ABSTRACT
Background: Synovitis of the shoulder causes pain; however, it is difficult to accurately determine the area and degree of synovitis from preoperative images. This study investigated the correlation between intraoperative arthroscopic findings and preoperative power Doppler ultrasonography (PDUS) findings for synovitis evaluation. Methods: Forty patients (mean age = 62.0 years; 24 men and 16 women) underwent arthroscopic surgery for partial rotator cuff tears. Three observation areas were evaluated: rotator interval (RI), subacromial bursa, and bicipital groove. The Doppler flow areas and PDUS grade were measured one day before surgery. Arthroscopic findings were visualized intraoperatively and classified into 3 groups: pale, pink, and red. The correlation between the arthroscopic classification and PDUS findings was analyzed. Results: The correlation between intraoperative arthroscopic classification and preoperative PDUS findings, Doppler flow area and PDUS grade, was high for the RI (r = 0.82, 0.70). There was no correlation for the subacromial bursa (r = 0.01, -0.02) and the bicipital groove (r = -0.03, 0.3). Conclusion: Hypervascularity findings in the PDUS were highly correlated with arthroscopic color classification in the RI. Therefore, visualization of hypervascularity in the RI area could be a reliable measure for the assessment of glenohumeral synovitis in patients with partial-thickness rotator cuff tear.
ABSTRACT
Under infrared ultrashort pulse laser stimulation, we investigate temperature-dependent second-harmonic generation (SHG) from nitrogen-vacancy (NV)-introduced bulk diamond. The SHG intensity decreases in the temperature range of 20-300°C, due to phase mismatching caused by refractive index modification. We discover that optical phonon scattering outperforms acoustic phonon scattering in NV diamond by fitting the temperature dependence of the SHG intensity using a model based on the bandgap change via the deformation potential interaction. This study presents an efficient and viable way for creating diamond-based nonlinear optical temperature sensing.
ABSTRACT
We investigate the effect of nitrogen-vacancy (NV) centers in single crystal diamond on nonlinear optical effects using 40 fs femtosecond laser pulses. The near-infrared femtosecond pulses allow us to study purely nonlinear optical effects, such as optical Kerr effect (OKE) and two-photon absorption (TPA), related to unique optical transitions by electronic structures with NV centers. It is found that both nonlinear optical effects are enhanced by the introduction of NV centers in the N + dose levels of 2.0×10 11 and 1.0×10 12 N +/cm 2. In particular, our data demonstrate that the OKE signal is strongly enhanced for the heavily implanted type-IIa diamond. We suggest that the strong enhancement of the OKE is possibly originated from cascading OKE, where the high-density NV centers effectively break the inversion symmetry near the surface region of diamond.
