Deep Learning Model for Grading Metastatic Epidural Spinal Cord Compression on Staging CT

Simple Summary Metastatic epidural spinal cord compression (MESCC) is a disastrous complication of advanced malignancy, and early diagnosis is important to prevent irreversible neurological injury. MRI is the mainstay of diagnosis for MESCC, but it is expensive, and routine screening of asymptomatic patients is not feasible. Staging CT studies are performed routinely as part of the cancer diagnosis and represent an opportunity for earlier diagnosis and treatment planning. In this study, we trained deep learning models for automatic MESCC classification on staging CT studies using spine MRI and manual radiologist labels as the reference standard. On a test set, the DL models showed almost-perfect interobserver agreement for the classification of CT spine images into normal, low, and high-grade MESCC, with kappas ranging from 0.873-0.911 (p < 0.001). The DL models (lowest kappa = 0.873, 95% CI 0.858-0.887) also showed superior interobserver agreement compared to two radiologists, including a specialist (kappa = 0.820, 95% CI 0.803-0.837) and general radiologist (kappa = 0.726, 95% CI 0.706-0.747), both p < 0.001. Background: Metastatic epidural spinal cord compression (MESCC) is a disastrous complication of advanced malignancy. Deep learning (DL) models for automatic MESCC classification on staging CT were developed to aid earlier diagnosis. Methods: This retrospective study included 444 CT staging studies from 185 patients with suspected MESCC who underwent MRI spine studies within 60 days of the CT studies. The DL model training/validation dataset consisted of 316/358 (88%) and the test set of 42/358 (12%) CT studies. Training/validation and test datasets were labeled in consensus by two subspecialized radiologists (6 and 11-years-experience) using the MRI studies as the reference standard. Test sets were labeled by the developed DL models and four radiologists (2-7 years of experience) for comparison. Results: DL models showed almost-perfect interobserver agreement for classification of CT spine images into normal, low, and high-grade MESCC, with kappas ranging from 0.873-0.911 (p < 0.001). The DL models (lowest kappa = 0.873, 95% CI 0.858-0.887) also showed superior interobserver agreement compared to two of the four radiologists for three-class classification, including a specialist (kappa = 0.820, 95% CI 0.803-0.837) and general radiologist (kappa = 0.726, 95% CI 0.706-0.747), both p < 0.001. Conclusion: DL models for the MESCC classification on a CT showed comparable to superior interobserver agreement to radiologists and could be used to aid earlier diagnosis.