State of the art trends in imaging renal of colic

Radiology has a primary role in the work-up of renal colic, both to confirm urolithiasis and to help determine management. The traditional imaging has been conventional radiography and intravenous urogram with multidetector non-contrast-enhanced helical computed tomography (NCECT) now the modality of choice. Nuclear medicine studies for renal colic are done now infrequently at most institutions. Ultrasound (US) is often done, especially in the emergency department, and magnetic resonance imaging (MRI) is promising. Radiation dose reduction is now on everyone’s minds: Lower-dose CT techniques are being tested and used, and US and MR are considered as first modalities of choice in pregnant women and children.     

Non-contrast spiral CT for patients with suspected renal colic

Renal colic, defined as acute flank pain caused by the passage of a ureteral calculus, is a common condition, but the correct diagnosis may not be apparent clinically. For decades, intravenous urography has been the test of choice for evaluating patients with suspected renal colic. Recently, unenhanced (non-contrast) helical CT has been shown to be an accurate and highly effective examination which can be used instead of intravenous urography. In this article, the technique is reviewed in detail, including its advantages and potential pitfalls.     

Evaluation of image quality and dose in renal colic: comparison of different spiral-CT protocols

The aim of this study was to test different technical spiral-CT parameters to obtain optimal image quality with reduced X-ray dose. Images were acquired with a spiral-CT system Philips Tomoscan AVE1, using 250 mA, 120 kV, and 1-s rotational time. Three protocols were tested: protocol A with 5-mm thickness, pitch 1.6, slice reconstruction every 2.5 mm; protocol B with 3-mm thickness, pitch 1.6, slice reconstruction every 1.5 mm; and protocol C with 3-mm thickness, pitch 2, slice reconstruction every 1.5 mm. Two phantoms were employed to evaluate the image quality. Axial images were acquired, then sagittal and coronal images were reconstructed. Finally, the absorbed X-ray dose for each protocol was measured. Regarding image quality, 5-mm-thick images (protocol A) showed greater spatial resolution and lower noise compared with 3-mm-thick images (protocols B and C) on the axial plane; 3-mm reconstructed sagittal and coronal images (protocols B and C) showed an improved image quality compared with 5-mm reformatted images (protocol A). Concerning X-ray dose, the mean dose was: protocol A 19.6 +/- 0.8 mGy; protocol B 14.4 +/- 0.6 mGy; protocol C 12.5 +/- 1.0 mGy. Our study supports the use of thin slices (3 mm) combined with pitch of 1.6 or 2 in renal colic for X-ray dose reduction to the patient and good image quality.     

CT KUB scans for renal colic: Optimisation of scan range to reduce patient radiation burden

IntroductionNon-contrast CT KUB scans performed to assess renal colic should be limited to scanning between the upper pole of the highest kidney and the pubic symphysis to minimise unnecessary irradiation. This audit aimed to assess the amount of overscanning in CT KUBs outside this range.MethodsCT KUB scans taken over a 10-day period were assessed. Unnecessary overscan above the highest kidney was measured as a percentage of the total scan range. A target of less than 10% overscanning was set. The vertebral position of the upper pole of the highest kidney was also measured and compared to the actual level of the scan.Results88 patients were assessed. 89.8% (79/88) of scans didn't meet the target of less than 10% overscanning above the highest kidney, and were associated with a higher radiation dose to the patient. The average overscanning above the highest pole of the kidney was 16.4% of the whole scan. The average overscan below the pubic symphysis was 1.54%. We also found that 100% of scanned kidneys lied below the upper border of the T11 vertebra, in spite of scans starting as high as T7.ConclusionA large proportion of scans included unnecessary overscanning above the highest kidney. We have identified the upper border of the T11 vertebral body as a potential location from which to begin the upper margin of a CT KUB scan.Implications for practiceBy starting CT KUB scans at the upper border of the T11 vertebral body, we can allow the whole kidney to be imaged while minimising unnecessary overscanning above the kidney, thus lowering excess patient irradiation while still producing high quality scans.     

Acute flank pain: comparison of unenhanced helical CT and ultrasonography in detecting causes other than ureterolithiasis

Several conditions can clinically mimic renal colic. We assessed the accuracy of non-contrast-enhanced helical CT and of ultrasonography (US) in offering an alternative explanation for flank pain. In a 3-year period, 181 patients with acute flank pain underwent US and non-contrast-enhanced helical CT in a blinded sequence. Their efficacy in detecting both alternative causes of pain and additional findings unrelated to the pain was assessed in 160 cases with a confirmed diagnosis. An alternative cause was found in 23 cases (14%). US gave 4 false-negative results (1 acute appendicitis, 1 ovarian cyst torsion, 1 diverticulitis, and 1 papillary necrosis) and 2 false-positive results (1 acute pyelonephritis and 1 diverticulitis), with a 78% sensitivity and a 98% specificity for nonlithiasic causes. CT gave 5 false-negative results (1 complicated ovarian cyst, 1 pleuritis, 1 epididymitis, 1 acute pyelonephritis, and 1 papillary necrosis) and 1 false-positive (1 simple ovarian cyst described as a complicated lesion), resulting in a 74% sensitivity and a 99% specificity for diagnosing alternative causes. There were 130 additional US findings in 68 patients and 151 additional CT findings in 77 patients. A wide spectrum of findings can be identified in subjects imaged for flank pain. Non-contrast-enhanced helical CT and US have comparable accuracy in diagnosing causes other than stone disease. Electronic Publication     

Combined magnetic resonance urography and targeted helical CT in patients with renal colic: a new approach to reduce delivered dose

PURPOSE: To determine whether magnetic resonance urography (MRU), obtained before helical computed tomography (CT) in patients with acute renal colic, can help delimit the obstructed area to be subsequently examined by a targeted CT scan, thus reducing the dose of radiation. MATERIALS AND METHODS: Patients (51) with symptoms of acute renal colic underwent MRU and a total urinary tract helical CT. CT images from the 5 cm below the level of ureteral obstruction as demonstrated by MRU were selected out. Combined interpretation of MRU and selected CT images constituted protocol A. Protocol B consisted of the entire unenhanced helical CT of the urinary tract. The two protocols were compared regarding the following points: 1) sensitivity in diagnosing the presence of obstructing urinary stones, and 2) the delivered radiation dose. RESULTS: Protocol A and protocol B had, respectively, 98% and 100% sensitivity in demonstrating ureteral stone as a cause of renal colic. Estimated average dose calculated from phantom study was 0.52 mSv for protocol A and 2.83 mSv for protocol B. Therefore, the effective radiation dose was 5.4 times lower in protocol A compared to protocol B. CONCLUSION: Combined MRU and short helical CT has a high sensitivity in detecting ureteral calculi with a reduced radiation dose.     

放射性核素肾动态显像与静脉肾盂造影评价肾功能的比较

肾脏疾病患者进行放射性核素肾动态显像(RDI)及静脉肾盂造影(IVP)对判断分肾功能具有重要的临床意义.IVP是泌尿系统检查中的常用传统检查方法,但由于此检查在肾功能不全时可致患肾显影不清或不显影,从而低估患肾功能.而RDI具有简便、无创伤、灵敏度高、可重复、可定量评价肾功能的特点,是较IVP更为理想的评价肾功能的方法.IVP患肾不显影时,应进一步行99Tcm-二乙烯三胺五乙酸RDI.     

Assessment of accuracy of renal artery stenosis grading in helical CT angiography using maximum intensity projections

The purpose of the study was to investigate whether visual inspection of maximum intensity projection (MIP) images is a reliable method for assessment of the severity of renal artery stenoses (RAS). Therefore, 20 RAS were investigated with helical CT. Native axial images and MIP images were analysed separately or in combination (two-step method). A phanton study was performed to investigate the influence of window setting on apparent stenosis severity. Accuracy for diagnosis of 50–69% and 70–99% RAS and the mean inter-observer agreement were 82.5%, 77.5% and 82.5% respectively, using study of MIP images alone, and 100%, 97.5% and 95% using the two-step method. The phantom study showed that the apparent severity of vascular stenoses on MIP images depends on the selected window centre values. It is concluded that combined evaluation of both MIP images and native axial images is more reliable than study of MIP images alone for assessing the severity of RAS. Correspondence to: L. Van Hoe     

Spontaneous renal artery dissection revealed by helical CT angiography

Spontaneous renal artery dissection is rare and may be misdiagnosed because its clinical presentation is confusing. Diagnosis is usually made by intra-arterial angiography. We report a case where a spontaneous renal artery dissection was initially misdiagnosed as a renal abscess. Diagnosis was made later with helical CT for suspicion of renal artery stenosis in a patient with recent onset of hypertension. This unusual case shows that helical CT can be useful for non-invasive diagnosis of renal artery dissection. Received: 20 May 1999; Revised: 2 September 1999; Accepted: 3 September 1999     

Dual modality imaging of positron emission tomography-computed tomography (PET-CT) in evaluation of postoperative renal cancer patients

Objective

The aim of our study was to determine the role of PET-CT in detection of recurrence and metastasis of renal cell carcinoma.

超声检查和X线尿路造影对输尿管狭窄诊断的临床研究（附98例分析）

目的：评价超声检查和X线尿路造影在输尿管狭窄中的诊断价值,帮助临床医生合理地选择检查方法。方法：本组98例输尿管狭窄的患者均作了超声及静脉尿路造影检查,36例作了逆行尿路造影。结果：超声、静脉尿路造影、逆行尿路造影对输尿管狭窄定位诊断的总符合率分别为66．3％、86．7％和94．4％。不同检查方法对不同部位诊断的符合率不同,对肾盂输尿管移行区,输尿管末端,肾盂输尿管移行区－输尿管末端之间诊断符合率超声分别为83．3％、75％和33．3％,静脉尿路造影分别为79．2％、95％和93．3％,逆行尿路造影分别为95％、75％和100％。输尿管狭窄病因的诊断符合率超声为42．9％,静脉尿路造影为78．6％,逆行尿路造影94．4％。结论：尿路造影是诊断输尿管狭窄的可靠方法,超声因经济、简便可作为一种首选的检查手段。     

肾动脉狭窄的肾脏CT血流灌注参数研究

目的:探讨利用CT血流灌注参数研究肾动脉狭窄患者肾脏血流状况。方法:高血压患者36人,分为肾动脉狭窄组(24人)和对照组(12人),进行肾脏CT电影扫描获得动态序列图像,通过AW影像工作站计算肾脏皮质血流灌注参数,分析肾脏皮质血流灌注与肾动脉狭窄的关系。结果:肾动脉狭窄>75%组肾皮质单位体积血流量(BF)(189.9±102.3ml/100g/min)低于对照组(308.4±99.9ml/100g/min),有显著差异(P=0.026)。肾动脉狭窄50%-75%组及狭窄>75%组肾皮质微血管容积(BV)(24.6±7.6ml/100g,21.4±12.6ml/100g)低于对照组(41.1±14.1ml/100g),有非常显著差异(P=0.008,0.001)。各组之间平均通过时间(MTT)、毛细血管表面通透性(PS)无显著性差异(P>0.05)。结论:明显肾动脉狭窄的肾脏皮质BF、BV下降,CT血流灌注参数可以为评估肾动脉狭窄的肾脏是否缺血提供帮助。     

超声检查诊断肾癌的临床应用价值(附60例分析)

目的:评价超声检查肾癌的表现及声像图特征,提高超声检查对肾癌的诊断水平。方法:对60例经手术和病理证实的肾癌术前超声诊断和临床资料进行对比分析。结果:肾癌超声检查的声像图表现为多样性,60例中以不均质中低回声病灶最多见,共42例,占70%;混合性回声病灶12例,占20%;囊性病灶6例,占10%。超声诊断符合率95%。结论:超声检查对肾癌具有较高的诊断价值,超声科医生应对肾癌声像图全面掌握,以提高对肾癌术前诊断正确率,减少误诊率的发生。     

Power Doppler imaging in acute renal vein occlusion and recanalization: a canine model.

OBJECTIVE: To evaluate the dynamic changes of the power Doppler (PD) in acute renal vein occlusion and recanalization in a canine model. MATERIALS AND METHODS: We performed a PD of the kidney during graded renal vein occlusion and recanalization induced by balloon inflation and deflation in nine dogs. The PD images were transferred to a personal computer, and the PD signals were quantified. RESULTS: We observed the temporal change of the PD signal during renal vein occlusion and recanalization, with a decrease in the PD signal during occlusion and an increase during recanalization. The mean PD signal decreased gradually as the renal vein was occluded, and conversely increased gradually with sequential relief of occlusion. The sequential change of the mean value of the PD signal was statistically significant. CONCLUSION: The PD can detect a change in renal blood flow during acute renal vein occlusion and recanalization in a canine model. The PD may be used as a helpful tool for the early detection of acute renal vein thrombosis and the monitoring of renal perfusion.     

肾脏及其恶性肿瘤的CT灌注成像研究

肾脏恶性肿瘤的发病率近年来有逐渐上升的趋势,早期诊断对其治疗及预后有重要意义。随着MSCT的不断发展及应用,CT灌注成像技术在肾脏及其恶性肿瘤方面的应用成为研究的热点与难点,本文综述了CT灌注成像技术在肾脏及其恶性肿瘤方面的应用现状及优缺点,对其诊断及鉴别诊断有一定指导意义。     

螺旋CT泌尿系统重建成像在血尿诊断上的临床应用

目的:对螺旋CT泌尿系统重建成像在泌尿系统疾病特别是血尿原因检查方面的临床价值做进一步探讨。材料和方法:对152例病人进行螺旋CT泌尿系统成像(血尿患者138例),其中非增强螺旋CT肾输尿管成像72例,排泄性CT泌尿系造影80例重建成像进行分析,包括:①结合临床检查结果确定诊断;②对照轴扫图像和影像检查资料主要是IVP,对重建成像效果和临床价值进行评价。结果:非增强肾输尿管成像72例中,发现输尿管结石45例(3例合并肾结石),膀胱结石7例;膀胱癌(1例合并肾盂癌)9例,腹膜后病变导致输尿管狭窄9例;未见明确异常7例。80例SCTU中,肾实质肿瘤侵犯肾盂22例,肾盂癌5例,慢性肾盂肾炎2例,输尿管病变18例,后腹膜及盆腔肿瘤压迫输尿管7例,膀胱肿瘤7例,先天畸形5例,结核2例,肾脓肿3例,未见明确异常4例。SCTU与IVP对照,两者对泌尿系解剖部位的显示(肾盂,输尿管,膀胱)大致相当。所有IVP所提示的病变,SCTU均能发现。11例IVP不能确定者于SCTU明确诊断。结论:螺旋CT泌尿系统重建成像技术具有较高的临床应用价值,有望取代IVP成为血尿原因检查的首选方法。     

Multidetector CT Urography in Imaging of the Urinary Tract in Patients with Hematuria

This review article comprehensively discusses multidetector CT urography protocols and their role in imaging of the urinary tract in patients with hematuria.     

Primary renal and retroperitoneal actinomycosis

A case of the rare condition of renal and retroperitoneal actinomycosis is presented. The clinical and imaging (ultrasonography and computed tomography) findings are described and attention is drawn to the diagnostic difficulties in this rare disease. Received: 26 October 1998; Revised: 5 February 1999; Accepted: 7 May 1999