Ozair Rahman

Aortic Volumetry at Contrast-Enhanced Magnetic Resonance Angiography: Feasibility as a Sensitive Method for Monitoring Bicuspid Aortic Valve Aortopathy.

Objectives Bicuspid aortic valve patients can develop thoracic aortic aneurysms and therefore require serial imaging to monitor aortic growth. This study investigates the reliability of contrast-enhanced magnetic resonance angiography (CEMRA) volumetry compared with 2-dimensional diameter measurements to identify thoracic aortic aneurysm growth. Materials and Methods A retrospective, institutional review board–approved, and Health Insurance Portability and Accountability Act–compliant study was conducted on 20 bicuspid aortic valve patients (45 ± 8.9 years, 20% women) who underwent serial CEMRA with a minimum imaging follow-up of 11 months. Magnetic resonance imaging was performed at 1.5 T with electrocardiogram-gated, time-resolved CEMRA. Independent observers measured the diameter at the sinuses of Valsalva (SOVs) and mid ascending aorta (MAA) as well as ascending aorta volume between the aortic valve annulus and innominate branch. Intraobserver/interobserver coefficient of variation (COV) and intraclass correlation coefficient (ICC) were computed to assess reliability. Growth rates were calculated and assessed by Student t test (P < 0.05, significant). The diameter of maximal growth (DMG), defined as the diameter at SOV or MAA with the faster growth rate, was recorded. Results The mean time of follow-up was 2.6 ± 0.82 years. The intraobserver COV was 0.01 for SOV, 0.02 for MAA, and 0.02 for volume (interobserver COV: 0.02, 0.03, 0.04, respectively). The ICC was 0.83 for SOV, 0.86 for MAA, 0.90 for DMG, and 0.95 for volume. Average aortic measurements at baseline and (follow-up) were 42 ± 3 mm (42 ± 3 mm, P = 0.11) at SOV, 46 ± 4 mm (47 ± 4 mm, P < 0.05) at MAA, and 130 ± 23 mL (144 ± 24 mL, P < 0.05). Average size changes were 0.2 ± 0.6 mm/y (1% ± 2%) at SOV, 0.5 ± 0.8 mm/y (1% ± 2%) at MAA, 0.7 ± 0.7 mm/y (2% ± 2%) at DMG, and 6 ± 3 mL/y (4% ± 3%) with volumetry. Conclusions Three-dimensional CEMRA volumetry exhibited a larger effect when examining percentage growth, a better ICC, and a marginally lower COV. Volumetry may be more sensitive to growth and possibly less affected by error than diameter measurements.

Accelerated dual‐venc 4D flow MRI for neurovascular applications

To improve velocity‐to‐noise ratio (VNR) and dynamic velocity range of 4D flow magnetic resonance imaging (MRI) by using dual‐velocity encoding (dual‐venc) with k‐t generalized autocalibrating partially parallel acquisition (GRAPPA) acceleration.

Endovascular Management of Pediatric High-Flow Vertebro-Vertebral Fistula with Reversed Basilar Artery Flow: A Case Report and Review of the Literature

Vertebral artery arteriovenous fistula (VAVF) is mostly known as a post-traumatic and/or iatrogenic arteriovenous complication. However, spontaneous high-flow VAVF associated with flow reversal in the basilar artery has not been reported in children. We describe a unique asymptomatic presentation of a spontaneous high-flow VAVF associated with flow reversal in the basilar artery in a pediatric patient. The literature for classification, pathophysiology, treatment strategies, and post-procedural complications is also reviewed.

Perioperative evaluation of regional aortic wall shear stress patterns in patients undergoing aortic valve and/or proximal thoracic aortic replacement

Objectives: To assess in patients with aortopathy perioperative changes in thoracic aortic wall shear stress (WSS), which is known to affect arterial remodeling, and the effects of specific surgical interventions. Methods: Presurgical and postsurgical aortic 4D flow MRI were performed in 33 patients with aortopathy (54 ± 14 years; 5 women; sinus of Valsalva (d_SOV)/midascending aortic (d_MAA) diameters = 44 ± 5/45 ± 6 mm) scheduled for aortic valve (AVR) and/or root (ARR) replacement. Control patients with aortopathy who did not have surgery were matched for age, sex, body size, and d_MAA (n = 20: 52 ± 14 years; 3 women; d_SOV/d_MAA = 42 ± 4/42 ± 4 mm). Regional aortic 3D systolic peak WSS was calculated. An atlas of WSS normal values was used to quantify the percentage of at‐risk tissue area with abnormally high WSS, excluding the area to be resected/graft. Results: Peak WSS and at‐risk area showed low interobserver variability (≤0.09 [−0.3; 0.5] Pa and 1.1% [−7%; 9%], respectively). In control patients, WSS was stable over time (follow‐up–baseline differences ≤0.02 Pa and 0.0%, respectively). Proximal aortic WSS decreased after AVR (n = 5; peak WSS difference ≤−0.41 Pa and at‐risk area ≤−10%, P < .05 vs controls). WSS was increased after ARR in regions distal to the graft (peak WSS difference ≥0.16 Pa and at‐risk area ≥4%, P < .05 vs AVR). Follow‐up duration had no significant effects on these WSS changes, except when comparing ascending aortic peak WSS between ARR and AVR (P = .006). Conclusions: Serial perioperative 4D flow MRI investigations showed distinct patterns of postsurgical changes in aortic WSS, which included both reductions and translocations. Larger longitudinal studies are warranted to validate these findings with clinical outcomes and prediction of risk of future aortic events.

4D flow MRI demonstrates changes in cardiovascular haemodynamics in complex congenital heart disease

An 8-month-old female with heterotaxy syndrome, single ventricle physiology, double outlet right ventricle, mitral atresia, total anomalous pulmonary venous connection to the coronary sinus, an interrupted inferior vena cava with azygous continuation to the superior vena cava, and post pulmonary artery banding underwent a Kawashima palliative procedure. Seven months …

Spatio-temporal visualization of regional myocardial velocities

Cardiovascular disease is the leading cause of death worldwide according to the World Health Organization (WHO). Nearly half of all heart failures occur due to the decline in the performance of the left ventricle (LV). Therefore, early detection, monitoring, and accurate diagnosis of LV pathologies are of critical importance. Usually, global cardiac function parameters are used to assess the cardiac structure and function, although regional abnormalities are important biomarkers of several cardiac diseases. Regional motion of the myocardium, the muscular wall of the LV, can be captured in a non-invasive manner using the velocity-encoded magnetic resonance (MR) imaging method known as Tissue Phase Mapping (TPM). To analyze the complex motion pattern, one typically visualizes for each time step the radial, longitudinal, and circumferential velocities separately according to the American Heart Association (AHA) model, which makes the comprehension of the spatio-temporal pattern an extremely challenging cognitive task. We propose novel spatio-temporal visualization methods for LV myocardial motion analysis with less cognitive load. Our approach uses coordinated views for navigating through the data space. One view visualizes individual time steps, which can be scrolled or animated, while a second view visualizes the temporal evolution using the radial layout of a polar plot for the time dimension. Different designs for visual encoding were considered in both views and evaluated with medical experts to demonstrate and compare their effectiveness and intuitiveness for detecting and analyzing regional abnormalities.

O-023 Characteristics and Outcomes of Acute Ischaemic Stroke Patients Selected and Excluded for Intra-arterial Intervention by Perfusion Imaging

Background/Purpose Perfusion imaging has been proposed as an effective modality in selecting acute ischaemic stroke (AIS) patients who may benefit from intra-arterial (IA) intervention. We investigated the characteristics and outcomes of patients that were deemed ineligible for IA intervention based on perfusion imaging as compared to those who underwent intervention at our institution. Materials and Methods A multicentre retrospective review of all AIS patients who underwent perfusion imaging from February 2010 to August 2012 was conducted. Inclusion criteria were the following: symptom-onset to presentation ≤8 hours, anterior circulation large vessel occlusion as determined by CT/MR angiography (MCA/ICA occlusions), baseline National Institute of Health Stroke Scale (NIHSS) score ≥8. Patients selected or excluded for IA intervention based on CT/MR perfusion imaging profiles (CBV/DWI infarct core < 1/3 MCA territory and mismatch of ischaemic penumbra > 20% infarct core) were separated into subgroups for analysis. Patient demographics, cardiac and stroke risk factors, intravenous (IV) tPA utilisation, location of occlusion, time from symptom-onset to presentation, NIHSS and modified Rankin Scores (mRS) scores (baseline, discharge, and 90 days), duration of hospital stay, discharge disposition (home, rehabilitation/nursing home, hospice), and mortality rates were recorded. Good functional outcome was defined as mRS 0–2 at 90 days. Statistical analyses were performed with SPSS 20.0. Results 110 eligible AIS patients underwent perfusion imaging of which 62 were excluded from IA intervention (56.4%) based on CT/MR perfusion imaging profiles. Table 1 details patient characteristics and outcomes in the intervention versus non-intervention subgroups. Abstract O-023 Table 1 Non- Intervention Intervention p Value n=62 n=48 Mean age (yrs) 80.87 74.19 0.04* Female (%) 40 (64.5%) 29 (60.4%) 0.89 Mean time-symptom onset to presentation (min) 166.84 249.35 0.03* Transfer from outside institution 0 10 (20.1%) 0.03* Mean baseline NIHSS 19.35 18.67 0.74 Mean NIHSS at discharge 13.43 9.80 0.02* IV tPA (%) 40 (64.5%) 20 (41.7%) 0.04* Mean duration of hospital stay (d) 5.39 8.44 0.16 Risk factors Atrial fibrillation 33 (53.2%) 14 (29.2%) 0.04* DM 14 (22.6%) 17 (35.4%) 0.21 Hyperlipidemia 28 (45.2%) 18 (37.5%) 0.23 HTN 52 (83.9%) 12 (25.0%) 0.03* Smoking 2 (3.2%) 7 (14.6%) 0.05 Discharge disposition Home (%) 2 (3.2%) 9 (18.8%) 0.001* Rehabilitation/Nursing home (%) 26 (54.8%) 20 (41.6%) 0.85 Hospice/Mortality (%) 34 (42.0%) 19 (39.6%) 0.87 Good functional outcome at 90-days (%) 20 (35.7%) 32 (66.7%) 0.001* Conclusions Among a large cohort eligible for intervention, perfusion mismatch was present in younger patients with fewer vascular risk factors. These data suggest that advanced age and atherosclerotic risk factors may influence rate of progression from ischaemia to infarction through decreased cerebrovascular reserve and collateral flow in response to arterial occlusion. Despite earlier time to presentation (imaging) and greater receipt of IV tPA, those without perfusion mismatch were deemed futile for IA intervention, six-fold less likely to be discharged to home, and half as likely to have independent functional outcomes. However, nearly one-third of non-intervention patients achieved functional independence at 3 months suggesting the need to refine patient selection strategies for IA intervention. Disclosures M. Soltanolkotabi: None. F. Feiz: None. C. Beck: None. O. Rahman: None. A. Shaibani: None. M. Hurley: None. S. Prabhakaran: None. S. Ansari: None.

O-021 Evaluation of Baseline CT ASPECTS in Perfusion-guided Selected Patients for Intra-arterial Reperfusion Therapy

Background and Purpose Appropriate patient selection in acute ischaemic stroke (AIS) is central for improving patient outcomes following intra-arterial (IA) reperfusion therapy (thrombolysis/mechanical thrombectomy). Perfusion imaging with CTP/MR DWI-PWI has been utilised increasingly to identify subpopulations with acceptable risk-benefit profiles for reperfusion, avoiding futile or harmful recanalisation. Earlier studies reported to have prognostic value of baseline Alberta Stroke Program Early CT Score (ASPECTS) of >7 in determining good functional outcomes following IA reperfusion. We investigated baseline CT ASPECTS in AIS patients selected for IA reperfusion therapy based on perfusion mismatch profiles. Furthermore, we studied the predictive value of CT ASPECTS for clinical outcomes following recanalisation. Materials and Methods In a multicentre review, all AIS patients that underwent IA thrombolysis/thrombectomy between January 2010 and September 2012 were studied retrospectively for the following inclusion criteria: baseline NIHSS >8, presentation <8 hours from symptom onset, CTA/MRA verified M1-M2 MCA occlusion, and favourable perfusion (CTP/MR DWI-PWI) mismatch profile. Patient demographics, medical comorbidities, time from symptom onset to recanalisation, final recanalisation (TICI scale), and clinical outcomes (90 day mRS score) were obtained. One neuroradiologist conducted blinded scoring of ASPECTS for all baseline noncontrast CT scans. For evaluation of inter-rater reliability, scores by another neuroradiologist were used and analysed using Intraclass Correlation Coefficient (ICC) and Bland and Altman method. ASPECTS scores were dichotomised into >7 and ≤7 for primary analysis. Chi-square, Mann-Whitney U and student t tests were used for univariate analyses as appropriate. To obtain the optimal cut-off ASPECTS for discriminating patients with favourable outcomes, receiver operating characteristic (ROC) curve analysis was performed. Results Seventy-one consecutive patients (39 female/32 male patients with mean age of 71.2 ± 15.5 years) met inclusion criteria for analysis. Successful recanalisation (TICI > 2b/3) was achieved in 38 patients (53.5%), highly correlating with good functional outcomes (mRS 0–2) in 43 patients (60.6%) (P < 0.001). No significant difference was observed between ASPECTS reading (P=0.9) with good inter-rater reliability (ICC=0.80, 95% confidence interval: 0.66 to 0.87). Patients with ASPECTS >7 (n=43) and ≤7 (n=28) were comparable in baseline characteristics,medical history, and treatment related variables (age, P=0.8; sex, P=0.8; baseline NIHSS score, P=0.2; diabetes, P=0.8; atrial fibrillation, P=1.0; hyperlipidemia, P=1.0; hypertension, P=0.8; recanalisation, P=0.6; time from symptom onset to recanalisation, P=0.7). Relatively high ASPECTS correlated with perfusion-based patient selection with mean and median baseline ASPECTS of eight. However, no significant correlation was observed between baseline ASPECTS and final clinical outcomes (P=0.5). Additionally, baseline ASPECTS score >7 did not correlate with final outcome in patients with successful recanalisation (P=0.4). The ROC curve analysis demonstrated a cut-off point of eight for discrimination of final outcome, but with poor predictive value (sensitivity=65.1%; specificity=28.6%; P=0.8, AUC=0.51). Conclusion Our results indicate favourable baseline CT ASPECTS correlate with favourable perfusion mismatch profiles and may represent an equivalent surrogate for primary patient selection in IA reperfusion therapy. However, CT ASPECTS did not clearly predict good functional outcomes independent of recanalisation, suggesting other confounding variables such as core infarct volume versus eloquence may impact clinical outcomes and have to be elucidated. Disclosures A. Honarmand: None. M. Soltanolkotabi: None. S. Prabhakaran: None. M. Hurley: None. O. Rahman: None. A. Shaibani: None. S. Ansari: None.