title: 201Tl SPECT abnormalities, documented at rest in dilated cardiomyopathy, are related to a lower than normal myocardial thickness but not to an excess in myocardial wall stress.
abstract: This study was aimed at determining whether the (201)Tl SPECT abnormalities documented in patients with dilated cardiomyopathy are related to a local excess in wall stress, which might act against the diastolic perfusion of myocardium.
  
  
  METHODS
  We included 6 healthy volunteers and 7 patients with idiopathic dilated cardiomyopathy who underwent (201)Tl SPECT at rest. On a 13-segment division of the left ventricle, indices of wall stress and tension were calculated at end-diastole by applying Laplace's law, with thickness and curvature radii being determined for each segment on 2 orthogonal MRI slices.
  
  
  RESULTS
  Among all patients, 21 analyzed segments had (201)Tl SPECT defects (D+) and 67 had none (D-). Myocardial thickness was lower in D+ (0.88 +/- 0.30 cm) than in D- (1.23 +/- 0.33 cm, P = 0.0002) or in segments from healthy volunteers (0.99 +/- 0.15 cm, P = 0.04). The index of end-diastolic wall tension was also lower in D+ (2.5 +/- 1.0 N.m(-1).mm Hg(-1)) than in D- (3.3 +/- 1.1 N.m(-1).mm Hg(-1), P = 0.02) or in segments from healthy volunteers (3.2 +/- 1.2 .m(-1).mm Hg(-1)) P = 0.04). Last, the index of end-diastolic wall stress, determined by the ratio of wall tension index to myocardial thickness, was equivalent in D+, in D-, and in segments from healthy volunteers (respectively, 3.0 +/- 1.4, 2.8 +/- 1.2, and 3.2 +/- 1.6 hN.m(-2).mm Hg(-1)).
  
  
  CONCLUSIONS
  In patients with dilated cardiomyopathy, the abnormalities documented by (201)Tl SPECT at rest are related to a lower than normal wall thickness and not to an excess in wall stress or tension. Therefore, partial-volume effects are likely to induce these abnormalities, and they may be unrelated to any insufficiency of myocardial perfusion.
authors.affiliation: Department of Nuclear Medicine, Unité Propre de Recherche de l'Enseignement Superieur-Equipe d'Accueil 3447, Centre Hospitalier Universitaire, Nancy, France. n.hassan-sebbag@chu-nancy.fr
authors.forename: Nathalie
authors.initials: N
authors.lastname: Hassan
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Escanyé
authors.forename: Yves
authors.initials: Y
authors.lastname: Juillière
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Marie
authors.forename: Nicolas
authors.initials: N
authors.lastname: David
authors.forename: Pierre
authors.initials: P
authors.lastname: Olivier
authors.forename: Adey
authors.initials: A
authors.lastname: Ayalew
authors.forename: Gilles
authors.initials: G
authors.lastname: Karcher
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Stolz
authors.forename: Alain
authors.initials: A
authors.lastname: Bertrand
mesh_terms: D002311:Cardiomyopathy, Dilated / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D003971:Diastole; D005260:Female; D006352:Heart Ventricles / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D019047:Phantoms, Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012146:Rest; D013318:Stroke Volume; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000000981:diagnostic imaging; D016277:Ventricular Function, Left
chemical_list: D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes