High resolution mini-gammacamera and 99mTc [HMPAO] - leukocytes for diagnosis of infection and radioguided surgery in diabetic foot.

Discovery of osteitis may be delayed because of late appearance of X-ray signs in patients with diabetic foot. Scintigraphy with labelled leukocytes is able to detect flogosis but often misses bone involvement, due to inadequate resolution of Anger camera, the commonest detector used in nuclear medicine. Radioguided surgery and biopsy with high resolution scintigraphy (HRS) started to be studied since 2000: although this method had never been tested for planning and guiding diabetic foot surgery, in our opinion it can help early diagnosis and surgical treatment of diabetic foot. Five patients with diabetic foot and suspected infection were studied with standard 99mTc [HMPAO]-leukocyte scan. In the same patients 2 mm spatial resolution HRS was performed 24 hours after administration of labelled WBC, using our inch2 field-of-view portable mini-gammacamera. Operations were done just after the 24h scan and were guided with the portable high resolution device in the four patients who showed positive scan. Scintigraphy with Anger camera and HRS were positive in four patients. HRS showed a bar-shaped radioactivity corresponding to small phalanges, close to the main inter-digital hot spot. The presence of osteitis on phalanges that had been shown by HRS was confirmed at surgery, that was successfully driven with the high resolution mini-camera. In conclusion HRS is able to diagnose early osteitis of diabetic foot and to guide diabetic foot surgery.