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Query: UMLS:C0022672 (acute tubular necrosis)
 2,175 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of transient renal ischemia on renal concentration and distribution of 99mTc-HEDP, 99mTc-DMSA, and 99mTc-DTPA was compared in rabbits with acute tubular necrosis. Scintigrams were obtained after injection in normal rabbits or ones with unilateral or bilateral ischemia. 99mTc-HEDP concentration in ischemic tissue was 8 to 18 times normal 1--4 hours after injection, and the resulting images delineated the morphological changes in the ischemic kidneys more accurately than those obtained with DMSA or DTPA. Calcium concentration in the ischemic kidneys increased sixfold. 99mTc-HEDP may be useful in evaluation of renal failure secondary to tubular injury.
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PMID:Renal hyperconcentration of 99mTc-HEDP in experimental acute tubular necrosis. 22 Jun 70

Serial dynamic studies with 99mTc-DTPA are a useful method of monitoring renal transplants. Radionuclide images obtained within 24 hours after surgery and at regular intervals thereafter can identify pathological conditions. The decline or absence of perfusion, coupled with the elapsed time following surgery, can be used to differentiate vascular occlusion or hyperacute rejection from acute rejection, acute tubular necrosis, or accelerated or chronic rejection. 99mTc-pyrophosphate can be used to simultaneously evaluate transplant function and locate possible aseptic necrosis of bone. Both studies are noninvasive and have been performed safely on numerous occasions over a period of several years.
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PMID:The temporal and pathological significance of perfusion failure following renal transplantation. 23 48

We have performed 955 studies on 152 patients with 167 renal transplants. Images were recorded following bolus injection of 12-15 mCi Tc-99m DTPA (Sn). The data were stored on a computer and analyzed by generation of region-of-interest curves from (a) the iliac artery distal to the transplant, (b) the kidney, and (c) a background area. A perfusion index was adopted: formula see text. In 276 studies the patient clearly had acute tubular necrosis (ATN), rejection, or a normal kidney on retrospective analysis. The normal perfusion index has a value below 150, and it increases with falling perfusion, such as is seen in rejection and in renal-artery stenosis. The use of this index in addition to sequential images and changes in the region-of-interest curves usually allows separation of rejection from ATN and, particularly, rejection from normals. When serial studies are performed, the separation of rejecting from nonrejecting transplants is excellent, although renal-artery stenosis may cause similar changes in perfusion.
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PMID:Dynamic renal transplant imaging with Tc-99m DTPA (Sn) supplemented by a transplant perfusion index in the management of renal transplants. 35 87

Three hundred and fifty-eight renal imaging studies with quantitation of renal perfusion were performed following injection of 99Tcm-DTPA in 22 children aged 6--15 years with renal transplants. In 58 of 62 scans performed at the onset of a rejection episode, renal perfusion was decreased. This was the only feature of rejection in 6 episodes, in 5 of which the patient was oliguric due to post-operative acute tubular necrosis. In 4 episodes perfusion fell, but antirejection treatment was not given as a repeat scan was normal. On 18 occasions the plasma creatinine concentration (Pc) rose, but the scan was unchanged; no treatment was given and repeat Pc was normal. Three patients had a ureteric obstruction and 2 patients a lymphocoele detected from the images. There was no morbidity. Sequential renal scintigraphy was valuable in the early diagnosis of rejection and in the avoidance of unnecessary therapy.
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PMID:Serial quantitative imaging with 99Tcm-DTPA in pediatric renal transplantation. 38 5

The usefulness of the renal scan in diagnosing technical complications in the transplant patient is well established. However, the ability of the renal scan to differentiate between acute rejection and acute tubular necrosis has remained uncertain. We have evaluated the effectiveness of the 99mTc DTPA computer-derived time-activity curve of renal cortical perfusion, as well as data obtained from scintillation camera images, in making such diagnoses. Fifteen patients with a clinical diagnosis of either acute rejection or acute tubular necrosis, or both, were studied retrospectively. Technetium scan diagnoses did not agree with the clinical assessment in nine of the patients. Thus selection of a course of treatment should not be based on data obtained from the scan alone.
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PMID:Differentiation between renal allograft rejection and acute tubular necrosis by renal scan. 40 93

In order to refine the diagnostic possibilities of the radionuclide renal study in transplanted patients and to compensate for the nonspecificity of the 131I-hippuran study in some situation, 99mTc-DTPA WAS USED SIMULTANEOUSLY FOR IMAGING AND TIME-ACTIVITY CURVES. For these curves to be significant, appropriate background subtraction had to be made with a simple computer-processing method. The results obtained have shown that it is possible to distinguish marked acute tubular necrosis from milder degrees, thus affording a prognostic index in the immediate postoperative period, when the hippuran data are often nonspecific. Further, the diagnosis and follow-up of acute rejection episodes can be improved by the DTPA processed curves. Although these curves when examined individually do not show a specific pattern for rejection, they may reveal striking evolutionary changes when compared to the previous studies, even when the hippuran curves are unchanged. The physiologic basis for the differences between the two time-activity curves may be related to the differential handling of the two radiopharmaceuticals by the kidney.
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PMID:Computer processed 99mTc-DTPA studies of renal allotransplants. 110 55

Color Doppler sonography (CDS) detects changes in renal blood flow that may be useful in evaluating renal transplant dysfunction (RTD). To assess the performance of CDS as a clinical test, we reviewed results from 223 CDS measurements in 130 renal transplant recipients during a 26 month period. Spectral wave forms were characterized by pulsatility index (PI) (maximum frequency shift minus minimum frequency shift divided by mean frequency shift). In 27 individuals with stable renal function, mean PI was 1.80 +/- 0.23 (S.D.). Abnormal PI were subsequently defined as greater than two S.D. more than the mean (PI greater than or equal to 2.3). CDS performed during the early post-transplant period (n = 91) could not differentiate acute tubular necrosis (ATN), obstruction and rejection. Abnormal studies were seen in 35 of 46 instances of ATN and in three of obstruction. In 132 studies done after the postoperative period, CDS became abnormal during rejection episodes in only 45 of 71 instances (sensitivity rate of 63 per cent). When abnormal, CDS was highly suggestive of rejection, however (45 of 49, 92 per cent specificity). Cyclosporine toxicity was not associated with abnormal pulsatility (zero of seven). In 68 instances, CDS and conventional 99mTc DTPA renogram flow studies were performed together within 24 hours. CDS was more sensitive in detecting rejection but the difference did not reach statistical significance (25 of 36 versus 17 of 36). The major advantage of CDS over conventional radionuclide imaging relates to its shorter examination time, lower cost and portable capabilities. CDS will probably become the roentgenologic imaging modality of choice in renal transplantation.
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PMID:Evaluation of renal transplant dysfunction using color Doppler sonography. 192 97

This study was undertaken to assess the significance of diastolic flow reversal seen on duplex Doppler sonograms of patients with renal transplant dysfunction. Earlier studies have evaluated the causes of increased vascular resistance in renal transplants. None, however, have investigated specifically the subset of patients in whom impedance in the renal microcirculation has increased to the degree that retrograde arterial flow is present. In our series, 533 consecutive scans in 270 patients were reviewed. The patients were referred for evaluation of renal transplant dysfunction during a 25-month period. Doppler samples were obtained from main, segmental, and, when possible, arcuate arteries. An episode of reversed diastolic flow was identified in nine patients. Correlation was made with clinical, laboratory, histologic (biopsy in six patients, nephrectomy in three patients), and imaging studies (DTPA scintigraphy in seven patients, angiography in one patient). On the basis of histologic and nephrectomy results, we determined that among the nine patients, four had acute tubular necrosis, three had acute rejection, and two had renal vein thrombosis. One of these patients had both severe rejection and renal vein thrombosis. One additional patient had neither biopsy nor nephrectomy and was not included in the diagnostic groups listed here. Our study suggests that reversed diastolic flow is not specific for either acute rejection or acute tubular necrosis. Reversal of diastolic flow, however, is a poor prognostic sign; nephrectomy was imminent in three of the nine patients. Furthermore, two (22%) patients had renal vein thrombosis, whereas renal vein thrombosis was not found in any of the 261 patients without reversed diastolic flow. Duplex Doppler examinations with reversed diastolic flow should suggest renal vein thrombosis.
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PMID:Duplex Doppler sonography in renal allografts: the significance of reversed flow in diastole. 211 55

Tc-99m DTPA scintigraphic findings in patients with postoperative complications of renal transplantation were presented. In acute tubular necrosis, excretion of the tracer was not observed though its perfusion was preserved. In acute rejection, perfusion was reversibly disturbed. In chronic rejection, perfusion was irreversibly disturbed. In renal infarction, multiple defects were observed. In renal vein thrombosis, similar pattern to acute tubular necrosis was found but RI venography was helpful. In lymphocele, perirenal photon deficiency was observed. In renal artery thrombosis, absence of the perfusion and total photon deficient were noted. Tc-99m DTPA renal scintigraphy is useful for diagnosis and follow up of the complications of transplanted kidneys.
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PMID:[Tc-99m DTPA scintigraphic findings in patients with postoperative complications of renal transplantation]. 268 14

We developed an easily implemented clinical procedure for quantitative perfusion measurements in transplanted kidneys using intravenously administered [99mTc]DTPA and the tracer fractionation technique. F = Ak(T)/0 integral of T [Aa(t)/Va] dt, where F = renal blood flow, Ak(T) = DTPA activity in kidney at time = T, Va = ultrasonographically measured femoral artery segment volume, T = time postinjection of F determination, and Aa(t) = time course of DTPA activity in femoral artery segment. The technique was applied to a group of 80 studies in 35 patients in whom an independent clinical determination of transplant function was available. Blood flow (units of ml/min) measured 439 +/- 83 in normally functioning transplants, 248 +/- 63 in transplants with acute tubular necrosis, 128 +/- 62 in transplants with rejection, and 284 +/- 97 in transplants with cyclosporine toxicity. These preliminary results indicate potential usefulness of this method in the evaluation of renal function following transplant surgery.
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PMID:Quantitative measurement of renal perfusion following transplant surgery. 304 58


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