J Korean Soc Med Ultrasound.  2002 Sep;21(3):213-218.

Twinkling Artifact on Color Doppler Ultrasound: Comparison among Various Composition of Stones and Various Central Frequencies of Transducers

Affiliations
  • 1Department of Radiology, Keimyung University School of Medicine, Korea.
  • 2Department of Radiology, University of Ulsan College of Medicine Asan Medical Center, Korea.

Abstract

PURPOSE: To evaluate the relationship between the degree of twinkling artifact generated on color Doppler sonography and the biochemical composition of renal stones and different central frequencies of transducers.
MATERIALS AND METHODS
Three types of renal stones (A = 90% calcium oxalate + 10% calcium hydrogen phosphate, B = 50% calcium oxalate + 5% calcium hydrogen phosphate + 45% ammonium urate, and C = 55% urate + 35% calcium oxalate + 5% ammonium urater + 5% calcium hydrogen phosphate) removed from the subjects and one artificially made plastic-ball (D) were examined in vitro with color Doppler ultrasonography. Four transducers (C4-5, C7-4, L7-4, L10-5MHz) were used. All stones were placed in a depth of between 3 and 4 cm in an agar plate. Grading of twinkling artifact was done: 0 = absent, 1 = present but occupying less than half of a stone, 3 = occupying the entire stone and 2 = between 1 and 3. Color Doppler gain was set to the point just below the threshold for color noise. Each artifact was graded by two independent observers, and if there was interobserver difference, the consensus was reached.
RESULTS
The size of stones ranged from 6 to 10mm (mean = 8mm). Type A stone produced grade 1 artifact on C4-2, grade 2 on C7-4 and grade 3 on L7-4 and L10-5. Type B stone produced grade 1 artifact on all transducers; type C stone produced grade 0 artifact on C4-2, grade 2 on C7-4, and grade 1 on L7-4, and L10-5. The plastic ball produced grade 1 artifact on L10-5, and grade 0 on other transducers.
CONCLUSION
Different grades of twinkling artifact on color Doppler ultrasonography were evoked depending on the biochemical composition of renal stones and different central frequencies of transducers. The major limitation of our study was that the number of the subjects were small.


MeSH Terms

Agar
Ammonium Compounds
Artifacts*
Calcium
Calcium Oxalate
Consensus
Hydrogen
Noise
Plastics
Transducers*
Ultrasonography*
Ultrasonography, Doppler, Color
Uric Acid
Agar
Calcium
Calcium Oxalate
Hydrogen
Plastics
Uric Acid
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