Kirsten Bouchelouche

Multimodality imaging-guided left ventricular lead placement in cardiac resynchronization therapy: a randomized controlled trial.

Left ventricular (LV) lead position at the latest mechanically activated non‐scarred myocardial LV region confers improved response to cardiac resynchronization therapy (CRT). We conducted a double‐blind, randomized controlled trial to evaluate the clinical benefit of multimodality imaging‐guided LV lead placement in CRT.

Empiric versus imaging guided left ventricular lead placement in cardiac resynchronization therapy (ImagingCRT): study protocol for a randomized controlled trial.

BackgroundCardiac resynchronization therapy (CRT) is an established treatment in heart failure patients. However, a large proportion of patients remain nonresponsive to this pacing strategy. Left ventricular (LV) lead position is one of the main determinants of response to CRT. This study aims to clarify whether multimodality imaging guided LV lead placement improves clinical outcome after CRT.Methods/DesignThe ImagingCRT study is a prospective, randomized, patient- and assessor-blinded, two-armed trial. The study is designed to investigate the effect of imaging guided left ventricular lead positioning on a clinical composite primary endpoint comprising all-cause mortality, hospitalization for heart failure, or unchanged or worsened functional capacity (no improvement in New York Heart Association class and <10% improvement in six-minute-walk test). Imaging guided LV lead positioning is targeted to the latest activated non-scarred myocardial region by speckle tracking echocardiography, single-photon emission computed tomography, and cardiac computed tomography. Secondary endpoints include changes in LV dimensions, ejection fraction and dyssynchrony. A total of 192 patients are included in the study.DiscussionDespite tremendous advances in knowledge with CRT, the proportion of patients not responding to this treatment has remained stable since the introduction of CRT. ImagingCRT is a prospective, randomized study assessing the clinical and echocardiographic effect of multimodality imaging guided LV lead placement in CRT. The results are expected to make an important contribution in the pursuit of increasing response rate to CRT.Trial registrationClinicaltrials.gov identifier NCT01323686. The trial was registered March 25, 2011 and the first study subject was randomized April 11, 2011.

PET/Computed Tomography in Renal, Bladder, and Testicular Cancer.

Imaging plays an important role in the clinical management of cancer patients. Hybrid imaging with PET/computed tomography (CT) is having a broad impact in oncology, and in recent years PET/CT is beginning to have an impact in urooncology. In both bladder and renal cancers, there is a need to study the efficacy of other tracers than F-18 fluorodeoxyglucose (FDG), particularly tracers with limited renal excretion. Thus, new tracers are being introduced. This review focuses on the clinical role of FDG and other PET agents in renal, bladder, and testicular cancers.

Subcutaneous Lobular Capillary Hemangioma on 68Ga-PSMA PET/CT.

We present a case of a subcutaneous process in the abdominal wall with high prostate-specific membrane antigen (PSMA) activity on Ga-PSMA PET/CT. Histology demonstrated a benign lobular capillary hemangioma with a high vascular density, with highly PSMA-positive endothelial cells. It is well known that PSMA is expressed in different tissue, including neovasculature in various malignant tumors, and the knowledge is rapidly evolving as new discoveries appear.

DaPeCa-3: promising results of sentinel node biopsy combined with 18F-fluorodeoxyglucose positron emission tomography/computed tomography in clinically lymph node-negative patients with penile cancer – a national study from Denmark

To estimate the diagnostic accuracy of sentinel node biopsy (SNB) combined with preoperative 18F‐fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) for inguinal lymph node (LN) evaluation in patients with invasive penile squamous cell carcinoma (PSCC) with no clinical evidence of inguinal metastases (cN0) at two tertiary centres with complete clinical follow‐up.

Prostate-Specific Membrane Antigen PET/CT: Uptake in Lymph Nodes With Active Sarcoidosis.

We describe 2 cases of Ga-PSMA PET/CT in prostate cancer patients. Both cases demonstrated symmetrical bilateral involvement of mediastinal and hilar lymph nodes besides findings in relation with prostatic disease. In both cases, endobronchial ultrasound-guided biopsy showed that the involvement of the thoracic lymph nodes was caused by nonnecrotic granulomas compatible with sarcoidosis. The cases demonstrated that increased Ga-PSMA uptake can be seen in lymph nodes with active sarcoidosis, with images mimicking those well known from FDG PET/CT. Because of these findings, granulomatous disease has to be included in the differential diagnostic evaluation of patients with Ga-PSMA-positive lymph nodes.

Metastases From Colorectal Cancer Avid on 68Ga-PSMA PET/CT

Ga-PSMA PET/CT is currently used for detection of prostate cancer including metastases, even at low prostate-specific antigen values. A grown number of reports have shown increased uptake of PSMA in neovessels of nonprostatic malignancies including lung cancer, and recently a case report has demonstrated increased PSMA uptake in colorectal adenocarcinoma. In this case report, we demonstrate increased Ga-PMSA uptake on PET/CT in metastases from previously treated colon adenocarcinoma, and it illustrates the importance of histology of suspicious lesions on Ga-PSMA PET/CT.

Automatic Extraction of Myocardial Mass and Volume Using Parametric Images from Dynamic Nongated PET

Dynamic cardiac PET is used to quantify molecular processes in vivo. However, measurements of left ventricular (LV) mass and volume require electrocardiogram-gated PET data. The aim of this study was to explore the feasibility of measuring LV geometry using nongated dynamic cardiac PET. Methods: Thirty-five patients with aortic-valve stenosis and 10 healthy controls underwent a 27-min 11C-acetate PET/CT scan and cardiac MRI (CMR). The controls were scanned twice to assess repeatability. Parametric images of uptake rate K1 and the blood pool were generated from nongated dynamic data. Using software-based structure recognition, the LV wall was automatically segmented from K1 images to derive functional assessments of LV mass (mLV) and wall thickness. End-systolic and end-diastolic volumes were calculated using blood pool images and applied to obtain stroke volume and LV ejection fraction (LVEF). PET measurements were compared with CMR. Results: High, linear correlations were found for LV mass (r = 0.95), end-systolic volume (r = 0.93), and end-diastolic volume (r = 0.90), and slightly lower correlations were found for stroke volume (r = 0.74), LVEF (r = 0.81), and thickness (r = 0.78). Bland–Altman analyses showed significant differences for mLV and thickness only and an overestimation for LVEF at lower values. Intra- and interobserver correlations were greater than 0.95 for all PET measurements. PET repeatability accuracy in the controls was comparable to CMR. Conclusion: LV mass and volume are accurately and automatically generated from dynamic 11C-acetate PET without electrocardiogram gating. This method can be incorporated in a standard routine without any additional workload and can, in theory, be extended to other PET tracers.

Automatic extraction of forward stroke volume using dynamic PET/CT: a dual-tracer and dual-scanner validation in patients with heart valve disease

BackgroundThe aim of this study was to develop and validate an automated method for extracting forward stroke volume (FSV) using indicator dilution theory directly from dynamic positron emission tomography (PET) studies for two different tracers and scanners.Methods35 subjects underwent a dynamic 11C-acetate PET scan on a Siemens Biograph TruePoint-64 PET/CT (scanner I). In addition, 10 subjects underwent both dynamic 15O-water PET and 11C-acetate PET scans on a GE Discovery-ST PET/CT (scanner II). The left ventricular (LV)-aortic time-activity curve (TAC) was extracted automatically from PET data using cluster analysis. The first-pass peak was isolated by automatic extrapolation of the downslope of the TAC. FSV was calculated as the injected dose divided by the product of heart rate and the area under the curve of the first-pass peak. Gold standard FSV was measured using phase-contrast cardiovascular magnetic resonance (CMR).ResultsFSVPET correlated highly with FSVCMR (r = 0.87, slope = 0.90 for scanner I, r = 0.87, slope = 1.65, and r = 0.85, slope = 1.69 for scanner II for 15O-water and 11C-acetate, respectively) although a systematic bias was observed for both scanners (p < 0.001 for all). FSV based on 11C-acetate and 15O-water correlated highly (r = 0.99, slope = 1.03) with no significant difference between FSV estimates (p = 0.14).ConclusionsFSV can be obtained automatically using dynamic PET/CT and cluster analysis. Results are almost identical for 11C-acetate and 15O-water. A scanner-dependent bias was observed, and a scanner calibration factor is required for multi-scanner studies. Generalization of the method to other tracers and scanners requires further validation.

Myocardial Oxygen Consumption and Efficiency in Aortic Valve Stenosis Patients With and Without Heart Failure

Background Myocardial oxygen consumption (MVO2) and its coupling to contractile work are fundamentals of cardiac function and may be involved causally in the transition from compensated left ventricular hypertrophy to failure. Nevertheless, these processes have not been studied previously in patients with aortic valve stenosis (AS). Methods and Results Participants underwent 11C‐acetate positron emission tomography, cardiovascular magnetic resonance, and echocardiography to measure MVO2 and myocardial external efficiency (MEE) defined as the ratio of left ventricular stroke work and the energy equivalent of MVO2. We studied 10 healthy controls (group A), 37 asymptomatic AS patients with left ventricular ejection fraction ≥50% (group B), 12 symptomatic AS patients with left ventricular ejection fraction ≥50% (group C), and 9 symptomatic AS patients with left ventricular ejection fraction <50% (group D). MVO2 did not differ among groups A, B, C, and D (0.105±0.02, 0.117±0.024, 0.129±0.032, and 0.104±0.026 mL/min per gram, respectively; P=0.07), whereas MEE was reduced in group D (21.0±1.6%, 22.3±3.3%, 22.1±4.2%, and 17.3±4.7%, respectively; P<0.05). Similarly, patients with global longitudinal strain greater than −12% and paradoxical low‐flow, low‐gradient AS had impaired MEE (P<0.05 versus controls). The ability to discriminate between symptomatic and asymptomatic patients was superior for global longitudinal strain compared with MVO2 and MEE (area under the curve 0.98, 0.48, and 0.61, respectively; P<0.05). Conclusions AS patients display a persistent ability to maintain normal MVO2 and MEE (ie, the ability to convert energy into stroke work); however, patients with left ventricular ejection fraction <50%; global longitudinal strain greater than −12%; or paradoxical low‐flow, low‐gradient AS demonstrate reduced MEE. These findings suggest that mitochondrial uncoupling contributes to the dismal prognosis in patients with reduced contractile function or paradoxical low‐flow, low‐gradient AS.