Functional MRI evaluation of blood oxygen dependent (BOLD) in renal allograft dysfunction: a prospective study.

BACKGROUND: Blood oxygen level dependent-magnetic resonance imaging (BOLD-MRI) is a non-invasive functional imaging technique that can be used to assess renal allograft dysfunction. PURPOSE: To evaluate the diagnostic performance of BOLD-MRI using a 3-T scanner in discriminating causes of renal allograft dysfunction in the post-transplant period. MATERIAL AND METHODS: This prospective study was conducted on 112 live donor-renal allograft recipients: 53 with normal graft function, as controls; 18 with biopsy-proven acute rejection (AR); and 41 with biopsy-proven acute tubular necrosis (ATN). Multiple fast-field echo sequences were performed to obtain T2*-weighted images. Cortical R2* (CR2*) level, medullary R2* (MR2*) level, and medullary over cortical R2* ratio (MCR) were measured in all participants. RESULTS: The mean MR2* level was significantly lower in the AR group (20.8 ± 2.8/s) compared to the normal group (24 ± 2.4/s, P <0.001) and ATN group (27.4 ± 1.7/s, P <0.001). The MCR was higher in ATN group (1.47 ± 0.18) compared to the AR group (1.18 ± 0.17) and normal functioning group (1.34 ± 0.2). Both MR2* (area under the curve [AUC] = 0.837, P <0.001) and MCR (AUC = 0.727, P = 0.003) can accurately discriminate ATN from AR, however CR2* (AUC = 0.590, P = 0.237) showed no significant difference between both groups. CONCLUSION: In early post-transplant renal dysfunction, BOLD-MRI is a valuable non-invasive diagnostic technique that can differentiate between AR and ATN by measuring changes in intra-renal tissue oxygenation.

Renal arterial embolization: Indications, angiographic findings, and outcomes in a series of 170 patients.

Background: The lack of overall experience and reporting on angiographic findings in previously published studies of renal arterial embolization (RAE) compelled us to report our overall experience on a series of patients. Materials and methods: A retrospective study was performed analyzing data of patients enrolled for RAE between 2010 and 2019. History, physical examination, and laboratory data were reviewed for all patients. Abdominal ultrasound was the initial imaging study, and all patients underwent subsequent computed tomography or magnetic resonance imaging. The outcome of RAE was determined based on radiographic and clinical findings. Results: Data from 202 patients were analyzed, with a mean age of 45 ± 15 years, and 71.3% of patients were male. Iatrogenic injury was the most common indication for RAE (54%), followed by renal tumors, trauma, and spontaneous, in 27.7%, 10.4%, and 8.4% of patients, respectively. Renal angiography revealing pseudoaneurysm alone or with other pathology in the lower pole of the kidney was the most common finding (40.6%), whereas no lesions were identified on angiography in 32 patients (15.8%), after which RAE was subsequently aborted. Renal arterial embolization was successful in 158 of 170 patients (92.9%) after 1 or more trials (maximum of 4). Microcoil alone or with other embolic materials was the most commonly used material for embolization (85%). Conclusions: Iatrogenic injury was the most common indication for RAE. Pseudoaneurysm alone or with other lesions was the most common lesion on renal angiography; however, angiography showed a negative result in 16% of patients, even those with symptoms. When lesions are present on angiography, the overall success of repeated trials of RAE reached 92.9%.

Predictors of renal angioembolization outcome: A retrospective analysis with 148 patients at a tertiary urology institute.

Objective: The aim of this study was to evaluate the predictor of unsuccessful outcome of renal angioembolization (RAE). Knowing those predictors may help in avoiding unnecessary RAE procedures and their associated side effects, while helping to prepare for an alternate procedure and improving patient's overall satisfaction. Methods: A retrospective analysis between January 2006 and December 2018 was performed, and the indications for RAE were classified into post-traumatic, iatrogenic, renal tumors, and spontaneous. Patients who underwent RAE prior to nephrectomy were eliminated. Computed tomography angiography was performed in patients with normal renal function and those who had no contrast allergy, otherwise magnetic resonance angiography was performed. For the purpose of statistical analysis, we stratified patients into two main categories based on the final outcome-successful or failed. Results: Of 180 patients, 32 with negative angiography were eliminated, leaving 148 patients; 136 (91%) had successful outcomes after one or more trials and 12 had unsuccessful outcomes. The mean age was 45±15 years, and 105 (71%) were male. Neither gender, side of the lesion, presence of hematuria, indication for RAE, nor the type of lesion affected the outcome. On the other hand, renal anatomy with presence of accessory artery was the only predictor to failed RAE (p=0.001). Failed RAE trial was a predictor for nephrectomy as a secondary procedure (p=0.03). Conclusion: No pre-procedural predictors could anticipate the RAE outcome, and different indications can be scheduled to RAE, which is equally effective. The presence of accessory renal artery on diagnostic angiography is the only factor that may predict the failure of the procedure.

Influences of the Social Media Continuum Model in Radiology: Theory and Reality.

Social media utilization has been growing exponentially worldwide and has created a thriving venue for radiologists and the profession of radiology to engage in on both the academic and social levels. The aim of this article is to conduct updated literature review and address a gap in the literature by introducing a simple classification for social media utilization and a new theoretical model to outline the role and potential value of social media in the realm of radiology. We propose classifying social media through usage-driven and access-driven indices. Furthermore, we discuss the interdependency of radiologists, other physicians and non-physician stakeholders, scientific journals, conferences/meetings and the general public in an integrated social media continuum model. With the ongoing sub-specialization of radiology, social media helps mitigate the physical barriers of making connections with peers and audiences which would have otherwise been unfeasible. The constant evolution and diversification of social media platforms necessitates a novel approach to better understand its role through a radiological lens. With the looming fear of 'ancillary service' labelling, social media could be the golden plate to halt the path towards commoditization of radiology.

The accuracy of computed tomography in the diagnosis of upper urinary tract urothelial carcinoma in correlation with the final histopathology: A retrospective study in 275 patients at a Tertiary Urology Institute.

INTRODUCTION: Because the reports in the literature of radiologic investigations for upper tract urothelial cancer (UTUC) are limited by the number of patients, and included patients with different pathologies, we aimed to study the overall accuracy of computed tomography (CT) in the diagnosis of UTUC and their accuracy on predicting tumor location. METHODS: A retrospective review from 1990 to 2017 included patients who were treated for UTUC. Unenhanced CT scan was obtained first using Multi-Detector Computed Tomography (MDCT, Philips Medical Systems), then nonionic contrast medium, containing 350 mg iodine/ml was injected at 4 mL/s. Analysis was performed using SPSS®. RESULTS: Of 275 patients, complete data on CT was available on 270 (98%) patients. CT reported only two false positive and six false negative results and the overall accuracy was 96-97%. In comparison to the final pathological reports, CT/CTU detected 85% of the tumor location of in the renal pelvic and 50% of the calyceal tumors. In ureteric tumors, they detected distal (66/71= 93%) more than proximal ureteric tumors (60%). CONCLUSION: In our cohort, CT/ CTU has a high overall accuracy (97%) in diagnosing UTUC, capability to well visualize tumors of distal ureter and renal pelvis, but could miss calyceal tumors. The matter to rely only on CT without ureteroscopic biopsy in the diagnosis of UTUC especially if radical surgery is planned needs further prospective studies.

Prostate Imaging Reporting and Data System (PI-RADS): What the radiologists need to know?

We aim to review the new modifications in MR imaging technique, image interpretation, lexicon, and scoring system of the last version of Prostate Imaging Reporting and Data System version 2.1 (PI-RADS v2.1) in a simple and practical way. This last version of PI-RADS v2.1 describes the new technical modifications in the protocol of Multiparametric MRI (MpMRI) including T2, diffusion-weighted imaging (DWI), and dynamic contrast enhancement (DCE) parameters. It includes also; new guidelines in the image interpretation specifications in new locations (lesions located in the central zone and anterior fibromuscular stroma), clarification of T2 scoring of lesions of the transition zone, the distinction between DWI score 2 and 3 lesions in the transition zone and peripheral zone, as well as between positive and negative enhancement in DCE. Biparametric MRI (BpMRI) along with simplified PI-RADS is gaining more acceptances in the assessment of clinically significant prostatic cancer.

Imaging of Bladder Cancer: Standard Applications and Future Trends.

The evolution in imaging has had an increasing role in the diagnosis, staging and follow up of bladder cancer. Conventional cystoscopy is crucial in the diagnosis of bladder cancer. However, a cystoscopic procedure cannot always depict carcinoma in situ (CIS) or differentiate benign from malignant tumors prior to biopsy. This review will discuss the standard application, novel imaging modalities and their additive role in patients with bladder cancer. Staging can be performed with CT, but distinguishing between T1 and T2 BCa (bladder cancer) cannot be assessed. MRI can distinguish muscle-invasive from non-muscle-invasive tumors with accurate local staging. Vesical Imaging-Reporting and Data System (VI-RADS) score is a new diagnostic modality used for the prediction of tumor aggressiveness and therapeutic response. Bone scintigraphy is recommended in patients with muscle-invasive BCa with suspected bony metastases. CT shows low sensitivity for nodal staging; however, PET (Positron Emission Tomography)/CT is superior and highly recommended for restaging and determining therapeutic effect. PET/MRI is a new imaging technique in bladder cancer imaging and its role is promising. Texture analysis has shown significant steps in discriminating low-grade from high-grade bladder cancer. Radiomics could be a reliable method for quantitative assessment of the muscle invasion of bladder cancer.

CT and MRI in Urinary Tract Infections: A Spectrum of Different Imaging Findings.

There are many acute and chronic infections affecting the urinary tract including bacterial, fungal and viral infections. Urinary tract infections (UTIs) can present in many different patterns with variable degrees of severity varying from asymptomatic and uncomplicated forms to life threatening complicated infections. Cross-sectional imaging techniques-including both computed tomography (CT) and magnetic resonance imaging (MRI)-have become very important tools not only for evaluation of UTIs, but also for detection of associated complications. Selection of either CT or MRI in the UTI evaluation depends on several factors such as the presence of contraindication, experience, cost and availability. CT and MRI help in early detection and management of UTIs that reduce the prevalence and severity of complications. In this article we will present the radiologic findings at CT and MRI in different types of upper and lower UTIs including acute pyelonephritis, intrarenal and perinephric abscesses, pyonephrosis, chronic pyelonephritis, emphysematous UTIs, xanthogranulomatous pyelonephritis, tuberculosis (TB), bilharziasis, fungal infection, corynebacterium infection, ureteritis, cystitis, prostatitis, prostatic abscess and urethritis.

The role and contribution of treatment and imaging modalities in global cervical cancer management: survival estimates from a simulation-based analysis.

BACKGROUND: Cervical cancer is the fourth most common cancer among women worldwide, causing more than 300 000 deaths globally each year. In addition to screening and prevention, effective cancer treatment is needed to reduce cervical cancer mortality. We discuss the role of imaging in cervical cancer management and estimate the potential survival effect of scaling up imaging in several different contexts. METHODS: Using a previously developed microsimulation model of global cancer survival, we estimated stage-specific cervical cancer 5-year net survival in 200 countries and territories. We evaluated the potential survival effect of scaling up treatment (chemotherapy, surgery, radiotherapy, and targeted therapy), and imaging modalities (ultrasound, x-ray, CT, MRI, PET, and single photon emission CT [SPECT]) to the mean level of high-income countries, both individually and in combination. FINDINGS: We estimate global cervical cancer 5-year net survival as 42·1% (95% uncertainty interval [UI] 33·8-48·5). Among individual imaging modalities, expanding MRI would yield the largest 5-year survival gains globally (data are absolute percentage point increase in survival 0·6, 95% UI 0·1-2·1), scaling up ultrasound would yield the largest gains in low-income countries (0·5, 0·0-3·7), expanding CT and x-ray would have the greatest effect in Latin America (0·8, 0·0-3·4) and Oceania (0·4, 0·0-3·2), and expanding PET would yield the largest gains in high-income countries (0·2, 0·0-0·8). Scaling up SPECT did not show major changes in any region. Among individual treatment modalities, scaling up radiotherapy would yield the largest absolute percentage point gains in low-income countries (5·2, 0·3-13·5), and expanding surgery would have the largest effect in lower-middle-income countries (7·4, 0·3-21·1) and upper-middle-income countries (0·8, 0·0-2·9). Estimated survival gains in high-income countries were very modest. However, the gains from expanding any single treatment or imaging modality individually were small across all income levels and geographical settings. Scaling up all treatment modalities could improve global 5-year net survival to 52·4% (95% UI 44·6-62·0). In addition to expanding treatment, improving quality of care could raise survival to 57·5% (51·2-63·5), and the cumulative effect of scaling up all imaging modalities together with expanded treatment and quality of care could improve 5-year net survival for cervical cancer to 62·5% (57·7-67·8). INTERPRETATION: Comprehensive scale-up of treatment, imaging, and quality of care could substantially improve global cervical cancer 5-year net survival, with quality of care and imaging improvements each contributing about 25% of the total potential gains. These findings suggest that a narrow focus on the availability of treatment modalities could forgo substantial survival gains. Investments in imaging equipment, personnel, and quality of care efforts will also be needed to successfully scale up cervical cancer treatment worldwide. FUNDING: Harvard T H Chan School of Public Health and National Cancer Institute.

68Ga-PSMA-11 PET/CT in newly diagnosed prostate cancer: diagnostic sensitivity and interobserver agreement.

PURPOSE: To determine the diagnostic sensitivity and interobserver agreement of Gallium 68-prostate-specific membrane antigen positron emission tomography/computed tomography (68Ga-PSMA-11 PET/CT) imaging for diagnosis and staging of patients with newly diagnosed prostate cancer (PC). MATERIALS AND METHODS: One hundred and seventy-three men (mean age, 68 ± 7.7 years; range 46-84 years) with newly diagnosed, untreated PC were enrolled in this prospective study between January 2017 and August 2018. All patients underwent a 68Ga-PSMA-11 PET/CT examination. For each patient, we determined the disease stage, the Gleason score, and the maximum standardized uptake value (SUVmax) for primary prostatic tumor and extraprostatic metastases. The diagnostic sensitivity and interobserver agreement of 68Ga-PSMA-11 PET/CT for diagnosis and staging of PC were established by histopathology as the reference standard. RESULTS: 68Ga-PSMA-11 PET/CT examinations were interpreted as positive for PC in 166 of 173 patients (101 patients had primary prostatic tumor only, two patients had extraprostatic metastases only and 63 patients had combined lesions). The sensitivity of 68Ga-PSMA-11 PET/CT examination in the diagnosis of PC was 96%. 68Ga-PSMA-11 PET/CT produced a significant change of stage in 28.6% patients with an upstage in 17.9% patients and a downstage in 10.7% patients. The interobserver agreements were almost good to perfect (k = 0.63-0.89) for visual image interpretation, SUVmax measurement, and tumor staging. CONCLUSION: 68Ga-PSMA-11 PET/CT is a valuable tool with high diagnostic sensitivity (96%) and high reproducibility for diagnosis and staging of patients with newly diagnosed PC.

Statistical analysis of ADCs and clinical biomarkers in detecting acute renal transplant rejection.

OBJECTIVE: The main goal of this study is to determine which parameters [e.g. clinical biomarkers, demographics and image-markers using 4D (3D + b-value) diffusion-weighted MRI (DW-MRI)] are more correlated with transplanted kidney status in patients who have undergone kidney transplantation, and can be used for early assessment of acute renal rejection. METHODS: The study included 16 patients with stable graft function and 37 patients with acute rejection (AR), determined by renal biopsy post-transplantation. 3D DW-MRI of each allograft had been acquired using a series of b-values 50 and 100-1000 in steps of 100 smm-2. The kidney was automatically segmented and co-aligned across series for motion correction using geometric deformable models. Volume-averaged apparent diffusion coefficients (ADCs) at each b-value were calculated. All possible subsets of ADC were used, along with patient age, sex, serum plasma creatinine (SPCr) and creatinine clearance (CrCl), as predictors in 211 logistic regression models where AR was the outcome variable. Predictive value of ADC at each b-value was assessed using its Akaike weight. RESULTS: ANOVA of the saturated model found that odds of AR depended significantly on SPCr, CrCl and ADC at b = 500, 600, 700 and 900 smm-2. The model incorporating ADC at b = 100 and700 smm-2 had the lowest value of the Akaike information criterion; the same two b-values also had the greatest Akaike weights. For comparison, the top 10 submodels and the full model were reported. CONCLUSION: Preliminary findings suggest that ADC provides improved detection of AR than lab values alone. At least two non-zero gradient strengths should be used for optimal results. Advances in knowledge: This paper investigated possible correlations between image-based and clinical biomarkers, and the fusion of both with respect to biopsy diagnosis of AR.

Diagnostic value of combined static-excretory MR Urography in children with hydronephrosis.

The aim of this study was to determine the feasibility, accuracy and diagnostic potential of combined static-excretory MR Urography in children with sonographically detected hydronephrosis. We prospectively evaluated 28 children (11 girls and 17 boys), mean age 8.3 years (range 2 months-16 years). Static-excretory MR Urography was performed in all cases. The results of MR Urography were compared with the results of other imaging modalities, cystoscopy and surgery. In 28 children, 61 renal units were evaluated by MR Urography (the renal unit is the kidney and its draining ureter). The final diagnoses included: normal renal units (n = 23); uretropelvic junction obstruction (n = 14); megaureter (n = 8); midureteric stricture (n = 1), complicated duplicated systems (n = 5), post ESWL non-obstructive dilation (n = 2), extrarenal pelvis (n = 4), dysplastic kidney (n = 4). Complex pathology and more than one disease entity in were found in 7 children. The MRI diagnosis correlated with the final diagnosis in 57 units, with diagnostic accuracy 93.4%. In conclusions static and excretory MRU give both morphological and functional information in a single examination without exposure to ionizing radiation and iodinated contrast agent. It is a valuable imaging technique for children with upper urinary tract dilatation; especially in cases of complex congenital pathologies and severely hydronephrotic kidney.

Models and methods for analyzing DCE-MRI: a review.

PURPOSE: To present a review of most commonly used techniques to analyze dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), discusses their strengths and weaknesses, and outlines recent clinical applications of findings from these approaches. METHODS: DCE-MRI allows for noninvasive quantitative analysis of contrast agent (CA) transient in soft tissues. Thus, it is an important and well-established tool to reveal microvasculature and perfusion in various clinical applications. In the last three decades, a host of nonparametric and parametric models and methods have been developed in order to quantify the CA's perfusion into tissue and estimate perfusion-related parameters (indexes) from signal- or concentration-time curves. These indexes are widely used in various clinical applications for the detection, characterization, and therapy monitoring of different diseases. RESULTS: Promising theoretical findings and experimental results for the reviewed models and techniques in a variety of clinical applications suggest that DCE-MRI is a clinically relevant imaging modality, which can be used for early diagnosis of different diseases, such as breast and prostate cancer, renal rejection, and liver tumors. CONCLUSIONS: Both nonparametric and parametric approaches for DCE-MRI analysis possess the ability to quantify tissue perfusion.

Power doppler sonography in early renal transplantation: does it differentiate acute graft rejection from acute tubular necrosis?

To evaluate the role of power Doppler in the identification and differentiation between acute renal transplant rejection and acute tubular necrosis (ATN), we studied 67 live donor renal transplant recipients. All patients were examined by spectral and power Doppler sonography. Assessment of cortical perfusion (CP) by power Doppler was subjective, using our grading score system: P0 (normal CP); homogenous cortical blush extending to the capsule, P1 (reduced CP); cortical vascular cut-off at interlobular level, P2 (markedly reduced CP); scattered cortical color flow at the interlobar level. Renal biopsies were performed during acute graft dysfunction. Pathological diagnoses were based on Banff classification 1997. The Mann- Whitney test was used to test the difference between CP grades with respect to serum creatinine (SCr), and resistive index (RI). For 38 episodes of acute graft rejection grade I, power Doppler showed that CP was P1 and RI ranging from 0.78 to 0.89. For 21 episodes of acute graft rejection grade II, power Doppler showed that CP was P1, with RI ranging from 0.88 to >1. Only one case of grade III rejection had a CP of P2. Twelve biopsies of ATN had CP of P0 and RI ranging from 0.80 to 0.89 There was a statistically significant correlation between CP grading and SCr (P <0.01) as well as between CP grading and RI (P <0.05). CP grading had a higher sensitivity in the detection of early acute rejection compared with RI and cross-sectional area measurements. We conclude that power Doppler is a non-invasive sensitive technique that may help in the detection and differentiation between acute renal transplant rejection and ATN, particularly in the early post-transplantation period.

Calcular pulmonary embolism.

Many complications of percutaneous nephrolithotomy(PNL) were reported. In this report, we present a rare complication, which has never been reported. It is the migration of stone fragments into the venous system causing pulmonary emboli. We reviewed the literatures reporting complications following PNL, and there was no available previous report about such complication. It was suspected intraoperative and confirmed radiologically postoperative. In this case, pulmonary emboli have had no clinical consequences and were managed conservatively.

In-vitro and in-vivo diagnostic techniques for prostate cancer: a review.

This paper overviews one of the most important, interesting, and challenging problems in oncology, early diagnosis of prostate cancer. Developing effective diagnostic techniques for prostate cancer is of great clinical importance and can improve the effectiveness of treatment and increase the patient's chance of survival. The main focus of this study is to overview the different in-vitro and in-vivo technologies for diagnosing prostate cancer. This review discusses the current clinically used in-vitro cancer diagnostic tools, such as biomarker tests and needle biopsies and including their applications, advantages, and limitations. Moreover, the current in-vitro research tools that focus on the role of nanotechnology in prostate cancer diagnosis have been detailed. In addition to the in-vitro techniques, the current study discusses in detail developed in-vivo non-invasive state-of-the-art Computer-Aided Diagnosis (CAD) systems for prostate cancer based on analyzing Transrectal Ultrasound (TRUS) and different types of magnetic resonance imaging (MRI), e.g., T2-MRI, Diffusion Weighted Imaging (DWI), Dynamic Contrast Enhanced (DCE)-MRI, and multi-parametric MRI, focusing on their implementation, experimental procedures, and reported outcomes. Furthermore, the paper addresses the limitations of the current prostate cancer diagnostic techniques, outlines the challenges that these techniques face, and introduces the recent trends to solve these challenges, which include biomarkers used in in-vitro lab-on-a-chip nanotechnology-based methods.

Ectopic insertion of the ureter into the seminal vesicle.

We present a case of left ectopic ureter insertion into the left seminal vesicle which is a rare anomaly. The incidence of ectopic insertion of the ureter is more common in females and is usually associated with incontinence, leading to the diagnosis, while in males it is present with infection. Ectopic ureter is defined as abnormal insertion of the ureter, occurring in the posterior urethra in approximately 50% of cases in males. Other sites include the seminal vesicle (approximately one-third), vas deferens, bladder neck, prostate and epididymis, while the urethra and vagina are commonly affected in females. Management is usually addressed to the upper tract only; if there is incontinence it requires removal of the ureteric stump. Our case was initially diagnosed by magnetic resonance imaging and the diagnosis confirmed by computed tomography (CT) guided seminal vesiculography as transrectal guidance for seminal vesiculography was refused by the patient. CT guided seminal vesiculography is less painful and more tolerable than the transrectal route.

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.