Virtual endoscopic view of salivary gland ducts using MR sialography data from three dimension fast asymmetric spin-echo (3D-FASE) sequences: a preliminary study

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.

Planimetric correlation between the submandibular glands and the pancreas: a postmortem ductographic study

The salivary glands and pancreas have comparable anatomic and antigenic properties and can share common pathogenetic mechanisms involving toxic or autoimmune processes. The aim of this study is to assess the correlation in size between the normal submandibular glands and the pancreas. The study was based on human autopsy specimens of the pancreas, neck and oral base from 22 adults, both sexes (mean age, 57.9 years). The pancreatic and submandibular ducts were injected with a contrast medium, and the area of the salivary and pancreatic glandular ductograms was measured with the aid of software for quantification of visual information. Samples of tissue from the salivary glands and the pancreas were studied by means of light microscopy. A high correlation was found between the planimetric size of the pancreas and the submandibular glands (correlation coefficient 0.497 and 0.699 for the right and the left gland, respectively). This ratio was close to 5:1. There were no significant differences in size for the left vs. right submandibular gland (p = 0.39). The ductograms were significantly larger in size in males than in females (p < 0.001). This study has proven a positive correlation in planimetric size between the normal submandibular glands and pancreas, a result that is expected to have possible clinical implications in the long-term follow-up of patients with chronic pancreatitis.

Diffusion-weighted MRI findings in Sjögren's syndrome: a preliminary study

BACKGROUND

Parotid glands diffusion-weighted imaging (DWI) in Sjögren's syndrome patients have provided conflicting results currently.

PURPOSE

To determine if parotid gland DWI using a small region of interest (ROI) can provide diagnosis and assess therapeutic efficacy in Sjögren's syndrome.

MATERIAL AND METHODS

Twenty-three women with Sjögren's syndrome, five with dry mouth who did not meet diagnostic criteria for Sjögren's syndrome, and 11 healthy volunteers (controls) were evaluated with DWI. All participants received routine T1-weighted (T1W) imaging and T2-weighted (T2W) fat-suppressed imaging, and DWI. The SI ratios (SIRs) and ADC ratios (ADCRs) for parotid gland/spinal cord were then calculated. Approximately 8-10 round ROIs measuring approximately 5 mm(2) were placed on each lobe of the parotid gland, and the signal intensity (SI) was measured while avoiding fat, ducts, and blood vessels. A ROI encompassing the entire lobe of the parotid gland was also used to measure SI.

RESULTS

Using 5 mm(2) ROIs significantly higher DWI SIRs were noted in participants with Sjögren's syndrome compared with either participants with dry mouth without Sjögren's syndrome or healthy volunteers (all, P <0.001). The difference was not related to the presence of fat. No differences were noted when the larger ROI was used. In addition, parotid gland from untreated Sjögren's participants showed significantly higher SIRs compared with those from treated participants (P = 0.015).

CONCLUSION

A small ROI DWI can provide morphological and functional information on the parotid gland in Sjögren's syndrome patients, and can aid in the diagnosis and evaluation of therapeutic efficacy.

Significance of Frequency-Selective Fat Saturation T2-Weighted MR Images for the Detection of Bone Marrow Edema in the Mandibular Condyle

The objective of this study was to evaluate the utility of frequency-selective fat saturation (FS) T2-weighted images (T2WI) for the detection of bone marrow edema in the mandibular condyle. MR evidence of bone marrow abnormalities was examined on the set of FS T2WI and conventional T1WI or of conventional T2WI and T1WI in 200 patients with temporomandibular joint (TMJ) related pain. Other parameters studied were TMJ effusion, disk displacement categories, and cortical bone abnormalities. The detection rate and area of bone marrow edema by FS T2WI and T1WI were significantly greater than those assessed by conventional T2WI and T1WI. The correlation between bone marrow abnormalities on FS T2WI and T1WI and pain was significantly stronger than with conventional T2WI and T1WI. This study confirms that FS T2WI is useful for the detection of the "edema pattern" in the mandibular condylar associated with TMJ-related pain.

Computational fluid dynamics for investigation of saliva pressure in parotid obstruction

OBJECTIVES/HYOTHESIS: Parotid obstruction is one of the most common problems affecting the parotid gland. We aimed to investigate the blockage ratio (BR) and the intraductal pressure change of Stensen's duct using computational fluid dynamics.

STUDY DESIGN

Retrospective review of 16 patients who had undergone interventional sialendoscopy for parotid obstruction from 2009 to 2011.

METHODS

The three-dimensional configurations of Stensen's duct were reconstructed from computed tomography (CT) sialographic images. Finite volume modeling in fluid dynamics of parotid obstruction was used to analyze the pressure distribution under conditions of rest and stimulation.

RESULTS

Intraductal pressure increased with increasing distance from the orifice. The upstream pressure was higher than that of downstream pressure in the same BR (P < .05). The upstream pressure increased as the BR increased. Statistically, the pressure turning point was indicated when BR = 60%. Only when the BR was much greater than 90% did the pressure reach 811.64 Pa, at which point patients could feel the painful swelling under the rest condition. Under the stimulated condition, the upstream pressure increased from 1.3- to 2.9-fold of that of the no blocking state when the BR increased from 80% to 90%, which may aggravate the obstructive symptoms. There was no significant difference observed for downstream pressure under the same condition (P > .05).

CONCLUSIONS

CT sialography was effectively used for analysis of the intraductal pressure distribution in patients with parotid obstruction. Analysis of salivary fluid dynamics in Stensen's duct may provide a further pathophysiological mechanism for obstructive diseases.

Significance of dynamic magnetic resonance sialography in prognostic evaluation of saline solution irrigation of the parotid gland for the treatment of xerostomia

PURPOSE

To evaluate the clinical significance of dynamic magnetic resonance (MR) sialographic images in prognostic evaluation of saline solution irrigation of the parotid gland for the treatment of xerostomia.

MATERIALS AND METHODS

Morphologic findings and functional parameters were evaluated by use of dynamic MR sialography before saline solution irrigation of the parotid gland for the treatment of xerostomia in 17 patients. In addition, the MR sialographic data before the saline solution irrigation treatment in patients with improvement of salivary secretion and the sensation of dry mouth after irrigation treatment were compared with data in patients without improvement.

RESULTS

The maximum changing ratio in the group of patients with improvement after treatment was significantly higher (P = .042) than that in the group of patients without improvement. In addition, high correlations were found between the changing ratio and improvement on the visual analog scale for dry mouth sensation after treatment (Pearson r = 0.63, P = .001) and improvement of salivary flow rate (Pearson r = 0.77, P = .001). Moreover, in 12 patients with improvement of salivary flow rate after the saline solution irrigation treatment, the maximum changing ratio before the saline solution irrigation treatment was over 1.2. However, no significant differences in other parameters, including the detectable ductal area, were found between the group of patients with improvement after treatment and the group without improvement.

CONCLUSIONS

Our study suggests that dynamic MR sialography might be useful for the prognostic evaluation of saline solution irrigation of the parotid gland for the treatment of xerostomia.

CT virtual sialendoscopy versus conventional sialendoscopy in the visualization of salivary ductal lumen: an in vitro study

OBJECTIVES/HYPOTHESIS

To evaluate the feasibility of computed tomographic (CT) virtual sialendoscopy and its performance characteristics for the visualization of salivary ductal lumen as compared with conventional sialendoscopy.

STUDY DESIGN

An in vitro study.

METHODS

Conventional sialendoscopy was performed in 16 submandibular glands in vitro and the surgical findings were recorded. Then a contrast agent was injected into the Wharton's duct via orifice. After CT scanning, the CT data were transferred to an independent workstation and were postprocessed with commercially available software to generate three-dimensional reconstructive and virtual sialendoscopic images. Finally, the plastination of submandibular glands was performed with 20% perchloroethylene ethyl acetate plastics filler to make cast specimens. CT three-dimensional reconstruction of the ductal system was compared with the cast specimen, and the performance of conventional sialendoscopy and CT virtual sialendoscopy for the visualization of salivary ductal lumen was also compared.

RESULTS

The CT data acquisition and postprocessing protocol were feasible. CT three-dimensional reconstruction enabled clear visualization of the ductal system from any directions and angles, which showed close resemblance to the cast specimens. And CT virtual sialendoscopy created clear endoluminal views of salivary ducts simulating those obtained with conventional sialendoscopy.

CONCLUSIONS

Our initial experience shows that CT virtual sialendoscopy has the potential to be an attractive imaging technique for the visualization of salivary ductal lumen.

Functional evaluations of the parotid and submandibular glands using dynamic magnetic resonance sialography

PURPOSE

To evaluate the functional differences between the parotid and submandibular glands using dynamic MR sialography.

METHODS

In 30 volunteers, the time-dependent changes (dynamic changes) in the maximum area of the detectable parotid and submandibular gland ducts on dynamic MR sialographic images were analysed.

RESULTS

Dynamic changes in the parotid gland ducts were detectable on MR sialographic images in all volunteers, but images of the submandibular gland ducts were detectable in only 23 volunteers. In addition, the dynamic changes in the submandibular gland ducts in these 23 subjects were less than those seen in the parotid gland ducts. A relationship was found between the changing ratio of parotid (Pearson r=0.448, P=0.013) or submandibular gland ducts (Pearson r=0.418, P=0.047) and the salivary flow rate during the stimulation period.

CONCLUSIONS

Dynamic MR sialography allows evaluation of rest and stimulated functioning and morphological evaluation of the parotid and submandibular glands. This technique appears to have many possible applications in the dental, medical and biological fields.

Anterior mandibular lingual salivary gland defect: A report of a case diagnosed with cone-beam computed tomography and magnetic resonance imaging

Anterior mandibular lingual salivary gland defects are rare. They may be evident on routine radiographic exam. Because the differential diagnosis can be exhaustive, differential interpretation and diagnosis are crucial. A case of large bilateral radiolucent lesions of the anterior mandible that was an anterior mandibular salivary gland defect is reported in a young female. This lesion was initially visualized on a panoramic radiograph. Further evaluation was undertaken with dental cone-beam computed tomography. Confirmation of bilateral anterior mandibular lingual salivary gland defects was made using magnetic resonance imaging, negating the need for surgical biopsy.

Application of Magnetic Resonance Virtual Endoscopy as a Presurgical Procedure Before Sialoendoscopy

OBJECTIVES

The objectives of this study were to investigate the feasibility of clinical application of magnetic resonance (MR) virtual endoscopy as a presurgical procedure before sialoendoscopy and to evaluate its value in the diagnosis of obstructive salivary gland diseases and preoperative visualization of endoluminal views.

STUDY DESIGN

This study presents our initial experience to use MR virtual endoscopy for the presurgical visualization of salivary duct lumen and ductal pathologies in comparison to the sialoendoscopy findings in a feasibility study.

METHODS

Six consecutive patients with suspected obstructive salivary gland diseases underwent MR sialography with a three-dimensional fast imaging using steady-state acquisition. The three-dimensional MR data were transferred to an independent workstation and were postprocessed with navigator software to generate three-dimensional reconstruction and virtual endoscopic images. The fly-through mode was used to imitate the sialoendoscopic exploratory procedure. Then the patients underwent sialoendoscopy and the endoscopic findings were compared with the preoperative virtual endoscopic images.

RESULTS

The MR data acquisition and postprocessing protocol were feasible. The virtual endoscopy created clear endoluminal views of salivary duct and the ductal pathologies. The diagnoses were all confirmed by surgical sialoendoscopy. The virtual endoscopic images showed close resemblance to the sialoendoscopic findings.

CONCLUSIONS

MR virtual endoscopy is an effective and noninvasive diagnostic method for evaluating the endoluminal anatomy and pathologies of the salivary duct. The clinical application of MR virtual endoscopy as a presurgical procedure before sialoendoscopy is a valuable and promising approach, which can provide surgeons useful morphologic and pathologic information.

Symmetry of the submandibular glands in humans—a postmortem study assessing the linear morphometric parameters

BACKGROUND

The analysis of morphometric right-left symmetry of the salivary glands is important for assessing unilateral changes discovered in these organs during diagnostic imaging.

STUDY DESIGN

A study was carried out on 18 adult human autopsy neck and maxillofacial specimens from both sexes (14 males, 4 females), with age range of 17 to 73 years (mean age 49.9 years). The submandibular duct was injected with contrast medium and images were made in two projection planes.

RESULTS

Morphometry performed using the obtained radiographs included: (a) caliber (mean proximal, middle, and distal = 1.73 mm, 1.82 mm, and 1.77 mm), (b) length (mean = 37.2 mm); (c) genu of the submandibular duct (mean = 114 degrees ); and (d) longitudinal and transverse diameters of the gland (mean = 44.1 mm and 25.9 mm). Comparison of these morphometric parameters between the right and the left glands revealed no statistically significant differences.

CONCLUSION

There is a high level of right-left symmetry in linear morphometric parameters of the submandibular gland.

Dynamic magnetic resonance sialography as a new diagnostic technique for patients with Sjogren's syndrome

OBJECTIVE

To evaluate the clinical utility of dynamic magnetic resonance (MR) sialographic images as a diagnostic tool for patients with Sjögren's syndrome.

METHODS

The morphological findings and various kinds of functional parameters in volunteers on dynamic MR sialographic images were compared with those in five patients with definite Sjögren's syndrome.

RESULTS

On the MR sialographs of all five patients with Sjögren's syndrome, the so-called 'apple-tree appearance' was seen. The difference in two functional parameters using the dynamic MR sialographic data was elucidated between the two groups. The maximum area of the detectable ducts in the group of patients was significantly smaller (P < 0.001) than that in the group of volunteers. The ratio of change in the detectable ducts in the group of patients was significantly lower (P = 0.011) than that in the group of volunteers.

CONCLUSIONS

Our study suggests that dynamic MR sialographic data in addition to MR sialographic images might be useful for the diagnosis of Sjögren's syndrome.

Relationship of the unstimulated whole saliva flow rate and salivary gland size estimated by magnetic resonance image in healthy young humans

OBJECTIVE

The aim of this study was to examine the relationships between gland sizes and the flow rate and composition of the unstimulated whole saliva in humans.

DESIGN

In 28 healthy young adults, the sizes of the three major salivary glands were estimated by use of a magnetic resonance (MR) imaging technique. Unstimulated whole saliva was collected for 5 min by the spitting method, and the flow rate and the concentrations of total protein, Na(+) and K(+) and pH were measured.

RESULTS

The estimated sizes of the parotid and submandibular glands showed a significant positive correlation with the flow rate and the secretion rate of total protein in the unstimulated whole saliva, but that of the sublingual glands did not. Concerning the concentrations of Na(+) and K(+) and pH, there were no correlations with the salivary gland sizes.

CONCLUSIONS

The results suggest that the larger the sizes of the parotid and submandibular glands, the faster the fluid flow and protein secretion rates in unstimulated whole saliva.

Three-dimensional identification of hemangiomas and feeding arteries in the head and neck region using combined phase-contrast MR angiography and fast asymmetric spin-echo sequences

OBJECTIVE

To evaluate a proposed technique for the 3-dimensional (3D) detection of hemangiomas, including vascular malformation and their feeding arteries, in the head and neck. The new technique combines phase-contrast magnetic resonance angiography (PCMRA) without contrast medium and 3D fast asymmetric spin-echo (FASE) sequences.

METHODS

The technique was applied to 3 patients having hemangiomas in the head and neck region. In 1 patient the image obtained with the proposed technique was compared to that obtained by standard contrast angiography.

RESULTS

In all 3 patients, the 3D presence of the hemangiomas and the feeding arteries were well defined in images created by the proposed technique. Additionally, the characterization of the hemangioma's 3D structure and distribution of the feeding arteries coincided with those observed using contrast angiography in the case for which contrast angiography was also performed.

CONCLUSIONS

Preliminary experience shows that the proposed technique combining 3D-FASE and 3D-PCMRA is useful to visualize both the 3D structure of hemangiomas and to identify the 3D distribution of the feeding arteries without using contrast medium.

The functional evaluation of salivary glands using dynamic MR sialography following citric acid stimulation: a preliminary study

OBJECTIVE

We introduce a new technique for the functional evaluation of the salivary glands using continuous magnetic resonance (MR) sialography before and after citric acid stimulation.

METHODS

In 10 volunteers, the time-dependent changes in the maximum area of the detectable parotid gland ducts on MR sialographic images taken every 30 seconds before and after citric acid stimulation were analyzed. The time period to the occurrence of the maximum duct area poststimulation was noted, and then the time for the area to return to its 50% value pre-citric acid stimulation was also observed. This new technique was clinically applied in 1 patient with an excessive supply impression of saliva and in 1 patient with a short supply impression with saliva.

RESULTS

In all volunteers after citric acid stimulation, the maximum area of the detectable salivary gland ducts first increased and then decreased. A strong relationship was found between the maximum area of the detectable salivary gland ducts before citric acid stimulation and total saliva volume (Pearson r = 0.672, P = .031). Compared with all the volunteers, the ratio of change in the detectable ducts was the highest in the patient with an excessive supply impression of saliva, but lowest in the patient with a short supply impression with saliva.

CONCLUSIONS

This initial study suggests that dynamic MR sialography allows for functional and morphological evaluation of the salivary glands. This technique appears to have many possible applications and further investigation in this field is necessary.

Utility of magnetic resonance cisternography using three-dimensional fast asymmetric spin-echo sequences with multiplanar reconstruction: the evaluation of sites of neurovascular compression of the trigeminal nerve

OBJECTIVE

To evaluate the utility of magnetic resonance (MR) cisternography using 3-dimensional (3D) fast asymmetric spin-echo (FASE) sequences with multiplanar reconstruction (MPR) for detection of the sites of neurovascular compression (NVC) in patients with trigeminal neuralgia.

STUDY DESIGN

Both MR cisternography with 3D-FASE sequences and MR angiography (MRA) were performed on 150 patients with clinical signs and symptoms that suggested trigeminal neuralgia. Results from the original MR cisternography with 3D-FASE sequences, the original MRA, and 4 reformatted images were used for interpretation. Images with inversion between black and white were used from the MR cisternography with 3D-FASE sequences to evaluate NVC. A diagnosis of NVC was made from the presence of vascular contact with the trigeminal nerve at the root entry zone (REZ) and the nature of the involved vessels. For the patients with NVC detectable on 3D-FASE or MRA images, the relationship between the clinically manifested regions and the NVC sites was also evaluated.

RESULTS

Of the 150 patients evaluated, 89 were deemed to have NVC. Of these 89 patients, 3 underwent surgery that identified the artery that was involved with the trigeminal nerve. The correlation between the clinically manifested regions and the NVC sites was significantly detectable using both 3D-FASE images and MRA in 89 patients with detectable NVC. The correlation coefficient using 3D-FASE imaging was a little higher than that using MRA. Of the 61 patients deemed not to have NVC, 6 were found to have brain tumors that invaded the root entry zone of the trigeminal nerve. However, the remaining 55 patients had no identifiable cause for trigeminal neuralgia. NVC was found in the asymptomatic side in 27 (18%) of the 150 patients with trigeminal neuralgia using MR cisternography with 3D-FASE sequences.

CONCLUSIONS

The technique of MR cisternography using 3D-FASE sequences with MPR is more accurate and useful than MRA for detection of the site of NVC in patients with trigeminal neuralgia. Patients with trigeminal neuralgia should be further examined using MR imaging to rule out a brain tumor. Radiologists should understand that a few subjects with no symptoms could show NVC with MR cisternography.

Utility of diffusion-weighted images using fast asymmetric spin-echo sequences for detection of abscess formation in the head and neck region

OBJECTIVE

The objective of this study was to evaluate the utility of new diffusion-weighted magnetic resonance images (DWI) using fast asymmetric spin-echo (FASE) sequences for the detection of abscess formation in patients with phlegmon in the oral and maxillofacial regions.

METHODS

We compared diffusion-weighted images using FASE sequences with those using the gradient-echo type of echo-planar images (EPI) in 10 control volunteers and 10 patients with phlegmon in the oral and maxillofacial regions.

RESULTS

Many kinds of tissues in the oral and maxillofacial regions were relatively well visualized in all subjects on FASE-DWI, but not well on EPI-DWI. Apparent diffusion coefficients calculated from FASE sequences in abscess areas of patients with phlegmon were significantly lower than those in abscess-free areas; however, apparent diffusion coefficients calculated from EPI were not significantly different due to prominent distortion in small sample size study.

CONCLUSIONS

We could accurately recognize the presence of abscess formation within inflammatory tissue in 5 patients with phlegmon using FASE-DWI. As an additional magnetic resonance examination, FASE-DWI might be useful in the detection of abscess formation in the oral and maxillofacial regions.

Xerostomia Secondary to Sj??gren???s Syndrome in the Elderly

Xerostomia is a common symptom in the elderly population. Studies have suggested that the underlying cause of approximately 40% of xerostomia in the elderly is Sjögren's syndrome. Although it is highly prevalent among middle-aged individuals, elderly patients account for up to 20% of Sjögren's syndrome cases. Sjögren's syndrome is a multisystem exocrinopathy characterised by dry mouth and dry eyes with wide-ranging extraglandular involvement. The exocrine manifestations of Sjögren's syndrome affect the mouth, eyes, nose, ears, skin, vagina and the entire respiratory and gastrointestinal systems. The nonexocrine involvement may include the joints, thyroid gland, liver, kidneys and the musculoskeletal, vascular and central nervous systems. Currently, the mechanism(s) of development and progression of Sjögren's syndrome is/are not clear. Inflammation and lymphocytic infiltration of the exocrine glands is a classical feature of Sjögren's syndrome. During the progression of the disease, the acinar cells of the exocrine glands are replaced by fibrosis, rendering the glands nonfunctional. Sjögren's syndrome remains one of the most underdiagnosed conditions, particularly in the elderly population, because the cardinal sicca symptoms, which are the hallmark of the disease, are frequently attributed to aging and/or medications, which consequently delays the diagnosis. This delay in diagnosis imposes significant physical, psychological and economic burdens on elderly patients. The diagnosis of Sjögren's syndrome requires evaluation of both the exocrine and nonexocrine components of the disease. Management of Sjögren's syndrome requires collaboration by the primary-care physician, rheumatologist, ophthalmologist and dentist. This article reviews current understanding of the clinical manifestations, diagnosis and treatment of Sjögren's syndrome with special emphasis on the oral component of the disease.

Utility of three dimension fast asymmetric spin-echo (3D-FASE) sequences in MR sialographic sequences: model and volunteer studies

OBJECTIVES

To evaluate the utility of 3D-FASE for the visualization of salivary gland ducts for use in MR sialographic sequences.

METHODS

We compared MR sialographic images and virtual endoscopic views from 3D-FASE with those from three kinds of sequences described by previous reports in a 3D parotid gland duct model and volunteer. The four sequences were two-dimension fast spin-echo (2D-FSE), three-dimension fast spin-echo (3D-FSE), two-dimension fast asymmetric spin-echo (2D-FASE), and three-dimension fast asymmetric spin-echo (3D-FASE).

RESULTS

In the 3D parotid gland duct model, image visibility on visual score was clearest with 3D-FSE, followed by 3D-FASE (P = 0.028). In the volunteers, the visualization of images improved in the following order: 3D-FASE > 3D-FSE > 2D-FSE > 2D-FASE.

CONCLUSIONS

The technique of 3D-FASE sequencing is more suitable and useful for MR sialography with an appropriate acquisition time.

Clinical application of magnetic resonance sialographic 3-dimensional reconstruction imaging and magnetic resonance virtual endoscopy for salivary gland duct analysis

PURPOSE

In a previous study, we showed that the new and fast sequence 3-dimensional (3D)-fast asymmetric spin-echo sequencing could be applied in magnetic resonance (MR) sialographic 3D reconstruction imaging of the parotid gland ducts and in producing virtual endoscopic views of the parotid gland with MR data.

MATERIALS AND METHODS

In the present study, we examined the clinical application of these MR sialographic 3D reconstruction imaging and virtual endoscopy of the salivary gland ducts using MR data sets with 3D-fast asymmetric spin-echo sequencing.

RESULTS

The MR sialographic 3D reconstruction images showed a complete view in the branch paths from all angles, and the MR virtual endoscopic views showed conditions in the endoluminal tracts of the large branches in 20 patients with salivary gland duct abnormalities, including Sjögren syndrome, cyst, tumor, sialadenitis, and salivary calculi.

CONCLUSION

The clinical use of MR sialographic 3D reconstruction imaging and MR virtual endoscopy for salivary gland ducts may enhance understanding of the 3D relationship between the ducts and the surrounding tissue, as well as the endoluminal circumstance within ducts. Possible future applications abound, and further investigation in this field is expected.

Detection and significance of the characteristic magnetic resonance signals of mandibular condyles in children

OBJECTIVE

We sought to determine the magnetic resonance imaging (MRI) characteristics of mandibular condyles in still-growing children. In addition, we also evaluated the significance of the double-contour-like structure and the conversion from red to yellow marrow characteristic of this age.

METHODS

The MRI characteristics of mandibular condyles were determined by means of fast spin-echo intermediate-weighted images in subjects 9 to 14 years old. In 1 subject who developed temporomandibular joint-related clinical symptoms 1 year later, MRI was re-performed at that time.

RESULTS

With the use of MRI, a total of 17 double-contour-like structures were detected in 42 temporomandibular joints of 9- to 14-year-olds, but neither 50 healthy joints of youths nor adults. In terms of bone marrow signal changes, the turning point was found to be 11 years old. In 1 subject, the double-contour-like structures were not visible on the MR images obtained 1 year after the first examination.

CONCLUSION

The double-contour-like structure and the periods of conversion from red to yellow marrow may be able to be used as part of the criteria for the staging of mandibular condyle development in children.

Instability of background fat intensity suppression using fat-saturated (FS) MR imaging techniques according to region and reconstruction procedure in patients with oral cancer

The purpose of the present study is to evaluate the background fat intensity suppression instability of each area in the head and neck region, and in the post-reconstruction with metal plate and myocutaneous flap, of patients with oral cancer using fat-saturated (FS) images. STIR and FS T2-weighted images at pre- and post-surgery in 59 patients with oral cancer were scored for uniformity of fat suppression and tissue conspicuity in each region of the head and neck. The scores of FS on uniformity of fat suppression pre-operatively were worse than those of STIR in the mandibular level, but not lesion and tissue conspicuity. However, the deterioration both of scores between pre- and post-surgery using FS was worse than that using STIR using metal plate and/or myocutaneous flap. At diagnosis, we should recognize on MR images using FS that instability of the status of fat suppression might be brought about by respective area and reconstruction with metal plate and myocutaneous flap of patients with oral cancer.