Whole-body Tl-201 scintigraphy can detect exercise lower limb perfusion abnormalities in asymptomatic diabetic patients with normal Doppler pressure indices

Significant lower limb arterial obstruction is usually detected by Doppler ankle-brachial pressure index (ABPI) measurement. However, ABPI is non-cont ributory in cases of diabetic medial sclerosis or calcifications and is uns uitable for the detection of small vessel involvement. Thallium-201, a perf usion agent, is frequently used for the investigation of coronary artery di sease, and whole-body Tl-201 scintigraphy (WBS) has also been reported to b e useful in the assessment of peripheral artery disease (PAD). Thus, we eva luated the clinical feasibility of simultaneous myocardial and lower limb p erfusion assessment. WBS was performed after treadmill exercise and myocard ial scintigraphy, and again 4 h later. Calf Tl-201 fractional activities (p ercentage of whole-body Tl-201 uptake) were calculated. We determined a thr eshold value of normal post-exercise calf Tl-201 uptake (mean of the Tl-201 fractional uptakes minus 2 SD) in a control group of nine healthy voluntee rs. We checked its accuracy in a pilot group of 25 diabetic patients with p roven PAD. This method permitted the detection of lower limb perfusion abno rmalities in 38% of 47 asymptomatic diabetic patients with no evidence of P AD. In conclusion, for asymptomatic diabetic patients, whole-body Tl-201 sc intigraphy after a treadmill test seems an efficient method of showing lowe r limb perfusion abnormalities not detected by ABPI measurement. It allows the evaluation of vascular status with no additional inconvenience for pati ents when performed after myocardial scintigraphy. ((C) 2001 Lippincott Wil liams & Wilkins).