Extinction of Lipomatous Hypertrophy of the Interatrial Septum FDG Uptake With Propranolol Premedication.

ABSTRACT: Lipomatous hypertrophy of the interatrial septum is a rare lesion of the heart. CT and cardiac MR are often sufficient to determine the benign lipomatous nature of the tumor and can avoid the need for histological confirmation. Lipomatous hypertrophy of the interatrial septum contains variable amounts of brown adipose tissue, resulting in different degrees of 18 F-FDG uptake in PET. We report the case of a patient with an interatrial lesion suspected of malignancy, discovered on CT and failing cardiac MR, with initial 18 F-FDG uptake. Final characterization was made thanks to 18 F-FDG PET with ß-blocker premedication, avoiding an invasive procedure.

Precision of Myocardial Blood Flow and Flow Reserve Measurement During CZT SPECT Perfusion Imaging Processing: Intra- and Interobserver Variability.

The aim of this study was to evaluate the reproducibility of myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurement in patients referred for dynamic SPECT. Methods: We retrospectively analyzed patients referred for myocardial perfusion imaging. SPECT data were acquired on a cadmium zinc telluride-based pinhole cardiac camera in list mode using a stress (251 ± 15 MBq)/rest (512 ± 26 MBq) 1-d 99mTc-tetrofosmin protocol. Kinetic analyses were done with software using a 1-tissue-compartment model and converted to MBF using a previously determined extraction fraction correction. MFR was analyzed and compared globally and regionally. Motion detection was applied, but not attenuation correction. Results: In total, 124 patients (64 male, 60 female) were included, and SPECT acquisitions were twice reconstructed by the same nuclear medicine board-certified physician for 50 patients and by 2 different physicians for 74. Both intra- and interobserver measurements of global MFR had no significant bias (-0.01 [P = 0.94] and 0.01 [P = 0.67], respectively). However, rest MBF and stress MBF were significantly different in global left ventricular evaluation (P = 0.001 and P = 0.002, respectively) and in the anterior territory (P < 0.0001) on interuser analysis. The average coefficient of variation was 15%-30% of the mean stress MBF if the analysis was performed by the same physician or 2 different physicians and was around 20% of the mean MFR independently of the processing physician. Using the MFR threshold of 2, we noticed good intrauser agreement, whereas it was moderate when the users were different (κ = 0.75 [95% CI, 0.56-0.94] vs. 0.56 [95% CI, 0.36-0.75], respectively). Conclusion: Repeated measurements of global MFR by the same physician or 2 different physicians were similar, with an average coefficient of variation of 20%. Better reproducibility was achieved for intrauser MBF evaluation. Automation of processing is needed to improve reproducibility.

18 F-FDG Muscular Uptake in Statin-Associated Symptoms Without Myositis : How Long to Stop Treatment for Image Quality Improvement?

ABSTRACT: Statin-associated muscle symptoms are a frequent adverse effect of statin treatment and can lead to a statin-associated myopathy characterized by a significant serum creatine kinase increase. We report the case of an 80-year-old man who presented an increased muscular 18 F-FDG uptake in a statin-associated muscle symptom without creatine kinase abnormality or inflammation. Statin treatment was discontinued for 6 hours, 3 days, and 7 days on consecutive follow-up examinations. The 1-week window clearly enhanced image quality. This case illustrates the possibility of diffuse muscular 18 F-FDG uptake without myositis and the need for a minimal 1-week statin discontinuation to reduce muscular uptake.

Gated Tomographic Radionuclide Angiography Using 3D-Ring CZT StarGuide SPECT/CT Head-To-Head Comparison With a Cardiac-Dedicated CZT Camera: First Clinical Use and Validation.

ABSTRACT: Gated tomographic radionuclide angiography can assess and monitor left cardiac function. Dedicated cardiac CZT cameras have enabled dose reduction and quicker acquisitions. New 3D-ring CZT general purpose systems are now available. We report 50 patients who underwent a 7-minute acquisition on a cardiac-dedicated CZT camera and 9 minutes on a new 3D-ring CZT system after mean injection of 321.4 ± 55.9 MBq 99mTc-labelled human serum albumin. There was no significant difference in left ventricular volumes, and left and right ventricular ejection fractions. These preliminary results seem to validate the use of 3D-ring CZT system for LEVF and cardiac function evaluation.

Regadenoson versus dipyridamole: Evaluation of stress myocardial blood flow response on a CZT-SPECT camera.

BACKGROUND: Regadenoson is a selective adenosine receptor agonist. It is currently unclear if the level of hyperemia differs between stress agents. We compared Myocardial Blood Flow (MBF) and Myocardial Flow Reserve (MFR) response on CZT-SPECT Myocardial Perfusion Imaging (MPI) to evaluate if dipyridamole and regadenoson could induce the same level of hyperemia. METHODS: 228 patients with dynamic CZT-SPECT MPI were retrospectively analyzed (66 patients stressed with regadenoson and 162 with dipyridamole) in terms of MBF and MFR. To rule out confounding factors, two groups of 41 patients were matched for clinical characteristics in a sub-analysis, excluding high cardiovascular risk patients. RESULTS: Overall stress MBF was higher in regadenoson patients (1.71 ± 0.73 vs. 1.44 ± 0.55 mL·min-1·g-1 for regadenoson and dipyridamole, respectively, p < .05). However, when confounding factors were ruled out, stress MBF (1.57 ± 0.56 vs. 1.61 ± 0.62 mL·min-1·g-1 for dipyridamole and regadenoson, respectively, p = .88) and MFR (2.62 ± 0.77 vs. 2.46 ± 0.76 for dipyridamole and regadenoson, respectively, p = .40) were not different between regadenoson and dipyridamole. CONCLUSIONS: Our results suggest that dipyridamole and regadenoson induce equivalent hyperemia in dynamic SPECT with similar stress MBF and MFR in comparable patients.

Myocardial Flow Reserve Measurement During CZT-SPECT Perfusion Imaging for Coronary Artery Disease Screening: Correlation With Clinical Findings and Invasive Coronary Angiography-The CFR-OR Study.

Purpose: The aim of this study was to assess the results of cadmium zinc telluride (CZT)- single-photon emission computed tomography (SPECT) myocardial flow reserve (MFR) in coronary artery disease (CAD) screening regarding clinical risk and its correlation to invasive coronary angiography (ICA). Methods: A total of 137 patients (61 male and 76 female) referred for CAD screening myocardial perfusion imaging (MPI) between November 2018 and April 2020 were included in the CFR-OR prospective trial. The 10-year risk of cardiovascular death according to the European Society of Cardiology (SCORE) was calculated. SPECT 1-day 99mTc-tetrofosmin protocol was acquired on CZT cardiac-dedicated pinhole cameras. Low-dose thoracic CT was used for coronary calcium score (CCS) evaluation. ICA, when performed within 3 months, was also analyzed. Results: Mean SCORE and mean global MFR were, respectively, 4 ± 3.1% and 2.50 ± 0.74; 34 patients had impaired CFR (using a threshold of 2). There was a significant inverse correlation between MFR and SCORE (p = 0.006), gender (p = 0.019), and number of cardiovascular risk factors (p = 0.01). MFR was significantly reduced in patients with CCS above 1 (p = 0.01). No significant correlation was found between MFR and individual cardiovascular risk factors (dyslipidemia, hypertension, diabetes, or family history of CAD). A total of 23 patients underwent ICA. Global MFR SPECT sensitivity and specificity were 83.3 and 100 %, respectively, with an area under the curve of 0.94. Conclusion: Adding MFR to SPECT MPI for CAD screening on CZT camera may contribute to high-risk patient identification and enhance diagnostic performances. MFR could help physician decision to perform ICA.

Impact of attenuation correction for CZT-SPECT measurement of myocardial blood flow.

OBJECTIVES: Most of cardiac dedicated CZT-SPECT systems are not equipped with CT, whereas PET systems are. We evaluated the impact of AC correction on CZT-SPECT myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurements. METHODS: 104 patients were included. SPECT data were acquired on cadmium zinc telluride (CZT)-based pinhole cardiac camera in listmode using a stress (250 ± 17 MBq)/rest (511 ± 23 MBq) 1-day Tc-99m-tetrofosmin protocol. Low-dose CT was acquired on another SPECT/CT camera in the same position. All analysis was performed using Corridor4DM. RESULTS: Stress and rest MBF were significantly lower when AC was applied (P < 0.001). For regional and global MFR, there was no significant difference between AC and NAC measurements (P > 0.25 at least). Mean global LV MFR was 2.43 ± 0.87 and 2.33 ± 0.89, respectively, for NAC and AC measurements. Using a threshold of 2, 86 patients (83%) remained classified as normal and abnormal regarding global LV MFR whether AC was applied or not. Mean difference between NAC and AC values for the 18 other patients was 0.3. CONCLUSION: AC correction does not significantly affect MFR measurement both in regional and global LV analyses.

Added Value of Myocardial Blood Flow Quantification and Calcium Scoring During CZT SPECT Myocardial Perfusion Imaging for Coronary Artery Disease Screening.

Dedicated cadmium-zinc-telluride cardiac cameras have been shown to provide accurate measurements of absolute myocardial blood flow and flow reserve when PET is not available. We report the case of a 66-year-old woman who underwent 1-day stress/rest myocardial perfusion imaging (MPI) for coronary artery disease (CAD) screening. Relative MPI analysis was normal, whereas low-dose CT showed high calcium score. Myocardial blood flow and flow reserve were strongly impaired in all territories. Coronary angiography confirmed extended CAD. Flow parameters derived from cadmium-zinc-telluride SPECT MPI acquisition and calcium scoring can improve diagnostic accuracy and confidence of CAD.