Image quality improvement using an image-based noise reduction algorithm: Initial experience in a phantom model for urinary stones

Shadpour Demehri, Pascal Salazar, Michael L. Steigner, Stefan Atev, Osama Masoud, Philippe Raffy, Scott A. Jacobs, Frank J. Rybicki

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


OBJECTIVE: To determine signal-to-noise (SNR), contrast-to-noise ratio, and segmentation error measurements in various low-dose computed tomographic (CT) acquisitions of an anthropomorphic phantom containing urinary stones before and after implementation of a structure-preserving diffusion (SPD) denoising algorithm, and to compare the measurements with those of standard-dose CT acquisitions. METHODS: After institutional review board approval, written informed consent was waived and 36 calcium oxalate stones were evaluated after CT acquisitions in an anthropomorphic phantom at variable tube currents (33-137 mA s). The SPD denoising algorithm was applied to all images. Signal-to-noise ratio, contrast-to-noise ratio, and expected segmentation error were determined using manually drawn regions of interest to quantify the effect of the noise reduction on the image quality. RESULTS: The value of segmentation error measurements using the SPD denoising algorithm obtained at tube currents as low as 33 mA s (up to 75% dose reduction level) were similar to standard imaging at 137 mA s. The denoised images at reduced doses up to 75% dose reduction have higher SNR than the standard-dose images without denoising (P < 0.005). Stepwise regression showed significant (P < 0.001) effect of dose length product on SNR, and segmentation error measurements. CONCLUSIONS: Based on objective noise-related image quality metrics, the SPD denoising algorithm may be useful as a robust and fast tool, and it has the potential to improve image quality in low-dose CT ureter protocols.

Original languageEnglish (US)
Pages (from-to)610-615
Number of pages6
JournalJournal of computer assisted tomography
Issue number5
StatePublished - 2012
Externally publishedYes


  • CT
  • CT noise
  • image quality
  • structure-preserving diffusion algorithm
  • urinary stone

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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