technetium-tc-99m-medronate and Diabetic-Angiopathies

Early and accurate diagnosis of infection or neuropathy of the diabetic foot is the key to successful management. Angiopathy leads to ischemia which, in combination with peripheral neuropathy, predisposes to pedal skin ulceration, the precursor of osteomyelitis. Chronic hyperglycemia promotes production of glycosylated end products which accumulate on endothelial proteins, causing ischemia of the vasa nervorum. When combined with axonal degeneration of the sensory nerves, the result is hypertrophic neuroarthropathy. Should the sympathetic nerve fibers also be damaged, the resultant loss of vasoconstrictive impulses leads to hyperemia and atrophic neuroarthropathy. Plain radiography, although less sensitive than radionuclide, magnetic resonance (MR), and computed tomographic examinations, should be the initial procedure for imaging suspected osteomyelitis in the diabetic patient. If the radiographs are normal but the clinical suspicion of osteomyelitis is strong, a three-phase 99mTc-MDP scan or MR imaging is recommended. An equivocal 99mTc-MDP scan should be followed by MR imaging. To exclude osteomyelitis at a site of neuroarthropathy, a 111In white blood cell scan is preferable. To obtain a specimen of bone for bacteriological studies, percutaneous core biopsy is the procedure of choice, with the entrance of the needle well beyond the edge of the subjacent ulcer.

Topics: Biopsy, Needle; Diabetic Angiopathies; Diabetic Foot; Diabetic Neuropathies; Diagnostic Imaging; Female; Foot Diseases; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Osteomyelitis; Radionuclide Imaging; Technetium Tc 99m Medronate; Tomography, X-Ray Computed

The study was conducted in order to assess the prevalence of osteomyelitis and the predictive value of radiographic (xR) and combined Tc 99-bone and leukocyte scanning (CS) findings in diabetic foot ulcers that met criteria for hospital admission (FUH). Out of 150 episodes of ulceration managed in an outpatient basis, 33 (in 28 NIDDM patients) requiring admission were evaluated. In all cases plain xR and CS were carried out. Seventeen episodes (51.5%) had a good outcome (healed or improving, at the time of the last follow up). Osteomyelitis was found in 21 episodes and 14 (66.6%) of them required an amputation. In 13 cases where xR showed characteristic radiologic changes of osteomyelitis (11 of them had a positive CS) 11 (84.6%) underwent an amputation. However, when osteomyelitis was diagnosed only by a positive CS, only 3/8 (37.5%) required a toe amputation. Severe peripheral vasculopathy was present in 44% of cases who required amputation and only in 17.6% of those who did not. We conclude that in FU underlying osteomyelitis is frequent and associated to a higher amputation rate than when no bone infection is identified (66.6 vs 17%), even when corrected for vascular status (OR 11, CI 95% 1.65-74.2), with a worse outcome when xR changes are already present.

Topics: Aged; Amputation, Surgical; Angiography; Bone and Bones; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diabetic Foot; Female; Humans; Leukocytes; Male; Middle Aged; Osteomyelitis; Prevalence; Radionuclide Imaging; Sensitivity and Specificity; Spain; Technetium Tc 99m Medronate; Toes; Wound Healing

In diabetic gangrene, concomitant osteopathy and soft-tissue infection often render laboratory and roentgenographic signs unreliable as indicators of osteomyelitis. In this situation, scintigraphic methods can be helpful.. Relying on the long-term clinical course as the final indicator of presence or absence of osteomyelitis, we prospectively compared in 31 patients three-phase bone scintigraphy with either indium-labeled autologous granulocytes (n = 20) or 123I-labeled antibodies against granulocytes (n = 11).. Three-phase bone scintigraphy and imaging with indium-labeled autologous granulocytes yielded sensitivities and specificities of 95 and 70% for bone scintigraphy and 77 and 100% for granulocyte scintigraphy, respectively. One patient with severe angiopathy and proved osteomyelitis had a negative bone scintigraphy but a positive scintigraphy with labeled antibodies against granulocytes. One patient with aseptic bone necrosis presented with a formally false positive result with both methods.. In contrast to former retrospective studies, three-phase bone scintigraphy compares very well with granulocyte scintigraphy. The care of most patients can be managed with clinical data and this widely available scintigraphic method.

Topics: Bone and Bones; Diabetes Complications; Diabetic Angiopathies; Diagnosis, Differential; Female; Gangrene; Granulocytes; Humans; Indium Radioisotopes; Iodine Radioisotopes; Male; Middle Aged; Osteomyelitis; Prospective Studies; Technetium Tc 99m Medronate; Tomography, Emission-Computed

The delayed images of the four-phase 99mTc phosphonate bone scan are compared with the delayed images of the three-phase study in patients with diabetes mellitus and/or peripheral vascular disease and suspected osteomyelitis. Three-phase bone imaging includes an immediate postinjection radionuclide angiogram, a blood-pool image, and delayed static images to 7 hr. The four-phase study adds a 24-hr static image. The scan is positive for osteomyelitis if images show progressively increasing lesion to background activity ratios over time. The results of analyzing 21 three- and four-phase bone scans in 17 patients were correlated with clinical course, cultures, and/or x-rays, gallium scans, and CT scans. The accuracy of four-phase bone imaging for diagnosing osteomyelitis was 85%; for three phase, 80%. Sensitivity for four phase was 80%; specificity was 87%. Sensitivity for three phase was 100%; specificity was 73%. Since overall accuracy of the four-phase study is slightly better than three phase, in these patients with diabetes mellitus and/or peripheral vascular disease, the addition of a 24-hr image, creating a four-phase bone scan, is recommended.

Topics: Diabetic Angiopathies; Diphosphonates; Humans; Leg; Leg Ulcer; Osteomyelitis; Radionuclide Imaging; Technetium; Technetium Tc 99m Medronate; Time Factors; Venous Insufficiency