The value of contrast-enhanced transrectal ultrasound in predicting the nature of prostate diseases and the Gleason score of prostate cancer by a subjective blood flow grading scale

Application of Multiple Ultrasonic Techniques in the Diagnosis of Prostate Cancer

Methods for diagnosing prostate cancer (PCa) are developing in the direction of imaging. Advanced ultrasound examination modes include micro-Doppler, computerized-transrectal ultrasound, elastography, contrast-enhanced ultrasound and microultrasound. When two or more of these modes are used in PCa diagnosis, the combined technique is called multiparameter ultrasound (mp-US). Mp-US provides complementary information to multiparameter magnetic resonance imaging (mp-MRI) for diagnosing PCa. At present, no study has attempted to combine the characteristics of different ultrasound modes with advanced classification systems similar to the PIRADS system in mpMRI for the diagnosis of PCa. As an imaging method, mp-US has great potential in the diagnosis of PCa.

Contrast-Enhanced Ultrasound Characteristics of Renal Pelvis Urothelial Carcinoma and Its Relationship with Microvessel Density

We studied the characteristics of contrast-enhanced ultrasound (CEUS) in renal pelvic urothelial carcinomas and explored its performance in assessing microvessel density (MVD) of tumor tissues. We retrospectively analyzed the characteristics of 125 cases, which were confirmed pathologically to be renal pelvic urothelial carcinomas using CEUS. We performed CEUS and found that most tumors presented with an enhanced mode of "slow-in (mean = 16.7 ± 2.6 s, range: 12-25 s), hypo-enhancement and fast-out (mean = 69.3 ± 16.2 s, range: 42-113 s)." However, the wash-in pattern, homogeneity and wash-out pattern observed with CEUS was not correlated with pT stage and grade (p > 0.05). But advanced-pT-stage and high-grade tumors had a higher peak enhancement than early-pT-stage and low-grade tumors (p < 0.01). Peak enhancement obtained with CEUS can be used to evaluate the pT stage and grade of renal pelvic urothelial carcinomas more effectively. The MVD of those tissues was observed using immunohistochemical staining of cluster of differentiation 34 (CD34). MVD in the advanced-pT-stage and high-grade groups was significantly higher than that in the early-pT-stage and low-grade groups (p < 0.01). As tumor pT stage and grade improved, CEUS peak enhancement intensity and MVD of tumors also exhibited an upward trend. CEUS peak enhancement intensity has the potential to determine MVD of renal pelvic urothelial carcinomas.

Contrast-enhanced ultrasound evaluation of pancreatic cancer xenografts in nude mice after irradiation with sub-threshold focused ultrasound for tumor ablation

We evaluated the efficacy of contrast-enhanced ultrasound for assessing tumors after irradiation with sub-threshold focused ultrasound (FUS) ablation in pancreatic cancer xenografts in nude mice. Thirty tumor-bearing nude mice were divided into three groups: Group A received sham irradiation, Group B received a moderate-acoustic energy dose (sub-threshold), and Group C received a high-acoustic energy dose. In Group B, B-mode ultrasound (US), color Doppler US, and dynamic contrast-enhanced ultrasound (DCE-US) studies were conducted before and after irradiation. After irradiation, tumor growth was inhibited in Group B, and the tumors shrank in Group C. In Group A, the tumor sizes were unchanged. In Group B, contrast-enhanced ultrasound (CEUS) images showed a rapid rush of contrast agent into and out of tumors before irradiation. After irradiation, CEUS revealed contrast agent perfusion only at the tumor periphery and irregular, un-perfused volumes of contrast agent within the tumors. DCE-US perfusion parameters, including peak intensity (PI) and area under the curve (AUC), had decreased 24 hours after irradiation. PI and AUC were increased 48 hours and 2weeks after irradiation. Time to peak (TP) and sharpness were increased 24 hours after irradiation. TP decreased at 48 hours and 2 weeks after irradiation. CEUS is thus an effective method for early evaluation after irradiation with sub-threshold FUS.

Contrast-enhanced ultrasound aids in the detection of prostate rhabdomyosarcoma: A case report and literature review

Prostate sarcoma is a rare malignancy with an extremely poor prognosis. The extremely low morbidity and atypical clinical symptoms contribute to a missed diagnosis. The typical features of prostate sarcoma in transrectal ultrasound (US) and magnetic resonance imaging, such as a markedly enlarged volume and irregular prostatic contours, cannot usually be found until dysuria or even uroschesis occurs, and may then be too late to treat. However, there appears to no specific tumor marker for the disease in the serum. The present study reports a case of a young male patient who was diagnosed with prostate rhabdomyosarcoma. This was, to the best of our knowledge, the first case of this diagnosis using contrast-enhanced US (CEUS) when the symptoms were not severe. In this case, the intralesional non-enhancement areas and rim-like hyper-enhancement around the lesion were considered to be the main CEUS features of prostate rhabdomyosarcoma. The present study also reviews the associated literature.

Image-based monitoring of targeted biopsy-proven prostate cancer on active surveillance: 11-year experience

PURPOSE

To report our 11-year experience of Active Surveillance (AS) program focusing on modern transrectal ultrasound (TRUS)-based monitoring of targeted biopsy-proven cancer lesion.

METHODS

Consecutive patients on AS, who had targeted biopsy-proven lesion followed by at least a repeat surveillance biopsy and three times TRUS monitoring of the identical visible lesion, were included. Doppler grade of blood flow signal within the lesion was classified from grade 0 to 3. Biopsy-proven progression was defined as upgrade of Gleason score or 25% or greater increase in cancer core involvement.

RESULTS

Fifty patients were included in this study. Clinical variables (median) included age (61 years), clinical stage (T1c, 42;T2, 8), PSA (4.6 ng/ml), and Gleason score (3 + 3, n = 41;3 + 4, n = 9). Of the 50 patients, 34 demonstrated pathological progression at a median follow-up of 4.4 years. In comparing between without (n = 16) and with (n = 34) pathological progression, there were significant differences in cancer core involvement at entry (p = 0.003), the major axis diameter (p = 0.001) and minor axis diameter (p = 0.001) of the visible lesion at entry, increase in the major axis diameter (p = 0.005) and minor axis diameter (p = 0.013), and upgrade of Doppler grade (p < 0.0001). In multivariate analysis for predicting pathological progression, the increase (≥25%) in diameter of biopsy-proven lesion (hazard ratio, 15.314; p = 0.023) and upgrade of Doppler grade (hazard ratio, 37.409; p = 0.019) were significant risk factors.

CONCLUSIONS

Longitudinal monitoring of the TRUS-visible biopsy-proven cancer provides a new opportunity to perform per-lesion-based AS. The increase in diameter and upgrade of Doppler grade of the lesion were significant risk factors for biopsy-proven progression on AS.

Transrectal Ultrasound (US), Contrast-enhanced US, Real-time Elastography, HistoScanning, Magnetic Resonance Imaging (MRI), and MRI-US Fusion Biopsy in the Diagnosis of Prostate Cancer

CONTEXT

Debates on overdiagnosis and overtreatment of prostate cancer (PCa) are ongoing and there is still huge uncertainty regarding misclassification of prostate biopsy results. Several imaging techniques that have emerged in recent years could overcome over- and underdiagnosis in PCa.

OBJECTIVE

To review the literature on transrectal ultrasound (TRUS)-based techniques (contrast enhancement, HistoScanning, elastography) and magnetic resonance imaging (MRI)-based techniques for a nonsystematic overview of their benefits and limitations.

EVIDENCE ACQUISITION

A comprehensive search of the PubMed database between August 2004 and August 2014 was performed. Studies assessing grayscale TRUS, contrast-enhanced (CE)-TRUS, elastography, HistoScanning, multiparametric MRI (mpMRI), and MRI-TRUS fusion biopsy were included. Publications before 2004 were included if they reported the principle or the first clinical results for these techniques.

EVIDENCE SYNTHESIS

Grayscale TRUS alone cannot detect PCa foci (detection rate 23-29%). TRUS-based (elastography) and MRI-based techniques (MRI-TRUS fusion biopsy) have significantly improved PCa diagnostics, with sensitivity of 53-74% and specificity of 72-95%. HistoScanning does not provide convincing or homogeneous results (specificity 19-82%). CE-TRUS seems to be user dependent; it is used in a low number of high-volume centers and has wide ranges for sensitivity (54-79%) and specificity (42-95%). For all the techniques reviewed, prospective multicenter studies with consistent definitions are lacking.

CONCLUSIONS

Standard grayscale TRUS is unreliable for PCa detection. Among the techniques reviewed, mpMRI and MRI-TRUS fusion biopsy seem to be suitable for enhancing PCa diagnostics. Elastography shows promising results according to the literature. CE-TRUS yields very inhomogeneous results and might not be the ideal technique for clinical practice. The value of HistoScanning must be questioned according to the literature.

PATIENT SUMMARY

New imaging modalities such as elastography and magnetic resonance imaging/transrectal ultrasound fusion biopsies have improved the detection of prostate cancer. This may lower the burden of overtreatment as a result of more precise diagnosis.

Dynamic contrast-enhanced ultrasound for quantification of tissue perfusion

Dynamic contrast-enhanced ultrasound (US) imaging, a technique that uses microbubble contrast agents with diagnostic US, has recently been technically summarized and reviewed by a European Federation of Societies for Ultrasound in Medicine and Biology position paper. However, the practical applications of this imaging technique were not included. This article reviews and discusses the published literature on the clinical use of dynamic contrast-enhanced US. This review finds that dynamic contrast-enhanced US imaging is the most sensitive cross-sectional real-time method for measuring the perfusion of parenchymatous organs noninvasively. It can measure parenchymal perfusion and therefore can differentiate between benign and malignant tumors. The most important routine clinical role of dynamic contrast-enhanced US is the prediction of tumor responses to chemotherapy within a very short time, shorter than using Response Evaluation Criteria in Solid Tumors criteria. Other applications found include quantifying the hepatic transit time, diabetic kidneys, transplant grafts, and Crohn disease. In addition, the problems involved in using dynamic contrast-enhanced US are discussed.

Diagnostic performance of contrast enhanced ultrasound in patients with prostate cancer: a meta-analysis

RATIONALE AND OBJECTIVES

We aimed to do a meta-analysis of the existing literature to assess the accuracy of prostate cancer (PCa) studies that use contrast-enhanced ultrasound (CEUS) as a diagnostic tool.

MATERIALS AND METHODS

The MEDLINE, EMBASE, and Cochrane Library databases were searched for relevant original articles published up to August 2012. Characteristics of Included studies were recorded. Methodological quality was assessed by using the quality assessment of diagnostic studies tool. Pooled weighted estimates of diagnostic odds ratio (DOR), sensitivity, specificity, and positive and negative likelihood ratio (LR) were calculated. A summary receiver operator characteristic (SROC) curve was constructed to calculate the area under the curve (AUC). Publication bias analysis was also performed.

RESULTS

Sixteen studies (2624 patients) were included in the meta-analysis. Various contrast agents and imaging modes were applied. The independent random-effects summary showed a variation in diagnostic values. The summary estimates of sensitivity, specificity, and DOR were 0.70, 0.74, and 9.09, respectively. The weighted positive and negative LR were 2.81 and 0.35, with statistically significant between-study heterogeneity (P < .001). Sensitivity was better in positive patient studies than positive biopsy cores ones (0.78 vs. 0.64). SROC plot displayed value for AUC (0.82). Begg's test (P = .822) and Egger's test (P = .198) did not show evidence of publication bias.

CONCLUSION

CEUS is a promising tool in the detection of PCa, but it cannot completely replace systematic biopsy under the present circumstances. It is necessary to standardize imaging techniques, contrast agents and diagnostic criteria. Large samples, multi-center studies and high-quality prospective trials are necessary to assess its clinical value.

Image guidance in the focal treatment of prostate cancer

PURPOSE OF REVIEW

The advent of prostate-specific antigen screening has led to a seven-fold increase in the incidence of prostate cancer without a resultant decrease in mortality rate. This has led to the belief that urologists are overdetecting and overtreating clinically insignificant disease. To maintain the delicate balance between high cancer cure rate and overtreatment, which could potentially lead to unnecessary morbidities, focal therapy has emerged as the reasonable middle ground. In this article, we present the conceptual basis and the challenges of focal therapy, while emphasizing the critical role of imaging in focal treatment of prostate cancer.

RECENT FINDINGS

Multiple phase I trials have demonstrated the feasibility, short-term efficacy, and safety of focal therapy. Fundamental to the success of these trials and the ultimate acceptance of focal therapy is the integral role of imaging in optimal patient selection. Among the different imaging modalities, only ultrasound and multiparametric MRI are intimately involved in the detection, diagnosis, staging, and treatment of prostate cancer. Each modality has its own unique advantages and shortcomings. Recent advances in enhanced ultrasound modalities, functional MRIs, and biopsy platforms have taken focal therapy one step closer to becoming the standard of care.

SUMMARY

Although early results of phase I focal therapy trials are encouraging, long-term oncological outcomes remain to be elucidated. Incorporation of these technological advances into large prospective trials is needed to establish focal therapy as an important asset in the urologist's armamentarium against prostate cancer.