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Biomedical subjects

Shigeru Ehara

Publications and source records attributed to Shigeru Ehara.

At least 37 records · Page 2Linked to original sources
PubMed2004

Noninvasive measurement of temperature and fractional dissociation of imidazole in human lower leg muscles using 1H-nuclear magnetic resonance spectroscopy.

The temperature change of the fractional dissociation of imidazole (alpha-imidazole) in resting human lower leg muscles was measured noninvasively using (1)H-nuclear magnetic resonance spectroscopy at 3.0 and 1.5 T on five normal male volunteers aged 30.6 +/- 10.4 yr (mean +/- SD). Using (1)H-nuclear magnetic resonance spectroscopy, water, carnosine, and creatine in the muscles could be simultaneously analyzed. Carnosine contains imidazole protons. The chemical shifts of water and carnosine imidazole protons relative to creatine could be used for estimating temperatures and alpha-imidazole, respectively. Using the chemical shift, the values of temperature in gastrocnemius (Gast) and soleus muscles at ambient temperature (21-25 degrees C) were estimated to be 35.5 +/- 0.5 and 37.4 +/- 0.6 degrees C (means +/- SE), respectively (significantly different; P < 0.01). The estimated values of alpha-imidazole in these muscles were 0.620 +/- 0.007 and 0.630 +/- 0.013 (means +/- SE), respectively (not significant). Alternation of the surface temperature of the lower leg from 40 to 10 degrees C significantly changed the temperature in Gast (P < 0.0001) from 38.1 +/- 0.5 to 28.0 +/- 1.2 degrees C, and the alpha-imidazole in Gast decreased from 0.631 +/- 0.003 to 0.580 +/- 0.011 (P < 0.05). However, the values of alpha-imidazole and the temperature in soleus muscles were not significantly affected by this maneuver. These results indicate that the alpha-imidazole in Gast changed significantly with alternation in muscle temperature (r = 0.877, P < 0.00001), and its change was estimated to be 0.0058/ degrees C.

Adult↗
PubMed2004

Rapid involution of proliferative fasciitis.

A process of evolution and involution is a characteristic feature of reactive fibrous lesions, but has not been emphasized in either the radiology or pathology literature. We report a case of proliferative fasciitis, pseudotumorous fibrous proliferation similar to nodular fasciitis, showing evolution and involution during a 1-month period. A 35-year-old Japanese woman presented with a tender soft tissue mass in the forearm that had grown over a 2-week period. MR imaging revealed a soft tissue mass of nonspecific signal intensity on the muscle fascia. Needle biopsy revealed diffuse proliferation of fibroblastic spindle cells representing proliferative fasciitis. Two weeks after biopsy the mass had rapidly decreased in size, and the pain subsided. MR imaging obtained 1 month later demonstrated only minimal residual reactive change along the fascia. Conservative treatment may be a reasonable treatment option for this condition.

Adult↗
PubMed2004

Bone scintigraphic and CT evaluation of chondrosarcoma of the rib: correlation with histological grade in 6 cases.

OBJECTIVE: The objective of this study is to assess the value of CT and bone scintigraphic findings for grading of rib chondrosarcoma. METHODS: Included in this study were six cases of histologically proven chondrosarcoma of the rib, in which bone scintigraphy and/or CT was performed. Correlation of histologic grade (I-III), tumor size on CT, CT grading (modified Brown's system), the pattern (nodular or peripheral, presence or absence of extended uptake pattern) and the intensity (Simon and Kirchner's grade, 0-4) of scintigraphic uptake were assessed. RESULTS: CT grade was III, except for one case of dedifferentiated chondrosarcoma. Scintigraphic grade was 3 or 4 in all the cases. CONCLUSION: The patterns of CT and bone scintigraphic findings more likely reflect the size of the mass and ossification, and are not well correlated with the histological grading.

Adult↗
PubMed2004

Substantia innominata: MR findings in Parkinson's disease.

To elucidate MR imaging changes of the substantia innominata in Parkinson's disease (PD), using a 1.5-T superconductive MR unit, the thickness of the substantia innominata was measured on coronal thin-section images in 44 PD patients and 20 age-matched control subjects. We also evaluated the correlation between the thickness of the substantia innominata and mental status in PD patients. Mean thickness of the substantia innominata was 2.3 mm in PD patients, and 2.5 mm in control subjects. Thinning of the substantia innominata was statistically significant in PD patients compared with control subjects, although there were large overlaps. Among the PD patients, thinning was remarkable in cases with dementia. A positive correlation between thickness of substantia innominata and score of Mini-Mental-Status-Examination was also observed in PD patients. Atrophy of the substantia innominata was demonstrated, especially in PD patients with cognitive impairment, on coronal MR images, and this is compatible with the previous pathological reports.

Adult↗
PubMed2004

Skeletal muscle metastases of carcinoma: a clinicopathological study of 12 cases.

OBJECTIVE: To clarify the clinical and magnetic resonance (MR) imaging features of a rare condition of metastasis of carcinoma to skeletal muscle. METHOD: Clinicopathological findings for 12 patients (10 male, two female, age range 48-89 years, mean age 68 years) with skeletal muscle metastases of carcinomas were reviewed retrospectively. RESULTS: In nine of the 12 patients the skeletal muscle metastasis was presented as "painful mass". The lung was found to be the most common primary source, accounting for 33% of the cases, and the lower extremity was the most common metastatic site, accounting for 67% of the current series. Diagnosis was made by biopsy in all cases. Overall, MR images were not specific, but on the gadolinium-DTPA enhanced MR images, extensive peritumoral enhancement associated with central necrosis was found in 11 of the 12 patients (92%). Seven patients died within 2-19 months (average: 9 months) after the detection of the skeletal muscle metastasis, among whom only one patient was continuously disease free for 92 months after wide excision of the metastatic lesion. CONCLUSION: Skeletal muscle metastasis is often presented as a painful mass in patients with known primary carcinoma. For diagnosis, needle biopsy is mandatory. However, a painful mass with an extensive peritumoral enhancement should be highly suspected to represent carcinoma metastasis to skeletal muscles. In selected patients, wide excision with combined chemotherapy could yield unexpectedly good results.

Aged↗
PubMed2003

High-field MRI of the central nervous system: current approaches to clinical and microscopic imaging.

Introduction of clinical high-field MRI has raised interest in the use of clinical imaging--the efficacy of which has not yet been fully established--in daily practice. A high signal-to-noise ratio and profound susceptibility effects can improve the spatial resolution and image contrast of clinical imaging, whereas the heating effects of the radio frequency tend to prolong acquisition time. As well, inhomogeneities in the static or local magnetic fields can have a negative effect on image quality. The T(1) prolongation may affect T(1) contrast yet improve the enhancement effect of gadolinium chelate and the inflow effect of MR angiography. High-contrast imaging, such as the short inversion-time inversion recovery technique, can provide excellent intra- and extracerebral contrast comparable to microscopic or macroscopic specimens. High-field systems can also be applied to microscopic imaging. High-field MRI is expected to have an increased clinical impact in the near future. Technological advances tailored to high-field systems, as well as the accumulation of scientific evidence, will be necessary to establish its predominance over conventional MRI.

Central Nervous System↗
PubMed2003

Tetraparesis caused by chondroblastoma of the cervical spine: a case report.

STUDY DESIGN: A chondroblastoma of the posterior component of the seventh cervical vertebra with tetraparesis was reported. Imaging studies showed an expansile destructive lesion with mineralization. OBJECTIVES: To emphasize the occurrence of tetraparesis caused by chondroblastoma in the cervical spine. SUMMARY OF BACKGROUND DATA: Chondroblastoma is a rare benign neoplasm of the bone. Only eight cases of chondroblastoma occurring in the vertebra are reported in the literature, including five in the cervical vertebrae. However, there was no reported case of tetraparesis in the literature. METHODS: A 19-year-old man had a tetraparesis caused by chondroblastoma of the posterior component of the seventh cervical vertebra, which invaded the vertebral body with an extraosseous involvement. Imaging studies showed an expansile destructive lesion with mineralization. Curettage of the lesion was performed from both anterior and posterior approaches. The defect of the vertebral body was reconstructed by autologous iliac bone graft with posterior fusion using the Luque instrumentation system. RESULTS: Histologically, the tumor cells were forming cartilage with round or oval nuclei, which often were indented or had a longitudinal groove. There was no sign of local recurrence, and the neurologic deficit had fully recovered 2 years and 3 months after surgery. CONCLUSIONS: Chondroblastoma should be included in the differential diagnosis of lytic expansile destructive lesion of the spine, although there is an extraosseous involvement. Prompt adequate surgery should be performed as soon as possible after establishment of the correct histologic diagnosis to restore the neurologic deficit.

Adult↗
PubMed2003

Magnetic resonance imaging features of epidermoid cyst in the extremities.

BACKGROUND: Epidermoid cyst is a common benign soft-tissue tumor that occurs in the skin. There have been very few descriptions about the magnetic resonance (MR) images of epidermoid cysts in the extremities. MR imaging findings of epidermoid cysts may be characteristic enough to make the preoperative diagnosis possible. The purpose of this paper is to elucidate the MR imaging features of epidermoid cysts arising in the limbs. METHODS: We evaluated the MR images of five patients with an epidermoid cyst in the limbs. MR imaging and other radiological examinations were evaluated. T1-weighted (T1W), T2-weighted (T2W), and Gd-enhanced T1W images were taken in all the patients. RESULTS: The size of the lesion ranged from 2 to 10 cm with an average of 5.2 cm. All the tumors were located in the subcutaneous tissue with a well-circumscribed margin. On T1W MR imaging, the tumor had a slightly high signal intensity in three out of five cases and iso-signal intensity in the remaining two cases. On T2W images, they all showed high signal intensity. Irregular low signal intensity areas were noted in the tumors on both T1W and T2W images. No enhancement was observed inside the tumors. CONCLUSION: Subcutaneous tumor location, well-circumscribed margin, and isosignal to slightly high signal intensity with some heterogeneity on T1W MR images and high signal intensity T2W MR images, and no enhancement are useful features for a diagnosis of epidermoid cyst of the extremity.

Adult↗
PubMed2003

Iridium-192 brachytherapy for hemorrhagic angiosarcoma of the scalp: a case report.

A 60-year-old woman presented with multicentric skin tumors of the head. The histologically proven hemangioendothelioma was bleeding as a result of disseminated coagulopathy. In addition to immunotherapy, 6 MeV electron beam radiotherapy was used for the purpose of hemostasis with a single portal, 20 x 20 cm in size, covering the whole scalp from the top of the head. The radiotherapy was discontinued after 39 Gy/13 fractions/20 days because of the progress in size of a peripheral tumor and the stability of coagulopathy. After another electron boost delivery by two portals focused to exophytic parietal and temporal tumors of 20 Gy/10 fractions, high dose rate brachytherapy with a surface mold technique was performed, 3 Gy/fraction, four fractions/week, for a total of 36 Gy. It induced partial regression of the tumor and complete recovery of platelet counts from 2.5 x 10(4) to 18.2 x 10(4). The tumor disappeared in 3 months. No late side effects occurred, except for permanent alopecia. The patient developed a cervical lymph node metastasis 1 year after and marginal recurrence 2 years after the initial treatment. Both recurrent tumors were successfully treated by 4 MV external photons of 60 Gy/20 fractions/46 days and electron beam irradiation of 60 Gy/20 fractions/29 days, respectively. She has remained disease free for 3 years after the initial presentation.

Brachytherapy↗
PubMed2003

Radiologically and histologically mixed liposarcoma: a report of two biphasic cases.

We report two cases of liposarcomas showing biphasic patterns, radiologically and histologically. The first case was a 52-year-old man with a 17 x 12 cm intramuscular tumor in the right thigh. MR imaging revealed a mass composed of two components: a fat component and another soft tissue component. Histological diagnosis revealed mixed-type liposarcoma consisting of well-differentiated and myxoid liposarcoma. The second case was a 62-year-old man with a 22 x 15 cm intramuscular tumor in the left calf. MR imaging showed a mass composed of fat and non-fat components. The histological diagnosis was well-differentiated and pleomorphic liposarcoma.

Diagnosis, Differential↗
PubMed2002

Leiomyosarcoma of the lumbar spine: case report.

STUDY DESIGN: A primary leiomyosarcoma in the L2 vertebral body without any neurologic deficit is reported. The radiologic diagnosis was a metastasis, and the histologic diagnosis was confirmed by transpedicular needle biopsy. OBJECTIVE: To emphasize the occurrence of primary leiomyosarcoma in the lumbar spine. SUMMARY OF BACKGROUND DATA: Leiomyosarcoma is a rare malignant neoplasm of the bone, and only one report of the primary spinal tumor exists. In the case of leiomyosarcoma of the bone, metastasis, most commonly of the uterus or gastrointestinal tract, must be carefully ruled out before the diagnosis of primary leiomyosarcoma in the bone is confirmed. METHODS: Leiomyosarcoma of the second lumbar vertebra in a 47-year-old woman with no neurologic deficit is reported. Imaging findings indicated a nonspecific high-grade lesion. A total spondylectomy of L2 with en bloc excision of the lower half of L1 and the upper third of L3 vertebral bodies was performed after preoperative radiation therapy. The defect of the vertebral body was reconstructed by titanium mesh cage, and T11 to S1 vertebrae were instrumented by the pedicle screw and rod system. RESULTS: The surgical margin was marginal. Histologically, the tumor cells were elongated, with abundant cytoplasm and cigar-shaped nuclei, showing proliferation in fascicles and bundles. No sign of local recurrence or metastasis was evident 2 years and 1 month after surgery. CONCLUSIONS: Leiomyosarcoma should be included in the differential diagnosis of spindle cell tumor of the spine, and it should be confirmed or excluded by immunohistochemical and/or ultrastructural studies. If the expected surgical margin is definitive, a total en bloc spondylectomy should be performed.

Diagnosis, Differential↗