Clinical value of prostate segmentation and volume determination on MRI in benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is a nonmalignant pathological enlargement of the prostate, which occurs primarily in the transitional zone. BPH is highly prevalent and is a major cause of lower urinary tract symptoms in aging males, although there is no direct relationship between prostate volume and symptom severity. The progression of BPH can be quantified by measuring the volumes of the whole prostate and its zones, based on image segmentation on magnetic resonance imaging. Prostate volume determination via segmentation is a useful measure for patients undergoing therapy for BPH. However, prostate segmentation is not widely used due to the excessive time required for even experts to manually map the margins of the prostate. Here, we review and compare new methods of prostate volume segmentation using both manual and automated methods, including the ellipsoid formula, manual planimetry, and semiautomated and fully automated segmentation approaches. We highlight the utility of prostate segmentation in the clinical context of assessing BPH.Benign prostatic hyperplasia (BPH) can result in lower urinary tract symptoms, and is one of the most common diseases affecting aging men. BPH can compromise quality of life and is a major healthcare cost. Despite the high prevalence of BPH, few methods of accurately assessing prostate volume are actually used in clinical practice. While patient assessment of urinary symptoms dictates the need for treatment, it is highly subjective, whereas prostate volume change is a more objective measure of treatment response. The most common clinical model for approximating the prostate gland size is the ellipsoid model from transrectal ultrasonography (TRUS) imaging, which has been shown to underestimate prostate volume for prostates larger than 50 mL and to overestimate prostate volume for glands smaller than 30 mL (1). Despite its limitations, the TRUS method of prostate volume assessment is preferred in current clinical practice due to its availability and cost and time efficiency (2). More accurate prostate volume measurement with magnetic resonance (MR) planimetry is time-intensive and, thus, rarely performed.Prostate segmentation is an accurate technique for prostate volume determination that can be used in coregistration with various imaging modalities, such as magnetic resonance imaging (MRI) with positron emission tomography and MRI with ultrasonography. Segmentation can be used for both diagnostic and interventional procedures, including guided biopsies and focal ablation. Newly developed methods of automated prostate segmentation allow for efficient prostate volume determination, thereby enhancing decision support systems and computer-aided diagnosis tools.This article reviews the major methods of prostate volume determination currently in use, including the ellipsoid formula, manual planimetry, and semiautomated and fully automated segmentation. A clinical overview of BPH is also provided to highlight the utility of prostate segmentation in the clinical management of this disease.     

Correlation of serum prostate specific antigen, the volume and the intravesical prostatic protrusion for diagnosing bladder outlet obstruction in patients with benign prostate hyperplasia

Benign prostate hyperplasia (BPH) is common in elderly men. Nevertheless, the pathophysiology of low urinary tract symptoms (LUTS) may not be due only to BPH. Many men with LUTS are submitted to unnecessary medications or surgical interventions because their symptoms have not been correctly evaluated. Can diagnostic test such as serum prostate antigen (PSA), performed by nuclear medicine techniques and the trans-abdominal ultrasound determine with high sensitivity whether LUTS is due exclusively to BPH? The aim of the study was to correlate serum PSA, prostate volume (PV), intravesical prostatic protrusion (IPP), uroflowmetry measuring maximal urine flow/sec (Qmax), and the international prostate symptom score (IPSS) questionnaire, to estimate urine bladder outlet obstruction (BOO), in patients with BPH. A hundred and twelve patients with mean of age 72 +/- 8 years and LUTS were studied. All patients were examined according to the IPSS questionnaire, had their serum PSA tested and also Qmax of prostate volume and IPP by trans-abdominal ultrasound were examined. The patients were separated in groups according to serum PSA values (or= 4.1 ng/ml), prostate volume (PV< 20.20-40 and > 20 ml) and the intravesical prostatic protrusion (IPP < 5.5-10.10 mm). There was a statistical correlation between the BOO and: a) PSA (P = 0.004), b) prostate volume with P of < 0.001) and c) IPP = 0.005. On the contrary, there was no statistical correlation between BOO and IPSS, Qmax with P values 0.228 and 0.745 respectively. Receiving operating curve (ROC) showed that patients with a serum PSA value of 1.5-4 ng/ml, IPP of type II and PV 20-40 ml, had a sensitivity of 48% for PSA, of 50% for PV and of 47% for IPP and a specificity of 75%, 47% and 60% respectively. In conclusion, according to the results of this study, a more objective evaluation of BOO, which is exclusively due to BPH, should include, not only PV but also serum PSA values and IPP.     

Imaging the pediatric prostate

The prostate gland is not often the target of imaging in children but may be imaged during investigation of symptoms related to the lower genitourinary tract such as hematuria, urinary retention, dysuria, and incontinence or during an evaluation for suspected congenital anomalies. Ultrasound and voiding cystourethrography are useful for initial evaluation of congenital and neoplastic disorders of the prostate. MR imaging and CT are useful in delineating more detailed anatomy before surgical planning and in determining the organ of origin in a patient who has a large pelvic mass.     

Prostatic carcinoma and benign prostatic hyperplasia: inability of MR imaging to distinguish between the two diseases

Forty patients with prostatic carcinoma or benign prostatic hyperplasia (BPH) underwent magnetic resonance (MR) imaging of the prostate. In vitro MR images of six prostate specimens were also obtained. The prostatic parenchyma was best evaluated by a T2-weighted spin-echo pulse sequence. The prostate both in patients with prostatic carcinoma and patients with BPH often had an inhomogeneous and nodular appearance on T2-weighted images. While most of the prostatic carcinomas appeared hyperintense relative to muscle and adjacent prostatic parenchyma, some of the hyperplastic nodules had a signal intensity similar to carcinoma. With current imaging techniques, MR imaging cannot differentiate prostatic carcinoma from BPH with certainty.     

Inflammatory disorders of the prostate and the distal genital tract

Inflammatory disease of the prostate and distal genital tract is emerging as a major health problem because it is estimated that up to 15% of adult men may be affected at some point in their lives. Clinically, the diagnosis of "prostatitis" refers to multiple disorders that cause pelvic pain and discomfort, ranging from acute bacterial infection to complex conditions that may not necessarily be caused by prostatic inflammation. Because the traditional etiology-based classification system did not always correlate with symptoms and therapeutic efficacy, a new classification of prostatitis has been suggested by the National Institutes of Health. New imaging techniques such as high-resolution transrectal ultrasonography (TRUS) and MR imaging provide exquisite anatomic detail and often play a crucial role in the evaluation of these patients.     

Quality of Life and Clinical Symptom Improvement Support Prostatic Artery Embolization for Patients with Acute Urinary Retention Caused by Benign Prostatic Hyperplasia

PurposeTo show that prostatic artery embolization (PAE) improves quality of life (QoL) and lower urinary tract symptoms in patients with acute urinary retention caused by benign prostatic hyperplasia (BPH).Materials and MethodsThis was a single-center prospective study of PAE in 11 patients with BPH managed with indwelling urinary catheters. International Prostate Symptom Score (IPSS), ultrasound, magnetic resonance (MR) imaging, QoL, and urodynamic tests were used to assess outcomes. Prostate size ranged from 30 to 90 g, and embolizations were performed with 300–500-μm Embosphere microspheres.ResultsThe rate of technical success (ie, bilateral PAE) was 75%, and the rate of clinical success (ie, catheter removal and symptom improvement) was 91% (10 of 11 patients). Postembolization syndrome manifested as mild pain in the perineum, retropubic area, and/or urethra. Ten of 11 patients urinated spontaneously after Foley catheter removal 4–25 days after PAE (mean, 12.1 d). No major complications were observed. Follow-up ranged from 19 to 48 months. In an asymptomatic patient, a discrete area of hypoperfusion suggesting small ischemia of the bladder was observed on 30-day MR imaging follow-up, but the bladder was normal on 90-day MR imaging. After 1 year, mean prostate volume reduction was greater than 30%, symptoms were mild (mean IPSS, 2.8±2.1; P = .04), no erectile dysfunction was observed, and QoL improved significantly (mean, 0.4±0.5; P = .001) using the paired t test.ConclusionsPatients with severe symptoms and acute urinary retention caused by BPH can be treated safely by PAE, which improves clinical symptoms and QoL.     

Prostatic Artery Embolization to Achieve Freedom from Catheterization in Patients with Acute Urinary Retention Caused by Benign Prostatic Hyperplasia

PurposeTo determine the ability of prostatic artery embolization (PAE) to achieve freedom from catheterization in patients with acute urinary retention (AUR) caused by benign prostatic hyperplasia (BPH).Materials and MethodsThis retrospective single-center study was performed between June 2014 and March 2019 in patients with lower urinary tract symptoms (LUTS) caused by BPH. PAE was performed in 154 eligible patients, of which 76 suffered from spontaneous AUR and had indwelling catheters placed and kept until the procedure, owing to clinical failure in the removal of the previous intermittent catheter. Each patient was followed for at least 12 months. The first trial without catheter was performed 3 days after PAE. Successful catheter removal within the first 30 days after PAE was considered a clinical success. The rate of patients free from catheterization, LUTS relief, prostate volume, and adverse events was recorded.ResultsClinical success was achieved in 70 (92.1%) patients. The rates of freedom from catheterization were 90.3% (65/72), 83.3% (60/72), and 80.6% (58/72) at 3-, 6-, and 12-months follow-up, respectively. The median elapsed time from PAE to catheter removal was 10 days. However, 18 patients needed further interventions. Symptom scores revealed a continuous improvement in urinary symptoms. The mean prostate volume showed a statistically significant decrease at 3 and 12 months compared with its baseline value. No severe adverse events occurred.ConclusionsPAE can achieve freedom from catheterization in patients with AUR caused by BPH.     

良性前列腺增生症合并慢性前列腺炎的临床研究

目的探讨前列腺增生症(BPH)与慢性前列腺炎(CP)的关系及临床特点。方法对2009年1月—2011年12月我院泌尿外科收治的96例良性BPH患者的年龄、病程、国际前列腺症状评分(IPSS)、前列腺体积、PSA水平等项目进行回顾性分析研究。结果 96名研究对象总体的慢性前列腺炎的发生率为68.75%。合并慢性前列腺炎患者的年龄、病程、IPSS评分、前列腺体积及PSA水平显著高于单纯前列腺增生组。结论前列腺炎症在BPH的进展中起着重要作用,同时炎症可能会加重BPH患者的下尿路症状,应给予积极治疗。     

Prostatic Artery Embolization as an Alternative to Indwelling Bladder Catheterization to Manage Benign Prostatic Hyperplasia in Poor Surgical Candidates

To prospectively assess discontinuation of indwelling bladder catheterization (IBC) and relief of lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH) following prostate artery embolization (PAE) in poor surgical candidates. Patients ineligible for surgical intervention were offered PAE after at least 1 month of IBC for management of urinary retention secondary to BPH; exclusion criteria for PAE included eligibility for surgery, active bladder cancer or known prostate cancer. Embolization technical and clinical success were defined as bilateral prostate embolization and removal of IBC, respectively. Patients were followed for at least 6 months and evaluated for International Prostate Symptom Score, quality of life, prostate size and uroflowmetric parameters. A total of 43 patients were enrolled; bilateral embolization was performed in 33 (76.7%), unilateral embolization was performed in 8 (18.6%), and two patients could not be embolized due to tortuous and atherosclerotic pelvic vasculature (4.7%). Among the patients who were embolized, mean prostate size decreased from 75.6 ± 33.2 to 63.0 ± 23.2 g (sign rank p = 0.0001, mean reduction of 19.6 ± 17.3%), and IBC removal was achieved in 33 patients (80.5%). Clavien II complications were reported in nine patients (21.9%) and included urinary tract infection (three patients, 7.3%) and recurrent acute urinary retention (six patients, 14.6%). Nine patients (22.0%) experienced post-embolization syndrome. PAE is a safe and feasible for the relief of LUTS and IBC in highly comorbid patients without surgical treatment options.     

Prostatic Artery Embolization for the Treatment of Recurrent Lower Urinary Tract Symptoms following Transurethral Resection of the Prostate

PurposeTo evaluate the safety and efficacy of prostatic artery embolization (PAE) in patients with recurrent lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH) who underwent a previous transurethral resection of the prostate (TURP).Materials and MethodsThis retrospective study analyzed 15 of 19 patients who underwent PAE for recurrent LUTS after TURP between February 2014 and April 2019. The technical and clinical success rates and complications related to the procedure were recorded. International Prostate Symptom Score (IPSS), quality of life (QoL), and prostatic volume (PV) were evaluated at baseline and 3- and 12-mo follow-up.ResultsThe intervals from TURP to recurrent symptoms and from TURP to PAE were 4.3 y ± 3.2 and 5.6 y ± 3.8, respectively. Technical success was achieved in all patients. The clinical success rate for LUTS relief at 12 mo was 93.3% (14 of 15). IPSS significantly reduced from 22.5 ± 4.1 at baseline to 9.9 ± 4.9 at 12-mo follow-up, and QoL score improved from 4.7 ± 1.0 to 2.1 ± 1.1 (P < .05 for both). There was a significant mean reduction of 26.6% in PV at 12 mo, improving from 100.7 cm³ ± 38.5 to 73.9 cm³ ± 29.4 (P < .05). No severe complications were encountered.ConclusionsPAE may be a safe and effective treatment option for the management of recurrent LUTS secondary to BPH in patients who have previously undergone TURP.     

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.     

低场磁共振T1 FLAIR在前列腺检查中的应用(与SE序列比较)

目的：评估低场磁共振T1 FLAIR对前列腺检查的价值。方法：分析50例志愿者的前列腺MRI正常解剖;评估42例前列腺癌,76例前列腺增生,48例前列腺炎的磁共振诊断价值。结果：T1 FLAIR在显示前列腺内部结构、包膜和神经血管束方面与SE T1 WI(T1—SE)在统计学上差异有显著性意义;T1 FLAIR对疾病诊断价值的评分明显高于T1-SE。结论：T1 FLAIR在前列腺检查中有较高的使用价值。     

Transrectal ultrasonography and ultrasound-guided biopsies of the prostate gland: how, when, and where

TRUS- and ultrasound-guided biopsies of the prostate gland have become a valuable tool in the detection and management of prostate cancer and other benign prostatic pathology.Detailed knowledge of prostatic anatomy, TRUS examination technique, the various imaging findings, as well as the biopsy technique contribute to improved treatment planning and therapeutic outcome.     

Randomized Comparison of Prostatic Artery Embolization versus Transurethral Resection of the Prostate for Treatment of Benign Prostatic Hyperplasia

PurposeTo compare clinical and functional outcomes of prostatic artery embolization (PAE) with those of transurethral resection of the prostate (TURP) for the treatment of lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH).Materials and MethodsNoninferiority randomized trial was conducted involving men over 60 years of age with LUTS secondary to BPH. From November 2014 to January 2017, 45 patients were randomized to PAE (n = 23) or to TURP (n = 22). PAE was performed with 300- to 500-μm microspheres with the patient under local anesthesia, whereas bipolar TURP was performed with the patients under spinal or general anesthesia. Primary outcomes were changes in peak urinary flow (Q_max) and international prostate symptoms score (IPSS) from baseline to 12 months. Quality of life (QoL), and prostate volume (PV) changes from baseline to 12 month were secondary outcomes. Adverse events were compared using the Clavien classification.ResultsMean Q_max increased from 6.1 mL/s in the PAE group and from 9.6 mL/s in the TURP patients (P = .862 for noninferiority), and mean IPSS reduction was 21.0 points for PAE and 18.2 points for TURP subjects (P = .080) at 12 months. A greater QoL improvement was reported in the PAE group (3.78 points for PAE and 3.09 points for TURP; P = .002). Mean PV reduction was 20.5 cm³ (34.2%) for PAE subjects and 44.7 cm³ (71.2%) for TURP subjects (P < .001). There were fewer adverse events reported in the PAE group than in the TURP group (n = 15 vs n = 47; P < .001).ConclusionsReduction of LUTS in the PAE group was similar to that in the TURP group at 12 months, with fewer complications secondary to PAE. Long-term follow-up is needed to compare the durability of the symptomatic improvement from each procedure.     

Brachytherapy for prostate cancer: endorectal MR imaging of local treatment-related changes

PURPOSE: To determine the local treatment-related endorectal magnetic resonance (MR) imaging findings after brachytherapy for prostate cancer. MATERIALS AND METHODS: Endorectal MR imaging was performed in 35 consecutive patients at a mean interval of 12 months (range, 1-31 months) after brachytherapy for prostate cancer. Transverse T1-weighted and high-spatial-resolution transverse and coronal T2-weighted images were acquired. Two readers reviewed MR image quality and findings, with discrepancies resolved by consensus. Posttreatment urinary symptoms in patients (n = 24) were documented by using chart review. RESULTS: All studies were of diagnostic quality. On T2-weighted images, prostatic findings consisted of diffuse low signal intensity (n = 35) and indistinct zonal anatomy (n = 34). Intra- and extraprostatic seed locations could be distinguished. The most common extraprostatic site of seed implantation was the neurovascular bundles (n = 35, bilateral in 32). The most common extraprostatic tissue finding was increased signal intensity on T2-weighted images in the levator ani muscle (n = 34) and the genitourinary diaphragm (n = 28). Postbrachytherapy urinary symptoms showed no demonstrable correlation with periurethral or genitourinary diaphragm seed implantation or with signal intensity change in the genitourinary diaphragm. CONCLUSION: Endorectal MR imaging can be used to evaluate seed distribution and to demonstrate treatment-related changes after brachytherapy for prostate cancer.     

Prostate cancer imaging

As prostate cancer is a biologically heterogeneous disease for which a variety of treatment options are available, the major objective of prostate cancer imaging is to achieve more precise disease characterization. Magnetic resonance imaging (MRI) may enhance the staging of prostate cancer compared with clinical evaluation, transrectal ultrasound, or computed tomography (CT), and allows concurrent evaluation of prostatic, periprostatic, and pelvic anatomy. In clinical practice, the fusion of MRI or dynamic contrast-enhanced MRI (DCE-MRI) with MR spectroscopic imaging (MRSI) is improving the evaluation of cancer location, size, and extent, while providing an indication of tumor aggressiveness. Pretreatment knowledge of these prognostic variables is essential for achieving minimally invasive, patient-specific therapy.     

MRT-gezielte interventionelle Verfahren zur Abkl?rung des Prostatakarzinoms

In recent years magnetic resonance imaging (MRI) has been increasingly established in the diagnosis of prostate cancer in addition to transrectal ultrasonography (TRUS). The use of T2-weighted imaging allows an exact delineation of the zonal anatomy of the prostate and its surrounding structures. Other MR imaging tools, such as dynamic contrast-enhanced T1-weighted imaging or diffusion-weighted imaging allow an inference of the biochemical characteristics (multiparametric MRI). Prostate cancer, which could only be diagnosed using MR imaging or lesions suspected as being prostate cancer, which are localized in the anterior aspect of the prostate and were missed with repetitive TRUS biopsy, need to undergo MR guided biopsy. Recent studies have shown a good correlation between MR imaging and histopathology of specimens collected by MR-guided biopsy. Improved lesion targeting is therefore possible with MR-guided biopsy. So far data suggest that MR-guided biopsy of the prostate is a promising alternative diagnostic tool to TRUS-guided biopsy.     

Utility of MR Angiography in the Identification of Prostatic Artery Origin Prior to Prostatic Artery Embolization

In 17 patients who underwent prostate artery embolization for treatment of lower urinary tract symptoms, the accuracy of preprocedural magnetic resonance (MR) angiography was retrospectively compared with intraprocedural digital subtraction angiography (DSA) in the identification of prostatic artery origin. Of 34 vessels, 26 MR angiography identified origins (76.5%) were confirmed by DSA at the time of embolization. Although image postprocessing is required, the ability of MR angiography to accurately identify prostatic artery origins prior to embolization is useful in treatment planning and can obviate the need for separate computed tomographic angiography, thus reducing both radiation dose and time demand on patients.     

Radiologic anatomy of the prostate gland: a clinical approach

Familiarity with normal anatomy is critical to interpretation of imaging of the prostate and peri-prostatic structures. This is especially true for MR imaging, which depicts these structures with exquisite detail due to high spatial resolution, superior contrast resolution, multiplanar capability, and large field of view. Anatomic understanding plays a key role in the assessment and management of prostatic disease, and allows evaluation of anatomic disturbances that may result from prostatic disease or therapy, and which may have functional consequences, particularly for continence and potency.     

Correlation of power Doppler with microvessel density in assessing prostate needle biopsy

AIM: To correlate hypervascular power Doppler ultrasonography with the histological evaluation of microvasculature in the prostate using trans-rectal ultrasound (TRUS)-guided needle biopsy. MATERIALS AND METHODS: Ninety-six patients with a lower urinary tract symptoms (LUTS) and prostate specific antigen (PSA) value more than 4 ng/ml were evaluated using power Doppler ultrasonography before biopsy. The vascularity of the peripheral zone was graded on a scale of PZ0 to PZ2. Core needle biopsies were immunostained with CD31(DAKO) and counting was performed manually on separate high power fields (HPF; x 400) in areas containing the highest number of vessels. RESULTS: There was a significant correlation between the grading system used for power Doppler and the microvessel density (MVD; PZ0 28.61 +/- 8.97,PZ1 36.00 +/- 12.11 & PZ2 64.008 +/- 15.86; p < 0.001). There was also a significant difference in MVD between benign, malignant and tissue cores with atypia and prostatic intra-epithelial neoplasia (PIN; p < 0.001 and p < 0.018 respectively). There was a significant correlation between malignant tissue having a higher Gleason score and increased MVD (p < 0.001) Furthermore, cancer biopsies having a high flow PZ2 are nearly twice as likely (63.2%) to have a Gleason score of 7 or more when compared those having a Gleason score of less than 7 (36.8%). CONCLUSION: The grading system of assessing the power Doppler flow signals appears to be of value as an indicator of MVD. It also correlates with a higher Gleason score and this may reflect the clinical outcome in prostate cancer. It deserves further study and evaluation as a prognostic indicator.