Nonpalpable implant removals at centre of experience in France: a cohort study.

OBJECTIVE(S): Management and localisation strategies to remove nonpalpable contraceptive implants may be difficult. We aimed to evaluate our imaging modalities to identify deep implant and patient outcomes related to removal. STUDY DESIGN: In this retrospective study, we reviewed all cases referred to our specialised centre for nonpalpable contraceptive implants from January 2018 to August 2022. RESULTS: Out of the cohort studied, 47 female subjects exhibited nonpalpable implants. The implant was nonpalpable for thirty-six patients (76,6%) immediately after the insertion whereas it was not palpable several months after the insertion for eleven patients (23.4%). Twelve patients (25.5%) had one or more failed removal attempts before referral.All 47 implants were successfully visualised via ultrasound in the upper arm: 40 implants (85.1%) were located in the subdermal tissue, 4 (8.5%) were intrafascial and 3 (6.4%) were intramuscular. Depth of the implant was 4.0 mm [1.7 - 12.0]. No clinical factors were statistically associated with differences in depth or location (subdermal vs subfascial). Removal procedures were mainly under local anaesthesia in 74.5% of cases in an outpatient setting. There were two Clavien-Dindo grade 1 complications (one case of cutaneous scar dehiscence and one transient postoperative neuropathic complaint in the upper arm resolved within 3 months under analgetics). CONCLUSIONS: Identification of deep implants requires following the ultrasound modality protocol. Ultrasound detection makes easy and safe implant removal. Training programs for the insertion as well as for the removal of correct and incorrect inserted implants should be continued and developed all around the world.

Surface modification effect on contrast agent efficiency for X-ray based spectral photon-counting scanner/luminescence imaging: from fundamental study to in vivo proof of concept.

X-Ray imaging techniques are among the most widely used modalities in medical imaging and their constant evolution has led to the emergence of new technologies. The new generation of computed tomography (CT) systems - spectral photonic counting CT (SPCCT) and X-ray luminescence optical imaging - are examples of such powerful techniques. With these new technologies the rising demand for new contrast agents has led to extensive research in the field of nanoparticles and the possibility to merge the modalities appears to be highly attractive. In this work, we propose the design of lanthanide-based nanocrystals as a multimodal contrast agent with the two aforementioned technologies, allowing SPCCT and optical imaging at the same time. We present a systematic study on the effect of the Tb3+ doping level and surface modification on the generation of contrast with SPCCT and the luminescence properties of GdF3:Tb3+ nanocrystals (NCs), comparing different surface grafting with organic ligands and coatings with silica to make these NCs bio-compatible. A comparison of the luminescence properties of these NCs with UV revealed that the best results were obtained for the Gd0.9Tb0.1F3 composition. This property was confirmed under X-ray excitation in microCT and with SPCCT. Moreover, we could demonstrate that the intensity of the luminescence and the excited state lifetime are strongly affected by the surface modification. Furthermore, whatever the chemical nature of the ligand, the contrast with SPCCT did not change. Finally, the successful proof of concept of multimodal imaging was performed in vivo with nude mice in the SPCCT taking advantage of the so-called color K-edge imaging method.