Positron emission tomography in clinically suspected myocarditis - STREAM study design.

AIM: Myocarditis is an inflammatory disease associated with increased glucose uptake. The hypothesis of this study assumes that 18F-2-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT) may improve specificity and sensitivity in the diagnosis of myocarditis and referral for endomyocardial biopsy (EMB), adding additional information for post-discharge risk stratification. The aim of the study is to assess the diagnostic and prognostic feasibility of FDG-PET/CT in comparison to cardiac magnetic resonance (CMR) (alone or in combination) in patients with clinically suspected myocarditis undergoing EMB. METHODS: Fifty hospitalized patients with clinically suspected myocarditis who meet the inclusion/exclusion criteria will be enrolled in a prospective, observational, multicentre, cohort study (NCT04085718). The primary endpoint is the sensitivity and specificity of FDG-PET/CT imaging in the diagnosis of myocarditis. The main secondary endpoints include correlation of FDG-PET/CT imaging with CMR, echocardiography, and EMB results. The patients will undergo the following evaluations: clinical examination, blood tests (including biomarkers of fibrosis and anti-heart autoantibodies (AHA)), ECG, 24 h Holter ECG, echocardiography, CMR, as well as resting single photon emission computed tomography (SPECT) to assess possible myocardial perfusion defects, cardiac FDG-PET/CT and right ventricular EMB. After 6-months a follow-up visit will be performed (including 24 h Holter ECG, echocardiography and CMR). Investigators evaluating individual studies (CMR, SPECT, FDG-PET/CT and EMB) are to be blinded to the other tests' results. CONCLUSION: We believe that FDG-PET/CT alone or in combination with CMR may be a useful tool for improving diagnostic accuracy in patients with clinically suspected myocarditis.

Radioiodine therapy and Graves' disease - Myths and reality.

INTRODUCTION: Autoimmune reactions in Graves' disease (GD) occur not only in the thyroid gland, but also in the orbital connective tissue, eyelids, extraocular muscles. The occurrence of orbitopathy in the course of GD is influenced by environmental factors, e.g. cigarette smoking. OBJECTIVES: The aim of the study was to analyze the effect of cigarette smoking on the efficacy of activity of radioiodine(131I) therapy in patients with GD. We also studied the influence of cigarette smoking and the efficacy of prednisone prophylaxis on the risk of thyroid-associated ophthalmopathy (TAO) development after radioiodine therapy (RIT) during two years of follow-up. PATIENTS AND METHODS: Medical records of hyperthyroid patients treated with radioiodine had been included. Patients were scheduled to visit outpatient clinics at baseline and 1, 3, 6, 9, 12, 18, and 24 months after RIT. RESULTS: The studied group consisted of 336 patients (274 women, 62 men) diagnosed with GD and treated with RIT; 130 patients received second therapeutic dose of 131I due to recurrent hyperthyroidism. Among all studied patients, 220 (65.5%) were smokers and 116 (34.5%) non-smokers. In the group of smokers 115 (52.2%) of patients received single RIT, 105 (47.8%) received second dose of RAI due to recurrent hyperthyroidism. In non-smokers 91 (78.6%) received single activity of RAI, while 25 (21.4%) patients required second RIT due to recurrent hyperthyroidism. The ophthalmic symptoms in the group of smokers after RIT were less frequent, if the patient received preventative treatment in the form of oral prednisone (P = 0.0088). CONCLUSIONS: The results of our study suggest that cigarette smoking reduces the efficacy of treatment with 131I in patients with GD. The study also confirmed the effectiveness of steroid prophylaxis against TAO development or exacerbation after RIT.

Optimal ECG Lead System for Exercise Assessment of Ischemic Heart Disease.

The diagnostic value of an ECG exercise test in diagnosis of ischemic heart disease (IHD) is limited. We investigated whether it is possible to develop a method for diagnosis of IHD which uses a low number of optimal ECG leads and has a higher diagnostic efficiency than conventional exercise ECG. This study was carried out on 43 patients. The 67-lead high-resolution ECG was recorded at rest and during exercise. The diagnostic value of ST segment depression (ΔST60) and T-wave morphology change (δT) determined in optimized ECG lead configurations was higher than for the standard 12-lead ECG. The best results were obtained for δT determined from 6 ECG electrode locations where sensitivity and specificity were 70% and 69% whereas for the standard exercise ECG were 63% and 62%, respectively. The small number of ECG leads used allows for easy hardware implementation of the methods for use in clinical settings.

Determination of left ventricular ejection fraction by gated 99mTc-MIBI G-SPECT in patients with takotsubo syndrome - comparison with echocardiography.

BACKGROUND: Echocardiography is the first exam to establish the myocardial function in patients with takotsubo syndrome (TTS). However, ECG-Gated Myocardial Single-Photon Emission Tomography (G-SPECT) also allows to calculate left ventricular ejection fraction (LVEF) and can be useful in early stadium of TTS. AIM: To compare LVEF obtained from 99mTc-MIBI G-SPECT and echocardiography in patients with TTS. MATERIAL AND METHODS: Study population:20 patients in medium age 77(62-89) with TTS were included. In all patients 99mTc-MIBI G-SPECT and echocardiography was performed on the same day. RESULTS: LVEF measured by G-SPECT and echocardiography ranged from 34 to 83% and 38 to 69%, respectively. The LVEF values for ECHO were significantly lower than for SPECT. The correlation between the LVEF was r = 0.76. The calculated correlation coefficient (r) for linear regression analysis was 0.64. The following equation shows the approximate interdependence of both LVEF calculations: LVEF GSPECT = 10.35 + 0.93 * LVEF Echo. CONCLUSIONS: G-SPECT tends to overerestimate LVEF compared to echocardiography so these imaging techniques should not be used interchangeably. Calculated equation should be used for comparison of LVEF.

Relationship between parathyroid gland scintigraphy and its histopathology, oxyphil cell content and volume: a retrospective study.

BACKGROUND: Mechanisms that are responsible for positive 99mTc-MIBI uptake in parathyroid glands are not clearly understood, some authors suggest there is a correlation between 99mTc MIBI accumulation and oxyphil cell content or parathyroid gland volume. The aim of our work was to assess the relationship between the pathological structure of parathyroids, their volume, oxyphil cell content and parathyroid 99mTc-MIBI retention. MATERIAL AND METHODS: A total of 62 hyperfunctioning parathyroid glands in 46 patients were retrospectively analyzed. Preoperative 99mTc-MIBI scintigraphy was performed according to the double-phase and subtraction protocol. After surgery all glands were evaluated histologically, oxyphil cell content was assessed and volume of each excised gland was calculated. RESULTS: Scintigraphy was positive in 41 of 62 parathyroid glands (66%). The median volume of positive glands was larger than that of negative glands (1.33 ml vs 0.7 ml, p = 0.015). Of the parathyroid lesions, there were 14 (22.6%) cases of nodular hyperplasia, 23 (37.1%) cases of diffuse hyperplasia, and 25 (40.3%) cases of adenomas. A high (≥ 25%) oxyphil cell content was found in 16 glands (25.8%) and a low ( < 25%) oxyphil cell content in 46 (74.2%) glands. Histopathology of parathyroid glands was related to the scintigraphy result (p = 0.002), but not to the 99mTc-MIBI uptake pattern (p = 0.868). The overall result of scintigraphy was not related to the oxyphil cell content (p = 0.797). 99mTc-MIBI uptake pattern wasn't related to the oxyphil cell content (p = 0.833). In general, parathyroid lesions with low oxyphil cell content were larger than parathyroid glands with high oxyphil cell content (1.33 ml vs 0.5 ml, respectively; p = 0.01). The median volume of parathyroids containing a high number of oxyphil cells and having a prolonged 99mTc-MIBI retention was larger than those without prolonged 99mTc-MIBI retention (1.62 ml vs 0.3 ml, respectively; p = 0.008). The median volume of parathyroids with low oxyphil cells content and showing prolonged 99mTc-MIBI retention was larger than those without prolonged 99mTc-MIBI retention (1.95 ml vs 1.07 ml, respectively; p = 0.014). CONCLUSIONS: Our findings suggest that a positive scintigraphy result depends on parathyroid histopathology and gland volume and does not depend on the presence of oxyphil cells. Prolonged 99mTc-retention is not related to the parathyroid gland histopathology and the presence of oxyphil cells but to the gland volume.

Diagnostic utility of hybrid single photon emission computed tomography/computed tomography imaging in patients with Takotsubo syndrome.

PURPOSE: Clinical symptoms and electrocardiographic changes in patients with Takotsubo syndrome can be similar to patients with myocardial infarction. The aim of the study was to assess the impact of SPECT/CT imaging on the diagnosis and management of Takotsubo syndrome (TTS). METHODS: Gated single photon emission computed tomography (SPECT)/CT after injection 99Tc-MIBI in resting conditions was performed in 27 patients with TTS using dual-head Symbia T6SPECT/CT hybrid device. CT data were used for attenuation correction of SPECT images and to assess the risk of coronary artery disease on the basis of coronary artery calcium score. RESULTS: Abnormal myocardial perfusion was found in 20/27 patients. The mean defect size was 9.8 cm, the extent 11.7%, mean total perfusion defect was 10.36%, mean summed rest score (SRS) 6.71.Left ventricle ejection fraction was lower in patients with SRS at least 4 than in patients with SRS less than 4. Perfusion defect size, total perfusion defect, number of akinetic segments in echocardiography and number of segments with perfusion defect in SPECT were higher in the group with SRS at least 4. The applied attenuation correction algorithms did not change the result of our SPECT study. CONCLUSION: In the majority of patients with TTS perfusion in SPECT was normal or only minor perfusion defect was observed. Application of CT attenuation correction did not change the final result of myocardial perfusion imaging; therefore, the CT component of the SPECT/CT study performed for attenuation correction is not useful for TTS diagnosis.

High-Resolution Body Surface Potential Mapping in Exercise Assessment of Ischemic Heart Disease.

Standard 12-lead ECG exercise testing is commonly used for screening of ischemic heart disease (IHD). We studied if high-resolution body surface potential mapping (HR-BSPM) during exercise offers advantages over current standards in noninvasive evaluation of IHD. This study was carried out on 90 IHD patients and 33 healthy controls. The 67-lead HR-BSPM was recorded at rest and during exercise. Twenty-one ECG parameters including classical ST criteria were compared. The effectiveness of methods was verified based on the results of SPECT and coronary angiography. The most effective parameters in the diagnosis of IHD were: amplitude parameter ΔST60 and δT parameter showing T-wave morphology changes during exercise. The sensitivities/specificities of ΔST60 and δT parameters for the HR-BSPM were 70/69 and 59/62%, while for the standard 12-lead ECG system they were: 63/62 and 59/56%. These results demonstrate the usefulness of HR-BSPM measurements during exercise. HR-BSPM resulted in higher sensitivities and specificities compared to the standard 12-lead exercise test. The advantage was partially associated with observed ischemic changes outside standard precordial leads position that were not visible when using the standard 12-lead exercise test. This justifies research into the optimization of the number and position of ECG leads in exercise testing.

Takotsubo cardiomyopathy: FDG myocardial uptake pattern in fasting patients. Comparison of PET/CT, SPECT, and ECHO results.

BACKGROUND: The aim of this study was to assess the accumulation pattern of 18F-FDG in fasting patients with takotsubo cardiomyopathy (TTC) and to correlate the results with perfusion scintigraphy and echocardiography. METHODS: 18 consecutive patients with TTC were identified by clinical symptoms, cardiac catheterization, and echocardiography. Coronary angiography (CA) and transthoracic echocardiography (TTE) were performed on the day of the onset of symptoms. An assessment of myocardial perfusion (99mTc-MIBI) and glucose metabolism (18F-FDG) was performed within 18 days. RESULTS: SPECT showed no regional perfusion abnormalities in 10/18 patients, and a mild perfusion defect was found in 8/18 patients. Perfusion abnormalities were limited to apical and para-apical regions. In 8/18 cases, there was an increased selective apical 18F-FDG accumulation. In 10/18 cases, in spite of the fastened 18F-FDG protocol, slightly inhomogeneous 18F-FDG uptake was present in the entire myocardium: with relatively reduced uptake of 18F-FDG in the apical region and LV mid-segments. CONCLUSION: This study demonstrated the heterogeneous nature of myocardial 18F-FDG accumulation in patients with TTC. Selective, preferential apical 18F-FDG uptake in almost half of the patients confirms an existing disorder of glucose metabolism, similar to that observed in stunned or hibernated myocardium.

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.

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.

Comparison of scintigraphy and ultrasound imaging in patients with primary, secondary and tertiary hyperparathyroidism - own experience.

BACKGROUND: The imaging techniques most commonly used in the diagnosis of hyperparathyroidisms are ultrasound and scintigraphy. The diagnostic algorithms vary, depending mainly on the population, and experience of physicians. AIM: Aim of the present research was to determine the usefulness of parathyroid scintigraphy and ultrasonography in patients diagnosed for hyperparathyroidism in own material. MATERIAL AND METHOD: In the present research, 96 operated patients with documented primary, secondary and tertiary hyperparathyroidism were retrospectively analyzed. All patients underwent a 99mTc hexakis-2-methoxyisobutylisonitrile scintigraphy of the neck with the use of subtraction and two-phase examinations. Ultrasonography of the neck was performed in all the patients in B mode 2D presentation. A total number of 172 parathyroid glands were analyzed. RESULTS: The sensitivity and specificity of scintigraphy was 68% and 60%, respectively. The sensitivity of ultrasound was 49% and specificity 85%. Both techniques allowed visualization of 76 parathyroid glands. Ultrasound revealed 19 glands that were not visible in scintigraphy. Scintigraphy showed 76 parathyroid glands that were not visualized on ultrasound. Having combined the results of scintigraphy and ultrasound, the sensitivity of 76% and specificity of 50% were obtained. Considering the ability to locate the parathyroid glands in both techniques as a positive result, the sensitivity decreased to 37% and specificity rose to 95%. CONCLUSIONS: Scintigraphy showed greater sensitivity than ultrasound in the localization of enlarged parathyroid glands. Ultrasound, in turn, was characterized by a higher specificity. The combined use of scintigraphy and ultrasonography allowed to obtain the specificity of 95%. In the light of obtained results, scintigraphy and ultrasonography are complementary and should be used together.

PET/CT evaluation of 18F-FDG uptake in pericoronary adipose tissue in patients with stable coronary artery disease: Independent predictor of atherosclerotic lesions' formation?

BACKGROUND: Inflammatory infiltrations in EAT which releases inflammatory cytokines correspond anatomically to the atheromatous plaques in underlying coronary vessels. However, it is unknown whether inflammatory activity of pericoronary adipose tissue (PCAT) promotes coronary atherosclerosis. METHODS AND RESULTS: 35 non-diabetic patients with confirmed CAD and 35 non-CAD controls matched for age and BMI underwent 18F-FDG-PET/CT. Maximal SUV normalized by LA blood activity was measured on the sections corresponding to the respective coronaries (RCA, LCX, LAD), as well, as in subcutaneous fat, visceral fat, and epicardial fat. Extent of CAD was determined by % stenosis in segments corresponding to 18F-FDG-PET/CT sections in coronarography using quantitative coronary analysis. PCAT SUV was significantly greater than SUV in other fat locations, as well as PCAT SUV in the controls. In CAD patients with BMI >25, PCAT SUV was positively related to % stenosis of a respective coronary artery (RCA: 0.43; P < .05; LCX 0.58; P < .05; LAD 0.65; P < .05). PCAT SUV was the only independent predictor of coronary stenosis of LAD and RCA. CONCLUSIONS: Inflammatory activity of PCAT is greater than in other fat locations, in CAD is greater than in non-CAD controls, and is independently associated with coronary stenosis. In overweight patients, PCAT SUV correlates with the extent of CAD.

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.

Esophageal transit scintigraphy in systemic sclerosis.

Systemic sclerosis is a rare connective tissue disease, distinctive features of which are fibrosis and microangiopathy. The esophagus is one of the most commonly involved internal organs. Most patients experience dysphagia, difficulties in swallowing and gastro-esophageal reflux. However, in up to one third of cases, the initial onset of esophageal disease may be clinically silent. There are several diagnostic modalities available for assessing both morphological and functional abnormalities of the esophagus. If structural abnormalities are suspected, endoscopy is the method of choice. Functional evaluation is best achieved with manometry. Both endoscopy and manometry are invasive techniques, with low patient acceptance. Barium-contrast study is well tolerated, but qualitative assessment of functional abnormalities is imprecise. Esophageal scintigraphy is an easy, non-invasive, sensitive and specific diagnostic modality. It can detect esophageal dysfunction even in asymptomatic patients. In patients already diagnosed with systemic sclerosis, scintigraphy is useful in evaluating severity and progression of the disease.

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.

Computer program for analysis of parathyroid scintigraphy examinations: combination of dual-tracer (subtraction) and double phase single-tracer washout techniques.

There is no controversy in the published literature that sensitivity and specificity of parathyroid scintigraphy is superior to other imaging techniques. However no uniform protocol has been established for scintigraphy. In order to analyze parathyroid scintigraphic images in the Department of Nuclear Medicine at the Medical University of Warsaw we have developed a program that allows qualitative and quantitative evaluation of recorded images and motion artifacts correction. This program offers a uniform procedure of analysis of parathyroid imaging results in diagnostic centers, accelerates the analysis of parathyroid tests performed with use of single radioactive tracer, that require the acquisition of consecutive images of the patient, without altering his body position between successive stages of registration. This program allows for automation of previously time consuming procedures and thus saves time and decreases a risk of operator's errors.