Diffusion Tensor Imaging Studies on Recovery of Injured Optic Radiation: A Minireview

Visual Pathway Recovery Post Pituitary Adenoma Surgery: Insights from Retinal Structure, Vascular Density, and Neural Conduction Analysis

INTRODUCTION

This study investigates how surgery for pituitary adenoma (PA) affects the visual pathway, examining changes in the retina, blood vessel density, and nerve function. Since PAs often impair vision as a result of their location near visual structures, this research is key to understanding and improving vision recovery after surgery.

METHODS

Our study is based on a retrospective analysis of the historical data of 28 patients diagnosed with pituitary adenomas. We conducted assessments by reviewing preoperative and postoperative imaging records. These included optical coherence tomography (OCT) for retinal structure analysis, diffusion tensor imaging (DTI) for neural transmission evaluation, and optical coherence tomography angiography for assessing blood vessel density. These tools allowed for a detailed understanding of the structural and functional changes within the visual pathway following PA surgery.

RESULTS

OCT findings show postoperative changes in the eye: thinning in average and nasal circumpapillary retinal nerve fiber layer, thickening in macular central 1 mm inner plexus layer, ganglion cell complex, and nasal retinal nerve fiber layer. DTI reveals increased fractional anisotropy (FA) in the left optic chiasm and posterior optic nerve, decreased mid-segment optic nerve FA, and increased apparent diffusion coefficient (ADC) in the right optic chiasm and nerve segments. Early postoperative reduction in radial peripapillary capillaries plexus density is noted. Preoperative ganglion cell layer (GCL) thickness correlates with postoperative visual radiation FA and ADC values, especially in the inferior quadrant. A negative correlation exists between preoperative GCL thickness and postoperative visual field mean defect values, particularly on the temporal side and superior inner ring. All changes are statistically significant (P < 0.05).

CONCLUSIONS

The study finds that surgery for PA has varied effects on vision. Early post surgery, there are changes in the retina and nerve signals. Macular GCL thickness before surgery might predict early visual recovery, influencing future research and treatment for vision issues related to PA.

Applications of diffusion tensor imaging integrated with neuronavigation to prevent visual damage during tumor resection in the optic radiation area

Background

Intracranial tumors involving the temporo-occipital lobe often compress or destroy the optic radiation (OpR), resulting in decreased visual function. The aim of this study is to explore the value of diffusion tensor imaging (DTI) tractography integrated with neuronavigation to prevent visual damage when resecting tumors involving the OpR and find potential factors affecting patients’ visual function and quality of life (QOL).

Methods

Our study is a cross-sectional study that included 28 patients with intracranial tumors in close morphological relationship with the OpR recruited between January 2020 and February 2022. The surgical incision and approach were preoperatively designed and adjusted according to the DTI tractography results and visual function scores. All patients underwent examinations of visual acuity (VA) and visual field index (VFI) and completed visual function and QOL scales at admission and 2 months after discharge. Logistic regression and linear regression analysis were conducted to evaluate clinical factors potentially affecting pre/postoperative OpR morphology, VA, VFI, visual function, and QOL.

Results

Lesion size was the main factor found to affect visual function (β = -0.74, 95%CI: -1.12~-0.36, P = 0.05), VA (left: β = -0.11, 95%CI: -0.14~-0.08, P < 0.001; right: β = -0.15, 95%CI: -0.17~-0.13, P < 0.001), and VFI (left: β = -0.11, 95%CI: -0.14~-0.08, P < 0.001; right: β = -0.14, 95%CI: -0.16~-0.12, P < 0.001). Lesion size, edema, and involvement of the lateral ventricle temporal horn were factors affecting OpR morphology and QOL. The 28 patients showed significantly improved VA, VFI, visual function, and QOL results (P < 0.05) 2 months after discharge.

Conclusions

Combining DTI of OpR mapping and microscopic-based neuronavigation aided precise mapping and thus preservation of visual function in patients undergoing tumor resection. Potential clinical factors affecting patients’ visual function and QOL scores were identified which are useful for assessing a patient’s condition and predicting prognosis.