Assessment of peripheral arterial vascular disease with radionuclide techniques

Various radioisotopic imaging techniques for noninvasive detection of vesse l stenosis and for functional investigation of reduced blood flow and follo w-up have been developed during the last decade in peripheral vascular dise ase (PVD), with the aim of replacing invasive techniques and complementing standardized methods. Radionuclide assessment of PVD is divided into 2 majo r groups: imaging of perfusion and metabolic investigations. The measuremen t of arterial blood flow and muscle perfusion is intended to show the morph ology, to evaluate the functional consequences of PVD, and to quantify the latter. The application of radiolabeled tracers was developed as a noninvas ive alternative to angiography in morphologic imaging. Treadmill testing ha s been used to assess the functional effects of reduced blood flow in PVD w here the onset of pain indicates the stage of disease, but the results can be confused by other symptoms. Scintigraphic measurement of muscle perfusio n should detect insufficient nutritional blood flow in peripheral muscle an d thus have a higher specificity for PVD than treadmill testing alone. Alth ough there are very promising theoretical and experimental data in animals, the clinical use of radionuclide investigations is limited by different te chnical problems, such as methodologic differentiation between skin and mus cle perfusion, the lack of controlled and prospective studies, and incomple te correlation with other standardized routine techniques. Among the great number of radioisotopic metabolic imaging techniques, only radiolabeled pla telets and lipoproteins, to some extent, have shown a limited potential cli nical use. Some other approaches seem to have a high potential from a theor etical point of view. They are limited, however, by a great number of probl ems. Correlation with sonographic or magnetic resonance imaging (MRI) findi ngs may identify a potential metabolic value. Correlation with angiography reflecting the extent of the disease makes no sense. So far with PVD, neith er radioisotopic perfusion studies nor metabolic imaging techniques are abl e to achieve a level of routine application or wider meaningful interpretat ion of the clinical condition of a specific patient. Competing techniques a re easier to perform, less expensive, faster, more widely available, and do not carry the radiation burden. Positron emission tomography is still in i ts early stages of application, with great theoretical potential but at a h igh price. A great deal of work is still required to transform in vitro and experimental experience into more meaningful routine radioisotopic investi gations in patients with PVD. Copyright (C) 2001 by W.B. Saunders Company.