The contribution of 99mTc-pyrophosphate tomoscintigraphy in the evaluation of necrotic myocardial lesions.

Diagnostic contribution of Conventional Planar Scintigraphy (CPSc) and Single Photon Emission Computed Tomoscintigraphy (SPECT), using 99mTc-Pyrophosphate (99mTc-PYP), have been compared in 49 patients with either transmural (T.I., N = 40), or non-transmural (N.T.I., N = 9) infarction. Sensitivity ratios were, respectively for CPSc and SPECT, 75% and 100% in T.I., 78% and 88% in N.T.I. CPSc was non-diagnostic in 6 out of 49 patients, SPECT in only 1. Extent of the necrotizing process was better delineated on SPECT studies than on CPSc. Specificity of 99mTc-PYP tomoscintigraphy evaluated in a group of 6 young (under 40 years old) normal patients was 6/6 (100%). In nine out of ten additional patients without proven infarction who had underwent contrast coronarography within two weeks after a positive 99mTc-PYP SPECT study, significant stenosis (greater than 50%) were found on arteries supplying blood to pathologic territories as demonstrated on tomoscans. It is concluded that 99mTc-PYP SPECT is a very sensitive and specific way--better than CPSc--in the diagnosis as well as in the evaluation of the extent of necrotic myocardial process.