The role of color Doppler and staging biopsies in prostate cancer detection

Endorectal multiparametric 3-tesla magnetic resonance imaging associated with systematic cognitive biopsies does not increase prostate cancer detection rate: a randomized prospective trial

PURPOSE

To investigate prostate cancer (PC) detection rate, employing endorectal multiparametric 3-tesla magnetic resonance imaging (MRI) driving subsequent cognitive systematic prostatic biopsy (CSPB) versus a homogenous group of patients who did not undergo endorectal MRI.

MATERIALS AND METHODS

A series of patients with a first negative biopsy were enrolled in the study. Patients were randomized into two groups: Group A: patients underwent MRI and subsequent CSPB; Group B: patients that did not undergo MRI. Each patient underwent a 13-core sampling. Patients from Group A had four cores more for each MRI suspected lesion. The cancer detection rate was calculated for each group with regard to possible matches or mismatches between MRI evidence and pathological reports.

RESULTS

Two hundred consecutive patients were investigated. Fifty out of 200 (25 %) patients had a diagnosis of PC, 24 in Group A and 26 in Group B. In Group A, 67 patients (67 %) were positive for suspected lesions at the MRI. The mismatch between MRI findings and the CSPB outcome was 61 % with an MRI-driven detection rate of 15 %. Group B detection rate was 26 % with no significant differences versus Group A (P = NS). Patient discomfort was higher in Group A (82 %). The accuracy of CSPB was 41 % with a positive predictive value of 22.3 %. This rate is lower in high-grade cancers (11.9 %). The cost-effectiveness was higher in Group A.

CONCLUSIONS

Prostate cancer detection rate does not improve by CSPB. The accuracy of CSPB was lower in high-grade PC, and a higher cost was found with CSPB.

Quantitative iodine-based material decomposition images with spectral CT imaging for differentiating prostatic carcinoma from benign prostatic hyperplasia

RATIONALE AND OBJECTIVES

To investigate the value of iodine-based material decomposition images produced via spectral computed tomography (CT) in differentiating prostate cancer (PCa) from benign prostate hyperplasia (BPH).

MATERIALS AND METHODS

Fifty-six male patients underwent CT examination with spectral imaging during arterial phase (AP), venous phase (VP), and parenchymal phase (PP) of enhancement. Iodine concentrations of lesions were measured and normalized to that of the obturator internus muscle. Lesion CT values at 75 keV (corresponding to the energy of polychromatic images at 120 kVp) were measured and also normalized; their differences between AP and VP, VP and PP, and PP and AP were also obtained. The two-sample t-test was performed for comparisons. A receiver operating characteristic curve was generated to establish the threshold for normalized iodine concentration (NIC).

RESULTS

Fifty-two peripheral lesions were found, which were confirmed by biopsy as 28 cases of PCa and 24 BPHs. The NICs of prostate cancers significantly differed from those of the BPHs: 2.38 ± 1.72 compared with 1.21 ± 0.72 in AP, respectively, and 2.67 ± 0.61 compared with 2.27 ± 0.77 in VP. Receiver operating characteristic analysis indicated that an NIC of 1.24 in the AP provided a sensitivity of 88% and a specificity of 71% for differentiating PCa from BPH.

CONCLUSIONS

Spectral CT imaging enabled quantitative depiction of contrast medium uptake in prostatic lesions and improved sensitivity and specificity for differentiating PCa from BPH.

Écho-Doppler et cancer de la prostate: option ou nécessité ?

PURPOSE

To evaluate the value of power Doppler sonography (PDS) in patients with a serum PSA level greater than 3.5 ng/ml and note the advantages of PDS in management of biopsy cores and staging in prostate cancer.

MATERIAL AND METHODS

A group of 579 patients with a serum PSA level greater than 3.5 ng/ml underwent sextant biopsies. PDS of the prostate was performed in all patients before biopsy indication. Patients underwent six initial sextant biopsies without Doppler. In 141 patients who retained an elevated serum PSA level, an additional series of six to eight ultrasound-guided biopsies with Doppler were indicated. A total of 299 cancers were diagnosed (126 palpable) after initial biopsies and 85 (13 palpable) after additional biopsies. One hundred seven patients with localized cancer (48 palpable) underwent a radical prostatectomy.

RESULTS

An echographic or vascular anomaly was detected in 335 patients; after biopsies this anomaly corresponded to 260 cancers, 39 of which were not visible (false-negative Doppler results). The negative predictive value was 84% and there was no significant relation between PSA level and negative predictive value. After initial biopsies, if an abnormal Doppler signal was present the risk of having positive additional biopsies was 83%. Abnormal disoriented irregular vessels were present in 69% of patients with a Gleason score of 7 or higher versus 31% in patients with a Gleason score less than 7 (p<0.01). Twenty out of 39 patients with T1c cancer invisible with PDS and not palpable (13% of all cancers) underwent a radical prostatectomy. Eleven of 16 cancers with a Gleason score of 6 or less were found insignificant, but in two cases the lesion was advanced (p<0.01). Of cancers with a tumor vessel crossing the capsule, 71% presented an extraprostatic extension (Se: 37.5%, Spe: 93%, PPV: 71%, NPV: 78%) (p<0.01).

CONCLUSION

In prostatic cancer, PDS allows evaluation of aggressiveness features and can optimize the number of useful biopsy cores.

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.

Hematospermia: imaging findings

Hematospermia is an anxiety provoking but otherwise generally benign and self-limited condition that is infrequently associated with significant underlying pathology, and is most often considered to be idiopathic in nature. Management with routine clinical evaluation, watchful waiting, and reassurance generally suffice without further diagnostic workup or treatment. Noninvasive imaging may play an important role in the diagnostic workup of men with hematospermia, particularly in those who are >40 years old, have other associated symptoms or signs of disease, or have persistence of hematospermia. Many entities may be encountered in association with hematospermia at imaging, and specific therapeutic interventions may be used if certain treatable underlying pathologies are coincidentally detected. In this comprehensive review, we discuss the potential etiologies, diagnostic workup, imaging techniques, relevant male pelvic anatomy, imaging appearance of specific associated pathologies, and treatment for hematospermia.

PROSTATE CANCER DETECTION IN MEN WITH PROSTATE SPECIFIC ANTIGEN 4 TO 10 NG/ML USING A COMBINED APPROACH OF CONTRAST ENHANCED COLOR DOPPLER TARGETED AND SYSTEMATIC BIOPSY

PURPOSE

Transrectal gray scale ultrasound guided biopsy is the standard method for diagnosing prostate cancer (PC). Improved cancer detection with ultrasound contrast agents is related to better detection of tumor vascularity. We evaluated the impact of a combined approach of contrast enhanced, color Doppler targeted biopsy (CECD) and systematic biopsy (SB) for the PC detection rate in men with prostate specific antigen (PSA) 4.0 to 10 ng/ml.

MATERIALS AND METHODS

We examined 380 screening volunteers with a total PSA of 4.0 to 10 ng/ml (percent free PSA less than 18). CECD was always performed before SB. Another investigator blinded to contrast enhanced findings performed 10 SBs. The cancer detection rate for the CECD, SB and combined approaches was assessed.

RESULTS

PC was detected in 143 of 380 patients (37.6%, mean total PSA 6.2 ng/ml). The PC detection rate for CECD and for SB was 27.4% and 27.6%, respectively. The overall cancer detection rate with the 2 methods combined was 37.6%. For targeted biopsy cores the detection rate was significantly better than for SB cores (32.6% vs 17.9%, p <0.01). CECD in a patient with cancer was 3.1-fold more likely to detect PC than SB.

CONCLUSIONS

CECD allows for the detection of lesions that cannot be found on gray scale ultrasound or SB. CECD allows for assessment of neovascularity associated with PC. However, the combined use of CECD and SB allows for maximal detection of PC with a detection rate of 37.6% in our patients with PSA 4 to 10 ng/ml.

Contrast specific imaging in the detection and localization of prostate cancer

Prostate cancer (PCa) is the most common cancer in elderly men and is one of the most important causes of death from cancer in men. The diagnosis of PCa is based on a combination of digital rectal examination, PSA and transrectal ultrasound (TRUS). However, this combination does not reach the accuracy of detection and localization necessary for proper decisions on treatment methods. Therefore, biopsies are performed in all cases for which the suspicion of PCa is raised. Even with biopsies, staging and grading of PCa is far from optimal. More accurate imaging is necessary to improve the biopsy sampling, the goals being to replace systematic biopsies by a targeted approach and to improve staging and grading of PCa. Ultrasound imaging of the prostate remains the first choice of imaging to visualize the prostate, however, gray-scale ultrasound imaging has an accuracy of about 50-60% for the detection of PCa and TRUS used for local staging has an even lower accuracy. The development of PCa is associated with changes in the metabolism of tumor cells, and therefore with changes in the blood perfusion of the involved tissue. This paper focuses on contrast specific imaging techniques to visualize these changes in blood perfusion. Techniques such as color and power Doppler imaging, and contrast enhanced imaging techniques using color and power Doppler, harmonic imaging and intermittent imaging are discussed.

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.

Transrectal colour Doppler ultrasonography for quantifying angiogenesis in prostate cancer

OBJECTIVE

To assess the correlation between angiogenesis and Doppler signal intensity using transrectal colour Doppler ultrasonography (CDUS) in patients with prostate cancer.

PATIENTS AND METHODS

The study comprised 56 patients who underwent radical prostatectomy and had untreated tumours with a volume of> 0.1 mL in the peripheral zone. CDUS images were recorded on videotape before surgery. The Doppler signal intensity in tumours was evaluated using the colour pixel intensity (PI). Microvessel density (MVD) and vascular endothelial growth factor (VEGF) immunoreactivity were determined in the prostatectomy specimens. Microvessels were identified by immunohistochemical staining of endothelial cells for CD31.

RESULTS

The PI in the tumour correlated with MVD (P < 0.001) and increased with higher levels of VEGF immunoreactivity (P = 0.004). There was no correlation between Gleason score and MVD or PI in the tumour.

CONCLUSION

Blood flow assessed by CDUS may reflect the state of angiogenesis in prostate cancer. CDUS may be a useful technique for predicting tumour progression or prognosis, and may be useful for monitoring the effects of anti-angiogenic agents in the future.

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.

Assessing the vascular-stromal coefficient in patients with benign prostatic hyperplasia or prostate cancer using transrectal ultrasonography and power Doppler analysis

OBJECTIVES

To assess a coefficient of the prostatic blood supply in patients with prostate cancer or benign prostatic hyperplasia (BPH), and thus improve the diagnostic and prognostic variables needed to evaluate patients with prostate cancer.

PATIENTS AND METHODS

The vascular-stromal coefficient was defined as the ratio of the blood vessel surface area and the surface area of the prostate, using power Doppler functions and transrectal ultrasonography. The index was calculated for the plane of the prostatic surface from the apex to the widest points of the peripheral zone, and for the plane across the highest density of blood vessels in the transition zone. A micobubble contrast agent was used to intensify the acoustic signals from prostatic vessels. The images were reconstructed in three dimensions. In all, 61 patients with BPH and 32 with confirmed prostate cancer were examined, and compared with a control group of young men.

RESULTS

In the horizontal plane crossing the apex of the prostate, the vascular-stromal coefficient was 0.0054 for the controls, 0.0072 for BPH and 0.0067 for cancer. At the level of the highest density of blood vessels the respective values were 0.0083, 0.038 and 0.029. The respective values for the first plane after using the contrast agent were 0.025, 0.092 and 0.0365, and in the second level 0.04, 0.15 and 0.14.

CONCLUSION

The vascular-stromal coefficient measured at both levels was higher in patients with BPH than in those with cancer or than in the controls. The prostatic vascular system can be computer-reconstructed in three dimensions, allowing an evaluation of asymmetry and other vascular abnormalities. The contrast agent effectively increases the vascular acoustic signals from the prostate, enhancing by a factor of five the visualization of blood vessels when using the power Doppler option.

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

PURPOSE

To evaluate cancer detection with directed biopsy of the prostate on the basis of high-frequency Doppler ultrasonographic (US) findings, and to determine the effect of patient position on the observed flow pattern.

MATERIALS AND METHODS

Thirty-two patients were evaluated in the left lateral decubitus position with gray-scale, color Doppler, and power Doppler transrectal US. Up to four directed biopsy specimens were obtained on the basis of gray-scale and Doppler US findings, and modified sextant biopsy followed. Analysis of variance and the Wilcoxon signed rank test were used to evaluate the distribution of Doppler signals within the prostate. Three healthy volunteers with no known prostate disease were also examined in supine and both decubitus positions.

RESULTS

In the patient group, both color and power Doppler US demonstrated increased flow on the left side of the prostate, with greater flow toward the base of the gland (P <.002). Consequently, 62 of 90 directed-biopsy cores were obtained in the left base and mid-gland. The positive biopsy rate for directed biopsy was not significantly different from that of sextant biopsy (P =.4). Seven patients had cancer that was identified with sextant biopsy, but only four cancers were identified with directed biopsy. Each of the three healthy volunteers demonstrated increased Doppler flow on the dependent side when the subject was in the lateral decubitus position.

CONCLUSION

The positive yield of directed biopsy was similar to the yield of sextant biopsy. On the basis of observations made in healthy volunteers, the authors conclude that flow asymmetry in patients who underwent biopsy may have been related to patient position.

Characteristics of normal prostate vascular anatomy as displayed by power Doppler

BACKGROUND

To define the vascular anatomy of the normal prostate as depicted by power Doppler and to provide baseline data for evaluation of this modality in the diagnosis and management of prostatic disease.

METHODS

The vascular anatomy of 40 subjects was studied. Power Doppler images were correlated with corresponding gray-scale images. Doppler spectral waveform measurements were obtained for the vessels identified.

RESULTS

Separate branches of the capsular vessels were visualized clearly, distributed radially in the peripheral and central zones and converging toward the center of the gland. Urethral vessels were visualized in the transition zone coursing from bladder neck to verumontanum. The neurovascular bundles were identified posterolaterally along the length of the gland. No significant difference between the resistive indexes of the urethral and capsular vessels was identified (P = 0.595), although there was a significant difference between the resistive index of the neurovascular bundles and that the prostatic vessels (P < 0.001).

CONCLUSIONS

The vascular anatomy of the normal prostate as displayed by power Doppler demonstrates a reproducible and symmetric flow pattern. Power Doppler is highly sensitive in depicting blood flow, the number, course, and continuity of vessels more readily than other imaging modalities, such as color Doppler. These data should allow comparison of the vascular anatomy of the normal prostate with that of the prostate with diseases such as prostate cancer and benign prostatic hyperplasia.

The role of colour Doppler ultrasonography in detecting prostate cancer

OBJECTIVE

To determine the usefulness of colour Doppler ultrasonography (CDUS) in detecting prostate cancer, by comparing CDUS with grey-scale transrectal ultrasonography (TRUS) and magnetic resonance imaging (MRI).

PATIENTS AND METHODS

In all, 278 patients who underwent prostate biopsies because of an abnormal digital rectal examination, elevated prostate specific antigen levels, and/or abnormal TRUS between May 1998 and November 1999 were evaluated. The diagnostic accuracies of TRUS, CDUS, MRI and combinations of these imaging techniques in detecting prostate cancer were compared, based on the biopsy results.

RESULTS

Carcinoma was detected in 233 of 1696 specimens, and 87 patients were diagnosed with prostate cancer. For each detected cancer site, the sensitivity of CDUS was lower than those of other imaging techniques, but CDUS had high a specificity and positive predictive value. The combination of grey-scale TRUS and CDUS or MRI improved the sensitivity and negative predictive value. The specificity and positive predictive value of the combination of grey-scale TRUS and MRI were less than those for grey-scale TRUS alone, while those for the combination of grey-scale TRUS and CDUS were higher than those for grey-scale TRUS alone. Five tumours were isoechoic but seen as hypervascular lesions with CDUS.

CONCLUSION

CDUS provides information useful for detecting prostate cancer when used in combination with grey-scale TRUS, and should be included in the routine examination for prostate cancer.

Helical CT of prostate cancer: early clinical experience

OBJECTIVE

[corrected] This study was undertaken to determine whether helical CT can reveal carcinoma of the prostate detected at transrectal sonographically guided biopsy.

MATERIALS AND METHODS

Helical CT of the prostate was performed in 35 patients: 25 with proven prostate cancer (group I) and 10 without cancer detected at biopsy (group II). All patients in group I had cancer in the peripheral zone, and three of these showed foci of cancer in the transitional zone. All patients of group II had undergone at least two sets of biopsy before CT. In group I, areas of contrast enhancement in the peripheral zone of the prostate were defined as suggestive of cancer and correlated with the histopathologic findings.

RESULTS

Helical CT revealed cancer in 22 (88%) of 25 patients with proven prostate cancer. Transrectal sonographically guided biopsy detected 102 cancer sites in the peripheral zone and three in the transitional zone in these 25 patients. Helical CT accurately revealed 59 peripheral zone cancer sites (58%) but did not reveal 43 cancer sites (42%). Abnormal contrast enhancement in the peripheral zone that was not caused by cancer was seen in 10% of suspicious lesions. The three cancer sites in the transitional zone were indistinguishable from benign nodular changes.

CONCLUSION

Prostate cancer detected at transrectal sonographically guided biopsy appears on helical CT of the prostate as focal or diffuse areas of contrast enhancement in the peripheral zone. A prospective study has been initiated to determine the accuracy, sensitivity, and specificity.

Transrectal power Doppler imaging in the detection of prostate cancer

OBJECTIVES

To evaluate the clinical utility of transrectal power Doppler imaging (PDI) of the prostate for detecting prostate cancer in patients with abnormally high serum levels of prostate specific antigen (PSA).

PATIENTS AND METHODS

Patients (107) with abnormally high serum PSA levels were assessed using a digital rectal examination (DRE), transrectal ultrasonography (TRUS) and PDI. Any hypervascular lesion on PDI was graded on a scale of 0-3, where grade 1-3 was considered positive and grade 0 negative. Patients were then diagnosed by prostatic needle biopsy and the results compared with the other detection methods.

RESULTS

Needle biopsy confirmed prostate cancer in 41 (24%) of the 170 patients. PDI was positive in 68, of whom 40 (59%) had prostate cancer; all those but one having prostate cancer were positive on PDI. Thus, PDI had a high sensitivity of 98% (40/41) and a negative predictive value of 99% (101/102). PDI could have saved a significant number of patients from undergoing unnecessary biopsies, compared with DRE and TRUS (P < 0.001).

CONCLUSION

The use of PDI in detecting prostate cancer might reduce the number of unnecessary needle biopsies of the prostate in patients with abnormally high serum PSA levels.

Using gray-scale and color and power Doppler sonography to detect prostatic cancer

OBJECTIVE

We performed a prospective study to assess gray-scale and color and power Doppler sonography for the detection of prostatic cancer and to determine the impact of operator experience.

SUBJECTS AND METHODS

Four radiologists with prior experience using gray-scale and Doppler imaging and four urologists with prior experience limited to gray-scale imaging performed sextant biopsies on 251 patients. Each biopsy site was prospectively scored for gray-scale and Doppler abnormality.

RESULTS

Cancer was detected in 211 biopsy sites from 85 patients. Overall agreement between sonographic findings and biopsy results as measured with the kappa statistic was minimally superior to chance (kappa = 0.12 for gray-scale, kappa = 0.11 for color Doppler, kappa < or =0.09 for power Doppler). With respect to gray-scale diagnosis of cancer, the performance of radiologists (kappa = 0.12) and urologists (kappa = 0.13) was similar. With respect to power Doppler, the performance of radiologists (kappa = 0.09) was superior to that of urologists (kappa = -0.03, p<0.002). Among patients with at least one positive biopsy for cancer, foci of increased power Doppler flow detected by a radiologist were 4.7 times more likely to contain cancer than adjacent tissues without flow.

CONCLUSION

Gray-scale and Doppler imaging did not reveal prostatic cancer with sufficient accuracy to avoid sextant biopsy. Power Doppler may be useful for targeted biopsies when the number of biopsy passes must be limited. There is benefit from increased operator experience with Doppler imaging, but there is no demonstrable benefit of power Doppler over conventional color Doppler sonography.

Imaging prostate cancer

In the detection of prostate cancer, the most important role of imaging is ultrasound-guided prostatic biopsy. In the staging evaluation of prostate cancer, each presently used modality--transrectal US (TRUS), MR imaging, CT, nuclear medicine, and positron emission tomography--has advantages and disadvantages. Evidence-based guidelines on the use of CT and nuclear medicine bone scan, in assessing the risk of distant spread of prostate cancer, are available. There is no consensus and there are no guidelines, however, for the use of imaging in the evaluation of prostate cancer local tumor extent. Results on the value of TRUS vary widely, and prospective multicenter studies suggest that TRUS is no better than digital rectal examination in predicting extracapsular extension. MR imaging offers the most promise for local staging of prostate cancer, but it must resolve problems of reproducible image quality and interobserver variability, and it should prove its efficacy in multicenter trials before it can be recommended for general clinical use. The introduction of MR spectroscopic imaging further expands the value of MR imaging, offering anatomic and metabolic evaluation of prostate cancer.

Contrast-enhanced three-dimensional power Doppler angiography of the human prostate: correlation with biopsy outcome

OBJECTIVES

To determine the feasibility of contrast-enhanced three-dimensional (3D) imaging of the prostatic vasculature using power Doppler imaging and to analyze whether semiquantitative judgments of 3D images with respect to symmetry and distribution of vascular structures correlated with biopsy outcome.

METHODS

3D power Doppler images were obtained before and after intravenous administration of 2.5 g Levovist. Subsequently, random and/or directed transrectal ultrasound (TRUS)-guided biopsies were performed. Vascular images were analyzed by two experts. Prostate vasculature was judged with respect to symmetry and vessel distribution using a (scale) grading system.

RESULTS

Eighteen patients with a suspicion of prostate cancer either because of an elevated prostate-specific antigen (greater than 4.0 ng/mL; Tandem-R-assay) or an abnormal digital rectal examination were included in the study. Prostate cancer was detected in 13 patients. Vascular anatomy was judged abnormal in unenhanced images in 6 cases, of which 5 proved malignant. Enhanced images were considered suspicious for malignancy in 12 cases, including 1 benign and 11 malignant biopsy results. Sensitivity of enhanced images was 85% (specificity 80%) compared with 38% for unenhanced images (specificity 80%) and 77% for conventional gray-scale TRUS (specificity 60%). Of 6 patients who showed no B-mode abnormalities, vascular patterns were judged abnormal in 4 cases, of which 3 were malignant.

CONCLUSIONS

Contrast-enhanced 3D power Doppler angiography is feasible in patients with suspicion of prostate cancer who are scheduled for prostate biopsies. The sensitivity of power Doppler 3D imaging for the detection of prostate malignancy increased from 38% (5 of 13) to 85% (11 of 13) after administration of intravascular microbubble contrast (Levovist), and specificity was found to be 80% (4 of 5) for both imaging modalities. Thus, the use of Levovist when combined with the power Doppler display mode and 3D image reconstruction offers a promising new research area that might prove useful in prostate cancer detection in the future.