Ultra-low-dose chest computed tomography without anesthesia in the assessment of pediatric pulmonary diseases / Tomografia computadorizada de tórax de ultrabaixa dosagem sem anestesia naavaliação de doenças pulmonares pediátricas

Abstract Objective To evaluate the feasibility of using ultra-low-dose computed tomography of the chest with iterative reconstruction without anesthesia for assessment of pulmonary diseases in children. Methods This prospective study enrolled 86 consecutive pediatric patients (ranging from 1 month to 18 years) that underwent ultra-low-dose computed tomography due to suspicion of pulmonary diseases, without anesthesia and contrast. Parameters used were: 80 kVp; 15-30 mA; acquisition time, 0.5 s; and pitch, 1.375. The adaptive statistical iterative reconstruction technique was used. Subjective visual evaluation and quantitative assessment of image quality were done using a 5-point scale in 12 different structures of the chest. Results Mean age was 66 months (interquartile range, 16-147). Final diagnosis was performed in all exams, and 44 (51.2%) were diagnosed with cystic fibrosis, 27 (31.4%) with bronchiolitis obliterans, and 15 (17.4%) with congenital pulmonary airways malformations. Diagnostic quality was achieved in 98.9%, of which 82.6% were considered excellent and 16.3% were slightly blurred but did not interfere with image evaluation. Only one case (1.2%) presented moderate blurring that slightly compromised the image, and previous examinations demonstrated findings compatible with bronchiolitis obliterans. Mean effective radiation dose was 0.39 ± 0.15 mSv. Percentages of images with motion artifacts were 0.3% for cystic fibrosis, 1.3% for bronchiolitis obliterans, and 1.1% for congenital pulmonary airways malformations. Conclusion Chest ultra-low-dose computed tomography without sedation or anesthesia delivering a sub-millisievert dose can provide image quality to allow identification of common pulmonary anatomy and diseases.

Resumo Objetivo Avaliar a viabilidade do uso de tomografia computadorizada com ultrabaixa dose com reconstrução iterativa sem anestesia para avaliação de doenças pulmonares em crianças. Métodos Este estudo prospectivo envolveu 86 pacientes pediátricos consecutivos (um mês a 18 anos) submetidos à tomografia computadorizada com ultrabaixa dose por suspeita de doenças pulmonares, sem anestesia e contraste. Os parâmetros utilizados foram: 80 kVp; 15-30 mA; tempo de aquisição, 0,5 s; e pitch de 1,375. Foi utilizada a técnica de reconstrução estatística adaptativa iterativa. A avaliação visual subjetiva e a avaliação quantitativa da qualidade da imagem foram feitas com uma escala de 5 pontos em 12 estruturas do tórax. Resultados A média de idade foi de 66 meses (intervalo interquartil, 16-147). O diagnóstico final foi feito em todos os exames e 44 (51,2%) foram diagnosticados com fibrose cística, 27 (31,4%) com bronquiolite obliterante e 15 (17,4%) com malformação congênita pulmonar das vias aéreas. A qualidade diagnóstica foi alcançada em 98,9% dos casos, dos quais 82,6% foram considerados excelentes e 16,3% alteração leve na definição, mas isso não interferiu na avaliação da imagem. Apenas um caso (1,2%) apresentou alteração moderada na definição, comprometeu discretamente a imagem, e exames prévios demonstraram achados compatíveis com bronquiolite obliterante. A dose de radiação média efetiva foi de 0,39 ± 0,15 mSv. As porcentagens de imagens com artefatos de movimento foram de 0,3% para fibrose cística, 1,3% para bronquiolite obliterante e 1,1% para malformação congênita pulmonar das vias aéreas. Conclusão É possível realizar a tomografia computadorizada com ultrabaixa dose torácica sem sedação ou anestesia, administrando uma dose de submilisievert, com qualidade de imagem suficiente para a identificação pulmonar anatômica e de doenças pulmonares comuns.

The safety and effectiveness of 0.16 mg bevacizumab plus or minus additional laser photocoagulation in the treatment of retinopathy of prematurity

Purpose: Retinopathy of prematurity (ROP) is the leading cause of preventable blindness in premature infants. Antivascular endothelial growth factor (anti-VEGF) therapy has been used increasingly in treatment as a pharmacological alternative to laser therapy. In this study, we evaluate the results of low-dose anti-VEGF treatments. Methods: Design: Retrospective--observational study. Infants who had been evaluated for ROP disease between February 2016 and February 2017 were assessed. We retrospectively reviewed the ROP stages, treatment results, and complications. Laser photocoagulation (LPC) and intravitreal bevacizumab (0.16 mg IVB) were used for treatment and fundus fluorescein angiography (FFA) was also performed in some of the cases. Results: IVB was applied to 43 infants. A macular hole was seen in one infant's eye after IVB. LPC was applied to avascular areas in 21 infants. In three patients, persistence of the disease was observed after administration of a low dose of IVB. Additional LFK was performed in these patients. None of the infants who received LPC had any complications. Conclusion: IVB is increasingly becoming the first-line treatment for ROP. For severe ROP, 0.16 mg IVB is effective. Using LPC to treat avascular areas after 70 weeks' gestational age (GA) may decrease the risk of late recurrence and appears to be a safe treatment to use.

Feasibility of ultra low-dose coronary computed tomography angiography

There is an urgent need to develop new protocols to reduce radiation dose of coronary computed tomography angiography (CTA). The aim of this pilot study was to demonstrate the feasibility of an ultra-low dose CTA scanning.

Ultra-Low-Dose Chest CT in Patients with Neutropenic Fever and Hematologic Malignancy: Image Quality and Its Diagnostic Performance / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The aim of this study was to evaluate the image quality of ultra-low-dose computed tomography (ULDCT) and its diagnostic performance in making a specific diagnosis of pneumonia in febrile neutropenic patients with hematological malignancy. MATERIALS AND METHODS: ULDCT was performed prospectively in 207 febrile neutropenic patients with hematological malignancy. Three observers independently recorded the presence of lung parenchymal abnormality, and also indicated the cause of the lung parenchymal abnormality between infectious and noninfectious causes. If infectious pneumonia was considered the cause of lung abnormalities, they noted the two most appropriate diagnoses among four infectious conditions, including fungal, bacterial, viral, and Pneumocystis pneumonia. Sensitivity for correct diagnoses and receiver operating characteristic (ROC) curve analysis for evaluation of diagnostic accuracy were calculated. Interobserver agreements were determined using intraclass correlation coefficient. RESULTS: Of 207 patients, 139 (67%) had pneumonia, 12 had noninfectious lung disease, and 56 had no remarkable chest computed tomography (CT) (20 with extrathoracic fever focus and 36 with no specific disease). Mean radiation expose dose of ULDCT was 0.60+/-0.15 mSv. Each observer regarded low-dose CT scans as unacceptable in only four (1.9%), one (0.5%), and three (1.5%) cases of ULDCTs. Sensitivity and area under the ROC curve in making a specific pneumonia diagnosis were 63.0%, 0.65 for reader 1; 63.0%, 0.61 for reader 2; and 65.0%, 0.62 for reader 3; respectively CONCLUSION: ULDCT, with a sub-mSv radiation dose and acceptable image quality, provides ready and reasonably acceptable diagnostic information for pulmonary infection in febrile neutropenic patients with hematologic malignancy

Evaluation of Ultra-Low Dose CT in the Diagnosis of Pediatric-Like Fractures Using an Experimental Animal Study

OBJECTIVE: The aim of this prospective study was to evaluate the performance of ultra-low dose CT for the diagnosis of pediatric-like fractures and ascertain the lowest dose level sufficient for diagnostics. MATERIALS AND METHODS: Fifty-one bones of young pig cadavers were artificially fractured and subsequently examined by using a 64 multi-detector CT with 36 various dose levels down to a dose comparable with that of X-rays. Two pediatric radiologists analysed the CT scans according to the presence or absence of a fracture, determination of the fracture type and the displacement as well as the diagnostic certainty. For each dose protocol, a success rate for the correct determination of the above-mentioned CT analyses was calculated. A success rate of at least 95% was considered sufficient for diagnostics. RESULTS: All but the lowest dose levels were sufficient to identify the fracture. Only the two lowest dose levels were insufficient to detect the fracture type. All dose levels were adequate for the identification of the displacement. The lowest dose level sufficient for diagnostics was 120 kVp, 11 mAs, and pitch 1.5, with a CTDIvol of 10% of a standard dose and an effective dose three times as large as that of X-rays. CONCLUSION: Ultra-low dose CT provides the feasibility of a significant dose reduction, still allowing sufficient diagnostics of pediatric-like fractures.

The Evaluation for Attenuation Map using Low Dose in PET/CT System / 의학물리

The current PET/CT system with high quality CT images not only increases diagnostic value by providing anatomic localization, but also shortens the acquisition time for attenuation correction than primary PET system. All commercially available PET/CT system uses the CT scan for attenuation correction instead of the transmission scan using radioactive source such as 137Cs, 68Ge. However the CT scan may substantially increase the patient dose. The purpose of this study was to evaluate quality of PET images reconstructed by CT attenuation map using various tube currents. In this study, images were acquired for 3D Hoffman brain phantom and cylindrical phantom using GE DSTe PET/CT system. The emission data were acquired for 10 min using phantoms after injecting 44.03 MBq of 18F-FDG. The CT images for attenuation map were acquired by changing tube current from 10 mA to 95 mA with fixed exposure time of 8 sec and fixed tube voltage of 140 kVp. The PET images were reconstructed using these CT attenuation maps. Image quality of CT images was evaluated by measuring SD (standard deviation) of cylindrical phantom which was filled with water and 18F-FDG solution. The PET images were evaluated by measuring the activity ratio between gray matter and white matter in Hoffman phantom images. SDs of CT images decrease by increasing tube current. When PET images were reconstructed using CT attenuation maps with various tube currents, the activity ratios between gray matter and white matter of PET images were almost same. These results indicated that the quality of the PET images using low dose CT data were comparable to the PET images using general dose CT data. Therefore, the use of low dose CT is recommended than the use of general dose CT, when the diagnostic high quality CT is not required. Further studies may need to be performed for other system, since this study is limited to the GE DSTe system used in this study.