Imaging Tracer Allows Early Evaluation of Abdominal Aortic Aneurysm

With the development of a novel tracer, single-photon emission computed tomography/computed tomography (SPECT/CT) imaging could potentially be used to assess a patient’s rupture risk for abdominal aortic aneurysm (AAA), allowing better management of this disease.

Examples of ex vivo photography (A) and autoradiography (B) of aortae and carotid arteries from apoE-/-mice with CaCl2-induced carotid aneurysm injected with 99mTc-RYM1 without (left) and with the pre-injection of an excess of MMP inhibitor, RYM (right). Courtesy of Jakub Toczek et al., Yale Cardiovascular Research Center, New Haven, Conn.

Researchers developed a water-soluble matrix metalloproteinase (MMP) inhibitor that formed the basis for a novel tracer, RYM1. The new tracer was compared with another MMP tracer in mouse models of aneurysm.

The study results showed that SPECT/CT imaging used with the new tracer, RYM1 labeled with Tc-99m, showed promise as a tool for managing AAA.

“Studies in mouse models of aneurysm showed that this tracer allows for imaging vessel wall biology with high sensitivity and specificity, and aortic tracer uptake in vivo correlates with vessel wall inflammation,” said Mehran M. Sadeghi, M.D., Yale Cardiovascular Research Center.

“There is no effective medical therapy for AAA, and current guidelines recommend invasive repair of large AAA. However, the morbidity and mortality remain high, so better tools for AAA risk stratification are needed,” Sadeghi said.

Looking ahead, he added, “Fulfilling the potential of molecular imaging in improving patient care and advancing research is critically dependent on the development of novel tracers with real potential for clinical translation. . . . Further development of RYM1-based imaging could expand the applications of molecular imaging and nuclear medicine, and improve patient management in a wide range of diseases.”

The research was published in The Journal of Nuclear Medicine (doi: 10.2967/jnumed.116.188656).