The interrenicular junction: a mimic of renal scarring on normal pediatric sonograms

A triangular, echogenic focus of perirenal tissue in the anterosuperior or posteroinferior margin of the kidney, the junctional parenchymal defect (JPD), and an oblique echogenic line, the interrenicular septum (IRS), connecting the JPD to the renal hilum are normal sonographic findings in the pediatric age group. They are manifestations of an oblique interface between the two parts (reniculi) of one kidney. They should not be mistaken for renal scars. Prospectively, in a group of 100 children, either the JPD or IRS was seen in 46% of right kidneys and 19% of left kidneys. Retrospectively, the JPD was seen in 47% of right kidneys and 18% of left kidneys, and the IRS was seen in 39% of right kidneys and 12% of left kidneys.     

Replacement lipomatosis: CT and MRI findings of a rare renal mass

Replacement lipomatosis of the kidney (RLK) is an advanced form of renal sinus lipomatosis, in which infection, renal calculi and long-standing hydronephrosis are accompanied by renal parenchymal atrophy. The kidneys are usually poor or non-functioning. We present CT and MRI findings of an unusual focal RLK of a 52-year-old male, who was examined with the suspicion of renal malignancy.     

Quantitative SPET 99Tcm-DMSA uptake by the kidneys: age-related decline in healthy males

To evaluate if 99Tcm-dimercaptosuccinic acid (99Tcm-DMSA) uptake by the kidneys is related to age and creatinine clearance in males with normal renal function, quantitative single photon emission tomography (SPET) of DMSA uptake by the kidneys was performed in 18 volunteers aged 20-79 years. The quantitative uptake of DMSA in the right kidney was 13.9 +/- 2.9% and in the left kidney 14.2 +/- 3.0%. There was no statistically significant difference between left and right kidney uptake (t = 1.2, N.S.). Global kidney uptake (right + left) was 28.1 +/- 5.9%. There was a statistically significant age-related decline in global DMSA uptake. The estimated DMSA uptake (%) was given by -0.27 x age + 42 (r = -0.87, P < 0.001). A good correlation was found between creatinine clearance and global DMSA uptake (r = 0.87, y = 2.8x + 28.3, P < 0.001). The results suggest that normal values of DMSA uptake by the kidneys are age-dependent.     

MDCT Findings of Right Circumaortic Renal Vein with Ectopic Kidney

Anomalies of renal vasculature combined with ectopic kidneys were found on a multi-detector CT scan. Knowledge of renal vascular variation is very important for surgical exploration, radiologic intervention and staging for urologic cancer. We present an extremely rare case of a right circumaortic renal vein combined with a right ectopic kidney. The right kidney was located at the level between the third and fifth lumbar vertebra. The right circumaortic renal vein crossed the aorta and returned to the inferior vena cava behind the aorta.     

Primary obstructive megaureter--an unusual presentation

A rare presentation of primary obstructive megaureter as an asymptomatic pyeloureteral cast in a non-functioning kidney is presented.     

Unilateral duplicated system: comparative length and function of the kidneys

OBJECTIVE: The objective of this study was to estimate kidney length and function in patients with unilateral duplex kidney. MATERIALS AND METHODS: Thirteen patients with a unilateral duplicated system were reviewed retrospectively. The length of the kidneys was measured by ultrasound, and the relative function of the kidneys was estimated by renal scan. RESULTS: In all patients, the duplex kidney was the left one. The length of the right kidney on the renal ultrasound growth chart was from -1.5 to +0.4 standard deviations from the mean for age, and the left kidney length was from -0.5 to +4.3 standard deviations from the mean. On renal scans the kidneys with a duplicated system contributed 51 to 67% to total renal function; the contralateral ones, 33 to 49%. CONCLUSIONS: Kidneys with a duplicated system may be larger than their counterparts and they may contribute more to total renal function. When a disparity in length between the 2 kidneys is encountered, 1 of the possibilities that should be taken into account is a unilateral duplicated system.     

The relationship between renal parenchymal mass and absolute quantitation of 99Tcm-DMSA uptake. An experimental study in the growing pig

Five Gottingen minipigs from the same litter aged 1 month entered the study and right nephrectomies were performed at staggered intervals between weeks 1 and 5. Absolute renal uptake of 99Tcm-DMSA, expressed as a percentage of the administered dose, was recorded in each animal weekly before right nephrectomy and at weekly intervals for 5 weeks post-nephrectomy. Before nephrectomy absolute renal uptake of 99Tcm-DMSA ranged between 16.8 and 21.5% (mean 18.6%) per kidney with no difference between right and left kidneys. After right nephrectomy, uptake in the left kidney approximately doubled within 1 week. No correlation was shown between renal parenchymal mass and absolute 99Tcm-DMSA uptake in paired or solitary normal kidneys undergoing growth or compensatory growth.     

Renal autotransplantation in management of bilateral ureteral mortar shell injuries: a case report

We present a 36-year-old female patient who was injured in the pelvic region by a mortar shell fragment. The trauma comprised a complex lesion to both ureters, to the urinary bladder, and to the pelvic brim. The ruptured urinary bladder was sutured and a bilateral ureterocutaneostomy was performed in a hospital near the front line. Because of a large scar and the right ureter necrosis, a kidney autotransplant was performed 3 months later. A left ureterocystoneostomy was done. Five years later, because of urosepsis and hydronephrosis caused by a ureteral calculus, a nephrostomy was placed in the proximal right ureter, antibiotic treatment was prescribed, and the calculus was managed by crushing the stones using extracorporeal shock wave lithotripsy. Ten years after the initial trauma, the patient is well, has normal micturition, and both of her kidneys are functioning normally.     

Intrathoracic and intra-abdominal Tl-201 abnormalities seen on rotating raw cine data on dual radionuclide myocardial perfusion and gated SPECT.

PURPOSE: The lower thorax and upper abdomen are visualized during cardiac acquisition of rest Tl-201 and stress Tc-99m tetrofosmin gated SPECT. Thus, abnormal Tl-201 localization in these areas and in organs such as parts of the lungs, liver, spleen, and kidneys can be observed, including rotating raw cine data. MATERIALS AND METHODS: Other than cardiac images, the authors retrospectively reviewed Tl-201 rotating (raw data) images of 235 patients. Abnormal findings in the lungs, liver, spleen, and kidneys were identified that correlated with the patients' clinical information; radiographic findings, including computed tomography and ultrasonography of the abdomen; other scintigraphic studies; and laboratory findings. RESULTS: In 53 patients, 54 abnormalities were detected. Intrathoracic abnormalities included focal areas of increased uptake, one in the right lower lung and another in the right upper lung that confirmed lung cancer, in 2 patients; diffuse uptake in both lungs in 11 patients; photopenia in the lung bases, which had resulted from pleural effusions, in 3 patients; and abnormal right liver configuration caused by elevation of the right hemidiaphragm in 1 patient. Of the intra-abdominal abnormalities, 12 patients with splenomegaly were identified. Six patients had focal areas of increased uptake in the gastric area. Nonvisualization of one kidney resulted from a congenitally absent right kidney in 1 patient, from right nephrectomy in 1 patient, from end-stage renal disease in another, and from a lower position of the left or right kidneys in 5 patients. Small and decreased uptake of both kidneys resulted from end-stage renal disease in 1 patient. Small and decreased uptake of one kidney was noted in 1 patient with renal scarring, in 1 patient with a renal stone, in 3 patients with chronic pyelonephritis, and in 5 patients with renal cyst(s). CONCLUSIONS: Discernible intrathoracic and intra-abdominal abnormalities using rotating raw cine data from imaging in three-dimensional displays include diffuse or focal pulmonary uptake, pleural effusion, elevation of a hemidiaphragm, splenomegaly, increased uptake in the gastric area, renal abnormalities including absent or small kidneys, end-stage renal disease, renal scarring, renal cyst(s), and lower position of a kidney. The incidental finding of such abnormalities may prompt further clinical investigation.     

Functional changes in the pig kidney following irradiation with fractionated doses of fast neutrons (42 MeVd-->Be).

The right kidney of female Large White pigs, approximately 14 weeks old, was irradiated with fractionated doses of fast neutrons (42 MeVd-->Be). The total doses used were 6.6-9.2 Gy. Changes in kidney function, assessed as the functional index (FI, where FI = irradiated kidney function/unirradiated kidney function) or as individual kidney glomerular filtration rate (GFR) and effective renal plasma flow (ERPF), were serially determined up to 104 weeks after irradiation using 99Tcm-DTPA and 131I-hippuran renography. The animals were then euthanized, the kidneys removed and weighed. A dose-dependent reduction in FI was seen within 13 weeks of irradiation. Measuring individual kidney function revealed a hyperaemic response in both irradiated and unirradiated kidney 4 weeks after irradiation. This was followed by a dose-dependent reduction in irradiated kidney GFR and particularly ERPF. The ED50 value for the impairment in ERPF, assessed as the percentage of irradiated kidneys exhibiting a > or = 50% reduction in ERPF, was significantly lower than that for GFR, i.e. 7.20 +/- 0.10 Gy compared with 8.44 +/- 0.07 Gy (p < 0.001). A dose-related reduction in irradiated kidney weight was also observed. These fast neutron-induced changes in renal function and weight are qualitatively similar to those observed following photon irradiation of the pig kidney.     

先天性肛门闭锁异位肾SPECT/CT显像一例

笔者报道了先天性肛门闭锁异位肾SPECT/CT显像一例。异位肾患者由于早期缺乏特异性的临床症状,大多数患者都是体检时偶然发现。目前诊断异位肾主要靠超声及CT,但是对异位肾分肾肾功能的评价,肾动态显像具有明显的优势。笔者通过文献复习加深了对Gate's法的认识,结合该病例得出指导性结论:1、对已发现有一器官畸形的新生儿,应该留意是否合并其他器官的畸形,做到早发现早干预;2、SPECT/CT可对异位肾的形态及功能进行一站式诊断,优势明显;3、对于特殊肾脏的肾小球滤过率的测定,Gate's法需要适当的矫正。     

Improvement of MRI-functional measurement with automatic movement correction in native and transplanted kidneys

PURPOSE: To improve 2D software for motion correction of renal dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and to evaluate its effect using the Patlak-Rutland model. MATERIALS AND METHODS: A subpixel-accurate method to correct for kidney motion during DCE-MRI was evaluated on native and transplanted kidneys using data from two different institutions with different magnets and protocols. The Patlak-Rutland model was used to calculate glomerular filtration rate (GFR) on a voxel-by-voxel basis providing mean (Kp) and uncertainty (sigma(K(p))) values for GFR. RESULTS: In transplanted kidneys, average absolute variation of Kp was 6.4% +/- 4.8% (max = 16.6%). In native kidneys average absolute variation of Kp was 12.11% +/- 6.88% (max = 25.6%) for the right and 11.6% +/- 6% (max = 20.8%) for the left. Movement correction showed an average reduction of sigma(K(p)) of 6.9% +/- 6.6% (max = 21.4%) in transplanted kidneys, 30.9% +/- 17.6% (max = 60.8%) for the right native kidney, and 31.8% +/- 14% (max = 55.3%) for the left kidney. CONCLUSION: The movement correction algorithm showed improved uncertainty on GFR computation for both native and transplanted kidneys despite different spatial resolution from the different MRI systems and different levels of signal-to-noise ratios on DCE-MRI.     

正常成人肾脏磁共振扩散加权成像研究

目的 通过测量正常成人肾脏磁共振扩散加权成像(DWI)时的表观弥散系数(ADC)值,为肾脏病变患者在DWI成像时提供正常对照标准.资料与方法 20例健康志愿者均行MRI常规平扫及DWI成像,DWI成像时b值分别采用0s/mm2、200s/mm2、500s/mm2、800s/mm2、1000s/mm2.结果 不同b值下双侧肾脏皮髓质ADC值及双侧肾脏平均ADC值差异有统计学意义(F=57.863～240.324,P=0.000),双侧肾脏皮髓质ADC值及平均ADC值均高于肝、脾及胰腺ADC值.双侧肾脏皮质在不同b值下的ADC值均高于髓质,差异有统计学意义(t=8.436～20.281,P=0.000).左侧肾脏皮、髓质ADC值及平均ADC值在b=500s/mm2、b=800s/mm2及1000s/mm2时均高于右侧,差异有统计学意义(b=800s/mm2时t=2.023,P=0.048;其余P=0.000).b=200s/mm2时双侧肾脏皮、髓质ADC值及平均ADC值之间差异无统计学意义(t=1.739,P=0.098;t=0.704,P=0.490;t=-0.314,P=0.757).结论 正常成人肾脏ADC值在不同b值下有差异,双侧肾脏平均ADC值亦存在差异.     

In vivo estimation of renal volume using a rotating gamma camera for 99mTc-dimercaptosuccinic acid renal imaging

The in vivo renal volume was determined using SPECT for ^99mTc-DMSA renal imaging. The total renal volume was derived by summing the DMSA distribution volumes of the transaxial slices in the whole kidney. In 20 healthy subjects the renal volume in the right kidney was 220 ml for men and 195.2 ml for women, while that in the left kidney was 213 ml for men and 193.7 ml for women. Differences in those values were not statistically significant. A good correlation was found between renal volumes in both kidneys and body surface area. In 106 kidneys including solitary and pathological kidneys, individual renal volume correlated well with individual DMSA renal uptake rate which demonstrates cortical functioning mass, depending on the cortical blood flow. Thus, SPECT enables an accurate noninvasive means of estimating in vivo functioning renal volume.     

Imaging of a supernumerary kidney

A 33-year-old female patient was investigated for a right lower quadrant pain. The investigation, which included an excretory urography and a computed tomography examination, revealed a normal kidney on the right side and another two normal sized, complete kidneys on the left side, which appeared to have a small parenchymal bridge. The patient was treated surgically for a cyst of the right ovary. Received: 12 October 1999; Revised: 28 January 2000; Accepted: 16 March 2000     

磁性药物靶向治疗中MRI检测磁流体体内分布的实验研究

目的:利用MRI技术探讨在磁性药物靶向治疗中磁流体作为药物载体的体内靶向性.材料和方法:取大鼠6只,实验组和对照组各3只.将对照组大鼠从股静脉注射磁流体,同时将实验组大鼠的右肾部位置于C型磁体中,从股静脉注射磁流体后持续置于磁体中1小时,取出半小时后同对照组大鼠一同进行MR扫描,分别检测磁流体在各大鼠右肾部位的分布情况.结果:从MRI图像中可以明显看出大鼠右肾部位的信号强度大大减小,有较高浓度的磁流体在右肾部位聚集.结论:采用磁流体作为药物的载体,在外磁场作用下可实现靶向控制,提高药物在靶部位的聚集浓度.选用磁共振成像技术检测磁流体在体内的聚集情况是行之有效的.     

Knowledge-based segmentation of pediatric kidneys in CT for measurement of parenchymal volume

PURPOSE: The purpose of this work was to develop an automated method for segmenting pediatric kidneys in helical CT images and measuring their volume. METHOD: An automated system was developed to segment the kidneys. Parametric features of anatomic structures were used to guide segmentation and labeling of image regions. Kidney volumes were calculated by summing included voxels. For validation, the kidney volumes of four swine were calculated using our approach and compared with the "true" volumes measured after harvesting the kidneys. Automated volume calculations were also performed in a cohort of nine children. RESULTS: The mean difference between the calculated and measured values in the swine kidneys was 1.38 ml. For the pediatric cases, calculated volumes ranged from 41.7 to 252.1 ml/kidney, and the mean ratio of right to left kidney volume was 0.96. CONCLUSION: These results demonstrate the accuracy of a volumetric technique that may in the future provide an objective assessment of renal damage.     

The effect of post-mortem computed tomography angiography (PMCTA) using water-soluble,iodine-based radiographic contrast on histological analysis of the liver,kidneys and left ventricle of the heart

The purpose of this study was to investigate the impact of post-mortem computed-tomography angiography (PMCTA) on the histology of the liver, kidneys and heart. Multiple tissue cores were collected from the liver, left and right kidneys and left ventricle utilizing CT-guided biopsy. Subsequent whole body PMCTA was performed using a solution of polyethylene glycol and iodinated radiographic contrast, and an embalming pump. Corresponding biopsy cores were collected at autopsy, and blinded histology analysis assessing for PMCTA-induced histology artefact was performed. The blinded analysis of pre-PMCTA and post-PMCTA biopsy samples demonstrated that whole body PMCTA had no effect on the histological analyses of the liver (0%, CI = 0–13.7%), left ventricle of the heart (0%, CI = 0–36.9%) and right kidney (0%, CI = 13.2%), however likely caused increased Bowman’s capsule spaces in the left kidney of one case (4%, CI = 0.01–20.4%). Other artefactual histological changes identified included eosinophilic material in the liver, whiter interstitium and dilated tubules in kidney samples, and autolysis-related changes, however these could not be categorically attributed to the PMCTA procedure. PMCTA causes zero or minimal effect to the histological examination of the liver, left kidney, right kidney and left ventricle, and as such performing PMCTA prior to autopsy is unlikely to impact autopsy histological results in these organs.     

Ultrasound diagnosis of horseshoe kidney

Ultrasound diagnosis of horseshoe kidneys depends on the demonstration of an isthmus or band of renal tissue across the midline of abdomen connecting the lower poles of the kidneys. In a number of cases this band of renal tissue may evade ultrasonic detection. In a series of 11 patients with horseshoe kidneys, sonographic detection of renal isthmus was achieved in seven patients, but in all 11 cases there was demonstrable alteration of renal outlines. Instead of normal reniform shape, the kidneys appeared "inverted pyriform" or "inverted triangular". Detection of such an altered renal outline should raise suspicion of horseshoe kidney.     

Comparison of 99Tcm dimercaptosuccinic acid scans and intravenous urography in children

A retrospective comparison of 99Tcm dimercaptosuccinic acid (DMSA) scans and intravenous urograms (IVUs) was performed on a large, unselected paediatric population to assess critically the relative merits of these two techniques. A total of 205 children were studied, providing 388 kidneys for comparison. The studies agreed in 81%, both being normal in 39%, and both abnormal in 42%. In 28 kidneys (7%), the IVU was abnormal when the 99Tcm DMSA was normal. There was a collecting system abnormality in 27 kidneys, but 10 kidneys also showed a parenchymal abnormality. In all these the parenchymal abnormality was global thinning on the IVU, and the contralateral kidney was small. In 40 kidneys (10%) the 99Tcm DMSA was abnormal when the IVU was normal: the abnormalities demonstrated were predominantly focal defects. After excluding IVUs of poor diagnostic quality, only 14 kidneys (3.6%) showed this disparity. The important clinical subgroups are infection, with or without reflux (27 kidneys), hypertension (4) and neonates with poor renal function (2). The one false positive 99Tcm DMSA was a result of an anatomical variant. Global thinning in a "normal" kidney on a 99Tcm DMSA scan may be overlooked when the contralateral kidney is poorly functioning and small.