title: Analyzing myocardial torsion based on tissue phase mapping cardiovascular magnetic resonance.
abstract: BACKGROUND
  The purpose of this work is to analyze differences in left ventricular torsion between volunteers and patients with non-ischemic cardiomyopathy based on tissue phase mapping (TPM) cardiovascular magnetic resonance (CMR).
  
  
  METHODS
  TPM was performed on 27 patients with non-ischemic cardiomyopathy and 14 normal volunteers. Patients underwent a standard CMR including late gadolinium enhancement (LGE) for the assessment of myocardial scar and ECG-gated cine CMR for global cardiac function. TPM was acquired in short-axis orientation at base, mid, and apex for all subjects. After evaluation by experienced observers, the patients were divided in subgroups according to the presence or absence of LGE (LGE+/LGE-), local wall motion abnormalities (WM+/WM-), and having a preserved (≥50%) or reduced (<50%) ejection fraction (EF+/EF-). TPM data was semi-automatically segmented and global LV torsion was computed for each cardiac time frame for endocardial and epicardial layers, and for the entire myocardium.
  
  
  RESULTS
  Maximum myocardial torsion was significantly lower for patients with reduced EF compared to controls (0.21 ± 0.15°/mm vs. 0.36 ± 0.11°/mm, p = 0.018), but also for patients with wall motion abnormalities (0.21 ± 0.13°/mm vs. 0.36 ± 0.11°/mm, p = 0.004). Global myocardial torsion showed a positive correlation (r = 0.54, p < 0.001) with EF. Moreover, endocardial torsion was significantly higher than epicardial torsion for EF+ subjects (0.56 ± 0.33°/mm vs. 0.34 ± 0.18°/mm, p = 0.039) and for volunteers (0.46 ± 0.16°/mm vs. 0.30 ± 0.09°/mm, p = 0.004). The difference in maximum torsion between endo- and epicardial layers was positively correlated with EF (r = 0.47, p = 0.002) and age (r = 0.37, p = 0.016) for all subjects.
  
  
  CONCLUSIONS
  TPM can be used to detect significant differences in LV torsion in patients with reduced EF and in the presence of local wall motion abnormalities. We were able to quantify torsion differences between the endocardium and epicardium, which vary between patient subgroups and are correlated to age and EF.
authors.affiliation: Jacobs University Bremen, Bremen, Germany. teodora.chitiboi@mevis.fraunhofer.de.|Fraunhofer MEVIS, Bremen, Germany. teodora.chitiboi@mevis.fraunhofer.de.
authors.forename: Teodora
authors.initials: T
authors.lastname: Chitiboi
authors.affiliation: Department of Radiology, Northwestern University, Chicago, IL, USA.
authors.forename: Susanne
authors.initials: S
authors.lastname: Schnell
authors.affiliation: Department of Radiology, Northwestern University, Chicago, IL, USA.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Collins
authors.affiliation: Department of Radiology, Northwestern University, Chicago, IL, USA.
authors.forename: James
authors.initials: J
authors.lastname: Carr
authors.affiliation: Department of Radiology, Northwestern University, Chicago, IL, USA.
authors.forename: Varun
authors.initials: V
authors.lastname: Chowdhary
authors.affiliation: Department of Radiology, Northwestern University, Chicago, IL, USA.
authors.forename: Amir Reza
authors.initials: AR
authors.lastname: Honarmand
authors.affiliation: Fraunhofer MEVIS, Bremen, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Hennemuth
authors.affiliation: Jacobs University Bremen, Bremen, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Linsen
authors.affiliation: Jacobs University Bremen, Bremen, Germany.|Fraunhofer MEVIS, Bremen, Germany.
authors.forename: Horst K
authors.initials: HK
authors.lastname: Hahn
authors.affiliation: Department of Radiology, Northwestern University, Chicago, IL, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D009202:Cardiomyopathies / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D003287:Contrast Media; D004699:Endocardium / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D015588:Observer Variation; D010496:Pericardium / Q000473:pathology / Q000503:physiopathology; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013318:Stroke Volume; D054159:Torsion, Mechanical; D016277:Ventricular Function, Left
chemical_list: D003287:Contrast Media
keywords: Cardiovascular magnetic resonanace; Myocardial velocities; Non-ischemic cardiomyopathy; Tissue phase mapping; Torsion