Quantitative Image Quality Comparison of Reduced- and Standard-Dose Dual-Energy Multiphase Chest, Abdomen, and Pelvis CT

Abstract

We present a new image quality assessment method for determining whether reducing radiation dose impairs the image quality of computed tomography (CT) in qualitative and quantitative clinical analyses tasks. In this Institutional Review Board-exempt study, we conducted a review of 50 patients (male, 22; female, 28) who underwent reduced-dose CT scanning on the first follow-up after standard-dose multiphase CT scanning. Scans were for surveillance of von Hippel-Lindau disease (N = 26) and renal cell carcinoma (N = 10). We investigated density, morphometric, and structural differences between scans both at tissue (fat, bone) and organ levels (liver, heart, spleen, lung). To quantify structural variations caused by image quality differences, we propose using the following metrics: dice similarity coefficient, structural similarity index, Hausdorff distance, gradient magnitude similarity deviation, and weighted spectral distance. Pearson correlation coefficient and Welch 2-sample t test were used for quantitative comparisons of organ morphometry and to compare density distribution of tissue, respectively. For qualitative evaluation, 2-sided Kendall Tau test was used to assess agreement among readers. Both qualitative and quantitative evaluations were designed to examine significance of image differences for clinical tasks. Qualitative judgment served as an overall assessment, whereas detailed quantifications on structural consistency, intensity homogeneity, and texture similarity revealed more accurate and global difference estimations. Qualitative and quantitative results indicated no significant image quality degradation. Our study concludes that low(er)-dose CT scans can be routinely used because of no significant loss in quantitative image information compared with standard-dose CT scans.

Diagnostic Reference Level of Radiation Dose and Image Quality among Paediatric CT Examinations in A Tertiary Hospital in Malaysia

“…In spite of that, multiple studies had stated that it was challenging to balance radiation exposure and image quality due to variances in the patients' body habitus [33,34]. Therefore, adjustments of CT scanning parameters should be made in the optimization processes, particularly when pediatric patients were involved.…”

Deep learning image reconstruction algorithm for abdominal multidetector CT at different tube voltages: assessment of image quality and radiation dose in a phantom study

“…Interestingly, all of the reported SSIM indices in our study were relatively high (> 0.99 on a scale from 0 to 1) even for low-dose scanning. Although it was a small absolute difference, there was a certain directionality to the SSIM index, and considering the previous literature [22,41], such a small difference in SSIM index might be regarded as a clinically relevant difference. Based on the overall image quality results in our study, when DLIR is used, the tube current should be set at 200 mA to lower the scan voltage to 100kVp or less, and the scan voltage should be set at 120kVp to lower the tube current to 100 mA, to obtain images of considerable quality compared to that of a full-dose scan.…”

“…Several studies have evaluated the image quality of CT with DLIR algorithm by assessing various indicators including the noise, CNR, artifacts, spatial resolution, and diagnostic acceptability of CT images [10,[12][13][14][15]39]. Although a few studies tried to assess the overall image quality quantitatively [22,40,41], to the best of our knowledge, there has been no study evaluating the overall image quality represented by objective indices in terms of abdominal CT or DLIR algorithm yet. In our study, we focused on the clinically relevant application of SSIM, which is a numerical indicator for perceived image quality, in clinically available CT reconstruction techniques.…”

Cumulative Radiation Exposures from CT Screening and Surveillance Strategies for von Hippel-Lindau–associated Solid Pancreatic Tumors

“…Comparison of cumulative radiation exposure on the basis of diameter-based versus VHL genotype and tumor diameter-based PNET surveillance algorithm were performed by using an of Health Clinical Center (L.R.F., with 30 years of experience, and W.K.). Compared with the threephase CT protocol, the dual-energy VNC protocol halves the radiation exposure by eliminating the precontrast phase and decreasing the tube current with the use of iterative reconstruction (18,19 ). Equivalent organ doses and effective dose for each single scan were estimated by radiation scientists (C. Lee, with 14 years of experience, and N.J.) on the basis of volume CT dose index values extracted from the Digital Imaging and Communications in Medicine headers.…”