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Biomedical subjects

K Yonetsu

Publications and source records attributed to K Yonetsu.

29 records · Page 2Linked to original sources

A remote conference system for image diagnosis on the World-Wide Web.

OBJECTIVE: The World-Wide Web on the Internet enables an exchange of multimedia information among remote desktop computers. Therefore, a teleradiology system using the Web would allow remote consultation with expert radiologists. Our objective was to establish a Web-based prototype system for image interpretation. CONCLUSION: Our system allows a physician to transmit clinically useful images to an expert radiologist at a different location, who can see them on a Web browser and discuss diagnoses with the physician.

Computer Communication Networks↗

Diagnostic value of magnetic resonance imaging for malignant tumors in the oral and maxillofacial region.

The purpose of this study was to clarify the diagnostic value of magnetic resonance imaging for malignant tumors in the oral and maxillofacial region. Computed tomography and magnetic resonance images of 25 patients with malignant tumors of the oral and maxillofacial region were evaluated. Computed tomography scans were performed with intravenous contrast enhancement. A 0.2-Tesla (Hitachi Medical Corp., Tokyo, Japan) permanent magnetic resonance unit was used to obtain T1-, T2-, and proton-density-weighted images with spin-echo pulse sequences. Gadolinium-diethylene-triamine-pentaacetic acid was administered in 11 cases. Severe artifacts influencing image interpretation were observed in 10 (40%) cases on computed tomography but only in 5 (20%) cases on magnetic resonance imaging. There was no difference in the detectability of bone invasion between images from the two systems. Contrast enhancement with gadolinium-diethylene-triamine-pentaacetic acid provided additional useful information in only 3 of 11 cases compared with nonenhanced magnetic resonance images. Malignant tumors showed a higher signal intensity than that of muscle on T2-weighted images in all cases and on proton-density-weighted images in 23 (92%) cases. On T1-weighted images, an intermediate signal intensity similar to that of muscle was seen in 16 (64%) cases and a hyperintense signal in 9 (36%) cases. There was poor correlation between signal intensity and pathologic diagnosis of the tumors. These results suggest that in cases with severe artifacts that disturb the interpretation of the images on computed tomography, magnetic resonance examinations are preferable for defining the exact extent of the primary lesion.

Adult↗

Quantitative analysis of the submandibular gland using computed tomography.

OBJECTIVE: To evaluate the normal variation in size of the submandibular gland from computed tomographic (CT) scans. MATERIALS AND METHODS: CT was performed parallel to the Frankfurt horizontal (FH) and mandibular (MP) planes in 130 subjects (64 men and 66 women) with healthy submandibular glands, six patients with sialoadenitis and four with masseteric hypertrophy. RESULTS: The mean (s.d.) maximum cross-sectional area (MCSA) of the submandibular glands for FH was 324 (89) mm2 and for MP 364(101) mm2. There was a high correlation between individuals' right and left glands. There was no significant difference in the mean MCSA between the right and left, which varied by less than 10%. The mean (s.d.) volume of the gland was 8072 (2574) mm3. With a high correlation with mean MCSA in both scanning planes, the mean MCSA may be an indicator of the volume of the gland. MCSA increased significantly with body height, weight and body mass index, but decreased with age. The MCSA of the affected side in patients with sialoadenitis and masseteric hypertrophy was larger than both that of the normal side and the predicted values. CONCLUSION: MCSA is a useful indicator of gland volume, and differences of greater than 10% between the two sides may be used in the diagnosis of submandibular gland disease.

Adult↗

Central squamous cell carcinoma of the mandible. Computed tomographic findings.

Five cases of central squamous cell carcinoma of the mandible were investigated with the use of computed tomography. Bucco-lingual extent and spread along the mandibular division of the trigeminal nerve were evaluated. Three patients with trismus showed involvement of the masseter or medial pterygoid muscle on computed tomography. Involvement of more than two landmarks along the trigeminal nerve were observed in cases with both paresthesia of the lower lip and severe pain that resembled neuralgia. Perineural invasion was confirmed histologically in four cases, and all of these patients had both severe pain and mandibular canal involvement that could be demonstrated with computed tomography. When localized soft tissue changes are evident along the course of the trigeminal nerve in the region between the mandibular foramen and foramen ovale, ascending perineural spread should be suspected. Computed tomography findings correlated well with clinical symptoms but added information about the spread of the lesion within the surrounding soft tissue.

Carcinoma, Squamous Cell↗

Magnetic resonance imaging of oral and maxillofacial angiomas.

Eleven patients with oral and maxillofacial angiomas (seven hemangiomas and four lymphangiomas) were evaluated with magnetic resonance imaging using a 0.2-T permanent system and spin-echo pulse sequences. These lesions typically had signal intensities that were iso T1-weighted, similar to muscle, and high T2-weighted, greater than subcutaneous fat. Nine tumors had well- or relatively well-defined margins, and seven cases had curvilinear structures of low signal intensities in the masses on T2-weighted images. It was impossible to distinguish hemangiomas from lymphangiomas on MR images. Our experience suggested that most angiomas of oral and maxillofacial regions present special characteristics on magnetic resonance images. It is thought that information obtained with magnetic resonance images can contribute significantly to the evaluation of the extent of these lesions.

Adolescent↗

Computed tomography of the jaws in familial adenomatosis coli.

Familial adenomatosis coli is known to be associated with tooth impactions, odontomas, and osteomas. Three cases were examined by panoramic radiography and computed tomography. Computed tomography was especially useful for detecting osteomas in the maxilla and also revealed a wavy cortical thickening in the mandible in one instance. The latter finding has been reported for other bones in the body but not previously for the mandible.

Child↗

Analysis of maxillary sinusitis using computed tomography.

Odontogenic maxillary sinusitis can be defined as sinusitis induced by a dental lesion. We examined the CT findings of 68 patients with maxillary sinusitis in order to differentiate between inflammation of sinus origin and inflammation of dental origin. Maxillary sinusitis was classified into four types according to clinical symptoms, history and conventional radiographic findings: type 1, simple sinusitis; type 2, odontogenic sinusitis; type 3, mixed sinusitis; type 4, slight sinus abnormality with a dental lesion. The relationship between the type of maxillary sinusitis and CT findings was analysed. Type 1 sinusitis exhibited severe pathological changes in both mucosa and bone which often extended into the nasal cavity and other paranasal sinuses. Type 2 sinusitis exhibited localized pathology on the unilateral antral floor. Type 3 sinusitis exhibited severe pathology characteristic of type 1 combined with type 2 sinusitis. Type 4 sinusitis could be differentiated by the CT findings into type 1 or type 2 sinusitis. The classification of sinusitis in this manner has implications for treatment planning, and CT should therefore be performed when conventional radiography does not provide sufficient information.

Female↗

Salivary SPECT and factor analysis in Sjögren's syndrome.

Salivary SPECT and factor analysis in Sjögren's syndrome were performed in 17 patients and 6 volunteers as controls. The ability of SPECT to detect small differences in the level of uptake can be used to separate glands from background even when uptake is reduced as in the patients with Sjögren's syndrome. In control and probable Sjögren's syndrome groups the uptake ratio of the submandibular gland to parotid gland on salivary SPECT (S/P ratio) was less than 1.0. However, in the definite Sjögren's syndrome group, the ratio was more than 1.0. Moreover, the ratio in all patients with sialectasia, which is characteristic of Sjögren's syndrome, was more than 1.0. Salivary factor analysis of normal parotid glands showed slowly increasing patterns of uptake and normal submandibular glands had rapidly increasing patterns of uptake. However, in the definite Sjögren's syndrome group, the factor analysis patterns were altered, with slowly increasing patterns dominating both in the parotid and submandibular glands. These results suggest that the S/P ratio in salivary SPECT and salivary factor analysis provide additional radiologic criteria in diagnosing Sjögren's syndrome.

Adult↗

Ultrasonographic study of the relation of metastatic nodes to the carotid artery.

Ultrasonographic studies of the neck were performed in four patients with metastatic lymph nodes that exhibited limited mobility or fixation to the surrounding tissues on palpation to obtain information about the relationship of nodes to the carotid artery. Comparison of the ultrasonograms with the operative findings disclosed that when a metastatic lymph node adhered to the carotid artery, the lymph node pulsated with flattening of the carotid artery and the echoes between the metastatic lymph node and carotid artery were attenuated.

Aged↗

Unusual CT appearance in an odontogenic keratocyst of the mandible: case report.

An expansile lesion in the body of the left mandible had high attenuation (225 HU) on nonenhanced CT scans. Histologic examination revealed an odontogenic keratocyst with no evidence of mineralization or calcification within the lesion. The high attenuation was considered to be due to highly concentrated protein of thick, viscous keratin in the lumen of the keratocyst.

Adult↗