Use of DKI may be feasible for common odontogenic lesions. A combination of DKI parameters can be expected to increase the accuracy of its diagnostic ability compared with ADC. J. Magn. Reson. Imaging 2016;44:1565-1571.

Appropriate monitors are needed for radiographic diagnosis on monitor screens.

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FLAIR sequences provide a high signal in patients having painful TMJ, and it suggests that retrodiscal tissue in painful TMJ contains elements such as protein.

The accurate diagnosis of vascular anomalies (VAs) is considered a challenging endeavor. Misdiagnosis of VAs can lead clinicians in the wrong direction, such as the performance of an unnecessary biopsy or inappropriate surgical procedures, which can potentially lead to unforeseen consequences and increase the risk of patient injury. The purpose of the present study was to develop an approach for the diagnosis of VAs of the oral and maxillofacial region based on computed tomography (CT), magnetic resonance imaging (MRI) and dynamic contrast-enhanced MRI (DCE-MRI). In the present study, the CT and MR images of 87 VAs were examined, and the following imaging features were evaluated: Detectability of the lesion, the periphery of the lesion, the inner nature of the lesion, the density of the lesion on CT, the signal intensity of the lesion on MRI, the detectability of phleboliths and the shape of the lesion. A total of 29 lesions were further evaluated using the contrast index (CI) curves created from the DCE-MRI images. A diagnostic diagram, which is based on the imaging features of VAs and CI curve patterns, was subsequently extrapolated. The results obtained demonstrated that the VAs were detected more readily by MRI compared with CT, whereas the detectability of phleboliths was superior when using CT compared with MRI. VAs showed a propensity for homogeneous isodensity on CT, whereas, by contrast, they exhibited a propensity for heterogeneous hyperdensity on CE-CT. VAs also showed a propensity for homogeneous intermediate signal intensity when performing T1-weighted imaging (T1WI), heterogeneous high signal intensity when performing short tau inversion recovery MRI, and heterogeneous high signal intensity when performing fat-saturated CE-T1WI. The CI curves of VAs were found to exhibit a specific pattern: Of the 29 CI curves, 23 (79.3%) showed early weak enhancement, followed by a plateau leading up to 400-600 sec. An imaging-based diagnostic diagram was ultimately formulated. This diagram can act as an aid for radiologists when they are expecting to find a VA, and hopefully serve the purpose of simplifying the diagnostic process. Taken together, the findings of the present study indicated that DCE-MRI may be considered a useful tool for the diagnosis of VAs.

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: The purpose of this study was to clarify the validity of measuring the signal intensities of cortical bone CB and temporomandibular joint TMJ discs on magnetic resonance MR images for the diagnosis of TMJ disease. Two investigations were performed. In the rst investigation, MR images of 13 TMJs of volunteers were obtained using a multi spin-echo sequence. Echo time TE was increased from 10 msec to 200 msec in steps of 10 msec. The signal intensities of the CB of the condylar head, and the anterior AD and posterior PD bands of the TMJ disc were measured, and their attenuation patterns were compared. In the second investigation, clinical MR images of 30 TMJs from patients with suspected TMJ disorders were selected. Proton density-weighted images PDWIs and T2-weighted images T2WIs were obtained at TEs of 14 and 85 msec, respectively, using a double-echo fast spin-echo sequence. The signal intensities of CB, AD, and PD were measured and compared with that of the external auditory meatus air using a Bonferroni test. AD and PD showed nearly identical signal intensity attenuation patterns. The signal intensities of AD and PD were lower than CB at TEs longer than 20 msec although they were higher at TEs shorter than 20 msec. Clinical PDWIs and T2WIs showed similar results. The signal intensities of CB, AD, and PD were signi cantly higher than the external auditory meatus air in both PDWIs and T2WIs. CB and TMJ discs show characteristic signal intensities, suggesting that the signal intensity measurement of these structures is valid.