Biomedical subjects

Akiko Yagi

Publications and source records attributed to Akiko Yagi.

7 recordsLinked to original sources

PubMed2006

MR signal of the solid portion of pilocytic astrocytoma on T2-weighted images: is it useful for differentiation from medulloblastoma?

BACKGROUND AND PURPOSE: Although imaging features of cerebellar pilocytic astrocytoma and medulloblastoma have been described in many texts, original comparisons of magnetic resonance intensity between these two tumours are limited. In the present study the results of magnetic resonance imaging (MRI) were reviewed, focusing especially on the signal intensity of the solid portion of these neoplasms. METHODS: MR images of ten cerebellar pilocytic astrocytomas and ten medulloblastomas were reviewed. The signal intensities of the solid components were graded on a scale of 1 to 5, with higher scores indicating a signal intensity closer to that of water. The degree of enhancement, tumour cysts and peripheral oedema were evaluated on MR images. When the solid portion was heterogeneous (i.e. mixed signal intensity or degree of enhancement), the dominant area was selected for evaluation. RESULTS: On T2-weighted images, the signal intensity of the solid portion was equal to that of cerebrospinal fluid (CSF) in 50% of pilocytic astrocytomas. No medulloblastomas showed such hyperintensity. Most medulloblastomas (80%) were isointense to grey matter. On T1-weighted images, the signal intensity varied widely in pilocytic astrocytomas; however, all medulloblastomas were iso- or hypointense to grey matter. The MR enhancement pattern, cystic component and peripheral oedema all varied in both tumour types and no specific features were identified. CONCLUSION: A signal intensity of the solid portion isointense to CSF on T2-weighted images was characteristic of cerebellar pilocytic astrocytomas; this was not observed in medulloblastomas. Attention to T2-weighted imaging of the solid portions of a tumour is easy and helpful in differentiating between cerebellar pilocytic astrocytoma and medulloblastoma.

Adolescent↗

PubMed2005

Successful pregnancy and delivery after transfer of a single blastocyst derived from a vitrified mature human oocyte.

OBJECTIVE: To describe the first case of delivery after the transfer of a single blastocyst derived from a vitrified mature human oocyte. DESIGN: Case report. SETTING: Private assisted reproduction clinic. PATIENT(S): A normal 31-year-old woman. INTERVENTION(S): An unsuccessful attempt was made to extract sperm from the patient's nonobstructive azoospermic husband by testicular sperm extraction. MAIN OUTCOME MEASURE(S): Transfer of single blastocyst derived from vitrified human oocyte and donor sperm. RESULT(S): A healthy male neonate weighing 3000 g was born. CONCLUSION(S): Vitrification is a useful method of preserving mature human oocytes and has the advantage of time-effectiveness, simplicity, cost reduction, and no need for devices such as programmable freezers.

Adult↗

PubMed2005

Normal cranial nerves in the cavernous sinuses: contrast-enhanced three-dimensional constructive interference in the steady state MR imaging.

BACKGROUND AND PURPOSE: Three-dimensional (3D) constructive interference in steady state (CISS) MR imaging is useful for demonstrating cranial nerves (CNs) in the cistern. The purpose of this study was to evaluate normal CNs III, IV, V1, V2, and VI in the cavernous sinuses by using contrast-enhanced, three-dimensional (3D), Fourier transformation CISS MR imaging. METHODS: In 76 normal cavernous sinuses from 38 patients, detectability of CNs III-VI in the bilateral cavernous sinuses was evaluated by using contrast-enhanced 3D CISS MR imaging. In 40 cavernous sinuses from 20 patients, contrast-enhanced 3D CISS and contrast-enhanced T1-weighted MR imaging were compared for the detectability of these CNs. RESULTS: Each CN was separately demonstrated, and in 11 patients (29%), all CNs in the cavernous sinuses were identified on contrast-enhanced 3D CISS MR imaging. The images depicted the intracavernous segments of CNs III, IV, V1, V2, and VI in 76 (100%), 46 (61%), 70 (92%), 67 (88%), and 73 (96%) of the 76 sinuses, respectively. In comparison of imaging techniques, contrast-enhanced 3D CISS MR imaging had a detection rate significantly higher than that of enhanced T1-weighting imaging (P < .05) in all CNs except for CN III, which was detected in 100% of cases with both techniques. CONCLUSION: Contrast-enhanced 3D CISS MR imaging provides clear images of each CN in the cavernous segment. This useful method may contribute to the diagnosis of diseases involving the cavernous sinuses, such as Tolosa-Hunt syndrome.

Adolescent↗

PubMed2005

Clinical background and its relation to results of percutaneous needle biopsy of suspected bone metastasis under guidance with CT fluoroscopy.

PURPOSE: To investigate the clinical background of needle biopsy of suspected bone metastasis under guidance with CT fluoroscopy. PATIENTS AND METHODS: During a 3-year period (from April 2000 to March 2003), 103 needle biopsies on 101 lesions of 90 patients were performed for pathological evaluation of suspected bone metastasis. The clinical course of these patients prior to biopsy and its relation to the biopsy results were retrospectively reviewed. RESULTS: Sixty-two patients (69% of total cases) were referred for biopsy from orthopedic surgeons, and 51 of these patients consulted orthopedic surgeons on the initial presentation. Malignancy was pathologically proved in 47 (76%) of the 62 orthopedic patients, and in 19 (68%) of the 28 patients referred from other clinicians. Thirteen (21%) of the orthopedic patients had a history of malignancy, while 22 (78%) of the non-orthopedic patients were cancer patients. Metastasis was pathologically proved in 23 (66%) of the 35 patients with a history of malignancy, while malignancy was pathologically proved in 43 (78%) of the 55 patients without known malignancy. Diagnostic accuracy of the needle bone biopsy was 96%, and its complication rate was 0.7%. CONCLUSION: In the era of CT fluoroscopy, needle biopsy for suspected bone metastasis was most frequently requested for the patients who consulted orthopedic surgeons for the occurrence of local bone pain as the initial symptom of unknown malignancy. Frequency of malignancy proved by the biopsy in those patients was as high as that in the cancer patients referred from other clinicians.

Adolescent↗

PubMed2004

Freezing of human immature oocytes using cryoloops with Taxol in the vitrification solution.

PURPOSE: In human frozen immature oocytes, there has been little successful delivery. We examined the feasibility of vitrification solution including Taxol, cytoskeltal stabilizer. METHODS: We set four experimental groups that immature oocytes has cumulus cells or not, or including Taxol or not in the vitrification solution. Frozen-thawed oocytes have been performed IVM, ICSI, and IVC. RESULTS: There were no significant differences in survival, maturation, and fertilization rate, respectively. However, in the group enveloped by cumulus cells and including Taxol in the vitrification solution, one embryo was developed to blastocyst. CONCLUSIONS: Our results showed that using vitrification solution with Taxol proved so effective.

Blastocyst↗

PubMed2004

Successful pregnancy and delivery following combined treatment of in vitro maturation (IVM) and testicular sperm extraction (TESE): a case report.

PURPOSE: To report the efficacy of the combined treatment of in vitro maturation (IVM) and testicular sperm extraction (TESE). METHODS: A couple in which the wife had polycystic ovarian syndrome and the husband had severe oligozoospermia. Oocytes were cultured in vitro for maturation followed by oocytes pickup with natural cycle, and TESE was undergone for husband. Matured oocytes were fertilized by intracytoplasmic sperm injection, and two embryos were transferred to wife's uterine. RESULTS: This case was achieved during pregnancy and delivery of a healthy female infant. CONCLUSIONS: The combined treatment of IVM and TESE was effective for this couple's specific infertility factors.

Adult↗

PubMed2004

Pulmonary thromboembolism. Evaluating the indication and effect of a vena caval filter with indium-111-platelet scintigraphy.

A 63-year-old woman complained of chest pain and was referred to hospital where she was found to have left pleural effusion and swelling, local heat and edema of the right lower leg. Initial pulmonary perfusion scintigraphy demonstrated multiple defects and pulmonary thromboembolism (PTE) was confirmed during the anticoagulant and thrombolytic therapy against thrombophlebitis. A Greenfield filter was inserted in the inferior vena cava to prevent recurrence of PTE from the thrombosis that was resistant to therapy. In-111-labeled platelet scintigraphy (platelet scintigraphy) showed abnormal uptake of platelets in the chest, femoral veins and abdomen, which suggested active thrombus formation in those regions, including the filter, and a risk of recurrent PTE. Therefore, the thrombolytic therapy was terminated and the anticoagulant therapy intensified. A computed tomography (CT) scan revealed thrombus at the filter, which was markedly decreased 1 month later on platelet scintigraphy. Pulmonary ventilation and perfusion scintigraphy revealed remarkable improvement of the PTE. In this case, platelet scintigraphy complemented CT in demonstrating the activity and localization of the thrombus and can be used to evaluate the risk of recurrence during thrombolytic therapy after insertion of a filter.

Blood Platelets↗