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BACKGROUND: 18F-FDG PET/CT has become an important tool in diagnosis of prosthetic vascular graft infections (PVGI). The aim of the study was to identify the patterns of vascular graft infection in 18F-FDG PET/CT. MATERIAL AND METHODS: The study was performed in 24 patients with vascular graft infection, in 17 patients implanted in an open surgery mode and in 7 patients by endovascular aortic repair (EVAR). Vascular prostheses were evaluated by two visual scales and semi-quantitative analysis with maximum standardized uptake values (SUV max). RESULTS: In the 3-point scale: 23 patients were in grade 1 and one patient was in grade 2. In the 5-point scale: 19 patients were in grade 5 with the highest activity in the focal area, 4 patients were in grade 4 and one patient in grade 3. The visual evaluation of 18F-FDG PET/CT study revealed that peri-graft high metabolic activity was associated with occurrence of morphological abnormalities (n = 21) like gas bubbles and peri-graft fluid retention or without abnormal CT findings (n = 3). The presence of the gas bubbles was linked to higher uptake of 18F-FDG (p < 0.01, SUVmax 11.81 ± 4.35 vs 7.36 ± 2.80, 15 vs 9 pts). In EVAR procedure, the highest metabolic activity was greater than in classical prosthesis (SUVmax 21.5 vs 13). CONCLUSIONS: 18F-FDG PET/CT is a very useful tool for assessment of vascular graft infections. CT findings like gas bubbles, or peri-graft fluid retention were associated with significantly higher glucose metabolism; however, in some cases without anatomic alterations, increased metabolic activity was the only sign of infection.

This review article discusses the utility of 18F-FDG PET/CT in diagnosis and management of vascular disease. We stress usefulness of this method in large vessel inflammation and infection. In our work we based on the literature analysis and clinical cases diagnosed in our institution by use of 18F-FDG PET/CT. The literature exploration was focusing on vascular inflammation and infections and 18-FDG PET. The search was performed on PubMed database and cross referencing. We present the practical review with several images of vascular diseases like: Takayasu arteritis, giant cell arteritis, vascular graft infections, abdominal aortic aneurysm infections and cases of aortitis and periaortitis. From this work inflammation associated with atheromatic process and vulnerable atherosclerotic plaque we excluded. 18F-FGD PET/CT is a sensitive metabolic, reliable, non-invasive imaging modality suitable for diagnosis and follow-up of inflammation and infections in vascular system.

OBJECTIVE Large cell pulmonary neuroendocrine carcinoma (LCNEC) is a poorly differentiated and high-grade neoplasm. It is positioned between an atypical carcinoid and small cell neuroendocrine carcinoma of the lung in a distinct family of pulmonary neuroendocrine tumors. The aim of our study was to detect somatostatin receptors in this uncommon malignancy and to evaluate the sensitivity of somatostatin receptor scintigraphy (SRS) in LCNEC staging. METHODS We analyzed data of 26 patients (mean age: 61.5±7.9 years) with histologically confirmed diagnosis of LCNEC, including 18 cases not treated surgically and eight patients after the resection of the primary tumor. SRS was carried out with technetium-99m ethylene diamine-diacetic acid/hydrazinonicotinyl-Tyr3-octreotide (Tc-TOC). A visual analysis of scintigraphic images was done with reference to conventional imaging modalities (computed tomography and bone sicintigraphy). RESULTS SRS sensitivity for the detection of primary lesions, supradiaphragmatic metastases, and infradiaphragmatic metastases was 100, 83.3%, and 0%, respectively. Five out of 13 metastases to the liver appeared on SRS as photopenic foci, visible on the background of physiological hepatic activity. Only one of the nine metastases to the skeletal system was found by SRS with sensitivity as low as 11.1%. The overall SRS sensitivity for the detection of secondary lesions and of all lesions was 54.8 and 62.2%, respectively. CONCLUSION Within a rather large series of LCNEC, the primary tumor showed an uptake of Tc-TOC in all cases, whereas some metastases did show Tc-TOC uptake and some others did not.

This study aimed to assess the impact of 99mTc-EDDA/HYNIC-TOC (99mTc-TOC) somatostatin receptor scintigraphy (SRS) in clinical practice.One hundred seventeen patients were divided into 6 groups: 1, initial detection and localization of suspected neuroendocrine tumor (NET); 2, tumor staging before therapy; 3, staging of NET of unknown origin, 4, restaging after surgery of primary tumor; 5, diagnosis of solitary pulmonary nodules (SPNs), and 6, follow-up after "cold" somatostatin analogues treatment.In group 1, clinical suspicions were not confirmed in any of the patients; in group 2, most of the primary lesions showed overexpression of somatostatin receptors (SSRT); in group 3, the primary tumor was not identified in any of the patients; in group 4, recurrences were depicted in 7 out of 47 patients; in group 5, only 1 malignant SPN was detected, and in group 6, regression of primary mass and metastases were seen on follow-up SRS in 1 patient.99mTc-TOC SRS is useful in staging of SSRT-overexpressing tumors of known and unknown primary origin, as well as in restaging after primary tumor surgery. This method is less effective in detecting suspected NET and assessing SPNs. Further investigation is necessary to evaluate the usefulness of SRS in monitoring patients after biological treatment.

Artificial Neural Networks (ANN) may be a tool alternative and complementary to typical statistical analysis. However, in spite of many computer applications of various ANN algorithms ready for use, artificial intelligence is relatively rarely applied to data processing. This paper presents practical aspects of scientific application of ANN in medicine using widely available algorithms. Several main steps of analysis with ANN were discussed starting from material selection and dividing it into groups, to the quality assessment of obtained results at the end. The most frequent, typical reasons for errors as well as the comparison of ANN method to the modeling by regression analysis were also described.

Radionuclide ventriculography enables such parameters of the left ventricular (LV) function as the ejection fraction (EF), ejection rate (ER) and filling rate (FR) to be measured correctly. The impairment of the LV function in coronary artery disease (CAD) results in an increase in plasma brain natriuretic peptide (BNP). The aim of this study was to check whether the reduction of the average filling rate (AFR) leads to an increase in plasma BNP levels in patients with CAD and nEF and whether that increase is comparable to that occurring in subjects with a reduced PER.The study population comprised 69 patients with CAD and 18 healthy subjects--a control group (CG). In all cases radionuclide ventriculography was performed at rest and the plasma BNP level was estimated.The plasma BNP concentration was significantly higher in the group with CAD than in those with CG . In patients with CAD and a decreased LVEF (dEF), the BNP level was significantly higher than in those with normal LVEF (nEF). In the subgroup with nEF and an AFRor = 1.04 EDV/s, the level of plasma BNP was significantly higher than in that with an AFR1.04. In the total CAD group, a significant correlation was found between plasma BNP concentrations and the LVEF, PER and AFR. In patients with nEF, the level of plasma BNP correlated only with the AFR.It is concluded that the diastolic dysfunction of the left ventricle in patients with CAD leads to an elevation of plasma BNP concentrations despite the normal ejection fraction. A diastolic dysfunction of the left ventricle affects the BNP plasma concentration to a greater degree than a systolic dysfunction.

In CAD, left ventricular function depends on the condition of myocardial perfusion, hence it may be presumed that blood flow abnormalities may enable the LVEF to be predicted. The aim of the study was to apply an Artificial Neural Network (ANN) to investigate the relationships between myocardial perfusion and LVEF, measured simultaneously.gSPECT examinations were performed in 95 patients with CAD, divided into training (n = 50) and testing (n = 45) groups. using the acquired data, in each subject the LVEF was calculated and a perfusion polar map was constructed and divided into 25 segments. Based on results obtained in the training group, a characteristic configuration of segments was defined, with features enabling differentiation between the individual subjects of that group. The set of those segments, as well as the corresponding LVEF values enabled the optimum network architecture to be constructed and trained. The trained ANN was verified by application to the testing group.Using the above-described procedure, 15 polar map segments were defined which enabled the patients of the training group to be differentiated sufficiently enough to make their further recognition possible. The optimal network structure consisting 25 neurons was obtained by comparing the activity in those segments in individual subjects with corresponding LVEF values. Based on the above model, the obtained network was able to reproduce learning data (r = 0.832; learning error = 4.84%) and to apply the gained knowledge to the testing cases (r = 0.786; testing error = 4.99%).The obtained network can generalise learned information. To predict LVEF, some polar map segments should be excluded from the analysis. Erroneous LVEF prediction may occur resulting mainly from conditions independent from perfusion abnormalities.

The most common radionuclide procedures for parathyroid imaging are (99m)Tc-MIBI/ (99m)Tc pertechnetate subtraction scintigraphy and (99m)Tc-MIBI double-phase imaging, with estimation of MIBI wash-out rate. Those two methods are by some authors regarded as complementary techniques, yielding the best evaluation of parathyroid gland if performed conjointly. By such an approach it seems reasonable to substitute the visual assessment of neck scintigrams and semiquantitative evaluation of MIBI wash-out rate with a single, common procedure. The aim of this study was application of the Artificial Neural Network (ANN) simulated by the computer program to detection and localisation of pathological parathyroid tissue in the planar neck scintigrams.The applied algorithm was based on simultaneous data processing in sets of 3 single pixels, each of them belonging to one of the three consecutive neck scintigrams generated 20 min. after (99m)TcO(4 )- administration, 10 min. after (99m)Tc-MIBI injection and 120 min. after (99m)Tc-MIBI injection, respectively. Those scintigrams were aligned which each other according to the same vertical and horizontal co-ordinates. The training patterns were obtained from 25 patients by searching for maximum count numbers within small ROIs drawn in selected scintigraphic areas, arbitrarily classified and coded in a numerical scale. In 10 pts the results of ANN simulation were compared with those obtained by common conventional assessment of two radionuclide parathyroid examinations: subtraction method and (99m)Tc-MIBI double-phase imaging.The training patterns processed by the neural network showed a close relationship with the results of visual assessment of original neck scintigrams, with R square coefficient R(2) = 0.717, and standard error equal to 0.243. Similar comparison between original data and results of multidimensional regression analysis yielded weaker relationship, with R(2) = 0.543 and standard error 0.567. Parametric images obtained by the neural network presented regions with homogeneously distributed, relatively high activity, greater than or equal to 750 cts/pixel, visualized in areas of confirmed abnormal parathyroid location. In all 10 patients with suspected parathyroid adenoma results obtained by ANN simulation agreed with those by conventional methods. In five of these cases no parathyroid abnormalities were found. In the remaining 5 subjects results of both approaches were positive but the abnormalities were depicted more distinctly and visualised more clearly in parametric images received by ANN than in original scans.Application of trained ANN enables objective and quantitative detection and localisation of parathyroid adenoma and is a good alternative for conventional radionuclide imaging procedures used in diagnosing parathyroid abnormality. Including in neural network simulation not only scintigraphic data, but also clinical symptoms and/or some other indicators of parathyroid abnormality, parathormone level first of all, should be a next step in developing a procedure for assessing parathyroid abnormality, of high diagnostic accuracy.

Biventricular cardiac pacing has been used as a complementary form of therapy in patients with severe heart failure. The aim of this study was to evaluate the effect of the synchronous stimulation of both ventricles on the heart function measured by gated blood pool study (GBP).Ten patients (9 men and 1 woman aged 53-74 years) with end-stage heart failure (HF) were studied. In all patients long-term biventricular pacing (BV) was applied. The obtained results were compared with single-chamber stimulation in 5 patients and with sinus rhythm (SR) in 8 patients. All patients underwent repeated GBP with RBC labelled with 740 MBq of 99 mTc-pertechnetate. The LVEF was calculated according to the standard method based on the count rates. Phase analysis was performed with the standard method using first Fourier element.Clinically in almost all patients moderate to important symptomatic improvement has been observed. The analysis of LVEF values revealed that BV pacing resulted in significantly higher values only in comparison with SR (21.6% +/- 10.3 v. 20.1% +/- 10.1; p0.05). The phase shift between both ventricles by BV pacing was positive and similar to that obtained with SR and RV stimulation (14.0 degrees +/- 29.6 v. 13.4 degrees +/- 37.6 and 7.4 degrees +/- 26.5 v. 6.0 degrees +/- 17.1 respectively). However, in comparison with LV pacing, BV stimulation revealed a change of dominant conduction abnormalities with a delay of RV contraction in relation to LV (9.0 degrees +/- 17.5 v. -3.0 degrees +/- 11.4).Biventricular pacing results in slight improvement of LVEF in patients with heart failure and can be considered a promising approach in patients with end-stage heart failure. Synchronous stimulation of both ventricles not always results in decrease of interventricular shift, however that observation requires further studies on a larger population.

Animal and clinical studies have shown that exercise can deteriorate myocardial contractile function. The aim of this study was to examine whether the decrease of LVEF measured with gated SPECT lasts as long as 3 hours after exercise.46 patients with CAD and a control group comprising 10 healthy subjects were studied. All patients underwent myocardial perfusion gated SPECT with (99m)Tc-tetrofosmin at rest and during stress. SPECT was started 1 hour p.i. at rest and twice - 1 hour and 3 hours after injection at stress. LVEF values were calculated by the method of Germano, using QGS software.LVEF values measured at all time points were significantly lower in CAD patients than in control group. In normals mean LVEF values 1h after rest injection were similar to those obtained 1 and 3 hours after stress injection (59.0 +/- 4.1 v. 60.0 +/- 5.9 v. 58.0 +/- 4.6 respectively; p0.05). One hour post exercise a decrease of LVEF was observed in 2 patients and 3 hours after injection also in 2 patients. CAD subjects showed slightly lower LVEF values determined 1h after stress than 1 hour after rest injection (50.8 +/- 13.6 v. 49.3 +/- 12.8; p0.05). More expressed reduction of LVEF was observed 3 hours after stress injection as compared to both rest and stress study (50.8 +/- 13.6 v. 46.0 +/- 12.2; p0.001 and 49.3 +/- 12.8 v. 6.0 +/- 12.2; p0.001 respectively). One hour post exercise, a decrease of LVEF values was observed in 18 patients and 3 hours after injection in 36 patients out of 46.In the majority of patients with CAD physical stress applied for the purposes of myocardial perfusion SPECT study results in an impairment of the LV function. The impairment of the LVEF caused by physical stress is observed 1 hour after exercise, but it increases markedly in frequency and grows stronger during the next 2 hours. Patients with CAD who underwent cardiac examination connected with physical stress should remain under observation for several hours after termination of exercise.

Somatostatin receptor scintigraphy (SRS) is useful in diagnosing tumours with increased expression of somatostatin receptors. Lymphoma cells are known to express somatostatin receptors; however, the application of indium-labelled analogues in children is limited. The aim of this study was to investigate whether the technetium-labelled somatostatin analogue, depreotide, may be useful in diagnosing and staging malignant lymphoma in children. Fifteen children (mean age 13.8 years) with malignant lymphoma were studied (eight with Hodgkin's lymphoma and seven with non-Hodgkin's lymphoma). All children were investigated for verification of staging established by other modalities. Imaging was performed 3-5 h after administration of 300-550 MBq (99m)Tc-depreotide. All patients underwent whole-body scan and single-photon emission tomography of the chest and/or abdomen. Images were assessed visually. In all patients, foci of increased tracer uptake were found. The neck and thorax were the most frequent lesion localisations. Abdominal lesions were found in four patients, and bone lesions in three. In two patients, diffusely increased uptake was observed throughout the skeleton (verified as representing bone marrow involvement). In 11 patients, the number of abnormal sites detected by SRS was greater than that detected by CT. Based on radionuclide examination, three children were upstaged and none were downstaged. It is concluded that (99m)Tc-depreotide shows increased accumulation in pathological sites in malignant lymphoma in children. SRS with (99m)Tc-depreotide provides a single-day imaging method with high sensitivity in lymphoma and with all the advantages of a technetium-labelled compound. Further studies are required on the specificity and the possible value of (99m)Tc-depreotide in the follow-up of these patients.

Nitroglycerin (Ntg) is known to increase blood flow to the hypoperfused myocardial area and thus to reduce regional ischaemia of the heart muscle in coronary artery disease (CAD). The aim of this study was to assess the effect of a therapeutic dose of Ntg on 99mTc-Tetrofosmin uptake defects occurring in patients (pts) with CAD in myocardial SPECT at rest. The study population comprised 34 pts with CAD. All subjects underwent myocardial perfusion SPECT at rest, using 2-day, protocol. On the first day 99mTc-Tetrofosmin was injected in baseline conditions and on the second day, after sublingual administration of 0.5 mg Ntg. The baseline examination revealed altogether 78 Tetrofosmin uptake defects in all 34 pts. The SPECT after Ntg showed improved tracer uptake in 33/78 perfusion defects in 18/34 pts, no change in 29/78 defects in 7/34 cases and more reduced tracer uptake in 16/78 defects in 9/34 pts. No explicit, significant relationship was found between 99mTc-Tetrofosmin uptake changes after Ntg on the one hand and the number of involved vessels, degree of coronary artery stenosis, history of myocardial infarction and LV global and regional function on the other. It is concluded that sublinqual administration of Ntg may result in improvement as well as in deterioration of regional perfusion defects, assessed with 99mTc-Tetrofosmin in CAD. The relationships between Ntg-augmented changes in uptake defects of this tracer on the one hand and conditions of the LV function and severity of heart muscle perfusion abnormalities on the other are unclear and should be verified on a larger study population.