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Principles of Iterative Reconstruction for Emission Tomography
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Representative results from 4D reconstruction methods are shown in Figure 20.16. There have been a number of reviews on 4D image reconstruction [28] [29] [2] that expand considerably on the outline given here.
Nuclear Medicine Imaging and Therapy
Published in Debbie Peet, Emma Chung, Practical Medical Physics, 2021
David Towey, Lisa Rowley, Debbie Peet
The image processing steps may include spatial and/or temporal filtering, region or volume of interest measurements, and 3D/4D reconstruction. Table 5.6 shows the parameters identified as optimal for whole body and SPECT imaging of the bones.
Increasing the accuracy of colorectal cancer screening
Published in Expert Review of Anticancer Therapy, 2023
Silvia Pecere, Cristina Ciuffini, Michele Francesco Chiappetta, Lucio Petruzziello, Luigi Giovanni Papparella, Cristiano Spada, Antonio Gasbarrini, Federico Barbaro
As mentioned above, colonoscopy is the main examination for the prevention of CRC. However, a percentage of patients undergo incomplete colonoscopy, refuse or cannot undergo colonoscopy. Therefore, the role of colon capsule endoscopy (CCE) and computed tomographic colonography (CTC) in CRC screening has been investigated [64]. CCE is a wireless, single-use pill-sized camera that, once swallowed by the patients and overcome the ileo-cecal valve, allows the visualization of the colonic mucosa. Bowel preparation for CCE is not only aimed to wall washing (polyethylene glycol) but also to promote capsule progression in the lumen (sodium phosphate); adequate cleansing level is reached in about 80% of patients and its crucial given the impossibility of cleaning during the examination. It has the advantage to be a safe, painless, and minimally invasive technique, that does not need sedation or insufflation and is better tolerated by patients [65]. Several studies investigating accuracy of second-generation CCE (CCE-2) in detecting colorectal neoplasia found sensitivity and specificity ranging from 79% to 89% and from 64% to 97%, respectively, in average risk population [66–69]. CTC on the other hand represent a noninvasive technique that enables the visualization of the entire colonic mucosa through a 3D or 4D reconstruction [70]. It also allows an evaluation of extracolonic structures. CTC is safe, avoiding the risk related to sedation and intubation [71]. Moreover, since low dose of radiation are used, radiation-related cancer risk is outweighed by potential benefit of the exam [72]. According to a recent meta-analysis by Lin et al., evaluating the accuracy of screening tests, CTC sensitivity and specificity were 89% and 94% for adenomas ≥10 mm and 86% and 88% for adenomas ≥6 mm, respectively [15]. Detection of lesions ≤6 mm with CTC is unreliable and is considered not clinically relevant [73]. Currently, European Society of Gastrointestinal Endoscopy (ESGE) and European Society of Gastrointestinal and Abdominal Radiology (ESGAR) guidelines recommend CTC as a CRC screening strategy option in absence of an organized FIT-based screening program while dont suggest CCE as a first-line screening test. When colonoscopy is unfeasible or contraindicated in patients with alarm symptoms, only CTC is recommended as an equally effective alternative. CCE can be considered alongside of CTC in case of unfeasible or contraindicated colonoscopy in patients without alarm symptoms. Finally, ESGE and ESGAR recommend the execution of CTC after incomplete colonoscopy but, in case of non-neoplastic stricture, CCE can be considered as alternative [64].