Evaluation of pectus excavatum indexes during standard cardiac magnetic resonance: Potential for single preoperative tool

Abstract

Purpose: Preoperative assessment of patients with pectus excavatum (PE) demands evaluation of malformation indexes, generally with chest computed tomography (CT). In addition, assessment of the cardiac impact of sternal depression has become a rule in high referral centers, thus requiring two independent imaging modalities and use ionizing radiation in a very young population. The objective of this study was to explore the agreement between chest CT and standard cardiac MR (CMR) for the evaluation of chest wall malformation indexes. Methods: We included consecutive patients with PE referred to undergo chest CT and CMR to establish surgical candidacy and/or to define treatment strategies. Both CT and CMR were performed at full-expiration. In both modalities, the Haller index (HI) and the Correction index (CI) were calculated by two independent observers. In CMR, only scout images were used. Agreement was evaluated using intra-class correlation coefficients (ICC). Results: Fifty patients comprised the study population (median age 19.0 years) and underwent chest CT and CMR within the same month. CMR assessment of chest malformation indexes was reproducible, with a very good inter-observer agreement for HI [ICC 0.93 (0.88–0.96), p < 0.0001] and CI [ICC 0.91 (0.83–0.95), p < 0.0001]. CMR also had a very good agreement with chest CT for HI [ICC 0.90 (0.82–0.94), p < 0.0001] and CI measurements [ICC 0.93 (95% CI 0.88–0.96), p < 0.0001]. Conclusions: We demonstrated an excellent agreement between chest CT and standard CMR for the assessment of chest wall malformations, thus potentially enabling preoperative assessment of PE severity and cardiac involvement with a single diagnostic tool.