically detected in 44 of the 83 patients. The sensitivity, specificity, accuracy, and the area under the ROC curve (Az) for the detection of prostate cancer were as follows: 73%, 54%, 64%, and 0.711, respectively, in protocol A; 84%, 85%, 84%, and 0.905, respectively, in protocol B; and 95%, 74%, 86%, and 0.966, respectively, in protocol C. The sensitivity, specificity, and accuracy were significantly different between the three protocols (P < 0.01).

CONCLUSION

In patients with elevated serum PSA levels, the combination of T2W, DWI, and dynamic MRI may be a valuable tool for detecting prostate cancer and avoiding an unnecessary biopsy without missing prostate cancer.

Detection of clinical unilateral T3a prostate cancer ? by digital rectal examination or transrectal ultrasonography?

OBJECTIVE

To assess, in a retrospective study, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of digital rectal examination (DRE), transrectal ultrasonography (TRUS) and the combination of both in unilateral clinical T3a (cT3a) prostate cancer.

PATIENTS AND METHODS

The long-term outcome of surgical treatment for locally advanced prostate cancer is very good and surpasses that for radiotherapy outcomes, so it is anticipated that surgical management for cT3a disease will become more important, but staging methods for cT3a disease are not well studied. Between 1990 and 2004, 2240 patients had a radical prostatectomy at our institution; 267 were diagnosed as having clinical cT3a prostate cancer either by DRE or TRUS. The final histopathology was compared with the findings of DRE and TRUS. The sensitivity, specificity, PPV and NPV for DRE, TRUS and the combination of both were calculated.

RESULTS

The sensitivity, specificity, PPV and NPV by DRE only was 90.9%, 15.8%, 47.2% and 67.7%, by TRUS only was 80.2%, 25.3%, 47.1% and 60.7%, and by both DRE and TRUS was 71.1%, 41.1%, 50.0% and 63.2%. Although the sensitivity was lower in the combined group, it had the highest specificity (41.1%) and PPV (50.0%). The combination of DRE and TRUS can detect T3a prostate cancer more accurately than either method alone.

CONCLUSION

Until data on staging methods like magnetic resonance imaging become available, the combination of DRE and TRUS is advisable in selecting cT3a patients for primary radical prostatectomy.

MR-compatible assistance system for punction in a high-field system: device and feasibility of transgluteal biopsies of the prostate gland

We present the first cadavic study results concerning the feasibility of the use of an MR-guided assistance system, Innomotion (Innomedic, Herxheim, Germany), for accurate and consistent placement of percutaneous needles in the prostate gland. The MR-compatible assistance system consists of a C-arch, guiding arm and application module (AMO). T1-weighted fast low angle shot (FLASH) 2-D-GRE sequence (TR/TE=110/4 ms) and T2-weighted turbo spin-echo (TSE)-sequences (TR/TE=3200/97 ms) in transversal orientation were used for the monitoring of the punction of the prostate gland. Planning and control of the intervention is to be made outside the scanner room on a desktop computer that receives DICOM images from the scanner. Servopneumatic drives move the AMO to the insertion point. The physician has to introduce the punction needle manually. The mean deviation of the needle tip to the target in a gel phantom was 0.35 mm. An accurate punction of the prostate gland can easily be performed using this system with a transgluteal access. The T2-weighted images are superior for the evaluation of the prostate anatomy and the needle position during the interventions. In conclusion, our preliminary results indicate that this MR-guided assistance system is suitable for an accurate transgluteal needle placement in the prostate.

Newer Modalities of Ultrasound Imaging and Treatment of the Prostate

Gray-scale ultrasound is widely used for assessing BPH and for obtaining prostate biopsies. However, it has limited value for evaluating cancer in the prostate. To improve ultrasound as an imaging modality of the prostate, many new technologies, such as color and power Doppler, 3-dimensional ultrasound of the prostate, and contrast-enhanced ultrasound have been developed. In addition, treatment modalities using ultrasound for the treatment of BPH have been developed. This review presents the recent developments in ultrasound of the prostate.

A comparison of the diagnostic performance of systematic versus ultrasound-guided biopsies of prostate cancer

Transrectal ultrasound (TRUS) is an important tool for urologists and radiologists in the detection of prostate cancer. Various TRUS-guided biopsy techniques are applied in clinical practice. Frequently, only the detection rates achieved with these methods are compared. Other diagnostic performance parameters, particularly the specificity and negative predictive value, are seldom compared. After extensive assessment of the available literature, this review describes the methods of TRUS-guided biopsy for prostate cancer detection. A distinction was made between systematic biopsies and biopsies that target a perceived (hypoechoic or Doppler-enhancing) lesion on imaging. Subsequently, the diagnostic performance (sensitivity, specificity, positive and negative predictive values, accuracies) was compared between these techniques. Imaging-guided biopsy showed better diagnostic performance than systematic biopsy with higher sensitivity. The combinations of sensitivity and specificity were highest for colour Doppler and contrast-enhanced targeted biopsy. Studies targeting hypoechoic lesions had relatively high sensitivity, but specificity was low. Presently however, with widespread prostate-specific antigen screening, fewer prostate cancers are hypoechoic, and the value of targeting hypoechoic lesions has diminished. Performing colour or contrast-enhanced Doppler biopsy or adding these techniques to systematic biopsies improves diagnostic performance, particularly by increasing sensitivity.

Imaging for Prostate Cancer

The increased incidence and awareness of prostate cancer, together with developments in treatment, has generated a significant need for appropriate imaging to detect and stage the tumour initially, guide radiotherapy delivery and monitor disease on follow-up. Transrectal ultrasound is usually the first imaging investigation, and its role is primarily to guide prostate needle biopsy. It also has an established role in imaging-guided treatments, such as brachytherapy. Magnetic resonance imaging has developed considerably in recent years, and is now the principal staging investigation before treatment. Innovations in functional and biological imaging of the prostate will, in the future, contribute valuable information to support parallel developments in radiotherapy techniques for prostate cancer. The ultimate goal is a coordinated diagnostic and therapeutic approach to individualise and optimise the treatment plan for patients with prostate cancer.