Cardiac 2-D Shear Wave Imaging Using a New Dedicated Clinical Ultrasound System: A Phantom Study

OBJECTIVE

The purpose of this study was to assess cardiac shear wave imaging implemented in a new MACH 30 ultrasound machine (SuperSonic Imaging, Aix-en-Provence, France) and interfaced with a linear probe and a phased array probe, in comparison with a previously validated Aixplorer system connected to a linear probe (SuperSonic Imaging) using Elasticity QA phantoms (Models 039 and 049, CIRS Inc., Norfolk, VA, USA).

METHODS

Quantile-quantile plots were used for distribution agreement. The accuracy of stiffness measurement was assessed by the percentage error and the mean percentage error (MPE), and its homogeneity, by the standard deviation of the MPE. A p value <0.01 was considered to indicate statistical significance.

RESULTS

The accuracy of dedicated cardiac sequences for linear probes was similar for the two systems with an MPE of 8 ± 14% versus 20 ± 21% (p = not significant) with the SuperSonic MACH 30 and Aixplorer, respectively, and was influenced by target stiffness and location of the measurement in the field of view, but without drift over time. The optimal transthoracic cardiac probe workspace was located between 4 and 10 cm, with an MPE of 29.5 ± 25% compared with 93.3 ± 130% outside this area (p < 0.0001). In this area, stiffness below 20 kPa was significantly different from the reference (p < 0.0001). The sectorial probe revealed no MPE difference in any of the measurement areas, with no significant lateral or axial gradient.

CONCLUSION

The new Supersonic MACH 30 system upgraded with a sectorial probe and specific cardiac settings provided homogenous stiffness measurements, especially when operating at depths between 4 and 10 cm. These phantom results may be useful in designing future in vivo studies.

[18F]FDG PET-MR characterization of aortitis in the IL1rn-/- mouse model of giant-cell arteritis

BACKGROUND

Metabolic imaging is routinely used to demonstrate aortitis in patients with giant-cell arteritis. We aimed to investigate the preclinical model of aortitis in BALB/c IL1rn-/- mice using [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography-magnetic resonance (PET-MR), gamma counting and immunostaining. We used 15 first-generation specific and opportunistic pathogen-free (SOPF) 9-week-old IL1rn-/- mice, 15 wild-type BALB/cAnN mice and 5 s-generation specific pathogen-free (SPF) 9-week-old IL1rn-/-. Aortic [18F]FDG uptake was assessed as the target-to-background ratio (TBR) using time-of-flight MR angiography as vascular landmarks.

RESULTS

[18F]FDG uptake measured by PET or gamma counting was similar in the first-generation SOPF IL1rn-/- mice and the wild-type group (p > 0.05). However, the first-generation IL1rn-/- mice exhibited more interleukin-1β (p = 0.021)- and interleukin-6 (p = 0.019)-positive cells within the abdominal aorta than the wild-type mice. In addition, the second-generation SPF group exhibited significantly higher TBR (p = 0.0068) than the wild-type mice on the descending thoracic aorta, unlike the first-generation SOPF IL1rn-/- mice.

CONCLUSIONS

In addition to the involvement of interleukin-1β and -6 in IL1rn-/- mouse aortitis, this study seems to validate [18F]FDG PET-MR as a useful tool for noninvasive monitoring of aortitis in this preclinical model.

Measuring myocardial blood flow using dynamic myocardial perfusion SPECT: artifacts and pitfalls

Dynamic acquisition allows absolute quantification of myocardial perfusion and flow reserve, offering an alternative to overcome the potential limits of relative quantification, especially in patients with balanced multivessel coronary artery disease. SPECT myocardial perfusion is widely available, at lower cost than PET. Dynamic cardiac SPECT is now feasible and has the potential to be the next step of comprehensive perfusion imaging. In order to help nuclear cardiologists potentially interested in using dynamic perfusion SPECT, we sought to review the different steps of acquisition, processing, and reporting of dynamic SPECT studies in order to enlighten the potentially critical pitfalls and artifacts. Both patient-related and technical artifacts are discussed. Key parameters of the acquisition include pharmacological stress, radiopharmaceuticals, and injection device. When it comes to image processing, attention must be paid to image-derived input function, patient motion, and extra-cardiac activity. This review also mentions compartment models, cameras, and attenuation correction. Finally, published data enlighten some facets of dynamic cardiac SPECT while several issues remain. Harmonizing acquisition and quality control procedures will likely improve its performance and clinical strength.

Targeted Radiation Exposure Induces Accelerated Aortic Valve Remodeling in ApoE-/- Mice

Thoracic radiation therapy may result in accelerated atherosclerosis and in late aortic valve stenosis (AS). In this study, we assessed the feasibility of inducing radiation-induced AS using a targeted aortic valve irradiation (10 or 20 Grays) in two groups of C57Bl6/J (WT) and ApoE-/- mice compared to a control (no irradiation). Peak aortic jet velocity was evaluated by echocardiography to characterize AS. T2*-weighted magnetic resonance imaging after injection of MPIO-αVCAM-1 was used to examine aortic inflammation resulting from irradiation. A T2* signal void on valve leaflets and aortic sinus was considered positive. Valve remodeling and mineralization were assessed using von Kossa staining. Finally, the impact of radiation on cell viability and cycle from aortic human valvular interstitial cells (hVICs) was also assessed. The targeted aortic valve irradiation in ApoE-/- mice resulted in an AS characterized by an increase in peak aortic jet velocity associated with valve leaflet and aortic sinus remodeling, including mineralization process, at the 3-month follow-up. There was a linear correlation between histological findings and peak aortic jet velocity (r = 0.57, p < 0.01). In addition, irradiation was associated with aortic root inflammation, evidenced by molecular MR imaging (p < 0.01). No significant effect of radiation exposure was detected on WT animals. Radiation exposure did not affect hVICs viability and cell cycle. We conclude that targeted radiation exposure of the aortic valve in mice results in ApoE-/-, but not in WT, mice in an aortic valve remodeling mimicking the human lesions. This preclinical model could be a useful tool for future assessment of therapeutic interventions.

Modified Chevrel technique for abdominal closure in critically ill patients with abdominal hypertension and limited options for closure

Abdominal compartment syndrome is a potentially life-threatening condition seen in critically ill patients, and most often caused by acute pancreatitis, postoperative abdominal vascular thrombosis or mesenteric ischemia. A decompressive laparotomy is sometimes required, often resulting in hernias, and subsequent definitive wall closure is challenging.

AIM

This study aims to describe short term results after a modified Chevrel technique for midline laparotomies in patients witch abdominal hypertension.

MATERIALS AND METHODS

We performed a modified Chevrel as an abdominal closure technique in 9 patients between January 2016 and January 2022. All patients presented varying degrees of abdominal hypertension.

RESULTS

Nine patients were treated with new technique (6 male and 3 female), all of whom had conditions that precluded unfolding the contralateral side as a means for closure. The reasons for this were diverse, including presence of ileostomies, intraabdominal drainages, Kher tubes or an inverted T scar from previous transplant. The use of mesh was initially dismissed in 8 of the patients (88,9%) because they required subsequent abdominal surgeries or active infection. None of the patients developed a hernia, although two died 6 months after the procedure. Only one patient developed bulging. A decrease in intrabdominal pressure was achieved in all patients.

CONCLUSION

The modified Chevrel technique can be used as a closure option for midline laparotomies in cases where the entire abdominal wall cannot be used.

Left atrial strain quantified after myocardial infarction is associated with early left ventricular remodeling

BACKGROUND

Left ventricular remodeling (LVR) is common and associated with adverse outcome after ST-elevation myocardial infarction (STEMI). We aimed to investigate the association between left atrial (LA) mechanical function using speckle tracking imaging and early LVR at follow-up in STEMI patients.

METHODS

Baseline 3D thoracic echocardiograms were performed within 48 h following admission and at a median follow-up of 7 months after STEMI. A > 20% increase in the left ventricular (LV) end-diastolic volume compared to baseline at follow-up was defined as LVR. LA global longitudinal strain was evaluated for the reservoir, conduit, and contraction (LASct) phases.

RESULTS

A total of 121 patients without clinical heart failure (HF) were prospectively included, between June 2015 and October 2018 (age 58.3 ± 12.5 years, male 98 (81%)). Baseline and follow-up LV ejection fraction (LVEF) were 46.8% [41.0, 52.9] and 52.1% [45.8, 57.0] respectively (p < .001). Compared to other patients, those with LVR had significantly lower values of LASct at baseline (-7.4% [-10.1, -6.5] vs. -9.9% [-12.8, -8.1], p < .01), both on univariate and baseline LV volumes-adjusted analyses. Baseline LA strain for reservoir and conduit phases were not associated with significant LVR at follow-up. Intra- and interobserver analysis showed good reproducibility of LA strain.

CONCLUSIONS

Baseline LASct may help identifying patients without HF after STEMI who are at higher risk of further early LVR and subsequent HF and who may benefit from more intensive management.

Relationship between lifestyle factors and hypertension: a cross-sectional analysis from the Gubbio study

BACKGROUND

Hypertension (HTN) is a well-established and a major risk factor for cardiovascular disease. Lifestyle behaviours for its prevention and control are recommended within worldwide guidelines. Their relationship with HTN need more investigations.

AIM

We aimed to investigate the associations between lifestyle, anthropometric and biological measurements and BP in the Gubbio residential study.

METHODS

Cross-sectional analyses were performed using data from Gubbio study. Information concerning lifestyle factors were collected using self-reported questionnaire and were further completed with a baseline clinical examination and blood exams. Three BP measurements were performed following a standard protocol. Age-adjusted and multivariable logistic regressions were used to examine the relationships between lifestyle parameters and HTN separately for each sex. We used heterogeneity test to observe sex differences.

RESULTS

There were 3,183 persons included (48% men, 43 ± 17 years old). Mean systolic BP (SBP) was 119 ± 16 mmHg and 10.6% were hypertensives. Age [OR: 129.70 (95%CI: 18.57-905.79) in women and OR: 8.37 (95%CI: 4.01-17.48) (p < 0.0001) in men] and BMI [OR: 2.14 (95%CI: 1.32-3.46) (p = 0.006) in women and OR: 1.81 (95%CI: 1.05-3.12), p = 0.03 in men], were positively associated with SBP in both sexes. Serum uric acid [OR: 3.86 (95%CI: 2.03-7.26), p = 0.04] was positively associated with HTN in women while fasting blood glucose [OR: 3.04 (95%CI: 1.55-5.97), p < 0.001] were associated to HTN only in men.

DISCUSSION

In addition to age, BMI is associated with HTN in both sexes while sex differences were observed in the associations between serum uric acid, fasting blood glucose and HTN.

Quantitation of myocardial 99mTc-HMDP uptake with new SPECT/CT cadmium zinc telluride (CZT) camera in patients with transthyretin-related cardiac amyloidosis: Ready for clinical use?

BACKGROUND

The aim of this study was to investigate the feasibility of assessing absolute myocardial 99mTc-HMDP uptake in patients with suspected cardiac ATTR using SUV with a whole-body CZT SPECT-CT camera (DNM670CZT).

METHODS

Fifteen patients with suspected cardiac ATTR (Perugini ≥ 2) underwent a conventional 99mTc-HMDP planar imaging and a thoracic SPECT/CT using a DNM 670CZT. A control group consisted of 15 patients with negative scintigraphy (Perugini < 2). SUVmax (mg·L-1) and percentage of injected dose (%ID) were calculated in a cardiac volume of interest (VOI) encompassing the left ventricle. VOIs were also placed in the lung, the right pectoris major, and the sternum. A heart-to-lung SUVmax ratio (HLR) was calculated.

RESULTS

All ATTR patients demonstrated an increased cardiac HMDP SUVmax (12.2 ± 3.7 mg·L-1) vs controls (3.5 ± 1.2, P < .0001). Percentage of ID, pectoral uptake and HLR were significantly higher in the ATTR group (1.1 ± 0.3 vs 0.15 ± 0.8, P < .0001; 1.5 ± 0.3 vs 0.9 ± 0.3, P < .0001; 9.7 ± 3 vs 4.3 ± 2.2, P < .0001). Bone uptake was not statistically different between the two groups.

CONCLUSION

This study demonstrated the feasibility of quantitative 99mTc-HMDP SUVmax measurement using a whole-body SPECT/CT CZT camera in patients with suspected cardiac ATTR.

Quantification of myocardial blood flow by CZT-SPECT with motion correction and comparison with 15O-water PET

BACKGROUND

We compared quantification of MBF and myocardial flow reserve (MFR) with a 99mTc-sestamibi CZT-SPECT to 15O-water PET.

METHODS

SPECT MBF for thirty patients in the WATERDAY study was re-analyzed by QPET software with motion correction and optimal placement of the arterial input function. 15O-water PET MBF was re-quantified using dedicated software. Inter-operator variability was assessed using repeatability coefficients (RPC).

RESULTS

Significant correlations were observed between global (r = 0.91, P < 0.001) and regional MBF (r = 0.86, P < 0.001) with SPECT compared to PET. Global MBF (rest 0.95 vs 1.05 ml/min/g, P = 0.07; stress 2.62 vs 2.68 mL/min/g, P = 0.17) and MFR (2.65 vs 2.75, P = 0.86) were similar between SPECT and PET. Rest (0.81 vs 0.98 mL/min/g, P = 0.03) and stress MBF (1.98 vs 2.61 mL/min/g, P = 0.01) in right coronary artery (RCA) were lower with SPECT compared to PET. However, MFR in the RCA territory was similar (2.54 vs 2.77, P = 0.21). The SPECT-PET RPC for global MBFs and MFR were 0.95 mL/min/g and 0.94, with inter-observer RPC of 0.59 mL/min/g and 0.74, respectively.

CONCLUSIONS

MBF and MFR derived from CZT-SPECT with motion correction and optimal placement of the arterial input function showed good agreement with 15O-water PET, as well as low inter-operator variability.

First Follow-Up of Cardiac Amyloidosis Treated by Tafamidis, Evaluated by Absolute Quantification in Bone Scintigraphy

Assessment of absolute myocardial hydroxydimethylene diphosphonate–technetium-99m uptake using standardized uptake value with a single-photon emission computed tomography–computed tomography cadmium zinc telluride camera (Discovery NM/CT 670CZT, GE Healthcare, Chicago, Illinois) in a patient with cardiac transthyretin-related amyloidosis treated with tafamidis showed a decrease in hydroxydimethylene diphosphonate cardiac uptake. This imaging technique should be helpful in monitoring therapy and evaluating prognosis. (Level of Difficulty: Intermediate.)

Evaluation of the early-phase [18F]AV45 PET as an optimal surrogate of [18F]FDG PET in ageing and Alzheimer's clinical syndrome

Dual-phase [18F]AV45 positron emission tomography (PET) is highly promising in the assessment of neurodegenerative diseases, allowing to obtain information on both neurodegeneration (early-phase; eAV45) and amyloid deposition (late-phase; lAV45) which are highly complementary; yet eAV45 needs further evaluation. This study aims at validating eAV45 as an optimal proxy of [18F]FDG PET in a large mixed-population of healthy ageing and Alzheimer's clinical syndrome participants (n = 191) who had [18F]FDG PET, eAV45 and lAV45 scans. We found early time frame 0-4 min to give maximal correlation with [18F]FDG PET and minimal correlation with lAV45. Moreover, maximal overlap of [18F]FDG PET versus eAV45 associations with clinical diagnosis and cognition was obtained with pons scaling. Across reference regions, classification performance between clinical subgroups was similar for both eAV45 and [18F]FDG PET. These findings highlight the optimal use of eAV45 to assess neurodegeneration as a validated proxy of [18F]FDG PET. On top of this purpose, this study showed that combined [18F]AV45 PET dual-biomarker even outperformed [18F]FDG PET or lAV45 alone.

POS0338 STEROID-SPARING EFFECT OF ANAKINRA IN GIANT-CELL ARTERITIS: A CASE SERIES WITH CLINICAL, BIOLOGICAL AND ICONOGRAPHIC LONG-TERM ASSESSMENTS

Background:

The treatment of giant cell arteritis (GCA) relies on corticosteroids but is burdened by a high rate of relapses and adverse effects. Anti-interleukin-6 treatments show a clear benefit with a significant steroid-sparing effect, but late relapses occur after treatment discontinuation. In addition to interleukin-6, interleukin-1 also appears to play a significant role in GCA pathophysiology.

Objectives:

We report herein the efficacy of anakinra, an interleukin-1 receptor antagonist, in 6 GCA patients exhibiting corticosteroid dependence or resistance, specifically analyzing the outcome of aortitis in 4 of them, and including the long-term follow-up of 2 previously described patients (1).

Methods:

This retrospective study analyzed the cases of all GCA patients treated with anakinra from the French Study Group for Large Vessel Vasculitis.

Patients had to satisfy the following two criteria to be enrolled in this retrospective study. First, their diagnosis of GCA should be based on the fulfillment of at least 3 criteria of the American College of Rheumatology (ACR) for GCA or on the satisfaction of 2 of these criteria along with the demonstration of LVI on imaging. Second, patients should have received anakinra because of corticosteroid dependence or resistance.

Corticosteroid dependence was defined as ≥2 relapses or the combination of 2 of the following criteria: a daily dose of oral prednisone >20 mg/day (or 0.3 mg/kg) at 6 months; a daily dose of oral prednisone >10 mg/day (or 0.2 mg/kg) at 12 months; and/or a treatment maintained >24 months because of a relapsing disease course. Corticosteroid resistance was defined as persistent increased inflammatory parameters at month 3 despite a steroid dosage over 0.5 mg/kg.

Results:

After a median duration of anakinra therapy of 19 [18–32] months, all 6 patients exhibited complete clinical and biological remission. Among the 4 patients with large-vessel involvement, 2 had a disappearance of aortitis under anakinra, and 2 showed a decrease in vascular uptake. After a median follow-up of 56 [48–63] months, corticosteroids were discontinued in 4 patients, and corticosteroid dosage could be decreased to 5 mg/day in 2 patients. One patient relapsed 13 months after anakinra introduction in the context of increasing the daily anakinra injection interval to every 48 hours. Three patients experienced transient injection-site reactions, and 1 patient had pneumonia.

Figure 1.

Steroid dosages before and after the introduction of anakinra in 6 patients with giant-cell arteritis and corticosteroid dependence or resistance. The black arrow indicates the time of anakinra introduction.

Conclusion:

In this short series, anakinra appears to be an efficient and safe steroid-sparing agent in refractory GCA, with a possible beneficial effect on large-vessel involvement.

References:

[1]Ly K-H, Stirnemann J, Liozon E, Michel M, Fain O, Fauchais A-L. Interleukin-1 blockade in refractory giant cell arteritis. Joint Bone Spine 2014;81:76–8.

Disclosure of Interests:

Samuel Deshayes: None declared, Kim LY: None declared, Virginie Rieu: None declared, Gwénola Maigné: None declared, Nicolas Martin Silva: None declared, Alain Manrique: None declared, Jacques Monteil: None declared, Hubert de Boysson Speakers bureau: Roche-Chugai, Grant/research support from: Roche-Chugai, Achille Aouba Grant/research support from: SOBI

Steroid-sparing effect of anakinra in giant-cell arteritis: a case series with clinical, biological and iconographic long-term assessments

OBJECTIVES

The treatment of giant cell arteritis (GCA) relies on corticosteroids but is burdened by a high rate of relapses and adverse effects. Anti-interleukin-6 treatments show a clear benefit with a significant steroid-sparing effect, but late relapses occur after treatment discontinuation. In addition to interleukin-6, interleukin-1 also appears to play a significant role in GCA pathophysiology. We report herein the efficacy of anakinra, an interleukin-1 receptor antagonist, in 6 GCA patients exhibiting corticosteroid dependence or resistance, specifically analyzing the outcome of aortitis in 4 of them.

METHODS

This retrospective study analyzed the cases of all GCA patients treated with anakinra from the French Study Group for Large Vessel Vasculitis.

RESULTS

After a median duration of anakinra therapy of 19 [18-32] months, all 6 patients exhibited complete clinical and biological remission. Among the 4 patients with large-vessel involvement, 2 had a disappearance of aortitis under anakinra, and 2 showed a decrease in vascular uptake. After a median follow-up of 56 [48-63] months, corticosteroids were discontinued in 4 patients, and corticosteroid dosage could be decreased to 5 mg/day in 2 patients. One patient relapsed 13 months after anakinra introduction in the context of increasing the daily anakinra injection interval to every 48 hours. Three patients experienced transient injection-site reactions, and 1 patient had pneumonia.

CONCLUSION

In this short series, anakinra appears to be an efficient and safe steroid-sparing agent in refractory GCA, with a possible beneficial effect on large-vessel involvement.

TRPM4 Participates in Aldosterone-Salt-Induced Electrical Atrial Remodeling in Mice

Aldosterone plays a major role in atrial structural and electrical remodeling, in particular through Ca2+-transient perturbations and shortening of the action potential. The Ca2+-activated non-selective cation channel Transient Receptor Potential Melastatin 4 (TRPM4) participates in atrial action potential. The aim of our study was to elucidate the interactions between aldosterone and TRPM4 in atrial remodeling and arrhythmias susceptibility. Hyperaldosteronemia, combined with a high salt diet, was induced in mice by subcutaneously implanted osmotic pumps during 4 weeks, delivering aldosterone or physiological serum for control animals. The experiments were conducted in wild type animals (Trpm4+/+) as well as Trpm4 knock-out animals (Trpm4-/-). The atrial diameter measured by echocardiography was higher in Trpm4-/- compared to Trpm4+/+ animals, and hyperaldosteronemia-salt produced a dilatation in both groups. Action potentials duration and triggered arrhythmias were measured using intracellular microelectrodes on the isolated left atrium. Hyperaldosteronemia-salt prolong action potential in Trpm4-/- mice but had no effect on Trpm4+/+ mice. In the control group (no aldosterone-salt treatment), no triggered arrythmias were recorded in Trpm4+/+ mice, but a high level was detected in Trpm4-/- mice. Hyperaldosteronemia-salt enhanced the occurrence of arrhythmias (early as well as delayed-afterdepolarization) in Trpm4+/+ mice but decreased it in Trpm4-/- animals. Atrial connexin43 immunolabelling indicated their disorganization at the intercalated disks and a redistribution at the lateral side induced by hyperaldosteronemia-salt but also by Trpm4 disruption. In addition, hyperaldosteronemia-salt produced pronounced atrial endothelial thickening in both groups. Altogether, our results indicated that hyperaldosteronemia-salt and TRPM4 participate in atrial electrical and structural remodeling. It appears that TRPM4 is involved in aldosterone-induced atrial action potential shortening. In addition, TRPM4 may promote aldosterone-induced atrial arrhythmias, however, the underlying mechanisms remain to be explored.

Association of Sleep-Disordered Breathing With Alzheimer Disease Biomarkers in Community-Dwelling Older Adults: A Secondary Analysis of a Randomized Clinical Trial

Importance

Increasing evidence suggests that sleep-disordered breathing (SDB) increases the risk of developing Alzheimer clinical syndrome. However, the brain mechanisms underlying the link between SDB and Alzheimer disease are still unclear.

Objective

To determine which brain changes are associated with the presence of SDB in older individuals who are cognitively unimpaired, including changes in amyloid deposition, gray matter volume, perfusion, and glucose metabolism.

Design, Setting, and Participants

This cross-sectional study was conducted using data from the Age-Well randomized clinical trial of the Medit-Ageing European project, acquired between 2016 and 2018 at Cyceron Center in Caen, France. Community-dwelling older adults were assessed for eligibility and were enrolled in the Age-Well clinical trial if they did not meet medical or cognitive exclusion criteria and were willing to participate. Participants who completed a detailed neuropsychological assessment, polysomnography, a magnetic resonance imaging, and florbetapir and fluorodeoxyglucose positron emission tomography scans were included in the analyses.

Main Outcomes and Measures

Based on an apnea-hypopnea index cutoff of 15 events per hour, participants were classified as having SDB or not. Voxelwise between-group comparisons were performed for each neuroimaging modality, and secondary analyses aimed at identifying which SDB parameter (sleep fragmentation, hypoxia severity, or frequency of respiratory disturbances) best explained the observed brain changes and assessing whether SDB severity and/or SDB-associated brain changes are associated with cognitive and behavioral changes.

Results

Of 157 participants initially assessed, 137 were enrolled in the Age-Well clinical trial, and 127 were analyzed in this study. The mean (SD) age of the 127 participants was 69.1 (3.9) years, and 80 (63.0%) were women. Participants with SDB showed greater amyloid burden (t114 = 4.51; familywise error-corrected P = .04; Cohen d, 0.83), gray matter volume (t119 = 4.12; familywise error-corrected P = .04; Cohen d, 0.75), perfusion (t116 = 4.62; familywise error-corrected P = .001; Cohen d, 0.86), and metabolism (t79 = 4.63; familywise error-corrected P = .001; Cohen d, 1.04), overlapping mainly over the posterior cingulate cortex and precuneus. No association was found with cognition, self-reported cognitive and sleep difficulties, or excessive daytime sleepiness symptoms.

Conclusions and Relevance

The SDB-associated brain changes in older adults who are cognitively unimpaired include greater amyloid deposition and neuronal activity in Alzheimer disease-sensitive brain regions, notably the posterior cingulate cortex and precuneus. These results support the need to screen and treat for SDB, especially in asymptomatic older populations, to reduce Alzheimer disease risk.

Trial Registration

ClinicalTrials.gov Identifier: NCT02977819.

Impaired left atrial function in adults and adolescents with corrected aortic coarctation

This study examined the left atrial (LA) function using two-dimensional (2D) strain analysis after aortic coarctation (CoA) repair, as well as relationships between LA function and patient characteristics, especially aortic arch anatomy. 56 patients (34 males, age: 31 ± 16 years) with CoA repair (46 post 'end-to-end anastomosis/subclavian flap') and 56 controls were studied. 2D strain imaging was performed to assess left ventricular (LV) and LA functions including peak-positive LA strain, early and late diastolic LA strains, and global longitudinal (LV-GLS) and circumferential (LV-GCS) strains. LA dysfunction (LAD) was defined as a peak-positive LA strain value lower than the mean value of the control group minus 2 SDs. Peak-positive LA strain, early and late diastolic LA strains, and LV-GLS were significantly lower in the CoA group while LV-GCS did not differ. No significant correlation was found between LA strain and either current age, age at initial repair, or blood pressure; Ea and LV-GLS were moderately correlated to peak-positive LA strain (r = 0.49, p < 0.001 and r =  - 0.55, p < 0.001, respectively). 23 CoA patients (41%) presented LAD (abnormal peak-positive LA strain < 25%). Among patients who underwent end-to-end anastomosis/subclavian flap, those with a non-romanesque aortic arch anatomy exhibited a significantly lower peak-positive LA strain. Ischemic stroke and atrial arrhythmia were more frequent in CoA patients with LAD. Our findings suggest that LAD may be prevalent late after CoA repair. Postoperative aortic arch anatomy may impact peak-positive LA strain.

Comparison of the dyssynchrony parameters recorded with gated SPECT in ischemic cardiomyopathy according to their repeatability at rest and to their ability to detect a synchrony reserve under dobutamine infusion

BACKGROUND

This study aimed to determine whether the repeatability of dyssynchrony assessment using gated myocardial perfusion SPECT (GSPECT) allows the detection of synchrony reserve during low-dose dobutamine infusion.

METHODS AND RESULTS

Sixty-one patients with ischemic cardiomyopathy and LV ejection fraction < 50% were prospectively included in 10 centers. Each patient underwent two consecutive rest GSPECT with 99mTc-labeled tracer (either tetrofosmin or sestamibi) to assess the repeatability of LV function and dyssynchrony parameters, followed by a GSECT acquisition during low-dose dobutamine infusion. LV dyssynchrony was assessed using QGS software through histogram bandwidth (BW), standard deviation of the phase (SD), and entropy. Repeatability was assessed with Lin's concordance correlation coefficient (CCC). Entropy showed a higher CCC (0.80) compared to BW (0.68) and SD (0.75). On average, dobutamine infusion yielded to improve both BW (P = .049) and entropy (P = .04) although significant improvements, setting outside the 95% confidence interval of the repeatability analysis, were documented in only 6 and 4 patients for BW and entropy, respectively.

CONCLUSIONS

A synchrony reserve may be documented in patients with ischemic cardiomyopathy through the recording of BW and entropy with low-dose dobutamine GSPECT, with the additional advantage of a higher repeatability for entropy.

Definition of left ventricular remodelling following ST-elevation myocardial infarction: a systematic review of cardiac magnetic resonance studies

Background/Introduction

An increase in left ventricular volumes between baseline and follow-up imaging is the main criteria for the quantification of left ventricular remodeling after ST-elevation myocardial infarction, but without consensual definition.

Purpose

We aimed to review the criterion used for the definition of left ventricular remodeling based on cardiac magnetic resonance imaging in studies including patients with ST-elevation myocardial infarction.

Methods

A systematic literature search was conducted using MEDLINE and the Cochrane Library from January 2010 to August 2019. Thirty-seven studies involving a total of 4209 patients were included.

Results

The median age of the patients was 59 years, 82% were male, and 93% underwent primary percutaneous coronary intervention. The median follow-up duration was 6 months (range, 3–12), and the second cardiac magnetic resonance session was performed at 6 months in 14 (38%) studies. Among these studies, 30 (81%) used a cut-off value for defining left ventricular remodeling, with a pooled left ventricular remodeling prevalence estimate of 22.8%, 95%-CI[19.4%-26.7%], and a major between-study heterogeneity (I2=82%). The seven remaining studies (19%) defined left ventricular remodeling as a continuous variable. A 20% increase in end-diastolic volumes or a 15% increase in end-systolic volumes between a baseline and a follow-up cardiac magnetic resonance imaging were the two most common criterion (13 [35%] and 9 [24%] studies, respectively). Seven studies used both end-diastolic and end-systolic vleft ventricular volumes.

Conclusion(s)

The definition of left ventricular remodeling using cardiac magnetic resonance following ST-elevation myocardial infarction is highly variable, among studies including highly selected patients. The most frequent left ventricular remodeling criterion were a 20% increase in end-diastolic volumes or a 15% increase in end-systolic volumes. A composite cut-off value of a 12% to 15% increase in end-systolic volume and a 12% to 20% increase in end-diastolic volume using a follow-up cardiac magnetic resonance imaging 1 to 3 months after myocardial infarction might be proposed as a consensual cut-off for defining adverse left ventricular remodeling for future large-sized, prospective studies with serial cardiac magnetic resonance imaging and long-term follow-up in unselected patients.

Funding Acknowledgement

Type of funding source: None

Left atrial strain is associated with left ventricular remodeling in patients with ST-elevation myocardial infarction

Background/Introduction

Left ventricular remodeling (LVR) remains common and is associated with outcomes in patients with ST-elevation myocardial infarction (STEMI). Left atrial (LA) volume has been described as a predictor of outcomes in the latter population.

Purpose

To investigate the association between LA mechanical function using speckle tracking imaging and LVR at follow-up in STEMI patients.

Methods

Baseline 3D transthoracic echocardiograms were performed in 121 STEMI patients. LA global longitudinal strain was reported separately for the reservoir (LASr), conduit (LAScd), and contraction (LASct) phases. Follow-up echocardiograms were performed at 6 months.

Results

Mean age was 58.3±12.5 years and 98 (81%) were men. Baseline left ventricular ejection fraction (LVEF) was 46.8% [41.0, 52.9] and significantly improved to 52.1% [45.8, 57.0] at follow-up, (p&lt;0.001). A lower LASct was associated with a significant dilation of left ventricle at follow-up (%end-diastolic volume increase: −1.9% [−11.0, 15.2] in the two higher LASct tertiles group vs. 19.2% [5.0, 34.3] in the lower LASct tertile group, p=0.001). A higher %end-systolic volume increase at follow-up was associated with lower LASct as well: 12.6% [−16.2, 39.8] in the lower LASct group vs. −6.8% [−23.6, 14.4] in the two higher LASct tertiles group (p=0.004). Regarding LVEF, a low LVEF at follow-up was associated with the worst tertile of all LA strains (LASr, p=0.002; LAScd, p=0.01 and LASct, p=0.01).

Conclusion(s)

The three components of baseline LA strain were associated with LVEF at follow-up in patients with STEMI. Some of these components were also significantly associated with lower LVEF at baseline or predictive of a significant increase in left ventricular volumes during follow-up, indicating LVR.

Funding Acknowledgement

Type of funding source: None

Serum neprilysin levels are associated with myocardial stunning after ST-elevation myocardial infarction

Background/Introduction

Left ventricular remodeling following ST-elevation myocardial infarction (STEMI) is associated with poor outcome. Neprilysin inhibition leads to improved outcome in patients with altered left ventricular ejection fraction (LVEF).

Purpose

We aimed to assess the association between serum levels of neprilysin and left ventricular (LV) volumes, function and remodeling in STEMI patients with successful myocardial reperfusion.

Methods

Sixty-eight patients were admitted for STEMI and had both plasma neprilysin measurement at baseline and 3D transthoracic echocardiogram at baseline and at follow-up (7 months). We compared 3 groups: a group with a low-level of plasma neprilysin (&lt;125 pg/mL, i.e. the lower limit of detection of the assay, 38 patients) and the two other groups were defined as being below or above the median value of the remaining samples (15 patients each).

Results

Median age was 58.5±12.8 years and 56 (82.4%) were men. Median LVEF was 45.0±8.5%. Baseline characteristics were comparable among groups. At baseline there was a non-significant trend towards lower end-diastolic volume (p=0.07) but significantly lower LVEF in the high neprilysin group (46.4±8.3%, 47.1±8.1% and 39.1±6.9%, p&lt;0.01). At follow-up, the magnitude of LVEF increase was significantly more important in the high neprilysin group compared to the other groups (p=0.022 for relative change in LVEF and 6.6±7.3%, 3.6±9.0% and 11.3±8.4%, p=0.031 for absolute change in LVEF) resulting in similar LVEF levels at follow-up between all groups (53.0±8.9%, 50.6±9.7% and 50.4±9.9%, p=0.55).

Conclusion(s)

Initial high neprilysin levels may identify patients with stunned myocardium early after STEMI, with a recovery of contractility leading to improved LVEF at follow-up.

Funding Acknowledgement

Type of funding source: None

TRPM4 non-selective cation channel in human atrial fibroblast growth

Cardiac fibroblasts play an important role in cardiac matrix turnover and are involved in cardiac fibrosis development. Ca²⁺ is a driving belt in this phenomenon. This study evaluates the functional expression and contribution of the Ca²⁺-activated channel TRPM4 in atrial fibroblast phenotype. Molecular and electrophysiological investigations were conducted in human atrial fibroblasts in primary culture and in atrial fibroblasts obtained from wild-type and transgenic mice with disrupted Trpm4 gene (Trpm4^-/-). A typical TRPM4 current was recorded on human cells (equal selectivity for Na⁺ and K⁺, activation by internal Ca²⁺, voltage sensitivity, conductance of 23.2 pS, inhibition by 9-phenanthrol (IC₅₀ = 6.1 × 10^-6 mol L^-1)). Its detection rate was 13% on patches at days 2-4 in culture but raised to 100% on patches at day 28. By the same time, a cell growth was observed. This growth was smaller when cells were maintained in the presence of 9-phenanthrol. Similar cell growth was measured on wild-type mice atrial fibroblasts during culture. However, this growth was minimized on Trpm4^-/- mice fibroblasts compared to control animals. In addition, the expression of alpha smooth muscle actin increased during culture of atrial fibroblasts from wild-type mice. This was not observed in Trpm4^-/- mice fibroblasts. It is concluded that TRPM4 participates in fibroblast growth and could thus be involved in cardiac fibrosis.

First comparison of performances between the new whole-body cadmium-zinc-telluride SPECT-CT camera and a dedicated cardiac CZT camera for myocardial perfusion imaging: Analysis of phantom and patients

BACKGROUND

Dedicated cardiac Cadmium-zinc-telluride (CZT) cameras show superior performances compared with Anger systems, particularly in terms of spatial resolution and count sensitivity. This study evaluated the performances of a new polyvalent whole body CZT camera (DNM 670CZT) compared with a cardiac dedicated CZT camera (DNM 530c) for myocardial perfusion SPECT.

METHODS

The spatial resolution was evaluated with three linear sources filled with 99mTc. We used a cardiac phantom to evaluate count sensitivity, sharpness index, contrast-to-noise ratio, wall thickness, non-uniformity index, perfusion scores and ventricle volumes for both cameras. The impact of matrix size, and acquisition time was investigated. Concordance between the two cameras was evaluated in patients using QPS/QGS software for quantitative segmental perfusion, motion and thickness scores.

RESULTS

The spatial resolution was identical with the two cameras. Count sensitivity of the DNM 670CZT was twofold lower compared with the DNM 530c, leading to lower sharpness index and contrast-to-noise ratio. The wall thickness and the myocardial volumes were similar. Visual and quantitative assessments of the perfusion patterns have shown a good concordance of the two cameras on phantoms and in patients.

CONCLUSION

This study demonstrated the feasibility of myocardial perfusion SPECT imaging using the new whole-body DNM 670CZT camera.

Serum neprilysin levels are associated with myocardial stunning after ST-elevation myocardial infarction

Background

Left ventricular remodeling following ST-elevation myocardial infarction (STEMI) is associated with poor outcome, including heart failure (HF). Neprilysin inhibition leads to improved outcome in patients with altered left ventricular ejection fraction (LVEF).

Methods

We aimed to assess the association between serum levels of neprilysin and left ventricular (LV) volumes, function and remodeling in STEMI patients with successful myocardial reperfusion and no clinical sign of HF. Sixty-eight patients were admitted for STEMI and had both plasma neprilysin measurement at baseline and 3D transthoracic echocardiogram at baseline and after a median follow-up of 7 months. We compared 3 groups: a group with a low-level of plasma neprilysin (< 125 pg/mL, i.e. the lower limit of detection of the assay) and the two other groups were defined as being below or above the median value of the remaining samples.

Results

Median age was 58.5 ± 12.8 years and 56 (82.4%) were men. Median LVEF was 45.0 ± 8.5%. Baseline characteristics were comparable between groups (low-level of neprilysin group [≤125 pg/mL, n = 38], medium-level of neprilysin group [126–450 pg/mL, n = 15] and a high-level group [> 450 pg/mL, n = 15]). At baseline there was a non-significant trend towards lower end-diastolic volume (p = 0.07) but significantly lower LVEF in the high neprilysin group (46.4 ± 8.3%, 47.1 ± 8.1% and 39.1 ± 6.9%, p < 0.01). At follow-up, the magnitude of LVEF increase was significantly more important in the high neprilysin group compared to the other groups (p = 0.022 for relative change in LVEF and 6.6 ± 7.3%, 3.6 ± 9.0% and 11.3 ± 8.4%, p = 0.031 for absolute change in LVEF) resulting in similar LVEF levels at follow-up between all groups (53.0 ± 8.9%, 50.6 ± 9.7% and 50.4 ± 9.9%, p = 0.55).

Conclusions

Initial high neprilysin levels may identify patients with stunned myocardium early after STEMI, with a recovery of contractility leading to improved LVEF at follow-up. Future studies will have to assess the role of neprilysin in the setting of STEMI and the potential benefit of its blockade.

Usefulness of Cardiac Magnetic Resonance Imaging in Aortic Stenosis

The objective of this review is to provide an overview of the role of cardiac magnetic resonance (CMR) in aortic stenosis (AS). Although CMR is undeniably the gold standard for assessing left ventricular volume, mass, and function, the assessment of the left ventricular repercussions of AS by CMR is not routinely performed in clinical practice, and its role in evaluating and quantifying AS is not yet well established. CMR is an imaging modality integrating myocardial function and disease, which could be particularly useful in a pathology like AS that should be considered as a global myocardial disease rather than an isolated valve disease. In this review, we discuss the emerging potential of CMR for the diagnosis and prognosis of AS. We detail its utility for studying all aspects of AS, including valve anatomy, flow quantification, left ventricular volumes, mass, remodeling, and function, tissue mapping, and 4-dimensional flow magnetic resonance imaging. We also discuss different clinical situations where CMR could be useful in AS, for example, in low-flow low-gradient AS to confirm the low-flow state and to understand the reason for the left ventricular dysfunction or when there is a suspicion of associated cardiac amyloidosis.

Usefulness of a personalized algorithm-based discharge checklist in patients hospitalized for acute heart failure

Aims

The aim of this study is to evaluate the usefulness of a personalized discharge checklist (PCL) based on simple baseline characteristics on mortality, readmission for heart failure (HF), and quality of care in patients hospitalized for acute HF.

Methods and results

We designed an algorithm to generate PCL, based on 2016 HF European Society of Cardiology Guidelines and the screening of common comorbidities in elderly HF patients. We prospectively included 139 patients hospitalized for HF from May 2018 to October 2018. A PCL was fulfilled for each patient at admission and 24 to 48 hours before the planned discharge. A control cohort of 182 consecutive patients was retrospectively included from May 2017 to October 2017. The primary composite endpoint was mortality or readmission for HF at 6 months. The secondary endpoints were mortality, readmission for HF, and quality of care (evidence‐based medications, management of HF comorbidities, and planned care plan). There was no difference among baseline characteristics between PCL and control cohorts; mean age was 78.1 ± 12.2 vs. 79.0 ± 12.5 years old (P = 0.46) and 61 patients (43.9%) vs. 63 (34.6%) had HF with left ventricular ejection fraction (LVEF) <40% (P = 0.24). During the 6 month follow‐up period, 59 patients (42.4%) reached the primary endpoint in the PCL cohort vs. 92 patients (50.5%) in the control cohort [hazard ratio (HR): 0.79, 95% confidence interval (CI) (0.57–1.09), P = 0.15]. Subgroup analysis including only patients with either altered (<40%) or mid‐range or preserved (≥40%) LVEF showed no significant difference among groups. There was a non‐significant trend toward a reduction in HF readmission rate in the PCL group [38 patients (27.3%) vs. 64 patients (35.2%), HR: 0.73, 95%CI (0.49–1.09), P = 0.13]. There was no difference regarding survival or the use of evidence‐based medications. A higher proportion of patients were screened and treated for iron and vitamin D deficiencies (53.2% vs. 35.7%, P < 0.01 and 73.4% vs. 29.7%, P < 0.01, respectively), as well as malnutrition supplemented in the PCL group. There was a higher referral to HF follow‐up programme in the PCL group but not to telemedicine or cardiac rehabilitation programs.

Conclusions

In this preliminary study, the use of a PCL did not improve outcomes at 6 months in patients hospitalized for acute HF. There was a non‐significant trend towards a reduction in HF readmission rate in the PCL group. In addition, the management of HF comorbidities was significantly improved by PCL with a better referral to follow‐up programme. A multicentre study is warranted to assess the usefulness of a simple costless personalized checklist in a large HF patients' population.

Current Status of Myocardial Perfusion Imaging With New SPECT/CT Cameras

Myocardial perfusion imaging (MPI) with Single-Photon Emission Computed Tomography (SPECT) has a major role in the management of coronary artery disease. Recent technological advances regarding SPECT detectors with the use of solid-state detectors has allowed for improved imaging quality since a decade with dramatic dose and/or time reduction of imaging protocols due to improved sensitivity and spatial resolution, and is now performed as a routine exam. Interestingly, this new technology has modified our everyday practice, from acquisition protocols (low dose and ultra-fast protocols) to image semiology. Numerous studies have shown how these technical advances have allowed for improved patient management, with similar or improved diagnostic and prognostic information derived from MPI. These improvements have also led to the straightforward implementation of myocardial blood flow measurement. This article reviews the current status of MPI using new SPECT and SPECT/CT cameras.

P1393 Intervendor difference in global and regional 2D speckle tracking strain. comparison against cMR tagging

Funding Acknowledgements

Fondation de Recherche Scientifique Belge FRSM PDR 19488731

BACKGROUND

2D-speckle-tracking (ST) echocardiography is currently widely used for estimation of global (G) and regional myocardial deformation. In previous works, we showed good correlation between global longitudinal (LS) and circumferential strain (CS) from one 2DST vendor with cMR-Tagging, however with significant bias between both methods. Also, we found poorer agreement between 2DST and cMR-Tagging on regional basis. However it is unknown how 2DST from other vendors would comparte to cMR tagging.

PURPOSE

To asssess vendor differences in global and regional strain assessment and compare 1) the agreement of 2 different 2DST softwares for global and regional LS and CS among each other and against cMR-Tagging as reference; and 2) the accuracy of both softwares to detect infarcted segments.

METHODS

100 subjects with different cardiac disease (among which 31 with chronic infarct) underwent 2DST and tagging and LGE cMR on the same day. Global and regional CS (16 AHA segments) and LS (18 AHA segments) was computed using 2 different ST vendor softwares and compared to cMR-Tagging with HARP. Accuracy of regional 2D-ST by both vendors to detect infarcted segments (ie &gt;75% transmurality of late gadolinium) was compared using ROC analysis.

RESULTS

Global LS (ICC = 0.87) and CS 2DST (ICC = 0.83, p &lt; 0.001) agreed well between both vendors, but GCS values of vendor2 were significantly greater than that of vendor 1. Also we fond good correlation between ST of both vendors and cMR-Tagging for GLS (ICC = 0.80 and ICC = 0.69 for vendor 1 and 2 respectively) and GCS (ICC = 0.64 and ICC = 0.50 for vendor 1 and 2 respectively). Bias for GLS (-4.6 ± 2.9% and -6.1 ± 3.8% for vendor 1 and 2 respectively) vs cMR-Tagging was similar, however GCS of vendor 2 had higher bias vs cMR-Tagging (-16.0 ± 8.5%) than vendor 1 (-5.1 ± 5.8%).

Agreement for regional strains is shown in the figure below. Overall, regional LS and CS agreed adequately among both vendors. Agreement of regional LS and CS vs cMR-tagging was slightly better for vendor 1, with less bias than for vendor 2, and disagreement was similarly located (ie agreement with cMR-Tagging for LS in inferolateral inferior and inferoseptal basal segments). The predictive accuracy of regional CS and LS for detecting segments with infarct was higher for vendor 2 (AUC 0.76 and 0.68) than for vendor 1 (AUC 0.70 and 0.63) .

CONCLUSION

GLS agreed well among both vendors and with cMR-Tagging, confirming the universal validity of this measurement. However vendor 2 provided significantly greater GCS values and had higher bias against cMR-Tagging than vendor 1. On regional basis CS and LS agreed moderately well among both vendors, however vendor 2 agreed less with cMR-Tagging than vendor 1, but astoundingly had higher diagnostic accuracy for detecting infarct. Overall this findings call for further efforts in standardization of 2DST CS and regional strain.

Abstract P1393 Figure.

Quantification of myocardial 99mTc-labeled bisphosphonate uptake with cadmium zinc telluride camera in patients with transthyretin-related cardiac amyloidosis

PURPOSE

We aimed to compare different methods for semi-quantitative analysis of cardiac retention of bone tracers in patients with cardiac transthyretin amyloidosis (ATTR).

METHODS

Data from 67 patients with ATTR who underwent both conventional whole-body scan and a CZT myocardial SPECT (DSPECT, Spectrum Dynamics) 3 h after injection of ^99mTc-labeled bone tracer were analyzed. Visual scoring of cardiac retention was performed on whole-body scan according to Perugini 4-point grading system from 0 (no uptake) to 3 (strong cardiac uptake with mild/absent bone uptake). A planar heart-to-background (H:B) ratio was calculated using whole-body scan (wb-H:B). CZT SPECT was quantified using three methods: planar H:B ratio calculated from anterior reprojection (ant-H:B), left anterior oblique reprojection (LAO-H:B), and 3D-H:B ratio calculated from transaxial slices as mean counts in a VOI encompassing the heart divided by background VOI in the contralateral lung. Interventricular septal thickness was obtained using echocardiography.

RESULTS

H:Bs obtained from planar and reprojected data were not statistically different (wb-H:B, 2.05 ± 0.64, ant-H:B, 1.97 ± 0.61, LAO-H:B, 2.06 ± 0.64, all p = ns). However, 3D-H:B was increased compared to planar H:Bs (3D-H:B, 4.06 ± 1.77, all p < 0.0001 vs. wb-H:B, ant-H:B, and LAO-H:B). Bland-Altman plots demonstrated that the difference between 3D and planar H:Bs increased with the mean value of myocardial uptake. 3D-H:B was best correlated to septal thickness (r = 0.45, p < 0.001). Finally, abnormal right ventricular uptake was associated with higher values of cardiac retention.

CONCLUSION

3D semi-quantitative analysis of CZT SPECT optimized the assessment of ^99mTc-labeled bone tracer myocardial uptake in patients with cardiac amyloidosis.

Molecular imaging of endothelial activation and mineralization in a mouse model of accelerated atherosclerosis

Purpose

Preclinical imaging of endothelial activation and mineralization using both positron emission tomography (PET) and magnetic resonance (MR) remains scarce.

Procedures

A group of uremic ApoE^−/− (Ur), non-uremic ApoE^−/− (NUr), and control C57Bl/6 J mice (Ctl) were investigated. Mineralization process was assessed using sodium fluoride ([18F]NaF) PET, and MR imaging combined with intravenous injection of MPIO-αVCAM-1 was used to evaluate endothelial activation. Micro- and macrocalcifications were evaluated by flame atomic absorption spectroscopy and von Kossa staining, respectively.

Results

Ur mice showed an active and sustained mineralization process compared to Ctl mice (p = 0.002) using [18F]NaF PET imaging. Calcium plasma level was increased in Ur (2.54 ± 0.09 mM, n = 17) compared to NUr and Ctl mice (2.24 ± 0.01, n = 22, and 2.14 ± 0.02, n = 27, respectively; p < 0.0001). Likewise, vascular calcium content was increased in Ur (0.51 ± 0.06 μg Ca²⁺ per milligram of dry weight aorta, n = 11) compared to NUr (0.27 ± 0.05, n = 9, p = 0.013) and Ctl (0.28 ± 0.05, n = 11, p = 0.014). Ur mice also had a higher inflammatory state using MPIO-αVCAM-1 MR (p global = 0.01, post hoc analysis Ur vs. Ctl p = 0.003) associated with increased VCAM-1 expression (p global = 0.02). Aortic remodeling at the level of the brachiocephalic trunk, brachiocephalic trunk itself, and aortic arch in Ur mice was also demonstrated using MR.

Conclusions

Preclinical molecular imaging allowed in vivo characterization of the early phase of atherosclerosis. [18F]NaF PET showed early and sustained vascular mineralization in uremic ApoE^−/− mice. MPIO-αVCAM-1 MR imaging demonstrated aortic endothelial activation, predominantly in segments with vascular remodeling.

Performance Evaluation of a Dedicated Preclinical PET/CT System for the Assessment of Mineralization Process in a Mouse Model of Atherosclerosis

PURPOSE

The purpose of this study was to assess the impact of positron emission tomography/X-ray computed tomography (PET/CT) acquisition and reconstruction parameters on the assessment of mineralization process in a mouse model of atherosclerosis.

PROCEDURES

All experiments were performed on a dedicated preclinical PET/CT system. CT was evaluated using five acquisition configurations using both a tungsten wire phantom for in-plane resolution assessment and a bar pattern phantom for cross-plane resolution. Furthermore, the radiation dose of these acquisition configurations was calculated. The PET system was assessed using longitudinal line sources to determine the optimal reconstruction parameters by measuring central resolution and its coefficient of variation. An in vivo PET study was performed using uremic ApoE^-/-, non-uremic ApoE^-/-, and control mice to evaluate optimal PET reconstruction parameters for the detection of sodium [¹⁸F]fluoride (Na[¹⁸F]F) aortic uptake and for quantitative measurement of Na[¹⁸F]F bone influx (Ki) with a Patlak analysis.

RESULTS

For CT, the use of 1 × 1 and 2 × 2 binning detector mode increased both in-plane and cross-plane resolution. However, resolution improvement (163 to 62 μm for in-plane resolution) was associated with an important radiation dose increase (1.67 to 32.78 Gy). With PET, 3D-ordered subset expectation maximization (3D-OSEM) algorithm increased the central resolution compared to filtered back projection (1.42 ± 0.35 mm vs. 1.91 ± 0.08, p < 0.001). The use of 3D-OSEM with eight iterations and a zoom factor 2 yielded optimal PET resolution for preclinical study (FWHM = 0.98 mm). These PET reconstruction parameters allowed the detection of Na[¹⁸F]F aortic uptake in 3/14 ApoE^-/- mice and demonstrated a decreased Ki in uremic ApoE^-/- compared to non-uremic ApoE^-/- and control mice (p < 0.006).

CONCLUSIONS

Optimizing reconstruction parameters significantly impacted on the assessment of mineralization process in a preclinical model of accelerated atherosclerosis using Na[¹⁸F]F PET. In addition, improving the CT resolution was associated with a dramatic radiation dose increase.

Comparative Performances of Dipyridamole and Regadenoson to Detect Myocardial Ischemia using Cardiac Cadmium-Zinc-Telluride Single-Photon Emission Computerized Tomography

Objective:

We evaluated the relative performances of dipyridamole (Dip) and regadenoson (Reg) in a cohort of patients referred for coronary artery disease diagnosis or follow-up using myocardial perfusion imaging.

Materials and Methods:

We retrospectively included 515 consecutive patients referred for ^99mTc-sestamibi myocardial perfusion single-photon emission computerized tomography (SPECT) on a cadmium-zinc-telluride (CZT) camera after pharmacologic stress. About three quarters (n = 391, 76%) received Dip. Reg was administrated to patients with chronical respiratory disease or with body mass index (BMI) over 38 kg/m² (n = 124, 24%). Patients with an abnormal stress scan (92%) underwent a rest imaging on the same day. Qualitative interpretation of perfusion images was achieved using QPS software, and the ischemic area was assessed using the 17-segment model. In patients undergoing a stress-rest protocol, perfusion polar plots were postprocessed using automated in-house software to quantify the extension, intensity, and location of the reversible perfusion defect. Statistical comparison between groups was performed using univariate and multivariate analysis.

Results:

Qualitative analysis concluded to myocardial ischemia in 70% of the patients (69% in the Dip group, 76% in the Reg group, P = ns). In those patients, the number of involved segments (Dip 2.5 ± 1.6, Reg 2.7 ± 1.6, P = ns) and the proportion of patients with an ischemic area larger than two segments (Dip 30%, Reg 37%, P = ns) were comparable. Automated quantification of the reversible perfusion defect demonstrated similar defect extension, intensity, and severity in the two groups. Defect location was identical at the myocardial segment and vascular territory scales.

Conclusions:

Reg and Dip showed equal performances for ischemic burden characterization using myocardial CZT SPECT.

First assessment of simultaneous dual isotope (123I/99mTc) cardiac SPECT on two different CZT cameras: A phantom study

BACKGROUND

We studied the impact of simultaneous dual-isotope acquisition on 123I/99mTc mismatch assessment using two CZT cameras (DNM 530c, GE Healthcare and DSPECT, Biosensors International).

METHODS

We used an anthropomorphic torso phantom (respectively filled with a solution of 123I alone, 99mTc alone, and a mixture of 123I and 99mTc) and its cardiac insert with two defects mimicking two matched and mismatched defects. Mismatch extent and reconstructed image contrast were evaluated.

RESULTS

The acquisition mode (single vs dual) significantly impacted (i) 99mTc (but not 123I) reconstructed segmental activities using both camera (P < .001), and (ii) image contrast (using 123I and DNM 530c, P < .0001; and using both 123I and 99mTc with DSPECT, P < .0001). However, the defect and mismatch size were not impacted by the type of acquisition. With both DNM 530c and DSPECT, Lin's concordance correlation coefficient and Bland-Altman analysis demonstrated an almost perfect concordance and agreement between single- and simultaneous dual-isotope segmental activity (123I and 99mTc).

CONCLUSIONS

This study found no impact of the acquisition mode (single vs dual) or the type of camera (DSPECT vs DNM 530c) on 123I and 99mTc defect size and mismatch, providing a new step toward simultaneous dual-isotope acquisition for combined innervation and perfusion assessment.

Feasibility of biventricular volume and function assessment using first-pass gated 15O-water PET

Background

We investigated the feasibility of left ventricular (LV) and right ventricular (RV) volume and function estimation using a first-pass gated ¹⁵O-water PET. This prospective study included 19 patients addressed for myocardial perfusion reserve assessment using ¹⁵O-water PET. PET data were acquired at rest and after regadenoson stress, and gated first-pass images were reconstructed over the time range corresponding to tracer first-pass through the cardiac cavities and post-processed using TomPool software; LV and RV were segmented using a semi-automated 4D immersion algorithm. LV volumes were computed using a count-based model and a fixed threshold at 30% of the maximal activity. RV volumes were computed using a geometrical model and an adjustable threshold that was set so as to fit LV and RV stroke volumes. Ejection curves were fitted using a deformable reference curve model. LV results were compared to those obtained using ^99mTc-sestamibi gated myocardial SPECT in terms of end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF).

Results

There was an excellent concordance between rest and stress PET in terms of EDV and ESV (Lin’s coefficient ~ 0.85–0.90), SV (~ 0.80), and EF (~ 0.75) for both ventricles. Correlation with myocardial SPECT was high for LV EDV (Pearson’s R = 0.89, p < 0.001) and ESV (R = 0.87, p < 0.001) and satisfying for LV SV (R = 0.67, p < 0.001) and EF (R = 0.67, p < 0.001). Minimal LV ESV overestimation (+ 4 mL, p = 0.03) and EF underestimation (− 4%, p = 0.01) were observed using PET.

Conclusions

Biventricular volume and function assessment are achievable using the first-pass PET, and LV parameters correlate well with those derived from gated myocardial SPECT.