DMSA Uptake Research Articles

Somatostatin-receptor imaging of medullary thyroid carcinoma.

In-111 pentetreotide scintigraphy of 10 patients with residual or metastatic medullary thyroid carcinoma is described. Six patients had sporadic tumor and 4 had MEN IIB. Foci of increased tracer uptake were observed in 9 patients: in the thyroid bed (4 patients), the mediastinum (3 patients.), the shoulder area and left lower abdomen (1 patient), and the left upper abdomen (1 patient). The 10th patient had no abnormal uptake. CT confirmed 2 mediastinal lesions and 2 out of 3 thyroid masses, but did not detect the thyroid remnants or the lesions in the shoulder area and abdomen. Lung lesions < or = 1 cm in diameter and ill-defined liver foci (2 patients) were seen on CT, but not on scintigraphy. Small liver metastases not demonstrated on CT or on scintigraphy were identified at surgery in a MEN IIB patient. Elevated urinary epinephrine was found in 2 out of 4 MEN IIB patients. In one, tracer uptake in the left adrenal corresponded to a mass on CT, to pathological uptake of MIBG and DMSA, and to a tumor removed at surgery. The second patient had peritoneal spread of malignant pheochromocytoma (at surgery), but negative CT and only a single focus in the left lower abdomen on scintigraphy. Somatostatin-receptor imaging is useful for the detection of residual and recurrent medullary thyroid carcinoma, and may identify pheochromocytoma in MEN IIB patients.

Effect of Percutaneous Transluminal Renal Angioplasty on Absolute Split Renal Function in Patients with Renovascular Hypertension. Influence of Age and Other Parameters

Tc99m-dimercaptosuccinic acid renal uptake (DMSA uptake) was examined to assess the changes in split renal function following percutaneous transluminal renal angioplasty (PTRA) in 9 patients with a total of 12 renal artery stenoses and renovascular hypertension (RVH). The results were studied with respect to age, degree of renal artery stenosis, and renal vein renin ratio (RVRR) before PTRA. Although the degree of renal artery stenosis, systolic blood pressure, and peripheral blood plasma renin activity were improved 3 months after PTRA, neither the DMSA uptake of the affected kidneys nor that of the contralateral kidneys improved. Although restenosis occurred during the long follow-up period in one patient, DMSA uptake did not change in parallel with the degree of stenosis or RVRR. The degree of improvement in DMSA uptake, blood pressure, and plasma renin activity after PTRA in patients aged under 70 years was significantly higher than that in patients 70 years or older. Good improvement of renal function was attained in a 4-year-old boy, despite the fact that split renal function prior to PTRA was so poor that nephrectomy had been considered instead of PTRA. These results suggest that several factors before PTRA, such as DMSA uptake, degree of renal artery stenosis, and RVRR, are not absolutely predictive of results after PTRA, and that the effect of PTRA on blood pressure and renal function is greater in younger patients.

Renal function of contralateral kidney after total or partial removal of kidney with ectopic ureter

The effects of partial or total removal of the kidney with ectopic ureter on the contralateral kidney were evaluated using DMSA renal uptake rate on 8 patients. After partial nephrectomy on 6 cases, the affected residual kidneys showed significant decrease in DMSA renal uptake rate in 2 cases in which the extirpated kidneys had normal renal tissue in part but did not show significant change in DMSA uptake rate in 4 cases in which the extirpated kidneys were dominated mainly with dysplasia. Post-operative increase in DMSA uptake rate of the contralateral kidneys were significant in 3 of 4 patients who had the operation before they became 2 years old. In 2 of these 3 cases, pre-operative scintigram showed extremely low rate of DMSA renal uptake. Four cases aged 2 years old and over did not show post-operative increase in the uptake rate. As we have previously reported on the cases with hydronephrosis, these results suggest that 1) existence of obstruction caused by ectopic ureter inhibit the development of the contralateral kidney and 2) the growth of the kidney can resume the release of that obstruction, if the release is made while the kidneys are still in developing stage.

Effect of extracorporeal piezoelectric lithotripsy shock waves on renal function measured by Tc-99m-DMSA using SPECT.

Extracorporeal shock-wave lithotripsy has altered the therapeutic approach to urinary stone disease. Recently, a method was developed in which shock-wave generation is obtained piezoelectrically. To evaluate the effect of extracorporeal piezoelectric lithotripsy (EPL) on renal function, 20 patients were studied prior to and after EPL of renal calculi. Renal cortical function was evaluated by using a previously described and validated quantitative single photon emission computerized tomography (SPECT) method to measure individual absolute uptake of technetium-99m dimercaptosuccinic acid (Tc-99m-DMSA). Twenty kidneys were treated, and the 19 contralateral kidneys were without stone disease (1 patient had a single kidney). The absolute kidney uptake of Tc-DMSA in the normal kidneys was 21.4% +/- 6.2% before and 22.2% +/- 6.4% after EPL. For the treated kidneys the absolute update was 16.8% +/- 5.3% and 16.8% +/- 4.7% before and after, respectively. There was no statistical significant difference between pre- and post-treatment values. The absolute kidney uptake was significantly lower (p less than 0.01) in the treated than in the normal kidneys. This study indicates that the EPL procedure did not cause any damage to cortical function detectable by the DMSA uptake.

False-Positive Tc-99m Pentavalent DMSA Uptake in the Imaging of Medullary Carcinoma of the Thyroid

False-Positive Tc-99m Pentavalent DMSA Uptake in the Imaging of Medullary Carcinoma of the Thyroid

99mTechnetium dimercaptosuccinic acid scintigraphy in the diagnosis of acute pyelonephritis in rats

The use of 99mtechnetium dimercaptosuccinic acid (99mTc-DMSA) scintigraphy for the early diagnosis of pyelonephritis has been evaluated in a study performed on adolescent female Sprague-Dawley rats exposed to an ascending Escherichia coli infection. The rats were studied with DMSA scintigraphy either before and 5 days after the infection or 5 and 28 days after the infection. One group of rats received anti-microbial treatment during days 6-11. After the last DMSA scintigraphy the rats were sacrificed and the kidneys prepared for light microscopy study. Kidney morphology was normal and DMSA uptake was high and homogeneous in all control rats. The majority of the rats exposed to E. coli developed inflammatory changes, on light microscopy which extended to various degrees in the renal parenchyma. Five days after the infection the DMSA uptake was consistently reduced, if the inflammatory lesion on light microscopy involved more than 15% of the renal cortex. Twenty-eight days after infection the inflammatory changes were less extensive than at 5 days. The DMSA uptake had usually improved. At this time, however, areas of decreased DMSA uptake could be detected even if the light microscopy changes involved less than 15% of the parenchyma. Microscopical lesions were less frequent and less extensive in the treated than in the untreated rats. The complete return to normal of previously abnormal DMSA uptake was only observed in treated rats. In a few untreated rats cortical scars had formed by day 28. The scars appeared in areas with decreased DMSA uptake at 5 days.(ABSTRACT TRUNCATED AT 250 WORDS)

&lt;sup&gt;99m&lt;/sup&gt;Tc-DMSA腎シンチグラフィによるPNLの腎機能に及ぼす影響の検討

99mTc-DMSA renal scintigraphy was carried out in 54 patients with unilateral renal stones before and after PNL. Four to 8 weeks after PNL the DMSA renal uptake significantly decreased to 17.2 +/- 6.0% from 18.2 +/- 6.7% before PNL. DMSA renal uptake did not change in the contralateral side. Since in some patients changes in the DMSA renal uptake of 5-7% were observed after PNL not only in the PNL side but also in the contralateral side, the renal function was assessed by the formula: DMSA renal uptake in the PNL side/DMSA renal uptake in the contralateral side, and the change of this ratio was evaluated in 44 patients, in whom the renal DMSA uptake in the PNL side was less than two times that in the contralateral side. The DMSA renal uptake ratio decreased to 95.6 +/- 8.7% from the base line 4-8 weeks after PNL. This change was statistically significant. Some functional risks such as massive bleeding with PNL, the fever after PNL and the number of nephrostomy tract did not affect the decrease in the renal function. In 29 patients in whom renal function was reevaluated one year after PNL, the DMSA renal uptake ratio significantly decreased to 94.2 +/- 9.6% from the base line 4-8 weeks after PNL. But the ratio significantly improved to 99.6 +/- 11.6% about one year after PNL. In two patients with a cold area on the renal image, the renal function of the operated side still remained at about 80% levels from the base line even one year after PNL.(ABSTRACT TRUNCATED AT 250 WORDS)

幼少児膀胱尿管逆流症例における腎機能評価

The function of 99 refluxing kidneys of 61 children up to two years old at the time of diagnosis was evaluated by 99mTc-DMSA renoscintigraphy, urinary beta 2-microglobulin (beta 2-MG), alpha 1-microglobulin (alpha 1-MG) and N-acetyl-beta-D-glucosamidase (NAG). High grade reflex (grade IV, V) was found in 45% of the cases. 76%, 51% and 92% of the cases showed abnormally high value of urinary beta 2-MG, alpha 1-MG and NAG, respectively. These results indicate that they have already had tubular dysfunction at the time of diagnosis. DMSA renoscintigraphy of 82 refluxing kidneys of 49 children was performed. Of these, 48% had renal scar and 28% had serious renal dysfunction [DMSA uptake rate less than 18%]. 10-20% of low grade VUR had less than 18% DMSA uptake rate. Two patterns were noticed in the group in which urinary beta 2-MG ranged 0.33-1.0. One was characterized by good bilateral renal function with slight tubular damage and the other serious renal dysfunction with fixed tubular damage. No remarkable recovery of the renal function was noticed after antireflux operation in the second pattern cases. In many cases, in which urinary beta 2-MG was more than 1.0, improvement of DMSA uptake rate was noticed after antireflux operation.

Effect of Unilateral Vesicoureteric Reflux on Renal Growth and the Uptake of 99mTc DMSA by the Kidney. An Experimental Study in the Minipig

The influence of unilateral vesicoureteric reflux (VUR) on renal growth and the uptake of 99mTc DMSA by the kidney has been investigated in a 2-kidney model in the growing minipig over a period of approximately 5 months. Animals with reflux in association with low voiding pressures and normal bladder function (n = 5), as well as those with raised voiding pressures and abnormal bladder function (n = 7), were investigated with appropriate non-refluxing controls (n = 12). Urinary infection and renal scarring were avoided since these factors may affect kidney function and growth independently. Statistical tests of difference failed to demonstrate any effect of VUR on renal growth or renal uptake of 99mTc DMSA even in the presence of elevated voiding pressures and abnormal detrusor function.

Investigation of factors affecting the progression of polycystic kidney disease and effects of percutaneous reduction of cystic size

Factors affecting the progression of autosomal dominant adult type polycystic kidney disease were analysed in 27 cases. The patients ages ranged from 10 to 74 (mean 44) years old and the serum creatinine values were within the normal limits except two cases, in which the values were 2.4 mg/dl and 2.1. They were followed for from 2 years to 12 years (mean 5.6 years). During the followup period, 6 cases showed elevation of the serum creatinine values and hemodialysis was necessary in 4 cases. There was a tendency of higher morbidity rate of hypertension, proteinuria, hematuria and pyuria in the cases with decreased renal function. These factors may have participated in the progression of polycystic kidney disease. Cystic fluid analysis was performed by percutaneous puncture of more than hundred cysts in 27 cases. The results showed that the cystic fluid components of most cysts of the well functioning kidneys were similar to those of serum values: so-called proximal cysts. On the other hand, in the cases with decreased renal function, there were many cysts with lower sodium concentration and higher creatinine values: so-called distal cysts. The results suggest that the existence of so-called distal cysts may indicate poorer prognosis. DMSA renoscintigraphy was useful for followup polycystic kidney patients because of the uptake of the radionuclide was decreased before rising the serum creatinine value. In 6 cases, the cysts were instilled with 95% ethanol. Followup ultrasonography and DMSA renoscintigraphy revealed a marked reduction of the cystic size and an improvement of DMSA uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Relative and absolute 99Tcm-DMSA uptake measurements in normal and obstructed kidneys.

Relative and absolute 99Tcm-DMSA uptake measurements were carried out on 25 adult patients among whom there were 23 normal and 25 malfunctioning kidneys. Data were collected at 3 and 6 h post intravenous tracer injection. Four methods of calculating absolute uptake were investigated and evaluated. These were based on: (1) posterior view and measured kidney depth; (2) posterior view and Raynauld's depth; (3) geometric mean assuming kidney thickness is small enough not to introduce self attenuation of counts in the kidney itself; (4) geometric mean taking kidney thickness into account. Whilst (1) and (2) were found to overestimate and underestimate renal uptake by up to 5 and 14%, respectively, (3) and (4) were found to be more accurate and comparable. The measurement of relative DMSA uptake (right to left) showed no change between the 1 and 6 h measurements for both obstructed and non-obstructed kidneys. Based on the results from method 4, the absolute renal DMSA uptake had a mean value of 25.4%, S.D. 8.9% and 30.0%, S.D. 9.2% at 3 and 6 h, respectively, for normal/non obstructed kidneys. For obstructed kidneys (responding to frusemide), the mean uptake was 23.0%, S.D. 7.2 and 25.6%, S.D. 6.7% at 3 and 6 h, respectively. For obstructed kidneys not responding to frusemide, the mean uptake was 16.8%, S.D. 3.9 and 20.6%, S.D. 4.8% at 3 and 6 h, respectively. No correlation was found between absolute DMSA uptake and degree of renal obstruction.

Changes in renal function during physical and mental effort.

Aim of the study was to evaluate the renal responses to physical and mental effort in essential hypertension by means of a non-invasive radioisotopic method. Renal uptake rate of Tc99m-DMSA was evaluated in 10 subjects. Starting from 5 to 15 minutes after dose injection counts over the kidney region were acquired by means of a gamma-camera time-activity curves were obtained for each kidney. In non-stimulated patients DMSA uptake rate increased regularly; in the remaining cases both isometric exercise and mental effort induced an abrupt reduction of the uptake rate which increased again after the end of the test. Although the relation of DMSA uptake rate to renal function is not yet fully understood, we tentatively interpret these results as indicating blood flow reductions during these stressful conditions.

Anomalous DMSA uptake in unilateral renal artery occlusion

Anomalous DMSA uptake in unilateral renal artery occlusion

Technetium-99m DMSA imaging and the obstructed kidney.

Although several authors have claimed that the function of an obstructed kidney could be overestimated on Tc-99m DMSA imaging, the clinical importance of such an overestimation has not been well documented. Partial obstruction of one ureter was created in a rat, and a relative Tc-99m DMSA uptake was obtained 4 hours after intravenous injection. By puncture of the isolated obstructed kidney, it was shown that the function of that kidney was overestimated by at least 17%.

Technetium-99m DMSA Abnormal Uptake by Metastatic Lesion of a Renal Cell Carcinoma

A case of renal cell carcinoma, clear cell type, with bone metastasis that took up Tc-99m DMSA in the presence of normal renal function is presented. The primary renal tumor, however, did not definitely show Tc-99m DMSA accumulation. The reason is probably that Tc-99m DMSA uptake by tumor cells is much less prominent than uptake by normal tubular cells. Our finding suggests that Tc-99m DMSA may have an affinity for some types of adenocarcinomas. The details of the tumor affinity mechanism of this agent still must be studied.

Quantitation of renal function with 99Tcm-DMSA. A comparison with creatinine clearance in children with single kidney.

To study the accuracy of renal function quantification with 99Tcm-DMSA we compared DMSA renal uptake and creatinine clearance in 16 cases of children with single kidney. The age of the patients ranged from two months to fourteen years. Creatinine clearance was normalized to 1.73 m2. DMSA uptake was measured 7 h after intravenous injection. Background subtraction was used and soft tissue attenuation was taken into account. The uptake was normalized in percentage of the injected activity. A significant correlation was found between creatinine clearance and DMSA uptake (rt = 0.866, p less than 0.01). Normal creatinine clearance range in children (80 to 120 ml min-1/1.73 m2) allowed determination of normal uptake range (36 to 60%). This study indicates that in case of asymmetrical renal impairment renal uptake will reflect split renal creatinine clearance. Since the former is much easier to measure, DMSA should play an important role in the evaluation of differential renal function.

Quantitation of Renal Function With Static Imaging Agents

DMSA is an excellent static imaging agent. Approximately 50% of the injected dose remains bound to the cortical tubules of the kidney up to 24 hr after injection. During this time, 30% of the dose is excreted in the urine, background activity drops significantly, and kidney-to-background ratio is enhanced markedly. A 5 mCi dose is adequate for static imaging even out to 24 hr and the 5 mCi dose can be reduced for 1–4 hr post injection images. Patients should be adequately hydrated prior to a DMSA study since adequate hydration may enhance the excretion of DMSA, decrease background activity, improve the kidney-to-background ratio, and lower the radiation dose to the patient. A number of studies have shown that the relative uptake of DMSA correlates well with the relative ERPF and GFR in patients with both normal and asymmetrically functioning kidneys however, there are only a limited number of comparison studies in patients with severely compromised renal function. In this group of patients, comparison and validation studies are complicated by the fact that measuring the relative renal uptake of hippurate or DTPA during the first 1–3 min post-injection can be statistically less accuarate than determining the relative uptake of DMSA. A few investigators have reported DMSA scanning may be misleading in patients with obstruction due to retention of DMSA in the renal pelvis. This conclusion is based on a discrepancy in the relative renal function determined using DMSA and 131 I-hippurate or DTPA. Since obstructed kidneys generally have diminished function, this discrepancy may be related to the problem of region of interest assignment and background substraction during the first 1–3 min after hippurate or DTPA injection. While other investigators have not observed obstruction to be a problem, it is probably safer to confirm DMSA results in patients with obstruction with an additional study using hippurate or DTPA until more comparison data become available. After reconstitution with 99m Tc pertechnetate, the DMSA preparation is quite sensitive to oxidation and air should not be introduced into the reaction vial. If more than one dose is to be obtained from a single vial, the two or more doses should be drawn immediately after each other and administered as soon as possible. Oxidation will degrade the DMSA complex, decrease uptake in the kidney and increase liver background activity. It also is important to note that acidification of the urine in rats with ammonium chloride doubled the liver uptake of DMSA and decreased the renal uptake by 50%. Acidification of the urine in patients may also alter the biodistribution and, in theory, may also alter the relative distribution of DMSA between asymmetrically functioning kidneys. These possibilities need to be further evaluated. Finally, since a number of variables can affect the total renal accumulation of DMSA, DMSA should not be quantitated as an absolute index of renal function unless it is done by experienced investigators under carefully controlled conditions.

Evaluation of 99mTc-Dimercaptosuccinic Acid Renal Uptake as an Index of Individual Kidney Function after Acute Ureteral Obstruction and Desobstruction

The evolution of the 99mTc-dimercaptosuccinic acid (DMSA) renal uptake is followed after ligation of the right ureter in rats. The DMSA uptake falls rapidly from 35% before ligation to 13% after 24 h, and decreases further to 1.5% after 31 days. The ligated ureter was desobstructed after 10, 17, 24 and 31 days, respectively, DMSA uptake was controlled 4, 11 and 18 days after desobstruction. In the first group, deobstruction after 10 days, the DMSA uptake rose from 7 to 15%, while in the fourth group it rose from 1.5 to 2%. It is concluded that DMSA uptake provides a reliable index for renal function after acute urinary tract obstruction in rats. If the DMSA uptake has fallen below 4% very little renal function can be expected to be regained, whereas above 4% the function can improve considerably.

Quantitation of renal function with static imaging agents

DMSA is an excellent static imaging agent. Approximately 50% of the injected dose remains bound to the cortical tubules of the kidney up to 24 hr after injection. During this time, 30% of the dose is excreted in the urine, background activity drops significantly, and kidney-to-background ratio is enhanced markedly. A 5 mCi dose is adequate for static imaging even out to 24 hr and the 5 mCi dose can be reduced for 1–4 hr post injection images. Patients should be adequately hydrated prior to a DMSA study since adequate hydration may enhance the excretion of DMSA, decrease background activity, improve the kidney-to-background ratio, and lower the radiation dose to the patient. A number of studies have shown that the relative uptake of DMSA correlates well with the relative ERPF and GFR in patients with both normal and asymmetrically functioning kidneys however, there are only a limited number of comparison studies in patients with severely compromised renal function. In this group of patients, comparison and validation studies are complicated by the fact that measuring the relative renal uptake of hippurate or DTPA during the first 1–3 min post-injection can be statistically less accuarate than determining the relative uptake of DMSA. A few investigators have reported DMSA scanning may be misleading in patients with obstruction due to retention of DMSA in the renal pelvis. This conclusion is based on a discrepancy in the relative renal function determined using DMSA and 131 I-hippurate or DTPA. Since obstructed kidneys generally have diminished function, this discrepancy may be related to the problem of region of interest assignment and background substraction during the first 1–3 min after hippurate or DTPA injection. While other investigators have not observed obstruction to be a problem, it is probably safer to confirm DMSA results in patients with obstruction with an additional study using hippurate or DTPA until more comparison data become available. After reconstitution with 99m Tc pertechnetate, the DMSA preparation is quite sensitive to oxidation and air should not be introduced into the reaction vial. If more than one dose is to be obtained from a single vial, the two or more doses should be drawn immediately after each other and administered as soon as possible. Oxidation will degrade the DMSA complex, decrease uptake in the kidney and increase liver background activity. It also is important to note that acidification of the urine in rats with ammonium chloride doubled the liver uptake of DMSA and decreased the renal uptake by 50%. Acidification of the urine in patients may also alter the biodistribution and, in theory, may also alter the relative distribution of DMSA between asymmetrically functioning kidneys. These possibilities need to be further evaluated. Finally, since a number of variables can affect the total renal accumulation of DMSA, DMSA should not be quantitated as an absolute index of renal function unless it is done by experienced investigators under carefully controlled conditions.

Radionuclide measurement of differential glomerular filtration rate in urinary tract obstruction.

In a previous study using dogs whose renal function was rendered asymmetric by unilateral infarction, the efficacy of technetium-99m (99mTc) DTPA and DMSA in measuring differential glomerular filtration rate (GFR) was demonstrated. The present study was undertaken to determine whether the same techniques were applicable to unilateral ureteral obstruction. Five normal dogs and nine dogs with partial unilateral ureteral obstruction had determination of glomerular filtration rate by standard techniques using constant infusions of iothalamate and creatinine after ureteral catheterization. These results were compared with total GFR as measured by single injection of 99mTc DTPA and analysis of the plasma disappearance curve. Calculated differential GFR was obtained by multiplying total GFR from double exponential analysis of this curve (DTPA2) by each of three measures of differential function. These included the percent differential uptake of 99mTc DTPA and 99mTC DMSA in the posterior projection as well as the geometric mean of 99mTc DMSA uptake. There were good correlations between differential GFR determined by iothalamate clearances at ureteral catheterization and all noninvasive methods involving radionuclides and DTPA2 ( r = 0.93-0.99). Single exponential analysis of the 99mTc DTPA plasma disappearance curve was less satisfactory than double exponential analysis. These results and those reported previously support the use of radionuclides in the determination of differential GFR in a variety of clinical situations.