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K Yonetsu

Publications and source records attributed to K Yonetsu.

At least 19 recordsLinked to original sources
PubMed2003

Curvature analysis of the mandibular condyle.

OBJECTIVE: To determine whether curvature analysis on high resolution CT images can be used as a tool for evaluation of mandibular condyle morphology. METHODS: Curvature analysis was performed on reconstructed oblique coronal CT images of 634 normal condyles from 317 patients (144 men and 173 women; age range 4-89 years) with inner or middle ear disease. The condyles were scanned with 1 mm collimation using helical CT. The CT images were analysed manually on a personal computer. RESULTS: The condyle CT images could be categorized into five curvature profile patterns: (1) bi-peak; (2) no peak; (3) tri-peak; (4) bi-peak with an intervening bottom above the base line (bi-peak with a col); and (5) bi-peak with an intervening negative phase. A separate evaluation using computer graphic condyle models indicated that these curvature patterns corresponded to flat (bi-peak), round (no peak), convex (bi-peak with a col), concave (bi-peak with a negative phase) and angled (tri-peak) contours of the condyle's superior surface. The curvature profiles were identical between bilateral condyles in 40% (126/317) of the patients. Gender-related differences in the incidence of the curvature profiles were also found, the bi-peak with a col profile being more frequently observed in women and the bi-peak with a negative phase profile being observed more frequently in men. CONCLUSION: Curvature analysis on CT images depicts condyle morphology effectively and may be an adjunctive tool for condyle morphometry.

Adolescent↗
PubMed2001

Contribution of doppler sonography blood flow information to the diagnosis of metastatic cervical nodes in patients with head and neck cancer: assessment in relation to anatomic levels of the neck.

BACKGROUND AND PURPOSE: Although sonographic evaluation of cervical adenopathy by use of size criteria is effective, the sensitivity and specificity fall short of that required to make adequate judgments regarding neck dissection. Therefore, we tested whether the combined use of size criteria and Doppler sonographic findings would improve the predictive ability for metastatic cervical nodes. METHODS: We analyzed 338 histologically proved cervical lymph nodes (108 metastatic and 230 nonmetastatic) in 73 patients with head and neck cancer. The sonographic topography of the nodes was compared with dissected specimens, and their position in the neck was categorized into three levels (I, II, and III+IV). The diagnostic accuracy of sonography was evaluated by using the single criterion of short-axis diameter of the node or by the combined criteria of short-axis diameter and Doppler blood flow features (the absence or presence of normal hilar flow). RESULTS: As compared with the single criterion of short-axis nodal diameter, the combined criteria of nodal size and Doppler blood flow patterns increased the diagnostic accuracy of sonography at all levels in the neck. Accordingly, the best cut-off values were improved to 6, 7, and 5 mm for nodes at levels I, II, and III+IV, respectively. In addition, the combined criteria yielded high sensitivites (> or = 89%) and specificities (> or = 94%). CONCLUSION: Hilar blood flow information obtained by Doppler sonography significantly improves diagnostic accuracy for the detection of nodes metastatic from head and neck squamous cell carcinoma.

Aged↗
PubMed2000

Standardization of 3-D CT measurements for length and angles by matrix transformation in the 3-D coordinate system.

OBJECTIVE: We attempted to establish a new 3-D cephalometry with helical computed tomography (CT) by introducing the matrix transformation of the 3-D coordinate system. SUBJECTS AND METHODS: Three-dimensional cephalometric landmarks on the craniofacial bones were expressed as 3-D vectors originating from the center of the sella. These vectors were standardized by the matrix transformation so that the midsagittal plane and cranial base line coincided with the XZ plane and X axis of the 3-D coordinate system, respectively. We also applied this new method to trace the normal growth of the craniofacial bones in 44 patients with head and neck cancer (age range, 5 to 26 years; 19 women and 25 men). RESULTS: The accuracy for length measurements was less than 3% of standard error of means with a slice thickness of 1 or 3 mm for 28 out of the 29 length measurements recorded. The precision errors by repeated measurements were 0.8% to 1.0% coefficients of variation for intra- and interobserver variability. Standardization of 3-D vectors representing the cephalometric landmarks allowed us to assess successfully the age-related transition of these landmarks of the patients' craniofacial bones. CONCLUSION: A new assessment method for 3-D CT cephalometry has been developed by standardizing cephalometric landmarks using a matrix transformation of the 3-D coordinate system. This new assessment method may offer potential in planning plastic and reconstructive surgery.

Adolescent↗
PubMed2000

Age-related expansion and reduction in aeration of the sphenoid sinus: volume assessment by helical CT scanning.

BACKGROUND AND PURPOSE: Aeration of the sphenoid sinus expands with the development of the sphenoid bone, but scant detailed volumetric data regarding this process, as it evolves from childhood to old age, exist. Using helical CT scanning, we assessed age-related volumetric changes of the sphenoid sinus. METHODS: We used CT data obtained from 214 patients (age range, 1 to 80 years; 111 male and 103 female subjects) with middle or inner ear disease to assess the extent of sphenoid aeration. We also determined volumes of the sphenoid sinuses on 1.0- or 1.5-mm reformatted images by integrating the sinus air (< or = -900 HU) area. RESULTS: Sphenoid sinus aeration began as a doublet in the anterior boundary of the sphenoid bone by the age of 5 years, with patients more than 6 years old exhibiting varying degrees of aeration. The aeration on both sides continued to expand until the third decade of life. The maximum average volume was 8.2 +/- 0.5 cm3. Thereafter, the volume decreased gradually, with the average volume in the seventh decade of life being 71% of the maximum level. The aeration of the peripheral portions of the sphenoid bone, such as the pterygoid process, anterior clinoid process, and dorsum sella, occurred predominantly after closure of the spheno-occipital suture, and showed a tendency to recede during aging. CONCLUSION: Volumetric assessment of the sphenoid sinus by helical CT scanning revealed age-related expansion and reduction in aeration.

Adolescent↗
PubMed2000

Multivariate feature analysis of sonographic findings of metastatic cervical lymph nodes: contribution of blood flow features revealed by power Doppler sonography for predicting metastasis.

BACKGROUND AND PURPOSE: Sonographic criteria of the lymph node have been found to be good indicators for metastatic lymph nodes. We determined which sonographic features are most predictive of metastasis in cervical lymph nodes among patients with head and neck cancer. METHODS: Gray-scale and power Doppler sonograms were retrospectively analyzed in 133 cervical lymph nodes (57 metastatic and 76 reactive nodes) from 52 patients with head and neck cancer. The gray-scale sonographic features of the presence or absence of hilar echoes, parenchymal echogenicity, and short and long axis lengths as well as the power Doppler features of normal hilar flow and abnormal parenchymal flow were evaluated. Univariate and multivariate logistic regression analyses were conducted to determine the relative value of each sonographic feature. RESULTS: At univariate analysis, all sonographic features assessed were found to be important. Multivariate analysis, however, suggested that the presence or absence of hilar echoes, increases in short axis length, and the presence of normal hilar flow were the only sonographic features that were predictive of reactive (presence of hilar echoes and hilar flow) and metastatic (increases in short axis length) lymph nodes. Although multivariate analysis did not indicate any significant contribution of the color-flow criteria for predicting metastatic nodes, the color-flow criteria appeared to improve the overall diagnostic accuracy for the less experienced observer. CONCLUSION: The sonographic criteria most predictive of metastatic cervical lymph nodes were absent hilar echoes and increases in short axis length, as assessed by logistic regression analysis. Compared with these gray-scale criteria, color-flow criteria had fewer predictive advantages.

Adult↗
PubMed2000

Abnormal blood flow to the submandibular glands of patients with Sjögren's syndrome: Doppler waveform analysis.

OBJECTIVE: To assess abnormalities in blood flow to the submandibular glands of patients with Sjögren's syndrome (SS). METHODS: Doppler waveform analysis was performed on the facial artery to assess blood inflow to the submandibular gland of 21 patients with primary SS and 69 healthy subjects. Blood flows were compared before and after secretory stimulation with lemon extracts. RESULTS: The facial artery of healthy subjects in the resting state exhibited a biphasic waveform with a high systolic peak and a prominent second peak of compliance followed by a low diastolic flow. In contrast, the waveform of patients with SS was more uniform compared with the healthy subjects, substantiated by decreased resistive and pulsatility indices, suggesting a hyperemic state of the downstream vascular bed. After stimulation of salivary secretion, the facial artery of healthy subjects responded by decreasing resistive and pulsatility indices, waveform changes indicative of increased blood inflow to the submandibular gland. In contrast, the facial artery of patients with SS responded insufficiently to the stimulation, with the magnitude of changes in the resistive and pulsatility indices being significantly lower than those of the controls. Doppler waveform abnormalities were correlated with the severity of gland damage, supporting a close connection between abnormal blood inflow to the salivary gland and impaired secretory function in SS. CONCLUSION: Our findings suggest that blood inflow responses to secretory stimulation may be defective in the salivary glands of patients with SS.

Adult↗
PubMed1999

Value of contrast-enhanced magnetic resonance imaging in differentiation of hemangiomas from lymphangiomas in the oral and maxillofacial region.

OBJECTIVE: The purpose of this study was to investigate the ability of contrast-enhanced magnetic resonance imaging to differentiate hemangioma from lymphangioma in the oral and maxillofacial region. STUDY DESIGN: Contrast-enhanced magnetic resonance imaging was performed in 20 patients (21 masses: 17 hemangiomas and 4 lymphangiomas) through use of either a 0.2-T permanent system or a 0. 5-T superconductive system and spin-echo pulse sequences. RESULTS: After intravenous administration of contrast medium, enhancement was observed in all hemangiomas in areas corresponding to those with high signal on T(2)-weighted images. Unequivocally increased signal was observed in 10 masses, and slightly increased signal was observed in 7 masses. On the other hand, none of the lymphangiomas showed an enhancing mass on contrast-enhanced T(1)-weighted images. CONCLUSIONS: Although contrast-enhanced T(1)-weighted imaging may not improve delineation of masses in all cases, it can be used to differentiate between deep hemangiomas and lymphangiomas.

Adolescent↗
PubMed1999

Sublingual gland: MR features of normal and diseased states.

OBJECTIVE: We describe the MR features of the sublingual gland in normal and diseased states. SUBJECTS AND METHODS: We used MR imaging to assess age-related changes in size and signal intensity of normal sublingual glands in 60 control subjects. The MR features of sublingual glands were also studied in 70 patients with cancer, cellulitis of the sublingual space, Sjögren's syndrome, or ranula. RESULTS: MR imaging efficiently revealed normal sublingual glands. On T1-weighted images, the MR signal intensity of the sublingual gland was lower than that of the surrounding fat but higher than that of muscle. The sublingual glands showed age-related decreases in size, with approximately 25% of the thickness present in the second decade of life being lost by the seventh decade. T1-weighted signal intensity of the parotid gland increased with age, but the signal intensity of the sublingual and submandibular glands did not. T1-weighted signal intensity of carcinomas in and near the sublingual space was lower than that of the sublingual glands, but T2-weighted signal intensity of carcinomas exceeded that of the glands. Gadolinium enhancement occasionally diminished the contrast between invading carcinomas and the glands. T1-weighted MR imaging showed that sublingual glands affected by Sjögren's syndrome exhibit features analogous to those of the other major salivary glands; however, the sublingual glands seemed to be less severely involved overall in this syndrome than the other major glands. We found that using fat suppression and short inversion time inversion recovery may be useful for assessment of sialadenitis of the gland. CONCLUSION: MR imaging is useful in depicting normal and diseased states of the sublingual gland.

Adolescent↗
PubMed1999

The MR imaging assessment of submandibular gland sialoadenitis secondary to sialolithiasis: correlation with CT and histopathologic findings.

BACKGROUND AND PURPOSE: MR imaging has been proved to be effective in depicting wide variety of pathologic changes of the salivary gland. Therefore, we evaluated clinical usefulness of MR imaging for sialolithiasis. METHODS: Sixteen patients with sialolithiasis of the submandibular gland underwent MR imaging. MR images of the glands were obtained with a conventional (T1-weighted), fast spin-echo (fat-suppressed T2-weighted) and short inversion time-inversion recovery sequences. Contrast enhancement was not used. MR imaging features then were compared with clinical symptoms, histopathologic features of excised glands, and CT imaging features. RESULTS: Submandibular glands with sialolithiasis could be classified into three types on the basis of clinical symptoms and MR imaging features of the glands. Type I glands were positive for clinical symptoms and MR imaging abnormalities, and were characterised histopathologically by active inflammation (9 [56%] of 16). Type II glands were negative for clinical symptoms and positive for MR imaging abnormalities (4 [25%] of 16), and the glands were replaced by fat. Type III glands were negative for clinical symptoms and MR imaging abnormalities (3 [19%] of 16). CT features of these glands correlated well with those of MR imaging. CONCLUSION: These results suggest that MR imaging features may reflect chronic and acute obstruction, and a combination of CT and MR imaging may complement each other in examining glands with sialolithiasis.

Adipose Tissue↗
PubMed1998

Imaging findings of some buccomasseteric masses.

OBJECTIVE: The purpose of this study was to review and illustrate the appearances on diagnostic images of pathologic conditions of the buccomasseteric region. STUDY DESIGN: Computed tomographic, sonographic, and magnetic resonance images of the buccomasseteric masses were reviewed retrospectively. RESULTS: In our series of 66 cases, there were 60 benign lesions; of these, 21 were benign masses, 11 were inflammations, and 28 were myopathies. The most common pathologic condition of the buccomasseteric region was masseteric hypertrophy (n = 22). The most common lesion manifesting as a benign mass in this series was hemangioma (n = 10), which was followed by lipoma (n = 6). Six of the 66 patients had malignant tumors. CONCLUSIONS: Computed tomography and magnetic resonance imaging were useful in demonstrating the location and extent of the buccomasseteric masses. Sonography provided clear images of internal architectures of the mass in this region.

Adolescent↗
PubMed1998

Deep facial infections of odontogenic origin: CT assessment of pathways of space involvement.

PURPOSE: We investigated the pathways of spread of odontogenic infection in the facial and neck spaces. METHODS: CT scans of 45 patients with extensive spread of odontogenic infection into the facial and neck spaces were analyzed to document pathways of spread. RESULTS: Odontogenic infections arising in the mandible first spread upward, into the masseter and/or medial pterygoid muscles in the masticator space, and downward, into the sublingual and/or submandibular spaces, and then spread into the spaces or muscles adjacent to one or more of these locations. Infections from the masseter muscle spread into the parotid space to involve the temporalis and lateral pterygoid muscles. Infections from the medial pterygoid muscle spread into the parapharyngeal space to involve the lateral pterygoid muscle. Infections in the maxilla did not spread downward; instead, they tended to spread upward and superficially into the temporal and/or masseter spaces and deeply involve the lateral and/or medial pterygoid muscles in the medial masticator space. CONCLUSION: CT may be useful to depict the extent of infection and to plan treatment of extensive odontogenic infection, which can be life threatening when therapy is ineffective.

Adolescent↗
PubMed1998

Power Doppler sonography of cervical lymph nodes in patients with head and neck cancer.

PURPOSE: The purpose of this preliminary study was to evaluate the usefulness of power Doppler sonography in differentiating metastatic from nonmetastatic cervical lymph nodes in patients with cancer. METHODS: Histologically proved metastatic (n = 71) and nonmetastatic (n = 220) lymph nodes were examined with power Doppler sonography in 77 patients with head and neck cancer. Power Doppler sonography was assessed for its ability to differentiate metastatic from nonmetastatic lymph nodes. RESULTS: Power Doppler sonography showed characteristic features of parenchymal blood flow signal in 59 (83%) of the 71 metastatic lymph nodes. By contrast, only four (2%) of the 220 nonmetastatic nodes showed these power Doppler signals. In addition, power Doppler sonography showed high levels of sensitivity (83%) and specificity (98%) in depicting metastatic lymph nodes, which were superior to the values (66% sensitivity and 92% specificity) obtained by applying size criteria (transverse to longitudinal ratio). However, a combination of the two criteria (parenchymal color signal and transverse to longitudinal ratio) improved diagnostic accuracy to 92% sensitivity and 100% specificity. CONCLUSION: Our preliminary findings suggest that the power Doppler criteria of no hilar flow, peripheral parenchymal nodal flow, and a transverse to longitudinal ratio of more than 0.65 together constitute a powerful tool for depicting metastatic lymph nodes in patients with cancer.

Adult↗
PubMed1997

Idiopathic osteosclerosis of the jaws: panoramic radiographic and computed tomographic findings.

OBJECTIVE: The purpose of this study was to determine the frequency and anatomic location of idiopathic osteosclerosis in the jawbones and to present computed tomographic findings of this lesion in Japanese patients. STUDY DESIGN: Panoramic radiographs of 1047 patients were examined for the presence of idiopathic osteosclerosis in the jawbones. Computed tomography was performed in 11 patients of this series. RESULTS: A total of 64 patients (6.1%) showed this radiopacity. The highest occurrence was in the mandibular first molar region. There was no statistically significant difference in the prevalence of idiopathic osteosclerosis between males and females. On computed tomography images, these radiopaque areas were divisible into two types: enostosis (five cases) and central sclerosis (six cases). CONCLUSION: This is the first report of computed tomographic findings on idiopathic osteosclerosis in the jawbones, although the results on panoramic radiographs are similar to other investigators.

Adolescent↗
PubMed1997

Reliability of ultrasonography and sialography in the diagnosis of Sjögren's syndrome.

OBJECTIVE: The purpose of this study was to evaluate quantitatively observer performance with ultrasonography and sialography in the diagnosis of parotid gland involvement of Sjögren's syndrome. STUDY DESIGN: Sixty-four parotid gland sialograms and 65 ultrasonograms were prepared for observer performance experiments. They included both modalities in 24 Sjögren's syndrome and 19 nonspecific parotitis cases, 21 normal parotid gland sialograms, and 22 normal ultrasonograms in healthy volunteers. The images were randomly sequenced and presented to five observers who were asked to describe several findings and finally to determine the imaging diagnosis by ranking the abnormal features and the diagnosis on a five-point-rating scale. Observer performance was evaluated on the basis of the reliability of findings interpreted and the diagnostic accuracy of each modality from observers' rating scores. RESULTS: The diagnostic accuracy of sialography was very high, nearly perfect. The diagnostic accuracy of ultrasonography was lower than that of sialography, resulting from the lower incidence of characteristic findings in the disease groups and lower sensitivity on ultrasonography. In the differentiation of Sjögren's syndrome from the normal, however, the diagnostic accuracy of ultrasonography increased to 80% for all cases, and up to nearly 90% in the advanced sialographic stages. CONCLUSION: Ultrasonography is useful for the diagnosis of Sjögren's syndrome in the advanced stages. Taking the noninvasiveness of this technique into account we recommend first applying ultrasonography to the diagnosis of Sjögren's syndrome and performing sialography when no positive findings are detected on ultrasonography.

Analysis of Variance↗
PubMed1997

Imaging findings of lipomas in the orofacial region with CT, US, and MRI.

OBJECTIVE: The aim of this study was to document retrospectively the imaging findings of lipomas with the use of computed tomography, ultrasonography, and magnetic resonance imaging. STUDY DESIGN: Thirteen patients with 11 lipomas and 2 lipomatoses were evaluated. Eleven cases were examined by computed tomography, 9 by ultrasonography, and 3 by magnetic resonance imaging. RESULTS: Lipomas had a density ranging from -134 to -83 Hounsfield units, (mean-108) on the computed tomography images. The margins were ill defined in 9 of 10 cases. The superficial muscles were displaced externally in 8 cases and internally in 2 cases. With ultrasonography, 8 lesions were hypoechoic, and one was hyperechoic. All three lesions had a high signal intensity on both T1- and T2-weighted images. CONCLUSIONS: Lipomas had a specific range of computed tomography Hounsfield unit values and also displaced the surrounding soft tissue. Although some variation in the ultrasonographic appearance was observed, the lesions tended to be hypoechoic. These findings may be useful for diagnosing lipomas in the orofacial region.

Adolescent↗