Reproducibility of contrast-enhanced transrectal ultrasound of the prostate

Feasibility of dynamic 3-D color Doppler ultrasound for imaging penile vascular change in renal transplant patients with erectile dysfunction responding to sildenafil

Renal transplant recipients (RTRs) have a high incidence of erectile dysfunction (ED). Differentiation of penile vasculogenic impotence from other causes is important for treatment. Conventional 2-D color Doppler assessment after intracavernosal stimulant injection often fails to produce reliable results because of limited views by the cross-sectional imaging and the painful procedure. In comparison to the findings in three healthy volunteers, we determined cavernosal vascular hemodynamics in eight RTRs with ED before and after oral sildenafil by using live 3-D ultrasound and dynamic 3-D color Doppler. Results showed that, before sildenafil, penile arterial flow signals could only be reliably detected in one patient. After sildenafil, all had reliably detectable flow with grades II to III erection. Our data suggest that 3-D volumetric changes of the penis and its vasculature during erection can be studied by this technique and that this method could be useful for the evaluation of new drugs and therapeutic biofeedback.

Computer-aided diagnosis of prostate cancer with emphasis on ultrasound-based approaches: a review

This paper reviews the state of the art in computer-aided diagnosis of prostate cancer and focuses, in particular, on ultrasound-based techniques for detection of cancer in prostate tissue. The current standard procedure for diagnosis of prostate cancer, i.e., ultrasound-guided biopsy followed by histopathological analysis of tissue samples, is invasive and produces a high rate of false negatives resulting in the need for repeated trials. It is against these backdrops that the search for new methods to diagnose prostate cancer continues. Image-based approaches (such as MRI, ultrasound and elastography) represent a major research trend for diagnosis of prostate cancer. Due to the integration of ultrasound imaging in the current clinical procedure for detection of prostate cancer, we specifically provide a more detailed review of methodologies that use ultrasound RF-spectrum parameters, B-scan texture features and Doppler measures for prostate tissue characterization. We present current and future directions of research aimed at computer-aided detection of prostate cancer and conclude that ultrasound is likely to play an important role in the field.

Trends and future needs in clinical radiology: insights from an academic medical center

OBJECTIVE

Advances in technology, expanding indications and defensive medical practice, in combination with population aging, have all contributed to a substantial increase in utilization of imaging and therapeutic radiology procedures in recent years. Moreover, the integration of education, innovation and research into high-volume workflow, although challenging, is a key requirement in teaching hospitals. Therefore, identifying forthcoming demand in the use of radiology services at a referral center might be of special interest and facilitate health policy planning in this context.

METHODS

Data regarding conventional radiographic, ultrasonographic and computed tomography (CT) investigations, radiotherapy sessions, and interventional procedures were collected for a 5-year period (2000-2004). Based on these observations, we deployed appropriate models to forecast utilization rates in 2005-2009.

RESULTS

Between 2000 and 2004, ultrasound examinations increased by 31.8%, mammography by 31.6%, CT scans by 17.4%, interventions by 14.5% and radiotherapy sessions by 13.9%, while conventional investigations decreased by 42.5%. We identified significant increasing trends for ultrasound, mammography, CT and interventions (all p<0.001 for linear component). Compared to current levels, the workload for these modalities is expected to rise in the next 5 years by 43%, 31%, 20% and 14%, respectively. Radiotherapy sessions demonstrate an unstable, non-significant increasing trend (p=0.189), while utilization of conventional radiography declines rapidly (p<0.001 for linear trend, 5-year prediction -51%).

CONCLUSIONS

In forthcoming years, the demand for radiology services at referral centers will increase substantially. Advances in digital technology alone will not suffice to completely alleviate the need for additional resources and well-trained personnel.

Color and power Doppler sonography in the diagnosis of prostate cancer: comparison between vascular density and total vascularity

OBJECTIVE

Advances in color flow Doppler (CFD) and power Doppler imaging (PDI) have potential for prostate cancer diagnosis. Previous reports based on qualitative assessment suggest that hypervascularity increases likelihood of prostate cancer. Our objective was to compare 2 methods of vascularity assessment using PDI: total vascularity (TV) and vascular density (VD). The goal was to determine whether quantitative Doppler vascularity correlates with the likelihood of prostate cancer. Quantitative measurements were compared with subjective visual analysis of images.

METHODS

Ninety patients before biopsy had gray scale sonography, CFD, and PDI. Histologic analysis showed adenocarcinoma, prostate intraepithelial neoplasia, benign prostatic hypertrophy/prostatitis, and benign findings. The CFD and PDI images were analyzed for vascularity by (1) integrating the number of blood vessels over an imaged area (TV) and (2) integrating the number of vessels over a unit area of tissue (VD). Images were also assessed visually. VD, TV, and visual assessment were compared with one another and histologic findings.

RESULTS

Mean volume was not different. In each pathologic group, vascularity extent measured by TV and VD ranged from low to high. Disease groups did not exhibit a substantial difference in vascularity by either quantitative or qualitative analyses. Regionally, central gland TV was not significantly more vascular than peripheral gland TV except in benign prostatic hypertrophy. However, peripheral gland VD was 2.5 times greater than central gland VD. Seventy-one percent of the 31 focal hypoechoic lesions were hypervascular. Only 23% were carcinoma.

CONCLUSIONS

Pathologic categories were not separable by apparent vascular measurement. All pathologic categories showed low, moderate, or high vascularity; thus vascular areas by themselves did not distinguish cancer types, nor did focal hypervascular hypoechoic areas increase the likelihood of cancer. These imaging techniques provided no further resolution of tumor discrimination over multiple biopsies of the prostate.

Does the adjunct of ecographic contrast medium Levovist improve the detection rate of prostate cancer?

OBJECTIVES

To evaluate whether the adjunct of an ultrasound contrast medium improves the detection rate of prostate cancer.

METHOD

In 34 patients, scheduled to undergo a trans-perineal extended prostate biopsy, we carried out a color-Doppler ultrasound (CDU) of the prostate before and after i.v. injection of Levovist, an ultrasound contrast medium. Further bioptic samples were taken in the areas where a marked increase in vascularization was noticed.

RESULTS

The overall diagnostic sensitivity, specificity and efficiency were respectively 72.7, 56.2 and 62.9% for transrectal ultrasound (TRUS); 80, 56.2 and 65.3% for CDU and 88.8, 54.5 and 68% for CDU after Levovist injection; 66.5, 72.6 and 65.1% for digito-rectal examination (DRE); 100, 51.4 and 65.4% for total PSA; and 100, 88.8 and 94.3% for PSA free/total. In the 16 patients with prostate carcinoma, the sensitivity of CDU after Levovist was 92.3, 66% for both DRE and TRUS, and 80% for DRE plus TRUS.

CONCLUSIONS

Considering the cost and the results obtained (high sensitivity and low specificity), a routine use of Levovist does not seem indicated in patients undergoing prostatic biopsy. An exception may be represented by patients with both negative DRE and TRUS.

The value of dynamic contrast enhanced power Doppler ultrasound imaging in the localization of prostate cancer

OBJECTIVES

The objective of this study is to define enhancement characteristics that correlate to the presence of prostate cancer (PCa) and to evaluate the value of these characteristics in the localization of prostate cancer.

METHODS

29 patients with proven prostate malignancy, scheduled for radical prostatectomy, underwent an ultrasound examination prior to surgery. A bolus injection of contrast agent was administered intravenously. The distribution of the contrast enhanced blood to the prostate was monitored using Transrectal Contrast Enhanced Power Doppler Ultrasound. Fixed protocols and settings were used for all patients. The percentage of a selected area that showed enhancement was observed in time. The resulting enhancement curves were described using the parameters time to start, time to the maximum of the enhancement, the maximum value of the enhancement, and the rise time of the enhancement. Three evaluation-protocols divided the prostate into a number of areas of interest: into two areas using the Left-Right (LR) and Dorsal-Ventral (DV) protocols and into four areas using the Quadrant-protocol (Q). The enhancement parameters of the areas of interest were compared to identify the most affected area. The results were compared to the histopathological findings.

RESULTS

For the LR-protocol, the minimal time to peak proved to be the most predictive parameter for selecting the major malignant area. 78% of the patients were diagnosed correctly (N=23). Accurate localization of the major malignancy in either the ventral or dorsal side of the prostate was not feasible using the current protocol.

CONCLUSIONS

Malignancies can be accurately localized in either the left or the right side of the prostate based on the time to the maximum of the enhancement. An accurate discrimination between malignancies in either the dorsal or ventral side of the prostate cannot be performed. This is most likely due to anatomical differences between the dorsal and ventral area.

[Transrectal ultrasound of the prostate. Current status and prospects]

In recent years the role of ultrasound in the diagnosis of prostate carcinoma has increased in importance. In view of the increasing incidence of prostate cancer, which is the most frequent malignant neoplasm in men, TRUS (transrectal ultrasound) is an important imaging method in the diagnosis of various prostate diseases. This paper provides a basic overview of physical and technical bases of TRUS investigation of the prostate. It concerns technical developments and modern techniques designed to improve its value in diagnosis. Impressive innovations in ultrasound equipment, particularly in the area of colour-coded Doppler sonography in association with microbubble-enhanced colour Doppler ultrasound, have given rise to justifiable hope of improvements in the early diagnosis of prostate cancer.

Value of contrast ultrasonography in the detection of significant prostate cancer: correlation with radical prostatectomy specimens

BACKGROUND

The presented study has investigated a possible improvement of imaging prostate cancer: three-dimensional contrast-enhanced power Doppler ultrasonography (3D-CE-PDU).

METHODS

Seventy patients with biopsy proven prostate cancer and scheduled for radical retropubic prostatectomy received a 3D-CE-PDU investigation before surgery. Two experts analyzed the ultrasound images. The ultrasound images were correlated to the whole-mount sections of the prostate specimen. The correlation protocol consisted of three evaluation steps.

RESULTS

In total, 153 prostate tumors were found in the 70 prostate specimens: 61 tumors <5 mm, 93 tumors >or=5 mm. The diagnosis of clinical significant and insignificant prostate cancer was made in 85 and 88% of the patients for expert I and II, respectively. Diagnosis by imaging improved from 61% (43 of 70 of the prostate cancers) for standard detection tools to an average 86% (60 of 70 prostate cancers) for 3D-CE-PDU.

CONCLUSION

3D-CE-PDU improves the detection of prostate cancer in this group of prostate cancer patients. The use of 3D-CE-PDU in the clinic is questionable as indications are still unclear.