title: Comparison between (99m)Tc-diphosphonate imaging and MRI with late gadolinium enhancement in evaluating cardiac involvement in patients with transthyretin familial amyloid polyneuropathy.
abstract: OBJECTIVE
  Cardiac involvement is not rare in systemic amyloidosis and is associated with poor prognosis. Both (99m)Tc-diphosphonate imaging and cardiac MRI with late gadolinium enhancement are considered valuable tools in revealing amyloid deposition in the myocardium; however, to our knowledge, no comparative study between the two techniques exists. We compared findings of these two techniques in patients with transthyretin-familial amyloid polyneuropathy (FAP).
  
  
  METHODS
  Eighteen patients with transthyretin-FAP underwent (99m)Tc-diphosphonate imaging and MRI with late gadolinium enhancement. Images were visually evaluated by independent readers to determine the presence of radiotracer accumulation or late gadolinium enhancement-positive areas at the level of cardiac chambers.
  
  
  RESULTS
  Interobserver agreement ranged from moderate to very good for (99m)Tc-diphosphonate imaging findings and was very good for findings of MRI with late gadolinium enhancement. Left ventricle (LV) radiotracer uptake was found in 10 of 18 patients, whereas LV late gadolinium enhancement-positive areas were found in eight of 18 patients (χ(2) = 0.9; p = 0.343). One hundred fifty-nine LV segments showed (99m)Tc-diphosphonate accumulation, and 57 LV segments were late gadolinium enhancement positive (p < 0.0001). Radiotracer uptake was found in the right ventricle (RV) in eight patients and in both atria in five patients, whereas MRI showed that RV was involved in three patients and both atria in six patients; the differences were not statistically significant (RV, p = 0.07; atria, p = 1). Intermodality agreement between (99m)Tc-diphosphonate imaging and MRI ranged from fair to good.
  
  
  CONCLUSIONS
  Our study shows that, although (99m)Tc-diphosphonate imaging and MRI with late gadolinium enhancement have similar capabilities to identify patients with myocardial amyloid deposition, cardiac amyloid infiltration burden can be significantly underestimated by visual analysis of MRI with late gadolinium enhancement compared with (99m)Tc-diphosphonate imaging.
authors: Department of Radiological Sciences, University of Messina, Consolare Valeria 1, Messina 98100, Italy. fminutoli@unime.it
authors: Fabio
authors: F
authors: Minutoli
authors: Gianluca
authors: G
authors: Di Bella
authors: Anna
authors: A
authors: Mazzeo
authors: Rocco
authors: R
authors: Donato
authors: Massimo
authors: M
authors: Russo
authors: Emanuele
authors: E
authors: Scribano
authors: Sergio
authors: S
authors: Baldari
mesh_terms: D000328:Adult; D000368:Aged; D028227:Amyloid Neuropathies, Familial / Q000150:complications* / Q000175:diagnosis; D009202:Cardiomyopathies / Q000175:diagnosis* / Q000209:etiology; D004164:Diphosphonates; D005260:Female; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017556:Technetium Compounds; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D004164:Diphosphonates; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; D017556:Technetium Compounds; C090600:gadobutrol; C029045:technetium Tc 99m diphosphonate