Advanced Imaging Research Articles

Consent to advanced imaging in antenatal pulmonary embolism diagnostics: Prevalence, outcomes of nonconsent and opportunities to mitigate delayed diagnosis risk

AbstractBackgroundNonconsent to pulmonary vascular (or advanced) imaging for suspected pulmonary embolism (PE) in pregnancy can delay diagnosis and treatment, increasing risk of adverse outcomes. We sought to understand factors associated with consent and understand outcomes after nonconsent.MethodsThis retrospective cohort study was undertaken across 21 community hospitals from October 1, 2021, through March 31, 2023. We included gravid patients undergoing diagnostics for suspected PE who were recommended advanced imaging. The primary outcome was verbal consent to advanced imaging. Diagnostic settings were nonobstetric (99% emergency departments [EDs]) and obstetrics (labor and delivery and outpatient clinics). Using quasi‐Poisson regression, we calculated adjusted relative risks (aRRs) of consenting with 95% confidence intervals (CIs). We also reported symptom resolution and delayed imaging at follow‐up and 90‐day PE outcomes.ResultsImaging was recommended for 405 outpatients: median age was 30.5 years; 50% were in the third trimester. Evaluation was more common in nonobstetric (83%) than obstetric settings (17%). Overall, 314 (78%) agreed to imaging and 91 (22%) declined imaging. Consenting was more prevalent in obstetric settings compared with nonobstetric settings: 99% versus 73% (p < 0.001). When adjusted for demographic and clinical variables, including pretest probability, only obstetric setting was independently associated with consenting: aRR 1.26 (95% CI 1.09–1.44). Seventy‐nine (87%) patients declining imaging had 30‐day follow‐up. Eight of 12 who reported persistent or worsening symptoms on follow‐up were again recommended advanced imaging and consented. Imaging was negative. None who initially declined imaging were diagnosed with PE or died within 90 days.ConclusionsOne in five gravid patients suspected of PE declined advanced imaging, more commonly in nonobstetric (principally ED) settings than obstetric settings. Patients symptomatic on follow‐up responded favorably to subsequent imaging recommendations without 90‐day outcomes. Improving the communication and documentation of informed consent and securing close follow‐up for nonconsenters may mitigate risks of missed and delayed PE diagnosis.

Abstract PR014: DNA associated with EVs is uniquely chromatinized and prevents metastasis by enhancing anti-tumor immunity

Abstract Cells release extracellular vesicles (EVs) loaded with functional biomolecules that facilitate intercellular communication in health and disease. These EVs contain DNA (EV-DNA), mirroring the mutational profile of parental cells, yet the mechanism of DNA packaging onto EVs and its role in diseases like cancer remain unclear. Using advanced imaging and biochemical techniques, we discovered that EV-DNA predominantly resides on the vesicle surface, bound to modified histones. Through genome-wide CRISPR knockout screens in cancer cell lines, we identified immune-related pathways and genes crucial for EV-DNA loading, such as APAF1 and NCF1. In several cancer models, loss of APAF1 reduced EV-DNA packaging, and enhancing metastasis, thus implicating EV-DNA in immune surveillance against cancer spread. We demonstrated that EV-DNA uptake by liver macrophages triggers DNA damage response, altering cytokine production and promoting immune activation in pre-metastatic sites. Moreover, quantifying EV-DNA in colorectal cancer biopsies revealed its potential as a predictive metastatic risk biomarker. Our findings shed light on EV-DNA packaging mechanisms and its significance, suggesting that elevated levels of tumor-derived EV-DNA bolster anti-tumor immunity and inhibit metastasis. Citation Format: Inbal Wortzel, Han-Sang Kim, David C. Lyden. DNA associated with EVs is uniquely chromatinized and prevents metastasis by enhancing anti-tumor immunity [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr PR014.

Metasurfaces‐Enabled Advanced Multidimensional Imaging: Principle and Applications

AbstractThe efficient acquisition of multidimensional information—spatial, polarization, frequency, and phase of optical fields, is a key research focus. Metasurfaces, which are emerging as planar arrays of artificial nanostructures, offer significant advantages in advanced imaging due to their exceptional ability to manipulate electromagnetic waves through subwavelength optical resonators. Meanwhile, the rapidly developing computational imaging algorithms have also greatly enhanced the performance of metasurfaces in multi‐dimensional imaging. In this review, we focus on the research progress in metasurface‐empowered multidimensional imaging, including advanced spatial imaging, compact polarization imaging, high‐resolution spectral imaging, single‐shot phase imaging, and edge imaging. Their basic principles and imaging results will also be presented. Furthermore, a summary of several current challenges and anticipation in various future directions within this field will also be provided.

Open-chest cardiac ultrasound-mediated imaging with a vacuum coupler.

A fundamental obstacle for the preclinical development of ultrasound-(US) mediated cardiac imaging remains cardiac motion, which limits interframe correlation during extended acquisition periods. To address this need, we present the design and implementation of a 3D-printed vacuum coupler that stabilizes a US transducer on the epicardial surface of the heart for feasibility assessment and development of advanced, cardiac, US-mediated imaging approaches. The vacuum coupler was 3D printed with biocompatible resins and secured with a standard intraoperative suction aspirator. US-mediated imaging (i.e., B-mode and photoacoustic [PA] imaging) was performed in an open-chest porcine model with and without the vacuum coupler. Based on inter-frame displacement tracking and cross-correlation (CC) coefficients, changes in frame motion and stability were compared for each imaging mode/configuration through a prolonged (∼1min) acquisition, while the impact on PA-based SO2 accuracy was assessed. When compared to conventional handheld imaging, stand-off imaging, and coupler without suction, epicardial imaging with the vacuum coupler and suction applied led to a significantly reduced mean axial displacement of 0.15 mm versus 0.89, 0.49, & 0.49 mm, respectively (p-values≤8.65e-7). Comparing the coupler without suction to that with suction applied, physiologically unrealistic SO2 estimates reduced from 1.72 to 0.81%, respectively, and lateral interframe displacement reduced from 4.58 to 2.01mm, respectively (p-value=5.07e-23). Overall,reduced cardiac tissue motion and increased interframe CC coefficient (baseline=0.43vs. coupler with suction=0.80) allow for more accurate PA unmixing. Epicardial US-mediated imaging with a vacuum coupler reduces cardiac motion artifact, providing a consistent sampling of an intended region of interest (ROI) over multiple cardiac cycles. This could help facilitate the development of advanced US-mediated imaging, which is often hindered by cardiac motion. Stable implementation of these imaging techniques could allow for intra-operative assessments of local cardiac perfusion as well as tissue characterization.

Guidance for Canadian Breast Cancer Practice: National Consensus Recommendations for Clinical Staging of Patients Newly Diagnosed with Breast Cancer

The accurate staging of breast cancer is fundamental for guiding treatment decisions and predicting patient outcomes. However, there can be considerable variation in routine clinical practice based on individual interpretation of guidelines and depending on the healthcare provider initially involved in working up patients newly diagnosed with breast cancer, ranging from primary care providers, triage nurses, surgeons, and/or oncologists. The optimal approach for clinical staging, particularly in asymptomatic patients presenting with intermediate-risk disease, remains a topic of dialogue among clinicians. Given this area of uncertainty, the Research Excellence, Active Leadership (REAL) Canadian Breast Cancer Alliance conducted a modified Delphi process to assess the level of agreement among Canadian expert clinicians on various staging recommendations. In total, 20 items were drafted covering staging based on biological status, the utilization of localization clips, both for the axilla during diagnosis and primary surgical site for margins and radiation therapy planning, and the use of advanced imaging for the investigation of distant metastases. Overall, the consensus threshold among all participants (i.e., ≥75% agreement) was reached in 20/20 items. Differences in clinical practice and recent findings from the literature are provided in the discussion. These consensus recommendations are meant to help standardize breast cancer staging practices in Canada, ensuring accurate diagnosis and optimal treatment planning.

Rare Cause of Pediatric Abdominal Pain Diagnosed on Point of Care Ultrasound (POCUS)

An 11-year-old postmenarchal female presented to the pediatric emergency department (ED) with 2 days of periumbilical and right lower abdominal pain. Radiology-performed ultrasound (RADUS) did not visualize the appendix, and there was a plan for surgical consultation to decide between serial abdominal exams versus computed tomography (CT) scan. While awaiting consultation and to help further narrow the differential diagnosis, the emergency provider performed a point of care ultrasound (POCUS) of the urinary tract. This revealed several anomalies including a solitary left kidney with hydronephrosis, and a well-circumscribed, fluid-filled structure with mixed echogenicity posterior to the bladder and inferior to the uterus. Given these findings on POCUS, further imaging was pursued, including a RADUS of the pelvis followed by a magnetic resonance imaging (MRI) of the abdomen. Further imaging ultimately diagnosed a bicornuate uterus, septate vagina with hematocolpos and solitary left kidney consistent with Obstructed Hemivagina and Ipsilateral Renal Anomaly (OHVIRA) syndrome. This case is an illustration of how POCUS is an invaluable tool to narrow the differential diagnosis and guide advanced imaging or consultation for both common and rare causes of pediatric abdominal pain.

Effects of age on accuracy of advanced imaging modalities in identifying intervertebral disc extrusions in Dachshunds.

The aim of this study was to ascertain whether patient age was a significant factor for the accurate identification of compressive intervertebral disc extrusions (IVDE) in Dachshunds using non-contrast computed tomography (CT). This retrospective analysis encompassed 150 Dachshunds evaluated for suspected IVDE at a referral hospital in south-eastern Queensland, Australia. Each case underwent diagnostic evaluation by CT, either with or without myelography, or magnetic resonance imaging (MRI), followed by surgical intervention for an intervertebral disc extrusion. In the <9-year dog cohort, 94.7% (71/75) were diagnosed with IVDE via non-contrast CT and proceeded to surgery. In contrast, the ≥9-year dog cohort, only 56% (42/75) were diagnosed via non-contrast CT, with the remaining 44% (33/75) necessitating CT myelography or MRI for diagnosis. The odds of requiring CT myelography or MRI increased 13.95-fold (95% CI, 4.62-42.13) in Dachshunds aged 9 years or older. Furthermore, each additional year of age was associated with a 0.60 increase in the odds of undergoing these advanced imaging modalities (CT myelography or MRI) (95% CI, 0.49-0.74). Age significantly affected the efficacy of non-contrast CT in diagnosing IVDE in Dachshunds. Dogs aged 9 years and above were substantially more likely to require CT myelography or MRI due to the reduced visibility of disc extrusions on non-contrast CT. Veterinarians performing advanced imaging on older Dachshunds for suspected IVDE should be aware of the limitations of non-contrast CT in obtaining an accurate diagnosis and localisation of IVDE, and be prepared to perform either CT myelography or MRI if required.

Diagnostic power of serum creatinine/cystatin C ratio for identifying low MRI-muscle volume and low grip strength: Data from 9,731 to 149,707 UK Biobank older adults.

Biomarkers for sarcopenia are lacking. We examined the diagnostic power of serum creatinine to cystatin C (Cr:Cyc) ratio for identifying low MRI-muscle volume and low grip strength in a large observational study of UK Biobank older adults. Serum creatinine and cystatin C were measured via immunoassays (Beckman Coulter AU5800 and Siemens Advia 1800, respectively) and grip strength by hydraulic hand dynamometer at baseline visit (2008-2010). MRI-thigh fat-free muscle volume (FFMV) and DXA-derived appendicular lean mass were measured at imaging visit (2014-2018). Extreme outliers were removed, and covariates (demographic, lifestyle, and clinical factors, as well as time elapsed between baseline-imaging visit) were adjusted for in statistical models. 12,873 older adults (mean age: 63.5 ± 2.7 years, 44.2% women) were included for FFMV and ALM/BMI; 149,707 older adults (mean age: 64.0 ± 2.9 years, 50.5% women) for grip strength. Despite significant associations (p<0.05), in fully-adjusted models, Cr:Cyc showed poor to acceptable diagnostic power for identifying low FFMV when using cutpoints of 20th percentile (AUC: 0.577 men; 0.622 women) and T scores of -2 (AUC: 0.596 men; 0.659 women) and -2.5 (AUC: 0.609 men; 0.722 women). In fully-adjusted model, Cr:Cyc showed poor diagnostic power (AUCs: <0.70) for identifying low ALM/BMI or low grip strength irrespective of the cutpoint used. Cr:Cyc may not be a suitable biomarker for identifying low muscle volume or low strength in older adults. This finding, drawn from a large sample size and the use of advanced medical imaging, marks an important contribution to the sarcopenia field.

SURGICAL RESECTION OF A COMPLEX TUBERCULUM SELLAE MENINGIOMA ENCASING MAJOR ARTERIES

Introduction Though constituting only a minor proportion (1%) of sellar masses, suprasellar meningiomas pose a significant diagnostic challenge within the region of sellar and suprasellar tumors. Pituitary adenomas, at nearly 90% prevalence, dominate this anatomical region. Distinguishing these two entities is paramount, as both clinical presentation and, to some extent, biochemical profiles exhibit notable overlap. Accurate preoperative differentiation is critical due to the contrasting behaviors of these tumors. Meningiomas, with their robust vascularity supplied by dural and osseous arteries, present a heightened risk of intraoperative hemorrhage. Clinical Case A 53-year-old woman presented with a two-month history of worsening headaches and gradual vision loss. Neurological examination revealed only visual acuity decline. Her hormone profile showed elevated prolactin but lacked clinical features of prolactin excess, suggesting a possible prolactin-secreting pituitary macroadenoma. A contrast-enhanced MRI confirmed a significant sellar and suprasellar mass with homogeneous enhancement, extending to the right paramedian region and encasing the right internal carotid artery (ICA) at its critical segment involving the cavernous and supraclinoid portions. Furthermore, the right middle meningeal artery (M1) and anterior cerebral artery (A1) originated from this same location, highlighting the high surgical risk. Surgical resection was deemed necessary. The patient underwent a right pterional craniotomy, revealing a grayish, extradural soft mass lesion encasing the ICA bifurcation. Careful microsurgical dissection with basal devascularization was performed, followed by near-complete tumor removal using an ultrasonic aspirator to minimize damage to the encased arteries. Postoperative follow-up CT scan confirmed successful near-total tumor ablation. Conclusion This case underscores the critical role of meticulous preoperative diagnosis in managing complex sellar tumors. While pituitary adenomas dominate this region, suprasellar meningiomas, despite their rarity, demand a high index of suspicion. Overlapping clinical and biochemical presentations highlight the reliance on advanced imaging for accurate differentiation. The intricate vascularity of meningiomas, as exemplified by the encasement of critical arteries in this case, necessitates meticulous surgical technique with devascularization strategies. This successful near-complete tumor removal emphasizes the importance of such surgical expertise in navigating these diagnostically challenging sellar lesions.

Anterior Glenohumeral Instability

➢ Anterior glenohumeral instability is a complex orthopaedic problem that requires a detailed history, a thorough physical examination, and a meticulous review of advanced imaging in order to make individualized treatment decisions and optimize patient outcomes.➢ Nonoperative management of primary instability events can be considered in low-demand patients, including elderly individuals or younger, recreational athletes not participating in high-risk activities, and select in-season athletes. Recurrence can result in increased severity of soft-tissue and osseous damage, further increasing the complexity of subsequent surgical management.➢ Surgical stabilization following primary anterior instability is recommended in young athletes who have additional risk factors for failure, including participation in high-risk sports, hyperlaxity, and presence of bipolar bone loss, defined as the presence of both glenoid (anteroinferior glenoid) and humeral head (Hill-Sachs deformity) bone loss.➢ Several surgical treatment options exist, including arthroscopic Bankart repair with or without additional procedures such as remplissage, open Bankart repair, and osseous restoration procedures, including the Latarjet procedure.➢ Favorable results can be expected following arthroscopic Bankart repair with minimal (&lt;13.5%) bone loss and on-track Hill-Sachs lesions following a primary instability event. However, adjunct procedures such as remplissage should be performed for off-track lesions and should be considered in the setting of subcritical glenoid bone loss, select high-risk patients, and near-track lesions.➢ Bone-grafting of anterior glenoid defects, including autograft and allograft options, should be considered in cases with &gt;20% glenoid bone loss.

VS 09 - HPB Laparoscopic Trans-Cystic Bile Duct Exploration is Safe and Feasible even after previous Cholecystectomy

Abstract Background Laparoscopic trans-cystic bile duct exploration is well know to have less comorbidity that conventional trans-ductal approach. A 56-year-old female underwent emergency laparoscopic cholecystectomy in 2019 for cholecystitis. Subsequently treated conservatively for ascending cholangitis due to large stone in the bile duct on MRCP. She underwent two unsuccessful ERCPs due to anatomical challenges; large hiatus hernia and duodenal diverticulum. The MDT determined bile duct exploration was necessary as no endoscopic options remained. After assessing previous imaging, laparoscopic trans-cystic exploration was chosen to minimise complications. This video highlights the feasibility of laparoscopic trans-cystic CBD post-cholecystectomy. Method Standard four-port technique with 10mm, 30-degree laparoscope. Blunt, sharp, energised and hydro-dissection were employed. Indocyanaine green(ICG) helped identify the bile duct(CBD) and the cystic duct(CD) stump. CD was dissected from the gallbladder bed and opened for a cholangiogram; confirming a large stone in the distal bile duct. A 3.5 mm choledochoscope with electrohydraulic lithotripsy(EHL) was used to explore the bile duct and fragment the stone for extraction. Remaining small fragments were flushed into the duodenum after 20mg buscopan intravenously. Final cholangioscopy and cholangiogram through the choledochoscope showed clear ducts with good flow into the duodenum. Results The patient was started on IV antibiotics due to pyrexia on the first night of admission. The abdominal drain was removed after 48 hours, and the patient was discharged on day three to complete a five-day course of antibiotics. Nine months post-operatively, she presented with a 3x5x7.5 cm sub-hepatic abscess, requiring interventional radiology (IR) drainage and a six-week course of antibiotics. The drain was removed after a follow-up CT scan three weeks post-drainage showed resolution. There have been no further episodes of cholangitis, and she has returned to her baseline quality of life. Conclusion This case shows laparoscopic trans-cystic approach remains viable post-cholecystectomy. Advanced imaging and tools including 3.5mm choledochoscope and EHL aid safer surgery with reduced morbidity, shorter stays and faster recovery. Antibiotics may be necessary for cases with longstanding bile duct stones. Furthermore, this case highlights the importance of intraoperative cholangiography and bile duct exploration. The patient had an MRCP in 2019 that showed no bile duct stones but a dilated CBD associated with deranged LFTs. This suggests that her journey might have been less complicated if a cholangiogram had been performed during the initial laparoscopic cholecystectomy.

Craniofacial Injuries Resulting from Polytrauma: Mechanisms, Imaging, and Complications

Purpose: This literature review aims to identify and analyse the most common mechanisms causing injuries in the craniofacial region their diagnosis and possible sequelae. Methods: The study analysed publications from the Medline database made available in PubMed and Google Scholar considering the following keywords "maxillofacial injuries" and/or "maxillofacial trauma" and/or "maxillofacial fractures". Results: Craniofacial injuries in polytrauma patients are often complicated by their heterogeneous nature and coexistence with other injuries. Their incidence and mechanisms vary depending on the country of investigation. Diagnosis includes advanced imaging techniques such as CT scans. Treatment often requires multidisciplinary collaboration. Conclusions: Craniofacial injuries in polytraumatic patients require a complex diagnostic and therapeutic approach. Interdisciplinary collaboration is crucial to achieve the best clinical outcome. The most common causes include road traffic collisions, assaults, falls and sports-related injuries. Despite properly applied treatment protocols, they generate changes in the stomatognathic system, sensory disturbances, blindness and, in extreme cases, can lead to death

Abstract 4138345: Incidence and Predictors of Infective Endocarditis in Bacteremic Patients

Background: Infective endocarditis (IE) is a serious disease, with a high mortality rate.There has been a shift in the composition of organisms causing infective endocarditis. We aimed to provide a contemporary incidence of IE among bacteremic patients stratified by bacterial pathogens. We also sought to evaluate the predictors of IE in bacteremic patients. Methods: We included patients at a large quaternary centre in Canada. All bacteremias during the period from 2014 to 2016 were identified and data was collected on the following variables – patient demographics, organism, comorbidities, pre-disposing factors, clinical findings, pertinent biochemistry, performance of echocardiography, and diagnosis of IE. Diagnosis of IE was made using the modified Duke’s criteria. Logistic regression was used to identify predictors of IE. Results: There were 1,708 patients with bacteremia included in this analysis. The mean age was 64.5±17.0 years old; 39.7% were females and 77.4% were community acquired bacteremia. In addition, 47.0% had hypertension, 29.9% had diabetes mellitus, 17.5% had chronic kidney disease and 25.2% were immunosuppressed. There were 102 (6.0%) patients with confirmed infective endocarditis (IE). The proportion of bacteremic patients who developed IE was 13.2% in 281 patients with methicillin-sensitive Staphylococcus aureus, 5.4% in 56 patients with methicillin-resistant S. aureus, 2.4% in 292 patients with S. epidermidis, 9.9% in 121 patients with Streptococcus viridans group, 16.5% in 91 patients with Enterococcus, 1.3% in 303 patients with Escherichia coli, 38.5% in 13 in patients with Streptococcus bovis, and 9.5% in 21 patients with Propionibacterium acnes. Predictors of IE were intravenous drug use (odds ratio [OR]=8.64, 95% confidence interval [CI] 3.50- 21.3; p&lt;0.0001), prosthetic heart valve (OR= 2.10, 95% CI 1.01- 4.39; p=0.049), structural heart disease (OR= 12.2, 95% CI 3.35- 44.67; p= 0.0002) and community acquired bacteremia (OR= 2.06, 95% CI 1.11- 3.82; p=0.02). CONCLUSIONS: Methicillin-sensitive Staphylococcus aureus is the commonest cause overall of IE followed by viridans group streptococcus. Streptococcus bovis and Enterococcus bacteremia have the highest incidence of IE. Knowledge of the incidence rates of IE among various pathogens may guide diagnostic testing such as pursuing more advanced imaging procedures for patients with increased risk of IE.

BIOM-54. AI-DRIVEN RISK-OF-PROGRESSION (AIRIP) CLASSIFIER FOR DISTINGUISHING RECURRENT BRAIN METASTASES FROM RADIATION TREATMENT EFFECT: A MULTI-INSTITUTIONAL COMPARATIVE STUDY WITH ADVANCED MULTIMODAL IMAGING

Abstract Following radiation therapy, a significant challenge in brain metastases (BM) management is differentiating radiation-induced-treatment effect (TrE) from tumor recurrence (TuR). TrE can be indistinguishable from TuR using conventional MRI. Advanced imaging techniques (e.g., perfusion MRI, PET/MRI) are not consistently used, and the standardized Response Assessment in Neuro-Oncology for brain metastases (RANO-BM) is sensitive to inter-reader variability. The performance of an artificial intelligence (AI)-driven risk-of-progression (AiRiP) classifier, which has been shown to capture pathophysiologic differences between TrE and TuR on routine MRI, was compared to that of clinical assessments and advanced imaging methods, in a multi-institutional setting. A total of n=261 lesions with pathologically-confirmed diagnoses in n=189 patients were analyzed. 115 lesions (73 TuR, 42 TrE) from site 1, 86 lesions (38 TuR, 48 TrE) from site 2, and 60 lesions (33 TuR, 27 TrE) from site 3 were used for training and testing the AiRiP-model. Gd-T1w, T2w, FLAIR MRI were preprocessed, and lesions were segmented by experts. Texture features (n=856) were extracted from each lesion. Random-forest classifier was employed for 3-fold cross-validation. Top-performing AiRiP-features, RANO-BM criteria, perfusion MRI and PET/MRI were evaluated in a sub-group analysis. For n=51 lesions on the test-set (site 3), 14 were classified as stable disease and 37 as TuR using RANO-BM (accuracy=54.1%). AiRiP-model achieved an accuracy of 76.5% on the same test-set and accurately classified 78.6% of the stable lesions as TrE or TuR. For another subset of lesions (n=27) on the same test-set, perfusion MRI and AiRiP-model achieved an accuracy of 59.3% and 70.4%, respectively. Lastly, for a subset of lesions (n=35) on the test-set (site 2), multimodal (perfusion, PET) imaging and AiRiP-model accurately classified 60% and 74.3% of lesions, respectively. 15 lesions were considered indeterminate via multimodal imaging, 73.3% of which AiRiP-model accurately classified as TrE or TuR. Our results suggest AI-driven models on conventional MRI may reliably distinguish TuR from TrE.

RADT-46. RADIOSURGERY DOSE REDUCTION FOR BRAIN METASTASES ON IMMUNOTHERAPY (RADREMI):A PROSPECTIVE PILOT STUDY

Abstract BACKGROUND The combination of immunotherapy and single-fraction stereotactic radiosurgery (SRS) for treatment of metastatic brain disease has yielded symptomatic radiation necrosis rates as high as 16%. The aim of this study was to evaluate the toxicity of dose reduced stereotactic radiosurgery (SRS) in patients receiving concurrent immune checkpoint inhibitors (ICI). METHODS RADREMI is a prospective, single arm, phase 1 pilot study evaluating adults with 1-10 brain metastases on MRI receiving ICI within 30 days of treatment. SRS was delivered using dose reduction: 18 Gy for lesions 0-2 cm, 14 Gy for lesions 2.1-3 cm, and 12 Gy for lesions 3.1-4 cm. Patients were evaluated at 6-months with regard to symptomatic radiation necrosis, defined as a 6-month rate of clinical symptomatology requiring steroid administration, bevacizumab, and/or operative intervention concomitant with advanced and routine brain imaging findings consistent with radiation necrosis. RESULTS Between 2019 and 2023, 18 eligible patents were entered with 12 evaluated. All patients were treated within the 18 Gy cohort. The median follow up was 13.82 months. The median number of brain metastases treated was 1.5 (inner quartiles 1, 3) with up to 7 lesions treated. The proportion of patients who experienced symptomatic radiation necrosis by 6 months was calculated with the 95% confidence interval tested against a historical proportion of 16%. The incidence of symptomatic radiation necrosis at 6 months was 1 of 12 (0.083; 95% CI: 0.002, 0.385; p-value 0.234) following SRS. CONCLUSIONS Our findings of dose reduced SRS with concurrent ICI unfortunately did not have statistical significance regarding symptomatic radiation necrosis. This was likely due to the small number of evaluable patients. The secondary endpoint of local control is currently under review. Dose reduced SRS with concurrent ICI warrants further studies to evaluate toxicity and local control.

Renal Artery Stenosis and Mid-Aortic Syndrome in Children—A Review

Background: Renal artery stenosis (RAS) and mid-aortic syndrome (MAS) are significant yet under-recognized causes of pediatric hypertension. RAS is characterized by the narrowing of the renal arteries, while MAS involves the stenosis of the abdominal aorta along with its associated vessels. The etiologies of RAS and MAS often involve genetic factors and acquired conditions such as fibromuscular dysplasia and Takayasu arteritis, contributing to their complex clinical presentations. Despite advancements in diagnostic imaging, challenges remain in effectively identifying these conditions. Pharmacological treatment can achieve partial blood pressure control, but it usually does not lead to complete recovery. Treatment options range from angioplasty to more definitive surgical interventions such as renal artery reimplantation and aorto-aortic bypass, tailored according to the specific pathology and extent of the disease. Methods: This review explores the diagnosis and management of RAS and MAS in children, highlighting the necessity for early detection and showcasing the evolving landscape of treatment. Conclusions: We advocate for a multidisciplinary approach that includes advanced imaging for effective diagnosis and tailored therapy. By integrating the latest research and clinical practices, this article provides valuable insights into managing complex vascular conditions in the pediatric population, ultimately aiming to enhance the quality of life for affected individuals.

Unveiling the power of artificial intelligence for image-based diagnosis and treatment in endodontics: An ally or adversary?

Artificial intelligence (AI), a field within computer science, uses algorithms to replicate human intelligence tasks such as pattern recognition, decision-making and problem-solving through complex datasets. In endodontics, AI is transforming diagnosis and treatment by applying deep learning algorithms, notably convolutional neural networks, which mimic human brain function to analyse two-dimensional (2D) and three-dimensional (3D) data. This article provides an overview of AI applications in endodontics, evaluating its use in 2D and 3D imaging and examining its role as a beneficial tool or potential challenge. Through a narrative review, the article explores AI's use in 2D and 3D imaging modalities, discusses their limitations and examines future directions in the field. AI significantly enhances endodontic practice by improving diagnostic accuracy, workflow efficiency, and treatment planning. In 2D imaging, AI excels at detecting periapical lesions on both periapical and panoramic radiographs, surpassing expert radiologists in accuracy, sensitivity and specificity. AI also accurately detects and classifies radiolucent lesions, such as radicular cysts and periapical granulomas, matching the precision of histopathology analysis. In 3D imaging, AI automates the segmentation of fine structures such as pulp chambers and root canals on cone-beam computed tomography scans, thereby supporting personalized treatment planning. However, a significant limitation highlighted in some studies is the reliance on in vitro or ex vivo datasets for training AI models. These datasets do not replicate the complexities of clinical environments, potentially compromising the reliability of AI applications in endodontics. Despite advancements, challenges remain in dataset variability, algorithm generalization, and ethical considerations such as data security and privacy. Addressing these is essential for integrating AI effectively into clinical practice and unlocking its transformative potential in endodontic care. Integrating radiomics with AI shows promise for enhancing diagnostic accuracy and predictive analytics, potentially enabling automated decision support systems to enhance treatment outcomes and patient care. Although AI enhances endodontic capabilities through advanced imaging analyses, addressing current limitations and fostering collaboration between AI developers and dental professionals are essential. These efforts will unlock AI's potential to achieve more predictable and personalized treatment outcomes in endodontics, ultimately benefiting both clinicians and patients alike.

DISP-03. HEALTH DISPARITIES IN NEURO-ONCOLOGY

Abstract Significant disparities in diagnosis, research, and treatment exist in neuro-oncology. Patients who identify as racial or ethnic minorities, sexual or gender minorities, elderly, rural, or have low socioeconomic status are more likely to have adverse outcomes. Using PubMed and expert opinion, we summarized the existing literature on health disparities in neuro-oncology. We categorized disparities based on primary central nervous system tumors (CNS), secondary CNS tumors, pediatric neuro-oncology, clinical trial enrollment and diversity, and financial toxicity. For patients with primary CNS tumors, we found that marginalized groups faced delays in diagnosis, lower rates of resection, and lower rates of postoperative radiation. For secondary CNS tumors, marginalized groups had lower rates of indicated cancer screening, less access to genetic testing, less access to advanced imaging, and lower rates of stereotactic radiosurgery and targeted therapies. Pediatric neuro-oncology patients had differences in morbidity and mortality based on socioeconomic status and race and faced substantial delays in diagnosis. Financial toxicity, the side effects of the high financial cost of a cancer diagnosis, disproportionately affects marginalized populations. This may be further exacerbated by the use of long-term medications such as IDH inhibitors. There is also unequal representation of diverse populations in neuro-oncology clinical trials. Compared to other cancer subspecialties, there is less available data on disparities, however, the types of disparities such as delays in diagnosis and outcomes are similar. Notably, there are not many interventions focused on mitigating these disparities. There needs to be additional research on health disparities in neuro-oncology, including both descriptions of existing disparities, but also on methods and interventions to address these disparities.

Comprehensive Management of Cholesteatoma in Otitis Media: Diagnostic Challenges, Imaging Advances, and Surgical Outcome

Background: This study presents a comprehensive analysis of cholesteatoma of the middle ear, focusing on its clinical presentation, diagnostic imaging, and treatment outcomes. Cholesteatomas are defined by the keratinized squamous epithelium within the middle ear, leading to significant bone erosion, often affecting the ossicular chain and surrounding structures. Methods: The study explores various mechanisms involved in cholesteatoma progression, including enzymatic lysis, inflammatory responses, and neurotrophic disturbances. The study conducted a retrospective clinical and statistical review of 580 patients over a 20-year period (2003–2023), highlighting the role of advanced imaging, including computed tomography (CT) and diffusion-weighted magnetic resonance imaging (DWI), in preoperative planning and postoperative follow-up. Results: Findings revealed that early detection and intervention are crucial in preventing severe complications such as intracranial infection and hearing loss. Surgical treatment primarily involved tympanoplasty and mastoidectomy, with a recurrence rate of 1.55% within two years. The study underscores the importance of integrating imaging advancements into clinical decision-making to enhance patient outcomes and suggests further investigation into molecular mechanisms underlying cholesteatoma progression and recurrence. Histopathological and microbiological analysis was performed to identify pathological patterns and microbial agents. Conclusions: The study highlights the importance of early diagnosis and intervention to prevent complications such as intracranial infections and permanent hearing loss, while also emphasizing the role of advanced imaging techniques in the management and long-term monitoring of cholesteatoma patients.

Comparative analysis of vision transformers and fine-tuned transfer learning models for brain tumor classification

Brain tumors are a primary factor causing cancer-related deaths globally, and their classification remains a significant research challenge due to the variability in tumor intensity, size, and shape, as well as the similar appearances of different tumor types. Accurate differentiation is further complicated by these factors, making diagnosis difficult even with advanced imaging techniques such as magnetic resonance imaging (MRI). Recent techniques in artificial intelligence (AI), in particular deep learning (DL), have improved the speed and accuracy of medical image analysis, but they still face challenges like overfitting and the need for large annotated datasets. This study addresses these challenges by presenting two approaches for brain tumor classification using MRI images. The first approach involves fine-tuning transfer learning cutting-edge models, including SEResNet, ConvNeXtBase, and ResNet101V2, with global average pooling 2D and dropout layers to minimize overfitting and reduce the need for extensive preprocessing. The second approach leverages the Vision Transformer (ViT), optimized with the AdamW optimizer and extensive data augmentation. Experiments on the BT-Large-4C dataset demonstrate that SEResNet achieves the highest accuracy of 97.96%, surpassing ViT’s 95.4%. These results suggest that fine-tuning and transfer learning models are more effective at addressing the challenges of overfitting and dataset limitations, ultimately outperforming the Vision Transformer and existing state-of-the-art techniques in brain tumor classification.