The Diagnostic Value of 99mTc-IgG Scintigraphy in the Diabetic Foot and Comparison with 99mTc-MDP Scintigraphy

Abstract

Diabetic foot infection is the most common etiology of nontraumatic amputation of the lower extremities, and early diagnosis is of great importance in its management. The aim of this prospective study was to evaluate the strength of 99m TcIgG scintigraphy in diagnosis of osteomyelitis of the diabetic foot and to compare 99m Tc-IgG scintigraphy with 99m Tc-methylene diphosphonate (MDP) scintigraphy. Methods: A prospective university hospital-based study was performed over 24 mo. Eighteen patients with type II diabetes and foot ulcers (15 men and 3 women; age range, 45-80 y) were referred for imaging because of clinically suspected osteomyelitis. Early (5-h) and late (24-h) 99m Tc-IgG scanning and 3-phase skeletal scintigraphy were completed for all patients at a 3-to 4-d interval.Regions of interest over the involved bony sites and the contralateral normal sites were drawn, and the abnormal-to-normal ratios were acquired for both 99m Tc-IgG and 99m Tc-MDP studies. Results: From a total of 23 lesions, we observed 10 sites of osteomyelitis, 10 sites of cellulitis, and 3 sites of aseptic inflammation confirmed by MRI, clinical presentation, histopathologic examination, and follow-up evaluation as a gold standard. Both 99m Tc-IgG and 99m Tc-MDP scanning showed excellent sensitivity for diagnosis of osteomyelitis, but the specificity was significantly lower (69.2% and 53.8%, respectively). Sensitivity, specificity, and accuracy in the diagnosis of osteomyelitis were, respectively, 100%, 53.8%, 73.9% for 99m Tc-MDP scanning; 100%, 69.2%, 82.6% for 5-h 99m Tc-IgG scanning; and 60%, 76.9%, 69.5% for 24-h 99m Tc-IgG scanning. There was no significant difference between the semiquantitative indices of 5-h and 24-h 99m Tc-IgG scanning for inflammation, cellulitis, and osteomyelitis. Conclusion: Although both 99m Tc-IgG and 99m Tc-MDP scintigraphy have high sensitivity for the diagnosis of osteomyelitis, the specificity of these studies is poor. For 99m Tc-IgG scintigraphy, 5-h images appear to be adequate, and there is little benefit to performing additional imaging at 24 h. Peri pheral neuropathy and metabolic and vascular disorders are important contributing factors leading to infection of obscured wounds in diabetic patients (1,2). When there is evidence of osteomyelitis, invasive procedures are needed to avoid amputation (3). Radiographic evaluation is not sensitive for the development of osteomyelitis, whereas labeled leukocyte imaging followed by bone marrow scintigraphy, although both sensitive and specific, is labor-intensive and limited by the risks associated with handling blood products (4). 111 In-IgG and 99m Tc-methylene diphosphonate (MDP) scintigraphy can be helpful for the diagnosis of inflammation and infection (5-11).The aim of this prospective study was to assess the role of 99m Tc-IgG scintigraphy in the diagnosis of osteomyelitis in the diabetic foot and to compare 99m Tc-IgG scintigraphy with 99m Tc-MDP scintigraphy. In addition to qualitatively assessing the 99m Tc-MDP and 99m Tc-IgG studies, we have...

Scintigraphic Evaluation of the Stump Region After Extremity Amputation and the Effect of Scintigraphy on Treatment

“…Bone scintigraphy has over 90% sensitivity and 70-90% specificity in acute hematogenous osteomyelitis [ 21 ]. The sensitivity and specificity of MRI are close to each other [ 15 ]. The sensitivity of MRI in osteomyelitis of the peripheral skeleton is not different from leukocyte scintigraphy of combined bone and gallium scintigraphy.…”

“…Increased activity accumulation that is seen in the late phase is not specific to infection and may be seen in tumors, fracture, and arthropathy. For this reason, gallium-67 and Tc-99m human immune globulin, or indium-111-labeled leukocytes are often used as complementary techniques [ 15 , 16 ]. Gallium-67 scintigraphy has 83% sensitivity and 79% specificity; indium-111-labeled leukocyte scintigraphy has 83-100% sensitivity and 90% specificity [ 4 , 16 ].…”

99mTc-IgG-Lung Scintigraphy in the Assessment of Pulmonary Involvement in Interstitial Lung Disease and Its Comparison With Pulmonary Function Tests and High-Resolution Computed Tomography: A Preliminary Study

“…The 99mTc-IgG is a radiotracer that has been applied in studies of focal infection and inflammation in immune disorders such as rheumatoid arthritis (RA), Sjogren’s syndrome and inflammatory bowel disease ( 7 , 9 , 14 , 15 ). Numerous uptake mechanisms have been illustrated to contribute to 99mTc-IgG accumulation ( 7 , 15 ). Primarily, 99mTc-IgG uptake thought to be due to increased vascularity and vascular permeability at the site of inflammation.…”

“…The scans, together with plain chest radiographs, were assessed by a pulmonary radiologist. The presence or absence of patchy ground glass pattern, reticular pattern, emphysema, honeycombing, airways distortion, and bronchial wall thickening scans were recorded ( 7 ). The parenchymal abnormalities identified on HRCT were coded, and a score was defined according to Goldin et al ( 11 ).…”

“…In this respect, a number of radiopharmaceuticals such as 67 Ga-citrate and 111 In-octreotide in the lungs and diminished clearance time of 99mTc-DTPA aerosol for scintigraphic recognition of ILD have been suggested ( 7 ), yet an optimal agent with high concordance with HRCT and PFTs is still missing ( 8 ).…”