To evaluate the clinical application value of CT multiplanar reconstruction (MPR) technology in the preoperative differentiation of inguinal hernia types and prediction of incarceration risk, and to provide a reference for optimizing the clinical preoperative evaluation process.

This was a single-center retrospective diagnostic accuracy study. A total of 102 patients with inguinal hernia (involving 109 hernia sacs) confirmed by surgery at the 73rd Group Army Hospital of the Chinese People's Liberation Army Army from January 2023 to April 2025 were included. All patients underwent preoperative multi-slice spiral CT (MSCT) plain scan and MPR (coronal, oblique coronal, and sagittal planes). The display effects of different reconstruction planes on key anatomical structures in the inguinal region were analyzed, characteristic imaging signs were identified, and the hernia sac neck ratio (the ratio of the maximum width of the hernia sac to the width of the hernia sac neck) was measured. Using surgical findings as the gold standard, receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance for hernia classification and the predictive value for incarceration risk.

The complete visualization rate of the inguinal ligament using oblique coronal MPR was significantly higher than that using coronal reconstruction (56.88% vs. 21.10%), while the non-visualization rate (14.68%) was significantly lower than that of coronal reconstruction (40.37%) (P<0.05). The area under the curve (AUC) values of the "lateral crescent sign" and the "direct inguinal hernia triangle filling sign" for differentiating direct from indirect inguinal hernia were 0.812 and 0.843, respectively, while the AUC value of the "femoral triangle filling sign" for distinguishing femoral hernia from other types of hernia was 0.831 (P<0.05). The incarceration rate of femoral hernia (72.00%, 18/25) was significantly higher than that of indirect hernia (14.58%, 7/48) and direct hernia (16.67%, 6/36) (χ²=36.241, P<0.001). The optimal cutoff values of the hernia sac neck ratio for predicting incarceration in indirect, direct, and femoral hernias were 2.40, 3.70, and 3.30, respectively, with corresponding AUC values of 0.852, 0.876, and 0.791.

CT MPR technology can clearly delineate the anatomical structures of the inguinal region. Its characteristic imaging signs enable accurate differentiation of various types of inguinal hernias, and the hernia sac neck ratio can effectively quantify and predict the risk of incarceration, thereby providing a reliable basis for individualized clinical treatment planning.