Endovaginal coil for pelvic high-resolution magnetic resonance imaging of cervical cancer: a preliminary parameter optimization study.

ABSTRACT

Background: The diagnosis of early-stage cervical cancer through conventional magnetic resonance imaging (MRI) remains challenging, highlighting a greater need for pelvic high-resolution MRI (HR MRI). This study used our research team's endovaginal coil imaging to optimize scanning parameters and aimed to achieve HR MRI of the pelvis and determine its clinical value. Methods: Fifty participants were recruited prospectively for this cross-sectional study conducted at the First Affiliated Hospital of Chongqing Medical University from January 2023 to November 2023. Initially, 10 volunteers requiring pelvic imaging diagnosis underwent pelvic MRI with the endovaginal coil combined with a conventional external array coil to test and optimize the scanning parameters. Subsequently, 40 patients who were highly suspected or diagnosed with cervical cancer were randomly assigned to undergo an initial pelvic scan with an external array coil with subsequent examinations of both the conventional coil and the endovaginal coil. Two experienced radiologists performed quantitative analyses, measuring signals and calculating the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and contrast (C). They also conducted qualitative analyses, evaluating imaging artifacts, anatomical structures, and overall image quality. The paired sample t-test and Wilcoxon rank-sum test were conducted to compare the statistical differences between the two sets of images, while the intraclass correlation coefficient (ICC) and Kappa consistency tests were used to assess the measurement and scoring consistency between the two radiologists. Results: The optimized endovaginal images had higher mean SNR, CNR, and C values (18.62±7.85, 16.04±7.72, and 0.73±0.11, respectively) compared to the conventional images (6.77±2.36, 4.47±2.05, and 0.47±0.12, respectively). Additionally, the ratings for imaging artifacts, anatomical structures, and overall quality of the endovaginal images were all 4 [interquartile range (IQR) 4, 4]; meanwhile, the conventional images scored lower with ratings of 4 (IQR 3, 4), 3 (IQR 3, 3), and 3 (IQR 3, 3) for SNR, CNR, and C, respectively. All analysis results underwent paired-sample t-tests or Wilcoxon rank-sum tests between the two groups, yielding a P value <0.001. The optimized endovaginal images also showed improved resolution with a reconstructed voxel size of 0.11 mm3, and HR MRI was successfully achieved. The ICC values for the measurements were 0.914, 0.947, and 0.912, respectively, and for the ratings, the measurement was 0.923, indicating excellent consistency between the two physicians (ICC/Kappa value between 0.85 and 1.00). Conclusions: Endovaginal technology, which provides precise clinical information for the diagnosis of cervical cancer, provides straightforward operation and exceptional imaging quality, making it highly suitable for expanded clinical use.