Myocardial delayed enhancement CT rivals MRI for detecting scar tissue in heart failure patients

Myocardial delayed enhancement (MDE) CT rivaled late gadolinium enhanced (LGE) MRI in the detection and classification of myocardial scar in patients with heart failure, according to a recent Radiology study. The results may help identify features of chronic heart failure.

Dual-energy CT has been shown to identify scar tissue with accuracy close to pathologic specimens and LGE MRI. But lead author, Yasutoshi Ohta, with Tottori University School of Medicine in Japan, and colleagues noted that MDE CT has been held back from widespread use in evaluating scar tissue in those with cardiomyopathies because of its lower sensitivity compared to MRI and concerns over increased radiation exposure.

Authors performed MDE CT and LGE MRI in 44 patients with heart failure between 2013 and 2016. Two readers determined the presence and patterns of MDE on iodine-density and virtual monochromatic (VM) images. The pair also measured contrast-to-noise ratio (CNR) and percentage signal intensity increase compared to normal myocardium. Diagnostic performance and area under the curve operating characteristic curve for MDE CT was measured for reader agreement.

Some 80 percent of patients (35 of 44) exhibited a focal area of LGE, while half of the group showed a nonischemic pattern. Thirteen demonstrated an ischemic pattern (30 percent).

Additionally, Iodine-density images achieved the highest CNR and resulted in the highest diagnostic performance in detecting MDE CT abnormality (92 percent sensitivity and 98 percent specificity)

Ohta and colleagues called out two big take-aways from the results.

“First, MDE was detected with high diagnostic performance on iodine-density images and low-kiloelectron-volt VM images when compared with LGE MR images, they wrote. “Second, image quality measurements were higher for iodine-density imaging than for VM imaging.”

The team from Japan pointed out a few limitations of their study including its small cohort tested in a single-center. They noted the study would need to be replicated in a multicenter study, but their results demonstrated a positive step forward for MDE CT.

"MDE with dual-energy CT offers excellent detection and localization of enhancement, equal to that with LGE MRI, in patients with heart failure who necessitate investigation of underlying myocardial disease from ischemic to nonischemic cardiomyopathy,” Ohta et al. wrote.

Valentin Sinitsyn, with Lomonosov Moscow State University’s Department of Radiology in Russia largely echoed the concerns put forth by Ohta et al. in a related editorial. He wrote MDE dual-energy CT’s ability to differentiate between important causes of chronic heart failure indicates it “could be a very useful modality for the diagnostic work-up of such patients.”

“Further clinical studies and refinements in image analysis will help further clarify the role of dual-energy CT technology in the diagnosis of cardiomyopathy,” Sinitsyn added. “But, the value of MDE dual-energy CT of the myocardium appears promising.”