Miki Hisatomi
Okayama University
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Featured researches published by Miki Hisatomi.
European Journal of Radiology | 2003
Miki Hisatomi; Jun Ichi Asaumi; Hironobu Konouchi; Hiroshi Shigehara; Yoshinobu Yanagi; Kanji Kishi
The aim of the present study was to review the magnetic resonance (MR) appearance of primary epithelial cysts in order to distinguish the cysts from other possible lesions. MR images were obtained in 27 cases of epithelial cysts, including 7 odontogenic keratocysts, 3 dentigerous cysts, 1 glandular odontogenic cyst, 10 radicular cysts, 4 nasopalatine duct cysts, and 2 nasolabial cysts. In addition, contrast enhanced MR imagings were performed in 12 cases, including 3 odontogenic keratocysts, 1 dentigerous cyst, 1 glandular odontogenic cyst, and 7 radicular cysts. We obtained the following results on the basis of the above MR and contrast enhanced MR findings. (a) Odontogenic keratocysts had a predilection for intermediate-high signal intensity (SI) on T1-weighted images (WI) and heterogeneous low-high SI on T2WI. (b) Dentigerous cysts, glandular odontogenic cyst, radicular cysts and nasolabial cysts showed the same predilection with the SI, which were homogeneous intermediate SI on T1WI and homogeneous high SI on T2WI. (c) The MR images of the nasopalatine duct cysts, which showed homogeneous high SI on T1WI, were specific. (d) The Gd-T1WI would be useful in decisively differentiating odontogenic cysts, which showed rim-enhancement, from tumors consisting of solid components. In conclusion, we were able to obtain more information from the MR and contrast enhanced MR images than from conventional radiograph findings.
European Journal of Radiology | 2001
Junichi Asaumi; Hironobu Konouchi; Miki Hisatomi; Kanji Kishi
We showed the characteristic features of odontogenic myxoma in the maxillary sinus with computed tomography (CT), magnetic resonance imaging (MRI), and histopathological findings. CT images showed a multilocular soft tissue mass with bone destruction and thinning, and the characteristic finding of this lesion as strands of fine lacelike density. MRI revealed intermediate signal intensity on T1-weighted image and high signal intensity on T2-weighted image. MRI showed the erosive extent of the lesion into the adjacent structures. In contrast T1-weighted image, the peripheral portion of the lesion with a relatively large quantity of collagen bundles was enhanced, while the central portion with only mucoid component was not. The CT and MRI appearances correlated well with the histologic features and therefore were considered to be a useful tool for diagnosis of myxoma.
European Journal of Radiology | 2003
Jun Ichi Asaumi; Yoshinobu Yanagi; Miki Hisatomi; Hidenobu Matsuzaki; Hironobu Konouchi; Kanji Kishi
In this study, we attempted to diagnose malignant lymphoma on the basis of magnetic resonance imagings (MRIs) and dynamic contrast-enhanced MRI (DCE-MRI). Eighteen lesions (in eight patients), all of which had been proven histopathologically, were detected on MRI. The eight patients included five patients with diffuse large B-cell lymphoma, one with B-cell low-grade MALT lymphoma, one with follicular lymphoma, and one with Hodgkins lymphoma. Nine lesions were located in the submandibular region, three in the buccal region, two in the orbit region, two in the submental region, and one each in the palatal and tonsil regions. The diameter of the lesions ranged between 9 and 42.2 mm (average: 22.4 mm). The signal intensities (SIs) of the 18 lesions were examined on T1-weighted (T1WI), T2WI, and gadopentetate (Gd)-T1WI. One lesion in case 8 was excluded from DCE-MRI findings, i.e., the regions of interest could not be adequately set on DCE-MRIs. The contrast index (CI) curves of the remaining 17 lesions were prepared. All 18 lesions showed almost the same images on T1WI, T2WI, and Gd-T1WI, although they represented four types of lymphoma. The images showed homogeneous SI that was intermediate to slightly high SI on T1WI, slightly high SI on T2WI, and moderately enhanced on Gd-T1WI. Thus, the cases of malignant lymphoma in this study showed relatively characteristic features based on MRI; however, these features might be non-specific. The CI curves in this study showed a relatively rapid increase, reaching a maximum CI at 45-120 s, and a relatively rapid decrease in most lesions (14/17; 82.4%); on the other hand, the curves of 3 of the 15 lesions (17.6%) showed relatively rapid increase, sustenance of a plateau, and a gradual decrease thereafter. These patterns of CI curves may indicate characteristic features useful for distinguishing malignant lymphomas from other lesions.
Oral Oncology | 2002
Miki Hisatomi; Jun Ichi Asaumi; Hironobu Konouchi; Yoshinobu Yanagi; Hidenobu Matsuzaki; Kanji Kishi
We examined three patients with multiple synchronous Warthins tumors in the bilateral parotid and described the value of using dynamic MRI. The time course of the contrast index (CI curves) was calculated from a dynamic series. Warthins tumors showed intermediate signal intensity on T1WI, heterogeneous high and intermediate signal intensity on T2WI and a slight enhancement on Gd-T1WI. Warthins tumors of CI curves showed specific findings. CI curves in each lesion showed the same pattern. It was difficult to diagnose masses as Warthins tumors using only MR images on T1, T2 and Gd-T1WI. Dynamic MRI can distinguish Warthins tumors from other possible tumors except for oncocytoma. Therefore, the use of dynamic MRI is recommended as a diagnostic method for Warthins tumors in multiple synchronous lesions of the parotid gland.
Oral Oncology | 2003
Hironobu Konouchi; Jun Ichi Asaumi; Yoshinobu Yanagi; Hiroshi Shigehara; Miki Hisatomi; Hidenobu Matsuzaki; Kanji Kishi
We investigated the relationship between the enhanced patterns acquired by dynamic MRI and the tumor cell proliferation estimated by immunostaining proliferating cell nuclear antigen (PCNA) in oral squamous cell carcinoma (SCC). Thirty patients with primary oral SCC underwent dynamic contrast enhanced (DCE)-MRI using a three-dimensional fast imaging with steady-state precession sequence. Tumor cell proliferation of all surgical specimens was evaluated using immunohistochemical staining with the anti-PCNA antibody. The relationship between the dynamic MRI parameters (maximum CI and maximum CI gain) and the PCNA labeling index was statistically analyzed using regression analysis. The time contrast index curves of all cases showed a rapid and high uptake pattern. The PCNA labeling index showed a significant correlation with maximum CI and maximum CI gain (P<0.0001, r=0.866 and P=0.0019, r=0.544, respectively). The assessment of DCE-MRI parameters may provide valuable information for tumor cell proliferation of the patients with oral cancer.
European Journal of Radiology | 2002
Hironobu Konouchi; Jun Ichi Asaumi; Yoshinobu Yanagi; Miki Hisatomi; Kanji Kishi
Adenomatoid odontogenic tumor is a rare benign and odontogenic tumor that is frequently misdiagnosed as other odontogenic cysts and tumors on radiographic examination. To acquire additional information of adenomatoid odontogenic tumor, we performed magnetic resonance imagings (MRI) at a case of adenomatoid odontogenic tumor. The lesion was divided between the peripheral portion with a thick circular shape and the central portion with a round shape on the basis of the signal intensity (SI) of MRI. The peripheral portion showed intermediate SI contained multifocal no SI on T1WI, high SI contained multifocal no SI on T2WI, and heterogeneous enhancement on CE-T1WI. These multifocal areas corresponded to the numerous punctate radiopaque foci shown on computed tomography. The central portion showed homogeneous low SI on T1WI, homogeneous very high SI on T2WI, and no enhancement on CE-T1WI. Macroscopic examination revealed the round shaped lesion included one large cystic space correspondent to the central portion with a clear cystic wall correspondent to the peripheral portion on MRI. The MRI features corresponded to the macroscopic findings of the histopathological examination.
European Journal of Radiology | 2002
Jun Ichi Asaumi; Hidenobu Matsuzaki; Miki Hisatomi; Hironobu Konouchi; Hiroshi Shigehara; Kanji Kishi
It is often difficult to radiographically distinguish odontogenic myxomas from ameloblastomas. In the present study, we tried to differentiate odontogenic myxomas from ameloblastomas using dynamic magnetic resonance imaging (dynamic MRI). Two cases of ameloblastoma with cystic components and two cases of odontogenic myxoma were compared by dynamic MRI. The dynamic MRI features of solid areas of ameloblastomas showed a rapid enhancement, reaching maximum contrast at 45-60 s, and maintained these enhancement levels or showed a gradual wash-out to 600 s thereafter; in contrast, those of the cystic areas of ameloblastomas showed no enhancement. The dynamic MRI features of the whole area of odontogenic myxomas (we considered the whole area to be the tumor substance in the odontogenic myxomas, as based on histopathological examinations) showed a gradual increase in enhancement at 500-600 s. The central portions of the odontogenic myxomas, which did not appear to be enhanced on Gd-T1 weighted images also showed a gradual increase in enhancement at 500-600 s, though the increase was minimal. These results indicate that the dynamic MRI features of odontogenic myxomas are different from those of ameloblastomas. Therefore, dynamic MRI may be a useful tool for diagnosis of myxoma.
Oral Oncology | 2003
Miki Hisatomi; Jun Ichi Asaumi; Yoshinobu Yanagi; Hironobu Konouchi; Hidenobu Matsuzaki; Yasutoshi Honda; Kanji Kishi
We evaluated magnetic resonance images (MRI) and the value of dynamic contrast enhanced MRI (DCE-MRI) of pleomorphic adenomas retrospectively. MRI was performed for 18 pleomorphic adenomas, including 11 cases with DCE-MRI. We obtained the following results on the MRI and DCE-MRI. (a). Pleomorphic adenomas showed a predilection for homogeneous intermediate signal intensity on T1-weighted images (T1WI), heterogeneous high signal intensity on T2-weighted images, and heterogeneous enhancement on Gd-T1WI. (b). Of 11 contrast index (CI) curves of pleomorphic adenomas, nine CI curves (81.8%) increased gradually to 600 s or increased gradually, reached a plateau, and sustained the plateau to 600 s. The remaining two (18.2%) increased gradually and decreased gradually thereafter. (c). CI curves reached the maximum CI index at 135-300 s.
European Journal of Radiology | 2001
Miki Hisatomi; Junichi Asaumi; Hironobu Konouchi; Hidenobu Matsuzaki; Kanji Kishi
We describe the magnetic resonance (MR) features of two cases of nasopalatine duct cyst (NPDC), including the first presentation of T1-weighted images (WI). The signal intensity of the cases of NPDC showed homogeneous high signal intensity on both on T1 and T2WI, although most cysts of maxillofacial regions demonstrate low to intermediate signal intensity on T1WI. NPDC may commonly be of high signal intensity on T1WI, which is consistent with keratin and viscous fluids.
Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology | 2010
Yoshinobu Yanagi; Jun Ichi Asaumi; Teruhisa Unetsubo; Masakazu Ashida; Toshihiko Takenobu; Miki Hisatomi; Hidenobu Matsuzaki; Hironobu Konouchi; Naoki Katase; Hitoshi Nagatsuka
INTRODUCTION It can be difficult to differentiate simple bone cysts (SBCs) from true cysts in the jaw when these lesions appear unilocular. The present study reports the MR imaging of subjects with SBCs and describes the diagnostic value of the MRI findings. MATERIALS AND METHODS Ten subjects with SBCs in the jaw were examined using MRI. T1- and T2-weighted images (T1WI, T2WI) were obtained, and contrast-enhanced images and dynamic contrast-enhanced MRI (DCE-MRI) were acquired. RESULTS In all cases, the contrast-enhanced T1WI acquired approximately 6 minutes after the administration of Gd-DTPA showed marked enhancement of the margin and slight enhancement of the inner part of the cyst cavity. In all cases, the time-signal intensity (SI) curves show a gradual increase in the SI until approximately 15 minutes after the administration of Gd-DTPA. These findings might not be observed on the DCE-MRIs of the other true cysts with epithelial lining that show no enhancement in a cavity. CONCLUSION MRI, especially DCE-MRI, can provide useful information for distinguishing SBCs from other cysts.