[99mTc-tetrofosmin exercise leg perfusion scintigraphy in arteriosclerosis obliterans (ASO)--assessment of leg ischemia using two phase data acquisition].
Twenty-one patients with arteriosclerosis obliterans (ASO) were studied with 99mTc-tetrofosmin exercise leg perfusion scintigraphy using the delayed administration method. In this method, tracer was injected 4 minutes after termination of symptom-limited repetitive climbing of a stair to validate prolonged vasodilatation in an ischemic lower limb after exercise. Visual and quantitative analyses were performed to evaluate a diseased leg using dynamic and static images. On a posterior whole body image, all cases except one showed decreased foot uptake in the affected side (affected normal ratio; ANR = 0.82 +/- 0.14). On dynamic images, 9 cases showed transient hyper-accumulation (blush phenomenon) only in the thigh of the affected side suggesting that this valuable finding may be a useful diagnostic sign to distinguish a diseased leg. Sensitivity and positive predictive value were 71.4% and 93.8% to detect a diseased leg based on more than one finding of non-visualization of ilio-femoral artery, muscle-soft tissue blush, and early venous return in a dynamic study. Moreover, a low uptake of ANR of below 0.90 in the foot in the static study gave an improved sensitivity of 85.7%. The transit time of the diseased legs (12.0 +/- 3.1 sec.) which was determined as the interval between the time of arterial and venous peak counts was significantly shorter than that of normal legs (17.3 +/- 4.5 sec.; p < 0.0001, paired t-test). The cases with blush phenomenon showed significantly higher thigh ANR (1.04 +/- 0.11) than those without (0.94 +/- 0.08; p < 0.05, unpaired t-test). These results could reflect prolongation of a hypervascular state after exercise in a diseased leg which sometimes induced blush phenomenon at arterial phase and high leg uptake at static phase. This scintigraphy is useful for the detection of a diseased leg as well as for grasping changes of vascular regulation after stress in patients with ASO.
Department of Radiology, Nippon Medical School.
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Kijima
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Kumita
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Cho
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Kumazaki
D000368:Aged; D000369:Aged, 80 and over; D001162:Arteriosclerosis Obliterans / Q000000981:diagnostic imaging*; D005080:Exercise Test; D005260:Female; D006801:Humans; D007511:Ischemia / Q000000981:diagnostic imaging; D007866:Leg / Q000098:blood supply* / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin