Improvement of Low-Contrast Detectability in Low-Dose Hepatic Multidetector Computed Tomography Using a Novel Adaptive Filter

Funama, Yoshinori; Awai, Kazuo; Miyazaki, Osamu; Nakayama, Yoshiharu; Goto, T.; Omi, Yasuo; Shimonobo, Toshiaki; Liu, Duo; Yamashita, Yasuyuki; Hori, Shingo

doi:10.1097/01.rli.0000188026.20172.5d

Cited by 53 publications

(30 citation statements)

References 26 publications

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“…Low-pass (smoothing) algorithms reduce noise by filtering out higher frequencies; however, the filtering is indiscriminate and important object boundaries can be smoothed concomitantly [21]. Data presented here for the smoothing algorithm further support this low-pass limitation and emphasise that preservation of interfaces is required for the detection of low-contrast objects.…”

Section: Discussionmentioning

confidence: 71%

Noise-reducing algorithms do not necessarily provide superior dose optimisation for hepatic lesion detection with multidetector CT

Dobeli¹,

Lewis²,

Meikle³

et al. 2013

The British Journal of Radiology

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Cite this article as: Dobeli KL, Lewis SJ, Meikle SR, Thiele DL, Brennan PC. Noise-reducing algorithms do not necessarily provide superior dose optimisation for hepatic lesion detection with multidetector CT. Br J Radiol 2013;86:20120500. Noise-reducing algorithms do not necessarily provide superior dose optimisation for hepatic lesion detection with multidetector CT Objective:To compare the doseoptimisation potential of a smoothing filtered backprojection (FBP) and a hybrid FBP/iterative algorithm to that of a standard FBP algorithm at three slice thicknesses for hepatic lesion detection with multidetector CT.Methods: A liver phantom containing a 9.5-mm opacity with a density of 10 HU below background was scanned at 125, 100, 75, 50 and 25 mAs. Data were reconstructed with standard FBP (B), smoothing FBP (A) and hybrid FBP/iterative (iDose 4 ) algorithms at 5-, 3-and 1-mm collimation. 10 observers marked opacities using a four-point confidence scale. Jackknife alternative freeresponse receiver operating characteristic figure of merit (FOM), sensitivity and noise were calculated.Results: Compared with the 125-mAs/5-mm setting for each algorithm, significant reductions in FOM (p,0.05) and sensitivity (p,0.05) were found for all three algorithms for all exposures at 1-mm thickness and for all slice thicknesses at 25 mAs, with the exception of the 25-mAs/5-mm setting for the B algorithm. Sensitivity was also significantly reduced for all exposures at 3-mm thickness for the A algorithm (p,0.05). Noise for the A and iDose 4 algorithms was approximately 13% and 21% lower, respectively, than for the B algorithm.Conclusion: Superior performance for hepatic lesion detection was not shown with either a smoothing FBP algorithm or a hybrid FBP/iterative algorithm compared with a standard FBP technique, even though noise reduction with thinner slices was demonstrated with the alternative approaches.

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Section: Discussionmentioning

confidence: 71%

Noise-reducing algorithms do not necessarily provide superior dose optimisation for hepatic lesion detection with multidetector CT

Dobeli¹,

Lewis²,

Meikle³

et al. 2013

The British Journal of Radiology

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“…The largest dose decrease for the thoracic imaging was achieved for the CT of the pulmonary arteries (up to 42%). However, no reduction of the radiation dose was achieved after the education and training programme for abdominal CT. A possible explanation for this finding might be the radiologists' concerns about suboptimal image quality resulting from lower dose CT protocols, possibly leading to a greater risk of overlooking low contrast lesions [21][22][23][24]. Conversely, a marked reduction in the radiation dose is feasible in thoracic CT imaging because the increase in image noise is compensated for by the inherent contrast between air (lower attenuation) and the pulmonary vessels and interstitial structures (higher attenuation).…”

Section: Discussionmentioning

confidence: 99%

An education and training programme for radiological institutes: impact on the reduction of the CT radiation dose

et al. 2011

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Objectives To establish an education and training programme for the reduction of CT radiation doses and to assess this programme's efficacy. Methods Ten radiological institutes were counselled. The optimisation programme included a small group workshop and a lecture on radiation dose reduction strategies. The radiation dose used for five CT protocols (paranasal sinuses, brain, chest, pulmonary angiography and abdomen) was assessed using the dose-length product (DLP) before and after the optimisation programme. The mean DLP values were compared with national diagnostic reference levels (DRLs). Results The average reduction of the DLP after optimisation was 37% for the sinuses (180 vs. 113 mGycm, P< 0.001), 9% for the brain (982 vs. 896 mGycm, P<0.05), 24% for the chest (425 vs. 322 mGycm, P<0.05) and 42% for the pulmonary arteries (352 vs. 203 mGycm, P<0.001). No significant change in DLP was found for abdominal CT. The post-optimisation DLP values of the sinuses, brain, chest, pulmonary arteries and abdomen were 68%, 10%, 20%, 55% and 15% below the DRL, respectively. Conclusions The education and training programme for radiological institutes is effective in achieving a substantial reduction in CT radiation dose.

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“…4 A technique using a noise reduction fi lter is useful for reducing the radiation dose at CT examination. [5][6][7][8] We previously reported the usefulness of our novel adaptive noise reduction fi lter during hepatic CT. 9,10 In that study, we used a computer-simulated liver phantom and a fi xed fi lter magnitude to achieve smoothness and sharpness because the size of the phantom was constant. We found that the radiation dose could be reduced by 50% without losing low-contrast detectability.…”

Section: Introductionmentioning

confidence: 99%

“…We also conducted a clinical study involving 15 patients to examine the characteristics of the constant fi lter. 10 For routine clinical practice, the effect of the fi lter may vary according to patient conditions such as body weight. Therefore, optimizing the adaptive noise-reduction fi lter according to the patient constitution (body weight) may be required.…”

Section: Introductionmentioning

confidence: 99%

Radiation dose reduction in hepatic multidetector computed tomography with a novel adaptive noise reduction filter

Funama¹,

Awai²,

Miyazaki³

et al. 2008

Radiat Med

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Improvement of Low-Contrast Detectability in Low-Dose Hepatic Multidetector Computed Tomography Using a Novel Adaptive Filter

Abstract: The radiation dose can be reduced by 50% without loss of nodule detectability by applying the adaptive noise reduction filter to simulated and patient liver images obtained at MDCT.

Cited by 53 publications

References 26 publications

Noise-reducing algorithms do not necessarily provide superior dose optimisation for hepatic lesion detection with multidetector CT

Noise-reducing algorithms do not necessarily provide superior dose optimisation for hepatic lesion detection with multidetector CT

An education and training programme for radiological institutes: impact on the reduction of the CT radiation dose

Radiation dose reduction in hepatic multidetector computed tomography with a novel adaptive noise reduction filter

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