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.

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.

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.

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.

Thrombectomy in DAWN- and DEFUSE-3-Ineligible Patients: A Subgroup Analysis From the BEST Prospective Cohort Study.

BACKGROUND: Because of the overwhelming benefit of thrombectomy for highly selected trial patients with large vessel occlusion (LVO), some trial-ineligible patients are being treated in practice. OBJECTIVE: To determine the safety and efficacy of thrombectomy in DAWN/DEFUSE-3-ineligible patients. METHODS: Using a multicenter prospective observational study of consecutive patients with anterior circulation LVO who underwent late thrombectomy, we compared symptomatic intracerebral hemorrhage (sICH) and good outcome (90-d mRS 0-2) among DAWN/DEFUSE-3-ineligible patients to trial-eligible patients and to untreated DAWN/DEFUSE-3 controls. RESULTS: Ninety-eight patients had perfusion imaging and underwent thrombectomy >6 h; 46 (47%) were trial ineligible (41% M2 occlusions, 39% mild deficits, 28% ASPECTS <6). In multivariable regression, the odds of a good outcome (aOR 0.76, 95% CI 0.49-1.19) and sICH (aOR 3.33, 95% CI 0.42-26.12) were not different among trial-ineligible vs eligible patients. Patients with mild deficits were more likely to achieve a good outcome (aOR 3.62, 95% CI 1.48-8.86) and less sICH (0% vs 10%, P = .16), whereas patients with ASPECTS <6 had poorer outcomes (aOR 0.14, 95% CI 0.05-0.44) and more sICH (aOR 24, 95% CI 5.7-103). Compared to untreated DAWN/DEFUSE-3 controls, trial-ineligible patients had more sICH (13%BEST vs 3%DAWN [P = .02] vs 4%DEFUSE [P = .05]), but were more likely to achieve a good outcome at 90 d (36%BEST vs 13%DAWN [P < .01] vs 17%DEFUSE [P = .01]). CONCLUSION: Thrombectomy is used in practice for some patients ineligible for the DAWN/DEFUSE-3 trials with potentially favorable outcomes. Additional trials are needed to confirm the safety and efficacy of thrombectomy in broader populations, such as large core infarction and M2 occlusions.

Stent-Assisted Woven EndoBridge Implantation for Treatment of Wide-Necked Aneurysm Residual: Angiographic Video.

Woven EndoBridge (WEB) is an intrasaccular flow-disrupting device that has recently been approved by the U.S. Food and Drug Administration (FDA) for treatment of wide-neck ruptured and unruptured aneurysms at arterial bifurcations. Successful and effective treatment of aneurysms with the WEB device requires accurate sizing. For optimal positioning of the WEB device within the aneurysm sac, the diameter of the device has to exceed by the mean diameter of the aneurysm by 1.0 mm. However, this predictably results in an increase in the height of the device. In shallow, wide-necked aneurysms, this increase in height of the WEB device could result in encroachment of the device on the parent artery or branch vessel origins. In these circumstances, the placement of an intracranial stent can prevent such encroachment. In this video, we demonstrate the operative technique of stent-assisted WEB device placement that was performed at our institution for the treatment of a recurrent basilar apex aneurysm (Video 1). This previously ruptured aneurysm had been treated initially with primary coil embolization, and the patient consented to endovascular treatment of her aneurysm recurrence. The video illustrates this procedure using a combination of fluoroscopic images, fluoroscopic cines, and digital subtraction angiograms.

Development of a Novel Canine Model of Ischemic Stroke: Skull Base Approach with Transient Middle Cerebral Artery Occlusion.

OBJECTIVE: Although canine stroke models have several intrinsic advantages, establishing consistent and reproducible territorial stroke in these models has been challenging because of the abundance of collateral circulation. We have described a skull-base surgical approach that yields reproducible stroke volumes. METHODS: Ten male beagles were studied. In all 10 dogs, a craniectomy was performed to expose the circle of Willis. Cerebral aneurysm clips were temporarily applied to the middle cerebral artery (MCA), anterior cerebral artery (ACA), posterior cerebral artery, and/or ophthalmic artery (OA) for 1 hour, followed by cauterization of the distal MCA pial collateral vessels. Indocyanine green angiography was performed to assess the local blood flow to the intended area of infarction. The dogs' neurologic examination was evaluated, and the stroke burden was quantified using magnetic resonance imaging. RESULTS: High mortality was observed after 1-hour clip occlusion of the posterior cerebral artery, MCA, ACA, and OA (n = 4). Without coagulation of the MCA collateral vessels, 1-hour occlusion of the MCA and/or ACA and OA yielded inconsistent stroke volumes (n = 2). In contrast, after coagulation of the distal MCA pial collateral vessels, 1-hour occlusion of the MCA, ACA, and OA yielded consistent territorial stroke volumes (n = 4; average stroke volume, 9.13 ± 0.90 cm3; no surgical mortalities), with reproducible neurologic deficits. CONCLUSION: Consistent stroke volumes can be achieved in male beagles using a skull base surgical approach with temporary occlusion of the MCA, ACA, and OA when combined with cauterization of the distal MCA pial collateral vessels.

Gadolinium to the rescue for mechanical thrombectomy in acute ischemic stroke.

INTRODUCTION: Mechanical thrombectomy in the setting of acute ischemic stroke (AIS) requires cerebral digital subtraction angiography (DSA), typically performed with iodinated contrast medium. We present a case of emergent cerebral DSA and mechanical thrombectomy using gadolinium-based contrast for cerebral DSA in a patient with a history of anaphylaxis to iodinated contrast agents (ICs). CASE REPORT: A 72-year-old man developed left ventricle assist device thrombus while on anticoagulation. During hospitalization he suffered right middle cerebral artery occlusion with a National Institutes of Health stroke scale score of 10. He had a history of anaphylaxis and the advanced directives revealed do not resuscitate/do not intubate status. We performed an emergent DSA as part of thrombectomy procedure using gadolinium-based contrast mixed in 1:1 proportion with normal saline. The images obtained were of adequate quality and the patient underwent successful thrombectomy with modified thrombolysis in cerebral infarction 2B recanalization. CONCLUSION: Gadolinium-based contrast agents could be effective alternatives for cerebral DSA in patients undergoing mechanical thrombectomy for AIS who have a history of anaphylactic reaction to ICs.

Safety and Feasibility of Balloon-Assisted Embolization with Onyx of Brain Arteriovenous Malformations Revisited: Personal Experience with the Scepter XC Balloon Microcatheter.

BACKGROUND/OBJECTIVE: Compliant dual-lumen balloon microcatheters have been used to perform balloon-assisted embolization (BAE) of brain arteriovenous malformations (AVMs) with ethylene vinyl alcohol copolymer (Onyx). However, vessel rupture and microcatheter retention have been reported from BAE using these microcatheters. Using an extra-compliant balloon microcatheter (Scepter XC; Microvention, Tustin, CA, USA) could help avoid pial vessel rupture during BAE. We herein report our experience using this balloon microcatheter for BAE. METHODS: This retrospective study included patients who underwent BAE of brain AVMs at our institution between June 2012 and March 2017. RESULTS: The extra-compliant Scepter XC balloon microcatheter was used for BAE of brain AVMs in 23 patients aged 44.3 ± 16.7 years (range 0-65 years). A total of 40 intracranial vessels (39 pial arteries and 1 pial vein) were catheterized and embolized during 30 separate sessions. In all instances, the balloon microcatheter could be successfully advanced to the AVM nidus. A mean volume of 2.4 ± 1.7 mL (range 0.65-4.6 mL) of Onyx was injected per session. There were no instances of vessel rupture, microcatheter retention, or stroke. CONCLUSION: Utilization of the extra-compliant balloon microcatheter results in safe and effective BAE, which adds to the growing experience with BAE for AVM treatment.

Embolization of a complex coronary to pulmonary artery fistula using balloon assisted liquid embolic injection: A novel technique.

Complex Coronary artery to Pulmonary artery fistulas (CPFs) can be difficult to manage with embolization or ligation. An 88-year-old woman with exertional angina was found to have a complex precordial CPF, severe Mitral regurgitation, and Pulmonary Hypertension. CPF treatment was recommended prior to minimally invasive mitral valve replacement (to avoid postoperative myocardial ischemia from worsened steal). The CPF was supplied by multiple branches from the LAD and RCA, and formed a complex common varicosity with multiple drainage channels to the pulmonary artery. The CPF was treated by injecting a liquid embolic agent, Ethylene Vinyl Alcohol Copolymer (Onyx, Medtronic, MN), into two of the feeding arteries arising from the RCA through a Scepter C Dual lumen balloon micro catheter (Microvention, Aliso Viejo, CA. This resulted in complete obliteration of the fistula, and the patient subsequently underwent successful mitral valve replacement surgery.

Safety of cerebral angiography and neuroendovascular therapy in patients with chronic kidney disease.

PURPOSE: Contrast-induced nephropathy is a common clinical concern in patients undergoing neuroendovascular procedures, especially in those with pre-existent kidney disease. We aimed to define the incidence of contrast-induced nephropathy in these high-risk patients in our practice. METHODS: We analyzed data retrospectively from patients undergoing neuroendovascular procedures at two academic medical centers over a 4-year period. Contrast-induced nephropathy was determined by an absolute increase in serum creatinine of 0.5 mg/dL or a rise from its baseline value by ≥ 25%, at 48-72 h after exposure to contrast agent after excluding other causes of renal impairment. High-risk patients were identified as those with pre-procedural estimated glomerular filtration rate < 60 mL/min irrespective of creatinine level, corresponding to stages 3-5 of chronic kidney disease. RESULTS: One hundred eighty-five high-risk patients undergoing conventional cerebral angiography and neuroendovascular interventions were identified. Only 1 out of 184 (0.54%) high-risk patients developed contrast-induced nephropathy. That one patient had stage 5 chronic kidney disease and multiple other risk factors. CONCLUSION: We have observed a very low rate of renal injury in patients with chronic kidney disease, traditionally considered high risk for neuroendovascular procedures. Multiple factors may be responsible in the risk reduction of contrast-induced nephropathy in this patient population.

ACR Appropriateness Criteria® Cranial Neuropathy.

Evaluation of cranial neuropathy can be complex given the different pathway of each cranial nerve as well as the associated anatomic landmarks. Radiological evaluation requires imaging of the entire course of the nerve from its nucleus to the end organ. MRI is the modality of choice with CT playing a complementary role, particularly in the evaluation of the bone anatomy. Since neoplastic and inflammatory lesions are prevalent on the differential diagnosis, contrast enhanced studies are preferred when possible. The American College of Radiology Appropriateness Criteria are evidencebased guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Salvage of Herniated Flow Diverters Using Stent and Balloon Anchoring Techniques: A Technical Note.

BACKGROUND: The pipeline embolization device (PED; Medtronic, MN, USA) can sometimes herniate into the aneurysmal sac in an unexpected manner during or shortly after its deployment due to device foreshortening. In this report, we describe 2 endovascular techniques, which can be used to reposition a herniated PED construct into a more favorable alignment. SUMMARY: In a 67-year-old patient who had an intraprocedural herniation of a PED device into a giant cavernous aneurysm, a stent anchor technique was used to reverse the herniation, reorient the PED construct, and achieve successful flow diversion. In a different patient with a giant superior hypophyseal aneurysm, a balloon anchor technique followed by deployment of an LVIS Jr (Microvention, Tustin, CA, USA) stent was used to reverse the herniation into the aneurysmal sac. KEY MESSAGES: Stent anchor and balloon anchor techniques as described here can be used to reposition PED constructs, which have unexpectedly herniated into the aneurysm sac during attempted flow diversion for the treatment of giant aneurysms.

ACR Appropriateness Criteria® Cerebrovascular Disease.

Diseases of the cerebral vasculature represent a heterogeneous group of ischemic and hemorrhagic etiologies, which often manifest clinically as an acute neurologic deficit also known as stroke or less commonly with symptoms such as headache or seizures. Stroke is the fourth leading cause of death and is a leading cause of serious long-term disability in the United States. Eighty-seven percent of strokes are ischemic, 10% are due to intracerebral hemorrhage, and 3% are secondary to subarachnoid hemorrhage. The past two decades have seen significant developments in the screening, diagnosis, and treatment of ischemic and hemorrhagic causes of stroke with advancements in CT and MRI technology and novel treatment devices and techniques. Multiple different imaging modalities can be used in the evaluation of cerebrovascular disease. The different imaging modalities all have their own niches and their own advantages and disadvantages in the evaluation of cerebrovascular disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

All that bleeds is not black: susceptibility weighted imaging of intracranial hemorrhage and the effect of T1 signal.

PURPOSE: To determine if intracranial hemorrhages (ICH) are always hypointense on Susceptibility weighted imaging (SWI) and to determine the effect of T1-signal intensity on the appearance of ICH in SWI series. METHODS: SWI and T1-signal intensities of ICH were retrospectively studied in a series of patients. SWI signal intensities were statistically correlated with T1-signal intensities. RESULTS: In a series of 57 MRI scans from 40 patients, ICH was hypointense in 19, mixed-intensity in 21, and hyperintense in 17. Hyperintensity of ICH on SWI was significantly associated with increased T1 signal (P<.001). CONCLUSION: ICH can have a varied appearance on SWI.