The Quarterly Journal of Nuclear Medicine and Molecular Imaging 2004 March;48(1):4-11

Copyright © 2009 EDIZIONI MINERVA MEDICA

lingua: Inglese

Classification of ischemic dysfunctional myocardium combining perfusion quantification and contractile reserve evaluation using nitrate-enhanced gated single photon emission computed tomography with dobutamine test

Sciagrà R. ¹, Leoncini M. ², Mennuti A. ³, Dabizzi R. P. ², Pupi A. ¹

¹ Unit of Nuclear Medicine, Department of Clinical Physiopatology University of Florence, Florence, Italy 2 Department of Cardiology “Misericordia e Dolce Hospital”, Prato, Italy 3 Unit of Nuclear Medicine “Misericordia e Dolce Hospital”, Prato, Italy

Aim. In ­patients ­with ischem­ic car­di­om­yo­pa­thy, the dif­fe­ren­ti­a­tion of dys­func­tion­al myo­car­di­um in ­scarred ver­sus hiber­nat­ing is over­sim­pli­fied. We eval­u­at­ed a ­more com­plex clas­sifi­ca­tion ­using an imag­ing tech­nique cur­rent­ly ­employed for viabil­ity detec­tion, hav­ing as ref­er­ence the post­re­vas­cu­lar­iza­tion out­come of dys­func­tion­al seg­ments.
Methods. In 35 ­patients, we per­formed gat­ed sin­gle-pho­ton emis­sion com­put­ed tomog­ra­phy (­SPECT) (rest­ing and ­nitrate-­enhanced ­study, the lat­ter ­with base­line and dobu­ta­mine acqui­si­tion) ­before revas­cu­lar­iza­tion. The out­come ­after revas­cu­lar­iza­tion was ­assessed by repeat­ing rest­ing gat­ed ­SPECT. Dysfunctional seg­ments with­out func­tion­al recov­ery in post­re­vas­cu­lar­iza­tion gat­ed ­SPECT ­were ­defined ­scar (­either non­trans­mu­ral or trans­mu­ral accord­ing to trac­er activ­ity); ­those ­with recov­ery ­were divid­ed in ­stunned (­unchanged ­uptake) or hiber­nat­ing (­improved post­re­vas­cu­lar­iza­tion activ­ity). This ref­er­ence clas­sifi­ca­tion was com­pared ­with the cat­e­gor­iza­tion ­based on prerevas­cu­lar­iza­tion gat­ed ­SPECT.
Results. Contractile ­reserve in dobu­ta­mine gat­ed ­SPECT dif­fer­en­tiat­ed ­scarred ­from ­viable seg­ments ­with 78% accu­ra­cy. Tracer activ­ity in ­nitrate imag­ing dis­tin­guished the ­degree of trans­mu­ral­ity. Nitrate-­induced activ­ity ­increase was sig­nif­i­cant­ly high­er (p<0.0001) in the hiber­nat­ing seg­ments (14.9±20.4%) ­than in trans­mu­ral (4.8±13.4%) non­trans­mu­ral ­scars (3.3±13%), or ­stunned seg­ments (2.2±8%). The pres­ence or ­absence of ­nitrate-­induced activ­ity ­increase pre­dict­ed the ­postrevas­cu­lar­iza­tion per­fu­sion chang­es in ­viable myo­car­di­um and dif­fer­en­tiat­ed hiber­nat­ing ­from ­stunned seg­ments. The pre­re­vas­cu­lar­iza­tion clas­sifi­ca­tion ­showed a ­good agree­ment ­with the ref­er­ence cat­e­gor­iza­tion (κ=0.50).
Conclusion. Combining con­trac­tile ­reserve eval­u­a­tion and per­fu­sion quan­tifi­ca­tion with­in a sin­gle ­study ­with base­line-­nitrate gat­ed ­SPECT and dobu­ta­mine ­test it is pos­sible to ­achieve a com­pre­hen­sive clas­sifi­ca­tion of dys­func­tion­al seg­ments.