A quick, simple test using a radioactive tracer substance has proven an excellent predictor of whether ischemie ulcers of the leg will heal, a University of Southern California researcher reports.
Ischemic ulcers, common among diabetics and persons with vascular disease, are characterized by a breakdown of tissues, says Michael E. Siegel, MD, director of nuclear medicine at the University of Southern California School of Medicine and at the Los Angeles County/USC Medical Center.
Dr. Siegel and his co-workers have beenstudying the accuracy of two methods to predict whether such ulcers will heal or whether the affected limb will have to be amputated.
They have compared a test using a radioactive' tracer substance called thallium 201 with a test using Doppler. ultrasound. Siegel reports that the thallium 201 test proved significantly superior, successfully predicting the outcome in 86% of the cases studied. The Doppler ultrasound method was accurate in only 62% of the cases.
The Doppler method detects how fast blood travels through major blood vessels only, while the thallium test can detect how much blood actually reaches the tissues. The greater the blood flow to the tissues, the greater the chance the ulcer will heal.
Siegel says that the thallium scan will give physicians an objective criterion in deciding whether to treat ischemie ulcers conservatively or to amputate. He is not suggesting, however, that thallium test results should be the only criterion. He states that the test is valuable because it gives the surgeon or the referring physician some objective data on which to base an assessment of healing potential.
Previously, a physician had to weigh the pros and cons of conservative treatment versus radical treatment on a subjective basis. Conservative treatment of the ulcers often becomes lengthy and expensive, while amputation sometimes may be done prematurely.