Arterial spin labeling as an ancillary assessment to postoperative conventional angiogram in pediatric moyamoya disease.

OBJECTIVE: Digital subtraction angiography (DSA) is commonly performed after pial synangiosis surgery for pediatric moyamoya disease to assess the degree of neovascularization. However, angiography is invasive, and the risk of ionizing radiation is a concern in children. In this study, the authors aimed to identify whether arterial spin labeling (ASL) can predict postoperative angiogram grading. In addition, they sought to determine whether patients who underwent ASL imaging without DSA had similar postoperative outcomes when compared with patients who received ASL imaging and postoperative DSA. METHODS: The medical records of pediatric patients who underwent pial synangiosis for moyamoya disease at a quaternary children's hospital were reviewed during a 10-year period. ASL-only and ASL+DSA cohorts were analyzed. The frequency of preoperative and postoperative symptoms was analyzed within each cohort. Three neuroradiologists assigned a visual ASL grade for each patient indicating the change from the preoperative to postoperative ASL perfusion sequences. A postoperative neovascularization grade was also assigned for patients who underwent DSA. RESULTS: Overall, 21 hemispheres of 14 patients with ASL only and 14 hemispheres of 8 patients with ASL+DSA were analyzed. The groups had similar rates of MRI evidence of acute or chronic stroke preoperatively (61.9% in the ASL-only group and 64.3% in the ASL+DSA group). In the entire cohort, transient ischemic attack (TIA) (p = 0.027), TIA composite (TIA or unexplained neurological symptoms; p = 0.0006), chronic headaches (p = 0.035), aphasia (p = 0.019), and weakness (p = 0.001) all had decreased frequency after intervention. The authors found a positive association between revascularization observed on DSA and the visual ASL grading (p = 0.048). The visual ASL grades in patients with an angiogram indicating robust neovascularization demonstrated improved perfusion when compared with the ASL grades of patients with a poor neovascularization. CONCLUSIONS: Noninvasive ASL perfusion imaging had an association with postoperative DSA neoangiogenesis following pial synangiosis surgery in children. There were no significant postoperative stroke differences between the ASL-only and ASL+DSA cohorts. Both cohorts demonstrated significant improvement in preoperative symptoms after surgery. Further study in larger cohorts is necessary to determine whether the results of this study are validated in order to circumvent the invasive catheter angiogram.

Vascular imaging of the spine in the US Medicare population: Catheter and MR angiography volumes from 2004 to 2016.

AIMS: The purpose of our study was to analyze utilization trends and physician specialty distribution in spinal catheter angiography and magnetic resonance angiography in the Medicare fee-for-service population. METHODS: Data from the CMS Physician/Supplier Procedure Summary Master Files for 2004 to 2016 were used for this study. The Current Procedural Terminology version 4 codes for spinal magnetic resonance angiography (72159) and spinal catheter angiography (75705) were used to analyze the volumes of these procedures. Using Medicare's 108 specialty code, we compared procedure volumes among physician specialties. Data analysis was performed using SAS version 9.3 for Windows. RESULTS: The volume of spinal catheter angiography performed was 4758 in 2004, peaked at 6869 in 2012, and dropped to 6656 in 2016. Overall, the volume of spinal catheter angiography increased by 40% from 2004 to 2016. Radiologists performed the majority of these procedures (3736 or 56.1%) in 2016, followed by neurosurgeons (2456 or 36.9%), and neurologists (346 or 5.2%). The spinal magnetic resonance angiography volume fluctuated between 0 and 1 from 2004 to 2009, then precipitously increased to 40 in 2010, peaked at 133 in 2011, and declined to 81 in 2016. The volume of spinal magnetic resonance angiography procedures increased by 8000% from 2004 to 2016, with radiologists performing the majority of them. CONCLUSION: Our results show that spinal catheter angiography volumes continue to rise in the Medicare fee-for-service population, and are largely performed by radiologists, neurosurgeons, and neurologists. Although spinal magnetic resonance angiography volumes have started to increase, they comprise only a small fraction of studies performed for vascular evaluation of the spine.

Neurointerventional Radiology for the Aspiring Radiology Resident: Current State of the Field and Future Directions.

OBJECTIVE: The purposes of this study were to document recent trends in stroke intervention at a tertiary-care facility with a comprehensive stroke center and to analyze current procedure volumes and the employment of specialty providers in neurointerventional radiology (NIR). MATERIALS AND METHODS: Institutional trends in the volume of mechanical thrombectomy were analyzed on the basis of the number of patients who underwent mechanical thrombectomy from 2013 to 2017. To evaluate the current status of mechanical thrombectomy volumes in the United States, the number of patients in the Medicare fee-for-service database who underwent mechanical thrombectomy in 2016 was assessed. The specialty backgrounds of the various providers who performed mechanical thrombectomy were analyzed. Procedure volumes for intracranial stenting, embolization, and vertebral augmentation procedures were assessed. RESULTS: From 2013 to 2017, the total numbers of mechanical thrombectomy procedures for acute ischemic stroke were 19 in 2013 and 111 in 2017. The total volume of mechanical thrombectomy procedures in the Medicare fee-for-service population in 2016 was 7479. For intracranial endovascular procedures, 20,850 were performed in the U.S. Medicare population in 2015 and 22,511 in 2016. Radiologists performed 45% of procedures in 2016; neurosurgeons, 41%; and neurologists, 11%. When the total numbers of percutaneous brain and spine procedures were combined, radiologists performed 41%; neurosurgeons, 23%; and neurologists, 3%. In 2016, there were a total of 220 active NIR staff at the NIR programs with rotating residents or fellows. In these programs, 49% of staff members were neuroradiologists, 41% were neurosurgeons, and 10% were neurologists. Of the 72 NIR departments with confirmed rotating fellows or residents, 14 had only neuroradiologists on staff, six had only neurosurgeons, and one had only neurologists. CONCLUSION: Increasing radiology resident interest and participation in NIR should ensure a steady influx of radiologists into the field, continuing the strong tradition of radiology participation, leadership, and innovation in NIR.