Preoperative embolization and internal carotid artery coil sacrifice in a case of juvenile nasopharyngeal angiofibroma
Interpretation Errors in CT Angiography of the Head and Neck and the Benefit of Double Reading
http://www.ajnr.org/content/32/11/2132.abstract
Interpretation Errors in CT Angiography of the Head and Neck and the Benefit of Double Reading
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Monitoring Embolized Brain Aneurysms Without radiation or contrast
researchers from the University of British Columbia have discovered an interesting property of the platinum embolism implant – it can act as a fairly accurate sensor and antenna. The reason is simply that the implant’s coiled shape causes its material properties, namely its resonance frequency, to vary depending on the blood flow through it. A simple handheld RF reader is all that would be required to monitor the status of the embolization-coil sensor.
Department of Electrical & Computer Engineering, University of British Columbia, 2332 Main Mall, Vancouver, BC, V6T 1Z4 Canada. The rupture of a cerebral aneurysm is the most common cause of subarachnoid hemorrhage. Endovascular embolization of the aneurysms by implantation of Guglielmi detachable coils (GDC) has become a major treatment approach in the prevention of a rupture. Implantation of the coils induces formation of tissues over the coils, embolizing the aneurysm. However, blood entry into the coiled aneurysm often occurs due to failures in the embolization process. Current diagnostic methods used for aneurysms, such as X-ray angiography and computer tomography, are ineffective for continuous monitoring of the disease and require extremely expensive equipment. Here we present a novel technique for wireless monitoring of cerebral aneurysms using implanted embolization coils as radiofrequency resonant sensors that detect the blood entry. The experiments show that commonly used embolization coils could be utilized as electrical inductors or antennas. As the blood flows into a coil-implanted aneurysm, parasitic capacitance of the coil is modified because of the difference in permittivity between the blood and the tissues grown around the coil, resulting in a change in the coil's resonant frequency. The resonances of platinum GDC-like coils embedded in aneurysm models are detected to show average responses of 224-819MHz/ml to saline injected into the models. This preliminary demonstration indicates a new possibility in the use of implanted GDC as a wireless sensor for embolization failures, the first step toward realizing long-term, noninvasive, and cost-effective remote monitoring of cerebral aneurysms treated with coil embolization.Radio aneurysm coils for noninvasive detection of cerebral embolization failures: A preliminary study.
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Accuracy of On-Call Resident Interpretation of CT Angiography for Intracrani...
While radiology residents are pretty good in reporting in general, they lack the skills in vascular imaging and neuroradiology in general.
OBJECTIVE. The purpose of this article is to evaluate the accuracy of preliminary on-call radiology resident interpretation of CT angiography (CTA) compared with digital subtraction angiography (DSA) in detecting cerebral aneurysms in subarachnoid hemorrhage (SAH).
MATERIALS AND METHODS. A retrospective review compared resident interpretations of head CTA performed after hours for SAH to the results of DSA. The sensitivity and specificity of resident interpretations were classified on a per-patient and per-aneurysm basis. The accuracy of resident interpretations was also determined according to aneurysm location and number.
RESULTS. Between January 2007 and December 2009, 83 patients with SAH underwent both CTA and DSA. DSA documented an aneurysm in 53 of 83 patients. Per patient, residents identified at least one aneurysm in 46 of 53 patients (87%). Per aneurysm, resident sensitivity and specificity for detecting aneurysms of any size were 62% and 91%, respectively, which improved for aneurysms 3 mm or larger to 73% and 97%, respectively. The posterior communicating and intracranial internal carotid arteries were resident "blind spots," with aneurysms 3 mm or larger detected with sensitivities of 33% and 50%, respectively. In contrast, anterior communicating artery aneurysms were correctly identified 95% of the time. In only 35% of cases with multiple aneurysms did residents correctly identify more than one aneurysm.
CONCLUSION. The sensitivity of on-call resident interpretation of CTA for aneurysms in SAH is lower than expected, with a potential for delay in diagnosis and management in a small number of patients. Focused training to carefully review apparent blind spots and the frequency of multiple aneurysms may reduce inaccuracies.
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Cerebral Perfusion Long Term after Therapeutic Occlusion of the Internal Carotid Artery in Patients Who Tolerated Angiographic Balloon Test Occlusion
Cerebral Perfusion Long Term after Therapeutic Occlusion of the Internal Carotid Artery in Patients Who Tolerated Angiographic Balloon Test Occlusion
Gevers, S., Heijtel, D., Ferns, S. P., van Ooij, P., van Rooij, W. J., van Osch, M. J., van den Berg, R., Nederveen, A. J., Majoie, C. B.
Therapeutic carotid occlusion is an established technique for treatment of large and giant aneurysms of the ICA, in patients with synchronous venous filling on angiography during BTO. Concern remains that hemodynamic alterations after permanent occlusion will predispose the patient to new ischemic injury in the ipsilateral hemisphere. The purpose of this study was to assess whether BTO with synchronous venous filling is associated with normal CBF long term after carotid sacrifice.
MATERIALS AND METHODS:Eleven patients were included (all women; mean age, 50.5 years; mean follow-up, 38.5 months). ASL with single and multiple TIs was used to assess CBF and its temporal characteristics. Selective ASL was used to assess actual territorial contribution of the ICA and BA. Collateral flow via the AcomA or PcomA or both was determined by time-resolved 3D PCMR. Paired t tests were used to compare CBF and timing parameters between hemispheres.
RESULTS:Absolute CBF values were within the normal range. There was no significant CBF difference between hemispheres ipsilateral and contralateral to carotid sacrifice (49.4 ± 11.2 versus 50.1 ± 10.1 mL/100 g/min). Arterial arrival time and trailing edge time were significantly prolonged on the occlusion side (816 ± 119 ms versus 741 ± 103 ms, P = .001; and 1765 ± 179 ms versus 1646 ± 190 ms, P < .001). Two patients had collateral flow through the AcomA only and were found to have increased timing parameters compared with 9 patients with mixed collateral flow through both the AcomA and PcomA.
CONCLUSIONS:In this small study, patients with synchronous venous filling during BTO had normal CBF long term after therapeutic ICA occlusion.
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Regional Leptomeningeal Score on CT Angiography Predicts Clinical and Imaging Outcomes in Patients with Acute Anterior Circulation Occlusions
In this article from Alberta, an objective scoring system with clincal correlation has been published and is welcome. It should pave the path for better non-invasive assessment of the patient.
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