The potential role of FDG PET-CT in the characterization of the activity of Crohn's disease, staging follow-up and prognosis estimation: a pilot study.

OBJECTIVES: FDG PET-CT is a global, noninvasive, sensitive method to determine the location and activity of inflammatory lesions. Segmental FDG uptake is proportional with immune cell infiltration of bowel. Our aim was to evaluate prospectively the role of PET in patients with active Crohn's disease (CD) before and after one year's biological therapy, and to compare simple endoscopic score for CD (SES-CD), CD activity index (CDAI) and global PET scores. We also analyzed the prognostic value of initial PET scores. PATIENTS: Twelve patients were selected: six male/six female, ages between 18 and 39, average: 24 years, with CDAI values >300. METHODS: We scored the FDG uptake in the small intestine and the four colon segments (on a scale 0-3 for each), and summed them thus forming a global PET score. The scoring was based on the maximal standardized uptake value of the intestinal segment, related to the SUVmax of the liver (as a reference for normal tissue activity). The SES-CD, CDAI and global PET scores before and after treatment were statistically compared. RESULTS: There were significant changes in CDAI and SES-CD after therapy, PET scores improved only in patients' subgroup with high (>4) initial PET score, indicating good prognosis of biological treatment. In active disease, PET was more informative than endoscopy to access the extent of the inflammation, and small intestine involvement. CONCLUSIONS: FDG PET-CT score is a promising, noninvasive complementary method in the staging, treatment planning and follow-up of CD. Limitation of the study is the small number of patients.

The influence of the combination of carboxylate and phosphinate pendant arms in 1,4,7-triazacyclononane-based chelators on their 68Ga labelling properties.

In order to compare the coordination properties of 1,4,7-triazacyclononane (tacn) derivatives bearing varying numbers of phosphinic/carboxylic acid pendant groups towards 68Ga, 1,4,7-triazacyclononane-7-acetic-1,4-bis(methylenephosphinic) acid (NOPA) and 1,4,7- triazacyclononane-4,7-diacetic-1-[methylene(2-carboxyethyl)phosphinic] acid (NO2AP) were synthesized using Mannich reactions with trivalent or pentavalent forms of H-phosphinic acids as phosphorus components. Stepwise protonation constants logK1-3 12.06, 3.90 and 1.95, and stability constants with GaIII and CuII, logKGaL 24.01 and logKCuL 16.66, were potentiometrically determined for NOPA. Both ligands were labelled with 68Ga and compared with NOTA (tacn-N,N',N″-triacetic acid) and NOPO, a TRAP-type [tacn-N,N',N″- tris(methylenephosphinic acid)] chelator. At pH 3, NOPO and NOPA showed higher labelling efficiency (binding with lower ligand excess) at both room temperature and 95 °C, compared to NO2AP and NOTA. Labelling efficiency at pH = 0-3 correlated with a number of phosphinic acid pendants: NOPO >> NOPA > NO2AP >> NOTA; however, it was more apparent at 95 °C than at room temperature. By contrast, NOTA was found to be labelled more efficiently at pH > 4 compared to the ligands with phosphinic acids. Overall, replacement of a single phosphinate donor with a carboxylate does not challenge 68Ga labelling of TRAP-type chelators. However, the presence of carboxylates facilitates labelling at neutral or weakly acidic pH.

[11C-choline PET/CT in the diagnosis of prostate cancer -- Hungarian experience]. / 11C-kolin-PET/CT a prosztatarák diagnosztikájában -- a hazai tapasztalatok tükrében.

11C-choline has been used in the diagnosis and follow-up of patients with prostate cancer for years. Choline PET/CT has been available in human care since March, 2014 in our country. Unfortunately this examination has not been reimbursed by the National Health Insurance so far. We retrospectively analysed and assessed the results of 40 patients who underwent 11C-choline PET/CT on the basis of previous literature. As our study group was heterogeneous statistical analysis was not performed.

[Novel treatment opportunities in Graves' orbitopathy]. / Új lehetoségek az endokrin orbitopathia kezelésében.

Graves' orbitopathy is the most common extrathyroidal manifestation of Graves' disease. Up to now, curative treatment modalities for the most severe sight-threatening cases have not been developed. Here the authors summarize the treatment protocol of Graves' orbitopathy and review novel therapeutic options. They review the literature on this topic and present their own clinical experience. The authors point out that anti-CD20 antibody could positively influence the clinical course of Graves' orbitopathy. Selenium is efficient in mild cases. Further prospective investigations are warranted.

[New trends in functional medical imaging: quantitative methods]. / Újdonságok és új lehetoségek a funkcionális képalkotásban: kvantitatív módszerek.

Deriving quantitative measures from the medical imaging methods is a key issue for the optimal oncologic therapy, when the anatomical abnormalities and changes of the metabolic state of the tissues need to be characterized. In order to improve the effectiveness of the therapy, the results of medical imaging procedures should be comparable after two or more consecutive scans. There are several tomographic imaging applications (CT, MRI, SPECT and PET), but in this work we will focus on the quantitative capability of PET, because this method provides the most versatile possibilities for quantifying the resulting images.

[The role of FDG PET/CT for detecting the cause of fever of unknown origin in a clinical case]. / A (18)F-fluoro-dezoxiglükóz pozitronemissziós tomográfia/komputertomográfia szerepe az ismeretlen eredetu láz felderítésében, egy eset kapcsán.

The fever of unknown origin from time to time constitutes a serious clinical problem and nearly all diagnostic methods are involved to discover urgently its cause. According to literature data (18)F-fluoro-deoxyglucose PET/CT was successful in 25-70% of cases even in patients without any positive findings with conventional diagnostic techniques. The Hungarian National Health Fund does not include fever of unknown origin in the list of reimbursed (18)F-fluoro-deoxyglucose PET/CT indications. The authors try to illustrate the clinical problem with this case report. Fever of unknown origin persisted in a patient for a year, but conventional diagnostic procedures were unsuccessful to find the cause of the fever. Finally, (18)F-fluoro-deoxyglucose PET/CT indicated a metabolically active focus between the pancreas tail and the spleen. After a long-lasting antibiotic therapy the patient became symptomfree.

Automated procedure assessing the accuracy of HRCT-PET registration applied in functional virtual bronchoscopy.

BACKGROUND: Bronchoscopy serves as direct visualisation of the airway. Virtual bronchoscopy provides similar visual information using a non-invasive imaging procedure(s). Early and accurate image-guided diagnosis requires the possible highest performance, which might be approximated by combining anatomical and functional imaging. This communication describes an advanced functional virtual bronchoscopic (fVB) method based on the registration of PET images to high-resolution diagnostic CT images instead of low-dose CT images of lower resolution obtained from PET/CT scans. PET/CT and diagnostic CT data were collected from 22 oncological patients to develop a computer-aided high-precision fVB. Registration of segmented images was performed using elastix. RESULTS: For virtual bronchoscopy, we used an in-house developed segmentation method. The quality of low- and high-dose CT image registrations was characterised by expert's scoring the spatial distance of manually paired corresponding points and by eight voxel intensity-based (dis)similarity parameters. The distribution of (dis)similarity parameter correlating best with anatomic scoring was bootstrapped, and 95% confidence intervals were calculated separately for acceptable and insufficient registrations. We showed that mutual information (MI) of the eight investigated (dis)similarity parameters displayed the closest correlation with the anatomy-based distance metrics used to characterise the quality of image registrations. The 95% confidence intervals of the bootstrapped MI distribution were [0.15, 0.22] and [0.28, 0.37] for insufficient and acceptable registrations, respectively. In case of any new patient, a calculated MI value of registered low- and high-dose CT image pair within the [0.28, 0.37] or the [0.15, 0.22] interval would suggest acceptance or rejection, respectively, serving as an aid for the radiologist. CONCLUSION: A computer-aided solution was proposed in order to reduce reliance on radiologist's contribution for the approval of acceptable image registrations.

[The status of domestic PET/CT attendance in the light of the waiting list data]. / A hazai PET/CT-ellátás helyzete a várólista adatai alapján.

The aim of the study is to demonstrate the diagnostic and geographical distribution of the domestic PET/CT examinations financed by the OEP based on the data from the waiting list of the past 4 years. The analysis of the demonstrated data can support the rational usage of PET/CT examination contingents in the domestic oncological attendance, which has growing importance. PET examinations with oncological aims have started in Debrecen more than 10 years ago. In 2005 already 1500 PET examinations have been carried out. According to the governmental regulation accepted in 2006, OEP ensures the financing of the three PET/CT centers until 2012, which means 12,000 examinations in 2012. However, the number of domestic oncological patients requiring PET/CT examinations can reach the number of 20,000-30,000 patients. The study summarizes the number of patients who applied for PET/CT examinations for the first time and later again between 2006 and 2010, based on the data of the waiting list, and the change of the patient assigning diagnosis and the number of examinations carried out with 18F-FDG and with 11C-methionine. The study demonstrates the number of examinations by counties which characterize the population's access to PET/CT. The assigning diagnosis in 2007 was already widespread and focused on problems. After the regulation came in to force in 2008 the possibilities significantly decreased. Clinical cases which were efficiently examined with PET/CT earlier were left out from the indication list. The distribution by county is uneven, although the number of examinations increases year by year. The number of repeated examinations increases as well. As a conclusion, the annual PET/CT examination contingents are constantly exploited. This might seem sufficient, because the method has not become a part of the oncological routine in all counties. Although the current indication list includes the most frequent oncological cases requiring PET/CT, the abandoning of the less frequent ones narrowed the professional latitude, which is disadvantageous for the patients suffering from such diseases. The radiopharmacon supply of PET/CT centers is inadequate thus they cannot provide modern oncological diagnostic attendance in case of frequent types of cancer (such as prostate). In the long run the growing number of repeated PET/CT examinations built in the oncological professional protocol has to be taken into account.

Myocardial adrenergic innervation in patients with vasovagal syncope measured with 123I-MIBG uptake.

BACKGROUND: Data about biochemical abnormalities (catecholamines) during vasovagal syncope (VVS) are available, but adrenergic myocardial structural damage may be hypothesized as well. AIM: To study the global and regional adrenergic myocardial innervations in patients with VVS that was shown by head-up tilt table testing. PATIENTS AND METHODS: Fifteen adult patients with VVS were studied. The age of patients was 44+/-18 years (17-73), nine were female and six were male. According to the tilt test results, five patients had cardioinhibition, six patients had vasodepressor syncope and four patients suffered from mixed-type VVS. Ischemic heart diseases were excluded by normal Tc-MIBI rest-stress dipyridamol single-photon emission computed tomography (SPECT) results. A control group was formed from six healthy adult volunteers. To investigate cardiac sympathetic innervations 250-370 MBq iodine-123 meta-iodobenzylguanidine (I-MIBG) was used. Fifteen minutes after the intravenous administration of I-MIBG early, and 2-3 h later, delayed planar myocardial and tomographic (SPECT) scintigraphies were performed. The heart-to-mediastinum count ratio (H/M) was calculated for both early and delayed images, together with the decay-corrected change rates. The regional I-MIBG uptake was visualized on SPECT slices and polar map images. The regional uptake was considered pathological below 50% compared with normal uptake sites. RESULTS: Delayed H/M ratios significantly depended on group (analysis of variance: P=0.005), whereas early H/M values did not. Although the decay-corrected myocardial MIBG uptake increased in time in controls, less wash-in or even wash-out could be observed in the VVS groups; however, difference from the controls was significant only in the vasodepressor group (Dunnett's t-test: P<0.05). All patients had regional I-MIBG uptake deficit in different regions. CONCLUSION: In our patients with VVS, global I-MIBG deficit was present frequently, and all patients had regional adrenergic nerve function deficit. These alterations may play a role in causing clinical symptoms and have importance in staging and treatment planning.

[Prognostic value of FDG-PET in Hodgkin lymphoma for posttreatment evaluation. Long-term follow-up results]. / Az FDG-PET prognosztikai értéke Hodgkin-lymphomás betegek követésében - hosszú távú eredményeink.

UNLABELLED: In the past few decades Hodgkin lymphoma (HL) has become a highly curable malignant disease, as a result of using modern polychemotherapy and irradiation. Differentiation of active tumor from fibrosis or necrosis within residual radiographic masses represents a problem of interpretation. AIMS: The aim of this retrospective study is to assess the value of FDG-PET for prediction of remission or relapse in HL. PATIENTS AND METHODS: Data of 128 patients, who had residual masses on CT after completion of their planned treatment, have been analyzed. FDG-PET was performed between January 1995 and February 2005. RESULTS: The median duration of the follow-up from PET was 75.5 months (range: 20-180 months). 89 (70%) patients had negative and 39 (30%) patients had positive FDG-PET results. The numbers of true-positive, true-negative, false-positive and false-negative subjects were 29, 83, 10 and 6, respectively. Sensitivity of post-treatment FDG-PET was 83%, specificity 93%, positive predictive value 74%, negative predictive value 93%, and accuracy 88%. The difference between the event free survival of PET positive and negative cases is highly significant (p = 0.0000), according to the Mantel-Cox test. CONCLUSION: Our results, in accordance with literature, clearly indicate that patients with negative FDG-PET results are unlikely to progress or relapse during a long follow-up. However, false positive uptake is a problem. We have investigated the effect of age, histological subtype, clinical stage and the type of treatment on the accuracy, but on the basis of these facts we could not find any significant difference. However, the date of the investigation influenced the results: before 2000 the number of false results was significantly higher than after that time, which shows the importance of investigators' experience.

First comparative results about the direct effect of traditional cigarette and e-cigarette smoking on lung alveolocapillary membrane using dynamic ventilation scintigraphy.

INTRODUCTION: Dynamic inhalation scintigraphy (DIS) with technetium-99m-diethylenetriamine-pentaacetate aerosol is a useful nuclear medicine procedure for staging and monitoring the damage of alveolocapillary membrane. The e-cigarette is a new popular smoking device producing vapor from the nicotine solution. Many studies have shown that e-cigarettes appear to be safer than smoking, but there are still debates to what extent e-cigarettes are less harmful than smoking.In this prospective, self-controlled study, we compared DIS results among volunteers smoking an e-cigarette and their results after they returned to traditional cigarette smoking for a week. PARTICIPANTS AND METHODS: We included 24 healthy volunteers into this study who regularly used e-cigarette containing at least 10 mg nicotine/ml. We performed baseline DIS study in volunteers with e-cigarette smoking and then we asked them to return to traditional cigarette smoking for a week. Conventional respiration tests were also measured. We statistically analyzed the effect of traditional cigarette on clinical parameters and pulmonary clearance of the radiopharmacon. RESULTS: There was no significant change in the parameters of peak expiratory flow rate and Tiffeneau-Pinelli index respiration tests; forced vital capacity and forced expiratory volume in 1 s slightly decreased (P<0.05), whereas the exhaled CO and COHb levels were significantly higher at traditional cigarette use (P<0.0001), and increased in every case. The pulmonary clearance was significantly faster at traditional cigarette smoking compared with e-cigarette use (P<0.0001). CONCLUSION: On the basis of our results, we suppose that e-cigarette smoking is less harmful to the lung function than a traditional cigarette, and it can be recommended to heavy smokers who are unable to stop smoking.

The role of 99mTc-DTPA retrobulbar SPECT in staging and follow-up of Graves' orbitopathy.

The pathogenesis of Graves' orbitopathy (GO) is not completely understood. Coexistent hyperfunction of the thyroid gland is frequent; however, GO may also coexist with hypo- or euthyrodism. The course of GO is largely independent of thyroid function, although elevated serum TSH is known to negatively interfere with GO course. GO is severe in 10% of the cases; sight threatening complications may also develop. A successful therapy of GO requires the assesment of both the severity and activity of orbital inflammation. Based on relevant studies and our own experiences, the possible management choices are reviewed here. For this purpose, we compare the clinical value of imaging techniques for detecting the activity of the disease. During the last 15 years, we used 99mTc-DTPA retrobulbar SPECT routinely in more than 1400 patients to facilitate the right therapeutic decision. This diagnostic utility simplified management decisions compared to previously applied alternative techniques. We recommended the routine use of 99mTc-DTPA retrobulbar SPECT for the evaluation and follow-up of GO.

Early Stage Graves' Disease is Uniformly Accompanied by Orbital Immune Activity even in Patients who Fail to Develop Orbithopathy during Follow-up.

PURPOSE: Graves' orbitopathy (GO) is a complication of Graves' disease (GD), the development of which cannot be predicted at the time of diagnosis of GD. Our aims were (i) to test if orbital 99mTc-labelled diethylenetriamine pentaacetic acid single-photon emission computer tomography (DTPA SPECT) can predict development of GO later during the course of the disease and (ii) to study whether orbital immune activity can be detected in GD patients who do not develop GO during follow-up. METHODS: Fifty-four orbits of 27 patients with newly diagnosed GD were entered into the case-control study. Individuals showing signs of GO at enrolment were excluded. During the two-year follow-up, eye signs were recorded every 3 months. Orbital DTPA uptakes on SPECT images were measured when entering the study and at the end of the follow-up period, or when clinical signs of GO developed, whichever occurred first. RESULTS: During the follow-up, 6 patients (22%) were diagnosed with GO. There was no significant difference between the initial DTPA uptakes of the patients with or without later developing GO (10.45±1.72 MBq/cm3 vs. 9.18±1.18 MBq/cm3 respectively). However, the DTPA uptakes of both GD groups (ie. with and without GO) were higher than that of the control group (7.45±1.36 MBq/cm3, p<0.05). CONCLUSIONS: We have shown that GD is accompanied by moderate orbital immune activity in GD patients without GO, irrespective of later development of GO. Why this orbital autoimmunity remains subclinical in the majority of the cases, and progresses into clinically detectable GO in others, remains unclear.

Holistic polar map for integrated evaluation of cardiac imaging results.

Polar map display (PM) is a comprehensive interpretation of the left ventricle. This is a non-rigid registration of the left ventricle originally for the visual and quantitative analysis of tomographic myocardial perfusion scintigrams. In this scheme the maximal-count circumferential profiles of well-defined short- and long-axis planes are plotted to a map showing the distribution of the perfusion tracer onto a two-dimensional polar representation. The usual coronary artery distribution is often indicated on the PMs of SPECT studies by referring to the regions of the three main coronary branches, nevertheless, the individual variations may differ extensively. We set out to develop an Access (Microsoft)-based computer program that permits an integrated evaluation of the imaging results (coronary angiography, echocardiography and SPECT) on patients with coronary artery disease. This semi-quantitative registration of the coronary tree to a PM focused on the relation between the supplying coronary branches and the myocardial regions of the 16-segment left ventricular evaluating model. All the recorded anatomical and functional data were related to these 16 left ventricular segments, which allowed the direct comparison and holistic synthesis of the results. Two projections were taken into consideration for generation of the coronary PM: from the right anterior oblique projections, the left anterior descendent (LAD)/right coronary artery (RCA) border was assessed through the comparison of the left and right coronary angiograms. The terminations of the visually detected end-arteries showed the separation of the myocardial beds supplied by the two branches. The border of the myocardial beds on the polar map was determined on the "vertical axis" of the local coordinate system. The RCA/ left circumflex (LCx) separation can be determined from the left anterior oblique view. In this projection, the left ventricular septal edge was delineated by the LAD, while the LCx indicated the lateral epicardial surface. The individual coronary artery circulation was typified from among 12 variations in the Holistic Coronary Care program. With this determination of the individual coronary circulation, the lesion-associated segments are generated automatically by the software. The lesion-associated regions are defined as the myocardial bed of a diseased artery distal to the lesion. The PMs generated from the coronary angiographic results were compared with those of 99Tc-labelled MIBI single photon emission computed tomography (SPECT) in order to test the accuracy of the localizing method. The overlap between the segments associated with the coronary lesion and the stress perfusion defects (<80% relative MIBI activity during stress tests) was analyzed in 10 patients with (sub)total coronary occlusion after myocardial infarction. The distributions of the segments with stress perfusion defects on MIBI SPECT gave positive and negative predictive values of coronary occlusion of 0.94 and 0.8, respectively. According to the 16-segment wall motion analysis by echocardiography, the positive and negative predictive values of coronary occlusion for wall motion abnormality were 0.82 and 0.76, respectively. While the distal part of the subtended region usually demonstrated a higher degree perfusion abnormality than the proximal part, the high positive predictive value proved that, during the stress condition, the perfusion defect could be detected in practically all the subtended regions. The low negative predictive value of the coronary lesion for the wall motion abnormality was associated with the remodeling of the entire left ventricle.

[Effects of autologous bone marrow derived CD34+ stem cells on the left ventricular function following myocardial infarction]. / A csontvelo eredetu CD34+ ossejtek hatása a bal kamra funkciójára akut miokardiális infarktust követoen.

Both experimental and human clinical studies executed in the last 5 years suggested that bone marrow derived cells may participate in the healing process after myocardial infarction. A number of small clinical trials indicated mild or moderate beneficial effect of intracoronary administration of bone marrow derived stem cells after myocardial infarction. Most of the studies used mononuclear cell fraction; due to the cellular heterogeneity of this cell population the type of the effective subpopulation was not known. We investigated the safety and functional effects of the autologous bone marrow CD34+ stem cells after intracoronary administration in patients with recent myocardial infarction. 8 patients with impaired left ventricular function were transplanted with CD34+ bone marrow stem cells 12 +/- 1 day after the acute coronary event. 2D-echocardiography, FDG-PET and MIBI-SPECT were performed before transplantation and 6 month later. During the 6-month follow-up the global left ventricular function (basal EF 37.3 +/- 2.9%, after cell therapy 44.8 +/- 4.1%) and regional viability / metabolism increased significantly (17.6 +/- 13.5%). The increase of myocardial perfusion in the infarct region was tendentious but not significant. Our results demonstrate for the first time that the CD34+ subpopulation of bone marrow derived stem cells improves left ventricular function and viability after myocardial infarction.

Paclitaxel modifies the accumulation of tumor-diagnostic tracers in different ways in P-glycoprotein-positive and negative cancer cells.

AIM: To study how paclitaxel treatment modifies the accumulation of tumor-diagnostic radiotracers in P-glycoprotein (P-gp) positive and negative cancer cells. METHODS: The accumulations of different P-gp substrates, including rhodamine 123, daunorubicin and [(99m)Tc]hexakis-2-methoxybutyl isonitrile ((99m)Tc-MIBI), were measured in P-gp-positive (A2780AD) and P-gp-negative human ovarian carcinoma cells (A2780) and JY human lymphoid B cells. The uptakes of the tumor-diagnostic tracers (11)C-choline and 2-[(18)F]fluoro-2-deoxy-d-glucose ((18)FDG) were measured in the same cell lines. The P-gp expression and function were demonstrated by flow-cytometry. RESULTS: The (18)FDG measurements revealed that the glucose metabolic rate was significantly higher (p<0.01) in the P-gp-positive A2780AD cells than in the P-gp-negative cells. Paclitaxel (1-70microM) increased the (18)FDG uptake (up to 200%) of both P-gp-positive and P-gp-negative cells, whereas it did not modulate their (11)C-choline uptake. Paclitaxel reinstated the (99m)Tc-MIBI accumulation of the A2780AD cells (to 1500% of the control) in a concentration-dependent manner, while it increased the uptake of the P-gp-negative cells to a lesser extent (to a maximum of 200% of the control). CONCLUSION: Paclitaxel modifies the uptake of tumor-diagnostic tracers in both P-gp-dependent and independent manners. Interpretation of the multifactorial effects of paclitaxel may promote a correct in vivo diagnosis of P-gp-positive and P-gp-negative tumors.

Hand perfusion with 99mTc-HSA in patients expecting to undergo coronary bypass surgery: elaboration of a new complex diagnostic protocol for the safe removal of a radial artery graft.

BACKGROUND: The Allen test is used worldwide for radial artery graft removal. The postoperative examination of our patients' hand function and circulation proved that beside the transient neurological complications chronic hand circulatory disorders may arise. AIM: To develop a non-invasive method suitable for an objective evaluation of the hand's circulation to make it possible to use radial arteries safely for the revascularization of coronary arteries. METHODS: We examined 35 patients. After selective compression of the radial and ulnar arteries of both hands, we injected 400 MBq (99m)Tc-HSA intravenously and acquired 240 images, each of 1 s. After 30 s we released the ulnar artery first, and after 120 s the radial artery, too. Then computer analysis was performed. RESULTS: The patients could be divided into two groups. In the majority of them, releasing only the ulnar artery resulted in a good circulation of the fingers. It meant that the time-activity curve rapidly reached its maximum, and the activity did not change even after releasing the radial artery. In a smaller proportion of the patients the activity of the fingers increased only slowly, and did not reach a plateau even after 30 s. Following the release of the radial artery a further increase in the activity could be observed. We assume that the latter patient group is at risk of consequent circulatory disorder of the fingers after the removal of the radial artery, whereas in the former group the artery could be removed safely. CONCLUSIONS: Hand perfusion with (99m)Tc-HSA is useful in patients selected for coronary bypass operations, so we recommend the introduction of this method as a routine examination before the removal of the radial artery in patients with an abnormal Allen test.

Effects of vinpocetine on the redistribution of cerebral blood flow and glucose metabolism in chronic ischemic stroke patients: a PET study.

The pharmacological effects of the neuroprotective drug vinpocetine, administered intravenously in a 14-day long treatment regime, on the cerebral blood flow and cerebral glucose metabolism in chronic ischemic stroke patients (n=13) were studied with positron emission tomography in a double-blind design. The regional and global cerebral metabolic rates of glucose (CMRglc) and cerebral blood flow (CBF) as well as vital physiological parameters, clinical performance scales, and transcranial Doppler parameters were measured before and after the treatment period in patient groups treated with daily intravenous infusion with or without vinpocetine. While the global CMRglc values did not change markedly as a result of the infusion treatment with (n=6) or without (n=7) vinpocetine, the global CBF increased and regional CMRglc and CBF values showed marked changes in several brain structures in both cases, with more accentuated changes when the infusion contained vinpocetine. In the latter case the highest rCBF changes were observed in those structures in which the highest regional uptake of labelled vinpocetine was measured in other PET studies (thalamus and caudate nucleus: increases amounting to 36% and 37%, respectively). The findings indicate that a 2-week long intravenous vinpocetine treatment can contribute effectively to the redistribution of rCBF in chronic ischemic stroke patients. The effects are most pronounced in those brain regions with the highest uptake of the drug.

Volume changes in intra- and extraorbital compartments in patients with Graves' ophthalmopathy: effect of smoking.

The objective of this study was to demonstrate the effect of smoking history on soft tissue expansion in specific orbital compartments in patients with Graves' ophthalmopathy. The volumes of the rectus muscles, intra and extraorbital connective, and soft tissues were measured in 110 orbits of 35 patients and 20 control subjects. Data sets from current smokers, ex-smokers, and non-smokers were compared. The total number of cigarettes smoked was calculated, and it was used as an estimate for the severity of smoking (cumulative smoking). The volume measurements were performed on T1-weighted contiguous transversal magnetic resonance images of the orbits. Connective tissue volumes were influenced by smoking history, while muscle volumes were not affected. Ex-smokers had larger amount of extraorbital connective tissue than current smokers (p = 0.012), and this volume showed a good correlation with the number of cigarettes smoked (r = 0.539, p < 0.05). In current smokers, the amount of intraorbital connective tissue correlated well with the cumulative smoking (r = 0.635, p < 0.001). We conclude that connective tissue volumes in certain orbital compartments correlate well with cumulative smoking. Extraocular muscle volumes are not influenced by smoking in patients with Graves' ophthalmopathy.

Biphasic accumulation kinetics of [99mTc]-hexakis-2-methoxyisobutyl isonitrile in tumour cells and its modulation by lipophilic P-glycoprotein ligands.

AIM: To study the accumulation and washout kinetics of [99mTc]-hexakis-2-methoxyisobutyl isonitrile (99mTc-MIBI) in MDR positive and MDR negative tumour cells and how this is modified by lipophilic P-glycoprotein ligands. METHODS: The tumour cells were incubated in the presence and absence of the ligands and the uptakes of 99mTc-MIBI, rhodamine 123 and 2-[18F]fluoro-2-deoxy-D-glucose (18FDG) were measured. RESULTS: The accumulation of 99mTc-MIBI in the tumour cells followed biphasic kinetics. Verapamil and cyclosporin A increased the membrane fluidity and significantly enhanced the 99mTc-MIBI uptake of the MDR negative cells, while the rhodamine 123 uptake was not affected. Verapamil significantly increased the uptake of rhodamine 123 and 18FDG but did not modify that of 99mTc-MIBI in the MDR positive cells. Cyclosporin A significantly increased the 18FDG uptake of the MDR positive and negative tumour cells; these effects were ouabain-sensitive. Depolarization of the cytoplasmic membrane, acidification of the extracellular medium and the administration of CCCP decreased the accumulation of 99mTc-MIBI and rhodamine 123 uptake in the tumour cells. CONCLUSIONS: Lipophilic P-glycoprotein ligands modified the biphasic accumulation kinetics of the 99mTc-MIBI uptakes of MDR negative and positive tumour cells in different and complex ways and could therefore mask the P-glycoprotein pump-dependent changes in tracer accumulation.