Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Mechanical circulatory support (MCS) devices are commonly used in heart failure patients. These devices carry risk for presumably embolic and additionally hemorrhagic stroke. Alterations in blood flow play a key role in stroke pathophysiology, and we aimed to learn more about hemodynamic compromise. In this study, we used transcranial Doppler (TCD) ultrasound to define hemodynamics of commonly used nonpulsatile MCS devices, as well as pulsatile devices, with special attention to the total artificial heart (TAH). ⋯ TCD can detect characteristic waveforms in patients supported by various MCS devices. These device-specific TCD patterns are recognizable and reproducible.
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Recent trials have shown benefit of thrombectomy in patients selected by penumbral imaging in the late (>6 hours) window. However, the role penumbral imaging is not clear in the early (0-6 hours) window. We sought to evaluate if time to treatment modifies the effect of endovascular reperfusion in stroke patients with evidence of salvageable tissue on CT perfusion (CTP). ⋯ Penumbral imaging-based selection of patients for thrombectomy is effective regardless of onset time and yields similar functional outcomes in early and late window patients.
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Comparative Study
Giant Cerebral Aneurysms: Comparing CTA, MRA, and Digital Subtraction Angiography Assessments.
Comprehensive imaging characterization of the morphology and luminal patency of cerebral aneurysms are cornerstones of their successful treatment and subsequent appropriate management. Giant cerebral aneurysms (GCAs), a distinct subgroup of aneurysms, are defined by large size (≥ 25 mm in greatest diameter), complex blood flow dynamics, and a high risk of rupture. The purpose of this study is to explore compare multiple imaging modalities in the assessment of GCAs. ⋯ CTA, 3D TOFMRA, and CEMRA are equivalent in the delineation of size of GCAs. Nevertheless, 3D TOFMRA and CEMRA seem to be inferior to CTA in demonstrating luminal size/patency, likely because of the signal loss resulting from the presence of intraluminal thrombus and flow turbulence. Moreover, CTA is superior to DSA in determining lumen patency in GCAs, probably due to CTA's multipass-related luminal enhancement while DSA general fills the lesion via the first pass of enhancement or soon thereafter. In addition, CTA may also better demonstrate intraluminal thrombus, adjacent anatomical structures, and calcified rims.
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Imaging-based selection of stroke patients for endovascular thrombectomy (EVT) remains an ongoing challenge. Our aim was to determine the value of a combined parameter of ischemic core volume (ICV) and the relative degree of cerebral blood flow in the penumbra for morphologic and clinical outcome prediction. ⋯ In EVT-treated stroke patients, pw-ICV outperforms the more commonly used ICV in the prediction of morphological and functional outcome.
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Three-dimensional cinematic rendering (3DCR) is an emerging postprocessing technique for computed tomography (CT) and CT angiography (CTA) that produces photorealistic, volumetric images. In contrast to conventional volume rendering techniques, 3DCR depicts life-like shadowing and surface reflection, which can improve the perception of depth and complex anatomic spatial relationships. This tool allows clinical neuroimagers to study, explore, and teach the complex relational anatomy of the cerebral vessels and skull in a more intuitive manner. ⋯ Next, we discuss surface rendering as a means of recapitulating the neurologic physical exam. Last, we provide a step-by-step method of simulating the operating room perspective in visualizing cerebrovascular disease. In our experience, 3DCR proves most useful for visualizing structures at the vessel-skull interface, which can be difficult to assess with conventional imaging methods. 3DCR, therefore, complements traditional 2-dimensional and 3-dimensional imaging methods and serves as an emerging tool for neuroimagers to communicate with and educate other clinicians.