Grating-based phase-contrast computed tomography (gb-PCCT) relies on x-ray refraction instead of absorption to generate high-contrast images in biological soft tissue. The aim of this study was to evaluate the potential of gb-PCCT for the depiction of structural changes in heart disease.
Four human heart specimens from patients with hypertensive disease, ischemic disease, dilated heart disease, and cardiac lipomatosis were examined. The gb-PCCT setup consisted of an x-ray tube (40 kV, 70 mA), grating-interferometer, and detector, and allowed simultaneous acquisition of phase- and absorption-contrast data. With histopathology as the standard of reference, myocardium (MC), fibrotic scar (FS), interstitial fibrosis (IF), and fatty tissue (FT) were visually and quantitatively evaluated. Systematic differences in absorption- and phase-contrast Hounsfield units (HUabs and HUp) were assessed.
Thirteen corresponding cross-sections were included, and MC, FS, IF, and FT were found in 13 (100%), 4 (30.8%), 7 (53.8%), and 13 (100%) cross-sections, respectively. Mean HUp/HUabs were 52.5/54.1, 86.6/69.7, 62.4/62.3, and −38.6/−258.9 for MC, FS, IF, and FT, respectively. An overlap in HUabs was observed for MC and IF (P = 0.84) but not for HUp (P < 0.01). Contrast-to-noise ratios were significantly higher in phase- than in absorption-contrast for MC/FT (35.4 vs 7.8; P < 0.01) and for MC/FS (12.3 vs 0.2; P < 0.01).
Given its superior soft tissue contrast, gb-PCCT is able to depict structural changes in different cardiomyopathies, which can currently not be obtained by x-ray absorption-based imaging methods. If current technical limitations can be overcome, gb-PCCT may evolve as a powerful tool for the anatomical assessment of cardiomyopathy.
From the *Institute of Clinical Radiology, Ludwig-Maximilians University Hospital; †Department of Physics and Institute of Medical Engineering, Technical University of Munich; and ‡Institute of Pathology, Ludwig-Maximilians University Hospital, Munich, Germany.
Received for publication January 23, 2017; and accepted for publication, after revision, July 9, 2017.
The authors acknowledge the financial support by the DFG Clusters of Excellence, Munich Centre for Advanced Photonics, and Hans and Klementia Langmatz Foundation. The funders had no role in the study design, data collection, and analysis or preparation of the manuscript.
Correspondence to: Susan Notohamiprodjo, MD, Institute of Clinical Radiology, University Hospital of Munich, Nußbaumstraße 20, 80336 Munich, Germany. E-mail: Susan.Notohamiprodjo@med.lmu.de.