Lung nodule detection in pediatric chest CT: Quantitative relationship between image quality and radiologist performance

Li, Xiang; Samei, Ehsan; Barnhart, Huiman X.; Gaca, A; Hollingsworth, Caroline L.; Maxfield, Charles M.; Carrico, Caroline; Colsher, James G.; Frush, Donald P.

doi:10.1118/1.3582975

Cited by 18 publications

(20 citation statements)

References 25 publications

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“…The contrast, CNR, and detectability of thin objects of different lengths are assessed with z ‐axial PVE for different imaging conditions (pitch, noise, and slice thickness). A reader study confirms that the detectability of subslice targets is CNR dependent, as expected from previous results obtained for larger objects,2, 15 and validates the relevance of the algebraic model for optimal scanning parameters choice and dose minimization.…”

Section: Introductionsupporting

confidence: 88%

Optimal slice thickness for object detection with longitudinal partial volume effects in computed tomography

Monnin¹,

Sfameni²,

Gianoli³

et al. 2016

J Applied Clin Med Phys

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Longitudinal partial volume effects (z‐axial PVE), which occur when an object partly occupies a slice, degrade image resolution and contrast in computed tomography (CT). Z‐axial PVE is unavoidable for subslice objects and reduces their contrast according to their fraction contained within the slice. This effect can be countered using a smaller slice thickness, but at the cost of an increased image noise or radiation dose. The aim of this study is to offer a tool for optimizing the reconstruction parameters (slice thickness and slice spacing) in CT protocols in the case of partial volume effects. This optimization is based on the tradeoff between axial resolution and noise. For that purpose, we developed a simplified analytical model investigating the average statistical effect of z‐axial PVE on contrast and contrast‐to‐noise ratio (CNR). A Catphan 500 phantom was scanned with various pitches and CTDI and reconstructed with different slice thicknesses to assess the visibility of subslice targets that simulate low contrast anatomical features present in CT exams. The detectability score of human observers was used to rank the perceptual image quality against the CNR. Contrast and CNR reduction due to z‐axial PVE measured on experimental data were first compared to numerical calculations and then to the analytical model. Compared to numerical calculations, the simplified algebraic model slightly overestimated the contrast but the differences remained below 5%. It could determine the optimal reconstruction parameters that maximize the objects visibility for a given dose in the case of z‐axial PVE. An optimal slice thickness equal to three‐fourth of the object width was correctly proposed by the model for nonoverlapping slices. The tradeoff between detectability and dose is maximized for a slice spacing of half the slice thickness associated with a slice width equal to the characteristic object width.

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Section: Introductionsupporting

confidence: 88%

Optimal slice thickness for object detection with longitudinal partial volume effects in computed tomography

Monnin¹,

Sfameni²,

Gianoli³

et al. 2016

J Applied Clin Med Phys

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“…Using the software, one set of patient scans can be used to generate a number of study groups, which results in no unnecessary radiation exposure for the study patients. In addition, this technology makes it possible to use archived images and to control all scan parameters other than tube current and can be used in many clinical scenarios in which CT is useful in children [16, 17]. …”

Section: Discussionmentioning

confidence: 99%

Comparison of Conventional and Simulated Reduced–Tube Current MDCT for Evaluation of Suspected Appendicitis in the Pediatric Population

Swanick

Gaca

Hollingsworth

et al. 2013

American Journal of Roentgenology

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OBJECTIVE The purpose of this study was to compare CT with conventional and simulated reduced–tube current in the evaluation for acute appendicitis in children. MATERIALS AND METHODS Validated noise-addition (tube current–reduction) software was used to create 50% and 75% tube current reductions in 60 CT examinations performed for suspected appendicitis, resulting in 180 image sets. Three blinded pediatric radiologists scored the randomized studies for the following factors: presence of the normal appendix or appendicitis (5-point scale; 1 = definitely absent and 5 = definitely present), presence of alternate diagnoses, and overall image quality (1 = nondiagnostic and 5 = excellent). Truth was defined by the interpretation of the conventional examination. RESULTS For conventional examinations, the total number of reviews (60 cases × 3 readers = 180) in which the normal appendix was identified was 120 of 180 (66.7%), compared with 108 of 180 (60%) in the 50% (p = 0.19) and 91 of 180 (50.6%) in the 75% (p = 0.002) tube current–reduction groups. Appendicitis was identified in a total of 39 of 180 (21.7%), 38 of 180 (21.1%), and 37 of 180 (20.6%) examinations, respectively (p > 0.05). This translates to sensitivities of 97% and 95% for the 50% and 75% tube current–reduction groups, respectively. Alternate diagnoses were detected in 14%, 16%, and 13% of scans, respectively. Compared with conventional–tube current examinations, reader confidence and assessment of image quality were significantly decreased for both tube current–reduction groups. CONCLUSION Simulated tube current–reduction technology provides for systematic evaluation of diagnostic thresholds. Application of this technology in the setting of suspected appendicitis shows that tube current can be reduced by at least 50% without significantly affecting diagnostic quality, despite a decrease in reader confidence and assessment of image quality.

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“…Li et al 6 have validated an earlier version of this software, and their recent work has used this tool. 7 We have also validated this version of the software, as described in a prior publication. 8 Conventionally, our spinal CTs are reconstructed with a bone kernel, a reconstruction algorithm that sharpens edges.…”

Section: Creation Of Dose-reduced Imagesmentioning

confidence: 99%

Spine Computed Tomography Radiation Dose Reduction

Swanson

Alessio

White

et al. 2015

Spine

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Spinal CT scans done for preoperative planning can be performed at 25% of current radiation doses without a loss in surgical planning measurement accuracy or precision. These 25% dose-reduced scans would have average Computed Tomography Dose Index volume dose levels of roughly 1.0 to 2.5 mGy (depending on patient size) and size-specific dose estimates of roughly 2.5 mGy representing a substantial dose savings compared to current practice for many sites. Standardization of consistent landmarks may be useful to further improve inter-rater concordance.

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Lung nodule detection in pediatric chest CT: Quantitative relationship between image quality and radiologist performance

Abstract: We quantified the relationship between image quality and the performance of radiologists in detecting lung nodules in pediatric CT. The relationship can guide CT protocol design to achieve the desired diagnostic performance at the lowest radiation dose.]

Cited by 18 publications

References 25 publications

Optimal slice thickness for object detection with longitudinal partial volume effects in computed tomography

Optimal slice thickness for object detection with longitudinal partial volume effects in computed tomography

Comparison of Conventional and Simulated Reduced–Tube Current MDCT for Evaluation of Suspected Appendicitis in the Pediatric Population

Spine Computed Tomography Radiation Dose Reduction

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