A second-generation robotic angiography system produces noticeably better images at a lower radiation dose during minimally invasive treatments for liver cancer, according to new research.
Hepatocellular carcinoma (HCC) makes up approximately 80% of liver cancers. It is the fourth most common cause of cancer-related death worldwide, killing more than 600,000 people every year. An aging population and increasing obesity and hepatitis C infections are factors in the growing HCC rate in the United States, where the number of cases has more than tripled since the 1980s.
Current treatments include surgery, liver transplantation and radiofrequency ablation. But many patients are not candidates for surgery or transplantation or have had chronic liver disease and other comorbidities. For these patients, conventional transarterial chemoembolization (cTACE) is a valuable treatment option.
In cTACE, a catheter is threaded to the site of the tumor under fluoroscopic guidance. Chemotherapeutic drugs are released followed by embolic agents that block tumor-feeding vessels, starving the tumor of blood.
"Conventional TACE has become the mainstay of treatment for unresectable HCC and a potential palliative tool for treatment of hepatic metastases," said study co-author Thomas J. Vogl, MD, a radiologist from the Institute of Diagnostic and Interventional Radiology at Goethe University in Frankfurt, Germany.
Comparing First, Second Generation Robotic Systems
For the study, Dr. Vogl and colleagues compared first and second generation advanced robotic angiography systems in terms of radiation dose and image quality during cTACE of malignant hepatic tumors. Robotic systems assist the interventionalist in performing cTACE and other procedures. The systems have joysticks and touchscreen controls that allow a high degree of precision when performing the procedure.
Researchers divided 106 HCC patients receiving cTACE procedures into two groups of 53. The patients in each group has a similar number of lesions in similar locations in their livers.
The first group underwent cTACE on the first-generation robotic system, while the second-generation robotic system was used on the second group. Improved features of the second-generation system include a refined crystalline detector system for enhanced noise reduction and advanced software for lowering radiation dose.
The researchers compared fluoroscopy-related radiation dose and the dose for digital subtraction angiography (DSA), a fluoroscopic technique used for visualizing blood vessels in which radiopaque structures like bones are digitally subtracted from the image, allowing for a more accurate depiction of the blood vessels.
Three radiologists performed blinded image quality analysis.
The second-generation provided higher image quality at a more than 50% lower radiation dose.
"The most current generation robotic angiography equipment allows significant dose reductions while significantly improving image quality in fluoroscopy and DSA image guidance during conventional TACE treatment of malignant hepatic tumors," Dr. Vogl said.
To illustrate the difference, Dr. Vogl displayed side-by-side images from the two systems. The images from the second-generation system were notably clearer.
"If you compare it to the older system, the new system has much better vessel delineation, especially in the upper part of the liver," he said.
For More Information:
View the RSNA 2020 session Conventional Transarterial Chemoembolization (cTACE) in Malignant Hepatic Tumors: First Generation versus Second Generation of Robotic Angiograhy System for Real-Time Image Guidance Regarding Radiation Dose and Image Quality — SSVI05 at RSNA2020.RSNA.org.
