Yeu-Sheng Tyan

Survey of computed tomography scanners in Taiwan: Dose descriptors, dose guidance levels, and effective doses

The IAEA and the ICRP recommended dose guidance levels for the most frequent computed tomography (CT) examinations to promote strategies for the optimization of radiation dose to CT patients. A national survey, including on-site measurements and questionnaires, was conducted in Taiwan in order to establish dose guidance levels and evaluate effective doses for CT. The beam quality and output and the phantom doses were measured for nine representative CT scanners. Questionnaire forms were completed by respondents from facilities of 146 CT scanners out of 285 total scanners. Information on patient, procedure, scanner, and technique for the head and body examinations was provided. The weighted computed tomography dose index (CTDI(w)), the dose length product (DLP), organ doses and effective dose were calculated using measured data, questionnaire information and Monte Carlo simulation results. A cost-effective analysis was applied to derive the dose guidance levels on CTDI(w) and DLP for several CT examinations. The mean effective dose +/- standard deviation distributes from 1.6 +/- 0.9 mSv for the routine head examination to 13 +/- 11 mSv for the examination of liver, spleen, and pancreas. The surveyed results and the dose guidance levels were provided to the national authorities to develop quality control standards and protocols for CT examinations.

Emergency management of epidural haematoma through burr hole evacuation and drainage. A preliminary report

SummaryBackground. Blood clot evacuation through an osteoplastic craniotomy, a procedure requiring neurosurgical expertise and modern medical facilities, is the accepted method for treatment of a pure traumatic epidural haematoma following closed head injury. In certain emergency situations and/or in less sophisticated settings, however, use of this procedure may not be feasible. The present study was undertaken to ascertain whether placement of a burr hole and drainage under negative pressure constituted a rapid, effective and safe approach to manage patients with simple epidural haematomas.Methods. Thirteen patients suffering from a traumatic epidural haematoma were treated from January, 1999 to October, 2002. Twelve patients presented with skull fracture but no fracture was depressed. Placement of flexible tubes through a burr hole, followed by continuous suction under negative pressure, enabled aspiration of the clot and drainage of the cavity. In 8 cases, the procedure was performed under local anaesthesia with 2% Xylocaine™ and with intravenous sedation with propofol as needed. The operative procedure was accomplished within 30 min, and the drainage tube was left in place for 3–5 days. CT scans were performed daily from days 1 to 5.Results. In 11 of 13 cases, clots were evacuated successfully and patients regained consciousness within 2 hours. Recoveries occurred without significant sequelae. In the remaining 2 cases, the drainage tube was found to be obstructed by a blood clot such that the haematoma was unaffected. A traditional craniotomy was performed within 8–12 hours, and these 2 patients recovered consciousness within the subsequent 6 hours.Conclusion. Burr hole evacuation followed by drainage under negative pressure is a safe and effective method for emergency management of a pure traumatic epidural haematoma. To assure safety patients given this procedure should be monitored by daily CT scans. Decompressive craniotomy should be performed if consciousness does not improve within several hours.

True cytokeratin 8/18 immunohistochemistry is of no use in distinguishing between primary endocervical and endometrial adenocarcinomas in a tissue microarray study.

The choice of appropriate therapeutic plans for primary endocervical adenocarcinomas and endometrial adenocarcinomas depends on the site of origin of the tumor. The purpose of this study was to make clear whether the immunohistochemistry of the true cytokeratin 8/18 monoclonal antibody (Leica Microsystems, Newcastle, United Kingdom), instead of CAM 5.2 (Becton Dickinson Biosciences, San Jose, CA), has potential use in distinguishing between endocervical adenocarcinomas and endometrial adenocarcinomas. A tissue microarray was constructed using paraffin-embedded, formalin-fixed tissues from 34 hysterectomy specimens, including 14 endocervical adenocarcinomas and 20 endometrial adenocarcinomas. Using the Bond-Max autostainer (Leica Microsystems) and the associated Bond Refine Polymer Detection Kit, tissue array sections were immunostained with cytokeratin 8, 18, and 8/18 commercially available antibodies. The immunohistochemical expressions of all 3 markers, cytokeratin 8, 18, and 8/18 showed nonsignificant (P>0.05) frequency differences between the immunostaining results (positive vs. negative) in tumors of both gynecologic adenocarcinomas. Although CAM 5.2 has been reported to be helpful in distinguishing between primary endocervical adenocarcinomas and endometrial adenocarcinomas, we could not verify this point of view using the true cytokeratin 8/18 monoclonal antibody (Leica Microsystems). It has often been mistakenly cited that CAM 5.2 reacts with cytokeratin 8 and 18, and the results herein confer that there is a wrong impression that cytokeratin 8/18 is differentially expressed in these 2 gynecologic malignancies. In conclusion, the true cytokeratin 8/18 monoclonal antibody is of no use in distinguishing between primary endocervical adenocarcinomas and endometrial adenocarcinomas.

Assessment of abnormal brain structures and networks in major depressive disorder using morphometric and connectome analyses

BACKGROUND It is hypothesized that the phenomenology of major depressive disorder (MDD) is subserved by disturbances in the structure and function of brain circuits; however, findings of structural abnormalities using MRI have been inconsistent. Generalized q-sampling imaging (GQI) methodology provides an opportunity to assess the functional integrity of white matter tracts in implicated circuits. METHODS The study population was comprised of 16 outpatients with MDD (mean age 44.81±2.2 years) and 30 age- and gender-matched healthy controls (mean age 45.03±1.88 years). We excluded participants with any other primary mental disorder, substance use disorder, or any neurological illnesses. We used T1-weighted 3D MRI with voxel-based morphometry (VBM) and vertex-wise shape analysis, and GQI with voxel-based statistical analysis (VBA), graph theoretical analysis (GTA) and network-based statistical (NBS) analysis to evaluate brain structure and connectivity abnormalities in MDD compared to healthy controls correlates with clinical measures of depressive symptom severity, Hamilton Depression Rating Scale 17-item (HAMD) and Hospital Anxiety and Depression Scale (HADS). RESULTS Using VBM and vertex-wise shape analyses, we found significant volumetric decreases in the hippocampus and amygdala among subjects with MDD (p<0.001). Using GQI, we found decreases in diffusion anisotropy in the superior longitudinal fasciculus and increases in diffusion probability distribution in the frontal lobe among subjects with MDD (p<0.01). In GTA and NBS analyses, we found several disruptions in connectivity among subjects with MDD, particularly in the frontal lobes (p<0.05). In addition, structural alterations were correlated with depressive symptom severity (p<0.01). LIMITATIONS Small sample size; the cross-sectional design did not allow us to observe treatment effects in the MDD participants. CONCLUSIONS Our results provide further evidence indicating that MDD may be conceptualized as a brain disorder with abnormal circuit structure and connectivity.

Population dose from medical exposure in Taiwan for 2008

PURPOSE The largest contribution to the population dose from man-made ionizing radiation sources is the medical exposure. Exposure to patients from medical examinations is of interest because it is a global indicator for the quality of radiology practice. Due to the different healthcare systems and the considerable variations in the equipment and manpower in radiology, the population dose from medical exposure varies by a large extent in different countries. This dose from different diagnostic procedures provides information that can be used to establish national reference levels. It is also useful to determine the priority in terms of dose reduction so as to optimize the protection of patients in a cost-effective manner. In the present work, the collective effective doses due to different medical modalities were estimated for the Taiwan population in 2008. METHODS The collective effective dose from medical exposure was calculated using information on the number of procedures and the average effective dose per procedure. The frequency of procedures was extracted from the National Health Insurance (NHI) research database. The enrollment of Taiwan population in the NHI program was 99.48% in 2008. The average effective dose per procedure was derived from hospital surveys, measured data, and published results. RESULTS Estimates of the collective effective dose were made for different medical modalities, i.e., the conventional radiography and fluoroscopy, computed tomography, interventional fluoroscopy, nuclear medicine, and dental radiography. Each modality was further divided into relevant classes by the body part or organ system. Among 23 037 031 Taiwan population in 2008, the annual examination frequencies per 1000 population were 550, 55.1, 15.6, 13.6, and 112 for the conventional radiography and fluoroscopy, computed tomography, interventional fluoroscopy, nuclear medicine, and dental radiography, respectively. The corresponding collective effective doses were 3277, 8608, 2743, 2303, and 28 man-Sv, respectively. Thus, the average effective dose per caput was 0.74 mSv, which was in the range of 0.3-1.5 mSv for the 12 European countries estimated for 2008. CONCLUSIONS In the period from 1997 to 2008, the procedure frequency per 1000 population increased by a factor of 2.3 for computed tomography, 2.2 for interventional fluoroscopy, 1.8 for conventional radiography and fluoroscopy, and 1.5 for nuclear medicine. It demonstrated that the medical utilization of imaging facilities raised rapidly.

Sensitizing effect of 3-methyladenine on radiation-induced cytotoxicity in radio-resistant HepG2 cells in vitro and in tumor xenografts.

Many recent efforts have focused on targeting cell death pathways for discovering new cancer therapies. The relative resistance of liver cancer cells to ionizing radiation (IR) and chemotherapeutic agents due to autophagic response limits the available treatment options for this type of cancer. In this study, 3-methyladenine (3-MA), an autophagy inhibitor, was investigated for its potential to enhance radio-sensitivity under radio-resistant conditions both in vitro and in vivo. Hep3B and HepG2 cells were used to examine the radio-resistance of liver cancer cells. The results show that Hep3B cells respond to irradiation with increased apoptotic cell death and that HepG2 is radio-resistant due to the IR-induced autophagy, as verified by DNA fragmentation, electron microscopy, acidic vesicular organelle formation, and Western blot analysis. Application of IR with 3-MA to inhibit autophagy simultaneously suppressed the expression of LC3 and enhanced cell death. The tumor xenograft model in nude mice verified the synergistic cytotoxic effect of 3-MA and IR, which resulted in significant repression of tumor growth. The results demonstrate that IR-induced autophagy provides a self-protective mechanism against radiotherapy in HepG2 cells. In addition, 3-MA enhances the cytotoxicity of IR in cell models and suppresses tumor growth in animal models. Based on the results, application of 3-MA, or other autophagy inhibitors, could be used as an adjuvant for radiotherapy when radio-resistance develops as a result of autophagy response.

Preliminary experience of percutaneous intralesional bleomycin injection for the treatment of orbital lymphatic–venous malformation refractory to surgery

Preliminary experience of percutaneous intralesional bleomycin injection for the treatment of orbital lymphaticevenous malformation refractory to surgery C.-Y. Shen , M.-C. Wu , Y.-S. Tyan , C.-H. Ou , T.-Y. Chen , H.-F. Wong d,e,* Department of Medical Imaging, Chung Shan Medical University Hospital and School of Medicine, School of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan Department of Radiology, E-Da Hospital, I-Shou University, Kaohsiung, Taiwan Department of Radiology, Chang Bing Show Chwan Memorial Hospital, Changhua, Taiwan Department of Neuroradiology, Chang Gung Memorial Hospital, Linkou, Taiwan Chang Gung University, College of Medicine, Taoyuan, Taiwan

Progesterone receptor does not improve the performance and test effectiveness of the conventional 3-marker panel, consisting of estrogen receptor, vimentin and carcinoembryonic antigen in distinguishing between primary endocervical and endometrial adenocarcinomas in a tissue microarray extension study.

ObjectiveEndocervical adenocarcinomas (ECA) and endometrial adenocarcinomas (EMA) are uterine malignancies that have differing biological behaviors. The choice of an appropriate therapeutic plan rests on the tumors site of origin. In this study, we propose to evaluate whether PR adds value to the performance and test effectiveness of the conventional 3-marker (ER/Vim/CEA) panel in distinguishing between primary ECA and EMA.MethodsA tissue microarray was constructed using paraffin-embedded, formalin-fixed tissues from 38 hysterectomy specimens, including 14 ECA and 24 EMA. Tissue microarray (TMA) sections were immunostained with 4 antibodies, using the avidin-biotin complex (ABC) method for antigen visualization. The staining intensity and extent of the immunohistochemical (IHC) reactions were appraised using a semi-quantitative scoring system.ResultsThe three markers (ER, Vim and CEA) and their respective panel expressions showed statistically significant (p < 0.05) frequency differences between ECA and EMA tumors. Although the additional ancillary PR-marker also revealed a significant frequency difference (p < 0.05) between ECA and EMA tumors, it did not demonstrate any supplementary benefit to the 3-marker panel.ConclusionAccording to our data, when histomorphological and clinical doubt exists as to the primary site of origin, we recommend that the conventional 3-marker (ER/Vim/CEA) panel is easier, sufficient and appropriate to use in distinguishing between primary ECA and EMA. Although the 4-marker panel containing PR also reveals statistically significant results, the PR-marker offers no supplemental benefit to the pre-existing 3-marker (ER/Vim/CEA) panel in the diagnostic distinction between ECA and EMA.

Color Doppler Twinkling Artifact and Clinical Use

The color Doppler twinkling artifact manifests as a rapidly changing mixture of red and blue colors behind a strongly reflecting structure. Spectral Doppler analysis of the twinkling artifact does not yield a flow spectrum. It is important to recognize this artifact because it may lead to misdiagnosis of vascular flow within a tissue. Additionally, the artifact may be considered a sonographic sign in the detection of calcifications and calculi. In this article, we review the history of the interesting phenomenon and its clinical use, as well as our personal experiences of the artifact.

Abdominal Aortic Dissection with Acute Mesenteric Ischemia in a Patient with Marfan Syndrome

Marfan syndrome is an autosomal dominant inherited disorder of connective tissue, with various complications manifested primarily in the cardiovascular system. It potentially leads to aortic dissection and rupture, these being the major causes of death. We report a patient who complained of acute abdominal pain, which presented as acute mesenteric ischemia combined with abdominal aortic dissection. Echocardiography showed enlargement of the aortic root and mitral valve prolapse. Abdominal computed tomography scan revealed acute mesenteric ischemia due to abdominal aortic dissection. Finally, the patient underwent surgery of aortic root replacement and had a successful outcome. Therefore, we suggest that for optimal risk assessment and monitoring of patients with Marfan syndrome, both aortic stiffness and the diameter of the superior mesenteric vein compared with that of the superior mesenteric artery are useful screening methods to detect acute mesenteric ischemia secondary to abdominal aortic dissection. Early diagnosis and early treatment can decrease the high mortality rate of patients with Marfan syndrome.