Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 7.472
Filtrar
1.
J Comput Assist Tomogr ; 44(1): 13-19, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939876

RESUMO

OBJECTIVE: To evaluate image quality and radiation dose exposure of low-kV setting and low-volume contrast medium (CM) computed tomography angiography (CTA) protocol for transcatheter aortic valve implantation (TAVI) planning in comparison with standard CTA protocol. METHODS: Sixty-patients were examined with 256-row MDCT for TAVI planning: 32 patients (study group) were evaluated using 80-kV electrocardiogram-gated protocol with 60 mL of CM and IMR reconstruction; 28 patients underwent a standard electrocardiogram-gated CTA study (100 kV; 80 mL of CM; iDose4 reconstruction). Subjective and objective image quality was evaluated in each patient at different aortic levels. Finally, we collected radiation dose exposure data (CT dose index and dose-length product) of both groups. RESULTS: In study protocol, significant higher mean attenuation values were achieved in all measurements compared with the standard protocol. There were no significant differences in the subjective image quality evaluation in both groups. Mean dose-length product of study group was 56% lower than in the control one (P < 0.0001). CONCLUSION: Low-kV and low-CM volume CTA, combined with IMR, allows to correctly performing TAVI planning with high-quality images and significant radiation dose reduction compared with standard CTA protocol.


Assuntos
Estenose da Valva Aórtica/diagnóstico por imagem , Angiografia por Tomografia Computadorizada/métodos , Meios de Contraste/administração & dosagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Estenose da Valva Aórtica/cirurgia , Feminino , Humanos , Bases de Conhecimento , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada Multidetectores , Período Pré-Operatório , Doses de Radiação , Substituição da Valva Aórtica Transcateter
2.
J Comput Assist Tomogr ; 44(1): 26-31, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939878

RESUMO

Coronary computed tomography angiography is widely used in clinical practice. Although 3-dimensional (D) volume rendering is useful for interpretation of coronary path and territory, 2D output is common for image interpretation. Most picture archiving and communication system is incapable of manipulating 3D due to insufficient graphic specification. Thus, 2D bull's eye map display is frequently used in cardiac imaging. We developed a bull's eye map which emulated the anatomical information of individual coronary path and dominancy.


Assuntos
Vasos Coronários/diagnóstico por imagem , Ventrículos do Coração/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Idoso , Algoritmos , Angiografia por Tomografia Computadorizada , Feminino , Humanos , Imagem Tridimensional , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
3.
J Comput Assist Tomogr ; 44(1): 37-42, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939880

RESUMO

OBJECTIVE: The purpose of this study was to determine whether computed tomography (CT) angiography with machine learning (ML) can be used to predict the rapid growth of abdominal aortic aneurysm (AAA). MATERIALS AND METHODS: This retrospective study was approved by our institutional review board. Fifty consecutive patients (45 men, 5 women, 73.5 years) with small AAA (38.5 ± 6.2 mm) had undergone CT angiography. To be included, patients required at least 2 CT scans a minimum of 6 months apart. Abdominal aortic aneurysm growth, estimated by change per year, was compared between patients with baseline infrarenal aortic minor axis. For each axial image, major axis of AAA, minor axis of AAA, major axis of lumen without intraluminal thrombi (ILT), minor axis of lumen without ILT, AAA area, lumen area without ILT, ILT area, maximum ILT area, and maximum ILT thickness were measured. We developed a prediction model using an ML method (to predict expansion >4 mm/y) and calculated the area under the receiver operating characteristic curve of this model via 10-fold cross-validation. RESULTS: The median aneurysm expansion was 3.0 mm/y. Major axis of AAA and AAA area correlated significantly with future AAA expansion (r = 0.472, 0.416 all P < 0.01). Machine learning and major axis of AAA were a strong predictor of significant AAA expansion (>4 mm/y) (area under the receiver operating characteristic curve were 0.86 and 0.78). CONCLUSIONS: Machine learning is an effective method for the prediction of expansion risk of AAA. Abdominal aortic aneurysm area and major axis of AAA are the important factors to reflect AAA expansion.


Assuntos
Aneurisma da Aorta Abdominal/diagnóstico por imagem , Angiografia por Tomografia Computadorizada/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Idoso , Idoso de 80 Anos ou mais , Progressão da Doença , Feminino , Humanos , Aprendizado de Máquina , Masculino , Estudos Retrospectivos
4.
J Comput Assist Tomogr ; 44(1): 53-58, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939882

RESUMO

OBJECTIVE: In the diagnosis of superior semicircular canal dehiscence (SSCD), computed tomography (CT) is the only imaging method. The aims of the study were to show that reformat images are more accurate than standard planes for diagnosis of SSCD and to determine the prevalence of SSCD. METHODS: The retrospective review yielded 1309 temporal CTs performed in our radiology department for any reason. Two radiologist interpreted CTs in standard planes collaboratively. Patients with SSCD were reinterpreted in Pöschl and Stenvers planes by 2 radiologists separately. RESULTS: Statistical analysis was made by accepting that 2 radiologists diagnosis were accurate in Pöschl plane. Coronal plane sensitivity 86%, specificity 64%, Stenvers plane sensitivity 96%, and specificity 52% have been found in the mean result of 2 observers (P < 0.001). CONCLUSIONS: In the diagnosis of SSCD, standard and Stenvers planes can cause false-negative and false-positive diagnoses. Interpretation in Pöschl plane can significantly increase sensitivity, specificity, negative, and positive predictive values for diagnosing dehiscence.


Assuntos
Doenças do Labirinto/diagnóstico por imagem , Tomografia Computadorizada Multidetectores/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Canais Semicirculares/anormalidades , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Canais Semicirculares/diagnóstico por imagem , Sensibilidade e Especificidade , Adulto Jovem
5.
J Comput Assist Tomogr ; 44(1): 83-89, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939887

RESUMO

RATIONALE AND OBJECTIVES: This novel study aims to investigate texture parameters in distinguishing malignant and benign breast lesions classified as Breast Imaging Reporting and Data System 4 in dynamic contrast-enhanced magnetic resonance imaging (MRI). MATERIALS AND METHODS: This retrospective study included 203 patients with 136 breast cancer and 67 benign lesions who underwent breast MRI between November 23, 2016, and August 27, 2018. Co-occurrence matrix-based texture features were extracted from each lesion on T1-weighted contrast-enhanced MRI using MatLab software. The association between texture parameters and breast lesions was analyzed, and the diagnostic model for breast cancer was created. Classification performance was evaluated by the area under the receiver operating characteristic curve, sensitivity, and specificity. RESULTS: Significant differences were seen between malignant and benign lesions for a number of textural features, including contrast, correlation, autocorrelation, dissimilarity, cluster shade, and cluster performance (P < 0.05). After the analysis of the multicollinearity, 5 texture features (contrast, correlation, dissimilarity, cluster shade, and cluster performance) were included for the next principal component analysis. The differentiation accuracy of breast cancer based on the diagnostic model was 0.948 (95% confidence interval, 0.908-0.974). CONCLUSIONS: Texture features that measure randomness, heterogeneity, or homogeneity may reflect underlying growth patterns of breast lesions and show great difference in malignant and benign lesions. Therefore, texture analysis may be a valuable assisted tool for diagnostic analysis on breast.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Área Sob a Curva , Feminino , Humanos , Imagem por Ressonância Magnética , Pessoa de Meia-Idade , Estudos Retrospectivos , Sensibilidade e Especificidade , Adulto Jovem
6.
J Comput Assist Tomogr ; 44(1): 95-101, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939889

RESUMO

PURPOSE: This study aimed to evaluate image quality of ultra-low dose chest computed tomography using 6 iterative reconstruction (IR) algorithms. METHOD: A lung phantom was scanned on 4 computed tomography scanners using fixed tube voltages and the lowest mAs available on each scanner, resulting in dose levels of 0.1 to 0.2 mGy (80 kVp) and 0.3 to 1 mGy (140 kVp) volume CT dose index (CTDIvol). Images were reconstructed with IR available on the scanners. Image noise, signal-to-noise ratios, contrast-to-noise ratios, uniformity, and noise power spectrum (NPS) were assessed for evaluation of image quality. RESULTS: Image quality parameters increased with increasing dose for all algorithms. At constant dose levels, model-based techniques improved the contrast-to-noise ratio of lesions more than the statistical algorithms. All algorithms tested at 0.1 mGy showed lower NPS peak frequencies compared with 0.39 mGy. In contrast to the statistical techniques, model-based algorithms showed lower NPS peak frequencies at the lowest doses, indicating a coarser and blotchier noise texture. CONCLUSION: This study shows the importance of evaluating IR when introduced clinically.


Assuntos
Pulmão/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/instrumentação , Algoritmos , Meios de Contraste , Humanos , Imagens de Fantasmas , Doses de Radiação , Razão Sinal-Ruído
7.
J Comput Assist Tomogr ; 44(1): 118-123, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939892

RESUMO

AIM: This study aimed to assess the interobserver agreement of magnetic resonance (MR) imaging of Liver Imaging Reporting and Data System version 2018 (LI-RADS v2018). SUBJECTS AND METHODS: Retrospective analysis was done for 119 consecutive patients (77 male and 42 female) at risk of hepatocellular carcinoma who underwent dynamic contrast MR imaging. Image analysis was done by 2 independent and blinded readers for arterial phase hyperenhancement, washout appearance, enhancing capsule appearance, and size. Hepatic lesions were classified into 7 groups according to LI-RADS v2018. RESULTS: There was excellent interobserver agreement of both reviewers for LR version 4 (κ = 0.887, P = 0.001) with 90.76% agreement. There was excellent interobserver agreement for nonrim arterial phase hyperenhancement (κ = 0.948; 95% confidence interval [CI], 0.89-0.99; P = 0.001), washout appearance (κ = 0.949; 95% CI, 0.89-1.0; P = 0.001); and enhancing capsule (κ = 0.848; 95% CI, 0.73-0.97; P = 0.001) and excellent reliability of size (interclass correlation, 0.99; P = 0.001). There was excellent interobserver agreement for LR-1 (κ = 1.00, P = 0.001), LR-2 (κ = 0.94, P = 0.001), LR-5 (κ = 0.839, P = 0.001), LR-M (κ = 1.00, P = 0.001), and LR-TIV (κ = 1.00; 95% CI, 1.0-1.0; P = 0.001), and good agreement for LR-3 (κ = 0.61, P = 0.001) and LR-4 (κ = 0.61, P = 0.001). CONCLUSION: MR imaging of LI-RADS v2018 is a reliable imaging modality and reporting system that may be used for standard interpretation of hepatic focal lesions.


Assuntos
Carcinoma Hepatocelular/diagnóstico por imagem , Neoplasias Hepáticas/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Estudos Retrospectivos
8.
J Comput Assist Tomogr ; 44(1): 138-144, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939895

RESUMO

OBJECTIVE: The aim of this study was to determine the influence of virtual monoenergetic images (vMEIs) on renal cortex volumetry (RCV) and estimation of split-renal function. METHODS: Twenty-five patients (mean ± SD, 64.7 ± 9.9 years) underwent a contrast-enhanced dual-layer spectral detector computed tomography. Images were reconstructed with a reference standard (iterative model reconstruction, IMRRef), a newly spectral detector computed tomography algorithm (SPcon) and vMEI at 40, 60, 80, 100, and 120 keV. Two blinded independent readers performed RCV on all data sets with a semiautomated tool. RESULTS: Total kidney volume was up to 15% higher in vMEI at 40/60 keV compared with IMRRef (P < 0.001). Total kidney volume with vMEI at 80/100 keV was similar to IMRRef (P < 0.001). Split-renal function was similar in all reconstructions at approximately 50% ± 3%. Bland-Altman analysis showed no significant differences (P > 0.05), except for 40 keV versus SPcon (P < 0.05). The time required to perform RCV was reasonable, approximately 4 minutes, and showed no significant differences among reconstructions. Interreader agreement was greatest with vMEI at 80 keV (r = 0.68; 95% confidence interval, 0.39-0.85; P < 0.0002) followed by IMRRef images (r = 0.67; 95% confidence interval, 0.37-0.84; P < 0.0003). IMRRef showed the highest mean Hounsfield unit for cortex/medulla of 223.4 ± 73.7/62.5 ± 19.7 and a ratio of 3.7. CONCLUSIONS: Semiautomated RCV performed with vMEI and IMRRef/SPcon is feasible and showed no clinically relevant differences with regard to split-renal function. Low-kiloelectron volt vMEI showed greater tissue contrast and total kidney volume but no benefit for RCV. Moderate-kiloelectron volt vMEI (80 keV) results were similar to IMRRef with a faster postprocessing time.


Assuntos
Córtex Renal/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Imagem Radiográfica a Partir de Emissão de Duplo Fóton/métodos , Tomografia Computadorizada por Raios X/métodos , Idoso , Algoritmos , Feminino , Humanos , Córtex Renal/patologia , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Estudos Retrospectivos , Sensibilidade e Especificidade , Razão Sinal-Ruído
9.
J Comput Assist Tomogr ; 44(1): 145-152, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939896

RESUMO

OBJECTIVES: We investigated the computed tomographic characteristics of gastrointestinal air motion artifact (GIAMA), which can be misinterpreted as active gastrointestinal bleeding. METHODS: We simulated GIAMA using 3 types of air-ball phantoms (air-ball in water, air-ball in oil, air-water-ball in oil) and a bovine intestine in oil phantom. We also performed a retrospective clinical review of precontrast abdominal computed tomography images of 76 patients to investigate the frequency, location, shape, and maximum density of hyperdense GIAMA. RESULTS: In phantom studies, air motion artifacts appeared as dark and bright streak artifacts at the borders of a moving air-ball and water or oil. In the clinical study, hyperdense GIAMA was visualized in 60 (79.0%) of 76 patients. The small intestine was most commonly affected (46.4%), and the intramural type had the highest frequency (58.0%). CONCLUSION: Knowing the radiologic features of GIAMA can assists radiologists in identifying active gastrointestinal bleeding sites accurately.


Assuntos
Hemorragia Gastrointestinal/diagnóstico por imagem , Tomografia Computadorizada Multidetectores/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Bovinos , Reações Falso-Positivas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Imagens de Fantasmas , Estudos Retrospectivos , Sensibilidade e Especificidade , Adulto Jovem
10.
J Comput Assist Tomogr ; 44(1): 43-46, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31789683

RESUMO

OBJECTIVE: The objective of this study was to investigate the frequency of hippocampal sulcus remnants (HSRs) in nonelderly adults using ultra-high-resolution 7T magnetic resonance (MR) images and their imaging features. METHODS: A total of 33 healthy adults underwent 7T MR, and multiplanar images of 66 temporal lobes were reviewed independently by 2 neuroradiologists. The detectability of the HSR was calculated. In addition, the interobserver agreement on the rating scale was evaluated using the κ statistic. RESULTS: Both observers identified HSRs with 7T MR images in all subjects. Excellent interobserver agreement was shown (κ = 1.0). The shape of HSRs was variable (spot-like, curvilinear, ovoid, or beaded appearance). Volumes of the HSRs were not correlated with age. CONCLUSIONS: Hippocampal sulcus remnants are commonly seen in healthy nonelderly adults using 7T MR imaging. Accurate diagnosis of HSR based on the microanatomy of hippocampus makes it easier to differentiate them from lesions, and it may help prevent unnecessary treatment.


Assuntos
Hipocampo/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Adulto , Algoritmos , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Adulto Jovem
11.
J Comput Assist Tomogr ; 44(1): 75-77, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31804241

RESUMO

Computed tomography perfusion (CTP) is increasingly used to determine treatment eligibility for acute ischemic stroke patients. Automated postprocessing of raw CTP data is routinely used, but it can fail. In reviewing 176 consecutive acute ischemic stroke patients, failures occurred in 20 patients (11%) during automated postprocessing by the RAPID software. Failures were caused by motion (n = 11, 73%), streak artifacts (n = 2, 13%), and poor contrast bolus arrival (n = 2, 13%). Stroke physicians should review CTP results with care before they are being integrated in their decision-making process.


Assuntos
Isquemia Encefálica/diagnóstico por imagem , Processamento Eletrônico de Dados/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Acidente Vascular Cerebral/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Imagem de Perfusão/métodos , Fatores de Risco , Sensibilidade e Especificidade , Software , Tomografia Computadorizada por Raios X
12.
Br J Radiol ; 93(1105): 20190069, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31642702

RESUMO

OBJECTIVE: To evaluate the impact of different metal artifact reduction (MAR) algorithms on Hounsfield unit (HU) and standardized uptake values (SUV) in a phantom setting and verify these results in patients with metallic implants undergoing oncological PET/CT examinations. METHODS AND MATERIALS: In this prospective study, PET-CT examinations of 28 oncological patients (14 female, 14 male, mean age 69.5 ± 15.2y) with 38 different metal implants were included. CT datasets were reconstructed using standard weighted filtered back projection (WFBP) without MAR, MAR in image space (MARIS) and iterative MAR (iMAR, hip algorithm). The three datasets were used for PET attenuation correction. SUV and HU measurements were performed at the site of the most prominent bright and dark band artifacts. Differences between HU and SUV values across the different reconstructions were compared using paired t-tests. Bonferroni correction was used to prevent alpha-error accumulation (p < 0.017). RESULTS: For bright band artifacts, MARIS led to a non-significant mean decrease of 12.0% (345 ± 315 HU) in comparison with WFBP (391 ± 293 HU), whereas iMAR led to a significant decrease of 68.3% (125 ± 185 HU, p < 0.017). For SUVmean, MARIS showed no significant effect in comparison with WFBP (WFBP: 0.99 ± 0.40, MARIS: 0.96 ± 0.39), while iMAR led to a significant decrease of 11.1% (0.88 ± 0.35, p < 0.017). Similar results were observed for dark band artifacts. CONCLUSION: iMAR significantly reduces artifacts caused by metal implants in CT and thus leads to a significant change of SUV measurements in bright and dark band artifacts compared with WFBP and MARIS, thus probably improving PET quantification. ADVANCES IN KNOWLEDGE: The present work indicates that MAR algorithms such as iMAR algorithm in integrated PET/CT scanners are useful to improve CT image quality as well as PET quantification in the evaluation of tracer uptake adjacent to large metal implants. A detailed analysis of oncological patients with various large metal implants using different MAR algorithms in PET/CT has not been conducted yet.


Assuntos
Artefatos , Metais , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons/métodos , Próteses e Implantes , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Idoso , Algoritmos , Feminino , Fluordesoxiglucose F18 , Humanos , Masculino , Imagens de Fantasmas , Estudos Prospectivos , Compostos Radiofarmacêuticos
13.
Br J Radiol ; 93(1105): 20181019, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31724436

RESUMO

OBJECTIVE: The aim of this phantom study was to investigate the effect of scan parameters and noise suppression techniques on the minimum radiation dose for acceptable image quality for CT emphysema densitometry. METHODS: The COPDGene phantom was scanned on a third generation dual-source CT system with 16 scan setups (CTDIvol 0.035-10.680 mGy). Images were reconstructed at 1.0/0.7 mm slice thickness/increment, with three kernels (one soft, two hard), filtered backprojection and three grades of third-generation iterative reconstruction (IR). Additionally, deep learning-based noise suppression software was applied. Main outcomes: overlap in area of the normalized histograms of CT density for the emphysema insert and lung material, and the radiation dose required for a maximum of 4.3% overlap (defined as acceptable image quality). RESULTS: In total, 384 scan reconstructions were analyzed. Decreasing radiation dose resulted in an exponential increase of the overlap in normalized histograms of CT density. The overlap was 11-91% for the lowest dose setting (CTDIvol 0.035mGy). The soft kernel reconstruction showed less histogram overlap than hard filter kernels. IR and noise suppression also reduced overlap. Using intermediate grade IR plus noise suppression software allowed for 85% radiation dose reduction while maintaining acceptable image quality. CONCLUSION: CT density histogram overlap can quantify the degree of discernibility of emphysema and healthy lung tissue. Noise suppression software, IR, and soft reconstruction kernels substantially decrease the dose required for acceptable image quality. ADVANCES IN KNOWLEDGE: Noise suppression software, IR, and soft reconstruction kernels allow radiation dose reduction by 85% while still allowing differentiation between emphysema and normal lung tissue.


Assuntos
Imagens de Fantasmas , Enfisema Pulmonar/diagnóstico por imagem , Doses de Radiação , Tomografia Computadorizada por Raios X/métodos , Humanos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos
14.
Medicine (Baltimore) ; 98(52): e18500, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31876738

RESUMO

Developmental dysplasia of the hip (DDH) is common, and features a widened Sharp's angle as observed on pelvic x-ray images. Determination of Sharp's angle, essential for clinical decisions, can overwhelm the workload of orthopedic surgeons. To aid diagnosis of DDH and reduce false negative diagnoses, a simple and cost-effective tool is proposed. The model was designed using artificial intelligence (AI), and evaluated for its ability to screen anteroposterior pelvic radiographs automatically, accurately, and efficiently.Orthotopic anterior pelvic x-ray images were retrospectively collected (n = 11574) from the PACS (Picture Archiving and Communication System) database at Second Hospital of Jilin University. The Mask regional convolutional neural network (R-CNN) model was utilized and finely modified to detect 4 key points that delineate Sharp's angle. Of these images, 11,473 were randomly selected, labeled, and used to train and validate the modified Mask R-CNN model. A test dataset comprised the remaining 101 images. Python-based utility software was applied to draw and calculate Sharp's angle automatically. The diagnoses of DDH obtained via the model or the traditional manual drawings of 3 orthopedic surgeons were compared, each based on the degree of Sharp's angle, and these were then evaluated relative to the final clinical diagnoses (based on medical history, symptoms, signs, x-ray films, and computed tomography images).Sharp's angles on the left and right measured via the AI model (40.07°â€Š±â€Š4.09° and 40.65°â€Š±â€Š4.21°), were statistically similar to that of the surgeons' (39.35°â€Š±â€Š6.74° and 39.82°â€Š±â€Š6.99°). The measurement time required by the AI model (1.11 ±â€Š0.00 s) was significantly less than that of the doctors (86.72 ±â€Š1.10, 93.26 ±â€Š1.12, and 87.34 ±â€Š0.80 s). The diagnostic sensitivity, specificity, and accuracy of the AI method for diagnosis of DDH were similar to that of the orthopedic surgeons; the diagnoses of both were moderately consistent with the final clinical diagnosis.The proposed AI model can automatically measure Sharp's angle with a performance similar to that of orthopedic surgeons, but requires far less time. The AI model may be a viable auxiliary to clinical diagnosis of DDH.


Assuntos
Luxação Congênita de Quadril/diagnóstico por imagem , Pelve/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Inteligência Artificial , Criança , Luxação Congênita de Quadril/diagnóstico , Humanos , Pessoa de Meia-Idade , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Radiografia/métodos , Estudos Retrospectivos , Adulto Jovem
15.
J Comput Assist Tomogr ; 43(6): 877-883, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31688248

RESUMO

PURPOSE: This study aimed to prospectively compare the image quality and visibility of urinary stone on computed tomographic (CT) images at multiple radiation exposure levels from the same patient reconstructed with sinogram-affirmed iterative reconstruction (SAFIRE). METHODS: This study included 760 patients with urinary stone who underwent CT with simultaneous acquisition at 6 exposures per patient (100% filtered back projection, 75%, 50%, 37.5%, 25%, and 12.5% SAFIRE). Two radiologists independently assessed overall image quality, noise, and stone visibility by using a 5-point scale. Quantitative measurements, including the CT number, image noise, signal-to-noise ratio, contrast-to-noise ratio (CNR), and corresponding figure of merit (FOM), were compared for 100% versus 5 other radiation doses. RESULTS: Qualitative overall image quality, noise, and stone visibility according to the location were not inferior at 37.5% exposure compared with 100% exposure, except for the visualization of smaller stones <3 mm. The signal-to-noise ratio and CNR of CT images were increased at 50% exposure compared with 100% exposure. Computed tomographic images at 37.5% exposure reconstructed with SAFIRE had significantly more noise and a lower CNR compared with CT images reconstructed with filtered back projection, based on FOMnoise and FOMCNR. The size-specific dose estimation was 4.1 ± 0.8 mGy at 37.5% exposure. CONCLUSION: Computed tomography performed at 37.5% exposure with SAFIRE may be diagnostically acceptable for the detection of clinically relevant stone.


Assuntos
Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Cálculos Urinários/diagnóstico por imagem , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Doses de Radiação , Razão Sinal-Ruído , Tomografia Computadorizada por Raios X , Adulto Jovem
16.
J Comput Assist Tomogr ; 43(6): 948-952, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31688249

RESUMO

PURPOSE: This study aimed to evaluate the image quality and degree of metal artifact reduction using the new-generation gemstone spectral imaging (GSI) and metal artifact reduction software (MARs) and to demonstrate the optimal monochromatic energy level for dual-energy cerebral computed tomography angiography (CTA) in patients with intracranial aneurysm after endovascular treatment. MATERIAL AND METHODS: A total of 20 patients with cerebral aneurysms treated with coils or clips underwent CTA using gemstone spectral computed tomography. Artifact index was calculated at each energy level with and without MARs. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated on all axial images with MARs; subjective evaluation was done by using a 4-point scale and a 3-point scale for assessing noise and vessel contrast, respectively, and compared between the monochromatic energy levels. RESULTS: The artifact index value of group GSI-MARs was significantly lower than that of group GSI at each monochromatic energy level (all, P < 0.01). Contrast-to-noise ratio and SNR of the parent arteries decreased as the energy increased from 40 to 140 keV in group GSI-MARs (all, P < 0.01). Signal-to-noise ratio and CNR between each 2 adjacent monochromatic energy level showed significant difference (all, P < 0.01). Subjective evaluation showed that a monochromatic energy level between 40 and 70 keV provided the optimal image quality. CONCLUSION: Gemstone spectral imaging with MARs could reduce metal artifacts and improve the image quality of cerebral CTA after coil or clip treatment. The new generation of GSI could provide better CNR and SNR at lower energy level, and the best image quality was obtained at energy level 40 to 70 keV for GSI-MARs.


Assuntos
Procedimentos Endovasculares/métodos , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/cirurgia , Intensificação de Imagem Radiográfica/métodos , Adulto , Idoso , Artefatos , Angiografia por Tomografia Computadorizada , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Estudos Retrospectivos , Razão Sinal-Ruído , Software
17.
J Comput Assist Tomogr ; 43(6): 953-957, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31738201

RESUMO

PURPOSE: Compression of the sciatic nerve in its path along the piriformis muscle can produce sciatica-like symptoms. There are 6 predominant types of sciatic nerve variations with type 1 being the most common (84.2%), followed by type 2 (13.9%). However, there is scarce literature on the prevalence of sciatic nerve variation in those diagnosed with sciatica. MATERIALS AND METHODS: The charts of 95 patients clinically diagnosed with sciatica who had a magnetic resonance imaging of the pelvis/hip were retrospectively studied. All patients had T1-weighted axial, coronal, and sagittal images. Magnetic resonance imagings were interpreted separately by 2 board-certified fellowship-trained musculoskeletal radiologists to identify the sciatic nerve variant. RESULTS: Seven cases were excluded because of inadequate imaging. Of the remaining 88 patients, 5 had bilateral sciatica resulting in a sample size of 93 limbs. Fifty-two (55.9%) had type 1 sciatic nerve anatomy, 39 (41.9%) had type 2, and 2 (2.2%) had type 3. The proportions of type 1 and 2 variations were significantly different from the normal distribution (P < 0.001), whereas type 3, 4, 5, and 6 variants were not (P = 1.00). CONCLUSIONS: There is strong statistical significance regarding the relationship between sciatic nerve variation and the clinical diagnosis of sciatica. Preoperative magnetic resonance imaging can be considered in sciatica patients to prevent iatrogenic injury in pelvic surgery.


Assuntos
Síndrome do Músculo Piriforme/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Nervo Isquiático/diagnóstico por imagem , Ciática/diagnóstico por imagem , Diagnóstico Diferencial , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Estudos Retrospectivos , Nervo Isquiático/patologia , Tíbia/diagnóstico por imagem , Tíbia/inervação
18.
J Comput Assist Tomogr ; 43(6): 852-856, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31738204

RESUMO

OBJECTIVE: The objective of this study was to assess renal lesions measuring less than 20 Hounsfield units (HU) on noncontrast computed tomography (NCT). METHODS: Twenty-one (18.1%) of 116 consecutive pathologically proven renal cell carcinomas measured less than 20 HU on NCT and were compared with 40 confirmed benign cysts also measuring less than 20 HU. All lesions were assessed qualitatively (heterogeneous or homogenous) by 3 blinded readers and quantitatively with commercially available textural analysis software. Finally, a combined assessment was performed. RESULTS: Qualitative assessment performed well (sensitivity, 76%-90%; specificity, 70%-88%). Quantitative assessment revealed mean positive pixels as having the highest performance (area under the curve, 0.912; sensitivity, 90%; specificity, 80% at a cutoff value of 21). The combined assessment, using the mean positive pixel cutoff, improved the sensitivity (reader 1, 100%; reader 2, 95%; and reader 3, 95%). CONCLUSION: Qualitative and quantitative assessments have relatively good performance, but the combination can nearly eliminate renal cell carcinomas being missed on NCT.


Assuntos
Carcinoma de Células Renais/diagnóstico por imagem , Neoplasias Renais/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Diagnóstico Diferencial , Feminino , Humanos , Doenças Renais Císticas/diagnóstico por imagem , Masculino , Projetos Piloto , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X
19.
J Comput Assist Tomogr ; 43(6): 931-936, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31738207

RESUMO

OBJECTIVES: Breast imaging can offer great information about breast cancer heterogeneity. The purpose of this study was to analyze the relationship between apparent diffusion coefficient (ADC) values and various prognostic factors and investigate whether ADC values are useful for breast cancer diagnosis, evaluation of treatment response, and determination of prognosis. METHODS: A total of 111 cases of breast cancer were included in this study. Magnetic resonance findings were recorded according to the Breast Imaging Reporting and Data System magnetic resonance imaging lexicon. Diffusion-weighted imaging rim sign and minimum, maximum, and difference ADC values (ADCdiff) were also evaluated. RESULTS: ADCdiff was related to all prognostic factors such as histological grade, Ki-67, tumor size, molecular subtype, axillary node metastasis, lymphvascular invasion, internal enhancement pattern, intratumoral high T2 signal, peritumoral edema, and diffusion-weighted imaging rim sign, whereas minimum and maximum ADC values showed variable associations. CONCLUSIONS: Apparent diffusion coefficient values were shown to be correlated with many proven or possible prognostic factors of breast cancer. In particular, ADCdiff can reflect tumor heterogeneity and showed higher correlation.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos
20.
J Comput Assist Tomogr ; 43(6): 906-911, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31738213

RESUMO

The aim of this article was to review computed tomography angiography and magnetic resonance angiography of pulmonary atresia with ventricular septal defect. This disorder is a rare complex congenital heart disease. Preoperative imaging of pulmonary atresia with ventricular septal defect with computed tomography angiography and magnetic resonance angiography is important for complete anatomical delineation and planning for treatment. Preoperative imaging used for assessment of the main pulmonary artery (its size, valve, and confluence), aortopulmonary collaterals (its origin, insertion, course, and size), presence of patent ductus arteriosus, other sources of collaterals as bronchial and coronary arteries, and pattern of pulmonary arborization. Imaging can detect associated aortic, pulmonary venous and coronary anomalies, and other congenital heart disease. Postoperative imaging after unifocalization and stent is for assessment of patency, stenosis, and occlusion of stent or perivascular lesions as seroma.


Assuntos
Defeitos dos Septos Cardíacos/diagnóstico por imagem , Defeitos dos Septos Cardíacos/cirurgia , Atresia Pulmonar/diagnóstico por imagem , Atresia Pulmonar/cirurgia , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Cateterismo Cardíaco , Procedimentos Cirúrgicos Cardíacos , Angiografia por Tomografia Computadorizada , Humanos , Angiografia por Ressonância Magnética , Período Pós-Operatório , Período Pré-Operatório , Procedimentos Cirúrgicos Pulmonares
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA