1992, The British Journal of Radiology, 65, 955-960
NOVEMBER 1992
VOLUME 65 NUMBER 779
The British Journal of Radiology Direct coronal computed tomography of the temporomandibular joint in patients with rheumatoid arthritis By P. Goupille, MD, B. Fouquet, MD, *P. Cotty, MD, tD. Goga, MD and J.-P. Valat, MD Departments of Rheumatology, *Neuroradiology and tMaxillofacial Surgery, University of Tours, Trousseau Hospital, 37044 Tours Cedex, France {Received 17 June 1991 and in final form 9 March 1992, accepted 6 May 1992) Keywords: Rheumatoid arthritis, Temporomandibular joint, Computed tomography Abstract. Direct coronal computed tomography (CT) of the temporomandibular joint (TMJ) was performed in 26 patients with rheumatoid arthritis (RA) and 26 control subjects. Erosions and cysts of the mandibular condyle had a significantly higher frequency in the RA group than in the control group (p < 0.05) but there was no significant difference in the incidence of other abnormalities. Bone changes were bilateral in RA. A wide range of CT abnormalities was present in patients with RA and in the control group. There are no CT abnormalities specific for RA, but the incidence of erosions and cysts of the mandibular condyle was significantly higher in the RA group and should suggest the diagnosis.
Reports on the extent of the involvement of the temporomandibular joint (TMJ) in rheumatoid arthritis (RA) differ widely. Clinical TMJ involvement in RA varies from 4.7% (Ragan, 1979) to 84% (Friez & Le Goc, 1982). The incidence of radiographic abnormalities on conventional radiography varies from 19 to 86% (Uotila, 1964; Ericson & Lundberg, 1967; Larheim et al, 1983; Syrjanen, 1985). There has been one previous direct coronal computed tomography (CT) study of the TMJ in adult RA (Avrahami et al, 1989), which found bone lesions in 68% of the joints. More recently, Larheim and Kolbenstvedt (1990) reported 70% of TMJ abnormalities on axial CT in patients with RA. These variations might be due to different types of examination, the selection of patients, the use of different criteria for classifying joint involvement and the presence or absence of a control group which could lead to an overestimation of the frequency of TMJ involvement in RA. Radiological examination of the TMJ is difficult owing to its location and its relation to other cranial structures. The aims of this study were: (1) To investigate the frequency, character and severity of TMJ bone changes on direct coronal CT in RA. The significance of thefindingswas evaluated by comparison with a control group; (2) To determine the specific lesions of RA on TMJ. Materials and methods
RA group 26 patients with clinically established RA based on the criteria of the American Rheumatism Association were included. The mean age of the patients was 62.1 years (SD 11.8). The female to male ratio was 22:4. The Address correspondence to Dr P. Goupille. Vol. 65, No. 779
mean duration of the disease was 105 months (SD 133 months, range 0.5-51 years). Control group 26 patients (mean age 62 years, SD 11.4 years) without general joint disease and admitted for sciatica were included. The selection was based on age and sex to match the RA group. Ethical committee permission was granted and informed consent was obtained after the nature of the procedure had been fully explained. Coronal CT examination of the TMJ 26 RA and 26 control subjects underwent coronal CT examination of the TMJ. The patients who had no evidence of cervical spine instability on neck radiography were examined in the supine position, with hyperextension of the neck. The radiographic beam was directed cephalad through the TMJ by a 20° tilt of the gantry. CT sections were selected on the lateral scout view, making certain that each condyle was imaged (Fig. 1). Contiguous 1.5 mm thick scans were obtained and a retrospective target reconstruction was made with a hard filter. Interpretation was made on a computer console with bone and soft-tissue windows settings. All CT scans were examined "blind" and in random order by a single observer. In each CT scan, the shape (convex, concave or flattened) and the height (normal, hypoplasic or hyperplasic) of the mandibular condyle were estimated. The presence or absence of the following features was evaluated: flattening of the articular eminence, bone demineralization, erosions and bone cysts of the mandibular condyle and glenoid fossa (none, one, two or more), condylar head resorption (none, mild, severe), mandibular fracture, decreased 955
P. Goupille, B. Fouquet, P. Cotty, D. Coga and J.-P. Valat
Figure 1. CT scan showing coronal section.
joint space (less than 0.5 mm), bony ankylosis, temporal or mandibular subchondral sclerosis, osteophytosis and calcification of the articular disc. Statistics For each parameter, the significance of differences between the two groups was analysed by means of the x2 test. The level of statistical significance was p < 0.05, otherwise denoted NS. Results
Only five control subjects were free of bone changes; most (20) had flattening of the articular eminence. Changes in condylar shape, erosions and cysts of the mandibular condyle and condylar head resorption were more frequent in the RA group than the control group (Table I). A statistically significant difference was only found for erosions and cysts of the mandibular condyle (Table I). Osteophytic changes were more frequent in
Figure 2. Four stages of bone changes of the mandibular condyle on CT in RA. e, erosion; c, cysts; s, sclerosis.
956
Figure 3. Extensive erosion of the condylar surface of the mandibular condyle in RA.
the RA group than in the control group, without a statistically significant difference (Table I). Erosions and bone cysts were demonstrated in 88% of the TMJ in RA compared with 58% in the control group (p < 0.05). In most cases, the bone changes in RA were bilateral.
Figure 4. Bony changes of the glenoid fossa on CT in RA. E, erosions; CT, glenoid fossa; CM, mandibular condyle.
The British Journal of Radiology, November 1992
CT of the temporomandibular joint in RA
Figure 5. Osteophyte arising from the glenoid fossa in RA.
Bone changes of the mandibular condyle among the RA group were classified into four grades (Fig. 2): Grade 1: erosions of the subchondral bone. Grade 2: erosions with deep cysts. Grade 3: extensive erosion of the condylar surface (Fig. 3). Grade 4: flattening and resorption of the condylar surface.
Figure 6. Meniscus calcification in RA (arrow).
Bone changes of the glenoid fossa were less frequent (Table I). Erosions and cysts involved either the floor or the internal part of the glenoid fossa (Fig. 4).
Table I. Bone changes among 26 patients with RA and 26 control subjects on coronal CT of the TMJ RA (n = 26)
Control (« = 26) Right TMJ
Left TMJ
Right TMJ
Left TMJ
19
17
20
17
-p < 0.001Erosions of the mandibular condyle -p< 0.001p < 0.001Cysts of the mandibular condyle
7 -p < O'.OOl -
Condylar head resorption Deformity of the mandibular condyle Osteophytes arising from mandibular condyle Erosions of the glenoid fossa Cysts of the glenoid fossa Flattening of the articular eminence Meniscus calcification Decreased joint space
Vol. 65, No. 779
5 11 5
4 12 3
10 17 6
11 20 7
6 5 19 4 13
6 4 18 1 13
9 7 14 4 12
9 10 16 1 9
957
P. Goupille, B. Fouquet, P. Cotty, D. Coga and J.-P. Valat
Figure 7. Calcification adjacent to the lateral aspect of the mandibular condyle in RA (arrow).
Figure 8. Medial osteophyte of the mandibular condyle in a "teardrop" configuration in RA (arrow).
Six patients with RA had large destructive lesions: (a) flattening of the mandibular condyle and glenoid fossa with erosions of the articular surfaces, sclerosis and decreased joint space; (b) multiple cysts of the articular surfaces, erosions, more decreased joint space and changes of the glenoid fossa; (c) osteophyte arising from the glenoid fossa (Fig. 5); and (d) an osteocartilaginous loose body was noted in one case. Intra-articular calcification was also seen: meniscal calcification in six cases (Fig. 6); larger intra-articular calcification in one case; and calcification along the outer part of the mandibular condyle in one case (Fig. 7). Ankylosis of the TMJ in RA was observed in two TMJs. Other changes (one in each case) were noted: (a) decreased joint space and sclerosis of the articular surfaces; (b) "teardrop" osteophyte of the mandibular condyle (Fig. 8); (c) osseous bridging between the glenoid fossa and the mandibular condyle; and (d) bone sequestra within an area of bone sclerosis (Fig. 9).
and the meniscal position (Helms et al, 1984a; Manzione et al, 1984; Sartoris et al, 1984; Thompson et al, 1984). The sagittal view may give more information regarding the position of the meniscus than the coronal view (Helms et al, 1984b; Manzione et al, 1984a; Manco et al, 1985; Raustia et al, 1985), but the coronal plane allows better visualization of the osseous elements of the TMJ (Horowitz et al, 1982; Larheim & Kolbenstvedt, 1984; Reck & Fielding, 1986). Axial sections cut the articular surfaces of the condylar head and glenoid fossa tangentially, precluding the demonstration of fine bone changes (Avrahami et al, 1989). The aim of our study was to estimate the osseous involvement of TMJ in RA, so the coronal plane was used. Erosions and cysts of the TMJ in RA on coronal CT were frequent in our study (88%). The only previous coronal CT study of the TMJ in adult RA found 68% of bone lesions of various degrees, but without a control group (Avrahami et al, 1989). Contrary to some other studies obtained with conventional radiography or tomography (Mayne & Hatch, 1969; Blair, 1973; Trenwith & Beale, 1977; Syrjanen, 1985), some bone changes were equally distributed in the two groups in our study, namely flattening of the
Discussion
Since Suarez et al (1980) made their preliminary study on CT of the TMJ, the technique has rapidly proved to be highly accurate for evaluating both bony changes 958
The British Journal of Radiology, November 1992
CT of the temporomandibular joint in RA high resolution computed tomography of the temporomandibular joints in patients with rheumatoid arthritis. Journal of Rheumatology, 16, 298-301. BLANC, P., 1959. L'atteinte de l'articulation temporo-maxillaire au cours du rhumatisme inflamatoire chronique. Cahiers Odonto-stomatologiques, 9, 17-73. CHALMERS, I. M. & BLAIR, G. S., 1973. Rheumatoid arthritis of
the temporomandibular joint. A clinical and radiological study using circular tomography. Quarterly Journal of Medicine (New series), 42, 369-386. ERICSON, S. & LUNDBERG, M., 1967. Alterations in the TMJ at
various stages of rheumatoid arthritis. Acta Rheumatologica Scandinavica, 13, 257-274. FRIEZ, L. & LE GOC, Y., 1982. Articulations temporomaxillaires et polyarthrite rhumatoi'de. Rhumatologie, 34, 193-196. HELMS, C. A., VOGLER, J. B. & MORRISH, R. B., 1984a.
Diagnosis by computed tomography of temporomandibular joint meniscus displacement. Journal of Prosthetic Dentistry, 51, 544-547. HELMS, C. A., VOGLER, J. B., MORRISH, R. B., GOLDMAN,
S. M., CAPRA, R. E. & PROCTOR, E., 1984b. Temporo-
mandibular joint internal derangements: CT diagnosis. Radiology, 152, 459-462. HOROWITZ,
I.,
AVRAHAMI,
E.
&
MINTZ,
S.
S.,
1982.
Demonstration of condylar fractures of the mandible by computed tomography. Oral Surgery, Oral Medicine, Oral Pathology, 54, 263-268. LARHEIM, T. A. & KOLBENSVEDT, A., 1984. High-resolution
computed tomography of the osseous temporomandibular joint. Some normal and abnormal appearances. Acta Radiologica, 25, 465^69. LARHEIM, T. A. & KOLBENSTVED, A., 1990. Osseous temporo-
Figure 9. Bone sequestrum (arrow) within a sclerotic area of the mandibular condyle in RA.
articular eminence, decreased joint space, calcification of the articular disc, osteophytosis and subchondral sclerosis. Erosions and changes in the shape of the mandibular condyle have been described as osteoarthritic lesions (Toller, 1973, 1974; Rasmussen, 1981). We found that the lesions most suggestive of RA were erosions and cysts of the mandibular condyle, and this agrees with some previous papers (Blanc, 1959; Mayne & Hatch, 1969; Chalmers & Blair, 1973). Bilateral involvement of the TMJ was more common in the RA group than in the control group, and this also agrees with previous papers (Resnick, 1974; Lowry, 1975; Seymour et al, 1975). In conclusion, coronal CT scanning is an accurate technique for evaluating bone changes in the TMJ. Erosions and cysts of the mandibular condyle and the bilateral nature of these abnormalities are suggestive of RA. Acknowledgment We wish to thank Mrs S. Gardes for typing the manuscript. References AVRAHAMI, E., SEGAL, R., SOLOMON, A., GARTI, A., HOROWITZ, I., CASPI, D., WIGLER, I. & YARON, M., 1989. Direct coronal
Vol. 65, No. 779
mandibular joint abnormalities in rheumatic disease. Computed tomography versus hypocycloidal tomography. Acta Radiologica, 31, 383-387. LARHEIM, T. A., STORHAUG, K. & TVEITO, L., 1983. Temporo-
mandibular joint involvement and dental occlusion in a group of adults with rheumatoid arthritis. Acta Odontologica Scandinavica, 41, 301-309. LOWRY, J. C , 1975. Psoriatic arthritis involving the temporomandibular joint. Journal of Oral Surgery, 33, 206-208. MANCO, L. G., MESSING, S. G., BUSINO, L. J., FASULO, C. P. &
SORDILL, W. C , 1985. Internal derangements of the temporomandibular joint evaluated with direct sagittal CT: a prospective study. Radiology, 157, 407-412. MANZIONE, J. V., KATZBERG, R. W., BRODSKY, G. L., SELTZER,
S. E. & MELLINS, H. Z., 1984. Internal derangement of the temporomandibular joint: diagnosis by direct sagittal computed tomography. Radiology, 150, 111-115. MAYNE, J. G. & HATCH, G. S., 1969. Arthritis of the temporo-
mandibular joint. Journal of the American Dental Association, 79, 125-130. RAGAN, C , 1979. General management of rheumatoid arthritis. Journal of the American Medical Association, 141, 124. RASMUSSEN, O. C , 1981. Description of population and progress of symptoms in a longitudinal study of temporomandibular arthropathy. Scandinavian Journal of Dental Research, 89, 196-203. RAUSTIA,
A.
M.,
PYHTINEN,
J.
&
VIRTANEN,
K.,
1985.
Examination of the temporomandibular joint by direct sagittal computed tomography. Clinical Radiology, 36, 291-296. RECK, S. F. & FIELDING, A. F., 1986. Computed tomography in
temporomandibular joint diagnosis. New York State Dental Journal, 52, 37-40.
959
P. Goupille, B. Fouquet, P. Cotty, D. Coga and J.-P. Valat RESNICK, D., 1974. TMJ involvement in ankylosing spondylitis. Comparison with rheumatoid arthritis and psoriasis. Radiology, 112, 587-591.
THOMPSON, J. R., CHRISTIANSEN, E., HASSO, A. N. & HINSHAW,
temporomandibular joint: true sagittal computed tomography with meniscus visualization. Radiology, 150, 250-254.
D. B., 1984. TMJ: high-resolution computed tomographic evaluation. Radiology, 150, 105-110. TOLLER, P. A., 1973. Osteoarthritis of the mandibular condyle. British Dental Journal, 124, 223-231. TOLLER, P. A., 1974. Temporomandibular arthropathy. Proceedings of the Royal Society of Medicine, 67, 153-159.
SEYMOUR, R. L., CROUSE, V. L. & IRBY, W. B., 1975. Temporo-
TRENWITH, J. A. & BEALE, G., 1977. Rheumatoid arthritis in
mandibular ankylosis secondary to rheumatoid arthritis. Oral Surgery, Oral Medicine, Oral Pathology, 40, 584-589.
the temporomandibular joint. New Zealand Dental Journal, 73, 195-199. UOTILA, E., 1964. The temporomandibular joint in adult rheumatoid arthritis: a clinical and roentgenologic study. Acta Odontologica. Scandinavica, 22 (suppl. 39), 22.
SARTORIS, D. J., NEUMANN, C. H. & RILEY, R. W., 1984.
The
SUAREZ, F., BHUSSRY, B., NEFF, P., HUANG, H. & VAUGHN, D.,
1980. A preliminary study of computerized tomography of the temporomandibular joint. Compendium of Continuing Education in Dentistry, 1, 217-222. SYRJANEN, S. M., 1985. The temporomandibular joint in rheumatoid arthritis. Acta Radiologica, 26, 235-243.
960
The British Journal of Radiology, November 1992
NOVEMBER 1992
VOLUME 65 NUMBER 779
The British Journal of Radiology Direct coronal computed tomography of the temporomandibular joint in patients with rheumatoid arthritis By P. Goupille, MD, B. Fouquet, MD, *P. Cotty, MD, tD. Goga, MD and J.-P. Valat, MD Departments of Rheumatology, *Neuroradiology and tMaxillofacial Surgery, University of Tours, Trousseau Hospital, 37044 Tours Cedex, France {Received 17 June 1991 and in final form 9 March 1992, accepted 6 May 1992) Keywords: Rheumatoid arthritis, Temporomandibular joint, Computed tomography Abstract. Direct coronal computed tomography (CT) of the temporomandibular joint (TMJ) was performed in 26 patients with rheumatoid arthritis (RA) and 26 control subjects. Erosions and cysts of the mandibular condyle had a significantly higher frequency in the RA group than in the control group (p < 0.05) but there was no significant difference in the incidence of other abnormalities. Bone changes were bilateral in RA. A wide range of CT abnormalities was present in patients with RA and in the control group. There are no CT abnormalities specific for RA, but the incidence of erosions and cysts of the mandibular condyle was significantly higher in the RA group and should suggest the diagnosis.
Reports on the extent of the involvement of the temporomandibular joint (TMJ) in rheumatoid arthritis (RA) differ widely. Clinical TMJ involvement in RA varies from 4.7% (Ragan, 1979) to 84% (Friez & Le Goc, 1982). The incidence of radiographic abnormalities on conventional radiography varies from 19 to 86% (Uotila, 1964; Ericson & Lundberg, 1967; Larheim et al, 1983; Syrjanen, 1985). There has been one previous direct coronal computed tomography (CT) study of the TMJ in adult RA (Avrahami et al, 1989), which found bone lesions in 68% of the joints. More recently, Larheim and Kolbenstvedt (1990) reported 70% of TMJ abnormalities on axial CT in patients with RA. These variations might be due to different types of examination, the selection of patients, the use of different criteria for classifying joint involvement and the presence or absence of a control group which could lead to an overestimation of the frequency of TMJ involvement in RA. Radiological examination of the TMJ is difficult owing to its location and its relation to other cranial structures. The aims of this study were: (1) To investigate the frequency, character and severity of TMJ bone changes on direct coronal CT in RA. The significance of thefindingswas evaluated by comparison with a control group; (2) To determine the specific lesions of RA on TMJ. Materials and methods
RA group 26 patients with clinically established RA based on the criteria of the American Rheumatism Association were included. The mean age of the patients was 62.1 years (SD 11.8). The female to male ratio was 22:4. The Address correspondence to Dr P. Goupille. Vol. 65, No. 779
mean duration of the disease was 105 months (SD 133 months, range 0.5-51 years). Control group 26 patients (mean age 62 years, SD 11.4 years) without general joint disease and admitted for sciatica were included. The selection was based on age and sex to match the RA group. Ethical committee permission was granted and informed consent was obtained after the nature of the procedure had been fully explained. Coronal CT examination of the TMJ 26 RA and 26 control subjects underwent coronal CT examination of the TMJ. The patients who had no evidence of cervical spine instability on neck radiography were examined in the supine position, with hyperextension of the neck. The radiographic beam was directed cephalad through the TMJ by a 20° tilt of the gantry. CT sections were selected on the lateral scout view, making certain that each condyle was imaged (Fig. 1). Contiguous 1.5 mm thick scans were obtained and a retrospective target reconstruction was made with a hard filter. Interpretation was made on a computer console with bone and soft-tissue windows settings. All CT scans were examined "blind" and in random order by a single observer. In each CT scan, the shape (convex, concave or flattened) and the height (normal, hypoplasic or hyperplasic) of the mandibular condyle were estimated. The presence or absence of the following features was evaluated: flattening of the articular eminence, bone demineralization, erosions and bone cysts of the mandibular condyle and glenoid fossa (none, one, two or more), condylar head resorption (none, mild, severe), mandibular fracture, decreased 955
P. Goupille, B. Fouquet, P. Cotty, D. Coga and J.-P. Valat
Figure 1. CT scan showing coronal section.
joint space (less than 0.5 mm), bony ankylosis, temporal or mandibular subchondral sclerosis, osteophytosis and calcification of the articular disc. Statistics For each parameter, the significance of differences between the two groups was analysed by means of the x2 test. The level of statistical significance was p < 0.05, otherwise denoted NS. Results
Only five control subjects were free of bone changes; most (20) had flattening of the articular eminence. Changes in condylar shape, erosions and cysts of the mandibular condyle and condylar head resorption were more frequent in the RA group than the control group (Table I). A statistically significant difference was only found for erosions and cysts of the mandibular condyle (Table I). Osteophytic changes were more frequent in
Figure 2. Four stages of bone changes of the mandibular condyle on CT in RA. e, erosion; c, cysts; s, sclerosis.
956
Figure 3. Extensive erosion of the condylar surface of the mandibular condyle in RA.
the RA group than in the control group, without a statistically significant difference (Table I). Erosions and bone cysts were demonstrated in 88% of the TMJ in RA compared with 58% in the control group (p < 0.05). In most cases, the bone changes in RA were bilateral.
Figure 4. Bony changes of the glenoid fossa on CT in RA. E, erosions; CT, glenoid fossa; CM, mandibular condyle.
The British Journal of Radiology, November 1992
CT of the temporomandibular joint in RA
Figure 5. Osteophyte arising from the glenoid fossa in RA.
Bone changes of the mandibular condyle among the RA group were classified into four grades (Fig. 2): Grade 1: erosions of the subchondral bone. Grade 2: erosions with deep cysts. Grade 3: extensive erosion of the condylar surface (Fig. 3). Grade 4: flattening and resorption of the condylar surface.
Figure 6. Meniscus calcification in RA (arrow).
Bone changes of the glenoid fossa were less frequent (Table I). Erosions and cysts involved either the floor or the internal part of the glenoid fossa (Fig. 4).
Table I. Bone changes among 26 patients with RA and 26 control subjects on coronal CT of the TMJ RA (n = 26)
Control (« = 26) Right TMJ
Left TMJ
Right TMJ
Left TMJ
19
17
20
17
-p < 0.001Erosions of the mandibular condyle -p< 0.001p < 0.001Cysts of the mandibular condyle
7 -p < O'.OOl -
Condylar head resorption Deformity of the mandibular condyle Osteophytes arising from mandibular condyle Erosions of the glenoid fossa Cysts of the glenoid fossa Flattening of the articular eminence Meniscus calcification Decreased joint space
Vol. 65, No. 779
5 11 5
4 12 3
10 17 6
11 20 7
6 5 19 4 13
6 4 18 1 13
9 7 14 4 12
9 10 16 1 9
957
P. Goupille, B. Fouquet, P. Cotty, D. Coga and J.-P. Valat
Figure 7. Calcification adjacent to the lateral aspect of the mandibular condyle in RA (arrow).
Figure 8. Medial osteophyte of the mandibular condyle in a "teardrop" configuration in RA (arrow).
Six patients with RA had large destructive lesions: (a) flattening of the mandibular condyle and glenoid fossa with erosions of the articular surfaces, sclerosis and decreased joint space; (b) multiple cysts of the articular surfaces, erosions, more decreased joint space and changes of the glenoid fossa; (c) osteophyte arising from the glenoid fossa (Fig. 5); and (d) an osteocartilaginous loose body was noted in one case. Intra-articular calcification was also seen: meniscal calcification in six cases (Fig. 6); larger intra-articular calcification in one case; and calcification along the outer part of the mandibular condyle in one case (Fig. 7). Ankylosis of the TMJ in RA was observed in two TMJs. Other changes (one in each case) were noted: (a) decreased joint space and sclerosis of the articular surfaces; (b) "teardrop" osteophyte of the mandibular condyle (Fig. 8); (c) osseous bridging between the glenoid fossa and the mandibular condyle; and (d) bone sequestra within an area of bone sclerosis (Fig. 9).
and the meniscal position (Helms et al, 1984a; Manzione et al, 1984; Sartoris et al, 1984; Thompson et al, 1984). The sagittal view may give more information regarding the position of the meniscus than the coronal view (Helms et al, 1984b; Manzione et al, 1984a; Manco et al, 1985; Raustia et al, 1985), but the coronal plane allows better visualization of the osseous elements of the TMJ (Horowitz et al, 1982; Larheim & Kolbenstvedt, 1984; Reck & Fielding, 1986). Axial sections cut the articular surfaces of the condylar head and glenoid fossa tangentially, precluding the demonstration of fine bone changes (Avrahami et al, 1989). The aim of our study was to estimate the osseous involvement of TMJ in RA, so the coronal plane was used. Erosions and cysts of the TMJ in RA on coronal CT were frequent in our study (88%). The only previous coronal CT study of the TMJ in adult RA found 68% of bone lesions of various degrees, but without a control group (Avrahami et al, 1989). Contrary to some other studies obtained with conventional radiography or tomography (Mayne & Hatch, 1969; Blair, 1973; Trenwith & Beale, 1977; Syrjanen, 1985), some bone changes were equally distributed in the two groups in our study, namely flattening of the
Discussion
Since Suarez et al (1980) made their preliminary study on CT of the TMJ, the technique has rapidly proved to be highly accurate for evaluating both bony changes 958
The British Journal of Radiology, November 1992
CT of the temporomandibular joint in RA high resolution computed tomography of the temporomandibular joints in patients with rheumatoid arthritis. Journal of Rheumatology, 16, 298-301. BLANC, P., 1959. L'atteinte de l'articulation temporo-maxillaire au cours du rhumatisme inflamatoire chronique. Cahiers Odonto-stomatologiques, 9, 17-73. CHALMERS, I. M. & BLAIR, G. S., 1973. Rheumatoid arthritis of
the temporomandibular joint. A clinical and radiological study using circular tomography. Quarterly Journal of Medicine (New series), 42, 369-386. ERICSON, S. & LUNDBERG, M., 1967. Alterations in the TMJ at
various stages of rheumatoid arthritis. Acta Rheumatologica Scandinavica, 13, 257-274. FRIEZ, L. & LE GOC, Y., 1982. Articulations temporomaxillaires et polyarthrite rhumatoi'de. Rhumatologie, 34, 193-196. HELMS, C. A., VOGLER, J. B. & MORRISH, R. B., 1984a.
Diagnosis by computed tomography of temporomandibular joint meniscus displacement. Journal of Prosthetic Dentistry, 51, 544-547. HELMS, C. A., VOGLER, J. B., MORRISH, R. B., GOLDMAN,
S. M., CAPRA, R. E. & PROCTOR, E., 1984b. Temporo-
mandibular joint internal derangements: CT diagnosis. Radiology, 152, 459-462. HOROWITZ,
I.,
AVRAHAMI,
E.
&
MINTZ,
S.
S.,
1982.
Demonstration of condylar fractures of the mandible by computed tomography. Oral Surgery, Oral Medicine, Oral Pathology, 54, 263-268. LARHEIM, T. A. & KOLBENSVEDT, A., 1984. High-resolution
computed tomography of the osseous temporomandibular joint. Some normal and abnormal appearances. Acta Radiologica, 25, 465^69. LARHEIM, T. A. & KOLBENSTVED, A., 1990. Osseous temporo-
Figure 9. Bone sequestrum (arrow) within a sclerotic area of the mandibular condyle in RA.
articular eminence, decreased joint space, calcification of the articular disc, osteophytosis and subchondral sclerosis. Erosions and changes in the shape of the mandibular condyle have been described as osteoarthritic lesions (Toller, 1973, 1974; Rasmussen, 1981). We found that the lesions most suggestive of RA were erosions and cysts of the mandibular condyle, and this agrees with some previous papers (Blanc, 1959; Mayne & Hatch, 1969; Chalmers & Blair, 1973). Bilateral involvement of the TMJ was more common in the RA group than in the control group, and this also agrees with previous papers (Resnick, 1974; Lowry, 1975; Seymour et al, 1975). In conclusion, coronal CT scanning is an accurate technique for evaluating bone changes in the TMJ. Erosions and cysts of the mandibular condyle and the bilateral nature of these abnormalities are suggestive of RA. Acknowledgment We wish to thank Mrs S. Gardes for typing the manuscript. References AVRAHAMI, E., SEGAL, R., SOLOMON, A., GARTI, A., HOROWITZ, I., CASPI, D., WIGLER, I. & YARON, M., 1989. Direct coronal
Vol. 65, No. 779
mandibular joint abnormalities in rheumatic disease. Computed tomography versus hypocycloidal tomography. Acta Radiologica, 31, 383-387. LARHEIM, T. A., STORHAUG, K. & TVEITO, L., 1983. Temporo-
mandibular joint involvement and dental occlusion in a group of adults with rheumatoid arthritis. Acta Odontologica Scandinavica, 41, 301-309. LOWRY, J. C , 1975. Psoriatic arthritis involving the temporomandibular joint. Journal of Oral Surgery, 33, 206-208. MANCO, L. G., MESSING, S. G., BUSINO, L. J., FASULO, C. P. &
SORDILL, W. C , 1985. Internal derangements of the temporomandibular joint evaluated with direct sagittal CT: a prospective study. Radiology, 157, 407-412. MANZIONE, J. V., KATZBERG, R. W., BRODSKY, G. L., SELTZER,
S. E. & MELLINS, H. Z., 1984. Internal derangement of the temporomandibular joint: diagnosis by direct sagittal computed tomography. Radiology, 150, 111-115. MAYNE, J. G. & HATCH, G. S., 1969. Arthritis of the temporo-
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