Common bile duct stones: reassessment of criteria for CT diagnosis

To evaluate the specificity of previously suggested computed tomographic (CT) criteria for diagnosing common bile duct (CBD) stones, CT scans of 38 patients with CBD stones were compared with scans of 32 patients with carcinoma obstructing the CBD and 28 nonobstructed patients. The CBD stone was directly visualized as a target sign or densely calcified structure in 29 of 38 patients with stones (76%); one with carcinoma showed a similar target sign. A rim of increased density in the distal CBD was found without accompanying target sign in six patients with stones (16%), compared with 12 with carcinoma (38%) and 15 nonobstructed patients (54%). Irregular intraluminal densities without a detectable target sign were noted in four patients with stones (11%), compared with eight with carcinoma (25%) and nine nonobstructed patients (32%). Abrupt termination of the CBD without a mass was more common as an isolated finding in patients with carcinoma (31%) than in patients with stones (13%). CT is accurate in detecting CBD stones in certain patient populations, but direct visualization of the stone is required.     

Bullet colic

Ureteral obstruction by intramural bullet, buckshot, or related missle following penetrating abdominal trauma is rare; a search of the literature revealed only 4 previously described cases [1-4]. A fifth case of a bullet migrating from the renal pelvis to the ureter has been reported at autopsy [5]. We present 2 new cases of delayed symptomatic ureteral obstruction ("bullet colic") after abdominal gunshot wounds.     

Rupture of renal artery aneurysm into the renal pelvis, clinically mimicking renal colic: diagnosis with multidetector CT

We report on a 60-year-old man, seen at the emergency department because of severe left flank pain. Clinical diagnosis was that of renal colic. Overnight he became haemodynamically unstable and haematuria became massive, so multidetector CT (MDCT) was performed. MDCT with reconstructions can represent complex imaging findings in a more straightforward way compared with transverse images. Rupture of a renal artery aneurysm into the left pelvis was seen on coronal reconstructed CT images. Nephrectomy was performed. Rupture of a renal artery aneurysm into the pelvis is unusual and death is likely if diagnosis and treatment are delayed. The initial clinical presentation may be very similar to renal colic. MDCT allows timely and correct diagnosis of this unusual condition.     

Dynamic contrast-enhanced MR urography in the evaluation of pediatric hydronephrosis: Part 2, anatomic and functional assessment of uteropelvic junction obstruction

OBJECTIVE: The purpose of our study was to retrospectively review our experience using MR urography in the diagnosis of ureteropelvic junction (UPJ) obstruction in children. MATERIALS AND METHODS: Sixty-one studies were performed in 50 children with hydronephrosis but without hydroureter. Anatomic criteria assessed included degree of hydronephrosis, morphology of the renal pelvis, atrophy of medulla, swirling contrast material, fluid levels, and the presence of fetal folds and crossing vessels. Functional criteria included renal transit time, differential renal function, and time-intensity curves when available. RESULTS: Thirty-one kidneys were classified as obstructed, 15 as equivocal, and 15 as nonobstructed. Obstructed systems had more marked hydronephrosis, more extensive medullary atrophy, more fluid levels, and more swirling contrast material. Fetal folds were seen in only the equivocal and nonobstructed groups. Crossing vessels were seen in all groups. Obstructed systems also showed greater functional derangement, decreased split renal function, and abnormal time-intensity curves. CONCLUSION: MR urography provides both excellent anatomic and functional information in children with UPJ obstruction in a single test that does not use ionizing radiation. MR urography may lead to greater understanding of the pathophysiology of UPJ obstruction.     

Obstructive migration of renal calculi following cyst aspiration

The authors report 3 cases of ureteral obstruction secondary to puncture of peri-pelvic renal cysts which had been obstructing and dilating the renal pelvis. In each case, non-obstructive calculi passed from the upper collecting system into the ureter or infundibulum within 72 hours of decompression, causing acute renal colic and marked obstruction.     

MAG3-F0 scintigraphy in decision making for emergency intervention in renal colic after helical CT positive for a urolith.

Patients with renal colic are evaluated with clinical, laboratory, and imaging methods for stratification for emergency decompression, medical treatment, or discharge and follow up. The current standard practice is heavily based on unenhanced helical CT for detecting uroliths. However, the presence of a urolith does not necessarily mean that the kidney is obstructed and requires emergency decompression. In this study, technetium-mercaptoacetyltriglycine (MAG3) diuretic scintirenography was used to detect obstruction in patients with renal colic. The contribution of this test to patient management after positive findings from helical CT was also studied. METHODS: Diagnostic criteria were established on the basis of previous experience with 60 patients who had renal colic and had undergone radiography of the kidneys, ureters, and urinary bladder (KUB) and diuretic Tc-MAG3 scintirenography and were followed up to correlate scintigraphic findings with clinical outcome. Subsequently, 80 patients with renal colic underwent scintigraphy within 12 h of presentation in the emergency room, after abdominal helical CT showed findings positive for calculus and suggestive of obstruction. After therapeutic oral or intravenous hydration and analgesics, diuretic dynamic renal scintigraphy (flow, function, delayed imaging) was performed after intravenous injections of 10 mCi (370 MBq) 99mTc-MAG3 and 40 mg furosemide (at zero time, or F0). Results were available soon after completion of the study and were considered in patient management. Four characteristic patterns of scintirenography, essential in patient stratification and treatment, had been standardized and were used for interpretation of the studies: the unobstructed kidney; the partially obstructed kidney, proximally or distally obstructed, with mild to severe obstruction and impairment of function; the totally obstructed kidney, with arrested renal function; and the unobstructed but dysfunctioning kidney after decompression, or stunned kidney. RESULTS: Among the 80 patients with positive helical CT findings, 56.5% were found to have obstruction by scintigraphy (32.5% partially, 24% completely); the remaining 43.5% did not have obstruction (21% without an indication of recent obstruction and 22.5% with stunned kidneys after spontaneous decompression). Occasionally, findings of preexistent urine extravasation or infection were present. Patients who, by scintigraphy, never had obstruction or had experienced spontaneous decompression did not require admission or emergency intervention; those with complete or severe obstruction required admission and decompression for relief of pain or restoration of function, whereas those with mild obstruction were treated variably with forced fluids, analgesics, or, less frequently, elective surgery. Outcome information from clinical examination, imaging, and interventional findings indicated that this stratification was successful. The test caused no side effects. CONCLUSION: For renal colic, clinical selection, KUB radiography, and even positive helical CT findings were all found to have a low positive predictive value for obstruction (in this study, 35%, 32%, and 56% respectively). Anatomic studies, including helical CT, should be followed by diuretic MAG3-F0 scintirenography to diagnose and quantify or exclude obstruction, detect spontaneous decompression, and appropriately stratify patients for emergency intervention, observation and medical therapy, or further work-up and discharge with referral to the clinic.     

超声引导微创经皮肾镜取石术治疗复杂性肾结石98例

目的总结应用超声引导微创经皮肾镜取石术(MPCNL)治疗复杂性肾结石的临床经验。方法对98例复杂性肾结石患者施行超声引导MPCNL。结果98例中84例1次成功穿入肾盂,13例2次成功穿入肾盂,1例肾上盏结石穿刺不成功改行其他方法治疗。97例均行一期穿刺取石,其中1次取石成功68例(70.1%),需2次以上取石29例(29.9%)。单通道取石87例(89.7%),多通道取石10例(10.3%)。出院前复查X线片,肾盂结石及梗阻全部解除,遗留肾盏结石13例,结石清除率85.6%。结论B超引导MPCNL治疗复杂性肾结石是一种安全有效的方法。     

白肾28例临床X线分析

目的：白肾是急性完全性输尿管梗阻在静脉尿路造影上的一种重量象，本文目的是探讨其形成机理和输尿管梗阻的成因。材料与方法：回顾性分析经手术和临床Ｘ线确诊的白肾２８例，２７例在常规静脉尿路造影后加照６０、９０ｍｉｎ延迟片，１０例还做了逆行造影，１例行大剂量静脉造影。结果：１７例为阳性结石，１０例为阴性结石，１例为血凝块引起输尿管急性、亚急性完全梗阻；在尿路造影片上表现为随造影时间延长，肾实质密度增高（即     

The 99mTc-DMSA renal scan and 99mTc-DTPA diuretic renogram in children and adolescents with incidental diagnosis of horseshoe kidney

A prospective study was conducted to determine the possibility of obstructive hydronephrosis in horseshoe kidney found incidentally in school children and adolescents by using a radionuclide diuretic renogram. In a 2-year period, 22 school children and adolescents with horseshoe kidney were found in a mass renal sonography survey. They each underwent a 99mTc dimercaptosuccinic acid renal cortical scan to confirm the horseshoe kidney. Each diuretic renogram was performed with the patient in the supine position to rule out obstructive hydronephrosis. The patients were advised to empty their bladders before the intravenous injection of furosemide (1 mg x kg(-1)). The half-time for the clearance of radioactivity from the renal pelvis were calculated. Of the 22 patients, asymmetrical renal cortical function between the two kidneys was found in 14 (63.6%). Eleven kidneys (11/44, 25%) showed stasis of radioactive urine in the renal pelvic region prior to injection of furosemide. There was no incidence of bilateral hydronephrosis in these 22 patients. Only one kidney (1/44, 2.3%) showed obstructive hydronephrosis and five showed clearance of radioactive urine stasis from the renal pelvis immediately after standing up for voiding. There is a low percentage of obstructive hydronephrosis in these cases of horseshoe kidney found incidentally in children and adolescents. A follow-up cohort study on these patients would be valuable for monitoring the development of complications.     

输尿管镜下钬激光治疗妊娠合并输尿管结石

目的探讨输尿管镜下钬激光治疗妊娠合并输尿管结石的可行性及疗效。方法对18例妊娠合并输尿管结石致反复发作肾绞痛的患者先经输尿管镜放置双J管，然后在输尿管镜下钬激光碎石，激光能量0．6～1．0J，频率7～10Hz。结果18例患者术后肾绞痛无再发作，梗阻解除。术后住院2～4d。结论对于保守治疗无效的妊娠合并输尿管结石致反复发作肾绞痛的患者，输尿管镜下钬激光治疗疗效确切、安全可靠。     

Ultrasound in suspected obstruction complicating renal transplantation

The findings of regular ultrasound examination of 439 renal transplants in 419 patients performed during a 16-year period were reviewed to determine the significance of collecting system dilatation. Dilatation was observed in 80 cases. 34 of these proving to be obstructed. Pelvic dilatation was an insignificant finding except when appearing within a month of transplantation. One third of cases developing pelvic dilatation within a month showed progressive dilatation with obstruction subsequently confirmed. The majority of cases developing unheralded dilatation of pelvis and calyces were obstructed and all such patients require further investigation. Recurrence of dilatation following relief of obstruction was associated with recurrent obstruction in eight of nine cases. Consideration of ultrasound appearances allows more critical selection of patients for further investigation when dilatation is seen.     

CT and MR imaging of neurocysticercosis

OBJECTIVE: The purpose of this study was to evaluate whether unenhanced helical CT of the abdomen and pelvis, supplemented as necessary with delayed enhanced CT of the pelvis, is sufficient for urologists to treat patients with acute renal colic. MATERIALS AND METHODS: CT scans from 99 patients were analyzed retrospectively for the presence, size, and location of ureteral calculi and the presence and severity of secondary signs of obstruction. Clinical follow-up was analyzed by reviewing charts, directly communicating with patients, and reviewing surgical reports. Clinical information was correlated with CT findings. RESULTS: The findings of 51 CT scans were positive for calculi, and the findings of 48 were negative for calculi. The findings from two CT scans were false-positive, and none of the findings were false-negative. The sensitivity, specificity, and accuracy of helical CT were 100%, 96%, and 98%, respectively. A significant difference in stone size was found between patients who were treated conservatively (3.3 +/- 1.3 mm) and patients who underwent a urologic procedure (7 +/- 6.2 mm) (p < .01) and between patients in whom successful ureteral stent placement was the sole intervention (3.9 +/- 2.8 mm) and patients in whom initial stent placement failed and who then underwent a second urologic procedure (7.4 +/- 3 mm) (p < .05). We found no statistically significant difference between the conservatively and interventionally treated groups with respect to stone location. The presence and severity of secondary signs of obstruction were not significantly different between the two groups. CONCLUSION: Stone size alone was found to correlate with patient treatment. Stone location and the presence and severity of secondary signs of obstruction did not affect patient treatment. Because the degree of obstruction and relative renal function are not relevant to the initial treatment of patients with ureteral stone obstruction, CT is adequate for both diagnosis and treatment.     

白肾征X线成像机理探讨

目的　探讨白肾征的形成机理与病因。方法　回顾性分析 2 0例白肾的临床资料及X线表现。结果　在静脉肾盂造影片上 ,患肾实质密度逐渐增高 ,肾盂肾盏呈空虚负影或有少量造影剂充盈。 2 0例中 ,输尿管阳性结石 16例 ,输尿管阴性结石 2例 ,腹膜后转移瘤 1例 ,盆腹部放疗后引起 1例。 7例结石排出后 ,1周内复查IVP ,患肾功能恢复正常 ,白肾征消失。结论　白肾出现提示输尿管发生急性梗阻 ,而患肾功能尚未明显受损 ,及时解除梗阻 ,可免患肾功能受到进一步损害。     

Obstructive nephropathy: evaluation with dynamic Gd-DTPA-enhanced MR imaging

The potential of dynamic gadolinium diethylenetriaminepentaacetic acid (DTPA)-enhanced magnetic resonance (MR) imaging for the examination of obstructive nephropathy was analyzed in 27 subjects (five healthy subjects, seven patients with dilated nonobstructed kidneys, six patients with acute obstruction, and nine patients with chronic obstruction) with use of a 1.5-T magnet. Morphologic findings were compared with quantitative analysis of temporal changes in signal intensity. Dynamic postcontrast images of the normal kidney demonstrated four phases of enhancement; cortical enhancement phase, early tubular phase, ductal phase, and excretory phase. The pattern of enhancement in dilated nonobstructed kidneys was similar to that in normal kidneys. In acutely obstructed kidneys, cortical enhancement was similar to that in normal kidneys (17% increase), but medullary enhancement was higher than normal, resulting in diminished corticomedullary differentiation. The early tubular phase was prolonged (until 2.5 minutes after injection), with delayed appearance of the ductal and excretory phases. In chronically obstructed kidneys, the increase in cortical intensity was less than that in normal kidneys (13% increase). The early tubular phase was prolonged, and the ductal phase was diminished or absent.     

F+0 diuresis renography in infants and children.

The purpose of this study was to evaluate the feasibility of modifying diuresis renography by the simultaneous administration of 99mTc-mercaptoacetyltriglycine (MAG3) and furosemide in the investigation of hydronephrosis and hydroureteronephrosis in infants and children. Two parameters were assessed: the diuretic response in normal kidneys and the ability of the F+0 study to differentiate between renal obstruction and nonobstruction and to identify the level of obstruction in cases of renal obstruction. METHODS: Seventy-two patients (48 males, 24 females; age 2 d to 7 y; median age 6 wk) with sonographic diagnoses of hydronephrosis or hydroureteronephrosis were reviewed prospectively over a 3-y period. All patients had prior sonographic studies and micturating cystourethrography. Bladder catheterization was not routinely performed and was undertaken only if the child had suspected vesicoureteric junction (VUJ) obstruction or grade II or more vesicoureteric reflux. A weight-adjusted dose of 99mTc-MAG3 (maximum 200 MBq, minimum 20 MBq) and 1 mg/kg of furosemide (maximum 40 mg) were administered intravenously at the same time. Posterior imaging of the kidneys and bladder was performed for 20 min and followed by gravity-assisted drainage or imaging after voiding. All patients were followed-up for 6-12 mo, and the final diagnoses were based on either surgery or conservative management with repeated sonography or follow-up 99mTc-MAG3 studies (or both). The results of the F+0 diuresis renography were then compared with the final diagnoses. RESULTS: A renal unit was defined as a kidney and its ureter. There were 151 renal units with 1 patient having bilateral duplex kidneys, 6 patients having unilateral duplex kidneys and 1 patient having a solitary kidney. Fifty-five normal renal units and 96 abnormal renal units on the basis of sonographic findings were assessed. The furosemide clearance half-time for the 55 normal renal units was 1.3-6.3 min (mean 3.8 min). Of the 96 abnormal renal units, 53 were classified as nonobstructed and 43 were classified as obstructed. Of the 53 renal units classified as nonobstructed, there were 48 true-negative studies and 5 false-negative studies; of the 43 renal units classified as obstructed, there were 40 true-positive studies and 3 false-positive studies. The sensitivity was 88.9%, specificity was 94.1% and accuracy was 91.7%. The level of obstruction, either pelviureteric junction or VUJ, was also correctly identified. CONCLUSION: F+0 diuresis renography shows excellent diuretic responses in normal kidneys and is a valid method for the investigation of hydronephrosis and hydroureteronephrosis in infants and children.     

Perirenal lucency ("kidney sweat"): a new sign of renal failure.

OBJECTIVE: This study describes a new sonographic finding in renal failure: perirenal lucency, which we call the "kidney sweat" sign. MATERIALS AND METHODS: During 1 year at our institution, 502 renal sonograms were obtained. Sonography evaluated 330 patients with renal failure. All of the examinations were retrospectively analyzed. RESULTS: An extracapsular hypoechoic rim was present in 47 (14%) of the 330 patients with renal failure. The finding, when present, was always bilateral. The hypoechoic rim was not present in the remaining 283 patients with renal failure. Forty (85%) of the 47 patients had kidneys that were hyperechoic compared with the liver. Twenty-eight (60%) of the 47 patients had kidneys that were hyperechoic compared with the spleen. In 15 (32%) of the 47 patients, the kidneys were small. Ascites was present in 11 (23%) of the 47 patients. Of the 283 patients with renal failure whose sonograms did not show the hypoechoic rim, 76 patients had normal sonographic findings. The remaining 207 patients with renal failure who did not show the kidney sweat sign had hydronephrosis, stones, cysts, echogenic kidneys, small kidneys, or ascites. CONCLUSION: An extracapsular hypoechoic rim is found in patients with renal failure. We call this finding "kidney sweat." We believe, but cannot currently prove, that the kidney sweat sign represents edema. It is an additional sonographic finding in patients with renal failure.     

新生儿十二指肠梗阻59例X线分析

目的　探讨新生儿十二指肠梗阻的X线表现。资料与方法　回顾性分析 5 9例新生儿十二指肠梗阻的临床及X线资料 ,其中肠旋转不良 2 7例 ,十二指肠闭锁 2 2例 ,十二指肠狭窄 5例 ,环状胰腺 1例 ,肠旋转不良合并十二指肠闭锁 4例。结果　平片主要表现为单泡 (2 /5 9)、双泡 (48/5 9)、三泡 (5 /5 9)征 ,4 8例双泡征中 14例Dd/Ds(十二指肠泡直径 /胃泡直径 )≥ 1.0 ,其中完全性梗阻 13例 ,与不全性梗阻 1例有显著差异 (P <0 .0 1)。上消化道钡餐显示梗阻端形态呈圆顶状 32例 ,鸟嘴状 2例 ,束腰状 6例 ,不规则状 19例 ;14例显示空肠位置异常。钡灌肠显示盲肠位置异常 7例 (7/10 )。结论　双泡征是十二指肠梗阻最常见的X线征象 ;Dd/Ds≥ 1.0时 ,提示完全性梗阻 ;梗阻端形态对判断十二指肠梗阻的病因帮助不大     

输尿管非结石性梗阻肾积水影像特征分析

目的　分析输尿管非结石梗阻性肾积水的影像特征 ,提高对其的识别能力。方法　根据静脉肾盂造影、逆行尿路造影结果 ,对自 1997-0 1～ 2 0 0 4-0 2经手术和病理证实的输尿管非结石性梗阻肾积水 5 7例的影像及病理资料进行对照分析。结果　中、重度肾积水 47例 ,占 82 .5 % ,其中重度肾积水 2 3例中 ,输尿管肾盂高位连接 12例 ,低位连接 8例 ,输尿管局限狭窄的发病率为85 .1% ,其中输尿管多发和 /或双侧输尿管狭窄的发病率为 2 2 .0 % ,其它原因所致输尿管狭窄的发生率为 14 .9%。结论　输尿管非结石性梗阻的病因具有多样性 ,肾积水的不同影像改变与输尿管病变位置不同密切相关。当一侧肾为重度积水 ,另一侧肾盂表现为“壶腹”型肾盂时应注意排除双侧输尿管存在病变的可能性     

Doppler-duplex ultrasound in renal colic

Objective: To determine the role of intrarenal Doppler ultrasound (US) in patients with renal colic and to establish the usefulness of this diagnostic method. Materials and methods: In 121 patients with renal colic and 70 healthy individuals, 382 kidneys were examined with color duplex US. Mean intrarenal-arterial resistive index (RI), and the difference of mean RIs (dRI) between both kidneys were determined. In 64 patients, RI and dRI were compared with urographic findings (time of delay pyelogram between both kidneys). Results: In the 70 healthy individuals, RI was 0.62 ± 0.045 and dRI 0.018 ± 0.01. In the 121 patients with renal colic, RI (0.71 ± 0.06) was significantly superior (P < 0.001) with respect to the opposite kidney, with a dRI of 0.09 ± 0.055. In a correlation performed in 64 patients with urographic findings among color doppler US, with a RI ≥ 0.70 and/or dRI ≥ 0.06 as an indicative value of obstruction, sensitivity and specifity were 91.8% for patients with delayed pyelogram (n = 37 patients), and 48.1% for patients with nondelayed pyelogram (n = 27 patients) with a specificity of 92.8% with respect to the group of normal patients. In the group of patients with delayed pyelogram, RI was significantly superior (P < 0.05) in patients with an evolution time greater than 24 hours, in patients with proximal ureteral obstruction and in patients who had signs of pyelonephritis. There were no significant differences in the group of patients with nondelayed pyelograms. Conclusion: Color Doppler US is useful to fundamentally evaluate the consequences of the obstruction on renal function. Other factors such as evolution time of the symptomology, obstruction level, or existence of pyelonephritis can alter the US-Doppler values.     

Renal colic: diagnosis and outcome.

To assess whether ultrasonography (US) with or without plain abdominal radiography (kidney, ureter, bladder [KUB] radiography) can replace intravenous urography (IVU) in detection of acute urinary tract obstruction, 101 consecutive patients with renal colic were evaluated with US followed immediately by IVU. Receiver operating characteristic (ROC) curves for US diagnosis of acute urinary tract obstruction yielded sensitivities of 91% and 92% for two reviewers at a specificity of 90%. There was no statistically significant difference between US and IVU results. When US was combined with KUB radiography, ROC curves yielded sensitivities of 94% and 97% for two reviewers at a specificity of 90%.KUB radiography alone was of limited diagnostic value. For US alone, no false-positive results occurred, and the false-negative results (n = 9 and n = 6 for two reviewers) were encountered in cases of grade 1 hydronephrosis and nondilated obstructive uropathy. The authors conclude that US combined with KUB radiography can replace IVU in initial evaluation and follow-up of the great majority of patients with renal colic.