Advances in robotic technology have been adopted in various subspecialties of both open and minimally invasive surgery, offering benefits such as enhanced surgical precision and accuracy with reduced fatigue of the surgeon. Despite the advantages, robotic applications to endovascular neurosurgery have remained largely unexplored because of technical challenges such as the miniaturization of robotic devices that can reach the complex and tortuous vasculature of the brain. Although some commercial systems enable robotic manipulation of conventional guidewires for coronary and peripheral vascular interventions, they remain unsuited for neurovascular applications because of the considerably smaller and more tortuous anatomy of cerebral arteries. Here, we present a teleoperated robotic neurointerventional platform based on magnetic manipulation. Our system consists of a magnetically controlled guidewire, a robot arm with an actuating magnet to steer the guidewire, a set of motorized linear drives to advance or retract the guidewire and a microcatheter, and a remote-control console to operate the system under real-time fluoroscopy. We demonstrate our system’s capability to navigate narrow and winding pathways both in vitro with realistic neurovascular phantoms representing the human anatomy and in vivo in the porcine brachial artery with accentuated tortuosity for preclinical evaluation. We further demonstrate telerobotically assisted therapeutic procedures including coil embolization and clot retrieval thrombectomy for treating cerebral aneurysms and ischemic stroke, respectively. Our system could enable safer and quicker access to hard-to-reach lesions while minimizing the radiation exposure to physicians and open the possibility of remote procedural services to address challenges in current stroke systems of care.

BACKGROUND AND PURPOSE:Compressed sensing-sensitivity encoding is a promising MR imaging acceleration technique. This study compares the image quality of compressed sensing-sensitivity encoding accelerated imaging with conventional MR imaging sequences. MATERIALS AND METHODS:Patients with known, treated, or suspected brain tumors underwent compressed sensing-sensitivity encoding accelerated 3D T1-echo-spoiled gradient echo or 3D T2-FLAIR sequences in addition to the corresponding conventional acquisition as part of their clinical brain MR imaging. Two neuroradiologists blinded to sequence and patient information independently evaluated both the accelerated and corresponding conventional acquisitions. The sequences were evaluated on 4-or 5-point Likert scales for overall image quality, SNR, extent/severity of artifacts, and gray-white junction and lesion boundary sharpness. SNR and contrast-to-noise ratio values were compared. RESULTS:Sixty-six patients were included in the study. For T1-echo-spoiled gradient echo, image quality in all 5 metrics was slightly better for compressed sensing-sensitivity encoding than conventional images on average, though it was not statistically significant, and the lower bounds of the 95% confidence intervals indicated that compressed sensing-sensitivity encoding image quality was within 10% of conventional imaging. For T2-FLAIR, image quality of the compressed sensing-sensitivity encoding images was within 10% of the conventional images on average for 3 of 5 metrics. The compressed sensing-sensitivity encoding images had somewhat more artifacts (P ϭ .068) and less gray-white matter sharpness (P ϭ .36) than the conventional images, though neither difference was significant. There was no significant difference in the SNR and contrast-to-noise ratio. There was 25% and 35% scan-time reduction with compressed sensing-sensitivity encoding for FLAIR and echo-spoiled gradient echo sequences, respectively. CONCLUSIONS:Compressed sensing-sensitivity encoding accelerated 3D T1-echo-spoiled gradient echo and T2-FLAIR sequences of the brain show image quality similar to that of standard acquisitions with reduced scan time. Compressed sensing-sensitivity encoding may reduce scan time without sacrificing image quality. ABBREVIATIONS:CNR ϭ contrast-to-noise ratio; CS ϭ compressed sensing; SENSE ϭ sensitivity encoding; SPGR ϭ echo-spoiled gradient echo

In this pilot study, we determined that intraplaque enhancement could be reliably evaluated with the use of cross-sectional imaging and analysis of vessels/plaques by use of conventional neuroanatomic MR imaging protocols. In addition, we observed a strong association between intraplaque enhancement in severe intracranial atherosclerotic disease lesions and ischemic events with the use of conventional MR imaging. Our preliminary study suggests that T1 gadolinium-enhancing plaques may be an indicator of progressing or symptomatic intracranial atherosclerotic disease.

Blunt cerebrovascular injury (BCVI) is a relatively rare but potentially devastating finding in patients with high-energy blunt force trauma or direct cervical and/or craniofacial injury. The radiologist plays an essential role in identifying and grading the various types of vascular injury, including minimal intimal injury, dissection with raised intimal flap or intraluminal thrombus, intramural hematoma, pseudoaneurysm, occlusion, transection, and arteriovenous fistula. Early identification of BCVI is important, as treatment with antithrombotic therapy has been shown to reduce the incidence of postinjury ischemic stroke. Patients with specific mechanisms of injury, particular imaging findings, or certain clinical signs and symptoms have been identified as appropriate and cost-effective for BCVI screening. Although digital subtraction angiography was previously considered the standard examination for screening, technologic improvements have led to its replacement with computed tomographic angiography. Of note, although not appropriate for screening, improvements in magnetic resonance angiography with vessel wall imaging hold promise as supplemental imaging studies that may improve diagnostic specificity for vessel wall injuries. Understanding the screening criteria, imaging modalities of choice, imaging appearances, and grading of BCVI is essential for the radiologist to ensure fast and appropriate diagnosis and treatment. This article details the imaging evaluation of BCVI and discusses the clinical and follow-up imaging implications of specific injury findings. RSNA, 2018.

BACKGROUND AND PURPOSE:Pathological changes in the intracranial aneurysm wall may lead to increases in its permeability; however the clinical significance of such changes has not been explored. The purpose of this pilot study was to quantify intracranial aneurysm wall permeability (K

Integrins play a key role in cell–cell and cell–matrix interactions. Artificial surfaces grafted with integrin ligands, mimicking natural interfaces, have been used to study integrin-mediated cell adhesion. Here we report the use of a new chemical engineering technology in combination with single-molecule nanomechanical measurements to quantify peptide binding to integrins. We prepared latex beads with covalently-attached dextran. The beads were then functionalized with the bioactive peptides, cyclic RGDFK (cRGD) and the fibrinogen γC-dodecapeptide (H12), corresponding to the active sites for fibrinogen binding to the platelet integrin αIIbβ3. Using optical tweezers-based force spectroscopy to measure non-specific protein–protein interactions, we found the dextran-coated beads nonreactive towards fibrinogen, thus providing an inert platform for biospecific modifications. Using periodate oxidation followed by reductive amination, we functionalized the bead-attached dextran with either cRGD or H12 and used the peptide-grafted beads to measure single-molecule interactions with the purified αIIbβ3. Bimolecular force spectroscopy revealed that the peptide-functionalized beads were highly and specifically reactive with the immobilized αIIbβ3. Further, the cRGD- and H12-functionalized beads displayed a remarkable interaction profile with a bimodal force distribution up to 90 pN. The cRGD–αIIbβ3 interactions had greater binding strength than that of H12–αIIbβ3, indicating that they are more stable and resistant mechanically, consistent with the platelet reactivity of RGD-containing ligands. Thus, the results reported here describe the mechanistic characteristics of αIIbβ3–ligand interactions, confirming the utility of peptide-functionalized latex beads for the quantitative analysis of molecular recognition.

BackgroundTo analyse the clinical characteristics of COVID-19 with acute ischaemic stroke (AIS) and identify factors predicting functional outcome.MethodsMulticentre retrospective cohort study of COVID-19 patients with AIS who presented to 30 stroke centres in the USA and Canada between 14 March and 30 August 2020. The primary endpoint was poor functional outcome, defined as a modified Rankin Scale (mRS) of 5 or 6 at discharge. Secondary endpoints include favourable outcome (mRS ≤2) and mortality at discharge, ordinal mRS (shift analysis), symptomatic intracranial haemorrhage (sICH) and occurrence of in-hospital complications.ResultsA total of 230 COVID-19 patients with AIS were included. 67.0% (154/230) were older than 60 years, while 33.0% (76/230) were younger. Median (IQR) National Institutes of Health Stroke Scale (NIHSS) at presentation was 12.0 (17.0) and 42.8% (89/208) presented with large vessel occlusion (LVO). Approximately 50.2% (102/203) of the patients had poor outcomes with an observed mortality rate of 38.8% (35/219). Age >60 years (aOR: 4.60, 95% CI 1.89 to 12.15, p=0.001), diabetes mellitus (aOR: 2.53, 95% CI 1.14 to 5.79, p=0.025), increased NIHSS at admission (aOR: 1.10, 95% CI 1.05 to 1.16, p<0.001), LVO (aOR: 3.02, 95% CI 1.27 to 7.44, p=0.014) and no IV tPA (aOR: 2.76, 95% CI 1.06 to 7.64, p=0.043) were significantly associated with poor functional outcome.ConclusionThere may be a relationship between COVID-19 associated AIS and severe disability or death. We identified several factors that predict worse outcomes, and these outcomes were more frequent compared with global averages. We found that elevated neutrophil-to-lymphocyte ratio, rather than D-dimer, predicted both morbidity and mortality.

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