Objective: To investigate the diagnostic value of magnetic resonance imaging (MRI) in patients with Modic changes and endplate sclerosis of the lumbar spine. Methods: A total of 66 patients with lumbar spine diseases who underwent MRI and CT diagnostic examinations at the hospital from May 2024 to April 2025 were included in this study. The MRI findings of Modic changes were compared between Type I and Type II patients, and the presence or absence of endplate sclerosis signals and the HU value ratio on CT were analyzed. The pathological characteristics of Modic changes in Type I and Type II patients were observed. The imaging features of Modic changes in patients with lumbar spine diseases were analyzed. Results: Modic changes were present in 34 patients, with a total of 204 endplates evaluated, of which 74 were affected. MRI classification showed: Type I in 8 cases (10.81%), Type I/II mixed in 10 cases (13.51%), Type II in 51 cases (68.92%), and Type II/III mixed in 5 cases (6.76%). In CT reconstruction images, 26 endplates with Modic changes on MRI showed sclerosis in the vertebral body, presenting high-density sclerotic features. These sclerotic areas did not exhibit distinct signal characteristics on MRI but pathologically demonstrated Type II Modic changes concurrently with fatty degeneration and sclerosis; In patients with Modic changes of Type I and Type II, regardless of the presence or absence of endplate sclerosis, the sagittal T1/T2 signal intensity ratio showed no statistically significant difference (P > 0.05). However, the HU value ratio in Type II changes with sclerotic regions (2.74 ± 0.61) was significantly higher than that in regions without sclerosis (1.16 ± 0.23), with a statistically significant difference (P < 0.05). Conclusion: CT reconstruction images of patients with lumbar Modic changes clearly demonstrate endplate sclerosis, a phenomenon closely associated with the bone marrow repair process. MRI has limited sensitivity for detecting sclerosis, potentially due to the following factors: first, differences in the radiographic characterization of endplate mineral content; second, the specific influence of different Modic types on signal intensity. This suggests that MRI classification should be combined with CT features for comprehensive interpretation.