Despite an increasing number of medical students and residents pursuing careers in interventional radiology, there remains confusion regarding the training pathways for those who want to further specialize in interventional neuroradiology. Interventional neuroradiology (INR), or endovascular surgical neuroradiology, focuses on treating diseases of the brain, neck and spine using minimally-invasive, image-guided techniques. In addition to treating neurological conditions such as strokes, cerebral aneurysms, and cerebral arteriovenous malformations, INR practitioners are also trained to perform and interpret diagnostic cerebral angiography.
To practice in INR, there are currently three established pathways:
- Neurosurgery residency (6-8 years) followed by INR fellowship (1-2 years), for a total of 7-10 years
- Diagnostic radiology residency (5 years), followed by neuroradiology fellowship (1 year), followed by INR fellowship (1-2 years) for a total of 7-8 years
- Neurology residency (4 years), followed by stroke or neurocritical care fellowship (1-2 years), followed INR fellowship (1-2 years) for a total of 7-8 years
During the 1-2 year fellowship, INR trainees learn how to diagnose and manage neurovascular disease, ultimately achieving expertise in neuroangiographic procedures. After completing any of the three aforementioned training pathways, interventionalists are able to manage neurovascular patients in the inpatient and outpatient settings. Several consensus papers analyzed the minimum training standards required for interventional neuroradiologists to competently manage stroke patients. One such paper outlines the INR Graduate Medical Education (GME) training requirements, which are stated below:
- A residency should include documented training in diagnosis and management of acute stroke, interpretation of cerebral arteriography, and neuroimaging under a board certified neurosurgeon/neurologist/neuroradiologist
- Neurointerventional training should be under the direction of a neurointerventionalist at a high volume center with preferred minimum one year of dedicated INR training in an accredited program
These requirements are vague and can be broadly interpreted. Myers et al delineate a more specific set of procedural competencies recommended for trainees:
- 100 cerebral angiograms
- Documented training with microcatheters and micro-guidewires under a neurointerventionalist
- Documented experience assessing the performance of endovascular stroke procedures as the primary operator in 10 patients under supervision of fellowship trained/credentialed neurointerventionalist
Finally, on a basis of professional membership, neurointerventionalists must document direct involvement in a minimum of 100 neurointerventional procedures during training to qualify for senior membership in the Society for Neurointerventional Surgery. Based on current training paradigms, no established pathway exists for interventional radiologists to directly access INR fellowship training following either IR fellowship or IR/DR integrated residency. Interventional radiologists would thus have to complete an additional neuroradiology fellowship before pursuing INR fellowship, stretching the total training time to 8-9 years.
To some, this potential extra year in training may seem insignificant. However, other interventionalists believe that a more streamlined pathway toward INR fellowship should exist, such as through increased exposure to neuroradiology and neurological critical care during the diagnostic portion of IR training for those interested in INR. Currently, whether IRs can directly access INR fellowship is considered on a case-by-case and institution-by-institution basis. Some neurointerventional fellowship directors welcome IRs with proven experience in neurological care and intervention, but others instead prefer applicants with formal training in neuroradiology and neurocritical care.
Written by Yuli Zhu, MD, PGY1, Integrated IR resident at NYU
 Lavine, S. D., et al. “Training guidelines for endovascular ischemic stroke intervention: an international multi-society consensus document.” American Journal of Neuroradiology 37.4 (2016): E31-E34.
 Meyers, Philip M., et al. “Performance and training standards for endovascular ischemic stroke treatment.” Journal of neurointerventional surgery 1.1 (2009): 10-12.