Time‐dependent change of blood flow in the prostate treated with high‐intensity focused ultrasound

Avascular areas on contrast‐enhanced magnetic resonance imaging have been considered to be areas of localized prostate cancer successfully treated by high‐intensity focused ultrasound. However, the optimal timing of magnetic resonance imaging has not been discussed. The thermal effect of high‐intensity focused ultrasound is degraded by regional prostatic blood flow. Conversely, the mechanical effect of high‐intensity focused ultrasound (cavitation) is not affected by blood flow, and can induce vessel damage. In this series, the longitudinal change of blood flow on contrast‐enhanced magnetic resonance imaging was observed from postoperative day 1 to postoperative day 14 in 10 patients treated with high‐intensity focused ultrasound. The median rates of increase in the non‐enhanced volume of the whole gland, transition zone and peripheral zone from postoperative day 1 to postoperative day 14 were 36%, 39%, and 34%, respectively. In another pathological analysis of the prostate tissue of 17 patients immediately after high‐intensity focused ultrasound without neoadjuvant hormonal therapy, we observed diffuse coagulative degeneration and partial non‐coagulative prostate tissue around arteries with vascular endothelial cell detachment. These observations on contrast‐enhanced magnetic resonance imaging support a time‐dependent change of the blood flow in the prostate treated with high‐intensity focused ultrasound. Additionally, our pathological findings support the longitudinal changes of these magnetic resonance imaging findings. Further large‐scale studies will investigate the most appropriate timing of contrast‐enhanced magnetic resonance imaging for evaluation of the effectiveness of high‐intensity focused ultrasound for localized prostate cancer.     

高强度超声聚能系统治疗激素难治性前列腺癌临床疗效观察

目的:探讨经直肠高强度聚焦超声(high-intensity focused ultrasound,HIFU)治疗激素难治性前列腺癌的有效性及安全性.方法:采用美国Focus Surgery公司生产的第三代HIFU Sonablate-500型治疗仪,对22例激素难治性前列腺癌患者进行治疗.根据直肠指检和经直肠前列腺B超检查前列腺肿块大小、血清PSA、ECT骨扫描等将疗效分为完全反应(CR)、部分反应(PR)、病情稳定(SD)、病情恶化(PD).主观症状根据骨痛、排尿异常、血尿等症状的变化分为症状消失、症状改善、症状平稳、症状加剧.结果:经HIFU治疗,CR 6例,占27.3%(6/22);PR 11例,占50.0%(11/22);SD 4例,占18.2%(4/22);PD1例,占4.5%(1/22).总有效率(CR PR)达到77.3%(17/22).主观症状消失9例,占40.9%(9/22);症状改善6例,占27.3%(6/22);症状稳定3例,占13.6%(3/22);症状加剧4例,占18.2%(4/22).主观症状总改善率(症状消失 症状改善)达到68.2%(15/22).3例伴有血尿者均控制良好.术后并发症:3例发生附睾炎,无尿道狭窄、尿失禁、阳痿、尿道直肠瘘并发症发生.结论:HIFU对激素难治性前列腺癌的治疗有效、安全,为微创治疗激素难治性前列腺癌提供了新的途径.     

Multiparametric Magnetic Resonance Imaging for the Detection of Clinically Significant Prostate Cancer: What Urologists Need to Know. Part 2: Interpretation

BackgroundThere is large variability among radiologists in their detection of clinically significant (cs) prostate cancer (PCa) on multiparametric magnetic resonance imaging (mpMRI).ObjectiveTo reduce the interpretation variability and achieve optimal accuracy in assessing prostate mpMRI.Design, setting, and participantsHow the interpretation of mpMRI can be optimized is demonstrated here. Whereas part 1 of the “surgery-in-motion” paper focused on acquisition, this paper shows the correlation between (ab)normal prostate anatomical structures and image characteristics on mpMRI, and how standardized interpretation according to Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) should be performed. This will be shown in individual patients.Surgical procedureTo detect csPCa, three mpMRI “components” are used: “anatomic” T2-weighted imaging, “cellular-density” diffusion-weighted imaging, and “vascularity” dynamic contrast-enhanced MRI.MeasurementsBased on PI-RADS v2, the accompanying video shows how mpMRI interpretation is performed. Finally, the role of mpMRI in detecting csPCa is briefly discussed and the main features of the recently introduced PI-RADS v2.1 are evaluated.Results and limitationsWith PI-RADS v2, it is possible to quantify normal and abnormal anatomical structures within the prostate based on its imaging features of the three mpMRI “components.” With this knowledge, a more objective evaluation of the presence of a csPCa can be performed. However, there still remains quite some space to reduce interobserver variability.ConclusionsFor understanding the interpretation of mpMRI according to PI-RADS v2, knowledge of the correlation between imaging and (ab)normal anatomical structures on the three mpMRI components is needed.Patient summaryThis second surgery-in-motion contribution shows what structures can be recognized on prostate magnetic resonance imaging (MRI). How a radiologist performs his reading according to the so-called Prostate Imaging Reporting and Data System criteria is shown here. The main features of these criteria are summarized, and the role of prostate MRI in detecting clinically significant prostate cancer is discussed briefly.     

MR T2WI高信号环征对高强度聚焦超声消融子宫肌瘤即刻疗效的影响

目的观察MR T2WI高信号环征(T2-rim sign)对高强度聚焦超声(HIFU)治疗子宫肌瘤即刻疗效的影响。方法回顾性分析360例接受HIFU治疗的子宫肌瘤患者,以治疗后肌瘤非灌注区体积(NPV)与治疗前肌瘤体积的百分比(NPV%)判断消融效果,根据术前是否存在T2-rim sign分为T2-rim sign组和无T2-rim sign组,以单因素及多因素Logistic回归分析NPV%的可能影响因素。结果消融后即刻超声造影显示肌瘤血供明显减少,60例NPV%75%,300例≥75%,其间肌瘤位置、辐照时间、治疗强度、MR T2WI信号强度及有无T2-rim sign差异均有统计学意义(P均0.05)。HIFU消融肌瘤NPV%与MR T2WI信号强度、T2-rim sign、辐照时间及治疗强度有关(P均0.05);辐照时间、治疗强度及T2-rim sign是影响HIFU消融肌瘤NPV%的独立危险因素(P均0.05)。相比无T2-rim sign组,T2-rim sign组辐照时间、治疗强度均增加,NPV%降低(P均0.05)。结论 T2-rim sign为HIFU治疗子宫肌瘤即刻疗效的影响因素;具有该特征的子宫肌瘤患者亦可自HIFU治疗中获益。     

Targeted prostate biopsy： value of multiparametric magnetic resonance imaging in detection of localized cancer

Prostate cancer is the second most common cancer in men, with 1.1 million new cases worldwide reported by the World Health Organization in one recent year. Transrectal ultrasound （TRUS）-guided biopsy has been used for the diagnosis of prostate cancer for over 2 decades, but the technique is usually blind to cancer location. Moreover, the false negative rate of TRUS biopsy has been reported to be as high as 47%. Multiparametric magnetic resonance imaging （mp-MRI） includes T1- and T2-weighted imaging as well as dynamic contrast-enhanced （DCE） and diffusion-weighted imaging （DWI）. mp-MRI is a major advance in the imaging of prostate cancer, enabling targeted biopsy of suspicious lesions. Evolving targeted biopsy techniquesmincluding direct in-bore biopsy, cognitive fusion and software-based MRI-ultrasound （MRI-US） fusion--have led to a several-fold improvement in cancer detection compared to the earlier method. Importantly, the detection of clinically significant cancers has been greatly facilitated by targeting, compared to systematic biopsy alone. Targeted biopsy via MRI-US fusion may dramatically alter the way prostate cancer is diagnosed and managed.     

Endorectal magnetic resonance imaging and magnetic resonance spectroscopy to monitor the prostate for residual disease or local cancer recurrence after transrectal high-intensity focused ultrasound

OBJECTIVE

To assess the role of magnetic resonance imaging (MRI) for evaluating changes in the prostate after transrectal high‐intensity focused ultrasound (HIFU) for treating prostate cancer, correlating the findings with histology to assess its possible role in predicting the outcome, evaluating residual cancer or local recurrence of disease.

PATIENTS AND METHODS

Ten patients with prostate cancer were assessed with MR and MR spectroscopy (MRS) before and at 1, 4 and 12 months after HIFU, assessing the glandular volume and MRI and MRS data after HIFU. These data were correlated with the prostate‐specific antigen (PSA) levels at each examination (suspicious for residual cancer if >0.5 ng/mL) and with histological findings of prostate biopsy sampling at 6–8 months (random or targeted at suspicious MR areas).

RESULTS

Variations in volume during the follow‐up were not associated with treatment outcome. MRI was suspicious for residual cancer in one patient at 1 month and in another two at 4 months; in all three patients (one with a PSA level of <0.5 ng/mL) targeted biopsies were positive for cancer. MRI was negative in seven patients; in six of these (one with a PSA level of >0.5 ng/mL) random biopsies were negative, and in one the random biopsies were positive for residual cancer. At 4 months there was a statistically significant difference (P = 0.015) between patients responsive to treatment and those with persistent disease, by combining negative MRI with a PSA level of <0.5 ng/mL; MRS data were suitable for analysis only in three patients with partial necrosis.

CONCLUSION

Our preliminary data support the role of MRI in association with PSA levels as a useful and accurate tool in the follow‐up of patients treated with HIFU for prostate cancer. However, considering the economic issue, it should not be used routinely and should be limited to detecting residual cancer (in patients with a PSA level of >0.5 ng/mL) with the main purpose of improving the detection rate of transrectal ultrasonography (TRUS)‐guided prostate biopsy. MRS data had no additional value over MRI. Further evaluation is needed to compare the use of contrast media and other techniques (e.g. colour Doppler TRUS) in detecting residual or local recurrent cancer.     

Initial clinical experience with real-time transrectal ultrasonography-magnetic resonance imaging fusion-guided prostate biopsy

OBJECTIVE

To evaluate the feasibility and utility of registration and fusion of real‐time transrectal ultrasonography (TRUS) and previously acquired magnetic resonance imaging (MRI) to guide prostate biopsies.

PATIENTS AND METHODS

Two National Cancer Institute trials allowed MRI‐guided (with or with no US fusion) prostate biopsies during placement of fiducial markers. Fiducial markers were used to guide patient set‐up for daily external beam radiation therapy. The eligible patients had biopsy‐confirmed prostate cancer that was visible on MRI. A high‐field (3T) MRI was performed with an endorectal coil in place. After moving to an US suite, the patient then underwent TRUS to visualize the prostate. The US transducer was equipped with a commercial needle guide and custom modified with two embedded miniature orthogonal five‐degrees of freedom sensors to enable spatial tracking and registration with MR images in six degrees of freedom. The MRI sequence of choice was registered manually to the US using custom software for real‐time navigation and feedback. The interface displayed the actual and projected needle pathways superimposed upon the real‐time US blended with the prior MR images, with position data updating in real time at 10 frames per second. The registered MRI information blended to the real‐time US was available to the physician who performed targeted biopsies of highly suspicious areas.

RESULTS

Five patients underwent limited focal biopsy and fiducial marker placement with real‐time TRUS‐MRI fusion. The Gleason scores at the time of enrolment on study were 8, 7, 9, 9, and 6. Of the 11 targeted biopsies, eight showed prostate cancer. Positive biopsies were found in all patients. The entire TRUS procedure, with fusion, took ≈10 min.

CONCLUSION

The fusion of real‐time TRUS and prior MR images of the prostate is feasible and enables MRI‐guided interventions (like prostate biopsy) outside of the MRI suite. The technique allows for navigation within dynamic contrast‐enhanced maps, or T2‐weighted or MR spectroscopy images. This technique is a rapid way to facilitate MRI‐guided prostate therapies such as external beam radiation therapy, brachytherapy, cryoablation, high‐intensity focused ultrasound ablation, or direct injection of agents, without the cost, throughput, or equipment compatibility issues that might arise with MRI‐guided interventions inside the MRI suite.     

DWI在HIFU消融治疗子宫肌瘤术后评价中的应用

目的探讨DWI在高强度聚焦超声(HIFU)消融治疗子宫肌瘤术后评价中的应用价值。方法对270例患者(共270个子宫肌瘤)行HIFU消融治疗,于术前及术后分别行增强磁共振成像(CE-MRI)及DWI检查,其中A组98例术后MRI于消融当日(术后6h内)完成,B组172例术后MRI于消融后1~2天(24~48h)完成。分析病灶ADC值变化,观察DWI特征。并测量DWI信号改变区体积及CE-MRI无灌注区体积(NPV),分析二者间的相关性。结果 DWI示HIFU消融后子宫肌瘤呈靶环样改变。两组患者消融前子宫肌瘤ADC值差异无统计学意义(t=-0.322,P=0.748),消融后ADC值差异有统计学意义(t=8.874,P0.001)。A组术后ADC值较术前减低(t=3.500,P=0.001),B组术后ADC值较术前增高(t=-16.842,P0.001)。HIFU消融后DWI信号改变区中位体积为50.78cm3(四分位间距30.03~89.60cm3),CE-MRI的NPV为52.65cm3(四分位间距30.03~89.60cm3),差异无统计学意义(z=-1.357,P=0.175),且二者呈正相关关系(r=0.989,P0.001)。结论 DWI可用于HIFU消融治疗子宫肌瘤术后短期疗效的评价。     

Relationship between age and prostate size

In a community-based study, the relationship between age and human prostate size was investigated in a population of men between the ages of 40 and 70 years to determine the normal prostate increase curve equation. One thousand male volunteers were randomly recruited from the Shanghai community, and the length, width, height, volume of the transition zone (TZ) and the whole prostates were measured by transrectal ultrasound (TRUS). Each volunteer was evaluated by the International Prostate Symptom Score (IPSS). Among those who completed the examination, the mean prostate parameters were all positively associated with increased age. There were statistically significant differences between each age group (P<0.05). The mean transition zone volume (TZV) had a higher increase rate with age than the mean total prostate volume (TPV), indicating that the enlargement of the TZ contributed the most to the increase in TPV. While all prostate parameters were positively correlated with the IPSS, the strongest correlation was associated with the TZ length (TZL) and TZV. The growth curve equations for prostate width, height and length were also positively associated with increasing age.     

MRI/US成像融合引导的经会阴前列腺穿刺活检的单中心研究

目的:评估磁共振/超声(MRI/US)成像融合引导的经会阴前列腺穿刺活检对前列腺癌诊断的价值。方法:回顾性分析2014年9月~2016年3月我院行MRI/US成像融合引导的经会阴前列腺穿刺活检的121例患者资料,每例均行12针系统性穿刺活检(SB)+每个目标靶点(ROI)2针靶向穿刺活检(TB)。活检标本行病理学分析,获知Gleason评分和阳性单针癌组织长度。记录所有患者的临床、影像及病理资料,采用t检验、秩和检验、卡方检验等统计学方法对各项数据进行分析对比。结果:TB的前列腺癌单针阳性率(20.0%)以及高危前列腺癌单针阳性率(10.3%)均明显高于SB(12.7%和5.5%),差异均有统计学意义(P=0.001和P=0.002);TB的阳性单针癌组织长度高于SB,差异有统计学意义(P=0.046);TB的阳性针癌组织主要分化程度的Gleason评分、次要分化程度的Gleason评分、Gleason总评分均高于SB,但差异无统计学意义(P>0.05)。结论:MRI/US成像融合引导的前列腺穿刺活检中的TB较SB能够更有效地检出高危前列腺癌。在条件允许的情况下可推广应用MRI/US成像融合引导的前列腺穿刺活检技术。     

磁共振导航高强度聚焦超声的临床应用及进展

磁共振导航高强度聚焦超声（MRgHIFU）是基于磁共振导航下解剖定位、实时测温和高强度聚焦超声组合的无创治疗方法,相对于外科手术更具优势。该技术已在临床应用于子宫肌瘤、子宫腺肌症、乳腺肿瘤、疼痛性骨转移、前列腺癌、肝肿瘤、脑肿瘤的消融治疗,而在功能性神经外科治疗和急性脑血管意外治疗领域中的临床前研究也在进行之中。本文对MRgHIFU的治疗原理、临床应用现状及进展进行综述。     

Technique for a hybrid system of real‐time transrectal ultrasound with preoperative magnetic resonance imaging in the guidance of targeted prostate biopsy

Diagnostic magnetic resonance imaging (MRI) for prostate has achieved increasingly higher levels of accuracy. Because real‐time MR‐guided targeted biopsy is still a complicated and expensive procedure, there is considerable interest in a technique of MR/transrectal ultrasound (TRUS) hybridized image‐guided biopsy. However, because the 3‐D shapes of the prostate at the time of image‐acquisition at preoperative MRI are likely to be different from the intra‐operative TRUS images, the precise registration of each 3‐D volume data is critical. To reduce the potential errors in registration of TRUS with MRI, we introduce new procedural techniques in a rigid image fusion technique. First, preoperative MR images were obtained with a specifically‐made plastic outer‐frame, with exactly the same shape as the real TRUS probe, placed in the rectum, in order to simulate the deformation of the prostate caused by the absence or presence of a TRUS probe during the acquisition of MR or TRUS images. Second, instead of using a single plane of longitudinal image, we applied biplane TRUS images to be shown in parallel on a multiplanar display with corresponding reconstructed MRI, in order to register both horizontal and longitudinal images of the prostate simultaneously, thereby achieving improved 3‐D anatomical matching.     

Correlation between the total volume,transitional zone volume of the prostate,transitional prostate zone index and lower urinary tract symptoms (LUTS)

Objectives Currently available studies show controversial data between the symptoms of the lower urinary tract and the volume of the prostate gland. The objective of the present study is to evaluate the relationship between the score of the lower urinary tract symptoms assessed according to the International Prostate Symptoms Score (IPSS) and the total (TV) and transitional (TZV) zone volume of the prostate and transitional prostate zone index (TZI). Materials and methods From 223 men with a mean age of 59.3 years (varying from 50 to 75), the scores of lower urinary tract symptoms, measured by the IPSS and TV and TZV, determined by transrectal ultrasonographies, were obtained. Furthermore, the TZI was determined in all cases by the TZV to TV rate of the prostate. The relationship between TV, TZV, and TZI and the data obtained using the symptoms score was statistically determined. Results The TV of the prostate were 25.5 ± 10.3, 25.0 ± 9.3, and 28.9 ± 13.5 g in individuals with mild, moderate, and severe symptoms, respectively (P = 0.15). Similarly, there was no significant difference when the TZV (7.6 ± 6.3, 7.6 ± 5.8, and 9.6 ± 6.8 g, respectively; P = 0.22) and the TZI (0.26 ± 0.1, 0.27 ± 0.1, and 0.30 ± 0.1, respectively; P = 0.33) were compared in the groups of men with mild, moderate, and severe symptoms of urinary difficulty. However, the quality of life (QoL) scores presented progressively worse values (1.7 ± 1.3, 3.1 ± 1.4, and 4.4 ± 1.2) as the severity of the lower urinary tract symptoms became worse (P < 0.001). The Pearson correlation coefficient between the TV (r = 0.15; P = 0.02), TZV (r = 0.16; P = 0.02), and the TZI (r = 0.14; P = 0.03) with the prostate symptom scores showed low values although they were positive and statistically significant. The highest correlation was observed when the QoL related to urinary symptoms and symptom scores (r = 0.61; P < 0.001) was analyzed. Conclusions A low correlation was found between the score lower urinary tract symptoms assessed by IPSS and the different volumes of the prostate gland (TV, TZV) and prostate TZI, and, on the other hand, an inverse correlation between the intensity of urinary symptoms and QoL, supporting the idea of multifactorial aspects related to the genesis of urinary symptoms in men.