Imaging Evaluation Research Articles

Computed Tomographic Evaluation of Shaping Ability of Rotating or Reciprocating files through Modified Contracted Access Cavity

Computed Tomographic Evaluation of Shaping Ability of Rotating or Reciprocating files through Modified Contracted Access Cavity

Appearance of New Lesions Associate With Poor Prognosis in Pembrolizumab-Treated Urothelial Carcinoma

ObjectivesThis study investigated the variations in response patterns, including target lesion enlargement and the emergence of new lesions, in patients with urothelial carcinoma receiving pembrolizumab therapy and assessed the impact of new lesions on patient outcomes. MethodsThis retrospective analysis included patients with urothelial carcinoma treated with pembrolizumab following platinum failure. Response Evaluation Criteria in Solid Tumors criteria were used to assess the target lesion size and appearance of new lesions. Patients were categorized into 2 groups: the primary progressive disease (PD) group, consisting of patients who progressed within 28 to 84 days of treatment initiation, and the secondary PD group, consisting of patients who progressed more than 84 days after treatment initiation. Survival analyses were performed to evaluate the impact of new lesions on patient outcomes. ResultsIn this study, 42 patients experienced primary PD, and 37 experienced secondary PD. Among patients with primary PD, 64.3%, 73.8%, 45.2% had an increase of 20% or more in target lesion size, newly emerged lesions, and both an increase in target lesion size and new lesions, respectively. Kaplan–Meier analysis revealed that patients with primary PD and new lesions had significantly shorter overall survival after PD than those with only target lesion growth and those with secondary PD (both P < .001). ConclusionThis study revealed the heterogeneity of response patterns during pembrolizumab therapy in patients with urothelial carcinoma and primary pembrolizumab resistance and the presence of new lesions early in treatment. Earlier imaging evaluation should be performed to assess for the appearance of new lesions, leading to sequential treatment.

Multimodality Imaging Evaluation of Tumour Peeking Its Head Into the Right Atrium

Multimodality Imaging Evaluation of Tumour Peeking Its Head Into the Right Atrium

Ultrasounds outperform magnetic resonance imaging in quantifying meniscal extrusion in patients with knee osteoarthritis.

The aim of this study was to quantify meniscal extrusion through ultrasound (US) evaluation in supine and standing positions and to compare the results with those documented through magnetic resonance (MR) imaging in patients affected by knee osteoarthritis (OA). Sixty patients (38 men, 22 women, mean age 60.8 ± 9.7 years) with knee OA were enrolled and underwent a 1.5 T MR evaluation and an US examination of the symptomatic OA knee for the evaluation of the medial and lateral meniscus extrusion both in the supine clinostatic position (clino-US) with the knee fully extended and in the standing weight-bearing orthostatic position (ortho-US). For the three imaging evaluations (MR, clino-US and ortho-US), both semi-quantitative and quantitative measurements were performed. The quantitative analysis documented higher values of medial meniscal extrusion at the ortho-US evaluation (5.2 ± 2.3 mm) compared to MR (4.2 ± 2.2, p < 0.0005) and clino-US (4.5 ± 2.3, p < 0.0005) and of the lateral meniscus at the ortho-US evaluation (4.3 ± 1.8) compared to MR (3.3 ± 1.6, p < 0.0005) and clino-US (3.8 ± 1.6, p < 0.0005). The semi-quantitative analysis confirmed the same trend for both menisci. Higher extrusion values were documented in women and more advanced OA, as well as in older patients with higher body mass index, the latter being underestimated the most by the MR approach. US outperforms MR imaging in quantifying meniscal extrusion in patients with knee OA. Moreover, the highest values of meniscal extrusion have been documented using US in standing position compared to the supine position, underlining the importance of the weight-bearing assessment of meniscal extrusion in knee OA patients. II.

Supervised deep learning-based synthetic computed tomography from kilovoltage cone-beam computed tomography images for adaptive radiation therapy in head and neck cancer.

To generate and investigate a supervised deep learning algorithm for creating synthetic computed tomography (sCT) images from kilovoltage cone-beam computed tomography (kV-CBCT) images for adaptive radiation therapy (ART) in head and neck cancer (HNC). This study generated the supervised U-Net deep learning model using 3,491 image pairs from planning computed tomography (pCT) and kV-CBCT datasets obtained from 40 HNC patients. The dataset was split into 80% for training and 20% for testing. The evaluation of the sCT images compared to pCT images focused on three aspects: Hounsfield units accuracy, assessed using mean absolute error (MAE) and root mean square error (RMSE); image quality, evaluated using the peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM) between sCT and pCT images; and dosimetric accuracy, encompassing 3D gamma passing rates for dose distribution and percentage dose difference. MAE, RMSE, PSNR, and SSIM showed improvements from their initial values of 53.15 ± 40.09, 153.99 ± 79.78, 47.91 ± 4.98 dB, and 0.97 ± 0.02 to 41.47 ± 30.59, 130.39 ± 78.06, 49.93 ± 6.00 dB, and 0.98 ± 0.02, respectively. Regarding dose evaluation, 3D gamma passing rates for dose distribution within sCT images under 2%/2 mm, 3%/2 mm, and 3%/3 mm criteria, yielded passing rates of 92.1% ± 3.8%, 93.8% ± 3.0%, and 96.9% ± 2.0%, respectively. The sCT images exhibited minor variations in the percentage dose distribution of the investigated target and structure volumes. However, it is worth noting that the sCT images exhibited anatomical variations when compared to the pCT images. These findings highlight the potential of the supervised U-Net deep learningmodel in generating kV-CBCT-based sCT images for ART in patients with HNC.

Atypical tuberculous peritonitis presenting as a peritoneal pseudocyst in an immunocompetent adult: insights from a case and literature review

BackgroundTuberculous peritonitis often presents with nonspecific symptoms that can lead to diagnostic challenges, particularly when manifesting as peritoneal pseudocysts. This study highlights the clinical complexity and diagnostic approach of tuberculous peritonitis presented as a pseudocyst in an immunocompetent adult, an atypical scenario that is rarely documented.Case presentationWe report a detailed case of a 41-year-old man presenting with abdominal distension, pain, and significant weight loss over four months. Abdominal CT showed a peritoneal pseudocyst, initially misdiagnosed due to its resemblance to more common abdominal pathologies. The diagnosis of tuberculous peritonitis was confirmed through histopathological analysis. Additionally, a systematic literature review was conducted to identify and analyse similar cases, focusing on clinical presentations, diagnostic methods, and patient outcomes. Our patient exhibited classic symptoms of abdominal TB but was unique due to the absence of prior ventriculoperitoneal shunting, a common factor in similar cases. Our literature review found that such presentations typically result in diagnostic delays averaging five months, complicating patient management and outcomes. This review also underscores the importance of considering tuberculosis in the differential diagnosis of peritoneal pseudocysts, particularly in TB-endemic regions.ConclusionThis case and review emphasize the need for high clinical suspicion and prompt investigation of tuberculosis in patients presenting with atypical abdominal symptoms and pseudocysts. Improved diagnostic strategies, including early use of imaging and pathological evaluations, are essential for timely diagnosis and management, thereby improving patient outcomes in suspected cases of extrapulmonary tuberculosis.

Is Surgical Removal of Asymptomatic Third Molars in the Horizontal III-C Position Advisable? A Pilot Study of Tomographic Evaluation

Is Surgical Removal of Asymptomatic Third Molars in the Horizontal III-C Position Advisable? A Pilot Study of Tomographic Evaluation

The Accuracy of Radiographers Preliminary Image Evaluations of Axial Radiographs: a Prospective Longitudinal Study at Al-Hussein Hospital, Iraq

Introduction: Modern emergency departments are under increasing pressure that can only be alleviated by new approaches to meeting demand. One strategy could be the adoption of radiographer preliminary image evaluations (PIEs), which would significantly reduce the time it takes emergency teams to receive critical imagery results. The aim of this study was to examine the accuracy of radiographers’ interpretations of axial radiographs and the impact a short training program had on their image interpretation skills. Methods: Forty-one radiographers volunteered to participate in the study. From 15 January to 15 April 2023 radiographers produced PIEs for 24 axial radiographs which were compared to the radiology reports for the same images. The accuracy each of the radiographers’ PIEs were categorized as true positive, true negative, false positive and false negative, with numerical scores to enable mean accuracies to be calculated. The radiographers’ accuracy was then reassessed on the same images after they had completed a two-week training program on axial skeletal radiograph interpretation. Results: The study reported that demonstrated that most (TP) radiographer PIEs (M = 5.66, SD = 1.24) were about facial bone fracture. Moreover, this study demonstrated that most (FN/TP) radiographer PIEs (M = 3.83, SD = 1.69) were that cases about inflammatory disease of the axial spine, such as ankylosing spondylitis. In contrast, the most common cases misinterpreted were about cervical spine disorders such as diffuse idiopathic skeletal hyperostosis (DISH) (M = 2.49, SD = 1.36). Years of experience in radiography showed a positive but not statistically significant influence on accuracy. Additionally, post training mean accuracy significantly improved. Conclusion: This study found radiographers provided quite accurate PIEs for facial bone fractures when compared to the full radiology reports of the same images. The findings also highlighted specific pathologies that were frequently misinterpreted. A two-week training program was found to be effective at improving radiographers’ ability to correctly identify and describe abnormalities present in axial radiographs.

Three-Dimensional Printed Silk Fibroin/Hyaluronic Acid Scaffold with Functionalized Modification Results in Excellent Mechanical Strength and Efficient Endogenous Cell Recruitment for Articular Cartilage Regeneration.

Treatment of articular cartilage remains a great challenge due to its limited self-repair capability. In tissue engineering, a scaffold with both mechanical strength and regenerative capacity has been highly desired. This study developed a double-network scaffold based on natural biomaterials of silk fibroin (SF) and methacrylated hyaluronic acid (MAHA) using three-dimensional (3D) printing technology. Structural and mechanical characteristics of the scaffold was first investigated. To enhance its ability of recruiting endogenous bone marrow mesenchymal stem cells (BMSCs), the scaffold was conjugated with a proven BMSC-specific-affinity peptide E7, and its biocompatibility and capacity of cell recruitment were assessed in vitro. Animal experiments were conducted to evaluate cartilage regeneration after transplantation of the described scaffolds. The SF/HA scaffolds exhibited a hierarchical macro-microporous structure with ideal mechanical properties, and offered a 3D spatial microenvironment for cell migration and proliferation. In vitro experiments demonstrated excellent biocompatibility of the scaffolds to support BMSCs proliferation, differentiation, and extracellular matrix production. In vivo, superior capacity of cartilage regeneration was displayed by the SF/MAHA + E7 scaffold as compared with microfracture and unconjugated SF/MAHA scaffold based on macroscopic, histologic and imaging evaluation. In conclusion, this structurally and functionally optimized SF/MAHA + E7 scaffold may provide a promising approach to repair articular cartilage lesions in situ.

Pediatric mediastinal lymphatic malformation: misdiagnosis analysis and literature review

ObjectivesMediastinal cystic lymphatic malformation (MCLM) in children is prone to misdiagnosis as cystic teratoma. We compared the clinical and radiologic features between the two diseases and performed a cross-comparison with previous research on adult cases. This study aims to identify characteristic pediatric manifestations to improve diagnostic accuracy.MethodsA retrospective study of clinical and radiologic data was conducted on 12 MCLM and 20 cases of cystic teratomas confirmed by pathology or intervention biopsy. Clinical characters and radiology features (mass location and morphology, density, component, secondary complication) were recorded and compared. We reviewed clinical studies on MCLM published in the past decades, analyzing radiological differences and comparing pediatric MCLM cases at our hospital with those in the literature.ResultsGroup comparison in pediatrics between MCLM and cystic teratomas: There were significant age differences (p = 0.036), shape (p = 0.003), CT difference value (p < 0.001), CT difference ratio (p < 0.001), calcification (p < 0.001), fat (p < 0.001), and typing (p < 0.001) between the two diseases. An analysis of literature data on MCLM cases involved 16 studies.ConclusionThe absence of internal fat or irregular morphology, along with a minimal CT difference value, may suggest the diagnosis of MCLM. In pediatric cases, anterior mediastinal diseases tend to extend toward the neck, and the presence of the thymus can complicate the component analysis, thereby increasing the risk of misdiagnosis. Clinical diagnosis and differential diagnosis of pediatric MCLM rely heavily on imaging evaluation.

The Spectrum of Adrenal Lesions in a Tertiary Referral Center.

Adrenal tumors are a common finding in clinical practice, and only detailed evaluation may reveal secretory and metabolic abnormalities or their malignant character. We aimed to highlight epidemiological data, rates of malignancy, clinical or secretory characteristics, and the cardiometabolic implications of adrenal masses. We conducted a retrospective analysis using data from the medical files of 474 patients with adrenal pathology hospitalized between January 2007 and January 2020, before the COVID-19 pandemic, using the ICD-10 codes. After applying inclusion and exclusion criteria, a total of 264 patients with adrenal tumors were enrolled in the study. Patients underwent clinical examination, abdominal imaging, and hormonal evaluation, and some of them underwent a pathological exam after adrenalectomy. Median age at diagnosis was 56 (17) years, with 81.06% of patients being female. The median follow-up period was 41.5 (70) months, ranging from 6 months to 13 years. Adrenal tumors were most frequently seen in older female patients, with 83.47% of them being over 40 years old. The malignancy rate was 4.54%. Hormonally nonfunctioning tumors (71.95%) predominated, and overt hypercortisolism was present in 10.61% of patients, as was mild autonomous cortisol secretion in 5.31% of patients, primary hyperaldosteronism in 8.71% of patients, and adrenal paraganglioma in 3.41% of patients. Cardiometabolic comorbid conditions were similar in patients with functioning and nonfunctioning tumors. All patients with adrenal tumors should receive a complete hormonal workup and detailed malignancy risk assessment. Even though a hormonally active tumor predisposes to cardiometabolic comorbid conditions, a nonfunctioning lesion may also be associated with such disorders and needs thorough assessment.

A quality assessment tool for focused abdominal sonography for trauma examinations using artificial intelligence.

Current tools to review focused abdominal sonography for trauma (FAST) images for quality have poorly defined grading criteria or are developed to grade the skills of the sonographer and not the examination. The purpose of this study is to establish a grading system with substantial agreement among coders, thereby enabling the development of an automated assessment tool for FAST examinations using artificial intelligence (AI). Five coders labeled a set of FAST clips. Each coder was responsible for a different subset of clips (10% of the clips were labeled in triplicate to evaluate intercoder reliability). The clips were labeled with a quality score from 1 (lowest quality) to 5 (highest quality). Clips of 3 or greater were considered passing. An AI training model was developed to score the quality of the FAST examination. The clips were split into a training set, a validation set, and a test set. The predicted scores were rounded to the nearest quality level to distinguish passing from failing clips. A total of 1,514 qualified clips (1,399 passing and 115 failing clips) were evaluated in the final data set. This final data set had a 94% agreement between pairs of coders on the pass/fail prediction, and the set had a Krippendorff α of 66%. The decision threshold can be tuned to achieve the desired tradeoff between precision and sensitivity. Without using the AI model, a reviewer would, on average, examine roughly 25 clips for every 1 failing clip identified. In contrast, using our model with a decision threshold of 0.015, a reviewer would examine roughly five clips for every one failing clip - a fivefold reduction in clips reviewed while still correctly identifying 85% of passing clips. Integration of AI holds significant promise in improving the accurate evaluation of FAST images while simultaneously alleviating the workload burden on expert physicians. Diagnostic Test/Criteria; Level II.

The Development and Evaluation of a Novel Highly Selective PET Radiotracer for Targeting BET BD1.

Background/Objectives: Small molecules that interfere with the interaction between acetylated protein tails and the tandem bromodomains of BET (bromodomain and extra-terminal) family proteins are pivotal in modulating immune/inflammatory and neoplastic diseases. This study aimed to develop a novel PET imaging tracer, [11C]GSK023, that targets the N-terminal bromodomain (BD1) of BET family proteins with high selectivity and potency, thereby enriching the chemical probe toolbox for epigenetic imaging. Methods: [11C]GSK023, a radio-chemical probe, was designed and synthesized to specifically target the BET BD1. In vivo PET imaging evaluations were conducted on rodents, focusing on the tracer's distribution and binding specificity in various tissues. Blocking studies were performed to confirm the probe's selectivity and specificity. Results: The evaluations revealed that [11C]GSK023 demonstrated good uptake in peripheral organs with limited brain penetration. Further blocking studies confirmed the probe's high binding specificity and selectivity for the BET BD1 protein, underscoring its potential utility in epigenetic imaging. Conclusions: The findings suggest that [11C]GSK023 is a promising PET probe for imaging the BET BD1 protein, offering the potential to deepen our understanding of the roles of BET bro-modomains in disease and their application in clinical settings to monitor disease progression and therapeutic responses.

Enhancing skin aging parameter assessment in clinical trials: AI-Driven analysis of ultrasound images

BackgroundHigh-frequency ultrasound (HFUS) imaging offers valuable insights into skin aging parameters in clinical trials. However, manual measurements are time-consuming and operator-dependent, necessitating the exploration of automated approaches. ObjectiveThis study aimed to develop, train, and validate an artificial intelligence model for automated HFUS image parameter acquisition in dermatological assessments. A secondary goal was its application in evaluating data from an anti-aging skin therapy clinical trial. MethodsSupervised machine learning algorithms were used to predict target variables from ultrasound images. The best models were selected through independent validation. A training dataset of 144 ultrasound skin images and a validation set of 40 images were employed. A clinical trial involved 34 female subjects with aging skin signs, randomized into two groups: (1) cosmetic formulation plus therapeutic unfocused ultrasound (TUS) and (2) placebo formulation plus TUS. HFUS imaging was conducted before and after a 4-week and 8-week study period. ResultsOur algorithms successfully predicted echogenicity and thickness variables, showing competitive performance. In the clinical trial, the treatment group exhibited a significant improvement in skin echogenicity, while no significant changes were observed in the placebo group. ConclusionThis study demonstrates the feasibility of automating the prediction of bioimage variables for anti-aging strategy development. Mathematical algorithms reduced HFUS image evaluations to minutes, expediting clinical trial progress.

Evaluation of Social Appearance Anxiety, Self-Esteem, Eating Behavior, and Body Image in Rhinoplasty and Septoplasty Patients

Evaluation of Social Appearance Anxiety, Self-Esteem, Eating Behavior, and Body Image in Rhinoplasty and Septoplasty Patients

A novel carboxylesterase 2-targeted fluorescent probe with cholic acid as a recognition group for early diagnosis of drug- and environment-related liver diseases

Due to the detrimental effects of various harmful substances—such as carcinogens, drug toxicity, and environmental pollutants—on the liver, which can trigger or exacerbate conditions like hepatocellular carcinoma (HCC), drug-induced liver injury (DILI), and non-alcoholic fatty liver disease (NAFLD), accurate detection and monitoring of these diseases are crucial for effective treatment. Carboxylesterase 2 (CES2) is primarily found in the liver and, as a potential biomarker, its accurate detection can enhance the early diagnosis and treatment efficacy of liver diseases. Traditional fluorescence probes for CES2 detection suffer from non-specific recognition groups, leading to poor targeting specificity. To address this limitation, we propose a novel CES2-responsive fluorescent probe utilizing cholic acid (CA) as a recognition group. The probe, LAN-CA, was synthesized by esterifying CA with a near-infrared fluorophore, LAN-OH. This novel fluorescent probe leverages the unique affinity of CA for hepatocytes, ensuring that LAN-CA remains and accumulates specifically within the hepatoenteric circulation. In vitro experiments showed that the probe exhibits superior optical performance compared to traditional benzoate-based probe (LAN-PH), with a detection limit of 0.015 μg/mL. Examination of 56 common biological interferents demonstrated that using CA as a recognition group offers high selectivity. Cell experiments confirmed that LAN-CA is an effective tool for monitoring endogenous CES2 in live cells. Comprehensive evaluations of fluorescence imaging in various mouse models of liver diseases, such as HCC, DILI, and NAFLD, demonstrated that LAN-CA provides exceptional imaging accuracy and therapeutic monitoring capabilities. In conclusion, this probe not only can be a promising tool for accurate liver disease diagnosis, but also can provide valuable insights into treatment efficacy.

The Accuracy of Radiographers Preliminary Image Evaluations of Axial Radiographs: a Prospective Longitudinal Study at Al-Hussein Hospital, Iraq

Introduction: Modern emergency departments are under increasing pressure that can only be alleviated by new approaches to meeting demand. One strategy could be the adoption of radiographer preliminary image evaluations (PIEs), which would significantly reduce the time it takes emergency teams to receive critical imagery results. The aim of this study was to examine the accuracy of radiographers’ interpretations of axial radiographs and the impact a short training program had on their image interpretation skills. Methods: Forty-one radiographers volunteered to participate in the study. From 15 January to 15 April 2023 radiographers produced PIEs for 24 axial radiographs which were compared to the radiology reports for the same images. The accuracy each of the radiographers’ PIEs were categorized as true positive, true negative, false positive and false negative, with numerical scores to enable mean accuracies to be calculated. The radiographers’ accuracy was then reassessed on the same images after they had completed a two-week training program on axial skeletal radiograph interpretation. Results: The study reported that demonstrated that most (TP) radiographer PIEs (M 66, SD = 1.24) were about facial bone fracture. Moreover, this study demonstrated that most (FN/TP) radiographer PIEs (M = 3.83, SD = 1.69) were that cases about inflammatory disease of the axial spine, such as ankylosing spondylitis. In contrast, the most common cases misinterpreted were about cervical spine disorders such as diffuse idiopathic skeletal hyperostosis (DISH) (M = 2.49, SD = 1.36). Years of experience in radiography showed a positive but not statistically significant influence on accuracy. Additionally, post training mean accuracy significantly improved. Conclusion: This study found radiographers provided quite accurate PIEs for facial bone fractures when compared to the full radiology reports of the same images. The findings also highlighted specific pathologies that were frequently misinterpreted. A two-week training program was found to be effective at improving radiographers’ ability to correctly identify and describe abnormalities present in axial radiographs.

Magnetic resonance imaging evaluation of the cerebellar tonsil position before and after posterior spinal fusion in adolescent idiopathic scoliosis.

Chiari malformation type I(CM-I) is one of the most common neurological malformations observed in patients with adolescent idiopathic scoliosis (AIS). It remains uncertain whether AIS patients without neurological symptoms require CM-I decompression before undergoing spinal corrective surgery to prevent cerebellar tonsil herniation and potential neurological complications. This study aims to assess variations in the position of the cerebellar tonsil after posterior spinal fusion (PSF) in neurologically intact patients with AIS. We retrospectively evaluated 40 patients with AIS who underwent posterior spinal fusion (PSF) without neurological symptoms. Sagittal hindbrain MRIs were performed before and after spinal surgery. The cerebellar tonsil's position relative to the foramen magnum was measured using the method described by Aboulezz (J Comput Assist Tomogr 1985). We assessed variations in the cerebellar tonsil position concerning spinal correction and elongation after PSF. The average preoperative magnitude of the scoliotic curve was 53.15 degrees (SD 10.46 degrees), and that of thoracic kyphosis was 35.42 degrees (SD 12.38 degrees). In the immediate postoperative period, the average magnitudes were 7.45 degrees (SD 7.33 degrees) and 27.87 degrees (SD 9.03 degrees), respectively. The average correction achieved with PSF was 86% in the coronal plane (p < 0.00001). The average length of the spine in the coronal plane was 44.5cm (SD 5.25cm) preoperatively and 48.27cm (SD 4.40cm) postoperatively (p < 0.00001). The average length of the vertebral column in the sagittal plane was 50.87cm (SD 4.47cm) preoperatively and 55.13cm (SD 3.27cm) postoperatively (p < 0.00001). No significant difference was observed in the position of the cerebellar tonsil in the measurements taken before and after spinal deformity correction (p = 0.6042). In 10 out of 40 patients, caudal displacement of the cerebellar tonsil was observed after PSF. In 28 patients, no variation in the position of the cerebellar tonsil was observed, and in 2, cephalic displacement was noted. In AIS patients with a normal position of the cerebellar tonsil undergoing posterior spinal fusion, there is no significant change in their positionafter surgery. Our analysis did not reveal any correlation between curve correction, spine elongation, and variations in the cerebellar tonsil position. The position of the cerebellar tonsil remained largely unchanged after PSF in AIS patients without neurological symptoms. Further studies would be necessary to determine whether surgical decompression is required in asymptomatic patients with CM-I before undergoing surgery to correct spinal deformity.

MRI-based Quantitative Collateral Assessment in Acute Stroke : AComparison with Single-phase CTA in Drip-and-ship Patients with Serial Imaging.

In acute ischemic stroke with large-vessel occlusion (LVO), collateral assessment with single-phase computed tomography angiography (CTA) might underestimate pial collateral supply in aconsiderable proportion of patients. We aimed to compare time-resolved magnetic resonance imaging (MRI)-based quantitative collateral mapping to conventional collateral imaging with CTA. This retrospective single-center study covering aperiod of 6years (2012-2018) included drip-and-ship LVO patients who underwent MR imaging after initial imaging evaluation with CT. For MRI-based collateral assessment, T2*-weighted time series from perfusion-weighted imaging (PWI) were processed to compute aquantitative collateral vessel index (CVIPWI) based on the magnitude of signal variance across the entire acquisition time. CTA-based collateral scores (Tan and Maas) and CVIPWI were investigated in terms of inter-modality associations between collateral measures, as well as their relationships with stroke severity, infarct volume and early functional outcome. The final analysis included n = 56patients (n = 31female, mean age69.9 ± 14.21 years). No significant relationship was found between MR-based quantitative collateral supply (CVIPWI) and CT-based collateral scores (r = -0.00057, p = 0.502 and r = -0.124, p = 0.797). In contrast to CVIPWI, CTA-based collateral scores showed no significant relationship with clinical stroke severity and infarct volume. While MR-based CVIPWI was independently associated with favorable early functional outcome in multivariate analysis (OR 1.075, 95% CI 1.001-1.153, p = 0.046), CTA-based collateral scores were not significantly associated with outcome. Since collateral scores based on single-phase CTA do not accurately reflect infarct progression and might underestimate pial collateralization in arelevant proportion of patients, they are not associated with early functional outcome in LVO patients. In contrast, CVIPWI represents arobust imaging parameter of collateral supply and is independently associated with functional outcome.

A multi-scale deep residual network-based guided wave imaging evaluation method for fatigue crack quantification

Abstract As a promising structural health monitoring (SHM) technology, guided wave (GW) imaging is gaining increasing attention for crack monitoring of aircraft structures. However, actual fatigue crack propagation is a complex dynamically evolving process affected by various variabilities. It is still challenging to accurately track and quantify the dynamic fatigue crack propagation with GW imaging methods. Therefore, in order to achieve more accurate fatigue crack quantification, this paper proposes a multi-scale deep residual network-based GW imaging evaluation method. A convolutional neural network (CNN) is utilized to evaluate the entire pixel distribution of GW imaging maps to fuse damage-related information from multiple GW monitoring paths. By designing multi-scale convolutional kernels and deep residual learning, a robust quantitative image feature extraction is ensured with the dynamic evolution process of fatigue crack growth and the performance degradation is avoided as the CNN goes deeper, thereby improving the quantification accuracy. The method is validated on a fatigue test of landing gear beams, which are important load-carrying aircraft structural components. The results demonstrate that the proposed method can extract multi-scale crack length-related features and accurately track fatigue crack propagations. For batch specimens, the maximum quantification error is reduced from the original 6.1mm to 1.6mm, marking a significant improvement.