Inter- and intraobserver variability of (99m)Tc-DMSA renal scintigraphy: impact of oblique views

(99m)Tc-Dimercaptosuccinic acid (DMSA) scintigraphy is a frequently used diagnostic test to assess the presence and severity of cortical damage. The aim of this study is to investigate the variability in the interpretation of (99m)Tc-DMSA scans, evaluate the usefulness of oblique images, and assess their impact on scan interpretation. METHODS: Two experienced nuclear medicine physicians independently interpreted 100 (99m)Tc-DMSA scans (197 kidneys) 4 times. Interpretation was twice based on posterior projection images and twice based on posterior and posterior oblique projection images. For each kidney, the observers had to choose between the following results: normal, abnormal, and indeterminate. The indices of variability used were the percentage of agreement, kappa-statistic, and marginal homogeneity. RESULTS: Intraobserver and interobserver reproducibility (kappa-values) varied between 0.683 and 0.708 and between 0.609 and 0.671, respectively, for posterior images. Disagreement in (99m)Tc-DMSA scan interpretation occurred in 18% of kidneys within observers and in 21% of kidneys between observers when only posterior images were used. Oblique views changed the interpretation in 14% and 11.5% of kidneys for the first and second observers, respectively. The use of oblique views increased the agreement rate within and between observers (kappa-values, 0.725-0.812 and 0.768-0.732, respectively; mean agreement, 86.5 and 87.25, respectively). CONCLUSION: Oblique views were found useful in approximately 13% of kidneys and affected inter- and intraobserver variability. Our results suggest that oblique views should be used routinely in children with clinically suspected urinary tract infection to reliably interpret images.     

(99m)Tc-DMSA scintigraphy diagnosing crossed renal ectopia with fusion in a three years old boy

A 3 years old boy with a history of surgery for orchidopexy was admitted to our hospital with fever and abdominal pain. Clinical examination and laboratory investigations revealed urinary tract infection with renal involvement. Ultrasonography demonstrated a solitary left kidney and raised the suspicion of a fusion anomaly. Voiding cystography disclosed grade III vesicoureteral reflux and technetium-99m dimercaptosuccinic acid scintigraphy revealed right to left crossed renal ectopia with fusion (L-shaped kidney). The patient is undergoing standard follow-up for the early detection of possible renal complications. In conclusion, L-shaped kidney is a rare entity and the (99m)Tc-DMSA scintigraphy played an important role on timely diagnosis.     

The utility of (99m)Tc-DMSA and Tc(99m)-EC scintigraphy for early diagnosis of ifosfamide induced nephrotoxicity.

A serious undesired effect of certain cytostatics is their nephrotoxicity. In this study, we investigated the toxic effects of ifosfamide and cisplatin by clinical and biochemical parameters in relation to (99m)Tc-dimercaptosuccinic acid ((99m)Tc-DMSA) and Tc(99m)N, N-ethylenedicysteine (EC) renal scintigraphy. The indicators were urinary beta2-microglobulin levels, tubular resorption of phosphate, urinary protein and glucose excretion, glomerular filtration rate, urinary pH and osmolarity. Thirteen paediatric patients (seven boys and six girls), aged 2-16 years, were investigated. Five patients received only cisplatin, six patients were treated with ifosfamide and cisplatin and two with ifosfamide and carboplatin for various malignancies. All except three patients had normal DMSA uptake (median, 19; range, 16-29%) prior to chemotherapy. The reduction in DMSA uptake was unilateral due to tumour invasion in those three patients. Following chemotherapy, DMSA uptake showed reduction in five patients with or without clinical nephrotoxicity. The observed pattern was decreased renal uptake and elevated bladder activity. Three patients with decreased DMSA uptake had normal tubular maximum phosphate reabsorption, which suggested subclinical injury. Decrease in DMSA uptake and tubular phosphate reabsorption (TPR) was detected simultaneously in two patients. No abnormalities were seen on Tc(99m)-EC scintigraphy to suggest nephrotoxicity in our investigation. However, Tc(99m)-EC clearly demonstrated a reduction in split renal function in children with tumour invasion. In summary, we found that ifosfamide induced tubular injury can be detected with (99m)Tc-DMSA scintigraphy before chemotherapy associated nephrotoxicity is observed by laboratory measurements. Our results also imply that, although a tubular agent, renal scintigraphy performed with Tc(99m)-EC is not able to detect subclinical injury or predict the outcome during treatment.     

123I-hippuran renal scintigraphy with evaluation of single-kidney clearance for predicting renal scarring after acute urinary tract infection: comparison with (99m)Tc-DMSA scanning.

The value of (123)I-hippuran (OIH) renal sequential scintigraphy (RSS) in predicting the evolution of defects detected by (99m)Tc-dimercaptosuccinic acid (DMSA) scanning during a first episode of acute pyelonephritis (APN) was assessed. METHODS: Fifty-eight children with APN underwent (99m)Tc-DMSA planar scanning and (123)I-OIH RSS during acute infection and at least 5 mo later. Renal lesions found by (99m)Tc-DMSA scanning were classified according to the following (99m)Tc-DMSA grading system: 0 = normal, 1 = 1 lesion, 2 = 2 lesions, and 3 = diffuse damage with renal parenchymal subversion. Renal scarring was diagnosed whenever a renal cortical defect detected at the first (99m)Tc-DMSA examination persisted on the follow-up (99m)Tc-DMSA examination. Single-kidney clearance rate (Cl) was evaluated by a method that was previously validated at our institution and is based on time-activity curves measured on the heart and kidney areas by the region-of-interest technique. RESULTS: (99m)Tc-DMSA scanning showed renal damage in 76 kidneys and had negative findings for the remaining 40 kidneys (2 patients had bilaterally negative findings). (99m)Tc-DMSA scanning determined 40 kidneys to be grade 0, 49 to be grade 1, 21 to be grade 2, and 6 to be grade 3. For (99m)Tc-DMSA grades of 0-3, the corresponding Cl mean values (in mL/min/1.73 m(2) of body surface area [BSA]) were 292 +/- 33, 237 +/- 39, 210 +/- 54, and 140 +/- 53, respectively. The Spearman regression coefficient (R) demonstrated a significant correlation between (99m)Tc-DMSA grade and Cl (R = 0.69, P < 0.0001). Thirty-six of the lesions detected by staging (99m)Tc-DMSA were shown to have recovered on follow-up renal scans, whereas 40 developed scars. A significant difference in Cl was found between the 2 groups (P < 0.0002). The Cl cutoff value was determined by univariate discriminant analysis; a Cl value of 232 mL/min/1.73 m(2) of BSA discriminated best between scarred and nonscarred kidneys, with a specificity, sensitivity, positive predictive value, negative predictive value, and overall accuracy of 95%, 95%, 90%, 97%, and 95%, respectively. CONCLUSION: Cl evaluation, in the course of acute urinary tract infection, is highly valuable in predicting the fibrotic evolution of renal damage detected on acute (99m)Tc-DMSA scanning. Also, our data show close agreement between Cl and the grade determined by staging (99m)Tc-DMSA.     

Alteration of the organ uptake of the (99m)Tc-radiopharmaceuticals, (99m)Tc-DPD, (99m)Tc-DMSA, (99m)Tc-tin colloid and (99m)Tc-MAA, induced by the applied cytotoxic drugs methotrexate sodium and cyclophosphamide

AIM: To investigate the influence of certain cytotoxic drugs on the organ uptake of the following (99m)Tc-radiopharmaceuticals: (99m)Tc-2,3-dicarboxypropane-1,1-diphosphonic acid ((99m)Tc-DPD), (99m)Tc-meso-2,3-dimercaptosuccinic acid ((99m)Tc-DMSA), (99m)Tc-tin colloid and (99m)Tc-macroaggregated albumin ((99m)Tc-MAA). Methotrexate sodium and cyclophosphamide were used as models to evaluate these effects. METHODS: Two groups of healthy male Wistar rats were treated separately by oral application of the drugs for 7 days. On the eighth day, each of the (99m)Tc-radiopharmaceuticals was applied in a separate group of treated animals. They were sacrificed at different time intervals and the radioactivity in the organs of interest was measured. The organ uptake of the (99m)Tc-radiopharmaceuticals in an additional control group of animals was also studied. RESULTS: The results obtained showed an alteration in the organ uptake of (99m)Tc-radiopharmaceuticals in animals treated with cytotoxic drugs. In rats treated with methotrexate sodium, there was a higher uptake of (99m)Tc-DMSA in the bones, stomach and intestine, a higher uptake of (99m)Tc-DPD in the bones, intestine, blood and muscle, a lower uptake of (99m)Tc-tin colloid in the liver and a lower accumulation of (99m)Tc-MAA in the lungs. Cyclophosphamide-treated animals showed enhanced uptake of (99m)Tc-DMSA in the kidneys, a twofold enhanced uptake of (99m)Tc-DPD in all organs except the stomach, a decreased uptake of (99m)Tc-tin colloid in the lungs, spleen and kidneys and a significantly decreased uptake of (99m)Tc-MAA in the lungs. CONCLUSION: These results confirm that both methotrexate sodium and cyclophosphamide may alter the organ uptake of (99m)Tc-radiopharmaceuticals in experimental animals.     

Visualization of bladder diverticulum during Tc-99m DTPA renal scintigraphy

An eight-year-old boy with recurrent urinary infection underwent Tc-99m DTPA renal scintigraphy for the evaluation of renal function. Stasis of the tracer was observed in the pelvocalyceal systems of both kidneys. Intravenous diuretic was administered to evaluate a possible mechanical obstruction. During the course of the study, a well-defined, round area of activity extended from the bladder which was subsequently confirmed to be a diverticulum on voiding cystourethrogram and at surgery.     

Utility of Tc-99m GSA whole-body scintigraphy in detecting bone metastases from hepatocellular carcinoma

Recent advances in the treatment of hepatocellular carcinoma (HCC) have prolonged patient survival. However, the number of patients with bone metastases identified during follow-up examinations has increased. Tc-99m Sn-N-pyridoxy-5-methyltryptophan (Tc-99m PMT) has been reported to accumulate at a high rate in HCC lesions and bone metastases. In the patient described here, whole-body scintigraphy showed accumulation of DTPA galactosyl human serum albumin (Tc-99m GSA) and Tc-99m PMT in bone metastases from HCC. The authors suggest that asialoglycoprotein receptors may be present in bone metastases from well-differentiated HCC. Tc-99m GSA whole-body imaging can be used to detect bone metastases from HCC and to evaluate hepatic reserve.     

Evaluation of hepatic function with (99m)Tc-galactosylated serum albumin scintigraphy in patients with malaria: comparison with (99m)Tc-colloid scintigraphy and liver ultrasonography

OBJECTIVE: Malarial parasites injected by the mosquito rapidly target hepatocytes, and hepatomegaly is commonly observed during the progress of the disease in malaria patients. To evaluate the degree of hepatic damage and functional status of hepatocytes in malaria patients, we performed liver scintigraphy using (99m)Tc-galactosylated serum albumin (GSA) prospectively and the findings were compared with those of (99m)Tc-colloid scintigraphy, ultrasonography and clinical results in the same subject. METHODS: Eight malaria patients (all male, mean age 22 years) confirmed to be infected with Plasmodium vivax underwent (99m)Tc-GSA liver scintigraphy, followed by liver ultrasonography and (99m)Tc-colloid scintigraphy using phytate within 3 days. For hepatocyte scintigraphy, anterior images of cardiac blood-pool and liver were continuously acquired for 30 min after injection of 185 MBq (99m)Tc-GSA (3 mg). In addition to visual interpretation of the images, quantitative measurement of hepatic function was performed with several functional parameters, such as hepatic uptake index (LHL15), blood clearance index (HH15) and modified receptor index (LHL/HH) calculated from the radioactivity of the liver and heart. (99m)Tc-colloid images were assessed and graded visually. Severity of hepatic dysfunction or reticuloendothelial system activation was classified as normal, mild, moderate and severe on GSA or colloid images. RESULTS: Hepatomegaly was observed in five and splenomegaly in seven of the eight patients. Serum levels of transaminase and alkaline phosphatase were mildly elevated in two. Visual assessment of GSA scintigraphy revealed normal findings in all subjects, except for mild increases in size. The mean values of LHL15, HH15 and LHL/HH were 0.928+/-0.014, 0.537+/-0.031 and 1.732+/-0.106, respectively. They were graded as normal in five, and near-normal to mild dysfunction in three subjects. In contrast, (99m)Tc-colloid scintigraphy revealed abnormal findings in all of the subjects, and graded as moderate in three or severe reticuloendothelial system activation in five subjects. Liver ultrasonographic findings were normal for all subjects except mild hepatomegaly. CONCLUSIONS: Malaria-induced injury of the hepatocyte is likely to be minimal whereas hepatomegaly is commonly seen during disease process. This suggests that hepatic damage in malarial infection is mainly due to involvement of the reticuloendothelial system. (99m)Tc-GSA scintigraphy can be used in differentiating hepatocellular damage from reticuloendothelial system involvement in patients with infectious disease showing hepatomegaly.     

Technetium-99m MAG3 renal scintigraphy with demonstration of aortic dissection

Demonstration of type B aortic dissection is rare during renal scintigraphy. The discordant radionuclide pattern of asymmetric renal flow with equivalent renal function and excretion has been previously reported in aortic dissection. However, delayed scintigraphic features of the false lumen have not been described. The author presents such a case with persistent technetium-99m MAG3 accumulation in the posterior mediastinum on postvoid planar imaging.     

Comparison of Tc-99m EC and Tc-99m DTPA captopril scintigraphy to diagnose renal artery stenosis.

PURPOSE: Although, captopril scintigraphy is a well established method to detect renovascular hypertension, the optimal radiopharmaceutical for this test remains to be determined. Recently, Tc-99m ethylenedicysteine (Tc-99m EC) appeared as an alternative agent for captopril scintigraphy. The aim of this study was to compare the diagnostic accuracy of Tc-99m EC with Tc-99m DTPA, which is a well-established renal radiopharmaceutical for the captopril test. METHODS: Nineteen hypertensive patients who had various degrees of renal artery stenosis on angiography were included in the study. All patients had baseline and captopril Tc-99m EC and Tc-99m DTPA scintigraphy within a 1-week period. The results were compared with angiography and in eight patients with changes in blood pressure after revascularization. The images were interpreted without knowledge of the angiography and revascularization data as low, intermediate, or high probability for hemodynamically significant renal artery stenosis, which was defined as an area of stenosis exceeding 50%. RESULTS: Tc-99m EC and Tc-99m DTPA study results were in agreement in 16 of the 19 patients. In two patients with branch artery stenosis, Tc-99m EC was definitely superior to Tc-99m DTPA and correctly identified the probability of stenosis on scintigraphy. On kidney analysis, Tc-99m EC had a slightly greater diagnostic sensitivity compared with Tc-99m DTPA (79% vs. 68%; P > 0.05 by the chi-squared test) but equal specificity (93% for both agents). Both Tc-99m EC and Tc-99m DTPA showed the same accuracy in predicting the outcome after revascularization in all but one patient with branch artery stenosis, in whom Tc-99m EC accurately predicted a successful outcome of the intervention but Tc-99m DTPA did not. Tc-99m EC had better renal uptake in patients with decreased renal function and provided more dramatic evidence of renogram changes after captopril intervention, which resulted in more confident interpretation. CONCLUSIONS: There is no significant difference between Tc-99m EC and Tc-99m DTPA captopril scintigraphy for detecting renal artery stenosis. However, because of the better imaging characteristics and more confident interpretation provided by the dramatic changes in the degree of renogram abnormality after captopril intervention, Tc-99m EC captopril scintigraphy should be used, particularly in patients with decreased renal function or branch artery stenosis.     

99Tcm-DMSA肾皮质显像诊断小儿肾发育不良

目的 探讨^99Tc^m—二巯基丁二酸(DMSA)肾皮质显像诊断小儿肾发育不良的价值。方法 疑为肾发育不良患儿29例，行常规^99Tc^m—DMSA肾皮质显像和腹部B超检查。图像分析：将发育不良肾分为0～4级。结果 ^99Tc^m—DMSA肾皮质显像示29例患儿中24例为单侧肾发育不良，其中11例1级，7例2级，6例3级，余5例患肾未显影为0级，结合其他：检查诊断为肾发育不良。患肾分肾功能为0～24．9％(平均6．3％)。29例患儿中24例患肾肾皮质显像诊断为肾发育不良，5例患肾未显影，由其他影像学方法确诊，诊断灵敏度为82．76％。29例中19例经手术治疗，病理检查证实为肾发育不良。结论 ^99Tc^m—DMSA肾皮质显像诊断肾发育不良灵敏度高、可靠，可确定发育不良肾部位和判断肾功能。     

99mTc-MAEC complexes: new renal radiopharmaceuticals combining characteristics of (99m)Tc-MAG3 and (99m)Tc-EC.

99mTc-Mercaptoacetyltriglycine ((99m)Tc-MAG3) and (99m)Tc-L,L-ethylenedicysteine ((99m)Tc-LL-EC) are useful renal radiopharmaceuticals; however, both agents have renal clearances less than that of (131)I-orthoiodohippurate ((131)I-OIH), and (99m)Tc-LL-EC exists in dianionic and monoanionic forms at physiologic pH. In an effort to develop a superior (99m)Tc agent with a rapid clearance comparable with that of (131)I-OIH, we have designed a new ligand system, mercaptoacetamide-ethylene-cysteine (MAEC), which combines important structural features of both MAG3 and EC. METHODS: Biodistribution and clearance studies were performed on Sprague-Dawley rats using syn- and anti-(99m)Tc-L- and -D-MAEC coinjected with (131)I-OIH. Studies were also performed by coinjecting each isomer ( approximately 74 MBq [ approximately 2 mCi]) and 7.4-11.1 MBq (200-300 micro Ci) of (131)I-OIH in 3 volunteers with dual-isotope imaging performed using a camera system fitted with a high-energy collimator. Blood samples were obtained from 3 to 90 min after injection and urine samples were obtained at 30, 90, and 180 min. RESULTS: In the rats, <10% of the injected dose remained in the blood at 10 min after injection for all isomers, and the urine dose at 60 min ranged from 84% to 99% that of (131)I-OIH. The clearances of syn- and anti-(99m)Tc-L-MAEC in the rats were higher than the clearances for the D-isomers (P 相似文献