Detection of liver metastases under 2 cm: comparison of different acquisition protocols in four row multidetector-CT (MDCT)

Abdelmoumene, A.; Chevallier, P.; Chalaron, Marc; Schneider, Frédéric; Verdun, Francis R.; Frascarolo, Philippe; Meuli, Reto; Schnyder, P.; Denys, Alban

doi:10.1007/s00330-005-2741-x

Cited by 47 publications

(23 citation statements)

References 28 publications

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“…For the MDCT imaging, three-phasic dynamic images, including arterial, portal venous, and equilibrium phases, were acquired at 3 mm reconstruction thickness, using a detector collimation of 1.5 mm. Recent study about determining the optimal CT protocol for detection of hepatic metastases using four-slice MDCT [30] has shown that a thin section of 2.5 mm or an increased table speed are less efficient in detecting small metastases, even though MDCT with a different detector configuration from ours was used in that study. Moreover, we utilized a highly concentrated iodine contrast agent [31,32] to maximize the lesion-to-liver contrast.…”

Section: Discussionmentioning

confidence: 84%

Detection and characterization of liver metastases: 16--slice multidetector computed tomography versus superparamagnetic iron oxide-enhanced magnetic resonance imaging

Kim

Hwang

et al. 2006

Eur Radiol

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The aim of our study was to compare the diagnostic performance of 16--slice multidetector computed tomography with that of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging in the detection of small hepatic metastases and in the differentiation of hepatic metastases from cysts. Twenty-three patients with 55 liver metastases and 14 liver cysts underwent SPIO-enhanced MR imaging and multiphasic CT using 16-MDCT. Two observers independently analyzed each image, in random order. Sensitivity and diagnostic accuracy for lesion detection and differentiation as metastases or cysts for MDCT and SPIO-enhanced MR imaging were calculated using receiver operating characteristic analysis. For all observers, the Az values of SPIO-enhanced MR imaging for lesion detection and differentiation of liver metastases from cysts (mean 0.955, 0.999) were higher than those of MDCT (mean 0.925, 0.982), but not statistically significantly so (P > 0.05). Sensitivity of SPIO-enhanced MR imaging with regard to the detection of liver metastases (mean 94.5%) was significantly higher than that of MDCT (mean 80.0%) (P < 0.05). SPIO-enhanced MR imaging and 16-MDCT showed similar diagnostic accuracies for detection and differentiation of liver metastases from cysts, but sensitivity of SPIO-enhanced imaging in the detection of liver metastases was superior to that of 16-MDCT.

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Section: Discussionmentioning

confidence: 84%

Detection and characterization of liver metastases: 16--slice multidetector computed tomography versus superparamagnetic iron oxide-enhanced magnetic resonance imaging

Kim

Hwang

et al. 2006

Eur Radiol

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“…The limited attenuation difference that can often occur between hepatic lesions and the surrounding normal liver tissue [12] may compromise dose optimisation since high exposures aimed at reducing image noise and maximising low-contrast resolution may be required [13].…”

Section: Advances In Knowledgementioning

confidence: 99%

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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“…Nevertheless, tradeoffs between axial resolution and noise can be envisaged to optimize CT protocols for an envisaged clinical application 7. Previous studies have tested various protocols to find the slice thickness,8, 9, 10 slice spacing,11, 12 or interpolation algorithm13 that would give the best compromise between z ‐axial resolution and noise. Although the physical relationships between axial resolution and noise in CT are long known, the stochastic influence of z ‐axial PVE on the contrast of small objects has never been taken into account.…”

Section: Introductionmentioning

confidence: 99%

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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Detection of liver metastases under 2 cm: comparison of different acquisition protocols in four row multidetector-CT (MDCT)

Cited by 47 publications

References 28 publications

Detection and characterization of liver metastases: 16--slice multidetector computed tomography versus superparamagnetic iron oxide-enhanced magnetic resonance imaging

Detection and characterization of liver metastases: 16--slice multidetector computed tomography versus superparamagnetic iron oxide-enhanced magnetic resonance imaging

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

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

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