Marzio Perri

Scintigraphic imaging of vertebral osteomyelitis with 111in-biotin.

Study Design. Early diagnosis of vertebral infection (hematogenous or postsurgical) is necessary to choose a correct therapy and to minimize dramatic complications. All patients suspected to have vertebral infection underwent radiologic imaging and 111In-Biotin scintigraphy. Objective. Biotin is a growth factor used by many bacteria. The aim of our study is to use 111In-Biotin to diagnose vertebral infections. Summary of Background Data. Magnetic resonance imaging, even if endowed with fairly good sensitivity and specificity, shows some limitations in the study of the onset of pathology and in postsurgical conditions. Conventional scintigraphic imaging, like bone scintigraphy with 99mTc-MDP, 67Ga-citrate scintigraphy, or Positron Emission Tomography with [18F]FDG, are limited by relatively low specificity; the use of Streptavidin/111In-Biotin scintigraphy, based on aspecific uptake of tracer in the site of infection, shows good results in term of sensibility and specificity but the use of heterologous protein might engender immunogenic reactions. Methods. All patients (pts) (n = 110) of the study underwent 111In-biotin scintigraphy 2 hours after intravenous injection of the tracer, 71 pts were suspected to have hematogenous vertebral infection (Group I) and 39 pts were suspected to have postsurgical infection (Group II). The reference for final diagnosis was either bacterial cultures, histopathologic analysis, and/or clinical/imaging follow-up for at least 1 year. Results. 111In-biotin scintigraphy showed a sensitivity of 84% and specificity of 98% in Group I and a sensitivity of 100% and specificity of 84% in Group II. Conclusion. Our results showed that 111In-Biotin scintigraphy possess high diagnostic accuracy. This technique is easy to perform and requires short imaging time-point after intravenous tracer injection. Moreover if 111In-Biotin uptake is due only to high proliferation rate of bacteria presents in site of infection, it will be further investigated to discriminate definitely bacterial from sterile inflammation.

Adrenal Masses in Patients With Cancer: PET/CT Characterization With Combined CT Histogram and Standardized Uptake Value PET Analysis

OBJECTIVE Our purpose was to determine the diagnostic performance of 18F-FDG PET/CT for characterizing adrenal masses in patients with cancer, combining standardized uptake value (SUV) and CT histogram analysis. MATERIALS AND METHODS A total of 117 adrenal masses in 93 patients with cancer (61 men and 32 women; mean [± SD] age, 67.2 ± 10.3 years; range, 38-84 years) were evaluated with FDG PET/CT. Of the 117 lesions, 42 were malignant according to histopathologic analysis or size change, whereas 75 were benign on the basis of stability for 6 months. Size, mean attenuation value, percentage of negative pixels at CT histogram analysis, maximum SUV (SUV(max)), and average SUV were calculated for each adrenal lesion. Moreover, FDG adrenal uptake was compared with radioactivity of the aorta, liver, and spleen by calculating the SUV ratios of adrenal lesion to aorta, adrenal lesion to liver, and adrenal lesion to spleen. PET/CT value was assessed by using independent t tests and receiving operating characteristic (ROC) analysis. RESULTS There was a statistically significant difference in size, attenuation value, percentage of negative pixels, and SUV between benign and malignant masses. All malignant lesions showed FDG activity higher than that in liver, spleen, and aorta, with SUV(max) greater than 2.8 in all cases, whereas with the CT histogram analysis, all lesions with a percentage of negative pixels higher than 10% were benign. Combined SUV and CT histogram analysis yielded 100% sensitivity, 97.3% specificity, 95.7% positive predictive value, and 100% negative predictive value. At ROC analysis, combined SUV and CT histogram analysis (area under the ROC curve [AUC], 0.996) was more accurate than simple SUV(max) analysis (AUC, 0.961) and the combination of SUV(max) and attenuation value (AUC, 0.987). CONCLUSION The combination of SUV and CT histogram analysis allowed us to significantly improve the PET/CT diagnostic accuracy for characterizing adrenal lesions, leading to a significant reduction in the number of false-positive cases.

Clinical impact of SPECT/CT with In-111 biotin on the management of patients with suspected spine infection.

Purpose: Early identification and localization of spine infection is necessary for adequate therapeutic strategy. To localize the precise site of infection we evaluated In-111 Biotin SPECT/CT versus planar and SPECT imaging. Methods: Seventy-two consecutive patients were enrolled and underwent SPECT/CT and planar imaging 2 to 4 hours post i.v. injection of In-111 Biotin. Final diagnosis was based on bacterial cultures and/or clinical/imaging follow-up for at least 1 year. We evaluated the diagnostic performance of planar, SPECT, and SPECT/CT In-111 Biotin scintigraphy. Results: In-111 Biotin SPECT/CT and SPECT showed similar values of sensitivity (93.5% vs. 92.1%) and the same specificity (92.3%), planar imaging showed 80.4% of sensitivity and 69.2% of specificity. In 16 patients SPECT/CT correctly localized the infection site (bone, soft tissue, or both bone and soft tissue). Conclusions: SPECT/CT enhances the impact of In-111 Biotin scintigraphy on the clinical management of patients, allowing the exact site of infection to be localized to select the appropriate therapy.

Current role of 111In-DTPA-octreotide scintigraphy in diagnosis of thymic masses.

AIMS AND BACKGROUND Thymic tumors (thymomas and thymic carcinomas) represent 50% of all mediastinal tumors. Thymomas usually express high levels of somatostatin receptors, which enable in vivo imaging with 111In-DTPA-octreotide (OctreoScan®). The aim of this study was to further investigate the role of radionuclide techniques in the diagnosis, staging and follow-up of these tumors. METHODS Eight patients (5 women, 3 men, age range 35-79 years; mean ± SD 56.1 ± 15.8 years) entered the study. In 4 patients, myasthenia gravis was the presenting symptom. 111In-DTPA-octreotide scan was performed within 3 weeks after contrast enhanced CT and/or MRI. Planar and tomographic images were acquired within 24 hours of the injection of 111 MBq OctreoScan. The scintigraphic results were defined in correlation with the histological findings. RESULTS Histology revealed thymoma in 3 patients, thymic carcinoma in 1, insular carcinoma of presumably thymic origin in 1, thymic carcinoid in 1, and thymic hyperplasia in 2 patients. Two thymomas were at stage I, 1 thymoma and 1 thymic carcinoma at stage II, 1 insular carcinoma of presumably thymic origin at stage IV, and 1 thymic carcinoid at stage IV. OctreoScan consistently accumulated in primary and/or metastatic sites of thymic tumors while no radiotracer uptake was detected in the 2 patients with benign thymic hyperplasia. In 1 patient with a very large mediastinal mass (13 cm in largest diameter) and multiple metastatic deposits in the lungs, OctreoScan scintigraphy showed a large area of pathological uptake in the anterior mediastinum and a small area of focal uptake in the cervical-dorsal region of the right lung corresponding to a lymph node expressing somatostatin receptors. CONCLUSIONS OctreoScan is avidly taken up by thymic tumors, enabling the diagnosis of these tumors and a better evaluation of their extension. It does not accumulate in thymic hyperplasia, thus allowing the differential diagnosis between these 2 pathological conditions. In patients affected by myasthenia gravis, OctreoScan scintigraphy can play an important role in characterizing thymic masses.

Standardization of MRI and Scintigraphic Scores for Assessing the Severity of Bone Marrow Involvement in Adult Patients With Type 1 Gaucher Disease

OBJECTIVE MRI and (99m)Tc-sestamibi scintigraphy are used to estimate bone marrow infiltration in patients with Gaucher disease (GD), but comparison of data obtained at different institutions is difficult because different scores are employed for semiquantitative assessment. We developed normalized scores for comparing data both within a single method (MRI) and between different methods (MRI versus scintigraphy). MATERIALS AND METHODS We evaluated 51 patients with type 1 GD (26 women, 25 men; mean age ± SD, 36.3 ± 10.9 years old). T1- and T2-weighted turbo spin-echo sequences at 1.5 T served to derive the bone marrow burden score (0-16), the vertebra-disk ratio (VDR), the Terk score (0-3), and the Spanish-MRI score (S-MRI, 0-24). Scintigraphy was scored between 0 and 8. Each score was normalized into four categories: 0 = normal, 1 = mild, 2 = intermediate, 3 = severe involvement. Interobserver and intraobserver agreements were evaluated by kappa statistics; nonparametric statistics with Bonferroni correction assessed correlations among the various original and normalized scores. RESULTS Interobserver agreement was excellent for the original scores (κ = 0.730-0.843) and even more so for the normalized scores (κ = 0.775-0.940). Intraobserver agreement kappa values ranged from 0.753 to 0.937 for the original scores and 0.851 to 1.000 for the normalized scores. Highly significant correlations were found among the various original scores (r = 0.42-0.86, p values between 0.0296 and < 0.0001), except for VDR versus S-MRI and Terk. Normalization generally induced marginal reductions in statistical significance, whereas S-MRI versus VDR reached statistical significance with the normalized scores. CONCLUSION Our data indicate no significant loss of statistical information is caused by the normalization we employed. Our approach therefore facilitates comparison of different scores obtained in different institutions with different imaging modalities.

Where it all began: the heritage of radioimmunoguided surgery

In the mid-1970s, crucial advances in immunology led to widespread fascination with the development of radiolabeled antibodies for immunoscintigraphy of primary or secondary tumors. The availability of these radiolabeled tumor-seeking agents constituted the first step toward radioimmunoguided surgery, as pioneered by Martin et al. (1),(2) in patients with colorectal cancer. This chapter provides an overview of the evolution of the radioimmunoguided surgery system, explains its main technical aspects, and outlines its clinical applications.