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Recently in diagnosis of Aortic dissection (AD), the synthesis of contrast enhanced CT (CE-CT) images from non-contrast CT (NC-CT) images is an important topic. Existing methods have achieved some results but are unable to synthesize a continuous and clear intimal flap on NC-CT images. In this paper, we propose a multi-stage cascade generative adversarial network (MCGAN) to explicitly capture the features of the intimal flap for a better synthesis of aortic dissection images. For the intimal flap with variable shapes and more detailed features, we extract features in two ways: dense residual attention blocks (DRAB) are integrated to extract shallow features and UNet is employed to extract deep features; then deep features and shallow features are cascaded and fused. For incomplete flaps or lack of details, we use spatial attention and channel attention to extract key features and locations. At the same time, multi-scale fusion is used to ensure the continuity of the intimal flap. We perform the experiment on a set of 124 patients (62 with AD and 62 without AD). The evaluation results show that the synthesized images have the same characteristics as the real images and achieves better results than the popular methods., (© 2024. The Author(s).)

Background & Objective: Aortic dissection (AD) is a serious condition requiring rapid and accurate diagnosis. In this study, we aimed to improve the diagnostic accuracy of AD by presenting a novel method for aortic segmentation in computed tomography images that uses a combination of a transformer and a UNet cascade network with a Zoom-Out and Zoom-In scheme (ZOZI-seg)., Methods: The proposed method segments each compartment of the aorta, comprising the true lumen (TL), false lumen (FL), and thrombosis (TH) using a cascade strategy that captures both the global context (anatomical structure) and the local detail texture based on the dynamic patch size with ZOZI schemes. The ZOZI-seg model has a two-stage architecture using both a "3D transformer for panoptic context-awareness" and a "3D UNet for localized texture refinement." The unique ZOZI strategies for patching were demonstrated in an ablation study. The performance of our proposed ZOZI-seg model was tested using a dataset from Asan Medical Center and compared with those of existing models such as nnUNet and nnFormer., Results: In terms of segmentation accuracy, our method yielded better results, with Dice similarity coefficients (DSCs) of 0.917, 0.882, and 0.630 for TL, FL, and TH, respectively. Furthermore, we indirectly compared our model with those in previous studies using an external dataset to evaluate its robustness and generalizability., Conclusions: This approach may help in the diagnosis and treatment of AD in different clinical situations and provide a strong basis for further research and clinical applications., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Spontaneous isolated visceral artery dissection (SIVAD) is rare. Recently, appropriate treatment strategies for symptomatic SIVAD have been proposed. We aimed to determine the management of asymptomatic spontaneous isolated superior mesenteric artery dissection (ASISMAD), which is relatively frequently encountered in SIVAD., Methods: We retrospectively reviewed abdominal contrast-enhanced computed-tomography (CE-CT) scans from January 2015 to December 2020 in our institution and identified 24 patients with ASISMAD. Patient characteristics, vascular risk factors, complications, morphology features on CE-CT images, changes in abdominal CE-CT, and treatments outcomes were analyzed., Results: All patients were male. The mean age of the patients was 66.0 ± 8.9 (standard deviation) years, and the follow-up period was 24.8 ± 28.7 months. The CE-CT images revealed that 1 patient had periarterial fat stranding, 15 patients had aneurysmal dilatation, and 7 patients had branch vessel involvement. The mean length of the dissection was 19.9 ± 13.5 mm. The mean distance from the orifice of the superior mesenteric artery to the dissection origin point was 14.9 ± 8.8 mm. The mean branching angle was 54.8°± 19.7°. None of the patients had dissection-related abdominal symptoms or complications. Follow-up CE-CT scans showed progression of the dissection in 2 (8.3%), improvement in 2 (8.3%), stable dissection in 17 (70.9%), and complete remodeling in 3 (12.5%)., Conclusions: Patients with ASISMAD do not require hospitalization because the pathology does not usually progress to visceral ischemia. Nevertheless, follow-up CE-CT is required because of progression of the dissection in rare cases.

Purpose: Currently, Computed Tomography Angiography (CTA) is the most commonly used clinical method for the diagnosis of aortic dissection, which is much better than plain CT. However, CTA examination has some disadvantages such as time-consuming image processing, complicated procedure and injection of developer. CT plain scanning is widely used in the early diagnosis of arterial dissection because of its convenience, speed and popularity. In order not to delay the optimal diagnosis and treatment time of patients, we use deep learning technology and network model to synthesize plain CT images into CTA images. Patients can be timely professional related departments of clinical diagnosis and treatment, and reduce the rate of missed diagnosis. In this paper, we propose a CTA image synthesis technique for cardiac aortic dissection based on the cascaded generative adjunctive network model., Method: Firstly, we registered CT images, and then used nnU-Net segmentation network model to obtain CT and CTA paired images containing only the aorta. Then we proposed a CTA image synthesis method for aortic dissection based on cascaded generative adversarial. The core idea is to build a cascade generator and double discriminator network based on DCT channel attention mechanism to further enhance the synthesis effect of CTA., Results: The model is trained and tested on CT plain scan and CTA image data set of aortic dissection. The results show that the proposed model achieves good results in CTA image synthesis. In the CT data set, the nnU-Net model improves 8.63% and reduces 10.87mm errors in the key index DSC and HD, respectively, compared with the benchmark model U-Net. In CTA data set, nnU-Net model improves 10.27% and reduces 6.56mm error in key index DSC and HD, respectively, compared with benchmark model U-Net. In the synthesis task, the cascaded generative adm network is superior to Pix2pix and Pix2pixHD network models in both PSNR and SSIM, which proves that our proposed model has significant advantages., Conclusion: This study provides new possibilities for CTA image synthesis of aortic dissection, and improves the accuracy and efficiency of diagnosis, and hopes to provide substantial help for the diagnosis of aortic dissection., Competing Interests: Declaration of Competing Interests The authors declare no conflict of interests in this paper., (Copyright © 2022. Published by Elsevier B.V.)

Abstract: The differences between the pathologies of cases of type A acute aortic dissection (AAD) that did and did not result in prehospital death (PHD) have not been fully elucidated.This study aimed to compare the CT findings and clarify the differences between the pathologies of such cases.Ninety four consecutive type A AAD patients between 2010 and 2020 were enrolled in this study. There were 47 males and 47 females (mean age: 69.0 ± 14.4 years). The patients were divided into those that did (n = 25, 27%) and did not (n = 69, 73%) suffer PHD. We retrospectively evaluated the CT or postmortem CT findings of each case and analyzed the relationships between clinical factors (CT findings and clinical characteristics) and PHD using logistic regression analysis.Bloody pericardial effusion (96% vs 35%, P < .0001), bloody pleural effusion (40% vs 1%, P < .0001), and mediastinal hematomas (88% vs 14%, P < .0001) were significantly more common in the PHD group than in the no PHD group.In the multivariate logistic regression analysis, bloody pericardial effusion and lung consolidation were found to be significant risk factors for PHD (odds ratio: 21.29 [95% confidence intervals {CI}: 1.19-248.29] and 13.72 [95% CI: 1.79-105.06], respectively; P = .014 and P  = .012, respectively). AD affecting the abdominal aorta was identified as a significant negative risk factor for PHD (odds ratio: 0.02 [95% CI: 0.01-0.65]; P = .0042).Most PHD due to type A AAD are associated with hemorrhaging. Bleeding into the pericardium and type A AAD confined to the thoracic aorta are significant risk factors for PHD. Secondary respiratory failure might contribute to PHD in such cases., Competing Interests: The authors have no conflicts of interests to disclose., (Copyright © 2022 the Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: To develop a non-contrast CT-based radiomic signature to effectively screen for thoracic aortic dissections (ADs)., Methods: We retrospectively enrolled 378 patients who underwent non-contrast chest CT scans along with CT angiography or MRI from 4 medical centers. The training and validation sets were from 3 centers, while the external test set was from a 4th center. Radiomic features were extracted from non-contrast CT images. The radiomic signature was created on the basis of selected features by a logistic regression algorithm. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve, accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were conducted to assess the predictive ability of radiomic signature., Results: The radiomic signature demonstrated AUCs of 0.91 (95% confidence interval [CI], 0.86-0.95) in the training set, 0.92 (95% CI, 0.86-0.98) in the validation set, and 0.90 (95% CI, 0.82-0.98) in the external test set. The predicted diagnosis was in good agreement with the probability of thoracic AD. In the external test group, the diagnostic accuracy, sensitivity, specificity, PPV, and NPV were 90.5%, 85.7%, 91.7%, 70.6%, and 96.5%, respectively., Conclusions: A radiomic signature based on non-contrast CT images can effectively predict thoracic ADs. This method may serve as a potential screening tool for thoracic ADs., Key Points: • The non-contrast CT-based radiomic signature can effectively predict the thoracic aortic dissections. • This radiomic signature shows better predictive performance compared to the current clinical model. • This prediction method may be a potential tool for screening thoracic aortic dissections., (© 2021. European Society of Radiology.)

Abstract: To investigate the diagnostic value of a computed tomography (CT) scan-based radiomics model for acute aortic dissection.For the dissection group, we retrospectively selected 50 patients clinically diagnosed with acute aortic dissection between October 2018 and November 2019, for whom non-contrast CT and CT angiography images were available. Fifty individuals with available non-contrast CT and CT angiography images for other causes were selected for inclusion in the non-dissection group. Based on the aortic dissection locations on the CT angiography images, we marked the corresponding regions-of-interest on the non-contrast CT images of both groups. We collected 1203 characteristic parameters from these regions by extracting radiomics features. Subsequently, we used a random number table to include 70 individuals in the training group and 30 in the validation group. Finally, we used the Lasso regression for dimension reduction and predictive model construction. The diagnostic performance of the model was evaluated by a receiver operating characteristic (ROC) curve.Fourteen characteristic parameters with non-zero coefficients were selected after dimension reduction. The accuracy, sensitivity, specificity, and area under the ROC curve of the prediction model for the training group were 94.3% (66/70), 91.2% (31/34), 97.2% (35/36), and 0.988 (95% confidence interval [CI]: 0.970-0.998), respectively. The respective values for the validation group were 90.0% (27/30), 94.1% (16/17), 84.6% (11/13), and 0.952 (95% CI: 0.883-0.986).Our non-contrast CT scan-based radiomics model accurately facilitated acute aortic dissection diagnosis., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Hemorrhagic extension along the pulmonary arteries should be recognized as a complication of Stanford type A aortic dissection. Radiologists and other physicians with an interest in cardiothoracic imaging should be aware of this rare but life-threatening pathology. The anatomical concept of the pathology is outlined in this text, through high-quality electrocardiogram-gated computerized tomography images., (© 2020 Wiley Periodicals LLC.)

Background: This study investigated whether anatomical factors affect the occurrence of SISMAD by measuring the aortomesenteric angle (AMA)., Methods: The study population is comprised of 3 distinct population; Korean SISMAD patients, two control groups from a medical checkup database of 4997 Korean and 317 Caucasian patients from 2011 to 2016. The patient group (PG) included 26 symptomatic patients and 19 Korean diagnosed with SISMAD during medical checkup. The control group was selected based on propensity score similarities calculated by using the following covariates: sex, age, body mass index, drinking, smoking, hypertension, diabetes, and cancer. We compared PG with equal numbers of two control groups comprised of Koreans (KG) and Caucasians (FG), respectively., Results: The mean (SD) AMA was 74.9o (17.5) (range, 45.9-110.9o) in the PG, 56.8o (19.5 (range, 10.2o -91.9o) in the FG, and 62.4o (19.1) (range, 25.4-110.8o) in the KG. A significant difference was observed between PG and the two control groups (P<0.001). The AMA in the FG was significantly more acute than the AMA in Korean patients including those in the PG and KG (P=0.001)., Conclusions: Large AMA is considered to be an important etiologic factor in SISMAD.

Aortic dissections and ruptures are life-threatening injuries that must be immediately treated. Our national radiology practice receives dozens of these cases each month, but no automated process is currently available to check for critical pathologies before the images are opened by a radiologist. In this project, we developed a convolutional neural network model trained on aortic dissection and rupture data to assess the likelihood of these pathologies being present in prospective patients. This aortic injury model was used for study prioritization over the course of 4 weeks and model results were compared with clinicians' reports to determine accuracy metrics. The model obtained a sensitivity and specificity of 87.8% and 96.0% for aortic dissection and 100% and 96.0% for aortic rupture. We observed a median reduction of 395 s in the time between study intake and radiologist review for studies that were prioritized by this model. False-positive and false-negative data were also collected for retraining to provide further improvements in subsequent versions of the model. The methodology described here can be applied to a number of modalities and pathologies moving forward.

Background: Acute type A aortic dissection (ATAD) remains associated with substantial short-term mortality, and despite increasing rates of surgical repair, as many as 10% to 20% of patients do not undergo surgery because of comorbidities and dissection-related complications. For patients unable to undergo open repair, previous attempts at endovascular treatment of ATAD used devices originally designed for deployment in the descending thoracic aorta. Industry has begun to support early investigational devices meant specifically for placement within the ascending aorta. We evaluated relevant aortic parameters to examine which patients may be candidates for repair with an ascending aortic endograft., Methods: We reviewed 100 consecutive patients in our institutional ATAD database with contrast-enhanced computed tomography imaging on an Aquarius iNtuition workstation (TeraRecon, San Mateo, Calif), using curved planar reformatting (vessel tracking) and orthogonal views for measurements. We compared relevant aortic measurements against proposed criteria for future ascending endografts, including various landing zone diameters and intimal tear distances from the distal coronary ostium., Results: Of the 100 patients examined, 39% had proximal intimal tears located outside the tubular ascending aorta. In all, 30% were excluded on the basis of either the presence of a prosthetic aortic valve or significant aortic insufficiency, and 6% were excluded on the basis of the presence of patent coronary artery bypass grafts from the ascending aorta. Many patients had multiple exclusion criteria, and based on various proposed criteria, overall candidacy ranged from 2% to 23%. If a maximum landing zone diameter of 42 mm and intimal tears as little as 20 mm distal to the distalmost coronary were considered treatable, only 8% of patients would have been candidates compared with 20% candidacy if aortic diameters up to 46 mm and intimal tears as little as 10 mm distal to the distalmost coronary were considered treatable. The most frequent single cause for exclusion was inadequacy of the proximal landing zone. Iliofemoral vascular access was also assessed and deemed adequate in >90% of cases., Conclusions: A minority of patients suffering ATAD would currently qualify for ascending aortic endografting on the basis of anatomic criteria alone. Future device designs should take into account these common anatomic exclusion criteria so that more versatile devices may be developed and commercially available to treat a larger number of patients., (Copyright © 2019 Society for Vascular Surgery. All rights reserved.)

Competing Interests: All authors have disclosed no conflicts of interest.

This is the 39th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at http://www.erad.org/page/CCIP&#95;TOC .

Objective: Sarcopenia, as assessed by computed tomography (CT)-based measurements of muscle mass, is an objective and patient-specific indicator of frailty, which is an important predictor of operative morbidity and mortality. Studies to date have primarily focused on psoas-defined sarcopenia, which may not be valid among patients with thoracic aortic disease. Using psoas sarcopenia as the reference for sarcopenia, the purpose of this study was to create and to validate a new thoracic-level method of measuring sarcopenia as a novel method to assess frailty among patients undergoing thoracic endovascular aortic repair., Methods: Prospectively collected data of patients undergoing thoracic endovascular aortic repair for thoracic aortic dissection, aneurysm, or injury using a conformable thoracic graft were reviewed. Patients with preoperative abdominal and thoracic CT imaging were included. Thoracic muscle mass was measured on axial images at the T12 level using our newly established standardized computer-assisted protocol. Psoas sarcopenia was measured at the L3 level using standard methods. Optimal sex-specific diagnostic T12 measurements were determined by receiver operating characteristic (ROC) curve analysis. A subset of scans were reviewed in duplicate by two trained observers and intraobserver and interobserver reliability tested by intraclass correlation coefficient. Agreement between T12 and L3 sarcopenia was tested by Cohen κ (scale, 0-1)., Results: There were 147 patients included for analysis, including 34 dissection, 80 trauma, and 33 aneurysm patients. ROC curve analysis yielded sarcopenic cutoff values of 106.00 cm 2 /m 2 for women and 110.00 cm 2 /m 2 for men at the T12 level. Based on ROC curve analysis, overall accuracy of T12 measurements was high (area under ROC curve, 0.91 for men and 0.90 for women). Quantitative interobserver and intraobserver reliability yielded excellent intraclass correlation coefficient values (>0.95). Qualitative interobserver reliability yielded nearly perfect Cohen κ values (>0.85). Qualitative intraobserver reliability of calculating sarcopenia at both the T12 and L3 levels was fair for both readers (0.361 and 0.288). There was additionally a general correlation between changes in muscle area at L3 with changes at T12 during 48 months., Conclusions: Thoracic sarcopenia can be readily and reliably reproduced from CT-derived measurement of T12-level muscle area. This approach may be used as an alternative method to objectively define sarcopenia in patients without abdominal CT imaging. Future studies to assess the predictability of thoracic vs abdominal sarcopenia on postoperative outcomes will enhance the utility of these tools., (Copyright © 2018 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Spontaneous superior mesenteric artery (SMA) dissection is rare cause of acute abdomen. Time-dependent change of SMA dissection has not been established., Purpose: To determine Sakamoto classification (SC) type of acute and chronic SMA dissection (aSMAD and cSMAD) to predict the treatment methods and outcome., Material and Methods: From April 2003 to March 2017, unenhanced and contrast-enhanced CT were used to diagnose acute symptomatic or chronic asymptomatic SMA dissection in 25 consecutive patients without aortic dissection. Correlations between SCs and treatment methods and outcomes were investigated., Results: All 13 patients with aSMAD initially received conservative treatment. Initial SCs in aSMAD were type I = 1, type III = 9, and type IV = 3. Three of nine initial type III and two of three initial type IV changed to type I at follow-up. One of nine type III changed to type II at follow-up. Ohers did not change. One with initial type III required vascular repair, so the final SC was not available. Three patients required bowel resection. In cSMAD of 12 patients, the initial/final SC were type I and IV in ten and two patients, respectively, without change during follow-up. cSMAD was significantly older than aSMAD. The initial length of dissection of aSMAD was longer than in the cSMAD group. In aSMAD, the final length of dissection was significantly shorter than in the initial computed tomography scan., Conclusion: Initial SC differed significantly between aSMAD and cSMAD. Initial SC types in aSMAD were type III and IV mainly, and changed during the observation period. In cSMAD, SC types were I and IV without change.

Objectives: To examine the correlation between computed tomography (CT) features and clinical presentation and to assess the management strategy for patients with isolated superior mesenteric artery (SMA) dissection., Material and Methods: Retrospective analysis of clinical records and CT findings of patients with isolated superior mesenteric artery dissection treated between 2012 and 2016. The relationship between CT features and clinical symptoms and treatment options was studied. Follow up CT images were reviewed and telephone interviews were conducted with patients., Results: Sixty-nine patients with isolated SMA dissection (47 symptomatic and 22 asymptomatic) were evaluated. The dissection length in patients with Sakamoto type IV lesions was significantly longer than that in patients with other lesion types (83.0 ± 40.1 mm, p = .001). Compared with the asymptomatic group, the symptomatic group had longer dissections (63.5 ± 35.9 mm, p < .001) and lesser true lumen diameter (3.1 ± 1.7 mm, p = .044). Fifty-six patients were treated conservatively, of whom 31 showed clinical improvement and exhibited no morphological change during long-term follow up., Conclusions: In patients with isolated SMA dissection, clinical symptoms were related to the length of dissection and degree of true lumen stenosis. Conservative treatment was commonly employed and yielded favourable outcomes., (Copyright © 2018 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.)

The purpose of this study is to evaluate the hemodynamic characteristics of the true lumen (TL) and the false lumen (FL) in 16 patients with aortic dissection (AD) using 4D flow magnetic resonance imaging (MRI) and thoracic and abdominal computed tomography (CT) angiography. The quantitative parameters that were measured in the TL and FL included velocity and flow. The mean area and regurgitant fraction of the TL were significantly lesser at all four levels (p < 0.05); the average through-plane velocity, peak velocity magnitude, average net flow, peak flow, and net forward volume in the TL were considerably higher (p < 0.05). The intimal entry's size was negatively correlated with the blood flow velocity and flow rate in the TL (p < 0.05) and positively correlated with the average through-plane velocity, average net flow, and peak flow in the FL (p < 0.05); the blood flow indices in the TL were enhanced with an increase in the intimal entry numbers (p < 0.05) and the peak flow in the FL was lowered (p = 0.025); if FL thrombosis existed, the average through-plane velocity and peak velocity magnitude in the TL were substantially higher (p < 0.05). 4D flow MRI facilitates qualitative and quantitative analysis of the alterations in the abdominal aortic blood flow patterns.

Introduction: Acute aortic dissection (AAD) is a life-threatening condition making early diagnosis critical. Although 90% present with acute pain, the myriad of associated symptoms can make diagnosis a challenge. Our objective was to assess how we are using computed tomography to rule out acute aortic dissection specifically rate of ordering, diagnostic yield, and variation in practice., Methods: We included consecutive adult patients presenting to two tertiary academic care emergency departments over one calendar year presenting with non-traumatic chest, back, abdominal, or flank pain. Primary outcome was rate of CT thorax/abdomen ordered to rule out AAD. Secondary outcome was variation in CT ordering, measured comparing number of CTs ordered per physician. Sample size of 12 per group was calculated based on an expected delta in mean CT ordered of 5 and a within group SD of 3., Results: Thirty-one thousand two hundred one patients presented with truncal pain during the study period, 22,729 were included (mean 47 years, SD 18.5 years, 56.2% female); prevalence of AAD (N = 4) was 0.02%. CT was ordered to rule out AAD in 175 (0.7%) patients (mean 62 years, SD 16.5, 50.6% female). Significant variation between physicians ordering was found, with individual physicians ordering varying from 0.6 to 12%., Conclusions: Current rate of imaging for acute aortic dissection is low and potentially inefficient, with a large variation in practice. These findings suggest potential for more standardized and efficient use of CT for the diagnosis of acute aortic dissection.

Background and Purpose: Accurate diagnosis of acute aortic dissection (AAD) is sometimes difficult because of accompanying central nervous system (CNS) symptoms. The purpose of this study was to investigate the clinical characteristics of Type A AAD (TAAAD) with CNS symptoms., Methods: We retrospectively reviewed the medical records of 8403 patients ambulanced to our emergency and critical care center between April 2009 and May 2014., Results: We identified 59 TAAAD patients for the analysis (mean age, 67.3±10.5years; 37 (62.0%) male). Eleven patients (18.6%) presented CNS symptoms at the onset of TAAAD, and these patients complained less frequently of typical chest and back pain than those without CNS symptoms (p<0.0001). Initial systolic and diastolic blood pressure were lower (p=0.003, and p=0.049, respectively) and involvement of the supra-aortic artery was more frequent in patients with CNS symptoms (p<0.0001)., Conclusion: Because CNS symptom can mask chest and back pain caused by TAAAD, physicians should always consider the possibility of TAAAD in patients with CNS symptoms in emergency medicine settings., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Spontaneous cervical artery dissection (sCAD) is an important etiology of juvenile stroke. The gold standard for the diagnosis of sCAD is convential angiography. However, magnetic resonance imaging (MRI)/MR angiography (MRA) and computed tomography (CT)/CT angiography (CTA) are frequently used alternatives. New developments such as multislice CT/CTA have enabled routine acquisition of thinner sections with rapid imaging times. The goal of this study was to compare the capability of recent developed 128-slice CT/CTA to MRI/MRA to detect radiologic features of sCAD., Methods: Retrospective review of patients with suspected sCAD (n = 188) in a database of our Stroke center (2008-2014), who underwent CT/CTA and MRI/MRA on initial clinical work-up. A control group of 26 patients was added. All Images were evaluated concerning specific and sensitive radiological features for dissection by two experienced neuroradiologists. Imaging features were compared between the two modalities., Results: Forty patients with 43 dissected arteries received both modalities (29 internal carotid arteries [ICAs] and 14 vertebral arteries [VAs]). All CADs were identified in CT/CTA and MRI/MRA. The features intimal flap, stenosis, and lumen irregularity appeared in both modalities. One high-grade stenosis was identified by CT/CTA that was expected occluded on MRI/MRA. Two MRI/MRA-confirmed pseudoaneurysms were missed by CT/CTA. None of the controls evidenced specific imaging signs for dissection., Conclusions: CT/CTA is a reliable and better available alternative to MRI/MRA for diagnosis of sCAD. CT/CTA should be used to complement MRI/MRA in cases where MRI/MRA suggests occlusion., (Copyright © 2017 by the American Society of Neuroimaging.)

Purpose: The purpose of this study is to determine the optimal target CT spatial resolution for accurately imaging abdominal aortic aneurysm (AAA) wall characteristics, distinguishing between tissue and calcification components, for an accurate assessment of rupture risk., Materials and Methods: Ruptured and non-ruptured AAA-wall samples were acquired from eight patients undergoing open surgical aneurysm repair upon institutional review board approval and informed consent was obtained from all patients. Physical measurements of AAA-wall cross-section were made using scanning electron microscopy. Samples were scanned using high resolution micro-CT scanning. A resolution range of 15.5-155μm was used to quantify the influence of decreasing resolution on wall area measurements, in terms of tissue and calcification. A statistical comparison between the reference resolution (15.5μm) and multi-detector CT resolution (744μm) was also made., Results: Electron microscopy examination of ruptured AAAs revealed extremely thin outer tissue structure <200μm in radial distribution which is supporting the aneurysm wall along with large areas of adjacent medial calcifications far greater in area than the tissue layer. The spatial resolution of 155μm is a significant predictor of the reference AAA-wall tissue and calcification area measurements (r=0.850; p<0.001; r=0.999; p<0.001 respectively). The tissue and calcification area at 155μm is correct within 8.8%±1.86 and 26.13%±9.40 respectively with sensitivity of 87.17% when compared to the reference., Conclusion: The inclusion of AAA-wall measurements, through the use of high resolution-CT will elucidate the variations in AAA-wall tissue and calcification distributions across the wall which may help to leverage an improved assessment of AAA rupture risk., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Objectives: This study analysed CT patterns of the acute dissected aortic arch using original biometric features along with comparison with normal aortas., Methods: The diagnostic CT scans of 57 patients (42 males, age (mean ± SD: 64.5 ± 13.8 years) admitted with acute Stanford type A dissection involving the aortic arch were analysed by semi-automatic detection protocol of the true lumen of the dissection. We measured the distances from the apex to the ascending and descending aorta, the curvilinear length of the entire arch and of its segments (especially between the brachiocephalic artery trunk and the left subclavian artery), as well as the surface area, angle, height and shift of the arch. These measurements were compared with results previously obtained in a healthy cohort in an analysis adjusted for age, sex and weight. The surface area and rotation of the false lumen were also analysed., Results: Compared to normal aortic arches (N), dissected aortic arches (D) were longer (D: 155 ± 26  mm, N: 135 ± 25  mm, p = 0.002), higher (D: 51 ± 10  mm, N: 45 ± 9  mm, p = 0.04), and with a more anterior apex (shift: D: 1.19 ± 0.56, N: 1.40 ± 0.62, p = 0.007). False lumen occupied between 47-65% of the aorta, turned preferentially clockwise and its rotation decreased progressively along the arch., Conclusions: The morphology of the dissected aortic arch differs from that of the normal arch. Thus, our compilation of aortic arch measurements may help improve existing endovascular devices and/or design of new endoprostheses. Advances in knowledge: In this article, we provide a comprehensive set of measurements of the dissected aortic arch, and show that dissected aortic arches are longer, higher, and with a more anterior apex than normal arches.

Background: We explored the value of cardiac computed tomography (CT) for the detection and prediction of mechanical complications related to the risk of sudden cardiac death (SCD) in pulmonary arterial hypertension (PAH) patients., Methods: PAH patients (n=60, mean age 47±15, 31.7% male) with pulmonary artery (PA) enlargement (≥40mm) by echocardiography were studied with cardiac CT. Complications explored were the presence of left main coronary artery (LM) compression, airway compression, PA dissection and PA thrombosis in relation to diameters of main PA (MPA) which were measured in (1) axial plane (MPA Ax ) and (2) LM oblique view (MPA LMobq )., Results: Mechanical complications were found in 21 patients (35.0%): LM compression in 20 patients; airway compression in 3 patients; and PA thrombosis in 4 patients. Patients with complications had more dilated MPA LMobq than patients without complication (59.4±13.0mm vs. 42.4±7.0mm, p<0.001). The area under the receiver operating characteristic curve for MPA LMobq was 0.889 (95% confidence interval: 0.795 to 0.983, p<0.001) with the highest discriminating sensitivity and specificity being 90.5% and 69.2%, respectively at MPA LMobq of 45mm. MPA Ax failed to predict the presence of mechanical complications (p>0.05)., Conclusion: MPA LMobq ≥45mm was significantly associated with the presence of mechanical complications of PAH. Evaluation with CT should be considered in PAH patients with dilated MPA., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Objective: The development of atherosclerotic plaques and spontaneous isolated dissection (SID) of the superior mesenteric artery (SMA) was considered to be related to opposite haemodynamics. The purpose of this study was to compare their occurrence sites and the morphology of the SMA to confirm the haemodynamic aetiologies., Methods: 57 patients with SID and 64 patients with atherosclerotic plaques were compared about patient characteristics, location of SID and plaque, the distance from lesion to the aortic ostia, SMA branching angle and inlet diameter of the SMA., Results: The location of SID and plaque was very different (p < 0.001). The anterior wall was the most common entry site of SIDSMA (84.0%) but the least frequent origin site of atherosclerotic plaques (7.8%). The posterior, left and right walls were the frequent origin sites of atherosclerotic plaques (total 92.2%) but not for SIDSMA. Most plaques started from the aortic ostia, and their average distance to the aortic ostia was significantly less than the distance from the entry site to the aortic ostia of SIDSMA (p < 0.001). No significant difference was found between SIDSMA and the plaque groups in the branching angle and inlet diameter of the SMA., Conclusion: The vastly different sites of SIDSMA and atherosclerotic plaque indicate their opposite haemodynamic aetiology. Advances in knowledge: By comparing the location of the two diseases, we demonstrate their different haemodynamic causes.

Background: This study compares the morphology and outcomes of acute retrograde type A dissections (RTADs) with acute antegrade type A dissections (ATADs), and acute type B dissections., Materials and Methods: From 2000 to 2016, there were 12 acute RTADs, 96 ATADs, and 92 type B dissections with available imaging. Dissections were characterized using computerized tomography angiography images. We examined clinical features, tear characteristics, and various morphologic measurements., Results: Compared with acute type B dissections, RTAD primary tears were more common in the distal arch (75% versus 43%, P = 0.04), and the false-to-true lumen contrast intensity ratio at the mid-descending thoracic aorta was lower (0.46 versus 0.71, P = 0.020). RTAD had less false lumen decompression because there were fewer aortic branch vessels distal to the subclavian that were perfused through the false lumen (0.40 versus 2.19, P < 0.001). Compared with ATAD, RTAD had less root involvement where root true-to-total lumen area ratio was higher (0.88 versus 0.76, P = 0.081). Furthermore, RTAD had a lower false-to-true lumen contrast intensity ratio at the root (0.25 versus 0.57, P < 0.05), ascending aorta (0.25 versus 0.72, P < 0.001), and proximal arch (0.39 versus 0.67, P < 0.05). RTAD were more likely to undergo aortic valve resuspension (100% versus 74%, P = 0.044)., Conclusions: RTAD tends to occur when primary tears occur in close proximity to the aortic arch and when false lumen decompression through the distal aortic branches are less effective. Compared with ATAD, RTAD has less root involvement, and successful aortic valve resuspension is more likely., (Published by Elsevier Inc.)

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.

Aim: To identify the predictive signs of aortic valve involvement on the non-electrocardiogram (ECG)-gated admission computed tomography (CT) of patients with Type A aortic dissection (AD) according to the Stanford classification., Materials and Methods: We retrospectively analyzed the non-ECG-gated CT examinations of patients admitted to the emergency department who underwent surgery for Type A AD over a period of 4 years. The diameter of the following structures was calculated as the mean of the smallest and largest diameters (mm) measured in two different planes: aortic annulus, sinus of Valsalva, sinotubular junction, and proximal ascending aorta. These parameters were compared against operative reports in order to determine whether they were predictive of aortic valve involvement., Results: In total, 20 patients (13 men and 7 women) of a mean age of 59.5 years (29-80) were included, 55% of patients (11/20) having surgically proven valvular involvement. The mean diameters (inmm) of the aortic annulus, sinus of Valsalva, sinotubular junction and proximal ascending aorta in the group with (and without, respectively) valvular involvement was 27.7 (26.7), 44.3 (38.1), 42.6 (36.6), and 47.8 (45.9). Only the measurement of the mean diameter of the sinuses of Valsalva was significantly predictive (p=0.02) of aortic valve involvement., Conclusion: Our findings suggest that measuring the diameter of the sinuses of Valsalva on non-ECG-gated admission CT examinations allows for predicting aortic valve involvement in Type A AD patients., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Aims: Conventional computed tomography (CT) approaches provides limited visualization of the entire endoluminal changes of aortic dissection (AD), which is essential for its treatment. As an important supplement, three-dimensional CT virtual intravascular endoscopy (VIE) can show relevant details. This study aims to determine the value of VIE in displaying the entry tear and intimal flap of AD., Methods and Results: Among 127 consecutive symptomatic patients with suspected AD who underwent CT angiography (CTA), 84 subjects were confirmed to have AD and were included in the study. Conventional CT and VIE images were observed and evaluated. From the 92 entry tears revealed via conventional CT, 88 (95.7%) tears appeared on VIE with round (n = 26), slit-shaped (n = 9), or irregular (n = 53) shapes, whereas the intimal flaps were sheetlike (n = 34), tubular (n = 34), wavelike (n = 13), or irregular (n = 7) in shape. The VIE also showed the spatial relationship between the torn flap and adjacent structures. Among 58 entry tears with multiple-line type flap shown on conventional CT, 41 (70.7%) appeared with an irregular shape on VIE, whereas among 30 tears with single-line type flap, 17 (56.7%) appeared as round or slit-shaped on VIE. These results demonstrated a significant difference (P < 0.05). The poor display of tears on VIE was related to the low CT attenuation values in lumen or in neighboring artifacts (P < 0.01)., Conclusion: CT VIE presents the complete configurations and details of the intimal tears and flaps of AD better than conventional CT approaches. Accordingly, it should be recommended as a necessary assessment tool for endovascular therapy and as part of strategy planning in pre-surgical patients., Competing Interests: The authors have declared that no competing interests exist.

Background: Spontaneous isolated superior mesenteric artery (SMA) dissection is a rare condition, and its clinical and angiographic courses are poorly defined. We aimed to monitor the morphological characteristics of spontaneous isolated SMA dissection using computed tomography (CT) over 2 years of follow-up, including the recovery process via vascular remodeling, and identify the factors that affect vascular remodeling using univariate analysis., Methods and results: We retrospectively reviewed the medical records and morphological findings of 59 consecutive patients with spontaneous isolated SMA dissection between October 2007 and July 2014, which included 36 symptomatic and 23 asymptomatic patients. Surgical intervention with open laparotomy was required in 3 patients during the follow-up period; 41 patients who received conservative treatment were followed up over 2 years with regular CT. Complete remodeling was achieved in 16 of 25 symptomatic patients who were treated conservatively (64.0%). A patent false lumen and aneurysmal formation on an initial CT scan were identified as negative factors that affected remodeling in patients with spontaneous isolated SMA dissection., Conclusions: Conservative management of spontaneous isolated SMA dissection is associated with a good prognosis, both clinically and morphologically. Surgical intervention is only required in patients with severe intestinal ischemia or rapid aneurysmal enlargement. (Circ J 2016; 80: 1452-1459).

Objectives: This study sought to evaluate variability in aortic measurements with multiple imaging modalities in clinical centers by comparing with a standardized measuring protocol implemented in a core laboratory., Background: In patients with aortic disease, imaging of thoracic aorta plays a major role in risk stratifying individuals for life-threatening complications and in determining timing of surgical intervention. However, standardization of the procedures for performance of aortic measurements is lacking., Methods: To characterize the diversity of methods used in clinical practice, we compared aortic measurements performed by echocardiography, computed tomography (CT), and magnetic resonance imaging (MRI) at the 6 GenTAC (National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions) clinical centers to those performed at the imaging core laboratory in 965 studies. Each center acquired and analyzed their images according to local protocols. The same images were subsequently analyzed blindly by the core laboratory, on the basis of a standardized protocol for all imaging modalities. Paired measurements from clinical centers and core laboratory were compared by mean of differences and intraclass correlation coefficient (ICC)., Results: For all segments of the ascending aorta, echocardiography showed a higher ICC (0.84 to 0.93) than CT (0.84) and MRI (0.82 to 0.90), with smaller mean of differences. MRI showed higher ICC for the arch and descending aorta (0.91 and 0.93). In a mixed adjusted model, the different imaging modalities and clinical centers were identified as sources of variability between clinical and core laboratory measurements, whereas age groups or diagnosis at enrollment were not., Conclusions: By comparing core laboratory with measurements from clinical centers, our study identified important sources of variability in aortic measurements. Furthermore, our findings with regard to CT and MRI suggest a need for imaging societies to work toward the development of unifying acquisition protocols and common measuring methods., (Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Accurate and timely assessment of suspected acute aortic syndrome is crucial in this life-threatening condition. Imaging with CT plays a central role in the diagnosis to allow expedited management. Diagnosis can be made using locally available expertise with optimized scanning parameters, making full use of recent advances in CT technology. Each imaging centre must optimize their protocols to allow accurate diagnosis, to optimize radiation dose and in particular to reduce the risk of false-positive diagnosis that may simulate disease. This document outlines the principles for the acquisition of motion-free imaging of the aorta in this context.

Thoracic endovascular aortic repair (TEVAR) has become an accepted alternative to surgery for the treatment of aortic dissection (AD). Lifelong surveillance is obligatory following TEVAR to monitor the aortic morphology and detect associated complications. This is particularly important in AD where coverage of the primary intimal tear is necessary in achieving thrombosis and regression of the false lumen. A variety of imaging techniques may be used in assessing the technical success, outcome and complications, which may necessitate re-intervention. Of these, computed tomography angiography offers a fast, accessible and sensitive imaging modality and is established as the default surveillance tool. The purpose of this article is to review the imaging modalities, post-procedural appearances including complications and re-intervention strategies following TEVAR for AD.

Objectives: To assess aortic arch morphology and aortic length in patients with dissection, traumatic injury, and aneurysm undergoing TEVAR, and to identify characteristics specific to different pathologies., Method: This was a retrospective analysis of the aortic arch morphology and aortic length of dissection, traumatic injury, and aneurysmal patients. Computed tomography imaging was evaluated of 210 patients (49 dissection, 99 traumatic injury, 62 aneurysm) enrolled in three trials that received the conformable GORE TAG thoracic endoprosthesis. The mean age of trauma patients was 43 ± 19.6 years, 57 ± 11.7 years for dissection and 72 ± 9.6 years for aneurysm patients. A standardized protocol was used to measure aortic arch diameter, length, and take-off angle and clockface orientation of branch vessels. Differences in arch anatomy and length were assessed using ANOVA and independent t tests., Results: Of the 210 arches evaluated, 22% had arch vessel common trunk configurations. The aortic diameter and the distance from the left main coronary (LMC) to the left common carotid (LCC) were greater in dissection patients than in trauma or aneurysm patients (p < .001). Aortic diameter in aneurysm patients was greater compared with trauma patients (p < .05). The distances from the branch vessels to the celiac artery (CA) were greater in dissection and aneurysm patients than in trauma patients (p < .001). The take-off angle of the innominate (I), LCCA, and left subclavian (LS) were greater, between 19% and 36%, in trauma patients than in dissection and aneurysm patients (p < .001). Clockface orientation of the arch vessels varies between pathologies., Conclusions: Arch anatomy has significant morphologic differences when comparing aortic pathologies. Describing these differences in a large sample of patients is beneficial for device designs and patient selection., (Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.)

Objectives: Acute type A aortic dissection (TAAD) is a life-threatening emergency and requires immediate surgical intervention. We propose a novel finite element multi-dimensional modelling (FE-MDM) technique to identify aortic tears preoperatively to aid surgical preplanning., Methods: Thirty-two patients with TAAD were included in this retrospective study. Computed tomography (CT) scans were imported using the segmentation software and reconstruction resulted in modelling of single TAAD components: aortic wall, false lumen, true lumen, gap in the flap and blood in both lumens. CT scans were processed by interpreters who were blinded to the clinical data and then were compared with operative findings. The models were assessed and compared regarding localization and size of the entry tear with the intraoperative findings. Image set data were retrieved from CT scans., Results: Surgical inspection confirmed the localization of the tear obtained by the model in all patients with a 100% chance prediction (P < 0.0001) in all patients. With the simulation of the guided-cannulation, it was possible to place the cannula in the ascending aorta in 100% of patients (P < 0.0001 vs surgery). Using the virtual volume model, the chance of inserting into the false lumen was 0% (P < 0.0001). There was a strong correlation between the virtual volume model and cannulation in the true lumen (r = 0.88, P < 0.0001)., Conclusions: The FE-MDM technique of aortic dissection is helpful in identifying the site of the tear and may be considered as an additional tool in surgical preplanning. It may also enhance the efficiency of deep hypothermic circulatory arrest in patients with single entry sites in the ascending aorta and it may facilitate direct cannulation of the ascending aorta., (© The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)