CT scan can be used to show the anatomical and pathological evaluation of Mastoid bones where an X-ray across it to create a cross-sectional image with an advanced computer. This imaging modality allows the radiologist to look at different levels of the bone ridge behind the ear. In our hospital, this procedure needs to be improved. Radiographer could make optimization by adjusting windows and developing kernel to maintain the image quality. This study aimed to obtain the optimum image of Mastoid bones, using variations of window and kernel reconstruction. The study was descriptive quantitative with an experimental approach. It resulted in eight images of two windowing levels (sinus and inner ear) and four kernel variations (smooth, medium, sharp, and ultra-sharp). Three radiologists evaluated the injury, bleedin, and soft tissue abnormalities images. The result showed that all window settings are acceptable. Kernel reconstructions have no different anatomical image information in soft tissue, Internal Auditory Canal, and External Auditory Canal. There is a difference for overall anatomical information of Mastoid bones (p value<0.05). Highest values of mean rank are obtained from sharp and ultra-sharp. Our recommendations are using the H.20s smooth kernel for soft tissue abnormalities and H.70s sharp kernel for fracture and bleeding cases.
Introduction
Deep learning image reconstruction (DLIR) is a very recent image reconstruction method that is already available for commercial use. We evaluated the quality of DLIR images and compared it to the quality of images from the latest adaptive statistical iterative reconstruction (ASIR-V) algorithm in terms of noise-power spectrum (NPS) and modulation-transfer function (MTF).
Methods
We scanned a Revolution QA phantom (GE Healthcare, USA) and a 20 cm water phantom (GE Healthcare, USA) with our 512 multi-slice computed tomography (CT) scanner. Images of the tungsten wire within the Revolution QA phantom were reconstructed with a 50 mm field of view (FOV). The images were reconstructed with various ASIR-V strengths (i.e. 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100%) and DLIRs (i.e. low, medium, and high) to assess the MTF. The images from the 20 cm water phantom were reconstructed with the same configuration to assess the NPS.
Results
The MTF was similar for both reconstruction algorithms of DLIR and ASiR-V. The peak frequency (fp) of the DLIR low was comparable to that from ASIR-V at 50, 60, 70%; the DLIR medium was comparable to ASIR-V at 80%; and the DLIR high was comparable to ASIR-V at 100%. The average frequency (fA) of the DLIR low was comparable to that from ASIR-V at 40%; the DLIR medium was comparable to ASIR-V at 50%; and the DLIR high was comparable to ASIR-V at 70%. Both the DLIR and ASIR-V were able to reduce noise, but they had a different texture.
Conclusions
The noise in the DLIR images was more homogenous at high and low frequencies, while in the ASIR-V images, the noise was more concentrated at high frequencies. The MTF was similar for both reconstruction algorithms. The DLIR method showed a better noise reduction than the ASIR-V reconstruction.
Algoritma Filtered Back Projection (FBP) telah menjadi algoritma standar untuk rekonstruksi citra dalam computed tomography (CT) selama bertahun-tahun, tetapi algoritma ini menciptakan kemungkinan artefak dan peningkatan noise gambar yang mencolok ketika dosis radiasi dikurangi secara berlebihan. Dengan kemajuan teknologi dan peningkatan kapasitas komputasi, algoritma Adaptive Statistical Iterative Reconstruction (ASIR) telah muncul kembali sebagai alternatif potensial. Tujuan dari tinjauan ini adalah untuk menetapkan apakah secara umum bahwa algoritma ASIR mengurangi dosis radiasi dan meningkatkan kualitas gambar di CT dibandingkan dengan algoritma FBP. Tinjauan sistematis literatur dari 2011 hingga 2022 dilakukan menggunakan Elsevier, Google Scholar, Pubmed, AJR, dan Science Direct, Physica Medica dan Korean Journal of Radiology. Sebanyak 11 artikel dikategorikan sebagai artikel sinopsis atau studi klinis evaluasi kinerja. Hasilnya menunjukkan bahwa penggunaan algoritma IR mengurangi noise gambar objektif, dan setidaknya mempertahankan resolusi spasial dan deteksi kontras rendah, bahkan ketika dosis dikurangi. Kesimpulannya, secara umum bahwa algoritma ASIR dapat dengan mengurangi dosis radiasi namun harus memperhatikan level ASIR dalam meningkatkan kualitas gambar di CT dibandingkan dengan algoritma FBP.
Kata kunci: FBP; ASIR; gambar; dosis
Signal to Noise Ratio (SNR) is one of the quality control tests for most diagnostic imaging modality, including Magnetic Resonance Imaging (MRI). This study used MRI 1.5T GE Signa Creator type and head coil phantom with variations of Echo Time (TE), Repetition Time (TR), voxel volume and flip angle. 16 data images were obtained from the acquisition process. These images were analyzed using image processing software to calculate the SNR value. It results in four data distribution with the highest value of 36.98 and the lowest value of 32.64. The graphs of voxel volume versus SNR also formed four groups of data with an overall value above SNR baseline value for daily operation.
Verification of the irradiation set up is a process to ensure that the position and volume of the irradiated tumor are the same as planned. It is conducted by comparing the radiographic image information of the Treatment Planning System (TPS) with radiation therapy to be provided on the Electronic Portal Imaging Device (EPID). Existing software s on the EPID modality device in this hospital are Mosaiq and IViewGT. This study was to describe the details of the verification process and the differences between two software s in conformal radiotherapy of nasopharyngeal cancer patients. This study was a quantitative analytic study. Samples were fifty-two portal images. Data was analyzed by statistical software. The results are descriptions of the verification process, and the value of shift set up irradiation on X; Y and Z axis. There is no difference statistically between two software s. Mosaiq software is more complicated in image processing. IViewGT software has an advantage in its better simplicity but shows the same quality.
Increasing delay time between erasure and image acquisition can lead to the appearance of dark noise on the Computed Radiography (CR) imaging plate (IP). The purpose of this study is to investigate the time delay of the last erasure that can be affected in dark noise appearance of four sizes Carestream CR’s imaging plate in Radiology Laboratory of Poltekkes Kemenkes Semarang. This study used a quantitative experimental method. Each size of IP was exposed with one of Hand, Cranium, Chest, and Abdomen anthropomorphic phantom, read on CR, and left for 0 hours, 1 hour, 3 hours, 6 hours, 9 hours, 12 hours and 24 hours to produce blank images. The blank images after post-processing were evaluated with qualitative and quantitative criteria. Qualitative criteria produced uniformity images, without ghost images artifact. While quantitative criteria were determined by the exposure index value, pixel value, and pixel value standard deviation calculated by ImageJ. The results of this study showed that all of the IPs did not pass the criteria. Dark noise appeared in 0 hours after the last erasure shown from un-uniformity images, ghost images artifact, PV, and PVSD were overpassed the standard values. Dark noise has increased the time delay between last erasure and subsequent use. The imaging plate must be erased before it acquires the next images.
Brain MRI examination using contrast media can improve detection of brain metastases. The fat saturation technique is recommended to suppress large amounts of signals from fat and improve contrast enhancement. The purpose of this study was to determine the differences in SNR values and anatomical image information on post-contrast Brain examination between T1-Weighted Spin Echo and T1-Weighted SPIR sequences in metastatic cases. The study is a quantitative experimental. The results of the study were obtained based on Radiologist’s assessment and SNR measurement from gray matter, white matter, ventricular, cerebrospinal fluid, and pathological lesions. Analysis of this research data using the Wilcoxon sign rank test statistic. There is a significant difference between the SNR value of the two sequences. The results in anatomical information showed no difference. T1W sequence Spin echo had better visualization in gray matter, and white matter, while T1W SPIR sequence had advanced in pathological lesions appearance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.