Critical Appraisal of the Current Role of Myocardial Perfusion Imaging in the Management of Acute Chest Pain.

This paper describes the evolution of nuclear cardiology techniques in the setting of acute coronary syndromes. Since the 1970s, the contribution of nuclear cardiology has been fundamental in delineating the physiopathology and diagnosis of acute myocardial infarction, when electrocardiogram (ECG) did not provide the diagnosis and when cardiac enzyme assessments were at a very early stage. In this clinical situation, at that time the role of pyrophosphate scintigraphy and antimyosin antibodies was important in ensuring diagnostic precision. However, these methods showed limitations and were abandoned in the late 80s and early 90s when therapeutic applications such as thrombolytic therapy, and primary-and rescue-percutaneous coronary intervention (PCI) were introduced. Beginning in the mid-80s, the introduction and widespread use of perfusion tracers such as 99mTc labelled compounds and technological advances such as SPECT, allowed to assess the efficacy of thrombolysis and early revascularization, as well as to assess in depth myocardial salvage. Currently, perfusion SPECT, especially using fast imaging techniques and dedicated cardiac SPECT with solid-state detectors, allows a quick confirmation or exclusion of acute coronary syndromes, particularly in low-to-intermediate likelihood of coronary artery disease (CAD), especially when there are absolute or relative contraindications to the use of coronary computed tomographic angiography (CCTA).

Ischemia-guided vs routine non-culprit vessel angioplasty for patients with ST segment elevation myocardial infarction and multi-vessel disease: the IAEA SPECT STEMI trial.

BACKGROUND: In patients with multi-vessel disease presenting with ST elevation myocardial infarction (STEMI), the efficacy and safety of ischemia-guided, vs routine non-culprit vessel angioplasty has not been adequately studied. METHODS: We conducted an international, randomized, non-inferiority trial comparing ischemia-guided non-culprit vessel angioplasty to routine non-culprit vessel angioplasty, following primary PCI for STEMI. The primary outcome was the between-group difference in percent ischemic myocardium at follow-up stress MPI. All MPI images were processed and analyzed at a central core lab, blinded to treatment allocation. RESULTS: In all, 109 patients were enrolled from nine countries. In the ischemia-guided arm, 25/48 (47%) patients underwent non-culprit vessel PCI following stress MPI. In the routine non-culprit PCI arm, 43/56 (77%) patients underwent angioplasty (86% within 6 weeks of randomization). The median percentage of ischemic myocardium on follow-up imaging (mean 16.5 months) was low, and identical (2.9%) in both arms (difference 0.13%, 95%CI - 1.3%-1.6%, P < .0001; non-inferiority margin 5%). CONCLUSION: A strategy of ischemia-guided non-culprit PCI resulted in low ischemia burden, and was non-inferior to a strategy of routine non-culprit vessel PCI in reducing ischemia burden. Selective non-culprit PCI following STEMI offers the potential for cost-savings, and may be particularly relevant to low-resource settings. (CTRI/2018/08/015384).

Distinct Clinical Features of Post-COVID-19 Vaccination Early-onset Graves' Disease.

CONTEXT: Several case reports of Graves' disease (GD) occurrence after COVID-19 vaccination that are possibly related to the autoimmune syndrome induced by adjuvants (ASIA) were published recently. OBJECTIVE: The aim of our study was to evaluate possible distinctive features in the presentation and clinical course of patients with GD occurring early (within 4 weeks) after COVID-19 vaccination who attended our Endocrine Unit in 2021. METHODS: Patients with a first episode of GD attending a tertiary endocrine center between January 1, 2021, and December 31, 2021, were included. RESULTS: Sixty-four patients with a first episode of GD were seen in 2021: 20 (31.2%) of them had onset within 4 weeks following vaccine administration. Compared with the other 44 patients, the 20 patients with postvaccine early-onset (PoVEO) GD were older (median age 51 years vs 35 years, P = .003) and more likely to be male (40.0% vs 13.6%, P = .018). At diagnosis, the biochemical and immune profiles were similar between the 2 groups. However, at 3 months after starting methimazole, patients with PoVEO GD had significantly lower thyrotropin receptor antibody titer and were taking lower doses of methimazole than the other patients with GD. None in the PoVEO group had sustained free triiodothyronine elevation. CONCLUSION: This relatively large series suggests that in 2021 PoVEO GD may be a new nosologic entity representing one-third of patients evaluated for new-onset GD in our center. Distinctive features included older age at onset, higher male prevalence, and a better initial biochemical and immunologic response to treatment. Further studies are warranted to clinically and biochemically differentiate these cases from sporadically occurring GD.

Comparison between total thyroidectomy and hemithyroidectomy in TIR3B thyroid nodules management.

PURPOSE: Thyroid nodules classified as TIR3B according to SIAPEC 2014 are considered a clinical challenge due to the risk to be malignant. This retrospective study aimed to compare the performances of total thyroidectomy (TT) and hemithyroidectomy (HT) in the surgical management of a consecutive cohort of patients affected by TIR3B thyroid nodule in terms of side effects and the rate of malignancy detected. METHODS: From 2011 to 2019, 136 (111 women, 25 men; average age of 53.5 years) patients having a thyroid nodule with a cytological diagnosis of TIR3B who underwent TT or HT were retrospectively included. RESULTS: Out of 136 patients, 106 (78%) received TT, while the remaining 30 (22%) HT. The final diagnosis was malignant in 65 patients (48%), with follicular variant of papillary carcinoma as the most frequent. The diagnosis of malignancy was significantly more common in the TT group with 56 patients (53%) compared to the HT group with 9 cases (30%) (p = 0.001). Patients who underwent TT were significantly older, had larger nodules and the time between diagnosis and surgery was significantly longer compared to HT (p = 0.001; p0.003; p = 0.002). No main post-surgical complications were registered, except for one case of transient hypocalcemia in a patient who underwent TT. CONCLUSIONS: Our data showed a malignancy rate of TIR3B lesions higher than expected (48%). Both TT and HT seem to be effective approaches for the treatment of TIR3B nodules with a very low rate of post-surgical comorbidities. In the choice of surgical approach, it is crucial to consider the presence of risk factors (clinical and ultrasound characteristics), nodule size, patients' opinion, and surgeon's skills and experience.

[18F]FDG PET/CT and CA-125 in the evaluation of ovarian cancer relapse or persistence: is there any correlation?

BACKGROUND: Ovarian cancer relapse can be diagnosed by serum tumor markers measurements and 18F-fluorodoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) findings. The aim of our study was to analyze the potential relationship between cancer antigen 125 (CA-125) and PET/CT results in patients affected by ovarian cancer. MATERIAL AND METHODS: Ninety-two [18F]FDG PET/CT scans in sixty-one patients with diagnosis of ovarian cancer were analyzed and compared to CA-125 values. PET/CT results were compared to other imaging modalities, histology or follow-up data in order to define its diagnostic accuracy. PET/CT studies were analyzed qualitatively and semiquantitatively by measuring the maximum and mean standardized uptake value body weight max (SUVbw max, SUVbw mean), maximum SUV lean body mass (SUVlbm), maximum SUV body surface area (SUVbsa), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of hypermetabolic lesions. All measurements were compared with CA-125 values. RESULTS: Twenty PET/CT studies were true negative, sixty-three true positive, five false positive and four false negative with sensitivity of 94%, specificity of 80%, negative predictive value of 83%, positive predictive value of 93% and accuracy of 90%. CA-125 levels were significantly correlated with PET/CT results and all PET/CT semiquantitative parameters. CA-125 cutoff values of 17 UI/mL is the best compromise between sensitivity and specificity in discriminating between positive and negative PET/CT result. CONCLUSIONS: [18F]FDG PET/CT has good accuracy in evaluating patients with relapse or persistance of ovarian cancer. CA-125 levels were significantly correlated with metabolic PET/CT parameters.

18F-FDG PET/CT Demonstrating Crossed Cerebellar Diaschisis Due to Germ Cell Tumor of the Basal Ganglia: A Case Report.

ABSTRACT: Germ cell tumors of the basal ganglia are rare neoplasms that usually present with hemiparesis or other neurological symptoms. MR and PET/CT with different tracers have demonstrated their usefulness for the correct assessment of disease. Crossed cerebellar diaschisis refers to a depression in metabolism of a cerebellar hemisphere as a result of contralateral supratentorial lesions. We present a case in which MR and PET/CT were crucial for the assessment of left basal ganglia germ cell tumors with the presence of crossed cerebellar diaschisis.

Correlation between brain glucose metabolism (18F-FDG) and cerebral blood flow with amyloid tracers (18F-Florbetapir) in clinical routine: Preliminary evidences.

OBJECTIVE: This study compared the performance of 18F-Florbetapir PET/CT early acquisitions to 18F-FDG PET/CT. METHODS: We included 12 patients who underwent 18F-FDG PET/CT and a dual-time 18F-Florbetapir PET/CT (1-6 min early-scan and 50 min late-scan). PET/CT were analyzed visually by three nuclear medicine physicians with different experience using a four-point scale (0 = no reduction, 1 = slight, 2 = moderate, 3 = severe reduction) for 18F-Florbetapir early-phase and 18F-FDG images in 10 cortical regions (bilateral frontal, temporal, parietal, occipital, posterior cingulate/precuneus), and 18F-Florbetapir late-phase in the same cortical regions using a three-point scale (0 = normal, 1 = abnormal with minor plaques, 2 = abnormal with major plaques). We used SPM12 for semiquantitative analysis applying a ROI-based correlation analysis (considering precuneus as target region and normalized for the mean global binding), a covariance-analysis taking precuneus as target and a comparison of global DMN (default mode network). RESULTS: Inter-reader agreement was high (Cohen's kappa 0.762 for 18F-FDG, 0.775 for 18F-Florbetapir early-phase and 0.794 for late-phase). Regional visual scores of early-phase and 18F-FDG were significantly correlated (ρ = 0.867). Also ROI-based analysis, global brain visual analysis and DMN comparison revealed concordant results, especially at parietal and precuneus (p < 0.001). CONCLUSIONS: 18F-Florbetapir early-phase scans significantly correlate on quantitative and visual images with 18F-FDG-PET/CT scans, suggesting that amyloid tracer could be instead of 18F-FDG.

18F-fluorodeoxyglucose PET and PET/computed tomography for the evaluation of immunoglobulin G4-related disease: a systematic review.

BACKGROUND: In the last years, 18F-fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) has demonstrated its utility for the evaluation of immunoglobulin G4 (IgG4)-related disease (IgG4RD). The studies are, however, really heterogeneous and different. The aim of this review is, therefore, to analyze the diagnostic performance of 18F-FDG PET and PET/CT for the assessment of IgG4RD. METHODS: A wide literature search of the PubMed/MEDLINE, Scopus, Embase and Cochrane library databases was made to find relevant published articles about the diagnostic performance of 18F-FDG PET or PET/CT for the evaluation of IgG4RD. RESULTS: The comprehensive computer literature search revealed 779 articles. On reviewing the titles and abstracts, 756 articles were excluded because the reported data were not within the field of interest. Twenty-three studies were included in the review. CONCLUSION: Despite some limitations that affect our review, 18F-FDG PET or PET/CT demonstrated the ability to assess IgG4RD both at initial evaluation and after therapy. In general, no correlation between PET/CT parameters and IgG4 serum levels has been reported. A possible role for 18F-FDG PET/CT to drive differential diagnosis with other disease is starting to emerge.

Prognostic Role of Pre-Treatment Metabolic Parameters and Sarcopenia Derived by 2-[18F]-FDG PET/CT in Elderly Mantle Cell Lymphoma.

The goal of this retrospective study was to analyze and compare the prognostic role of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (2-[18F]-FDG PET/CT) features and sarcopenia, estimated by CT of PET in elderly (≥65 years) Mantle Cell Lymphoma (MCL). We recruited 53 patients, who underwent pre-treatment 2-[18F]-FDG PET/CT and end-of-treatment PET/CT, and the main semiquantitative parameters were calculated. Sarcopenia was measured as skeletal muscle index (SMI, cm2/m2) and derived by low-dose PET/CT images at the L3 level. Specific cut-offs for SMI were calculated by receiver operator curve and divided by gender. Metabolic response was evaluated at end-of-treatment PET/CT, applying the Deauville score. Progression Free Survival (PFS) and Overall Survival (OS) were calculated for the whole population and for different subgroups, defined as per different sarcopenia cut-off levels. The specific cut-offs to define sarcopenia were 53 cm2/m2 for male and 45.6 cm2/m2 for female. Thirty-two (60%) patients were defined as sarcopenic. The 3-year and 5-year PFS rates were 29% and 23%, while the 3-year and 5-year OS rates were 43% and 33%. Metabolic response, total metabolic tumor volume (tMTV), total lesion glycolysis (tTLG) and sarcopenia were independent prognostic factors for PFS. Considering OS, no variable was significantly associated. Combination between PET features and sarcopenia may help to predict PFS.

Comparison between Two Different Scanners for the Evaluation of the Role of 18F-FDG PET/CT Semiquantitative Parameters and Radiomics Features in the Prediction of Final Diagnosis of Thyroid Incidentalomas.

The aim of this study was to compare two different tomographs for the evaluation of the role of semiquantitative PET/CT parameters and radiomics features (RF) in the prediction of thyroid incidentalomas (TIs) at 18F-FDG imaging. A total of 221 patients with the presence of TIs were retrospectively included. After volumetric segmentation of each TI, semiquantitative parameters and RF were extracted. All of the features were tested for significant differences between the two PET scanners. The performances of all of the features in predicting the nature of TIs were analyzed by testing three classes of final logistic regression predictive models, one for each tomograph and one with both scanners together. Some RF resulted significantly different between the two scanners. PET/CT semiquantitative parameters were not able to predict the final diagnosis of TIs while GLCM-related RF (in particular GLCM entropy_log2 e GLCM entropy_log10) together with some GLRLM-related and GLZLM-related features presented the best predictive performances. In particular, GLCM entropy_log2, GLCM entropy_log10, GLZLM SZHGE, GLRLM HGRE and GLRLM HGZE resulted the RF with best performances. Our study enabled the selection of some RF able to predict the final nature of TIs discovered at 18F-FDG PET/CT imaging. Classic semiquantitative and volumetric PET/CT parameters did not reveal these abilities. Furthermore, a good overlap in the extraction of RF between the two scanners was underlined.

Different glucose metabolism behavior relating to histotypes in synchronous breast cancers evaluated by [18F]FDG PET-CT.

Glucose metabolism is increased in most aggressive tumors and it is commonly evaluated by positron emission tomography-computed tomography (PET-CT) with 18F-fluorodeoxyglucose ([18F]FDG), measuring the Maximum Standardized Uptake Value (SUVmax) for the assessment. Particularly, it is known that breast cancer expresses different glucose metabolism inrelation to estrogen receptor (ER), progesterone receptor (PR), Ki67 score, tumor grading, tumor size, and Human Epidermal Growth Factor Receptor 2 (HER2). We present an interesting case of a woman with two different, synchronous breast cancers characterized by different glucose metabolism, according to literature knowledge.

Incidental Finding of Testicular Seminoma by 18F-Choline PET/CT in a Prostate Cancer Patient.

ABSTRACT: An 80-year-old man with a history of prostate cancer, treated with radical prostatectomy and bilateral obturator nodal dissection, underwent an 18F-choline PET/CT because of biochemical recurrence. The scan revealed an intense focal uptake in the right testicle. A subsequent orchifunicumlectomy demonstrated the presence of a classic seminoma. At present, 18F-FDG PET/CT is useful for initial staging of testicular cancer and determining the viability of residual masses >3 cm after completion of treatment, especially in patients with seminoma.

Reproducibility of global LV function and dyssynchrony parameters derived from phase analysis of gated myocardial perfusion SPECT: A multicenter comparison with core laboratory setting.

BACKGROUND: Gated myocardial perfusion scintigraphy (GMPS) phase analysis is an important tool to investigate the physiology of left ventricular (LV) dyssynchrony. We aimed to test the performance of GMPS LV function and phase analysis in different clinical settings and on a diverse population. METHODS: This is a post hoc analysis of a prospective, non-randomized, multinational, multicenter cohort study. Clinical evaluation and GMPS prior to cardiac resynchronization therapy (CRT)(baseline) and 6-month post CRT (follow-up) were done. LV end-systolic volume (LVESV), LV end-diastolic volume (LVEDV), LV ejection fraction (LVEF), LV phase standard deviation (LVPSD), and percentage of left ventricle non-viable (PLVNV) were obtained by 10 centers and compared to the core lab. RESULTS: 276 GMPS studies had all data available from individual sites and from core lab. There were no statistically significant differences between all variables except for LVPSD. When subjects with no mechanical dyssynchrony were excluded, LVPSD difference became non-significant. LVESV, LVEF, LVPSD and PLVNV had strong correlation in site against core lab comparison. Bland-Altman plots demonstrated good agreement. CONCLUSIONS: The presented correlation and agreement of LV function and dyssynchrony analysis over different sites with a diverse sample corroborate the strength of GMPS in the management of heart failure in clinical practice.

Clinical and gated SPECT MPI parameters associated with super-response to cardiac resynchronization therapy.

PURPOSE: We sought to evaluate the behavior of cardiac mechanical synchrony as measured by phase SD (PSD) derived from gated MPI SPECT (gSPECT) in patients with super-response after CRT and to evaluate the clinical and imaging characteristics associated with super-response. METHODS: 158 subjects were evaluated with gSPECT before and 6 months after CRT. Patients with an improvement of LVEF > 15% and NYHA class I/II or reduction in LV end-systolic volume > 30% and NYHA class I/II were labeled as super-responders (SR). RESULTS: 34 patients were classified as super-responders (22%) and had lower PSD (32° ± 17°) at 6 months after CRT compared to responders (45° ± 24°) and non-responders 46° ± 28° (P = .02 for both comparisons). Regression analysis identified predictors independently associated with super-response to CRT: absence of previous history of CAD (odds ratio 18.7; P = .002), absence of diabetes mellitus (odds ratio 13; P = .03), and history of hypertension (odds ratio .2; P = .01). CONCLUSION: LV dyssynchrony after CRT implantation, but not at baseline, was significantly better among super-responders compared to non-super-responders. The absence of diabetes, absence of CAD, and history of hypertension were independently associated with super-response after CRT.

Comparison of left ventricle mechanical dyssynchrony parameters in ischemic and non-ischemic patients using 13N-NH3 PET/CT.

BACKGROUND-AIM: The relationship between perfusion pattern and stress-induced changes in Left Ventricular Mechanical Dyssynchrony (LVMD) has been previously described with controversial results using stress-rest perfusion imaging studies. The aim of this study was to assess the relationship between perfusion pattern and stress-induced changes in LVMD usingo regadenoson/rest13N-NH3 PET/CT. METHODS: There were 74 patients who underwent stress-rest 13N-NH PET/CT from January 2014 to October 2018 excluding patients with left bundle branch block, ventricular pacing and myocardial necrosis. The patients were divided into those with reversible perfusion defects at stress (Ischemic group, n = 18) and patients without reversible perfusion defects (non-ischemic group, n = 56). The LVMD parameters included: phase standard deviation (PSD) and phase histogram bandwidth (PHB), after stress and at rest. The ΔPSD (post-stressPSD-restPSD) and ΔPHB (post-stressPHB-restPHB) were calculated to measure stress-induced changes in LVMD. RESULTS: There were no significant differences in LVMD parameters between post-stress and at rest in both groups. The PSD post-stress, ΔPSD and PHB post-stress were significantly higher in the ischemic group. CONCLUSIONS: Using a vasodilator as a stress, the PSD and PHB post-stress and ΔPSD were significantly higher in the ischemic patients than the non-ischemic group, while there were no significant differences in each cohort between stress and rest indices.