The Diagnostic Accuracy of MRI to Evaluate Acute Lisfranc Joint Injuries: Comparison With Direct Operative Observations.

BACKGROUND: Early diagnosis is important in patients with Lisfranc joint injury to avoid subsequent complications. As the ligaments in the Lisfranc joint are relatively small and course obliquely, isotropic 3-dimensional (3D) magnetic resonance imaging (MRI) can be beneficial to evaluate ligament injury. The purpose of this study was to investigate the diagnostic accuracy of MRI, including isotropic 3D MRI for acute injury of the Lisfranc joint, especially of the interosseous C1-M2 ligament (Lisfranc ligament), the dorsal C1-M2 ligament (dorsal ligament), and the interosseous C1-C2 ligament, compared with direct operative observations. METHODS: This retrospective review identified 27 patients who had undergone MR examination for acute Lisfranc joint injury followed by surgery. We reviewed the operative reports that described the Lisfranc, dorsal, and interosseous C1-C2 ligaments. All patients underwent an MRI, including a 2D oblique plane image parallel to the Lisfranc ligament and an isotropic 3D MRI. An image analysis of the integrity of the 3 ligaments and other associated injuries was performed. The diagnostic accuracy of MRI was analyzed using operative findings as a reference standard. RESULTS: Lisfranc and dorsal ligament injuries were identified on MRI in all patients. MRI depicted disruption of the interosseous C1-C2 ligament in 12 patients. MRI diagnostic accuracy for detection of Lisfranc, dorsal, and interosseous C1-C2 ligaments was 100% (95% CI 0.82-1.0), 74% (95% CI 0.54-0.89), and 70% (95% CI 0.50-0.86), respectively. CONCLUSION: MRI with oblique planes parallel to the Lisfranc ligament and isotropic 3D MRI was reliable for detecting Lisfranc ligament injury, whereas MRI findings of the dorsal and interosseous C1-C2 ligaments were less consistent with operative observations. LEVEL OF EVIDENCE: Level IV, case series.

Temporal Bone Trauma: Typical CT and MRI Appearances and Important Points for Evaluation.

Temporal bone trauma is frequently encountered in the emergency department. Technologic advances have enabled timely acquisition of thin-section images and multiplanar reconstructions such that temporal bone anatomy can be evaluated in great detail, with excellent delineation of fractures. The temporal bone is composed of a myriad of tiny structures, including many fissures and canals, that must be distinguished from true fractures. In addition, injury to important structures may result in serious complications such as hearing loss, dizziness, imbalance, perilymphatic fistula, cerebrospinal fluid leakage, facial nerve paralysis, and vascular injury. Structures that should be examined include the tympanic cavity and tegmen, the ossicular chain, the bony labyrinth, the facial canal, the internal carotid artery, the jugular foramen and venous sinuses, and the intracranial contents. Radiologists should be familiar with the anatomy of the temporal bone and be able to describe any pathologic findings and make suggestions to referring clinicians to guide management and determine the prognosis. The authors describe the typical CT and MRI appearances of temporal bone trauma, entities that mimic this injury and thus must be differentiated, and compulsory points for evaluating clinically relevant associated complications. Instruction is provided for acquiring the diagnostic skills necessary to report suggested injury status, complications, and likely sequelae to clinicians.©RSNA, 2020.

MR Imaging Evaluation of the Lisfranc Ligament in Cadaveric Feet and Patients With Acute to Chronic Lisfranc Injury.

BACKGROUND: Magnetic resonance (MR) imaging is known to be useful to demonstrate Lisfranc ligament injury. There are few studies that report differences in MR imaging findings of acute or chronic Lisfranc ligament injuries. We applied oblique MR imaging planes parallel to the Lisfranc ligament for better visualization of the entire course of the ligament and assessed the detailed MR imaging appearances of the Lisfranc ligament in cadavers and patients with presumed Lisfranc injuries. METHODS: Twelve preserved cadaveric feet were examined using a small-diameter surface coil. Long axis, oblique sagittal, and oblique short axis cross sections parallel to the Lisfranc ligament, dorsal ligament, and plantar ligament were obtained. Twenty-six MR examinations from 23 patients with suspected Lisfranc joint injuries were evaluated. RESULTS: In the cadaveric study, the Lisfranc ligament was satisfactorily visible along its entire course in a single slice on long axis and oblique sagittal MR images. The dorsal ligament and the plantar ligament were visible separately from the Lisfranc ligament in oblique sagittal and oblique short axis planes. In the patient study, 11 MR examinations led to diagnoses of complete tears of the Lisfranc ligament that were acute injuries (3-21 days after trauma) mostly associated with disruption of the dorsal and plantar ligaments. Nine studies led to diagnoses of incomplete tears of the Lisfranc ligament that were chronic injuries (2-14 months after trauma). Recovery of the continuity of the disrupted ligament was observed in 3 patients. CONCLUSION: MR imaging demonstrated the integrity of the ligaments and was useful for diagnosing an acute Lisfranc injury. Fibrous healing of the torn ligament was observed in a chronic injury.