Ildikó Garai

99mTc-HMPAO labelled leukocyte scintigraphy in patients with rheumatoid arthritis: A comparison with disease activity

The aim of this study was to test the applicability of 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO) labelled leukocyte joint scintigraphy in the assessment of disease activity in 21 patients with rheumatoid arthritis, and to compare leukocyte scintigraphy with the Disease Activity Score (DAS), a validated activity index developed by the European League Against Rheumatism (EULAR). Twenty-one patients with rheumatoid arthritis were investigated by using 99mTc-HMPAO labelled leukocyte joint scintigraphy. The clinical and laboratory data were recorded, and the DAS was calculated and compared with the scintigraphic results in each case. A relatively high DAS score (4.71±1.07) was found in the majority of patients. The degree of accumulation of 99mTc-HMPAO leukocytes showed no correlation with a patients age, gender, duration of disease, use of disease modifying anti-rheumatic drugs (DMARDs), visual analogue scale (VAS), Richie index, DAS, or any laboratory parameters. In contrast, a significant correlation was found between the global regional accumulation of the labelled leukocytes of the hands and feet, and the swollen-joint count. It is concluded that radiolabelled leukocyte scintigraphy could become one of the promising methods in the assessment of disease activity in patients with rheumatoid arthritis.

Changes in Cerebral Blood Flow Detected by SPECT in Type 1 and Type 2 Diabetic Patients

Although macrovascular complications are typical for type 2 diabetes mellitus (T2DM), cerebral microvascular damage develops both in type 1 diabetes mellitus (T1DM) and T2DM. Color Doppler ultrasound is widely used for the examination of large- and medium-sized arteries, whereas SPECT and MRI are capable of identifying disturbances in the circulation of microvessels. Former studies using semiquantitative methods showed reduced reactivity and reserve capacity of cerebral vessels in both T1DM and T2DM patients. Our aim was to investigate whether there was any difference in the effects of the 2 types of diabetes mellitus on the global or regional cerebral blood flow, influenced by microvascular damage. Methods: In our study, the circulation and reserve capacity of cerebral arteries was examined using 99mTc-hexamethylpropylene amine oxime SPECT. A total of 17 individuals with T1DM and 43 individuals with T2DM were involved in the study. Results: Both basal and acetazolamide-challenged brain circulation were significantly lower in T2DM patients than in T1DM patients. We did not find a significant difference in the reserve capacity. However, the circulation of the frontal and occipital lobes changed differently in the 2 groups. The ratio of the circulation of the frontal and occipital lobes was significantly reduced both in basal and in acetazolamide-stimulated states in T2DM patients, independently of age (P < 0.0005 and P < 0.017), showing a greater relative decrease in the circulation of the frontal lobe in T2DM patients. Conclusion: There was a significant association between basal brain circulation and age, body mass index, and high-density lipoprotein (HDL), whereas acetazolamide-stimulated circulation showed a significant association with serum triglyceride and HDL.

The effect of metoprolol alone and combined metoprolol–felodipin on the digital microcirculation of patients with primary Raynaud's syndrome

OBJECTIVES Calcium channel inhibitors have beneficial impact on microcirculation, but beta-blocker effect is controversial. Clinicians still do not agree on beta-blocker combination with other treatments in the management of impaired microcirculation. The aim of the present study was to describe the effects of beta-blocker metoprolol monotherapy and combined with calcium channel inhibitor felodipin on digital microcirculation in primary Raynauds syndrome. METHODS We enrolled in this study 46 patients suffering from both hypertension and primary Raynauds syndrome. Fifteen patients were treated with beta-blocker monotherapy (metoprolol), 13 received combined beta-blocker and calcium channel blocker therapy (felodipin and metoprolol), while 18 patients without any medications served as controls. Measurement of digital microcirculation was carried out with laser Doppler scanner. RESULTS AND CONCLUSIONS Our investigation concludes that the concurrent administration of beta-blockers with calcium channel inhibitors positively reduces symptoms in patients suffering from Raynauds syndrome.

In situ macrophage phenotypic transition is affected by altered cellular composition prior to acute sterile muscle injury

The in situ phenotypic switch of macrophages is delayed in acute injury following irradiation. The combination of bone marrow transplantation and local muscle radiation protection allows for the identification of a myeloid cell contribution to tissue repair. PET‐MRI allows monitoring of myeloid cell invasion and metabolism. Altered cellular composition prior to acute sterile injury affects the in situ phenotypic transition of invading myeloid cells to repair macrophages. There is reciprocal intercellular communication between local muscle cell compartments, such as PAX7 positive cells, and recruited macrophages during skeletal muscle regeneration.

A Study on the Basic Criteria for Selecting Heterogeneity Parameters of F18-FDG PET Images

Textural analysis might give new insights into the quantitative characterization of metabolically active tumors. More than thirty textural parameters have been investigated in former F18-FDG studies already. The purpose of the paper is to declare basic requirements as a selection strategy to identify the most appropriate heterogeneity parameters to measure textural features. Our predefined requirements were: a reliable heterogeneity parameter has to be volume independent, reproducible, and suitable for expressing quantitatively the degree of heterogeneity. Based on this criteria, we compared various suggested measures of homogeneity. A homogeneous cylindrical phantom was measured on three different PET/CT scanners using the commonly used protocol. In addition, a custom-made inhomogeneous tumor insert placed into the NEMA image quality phantom was imaged with a set of acquisition times and several different reconstruction protocols. PET data of 65 patients with proven lung lesions were retrospectively analyzed as well. Four heterogeneity parameters out of 27 were found as the most attractive ones to characterize the textural properties of metabolically active tumors in FDG PET images. These four parameters included Entropy, Contrast, Correlation, and Coefficient of Variation. These parameters were independent of delineated tumor volume (bigger than 25–30 ml), provided reproducible values (relative standard deviation< 10%), and showed high sensitivity to changes in heterogeneity. Phantom measurements are a viable way to test the reliability of heterogeneity parameters that would be of interest to nuclear imaging clinicians.

High prevalence of oesophageal involvement in patients with undifferentiated connective tissue disease using radionuclide oesophageal transit scintigraphy.

AimTo look for the frequency of oesophageal dysfunction using radionuclide oesophageal transit scintigraphy in 145 patients with undifferentiated connective tissue disease (UCTD); to seek the correlation between the clinical/laboratory data and scintigraphic alterations; and to determine predictive value of radionuclide oesophageal transit scintigraphy for evolution to established connective tissue disease (CTD). MethodOne hundred and forty-five patients with UCTD were examined by99mTc-DTPA oesophageal transit scintigraphy. The intraoesophageal transport of the radiopharmaceutical was followed and imaged by a gamma camera, a series of 128×128 images were stored and evaluated. The correlation between the scintigraphic data and clinical and laboratory parameters was analysed statistically. ResultsUnequivocally positive scintigraphy, indicative of motor abnormality was found in 46% of patients (66), 71% (47) of whom were totally asymptomatic. Significant correlation was found between the presence and severity of scintigraphic alterations and antinuclear antibodies, the anti-&bgr;2GPI, IgM, IgG, the aCL antibody positivity, and the skin symptoms. Scintigraphic positivity was significantly more frequent in patients evolving to definitive CTD (P=0.0178), and abnormal scan predisposed to transition into the definitive CTD (odds ratio, 2.292; CI, 1.610–4.525). Its cumulative positive predictive value was found to be 43% and cumulative negative predictive value 73% with regard to the development of a definitive CTD. ConclusionOur results show that scintigraphic alterations together with clinical and laboratory alterations can help the clinician in the prediction of final outcome.

The clinical usefulness of the fingers-to-palm ratio in different hand microcirculatory abnormalities.

A non-invasive nuclear medicine technique was developed to screen patients with painful hands so as to separate patients with a normal from those with an abnormal microcirculation of the hands in different clinical conditions. Such a technique is important, as the other methods available are either subjective or rather complicated. The study population consisted of 10 healthy individuals, 23 patients with Raynauds syndrome and 15 patients with mixed connective tissue disease (MCTD). Sixty gamma-camera images of the hands (1 s each) were recorded after a bolus injection of 99Tcm-DTPA via a dorsal foot vein. Regions of interest were drawn on the summed images around the fingers and the palmar region. The fingers-to-palm ratio was then calculated from the total counts inside these regions of interest separately for each hand. The mean fingers-to-palm ratio was 0.94±0.18 (0.71-1.25) for the healthy group, 0.57±0.22 (0.21±1.11) for the MCTD group and 0.40±0.14 (0.18-0.77) for the Raynauds patients. Analysis of variance showed these differences to be highly significant (P<0.001). There were also significant differences between 6 MCTD patients in an active (mean 0.48) and nine patients in an inactive (mean 0.66) clinical state (two-sample t-test: P<0.05). There were no significant differences between the fingers-to-palm ratios of the left and right hands of the same patients (one-sample t-test). Of the 23 primary Raynauds patients, capillary microscopic data were pathological in only eight (34%). We conclude that our method is able to differentiate between patients with normal and those with abnormal microcirculation of the hands. Although measurement of the fingers-to-palm ratio is not a specific method, it is useful both for staging and in the follow-up of patients.

AAZTA: An Ideal Chelating Agent for the Development of 44Sc PET Imaging Agents

Unprecedented fast and efficient complexation of ScIII was demonstrated with the chelating agent AAZTA (AAZTA=1,4-bis(carboxymethyl)-6-[bis(carboxymethyl)]amino-6-methylperhydro-1,4-diazepine) under mild experimental conditions. The robustness of the 44 Sc(AAZTA)- chelate and conjugated biomolecules thereof is further shown by in vivo PET imaging in healthy and tumor mice models. The new results pave the way towards development of efficient Sc-based radiopharmaceuticals using the AAZTA chelator.

Automated lymph node detection and classification on breast and prostate cancer SPECT-CT images

We present a novel detection and classification method to process SPECT-CT images representing breast and prostate lymph nodes. Lymph nodes are those nodes that are near the primer tumor and may become cancerous in time, hence their early detection is a key factor for the successful treatment of the patient. Prior methods focus on the visual aid to manually detect the lymph nodes which still makes the process time-consuming. Other solutions segment the lymph nodes only on CT, where the small lymph nodes may not be located accurately. Our solution processed both SPECT and CT data to provide an accurate classification of all SPECT hot spots. The method has been validated on a huge amount of medical data. Results show that our method is a very effective tool to support physicians working with related images in the field of nuclear medicine.

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

BackgroundThe 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. AimTo develop a non-invasive method suitable for an objective evaluation of the hands circulation to make it possible to use radial arteries safely for the revascularization of coronary arteries. MethodsWe examined 35 patients. After selective compression of the radial and ulnar arteries of both hands, we injected 400 MBq 99mTc-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. ResultsThe 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. ConclusionsHand perfusion with 99mTc-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.