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Biomedical subjects

Shuji Sakai

Publications and source records attributed to Shuji Sakai.

At least 19 recordsLinked to original sources
PubMed2006

Detection of masses and microcalcifications of breast cancer on digital mammograms: comparison among hard-copy film, 3-megapixel liquid crystal display (LCD) monitors and 5-megapixel LCD monitors: an observer performance study.

The purpose of the study was to compare observer performance in the detection of masses and microcalcifications of breast cancer among hard-copy reading and soft-copy readings using 3-megapixel (3M) and 5-megapixel (5M) liquid crystal display (LCD) monitors. For the microcalcification detection test, we prepared 100 mammograms: 40 surgically verified cancer cases and 60 normal cases. For the mass detection test, we prepared 100 mammograms: 50 cancer cases and 50 normal cases. After six readers assessed both microcalcifications and masses set for each modality, receiver operating characteristic (ROC) analysis was performed. The average A(z)s for mass detection using a hard copy and 3M and 5M LCD monitors were 0.923, 0.927 and 0.920, respectively; there were no significant differences. The average A(z) for microcalcification detection using hard copy, 3M and 5M LCD monitors was 0.977, 0.954 and 0.972, respectively. There were no significant differences, but the P-values between the hard copy and 3M LCD monitor and that between the 3M and 5M LCD monitor were 0.08 and 0.09, respectively. In conclusion, the observer performances for detecting masses of breast cancers were comparable among the hard copy and two LCD monitors; however, soft-copy reading with a 3M LCD monitor showed slightly lower observer performance for detecting microcalcifications of breast cancers than hard-copy or 5M LCD monitor reading.

Adult↗
PubMed2006

Phyllodes tumor of the breast: correlation between MR findings and histologic grade.

PURPOSE: To retrospectively evaluate the magnetic resonance (MR) imaging findings of phyllodes tumor of the breast and to compare these findings with the histologic grade. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. The authors reviewed the MR findings in 30 female patients aged 16-73 years (mean, 40.2 years) with surgically confirmed phyllodes tumors. Analyzed MR findings included tumor shape, margin, internal enhancement, and size; signal intensity (SI) of tumor higher than that of normal breast tissue on T1-weighted images; SI of tumor lower than or equal to that of normal tissue on T2-weighted images; cyst wall appearance; kinetic curve assessment; and apparent diffusion coefficient (ADC). The MR findings and histologic grade were statistically analyzed to determine whether any correlations existed. Significant MR findings were compared with histopathologic findings. RESULTS: Nineteen benign, six intermediate (characterized by five to nine cell reproductions at 10 high-power fields, pushing or infiltrative margins, moderate stromal cellularity, and atypia and overgrowth), and five malignant phyllodes tumors were assessed. Irregular cyst wall (P = .003), tumor SI lower than or equal to normal tissue SI on T2-weighted images (P = .005), and low ADC (P = .001) correlated significantly with histologic grade. Tumor SI higher than normal tissue SI on T1-weighted images was more frequent in the malignant (in three of five tumors) and intermediate (in three of six tumors) groups than in the benign group (in two of 19 tumors); however, it was not a significant finding (P = .024). Tumor SI higher than normal tissue SI on T1-weighted images and irregular cyst wall corresponded histopathologically to hemorrhagic infarction and necrosis, respectively. Tumor SI lower than or equal to normal tissue SI on T2-weighted images and low ADC corresponded histopathologically to stromal hypercellularity. Other findings were not significant. CONCLUSION: Several MR findings can be used to help determine the histologic grade of phyllodes breast tumors.

Adolescent↗
PubMed2006

MR imaging features of pure mucinous carcinoma of the breast.

OBJECTIVE: To characterize MR imaging features of pure mucinous carcinoma of the breast. MATERIALS AND METHODS: MR images obtained from 16 women (age range, 29-81; mean age, 57 years) with pure mucinous carcinoma of the breast determined at surgery were reviewed. The MR findings used were shape, margin, internal mass enhancement, kinetic curve pattern on dynamic study, signal intensity on short time inversion recovery (STIR) T2-weighted images, and non-mass-like enhancement around the main tumor. Non-mass-like enhancement was compared with the presence of extensive intraductal component (EIC) on histopathological findings. RESULTS: Eleven tumors (69%) had lobular contour, and nine tumors (56%) had smooth margin. Eight tumors (50%) showed rim enhancement and six tumors (38%) showed heterogeneous enhancement. Fourteen tumors (88%) showed a persistent enhancing pattern on kinetic curve. Fifteen tumors exhibited homogenous strongly high signal intensity on STIR T2-weighted images. In six cases with EIC, five cases had non-mass-like enhancement around the main mass. CONCLUSIONS: MR findings such as lobular shape, rim or heterogeneous enhancement, persistent pattern on kinetic curve, and homogeneous strongly high signal intensity on STIR T2-weighted images may be useful in diagnosing pure mucinous carcinoma. Moreover, linear-ductal enhancement around main mass may indicate presence of EIC.

Adenocarcinoma, Mucinous↗
PubMed2006

Evaluation of the image quality of temporal subtraction images produced automatically in a PACS environment.

The aim of the study is to evaluate the reliable production of temporal subtraction images in a picture archiving and communication system environment and to establish objective criteria for the evaluation of image quality. A total of 117 temporal subtraction chest images (55 in the upright position, 62 in the supine position) were obtained in five consecutive days. In all of these, we confirmed that there were no interval changes on the original images, and cases with diffuse lung disease were excluded. The temporal subtraction images were classified by three chest radiologists into five levels: 5, excellent; 4, good; 3, acceptable; 2, poor; and 1, very poor. The following were examined: (1) the yield of adequate quality of the temporal subtraction images; (2) whether the temporal subtraction images were obtained in the warping or nonwarping mode; and (3) the correlation of the overall subjective image quality with the relative shift angles, relative shift distances, and the standard deviation of gray levels in the temporal subtraction images. The percentages of acceptable temporal subtraction images were 100% and 66% in the upright and supine positions, respectively. Sixteen (26%) of the 62 supine-position images were made in nonwarping mode, whereas all upright images were made in warping mode. Significant correlations were obtained in the relative shift angle (P < 0.05), relative horizontal shift distance (P < 0.05), and standard deviation of gray levels (P < 0.0001). Temporal subtraction images with acceptable image quality were obtained in the upright position. The objective criteria may be useful for the evaluation of image quality.

Humans↗
PubMed2006

Computer-aided nodule detection on digital chest radiography: validation test on consecutive T1 cases of resectable lung cancer.

PURPOSE: To evaluate the usefulness of a commercially available computer-assisted diagnosis (CAD) system on operable T1 cases of lung cancer by use of digital chest radiography equipment. MATERIALS AND METHODS: Fifty consecutive patients underwent surgery for primary lung cancer, and 50 normal cases were selected. All cancer cases were histopathologically confirmed T1 cases. All normal individuals were selected on the basis of chest computed tomography (CT) confirmation and were matched with cancer cases in terms of age and gender distributions. All chest radiographs were obtained with one computed radiography or two flat-panel detector systems. Eight radiologists (four chest radiologists and four residents) participated in observer tests and interpreted soft copy images by using an exclusive display system without and with CAD output. When radiologists diagnosed cases as positives, the locations of lesions were recorded on hard copies. The observers' performance was evaluated by receiver operating characteristic analysis. RESULTS: The overall detectability of lung cancer cases with CAD system was 74% (37/50), and the false-positive rate was 2.28 (114/50) false positives per case for normal cases. The mean A(z) value increased significantly from 0.896 without CAD output to 0.923 with CAD output (P = 0.018). The main cause of the improvement in performance is attributable to changes from false negatives without CAD to true positives with CAD (19/31, 61%). Moreover, improvement in the location of the tumor was observed in 1.5 cases, on average, for radiology residents. CONCLUSION: This CAD system for digital chest radiographs is useful in assisting radiologists in the detection of early resectable lung cancer.

Adult↗
PubMed2006

Pulmonary lesions associated with visceral larva migrans due to Ascaris suum or Toxocara canis: imaging of six cases.

OBJECTIVE: The objective of our study was to evaluate chest radiographic and CT findings of patients with pulmonary lesions associated with visceral larva migrans due to Ascaris suum or Toxocara canis. CT investigation was focused on the location, size, contour, and internal features of the lesions; migration of lesions; mediastinal lymphadenopathy; and pleural effusion. CONCLUSION: Pulmonary visceral larva migrans appears on CT as multifocal subpleural nodules with halo or ground-glass opacities and ill-defined margins.

Adult↗
PubMed2005

Correlation of mandibular deviation with temporomandibular joint MR dimensions, MR disk position, and clinical symptoms.

OBJECTIVE: The objective of this study was to investigate the difference of the temporomandibular joint (TMJ) between deviated and nondeviated sides of the mandible in adult patients with mandibular deviation. STUDY DESIGN: TMJ size, disk displacement, and clinical symptoms of 28 patients were examined clinically and by magnetic resonance imaging (MRI). Twelve age- and sex-matched control subjects were also used to evaluate which side of the mandible in patients was similar to the control. RESULTS: The TMJ on the deviated side showed a smaller condyle and a higher incidence of disk displacement than the nondeviated side and those in the controls. However, the clinical symptoms showed no differences between the deviated and nondeviated sides, and no association with disk displacement. CONCLUSIONS: Our results suggest that the deviated side was the abnormal side and may have some association with mandibular deviation. However, the clinical symptoms could not indicate those differences.

Adolescent↗
PubMed2005

Multifocal nodular lymphoid hyperplasia of the lung.

Nodular lymphoid hyperplasia (NLH) is one of the pulmonary lymphoproliferative disorders, and was initially described as pseudolymphoma. However, reports focusing on CT findings of NLH of the lung have been rare. We report a case of a pulmonary NLH in a 49-year-old woman who showed multiple pulmonary nodules on HRCT and was misdiagnosed preoperatively with adenocarcinoma on the basis of transthoracic cytology. A final diagnosis of NLH was made on postoperative histologic examination.

Female↗
PubMed2005

Gorham's disease of the chest wall: CT and MR characteristics.

We report a case of Gorham's disease of the chest wall in a 29-year-old man. A chest radiograph showed osteolysis of the left first, second, and third ribs. CT and MR images revealed a soft tissue mass around the affected ribs. The mass presented as having heterogeneous high signal intensity on T2-weighted MR images, and it showed minimal enhancement on contrast-enhanced MR images. A histologic specimen obtained by incisional biopsy from the left third rib revealed proliferation of lymphangiomatous tissue in the bone marrow. A diagnosis of Gorham's disease was made based on these clinical, radiologic, and histologic findings.

Adult↗
PubMed2004

[Bone quantity and quality to its mechanical integrity].

Bone strength is made up of quantity (mass, mineralization), geometry (anatomy, micro architecture, collagen structure), and turnover/damage accumulation. While most of the mechanical behavior can be explained by measures of porosity, several additional descriptors of the geometry have been proposed for better predictions of fracture risk. This review introduces various aspects of these relationships between bone quantity and quality to its mechanical integrity.

Biomechanical Phenomena↗
PubMed2003

Alterations of tumor suppressor genes (Rb, p16, p27 and p53) and an increased FDG uptake in lung cancer.

OBJECTIVE: The FDG uptake in lung cancer is considered to reflect the degree of malignancy, while alterations of some tumor suppressor genes are considered to be related to the malignant biological behavior of tumors. The aim of this study is to examine the relationship between FDG-PET and alterations in the tumor suppression genes of lung cancer. METHODS: We examined 28 patients with primary lung cancer who underwent FDG-PET before surgery consisting of 17 patients with adenocarcinoma, 10 with squamous cell carcinoma and 1 with large cell carcinoma. The FDG-PET findings were evaluated based on the standardized uptake value (SUV). Alterations in the tumor suppressor genes, Rb, p16, p27 and p53, were evaluated immunohistochemically. RESULTS: The FDG uptake in lung cancer with alteration in each tumor suppressor gene tended to be higher than in those genes without alterations, although the differences were not significant. In 15 tumors with alterations in either tumor suppressor genes, the FDG uptake was 6.83 +/- 3.21. On the other hand, the mean FDG uptake was 1.95 in 2 tumors without alterations in any genes. The difference in the FDG uptake between the 2 groups was statistically significant (p < 0.001). CONCLUSIONS: In conclusion, the presence of abnormalities in the tumor suppressor genes, which results in an accelerated cell proliferation, is thus considered to increase the FDG uptake in lung cancer.

Adult↗
PubMed2003

Lung cancer associated with diffuse pulmonary fibrosis: CT-pathologic correlation.

The authors reviewed the computed tomographic (CT) scans and pathologic specimens of 57 histologically proved bronchogenic carcinomas (35 squamous cell carcinomas, 12 small cell carcinomas, and 10 adenocarcinomas) in 47 patients with diffuse pulmonary fibrosis. The patients ranged in age from 61 to 87 years (mean age, 72 years; 42 men and 5 women). On radiography and CT, most tumors (82%) were located in peripheral areas of honeycomb lung. In 50 of the 57 lesions, the tumors were round or lobulated with sharp margins. In seven tumors, including six squamous cell carcinomas and one small cell carcinoma, the tumor invaded the adjacent honeycomb lung and lacked distinct margins. Intratumor lucency was seen in 13 tumors (five solitary and eight multiple). The CT findings, including high-resolution CT scans, were compared with the histologic findings in a subgroup of 29 lesions in 25 patients with available surgical or autopsy specimens. Invasive growth of tumors with unclear margins (four lesions), septal thickening of the contiguous/surrounding honeycombed areas (16 lesions), and discrete masses (nine lesions) with solitary (four of nine) or multiple (five of nine) intratumor lucencies. The lucencies in six of nine patients (67%) with intratumor lucencies were found to represent engulfed cystic airspaces histologically. CT revealed that bronchogenic carcinoma associated with diffuse pulmonary fibrosis has distinct morphologic characteristics that correlate histologically with a specific pattern of tumor growth.

Aged↗
PubMed2003

Comparison between the shape of resected femoral sections and femoral prostheses used in total knee arthroplasty in Japanese patients: simulation using three-dimensional computed tomography.

Simulation of the femoral cut for total knee arthroplasty was performed in 44 knees using three-dimensional computed tomography. The three-dimensional images were measured, and the shape of the femur was compared to the provided femoral prosthesis. The ratio between the medial-lateral and anteroposterior dimensions of the three-dimensional images did not always match the prosthesis. The widths of the medial condyles of the three-dimensional images tended to be larger than those of the prosthesis. The lengths of the lateral posterior condyles of the three-dimensional images tended to be shorter than those of the prosthesis. These results suggest that a new prosthesis should be designed to achieve a better anatomical fit.

Aged↗
PubMed2002

CD4-CD8- T-cell polymyositis in a patient with chronic active Epstein-Barr virus infection.

We describe a 17-year-old woman with chronic active Epstein-Barr virus infection (CAEBV), who developed EBV+CD4-CD8- T-cell polymyositis. At 14 years of age, CAEBV was diagnosed with fever, cytopenia, liver dysfunction, and hepatosplenomegaly. Despite the transient remission of interferon-alpha therapy, migratory lesions emerged in back and extremities. MRI indicated polymyositis. Biopsy specimens revealed intramuscular infiltration of CD3+, CD4-, CD8-, CD56-, and EBV-encoded RNA 1+ cells. Circulating CD4-CD8-Vdelta2/Vgamma9 cells increased. gammadeltaT-cells contained 20-200 times higher EBV-DNA (2 x 10(4) copies/microgDNA) than alphabetaT-cells or NK-cells. The ominous polymyositis might denote the musculotropic invasion of EBV+gammadeltaT-cell lymphoproliferative disease as a consequence of CAEBV.

Adolescent↗
PubMed2002

CT and MR features of nasopharyngeal carcinoma in children and young adults.

AIM: To clarify CT and MR features of nasopharyngeal carcinoma (NPC) in children and young adults. METHOD: CT and MR findings of 13 patients (30 years old or younger) with a histopathologic diagnosis of NPC were reviewed. RESULTS: Skull base invasion (12/13), lymphadenopathy (10/13), and infiltrative growth (8/8) were common findings. The signal intensity of tumours was slightly higher than that of muscles in six cases and isointense to that of muscles in two cases on T1-weighted images; it was higher than that of muscle and lower than that of cerebellar grey matter on T2-weighted images in all cases. Internal signals were homogeneous in both pre- and post-Gd-enhanced MR images in all cases. CONCLUSIONS: Despite its rarity in this age group, NPC should be included in a differential diagnosis when CT and MR imaging reveal these features.

Adolescent↗
PubMedDate not supplied

A case of pulmonary synovial sarcoma diagnosed with detection of chimera gene: imaging findings.

Pulmonary synovial sarcoma is a rare disease, and reports detailing clinicians' radiological findings are few. We report a case of a primary pulmonary synovial sarcoma in a 68-year-old woman. Chest CT revealed a well-defined and homogeneous oval mass measuring 3x2.5 cm in the left lower lobe in contact with the visceral pleura. No pleural effusion was evident. No calcification or fat component was detected. The tumor showed homogeneous hypointensity on both T1- and T2-weighted MR imaging. In this case, a lung metastasis could be excluded with fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), and the final diagnosis was histopathologically confirmed by the chimeric gene detection.

Aged↗
PubMedDate not supplied

Pulmonary cryptococcosis in immunocompetent patients: HRCT characteristics.

We analyzed the high-resolution CT (HRCT) findings of cryptococcosis in immunocompetent patients. The predominant manifestations were multiple nodules (n=6) and a single nodule (n=7). Regarding the pattern of multiple nodules, two cases of cavities or necrosis, four cases of surrounding centrilobular micronodules and five cases of "acinar" nodules were seen. No "tree-in-bud" appearance was detected. Five of seven cases of a single nodule were classified as polygonal, and two of them were round. Two cases accompanied micronodules and one case cavitation. Although no "tree-in-bud" appearance was observed, pulmonary cryptococcosis mimics tuberculosis.

Adult↗