Biomedical subjects
Publications and source records attributed to Yukinori Takagi.
OBJECTIVE: A balanced turbo field-echo (FE) sequence is a balanced steady-state free precession sequence used for achieving rapid and high imaging. We tested whether this imaging technique is applicable to the diagnosis of parotid gland diseases. CONCLUSION: The balanced turbo FE sequence is a novel alternative MRI technique for the diagnosis of various parotid gland diseases.
PURPOSE: To establish a fast and high-resolution MR sialographic technique that provides fast and high-resolution imaging. MATERIALS AND METHODS: MR sialography was performed on a 1.5-T MR imager using a small (47-mm) surface coil. We determined appropriate sequence parameters, and then applied the technique to the salivary glands of 143 patients with xerostomia (including those with Sjögren's syndrome or hyperlipidemia) or salivary gland inflammation. We compared the high-resolution MR sialography with conventional x-ray sialography in the patients with xerostomia to evaluate the effectiveness of the MR sialography technique. RESULTS: We found that a single-shot, single-slice MR sialography (TR/TR/number of signal acquisitions [NSA] = 8000 msec/1000 msec/6) using a small surface coil provides excellent duct images that are clinically feasible with fast (imaging time of 56 seconds) and high-resolution images. An alternative three-dimensional MR sialography technique provided better details of the branches at the expense of imaging time. The MR sialography technique using a small surface coil depicted effectively the ductal changes in the salivary glands in patients with or without Sjögren's syndrome, reflecting the severity of the diseases. CONCLUSION: We conclude that MR sialography can be performed using a fast and high-resolution sequence.
OBJECTIVE: The purpose of this study was to detect quantitative diffusion-weighted abnormalities in the lacrimal glands of patients with Sjogren's syndrome. MATERIALS AND METHODS: Diffusion-weighted MRI was performed on 31 healthy volunteers and 11 Sjogren's syndrome patients with impaired lacrimal function. The volunteers and patients underwent MRI with a single-shot spin-echo echo-planar technique using a 47-mm microscopy coil. The apparent diffusion coefficient (ADC) of the lacrimal and parotid glands was obtained with b factors of 500 and 1,000 sec/mm(2). T1-weighted and fat-suppressed T2-weighted MR microscopic images were also obtained to evaluate the gland morphology and signals. RESULTS: MR microscopy provided high-resolution images of the lacrimal glands that enabled ADC measurements. The ADCs of the normal lacrimal glands showed no significant sex- or age-related changes. The ADCs for the lacrimal glands were significantly higher than those of the parotid glands in the same subjects (mean +/- SD, 891 +/- 103 vs 703 +/- 84 x 10(-6) mm(2)/sec, respectively; p < 0.0001, Mann-Whitney U test). We found that ADCs of the lacrimal glands in Sjogren's syndrome patients were significantly lower than those from the normal glands of age-matched healthy volunteers (736 +/- 34 vs 923 +/- 84 x 10(-6) mm(2)/sec; p < 0.0001, Mann-Whitney U test). CONCLUSION: These findings suggest that the measurement of ADCs may be a useful tool to assess abnormalities of the lacrimal glands in patients with Sjogren's syndrome.
BACKGROUND AND PURPOSE: MR imaging of the salivary glands has been applied to the diagnosis of Sjogren's syndrome; however, the diagnosis remains qualitative. We sought to establish and evaluate quantitative MR imaging criteria for the diagnosis of Sjogren's syndrome. METHODS: MR imaging with a 47-mm microscopy coil was performed in 83 patients with xerostomia (55 patients with Sjogren's syndrome, 28 without Sjogren's syndrome). MR images were obtained by T1-weighted and fat-suppressed T2-weighted imaging and by MR sialography of the parotid glands. MR imaging findings of the parotid glands in Sjogren's syndome included increases in fat areas and decreases in intact lobule areas. These MR images were morphometrically analyzed for the diagnostic criteria. RESULTS: MR imaging with a microscopy coil demonstrated well the details of the damaged parotid glands in patients with xerostomia. Quantitative MR imaging of fat, intact gland lobule, and number of sialoectatic foci significantly and highly correlated with severity of disease. Receiver operating characteristic (ROC) curve analysis demonstrated that quantitative MR imaging yielded high diagnostic ability in differentiating patients with xerostomia who have Sjogren's syndrome from those without Sjogren's syndrome, with areas under the ROC curve of 0.94 for fat area, 0.98 for intact lobule area, and 0.91 for number of sialoectatic foci. The best cutoff points by quantitative MR imaging were each associated with high sensitivity and specificity, and, when used in combination, yielded 96% sensitivity and 100% specificity. CONCLUSION: Quantitative MR imaging effectively differentiated the parotid glands in patients with xerostomia who have Sjogren's syndrome from those without the syndrome and provided criteria for staging the gland disease.
OBJECTIVE: We determined the apparent diffusion coefficients of normal and dysfunctional salivary glands. SUBJECTS AND METHODS: A diffusion-weighted single-shot spin-echo type of echoplanar MR imaging was performed on the parotid or submandibular glands, or both, in 36 healthy subjects, 20 patients with Sjögren's syndrome, and six patients with sialoadenitis. The apparent diffusion coefficient of the salivary gland was calculated using two b factors (b = 500 and 1,000 sec/mm(2)). RESULTS: The apparent diffusion coefficient was lower in the parotid glands (0.28 x 10(-3) mm(2)/sec) than that of the submandibular glands (0.37 x 10(-3) mm(2)/sec). The apparent diffusion coefficient was increased in sialoadenitis, whereas it decreased with abscess formation. The apparent diffusion coefficients of the parotid glands in patients with Sjögren's syndrome correlated with the salivary flow rates but not with the sialographic gradings of the glands. We also found a correlation of the decreases in apparent diffusion coefficients with the severity of gland damage as assessed on T1-weighted MR images. CONCLUSION: Diffusion-weighted echoplanar MR imaging may reveal diseased states of the salivary glands.