Factors Associated with Myocardial Uptake on Oncologic Somatostatin PET Investigations and Differentiation from Myocardial Uptake of Acute Myocarditis

Myocardial somatostatin PET uptake is observed not only in most patients with acute myocarditis (AM) but also in some oncology patients referred for routine somatostatin PET. This raises concerns about the specificity of somatostatin PET for detecting myocarditis. The current study aims to identify factors associated with the detection of myocardial uptake on somatostatin PET scans recorded for oncology indications and differential PET criteria that characterize myocardial uptake in AM patients. Methods: We analyzed factors associated with the detection of myocardial [68Ga]Ga-DOTATOC uptake in 508 [68Ga]Ga-DOTATOC PET scans from 178 patients, performed for confirmed or suspected oncologic disease (Onc-PET) and PET criteria that could differentiate myocardial [68Ga]Ga-DOTATOC uptake in 31 patients with MRI-ascertained AM (AM-PET) from that in the Onc-PET group. Results: Significant myocardial uptake was detected in 137 (26.9%) Onc-PET scans and was independently associated with somatostatin analog treatment (exp(β), 0.805; 95% CI, 0.728-0.890; P < 0.001) and age (exp(β), 1.005; 95% CI, 1.001-1.009; P = 0.012). A comparable model was selected for predicting the myocardial-to-blood SUVmax ratio using somatostatin analog treatment (P < 0.001) and history of coronary artery disease (P = 0.022). Myocardial uptake was detected in 12.9% (25/193) of Onc-PET scans from patients treated with somatostatin analogs but in 43.4% (59/136) of untreated patients over the median age of 64 y. Myocardial uptake was apparent in all 31 AM-PET scans, with volume and intensity of uptake dramatically higher than in the 137 Onc-PET scans showing myocardial uptake. A myocardial-to-blood SUVmax ratio threshold of 2.20 provided a sensitivity of 87% (27/31) and a specificity of 88% (44/50) for differentiating myocardial uptake between the AM-PET group and an Onc-PET group restricted to patients with clinical characteristics comparable to those of patients in the AM-PET group (≤64 y of age, no coronary artery disease history, and no somatostatin agonists). A myocardial uptake volume threshold of 18 cm3 provided comparable diagnostic accuracy (sensitivity, 84% [26/31]; specificity, 94% [47/50]). Conclusion: Myocardial uptake was detected in 26.9% of somatostatin PET scans recorded for oncology indications. This rate was decreased by somatostatin analog treatments and increased in older individuals. However, somatostatin PET scans, analyzed with the quantitative criterion of uptake intensity or volume, are able to identify AM and to differentiate it from myocardial uptake of other origins.

Association between baseline hemodynamic indices, cardiotoxicity risk, and survival in women with breast cancer

BACKGROUND

The outcome of breast cancer (BrCa) women monitored by low-dose equilibrium radionuclide angiography (ERNA) remains challenging to predict.

AIM

This study aims to determine whether heart rate (HR)/blood pressure (BP) ratio-based indexes, previously confirmed to predict outcomes of various diseases, also predict BrCa-therapy-related cardiotoxicity and survival.

METHODS

Predictors of cardiotoxicity and survival were determined among pre-therapy variables, including shock index ([SI HR/systolic BP) and age-adjusted SI (ASI), in a female BrCa cohort with normal baseline ERNA-left ventricular ejection fraction (LVEF).

RESULTS

We included 274 women with a median age of 54.8 (interquartile range: 45.5-65.4) years, 271 treated with anthracyclines and 96 with trastuzumab. During a median follow-up of 25.9 (18.6-33.5) months, 31 women developed cardiotoxicity (LVEF: <50% and ≥10% drop from baseline), and 25 died. Baseline ASI was a multivariate predictor (p < 0.001) of (i) cardiotoxicity, in association with trastuzumab treatment (p = 0.010), and LV end-diastolic volume (p = 0.001) and (ii) survival, in association with metastasis (p < 0.001) and estimated glomerular filtration rate (p = 0.008). Cardiotoxicity poorly impacted survival (p = 0.064). The 36-month cardiotoxicity and mortality rates were markedly higher for patients in the upper half of baseline ASI values (ASI: >30 years min-1.mmHg-1, 16.5% and 20.7%, respectively) than in the lower half (7.6% and 4.5%, respectively, both p < 0.05).

CONCLUSIONS

In BrCa women with normal baseline ERNA-LVEF, HR/BP ratio-based indexes unmask hemodynamic profiles associated with increased cardiotoxicity risk and decreased survival, highlighting the need for a comprehensive assessment of cardiac- and vascular-related risks in BrCa women monitored by ERNA.

CONDENSED ABSTRACT

In a cohort of 274 women BrCa women who were monitored by ERNA for potentially cardiotoxic drugs (anthracyclines or trastuzumab) and who had no history of cardiac disease and a normal left ventricular ejection fraction before treatment, baseline indexes based on HR/BP ratios unmask hemodynamic profiles strongly associated with an increased risk of cardiotoxicity and subsequently decreased survival. Although further validations in other cohorts are needed, these findings highlight the need for a more comprehensive assessment of the cardiac- and vascular-related risk in BrCa women monitored by ERNA.

Ultra-fast whole-body bone tomoscintigraphies achieved with a high-sensitivity 360° CZT camera and a dedicated deep-learning noise reduction algorithm

This study aimed to determine whether the whole-body bone Single Photon Emission Computed Tomography (SPECT) recording times of around 10 min, routinely provided by a high-sensitivity 360° cadmium and zinc telluride (CZT) camera, can be further reduced by a deep-learning noise reduction (DLNR) algorithm.

METHODS

DLNR was applied on whole-body images recorded after the injection of 545 ± 33 MBq of [99mTc]Tc-HDP in 19 patients (14 with bone metastasis) and reconstructed with 100%, 90%, 80%, 70%, 60%, 50%, 40%, and 30% of the original SPECT recording times.

RESULTS

Irrespective of recording time, DLNR enhanced the contrast-to-noise ratios and slightly decreased the standardized uptake values of bone lesions. Except in one markedly obese patient, the quality of DLNR processed images remained good-to-excellent down to 60% of the recording time, corresponding to around 6 min SPECT-recording.

CONCLUSION

Ultra-fast SPECT recordings of 6 min can be achieved when DLNR is applied on whole-body bone 360° CZT-SPECT.

Assessment of a one-week ketogenic diet on brain glycolytic metabolism and on the status epilepticus stage of a lithium-pilocarpine rat model

The ketogenic diet (KD) has been shown to be effective in refractory epilepsy after long-term administration. However, its interference with short-term brain metabolism and its involvement in the early process leading to epilepsy remain poorly understood. This study aimed to assess the effect of a short-term ketogenic diet on cerebral glucose metabolic changes, before and after status epilepticus (SE) in rats, by using [18F]-FDG PET. Thirty-nine rats were subjected to a one-week KD (KD-rats, n = 24) or to a standard diet (SD-rats, n = 15) before the induction of a status epilepticus (SE) by lithium-pilocarpine administrations. Brain [18F]-FDG PET scans were performed before and 4 h after this induction. Morphological MRIs were acquired and used to spatially normalize the PET images which were then analyzed voxel-wisely using a statistical parametric-based method. Twenty-six rats were analyzed (KD-rats, n = 15; SD-rats, n = 11). The 7 days of the KD were associated with significant increases in the plasma β-hydroxybutyrate level, but with an unchanged glycemia. The PET images, recorded after the KD and before SE induction, showed an increased metabolism within sites involved in the appetitive behaviors: hypothalamic areas and periaqueductal gray, whereas no area of decreased metabolism was observed. At the 4th hour following the SE induction, large metabolism increases were observed in the KD- and SD-rats in areas known to be involved in the epileptogenesis process late-i.e., the hippocampus, parahippocampic, thalamic and hypothalamic areas, the periaqueductal gray, and the limbic structures (and in the motor cortex for the KD-rats only). However, no statistically significant difference was observed when comparing SD and KD groups at the 4th hour following the SE induction. A one-week ketogenic diet does not prevent the status epilepticus (SE) and associated metabolic brain abnormalities in the lithium-pilocarpine rat model. Further explorations are needed to determine whether a significant prevention could be achieved by more prolonged ketogenic diets and by testing this diet in less severe experimental models, and moreover, to analyze the diet effects on the later and chronic stages leading to epileptogenesis.

Role of aldosterone in mid- and long-term left ventricular remodelling after acute myocardial infarction: The REMI study

AIMS

Whether aldosterone levels after myocardial infarction (MI) are associated with mid- and long-term left ventricular (LV) remodelling in the era of systematic use of renin-angiotensin system inhibitors is uncertain. We prospectively investigated the relationship between aldosterone levels and mid- and long-term LV remodelling in patients with acute MI.

METHODS AND RESULTS

Plasma aldosterone was measured in 119 patients successfully treated by primary percutaneous coronary angioplasty for a first acute ST-elevation MI (STEMI) 2-4 days after the acute event. LV volumes were assessed by cardiac magnetic resonance (CMR) and transthoracic echocardiography (TTE) in the same timeframe and 6 months later. LV assessment was repeated by TTE 3-9 years after MI (n = 80). The median aldosterone level at baseline was 23.1 [16.8; 33.1] pg/ml. In the multivariable model, higher post-MI aldosterone concentration was significantly associated with more pronounced increase in LV end-diastolic volume index (TTE: β ± standard error [SE]: 0.113 ± 0.046, p = 0.015; CMR: β ± SE: 0.098 ± 0.040, p = 0.015) and LV end-systolic volume index (TTE: β ± SE: 0.083 ± 0.030, p = 0.008; CMR: β ± SE: 0.064 ± 0.032, p = 0.048) at 6-month follow-up, regardless of the method of assessment. This result was consistent also in patients with a LV ejection fraction (LVEF) >40%. The association between baseline plasma aldosterone and adverse LV remodelling did not persist at the 3-9-year follow-up evaluation.

CONCLUSION

Aldosterone concentration in the acute phase was associated with adverse LV remodelling in the medium term, even in the subgroup of patients with LVEF >40%, suggesting a potential role of the mineralocorticoid system in post-MI adverse remodelling. Plasma aldosterone was no longer associated with LV remodelling in the long term (NCT01109225).

Semi-automated segmentation methods of SSTR PET for dosimetry prediction in refractory meningioma patients treated by SSTR-targeted peptide receptor radionuclide therapy

OBJECTIVES

Tumor dosimetry with somatostatin receptor-targeted peptide receptor radionuclide therapy (SSTR-targeted PRRT) by 177Lu-DOTATATE may contribute to improved treatment monitoring of refractory meningioma. Accurate dosimetry requires reliable and reproducible pretherapeutic PET tumor segmentation which is not currently available. This study aims to propose semi-automated segmentation methods to determine metabolic tumor volume with pretherapeutic 68Ga-DOTATOC PET and evaluate SUVmean-derived values as predictive factors for tumor-absorbed dose.

METHODS

Thirty-nine meningioma lesions from twenty patients were analyzed. The ground truth PET and SPECT volumes (VolGT-PET and VolGT-SPECT) were computed from manual segmentations by five experienced nuclear physicians. SUV-related indexes were extracted from VolGT-PET and the semi-automated PET volumes providing the best Dice index with VolGT-PET (Volopt) across several methods: SUV absolute-value (2.3)-threshold, adaptative methods (Jentzen, Otsu, Contrast-based method), advanced gradient-based technique, and multiple relative thresholds (% of tumor SUVmax, hypophysis SUVmean, and meninges SUVpeak) with optimal threshold optimized. Tumor-absorbed doses were obtained from the VolGT-SPECT, corrected for partial volume effect, performed on a 360° whole-body CZT-camera at 24, 96, and 168 h after administration of 177Lu-DOTATATE.

RESULTS

Volopt was obtained from 1.7-fold meninges SUVpeak (Dice index 0.85 ± 0.07). SUVmean and total lesion uptake (SUVmeanxlesion volume) showed better correlations with tumor-absorbed doses than SUVmax when determined with the VolGT (respective Pearson correlation coefficients of 0.78, 0.67, and 0.56) or Volopt (0.64, 0.66, and 0.56).

CONCLUSION

Accurate definition of pretherapeutic PET volumes is justified since SUVmean-derived values provide the best tumor-absorbed dose predictions in refractory meningioma patients treated by 177Lu-DOTATATE. This study provides a semi-automated segmentation method of pretherapeutic 68Ga-DOTATOC PET volumes to achieve good reproducibility between physicians.

CLINICAL RELEVANCE STATEMENT

SUVmean-derived values from pretherapeutic 68Ga-DOTATOC PET are predictive of tumor-absorbed doses in refractory meningiomas treated by 177Lu-DOTATATE, justifying to accurately define pretherapeutic PET volumes. This study provides a semi-automated segmentation of 68Ga-DOTATOC PET images easily applicable in routine.

KEY POINTS

• SUVmean-derived values from pretherapeutic 68Ga-DOTATOC PET images provide the best predictive factors of tumor-absorbed doses related to 177Lu-DOTATATE PRRT in refractory meningioma. • A 1.7-fold meninges SUVpeak segmentation method used to determine metabolic tumor volume on pretherapeutic 68Ga-DOTATOC PET images of refractory meningioma treated by 177Lu-DOTATATE is as efficient as the currently routine manual segmentation method and limits inter- and intra-observer variabilities. • This semi-automated method for segmentation of refractory meningioma is easily applicable to routine practice and transferrable across PET centers.

177Lu-PSMA Treatment Monitoring Through Serial Fast Whole-Body Tomoscintigraphies Recorded With a Latest-Generation CZT-Camera

ABSTRACT

The tomoscintigraphy monitoring of 177Lu-prostate-specific membrane antigen (PSMA) treatment may be helpful for quality control and predicting therapeutic response. Furthermore, the drawbacks of relatively low image quality and extended recording times can be overcome by new CZT-cameras providing fast, high-quality, whole-body recordings. Although still requiring further larger-scale confirmation, the current case report demonstrates that these CZT-cameras have the potential to provide straightforward and comprehensive 177Lu-PSMA treatment monitoring, that is, <20-minute whole-body tomoscintigraphy recording, tumor activities concordant with those from 68Ga-PSMA PET, and no requirement for any additional tracer injection.

Machine Learning-Based Phenogrouping in MVP Identifies Profiles Associated With Myocardial Fibrosis and Cardiovascular Events

BACKGROUND

Structural changes and myocardial fibrosis quantification by cardiac imaging have become increasingly important to predict cardiovascular events in patients with mitral valve prolapse (MVP). In this setting, it is likely that an unsupervised approach using machine learning may improve their risk assessment.

OBJECTIVES

This study used machine learning to improve the risk assessment of patients with MVP by identifying echocardiographic phenotypes and their respective association with myocardial fibrosis and prognosis.

METHODS

Clusters were constructed using echocardiographic variables in a bicentric cohort of patients with MVP (n = 429, age 54 ± 15 years) and subsequently investigated for their association with myocardial fibrosis (assessed by cardiac magnetic resonance) and cardiovascular outcomes.

RESULTS

Mitral regurgitation (MR) was severe in 195 (45%) patients. Four clusters were identified: cluster 1 comprised no remodeling with mainly mild MR, cluster 2 was a transitional cluster, cluster 3 included significant left ventricular (LV) and left atrial (LA) remodeling with severe MR, and cluster 4 included remodeling with a drop in LV systolic strain. Clusters 3 and 4 featured more myocardial fibrosis than clusters 1 and 2 (P < 0.0001) and were associated with higher rates of cardiovascular events. Cluster analysis significantly improved diagnostic accuracy over conventional analysis. The decision tree identified the severity of MR along with LV systolic strain <21% and indexed LA volume >42 mL/m2 as the 3 most relevant variables to correctly classify participants into 1 of the echocardiographic profiles.

CONCLUSIONS

Clustering enabled the identification of 4 clusters with distinct echocardiographic LV and LA remodeling profiles associated with myocardial fibrosis and clinical outcomes. Our findings suggest that a simple algorithm based on only 3 key variables (severity of MR, LV systolic strain, and indexed LA volume) may help risk stratification and decision making in patients with MVP. (Genetic and Phenotypic Characteristics of Mitral Valve Prolapse, NCT03884426; Myocardial Characterization of Arrhythmogenic Mitral Valve Prolapse [MVP STAMP], NCT02879825).

Volume of the proximal half of the thoracic aorta is the most comprehensive FDG-PET/CT indicator of arterial aging throughout adulthood

INTRODUCTION

¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) and computed tomography (CT) features of the proximal and more elastic half of the thoracic aorta are known to correlate with aorta stiffness in older populations. This prospective study aimed to analyze the changes in these FDG-PET/CT features between young, middle-aged, and older adults, and investigate associations with arterial stiffness and blood pressure (BP).

METHODS

Young (< 40 years), middle-aged (40-to-60 years), and older (> 60 years) adults, who underwent an FDG-PET/CT, were prospectively recruited. FDG-PET/CT features of the proximal half of the thoracic aorta were analyzed relative to the age categories, BP and carotid-femoral pulse wave velocity (PWV), a reference indicator of aorta stiffness.

RESULTS

We included 79 patients (38 women; 22 young, 19 middle-aged, and 38 older adults). An increase in age category was associated with increases in mean standardized uptake values (SUVs) of blood and aorta and most significantly in aorta SUV heterogeneity, represented by SUV standard deviation (SUV-SD), aorta calcification volume, and the aorta volume indexed to body surface area. However, this indexed aorta volume was the sole variable: (i) exhibiting a stepwise increase from young (median: 25 cm³/m² [interquartile range: 20-28 cm³/m²]), to middle-aged (41 [30-48] cm³/m², p < 0.001 vs. Young), and older (62 [44-70] cm³/m², p < 0.001 vs. middle-age) adults, and (ii) selected in the multivariate predictions of systolic, diastolic, and pulse BP. Indexed aorta volume was also a multivariate predictor of PWV but in association with SUV-SD and hypertension.

CONCLUSION

In a population of patients referred to an FDG-PET/CT investigation, the indexed volume of the proximal and more elastic half of the thoracic aorta is the most comprehensive indicator of arterial aging. This imaging parameter exhibits a stepwise increase from young to middle-aged and older adults, is strongly linked to inter-individual changes in both arterial stiffness and BP, and thus, could help assess the early phases of arterial aging. Trial registration ClinicalTrial.gov, NCT03345290. Registered 17 November 2017, https://clinicaltrials.gov/ct2/show/NCT03345290?term=NCT03345290&draw=2&rank=1.

Routine first-line detection of breast cancer therapy-related cardiotoxicity by serial, fast and ultra-low-dose equilibrium radionuclide angiography

BACKGROUND

This study assesses a first-line left ventricular ejection fraction (LVEF) monitoring provided by an ultra-low-dose equilibrium radionuclide angiography (ERNA) in breast cancer women treated with potentially cardiotoxic drugs and analyzes patient outcome based on the ERNA results.

METHODS

Breast cancer women treated with anthracyclines, followed or not by trastuzumab, were monitored using ERNA with a high-sensitivity CZT-camera. Calibrated LVEF measurements were obtained with an almost threefold reduction of radiation doses and 10-min recording times.

RESULTS

During a mean 24 ± 6 months follow-up, 552 ERNAs with a mean effective dose of 2.3 ± 0.6 mSv were performed in 195 women, among whom 22 (11%) presented both ERNA criteria of cardiotoxicity (LVEF < 50% and > 10% drop from baseline; Tox + group), 35 (18%) only one criterion (Tox ± group), and 138 (71%) neither (Tox - group). This ERNA-based classification correlated with trastuzumab-anthracycline treatment (p = 0.001), prior cardiovascular disease (p = 0.018), and cardiac outcome, with a 30-month survival with no cardiotoxicity-driven drug regimen changes of 97 ± 2% in Tox -, 60 ± 13% in Tox ± and 36 ± 13% in Tox + (p < 0.001) groups.

CONCLUSION

First-line detection of breast cancer therapy-related cardiotoxicity by ultra-low-dose ERNA provides consistent results, confirming the excellent cardiac outcome for the greatest majority of women with no ERNA cardiotoxicity criteria.

Detection of acute myocarditis by ECG-triggered PET imaging of somatostatin receptors compared to cardiac magnetic resonance: preliminary results

Somatostatin receptors are overexpressed by inflammatory cells but not by cardiac cells, under normal conditions. This study assesses the detection of acute myocarditis by the ECG-triggered digital-PET imaging of somatostatin receptors (68Ga-DOTATOC-PET), as compared to Cardiac Magnetic Resonance (CMR) imaging, which is the reference diagnostic method in this setting.

METHODS

Fourteen CMR-defined acute myocarditis patients had a first 15-minutes ECG-triggered 68Ga-DOTATOC PET recording, 4.4 ± 3.0 days from peak troponin, and 10 had a second 4.3 ± 0.3 months later. Myocardial/blood SUVmax ratio was analyzed relative to the normal upper limit of 2.18, which had been previously determined from oncology 68Ga-DOTATOC-PET recordings of patients with a similar age range as the myocarditis patients.

RESULTS

An increased myocardial 68Ga-DOTATOC uptake relative to blood activity was invariably observed during the acute phase. SUVmax ratio exceeded 2.18 in all patients during the acute phase but also in 3/10 patients at 4-months, at a time when there were no more signs of active inflammation on CMR. A residual myocardial 68Ga-DOTATOC uptake was still observed on all gated-PET cine loops at 4-months.

CONCLUSION

These preliminary results suggest that 68Ga-DOTATOC ECG-triggered digital-PET may be as sensitive as CMR at detecting myocarditis during the acute phase and more sensitive at later stages.

Targeted therapy monitoring of BRAF-V600-mutant Erdheim-Chester disease by fast quantitative whole-body bone CZT-tomoscintigraphies

Erdheim-Chester disease (ECD) is a rare histiocytosis due to proto-oncogene mutations, primarily affecting the long bones and possibly being treated by novel targeted therapies. ¹⁸F-FDG PET is a reference technique for ECD assessment. However, we present a case where easier and more objective monitoring of the ECD-related bone metabolism abnormalities under treatment was obtained with the standardized uptake value-based information provided by fast whole-body [Tc-99 m]-HDP bone tomoscintigraphies (QWBT) recorded with a high-sensitivity CZT-camera/computed tomography (CT) hybrid system.

Myocardial deformation in malignant mitral valve prolapse: A shifting paradigm to dynamic mitral valve-ventricular interactions

Objectives

This study sought to assess the value of myocardial deformation using strain echocardiography in patients with mitral valve prolapse (MVP) and severe ventricular arrhythmia and to evaluate its impact on rhythmic risk stratification.

Background

MVP is a common valvular affection with an overly benign course. Unpredictably, selected patients will present severe ventricular arrhythmia.

Methods

Patients with MVP as the only cause of aborted SCD (MVP-aSCD: ventricular fibrillation and monomorphic and polymorphic ventricular tachycardia) with no other obvious reversible cause were identified. Nonconsecutive patients referred for the echocardiographic evaluation of MVP were enrolled as a control cohort and dichotomized according to the presence or absence of premature ventricular contractions (MVP-PVC or MVP-No PVC, respectively). All patients had a comprehensive strain assessment of mechanical dispersion (MD), postsystolic shortening, and postsystolic index (PSI).

Results

A total of 260 patients were enrolled (20 MVP-aSCD, 54 MVP-PVC, and 186 MVP-No PVC). Deformation pattern discrepancies were observed with a higher PSI value in MVP-aSCD than that in MVP-PVC (4.6 ± 2.0 vs. 2.9 ± 3.7, p = 0.014) and a higher MD value than that in MVP-No PVC (46.0 ± 13.0 vs. 36.4 ± 10.8, p = 0.002). In addition, PSI and MD increased the prediction of severe ventricular arrhythmia on top of classical risk factors in MVP. Net reclassification improvement was 61% (p = 0.008) for PSI and 71% (p = 0.001) for MD.

Conclusions

In MVP, myocardial deformation analysis with strain echocardiography identified specific contraction patterns with postsystolic shortening leading to increased values of PSI and MD, translating the importance of mitral valve-myocardial interactions in the arrhythmogenesis of severe ventricular arrhythmia. Strain echocardiography may provide important implications for rhythmic risk stratification in MVP.

Aortic regurgitation: multimodal assessment of quantification and impact

BACKGROUND

The assessment of severity of aortic regurgitation (AR) by transthoracic echocardiography (TTE) remains challenging in routine practice. Contemporary guidelines recommend cardiovascular magnetic resonance imaging (CMR) in patients with significant disease and suboptimal TTE images. The objective of this study was to assess the role of CMR in the evaluation of severity of AR and to compare both modalities in the quantification of regurgitation and left ventricular volumes.

METHODS

Fifty consecutive patients who had isolated chronic AR and who underwent TTE and CMR within an interval of less than three months between May 2009 and June 2020 were included. The main indication for CMR was difficulties in quantifying AR, either because of lack of multiparametric analysis (only one method possible) or because of discrepancies in the different methods by TTE.

RESULTS

In 25 patients, precise grading of AR was not possible by echocardiography. Among them, CMR finally detected seven patients with mild AR, 11 with moderate AR and seven with severe AR. For the 25 patients who had AR quantification by TTE, there was concordance between TTE and CMR in only seven patients (28%), and the AR was re-graded by CMR in 18 patients, including eight patients with severe AR by TTE and moderate AR by CMR. The concordance between TTE and CMR was weakly significant (intraclass correlation coefficient = 0.39, 95% confidence interval: 0.003-0.67, p = 0.02). There was a moderate correlation between left ventricular volumes measured by TTE and by CMR (left ventricular end-diastolic volume: r = 0.57; p = 0.01; left ventricular end-systolic volume: r = 0.47, p = 0.01) but regurgitant volumes were not correlated (r = 0.04; p = 0.8). No TTE parameter of quantification was correlated with regurgitant volume measured by CMR.

CONCLUSIONS

The concordance of AR quantification by CMR and TTE was weak. CMR re-graded some patients with severe AR by TTE into moderate AR. This should motivate practitioners to systematically assess all significant AR by CMR in order to improve quantification and optimise clinical management.

The detection of infectious endocarditis may be enhanced by a repeat FDG-PET while maintaining patients on a ketogenic diet

BACKGROUND

This study aims to determine whether the suppression of myocardial FDG uptake and detection of infectious endocarditis (IE) may be enhanced when FDG-PET is repeated on the next day while maintaining patients on a ketogenic diet in the interim.

METHODS

Seventeen patients with definite IE underwent FDG-PET investigations both after a conventional metabolic preparation (> 12-hour fast after a low-carbohydrate evening meal) and a subsequent 12-hour extension of the low-carbohydrate diet followed by an additional > 12-hour fast.

RESULTS

Plasma biomarkers showed increased ketogenic metabolism between the two FDG-PET scans. A myocardial FDG uptake persisted on the 1st PET in 9 patients (53%) for whom myocardial FDG uptake decreased significantly on the 2nd PET (SUVmax: 6.05 ± 3.25 vs 4.32 ± 3.47, P = 0.021), resulting in an enhancement in the diagnostic confidence of IE in 6 cases. These enhancements were not documented in the 8 patients exhibiting a total suppression of myocardial FDG uptake on the 1st PET.

CONCLUSIONS

Better suppression of myocardial uptake and enhanced detection of IE may be achieved when an FDG-PET, showing an incomplete suppression of the myocardial FDG uptake, is repeated as soon as the next day, while maintaining patients on a ketogenic diet in the interim.

Metabolic connectivity is associated with seizure outcome in surgically treated temporal lobe epilepsies: A 18F-FDG PET seed correlation analysis

¹⁸F-FDG PET provides high sensitivity for the pre-surgical assessment of drug-resistant temporal lobe epilepsy (TLE). However, little is known about the metabolic connectivity of epileptogenic networks involved. This study therefore aimed to evaluate the association between metabolic connectivity and seizure outcome in surgically treated TLE.

METHODS

The study included 107 right-handed patients that had undergone a presurgical interictal ¹⁸F-FDG PET assessment followed by an anterior temporal lobectomy and were classified according to seizure outcome 2 years after surgery. Metabolic connectivity was evaluated by seed correlation analysis in left and right epilepsy patients with a Class Engel IA or > IA outcome and compared to age-, sex- and handedness-matched healthy controls.

RESULTS

Increased metabolic connectivity was observed in the >IA compared to the IA group within the operated temporal lobe (respective clusters of 7.5 vs 3.3 cm³ and 2.6 cm³ vs 2.2 cm³ in left and right TLE), and to a lower extent with the contralateral temporal lobe (1.2 vs 0.7 cm³ and 1.7 cm³ vs 0.7 cm³ in left and right TLE). Seed correlations provided added value for the estimated individual performance of seizure outcome over the group comparisons in left TLE (AUC of 0.74 vs 0.67).

CONCLUSION

Metabolic connectivity is associated with outcome in surgically treated TLE with a strengthened epileptogenic connectome in patients with non-free-seizure outcomes. The added value of seed correlation analysis in left TLE underlines the importance of evaluating metabolic connectivity in network related diseases.

Interactions Between Brain 18F-FDG PET Metabolism and Hemodynamic Parameters at Different Ages of Life: Results From a Prospective Cross-Sectional Study

Brain 18F-FDG PET imaging is useful to characterize accelerated brain aging at a pre-symptomatic stage. This study aims to examine the interactions between brain glycolytic metabolism and hemodynamic parameters in different age groups.

Methods: A total of 72 patients (from 23 to 88 years of age, 38 women) without any cerebral diseases but with available cardiac, arterial peripheral, and central blood pressure measurements as well as arterial stiffness parameters obtained from brachial pressure and applanation tonometry and a brain 18F-FDG PET scan were prospectively included into this study. Quantitative voxel-to-voxel analyses were carried out to test for negative associations between brain glycolytic metabolism and individual hemodynamic parameters (p-voxel of &lt;0.001 for the whole population and &lt;0.005 for age groups).

Results: The heart rate parameter of the whole population showed the most extensive associations with brain metabolism (15,857 mm3, T-score: 5.1), predominantly affecting the frontal and temporal regions (69% of the volume). Heart rate for the younger age group, systolic and pulse pressure for the 41–60-year-old group, and diastolic pressure for the older group were most extensively associated with brain metabolism and mainly involved the fronto-temporal lobes (respective involvement of 52.8%, 60.9%, and 65.5%) which are also the regions implicated in accelerated brain aging.

Conclusion: This cross-sectional prospective study identified extensive associations between cerebral metabolism and hemodynamic parameters, indicating common aging mechanisms. Heart rate throughout adult life, systolic and pulse pressure parameters around middle age, and diastolic pressure parameters in older patients, suggest the existence of potentially therapeutic targets to prevent accelerated brain aging.

Long-Lasting Myocardial and Skeletal Muscle Damage Evidenced by Serial CMR During the First Year in COVID-19 Patients From the First Wave

Introduction

This observational CMR study aims to characterize left-ventricular (LV) damage, which may be specifically attributed to COVID-19 and is distant in time from the acute phase, through serial CMR performed during the first year in patients with no prior cardiac disease.

Methods

This study included consecutive patients without any prior history of cardiac disease but with a peak troponin-Ic &gt; 50 ng/ml at the time of the first COVID-wave. All had a CMR in the first months after the acute phase, and some had an additional CMR at the end of the first year to monitor LV function, remodeling, and abnormalities evocative of myositis and myocarditis - i.e., increased T1/T2 relaxation times, increased extracellular volume (ECV), and delayed contrast enhancement.

Results

Nineteen consecutively admitted COVID-19 patients (17 men, median age 66 [57–71] years) were included. Eight (42%) had hypertension, six (32%) were obese, and 16 (84%) had suffered an acute respiratory distress syndrome. The 1st CMR, recorded at a median 3.2 [interquartile range: 2.6–3.9] months from the troponin peak, showed (1) LV concentric remodeling in 12 patients (63%), (2) myocardial tissue abnormalities in 11 (58%), including 9 increased myocardial ECVs, and (3) 14 (74%) increased ECVs from shoulder skeletal muscles. The 2nd CMR, obtained at 11.1 [11.0–11.7] months from the troponin peak in 13 patients, showed unchanged LV function and remodeling but a return to normal or below the normal range for all ECVs of the myocardium and skeletal muscles.

Conclusion

Many patients with no history of cardiac disease but for whom an increase in blood troponin-Ic ascertained COVID-19 induced myocardial damage exhibited signs of persistent extracellular edema at a median 3-months from the troponin peak, affecting the myocardium and skeletal muscles, which resolved within a one-year time frame. Associations with long-COVID symptoms need to be investigated on a larger scale now.

Clinical Trial Registration

NCT04753762 on the ClinicalTrials.gov site.

Relationship Between Left Ventricular Ejection Fraction Variation and Systemic Vascular Resistance: A Prospective Cardiovascular Magnetic Resonance Study

Introduction: This cardiovascular magnetic resonance (CMR) study aims to determine whether changes in systemic vascular resistance (SVR), obtained from CMR flow sequences, might explain the significant long-term changes in left ventricular (LV) ejection fraction (EF) observed in subjects with no cardiac disease history. Methods: Cohort subjects without any known cardiac disease but with high rates of hypertension and obesity, underwent CMR with phase-contrast sequences both at baseline and at a median follow-up of 5.2 years. Longitudinal changes in EF were analyzed for any concomitant changes in blood pressure and vascular function, notably the indexed SVR given by the formula: mean brachial blood pressure / cardiac output x body surface area. Results: A total of 118 subjects (53 ± 12 years, 52% women) were included, 26% had hypertension, and 52% were obese. Eighteen (15%) had significant EF variations between baseline and follow-up (7 increased EF and 11 decreased EF). Longitudinal changes in EF were inversely related to concomitant changes in mean and diastolic blood pressures (p = 0.030 and p = 0.027, respectively) and much more significantly to SVR (p < 0.001). On average, these SVR changes were -8.08 ± 9.21 and +8.14 ± 8.28 mmHg.min.m².L^-1, respectively, in subjects with significant increases and decreases in EF, and 3.32 ± 7.53 mmHg.min.m².L^-1 in subjects with a stable EF (overall p < 0.001). Conclusions: Significant EF variations are not uncommon during the long-term CMR follow-up of populations with no evident health issues except for uncomplicated hypertension and obesity. However, most of these variations are linked to SVR changes and may therefore be unrelated to any intrinsic change in LV contractility. This underscores the benefits of specifically assessing LV afterload when EF is monitored in populations at risk of vascular dysfunction. Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT01716819 and NCT02430805.