Generative Adversarial Network-based Noncontrast CT Angiography for Aorta and Carotid Arteries.

Background Iodinated contrast agents (ICAs), which are widely used in CT angiography (CTA), may cause adverse effects in humans, and their use is time-consuming and costly. Purpose To develop an ICA-free deep learning imaging model for synthesizing CTA-like images and to assess quantitative and qualitative image quality as well as the diagnostic accuracy of synthetic CTA (Syn-CTA) images. Materials and Methods A generative adversarial network (GAN)-based CTA imaging model was trained, validated, and tested on retrospectively collected pairs of noncontrast CT and CTA images of the neck and abdomen from January 2017 to June 2022, and further validated on an external data set. Syn-CTA image quality was evaluated using quantitative metrics. In addition, two senior radiologists scored the visual quality on a three-point scale (3 = good) and determined the vascular diagnosis. The validity of Syn-CTA images was evaluated by comparing the visual quality scores and diagnostic accuracy of aortic and carotid artery disease between Syn-CTA and real CTA scans. Results CT scans from 1749 patients (median age, 60 years [IQR, 50-68 years]; 1057 male patients) were included in the internal data set: 1137 for training, 400 for validation, and 212 for testing. The external validation set comprised CT scans from 42 patients (median age, 67 years [IQR, 59-74 years]; 37 male patients). Syn-CTA images had high similarity to real CTA images (normalized mean absolute error, 0.011 and 0.013 for internal and external test set, respectively; peak signal-to-noise ratio, 32.07 dB and 31.58 dB; structural similarity, 0.919 and 0.906). The visual quality of Syn-CTA and real CTA images was comparable (internal test set, P = .35; external validation set, P > .99). Syn-CTA showed reasonable to good diagnostic accuracy for vascular diseases (internal test set: accuracy = 94%, macro F1 score = 91%; external validation set: accuracy = 86%, macro F1 score = 83%). Conclusion A GAN-based model that synthesizes neck and abdominal CTA-like images without the use of ICAs shows promise in vascular diagnosis compared with real CTA images. Clinical trial registration no. NCT05471869 © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Zhang and Turkbey in this issue.

Cardiac magnetic resonance for the early prediction of reverse left ventricular remodeling in patients with ST-segment elevation myocardial infarction.

OBJECTIVES: To evaluate the changes in cardiac magnetic resonance (CMR) characteristics and investigate the predictors of reverse left ventricular remodeling (r-LVR) in ST-segment elevation myocardial infarction (STEMI) patients. MATERIALS AND METHODS: Eighty-six STEMI patients (median 56 years) were retrospectively studied. The patients were divided into r-LVR and without r-LVR groups. CMR analysis included LV volume, infarct characteristics, and global and regional myocardial function. The strain and displacement were assessed by CMR-feature tracking. The predictors of r-LVR were analyzed by the logistic regression method. RESULTS: There were 37 patients in the r-LVR group and 49 patients in the without r-LVR group. At initial CMR, there was no difference in LV volume and global cardiac function between the two groups. However, the infarct zone radial and longitudinal displacements were higher in the r-LVR group (p < 0.05, respectively). At the second CMR, the r-LVR group showed higher LVEF, lower LV volume, and total enhanced mass (all p < 0.05). The infarct zone radial and circumferential strains and radial displacement were higher in the r-LVR group (all p < 0.05). The r-LVR group had better recovery of myocardial injury and function. Of note, microvascular obstruction (MVO) mass (odds ratio: 0.779 (0.613-0.989), p = 0.041) and infarct zone peak longitudinal displacement (PLD) (odds ratio: 1.448 (1.044-2.008), p = 0.026) were independent predictors of r-LVR. CONCLUSIONS: At initial CMR, there were no differences in global cardiac function between the two groups, but infarct zone displacements were higher in the r-LVR group. The r-LVR group had better recovery of cardiac function. In addition, MVO mass and infarct zone PLD were independent predictors of r-LVR. CLINICAL RELEVANCE STATEMENT: Our study assessed changes in cardiac structure, function, and tissue characteristics after STEMI by CMR, investigated the best predictors of r-LVR in STEMI patients, and laid the foundation for the development of new parameter-guided treatment strategies for STEMI patients. KEY POINTS: • At initial CMR, the reverse left ventricular remodeling (r-LVR) group had less myocardial damage and higher infarct zone displacement, but there were no differences in global function between the two groups. • Both groups showed recovery of myocardial injury and cardiac function over time, but the r-LVR group had less enhanced mass and better cardiac function compared to the without r-LVR group at the second CMR. • Microvascular obstruction mass and infarct zone peak longitudinal displacement by cardiac magnetic resonance feature-tracking were significant predictors of r-LVR in STEMI patients.

[Multiple Extracarciac Complications of Infective Endocarditis: Report of One Case].

Infective endocarditis is a microbial infection of the endocardium and can easily affect heart valve.Its characteristic lesion is vegetation formation,and the shedding of vegetation results in arterial embolism and ischemic necrosis of corresponding tissues and organs.A case of infective endocarditis with multiple extracardiac complications was described in this article.The characteristic ultrasound finding was the vegetation formation in anterior mitral valve.CT and MRI scans revealed involvements in multiple organs and blood vessels,which were manifested as splenic infarction,renal infarction,cerebral infarction,splenic aneurysm,superior mesenteric artery aneurysms,renal artery aneurysms,and distal segment stenosis and occlusion of right middle cerebral artery.

[Effect of Monochromatic Energy Image Synthesized from Dual-layer Detector Spectral CT on Imaging of Inferior Vena Cava].

Objective To evaluate the effect of monochromatic energy image on inferior vena cava imaging quality on dual-layer detector spectral CT. Methods Totally 39 patients who were clinically suspected of abdominal disease and referred to perform contrast-enhanced computed tomography(CT)were prospectively enrolled and underwent abdominal examination using a single-source,dual-detector spectral CT.The delayed phase scan was performed 3 minutes after injection of 60 ml of iopamidol(320 mg/ml)at a rate of 3 ml/s.The raw images were reconstructed to obtain conventional mixed energy images and spectral based images(SBI).The 40,50,60,and 70 keV single energy images were obtained.The CT value,noise,and signal-to-noise(SNR)of inferior vena cava and the contrast-to-noise(CNR)of inferior vena cava relative to psoas major on conventional mixed energy images and the 40,50,60,70 keV single energy images were measured.The SNRs and CNRs on monoenergetic 40-70 keV images were compared with polychromatic 120 kVp images.ANOVA was used to compare the CT value,noise,SNR,and CNR among these five groups.The optimal monoenergetic image set was chosen. Results The differences in CT value,noise,SNR,CNR of inferior vena cava were statistically significant among five groups(all P<0.05).The SNR and CNR in 40 keV group and 50 keV group were significantly higher than those in other groups(all P<0.05).The SNR of 40 keV group was significantly higher than that of 50 keV group(P=0.002).The CNR of 40 keV group was not statistical different compared with that of 50 keV group(P=0.630). Conclusion 40 keV is the optimal monoenergetic energy level for the inferior vena cava on dual-layer detector spectral CT and may be valuable for the diagnosis of inferior vena cava disease.

Midterm Follow-up of Coronary Artery Bypass Grafting with 64-Slice Multi-detector Computed Tomography: Identification of Risk Factors Affecting Graft Patency.

To identify the risk factors that are associated with the midterm coronary artery bypass grafting (CABG) functionality by assessing patency of left internal mammary artery (LIMA) graft and saphenous vein (SV) graft with 64-slice multi-detector computed tomography (64-MDCT).Methods Patients who underwent CABG operation and postoperative 64-MDCT follow-up examinations from August 2012 to December 2015 were included. The graft patent status was classified into patent and poor patent according to MDCT findings predominantly on 3D reconstructed images by two radiologists. The clinical data and imaging findings of the patients were collected and compared between the patent group and poor patent group. Univariate analysis and the multivariate logistic regression analysis were performed to identify the risk factors that affect graft patency.Results Among 341 patients in the study, there were 330 LIMA grafts [326 anastomosed to the left anterior descending artery (LAD), 4 to right coronary artery (RCA)] and 564 SV grafts (SVG) [100 anastomosed to the diagonal branch (D), 226 to the obtuse marginal branch (OM), and 238 to the RCA territory]. The approximal vessel stenosis exceeding 90% occurred in 268 of 292 patent LIMA grafts, and in 1 of 34 poor patent grafts (χ 2=167, P<0.001). The patency rate was higher when SVG was anastomosed to OM (85.4%) or RCA territory (81.9%) than to D (69.0%) (χ 2=15.471, P=0.004). The proximal target vessel stenosis < 90% (OR= 0.015, 95% CI: 0.01-0.14, P=0.000) was independently associated with the closure risk of LIMA grafts, the dyslipidemia (OR= 1.52, 95% CI: 1.0-2.5, P=0.048), history of diabetes (OR = 1.28, 95% CI : 0.90-2.26, P=0.045) and typical angina symptoms (OR=1.81, 95% CI :1.33-4.15, P=0.003) were independently associated with the closure risk of SVG. Conclusions The proximal LAD stenosis less than 90% was adversely associated with graft patency in LIMA recipients; dyslipidemia, diabetes and angina symptoms were associated with the midterm failure in SVG recipients. The choice of the target anastomosis sites may affect the patency of SVG.

Value of Multi-detector CT in Detection of Isolated Spontaneous Superior Mesenteric Artery Dissection.

Objective To investigate the role of multi-detector computed tomography (CT) in the diagnosis and classification of isolated spontaneous superior mesenteric artery dissection (ISSMAD). Methods From July 2012 to December 2016, 30 consecutive patients with ISSMAD underwent CT scan at least two times. We retrospectively summarized the clinical characteristics and CT findings of them. The stenosis ratio of true lumen was compared between the patients without bowel ischemia and ones with bowel ischemia. Results There were 5 cases of type I ISSMAD, 14 cases of type 2, 1 case of type 3, 7 cases of type 4 and 3 cases of type V. Intestinal ischemia occurred in 5 patients. The stenosis ratio of true lumen in the patients without bowel ischemia was lower than that with bowel ischemia (45.6% vs. 76.0%, t=-14.5, P=0.000). Five patients with intestinal ischemia underwent superior mesenteric artery stenting and others received conservative therapy. The abdominal pain was alleviated for all the patients after treatment. Follow-up was complete in 30 cases. Follow-up CT angiography of superior mesenteric artery showed dissection remodeling in 12 patients. Conclusion Multi-detector CT is a valuable method in diagnosis and classification of ISSMAD and monitoring the changes of dissection.

Coronary CT Angiography with Knowledge-Based Iterative Model Reconstruction for Assessing Coronary Arteries and Non-Calcified Predominant Plaques.

OBJECTIVE: To assess the effects of iterative model reconstruction (IMR) on image quality for demonstrating non-calcific high-risk plaque characteristics of coronary arteries. MATERIALS AND METHODS: This study included 66 patients (53 men and 13 women; aged 39-76 years; mean age, 55 ± 13 years) having single-vessel disease with predominantly non-calcified plaques evaluated using prospective electrocardiogram-gated 256-slice CT angiography. Paired image sets were created using two types of reconstruction: hybrid iterative reconstruction (HIR) and IMR. Plaque characteristics were compared using the two algorithms. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the images and the CNR between the plaque and adjacent adipose tissue were also compared between the two reformatted methods. RESULTS: Seventy-seven predominantly non-calcified plaques were detected. Forty plaques showed napkin-ring sign with the IMR reformatted method, while nineteen plaques demonstrated napkin-ring sign with HIR. There was no statistically significant difference in the presentation of positive remodeling, low attenuation plaque, and spotty calcification between the HIR and IMR reconstructed methods (all p > 0.5); however, there was a statistically significant difference in the ability to discern the napkin-ring sign between the two algorithms (χ² = 12.12, p < 0.001). The image noise of IMR was lower than that of HIR (10 ± 2 HU versus 12 ± 2 HU; p < 0.01), and the SNR and CNR of the images and the CNR between plaques and surrounding adipose tissues on IMR were better than those on HIR (p < 0.01). CONCLUSION: IMR can significantly improve image quality compared with HIR for the demonstration of coronary artery and atherosclerotic plaques using a 256-slice CT.

Establishment of a Large Animal Model for Eustachian Tube Functional Study in Miniature Pigs.

This study was performed to investigate whether miniature pigs are a suitable animal model for studies of the Eustachian tube (ET). Sixteen Chinese experimental miniature pigs were used in this investigation. Ten animals were used for anatomical and morphometric analyses to obtain qualitative and quantitative information regarding the ET. Three animals were used for histological analysis to determine the fine structure of ET cross-sections. Three animals were used to investigate the feasibility of balloon dilation of the Eustachian tube (BDET). The anatomical study indicated that the pharyngeal orifice and tympanic orifice of the miniature pig ET are located at the posterior end of the nasal lateral wall and anterior wall of the middle ear cavity, respectively. The cartilaginous tube was seen to pass through the whole length of the ET, the length of the cartilaginous part of the ET and the diameter of the isthmus were similar between humans and miniature pigs. The inclination of the ET in miniature pigs was larger than that in humans. The gross histology seemed to be slightly different between miniature pig and human, but the fine structures were essentially the same in both species. BDET experiments verified that the miniature pig model is suitable as a model for clinical operations. The miniature pig ET corresponds very well to that of humans. In addition, the miniature pig ET is suitable as a model for clinical operations. Therefore, the miniature pig is a valid animal model for ET study. Anat Rec, 302:1024-1038, 2019. © 2019 Wiley Periodicals, Inc.

[Application progress of digital technology in auricle reconstruction].

Objective: To review the application progress of digital technology in auricle reconstruction. Methods: The recently published literature concerning the application of digital technology in auricle reconstruction was extensively consulted, the main technology and its specific application areas were reviewed. Results: Application of digital technology represented by three-dimensional (3D) data acquisition, 3D reconstruction, and 3D printing is an important developing trend of auricle reconstruction. It can precisely guide auricle reconstruction through fabricating digital ear model, auricular guide plate, and costal cartilage imaging. Conclusion: Digital technology can improve effectiveness and decrease surgical trauma in auricle reconstruction. 3D bioprinting of ear cartilage future has bright prospect and needs to be further researched.

[Application of multislice computed tomography volume rendering and 3D printing technique of costal cartilage for auricular reconstruction].

Objective: To investigate the value of Multislice computed tomography volume rendering(VR) technique and 3D printing technique in auricular reconstruction. Methods: Six patients were enrolled for auricular reconstruction with costal cartilage,including 5 congenital microtia patients and 1 traumatic auricular defect patient. We harvest the three-dimensional reconstructive data of the contralateral sixth, seventh, eighth and ninth costal cartilage with VR technique.Three-dimensional solid models were 3D printed with nylon material according to the data exported in STL format.Preoperativesimulation was performed on the models, accordingly, we determined the strategies of costal cartilage harvest and framework fabrication, and operations were performed based on the pre-designed plan. Results: In all 6 patients, the actual costal cartilage harvest and framework fabrication process was consistent with the preoperative design and simulation results, and more scientific than before.The shapes of reconstructed ears were vivid and natural. No complications such as infection,absorption,distortion and chest deformity happened. Conclusions: Through costal cartilage VR and 3D printing technique, we could make more reasonable preoperative design and simulation. The results can be improved with reduced injury, while avoiding the risks of thoracic deformity.