title: Computer-aided detection of renal calculi from noncontrast CT images using TV-flow and MSER features.
abstract: OBJECTIVE
  Renal calculi are common extracolonic incidental findings on computed tomographic colonography (CTC). This work aims to develop a fully automated computer-aided diagnosis system to accurately detect renal calculi on CTC images.
  
  
  METHODS
  The authors developed a total variation (TV) flow method to reduce image noise within the kidneys while maintaining the characteristic appearance of renal calculi. Maximally stable extremal region (MSER) features were then calculated to robustly identify calculi candidates. Finally, the authors computed texture and shape features that were imported to support vector machines for calculus classification. The method was validated on a dataset of 192 patients and compared to a baseline approach that detects calculi by thresholding. The authors also compared their method with the detection approaches using anisotropic diffusion and nonsmoothing.
  
  
  RESULTS
  At a false positive rate of 8 per patient, the sensitivities of the new method and the baseline thresholding approach were 69% and 35% (p < 1e - 3) on all calculi from 1 to 433 mm(3) in the testing dataset. The sensitivities of the detection methods using anisotropic diffusion and nonsmoothing were 36% and 0%, respectively. The sensitivity of the new method increased to 90% if only larger and more clinically relevant calculi were considered.
  
  
  CONCLUSIONS
  Experimental results demonstrated that TV-flow and MSER features are efficient means to robustly and accurately detect renal calculi on low-dose, high noise CTC images. Thus, the proposed method can potentially improve diagnosis.
authors.affiliation: Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, Maryland 20892-1182.
authors.forename: Jianfei
authors.initials: J
authors.lastname: Liu
authors.affiliation: Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, Maryland 20892-1182.
authors.forename: Shijun
authors.initials: S
authors.lastname: Wang
authors.affiliation: Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, Maryland 20892-1182.
authors.forename: Evrim B
authors.initials: EB
authors.lastname: Turkbey
authors.affiliation: Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Health System Center, Washington, DC 20010 and School of Medicine and Health Sciences, George Washington University, Washington, DC 20010.
authors.forename: Marius George
authors.initials: MG
authors.lastname: Linguraru
authors.affiliation: Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, Maryland 20892-1182.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Yao
authors.affiliation: Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, Maryland 20892-1182.
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Summers
mesh_terms: D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D006801:Humans; D007669:Kidney Calculi / Q000000981:diagnostic imaging*; D011829:Radiation Dosage; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000379:methods*