Evaluation of the Application of Orthopedic Metal Artifact Reduction and Iterative Reconstruction Algorithms in CT Imaging of Hip Prostheses
Date
2021-05-28
Authors
Omarah Naser Saed AbdAlqader
عماره ناصر سعيد عبد القادر
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Publisher
Al-Quds University
Abstract
The CT imaging of metal hip prosthesis causes metal-related artifacts reducing the overall image quality and clinical value of CT. This study aims to an evaluation of using orthopedic metal artifact reduction (O-MAR) technique and iterative model-based reconstruction (IMR) in CT imaging of bilateral total hip prostheses in a pelvis phantom. The fabricated pelvis phantom has four major components, pelvis bones, muscle, fat, and vascular structures, and was made using different concentrations of respectively calcium sulfate, bee wax, agarose powder, and Iohexol. Two types of hip prosthesis were used total hip and Austen Moore prosthesis. Different types of algorithms, filtered back projection (FBP), iDose4, and IMR with different Kilo-Voltage peak (kVps) settings at 80, 100, 120, and 140, combined with O-MAR were applied on this phantom. The image quality criteria were CT number, noise, and signal to noise ratio (SNR) and were analyzed by five regions of interest (ROIs), while regions R1 and R5 were the primary focusing. The five RIOs representing the following anatomy (right common iliac artery, left common iliac artery, right gluteus medius muscle, fat, and urinary bladder) respectively from R1 – R5. Without the prosthesis, results showed that IMR resulted in lower CT number, noise values, and increased SNRs relative to FBP and iDose4 for regions R1-R5. With the prosthesis, O-MAR improved CT-number precision for region R1 by 49% and 83% for FBP and IMR (p<0.05), relative to iDose4 by 57% without any significant changes at (p<0.05). For region R5, O-MAR improved CT-number precision by 81%, 89%, and 92% towards baseline values for respectively FBP, iDose4, and IMR (p<0.05). Also, O-MAR was most efficient in minimizing noise when integrated with IMR with corrections in the noise in R5 with 79 %, 90 %, and 92 % for respectively FBP, iDose4, and IMR (p<0.05). . Additionally, O-MAR was most effective in correcting SNR deviations when integrated with IMR with absolute SNR corrections in region R5 with 29 ± 1 and 43 ± 4 for FBP and IMR (p<0.05), compared to iDose4 by 37 ± 7 without any significant
changes (p>0.05). For region R1, O-MAR improves SNR corrections by 5 ± 1, 23 ± 5,
and 42 ± 9 for respectively FBP, iDose4, and IMR (p<0.05). O-MAR paired with IMR
revealed an HU correction for region R5 of 90%, 90%, 93%, and 93% for respectively
80, 100, 120, and 140-kVp results. Noise was corrected for with 92%, 91%, 92% and
92% for respectively 80, 100, 120 and 140-kVp results. SNR corrections were 37%,
iv
38%, 46% and 52% for respectively 80, 100, 120 and 140-kVp results. For region R1, O-MAR combined with IMR showed an average HU correction of 90%, 68%, 81%, and 93% for respectively 80, 100, 120, and 140-kVp results. Noise was corrected with 89%, 88%, 90% and 89% for respectively 80, 100, 120 and 140-kVp results. SNR corrections were 55%, 42%, 38% and 34% for respectively 80, 100, 120 and 140-kVp results. In conclusion, O-MAR decreases the appearance of metal artifacts using iDose4 and is most efficient in severe artifacts when used in combination with 140-kVp and IMR. CT imaging of a bilateral total hip prosthesis phantom, using IMR together with O-MAR increases image quality by significantly minimizing metal artifacts, reducing noise, and enhancing CT number and SNR.
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Citation
AbdAlqader، Omarah Naser. (2021). Evaluation of the Application of Orthopedic Metal Artifact Reduction and Iterative Reconstruction Algorithms in CT Imaging of Hip Prostheses [رسالة ماجستير منشورة، جامعة القدس، فلسطين]. المستودع الرقمي لجامعة القدس.