Equipment control in a sterile environment using the Gyromouse and a new interface, the user interface (UI) wand.

Providing the surgeon/interventionist with controlling devices that avoid the need for interference of an assistant could enable more direct control and reduce errors due to miscommunication or misinterpretation. Therefore the need for an input device controlling equipment from the sterile environment is high. We evaluated the usability of two hand-held interfaces; an acceleration-sensitive Gyromouse and the User Interface Wand (UI Wand), a new prototype pointing device. The evaluation consisted of a quantitative evaluation in a laboratory setting and a qualitative evaluation using a simulated clinical setting. A quantitative tapping task was performed on a computer screen using target objects of different sizes and positioned at different distances, resulting in a set of indices of difficulties (ID's) based on Fitts' Law. The qualitative task was performed in the simulated clinical setting where images and patient data were viewed and manipulated, and a printer and two loudspeakers controlled. In the quantitative evaluation, the Gyromouse showed to be 25+/-3% (mean+/-SD, n = 11, p<0.05) faster during the tapping task than the UI Wand for ID's>2.5 bits and equally fast for ID's <2.5 bits. In the qualitative evaluation 10 of 11 subjects preferred the UI Wand over the Gyromouse and the UI Wand was considered to enable the quickest control. Both input devices are able to control equipment from the sterile environment. With the Gyromouse, the cursor often has to be searched for after activating, because the cursor remains where it is left and shifts because of drift. Despite being slower and the need for large targets, the UI Wand is preferred due to the absolute pointing characteristic; the cursor is where you are pointing at and, therefore, it is always clear where the cursor is.

New developments in ultrasonography for the detection of prostate cancer.

The introduction of contrast agents has changed the diagnostic role of ultrasonography dramatically. Advanced ultrasound techniques, although currently largely unexplored, especially for prostate applications, were introduced to improve, for example, differential diagnosis. Also, new technologies became available using the interaction of the angioemboli with the transmitted ultrasound waves, and sensitive methods to detect microbubbles were developed. As the traveling of microbubbles through the vascular system is a dynamic process, new information becomes available: when the concentration of the contrast agent can be determined as a function of time, a measure for the actual blood flow can be obtained that provides quantitative information. Initially developed to enhance the ultrasound examinations in cardiac applications, contrast agents can currently be found in radiologic applications as well. The first reports of enhanced Doppler examinations of prostatic blood flow have been published, and the results indicate that contrast agents are a promising addition to the conventional ultrasound examination. In this paper, we present a short overview of the status of transrectal ultrasound imaging in prostate cancer, background information on contrast agents and imaging modalities, and early results of enhanced Doppler studies of the prostate to identify cancer. The early results suggest the feasibility of using angioemboli to enhance ultrasound imaging of prostate diseases, and although many issues remain to be solved, angioemboli in combination with a dedicated imaging modality have the potential to improve the diagnostic application of ultrasound in evaluating the prostate for disease.

Intra-prostatic vasculature studies: can they predict the outcome of transurethral microwave thermotherapy for the management of bladder outflow obstruction?

BACKGROUND: Blood perfusion regulates intraprostatic temperatures during transurethral microwave thermotherapy (TUMT). We evaluated baseline intraprostatic vasculature, as a predictor of efficacy of TUMT. METHODS: Twenty-two patients, with lower urinary tract symptoms (LUTS) suggestive of bladder outflow obstruction, were treated with TUMT (Prostatron). At baseline, three-dimensional contrast-enhanced power-flow-Doppler prostate ultrasonography (3D-CE-PFD) was performed. Assuming that the percentage of perfused area (PPA) is a realistic measure of blood flow, it was used to quantify intraprostatic vasculature. RESULTS: The median (range) age, prostate size, and energy delivered were 66 years (48-80), 47 cm(3) (30-121), 110 kJ (29-136), respectively. The response was 77% (5 failures). The median (range) PPA was 2.76% (0.7-11.3). No difference in PPA among good and poor responders was detected nor was any correlation between PPA and baseline parameters. CONCLUSIONS: The baseline intraprostatic vascularization, documented by CE-PFD studies, has no predictive value for the efficacy of TUMT. It seems that "static" baseline blood flow does not reflect the "dynamic" thermoregulatory role of blood flow during treatment.

Correlation of transrectal ultrasound, computer analysis of transrectal ultrasound and histopathology of radical prostatectomy specimen.

A system for computerised analysis of ultrasonographic prostate images (AUDEX=Automated Urologic Diagnostic EXpert system) for the detection of prostate carcinoma was developed. The ultimate goal is to develop a system that is reliable and non-observer dependent. Results of an earlier study with a small group were encouraging and this study describes the results of the computerised analysis in a larger group. Sixty-two patients who were scheduled to undergo a radical prostatectomy were prospectively analysed. The radical prostatectomy specimens were step-sectioned in the transverse plane, corresponding to the ultrasound pictures. Malignant regions identified by each study were quantified and compared by computer calculation. No correlation was observed between ultrasound analysis and pathology result. For the AUDEX analysis an overall sensitivity of 85% and a specificity of 18% with only a diagnostic accuracy of 57% was noticed when presence or absence of malignancy was evaluated by octant (total 496). When applying a cut-off value of 0.5 ml the numbers were 71%, 33% and 55%, respectively. Correlation was significantly better for the ventral octants. In this study the earlier results of our AUDEX system could not be confirmed. Although sensitivity was good, specificity and especially diagnostic accuracy were lower than expected. We have to conclude that the current settings are inappropriate for routine clinical use. Prostate Cancer and Prostatic Diseases (2001) 4, 56-62

Predictors of treatment outcome for high-energy transurethral microwave thermotherapy.

BACKGROUND AND PURPOSE: Transurethral microwave thermotherapy (TUMT) is an innovative alternative to transurethral resection of the prostate (TURP) for the treatment of lower urinary tract symptoms (LUTS) suggestive of bladder outflow obstruction (BOO). Although the results are satisfactory for the majority of the patients, a considerable number of patients have an unfavorable outcome. Thus, the identification of features able to predict efficacy of TUMT for individual candidates is an important issue. MATERIALS AND METHODS: The available literature in MEDLINE covering the predictive role of various baseline measures for the outcome of high-energy TUMT was reviewed. Direct comparison among various studies was not possible because of differences in thermotherapy devices, treatment protocols, and the definition of a good response to treatment. RESULTS: Predictive features have been detected only for the Prostatron device. A small prostate volume, a low grade of BOO, and advanced age were independent predictors of poor outcome. The strongest predictive feature was the amount of energy delivered during treatment. Histologic characteristics (epithelial:stromal ratio and microvessel density) have not proved predictive for therapeutic outcome. The role of intraprostatic vascularization, as a regulator of the temperature during treatment, seems to be of the greatest importance, but results have not been presented yet. CONCLUSION: The value of baseline clinical measures for the selection of the best candidates for TUMT is limited at best. Variations in the internal structure of the individual prostate seem to play the most important role in regulating the amount of energy absorbed during treatment, and further research must focus on this item.

Three-dimensional contrast-enhanced power Doppler ultrasonography and conventional examination methods: the value of diagnostic predictors of prostate cancer.

OBJECTIVE: To investigate the value of three-dimensional contrast-enhanced power Doppler ultrasonography (3D-CE-PDU) in the diagnosis of prostate cancer and to compare 3D-CE-PDU with digital rectal examination (DRE), prostate-specific antigen (PSA) levels, grey-scale ultrasonography (GSU) and PDU. PATIENTS AND METHODS: The study comprised 30 patients with localized prostate cancer scheduled to undergo radical prostatectomy and 29 with clinical BPH scheduled to undergo transurethral microwave thermotherapy. The 3D-CE-PDU examinations were carried out using 2.5 g of microbubble ultrasound contrast medium; the images were stored digitally to allow off-line analysis. All the reconstructed 3D images of the prostate were evaluated blindly in random order by two investigators (one expert and one novice). The images were scored according to asymmetry (0-2) and vessel distribution (0-3). Marked asymmetry (2) and/or a focal increase in vascularity (> 2) were considered as suspicious for prostate malignancy. Diagnostic predictions using the DRE, PSA level, GSU, PDU, 3D-CE-PDU and their combinations were investigated using receiver operating characteristic (ROC) curves. RESULTS: True-positive and true-negative rates of the 3D-CE-PDU were 87% (26/30) and 79% (23/29), respectively, for the expert observer. The sensitivity of 3D-CE-PDU was higher than that of DRE, GSU and PDU, but not PSA level, and the specificity was lower, again except for PSA level. However, when compared with those of the other modalities in single-test evaluations, 3D-CE-PDU, and a combination of 3D-CE-PDU and PSA level, had the largest area under the ROC curve (0. 830 and 0.933, respectively). The diagnostic agreement between the examiners was 76% (Cohen kappa statistic, 0.5). CONCLUSION: In this selected group of patients, 3D-CE-PDU alone was a better diagnostic tool than the DRE, PSA level, GSU or PDU alone. The most suitable diagnostic predictor for prostate cancer was a combination of 3D-CE-PDU and PSA level.

The application of three-dimensional contrast-enhanced ultrasound to measure volume of affected tissue after HIFU treatment for localized prostate cancer.

INTRODUCTION: Adequate monitoring of volume and location of affected tissue might provide helpful information when performing localized ablative therapy for prostate cancer. We hypothesize that the change in blood flow patterns after therapy in comparison to the blood flow pattern prior to therapy can be used to locate and quantify the amount of affected tissue due to the therapy. We describe the use of three-dimensional contrast-enhanced power Doppler ultrasound (3D-CE-PDU) to determine its additive value to visualize the extent of tissue defects created by high-intensity focused ultrasound (HIFU) in correlation with the histopathology of the prostatectomy specimen. MATERIALS AND METHODS: Nine patients with biopsy-proven localized prostate cancer, who gave informed consent, were included in the protocol. HIFU treatment was performed 1 week in advance of radical retropubic prostatectomy (RRP) as part of a protocol to study the value of HIFU treatment as local ablative therapy for clinical T(1-2)N(0)M(0) prostate carcinoma. 3D-CE-PDU was performed 1 day prior to unilateral HIFU treatment of the affected lobe on biopsy indication and 1 day before RRP using 2.5 g Levovist((R)) (Schering AG, Germany) microbubble ultrasound contrast agent and a Kretz((R)) Voluson 530D ultrasound scanner (Kretztechnik AG, Austria). Ultrasound data and pathology whole-mount sections were stored digitally to allow off-line processing. Human interpretations of HIFU measurements in three-dimensional ultrasound data were based on gray-scale information (local increase in gray level) in combination with power Doppler mode (absence of blood flow). Histopathological analysis of the whole-mount section revealed a broad band of hemorrhagic necrosis in the HIFU-treated area. Using both the ultrasound data and the pathology sections, the total volume of the prostate and of the HIFU-treated area was measured, and relative volumes were obtained. RESULTS: Visual inspection of the three-dimensional reconstruction of contrast-enhanced Doppler measurements revealed the HIFU-affected prostate tissue by the absence of a blood flow pattern. Paired t tests of the relative HIFU volume indicated that Doppler results (mean 21.7%, SD +/-10.8%) differed from the pathology results (mean 32.6%, SD +/-16.0%), but a good correlation was found between the relative pathology HIFU volume (Pearson correlation r = 0.94, p<0.0015) and mean 3D-CE-PDU HIFU. Closer inspection of the pathology specimen revealed that the outer ring of the macroscopic hemorrhagic necrosis overestimated the actually dead tissue. On microscopy, the border of dead tissue appeared to be 1-2 mm inside the macroscopically identified red hemorrhagic band. 3D-CE-PDU HIFU volumes indicated by the single observers were not statistically different and correlated very well (Pearson correlation r = 0.98, p<0.001). CONCLUSION: The results illustrate that 3D-CE-PDU is a promising method to determine the size of the defect of HIFU ablative therapy for prostate carcinoma. The absence of blood flow indicated by three-dimensional power Doppler ultrasound images reflects affected tissue after HIFU treatment, and volume measurements of these areas can quantify the amount of affected tissue.

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.

Contrast angiosonography: a technology to improve Doppler ultrasound examinations of the prostate.

OBJECTIVES: A feasibility study to evaluate whether analysis techniques adapted from X-ray angiography can be used to analyze the transient enhancement of prostate blood flow patterns in color Doppler maps as obtained after administering ultrasound contrast agents. METHODS: Injections of ultrasound contrast agents were given to dogs and humans, and color Doppler blood flow patterns in fixed transverse sections through the prostate were recorded on video tape. Computer assistance of Doppler signals over time is used to evaluate the transient enhancement of flow patterns obtained with contrast-enhanced Doppler ultrasound. Results are compared to indicator dilution curve theory as used in, e.g., X-ray angiography. RESULTS: Administering a contrast agent to improve color Doppler evaluation of prostate blood flow resulted in clear enhancement of Doppler signal intensities without unwanted side effects. Using the computer, the perfused area of the prostate could be obtained quantitatively over time showing profiles of individual heartbeats. Averaging the perfused area over one heartbeat resulted in an indicator dilution curve, and correlation with dilution theory indicated the feasibility of applying wash-in and wash-out analysis of contrast agents in color Doppler images. CONCLUSION: Frame-by-frame interpretation by the computer indicated the feasibility of analyzing the transient enhancement of blood flow visibility in the Doppler image over time using techniques such as wash-in and wash-out time. This technology provides researchers in the field of ultrasound evaluation of the prostate the opportunity to apply a new diagnostic tool, contrast angiosonography, in their research. This method for analysis of prostatic blood flow can be helpful in any application that affects the blood supply of the prostate such as heat treatments and hormonal treatments.

Feasibility of minimally invasive intrauterine fetal access in a monkey model.

PURPOSE: We evaluated new intervention techniques and surgical instruments in a fetal monkey model to determine improvements that would be useful for early intrauterine intervention. Our findings may be helpful in the future for treating select cases of severe prenatal obstructive uropathology. MATERIALS AND METHODS: In a series of experiments on 18 pregnant rhesus monkeys (Macaca mulatta) at mid trimester we assessed various endoscopic intra-amniotic access techniques as well as morbidity, mortality and possibilities for fetoscopy. RESULTS: In all 18 fetuses adequate fetoscopy was possible with no maternal mortality. Of the 18 pregnancies 14 went to term with no early or late postoperative complications. Technical improvements changed the intrauterine access technique from open placement of trocars to the use of the Seldinger technique, gun introduction of needles with small caliber sheets and small caliber introduction trocars, resulting in minimal amniotic membrane separation. Various rigid and flexible endoscopes were evaluated for fetoscopy and up to 3 cannulas were placed. No change in the fetal growth pattern was observed on postoperative ultrasound. Subsequent pregnancies occurred during this study period, and there were no acceptance problems of the newborns by the mothers. CONCLUSIONS: New techniques have led to improved intrauterine fetal access. Morbidity mainly depends on the disruption of amniotic membranes, which has an important preterm role. Adapted endoscopes and other instruments offer new possibilities for fetal diagnosis and therapy in the future. Our primate model seems to be suitable for evaluating these new techniques before they are used in a clinical setting.

Aspects of imaging in the assessment and follow up of benign prostatic hyperplasia.

For assessing patients suffering from benign prostatic hyperplasia and monitoring subsequent treatment, symptom questionnaires, uroflowmetry, prostate volume measurements, postvoiding residual urine volume measurements and pressure-flow studies may be used. This review highlights aspects of imaging in the assessment of benign prostatic hyperplasia, including volume determinations of prostate and postvoiding residual urine, texture imaging and biopsy guidance. Future developments are also briefly discussed.

Transrectal ultrasound imaging of the prostate: review and perspectives of recent developments.

We present a critical review of the recent literature and discuss the development and prospective view of the evaluations of transrectal ultrasound with regard to prostate malignancy. We illustrate this with personal experiences. Material and Methods: Based on a critical evaluation of clinical data we address the apparent shortcoming of greyscale transrectal ultrasonography in the assessment of prostate cancer. New developments and future possibilities are also discussed. Evaluation of the value of greyscale transrectal ultrasonography in the diagnosis of prostate cancer indicates a limited role, because of the non-uniform appearance of prostate cancer on the ultrasound images. Ameliorating of transrectal ultrasound, like the use of contrast ultrasonography, could improve the detection of prostate cancer. Although the use of greyscale transrectal ultrasonography lacks sensitivity and specificity for the diagnosis of prostate cancer, its use in volume measurement of the prostate and biopsy guidance is unquestionable. The first results of the application of contrast ultrasonography are promising, both in detection of prostate cancer as in treatment follow up. Other developments like improvement of transducer and computer technology could make the use of ultrasound more versatile. However, future research will indicate whether all these improvements will lead to clinical applications.

Edge detection in prostatic ultrasound images using integrated edge maps.

OBJECTIVE: We investigated an algorithm to detect grey level transitions with multiple scales of resolution to improve edge detection and localisation in ultrasound images of the prostate. INTRODUCTION: We had developed a non-analytical operator for prostate contour determination implemented with minimum and maximum filters and locate edges. We implemented a technique for improved determination of boundary parts in prostatic ultrasound images by adjusting the edge detection parameter to signal information. METHODS: First the influence of prefilter settings and edge detection parameters is investigated in a test image and a real ultrasound image. Then, local standard deviation is used to identify or fewer homogeneous regions that are filtered with course resolution, while areas with larger deviation that grey level transitions occur, which should be preserved using smaller filter sizes to improve edge localisation. RESULTS: Analysis of images with different filter sizes indicated that areas are merged for increasing filter sizes: less pronounced edges disappear or displace for larger filters. Two scales of resolution lead to an improved localisation of edges when smaller filter sizes are used in areas with an increased local standard deviation. CONCLUSIONS: This paper illustrates an edge detection method suitable as pre-processing step in interpretation of medical images. By adapting input parameters to signal information, object recognition can be applied in images from different imaging modalities. Also, disadvantages are discussed, resulting in a new application combining a localisation algorithm to find the initial contour and a delineation algorithm to improve the outlining of the resulting contour.

Transrectal ultrasound of the prostate: innovations and future applications.

PURPOSE: We present a critical evaluation of the use of ultrasound for prostate disease examination in urological practice, and provide perspectives on ultrasound applications that may become important for the future evaluation of prostate problems. MATERIALS AND METHODS: Based on an evaluation of clinical data in cases suspicious for prostatic malignancy, we addressed the apparent shortcomings of transrectal ultrasound for accurately diagnosing prostate cancer. Future applications presented in the literature were noted. RESULTS: Evaluating the ultrasound data in cases suspicious for malignancy indicated that imaging has little advantage over digital rectal examination for detecting malignant areas. The new applications of ultrasound that hold great promise for use in the urology clinic include the injection of contrast agents to obtain information on blood supply, temperature estimation for the noninvasive assessment of temperature distributions during heat treatment and a therapeutic application for local treatment of prostate cancer. CONCLUSIONS: While differential diagnosis with ultrasound appears to result in disappointing sensitivity and specificity values, its use in volume measurement and biopsy guidance is unquestioned. The development of new applications may improve the clinical value of ultrasound in urological practice. The application of ultrasound contrast agents for the detection and clinical staging of prostate cancer is especially promising. Future research will indicate whether the promise evolves in clinical applications.

The correlation between prostate volume, transition zone volume, transition zone index and clinical and urodynamic investigations in patients with lower urinary tract symptoms.

OBJECTIVE: To determine if, in patients with lower urinary tract symptoms (LUTS), measurement of the transition zone (TZ) of the prostate by transrectal ultrasonography (TRUS) and the ratio between the TZ volume and total prostate volume (TZ index) correlates better with clinical and urodynamic investigations than total prostate volume alone. PATIENTS AND METHODS: In total, 150 consecutive patients with LUTS underwent a standardized screening programme including the International Prostate Symptom Sore (IPSS), a physical examination, TRUS of the prostate and urodynamic investigations with pressure-flow studies. The total prostate volume and TZ volume were assessed from TRUS using the ellipsoid formula. Spearman's rank correlation coefficients were calculated between different prostate volume measurements and specific symptomatic and urodynamic variables. RESULTS: The relationships between specific IPSS symptoms, symptom scores and the prostate volume measurements were not statistically significant except for one domain, nocturia, that appeared to be statistically significantly correlated with the TZ index (r = 0.25). The correlations for free flow, pressure-flow variables and prostate volume measurements were stronger, but only moderate at best. The highest correlations were between TZ volume and the linear passive urethral resistance obstruction category, urethral resistance factor and detrusor pressure at maximum flow (r = 0.43, 0.44 and 0.40, respectively). The differences between the correlations of prostate volume and TZ index and these variables were small (r = 0.39, 0.38 and 0.37, respectively for prostate volume and r = 0.38, 0.40 and 0.33 respectively for TZ index). CONCLUSIONS: There were very small differences between the correlations of total prostate volume, TZ volume and TZ index, and clinical and pressure-flow variables. In the assessment of the last two, the estimation of the total prostate volume by TRUS was a reasonable way to obtain the required information about prostate size and measuring TZ volume and calculating TZ index was of limited additional value. Symptoms and bladder outlet obstruction were mainly determined by other factors than the prostate and, specifically, TZ volume. As earlier studies have indicated that including pressure-flow data in the pre-operative evaluation and selection of patients for interventional therapies may improve the overall clinical results, we think that prostate volume, TZ volume or symptoms alone should not be used as the main indication for deciding on the appropriate invasive treatment options.

[Diagnosis of prostate cancer in urination disorders in urological practice: current status and future developments]. / Diagnostiek van prostaatkanker bij mictieklachten in de urologische praktijk: huidige stand van zaken en toekomstige ontwikkelingen.

This paper presents the current diagnostics of patients with prostate related problems (lower urinary tract symptoms) who visit the urology clinic. The diagnostic triad for prostate cancer detection is presented, consisting of a serum Prostate-Specific Antigen test, a digital rectal examination to palpate the prostate, and transrectal ultrasound of the prostate to visualise internal structures and guide the urologist in taking biopsies. The results of the tests for a biopsied population of 232 patients illustrate the shortcomings of the individual tests in predicting the presence of a malignancy. Biopsies are needed to prove or rule out prostate cancer in case of a suspicion. Future developments in early detection of prostate cancer are directed to improve the clinical use of the current diagnostic triad, and to identify new diagnostic tools.

Standardized assessment to enhance the diagnostic value of prostate volume; Part I: Morphometry in patients with lower urinary tract symptoms.

BACKGROUND: The diagnostic value of prostate volume results has been evaluated in patients with prostate problems of benign cause. METHODS: For 247 patients, automated volume results were compared to manual results of planimetric reference volume and of the classical ellipsoid formula. Also, transition zone volume was estimated and growth curves of the prostate and prostate dimensions over age were investigated. RESULTS: Application of automated volume determination gives accurate results compared to the reference volume (Pearson correlation, R = 0.938). The ellipsoid volume results were slightly less correlated (R = 0.921). Average growth of the entire prostate was 1.7% per year, for the transition zone the growth was 4.3%. Compared to growth rates for a community-based population, comparable growth rates were found for our group that had higher mean prostate volume. CONCLUSIONS: The results indicate that the age of onset of volume growth is the determining factor in developing benign prostate enlargement not a change in growth rate.

Standardized assessment to enhance the diagnostic value of prostate volume; Part II: Correlation with prostate-specific antigen levels.

BACKGROUND: Standardized estimations of prostate volumes are used for interpretation of prostate specific antigen (PSA) levels. METHODS: In 243 patients with clinically benign diagnosis, automated and reference prostate volumes and transition zone volumes are correlated to PSA levels. Besides, growth curves of PSA level when aging are determined. RESULTS: The strongest correlation was found with multiple regression analysis between PSA and transition zone volume and rest volume (R = 0.854). Mean PSA density was 0.092 ng/mL2, its labelling quality for benign disease was 91% (threshold = 0.15 ng/mL2). An average growth factor for PSA levels of 2.9% per year was obtained. CONCLUSIONS: The contribution per unit tissue to PSA level was for the transition zone 1.9 times higher than for the rest volume. Average growth of PSA per year is in consonance with the increase in normal levels of age specific PSA ranges, although only weak correlations were found between PSA and age and PSA density and age.

Reproducibility of prostate volume measurements from transrectal ultrasonography by an automated and a manual technique.

OBJECTIVE: To assess the reproducibility of estimates of prostate volume determined by planimetry from transrectal ultrasonography (TRUS) images. MATERIALS AND METHODS: Two sequential sessions of images obtained by TRUS were obtained from 30 patients, with the ultrasound probe removed and inserted between the sessions. The stored images were outlined, both manually and by computer, and measurements of prostate volume obtained planimetrically. In addition, the ability of the urologist to accurately draw the contour was assessed by outlining predefined contours. RESULTS: The mean (SD) variability of manual outlining between sessions was 3.5 (3.4)%, within one session was 1.7 (1.3)% and of computer outlining between sessions was 4.3 (3.8%). Comparing the results of manual and computer outlining showed a mean (SD) variability of 7.5 (5.6)%, with larger values obtained from computer outlining. The mean (SD) variation in manually outlining predefined contours was 1.4 (1.4)%. CONCLUSIONS: The variability of computer outlining was slightly higher than expected theoretically. The within-session variability was higher than the variation caused by errors in outlining predefined contours, indicating that the interpretation of TRUS images differed with time. Automated determination of prostate volume can save time during clinical investigation and the variability is within the clinically acceptable range of 5%.