Mixed reality for the assessment of aortoiliac anatomy in patients with abdominal aortic aneurysm prior to open and endovascular repair: Feasibility and interobserver agreement

Objectives The objective is to evaluate the feasibility and interobserver agreement of a Mixed Reality Viewer (MRV) in the assessment of aortoiliac vascular anatomy of abdominal aortic aneurysm (AAA) patients. Methods Fifty preoperative computed tomography angiographies (CTAs) of AAA patients were included. CTAs were assessed in a mixed reality (MR) environment with respect to aortoiliac anatomy according to a standardized protocol by two experienced observers (Mixed Reality Viewer, MRV, Brainlab AG, Germany). Additionally, all CTAs were independently assessed applying the same protocol by the same observers using a conventional DICOM viewer on a two-dimensional screen with multi-planar reconstructions (Conventional viewer, CV, GE Centricity PACS RA1000 Workstation, GE, United States). The protocol included four sets of items: calcification, dilatation, patency, and tortuosity as well as the number of lumbar and renal arteries. Interobserver agreement (IA, Cohen’s Kappa, κ) was calculated for every item set. Results All CTAs could successfully be displayed in the MRV (100%). The MRV demonstrated equal or better IA in the assessment of anterior and posterior calcification (κMRV: 0.68 and 0.61, κCV: 0.33 and 0.45, respectively) as well as tortuosity (κMRV: 0.60, κCV: 0.48) and dilatation (κMRV: 0.68, κCV: 0.67). The CV demonstrated better IA in the assessment of patency (κMRV: 0.74, κCV: 0.93). The CV also identified significantly more lumbar arteries (CV: 379, MRV: 239, p < 0.01). Conclusions The MRV is a feasible imaging viewing technology in clinical routine. Future efforts should aim at improving hologram quality and enabling accurate registration of the hologram with the physical patient

ECG-triggered non-enhanced MR angiography of peripheral arteries in comparison to DSA in patients with peripheral artery occlusive disease

Object: The purpose of this study was to evaluate peripheral non-enhanced-MRA (NE-MRA) acquired with a 3D Turbo Spin Echo sequence with electrocardiographt (ECG) triggering in comparison to Digital Subtraction Angiography (DSA) as the gold standard in symptomatic peripheral artery occlusive disease (PAOD) patients. Materials and methods: This IRB approved prospective study included 23 PAOD patients from whom three patients had to be excluded. The remaining 20 subjects were included in the analysis (15 male; mean age 62.4±15.3years). The patients first underwent DSA followed by NE-MRA on a 1.5-T whole body scanner within 24h after the DSA study. A NATIVE (Non-contrast Angiography of the Arteries and Veins) SPACE (Sampling Perfection with Application Optimized Contrast by using different flip angle Evolution) sequence at four levels (pelvis, upper leg, knee region and lower leg) was acquired. For evaluation purposes, subtracted standardized MIP (maximum intensity projection) images were generated from the NE-MRA data sets. Qualitative assessment of NE-MRA images in reference to the corresponding DSA images, as well as blinded stenosis grading of preselected segments in NE-MRA images were performed by two experienced readers. Image quality in 95 corresponding arterial segments was rated from 1 (good) to 4 (inadequate) directly comparing the NE-MRA with the corresponding DSA segment as the gold standard. Blinded stenosis grading consisted of 66 preselected stenoses rated from 1 (90%) in NE-MRA which were compared to the grade in the corresponding DSA. Results: The mean image quality of NE-MRA in comparison to DSA was 2.7±1.1 (reader 1) and 3.0±1.0 (reader 2). The kappa value indicating interobserver agreement was 0.34; readers 1 and 2 rated the image quality as good in 21% and 3%, sufficient in 19% and 41%, limited in 29% and 14% and inadequate in 31% and 42%, respectively. Stenosis graduation revealed significantly higher grades in NE-MRA (reader 1: 3.0±0.7, p<0.001 and reader 2: 3.1+0.8, p<0.001) compared to DSA (mean value DSA 2.7±0.8). The kappa value indicating interobserver agreement concerning stenosis grading was 0.59. Conclusion: NE-MRA revealed a relatively high number of inadequate quality segments. This is in line with recently published comparable studies of the similar SPACE NE-MRA techniques. Further advance of NE-MRA techniques remains desirable for patients with PAO

Outcome analysis and risk factors for postoperative colonic ischaemia after aortic surgery

Purpose!#!Colonic ischaemia (CI) represents a serious complication after aortic surgery. This study aimed to analyse risk factors and outcome of patients suffering from postoperative CI.!##!Methods!#!Data of 1404 patients who underwent aortic surgery were retrospectively analysed regarding CI occurrence. Co-morbidities, procedural parameters, colon blood supply, procedure-related morbidity and mortality as well as survival during follow-up (FU) were compared with patients without CI using matched-pair analysis (1:3).!##!Results!#!Thirty-five patients (2.4%) with CI were identified. Cardiovascular, pulmonary and renal comorbidity were more common in CI patients. Operation time was longer (283 ± 22 vs. 188 ± 7 min, p &amp;lt; 0.0001) and blood loss was higher (2174 ± 396 vs. 1319 ± 108 ml, p = 0.0049) in the CI group. Patients with ruptured abdominal aortic aneurysm (AAA) showed a higher rate of CI compared to patients with intact AAA (5.4 vs. 1.9%, p = 0.0177). CI was predominantly diagnosed by endoscopy (26/35), generally within the first 4 postoperative days (20/35). Twenty-eight patients underwent surgery, all finalised with stoma creation. Postoperative bilateral occlusion and/or relevant stenosis of hypogastric arteries were more frequent in CI patients (57.8 vs. 20.8%, p = 0.0273). In-hospital mortality was increased in the CI group (26.7 vs. 2.9%, p &amp;lt; 0.0001). Survival was significantly reduced in CI patients (median: 28.2 months vs. 104.1 months, p &amp;lt; 0.0001).!##!Conclusion!#!CI after aortic surgery is associated with considerable perioperative sequelae and reduced survival. Especially in patients at risk, such as those with rAAA, complicated intraoperative course, severe cardiovascular morbidity and/or perioperative deterioration of the hypogastric perfusion, vigilant postoperative multimodal monitoring is required in order to initiate diagnosis and treatment

Prevalence of the Computed Tomographic Morphological DISSECT Predictors in Uncomplicated Stanford Type B Aortic Dissection

Objective/Background: The aim was to analyse the prevalence of computed tomographic (CT) morphological predictors and their influence on early chronic phase aortic diameter expansion in patients with uncomplicated acute Stanford type B aortic dissection (ATBAD). Methods: This retrospective analysis reviewed the CT imaging of 140 patients admitted with uncomplicated ATBAD to two tertiary centres between March 2003 and April 2016. The prevalence of the following CT-morphological predictors was determined at baseline: primary entry tear (PET) diameter >= 10 mm, its location at the concavity of the aortic arch; maximum descending aortic diameter >= 40 mm; false lumen (FL) diameter >= 22 mm; partial FL thrombosis and a fusiform index (FI) of >= 0.64. Thoracic aortic diameter expansion (ADE) was evaluated in 65 patients treated by best medical therapy (BMT) (median CT follow up 11.6 months). Study end points were predictor prevalence and ADE. Results: A mean +/- SD of 2.45 +/- 1.35 predictors were registered among all 140 patients; 75.0% of patients showed at least two predictors. In 7.9% of patients, no predictor was found. The prevalence of PET at the arch concavity was 18.6%, PET diameter >= 10 mm in 60.0%, maximal descending aortic diameter >= 40 mm in 51.4%, FL diameter >= 22 mm in 47.9%, partial FL thrombosis in 47.9%, and FI >= 0.64 in 20.7%. An ADE >= 5 mm was observed in 38 of 65 patients. Median observed ADE was 5.1 mm (median follow up (FU) 11.6 months, range -3.2-27.4 mm). Regression analysis for multiple predictors showed a basic ADE of 2.5 mm plus 1.9 mm per predictor at the median FU of 11.6 months (2.5 mm +/- 1.9; 95% confidence interval CI = 0.2-5.2 mm +/- 0.7-3.0 mm; p=.003). Conclusion: In the majority of patients, at least one of the investigated morphological predictors of disease progression in uncomplicated ATBAD was detected. An ADE >= 5 mm affected 38 of 65 BMT patients. CT based predictors help to define TBAD patients at risk of progression. (C) 2018 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved

Automated 3D Volumetry of the Pulmonary Arteries based on Magnetic Resonance Angiography Has Potential for Predicting Pulmonary Hypertension

Purpose To demonstrate feasibility of automated 3D volumetry of central pulmonary arteries based on magnetic resonance angiography (MRA), to assess pulmonary artery volumes in patients with pulmonary hypertension compared to healthy controls, and to investigate the potential of the technique for predicting pulmonary hypertension. Methods MRA of pulmonary arteries was acquired at 1.5T in 20 patients with pulmonary arterial hypertension and 21 healthy normotensive controls. 3D model-based image analysis software was used for automated segmentation of main, right and left pulmonary arteries (MPA, RPA and LPA). Volumes indexed to vessel length and mean, minimum and maximum diameters along the entire vessel course were assessed and corrected for body surface area (BSA). For comparison, diameters were also manually measured on axial reconstructions and double oblique multiplanar reformations. Analyses were performed by two cardiovascular radiologists, and by one radiologist again after 6 months. Results Mean volumes of MPA, RPA and LPA for patients/controls were 5508 +/- 1236/3438 +/- 749, 3522 +/- 934/1664 +/- 468 and 3093 +/- 692/1812 +/- 474 mu l/(cm length x m(2) BSA) (all p<0.001). Mean, minimum and maximum diameters along the entire vessel course were also significantly increased in patients compared to controls (all p<0.001). Intra-and interobserver agreement were excellent for both volume and diameter measurements using 3D segmentation (intraclass correlation coefficients 0.971-0.999, p<0.001). Area under the curve for predicting pulmonary hypertension using volume was 0.998 (95% confidence interval 0.990-1.0, p<0.001), compared to 0.967 using manually measured MPA diameter (95% confidence interval 0.910-1.0, p<0.001). Conclusions Automated MRA-based 3D volumetry of central pulmonary arteries is feasible and demonstrated significantly increased volumes and diameters in patients with pulmonary arterial hypertension compared to healthy controls. Pulmonary artery volume may serve as a superior predictor for pulmonary hypertension compared to manual measurements on axial images but verification in a larger study population is warranted

Prospective Study of Low-Radiation and Low-Iodine Dose Aortic CT Angiography in Obese and Non-Obese Patients: Image Quality and Impact of Patient Characteristics

The purpose of this study was to prospectively analyse image quality and radiation dose of body mass index (BMI)-adapted low-radiation and low-iodine dose CTA of the thoracoabdominal aorta in obese and non-obese patients. This prospective, single-centre study included patients scheduled for aortic CTA between November 2017 and August 2020 without symptoms of high-grade heart failure. A BMI-adapted protocol was used: Group A/Group B, BMI 2, tube potential 80/100 kVp, total iodine dose 14.5/17.4 g. Intraindividual comparison with the institutional clinical routine aortic CTA protocol was performed. The final study cohort comprised 161 patients (mean 71.1 ± 9.4 years, 32 women), thereof 126 patients in Group A (mean BMI 25.4 ± 2.8 kg/m2) and 35 patients in Group B (34.0 ± 3.4 kg/m2). Mean attenuation over five aortoiliac measurement positions for Group A/B was 354.9 ± 78.2/262.1 ± 73.0 HU. Mean effective dose for Group A/B was 3.05 ± 0.46/6.02 ± 1.14 mSv. Intraindividual comparison in 50 patients demonstrated effective dose savings for Group A/B of 34.4 ± 14.5/25.4 ± 14.1% (both p < 0.001), and iodine dose savings for Group A/B of 54/44.8%. Regression analysis showed that female sex and increasing age were independently associated with higher vascular attenuation. In conclusion, BMI-adapted, low-radiation and low-iodine dose CTA of the thoracoabdominal aorta delivers diagnostic image quality in non-obese and obese patients without symptoms of high-grade heart failure, with superior image quality in females and the elderly

Association of Tumor Volumetry with Postoperative Outcomes for Cervical Paraganglioma

Objectives: To analyze the association of tumor volume with outcome after surgery for cervical paraganglioma. Materials and Methods: This retrospective study included consecutive patients undergoing surgery for cervical paraganglioma from 2009–2020. Outcomes were 30-day morbidity, mortality, cranial nerve injury, and stroke. Preoperative CT/MRI was used for tumor volumetry. An association between the volume and the outcomes was explored in univariate and multivariable analyses. A receiver operating characteristic (ROC) curve was plotted, and the area under the curve (AUC) was calculated. The study was conducted and reported according to the STROBE statement. Results: Volumetry was successful in 37/47 (78.8%) of included patients. A 30-day morbidity occurred in 13/47 (27.6%) patients with no mortality. Fifteen cranial nerve lesions occurred in eleven patients. The mean tumor volume was 6.92 cm3 in patients without and 15.89 cm3 in patients with complications (p = 0.035) and 7.64 cm3 in patients without and 16.28 cm3 in patients with cranial nerve injury (p = 0.05). Neither the volume nor Shamblin grade was significantly associated with complications on multivariable analysis. The AUC was 0.691, indicating a poor to fair performance of volumetry in predicting postoperative complications. Conclusions: Surgery for cervical paraganglioma bears a relevant morbidity with a particular risk of cranial nerve lesions. Tumor volume is associated with morbidity, and MRI/CT volumetry can be used for risk stratification