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1.
Nat Commun ; 12(1): 1832, 2021 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-33758201

RESUMO

Synthetic glucocorticoids (GCs), one of the most effective treatments for chronic inflammatory and autoimmune conditions in children, have adverse effects on the growing skeleton. GCs inhibit angiogenesis in growing bone, but the underlying mechanisms remain unclear. Here, we show that GC treatment in young mice induces vascular endothelial cell senescence in metaphysis of long bone, and that inhibition of endothelial cell senescence improves GC-impaired bone angiogenesis with coupled osteogenesis. We identify angiogenin (ANG), a ribonuclease with pro-angiogenic activity, secreted by osteoclasts as a key factor for protecting the neighboring vascular cells against senescence. ANG maintains the proliferative activity of endothelial cells through plexin-B2 (PLXNB2)-mediated transcription of ribosomal RNA (rRNA). GC treatment inhibits ANG production by suppressing osteoclast formation in metaphysis, resulting in impaired endothelial cell rRNA transcription and subsequent cellular senescence. These findings reveal the role of metaphyseal blood vessel senescence in mediating the action of GCs on growing skeleton and establish the ANG/PLXNB2 axis as a molecular basis for the osteoclast-vascular interplay in skeletal angiogenesis.


Assuntos
Senescência Celular/efeitos dos fármacos , Células Endoteliais/metabolismo , Glucocorticoides/farmacologia , Neovascularização Fisiológica/efeitos dos fármacos , Proteínas do Tecido Nervoso/metabolismo , Osteoclastos/metabolismo , Ribonuclease Pancreático/metabolismo , Animais , Apoptose/efeitos dos fármacos , Desenvolvimento Ósseo/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Senescência Celular/genética , Células Endoteliais/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana , Humanos , Imuno-Histoquímica , Hibridização in Situ Fluorescente , Metilprednisolona/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Neovascularização Patológica , Proteínas do Tecido Nervoso/genética , Osteoclastos/efeitos dos fármacos , Osteoclastos/enzimologia , Osteogênese/efeitos dos fármacos , RNA Ribossômico/biossíntese , RNA Interferente Pequeno , Proteínas Recombinantes , Ribonuclease Pancreático/genética , Ribonuclease Pancreático/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Tomógrafos Computadorizados
2.
J Laryngol Otol ; 135(2): 125-129, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33568241

RESUMO

OBJECTIVE: This study details the intra-operative complications, and compares auditory scales post-implantation of either profoundly deaf young children with radiologically normal inner ears (group A) or children with Mondini dysplasia (group B). METHODS: A retrospective survey was carried out of 338 patients with severe to profound sensorineural hearing loss who underwent cochlear implant surgery from February 2015 to May 2017. Patients were divided into 2 groups of 27 patients each. Both groups were followed up to three years post-implantation. RESULTS: Cerebrospinal fluid ooze developed in 12 patients, and 2 patients had a cerebrospinal fluid 'gusher', one of which had to be explored within 24 hours. After implant use for one year, both groups had similar speech perception scores. CONCLUSION: The cerebrospinal fluid gusher in Mondini dysplasia should be anticipated and adequately managed intra-operatively. This study highlights the tailoring of a post-implantation rehabilitation programme according to individual needs.


Assuntos
Vazamento de Líquido Cefalorraquidiano/epidemiologia , Implante Coclear/métodos , Orelha Interna/anormalidades , Perda Auditiva Neurossensorial/cirurgia , Complicações Intraoperatórias/epidemiologia , Adulto , Estudos de Casos e Controles , Criança , Implantes Cocleares/efeitos adversos , Orelha Interna/diagnóstico por imagem , Orelha Interna/patologia , Orelha Interna/cirurgia , Perda Auditiva Neurossensorial/reabilitação , Humanos , Índia/epidemiologia , Complicações Intraoperatórias/patologia , Masculino , Estudos Retrospectivos , Percepção da Fala/fisiologia , Tomógrafos Computadorizados
3.
Med Phys ; 48(3): 1054-1063, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33325033

RESUMO

PURPOSE: Low contrast detectability (LCD) is a metric of fundamental importance in computed tomography (CT) imaging. In spite of this, its measurement is challenging in the context of nonlinear data processing. We introduce a new framework for objectively characterizing LCD with a single scan of a special-purpose phantom and automated analysis software. The output of the analysis software is a "machine LCD" metric which is more representative of LCD than contrast-noise ratio (CNR). It is not intended to replace human observer or model observer studies. METHODS: Following preliminary simulations, we fabricated a phantom containing hundreds of low-contrast beads. These beads are acrylic spheres (1.6 mm, net contrast ~10 HU) suspended and randomly dispersed in a background matrix of nylon pellets and isoattenuating saline. The task was to search for and localize the beads. A modified matched filter was used to automatically scan the reconstruction and select candidate bead localizations of varying confidence. These were compared to bead locations as determined from a high-dose reference scan to produce free-response ROC curves. We compared iterative reconstruction (IR) and filtered backpropagation (FBP) at multiple dose levels between 40 and 240 mAs. The scans at 60, 120, and 180 mAs were performed three times each to estimate uncertainty. RESULTS: Experimental scans demonstrated the feasibility of our technique. Our metric for machine LCD was the area under the exponential transform of the FROC curve (AUC). AUC increased monotonically from 0.21 at 40 mAs to 0.84 at 240 mAs. The sample standard deviation of AUC was approximately 0.02. This measurement uncertainty in AUC corresponded to a change in tube current of 4% to 8%. Surprisingly, we found that AUCs for IR were slightly worse than AUCs for FBP. While the phantom was sufficient for these experiments, it contained small air bubbles and alternative fabrication methods will be necessary for widespread utilization. CONCLUSIONS: It is feasible to measure machine LCD using a search task on a phantom with hundreds of beads and to obtain tight error bars using only a single scan. Our method could facilitate routine quality assurance or possibly enable comparisons between different protocols and scanners.


Assuntos
Algoritmos , Tomógrafos Computadorizados , Tomografia Computadorizada por Raios X , Humanos , Imagens de Fantasmas , Doses de Radiação , Interpretação de Imagem Radiográfica Assistida por Computador
5.
Artigo em Inglês | MEDLINE | ID: mdl-33167564

RESUMO

Background: The novel Severe Acute Respiratory Syndrome Coronavirus-2 has led to a global pandemic in which case fatality rate (CFR) has varied from country to country. This study aims to identify factors that may explain the variation in CFR across countries. Methods: We identified 24 potential risk factors affecting CFR. For all countries with over 5000 reported COVID-19 cases, we used country-specific datasets from the WHO, the OECD, and the United Nations to quantify each of these factors. We examined univariable relationships of each variable with CFR, as well as correlations among predictors and potential interaction terms. Our final multivariable negative binomial model included univariable predictors of significance and all significant interaction terms. Results: Across the 39 countries under consideration, our model shows COVID-19 case fatality rate was best predicted by time to implementation of social distancing measures, hospital beds per 1000 individuals, percent population over 70 years, CT scanners per 1 million individuals, and (in countries with high population density) smoking prevalence. Conclusion: Our model predicted an increased CFR for countries that waited over 14 days to implement social distancing interventions after the 100th reported case. Smoking prevalence and percentage population over the age of 70 years were also associated with higher CFR. Hospital beds per 1000 and CT scanners per million were identified as possible protective factors associated with decreased CFR.


Assuntos
Infecções por Coronavirus/mortalidade , Modelos Estatísticos , Pneumonia Viral/mortalidade , Distribuição por Idade , Betacoronavirus , Controle de Doenças Transmissíveis/tendências , Número de Leitos em Hospital , Humanos , Internacionalidade , Pandemias , Fumar , Tomógrafos Computadorizados/provisão & distribução
6.
Eur Radiol Exp ; 4(1): 55, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-33000373

RESUMO

We investigated whether the internal gantry components of our computed tomography (CT) scanner contain severe acute respiratory syndrome 2 (SARS-CoV-2) ribonucleic acid (RNA), bacterial or fungal agents. From 1 to 27 March 2020, we performed 180 examinations of patients with confirmed SARS-CoV-2 infection using a dedicated CT scanner. On 27 March 2020, this CT gantry was opened and sampled in each of the following components: (a) gantry case; (b) inward airflow filter; (c) gantry motor; (d) x-ray tube; (e) outflow fan; (f) fan grid; (g) detectors; and (h) x-ray tube filter. To detect SARS-CoV-2 RNA, samples were analysed using reverse transcriptase-polymerase chain reaction (RT-PCR). To detect bacterial or fungal agents, samples have been collected using "replicate organism detection and counting" contact plates of 24 cm2, containing tryptic soy agar, and subsequently cultured. RT-PCR detected SARS-CoV-2 RNA in the inward airflow filter sample. RT-PCR of remaining gantry samples did not reveal the presence of SARS-CoV-2 RNA. Neither bacterial nor fungal agents grew in the agar-based growth medium after the incubation period. Our data showed that SARS-Cov-2 RNA can be found inside the CT gantry only in the inward airflow filter. All remaining CT gantry components were devoid of SARS-CoV-2 RNA.


Assuntos
Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/virologia , Contaminação de Equipamentos , Pneumonia Viral/virologia , Tomógrafos Computadorizados/virologia , Tomografia Computadorizada por Raios X/instrumentação , Humanos , Pandemias , RNA Viral/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real
7.
Medicine (Baltimore) ; 99(43): e22934, 2020 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-33120850

RESUMO

INDUCTION: Liver transplantation (LT) is the only final therapy for patients with acute liver failure (ALF) that cannot be controlled by conservative treatment. Acute pancreatitis (AP) is a recognized complication of ALF. The pathogenesis of AP in ALF patients has not yet been elucidated. The appearance of AP complicates the patients condition and causes a significantly increased risk of mortality. PATIENT CONCERNS: We report 2 fatal cases who were both admitted with yellowing of skin and sclera with general weakness lasting for 2 weeks. DIAGNOSIS: After admission, the laboratory examination of case 1 showed liver dysfunction with serum levels of total bilirubin (TB) 270 µmol/l, alanine aminotransferase (ALT) 106 U/l. Abdominal computed tomography (CT) showed pelvic and peritoneal cavity fluids, occupation of left lateral lobe of liver and unclear margin of pancreas. The clinical laboratory findings of case 2 revealed TB 351.1 µmol/l, ALT 252 U/l, blood lactic acid 18 mmol/l, ammonia 209 µmol/l. And abdominal CT showed pancreatic exudation. They were both diagnosed with acute liver failure, hepatic encephalopathy and AP which was confirmed during the operation. INTERVENTIONS: They were both received a routine orthotopic LT. OUTCOMES: After the surgery, their liver functions recovered well, and they received conventional conservative treatment for pancreatitis. However, the treatment was not adequately effective, and the infection was too serious and both died of multiple organ failure despite emergency rescue efforts on day 21 and day 19 after LT. CONCLUSION: AP is a serious complication that can contribute to prohibitive morbidity and mortality in LT patients. For this reason, the vulnerable state of the pancreas and the scoring system must be defined to help clinicians decide whether a patient is suitable for liver transplantation, and the clinical experience in the treatment of pancreatitis after LT needs to be summarized as an optimal treatment guideline to facilitate better treatment.


Assuntos
Falência Hepática Aguda/etiologia , Falência Hepática Aguda/terapia , Transplante de Fígado/mortalidade , Pancreatite/complicações , Idoso , Alanina Transaminase/sangue , Bilirrubina/sangue , Tratamento Conservador/métodos , Evolução Fatal , Encefalopatia Hepática/diagnóstico , Humanos , Período Intraoperatório , Masculino , Pessoa de Meia-Idade , Pancreatite/diagnóstico , Pancreatite/terapia , Prognóstico , Tomógrafos Computadorizados
8.
Artigo em Japonês | MEDLINE | ID: mdl-32814734

RESUMO

PURPOSE: This phantom study aimed to determine the optimal acquisition window size for phase-based respiratory gating in silicon photomultiplier (SiPM)-based fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and its acquisition time in respiratory-gated imaging with the optimal window size. METHODS: Images of a moving NEMA IEC Body Phantom SetTM with hot spheres were acquired. First, the tumor volume and the maximum standardized uptake value (SUVmax) of images reconstructed using a different window size were evaluated to define the optimal window size. Second, the quality of the images reconstructed using the optimal window size and different acquisition times was evaluated using the detectability score of the 10-mm hot sphere and physical indices. RESULTS: The volume and the SUVmax of the 10-mm hot sphere were improved when the window size was narrow, and there were no significant differences among images reconstructed using a window size narrower than 20%. To reconstruct an image using the 20% window size, an acquisition time of 5 min was required to visualize the 10-mm hot sphere. CONCLUSIONS: The optimal window size for phase-based respiratory gating is 20%. Further, an acquisition time of 5 min should be taken for respiratory-gated imaging with the 20% window size on SiPM-based FDG-PET/CT.


Assuntos
Fluordesoxiglucose F18 , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons , Imagens de Fantasmas , Tomografia por Emissão de Pósitrons , Tomógrafos Computadorizados
9.
Artigo em Japonês | MEDLINE | ID: mdl-32814735

RESUMO

PURPOSE: To compare the radiation dose and image quality using the conventional method for performing the front and side scout view and a new method for performing the side scout view, and then correct the table height at the scan isocenter and perform the front scout view. METHODS: We retrospectively analyzed fifty-six children who had underwent computed tomography (CT) examination between June 2014 and August 2018. We divided them into two groups. The conventional method was performed in 3 steps: 1. obtain the front scout view, 2. obtain the side scout view, and 3. main scan. Without table position correction, the new method was performed in 4 steps: 1. obtain the side scout view with table position correction, 2. patient correction at the scan isocenter, 3. obtain the front scout view, and 4. main scan. We used a 64-row CT scanner (LightSpeed VCT; GE Healthcare). Scan parameters were tube voltage 80 kV, automatic tube current modulation, noise index 16, slice thickness 5 mm, rotation time 0.4 s/rot, helical pitch 1.375, and reconstruction kernel standard. We recorded the volume dose index (CTDIvol) and dose length product (DLP) on the CT console and compared the radiation dose in both groups. To evaluate the image quality in both groups, the mean standard deviation of CT number (SD value) was measured within an approximately 5-10 mm2  circular region of interest. We measured the scan length of the pediatric patient and accuracy of pediatric positioning at the CT examination. A grid was displayed on the CT axial image, taken to evaluate the error from the scan isocenter during alignment, and the error between the height of half the body thickness and the scan isocenter was recorded. RESULTS: Scan lengths were median (minimum-maximum) values of 16.2 cm (10.8-21.5 cm) and 16.8 cm (11.5-23.0 cm). There were no significant differences in the scan length between both groups (p=0.47). In the group with table position correction, median (minimum-maximum) values for CTDIvol, DLP and SD value were 0.40 mGy (0.3-0.7 mGy), 7.6 mGyï½¥cm (4.4-11.5 mGyï½¥cm), and 24.0 HU (18.3-37.5 HU), respectively. In the group without the table position correction, median (minimum-maximum) values for CTDIvol, DLP and SD value were 0.40 mGy (0.3-0.6 mGy), 7.1 mGyï½¥cm (4.2-13.8 mGyï½¥cm), and 20.3 HU (11.3-28.8 HU), respectively. There were no significant differences in the CTDIvol and DLP values between both groups (p=0.42 and p=0.44, respectively); however, there were significant differences in the SD value in both groups (p<0.01). The error for the accuracy of pediatric positioning was 0 mm (0 to 0 mm) and 10 mm (-16 to+59 mm) using the conventional and new methods (p<0.01), respectively. CONCLUSIONS: It was suggested that the optimum image could be obtained during CT scan with automatic tube current modulation by using this potential new method (1. obtain the side scout view, 2. patient correction at the scan isocenter, 3. obtain the side scout view, and 4. main scan).


Assuntos
Ruído , Tomografia Computadorizada por Raios X , Criança , Humanos , Doses de Radiação , Estudos Retrospectivos , Tomógrafos Computadorizados
10.
Zhonghua Er Ke Za Zhi ; 58(8): 674-678, 2020 Aug 02.
Artigo em Chinês | MEDLINE | ID: mdl-32842389

RESUMO

Objective: To analyze the clinical features of 2 children with hereditary hemorrhagic telangiectasia (HHT) and review relevant literature. Methods: The clinical data of 2 children with HHT who were admitted to Beijing Children's Hospital, Capital Medical University from February 2017 to June 2018 were retrospectively analyzed. Meanwhile, the relevant papers published before December 2019 in Wanfang and Pubmed database were searched with the key words of "hereditary hemorrhagic telangiectasia" in Chinese and English, and reviewed. Results: The first case was an 11-year-old boy, presented with fever and cough for 6 days. His past history revealed 3 times of left pneumonia and mild epistaxis. Ultrasound of the chest soft tissue found hemangioma and vascular malformation. Enhanced CT with vascular reconstruction suggested pulmonary arteriovenous malformation and multiple arteriovenous fistulas in the liver. After being treated with interventional pulmonary arteriovenous fistula embolization, his condition improved. The second case was a 12-year-old girl, presented with iron deficiency anemia during the past 3 years. Endoscopic resection of polyps had been performed before due to multiple polyps in the colon. High-resolution lung CT revealed multiple ground-glass nodules in bilateral lungs. Ultrasound of the digestive tract suggested small intestine polyps and secondary chronic loose intussusception. After admission, small bowel intussusception reduction was performed, and the polyps were ligated. Her whole exon gene testing suggested SMAD4 heterozygous variation. In the large number of reported cases, HHT1 and HHT2 are the main type. Conclusions: Children with HHT may present with anemia and repeated intestinal polyps. It is worth noting that visceral arteriovenous malformations, such as pulmonary arteriovenous malformations, which is easily misdiagnosed as recurrent pneumonia, can also occur in children with HHT. Enhanced CT with vascular reconstruction can help find pulmonary arteriovenous malformation, and timely genetic test can confirm the diagnosis.


Assuntos
Fístula Arteriovenosa/complicações , Malformações Arteriovenosas/diagnóstico , Telangiectasia Hemorrágica Hereditária/complicações , Telangiectasia Hemorrágica Hereditária/diagnóstico , Fístula Arteriovenosa/cirurgia , Malformações Arteriovenosas/diagnóstico por imagem , Malformações Arteriovenosas/etiologia , Criança , Tosse/etiologia , Feminino , Febre/etiologia , Humanos , Fígado/diagnóstico por imagem , Masculino , Veias Pulmonares/anormalidades , Veias Pulmonares/diagnóstico por imagem , Estudos Retrospectivos , Telangiectasia Hemorrágica Hereditária/genética , Tomógrafos Computadorizados
14.
Dis Colon Rectum ; 63(6): 723-726, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32384402

RESUMO

CASE SUMMARY: A 28-year-old nulliparous woman presented with rectal bleeding. Colonoscopy revealed a 4-cm malignant-appearing mass in the proximal rectum, and biopsies confirmed invasive adenocarcinoma of the rectum. Computed tomography scan showed no evidence of metastatic disease. Staging MRI found transmural extension with minimal stranding in the adjacent fat, as well as no evidence of pathological pelvic adenopathy, consistent with a T3N0 lesion. The proposed treatment plan involved neoadjuvant chemotherapy and radiation therapy before primary surgical resection. The patient desired fertility preservation and was referred immediately to Reproductive Endocrinology and Infertility. She underwent assisted reproduction with oocyte and blastocyst cryopreservation followed by laparoscopic ovarian transposition. Nine months after surgical low anterior resection of the tumor and completion of her cancer treatment, her ovaries were repositioned to their normal pelvic position during an ileostomy takedown procedure. She underwent a frozen embryo transfer but did not conceive. She resumed menses and later conceived spontaneously. Her pregnancy was complicated by cervical incompetence, requiring cervical cerclage. She delivered a live male infant via cesarean delivery at 32 weeks gestation, approximately 2 years after completion of cancer therapy. Four years after diagnosis, the patient remains in remission with undetectable CEA levels.


Assuntos
Neoplasias Colorretais/patologia , Preservação da Fertilidade/métodos , Hemorragia Gastrointestinal/etiologia , Reto/patologia , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/radioterapia , Adulto , Cesárea/métodos , Colonoscopia/métodos , Neoplasias Colorretais/diagnóstico por imagem , Criopreservação/métodos , Feminino , Humanos , Recém-Nascido , Imagem por Ressonância Magnética/métodos , Masculino , Terapia Neoadjuvante , Estadiamento de Neoplasias/métodos , Ovário/cirurgia , Gravidez , Tomógrafos Computadorizados
15.
Artigo em Japonês | MEDLINE | ID: mdl-32307362

RESUMO

Presently, the scanning start angle of the X-ray tube of X-ray computed tomography (CT) scanners cannot be controlled. As a result, there is room for reducing patient dose because the peaks of the dose distributions may overlap during multiphasic CT imaging. This study investigated methods of dose reduction by performing a Monte Carlo simulation of the X-ray tube scanning start angle and locally absorbed dose in multiphasic CT imaging. In the Monte Carlo simulation, the largest decrease in the absorbed dose was seen, when the scanning start angle between the phases was±180°. Even though with present X-ray CT scanners, the scanning start angle cannot be controlled, it is possible to decrease the absorbed dose by taking the orbital synchronized scanning and scanning range into consideration. In future we hope that, we will be able to easily reduce the dose by controlling the scanning start angle.


Assuntos
Radiometria , Tomografia Computadorizada por Raios X , Humanos , Método de Monte Carlo , Imagens de Fantasmas , Doses de Radiação , Tomógrafos Computadorizados
19.
Eur J Radiol ; 125: 108863, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32062330

RESUMO

PURPOSE: To define National Diagnostic Reference Levels (NDRLs) for computed tomography (CT) for Austria on adult patients. METHOD: In the course of a nationwide survey on common CT-examinations between June 2018 and November 2018, datasets were requested from all Austrian hospitals and radiology centers with CT-scanners. All facilities were asked to report a minimum sample of 10 representative dose length product (DLP) values per examination type and CT-scanner, including information about scan sequences, iterative reconstruction (IR) algorithms and, if available, patient data. Examination types included into the survey were the most common CT-indications for the anatomic regions head, facial bones, thorax, abdomen and pelvis. 3rd quartiles of CT-scanner median DLPs were calculated and compared to Austrian and international NDRLs. RESULTS: For 76 % of all operating CT-scanners, DLP data was submitted varying from 13 to 172 scanners per examination type. Mean year of manufacture of the CT-scanners was 2011, ranging from 2003 to 2018. In 66 % of the examinations, IR was used. 3rd quartile is on average 21 % lower for scanners using IR algorithms as opposed to scanners or protocols not using IR. In the case of gender differences, the DLP for females is on average 17 % lower than for males. CONCLUSIONS: The new recommendations for CT NDRLs for Austria based on a nationwide survey are on average 13 % lower than the current Austrian NDRLs and correspond well to recent German and Swiss NDRLs. 3rd quartiles for DLP are dependent on gender, the use of IR and year of manufacture of the CT-scanners.


Assuntos
Interpretação de Imagem Assistida por Computador/métodos , Doses de Radiação , Inquéritos e Questionários/estatística & dados numéricos , Tomografia Computadorizada por Raios X/métodos , Tomografia Computadorizada por Raios X/normas , Adulto , Áustria , Feminino , Humanos , Interpretação de Imagem Assistida por Computador/estatística & dados numéricos , Masculino , Valores de Referência , Fatores Sexuais , Tomógrafos Computadorizados/estatística & dados numéricos , Tomografia Computadorizada por Raios X/estatística & dados numéricos
20.
Eur Radiol ; 30(5): 2712-2721, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32025830

RESUMO

OBJECTIVES: To compare the scan acquisition time, radiation dose, subjective and objective image quality of two dual-source CT scanners (DSCT) for detection of acute pulmonary embolism. METHODS: Two hundred twenty-one scans performed on the 2nd-generation DSCT and 354 scans on the 3rd-generation DSCT were included in this large retrospective study. In a randomized blinded design, two radiologists independently reviewed the scans using a 5-point Likert scale. Radiation dose and objective image quality parameters were calculated. RESULTS: Mean acquisition time was significantly lower in the 3rd-generation DSCT (2.81 s ± 0.1 in comparison with 9.7 s ± 0.15 [mean ± SD] respectively; p < 0.0001) with the 3rd generation 3.4 times faster. The mean subjective image quality score was 4.33/5 and 4/5 for the 3rd- and 2nd-generation DSCT respectively (p < 0.0001) with strong interobserver reliability agreement. DLP, CTDIvol, and ED were significantly lower in the 3rd than the 2nd generation (175.6 ± 63.7 mGy cm; 5.3 ± 1.9 mGy and 2.8 ± 1.2 mSv in comparison with 266 ± 255 mGy.cm; 7.8 ± 2.2 mGy and 3.8 ± 4.3 mSv). Noise was significantly lower in the 3rd generation (p < 0.01). Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and figure of merit (FOM), a dose-insensitive index for CNR, were significantly higher in the 3rd-generation DSCT (33.5 ± 23.4; 29.0 ± 21.3 and 543.7 ± 1037 in comparison with 23.4 ± 17.7; 19.4 ± 16.0 and 170.5 ± 284.3). CONCLUSION: Objective and subjective image quality are significantly higher on the 3rd-generation DSCT with significantly lower mean acquisition time and radiation dose. KEY POINTS: • The 3rd-generation DSCT scanner provides an improved image quality, less perceived artifacts, and lower radiation dose in comparison with the 2nd-generation DSCT, when operating in dual-energy (DE) mode. • The 3.4-times-faster 3rd-generation DSCT scanner can be of particular value in patients with chronic lung diseases or breathing difficulties that prevent adequate breathhold.


Assuntos
Angiografia por Tomografia Computadorizada/instrumentação , Embolia Pulmonar/diagnóstico por imagem , Doses de Radiação , Tomógrafos Computadorizados , Adulto , Idoso , Artefatos , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estudos Retrospectivos , Razão Sinal-Ruído , Fatores de Tempo , Tomografia Computadorizada por Raios X/métodos
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