[18F-FDG positron emission tomography in the diagnosis and staging of marginal zone non-Hodgkin lymphomas].

OBJECTIVE: To investigate the diagnostic value of 18F-FDG positron emission tomography (PET) in the diagnosis and staging of marginal zone non-Hodgkin lymphomas (NHLs). MATERIAL AND METHODS: Twenty-four patients with new-onset NHLs were examined. Extranodal MALT lymphoma, splenic marginal zone lymphoma (MZL), and nodal MZL lymphoma were diagnosed in 18, 3, and 3 patients, respectively. 18F-FDG PET was carried out by the standard protocol via whole-body examination, by estimating the standardized tracer uptake value (SUV(max)) in the abnormal foci. RESULTS: Most (83.3%) of the examinees were found to have abnormal tracer hyperfixation foci. The mean SUV(max) was 5.05 ± 0.9. There was no correlation between SUV(max) in the tumor foci and their metabolic sizes (r = 0.1; p = 0.7). No significant differences between the mean SUV(max) were found in patients with different histological types of MZL (p > 0.05). Disease staging by PET and other diagnostic methods yielded contradictory results in three patients. The final analysis suggested that the stage had been correctly determined in all the 3 patients from PET findings. CONCLUSION: The results of 18F-FDG PET suggest that it is of high iagnostic value in imag-ng marginal zone NHLs. The major advantage of PET is that it can accu-ately stage the disease, which can provide a ra-ionale for optimal treat-ent policy.

[Differential diagnosis of brain gliomas by positron emission tomography using various radiopharmaceuticals].

OBJECTIVE: To comparatively study the diagnostic capabilities of positron emission tomography (PET) with various tumorotropic radiopharmaceuticals (TRPs) in detecting malignant brain gliomas (BG) and estimating their degree. MATERIAL AND METHODS: One hundred and fourteen patients, including 47 with histologically verified glioblastoma multiforme (GBM), 27 with anaplastic astrocytoma (AA), 23 with benign astrocytoma (BA), and 17 with postoperative cysts, were examined. PET was performed using TRPs: 18F-fluorodesoxyglucose (18F-FDG), 11C-sodium butyrate (11C-SB), 11C-L-methionine (11C-MET), and 11C-choline (11C-COL). RESULTS: Malignant gliomas (GBM and AA) were clearly visualized by PET using 11C-MET, 11C-CHOL, and 11C-SB. 18F-FDG PET visualization of tumors was difficult because of increased RP accumulation in the cerebral cortex. WHO grades II-III gliomas were completely visualized by 11C-MET PET. Only some tumors were clearly displayed by PET with 11C-CHOL and 11C-SB. The accumulation indices (AI) obtained by 11C-CHOL PET in patients with malignant gliomas were, on average, 4.0- and 5.5-fold higher than those by 11C-MET and 11C-SB PET, respectively. Significant differences (p < 0.001) in AI obtained by "C-CHOL ("C-CHOL-AI) PET were first established between the patients with GBM (WHO grade IV) and those with AA (WHO grade III). CONCLUSION: 11C-CHOL PET is the most sensitive method to identify gliomas and estimate their grade. The advantage of 11C-MET PET is the possible imaging of the entire volume of viable tumor tissue.

[Prognostic value of 18F-FDG positron emission tomography in the early evaluation of the efficiency of treatment in patients with non-Hodgkin lymphomas].

OBJECTIVE: To define the role of 18F-FDG positron emission tomography (PET) performed after 2-3 chemotherapy cycles in the prediction of disease prognosis and to identify a group of patients requiring more intensive treatment. MATERIAL AND METHODS: Seventy-one patients with non-Hodgkin lymphoma of different histological types were examined. PET was carried out at different stages of diagnosis and primary treatment in the patients. RESULTS: The examinations made after 2-3 polychemotherapy (PCT) cycles indicated that 36 (50.7%) patients continued to have signs of metabolic activity of lymphoproliferative disease (a PET-positive group) and 35 (49.3%) patients were found to have no abnormal tracer accumulation foci (a PET-negative group). Twenty-nine (82.9%) patients from the PET-negative group continued to remain in complete remission throughout the follow-up (the median follow-up was 405 days). At late stages, 6 (17.1%) patients were identified to have abnormal tracer hyperfixation foci that were indicative of disease recurrence. Only 8 patients from the PET-positive group were observed to show a complete metabolic response to treatment at the end of first-line PCT. The metabolic activity of the disease was maintained in the remaining patients. The results of PET conducted at the late stages of the follow-up indicated that metabolically active tumor foci continued to be visualized in 20 (55.6%) patients and further treatment resulted in complete remission in 16 (44.4%) patients. CONCLUSION: PET findings could predict the further course of the disease and differentiate more intensive treatment-requiring patients at the early stages of chemotherapy.

[First experience of using positron emission tomography with 11C-choline in prostate cancer (PC)].

Introduction into clinical practice of combined positron emission technology and computer tomography (PET/CT) allows in one study to identify structural and functional abnormalities. The study involves 32 patients who underwent PET/CT with "C-choline, including 5 patients with prostate cancer (PC), 3--with chronic prostatitis and 24--with biochemical PC recurrence. PET/CT with 11C-choline has a high diagnostic efficacy in detection of local recurrence and PC metastases in patients with biochemical PC recurrence. The results of visual analysis do not permit to distinguish PC from benign prostate diseases.

[Biodistribution of the recombinant heat shock protein rhHsp70 in intracranial C6 glioma models in Wistar rats and subcutaneos B16/F10 melanoma in C57BL/6 mice].

For the first time, the biodistribution of recombinant heat shock protein in rhHsp70 rats with grafted intracranial C6 glioma was evaluated. It was assessed using the fluorescent antibody accumulation chaperone rhHsp70 conjugated with fluorochrome Alexa Fluor 555 in tumor cells by intratumoral or intravenous administration. Assessment of the distribution and accumulation of labeled protein was carried out on the model of subcutaneous B16/F10 melanoma in C57BL/6 mice with the use of single-photon emission computer tomography. After 60 minutes after intravenous administration rhHsp70-I123 (20 MBq, 5 mg chaperone) accumulation of the drug mainly in the liver and tumor tissue was showed. The coefficient of the differential accumulation of the labeled protein KDN(tumor/background) was 3.14. It was turned out that comparing the level of fixation of rhHsp70-I123 in the liver and the tumor KDN(tumor/ liver) = 0.76. After 24 hours from the time of injection of rhHsp70-I123 it was observed increase the level of fixation of the labeled protein in the liver and melanoma: KDN(tumor/background) = 3.43; KDN(tumor/liver = 0.78.

[The application of nuclear medicine imaging in neurology, neurosurgery and psychiatry].

Analysis of use of nuclear medicine imaging (positron emission tomography and single photon emission computed tomography) in diagnosis, differential diagnosis and evaluation of treatment efficacy of central nervous system diseases is presented in this review. The possibility of radionuclide imaging techniques in different variants of dementia, Parkinson's disease, brain tumors is demonstrated on the basis of personal authors experience and recent literature data. Results of PET application in evaluating of the effecacy of stereotactic interventions in patients with anxiety obsessive disorders are also described in the review.

[Positron emission tomography with 18F-FDG compared with proliferative activity of tumor cells in different subtypes of non-Hodgkin lymphoma].

In the course of this study we determined the ability of positron emission tomography (PET) with the 18F-FDG to detect non-hodgkin lymphoma lesions, assess their proliferative activity and differentiate aggressive tumors from indolent. Tracer uptake in lymphoma was evaluated semiquantitatively by calculation of standardized uptake values (SUV). It was compared with tumor grade and proliferation fraction determined by Ki-67 staining. In patients with indolent lymphoma, mean SUV was 2.5 +/- 0.6. In patients with aggressive lymphoma a significantly higher 18F-FDG uptake was observed (mean SUV was 8.1 +/- 1.3). Linear regression analysis indicated significant correlation of 18F-FDG uptake to biopsy samples proliferation fraction in patients with diffuse large B-cell lymphoma (r = 0.55, p = 0.05) and indolent non-Hodgkin's lymphoma (r = 0.7, p < 0.05). In this clinical study 18F-FDG uptake correlates with the aggressiveness of malignant lymphomas and with biopsy samples proliferative activity.

[Evaluation of coronary bed function by positron emission tomography using 13N-ammonium during cold stimulation].

The purpose of the present investigation was to study the time course of changes in myocardial blood flow (MBF) in response to cold stimulation. Thirty-eight patients having risk factors of cardiovascular complications were examined. The time course of MBF changes was estimated by positron emission tomography (PET) using 13N-ammonium at rest and during a cold test (CT). Endothelium-dependent vasodilation of the brachial artery was determined from the results of a reactive hyperemia test, by applying ultrasound duplex scanning. No significant MBF increase in response to the cold test was an indicator of coronary arterial endothelial dysfunction at cardiac 13N-ammonium PET. Agreement of the results of brachial arterial ultrasonography during reactive hyperemia and cardiac 13N-ammonium PET in the presence of the cold test suggests that endothelial dysfunction is generalized. Cardiovascular risk factors, such as left ventricular hypertrophy, smoking, dyslipidemia, and diabetes mellitus, substantially affect coronary arterial function. Left ventricular hypertrophy is an independent factor that influences the amount of the coronary reserve and, in combination with endothelial dysfunction, worsens coronary microcirculation.

[Current possibilities of radiodiagnosis in liver tumors].

The report deals with potential of present-day techniques for radiological imaging, differential diagnosis and working out of modalities of treatment for primary and metastatic hepatic tumors. Results of complex examination (ultrasound, CT, MRI, PET using fluorine -18 FDG) of patients with benign and malignant tumors are discussed. Sensitivity and specificity of each procedure have been identified to be used in diagnosis of large-size tumors.

[Use of 18F-FDG PET scan in the diagnosis of large liver neoplasms and in the evaluation of therapeutic effectiveness].

The study involved 207 patients with large-size tumors. Results of 18FDG PET pointed to the basic factor of malignant transformation--foci of enhanced accumulation of radiological medicinal substances. Absence of ultrasound and CT-based evidence of such pathological accumulations contributed to interpretation of changes as benign ones. The effectiveness of chemotherapy was assessed by tumor metabolic response to treatment given at the time of 18FDG PET examination.

[Role of 18F-FDG PET scan in the differential diagnosis of large pancreatic masses].

Results of standard 18FDG PET and double-phase scanning were compared in the course of differential diagnosis of pancreatic cancer and chronic pseudotumorous pancreatitis, particularly, during exacerbation. PET diagnosis of cancer was confirmed in 6.5% while that of double-phase scanning--100%.

[Role of dynamic contrast-enhanced MR mammography imaging in the diagnosis of breast tumors].

Potential of contrast-enhanced MR imaging (MRI) in diagnosis of breast tumors was studied in 112 patients aged 18-64 (76 suspects and 36--after combined treatment). The method proved highly-effective and specific--92 and 81%, respectively. The best timing was 3 months after surgery and 8 months after irradiation. No significant advantage of either one- or polymolar contrast agents was observed. MRI is highly efficient in diagnosing hypervascular formations, tumor grading and making prognosis. It is a method of choice in evaluating neoadjuvant polychemotherapy findings and combined treatment monitoring.

[Role of 18F-FDG PET in tumor grading and evaluating effectiveness of therapy in malignant lymphomas].

The report compares the results of (multi-layer spiral computed tomography) (MSCT), 67 Ga citrate lymph scintigraphy and 18FDG PET in patients with Hodgkin's disease. The predictive significance of the latter method exceeded that of MSCT and ultrasound in diagnosing lymph node neoplasia below the diaphragm. As far as peripheral and mediastinal lymph nodes are concerned, the MSCT efficiency of the three procedures was comparable. Advantage was offered by PET in early evaluation of therapeutic effectiveness. Moreover, its practical significance for assessing tumor sensitivity to therapy as well as differentiation between viable tumor tissue and fibrosis was demonstrated.

[Proton magnetic resonance spectroscopy in postoperative radiochemotherapy of patients with cerebral glioblastoma].

The paper discusses the data from dynamic follow-up of immunohistologically confirmed glioblastomas of the brain using proton magnetic resonance imaging (+H MRI) (25). Study was undertaken before and after therapy and resumed for 6-8 months after. Cholin concentration peaks and N-acetyl-aspartate decrease in gliomas appeared to be higher than those in anaplastic astrocytomas. Moreover, N-acetyl-aspartate peaks were obliterated by large necrotic areas in glioblastoma. Instead, lipid and lactate concentrations peaked thus suggesting pathological changes. A necrotic area developed in the course of radiochemotherapy involving peaks for wide profile of lipid and lactate concentrations coupled with lowered levels of other metabolites.

[Evaluation of coronary bed function by positron emission tomography using 13N-ammonium during cold stimulation].

The present investigation was to study the time course of changes in myocardial blood flow (MBF) in response to cold stimulation. Thirty-eight patients having risk factors of cardiovascular complications were examined. The time course of MBF changes was estimated by positron emission tomography (PET) using 13N-ammonium at rest and during a cold test (CT). Endothelium-dependent vasodilation of the brachial artery was determined from the results of a reactive hyperemia test, by applying ultrasonic duplex scanning. No significant MBF increase in response to the cold test was an indicator of coronary arterial endothelial dysfunction at cardiac 13N-ammonium PET. Agreement of the results of brachial arterial ultrasonography during reactive hyperemia and cardiac 13N-ammonium PET in the presence of the cold test suggests that endothelial dysfunction is generalized. Cardiovascular risk factors, such as left ventricular hypertrophy, smoking, dyslipidemia, and diabetes mellitus, substantially affect coronary arterial function. Left ventricular hypertrophy is an independent factor that influences the size of the coronary reserve and, in combination with endothelial dysfunction, worsens coronary microcirculation.

[Twelve years' clinical experience in using positron emission tomography: advances and prospects].

The paper describes 12 years' experience in using positron emission tomography (PET) at the Russian Research Center of Radiology and Surgical Technologies to detect cancer, cardiac, and psychoneurological diseases, to make their differential diagnosis, and to evaluate the efficiency of their treatment. It shows the capacities of PET using various radiopharmaceutical agents in a broad spectrum of the above abnormalities and defines prospects for further development of the technique.