[Influence of the background activity region selection on the measurement of glomerular filtration rate using the Gates method].

BACKGROUND/AIM: The most frequent method for the assessment of glomerular filtration rate GFR) in clinical practice is clearance of creatinine, clearance of chromium-51 radiolabelled ethylene diamine tetraacetic acid (51Cr-EDTA) and clearance of technetium-99m radiolabelled diethylene triamine pentaacetic acid (99mTc-DTPA). The Gates method for glomerular filtration rate assessment is based on distribution of 99mTc-DTPA in the kidney 2-3 minute after its applying. Calculation of GFR is corrected for the background and depth of the kidney and finally expressed as a percentage of the net injected counts. This value of GFR highly correlates with biexponential model as the most accurate method for the assessment of GFR. The aim of this study was to determine the influence of different background sites on GFR rate assessment using the Gates method. METHODS: We analysed 50 patients who were divided into two groups: the group of healthy subjects (21 subjects, mean age 47.38 yrs) and the group of subjects with unilateral kidney damage (29 subjects, mean age 39.79 yrs). Three different background activity regions were chosen: a region drawn below the lower pole of each kidney, region drawn by the lateral side of each kidney and region drawn around the whole kidney. RESULTS: Gromerular filtration rate calculated by the use of a region under the lower pole is statistically significantly higher than GFR calculated using a region by the lateral side and around the whole kidney (p < 0.0001). Glomerular filtration rate calculated using the region by the lateral side and region around the whole kidney did not show statistically significant difference (p > 0.05). CONCLUSION: The selection of background activity region has a significant influence on GFR rate measured by the Gates method. It is recommended to use only one method for choosing the region of background activity.

Impact of micturating cystourethrography and DMSA renal scintigraphy on the investigation scheme in children with urinary tract infection.

OBJECTIVE: The relationships among urinary tract infection (UTI), vesicoureteral reflux (VUR), and permanent renal damage in children are not fully understood. The aim of this study was to evaluate the incidence of renal scarring in children with a history of UTI and to determine the change in the probability of permanent renal damage owing to the presence of VUR documented on micturating cystourethrography (MCU). METHODS: We analyzed 201 children (400 renal units, two children with solitary kidney). Seventy-four boys and 127 girls (aged 7 months to 7 years, median 2.5 years) with culture verified UTI were referred for technetium-labeled dimercaptosuccinic (DMSA) renal scintigraphy 4-6 months after acute UTI. MCU was also performed mostly 1 month prior to DMSA. Statistical analysis was performed using chi2 test or Fisher's exact test. Likelihood ratio (LR) positive and negative, diagnostic odds ratio (DOR), and post-test probability of (no) disease were calculated for VUR on MCU versus scarring on DMSA. RESULTS: Vesicoureteral reflux was found in 158 (39.5%) kidneys, and evaluated as grades I, II, III, IV, and V in 3, 70, 43, 25, and 17 refluxing renal units (RRU), respectively. Permanent renal damage according to DMSA was seen in 15.2% (61/400) kidneys. Scarring was shown in 29.7% (47/158) of kidneys with VUR and in 5.8% (14/242) kidneys without VUR (P<0.0001). LR positive was 2.353 (95% CI 1.889, 2.865), LR negative 0.341 (95% CI 0.209, 0.523), and DOR 6.895 (95% CI 3.533, 14.093). Rate of scarring significantly increased with VUR of grades III, IV, and V. There was no significant difference in the incidence of scarring in kidneys without VUR and RRU with low-grade (I and II) VUR (P=0.306). The presence of VUR on MCU increased the chance of renal damage on DMSA by about 15%, whereas negative MCU increased the chance of no-renal involvement by 9%. CONCLUSIONS: Micturating cystourethrography should not be used as a first-line test to rule out the permanent renal damage owing to UTI. The priority of imaging strategy should be focused on early identification of renal lesions to prevent further deterioration.

99mTc-MDP bone scintigraphy in the diagnosis of stress fracture of the metatarsal bones mimicking oligoarthritis.

BACKGROUND: Stress fractures are the injuries of soft tissues and bones caused by intensive and repeated stress on a bone. Repeated submaximal stress disturbs the balance between the processes of bone production and resorption that results in fracture. CASE REPORT: We presented a case of a patient with stress fracture of metatarsal bone. The patient was diagnosed and treated as having reactive oligoarthritis caused by Chlamydia trachomatis and administered antibiotics. Initial plain radiography was negative for bone fracture. Tc-99m bone scintigraphy suggested stress fracture of the second metatarsal. Plain radiography was became positive three weeks later, showing callus formation in the proximal part of the second metatarsal. CONCLUSION: Bone scintigraphy is a diagnostic test of choice in early diagnosis of stress fracture, and it is important to apply it timely in order to include the entire therapy and prevent complications, as well as to let a patient return to previous daily activities.

Technetium-99m-dimercaptosuccinic acid renal scintigraphy in children with urinary tract infections.

The aim of this study was to determine the incidence of abnormal dimercaptosuccinic acid-Tc-99m ((99m)Tc-DMSA) renal scintigraphy findings in children with culture proved urinary tract infection (UTI) with or without vesicoureteral reflux (VUR). (99m)Tc-DMSA renal scintigraphy was performed in 343 children with culture documented UTI (247 girls and 96 boys) aged from three months to 14 years (middle age of 4.82 years). The children studied were all those submitted for renal scintiscan to the Institute of Nuclear Medicine, Military Medical Academy, Belgrade during a five-year period (2000-2004). Micturating cystoureterography (MCU) performed in all patients before (99m)Tc-DMSA scan, revealed VUR in 213 children, while in 130 children VUR was not detected by MCU. In 15 of the 213 children the grade of VUR was I, in 88 was II, in 57 was III, in 33 was IV and 20 children had grade V of VUR. Findings of (99m)Tc-DMSA renal scintigraphy were classified as: normal, equivocal and abnormal. Statistical analysis was performed using c(2)test. In all patients abnormal findings were detected in 38% (131/343), normal in 51% (174/343) and equivocal findings in 11% (38/343). In children with UTI and VUR the incidence of abnormal findings was 53% (112/213), of normal 37% (80/213) and of equivocal findings 10% (21/213). In children with UTI without VUR the incidence of abnormal findings was 15% (19/130), of normal findings 72% (94/130), and of equivocal findings 13% (17/130). The incidence of abnormal findings was significantly higher in children with UTI and VUR than in those with UTI without VUR (P<0.001). In children with VUR grades I, II, III, IV and V abnormal findings were 33%, 32%, 60%, 79% and 95% respectively. The incidence of abnormal findings was higher in children with VUR grades IV and V, than in grade I and II (P<0.001). Our results suggest that (99m)Tc-DMSA renal scintigraphy in children can discriminate between grade I-II and IV-V of VUR and also that in children with UTI and VUR abnormal findings in the scintiscan were more than three times higher than in children with UTI alone.

[Renal scintigraphy in children with urinary tract infections].

BACKGROUND/AIM: To determine the incidence of abnormal Technetium Tc 99m Dimercaptosuccinic Acid (Tc99m DMSA) renal scintigraphy findings in the children with urinary tract infection (UTI), and to evaluate the difference between the children with UTI and vesico-ureteral reflux (VUR), and the children with UTI without VUR. METHODS: Tc99m DMSA renal scintigraphy was performed in 170 children with UTI, mean age 7.07 years (1 month to 14 years, 137 were girls and 33 were boys). In 88 of the children, VUR was proved by micturating cystouretherography (MCU), while in 82 VUR could not be detected by MCU. VUR was graded in accordance with MCU recommended by the intemational study of VUR. In 13 of the children the grade of VUR was grade I, in 30 was grade II, in 23 grade III, in 17 grade IV, while the grade V was in 5 of the children. Findings of Tc99m DMSA renal scintigraphy were classified as: 1--normal, 2--probably normal, 3--equivocal, 4--probably abnormal, and 5--abnormal. The degree of the significance of the difference of the findings was estimated using chi2, taking p < 0.01 as the limit of statistical significance. RESULTS: Of the total number of 170 studied children, the abnormal findings were detected in 30% (51/170), normal findings in 62% (106/170), and equivocal in 8% (13/170). In the children with UTI and VUR, the incidence of abnormal findings was 49% (43/88), of normal 43% (38/88), and of equivocal findings 8% (7/88). All the children with VUR grade V had the abnormal findings (the incidence of the abnormal findings was 100%). In the children with VUR grade IV, the abnormal findings were 71%. In the children with VUR grade I, 77% of the findings were normal, in the children with VUR grade II 53% of the findings were normal and in the children with VUR grade III, 30% otfthe findings of renal scintigraphy were normal. In the children with UTI without VUR, the incidence of abnormal findings was 10% (8/82), of normal findings 83% (68/82), and of equivocal findings 7% (6/82). The incidence of abnormal findings was significantly higher in the children with UTI and VUR than in those with UTI without VUR (p < 0.01). Also, the incidence of the abnormal findings was higher in the children with VUR grades IV and V than in the children with VUR grade I (p < 0.01). CONCLUSION: DMSA renal scintigraphy in the children with ITU revealed the abnormal findings in 30% of the cases. The incidence of the abnormallfindings was signficantly higher when VUR was present, as well as if the grade of VUR was higher. Our results confirmed that Tc99m DMSA renal scintigraphy was a very important technique in the evaluation of the children with ITU.