Performance of compressed sensing for fluorine-19 magnetic resonance imaging at low signal-to-noise ratio conditions.

PURPOSE: To examine the performance of compressed sensing (CS) in reconstructing low signal-to-noise ratio (SNR) 19 F MR signals that are close to the detection threshold and originate from small signal sources with no a priori known location. METHODS: Regularization strength was adjusted automatically based on noise level. As performance metrics, root-mean-square deviations, true positive rates (TPRs), and false discovery rates were computed. CS and conventional reconstructions were compared at equal measurement time and evaluated in relation to high-SNR reference data. 19 F MR data were generated from a purpose-built phantom and benchmarked against simulations, as well as from the experimental autoimmune encephalomyelitis mouse model. We quantified the signal intensity bias and introduced an intensity calibration for in vivo data using high-SNR ex vivo data. RESULTS: Low-SNR 19 F MR data could be reliably reconstructed. Detection sensitivity was consistently improved and data fidelity was preserved for undersampling and averaging factors of α = 2 or = 3. Higher α led to signal blurring in the mouse model. The improved TPRs at α = 3 were comparable to a 2.5-fold increase in measurement time. Whereas CS resulted in a downward bias of the 19 F MR signal, Fourier reconstructions resulted in an unexpected upward bias of similar magnitude. The calibration corrected signal-intensity deviations for all reconstructions. CONCLUSION: CS is advantageous whenever image features are close to the detection threshold. It is a powerful tool, even for low-SNR data with sparsely distributed 19 F signals, to improve spatial and temporal resolution in 19 F MR applications.

Wideband Self-Grounded Bow-Tie Antenna for Thermal MR.

The objective of this study was the design, implementation, evaluation and application of a compact wideband self-grounded bow-tie (SGBT) radiofrequency (RF) antenna building block that supports anatomical proton (1 H) MRI, fluorine (19 F) MRI, MR thermometry and broadband thermal intervention integrated in a whole-body 7.0 T system. Design considerations and optimizations were conducted with numerical electromagnetic field (EMF) simulations to facilitate a broadband thermal intervention frequency of the RF antenna building block. RF transmission (B1+ ) field efficiency and specific absorption rate (SAR) were obtained in a phantom, and the thigh of human voxel models (Ella, Duke) for 1 H and 19 F MRI at 7.0 T. B1+ efficiency simulations were validated with actual flip-angle imaging measurements. The feasibility of thermal intervention was examined by temperature simulations (f = 300, 400 and 500 MHz) in a phantom. The RF heating intervention (Pin = 100 W, t = 120 seconds) was validated experimentally using the proton resonance shift method and fiberoptic probes for temperature monitoring. The applicability of the SGBT RF antenna building block for in vivo 1 H and 19 F MRI was demonstrated for the thigh and forearm of a healthy volunteer. The SGBT RF antenna building block facilitated 19 F and 1 H MRI at 7.0 T as well as broadband thermal intervention (234-561 MHz). For the thigh of the human voxel models, a B1+ efficiency ≥11.8 µT/√kW was achieved at a depth of 50 mm. Temperature simulations and heating experiments in a phantom demonstrated a temperature increase ΔT >7 K at a depth of 10 mm. The compact SGBT antenna building block provides technology for the design of integrated high-density RF applicators and for the study of the role of temperature in (patho-) physiological processes by adding a thermal intervention dimension to an MRI device (Thermal MR).

Toward 19F magnetic resonance thermometry: spin-lattice and spin-spin-relaxation times and temperature dependence of fluorinated drugs at 9.4 T.

OBJECTIVE: This study examines the influence of the environmental factor temperature on the 19F NMR characteristics of fluorinated compounds in phantom studies and in tissue. MATERIALS AND METHODS: 19F MR mapping and MR spectroscopy techniques were used to characterize the 19F NMR characteristics of perfluoro-crown ether (PFCE), isoflurane, teriflunomide, and flupentixol. T1 and T2 mapping were performed, while temperature in the samples was changed (T = 20-60 °C) and monitored using fiber optic measurements. In tissue, T1 of PFCE nanoparticles was determined at physiological temperatures and compared with the T1-measured at room temperature. RESULTS: Studies on PFCE, isoflurane, teriflunomide, and flupentixol showed a relationship between temperature and their physicochemical characteristics, namely, chemical shift, T1 and T2. T1 of PFCE nanoparticles was higher at physiological body temperatures compared to room temperature. DISCUSSION: The impact of temperature on the 19F NMR parameters of fluorinated compounds demonstrated in this study not only opens a trajectory toward 19F MR-based thermometry, but also indicates the need for adapting MR sequence parameters according to environmental changes such as temperature. This will be an absolute requirement for detecting fluorinated compounds by 19F MR techniques in vivo.

Fluorine-19 MRI at 21.1 T: enhanced spin-lattice relaxation of perfluoro-15-crown-5-ether and sensitivity as demonstrated in ex vivo murine neuroinflammation.

OBJECTIVE: Fluorine MR would benefit greatly from enhancements in signal-to-noise ratio (SNR). This study examines the sensitivity gain of 19F MR that can be practically achieved when moving from 9.4 to 21.1 T. MATERIALS AND METHODS: We studied perfluoro-15-crown-5-ether (PFCE) at both field strengths (B0), as a pure compound, in the form of nanoparticles (NP) as employed to study inflammation in vivo, as well as in inflamed tissue. Brains, lymph nodes (LNs) and spleens were obtained from mice with experimental autoimmune encephalomyelitis (EAE) that had been administered PFCE NPs. All samples were measured at both B0 with 2D-RARE and 2D-FLASH using 19F volume radiofrequency resonators together. T1 and T2 of PFCE were measured at both B0 strengths. RESULTS: Compared to 9.4 T, an SNR gain of > 3 was observed for pure PFCE and > 2 for PFCE NPs at 21.1 T using 2D-FLASH. A dependency of 19F T1 and T2 relaxation on B0 was demonstrated. High spatially resolved 19F MRI of EAE brains and LNs at 21.1 T revealed signals not seen at 9.4 T. DISCUSSION: Enhanced SNR and T1 shortening indicate the potential benefit of in vivo 19F MR at higher B0 to study inflammatory processes with greater detail.

Helicobacter pylori cytotoxin-associated gene A impairs human dendritic cell maturation and function through IL-10-mediated activation of STAT3.

Helicobacter pylori infection induces chronic gastric inflammation that can progress to cancer. In this process, the virulence factor cytotoxin-associated gene A (CagA) plays a central role by directly altering epithelial cell signaling and inducing a strong Th1 immune response, which contributes to carcinogenesis. It is still barely understood how the bacterium evades clearance despite this solid immune response and persists lifelong. Dendritic cells (DCs) play a major role in determining the adaptive immune response toward H. pylori, and high levels of regulatory T cells have been detected infiltrating the gastric mucosa of H. pylori-infected patients, which contribute to bacterial persistence. Although murine studies indicate that H. pylori induces tolerization of DCs and impairs DC maturation, the virulence determinants involved are still controversial. Moreover, the signaling cascades engaged in human DC tolerization upon H. pylori infection remain unknown. In the current study, we analyzed the effect of H. pylori infection on human DC maturation and function, focusing on the virulence factors implicated and signaling pathways involved. Our results reveal that CagA is crucial for DC tolerization by modulating IL-10 secretion and, in turn, STAT3 phosphorylation, favoring a regulatory T cell immune response. Our findings help to unravel the paradox why CagA-positive strains, although eliciting a stronger inflammatory response, have overcome evolutionary pressure and persisted in their human host.

Organometallic nucleosides induce non-classical leukemic cell death that is mitochondrial-ROS dependent and facilitated by TCL1-oncogene burden.

BACKGROUND: Redox stress is a hallmark of the rewired metabolic phenotype of cancer. The underlying dysregulation of reactive oxygen species (ROS) is interconnected with abnormal mitochondrial biogenesis and function. In chronic lymphocytic leukemia (CLL), elevated ROS are implicated in clonal outgrowth and drug resistance. The pro-survival oncogene T-cell leukemia 1 (TCL1) is causally linked to the high threshold towards classical apoptosis in CLL. We investigated how aberrant redox characteristics and bioenergetics of CLL are impacted by TCL1 and if this is therapeutically exploitable. METHODS: Bio-organometallic chemistry provided compounds containing a cytosine nucleobase, a metal core (ferrocene, ruthenocene, Fe(CO)3), and a 5'-CH2O-TDS substituent. Four of these metal-containing nucleoside analogues (MCNA) were tested for their efficacy and mode of action in CLL patient samples, gene-targeted cell lines, and murine TCL1-transgenic splenocytes. RESULTS: The MCNA showed a marked and selective cytotoxicity towards CLL cells. MCNA activity was equally observed in high-risk disease groups, including those of del11q/del17p cytogenetics and of clinical fludarabine resistance. They overcame protective stromal cell interactions. MCNA-evoked PARP-mediated cell death was non-autophagic and non-necrotic as well as caspase- and P53-independent. This unconventional apoptosis involved early increases of ROS, which proved indispensible based on mitigation of MCNA-triggered death by various scavengers. MCNA exposure reduced mitochondrial respiration (oxygen consumption rate; OCR) and induced a rapid membrane depolarization (∆ΨM). These characteristics distinguished the MCNA from the alkylator bendamustine and from fludarabine. Higher cellular ROS and increased MCNA sensitivity were linked to TCL1 expression. The presence of TCL1 promoted a mitochondrial release of in part caspase-independent apoptotic factors (AIF, Smac, Cytochrome-c) in response to MCNA. Although basal mitochondrial respiration (OCR) and maximal respiratory capacity were not affected by TCL1 overexpression, it mediated a reduced aerobic glycolysis (lactate production) and a higher fraction of oxygen consumption coupled to ATP-synthesis. CONCLUSIONS: Redox-active substances such as organometallic nucleosides can confer specific cytotoxicity to ROS-stressed cancer cells. Their P53- and caspase-independent induction of non-classical apoptosis implicates that redox-based strategies can overcome resistance to conventional apoptotic triggers. The high TCL1-oncogenic burden of aggressive CLL cells instructs their particular dependence on mitochondrial energetic flux and renders them more susceptible towards agents interfering in mitochondrial homeostasis.

Long-term follow-up after endoscopic stent therapy for benign biliary strictures.

BACKGROUND AND AIMS: Endoscopic therapy holds an important role in the management of benign biliary strictures. This study compares the long-term outcome of stenting therapy depending on the underlying cause of the stricture. METHODS: In a retrospective cohort study, 228 patients with benign biliary strictures were identified using an endoscopic database, hospital charts, and cholangiograms between January 1992 and December 2008. Long-term follow-up was evaluated with cholangiograms, transabdominal ultrasound, laboratory parameters, and physical examination. The median follow-up period was 44.7 months. RESULTS: Endoscopic management showed best long-term results in patients with stone-associated biliary stricture. In this subgroup, endoscopic therapy could be successfully completed in 92% (71/77) of the patients. Patients with postoperative biliary stricture had good outcome in 83% (53/64) of cases. Idiopathic strictures presented a successful outcome in 58% (15/26). Biliary strictures caused by chronic pancreatitis had a significantly poorer outcome compared with strictures of other origin. Therapeutic success of endoscopic therapy could only be observed in 31% of patients (19/61). CONCLUSIONS: Long-term outcome of endoscopic therapy for benign strictures was significantly dependent on the underlying cause of the stricture. In particular, patients with biliary strictures due to chronic pancreatitis benefit least from endoscopic therapy, whereas patients with stone-associated strictures had the highest therapeutic success rate.

Echocardiographic particle image velocimetry for the evaluation of diastolic function in hypertrophic nonobstructive cardiomyopathy.

AIMS: To use particle image velocimetry (PIV) echocardiography for the evaluation of diastolic dysfunction (DD) in patients with hypertrophic nonobstructive cardiomyopathy (HNCM). METHODS: This study included 50 individuals, thereof 30 patients with DD due to HNCM and 20 healthy individuals who served as controls. HNCM patients were divided into 3 groups according to DD severity. All subjects underwent clinical assessment, exercise testing, and standard as well as PIV echocardiography. RESULTS: Energy dissipation was higher in DD patients than in the control group. The severity of flow pattern disturbance corresponded to the degree of DD. In a subgroup of 20 HNCM patients we found significant correlations between invasive measured left ventricular end-diastolic pressure and noninvasive PIV parameters for intraventricular pressure differences and filling. Inter-observer variability (mean difference ± 1.96 SD) for all tested PIV measurements was good. CONCLUSION: According to DD severity, patients with HNCM have disturbed intraventricular flow and reduced intraventricular pressure differences, consistent with a reduced intraventricular suction. PIV echocardiography appears to be feasible for detailed analysis of ventricular vortex flow in DD conditions. Further research using PIV echocardiography in different cardiac pathologies seems warranted.

Evaluation of left ventricular torsion in children with hypertrophic cardiomyopathy.

AIMS: To evaluate the role of torsion in hypertrophic cardiomyopathy in children. METHODS: A total of 88 children with idiopathic hypertrophic cardiomyopathy (n = 24) and concentric hypertrophy (n = 20) were investigated with speckle-tracking echocardiography and compared with age- and gender-matched healthy controls (n = 44). RESULTS: In hypertrophic cardiomyopathy, we found increased torsion (2.8 ± 1.6 versus 1.9 ± 1.0°/cm [controls], p < 0.05) because of an increase in clockwise basal rotation (-8.7 ± 4.3° versus -4.9 ± 2.5° [controls], p < 0.001) and prolonged time to peak diastolic untwisting (3.7 ± 2.4% versus 1.7 ± 0.6% [controls] of cardiac cycle, p < 0.01), but no differences in peak untwisting velocities. Hypertrophic cardiomyopathy patients demonstrated a negative correlation between left ventricular muscle mass and torsion (r = -0.7, p < 0.001). In concentric hypertrophy, torsion was elevated because of increased apical rotation (15.1 ± 6.4° versus 10.5 ± 5.5° [controls], p < 0.05) without correlation with muscle mass. Peak untwisting velocities (- 202 ± 88 versus -145 ± 67°/s [controls], p < 0.05) were higher in concentric hypertrophy and time to peak diastolic untwisting was delayed (1.8 ± 0.8% versus 1.2 ± 0.6% [controls], p < 0.05). CONCLUSIONS: In contrast to an increased counterclockwise apical rotation in concentric hypertrophy, hypertrophic cardiomyopathy is characterised by predominantly enhanced systolic basal clockwise rotation. Diastolic untwisting is delayed in both groups. Torsion may be an interesting marker to guide patients with hypertrophic cardiomyopathy.

Left ventricular rotation and right-left ventricular interaction in congenital heart disease: the acute effects of interventional closure of patent arterial ducts and atrial septal defects.

BACKGROUND: Left ventricular rotation is physiologically affected by acute changes in preload. We investigated the acute effect of preload changes in chronically underloaded and overloaded left ventricles in children with shunt lesions. METHODS: A total of 15 patients with atrial septal defects (Group A: 7.4 ± 4.7 years, 11 females) and 14 patients with patent arterial ducts (Group B: 2.7 ± 3.1 years, 10 females) were investigated using 2D speckle-tracking echocardiography before and after interventional catheterisation. The rotational parameters of the patient group were compared with those of 29 matched healthy children (Group C). RESULTS: Maximal torsion (A: 2.45 ± 0.9°/cm versus C: 1.8 ± 0.8°/cm, p < 0.05), apical peak systolic rotation (A: 12.6 ± 5.7° versus C: 8.7 ± 3.5°, p < 0.05), and the peak diastolic torsion rate (A: -147 ± 48°/second versus C: -110 ± 31°/second, p < 0.05) were elevated in Group A and dropped immediately to normal values after intervention (maximal torsion 1.5 ± 1.1°/cm, p < 0.05, apical peak systolic rotation 7.2 ± 4.1°, p < 0.05, and peak diastolic torsion rate -106 ± 35°/second, p < 0.05). Patients in Group B had decreased maximal torsion (B: 1.8 ± 1.1°/cm versus C: 3.8 ± 1.4°/cm, p < 0.05) and apical peak systolic rotation (B: 8.3 ± 6.1° versus C: 13.9 ± 4.3°, p < 0.05). Defect closure was followed by an increase in maximal torsion (B: 2.7 ± 1.4°/cm, p < 0.05) and the peak diastolic torsion rate (B: -133 ± 66°/second versus -176 ± 84°/second, p < 0.05). CONCLUSIONS: Patients with chronically underloaded left ventricles compensate with an enhanced apical peak systolic rotation, maximal torsion, and quicker diastolic untwisting to facilitate diastolic filling. In patients with left ventricular dilatation by volume overload, the peak systolic apical rotation and the maximal torsion are decreased. After normalisation of the preload, they immediately return to normal and diastolic untwisting rebounds. These mechanisms are important for understanding the remodelling processes.

Timely cholecystectomy: important factors to improve guideline adherence and patient treatment.

OBJECTIVE: Cholecystectomy is one of the most frequently performed surgeries in Germany and is performed as a treatment of acute cholecystitis (guideline S3 IIIB.8) and after endoscopic retrograde cholangiopancreatography for choledocholithiasis with simultaneous cholecystolithiasis (guideline S3 IIIC.6). This article examines the effects of a guideline update from 2017, which recommends prompt cholecystectomy within 24 hours of admission due to cholecystitis or within 72 hours after bile duct repair. In addition, it aims to identify reasons (eg, financial disincentives) and potential for improvement for non-adherence to the guidelines. DESIGN: Methodologically, a retrospective analysis based on routine billing data from 84 Helios Group hospitals from 2016 and 2022, with a total of 45 393 included cases, was applied. The guideline adherence rate is used as the main outcome measure. RESULTS: Results show the guideline updates led to a statistically significant increase in the proportion of cholecystectomy performed in a timely manner (guideline S3 IIIB.8: increase from 43% to 49%, p<0.001; guideline S3 IIIC.6: increase from 7% to 20%, p<0.001). Medical, structural and financial reasons for non-adherence could be identified. CONCLUSION: As possible reasons for non-adherence, medical factors such as advanced age, multimorbidity and frailty could be identified. Analyses of structural factors revealed that hospitals in very rural regions are less likely to perform timely cholecystectomies, presumably due to infrastructural and personnel-capacity bottlenecks. A similar picture emerges for maximum-care hospitals, which might be explained by more severe and complex cases on average. Further evaluation indicates that an increase in and better hospital-internal participation of gastroenterologists in remuneration could lead to even greater adherence to the S3 IIIC.6 guideline.

Treatment of Cheyne-Stokes respiration reduces arrhythmic events in chronic heart failure.

OBJECTIVE: This study aimed to investigate whether adequate treatment of Cheyne-Stokes respiration (CSR) reduces the risk of arrhythmic events in patients with chronic heart failure (CHF). METHODS: A cohort of 403 registry patients with CHF (LVEF≤45%, NYHA-class≥2) and implanted cardioverter-defibrillator devices (ICD) was studied. They underwent overnight polygraphy, with 221 having mild or no CSR (apnea-hypopnea index [AHI]<15/h), and 182 having moderate to severe CSR (AHI>15/h). Latter ones were offered therapy with adaptive servoventilation (ASV), which 96 patients accepted and 86 rejected. During follow-up (21± 15 months) defibrillator therapies were recorded in addition to clinical and physiologic measures of heart failure severity. RESULTS: Event-free survival from (a) appropriate cardioverter-defibrillator therapies and (b) appropriately monitored ventricular arrhythmias was shorter in the untreated CSR group compared to the treated CSR and the no CSR group. Stepwise Cox proportional hazard regression analysis showed untreated CSR (a: hazard ratio [HR] 1.99, 95% confidence interval [CI] 1.46-2.72, P < 0.001; b: HR 2.19, 95%CI 1.42-3.37, P < 0.001), but not treated CSR (a: HR 1.06, 95%CI 0.74-1.50; P = 0.77; b: HR 1.21, 95%CI 0.75-1.93, P = 0.43) was an independent risk factor. The treated CSR group showed improvements in cardiac function and respiratory stability compared to the untreated CSR group. CONCLUSION: This study demonstrates a decrease of appropriate defibrillator therapies by ASV treated CSR in patients with CHF and ICD. A reduced exposure to hyperventilation, hypoxia, and improvement in indices of CHF severity and neurohumoral disarrangements are potential causative mechanisms.

Left ventricular dyssynchrony predicts clinical response to CRT - a long-term follow-up single-center prospective observational cohort study.

BACKGROUND: Until now, there is no consensus regarding the definition of a clinical response to cardiac resynchronization therapy (CRT) in patients with chronic heart failure (CHF) and systolic left ventricular (LV) dysfunction. The aim of this study was to evaluate if echocardiography is predictive for an objective improvement in exercise capacity during long-term follow-up of CRT. METHODS: Each patient underwent echocardiography and spiroergometry both at baseline and at last follow-up. Left ventricular dyssynchrony (LVD) before CRT was defined by tissue Doppler imaging (TDI) as intra-LV delay ≥40 msec (septal-lateral or anterior-posterior). Clinical response to CRT was defined as increase of peakVO2 or as increase of maximal workload >10% as compared to baseline. RESULTS: Mean follow-up was 69 ± 37 months. From the 238 consecutive patients included in the study, 141 (59%) were classified as clinical responders and 97 (41%) as nonresponders. Baseline data of responders and nonresponders were comparable. However, clinical responders showed more often LVD (64%) than nonresponders (42%, P = 0.004). On multivariate regression analysis, nonischemic origin of CHF (ß-coefficient in the final model 0.1, P = 0.04) and LVD at baseline (ß-coefficient in the final model 0.2, P < 0.001) were independently associated with clinical response during long-term follow-up. Patients with LVD at baseline had significant more often an improvement of left ventricular ejection fraction >10% (P = 0.02) and a reduction of left ventricular end-diastolic diameter (LVEDD) >10% (P < 0.01) than patients without LVD at baseline. CONCLUSIONS: LVD at baseline as assessed by a straightforward echocardiographic approach predicts the long-term clinical response to CRT and is associated with a more pronounced reverse LV remodeling.

[Robotic-assisted resection of a symptomatic Müllerian duct cyst]. / Roboter-assistierte Resektion einer symptomatischen Müller-Gang-Zyste.

Cysts in the lesser pelvis are a rare disease and most often an incidental finding from routine diagnostic investigation. Published information is controversial. These cysts are distinguished by localisation, content of the cyst and accompanying anatomical anomalies. In this case, we report a 33 years old man who presented to our clinic due to a large retrovesical cyst. Because of lower abdominal pain and problems with defecation, the cyst was diagnosed by ultrasound. Further radiological diagnostic testing confirmed the presence of a retrovesical cyst of unknown malignancy, which was retrospectively evaluated as a Müllerian duct cyst. Due to symptoms and potential malignancy of the cyst, the decision was made to perform surgery. With the help of the operation robot, this benign cyst was safely and completely removed. In a follow-up, the patient presented free of symptoms and sonographically there was no sign of recurrence. Therefore robotic-assisted resection is a safe procedure to treat large symptomatic Müllerian duct cysts.

First in vivo fluorine-19 magnetic resonance imaging of the multiple sclerosis drug siponimod.

Theranostic imaging methods could greatly enhance our understanding of the distribution of CNS-acting drugs in individual patients. Fluorine-19 magnetic resonance imaging (19F MRI) offers the opportunity to localize and quantify fluorinated drugs non-invasively, without modifications and without the application of ionizing or other harmful radiation. Here we investigated siponimod, a sphingosine 1-phosphate (S1P) receptor antagonist indicated for secondary progressive multiple sclerosis (SPMS), to determine the feasibility of in vivo 19F MR imaging of a disease modifying drug. Methods: The 19F MR properties of siponimod were characterized using spectroscopic techniques. Four MRI methods were investigated to determine which was the most sensitive for 19F MR imaging of siponimod under biological conditions. We subsequently administered siponimod orally to 6 mice and acquired 19F MR spectra and images in vivo directly after administration, and in ex vivo tissues. Results: The 19F transverse relaxation time of siponimod was 381 ms when dissolved in dimethyl sulfoxide, and substantially reduced to 5 ms when combined with serum, and to 20 ms in ex vivo liver tissue. Ultrashort echo time (UTE) imaging was determined to be the most sensitive MRI technique for imaging siponimod in a biological context and was used to map the drug in vivo in the stomach and liver. Ex vivo images in the liver and brain showed an inhomogeneous distribution of siponimod in both organs. In the brain, siponimod accumulated predominantly in the cerebrum but not the cerebellum. No secondary 19F signals were detected from metabolites. From a translational perspective, we found that acquisitions done on a 3.0 T clinical MR scanner were 2.75 times more sensitive than acquisitions performed on a preclinical 9.4 T MR setup when taking changes in brain size across species into consideration and using equivalent relative spatial resolution. Conclusion: Siponimod can be imaged non-invasively using 19F UTE MRI in the form administered to MS patients, without modification. This study lays the groundwork for more extensive preclinical and clinical investigations. With the necessary technical development, 19F MRI has the potential to become a powerful theranostic tool for studying the time-course and distribution of CNS-acting drugs within the brain, especially during pathology.

Predictors of recurrence in patients undergoing cryoballoon ablation for treatment of atrial fibrillation: the independent role of sleep-disordered breathing.

INTRODUCTION: In patients with atrial fibrillation (AF) undergoing pulmonary vein isolation, cryoballoon technique (cryoPVI) has been adopted in many centers. This study aimed to evaluate predictors of AF recurrence including impact of sleep-disordered breathing (SDB). METHODS AND RESULTS: In 82 patients consecutively assigned to cryoPVI cardiorespiratory screening for SDB, assessment of medical history, ECG, echocardiography, standard laboratory measurement, and blood gas analysis were performed prior to intervention. After a 3-month blanking period, a 7-day Holter ECG was performed at 3, 6 and then every 6 months to determine AF recurrence. Seventy-five patients (69 paroxysmal AF, 6 persistent AF, 22 female, age 60 ± 9 years) completed at least 6-month follow-up. Median follow-up of 12 months (interquartile range 6-18 months) confirmed maintenance of sinus rhythm in 69.4% of these patients. Stepwise forward regression model revealed moderate to severe SDB (cut-off apnea-hypopnea-index (AHI) ≥ 15 per hour; Hazard Ratio (HR) 2.95, P = 0.04), early recurrence of AF (HR 8.74, P < 0.001), persistent AF (HR 7.16, P < 0.001), preprocedural class III-antiarrhythmic drug treatment (HR 3.63, P = 0.02), but not SDB per se (AHI ≥ 5 per hour) as independent predictors for AF recurrence. CONCLUSION: Moderate to severe SDB is a treatable condition that independently predicts AF recurrence in patients undergoing cryoPVI. Screening for SDB and adequate treatment may improve long-term success of cryoPVI.

Can echocardiographic particle image velocimetry correctly detect motion patterns as they occur in blood inside heart chambers? A validation study using moving phantoms.

AIMS: To validate Echo Particle Image Velocimetry (PIV) METHODS: High fidelity string and rotating phantoms moving with different speed patterns were imaged with different high-end ultrasound systems at varying insonation angles and frame rates. Images were analyzed for velocity and direction and for complex motion patterns of blood flow with dedicated software. Post-processing was done with MATLAB-based tools (Dflow, JUV, University Leuven). RESULTS: Velocity estimation was accurate up to a velocity of 42 cm/s (r = 0.99, p < 0.001, mean difference 0.4 ± 2 cm/s). Maximally detectable velocity, however, was strongly dependent on frame rate and insonation angle and reached 42 cm/s under optimal conditions. At higher velocities estimates became random. Direction estimates did depend less on velocity and were accurate in 80-90%. In-plane motion patterns were correctly identified with three ultrasound systems. CONCLUSION: Echo-PIV appears feasible. Velocity estimates are accurate, but the maximal detectable velocity depends strongly on acquisition parameters. Direction estimation works sufficiently, even at higher velocities. Echo-PIV appears to be a promising technical approach to investigate flow patterns by echocardiography.

Symptoms of sleep apnoea in chronic heart failure--results from a prospective cohort study in 1,500 patients.

BACKGROUND: In patients with chronic heart failure, sleep-disordered breathing (SDB) is a common co-morbidity worsening prognosis. The aim of this study was to investigate whether assessment of specific symptoms can elucidate presence of SDB in these patients. METHODS: A prospective questionnaire scoring investigation on possible symptoms of sleep apnoea (nocturia, fatigue, daytime sleepiness, snoring, nocturnal sweating, witnessed apnoea's, nap) was conducted in 1,506 consecutive patients with stable chronic heart failure (LVEF ≤45%, NYHA ≥2). Afterwards, polysomnography or polygraphy, capillary blood gas analysis, echocardiography, and cardiopulmonary exercise testing were performed. RESULTS: Adjusted for all significant covariates, snoring (p < 0.01) was the only symptom independently associated with OSA, while witnessed apnoeas (p = 0.02) and fatigue (p = 0.03) independently predicted for CSR. As additional parameters, higher BMI (threshold 26.6; p < 0.01) and higher pCO(2) (threshold 37.6 mmHg; p < 0.01) were independently associated with OSA and male gender (p < 0.001) and lower pCO(2) (threshold 35.0 mmHg; p < 0.001) with CSA. Cumulative questionnaire score results did not sufficiently (OSA--sensitivity 0.40, specificity 0.74; CSA--sensitivity 0.57, specificity 0.59) predict SDB. CONCLUSION: Although in chronic heart failure patients with either OSA or CSA specific symptoms are apparent, combining clinical data, demographic data, and capillary blood gas analysis results appears favourable to determine the presence of SDB.

Myocardial fibrosis is associated with biventricular dysfunction in patients with hypertrophic cardiomyopathy.

AIMS: To assess left (LV) and right ventricular (RV) function by two-dimensional (2D) speckle tracking echocardiography and its relation to myocardial fibrosis in hypertrophic cardiomyopathy (HCM). METHODS: We enrolled 50 HCM patients (30 male; 47.3 ± 9.9 years) in our study. Each patient received echocardiography with modern high-end scanners. For speckle tracking analysis of LV and RV function the dedicated software was used. The presence of myocardial fibrosis was detected by cardiac magnetic resonance imaging (MRI). RESULTS: For intraobserver variability of RV global longitudinal strain, we found a correlation of r = 0.89 (p < 0.001) with a minor bias of 4.9 ± 2.9%. On cardiac MRI 30 patients (60%) demonstrated late gadolinium-enhancement (LGE) of the LV. Of these patients only 7% showed LGE of the RV. HCM patients with myocardial fibrosis had less global longitudinal LV strain in comparison to patients without myocardial fibrosis (-12.8 ± 2.2 vs -21.1 ± 2.6, P < 0.001), thicker interventricular septums (23.7 ± 4.0 vs 19.2 ± 5.1, P < 0.001), larger left atria (34.9 ± 7.1 vs 23.9 ± 5.1, P < 0.001), and impaired diastolic function (E/A-ratio: 1.02 ± 0.22 vs 1.15 ± 0.18, P < 0.01). Comparable results were found for RV function. LV and RV strain correlated with r = 0.85 (p < 0.001). CONCLUSIONS: HCM is not only a disease of the LV. LGE in HCM is associated with both LV and RV dysfunction. Although RV LGE occurs only in a minority of patients with HCM and LV fibrosis, speckle tracking echocardiography is feasible for evaluating LV and RV dysfunction in these patients.

Diagnostic performance of handheld echocardiography for the assessment of basic cardiac morphology and function: a validation study in routine cardiac patients.

AIMS: To investigate the intra- and interrater variability of expert users in the interpretation of handheld echocardiographic studies (HAND). METHODS: We scanned 320 consecutive patients with both HAND and high-end (HIGH) scanners. Images were interpreted independently by two blinded level III echocardiographers. Readings from the HIGH scanner served as the gold standard. Segmental endocardial-border delineation was scored to describe image quality. Assessment of left ventricular (LV) dimensions and regional/global LV function, and grading of valve disease were compared. RESULTS: We obtained correlations of r > 0.8 (P < 0.01) for intrarater variability for both expert readers when they analyzed HAND and HIGH images in relation to image quality, wall-motion abnormalities, and LV measurements. For intrarater variability of LVEF assessment, the correlations were at least moderate (r > 0.6, P < 0.01). Interrater variability for HIGH images was r = 0.9 (P < 0.01) for all parameters. Interrater variability for HAND images was less favorable for all parameters, but was at least moderate (r > 0.6, P < 0.01). All cases of pericardial effusion were detected. The agreement for the detection and grading of mitral and aortic regurgitation was at least moderate (κ > 0.6, P < 0.01). Detection of tricuspid regurgitation was less favorable, but only cases of mild regurgitation were missed. All cases of aortic stenosis were detected by both echocardiographers. CONCLUSIONS: In relation to the basic assessment of cardiac morphology and function, the interpretation by experienced echocardiographers of images obtained using handheld echocardiographic devices showed a moderate to very good correlation with standard echocardiography.