Two-step image registration based on control volumes / 南方医科大学学报

<p><b>OBJECTIVE</b>To increase the accuracy of beam targeting and improve the dose distributions in radiotherapy using a robust image registration algorithm based on control volumes.</p><p><b>METHODS</b>Control volume mapping and thin-plate spline deformable transformation were combined. The use of the control volumes increased the accuracy for the deformable registration. A bi-directional mapping method was also employed to correctly match the control volumes.</p><p><b>RESULTS</b>The clinical images were simulated using the proposed two-step image registration algorithm. The simulation results indicated that the registration algorithm was robust and universal, even in cases of obvious deformation.</p><p><b>CONCLUSIONS</b>The algorithm provides a more convenient and robust resolution as compared to manual landmark-based methods and single-step deformable transformations, and may help in automatic image registration in radiation therapy.</p>

A new method for predicting anterior chamber depth in intraocular lens implantation / 南方医科大学学报

<p><b>OBJECTIVE</b>To propose a method for predicting the postoperative anterior chamber depth value (ACD) based on the evaluation standard of contrast sensitivity function (CSF).</p><p><b>METHODS</b>In a personalized eye model, the natural lens was replaced with an artificial lens, and the tracing method based on ZEMAX software was utilized to simulate the pseudophakic optical system. The best MTF curve was obtained through optical optimization to calculate the CSF and determine the best contrast sensitivity (CS) curve. The best ACD value was acquired according to the CSF curve. The data form 10 cataract cases without retinal diseases were obtained and the postoperative ACD value was predicted using Holladay, Hoffer Q, SRK/T and the proposed method.</p><p><b>RESULTS</b>Consistency analysis of the results showed that all the ACD values predicated by the 4 methods fell in 95% consistency within the boundaries, and the differences in the largest absolute value between the 3 methods (Holladay, Hoffer Q, and SRK/T) and the proposed method were 0.73 mm, 0.65 mm, and 0.68 mm, and the calculation results of the mean value were 5.846 mm, 5.804 mm, and 5.825 mm. Clinically, the two methods were deemed to have good consistency.</p><p><b>CONCLUSION</b>The proposed method establishes a connection between the contrast sensitivity curve and ACD to allow better refraction adjustment for the patients.</p>

Application of 3D FIESTA sequence in magnetic resonance sialography for obstructive salivary diseases / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the value of 3D FIESTA sequence in magnetic resonance sialography (MRS) in the diagnosis of obstructive salivary diseases.</p><p><b>METHODS</b>Eleven patients with obstructive salivary diseases underwent MRS, and three-dimensional (3D) reconstruction and virtual endoscopic images of the salivary gland ducts were obtained after MRS data post-processing for comparison with those of sialoendoscopy.</p><p><b>RESULTS</b>The diagnostic accuracy of MRS was 72.7% for obstructive salivary diseases. The virtual endoscopy provided a visual field highly consistent with that by sialoendoscopy.</p><p><b>CONCLUSION</b>MRS is capable of visualizing the tracts of salivary glands. MR virtual endoscopy can provide sufficient morphological and pathological data for preoperative assessment of salivary operations with sialoendoscopy.</p>

Magnetic resonance imaging of bone and joint transfixed with stainless steel lag screws / 南方医科大学学报

To explore the method of displaying the bone and joint structures transfixed with stainless steel lag screws using magnetic resonance imaging (MRI), 2 patients whose knee joints (and ankle joint in one case) were transfixed with stainless steel underwent MRI with FSE-XL pulse sequence. The images clearly displayed the bones, ligaments and articular cartilage around the stainless steel materials, demonstrating the efficacy of FSE-XL pulse sequence in evaluation of the anatomical features of the bones and joints transfixed with stainless steel materials.