Changes in tonsillolith characteristics detected in a follow-up CT study.

BACKGROUND: Tonsilloliths are related clinically to halitosis and tonsillar abscess. However, the dynamics of tonsilloliths over time are unknown. The aim of the study was to evaluate change in the characteristics of tonsilloliths in a time-dependent fashion by follow-up computed tomography (CT). METHODS: Tonsilloliths were analyzed in 326 CT scan pair sets of initial and at least two follow-up CT examinations of patients with whole palatine tonsils and various diseases of the oral and maxillofacial regions. RESULTS: Over the follow-up period, 12.1% of tonsilloliths disappeared. Approximately 26.1% of tonsilloliths changed in size during follow-up, mostly increasing in size. In tonsilloliths that showed enlargement, the mean (± standard deviation) growth rate was 0.61 ± 0.41 mm per year. Approximately 37.3% of tonsilloliths changed position during the follow-up period; of these, movement was toward the respiratory tract in 92% at a mean rate of - 1.38 ± 1.59 mm per year. The calcification levels of almost all tonsilloliths showed dynamic change: HU number increased in 84.3% and decreased in 12.7% of tonsilloliths over the follow-up period. The mean rate of HU increase was 63.8 ± 96.3 HU/year, and the mean rate of HU decrease was - 38.4 ± 66.8 HU/year. CONCLUSIONS: The calcification levels of all tonsilloliths showed dynamic fluctuation, and a tendency for excretion of tonsilloliths from the body. Their dynamics over time suggest that tonsilloliths may be in a permanently active phase which functions to remove foreign matter.

Can the lower rate of CT- or MRI-related adverse drug reactions to contrast media due to stricter limitations on patients undergoing contrast-enhanced CT or MRI?

OBJECTIVE: The aim of this study was to examine whether a decreased occurrence rate of adverse drug reactions (ADRs) to contrast media in contrast-enhanced CT and MRI was attributable to appropriate criteria for patients with some diseases. A secondary aim was to elucidate safety profiles for contrast media and factors influencing the occurrence of ADRs. METHODS: Clinical data of patients who underwent contrast-enhanced CT (5576 cases) or MRI (3357 cases) were retrospectively analyzed to evaluate rates of ADRs to contrast media, symptoms of ADRs, treatments for ADRs, and differences in medical history, blood test results, and other factors between patients with and without ADRs in a dental hospital. RESULTS: The rate of ADRs to contrast media was 0.54% for CT and 0.09% for MRI. The most frequent ADRs in contrast-enhanced CT or MRI were nausea and vomiting as physiologic reactions. Two serious reactions were seen for CT, but none for MRI. Significant differences between patients with and without ADRs were seen in liver function according to blood tests for CT, and in digestive disorders elicited from medical interviews for MRI. CONCLUSION: The lower occurrence rate of ADRs to contrast media in dental hospitals could be due to the adoption of appropriate criteria for patients with some diseases undergoing enhanced CT or MRI. Complete suppression of ADRs to contrast media for CT or MRI is unrealistic, so attention is warranted for patients with decreased liver function when performing enhanced CT, and for patients with digestive disorders when performing enhanced MRI.

First Report of Sublingual Gland Ducts: Visualization by Dynamic MR Sialography and Its Clinical Application.

This study was done to determine whether the sublingual gland ducts could be visualized and/or their function assessed by MR sialography and dynamic MR sialography and to elucidate the clinical significance of the visualization and/or evaluation of the function of sublingual gland ducts by clinical application of these techniques. In 20 adult volunteers, 19 elderly volunteers, and 7 patients with sublingual gland disease, morphological and functional evaluations were done by MR sialography and dynamic MR sialography. Next, four parameters, including the time-dependent changes (change ratio) in the maximum area of the detectable sublingual gland ducts in dynamic MR sialographic images and data were analyzed. Sublingual gland ducts could be accurately visualized in 16 adult volunteers, 12 elderly volunteers, and 5 patients. No significant differences in the four parameters in detectable duct areas of sublingual glands were found among the three groups. In one patient with a ranula, the lesion could be correctly diagnosed as a ranula by MR sialography because the mass was clearly derived from sublingual gland ducts. This is the first report of successful visualization of sublingual gland ducts. In addition, the present study suggests that MR sialography can be more useful in the diagnosis of patients with lesions of sublingual gland ducts.

Real-time evaluation of swallowing in patients with oral cancers by using cine-magnetic resonance imaging based on T2-weighted sequences.

OBJECTIVE: The aim of this study was to evaluate whether a new cine-magnetic resonance imaging (CMRI) technique might be useful for evaluating swallowing function in patients with different types of oral cancers by assessing 12 CMRI-related parameters. STUDY DESIGN: In total, 111 patients with oral cancers were evaluated. We examined whether visualization of fluid flow and determination of flow direction to the trachea or the esophagus were possible with CMRI. We evaluated the correlations between CMRI-related parameters and self-reported dysphagia scores as the status of dysphagia, T classification groups as tumor staging for preoperative patients, alterations in CMRI-related parameters between pre- and postoperative patients, and the degree of invasiveness of oral cancer surgery. RESULTS: We could judge the flow direction to the esophagus on CMRI in all 111 patients. Six CMRI-related parameters showed significant correlations with dysphagia status. Increases in CMRI-related parameters were significantly related to deterioration of swallowing status, as shown by a decrease in self-reported dysphagia scores, advances in the T classification, and degree of invasiveness of oral cancer surgery. CONCLUSIONS: The results of the present study suggest that CMRI can be used to directly visualize swallowing dynamics and objectively evaluate the swallowing complaints of patients with oral cancer.

Significance and usefulness of imaging characteristics of gubernaculum tracts for the diagnosis of odontogenic tumors or cysts.

We aimed to determine the significance and usefulness of imaging characteristics of gubernaculum tracts (GT) for the diagnosis of odontogenic tumors or cysts. This was a retrospective analysis of relationships between odontogenic or non-odontogenic tumors or cysts and the GT that were visualized using multi-detector computed tomography (MDCT). The relationship between the size of a mass and expansion of the GT in all odontogenic tumors or cysts to which GTs were contiguous on MDCT, was statistically analyzed. Intact or expanded GTs were detected in MDCT images on the top of almost all odontogenic tumors or cysts, but not on non-odontogenic tumors or cysts. Characteristic image findings regarding the relationship between the GT and the odontogenic mass were detected for the respective odontogenic tumors or cysts in which the GTs were contiguous to the mass on MDCT. In ameloblastomas, expansion of the GTs significantly and very strongly correlated with tumor size (r = 0.741, p = 0.0001), but this correlation was very weak in dentigerous cysts (r = 0.167, p = 0.028) and there was no correlation between these parameters in odontogenic keratocysts (r = -0.089, p = 0.557). The imaging characteristics of GTs at the top of masses should be very useful for both the differential diagnosis of the pathological diagnosis of odontogenic masses and for differentiation between odontogenic and non-odontogenic masses.

Functional evaluation of swallowing in patients with tongue cancer before and after surgery using high-speed continuous magnetic resonance imaging based on T2-weighted sequences.

OBJECTIVES: The aim of this study was to determine the usefulness of evaluating the function of swallowing before and after surgery in patients with tongue cancer by using T2-weighted sequences of high-speed continuous magnetic resonance imaging (HSCMRI). STUDY DESIGN: The imaging findings and related parameters on HSCMRI along with those on routine MRI examinations before and after surgery were examined in 19 patients with tongue cancer. In addition, changes in various parameters during 1 year after surgery were evaluated in 10 patients. RESULTS: In most patients examined, the direction of flow to the esophagus could be seen on HSCMRI before and after surgery. Significant correlations were observed among 4 parameters and in the responses to a dysphagia questionnaire. CONCLUSIONS: The results of the present study suggest that the dynamics of swallowing can be directly visualized on HSCMRI by using 4 parameters that permit the evaluation of changes before and after surgery, and this enables objective evaluation of patients' swallowing complaints.

Changes in the distributions of fluorine-18-labelled fluoro-2-deoxy-d-glucose accumulation into tongue-related muscles after dissection in patients with tongue cancer.

OBJECTIVES: To elucidate the changes in the distributions of fluorine-18-labelled fluoro-2-deoxy-d-glucose (18F-FDG) accumulation in the tongue muscles of patients following four kinds of surgical operations for tongue cancers. METHODS: The changes in the distributions of 18F-FDG accumulations in the tongue muscles on positron emission tomography (PET)-CT, in association with imaging findings on CT and MRI, were retrospectively analyzed before and after four kinds of surgical operations for 50 patients with tongue cancers. RESULTS: 18F-FDG-PET-positive areas appeared at the back of the intrinsic muscles of the tongue after invasive surgery for tongue cancers despite the absence of abnormal findings on CT and MRI. A correlation between the standardized uptake value maximum of 18F-FDG in the intrinsic muscles and the degree of invasiveness of the surgical procedures for tongue cancers (r = 0.539, p < 0.01) was found. CONCLUSIONS: It is important to pay attention to the changes in 18F-FDG distributions in the intrinsic muscles of the tongue before and after invasive surgery despite the absence of abnormal findings on CT and MRI when evaluating the tongue on 18F-FDG-PET.

Expression of neuropeptide receptor mRNA during osteoblastic differentiation of mouse iPS cells.

Various studies have shown a relationship between nerves and bones. Recent evidence suggests that both sensory and sympathetic nerves affect bone metabolism; however, little is known about how neuropeptides are involved in the differentiation of pluripotent stem cells into osteoblastic (OB) cells. To evaluate the putative effects of neuropeptides during the differentiation of mouse induced pluripotent stem (iPS) cells into calcified tissue-forming OB cells, we investigated the expression patterns of neuropeptide receptors at each differentiation stage. Mouse iPS cells were seeded onto feeder cells and then transferred to low-attachment culture dishes to form embryoid bodies (EBs). EBs were cultured for 4 weeks in osteoblastic differentiation medium. The expression of α1-adrenergic receptor (AR), α2-AR, ß2-AR, neuropeptide Y1 receptor (NPY1-R), neuropeptide Y2 receptor (NPY2-R), calcitonin gene-related protein receptor (CGRP-R), and neurokinin 1-R (NK1-R) was assessed by reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR. Among these neuropeptide receptors, CGRP-R and ß2-AR were expressed at all stages of cell differentiation, including the iPS cell stage, with peak expression occurring at the early osteoblastic differentiation stage. Another sensory nervous system receptor, NK1-R, was expressed mainly in the late osteoblastic differentiation stage. Furthermore, CGRP-R mRNA showed an additional small peak corresponding to EBs cultured for 3 days, suggesting that EBs may be affected by serum CGRP. These data suggest that the sensory nervous system receptor CGRP-R and the sympathetic nervous system receptor ß2-AR may be involved in the differentiation of iPS cells into the osteoblastic lineage. It follows from these findings that CGRP and ß2-AR may regulate cell differentiation in the iPS and EB stages, and that each neuropeptide has an optimal period of influence during the differentiation process.