Single-View Fluoroscopic X-Ray Pose Estimation: A Comparison of Alternative Loss Functions and Volumetric Scene Representations.

Many tasks performed in image-guided procedures can be cast as pose estimation problems, where specific projections are chosen to reach a target in 3D space. In this study, we construct a framework for fluoroscopic pose estimation and compare alternative loss functions and volumetric scene representations. We first develop a differentiable projection (DiffProj) algorithm for the efficient computation of Digitally Reconstructed Radiographs (DRRs) from either Cone-Beam Computerized Tomography (CBCT) or neural scene representations.

Precise Image-level Localization of Intracranial Hemorrhage on Head CT Scans with Deep Learning Models Trained on Study-level Labels.

Purpose To develop a highly generalizable weakly supervised model to automatically detect and localize image-level intracranial hemorrhage (ICH) by using study-level labels. Materials and Methods In this retrospective study, the proposed model was pretrained on the image-level Radiological Society of North America dataset and fine-tuned on a local dataset by using attention-based bidirectional long short-term memory networks. This local training dataset included 10 699 noncontrast head CT scans in 7469 patients, with ICH study-level labels extracted from radiology reports.

Temporal Changes on Postgadolinium MR Vessel Wall Imaging Captures Enhancement Kinetics of Intracranial Atherosclerotic Plaques and Aneurysms.

Background And Purpose: Analysis of vessel wall contrast kinetics (ie, wash-in/washout) is a promising method for the diagnosis and risk-stratification of intracranial atherosclerotic disease plaque (ICAD-P) and the intracranial aneurysm walls (IA-W). We used black-blood MR imaging or MR vessel wall imaging to evaluate the temporal relationship of gadolinium contrast uptake kinetics in ICAD-Ps and IA-Ws compared with normal anatomic reference structures.

Materials And Methods: Patients with ICAD-Ps or IAs who underwent MR vessel wall imaging with precontrast, early postcontrast (5-15 minutes), and delayed postcontrast (20-30 minutes) 3D T1-weighted TSE sequences were retrospectively studied.

Bivalirudin as a substitute for heparin in neurointervention for patients with heparin-induced thrombocytopenia.

Objectives: Heparin-induced thrombocytopenia is a known complication of heparin exposure with potentially life-threatening sequelae. Direct thrombin inhibitors can be substituted for heparin in patients with heparin-induced thrombocytopenia that require anticoagulation. However, the use of direct thrombin inhibitors as a substitute for heparin has not been widely reported in the neuroendovascular literature.

MR Vessel Wall Imaging for Atherosclerosis and Vasculitis.

Conventional imaging modalities, such as computed tomography angiography, MR angiography, transcranial Doppler ultrasonography, and digital subtraction angiography, are utilized in evaluating intraluminal or intravascular pathology of the intracranial vessels. Limitations of luminal imaging techniques can lead to inaccurate diagnosis, evaluation, and risk stratification, as many cerebrovascular pathologies contain an extrinsic vessel wall component. Furthermore, vessel wall imaging can provide information regarding extent, treatment response, and biopsy targets for vasculitis cases.

Background Subtraction Angiography with Deep Learning Using Multi-frame Spatiotemporal Angiographic Input.

Catheter Digital Subtraction Angiography (DSA) is markedly degraded by all voluntary, respiratory, or cardiac motion artifact that occurs during the exam acquisition. Prior efforts directed toward improving DSA images with machine learning have focused on extracting vessels from individual, isolated 2D angiographic frames. In this work, we introduce improved 2D + t deep learning models that leverage the rich temporal information in angiographic timeseries.

Clot composition and recanalization outcomes in mechanical thrombectomy.

Background: Mechanical thrombectomy (MT) has become standard for large vessel occlusions, but rates of complete recanalization are suboptimal. Previous reports correlated radiographic signs with clot composition and a better response to specific techniques. Therefore, understanding clot composition may allow improved outcomes.

Holohemispheric Prostate Carcinoma Dural Metastasis Mimicking Subdural Hematoma: Case Report and Review of the Literature.

Prostate carcinomas are the most common malignancy to metastasize to the dura. These metastases can commonly mimic subdural hematomas and may similarly present with brain compression. The optimal management and outcomes after surgical management are not well characterized.

Histological composition of retrieved emboli in acute ischemic stroke is independent of pre-thrombectomy alteplase use.

Background And Purpose: Given recent evidence suggesting the clot composition may be associated with revascularization outcomes and stroke etiology, clot composition research has been a topic of growing interest. It is currently unclear what effect, if any, pre-thrombectomy thrombolysis has on clot composition. Understanding this association is important as it is a potential confounding variable in clot composition research.

Unplanned readmission after carotid stenting versus endarterectomy: analysis of the United States Nationwide Readmissions Database.

Background: Hospital readmissions are costly and reflect negatively on care delivered.

Objective: To have a better understanding of unplanned readmissions after carotid revascularization, which might help to prevent them.

Methods: The Nationwide Readmissions Database was used to determine rates and reasons for unplanned readmission following carotid endarterectomy (CEA) and carotid artery stenting (CAS).

Quantification of clot spatial heterogeneity and its impact on thrombectomy.

Background: Compositional and structural features of retrieved clots by thrombectomy can provide insight into improving the endovascular treatment of ischemic stroke. Currently, histological analysis is limited to quantification of compositions and qualitative description of the clot structure. We hypothesized that heterogeneous clots would be prone to poorer recanalization rates and performed a quantitative analysis to test this hypothesis.

Case Report: Anterior Spinal Cord Ischemia Following Embolization of Cerebellar Arteriovenous Malformation: An Illustrative Case and Review of Spinal Cord Vascular Anatomy.

Spinal cord ischemia (SCI) is a rare entity with high mortality and morbidity which can arise from causes such as atherosclerosis, aortic dissection or aneurysm, thromboembolic events or systemic hypotension, and is a potential complication of spinal surgery. Published literature contains very few reports of SCI as a complication of intracranial interventions, highlighting the uncommon nature of SCI in these circumstances. We report the occurrence of anterior SCI in a 69-year-old patient following successful embolization of a cerebellar arteriovenous malformation (AVM), marked by upper extremity weakness, lower extremity paraplegia, loss of bladder and bowel control, and hypercapnic respiratory failure requiring mechanical ventilation.

Histological evaluation of acute ischemic stroke thrombi may indicate the occurrence of vessel wall injury during mechanical thrombectomy.

Background: Several animal studies have demonstrated that mechanical thrombectomy (MT) for acute ischemic stroke (AIS) may cause vessel wall injury (VWI). However, the histological changes in human cerebral arteries following MT are difficult to determine.

Objective: To investigate the occurrence of VWI during MT by histological and immunohistochemical evaluation of AIS clots.

Pipeline embolization of cerebral aneurysms in pediatric patients: combined systematic review of patient-level data and multicenter retrospective review.

Objective: Cerebral aneurysms in the pediatric population are rare and optimal treatment strategies are not as well characterized as in adults. The Pipeline embolization device (PED) is an endoluminal flow diverter that is commonly used to treat aneurysms in adults, but experience with this device in children is limited. The authors sought to further characterize PED use and outcomes in this specific population by performing both a systematic review of patient-level data from studies reporting the use of the PED to treat pediatric aneurysms and a retrospective review of their experience.

Per pass analysis of thrombus composition retrieved by mechanical thrombectomy.

Background And Aim: Mechanical thrombectomy (MT) for large vessel occlusion often requires multiple passes to retrieve the entire thrombus load. In this multi-institutional study we sought to examine the composition of thrombus fragments retrieved with each pass during MT.

Methods: Patients who required multiple passes during thrombectomy were included.

Direct percutaneous transcarotid approach for embolization of dural sinus malformation in a premature neonate: A case report.

Direct percutaneous TCAA can be a feasible access for intracranial interventions in neonates with LBW and unavailable UA access.

Association between clot composition and stroke origin in mechanical thrombectomy patients: analysis of the Stroke Thromboembolism Registry of Imaging and Pathology.

Background: We retrospectively evaluated the composition of retrieved clots from ischemic stroke patients to study the association between histological composition and stroke etiology METHODS: Consecutive patients enrolled in the Stroke Thromboembolism Registry of Imaging and Pathology (STRIP) were included in this study. All patients underwent mechanical thrombectomy and retrieved clots were sent to a central core lab for processing. Histological analysis was performed using martius scarlet blue (MSB) staining, and quantification for red blood cells (RBCs), white blood cells (WBCs), fibrin and platelets was performed using Orbit Image Software.

DeepCOVID-XR: An Artificial Intelligence Algorithm to Detect COVID-19 on Chest Radiographs Trained and Tested on a Large U.S. Clinical Data Set.

Background There are characteristic findings of coronavirus disease 2019 (COVID-19) on chest images. An artificial intelligence (AI) algorithm to detect COVID-19 on chest radiographs might be useful for triage or infection control within a hospital setting, but prior reports have been limited by small data sets, poor data quality, or both. Purpose To present DeepCOVID-XR, a deep learning AI algorithm to detect COVID-19 on chest radiographs, that was trained and tested on a large clinical data set.

Magnetization Transfer Ratio and Morphometrics of the Spinal Cord Associates with Surgical Recovery in Patients with Degenerative Cervical Myelopathy.

Objectives: We assessed the prognostic value of the preoperative magnetization transfer ratio (MTR) and morphometrics of the spinal cord in patients with degenerative cervical myelopathy (DCM) in a longitudinal cohort study.

Methods: Thirteen subjects with DCM underwent 3T magnetization transfer imaging. The MTR was calculated for the spinal cord regions and specific white matter tracts.

Conservative Management and Natural History of Ruptured Basilar Perforator Artery Aneurysms: Two Cases and Literature Review.

Background: Basilar perforator aneurysms are rare causes of subarachnoid hemorrhage and their natural history is poorly characterized. Although various treatment strategies have been reported, conservative management is an option that has been associated with a high likelihood of spontaneous resolution.

Case Description: Here we present 2 cases of subarachnoid hemorrhage, 1 diffuse and the other perimesencephalic, due to small ruptured basilar perforator artery aneurysms.

Texture analysis of placental MRI: can it aid in the prenatal diagnosis of placenta accreta spectrum?

Purpose: To determine if texture analysis can differentiate placenta accreta spectrum (PAS) from normal placenta on MRI.

Methods: We performed retrospective image analysis of 80 patients, comprised of 46 patients with PAS and 34 patients without PAS. Histopathology was used as the reference standard.

Machine Learning for the Prediction of Cervical Spondylotic Myelopathy: A Post Hoc Pilot Study of 28 Participants.

Background: Cervical spondylotic myelopathy (CSM) severity and presence of symptoms are often difficult to predict based simply on clinical imaging alone. Similarly, improved machine learning techniques provide new tools with immense clinical potential.

Methods: A total of 14 patients with CSM and 14 controls underwent imaging of the cervical spine.

Non-centered spike-triggered covariance analysis reveals neurotrophin-3 as a developmental regulator of receptive field properties of ON-OFF retinal ganglion cells.

The functional separation of ON and OFF pathways, one of the fundamental features of the visual system, starts in the retina. During postnatal development, some retinal ganglion cells (RGCs) whose dendrites arborize in both ON and OFF sublaminae of the inner plexiform layer transform into RGCs with dendrites that monostratify in either the ON or OFF sublamina, acquiring final dendritic morphology in a subtype-dependent manner. Little is known about how the receptive field (RF) properties of ON, OFF, and ON-OFF RGCs mature during this time because of the lack of a reliable and efficient method to classify RGCs into these subtypes.

Extracellular stimulation of mouse retinal ganglion cells with non-rectangular voltage-controlled waveforms.

Neural prostheses rely upon electric stimulation to control neural activity. However, electrode corrosion and tissue damage may result from the injection of high charge densities. During electrical stimulation with traditional voltage-controlled square-wave pulses, the current density distribution on the surface of the stimulating electrode is highly nonuniform, with the highest current densities located at the edge of disk-shaped electrodes.