Computed Tomography Angiography Scans Research Articles

External Validation of Fully-Automated Infrarenal Maximum Aortic Aneurysm Diameter Measurements in Computed Tomography Angiography Scans Using Artificial Intelligence (PRAEVAorta 2)

Purpose: This study investigates the accuracy of fully-automated maximum aortic diameter measurements in abdominal aortic aneurysm (AAA) patients using artificial intelligence software (PRAEVAorta 2, Nurea, Bordeaux, France). Materials and Methods: This is a multicenter, retrospective validation study using prospectively collected data from the Zenith alpha for aneurysm Repair Registry (ZEPHYR). Automated measurements of PRAEVAorta 2 are compared with measurements of an internationally recognized core laboratory (Syntactx, New York, New York State). The reviewers at the core laboratory were measurement technologists trained to and utilizing established measurement standards, overseen by vascular surgeons and radiologists. The data set comprised 871 computed tomography angiography scans from the ZEPHYR registry with 347 patients who underwent endovascular aneurysm repair (EVAR) with the Zenith Alpha Endovascular Abdominal Graft (Cook Medical, Bloomington, Indiana) in Germany, Belgium, and The Netherlands between 2016 and 2019. Results: The analysis demonstrated excellent correlation of the measurements (r=0.97) with an intraclass correlation (ICC) of 0.972 (95% confidence interval [CI]=0.968-0.976) across all scans. For preoperative computed tomography (CT) scans, ICC was 0.953 (95% CI=0.941-0.963), and for postoperative scans, ICC was 0.979 (95% CI=0.975-0,983), respectively. In total, 95.4% of measurements were within the clinically acceptable range of 5 mm in absolute difference. In total, 10% of scans demonstrated obvious segmentation errors, mainly due to failure in detecting vessel segments (renal arteries, aortic bifurcation) or due to mis-detecting the outer border of the AAA (duodenum, inferior vena cava, aortic branches) and were excluded from the analysis. Conclusion: In this study, the maximum AAA diameter could be accurately measured fully-automatically by PRAEVAorta 2 (Nurea) in most cases demonstrating that artificial intelligence (AI) software could serve as an important adjunct for research and clinical practice. However, critical review of the generated reports by an experienced observer and cautious use is warranted to identify flawed segmentations. Clinical Impact This multicenter, retrospective validation study assessed the accuracy of fully-automated maximum infrarenal aortic aneurysm diameter measurements. It was demonstrated, that 95.4% of measurements were within the clinically acceptable range of 5 mm in absolute difference, positioning the software as a potential adjunct for clinical practice and research. It is also highlighted however, that critical review of the measurements is obligatory, due to a 10% segmentation error rate.

Enhanced Preoperative Planning for Intracranial Aneurysms Through Multimodal Image Fusion of Silent/Time-of-Magnetic Resonance Angiography and Computed Tomography Using 3DSlicer: A Comparative Efficacy Analysis With Computed Tomography Angiography.

This study evaluates the effectiveness of multimodal image fusion (MIF) using silent and time-of-flight (TOF) magnetic resonance angiography (MRA) and computed tomography (CT) for preoperative planning in patients with intracranial aneurysms who have contraindications to contrast media. A retrospective study included 40 patients with intracranial aneurysms, diagnosed using three-dimensional computed tomography angiography (CTA). These patients underwent both Silent and TOF MRA scans, followed by a CTA scan. The multi-image fusion (MIF) technique, applied using 3DSlicer software, integrated the silent/TOF-MRA with CT images for preoperative assessment. This study compared the image quality, aneurysm detection sensitivity, and anatomic accuracy of the MIF images with those of three-dimensional CTA. Silent-MRA-CT fusion images demonstrated higher sensitivity (95.5%) and lower false negative rates (4.5%) compared with TOF-MRA-CT. Furthermore, silent-MRA-CT fusion images outperformed TOF-MRA-CT in terms of signal homogeneity, venous signal interference suppression, and aneurysm visibility (all P < 0.05). The interclass correlation coefficient and kappa values for aneurysm morphology and shape indicated superior measurement consistency and shape concordance of silent-MRA-CT with CTA compared with TOF-MRA-CT (all P < 0.01). This study supports the use of silent/TOF-MRA-CT fusion imaging as a reliable alternative to CTA, noting that silent-MRA-CT closely mirrors CTA. Contrast-free MRA-CT fusion images have the potential to be used for preoperative planning in patients with intracranial aneurysms who have contraindications to contrast.

Characterizing Nonculprit Lesions and Perivascular Adipose Tissue of Patients Following Acute Myocardial Infarction Using Coronary Computed Tomography Angiography: A Comparative Study.

The comparison of coronary computed tomography angiography plaques and perivascular adipose tissue (PVAT) between patients with acute myocardial infarction (AMI) posttreatment and patients with stable coronary artery disease is poorly understood. Our objective was to evaluate the differences in coronary computed tomography angiography-quantified plaque and PVAT characteristics in patients post-AMI and identify signs of residual inflammation. We analyzed 205 patients (age, 59.77±9.24 years; 92.20% men) with AMI ≤1 month and matched them with 205 patients with stable coronary artery disease (age, 60.52±10.04 years; 90.24% men) based on age, sex, and cardiovascular risk factors. Coronary computed tomography angiography scans were assessed for nonculprit plaque and vessel characteristics, plaque volumes by composition, high-risk plaques, and PVAT mean attenuation. Both patient groups exhibited similar noncalcified plaque volumes (383.35±313.23 versus 378.63±426.25 mm3, P=0.899). However, multivariable analysis revealed that patients post-AMI had a greater patient-wise noncalcified plaque volume ratio (estimate, 0.089 [95% CI, 0.053-0.125], P<0.001), largely attributed to a higher fibrofatty and necrotic core volume ratio, along with higher peri-lesion PVAT mean attenuation (estimate, 3.968 [95% CI, 2.556-5.379], P<0.001). When adjusted for vessel length, patients post-AMI had more high-risk plaques (estimate, 0.417 [95% CI, 0.298-0.536], P<0.001) per patient. Patients post-AMI displayed heightened noncalcified plaque components, largely due to fibrofatty and necrotic core content, more high-risk plaques, and increased PVAT mean attenuation on a per-patient level, highlighting the necessity for refined risk assessment in patients with AMI after treatment.

AI-enabled cardiac chambers volumetry in non-contrast coronary artery calcium CT scans vs. contrast-enhanced coronary CT angiography scans in the same patients

Abstract Introduction We have developed an AI-enabled automated volumetry of cardiac chambers (AutoChamber) that works both on non-contrast ECG-gated cardiac CT scans used for coronary artery calcium (CAC) score, and non-contrast non-gated lung cancer screening CT scans. We have recently reported the agreement between AutoChamber measurements vs cardiac MRI measurements. Here we report AutoChamber results on non-contrast CAC scans and contrast enhanced coronary CT angiography (CTA). Methods We have obtained CT images from a previously published study in which 131 cases underwent non-contrast CAC and contrast enhanced CCTA at research institute. The cases consisted of 52.4% women with ages 55.0 ± 10.1 years. The cardiac chambers volume in 131 cases of contrast enhanced CCTA were measured using automated chamber volumetry by Philips Brilliance Volume v 4.5; Philips Healthcare. Results The correlations between Philips’ automated chamber volumetry in contrast enhanced CCTA scans versus AutoChamber automated volumetry in non-contrast CAC scans for left atrium (LA), left ventricle (LV), right atrium (RA), right ventricle (RV), and left ventricular wall (LVW) volume were 0.73, 0.65, 0.85, 0.93, 0.90, respectively (P for all &amp;lt;0.01). Conclusion AI-enabled AutoChamber volumetry based on non-contrast cardiac scans is feasible, and correlates reasonably well with contrast-enhanced cardiac CT scans. Further studies are warranted to reproduce these results and explore the add-on value of AutoChamber to CAC scans.

AI-enabled automated cardiac chambers volumetry in non-contrast ECG-gated cardiac scans vs. non-contrast non-gated lung scans

Abstract Introduction We have developed an AI-enabled automated volume measurement of cardiac chambers (AutoChamber) that works on ECG-gated coronary artery calcium scans and correlates well with contrast enhanced coronary CT angiography scans. We have recently reported that increased left atrial volume measured by AutoChamber is a strong predictor of new onset atrial fibrillation (AF) in asymptomatic individuals of Multi-Ethnic Study of Atherosclerosis (MESA). In this study, we compare the volumetry results in ECG- gated CAC scans with those of non-gated full-chest lung cancer screening scans in the same individuals. Methods We have studied 169 cases of paired ECG-gated cardiac CT scans and non-gated lung scans obtained from Harbor UCLA. Mean±SD for age was 62.1±10.0 years with 52% female participants. All cases were asymptomatic and were scanned for preventive health assessment. AutoChamber was run on all cases by an independent operator who was not involved in data analysis. P value was calculated using a two-tailed test of significance with α=0.05. Results AutoChamber in cardiac scans vs lung scans reported volume (Mean±SD) for left atrium (LA) was 63.8 ± 18.5 vs. 65.5 ± 19.4, left ventricle (LV) 102.8 ± 25.3 vs. 105.5 ± 25.2, right atrium (RA) 81.9 ± 20.5 vs. 85.7 ± 21.9 right ventricle (RV), 140.7 ± 34.2 vs. 134.2 ± 33.7, left ventricle wall (LVW) 113.0 ± 26.6 vs. 109.7 ± 27.0 respectively (P &amp;lt; 0.0001). Strong correlation was shown between cardiac and lung scans for each cardiac chamber: LA (R = 0.92), LV (R = 0.93), RA (R = 0.91), RV (R = 0.92), and left ventricular wall (LVW) R = 0.95. Conclusions AutoChamber volumetry results are similar in ECG-gated cardiac scans vs non-gated full-chest lung scans. This AI-enabled automated tool is promising as it can provide added value to patients undergoing coronary calcium and lung cancer screening scans flagging enlarged cardiac chambers at risk of AF and heart failure.

Growth Rate Assessed by Vascular Deformation Mapping predicts Type B Aortic Dissection in Marfan Syndrome.

Patients with Marfan syndrome (MFS) are at a high risk of type B dissection (TBAD). Aortic growth and elongation have been suggested as risk factors for TBAD. Vascular deformation mapping (VDM) is an image analysis technique for mapping 3D aortic growth on rouine computed tomography angiography (CTA) scans. We aimed to use VDM to examine the value of aortic growth rate in the descending thoracic aorta (DescAo), among other imaging biomarkers, to identify the factors associated with risk of TBAD in MFS. CTA scans spanning 2004-2023 from adult MFS patients with native DescAo were analyzed by VDM. Other measurements included multi-level thoracoabdominal aortic diameters and the length of the DescAo by centerline analysis. Among the 105 MFS patients analyzed, 63.8% were male, with median age of 40 years (range 18-73) and a median surveillance interval of 5.3 years (range 2.0-18.3). During surveillance, 12 (11.4%) patients developed TBAD. Patients with TBAD had higher radial growth rate (0.63 vs. 0.23 mm/year; p < 0.001) and elongation rate (2.4 vs. 0.5 mm/year; p < 0.001), on univariate and multivariable analysis, but pre-dissection descending aortic diameter was not significantly different. Predictors of growth rate included younger age, higher baseline maximal diameter of the DescAo, smoking history and warfarin use. Radial growth and elongation rates of the DescAo were independent predictors of TBAD occurrence in MFS. TBAD often occurred in at non-aneurysmal diameters. These findings emphasize the role of growth over absolute diameter in risk stratification for TBAD in MFS.

Poor venous outflow is associated with hyperintense acute reperfusion marker on follow-up MRI in patients with acute ischemic stroke with a large vessel occlusion

BackgroundHyperintense acute reperfusion marker (HARM) refers to delayed enhancement in the subarachnoid or subpial space on post-contrast fluid attenuated inversion recovery (FLAIR) images. HARM is a measure of blood–brain barrier...

Sex estimation by morphometric analysis of the intracranial volume and foramen magnum on three-dimensional volume rendering computed tomography

Purpose: Identification of decomposed human bodies and bone remains is very important in medicolegal examinations. The cranium has an important place in sex estimation due to its dimorphic features. Recent studies in this field have used radiological methods. The present study aimed to examine sexual dimorphism through morphometric analysis of the intracranial volume and Foramen Magnum on Three-Dimensional (3D) Volume Rendering Computed Tomography (CT) images. Methods: For this purpose, 3D images were generated after the reconstruction of CT Angiography scans of 87 female and 107 male cases. The length, width, circumference, area, and intracranial volume of the foramen magnum were measured on these 3D images. Results: All measurements except foramen magnum index were greater in males than in females (p

CT imaging using variable helical pitch scanning for lower extremity arterial disease: Reduced contrast medium dose, improved image quality and diagnostic accuracy

ObjectivesThis study aimed to explore the feasibility of reducing contrast medium (CM) volume, improving image quality and diagnostic accuracy using variable helical pitch (VHP) scanning for patients with lower extremity arterial disease (LEAD). Materials and MethodsEighty patients who underwent lower extremity CT angiography (CTA) were prospectively enrolled and randomly assigned to either the VHP group (n = 40) or the conventional group (n = 40). Quantitative parameters and qualitative scores were compared between the two groups. Additionally, out of these patients, 72 arteries from 18 patients had DSA as the reference standard, and the diagnostic accuracy for the degree of vessel stenosis was assessed and compared. ResultsIn the VHP group, the contrast volume was significantly lower than in the conventional group (79.55 ± 11.87 mL vs. 89.63 ± 10.03 mL, p < 0.001), showing a reduction of 12.7 %. For all image quality characteristics, scores in VHP group were significantly superior to those in the conventional groups (all p < 0.05). Quantitative analysis revealed that images from the VHP group exhibited superior CT enhancement, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) in the anterior tibial arteries (ATA) and dorsali pedis arteries (DPA) compared to the conventional group (all p < 0.001). Moreover, segment-based analysis showed the VHP group had significantly higher positive predictive value (PPV) and accuracy than the conventional group (PPV: 100 % vs. 76.19 %, p = 0.01; accuracy: 100 % vs. 84.38 %, p = 0.01, respectively). ConclusionsThe implementation of the VHP protocol led to a 12.7% decrease in contrast medium dosage compared to the conventional lower extremity CTA scanning protocol. Furthermore, it improved image quality and diagnostic accuracy, particularly for arteries below the knee.

Measurement of transcranial Doppler insonation angles from three-dimensional reconstructions of CT angiography scans.

Blood velocities measured by Transcranial Doppler (TCD) are dependent on the angle between the incident ultrasound beam and the direction of blood flow (known as the Doppler angle). However, when TCD examinations are performed without imaging the Doppler angle for each vessel segment is not known. We have measured Doppler angles in the basal cerebral arteries examined with TCD using three-dimensional (3D) vessel models generated from computed tomography angiography (CTA) scans. This approach produces angle statistics that are not accessible during non-imaging TCD studies. We created 3D models of the basal cerebral arteries for 24 vasospasm patients. Standard acoustic windows were mapped to the specific anatomy of each patient. Virtual ultrasound transmit beams were generated that originated from the acoustic window and intersected the centerline of each arterial segment. Doppler angle measurements were calculated and compiled for each vessel segment. Doppler angles were smallest for the middle cerebral artery M1 segment (median 24.6°) and ophthalmic artery (median 25.0°), and largest for the anterior cerebral artery A2 segment (median 76.4°) and posterior cerebral artery P2 segment (median 75.8°). The ophthalmic artery had the highest proportion of Doppler angles that were less than 60° (99%) while the anterior cerebral artery A2 segment had the lowest proportion of Doppler angles that were less than 60° (10%). These angle measurements indicate the expected deviation between measured and true velocities in the cerebral arteries, highlighting specific segments that may be prone to underestimation of velocity.

3D-targeted, electrocardiographic imaging-aided stereotactic radioablation for ventricular tachycardia storm: a case report

Abstract Background Stereotactic arrhythmia radioablation (STAR) is a promising non-invasive therapy for patients with ventricular tachycardia (VT). Accurate identification of the arrhythmogenic volume, or clinical target volume (CTV), on the radiotherapy (RT) 4D planning computed tomography (CT) scan is key for STAR efficacy and safety. This case report illustrates our workflow of electro-structural image integration for CTV delineation. Case summary A 72-year-old man with ischaemic cardiomyopathy and VT storm, despite two (endocardial and epicardial) catheter-based ablations, was consented for STAR. A 3D electro-structural arrhythmia model was generated from co-registered electroanatomical voltage and activation maps, electrocardiographic (ECG) imaging, and the cardiac CT angiography scan (in ADAS 3D), pinpointing the VT isthmus and inferoapical VT exit. At this location, an area with short recovery times was found with ECG imaging. A multidisciplinary team delineated the CTV on the transmural ventricular myocardium, which was fused with the 4D planning CT scan using a digital images and communication in medicine (DICOM) radiotherapy file. The CTV was 63% smaller compared with using the conventional American Heart Association 17-segment approach (11 vs. 24 cm3). A single fraction of 25 Gy was delivered to the internal target volume. After an 8-week blanking period, no VT recurrences or radiation-related side-effects were noted. Eight months later, the patient died from end-stage heart failure. Discussion We report a novel workflow for 3D-targeted and ECG imaging-aided CTV delineation for STAR, resulting in a smaller irradiated volume compared with segmental approaches. Acute and intermediate outcome and safety were favourable. Non-invasive ECG imaging at baseline and during induced VT holds promise for STAR guidance.

Case Report: Emergency endovascular management of a ruptured giant abdominal aortic aneurysm with severely angulated and conical shaped neck using novel multiple stiff wire technique

Background Ruptured abdominal aortic aneurysm (rAAA) is commonly fatal, with an overall mortality rate of nearly 90%, and the risk of subsequent rupture remains high, especially in large aneurysm diameters or progressive disease. Unfavorable neck anatomy in EVAR is linked to early graft failure and long-term complications. Recently, a novel multiple stiff wire (MSW) technique has been developed to overcome the challenges of hostile neck anatomy without introducing additional devices and procedural complexity. It has also been feasible in a series of elective cases. In this case, we report the first-ever utilization of the MSW technique in an emergency case of an acute contained rAAA with a conical-shaped, severely angulated neck who underwent Endovascular Aortic Repair (EVAR). Case presentation A 61-year-old man came with intermittent sharp stomach pain radiating to his back since three weeks ago. Physical examination showed elevated blood pressure and anemic conjunctiva. Laboratory examinations showed anemia, leukocytosis, elevated D-dimer level, high creatinine level, and low eGFR. CT-Scan Angiography (CTA) revealed severely hostile anatomy, a conical-shaped abdominal aorta aneurysm with a length of 13.2 cm and a maximum diameter of 9.3 cm with angulation of 90.1°. The patient was diagnosed with Ruptured AAA with a conical-shaped, severely angulated neck. Endovascular Aortic Repair (EVAR) management with MSW technique was planned for him. After four days, The patient was discharged in a clinically stable condition with optimal medical treatment and education. Conclusion The endovascular approach could be performed in emergency settings and has been proven to reduce length of stay, mortality, and morbidity rates. In this case, the endovascular approach with the MSW technique showed promising results for the patient.

Morphology and arterial supply of the pyramidalis muscle in an Australian female population using computed tomography angiography

IntroductionThe structure and function of the human anterolateral abdominal wall have been thoroughly described. However, there has been limited anatomical study of the pyramidalis muscle and its arterial supply. The aim of this study was to analyse the patterns of arterial supply to the pyramidalis in a female population.MethodsA retrospective study of 32 computed tomography angiography scans of the abdominal wall of adult women was performed to assess the prevalence (bilateral or unilateral presence, or absence), morphology (medial border height, base width and thickness) of pyramidalis and patterns of arterial supply.ResultsPyramidalis prevalence was bilateral in 75% of computed tomography angiography studies (24/32), unilateral in 6.3% (2/32) and absent in 18.8% (6/32). Of the five patterns of pyramidalis arterial supply observed and described in detail, the most frequent (68%, 34/50 of cases) originated from an exclusive muscular branch of the inferior epigastric artery. Origin from the pubic branch of the inferior epigastric artery was seen in 4% (2/50). There was a single case (2%, 1/50) of artery origin from a variant obturator artery, a common trunk with the pubic branch from the inferior epigastric artery, and from the muscular branch to rectus abdominis. The artery could not be defined in 22% (11/50).ConclusionIn this computed tomography angiography study of women, five patterns of Pyramidalis arterial supply were identified. In the majority of cases, the pyramidalis derived its arterial supply from an exclusive, isolated muscular branch of the inferior epigastric artery.

Role of Computed Tomography Angiography Enhancement Ratio in Predicting Prognosis in Patients With Stroke Undergoing Endovascular Treatment

Background The computed tomography angiography enhancement ratio (CTA‐ER), calculated through the net water uptake formula, is a valuable predictive tool for detecting adverse events after stroke. However, limited research has investigated the correlation between CTA‐ER and the prognosis of patients receiving endovascular treatment. Therefore, we aimed to examine whether CTA‐ER could predict favorable outcomes in patients undergoing endovascular treatment. Methods We conducted a retrospective study enrolling patients with acute anterior circulation large‐vessel occlusive stroke undergoing endovascular treatment between January 2016 and January 2023. All patients received noncontrast computed tomography and computed tomography angiography scans upon admission. Multivariate logistic regression analysis and receiver operator characteristic curve were used to assess the predictive efficacy in determining favorable outcomes. The favorable outcome at 90 days was a modified Rankin scale score of 0 to 2. Results A total of 206 participants (median age, 68 [60–77] years; 77 women) were included in the study, with 82 (39.8%) individuals demonstrating favorable outcomes. Patients with favorable outcomes had lower noncontrast computed tomography net water uptake (6.42% versus 7.76%; P &lt; 0.001) and CTA‐ER (8.31% versus 10.56%; P &lt; 0.001). Multivariate logistic regression analysis identified that CTA‐ER was a significant predictor for favorable outcomes ( P &lt;0.05 in all models). Furthermore, the receiver operator characteristic analysis revealed that CTA‐ER exhibited superior predictive performance, surpassing noncontrast computed tomography net water uptake (area under the curve, 0.707 versus 0.636, Delong test; P = 0.046). Conclusion CTA‐ER is a significant predictor of favorable outcomes in patients with acute large‐vessel occlusion stroke undergoing endovascular treatment.

Diagnostic Performance of a Deep Learning-Powered Application for Aortic Dissection Triage Prioritization and Classification.

This multicenter retrospective study evaluated the diagnostic performance of a deep learning (DL)-based application for detecting, classifying, and highlighting suspected aortic dissections (ADs) on chest and thoraco-abdominal CT angiography (CTA) scans. CTA scans from over 200 U.S. and European cities acquired on 52 scanner models from six manufacturers were retrospectively collected and processed by CINA-CHEST (AD) (Avicenna.AI, La Ciotat, France) device. The diagnostic performance of the device was compared with the ground truth established by the majority agreement of three U.S. board-certified radiologists. Furthermore, the DL algorithm's time to notification was evaluated to demonstrate clinical effectiveness. The study included 1303 CTAs (mean age 58.8 ± 16.4 years old, 46.7% male, 10.5% positive). The device demonstrated a sensitivity of 94.2% [95% CI: 88.8-97.5%] and a specificity of 97.3% [95% CI: 96.2-98.1%]. The application classified positive cases by the AD type with an accuracy of 99.5% [95% CI: 98.9-99.8%] for type A and 97.5 [95% CI: 96.4-98.3%] for type B. The application did not miss any type A cases. The device flagged 32 cases incorrectly, primarily due to acquisition artefacts and aortic pathologies mimicking AD. The mean time to process and notify of potential AD cases was 27.9 ± 8.7 s. This deep learning-based application demonstrated a strong performance in detecting and classifying aortic dissection cases, potentially enabling faster triage of these urgent cases in clinical settings.

Inter- and Intra-observer Agreement of the Peripheral Arterial Calcium Scoring System in Patients Undergoing (Infra)Popliteal Endovascular Interventions

PurposePeripheral arterial calcification is an important predictor of outcomes after both conservative and endovascular treatment. Digital subtraction angiography (DSA)-based calcification scores are limited by low sensitivity and inter-observer agreement. The Peripheral Arterial Calcium Scoring System (PACSS) assesses the severity of target lesion calcification. The newly introduced modified PACSS (mPACSS) also evaluates target vessel calcification. This study aimed to assess the inter- and intra-observer reliability of PACSS and mPACSS on computed tomography angiography (CTA) in (infra)popliteal endovascular interventions.MethodsA random sample of 50 limbs from the prospective multicenter Dutch Chronic Lower Limb-Threatening Ischemia Registry (THRILLER) were included. Three experienced independent raters scored PACSS on CTA. Three months later, one blinded rater assessed the same 50 CTA scans, keeping track of assessment time. The reliability of the original 5-step PACSS, a simplified binary PACSS (0–2 vs 3–4) and the 7-step mPACSS were tested using Cohen’s and Fleiss’ kappa statistics.ResultsIn total, 50 limbs (mean age 70.1 ± 11.0, 29 men) with 41 popliteal and 40 infrapopliteal lesions were scored. Inter-observer agreement of PACSS and binary PACSS were moderate (κ = 0.60) and substantial (κ = 0.72), respectively, while intra-observer agreement was almost perfect in both scores (κ = 0.86). Inter- and intra-observer agreement of mPACSS were moderate (κ = 0.48) and substantial (κ = 0.77), respectively. Mean assessment time for an experienced rater was 3.43 ± 0.93 min per CTA scan.ConclusionBoth the semi-quantitative PACSS and mPACSS scores for (infra)popliteal arteries can be performed reliably on pre-operative CTA.Graphic

TLF: Triple learning framework for intracranial aneurysms segmentation from unreliable labeled CTA scans

Intracranial aneurysm (IA) is a prevalent disease that poses a significant threat to human health. The use of computed tomography angiography (CTA) as a diagnostic tool for IAs remains time-consuming and challenging. Deep neural networks (DNNs) have made significant advancements in the field of medical image segmentation. Nevertheless, training large-scale DNNs demands substantial quantities of high-quality labeled data, making the annotation of numerous brain CTA scans a challenging endeavor. To address these challenges and effectively develop a robust IAs segmentation model from a large amount of unlabeled training data, we propose a triple learning framework (TLF). The framework primarily consists of three learning paradigms: pseudo-supervised learning, contrastive learning, and confident learning. This paper introduces an enhanced mean teacher model and voxel-selective strategy to conduct pseudo-supervised learning on unreliable labeled training data. Concurrently, we construct the positive and negative training pairs within the high-level semantic feature space to improve the overall learning efficiency of the TLF through contrastive learning. In addition, a multi-scale confident learning is proposed to correct unreliable labels, which enables the acquisition of broader local structural information instead of relying on individual voxels. To evaluate the effectiveness of our method, we conducted extensive experiments on a self-built database of hundreds of cases of brain CTA scans with IAs. Experimental results demonstrate that our method can effectively learn a robust CTA scan-based IAs segmentation model using unreliable labeled data, outperforming state-of-the-art methods in terms of segmentation accuracy. Codes are released at https://github.com/XueShuangqian/TLF.

Development and first implementation of a novel multi-modality cardiac motion and dosimetry phantom for radiotherapy applications.

Cardiac applications in radiation therapy are rapidly expanding including magnetic resonance guided radiation therapy (MRgRT) for real-time gating for targeting and avoidance near the heart or treating ventricular tachycardia (VT). This work describes the development and implementation of a novel multi-modality and magnetic resonance (MR)-compatible cardiac phantom. The patient-informed 3D model was derived from manual contouring of a contrast-enhanced Coronary Computed Tomography Angiography scan, exported as a Stereolithography model, then post-processed to simulate female heart with an average volume. The model was 3D-printed using Elastic50A to provide MR contrast to water background. Two rigid acrylic modules containing cardiac structures were designed and assembled, retrofitting to an MR-safe programmable motor to supply cardiac and respiratory motion in superior-inferior directions. One module contained a cavity for an ion chamber (IC), and the other was equipped with multiple interchangeable cavities for plastic scintillation detectors (PSDs). Images were acquired on a 0.35 T MR-linac for validation of phantom geometry, motion, and simulated online treatment planning and delivery. Three motion profiles were prescribed: patient-derived cardiac (sine waveform, 4.3mm peak-to-peak, 60 beats/min), respiratory (cos4 waveform, 30mm peak-to-peak, 12 breaths/min), and a superposition of cardiac (sine waveform, 4mm peak-to-peak, 70 beats/min) and respiratory (cos4 waveform, 24mm peak-to-peak, 12 breaths/min). The amplitude of the motion profiles was evaluated from sagittal cine images at eight frames/s with a resolution of 2.4mm × 2.4mm. Gated dosimetry experiments were performed using the two module configurations for calculating dose relative to stationary. A CT-based VT treatment plan was delivered twice under cone-beam CT guidance and cumulative stationary doses to multi-point PSDs were evaluated. No artifacts were observed on any images acquired during phantom operation. Phantom excursions measured 49.3±25.8%/66.9±14.0%, 97.0±2.2%/96.4±1.7%, and 90.4±4.8%/89.3±3.5% of prescription for cardiac, respiratory, and cardio-respiratory motion profiles for the 2-chamber (PSD) and 12-substructure (IC) phantom modules respectively. In the gated experiments, the cumulative dose was<2% from expected using the IC module. Real-time dose measured for the PSDs at 10Hz acquisition rate demonstrated the ability to detect the dosimetric consequences of cardiac, respiratory, and cardio-respiratory motion when sampling of different locations during a single delivery, and the stability of our phantom dosimetric results over repeated cycles for the high dose and high gradient regions. For the VT delivery, high dose PSD was<1% from expected (5-6 cGy deviation of 5.9Gy/fraction) and high gradient/low dose regions had deviations<3.6% (6.3 cGy less than expected 1.73Gy/fraction). A novel multi-modality modular heart phantom was designed, constructed, and used for gated radiotherapy experiments on a 0.35 T MR-linac. Our phantom was capable of mimicking cardiac, cardio-respiratory, and respiratory motion while performing dosimetric evaluations of gated procedures using IC and PSD configurations. Time-resolved PSDs with small sensitive volumes appear promising for low-amplitude/high-frequency motion and multi-point data acquisition for advanced dosimetric capabilities. Illustrating VT planning and delivery further expands our phantom to address the unmet needs of cardiac applications in radiotherapy.

Clinical Validation of a Deep Learning Algorithm for Automated Coronary Artery Disease Detection and Classification Using a Heterogeneous Multivendor Coronary Computed Tomography Angiography Data Set.

We sought to clinically validate a fully automated deep learning (DL) algorithm for coronary artery disease (CAD) detection and classification in a heterogeneous multivendor cardiac computed tomography angiography data set. In this single-centre retrospective study, we included patients who underwent cardiac computed tomography angiography scans between 2010 and 2020 with scanners from 4 vendors (Siemens Healthineers, Philips, General Electrics, and Canon). Coronary Artery Disease-Reporting and Data System (CAD-RADS) classification was performed by a DL algorithm and by an expert reader (reader 1, R1), the gold standard. Variability analysis was performed with a second reader (reader 2, R2) and the radiologic reports on a subset of cases. Statistical analysis was performed stratifying patients according to the presence of CAD (CAD-RADS >0) and obstructive CAD (CAD-RADS ≥3). Two hundred ninety-six patients (average age: 53.66 ± 13.65, 169 males) were enrolled. For the detection of CAD only, the DL algorithm showed sensitivity, specificity, accuracy, and area under the curve of 95.3%, 79.7%, 87.5%, and 87.5%, respectively. For the detection of obstructive CAD, the DL algorithm showed sensitivity, specificity, accuracy, and area under the curve of 89.4%, 92.8%, 92.2%, and 91.1%, respectively. The variability analysis for the detection of obstructive CAD showed an accuracy of 92.5% comparing the DL algorithm with R1, and 96.2% comparing R1 with R2 and radiology reports. The time of analysis was lower using the DL algorithm compared with R1 (P < 0.001). The DL algorithm demonstrated robust performance and excellent agreement with the expert readers' analysis for the evaluation of CAD, which also corresponded with significantly reduced image analysis time.

Midterm survival after aortic repair versus conservative treatment in patients with penetrating aortic ulcer.

Background: The clinical outcomes and survival of patients with penetrating aortic ulcers (PAU) were evaluated in a tertiary care hospital, comparing those who underwent aortic repair to those treated conservatively. Patients and methods: A retrospective single-centre analysis included all patients that underwent a computed tomography angiography (CT-A) scan with the diagnosis of a PAU between January 2009 and May 2019. "PAU" was identified in 1,493 of 112,506 CT-A scan reports in 576 patients. Clinical and angiomorphological data were collected. The primary outcome was overall survival (OS), with secondary outcomes focusing on identifying risk factors for poor OS. Survival probabilities were analysed by the Kaplan-Meier method using the log-rank test. A Cox hazard model using survival as dependent variable with stepwise backward eliminations based on the likelihood ratios was employed. Results: 315 PAUs were identified in 278 patients. The prevalence in the cohort was 0.8%. The mean age of the patients was 74.4 years, and they were predominantly male (n = 208, 74.8%). The mean ulcer depth was 11.8 mm (range 2-50 mm). Out of the patients, 232 were asymptomatic (83.5%). Among 178 PAUs (56.5%), high-risk factors, such as ulcer depth >10 mm, aortic diameter >40 mm, and ulcer length >20 mm, were observed. Aortic repair was associated with a better mean OS compared to conservatively managed patients (72.6 versus 32.2 months, p = 0.001). The Cox hazard model showed that ulcer depth >1 mm was associated with poor OS (HR 0.67, p = 0.048), while aortic repair was related to a better OS (HR 4.365, p<0.013). Conclusions: Aortic repair is associated with better OS, but this finding should be interpreted with caution because of differences in age and comorbidities between the groups. Further evaluation is warranted through prospective studies with randomized groups. Further assessment for angiomorphological parameters is recommended to identify patients at increased risk for poor OS.