Objective To determine the difference in CT values and image quality of abdominal CT images reconstructed by filtered back-projection (FBP), hybrid iterative reconstruction (IR), and deep learning... Show moreObjective To determine the difference in CT values and image quality of abdominal CT images reconstructed by filtered back-projection (FBP), hybrid iterative reconstruction (IR), and deep learning reconstruction (DLR). Methods PubMed and Embase were systematically searched for articles regarding CT densitometry in the abdomen and the image reconstruction techniques FBP, hybrid IR, and DLR. Mean differences in CT values between reconstruction techniques were analyzed. A comparison between signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of FBP, hybrid IR, and DLR was made. A comparison of diagnostic confidence between hybrid IR and DLR was made. Results Sixteen articles were included, six being suitable for meta-analysis. In the liver, the mean difference between hybrid IR and DLR was - 0.633 HU (p = 0.483, SD +/- 0.902 HU). In the spleen, the mean difference between hybrid IR and DLR was - 0.099 HU (p = 0.925, SD +/- 1.061 HU). In the pancreas, the mean difference between hybrid IR and DLR was - 1.372 HU (p = 0.353, SD +/- 1.476 HU). In 14 articles, CNR was described. In all cases, DLR showed a significantly higher CNR. In 9 articles, SNR was described. In all cases but one, DLR showed a significantly higher SNR. In all cases, DLR showed a significantly higher diagnostic confidence. Conclusions There were no significant differences in CT values reconstructed by FBP, hybrid IR, and DLR in abdominal organs. This shows that these reconstruction techniques are consistent in reconstructing CT values. DLR images showed a significantly higher SNR and CNR, compared to FBP and hybrid IR. Show less
In this thesis several aspects on the diagnosing and management of patients with acute abdominal pain are investigated. 1; The efficacy and safety of standard outpatient re-evaluation for patients... Show moreIn this thesis several aspects on the diagnosing and management of patients with acute abdominal pain are investigated. 1; The efficacy and safety of standard outpatient re-evaluation for patients not admitted to the hospital after emergency department evaluation for acute abdominal pain. 2; The use of a diagnostic strategy for patients clinically suspected to have appendicitis incorporating non-invasive modalities such as clinical evaluation, routine ultrasound and clinical re-evaluation, and a minimal use of complementary CT or laparoscopy. 3; The possibility to clinically differentiate between children with acute appendicitis and those with acute mesenteric lymphadenitis. 4; The value of secondary signs during the ultrasonographic evaluation of children with suspected appendicitis. 5; The impact of radiological imaging on diagnostic accuracy and clinical decision making for patients with acute colonic diverticulitis. 6; A systematic review on laparoscopic peritoneal lavage for patients with peritonitis due to perforated colonic diverticulitis. Show less
This thesis describes five ultrasonogaphic studies in children with abdominal pain. The normal appendix can be visualized by ultrasound in 82% of the children without abdominal complaints,... Show moreThis thesis describes five ultrasonogaphic studies in children with abdominal pain. The normal appendix can be visualized by ultrasound in 82% of the children without abdominal complaints, according to the first study. In cases of non-depiction of the appendix in children with a clinical suspicion of appendicitis, the ultrasonographic presence of secondary signs of appendicitis is a strong indicator of this diagnosis. In the absence of these ultrasonographic signs acute appendicitis can be ruled out. The third study shows that increased renal cortex echogenicity in children with acute illness is a transient feature and does not necessarily indicate renal disease. It should alert the radiologist to search the abdomen more thoroughly for a cause of the acute illness, such as appendicitis. The fourth study showed that ultrasonography can differentiate between ileoileal and ileocolic intussusceptions. The diameter and the length of the intussusception are the main criteria. Finally, the last study shows no relation between enlarged mesenteric lymph nodes and parasitic intestinal infections in children with recurrent abdominal pain. In addition, this study shows organic abnormalities in less than 5% of the children with recurrent abdominal pain at ultrasound. Show less
