TC-99M CARDIAC SCINTIGRAPHY IN AMYLOIDOSI S - CORRELATIONS WITH DOPPLER-ECHOCARDIOGRAPHY

Technetium 99m cardiac scintigraphy as practiced at present for diagno sing amyloisodid only provides a visual semi-quantitative assessment o f uptake of the isotope. To improve the diagnostic accuracy of the met hod, the authors evaluated prospectively a personal technique of scint igraphy quantification based on early images obtained at the 20th minu te in 15 patients with neuropathic amyloidosis. Doppler echocardiograp hic 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 scintigr aphic index and interventricular septal or posterior wall thickness me asured by echocardiography was poor. These results obtained in 15 pati ents with neuropathic amyloidosis suggest that the scintigraphic index measured at the 20th minute is discriminatory and allows identificati on of those patients with cardiac involvement. On the other hand, the correlations with echocardiographic wall thickness are poor. Technetiu m 99m cardiac scintigraphy with this technique of quantification is a useful tool for diagnosing cardiac amyloidosis, especially when echoca rdiography is difficult to interpret.