Thallium 201 Muscle Scintigraphy: Application to the Management of Patients with Arterial Occlusive Disease

Abstract

Skull (S), thigh (T), and calf (C) scintigraphies were performed by using 2 mCi thallium 201 IV in 30 patients suffering from stages II, III, and IV arterial occlusive disease (Fontaine's classification). Two indexes were calculated: P=T/C-C/S (T/C and C/S were the absolute values of radioactivity ratios measured before medical treatment) and R=Δ(C/S)-Δ(T/C) (where Δ expressed the relative variation of the ratios measured after treatment and compared with initial values). Angiography was performed on all patients prior to treatment, and the results were quantified as 1 in the case of obliteration and 0.5 in case of stenosis of major arterial axes. Clinical improvement was demonstrated by a 100% increase in walking distance for stage II disease, abolition of pain at rest for stage III disease, and reepithelialization of trophic lesions for stage IV disease. Paraclinical effectiveness was evaluated by measuring ankle systolic pressure (SP) and index (SI) before and after treatment.

The correlation observed between the values of P and angiography results was p < 0.025 (Student t-test). The mean of P (measured before treatment) was 1.75 for the improved patients and 0.56 for the others (p < 0.005). After treatment, R was + 58% for improved patients versus —13% in those in whom the treatment was inefficient (p < 0.025).

P expresses the microcirculatory effects of arterial lesions detected by angiography. It is a prognostic index: satisfactory proximal perfusion (high T/C), associated with lesions that are essentially peripheral (low C/S), predicting a positive effect of medical treatment. R measures the increase in peripheral circulation (increase in C/S) at the expense of the proximal region (decrease in T/C) and quantifies the results of treatment. SI gives the same information, but the correlation is less precise.