John Cerne, BS

Imagine a motorcycle rider crashes his bike on his way to work. He hits his head on the road. He is taken to the hospital, but the CT scanner is broken. The patient feels fine and leaves the hospital. Later he becomes obtunded and passes away. If access to a CT scanner was available, the epidural bleed would have been seen. And, his life would have been saved.

The World Health Organization (WHO) estimates that two-thirds of the world’s population, such as this patient, lacks access to basic radiology care. Interventional radiology is even more inaccessible, and the influence this field can have on patient care is just as remarkable. Interventional radiology is challenging to implement in resource-limited settings because of difficulty maintaining and acquiring radiographic equipment, as well as a dearth of trained practitioners. Fortunately, these are not insurmountable challenges. Through adaptation and education, interventional radiologists can bring their services to populations throughout the world.

The first challenge is physical capital. Interventional radiology relies on equipment that is expensive to purchase and expensive to maintain. A CT scanner can cost up to $2.5 million, and an MRI scanner can cost up to $3 million. The average cost of an angiography system is $1.5 million. The WHO estimates that donations account for 80 percent of the medical equipment in developing countries.

When equipment is acquired through a donation, it is often misallocated in resource-limited settings

. A clinic in rural Africa may receive a CT scanner. However, if the CT scanner malfunctions, there may be no nearby technician to fix the machine. The CT scanner will quickly become dormant. A reliable power grid and climate-controlled settings are also uncommon, yet essential, for interventional radiology equipment. Fluoroscopy, CT, angiography, MRI, nuclear medicine, and advanced ultrasound equipment are often found in “medical equipment graveyards.” While 1 percent of medical equipment is out-of-service in high-income countries, 40 percent of medical equipment is out-of-service in low and middle-income countries

Human capital is another challenge that faces the practice of interventional radiology in resource-limited settings. For example, there were fewer than five practicing interventional radiologists in Nigeria in 2019. With a population of 200 million people, supply cannot meet demand

. The training paradigm for interventional radiology in the United States incorporates four years of training in diagnostic imaging. A foundation in image interpretation is essential for the safe practice of interventional radiology.

Unfortunately, diagnostic radiologists and imaging educators are also few in number in resource-limited settings. For instance, prior to RAD-AID, a non-profit organization serving imaging needs worldwide, Guyana had no radiology training program. In the 20 francophone countries in Africa, there are 117 radiologists. Some Asian countries have one radiologist per million population

. To increase the number of interventional radiologists, the number of trained diagnostic radiologists also needs to increase. Though the current number of radiologists is inadequate, continued growth is likely and will promote better access to interventional radiology.

Adapting procedures is one mechanism that can be used to overcome the challenges associated with the practice of resource-limited interventional radiology. When certain equipment is not available, many procedures can still be performed effectively and safely through alternative protocols and techniques. For instance, portal vein embolization through a trans-ileocolic approach has been successfully performed with hysterosalpingography catheters

. Percutaneous nephrostomy using only a trocar catheter is a viable alternative to the typical needle/wire/dilator/catheter combination

. Gastrostomy tube placements and vascular malformation corrections have been successfully performed with ultrasound

. Ethanol ablation of hepatocellular carcinoma has been shown to be an alternative to thermal ablation

. Adaptations to “high cost” interventional radiology procedures indicate hope for the practice of interventional radiology throughout the world. With continued innovation, interventional radiology procedures can be practiced in settings outside of the typical modern procedural suite.

Training initiatives can also aid the spread of interventional radiology to resource limited regions. Through offering webinars and open-access training documents, interventional radiologists can teach basic procedures to providers in remote settings. Simple biopsies and drainages, vascular access, and embolization procedures are excellent opportunities for low-cost, minimally invasive, treatments.

Ultrasound and fluoroscopy are relatively inexpensive, ranging $10,000-to-$200,000 and $20,000-to-$80,000, respectively, and can be used for many procedures

. Though the needs of communities in North America are very different compared to places, such as Sub-Saharan Africa, re-evaluation and assessment of local needs can be met through tailored teachings in more advanced procedures

. Volunteer-based efforts led by non-profit organizations, such as RAD-AID, have focused on developing a global interventional radiology curriculum. Collaborations with Ethiopia, Ghana, Guyana, Kenya, Nigeria, and Vietnam have resulted in regular webinars and workshops. Through volunteerism, there is ample opportunity for interventional radiologists to contribute to efforts such as these initiatives.

The practice of interventional radiology faces several hurdles to becoming a global practice. Through the adaptation of procedures and the education of practitioners, the spread of interventional radiology to resource-limited settings is possible. Interventional radiologists will continue to display ingenuity through creative procedural adaptations and teaching modalities. In the future, maybe a rider will, again, fall from his motorcycle. Not only will he be able to receive high-quality and timely imaging, but he will also be able to receive a high-efficacy percutaneous procedure for treatment: a radiology procedure that has yet to be realized!

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Articles

What will it take to bring interventional radiology to these areas?

The Feasibility of Global Interventional Radiology: Opportunities in Resource-Limited Settings

Stroke is the leading cause of disability and the fifth leading cause of death in the United States. Despite the significant morbidity and costs, stroke therapy recommendations have not been well-established until recently, and radiology now plays a central role in the treatment of those patients.

Radiologists are ideally positioned to practice stroke intervention, given their acumen with image interpretation and experience with endovascular therapies. Formerly, the paradigm treatment for ischemic stroke consisted of intravenous thrombolytic therapy, which is easy to administer, typically in the setting of the emergency department. Recently, several randomized clinical trials suggested that endovascular thrombectomy provides superior outcomes.

In particular, the MR CLEAN trial, a multi-center clinical trial involving 233 stroke patients randomized to an endovascular treatment arm, revealed endovascular thrombectomy within six hours after stroke onset was effective and safe. Patients in the endovascular arm achieved improved functional outcomes in 83 percent of cases compared to 19 percent in the medical management arm. Interventional radiologists performed the majority of the thrombectomies in this trial.

CT Predicts Stroke Patients Benefitting From Endovascular Thrombectomy

Four other ongoing trials were terminated early, given the results of the MR CLEAN trial (1). The other four trials (ESCAPE, EXTEND-1A, SWIFT PRIME, REVASCAT), despite premature termination, also demonstrated evidence that significantly better outcomes could be achieved with thrombectomy compared to medical management. Accordingly, the American Hospital Association guidelines changed in 2015, engendering many hospitals to offer this service. The updated guidelines stated a Class 1a recommendation for the use of thrombectomy for anterior circulation large vessel occlusion strokes, up to six hours since the patient was last known well.

Unfortunately, the existing trained radiologist workforce and infrastructure of the healthcare system have not been adequate to meet the demand to deliver safe and timely treatment; high volume practitioners have been necessary to achieve the best clinical outcomes, but eligible patients have been infrequent enough to adequately sustain practice volume.

Specialized stroke care centers, thereby, have been developed for endovascular interventions as a means to funnel patients to high-volume practitioners. Similar models for cardiac ischemia, trauma, and pediatric critical care exist. Despite these efforts, disparity between thrombectomy demand and capable-physician supply still persists. Thrombectomy is currently only available to 2 percent-to-3 percdent of eligible patients in the United States. The current thrombectomy rate is 3 per 100,000 people and is expected to grow to 24 per 100,000 person-years, given the new guidelines (2).

Given these demands, accompanied by the delayed treatment time for transferring patients to designated stroke centers, alternative models have been proposed to train more radiologists to become capable of safely providing these specialized therapies. The traditional training paradigm for diagnostic radiology residents planning to specialize in interventional neuroradiology (INR) entails a neuroradiology fellowship, followed by an INR fellowship. Similarly, in order to practice INR, most interventional radiology residents are required to complete neuroradiology and INR fellowships.

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The Society of Interventional Radiology has championed a new training pathway where proctors train interventional radiologists. This pathway is suggested to be comparable to conventional neurointerventional fellowships and, therefore, serves as an alternative pathway to provide radiologists with the experience necessary to safely perform acute stroke interventions. A proctor needs to have performed 50 acute ischemic stroke cases as a primary operator, with at least two years of practice data with outcomes meeting national standards. Options for learning from a proctor could include one of the following three options (3):

Hands-on training not limited to interventional techniques, but also including workup before and after management for thrombectomy

Full-time training at a different institution, given the unpredictable case rate for stroke care

Travel consultant, where the proctor travels to institution to provide hands-on training

A case study at Johns Hopkins University (JHU) demonstrated success with this model. JHU recruited an INR physician to teach four interventional radiologists how to perform cerebral thrombectomies. The trainees were available for six months, and the INR physician was flown-in by helicopter for each eligible thrombectomy case. Upon completion of training, 35 of the stroke cases were reviewed, and compared to the quality guidelines outlined in the Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials (HERMES) meta-analysis published in 2016.

JHU 90-day mortality was 14 percent while HERMES was 15.3 percent. Therefore, upon being trained, the interventional radiologists had 90-day mortality ratings similar or better than the current benchmark (4). As demonstrated by the previous case study, and building upon their expertise in imaging and image-guidance, radiologists are able to acquire the skillset necessary to safely perform endovascular treatment in a short timeframe.

In summary, the morbidity and mortality of stroke is a detriment to patients and society, and, until recently, treatment attempts have often been ineffective or limited to a select group of patients. An immense opportunity now exists for radiologists to manage acute stroke patients with endovascular therapy and achieve excellent outcomes for many patients up to six hours after stroke onset.

Currently, the infrastructure of the healthcare system faces challenges in its ability to pair a capable physician and a patient in need. Radiologists are, however, ideally situated to contribute to this treatment revolution and lessen the disparity between the demand and the access for endovascular stroke therapy.

Vadlamudi V. Updates on Endovascular Therapy for Acute Ischemic Stroke. SIR-RFS Webinar. June 5, 2018.

. A population-based incidence of acute large vessel occlusions and thrombectomy eligible patients indicates significant potential for growth of endovascular stroke therapy in the USA. 

Sacks, D, AbuAwad, M, Ahn, S, et al. Society of Interventional Radiology Training Guidelines for Endovascular Stroke Treatment. 

Journal of Vascular and Interventional Radiology

SIR: Stroke treatment training program improves outcomes.

Interventional radiologists are uniquely positioned to practice stroke intervention. 

The Changing Landscape of Interventional Neuroradiology

Interventional Radiology has grown exponentially in recent years. Embolization procedures were first performed in 1970. Three years later, balloon angioplasties were being performed. Then, in the 1980s, complex interventions, such as Transjugular Intrahepatic Portosystemic Shunt (TIPS) placements were introduced

. These therapies are now offered in nearly every hospital. Such growth has been facilitated by advances in technology, combined with the creativity of practitioners. Evolving advances in augmented reality, artificial intelligence (AI), imaging modalities, robotics, and procedural techniques will play a big role in the future and facilitate further exponential growth.

In augmented reality, virtual images can be seen alongside real images. In contrast to virtual reality where the field of vision includes no real images, augmented reality offers the ability to maneuver objects and interact with the real world. This powerful development has wide-ranging applications for image-guided interventions. For example, an interventional radiologist could visualize vital signs within the same field of vision, overlying the patient during a critical intervention. These numbers could potentially appear on command when performing a key step of a procedure or when the radiologist has a concern.

Augmented and Virtual Reality – Radiology at the Center of Medical Technology

Needle placement or a procedure with an image-guided device is another application. For instance, the operator could also view a fused ultrasound image, during simultaneous visualization of needle insertion and ultrasound probe manipulations. Augmented reality can also be used to visualize anatomy underneath procedural drapes to guide an intervention when there is poor sonographic penetration or fluoroscopic guidance is insufficient. For example, a projected 3D hologram, recreated from a pre-programmed CT scan, can help the radiologist identify – and avoid – key structures during a percutaneous intervention, which may otherwise be invisible.

Recent developments in AI represent additional revolutionary opportunities of growth in the current and future practice of image-guided interventions. Utilizing AI, outcomes of interventions can be more accurately and quickly predicted, improving patient outcomes. Machine learning algorithms will be able to augment the interventional radiologist in guiding treatment decisions and selecting patient populations that would benefit most from interventions in areas, such as interventional oncology, where multimodal therapies abound.

Other future applications will include intraprocedural augmentation for the interventional radiologist. AI will enhance image guidance through anatomical recognition, to facilitate interventions and guide the operator through complex anatomy. Lastly, promising applications exist in the treatment of patients requiring time-sensitive interventions. Conditions, such as strokes and pulmonary embolisms, have been described to benefit from AI’s impact on expediting recognition and throughput to improve patient outcomes

Furthermore, continued enhancement of current image-guidance modalities and development of new ones will enhance future procedural practice. Limitations of current imaging modalities in interventional radiology include two-dimensionality and, oftentimes, radiation exposure. One new imaging guidance modality currently being pioneered is Fiber Optic RealShape (FORS)

. This imaging technology utilizes catheters embedded with light sensing technology. Currently, physicians are challenged by tortuous and diseased vasculature, which is difficult to visualize in 2D and often presents technical challenges to operators driving the catheter. Technologies, such as FORS and other evolving modalities, could optimize vascular imaging guidance, drastically decrease the procedural time, and radiation exposure for interventions, drastically increasing the safety for patients and practitioners alike in the future.

Another area with future potential in imaging-guided interventions is robotics, which has already been integrated into many fields of medicine. Oftentimes, in order for robotic systems to flourish in utilization, there must be a proven clinical benefit. For example, the DaVinci Surgical System results in smaller incision sites and higher surgical accuracy. These factors justify the cost.

Robotics have been applied to many endovascular procedures. Uterine artery embolization, cardiac ablation, and aneurysm repair have all been successfully performed with robotic navigation systems. Radiographic procedures are uniquely positioned to benefit from robotics due to added benefits to the operators. The interventionalists can work in a separate room from the procedural suite, thereby shielding them from radiation exposure and musculoskeletal injury from heavy protective aprons. More research, however, is needed to justify the cost of such systems, but it is expected that robotics will become more prominent in interventional suites. It is essential that benefits to the operator safety will not compromise patient outcomes, and quality-control studies continue to be rigorously applied and performed.

Lastly, the scope of practice of interventional radiology itself is expanding, as well. In addition to advancements in existing procedures and techniques, interventional radiologists are developing new procedures to address conditions, such as arthritis, obesity, and benign prostatic hypertrophy. Many of these procedures have been validated in small scale clinical trials. Chronic arthritis pain is being managed through embolization of hyperemic synovial tissue

. The left gastric artery has been embolized to decrease fundus blood flow, thereby restricting growth of ghrelin-producing cells and decreasing appetite

. Radiologists can also treat lower urinary tract symptoms through decreasing the size of the prostate with embolization

. Endovascular approaches continue to be identified as a way to treat conditions formerly managed with invasive surgeries and medication therapies. The future is bright as the value proposition of interventional radiology offering minimally invasive, high-quality, low-complication, cost-effective therapies aligns extremely well with the future of medicine and healthcare.

In summary, advancements in technology will foster improvements in efficiency, efficacy, and safety for interventional radiology and image-guided interventions. The degree of innovation and changing practice patterns will continue to be exponential, alongside exponential growth in technology. Interventional radiologists will be presented with ample opportunity to adapt and invent. This is an exciting challenge, and will mean a brighter future for patients.

Midulla M, Pescatori L, Chevallier O, et al. Future of IR: Emerging Techniques, Looking to the Future…and Learning from the Past. 

Keshava S, Kalva S. Artificial Intelligence in Interventional Radiology. 

Mascini L. Operate Using Live, 3D Image-Guided Navigation of the Inner Body. Innovation Origins: Your Sneak Peak of the Future. October 24, 2019. 

https://innovationorigins.com/operate-using-live-3d-image-guided-navigation-of-the-inner-body/

Balga S, Piechowiak R, Hartman T, et al. Genicular Artery Embolization for the Treatment of Knee Pain Secondary to Osteoarthritis. 

Pirlet C, Ruzsa Z, Costerousse O, et al. Transradial Left Gastric Artery Embolization to Treat Severe Obesity: A Pilot Study. 

Pisco J, Pinheiro L, Bilhim T, et al. Prostatic Arterial Embolization for Benign Prostatic Hyperplasia: Short- and Intermediate-term Results. 

From augmented reality to virtual reality to robotics to new procedural techniques – the future of interventional radiology is bright.

John Cerne, BS

Articles

The Feasibility of Global Interventional Radiology: Opportunities in Resource-Limited Settings

The Changing Landscape of Interventional Neuroradiology

Future Trends and Technologies in Interventional Radiology: What to Expect