Hot spot imaging in cardiovascular diseases: an information statement from SNMMI, ASNC, and EANM.

This information statement from the Society of Nuclear Medicine and Molecular Imaging, American Society of Nuclear Cardiology, and European Association of Nuclear Medicine describes the performance, interpretation, and reporting of hot spot imaging in nuclear cardiology. The field of nuclear cardiology has historically focused on cold spot imaging for the interpretation of myocardial ischemia and infarction. Hot spot imaging has been an important part of nuclear medicine, particularly for oncology or infection indications, and the use of hot spot imaging in nuclear cardiology continues to expand. This document focuses on image acquisition and processing, methods of quantification, indications, protocols, and reporting of hot spot imaging. Indications discussed include myocardial viability, myocardial inflammation, device or valve infection, large vessel vasculitis, valve calcification and vulnerable plaques, and cardiac amyloidosis. This document contextualizes the foundations of image quantification and highlights reporting in each indication for the cardiac nuclear imager.

Potential Cardiac Amyloid PET/CT Imaging Targets for Differentiating Immunoglobulin Light Chain From Transthyretin Amyloidosis.

PURPOSE OF THE REVIEW: Cardiac involvement in amyloidosis plays a critical role in the clinical manifestation and prognostication. Since advanced treatment options for immunoglobulin light chains (AL) or liver-generated protein transthyretin (TTR) are quite different, a non-invasive and comprehensive imaging approach for the identification and characterization of these forms of cardiac amyloidosis is warranted. RECENT FINDINGS: Various 18Flabeled radiotracers and positron emission tomography (PET) imaging have been appreciated as a as a valid and non-invasive diagnostic approach to identify and quantify disease activity of cardiac amyloidosis. Interestingly, applying 18F-florbetapen and delayed PET imaging may even afford the possibility to not only detect cardiac amyloidosis but also to reliably differentiate between AL and TTR, respectively. This review summarizes contributions of cardiac PET imaging for the non-invasive identification and potential differentiation between AL and TTR amyloidosis that likely holds promise to gear medical treatment in the individual patient for an improved outcome.

Incremental Value of FDG-PET in the Evaluation of Cardiac Masses.

PURPOSE OF REVIEW: This study aims to review the various roles and evidence underlying the use of fluorodeoxyglucose (FDG) PET/CT and PET/MR for the assessment of cardiac masses. RECENT FINDINGS: The role of FDG-PET for the evaluation of cardiac masses continues to evolve. Studies have shown that FDG-PET is particularly well-suited for differentiating malignant from benign cardiac lesions based on their metabolic activity. Furthermore, FDG-PET is uniquely positioned to investigate patients with cardiac mass as most malignant cardiac lesions are metastasis. Finally, FDG-PET enables staging of patients with primary malignant cardiac tumor, identification of potential biopsy site, and planning of radiotherapy. FDG-PET is a complementary tool for the evaluation of patients with cardiac mass and can help differentiate benign from malignant lesions, as well as provide whole-body staging.

Clinical Phenotyping of Transthyretin Cardiac Amyloidosis with Bone-Seeking Radiotracers in Heart Failure with Preserved Ejection Fraction.

PURPOSE OF REVIEW: The two most common types of cardiac amyloidosis are caused by fibril deposits of immunoglobulin light chains (AL) and transthyretin (TTR), each with distinct prognosis and clinical management. Cardiac amyloidosis is under-recognized among heart failure patients with preserved ejection fraction (HFpEF). Bone-seeking tracers like 99mTc-PYP and 99mTc-DPD have long been used to identify cardiac amyloidosis, and more recently, to differentiate TTR from AL cardiac amyloidosis in symptomatic patients. However, results are mainly derived from single-center retrospective studies, with comparable but not standardized imaging protocols and interpretation criteria. RECENT FINDINGS: The clinical scope of cardiac amyloidosis among HFpEF patients and current literature supporting the use of bone-seeking tracers for TTR cardiac amyloidosis are presented. The differences of imaging techniques for cardiac amyloid and bone disease evaluation, bone tracer pharmacodynamics, and imaging interpretation criteria for cardiac amyloidosis diagnosis are discussed. Finally, a diagnostic algorithm to use bone scintigraphy in cardiac amyloidosis diagnosis among HFpEF patients is proposed. Bone scintigraphy with 99mTc-PYP or 99mTc-DPD can be a useful tool with high sensitivity and specificity for detecting TTR-related cardiac amyloidosis in patients with HFpEF. It is needed to standardize the imaging protocol and interpretation criteria and to perform prospective clinical studies.

Myocardial perfusion imaging: Lessons learned and work to be done-update.

As the second term of our commitment to Journal begins, we, the editors, would like to reflect on a few topics that have relevance today. These include prognostication and paradigm shifts; Serial testing: How to handle data? Is the change in perfusion predictive of outcome and which one? Ischemia-guided therapy: fractional flow reserve vs perfusion vs myocardial blood flow; positron emission tomography (PET) imaging using Rubidium-82 vs N-13 ammonia vs F-18 Flurpiridaz; How to differentiate microvascular disease from 3-vessel disease by PET? The imaging scene outside the United States, what are the differences and similarities? Radiation exposure; Special issues with the new cameras? Is attenuation correction needed? Are there normal databases and are these specific to each camera system? And finally, hybrid imaging with single-photon emission tomography or PET combined with computed tomography angiography or coronary calcium score. We hope these topics are of interest to our readers.

High Concordance Between Mental Stress-Induced and Adenosine-Induced Myocardial Ischemia Assessed Using SPECT in Heart Failure Patients: Hemodynamic and Biomarker Correlates.

UNLABELLED: Mental stress can trigger myocardial ischemia, but the prevalence of mental stress-induced ischemia in congestive heart failure (CHF) patients is unknown. We characterized mental stress-induced and adenosine-induced changes in myocardial perfusion and neurohormonal activation in CHF patients with reduced left-ventricular function using SPECT to precisely quantify segment-level myocardial perfusion. METHODS: Thirty-four coronary artery disease patients (mean age±SD, 62±10 y) with CHF longer than 3 mo and ejection fraction less than 40% underwent both adenosine and mental stress myocardial perfusion SPECT on consecutive days. Mental stress consisted of anger recall (anger-provoking speech) followed by subtraction of serial sevens. The presence and extent of myocardial ischemia was quantified using the conventional 17-segment model. RESULTS: Sixty-eight percent of patients had 1 ischemic segment or more during mental stress and 81% during adenosine. On segment-by-segment analysis, perfusion with mental stress and adenosine were highly correlated. No significant differences were found between any 2 time points for B-type natriuretic peptide, tumor necrosis factor-α, IL-1b, troponin, vascular endothelin growth factor, IL-17a, matrix metallopeptidase-9, or C-reactive protein. However, endothelin-1 and IL-6 increased, and IL-10 decreased, between the stressor and 30 min after stress. Left-ventricular end diastolic dimension was 179±65 mL at rest and increased to 217±71 after mental stress and 229±86 after adenosine (P<0.01 for both). Resting end systolic volume was 129±60 mL at rest and increased to 158±66 after mental stress (P<0.05) and 171±87 after adenosine (P<0.07), with no significant differences between adenosine and mental stress. Ejection fraction was 30±12 at baseline, 29±11 with mental stress, and 28±10 with adenosine (P=not significant). CONCLUSION: There was high concordance between ischemic perfusion defects induced by adenosine and mental stress, suggesting that mental stress is equivalent to pharmacologic stress in eliciting clinically significant myocardial perfusion defects in CHF patients. Cardiac dilatation suggests clinically important changes with both conditions. Psychosocial stressors during daily life may contribute to the ischemic burden of CHF patients with coronary artery disease.

Giant Cell Tumor of the Tendon Sheath With Discordant Metabolism as a False Positive on Staging of Mantle Cell Lymphoma.

A baseline F-FDG PET/CT scan in a patient with mantle cell lymphoma showed diffuse minimally FDG-avid lymphadenopathy and splenomegaly. There was also a focus of uptake in the left subscapularis muscle without a CT correlate. A post-chemotherapy scan showed interval decrease in size, and resolution of FDG uptake, of the lymph nodes and spleen. Persistent activity was seen in the subscapularis muscle. Posttreatment biopsy of the FDG-avid lesion showed a benign giant cell tumor of tendon sheath. This case illustrates that a lesion with a markedly discordant SUV should raise suspicion for a second process.

FDG uptake in liposclerosing myxofibrous tumor causes upstaging of Hodgkin lymphoma.

A 22-year-old woman with Hodgkin lymphoma underwent a staging 18F-FDG PET/CT scan, which showed an intense uptake in the right proximal femur, in addition to FDG-avid mediastinal and cervical lymph nodes. The patient thus was diagnosed with stage IV lymphoma with bone marrow involvement. Postchemotherapy restaging scan showed complete resolution of nodal uptake but persistent activity in the right femur. Radiography and biopsy confirmed liposclerosing myxofibrous tumor.

A pilot study of FDG PET/CT detects a link between brown adipose tissue and breast cancer.

BACKGROUND: Breast cancer is the second most lethal cancer in women. Understanding biological mechanisms that cause progression of this disease could yield new targets for prevention and treatment. Recent experimental studies suggest that brown adipose tissue (BAT) may play a key role in breast cancer progression. The primary objective for this pilot study was to determine if the prevalence of active BAT in patients with breast cancer is increased compared to cancer patients with other malignancies. METHODS: We retrospectively analyzed data from 96 breast cancer patients who had FDG PET/CT scan for routine staging at the University of Maryland and 96 age- and weight-matched control female patients with other malignancies (predominantly colon cancer) who had undergone FDG PET/CT imaging on the same day. Data on the distribution (bilateral upper neck, supraclavicular and paraspinal regions) and intensity (SUVmax) of active BAT were evaluated by 2 Nuclear Medicine physicians, blinded to the clinical history. RESULTS: We found sufficient evidence to conclude that based on our sample data the prevalence of active BAT in breast cancer patients' group is significantly different from that in the control group. The estimated frequency of BAT activity was 3 fold higher in breast cancer patients as compared to controls with other cancers, (16.7% vs. 5.2%, respectively, p = 0.019). When patients were stratified by age in order to determine the possible impact of age related hormonal changes on active BAT among the younger women (≤ 55 years of age), 25.6% breast cancer patients exhibited BAT activity compared to only 2.8% in control women (p = 0.007). In contrast, among the older women (> 55 years of age), the prevalence of active BAT was similar among breast cancer and control women (10.7% vs 6.7%). CONCLUSIONS: In breast cancer patients prevalence of BAT activity on FDGPET/CT is 3-fold greater than in age- and body weight-matched patients with other solid tumor malignancies; this difference is particularly striking among younger women aged < =55. In summary, our retrospective clinical data provide support to pursue prospective clinical and translational studies to further define the role of BAT in breast cancer development and progression.