In-vitro and in-vivo imaging of coronary artery stents with Heartbeat OCT.

To quantify the impact of cardiac motion on stent length measurements with Optical Coherence Tomography (OCT) and to demonstrate in vivo OCT imaging of implanted stents, without motion artefacts. The study consists of: clinical data evaluation, simulations and in vivo tests. A comparison between OCT-measured and nominal stent lengths in 101 clinically acquired pullbacks was carried out, followed by a simulation of the effect of cardiac motion on stent length measurements, experimentally and computationally. Both a commercial system and a custom OCT, capable of completing a pullback between two consecutive ventricular contractions, were employed. A 13 mm long stent was implanted in the left anterior descending branch of two atherosclerotic swine and imaged with both OCT systems. The analysis of the clinical OCT images yielded an average difference of 1.1 ± 1.6 mm, with a maximum difference of 7.8 mm and the simulations replicated the statistics observed in clinical data. Imaging with the custom OCT, yielded an RMS error of 0.14 mm at 60 BPM with the start of the acquisition synchronized to the cardiac cycle. In vivo imaging with conventional OCT yielded a deviation of 1.2 mm, relative to the length measured on ex-vivo micro-CT, while the length measured in the pullback acquired by the custom OCT differed by 0.20 mm. We demonstrated motion artefact-free OCT-imaging of implanted stents, using ECG triggering and a rapid pullback.

[Treating cervico-urethral obstructions with laser diode: initial clinical experience]. / Il trattamento dell'ostruzione cervico-uretrale con laser a diodi: esperienza clinica iniziale.

BACKGROUND: The first laser employment for the treatment of the cervico-urethral obstructions (CUO) dates back to the early '90s. This study begins with the analysis of laser basics in Medicine and has the purpose to weigh pros and cons (and limits as well) of laser use in CUO due to Benign Prostatic Hyperplasia (BPH). That is an ageing man's typical disease and there is a huge need of minimally invasive treatments, because people affected by this kind of illness suffer very often from comorbidities, and that could make traditional surgery quite risky. AIM OF THE STUDY: The target of this study is the in vivo experimentation of a brand new laser diode, crated to be specifically used in BPH, and to verify its efficacy and safety. MATERIALS AND METHODS: The subject of the study is the whole laser diode supply, with its double-band laser source (980 nm + 1470 nm), which gains a 140 W-power and is equipped with Water-Free optical fibers of different kinds of tip. We have tested a conical tip fiber on a standard 24-26 F-resectoscope instead of a standard diathermic loop. The conic fiber optimizes the energy on the treated tissue. We recruited 14 patients with CUO caused by BPH, 56 to 70 years old, with a prostatic volume between 33 and 53 cc, and we treated them with laser surgery using the power of 100-110 W. We considered the operative time, the intra-surgery complications and the specific side effects such as hematuria, pain, catheter removal time and the presence or not of acute urinary retention, in order to evaluate the efficacy and safety of this new technique. RESULTS: The possibility of using the same resectoscope as the one used in transurethral resection of prostate (TURP) made everything more comfortable and easy because of the immediate feeling with the new instrument and the actual time of Light Vaporization between 30 and 40 minutes, which is more or less the same time of a standard TURP procedure. CONCLUSIONS: The idea of a double-band-emitting laser used with conical tip fibers appears to be a great solution in the BPH treatment: it uses the principle of low power density plasma in order to treat bigger prostatic tissue areas but never going in depth. In our clinical results, the efficacy of the double-band-emitting laser source (1470 nm + 980 nm) appears to be similar, but even potentially greater, to the actual surgical laser options (such as HoLEP with Ho:YAG laser and PVP with KTP laser), and it is also similar to traditional TURP.