Improved visualization of the chorda tympani nerve using ultra-high-resolution computed tomography

Area of Science:

• Radiology
• Otolaryngology
• Anatomy

Background:

• Accurate anatomical understanding of the chorda tympani nerve (CTN) is crucial for preventing surgical complications in middle-ear procedures.
• Iatrogenic injuries to the CTN can lead to taste disturbances and other functional deficits.

Purpose of the Study:

• To compare the efficacy of ultra-high-resolution computed tomography (U-HRCT) versus conventional high-resolution CT (C-HRCT) in visualizing the CTN.
• To assess the visualization quality of different anatomical segments of the CTN using these two CT modalities.

Main Methods:

• Retrospective analysis of 59 temporal bones from 54 patients who underwent both C-HRCT and U-HRCT.
• The chorda tympani nerve was divided into three segments: posterior canaliculus, tympanic segment, and anterior canaliculus.
• Two neuroradiologists independently scored the visualization of each CTN segment on a four-point scale.

Main Results:

• U-HRCT demonstrated significantly higher visualization scores for all three CTN segments compared to C-HRCT (p < 0.01).
• The tympanic segment showed the greatest improvement in visualization with U-HRCT, although its score remained lower than the anterior and posterior segments.
• Specific scores for C-HRCT were: posterior (3.5±0.7), tympanic (1.6±0.6), anterior (3.1±0.7). U-HRCT scores were: posterior (3.9±0.2), tympanic (2.4±0.6), anterior (3.5±0.6).

Conclusions:

• Ultra-high-resolution CT offers superior visualization of the chorda tympani nerve.
• U-HRCT is particularly advantageous for visualizing the challenging tympanic segment of the CTN.
• Enhanced CT imaging of the CTN can improve surgical planning and reduce the risk of nerve injury.