To validate the importance of 67Ga imaging to diagnose activity in rheumatic fever carditis and in the follow-up of treated patients with the disease.
Thirty patients with rheumatic fever were studied. Fifteen males and 15 females aged 7 to 39 years old (median 16 years), were submitted to 67Ga imaging. The patients were divided into two groups: GA--20 patients who received only clinical treatment and GB--11 patients (one from group A) submitted to surgical biopsy. In 12 patients from GA, sequential 67Ga imaging were also realized for the therapeutic follow-up. Fifty-five 67Ga images were reviewed subjectively by experienced observers and a semi-quantitative analysis processed in a dedicated computer was performed with ROI's of 10 x 20 pixels over the projection of the heart and right lung in 22 negative and 33 positive studies.
Group A--In 19 patients (95%) the 67Ga uptake matched with the clinical evidence, EGC and echocardiogram results. In one patient (5.0%) the 67Ga study was negative, but there were clinical and EKG evidence of activity of the disease; from these data this case was then considered as false negative. Group B--In 11 patients submitted to surgical biopsy, the clinical-scintigraphic-histologic correlation matched in 10 cases and mismatched in one. The semi-quantitative analysis of the 67Ga uptake with ROI's over the topography of the heart and right lung showed an percentage index heart x right lung of 114.5 +/- 17.5% (2 s.d.) in normals and 158 +/- 30% (2 s.d.) in patients with active carditis: these data had value in the therapeutic follow-up of 12 patients from GA, where occurred good correlation, in every case, of the 67Ga uptake index and clinical evolution and EKG findings.
The 67Ga imaging is a non invasive diagnostic method with a good sensitivity to the diagnosis of activity in rheumatic carditis, to evaluate the therapeutic results and to define inactivity for surgical cases.