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1.
Nat Commun ; 12(1): 1832, 2021 03 23.
Artículo en Inglés | MEDLINE | ID: mdl-33758201

RESUMEN

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.


Asunto(s)
Senescencia Celular/efectos de los fármacos , Células Endoteliales/metabolismo , Glucocorticoides/farmacología , Neovascularización Fisiológica/efectos de los fármacos , Proteínas del Tejido Nervioso/metabolismo , Osteoclastos/metabolismo , Ribonucleasa Pancreática/metabolismo , Animales , Apoptosis/efectos de los fármacos , Desarrollo Óseo/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Senescencia Celular/genética , Células Endoteliales/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana , Humanos , Inmunohistoquímica , Hibridación Fluorescente in Situ , Metilprednisolona/farmacología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Neovascularización Patológica , Proteínas del Tejido Nervioso/genética , Osteoclastos/efectos de los fármacos , Osteoclastos/enzimología , Osteogénesis/efectos de los fármacos , ARN Ribosómico/biosíntesis , ARN Interferente Pequeño , Proteínas Recombinantes , Ribonucleasa Pancreática/genética , Ribonucleasa Pancreática/farmacología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Tomógrafos Computarizados por Rayos X
2.
J Laryngol Otol ; 135(2): 125-129, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33568241

RESUMEN

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.


Asunto(s)
Pérdida de Líquido Cefalorraquídeo/epidemiología , Implantación Coclear/métodos , Oído Interno/anomalías , Pérdida Auditiva Sensorineural/cirugía , Complicaciones Intraoperatorias/epidemiología , Adulto , Estudios de Casos y Controles , Niño , Implantes Cocleares/efectos adversos , Oído Interno/diagnóstico por imagen , Oído Interno/patología , Oído Interno/cirugía , Pérdida Auditiva Sensorineural/rehabilitación , Humanos , India/epidemiología , Complicaciones Intraoperatorias/patología , Masculino , Estudios Retrospectivos , Percepción del Habla/fisiología , Tomógrafos Computarizados por Rayos X
4.
Artículo en Inglés | MEDLINE | ID: mdl-33167564

RESUMEN

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.


Asunto(s)
Infecciones por Coronavirus/mortalidad , Modelos Estadísticos , Neumonía Viral/mortalidad , Distribución por Edad , Betacoronavirus , Control de Enfermedades Transmisibles/tendencias , Capacidad de Camas en Hospitales , Humanos , Internacionalidad , Pandemias , Fumar , Tomógrafos Computarizados por Rayos X/provisión & distribución
5.
Eur Radiol Exp ; 4(1): 55, 2020 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-33000373

RESUMEN

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.


Asunto(s)
Betacoronavirus/aislamiento & purificación , Infecciones por Coronavirus/virología , Contaminación de Equipos , Neumonía Viral/virología , Tomógrafos Computarizados por Rayos X/virología , Tomografía Computarizada por Rayos X/instrumentación , Humanos , Pandemias , ARN Viral/aislamiento & purificación , Reacción en Cadena en Tiempo Real de la Polimerasa
6.
Medicine (Baltimore) ; 99(43): e22934, 2020 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-33120850

RESUMEN

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.


Asunto(s)
Fallo Hepático Agudo/etiología , Fallo Hepático Agudo/terapia , Trasplante de Hígado/mortalidad , Pancreatitis/complicaciones , Anciano , Alanina Transaminasa/sangre , Bilirrubina/sangre , Tratamiento Conservador/métodos , Resultado Fatal , Encefalopatía Hepática/diagnóstico , Humanos , Periodo Intraoperatorio , Masculino , Persona de Mediana Edad , Pancreatitis/diagnóstico , Pancreatitis/terapia , Pronóstico , Tomógrafos Computarizados por Rayos X
7.
Artículo en Japonés | MEDLINE | ID: mdl-32814734

RESUMEN

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.


Asunto(s)
Fluorodesoxiglucosa F18 , Tomografía Computarizada por Tomografía de Emisión de Positrones , Fantasmas de Imagen , Tomografía de Emisión de Positrones , Tomógrafos Computarizados por Rayos X
8.
Artículo en Japonés | MEDLINE | ID: mdl-32814735

RESUMEN

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).


Asunto(s)
Ruido , Tomografía Computarizada por Rayos X , Niño , Humanos , Dosis de Radiación , Estudios Retrospectivos , Tomógrafos Computarizados por Rayos X
9.
Zhonghua Er Ke Za Zhi ; 58(8): 674-678, 2020 Aug 02.
Artículo en Chino | MEDLINE | ID: mdl-32842389

RESUMEN

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.


Asunto(s)
Fístula Arteriovenosa/complicaciones , Malformaciones Arteriovenosas/diagnóstico , Telangiectasia Hemorrágica Hereditaria/complicaciones , Telangiectasia Hemorrágica Hereditaria/diagnóstico , Fístula Arteriovenosa/cirugía , Malformaciones Arteriovenosas/diagnóstico por imagen , Malformaciones Arteriovenosas/etiología , Niño , Tos/etiología , Femenino , Fiebre/etiología , Humanos , Hígado/diagnóstico por imagen , Masculino , Venas Pulmonares/anomalías , Venas Pulmonares/diagnóstico por imagen , Estudios Retrospectivos , Telangiectasia Hemorrágica Hereditaria/genética , Tomógrafos Computarizados por Rayos X
13.
Dis Colon Rectum ; 63(6): 723-726, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32384402

RESUMEN

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.


Asunto(s)
Neoplasias Colorrectales/patología , Preservación de la Fertilidad/métodos , Hemorragia Gastrointestinal/etiología , Recto/patología , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/radioterapia , Adulto , Cesárea/métodos , Colonoscopía/métodos , Neoplasias Colorrectales/diagnóstico por imagen , Criopreservación/métodos , Femenino , Humanos , Recién Nacido , Imagen por Resonancia Magnética/métodos , Masculino , Terapia Neoadyuvante , Estadificación de Neoplasias/métodos , Ovario/cirugía , Embarazo , Tomógrafos Computarizados por Rayos X
14.
Artículo en Japonés | MEDLINE | ID: mdl-32307362

RESUMEN

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.


Asunto(s)
Radiometría , Tomografía Computarizada por Rayos X , Humanos , Método de Montecarlo , Fantasmas de Imagen , Dosis de Radiación , Tomógrafos Computarizados por Rayos X
18.
Eur J Radiol ; 125: 108863, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32062330

RESUMEN

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.


Asunto(s)
Interpretación de Imagen Asistida por Computador/métodos , Dosis de Radiación , Encuestas y Cuestionarios/estadística & datos numéricos , Tomografía Computarizada por Rayos X/métodos , Tomografía Computarizada por Rayos X/normas , Adulto , Austria , Femenino , Humanos , Interpretación de Imagen Asistida por Computador/estadística & datos numéricos , Masculino , Valores de Referencia , Factores Sexuales , Tomógrafos Computarizados por Rayos X/estadística & datos numéricos , Tomografía Computarizada por Rayos X/estadística & datos numéricos
19.
Eur Radiol ; 30(5): 2712-2721, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32025830

RESUMEN

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.


Asunto(s)
Angiografía por Tomografía Computarizada/instrumentación , Embolia Pulmonar/diagnóstico por imagen , Dosis de Radiación , Tomógrafos Computarizados por Rayos X , Adulto , Anciano , Artefactos , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Estudios Retrospectivos , Relación Señal-Ruido , Factores de Tiempo , Tomografía Computarizada por Rayos X/métodos
20.
Eur Radiol ; 30(5): 2552-2560, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32040726

RESUMEN

OBJECTIVES: To evaluate the technical performance of an ultra-high-resolution CT (UHRCT) system. METHODS: The physico-technical capabilities of a novel commercial UHRCT system were assessed and compared with those of a current-generation multi-detector (MDCT) system. The super-high-resolution (SHR) mode of the system uses 0.25 mm (at isocentre) detector elements (dels) in the in-plane and longitudinal directions, while the high-resolution (HR) mode bins two dels in the longitudinal direction. The normal-resolution (NR) mode bins dels 2 × 2, resulting in a del-size equivalent to that of the MDCT system. In general, standard procedures and phantoms were used to perform these assessments. RESULTS: The UHRCT MTF (10% MTF 4.1 lp/mm) is twice as high as that of the MDCT (10% MTF 1.9 lp/mm), which is comparable to the MTF in the NR mode (10% MTF 1.7 lp/mm). The width of the slice sensitivity profile in the SHR mode (FWHM 0.45 mm) is about 60% of that of the MDCT (FWHM 0.77 mm). Uniformity and CT numbers are within the expected range. Noise in the high-resolution modes has a higher magnitude and higher frequency components compared with MDCT. Low-contrast visibility is lower for the NR, HR and SHR modes compared with MDCT, but about a 14%, for NR, and 23%, for HR and SHR, dose increase gives the same results. CONCLUSIONS: HR and SHR mode scanning results in double the spatial resolution, with about a 23% increase in dose required to achieve the same low-contrast detectability. KEY POINTS: • Resolution on UHRCT is up to twice as high as for the tested MDCT. • With abdominal settings, UHRCT needs higher dose for the same low-contrast detectability as MDCT, but dose is still below achievable levels as defined by current diagnostic reference levels. • The UHRCT system used in normal-resolution mode yields comparable resolution and noise characteristics as the MDCT system.


Asunto(s)
Tomógrafos Computarizados por Rayos X , Tomografía Computarizada por Rayos X/métodos , Diseño de Equipo , Humanos , Fantasmas de Imagen , Reproducibilidad de los Resultados
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