High-frequency Doppler US of the prostate: effect of patient position

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.

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.

Quantifying the effect of biopsy lateral decubitus patient positioning compared to supine prostate magnetic resonance image scanning on prostate translocation and distortion

INTRODUCTION

More than a quarter of tumors are missed by magnetic resonance imaging/ultrasound (MRI/US) fusion-guided biopsy, the majority due to software-based misregistration. Transrectal approaches to biopsy are typically performed in the lateral decubitus position; conversely, diagnostic MRI is performed with the patient lying supine. Any position-related difference in prostate location or gland deformation could potentially exacerbate misregistration at subsequent biopsy.

METHODS

Fifteen healthy male volunteers (mean age 35.9 years, range 27-53) were included in this prospective, institutional review board-approved study. Each volunteer had an MRI performed in the supine position, followed by the second in the lateral decubitus position (mimicking a typical biopsy position). MRI images were co-registered and analyzed in order to assess prostate translocation and distortion.

RESULTS

Whole prostate translocation of ≥5 mm was observed in 20% of patients and of ≥3 mm in 60% of patients. When dividing the prostate into prostatic sectors, the prostatic base demonstrated the largest positional difference. When plotting the translocation directions with relative volume difference, there was a moderate negative correlation trend in the latero-lateral direction. Only minimal distortion was observed, with similar distortion among all prostatic sectors.

CONCLUSIONS

Positional change affects the prostate translocation, however, the effect on prostate distortion appears to be negligible. Prostate translocation in latero-lateral direction can be minimized with larger bladder volumes. Prostate translocation needs to be considered alongside software misregistration error; however, positional change should not affect software registration of MRI/US fusion-guided prostate biopsy.

Evaluation of Prostatic Lesions by Transrectal Ultrasound, Color Doppler, and the Histopathological Correlation

Objective

To evaluate the role of a transrectal ultrasound (TRUS) guided biopsy and a color Doppler test in the detection of prostate cancer in patients with increased serum prostate-specific antigen (PSA) levels and/or an abnormal digital rectal examination (DRE).

Method

A total of 40 cases, ranging in age from 50 to 80 years and showing increased serum PSA levels (4-10 ng/ml) and/or abnormal DRE, were enrolled and underwent TRUS evaluation followed by color Doppler flowmetric studies. A TRUS-guided biopsy was performed in all the cases. The findings were confirmed histopathologically. Data were analyzed using the chi-square test.

Results

Histopathologically, a total of 13 cases (32.5%) were malignant. On TRUS, irregular shape, heterogeneous echotexture loss of differentiation between the peripheral and internal zones, less mean weight of the prostate, and capsular invasion were significantly associated with malignancy. On flowmetry, moderate vascularity and focal asymmetry were significantly associated with malignancy. The combined use of TRUS and color Doppler flowmetry was found to be 100% sensitive and 92.6% specific and had a positive predictive value (PPV) and a negative predictive value (NPV) of 86.7% and 100%, respectively.

Conclusion

TRUS with color Doppler flowmetry was highly sensitive and specific in the detection of prostate malignancy.

Association of Prostate Blood Flow with Male Lower Urinary Tract Symptoms

PURPOSE

To investigate the association of prostate blood flow (PBF) with lower urinary tract symptoms (LUTS) in aged males using Doppler spectral waveform (DSW) analysis.

PATIENTS AND METHODS

We performed a prospective analysis involving 133 aged males with clinical diagnosis of LUTS. DSW parameters (peak-systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI)) were measured at bilateral neurovascular bundles (NVB), periurethral, and capsular branches by Doppler transrectal ultrasound with the patient in the right lateral decubitus position. The associations of PBF parameters and the International Prostate Symptom Score (IPSS) were analyzed.

RESULTS

Overall, total IPSS scores were significantly correlated with the RI of bilateral NVB vessels (r2 = 0.03, 0.04; p = 0.04, 0.02, respectively), and PSV of left NVB vessels. PSV of bilateral NVB vessels were associated with the storage score (p = 0.022 and p = 0.016), but not with the voiding score. The sum of the frequency and urgency score was also associated with EDV of both capsular and urethral branches (p = 0.043 and p = 0.009, respectively), and PSV of NVB vessels on both sides (p = 0.045 and p = 0.019, respectively).

CONCLUSIONS

There is an association between PBF and LUTS, especially with storage symptoms. The findings may provide some insights in understanding the underlying pathophysiology of lower urinary tract dysfunction.

Prospective evaluation of prostate with transrectal spectral Doppler with biopsy correlation: a clinicopathologic study

OBJECTIVES

To compare the transrectal (TR) spectral Doppler findings between benign prostatic hyperplasia group and prostate cancer group.

METHODS

All the patients were assessed for adequate preparation, and informed consent was obtained prior to the procedure. The control group (n = 33) comprised patients who were negative for malignancy on biopsy. The study group (n = 22) were positive for malignancy and were also divided into three groups on the basis of the Gleason score. Study parameters included mean values for resistive index (RI), pulsatality index (PI), systolic/diastolic ratio (S/D) and peak systolic velocity (PSV). These were separately measured for bilateral capsular and urethral branches and compared between groups. In patients with unilateral tumour, these were compared between the tumour and non-tumour sides. Finally, the parameters were compared with patient's age. Mann-Whitney U test was used to evaluate the statistical significance.

RESULTS

The mean values of RI, PI, S/D and PSV were found to be 0.84/1.03, 1.8/1.99, 3.93/4.45 and 15.52/16.15 cm s(-1), respectively, in the control and study groups which were not statistically significant. In patients with unilateral malignancy (n = 16), there was no significant difference from the non-tumour side. Doppler parameters showed statistically significant relationships with age. The mean of minimum RI was found to be 0.60 in patients less than 60 years of age and 0.76 in patients more than or equal to 60 years of age in the benign category (p-value = 0.014). The PI and S/D also showed significant difference in the benign category.

CONCLUSION

TR spectral Doppler parameters did not reveal any significant difference in patients with or without prostatic malignancy, irrespective of the Gleason grade. Doppler parameters, however, showed significant correlation with age and were lower in younger patients.

ADVANCES IN KNOWLEDGE

TR spectral Doppler is unlikely to emerge as a diagnostic and prognostic tool for prostate carcinoma.

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.

Cysts of the lower male genitourinary tract: embryologic and anatomic considerations and differential diagnosis

Cysts of the lower male genitourinary tract are uncommon and usually benign. These cysts have different anatomic origins and may be associated with a variety of genitourinary abnormalities and symptoms. Various complications may be associated with these cysts, such as urinary tract infection, pain, postvoiding incontinence, recurrent epididymitis, prostatitis, and hematospermia, and they may cause infertility. Understanding the embryologic development and normal anatomy of the lower male genitourinary tract can be helpful in evaluating these cysts and in tailoring an approach for developing a differential diagnosis. There are two main groups of cysts of the lower male genitourinary tract: intraprostatic cysts and extraprostatic cysts. Intraprostatic cysts can be further classified into median cysts (prostatic utricle cysts, müllerian duct cysts), paramedian cysts (ejaculatory duct cysts), and lateral cysts (prostatic retention cysts, cystic degeneration of benign prostatic hypertrophy, cysts associated with tumors, prostatic abscess). Extraprostatic cysts include cysts of the seminal vesicle, vas deferens, and Cowper duct. A variety of pathologic conditions can mimic these types of cysts, including ureterocele, defect resulting from transurethral resection of the prostate gland, bladder diverticulum, and hydroureter and ectopic insertion of ureter. Accurate diagnosis depends mainly on the anatomic location of the cyst. Magnetic resonance imaging and transrectal ultrasonography (US) are excellent for detecting and characterizing the nature and exact anatomic origin of these cysts. In addition, transrectal US can play an important therapeutic role in the management of cyst drainage and aspiration, as in cases of prostatic abscess.

Multiparametric ultrasound of the prostate: adding contrast enhanced ultrasound to real-time elastography to detect histopathologically confirmed cancer

PURPOSE

We prospectively assessed whether a combined approach of real-time elastography and contrast enhanced ultrasound would improve prostate cancer visualization.

MATERIAL AND METHODS

Between June 2011 and January 2012, 100 patients with biopsy proven prostate cancer underwent preoperative transrectal multiparametric ultrasound combining real-time elastography and contrast enhanced ultrasound. After initial elastographic screening for suspicious lesions, defined as blue areas with decreased tissue strain, each lesion was allocated to the corresponding prostate sector. The target lesion was defined as the largest cancer suspicious area. Perfusion was monitored after intravenous injection of contrast agent. Target lesions were examined for hypoperfusion, normoperfusion or hyperperfusion. Imaging results were correlated with final pathological evaluation on whole mount slides after radical prostatectomy.

RESULTS

Of 100 patients 86 were eligible for final analysis. Real-time elastography detected prostate cancer with 49% sensitivity and 73.6% specificity. Histopathology confirmed malignancy in 56 of the 86 target lesions (65.1%). Of these 56 lesions 52 (92.9%) showed suspicious perfusion, including hypoperfusion in 48.2% and hyperperfusion in 48.2%, while only 4 (7.1%) showed normal perfusion patterns (p = 0.001). The multiparametric approach decreased the false-positive value of real-time elastography alone from 34.9% to 10.3% and improved the positive predictive value of cancer detection from 65.1% to 89.7%.

CONCLUSIONS

Perfusion patterns of prostate cancer suspicious elastographic lesions are heterogeneous. However, the combined approach of real-time elastography and contrast enhanced ultrasound in this pilot study significantly decreased false-positive results and improved the positive predictive value of correctly identifying histopathological cancer.

Contrast enhanced transrectal ultrasound for the detection of prostate cancer: a randomized, double-blind trial of dutasteride pretreatment

PURPOSE

The identification of clinically significant disease is crucial for optimal treatment of prostate cancer. Selective detection of prostate cancer with increased microvessel density is possible with contrast enhanced ultrasound. Preliminary studies suggest that pretreatment with a 5α-reductase inhibitor may improve the efficiency of contrast enhanced ultrasound targeted biopsy. This study was designed to quantify prostate cancer detection with contrast enhanced ultrasound with or without short-term pretreatment with dutasteride.

MATERIALS AND METHODS

In this randomized, double-blind, placebo controlled trial of oral dutasteride pretreatment, contrast enhanced ultrasound findings were graded and used to direct targeted biopsy (up to 6 cores per prostate). A blinded 12-core systematic biopsy was subsequently performed on every subject based on standard medial and lateral sampling of each sextant.

RESULTS

Of 311 subjects who underwent randomization, 272 completed participation. Positive biopsies were obtained in 276 of 3,264 (8.5%) systematic cores and 203 of 1,237 (16.4%) targeted cores (OR 2.1, 95% CI 1.7-2.6, p <0.001). ROC analysis for the detection of all prostate cancers demonstrated an increase in diagnostic accuracy from pre-contrast imaging to contrast enhanced ultrasound (A(z) 0.60 vs 0.64, p = 0.005). For the detection of high grade cancer (Gleason score 7 or greater) ROC analysis demonstrated improved accuracy for pre-contrast imaging (A(z) 0.74) and contrast enhanced ultrasound (A(z) 0.80, p = 0.0005). For the detection of high grade cancer with greater than 50% biopsy core involvement, excellent accuracy was demonstrated with pre-contrast and contrast enhanced ultrasound, A(z) 0.83 and 0.90, respectively (p = 0.001). Pretreatment with dutasteride had no significant impact on the detection of prostate cancer (p = 0.97).

CONCLUSIONS

Contrast enhanced ultrasound targeted biopsy provides a significant benefit for the detection of high grade/high volume prostate cancer.

Application of ultrasonography and the resistive index for evaluating bladder outlet obstruction in patients with benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is an extremely common and chronic condition that can lead to bladder outlet obstruction (BOO) in elderly men. Although pressure-flow studies are considered the most reliable method for evaluating BOO, they are invasive and complicated. Transrectal ultrasonography (TRUS) is a promising alternative because of its minimal invasiveness. Recently, TRUS imaging has been shown capable of measuring the resistive index, a useful parameter for evaluating BOO and for determining proper medical intervention in patients suffering from BPH.

Correlations among cardiovascular risk factors, prostate blood flow, and prostate volume in patients with clinical benign prostatic hyperplasia

OBJECTIVE

To investigate the relationships among the cardiovascular risk factors, prostate blood flow, and prostate volume in patients with clinical benign prostatic hyperplasia (BPH).

METHODS

A total of 130 patients with the clinical diagnosis of BPH were recruited. The presence of 5 cardiovascular risk factors, including obesity, diabetes, hypertension, hyperlipidemia, and a history of cardiovascular events, was recorded. The urologic evaluation included digital rectal examination, serum prostate-specific antigen, International Prostate Symptom Score, and transrectal ultrasonography. Doppler spectrum analysis was performed with the patient in the right lateral decubitus position to measure the blood flow in the prostate capsular arteries, periurethral arteries, and neurovascular bundles. The correlations were analyzed between the resistive indexes of the prostatic branches and the cardiovascular risk factors, as well as the transrectal ultrasound findings.

RESULTS

The resistive indexes of the periurethral arteries and right neurovascular bundles showed positive correlations with the number of cardiovascular risk factors in the patients (r=.228, P=.01 and r=.225, P=.011, respectively). The periurethral artery resistive index also correlated positively with both prostate and transitional zone volumes, with the capsular artery correlating positively only with the latter. No significant correlations were noted between the resistive indexes and the International Prostate Symptom Score.

CONCLUSION

Prostate vascular resistance in patients with BPH has positive correlations with cardiovascular risk factors and prostate size. These findings suggest that prostate hypoxia might play a role in the pathogenesis of BPH.

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.

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 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.

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.

Effect of Dutasteride Therapy on Doppler US Evaluation of Prostate: Preliminary Results

PURPOSE

To prospectively determine the effect of short-term therapy with dutasteride on the suppression of Doppler ultrasonographic (US) signal in benign prostate tissue and thus on improvement in the depiction of prostate cancer with Doppler US-guided core-needle biopsy.

MATERIALS AND METHODS

After institutional review board approval and informed consent were obtained as part of this HIPAA-compliant study, 11 men (age range, 59-77 years) were evaluated with gray-scale, color, and power Doppler US at baseline and weekly for up to 3 weeks while taking 0.5 mg of dutasteride per day. Flow intensity in the periurethral, transition, and peripheral zones was subjectively scored by using a four-point scale. The Wilcoxon matched-pairs signed-ranks test was used to compare pre- and posttherapy scores. After flow was reduced to "diminished" or "none" with at least a 1-score difference on the four-point scale, up to four targeted cores were obtained from areas of persistent flow within the peripheral zone, followed by laterally directed sextant biopsy.

RESULTS

Doppler US flow suppression occurred in 11 of 11 patients after 1 week of dutasteride therapy (P < .01). Further suppression was noted after 2 weeks in eight of 10 patients (P = .04) and after 3 weeks in two of two patients. Biopsy was performed after 1 (n = 1), 2 (n = 8), or 3 (n = 2) weeks of therapy. Flow suppression was greatest in the peripheral zones (mean decrease: 0.64 and 0.76 after weeks 1 and 2, respectively) and least in the periurethral zones (mean decrease: 0.30 after 1 week). Cancer was detected in eight (20%) of 40 targeted cores and in five (8%) of 66 sextant cores. Four patients had cancer at targeted biopsy, and three of these four patients had cancer at sextant biopsy. In the four men with cancer, targeted cores were 5.9 times more likely to be positive (P = .027). Selective suppression of flow in benign tissue was observed in two of the four men with cancer.

CONCLUSION

Short-term dutasteride therapy reduces Doppler US flow in the prostate and may improve depiction of hypervascular cancer.

Detection of prostate carcinoma with contrast-enhanced sonography using intermittent harmonic imaging

BACKGROUND

The purpose of this study was to assess prostate carcinoma detection and discrimination of benign from malignant prostate tissue with contrast-enhanced ultrasonography.

METHODS

In all, 301 subjects referred for prostate biopsy were evaluated with contrast-enhanced sonography using continuous harmonic imaging (CHI) and intermittent harmonic imaging (IHI) with interscan delay times of 0.2, 0.5, 1.0, 2.0 seconds, as well as continuous color and power Doppler. Targeted biopsy cores were obtained from sites of greatest enhancement, followed by spatially distributed cores in a modified sextant distribution.

RESULTS

Carcinoma was detected in 363 biopsy cores from 104 of 301 subjects (35%). Carcinoma was found in 15.5% (175 of 1133) of targeted cores and 10.4% (188 of 1806) of sextant cores (P < 0.01). Among subjects with carcinoma, targeted cores were twice as likely to be positive (odds ratio [OR] = 2.0, P < 0.001). Clustered receiver operating characteristic (ROC) analysis of imaging findings at sextant biopsy sites yielded the following Az values: precontrast gray scale: 0.58; precontrast color Doppler: 0.53; precontrast power Doppler: 0.58; CHI: 0.62; IHI (0.2 sec): 0.64; IHI (0.5 sec): 0.63; IHI (1.0 sec): 0.65; IHI (2.0 sec): 0.61; contrast-enhanced color Doppler: 0.60; contrast-enhanced power Doppler: 0.62. A statistically significant benefit was found for IHI over baseline imaging (P < 0.05).

CONCLUSIONS

The carcinoma detection rate of contrast-enhanced targeted cores is significantly higher when compared with sextant cores. Contrast-enhanced transrectal sonography with IHI provides a statistically significant improvement in discrimination between benign and malignant biopsy sites. However, given the relatively low ROC areas, this technique may not be sufficient to predict which patients have benign versus malignant disease.

MR-guided transgluteal biopsies with an open low-field system in patients with clinically suspected prostate cancer: technique and preliminary results

The purpose of this study was to examine the feasibility and safety of MR-guided biopsies with a transgluteal approach in patients with uncertain or suspicious prostate lesions. Twenty-five patients with uncertain or suspicious focal prostate lesions detected by high-field MR imaging of the prostate gland using endorectal coil imaging were biopsied with a transgluteal approach in a low-field MRI system (0.2 T, Concerto, Siemens). The procedures were guided using T1-weighted FLASH sequences. The prostate gland was biopsied repeatedly with a coaxial technique through a 15-gauge pencil tip with a 16-gauge biopsy handy (median 3.8 samples per patient). Complications and biopsy findings were documented retrospectively. Using T1-weighted sequences biopsy procedures were performed successfully with MR guidance in all cases without any side effects or complications. The median intervention time was 11.3 min. Pathological findings revealed ten cases of hyperplasia or atrophy, three cases of prostatitis, ten cases of carcinoma and two cases of normal tissue. The clinical follow-up showed that in two patients prostate cancer was missed at MR-guided biopsy. Transgluteal MR-guided biopsy of the prostate gland is a safe and promising approach for histological clarification of uncertain or suspicious lesions.

Can color doppler predict the uniformity of HIFU-induced prostate tissue destruction?

BACKGROUND

Tissue blood perfusion influences the results of some hyperthermia and thermotherapy procedures, but its role in the outcome of prostate cancer treatment by high-intensity focused ultrasound (HIFU) has not been evaluated yet. We evaluated preoperative prostate color Doppler as a predictor of the efficacy of HIFU treatment.

METHODS

Thirty-five patients underwent pre- and post-contrast color Doppler examination of the prostate before HIFU treatment. Specific software was used to calculate, on color Doppler images, the color pixel density (CPD), and the specific flow (SF, i.e., mean velocity x CPD) in different regions of interest. Post-treatment sextant biopsies were obtained in 31 patients, 5.8 +/- 2.8 months after HIFU treatment.

RESULTS

No significant correlation was found between the uniformity of HIFU-induced tissue destruction observed on control biopsies and the pre-treatment CPD/SF values in any region of interest, either before or after contrast injection. On the other hand, history of radiation therapy was significantly associated with homogeneous tissue destruction and history of hormone therapy was significantly associated with incomplete tissue destruction.

CONCLUSIONS

Color Doppler cannot predict the uniformity of HIFU-induced tissue destruction. History of radiation therapy was found to be a factor of favorable prognosis and history of hormone therapy was found to be a factor of poor prognosis in our population.

Optimal combinations for detection of prostate cancer: systematic sextant and laterally directed biopsies versus systematic sextant and color doppler-targeted biopsies

OBJECTIVES

To determine the accuracy of different combinations of biopsies in detecting prostate cancer. The standard sextant protocol for obtaining prostate biopsy underestimates the presence of prostate cancer. Conversely, an increased cancer detection rate has been obtained with additional laterally directed biopsies. The results of the studies dedicated to transrectal color Doppler (CD) sonography have shown that it might detect neoplastic lesions with no corresponding gray-scale abnormality.

METHODS

A total of 120 consecutive patients underwent sextant biopsy with additional biopsy cores taken from the lateral peripheral zone (four to six cores, depending on the prostate volume) and CD-guided biopsy. The sensitivity of laterally directed, CD-guided, and different combinations of biopsies was compared. Various patient, clinical, and pathologic factors were compared, and multivariate analysis was performed to assess the strongest predictor of cancer detection.

RESULTS

Cancer was detected in 43 (35.8%) of 120 patients. The combination of sextant biopsy with laterally directed cores gained sensitivity to 56.6% compared with 67.4% obtained in the regimen that combined sextant and CD-guided biopsy. The CD regimen detected cancer in 11 additional patients. However, the differences in the detection rates of these combinations were not statistically significant (P = 0.797). The results of multivariate analysis showed that sextant biopsy and laterally directed cores were the strongest predictors of cancer detection (odds ratio 8.356 versus 49.282; 95% confidence interval 1.698 to 41.114 versus 10.508 to 231.130).

CONCLUSIONS

The regimen that included sextant and CD-guided biopsy was the most sensitive. However, only standard sextant and laterally directed biopsies were statistically significant predictors of cancer detection on biopsy.

Correlation between Doppler vascular density and PSA response to radiation therapy in patients with localized prostate carcinoma

RATIONALE AND OBJECTIVES

The authors performed this study to ascertain whether there is a correlation between pretreatment Doppler vascular density (DVD) of the prostate and prostate-specific antigen (PSA) response following radiation therapy in prostate cancer patients.

MATERIALS AND METHODS

Prior to radiation therapy, 14 patients with biopsy-proven carcinoma (of Gleason grades 2-7) were imaged with transrectal ultrasound in gray-scale, color Doppler, and power Doppler modes. The Doppler images were analyzed for mean DVD with the aid of a computer program. PSA levels were measured before therapy and every 3 months after therapy. The PSA measurements were fitted to an exponential to determine PSA halving time (T1/2). Correlations were made between T1/2 and the following pretherapy measurements: mean DVD, PSA level, prostate volume, and Gleason grade.

RESULTS

Median follow-up time was 392 days. A linear correlation with regression coefficient (R) of 0.75-0.80 was observed between mean DVD and T1/2 for color Doppler and power Doppler imaging. In both imaging modes, each percentage increase in mean DVD led to an increase in T1/2 by 25 days. Pretherapy prostate volume, PSA level, and Gleason score did not correlate with T1/2.

CONCLUSION

The pretreatment mean DVD correlates inversely with the rate of posttherapy decline in PSA in patients with prostate cancer. That is, pretreatment vascularity prognosticates postirradiation PSA response. The mechanism underlying this correlative relationship is not known.

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.

Prostate: high-frequency Doppler US imaging for cancer detection

PURPOSE

To evaluate cancer detection with targeted biopsy of the prostate performed on the basis of high-frequency Doppler ultrasonographic (US) imaging findings versus cancer detection with a modified sextant biopsy approach with laterally directed cores.

MATERIALS AND METHODS

Sixty-two patients were prospectively evaluated with gray-scale, color, and power Doppler transrectal US performed with patients in the lithotomy position. Gray-scale and Doppler findings within each sextant were rated on a five-point scale. Up to four targeted biopsy specimens were obtained from each patient on the basis of Doppler findings; this was followed by a modified sextant biopsy. Conditional logistic regression analysis was performed to compare the positive yields for targeted and sextant biopsy specimens. Clustered receiver operating characteristic analysis was performed to compare gray-scale, color, and power Doppler detection of cancer at sextant biopsy sites.

RESULTS

Cancer was detected in 18 (29%) of 62 patients, including 11 patients in whom cancer was detected with both sextant and targeted biopsy, six in whom cancer was detected only with sextant biopsy, and one in whom cancer was detected only with targeted biopsy. The positive biopsy rate for targeted biopsy (24 [13%] of 185 cores) was slightly higher than that for sextant biopsy (36 [9.7%] of 372 cores; P =.1). The odds ratio for cancer detection with targeted versus sextant cores was 1.8 (95% CI: 0.9, 3.7). Receiver operating characteristic analysis demonstrated that overall identification of positive sextant biopsy sites was close to random chance for gray-scale (area under the curve, 0.53), color Doppler (area under the curve, 0.50), and power Doppler (area under the curve, 0.47) imaging.

CONCLUSION

Targeted biopsy performed on the basis of high-frequency color or power Doppler findings will miss a substantial number of cancers detected with sextant biopsy.