Reducing frame rate and pulse rate for routine diagnostic cerebral angiography: ALARA principles in practice

OBJECTIVE

Diagnostic cerebral angiograms (DCAs) are widely used in neurosurgery due to their high sensitivity and specificity to diagnose and characterize pathology using ionizing radiation. Eliminating unnecessary radiation is critical to reduce risk to patients, providers, and health care staff. We investigated if reducing pulse and frame rates during routine DCAs would decrease radiation burden without compromising image quality.

METHODS

We performed a retrospective review of prospectively acquired data after implementing a quality improvement protocol in which pulse rate and frame rate were reduced from 15 p/s to 7.5 p/s and 7.5 f/s to 4.0 f/s respectively. Radiation doses and exposures were calculated. Two endovascular neurosurgeons reviewed randomly selected angiograms of both doses and blindly assessed their quality.

RESULTS

A total of 40 consecutive angiograms were retrospectively analyzed, 20 prior to the protocol change and 20 after. After the intervention, radiation dose, radiation per run, total exposure, and exposure per run were all significantly decreased even after adjustment for BMI (all p<0.05). On multivariable analysis, we identified a 46% decrease in total radiation dose and 39% decrease in exposure without compromising image quality or procedure time.

CONCLUSIONS

We demonstrated that for routine DCAs, pulse rate of 7.5 with a frame rate of 4.0 is sufficient to obtain diagnostic information without compromising image quality or elongating procedure time. In the interest of patient, provider, and health care staff safety, we strongly encourage all interventionalists to be cognizant of radiation usage to avoid unnecessary radiation exposure and consequential health risks.

ACR Appropriateness Criteria® Headache: 2022 Update

Headache is an ancient problem plaguing a large proportion of the population. At present, headache disorders rank third among the global causes of disability, accounting for over $78 billion per year in direct and indirect costs in the United States. Given the prevalence of headache and the wide range of possible etiologies, the goal of this document is to help clarify the most appropriate initial imaging guidelines for headache for eight clinical scenarios/variants, which range from acute onset, life-threatening etiologies to chronic benign scenarios. 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 process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Viz.ai Implementation of Stroke Augmented Intelligence and Communications Platform to Improve Indicators and Outcomes for a Comprehensive Stroke Center and Network

BACKGROUND AND PURPOSE

Comprehensive stroke centers continually strive to narrow neurointerventional time metrics. Although process improvements have been put in place to streamline workflows, complex pathways, disparate imaging locations, and fragmented communications all highlight the need for continued improvement.

MATERIALS AND METHODS

This Quality Improvement Initiative (VISIION) was implemented to assess our transition to the Viz.ai platform for immediate image review and centralized communication and their effect on key performance indicators in our comprehensive stroke center. We compared periods before and following deployment. Sequential patients having undergone stroke thrombectomy were included. Both direct arriving large-vessel occlusion and Brain Emergency Management Initiative telemedicine transfer large-vessel occlusion cases were assessed as were subgroups of OnHours and OffHours. Text messaging thread counts were compared between time periods to assess communications. Mann-Whitney U and Student t tests were used.

RESULTS

Eighty-two neurointerventional cases were analyzed pre vs. post time periods: (DALVO-OnHours 7 versus 7, DALVO-OffHours 10 versus 5, BEMI-OnHours 13 versus 6, BEMI-OffHours 17 versus 17). DALVO-OffHours had a 39% door-to-groin reduction (157 versus 95 minutes, P = .009). DALVO-All showed a 32% reduction (127 versus 86 minutes, P = .006). BEMI-All improved 33% (42 versus 28 minutes, P = .036). Text messaging thread counts improved 30% (39 versus 27, P = .04).

CONCLUSIONS

There was an immediate improvement following Viz.ai implementation for both direct arriving and telemedicine transfer thrombectomy cases. In the greatest opportunity subset (direct arriving large-vessel occlusion-OffHours: direct arriving cases requiring team mobilization off-hours), we noted a 39% improvement. With Viz.ai, we noted that immediate access to images and streamlined communications improved door-to-groin time metrics for thrombectomy. These results have implications for future care processes and can be a model for centers striving to optimize workflow and improve thrombectomy timeliness.

Abstract WP84: (VISIION): Viz.ai Implementation Of Stroke Augmented Intelligence And Communications Platform To Improve Indicators And Outcomes For A Comprehensive Stroke Center And Network

Background: Comprehensive Stroke Centers (CSCs) strive to narrow rt-PA and “Door To Groin” (DTG) neurointerventional (NIR) times. Process improvement workflows have been put in place for rt-PA. While similar processes have been implemented to streamline workflows for hyperacute NIR cases, complex pathways, disparate imaging locations, and fragmented communications all highlight a need for continued improvements.

Methods: This quality improvement initiative (IRB #210525) was implemented to assess our transition to the Viz.ai platform for immediate image review and centralized communication and its effect on key performance indicators (KPIs) in an already robust CSC. We compared 6 month periods prior to and following deployment. Sequential stroke NIR patients were included. Both Direct Arriving LVO (DALVO) and telemedicine transfer LVO (BEMI) cases were assessed. We assessed subgroups of DALVO-OnHours, DALVO-OffHours, BEMI-OnHours, and BEMI-OffHours. Mann-Whitney U was utilized.

Results: Eighty-two NIR cases were analyzed pre v. post Viz.ai implementation (DALVO-OnHours 7 v. 7, DALVO-OffHours 10 v. 5, BEMI-OnHours 13 v. 6, BEMI-OffHours 17 v. 17). DALVO-OnHours improved 19% (97min, 79min; p=0.201) in median DTG times. DALVO-OffHours had a significant 39% reduction (157min, 95min; p=0.009). DALVO-“All” showed a significant 32% reduction (127min, 86 min; p=0.006). BEMI-OnHours improved 18% (37min, 31min; p=0.337). BEMI-OffHours improved 38% (45min, 28min; p=0.077). BEMI-“All” significantly improved 33% (42min, 28min; p=0.036). Overall, there was a 22% reduction (50min, 39min; p=0.066) after Viz.ai implementation.

Conclusions: There was an immediate KPI improvement following Viz.ai implementation for both direct arrival and telemedicine transfer NIR cases (32% and 33% respectively). In the greatest opportunity subset (direct arriving cases requiring team mobilization off hours without benefit of telemedicine transfer lead time) we noted a 39% improvement. With Viz.ai, we noted immediate access to images and streamlined group communications, even in an already well-functioning CSC. These results have implications for future care processes and can be a model for centers striving to optimize workflow and improve NIR timeliness.

ACR Appropriateness Criteria® Cerebrovascular Diseases-Aneurysm, Vascular Malformation, and Subarachnoid Hemorrhage

Cerebrovascular disease is a broad topic. This document focuses on the imaging recommendations for the varied clinical scenarios involving intracranial aneurysms, vascular malformations, and vasculitis, which all carry high risk of morbidity and mortality. Additional imaging recommendations regarding complications of these conditions, including subarachnoid hemorrhage and vasospasm, are also covered. While each variant presentation has unique imaging recommendations, the major focus of this document is neurovascular imaging techniques. 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.

ACR Appropriateness Criteria® Syncope

Syncope and presyncope lead to well over one million emergency room visits in the United States each year. Elucidating the cause of syncope or presyncope, which are grouped together given similar etiologies and outcomes, can be exceedingly difficult given the diverse etiologies. This becomes more challenging as some causes, such as vasovagal syncope, are relatively innocuous while others, such as cardiac-related syncope, carry a significant increased risk of death. While the mainstay of syncope and presyncope assessment is a detailed history and physical examination, imaging can play a role in certain situations. In patients where a cardiovascular etiology is suspected based on the appropriate history, physical examination, and ECG findings, resting transthoracic echocardiography is usually considered appropriate for the initial imaging. While no imaging studies are considered usually appropriate when there is a low probability of cardiac or neurologic pathology, chest radiography may be appropriate in certain clinical situations. 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.

ACR Appropriateness Criteria® Headache

Headache is one of the most common human afflictions. In most cases, headaches are benign and idiopathic, and resolve spontaneously or with minor therapeutic measures. Imaging is not required for many types of headaches. However, patients presenting with headaches in the setting of "red flags" such as head trauma, cancer, immunocompromised state, pregnancy, patients 50 years or older, related to activity or position, or with a corresponding neurological deficit, may benefit from CT, MRI, or noninvasive vascular imaging to identify a treatable cause. This publication addresses the initial imaging strategies for headaches associated with the following features: severe and sudden onset, optic disc edema, "red flags," migraine or tension-type, trigeminal autonomic origin, and chronic headaches with and without new or progressive features. 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.

ACR Appropriateness Criteria® Seizures and Epilepsy

Seizures and epilepsy are a set of conditions that can be challenging to diagnose, treat, and manage. This document summarizes recommendations for imaging in different clinical scenarios for a patient presenting with seizures and epilepsy. MRI of the brain is usually appropriate for each clinical scenario described with the exception of known seizures and unchanged semiology (Variant 3). In this scenario, it is unclear if any imaging would provide a benefit to patients. In the emergent situation, a noncontrast CT of the head is also usually appropriate as it can diagnose or exclude emergent findings quickly and is an alternative to MRI of the brain in these clinical scenarios. 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.

ACR Appropriateness Criteria® Movement Disorders and Neurodegenerative Diseases

Movement disorders and neurodegenerative diseases are a variety of conditions that involve progressive neuronal degeneration, injury, or death. Establishing the correct diagnosis of a movement disorder or neurodegenerative process can be difficult due to the variable features of these conditions, unusual clinical presentations, and overlapping symptoms and characteristics. MRI has an important role in the initial assessment of these patients, although a combination of imaging and laboratory and genetic tests is often needed for complete evaluation and management. This document summarizes the imaging appropriateness data for rapidly progressive dementia, chorea, Parkinsonian syndromes, suspected neurodegeneration with brain iron accumulation, and suspected motor neuron 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.

ACR Appropriateness Criteria® Dementia

Degenerative disease of the central nervous system is a growing public health concern. The primary role of neuroimaging in the workup of patients with probable or possible Alzheimer disease has typically been to exclude other significant intracranial abnormalities. In general, the imaging findings in structural studies, such as MRI, are nonspecific and have limited potential in differentiating different types of dementia. Advanced imaging methods are not routinely used in community or general practices for the diagnosis or differentiation of forms of dementia. Nonetheless, in patients who have been evaluated by a dementia expert, FDG-PET helps to distinguish Alzheimer disease from frontotemporal dementia. In patients with suspected dementia with Lewy bodies, functional imaging of the dopamine transporter (ioflupane) using SPECT may be helpful. In patients with suspected normal-pressure hydrocephalus, DTPA cisternography and HMPAO SPECT/CT brain may provide assessment. 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.

The effect of hospital safety-net burden on outcomes, cost, and reportable quality metrics after emergent clipping and coiling of ruptured cerebral aneurysms

OBJECTIVE

Safety-net hospitals deliver care to a substantial share of vulnerable patient populations and are disproportionately impacted by hospital payment reform policies. Complex elective procedures performed at safety-net facilities are associated with worse outcomes and higher costs. The effects of hospital safety-net burden on highly specialized, emergent, and resource-intensive conditions are poorly understood. The authors examined the effects of hospital safety-net burden on outcomes and costs after emergent neurosurgical intervention for ruptured cerebral aneurysms.

METHODS

The authors conducted a retrospective analysis of the Nationwide Inpatient Sample (NIS) from 2002 to 2011. Patients ≥ 18 years old who underwent emergent surgical clipping and endovascular coiling for aneurysmal subarachnoid hemorrhage (SAH) were included. Safety-net burden was defined as the proportion of Medicaid and uninsured patients treated at each hospital included in the NIS database. Hospitals that performed clipping and coiling were stratified as low-burden (LBH), medium-burden (MBH), and high-burden (HBH) hospitals.

RESULTS

A total of 34,647 patients with ruptured cerebral aneurysms underwent clipping and 23,687 underwent coiling. Compared to LBHs, HBHs were more likely to treat black, Hispanic, Medicaid, and uninsured patients (p < 0.001). HBHs were also more likely to be associated with teaching hospitals (p < 0.001). No significant differences were observed among the burden groups in the severity of subarachnoid hemorrhage. After adjusting for patient demographics and hospital characteristics, treatment at an HBH did not predict in-hospital mortality, poor outcome, length of stay, costs, or likelihood of a hospital-acquired condition.

CONCLUSIONS

Despite their financial burden, safety-net hospitals provide equitable care after surgical clipping and endovascular coiling for ruptured cerebral aneurysms and do not incur higher hospital costs. Safety-net hospitals may have the capacity to provide equitable surgical care for highly specialized emergent neurosurgical conditions.

Initial Experience Using a High-Definition 3-Dimensional Exoscope System for Microneurosurgery

BACKGROUND

The operative microscope and endoscope have significantly advanced modern neurosurgery. These devices are nonetheless limited by high costs and suboptimal optics, ergonomics, and maneuverability. A recently developed extracorporeal telescope ("exoscope") operative system combines characteristics from both the operative microscope and endoscope and provides an affordable, portable, high-definition operative experience. Widespread use of exoscopes in neurosurgery has previously been limited by a lack of stereopsis with 2-dimensional(2-D) monitors.

OBJECTIVE

To assess the surgical potential of a novel, 3-D, high-definition (4K-HD) exoscope system.

METHODS

Assess dissection time and visualization of critical structures in a series of human cadaveric cranial neurosurgical approaches with the 3-D 4K-HD exoscope as compared to a standard operating microscope.

RESULTS

Dissection times and visualization of critical structures was comparable with the 3-D 4K-HD exoscope and a standard operating microscope. The low-profile exoscope nonetheless allowed for larger operative corridors, enhanced instrument maneuverability, and less obstruction in passing instrumentation. The large monitor also resulted in an immersive surgical experience, and gave multiple team members the same high-quality view as the primary operator. Finally, the exoscope possessed a more ergonomically favorable setup as compared to the traditional microscope, allowing the surgeon to be in a neutral position despite the operative angle.

CONCLUSION

The novel 3-D 4K-HD exoscope system possesses favorable optics, ergonomics, and maneuverability as compared to the traditional operating microscope, with the exoscope's shared surgical view possessing obvious educational and workflow advantages. Further clinical trials are justified to validate this initial cadaveric experience.

Abstract P270: Carotid Stenosis: A Frequently Overlooked Etiology of Secondary Hypertension

Introduction: Hypertension is one of the most prevalent etiologies for stroke, myocardial infarction, heart failure, retinopathy, and renal failure. Both primary and secondary hypertension can frequently be controlled and end organ damage be prevented by medications alone. However, atherosclerotic diseases resulting in end organ ischemic demand can overwhelm even the most aggressive treatment strategies, which have been demonstrated in cases of renal artery stenosis. However, carotid stenosis is an often-overlooked etiology in secondary hypertension, which can be treated by open surgery or endovascular stenting.

Methods: In this retrospective study, the medical records of 43 consecutive patients who underwent carotid stenting for symptomatic or severe internal carotid artery stenosis from November of 2013 to December of 2015 were reviewed. All patients either had a prior stroke, TIA, or stenosis of the internal carotid artery measuring greater than 70% by NASCET criteria. All of the patients in the study had a diagnosis of hypertension. The systolic and diastolic blood pressures as well as the anti-hypertensive medication regimen of all of the patients involved were recorded before the surgery, immediately following surgery, and 3 months after the surgery. The average blood pressure reduction was calculated immediately following surgery and at 3 months.

Results: The average reduction in systolic blood pressures immediately following surgery and at 3 months were 13.86 mmHg and 5.89 mmHg, respectively. The average reduction in diastolic blood pressures immediately following surgery and at 3 months were 8.96 mmHg and 1.84 mmHg, respectively. Additionally, the number of anti-hypertensive medications and the dosages decreased in 11 patients, including two of which who no longer required anti-hypertensives after stenting.

Conclusion: Although the treatment of carotid artery disease is typically reserved for patients with cerebrovascular compromise, carotid artery stenting and endarterectomy can be useful adjunctives in the treatment of malignant and uncontrolled hypertension.

Minimally invasive treatment of intracerebral hemorrhage

Intracerebral hemorrhages (ICH) cause high levels of morbidity and mortality. Secondary neuronal injury from perihematomal edema is thought to contribute to poor outcomes. Surgical evacuation of ICH is a theoretically promising approach, yet clinical data on the efficacy of standard craniotomy approaches is limited. Recent exploration of minimally invasive techniques for ICH removal includes stereotactic surgery combined with intra-clot thrombolysis, as well as endoscopic hematoma evacuation. Ongoing trials have demonstrated the safety of such minimally invasive approaches, and pending efficacy data from these studies is likely to change the standard management of ICH.

Hemorrhagic intramedullary solitary fibrous tumor of the conus medullaris: case report

The differential diagnosis of spinal tumors is guided by anatomical location and imaging characteristics. Diagnosis of rare tumors is made challenging by abnormal features. The authors present the case of a 47-year-old woman who presented with progressive subacute right lower-extremity weakness and numbness of the right thigh. Physical examination further revealed an extensor response to plantar reflex on the right and hyporeflexia of the right Achilles and patellar reflexes. Magnetic resonance imaging of the lumbar spine demonstrated an 8-mm intramedullary exophytic nodule protruding into a hematoma within the conus medullaris. Spinal angiography was performed to rule out an arteriovenous malformation, and resection with hematoma evacuation was completed. Pathological examination of the resected mass demonstrated a spindle cell neoplasm with dense bundles of collagen. Special immunostaining was performed and a diagnosis of solitary fibrous tumor (SFT) was made. SFTs are mesenchymally derived pleural neoplasms, which rarely present at other locations of the body, but have been increasingly described to occur as primary neoplasms of the spine and CNS. The authors believe that this case is unique in its rare location at the level of the conus, and also that this is the first report of a hemorrhagic SFT in the spine. Therefore, with this report the authors add to the literature the fact that this variant of an increasingly understood but heterogeneous tumor can occur, and therefore should be considered in the differential of clinically similar tumors.