Ikuko Nishida

Dynamic magnetic resonance sialography for patients with xerostomia.

OBJECTIVE The aim was to evaluate the utility of dynamic magnetic resonance (MR) sialographic images as a diagnostic tool for patients with xerostomia as chief complaint. METHODS Various parameters of dynamic MR sialographic images from 40 healthy volunteers were compared with those from 28 patients having dry mouth as chief complaint. Dynamic MR sialographic images were acquired using a 1.5-T full-body MR system and 2-dimensional fast asymmetric spin-echo (2D-FASE) sequences. Acquisition of the optimal section using 2D-FASE sequencing with single-section acquisition of thick sections was repeated every 30 s before and after a few drops of 5% citric acid was placed on the tongue. Student t test was used to examine differences between the healthy volunteer and patient groups regarding the maximum area of salivary gland ducts before and after citric acid stimulation. RESULTS The maximum area of the detectable ducts in the patient group was significantly smaller (P < 0.001), whereas the change in detectable duct area was significantly lower (P < 0.001). CONCLUSIONS This study suggests that dynamic MR sialographic images and data can be useful in the diagnosis of patients with dry mouth as chief complaint.

A spatial association between odontomas and the gubernaculum tracts

OBJECTIVES The purpose of this study was to identify the spatial relationship and/or association between odontomas and the gubernaculum tract or the dental sac and the characteristic findings for radiographic diagnosis of odontomas. STUDY DESIGN The visualizations of the odontomas and the gubernaculum tract were retrospectively analyzed using cone beam computed tomography or multidetector computed tomography. RESULTS Most of odontomas were within the gubernaculum tract or dental sac of unerupted permanent teeth on computed tomography. In some odontomas, the gubernaculum tract existed as a well-defined low density tract extending from the top of odontomas on computed tomography. CONCLUSIONS A close spatial relationship and/or association between odontomas and the gubernaculum tract or dental sac on computed tomography may be used as one of the criteria for radiographic diagnosis of odontomas. Development of odontomas may be associated with the gubernaculum tract or dental sac of unerupted permanent teeth.

Detection and imaging characteristics of the gubernacular tract in children on cone beam and multidetector computed tomography

PURPOSE To elucidate the appearance and imaging characteristics of the gubernacular tract (GT) during the growth stage of children. Furthermore, this study evaluated the significance of the appearance of the GT. STUDY DESIGN The visualizations of the GT were retrospectively analyzed by using panoramic radiographs and computed tomography (CT) in children. RESULTS In patients with normal eruption who had unerupted permanent teeth, except maxillary central supernumerary teeth, the GT was clearly visualized as a well-defined low-density tract on CT but not on panoramic radiographs. In patients with obstructive eruption, including impaction, the GT was deformed and not visible on CT. CONCLUSIONS This paper describes the frequency of detection and appearance of the GT in unerupted teeth. Preliminary data suggest that any alteration to the GT may be used to predict abnormal eruption of permanent teeth.

Characteristics of the gubernaculum tracts in mesiodens and maxillary anterior teeth with delayed eruption on MDCT and CBCT

OBJECTIVES To elucidate the characteristics of the gubernaculum tracts (GTs) in maxillary anterior teeth with normal or delayed eruption and in mesiodens by using multidetector computed tomography and cone beam computed tomography. STUDY DESIGN The characteristics of GTs in maxillary anterior teeth of 205 patients with impacted mesiodens were retrospectively analyzed by using multidetector computed tomography and cone beam computed tomography. The GTs of teeth with normal or delayed eruption and the GTs of mesiodens were examined. RESULTS The detection ratio of GTs in impacted mesiodens and anterior teeth with delayed eruption was significantly lower than in teeth with normal eruption. A significant difference in the angulation was found between normal and delayed eruptions. Almost all detectable GTs in the inverted mesiodens were derived from the incisive canal, while the remaining were from the alveolar crest. The connecting area of major GTs to tooth in inverted mesiodens was the cervical or root area, but in all other anterior teeth, it was the crown area. CONCLUSIONS GTs of inverted mesiodens may exhibit characteristics that are different from those of normal GTs when the teeth and/or the palate are developing.

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.

Characteristics of diffusion-weighted images and apparent diffusion coefficients of ranulas and other masses in and around the floor of the mouth

OBJECTIVE The aim of this study was to evaluate the characteristics of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values of ranulas. In addition, to elucidate DWI findings and ADC values of other representative masses in and around the floor of the mouth. STUDY DESIGN DWI findings and ADC values in 35 patients with ranulas and 33 patients with other masses were retrospectively reviewed with a central focus on cystic masses or lesions that may have cyst-like components in and around the floor of the mouth based on the diagnosis of each respective disease. RESULTS Ranulas were all well-defined, homogeneous masses with high signal intensity on DWI. The mean ± standard deviation ADC value of the 35 ranulas was 2.59 ± 0.31 × 10-3 mm2/s. There was a significant difference in ADC values between simple and plunging ranulas. On DWI, most other masses were heterogeneous, and most ADC values, except those for thyroglossal duct cysts, hemangiomas, and pleomorphic adenomas, were significantly lower than those for ranulas. CONCLUSIONS The characteristic DWI and ADC findings of ranulas can be determined accurately, and these data can be significantly useful in the differential diagnosis of many kinds of diseases in and around the oral floor.

Magnetic Resonance Angiography Using Fresh Blood Imaging in Oral and Maxillofacial Regions

The present paper provides general dentists with an introduction to the clinical applications and significance of magnetic resonance angiography (MRA) in the oral and maxillofacial regions. Specifically, the method and characteristics of MRA are first explained using the relevant MR sequences. Next, clinical applications to the oral and maxillofacial regions, such as identification of hemangiomas and surrounding vessels by MRA, are discussed. Moreover, the clinical significance of MRA for other regions is presented to elucidate future clinical applications of MRA in the oral and maxillofacial regions.

Alterations of the Temporomandibular Joint on Magnetic Resonance Imaging according to Growth and Development in Schoolchildren

The paper explains the alterations of the temporomandibular joint (TMJ) visualized by magnetic resonance imaging (MRI) according to the growth and development of schoolchildren. Appearance and disappearance of a “double contour-like structure” (DCLS) of the mandibular condyle on MRI according to the growth and development of schoolchildren were demonstrated. In addition, possible constituents of DCLS and the significance of detection of DCLS on MRI were also speculated. The relationship between red marrow and yellow marrow in the articular eminence of temporal bone, the disappearance of DCLS, and alterations of the mandibular condyle have been elucidated.

Importance of magnetic resonance imaging for evaluation of a child with prominent swelling of the facial region after trauma: report of a case

In the present case of a 9-year-old girl with prominent swelling in the mental and facial regions after trauma, repeated magnetic resonance (MR) examinations were performed to evaluate areas of incision, because the swelling became worse and more prominent despite intravenous antibiotic treatment. However, there was no evidence of respiratory tract impingement or deformation, including obliteration, on MR imaging. Therefore, surgical treatment involving an incision because of facial region swelling was cancelled, and the intravenous antibiotic therapy was continued. To prevent misdiagnosis and over-treatment of young children with inflammation of the oral and maxillofacial regions, dentists, including pediatric dentists, should be aware of the clinical usefulness of MR examinations. In particular, MR examinations are non-invasive for young children, because there is no X-ray exposure, and they can be used repetitively. At the same time, the present case demonstrated that it is very difficult to understand and predict changes in the inflammation process associated with childrens facial trauma.

Effect of the combination of ipriflavone and 1α-OH-D3 on debilitant bone in growing rats —Ultrastructural study of endochondral ossification—

Abstract Five-week-old male Wistar rats were used to study the effect of dietary therapy with ipriflavone combined with 1α-OH-D 3 . Ultrastructural alterations in the metaphysis of debilitated tibia were observed in the growing rats. I.Light microscopy findings In the low-calcium diet • standard diet with supplementary ipriflavone and 1α-OH-D 3 group, calcification of the chondral matrix and ossification were active, and the tibia grew normally as in the control group. II.Scanning electron microscopy findings In the low-calcium diet • standard diet with supplementary ipriflavone and 1α-OH-D 3 group, dense calcospherites, distinct chondral lacunae, regularly running collagen fibers, and distinct border lines were noted. III.Transmission electron microscopy findings In the low-calcium diet • standard diet with supplementary ipriflavone and 1α-OH-D 3 group we found that the osteoblasts were active, the ruffled border of osteoclast was decrease, indicated this osteoclast is inactive. In conclusion, insufficient calcium intake during the developmental period resulted in debilitated(3etaphysis tibia, whereas dietary therapy using combined ipriflavone and 1α-OH-D3 promoted recovery.