[Technetium TC 99m pyrophosphate myocardial scintigraphy in amyloidosis. Correlations with Doppler echocardiography]

Technetium 99m cardiac scintigraphy as practiced at present for diagnosing amyloisodid only provides a visual semi-quantitative assessment of uptake of the isotope. To improve the diagnostic accuracy of the method, the authors evaluated prospectively a personal technique of scintigraphy quantification based on early images obtained at the 20th minute in 15 patients with neuropathic amyloidosis. Doppler echocardiographic studies indicated that 9 patients had cardiac involvement whilst 6 were free of cardiac amyloidosis. The index of isotopic uptake (ratio of cardiac/abdominal uptake) was 0.44 to 1.58 in the first group and 0.09 to 0.31 in the second group. The correlation between the scintigraphic index and interventricular septal or posterior wall thickness measured by echocardiography was poor. These results obtained in 15 patients with neuropathic amyloidosis suggest that the scintigraphic index measured at the 20th minute is discriminatory and allows identification of those patients with cardiac involvement. On the other hand, the correlations with echocardiographic wall thickness are poor. Technetium 99m cardiac scintigraphy with this technique of quantification is a useful tool for diagnosing cardiac amyloidosis, especially when echocardiography is difficult to interpret.