| ObjectivesTo study the twinkling artifact(TA) of ureteral stones on Doppler Sonography, and to evaluate the show rate and diagnostic value of twinkling artifact.Materials and Methods1. Patient sampleA total of 77 cases of ureteral calculi were choosed witch confirmed by spiral CT. 48 male and 29 female were included with the age from 24 to 84,49.93±11.26 in average; the height from 1.50 to 1.80m,1.66m±0.08 in average; the weight from 45kg to 100kg,73.15kg± 12.47 in average.2. Methods2.1 CT scanning:Patients were scanned by GE 64-slice Lightspeed VCT. The location and the biggest diameter after reconstructed of the stones were recorded. The stones were divided into three groups according to the position, that of proximal ureter, middle ureter and distal ureter. According to the size the stones were divided into two groups, that of<10mm and≥10mm.2.2 Ultrasound scanning:Patients were scanned on a Philips iU22 sonography system with a probe 3-5 MHz within 3 hours after the CT scanning. The doctors didn’t know the presence and location of the stone. Firstly, the B-mode examination was performed and the position and biggest diameter were recorded. Then looked for the twinkling artifact by color Doppler, and recorded its presence, width and length(TAW, TAL). A video of the twinkling artifact was saved. If the stone didn’t identified, we evaluated again all the ureter with color Doppler looking for twinkling artifact.2.3 Image processing:Photoshop CS5 and Image J were used to calculate the number of TA color pixels representing twinkling artifact intensity (TAI) and three pictures were chosed for statistical analysis.3. Statistical analysisStatistical analyses were performed using SPSS 19.0 software. All measurement data were expressed as x±s. Single factor analysis of variance (ANOVA) was performed on all data to determine if there were significant differences among four kinds of stone compositions. Students-Newman-Keuls (SNK-q) test was conducted to decide if there was significant difference between any two kinds of stone compositions.χ2 tests were used for twinkling artifact and acoustic shadowing comparisons. Pearson correlation analysis was used to analyse the relation between twinkling artifact and BMI and Skin-Stone-Distance. A P value<0.05 was considered statistically significant.Results1. The condition about the ureteral stones:77 cases were scanned by CT, including 46 cases by the left and 31 cases by the right.35 stones were located in the proximal ureter,22 stones were located in the middle ureter and 20 stones were located in the distal ureter. The stone size was 5.23-15.40mm,8.90mm±2.60 in average. There were 46 cases bigger than 10mm and 31 cases smaller than 10mm.2. The twinkling artifact and acoustic shadowing of the stones:The ultrasound diagnosed 69 stones(89.6%), with the size 5.33～15.67mm and 9.65mm±2.47 in average. The color Doppler twinkling artifact can diagnosed 65 stones(84.4%)and the B-mode can diagnosed 44 stones(57.1%).8 stones (10.4%) weren’t found by ultrasound.3. The correlation analysis of twinkling artifact with body mass index (BMI), Skin-Stone-Distance and stone size:The twinkling artifact intensity was independent of BMI and Skin-Stone-Distance(P>0.05). TAI, TAL and TAW were significantly correlated with stone diameter (r=0.614,0.240,0.509 respectively, P<0.001) for all the stones.4. Compare the measurement of CT and ultrasound:For stones<10mm and≥10mm, all ultrasound measurements greater than CT(P>0.05).ConclusionsColor Doppler twinkling artifact can obviously improve the diagnostic value of ureteral stones,especially for the atypical stones which lack of shadowing or only have dirty shadowing. The twinkling artifact is independent of BMI and Skin-Stone-Distance, which can improve the diagnostic efficiency. Twinkling artifact can display steadily, which can help ultrasonic physician to diagnose the stone quickly and it will have a wide prospect.Aims1. To quantitatively analyze the correlation between stone size and color Doppler twinkling artifact (TA) in urinary stones.2. To quantitatively analyze the relationship between chemical composition of urinary stones and acoustic shadowing.Materials and Methods1. Experimental materials:Calcium oxalate monohydrate, hydroxyapatite, cystine and uric acid were bought in Sinopharm Chemical Reagent Co.,Ltd.2. Experimental methods2.1 Preparation of artificial stones:Four kinds of powders which included calcium oxalate monohydrate, hydroxyapatite, cystine and uric acid were mixed with egg white solution under normal temperature, then put the mixture inside the oven drying for 24h, and then ground the mixture into powder. A single-punch tablet press (Shandong medical instrument factory, Zibo, China) with tablet diameters of 5.0-9.5 mm and thickness of 4.0 mm were used to create artificial stones.2.2 Phantom construction:Similar pig kidneys obtained from a local meat market. A linear slice was made through the cortex of the kidney and extended to the depth of the sinus. The artificial stone was inserted into the pig kidney within or adjacent to the sinus to simulate the in vivo situation, one at a time.2.3 Ultrasound scanning:Two hundred gram gelatin powder was mixed with 2000 mL water to form a uniform solution by a S81-2 magnetic stirrer. This matrix was poured into a rectangular plastic food container measured (24 cm×15 cm×10 cm). It was then cooled in a refrigerator until becoming firm. This echogenic gelatin matrix layer prevented strong reflection of plastic bottom that may influence the quality of sonogram. A pig kidney was placed on the surface of the bottom layer of gelatin matrix. All scans were performed on a Philips iU22 ultrasound scanner (Philips Medical Systems, Bothel, WA, USA) using an L12-5 linear array probe. The probe was mounted on a ring stand during scanning to prevent motion and to keep a fixed distance between the surface of the probe and the stones. Grey images of each stone were saved for further analysis. Machine parameters were set as the most suitable for showing of TA. Once the point of maximum twinkling was detected, a cine loop of TA was acquired and saved. The length and width of TA (TAL, TAW) were measured and recorded.2.4 CT scanning:A deep incision was made from the upper pole to the lower pole and deep to the collection system. Put the same composition phantoms into the kidney. Used the Siemens Somatom Defination CT scanner to scan the pig kidney and measured the Hounsfield unit after reconstruction.2.5 Image processing:Photoshop CS5 and Image J were used to calculate the number of TA color pixels representing twinkling artifact intensity (TAI). Image J was used to process grey pictures to get the contrast-to-noise ratio (C/N) of acoustic shadowing3. Statistical analysis:Statistical analysis was performed using SPSS 19.0 software. All measurement data were expressed as x±s. Single factor analysis of variance (ANOVA) was performed on all data to determine if there were significant differences among four kinds of stone compositions. Students-Newman-Keuls (SNK-q) test was conducted to decide if there was significant difference between any two kinds of stone compositions. A P value<0.05 was considered statistically significant.Results1. All the stone phantoms generated consistently distinguished twinkling artifact. Of all the stone phantoms, TAI was 244.00～11544.00,3279.06 in average. All the stones demonstrated as high acoustic echo with shadowing. Of all the stone phantoms, C/N ratio was 1.01～3.74,2.17 in average. Of all the stone phantoms, Hounsfield unit was 240.60～1454.00,761.34 in average.2. TAI, TAL and TAW were significantly correlated with stone diameter (r=0.374, 0.400,0.287 respectively, P<0.001) for all the stone phantoms and each compositon. 3. TAL and TAW were significantly correlated with TAI (r= 0.770、0.801 respectively, P<0.001)for all the stone phantoms each composition. TAL and TAW are good predictors of TAI.4. The hydrocyapatite stones displayed the strongest C/N ratio of acoustic shadowing and hounsfield unit, followed by calcium oxalate monohydrate, cystine and uric acid stones (all P<0.001). The C/N ratio was significantly correlated with the Hounsfield unit (r=0.942, P<0.001) for all the stone phantoms.Conclusions1. The appearance of TA is highly dependent on stone size. The intensity of TA significantly increased with increasing stone size. TAL and TAW are good predictors of TAI.2. Stones with different chemical compositions have different acoustic shadowing, but the clarity of acoustic shadowing have the same trend with the Hounsfield unit, and acoustic shadowing can be used to predict the chemical composition preliminary. |
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