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.

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.

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.

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.

Different technical possibilities of post-therapeutic tandem 90Y/ /177Lu-DOTATATE imaging.

BACKGROUND: Neuroendocrine tumors (NETs) are a heterogeneous group of neoplasms derived from endocrine stem cells.These tumors are characterized by overexpression of somatostatin receptors (SSTR), which is utilized for imaging using SSTR analogs. Peptide receptor radionuclide therapy (PRRT) somatostatin analogs labeled with 90Y and 177Lu in neuroendocrine tumors (NETs) results in symptomatic improvement, prolonged survival,and enhanced quality of life. The post-therapeutic imaging leadsto possibility of biodistribution of therapy. The aim of our study was to describe different possibilities of post-therapeutic imaging in patients underwent tandem therapy 90Y/177Lu-DOTATATE with preliminary results of 90Y PET imaging. MATERIAL AND METHODS: Thirty patients (11 men, 19 women; the mean age 55 ± 10.9 y) with histological confirmation of metastatic neuroendocrine tumors (G1 and G2) were treated with tandem therapy 90Y/177Lu-DOTATATE. WHBA scan and SPECT acquisition of the abdomen were performed 24 hours post therapy injection, on the dual-head Varicam camera (ELSCINT) using 177Lu photopeak and 90Y bremsstrahlung. PET imaging of 90Y component was done on Siemens Biograph Truepoint PET/CT (window 511 keV ± 15%)4 hours after 90Y/177Lu-DOTATATE. Additionally phantom studies were performer to analyze the spatial resolution of different protocols. RESULTS: Out of all the patients, median OS was 49.8 months and median EFS time 24.3 months. Spatial resolution achieved for 90Y, 177 Lu and PET imaging of 90Y component measured using the phantom of the torso filled up with water was 20 mm, 8 mm and 4-5 mm FWHM, respectively. Spatial resolution in human body in our study was about 30 mm for 90Y, 15 mm for 177Lu and 25-30 mm for PET imaging of 90Y component. CONCLUSIONS: The theoretically best spatial resolution offers PET scanner, however it is important to keep in mind that 90Y-imaging PET is not used for diagnosis purposes (small activities)but rather to present new possibility of post-therapeutic imaging (substantially higher activities). For post-therapeutic imaging after intravenous radiopharmaceutical administration the best spatial resolution offers standard scintigraphic camera for 90Y/177Lu DOTATATE imaging, with using 177Lu photopeaks. The worst spatial resolution offers standard scintigraphic camera for 90Y/177Lu DOTATATE imaging, with using 90Y bremsstrahlung gammas.