Predictors of futile recanalization in nonagenarians treated with mechanical thrombectomy: a multi-center observational study.

BACKGROUND: There is a lack of data regarding patients aged 90 years or older undergoing mechanical thrombectomy and their predictors of futile recanalization. AIMS: We sought to evaluate the predictors of futile recanalization in patients ≥ 90 years with large vessel occlusion undergoing mechanical thrombectomy. METHODS: This multi-center observational retrospective study included patients ≥ 90 years consecutively treated with mechanical thrombectomy in four thrombectomy capable centers between January 1st, 2016 and 30th March 2023. Futile recanalization was defined as large vessel occlusion patients experiencing a 90-day poor outcome (mRS 3-6) despite successful recanalization (mTICI ≥ 2b) after mechanical thrombectomy. RESULTS: Our cohort included 139 patients ≥ 90 years with acute ischemic stroke due to anterior circulation large vessel occlusion treated with mechanical thrombectomy. One hundred seventeen of one hundred thirty-nine patients ≥ 90 years who achieved successful recanalization were included in the analysis (seventy-six female (64.9%)), of whom thirty-one (26.49%) experienced effective recanalization and eighty-six (73.51%) experienced futile recanalization. Patients with futile recanalization had higher NIHSS on admission (p < 0.001); they were less frequently treated with intravenous thrombolysis (p = 0.048), had more often general anesthesia (p = 0.011), and longer door to groin puncture delay (p = 0.002). Univariable regression analysis showed that use of intravenous thrombolysis (0.29, 95% CI 0.02-0.79, p = 0.034) and site of occlusion distal vs proximal (0.34, 95% CI 0.11-0.97, p = 0.044) were associated with reduced probability of futile recanalization while NIHSS on admission (1.29, 95% CI 1.16-1.45, p < 0.001), NIHSS at 24 h (1.15, 95% CI 1.07-1.25, p = 0.002), type of anesthesia used (4.18, 95% CI 1.57-11.08, p = 0.004), and door to groin puncture time (1.02, 95% CI 1.00-1.05, p = 0.005) were associated with increased probability of futile recanalization. Multivariable regression analysis showed that use of intravenous thrombolysis (0.44, 95% CI 0.09-0.88, p = 0.039) was associated with reduced probability of futile recanalization. CONCLUSION: Our study seems to suggest that mechanical thrombectomy with intravenous thrombolysis is associated with reduced probability of futile recanalization in a multi-center cohort of patients aged 90 years or older.

Generative pretrained transformer-4, an artificial intelligence text predictive model, has a high capability for passing novel written radiology exam questions.

PURPOSE: AI-image interpretation, through convolutional neural networks, shows increasing capability within radiology. These models have achieved impressive performance in specific tasks within controlled settings, but possess inherent limitations, such as the inability to consider clinical context. We assess the ability of large language models (LLMs) within the context of radiology specialty exams to determine whether they can evaluate relevant clinical information. METHODS: A database of questions was created with official sample, author written, and textbook questions based on the Royal College of Radiology (United Kingdom) FRCR 2A and American Board of Radiology (ABR) Certifying examinations. The questions were input into the Generative Pretrained Transformer (GPT) versions 3 and 4, with prompting to answer the questions. RESULTS: One thousand seventy-two questions were evaluated by GPT-3 and GPT-4. 495 (46.2%) were for the FRCR 2A and 577 (53.8%) were for the ABR exam. There were 890 single best answers (SBA), and 182 true/false questions. GPT-4 was correct in 629/890 (70.7%) SBA and 151/182 (83.0%) true/false questions. There was no degradation on author written questions. GPT-4 performed significantly better than GPT-3 which selected the correct answer in 282/890 (31.7%) SBA and 111/182 (61.0%) true/false questions. Performance of GPT-4 was similar across both examinations for all categories of question. CONCLUSION: The newest generation of LLMs, GPT-4, demonstrates high capability in answering radiology exam questions. It shows marked improvement from GPT-3, suggesting further improvements in accuracy are possible. Further research is needed to explore the clinical applicability of these AI models in real-world settings.

Early Outcomes of the Pipeline Vantage Flow Diverter : A Multicentre Study.

PURPOSE: The recently introduced Pipeline Vantage Embolization Device with Shield Technology is the fourth generation of Pipeline flow diverter devices. Due to the relatively high rate of intraprocedural technical complications, modifications were subsequently made to the device after a limited release of the device in 2020. This study aimed to evaluate the safety and efficacy of the modified version of this device. METHODS: This was a multicentre retrospective series. The primary efficacy endpoint was aneurysm occlusion in the absence of retreatment. The primary safety endpoint was any neurological morbidity or death. Ruptured and unruptured aneurysms were included in the study. RESULTS: A total of 52 procedures were performed for 60 target aneurysms. Treatment was performed on 5 patients with ruptured aneurysms. The technical success rate was 98%. The mean clinical follow-up time was 5.5 months. In patients presenting with unruptured aneurysms there were no deaths, 3 (6.4%) major complications and 7 (13%) minor complications. In the five patients presenting with subarachnoid haemorrhage there were 2 (40%) major complications with 1 (20%) of these resulting in death, and 1 (20%) minor complication. Of the patients 29 (56%) had undergone 6­monthly postprocedural angiographic imaging with a mean time of 6.6 months demonstrating that 83% of patients had achieved adequate occlusion (RROC1/2) of the aneurysm. CONCLUSIONS: In this non-industry-sponsored study, the occlusion rates and safety outcomes were similar to those seen in previously published studies with flow diverter devices and earlier generation Pipeline devices. Modifications to the device appear to have improved ease of deployment.

Multiparametric ultrasound imaging characteristics of multiple testicular adrenal rest tumours in congenital adrenal hyperplasia.

INTRODUCTION: Testicular adrenal rest cell tumours (TART) are rare benign adrenocorticotropic hormone-dependent testicular tumours, which can develop in patients with congenital adrenal hyperplasia. If left untreated, they can cause testicular tissue damage and infertility. Ultrasound is the imaging modality of choice allowing for non-invasive diagnosis provided that characteristic features are seen. In recent times, magnetic resonance imaging characteristics have also been described to aid diagnosis. CASE REPORT: This case describes the imaging features of multiple bilateral TART in a young patient with congenital adrenal hyperplasia. Traditional greyscale and colour Doppler ultrasound demonstrated intratesticular, predominantly hypoechoic areas, with increased surrounding colour Doppler flow. In addition, contrast-enhanced ultrasound and strain elastography were performed, showing increased TART vascularisation and increased stiffness in the hypoechoic areas. Subsequent magnetic resonance imaging confirmed bilateral lobulated, well demarcated, intratesticular lesions, which appeared predominantly isointense on T1-weighted imaging, hypointense on T2-weighted imaging, with heterogeneous enhancement following gadolinium administration. DISCUSSION: This case illustrates the sonographic features including greyscale, colour Doppler, contrast and elastography ultrasound of TART in a patient with congenital adrenal hyperplasia. Both contrast-enhanced ultrasound and elastography can provide information about tissue properties not normally derived from conventional ultrasound and aid accurate diagnosis. Additional magnetic resonance imaging is not normally required with typical ultrasound appearances. The unusual findings seen on the ultrasound examination were likely secondary to poor compliance with treatment. CONCLUSION: Familiarity and recognition of characteristic and uncommon imaging features of these tumours are important to avoid misdiagnosis and surgical intervention.

Imaging Biomarkers of Glioblastoma Treatment Response: A Systematic Review and Meta-Analysis of Recent Machine Learning Studies.

OBJECTIVE: Monitoring biomarkers using machine learning (ML) may determine glioblastoma treatment response. We systematically reviewed quality and performance accuracy of recently published studies. METHODS: Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis: Diagnostic Test Accuracy, we extracted articles from MEDLINE, EMBASE and Cochrane Register between 09/2018-01/2021. Included study participants were adults with glioblastoma having undergone standard treatment (maximal resection, radiotherapy with concomitant and adjuvant temozolomide), and follow-up imaging to determine treatment response status (specifically, distinguishing progression/recurrence from progression/recurrence mimics, the target condition). Using Quality Assessment of Diagnostic Accuracy Studies Two/Checklist for Artificial Intelligence in Medical Imaging, we assessed bias risk and applicability concerns. We determined test set performance accuracy (sensitivity, specificity, precision, F1-score, balanced accuracy). We used a bivariate random-effect model to determine pooled sensitivity, specificity, area-under the receiver operator characteristic curve (ROC-AUC). Pooled measures of balanced accuracy, positive/negative likelihood ratios (PLR/NLR) and diagnostic odds ratio (DOR) were calculated. PROSPERO registered (CRD42021261965). RESULTS: Eighteen studies were included (1335/384 patients for training/testing respectively). Small patient numbers, high bias risk, applicability concerns (particularly confounding in reference standard and patient selection) and low level of evidence, allow limited conclusions from studies. Ten studies (10/18, 56%) included in meta-analysis gave 0.769 (0.649-0.858) sensitivity [pooled (95% CI)]; 0.648 (0.749-0.532) specificity; 0.706 (0.623-0.779) balanced accuracy; 2.220 (1.560-3.140) PLR; 0.366 (0.213-0.572) NLR; 6.670 (2.800-13.500) DOR; 0.765 ROC-AUC. CONCLUSION: ML models using MRI features to distinguish between progression and mimics appear to demonstrate good diagnostic performance. However, study quality and design require improvement.

Validating Automated Segmentation Tools in the Assessment of Caudate Atrophy in Huntington's Disease.

Background: Neuroimaging shows considerable promise in generating sensitive and objective outcome measures for therapeutic trials across a range of neurodegenerative conditions. For volumetric measures the current gold standard is manual delineation, which is unfeasible for samples sizes required for large clinical trials. Methods: Using a cohort of early Huntington's disease (HD) patients (n = 46) and controls (n = 35), we compared the performance of four automated segmentation tools (FIRST, FreeSurfer, STEPS, MALP-EM) with manual delineation for generating cross-sectional caudate volume, a region known to be vulnerable in HD. We then examined the effect of each of these baseline regions on the ability to detect change over 15 months using the established longitudinal Caudate Boundary Shift Integral (cBSI) method, an automated longitudinal pipeline requiring a baseline caudate region as an input. Results: All tools, except Freesurfer, generated significantly smaller caudate volumes than the manually derived regions. Jaccard indices showed poorer levels of overlap between each automated segmentation and manual delineation in the HD patients compared with controls. Nevertheless, each method was able to demonstrate significant group differences in volume (p < 0.001). STEPS performed best qualitatively as well as quantitively in the baseline analysis. Caudate atrophy measures generated by the cBSI using automated baseline regions were largely consistent with those derived from a manually segmented baseline, with STEPS providing the most robust cBSI values across both control and HD groups. Conclusions: Atrophy measures from the cBSI were relatively robust to differences in baseline segmentation technique, suggesting that fully automated pipelines could be used to generate outcome measures for clinical trials.

Accuracy and complication rates of external ventricular drain placement with twist drill and bolt system versus standard trephine and tunnelation: a retrospective population-based study.

BACKGROUND: An external ventricular drain (EVD) is typically indicated in the presence of hydrocephalus and increased intracranial pressure (ICP). Procedural challenges have prompted the development of different methods to improve accuracy, safety, and logistics. OBJECTIVES: EVD placement and complications rates were compared using two surgical techniques; the standard method (using a 14-mm trephine burrhole with the EVD tunnelated through the skin) was compared to a less invasive method (EVD placed through a 2.7-3.3-mm twist drill burrhole and fixed to the bone with a bolt system). METHODS: Retrospective observational study in a single-centre setting between 2008 and 2018. EVD placement was assessed using the Kakarla scoring system. We registered postoperative complications, surgery duration and number of attempts to place the EVD. RESULTS: Two hundred seventy-two patients received an EVD (61 bolt EVDs, 211 standard EVDs) in the study period. Significant differences between the bolt system and the standard method were observed in terms of revision surgeries (8.2% vs. 21.5%, p = 0.020), surgery duration (mean 16.5 vs. 28.8 min, 95% CI 7.64, 16.8, p < 0.001) and number of attempts to successfully place the first EVD (mean 1.72 ± 1.2 vs. 1.32 ± 0.8, p = 0.017). There were no differences in accuracy of placement or complication rates. CONCLUSIONS: The two methods show similar accuracy and postoperative complication rates. Observed differences in both need for revisions and surgery duration favoured the bolt group. Slightly, more attempts were needed to place the initial EVD in the bolt group, perhaps reflecting lower flexibility for angle correction with a twist drill approach.

PET imaging in glioma: techniques and current evidence.

PET holds potential to provide additional information about tumour metabolic processes, which could aid brain tumour differential diagnosis, grading, molecular subtyping and/or the distinction of therapy effects from disease recurrence. This review discusses PET techniques currently in use for untreated and treated glioma characterization and aims to critically assess the evidence for different tracers ([F]Fluorodeoxyglucose, choline and amino acid tracers) in this context.