Małgorzata Kobylecka

Inflammatory activity of pericoronary adipose tissue may affect plaque composition in patients with acute coronary syndrome without persistent ST-segment elevation: preliminary results

BACKGROUND The extravascular expression of inflammatory mediators may adversely influence coronary lesion formation and plaque stability through outside-to-inside signalling. It has been shown that the maximal standardised uptake value (SUV) of 18-fluorodeoxyglucose detected by positron emission tomography (PET/CT) is proportional to macrophage density. AIM To investigate whether the inflammatory activity of pericoronary adipose tissue (PVAT) may influence plaque composition in acute coronary syndrome without persistent ST-segment elevation (NSTE-ACS) patients. METHODS In a prospective study, 36 coronary arteries (LM, RCA, LCX, LAD) were investigated in non-diabetic patients with a low or intermediate risk of NSTE-ACS (GRACE ≤ 140). SUV was measured in fat surrounding coronary arteries on the sections corresponding to proximal and medial segments (Siemens biograph 64-PET/CT system). Additionally, SUV was measured in subcutaneous fat (SC), visceral thoracic fat (VS), and epicardial fat over the right ventricle (EPI). Virtual histology intravascular ultrasound (VH-IVUS) was performed to assess plaque composition (Volcano, USA). PET/CT sections were further examined in segments corresponding to coronary plaques. RESULTS PVAT SUV in NSTE-ACS patients was significantly greater than in other fat locations (LM SUV: 1.60; RCA SUV: 1.54; LCX SUV: 1.94; LAD SUV: 2.37 vs. SC SUV 0.57; VS SUV: 0.77; EPI SUV: 0.98; p < 0.001; ANOVA). PVAT SUV positively correlated with plaque burden (r = 0.49, p < 0.05) and necrotic core plaque rate (r = 0.68, p < 0.05), and negatively correlated with fibrous plaque rate (r = -0.52, p < 0.05). CONCLUSIONS The inflammatory activity of PVAT reflected by SUV is greater than in subcutaneous, visceral thoracic, or epicardial tissue in NSTE-ACS patients; PVAT SUV correlates with the plaque burden and necrotic core component of coronary plaque.

Myocardial viability assessment in 18FDG PET/CT study (18FDG PET myocardial viability assessment).

Accurate identification of viable myocardium is crucial in patient qualification for medical or surgical treatment. Only persons with confirmed cardiac viability will benefit from revascularization procedures. It is also well known, that the amount of viable myocardium assessed preoperatively is the best indicator of long term cardiac event free survival after cardiac intervention.There are several diagnostic approaches used in current clinical practice for assessment of myocardial viability. Analysis of wall thickness or myocardial contraction, evaluation of cardiac perfusion or metabolism can be assessed using following modalities: Echocardiography, Cardiac Molecular Imaging techniques (PET, SPECT), Cardiovascular MR or Cardiovascular CT. The article describes the methods and problems of viability assessment in 18FDG PET study. PET imaging has proved its accuracy and reproducibility for myocardial ischemia and viability assessment. However this unique in its ability for showing the particular substrate metabolism technique has unfortunately some disadvantages: currently achieved PET resolution is 0.4 cm. However the combined devices multislice computed tomography scanners with PET (PET/CT) are now widely used in clinical practice. This combination allows for wider morphologic assessments: coronary calcium scoring and non-invasive coronary angiography may be added to myocardial perfusion/metabolic imaging if necessary.

Evaluation of T-wave alternans in high-resolution ECG maps recorded during the stress test in patients after myocardial infarction

Introduction Recent studies point to analysis of T-wave alternans as a promising indicator of an increased risk of life-threatening ventricular arrhythmias. In this study the occurrence of T-wave alternans in the high-resolution ECGs recorded during the exercise stress test and scintigraphic tests (SPECT) in patients with ischemic heart disease was examined. Material and methods The study group consisted of 33 patients after myocardial infarction. In the group of patients after myocardial infarction and with low left ventricular ejection fraction correlations of 70% between the test results of T-wave alternans and SPECT and 60% between the test results of T-wave alternans and stress test were found. Results In the group of patients after myocardial infarction but with high left ventricular ejection fraction correlations were respectively 39% and 48%. The analysis of the electrocardiographic maps showed a strong dependence of this correlation on the T-wave alternans amplitude and location of the ECG measuring electrode on the chest. The results might suggest that in patients after myocardial infarction and at increased risk for sudden cardiac death T-wave alternans may also provide information about cardiac electrical instability associated with ischemia. Conclusions It can also be assumed that the position of the electrode where the highest level of the T-wave alternans was detected can indicate the location of the ischemic region of the heart.

Radionuclide synovectomy – essentials for rheumatologists

Radionuclide synovectomy is a minimally invasive method of treating persistent joint inflammation. It involves intra-articular injection of radioactive colloids which induce necrosis and fibrosis of hypertrophic synovial membrane. The most common indication for radiosynovectomy is rheumatoid arthritis, although patients with seronegative spondyloarthropathies, unclassified arthritis, haemophilic arthropathy and other less common arthropathies can also benefit from this method. Radiosynovectomy is safe, well tolerated and efficacious. About 70–80% of patients respond well to the therapy. However, the therapeutic effects are considerably worse in patients with co-existent osteoarthritis and advanced joint degeneration. Despite its advantages, radionuclide synovectomy is not performed as often as it could be, so greater knowledge and understanding of this method are needed. The authors present the most important facts about radiosynovectomy that may help rheumatologists in their daily clinical practice.

Simplified protocol of cardiac 18F-fluorodeoxyglucose positron emission tomography viability study in normoglycemic patients with known coronary artery disease ☆

PURPOSE The purpose was to evaluate quality of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) myocardial scans and its correlation with background glucose (BG) after simplified 5% intravenous glucose load protocol. METHODS An intravenous glucose load protocol was applied in 69 normoglycemic patients with confirmed coronary artery disease. The blood glucose level was measured every 15 min. RESULTS Eighty-four percent of images were optimal, 8.7% suboptimal, and 7.3% uninterpretable. The quality of 18F-FDG-PET was BG independent and body mass index dependent (P=.0007). CONCLUSIONS Simplified glucose load protocol is a safe and efficient method of preparation for FDG cardiac viability study in patients with normoglycemia.

Microvascular Obstruction Evaluation Using Cardiovascular Magnetic Resonance (CMR) in ST-Elevated Myocardial Infarction (STEMI) Patients

Summary Backround Restoration of blood flow in epicardial coronary artery in patients with acute myocardial infarction can, but does not have to restore efficient blood flow in coronary circulation. The aim of the study was a direct comparison of microvascular obstruction (MVO) detected by rest and stress perfusion imaging and gadolinium enhancement obtained 2 min. (early MVO) and 15 min. (delayed MVO) post contrast. Material/Methods 106 patients with first anterior myocardial infarction were studied. Cardiovascular magnetic resonance (CMR) was performed 5±2 days after primary percutaneous coronary intervention (pPCI). Stress and rest perfusion imaging was performed as well as early and delayed gadolinium enhancement and systolic function assessment. Scoring of segmental function, perfusion defect, MVO and scar transmurality was performed in 16 segment left ventricular model. Results The prevalence of MVO varies significantly between imaging techniques ranging from 48.8% for delayed MVO to 94% with stress perfusion. Median sum of scores was significantly different for each technique: stress perfusion 13 (7; 18), rest perfusion 3 (0.5; 6), early MVO 3 (0; 8), delayed MVO 0 (0; 4); p<0.05. Infarct size, stress and rest perfusion defects were independent predictors of LV EF at discharge from hospital. Conclusions Imaging protocol has a significant impact on MVO results. The study is the first to describe a stress-induced MVO in STEMI patients. Further research is needed to evaluate its impact on a long term prognosis.

ST-segment changes in high-resolution body surface potential maps measured during exercise to assess myocardial ischemia: a pilot study.

Introduction The aim of the study was to assess myocardial ischemia by analysis of ST-segment changes in high-resolution body surface potential maps (HR-BSPM) measured at rest and during an exercise stress test. Material and methods The study was carried out on a group of 28 patients with stable coronary artery disease and 15 healthy volunteers. The HR-BSPM were measured at rest and during the exercise stress test on a supine ergometer. The workload was increased in stages by 25 W every 2 min, beginning at 50 W. The maps of ST-segment depression (ST60) were calculated from time averaged recordings at rest and at maximal workload. Results The efficiency in detection of myocardial ischemia was higher for HR-BSPM than for standard 12-lead electrocardiography (ECG) when both methods were evaluated by outcomes of coronarography. The sensitivity of HR-BSPM was 82.4% while for the standard 12-lead ECG exercise stress test it was 58.8%. For some patients significant changes in the ST segment were observed at stress HR-BSPM but were not visible in standard 12-lead ECG recorded under the same conditions. Conclusions Obtained high values of sensitivity and specificity in myocardial ischemia detection suggest that maps of ST60 calculated from HR-BSPM can improve detection of patients with ischemic heart disease in comparison to the standard electrocardiographic exercise stress test examinations.

SHOULD WE BE CONCERNED ABOUT THE DOSES OF IONIZING RADIATION RELATED TO DIAGNOSTIC AND FOLLOW-UP IMAGING IN PATIENTS WITH SOLITARY PULMONARY NODULES?

Diagnosing solitary pulmonary nodules (SPNs) frequently requires radiological follow up associated with exposure to ionizing radiation. The aim of this study was to estimate the effective dose of ionizing radiation in patients diagnosed and followed up due to SPNs, which were found beyond lung cancer screening programs. We estimated the exposure to ionizing radiation as effective doses (ED) of all imaging techniques using ionizing radiation: chest computed tomography (CT), contrast enhanced CT (CECT) and positron emission tomography combined with CT (PET/CT) in each patient. The median ED related to CT, CECT and PET/CT were 27.8, 17.2 and 20.4 mSv, respectively. The total ED related to all imaging examinations performed during 2 years of radiological follow-up was 33.9 mSv (range: 3.2-122.4) per patient. Majority (59%) of radiation exposure resulted from repeated chest CT. In conclusion, diagnosis and follow up of patients with SPN with different radiological techniques is associated with high exposure to ionizing radiation.

Radionuclide imaging and therapy in a patient with coexistent diabetic foot syndrome and psoriatic arthritis

We report a case of 67-year-old man suffering from psoriatic arthritis, type 2 diabetes and diabetic foot syndrome. The patient presented symptoms of inflammation of the right ankle joint. Scintigraphic imaging with radiolabeled white blood cells was performed to differentiate whether the inflammation was related to psoriatic arthritis or diabetic foot syndrome. After revealing that, the inflammatory process was restricted only to the articular space of subtalar joint, the patient was diagnosed with exacerbation of psoriatic arthritis and qualified for radionuclide synovectomy. In patients with coexistent diabetic foot syndrome and inflammatory arthritis of the foot it is of vital importance to accurately differentiate these two conditions. We conclude that this can be potentially achieved with radiolabeled white blood cells scintigraphic imaging.

Assessment of the myocardial FDG-PET image quality with the use of maximal Standardized Uptake Value myocardial to background index. Application of the results in regard to semiquantitative assessment of myocardial viability with cardiac dedicated softwar

BACKGROUND The objective of this study was to semiquantitatively assess the degree of myocardial fluorodeoxyglucose (FDG) uptake in glucose-loaded myocardial viability positron emission tomography/computed tomography (PET/CT) scans, to calculate the myocardial to background index, and correlate the index with image quality assessed on the basis of visual qualitative assessment. MATERIAL AND METHODS The myocardial FDG-PET/CT study was carried out in 69 non-diabetic patients, who had known coronary artery disease, by intravenous injection of 250 ± 70 MBq (range: 180-320 MBq) FDG. Images were interpreted visually and patients were divided into three groups according to the grade of myocardial uptake: optimal, suboptimal, and uninterpretable. Semiquantitative analysis was performed by calculating the standardized uptake value (SUVmax) for myocardium and background (blood pool) activity, and expressed as the myocardial to background (M/B) activity ratio. RESULTS On the basis of visual (qualitative) analysis, 60/69 (86.96%) patients showed optimal quality of FDG cardiac uptake, 3/69 (4.35%) were suboptimal, and uninterpretable FDG PET scan results were found in 6/69 (8.70%) patients. The M/B index was found to be significantly higher in images of optimal vs. suboptimal quality (6.87 ± 3.99 vs. 1.65 ± 0.78 respectively; p < 0.0001). CONCLUSIONS The index ratio of 2.2, which is consistent with the upper borderline value for visually uninterpretable images, was considered the cut-off value for scans of optimal and non-optimal quality.