Low kilovoltage and low contrast volume neck CT protocol using iterative reconstruction techniques: A comparison with standard dose protocol

2021 ◽  
pp. 109935
Author(s):  
Shubham Chhetri ◽  
Saikiran Pendem ◽  
J.L. Bharath ◽  
Priyanka
Keyword(s):  
Iterative Reconstruction ◽  
Standard Dose ◽  
Low Contrast ◽  
Contrast Volume ◽  
Ct Protocol ◽  
Low Kilovoltage

Implication of applying iterative reconstruction on Low Contrast Detectability in CT brain examination

2021 ◽  
pp. 109676
Author(s):  
Z. Kayun ◽  
M.K.A. Karim ◽  
N.A. Muhammad ◽  
O.B. Aljewaw ◽  
C.M. Tsuey ◽  
...  
Keyword(s):  
Iterative Reconstruction ◽  
Low Contrast ◽  
Ct Brain ◽  
Brain Examination

scholarly journals Comparison of low-contrast detectability between uniform and anatomically realistic phantoms—influences on CT image quality assessment

2021 ◽  
Author(s):  
Juliane Conzelmann ◽  
Ulrich Genske ◽  
Arthur Emig ◽  
Michael Scheel ◽  
Bernd Hamm ◽  
...  
Keyword(s):  
Image Quality ◽  
Quality Assessment ◽  
Dose Reduction ◽  
Iterative Reconstruction ◽  
Image Quality Assessment ◽  
Lesion Detection ◽  
Detection Accuracy ◽  
Test Environment ◽  
Low Contrast ◽  
Dose Effects

Abstract Objectives To evaluate the effects of anatomical phantom structure on task-based image quality assessment compared with a uniform phantom background. Methods Two neck phantom types of identical shape were investigated: a uniform type containing 10-mm lesions with 4, 9, 18, 30, and 38 HU contrast to the surrounding area and an anatomically realistic type containing lesions of the same size and location with 10, 18, 30, and 38 HU contrast. Phantom images were acquired at two dose levels (CTDIvol of 1.4 and 5.6 mGy) and reconstructed using filtered back projection (FBP) and adaptive iterative dose reduction 3D (AIDR 3D). Detection accuracy was evaluated by seven radiologists in a 4-alternative forced choice experiment. Results Anatomical phantom structure impaired lesion detection at all lesion contrasts (p < 0.01). Detectability in the anatomical phantom at 30 HU contrast was similar to 9 HU contrast in uniform images (91.1% vs. 89.5%). Detection accuracy decreased from 83.6% at 5.6 mGy to 55.4% at 1.4 mGy in uniform FBP images (p < 0.001), whereas AIDR 3D preserved detectability at 1.4 mGy (80.7% vs. 85% at 5.6 mGy, p = 0.375) and was superior to FBP (p < 0.001). In the assessment of anatomical images, superiority of AIDR 3D was not confirmed and dose reduction moderately affected detectability (74.6% vs. 68.2%, p = 0.027 for FBP and 81.1% vs. 73%, p = 0.018 for AIDR 3D). Conclusions A lesion contrast increase from 9 to 30 HU is necessary for similar detectability in anatomical and uniform neck phantom images. Anatomical phantom structure influences task-based assessment of iterative reconstruction and dose effects. Key Points • A lesion contrast increase from 9 to 30 HU is necessary for similar low-contrast detectability in anatomical and uniform neck phantom images. • Phantom background structure influences task-based assessment of iterative reconstruction and dose effects. • Transferability of CT assessment to clinical imaging can be expected to improve as the realism of the test environment increases.

Dual-energy MDCT: Comparison of pulmonary artery enhancement on dedicated CT pulmonary angiography, routine and low contrast volume studies

2011 ◽  
Vol 79 (2) ◽  
pp. e11-e17 ◽  
Author(s):  
Myrna C.B. Godoy ◽  
Samantha L. Heller ◽  
David P. Naidich ◽  
Bernard Assadourian ◽  
Christianne Leidecker ◽  
...  
Keyword(s):  
Pulmonary Artery ◽  
Pulmonary Angiography ◽  
Dual Energy ◽  
Ct Pulmonary Angiography ◽  
Low Contrast ◽  
Contrast Volume

scholarly journals Low Dose Computed Tomography in Diagnosis of Ureteric Calculus in Obese Patients

2020 ◽  
Vol 9 (1) ◽  
pp. 27-31
Author(s):  
Mahesh Gautam ◽  
Aziz Ullah ◽  
Manish Raj Pathak
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Low Dose ◽  
Standard Dose ◽  
Reconstruction Technique ◽  
Obese Patients ◽  
Low Dose Computed Tomography ◽  
Effective Radiation

Background: Standard dose computed tomography is standard imaging modality in diagnosis of urolithiasis. The introduction of low dose techniques results in decrease radiation dose without significant change in image quality. However, the image quality of low dose computed tomography is affected by skin fold thickness and subcutaneous abdominal adipose tissue. The aim of this study to evaluate stone location, size, and density using low dose computed tomography compared with standard dose computed tomography in obese population. Material and Methods: This non-randomized non-inferiority trial includes 120 patient having BMI≥25kg/m2 with acute ureteric colic. The low dose and standard dose computed tomography were performed accordingly. Effective radiation doses were calculated from dose-length product obtained from scan report using conversion factor of 0.015. The images were reconstructed using iterative reconstruction algorithm. Effective dose, number and size of stone, Hounsfield Unit value of stone and image quality was assessed. Results: Stones were located in 69 (57.5%) in right and 51 (42.5%) in left ureter. There was no statistical difference in mean diameter, number and density of stones in low dose as compared with standard dose. The radiation dose was significantly lower with low dose. (3.68 mSv) The delineation of the ureter, outline of the stones and image quality in low dose was overall sufficient for diagnosis. No images of low dose scan were subjectively rated as non-diagnostics. Conclusion: Low dose computed tomography with iterative reconstruction technique is as effective as standard dose in diagnosis of ureteric stones in obese patients with lower effective radiation dose.

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