Article Figures & Data
Figures
- Fig 1.
A and B, Coronal scanning plane and ROI-based measurements of the TMJ synovia. An oblique coronal plane was prescribed off the sagittal localizer to include the entire right and left TMJs and the longus capitis in the same coronal FOV. The coronal plane was angled superoanterior to posteroinferior to include both the TMJs from anterior to posterior and the longus capitis muscle; in controls, the oblique coronal plane included both TMJs, the longus capitis, and the sella turcica. C, An example of a single ROI at the superomedial synovial edge of the right TMJ (0.5 mm2) on a precontrast MR imaging and a single ROI placed along the longus capitis muscle (50 mm2), which was used for normalization. D, Example of the 10 ROIs placed on a postgadolinium MR imaging. These ROIs are placed along the superior and inferior synovial compartments of the left TMJ with the following designations: SL indicates superior compartment, lateral edge; SML, superior compartment, midlateral edge; SC, superior compartment, central; SMM, superior compartment, midmedial edge; SM, superior compartment, medial edge; IL, inferior compartment, lateral edge; IML, inferior compartment, midlateral edge, IC, inferior compartment, central; IMM, inferior compartment, midmedial edge; IM, inferior compartment, medial edge. Although attempts were made to measure the signal along the area closest to the disk edge in the expected location of the synovium, these measurements undoubtedly reflect a composite of signal produced by the synovium, cartilage, and perhaps the periosteum. Thus, the notion of “synovial signal” used in this report reflects this currently unavoidable composite measurement.
- Fig 2.
A, Mean ER1 for the symptomatic JIA, asymptomatic JIA, and control joints. ER1 shows a monopeak profile with an upward slope that starts at 10 minutes 30 seconds at the end of run 8 and clear separation of the curves between 10 minutes 30 seconds and 13 minutes 10 seconds during runs 9 and 10. B, Individual patient profiles for ER1 for the symptomatic JIA joints. C, Individual patient profiles for ER1 for the asymptomatic JIA joints. D, Individual patient profiles for ER1 for the control TMJ joints. These joints exhibit relatively constant enhancement ratios between 0.73 and 5 at all time points. E, Mean ER2 for the symptomatic JIA, asymptomatic JIA, and control joints. Note the clear separation among the 3 groups at all sampling time points with the mean profile for the symptomatic JIA group showing a monopeak profile. Also, the mean profile of the asymptomatic JIA group is higher at all time points than the mean profile for the control group. F, Individual patient profiles for ER2 for symptomatic JIA joints. All but one of the symptomatic joints, patient 8 RT TMJ, pass above the threshold value of normal (0.95) at multiple time points that thus results in correct classification of 10/11 symptomatic joints. G, Individual patient profiles for ER2 for asymptomatic JIA joints. Most profiles stay below the threshold normal value (0.94) while several pass above. H, Individual patient profiles for ER2 for control TMJ joints. The initial ER2 at 1 minute 10 seconds ranges from 0.15 to 0.5, and the end ER2 for this group at 13 minutes 10 seconds ranges from 0.14 to 0.63. The maximum ratio (peak) reached by any single patient at any time point is 0.94 that serves as a threshold value for normal for ER2. I, Mean R for the symptomatic JIA, asymptomatic JIA, and control joints. Note the clear separation among the 3 groups at all sampling time points. The mean profile for the symptomatic JIA group shows a monopeak profile. J, Individual patient profiles for R for the symptomatic JIA joints. Two joints, patient 2 L TMJ and patient 8 R TMJ, never pass above the 1.55 threshold and thus would be misclassified by R as asymptomatic joints. A third joint, patient 8 L TMJ, passes above the threshold only twice that may result in an indeterminate or borderline classification. K, Individual patient profiles for R for the asymptomatic JIA joints. Two of these joints, patient 5 L TMJ and patient 7 L TMJ pass above the normal threshold. L, Individual patient profiles for R for the control TMJ joints. While most of these joints stay below the 1.55 threshold, one joint, patient 12 L TMJ passes above the threshold at 4 time points, that may lead to misclassification of this joint.
- Fig 3.
Raw T1 hyperintensity curves of the longus capitis muscle as measured on the precontrast image and each of the 10 postgadolinium dynamic images. The raw signal of the longus capitis is similar at all sampling time points in both the JIA and control groups: no statistically significant difference (P = .99) was seen at any time point, suggesting that the longus capitis may serve as a normalization standard for both normal and symptomatic groups.
Tables
Parameters Details Sequence Coronal T1 postgadolinium, 70-sec, 10-sec prescan TR/TE (ms) 400/15 Frequency × phase 300 × 200 NEX 1 Section thickness 3 mm, 0-mm gap FOV 14–16 cm Timing of the serial runs Runs: run 0, pregadolinium run, followed by 10 postgadolinium runs with the following timing intervals: run 1: 0 -1 min 10 sec, run 2: 1 min 20 sec to 2 min 30 sec; run 3: 2 min 40 sec to 3 min 50 sec; run 4: 4 min 00 sec to 5 min 10 sec; run 5: 5 min 20 sec to 6 min 30 sec; run 6: 6 min 40 sec to 7 min 50 sec; run 7: 8 min 00 sec to 9 min 10 sec; run 8: 9 min 20 sec to 10 min 30 sec; run 9: 10 min 40 sec to 11 min 50 sec; run 10: 12 min 00 sec to 13 min 10 sec Injection technique Standard supine position 22-ga angiocatheter in right antecubital fossa, attached to 20-cm length of standard tubing connected to a power injector Contrast agent and dosing Gadoterate meglumine (Dotarem)a maintained at room temperature was drawn up at a dose of 0.2 mL/kg (0.1 mmol/kg) of body weight Simultaneous with the start of the first coronal T1 dynamic sequence, run 1, gadoterate was administered by power injector as a single intravenous bolus injection at a flow rate of 2.5 mL/s followed by a 20-mL saline chaser at the same injection rate ↵a Guerbet, Aulnay-sous-Bois, France.
- Table 2:
Measurements of signal intensity over the synovium and longus capitis muscles and calculation of the normalized ratios ER1, ER2, and R
Calculations Synovial signal intensity Pre = (SL+SML+SC+SMM+SM+IL+IML+IC+IMM+IM)/10, where, Pre = average precontrast synovial T1 signal intensity measured at 10 points along the synovia Postn = (SL+SML+SC+SMM+SM+IL+IML+IC+IMM+IM)n /10, where, Postn = average postgadolinium synovial signal, for run n (n = 1–10) measured at 10 points along the synovia Synovial enhancementn = Postn–Pre, for each run n (n = 1–10) Longus capitis intensity LCPRE = precontrast T1 signal in the longus capitis LCPOSTn = postcontrast T1 signal in the longus capitis, for run n (n = 1–10) Longus capitis enhancementn = LCPOSTn–LCPRE, for each run n (n = 1–10) Normalized ratios ER1 = (postgadolinium T1 signal of the TMJ synovium − the pregadolinium T1 signal of the TMJ synovium) divided by the (postgadolinium T1 signal of the longus capitis − the pregadolinium T1 signal of the longus capitis) where ER1 thus represents the ratio of the synovial enhancementn to the longus capitis enhancementn for each run n ER2 = (postgadolinium T1 signal of the TMJ synovium − the pregadolinium T1 signal of the TMJ synovium) divided by the postgadolinium T1 signal of the longus capitis where ER2 thus represents the ratio of the synovial enhancementn to the LCPOSTn for each run n R = the postgadolinium T1 signal of the TMJ synovium divided by the postgadolinium T1 signal of the longus capitis and thus represents the ratio of Postn to LCPOSTn Note:—n indicates each run; SL, superior compartment, lateral edge; SML, superior compartment, midlateral edge; SC, superior compartment, central; SMM, superior compartment, midmedial edge; SM, superior compartment, medial edge; IL, inferior compartment, lateral edge; IML, inferior compartment, midlateral edge; IC, inferior compartment, central; IMM, inferior compartment, midmedial edge, IM, inferior compartment medial edge; LCPRE, the measurement of the T1 signal in the longus capitis muscle on the coronal pregadolinium T1 sequence; LCPOSTn, the measurement of the T1 signal in the longus capitis on the postgadolinium coronal T1 sequence for runs 1–10.
Jump to section
Related Articles
Cited By...
- No citing articles found.