Submilisievert ultralow-dose CT colonography using iterative reconstruction technique: a feasibility study

Lambert, Lukáš; Daneš, Jan; Jahoda, Jiri; Mašek, Martin; Lisý, Jiří; Ouředníček, Petr

doi:10.1177/0284185114533683

Cited by 20 publications

(19 citation statements)

References 27 publications

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“…Gryspeedt et al used a structure preserving diffusion de-noising method in 31 patients scanned with a sub-mSv technique and found this reduced noise and improved signal to noise ratios compared to sub-mSv images reconstructed without this technique [17]. Lambert et al also pushed the dose into the sub-mSv range in 16 patients using a hybrid iterative reconstruction technique and found that all segments were rated as evaluable on the low dose series reconstructed with iterative reconstruction [18]. However, no polyp assessment was performed in this study.…”

Section: Discussionmentioning

confidence: 99%

Sub-milliSievert (sub-mSv) CT colonography: a prospective comparison of image quality and polyp conspicuity at reduced-dose versus standard-dose imaging

et al. 2015

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Objective To prospectively compare reduced-dose (RD) CT colonography (CTC) with standard-dose (SD) imaging using several reconstruction algorithms. Methods Following SD supine CTC, 40 patients (mean age, 57.3 years; 17 M/23 F, mean BMI, 27.2) underwent an additional RD supine examination (targeted dose reduction, 70–90%). DLP, CTDIvol, effective dose, and SSDE were compared. Several reconstruction algorithms were applied to RD series. SD-FBP served as reference standard. Objective image noise, subjective image quality and polyp conspicuity were assessed. Results Mean CTDIvol and effective dose for RD series was 0.89 mGy (median 0.65) and 0.6 mSv (median 0.44), compared with 3.8 mGy (median 3.1) and 2.8 mSv (median 2.3) for SD series, respectively. Mean dose reduction was 78%. Mean image noise was significantly reduced on RD-PICCS (24.3±19HU) and RD-MBIR (19±18HU) compared with RD-FBP (90±33), RD-ASIR (72±27) and SD-FBP (47±14 HU). 2D image quality score was higher with RD-PICCS, RD-MBIR, and SD-FBP (2.7±0.4/2.8±0.4/2.9±0.6) compared with RD-FBP (1.5±0.4) and RD-ASIR (1.8±0.44). A similar trend was seen with 3D image quality scores. Polyp conspicuity scores were similar between SD-FBP/RD-PICCS/RD-MBIR (3.5±0.6/3.2±0.8/3.3±0.6). Conclusion Sub-milliSievert CTC performed with iterative reconstruction techniques demonstrate decreased image quality compared to SD, but improved image quality compared to RD images reconstructed with FBP.

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Section: Discussionmentioning

confidence: 99%

Sub-milliSievert (sub-mSv) CT colonography: a prospective comparison of image quality and polyp conspicuity at reduced-dose versus standard-dose imaging

et al. 2015

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“…The technical performance of an imaging test can be measured directly. Image quality at different dose levels can be compared among different CT scanners using basic phantom modules for the assessment of low-contrast and high-contrast resolution, spatial resolution or by its evaluation by independent observers (25, 26). However, to test the diagnostic performance, i.e.…”

Section: Discussionmentioning

confidence: 99%

Computed Tomography Colonography Phantom: Construction, Validation and Literature Review

et al. 2016

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BackgroundSeveral dedicated computed tomography (CT) colonography phantoms have been described previously.ObjectivesTo compare their pros and cons and describe the construction of a dedicated phantom that can be easily manufactured.Materials and MethodsWe found 15 different phantom designs by literature search and compared their advantages and disadvantages based on their description and images. We tested various materials for density and mechanical properties and constructed a phantom from polypropylene pipes (30 mm and 50 mm in diameter, 52 cm in length). Haustral folds were created by heat shaping and 39 intermediate sessile polyps with a target size of 6-10 mm and two flat lesions were created from silicone. Nine polyps were attached to a fold. The model was placed in a 30-cm barrel filled with water to simulate attenuation of human body. Attenuation of polyps was compared to intermediate polyps found in patients.ResultsNone of the earlier colonic phantoms found in the literature incorporated all the properties that would ensure both reproducibility and validity of the model (including a rigid wall, density of the wall and polyps similar to human colon, at least two levels of distension and durability). In the present phantom, the average size of sessile polyps was 8.6 ± 0.9 mm and their density was 53 ± 24 HU. We found no significant difference in polyp density between simulated polyps in the phantom and polyps in human subjects (P = 0.70). All polyps, with the exception of one flat lesion, were detected by computer aided detection.ConclusionWe constructed and validated a CT colonography phantom with correct density allowing performance of reproducible experiments.

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“…Both readers were allowed to change the densityrendering threshold (below which a voxel becomes transparent and represents intraluminal gas) to adjust the appearance of the endoluminal view. 12 Each colonic segment was evaluated in axial thin sections and 900/100-HU window setting for image quality on the same five-point Likert scale. Endoluminal density and noise expressed as standard deviation was measured in an airfilled lumen in a circular region of interest of approximately 200 mm 2 in each colonic segment.…”

Section: Methodsmentioning

confidence: 99%

“…Difficulty of constructing the fly path, which is mostly calculated automatically but has to be reworked manually in some cases, was expressed on a fivepoint scale (1, automatic; 5, impossible), and the number of computer-aided detection (CAD) strikes was recorded. 12 …”

Section: Methodsmentioning

confidence: 99%

Model-basedvshybrid iterative reconstruction technique in ultralow-dose submillisievert CT colonography

Lambert

Ouředníček²,

Jahoda³

et al. 2015

BJR

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Results: The estimated radiation dose was 0.41 6 0.05 mSv for the supine and 0.42 6 0.04 mSv for the prone acquisitions. In the endoluminal view, the image quality was rated better in HIR, whereas better scores were obtained in MBIR in the cross-sectional view, where the endoluminal noise was the lowest (p , 0.0001). Five (26%) polyps were not identified using both computeraided detection and endoluminal inspection in FBP images vs only one (5%) in MBIR and none in HIR images.Conclusion: This study showed that in submillisievert ultralow-dose CTC, the image quality for the endoluminal view is better when HIR is used, whereas MBIR yields superior images for the cross-sectional view. The inferior quality of images reconstructed with FBP may result in decreased detection of colonic lesions. Advances in knowledge: Radiation dose from CTC can be safely reduced ,1 mSv for both positions when iterative reconstruction is used. MBIR provides better image quality in the cross-sectional view and HIR in the endoluminal view.

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Submilisievert ultralow-dose CT colonography using iterative reconstruction technique: a feasibility study

Cited by 20 publications

References 27 publications

Sub-milliSievert (sub-mSv) CT colonography: a prospective comparison of image quality and polyp conspicuity at reduced-dose versus standard-dose imaging

Sub-milliSievert (sub-mSv) CT colonography: a prospective comparison of image quality and polyp conspicuity at reduced-dose versus standard-dose imaging

Computed Tomography Colonography Phantom: Construction, Validation and Literature Review

Model-basedvshybrid iterative reconstruction technique in ultralow-dose submillisievert CT colonography

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