Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022672 (acute tubular necrosis)
 2,175 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Magnetic resonance imaging (MRI) was compared with radionuclide scintigraphy (RNS) in 16 patients with renal transplants undergoing renal failure to determine which modality could best discriminate between rejection, acute tubular necrosis (ATN), and cyclosporin nephrotoxicity (CN). Although all rejecting transplants had reduced corticomedullary differentiation (CMD) on T1-weighted MR images, four of five cases of ATN had appearances that could not be distinguished from rejection. A normal CMD suggests nonrejection, but diminished CMD is nonspecific. Tc-99m DTPA/I-131 hippuran RNS was superior to MRI in differentiating rejection from ATN. Although ATN and CN have similar RNS patterns, this distinction can usually be made based on the clinical time course. Other potential uses of MRI in the evaluation of the renal transplants are discussed.
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PMID:Comparison of magnetic resonance imaging and radionuclide imaging in the evaluation of renal transplant failure. 328 80

Absent renal perfusion on a Tc-99m DTPA radionuclide study was observed in a patient with acute tubular necrosis following rhabdomyolysis. Complete recovery was achieved with conservative treatment. Absence of renal perfusion does not indicate a nonviable kidney.
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PMID:Acute tubular necrosis secondary to rhabdomyolysis with complete absence of renal perfusion. 329 56

Sequential fast magnetic resonance (MR) images (repetition time = 33 ms, echo time = 7 ms, alpha = 22 degrees, one image every 12 s) were acquired using gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) (10 or 100 mumol/kg) to study perfusion and concentrating ability in normal rabbit kidneys and in kidneys with HgCl2-induced acute tubular necrosis (ATN). In normal rabbits receiving 100 mumol Gd-DTPA/kg a concentric region of decreased MR signal was observed. In sequential images the dark ring pattern migrated centripetally through the kidney moving from the corticomedullary junction to the inner medulla. The decrease in MR signal intensity occurred as a consequence of T2 relaxation (magnetic susceptibility) due to high concentration of Gd-DTPA within the tubules. This suggests that the dark ring pattern may serve as a qualitative feature indicative of the ability of the kidneys to concentrate. With the onset of HgCl2-induced ATN the pattern of enhancement due to Gd-DTPA administration changed markedly. Although the kidneys with ATN did continue to be perfused, the concentric dark ring pattern seen in normal kidneys receiving 100 mumol Gd-DTPA/kg was not observed. These results suggest that Gd-DTPA and fast imaging MR may provide a method of assessing perfusion and concentrating ability within the healthy or diseased kidney.
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PMID:Acute tubular necrosis: use of gadolinium-DTPA and fast MR imaging to evaluate renal function in the rabbit. 357 94

Renal transplant radionuclide studies, using DTPA, were analysed to produce flow and transit time measurements in both the initial arterial phase, and the later glomerular phase. Results are presented for transplanted kidneys which are normal, infarcted, obstructed, or suffering from rejection or acute tubular necrosis. Sequential studies of the vascular flow and transit time indices showed considerable promise in the detection of acute rejection, even in the presence of acute tubular necrosis. Of the six numerical indices to demonstrate acute rejection, five had accuracies of 74% or more, and all three of the indices which compared a study with a previous one had accuracies of 83% or more.
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PMID:A comprehensive analysis of renal DTPA studies. II. Renal transplant evaluation. 391 35

One hundred forty-nine standardized K/A rations (renal bolus ascending slope: aortic bolus ascending slope) were performed on 33 post-transplant patients with acute or chronic rejection, obstruction, acute tubular necrosis, infection or acute hypertension after rapid intravenous injection of Tc-99m DTPA. The correlation of creatinine clearance versus the K/A ratio for 123 pairs of data performed on the same day was poor (r = 0.37), but the correlation was greatly improved (r = 0.72) when K/A ratio maxima or minima were compared with corresponding creatinine clearances performed during a nonrejection period, or acute rejection episode, respectively. Seventeen acute rejection episodes resulted in a 20% or greater decrease in the K/A ratio 16 times, but were observed as a change in the serial perfusion phase scintiphotos only five times, or in the function phase scintiphotos only six times. Of 27 significant decreases in K/A ratios, 22 were due to acute rejection, two to obstruction, one to infection, one to acute hypertension, and one was unexplained. Thus the K/A ratio is a sensitive but not specific index for following pathological changes in the renal allograft.
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PMID:Application of the kidney to aortic blood flow index to renal transplants. 635 51

The effectiveness of Computerized Renal Angioscintigraphy with 99m-Tc-DTPA and Ultrasound in the differential diagnosis of complications after kidney transplant was evaluated. 13 patients were studied; 6 with a normal graft, 2 with acute tubular necrosis and 5 with an acute rejection episode. Technectium scan and ultrasound diagnosis were in good agreement with clinical assessment resulting in 1.00 and 0.92 sensitivity respectively. The most valuable features of radionuclide and ultrasound techniques are: noninvasiveness, simplicity, rapidity and reproducibility. The selection of a course of treatment could be usefully helped or supported by data obtained from scintigraphy and ultrasound.
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PMID:Computerized angioscintigraphy and ultrasound imaging in the management of renal transplants. 637 28

The ability to detect renal rejection sonographically was studied in 42 pediatric renal transplant patients over a 33-month period. Sonography was not helpful in detecting rejection when the donor was less than five years of age. When the donor was over five years of age, a combination of sonographic findings allowed detection of rejection with a greater specificity than has been reported previously. The combination of three or more of the sonographic findings (increased renal volume 30% over the baseline value; enlarged, broadened, rectangular medullary pyramids [rays]; a reduction or absence of the central sinus echoes, and altered echogenicity in the renal parenchyma) indicated rejection with 97% specificity and 58% sensitivity. Radionuclide imaging with Tc-99m DTPA gave approximately the same sensitivity (60%) but was less specific (88%). By excluding rejection with the absence of the sonographic findings, it was possible to suggest acute tubular necrosis in some patients. It was also possible to detect the complications of renal transplantation, but sonography did not detect small ruptures of the kidney as a part of the rejection phenomenon.
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PMID:Renal transplant rejection: sonographic evaluation in children. 638 88

A study of the magnetic resonance imaging (MRI) appearances of the kidneys in six normal volunteers and 52 patients is reported. Corticomedullary differentiation was seen with the inversion-recovery (IR 1400/400) sequence in the normal volunteers and in patients with functioning transplanted kidneys and acute tubular necrosis. Partial or total loss of corticomedullary differentiation was seen in glomerulonephritis, acute and chronic renal failure, renal artery stenosis, and transplant rejection. The T1 of the kidneys was increased in glomerulonephritis with nephrotic syndrome, but the T1 was within the normal range for renal medulla in glomerulonephritis without nephrotic syndrome, renal artery stenosis, and chronic renal failure. A large staghorn calculus was demonstrated with MRI, but small calculi were not seen. Fluid within the hydronephrosis, simple renal cysts, and polycystic kidneys displayed very low signal intensity and long T1 values. Evidence of recent hemorrhage into cysts was seen in polycystic kidneys. Tumors displayed varied appearances. Hypernephromas were shown to be hypo- or hyperintense with the renal medulla on the IR 1400/400 sequence. After intravenous injection of gadolinium-DTPA, there was marked decrease in the tumor T1.
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PMID:Magnetic resonance imaging of the kidneys. 638 80

In order to evaluate the usefulness of radionuclide renal studies in differentiating acute tubular necrosis from other causes of decreased renal clearance (e.g., rejection) in renal transplant patients, we assumed that acute tubular necrosis would be common during the first 4 days after cadaveric transplantation (group 1) and uncommon 3 weeks or longer after transplantation (group 2). There were 38 renal studies in 34 patients in group 1 and 62 studies in 27 patients in group 2. Each renal study consisted of both a technetium-99m-DTPA and an iodine-131-hippuran study. Perfusion, clearance, and transit time in the 99mTc-DTPA study, and clearance and transit time in the 131I-hippuran study were visually graded on a 5 point scale without knowledge of the time of study or clinical diagnosis. There were 19 studies in group 1 and 25 studies in group 2 with clearance decreased two or more gradations. Eleven 99mTc-DTPA studies had perfusion 2 or more gradations better than clearance; all 11 were in group 1 (p less than 0.01). Other dissociations within the 99mTc-DTPA and 131I-hippuran studies, or between them, did not distinguish the two groups. Data support the hypothesis that decreased clearance with relatively well preserved perfusion in 99mTc-DTPA studies is common in acute tubular necrosis and uncommon in other causes of decreased renal clearance.
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PMID:99mTc-DTPA renal studies for acute tubular necrosis: specificity of dissociation between perfusion and clearance. 678 Dec 42

In 60 patients with a kidney transplant 86 perfusion studies with 99mTc-DTPA were performed during the early postoperative period. Correlative data and clinical differentiation were obtained by isotope nephrograms, laboratory values and clinical presentation. In addition to evaluation of scintiphotos, time-activity curves were derived from the transplant and evaluated quantitatively, obtaining a perfusion ratio by a computer program. A ratio of greater than 0.80 was found to be normal. In 20 patients with acute rejection, the ratio was decreased. In 13 patients with acute tubular necrosis, the perfusion ratio was between 0.39 and 0.65, decreasing further during an added rejection crisis. Follow-up examinations confirmed rejection through a decrease of the perfusion ratio (mean difference 0.44; p less than 0.025). In 9 cases, successful rejection therapy was documented by an increase (mean difference 0.29; p less than 0.005). In addition to quantitative evaluation, visual analysis revealed acute occlusion of the renal artery, renal infarction, urinoma, ureteral stenosis or necrosis. Quantitative scintigraphy with 99mTc-DTPA broadened the methods of describing kidney transplant function. Its quantitative evaluation enables the definition of acute rejection and its differentiation from acute tubular necrosis combined with acute rejection in the early postoperative period. Since the method recognizes morphological alterations as well, it usefully complements isotope nephrography.
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PMID:[Evaluation of renal transplant function by 99mTc-DTPA dynamic imaging (author's transl)]. 702 21


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