Advertisement

Raw-data-based iterative reconstruction versus filtered back projection: image quality of low-dose chest computed tomography examinations in 87 patients

      Abstract

      Objective

      The objective was to compare standard-dose chest computed tomography (CT) reconstructed with filtered back projection (FBP) versus low-dose images with FBP and raw-data-based iterative reconstruction.

      Methods

      Eighty-seven consecutive patients (46 male; mean age, 54.54±16.12; mean body mass index, 24.58±4.07) referred for initial chest CT with full-dose examinations [mean dose–length product (DLP), 183.37±44.13 mGy·cm] and follow-up chest CT with half-dose examinations (mean DLP, 91.08±23.81 mGy·cm) were included. The full-dose protocol was reconstructed with FBP; the half-dose protocol was reconstructed with FBP and sinogram-affirmed iterative reconstruction (SAFIRE). Noise and signal-to-noise ratio were compared using a paired Student’s t test; subjective image quality and lesion conspicuity were compared using Wilcoxon signed ranks test.

      Results

      Actual radiation dose of follow-up CT was about 50% (49.26%±2.62%) of standard-dose protocol. Compared to full-dose images with FBP, there was no significant difference in half-dose images with SAFIRE in the objective noise (ascending aorta: P=.38, descending aorta: P=.70, trachea on mediastinal images: P=.37) and SNR (ascending aorta: P=.14, descending aorta: P=.72, trachea on mediastinal images: P=.06) on mediastinal images. Noise was significantly lower (P<.001) and SNR was significantly higher (P<.001) in half-dose images with SAFIRE on lung images. Noise was significantly higher (P<.001) and SNR was significantly lower (P<.001) in half-dose images with FBP. Subjective image quality was similar on both mediastinal images (P=.317) and lung images (P=.614) of half-dose SAFIRE images versus full-dose FBP images. Lesion conspicuity was also similar. Subjective image quality was significantly lower on both mediastinal images (P<.001) and lung images (P<.001) of half-dose FBP images versus full-dose FBP images. The conspicuity of some lesions was significantly lower (ground-glass opacity, P<.0001; ill-defined micronodule, P<.0001; lung cyst, P<.0001; emphysematous lesion, P=.003) on half-dose FBP versus full-dose FBP images.

      Conclusion

      Compared to full-dose CT images reconstructed with the conventional FBP algorithm, SAFIRE with three iterations could provide similar or better image quality at 50% less dose.

      Keywords

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to Clinical Imaging
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Kalra M.K.
        • Mather M.M.
        • Toth T.L.
        • Hamberg L.M.
        • Blake M.A.
        • Shepard J.A.
        • et al.
        Strategies for CT radiation dose optimization.
        Radiology. 2004; 230: 619-628
        • Das M.
        • Mahnken A.H.
        • Mühlenbruch G.
        • Starqardta A.
        • Weissc C.
        • Sensst D.A.
        • et al.
        Individually-adapted examination protocols for reduction of radiation exposure for 16-MDCT chest examinations.
        AJR Am J Roentgenol. 2005; 184: 1437-1443
        • Mulkens T.H.
        • Bellinck P.
        • Baeyaert M.
        • Ghysen D.
        • Van Dijck X.
        • Mussen E.
        • et al.
        Use of an automatic exposure control mechanism for dose optimization in multidetector row CT examinations: clinical evaluation.
        Radiology. 2005; 237: 213-223
        • Thibault J.B.
        • Sauer K.D.
        • Bouman C.A.
        • Hsieh J.
        A three-dimensional statistical approach to improved image quality for multislice helical CT.
        Med Phys. 2007; 34: 4526-4544
        • Brooks R.A.
        • Di Chiro G.
        Theory of image reconstruction in computed tomography.
        Radiology. 1975; 117: 561-572
        • Wang G.
        • Yu H.
        • De Man B.
        An outlook on x-ray CT research and development.
        Med Phys. 2008; 35: 1051-1064
        • Fleischmann D.
        • Boas F.E.
        Computed tomography old ideas and new technology.
        Eur Radiol. 2011; 21: 510-517
        • Leipsic J.
        • Nguyen G.
        • Brown J.
        • Sin D.
        • Mayo J.R.
        A prospective valuation of dose reduction and image quality in chest CT using adaptive statistical iterative reconstruction.
        AJR Am J Roentgenol. 2010; 195: 1095-1099
        • Leipsic J.
        • Labounty T.M.
        • Heilbron B.
        • Min J.K.
        • Mancini G.B.
        • Lin F.Y.
        • et al.
        Estimated radiation dose reduction using adaptive statistical iterative reconstruction in coronary CT angiography: the ERASIR study.
        AJR Am J Roentgenol. 2010; 195: 655-660
        • Leipsic J.
        • Labounty T.M.
        • Heilbron B.
        • Min J.K.
        • Mancini G.B.
        • Lin F.Y.
        • et al.
        Adaptive statistical iterative reconstruction: assessment of image noise and image quality in coronary CT angiography.
        AJR Am J Roentgenol. 2010; 195: 649-654
        • Moscariello A.
        • Takx R.A.
        • Schoepf U.J.
        • Renker M.
        • Zwerner P.L.
        • O'Brien T.X.
        • et al.
        Coronary CT angiography: image quality, diagnostic accuracy, and potential for radiation dose reduction using a novel iterative image reconstruction technique—comparison with traditional filtered back projection.
        Eur Radiol. 2011; 21: 2130-2138
        • Prakash P.
        • Kalra M.K.
        • Digumarthy S.R.
        • Hsieh J.
        • Pien H.
        • Singh S.
        • et al.
        Radiation dose reduction with chest computed tomography using adaptive statistical iterative reconstruction technique: initial experience.
        J Comput Assist Tomogr. 2010; 34: 40-45
        • Pontana F.
        • Pagniez J.
        • Flohr T.
        • Faivre J.B.
        • Duhamel A.
        • Remy J.
        • et al.
        Chest computed tomography using iterative reconstruction vs filtered back projection (part 1): evaluation of image noise reduction in 32 patients.
        Eur Radiol. 2011; 21: 627-635
        • Pontana F.
        • Duha.mel A.
        • Pagniez J.
        • Flohr T.
        • Faivre J.B.
        • Hachulla A.L.
        • et al.
        Chest computed tomography using iterative reconstruction vs filtered back projection (part 2): image quality of low-dose CT examinations in 80 patients.
        Eur Radiol. 2011; 21: 636-643
        • Winklehner A.
        • Karlo C.
        • Puippe G.
        • Schmidt B.
        • Flohr T.
        • Goetti R.
        • et al.
        Raw data-based iterative reconstruction in body CTA: evaluation of radiation dose saving potential.
        Eur Radiol. 2011; 21: 2521-2526
        • Bendaoud S.
        • Remy-Jardin M.
        • Wallaert B.
        • Deken V.
        • Duhamel A.
        • Faivre J.B.
        • et al.
        Sequential versus volumetric computed tomography in the follow-up of chronic bronchopulmonary diseases comparison of diagnostic information and radiation dose in 63 adults.
        J Thorac Imaging. 2011; 26: 190-195