Automated vs. manual coding of neuroimaging reports via natural language processing, using the international classification of diseases, tenth revision.

Objective: Natural language processing (NLP) can generate diagnoses codes from imaging reports. Meanwhile, the International Classification of Diseases (ICD-10) codes are the United States' standard for billing/coding, which enable tracking disease burden and outcomes. This cross-sectional study aimed to test feasibility of an NLP algorithm's performance and comparison to radiologists' and physicians' manual coding. Methods: Three neuroradiologists and one non-radiologist physician reviewers manually coded a randomly-selected pool of 200 craniospinal CT and MRI reports from a pool of >10,000. The NLP algorithm (Radnosis, VEEV, Inc., Minneapolis, MN) subdivided each report's Impression into "phrases", with multiple ICD-10 matches for each phrase. Only viewing the Impression, the physician reviewers selected the single best ICD-10 code for each phrase. Codes selected by the physicians and algorithm were compared for agreement. Results: The algorithm extracted the reports' Impressions into 645 phrases, each having ranked ICD-10 matches. Regarding the reviewers' selected codes, pairwise agreement was unreliable (Krippendorff α = 0.39-0.63). Using unanimous reviewer agreement as "ground truth", the algorithm's sensitivity/specificity/F2 for top 5 codes was 0.88/0.80/0.83, and for the single best code was 0.67/0.82/0.67. The engine tabulated "pertinent negatives" as negative codes for stated findings (e.g. "no intracranial hemorrhage"). The engine's matching was more specific for shorter than full-length ICD-10 codes (p = 0.00582x10-3). Conclusions: Manual coding by physician reviewers has significant variability and is time-consuming, while the NLP algorithm's top 5 diagnosis codes are relatively accurate. This preliminary work demonstrates the feasibility and potential for generating codes with reliability and consistency. Future works may include correlating diagnosis codes with clinical encounter codes to evaluate imaging's impact on, and relevance to care.

Percutaneous n-butyl cyanoacrylate embolization of cervical metastatic disease via an anterolateral approach.

Symptomatic vascular spinal metastases will benefit from pre-operative tumor embolization - percutaneous with or without adjunct endovascular embolization. However, when a transpedicular approach is not feasible, an anterolateral approach may be a viable alternative. The authors report a 57-year-old woman with prior C3-T1 instrumentation who presented with acute cord compression from a pathologic C5 vertebral body fracture related to metastatic renal cell carcinoma. The patient underwent CT-guided direct tumor embolization with 33% n-butyl-2-cyanoacrylate via an anterolateral approach, followed by C5-corpectomy and anterior cervical C4-C6 fusion and plating with minimal blood loss (est. 20 cc) and a stable neurological exam post-operatively. In patients with highly vascular cervical metastatic disease who lack a viable transpedicular approach for preoperative tumor embolization, a CT-guided anterolateral approach is a viable alternative.

Use of reverse angle guide catheter with trans-radial approach in patients undergoing middle meningeal artery embolization.

Background: Trans-radial access (TRA) for MMA embolization has grown due to lower access site complications and greater patient satisfaction. Here, we describe the feasibility of utilizing a 6F Envoy Simmons 2 (6F-SIM2) as a guide catheter with TRA and compare outcomes with trans-femoral approach (TFA) in a single center case series. Methods: We performed a retrospective review of patients who underwent MMA embolization for management of chronic subdural hematoma (cSDH). TRA was performed by utilizing a combination of 6F 90cm Envoy (Codman & Shurtleff, Inc., Rayham, MA) Simmons 2 guide catheter and 5F 125cm Sofia (Microvention, Aliso Viejo, CA) intermediate catheter. Outcomes measured are Modified Rankin Score (mRS) at 90 days, inpatient mortality, post-embolization recurrence, fluoroscopy time and radiation exposure. Results: A total of 71 patients underwent 97 MMA embolization overall with 65 (67%) in trans-femoral access group, 11 (11.3%) in trans-radial access without use of Simmons 2 Guide catheter group and 21 (21.6%) in trans-radial access with use of Simmons 2 Guide catheter group. There were no direct access-related complications in either group. One patient had thromboembolic stroke in trans-femoral group. There was no difference in average procedure-related total fluro time or radiation dose among all three groups. Conclusion: Trans-radial approach using 6F-SIM2 guide catheter coupled with 5F Sofia intermediate catheter is safe and effective. It provides an alternative approach to access distal branches of bilateral anterior circulation in elderly patients with difficult anatomy undergoing MMA embolization.

Trans-radial spinal angiography: A single-center experience.

INTRODUCTION: Spinal angiography (SpAn) is the gold standard for diagnosis of spinal dural fistulas and arteriovenous malformations. A complete spinal angiogram necessitates the interrogation of the segmental arteries arising from the aorta at every level as well, the internal iliac; and median sacral arteries at the caudal end; and the cervical vasculature at the cranial end. SpAn has traditionally been performed with transfemoral arterial access and could be challenging. Of late, transradial arterial access has emerged as a popular alternative for endovascular surgical Neuroradiology (ESN) procedures including SpAn. However, there is paucity of the literature regarding transradial access for spinal angiography. METHODS: After IRB approval, records and imaging were reviewed in a series of patients who underwent SpAn at our institution. RESULTS: A total of nine spinal angiograms were performed via transradial access in a consecutive series of eight patients between July 2019 and December 2020 at our institution. Eight of these were diagnostic SpAn's, and one patient underwent SpAn with transradial approach for the treatment of a type I spinal dural arteriovenous fistula. No complications occurred during or subsequent to the procedures. CONCLUSION: SpAn can be successfully and safely accomplished via transradial access. This approach appears to provide a stable method for interventions, as well.

Injectable and Repeatable Inductive Heating of Iron Oxide Nanoparticle-Enhanced "PHIL" Embolic toward Tumor Treatment.

Deep-seated tumors of the liver, brain, and other organ systems often recur after initial surgical, chemotherapeutic, radiation, or focal treatments. Repeating these treatments is often invasive and traumatic. We propose an iron oxide nanoparticle (IONP)-enhanced precipitating hydrophobic injectable liquid (PHIL, MicroVention inc.) embolic as a localized dual treatment implant for nutrient deprivation and multiple repeatable thermal ablation. Following a single injection, multiple thermal treatments can be repeated as needed, based on monitoring of tumor growth/recurrence. Herein we show the ability to create an injectable stable PHIL-IONP solution, monitor deposition of the PHIL-IONP precipitate dispersion by µCT, and gauge the IONP distribution within the embolic by magnetic resonance imaging. Once precipitated, the implant could be heated to reach therapeutic temperatures >8 °C for thermal ablation (clinical temperature of ∼45 °C), in a model disk and a 3D tumor bed model. Heat output was not affected by physiological conditions, multiple heating sessions, or heating at intervals over a 1 month duration. Further, in ex vivo mice hind-limb tumors, we could noninvasively heat the embolic to an "ablative" temperature elevation of 17 °C (clinically 54 °C) in the first 5 min and maintain the temperature rise over +8 °C (clinically a temperature of 45 °C) for longer than 15 min.

Flow residence time in intracranial aneurysms evaluated by in vitro 4D flow MRI.

The process of an intracranial aneurysm development, growth, and rupture is multifaceted and complex. In addition, clinical observations have identified the potential of thrombus formation within such aneurysms. While the underlying mechanism is not fully understood, the thrombi represent a potential risk factor for ischemic stroke. Emerging studies indicate that blood residence time (RT) is a promising hemodynamic metric associated with the aneurysm rupture and formation of intra-aneurysmal thrombi. Here, we present a methodology to experimentally evaluate both trajectory-wise and local RT based on magnetic resonance imaging (MRI) velocimetry, and apply it to in vitro flow measurements in scaled-up replicas of 9 patient-specific intracranial aneurysms. Lagrangian tracks of massless tracers are integrated from the velocity fields and averaged to return the mean RT in the aneurysm sac. This is found to be closely approximated by a simple time scale based on the sac diameter and space-time average of the aneurysmal fluid velocity. The mean RT is also correlated with the inflow time scale at the parent artery. These results also provide a basis for the estimation of RT when high-resolution hemodynamic maps are not available. With the continuous increase in accuracy and resolution enabled by progress in MRI technology, the methodology described here may in the future be applicable to in vivo data.

BOBBY balloon guide catheter thrombectomy in large-vessel occlusion stroke: Initial experience.

BACKGROUND AND PURPOSE: Nonrandomized studies have found Balloon Guide Catheter (BGC) use to improve technical and functional outcomes in patients undergoing mechanical thrombectomy (MT). MATERIALS AND METHODS: We performed a retrospective analysis on prospectively collected data of consecutive ischemic stroke patients undergoing MT at our institution (December 2020-October 2021). Interventions where BOBBY BGC (BBGC, MicroVentionTM, Aliso Viejo, CA) was used were identified. Baseline demographics and clinico-radiographic characteristics were retrospectively collected and analysed using descriptive statistics. RESULTS: A total of 43 patients received BBGC-MT (male: female = 26:17, median age 72 years [IQR 62-82]). The most common occlusion site was the middle cerebral artery (MCA) (60.4%). Over half (51.2%) received intravenous thrombolytics. The BBGC tracked well over tortuous aortic arches (type II 34.8%, type III 16.3%), with median arteriotomy-to-perfusion time of 29 min (IQR 20-46). Thromboaspiration was used as first-line MT technique in 69.7% cases, with 1 (IQR 1-2) median MT pass achieving modified TICI (thrombolysis in cerebral ischemia) scores of 3 and 2b/3 in 74.4% and 95.3% respectively. Our overall first pass effect (FPE, defined as mTICI 3 after firs-pass) and modified FPE (defined as, mTICI 2b/3 after first-pass) rates were 51.1% and 79.1% respectively, with rates of 92.3% and 100% respectively when stentretriever and thromboaspiration were combined. The median reduction in National Institutes of Health Stroke Scale (NIHSS) was 9 (IQR 4-15, p < 0.0001), with a median 90-day modified Rankin Score (mRS) of 1.5 (IQR 0-2). CONCLUSIONS: BOBBY BGC use resulted in a high first-pass effect rate and may contribute towards improved functional outcomes.

Patterns and Predictors of Extra-Corporeal Membrane Oxygenation Related Cerebral Microbleeds.

OBJECTIVES: Recent case-reports have described an atypical cerebral microbleed (CMB) topography after extracorporeal membrane oxygenation (ECMO). The objective of this study was to examine the prevalence, radiographic patterns, and clinical correlates of possibly-ECMO-related (PER) CMB. MATERIALS AND METHODS: We performed a retrospective study of 307 consecutive patients receiving ECMO support at our tertiary-care University Hospital (2013-2018). PER CMB were defined as CMB present in corpus-callosum and/or middle cerebellar peduncle with/without involvement of other lobar/deep structures. Leukoaraiosis was quantified using the Wahlund age-related white matter changes scale. Patient characteristics were compared between cohorts with and without PER CMB. RESULTS: Forty patients (median age 60 years; 33% vv-ECMO and 67% va-ECMO) received at-least one MRI-brain within 3 months of ECMO support. CMB were present in 77.5% (n = 31) patients with 39% (n = 12), 17% (n = 5), and 44% (n = 14) having low (< 10 CMB), moderate (10-30 CMB), and high (> 30 CMB) burden respectively. Among CMB-positive patients, 71% (n = 22) had PER CMB, with 91% of such cases demonstrating involvement of splenium. Leukoaraiosis did not corelate to PER CMB presence (p = 0.267) or burden (ρ = 0.09). Patients with PER CMB had higher rates of ischemic stroke (50 vs. 33%), intracranial hemorrhage (41 vs. 17%), and all-cause mortality (27 vs. 17%); with survivors demonstrating no differences in their discharge disposition or modified Rankin Score. CONCLUSIONS: Post-ECMO cerebral microbleeds have a distinct distribution pattern that commonly involves the splenium of corpus-callosum. Their etiopathogenesis may be independent of microvascular lipohyalinosis. This requires further study in a larger sample-size.

The foramen ovale "mirage" and how this impacts percutaneous cannulation for treatment of trigeminal neuralgia: a report of two cases.

Percutaneous stereotactic radiofrequency rhizotomy (PSR) for trigeminal neuralgia most commonly utilizes 2D fluoroscopy for intraoperative needle guidance into the foramen ovale (FO). We describe two cases in which needle advancement into FO was unachievable despite appropriate needle placement on biplane fluoroscopy. Intraoperative multiplanar reconstruction was helpful in more accurately depicting foraminal anatomy which allowed the manipulation of the tip of the needle, which was followed by successful FO cannulation. We propose that this "mirage" is likely created by the inherent nature of X-ray-based fluoroscopy in which the FO appears to be readily penetrable, when in fact the 3D anatomy actually prevents cannulation.

Scepter-Mini Balloon Assisted Coil Embolization of an Intracranial Arterial Aneurysm in a Child with PHACE Syndrome via a Persistent Trigeminal Artery.

Cerebral vascular malformations constitute one of the key abnormalities in children with PHACE syndrome, which is characterized by Plaque like cutaneous hemangiomas, Posterior fossa abnormalities, arterial Cerebrovascular and Eye abnormalities, with or without Sternal clefts (PHACES when sternal clefts are present), and associated midline anomalies. Both moyamoya arteriopathy and intracranial aneurysms have been reported in children with this syndrome. Herein, we report the successful treatment of a growing left posterior-communicating artery aneurysm arising from an aberrant left internal carotid artery (LICA) with balloon assisted coiling (BAC) in a child with PHACE syndrome. We circumvented the limitations posed by the narrow caliber of the proximal LICA, by successfully navigating a coiling microcatheter from the basilar artery into the LICA via a persistent trigeminal artery. BAC was then achieved using a Scepter Mini balloon microcatheter for aneurysm neck remodelling.

Readmission Trends Related to Unruptured Intracranial Aneurysm Treatment.

Background and Purpose: Aneurysmal subarachnoid hemorrhage (SAH) is associated with high mortality. Prophylactic treatment of the unruptured intracranial aneurysm (UIA) is considered in a select group of patients thought to be at high for aneurysmal rupture. Hospital readmission rates can serve as a surrogate marker for the safety and cost-effectiveness of treatment options for UIAs; we present an analysis of the 30-day rehospitalization rates and predictors of readmission following UIA treatment with surgical and endovascular approaches. Methods: We retrospectively analyzed data from the National Readmission Database (NRD) derived from the Healthcare Cost and Utilization Project for the year 2014. The cohort included patients with a primary discharge diagnosis of a treated unruptured aneurysm. The primary outcome variable was the 30-day readmission rate in open surgical vs. endovascularly treated groups. The secondary outcomes included predictors of readmissions, and causes of 30-day readmissions in these two groups. Results: The 30-day readmission rate for the surgical group was 8.37% compared to 4.87% for the endovascular group. The index hospitalization duration was longer in the surgical group. A larger proportion of the patients readmitted following surgical treatment were hypertensive (76.35, vs. 63.43%), but the prevalence of other medical comorbidities was comparable in the two treatment groups. Conclusions: There is a higher likelihood for 30-day readmission, longer duration of initial hospitalization and a lower likelihood of discharge home following surgical treatment of UIAs when compared to endovascular treatment. These findings, however, do not demonstrate long-term superiority of one specific treatment modality.

Safety of the APOLLO Onyx delivery microcatheter for embolization of brain arteriovenous malformations: results from a prospective post-market study.

BACKGROUND: Catheter retention and difficulty in retrieval have been observed during embolization of brain arteriovenous malformations (bAVMs) with the Onyx liquid embolic system (Onyx). The Apollo Onyx delivery microcatheter (Apollo) is a single lumen catheter designed for controlled delivery of Onyx into the neurovasculature, with a detachable distal tip to aid catheter retrieval. This study evaluates the safety of the Apollo for delivery of Onyx during embolization of bAVMs. METHODS: This was a prospective, non-randomized, single-arm, multicenter, post-market study of patients with a bAVM who underwent Onyx embolization with the Apollo between May 2015 and February 2018. The primary endpoint was any catheter-related adverse event (AE) at 30 days, such as unintentional tip detachment or malfunction with clinical sequelae, or retained catheter. Procedure-related AEs (untoward medical occurrence, disease, injury, or clinical signs) and serious AEs (life threatening illness or injury, permanent physiological impairment, hospitalization, or requiring intervention) were also recorded. RESULTS: A total of 112 patients were enrolled (mean age 44.1±17.6 years, 56.3% men), and 201 Apollo devices were used in 142 embolization procedures. The mean Spetzler-Martin grade was 2.38. The primary endpoint was not observed (0/112, 0%). The catheter tip detached during 83 (58.5%) procedures, of which 2 (2.4%) were unintentional and did not result in clinical sequelae. At 30 days, procedure related AEs occurred in 26 (23.2%) patients, and procedure-related serious AEs in 12 (10.7%). At 12 months, there were 3 (2.7%) mortalities, including 2 (1.8%) neurological deaths, none of which were device-related. CONCLUSION: This study demonstrates the safety of Apollo for Onyx embolization of bAVMs. CLINICAL TRIAL REGISTRATION: CNCT02378883.

CT perfusion core and ASPECT score prediction of outcomes in DEFUSE 3.

BACKGROUND: The role of Alberta Stroke Program Early CT Score (ASPECTS) for thrombectomy patient selection and prognostication in late time windows is unknown. AIMS: We compared baseline ASPECTS and core infarction determined by CT perfusion (CTP) as predictors of clinical outcome in the Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3 (DEFUSE) 3 trial. METHODS: We included all DEFUSE 3 patients with baseline non-contrast CT and CTP imaging. ASPECTS and core infarction were determined by the DEFUSE 3 core laboratory. Primary outcome was functional independence (modified Rankin Scale (mRS) ≤2). Secondary outcomes included ordinal mRS shift at 90 days and final core infarction volume. RESULTS: Of the 142 patients, 85 patients (60%) had ASPECTS 8-10 and 57 (40%) had ASPECTS 5-7. Thirty-one patients (36%) with ASPECTS 8-10 and 11 patients (19%) with ASPECTS 5-7 were functionally independent at 90 days (p = 0.03). In the primary and secondary logistic regression analysis, there was no difference in ordinal mRS shift (p = 0.98) or functional independence (mRS ≤ 2; p = 0.36) at 90 days between ASPECTS 8-10 and ASPECTS 5-7 patients. Similarly, primary and secondary logistic regression analyses found no difference in ordinal mRS shift (p = 1.0) or functional independence (mRS ≤ 2; p = 0.87) at 90 days between patients with baseline small core ( < 50 ml) versus medium core (50-70 ml). CONCLUSIONS: Higher ASPECTS (8-10) correlated with functional independence at 90 days in the DEFUSE trial. ASPECTS and core infarction volume did not modify the thrombectomy treatment effect, which indicates that patients with a target mismatch profile on perfusion imaging should undergo thrombectomy regardless of ASPECTS or core infarction volume in late time windows.

The Rate of Symptomatic Ischemic Events after Passing Balloon Test Occlusion of the Major Intracranial Arteries: Meta-Analysis.

BACKGROUND: Balloon test occlusion is a widely used method for predicting tolerance of vessel occlusion in the treatment of aneurysms, fistulae, and head and neck neoplasms. However, the false-negative rate is variably reported due in part to the diversity of perfusion monitoring methods. OBJECTIVE: To evaluate the rate of symptomatic ischemic events after a negative balloon test occlusion and determine whether perfusion monitoring methods contribute to differences in these rates. METHODS: PubMed was systematically searched for studies between 1990 and 2020 that reported rates of ischemic outcomes of parental vessel occlusion in patients who passed balloon test occlusion. A generalized linear mixed model meta-analysis was performed. Results were expressed as the rate of symptomatic ischemic events after parental vessel occlusion without vessel bypass in patients who passed balloon test occlusion. RESULTS: Thirty-two studies met the inclusion criteria. The overall pooled rate of ischemic events after passing balloon test occlusion was 3.7% (95% confidence interval [CI]: 1.7-7.8). This rate was 3.8% (95% CI: 1.1-12.8) when monitored with angiography, 2.2% (95% CI: 0.4-10.2) when monitored by a form of computed tomography, and 5.3% (95% CI: 1.2-20.4) when monitored by 2 or more methods of perfusion assessment. The complication rate of balloon test occlusion was 0.8% (95% CI: 0.2-2.7). CONCLUSIONS: Balloon test occlusion results in a low rate of subsequent ischemic events, without conclusive evidence of variation between methods of perfusion assessment. The choice of method should focus on reduction of complication risk, experience of the interventional team, and avoidance of prolonged test occlusion times.

The next step in balloon assisted endovascular neurosurgical procedures: A case series of initial experience with the Scepter Mini balloon microcatheter.

BACKGROUND: The use of compliant dual lumen balloon microcatheters (CDLB) for the endovascular treatment of vascular malformations, wide neck aneurysms, and intracranial angioplasty (for vasospasm) is well documented. Navigation of 4 mm or larger CDLB within tortuous and small distal intracranial vessels can be challenging. Recently, the lower profile Scepter Mini balloon microcatheter (SMB) has been approved for use, with potential for improved intracranial navigation. OBJECTIVE: Discuss operative experience of Scepter Mini (Microvention, Aliso Viejo, CA). METHODS: We describe our initial experience with the SMB in a series of nine patients. RESULTS: The balloon microcatheter was used for delivery of liquid embolic in six patients (Case 1, 2, 6-9), adjunct support for delivery or positioning of the Woven Endobridge (WEB) device in two (Case 3,4), and gentle post-deployment repositioning of a WEB device in the last one (Case 5). We were able to successfully navigate the SMB over a 0.008 "micro wire to the target lesion in all the patients. We experienced initial difficulty with injecting liquid embolic in Case 2. We postulate that the SMB was in a tortuous segment of a dural vessel in this patient, and that it kinked on inflation with occlusion of the liquid embolic delivery lumen; this was overcome with slightly proximal repositioning and reinflation of the SMB. CONCLUSION: Our initial experience shows that the SMB has potential to be useful in endovascular neurosurgical procedures requiring balloon assistance within smaller diameter blood vessels.

MR Imaging Safety in the Interventional Environment.

Interventional MR imaging procedures are rapidly growing in number owing to the excellent soft tissue resolution of MR imaging, lack of ionizing radiation, hardware and software advancements, and technical developments in MR imaging-compatible robots, lasers, and ultrasound equipment. The safe operation of an interventional MR imaging system is a complex undertaking, which is only possible with multidisciplinary planning, training, operations and oversight. Safety for both patients and operators is essential for successful operations. Herein, we review the safety concerns, solutions and challenges associated with the operation of a modern interventional MR imaging system.