Model-Based Iterative Reconstruction Enables the Evaluation of Thin-Slice Computed Tomography Images Without Degrading Image Quality or Increasing Radiation Dose

Abstract

Computed tomography (CT) is one of the most important modalities in a radiological department. This technique produces images that enables radiological reports with high diagnostic confidence, but may provide an elevated radiation dose to the patient. The radiation dose can be reduced by using advanced image reconstruction algorithms. This study was performed on a Brilliance iCT, equipped with iDose 4 iterative reconstruction and an iterative model-based reconstruction (IMR) method. The purpose was to investigate the effect of reduced slice thickness combined with an IMR method on image quality compared with standard slice thickness with iDose 4 reconstruction. The results of objective and subjective image quality evaluations showed that a thinner slice combined with IMR can improve the image quality and reduce partial volume artefacts compared with the standard slice thickness with iDose 4 . In conclusion, IMR enables reduction of the slice thickness while maintaining or even improving image quality versus iDose 4 .

Assessment of image quality in abdominal computed tomography: Effect of model-based iterative reconstruction, multi-planar reconstruction and slice thickness on potential dose reduction

“…A slight improvement in image quality for three out of five criteria in favor of the higher strength at 1 mm slice thickness was observed, when comparing the two algorithm strengths at same slice thickness and some dose reduction is possible. This could be attributed to the reduction in partial volume averaging [14] and/or increase in quantum noise in thinner slices [27]. Contrary to our study, two studies have reported retained image quality with thin slices for the higher strength of another MBIR [14,15].…”

“…This could be attributed to the reduction in partial volume averaging [14] and/or increase in quantum noise in thinner slices [27]. Contrary to our study, two studies have reported retained image quality with thin slices for the higher strength of another MBIR [14,15]. Both these studies evaluated effect of slice thickness using an iterative model-based reconstruction (Iterative Model Reconstruction (IMR), Philips) in brain CT and abdominal phantom respectively.…”

“…To maintain the high spatial resolution and minimize partial volume averaging effects, CT images are acquired with thinnest detector configuration available according to the ALARA principle [13]. Various MBIR studies have evaluated the effect of variation in slice thickness on image quality [10,14,15]. In addition, MPR provides improved visualization of abdominal structures and increases the diagnostic confidence [16].…”

A simple method for low-contrast detectability, image quality and dose optimisation with CT iterative reconstruction algorithms and model observers

“…iDOSE provided, therefore, a similar image resolution to that obtained with FBP at significantly higher mAs values. Our results represent, therefore, a valuable confirmation that the use of IR algorithms preserves the spatial resolution while reducing mAs [ 21 ], except at very low tube load (i.e. < 50 mAs) where a very small decrease in spatial resolution was found [ 19 ].…”

Evaluation of an iterative model-based reconstruction of pediatric abdominal CT with regard to image quality and radiation dose

“…There is a balance between the slice thickness and the amount of noise in the image. A previous study (21) showed that IMR could be used for analyzing images at thinner slice thicknesses, which improved image quality by suppressing the partial volume effect. Currently, IMR has been introduced in some routine examination protocols for adults in our clinic and images are analyzed in thin slices.…”