Interventional radiology: Coming of age

Dr Rohan Sonawane Clinical Marketing – Healthcare Sector, Siemens

Interventional radiology (IR) is a highly advanced and comparatively newer speciality in the field of medicine. It combines the power of cutting-edge technology for high-end imaging with applications that help in treatment planning, navigation and guidance to improve clinical workflow efficiency and enhance procedural outcomes. The concept behind IR is to diagnose and treat patients using ‘minimally invasive’ techniques, so as to improve treatment quality and also offer solutions to people who are otherwise ‘unfit’ for open surgeries.

The basic aim of IR is to bring down the intra and post-operative morbidity and mortality, improve patient comfort during the procedure, reduce complications and thus enhance clinical outcomes of the treatment.

Using modalities such as fluoroscopy, CT and ultrasound, interventional radiologists perform complex cardiac, neuro, onco and other procedures under direct image guidance. Direct imaging improves physician confidence for diagnostic as well as therapeutic procedures. Smaller incisions, better patient compliance and shorter hospital stay make these procedures attractive for hospitals as well as for patients.

The field of IR can be broadly classified into four main categories:

1. Interventional Cardiology
2. Interventional Neuro-radiology
3. Interventional Oncology
4. Interventional Vascular procedures

Some common IR procedures and their brief descriptions are given below:

Coronary Angiography + Balloon Angioplasty with stent: Angiography is imaging the coronary vessels to look for life threatening blockages (cholesterol plaques). Clinically significant plaques can be treated with angioplasty and stent deployment. This is undoubtedly the most commonly performed IR procedure.

Fig: Endovascular aneurysm repair

Endovascular aneurysm repair (EVAR): AAA (Abdominal Aortic Aneurysm) can now be treated through percutaneous approach by passing the stent under continuous image guidance through femoral artery. There is no need for open abdominal surgery with this innovative technique.

Trans Arterial Chemo Embolisation (TACE): Delivering cancer treatment directly to a tumour through its blood supply requires exact identification of the tumour feeding vessel. This vessel is then blocked with chemoembolisation agent. Due to a selective and specific blocking of the tumor feeding vessel, surrounding normal tissue is spared.

Fig: Colour-coded image from dynamic information, showing the history of contrast media movement through the vessels and providing a better understanding of the flow within the pathology.

CT guided real time biopsy + Radiofrequency Ablation: This involves taking a tissue sample from the area of interest for pathological examination under real time guidance. It is now possible to get real time 3D guidance with coronal, sagital and axial views to give interventional radiologists the exact location and depth of needle for precise biopsy and ablation treatments. Siemens is currently the only one to provide this unique solution.

Inferior vena cava (IVC) filter: This involves metallic filters placed in the inferior vena cava to prevent propagation of deep venous thrombus into pulmonary vasculature.

Vertebroplasty: Percutaneous injection of biocompatible bone cement inside fractured vertebrae under image guidance.

TIPS: Placement of a Transjugular Intrahepatic Porto-systemic Shunt (TIPS) for management of select patients with critical end-stage liver disease and portal hypertension.

Endovenous laser treatment of varicose veins: This is placement of thin laser fiber in varicose veins for non-surgical treatment of venous insufficiency.

Latest innovations in IR

3D imaging in the angiography suite: 3D acquisition is now possible in angiography suite, assisting the clinicians in planning the interventional procedures. It enables decision making at the point of diagnosis with additional CT like information and virtually avoids patient transfer to CT/MR. The interventionist gets immediate anatomical information helping him in quick post procedural evaluation. Also, due to less patient handling, there is lesser risk of hospital acquired infection (HAI) and improved patient comfort.

Siemens’ unique and flagship application Syngo DynaCT Cardiac™ is a 3D application that creates both 3D and 4D images of heart by rotational angiography right on the interventional procedure table. The acquired 2D images are then reconstructed to provide the complete 3D view of the cardiac anatomy.

syngo DynaCT Cardiac™ is useful in the interventional procedures for the treatment of ventricular arrythmias, visualisation of aortic root and coronary ostia in aortic valve replacement procedure and in few paediatric applications (visualisation of lung vessel tree after fontan surgery for hypoplastic left heart syndrome, visualisation of 3D anatomy of coarctation of aorta, assistance for ASD device closure etc.)

Dynamic Flow evaluation for Interventional Neurology:It is now possible to avail visualisation of a complete Digital Subtraction Angiography (DSA) run in full colour as a single image in the interventional suite.

This imaging is particularly useful in comparing pre- and post-treatment acquisitions where clinicians are trying to see how flow has changed not just through arteries, but also in the brain parenchyma. This info will also be of help in analysing complex flow patterns often seen in obstructive diseases with complicated collaterals as well as in arterio-venous fistula and malformations.

Fig: Structural and functional imaging with Neuro PBV in one place: Diagnosis- Evaluation- Treatment- Check

Neuro PBV

Neuro Parenchymal Blood Volume (PBV) allows for quantitative measurements to be undertaken and thus allowing the visualisation of the whole brain in 3D.

Benefits of Neuro PBV are:

• Visualise the PBV for the whole brain
• Compare regions of interest within different lobes
• Specific acquisition protocol
• Images available in under 40 seconds
• Functional monitoring during endovascular treatment
• Covering the entire brain
• Important monitoring tool in stroke treatment, vasospasm treatment, stent follow-up
• Valuable for direct tumour punctures

TACE, SIRT and RFA for Interventional oncology

Good image quality is indispensible for visualising fine vessels and devices during interventional oncology procedures, particularly as devices such as guide wires and catheters become increasingly smaller and harder to see with fluoroscopic imaging. Excellent 2D image quality as well as advanced 3D planning and navigation technologies to support interventional oncology procedure is thus a necessity.

A lineup of highly progressive imaging systems and advanced applications to support minimally invasive cancer treatment such as transarterial chemoembolisation (TACE), selective internal radiation therapy (SIRT) and radiofrequency ablation (RFA) are now frequently used for cancer treatments.

TACE involves selective injection of the embolising agent through exact identification of tumour-feeding vessel. Improved planning of embolisation procedures and immediate knowledge of procedure status is possible in IR suite. By clearly highlighting marked vessel as a graphical overlay in the live fluoro image, embolisation is quick and precise. SIRT is a complex therapy that involves selective administration of radioactive microspheres under imaging guidance. In RFA treatment, pinpoint needle placement plays a crucial role for successful tumor ablation. Cutting-edge 3D guidance tools such as syngo iGuide from Siemens provide superb assistance for accurate needle navigation in RFA treatments.

For all these interventional procedures, there is no need to transfer patients to CT for imaging if the hospital is equipped with an IR suite. Hence, these solutions make the oncology procedures minimally invasive and maximally effective!

Future Roadmap: merger of surgery and interventions through hybrid approach!

Medicine is witnessing a fascinating trend of merger of cath labs with surgical suites i.e. hybrid operating rooms (OR). Surgery is progressively becoming less invasive and ORs are increasingly adapting to these changes. The growing convergence of surgery and imaging is particularly evident in fields such as cardiac, vascular and neurosurgery. More and more healthcare facilities are installing hybrid ORs capable of supporting both minimally invasive surgical as well as interventional procedures.

Equipped with highly advanced surgical management and imaging technologies, these modern ORs create unprecedented opportunities for improved surgical treatment and workflow optimisation. They also make good economic sense by decreasing post-operative hospital stay. Siemens was the first in the world to introduce Hybrid OR system with a robotic arm.

Concurrent bypass surgeries with angioplasty in one sitting are being performed in India as of now. Soon, we will also have TAVI (Trans Catheter Aortic Valve Implantation) procedures being conducted in India in Hybrid OR!