Objectives　To assess the preliminary clinical results of implantation of dual chamber pacemaker defibrillator and to evaluate the safety and effectiveness of placement of endocardial leads in the axillary vein. Methods　Seven patients with ventricular tachycardia and/or ventricular fibrillation (VT/VF), associated with bradyarrhythmia received implantation of a dual chamber pacemaker defibrillator, including 5 patients with coronary artery disease and 2 patients with dilated cardiomyopathy.The atrial and ventricular leads were introduced via the axillary vein under venographic guidance. Results　Dual chamber pacemaker defibrillators were successfully implanted in the left chest subcutaneous pocket in 5 patients and the left pectoral muscular pocket in 2 patients. All the VT/VF occurring either inducibly during the procedure or spontanuously during follow-up were detected promptly and treated successfully. Both the pacing and sensing functions were satisfactory. The endocardial leads required were successfully introduced via the axillary vein without major complications. Conclusion　Dual chamber pacemaker defibrillators can provide reliable therapy for VT/VF and the dual chamber pacing function. Placement of endocardial leads via the axillary vein under venographic guidance is safe and effective.

Shear wave elastography (SWE) is an emerging technology that provides information about the inherent elasticity of tissues by producing an acoustic radiofrequency force impulse, sometimes called an “acoustic wind,” which generates transversely-oriented shear waves that propagate through the surrounding tissue and provide biomechanical information about tissue quality. Although SWE has the potential to revolutionize bone and joint imaging, its clinical application has been hindered by technical and artifactual challenges. Many of the stumbling blocks encountered during musculoskeletal SWE imaging are readily recognizable and can be overcome, but progressive advances in technology and a better understanding of image acquisition are required before SWE can reliably be used in musculoskeletal imaging.
Acoustics ; Elasticity ; Elasticity Imaging Techniques* ; Joints ; Muscles ; Musculoskeletal System* ; Tendons ; Ultrasonography

Purpose: We evaluated the kinetics of the hypoxia PET radiotracers, [18F]fluoromisonidazole ([18F]FMISO) and [18F] fluoroazomycin-arabinoside ([18F]FAZA), for tumor hypoxia detection and to assess the correlation of hypoxic kinetic parameters with static imaging measures in canine spontaneous tumors. Methods: Sixteen dogs with spontaneous tumors underwent a 150-min dynamic PET scan using either [18F]FMISO or [18F] FAZA. The maximum tumor-to-muscle ratio ­(TMR max ) > 1.4 on the last image frame was used as the standard threshold to determine tumor hypoxia. The tumor time-activity curves were analyzed using irreversible and reversible two-tissue compartment models and graphical methods. T­MR max was compared with radiotracer trapping rate (k 3 ), influx rate (K i ), and distribution volume (V T ). Results: Tumor hypoxia was detected in 7/8 tumors in the [18F]FMISO group and 4/8 tumors in the [18F]FAZA group. All hypoxic tumors were detected at > 120 min with [18F]FMISO and at > 60 min with [18F]FAZA. [18F]FAZA showed better fit with the reversible model. ­TMR max was strongly correlated with the irreversible parameters (k3 and Ki ) for [18F]FMISO at > 90 min and with the reversible parameter (V T ) for [18F]FAZA at > 120 min. Conclusions Our results showed that [18F]FAZA provided a promising alternative radiotracer to [18F]FMISO with detecting the presence of tumor hypoxia at an earlier time (60 min), consistent with its favorable faster kinetics. The strong correlation betwee TMR max over the 90–150 min and 120–150 min timeframes with [18F]FMISO and [18F]FAZA, respectively, with kinetic parameters associated with tumor hypoxia for each radiotracer, suggests that a static scan measurement ( ­TMR max ) is a good alternative to quantify tumor hypoxia.