The Auxiliary Role of Cardiac Magnetic Resonance Feature-Tracking Parameters in the Differentiation between Cardiac Amyloidosis and Constrictive Pericarditis

Objectives. Cardiac amyloidosis (CA) and constrictive pericarditis (CP) are described as the differential diagnoses of restrictive hemodynamic alterations of the heart. We aimed to explain cardiac magnetic resonance (CMR) imaging findings (especially feature tracking (FT)) of CA and CP cases and compare them with healthy controls. Moreover, we evaluated the role of biventricular FT parameters in differentiating CA from CP. Methods. Thirty-eight patients who underwent CMR between February 2016 and January 2018 with the ultimate diagnosis of CA (19 patients) or CP (19 patients) were enrolled. We included biopsy-proven light-chain amyloidosis patients. The data of 28 healthy controls were utilized for comparison. The patients were followed up for 8–23 months to register mortality and their surveillance. All CMR morphological and functional data, including FT parameters, were recorded and analyzed. Results. Of only 13/19 (68.4%) CA patients who had the follow-up data, 11/13 (84.6%) died. One of The CP patients (5.3%) expired during the follow-up. Significant between-group differences were noted concerning the biventricular ejection fraction as well as global longitudinal, circumferential, and radial strain values ( <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mi>P</a:mi> <a:mi>s</a:mi> <a:mo><</a:mo> <a:mn>0.001</a:mn> </a:math> ). The left ventricular (LV) global longitudinal strain (GLS) ≤10% was detected in 13/19 (68.4%) of the CA and 1/19 (5.3%) of CP cases ( <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mi>P</c:mi> <c:mo><</c:mo> <c:mn>0.001</c:mn> </c:math> ). A significant difference between the mean value of the LVGLS and LV global circumferential strain (GCS) of the basal LV level compared to the mid and apical levels was observed ( <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" id="M3"> <e:mi>P</e:mi> <e:mi>s</e:mi> <e:mo><</e:mo> <e:mn>0.001</e:mn> </e:math> ) in the CA patients. The differences between the mean LVGLS and the GCS measures of the mid and apical LV levels were not significant ( <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" id="M4"> <g:mi>P</g:mi> <g:mo>=</g:mo> <g:mn>1</g:mn> </g:math> and <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" id="M5"> <i:mi>P</i:mi> <i:mo>=</i:mo> <i:mn>0.06</i:mn> </i:math> , respectively). Conclusions. In our study, CA and CP severely disrupted ventricular strains. Biventricular GLS was meaningfully lower in the CA subjects. Therefore, strain analysis, especially in the longitudinal direction, could be helpful to differentiate CA from CP.