• The Korean Journal of Nuclear Medicine
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• v.37 no.4
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• pp.245-253
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• 2003

Puorpose: The purpose of this study was to evaluate the usefulness of $^{99m}Tc$ DMSA scintigraphy on the dignosis of a renal scar in children with urinary tract infections. Materials and Methods: Eighty three patients were included in this study, who were diagnosed as the urinary tract infection on the basis of symptom, urinalysis and urine culture. $^{99m}Tc$ DMSA scintigraphy and voiding cystoureterography were peformed within 7days before the treatment in all patients. We classified the scintigraphic findings as follow s : 1 ; a large hypoactive upper or lower pole. 2 ; a small hypoactive area. 3 ; single defect resulting in localized deformity of the outlines. 4 ; deformed outlines in a small or normal sized kidney. 5 ; multiple defects. 6 ; diffuse hypoactive kidney without regional impairment. Follow-up scintigraphy was done at least 6 months after the initial study. When the abnormality on the initial scintigraphy was not completely resolved on the follow-up scan, the lesion was defined as containing a scar. Results: One hundred and fifteen renal units of 166 units(69.3%) showed abnormal findings on the DMSA scintigraphy. 65 units(56.5%) was diagnosed as containing renal scars on follow-up scintigraphies. Incidences of renal scar among renal units showing pattern 3, 4 and 5 on the initial scan was 75%, 78% and 78%, respectively. Whereas many of renal units showing 1, 2 and 6 pattern were recovered(65%, 76%, 50%). Sensitivity, specificity and accuracy of pattern-based DMSA scintigraphic findings on the diagnosis of renal scar was 76.9%, 85.1% and 81.9%, respectively. VUR was significantly associated with the renal scar when the initial DMSA shows unrecoverable findings(pattern 3, 4, 5). Odds ratio of the renal scar in a kidney showing unrecoverable initial scintigraphic findings was 19.1. Odds ratio in a kidney with mild or moderate-to-severe VUR was 3.5 and 14.4 respectively. Conclusion: In the urinary tract infection, renal scar was significantly developed in a kidney showing unrecoverable findings on the initial DMSA scan and VUR on voiding cystoureterography.

• Investigative Magnetic Resonance Imaging
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• v.8 no.2
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• pp.100-108
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• 2004

Purpose : Early degeneration of articular cartilage is accompanied by a loss of glycosaminoglycan (GAG) and the consequent change of the integrity. The purpose of this study was to biochemically quantify the loss of GAG, and to evaluate the $Gd(DTPA)^{2-}$-enhanced, and T1, T2, rho relaxation map for detection of the early degeneration of cartilage. Materials and Methods : A cartilage-bone block in size of $8mm\;\times\;10mm$ was acquired from the patella in each of three pigs. Quantitative analysis of GAG of cartilage was performed at spectrophotometry by use of dimethylmethylene blue. Each of cartilage blocks was cultured in one of three different media: two different culture media (0.2 mg/ml trypsin solution, 1mM Gd $(DTPA)^{2-}$ mixed trypsin solution) and the control media (phosphate buffered saline (PBS)). The cartilage blocks were cultured for 5 hrs, during which MR images of the blocks were obtained at one hour interval (0 hr, 1 hr, 2 hr, 3 hr, 4 hr, 5 hr). And then, additional culture was done for 24 hrs and 48 hrs. Both T1-weighted image (TR/TE, 450/22 ms), and mixed-echo sequence (TR/TE, 760/21-168ms; 8 echoes) were obtained at all times using field of view 50 mm, slice thickness 2 mm, and matrix $256\times512$. The MRI data were analyzed with pixel-by-pixel comparisons. The cultured cartilage-bone blocks were microscopically observed using hematoxylin & eosin, toluidine blue, alcian blue, and trichrome stains. Results : At quantitation analysis, GAG concentration in the culture solutions was proportional to the culture durations. The T1-signal of the cartilage-bone block cultured in the $Gd(DTPA)^{2-}$ mixed solution was significantly higher ($42\%$ in average, p<0.05) than that of the cartilage-bone block cultured in the trypsin solution alone. The T1, T2, rho relaxation times of cultured tissue were not significantly correlated with culture duration (p>0.05). However the focal increase in T1 relaxation time at superficial and transitional layers of cartilage was seen in $Gd(DTPA)^{2-}$ mixed culture. Toluidine blue and alcian blue stains revealed multiple defects in whole thickness of the cartilage cultured in trypsin media. Conclusion : The quantitative analysis showed gradual loss of GAG proportional to the culture duration. Microimagings of cartilage with $Gd(DTPA)^{2-}$-enhancement, relaxation maps were available by pixel size of $97.9\times195\;{\mu}m$. Loss of GAG over time better demonstrated with $Gd(DTPA)^{2-}$-enhanced images than with T1, T2, rho relaxation maps. Therefore $Gd(DTPA)^{2-}$-enhanced T1-weighted image is superior for detection of early degeneration of cartilage.