Radiolabeled Complex of Antimicrobial Peptides UBI29-41 and UBI18-35 Labeled with 99mTc for Differential Diagnosis of Bone Infection of the Limbs.

We studied an original radiolabeled complex of antimicrobial peptides UBI29-41 and UBI18-35, ubiquicidin derivatives, for distinguishing between bacterial and aseptic inflammation. For radiolabeling of the peptides with technetium-99m, a bifunctional chelating agent succinimide-1-yl 6-(bis(pyridin-2-ylmethyl)amino)hexanoate was used. The obtained complexes 99mТс-DPAH-UBI29-41 and 99mТс-DPAH-UBI18-35 had radiolabeling yield >80% and radiochemical purity >96%. Accumulation of the complexes in the focus of bacterial inflammation in bone structures and the absence of this complex in the site of aseptic inflammation was confirmed in a rat model of traumatic osteomyelitis by single-photon emission computed tomography.

[Possibilities of a software-based hybrid single photon emission computed tomography/magnetic resonance imaging in the diagnosis of complicated diabetic foot syndrome].

OBJECTIVE: To give the results of a software-based hybrid single photon emission computed tomography/magnetic resonance imaging (SPECT/MRI) in detecting osteomyelitis (OM) in patients with diabetic foot syndrome (DFS). MATERIAL AND METHODS: Seventy-six patients (35 men and 41 women) (mean age, 59.4 +/- 7.1 years) with type 1 and 2 diabetes mellitus and suspected OM were examined. The investigation enrolled patients with neuropathic (n = 25), ischemic (n = 13), and mixed (n = 38) DFS. All the patients underwent (99m)Tc-HMPAO/ (99m)Tc-technefit labeled leukocyte scintigraphy; magnetic resonance imaging was performed in 30 patients. The results were combined using RView 9.06 software (Colin Studholme). RESULTS: Labeled leukocyte SPECT to Diagnose OM yielded 255 true positive (TP), 38 true negative (TN), 12 false negative (FP), and 1 false negative (FN) results. The accuracy of the technique was 82.9%. The FP results were due to the low resolution of the technique and to the small sizes of the object under study. One FN result was detected in a patient with ischemic DFS because of reduced blood flow. MRI to identify OM in patients with DFS provided 20 TP, 16 TN, 4 FP, and 2 FN results. Its diagnostic accuracy was 85.7%. The relative low specificity of MRI was associated with the presence of FP results due to the complexity of differential diagnosis of bone marrow edema and inflammatory infiltration. Assessing 42 hybrid SPECT/MR-images revealed 21 TP, 17 TN, 3 FP, and I FN results. The diagnostic accuracy was equal to 95.9%. CONCLUSION: Thus, comparing MRI (90.9% sensitivity and 80.0% specificity), labeled leukocyte scintigraphy (96.2% sensitivity and 76.0% specificity), and hybrid SPECT/MRI (95.5% sensitivity and 85.0% specificity) showed the high diagnostic efficiency of the latter.

[Role of magnetic resonance imaging in the study of patients with diabetic foot syndrome].

OBJECTIVE: To give the results of magnetic resonance imaging (MRI) in patients with complicated diabetic foot syndrome (DFS) to rule out or identify osteomyelitis. MATERIAL AND METHODS: Twenty-seven (14 women and 13 men; mean age 60 ± 12.2 years) with type 1 and 2 diabetes mellitus and suspected osteomyelitis that had developed in the presence of DFS were examined. Ankle joint and foot MRI was carried out in T1-weighted MR image, T2-weighed MRI image, and FSat sequences. The soft tissue, tendoligamentous apparatus, and bones were evaluated. The results of MRI were compared with the data of a clinical follow-up study and surgery, followed by morphological examination. The diagnosis of osteomyelitis was validly established in 7 cases; this disease was absent in 20 patients. RESULTS: MRI showed the highest sensitivity for bone marrow edema (100%), soft tissue swelling (85.7%), and their concurrence (85.7%) and the highest specificity for an extensive wound defect or fistula attached to the bone (100%) and bone marrow edema concurrent with tenosynovitis (90%). With a sensitivity of 14.3% and a specificity of 10%, MRI was of less informative value in assessing bone destruction. It was characterized by moderate sensitivity and moderate specificity for soft tissue destruction (57.1 and 42.9%, respectively) and tenosynovitis (55 and 50%, respectively). CONCLUSION: Osteomyelitis MRI demonstrated a polymorphic pattern with different diagnostic efficiency for individual symptoms.