低剂量对比剂CTU的可行性研究

目的探讨采用低剂量对比剂64排螺旋CT尿路造影(CTU)显示尿路结构的可行性。资料与方法将60例临床拟诊泌尿系病变患者分成3个使用不同剂量对比剂组(2.0 ml/kg体重、1.5 ml/kg体重、1.0 ml/kg体重),每组20例,然后行64排螺旋CTU检查与图像后处理,获得三维容积再现(VR)、最大密度投影(MIP)和二维曲面重组(CPR)图像,并对图像中尿路解剖结构与连续性状况的显示效果和尿路的充盈程度进行对比分析。结果不同对比剂剂量组间CTU解剖结构显示效果的差异无统计学意义,不同对比剂剂量组间CTU图像尿路连续性评分差异无统计学意义,不同对比剂剂量组间排泄期输尿管测量的最大管径值差异无明显统计学意义(P值均>0.05)。结论采用低剂量对比剂64排螺旋CTU显示尿路结构具有可行性。     

多层螺旋CT在评价血尿原因中的应用价值

目的 探讨多排螺旋CT尿路造影(MDCTU)在评价血尿原因中的应用价值.资料与方法 对48例血尿患者行MDCTU检查和图像三维重组,重组方式包括容积再现(VR)、最大密度投影(MIP)、多平面重组(MPR)和曲面重组(CPR),并对其重组图像进行综合评估.然后将尿路系统分为梗阻组和非梗阻组,分别对其重组图像中的尿路解剖结构和尿路连贯性的显示效果进行对比分析.结果 VR与MIP图像的显示效果依赖于管腔内对比剂充盈情况,MPR及CPR图像不依赖于管腔内对比剂充盈情况,两组间CPR对尿路连贯性的显示效果以及对尿路解剖结构的显示效果差异均无统计学意义,CPR的应用弥补了VR和MIP的不足,使整体观察效果得到了明显提高并有助于诊断.MDCTU的诊断准确率为97.8%(44/45).结论 MDCTU的图像质量好,对血尿原因的综合评价能力较强,在泌尿系统疾病检查中具有较好的应用价值和推广价值,当尿路有梗阻、肾功能差或输尿管收缩时,CPR有助于影像学诊断.     

256层CTU尿路造影对输尿管梗阻性病变的诊断价值

目的 探讨多层螺旋CT尿路造影(CTU)在诊断输尿管梗阻性病变中的临床价值.方法 收集本院2011年5月～2012年6月的输尿管梗阻性病变30例,均行腹盆腔多层螺旋CT容积扫描,1 mm薄层重建图像传输至Vitrea2工作站,对所获得图像进行容积再现(VR)、最大密度投影(MIP)、多平面重建(MPR)、曲面重建(CPR)等方式后处理.结果 本组术前CTU诊断正确28例,另2例术前怀疑输尿管肿瘤,后经手术病理证实为输尿管结核,CTU的诊断准确率为93%(28/30).CTU成功率100%,图像清晰,诊断准确率高.结论 CTU通过VR、MIP、MPR、CPR后处理,能清晰显示输尿管扩张的整体形态,明确梗阻部位、病变性质、病灶与周围组织的解剖关系,对输尿管梗阻病变的诊断有很高的临床应用价值.     

基于不同扫描方案下MSCT尿路成像图像质量研究

目的 探讨四种不同扫描方案下64层螺旋CT尿路成像技术的图像质量,寻求最佳的尿路显影方法.方法 60名泌尿系统正常人群分为4组,每组15名,分别采用以下辅助方法进行5分钟延迟扫描:A组,大量饮水仰卧位;B组,大量饮水俯卧位;C组,静脉水化;D组,少量利尿剂,对尿路连续性解剖结构、输尿管充盈度的显示进行图像质量对照评估.结果 A组和B组对于整个泌尿系统评价无明显差异,C组在尿路解剖结构的显示和尿路连续性评分方面与A、B组无明显差异,但是输尿管充盈程度明显高于A组(P=0.010)和B组(P=0.008).D组的图像质量在尿路连续性评分和输尿管充盈度上明显高于其他3组,其平均输尿管内径显示最饱满,平均直径为(7.04±2.06)mm.结论 少量利尿剂的使用能够显著增加泌尿系统全程显影,对泌尿系统的总体显示效果最好,值得临床推广应用.     

尿路病变CT尿路造影的临床应用

目的：探讨CT尿路造影（CTU）在尿路病变中的临床诊断价值。材料和方法：对34例经临床和病理证实的尿路病变患者的CTU影像资料进行回顾性分析；所有患者采用16层CT进行平扫、增强及CTU（排泄期成像）检查，并将图像进行最大密度投影重建（MIP）、曲面重建（CPR）和三维容积重建（VR）。将各种重建方法所得图像诊断价值分为三级：0级：不能进行定位定性分析；l级：可定位分析但不能定性分析；2级：能进行定位定性分析。比较各种重建方法的临床诊断价值，比较CT平扫、增强及CTU图像对各类尿路疾病的诊断价值。结果：曲面重建和MIP重建方法在CTU成像中具有较高的定位定性诊断价值，平扫、增强及CTU图像对不同类型的尿路疾病诊断价值不同。结论：对于尿路病变CTU检查具有较高的临床应用价值，不同类型的尿路病变应合理地选用CTU。     

低剂量CT尿路造影的临床应用

目的 探讨低辐射剂量CT尿路造影(CT urography,CTU)的临床应用价值.方法 收集有泌尿系临床症状患者95例,分别行低辐射剂量和常规剂量排泄期多层螺旋CT尿路造影技术检查.低剂量组70例,采用120 kV,电流值分别分为100 mA、75 mA、50 mA 3组,常规剂量组25例,采用120 kV,220 mA进行扫描.所有数据传输到后处理工作站进行MPR、CPR、VR及MIP等三维重建.结果 低剂量3组与常规剂量组之间辐射剂量相比分别降低57%、68%、79%,差异有统计学意义(t值分别为20.43、27.73、26.79,P<0.05).常规剂量组25例肾盂CT值(773.1±141.6)HU,低剂量组70例肾盂CT值(761.2±129.8)HU,两者之间无显著性差异(t值为0.382,P>0.05).常规剂量组25例肾盂CT值的标准差为(23.2±5.3)HU,低剂量组肾盂CT值的标准差为(60.1±15.9)HU,两者之间有显著性差(t值为-50.19,P<0.05).常规剂量CTU对泌尿系统结构的显示效果略优于低剂量CTU组,低剂量CTU(100 mA)组、(75 mA)组与常规组无显著性差异(χ2值分别为0.006、0.162,P>0.05),50 mA组与常规组有显著性差异(χ2值为9.224,P<0.05).结论 低辐射剂量排泄期CTU降低了辐射剂量,对泌尿系统的总体显示效果能够满足影像学诊断的要求,具有较好的临床应用价值.     

多层螺旋CT四步观察法在肋骨微细骨折中的应用

目的 探讨CT图像不同后处理技术的组合方式在肋骨微细骨折诊断中的价值.方法对98例多层螺旋CT (multislice spiral CT,MSCT)检查显示细微骨折的患者进行观察.分别用(A)容积再现(volume rendering, VR)+曲面重组(curved planar reformation, CPR)+轴位;(B)最大强度投影(maximum intensity projection, MIP)+CPR+轴位及(C)VR+MIP+CPR+轴位3种不同图像组合方式观察.结果 98例患者,显示肋骨细微骨折265处.采用VR+MIP+CPR+轴位(四步观察法)的C组资料,肋骨微细骨折的检出率分别高于A组( χ~2＝6.67,P＜0.01)和B组(χ~2＝6.75,P＜0.01). 结论 MSCT"四步观察法"能提高肋骨微细骨折的检出率,有较高的临床价值.     

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。     

64层容积CT尿路造影对泌尿系统先天畸形的诊断价值

目的 探讨64层容积CT尿路造影(VCTU)对泌尿系统先天畸形的诊断价值.资料与方法 66例经手术、输尿管镜或临床证实的泌尿系统先天畸形患者行VCTU检查,并行容积再现(VR)、最大密度投影(MIP)、多平面重组(MPR)及曲面重组(CPR)后处理,获得尿路重建图像.结果 66例患者中(2例为多发畸形),肾盂输尿管重复畸形32例,马蹄肾7例,肾旋转不良6例,肾盏憩室5例,先天性肾盂输尿管连接处狭窄5例,先天性巨输尿管1例,输尿管开口异位1例,腔静脉后输尿管1例,输尿管囊肿3例,膀胱憩室7例.VCTU图像清晰、立体感强,可多角度观察尿路,诊断正确率达100％.结论 VCTU通过VR、MIP、MPR、CPR图像能准确显示泌尿系统先天畸形及其伴发病变,提高了病变检出率和诊断正确率,可作为诊断泌尿系统先天畸形的首选方法.     

自发性孤立性肠系膜上动脉夹层的MSCTA诊断

目的:探讨多层螺旋CT血管造影(MSCTA)及其后处理技术在自发性孤立性肠系膜上动脉夹层(SISMAD)诊断方面的价值.方法:回顾分析11例经DSA证实和(或)有典型CT表现的SISMAD患者资料,所有病例均行MSCTA检查.采用Yun分型.依据CTA,结合容积再现(VR)、多平面重组(MPR)、曲面重组(CPR)及最大密度投影(MIP)后处理图像,分析SISMAD影像特征,并分别计算各种方法对初始破口、内膜瓣和真假腔的显示率.结果:11例中Yun Ⅰ型1例,Ⅱb型8例,Ⅲ型2例.CTA清晰显示撕裂内膜11例,内膜破口均位于肠系膜上动脉(SMA)近心端,夹层累及SMA主干及分支.MPR与CPR对初始破口、内膜瓣和真假腔的显示率分别为90.9％、100％、100％,VR与MIP对初始破口的显示率分别为54.5％和27.3％,而对内膜瓣与真假腔的显示率均为45.5％.结论:MSCTA及其后处理技术能清晰显示SISMAD病变特征和累及范围,MPR及CPR对破口显示率优于MIP,而对内膜瓣及真假腔显示率优于MIP及VR.     

Diuretic radionuclide urography

Diuretic radionuclide urography is a modification of conventional renography which utilizes the administration of intravenous furosemide to distinguish dilated, non-obstructed, hydronephrotic systems from those with significant mechanical obstruction. Diagnostic patterns are derived from computer generated time-activity histograms that depict the accumulation and washout of radiotracer before and after diuretic injection. In dilated but non-obstructed systems, diuresis produces a decline in activity. In obstructed systems, there is a failure of radiotracer washout in response to diuresis and no decline in activity is observed. The procedure is applicable to patients of all ages with suspected upper urinary tract obstruction. Clinical and experimental data support the accuracy and utility of this methodology and define its limitations and pitfalls.     

Diuretic therapy and exercise performance

Drugs that induce an increased urine flow are used both legitimately (treatment of hypertension and oedema) and otherwise (rapid weight loss) in sports and exercise. There are 5 major categories of diuretic drugs based on their mechanisms and loci of action. Common to all classes is hypohydration, which has been shown to have an array of adverse effects on performance, including impaired strength, power and endurance. Postural hypotension can be particularly troublesome in the elderly. Also common to all diuretics, except those interfering with the aldosterone mechanism in the distal nephron, is hypokalaemia. Severe symptomatic hypokalaemia (serum K+ concentration less than 3.0 mmol/L) is rare except in clinical situations in which additional hypokalaemic factors are present. Moderate levels of hypokalaemia (serum K+ concentration 3.0 to 3.5 mmol/L) can increase the risk of adverse reactions as has been shown in a variety of prospective clinical studies. Hypokalaemia has effects on cardiac rhythm, muscle function and integrity, local blood flow, carbohydrate metabolism, and the blood lipid profile. Performance studies generally show diminished exercise tolerance in direct proportion to the degree of hypohydration induced. This is not the case, however, in a clinical setting of compromised cardiopulmonary function, in which diuresis has direct and indirect inotropic effects which augment exercise tolerance and decrease symptoms. The ability of the carbonic anhydrase inhibitor, acetazolamide, to induce a hyperventilatory response to the obligatory metabolic acidosis is taken advantage of in mountaineering to prevent or ameliorate the symptoms of acute mountain sickness, thereby improving exercise performance at high altitude. It is suggested that in clinical situations in which the use of a diuretic is considered appropriate, every effort be made to maintain or restore the serum concentration and the total body store of potassium to normal. To some degree this can be accomplished through diet, although potassium chloride supplements or potassium-sparing diuretics or diuretic combinations may be necessary.     

Diuretic renography: Concepts and controversies

Diuretic renography has proved to be a reliable, noninvasive test for the diagnosis of upper urinary tract obstruction. False positive and false negative results may occur but can be minimized by careful attention to technique. The timing of diuretic administration, state of hydration, and furosemide dosage appear to be the key methodologic variables.     

Diuretic renography: concepts and controversies.

Diuretic renography has proved to be a reliable, noninvasive test for the diagnosis of upper urinary tract obstruction. False positive and false negative results may occur but can be minimized by careful attention to technique. The timing of diuretic administration, state of hydration, and furosemide dosage appear to be the key methodologic variables.     

Diuretic renography and angiotensin converting enzyme inhibitor renography

Renovascular hypertension and renal outlet obstruction are two clinical conditions well evaluated by nuclear medicine techniques. They both require a specific intervention to challenge a specific aspect of renal functional reserve. Diuretic renography is the oldest common example in nuclear medicine where functional change in the kidney is provoked for diagnostic purposes. The kidney's tubular functional reserve, in this instance, is challenged to induce diuresis and increase urine flow. This intervention permits diuretic renography to retain an essential role in the evaluation of hydroureteronephrosis. Captopril renography is a more recent example of a similar principle and depends on a reactive renin-angiotensin system to identify a kidney responsible for RVH. In both renal outlet obstruction and RVH, an anatomic abnormality is also identified (hydronephrosis and RAS, respectively) at some point in the diagnostic workup. The final diagnosis in each instance, however, depends on evidence for a functional disorder, provoked and measured during the radionuclide interventional examination. These serve as excellent examples of the power of functional imaging to identify specific medical disorders.