Assessment of myocardial partition coefficient of gadolinium (λ) in dilated cardiomyopathy and its impact on segmental and global systolic function.

PURPOSE: 1) To assess the myocardial partition coefficient (λ) of gadolinium quantified using T1 mapping in dilated cardiomyopathy (DCM); and 2) to assess the impact of increased λ on left ventricular (LV) circumferential strain and ejection fraction in DCM. MATERIALS AND METHODS: Seventeen patients with DCM and 11 controls were prospectively included. All patients and controls underwent a 1.5 T MRI using: 1) cine to quantify LV volumes and function; 2) tagging to quantify circumferential strain in mid-LV; 3) T1 mapping before and 9 minutes after contrast injection to quantify R1, ΔR1, and λ; and 4) inversion recovery 3D Flash was used to assess late gadolinium enhancement (LGE) 10 minutes after Gd DOTA injection (0.2 mmol/kg). We used Student's t-test to compare means, Pearson's test for correlation assessment, and a mixed linear model to integrate the dependency between myocardial segments. RESULTS: No difference in median λ was measured between patients with (0.52 [interquartile range = 0.48-0.56]) and without enhancement on LGE (0.51 [0.47-0.54]; P = 0.07). Circumferential strain value measured in each segment was correlated with the λ measured in the corresponding segment (r = 0.55; P < 0.0001). Multivariate analysis revealed a significant link between the λ in each segment and circumferential strain (0.002 ± 0.001; P = 0.009) and also with ejection fraction (-0.001 ± 0.0008; P = 0.04). CONCLUSION: In DCM, λ correlates independently with circumferential strain and ejection fraction, suggesting that there is a link between λ and systolic function.

Severe symptomatic stenosis of visceral and renal arteries leading primary antiphospholipid syndrome diagnosis.

Antiphospholipid syndrome (APS) is an autoimmune disorder with combination of at least 1 clinical and 1 laboratory criterion as defined by the SAPPORO statement. Clinical criteria result from vascular thrombosis that can affect artery, venous, or small vessel in any tissue or organ. Arterial stenosis is a rare lesion involved in APS, affecting mainly renal or intracranial arteries. We reported a case of a 33-year-old woman with abdominal angina and high blood pressure (BP). Imaging showed tight, not calcified, and hypodense stenosis of mesenteric superior artery and left renal artery, and a thrombosis of the celiac trunk. Treatment was digestive rest followed by angioplasty and stenting of mesenteric and renal artery, anticoagulation, antiplatelet, and statin therapy. Normal BP and digestive function were obtained postoperatively. Biological tests showed a positive lupus anticoagulant at diagnosis and at 12 weeks, which allowed us to make the diagnosis of APS. Physiopathology of stenosis in APS remains unclear but suggests arterial wall partial thrombosis, accelerated atherosclerosis, and/or proliferation of smooth muscle cells. We recommend screening of arterial stenosis in patients with APS and arterial symptoms, and inversely, searching for APS in young patients with atypical arterial stenosis to allow optimal therapy.

Gender differences in response to cold pressor test assessed with velocity-encoded cardiovascular magnetic resonance of the coronary sinus.

BACKGROUND: Gender-specific differences in cardiovascular risk are well known, and current evidence supports an existing role of endothelium in these differences. The purpose of this study was to assess non invasively coronary endothelial function in male and female young volunteers by myocardial blood flow (MBF) measurement using coronary sinus (CS) flow quantification by velocity encoded cine cardiovascular magnetic resonance (CMR) at rest and during cold pressor test (CPT). METHODS: Twenty-four healthy volunteers (12 men, 12 women) underwent CMR in a 3 Tesla MR imager. Coronary sinus flow was measured at rest and during CPT using non breath-hold velocity encoded phase contrast cine-CMR. Myocardial function and morphology were acquired using a cine steady-state free precession sequence. RESULTS: At baseline, mean MBF was 0.63 ± 0.23 mL·g⁻¹·min⁻¹ in men and 0.79 ± 0.21 mL·g⁻¹·min⁻¹ in women. During CPT, the rate pressure product in men significantly increased by 49 ± 36% (p < 0.0001) and in women by 52 ± 22% (p < 0.0001). MBF increased significantly in both men and women by 0.22 ± 0.19 mL·g⁻¹·min⁻¹ (p = 0.0022) and by 0.73 ± 0.43 mL·g⁻¹·min⁻¹ (p = 0.0001), respectively. The increase in MBF was significantly higher in women than in men (p = 0.0012). CONCLUSION: CMR coronary sinus flow quantification for measuring myocardial blood flow revealed a higher response of MBF to CPT in women than in men. This finding may reflect gender differences in endothelial-dependent vasodilatation in these young subjects. This non invasive rest/stress protocol may become helpful to study endothelial function in normal physiology and in physiopathology.

Study of metastatic kinetics in metastatic melanoma treated with B-RAF inhibitors: Introducing mathematical modelling of kinetics into the therapeutic decision.

BACKGROUND: Evolution of metastatic melanoma (MM) under B-RAF inhibitors (BRAFi) is unpredictable, but anticipation is crucial for therapeutic decision. Kinetics changes in metastatic growth are driven by molecular and immune events, and thus we hypothesized that they convey relevant information for decision making. PATIENTS AND METHODS: We used a retrospective cohort of 37 MM patients treated by BRAFi only with at least 2 close CT-scans available before BRAFi, as a model to study kinetics of metastatic growth before, under and after BRAFi. All metastases (mets) were individually measured at each CT-scan. From these measurements, different measures of growth kinetics of each met and total tumor volume were computed at different time points. A historical cohort permitted to build a reference model for the expected spontaneous disease kinetics without BRAFi. All variables were included in Cox and multistate regression models for survival, to select best candidates for predicting overall survival. RESULTS: Before starting BRAFi, fast kinetics and moreover a wide range of kinetics (fast and slow growing mets in a same patient) were pejorative markers. At the first assessment after BRAFi introduction, high heterogeneity of kinetics predicted short survival, and added independent information over RECIST progression in multivariate analysis. Metastatic growth rates after BRAFi discontinuation was usually not faster than before BRAFi introduction, but they were often more heterogeneous than before. CONCLUSIONS: Monitoring kinetics of different mets before and under BRAFi by repeated CT-scan provides information for predictive mathematical modelling. Disease kinetics deserves more interest.

Cardiac multidetector computed tomography in infective endocarditis: a pictorial essay.

OBJECTIVES: The goals of this pictorial essay are: (1) to set out a multislice computed tomography (MSCT) imaging protocol to assess infective endocarditis (IE); (2) to give an MSCT overview of valvular and peri-valvular involvement during IE; (3) to give a CT overview of septic embolism and infectious pseudoaneurysms during IE. METHODS: MSCT acquisition protocols to assess IE are performed in two different phases: the first acquisition, under electrocardiography (ECG) gating, covers the cardiac structures during first-pass iodine injection; the second acquisition covers the thorax, abdomen, pelvic and cerebral regions. RESULTS: Valvular and peri-valvular lesions during IE are: vegetation-a hypodense, homogeneous, irregular mass on a valve or endocardial structure; perforation-a defect in the leaflet; valvular aneurysm-loss of the homogenous curvature of the leaflet; valvular thickening; peri-valvular abscess; pseudoaneurysm; fistula and disinsertion of a prosthetic valve. Extra-cardiac location could involve all organs. CONCLUSIONS: MSCT can be considered as a useful complement in visualising the cardiac lesions of IE if echocardiography is inconclusive. MSCT is the only imaging modality that provides assessment of valvular and peri-valvular involvement, extra-cardiac lesions, and non-invasive evaluation of the coronary artery anatomy, simultaneously. MAIN MESSAGES: • MSCT provides assessment of coronary anatomy, cardiac and extra-cardiac lesions. • MSCT represents an alternative to echocardiography during IE. • Surgical valve replacement is usually required if vegetation is >10 mm. • Peri-valvular extension (abscesses, pseudoaneurysm and fistulae) required surgical treatment.

Epicardial fat volume is associated with coronary microvascular response in healthy subjects: a pilot study.

Epicardial fat (EF) is an active ectopic fat depot, which has been associated with coronary atherosclerosis, and which could early influence endothelial function. We thus investigated the relationship between EF and endothelium-dependent vasoreactivity of the coronary microcirculation, in highly selected healthy volunteers. Myocardial blood flow (MBF) was determined by measuring coronary sinus flow with velocity-encoded cine magnetic resonance imaging (MRI) at 3T. We measured MBF at baseline and in response to sympathetic stimulation by cold pressor testing (CPT) in 30 healthy volunteers with normal left ventricular (LV) function (age 22 ± 4 years, BMI = 21.3 ± 2.8 kg/m(2)). EF volume was volumetrically assessed by manual delineation on short-axis views. CPT was applied by immersing one foot in ice water for 4 min. Mean EF volume was 56 ± 26 ml and mean LV mass 100 ± 28 g. CPT significantly increased heart rate (HR) by 32 ± 19%, systolic blood pressure by 14 ± 10%, and rate-pressure product by 45 ± 25%, P < 0.0001. The increase in HR, reflecting sympathetic stimulation, was not influenced by sex, age or EF volume. CPT induced a decrease in coronary vascular resistance (135 ± 72 vs. 100 ± 42 mm Hg.ml(-1).min.g, P = 0.0006), and a significant increase in MBF (0.81 ± 0.37 vs. 1.24 ± 0.56 ml.min(-1).g(-1), P < 0.0001). Interestingly, we found a significant negative correlation between EF volume and ΔMBF (r= - 0.40, P = 0.03), which remained significant after adjusting for ΔHR. ΔMBF was also associated with adiponectin (r = 0.41, P = 0.046), but not with waist circumference, BMI, C-reactive protein, lipid or glycemic parameters. In multivariate analysis, adiponectin and EF volume remained both independently associated with ΔMBF. A high EF amount is associated with a lower coronary microvascular response, suggesting that EF could early influence endothelial function.

Gadolinium chelate kinetics in cardiac MR imaging of myocarditis: comparison to acute myocardial infarction and impact on late gadolinium enhancement.

OBJECTIVES: To compare the kinetics of gadolinium in myocarditis and myocardial infarction and to establish the best interval between contrast injection and late gadolinium-enhanced (LGE) image acquisition for the diagnosis of acute myocarditis. METHODS: Seventeen patients with acute myocarditis and 12 with acute myocardial infarction underwent Look-Locker sequences before and after administration of 0.2 mmol/kg gadolinium chelate for a period of 14 minutes. The apparent longitudinal relaxation rates (R'1) were calculated from left ventricular blood, enhanced and normal myocardium. LGE cardiac magnetic resonance images were acquired at 5, 10, and 15 minutes after contrast injection. The contrast between enhanced and normal myocardium (Contrastenhaced-normal) was measured, and the quality of the images was analyzed. RESULTS: A faster decline in the R'1 values measured in the areas of myocardial enhancement was recorded in myocarditis than that in myocardial infarction. In myocarditis, the Contrastenhaced-normal values decreased over time (from 60.7 ± 35.1 at 5 minutes vs. 42.1 ± 26.7 at 15 minutes; P = 0.001). However, in myocardial infarction, the Contrastenhaced-normal value remained stable in time (60.7 ± 22.9 at 5 minutes vs. 68.8 ± 16.6 at 15 minutes; P = ns). CONCLUSION: The gadolinium kinetics of acute myocarditis are different from those of acute myocardial infarction. In myocarditis, LGE images acquired 5 minutes after contrast injection provide higher Contrastenhaced-normal and better image quality compared with images taken at later points.