Gadolinium-enhanced Magnetic Resonance Imaging Research Articles

TMIC-72. MECHANISMS TO ENHANCE IMMUNOTHERAPY EFFICACY IN A RAT MODEL OF MEDULLOBLASTOMA

Abstract Medulloblastoma is the most common malignant brain tumor in children. Current treatments are limited by irreversible CNS damage, particularly in high-risk subgroups. Innate immune cells constitute a significant portion of the brain tumor microenvironment, nurturing tumor growth and suppressing key defense mechanisms. Leveraging the innate immune system for improved clinical outcomes remains unrealized. We aimed to determine if Baicalein (Bac), a known tumoricidal M1 macrophage potentiator, improves efficacy in medulloblastoma models. Nude rats (N=10) were implanted with MB002 medulloblastoma intracerebellar patient-derived non-WNT/non-SHH, group 3 xenografts. Baseline T2 and gadolinium-enhanced MRI (Gd-MRI) T1 estimated pre-therapy tumor volumes. Single fraction 2Gy irradiation to the tumor-bearing hemisphere with 20mg/kg temozolomide (CRT) combined with Bac 100mg/kg PO QD daily x8 (N= 3) was administered. CRT alone (N= 3) and no treatment (N= 4) served as controls. Seven days post-therapy, Gd-MRI and histology established tumor volume and CD68 and CD163 expression (T-test; p≤ 0.05). MRI demonstrated the therapeutic effect of Bac+CRT compared to CRT only (P< 0.01) and untreated controls (P= 0.01). This was confirmed via histology volumes; untreated group (P< 0.01) and a trend toward significance vs. CRT only (P= 0.22). The normal brain demonstrated a near significant increase in CD68 expression in the Bac+CRT compared to CRT and control (P< 0.06). A near statistically significant decrease in CD163 expression was observed at the tumor margin for Bac+CRT compared to CRT only (P< 0.06). Likewise when comparing CRT to untreated control (P< 0.05). Preliminary data suggests Bac+CRT uniquely induces an innate immune response within the brain that expresses features of M1 polarization, resulting in effective tumoricidal efficacy in preclinical medulloblastoma models. Current studies are evaluating the mechanisms of efficacious innate immune targeted therapies in larger sample sizes with the eventual goal of clinical translation.

Multiphysics simulations reveal haemodynamic impacts of patient-derived fibrosis-related changes in left atrial tissue mechanics.

Stroke is a leading cause of death and disability worldwide. Atrial myopathy, including fibrosis, is associated with an increased risk of ischaemic stroke, but the mechanisms underlying this association are poorly understood. Fibrosis modifies myocardial structure, impairing electrical propagation and tissue biomechanics, and creating stagnant flow regions where clots could form. Fibrosis can be mapped non-invasively using late gadolinium enhancement magnetic resonance imaging (LGE-MRI). However, fibrosis maps are not currently incorporated into stroke risk calculations or computational electro-mechano-fluidic models. We present multiphysics simulations of left atrial (LA) myocardial motion and haemodynamics using patient-specific anatomies and fibrotic maps from LGE-MRI. We modify tissue stiffness and active tension generation in fibrotic regions and investigate how these changes affect LA flow for different fibrotic burdens. We find that fibrotic regions and, to a lesser extent, non-fibrotic regions experience reduced myocardial strain, resulting in decreased LA emptying fraction consistent with clinical observations. Both fibrotic tissue stiffening and hypocontractility independently reduce LA function, but, together, these two alterations cause more pronounced effects than either one alone. Fibrosis significantly alters flow patterns throughout the atrial chamber, and particularly, the filling and emptying jets of the left atrial appendage (LAA). The effects of fibrosis in LA flow are largely captured by the concomitant changes in LA emptying fraction except inside the LAA, where a multifactorial behaviour is observed. This work illustrates how high-fidelity, multiphysics models can be used to study thrombogenesis mechanisms in patient-specific anatomies, shedding light onto the links between atrial fibrosis and ischaemic stroke. KEY POINTS: Left atrial (LA) fibrosis is associated with arrhythmogenesis and increased risk of ischaemic stroke; its extent and pattern can be quantified on a patient-specific basis using late gadolinium enhancement magnetic resonance imaging. Current stroke risk prediction tools have limited personalization, and their accuracy could be improved by incorporating patient-specific information such as fibrotic maps and haemodynamic patterns. We present the first electro-mechano-fluidic multiphysics computational simulations of LA flow, including fibrosis and anatomies from medical imaging. Mechanical changes in fibrotic tissue impair global LA motion, decreasing LA and left atrial appendage (LAA) emptying fractions, especially in subjects with higher fibrosis burdens. Fibrotic-mediated LA motion impairment alters LA and LAA flow near the endocardium and the whole cavity, ultimately leading to more stagnant blood regions in the LAA.

Biventricular modelling for investigating ventricular arrhythmias in silico

Abstract Background Ventricular arrhythmias have a significant incidence rate worldwide and may potentially lead to sudden cardiac death in severe cases. Despite therapeutic advancements, the intricate mechanisms dictating these arrhythmias remain elusive. Biventricular modelling and deep learning provide a way to investigate the complex electrophysiological substrates underlying cardiac arrhythmogenesis. Purpose This study aims to develop and validate a patient-specific biventricular computational modelling pipeline for simulating ventricular arrhythmias in silico. We provide a comprehensive platform for understanding the initiation, propagation, and treatment response of various ventricular arrhythmias. Methods To facilitate large-scale computational experiments and personalised model predictions within clinical timeframes, it is imperative to establish a rapid and reproducible modelling framework. First, we constructed biventricular volumetric models derived from late gadolinium-enhanced magnetic resonance imaging (LGE-MRI) data from the Cardiac Atlas Project (2018 Atria Segmentation Challenge), and then we calculate biventricular coordinates to facilitate data registration between measures, and fibre and fibrosis inclusion. We also apply the pipeline to cardiac magnetic resonance (CMR) data and electrocardiogram recordings from UK Biobank. Results We have successfully developed a pipeline for constructing biventricular volumetric models and efficiently processed biventricular coordinates (Figure). By systematically exploring interactions between ventricular regions, the model may identify critical factors contributing to arrhythmia susceptibility and guide personalised therapeutic strategies. Furthermore, the model may provide insights into the efficacy of antiarrhythmic interventions, ablation techniques, and device therapies, facilitating the development of precision medicine approaches. Conclusions We demonstrate a pipeline for constructing patient-specific biventricular computational models at scale from imaging data and apply this to LGE-MRI data and UK Biobank CMR data. These biventricular models enable investigation of the complex mechanisms of ventricular arrhythmias, providing novel insights for clinical decision-making and treatment strategies.

In-silico insights into personalised therapy selection of anti-arrhythmic drugs and ablation using patient-specific biatrial models for atrial fibrillation

Abstract Introduction Current treatment approaches for Atrial Fibrillation (AF) often lack personalisation, adopting a one-size-fits-all paradigm that disregards inter-patient diversity and its unique interplay with therapeutic responses. In-silico drug trials have demonstrated some value in the personalisation of care; however, their integration with patient-specific anatomical data and the synergistic effects of combined therapies remain unknown. Purpose To evaluate the patient-specific response to anti-arrhythmic drugs (AADs) and their efficacy both individually and in combination with pulmonary vein isolation (PVI) using personalised biatrial models created from imaging data. Methods Patient-specific biatrial models (n=70) were constructed from late gadolinium-enhanced MRI images by manual segmentation from the Atrial Segmentation Challenge (2018) dataset (Fig.1A). Models were pre-processed with landmark selection, regional assignment, and fibre allocation before simulations (Fig.1B). PVI was modelled as electrically inert rings around the pulmonary veins (Fig.1C) and AADs were administered via ionic modulation within CARPentry software (Fig.1D). Four commonly used AADs were evaluated: vernakalant, acute and chronic amiodarone, flecainide, and digoxin. Finite element simulations were performed with the addition of AADs, both individually and in combination with PVI, to evaluate their efficacy in terminating AF (Fig.2A). These simulations were post-processed to produce phase singularity (PS) density maps to evaluate changes in wavefront patterns and locations of re-entry and wavefront break-up (Fig.2B). Results The combination of digoxin with PVI and digoxin alone demonstrated the highest effectiveness in terminating AF, both achieving success in 68.4% of cases (95% CI: 67.5% to 89.3%, p≤0.0001). This efficacy significantly exceeded that of other AADs used either alone or in combination with PVI (15.8%-57.9%), whereas PVI alone demonstrated 0% efficacy (p≤0.05). The combined therapy exhibited a multi-faceted localisation pattern (Fig.2A), with AADs initially redistributing PSs to the pulmonary veins and left atrial appendage. This redistribution resulted in synergistic effects in terminating AF episodes in 52.6% more cases when combined with PVI (Fig.2B). Comparative analyses showed an inverse correlation between baseline PS density count and anatomical surface area with AF termination across all treatments, with significant correlations observed with vernakalant alone (rho=-0.55, p≤0.05) and combined with PVI (rho=-0.77, p≤0.05). Conclusions This study demonstrates the significance of personalised treatment selection in optimising patient outcomes. Combined therapeutic interventions have shown synergistic benefits in AF termination, surpassing individual therapies in this patient-specific model cohort. This shows the translational potential of using patient-specific stratification to inform treatment selection.Biatrial model generationAF therapeutic simulation and processing

Preoperative prediction of diffuse glioma type and grade in adults: a gadolinium-free MRI-based decision tree.

To develop a gadolinium-free MRI-based diagnosis prediction decision tree (DPDT) for adult-type diffuse gliomas and to assess the added value of gadolinium-based contrast agent (GBCA)enhanced images. This study included preoperative grade 2-4 adult-type diffuse gliomas (World Health Organization 2021) scanned between 2010 and 2021. The DPDT, incorporating eleven GBCA-free MRI features, was developed using 18% of the dataset based on consensus readings. Diagnosis predictions involved grade (grade 2 vs. grade 3/4) and molecular status (isocitrate dehydrogenase (IDH) and 1p/19q). GBCA-free diagnosis was predicted using DPDT, while GBCA-enhanced diagnosis included post-contrast images. The accuracy of these predictions was assessed by three raters with varying experience levels in neuroradiology using the test dataset. Agreement analyses were applied to evaluate the prediction performance/reproducibility. The test dataset included 303 patients (age (SD): 56.7 (14.2) years, female/male: 114/189, low-grade/high-grade: 54/249, IDH-mutant/wildtype: 82/221, 1p/19q-codeleted/intact: 34/269). Per-rater GBCA-free predictions achieved ≥ 0.85 (95%-CI: 0.80-0.88) accuracy for grade and ≥ 0.75 (95%-CI: 0.70-0.80) for molecular status, while GBCA-enhanced predictions reached ≥ 0.87 (95%-CI: 0.82-0.90) and ≥ 0.77 (95%-CI: 0.71-0.81), respectively. No accuracy difference was observed between GBCA-free and GBCA-enhanced predictions. Group inter-rater agreement was moderate for GBCA-free (0.56 (95%-CI: 0.46-0.66)) and substantial for GBCA-enhanced grade prediction (0.68 (95%-CI: 0.58-0.78), p = 0.008), while substantial for both GBCA-free (0.75 (95%-CI: 0.69-0.80) and GBCA-enhanced (0.77 (95%-CI: 0.71-0.82), p = 0.51) molecular status predictions. The proposed GBCA-free diagnosis prediction decision tree performed well, with GBCA-enhanced images adding little to the preoperative diagnostic accuracy of adult-type diffuse gliomas. Question Given health and environmental concerns, is there a gadolinium-free imaging protocol to preoperatively evaluate gliomas comparable to the gadolinium-enhanced standard practice? Findings The proposed gadolinium-free diagnosis prediction decision tree for adult-type diffuse gliomas performed well, and gadolinium-enhanced MRI demonstrated only limited improvement in diagnostic accuracy. Clinical relevance Even inexperienced raters effectively classified adult-type diffuse gliomas using the gadolinium-free diagnosis prediction decision tree, which, until further validation, can be used alongside gadolinium-enhanced images to respect standard practice, despite this study showing that gadolinium-enhanced images hardly improved diagnostic accuracy.

Single Nuclei Transcriptomics Reveals Obesity-Induced Endothelial and Neurovascular Dysfunction: Implications for Cognitive Decline.

Obesity confers risk for cardiovascular disease and vascular dementia. However, genomic alterations modulated by obesity in endothelial cells in the brain and their relationship to other neurovascular unit (NVU) cells are unknown. We performed single nuclei RNA sequencing (snRNAseq) of the NVU (endothelial cells, astrocytes, microglia, and neurons) from the hippocampus of obese (ob/ob) and wild-type (WT) male mice to characterize obesity-induced transcriptomic changes in a key brain memory center and assessed blood-brain barrier permeability (BBB) by gadolinium-enhanced magnetic resonance imaging (MRI). Ob/ob mice displayed obesity, hyperinsulinemia, and impaired glucose tolerance. snRNAseq profiled 14 distinct cell types and 32 clusters within the hippocampus of ob/ob and WT mice and uncovered differentially expressed genes (DEGs) in all NVU cell types, namely, 4462 in neurons, 1386 in astrocytes, 125 in endothelial cells, and 154 in microglia. Gene ontology analysis identified important biological processes such as angiogenesis in endothelial cells and synaptic trafficking in neurons. Cellular pathway analysis included focal adhesion and insulin signaling, which were common to all NVU cell types. Correlation analysis revealed significant positive correlations between endothelial cells and other NVU cell types. Differentially expressed long non-coding RNAs (lncRNAs) were observed in cells of the NVU-affecting pathways such as TNF and mTOR. BBB permeability showed a trend toward increased signal intensity in ob/ob mice. Taken together, our study provides in-depth insight into the molecular mechanisms underlying cognitive dysfunction in obesity and may have implications for therapeutic gene targeting.

Spontaneous regression of a petroclival meningioma: illustrative case.

Spontaneous regression is relatively rare in meningiomas. Since meningiomas are known to have a relationship with sex-related hormones, spontaneous regression cases related to sex hormones have been reported. A 66-year-old man with a petroclival meningioma was radiologically followed up for 13 years. The tumor initially measured 2.535 cm3 and 2.521 cm3 on gadolinium-enhanced magnetic resonance imaging (MRI) and fast imaging employing steady-state acquisition MRI, respectively. However, the measurements decreased in the follow-up period to 0.977 cm3 and 0.98 cm3, respectively, demonstrating spontaneous regression of an asymptomatic meningioma located in a petroclival area. Continuous meticulous long-term follow-up revealed this phenomenon. It is important to retain the option of conservative treatment for patients ineligible for surgery for reasons such as advanced age and coexisting diseases. https://thejns.org/doi/10.3171/CASE24416.

Unipolar voltage electroanatomic mapping detects structural atrial remodeling identified by LGE-MRI

BackgroundIn atrial fibrillation (AF) management, understanding left atrial (LA) substrate is crucial. While both electroanatomic mapping (EAM) and late gadolinium enhancement magnetic resonance imaging (LGE-MRI) are accepted methods for assessing the atrial substrate and are associated with ablation outcome, recent findings have highlighted discrepancies between low-voltage areas (LVAs) in EAM and LGE areas. ObjectiveThe purpose of this study was to explore the relationship between LGE regions and unipolar and bipolar LVAs using multipolar high-density mapping. MethodsTwenty patients scheduled for AF ablation underwent preablation LGE-MRI. LA segmentation was conducted using a deep learning approach, which subsequently generated a 3-dimensional mesh integrating the LGE data. High-density EAM was performed in sinus rhythm for each patient. The electroanatomic map and LGE-MRI mesh were coregistered. LVAs were defined using cutoffs of 0.5 mV for bipolar voltage and 2.5 mV for unipolar voltage. The correspondence between LGE areas and LVAs in the LA was analyzed using confusion matrices and performance metrics. ResultsA considerable 87.3% of LGE regions overlapped with unipolar LVAs, compared with only 16.2% overlap observed with bipolar LVAs. Across all performance metrics, unipolar LVAs outperformed bipolar LVAs in identifying LGE areas (precision: 78.6% vs 61.1%; sensitivity: 87.3% vs 16.2%; F1 score: 81.3% vs 26.0%; accuracy: 74.0% vs 35.3%). ConclusionOur findings demonstrate that unipolar LVAs strongly correlate with LGE regions. These findings support the integration of unipolar mapping alongside bipolar mapping into clinical practice. This would offer a nuanced approach to diagnose and manage AF by revealing critical insights into the complex architecture of the atrial substrate.

Use of Gadolinium-Enhanced MRI in a Patient with ADPKD and a Cyst Infection

Use of Gadolinium-Enhanced MRI in a Patient with ADPKD and a Cyst Infection

Early Bone Ischemia in Pediatric Acute Hematogenous Osteomyelitis and its Association With Progression to Chronic Osteomyelitis: New Insights From Gadolinium-enhanced Subtraction MRI.

Acute hematogenous osteomyelitis (AHO), the most common osteoarticular infection in children, carries a significant risk for chronic complications. Predicting chronic complications early in the course of disease is challenging. The underlying pathogenesis of complications is not fully understood. Children who presented to Sultan Qaboos University Hospital, Muscat, Oman between January 2015 and April 2022 for AHO were identified by a search of magnetic resonance imaging (MRI) records. Children between 1 month and 18 years of age who did not meet exclusion criteria, and whose MRI also included gadolinium-enhanced subtraction (GES) sequences were included in the analysis. Outcomes were compared between patients who showed early evidence of bone ischemia and those who did not. The analysis included 11 children who had GES MRI sequences from among 18 AHO cases in total. Median age was 5 years (IQR, 4-9), and 82% were males. Median duration of symptoms at presentation was 5 days (IQR, 3-7). GES sequences showed early bone ischemia in 6 of 11 (55%) patients. Patients with early bone ischemia were treated with significantly longer durations of IV antibiotics (median 23 vs. 10 days, P = 0.017) and oral antibiotics (median 134 vs. 29 days, P = 0.004), and required more surgical debridements (median 3 vs. 0 debridements, P = 0.017). Chronic osteomyelitis only developed among patients with early bone ischemia (5/6 vs. 0/5, P = 0.015). In pediatric AHO, GES MRI sequences revealed early bone ischemia in a significant proportion of patients. Early bone ischemia was strongly associated with progression to chronic osteomyelitis.

The relationship between endolymphatic hydrops features and hearing loss in Bilateral Meniere's disease

BackgroundThis study aimed to investigate the relationship between the features of endolymphatic hydrops and hearing loss in patients with Bilateral Meniere's Disease.MethodsA retrospective analysis was conducted on 77 patients diagnosed with Bilateral Meniere's Disease. The features of endolymphatic hydrops in the affected ear were evaluated through gadolinium-enhanced inner ear Magnetic resonance imaging. The Spearman correlation coefficient, paired t-tests, and Wilcoxon signed-rank tests were employed for data analysis.ResultsThe analysis revealed a significant correlation between the degree of endolymphatic hydrops and hearing loss across all frequencies(0.125–8 kHz), including the cochlear, vestibular, and overall degree of endolymphatic hydrops. The strongest correlation between the overall degree of endolymphatic hydrops and hearing loss was observed at low frequencies (r = 0.571, p < 0.05), followed by mid-frequencies (r = 0.508, p < 0.05), and high-frequencies (r = 0.351, p < 0.05), with a correlation of r = 0.463, p < 0.05 for the staging of Meniere's disease. Affected Ears with endolymphatic hydrops both in the cochlea and vestibule exhibited more severe hearing loss and Meniere's disease staging compared to those with isolated endolymphatic hydrops within the same patient.ConclusionsThe features of endolymphatic hydrops in patients with Bilateral Meniere's Disease were found to correlate with the severity of hearing loss and the staging of Meniere's disease.

Imaging endolymphatic space of the inner ear in vestibular migraine

BackgroundVestibular migraine (VM), the most frequent episodic vertigo, is difficult to distinguish from Ménière’s disease (MD) because reliable biomarkers are missing. The classical proof of MD was an endolymphatic hydrops...

Applications of Machine Learning in Meniere's Disease Assessment Based on Pure-Tone Audiometry.

To apply machine learning models based on air conduction thresholds of pure-tone audiometry for automatic diagnosis of Meniere's disease (MD) and prediction of endolymphatic hydrops (EH). Retrospective study. Tertiary medical center. Gadolinium-enhanced magnetic resonance imaging sequences and pure-tone audiometry data were collected. Subsequently, basic and multiple analytical features were engineered based on the air conduction thresholds of pure-tone audiometry. Later, 5 classical machine learning models were trained to diagnose MD using the engineered features. The models demonstrating excellent performance were also selected to predict EH. The model's effectiveness in MD diagnosis was compared with experienced otolaryngologists. First, the winning light gradient boosting (LGB) machine learning model trained by multiple features demonstrates a remarkable performance on the diagnosis of MD, achieving an accuracy rate of 87%, sensitivity of 83%, specificity of 90%, and a robust area under the receiver operating characteristic curve of 0.95, which compares favorably with experienced clinicians. Second, the LGB model, with an accuracy of 78% on EH prediction, outperformed the other 3 machine learning models. Finally, a feature importance analysis reveals a pivotal role of the specific pure-tone audiometry features that are essential for both MD diagnosis and EH prediction. Highlighted features include standard deviation and mean of the whole-frequency hearing, the peak of the audiogram, and hearing at low frequencies, notably at 250 Hz. An efficient machine learning model based on pure-tone audiometry features was produced to diagnose MD, which also showed the potential to predict the subtypes of EH. The innovative approach demonstrated a game-changing strategy for MD screening and promising cost-effective benefits for the health care enterprise.

Adaptive dynamic inference for few-shot left atrium segmentation

Accurate segmentation of the left atrium (LA) from late gadolinium-enhanced cardiac magnetic resonance (LGE CMR) images is crucial for aiding the treatment of patients with atrial fibrillation. Few-shot learning holds significant potential for achieving accurate LA segmentation with low demand on high-cost labeled LGE CMR data and fast generalization across different centers. However, accurate LA segmentation with few-shot learning is a challenging task due to the low-intensity contrast between the LA and other neighboring organs in LGE CMR images. To address this issue, we propose an Adaptive Dynamic Inference Network (ADINet) that explicitly models the differences between the foreground and background. Specifically, ADINet leverages dynamic collaborative inference (DCI) and dynamic reverse inference (DRI) to adaptively allocate semantic-aware and spatial-specific convolution weights and indication information. These allocations are conditioned on the support foreground and background knowledge, utilizing pixel-wise correlations, for different spatial positions of query images. The convolution weights adapt to different visual patterns based on spatial positions, enabling effective encoding of differences between foreground and background regions. Meanwhile, the indication information adapts to the background visual pattern to reversely decode foreground LA regions, leveraging their spatial complementarity. To promote the learning of ADINet, we propose hierarchical supervision, which enforces spatial consistency and differences between the background and foreground regions through pixel-wise semantic supervision and pixel-pixel correlation supervision. We demonstrated the performance of ADINet on three LGE CMR datasets from different centers. Compared to state-of-the-art methods with ten available samples, ADINet yielded better segmentation performance in terms of four metrics.

Normative Measurements of the Infraorbital Nerve by Magnetic Resonance Imaging in an Australia Cohort.

To report the normative dimensions of the infraorbital nerve on fat-suppressed gadolinium-enhanced MRI and correlate with patient demographics in an Australian cohort. A retrospective review of patients who underwent coronal fat-suppressed gadolinium T1-weighted MRI from September 2021 to December 2023. One hundred sixty-eight orbits were included. The maximum diameter of the infraorbital nerve and the optic nerve sheath was measured. Orbits were excluded if there was unilateral or bilateral pathology of the infraorbital nerve or optic nerve sheath, incomplete MRI sequences, poor image quality, or indiscernible infraorbital nerve on radiological examination. The mean age of participants was 58 ± 16 years, and 50% were females (n = 42). The mean normative measurements (mean ± standard deviation) on coronal T1-weighted imaging: optic nerve sheath, 5.08 ± 0.67 mm. On coronal fat-suppressed gadolinium T1-weighted imaging: infraorbital nerve, 0.89 ± 0.22mm. No significant differences were found between male or female participants in both the infraorbital nerve (p = 0.757) or optic nerve sheath (p = 0.646). There was no significant correlation between age and mean diameter of the infraorbital nerve (r = 0.077, p = 0.320) or optic nerve sheath (r = 0.075, p = 0.336). Additionally, no significant difference was identified between the mean diameter of the infraorbital nerve (p = 0.079) and optic nerve sheath (p = 0.120) across age groups. The mean infraorbital nerve to optic nerve sheath ratio was 0.18 ± 0.00. Normative dimensions of the infraorbital nerve may be used to identify enlargement in conditions such as IgG4-related ophthalmic disease and reactive lymphoid hyperplasia.

DELAYED GADOLINIUM-ENHACED MAGNETIC RESONANCE IMAGING OF CARTILAGE IS A PREDICTOR OF PERIACETABULAR OSTEOTOMY FAILURE IN PATIENTS 40 YEARS AND OLDER

Pelvic osteotomies for hip dysplasia results can be variable and depend on the amount of preexisting arthritis. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a technique designed to measure early arthritis, and could be used to select hips that would benefit from a joint-preserving reconstructive procedure. Our objective was to investigate the role of preoperative dGEMRIC in predicting the success of PAO in patients 40 and above. We hypothesized that patients who failed had lower preoperative dGEMRIC index compared to those who did not.Following IRB approval, patients 40 or older who underwent PAO between 1990–2013 and had preoperative dGEMRIC scan and minimum follow-up of 4 years were identified. Patients with prior hip surgeries or any pathologies were removed leading to a total of 70 patients (Age: 44.2 ± 2.9 years old, BMI: 25.7 ± 4.5 Kg/m2). We only included the first hip undergoing PAO for those with bilateral PAO. Out of 70, 19 had failure defined by the need for total hip replacement or WOMAC pain score of 10 and above within 10 years after index PAO surgery. Articular cartilage was segmented on the 3D pre-operative dGEMRIC scan. The average thickness and dGEMRIC index across the whole articular surface were analyzed.Failed hips had a lower dGEMRIC index by 115 ± 20 ms (P&lt;0.001). All but one failed hips had a dGMERIC index of 400 or less (range: 313 – 479 ms), while all survived hips had a dGMERIC index of greater than 400 (range: 403 – 691 ms). Similar trends were observed when comparing the dGEMRIC index within the 6 subgroups (P&lt;0.01). There were no differences in cartilage thickness (combined femoral head and acetabular cartilage) between the failed and survived hips (p&gt;0.2).Patients with a high dGMERIC index (indicating high GAG content) may have a higher chance of successful outcomes following PAO. Current efforts are underway to develop a multi-modal predictive model to evaluate risk of failure after PAO.

The Feasibility of a Model-Based Iterative Reconstruction Technique Tuned for the Myocardium on Myocardial Computed Tomography Late Enhancement.

This study evaluated the feasibility of a model-based iterative reconstruction technique (MBIR) tuned for the myocardium on myocardial computed tomography late enhancement (CT-LE). Twenty-eight patients who underwent myocardial CT-LE and late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) within 1 year were retrospectively enrolled. Myocardial CT-LE was performed using a 320-row CT with low tube voltage (80 kVp). Myocardial CT-LE images were scanned 7 min after CT angiography (CTA) without additional contrast medium. All myocardial CT-LE images were reconstructed with hybrid iterative reconstruction (HIR), conventional MBIR (MBIR_cardiac), and new MBIR tuned for the myocardium (MBIR_myo). Qualitative (5-grade scale) scores and quantitative parameters (signal-to-noise ratio [SNR] and contrast-to-noise ratio [CNR]) were assessed as image quality. The sensitivity, specificity, and accuracy of myocardial CT-LE were evaluated at the segment level using an American Heart Association (AHA) 16-segment model, with LGE-MRI as a reference standard. These results were compared among the different CT image reconstructions. In 28 patients with 448 segments, 160 segments were diagnosed with positive by LGE-MRI. In the qualitative assessment of myocardial CT-LE, the mean image quality scores were 2.9 ± 1.2 for HIR, 3.0 ± 1.1 for MBIR_cardiac, and 4.0 ± 1.0 for MBIR_myo. MBIR_myo showed a significantly higher score than HIR (P < 0.001) and MBIR_cardiac (P = 0.018). In the quantitative image quality assessment of myocardial CT-LE, the median image SNR was 10.3 (9.1-11.1) for HIR, 10.8 (9.8-12.1) for MBIR_cardiac, and 16.8 (15.7-18.4) for MBIR_myo. The median image CNR was 3.7 (3.0-4.6) for HIR, 3.8 (3.2-5.1) for MBIR_cardiac, and 6.4 (5.0-7.7) for MBIR_myo. MBIR_myo significantly improved the SNR and CNR of CT-LE compared to HIR and MBIR_cardiac (P < 0.001). The sensitivity, specificity, and accuracy for the detection of myocardial CT-LE were 70%, 92%, and 84% for HIR; 71%, 92%, and 85% for MBIR_cardiac; and 84%, 92%, and 89% for MBIR_myo, respectively. MBIR_myo showed significantly higher image quality, sensitivity, and accuracy than the others (P < 0.05). MBIR tuned for myocardium improved image quality and diagnostic performance for myocardial CT-LE assessment.

Abstract Mo040: Enhanced neovascularisation does not account for preservation of cardiac function by 11βHSD1 inhibition in a pig model of myocardial infarction

While acute post-myocardial infarction (MI) survival has improved thanks to early intervention, the myocardium still sustains damage that increases the risk of heart failure. Adrenal glucocorticoids (GCs) protect cardiomyocytes immediately after MI, but inhibition of GC regeneration within the heart by 11β-hydroxysteroid dehydrogenase 1 (11βHSD1) during infarct repair prevents subsequent deterioration of ventricular structure and function. In the 11βHSD1-knockout mouse this outcome is associated with enhancement of peri-infarct neovascularisation and prevention of infarct expansion. Here, we tested the hypothesis that pharmacological 11βHSD1 inhibition after MI can preserve function in a translational pig model and investigated the role of neovascularisation. MI was induced in female minipigs via temporary coronary occlusion. A standard clinical therapy (SCT, n =9) group received statin, anti-platelet, βadrenoreceptor antagonist and ACE inhibitor immediatley after MI, and a 11βHSD1i group (n=11) received SCT +11βHSD1 inhibitor (50mg/kg) from 48h after MI until the end of the study. Prior to 11βHSD1i treatment, short-axis cine and late gadolinium-enhanced MRI showed no difference in either infarct mass (4.2±0.4g SCT vs 4.0±0.6g 11βHSD1i) or ejection fraction (EF; 60.6±2.9% SCT vs 56.6±1.8% 11βHSD1i). However, by 28 days after MI, while EF was reduced in SCT pigs to 48±4%, it was maintained in pigs given additional 11βHSD1i treatment (57.9±1.8%, p &lt;0.05 vs SCT). Infarct mass did not differ between the two treatments, suggesting that inhibition of infarct expansion did not account for the improvement in function, this was confirmed by a similar area of infarct collagen in histological analysis. Angiogenesis, represented by an increase in CD31 +ve capillaries, was not enhanced in the infarct or the border zone (BZ) after 11βHSD1i treatment, relative to SCT. While vessel maturation (αSMA +ve vessels) was improved in the infarct compared to the remote myocardium, there was no difference between the two groups. Proteomic pathway analysis of the BZ indicated extracellular matrix organisation as the main pathway regulated by 11βHSD1i compared to SCT. In conclusion, 11βHSD1i after MI successfully preserves cardiac function and structure but the mechanism is independent of scar size reduction or enhanced neovascularisation. Instead, the beneficial effects of 11βHSD1i are likely to result from favourable regulation of collagen processing during scar formation.

Hearing, balance, and imaging assessment in adolescent Menière's disease: A retrospective analysis.

To retrospectively analyze clinical features in adolescent Menière's disease (MD). The medical records of adolescents with MD (11-17 years old) from May 2014 to March 2023 in Shandong Provincial ENT Hospital were retrospectively analyzed, including clinical features, a battery of auditory and vestibular function tests, sensory organization test, and imaging assessments. Patients with recurrent vertigo of childhood (RVC) were as controls. Compared with RVC, adolescent MD showed higher pure tone average threshold (p < .001), lower speech discrimination score (p = .014), and lower otoacoustic emission pass rates (p = .005). Adolescents with MD exhibited significant reduction in equilibrium score (Conditions 1, 5, and 6; p1 = .035; p5 = .033; p6 = .003), composite sensory score (p = .014), and vestibular sensory score (p = .029). Adolescents with bilateral MD exhibited worse performance in equilibrium score and strategy score compared to adolescents with unilateral MD. For the affected ear, the more severe endolymphatic hydrops detected by gadolinium-enhanced magnetic resonance imaging, the higher the auditory brainstem response threshold (r = .850, p = .007), and the lower the otoacoustic emission pass rate (r = -.976, p < .001). Adolescent MD has similar vestibular information inputs with that of RVC, but the ability for the nerve center to use these clues to maintain balance is worse in adolescents with MD. There were potential differences in vestibular weights in adolescents with unilateral and bilateral MD, also potential effects on vision and proprioception. Level 4.

Clinical and Radiologic Follow-Up in Ecchordosis Physaliphora: A Case Series and Literature Review

This study endeavors to assess the clinical and radiologic findings of Ecchordosis physaliphora (EP) in patients under long-term observation at our clinic, as well as in cases reviewed from the existing literature. In our study, we evaluated EP lesions in a total of 16 patients, who underwent follow-up and treatment in the neurosurgical unit. We conducted a retrospective review using magnetic resonance imaging (MRI) and computed tomography (CT) studies to confirm the diagnoses as EP. We conducted a systematic literature review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, encompassing a database search from inception to January 2024. We included confirmed cases of EP from both surgically and conservatively reported studies. Our study included a total of 16 patients, consisting of 9 (56.25%) men and 7 (43.75%) women, with an average age of 45±17.3 years. Among them, 7 (43.75%) patients presented with headaches, while 3 (18.75%) reported hearing loss. Incidental EP was detected in 6 (37.5%) patients in the study during imaging performed for different indications. The key radiological features of EP comprised hypointensity on T1, hyperintensity on T2, and an absence of MRI gadolinium enhancement. In one out of the sixteen cases, we employed an endoscopic endonasal approach for resection, and there was no recurrence observed over an average postoperative follow-up period of 24 months. Among the 15 patients, who underwent conservative follow-up, 12 (80%) had the classical Type B EP, one (10%) patient exhibited BNCT in the C2 vertebra, and another (10%) patient presented with a variant type EP. Utilizing a combination of imaging modalities, ensuring a clear radiological distinction between EP and chordoma, can offer substantial advantages in this context. Given that EP might be incidentally discovered, and non-resistant symptoms may resolve on their own, considering conservative treatment before surgery may be a viable option in all cases.