MR Microscopy of the Parotid Glands in Patients with Sjögren’s Syndrome: Quantitative MR Diagnostic Criteria
Yukinori Takagia,
Misa Sumia,
Tadateru Sumia,
Yoko Ichikawaa and
Takashi Nakamuraa
a From the Department of Radiology and Cancer Biology, Nagasaki University School of Dentistry, Nagasaki, Japan
View larger version (63K):
[in a new window]
|
FIG 1. Quantitative MR imaging.
A, Photograph of the 47-mm microscopy coil used for T1-weighted and fat-suppressed T2-weighted (SPIR) imaging, as well as for MR sialography.
B and C, MR images (left) were converted to binary data (right). Fat areas (on T1-weighted images) and intact lobule areas (on fat-suppressed T2-weighted images) were calculated as percentages of the maximal cross-sectional areas of the same glands on T1-weighted image (B). On the MR sialogram (C), the numbers and areas of the sialoectatic high-intensity signals were enumerated.
| |
View larger version (132K):
[in a new window]
|
FIG 2. Characteristic MR imaging features of the parotid glands.
A–C, Axial T1-weighted images of parotid glands from a xerostomia patient without Sjögren’s syndrome (A), from a xerostomia patient with Sjögren’s syndrome (B), and from a patient with parotitis (C).
D–F, Axial fat-suppressed T2-weighted images of parotid glands from the xerostomia patient without Sjögren’s syndrome (D), from the xerostomia patient with Sjögren’s syndrome (E), and from the patient with parotitis (F), same patients as shown in A–C, respectively. Note the high-signal-intensity cores in the gland of the patient with Sjögren’s syndrome (E), suggestive of lymphocyte aggregations in the gland. This may be a characteristic feature of the glands affected by this disease.
| |
View larger version (85K):
[in a new window]
|
FIG 3. MR imaging features of the parotid glands relative to conventional sialographic grades in xerostomia patients with or without Sjögren’s syndrome.
A–E, Axial T1-weighted MR images of the parotid glands in patients whose conventional sialographs were categorized as grade 0 (A), grade 1 (B), grade 2 (C), grade 3 (D), or grade 4 (E). Note that fat areas in the glands increase with the grades.
F–J, Axial fat-suppressed T2-weighted MR images of the parotid glands in patients (same patients as in A–E, respectively) whose conventional sialographs were categorized as grade 0 (F), grade 1 (G), grade 2 (H), grade 3 (I), or grade 4 (J). Note that intact lobule areas in the glands decrease with the grades.
| |
View larger version (16K):
[in a new window]
|
FIG 4. T1-weighted and fat-suppressed T2-weighted MR imaging features of the parotid glands correlated well with conventional sialographic features. The horizontal bar indicates mean; small circles, outliers.
A, Graph shows a high correlation between fat areas as assessed on T1-weighted MR images and conventional sialographic grades (G0–G4).
B, Graph shows a high correlation between intact lobule area as assessed on fat-suppressed T2-weighted MR images and conventional sialographic grades (G0–G4).
| |
View larger version (35K):
[in a new window]
|
FIG 5. A–C, Sagittal MR sialography of parotid glands from a xerostomia patient without Sjögren’s syndrome (A), a xerostomia patient with Sjögren’s syndrome (B), and a patient with parotitis (C).
| |
View larger version (61K):
[in a new window]
|
FIG 6. Discrepancy in imaging features of the parotid glands between MR sialography and conventional sialography.
A–J, MR sialograms (A–E) and conventional sialograms (F–J) of the parotid glands in xerostomia patients with or without Sjögren’s syndrome: grade 0 (A and F), grade 1 (B and G), grade 2 (C and H), grade 3 (D and I), and grade 4 (E and J). Note apparent differences in sialographic features at grade 4 (E versus J).
| |
View larger version (14K):
[in a new window]
|
FIG 7. MR sialographic features are not correlative to conventional sialographic features in the end stages of the disease. The horizontal bar indicates mean; small circles, outliers.
A and B, Graphs show the relationship between the number of sialoectatic foci (A) and the size of sialoectatic foci (B) on MR sialograms and the grades (G0–G4) with conventional sialography. Note the poor correlations between these two sialographic features at grades 3 and 4. NS indicates not significant.
| |
View larger version (22K):
[in a new window]
|
FIG 8. Graph shows averaged ROC curves for MR imaging criteria for differentiating xerostomia patients with Sjögren’s syndrome from those without Sjögren’s syndrome, by using fat area on T1-weighted images, intact lobule area on fat-suppressed T2-weighted images, and the number and size of sialoectatic foci on MR sialograms. The Az values calculated from ROC curves, which indicate the diagnostic ability using these criteria, are as follows: Az (fat area) = 0.94 ± 0.03, Az (lobule area) = 0.98 ± 0.02, Az (number) = 0.91 ± 0.04, and Az (size) = 0.89 ± 0.04.
| |
AJNR - American Journal of Neuroradiology