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At least 433 records · Page 24Linked to original sources
PubMed1996

Increased renal function in kidneys with ureteropelvic junction obstruction: fact or artifact? Assessment by quantitative single photon emission computerized tomography of dimercapto-succinic acid uptake by the kidneys.

PURPOSE: We evaluated whether increased differential renal function on the pentetic acid (DTPA) renogram represents elevated renal function in obstructed kidneys. MATERIALS AND METHODS: In 10 patients with unilateral ureteropelvic junction obstruction and a differential function of 53% or greater on the DTPA renogram of the obstructed kidney we performed quantitative single photon emission computerized tomography of dimercapto-succinic acid uptake by the kidneys. RESULTS: The absolute uptake of dimercapto-succinic acid was significantly higher in the obstructed kidneys compared to the contralateral normal kidneys (30.0% +/- 7.8 versus 25.3% +/- 8.2, t = 3.6, p < 0.01, respectively). The elevated absolute uptake in the obstructed kidneys was due to an increased functional volume compared to the contralateral normal kidneys (126.0 +/- 69.7 cc versus 102.3 +/- 59.2 cc, t = 4.4, p < 0.01, respectively). CONCLUSIONS: The results suggest that increased relative renal function in hydronephrotic kidneys due to ureteropelvic junction obstruction is not an artifact of the DTPA renogram. It may represent a compensatory mechanism that sometimes may overcompensate resulting in a paradoxical hyperfunctioning kidney.

Adult↗
PubMed1994

Renal pathology and the 99mTc-DMSA image before and after treatment of the evolving pyelonephritic scar: an experimental study.

This study reports the effects of 3-weeks' antimicrobial treatment on the pathology and appearance of the 99mTc-DMSA renal image in piglets with pyelonephritis induced by a combination of vesicoureteral reflux (VUR) and urinary infection. Before treatment, either photon-deficient (B1, B2) or photon-absent (C) scintigraphic abnormalities were present in the refluxing kidney in all 22 animals examined. All (100%) of the initially B1 and the majority (71%) of B2 photon deficient defects resolved with treatment, leaving only insignificant residual pathologic lesions. Conversely almost all (93%) of the C photon-absent scintigraphic abnormalities persisted after treatment and were always associated with significant scarred or cratered pathologic lesions in the refluxing kidney at sacrifice.

Animals↗
PubMed1994

The selective use of dimercaptosuccinic acid renal scans in children with vesicoureteral reflux.

Dimercaptosuccinic acid (DMSA) renal scans were performed on 75 children (115 refluxing renal units) to determine the efficacy of routine scanning in patients with various grades of vesicoureteral reflux. Cystourethrography demonstrated grades I and II reflux in 75 renal units and grades III to V in 40. Of the patients 51 presented with febrile urinary tract infection and 24 were asymptomatic (patients presenting with nonfebrile urinary tract infections or those undergoing sibling screening). Renal ultrasounds were performed in 60 patients. All patients were initially managed with medical therapy and 19 (25%) ultimately underwent antireflux surgery. DMSA scans demonstrated scarring in 17 of 40 renal units (43%) of patients with high grade vesicoureteral reflux and 6 of 75 renal units (8%) of those with low grade reflux. Renal ultrasounds that were interpreted as normal always correlated to a normal DMSA scan in asymptomatic patients. In patients presenting with febrile urinary tract infections the correlation between ultrasound and DMSA scan was inconsistent. We advocate a tailored approach in the evaluation of patients with vesicoureteral reflux. Renal sonography may be sufficient in the assessment of renal scarring in asymptomatic patients with reflux and those with low grade reflux. Conversely, in patients with high grade vesicoureteral reflux, a history of febrile urinary tract infections and abnormal renal ultrasound DMSA renal scans appear to be most useful.

Child↗
PubMed1994

Prenatal findings associated with a unilateral nonfunctioning or absent kidney.

Prenatal findings in infants who were postnatally found to have a unilaterally nonfunctioning cystic, dysplastic or absent kidney were evaluated to understand better the prenatal pathophysiology of these conditions. Of the 38 cases in which prenatal and postnatal renal imaging studies were done fetal renal conditions leading to postnatal dysplasia or absence included small echogenic kidneys in 3, typical multicystic dysplasia in 30, obstructive uropathy in 4 and perinephric urinoma in 1. Abnormalities were noted on postnatal imaging in 30% of the contralateral kidneys. Vesicoureteral reflux was the most commonly identified abnormality, occurring in 23% of the cases.

Female↗
PubMed1994

Renal pathology and the 99mTc-DMSA image during the evolution of the early pyelonephritic scar: an experimental study.

This study describes the pathologic changes underlying the appearances of the 99mTc-DMSA renal image during acute pyelonephritis induced in piglets by a combination of vesicoureteral reflux (VUR) and urinary infection. In a total of 42 animals examined, pathologic lesions were identified in 36 of the 46 kidneys subjected to VUR and urinary infection, but no lesions developed in the remaining 10 refluxing kidneys. While scintigraphic defects were invariably associated with pyelonephritic lesions (specificity 100%), some small lesions were not identified (sensitivity 80%). There was a significant association (p = < 0.001) between the degree of photon deficiency seen scintigraphically and the histologic changes (early and late lesions). However, the scintigraphic appearance of individual lesions was also influenced by factors such as their extent and density, so that consideration of the macroscopic characteristics was also important for precise correlation.

Acute Disease↗
PubMed1993

The diagnosis of acute pyelonephritis in the piglet using single photon emission computerized tomography dimercaptosuccinic acid scintigraphy: a pathological correlation.

Single photon emission computerized tomography (SPECT) scintigraphy has proved to be an extremely sensitive renal imaging modality in children with genitourinary pathology, including pyelonephritis, particularly when compared to 2-dimensional planar imaging. This study was undertaken to corroborate SPECT dimercaptosuccinic acid (DMSA) scintigraphic findings with specific histopathology in acute pyelonephritis. Unilateral vesicoureteral reflux was produced in 19 Yorkshire piglets 3 to 4 weeks old. The bladders of 12 animals were inoculated with Escherichia coli 2 weeks later, after baseline SPECT DMSA scans had been obtained. The animals were then re-imaged at 3 (4), 7 (4) or 14 (4) days after infection and sacrificed for histological evaluation. Seven purposefully uninfected piglets with unilateral reflux served as controls and were followed for up to 6 weeks before imaging and sacrifice. SPECT proved to be 97% sensitive and 93% specific in providing the diagnosis of acute pyelonephritis. The SPECT findings were manifest by a spectrum of abnormal findings (mottling, striations, inner cortical scalloping and focal cortical defects), which correlated precisely with the extent and severity of cortical involvement in the acute pyelonephritic process. We propose a new classification scheme for SPECT DMSA renal scintigraphic imaging, and believe that this modality is exquisitely sensitive in providing the diagnosis as well as in evaluating the extent of renal parenchymal involvement when acute pyelonephritis is induced in the animal model.

Acute Disease↗
PubMed1992

Use of 99mtechnetium-dimercaptosuccinic acid to study patterns of renal damage associated with prenatally detected vesicoureteral reflux.

Static isotope imaging with 99mtechnetium-dimercaptosuccinic acid was performed at a mean age of 34 days in 32 children (50 kidneys) whose vesicoureteral reflux had been identified as a result of prenatal ultrasound scanning. Three patterns of isotope uptake were observed: 1) noninfected primary vesicoureteral reflux (15 children, 24 kidneys), 2) noninfected secondary (obstructed) vesicoureteral reflux (9 patients, 11 kidneys) and 3) infected primary reflux (8 infants, 15 kidneys). In 20 pattern 1 kidneys (83%) renal morphology and differential isotope were normal. In the 4 kidneys (17%) that showed evidence of impaired function this took the form of global parenchymal loss, that is small kidneys rather than focal scarring. In pattern 2 the combination of fetal vesicoureteral reflux and obstruction was a potent cause of renal damage with total or near total loss of function in 7 of 9 refluxing units associated with posterior urethral valves and in 2 kidneys with secondary ureteropelvic junction obstruction. Appearances of focal scarring were confined in pattern 3 and were found in 4 kidneys (27%). This overall incidence of detectable renal damage was lower than expected. Even when infection occurs, prenatal diagnosis may lessen the risk of scarring by enabling treatment to be instituted promptly. The findings suggest that uncomplicated primary vesicoureteral reflux is a relatively benign insult to the fetal kidney and that reflux nephropathy found in children presenting clinically is the result of infected vesicoureteral reflux in postnatal life. Any comparison of published studies will prove difficult until there is a more standardized approach to imaging technique and patient selection.

Female↗
PubMed1992

Dimercaptosuccinic acid renal scintigraphy for the evaluation of pyelonephritis and scarring: a review of experimental and clinical studies.

Renal cortical scintigraphy has been reported to be useful in children for confirmation of the diagnosis of acute pyelonephritis. Subsequent experimental studies have demonstrated that dimercaptosuccinic acid (DMSA) scintigraphy, when compared directly with histopathology, is highly reliable for the detection and localization of parenchymal inflammatory changes associated with acute pyelonephritis. Recent clinical studies of acute pyelonephritis using DMSA scintigraphy reveal that the majority (50 to 91%) of children with febrile urinary tract infections have abnormal DMSA renal scan findings and that the majority of these children do not have demonstrable vesicoureteral reflux. However, when vesicoureteral reflux is present, renal cortical abnormalities are demonstrated by DMSA scintigraphy in 79 to 86% of the kidneys. In children with febrile urinary tract infections routine clinical and laboratory parameters are not reliable in the differentiation of acute pyelonephritis, documented by DMSA renal scan findings, from urinary tract infections without parenchymal involvement. Furthermore, the presence of P-fimbriated Escherichia coli associated with febrile urinary tract infections does not reliably predict those kidneys that have acute parenchymal inflammation demonstrated by DMSA renal scans. DMSA is also the isotope agent of choice for the detection of renal scarring. Clinical studies report greater sensitivity of DMSA renal scintigraphy for the detection of renal scarring when compared with the excretory urogram, particularly in infants and young children. In a recent prospective study of post-pyelonephritic renal scarring in children we found that acquired renal scarring only occurs in sites corresponding exactly to previous areas of acute pyelonephritis demonstrated by DMSA scintigraphy at the time of infection. Furthermore, once acute pyelonephritis occurs, ultimate renal scarring is independent of the presence or absence of vesicoureteral reflux. These findings provide convincing evidence that renal parenchymal infection, rather than vesicoureteral reflux, is the prerequisite for acquired (postnatal) renal scarring. Vesicoureteral reflux as a risk factor for acquired renal scarring is directly related to its role as a risk factor for acute pyelonephritis. We conclude that DMSA scintigraphy is a valid tool for confirming the diagnosis of acute pyelonephritis in children and for identifying kidneys at risk for subsequent renal scarring.

Acute Disease↗
PubMed1992

Evaluation of acute urinary tract infection in children by dimercaptosuccinic acid scintigraphy: a prospective study.

A prospective study examining the incidence of dimercaptosuccinic acid (DMSA) abnormalities in children at the time of acute urinary tract infection, the progression of these abnormalities following treatment and their correlation with the presence of vesicoureteral reflux is reported. DMSA scans performed within 72 hours of presentation in 65 previously healthy children with acute urinary tract infection were abnormal in 34 (52%). The scan appearances of 30 of 36 (83%) initially abnormal kidneys improved or became normal on the repeat DMSA study performed at 3 to 6 months after the acute urinary tract infection. A cystogram demonstrated significant vesicoureteral reflux in 11 of 45 cases (24%). Of these 11 cases 10 had abnormal DMSA studies and 1 had dilated upper tracts on ultrasound. Several conclusions may be drawn from our study. The incidence of DMSA abnormalities at the time of acute urinary tract infection is high but these abnormalities tend to resolve with time. An abnormal DMSA study at the time of urinary tract infection identifies most children with significant vesicoureteral reflux, and in our series a combination of ultrasound and DMSA identified all cases. This study may have major implications for the clinical investigation of children with urinary tract infection.

Acute Disease↗
PubMed1992

Renal scarring following reflux and nonreflux pyelonephritis in children: evaluation with 99mtechnetium-dimercaptosuccinic acid scintigraphy.

99mTechnetium dimercaptosuccinic acid (DMSA) scintigraphy is the imaging modality of choice for the detection of acute pyelonephritis and chronic renal scarring in children. Using the DMSA scan we prospectively evaluated renal scarring after reflux and nonreflux pyelonephritis in children. The study population consisted of 33 patients with acute pyelonephritis documented by a DMSA renal scan at infection. The children were evaluated for renal scarring with a followup DMSA scan 4 to 42 months (mean 10.7 months) after the acute infection. All new scarring on followup DMSA scans occurred at sites corresponding exactly to areas of acute inflammation on the initial DMSA scan. Therefore, only those kidneys with acute changes on the initial scan were subsequently analyzed. Of 38 kidneys new or progressive scarring developed in 16 (42%), including 6 of 15 (40%) with associated vesicoureteral reflux and 10 of 23 (43%) without demonstrable reflux. New renal scarring developed in 6 of the 7 kidneys (86%) associated with a neuropathic bladder or posterior urethral valves. In contrast, new scarring developed in only 10 of 31 kidneys (32%) associated with a normal bladder (p = 0.028). Excluding the kidneys associated with a neuropathic bladder or posterior urethral valves, new renal scarring developed in 3 of 12 (25%) with primary reflux, compared with 7 of 19 (37%) without vesicoureteral reflux. Except for the white blood count and the species of infecting bacteria, no other statistically significant differences could be found between those cases in which scars did or did not develop. We conclude that acquired renal scarring only occurs at sites corresponding to previous areas of acute pyelonephritis, the acute parenchymal inflammatory changes of acute pyelonephritis are reversible and do not lead to new renal scarring in the majority of cases, and once acute pyelonephritis has occurred ultimate renal scarring is independent of the presence or absence of vesicoureteral reflux.

Adolescent↗
PubMed1991

Spontaneous recovery of renal function after resection of contralateral hypernephroma.

We report a case of nonfunction of an anatomically normal kidney associated with a contralateral hypernephroma. X-ray and radionuclide imaging suggested a disturbance of the contralateral renal blood flow at the microvascular level. Normal function resumed after tumor resection. The implications for management are discussed.

Carcinoma, Renal Cell↗
PubMed1991

The detection of reflux nephropathy in infants by 99mtechnetium dimercaptosuccinic acid studies.

Dimercaptosuccinic acid (DMSA) studies were performed in 113 infants less than 1 year old at risk of renal scarring. Of these patients 86 presented with urinary tract infection and 27 were asymptomatic. A voiding cystourethrogram was performed in all cases and excretory urography (IVP) was done in 99. More abnormalities were detected by DMSA study when compared to scars on IVP. When both studies were abnormal there was an excellent correlation on a site by site basis. Fever or systemic disorder was not a reliable sign to determine whether there was upper tract involvement with infection. The incidence of DMSA abnormalities in infants increased with high grade vesicoureteral reflux and decreased with low grade reflux. There was no significant difference in the incidence of abnormal kidneys between the infected and noninfected groups, suggesting that renal scarring may occur with sterile reflux.

Female↗
PubMed1989

99mtechnetium-dimercapto-succinic acid renal scanning and excretory urography in diagnosis of renal scars in children.

We compared the ability of excretory urography (without tomography) and 99mtechnetium-dimercapto-succinic acid renal scanning to detect renal scars in 32 children with primary vesicoureteral reflux. These children did not have hydronephrosis, renal failure or urinary tract obstruction. In all cases both studies were conducted within a 10-month period. The findings from both modalities were in agreement for 51 of the 64 renal units evaluated (80 per cent). Evaluation of the excretory urogram indicated 6 cases of diffuse and 2 of focal scarring that were not detected by evaluation of the renal scan. The sensitivity of excretory urography to detect renal scars was 84 per cent and the specificity was 83 per cent. The 99mtechnetium-dimercapto-succinic acid renal scan showed 5 cases of focal renal scarring not detected by excretory urography. The sensitivity of the renal scan to detect renal scars was 77 per cent and the specificity was 75 per cent. We conclude that neither study alone could effectively replace the other for the detection of renal scars, and recommend that both be included in the initial evaluation and followup of patients with renal scars.

Adolescent↗
PubMed1989

Experimental obstructive hydronephrosis in newborn rats. XI. A one-year follow-up study of renal function and morphology.

Partial obstruction of the left ureter was created in two-day-old rats and its effects on kidney function were studied with 99mTc-DMSA and 99mTc-DTPA after one, two, three and six weeks, and after one year. Kidneys from animals sacrificed at the age of six weeks or one year were also examined histologically. The obstructed renal pelvis was enlarged by about 35 times and there was a delayed excretion of 99mTc-DTPA during forced diuresis, indicating significant, chronic obstruction. The renal DMSA-uptake ratio (left kidney/(left and right kidney] was reduced to about 40% from the first week of obstruction. The parenchymal weight ratio (expressed as above) was reduced to about 45% after both six weeks and one year. The glomerular filtration rate, examined during forced diuresis and calculated on the basis of uptake capacity, was lowered to 42% after six weeks but was not significantly reduced after one year of obstruction. The incidence figures for medullary hemorrhage or accumulation of iron pigment, and chronic inflammatory changes in the cortex were somewhat higher after one year of obstruction than after 6 weeks, but the lesions were patchy in both groups. We conclude that partial unilateral ureteric obstruction, created in the neonatal period, leads to a slight but permanent functional disturbance and parenchymal weight reduction without prominent structural parenchymal damage.

Animals↗
PubMed1990

Renal scarring and vesicoureteral reflux in children with myelodysplasia.

The records of 180 myelodysplasia patients followed from 3 to 18 years were reviewed. Studies included cystography to evaluate vesicoureteral reflux and dimercapto-succinic acid renal scintigraphy to identify acute inflammation and renal scarring. Scarring was noted in 28 of 180 patients (15.5%), of whom 68% were girls. Of the patients with renal scarring 75% had associated reflux and 40% over-all were identified as having reflux. Management of patients with vesicoureteral reflux included clean intermittent catheterization, antibiotic prophylaxis and anticholinergics when indicated. Only 17 of 72 patients (24%) had ureteral reimplantation. Surgical indications included persistent high grade reflux and/or progressive upper tract damage. Reflux resolved in 62% of those on medical management. Resolution was not dependent on grade of reflux (as compared to primary reflux). Twenty-one patients are stable and being followed with persistent reflux. In 7 patients new renal scars developed during aggressive medical management, 5 of whom underwent subsequent surgical correction.

Child↗
PubMed1990

High resolution single photon emission computerized tomography (SPECT) 99mtechnetium-dimercapto-succinic acid renal imaging: a state of the art technique.

The 99mtechnetium-dimercapto-succinic acid renal scan has become the gold standard for evaluating renal parenchymal pathology. The traditional pinhole technique provides 2-dimensional imaging. Recent application of high resolution single photon emission computerized tomography (SPECT) has provided the means to obtain even greater cortical detail. With 360-degree imaging and computer reconstruction, SPECT provides coronal, sagittal and transaxial imaging. We prospectively compared the SPECT and pinhole techniques in 33 patients (65 renal units) ranging in age from 2.5 months to 18 years. Both scans were obtained in all patients. All scans were reviewed by an independent interpreter. Using SPECT imaging, diagnostic information was enhanced in 46 of the 65 kidneys (71%). Of the 24 kidneys that appeared "normal" by pinhole imaging 15 (63%) had defects on SPECT imaging. High resolution SPECT imaging improves the ability to identify cortical defects and visualize asymmetry of cortical thickness compared to standard pinhole imaging.

Adolescent↗