Denise Brunozzi

Validation of cerebral arteriovenous malformation hemodynamics assessed by DSA using quantitative magnetic resonance angiography: preliminary study

Background The hemodynamic evaluation of cerebral arteriovenous malformations (AVMs) using DSA has not been validated against true flow measurements. Objective To validate AVM hemodynamics assessed by DSA using quantitative magnetic resonance angiography (QMRA). Materials and methods Patients seen at our institution between 2007 and 2016 with a supratentorial AVM and DSA and QMRA obtained before any treatment were retrospectively reviewed. DSA assessment of AVM flow comprised AVM arterial-to-venous time (A-Vt) and iFlow transit time. A-Vt was defined as the difference between peak contrast intensity in the cavernous internal carotid artery and peak contrast intensity in the draining vein. iFlow transit times were determined using syngo iFlow software. A-Vt and iFlow transit times were correlated with total AVM flow measured using QMRA and AVM angioarchitectural and clinical features. Results 33 patients (mean age 33 years) were included. Nine patients presented with hemorrhage. Mean AVM volume was 9.8 mL (range 0.3–57.7 mL). Both A-Vt (r=−0.47, p=0.01) and iFlow (r=−0.44, p=0.01) correlated significantly with total AVM flow. iFlow transit time was significantly shorter in patients who presented with seizure but A-Vt and iFlow did not vary with other AVM angioarchitectural features such as venous stenosis or hemorrhagic presentation. Conclusions A-Vt and iFlow transit times on DSA correlate with cerebral AVM flow measured using QMRA. Thus, these parameters may be used to indirectly estimate AVM flow before and after embolization during angiography in real time.

Middle cerebral artery pressure changes following Pipeline flow diversion

Objective Pipeline embolization devices (PED) are commonly used for endovascular treatment of cerebral aneurysms but changes in intracranial hemodynamics after PED deployment are poorly understood. Here, we assess middle cerebral artery (MCA) and systemic blood pressure before and after PED treatment. Methods Records of patients with cerebral aneurysms proximal to the internal carotid artery terminus treated with PED at our institution between 2015 and 2017 were retrospectively reviewed. Patients were included if ipsilateral MCA pressure measurements were available. Ipsilateral MCA pressure was transduced via the microcatheter before and after PED deployment. Systemic arterial blood pressure was also simultaneously recorded. MCA, systemic blood pressure, and ratios of MCA to systemic blood pressure values were compared before and after treatment among the study cohort using the two-sample paired Student t test. Results Fourteen patients were included. Mean age was 54 years. Among the entire cohort, the ratio of MCA to systemic systolic and mean blood pressure were significantly higher after treatment (respectively 0.76 vs. 0.69, p = 0.01, and 0.94 vs. 0.89, p = 0.03), and the ratio of MCA to systemic diastolic pressures showed an increasing trend (1.08 vs. 1.03, p = 0.09). The percentage of ratio increase was independent of aneurysm size (r = –0.24, p = 0.42 for systolic ratio; r = –0.09, p = 0.74 for diastolic ratio; r = –0.09; p = 0.76 for mean ratio, respectively). Conclusions Following PED deployment, the ratio of ipsilateral MCA to systemic systolic and mean blood pressure increased. These pressure changes should be further evaluated in a larger sample size.

Ruptured posterior cerebral artery aneurysm presenting with a contralateral cranial nerve III palsy: A case report

Background: Posterior cerebral artery aneurysms can frequently present with an ipsilateral cranial nerve III palsy. Case Description: We report the first case of a posterior cerebral artery aneurysm associated with a contralateral cranial nerve III palsy. A 64-year-old male presented with acute subarachnoid hemorrhage, Hunt and Hess grade 3, and a left-sided fixed and dilated pupil. Computed tomography scan showed hemorrhage, mainly within the left basal cisterns. Digital subtraction angiography revealed a right-sided P1–P2 junction aneurysm. Conclusions: This case demonstrates that, although the neurological exam can help pinpoint the location of a lesion, false localizing signs should be recognized.

Role of Immersive Touch Simulation in Neurosurgical Training

Over years, neurosurgical training is changing: sophisticated clinical skills to learn are challenged by catastrophic consequences in case of surgical mistakes, and patient safety and procedure efficacy have a higher priority than educational training. Practice, though, is the mainstay for surgical learning and skills improvement, and simulation models provide training opportunity in a safe and controlled environment.

NeuroVR™ Simulator in Neurosurgical Training

In an era where neurosurgical training must counterbalance work-hours restrictions and patient safety with highly sophisticated technical mastery, virtual reality (VR) simulation offers a viable educational alternative to the Halstedian apprenticeship model in a risk-free environment. Furthermore, residency training is moving toward the use of proficiency performance benchmarks to acquire a minimum competency standard.

Contrast Time-Density Time on Digital Subtraction Angiography Correlates With Cerebral Arteriovenous Malformation Flow Measured by Quantitative Magnetic Resonance Angiography, Angioarchitecture, and Hemorrhage

BACKGROUND Digital subtraction angiography (DSA) currently provides angioarchitectural features of cerebral arteriovenous malformations (AVMs) but its role in the hemodynamic evaluation of AVMs is poorly understood. OBJECTIVE To assess contrast time‐density time (TT) on DSA relative to AVM flow measured using quantitative magnetic resonance angiography (QMRA). METHODS Patients seen at our institution between 2007 and 2014 with a supratentorial AVM and DSA and QMRA obtained prior to any treatment were retrospectively reviewed. Regions of interest were selected on the draining veins at the point closest to the nidus. TT on DSA was defined as time needed for contrast to change image intensity from 10% to 100%, 100% to 10%, and 25% to 25%. TT was correlated to AVM total flow, angioarchitectural features, and hemorrhage. RESULTS Twenty‐eight patients (mean age 35.6 yr) were included. Six patients presented with hemorrhage. Mean AVM volume was 11.42 mL (range 0.3‐57.7 mL). Higher total AVM flow significantly correlated with shorter TT100%‐10% and TT25%‐25% (P = .02, .02, respectively). Presence of venous stenosis correlated significantly with shorter TT100%‐10% (P = .04) and TT25%‐25% (P = .04). AVMs with a single draining vein exhibited longer TT25%‐25% compared to those with multiple draining veins (P = .04). Ruptured AVMs had significantly shorter TT10%‐100% compared to unruptured AVMs (P = .05). CONCLUSION TT on DSA correlates with cerebral AVM flow measured using QMRA and with AVM angioarchitecture and hemorrhagic presentation. Thus, TT may be used to indirectly estimate AVM flow during angiography in real‐time and may also be an indicator of important AVM characteristics associated with outflow resistance and increased rupture risk, such as venous stenosis.

Cerebral Aneurysm Size and Distal Intracranial Hemodynamics: An Assessment of Flow and Pulsatility Index Using Quantitative Magnetic Resonance Angiography

BACKGROUND The relationship between cerebral aneurysm size and risk of rupture is well documented, but the impact of aneurysms on distal intracranial hemodynamics is unknown. OBJECTIVE To examine the relationship between aneurysm size and distal intracranial hemodynamics prior to treatment. METHODS Patients seen at our institution between 2006 and 2015 with cerebral aneurysms within the internal carotid artery (ICA) segments (proximal to ICA terminus) were retrospectively reviewed. Patients were included if the aneurysm was unruptured, and were excluded if a contralateral aneurysm was present. Flows within bilateral ICAs and middle cerebral arteries (MCA) were measured prior to any treatment using quantitative magnetic resonance angiography. Pulsatility index (PI = [systolic - diastolic flow velocity]/mean flow velocity) within each vessel was then calculated. Hemodynamic parameters were analyzed with respect to aneurysm size. RESULTS Forty-two patients were included. Mean aneurysm size was 13.5 mm (range 2-40 mm). There was a significant correlation between aneurysm size and ipsilateral MCA PI (P = .006; r = 0.441), MCAipsilateral/ICAipsilateral PI ratio (P = .003; r = 0.57), and MCAipsilateral/MCAcontralateral PI ratio (P = .008; r = 0.43). Mean PI in the ipsilateral ICA was 0.38 (range 0.17-0.77) and ipsilateral MCA was 0.31 (range 0.08-0.83), and mean PI in contralateral ICA was 0.35 (range 0.19-0.57) and MCA was 0.30 (range 0.07-0.89). CONCLUSION Larger aneurysm size correlates with higher ipsilateral MCA PI, demonstrating that aneurysms affect distal intracranial hemodynamics.

Intracranial contrast transit times on digital subtraction angiography decrease more in patients with delayed intraparenchymal hemorrhage after Pipeline

Background Pipeline embolization devices (PEDs) are used for endovascular treatment of cerebral aneurysms but can be associated with delayed ipsilateral intraparenchymal hemorrhage (DIPH). Changes in intracranial hemodynamics after PED are poorly understood. Objective Here, we assess hemodynamic changes after PED in patients and compare these changes in patients with and without DIPH (DIPH+ and DIPH–). Methods Records of patients with distal internal carotid artery (ICA) aneurysms treated with PED at our institution between 2012 and 2017 were retrospectively reviewed. Regions of interest were selected proximally to PED over the cavernous ICA and distally over the middle cerebral artery (MCA), and then transit times were determined using syngo iFlow software (Siemens). Ratio of MCA to ICA transit time was compared before, after treatment, and at follow-up. Ratios were also compared between DIPH+ and DIPH– subgroups. Correlations between aneurysm size, age, and ratios were investigated. Results Fifty-three patients were included. The ratio of MCA to ICA transit time decreased significantly after PED deployment (1.13 vs. 1.22, p < 0.01). The ratio in the DIPH + subgroup (n = 4) was significantly lower (1.00 vs. 1.14, p = 0.01) and decreased significantly more (21% vs. 4.4%, p = 0.02) compared to the DIPH– subgroup (n = 49). The ratio tended to be higher in larger aneurysms at baseline (r = 0.25, p = 0.07) but not after PED treatment (r = 0.11, p = 0.15). Age did not correlate with ratio. Conclusion The ratio of MCA to ICA transit time decreases following PED treatment and decreases more in patients with DIPH. These contrast transit time changes can be detected in real time immediately after PED deployment.

Transorbital Glue Embolization of a Recurrent Venous Varix Using Real-Time Image Guidance in the Neuroangiography Suite

Orbital lesions are challenging to access due to their location amid critical anatomic structures. Here, we demonstrate direct transorbital cannulation of an orbital venous varix using image guidance. A 36-year-old male was diagnosed with a left orbital venous varix approximately 5 years ago at an outside institution. He subsequently underwent surgery for direct intraoperative embolization of the venous varix followed by surgical resection. The patient recently presented to us with left eye pain, proptosis, double vision, and conjunctival hemorrhage precipitated by straining or lying flat. Orbital magnetic resonance imaging showed recurrence of the venous varix, which was then confirmed with digital subtraction angiography and intraprocedural computed tomography (DynaCT, Siemens Healthineers, Erlangen, Germany). Due to scarring from the previous surgery, percutaneous transorbital embolization of the venous varix was planned. The needle trajectory was determined and also visualized in real-time using image guidance (Needle Guidance, Siemens Healthineers). Once the needle reached the desired target, n-butyl cyanoacrylate glue (Codman Neuro, San Jose, California) was injected until nearly the entire venous varix was occluded. There were no complications, and at his postoperative visit the patient reported resolution of all symptoms.

Middle cerebral artery flow velocity increases more in patients with delayed intraparenchymal hemorrhage after Pipeline

Objective Pipeline Embolization Devices (PED) are commonly used for endovascular treatment of cerebral aneurysms but can be associated with delayed ipsilateral intraparenchymal hemorrhage (DIPH). The role that altered intracranial hemodynamics may play in the pathophysiology of DIPH is poorly understood. We assess middle cerebral artery (MCA) flow velocity changes after PED deployment. Materials and methods Patients with aneurysms located proximal to the internal carotid artery terminus treated with PED at our institution between 2015 and 2016 were retrospectively reviewed. Patients were included if MCA flow velocities were measured using transcranial Doppler. Bilateral MCA flow velocities, ratio of ipsilateral to contralateral MCA flow velocity, and bilateral MCA pulsatility index before and after PED deployment were assessed. Results 10 patients of mean age 52 years were included. Two patients had DIPH within 48 hours after PED deployment. We observed that these two patients had a higher increase in ipsilateral MCA mean flow velocity after treatment compared with patients without DIPH (39.5% vs 5.5%). Additionally, before PED deployment, patients with DIPH had a higher ipsilateral MCA pulsatility index (1.55 vs 0.98) and a higher ratio of ipsilateral to contralateral MCA mean flow velocity (1.35 vs 1.04). Conclusions After PED, ipsilateral MCA mean flow velocity increases more in patients with DIPH. These flow velocity changes suggest the possible role of altered distal intracranial hemodynamics in DIPH after PED treatment of cerebral aneurysms. Further data are required to confirm this observation.