Objective To assess the accuracy of two-dimensional phase contrast (2D-PC) MR method for blood flow measurement within transverse sinusesby comparing this method with cine phase contrast (cine-PC) MR and Doppler in volunteers and patients. Methods (1) A total of 12 transverse sinuses were examined in 8 healthy volunteers. 2D-PC MR and cine-PC MR were used respectively to measure the transverse area of flow, the flow velocities, and the volumetric flow rates in the same position in every transverse sinus. Paired t-test was used for comparison between the results determined by 2D-PC MR and that determined by cine-PC MR. (2) A total of 6 transverse sinuses were examined in 5 patients who needed operation. 2D-PC MR was used to determine the blood flow velocity of transverse sinus before operation, and Doppler was used to determine the blood flow velocity of the same transverse sinus during operation. The linear regression analysis was used for statistical analysis. Results (1) Statistical analysis indicated that there were no significant difference among the transverse area of flow (t=-1.106, P=0.293), the flow velocities (t=0.262, P=0.798), and the volumetric flow rates (t=0.439, P=0.669) measured by using 2D-PC MR and cine PC MR, respectively. (2) The correlation between flow velocities determined by 2D-PC MR imaging before operation and that determined by Doppler during operation was in excellent agreement (=1.303x+0.62,r 2=0.88). Conclusion 2D-PC MR may be a practical convenient method for blood flow measurement within transverse sinuses system.

Objective:To observe the efficacy of dexamethasone intravitreal implant (DEX) combined with pars plana vitrectomy (PPV) in eyes with severe idiopathic epimacular membrane (IMEM).Methods:A prospective clinical case study. From December 2018 to May 2021, 24 patients with 25 eyes of severe IMEM diagnosed in Tianjin Medical University Eye Hospital were included in the study. Among them, 7 males had 7 eyes, 17 females had 18 eyes. Age was 57 to 84 years old. The IMEM stage was 3 to 4 examined by spectral domain optical coherence tomography (SD-OCT). All eyes were performed best corrected visual acuity (BCVA) and central macular thickness (CMT) by SD-OCT. The patients were randomly divided into PPV group (11 eyes) and PPV+DEX group (14 eyes). Standard PPV by three-channel 25G was performed. Phacoemulsification, membrane stripping and intraocular lens implantation were combined during the operation. Patients received vitreous injection of 0.7 mg DEX in PPV+DEX group at the end of the operation. At 1 week, 1 month, 3 months and 6 months after operation, the same equipments and methods were used to perform relevant examinations. The changes of BCVA and CMT were compared between the two groups by t test. Results:Compared with before operation, at 1, 3 and 6 months after operation, the BCVA of the eyes in the PPV+DEX group was significantly improved ( t=3.974, 4.639, 4.453), CMT was significantly decreased ( t=2.955, 3.722, 4.364), the differences were statistically significant ( P<0.05); at 3 and 6 months after surgery, the BCVA of the eyes in the PPV group was significantly improved ( t=2.983, 4.436), CMT was significantly decreased ( t=2.983, 3.461), the differences were statistically significant ( P<0.05). Conclusion:In the treatment of severe IMEM, DEX can accelerate the early postoperative visual recovery and reduce CMT.