CT versus MRI images in diagnosis of tibial plateau occult fractures

Abstract

Objective To explore the diagnostic values of CT and MRI images for tibial plateau occult fractures (TPOF). Methods From February 2013 to November 2015, 156 patients underwent X-ray examination for diagnosis of tibial plateau fracture. Those who had been suspected of having TPOF further took CT and MRI imaging. Their CT and MRI images were compared to evaluate the sensitivity, specificity and accuracy of diagnosing TPOF. The judgments were finally tested by the results of clinical di-agnoses and follow-ups. Results Of the 156 patients, 139 had fracture and 17 did not on clinical di-agnosis. X-ray detected obvious tibial plateau fracture in 61 cases, consistent with the clinical diagnosis. Of the other 95 cases who had further taken CT and MRI examinations, one was excluded as misdiagnosis by both CT and MRI. The sensitivity, specificity and accuracy of diagnosing TPOF on CT were 75.95% (60/79), 45.71% (16/35) and 80.00% (76/95); those on MRI were 98.73% (78/79), 94.12% (16/17) and 98.95% (94/95), respectively. The accuracy on MRI was significantly higher than on CT (P< 0.05). Four cases (6.67%, 4/60) were diagnosed as trabecular bone fracture on CT and 22 cases (28.20%, 22/78) on MRI. Of the 78 TPOF cases detected on CT and MRI, 56 cases were detected as having cortical fracture on clinical diagnosis. The sensitivity, specificity and accuracy of cortical fracture on CT were 100.00%(56/56), 100.00% (22/22) and 100.00% (78/78); those on MRI were 76.78% (43/56), 62.86% (22/35) and 83.33% (65/78), respectively. The accuracy of cortical fracture involvement was significant higher on CT than on MRI (P< 0.05). The 156 patients were followed up for one to 3 months. Of the 17 cases that had been diagnosed as having no fracture by CT or MRI, one was diagnosed clinically as trabecular bone fracture due to porosis found at one-month follow-up while the other 16 were finally diagnosed as soft tissue injury. The CT and MRI imaging diagnoses of the 139 cases of TPOF were in accordance with the eventual clinical diag-noses. Conclusions CT has a higher accuracy rate than MRI in diagnosing TPOF involving cortical bone. MRI can be the first preferred screening method when there is a doubt about the diagnosis of TPOF. CT combined with MRI may have a high diagnostic value for TPOF. Key words: Diagnosis, computer-assisted; Tibial fractures; Knee joint