磁共振尿路成像对泌尿系疾病的诊断价值

目的 :探讨磁共振尿路成像 (MRU)的临床应用及其对泌尿系疾病的诊断价值。方法 :泌尿系疾病 60例 ,其中输尿管畸形 14例 ,尿路结石 18例 ,尿路肿瘤 10例 ,炎症及结核 8例 ,外压性及手术后输尿管狭窄 4例 ,神经性膀胱及膀胱憩室 6例 .所有病例均行MRI检查及应用重T2 WI快速自旋回波序列行MRU检查 ,所有图像均作最大信号投影 (MIP)后处理重建。结果 :48例MRU显示尿道梗阻 ,MRU均能明确显示梗阻部位及程度 ,对静脉尿路造影 (IVU)不能显影者有优越性 ,定位诊断正确率 10 0 %,结合常规MRI定性诊断率达到 80 %。结论 :MRU是一种简便、无创伤检查技术 ,对多种泌尿系疾病尤其是尿道梗阻具有较高诊断价值     

IVU、SCTU及MRU对梗阻性尿路疾病诊断能力比较

目的比较静脉肾盂造影(IVU)、多层螺旋CT尿路造影(SCTU)及磁共振泌尿系水成像(MRU)对梗阻性尿路疾病的诊断能力,为临床选择合理检查方案提供理论依据。方法对62例经手术病理或经临床治疗随访证实的梗阻性尿路疾病患者影像资料进行回顾性分析,本组病例均行IVU检查,25例患者行SCTU检查,49例患者行MRU检查,12例患者同时行上述3种方法检查。结果 8例肾盂-输尿管移行部狭窄,IVU显示2例,7例包括IVU未显示病例MRU可清晰显示,1例CTU显示不清,不能明确诊断;19例输尿管结石病例,IVU显示9例,10例IVU未显示梗阻原因患者行CTU检查均清晰显示,13例行MRU检查,7例显示;15例输尿管肿瘤,7例行CTU检查,12例行MRU检查均显示清晰;11例输尿管外源性压迫或侵犯病例,IVU表现为肾积水,3例行CTU检查,10例行MRU检查均可清晰显示;9例输尿管炎性病变,IVU表现为肾积水,4例行CTU检查,2例显示清晰,2例与肿瘤不易鉴别,7例行MRU检查,均显示清晰。结论 IVU在梗阻性尿路疾病中主要用来筛查,当怀疑梗阻原因是结石引起时,应首选CTU检查,当怀疑梗阻原因是先天狭窄或肿瘤性病变时应首选MRU。     

磁共振尿路造影在小儿泌尿系梗阻诊断中的价值

目的 探讨磁共振尿路造影(MRU)技术在小儿泌尿系梗阻诊断中的价值. 方法 65例上尿路梗阻患儿行静脉肾盂造影(IVP)、B超及MRU检查,MRU检查应用快速自旋回波重T_2WI序列.对照MRU与手术结果,比较MRU与IVP、BUS在上尿路梗阻诊断中的价值. 结果 MRU诊断肾盂输尿管连接部狭窄36例,重复肾3例(其中误诊1例),原发性巨输尿管症9例,输尿管膀胱入口狭窄4例,输尿管末端囊肿3例,孤立肾2例,肾结石5例,神经性膀胱2例,先天性肾发育不良1例.MRU对上尿路梗阻的诊断正确率为98.5%(64/65),优于IVP及B超(P＜0.05). 结论 MRU是诊断小儿上尿路梗阻的可靠方法.     

磁共振尿路成像临床应用

目的 探讨磁共振尿路成像(MRU)的临床应用价值。方法 利用PHILIPS T5-NT 0.5T超导型MR扫描机,采用快速自旋回波(TSE)序列重T_2加权技术,对52例患者作MR尿路成像,行最大信号强度投影(MIP)处理,所有患者均先行常规MR扫描。结果 52例中,尿路梗阻扩张26例,其中:肾盂-输尿管交界段狭窄7例,输尿管癌4例,输尿管结石6例,输尿管炎性狭窄4例,输尿管外压1例,膀胱癌2例,神经源性膀胱2例。MRU显示尿路梗阻扩张正确率达100％,对梗阻定性诊断有3例错误。无尿路梗阻17例,其中肾癌3例,肾盂癌2例,肾血管平滑肌脂肪瘤1例,肾囊肿9例,马蹄肾1例,一侧肾缺如1例,均由MRI和MRU相结合确诊。另有9例患者呈现不同程度肾盂积水,未见尿路梗阻征象,其中:6例结合临床诊断为肾盂肾炎。52例中,部分病例与B超、IVU、CT扫描结果进行了比较。结论 MRU为一有效安全无创的影像检查技术,特别适用于肾功能不良和有IVU禁忌症者,对确定尿路梗阻扩张,梗阻的定位、定性有重要的应用价值。MRU和MRI相结合能对泌尿系统疾病的诊断提供更为完整的诊断依据。但在实践中,应依据患者具体情况合理选用MRU检查。     

排泄性三维对比增强尿路造影联合MR尿路造影在肾盂旁囊性病变诊断中的价值

目的 探讨排泄性三维对比增强磁共振尿路造影(3D-ceMRU)联合MR尿路造影(MRU)在肾盂旁囊性病变诊断中的价值.方法 对37例肾盂旁囊性病变患者行MRU及3D-ceMRU扫描,分析二者对肾盂旁囊性病变的显示情况,与临床最终诊断对照.结果 3D-ceMRU联合MRU扫描可满意显示肾盂旁囊性病变的部位、形态、大小、数量,对病变的定位诊断率达100％,定性诊断率达86％,并可粗略评价肾功能.结论 3D-ceMRU联合MRU能直观、清晰地显示肾盂旁囊性病变的部位、形态及与肾盂、肾盏关系,具有较高的定位、定性诊断准确性.     

尿路梗阻性病变的MRU应用

目的 探讨磁共振尿路造影(MRU)技术对尿路梗阻性病变的诊断价值。资料与方法 对46例经B超发现尿路扩张患者采用重T2WI单次激发快速自旋回波(SSFSE)序列行MRU检查，其中41例行静脉肾盂造影(IVP)。结果 46例尿路梗阻性病变包括：良性狭窄19例，先天性异常10例，输尿管结核5例，输尿管癌3例，外在性病变4例，输尿管结石4例，膀胱病变1例。MRU均清楚显示尿路影像，能确定有无梗阻，展示梗阻端的形态和特征，对梗阻水平的定位及梗阻原因的定性均有较高的准确性，明显优于IVP检查。结论 MRU是安全、有效的非侵袭性影像检查方法，特别适用于IVP禁忌症和肾功能丧失者。可多方位、多角度成像，结合常规T1WI、T2WI可获得可疑部位的大量信息，以达到明确诊断目的。     

MSCT曲面重组尿路成像与MRU对泌尿系病变的诊断比较

目的:比较MSCT曲面重组尿路成像(CTU)与磁共振尿路成像(MRU)在泌尿系病变检查中显示和诊断疾病的能力,探讨CTU、MRU对泌尿系病变的定位、定性诊断价值。方法:24例临床提示有泌尿系病变的患者,行MRI检查,采用单次激发快速自旋回波(SSFSE)序列,行MRU检查,同期采用10mm层厚层距,完成从肾上极至耻骨联合下缘CT平扫及增强扫描,获得原始横断面图像,将22例肾实质期和6例肾排泄期图像进行后处理,获得冠状面、矢状面及任意斜面尿路图像,在此基础上,再沿尿路走行方向管腔中心划曲线,进行曲面重组(CPR),获得CTU图像。采用盲法,比较CTU、MRU对泌尿系病变的定位、定性诊断价值。结果:CTU、MRU均对泌尿系梗阻病变部位作出明确诊断,定位诊断符合率为100%;CTU、MRU定性诊断符合率分别为100%和58.8%。对输尿管下段的显示CTU优于MRU,CTU能清楚地显示尿路全貌及其周围组织结构。结论:CTU、MRU对泌尿系梗阻病变均能明确定位;CTU定性诊断符合率明显高于MRU,能更直观显示泌尿系病变与扩张肾盂、输尿管的关系,在泌尿系病变诊断方面具有独特的优势。     

动态静脉尿路造影及MSCT尿路成像联合应用对泌尿系先天性畸形的诊断价值

目的:探讨动态静脉尿路造影(DIVU)及MSCT尿路成像(MSCTU)对泌尿系先天性畸形的诊断价值。方法:46例患者行DIVU检查,对尿路显影不良或需进一步明确诊断的12例再行MSCTU。结果:DIVU及DIVU后MSCTU联合诊断泌尿系先天性畸形46例,其中肾盂输尿管交界处狭窄12例,肾盂与输尿管重复畸形15例,输尿管囊肿7例,腔静脉后输尿管3例,肾融合畸形3例,肾发育不全2例,单侧肾缺如1例,异位肾1例,巨输尿管1例,膀胱憩室1例。结论:DIVU及MSCTU联合应用可明显提高先天性泌尿系畸形的显示率、诊断率。     

磁共振成像对输尿管梗阻诊断的价值

目的目的探讨磁共振成像(MRU)在输尿管梗阻性疾病诊断中的价值。方法对44例(其中输尿管肿瘤23例,输尿管结石8例,输尿管结核及炎性狭窄5例,输尿管息肉3例,巨输尿管症5例)输尿管梗阻病人进行了MRU检查,并与B超、CT、静脉尿路造影(IVU)、输尿管逆行造影结果进行比较。结果MRU能清楚显示输尿管梗阻的部位,对输尿管梗阻的定位诊断率为100%,定性诊断率为86%。结论MRU对输尿管梗阻的诊断率高,无创且不受肾功能影响,并发症少,是对输尿管梗阻病变的最佳显示方法。     

排泄性磁共振尿路造影对小儿尿路畸形的评估

目的:探讨应用利尿剂的排泄性磁共振尿路造影(EMRU)诊断小儿尿路先天畸形的应用价值.材料和方法:对24例已知或高度怀疑尿路先天畸形的儿童进行磁共振水成像尿路造影及增强后排泄性尿路造影(MRU),患者都使用了利尿剂.由2位经验丰富医师在不知病史的情况下分别对两种MRU成像方法的图像进行质量评估并做出对比分析.结果:60.4%的水成像与85.4%排泄性MRU图像质量达到了诊断要求;58.3%排泄性MRU与相应的成像MRU相比,其图像质量和观察效果得到了提高或改善;其中20例(20/24,83%)患者做出定位定性诊断,2例(2/24,8.3%)排除了相关异常.结论:利尿剂排泄性磁共振尿路造影(EMRU)能比较准确的显示泌尿路先天畸形,可以替代传统方法用于大部分怀疑有先天畸形的患儿.     

多时相MSCTU在上尿路先天性病变诊断中的价值

目的探讨多时相MSCTU在上尿路先天性病变诊断中的价值。方法收集2006年12月至2008年6月22例先天性上尿路发育异常病例,行平扫、动脉期、静脉期及低剂量分泌期扫描,各期图像减薄后传至工作站行MPR,CPR及CTU重建。结果22例中,2例马蹄肾,2例侏儒肾,1例异位肾,3例肾旋转不良,1例单肾合并肾盂输尿管移行部狭窄畸形,1例双肾盂旁囊肿,2例双肾盂双输尿管畸形,4例单肾盂旁囊肿,1例输尿管巨大憩室,1例下腔静脉后输尿管,3例肾盂输尿管移行部狭窄,1例侏儒肾且合并输尿管异位开口,所有病例均得到明确诊断。结论多时相MSCTU对上尿路先天性病变是最有价值的检查方法。     

MR urography: examination techniques and clinical applications

Modern MR urography is performed on the basis of two different imaging strategies, which can be used complementarily to cover almost all aspects in the diagnosis of upper urinary tract diseases. The first technique utilizes unenhanced, heavily T2-weighted pulse sequences to obtain static-fluid images of the urinary tract. T2-weighted MR urograms have proved to be excellent in the visualization of the markedly dilated urinary tract, even if the renal excretory function is quiescent. Static-fluid MR urography is less suitable for imaging of disorders that occur in the nondilated collecting system. The second MR urography technique is analogous to the methodology of conventional intravenous pyelography and is, therefore, designated as excretory MR urography. For this purpose, a non-nephrotoxic gadolinium chelate is intravenously administered and after its renal excretion, the gadolinium-enhanced urine is visualized using fast T1-weighted gradient-echo sequences. The combination of gadolinium and low-dose furosemide (5–10 mg) is the key for achieving a uniform distribution of the contrast material inside the entire urinary tract and, secondly, to avoid high endoluminal gadolinium concentrations, which cause signal loss of the urine due to T2^* effects. Gadolinium excretory MR urography allows to obtain high-quality images of both nondilated and obstructed urinary tracts in patients with normal or moderately impaired renal function. This article reviews the principles of T2- and T1-weighted MR urography in detail and informs how to use these techniques safely in potential clinical applications such as chronic urolithiasis, intrinsic and extrinsic tumor diseases, and congenital anomalies. Magnetic resonance urography performed in combination with standard MR imaging offers a potential to reduce the need for invasive retrograde pyelography. Although the economic aspect is still problematic, it is obvious that MR urography will continue to increase its role in clinical uroradiology. Received: 7 July 2000 Revised: 21 August 2000 Accepted: 21 August 2000     

MR virtual endoscopy of the upper urinary tract

OBJECTIVE: We investigated the feasibility of applying surface-rendered virtual endoscopy to the visualization of the upper urinary tract by processing unenhanced MR urography data sets. SUBJECTS AND METHODS: Twenty-six patients, having neoplastic lesions (n = 9), calculi (n = 8), pelviureteric junction stenoses (n = 4), postoperative fibrotic strictures (n = 3), and extrinsic compressions of the ureter (n = 2), underwent unenhanced MR urography. Virtual endoscopy of the upper urinary tract was obtained using a thresholding technique and surface-rendering MR urography data sets. RESULTS: Virtual endoscopy of the renal pelvis and calices was feasible in all cases on the side of the urinary obstruction. Virtual endoscopy of the ureter was obtained for a diameter of at least larger than 5 mm. The nondilated side could be partially explored in 11 cases (43%). The mean virtual endoscopy threshold required for the visualization of the urinary tract was 157.36-159.94. The mean time for virtual endoscopy was 13.8 min. Endoluminal masses were found in three (12%) of 26 cases on the renal pelvis (corresponding to neoplastic lesions), and occlusions, in 23 (88%) of 26 on the pelviureteric junction and ureter (neoplastic lesions and other abnormalities). CONCLUSION: Virtual endoscopy of MR urography data sets is feasible in patients with urinary tract dilatation. Virtual endoscopy displays the renal pelvis, calices, and ureter and, moreover, can show endoluminal changes caused by abnormalities.     

Diuretic-enhanced gadolinium excretory MR urography: comparison of conventional gradient-echo sequences and echo-planar imaging

The aim of this study was to investigate the utility of different gadolinium-enhanced T1-weighted gradient-echo techniques in excretory MR urography. In 74 urologic patients, excretory MR urography was performed using various T1-weighted gradient-echo (GRE) sequences after injection of gadolinium-DTPA and low-dose furosemide. The examinations included conventional GRE sequences and echo-planar imaging (GRE EPI), both obtained with 3D data sets and 2D projection images. Breath-hold acquisition was used primarily. In 20 of 74 examinations, we compared breath-hold imaging with respiratory gating. Breath-hold imaging was significantly superior to respiratory gating for the visualization of pelvicaliceal systems, but not for the ureters. Complete MR urograms were obtained within 14–20 s using 3D GRE EPI sequences and in 20–30 s with conventional 3D GRE sequences. Ghost artefacts caused by ureteral peristalsis often occurred with conventional 3D GRE imaging and were almost completely suppressed in EPI sequences (p < 0.0001). Susceptibility effects were more pronounced on GRE EPI MR urograms and calculi measured 0.8–21.7 % greater in diameter compared with conventional GRE sequences. Increased spatial resolution degraded the image quality only in GRE-EPI urograms. In projection MR urography, the entire pelvicaliceal system was imaged by acquisition of a fast single-slice sequence and the conventional 2D GRE technique provided superior morphological accuracy than 2D GRE EPI projection images (p < 0.0003). Fast 3D GRE EPI sequences improve the clinical practicability of excretory MR urography especially in old or critically ill patients unable to suspend breathing for more than 20 s. Conventional GRE sequences are superior to EPI in high-resolution detail MR urograms and in projection imaging. Received: 12 May 2000 Revised: 14 July 2000 Accepted: 17 July 2000     

Image quality, diagnostic certainty, and accuracy: comparison of conventional and digital urograms

Our previous research showed that radiologists could interpret digital urograms with sensitivity, specificity, and receiver operating characteristic (ROC) curve performance similar to their interpretations of conventional urograms. To evaluate further the suitability of digital radiology for performing excretory urography, we investigated relationships among image quality, radiologists' certainty of diagnostic decisions, and diagnostic accuracy for digital and conventional urograms. We examined data from a study of 100 excretory urograms performed using matched film-screen and digital exposures. Three radiologists rated the quality of digital urographic images compared to film-screen images. Image quality did not correlate well with diagnostic accuracy for either modality, perhaps because of the overall high level of quality of the exposures. Radiologists' level of certainty in their diagnostic decisions decreased with poorer image quality for both modalities. The similarities of the tested relationships provides further evidence that digital technology is suitable for use in urography.     

MR urography of obstructive uropathy: diagnostic value of the method in selected clinical groups

The aim of the study was to evaluate the role of MR urography (MRU) in the diagnosis of obstructive uropathy in selected groups of patients. The groups involved following pathologies: calculi; strictures of ureteropelvic junction (UPJ); benign and malignancy-induced ureterostenosis. Sixty patients with clinical diagnosis of obstructive uropathy were subjected to static fluid MRU (sMRU) with the use of 3D turbo spin echo (TSE) sequence in a 0.5-T magnet. The examination was completed with conventional MR sequences and in 12 cases additionally with sequences after the administration of Gd-DTPA and excretory MRU. The results were compared with intravenous urography (IVU), CT, US, clinical and histopathological data. The degree of the urinary tract dilatation as well as the level and type of obstruction were estimated. In patients with urolithiasis sMRU correctly depicted the degree of ureterohydronephrosis in 85%, in cases of UPJ stenosis and malignancy-induced ureterostenosis in 100% and in the group of benign ureterostenosis in 91% of patients. Determination of obstruction level in patients with stones was adequate in 92% and in cases of non-calculous ureteral strictures in 100% of patients. The sMRU sequence alone could not specify the nature of obstruction except 1 case of bladder carcinoma. Filling defects in ureters visible on MR urograms were verified with IVU or CT to exclude intrinsic tumours. Completed with conventional MR sequences sMRU enabled the depiction of solid mass or infiltration in 83% cases of malignancy-induced ureterostenosis, and in the remaining groups of patients neoplastic process was excluded in 91%. In conjunction with excretory MRU and conventional MR images sMRU appears to be a highly useful technique in assessment of obstructive uropathy, especially that of non-calculous origin. Among different clinical applications MRU is superior in the evaluation of dilated urinary tract in altered anatomical conditions (e.g. in patients with ileal neobladder). Electronic Publication     

Image quality,diagnostic certainty,and accuracy: Comparison of conventional and digital urograms

Our previous research showed that radiologists could interpret digital urograms with sensitivity, specificity, and receiver operating characteristic (ROC) curve performance similar to their interpretations of conventional urograms. To evaluate further the suitability of digital radiology for performing excretory urography, we investigated relationships among image quality, radiologists’ certainty of diagnostic decisions, and diagnostic accuracy for digital and conventional urograms. We examined data from a study of 100 excretory urograms performed using matched film-screen and digital exposures. Three radiologists rated the quality of digital urographic images compared to film-screen images. Image quality did not correlate well with diagnostic accuracy for either modality, perhaps because of the overall high level of quality of the exposures. Radiologists’ level of certainty in their diagnostic decisions decreased with poorer image quality for both modalities. The similarities of the tested relationships provides further evidence that digital technology is suitable for use in urography.     

Visualization of urinary tract dilatation: value of single-shot MR urography

The purpose of this study was to evaluate detection of urinary tract dilatation, depiction of obstruction level and determination of cause with single-shot MR imaging in an acquisition time of 2.8 s. Heavily T2-weighted single-shot MR images in 50 patients with ureterohydronephrosis as suspected by ultrasound were prospectively compared with IV urography and clinical outcome. Imaging techniques were obtained within a maximum time interval of 4 h and assessed independently on the same day. Single-shot MR urography was able to demonstrate dilatation and obstruction levels in 96 % of urinary tracts in accordance with X-ray urograms. In 4 patients with a unilaterally negative IV urogram, obstruction levels were demonstrated in single-shot MR urography. Single-shot MR urography did not depict 2 of 7 collecting systems with mild dilatation and contralateral undilated ureters were not adequately visible. Single-shot MR urography consistently visualizes dilated urinary tracts and obstruction levels in moderate and severe dilatation. Single-shot MR urography may be an alternative for IV urography in cases of renal impairment, when iodinated contrast or the application of X-rays is contraindicated, and may help in avoiding direct ureteropyelography. Single-shot MR urography rarely allows determination of the cause of urinary tract dilatation. Received 19 July 1996; Revision received 4 November 1996; Accepted 5 February 1997     

原发性输尿管癌的诊断:传统尿路造影术与CT、MRI比较(附15例分析)

目的：评价传统尿路造影、ＣＴ与ＭＲＩ在原发性输尿管癌诊断中的价值。材料和方法：本１５年（１６个部位）经手术和病理证实的病例中，１３例（１４次）行静脉肾孟造影（ＩＰＶ），６例（７例）逆行肾盂造影；１例肾穿刺造影；６例ＣＴ检查，其中４例加增强扫描；２例ＭＲＩ检查，先以自旋回波（ＳＥ）序列做轴有冠状面Ｔ１和Ｔ２加仅扫描，再做冠状面磁共振尿路选影（ＭＲＵ）．结果：传统尿路造影共８例９次（６４％）获得术前