The Accuracy of Sonography for Evaluation of Internal Derangement of the Temporomandibular Joint in Asymptomatic Elementary School Children: Comparison with MR and CT
Takafumi Hayashi
,a,
Jusuke Itoa,
Jun-ichi Koyamaa and
Kazuhiro Yamadaa
a From the Departments of Oral and Maxillofacial Radiology (T.H., J.I. J-i.K.) and Orthodontics (K.Y.), Faculty of Dentistry, Niigata University.
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FIG 1. A schematic drawing of the scanning plane of the transducer in a transverse direction running parallel to the Camper line intersecting the ala of the nose and the tragus of the ear
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FIG 2. A transverse section of sonography of the normal right TMJ obtained while the patient was in the closed-mouth position. Note hyperechoic line (arrowhead) running lateral and parallel to the lateral surface (arrow) of the mandibular condyle, indicating the articular capsule. We measured the distance between the articular capsule and the lateral surface of the mandibular condyle (between the apexes of the arrow and arrowhead) on the display of the sonographic equipment
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FIG 3. 10-year-old girl.
A, A transverse section of sonography of the right TMJ obtained while the patient was in the closed-mouth position. Note a hyperechoic line (arrowhead) running lateral and parallel to the lateral surface (arrow) of the mandibular condyle, indicating the articular capsule. The distance between the articular capsule and the lateral surface of the mandibular condyle is 4 mm.
B, A sagittal proton density–weighted image of the right TMJ obtained while the patient was in the closed-mouth position. Note the posterior band of the articular disk located anterior to the mandibular condyle (anterior disk displacement). The evaluation of the disk displacement on A is a true-positive result.
C, A transverse section of sonography of the left TMJ obtained while the patient was in the closed-mouth position. The distance between the articular capsule (arrowhead) and the lateral surface (arrow) of the mandibular condyle is 3 mm.
D, A sagittal proton density–weighted image of the left TMJ obtained while the patient was in the closed-mouth position. Note the posterior band of the articular disk located superior to the mandibular condyle (normal superior position). The evaluation of the disk displacement on C is a true-negative result.
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FIG 4. Same patient as shown in figure 3. A series of continuous axial T1-weighted images at the level of the TMJ obtained while the patient was in the closed-mouth position. Note a part of anterolaterally displaced disk (arrows) covering the lateral surface of the right mandibular condyle and a part of widened articular capsule (arrowhead) adjacent to the lateral surface of the condyle
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FIG 5. 10-year-old boy.
A, A transverse sonographic section of the left TMJ obtained while the patient was in the closed-mouth position. The distance between the articular capsule (arrowhead) and the lateral surface (arrow) of the mandibular condyle is 5 mm.
B, A transverse CT section at the level of the mandibular condyle obtained while the patient was in a closed-mouth position. Note the hyperdense area in front of the left mandibular condyle indicating the anteriorly dislocated articular disk. Disk displacement on A is a true-positive result.
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